JP4112064B2 - Optical path adjusting member and lighting device including the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical path adjusting member capable of adjusting an optical path by refracting illumination light from a light source, and an illumination device including the optical path adjusting member.
[0002]
[Prior art]
As is well known, in the industrial field, for example, when a CCD camera or sensor is used to recognize an object such as a mark or electronic component on a printed circuit board, light is applied to the object and its vicinity. An illumination device that illuminates the object is used.
FIG. 9 shows an example of a conventional lighting device. In the illumination device 50, a CCD camera 41 for recognizing the object 39 is attached to the upper center of the case 42, and an illumination light source unit 32 having a plurality of light sources 34 (for example, light bulbs and LEDs) is disposed below the CCD camera 41. Has been. At the center of the illumination light source 32, a hole 32a for taking in reflected light from the object is formed.
In the illumination device according to this conventional example, as indicated by solid line arrows in FIG. 9, a part of the light emitted from each light source 34 of the illumination light source unit 32 is irradiated to the object 39, and the reflected light thereof is reflected. The light passes through the hole 32a and is taken into the CCD camera 41. In this conventional illumination device 50, when used, all the light sources 34 of the illumination light source unit 32 are turned on, and light is uniformly irradiated toward the object 9.
[0003]
By the way, in recent years, materials having various surface states have been used and various surface treatments have been applied to mark portions, electronic parts, and the like on printed circuit boards as objects. And various improvement is added also in the illuminating device so that favorable recognition can be performed corresponding to various surface states of various objects.
FIG. 10 shows an illumination light source unit of an illumination apparatus according to another conventional example. In the illumination light source section 52, a large number of light sources 53 are arranged on a plurality of circumferences having different diameters (that is, concentrically), and the light quantity can be adjusted for each light source group on the same circumference. ing. Then, the light amount of the light source 53 is adjusted for each circumferential unit in order to irradiate the illumination light optimal for recognizing the target object according to the surface state of the target object.
[0004]
[Problems to be solved by the invention]
However, even in an illuminating device including such an illumination light source unit 52, if the light amount of each light source 53 selected to be lit is not sufficient, the illuminance necessary for recognizing the object cannot be obtained, and the recognition rate decreases. Or misdetection.
Further, since all the light sources 53 are mounted in the same direction on the same plane, the light irradiation angle depends on the directivity of the light source 53, and sufficient illuminance can be obtained at the desired irradiation angle. difficult. For this reason, for example, it is conceivable to increase the illuminance by increasing the number of light sources 53 or the light quantity of each light source 53. In this case, however, the current consumption increases and the stability of the illuminance decreases due to the heat generated by the light source 53. Or the life of the light source 53 may be shortened.
On the other hand, it is conceivable that the mounting angle of the light source 53 can be made variable so that the illumination angle can be set arbitrarily. In this case, however, the structure of the apparatus becomes complicated and large, leading to an increase in cost. Become. In addition, the adjustment of the irradiation angle is actually complicated and not easy, and there is a problem that it is not practical.
[0005]
The present invention has been made in view of the above technical problem, and it is possible to irradiate an object with suitable illumination light with a simple structure without increasing the number of light sources and the light quantity of each light source. It is an object of the present invention to provide an optical path adjusting member that can be used and an illumination device including the same.
[0006]
[Means for Solving the Problems]
In the invention according to claim 1 of the present application (hereinafter referred to as the first invention), at least one of the light entrance surface and the light exit surface is divided into a plurality of small regions having different refractive indexes, and the object to be irradiated with illumination light. It is arranged between an object and an illumination light source unit that irradiates illumination light toward the object, and the illumination light incident from the illumination light source unit is refracted at different refractive indexes in each of the small regions and emitted. By condensing the emitted light to a predetermined area including the object ,
At least one of the incident surface and the exit surface of the illumination light is partitioned into a plurality of small strip-shaped regions that are concentric, and the refractive index on the exit side of these strip-shaped small regions is set to be smaller toward the center. It is a thing.
