JP2006073767A - Led lighting device and lighting control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting device which is capable of optionally changing its colors and irradiation angle, and to provide a lighting control unit using the same. <P>SOLUTION: The LED lighting device 10 is equipped with many LEDs which has various colors and uniformly arranged around a center opening, and a light diffusion resin board is provided in front of each of the LEDs. An LED driving unit 21 drives the LEDs of various colors independently. As the light of a desired color radiates uniformly at a wide angle, a specimen can be irradiated with light at an optional angle responding to a distance between the specimen itself and the LED. The LED lighting device 10 is successively changed in position and color by a controller 23 so as to detect a contrast between two points specified in an image picture, whereby a lighting position (lighting angle) and a lighting color optimal for the specimen can be automatically detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an LED (light emitting diode) illumination device and an illumination control device using the LED illumination device, and more particularly to an LED illumination device suitable for product inspection and the like and an illumination control device using the LED illumination device. Is.

  Conventionally, when a product image is captured by a camera and a product scratch or printed character is identified, it is known that the contrast between the scratch or the character and the background changes greatly depending on the illumination light irradiation angle. . Thus, various lighting devices for product inspection using LEDs have been proposed.

The following Patent Document 1 describes an LED illuminator previously filed by the present inventor. In this LED illuminator, LED elements are arranged inside a half-doughnut-shaped light diffusing resin plate to emit light, so that light along the shape of the light diffusing resin plate is externally reflected by irregular reflection in the light diffusing resin plate. Irradiated uniformly over a wide area. And the irradiation angle of the light to a sample can be changed by changing the distance of this LED illuminator and a sample.
Utility model registration No. 3085058

  In the above-described conventional illumination device, since a single color LED is used, it is necessary to replace the illumination device in order to change the illumination color. In addition, in the product inspection apparatus using this illumination device, the distance between the illumination device and the sample is manually adjusted while the operator looks at the monitor, so the optimum illumination position and illumination color are determined or reproduced. In order to do so, there is a problem that skill is necessary, and it takes time and it is unclear whether the adjusted point is a true optimum point or not. The present invention aims to solve the above-described problems.

The LED lighting device according to the present invention includes an LED light emitting unit disposed around a central opening portion, each of which includes a plurality of LED elements that emit light of different colors, and LED elements of the respective colors of the LED light emitting unit. The main features include wiring means that can be driven completely independently and light diffusing means disposed at least on the front surface of the LED light emitting means.
In the LED lighting device described above, the light diffusing unit may be a half donut shape having an overall shape cut by a plane perpendicular to the central axis.

  Further, in the above LED lighting device, each LED element of the LED light emitting means is repeatedly arranged in the same color arrangement pattern on a plurality of concentric circles on the disk-shaped substrate, and the color arrangement pattern in the adjacent concentric circles is colored. It may be shifted by half the repeat center angle of the array pattern. Alternatively, in the LED lighting device described above, the LED elements of the LED light emitting means are repeatedly arranged in the same color arrangement pattern on a plurality of squares or rectangles of different sizes on a square or rectangular substrate, and adjacent to each other. The color arrangement pattern on the square or rectangle may be shifted by half the repetition interval of the color arrangement pattern.

  In the LED lighting device described above, the LED elements that emit light of different colors may be LED elements that emit red, green, blue, and white light. Furthermore, in the LED lighting device described above, the substrate may be supported by a metal base.

  The illumination control device of the present invention includes the above-described LED illumination device, drive means for driving the LED illumination device, moving means for changing the distance between the LED illumination device and the sample, and a central opening of the LED illumination device. Camera means for photographing the sample through the part, monitor means for displaying the image data output from the camera means, and image data output from the camera means are captured, and the contrast between two desired points of the image is The main feature is that the driving means and the control means for controlling the moving means are provided so as to be maximized.

