Testing device, testing method, and program
Patent Information
- Application Number
- JP2023137536
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-08-25
- Publication Date
- 2025-03-07
Smart Images
Figure 2025031361000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a test apparatus, a test method, and a program. [Background technology]
[0002] Patent document 1 states, "The solar cell was characterized as follows: The external quantum efficiency (EQE) was estimated using the cell response at different wavelengths (measured with a white light halogen lamp combined with a bandpass filter)." (
[0121] ) [Prior art document] [Patent documents] [Patent Document 1] JP 2021-9950 A Summary of the Invention
[0003] In a first aspect of the present invention, there is provided a test apparatus comprising: a light source, an electrical measurement unit that measures a photoelectric signal obtained by a light emitting element under test performing photoelectric conversion of light irradiated from the light source, and a calculation unit that calculates a pseudo external quantum efficiency that is correlated with an intrinsic external quantum efficiency of the light emitting element under test based on the irradiation intensity of light irradiated from the light source to the light emitting element under test, an emission wavelength related to the emission of the light emitting element under test, and the measured photoelectric signal of the light emitting element under test.
[0004] In the above-mentioned testing apparatus, the calculation unit may use the pseudo external quantum efficiency calculated in advance for a reference light-emitting element and a correction coefficient based on the actual external quantum efficiency calculated in advance for an emission test of the reference light-emitting element to calculate an estimate of the actual external quantum efficiency of the light-emitting element to be tested from the pseudo external quantum efficiency of the light-emitting element to be tested based on the actual external quantum efficiency.
[0005] In any of the above test devices, the reference light-emitting element may be an ideal light-emitting element that conforms to the design values of the light-emitting element to be tested, or a light-emitting element that is included in the same production lot as the light-emitting element to be tested and meets predetermined acceptance criteria.
[0006] In any of the above test devices, the emission wavelength of the light-emitting element to be tested may be a wavelength according to a design value of the reference light-emitting element, a wavelength measured in advance by the emission test of the reference light-emitting element, or a wavelength according to a design value of the light-emitting element to be tested.
[0007] Any of the above test devices may further include a light emission control unit that causes the reference light emitting element to emit light. Any of the above test devices may further include a light measurement unit that measures the wavelength and light emission intensity of light from the reference light emitting element. In any of the above test devices, the calculation unit may calculate the pseudo external quantum efficiency of the reference light emitting element based on the irradiation intensity of light irradiated from the light source to the reference light emitting element, the wavelength of the reference light emitting element measured as the emission wavelength related to the light emission of the light emitting element to be tested, and the measured photoelectric signal of the reference light emitting element. In any of the above test devices, the calculation unit may calculate the true external quantum efficiency of the reference light emitting element based on the measured wavelength and light emission intensity of the reference light emitting element and the current input to the reference light emitting element by the light emission control unit. In any of the above test devices, the calculation unit may calculate the correction coefficient by dividing the pseudo external quantum efficiency by the true external quantum efficiency.
[0008] Any of the above test devices may further include an optical system that irradiates light from the light source incident in one direction onto the reference light-emitting element, and irradiates light from the reference light-emitting element incident in the other direction onto the light measurement unit.
[0009] In any of the above test devices, the electrical measurement unit may measure the photoelectric signal obtained by photoelectrically converting light collectively irradiated from the light source to each of the plurality of light-emitting elements to be tested. In any of the above test devices, the calculation unit may calculate the pseudo external quantum efficiency of each of the plurality of light-emitting elements to be tested based on the irradiation intensity of light irradiated from the light source to the plurality of light-emitting elements to be tested, the emission wavelengths related to the emission of the plurality of light-emitting elements to be tested, and the photoelectric signal measured for each of the plurality of light-emitting elements to be tested.
[0010] In any of the above test devices, the calculation unit may use the pseudo external quantum efficiency calculated in advance for a reference light-emitting element and a correction coefficient based on the actual external quantum efficiency calculated in advance for an emission test of the reference light-emitting element to calculate an estimate of the actual external quantum efficiency of each of the plurality of light-emitting elements to be tested from the pseudo external quantum efficiency of each of the plurality of light-emitting elements to be tested based on the emission test.
[0011] In any one of the test apparatuses described above, the calculation section may use different correction coefficients depending on a production lot that includes the plurality of light emitting elements to be tested.
[0012] Any of the above test devices may further include a judgment unit that judges pass / fail of each of the plurality of light-emitting elements to be tested based on an estimated value of the intrinsic external quantum efficiency of each of the plurality of light-emitting elements to be tested.
[0013] Any of the above test devices may further include an emission control unit that causes the multiple light-emitting elements to be tested to emit light collectively. Any of the above test devices may further include a light measurement unit that measures a wavelength of a composite light obtained by combining light from each of the multiple light-emitting elements to be tested as the emission wavelength related to the emission of the multiple light-emitting elements to be tested. Any of the above test devices may further include an optical system that irradiates the multiple light-emitting elements to be tested with light incident from the light source in one direction, and irradiates the multiple light-emitting elements to be tested with composite light obtained by combining light incident from each of the multiple light-emitting elements to be tested in another direction, to the light measurement unit.
[0014] In a second aspect of the present invention, there is provided a test method, which includes, in any one of the above test devices, irradiating a light emitting element to be tested with light from a light source, measuring a photoelectric signal obtained by photoelectrically converting the irradiated light into the light emitting element to be tested, and calculating a pseudo external quantum efficiency correlated with an intrinsic external quantum efficiency of the light emitting element to be tested based on the irradiation intensity of the light irradiated from the light source to the light emitting element to be tested, an emission wavelength related to the emission of the light emitting element to be tested, and the measured photoelectric signal of the light emitting element to be tested.
[0015] In a second aspect of the present invention, there is provided a program, which causes a test apparatus for testing light-emitting elements to execute the steps of: irradiating a light-emitting element to be tested with light from a light source, measuring a photoelectric signal obtained by photoelectrically converting the irradiated light into the light-emitting element to be tested, and calculating a pseudo external quantum efficiency that is correlated with the original external quantum efficiency of the light-emitting element to be tested, based on the irradiation intensity of the light irradiated from the light source to the light-emitting element to be tested, the emission wavelength related to the emission of the light-emitting element to be tested, and the measured photoelectric signal of the light-emitting element to be tested.
