TWI542869B - Automatic dimming method for optical detection and its optical inspection machine - Google Patents

Description

Automatic dimming method for optical detection and optical inspection machine thereof

The invention relates to an automatic dimming method for optical detection and an optical detecting machine thereof, and more particularly to an automatic optimized automatic dimming for illuminating light source configuration of different kinds of circuit boards to be tested. Method and optical inspection machine using the automatic dimming method.

Automated Optical Inspection (AOI) plays a pivotal role in the detection of soft or hard boards. For example, in the manufacturing process of various boards, precise automatic optical inspection is required to distinguish the advantages and disadvantages of the board and to carry out quality control.

The automatic optical inspection is performed by the operation of the optical inspection machine. During the detection process, the light is irradiated onto the circuit board, and then the image of the printed circuit board is captured by the imaging device to determine the flaw, and thus The quality of the light source provided by the illumination device on the optical inspection machine has a considerable influence on the detection. Once the quality of the light source is not good or the configuration is different from the previous one, the detection result will be shifted due to the detection data. The result is inaccurate or the quality of the product is unstable.

Traditionally, the illumination configuration of the light source device on the optical inspection machine (ie, the intensity control of each illumination light) is performed manually according to the rule of thumb or directly applying the illumination configuration of a similar circuit board. However, such setting Not only is it not controlled by the normalization process, but it is also likely to cause the generation of defective products due to human error. Once the type of the circuit board to be tested needs to be constantly changed, the manual adjustment is not only time-consuming but also time-consuming. It is impossible to homogenize the testing standards between the machines. Such shortcomings often result in products that fail to maintain stable product quality.

It is an object of the present invention to maintain a stable board inspection quality.

Another object of the present invention is to automatically perform automatic dimming of light source illumination configurations for various types of circuit boards.

In order to achieve the above and other objects, the present invention provides an automatic dimming method for optical detection, which is an optical detecting machine for automatically adjusting an illumination source between different types of circuit boards to be tested, including: picking and replacing The image data on the circuit board to be tested after the type; the dimming area setting step is to set at least one dimming area and its corresponding type according to the image data, the type of the dimming area includes a metal type and a text type. And at least two of the three types of solder mask; the dimming step is performed by lateral illumination and lateral illumination and forward illumination, and the selected one is selected The type of dimming area is a reference, and based on each of the illumination configurations, the image data of the selected type of dimming area and the pre-stored brightness threshold value data based on the selected type of dimming area are compared. Next, adjusting the intensity of the illumination light, and then according to the image data of any two types of dimming regions taken under the configuration that the side illumination light and the forward illumination light are simultaneously irradiated Value, to obtain the degree of difference in luminance corresponding to a selected one of the irradiation light adjustment configuration; and storing the irradiated light adjustment configuration for detecting the same type of circuit board.

In an embodiment of the present invention, the dimming step includes: performing a sidelight adjusting step to provide lateral illumination light that is laterally incident on the circuit board to be tested, and the initial illumination intensity adjustment is selected. In the dimming area of the type, adjust to the value of the image brightness in the captured image to reach a first target interval value to obtain the set value of the side light illumination configuration; perform the positive light adjustment step to maintain the side Under the illumination of the set value of the light illumination configuration, the forward illumination light that is positively incident on the circuit board to be tested is further provided, and the initial illumination intensity of the forward illumination light is adjusted in the selected type of dimming region. Adjusting the brightness value of the image in the captured image to a second target interval value to obtain a set value of the first positive light illumination configuration, and configuring the side light illumination and the first positive light Under the set value of the illumination configuration, the brightness value of the image data between the two types of dimming areas is obtained, and the corresponding brightness difference degree is obtained; and the second positive light adjustment step is performed, and the side light illumination configuration is maintained. Set value Under illumination, the forward illumination light is further adjusted to provide a forward illumination light that is higher than a set value of the first positive illumination illumination configuration, the further adjustment of the forward illumination light being within a selected type of dimming region, Adjusting to the value of the image brightness in the captured image to reach a third target interval value, to obtain a set value of the second positive light illumination configuration, and the side light illumination configuration and the second positive light Under the setting value of the illumination configuration, the brightness value of the image data between the two types of dimming areas is extracted, and the corresponding brightness difference degree is obtained, and the illumination light adjustment configuration is selected.

