JP2006051425A - Light irradiation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily miniatuarizable light irradiation device capable of accurately controlling light quantity to be irradiated on an irradiation object. <P>SOLUTION: This device is provided with a UV sensor 21 detecting light quantity of ultraviolet ray emitted from an LED 15, disposed in the vicinity of the LED 15 together with a temperature sensor 20 detecting the temperature of the LED 15. A control part 3 corrects a detected light quantity value detected by the UV sensor 21, using a detected temperature value detected by the temperature sensor 20, and feedback-controls a power supply to the LED 15 so that the corrected detected light quantity value converges to a light quantity value set by a user. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light irradiation apparatus that irradiates light such as ultraviolet rays with a light amount set for an irradiation target.

For example, a light irradiation device used in an industrial field, such as an ultraviolet irradiation device for irradiating and curing an irradiated portion such as an ultraviolet curable resin or an adhesive, particularly for an industrial subject It is important to stably irradiate a necessary amount of light. Therefore, in this type of light irradiation apparatus, for example, there is a technique disclosed in Patent Document 1 as a technique for controlling the amount of light applied to the irradiation target. In this technology, a part of the irradiation light emitted from the emission port is branched by a branching fiber, and the light amount of the branch light is detected by a UV sensor to estimate the light amount of the irradiation light, and the light is emitted according to the estimated light amount. The amount of light is adjusted by opening and closing the shutter of the mouth.
JP 2001-141899 A

  However, since the technique disclosed in Patent Document 1 described above has a complicated structure that requires a branching fiber or the like, it is particularly difficult to apply to a light irradiation apparatus that requires a reduction in size of the head portion. It is.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light irradiation apparatus that can accurately control the amount of light irradiated to an irradiation target and that can easily reduce the size of a head unit. To do.

  The present invention is based on the light amount detection means for detecting the light amount of light emitted from the light source in the vicinity of the light source, the temperature detection means for detecting the temperature of the light source, and the temperature detection value detected by the temperature detection means, A correction unit that corrects a light amount detection value detected by the light amount detection unit, and a light source control unit that controls power supplied to the light source so that the corrected light amount detection value converges to a set value. And

  According to the light irradiation apparatus of the present invention, it is possible to easily reduce the size by accurately controlling the amount of light irradiated to the irradiation target.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of an ultraviolet irradiation device, FIG. 2 is a cross-sectional view of the main part of the head, FIG. 3 is a flowchart of an LED control routine, and FIG. FIG. 5 is a main part sectional view showing a modification of the head part.

  In FIG. 1, the code | symbol 1 shows the ultraviolet irradiation device as an example of a light irradiation device. The ultraviolet irradiation device 1 is a device that spot-irradiates ultraviolet rays to an irradiation target. For example, a head unit 2 including a chip-type ultraviolet light emitting diode (UV-LED: hereinafter simply referred to as LED) 15 as a light source, And a control unit 3 that controls lighting of the LED 10 of the head unit 2.

  As shown in FIG. 2, the head portion 2 has a substantially cylindrical base 10 in which a male screw portion 10a is engraved on the outer peripheral surface on the distal end side, and a female screw portion 11a that is screwed into the male screw portion 10a. And a substantially cylindrical lens barrel 11 engraved on the inner peripheral surface on the side.

  An aluminum substrate 17 connected to the control unit 3 via the signal line 16 is fixed to the tip surface of the base 10, and the LED 15 is electrically connected to the aluminum substrate 17. The LED 15 is provided with a holder 18 having a substantially ring shape, and the base of the holder 18 is fixed to the aluminum substrate 17 with an adhesive or the like. The holder 18 is for positioning and fixing the LED 15 on the aluminum substrate 17 by being fixed to the aluminum substrate 17. At this time, the holder 18 holds the lens 19 between the LED 15.

  Further, in the vicinity of the LED 15, on the aluminum substrate 17, there are a temperature sensor 20 as temperature detecting means for detecting the temperature of the LED 15 and a UV sensor 21 as light quantity detecting means for detecting the amount of ultraviolet light emitted from the LED 15. Electrically connected.

  In this embodiment, the temperature sensor 20 is, for example, a chip thermistor type temperature sensor, and this temperature sensor 20 is fixed to the aluminum substrate 17 in a gap formed between the holder 18 and the aluminum substrate 17, The LED 15 is thermally connected via the silicon paste 22 filled in the gap.