[0016] The above summary of the invention does not list all of the features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]
[0017] [Figure 1] 1 is an example of an overall view showing an outline of a test apparatus 100 for testing a plurality of LEDs 10. FIG. [Diagram 2] 1 is an example of an overall view showing an outline of a test apparatus 100 for testing a plurality of LEDs 10. FIG. [Diagram 3] 1 is a flow diagram illustrating an example of a flow of a test method performed by the test apparatus 100. FIG. [Figure 4] FIG. 12 illustrates an example computer 1200 upon which aspects of the present invention may be embodied in whole or in part. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.
[0019] 1 and 2 are an example of an overall view showing an outline of a test apparatus 100 for testing a plurality of LEDs 10. In Fig. 1 and Fig. 2, an X-axis, a Y-axis, and a Z-axis are shown which are orthogonal to each other. The right direction on the paper is the positive X-axis direction, the upward direction on the paper is the positive Z-axis direction, and the direction into the paper is the positive Y-axis direction.
[0020] The test device 100 uses the photoelectric effect of the light-emitting element to calculate a pseudo external quantum efficiency that is correlated with the original external quantum efficiency of the light-emitting element based on a photoelectric signal output from the light-emitting element that is irradiated with light. The test device 100 according to this embodiment irradiates light collectively onto an LED group in which a plurality of LEDs 10 are formed on a wafer 15 that is an LED wafer, for example, and calculates the pseudo external quantum efficiency of each LED 10 based on a photoelectric signal output from each LED 10. The test device 100 according to this embodiment further calculates an estimate of the original external quantum efficiency of each LED 10 from the pseudo external quantum efficiency of each LED 10. The test device 100 according to this embodiment tests the optical characteristics of the LED 10 by calculating the external quantum efficiency of the LED 10 in this way.
[0021] In this embodiment, the LED 10 is a micro LED with a dimension of 100 μm or less. Instead of a micro LED, the LED 10 may be a mini LED with a dimension of more than 100 μm and less than 200 μm, an LED with a dimension of more than 200 μm, or another light-emitting element such as an LD. These are all examples of light-emitting elements to be tested and light-emitting elements to be used as a reference.
[0022] In this embodiment, the LEDs 10 are not electrically connected to each other on the wafer 15. The LED group is a back-emitting type in which the light-emitting surfaces of the LEDs 10 face the wafer 15, and the wafer 15 transmits light. Two terminals 11 are formed on each LED 10 at a distance from each other in the Y-axis direction. The terminals 11 of the LEDs 10 do not face the wafer 15. In addition, for a back-emitting type LED group such as that in this embodiment, the LEDs 10 and the wafer 15 on which the LEDs 10 are mounted may be collectively called a wafer. In addition, the LED group may be a front-emitting type in which the light-emitting surfaces of the LEDs 10 do not face the wafer 15, and in this case, the wafer 15 may not transmit light, and the terminals 11 of the LEDs 10 may not face the wafer 15, but may face the wafer 15. When each terminal 11 of the multiple LEDs 10 faces the wafer 15, the wafer 15 may have a via extending in the Z-axis direction at the position of each terminal 11 so as to contact a power supply probe to each terminal 11.
[0023] In addition, multiple LEDs 10 may be formed on a wafer provided with electrical wiring, or on a glass-based panel (PLP) having a roughly rectangular outer shape, and electrically connected to each other to form units or cells.
[0024] The test device 100 according to this embodiment includes, for example, a mounting section 110, an electrical connection section 120, a light source 130, an optical system 140, an electrical measurement section 150, an emission control section 160, a light measurement section 170, a calculation section 180, a determination section 190, a storage section 200, and a shielding section 210. In Figures 1 and 2, the flow of signals between each component is indicated by solid black arrows.
[0025] The LED group is placed on the positive side of the Z axis on the placement unit 110. The LED group including the plurality of LEDs 10 to be tested is placed on the placement unit 110. The placement unit 110 may further directly place one or a plurality of individualized LEDs 10 serving as a reference, or may place an LED group including one or a plurality of LEDs 10 serving as a reference.
[0026] The mounting part 110 in the illustrated example has a substantially circular outer shape in a plan view from the Z-axis direction, but may have other outer shapes. The mounting part 110 has a holding function such as a vacuum chuck or an electrostatic chuck, and holds the wafer 15 of the LED group placed thereon. The mounting part 110 has a through hole 111 in the center of the XY plane so as not to block light that is irradiated onto the multiple LEDs 10 through the wafer 15 from the light source 130, or light that is emitted by the multiple LEDs 10 and passes through the wafer 15. The mounting part 110 holds the wafer 15 around the through hole 111. Note that the through hole 111 is indicated by a dashed line in FIG. 1 and FIG. 2.
[0027] The electrical connection unit 120 is, for example, a probe card (probe substrate), and is electrically connected to the terminals 11 of the LEDs 10 included in the LED group to be tested. The electrical connection unit 120 according to this embodiment is further electrically connected to the terminals 11 of one or more individualized LEDs 10 serving as a reference, or to the terminals 11 of an LED group including one or more LEDs 10 serving as a reference.
[0028] The electrical connection unit 120 has a substrate 121 and a plurality of probes 123. The substrate 121 is provided with an electric circuit and a plurality of electric wirings. The plurality of probes 123 are provided on one main surface of the substrate 121 and protrude from the one main surface of the substrate 121. Each of the plurality of probes 123 can come into contact with the terminal 11 of each LED 10 when the substrate 121 faces the group of LEDs on the mounting unit 110.
[0029] The electrical connection unit 120 moves two-dimensionally in the XY plane and moves up and down in the Z-axis direction. In Fig. 1 and Fig. 2, the movement direction of the electrical connection unit 120 is indicated by a hollow arrow. For example, the electrical connection unit 120 moves so that the LEDs 10 are positioned between the electrical connection unit 120 and the light source 130, and the probes 123 are brought into contact with the terminals 11 of the LEDs 10 from the Z-axis positive side of the wafer 15. The other end of each probe 123, opposite to the end that contacts the terminal 11, is electrically connected to electrical wiring provided on the substrate 121. The electrical wiring of each probe 123 extends from the side of the substrate 121 and is electrically connected to the electrical measurement unit 150 and the light emission control unit 160.
[0030] The light source 130 irradiates light to one or more LEDs 10. In this embodiment, the light source 130 irradiates light to one or more LEDs 10 via an optical system 140, as shown in Fig. 1. In Fig. 1, the light from the light source 130 is indicated by hatching.