In an embodiment of the present invention, in the dimming step, after the second positive light adjustment step and before the selection of the illumination light adjustment configuration, the method further includes: turning off all illumination configurations; performing the second round side illumination The adjusting step is to provide lateral illumination light that is laterally incident on the circuit board to be tested, and the initial illumination intensity is adjusted in the selected type of dimming region to adjust the image brightness in the currently captured image. The value reaches a second round of the first target interval value to obtain a set value of the second round side light illumination configuration; and the second round of the positive light adjustment step is performed to maintain the set value of the second round side light illumination configuration Under the illumination, the positive illumination light that is positively incident on the circuit board to be tested is further provided, and the initial illumination intensity of the forward illumination light is adjusted in the selected type of dimming region, and is adjusted to be captured at the present time. The image brightness value in the image reaches a second round of the second target interval value to obtain a set value of the second round of the first positive light illumination configuration, and the second wheel side light illumination configuration and the second The set value of the first positive illumination of the wheel The brightness value of the image data between the two types of dimming areas is obtained, and the corresponding brightness difference degree is obtained; and the second round of the second positive light adjusting step is performed, and the second side first side light irradiation configuration is maintained. Under the illumination of the set value, the forward illumination light is further adjusted to provide a forward illumination light higher than a set value of the first positive illumination illumination configuration of the second round, and the further adjustment of the forward illumination light is based on the selected type In the dimming area, adjusting the brightness value of the image in the captured image to a second round of the third target interval value to obtain a set value of the second round of the second positive illumination configuration, and The brightness of the image data between the two types of dimming areas is obtained by the side light illumination configuration and the set value of the second positive light illumination configuration of the second round, and the corresponding brightness difference degree is obtained to select the The illumination light adjustment configuration, wherein the maximum value of the first target interval value of the second round is greater than the maximum value of the first target interval value, and the second target second target interval value is equal to the second target interval value. The second round Interval equal to the target value based third target value range.

In an embodiment of the present invention, the type of the dimming area is a metal type, a text type, a bright area type of the solder resist layer, and a dark area type of the solder resist layer, and the illumination light adjustment group is selected. In the step of the state, the set value of the side light illumination configuration and the first positive light illumination configuration, the side light illumination configuration and the set value of the second positive light illumination configuration, the second wheel side The light illumination configuration and the set value of the first positive light illumination configuration of the second round, the second wheel side light illumination configuration and the set value of the second round of the second positive illumination configuration, the determination among the four One is used as the illumination light adjustment configuration, wherein the order of the determination rules is performed in the following order, and when the results of the degree of difference are the same, the next rule is required to be determined, and the difference degree is different when the result of the difference degree is different. The large configuration setting value is the illumination light adjustment configuration; first, the brightness difference between the bright area type of the solder mask and the dark area type of the solder resist layer; second, the brightness difference between the metal type and the text type Degree; third, the type of bright area of the solder mask The luminance difference between the maximum value of the degree of the dark region of the solder resist layer type and text type; and fourth, the luminance difference between the maximum value of the degree of the dark area and bright area type solder resist layer and the metal type of the solder resist layer type.

In an embodiment of the present invention, the selected type of the dimming area is the metal type, and the image corresponding to at least one of the dimming areas is captured based on each illumination configuration. The data and the comparison based on the pre-stored luminance threshold data of the selected type of dimming region are compared using the image data of the red wavelength segment in the image data.

In an embodiment of the present invention, in the dimming region setting step, the at least one dimming region and its corresponding type are set based on a user's delimitation.

In order to achieve the above and other objects, the present invention further provides an optical detecting machine comprising an illumination source group, a camera group and a control group, wherein the control group controls the light intensity adjustment of the illumination source group and receives the camera. The image data captured by the group is operated by the optical inspection machine to automatically adjust the illumination source between different types of circuit boards to be tested, and the control group operates to perform the automatic dimming method as described above.

