JPH06185994A - Inspecting device for mounted substrate - Google Patents

Abstract

PURPOSE:To provide a mounted substrate inspecting device which can accurately discriminate the propriety of the mounting state of a mounted substrate even when the substrate is deviated in position. CONSTITUTION:The light reflected by the mounting surface of a mounted substrate when the mounting surface is scanned with laser light is led to a first and second photodetectors 9 and 10 and a data processing section 11 finds data about the height distribution on the mounting surface from the output signal of the first photodetector 9 and stores the data in a memory 12. Another data processing section 13 finds data about the luminance distribution on the mounting surface from the output signal of the second photodetector 10 and a correcting amount calculating section 15 calculates the deviation of the mounted substrate in the direction from the position of a mark contained in the data. An inspecting area correcting section 17 corrects the position of an inspecting area read out from an inspecting area memory 16 by a correcting amount and a discriminating section 20 compares the height distribution corresponding to the inspecting area with reference data. Thus the propriety of the mounting state of the mounted substrate is discriminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting board inspecting apparatus for inspecting a mounting state of a component mounted on a printed circuit board by using reflected light when scanning a laser beam.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open No. 4-86548 has been known as a disclosure of this type of inspection apparatus.

This inspection apparatus has a table for moving a mounting substrate in a predetermined direction, a laser, a rotating mirror for scanning a mounting surface of the mounting substrate with laser light in a direction orthogonal to the substrate moving direction, and a reflection from the mounting surface. A photodetector that receives light and converts it into an electrical signal, a data processing unit that calculates height distribution data of the mounting surface based on the output signal of the photodetector, and a height distribution data memory that stores the height distribution data. And an inspection range memory that stores position data related to the inspection range set corresponding to the mounted component, and a movement inspection region memory that stores data related to the movement inspection region set to be movable within the inspection range, Judgment processing for reading the height distribution data corresponding to the inspection area from the height distribution data memory at each moving position, adding the values, and comparing the position where the value is maximum with a threshold value to judge pass / fail And means.

The inspection of the mounting state in the above inspection apparatus is performed by scanning the mounting surface of the mounting substrate with laser light in a direction orthogonal to the substrate moving direction. The reflected light from the mounting surface is guided to the photodetector and converted into an electrical signal,
After being A / D converted by the data processing means, it is converted into data relating to the height distribution of the mounting surface and stored in the memory. On the other hand, the predetermined inspection range and the inspection area are read from the inspection range memory and the movement inspection area memory, respectively, and the height distribution data corresponding to each movement position of the inspection area is read from the memory and added by the determination processing means. , The position where the value is maximum is compared with the threshold value to judge the quality of the mounting state.

[0005]

By the way, in the above-mentioned conventional inspection apparatus, when the mounting position of the mounting board with respect to the table is deviated, the influence of the deviation appears in the inspection area and the height distribution data of the area is deviated. Occurs, and even if the component is mounted at a normal position, it is difficult to determine that the component is defective. Although it is possible to mechanically correct the substrate position in advance, it is extremely difficult to completely eliminate minute deviations.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mounting board inspecting apparatus capable of accurately determining whether the mounting state is good or not even when the mounting board is misaligned. is there.

[0007]

In order to achieve the above object, according to the present invention, a moving means for moving a mounting substrate in a predetermined direction, a laser, and a laser on a mounting surface of the mounting substrate in a direction orthogonal to the substrate moving direction. Laser light scanning means for scanning light, photodetector for receiving reflected light from the mounting surface and converting it into an electric signal, and data processing for calculating height distribution data of the mounting surface based on the output signal of the photodetector Means, an inspection area memory for storing an inspection area set corresponding to the mounted component, and a judgment means for comparing the height distribution data corresponding to the inspection area with reference data to judge whether the mounting state is good or bad. In the mounting board inspection device described above, a plurality of marks are provided on the mounting board, the second photodetector receives reflected light from the mounting surface, and the brightness of the mounting surface is determined based on the output signal of the second photodetector. Distribution data Second data processing means for calculating, correction amount calculation means for calculating the deviation of the mounting substrate in the θ direction from the mark position in the brightness distribution data, and inspection area correction means for correcting the position of the inspection area based on the correction amount. And are provided.

[0008]

In the mounting board inspection apparatus according to the present invention, the light reflected from the mounting surface during laser beam scanning is guided to two photodetectors, respectively. The reflected light guided by one photodetector is converted into an electric signal, converted into data relating to the height distribution of the mounting surface by the data processing means, and stored in the memory. Also,
The reflected light guided to the other photodetector is converted into an electric signal, converted into data relating to the luminance distribution of the mounting surface in the data processing means, and mounted in the correction amount computing means from the mark position in the luminance distribution data. The deviation of the substrate in the θ direction is calculated.

The above height distribution data is read from the memory according to the inspection area and compared with the reference data by the judging means. At this time, the position of the inspection area is corrected in the θ direction by the above-mentioned deviation. To be done.

