JP3565772B2 - Line light source device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a long line light source device for high-speed image processing that emits light with a stable light amount.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a light source having a stable light amount has been required as a light source used for optical inspection, various measures have been taken, and a surface light source device by the present applicant has been proposed as a light source for realizing a uniform illuminance distribution. This light source is provided with a lighting power supply for each of a plurality of fluorescent lamps arranged side by side, and adjusts the discharge current of each light source lamp to correct the variation in the light amount of the fluorescent lamp and reduce the illuminance decrease near the fluorescent lamp electrode portion. A supplementary light source fluorescent lamp is provided to make the entire light emitting surface have uniform illuminance.
[0003]
[Problems to be solved by the invention]
However, fluorescent lamps contain a small amount of mercury in order to emit light from the phosphor applied to the inner surface of the tube, and the luminous efficiency has a temperature characteristic in relation to the vapor pressure of mercury. Although it is good to use it in a receiving room or a constant temperature room, there is a problem that a desired light amount cannot be obtained depending on the use environment.
[0004]
In addition, a long fluorescent tube is required to secure the length of the illumination. However, it is difficult to obtain an illumination longer than 2 meters due to the limitation of the ability to produce the fluorescent tube.
[0005]
In order to always obtain a stable light source, it is necessary to feed back the output. For this purpose, a photo sensor outside the lamp and the intensity of the reflected light from the subject are received by a camera, etc., and the detection result is fed back. However, in the detection outside the lamp, it changed depending on the stain of the lamp cover and the situation of the subject, and a stable detection result was not obtained.
[0006]
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a long line light source device that emits light with a stable light amount regardless of the temperature of a use environment.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, a line light source device according to the present invention includes a light source unit including a plurality of fluorescent lamps, a rod lens that condenses the light of the fluorescent lamps in a line, and turns on the fluorescent lamps. It is characterized by having the following requirements having a lighting control device.
(A) In the fluorescent lamp, the vicinity of the electrode portion where the illuminance is reduced is overlapped with the vicinity of the central portion where the illuminance of the other fluorescent lamp is stable and alternately arranged at predetermined intervals, and the fluorescent lamp and the fluorescent lamp are alternately arranged. The same number of reflectors for reflecting the light of the fluorescent lamp to the rod lens are arranged corresponding to each of the fluorescent lamps.
(B) The reflectors are arranged such that the ends in the longitudinal direction are in contact with each other, and the abutting portion is located at an overlapping portion of the fluorescent lamp, and the light of the corresponding fluorescent lamp is selectively reflected by the rod lens. that you have been [0008]
The light source unit is provided with a temperature sensor for detecting an ambient temperature of the fluorescent lamp, a light amount sensor for detecting a light amount of the fluorescent lamp, and an air conditioner, and the lighting control device performs the above based on a detection result of the temperature sensor. It is preferable that the air conditioner is controlled to maintain the ambient temperature of the fluorescent lamp at a predetermined temperature, and that the discharge current is controlled based on the detection result of the light amount sensor to make the light amount of the fluorescent lamp a predetermined light amount.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a line light source device according to the present invention. The line light source device includes a light source unit A using a fluorescent lamp as a light source, a lighting control device B for controlling lighting of the fluorescent lamp, and an abnormality occurring in the light source unit A. In this case, the warning unit C notifies the user of the abnormality and outputs an abnormality signal.
[0010]
The light source section A includes a plurality of straight tube fluorescent lamps 2 (in the present invention, two fluorescent lamps 2a and 2b) disposed inside a housing 1 formed in a tubular shape having a substantially inverted trapezoidal cross section, and a fluorescent lamp 2 And the same number of reflectors 3 (two reflectors 3a and 3b in the present invention) and one rod lens 4. As shown in FIG. 2, the rod lens 4 is attached to the top plate 5 of the housing. A portion 4a of the peripheral surface is supported by the fixed support member 6 and is exposed from an opening 7 formed in the lower surface of the housing 1 in the longitudinal direction (see FIG. 4A). An air conditioner 9 is provided in an air conditioning room 8 projecting upward.