[0031] The light source 130 is, for example, a white light source or a light source that emits light of a specific wavelength. When the light source 130 that is a white light source is used, a filter that filters light in the infrared region may be placed between the light source 130 and the LED 10 to prevent the LED 10 from becoming hot. When the light source 130 that emits light of a specific wavelength is used, the light source 130 may be set to emit light of the reactive wavelength of the LED 10, that is, light of a wavelength at which the LED 10 can output a photoelectric signal. As an example, when the design values of the emission wavelength and reactive wavelength of the LED 10 are 446 nm and 560 nm, the light source 130 may be set to emit light in a wavelength range of 560 nm ± several nm. When the light source 130 that emits light of the reactive wavelength of the LED 10 is used, the energy efficiency can be improved compared to a white light source because light of a wavelength other than the reactive wavelength of the LED 10 is not emitted. In this case, a filter that filters light of the infrared region, which is a wavelength range other than the reactive wavelength of the LED 10, can be eliminated.
[0032] The light source 130 may be a surface light source capable of uniformly irradiating light toward a plane on which an irradiation target is located. In this case, the irradiation intensity ([mW]) of the light irradiated from the light source 130 to each of the multiple LEDs 10 on the mounting section 110 is the irradiation intensity per unit area of the light from the light source 130 ([mW / cm 2 ]) to the area of each LED10 ([cm 2 ]) and stored in the storage unit 200. Alternatively, the light source 130 may emit light having an illuminance distribution in the plane, in which case the illuminance distribution may be measured in advance and stored in the storage unit 200. For example, the irradiation intensity of the light irradiated from the light source 130 to each position of the plurality of LEDs 10 on the mounting unit 110 may be measured in advance and stored in the storage unit 200, and the irradiation intensity for each position may be applied to the calculation of the external quantum efficiency described above. The irradiation intensity of the light irradiated from the light source 130 to each of the plurality of LEDs 10 is intended to be the irradiation intensity of the light having the reaction wavelength of the LED 10 among the light from the light source 130. For example, when the light source 130 is a white light source, the irradiation intensity of the light having the reaction wavelength of the LED 10 can be calculated by multiplying the irradiation intensity of the light having the entire wavelength range from the light source 130 by the ratio of the relative intensity of the reaction wavelength of the LED 10 when the total intensity of the entire wavelength range is set to 1. The light source 130 may be capable of adjusting the irradiation time, wavelength, intensity, etc. of the light irradiated onto the target.
[0033] The optical system 140 irradiates the light incident from the light source 130 to one or more LEDs 10. As shown in FIG. 1 and FIG. 2, the optical system 140 according to this embodiment is arranged such that one side is connected to the light source 130 and the light measurement unit 170, and the other side faces the LED group on the mounting unit 110. In this embodiment, the optical system 140 is a group of optical elements common to the light source 130 and the light measurement unit 170. The optical system 140 enables photoelectric signal measurement and wavelength measurement of the LED 10 to be performed using a bidirectional optical path. Specifically, the optical system 140 irradiates the light from the light source 130 incident in one direction to the LED 10, and irradiates the light measurement unit 170 with the light from the LED 10 incident in the other direction.
[0034] 1, the optical system 140 according to the present embodiment diffuses the light from the light source 130, thereby irradiating the light from the light source 130 to the multiple LEDs 10 at once. That is, the projection surface in the XY plane on the mounting part 110 of the light from the light source 130 emitted via the optical system 140 covers at least the multiple LEDs 10 of the LED group.
[0035] The optical system 140 according to the present embodiment also irradiates the light measurement unit 170 with a composite light obtained by combining the light from each of the plurality of LEDs 10. In FIG. 2, the composite light from the plurality of LEDs 10 is indicated by diagonal lines. As shown in FIG. 2, the optical system 140 guides the diffused light from the plurality of LEDs 10 to the light measurement unit 170 by collecting the diffused light. As shown in FIG. 2, the optical system 140 according to the present embodiment guides the light from the plurality of LEDs 10 to both the light source 130 and the light measurement unit 170. Alternatively, the optical system 140 may be configured to guide the light from the plurality of LEDs 10 only to the light measurement unit 170 and not to the light source 130.
[0036] The optical system 140 according to the present embodiment has a bifurcated fiber 141. The bifurcated fiber 141 is a Y-shaped optical fiber. The bifurcated end of the bifurcated fiber 141 is connected to the light source 130 and the light measurement unit 170. The optical system 140 may have a multi-branched fiber such as a trifurcated fiber or a quadruple-branched fiber instead of the bifurcated fiber 141. In this case, the test device 100 may include two or more light sources 130, and each light source 130 may be connected to each end of the bifurcated side of the multi-branched fiber. In this case, the optical system 140 may irradiate the light from the multiple light sources 130 that emit light of different wavelength bands to the multiple LEDs 10 together. For example, the optical system 140 may irradiate the light from three light sources 130 that emit light of each RGB response wavelength of the LED 10 together to the LED 10. In the case where the light source 130 emits light in a specific wavelength band, by connecting multiple light sources 130 to the optical system 140 in this manner, the wavelength bandwidth of the light irradiated to the LED 10 can be broadened, and the LED 10 can more reliably perform photoelectric conversion.
[0037] Furthermore, the optical system 140 may further include a lens unit 143 including one or more lenses, and the lens unit 143 is disposed on an optical path in the optical system 140. Furthermore, the lens unit 143 converges the diffused light emitted from the multiple LEDs 10 and causes the light to enter the bifurcated fiber 141, as shown in FIG.
[0038] With such a mutual connection configuration of the optical system 140, the light source 130, and the light measurement unit 170, the test apparatus 100 can perform photoelectric signal measurement and wavelength measurement of multiple LEDs 10 in both directions using the common optical system 140. The test apparatus 100 does not need to change the device configuration or move the LEDs 10 when finishing one of the photoelectric signal measurement and the wavelength measurement and starting the other.
[0039] The electrical measurement unit 150 measures a photoelectric signal obtained by photoelectrically converting light irradiated from the light source 130 by the LED 10 under test. The electrical measurement unit 150 according to this embodiment measures a photoelectric signal obtained by photoelectrically converting light irradiated collectively from the light source 130 by each of the multiple LEDs 10 under test. The electrical measurement unit 150 according to this embodiment further measures a photoelectric signal obtained by photoelectrically converting light irradiated from the light source 130 by one or multiple reference LEDs 10.
[0040] More specifically, the electrical measurement unit 150 measures the current value of the current output from each LED 10 via the electrical connection unit 120. The electrical measurement unit 150 outputs the current value measured for each LED 10 to the calculation unit 180. Note that the electrical measurement unit 150 may measure a voltage value corresponding to the current value instead of the current value of the current output from the LED 10.
