JPH08106808A - Lighting system - Google Patents

Abstract

PURPOSE: To improve illumination efficiency by providing a holding means which holds plural light emitting means around an image pickup area so that emitted light axes are directed toward the image pickup area. CONSTITUTION: An opening 21A for interposing the tip portion of a CCD camera 3 thereinto is set at the tip portion of an LED holder 21 which is formed by shaping a rigid body such as aluminum, black bakelite, or the like into hollow circular cone body-like. Plural LED's l are fitted to the inside face 21B of the holder 21 so that the LED's 1 are respectively positioned on the plural steps circumferences around the center axis of the holder 21, and so that emitted light axes K1 are respectively directed toward inside the near side one half area out of the image pickup area AR of the CCD camera 3 on the surface of an inspection board 4. (Emitted lights L1 emitted from the respective LED's 1 form spots in the half area near side to the LED's 1 out of the area AR.) Thereby, the respective light emitting means (LED's) 1 illuminate inside the area AR of the image pickup means (camera) 3 efficiently so as to be capable of improving illumination efficiency.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology (FIG. 4) Problems to be Solved by the Invention (FIGS. 4 to 5B) Means for Solving Problems (FIGS. 1 to 3) Actions (FIGS. 1 to 3) ) Example (FIGS. 1 to 4) Effect of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device, and is suitable for application to, for example, an illuminating device used in a mounting board appearance inspection device for inspecting the appearance of an inspection board.

[0003]

2. Description of the Related Art Conventionally, in a mounting board visual inspection apparatus, for example, a CCD camera or the like is used to sequentially image the surface of an inspection board, each image data thus obtained, and each standard image input in advance. By successively comparing the data with each other, it is possible to detect a soldering defect, a conductor pattern formation defect, or the like. By the way, in such a mounting board appearance inspection apparatus, an illuminating device for illuminating the inside of the imaging area on the surface of the inspection board by the CCD camera is usually arranged near the tip of the CCD camera.

As one of such illuminating devices, conventionally,
As shown in FIG. 4, a plurality of LEDs (light emitting diodes) 1
Are held on the same plane by the LED holder 2 and radially around the tip of the CCD camera 3, and
Some diffusers 5 are arranged so as to be located between the LED holder 3 and the inspection board 4.

[0005]

However, in the case of the illuminating device 6 configured as described above, most of the emitted light L1 emitted from the LED 1 near the tip of the CCD camera 3 (inner peripheral portion) is on the surface of the inspection substrate 4. Imaging area A of CCD camera 3
Emitting light L emitted from the LED 1 that reaches the inside of R but is located away from the tip of the CCD camera 3 (outer periphery).
The amount of light that the light beam No. 1 reaches the above-mentioned image pickup area AR is extremely small, which causes a problem that the illumination efficiency of the device 6 as a whole is poor. In order to solve this problem, conventionally, as shown in FIG.
There has been proposed a method of mounting the optical axis (hereinafter, referred to as an emission optical axis) K1 of the LED holder 2 on the LED holder 2 so that the optical axis K1 faces the imaging area AR of the CCD camera 3.

According to this method, since the LED 1 on the outer peripheral portion can efficiently illuminate the image pickup area AR of the CCD camera 3, there is an advantage that the illumination efficiency of the apparatus 6 as a whole can be improved. However, according to this method that has been conventionally proposed, the LED 1 on the outer peripheral portion of each of the L-shaped emission optical axes K1 serves as a light source in the imaging area AR of the CCD camera 3.
The emission light L1 (FIG. 4) of the LED 1 at the outer peripheral portion is directed so as to be directed to the inside of the half region on the other side with respect to ED1.
It is attached to the LED holder 2 so as to form spots on the other half side of the imaging area AR of the CCD camera 3 with respect to ED1.