[0010]

1 to 6 show one embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a mounting board inspection apparatus, FIG. 2 is a top view of a mounting board, and FIG. 3 is a block of an electric circuit. 4 and 5 are flowcharts of inspection control, FIG. 5 is a flowchart of correction amount calculation processing, and FIG. 6 is an explanatory diagram of correction amount calculation.

First, the apparatus configuration will be described with reference to FIG. In the figure, 1 is a printed circuit board (mounting board) on which various electronic components are mounted, and 2 is a table for moving the mounting board 1 in a predetermined direction. As shown in FIG. 2, marks 1a for position detection are provided at two corners of the mounting board 1. The mark 1a is formed by printing a circular copper pattern on a substrate made of a glass epoxy material.

3 is a laser using a semiconductor such as He-Ne as a light source, 4 is a polygonal prism rotation mirror, 5 is a lens, 6 is a reflection mirror, 7 is a condenser lens, 8 is a half mirror, and 9 is PSD ( A first photodetector 10 incorporating a semiconductor position detecting element is a second photodetector incorporating a photodiode. The light of the laser 3 is rotated by the rotating mirror 4 and is applied to the mounting surface of the mounting substrate 1 through the lens 5 in a direction orthogonal to the substrate moving direction, and the reflected light from the mounting surface is reflected by the reflecting mirror 6, the lens 5, and the rotating mirror. 4, the first lens 9 and the second lens 10 through the condenser lens 7 and the half mirror 8.
Are led to each.

Next, the circuit configuration will be described with reference to FIG. In the figure, a data processing unit 11 A / D-converts the output signal of the first photodetector 9 and converts it into data relating to the height distribution of the entire mounting surface. A height distribution data memory 12 stores this data.

Reference numeral 13 is a data processing section, which is the second photodetector 10.
The output signal of is subjected to A / D conversion and converted into data relating to the luminance distribution of the entire mounting surface. Reference numeral 14 is a brightness data memory for storing this data. Reference numeral 15 denotes a correction amount calculation unit that calculates the shift of the mounting substrate 1 around the table vertical axis (θ direction) from the mark position in the brightness distribution data.

Reference numeral 16 denotes an inspection area memory, which stores position data relating to a plurality of inspection areas set corresponding to mounted components. This inspection area is set by using CAD data when designing the mounting board. An inspection area correction unit 17 corrects the position of the read inspection area based on the correction amount and reads out height distribution data corresponding to the corrected inspection area from the memory 12.

A reference data memory 18 stores data relating to the height distribution of the entire mounting surface when the components are correctly mounted on the mounting surface. Reference numeral 19 denotes a threshold value memory, which stores a threshold value serving as a reference for determining whether the mounting state is good or bad. The above-mentioned reference data and threshold value are keyed in advance according to the mounting board, but height distribution data of non-defective products may be used as the reference data.

Reference numeral 20 denotes a determination unit, which calculates an erroneous calculation between the height distribution data corresponding to the corrected inspection area and the reference data, and compares the error with a threshold value to determine whether the mounting state is good or bad.
Reference numeral 21 is a CRT that displays the determination result.

The data processing units 11 and 13, the correction amount calculation unit 15, the inspection area correction unit 16 and the determination unit 18 are composed of a well-known CPU, and perform predetermined processing according to a control program stored in the ROM which will be described later. .

Here, the operation and processing procedure of the inspection apparatus will be described with reference to FIGS. Table 2
Mounting substrate 1 fed below lens 5 with the movement of
Is scanned by laser light over the entire mounting surface in a direction orthogonal to the substrate moving direction (S1 in FIG. 4). The light reflected from the mounting surface during this scanning is reflected by the reflecting mirror 6, lens 5,
The light is guided to the first photodetector 9 and the second photodetector 10 through the rotating mirror 4, the condenser lens 7 and the half mirror 8, respectively.

The reflected light guided to the second photodetector 10 is converted into an electric signal here and then used for the calculation processing of the correction amount (S2 in FIG. 4). As shown in ST1 to ST5 of FIG. 5, the output signal of the second photodetector 10 is A / D converted by the data processing unit 13 and further binarized to obtain the luminance distribution of the entire mounting surface. After being converted into such data, it is stored in the luminance distribution data memory 14. Since the mark 1a made of a copper pattern has a higher reflectance than the substrate itself, the mark 11a appears prominently in the luminance distribution data.
Subsequently, the correction amount calculation unit 15 detects the mark position in the brightness distribution data, calculates the deviation of the mounting substrate in the θ direction from both mark positions, and stores the correction amount θ1 in the RAM or the like.

More specifically, as shown in FIG. 6, when the substrate moving direction is X and the scanning direction is Y, the distance between marks on the straight line S connecting both marks 1a and the deviation Δx of the mark 1a in the X direction, Alternatively, the inclination θ1 of the straight line S with respect to the substrate moving direction is calculated from the Y-direction deviation Δy by a trigonometric function. still,
The correction amount θ1 is calculated by the deviation Δx of the mark 1a in the X direction and Y
It is also possible to calculate the inclination θ1 of the straight line S from the direction deviation Δy by a trigonometric function.

