Target object surface nondestructive measurement device

Abstract

The utility model relates to a nondestructive measurement device for the surface of a target object. The device comprises a first light source, a lens, a linear dichroscope, a first image sensor and a second image sensor, the first light source emits first exciting light to a target object with a photoluminescence material, and the characteristic that the transmittance of the linear dichroscope is increased along with the increase of the wavelength is utilized; image processing is carried out on a first gray level image of target object detection light which is obtained by a first image sensor and penetrates through a linear dichroscope and a second gray level image of target object detection light which is obtained by a second image sensor and reflects the linear dichroscope, a mass center spectrum of each point of a target object is obtained, and then surface information of the target object is obtained. Through the non-contact detection device, physical damage to the electrode and the surface of the Micro LED chip caused by the probe can be avoided, so that wafer-level Micro LEDs can be detected so as to intercept dead pixels, and the yield of Micro LED display screens is improved.

Description

Technical Field

[0001] The present application relates to the field of Micro-LED display technology, and in particular to a device for non-destructive measurement of the surface of a target object. Background Art

[0002] With the continuous advancement of the manufacturing process of micro gallium nitride (GaN) light emitting diodes (LEDs), GaN-based micro light emitting diode (MicroLED) displays, which have the advantages of low power consumption, long life, small size and high reliability, are expected to become the next generation of display technology and shine in the fields of near-eye display, large-size high-definition display devices, flexible screens, etc.

[0003] Among the many technical aspects of Micro LED displays, wafer-level Micro LED chip inspection is a key step in preventing bad pixels, improving display yields, and reducing overall manufacturing costs. Existing inspection methods for large arrays of wafer-level Micro LED chips (on the order of millions) and small sizes (<50μm) suffer from low efficiency and high costs. Therefore, the development trend of wafer-level Micro LED inspection technology is to improve inspection efficiency, enhance inspection accuracy, and reduce inspection costs. Utility Model Content

[0004] Based on this, it is necessary to provide a non-destructive measurement device for the surface of a target object that can improve detection efficiency and reduce detection costs in response to the above technical problems.

[0005] In a first aspect, the present application provides a device for non-destructive measurement of a target surface, comprising:

[0006] A first light source is used to emit a first excitation light to a target object; the target object includes a photoluminescent material;

[0007] A lens receives and adjusts the target detection light excited by the first excitation light;

[0008] a linear dichroic mirror that transmits at least a portion of the target detection light and reflects at least a portion of the target detection light; wherein the transmittance of the linear dichroic mirror increases with increasing wavelength and the reflectance decreases with decreasing wavelength;

[0009] a first image sensor, arranged in a transmission light path of the linear dichroic mirror, to obtain a first grayscale image of the target detection light transmitted by the linear dichroic mirror; and

[0010] a second image sensor disposed on a reflection light path of the linear dichroic mirror to obtain a second grayscale image of the target detection light reflected by the linear dichroic mirror;

[0011] The centroid spectrum of each point of the target object is obtained by performing image processing on the first grayscale image and the second grayscale image; and the surface information of the target object is obtained based on the centroid spectrum of each point of the target object.

[0012] In one embodiment, the target surface non-destructive measurement device further includes: a light homogenizer, which is located at the emission end of the first light source and is used to receive the first excitation light emitted by the first light source and perform light homogenization on the light intensity of the first excitation light.

[0013] In one embodiment, the light homogenizer is a homogenizing optical fiber, and the input end of the homogenizing optical fiber has multiple interfaces capable of receiving the first excitation light of different wavelengths.

[0014] In one embodiment, the target surface non-destructive measurement device further includes: a collimator, which is located at the output end of the homogenizer and is used to receive the homogenized first excitation light and adjust the emission angle of the first excitation light to be perpendicular to the surface of the target object.

[0015] In one embodiment, the target surface non-destructive measurement device further includes: a second beam splitter prism disposed between the lens and the linear dichroic mirror, capable of deflecting the first excitation light.

[0016] In one embodiment, the target surface non-destructive measurement device further includes: a first filter located in the optical path between the lens and the linear dichroic mirror, configured to filter out the excitation light reflected by the target and transmit the detection light through the target.

[0017] In one embodiment, the target surface non-destructive measurement device further includes:

[0018] An aperture, located at the emission end of the first light source, capable of blocking part of the light spot of the first excitation light to obtain the second excitation light;

[0019] a lens, opposite to the aperture, receiving the second excitation light, collimating the second excitation light, thereby converting divergent light into parallel light; and the lens also receiving the third excitation light and converging the third excitation light; wherein the third excitation light is obtained by reflecting the second excitation light from the target object;

[0020] The second filter is located in the optical path between the lens and the lens, and is used to filter out the target detection light and transmit the third excitation light;

[0021] The third image sensor receives the third excitation light and obtains a spot image of the third excitation light; obtains the defocus amount of the lens according to the spot image of the third excitation light, and adjusts the distance between the lens and the target object based on the defocus amount.

[0022] In one embodiment, the target surface non-destructive measurement device further includes:

[0023] a second light source for emitting a fourth excitation light to the target object; the wavelength of the fourth excitation light is greater than the wavelength of the first excitation light;

[0024] an aperture, located at the emission end of the second light source, capable of blocking part of the light spot of the fourth excitation light to obtain the fifth excitation light;

[0025] a lens, opposite to the aperture, receiving the fifth excitation light, collimating the fifth excitation light, thereby converting divergent light into parallel light; and the lens also receiving the sixth excitation light and converging the sixth excitation light; wherein the sixth excitation light is obtained by reflecting the fifth excitation light from the target object;

[0026] a second filter, located in the optical path between the lens and the lens, for filtering out the target detection light and transmitting the fifth excitation light and the sixth excitation light;

[0027] The third image sensor receives the sixth excitation light and obtains a spot image of the sixth excitation light; obtains the defocus amount of the lens according to the spot image of the sixth excitation light, and adjusts the distance between the lens and the target object based on the defocus amount.

[0028] In one embodiment, the target surface non-destructive measurement device further includes: a first beam splitter prism disposed between the aperture and the lens, capable of deflecting light converged by the lens to the third image sensor.

[0029] In one embodiment, the target surface non-destructive measurement device further includes: a third beam splitter prism, arranged in the optical path between the second filter and the lens, capable of deflecting the fifth excitation light to the lens and deflecting the sixth excitation light to the second filter.

[0030] The above-mentioned nondestructive surface measurement device emits excitation light to a target comprising a photoluminescent material. A linear dichroic mirror is positioned in the optical path of the target's probe light, utilizing the characteristics of the linear dichroic mirror: its transmittance increases with increasing wavelength and its reflectance decreases with decreasing wavelength. The linear dichroic mirror is positioned in the optical path of the target's probe light. A first image sensor is positioned in the transmission optical path of the linear dichroic mirror to obtain a first grayscale image of the target's probe light transmitted by the linear dichroic mirror. A second image sensor is positioned in the reflection optical path of the linear dichroic mirror to obtain a second grayscale image of the target's probe light reflected by the linear dichroic mirror. Image processing is performed on the first and second grayscale images to obtain a centroid spectrum at each point on the target. Surface information of the target is then obtained based on the centroid spectrum at each point on the target. This nondestructive testing of the target allows surface information of the target comprising the photoluminescent material to be obtained. Furthermore, surface defect information of the target comprising the photoluminescent material can be obtained based on this nondestructive testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 Schematic diagram of the optical path of a device for non-destructive measurement of a target surface in one embodiment;

[0033] Figure 2 Schematic diagram of the optical path of a device for non-destructive measurement of a target surface in another embodiment;

[0034] Figure 3 is a transmittance curve diagram of a linear dichroic mirror in one embodiment;

[0035] Figure 4 1 is a reflection and transmission image of a linear dichroic mirror in one embodiment;

[0036] Figure 5 is a schematic diagram of the principle of uniform shaping of the first light source in one embodiment;

[0037] Figure 6 A schematic diagram of an optical path of a device for non-destructive measurement of a target surface in another embodiment;

[0038] Figure 7 A schematic diagram of an optical path of a device for non-destructive measurement of a target surface in yet another embodiment;

[0039] Figure 8 1 is a flow chart of a method for non-destructive measurement of a target surface in one embodiment;

[0040] Figure 9 1 is a flow chart of a method for non-destructive measurement of a target surface in yet another embodiment;

[0041] Figure 10 FIG. 4 is a flow chart of a method for non-destructive measurement of a target surface in another embodiment. DETAILED DESCRIPTION

[0042] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of specific embodiments of the present invention is provided in conjunction with the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0045] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0046] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0047] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0048] The current manufacturing process for Micro LED products primarily involves Micro LED epitaxy and the fabrication of Micro LED arrays on sapphire substrates. The performance of Micro LED devices is also highly dependent on epitaxy technology, with stringent requirements placed on epitaxy wavelength consistency, uniformity, and dislocation density. To provide a non-destructive measurement solution for Micro LEDs, this application proposes a device for non-destructive surface measurement of a target object.