[0041] The light emission control unit 160 causes the LED 10 to emit light by supplying a current or voltage of a predetermined magnitude to the LED 10. The light emission control unit 160 according to this embodiment causes the multiple LEDs 10 to be tested to emit light collectively by supplying a current or voltage of a predetermined magnitude to the multiple LEDs 10 to be tested via the electrical connection unit 120. The light emission control unit 160 according to this embodiment further causes one or more reference LEDs 10 to emit light.
[0042] The light measuring unit 170 measures the wavelength of light from the LED 10. The light measuring unit 170 according to this embodiment measures the wavelength of a composite light obtained by combining the light from each of the multiple LEDs 10 that receive light through the optical system 140. The composite light obtained by combining the light from each of the multiple LEDs 10 is an example of the emission wavelength related to the emission of the multiple LEDs 10 to be tested. The light measuring unit 170 may measure the wavelength of light emitted by one or more LEDs 10 in each group, for each group obtained by dividing all the LEDs 10 to be tested into several groups. The light measuring unit 170 may also measure the wavelength of light from each of the multiple LEDs 10 to be tested individually. The light measuring unit 170 according to this embodiment further measures the wavelength and emission intensity of light from one or more LEDs 10 to be used as a reference.
[0043] The light measurement unit 170 according to this embodiment includes, for example, a wavemeter. The light measurement unit 170 may measure the wavelength of the combined light from the multiple LEDs 10 and specify the intensity distribution of the combined light wavelength. The light measurement unit 170 may specify the peak wavelength or half-width of the combined light based on the intensity distribution of the combined light, and may measure the dominant wavelength, which is the wavelength corresponding to the color of the combined light when viewed with the eye. The light measurement unit 170 may include a spectrometer, an optical spectrum analyzer, or the like, instead of a wavemeter. The light measurement unit 170 outputs the measured wavelength and emission intensity to the calculation unit 180.
[0044] The calculation unit 180 calculates a pseudo external quantum efficiency that is correlated with the intrinsic external quantum efficiency of the LED 10 under test. More specifically, the calculation unit 180 calculates the pseudo external quantum efficiency based on the irradiation intensity of the light emitted from the light source 130 to the LED 10 under test, the emission wavelength related to the emission of the LED 10 under test, and the measured photoelectric signal of the LED 10 under test. The calculation unit 180 further calculates an estimate of the intrinsic external quantum efficiency of the LED 10 under test based on the emission test from the pseudo external quantum efficiency of the LED 10 under test.
[0045] The calculation unit 180 according to this embodiment calculates the pseudo external quantum efficiency of each of the LEDs 10 to be tested. More specifically, the calculation unit 180 calculates the pseudo external quantum efficiency of each of the LEDs 10 to be tested based on the irradiation intensity of the light emitted from the light source 130 to the LEDs 10 to be tested, the emission wavelength of the LEDs 10 to be tested, and the photoelectric signal measured for each of the LEDs 10 to be tested. The calculation unit 180 further calculates an estimate of the actual external quantum efficiency of each of the LEDs 10 to be tested by the light emission test from the pseudo external quantum efficiency of the LEDs 10 to be tested.
[0046] The calculation unit 180 may obtain data on the irradiation intensity irradiated from the light source 130 to the one or more LEDs 10 to be tested from outside the test apparatus 100, for example, by a user input, and store the data in the storage unit 200. Note that the irradiation intensity irradiated from the light source 130 to the one or more LEDs 10 to be tested may be measured by placing the light measurement unit 170 on the placement unit 110 in place of the LED group in the test apparatus 100.
[0047] The calculation unit 180 uses, as the emission wavelength related to the emission of the plurality of LEDs 10 to be tested, for example, the wavelength of the composite light of the plurality of LEDs 10 input from the light measurement unit 170. Alternatively, the calculation unit 180 may use the wavelength of a reference LED 10 input from the light measurement unit 170 as the emission wavelength related to the emission of one or more LEDs 10 to be tested.
[0048] The above-mentioned reference LED 10 may be an LED 10 exhibiting good light emission characteristics, the light emission characteristics of which can be compared with those of the test LED 10. The reference LED 10 may be, for example, an ideal light emitting element conforming to the design value of the test LED 10, or may be an LED 10 that is included in the same manufacturing lot as the test LED 10 and satisfies a predetermined pass criterion. The predetermined pass criterion may be defined, for example, for each user who manufactures and sells the test LED 10.
[0049] The pseudo external quantum efficiency described above is calculated by the formula: EQE = [P / (I × E)] × 100, similar to the commonly known true external quantum efficiency. However, the true external quantum efficiency is based on the light emission efficiency, whereas the pseudo external quantum efficiency is based on the light receiving efficiency, so the true external quantum efficiency and the pseudo external quantum efficiency are different values. In the above derivation formula, when deriving the true external quantum efficiency, EQE is the true external quantum efficiency ([%]), P is the light emission intensity of the element ([mW]), I is the current value input to the element ([mA]), and E is the light energy, which is the value ([eV]) obtained by dividing the product of the Planck constant and the luminous flux in vacuum (1240 [nm eV]) by the light emission wavelength of the element ([nm]). When deriving the pseudo external quantum efficiency, EQE is the pseudo external quantum efficiency ([%]), P is the irradiation intensity of the light irradiated to the element ([mW]), I is the current value of the photoelectric signal output from the element ([mA]), and E is the light energy ([eV]) obtained by dividing the product of Planck's constant and the luminous flux in vacuum (1240 [nm eV]) by the emission wavelength of the element ([nm]).
[0050] It is understood that the pseudo external quantum efficiency has a positive correlation with the original external quantum efficiency. Therefore, the light-emitting properties of the light-emitting element can be evaluated by using the pseudo external quantum efficiency. For example, the correlation coefficient of a specific light-emitting element can be obtained by dividing the original external quantum efficiency of the light-emitting element by the pseudo external quantum efficiency of the light-emitting element. The correlation coefficient between the pseudo external quantum efficiency and the original external quantum efficiency of the light-emitting element can be different for each design value of the light-emitting element, that is, for each manufacturing lot of the light-emitting element.