On the other hand, the reflected light guided to the first photodetector 9 is converted into an electric signal here, and then the output signal is A / D converted by the data processing unit 11 and further mounted by an appropriate calculation formula. After being converted into data relating to the height distribution of the entire surface, it is stored in the height distribution data memory 12 (S in FIG. 4).
3 to S5).

Next, from the inspection area memory 16, the position data relating to the inspection area and the above-mentioned correction amount .theta.
7, the position data of the inspection area is position-corrected by the correction amount θ1 (S6 to S8 in FIG. 4). Then, the height distribution data corresponding to the inspection area after the position correction is stored in the memory 1
2 is read (S9 in FIG. 4).

Next, the reference data corresponding to the position-corrected inspection area is read from the reference data memory 18, and an error between the reference data and the height distribution data, for example, a square error is calculated (FIG. 4 S10, S11). And
The threshold value is read from the threshold value memory 19, the quality of the mounting state is determined by comparison with the above error, and the determination result is displayed on the CRT 21 (S13 to S1 in FIG. 4).
5).

As described above, according to the mounting board inspection apparatus described above, the reflected light at the time of scanning the laser light is detected by the first and second photodetectors 9,
10 to obtain data relating to the height distribution of the mounting surface from the output signal of the first photodetector 9 and the second photodetector 1
Since the data relating to the luminance distribution of the mounting surface is obtained from the output signal of 0, the position of the inspection area can be corrected by calculating the deviation of the mounting substrate in the θ direction from the mark position in the data.
Even if the mounting substrate 1 on the table has a positional deviation, the inspection area can be automatically corrected according to the positional deviation, and the quality of the mounting state can be accurately determined. In addition, it is possible to save the labor of correcting the position and orientation of the mounting substrate before the laser beam scanning, which contributes to the reduction of the inspection time, and the degree of freedom of the table can be reduced accordingly to simplify the structure.

In the above embodiment, the first photodetector has a PS.
Although D is the photodiode used for the second photodetector, the photodetector element used for the photodetector may be other than these, and the same element may be used for both photodetectors. Good. Further, the laser beam scanning means including a rotating mirror and a lens, and the reflecting means including a reflecting mirror, a lens and a rotating mirror may be replaced by a well-known structure other than the illustrated example.

[0027]

As described in detail above, according to the present invention,
The reflected light at the time of scanning the laser light is guided to two photodetectors,
The data related to the height distribution of the mounting surface is obtained from the output signal of one photodetector, and the data related to the luminance distribution of the mounting surface is obtained from the output signal of the other photodetector, and the mounting board is determined from the mark position in the data. Since it is possible to correct the position of the inspection area by calculating the deviation in the θ direction of, the inspection area is automatically corrected according to the deviation even if the mounting board on the table has a positional deviation, It is possible to accurately determine the quality. In addition, it is possible to save the labor of correcting the position and orientation of the mounting substrate before the laser beam scanning, which contributes to the reduction of the inspection time, and the degree of freedom of the table can be reduced accordingly to simplify the structure.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a mounting board inspection apparatus.

FIG. 2 is a top view of a mounting board.

FIG. 3 is a block diagram of an electric circuit.

FIG. 4 is a flowchart of inspection control

FIG. 5 is a flowchart of correction amount calculation processing.

FIG. 6 is an explanatory diagram of correction amount calculation.

[Explanation of symbols]

1 ... Mounting board, 1a ... Mark, 2 ... Table, 3 ... Laser, 4 ... Rotating mirror, 5 ... Lens, 9 ... First photodetector,
10 ... 2nd photodetector, 11 ... Data processing part, 12 ... Height distribution data memory, 13 ... Data processing part, 15 ... Correction amount calculation part, 16 ... Inspection area memory, 17 ... Inspection area correction part, 20 ... Judgment section.

Claims (1)

[Claims] 1. A moving means for moving a mounting board in a predetermined direction, a laser, a laser beam scanning means for scanning a mounting surface of the mounting board with laser light in a direction orthogonal to the board moving direction, and a reflection from the mounting surface. A photodetector that receives light and converts it to an electrical signal, a data processing unit that calculates height distribution data of the mounting surface based on the output signal of the photodetector, and an inspection area set corresponding to the mounting component A mounting board inspection apparatus having a storage area memory for storing and a judgment means for comparing the height distribution data corresponding to the inspection area with reference data to judge whether the mounting state is good or bad. At the same time, a second photodetector that receives the reflected light from the mounting surface, a second data processing unit that calculates the luminance distribution data of the mounting surface based on the output signal of the second photodetector, and the luminance distribution In the data A correction amount calculating means for calculating a θ direction deviation of the mounting substrate from the mark position, is provided an inspection area correcting means for correcting the position of the inspection area based on the correction amount, the mounting board inspection apparatus characterized by.