Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
  • G01J1/02—Details
  • G01J1/04—Optical or mechanical part supplementary adjustable parts
  • G01J1/06—Restricting the angle of incident light
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
  • G01J1/58—Photometry, e.g. photographic exposure meter using luminescence generated by light
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/42—Coupling light guides with opto-electronic elements
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/02—Structural details or components not essential to laser action
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P74/00—Testing or measuring during manufacture or treatment of wafers, substrates or devices
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 

Definitions

• This disclosure relates to an optical property inspection device.
• the optical signal emitted from the optical semiconductor element is received by the detector, the received optical signal is converted into an electrical signal, etc., and the optical axis is adjusted while checking the signal strength. Therefore, when done manually, there are issues such as the inspection results being dependent on the skill of the operator and the optical axis adjustment taking time.
• the present disclosure aims to solve the above problem by providing an optical property inspection device that can adjust the optical axis by avoiding convergence at a local optimum point and finding a global optimum point with fewer steps.
• the optical property inspection device disclosed herein comprises a detector that receives light emitted from an optical semiconductor element; a drive unit that drives and positions the measurement position of either the optical semiconductor element or the detector; and an optical axis adjustment unit that controls the drive of the drive unit and, each time positioning is performed, performs a search calculation for the position among the measurement positions at which the maximum light intensity is obtained from the optical semiconductor element based on position information indicating the measurement position obtained from the drive unit and light intensity information output from the detector, and adjusts the optical axis of the optical semiconductor element; the optical axis adjustment unit performs the search calculation using a regression method with nonlinear modeling, taking into account the amount of positional deviation caused by the drive unit.
• the optical property inspection device disclosed herein can avoid convergence at a local optimum by performing processing that takes uncertainty into account in the explanatory variables, thereby obtaining an optical property inspection device that can adjust the optical axis by finding the global optimum with fewer steps.
• 1 is a block diagram for explaining a configuration of an optical property inspection apparatus according to a first embodiment; 1 is a diagram simulating a two-dimensional distribution of the amount of light emitted from an optical semiconductor element to be inspected.
• 3A and 3B are diagrams showing the transition of search points in optical axis adjustment by full search and the transition of search points in optical axis adjustment using Gaussian process regression, respectively.
• 4A and 4B are diagrams showing the initial stage and further progress of the search for the range of twice the measured value, the predicted mean value, and the standard deviation based on the measured value in the optical axis adjustment using Gaussian process regression.
• FIG. 10 is a diagram showing a state in which a search has been completed to some extent for measured values in optical axis adjustment using Gaussian process regression and a range twice the predicted mean value and standard deviation based on the measured values.
• 4 is a flowchart for explaining the operation of the optical property inspection apparatus according to the first embodiment.
• 10 is a flowchart for explaining an operation in an optical axis adjustment step in the operation of the optical property inspection apparatus according to the first embodiment.
• FIG. 2 is a block diagram showing a hardware configuration of a part that executes arithmetic processing of the optical property inspection apparatus according to the first embodiment;
• FIG. 10 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a first modified example of the first embodiment.
• FIG. 10 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a second modified example of the first embodiment.
• FIG. 10 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a second embodiment.
• FIG. 10 is a block diagram for explaining the configuration of an optical property inspection device according to a modified example of the second embodiment.
• FIG. 11 is a block diagram for explaining a configuration at a pre-stage of an optical property inspection apparatus according to a third embodiment.
• FIG. 11 is a block diagram for explaining the configuration of the optical property inspection apparatus at a later stage according to the third embodiment.
• 10 is a flowchart for explaining the operation of the optical property inspection apparatus according to the third embodiment.
• FIG. 10 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a second modified example of the first embodiment.
• FIG. 10 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a second embodiment.
• FIG. 10 is a block diagram for explaining the configuration of an optical
• FIG. 11 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a first modified example of the third embodiment.
• FIG. 11 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a second modified example of the third embodiment.
• FIG. 10 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a fourth embodiment.
• FIG. 13 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a first modified example of the fourth embodiment.
