TWI830680B - Fluorescence detection method - Google Patents

Abstract

A fluorescence detection method including the following steps is provided. Based on a test object, define at least one irradiated area on the test object. According to the at least one irradiated area, correspondingly set an energy accumulation threshold of the at least one irradiated area. Use an excitation light source to irradiate the at least one irradiated area on the test object, so that the test object generates a fluorescence. By the fluorescence, image detection of the test object. When an energy accumulated in the at least one irradiated area reaches the energy accumulation threshold, stop to use the excitation light source to irradiate the irradiated area.

Description

Fluorescence detection method

The present invention relates to a detection system and a detection method, and in particular, to a fluorescence image detection system and a fluorescence detection method.

In traditional visible light detection technology, materials with high reflectivity or high transmittance are not easy to be well displayed by visible light detection. For example, there are materials with high reflectivity such as metal in the object to be tested, making the detection results prone to misjudgment. Alternatively, transparent colloids are not easily visible in visible light detection.

Fluorescence is a phenomenon in which an object absorbs short-wavelength excitation light and emits long-wavelength emitted light. Fluorescence detection uses organic matter in the object to be tested to generate fluorescence, which can provide higher detection quality, so it has become one of the options for automated optical inspection (AOI). For example, the appearance of a transparent colloid can be clearly highlighted through the fluorescence produced by the colloid when irradiated with excitation light.

However, since fluorescence is a very weak light source, it is difficult to mass-produce it under the high production speed requirements of industrial inspection. Moreover, if the irradiation intensity or time of the excitation light is increased in order to increase the intensity of fluorescence, it will cause a photobleaching effect, thereby damaging the object to be measured.

The invention provides a fluorescence image detection system and a fluorescence detection method, which can improve the fluorescence detection effect while avoiding light-induced fading.

An embodiment of the present invention provides a fluorescence image detection system for detecting a fluorescence image of an object to be tested. The fluorescence image detection system includes an excitation light source, a side scanning image capturing device, a filter module and a controller. The excitation light source generates an excitation light to at least one illumination area on the object to be measured, so that the object to be measured generates fluorescence. The area scanning image capturing device receives fluorescence from the object to be tested to obtain a fluorescent image of the object to be tested. The filter module is coupled between the area scanning image capturing device and the object to be measured to filter out the excitation light and allow the fluorescent light to pass through the filter module. The controller is coupled to the area scanning image capturing device to receive and detect the fluorescent image.

An embodiment of the present invention provides a fluorescence detection method, which includes the following steps. Based on an object to be measured, at least one irradiation area is defined on the object to be measured. According to the at least one irradiation area, the energy accumulation threshold of the at least one irradiation area is correspondingly set. An excitation light source is used to illuminate at least one illumination area on the object to be tested, so that the object to be tested generates fluorescence. Through fluorescence, the object to be tested is image-detected. Wherein, when the accumulated energy of at least one irradiation area reaches an energy accumulation threshold, the irradiation area with the excitation light source is stopped.

Based on the above, in one embodiment of the present invention, since the fluorescence image detection system and the fluorescence detection method control the time during which the excitation light irradiates the irradiation area of the object to be measured according to the energy accumulation threshold, the fluorescence image detection system and The fluorescence detection method can improve the fluorescence detection effect while avoiding light-induced fading. Furthermore, due to the use of a large-area array area scanning image capture device, the fluorescence image detection system of the embodiment of the present invention can meet the high-speed detection requirements compared to the use of a line array image sensor.

Please refer to FIGS. 1-3. A fluorescence image detection system 100 according to an embodiment of the present invention is used to detect a fluorescence image of an object S to be tested. The fluorescence image detection system 100 includes an excitation light source 110, a surface scanning image capturing device 120, a filter module 140A and a controller 130. In this embodiment, including but not limited to, the object S to be tested is, for example, a printed circuit board, a wafer, or other objects containing organic matter, and the organic matter is, for example, transparent colloid on the printed circuit board or contaminants on the wafer.

In this implementation, the excitation light source 110 is used to emit excitation light EL. The excitation light source 110 may be a light-emitting diode (LED) light source, a laser diode (Laser Diode) light source, or other suitable light sources. The excitation light EL can be ultraviolet light, blue light, white light or other colored light. In this implementation, the excitation light source 110 generates excitation light EL onto at least one illumination area IR of the object S, so that the object S generates fluorescence F. For example, the object S to be tested can convert ultraviolet light into blue light or can convert blue light into green light, but the invention is not limited thereto.

