TWM677271U - Light emitting element measuring device - Google Patents

Abstract

A light emitting element measuring device. The invention is to measure an object to be measured having a plurality of light emitting elements. The light-collecting element is disposed above the object to be tested, and is used to convert the light emitted by the plurality of light-emitting elements into a vertical light source. This is to achieve the purpose of adjusting the divergence angle of light. The light sources emitted by the plurality of light emitting elements are converted into vertical light sources. Reduce the interference of light sources received by the image sensor in the camera. In order to obtain more accurate results in subsequent calculations and more accurate measurement data..

Description

Light-emitting element measurement device

This invention relates to a measurement and inspection device, and more particularly to a mass measurement device for LEDs.

Micro-LEDs (Micro Light Emitting Diodes) are favored by manufacturers due to their advantages of high brightness, wide color gamut coverage, and high contrast. LED wafers are the core component of LEDs. In fact, the main optoelectronic parameters of LEDs, such as wavelength, brightness, and forward voltage, are largely determined by the wafer material. The processing and manufacturing of related circuit components for LEDs are all completed on the wafer. Therefore, wafer technology and equipment are key to wafer manufacturing technology. After processing, LED wafers need to be measured to inspect and accept the products. Inspection is used to visually determine whether the processed LED wafers (chips) are qualified, thus requiring appropriate inspection devices and methods.

Existing inspection techniques include using Charge Coupled Device (CCD) cameras for light collection. The key feature of this method is that it uses a CCD image sensor to capture the light emitted by the light-emitting element, thus determining the quality of the element. This measurement method can collect light from multiple LED chips and is fast, but due to the large divergence angle of LED chips, its accuracy is low, requiring algorithms to reduce errors.

Please refer to Figure 1, which is a schematic diagram of a conventional light-emitting element measurement device. The measurement device includes at least a stage 10, an imaging lens 20, a camera 30, and a computing system 40. In practice, an object under test 50 having a plurality of light-emitting elements is placed on the stage 10, which is movable in the XY direction. The object under test 50 is energized by an excitation light source to make its light-emitting elements emit light. The light emitted by the light-emitting elements on the object under test 50 passes through the imaging lens 20 to the camera 30. The imaging lens 20 images the fluorescent light emitted by the object under test 50 and guides the fluorescent light to the CCD image sensor in the camera 30 to capture the light emitted from the light-emitting elements on the object under test 50. Finally, the pixel information of the camera 30 is transmitted to the calculation system 40. The calculation system 40 uses a computer to perform calculations on the fluorescent image of the light-emitting element on the test object 50 originally acquired by the camera 30 to determine whether it is good or bad, and correspondingly determines the good or bad of each light-emitting element on the test object 50.

This CCD camera shooting method utilizes LED wafers with multiple LED chips for light collection, resulting in fast measurement speed. However, due to the large divergence angle of the LED chips, the accuracy of this measurement method is reduced, or a larger interval is required between the measured chips. Therefore, in practice, the large emission angle of the LED wafer chips causes mutual light interference, resulting in severe interference with the light intensity received by the sensing elements inside the camera 30, making it difficult to obtain more accurate results in subsequent calculations.

The purpose of this invention is to use a focusing element to adjust the light divergence angle, reduce the problem of light interference caused by a large light emission angle, reduce the interference of light source received by the image sensor inside the camera, so as to obtain more accurate results and more accurate measurement data in subsequent calculations.

To achieve the above objectives, this invention discloses a light-emitting element measurement device for measuring an object under test having a plurality of light-emitting elements. The device includes: a stage for fixing the object under test, wherein the plurality of light-emitting elements on the object under test emit light after being energized by an excitation light source; a focusing element disposed above the object under test for converting the light emitted by the plurality of light-emitting elements into a vertical light source; an imaging lens disposed above the focusing element for imaging the vertical light source; an image sensor internally provided in a camera for sensing and capturing the fluorescent light captured by the imaging lens; and a calculation system executed by a computer to perform calculations on the fluorescent image acquired by the camera to determine its quality, and to determine the quality of the plurality of light-emitting elements accordingly.