Therefore, the present invention performs corresponding dimming processing through the type setting of each dimming area and the sequential illumination of the two kinds of illumination configurations of side light, side light plus positive light, which not only makes the optical detecting machine disclosed in the present invention correct. Different types of boards to be tested are automatically optimized for the configuration of the illumination source, so that the boards to be inspected can be detected under uniform conditions, thereby maintaining the uniform quality of the board.

In order to fully understand the objects, features and advantages of the present invention, the present invention will be described in detail by the following specific embodiments and the accompanying drawings.

1 and FIG. 2, FIG. 1 is a flowchart of an automatic dimming method in an embodiment of the present invention, and FIG. 2 is a schematic diagram of an optical detecting machine in an embodiment of the present invention.

The optical inspection machine includes an illumination source group (including a lateral illumination light source 201 and a forward illumination light source 203), an imaging group 300, and a control group 100. The control group 100 is connected to the camera group 300 and the illumination source group (not shown) to control the light intensity adjustment of the illumination source group and receive the image data captured by the camera group 300 on the optical inspection machine. The control group 100 is operable to perform the automatic dimming method disclosed herein when performing automatic adjustment of the illumination source between different types of circuit boards 500 to be tested. The forward illumination light source 203 shown in FIG. 2 can be operated to avoid obscuring the imaging range of the imaging group 300 based on the arrangement relationship with the two sides of the illumination light source 201 on the same plane.

The automatic dimming method in an embodiment of the present invention mainly captures image data of a circuit board to be tested after replacing the type for setting the dimming area and its corresponding type, wherein the dimming area and its corresponding type are set. The user can specify the dimming area and select the corresponding type, or the image data acquired by the control group 100 according to the dimming and the image features of each type on the circuit board (eg, metal lines). The upper reflection will have the highest brightness under the image of the red wavelength range) to automatically identify the dimming areas corresponding to various types on the circuit board, and select the area with better image quality for the subsequent dimming process. get on. Subsequent embodiments of the present invention are exemplified by the manner manually selected by the user.

As shown in FIG. 1, the automatic dimming method in an embodiment of the present invention is performed as follows:

First, in step S100, it is determined whether or not a replacement command for detecting a different type of circuit board is received. If YES, the process proceeds to the next step S200. If NO, the process proceeds to the next step S101 to maintain the current illumination configuration.

Next, in step S200, the type setting of each dimming area on the circuit board to be tested after replacing the type of the circuit board is received. The type setting here is defined according to various types of the surface of the board, and includes, for example, a metal type as a wire, a type of text printed by a character, and a solder resist type of various color solder resist layers. Generally speaking, the metal lines formed on the circuit board are covered with an organic solder resist (OSP), or directly tinned or formed by chemical nickel gold; the printed characters on the board are white, black or other colors. Etc.; the solder mask is green, blue, white, red, etc. After the operator replaces the circuit board to be automatically dimmed, the image data captured by the camera group 300 is displayed on the screen of the control group 100 (not shown), and then input through the control group 100. Interfaces (eg, mouse, keyboard, etc.) to select each of the dimming regions that are to be dimmed, such that the dimming regions are set in the control group 100, and the dimming regions are The type of setting (such as the metal type, text type or solder mask type mentioned above).

Wherein, the setting of the dimming area and its type is at least two sets, that is, at least two of the metal type, the text type and the solder mask type, for the dimming step. For example, the type of solder mask is usually divided into the bright area type of the solder resist layer (the metal wiring layer under the solder resist layer) and the dark area type of the solder resist layer (the metal trace layer is not under the solder resist layer), so The dimming step is to enable at least the image data between the two to be clearly identified, that is, the brightness value of the image data between different dimming area types must be distinguished by the detection system based on the preset target value. In turn, the dimming reference is consistent, and the board under test can be detected under uniform conditions. In addition, for example, general circuit detection must usually be set using at least metal type and solder mask type, because the board inspection is usually configured correctly for the metal line, and the system must clearly identify the board. The metal line depends on the image difference between the area next to the metal line (usually the type of solder mask) and the metal line. The larger the difference, the easier it is to identify. However, the above is merely an example, and is not a limitation. The detection of the board may also be set for other types without departing from the scope of the present invention.