[0011]
In FIG. 1, reference numeral 10a denotes a screw hole formed on the upper surface of the housing. The screw hole 10a is for fixing the light source unit A to a support member (not shown), and the reference numeral 10b is a side cover. 1 shows a simple detachable latch (ni-latch) for fixing the fluorescent lamp 2. The fluorescent lamp 2 can be easily replaced by removing the side cover 1 a by taking the simple detachable latch 10 b.
[0012]
The fluorescent lamps 2a and 2b are constituted by aperture fluorescent lamps provided with a linear irradiation port (aperture portion) ap in the longitudinal direction, and are arranged parallel to the rod lens 4 and at a predetermined interval between the fluorescent lamps 2a and 2b. It is arranged so as to form a substantially isosceles triangle in side view having the rod lens 4 as an inverted vertex. In the fluorescent lamp 2, the vicinity a of the electrode portion where the illuminance decreases is overlapped with the vicinity b of the central portion where the illuminance of the other fluorescent lamps 2 is stable. They are arranged in parallel at predetermined intervals so as to be continuous (see FIG. 3B).
[0013]
Light amount sensors (photo sensors) 14a and 14b for detecting the illuminance of the fluorescent lamps 2a and 2b are located at positions away from the reflectors 3a and 3b so as to prevent disturbance light from entering and at the ends of the fluorescent lamps 2a and 2b. It is installed closer to the aperture portion ap closer to the center.
[0014]
The reflecting plates 3a and 3b are formed of mirrors and are disposed between the fluorescent lamps 2a and 2b, and the mirror surfaces can irradiate the rod lens 4 with light emitted from the aperture portions ap of the fluorescent lamps 2a and 2b. Are arranged as follows. As shown in FIG. 4A, the reflector 3a reflects the light of the fluorescent lamp 2a toward the rod lens 4 with a mirror surface, and the reflector 3b reflects the light of the fluorescent lamp 2b as shown in FIG. Are reflected so as to be reflected toward the rod lens 4 by a mirror surface. Further, as shown in FIG. 3B, the end portions of the reflector 3a and the reflector 3b are in contact with each other, and the contact portion c is disposed so as to be in the center of the overlapping portion d of the fluorescent lamps 2a and 2b. The light from the two fluorescent lamps is used as light from a single fluorescent lamp (pseudo fluorescent lamp) so that the light reflected by the reflectors 3a and 3b becomes one long light without interruption. The light can be applied to the rod lens 4. 4 (a) and 4 (b), reference numeral 18 denotes a holding plate for holding the long rod lens 4 in the housing so as not to bend, and reference numeral 20 denotes a heat insulating plate for preventing the rod lens 4 from being affected by an external temperature. Is shown.
[0015]
If a longer light source is required, the light source can be constituted by one rod lens, three or more fluorescent lamps 2 formed to the required length, and reflectors 3 equal in number to the fluorescent lamps 2. In the case of a short line light source, one light source may be configured by disposing one fluorescent lamp in parallel above one rod lens without providing a reflector.
[0016]
The air conditioner 9 includes a Peltier device 11 that generates and absorbs heat according to the direction of the applied current, and two fans 12 and 13 that are provided so as to sandwich the Peltier device 11 from both sides. A large number (16 in the present invention, 9a to 9p) are juxtaposed at predetermined intervals in the longitudinal direction on the upper air-conditioning room 8. The outer fan 12 is superposed and fixed on a heat sink 19 a attached to the upper surface of the Peltier element 11, blows out toward the outside of the housing 1 so as to cool the heat generated on the upper surface of the Peltier element 11, and Reference numeral 13 denotes a heat sink 19b mounted on the lower surface of the Peltier device 11 and fixed thereon by superimposition. The cooling heat or heat generated by the heat absorption of the lower surface of the Peltier device 11 is blown into the housing 1 through the opening 5a formed in the top plate 5. The temperature of the surroundings of the fluorescent lamp 2 is lowered or raised by changing the direction and magnitude of the current flowing through the Peltier element 11, thereby sending cold or warm air into the housing 1. This is to keep the temperature constant without being affected by the surrounding temperature. When the fan 12 or 13 stops, the air conditioner 9 can output a fan alarm signal indicating that the fan 12 or 13 has stopped.