[0051] Therefore, the calculation unit 180 according to the present embodiment uses a correction coefficient calculated in advance as the correlation coefficient corresponding to the LED 10 to be tested to calculate an estimate of the original external quantum efficiency of the LED 10 to be tested from the pseudo external quantum efficiency of the LED 10 to be tested by a light emission test. The calculation unit 180 uses a different correction coefficient according to a manufacturing lot including one or more LEDs 10 to be tested. Note that the multiple LEDs 10 formed on the same wafer 15 are LEDs 10 manufactured based on the same design values and are LEDs 10 included in the same manufacturing lot. The calculation unit 180 outputs the estimate of the original external quantum efficiency to the determination unit 190.
[0052] The determination unit 190 determines whether each of the LEDs 10 to be tested is good or bad based on the estimated value of the intrinsic external quantum efficiency of each of the LEDs 10 to be tested. For example, the determination unit 190 may determine whether each of the LEDs 10 to be tested is good or bad by comparing the intrinsic external quantum efficiency of the LED 10 to be a reference stored in the storage unit 200, that is, by comparing the intrinsic external quantum efficiency with a threshold value that is a predetermined pass criterion. For example, the determination unit 190 may identify an LED 10 whose intrinsic external quantum efficiency is an outlier based on a statistical value of the intrinsic external quantum efficiency of the LEDs 10 to be tested, and determine the LED 10 to be bad. The determination unit 190 may further exclude an LED 10 whose intrinsic external quantum efficiency is determined to be bad from the target of subsequent testing.
[0053] The shielding portion 210 blocks light other than the light from the light source 130 and the LED 10. In this embodiment, the surface of the shielding portion 210 is painted black to prevent diffuse reflection of light on the surface. As shown in FIG. 1, the shielding portion 210 is provided so as to form a sealed space with the lens unit 143, the mounting portion 110, and the wafer 15, and this configuration blocks light other than the light from the light source 130 and the LED 10.
[0054] Fig. 3 is an example of a flow diagram illustrating the flow of a test method by the test apparatus 100. The operation flow shown in Fig. 3 starts when, with an LED group placed on the placement section 110, the user performs an input to the test apparatus 100 to start testing the LED group, for example.
[0055] The test device 100 calculates the original external quantum efficiency of the reference LED 10 based on the light emission test of the reference LED 10 (step S101). More specifically, the light emission control unit 160 of the test device 100 causes the reference LED 10 to emit light by supplying a current of a predetermined magnitude to the reference LED 10 via the electrical connection unit 120 while the reference LED 10 is placed on the placement unit 110. The light measurement unit 170 receives light from the reference LED 10 via the optical system 140, measures the wavelength and light emission intensity of the received light, and outputs the measurement result to the calculation unit 180. The wavelength of the light may be, for example, the central wavelength of the combined light from the reference LEDs 10.
[0056] The calculation unit 180 calculates the original external quantum efficiency of the reference LED 10 based on the measured wavelength and emission intensity of the reference LED 10 and the current input to the reference LED 10 by the emission control unit 160. The calculation unit 180 calculates the original external quantum efficiency of the reference LED 10 by referring to a derivation formula for the original external quantum efficiency stored in the storage unit 200, for example.
[0057] The test device 100 calculates the pseudo external quantum efficiency of the reference LED 10 based on the photoelectric conversion test of the reference LED 10 (step S103). More specifically, the light source 130 of the test device 100 irradiates the reference LED 10 with light at a predetermined irradiation intensity via the optical system 140. The electrical measurement unit 150 measures the photoelectric signals obtained by photoelectrically converting the light irradiated by each of the reference LED 10 via the electrical connection unit 120, and outputs the measurement results to the calculation unit 180. The calculation unit 180 calculates the pseudo external quantum efficiency of each of the reference LED 10 based on the irradiation intensity of the light irradiated from the light source 130 to the reference LED 10, the wavelength of the reference LED 10 measured in step S101 as the emission wavelength related to the emission of the LED 10 to be tested, and the measured photoelectric signal of each of the reference LED 10.
[0058] The test apparatus 100 calculates the above-mentioned correction coefficient (step S105). More specifically, the calculation unit 180 of the test apparatus 100 calculates the correction coefficient by dividing the pseudo external quantum efficiency of each of the one or more reference LEDs 10 by the original external quantum efficiency of the one or more reference LEDs 10. When a plurality of reference LEDs 10 are used, the calculation unit 180 may derive an average value of the correction coefficients for the number of LEDs 10, which are calculated based on the individual pseudo external quantum efficiency of each LED 10 and the original external quantum efficiency common to all the LEDs 10, or may select a median value of the plurality of correction coefficients.
[0059] The test device 100 identifies the emission wavelength of the LED 10 to be tested based on the current test of the LED 10 to be tested (step S107). More specifically, the light emission control unit 160 of the test device 100 causes the LEDs 10 to emit light by supplying a current of a predetermined magnitude to the LEDs 10 to be tested via the electrical connection unit 120 while the LEDs 10 to be tested are placed on the placement unit 110. The light measurement unit 170 receives the combined light from the LEDs 10 to be tested via the optical system 140, measures the wavelength of the combined light received, and outputs the measurement result to the calculation unit 180. The calculation unit 180 identifies the wavelength of the combined light from the LEDs 10 to be tested as the emission wavelength of the LEDs 10 to be tested. The wavelength of the combined light may be, for example, the central wavelength of the combined light.
[0060] The test device 100 calculates the pseudo external quantum efficiency of the LED 10 under test based on the photoelectric conversion test of the LED 10 under test (step S109). More specifically, the light source 130 of the test device 100 irradiates the LEDs 10 under test with light at the irradiation intensity set in step S103 via the optical system 140. The electrical measurement unit 150 measures the photoelectric signal obtained by photoelectrically converting the light irradiated by each of the LEDs 10 under test via the electrical connection unit 120, and outputs the measurement result to the calculation unit 180. The calculation unit 180 calculates the pseudo external quantum efficiency of each of the LEDs 10 under test based on the irradiation intensity of the light irradiated from the light source 130 to the LEDs 10 under test, the wavelengths of the LEDs 10 under test measured in step S107 as the emission wavelengths related to the emission of the LEDs 10 under test, and the measured photoelectric signals of each of the LEDs 10 under test.
[0061] The test apparatus 100 calculates an estimate of the original external quantum efficiency of the LED 10 to be tested from the pseudo external quantum efficiency of the LED 10 to be tested using the correction coefficient (step S111). More specifically, the calculation unit 180 of the test apparatus 100 calculates an estimate of the original external quantum efficiency of each of the LEDs 10 to be tested from the pseudo external quantum efficiency of each of the LEDs 10 to be tested using the correction coefficient calculated in step S105. As an example, the calculation unit 180 calculates the original external quantum efficiency of each LED 10 by dividing the pseudo external quantum efficiency of each LED 10 by the correction coefficient. The calculation unit 180 outputs the calculation result to the determination unit 190.