[0049] See also Figure 1 , Figure 1 FIG. 1 is a schematic diagram showing an optical path of a non-destructive surface measurement device for a target object in an embodiment of the present invention. The non-destructive surface measurement device for a target object provided by an embodiment of the present invention includes:

[0050] A first light source 1 is used to emit a first excitation light to a target object 2; the target object 2 includes a photoluminescent material; a lens 3 receives and adjusts the target detection light excited by the first excitation light from the target 2; a linear dichroic mirror 4 transmits at least a portion of the target detection light and reflects at least a portion of the target detection light; the transmittance of the linear dichroic mirror 4 increases with an increase in wavelength, and the reflectance decreases with a decrease in wavelength; a first image sensor 5 is arranged on the transmission light path of the linear dichroic mirror 4, and obtains a first grayscale image of the target detection light transmitted by the linear dichroic mirror 4; and a second image sensor 6 is arranged on the reflection light path of the linear dichroic mirror 4, and obtains a second grayscale image of the target detection light reflected by the linear dichroic mirror 4; wherein, by performing image processing on the first grayscale image and the second grayscale image, a centroid spectrum of each point of the target object is obtained; and based on the centroid spectrum of each point of the target object, surface information of the target object is obtained. The first image sensor 5 or the second image sensor 6 may be a CCD (Charge-Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor) or an SCMOS (scientific CMOS).

[0051] Please also see Figure 2 , Figure 2 A schematic diagram of an optical path of a target surface non-destructive measurement device in another embodiment of the present invention is shown. A target surface non-destructive measurement device provided in another embodiment of the present invention includes:

[0052] A first light source 14' is configured to emit a first excitation light to a target 2'; the target 2' comprises a photoluminescent material; a lens 3' receives and adjusts target detection light emitted by the target 2' and excited by the first excitation light; a linear dichroic mirror 4' transmits at least a portion of the target detection light and reflects at least a portion of the target detection light; the transmittance of the linear dichroic mirror 4' increases with increasing wavelength, and the reflectance decreases with decreasing wavelength; a first image sensor 5' is disposed on a transmission light path of the linear dichroic mirror 4' to obtain a first grayscale image of the target detection light transmitted by the linear dichroic mirror 4'; and a second image sensor 6' is disposed on a reflection light path of the linear dichroic mirror 4' to obtain a second grayscale image of the target detection light reflected by the linear dichroic mirror 4'; wherein, by performing image processing on the first grayscale image and the second grayscale image, a centroid spectrum of each point of the target is obtained; and based on the centroid spectrum of each point of the target, surface information of the target is obtained. The first image sensor 5 ′ or the second image sensor 6 ′ may be a CCD (Charge-Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor) or an SCMOS (scientific CMOS).

[0053] Photoluminescence (PL) refers to the process by which a substance re-radiates photons (or electromagnetic waves) after absorbing them. From a quantum mechanical perspective, this process can be described as a transition from a material's absorption of a photon to an excited state with a higher energy level, followed by a return to a lower energy state and the simultaneous emission of a photon. It generally proceeds through three main stages: absorption, energy transfer, and light emission. Both light absorption and emission occur through transitions between energy levels, passing through excited states. Energy transfer is the result of the movement of excited states. For semiconductor materials such as GaN, when exposed to light with photon energy equal to or greater than the band gap, valence band electrons are excited to the conduction band, creating holes in the valence band. These unbalanced electrons and holes can radiatively recombine across the band gap or through localized states within the band gap, releasing their energy as photons and generating photoluminescence. This enables the lighting of GaN-based Micro LEDs, for example, without power, for non-destructive testing.

[0054] It is understandable that for semiconductor materials with different doping ratios, the first light source 1 needs to be replaced with a laser of a different wavelength, which mainly depends on the band gap of the semiconductor material.

[0055] Exemplarily, light of a specific wavelength is emitted from the first light source 1, passes through the second beam splitter prism 16 to turn the light path and enter the main light path, and then is focused by the lens onto the target object, such as the Micro LED sample, i.e., the target surface, so that the Micro LED lamp beads are excited and lit, wherein the lens can be an objective lens. The light emitted by the illuminated target object, i.e., the target detection light, is collected by the objective lens, and passes through the second beam splitter prism 16 again to reach the linear dichroic mirror 4. The linear dichroic mirror 4 is sensitive to the wavelength of light. Within the bandpass allowable range, its transmittance increases with increasing wavelength, and its reflectivity decreases with decreasing wavelength. After the light of a fixed wavelength enters the linear dichroic mirror 4, the light passing through the linear dichroic mirror 4 is collected by the first image sensor 5, and the light reflected by the linear dichroic mirror 4 is collected by the second image sensor 6. By processing the grayscale images, such as the first grayscale image and the second grayscale image, captured by the first image sensor 5 and the second image sensor 6, the centroid spectrum of the light emitted by the sample itself can be reversely deduced, and at the same time, by processing the images, the appearance defects of the sample lamp beads can be detected.

[0056] like Figure 3 Figure 2 shows a transmittance curve for the linear dichroic mirror 4. The horizontal axis represents wavelength (in nanometers), while the vertical axis represents the transmittance of the linear dichroic mirror 4. The linear dichroic mirror 4 is sensitive to the wavelength of light. Within the passband range (400-700 nm), its transmittance increases with increasing wavelength, while its reflectivity decreases with decreasing wavelength. Figure 3 The dashed line is the transmittance curve of the linear dichroic mirror 4, and the solid line is the transmittance curve obtained by fitting the transmittance curve. 2 The value reaches above 0.99. 2 The R-squared value is an indicator used to measure the goodness of fit of a model, especially in a linear regression model, which indicates the degree of linear relationship between the independent variable and the dependent variable. 2 The value ranges from 0 to 1. The closer the value is to 1, the better the model fit and the better the linearity.

[0057] Therefore, under the condition that the linear curve of the linear dichroic prism is known, the transmission wavelength can be inverted by fitting its linear relationship. For example, the linear relationship of the linear dichroic prism is T = kλ+b, then λ = (Tb) / k, as shown in Figure 4 It is the reflection and transmission images collected in the same field of view through the linear dichroic mirror, and the gray value of the pixel at a certain position on the reflection image is G R , take the pixel gray value G at the same position on the transmission image T , we can calculate the sum of the grayscale of the same position on the two images as G, so we can calculate T = G T / G, then λ = ((GT / G)-b) / k.

[0058] Figure 4 In the image, the bright area is the area illuminated by the light spot. The left image is the image reflected by the linear dichroic mirror, and the right image is the image transmitted by the linear dichroic mirror. The bright spot is the LED. The obvious frame in the right image is a typical LED lamp bead in the field of view. The specific identification of bad pixels can be determined by inverting the overall wavelength distribution of a single lamp bead. Uniformity is an important indicator for judging the quality of lamp beads, and the uniformity of wavelength is calculated based on the grayscale of the target being photographed. For example, Figure 4 In the image, a lamp bead is a nearly rectangular white area. Some dark spots will appear in the white area. These are the bad pixel areas of the lamp bead, which can be clearly observed. Of course, there are some areas that cannot be observed by the naked eye and have little difference with the surrounding pixel values. More accurate pixel area calculation is required to know them.