  Since the LED illumination device of the present invention uniformly emits light of a desired color at a wide range of angles due to the above-described features, the irradiated light is at a distance between the LED illumination device and the sample that is the irradiation object. There is an effect that irradiation at an arbitrary angle can be performed. In addition, since an optimal emission color can be selected for the sample, there is an effect that it is possible to cope with various sample inspections with a single LED illumination device.

  In addition, the illumination control device of the present invention can automatically detect the optimal illumination position (irradiation angle) and illumination color for the sample by the features as described above, and the effect of improving inspection efficiency and accuracy. There is. In addition, since the controller stores information on the optimal illumination position (irradiation angle) and illumination color for the sample, there is an effect that the same illumination state can be easily reproduced.

  Embodiments will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a hardware configuration of an illumination control device using the LED illumination device of the present invention. The illumination device 10 of the present invention is fixed to a support device 16, and the support device 16 is fitted to a support bar 14 fixed to the base 13 and is configured to be movable up and down by a stepping motor 17. ing. The illuminating device 10 has a donut shape having an opening at the center, and a plurality of light emitting LED's are disposed therein.

  The camera 12 images the sample 11 from the central opening of the illumination device 10 of the present invention, and outputs image data to the monitor 20 and the controller 23 by a video signal or the like. The camera 12 may be a video camera using a CCD image sensor, for example, and may be monochrome, but a color camera is preferred. Further, it may be sensitive to infrared rays or ultraviolet rays. The camera 12 is configured such that the height can be manually adjusted by a camera support device 15.

  Although the details will be described later, the LED driving device 21 drives the LEDs at a constant current independently for each emission color of the lighting device 10 under the control of the controller 23 or manual setting by the operator. The motor driving device 22 rotates the stepping motor 17 by a predetermined angle under the control of the controller 23 or manual setting by the operator.

  The controller 23 is realized, for example, by creating and installing a program for executing processing to be described later on a known personal computer equipped with a monitor, a keyboard, a mouse and the like. Note that image capture can be performed by mounting a known video capture interface card. If the camera image is displayed on the monitor device provided in the controller 23, the dedicated monitor 20 is not necessary.

  FIG. 2 is an explanatory view showing respective sample image examples when illumination light is irradiated from different angles using the illumination device of the present invention. FIG. 2A shows an example of a sample photographed image when the distance between the illumination device 10 and the sample 11 is 120 millimeters, for example. In this case, the irradiation angle to the sample is about 80 degrees. The entire surface of the central part of the sample is photographed brightly.

  FIG. 2B shows an example of a sample photographed image when the distance between the illumination device 10 and the sample 11 is 40 millimeters, for example. In this case, the irradiation angle is about 50 degrees. The circular part around the sample is photographed brightly. FIG. 2 (c) shows an example of a sample photographed image when the distance between the illumination device 10 and the sample 11 is set to 5 millimeters, for example. In this case, the irradiation angle is about 10 degrees. The hexagonal area around the sample is brightly photographed.

  In this way, when identifying scratches on products, printed characters, etc., the contrast between the scratches and characters and the background varies greatly depending on the illumination light irradiation angle, in order to improve the accuracy of product inspection, for example, It is necessary to perform illumination that maximizes the contrast of the area to be identified.

  FIG. 3 is a plan view and a cross-sectional view showing the configuration of the illumination device 10 of the present invention. FIG. 4 is an enlarged cross-sectional view showing the configuration of the illumination device 10 of the present invention. The lighting device 10 includes a printed wiring board 30 on which a large number of LEDs 31 are mounted, a light diffusion resin plate 34, a bracket (base) 32, and an insulating sheet 33. The printed wiring board 30 has a disk shape (ring shape) with an opening in the center, a large number of surface-mounted LEDs 31 are mounted on the surface, and lead wires for each color (not shown) are connected to the back surface. Yes.

  FIG. 5 is a plan view showing the mounting arrangement of the LEDs 31 on the printed wiring board 30. FIG. 5A shows the entire printed wiring board 30, and FIG. 5B is an enlarged view of a part of the printed wiring board 30. In FIG. 5B, the white LED 30 indicates an R (red) LED, and hatched hatching indicates G (green) and black indicates a B (blue) LED.