[0062] The test apparatus 100 judges whether the LED 10 to be tested is good or bad based on the estimated value of the intrinsic external quantum efficiency (step S113), and the flow ends. More specifically, the judgment unit 190 of the test apparatus 100, for example, compares the intrinsic external quantum efficiency of each LED 10 input from the calculation unit 180 with a threshold value stored in the storage unit 200, judges the LED 10 whose intrinsic external quantum efficiency is less than the threshold value as bad, and excludes it from the target of the subsequent test.
[0063] The test apparatus 100 may change the order of the steps in the operation flow of FIG. 3, or may omit one or more steps. For example, the order of steps S101 and S103 may be reversed in the operation flow of FIG. 3. Steps S101 to S107 may be omitted. In this case, the test apparatus 100 may acquire in advance the correction coefficient calculated in step S105 and the emission wavelength related to the emission of the LED 10 to be tested measured in step S107, and store them in the storage unit 200. The irradiation intensity of the light source 130 in steps S103 and S109 may be measured in advance, or may be a set value input to the light source 130.
[0064] As described above, according to the testing apparatus 100 of this embodiment, the LED 10 under test is irradiated with light from the light source 130, a photoelectric signal obtained by photoelectrically converting the irradiated light by the LED 10 under test is measured, and a pseudo external quantum efficiency that is correlated with the original external quantum efficiency of the LED 10 under test is calculated based on the irradiation intensity of the light irradiated from the light source 130 to the LED 10 under test, the emission wavelength related to the light emitted by the LED 10 under test, and the measured photoelectric signal of the LED 10 under test.
[0065] As a comparative example of the test apparatus 100 according to the present embodiment, a device is assumed that calculates the true external quantum efficiency by measuring the wavelength and emission intensity of light emitted by applying a current of a predetermined magnitude to a light-emitting element to be tested. For example, in a semiconductor test, many light-emitting elements are arranged adjacent to each other, and when the semiconductor test is performed using the device, if many light-emitting elements are made to emit light at once, the light from adjacent light-emitting elements will mix, making it impossible to accurately measure the emission intensity of each light-emitting element. If the device is made to emit light sequentially to avoid this, it will take a long time to measure the emission intensity of all the light-emitting elements and calculate the true external quantum efficiency.
[0066] In contrast, the test apparatus 100 according to the present embodiment calculates the pseudo external quantum efficiency by measuring the photoelectric signal output by irradiating the light having a predetermined irradiation intensity to the light emitting element to be tested. Even when testing a semiconductor in which a large number of light emitting elements are arranged adjacent to each other, the test apparatus 100 can irradiate the light to the light emitting elements at once, measure the photoelectric signal of each light emitting element at the same time, and calculate the pseudo external quantum efficiency of each light emitting element in parallel in time. Therefore, the test apparatus 100 can also calculate the estimated value of the true external quantum efficiency correlated with the pseudo external quantum efficiency of each light emitting element in parallel in time by using a correction coefficient calculated in advance for the light emitting element to be tested. As a result, the test apparatus 100 can significantly reduce the processing time required to calculate the estimated value of the true external quantum efficiency of each light emitting element, i.e., the test execution time, compared to the apparatus of the comparative example described above. The test apparatus 100 can also evaluate the light emitting characteristics of each light emitting element based on the pseudo external quantum efficiency of each light emitting element.
[0067] In the above embodiments, the light measurement unit 170 of the test device 100 has been described as being configured to measure the wavelength of the composite light obtained by combining the light from each of the plurality of LEDs 10 under test and the wavelength of the light from the reference LED 10 as the emission wavelength of the light emitted from the plurality of LEDs 10 under test. Furthermore, the calculation unit 180 of the test device 100 has been described as being configured to calculate the pseudo external quantum efficiency of each of the plurality of LEDs 10 under test using the photoelectric signal of each of the plurality of LEDs 10 under test measured by the electrical measurement unit 150, and the wavelength of the composite light or the wavelength of the reference LED 10 measured by the light measurement unit 170.
[0068] Alternatively, the light measuring unit 170 of the test device 100 may not measure at least one of the wavelength of the composite light obtained by combining the light from each of the LEDs 10 to be tested and the wavelength of the reference LED 10. Alternatively, the test device 100 may not include the light measuring unit 170, and in this case, the optical system 140 may not have the bifurcated fiber 141. When the test device 100 does not measure the wavelength of the composite light from the LEDs 10 to be tested and the wavelength of the reference LED 10, the test device 100 may use a wavelength according to the design value of the reference LED 10, a wavelength measured in advance by an emission test of the reference LED 10, or a wavelength according to the design value of the one or more LEDs 10 to be tested as the emission wavelength of the one or more LEDs 10 to be tested. Before calculating the pseudo external quantum efficiency of the LED 10 to be tested, the test device 100 may obtain data of these wavelengths from outside the test device 100, for example, by a user input, and store them in the storage unit 200. In this case, the calculation unit 180 of the test apparatus 100 further calculates the pseudo external quantum efficiency of each of the one or more LEDs 10 under test using the photoelectric signals of each of the one or more LEDs 10 under test measured by the electrical measurement unit 150 and these wavelengths.
[0069] In the above embodiments, the light measurement unit 170 of the test device 100 has been described as being configured to measure the wavelength and emission intensity of light from the reference LED 10 in order to calculate the correction coefficient by the calculation unit 180. Furthermore, the calculation unit 180 of the test device 100 has been described as being configured to calculate the pseudo external quantum efficiency of the reference LED 10 using the photoelectric signal of the reference LED 10 measured by the electrical measurement unit 150 and the wavelength of the reference LED 10 measured by the light measurement unit 170. The calculation unit 180 has been further described as being configured to calculate the original external quantum efficiency of the reference LED 10 based on the wavelength and emission intensity of the reference LED 10 measured by the light measurement unit 170 and the current input to the reference LED 10 by the light emission control unit 160. The calculation unit 180 has been further described as being configured to calculate the correction coefficient by dividing the pseudo external quantum efficiency of the reference LED 10 by the original external quantum efficiency of the reference LED 10.
