JP2002170404A - Illumination light source for light guide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination light source for a light guide which has a long life and capable of manufacturing at comparatively low cost, flexibly changes its form of casing in accordance with the space of the installed place, and further obtains sufficient quantity of light required for inspection. SOLUTION: Within the casing 110 are disposed at least two pairs of light- source units 140 as if to enclose a multi-surface reflection mirror 160, with each such pair consisting of a plurality of light-emitting diodes 142 and a concave mirror 141 reflecting and collecting the light from the light-emitting diodes. The light from the foregoing light-source units 140 is reflected on the foregoing respective reflection surfaces 150 so as to be converged on one point and led into the light connector 160.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination light source for a light guide used to illuminate a photographing place when inspecting, for example, the quality of an industrial product or the like on a production line by using an image of a CCD camera or the like. More specifically, the present invention relates to an illumination light source for a light guide using a light emitting diode as a light source.

[0002]

2. Description of the Related Art As a method of inspecting the quality of industrial products such as printed circuit boards and semiconductors, for example, defective soldering, defects, adhesion of foreign substances, etc., on a production line, a method using imaging by a CCD camera or the like has been widely used. ing. In this method, a specific part of a component is imaged, and the presence or absence of an abnormality is inspected by comparing the result with an imaging result of a normal component. In such an inspection method, it is necessary to illuminate the imaging site of the CCD camera brightly and uniformly by a lighting device,
A light guide is known as one of the lighting devices for that purpose.

The light guide converges a large number of optical fibers, makes the light emitted from a light source incident on the base end as a light receiving part, directs the end of the optical fiber to an object to be inspected as an irradiation part, and emits the light from the end of the optical fiber. The illumination device is configured to irradiate the test object with the light to be inspected. In the case of a production line using an inspection method using the image of the CCD camera, when a failure occurs in the lighting device and the inspection becomes impossible, the production line must be stopped.

As a light source of the light guide, a halogen lamp is generally used in many cases.
Since the life of the lamp is as short as about 200 to 1000 hours, and the life of the lamp varies significantly, for example, in a semiconductor production line using hundreds of light guides, it is necessary to prevent the production line from stopping. However, there is a problem that the operator must constantly monitor the lamp so that it can be replaced immediately. In addition, when it is necessary to turn on or off the light during the inspection, there are many problems such as the life of the lamp being remarkably reduced in the halogen light source.

In order to solve such a problem, Japanese Patent Application Laid-Open No. 11-219608 by the present applicant proposes an illumination light source using a light emitting diode. Since the light emitting diode has a long life and does not require lamp replacement, labor saving and improvement in workability can be achieved by the production line.
However, the light emitted by a single light emitting diode is weak and cannot be used as it is as a light source for illumination.
In JP-A-11-219608, light from a light-emitting diode is condensed by a condensing member, and light having sufficient brightness for illumination is obtained.

That is, a truncated cone-shaped light-condensing member made of a light-transmitting material is brought into contact with the light-emitting portions of a plurality of light-emitting diodes supported on the substrate so as to face the same surface, so that the bottom surface whose diameter is enlarged is in contact with the light-emitting portions. And collects light emitted from the plurality of light emitting diodes to obtain light of sufficient brightness for illumination.

[0007]

However, in the technique disclosed in Japanese Patent Application Laid-Open No. H11-219608, it takes time and effort to manufacture and process a transparent member having a truncated cone shape as a light condensing member, and the manufacturing cost is high. In addition, since the transparent member is relatively long, there is a problem that the apparatus cannot be made compact.

Further, the light emitting diode has a weaker light quantity than the halogen lamp, so that a large number of arrangements are required to obtain a light quantity sufficient for illumination required for inspection. For this reason, when a large number of light emitting diodes are arranged on one substrate, there is a problem that the device cannot be made compact because the substrate itself becomes large.

Therefore, an object of the present invention is to provide a lamp that can be manufactured at a relatively low cost without having to replace a lamp with a long service life.
An object of the present invention is to provide an illumination light source for a light guide that can be turned on or off during use without any problem, and that can obtain a sufficient amount of light required for inspection.

