JP3419118B2 - Appearance inspection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention processes a color image of a plurality of colors in the field of FA, and evaluates the quality of electronic parts, cream solder, TAB tape, etc. on a printed circuit board. The present invention relates to a visual inspection device for determining the condition. 2. Description of the Related Art Generally, TAB tapes and mounting substrates are almost always produced by automatic machines. As described above, when an automatic machine is used, due to various factors, defective products such as lead etching defects and stains and scratches on the surface in the case of TAB tape and printing defects and mounting defects in the case of a mounting substrate may occur. The inspection process is indispensable in manufacturing. However, if such an inspection relies on a visual inspection by an inspection worker, the occurrence of an inspection error cannot be completely eliminated. Visual inspection has reached its limit with the adoption of TAB tapes. For this reason, automatic inspection machines for TAB tapes and mounting boards have become important. Various companies have made various proposals, such as monochrome cameras, color cameras, three-dimensional cameras, and X-ray cameras. . In consideration of various performances such as accuracy, tact, and cost, tact is particularly important in an in-line inspection machine, and inspection with a color camera that has a short imaging time and a large amount of information has attracted attention. Hereinafter, a conventional apparatus for inspecting a mounting board using a color image will be described with reference to the drawings. FIG. 4 shows a conventional apparatus for inspecting a component mounting board based on a color image disclosed in Japanese Patent Application Laid-Open No. 62-180250. In FIG. 4, reference numeral 1 denotes a printed circuit board to be inspected, 2 an XY table on which the printed circuit board is mounted, 3 an illumination for illuminating the printed circuit board, 4 an imaging unit for a color image, and 5 a signal for the imaging unit. Processing unit, 6, 7,
Reference numerals 8, 9, and 10 denote an image input unit, an image processing unit, a determination unit, a memory, a control unit, 11 an image controller, 12 a table controller, and 13 a determination result output unit. [0007] With respect to an inspection apparatus for a component mounting board composed of such components, the relationship between these components and the operation thereof will be described below. First, the printed circuit board 1 to be inspected on the XY table 2 is illuminated by the illumination 3, and an image is captured by the color image capturing unit 4. Then, the image processing is performed by the processing unit 5 that processes the signal of the imaging unit 4,
The determination result is output to the determination result output unit 12. At this time, in the processing unit 5, the output image signal of the imaging unit 4 is sent to the memory 9 through the image input unit 6 and stored. The image signal stored in the memory 9 in this way is judged by the image processing unit 7, the judgment unit 8, and the control unit 10 as pass / fail, and is output to the judgment result output unit 13. At this time, components such as a board, an electronic component, and a cream solder are distinguished by a difference in color information of each pixel. On the other hand, when an image is captured by a black-and-white camera, the number of parts that cannot be identified increases because identification is performed only by luminance information. In this manner, the conventional example of FIG. 4 realizes a component mounting board inspection apparatus using a color image. However, in the above-described conventional configuration, a lead portion on a TAB tape, a resist portion, a resin sealing portion, a component on a mounting board, or the like is identified by a difference in color information of each pixel. Has the following problems. FIG.