  Each LED 30 is arranged on five concentric circles by repeating a color arrangement pattern in the order of RGB, and the number and arrangement order of the LEDs arranged in each circle are the same. However, the LED arrangement of the first, third, and fifth circles from the inside is the same, that is, LEDs of the same color are arranged at the same angular position, but the LED arrangement of the second and fourth circles from the inside is 1. The LED arrangement of the third, third and fifth circles is deviated by half the center angle repeatedly. That is, the arrangement in adjacent circles is deviated by half of the center angle repeatedly. By adopting such an arrangement, substantially uniform irradiation light can be obtained in any emission color. The color arrangement may be RBG.

  The LEDs 30 are arranged at equal intervals on the circle, and the LEDs in adjacent circles are arranged so as to be shifted from each other by half of the LED arrangement interval. With such an arrangement, high-density mounting is possible. Note that a bullet-type LED with a condensing lens may be used as the LED 30, but a chip type without a condensing lens is more preferable because the irradiation angle is wide.

  The number of circles in which the LEDs 30 are arranged is an arbitrary positive number of 2 or more. Further, the number N of LEDs 30 arranged on one circle is a positive multiple of n, where n is the number of emitted colors. For example, if n is 3 (RGB), N may be 36. Further, W (white) may be added to RGB.

  An embodiment in which the LED lighting device 10 has a rectangular, square, or linear shape is also conceivable, but in this case as well, it may be arranged in the same arrangement pattern. For example, in the case of a square, the RGB LEDs 30 are repeatedly arranged in the same arrangement pattern on a plurality of squares of different sizes on a square substrate, and the arrangement pattern on the adjacent square is the repetition interval of the arrangement pattern. Try to be half off. In the case of a rectangle or a straight line, the arrangement of one side in the case of a square may be the same.

  The printed wiring board 30 is fixed to the bracket 32 with a screw or an adhesive (not shown) with an insulating sheet 33 interposed therebetween. The bracket 32 is a base for fixing the LED lighting device 10, and is fixed to the support device 16 with a screw, for example, by providing a screwed hole. The bracket 32 is made of a metal such as aluminum in order to have a heat dissipation effect. In order to enhance the heat dissipation effect to the bracket 32, silicon grease or the like may be filled in the gaps between the printed wiring board 30, the insulating sheet 33, and the bracket 32. Further, the entire interior of the LED lighting device 10 may be filled with silicon grease or resin.

  The light diffusing resin plate 34, which is a light diffusing means, is formed by cutting or cutting a resin plate made of a material that diffuses light such as milky white into a semi-doughnut shape in which the entire shape is cut by a plane perpendicular to the central axis. It is. In addition, the cross-sectional shape of the light-diffusion resin board 34 can be considered other than a semicircle. FIG. 7 is a cross-sectional view showing the configuration of another embodiment of the LED lighting device 10 of the present invention. FIG. 7A shows a cross-sectional shape of the light diffusing resin plate 34 in which a circle is divided into four equal parts. In this case, the cylindrical inner surface of the outer peripheral portion of the light diffusion resin plate 34 may be a mirror surface that reflects light. In addition, it is also possible to adopt a conical side surface shape in which the circumferential portion of FIG. 7A is a straight line and the cross section is a right triangle.

  FIG. 7B shows an embodiment for irradiating illumination light from various angles instead of a single irradiation angle. In this embodiment, the LED illumination device 10 is mounted in the opposite direction to that of FIG. 1, and the inner surface is a mirror surface that reflects light entirely on the opposite side of the sample of the LED illumination device 10, and an opening is provided on one end surface. At the other end, an open cylindrical reflection cover 51 is mounted. With such a configuration, illumination light can be irradiated from various angles.

  FIG. 6 is a circuit diagram showing circuits of the lighting device 10 and the LED driving device 21 of the present invention. In the lighting device 10, the LED 31 is formed by connecting a series circuit in which, for example, three LEDs 31 having the same emission color are connected in series, in parallel. The number of LEDs connected in series is arbitrary. Moreover, in order to make the brightness | luminance of each LED uniform, you may put resistance further in series in a series circuit.