[0008]
Furthermore, an invention according to claim 2 of the present application (hereinafter referred to as a third invention) is characterized in that the light passage surfaces of the plurality of small regions are each constituted by a part of a curved surface having a different curvature. It is a thing.
[0009]
Furthermore, in the invention according to claim 3 of the present application (hereinafter referred to as the fourth invention), both the incident surface and the exit surface of the light are partitioned into a plurality of small regions having different refractive indices, Both of the light passing surfaces are constituted by a part of a convex curved surface.
[0010]
The invention according to claim 4 of the present application (hereinafter referred to as the fifth invention) is characterized in that the light exit surface of each of the small regions is formed in a polished glass shape.
[0011]
Furthermore, an invention according to claim 5 of the present application (hereinafter referred to as a sixth invention) includes an illumination light source unit having at least one light source, and the illumination light from the illumination light source unit is applied to the surface of a predetermined object. An illumination device for irradiating, comprising the optical path adjusting member according to any one of claims 1 to 4 .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the embodiment is applied to a recognition illumination device in an electronic component mounting apparatus that mounts electronic components or the like on a printed circuit board. .
FIG. 1 is a perspective view schematically showing an overall configuration of an electronic component mounting apparatus 1 according to an embodiment of the present invention. The electronic component mounting apparatus 1 recognizes, for example, a positioning mark 9 attached to a predetermined position on the printed circuit board 14 that has been conveyed into the apparatus, and performs component mounting on the printed circuit board 14. A recognition illumination device 10 for illuminating the mark 9 when the mark 9 is recognized is provided. As the surface state of the mark 9 to be recognized, various modes such as a solder coated on the surface (so-called solder mark) can be considered.
The illumination device 10 is incorporated in the head unit 15 together with a CCD camera (not shown) that images the mark 9. The head unit 15 is controlled by an x-direction drive unit 17 constituting a part of the xy two-axis robot and y-direction drive units 18A and 18B that move the x-direction drive unit 17 in the y-axis direction. The illuminating device 10 can freely move above the printed circuit board 14 as the head unit 15 is driven.
[0013]
2 and 3 are a longitudinal sectional view and an exploded perspective view showing the overall configuration of the lighting device 10, respectively. In this illuminating device 10, a CCD camera 11 for recognizing an object is attached to an upper center of a cylindrical case 12, and an illuminating light source unit 2 including a plurality of light sources 3 on a base plate 4 is disposed below the CCD camera 11. ing. An optical path adjusting plate 5 for adjusting the optical path of the irradiation light from the light source 3 is attached to the lower part of the case 12 using a bolt member 13 on the emission side facing the illumination light source unit 2. Yes. In this embodiment, the optical path adjustment substrate 5 is disposed in the vicinity of the illumination light source unit 2 so that illumination light from the light source 3 can be taken in efficiently. At the center of the base plate 4 and the optical path adjusting plate 5 of the illumination light source unit 2, reflection from a mark (not shown) attached on a printed circuit board as an object to which illumination light is irradiated when the apparatus is used. Holes 4a and 5a for allowing light to pass through are formed. In FIG. 3, in order to avoid complication of the drawing, the light source 3 is partially omitted.
[0014]
In the illuminating device 10 having the above configuration, a part of the light from each light source 3 of the illumination light source unit 2 is irradiated onto the printed circuit board, and the reflected light passes through the hole portions 4a and 5a and is then CCD. Captured by the camera 11. The CCD camera 11 is connected to the image recognition device 16, and the reflected light from the recognition object captured by the CCD camera 11 is transmitted to the image recognition device 16 as an electric signal to perform predetermined image processing. Is recognized as an image.
[0015]
FIG. 4 shows an arrangement state of a plurality of light sources 3 in the illumination light source unit 2. In this embodiment, for example, a white LED is used as the light source 3. As can be seen from the drawing, these light sources 3 are arranged on a disc-shaped base plate 4 on a plurality of circumferences having different diameters (that is, concentric circles), so that four light source groups 3A, 3B, 3C and 3D are arranged. Is configured. At this time, the light source group 3A located on the innermost circumference is disposed along the hole 4a provided in the center of the base plate 4, and the light source group 3D located on the outermost circumference is the base plate. 4 will be arranged along the peripheral edge. The light sources 3 constituting the light source groups 3A to 3D are arranged perpendicular to the base plate 4 and are aligned with the optical path adjusting plate 5 attached to the lower side of the illumination light source unit 2.