[0059] More importantly, the emission wavelength of Micro LED lamp beads is itself an important indicator to describe whether the LED is qualified and whether it can emit light of a specific wavelength without discoloration or color cast.

[0060] In this embodiment, excitation light is emitted toward a target object having a photoluminescent material. A linear dichroic mirror is positioned in the optical path of target detection light, utilizing the characteristics of the linear dichroic mirror: its transmittance increases with increasing wavelength and its reflectance decreases with decreasing wavelength. A first image sensor is positioned in the transmission optical path of the linear dichroic mirror to obtain a first grayscale image of the target detection light transmitted by the linear dichroic mirror. A second image sensor is positioned in the reflection optical path of the linear dichroic mirror to obtain a second grayscale image of the target detection light reflected by the linear dichroic mirror. Image processing is performed on the first and second grayscale images to obtain a centroid spectrum at each point on the target. Surface information of the target is then obtained based on the centroid spectrum at each point on the target. This allows non-destructive testing of the target to provide surface information about the target. Furthermore, surface defect information about the target can be obtained based on this non-destructive testing. The photoluminescence method of this embodiment effectively captures the state of a lit lamp bead. Based on the captured image, surface defects such as foreign matter and scratches can be detected, similar to automated optical inspection (AOI). Secondly, a defective pixel area may be activated and illuminated, but the brightness may differ from normal areas, or the defective pixel area may not illuminate at all. Therefore, based on the inverted wavelength distribution of the lamp bead, a defective pixel at a specific point on the bead can be detected.

[0061] In this embodiment, a contactless detection device consisting of a first light source, a lens, a linear dichroic mirror, a first image sensor, and a second image sensor can prevent the probe from causing physical damage to the electrodes and surface of the Micro LED chip, thereby enabling wafer-level Micro LED detection to intercept bad pixels and improve the yield rate of the Micro LED display.

[0062] In one embodiment, the target surface non-destructive measurement device further includes: a homogenizer 7, which is located at the emission end of the first light source 1, and is used to receive the first excitation light emitted by the first light source 1 and perform homogenization on the light intensity of the first excitation light.

[0063] For example, light of a specific wavelength is emitted from the first light source 1, homogenized by the light homogenizer 7, and then enters the main light path after being deflected by the second beam splitter prism 16. It is then focused on the target object, such as the surface of the Micro LED sample, so that the Micro LED lamp beads are excited and lit, wherein the lens can be an objective lens. The light emitted by the illuminated target object, i.e., the target detection light, is collected by the objective lens and passes through the second beam splitter prism 16 again to reach the linear dichroic mirror 4. The linear dichroic mirror 4 is sensitive to the wavelength of light. Within the bandpass allowable range, its transmittance increases with increasing wavelength and its reflectivity decreases with decreasing wavelength. After the light of a fixed wavelength enters the linear dichroic mirror 4, the light passing through the linear dichroic mirror 4 is collected by the first image sensor 5, and the light reflected by the linear dichroic mirror 4 is collected by the second image sensor 6. By processing the grayscale images captured by the first image sensor 5 and the second image sensor 6, such as the first grayscale image and the second grayscale image, the centroid spectrum of the light emitted by the sample itself can be reversely deduced. At the same time, by processing the images, the appearance defects of the sample lamp beads can be detected.

[0064] In order to make GaN semiconductor materials photoluminescent, the photon energy must be greater than its band gap to excite the valence band electrons. Therefore, in this example, a semiconductor laser that meets this requirement is used as the excitation light source. The semiconductor laser has a narrow bandwidth, and its central wavelength drift and energy are stable. During the test, the Micro LED lamp beads can be stably lit. However, the light field distribution of the laser output beam is a Gaussian beam, that is, the light intensity of the beam gradually decreases from the center to the edge of the beam, such as Figure 5The distribution pattern of the graph on the left shows that the energy distribution is dense in the center and the light intensity is the highest. The farther away from the center, the sparser the energy distribution and the weaker the light intensity. From the principle of photoluminescence, it can be seen that the photoluminescence intensity of Micro LED lamp beads excited by light of different intensities is different. The linear dichroic mirror inversion wavelength used in this example is based on the lamp beads in the field of view of the image sensor being excited by a beam of the same light intensity. When the excitation beam is a Gaussian beam, it is necessary to perform beam analysis calibration on the Gaussian beam, which greatly increases the calculation process and cost and introduces more errors. Therefore, the Gaussian beam is first shaped by the homogenizer 7 so that the beam emitted to the surface of the MicroLED lamp bead is uniformly distributed.

[0065] In one embodiment, the light homogenizer 7 is a homogenizing optical fiber, and the input end of the homogenizing optical fiber has multiple interfaces, which can receive the first excitation light of different wavelengths.

[0066] Among various beam shaping methods, the liquid core fiber homogenization method has lower cost, wider transmission spectrum range, and better homogenization rate than traditional quartz fiber. Therefore, it is optional to use liquid core homogenization fiber to transform the energy distribution of the laser output light from Gaussian distribution to uniform distribution spot, such as Figure 5 The figure shows how the intensity distribution of a Gaussian beam becomes uniform after homogenization. A circular or square spot can be selected based on the actual situation. A uniformly distributed spot ensures uniform excitation of the sample across the field of view, eliminating the need for repeated incident light power calibration calculations at different spot positions during measurement.

[0067] For semiconductor materials with different doping ratios, the first light source needs to be replaced with a laser of a different wavelength, which mainly depends on the bandgap of the semiconductor material. Therefore, the input end of a light homogenizer, such as a homogenizing fiber, has multiple interfaces to transmit light of different wavelengths.

[0068] In this embodiment, in order to ensure that the intensity of the excitation light emitted by the light source can be evenly distributed when irradiating the target object, a homogenizer is used to perform light homogenization processing, so that the light intensity reaches a relatively uniform state on the surface of the target object, thereby avoiding differences in excitation effects caused by uneven light intensity and improving the accuracy and reliability of the measurement.

[0069] In one embodiment, the target surface non-destructive measurement device further includes: a collimator 8, which is located at the output end of the homogenizer 7, and is used to receive the homogenized first excitation light and adjust the emission angle of the first excitation light to be perpendicular to the surface of the target object.

[0070] For example, light of a specific wavelength is emitted from the first light source 1, homogenized by the light homogenizer 7, collimated by the collimator 8, and then enters the main light path after being deflected by the second beam splitter prism 16. It is then focused onto the target object, such as the surface of the Micro LED sample, through the lens, so that the Micro LED lamp beads are excited and lit, wherein the lens can be an objective lens. The light emitted by the illuminated target object, that is, the target detection light, is collected by the objective lens, and then passes through the second beam splitter prism 16 again to reach the linear dichroic mirror 4. The linear dichroic mirror 4 is sensitive to the wavelength of light. Within the bandpass allowable range, its transmittance increases with increasing wavelength, and its reflectivity decreases with decreasing wavelength. After the light of a fixed wavelength enters the linear dichroic mirror 4, the light passing through the linear dichroic mirror 4 is collected by the first image sensor 5, and the light reflected by the linear dichroic mirror 4 is collected by the second image sensor 5. By processing the grayscale images captured by the first image sensor 5 and the second image sensor 6, such as the first grayscale image and the second grayscale image, the centroid spectrum of the light emitted by the sample itself can be reversely deduced. At the same time, by processing the images, the appearance defects of the sample lamp beads can be detected.

[0071] In this embodiment, the purpose of collimating the excitation light is to ensure that the excitation light beam is incident perpendicularly to the surface of the target object. If the beam is at an angle to the material surface, the incident angle of the photons will no longer be uniform, which will cause the photon propagation path within the material and the excitation effect to change. By collimating the beam, the beam can be incident at a perpendicular angle to the material surface, thus ensuring consistent and repeatable excitation effects.