• FIG. 13 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a second modified example of the fourth embodiment.
• FIG. 10 is a block diagram for explaining the configuration of an optical property inspection apparatus according to a fifth embodiment.
• the optical property inspection device disclosed herein can inspect modulators such as Mach-Zehnder modulators, in addition to light-emitting elements such as semiconductor lasers that emit light themselves and function as light sources.
• modulators such as Mach-Zehnder modulators
• light-emitting elements such as semiconductor lasers that emit light themselves and function as light sources.
• the following description will use an example in which a semiconductor laser is used as the object to be inspected, but if a modulator is the target, a separate light source will be provided to input an optical signal into the modulator.
• Embodiment 1. 1 to 7 are diagrams for explaining the configuration and operation of the optical property inspection device according to the first embodiment, and FIG. 1 is a block diagram illustrating the spatial arrangement of the object to be inspected and the part that detects light in order to explain the configuration of the optical property inspection device.
• Figure 2 simulates the two-dimensional distribution of the amount of light emitted from the optical semiconductor element being inspected (object under inspection) on a plane perpendicular to the optical axis, with the stronger the light intensity, the whiter the image is.
• Figure 3A shows the progression of search points during optical axis adjustment using a full search
• Figure 3B shows the progression of search points during optical axis adjustment using Gaussian process regression.
• Figures 4A, 4B, and 5 show the measured values (x), the predicted average value (solid line) based on the measured values, and the range twice the standard deviation (shaded) when adjusting the optical axis using Gaussian process regression.
• Figure 4A shows the initial stage of the search
• Figure 4B shows the state after the search has progressed further
• Figure 5 shows the state when the search has been completed to a certain extent, and is the stage at which a re-search begins in processing that takes uncertainty into account.
• Figure 6 is a flowchart explaining the overall operation of the optical property inspection device
• Figure 7 is a flowchart explaining the operation during the optical axis adjustment process.
• the optical characteristic inspection device 1 in embodiment 1 is a device that aligns (optical axis adjustment) the detector 2 that detects light with the optical axis Ao (optical axis position) relative to the output end face of an optical semiconductor element, which is the object 900, and inspects the optical characteristics of the object 900.
• an object under test fixing jig 6 is provided to position and fix the object under test 900, and an object under test operating power supply 7 is provided to operate (emit light or modulate) the object under test 900.
• the object under test fixing jig 6 may have a counterbore to match the maximum tolerance of the optical semiconductor element. By using such a design, it is possible to limit the optical axis adjustment range, and it is expected that the regression calculation will converge faster.
• a temperature control element such as a Peltier element, may also be provided.
• a vacuum suction mechanism may also be provided.
• the system also includes a detector 2 arranged with its detection surface facing the emission surface of the object under test 900, a detector drive device 3 that mechanically drives the detector 2, and a photoelectric converter 5 that converts the optical signal So output by the detector 2 into an electrical signal Se. It also includes an optical axis adjustment unit 4 that sets a search point and controls the drive of the detector drive device 3 (outputting a drive signal Scd) based on the amount of light (electrical signal Se) detected by the detector 2 and the detector 2 position information Ipd output from the detector drive device 3. It also includes an inspection control unit 8 that controls the overall operation of the optical property inspection.
• the detector 2 may be, for example, an optical fiber, a photodiode, a lensed fiber, or a bulb-tipped fiber. It is preferable to select the material of the detector 2 appropriately to match the wavelength of the light emitted from the object 900 under test.
• the detector driver 3 drives the detector 2 horizontally (perpendicular to the optical axis Ao) and in the emission direction relative to the emission surface of the object under test 900.
• a stepping motor for example, is used to drive the detector driver 3.
• the optical axis position of a laser diode or the like is about 10 ⁇ m, so it is preferable to use equipment with a finer resolution than this.
• a combination of stepping motors with different resolutions for the same direction may be used.