In the illumination light source unit 2, the light sources 3 are arranged concentrically so that illumination light with uniform illuminance is emitted from all directions with respect to the optical axis of the CCD camera 11. As long as illuminance light is obtained, the light may be arranged in any manner.
[0016]
5a to 5c show the optical path adjusting plate 5 used in the present embodiment. 5a to 5c are a plan view, a perspective view, and a cross-sectional explanatory view of the optical path adjusting plate 5, respectively. The optical path adjusting plate 5 is formed in a disk shape with a transparent acrylic resin, for example. The exit surface of the illumination light is partitioned into three concentric strip-like small regions 6, 7 and 8, and each of these small regions 6, 7 and 8 has a plane direction of the optical path adjusting plate 5. Light passing surfaces 6a, 7a and 8a having different angles are formed. Further, the optical path adjusting plate 5 is provided with a hole 5b extending in the center direction from the peripheral surface in order to receive the bolt member 13 (see FIG. 2) when attached to the case 12.
[0017]
In the optical path adjusting plate 5, the light passage surface 6 a of the small region 6 located on the innermost side on the light emitting surface forms a surface substantially parallel to the planar direction of the optical path adjusting plate 5. On the other hand, the light passing surfaces 7 a and 8 a of the small regions 7 and 8 located outside the surface are inclined at a predetermined angle with respect to the planar direction of the optical path adjusting plate 5. In the present embodiment, the inclination angle of the light passage surface 7a in the small region 7 is set smaller than that of the light passage surface 8a in the small region 8 outside.
In this embodiment, the maximum depth of each of the small regions 7 and 8 excluding the innermost small region 6 is set to 1 mm and the maximum width is set to about 3 mm. Moreover, although the thing made from a transparent acrylic was used as the said optical path adjustment board 5, it is not limited to this, For example, you may use the optical path adjustment board which consists of transparent or translucent glass or plastics.
[0018]
Next, the light condensing action by the optical path adjusting plate 5 of the illumination device 10 will be described with reference to FIG.
As shown in FIG. 6, when all the light sources 3 of the illumination light source unit 2 are turned on, in the illumination device 10, as shown by a solid line arrow, a small region located on the outermost side of the optical path adjustment plate 5. The light incident from directly above 6C is refracted by the angle θ at the light passage surface 6c. In addition, light incident from above the small region 6B is refracted by an angle φ on the light passage surface 6b. As described above, in this optical path adjusting plate 5, since the inclination angle of the light passage surface 6b is set smaller than that of the light passage surface 6c on the outer side, the refraction angle φ at this light passage surface 6b is , Smaller than the refraction angle θ at the light passage surface 6c.
On the other hand, light incident from directly above the small area 6A located on the innermost side of the optical path adjusting plate 5 is not refracted by the light passage surface 6a (that is, at a refraction angle of 0 °). pass.
As a result, the light of the illumination light source unit 2 that has passed through the optical path adjusting plate 5 is condensed on a predetermined region on the surface facing the illumination device 10. That is, in this illuminating device 10, the light from the illumination light source unit 2 is condensed via the optical path adjusting plate 5, so as to face the illuminating device 10 and on the optical axis of the CCD camera 11 (see FIG. 2). It is possible to irradiate a suitable illumination light to the printed circuit board 14 and the mark 9 attached thereon. Further, in this embodiment, the optical path adjusting plate 5 is disposed in the vicinity of the illumination light source unit 2, and the illumination light is efficiently taken in from the predetermined number or light amount of the light sources 3 and collected in the mark 9. Can be lighted.
[0019]
As described above, in the illumination device 10 according to the present embodiment, the number of light sources and the amount of light of each light source are not increased, and a complicated structure for adjusting the optical path of illumination light is not required. Illumination light suitable for recognizing an object such as the mark 9 attached to can be irradiated.