[0017]
FIG. 5 shows a block diagram of the lighting control device B. The lighting control device B turns on the fluorescent lamp 2 and uses the photosensors 14a and 14b installed in close contact with the aperture portion of the fluorescent lamp 2 so as to emit the fluorescent light 2a. , 2b are respectively detected, and when the illuminance decreases, the illuminance lowering alarm circuits 21a, 21b output the illuminance warning signals s1, s2 via the insulating circuits 22a, 22b composed of photocouplers. As a result, a malfunction does not occur in the connected external device due to electric noise or fluctuation of the ground level.
[0018]
The illuminance lowering criteria for outputting the illuminance warning signals s1 and s2 can be set by the switches 15a and 15b (in the present invention, five steps of 10% to 50%). The polarity switching circuits 16a and 16b periodically change the polarity of the discharge current in order to eliminate the arc bias phenomenon. This polarity switching employs a semiconductor high-speed automatic switching circuit that switches in synchronization with a built-in oscillator that has little effect on emitted light.
[0019]
In the present invention, the polarity change cycle is set within 5 seconds, and the switching time is set within the afterglow time. As a result, it is possible to reduce the time change of the illuminance at the fluorescent lamp boundary.
[0020]
Further, the discharge currents of the fluorescent lamps 2a, 2b are monitored by the current detection resistors 17a, 17b, respectively. When it is detected that the fluorescent lamps 2a, 2b have gone out and the discharge current has stopped flowing, the extinguishing alarm circuits 24a, 24b are provided with a photo The extinguishing warning signals s3 and s4 are isolated and output via the insulating circuits 25a and 25b formed of couplers. As a result, a malfunction does not occur in the connected external device due to electric noise or fluctuation of the ground level.
[0021]
The illuminance warning signals s1 and s2 and the extinguishing warning signals s3 and s4 may be transmitted to a remote controller (for example, a personal computer or the like) 27 and may be subjected to appropriate processing (for example, stop of an inspection line, generation of an alarm, etc.).
[0022]
FIG. 6 is a block diagram of the air conditioner 9 and a control unit D for controlling the air conditioner. The control unit D is incorporated in a housing of the lighting control device B.
[0023]
The control unit D controls the operation of the air conditioner 9 based on the detection results of the temperature sensors 28 (28a, 28b) disposed in the housing 1. The output signals s9, s10 of the temperature sensors 28a, 28b are warnings. If the temperature is input to the control unit D via the unit C and the temperature inside the housing 1 is higher than the set temperature, a current flows in a direction in which the Peltier element 11 absorbs heat, and cool air is sent into the housing 1. If the temperature in the housing is lowered, and the temperature in the housing 1 is lower than the set temperature, the relays 29a to 29p are switched to flow a current in a direction in which the Peltier element 11 generates heat, and hot air is blown into the housing 1. The temperature inside the housing 1 is increased by feeding the heat so that the temperature inside the housing 1 is always constant without being affected by the ambient temperature or the heat generated by the fluorescent lamp. And it is controlled.
[0024]
As a result, a high light output is maintained by maintaining an optimum tube wall temperature (about 40 ° C.) with respect to the ambient temperature characteristics of the fluorescent lamp 2 (the relationship between the vapor pressure of enclosed mercury and the tube wall temperature). Obtainable. When any of the fans 12a to 12p or 13a to 13p stops, fan alarm signals s11 to s26 are output, and the fan alarm signals are input to the warning unit C.
[0025]
FIG. 7 shows a warning unit C. This warning unit C corresponds to a corresponding fan when a fan alarm signal s11 to s26 generated by stopping one of the fans 12a to 12p or 13a to 13p is input. The display lamps 23a to 23p are turned on and off, and a fan stop signal s27 notifying that the fan has stopped is output. The fan stop signal s27 may be transmitted to the above-described remote controller, and the remote controller may perform an appropriate process (for example, stop the inspection line, generate an alarm, and the like). In FIG. 7, reference numerals 26a to 26p denote one-shot multivibrators that blink one of the display lamps 23a to 23p in response to the input fan alarm signals s11 to s26.