[0010]

In order to achieve the above object, an illumination light source for a light guide according to the present invention comprises a plurality of light emitting diodes supported on a substrate and arranged with light emitting portions facing the same surface. And at least two or more light source units each including a concave mirror for reflecting and condensing the light emitted from the light emitting diode, and respectively reflecting the light reflected by the concave mirrors of the two or more light source units at one location. It is characterized by comprising a multifaceted reflecting mirror for emitting light, and an optical connector to which an optical fiber cable is connected, which is arranged at a position where light is collected by the multifaceted reflecting mirror.

According to the present invention, the light emitted from the plurality of light-emitting diodes of each light source unit is reflected by the concave mirror, then re-reflected by the multi-faced mirror and condensed on the optical connector. Light can be efficiently introduced into the light guide optical fiber cable connected to the connector, and a sufficient amount of light can be obtained.

Further, since the light emitting diode has a long life and requires almost no replacement, labor saving and improvement in workability can be achieved by the production line. Furthermore, the life of the light emitting diode is not shortened even if it is frequently turned on and off during use, and the color tone of the light emitting diode can be selected according to the purpose, thereby improving the accuracy of inspection and the like. Can be.

Further, the concave mirror used as the light collecting means is
Due to the simple structure, the manufacturing cost can be kept low and the weight can be reduced. Further, since the light collected by the two or more light source units is collected at one place by the multifaceted reflecting mirror, the light amount can be further increased.

According to a preferred aspect of the present invention, a light extraction hole is formed at the center of the substrate, the light emitting diodes are arranged in a ring around the light extraction hole, and light reflected by the concave mirror is formed. The multi-faceted reflecting mirror is illuminated through the light extraction hole.

According to the above aspect, since the light is irradiated to the multifaceted reflecting mirror through the light extraction hole formed at the center of the substrate, the board, the concave mirror and the multifaceted reflecting mirror are coaxially arranged. It can be made compact.

According to a further preferred aspect of the present invention, a hole is provided in a central portion of the concave mirror, another substrate is arranged on the back side of the concave mirror, and another substrate supported and arranged on the substrate is provided. There is one group of light-emitting diodes, and light emitted from the other group of light-emitting diodes is configured to be directly radiated to the polygon mirror through a light extraction hole of the substrate.

According to the above aspect, the light emitted by another group of light emitting diodes disposed on the back side of the concave mirror is directly radiated to the multifaceted reflecting mirror directly through the light extraction hole of the substrate. The dark portion at the center of the output light obtained by condensing the light emitted by the annularly arranged light emitting diodes is supplemented, and the output light having uniform brightness in the radial direction can be obtained.

According to a further preferred aspect of the present invention, the light emitting diodes are arranged in a plurality of stages on the substrate.

According to the above aspect, since a plurality of light emitting diodes are arranged in at least two stages in the vertical direction on the substrate, a large number of light emitting diodes can be arranged with the same substrate area, and the arrangement density of the light emitting diodes can be reduced. The amount of light can be increased while keeping the size of the apparatus small.

According to a further preferred aspect of the present invention, the concave mirror has a shape in which opposing portions of the circumference are cut by parallel straight lines.

According to the above aspect, the shape of the concave mirror can be made vertically long or horizontally long according to the shape of the casing, so that the installation space can be effectively utilized to the utmost.
For example, since it can be manufactured by cutting both ends from a circular concave mirror, the manufacturing process can be shared with a normal circular concave mirror and the manufacturing cost of the concave mirror can be reduced.

According to a further preferred aspect of the present invention, each surface of the multi-sided reflecting mirror is constituted by a concave curved surface.

According to the above aspect, when the light beams collected from the respective light source units are turned back by the multi-faceted reflecting mirror, the light can be further condensed on the concave curved surface, so that the light can be condensed efficiently.

[0024]

1 to 5 show one embodiment of an illumination light source for a light guide according to the present invention. FIG.
FIG. 2 is a plan view of an illumination light source for a light guide according to the present invention, and FIG.
Is a plan view of a main part of the light source unit, FIG. 3 is a front view of the concave mirror,
FIG. 4 is a front view of the second substrate, and FIG. 5 is a side view of the second substrate.