The light-concentrating element is composed of a plurality of microlenses, which correspond to a plurality of light-emitting elements, converting the light emitted by the plurality of light-emitting elements into a vertical light source.

The light-concentrating element is composed of liquid crystal lenses. By changing the liquid crystal angle corresponding to the plurality of light-emitting element regions through different electrical signals, the light divergence angle is reduced, so that the plurality of light-emitting elements convert the emitted light source into a vertical light source.

The focusing element is composed of a plurality of fiber beam collimators, which correspond to the plurality of light-emitting elements and convert the light emitted by the plurality of light-emitting elements into a vertical light source.

The image sensor is either a charge-coupled device (CCD) sensor with a two-dimensional pixel array or a complementary metal-oxide-semiconductor (CMOS) sensor with a two-dimensional pixel array.

This invention utilizes a focusing element to convert the light emitted by the plurality of light-emitting elements into a vertical light source. The image received by the back-end image sensor can effectively distinguish the source of different chips (light-emitting elements), reducing the interference of overlapping light divergence angles between adjacent light-emitting elements. This reduces the light source interference received by the image sensor in the camera, resulting in more accurate results and measurement data in the subsequent calculation system. This data is then used for product acceptance, allowing for inspection and observation to determine whether the chips (light-emitting elements) on the processed LED wafers are qualified.

To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention, under the premise of equivalent changes and modifications, should fall within the scope of protection of the present invention.

Please refer to Figure 2, which is a schematic diagram of the light-emitting element measurement device of this invention. The light-emitting element measurement device includes at least a stage 100, an imaging lens 200, a camera 300, a calculation system and a focusing element 600.

In practice, the light-emitting element measurement device of this invention measures a test object 500 (as shown in Figure 3) having one of a plurality of light-emitting elements 510; the test object 500 is a semiconductor device having a plurality of light-emitting elements 510 formed on a wafer. The light-emitting element 510 is, for example, an LED (Light Emitting Diode), a micro LED, a μLED, an SLD (Super Luminescent Diode) element, a laser element, or other such chip.

The stage 100 holds the object under test 500 in place and controls the object under test 500 along the XY direction (front and back, left and right) so that the test area on the surface of the object under test 500 corresponds to the imaging lens 200. The plurality of light-emitting elements 510 on the test area emit light after being energized by an excitation light source. In practice, light with wavelengths that excite the light-emitting elements 510 can be generated by laser light or the like.

The focusing element 600 is disposed above the object under test 500 to convert the light emitted by the plurality of light-emitting elements 510 into a vertical light source, thereby adjusting the light divergence angle. By modifying the light divergence angle between the light-emitting elements 510 in the test area on the surface of the object under test 500, the overlapping and interference phenomenon of light divergence angles between adjacent dies on the wafer is reduced, thus reducing the problem of light interference during the measurement process.

In practical application, the focusing element 600 is a lens element 600 composed of a plurality of micro lenses 611 (as shown in Figure 3). The plurality of micro lenses 611 correspond to the plurality of light-emitting elements 510, and the light source emitted by the corresponding light-emitting element 510 is converted into a vertical light source through the micro lenses 611.

In practical applications, the light-concentrating element 600 is composed of a liquid crystal lens 620 (as shown in Figure 4). When energized, a vertical electric field that varies linearly along the aperture of the lens is generated inside the liquid crystal layer, forming a centrally symmetrical gradient refractive index distribution within the liquid crystal layer. This allows the liquid crystal layer to focus incident light. By changing the liquid crystal angle corresponding to the region of the plurality of light-emitting elements 510 through different electrical signals, the light divergence angle is reduced, and the plurality of light-emitting elements 510 convert the emitted light source into a vertical light source.

In practical application, the focusing element 600 is composed of a plurality of fiber beam collimators 630, which can form a fiber beam collimator matrix. The plurality of fiber beam collimators 630 correspond to the plurality of light-emitting elements 510 and are matched with each other to convert the light source emitted by the plurality of light-emitting elements 510 into a vertical light source.

