TW202122810A - Light emitting element detecting method and equipment - Google Patents

Abstract

A light emitting element detecting method and a light emitting element detecting equipment adapted for the method are discloses. The method includes the steps of generating a first control signal to open a shutter of an image capturing device which captures an image toward a light outlet of a light emitting element, generating a pulse signal to light up the light emitting element, generating a second control signal to close the shutter of the image capturing device and obtaining a detection image, and determining the light emitting status of the light outlet of the light emitting element according to the detection image. As a result, the present invention can accurately detect whether the light outlet of the light emitting element has the problem of emitting no light or flashing.

Description

Light-emitting element detection method and equipment

The present invention is related to the detection technology of light-emitting elements (such as laser chips), and particularly relates to a light-emitting element detection method and equipment for detecting whether the light-emitting port of the light-emitting element emits light or flashes.

Conventional laser chip testing is done after the wafer is made with a large number of connected chips, using one of the probe card probes or other probe devices (such as edge sensors) of the one-point measuring machine ) The probe touches the chip to make the chip emit light, and at the same time, it receives the light emitted by the chip to detect its optical characteristics. The light emission of the laser chip, especially the vertical-cavity surface-emitting laser array (Vertical-Cavity Surface-Emitting Laser Array; referred to as VCSEL) chip, is caused by a plurality of irregular arrangements distributed on one surface of the laser chip. The light outlets glow at the same time.

However, when a VCSEL chip is energized and emits light, one or some of its light outlets may not emit light, or even if there is light, it will flicker. That is, the light outlets are not always in a constant light state, but sometimes It will shine and sometimes it will not shine. When a VCSEL chip has problems such as non-lighting or flickering, the light output port exceeds a certain number or proportion, it is necessary to determine that the chip is a defective product. Therefore, how to accurately detect whether the light-emitting port of the light-emitting element has non-lighting or flickering problems, It is an important inspection item for VCSEL chips.

The main purpose of the present invention is to provide a light-emitting element detection method and equipment, which can accurately detect whether the light-emitting port of the light-emitting element does not emit light or flickers.

In order to achieve the above-mentioned object, the light-emitting element detection method provided by the present invention includes the following steps: a) Generate a first control signal to open the shutter of an image capture device that captures images toward at least one light-emitting port of a light-emitting element; b) Generate a pulse signal to light up the light-emitting element; c) generating a second control signal to close the shutter of the image capturing device and obtain a detection image; and d) Judging the light-emitting condition of the light-emitting port of the light-emitting element based on the detected image.

In order to achieve the above-mentioned object, the light-emitting element detection equipment provided by the present invention includes an image capturing device for capturing images toward at least one light-emitting port of a light-emitting element, and a probe mold electrically connected to the light-emitting element Group, and a control module electrically connected to the image capture device and the probe module, the control module periodically sends a first control signal to the image capture device to open its shutter and send a The second control signal is sent to the image capturing device to close its shutter, and periodically sends a pulse signal to the probe module to light up the light-emitting element, and the time point of sending the pulse signal is when the first Between the time point of the control signal and the time point of transmitting the second control signal.

In this way, the present invention can ensure that the image capturing device captures the image when the light-emitting element is lit, so as to accurately determine the light-emitting condition of the light-emitting port of the light-emitting element. For example, when the detected image shows that a light outlet is not emitting light or its light intensity is not within a predetermined standard light intensity range or the error with a predetermined standard light intensity is greater than a predetermined interval, the light exit port can be recorded as having light. The light outlet of the problem. The present invention can also obtain a plurality of detection images by repeating steps a), b) and c) multiple times, and compare the detection images. When a certain light outlet shows normal light emission in part of the detection images, but When the light outlet is judged to be problematic in other detected images, it can be judged that the light outlet has a flickering problem.

The detailed structure, characteristics, assembly or use of the light-emitting element detection method and equipment provided by the present invention will be described in the detailed description of the subsequent embodiments. However, those with ordinary knowledge in the field of the present invention should be able to understand that the detailed description and the specific embodiments listed for implementing the present invention are only used to illustrate the present invention, and are not intended to limit the scope of the patent application of the present invention.

Please refer to FIG. 1. The light-emitting element detection device 10 and the light-emitting element detection method (shown in FIG. 2) provided by a preferred embodiment of the present invention are used to perform light-emitting detection on a light-emitting element 20, and are particularly suitable for detecting such For light-emitting elements such as VCSEL chips, in fact, VCSEL chips are inspected on the wafer before being cut. In order to simplify the diagram and facilitate the description, only a light-emitting element 20 is schematically drawn in FIG. 1 to show A VCSEL chip, as shown in FIG. 3, the light emitting element 20 (VCSEL chip) has a plurality of light emitting ports 22.