In this embodiment, the area scanning image capturing device 120 receives the fluorescence F from the object S to obtain the fluorescence image of the object S. The area scanning image capturing device 120 can be a light sensor such as a complementary metal-oxide semiconductor (CMOS), a charge coupled device (CCD) or a photodiode (photodiode), but The present invention is not limited to this.

In one embodiment, the controller 130 includes, for example, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a programmable controller, a programmable The present invention is not limited to a programmable logic device (PLD) or other similar devices or combinations of these devices. Furthermore, in one embodiment, each function of the controller 130 may be implemented as multiple program codes. These program codes will be stored in a memory unit, and the controller 130 will execute these program codes. Alternatively, in one embodiment, each function of controller 130 may be implemented as one or more circuits. The present invention is not limited to using software or hardware to implement each function of the controller 130 .

In this embodiment, the controller 130 is coupled to the excitation light source 110 or to the area scanning image capture device 120 to receive and detect the fluorescent image. The controller 130 controls the excitation light source 110 to continuously emit the excitation light EL within the energy accumulation threshold, and stops irradiating the irradiation area IR with the excitation light source 110 when the energy accumulated in the irradiation area IR reaches the energy accumulation threshold. In this embodiment, stopping the irradiation of the illumination area IR with the excitation light EL is, for example, turning off the excitation light source 110 . Alternatively, an aperture is provided on the transmission path of the excitation light EL, and the controller 130 controls the aperture to cause the irradiation area IR to be irradiated with the excitation light EL or to stop being irradiated.

In one embodiment, the object S to be tested is a photoresist, including but not limited to, the organic substance is phenolic resin. The irradiation area IR is, for example, a 10 mm ² area on the object S. When the excitation light EL is near-ultraviolet light and is irradiated to the irradiation area IR, photofading will occur after the energy is accumulated to 50 mj/ ^mm2 . If the excitation light EL is irradiated to the irradiation area IR with an intensity of 10 mj/ ^mm2 per second, this energy accumulation can correspond to 5 seconds. In other words, cumulative irradiation may cause photofading of the organic matter in the irradiation area IR of the object S after about 5 seconds. In this embodiment, including but not limited to, 80% of the energy that causes photofading can be set as the energy accumulation threshold.

In this embodiment, the pixels of the area scanning image capturing device 120 are, for example, 14,000×10,000; therefore, the area scanning image capturing device 120 has an exposure time that is 10,000 times longer than that of general line array scanning. In one embodiment, the total pixels of the area scan image capture device 120 may be the upper limit of the process. Furthermore, the signal-to-noise ratio can be improved by increasing the exposure time of the area scan image capture device 120. For example, the exposure time of the area scan image capture device 120 can be increased to approximately greater than or equal to the time corresponding to the energy accumulation threshold. Therefore, when fluorescent light is usually a weak light source, by using a large-area array area scanning image capture device and by increasing the exposure time, compared to using a line array image sensor, the fluorescent light according to embodiments of the present invention can The optical image detection system 100 can meet the requirements of high-speed detection.

In this embodiment, the excitation light source 110 includes multiple light guide fiber light sources with different illumination directions. As shown in Figure 2, the light source of the light guide fiber is used to irradiate the excitation light EL to the object S in four diagonal directions. In this way, in addition to providing a uniform light source, the energy required to supply fluorescent light can be increased. In another embodiment, the excitation light source may include an annular light source.

In this embodiment, the fluorescence image detection system 100 further includes a filter module 140A. The filter module 140A is coupled between the area scanning image capturing device 120 and the object S, and is used to filter out the excitation light EL and allow the fluorescent light F to pass through the filter module 140A. In one embodiment, the fluorescence image detection system 100 further includes another filter module 140B. The filter module 140B is coupled between the excitation light source 110 and the object S on the transmission path of the excitation light EL, so as to pass the excitation light EL and filter the remaining colored light.

In one embodiment, the fluorescence image detection system 100 further includes a spectroscope 200 . The beam splitter 200 is used to reflect the excitation light EL and transmit the fluorescent light F. The spectroscope 200 is coupled between the filter module 140B and the object S on the transmission path of the excitation light EL, and is coupled between the filter module 140A and the object S on the transmission path of the fluorescent light F.

In one embodiment, the fluorescence image detection system 100 further includes an objective lens 300 . The beam splitter 200 is disposed between the objective lens 300 and the filter module 140A.

In this embodiment, the fluorescence image detection system 100 further includes a zoom lens 400 . The controller 130 is coupled to the zoom lens 400 so that the fluorescence image detection system 100 can adjust the magnification of the lens according to the shape of the object S to be tested.