Next, in step S300, a dimming step is performed. This step is performed by the first type of simple lateral illumination and the second type of lateral illumination combined with the forward illumination. Under the illumination of the two configurations, the type of dimming area selected has been selected. This is done for the benchmark (usually the metal type, described below in terms of metal type). That is, the image data of the dimming area corresponding to the metal type captured under the current illumination configuration is dimmed according to the pre-stored brightness threshold value standard data of the metal type dimming area. In other words, the intensity of the illumination light is adjusted within the preset adjustment range in comparison with the standard data of the luminance threshold value. Then, according to the brightness values of the image data between the two types of dimming regions (such as the metal type and the solder mask type) taken under the configuration in which the lateral illumination light and the forward illumination light are simultaneously irradiated, the corresponding values are obtained. The degree of brightness difference is selected and an illumination light is selected to adjust the configuration. .

For example, in the case of a metal-type dimming area, in order to clearly identify the metal line in the captured image, the minimum light intensity of the metal reflected light in the area is higher than other types of adjustment. The maximum reflected light intensity value of the light region is preferably determined by the red light wavelength band. For another example, the white text can be clearly identified from the solder mask. When the green solder mask is used, the light intensity value of the blue light band should be used. When the blue solder resist layer is used, the green color should be green. The light intensity value of the optical band is checked. When matching the red solder mask, the light intensity value of the green light (priority) or blue light band is used to check; the black text can be clearly recognized from the solder resist layer. When matching with the green solder mask, check the light intensity value of the green (priority) or blue light band. When using the blue solder mask, check the light intensity value of the blue light band. When paired with the red solder mask It should be viewed in light intensity values in the green (priority) or blue light bands.

Next, in step S400, the illumination light adjustment configuration is stored for the detection of the same type of circuit board.

Accordingly, the automatic dimming of the present invention is to select the maximum degree of brightness difference between different types of dimming regions under the set values of the sidelight illumination configuration and the positive light illumination configuration (ie, the value of the phase difference) The absolute value is the largest) down to determine the illumination adjustment configuration.

Next, please refer to FIG. 3(a), which is a flowchart of an automatic dimming method in another embodiment of the present invention. The invention is based on the metal line as the main item of the circuit board detection, and further performs the following steps in the dimming step to obtain an illumination light adjustment configuration that can optimize the captured image of the metal line.

First, the sidelight adjustment step S301 is performed before the illumination is not provided, and the lateral illumination light 220 that is laterally incident on the circuit board to be tested is provided, and the initial illumination intensity is adjusted according to the selected type of dimming. In the area (for example, metal type), the lateral illumination light is adjusted until the brightness value of the image captured in the current image reaches a first target interval value (in the case of the metal type, the first target interval value may be, for example, For the range of 120 to 140, the value is in the range of 0 to 255. In order to obtain the set value of the side illumination configuration (ie, the output value of the lateral illumination to be adjusted to meet the previous conditions).

Then, the positive light adjustment step S302 is performed, and under the illumination of maintaining the set value of the side light illumination configuration, the forward illumination light that is positively incident on the circuit board to be tested is further provided, and the initial illumination intensity of the forward illumination light is adjusted. Adjusting to the dimming area of the selected type, adjusting the brightness value of the image in the captured image to a second target interval value (in the case of the metal type, the second target interval value may be, for example, 160~180, this value is based on the brightness value range of 0~255. This value refers to the value obtained by the superposition of the sidelight illumination and the positive illumination, to obtain the setting of the first positive illumination configuration. Value (ie, the output value of the forward illuminating light adjusted to meet the previous conditions), and taking any two types of dimming regions under the sidelight illumination configuration and the set value of the first positive illuminating configuration The brightness value of the image data between the two is obtained, and the corresponding brightness difference degree is obtained.