  The LED driving device 21 sets the three variable constant current power supply circuits 40, 41, and 42 to desired current values based on the control signals from the three variable constant current power supply circuits 40, 41, 42 and the controller 23, respectively. It comprises a control circuit 43 for controlling.

  It should be noted that the LED drive current of each color of the lighting device 10 and the three variable constant current power supply circuits 40, 41, 42 in the LED drive device 21 so that the LED drive current of each color does not affect the LEDs of other colors. The lead wires that connect them are completely independent of each other.

  FIG. 8 is a flowchart showing the contents of the contrast scan process in the controller 23. When the controller 23 is activated, in S 10, the controller 23 initializes various parameters and controls the motor driving device 22 to move the illumination device 10 to an initial height. Take a picture and capture the image for specifying the position.

  In S11, the position designation image captured by the camera 12 is displayed on the monitor of the controller 23, and the operator is requested to designate two positions to be distinguished. Here, the operator uses a mouse or the like to specify the positions of two points to be distinguished, for example, a character portion and a background portion. The controller 23 stores the position coordinates of the designated two points.

  In S12, the illumination color designation information is initialized. The illumination color designation information is, for example, information that designates at which luminance each color of RGB is emitted. For example, one bit is assigned to each of RGB to control on (luminance 100%) / off (luminance 0%) of each color. It may be a thing. Further, 2 bits may be assigned to each color, and the luminance may be controlled in four steps of 100%, 67%, 33%, and 0%, or more bits may be assigned.

  In S13, the LED driving device 21 is controlled to turn on the lighting device 10 with the designated color of the illumination color designation information. In S14, image data photographed by the camera 12 is captured. In S15, the lighting device 10 is turned off by controlling the LED driving device 21.

  In S16, the luminance data of the two points designated in S10 of the captured image are extracted, and the difference (contrast) is calculated. In S17, it is determined whether or not the current difference is the highest by comparing the difference data with the highest value of the past difference. If the determination result is negative, the process proceeds to S19. Shifts to S18.

  In S18, the current height information and illumination color designation information of the illumination device 10 are stored in a predetermined area. In S19, it is determined whether or not the contrast measurement processing has been completed for all the colors. If the determination result is negative, the process proceeds to S20, but if the determination is affirmative, the process proceeds to S21. In S20, the illumination color designation information is changed to information corresponding to an illumination color that has not yet undergone contrast measurement processing, and the process returns to S13.

  In S21, it is determined whether or not the height information of the illuminating device 10 is a predetermined final height at which the contrast scanning process is finished. If the determination result is negative, the process proceeds to S22, but if the determination is affirmative, the process proceeds to S23. Transition. In S22, the motor driving device 22 is controlled to drive the motor 17, and the height of the lighting device 10 is changed. In addition, the change of the irradiation angle with respect to a movement distance becomes small, so that the distance of the illuminating device 10 and the sample 11 increases. Therefore, the movement distance may be increased as the distance between the illumination device 10 and the sample 11 increases so that the change in the irradiation angle becomes constant.

  In S23, the height information of the illumination device 10 and the illumination color designation information stored in the predetermined area and having the highest contrast are displayed on the monitor of the controller 23. Further, based on the height information and illumination color designation information of the illumination device 10 with the highest contrast, the LED drive device 21 and the motor drive device 22 are controlled to reproduce the illumination state with the highest contrast. With the configuration and processing as described above, the illumination state with the highest contrast can be automatically detected and reproduced.

  Although the embodiments have been described above, the following modifications can be considered for the apparatus of the present invention. In the embodiment, an example is disclosed in which an illumination state in which the contrast between two points is maximized is detected. However, in some cases, it may be desired to cancel unnecessary background or noise. In this case, an illumination state in which the contrast between the two points is the lowest (same luminance) may be determined.