FIG. 3 is a diagram plotting chromaticity and luminance of each pixel when an image of a substrate is taken. As can be seen here, the chromaticity information of most parts that must be distinguished is the maximum value of 10
%, And the luminance information of the lead portion is very high. At this time, if the light amount of the illumination unit is increased to increase the resolution of the chromaticity, the luminance of the lead unit is saturated, and the color extraction accuracy of the lead unit is reduced. Conversely, in order to increase the color extraction accuracy of the lead portion, it is necessary to reduce the light amount of the illumination portion, and the resist portion and the resin sealing portion cannot be distinguished. FIG. 3 is a diagram showing an example in which the light amount is increased, and the lead portion is in a state close to white (R, G maximum). In general, the CCD sensor of a color CCD camera has a weaker light sensitivity to blue light than other colors, so that other colors (R,
When the gain is increased to the same signal level as in the case of G), in the case of an object having a low signal level, there is a tendency that the amount of noise is relatively increased. [0010] For this reason, in the case of the conventional image pickup means under a normal light amount, there is a problem that it is difficult to obtain a sufficient color resolution of both high and low signal levels. The characteristics of the human eye are logarithmic characteristics,
The high resolution of the hue difference between dark colors is also a phenomenon consistent with this. In order to solve the above-mentioned problems, the present invention distinguishes a difference in color and a difference in luminance of a lead portion, a resist portion, a resin sealing portion, and the like with a sufficient resolution, and can stably perform a quality inspection. An apparatus is provided. [0013] In order to solve the above-mentioned problems, an appearance inspection apparatus according to the present invention is provided with an imaging means for imaging a color image of an inspection object having a chromaticity difference and a luminance difference. When,
3 of the color of the inspection object imaged by the imaging means
Color coordinate conversion means for converting the primary colors into luminance and chromaticity information;
A color coordinate data holding unit that holds a plurality of types of calculation coefficients used for calculating color coordinates in the color coordinate conversion unit; an inspection data holding unit that holds inspection data having information on the inspection object; and Decoding means for reading the color coordinate data from the color coordinate data holding means based on the data specifying the color coordinates, and the luminance and chromaticity information converted by the color coordinate conversion means for each imaging screen.
Binary threshold value stored in the inspection data holding means
A color extraction unit that performs a binary process in accordance with
Means for performing binary image processing on the basis of the image information subjected to the binary processing to determine acceptability, wherein the color coordinate data holding means comprises a color coordinate system for inspecting a high-luminance inspection object. A calculation coefficient for calculating luminance only from the blue color whose light intensity sensitivity in the image pickup unit is the least among the primary colors, and luminance and chromaticity from other than the blue color whose light intensity sensitivity is low in order to inspect an inspection object having a low luminance. An arithmetic coefficient to be operated is held, and the control means switches the arithmetic coefficient according to the luminance of the inspection object. In addition, the visual inspection apparatus of the present invention uses, as an operation coefficient held in the color coordinate conversion means, a blue light quantity sensitivity of the image pickup means which is the lightest among the three primary colors in order to inspect an object having a high luminance. The calculation coefficient that calculates the luminance only from, and the calculation coefficient that calculates the luminance and chromaticity from other than blue, where the light intensity sensitivity is low to inspect the low-luminance inspection object, are held. And control means for immediately switching the operation coefficient according to each inspection object. The visual inspection apparatus of the present invention uses a color coordinate conversion system for calculating luminance only from blue for a lead having a large signal level at the time of inspection, and uses a resist and resin sealing portion having a small signal level. By using a color coordinate conversion system that calculates luminance and chromaticity from color signals other than blue, conventional methods using a constant amount of incident light can accurately control both the lead and the resist or resin encapsulation. What was difficult to identify well can now be identified reliably,
The quality of the inspection object can be inspected. At this time, since the color coordinate conversion system is changed according to the inspection object, a sufficient resolution can be obtained for each color video signal output of the lead portion, the resist portion, the resin sealing portion, and the like. As described above, by providing the means for switching the color coordinate conversion system according to the object to be inspected, the resist section and the resin sealing section which require a high resolution with a small signal and the signal is large and the luminance is saturated. It is possible to stably identify the lead portion that is easy to perform, and accurately inspect the quality of the lead, resist, and resin sealing. An embodiment of the appearance inspection apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a visual inspection apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 14 denotes a color image processing unit for performing color coordinate conversion and color extraction, 15 denotes a color coordinate conversion unit, 16 denotes color extraction means, 17
Is color coordinate data holding means, 18 is inspection data holding means,
Reference numeral 19 denotes a TAB tape to be inspected. The following describes the relationship between these components and the operation of the mounting board inspection apparatus including such components. In the first embodiment, the reflected light from the TAB tape 19 to be inspected is imaged by the color CCD camera 4 for imaging. At this time, the illumination 3 or the aperture of the color CCD camera 4 is adjusted to a level at which a signal of an object having a small signal level such as a resist or resin sealing can be sufficiently recognized. The captured image is passed to a color image processing unit 14 and is converted into luminance and chromaticity information by a color coordinate conversion unit 15. At this time, the control unit 10 controls the inspection data holding unit 1
8 is read, and the color coordinate data is read from the color coordinate data holding unit 17 based on the data specifying the color coordinates described in the test data. The color coordinate data which is difficult to read is passed to the color coordinate conversion unit 15 and performs color coordinate conversion according to the inspection object. The image information converted by the color coordinate conversion unit 15 is output to a color extraction unit 16.