After the foregoing two steps, a set of positive and side light settings are found to be used as the illumination light adjustment configuration. Preferably, as shown in FIG. 3(a), further comprising: a positive second adjustment step S303, adjusting the forward illumination while maintaining the set value of the side illumination configuration. Light is provided to provide a forward illumination light that is higher than a set value of the first positive illumination configuration, the further adjustment of the forward illumination light being within a selected type of dimming region, adjusted to be captured in the current image The image brightness value reaches a third target interval value (in the case of the metal type, the second target interval value can be, for example, 180 to 200, and the value is in the range of 0 to 255. Refers to the value obtained by superposition of side light illumination and positive light illumination) to obtain a set value of a second positive light illumination configuration, and in the configuration of the side light illumination configuration and the second positive light illumination configuration Under the set value, the brightness value of the image data between the two types of dimming areas is obtained, and the corresponding brightness difference degree is obtained.

In the program for selecting the illumination light adjustment configuration, for example, the type of the dimming area is a metal type, a text type, a bright area type of the solder resist layer, and a dark area type of the solder resist layer. The step of selecting the illumination light adjustment configuration is performed from the sidelight illumination configuration and the set value of the first positive illumination illumination configuration, the side illumination illumination configuration, and the set value of the second positive illumination illumination configuration. One of the two is determined as the illumination light adjustment configuration, wherein the order of the determination rules is performed in the following order, and when the result of the difference degree is the same, the next rule is required to be determined, and the result of the degree of difference At different times, the configuration setting value with a large degree of difference is adjusted according to the illumination light; first, the degree of brightness difference between the bright area type of the solder resist layer and the dark area type of the solder resist layer; second, the metal type and The degree of brightness difference between text types; third, the type of bright area of the solder mask and the difference between the maximum value of the dark area type of the solder resist layer and the brightness of the text type; and the fourth, the metal type and the brightness of the solder resist layer Zone type and anti-welding The degree of brightness difference between the maximum values of the dark area types of the layers.

For example, when the sidelight illumination configuration and the set value of the first positive illumination configuration are below, the value under the first rule specification is 10; when the sidelight illumination configuration and the second positive illumination Under the configured set value, the value under the first rule specification is also 10, that is, both are the same (or different within a certain range), and then enter the second rule to judge. When the side light illumination configuration and the set value of the first positive light illumination configuration are below, the value under the second rule specification is 32; when the side light illumination configuration and the second positive light illumination configuration are set Below the value, the value under the second rule specification is also 30, that is, there is a larger one. According to this, the illumination light adjustment configuration is selected as "the side light illumination configuration and the first positive light illumination group. The set value of the state, that is, the configuration setting with a large difference is the adjustment configuration of the illumination light.