[0072] In one embodiment, the target surface non-destructive measurement device further includes: a second beam splitter prism 16 disposed between the lens 3 and the linear dichroic mirror 4 and capable of deflecting the first excitation light.

[0073] In one embodiment, the target surface non-destructive measurement device further includes: a first filter 9 located in the optical path between the lens 3 and the linear dichroic mirror 4, for filtering out the excitation light reflected by the target and transmitting the detection light through the target.

[0074] For example, please refer to Figure 1Light of a specific wavelength is emitted from the first light source 1, passes through the homogenizer 7 and the collimator 8, and then enters the main light path after being turned by the second beam splitter prism 16. It is then focused on the target object, such as the surface of the Micro LED sample, so that the Micro LED lamp beads are excited and lit, wherein the lens can be an objective lens. The light emitted by the illuminated target object, i.e., the target detection light, and the light reflected by the first light source 1 on the target object 2 are collected by the objective lens at the same time, and then pass through the second beam splitter prism 16 again to reach the first filter 9. The first filter 9 selects the wavelength of the light, allowing the light emitted by the sample itself, i.e., the target detection light, to pass through, and prevents the light of the wavelength band reflected back by the first light source 1 from passing through. The target detection light emitted by the target itself passes through the first filter 9 and reaches the linear dichroic mirror 4. The linear dichroic mirror 4 is sensitive to the wavelength of light. Within the bandpass allowable range, its transmittance increases with the increase of wavelength, and its reflectivity decreases with the decrease of wavelength. After light of a fixed wavelength enters the linear dichroic mirror 4, the light transmitted through the linear dichroic mirror 4 is captured by the first image sensor 5, and the light reflected by the linear dichroic mirror 4 is captured by the second image sensor 6. By processing the grayscale images captured by the first image sensor 5 and the second image sensor 6, such as the first grayscale image and the second grayscale image, the centroid spectrum of the light emitted by the sample itself can be reversely deduced. At the same time, through image processing, the appearance defects of the sample lamp beads can be detected.

[0075] In one embodiment, please refer to Figure 6 , Figure 6Schematic diagram of the optical path of a non-destructive surface measurement device for an object in another embodiment. Another embodiment of the present invention provides a non-destructive surface measurement device for an object, further comprising: an aperture 10, located at the emission end of the first light source 1, capable of blocking part of the light spot of the first excitation light to obtain a second excitation light; a lens 11, opposite the aperture 10, receiving the second excitation light, and collimating the second excitation light, thereby converting the divergent light into parallel light; and the lens 11 also receiving and converging a third excitation light; wherein the third excitation light is obtained by reflecting the second excitation light from the object; a second filter 12, located on the optical path between the lens 3 and the lens 11, for filtering out the target detection light and transmitting the third excitation light; a third image sensor 13, receiving the third excitation light and obtaining a light spot image of the third excitation light; obtaining the defocus of the lens based on the light spot image of the third excitation light, and adjusting the distance between the lens and the object based on the defocus. The third image sensor 13 may be a CCD (Charge-Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), a SCMOS (scientific CMOS), or an AF CCD (Auto Focus Charge-Coupled Device).

[0076] In one embodiment, the target surface non-destructive measurement device further includes: a first beam splitter prism 15 disposed between the aperture 10 and the lens 11 , capable of deflecting the light converged by the lens 11 to the third image sensor 13 .

[0077] For example, light of a specific wavelength is emitted from the first light source 1, which emits a circular light spot. After passing through the homogenizer 7 and the collimator 8, the aperture 10 in the output path will prevent half of the light spot of the first light source 1 from entering the light path. Therefore, the light from the first light source 1 passes through the first dichroic prism 15 in the form of a semicircle, is converged into parallel light by the lens 11, passes through the second filter 12, and then passes through the second dichroic prism 16 to turn the light path and enter the main light path. It is then focused on the surface of the Micro LED sample, i.e., the target object 2, through the lens 3, so that the Micro LED lamp beads are excited and lit, wherein the lens 3 can be an objective lens. The light emitted by the illuminated target, i.e., the target detection light, and the light reflected by the first light source 1 on the sample are collected by the objective lens at the same time, and after passing through the second dichroic prism 16, reach the first filter 9. The first filter 9 selects the wavelength of the light, allowing the light emitted by the sample itself, i.e., the target detection light, to pass through, and preventing the light of the wavelength band reflected back by the first light source 1 from passing through. Light emitted by the target 2, or the target detection light, passes through the first filter 9 and reaches the linear dichroic mirror 4. The linear dichroic mirror 4 is sensitive to light wavelength. Within its passband, its transmittance increases with increasing wavelength, while its reflectance decreases with decreasing wavelength. After light of a fixed wavelength enters the linear dichroic mirror 4, the light transmitted through the mirror 4 is captured by the first image sensor 5, while the light reflected from the mirror 4 is captured by the second image sensor 6. By processing the grayscale images captured by the first and second image sensors 5 and 6, such as the first and second grayscale images, the centroid spectrum of the light emitted by the sample itself can be reversely deduced. This image processing also allows for the detection of surface defects in the sample's lamp beads. Furthermore, the reflected light from the first light source 1 is passed through the second filter 12, while potential interfering light, such as the target detection light emitted by the sample itself, is blocked by the second filter 12. The light then passes through the lens 11 and the first beam splitter prism 15 before being reflected to the third image sensor 13. The third image sensor 13 collects the direction and radius of the semicircular light spot reflected by the first light source 1 to determine whether the sample is out of focus, thereby performing fast autofocus. The third image sensor 13 can be an AF CCD (Auto Focus Charge-Coupled Device).

[0078] For typical lens imaging, the focal length, object distance, and image distance of the lens satisfy the Gaussian formula (1):

[0079] 1 / f = 1 / u + 1 / v (1)

[0080] Where f represents the focal length of the optical system, u is the object distance of the corresponding optical system, and v is the image distance of the corresponding optical system.

[0081] according to Figure 6The optical path formed by the lens 3 and the lens 11 in the device can establish the defocus amount z and the radius R of the semicircle detected by the third image sensor 13. x The mathematical relationship between them is shown in formula (2):

[0082] R x = (2f2 / f1)×z×tanθ (2)

[0083] Where f1 is the focal length of lens 3, f2 is the focal length of lens 11, z is the defocus amount, and tanθ is the lens constant NA (numerical aperture).

[0084] Specifically, if a defocus amount z occurs when detecting a sample, the third image sensor 13 can detect a semicircular light spot, where the defocus amount z and the radius R of the light spot are x In a linear relationship, when the system is defocused, z>0, then R x >0, producing an upper semicircle; when the focus is down and z<0, then R x <0, generating a lower semicircle. The third image sensor 13, in conjunction with a measurement algorithm, can then quickly calculate the radius and direction of the semicircle, thereby calculating the defocus value z. The signal output controls the motor's rapid movement to the target position, thereby achieving system focus. Optionally, the system can be fixed while the wafer moves, achieving real-time focusing and real-time acquisition.

[0085] In this example, the first grayscale image and the second grayscale image obtained by the first image sensor 5 and the second image sensor 6 are collected by using a linear dichroic mirror to invert the wavelength. The actual wavelength of the corresponding target detection light is deduced by calculating the grayscale of the same pixel position in the two images. Therefore, the consistency of the image size, position deviation accuracy and imaging clarity of the first image sensor 5 and the second image sensor 6 obtained is very high. Placing the first image sensor 5 and the second image sensor 6 in the same optical path can effectively avoid the errors caused by image size and position deviation. Furthermore, in this example, an objective lens such as a microscope objective lens is used, which has a small depth of field. Small height differences at different positions of the same target object will cause differences in imaging clarity. Therefore, an autofocus component is added to eliminate the errors of inconsistent imaging clarity caused by height differences at different positions of the same product, thereby improving detection accuracy.

