JP7329801B2 - Surface illumination device for inspection - Google Patents

Description

The present invention relates to an inspection surface illumination device for irradiating planar light onto an article for inspecting the article.

2. Description of the Related Art Conventionally, articles (products) produced in a factory have been inspected (appearance inspection for defects, scratches, stains, foreign matter, etc.) by irradiating them with light from an inspection lighting device and photographing them with a camera. The inspection illumination device includes a light-emitting substrate body having a light-emitting element array portion in which a plurality of light-emitting elements (usually, LEDs) are arranged two-dimensionally. There is a device that irradiates the surface (surface illumination device for inspection).

For example, a planar illumination device for inspection disclosed in Patent Document 1 uniformly irradiates planar light onto the entire tablet, which is an article. Light transmitted through the tablet is captured by a camera, which compares the tablet's shape and area with reference data to determine if it is defective. Further, the surface illumination device for inspection shown in, for example, FIG. 6 of Patent Literature 2 irradiates planar light onto an article having a film formed on the surface thereof. The light reflected off the article is photographed by a camera, thereby detecting film thickness unevenness of the film.

JP-A-8-21805 JP 2013-108775 A

By the way, since the intensity of the light emitted from the surface illumination device for inspection decreases at the edges, it is necessary to provide a reflecting mirror around the light emitting element arrangement portion to increase the area where a certain uniformity can be obtained. It is also done. Also, a general power supply wiring cord is normally used for the wiring of the power supply from the outside to the light emitting substrate. In addition, the light-emitting element is often of a thin surface-mounted type. In such a case, the height at which the light is emitted with a predetermined directivity (the height above the board) is low, so the power supply Sometimes it is not easy to do the wiring.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to maintain uniformity of emitted light over a wide range even when a thin surface-mounted light-emitting element is used, and to reduce power supply wiring. To provide an inspection surface illumination device capable of easily performing

In order to achieve the above object, the surface illumination device for inspection according to claim 1 comprises a light emitting element array portion in which a plurality of light emitting elements are two-dimensionally arrayed and surface-mounted on a substrate; a light emitting substrate body having two power terminal portions and a first notch formed in a portion of an end portion of the substrate near the two power terminal portions; A reflecting mirror provided on the periphery and having a second notch formed in a part of the lower portion thereof, and two power supply wiring cords, the two power supply wiring cords radiating from the light emitting element array section are connected to the two power supply terminals through the second notch of the reflecting mirror and the first notch of the substrate so as not to interfere with the light that is about to be reflected by the reflecting mirror. ing.

According to a second aspect of the present invention, there is provided an inspection surface illumination device according to the first aspect, wherein the first notch is formed at a corner of the substrate.

Claim 3 is the inspection surface illumination device according to claim 1 or 2, wherein at least one of the power supply wiring cords is one of the portions located in the first notches. portion is in contact with the lower surface of the reflecting mirror.

According to the surface illumination device for inspection of the present invention, even if a thin surface-mounted light-emitting element is used, it is possible to easily wire the power supply while maintaining uniformity of emitted light over a wide range. .

1 is a plan view of a surface illumination device for inspection according to an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view of the surface illumination device for inspection taken along the cross-sectional plane indicated by AA in FIG. 1; FIG. 10 is an enlarged perspective view showing the vicinity of the first notch of the light-emitting substrate body of the inspection surface illumination device same as above, in which (a) does not omit illustration of two power supply wiring cords, etc.; (b) omits illustration of two power wiring cords and the like. FIG. 3 is a circuit diagram showing a circuit configuration of a light-emitting substrate of the inspection surface illumination device; FIG. 11 is a plan view showing the vicinity of the first notch of the light-emitting substrate body of the same inspection surface illumination device in an enlarged manner, in which (a) is an inner side of the edge of the first notch and the insulator is In (b), the insulator is stripped outside the edge of the first notch, and in (c), part of the insulator is on the lower surface of the reflector. It is something that touches. FIG. 4 is a luminance distribution diagram showing experimental results of light (a luminance distribution diagram of a portion corresponding to a corner where power supply wiring is performed), in which (a) is obtained by the inspection surface illumination device according to the embodiment of the present invention; 1 and (b) are obtained by the surface illumination device for inspection for comparison.