In the illumination device 10, a part of the light source 3 in the illumination light source unit 2 is turned on or off, or the light amount of the light source 3 is changed according to the surface state of the printed circuit board 14 and the mark 9 attached thereto. It is also possible to make settings that can be performed.
[0020]
In the above-described embodiment, the optical path adjusting plate 5 is partitioned into three small regions 6, 7 and 8 on the light exit surface, but is not limited to this, and there are two or more than three. You may divide into a small area. In particular, when the light is divided into more than three small regions, different refractive indexes are set for the light passage surfaces of the small regions, and the light from the illumination light source unit is refracted at different refraction angles on each light passage surface. By doing, the light from an illumination light source part can be more effectively condensed with respect to objects, such as a printed circuit board and the mark attached | subjected on it. As a result, illumination light suitable for recognizing the object can be emitted.
[0021]
FIG. 7 shows a modification of the optical path adjusting plate. In this optical path adjusting plate 25, for each of a plurality of small strip-like regions 26 that form concentric circles, the light passing surface 26a is constituted by a part of a curved surface having a different curvature. The refractive indexes of these small regions 26 are set to be smaller as they are closer to the center. When this optical path adjusting plate 25 is used, the light from the illumination light source unit is directed to the printed circuit board and an object such as a mark provided thereon at each point on each light passage surface 26a. Refracted into Thereby, the light from an illumination light source part can be finely condensed with respect to objects, such as a mark attached | subjected on the printed circuit board and it.
[0022]
FIG. 8 shows another modification of the optical path adjusting plate. In this optical path adjusting plate 27, both the incident surface and the exit surface of the illumination light are partitioned into strip-shaped small regions 28, 29, and 30 that form concentric circles. Each of the band-like small regions has light passing surfaces 28a, 29a, and 30a having different refractive indexes. Of these, the light passing surfaces 29a and 30a are constituted by a part of a convex curved surface. The refractive indexes of the small regions 28, 29, and 30 are set to be smaller as they are closer to the center. The light path adjusting plate 27 has a larger light collecting effect than a plate having a small area formed only on one side, and is more effective for a printed circuit board and an object such as a mark attached thereon. Illumination light can be condensed.
Although not particularly shown, each light passage surface of the optical path adjusting plate may be processed into a satin finish (that is, a polished glass with a rough surface). In this case, after diffusing the light from the illumination light source part within a range in which the light collection effect by each light passage surface having a predetermined refractive index is maintained, the predetermined region including the object may be irradiated. it can.
[0023]
Furthermore, although white LED was used as the light source 3 of the said illumination light source part 2 in embodiment mentioned above, it is not limited to this, You may use a fluorescent lamp or a light bulb. Further, as the light source 3, a light source that emits light having different colors and wavelengths may be used. In selecting the light source, a light source having a suitable color and wavelength corresponding to the surface state of the printed circuit board or the mark attached thereto is selected so that a clear image can be obtained by the CCD camera 11. Also good.
Furthermore, when a filter member is disposed between the object and the illumination light source unit for the purpose of obtaining illumination light having a desired color or wavelength, for example, the filter member is processed. The optical path adjusting member may also be used.
[0024]
Needless to say, the present invention is not limited to the illustrated embodiment, and various improvements and design changes can be made without departing from the scope of the invention.
[0025]
【The invention's effect】
As is clear from the above description, according to the first invention, the optical path adjusting member is divided into a plurality of small regions having different refractive indexes at least one of the incident surface and the exit surface of the illumination light, and the illumination light is Arranged between an object to be irradiated and an illumination light source unit that irradiates illumination light toward the object, and refracts illumination light incident from the illumination light source unit with a different refractive index in each of the small regions. Since the emitted light is condensed on a predetermined region including the target object, a complicated structure for adjusting the optical path of the illumination light can be obtained without increasing the number of light sources and the light quantity of each light source. Without requiring, it is possible to collect illumination light from a plurality of directions with respect to the object and irradiate with illumination light suitable for recognizing the object.
