Inspection lighting device

Abstract

Provided is a lighting device for inspection with which it is possible, using a simple configuration, to broaden the range of distances between an object and the lighting device for inspection at which inspection of the object is possible. This lighting device 1 for inspection comprises: a housing 2 which has an object-side light-transmitting portion 2a and a camera-side light-transmitting portion 2b; and an elongate rigid substrate 3 which is disposed in the housing 2, has a plurality of chip LEDs 30 arranged in a line in the lengthwise direction and soldered to a surface thereof, and is bent into a ring such that said surface is on the inner side. The housing 2 has a light-reflecting layer 21 between the edge of the camera-side light-transmitting portion 2b and the rigid substrate 3. Anode-side soldered portions 34 having respective anode-side terminals of the plurality of chip LEDs 30 soldered thereto and cathode-side soldered portions 35 having respective cathode-side terminals of the plurality of chip LEDs 30 soldered thereto are provided on the surface of the rigid substrate 3. The anode-side soldered portions 34 and the cathode-side soldered portions 35 extend parallel with each other in the lengthwise direction of the of the rigid substrate 3.

Description

Technical Field

[0001] The present invention relates to an inspection lighting device that irradiates an article with light from a plurality of LEDs to inspect the article.

Background Art

[0002] Conventionally, for articles (products) produced in a factory, an inspection is performed by irradiating light from an inspection lighting device having a plurality of LEDs onto the articles conveyed by a belt conveyor or the like and photographing them with a camera (appearance inspection for defects, scratches, dirt, foreign matters, etc.). Various inspection lighting devices are used depending on the articles to be inspected, and some of them irradiate light on the articles from a direction close to the horizontal direction by making the distance (vertical distance) between the inspection lighting device and the article relatively small.

[0003] For example, FIG. 3 of Patent Document 1 discloses an inspection lighting device in which a plurality of bullet-shaped LEDs (light-emitting elements) are arranged in an inward-facing annular shape and slightly inclined toward the article side. This inspection lighting device has a light reflection surface inside the LEDs and on the camera (illumination detection device) side, and irradiates the article with light directly from the LEDs toward the article and light reflected by the light reflection surface and then directed toward the article. Also, FIG. 4 of the same document discloses an inspection lighting device in which a plurality of bullet-shaped LEDs are arranged in an inward-facing annular shape without being inclined toward the article side. This inspection lighting device has no light reflection surface, and a diffuser having a particularly high diffusion ability is arranged inside the LEDs, and the article is irradiated with light from the LEDs passing through this diffuser toward the article. The inspection lighting devices disclosed in FIGS. 3 and 4 as described above inspect parts attached to a substantially flat surface as the articles to be inspected and irradiate light on them from a direction close to the horizontal direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] However, inspection lighting devices such as those disclosed in Figures 3 and 4 of Patent Document 1 are not simple in their configuration, as the LEDs are slightly tilted toward the object, and a diffuser with particularly high diffusion capability is positioned. Furthermore, the range of distance between the inspection lighting device and the object in which inspection of the object is possible is limited.

[0006] This invention has been made in view of the above circumstances, and its purpose is to provide an inspection lighting device that allows for inspection of articles with a simple configuration and enables a wide range of spacing between the inspection lighting device and the article. [Means for solving the problem]

[0007] To achieve the above objective, an inspection lighting device according to an embodiment of the present invention comprises a housing having an article-side light-passing portion and a camera-side light-passing portion, and a long rigid substrate disposed within the housing, on which a plurality of chip LEDs are soldered in a longitudinal direction to its surface and bent into an annular shape so that the surface faces inward, wherein the housing has a light-reflecting layer between the periphery of the camera-side light-passing portion and the rigid substrate, and the surface of the rigid substrate is provided with an anode-side soldering portion to which the anode-side terminal of each of the plurality of chip LEDs is soldered and a cathode-side soldering portion to which the cathode-side terminal of each of the chip LEDs is soldered, and the anode-side soldering portion and the cathode-side soldering portion extend parallel to each other in the longitudinal direction of the rigid substrate.

[0008] The aforementioned light-reflecting layer can be white or mirror-like.

[0009] The rigid substrate can be a glass epoxy substrate or a glass composite substrate on which a conductive pattern is formed.