DETAILED DESCRIPTION OF THE INVENTION Embodiments for carrying out the present invention will be described below. As shown in FIG. 1, an inspection surface illumination device 1 according to an embodiment of the present invention includes a housing 2, a light emitting substrate 3, a reflecting mirror 4, and two power wiring cords 5A and 5B. Moreover, the inspection surface illumination device 1 usually includes a diffusion plate 6 as shown in FIG. In FIG. 1, for the convenience of illustration, the diffuser plate 6 positioned on the near side such as the light emitting substrate 3 is shown through. 1 and 2 (and FIGS. 3 and 5, which will be described later), the illustration of a resistor 31b for current limiting, which will be described later, is omitted.

The housing 2 is provided with a light emitting substrate 3 and a reflecting mirror 4 therein. Housing 2 can have a variety of shapes and configurations. From the side of the housing 2, a cable 5, which consists of two power supply wiring cords 5A and 5B connected by an external covering (sheath) 5C (see FIG. 3(a)), protrudes. A connector 5</b>D is attached to the end of the cable 5 . The connector 5D is connected to a dimming power supply device for controlling dimming of the inspection surface illumination device 1, and the like. 3 (and FIG. 5, which will be described later), illustration of the housing 2 and the diffusion plate 6 is omitted.

The light emitting substrate body 3 has a light emitting element array portion 31 . In the light-emitting element array portion 31, a plurality of light-emitting elements (usually LEDs) 31a are two-dimensionally arrayed (in FIG. 1, two-dimensional array of eight horizontally (horizontally) and nine vertically). The light emitting element 31 a is surface-mounted on the substrate 30 . The light emitting element 31a emits light with a predetermined directivity from its surface. Although the thickness of the light emitting element 31a is not particularly limited, it is, for example, about 0.25 mm to about 1 mm. Note that the specific number and arrangement of the light emitting elements 31a can be varied in accordance with the specifications of the surface illumination device 1 for inspection.

In the light-emitting element array section 31, for example, as shown in FIG. 4, a predetermined number of light-emitting elements 31a are connected in series with a current limiting resistor 31b, and the series bodies are connected in parallel in a predetermined number of columns. The number of light emitting elements 31a is not particularly limited, and is determined according to specifications.

As shown in FIGS. 3B and 4, the light emitting substrate body 3 has two power terminal portions 32A and 32B formed on the substrate 30, and two power wiring cords are attached to them. 5A and 5B are connected. The two power supply terminal portions 32A and 32B are usually lands, pads, or parts of patterns formed on the substrate 30 as shown in FIG. 3(b). A current flows through one power terminal portion 32A, the light emitting element 31a of the light emitting element array portion 31, and the other power terminal portion 32B in this order (see FIG. 4). The inspection surface illumination device 1 is normally dimmed by controlling the period during which the current flows by a dimming power supply device or the like.

Further, the light-emitting substrate body 3 has a first notch 33 formed in a part of the end portion of the substrate 30 (see FIG. 3B). The first notch 33 is provided near the two power terminal portions 32A and 32B. The first notch 33 is formed at one of the corners of the substrate 30 in FIG. , when there are a plurality of cables 5, it is possible to form a plurality of them together with a second notch 41 of the reflecting mirror 4, which will be described later.

The reflecting mirror 4 is provided around the light emitting element array portion 31 . Specifically, the reflector 4 is erected inside along the edge of the substrate 30 and surrounds the light emitting element array portion 31 . Normally, four reflecting mirrors 4 surround the light emitting element array portion 31 . The reflecting mirror 4 can have a reflecting layer of silver, white, or the like for reflecting light. The reflecting mirror 4 can increase the area where a certain uniformity of the light emitted from the inspection surface illuminating device 1 can be obtained.

A second notch 41 is formed in a part of the lower portion of the reflecting mirror 4 (see FIG. 3(b)). The shape and size of the second notch 41 are not particularly limited, but may be a shape and size that match the outer covering 5C of the cable 5 .

The two power supply wiring cords 5A and 5B have a structure in which conductors 5Aa and 5Ba and insulators 5Ab and 5Bb covering them are provided. The outer diameter (thickness) of the two power wiring cords 5A and 5B is, for example, about 1 mm to about 2 mm. The two power supply wiring cords 5A and 5B are generally covered with an outer covering 5C to a little inside the second notch 41 of the reflector 4 (see FIG. 3(a)). The two power wiring cords 5A and 5B are connected to the two power terminal portions 32A and 32B through the second notch 41 of the reflector 4 and the first notch 33 of the light emitting substrate 3, Wiring of the power supply is carried out accordingly.

