JP4721733B2 - Imaging device - Google Patents

Description

  The present invention particularly relates to an imaging apparatus used in the process of mounting an electronic component on a circuit board.

  Conventionally, there is JP-A-6-61700 as a technique in such a field. The imaging device described in this publication is provided with illumination means for irradiating illumination light to a lead portion of an electronic component, and an optical fiber is used as the illumination means. The light emitted from the optical fiber illuminates the lead part of the electronic component. At this time, the electronic component can be illuminated from below by indirect illumination using a reflecting surface formed in a staircase shape.

JP-A-6-61700 (FIG. 1) Japanese Patent Laid-Open No. 10-27513

  However, in the conventional imaging device described above, the light from the optical fiber is reflected by the step-like reflecting surface, thereby creating diffused indirect light, enabling a wide range of illumination, and widening by one type of light source. Although the range can be illuminated uniformly, there is a problem that it is difficult to deal with a wide variety of electronic components because the indirect illumination is single.

  An object of the present invention is to provide an imaging apparatus that creates efficient indirect illumination and facilitates handling according to the type of an object to be read.

An imaging apparatus according to the present invention receives illumination light arranged in a housing for illuminating a reading object with illumination light emitted from an imaging window, and reflected light from the reading object that is generated when illuminated by the illumination means. In an imaging apparatus having imaging means for imaging a reading object,
The lighting means consists of direct lighting and indirect lighting,
The indirect illumination is arranged on the imaging unit side so as to be separated from the first illumination unit along the imaging axis extending from the imaging unit to the imaging window along with the first illumination unit arranged in the vicinity of the imaging window. A second illuminator, a first reflector that is fixed to the housing and reflects light emitted from the first illuminator toward the imaging window; A second reflecting unit that reflects light from the illumination unit toward the imaging window and shields stray light from the first illumination unit toward the imaging axis,
The direct illumination is arranged on the imaging means side so as to be separated from the second illumination unit, and a third illumination unit composed of LEDs arranged in an annular shape around the imaging axis, and the outside of the third illumination unit And a fourth illumination unit arranged at equal intervals in the circumferential direction on the side ,
The first reflection unit is provided so as to surround the imaging window in the housing, and the second reflection unit is configured to shield stray light that travels toward the imaging axis from the light emitted from the first illumination unit. It is provided so that it may fall down to the 1st illumination part side .

In this imaging apparatus, the light emitted from the first illumination unit is reflected by the first reflection unit, and then illuminates the reading target, creating first indirect illumination that illuminates the reading target. The light emitted from the second illumination unit is reflected by the second reflection unit and then illuminates the object to be read, creating second indirect illumination that illuminates the object to be read. Of the two indirect illuminations, when stray light generated in the first illumination unit near the imaging window directly hits the object to be read, this adversely affects imaging. Therefore, if the light emitted from the first illumination unit and traveling toward the imaging axis is shielded by the second reflection unit described above, stray light generated in the first illumination unit is directly applied to the reading object. It becomes difficult to hit. Therefore, efficient indirect illumination is created, and as a result, illumination unevenness that causes erroneous recognition of an object to be read is less likely to occur. As described above, by appropriately combining the turning on / off of the two types of indirect illumination, it is possible to easily cope with an appropriate response according to the type of the object to be read.
Furthermore, the third illumination unit in the imaging apparatus enables direct illumination of the reading object arranged on the imaging axis, but in order to enable simultaneous imaging of a plurality of reading objects, the imaging axis line is set. When imaging a plurality of objects to be read arranged at the center, variations in illumination are likely to occur only with the third illumination unit. Therefore, the direct illumination has a fourth illumination unit arranged at equal intervals in the circumferential direction outside the third illumination unit, separately from the third illumination unit. With this fourth illumination unit, the illumination area can be equally divided in the circumferential direction, and illumination can be assigned to each reading object, thereby enabling simultaneous imaging of a plurality of reading objects. It improves imaging efficiency and facilitates handling according to the type of object to be read.