As shown in FIG. 1, the illumination light source 10 of the present invention
0 has a box-shaped casing 110, a power supply circuit 120 is disposed inside the casing 110, and a cooling fan 130 is disposed in each light source unit 140.

In the casing 110, two sets of light source units 140 are arranged so as to surround the multi-sided reflecting mirror 150, and light from the light source unit 140 is applied to each surface of the multi-sided reflecting mirror 150. It is arranged to be reflected by. The optical connector 160 is provided at a position where the light turned back by the multi-faceted reflecting mirror 150 substantially focuses.

Here, the light source unit 1 shown in FIGS.
Reference numeral 40 denotes a position where the concave mirror 141 faces the first light emitting diode group 142 supported by the first substrate 143. The first substrate 143 has a circular light extraction hole 144 at the center, and the first light emitting diode group 142.
Are arranged annularly around the light extraction hole 144.

Further, it is preferable that the first light emitting diode group 142 is arranged in at least two stages in the vertical direction on the surface of the first substrate 143. In the example shown in FIG. 2, three stages are arranged stepwise. In this case, in order to increase the number of light emitting diodes with the same substrate area, it is preferable to arrange the respective steps so as to partially overlap each other as shown in FIG. 2, whereby the arrangement density of the light emitting diodes can be increased and the amount of light can be increased. .

The concave mirror 1 having a hole 145 at the center
41 is arranged so that its concave surface faces the first light emitting diode group 142. As the concave mirror 141, one obtained by polishing metal such as brass, or one obtained by molding glass or synthetic resin and subjecting the surface to metal evaporation can be used.

The shape of the concave mirror 141 can be adjusted to the casing 110 according to the installation space, and the shape is not particularly limited. For example, a rectangular shape, an elliptical shape, an oval shape, or the like can be appropriately selected according to the casing 110, but is more preferably a shape obtained by cutting opposing portions of the circumference 146 with parallel straight lines 147 as shown in FIG. .
In this case, a molding method in which the metal is pressed in advance to that shape,
It may be processed by resin molding or the like, or may be manufactured by manufacturing a circular concave mirror in the first stage and then cutting both ends.

Further, the second substrate 149 supporting the second light emitting diode group 148 is provided with the second light emitting diode group 148.
The light-emitting portion 8 is connected to and supported on the rear side of the concave mirror 141 so as to face the first light-emitting diode group 142. As shown in FIG. 4, the second light emitting diode group 148 is arranged in a circle at the center of the second substrate 149, and the emitted light is focused on the focal point F of the concave mirror 141 as shown in FIG. It is arranged to be inclined so as to converge light.

Then, as shown in FIG. 2, the second light emitting diode group 148 has a tip portion which is the concave mirror 141.
The light emitted by the second light emitting diode group 148 is directly radiated through the hole 145 toward the multi-sided reflecting mirror 150 as shown by the imaginary line in FIG. It is supposed to be.

The luminous flux collected from each light source unit 140 is then reflected by a multi-sided reflecting mirror 150 so as to be turned back and condensed at one location. Here, a multi-sided reflecting mirror 1
Reference numeral 50 has a number of reflecting surfaces corresponding to the number of light source units 140, and forms a triangular prism in the example of FIG.

Here, as the multifaceted reflecting mirror 150, a mirror-polished metal such as aluminum or brass, or a mirror or glass formed by molding a glass or synthetic resin and subjecting the surface thereof to metal evaporation such as aluminum is preferable. Available to

The base end of a cylindrical optical connector 160 inserted through the casing 110 is disposed at a position where the light beams reflected by the multi-faceted reflecting mirror 150 are substantially gathered. The optical connector 160 has an insertion hole 161 for an optical fiber cable (not shown).

Next, the operation of the illumination light source 100 will be described. First, a predetermined voltage is supplied from the power supply circuit 120 of the illumination light source 100 to the first light emitting diode group 142 via the first substrate 143, and the first light emitting diode group 142 emits light. , A predetermined voltage is supplied to the second light emitting diode group 148, and the second light emitting diode group 148 emits light. Further, the cooling fan 130 is operated, and the first light emitting diode group 1 is turned on.
42 and the second light emitting diode group 148 are prevented from being overheated due to heat generation or the like.