However, since the spot of the emitted light from the LED generally has a high brightness portion and a low brightness portion depending on the light distribution characteristic of the emitted light, it is constructed as shown in FIG. 5 (A). In the lighting device 6, as shown in FIG. 5 (B), the spot 10 of the emitted light L1 emitted from each LED 1 on the outer peripheral portion includes the high brightness portion 10B and the low brightness portion 10A. Imaging area A of CCD camera 3
There was a problem that uneven light intensity occurred in R.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a lighting device having high lighting efficiency.

[0009]

In order to solve such a problem, in the present invention, the surface of the inspection object 4 is imaged by a predetermined imaging means 3 and the inspection object 4 is obtained based on the image information thus obtained. Inspection object 4 of inspection device to inspect
In a lighting device that illuminates the imaging area AR of the imaging means 3 on the surface of the plurality of light emitting means 1, each light emitting means 1
Around the image pickup area AR of the image pickup means 3 and the emission optical axis K1
And a holding means 21 for holding so as to face the imaging area AR.

Further, in the present invention, the holding means 21 is
Each of the light emitting means 1 is held so that the emission optical axis K1 faces the inside of an approximately half region of the imaging area AR on the front side with respect to each light emitting means 1 serving as a light source.

Further, in the present invention, the light emitting means 1 is
A light emitting diode is used.

Further, in the present invention, the diffusing means 23 is provided between the surfaces of the light emitting means 1 and the inspection object 4 and diffuses the light L1 emitted from each of the light emitting means 1.

Further, in the present invention, each holding means 21
The light emitting means 1 is held so as to be positioned on a plurality of circles having different diameters with the imaging optical axis K10 of the imaging means 3 as an axis.

Further, according to the present invention, the surface of the inspection object 4 of the inspection device for inspecting the inspection object 4 on the basis of the image information obtained by imaging the surface of the inspection object 4 by the predetermined image pickup means 3. In the illuminating device for illuminating the imaging area AR of the imaging means 3 in FIG.
And the holding means 21 for holding each light emitting means 1 around the image pickup area AR in a stepwise manner along the image pickup direction of the image pickup means 3.

Further, in the present invention, the holding means 21 is
It is a rigid body having an inner side surface 21B that is inclined from the inner peripheral portion toward the outer peripheral portion and holds each light emitting means 1 respectively.
It was attached to the inner surface 21B.

Further, in the present invention, each light emitting means 1
On the inner surface 21B of the holding means 21 respectively.
Is attached to the holding means 21 so that it is embedded to the same height as the inner side surface 21B.

Further, in the present invention, the light emitting means 1 is
A light emitting diode is used.

Further, in the present invention, the diffusing means 23 is provided between the surfaces of the light emitting means 1 and the inspection object 4 and diffuses the light L1 emitted from each light emitting means 1.

Further, in the present invention, each holding means 21
The light emitting means 1 is held so as to be positioned on a plurality of circles having different diameters with the imaging optical axis K10 of the imaging means 3 as an axis.

Further, in the present invention, the holding means 21
The light emitting means 1 is held so that the emission optical axis K1 faces the image pickup area AR of the image pickup means 3, respectively.

[0021]

The light emitting means 1 is held around the image pickup area AR of the image pickup means 3 so that the emission optical axis K1 faces the image pickup area AR. It is possible to illuminate the image pickup area AR, and thus it is possible to realize an illumination device with high illumination efficiency.

Further, since each light emitting means 1 is held in a step shape around the image pickup area AR along the image pickup direction of the image pickup means 3, each light emitting means 1 is held on the surface of the inspection object 4. The light emitting means 1 on the outer peripheral portion can be brought closer to the image pickup area AR of the image pickup means 3 as compared with the case where the light emitting means 1 is held in parallel. Therefore, as compared with the case where each light emitting means 1 is held parallel to the surface of the inspection object 4, the light emitting means 1 at the outer peripheral portion can efficiently illuminate the image pickup area AR of the image pickup means 3,
Thus, a lighting device with good lighting efficiency can be realized.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. 4 are designated by the same reference numerals, 20 indicates an illuminating device which is used as a whole in a mounting board appearance inspection device, and a rigid body such as aluminum or black bake is a hollow cone. An opening 21 </ b> A into which the tip of the CCD camera 3 is inserted is provided at the apex of the LED holder 21 formed by forming the LED holder 21. The inner surface 21B of the LED holder 21 has a plurality of LEDs.
1 is located on each of a plurality of stages of circles centered on the central axis of the LED holder 21, and the emission optical axis K1 is in front of the imaging area AR of the CCD camera 3 on the surface of the inspection substrate 4. The emission light L1 emitted from each of the LEDs 1 is directed toward the inside of the half area on the side (i.e., in the imaging area AR of the CCD camera 3).
ED1 to form spots in the front half of the area).