The imaging lens 200 is disposed above the light-collecting element 600 to image the vertical light source and guide the light emitted by the light-emitting element 510 to the camera 300; the camera 300 is provided with an image sensor for sensing and capturing the fluorescent light imaged by the imaging lens 200; the image sensor in the camera 300 may be, but is not limited to, a complementary metal-oxide-semiconductor (CMOS) sensor or a charge-coupled device (CCD) array sensor with a two-dimensional pixel array.

The calculation system 400 is executed by a computer to perform calculations on the fluorescent image acquired by the camera 300 to determine its quality, and to determine the quality of the light-emitting element 510 in the test area on the surface of the object under test 500. The aforementioned computer can be, but is not limited to, a personal computer, a cloud server, or a smart device (smartphone, tablet terminal), etc. The calculation system 400 utilizes the CPU of the computer system to execute programs stored in memory to calculate the optical feature value of each pixel in the entire image of the camera 300, thereby obtaining the individual values of each chip in the image range. This faster measurement of the individual values of multiple chips can improve production efficiency and reduce the defect rate of subsequent processes.

The above description is merely a specific embodiment of this application and does not constitute any limitation on this application. Although this application has disclosed specific embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall still fall within the scope of the technical solution of this application.

10, 100: Stage; 20, 200: Imaging Lens; 30, 300: Camera; 40, 400: Calculation System; 50, 500: Object Under Test; 510: Light Emitting Element; 600: Condensing Element; 610: Lens Assembly; 611: Miniature Lens; 620: Liquid Crystal Lens; 630: Fiber Optic Beam Collimator

Figure 1 is a schematic diagram of a conventional light-emitting element measuring device. Figure 2 is a schematic diagram of the light-emitting element measuring device of this invention. Figure 3 is a schematic diagram of an embodiment of the light-concentrating element of this invention (first embodiment). Figure 4 is a schematic diagram of an embodiment of the light-concentrating element of this invention (second embodiment). Figure 5 is a schematic diagram of an embodiment of the light-concentrating element of this invention (third embodiment).

100: Platform

200: Imaging Lens

300: Camera

400: Calculation System

500: Item to be tested

600: Concentrating element

Claims (6)

A light-emitting element measurement device is used to measure an object under test having a plurality of light-emitting elements. The device includes: a stage for fixing the object under test, wherein the plurality of light-emitting elements on the object under test emit light when energized by an excitation light source; a focusing element disposed above the object under test for converting the light emitted by the plurality of light-emitting elements into a vertical light source; an imaging lens disposed above the focusing element for imaging the vertical light source; a camera having an image sensor for sensing and capturing the fluorescent light captured by the imaging lens; and a calculation system executed by a computer, wherein the camera transmits the acquired fluorescent image to the calculation system, and the calculation system performs calculations to determine whether the images are good or bad, corresponding to the good or bad condition of the plurality of light-emitting elements. The light-emitting element measuring device as described in claim 1, wherein the light-concentrating element is composed of a plurality of microlenses, the plurality of microlenses corresponding to the plurality of light-emitting elements, converting the light emitted by the plurality of light-emitting elements into a vertical light source. The light-emitting element measuring device as described in claim 1, wherein the light-concentrating element is composed of liquid crystal lenses, and the liquid crystal angle corresponding to the plurality of light-emitting element regions is changed by different electrical signals to achieve the effect of reducing the light divergence angle, so that the plurality of light-emitting elements convert the emitted light source into a vertical light source. The light-emitting element measuring device as described in claim 1, wherein the focusing element is composed of a plurality of fiber beam collimators, the plurality of fiber beam collimators corresponding to the plurality of light-emitting elements, converting the light source emitted by the plurality of light-emitting elements into a vertical light source. The light-emitting element measuring device as described in claim 1, wherein the image sensor is a charge-coupled device (CCD) sensor having a two-dimensional pixel array. The light-emitting element measurement device as described in claim 1, wherein the image sensor is a complementary metal-oxide-semiconductor (CMOS) sensor having a two-dimensional pixel array.