• the optical axis adjustment unit 4 is equipped with an optimal position search unit 41 that uses Gaussian process regression with nonlinear modeling using a kernel function to set a search point based on the electrical signal Se and position information Ipd, and a variable processing unit 42 that processes explanatory variables taking uncertainty into account. It also has a convergence determination unit 43 that determines the state of convergence in two stages: semi-convergence and complete convergence, and a re-search position setting unit 44 that sets a re-search position when semi-convergence is determined.
• an optimal position search unit 41 that uses Gaussian process regression with nonlinear modeling using a kernel function to set a search point based on the electrical signal Se and position information Ipd
• a variable processing unit 42 that processes explanatory variables taking uncertainty into account. It also has a convergence determination unit 43 that determines the state of convergence in two stages: semi-convergence and complete convergence, and a re-search position setting unit 44 that sets a re-search position when semi-convergence is determined.
• the detector 2 can be moved to coordinates that will provide a high output of light emitted from the object under test 900.
• the optimal position is searched for and set, for example, using position coordinates (position information Ipd: for example, XYZ) as explanatory variables and the light intensity (electrical signal Se) as the objective variable.
• position information Ipd for example, XYZ
• the light intensity electrical signal Se
• the detector drive device 3 may also be added with an angle adjustment function. In that case, angle information is also added to the explanatory variables.
• Gaussian process regression is generally linear, but when there are multiple peaks, such as in optical semiconductor devices, linear modeling, including Gaussian process regression, is unsuitable, and Gaussian process regression, which uses a kernel function for nonlinear modeling, is preferable.
• the optical property inspection device 1 disclosed herein overcomes the drawbacks of Gaussian process regression by, for example, adding processing (variable processing by the variable processing unit 42) that takes into account that the position information (explanatory variable) of the stepping motor is probabilistically distributed depending on the repeatability and reproducibility of the stepping motor.
• the future positional deviation of the stepping motor is thought to be strongly dependent on the current motor position, and is therefore thought to have Markov properties. Therefore, difficulties can be avoided by adding processing that takes Markov properties into account in the explanatory variables. For example, once the optical axis search has been completed to a certain extent (quasi-convergence), an algorithm can be provided that performs processing (process A) to probabilistically visit a position thought to be the optimal point several times. Alternatively, an algorithm can be provided that performs processing (process B) to vary the probability of visiting several times based on the expected value at which maximum light intensity is obtained.
• Semi-convergence is defined as the timing when it is confirmed that there is no point within the range where the search and variance calculation have converged at the current time where a higher expected value can be obtained. In other words, it is the timing when it is expected that the maximum amount of light will be obtained by re-searching.
• the timing of semi-convergence is explained using Figures 4A to 5. Note that the calculations in the figures (average predicted values) all take noise in the objective variables into account, so the function (solid line) estimated from the measurement data does not necessarily pass through the measurement points (x).
• the number of searches is still insufficient, and it is not known whether the x (explanatory variable) that will yield the maximum y (objective variable) is in the range of -3 to -2, or 1 to 2. Furthermore, the range of values that requires searching has not narrowed sufficiently. At this point, re-searching points that have already been searched is likely to be a waste of time, so quasi-convergence is not determined and re-searching is not performed.
• Process A "probabilistically visit a position considered to be the optimal point a certain number of times” or Process B: “vary the probability of visiting a certain number of times based on the expected value at which maximum light intensity is obtained", using the case shown in Figure 5.
• the object under test 900 is positioned and fixed to the object under test fixture 6 or the like (step S100). This operation may be performed manually using tweezers or the like, or automatically using a suction collet or the like based on commands from the inspection control unit 8.
• the object under test 900 is connected to the object under test operating power supply 7 for operating the object under test 900 (step S110). This connection is made by bringing a probe or the like into contact with the electrodes of the object under test 900.
• the device under test operating power supply 7 After connecting the device under test 900 to the device under test operating power supply 7, the device under test operating power supply 7 is turned on to operate the device under test 900 (step S120). This operation may also be performed manually or automatically based on commands from the inspection control unit 8. In this case, the operating conditions are not important, but it is preferable to operate the device under conditions that allow continuous light emission (or modulation) when performing optical axis adjustment.