[0086] In one embodiment, please refer to Figure 7 , Figure 7A schematic diagram of the optical path of a non-destructive surface measurement device for an object in another embodiment. The present invention further provides a non-destructive surface measurement device for an object, further comprising: a second light source 1' for emitting a fourth excitation light beam toward the object; the fourth excitation light beam having a wavelength greater than that of the first excitation light beam; an aperture 10' located at the emission end of the second light source 1' and capable of blocking a portion of the fourth excitation light beam spot to generate a fifth excitation light beam; a lens 11', opposite the aperture 10', receiving the fifth excitation light beam and collimating the fifth excitation light beam to convert divergent light beams into parallel light beams; and a lens 11' further receiving and converging a sixth excitation light beam, wherein the sixth excitation light beam is generated by reflection of the fifth excitation light beam from the object; a second filter 12' located in the optical path between the lens 3' and the lens 11' and configured to filter out the target detection light beam and transmit the fifth and sixth excitation light beams; a third image sensor 13' receiving the sixth excitation light beam and generating a spot image of the sixth excitation light beam; determining the lens defocus value based on the spot image of the sixth excitation light beam, and adjusting the distance between the lens and the object based on the defocus value. The third image sensor 13 ′ may be a CCD (Charge-Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), a SCMOS (scientific CMOS), or an AF CCD (Auto Focus Charge-Coupled Device).

[0087] In one embodiment, the target surface non-destructive measurement device further includes: a third beam splitter prism 17', which is arranged on the optical path between the second filter 12' and the lens 3', and can deflect the fifth excitation light to the lens 3' and deflect the sixth excitation light to the second filter 12'.

[0088] Exemplarily, light of a specific wavelength is emitted from the first light source 14', passes through the homogenizer 7' and the collimator 8', and then enters the main light path after being turned by the second dichroic prism 16'. After passing through the third dichroic prism 17', it is focused onto the Micro LED sample, i.e., the surface of the target object, through the lens 3', so that the Micro LED lamp beads are excited and lit, wherein the lens 3' can be an objective lens. The light emitted by the illuminated target object, i.e., the target detection light, and the light reflected from the first light source 14' onto the sample are collected by the objective lens at the same time, and after passing through the third dichroic prism 17' and the second dichroic prism 16', they reach the first filter 9'. The first filter 9' selects the wavelength of light, allowing the light emitted by the sample itself, i.e., the target detection light, to pass through, and preventing the light of the wavelength band reflected back by the first light source 14' from passing through. Light emitted by the target 2' passes through the first filter 9' and reaches the linear dichroic mirror 4'. This mirror is sensitive to light wavelength. Within its passband, its transmittance increases with increasing wavelength, while its reflectance decreases with decreasing wavelength. After light of a fixed wavelength enters the linear dichroic mirror 4', the light transmitted through the mirror 4' is captured by the first image sensor 5', while the light reflected by the mirror 4' is captured by the second image sensor 6'. By processing the grayscale images captured by the first and second image sensors 5', such as the first and second grayscale images, the centroid spectrum of the light emitted by the sample can be reversely deduced. Simultaneously, through image processing, the sample's lamp beads can be inspected for defects. The second light source 1' is a laser light source with a wavelength greater than that of the first light source 14', and its wavelength is blocked by the first filter 9'. The second light source 1' emits a circular light spot, and an aperture 10' in the output path prevents half of the second light source 1' light spot from entering the optical path. Therefore, the light from the second light source 1' passes through the first dichroic prism 15' in the form of a semicircle, is collimated into parallel light by the lens 11', and then passes through the second filter 12' to enter the third dichroic prism 17'. After being reflected by the third dichroic prism 17', it passes through the lens 3 and enters the sample surface. Similarly, the light from the second light source 1' reflected back will pass through the second filter 12', while possible interfering light such as the reflected light from the first light source 14' and the target detection light emitted by the sample itself will be blocked by the second filter 12'. The light from the second light source 1' reflected back is the sixth excitation light. The direction and radius of the semicircular light spot reflected back from the second light source 1' are collected by the third image sensor 13' to determine whether the sample is out of focus, so as to perform fast automatic focusing. The third image sensor 13' can be an AF CCD (AutoFocus Charge-Coupled Device).

[0089] For typical lens imaging, the focal length, object distance, and image distance of the lens satisfy the Gaussian formula (3):

[0090] 1 / f = 1 / u + 1 / v (3)

[0091] Where f represents the focal length of the optical system, u is the object distance of the corresponding optical system, and v is the image distance of the corresponding optical system.

[0092] according to Figure 7 The optical path formed by the lens 3' and the lens 11' in the device can establish the defocus amount z and the radius R of the semicircle detected by the third image sensor 13'. x The mathematical relationship between them is shown in formula (4):

[0093] R x = (2f2 / f1)×z×tanθ (4)

[0094] Where f1 is the focal length of the lens 3 ′, f2 is the focal length of the lens 11 ′, z is the defocus, and tanθ is the fixed value NA (numerical aperture) of the lens.

[0095] Specifically, if a defocus amount z occurs when detecting a sample, the third image sensor 13' can detect a semicircular light spot, wherein the defocus amount z and the radius R of the light spot are x In a linear relationship, when the system is defocused, z>0, then R x >0, producing an upper semicircle; when the focus is down and z<0, then R x <0, generating a lower semicircle. The third image sensor 13', in conjunction with a measurement algorithm, can quickly calculate the radius and direction of the semicircle, thereby calculating the defocus value z. Signal output controls the motor's rapid movement to the target position, achieving system focus. Optionally, the system can be fixed while the wafer moves, enabling real-time focusing and acquisition.

[0096] In this example, the first and second grayscale images acquired by the first and second image sensors 5' and 6' are acquired by using a linear dichroic mirror to invert the wavelength. The actual wavelength of the corresponding target detection light is deduced by calculating the grayscale at the same pixel position in the two images. Therefore, the consistency of the image size, position deviation accuracy, and image clarity of the acquired first and second image sensors 5' and 6' is very high. Placing the first and second image sensors 5' and 6' in the same optical path can effectively avoid errors caused by image size and position deviation. Furthermore, in this example, the objective lens used, such as a microscope objective lens, has a small depth of field. Small height differences at different positions on the same target object can cause differences in image clarity. Therefore, the addition of an autofocus component can eliminate the error of inconsistent image clarity caused by height differences at different positions on the same product, thereby improving detection accuracy. In addition, the integration of the autofocus system into the PL detection device can simultaneously complete spectral detection and AOI detection items, thereby improving detection speed and reducing costs.

[0097] For example, please refer to Figure 7 In one embodiment, the first filter 9 is also used to filter out the sixth excitation light.

[0098] It can be understood that placing the target surface non-destructive measurement device in an automated inspection device, combined with a robot and control system, can achieve a fast and automatic inspection process, and complete the sorting of OK (good) products and NG (Not Good) products, thereby improving the production yield of Micro LEDs.

[0099] Based on the same concept, the present application also provides a method for non-destructive measurement of the surface of a target object, such as Figure 8 As shown, the process includes the following steps 802 to 810.

[0100] Step 802: Control the first light source to emit first excitation light; the first excitation light is adjusted by a lens and incident on the target, exciting the target to emit target detection light; the target detection light is again adjusted by the lens and incident on a linear dichroic mirror, at least part of the target detection light passes through the linear dichroic mirror, and at least part of the target detection light is reflected by the linear dichroic mirror; the transmittance of the linear dichroic mirror increases with increasing wavelength, and the reflectance decreases with decreasing wavelength.

[0101] Step 804 : Receive at least a portion of the target detection light transmitted through the linear dichroic mirror via a first image sensor to generate a first grayscale image.

[0102] Step 806 : Receive at least a portion of the target detection light reflected by the linear dichroic mirror via a second image sensor to generate a second grayscale image.

[0103] Step 808 : performing image processing on the first grayscale image and the second grayscale image to obtain a centroid spectrum of each point of the target object.

[0104] Step 810 : Obtaining surface information of the target object based on the centroid spectrum of each point of the target object.