[0010] The inspection lighting device may further include a heat dissipation sheet that is bent into an annular shape and in contact with the rigid substrate. [Effects of the Invention]

[0011] According to the inspection lighting device of the present invention, it is possible to widen the distance between the inspection lighting device and the article, which allows for inspection of the article, with a simple configuration. [Brief explanation of the drawing]

[0012] [Figure 1A] This is a cross-sectional view (a cross-sectional view at the position indicated by line AA in Figure 1B) showing an inspection lighting device according to an embodiment of the present invention. [Figure 1B] This is a bottom view of the same inspection lighting device, with the housing bottom plate removed. [Figure 2] This is a circuit diagram showing an example of a circuit implemented by the rigid circuit board of the inspection lighting device described above. [Figure 3] This is an external view showing the surface of the rigid substrate before the chip LEDs of the inspection lighting device described above are soldered to it. [Figure 4] This is an explanatory diagram illustrating the light characteristics of the inspection lighting device described above, in a cross-sectional view, and shows the case where the distance between the inspection lighting device and the object is narrow. [Figure 5] This is an explanatory diagram illustrating the light characteristics of the inspection lighting device described above, in a cross-sectional view, and shows the case where there is a wide gap between the inspection lighting device and the object. [Modes for carrying out the invention]

[0013] The following describes embodiments for carrying out the present invention. An inspection lighting device 1 according to an embodiment of the present invention comprises a housing 2 and a rigid substrate 3, as shown in Figures 1A and 1B. The inspection lighting device 1 can be used with an article M to be inspected positioned below and a camera C for photographing the article M positioned above (see Figures 4 and 5 described later). The inspection lighting device 1 has a cable 1a, and the connector 1b of the cable 1a is connected to a dimmer or the like (not shown) for use.

[0014] The housing 2 supports the rigid substrate 3. The housing 2 has an article-side light-passing section 2a through which light passes to the article M side, and a camera-side light-passing section 2b through which light passes to the camera C side. Specifically, the housing 2 can be composed of a housing body section 2c and a housing bottom plate section 2d below it. The article-side light-passing section 2a is formed in the housing bottom plate section 2d. The housing 2 can be a low-height, roughly cylindrical shape. The housing 2 can be made of a metal material such as aluminum or copper, or a resin material.

[0015] The housing 2 has a light-reflecting layer 21 between the periphery of the camera-side light-transmitting portion 2b and the rigid substrate 3. The light-reflecting layer 21 reflects light and is, for example, white or mirror-like. The light-reflecting layer 21 may be attached as a separate component from the rest of the housing 2, or it may be painted onto the housing 2.

[0016] The rigid substrate 3 is located inside the housing 2. The rigid substrate 3 is a long piece of material with multiple chip LEDs 30 soldered to its surface in a longitudinal direction, and bent into an annular shape so that the surface faces inward (see Figure 1B). The rigid substrate 3 is thin enough to be bent into an annular shape. As shown in Figures 1A and 1B, an annular heat dissipation sheet 4 can be provided around the rigid substrate 3. The heat dissipation sheet 4 can be in contact with the rigid substrate 3. Note that in Figures 1A and 1B, the reference numeral 30 for the LED 30 is only shown for the central LED in Figure 1A and the left and right LEDs which are shown in cross-section. In Figure 1A, the sides (thickness direction surfaces) of the LEDs 30 become increasingly visible as they are positioned from the center to the left or right.

[0017] Figure 2 shows a specific circuit example of the rigid board 3. In the example in Figure 2, there are 36 chip LEDs 30 soldered to the rigid board 3, with 12 sets of 3 series-connected chip LEDs 30 connected in parallel. Each set of 3 series-connected chip LEDs 30 is further connected in series with a resistor 31. Each set of 3 series-connected chip LEDs 30 and resistor 31 is connected to power supply wiring connection points 32 and 33, where the positive power supply wiring cord 1aa (more specifically, the conductor within it) and the negative power supply wiring cord 1ab (more specifically, the conductor within it) included in cable 1a are connected by soldering or the like, respectively. Reference numerals 34 and 35 indicate the anode-side soldering point where the anode terminal of the chip LED 30 is soldered, and the cathode-side soldering point where the cathode terminal of the chip LED 30 is soldered, respectively. Reference numerals 36 and 37 indicate the resistor soldering points where the two terminals of the resistor 31 are soldered.

[0018] The rigid substrate 3 is a long substrate in which a conductive pattern is formed on the surface or back surface of the substrate itself, such as a glass epoxy substrate or a glass composite substrate. In the rigid substrate 3, the parts of the conductive pattern to be soldered (soldering parts) are exposed, while the parts other than the soldering parts are covered with solder resist or the like.

[0019] FIG. 3 corresponds to FIG. 2 and shows an example of the specific appearance of the surface of the rigid substrate 3 before the chip LED 30 is soldered. In the example of FIG. 3, the conductor pattern on the surface is shown by a broken line, and the soldering part is shown by a solid line.

[0020] On the surface of the rigid substrate 3, an anode-side soldering part 34 to which the anode-side terminal of the chip LED 30 is soldered and a cathode-side soldering part 35 to which the cathode-side terminal of the chip LED 30 is soldered are provided in the same number as the number of chip LEDs 30 (for example, 36). As shown in FIG. 3, each of the anode-side soldering part 34 and the cathode-side soldering part 35 extends in the length direction of the rigid substrate 3 (the direction in which the long rigid substrate 3 extends) in parallel with each other. In the example of FIG. 3, the widths (dimensions in the direction perpendicular to the length direction) of the anode-side soldering part 34 and the cathode-side soldering part 35 are different from each other, but they may be the same.