Next, please refer to FIG. 3(b), which is a flowchart of an automatic dimming method in still another embodiment of the present invention. Following the step of FIG. 3(a), the second round of dimming step is performed, and after the positive second adjustment step S303 and before the illumination light adjustment configuration is recorded (step S400), Step S310: Turn off all illumination configurations; Step S311: Perform a second round side light adjustment step to provide lateral illumination light that is laterally incident on the circuit board to be tested, and the initial illumination intensity adjustment is selected. In the dimming area of the type, the brightness value of the image in the captured image reaches a second target first target interval value and the maximum value of the second target first target interval value is greater than the first target The maximum value of the interval value (in the case of the metal type, the first target interval value in the second round can be, for example, 140 to 160. This value is in the range of 0 to 255. The value refers to the side light. The value obtained by superimposing under illumination and under normal illumination is obtained to obtain a set value of the second wheel side illumination configuration. Step S312, performing a second round of the first positive light adjustment step, under the illumination of maintaining the set value of the second round side light illumination configuration (ie, the second round of the second target interval value is equal to the second target interval value Providing a forward illumination light that is positively incident on the circuit board to be tested, and the initial illumination intensity of the forward illumination light is adjusted in the selected type of dimming region, and is adjusted to be captured in the current image. The brightness value of the image reaches a second target interval value of the second round (in the case of the metal type, the second target interval value of the second round may be 160 to 180, for example, the value is in the range of 0~ 255 is an example. This value refers to the value obtained by superposition of side light illumination and positive light illumination) to obtain a set value of the first positive illumination illumination configuration of the second round, and the second round side illumination Under the configuration and the set value of the first positive light illumination configuration of the second round, the brightness value of the image data between the two types of dimming areas is extracted, and the corresponding brightness difference degree is obtained. Step S313, performing a second round of the second positive light adjustment step, under the illumination of maintaining the set value of the second round of the first side light illumination configuration (ie, the second round of the third target interval value is equal to the third target The interval value) further adjusts the forward illumination light to provide a forward illumination light that is higher than a set value of the first positive illumination configuration of the second round, and the further adjustment of the forward illumination light is based on the selected type of adjustment In the light region, the brightness value of the image in the image captured in the current image is adjusted to a value of the third target interval of the second round (in the case of the metal type, the second target value of the third target interval may be, for example, 180~200, this value is based on the brightness value range of 0~255. This value refers to the value obtained by the superposition of the side light and the positive light, to obtain a second round of the second positive illumination group. The set value of the state, and in the set configuration value of the side light illumination configuration and the second positive light illumination configuration of the second round, extract the brightness value of the image data between the two types of dimming regions, and obtain corresponding values The degree of brightness difference.

The maximum value of the first target interval value of the second round is greater than the maximum value of the first target interval value, and the maximum value of the second target second interval value may be equal to or greater than the second target second target interval. The maximum value of the value, the maximum value of the third target interval value of the second round may be equal to or greater than the maximum value of the third target interval value of the second round. Preferably, the maximum value of the second target interval value of the second round is equal to the maximum value of the second target interval value of the second round (or the same range interval), and the maximum value of the second target third interval value is equal to The maximum value of the third target interval value of the second round (or the same range interval).

Similarly, the type of the dimming area is, for example, a metal type, a text type, a bright area type of the solder resist layer, and a dark area type of the solder resist layer, and in the step of selecting the illumination light adjustment configuration. And the setting value of the side light illumination configuration and the first positive light illumination configuration, the side light illumination configuration and the set value of the second positive light illumination configuration, and the second wheel side illumination configuration And the set value of the first positive light illumination configuration of the second round, the second wheel side light illumination configuration, and the set value of the second round of the second positive light illumination configuration, one of the four is determined as the The illumination light adjustment configuration, wherein the order of the determination rules is performed in the following order, and when the result of the difference degree is the same, the next rule is required to be determined, and when the result of the difference degree is different, the configuration with a large degree of difference is adopted. The set value is the illumination light adjustment configuration: first, the degree of brightness difference between the bright area type of the solder resist layer and the dark area type of the solder resist layer; second, the brightness between the metal type and the text type Degree of difference; third, the type of bright area of the solder mask and the difference between the maximum value of the dark area type of the solder resist layer and the brightness of the text type; and the fourth type, the type of the metal and the bright area of the solder resist layer and solder resist The degree of brightness difference between the maximum values of the dark area types of the layers.

In addition, for the metal type dimming region, image data corresponding to one of the at least one dimming region captured under the current illumination configuration, and based on the selected type dimming region In the comparison of the pre-stored luminance threshold data, the image data of the "red wavelength range" in the image data is compared.

In summary, the present invention utilizes the light intensity values represented in the captured images to perform automatic dimming, and can optimize for different types of regions, so that the tested circuit boards can be detected under uniform conditions, and further Can maintain the quality of the board is uniform.

The invention has been described above in terms of the preferred embodiments, and it should be understood by those skilled in the art that the present invention is not intended to limit the scope of the invention. It should be noted that variations and permutations equivalent to those of the embodiments are intended to be included within the scope of the present invention. Therefore, the scope of protection of the present invention is defined by the scope of the patent application.