In addition, the first reflection unit is provided so as to surround the imaging window in the housing, and the second reflection unit shields stray light that travels toward the imaging axis from the light emitted from the first illumination unit. in, that provided so as to fall down in the first illumination unit side. As described above, the first reflecting portion surrounds the imaging window, so that the first reflecting portion can be formed integrally with the housing, and the second reflecting portion falls to the first illumination portion side. The stray light generated from the first illumination unit can be appropriately prevented. Then, by adjusting the reflection angle between the first reflecting portion and the second reflecting portion appropriately, the illumination adjustment is performed so that the first indirect illumination and the second indirect illumination complement each other in the indirect illumination. And the occurrence of uneven illumination can be suppressed.

  In addition, the illumination elevation angle of the second indirect illumination created by the cooperation of the second illumination unit and the second reflection unit is the first produced by the cooperation of the first illumination unit and the first reflection unit. It is preferable that it is larger than the illumination elevation angle of the indirect illumination. By using the first indirect illumination at a shallow angle and the second indirect illumination at a deep angle, uniform illumination over a wide range is possible.

  According to the present invention, efficient indirect illumination is created, and correspondence according to the type of an object to be read is facilitated.

  Hereinafter, preferred embodiments of an imaging apparatus according to the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 4, the imaging device 1 is used by being incorporated as a part of an electronic component mounting machine (not shown), and electronic components (not shown) are mounted on a circuit board (not shown). It is used for the inspection of the electronic component 6 in the stage before mounting the imaging object 6). The electronic component 6 is packaged in accordance with demands for miniaturization, thinning, and diversification. As this package, peripheral lead type package, surface mount type area array package, QFP, SOP, SOJ, QFJ, There are BGA and CSP. An imaging apparatus 1 that images such an electronic component 6 has a vertically long casing 2, and an approximately octagonal imaging window S is provided on the top of the housing 2. The electronic component 6, which is an example of an object to be read, is conveyed to the position of the imaging window S by a suction nozzle (not shown), and the electronic component 6 is illuminated from below by the illumination means 10.

  Further, the imaging apparatus 1 includes imaging means 5 for receiving the light reflected from the bottom surface of the electronic component 6 and imaging the electronic component 6. The imaging means 5 is composed of a CCD camera and is arranged directly below the illumination means 10 so that the imaging axis L passes through the center of the imaging window S. The imaging means 5 includes an imaging lens unit 8 and an area CCD 9, and is arranged so that the imaging lens unit 8 can be seen through an opening 2b formed in a drive circuit board 49 fixed to the housing 2. Yes.

  The illumination means 10 used as the illumination of the imaging means 5 has an indirect illumination 10A and a direct illumination 10B. The illumination means 10 can be adapted to various electronic components 6 while being reduced in size as a unit. The indirect illumination 10A includes an upper first indirect illumination 20 and a lower second indirect illumination 30, and the direct illumination 10B includes an upper first direct illumination 40 and a lower second direct illumination 50. Become.

  First, the indirect illumination 10A will be described.

  The first indirect illumination 20 located on the upper stage side is formed integrally with the first illumination unit 21 disposed closest to the imaging window S and the upper part of the housing 2, and is from the first illumination unit 21. The first reflecting portion 22 reflects light toward the electronic component 6. The first indirect illumination 20 constitutes the proximity illumination closest to the imaging window S, and has a relatively small illumination elevation angle α (for example, 8 to 30 degrees), that is, a shallow angle α, for example, a ball grid (for the lead portion) of the electronic component 6A. Example) Illuminate 6a indirectly from the side. On the other hand, the second indirect illumination 30 located on the lower stage side, the second illumination unit 31 disposed on the imaging means 5 side so as to be separated from the first illumination unit 21 along the imaging axis L, It consists of the 2nd reflection part 32 which is fixed to the housing | casing 2 and reflects the light from the 2nd illumination part 31 toward the imaging window S. As shown in FIG. The second indirect illumination 30 indirectly illuminates, for example, a ball grid (an example of a lead portion) 6a of the electronic component 6A from obliquely below with a relatively large illumination elevation angle β (for example, 30 to 60 degrees), that is, a deep angle β. .

  The first reflecting portion 22 in the first indirect illumination 20 arranged so as to define the imaging window S includes a flat plate-like long reflecting plate 22a and a flat plate-like short reflecting plate 22b. By combining the reflectors 22a and 22b, an octagonal imaging window S is formed at the upper end of the housing 2 (see FIGS. 1 and 2). Each of the reflection plates 22a and 22b has a predetermined angle with respect to the imaging axis L and reflects light with a relatively small illumination elevation angle α. For example, the ball grid 6a of the electronic component 6A is indirectly illuminated.