  The UV sensor 21 is, for example, a photo IC diode that detects the amount of visible light emitted from the LED 15 in proportion to the emission of ultraviolet rays as a current value. The UV sensor 21 is attached to the holder 18 along the optical axis O. It is fixed to the aluminum substrate 17 in the formed notch 18a. Specifically, the UV sensor 21 indirectly detects the amount of ultraviolet light by detecting the amount of visible light emitted from the LED 15 and specularly reflected by a condenser lens 25 (described later).

  The lens barrel 11 has an inward flange 11b on the distal end side of the female screw portion 11a. The inward flange 11b is for holding a condensing lens 25 that condenses the ultraviolet rays emitted from the LED 15 into a predetermined light flux. Specifically, the inward flange 11b is a ring that is fitted to the inner periphery of the distal end portion of the lens barrel 11. A condensing lens 25 is sandwiched between the spacer 26. And the condensing lens 25 hold | maintained in this way in the lens-barrel 11 is the irradiation diameter of the ultraviolet-ray with respect to an irradiation object according to the distance from LED15 which changes with the screwing amount of the external thread part 10a and the internal thread part 11a. Is to change.

  As shown in FIG. 1, the control unit 3 includes a known microcomputer (microcomputer) 30 configured around a CPU (not shown). The microcomputer 30 includes a numeric keypad 31 for setting the amount of ultraviolet light emitted from the LED 15 by a user input, a display 32 for displaying various setting values, an alarm buzzer 33, and the like corresponding interfaces ( I / F) 34, 35, and 36, respectively.

  Further, the temperature sensor 20 and the UV sensor 21 are connected to the microcomputer 30 via the A / D converter 37, and an LED driver 39 that controls the power supplied from the power source 38 to the LED 15 is also connected to the D / A converter 40. Connected through.

  Then, the microcomputer 30 feedback-controls the power supplied from the power source 38 to the LED 15 through the LED driver 39 so that the UV light amount detection value detected by the UV sensor 21 converges to the light amount setting value. By the way, a dark current is generated in the UV sensor 21 of the present embodiment configured by a photo IC diode or the like, and this dark current increases exponentially as the ambient temperature rises, for example, as shown in FIG. . For this reason, even if the amount of ultraviolet light emitted from the LED 15 is the same, if the ambient temperature of the UV sensor 21 is different, the light amount detection value (current value) detected by the UV sensor 21 is different. Become. In particular, in the configuration of the present embodiment in which the UV sensor 21 is disposed in the vicinity of the LED 15, the light amount detection value is likely to be thermally influenced by the LED 15. Therefore, the microcomputer 30 corrects the light amount detection value in accordance with the LED temperature detected by the temperature sensor 20, and feedback-controls the power supplied to the LED 15 using the corrected light amount detection value. The microcomputer 30 stores, for example, a temperature correction value map for the light detection value set in advance through experiments, simulations, and the like. The microcomputer 30 uses this map to perform temperature correction for the light quantity detection value. Do. Further, the microcomputer 30 turns off the power supply from the power source 38 to the LED 15 when the temperature of the LED 15 exceeds a preset allowable value in order to prevent damage or the like due to overheating of the LED 15. That is, the microcomputer 30 functions as a correction unit and a light source control unit.

  Next, the LED control executed by the microcomputer 30 will be described with reference to the flowchart of the LED control routine shown in FIG. This routine is repeatedly executed every set time. When the routine starts, the microcomputer 30 first reads the detection values of the temperature sensor 20 and the UV sensor 21 in step S101.

  In subsequent step S102, the microcomputer 30 checks whether or not the temperature detection value of the LED 15 by the temperature sensor 20 is equal to or lower than the allowable temperature. If it is determined in step S102 that the detected temperature value of the LED 15 exceeds the allowable temperature, the microcomputer 30 proceeds to step S108, and the LED driver 39 is informed to the LED 15 in order to prevent the LED 15 from overheating. After instructing power-off, and further outputting an alarm through the buzzer 33, the routine is exited.

  On the other hand, if it is determined in step S102 that the temperature detection value of the LED 15 is equal to or lower than the allowable temperature, the microcomputer 30 proceeds to step S103. Then, the microcomputer 30 uses the temperature detection value of the LED 15 to set a correction value for the light amount detection value with reference to a preset map or the like, and performs temperature correction on the light amount detection value in the subsequent step S104.

  In step S105 from step 104, the microcomputer 30 checks whether or not the corrected light amount detection value is higher than the user set value.