100‧‧‧Control Group
201‧‧‧ lateral illumination light source
220‧‧‧ lateral illumination
203‧‧‧ Forward illumination source
300‧‧‧ camera group
500‧‧‧Device board to be tested
S100~S400‧‧‧Steps

1 is a flow chart of an automatic dimming method in an embodiment of the present invention. Fig. 2 is a schematic view showing an optical detecting machine in an embodiment of the present invention. FIG. 3(a) is a flowchart of an automatic dimming method in another embodiment of the present invention. FIG. 3(b) is a flowchart of an automatic dimming method in still another embodiment of the present invention.

S100~S400‧‧‧Steps

Claims (9)

An automatic dimming method for optical detection is an automatic adjustment of an illumination source between different types of circuit boards to be tested by an optical inspection machine, comprising: capturing an image on a circuit board to be tested after replacing the type The dimming area setting step is to set at least one dimming area and a corresponding type according to the image data, the type of the dimming area includes at least one of a metal type, a text type and a solder mask type. The dimming step is performed by two types of illuminations of lateral illumination and lateral illumination and forward illumination, based on the type of selected dimming region, and based on each Adjusting the intensity of the illumination light based on the image data of the selected type of dimming area captured by the illumination configuration and the pre-stored brightness threshold value data according to the selected type of dimming area, and then according to the side Obtaining a corresponding brightness difference degree between the brightness values of the image data between the two types of dimming regions captured by the configuration of the illumination light and the forward illumination light simultaneously. Irradiating a predetermined light adjustment configuration; and storing the irradiated light adjustment configuration for detecting the same type of circuit board. The automatic dimming method of claim 1, wherein the dimming step comprises: performing a sidelight adjusting step of providing lateral illumination light that is laterally incident on the circuit board to be tested, and an initial illumination intensity thereof. The adjustment is performed in the dimming area of the selected type, and is adjusted until the brightness value of the image in the captured image reaches a first target interval value to obtain the set value of the side light illumination configuration; In the step of maintaining the set value of the side light illumination configuration, further providing forward illumination light that is positively incident on the circuit board to be tested, and the initial illumination intensity of the forward illumination light is adjusted according to the selected type. In the dimming area, adjust to the brightness value of the image in the captured image to reach a second target interval value, to obtain a set value of the first positive light illumination configuration, and configure the side light illumination configuration And the set value of the first positive light illumination configuration, extracting the brightness value of the image data between the two types of dimming areas, obtaining the corresponding brightness difference degree; and performing the second positive light adjustment step, maintaining the Side light Under the illumination of the set value of the illumination configuration, the forward illumination light is further adjusted to provide a forward illumination light that is higher than the set value of the first positive illumination illumination configuration, and further adjustment of the forward illumination light is selected In the dimming area of the type, adjusting the brightness value of the image in the captured image to a third target interval value to obtain a set value of the second positive light illumination configuration, and in the side light illumination group And the set value of the second positive light illumination configuration, the brightness value of the image data between the two types of dimming areas is obtained, and the corresponding brightness difference degree is obtained, and the illumination light adjustment configuration is selected. The automatic dimming method according to Item 2, wherein the type of the dimming area is a metal type, a text type, a bright area type of a solder resist layer, and a dark area type of a solder resist layer, and The step of selecting the illumination light adjustment configuration is performed from the sidelight illumination configuration and the set value of the first positive illumination illumination configuration, the side illumination illumination configuration, and the set value of the second positive illumination illumination configuration. One of the two is determined as the illumination light adjustment configuration, wherein the order of the determination rules is performed in the following order, and when the result of the difference degree is the same, the next rule is required to be determined, and the result of the degree of difference At different times, the configuration setting value with a large degree of difference is adjusted according to the illumination light; first, the degree of brightness difference between the bright area type of the solder resist layer and the dark area type of the solder resist layer; second, the metal type and The degree of brightness difference between text types; third, the type of bright area of the solder mask and the difference between the maximum value of the dark area type of the solder resist layer and the brightness of the text type; and the fourth, the metal type and the brightness of the solder resist layer Area type and solder mask The luminance difference between the maximum value of the degree of the dark region of type. The automatic dimming method of claim 2, wherein in the dimming step, after the second positive light adjustment step and before the selecting the illumination light adjustment