[0105] For example, please refer to Figure 1. The non-destructive measurement method of the target surface proposed in this embodiment includes: controlling the first light source 1 to emit a first excitation light. The first excitation light is adjusted by the lens 3 and incident on the target 2, exciting the target 2 to emit a target detection light. The target detection light is adjusted again by the lens 3 and incident on the linear dichroic mirror 4, at least part of the target detection light passes through the linear dichroic mirror 4, and at least part of the target detection light is reflected by the linear dichroic mirror 4; the transmittance of the linear dichroic mirror 4 increases with the increase of wavelength, and the reflectivity decreases with the decrease of wavelength. At least part of the target detection light that passes through the linear dichroic mirror 4 is received by the first image sensor to generate a first grayscale image; at least part of the target detection light that is reflected by the linear dichroic mirror 4 is received by the second image sensor to generate a second grayscale image. Image processing is performed on the first grayscale image and the second grayscale image to obtain the centroid spectrum of each point of the target; based on the centroid spectrum of each point of the target 2, the surface information of the target 2 is obtained.

[0106] For example, please refer again Figure 2 , Figure 2 A method for nondestructive surface measurement of an object in another embodiment of the present invention is shown, comprising: controlling a first light source 14' to emit a first excitation light. The first excitation light is modulated by a lens 3' and incident on an object 2', thereby stimulating the object 2' to emit a target detection light. The target detection light is again modulated by the lens 3' and incident on a linear dichroic mirror 4'. At least a portion of the target detection light passes through the linear dichroic mirror 4', while at least a portion of the target detection light is reflected by the linear dichroic mirror 4'. The transmittance of the linear dichroic mirror 4' increases with increasing wavelength, while the reflectance decreases with decreasing wavelength. A first image sensor receives at least a portion of the target detection light that passes through the linear dichroic mirror 4' to generate a first grayscale image. A second image sensor receives at least a portion of the target detection light that is reflected by the linear dichroic mirror to generate a second grayscale image. Image processing is performed on the first and second grayscale images to obtain a centroid spectrum of each point on the object. Surface information of the object is obtained based on the centroid spectrum of each point on the object.

[0107] In this embodiment, the target object detection light is separated by a linear dichroic mirror and then incident on a first image sensor and a second image sensor respectively, thereby obtaining a first grayscale image and a second grayscale image, respectively. The first grayscale image and the second grayscale image are processed to obtain a centroid spectrum of each point of the target object. Based on the centroid spectrum of each point of the target object, the surface information of the target object is obtained. This can prevent the probe from causing physical damage to the electrodes and surface of the Micro LED chip, thereby enabling wafer-level Micro LED detection to intercept bad pixels and improve the yield rate of Micro LED displays.

[0108] In one embodiment, the centroid spectrum of each point of the target object is obtained by performing image processing on the first grayscale image and the second grayscale image, including: obtaining a transmittance curve of a linear dichroic mirror; fitting the transmittance curve to obtain a relationship between the wavelength and transmittance of light passing through the linear dichroic mirror; obtaining the grayscale value G of the first pixel at the first position in the first grayscale image. T , obtain the grayscale value G of the second pixel at the second position in the second grayscale image R ; Wherein the first position and the second position correspond to the same point of the target object; based on the first pixel grayscale value and the second pixel grayscale value, the total grayscale value of the same point of the target object is obtained; based on the total grayscale value and the relationship between the wavelength of the light wave and the transmittance, the centroid spectrum of the same point of the target object is obtained, and then the centroid spectrum of each point of the target object is obtained.

[0109] Specifically, such as Figure 3 Figure 2 shows a transmittance curve for the linear dichroic mirror 4. The horizontal axis represents wavelength (in nanometers), while the vertical axis represents the transmittance of the linear dichroic mirror 4. The linear dichroic mirror 4 is sensitive to the wavelength of light. Within the passband range (400-700 nm), its transmittance increases with increasing wavelength, while its reflectivity decreases with decreasing wavelength. Figure 3 The dashed line is the transmittance curve of the linear dichroic mirror 4, and the solid line is the transmittance curve obtained by fitting the transmittance curve. 2 The value reaches above 0.99. 2 The R-squared value is an indicator used to measure the goodness of fit of a model, especially in a linear regression model, which indicates the degree of linear relationship between the independent variable and the dependent variable. 2 The value ranges from 0 to 1. The closer the value is to 1, the better the model fit and the better the linearity.

[0110] Therefore, if the linear curve of the linear dichroic prism is known, the wavelength of the light wave passing through the linear dichroic mirror can be inverted by fitting its linear relationship. For example, the linear relationship of the linear dichroic prism is T = kλ + b, then λ = (Tb) / k, where λ is the wavelength of the light wave passing through the linear dichroic mirror, k and b are constants, and T represents the transmittance of the linear dichroic mirror. Figure 4 It is the reflection and transmission images collected in the same field of view through the linear dichroic mirror, and the grayscale value G of the reflected pixel at a certain position on the reflected image is taken. R , take the transmission pixel gray value G at the same position on the transmission image T , we can calculate the total grayscale of the same position on the two images, that is, the sum of the grayscale is G, so we can calculate T = G T / G, then λ = ((G T / G)-b) / k, that is, the wavelength λ of the light wave passing through the linear dichroic mirror and the sum of the grayscale G at the same position on the two images and the pixel grayscale value G at the same position on the transmission image T Furthermore, the wavelength λ of the light wave passing through the linear dichroic mirror is related to the grayscale value G of the transmitted pixel. T It is proportional to the ratio of the total grayscale G.

[0111] In one embodiment, before generating a first grayscale image by receiving at least a portion of the target detection light transmitted through the linear dichroic mirror through a first image sensor, the method for non-destructive measurement of the target surface further includes: obtaining a second excitation light after a portion of the first excitation light spot is blocked by an aperture; the second excitation light is received and collimated by a lens, thereby converting the divergent light into parallel light; the collimated second excitation light passes through a second filter and a lens and is incident on the target, and is reflected by the target to obtain a third excitation light; the third excitation light passes through a second filter to remove the target detection light and is incident on the lens; the third excitation light converged by the lens is received by a third image sensor to generate a spot image of the third excitation light; the defocus amount of the lens is obtained according to the spot image of the third excitation light, and the distance between the lens and the target is adjusted based on the defocus amount.

[0112] For example, please refer to Figure 6 . Figure 6A method for nondestructive surface measurement of a target object in another embodiment of the present invention is shown, comprising: controlling a first light source 1 to emit a first excitation light. The first excitation light is modulated by a lens 3 and incident on a target object 2, thereby stimulating the target object 2 to emit a target detection light. The target detection light is again modulated by the lens 3 and incident on a linear dichroic mirror 4. At least a portion of the target detection light is transmitted through the linear dichroic mirror 4, and at least a portion of the target detection light is reflected by the linear dichroic mirror 4. The transmittance of the linear dichroic mirror 4 increases with increasing wavelength, while the reflectance decreases with decreasing wavelength. Part of the first excitation light spot is also blocked by the aperture 10, thereby obtaining a second excitation light; the second excitation light is received and collimated by the lens 11, thereby converting the divergent light into a parallel light; the collimated second excitation light passes through the second filter 12 and the lens 3 and is incident on the target 2, and is reflected by the target 2 to obtain a third excitation light; the third excitation light passes through the second filter 12 to remove the target detection light and is incident on the lens 11; the third excitation light converged by the lens 11 is received by the third image sensor to generate a spot image of the third excitation light; the defocus amount of the lens is obtained based on the spot image of the third excitation light, and the distance between the lens and the target is adjusted based on the defocus amount. The first image sensor receives at least a portion of the target detection light that passes through the linear dichroic mirror 4 to generate a first grayscale image; the second image sensor receives at least a portion of the target detection light reflected by the linear dichroic mirror 4 to generate a second grayscale image. The first grayscale image and the second grayscale image are processed to obtain a centroid spectrum of each point of the target object; and surface information of the target object 2 is obtained based on the centroid spectrum of each point of the target object 2.