• step S200 the light emitted from the object under test 900 is received by detector 2 while search points are set sequentially, and the optical axis adjustment process is performed (step S200).
• variable processing is first performed taking noise into account for the objective variable (step S210). Then, using Gaussian process regression with nonlinear modeling using a kernel function, variance calculations are performed based on the setting of search points and the light intensity measurement results when moving to the set search points (step S220).
• step S220 motor drive may be controlled taking into account the above-mentioned Markov property, assuming positional deviation due to inertia.
• step S230 The convergence state is determined (step S230), and if it is determined that convergence has not occurred, the process proceeds to step S220, where a re-search is performed.
• the re-search position is set (step S250) using the above-mentioned processes A and B, and the process proceeds to step S220, where a re-search is performed. If it is determined that complete convergence has occurred, the optical axis adjustment process ends.
• an optical characteristics inspection is performed (step S300: Figure 6).
• the output of the inspected object operating power supply 7 is changed depending on the inspection item, or the detector drive device 3 is driven in a pattern different from the optical axis adjustment depending on the inspection item, to inspect the optical characteristics of the inspected object 900.
• the inspected product is removed (step S400), and the inspection ends.
• a section that performs calculation processing may be configured as a single piece of hardware 400 including a processor 401 and a storage device 402, as shown in FIG. 8.
• the storage device 402 includes a volatile storage device such as random access memory and a non-volatile auxiliary storage device such as flash memory. It may also include a hard disk auxiliary storage device instead of flash memory.
• the processor 401 executes a program input from the storage device 402. In this case, the program is input to the processor 401 from the auxiliary storage device via the volatile storage device.
• the processor 401 may also output data such as calculation results to the volatile storage device of the storage device 402, or may store the data in the auxiliary storage device via the volatile storage device.
• Fig. 9 is a block diagram simulating the spatial arrangement of the object under test and the part that detects light, in order to explain the configuration of the optical property inspection device according to the first modified example.
• the internal configuration of the optical axis adjustment part will be omitted from here on, compared to Fig. 1.
• the optical property inspection device 1 is provided with an inspected object drive mechanism 6M that movably supports the inspected object 900 instead of a fixing jig.
• a signal Scs that controls the drive of the inspected object drive mechanism 6M is output from the optical axis adjustment unit 4 to the inspected object drive mechanism 6M, and position information Ips of the inspected object 900 is output from the inspected object drive mechanism 6M to the optical axis adjustment unit 4.
• the movement direction (and position) of the light source which is the object under test 900
• the movement direction (and position) of the light source is not limited to the XYZ directions of the Cartesian coordinate system, but may also be the r ⁇ directions of a spherical coordinate system.
• a detector with the function of correcting the angle of incidence such as a bulb-tipped fiber, as the detector 2.
• a global optimal solution can be obtained with a smaller amount of movement.
• the object under test 900 and the object under test drive mechanism 6M have a function for fixing the object under test 900, such as a vacuum suction mechanism, so that the emission surface of the light source (the object under test 900) accurately follows the movement. Furthermore, since the light source side is moved, it is also necessary to have a mechanism for connecting the object under test 900 and the object under test operating power supply 7, such as a probe, that moves in the same way as the object under test 900.
• a mechanism for moving the detector 2 is not shown in the first modified example, a mechanism for moving the detector 2 may be provided.
• FIG. 10 is a block diagram illustrating the spatial arrangement of an object to be inspected and a part that detects light, in order to explain the configuration of an optical property inspection device according to the second modified example.
• the optical property inspection device 1 has the same configuration as that described in the first modified example, but with a lens 2op inserted between the exit surface of the inspected object 900 and the detector 2.
• the detector 2 does not necessarily need to have the function of correcting the angle of incidence of light.
• a convex lens, a spherical-convex lens, or an aspherical lens is used for the lens 2op.
• a mechanism for moving not only the detector 2 but also the object under test 900 and the lens 2op may be provided. It is preferable to provide an appropriate movement mechanism depending on the space available in the device and the emission characteristics of the light source.