As shown in FIG. 1, the light-emitting element inspection equipment 10 includes an image capture device 11, an optical adjustment module 12 coupled to the image capture device 11, and an objective lens 13 coupled to the optical adjustment module 12 , A probe module 14, a control module 15 electrically connected to the image capturing device 11 and the probe module 14, and a storage device 16 electrically connected to the image capturing device 11.

The image capturing device 11 may be a camera or video camera using a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) as a photosensitive element, and the image capture The device 11 captures images toward the light exit 22 of the light emitting element 20 through the optical adjustment module 12 and the objective lens 13.

In this embodiment, the optical adjustment module 12 includes an optical tunnel 122 (optical tunnel; OT) for guiding light, and a filter unit 124 for filtering light. Two ends of the optical tunnel 122 They are respectively coupled to the image capturing device 11 and the filter unit 124, and the filter unit 124 is coupled to the objective lens 13. The filter unit 124 can be provided with a plurality of filter elements (not shown in the figure) with different filtering effects, and a turntable (not shown in the figure) that rotates the appropriate filter element to the detection light path by receiving a control signal ). This part is relatively unrelated to the technical features of the present invention, and the applicant is not allowed to describe it in detail here.

The probe module 14 includes a plurality of probes. In this embodiment, the probe module 14 uses a positive electrode probe 141 and a negative electrode probe 142 to touch the positive and negative electrodes of the light-emitting element 20, respectively. The conductive contacts (not shown in the figure) are electrically connected to the light-emitting element 20. Alternatively, the present invention is also applicable to a light-emitting element with a conductive contact on the front and a planar electrode on the back, and the probe module uses a probe to touch the conductive contact on the front of the light-emitting element. The control module 15 may be a source measurement unit (SMU), which is used to accurately output the power required for the light-emitting element 20 to emit light, and transmit it to the light-emitting element through the probe module 14 20, and then drive the light-emitting element 20 to emit light.

Please refer to the drawings. The light-emitting element detection method of the present invention includes the following steps:

a) A first control signal 31 (as shown in FIG. 4) is generated to open the shutter of the image capturing device 11, as shown in step S1 in FIG. 2.

b) Generate a pulse signal 32 (as shown in FIG. 4) to light up the light-emitting element 20, as shown in step S2 in FIG. 2.

c) Generate a second control signal 33 (as shown in FIG. 4) to close the shutter of the image capturing device 11 and obtain a detection image 34, as shown in step S3 in FIG. 2.

d) Judging the light-emitting condition of the light-emitting port 22 of the light-emitting element 20 by the detection image 34, as shown in steps S4 and S5 in FIG. 2.

In this embodiment, the control module 15 periodically generates the first and second control signals 31, 33 that constitute the square wave in the upper half of FIG. 4 and sends them to the image capturing device 11. The image capturing The device 11 receives the first control signal 31 sent by the control module 15 at a first time point T1 and opens its shutter, so that the photosensitive element starts to receive light. The image capturing device 11 receives the control module 15 at a first time. The second control signal 33 sent at the two time point T2 closes its shutter, so that the photosensitive element is no longer sensitive. The image capture device 11 processes the light signal sensed by the photosensitive element to form a detection image corresponding to the photosensitive state. 34 (as shown in FIG. 5), and the detected image 34 is transmitted to the storage device 16 for storage.

In addition, the control module 15 also periodically generates a pulse signal 32 constituting the square wave in the lower half of FIG. 4 and transmits it to the probe module 14, and transmits the pulse signal 32 at the third time point T3 (each The time of the pulse signal 32 is very short, so it is only represented by a time point) is between the first time point T1 when the first control signal 31 is transmitted and the second time point T2 when the second control signal 33 is transmitted, the light emitting element 20 receives The pulse signal 32 is energized to emit light at each light outlet 22. In other words, the time point when the light-emitting element 20 emits light is during the opening of the shutter of the image capturing device 11, which ensures that the detection image 34 captured by the image capturing device 11 will show the light emitted by the light-emitting port 22 of the light-emitting element 20 Circumstances, for the subsequent step d) for judgment processing.