  Further, the first illumination unit 21 in the first indirect illumination 20 includes a large number of LEDs 21 a arranged so as to surround the imaging axis L so as to be along the side wall 2 a of the housing 2. The LEDs 21 a of the first illumination unit 21 are arranged directly below the reflecting plates 22 a and 22 b and arranged in a line on an annular base plate 33 fixed to the housing 2. Each LED 21 a emits light parallel to the imaging axis L toward the first reflecting portion 22.

  On the other hand, each LED 31 a of the second illumination unit 31 in the second indirect illumination 30 is fixed to the drive circuit board 35 screwed to the side wall 2 a of the housing 2. Each LED 21a emits light toward a flat reflector 34 formed as a part of the second reflector 32, and the four reflectors 34 have a predetermined angle with respect to the imaging axis L. Then, light is reflected with a relatively large illumination elevation angle β, for example, the ball grid 6a of the electronic component 6A is indirectly illuminated.

  Further, of the two indirect illuminations 20 and 30, unnecessary light generated by the first illumination unit 21, that is, stray light P, is the electronic component 6 because the first illumination unit 21 is close to the imaging window S. If it hits directly, it has a great influence on imaging. Therefore, as shown in FIGS. 4 and 5, in the second reflecting portion 32, each reflecting plate 34 is integrally fixed to the upper end of the base portion 36 bent in a crank shape, and the first reflecting portion 34 is also fixed to the first reflecting portion 34. It arrange | positions so that it may fall down to the 1st illumination part 21 side so that the stray light P which goes to the imaging-axis line L side among the lights radiate | emitted from each LED21a of the illumination part 21 may be shielded. In order to achieve this light shielding, the reflecting plate 34 is disposed so as to be close to and opposed to the first illumination unit 21 and is tilted so as to have a predetermined angle with respect to the imaging axis L. The electronic component 6 is irradiated only with the light that passes through the opening R formed by the first reflecting portion 22 and the second reflecting portion 32.

  Therefore, the light path from the first illumination unit 21 to the first reflection unit 22 is ensured by the cooperation of the reflection plate 34 and the reflection plates 22a and 22b, and at the same time, stray light generated in the first illumination unit 21 is obtained. P hardly hits the electronic component 6 directly, and as a result, illumination unevenness that causes erroneous recognition of the electronic component 6 is less likely to occur. Further, by changing the reflection angle of the reflecting plate 34, the illumination elevation angle β can be easily and reliably changed. As a result, in the imaging region W, the first indirect illumination 20 is replaced by the second indirect illumination 30. Can be easily complemented. If the first indirect illumination 20 with a small illumination elevation angle α and the second indirect illumination 30 with a large illumination elevation angle β are used, uniform illumination over a wide range is possible, and efficient indirect illumination can be created. Further, by appropriately combining the turning on / off of the two types of indirect illuminations 20 and 30, it becomes easy to cope with the type of the reading object 6 such as an electronic component.

  Next, the direct illumination 10B will be described.

  As shown in FIGS. 1 to 3 and 6, the direct illumination 10 </ b> B includes an upper first direct illumination 40 and a lower second direct illumination 50.

  The first direct illumination 40 located in the upper stage is configured by a fifth illumination unit 41 including a large number of LEDs 41 a arranged so as to surround the imaging axis L along the side wall 2 a of the housing 2. Each LED 41a of the fifth illumination unit 41 is fixed to the drive circuit board 35, and each LED 41a illuminates the electronic component 6 from below at a predetermined illumination elevation angle (for example, 30 to 60 degrees).

  Furthermore, the second direct illumination 50 located in the lower stage is a third illumination unit 51 including a large number of LEDs 51 a arranged in an annular shape so as to surround the imaging axis L on the drive circuit board 49 forming the bottom plate of the housing 2. And the fourth illumination unit 52 arranged at equal intervals in the circumferential direction outside the third illumination unit 51. The third illumination unit 51 is disposed on the imaging means 5 side so as to be separated from the second illumination unit 31. Each LED 51a has a low directivity, is arranged in a double ring shape, and illuminates the electronic component 6 from substantially directly below with a predetermined illumination elevation angle (for example, 60 to 90 degrees).