configuration, the method further comprises: turning off all illumination configurations; Performing a second round of sidelight adjustment step is to provide lateral illumination light that is laterally incident on the circuit board to be tested, and the initial illumination intensity is adjusted in the selected type of dimming area, and is adjusted to the present. Taking the image brightness value in the image to reach a second round of the first target interval value to obtain a set value of the second round side light illumination configuration; performing a second round of positive light adjustment step to maintain the second round side light Under the illumination of the set value of the illumination configuration, the forward illumination light that is positively incident on the circuit board to be tested is further provided, and the initial illumination intensity of the forward illumination light is adjusted in the selected type of dimming region, and the adjustment is performed. The image brightness value in the captured image reaches a second round of the second target interval value to obtain a set value of the second round of the first positive light illumination configuration, and the second round side light illumination Configuration and the first positive light of the second round Under the set value of the illumination configuration, the brightness value of the image data between the two types of dimming areas is obtained, and the corresponding brightness difference degree is obtained; and the second round of the second positive light adjustment step is performed, and the second round is maintained. Under the illumination of the set value of the first side light illumination configuration, the forward illumination light is further adjusted to provide a forward illumination light higher than a set value of the first positive light illumination configuration of the second round, the forward illumination light Further adjusting is performed in the selected type of dimming area, and adjusting to the image brightness value in the currently captured image reaches a second round of the third target interval value to obtain a second round of the second positive light irradiation group The set value of the state, and in the set configuration value of the side light illumination configuration and the second positive light illumination configuration of the second round, extract the brightness value of the image data between the two types of dimming regions, and obtain corresponding values The brightness difference is adjusted to select the illumination light adjustment configuration, wherein the maximum value of the second target first target interval value is greater than the maximum value of the first target interval value, and the second round second target interval value is equal to The second goal Intermediate value, the second wheel third target value based interval equal to the third target value range. The automatic dimming method according to Item 4, wherein the type of the dimming area is a metal type, a text type, a bright area type of a solder resist layer, and a dark area type of a solder resist layer, and The step of selecting the illumination light adjustment configuration is performed from the sidelight illumination configuration and the set value of the first positive illumination illumination configuration, the side illumination illumination configuration, and the set value of the second positive illumination illumination configuration. The second round side light illumination configuration and the set value of the second round of the first positive light illumination configuration, the second round side light illumination configuration, and the set value of the second round of the second positive illumination configuration One of the four is determined as the illumination light adjustment configuration, wherein the order of the determination rules is performed in the following order, and when the result of the difference degree is the same, the next rule is required to be determined, and the result of the degree of difference At different times, the configuration setting value with a large degree of difference is adjusted according to the illumination light; first, the degree of brightness difference between the bright area type of the solder resist layer and the dark area type of the solder resist layer; second, the metal type and The degree of brightness difference between text types; third, The difference between the bright spot type of the solder resist layer and the dark type of the solder resist layer and the brightness difference between the text types; and the fourth, the metal type and the bright area type of the solder resist layer and the dark type of the solder resist layer The degree of difference in brightness between the maximum values. The automatic dimming method according to any one of claims 1 to 5, wherein the selected type of the dimming area is of the metal type. The automatic dimming method of claim 6, wherein the image data corresponding to one of the at least one dimming region captured by the current illumination configuration is based on the selected type In the comparison of the pre-stored luminance threshold value data of the light region, the image data of the red light wavelength segment in the image data is compared. The automatic dimming method of claim 6, wherein in the dimming area setting step, the at least one dimming area and its corresponding type are set based on a user's delimitation. An optical detecting machine comprises an illumination source group, a camera group and a control group, wherein the control group controls the light intensity adjustment of the illumination source group and receives image data captured by the camera group, and the optical detection is performed on the optical detection When the machine performs automatic adjustment of the illumination source between different types of circuit boards to be tested, the control group operates to perform the automatic dimming method according to any one of the preceding claims 1 to 8.