In detail, when the light emitting element 20 receives the pulse signal 32 and is energized, the light emitted from the light outlet 22 of the light emitting element 20 respectively passes through the objective lens 13, the filter element of the filter unit 124, and the optical channel 122 and is then received by the image capturing device 11 After receiving, the image capturing device 11 presents the light from the light exit ports 22 that are indistinguishable by the naked eye on the detection image 34. As shown in FIG. 5, the detection image 34 shows a plurality of light exit ports 22 respectively. Light spots 342. In fact, most of the light spots described in the present invention are in irregular shapes. However, in order to simplify the drawings and facilitate the description, the light spots in the drawings of the present invention are all drawn as circles.

In step d), the method of judging the light-emitting condition can firstly measure the light intensity of the light-emitting port 22 of the light-emitting element 20 by the detection image 34, and then judge the light-emitting condition. In detail, image processing software can be used to perform post-processing on each pixel (pixel) of the detection image 34, and the relative light intensity of each pixel of the detection image 34 can be measured, and then the light spot 342 occupied The relative light intensity of each pixel is calculated as its average value, and the relative light intensity of each light spot 342 is obtained, which can represent the light intensity of each light outlet 22. For example, the light spot 342A in FIG. 6 occupies nine pixels 344 in the detection image 34, and the relative light intensity of the nine pixels 344 is calculated to obtain the relative light intensity of the light spot 342A. , And the relative light intensity of the light spot 342A can represent the luminous intensity of the light outlet 22A (as shown in FIG. 3) corresponding to the light spot 342A. In order to simplify the drawing, in the drawing of the present invention, only nine pixels 344 of the detection image 34 are schematically drawn with imaginary lines for illustration.

It is worth mentioning that the relative light intensity mentioned in the present invention is a value calculated by image processing software that can represent the luminous intensity. The relative light intensity measured by the image of a standard light source is compared with the actual luminous intensity of the standard light source. Intensity physical quantity (for example, watt (W)), which can be used to convert the measured relative light intensity of the light spot 342 into the actual light intensity of the corresponding light outlet 22 (for example, the unit is watt/steradian). /Cm² (W/Sr/cm ² )).

Furthermore, in the step d), it can be judged whether the light intensity of each light outlet 22 is within a predetermined standard light intensity range from the light intensity measured in the foregoing process, or judge the light intensity of each light outlet 22 Is the error with a predetermined standard light intensity greater than a predetermined interval? If the light intensity of a certain light outlet 22 is continuously tested, the light intensity is not within the set standard light intensity range or the luminance error with the standard light intensity is greater than The predetermined interval can be recorded as a problematic light exit 22. When all the light exit ports 22 of the light emitting element 20 are not within the standard light intensity range or the error with the standard light intensity is greater than the predetermined interval, the number of light exit ports 22 exceeds a reference value, that is, the number of problematic light exit ports 22 exceeds With the reference value, it can be determined that the light-emitting element 20 does not meet the specifications, or the light-emitting element 20 can be classified as a certain usable level.

The light-emitting element detection method of the present invention can further repeat the aforementioned steps a), b) and c) multiple times to obtain a plurality of detection images 34, and the aforementioned control module 15 periodically transmits the first and second control signals 31 , 33 and the pulse signal 32 can be achieved, and the light emitting condition of each light outlet 22 of the light emitting element 20 in each of the detection images 34 can be determined in the aforementioned manner. This not only improves the detection accuracy, but also improves the detection accuracy. The detected images 34 are compared with each other to determine whether each of the light outlets 22 is flickering, that is, when a certain light outlet 22 shows normal light emission in some of the detected images 34 but there is light in other detected images 34 If the intensity is insufficient or no light is emitted, it can be judged that the light exit 22 has a flicker phenomenon. In order to accurately detect whether the optical port 22 has problems such as non-lighting, insufficient light intensity or flickering, the foregoing repeat steps a), b) and c) are preferably more than ten times, so as to obtain more than ten detected images 34 For comparison. In addition, as shown in FIG. 4, each time the light-emitting element 20 is lit by the pulse signal 32, it emits light for a light-emitting time T4, and every two light-emitting time T4 is separated by a cooling time T5. The cooling time T5 is preferably set to The light-emitting time T4 is more than one hundred times (Figure 4 is only schematically drawn, and not according to this scale), so that the light-emitting element 20 heated by light-emitting has enough time to cool down before performing the next light-emitting, avoiding the influence of heat , In order to improve the accuracy of detection.

