JP2009094295A - Apparatus for measuring height of electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the height of an electronic component with high precision by accurately imaging regularly reflected light of line light when measuring the electronic component held by a suction nozzle etc., in three dimensions. <P>SOLUTION: In the apparatus which images a light cutting line by an imaging means 21 when the electronic component P held by a holding means 10 is irradiated with the line light L by a line light generating means 19 from obliquely below, and then measures the height of the electronic component based upon obtained image data, a mirror 27 which reflects the regularly reflected light of the line light irradiating the reverse surface on an imaging unit of the imaging means is fixed integrally to a light projection unit 26 which moves the line light generating means in parallel to the reverse surface of the electronic component to make a scan with the line light. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic component height measuring apparatus, and more particularly to an electronic component height measuring apparatus suitable for application to an electronic component mounting apparatus that automatically mounts on a printed circuit board or a substrate such as a liquid crystal display or a display substrate.

  For example, Patent Document 1 discloses an electronic component mounting apparatus that mounts electronic components such as so-called QFP and SOP on a substrate after three-dimensional measurement (height measurement).

  As shown in FIG. 1A, the three-dimensional measuring apparatus provided in the mounting apparatus illuminates the electronic component 130 held by the suction nozzle 117 by the LED illumination light source 131, and the electronic component 130 is illuminated. The two-dimensional data for positioning is acquired by imaging with a CCD camera 126 arranged below.

  Thereafter, after correcting the suction angle of the electronic component 130 from the two-dimensional data, the laser diode 121 is turned on, and the spot light that has passed through the collimator lens 122 and the focus lens 123 is reflected by the light projection mirror 124, thereby producing a line. The generator lens 125 projects line light 125 </ b> A onto the terminal portion 130 </ b> A of the electronic component 130 from an angle of 45 ° downward.

  Further, the light projection unit 127 is moved in the horizontal direction in the figure by the linear motor 128 to scan the electronic component 130 with line light. The projected image of the line light 125A is picked up by the CCD camera 126, the height data of each terminal is acquired from the light cutting line by the line light, and the flatness of the terminal portion 130A is inspected. If the flatness is appropriate, the electronic component 130 is mounted on the substrate based on the positioning data.

  In the three-dimensional measuring apparatus disclosed in Patent Document 1, height measurement (three-dimensional measurement) of an electronic component is performed by irradiating the electronic component with line light from obliquely below as shown in FIG. The terminal height data is acquired using a part of the irregularly reflected light (light reaching the camera).

  Further, as another method different from the measurement method shown in FIG. 1A, as shown in FIG. 1B, the projection position of the line light is fixed and the height of the terminal is increased using specular reflection light. There is a way to get data. In the case of this method, when the line light is scanned in the same manner as in FIG. 1A, the work distance (distance from the light projection position to the optical system) of the imaging camera changes depending on the measurement position of the electronic component. The depth of field (depth of focus) must be increased, and the size of the lens and the like must be increased. In order to measure more accurately while avoiding this, it is necessary to perform measurement by sub-scanning the measurement component in the direction perpendicular to the line light as shown by the double arrow in FIG. There is.

JP 2001-60800 A

  However, in the method of FIG. 1 (A), when the measurement location of the electronic component to be inspected (for example, the connector portion of the connector component) is a very flat surface (mirror surface state), the electronic component was irradiated. Line light is substantially specularly reflected, and light does not reach the CCD camera disposed below the electronic component, which makes it difficult or impossible to obtain terminal height data. In addition, in the configuration of the method using specular reflection light as shown in FIG. 1B, it is possible to measure a mirror-state electronic component. In this method, by operating the sub-scanning head. There is a problem in that a deviation in the height direction of the component occurs due to the influence of mechanical play and the like, and an error occurs with respect to the original height of the component.

