JP3468669B2 - Imaging device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device,
In particular, the present invention relates to an image pickup device used for confirming the position, loss, etc. of an electronic component in an electronic component mounting device.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field, there is JP-A-8-205004. The image pickup device described in this publication is installed during the transportation of an electronic component sucked by a suction nozzle onto a printed circuit board.
The positional deviation that occurs when the electronic component is sucked by the suction nozzle is inspected by image processing. Specifically, the bottom surface and leads of electronic components are illuminated by LEDs, and the reflected light is CCD.
The state of the bottom surface of the electronic component and the state of the leads are inspected by performing image processing based on the signal output from the CCD and output from the CCD.

[0003]

However, since the conventional image pickup apparatus is configured as described above, there are the following problems. In recent years, in order to reduce the cost of electronic components, the electronic components may not be subjected to honing processing for deburring. The surface of the electronic component in such a state is close to a mirror surface state. Therefore, when such an electronic component is imaged by the conventional imaging device, the bottom surface of the electronic component is illuminated from diagonally below with a small elevation angle of nearly 45 degrees. As a result, the light reflected by the bottom surface and the leads is difficult to enter into the observation window located right below, and the light amount is insufficient when the image is captured by the CCD.
In particular, small electronic parts, such as capacitors having a size of 10 mm square or less, are prominently erroneously recognized, and sometimes cannot be recognized. Further, it is possible to increase the distance between the electronic component and the illumination in order to image the electronic component as described above without any inconvenience, but there is a problem that the device itself becomes large.

The present invention has been made in order to solve the above-mentioned problems, and in particular, an object thereof is to enable downsizing of the apparatus itself and to improve the recognition accuracy of an object to be read.

[0005]

According to a first aspect of the present invention, there is provided an image pickup device having two LED light sources for illuminating an object to be read arranged in a reading area with illumination light.
An illumination system, an imaging system for imaging the read object by receiving reflected light from reading object occurring when illuminated by the illumination system, an arrangement has been reflected light between the imaging system and the illumination system In an imaging device having a lens system for forming an image on the imaging system, a total reflection mirror that bends the optical path by approximately 90 degrees is arranged on the optical path between the object to be read and the lens system. It is placed between the reflection mirror and the lens system, emits light toward the total reflection mirror, and when the indirect light reflected by the total reflection mirror is incident on the bottom surface of the object to be read, it is larger than the bottom surface. and small field illumination forming the elevation, reading object and Zenhan
Place it between the shooting mirror and the bottom of the object to be read.
Light is emitted, and the emitted direct light is the bottom of the read object.
Large field illumination that makes a small elevation angle to the bottom surface when entering the surface
It is characterized by having a light .

In this image pickup device, the reading object arranged in the reading area is illuminated by the light emitted from the LED . Therefore, when imaging a small object to be read such as a condenser, the bottom surface of the object to be read is illuminated by small-field illumination. Since this small-field illumination is indirect light that is once reflected by the total reflection mirror, it is possible to gain an optical path between the small-field irradiation and the object to be read. The elevation angle (incident angle) can be increased. Therefore, the amount of light reflected by the bottom surface of the object to be read and traveling toward the total reflection mirror can be sufficiently secured, and a clear image can be displayed by the image pickup system. And in this case, the illumination system and
Place it between the reflection mirror and face the bottom of the object to be read.
To emit light, and the emitted direct light
Large field of view that makes a small elevation angle to the bottom when entering the bottom
Since it is further equipped with lighting, a 30 mm square QFP (Quad
Capable of imaging large read objects such as Flat Package)
And the combination of large-field illumination and small-field illumination
It enables a wide range of reading areas, and it can read objects of various sizes.
Can be reliably imaged by the imaging system.

[0007]

Further, when a light-transmissive dustproof plate is provided in the observation window located near the object to be read, when the large field of view of the object to be read is recognized, the large field illumination is turned on and the small field illumination is turned off. preferable. Therefore, when recognizing the large field of view of the object to be read, the bright spot of the small field illumination reflected by the dustproof plate does not move into the field of view of the image pickup system, and the image recognition system can surely recognize it.