As shown by the imaginary line in FIG. 2, the light emitted from the first light emitting diode group 142 is
Then, the light is reflected by the corresponding reflecting surface of the multi-sided reflecting mirror 150 and condensed on the light guide of the optical connector 160. Here, since the first light emitting diode group 142 is arranged in a ring shape, the central portion of the output light focused on the focal plane tends to be darker than the peripheral edge with the light of only the first light emitting diode group 142. There is.

However, the second light emitting diode group 148
The light emitted from the first light-emitting diode group 142 compensates for the unevenness of the output light of the first light-emitting diode group 142 and is collected at the light guide portion of the optical connector 160 because the light emitted from the first light-emitting diode group 142 passes through the hole 145 of the concave mirror 141 and is directly applied to the multi-sided reflecting mirror 150. The brightness of the emitted output light becomes uniform in the radial direction.

In FIG. 3, since the concave mirror 141 has a shape in which opposing portions of the circumference are cut by parallel straight lines, the entire shape of the casing 110 of the illumination light source device for a light guide is vertically or horizontally elongated. Can be
Since the installation space in the width direction can be narrowed, the apparatus can be made more compact, and can be installed even in a narrow inspection space.

As shown in FIGS. 1 and 2, the light emitting diode groups 131 are arranged in at least two stages in the vertical direction on the surface of the substrate 130, so that a large number of light emitting diodes are arranged on the same substrate area. And the arrangement density can be increased, and the light amount can be increased while the apparatus is downsized.

Further, the light collected by each light source unit 140 is reflected by the multi-sided reflecting mirror 150 so as to be further turned back and condensed in one place, so that the amount of light is comparable to that of a halogen lamp. Can be easily obtained.

Further, by combining a plurality of light source units, even if the number of light emitting diodes is increased, the size of the concave mirror per one can be reduced, so that the degree of freedom of the shape of the casing is increased and the installation space can be used to the maximum. Further, since the concave mirror can always be manufactured in the same size and the total light amount can be determined by the number of light source units, the manufacturing cost can be reduced by using common manufacturing parts.

The condensed output light is emitted from an annular light emitting portion of a light guide (not shown) to a work to be inspected through an optical fiber cable (not shown). The inspection location of the illuminated workpiece is C
An image is taken by a CD camera, and an inspection is performed.

As described above, according to this illumination light source 100, the light collected by at least two or more light source units 140 is turned back by the multi-faceted reflecting mirror 150 and condensed at one place. It is possible to obtain a light quantity comparable to that of the above.

Further, since the light of the plurality of light emitting diodes is condensed using the non-circular concave mirror 150, the work 300
In addition, it is possible to output light having sufficient brightness for the inspection, and to adjust the shape of the concave mirror to the shape of the casing 110, so that the installation space can be effectively used.

Since the life of the light-emitting diode is long, it is not necessary to replace the lamp or the like, so that it is possible to save labor on the production line and to improve workability. In addition, by using the concave mirror 141, the first light emitting diode group 142 can be arranged on the light output side, so that the space inside the device can be effectively used and the entire device can be made compact.

FIG. 6 shows another embodiment of an illumination light source for a light guide according to the present invention. It is to be noted that substantially the same portions as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 6, in this illumination light source for a light guide, four sets of light source units 140 are arranged in a casing 110 so as to surround a multi-sided reflecting mirror 151. Is arranged so as to irradiate the corresponding reflecting surface of the multi-sided reflecting mirror 151. Thus, the difference from the above-described embodiment is that four sets of light source units 140 are used, and the reflecting mirror 151 is formed in a quadrangular pyramid shape in accordance with the use of the four sets.

As a result, the amount of light is about twice as large as that of the above embodiment. As described above, it is possible to freely increase the amount of light by combining the number of light source units and the reflecting mirror. Also, by combining multiple light source units,
Even if the number of light emitting diodes increases, the concave mirror per one can be small, so the degree of freedom of the shape of the casing increases,
Installation space can be maximized. In addition, since the concave mirror can always be manufactured in the same size and the total amount of light can be determined by the number of light source units, the manufacturing process can be simplified and the light source units can be shared, so that the manufacturing cost can be reduced.