  The present invention has been made to solve the above-mentioned conventional problems. When measuring the height of an electronic component held by a suction nozzle or the like, the measurement component is not changed without changing the imaging system such as the lens size. It is an object of the present invention to provide an electronic component height measuring device capable of measuring the height with high accuracy by accurately imaging the specularly reflected light of the line light without mechanically moving the lens. .

  According to the present invention, an optical cutting line when an electronic component held by a holding unit is irradiated with line light obliquely from below by the line light generating unit is imaged by the imaging unit, and based on the obtained image data, the electronic component is captured. In an electronic component height measuring apparatus for measuring the height of a component, a light projecting unit that scans line light by moving the line light generating means parallel to the lower surface of the electronic component is irradiated on the lower surface. The above-described problem is solved by integrally fixing a mirror that reflects the regular reflection light of the line light to the imaging unit of the imaging means.

  According to the present invention, a lens array that collects reflected light from the lower surface of the electronic component in a direction orthogonal to the line light is provided between the mirror and the imaging unit, or the held electronic component and the It may be arranged between the mirror.

  According to the present invention, the mirror that reflects the regular reflected light to the imaging unit of the imaging unit in the direction in which the line light irradiated on the lower surface of the electronic component is regularly reflected is integrated with the light projecting unit that scans the line light. Since it can be moved, the work distance of the regular reflection light when scanning the line light can always be kept constant. Therefore, the line light regularly reflected by the lower surface of the electronic component can always be accurately imaged, and the height measurement using the regular reflected light can be realized with high accuracy.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a perspective view showing an overview of the electronic component mounting apparatus used in the first embodiment according to the present invention.

  In this electronic component mounting apparatus, a transport path 2 is disposed in the center of the base 1 in the X direction. The transport path 2 also serves as a substrate holding unit, transports the substrate 3 in the X direction, and holds and positions the substrate 3 at a predetermined position on the transport path 2.

  In addition, electronic parts supply units 4 are arranged on both sides of the conveyance path 2, and a large number of parts feeders 5 are arranged in parallel in each supply unit 4. Each of the parts feeders 5 sequentially supplies the electronic components by feeding a tape that stores and holds the electronic components in the length direction.

  The X-axis table 6 is mounted with a transfer head 7 for electronic components, and the X-axis table 6 is connected to a Y-axis table 8A and a guide 8B arranged in parallel with the Y-axis table 8A. Is supported and installed. By driving the X-axis table 6 and the Y-axis tables 8A and 8B, the transfer head 7 is moved in the horizontal direction, and the parts feeder 5 is attached by a suction nozzle 10 shown in FIG. The electronic component is picked up from the component suction position and transferred onto the substrate 3.

  The transfer head 7 is moved by XY direction driving means comprising the X-axis table 6 and the Y-axis tables 8A and 8B. Below the movement path between the conveyance path 2 and the supply unit 4 is from a CCD camera or the like. A component recognition camera 9 is provided, and the transfer head 7 and the suction nozzle 10 are imaged from below by the camera 9.

  Then, the electronic component held by the transfer head 7 is imaged by the camera 9 so that the electronic component is identified and the displacement is detected. A three-dimensional measuring device (terminal portion height measuring device) 14 for inspecting the flatness of the terminal portion of the electronic component is disposed in the vicinity of the camera 9. The three-dimensional measuring device 14 will be described in detail later.

  A plurality of nozzle shafts 11 are respectively attached to the θ-axis motor 12 in the transfer head 7 as shown in an enlarged view in FIG. 3, and each nozzle shaft 11 can be independently rotated in the θ direction. The transfer head 7 is provided with a Z-axis motor 13 corresponding to each nozzle shaft 11 so that each nozzle shaft 11 can be moved up and down independently. A suction nozzle 10 is detachably mounted at the tip of each nozzle shaft 11, and a suction hole for sucking air and holding an electronic component is provided at the tip of the suction nozzle 10.