Further, it is preferable that the small visual field illumination is constituted by an illumination light source having a half value angle of 20 degrees or less. When such an illumination light source is used, the amount of light from the light source can be increased, and the amount of reflected light that is reflected by the object to be read and directed toward the total reflection mirror can be further increased, contributing to increased recognition in the imaging system. To do.

Further, it is preferable that the light source is constituted by illumination of a red LED. When such an LED is used, the amount of reflected light increases, and a bright image can be displayed by the image pickup system. Further, by adopting the LED, it is possible to improve the response speed of repeated lighting / extinction, which is effective in improving the recognition speed of the read object.

Further, it is preferable that the light source is constituted by illumination of a blue LED. When such an LED is used, it is possible to reduce the reflection of an object in the background of the read object and prevent erroneous recognition of the image of the read object. Further, by adopting the LED, it is possible to improve the response speed of repeated lighting / extinction, which is effective in improving the recognition speed of the read object.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of an image pickup apparatus according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an image pickup apparatus according to the present invention. The imaging device 1 shown in FIG.
The electronic component (reading target) 2 having a package developed based on the demand for multi-functionality can be imaged, and is incorporated and used as a part of an electronic component mounting device (not shown). The packages include QFP, SOP, SOJ,
Although there are QFJs and the like, in recent years, honing processing for deburring may not be performed on the electronic component 2 due to cost reduction of the electronic component 2. The surface of the electronic component 2 in such a state is close to a mirror surface state, and simply illuminating the electronic component 2 causes a shortage of light amount at the time of imaging. Therefore, the image pickup apparatus 1 that enables the image pickup of the electronic component 2 will be described.

The image pickup apparatus 1 has a casing 3 which constitutes a dark box, and the suction nozzle 4 is provided in the casing 3.
An illumination system 5 for illuminating the bottom surface 2a of the electronic component 2 conveyed to the reading area S is accommodated.
Further, the imaging device 1 is arranged between the illumination system 5 and the imaging system 6 for receiving the light reflected by the electronic component 2 as image information and projecting it as an image of the electronic component 2, and reflecting the light. And a lens system 7 for focusing light on the image pickup system 6.

The image pickup device 1 has a structure for picking up images of electronic components 2 of various sizes in the reading area S, but the position of the bottom surface 2a of the electronic component 2 is always constant in the reading area S. The movement path of the suction nozzle 4 is controlled so that As a result, the bottom surface 2a of the electronic component 2 always maintains a constant work distance W. Specifically, the image pickup apparatus 1 according to the present embodiment includes a small visual field mode for imaging a small electronic component (for example, a capacitor) of 10 mm square or less and a large electronic component of about 10 mm square to 40 mm square (for example, a QFP of 30 mm square). It is divided into two modes, a large field of view for imaging. That is, the lateral body 3 of the casing 3
A half mirror 8 is arranged inside a, and the half mirror 8 distributes the light reflected by the bottom surface 2a of the electronic component 2 and the leads 2b in two directions. Then, one of the reflected lights enters the small-view vertical barrel 3b, and the other reflected light enters the large-view vertical barrel 3c via the reflecting plate 12 for changing the optical path L by 90 degrees. To do.

Further, the reflected light in the vertical barrel 3b for a small field of view is
After passing through the small-field lens unit 9 that constitutes one of the lens systems 7, the small-field CCD 10 that constitutes one of the imaging systems 6
To form an image. Further, the reflected light in the vertical body 3c for a large field of view is
After passing through the large-field lens unit 11 forming the other side of the lens system 7, the large-field CCD 1 forming the other side of the imaging system 6
Image at 2.

The illumination system 5 is also the CCD 1 described above.
Like 0 and 12, it is divided into two modes, a large field mode and a small field mode.

Specifically, on the optical path L between the electronic component 2 and the lens system 7 (between the electronic component 2 and the half mirror 8 in this embodiment), the entire optical path L for bending the optical path L by 90 degrees. The reflection mirror 15 is fixed to the inner wall surface of the horizontal body 3a. In this case, the reflection surface 15a of the total reflection mirror 15 has a tilt angle γ (see FIG. 2) of about 45 degrees in the horizontal barrel 3a with reference to the optical path L between the total reflection mirror 15 and the half mirror 8. It is arranged. And the total reflection mirror 15
And the lens system 7 (in this embodiment, the total reflection mirror 1
A small-field illumination 16 that emits light toward the total reflection mirror 15 is provided between 5 and the half mirror 8.
This small-field illumination 16 is a plurality of LEDs for illuminating a small electronic component (for example, a capacitor) of 10 mm square or less.
Each LED 16a is fixed to the inner wall surface of the horizontal barrel 3a in a state of being arranged so as to surround the optical path L.