• Embodiment 2 In the second embodiment, instead of the single detector used in the first embodiment, a detector bundle is provided in which multiple detectors are bundled so that their incident surfaces are arranged in an arc shape.
• Fig. 11 is a block diagram simulating the spatial arrangement of the object to be inspected and the part that detects light, in order to explain the configuration of the optical property inspection device according to the second embodiment. Note that the operation of setting the search points is the same as in the first embodiment, and Figs. 2 to 7 described in the first embodiment are used.
• a detector bundle 2G is provided, in which multiple detectors 2 are bundled together so that their incident surfaces are arranged in an arc shape.
• the optical axis adjustment unit 4 sets a search point based on the amount of light (electrical signal SeG) detected by each detector 2 in the detector bundle 2G and the position information IpG of the detector bundle 2G output from the detector drive device 3. Then, based on the set search point, the drive of the detector drive device 3 is controlled (drive signal ScG is output).
• the detector bundle 2G is arranged so that its incident surface is arc-shaped in a plane including the optical axis Ao, and its position in the direction of the emitted light (distance from the light source) is shifted. This eliminates the need to move it in the direction of the emitted light. As a result, the detector bundle moving device 3G can be reduced by one axis compared to the detector bundle moving device 3G described in embodiment 1, and the reduction in the objective variable has the effect of allowing the regression calculation to converge faster.
• each detector 2 that makes up the detector bundle 2G is shown as being convexly offset when viewed from the light source, but it may also be concave or have another structure, and it is preferable to determine the shape appropriately depending on the characteristics of the optical semiconductor element to be measured.
• the arrangement of the incident surfaces of the detectors is not limited to an arc shape as long as the distances from the light source are different.
• an example will be described in which the incident surfaces of multiple detectors are arranged in a line so that they are at different distances from the light source.
• Figure 12 is a block diagram simulating the spatial arrangement of the object to be inspected and the part that detects light, in order to explain the configuration of the optical property inspection device according to the modified example.
• the optical property inspection device 1 may be shifted in a straight line.
• the distance of the detector bundle 2G from the light source is not changed in an arc shape with the center of the arrangement as the apex or base, but is changed monotonically, for example, from one edge to the opposite edge.
• FIGS. 13 to 15 are used to explain the configuration and operation of an optical property inspection apparatus according to the third embodiment.
• FIG. 13 is a block diagram simulating the spatial arrangement of the object to be inspected and the part that acquires the light intensity mapping when light intensity mapping information is acquired.
• FIG. 14 is a block diagram simulating the spatial arrangement of the object to be inspected and the part that detects light in a state where the equipment has been swapped after the light intensity mapping information has been acquired.
• FIG. 15 is a flowchart for explaining the operation of the optical property inspection apparatus. Note that the search point setting operation is the same as in the first embodiment, and FIGS. 2 to 6 described in the first embodiment are used.
• the optical property inspection device 1 positions a camera 2C in a preliminary step relative to the emission surface of an object under test 900 fixed to an object under test fixing jig 6.
• the sensor used for the camera 2C is a CCD (Charge-Coupled Device) image sensor, a CMOS (Complementary Metal-Oxide-Semiconductor) sensor, or the like.
• the camera 2C is supported by a camera moving device 3C that can move in at least one axial direction (the direction of the arrow in the figure) to adjust the position of the camera 2C in the emission light direction. This allows the camera 2C to acquire light intensity mapping information for the light emitted from the light source (step S130), as shown in FIG. 15.
• the equipment is rearranged to a configuration such as that shown in Figure 14 (step S140).
• the movement range of the detector 2 only needs to be searched within the range of the resolution of the camera 2C and the stepping motor from the coordinate point where the maximum light intensity is obtained on the light intensity mapping.
• accurate optical axis adjustment can be performed with fewer search points.
• the device used to acquire the light intensity mapping information is not limited to a camera.
• a phosphor is used instead of a camera.
• Fig. 16 is a block diagram simulating the spatial arrangement of an object to be inspected, a part for acquiring light intensity mapping information, and a part for detecting light, of an optical property inspection device according to the first modified example.