[0113] In this example, the first grayscale image and the second grayscale image obtained by the first image sensor 5 and the second image sensor 6 are collected by using a linear dichroic mirror to invert the wavelength. The actual wavelength of the corresponding target detection light is deduced by calculating the grayscale of the same pixel position in the two images. Therefore, the consistency of the image size, position deviation accuracy and imaging clarity of the first image sensor 5 and the second image sensor 6 obtained is very high. Placing the first image sensor 5 and the second image sensor 6 in the same optical path can effectively avoid the errors caused by image size and position deviation. Furthermore, in this example, an objective lens such as a microscope objective lens is used, which has a small depth of field. Small height differences at different positions of the same target object will cause differences in imaging clarity. Therefore, an autofocus component is added to eliminate the errors of inconsistent imaging clarity caused by height differences at different positions of the same product, thereby improving detection accuracy.

[0114] In one embodiment, before generating a first grayscale image by receiving at least a portion of the target detection light transmitted through the linear dichroic mirror through the first image sensor, the method for non-destructive measurement of the target surface further includes: controlling the second light source to emit a fourth excitation light; the wavelength of the fourth excitation light is greater than the wavelength of the first excitation light; a portion of the light spot of the fourth excitation light is blocked by an aperture to obtain a fifth excitation light; the fifth excitation light is received and collimated by a lens, thereby converting the divergent light into a parallel light; the collimated fifth excitation light passes through a second filter and a lens and is incident on the target, and is reflected by the target to obtain a sixth excitation light; the sixth excitation light passes through a second filter to remove the target detection light and is incident on the lens; the sixth excitation light is received by a third image sensor after being converged by the lens to generate a spot image of the sixth excitation light; the defocus amount of the lens is obtained according to the spot image of the sixth excitation light, and the distance between the lens and the target is adjusted based on the defocus amount.

[0115] For example, please refer to Figure 7 . Figure 7 A method for nondestructive surface measurement of a target object in another embodiment of the present invention is shown, comprising: controlling a first light source 14' to emit first excitation light. The first excitation light is modulated by a lens 3' and incident on a target object 2', thereby stimulating the target object 2' to emit target detection light. The target detection light is again modulated by the lens 3' and incident on a linear dichroic mirror 4'. At least a portion of the target detection light is transmitted through the linear dichroic mirror 4', and at least a portion of the target detection light is reflected by the linear dichroic mirror 4'. The transmittance of the linear dichroic mirror 4' increases with increasing wavelength, while the reflectance decreases with decreasing wavelength. The second light source 1' is controlled to emit a fourth excitation light; the wavelength of the fourth excitation light is greater than that of the first excitation light; a portion of the fourth excitation light spot is blocked by the aperture 10', thereby obtaining a fifth excitation light; the fifth excitation light is received and collimated by the lens 11', thereby converting the divergent light into a parallel light; the collimated fifth excitation light passes through the second filter 12' and the lens 3' and is incident on the target 2, where it is reflected by the target 2 to obtain a sixth excitation light; the sixth excitation light passes through the second filter 12' to remove the target detection light and is incident on the lens 11'; the sixth excitation light converged by the lens 11' is received by the third image sensor to generate a spot image of the sixth excitation light; the lens defocus is obtained based on the spot image of the sixth excitation light, and the distance between the lens and the target is adjusted based on the defocus. The first image sensor receives at least a portion of the target detection light that passes through the linear dichroic mirror 4' to generate a first grayscale image; the second image sensor receives at least a portion of the target detection light reflected by the linear dichroic mirror to generate a second grayscale image. The first grayscale image and the second grayscale image are processed to obtain a centroid spectrum of each point of the target object; and surface information of the target object 2 is obtained based on the centroid spectrum of each point of the target object 2.

[0116] In this example, the first grayscale image and the second grayscale image acquired by the first image sensor 5' and the second image sensor 6' are collected by using a linear dichroic mirror to invert the wavelength. The actual wavelength of the corresponding target detection light is deduced by calculating the grayscale of the same pixel position in the two images. Therefore, the consistency of the image size, position deviation accuracy and imaging clarity acquired by the first image sensor 5' and the second image sensor 6' is very high. Placing the second image sensor 5' and the second image sensor 6' in the same optical path can effectively avoid the errors caused by image size and position deviation. Furthermore, in this example, an objective lens such as a microscope objective lens is used, which has a small depth of field. Small height differences at different positions of the same target object will cause differences in imaging clarity. Therefore, an autofocus component is added to eliminate the errors of inconsistent imaging clarity caused by height differences at different positions of the same product, thereby improving detection accuracy.

[0117] In an exemplary embodiment, Figure 9 As shown, the present application also provides a method for non-destructive measurement of a target surface, including steps 902 to 922.

[0118] Step 902, controlling the first excitation light emitted by the first light source; after the first excitation light passes through the light homogenizer and the collimator, part of the light spot is blocked by the aperture to obtain the second excitation light; after the second excitation light passes through the first dichroic prism, it is received and collimated by the lens, thereby converting the divergent light into parallel light; the collimated second excitation light passes through the second filter and then deflected by the second dichroic prism, and then is incident on the target object through the lens, and is reflected by the target object to obtain the third excitation light; and at the same time, the target object is excited to emit target detection light; after passing through the lens, the third excitation light is deflected again by the second dichroic prism, and then filtered out by the second filter to remove the target detection light and is incident on the lens.

[0119] Step 904 : Receive the third excitation light converged by the lens through a third image sensor to generate a spot image of the third excitation light.

[0120] Step 906 : Obtain the defocus amount of the lens according to the spot image of the third excitation light.

[0121] Step 908: Adjust the distance between the lens and the target object based on the defocus amount.

[0122] In step 910, the target detection light is again adjusted by the lens and then incident on the first filter through the second beam splitter prism. After the third excitation light reflected by the target is filtered out by the first filter, the light is incident on the linear dichroic mirror. At least part of the target detection light passes through the linear dichroic mirror, and at least part of the target detection light is reflected by the linear dichroic mirror. The transmittance of the linear dichroic mirror increases with increasing wavelength, and the reflectance decreases with decreasing wavelength.

[0123] Step 912 : Receive at least a portion of the target detection light transmitted through the linear dichroic mirror via a first image sensor to generate a first grayscale image.

[0124] Step 914 : Receive at least a portion of the target detection light reflected by the linear dichroic mirror via a second image sensor to generate a second grayscale image.

[0125] Step 916 , obtaining a transmittance curve of the linear dichroic mirror; fitting the transmittance curve to obtain a relationship between the wavelength of light passing through the linear dichroic mirror and the transmittance.

[0126] Step 918: Obtain the grayscale value G of the first pixel at the first position in the first grayscale image. T , obtain the grayscale value G of the second pixel at the second position in the second grayscale image R ; wherein the first position and the second position correspond to the same point of the target object.

[0127] Step 920, obtaining the total grayscale value of the same point of the target object based on the first pixel grayscale value and the second pixel grayscale value; obtaining the centroid spectrum of the same point of the target object based on the total grayscale value and the relationship between the wavelength of the light wave and the transmittance, and then obtaining the centroid spectrum of each point of the target object.

[0128] Step 922 : Obtain surface information of the target object based on the centroid spectrum of each point of the target object.

[0129] In an exemplary embodiment, Figure 10 As shown, the present application also provides a method for non-destructive measurement of a target surface, including the following steps 1002 to 1020.

[0130] Step 1002: Control the first light source to emit a first excitation light. After passing through a light homogenizer and a collimator, the first excitation light is deflected onto a third dichroic prism via a second dichroic prism. The first excitation light passing through the third dichroic prism is adjusted by a lens and incident on a target, exciting the target to emit target detection light. The first excitation light is also reflected by the target. The target detection light and the first excitation light reflected by the target are again adjusted by a lens and incident on the second dichroic prism via the third dichroic prism. After passing through the second dichroic prism, the target detection light is incident on a first filter, and stray light is filtered out by the first filter. The stray light includes the first excitation light reflected by the target and the sixth excitation light. The target detection light is incident on a linear dichroic mirror. At least part of the target detection light passes through the linear dichroic mirror, and at least part of the target detection light is reflected by the linear dichroic mirror. The transmittance of the linear dichroic mirror increases with increasing wavelength, and the reflectance decreases with decreasing wavelength.