  As shown in FIG. 4A, the three-dimensional measuring device 14 is configured such that the laser light from the laser diode 15 is incident on the light projecting mirror 18 through the collimator lens 16 and the focus lens 17. Then, the reflected light is irradiated (projected) onto the electronic component P held by the suction nozzle 10 as line light by a line generator lens (line light generating means) 19. An imaging mirror 20 is disposed below the component P held by the suction nozzle 10, and an imaging camera 21 is disposed in the reflection direction of the imaging mirror 20. In the figure, reference numeral 15B denotes a laser controller, and 21B denotes a camera lens.

  The light projecting unit 26 in which the focus lens 17, the light projecting mirror 18, and the line generator lens 19 are integrally incorporated receives the specularly reflected light reflected from the terminal Pa of the electronic component P, and is vertically downward. And a lens array 27 for condensing the light reflected from the reflecting mirror 28 in a direction orthogonal to the line light. The light projecting unit 26 including these optical components is directly connected to the linear actuator 22 and is parallel to the lower surface of the electronic component P normally held in the horizontal direction (in the direction of the double arrow in the figure), and As shown in the top plan view of the main part of FIG. 5, it can be driven in a direction orthogonal to the irradiation line at the tip of the irradiated line light L.

  The lens array 27 has the lenses arranged in the line direction of the line light, and acts to collect the light spreading in the direction perpendicular to the line direction as shown in FIG. 4C.

  The lens array 27 is integrally formed of synthetic resin or glass so that a plurality of condensing lens portions 27A having the same focal length are arranged in a line as shown in an enlarged view in FIG. 4B. Each condensing lens portion 27A has a substantially rectangular outer shape so that a plurality of the condensing lens portions 27A are arranged within the length of the line light at the focal position of the line light, and one surface orthogonal to the line light is formed in a spherical shape. Spherical focusing type.

  As the lens array 27, a refractive index distribution type can be used instead of the spherical focusing type. In this case, the cylindrical lenses are formed in a row or a plurality of rows so that the cylindrical portions are in contact with each other, and the gaps between the columns are filled with an adhesive.

  The three-dimensional measuring device 14 applied to the present embodiment has a basic configuration except that the reflection direction of the laser beam by the light projecting mirror 18 differs by 90 ° and has a structure corresponding thereto. This is substantially the same as that shown in FIG. Therefore, the principle of three-dimensional measurement is substantially the same.

  Next, the three-dimensional measurement operation of the present embodiment having the above configuration will be described with reference to the flowchart shown in FIG.

  First, when the substrate 3 is loaded and positioned on the transport path 2 shown in FIG. 2 (steps 1 and 2), the transfer head 7 is mounted on the tip of the nozzle shaft 11 to pick up electronic components. The suction nozzle 10 that has been moved is moved onto the supply unit 4 (step 3).

  After the transfer head 7 is set to the component suction position, when the nozzle shaft 11 is lowered by driving the Z-axis motor 13, the suction nozzle 10 at the tip of the nozzle shaft 11 is lowered to the component suction height and is stored in the parts feeder 5. Immediately before coming into contact with the component, a vacuum generator (not shown) is actuated to create a negative pressure in the pipe line of the nozzle shaft 11, thereby sucking the electronic component in contact with the tip of the suction nozzle 10 (step 4). .

  Thereafter, in order to recognize the picked-up position and angle of the picked-up electronic component, it moves onto the component recognition camera 9 provided in the mounting apparatus body (step 5), and the position of the picked-up component is recognized (step 6). . Based on the result of the position recognition, the transfer head 7 moves onto the three-dimensional measuring device 14 disposed in the vicinity of the camera 9 (step 7), and the height measurement location of the sucked electronic component Are positioned so as to be the measurement position of the three-dimensional measuring device 14 (focal position of the line light).

  Next, the three-dimensional measurement by the three-dimensional measuring apparatus shown in FIG.