  If it is determined in step S105 that the corrected light amount detection value is higher than the user set value, the microcomputer 30 proceeds to step S106 and performs a reduction correction of the supply current to the LED 15 on the LED driver 39. After giving instructions, exit the routine.

  On the other hand, if it is determined in step S105 that the corrected light amount detection value is lower than the user set value, the microcomputer 30 proceeds to step S107 and performs an increase correction of the supply current to the LED 15 on the LED driver 39. After giving instructions, exit the routine.

  According to such a configuration, the light amount detection value detected by the UV sensor 21 is corrected by the temperature detection value detected by the temperature sensor 20, and the power supplied to the LED 15 is feedback-controlled using the corrected light amount detection value. Therefore, even when the UV sensor 21 is disposed in the vicinity of the LED 15, the amount of ultraviolet light applied to the irradiation target can be accurately controlled, and the head unit 2 can be easily downsized. Can do.

  That is, by arranging the UV sensor 21 in the vicinity of the LED 15, it is possible to detect the amount of ultraviolet light emitted from the LED 15 with a simple configuration without using a complicated configuration such as a branching fiber. Since the UV sensor 21 can be provided on the same substrate (aluminum substrate 17), the head portion 2 can be reduced in size. At the same time, the thermal effect on the light quantity detection value caused by the UV sensor 21 being arranged in the vicinity of the LED 15 is corrected by the temperature detection value of the LED 15 detected by the temperature sensor 20, thereby accurately detecting the light quantity. A value can be obtained, and the amount of ultraviolet light can be accurately controlled using this light amount detection value.

  In this case, in particular, the temperature sensor 20 can also be used as a temperature sensor provided in the head unit 2 for the purpose of controlling overheating of the LED 15, thereby suppressing an increase in the number of parts, and the configuration of the head unit 2 can be further improved. It can be simplified.

  By the way, in the configuration for detecting the amount of ultraviolet light based on the reflected light from the condenser lens 25, the amount of reflected light reaching the UV sensor 21 changes as the distance from the condenser lens 25 to the UV sensor 21 changes. There is a case. Therefore, in addition to the temperature correction described above, correction based on the distance from the condenser lens 25 to the UV sensor 21 is performed on the light amount detection value detected by the UV sensor 21 to perform more precise LED control. Is possible.

  In this case, for detecting the distance from the condenser lens 25 to the UV sensor 21, for example, as shown in FIG. 5, a potentiometer 45 for detecting the relative rotation amount of the base 10 and the lens barrel 11 is provided in the head unit 2. This can be easily realized. That is, as shown in the figure, for example, the main body 45a of the potentiometer 45 is accommodated and held in the space 10b formed in the base 10, and the shaft portion 45b extending from the main body 45a faces the inside of the lens barrel 11, so that the shaft portion 45b By bringing the rubber ring 45c fixed at the tip into contact with the inner periphery of the lens barrel 11, the relative rotation amount between the base 10 and the lens barrel 11 can be detected. Then, the microcomputer 30 converts the relative rotation amount detected by the potentiometer 45 into a distance from the condenser lens 25 to the UV sensor 21, and based on the converted distance, refers to a preset map or the like to determine the correction amount. By obtaining this, the light amount detection value can be corrected.

Schematic diagram of ultraviolet irradiation equipment Cross section of the main part of the head LED control routine flowchart Chart showing temperature characteristics of dark current generated by UV sensor Cross-sectional view of the main part showing a modification of the head part

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ultraviolet irradiation apparatus (light irradiation apparatus), 15 ... Ultraviolet light emitting diode (light source), 20 ... Temperature sensor (temperature detection means), 21 ... UV sensor 21 (light quantity detection means), 30 ... Microcomputer (correction means, light source) Control means)
Agent Patent Attorney Susumu Ito

Claims (2)

A light amount detecting means for detecting the amount of light emitted from the light source in the vicinity of the light source;
Temperature detecting means for detecting the temperature of the light source;
Correction means for correcting the light quantity detection value detected by the light quantity detection means based on the temperature detection value detected by the temperature detection means;
A light irradiation apparatus comprising: a light source control unit configured to control power supplied to the light source so that the corrected light amount detection value converges to a set value.   2. The light irradiation apparatus according to claim 1, wherein the light source control unit turns off power supply to the light source when a temperature detection value detected by the temperature detection unit becomes equal to or higher than a set temperature.

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