As a result, the lighting device 20 shown in FIG.
As shown in (A) and (B), each emission light L1 emitted from each LED 1 forms a drop-shaped spot 10 formed on the surface of the inspection substrate 4 at the center of the imaging area AR of the CCD camera 3. 2C, the unevenness of the light intensity in the image pickup area AR of the CCD camera 3 due to the spots 10 of the respective emitted lights L1 emitted from the respective LEDs 1 is suppressed, and as shown in FIG.
The interior can be illuminated with a uniform illuminance. A hollow conical diffuser plate 23 is mounted between the LED holder 21 and the surface of the inspection board 4 so as to be parallel to the inner surface 21B of each LED holder 21. This causes each LED 1 to emit light. The emitted light L1 can more reliably prevent unevenness in light intensity from being generated on the surface of the inspection substrate 4.

In the case of this embodiment, the spread of the emitted light L1 increases as going from the uppermost stage (innermost circumference) to the lowermost stage (outermost circumference) of the LEDs 1 arranged on each stage of the LED holder 21. Each one is selected and used. This is the LE that is arranged in each stage as it goes up.
Since the number of D1 is small, it is necessary to increase the amount of light that one LED1 illuminates the imaging area AR of the CCD camera 3 in the stage where the number of LEDs1 is small, while one LED1 is required in the stage where the number of LED1 is large. This is because it is possible to reduce the amount of light that illuminates the imaging area AR, so that the imaging area AR of the CCD camera 3 can be illuminated with an equal amount of light from each stage.

In practice, the lighting device 20 shown in FIG.
As shown in, the LED1 that emits the emitted light L1 with a spread of about ± 4 [° / oct] is used in the uppermost stage,
At the lowermost stage, the LED 1 which emits the emitted light L1 with a spread of about ± 15 [° / oct] is used.

Further, in the case of this embodiment, as shown in FIG. 3B, each LED 1 has its light emitting point P1 at the same height as the surface of the inner surface 21B of the LED holder 21. 21B so as to be embedded. This is, for example, as shown in FIG.
If each LED 1 is fixed on the surface of the inner side surface 21B of the D holder 21, wobble may occur in the attached LED 1, and each L 1 may be fixed as shown in FIG.
If the ED1 is completely embedded inside the LED holder 21 except for the tip portion, the emitted light L1 emitted from each LED 1 may be reflected on the surface of the hole 21BX in which each LED 1 of the LED holder 21 is embedded. Is.

Therefore, in this lighting device 20, each LED is
1 is attached to the LED holder 21 as shown in FIG. 3 (B) to prevent wobble of each LED 1 and the emitted light L1 emitted from each LED 1 from being reflected on the surface of the hole 21BX. In this way, the durability and the lighting effect are improved.

In the above-described structure, in the illumination device 20, the LED holder 21 is formed in a conical shape so that each LED 1 is arranged around the image pickup area AR on the surface of the inspection substrate 4 of the CCD camera 3 in the CCD camera 3. It can be held in a step shape that is open along the imaging direction of. Therefore, as compared with the conventional illumination device 6 as shown in FIG. 4, the LEDs 1 at the outer peripheral portion (lower stage) and the intermediate portion can be brought closer to the imaging area AR on the surface of the inspection substrate 4 of the CCD camera 3, so that the outer peripheral portion And each LED1 in the middle is efficiently C
The imaging area AR of the CD camera 3 can be illuminated.