[0131] Step 1004: Control the second light source to emit a fourth excitation light; the wavelength of the fourth excitation light is greater than that of the first excitation light; a portion of the fourth excitation light spot is blocked by an aperture, resulting in a fifth excitation light. After passing through the first beam splitter prism, the fifth excitation light is received and collimated by a lens, thereby converting the divergent light into parallel light. The collimated fifth excitation light passes through the second filter, is deflected by the third beam splitter prism, and then incident on the target object through the lens. After being reflected by the target object, a sixth excitation light is obtained. After passing through the lens, the sixth excitation light is deflected again by the third beam splitter prism, filtered out by the second filter, and then incident on the lens to remove the target detection light.

[0132] Step 1006 : Receive the sixth excitation light converged by the lens through the third image sensor to generate a spot image of the sixth excitation light.

[0133] Step 1008 : Obtain the defocus amount of the lens according to the spot image of the sixth excitation light, and adjust the distance between the lens and the target object based on the defocus amount.

[0134] Step 1010 : Receive at least a portion of the target detection light transmitted through the linear dichroic mirror via a first image sensor to generate a first grayscale image.

[0135] Step 1012 : Receive at least a portion of the target detection light reflected by the linear dichroic mirror via a second image sensor to generate a second grayscale image.

[0136] Step 1014 , obtaining a transmittance curve of the linear dichroic mirror; fitting the transmittance curve to obtain a relationship between the wavelength of light passing through the linear dichroic mirror and the transmittance.

[0137] Step 1016: Obtain the grayscale value G of the first pixel at the first position in the first grayscale image. T , obtain the grayscale value G of the second pixel at the second position in the second grayscale image R ; wherein the first position and the second position correspond to the same point of the target object.

[0138] Step 1018, based on the grayscale value of the first pixel and the grayscale value of the second pixel, a total grayscale value of the same point of the target object is obtained; based on the total grayscale value and the relationship between the wavelength of the light wave and the transmittance, a centroid spectrum of the same point of the target object is obtained, and then a centroid spectrum of each point of the target object is obtained.

[0139] Step 1020 : Obtain surface information of the target object based on the centroid spectrum of each point of the target object.

[0140] The above-mentioned non-destructive surface measurement method of an object emits excitation light to an object having a photoluminescent material. A linear dichroic mirror is placed in the optical path of the target's probe light, utilizing the characteristics of the linear dichroic mirror: its transmittance increases with increasing wavelength and its reflectance decreases with decreasing wavelength. The linear dichroic mirror is then positioned in the optical path of the target's probe light. A first image sensor is positioned in the transmission optical path of the linear dichroic mirror to obtain a first grayscale image of the target's probe light transmitted by the linear dichroic mirror. A second image sensor is positioned in the reflection optical path of the linear dichroic mirror to obtain a second grayscale image of the target's probe light reflected by the linear dichroic mirror. The first and second grayscale images are processed to obtain a centroid spectrum of each point on the target. Surface information of the target is then obtained based on the centroid spectrum of each point on the target. This non-destructive testing of the target allows surface information of the target having the photoluminescent material to be obtained. Furthermore, surface defect information of the target having the photoluminescent material can be obtained based on this non-destructive testing. In addition, integrating the autofocus system into the PL detection device can simultaneously complete spectral detection and AOI detection items, thereby improving the detection rate and reducing costs.

[0141] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0142] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A non-destructive measuring device for a target surface, characterized in that: include: A first light source is used to emit a first excitation light to a target object; the target object includes a photoluminescent material; a lens, receiving and adjusting the target detection light excited by the first excitation light; a linear dichroic mirror that transmits at least a portion of the target detection light and reflects at least a portion of the target detection light; wherein the transmittance of the linear dichroic mirror increases with increasing wavelength and the reflectance decreases with decreasing wavelength; a first image sensor, arranged in a transmission light path of the linear dichroic mirror, and obtaining a first grayscale image of the target detection light transmitted by the linear dichroic mirror; as well as a second image sensor, arranged in a reflected light path of the linear dichroic mirror, and obtaining a second grayscale image of the target detection light reflected by the linear dichroic mirror; wherein, by performing image processing on the first grayscale image and the second grayscale image, a centroid spectrum of each point of the target object is obtained; And based on the centroid spectrum of each point of the target object, the surface information of the target object is obtained.

2. The non-destructive measuring device for target surface according to claim 1, characterized in that: Also includes: A light homogenizer is located at the emission end of the first light source, and is used to receive the first excitation light emitted by the first light source and perform light homogenization processing on the light intensity of the first excitation light.

3. The target surface non-destructive measurement device according to claim 2, characterized in that: The light homogenizer is a homogenizing optical fiber, and the input end of the homogenizing optical fiber has multiple interfaces, which can receive the first excitation light of different wavelengths.

4. The target surface non-destructive measurement device according to claim 2, characterized in that: Also includes: A collimator is located at the output end of the light homogenizer, and is used to receive the homogenized first excitation light and adjust the emission angle of the first excitation light to be perpendicular to the surface of the target object.

5. The non-destructive measuring device for target surface according to claim 1, characterized in that: Also includes: The second beam splitter prism is disposed between the lens and the linear dichroic mirror and is capable of deflecting the first excitation light.

6. The non-destructive measuring device for target surface according to claim 1, characterized in that: Also includes: The first filter is located on the optical path between the lens and the linear dichroic mirror, and is used to filter out the excitation light reflected by the target and transmit the detection light through the target.

7. The non-destructive measuring device for a target surface according to any one of claims 1 to 6, characterized in that: Also includes: an aperture, located at the emission end of the first light source, capable of blocking part of the light spot of the first excitation light to obtain a second excitation light; a lens, opposite to the aperture, receiving the second excitation light, and collimating the second excitation light to convert divergent light into parallel light; and the lens also receiving a third excitation light and converging the third excitation light; wherein the third excitation light is obtained by reflecting the second excitation light from the target; a second filter, located in the optical path between the lens and the lens, for filtering out the target detection light and transmitting the third excitation light; The third image sensor receives the third excitation light and obtains a spot image of the third excitation light; obtains a defocus amount of the target surface non-destructive measurement device according to the spot image of the third excitation light, and adjusts the distance between the lens and the target based on the defocus amount.

8. The non-destructive measuring device for target surface according to any one of claims 1 to 6, characterized in that: Also includes: a second light source, configured to emit a fourth excitation light to the target object; the wavelength of the fourth excitation light being greater than the wavelength of the first excitation light; an aperture, located at the emission end of the second light source, capable of blocking a portion of the light spot of the fourth excitation light to obtain a fifth excitation light; a lens, opposite to the aperture, receiving the fifth excitation light, and collimating the fifth excitation light to convert divergent light into parallel light; and the lens also receiving the sixth excitation light and converging the sixth excitation light; wherein the sixth excitation light is obtained by the target reflecting the fifth excitation light; a second filter, located in the optical path between the lens and the lens, for filtering out the target detection light and transmitting the fifth excitation light and the sixth excitation light; The third image sensor receives the sixth excitation light and obtains a spot image of the sixth excitation light; obtains the defocus amount of the lens according to the spot image of the sixth excitation light, and adjusts the distance between the lens and the target object based on the defocus amount.

9. The non-destructive measuring device for target surface according to claim 7, characterized in that: Also includes: The first beam splitter prism is disposed between the aperture and the lens and is capable of deflecting the light converged by the lens to the third image sensor.

10. The target surface non-destructive measurement device according to claim 8, further comprising: The third beam splitter prism is arranged on the optical path between the second filter and the lens, and can deflect the fifth excitation light to the lens and deflect the sixth excitation light to the second filter.

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