Binary processing is performed according to the binarization threshold value stored in the inspection data holding unit 18 for each imaging screen. Next, the determination unit 8 performs binary image processing to determine the quality. According to the second embodiment of the present invention, as the data held in the color coordinate data holding unit 17, color coordinate conversion using only blue light with low light intensity sensitivity is realized for a lead unit having a large signal level. Using the operation data shown in the following equation (Equation 1), for the other resist portions and resin sealing portions having a small signal level, when the signal level is low, blue which is easily affected by noise is excluded. The calculation data shown in the equation (Equation 2) for realizing the color coordinate conversion is used. ## EQU1 ## ## EQU2 ## In this way, by successively switching the color coordinate conversion system according to the object to be inspected during the inspection, it is possible to stably identify both the lead portion having a high signal level and the resist portion or resin sealing portion having a low signal level. It is possible to configure an appearance inspection apparatus that performs the inspection accurately and stably inspects the quality of the lead, resist, and resin sealing. As described above, according to the present invention, in an inspection apparatus for inspecting the quality of an electronic component mounting board or a TAB tape by using a plurality of color image pickup means, depending on an inspection object. By providing a means for switching the coordinate data of the color coordinate conversion system, in a configuration using ordinary imaging means as in the conventional example, both the resist portion and the resin sealing portion having a low signal level and the lead portion having a high signal level are provided. Can overcome the conflicting problem of discrimination of colors, distinguish the color difference of the resist part, resin sealing part, lead part, etc. with sufficient resolution, and stably inspect the quality of electronic component mounting boards and TAB tapes become.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a visual inspection device according to first and second embodiments of the present invention. FIG. 2 is a diagram showing color distribution of leads, resist, and a resin sealing portion on a TAB tape. FIG. 3 shows a lead on a TAB tape when the light amount is increased,
FIG. 4 is a diagram showing a color distribution of a resist and a resin sealing portion. FIG. 4 is a block diagram of a conventional mounting board inspection apparatus. [Description of References] 1 printed board 2 XY table 3 illumination 4 color CCD camera 8 recognition determining section Reference Signs List 10 control unit 14 color image processing unit 15 color coordinate conversion unit 16 color extraction unit 17 color coordinate data holding unit 18 inspection data holding unit 19 TAB tape

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-45799 (JP, A) JP-A-6-147846 (JP, A) JP-A-6-243235 (JP, A) 67209 (JP, A) JP-A-6-109653 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/88 G01B 11/24 H05K 3/34 512 H05K 13/08

Claims (1)

(57) [Claim 1] An image pickup means for picking up a color image of an inspection object having a chromaticity difference and a luminance difference, and an image of the inspection object picked up by the image pickup means. Color coordinate conversion means for converting the three primary colors into information on luminance and chromaticity; color coordinate data holding means for holding a plurality of types of operation coefficients used for calculating color coordinates in the color coordinate conversion means; Inspection data holding means for holding inspection data having object information; control means for decoding the inspection data and reading color coordinate data from the color coordinate data holding means based on data designating color coordinates; The luminance and chromaticity information converted by the conversion means is stored in the inspection data for each imaging screen.
A color extraction unit that performs a binary process according to a binary threshold value stored in a data holding unit, and performs a binary image process based on the image information that has been subjected to the binary process by the color extraction unit. The color coordinate data holding means,
In order to inspect an inspection object having a high luminance, an operation coefficient for calculating luminance only from blue, which is the lightest amount of light in the imaging unit, is used for inspecting an inspection object having a low luminance. And a calculation coefficient for calculating luminance and chromaticity from a color other than the blue light intensity sensitivity, wherein the control means switches the calculation coefficient according to the luminance of the inspection object. appearance inspection apparatus that inspection object.