In summary, the present invention controls the opening and closing of the shutter of the image capturing device 11 by providing the first and second control signals 31, 33, and between the time points when the first and second control signals 31, 33 are provided A pulse signal 32 is also provided to light up the light-emitting element 20 under test, so as to ensure that the image capturing device 11 captures the image when the light-emitting element 20 under test is lit, so as to accurately determine the light-emitting element 20 The light-emitting condition of the light-emitting port 22 can be used to detect the light-emitting port 22 with non-lighting, flickering, etc., and determine whether the light-emitting element 20 meets the specifications, or classify the light-emitting element 20 into a certain usable level.

Finally, it must be explained again that the constituent elements disclosed in the previously disclosed embodiments of the present invention are only examples and are not intended to limit the scope of the case. Alternatives or changes to other equivalent elements should also be the scope of the patent application for this case. Covered.

10: Light-emitting element testing equipment 11: Image capture device 12: Optical adjustment module 122: optical channel 124: filter unit 13: Objective 14: Probe module 141: Positive electrode probe 142: Negative electrode probe 15: Control module 16: storage device 20: Light-emitting element 22, 22A: light outlet 31: The first control signal 32: Pulse signal 33: The second control signal 34: Detect image 342,342A: light spot 344: pixels S1~S5: steps T1: the first point in time T2: second time point T3: The third time point T4: Luminous time T5: Cooling time

FIG. 1 is a schematic diagram of a light-emitting element detection device and a light-emitting element provided by a preferred embodiment of the present invention. FIG. 2 is a flowchart of the light-emitting element detection method provided by the preferred embodiment of the present invention. Fig. 3 is a schematic diagram of the light-emitting element. 4 is a schematic diagram of the waveform of the signal used in the preferred embodiment of the present invention. FIG. 5 is a schematic diagram of a detection image in the light-emitting element detection method provided by the preferred embodiment of the present invention. Fig. 6 is an enlarged view of part A of Fig. 5.

S1~S5: steps

Claims (11)

A method for detecting light-emitting elements, the steps of which include: a) Generate a first control signal to open the shutter of an image capture device that captures images toward at least one light-emitting port of a light-emitting element; b) Generate a pulse signal to light up the light-emitting element; c) Generate a second control signal to close the shutter of the image capture device and obtain a detection image; and d) Judging the light-emitting condition of the light-emitting port of the light-emitting element based on the detected image. The light-emitting element detection method according to claim 1, repeating steps a), b) and c) multiple times to obtain a plurality of the detection images, and in step d) the light-emitting port of the light-emitting element is determined by each detection image The luminous situation. The method for detecting a light-emitting element according to claim 2, wherein the step d) comprises comparing the detected images to determine whether the light-emitting port of the light-emitting element is flickering. The light-emitting element inspection method according to claim 3, wherein the plurality of times is ten times or more. The light-emitting element detection method according to claim 2, wherein each time the light-emitting element is lit by the pulse signal, it emits light for a light-emitting time, and every two light-emitting time is separated by a cooling time, and the cooling time is a part of the light-emitting time. More than a hundred times. The method for detecting a light-emitting element according to any one of claims 1 to 5, wherein the step d) comprises measuring the light intensity of the light-emitting port of the light-emitting element by the detection image. The light-emitting element detection method according to claim 6, wherein the step d) further comprises determining whether the light intensity of the light-emitting port of the light-emitting element is within a standard light intensity range or judging whether the light intensity of the light-emitting port of the light-emitting element is Whether the error of a standard light intensity is greater than a predetermined interval. The light-emitting element detection method according to claim 7, wherein the light-emitting element includes a plurality of the light-emitting ports, and when the light-emitting element is not within the standard light intensity range or the error with the standard light intensity is greater than the light-emitting port in the predetermined interval If the quantity exceeds a reference value, it is determined that the light-emitting element does not meet the specifications. A light-emitting element detection equipment, including: An image capturing device for capturing images toward at least one light-emitting port of a light-emitting element; A probe module for electrically connecting with the light-emitting element; and A control module is electrically connected to the image capture device and the probe module. The control module periodically sends a first control signal to the image capture device to open its shutter and send a second The control signal is sent to the image capture device to close its shutter, and a pulse signal is periodically sent to the probe module to light up the light-emitting element, and the time point of sending the pulse signal is when the first control signal is sent Between the time point and the time point when the second control signal is transmitted. The light-emitting element testing equipment as described in claim 9, further comprising: An optical adjustment module coupled to the image capturing device; and An objective lens coupled with the optical adjustment module; Wherein, the image capturing device captures images toward the light-emitting port of the light-emitting element through the optical adjustment module and the objective lens. The light-emitting element detection equipment according to claim 9, further comprising: a storage device electrically connected to the image capture device for storing the image captured by the image capture device.

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