On the other hand, FIGS. 7 and 8 show another embodiment of the multifaceted reflecting mirror of the present invention. This embodiment differs from the above in that the surfaces of the multi-sided reflecting mirrors 152 and 153 have concave curved surfaces 152a and 153a, respectively. Generally, a light emitting diode light source has a spread of about 8 to 25 degrees depending on the light source color. Therefore, by making each surface of the multi-sided reflecting mirror a concave surface, not only the light flux from each light source unit 140 is simply reflected and turned back, but also the reflected light is collected again and collected by the optical fiber. Light efficiency can be increased.

Note that the illumination light source of the present invention can be configured as an illumination device to which a light guide is connected in advance and which is supported by a frame integrated with the light guide. In this case, the illumination light source and the light guide are integrated, and the whole is moved according to the inspection location of the work. However, repeated bending stress or the like is not applied to the optical fiber cable of the light guide. Therefore, breakage or the like of the optical fiber cable due to bending fatigue can be prevented.

Further, by selecting a light emitting diode of a desired color, it is possible to output illumination light of a color according to the purpose. In this case, if three light-emitting diodes of RGB are previously mixed and arranged alternately so that only a desired light-emitting diode emits light in accordance with a target color, one illumination light source can output various colors. It is possible.

[0053]

As described above, according to the present invention,
It is possible to provide an illumination light source for a light guide that has a long life, does not require lamp replacement work, can be manufactured at a relatively low cost, and is small and can obtain a sufficient amount of light required for inspection.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of an illumination light source for a light guide according to the present invention.

FIG. 2 is a plan view of a main part of a light source unit in the illumination light source.

FIG. 3 is a front view of a concave mirror in the illumination light source.

FIG. 4 is a front view of a second substrate in the illumination light source.

FIG. 5 is a side view of a second substrate in the illumination light source.

FIG. 6 is a plan view of another embodiment of an illumination light source for a light guide according to the present invention.

FIG. 7 is a perspective view of another embodiment of the reflector in the illumination light source for a light guide according to the present invention.

FIG. 8 is a perspective view of still another embodiment of the reflector in the illumination light source for a light guide according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Illumination light source 110 Casing 140 Light source unit 141 Concave mirror 142 First light emitting diode group 143 First substrate 148 Second light emitting diode group 149 Second substrate 150 Multi-sided reflector 160 Optical connector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01N 21/956 F21Y 101: 02 H01L 33/00 F21S 1/02 G // F21Y 101: 02 1 / 00F F term (reference) 2G051 AA65 AB14 BA02 BA20 BB02 BB17 BB20 5F041 AA06 DC07 DC22 DC23 EE23 FF11

Claims (6)

[Claims] 1. At least two or more light-emitting diodes supported on a substrate and having a plurality of light-emitting diodes arranged with light-emitting portions facing the same surface, and a concave mirror for reflecting and condensing light emitted by the light-emitting diodes. A plurality of light source units, a multi-sided reflecting mirror that reflects the light reflected by the concave mirrors of the two or more light source units and collects the light at one location, Was
An illumination light source for a light guide, comprising: an optical connector to which an optical fiber cable is connected. 2. A light extraction hole is formed at the center of the substrate, the light emitting diodes are arranged in a ring around the light extraction hole, and light reflected by the concave mirror is reflected by the multi-surface through the light extraction hole. 2. The illumination light source for a light guide according to claim 1, wherein the illumination light is applied to a mirror. 3. A hole is provided in the center of the concave mirror, another substrate is disposed on the back side of the concave mirror, and another group of light emitting diodes supported and arranged on the substrate is provided. The illumination light source for a light guide according to claim 2, wherein the light emitted from one group of light emitting diodes is configured to be directly radiated to a multifaceted reflecting mirror through a light extraction hole of the substrate. 4. The illumination light source for a light guide according to claim 1, wherein the light emitting diodes are arranged in a plurality of stages on the substrate. 5. The illumination light source for a light guide according to claim 1, wherein the concave mirror has a shape in which opposing portions of the circumference are cut by parallel straight lines. 6. The illumination light source for a light guide according to claim 1, wherein each surface of the multi-sided reflecting mirror is a concave curved surface.