• a phosphor 2L may be used instead of a camera when acquiring light intensity mapping information, as shown in FIG. 16.
• a phosphor 2L corresponding to the emission wavelength of the light source is positioned at the end of the light emitted from the light source (object under inspection 900) so that it extends perpendicular to the optical axis Ao.
• a detector 2 is also positioned so that it passes through the center of the phosphor 2L.
• the light source When adjusting the optical axis, the light source is illuminated and an image of the phosphor 2L is taken by the camera 2C. This allows mapping data regarding the spread of light from the light source to be obtained based on the light emission state of the phosphor 2L, and the optical axis is adjusted at the same time.
• the light intensity distribution information acquisition (step S130) described in Figure 15 is performed in parallel in step S200, and the equipment replacement (step S140) is skipped.
• the light emission state of the phosphor 2L is used as the objective variable, and the optical axis adjustment can be completed quickly by using a statistical method such as Gaussian process regression.
• the phosphor 2L has an area that fully takes into consideration the spread of light emitted from the light source, specifically a light-receiving area of about 1 ⁇ 1 cm 2.
• the optical axis may be adjusted in a darkroom in order to detect the light-emitting state of the phosphor 2L more precisely.
• Fig. 17 is a block diagram simulating the spatial arrangement of the inspection object and the light detection unit of the optical property inspection device according to the second modified example.
• the optical axis adjustment unit 4A is configured using a computer equipped with an AD conversion board. This electrically connects the computer and photoelectric converter 5 via the AD conversion board. For example, by synchronizing the motor movement period with the timing of signal acquisition from the AD conversion board, it is possible to continuously acquire the output of the photoelectric converter 5, which converts the optical output So at a specific position into an electrical signal Se.
• This configuration makes it possible to acquire electrical signal data even while moving to a point where a statistically high output is obtained, resulting in regression using a large amount of data, which can be expected to result in rapid convergence of the regression calculation.
• Embodiment 4 In this fourth embodiment, an example will be described in which equipment for measuring the position and angle of an object under test is provided for optical axis adjustment.
• Fig. 18 is a block diagram illustrating the configuration and operation of an optical property inspection device according to the fourth embodiment, and is a model of the spatial arrangement of a part for checking the installation state of an object under test and a part for detecting light. Note that the optical axis adjustment operation is the same as in the first embodiment, and Figs. 2 to 5 and 7 described in the first embodiment, and Fig. 15 described in the third embodiment will be used.
• the optical property inspection device 1 has a detector 2 supported by a detector drive device 3 on the emission surface side of an optical semiconductor element (light source) that is an object under inspection 900.
• a single detector 2 may be used, or detectors 2 may be bundled together to increase the effective light receiving area.
• the light source which is the object under inspection 900, is imaged using camera 6C before the optical axis is adjusted.
• Image processing technology is then used to obtain the image information of the light source thus obtained, and position information such as the position information of the output end face and the tilt angle of the light source is obtained. This corresponds to replacing the light intensity distribution information acquisition (step S130) described in Figure 15 of embodiment 3 with light source position information acquisition. Furthermore, the equipment replacement (step S140) is skipped.
• the range in which the detector 2 is moved is limited based on the light source position information obtained by image processing. This configuration allows the optical axis adjustment to be completed more quickly.
• Machine learning can also be performed using the light source position information, tilt angle, and converged detector 2 (detector drive device 3) position information Ip obtained by image processing as learning data. Using machine learning makes it possible to set the initial position of the detector 2 to a point closer to the optimal point, and further limits the range in which the detector 2 is moved.
• a laser displacement meter or the like may be used in combination with a camera.
• this first modified example an example will be described in which the positional information of the light source is acquired by combining a camera and a one-dimensional laser displacement meter.
• Fig. 19 is a block diagram simulating the spatial arrangement of an object to be inspected, a part for acquiring positional information of the object to be inspected, and a part for detecting light, of the optical property inspection device according to the first modified example.
• a camera 6C and a one-dimensional laser displacement meter 6D are combined as a configuration for acquiring position information.