[0070] Alternatively, the light measuring unit 170 of the test apparatus 100 does not need to measure the wavelength of light from the reference LED 10, and the calculation unit 180 may obtain a correction coefficient corresponding to the LED 10 under test from outside the test apparatus 100, for example, via a user input, and store the correction coefficient in the storage unit 200 before calculating an estimate of the inherent external quantum efficiency of the LED 10 under test. In this case, the calculation unit 180 of the test apparatus 100 further calculates an estimate of the inherent external quantum efficiency of the LED 10 under test from the pseudo external quantum efficiency calculated for the LED 10 under test, using the correction coefficient obtained from outside.
[0071] In the above embodiments, the test apparatus 100 may include another mechanism such as a prism in the optical system 140 instead of a branching fiber such as the two-branching fiber 141. In this case, the prism or the like has a functional configuration similar to that of the two-branching fiber 141 described in the above embodiments.
[0072] In the above embodiments, when the LED group is configured such that a plurality of LEDs are formed on a glass-based panel (PLP) having an approximately rectangular outer shape on which electrical wiring is formed, the electrical connection portion may be configured to bring a probe into contact with each of the row and column wiring arranged on two side surfaces of the panel.
[0073] Various embodiments of the present invention may be described with reference to flow charts and block diagrams, where the blocks may represent (1) stages of a process in which operations are performed or (2) sections of an apparatus responsible for performing the operations. Particular stages 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. Dedicated circuitry may include digital and / or analog hardware circuitry and may include integrated circuits (ICs) and / or discrete circuits. Programmable circuitry may include reconfigurable hardware circuitry including logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, memory elements such as flip-flops, registers, field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), and the like.
[0074] A computer-readable medium may include any tangible device capable of storing instructions that are executed by a suitable device, such that the computer-readable medium having instructions stored thereon comprises an article of manufacture that includes instructions that can be executed to create means for performing the operations specified in the flowcharts or block diagrams. Examples of computer-readable media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, and the like. More specific examples of computer-readable media may include floppy disks, diskettes, hard disks, random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), electrically erasable programmable read-only memories (EEPROMs), static random access memories (SRAMs), compact disk read-only memories (CD-ROMs), digital versatile disks (DVDs), Blu-ray (RTM) disks, memory sticks, integrated circuit cards, and the like.
[0075] The computer readable instructions may include either assembler instructions, Instruction Set Architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including object-oriented programming languages such as Smalltalk®, JAVA®, C++, etc., and conventional procedural programming languages such as the “C” programming language or similar programming languages.
[0076] The computer-readable instructions may be provided to a processor or programmable circuit of a programmable data processing device such as a computer, either locally or over a wide area network (WAN) such as a local area network (LAN), the Internet, etc., to execute the computer-readable instructions to create a means for performing the operations specified in the flowchart or block diagram. Here, the computer may be a PC (personal computer), a tablet computer, a smartphone, a workstation, a server computer, a general-purpose computer, or a special-purpose computer, or may be a computer system in which multiple computers are connected. Such a computer system in which multiple computers are connected is also called a distributed computing system, and is a computer in the broad sense. In a distributed computing system, each of the multiple computers executes a part of a program, and the multiple computers collectively execute a program by transferring data during program execution between the computers as necessary.
[0077] Examples of processors include computer processors, central processing units (CPUs), processing units, microprocessors, digital signal processors, controllers, microcontrollers, etc. A computer may have one processor or multiple processors. In a multiprocessor system with multiple processors, each processor executes a part of a program, and the multiple processors collectively execute a program by passing data during program execution between the processors as necessary. For example, in executing multitasks, each of the multiple processors may execute a part of each task in small chunks by switching tasks for each time slice. In this case, which part of a program each processor executes changes dynamically. Which part of a program each of the multiple processors executes may be statically determined by programming that takes the multiprocessor into consideration.
[0078] 4 illustrates an example of a computer 1200 in which aspects of the present invention may be embodied in whole or in part. Programs installed on the computer 1200 may cause the computer 1200 to function as or perform operations associated with an apparatus or one or more sections of the apparatus according to an embodiment of the present invention, and / or to perform a process or steps of the process according to an embodiment of the present invention. Such programs may be executed by the CPU 1212 to cause the computer 1200 to perform specific operations associated with some or all of the blocks of the flowcharts and block diagrams described herein.
[0079] The computer 1200 according to this embodiment includes a CPU 1212, a RAM 1214, a graphic controller 1216, and a display device 1218, which are connected to each other 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.
[0080] The CPU 1212 operates according to a program stored in the ROM 1230 and the RAM 1214, thereby controlling each unit. The graphic controller 1216 retrieves image data generated by the CPU 1212 into a frame buffer or the like provided in the RAM 1214 or into the graphic controller 1216 itself, and causes the image data to be displayed on the display device 1218.
[0081] The communication 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 programs 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 an IC card and / or writes programs and data to an IC card.
[0082] The ROM 1230 stores therein a boot program or the like executed by the computer 1200 upon activation, and / or a program that depends on the 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, and the like.
[0083] The programs are provided by a computer-readable medium such as a DVD-ROM 1201 or an IC card. The programs are read from the computer-readable medium, installed in the hard disk drive 1224, the RAM 1214, or the ROM 1230, which are also examples of computer-readable media, and executed by the CPU 1212. Information processing described in these programs is read by the computer 1200, and brings about cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be constructed by realizing information manipulation or processing according to the use of the computer 1200.
[0084] For example, when communication is performed 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 perform communication processing based on the processing described in the communication program. Under the control of the CPU 1212, the communication interface 1222 reads transmission data stored in a transmission buffer processing area provided in the RAM 1214, the hard disk drive 1224, the DVD-ROM 1201, or a recording medium such as an IC card, and transmits the read transmission data to the network, or writes reception data received from the network to a reception buffer processing area or the like provided on the recording medium.
[0085] Furthermore, the CPU 1212 may cause all or a necessary portion of a file or database stored in an external recording medium such as a hard disk drive 1224, a DVD-ROM drive 1226 (DVD-ROM 1201), an IC card, etc. to be read into the RAM 1214, and perform various types of processing on the data on the RAM 1214. The CPU 1212 then writes back the processed data to the external recording medium.
[0086] Various types of information, such as various types of programs, data, tables, and databases, may be stored in the recording medium and undergo information processing. The CPU 1212 may perform various types of processing on the data read from the RAM 1214, including various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information search / replacement, etc., as described throughout this disclosure and specified by the instruction sequence of the program, and write back the results to the RAM 1214. The CPU 1212 may also search for information in a file, database, etc. in the recording medium. For example, when a plurality of entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored in the recording medium, the CPU 1212 may search for an entry that matches a 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 obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.