  In the embodiment, an example in which the illumination angle is changed by moving the illumination device 10 is disclosed. However, for example, a plurality of illumination devices are arranged at different distances, and the illumination angle is changed by switching the illumination device driven by a switch. Can be changed. In this case, the diameter of the illumination device closer to the sample may be increased. Furthermore, by arranging LEDs of multiple colors on the inner surface of any one of cylindrical, conical, quadrangular, and rectangular parallelepiped, and selecting the LED to be driven by a switch, the color and illumination angle of the illumination light can be changed without moving parts. Is possible. Further, for example, by causing all LEDs to emit light, illumination light can be irradiated from various angles.

  In the embodiment, an example in which LEDs of three colors of RGB are used is disclosed, but a white (W) LED may be added. In this case, the arrangement may be RGBW, or an arrangement pattern of RWGWWB by increasing white. Furthermore, an infrared LED or an ultraviolet LED may be added depending on the application. In this case, a camera having sensitivity in a necessary wavelength region is used.

  In the case of automatically performing contrast adjustment, an example in which the difference in luminance is maximized has been disclosed. However, since a luminance of each RGB can be obtained with a color camera, the contrast for each RGB is calculated and each color is calculated. You may make it detect the one with the largest contrast difference.

It is a block diagram which shows the hardware constitutions of the illumination control apparatus which uses the LED lighting apparatus of this invention. It is explanatory drawing which shows each sample image example at the time of irradiating illumination light from a different angle using the illuminating device of this invention. It is the top view and sectional drawing which show the structure of the illuminating device 10 of this invention. It is an expanded sectional view which shows the structure of the illuminating device 10 of this invention. 2 is a plan view showing a mounting arrangement of LEDs 31 on a printed wiring board 30. FIG. It is a circuit diagram which shows the circuit of the illuminating device 10 and the LED drive device 21 of this invention. It is sectional drawing which shows the structure of the other Example of the LED lighting apparatus 10 of this invention. 5 is a flowchart showing the contents of contrast scan processing in a controller 23.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Illuminating device 11 Sample 12 Camera 13 Base 14 Support rod 15 Camera support device 16 Support device 17 Stepping motor 20 Monitor 21 LED drive device 22 Motor drive device 23 Controller

Claims (7)

LED light emitting means disposed around the central opening portion and provided with a plurality of LED elements each emitting light of different colors;
Wiring means capable of driving each LED element of each color of the LED light emitting means completely independently;
An LED illuminating device comprising: a light diffusing unit disposed at least on a front surface of the LED light emitting unit.   2. The LED lighting device according to claim 1, wherein the light diffusing unit has a half donut shape in which an overall shape is a donut cut along a plane perpendicular to a central axis.   Each LED element of the LED light emitting means is repeatedly arranged in the same color arrangement pattern on a plurality of concentric circles on a disk-shaped substrate, and the color arrangement pattern in adjacent concentric circles is only half of the repetition center angle of the color arrangement pattern. The LED illumination device according to claim 2, wherein the LED illumination device is deviated.   The LED elements of the LED light emitting means are repeatedly arranged in the same color arrangement pattern on a plurality of squares or rectangles of different sizes on a square or rectangular substrate, and the color arrangement patterns on adjacent squares or rectangles are arranged. The LED illumination device according to claim 1, wherein the LED illumination device is deviated by half of a repetition interval of the color arrangement pattern.   The LED lighting device according to claim 3, wherein the LED elements that emit light of different colors are LED elements that emit red, green, blue, and white light.   The LED lighting device according to claim 3, wherein the substrate is supported by a metal base. LED lighting device according to any one of claims 1 to 6,
Driving means for driving the LED lighting device;
Moving means for changing the distance between the LED illumination device and the sample;
Camera means for photographing the sample through the central opening of the LED illumination device;
Monitor means for displaying image data output from the camera means;
Control means for taking in image data output from the camera means and controlling the driving means and the moving means so that a contrast between two desired points of the image is maximized. apparatus.

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