The small visual field illumination 16 as described above is an illumination that covers a small visual field, and as shown in FIG.
16 a emits light toward the total reflection mirror 15, and causes indirect light reflected by the total reflection mirror 15 to enter the bottom surface 2 a of the electronic component 2. In this case, the emission optical axis K1 of the light reflected by the total reflection mirror 15 has a large elevation angle (incident angle) α with respect to the reference line A along the bottom surface 2a of the electronic component 2 so that the emission optical axis K1 is emitted. The direction of K is adjusted. The elevation angle α is naturally changed by appropriately changing the angle at which the output optical axis K of the LED 16a is incident on the reflection surface 15a of the total reflection mirror 15, but here, the elevation angle α is reflected by the bottom surface 2a and the lead 2b. As a result of various experiments, the elevation angle α is 70% in order to surely return the reflected light to the total reflection mirror 15.
It was judged that a degree of 90 degrees is appropriate.

As described above, the small-field illumination 16 is an indirect light which is once reflected by the total reflection mirror 15, so that the optical path L between the small-field irradiation 16 and the electronic component 2 can be gained. As a result, the elevation angle (incident angle) of light with respect to the bottom surface 2a of the electronic component 2 can be increased. Therefore, the amount of light reflected by the bottom surface 2a of the electronic component 2 and heading for the total reflection mirror 15 can be sufficiently secured, and even the light that has passed through the half mirror 8 is clear in the small-field CCD 10 to provide a clear image. Can be imaged as.

As shown in FIGS. 1 and 2, a large-field illumination 17 is provided between the electronic component 2 and the total reflection mirror 15 to emit light toward the bottom surface 2a of the electronic component 2.
The large-field illumination 17 is formed at one end of the lateral body 3a of the casing 3 and is provided in the vicinity of the observation window 13 located directly below the reading area S. Specifically, the large-field illumination 17
A plurality of LEDs for illuminating large electronic components (for example, 30 mm square QFP) of about 10 mm square to 40 mm square
Each LED 17a is fixed to the inner wall surface of the horizontal barrel 3a in a state of being arranged so as to surround the optical path L.

The large-field illumination 17 as described above is an illumination that covers a large field of view, and as shown in FIG.
The light 17a is directly incident on the bottom surface 2a of the electronic component 2 as light. In this case, the emission optical axis H of the LED 17a
However, the direction of the LED 17a is adjusted so that the elevation angle (incident angle) β becomes small with respect to the reference line A of the bottom surface 2a of the electronic component 2. Here, in order to surely return the light reflected by the bottom surface 2a and the leads 2b to the total reflection mirror 15, as a result of various experiments, an elevation angle β of 40 ° to 50 ° was appropriate.

Such a large-field illumination 17 is used in the electronic component 2
Since the read area S is illuminated in a wide range, a sufficient amount of light reflected by the electronic component 2 can be secured, and a clear image can be formed by the large-field CCD 12.

Here, as shown in FIG. 1, the casing 3
An observation window 13 is formed at one end of the horizontal body 3a of the device, and the observation window 13 is located directly below the reading area S.
A light-transmissive glass dustproof plate 14 is fitted in the plate 3. In this case, by turning the small field illumination 16, a large in-field for CCD12 performed a large field recognition, glare bright spots of the small field illumination 16 which is reflected by dust-proof plate 14 in its field of view,
It interferes with recognition. Therefore, when recognizing the large visual field, the large visual field illumination 17 is turned on and the small visual field illumination 16 is turned off. When the small-field CCD 10 performs small-field recognition, the large-field illumination 17 and the small-field illumination 16 are turned on at the same time. When the observation window 13 does not have the dustproof plate 14, the large-field illumination 1 is used for both large-field recognition and small-field recognition.
Both 7 and the small-field illumination 16 are turned on at the same time.