[0087] The above-described programs or software modules may be stored in a computer-readable medium on the computer 1200 or in the vicinity of the computer 1200. Also, 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 medium, thereby providing the programs to the computer 1200 via the network.
[0088] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.
[0089] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]
[0090] 10 LED 11 Terminal 15 Wafer 100 Test Equipment 110 Placement section 111 Through hole 120 Electrical Connections 121 Substrate 123 Probe 130 light source 140 Optical system 150 Electrical Measurement Section 160 Light emission control unit 170 Light measurement unit 180 Calculation Section 190 Judgment section 200 Storage Unit 210 Shielding part 1200 Computer 1201 DVD-ROM 1210 Host Controller 1212 CPU 1214 RAM 1216 Graphics Controller 1218 Display Devices 1220 Input / Output Controller 1222 Communication Interface 1224 Hard Disk Drive 1226 DVD-ROM drive 1230 ROM 1240 Input / Output Chip 1242 Keyboard
Claims
1. A light source; an electrical measurement unit for measuring a photoelectric signal obtained by photoelectrically converting light irradiated from the light source by a light emitting element to be tested; a calculation unit that calculates a pseudo external quantum efficiency having a correlation with an original external quantum efficiency of the light-emitting element to be tested, based on an irradiation intensity of light irradiated from the light source to the light-emitting element to be tested, an emission wavelength related to the emission of the light-emitting element to be tested, and the measured photoelectric signal of the light-emitting element to be tested; A test apparatus comprising:
2. the calculation unit calculates an estimate of an actual external quantum efficiency of the light-emitting element to be tested based on the pseudo external quantum efficiency of the light-emitting element to be tested by a light-emission test, from the pseudo external quantum efficiency of the light-emitting element to be tested, by using a correction coefficient based on the pseudo external quantum efficiency calculated in advance for a reference light-emitting element and an actual external quantum efficiency calculated in advance for a light-emission test of the reference light-emitting element; 2. The test device of claim 1.
3. The reference light-emitting element is an ideal light-emitting element that conforms to a design value of the light-emitting element to be tested, or is a light-emitting element that is included in the same manufacturing lot as the light-emitting element to be tested and satisfies a predetermined pass criterion.
3. The test device according to claim 2.
4. The emission wavelength of the light emitting element to be tested is a wavelength according to a design value of the reference light emitting element, a wavelength previously measured by the light emission test of the reference light emitting element, or a wavelength according to a design value of the light emitting element to be tested.
3. The test device according to claim 2.
5. a light emission control unit that causes the reference light emitting element to emit light; a light measuring unit for measuring the wavelength and light emission intensity of light from the reference light emitting element; Further comprising: The calculation unit is Calculating the pseudo external quantum efficiency of the reference light-emitting element based on the irradiation intensity of light irradiated from the light source to the reference light-emitting element, the wavelength of the reference light-emitting element measured as the emission wavelength related to the emission of the light-emitting element to be tested, and the measured photoelectric signal of the reference light-emitting element; calculating the inherent external quantum efficiency of the reference light-emitting element based on the measured wavelength and the light-emitting intensity of the reference light-emitting element and a current input to the reference light-emitting element by the light-emission control unit; Calculating the correction coefficient by dividing the pseudo external quantum efficiency by the original external quantum efficiency.
3. The test device according to claim 2.
6. Further comprising an optical system that irradiates the light from the light source incident in one direction onto the reference light emitting element, and irradiates the light from the reference light emitting element incident in the other direction onto the light measurement unit.
6. A test device according to claim 5.
7. The electrical measurement unit measures the photoelectric signals obtained by photoelectrically converting light collectively irradiated from the light source by each of the plurality of light emitting elements to be tested, the calculation unit calculates the pseudo external quantum efficiency of each of the plurality of light-emitting elements to be tested based on the irradiation intensity of light irradiated from the light source to the plurality of light-emitting elements to be tested, the emission wavelengths related to the emission of the plurality of light-emitting elements to be tested, and the photoelectric signal measured for each of the plurality of light-emitting elements to be tested. A test device according to any one of claims 1 to 6.
8. the calculation unit calculates an estimated value of an actual external quantum efficiency of each of the plurality of light-emitting elements to be tested based on the pseudo external quantum efficiency calculated in advance for a reference light-emitting element and a correction coefficient based on an actual external quantum efficiency calculated in advance for an emission test of the reference light-emitting element, from the pseudo external quantum efficiency of each of the plurality of light-emitting elements to be tested; 8. A test device according to claim 7.
9. The test apparatus according to claim 8 , wherein the calculation section uses the correction coefficient that differs depending on a manufacturing lot that includes the plurality of light emitting elements to be tested.
10. 9. The test apparatus according to claim 8, further comprising a determination unit that determines pass / fail of each of the plurality of light-emitting elements to be tested based on an estimated value of the intrinsic external quantum efficiency of each of the plurality of light-emitting elements to be tested.
11. a light emission control unit that collectively controls the plurality of light emitting elements to be tested to emit light; a light measuring unit that measures a wavelength of a composite light obtained by combining light from each of the plurality of light emitting elements to be tested as the emission wavelength related to the emission of the plurality of light emitting elements to be tested; an optical system that irradiates light from the light source incident in one direction onto the plurality of light emitting elements to be tested, and irradiates a composite light obtained by combining light from each of the plurality of light emitting elements to be tested incident in another direction onto the light measurement unit; The test apparatus of claim 7 further comprising:
12. Irradiating a light emitting device to be tested with light from a light source; measuring a photoelectric signal obtained by photoelectrically converting light irradiated by the light emitting element to be tested; calculating a pseudo external quantum efficiency that is correlated with an original external quantum efficiency of the light-emitting element to be tested based on the irradiation intensity of light irradiated from the light source to the light-emitting element to be tested, the emission wavelength of the light-emitting element to be tested, and the measured photoelectric signal of the light-emitting element to be tested; A test method comprising:
13. A test device for testing light-emitting elements, A step of irradiating a light emitting element to be tested with light from a light source; A step of measuring a photoelectric signal obtained by photoelectrically converting light irradiated by the light emitting element to be tested; calculating a pseudo external quantum efficiency having a correlation with an original external quantum efficiency of the light-emitting element to be tested based on an irradiation intensity of light irradiated from the light source to the light-emitting element to be tested, an emission wavelength related to the emission of the light-emitting element to be tested, and the measured photoelectric signal of the light-emitting element to be tested; A program that executes the following.