[0026]
According to the first aspect of the invention, at least one of the light incident surface and the light exit surface is partitioned into a plurality of small band-like regions that are concentric, and the refractive index on the emission side of these belt-like small regions is close to the center. Since it is set so small, illumination light passing through each small region can be condensed toward the center side.
[0027]
Furthermore, according to the third invention, the light passage surfaces of the plurality of small regions are each constituted by a part of a curved surface having a different curvature, so that the light from the illumination light source unit is transmitted to each light passage surface. At each point, the light can be refracted so as to be directed toward the object, and the light can be finely focused on the object.
[0028]
Still further, according to the fourth aspect of the invention, both the light incident surface and the light exit surface are partitioned into a plurality of small regions having different refractive indexes, and both light passing surfaces of the small regions are both convex curved surfaces. Since it is constituted by a part, it is possible to obtain a larger light collection effect by utilizing refraction on both sides.
[0029]
According to the fifth aspect of the invention, since the light exit surface of each small region of the optical path is formed in a polished glass shape, the light from the illumination light source unit is transmitted by each light passage surface having a predetermined refractive index. It is possible to irradiate a predetermined region including the object after diffusing within a range in which the light collecting effect is maintained.
[0030]
Further, according to the sixth aspect is provided with the optical path adjusting member described in any one of claims 1 to 4, effectively condenses the illumination light to the object, Appropriate illumination light can be applied to recognize the object.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an overall configuration of an electronic component mounting apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory view of a longitudinal section of a lighting device provided in the mounting apparatus.
FIG. 3 is a perspective view of the lighting device.
FIG. 4 is a plan view of an illumination light source unit in the illumination device.
FIG. 5A is a plan view of an optical path adjusting member in the illumination device.
(B) It is a perspective view of the said optical path adjustment member.
(C) It is sectional explanatory drawing along the XX line in FIG. 5a.
FIG. 6 is a cross-sectional explanatory view showing a light collection state on the recognition target object during illumination of the recognition target object by the illumination device.
FIG. 7 is a partial cross-sectional explanatory view of an optical path adjusting member having a light passage surface curved for each small region.
FIG. 8 is an explanatory cross-sectional view of an optical path adjusting member partitioned into a plurality of small regions on both sides.
FIG. 9 is a cross-sectional explanatory view showing a light collection state on a recognition target object during illumination of the recognition target object by a conventional illumination device.
FIG. 10 is a plan view of an illumination light source unit in another conventional illumination device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Mounting apparatus 2 ... Illumination light source part 3 ... Light source 5 ... Optical path adjustment member 6, 7, 8, 26, 28, 29, 30 ... Small area | region 6a, 7a, 8a, 26a, 28a, 29a, 30a ... Light passage surface 9 ... object 10 ... lighting device 14 ... printed circuit board

Claims (5)

At least one of the light incident surface and the light exit surface is partitioned into a plurality of small regions having different refractive indexes, and between an object to be irradiated with illumination light and an illumination light source unit that emits illumination light toward the object The illumination light incident from the illumination light source unit is refracted and emitted at different refractive indexes in the respective small regions, thereby condensing the emitted light on a predetermined region including the object ,
At least one of the incident surface and the exit surface of the illumination light is partitioned into a plurality of small strip-shaped regions that are concentric, and the refractive index on the exit side of these strip-shaped small regions is set to be smaller toward the center. An optical path adjusting member.   2. The optical path adjusting member according to claim 1, wherein the light passage surfaces of the plurality of small regions are each constituted by a part of a curved surface having a different curvature. Both the incident surface and the exit surface of the illumination light are divided into a plurality of small regions having different refractive indexes, and both light passing surfaces of each small region are both formed by a part of a convex curved surface. optical path adjusting member according to claim 2 Symbol mounting to. The light path adjusting member according to any one of claims 1 to 3 , wherein the light exit surface of each of the small regions is formed in a polished glass shape. It is an illuminating device provided with the illumination light source part which has at least 1 light source, and irradiates the illumination light from this illumination light source part on the surface of a predetermined target object, Comprising: It is described in any one of the said Claim 1 to 4 An illumination device comprising an optical path adjusting member.

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