  The light emitted from the laser diode 15 which is a light source is condensed by the collimating lens 16 and becomes parallel light. The focus lens 17 narrows down the parallel light to become spot light. Spot light from the focus lens 17 is bent by the light projection mirror 18 so as to form an angle of 45 ° with the vertical axis.

  The line generator lens 19 placed immediately behind the bent optical path is a line light having a width (thickness) of 30 μm and a length of 40 mm (direction perpendicular to the paper surface of FIG. 4, dimension W of FIG. 5). As L, the light is projected to the terminal Pa of the electronic component P to be measured.

  The specularly reflected light from the terminal Pa of the electronic component P is first reflected vertically downward through the reflecting mirror 28 installed and fixed to the light projecting unit 26, and further enters the traveling direction of the reflected light. Light is preferably condensed through the arranged lens array 27. Thereafter, the image is captured by the imaging camera 23 via the prism mirror 21.

  Further, at this time, the light projecting unit 26 connected to the linear actuator 22 is driven by the linear actuator 22 in the direction of the left and right arrows shown in the figure (with respect to the irradiation line of the line light that is parallel and irradiated to the lower surface of the electronic component Perform a linear motion back and forth in the orthogonal direction.

  As a result, the light projecting unit 26 performs forward / backward linear movement toward the parallel light beam formed by the collimator lens 16. Since the image forming action of the lens 17 is not affected, when the electronic component P to be measured is normally held in the horizontal direction, the line light of a certain width is always irradiated to the terminal. Become.

  Therefore, in FIG. 4A, the light projecting unit 26 is moved from right to left at a constant speed (for example, 700 mm / sec). When the light reaches a position where specularly reflected light can enter a predetermined location in the field of view of the imaging camera 21, the laser diode 15 is turned on for a predetermined time (for example, 50 μsec). Then, even when the surface of the terminal Pa of the electronic component P at the light projection position is rough, the reflected light is sufficiently condensed by the lens array 27, so that an image with good contrast can be captured by the imaging camera 21. High-precision height measurement can be performed.

  By performing image processing on the captured image data, it is possible to perform three-dimensional measurement (terminal height measurement) of the electronic component. The principle of this three-dimensional measurement will be briefly described below.

  FIG. 7 is a diagram showing a state in which the example of the electronic component is QFP and the lead terminal is three-dimensionally measured.

  FIG. 7A shows that the electronic component P is parallel to each of the XY axes on the top of the three-dimensional measuring device 14 by driving the respective axes of XYθ, and the field of view of the three-dimensional measuring device 14 is shown. It is a top view which shows the state positioned so that it might correspond to a center position, and has shown the image of the state in which the line light L scanned by the linear actuator 22 is irradiated to the lead terminal Pa of the electronic component P. FIG.

  FIG. 7B is a side view showing a state where a part of the light diffusely reflected by the lead terminal Pa is reflected in the vertical direction (light captured by the imaging camera). C) is an enlarged view of the lead terminal Pa irradiated with the line light L in FIG.

  Here, among the lead terminals Pa to be measured, there is a lead terminal Pb having a different height compared to others due to deformation or the like, and the height at which the line light L is irradiated by this is shown in FIG. As shown, suppose that it differs from the normal terminal Pa by Δt. When the line light L is irradiated, the lead terminal Pa is picked up as an optical section line image as shown in FIG. 8 by an imaging camera provided below the lead terminal Pa, but the lead terminal Pb having a different height is Δx as shown in FIG. Images are taken at positions separated by ′.

  When the surfaces of the lead terminals Pa and Pb are close to a mirror surface, the projection angle of the line light L is 45 ° with respect to the lead terminal Pb, so that the optical axis connecting the lead terminal and the imaging camera 21. Is inclined by 45 ° with respect to the straight direction, and therefore three-dimensional (height) measurement is possible as Δx ′ = √2 × Δt.