Insulators 5Ab and 5Bb of the two power supply wiring cords 5A and 5B are stripped near edge portions (outline portions) 33A and 33B of the first notch 33, and conductors 5Aa and 5Ba are separated into two pieces. It is connected to the power terminal portions 32A and 32B by soldering or the like. As a result, the two power supply wiring cords 5A and 5B do not extend long above the substrate 30 in a state where the insulators 5Ab and 5Bb are not stripped off, so that the two power supply wiring cords 5A and 5B are not separated from the substrate 30 and floated up. , the height from the substrate 30 can be easily lowered.

The position where the insulators 5Ab and 5Bb are stripped off is inside the edges 33A and 33B of the first notch 33 (inside the substrate 30), as shown in FIG. 5(a) (and FIG. 5(c)). ), or, as shown in FIG. If the insulators 5Ab and 5Bb are stripped outside the edges 33A and 33B of the first notch 33 (that is, if the insulators 5Ab and 5Bb are all stripped off on the substrate 30, ), since only the conductors 5Aa and 5Ba remain on the substrate 30, it is possible to lower the height from the substrate 30 of the power supply wiring cords 5A and 5B as a whole.

Also, both or one of the two power supply wiring cords 5A and 5B (both in FIG. 5(c)) is part of the portion located in the first notch 33 (specifically, one part of the insulators 5Ab and 5Bb). ) is in contact with the lower surface of the reflecting mirror 4, it is further prevented from floating away from the substrate 30, so that the height from the substrate 30 can be further reduced. Note that the lower surface of the reflecting mirror 4 is not in contact with the substrate 30 at the first notch 33 (it is in contact with the substrate 30 except at the first notch 33).

In the inspection surface illuminating device 1 configured as described above, the light emitted from the light emitting element arrangement portion 31 is emitted from the housing either directly or after being reflected by the reflecting mirror 4 . Here, the two power supply wiring cords 5A and 5B can easily wire the power supply using a general power supply wiring cord, and the height from the substrate 30 can be lowered. Then, even if the light emitting element 31a is thin, the two power supply wiring cords 5A and 5B can prevent the light emitted from the light emitting element arrangement portion 31 and being reflected by the reflecting mirror 4 from being blocked. , the uniformity of the light emitted from the inspection surface illumination device 1 can be maintained over a wide range.

The inventor of the present application made a prototype of the surface illumination device 1 for inspection and conducted experiments on the light emitted from it. For comparison, the same experiment was conducted with a comparative inspection plane illumination device similar to the inspection plane illumination device 1 except that it did not have the first notch 33 . The light-emitting substrate 3 used has a two-dimensional array of light-emitting elements 31a of 8 in width and 9 in length. has an outer diameter of 1.05 mm.

As a result of the experiment, the surface illumination device 1 for inspection maintains a certain uniformity of light over a wide range even at the corner where the power supply wiring is performed, as shown in FIG. 6(a). On the other hand, in the comparison inspection surface illumination device, as shown in FIG. 6B, the light has a narrow range of uniformity at the corner.

Although the inspection surface illuminating device according to the embodiment of the present invention has been described above, the present invention is not limited to the one described in the embodiment, and can be variously modified within the scope of the claims. Design changes are possible.

REFERENCE SIGNS LIST 1 surface illumination device for inspection 2 housing 3 light emitting substrate 30 substrate 31 light emitting element arrangement portion 31a light emitting element 31b resistor 32A, 32B power supply terminal portion 33 first notch 33A, 33B edge of first notch 4 reflector 41 second notch 5 cable 5A, 5B power wiring cord 5Aa, 5Ba conductor 5Ab, 5Bb insulator 5C outer cover 5D connector

Claims (3)

a light emitting element array portion in which a plurality of light emitting elements are two-dimensionally arranged and surface-mounted on a substrate; and two power supply terminal portions formed on the substrate; a light-emitting substrate body having a first notch formed in a part of an end portion of the substrate;
a reflecting mirror provided around the light emitting element arrangement portion and having a second notch formed in a part of the lower portion thereof;
two power wiring cords;
with
The two power supply wiring cords are arranged between the second notch of the reflecting mirror and the first cutout of the substrate so as not to interfere with the light emitted from the light emitting element array portion and about to be reflected by the reflecting mirror. a surface illumination device for inspection connected to the two power supply terminals through the cutouts of In the inspection surface illumination device according to claim 1,
The inspection surface illumination device, wherein the first notch is formed at a corner of the substrate. In the inspection surface illumination device according to claim 1 or 2,
A surface illumination device for inspection, wherein a portion of the at least one power wiring cord located in the first notch is in contact with the lower surface of the reflecting mirror.

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