Further, in this case, each LED 1 is mounted on the LED holder 21 such that the emission optical axis K1 faces the direction of the image pickup area AR of the CCD camera 3 on the surface of the inspection substrate 4, so that each LED 1 can be CC efficiently.
The image pickup area AR of the D camera 3 can be illuminated. Further, in this case, the emission optical axis K1 of each LED1
Of the image pickup area AR on the surface of the inspection substrate 4 of the CCD camera 3 so that the LED is directed toward the front half area.
Each LE is attached to the holder 21.
The spot 10 of the emitted light L1 emitted from D1 is a CCD
By overlapping in the central portion of the image pickup area AR of the camera 3, it is possible to illuminate the inside of the image pickup area AR with a uniform luminous intensity.

According to the above construction, since the LED holder 21 is formed in a conical shape, the LEDs 1 on the outer peripheral portion and the inner peripheral portion can efficiently form the image pickup area AR on the surface of the inspection substrate 4 of the CCD camera 3. It is possible to illuminate, and thus it is possible to realize a lighting device with good lighting efficiency.

Further, each LED 1 is attached to the LED holder 21 so that the emission optical axis K1 faces the imaging area AR direction of the CCD camera 3 on the surface of the inspection substrate 4, so that each LED 1 can efficiently image the CCD camera 3. The area AR can be illuminated, and thus the illumination efficiency can be further improved.

In the above-mentioned embodiment, the case where the LED holder 21 is formed in the shape of a hollow cone is described, but the present invention is not limited to this, and the point is that the LED is used.
1 can be held around the image pickup area AR of the CCD camera 3 on the surface of the inspection substrate 4 in a stepwise manner that is open in the image pickup direction of the CCD camera 3, the embodiment is used as a holding means for holding each LED 1. The LED holder 21 may have a shape other than the inner side surface 21B similar to the peripheral side surface of the conical body, and various other shapes can be applied as the shape of the holding means for actually holding the LED 1.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the illuminating device 20 of the mounting board appearance inspection device has been described, but the present invention is not limited to this, and other various inspection devices. It can be applied as a lighting device.

Further, in the above-mentioned embodiment, the case where the LED 1 is applied as the light emitting means has been described, but the present invention is not limited to this, and various other light emitting means can be applied.

Further, in the above-mentioned embodiment, the LED1 mounted on the LED holder 21 is ± 4 at the uppermost stage.
The case where the emission light L1 can be emitted with a spread of [° / oct] and the emission light L1 can be emitted with a spread of ± 15 [° / oct] at the bottom is described. However, the present invention is not limited to this, and as the LED 1 attached to the LED holder 21, an LED which has another spread and can emit light may be applied.

Further, in the above embodiment, each LED is
1 by arranging them so as to be located on a plurality of stages of circles around the axis of the LED holder 21.
The case has been described in which the imaging optical axis K10 of the D camera 3 is arranged on a plurality of circles having different diameters, but the present invention is not limited to this, and the point is that each LED 1 is a CCD.
It suffices to hold it so that it is positioned on a plurality of circumferences having different diameters with the imaging optical axis K10 of the camera 3 as the axis.

[0039]

As described above, according to the present invention, the inspection object of the inspection device for inspecting the inspection object by imaging the surface of the inspection object by the predetermined image pickup means and inspecting the image information thus obtained. In a lighting device for illuminating an image pickup area of an image pickup means on a surface of an object, a holding means for holding a plurality of light emitting means and each light emitting means around the image pickup area of the image pickup means so that a firing optical axis faces the image pickup area. By providing and, it is possible to allow each light emitting means to efficiently illuminate the inside of the image pickup area of the image pickup means, and thus it is possible to realize an illumination device with high illumination efficiency.