In this embodiment, the fluorescence image detection system 100 further includes a mobile stage 500 . The controller 130 is coupled to the mobile stage 500 so that the fluorescence image detection system 100 can adjust the relative position between the fluorescence image detection system 100 and the object S to be measured, thereby adjusting the position of the irradiation area IR.

In this embodiment, the fluorescence image detection system 100 further includes a leading focus module 600 . Among them, the leading focusing method is to detect the Z depth of the N+1 position at the N position before measuring the focus at the N+1 position, and then adjust the Z depth when the camera moves from the N position to the N+1 position. Focus to reduce the time of finding the next position to focus. The controller 130 is coupled with the leading focus module 600 so that the fluorescent image detection system 100 can instantly respond to the correct focus plane through focus feedback, thus helping to improve detection quality and reduce detection time.

Please refer to Figure 4. A fluorescence detection method according to an embodiment of the present invention includes the following steps. Step S100: Based on an object S, at least one irradiation area IR is defined on the object S. Step S110, correspondingly set the energy accumulation threshold of at least one irradiation area IR according to the at least one irradiation area IR. Step S120: Use an excitation light source 110 to illuminate at least one illumination area IR on the object S, so that the object S generates fluorescence F. Step S130: Using the fluorescent light F, the object S is image-detected. When the energy accumulated in at least one illumination region IR reaches the energy accumulation threshold, the excitation light source 110 stops irradiating the illumination region IR.

In this embodiment, the fluorescence detection method further includes the following steps. The unit irradiation energy provided by the excitation light source 110 is corrected. For example, an energy detector is used to first determine the unit irradiation energy of the excitation light source 110 (such as Joules/second or millijoules/second).

In this embodiment, the above step of irradiating at least one irradiation area IR on the object S by the excitation light source 110 includes: recording the energy accumulation state of the at least one irradiation area IR.

In this embodiment, the above step of setting the energy accumulation threshold of at least one irradiation region IR includes: setting the energy accumulation threshold according to the material type of the at least one irradiation region IR.

To sum up, in an embodiment of the present invention, the fluorescence image detection system and the fluorescence detection method control the excitation light to illuminate the object to be measured according to the established irradiation area and the energy accumulation threshold corresponding to the irradiation area. Therefore, the fluorescence image detection system and fluorescence detection method can improve the fluorescence detection effect while avoiding light-induced fading. Furthermore, due to the use of a large-area array area scanning image capture device, the fluorescence image detection system of the embodiment of the present invention can meet the high-speed detection requirements compared to the use of a line array image sensor.

100: Fluorescence image detection system 110: Excitation light source 120: Area scanning image capture device 130:Controller 140A, 140B: Filter module 200: Beam splitter 300:Objective lens 400:Zoom lens 500:Mobile carrier 600: Leading focus module EL: excitation light F: Fluorescence IR: irradiation area S: object to be tested S100, S110, S120, S130: steps

Figure 1 is a schematic optical path diagram of a fluorescence image detection system according to an embodiment of the present invention. Figure 2 is a three-dimensional schematic diagram of a fluorescence image detection system according to an embodiment of the present invention. Figure 3 is a schematic diagram of establishing multiple irradiation areas for the object to be measured. Figure 4 is a flow chart of a fluorescence detection method according to an embodiment of the present invention.

100: Fluorescence image detection system

110: Excitation light source

130:Controller

140A, 140B: Filter module

200: Beam splitter

300:Objective lens

EL: excitation light

F: Fluorescent

S: object to be tested

Claims (4)

A fluorescence detection method, including: Based on an object to be measured, at least one irradiation area is defined on the object to be measured; According to the at least one irradiation area, correspondingly set the energy accumulation threshold of the at least one irradiation area; Illuminating the at least one illumination area on the object to be measured with an excitation light source to cause the object to be measured to generate fluorescence; and Through the fluorescence, the object to be detected is image-detected; When the accumulated energy of the at least one irradiation area reaches the energy accumulation threshold, the excitation light source stops irradiating the at least one irradiation area. The fluorescence detection method as described in claim 1 further includes: Calibrate the unit irradiation energy provided by the excitation light source. The fluorescence detection method according to claim 1, wherein the step of irradiating the at least one irradiation area on the object to be measured with the excitation light source includes: Record the energy accumulation status of the at least one irradiation area. The fluorescence detection method according to claim 1, wherein the step of setting the energy accumulation threshold of the at least one irradiation area includes: The energy accumulation threshold is set according to the material type of the at least one irradiation area.

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