  The third illumination unit 51 enables illumination of the electronic component 6 </ b> A (see FIG. 3) arranged on the imaging axis L, but a plurality (six) of the six (6) arranged annularly around the imaging axis L. When imaging the electronic component 6 </ b> B (see FIG. 3), variations in illumination are likely to occur only with the third illumination unit 51. This is particularly problematic when the electronic component 6B has a high surface reflectance.

  Therefore, the direct illumination 10B is provided with a fourth illumination unit 52 different from the third illumination unit 51, and the fourth illumination unit 52 corresponds to a set of six electronic components 6B. There are six sets of five LEDs 52a, and they are arranged with a distribution angle of 60 degrees so as to correspond to each electronic component 6B. As this LED 52a, a highly directional LED is used, which enables spot-like illumination. Therefore, the illumination area can be equally divided by the fourth illumination unit 52, and illumination can be evenly assigned to each electronic component 6B. Therefore, a plurality of (in this case, six) electronic components 6B can be simultaneously used. Imaging becomes possible. As a result, the imaging efficiency is improved, and even when the surface reflectance of the electronic component 6B is high, it is easy to cope with the type of the electronic component 6B.

  In the case of an electronic component 6A (see FIG. 3) having a wide work area among the electronic components 6, in the direct illumination 10B, the third illumination unit 51 and the fourth illumination unit 52 are simultaneously turned on. Thus, direct illumination that covers the entire work area becomes possible. In this case, the indirect illumination 10A is also appropriately turned on as necessary.

  Needless to say, the present invention is not limited to the embodiment described above, and the first illumination unit (indirect illumination) 21, the second illumination unit (indirect illumination) 31, the third illumination unit (direct illumination) 51, and the first illumination unit. The simultaneous lighting or selective lighting of the fourth illumination unit (direct illumination) 52 and the fifth illumination unit (direct illumination) 41 is appropriately selected depending on the type of electronic component.

It is sectional drawing which shows one Embodiment of the imaging device which concerns on this invention. It is a perspective view which shows the illumination means applied to the imaging device of FIG. It is a top view of the illumination means shown in FIG. It is sectional drawing which shows the principal part of an illumination means. It is a perspective view which shows a 2nd reflection part. It is a top view which shows the 3rd and 4th illumination part in direct illumination.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging device, 2 ... Housing, 5 ... Imaging means, 6, 6A, 6B ... Electronic component (reading object), 10 ... Illuminating means, 10A ... Indirect illumination, 10B ... Direct illumination, 20 ... First indirect Illumination, 21 ... first illumination unit, 22 ... first reflection unit, 30 ... second indirect illumination, 31 ... second illumination unit, 32 ... second reflection unit, 51 ... third illumination unit, 52: Fourth illumination unit, α, β: illumination elevation angle, L: imaging axis, S: imaging window, P: stray light.

Claims (2)

Illumination means arranged in a housing to illuminate the reading object with illumination light emitted from the imaging window, and reflected light from the reading object generated when illuminated by the illuminating means to receive the reading object In an imaging apparatus having imaging means for imaging
The illumination means comprises direct illumination and indirect illumination,
The indirect lighting is
A first illumination unit disposed in proximity to the imaging window;
A second illumination unit disposed on the imaging unit side so as to be separated from the first illumination unit along an imaging axis extending from the imaging unit to the imaging window;
A first reflection unit fixed to the housing and reflecting light emitted from the first illumination unit toward the imaging window;
Fixed to the housing, reflects light from the second illumination unit toward the imaging window and shields stray light from the first illumination unit toward the imaging axis. And a second reflecting portion that
The direct illumination is
A third illuminating unit that is arranged on the imaging means side so as to be separated from the second illuminating unit, and is formed of LEDs arranged in an annular shape around the imaging axis;
A fourth illumination unit arranged at equal intervals in the circumferential direction outside the third illumination unit ,
The first reflecting portion is provided so as to surround the imaging window in the housing,
The second reflecting portion is provided so as to fall down to the first illuminating portion side so as to shield stray light traveling toward the imaging axis side among the light emitted from the first illuminating portion. An imaging apparatus characterized by that. The illumination elevation angle of the second indirect illumination created by the cooperation of the second illumination unit and the second reflection unit is created by the cooperation of the first illumination unit and the first reflection unit. The imaging apparatus according to claim 1 , wherein the imaging apparatus is larger than an illumination elevation angle of the first indirect illumination.

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