[0021] Note that the resistor 31 can be soldered to the resistor soldering parts 36 and 37 provided on the back surface of the rigid substrate 3. Also, the power supply wiring cord connection parts 32 and 33 can be provided on the back surface of the rigid substrate 3. In FIGS. 1A and 1B, the resistor 31 is omitted.

[0022] After soldering components such as the chip LED 30, the rigid substrate 3 is bent in the length direction. At this time, although the rigid substrate 3 is bent with a fairly large curvature, each of the chip LEDs 30 is soldered at the anode-side soldering part 34 and the cathode-side soldering part 35 that extend in the length direction of the rigid substrate 3, so that the stress caused by bending can be relaxed, and as a result, it can be prevented from cracking.

[0023] The rigid circuit board 3 is ring-shaped, with both ends 3a and 3b joined together and placed inside the housing 2 (see Figure 1B). The positive power supply wiring cord 1aa (more specifically, the conductor within it) and the negative power supply wiring cord 1ab (more specifically, the conductor within it) included in the cable 1a are connected to the power supply wiring cord connection points 32 and 33 by soldering or other means. Note that the positions of the joining of both ends 3a and 3b of the rigid circuit board 3 and the positions of the power supply wiring cord connection points 32 and 33 within the housing 2 are not limited to those shown in Figure 1B.

[0024] In the inspection lighting device 1, when voltage and current are supplied through cable 1a (positive power wiring cord 1aa and negative power wiring cord 1ab), current flows through each chip LED 30, and as shown in Figures 4 and 5, light (schematically shown by dashed lines with arrows in Figures 4 and 5) is emitted from multiple LEDs 30 on the rigid substrate 3 at a predetermined directional angle (angle at which the light spreads) centered on the horizontal direction. The object M located below is illuminated by the light from the chip LEDs 30 that goes directly to the object M through the object-side light-passing section 2a and the light that is reflected by the light-reflecting layer 21 and then goes to the object M through the object-side light-passing section 2a. The reflected light from the object M (schematically shown by dashed lines with arrows in Figures 4 and 5) then passes through the object-side light-passing section 2a and the camera-side light-passing section 2b and enters the camera C located above. In this way, the object M is photographed and inspected by the camera C.

[0025] Here, the inspection lighting device 1 can be easily made highly bright by using chip LEDs 30. Furthermore, since the directional angle of the chip LEDs 30 is generally large, the distance G (see Figures 4 and 5) between the inspection lighting device 1 and the item M, where the item M can be inspected, can be widened by the light directed towards the item M and the light reflected by the light reflection layer 21 before being directed towards the item M. It is possible to make the amount of light emitted from the chip LEDs 30 that directly passes through the camera-side light-transmitting section 2b (and leaks out from there) extremely small.

[0026] Thus, the inspection lighting device 1 has a simple configuration and allows for a wide range of spacing G between the inspection lighting device 1 and the item M, enabling inspection of the item M.

[0027] Although an inspection lighting device according to an embodiment of the present invention has been described above, the present invention is not limited to those described in the embodiments, and various design modifications are possible within the scope of the claims. [Explanation of Symbols]

[0028] 1. Inspection lighting device 1a Cable 1aa Positive side power wiring cord 1ab Negative power supply wiring cord 1b connector 2 Housing 2a Article side light passage section 2b Camera-side light passage section 2c Housing main body 2D Housing bottom plate 21 Light reflective layer 3 Rigid substrate 30 Chip LEDs 31 Resistors 32, 33 Power wiring cord connection section 34 Anode-side soldering point 35. Cathode side soldering point 36, 37 Resistor soldering points 3a, 3b Edges of the rigid substrate 4. Heat dissipation sheet C Camera G. Distance between the inspection lighting device and the article. M Goods

Claims

1. A housing having an item-side light-passing section and a camera-side light-passing section, A long rigid substrate is placed inside the housing, on which multiple chip LEDs are arranged lengthwise and soldered to the surface, and which is bent into a ring shape so that the surface faces inward, Equipped with, The housing has a light-reflecting layer between the periphery of the camera-side light-passing portion and the rigid substrate. An inspection lighting device wherein the surface of the rigid substrate is provided with anode-side soldering portions to which the anode-side terminals of each of the plurality of chip LEDs are soldered, and cathode-side soldering portions to which the cathode-side terminals of each of the plurality of chip LEDs are soldered, and each of the anode-side soldering portions and each of the cathode-side soldering portions extends parallel to each other in the longitudinal direction of the rigid substrate.

2. In the inspection lighting device according to claim 1, The aforementioned light-reflecting layer is white or mirror-like in the inspection lighting device.

3. In the inspection lighting device according to claim 1 or 2, The rigid substrate is an inspection lighting device in which a conductive pattern is formed on a glass epoxy substrate or a glass composite substrate.

4. In the inspection lighting device according to any one of claims 1 to 3, An inspection lighting device further comprising a heat dissipation sheet that is bent into an annular shape and in contact with the rigid substrate.

Images