Further, an image pickup area of the image pickup means on the surface of the inspection object of the inspection device for inspecting the inspection object on the basis of the image information obtained by picking up the surface of the inspection object by the predetermined image pickup means is illuminated. In the lighting device described above, a plurality of light emitting means and a holding means for holding each light emitting means in a stepwise shape around the image pickup area along the image pickup direction of the image pickup means are provided. Compared with the case where the inspection target is held in parallel with the surface of the inspection target, the light emitting means in the outer peripheral portion can be brought closer to the image pickup area of the image pickup means, and thus an illumination device with high illumination efficiency can be realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an overall configuration of a lighting device according to an embodiment.

FIG. 2 is a schematic diagram showing a relationship between a direction of an emission optical axis of each LED and spots formed in an image pickup area of a CCD camera.

FIG. 3 is a schematic diagram used for explaining a mounting state of an LED with respect to an LED holder.

FIG. 4 is a cross-sectional view showing a conventional lighting device.

FIG. 5 is a schematic diagram showing the relationship between the direction of the emission optical axis of each LED and the spots formed in the image pickup area of the CCD camera in the conventional lighting device.

[Explanation of symbols]

1 ... LED, 3 ... CCD camera, 4 ... Inspection board,
10 ... Spot, 20 ... Lighting device, 21 ... LED
Holder, 21B ... Inside surface, 23 ... Diffusion plate, K1 ...
Emission optical axis, K10 ... Imaging optical axis, AR ... Imaging area, L
1 ... Shooting light.

Claims (12)

[Claims] 1. An image pickup means on the surface of the inspection object of an inspection apparatus for inspecting the inspection object on the basis of image information obtained by imaging the surface of the inspection object by a predetermined image pickup means. In the illuminating device for illuminating the image pickup area, a plurality of light emitting means and holding means for holding each of the light emitting means around the image pickup area of the image pickup means so that the emission optical axis faces the image pickup area. A lighting device characterized by the above. 2. The holding means holds each of the light emitting means such that the emission optical axis of the light emitting means is oriented in a substantially half region of the imaging area on the front side of the light emitting means. The lighting device according to claim 1, wherein the lighting device is a lighting device. 3. The lighting device according to claim 1, wherein the light emitting means is a light emitting diode. 4. The diffusing means, which is disposed between the light emitting means and the surface of the object to be inspected, for diffusing the light emitted from each of the light emitting means, respectively. Lighting equipment. 5. The holding means holds each of the light emitting means so as to be positioned on a plurality of circumferences having different diameters with the imaging optical axis of the imaging means as an axis. The lighting device according to 1. 6. An image pickup means on the surface of the inspection object of an inspection device for inspecting the object to be inspected on the basis of image information obtained by imaging the surface of the object to be inspected by a predetermined image pickup means. In the illumination device for illuminating the image pickup area, a plurality of light emitting means and holding means for holding each of the light emitting means in a step-like shape which is opened around the image pickup area along the image pickup direction of the image pickup means. Lighting device. 7. The holding means is a rigid body having an inner side surface inclined from the inner peripheral portion toward the outer peripheral portion, and each of the light emitting means is attached to the inner side surface of the holding means. The lighting device according to claim 6. 8. Each of the light emitting means is attached to the holding means such that the light emitting point is embedded in the inner side surface of the holding means to the extent that the light emitting point is at substantially the same height position as the inner side surface. The lighting device according to claim 7, wherein the lighting device is a lighting device. 9. The lighting device according to claim 6, wherein the light emitting means is a light emitting diode. 10. The light emitting device according to claim 6, further comprising a diffusing device which is disposed between the light emitting device and the surface of the inspection object and which diffuses light emitted from each of the light emitting devices. Lighting equipment. 11. Each of the holding means includes each of the light emitting means,
The lighting device according to claim 6, wherein the lighting device is held so as to be positioned on a plurality of circumferences having different diameters around the imaging optical axis of the imaging means. 12. The illumination device according to claim 6, wherein the holding means holds each of the light emitting means so that the emission optical axis thereof faces the image pickup area of the image pickup means.