• the one-dimensional laser displacement meter 6D is positioned so that it irradiates the main surface with laser light from a position away along the normal to the main surface.
• the one-dimensional laser displacement meter 6D to acquire multiple points as light source height information, it is possible to acquire information on the vertical tilt of the light source.
• the prediction algorithm By inputting the light source height information and vertical tilt information into the prediction algorithm, it becomes possible to predict an initial position closer to the optimal point, and optical axis adjustment can be completed more quickly. In this case, too, the initial position can be optimized using machine learning, etc.
• FIG. 20 is a block diagram simulating the spatial arrangement of an object to be inspected in an optical property inspection device according to a second modified example, a part for acquiring positional information of the object to be inspected, and a part for detecting light.
• the optical property inspection device 1 according to the second modified example is provided with a two-dimensional laser displacement meter 6D2 as shown in Fig. 20, instead of the combination of camera 6C and one-dimensional laser displacement meter 6D in the first modified example.
• This configuration makes it possible to acquire the surface morphology of the light source, which is the object under inspection 900, and to acquire the tilt of the light source's emission surface, vertical tilt, and horizontal position information, i.e., placement information, all at once.
• the initial position of the detector 2 based on the information obtained by the two-dimensional laser displacement meter 6D2
• tilt information is available, it is also possible to reduce the search range. As a result, it is possible to reduce inspection time and calculation time.
• Embodiment 5 In the above embodiments, examples have been described in which optical axis adjustment is performed one by one on optical semiconductor elements as objects to be inspected. In this fifth embodiment, an example will be described in which multiple light sources are inspected at once as objects to be inspected.
• Figure 21 is a block diagram illustrating the configuration and operation of an optical property inspection device according to the fifth embodiment, simulating the spatial arrangement of two light sources as objects to be inspected and the light detection section. Note that the optical axis adjustment operation is the same as in the first embodiment, and Figures 2 to 7 described in the first embodiment are also used.
• the optical property inspection device 1 uses two optical semiconductor elements 900a and 900b as the object under inspection 900. Furthermore, a detector bundle 2G consisting of a bundle of multiple detectors 2 is used as the detector. For simplicity, two light sources are used, but three or more may be used.
• the power supply 7 for operating the device under test for example, alternately applies pulse signals with known periods to the optical semiconductor elements 900a and 900b, and the pulse signals are used as triggers to acquire the electrical signal SeG from the photoelectric converter 5.
• This configuration makes it possible to distinguish and acquire the optical signals from the multiple optical semiconductor elements 900a and 900b without moving the detector bundle 2G.
• detector bundle 2G Gaussian process regression using nonlinear modeling using the kernel function described above is used, and processing is performed taking uncertainty into account. For example, detector bundle 2G is first moved so that the regression calculation for one optical semiconductor element of the object under test 900 converges, and the information from the first movement is reused for the regression calculation from the second optical semiconductor element.
• the optical axis adjustment unit 4 such as the specifications of the memory and CPU (Central Processing Unit), appropriately depending on the number of optical semiconductor elements. Furthermore, multiple computers may be used if necessary.
• a bundle similar to detector bundle 2G may also be used.
• the pitch between the light sources supported by the test object fixing jig 6 falls within a range of, for example, the pitch distance of approximately ⁇ 1 mm, it is possible to provide detectors or detector bundles according to the number of light sources that match the pitch spacing between the optical semiconductor elements.
• the multiple optical semiconductor elements do not necessarily need to be arranged in a plane, but may be arranged three-dimensionally.
• the object under test 900 may be imaged and height information obtained using a camera 6C, a one-dimensional laser displacement meter 6D, a two-dimensional laser displacement meter 6D2, etc., and this information may be used to determine the movement destination of the detector bundle 2G or to limit the movement range.
• the camera 2C, phosphor 2L, etc. may be used to obtain information on the light intensity distribution of the light emitted from the light source in advance, and then the initial position may be determined.
• the field of view of the camera 2C and the area of the fluorescent surface of the phosphor 2L used in this case are determined appropriately depending on the arrangement of the multiple light sources.