Large-field illumination 17 and small-field illumination 1 described above
6 may use a halogen light source, but small field illumination 1
By making 6 an LED having a half-value angle of 20 degrees or less, it contributes to increasing the light amount of the light source, and the bottom surface 2a of the electronic component 2 and the lead
After being reflected by b, the amount of light reflected toward the total reflection mirror 15 is further increased.
It contributes to the recognition up in D10.

The large-field illumination 17 and the small-field illumination 16
Is composed of a red LED, the bottom surface 2a of the electronic component 2
Also, the amount of light reflected by the leads 2b is increased, and a bright image can be displayed by the image pickup system 6. On the other hand, when each of the lights 16 and 17 is formed of a blue LED, the electronic component 2
It is possible to reduce the reflection of the suction nozzle 4 and the like located on the background of the above, and prevent erroneous recognition of the image of the electronic component 2. Further, as an effect of adopting the LED, it is possible to improve the response speed of repeatedly turning on / off the light, and it is possible to improve the recognition speed of the electronic component 2.

[0027]

Since the image pickup apparatus according to the present invention is constructed as described above, the following effects can be obtained. That is, the image pickup apparatus of the present invention includes two illumination systems having a light source by an LED for illuminating a reading object arranged in a reading area with illumination light, and a reading object generated when illuminated by the illumination system. In an imaging device having an imaging system that receives reflected light from the imaging device to image the object to be read, and a lens system that is disposed between the imaging system and the illumination system and forms an image of the reflected light on the imaging system. On the optical path between the object and the lens system, a total reflection mirror that bends this optical path by approximately 90 degrees is arranged. The illumination system is arranged between the total reflection mirror and the lens system, and is directed toward the total reflection mirror. When the indirect light that emits light and is reflected by the total reflection mirror is incident on the bottom surface of the object to be read, small field illumination that makes a large elevation angle with the bottom surface and reading
Place it between the object and the total reflection mirror to
Light is emitted toward the bottom and the emitted direct light is read
When incident on the bottom of the
Since the large-field illumination is provided, the apparatus itself can be downsized and the recognition accuracy of the read object can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an image pickup apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a main part of the image pickup apparatus shown in FIG.

[Explanation of symbols]

S ... Reading area, α, β ... Elevation angle, 1 ... Imaging device, 2 ... Electronic component (object to be read), 2a ... Bottom surface, 5 ... Illumination system, 6
... Imaging system, 7 ... Lens system, 13 ... Observation window, 14 ... Dustproof plate, 15 ... Total reflection mirror, 16 ... Small field illumination, 17 ... Large field illumination, 16a, 17a ... LED (light source).

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01B 11/00-11/30 G01N 21/84

Claims (5)

(57) [Claims] 1. A two having a light source with a reading object which is placed in the reading area LED for illuminating the illumination light
Disposed between the two illumination systems, an imaging system that receives reflected light from the object to be read that is generated when illuminated by the illumination system and images the object to be read, and the imaging system and the illumination system. In an imaging device having a lens system which is formed into an image of the reflected light on the imaging system, an optical path between the object to be read and the lens system,
A total reflection mirror that bends this optical path by about 90 degrees is arranged, the illumination system is arranged between the total reflection mirror and the lens system, and emits light toward the total reflection mirror, and the total reflection mirror. Small-field illumination that makes a large elevation angle with respect to the bottom surface when indirect light reflected by the light enters the bottom surface of the object to be read.
And arranged between the reading object and the total reflection mirror,
Light is emitted toward the bottom surface of the object to be read and is emitted.
Direct light is incident on the bottom surface of the object to be read.
In this case, the imaging device is provided with a large-field illumination that makes a small elevation angle with respect to the bottom surface . 2. When the observation window located near the object to be read is provided with a light-transmitting dustproof plate, the large field illumination is turned on when the large field of view of the object to be read is recognized, and the small field illumination is provided. imaging device according to claim 1, wherein the turning off the. Wherein the small field illumination imaging apparatus according to any one of claims 1-2, characterized in that configured in the following illumination light source half angle 20 °. Wherein the light source, the image pickup apparatus of any one of claims 1-3, characterized in that is constituted by illumination of a red LED. Wherein the light source, the image pickup apparatus of any one of claims 1-3, characterized in that is constituted by illumination of a blue LED.