  As a result of the three-dimensional measurement in Step 8, when a terminal having a different height is detected in the measurement component and the measured value Δx ′ is larger than a threshold that can be arbitrarily set, the measured electronic component is abnormal (NG) ), And an appropriate error process is performed (step 9), such as moving to a return tray (not shown) in the apparatus and returning the suction component by air blow.

  As a result of the three-dimensional measurement in step 8 described in detail above, in the case where the abnormality of the electronic component is not recognized, the transfer head 7 is placed at a predetermined position on the substrate 3 fixed to the transport path 2. The electronic component is mounted on the substrate 3 by driving the θ-axis motor 12 and the Z-axis motor 13 (step 11).

  Thereafter, the production operation is continued until all the electronic components are mounted on the substrate 3 (step 12).

  According to the embodiment described above in detail, the following effects can be obtained.

  (1) A terminal of an electronic component using regular reflection light when scanning the line light, even for an electronic component having a measurement part close to a mirror surface, which was difficult with the conventional method described with reference to FIG. It is possible to measure the height of the part with high accuracy.

  (2) The line light is reliably scanned on the lower surface of the electronic component without mechanically sub-scanning the measurement component, and the measurement using the specularly reflected light at that time can be accurately performed at high speed.

  (3) Since the reflected light of the line light is once condensed by the lens array before image formation, an image with better contrast can be obtained even with a terminal of an electronic component having a rough surface. Therefore, it is possible to measure the height of the terminal portion with high accuracy regardless of the types of components having different surface states of the terminals.

  FIG. 9 is a cross-sectional view corresponding to FIG. 4A, showing the main part of the three-dimensional measuring apparatus according to the second embodiment of the present invention.

  In the present embodiment, the lens array 27 is disposed between the reflection position of the terminal Pa of the electronic component P to which the line light L is projected and the mirror 28. Thereby, substantially the same effect as in the case of the first embodiment can be obtained.

Side view showing the outline of the three-dimensional measuring device Side view showing the outline of another three-dimensional measuring device The perspective view which shows the general view of the electronic component mounting apparatus applied to 1st Embodiment which concerns on this invention The perspective view which shows the transfer head mounted in the said electronic component mounting apparatus 1 is a schematic side view showing a three-dimensional measuring apparatus according to a first embodiment of the present invention. The perspective view which expands and shows the lens array applied to this embodiment The image figure which shows the characteristic of the optical action of the above-mentioned lens array Explanatory drawing which shows the state which looked at the principal part of the said three-dimensional measuring apparatus from the upper surface Flow chart showing the operation of this embodiment Explanatory diagram showing the principle of three-dimensional measurement Other explanatory diagram showing the principle of three-dimensional measurement The schematic side view which shows the three-dimensional measuring apparatus of 2nd Embodiment which concerns on this invention.

Explanation of symbols

10 ... Suction nozzle (holding means)
DESCRIPTION OF SYMBOLS 14 ... Three-dimensional measuring apparatus 15 ... Laser diode 16 ... Collimating lens 17 ... Focus lens 18 ... Projection mirror 20 ... Imaging mirror 21 ... Imaging camera 22 ... Linear actuator 26 ... Projection unit 27 ... Lens array 28 ... Mirror P ... Electron Parts Pa ... Terminal L ... Line light

Claims (2)

The electronic component held by the holding unit is imaged by the imaging unit when the line light is irradiated from the obliquely lower side by the line light generating unit, and the height of the electronic component is obtained based on the obtained image data. In the height measuring device of electronic parts that measure
The line light generating means is moved in parallel with the lower surface of the electronic component, and the regular reflection light of the line light irradiated on the lower surface is reflected to the image pickup unit of the image pickup means. A height measuring device for electronic parts, wherein the mirror to be fixed is integrally fixed.   A lens array that collects reflected light from the lower surface of the electronic component in a direction orthogonal to the line light is disposed between the mirror and the imaging unit, or between the electronic component and the mirror. The height measuring device for an electronic component according to claim 1, wherein:

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