• the optical property inspection device 1 disclosed herein comprises a detector 2 that receives light emitted from an optical semiconductor element (object under test 900), a drive device (detector drive device 6, detector bundle movement device 6G, camera movement device 3C, object under test drive mechanism 6M) that positions and drives the measurement position of either the optical semiconductor element (object under test 900) or the detector 2, and an optical axis adjustment unit 4 that controls the drive of the drive device and performs a search calculation for the position among the measurement positions at which the maximum light intensity is obtained from the optical semiconductor element (object under test 900) based on position information Ip indicating the measurement position obtained from the drive device and light intensity information (electrical signal Se) output from the detector 2 each time positioning is performed, and adjusts the optical axis of the optical semiconductor element (object under test 900).
• the optical axis adjustment unit 4 takes into account the amount of positional deviation caused by the drive device and performs the search calculation using a regression method using nonlinear modeling (for example, linear process regression performed nonlinear modeling using
• the influence of noise can be further reduced by providing the optical axis adjustment unit 4 with a convergence determination unit 43 that determines the convergence state of the search calculation, and a re-search position setting unit 44 that sets a re-search position when the convergence determination unit 43 determines that convergence has occurred to a certain extent.
• the re-search position setting unit 44 sets the re-search position from among multiple positions that may exhibit the maximum light intensity by weighting using variance or by allocating using random numbers, the effects of noise can be reduced more reliably.
• the detector is a detector bundle 2G consisting of detectors at different distances from the emission surface of the optical semiconductor element (object under test 900)
• the objective variable can be reduced by eliminating movement in the bundled direction (overlapping detectors 2), allowing for faster regression calculations.
• the number of calculations can be reduced, enabling faster regression calculations.
• a phosphor 2L that receives the emitted light and a camera 2C that captures the light-emitting state of the phosphor 2L may be provided, and the optical axis adjustment unit 4 may narrow the range of the search calculation based on the light emission distribution information of the phosphor 2L obtained from the camera 2C, thereby reducing the number of calculations and enabling faster regression calculations.
• the number of calculations can be reduced and regression calculations can be performed at high speed.
• the system is equipped with laser displacement meters (one-dimensional laser displacement meter 6D, two-dimensional laser displacement meter 6D2) that measure the position of the optical semiconductor element (object under test 900), and the optical axis adjustment unit 4 sets the initial position in the search calculation based on information indicating the position of the optical semiconductor element (object under test 900) obtained from the laser displacement meter, thereby reducing the number of calculations and enabling high-speed regression calculations.
• laser displacement meters one-dimensional laser displacement meter 6D, two-dimensional laser displacement meter 6D2
• the optical axis adjustment unit 4 sets the initial position in the search calculation based on information indicating the position of the optical semiconductor element (object under test 900) obtained from the laser displacement meter, thereby reducing the number of calculations and enabling high-speed regression calculations.
• the object under test 900 includes an object under test operating power supply 7 that operates multiple optical semiconductor elements 900a, 900b individually, and the optical axis adjustment unit 4 controls the object under test operating power supply 7 so that the multiple optical semiconductor elements 900a, 900b emit light at different times.
• Optical property inspection device 2: Detector, 2C: Camera, 2G: Detector bundle, 2L: Phosphor, 2op: Lens
• 3: Detector drive device 3C: Camera movement device
• 3G: Detector bundle movement device 4: Optical axis adjustment unit, 41: Optimum position search unit, 42: Variable processing unit, 43: Convergence determination unit, 44: Re-search position setting unit, 5: Photoelectric converter, 6: Inspection object fixing jig, 6C: Camera (element camera), 6D: One-dimensional laser displacement meter (laser displacement meter), 6D2: Two-dimensional laser displacement meter (laser displacement meter), 6M: Inspection object drive mechanism, 7: Inspection object operating power supply, 8: Inspection control unit, 900: Inspection object (optical semiconductor element), Ip: Position information, Scd: Drive signal, Se: Electrical signal.

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