[0026]
According to the above-described line light source device, a line light source having an arbitrary length can be produced by increasing or decreasing the number of fluorescent lamps. In addition, since the vicinity of the electrode portion of the fluorescent lamp is shielded by a reflector for another fluorescent lamp, and the light from the other fluorescent lamp is irradiated on the rod lens by the reflector, the two fluorescent lamps are simply arranged side by side. When the light is condensed by a lens, as shown in FIG. 8B, there is a region where no light is output in any way around the fluorescent lamp holding bracket, and a uniform illuminance distribution cannot be obtained in the width direction. However, by reflecting only the central portion of the fluorescent lamp near the electrode portion excluding the dark portion toward the rod lens with the reflector, the effective light emitting area of the fluorescent lamp can be made continuous. As shown, a long line light source that can obtain a stable illuminance distribution without dark portions in the width direction can be manufactured.
[0027]
If the temperature control is not performed, the temperature around the fluorescent lamp increases with time, and the luminous efficiency of the fluorescent lamp decreases accordingly. As shown by the dotted line in FIG. 9, the illuminance decreases in proportion to time. However, since the temperature around the fluorescent lamp is always kept constant over the entire width direction by the air conditioner, the luminous efficiency due to the temperature rise is reduced. As shown by the solid line in FIG. 9, it is possible to maintain a stable illuminance that is not affected by the temperature even when the time elapses, without causing a decrease.
[0028]
Further, when the polarity conversion cycle of the DC lighting power supply is set to 30 seconds, electrons are localized on the positive electrode with the lapse of time, so that the luminous efficiency in the width direction becomes non-uniform as shown by the dotted line in FIG. When the polarity is changed in a cycle of one second, the polarity is changed before the electrons are localized on the positive electrode. Therefore, as shown by the solid line in FIG. 10, non-uniformity of the illuminance does not occur. The repetition of the polarity conversion affects the life of the fluorescent tube. Therefore, the polarity conversion cycle is set to 0.5 seconds or more. If the polarity conversion cycle is less than 5 seconds as shown by the dotted line in FIG. Therefore, the polarity conversion cycle may be set within 5 seconds, and the polarity switching time may be set within the afterglow time.
[0029]
Then, since it is possible to output a warning signal such as a decrease in illuminance, turning off of a lamp, stopping of a fan, and the like, when used as a line light source of an automatic inspection device or the like, the remote controller can grasp the state of the line light source. Therefore, a trouble such as continuous operation of the inspection system with an abnormality in the line light source does not occur.
[0030]
By the way, as shown in FIG. 5, the binary 4-bit signals (0 to F) s5 and s6 from the remote controller are isolated and input to the D / A converters 36a and 36b via the insulating circuits 35a and 35b each formed of a photocoupler. The signal is converted into an analog signal, passes through a level adjustment circuit (not shown), becomes a reference voltage for the current control circuits 37a and 37b, and the current control circuits 37a and 37b output the light amount signals s7 and s8 detected by the photosensors 14a and 14b, respectively. The discharge current is controlled such that the light amount signals s7 and s8 match the reference voltage by comparing with the reference voltage. Therefore, the range from the upper limit to the lower limit of the light quantity variable range can be set in 16 steps using a 4-bit digital signal.
[0031]
In FIG. 5, reference numerals 38a and 38b denote volumes for variably adjusting the level of the reference voltage of the current control circuits 37a and 37b, and reference numerals 39a and 39b denote light source illuminance by a 4-bit illuminance setting signal from the remote controller 27. A changeover switch for selecting whether to set the value manually or manually using the volumes 38a and 38b is shown.
[0032]
【The invention's effect】
According to the present invention, a line light source device having an arbitrary length can be realized by increasing the number of fluorescent lamps. In addition, the fluorescent lamps are arranged continuously so that the vicinity of the electrode portion where the illuminance is reduced overlaps with the vicinity of the central portion where the illuminance of other fluorescent lamps is stable, and furthermore, the reflecting plate is continuous at the overlapping portion of the fluorescent lamps. As a result, it is possible to make a long light source with only the central part of a fluorescent lamp with stable illuminance connected, and to realize a light source with uniform brightness without uneven illuminance even with a long light source. it can.
[0033]
By providing the air conditioner, the temperature around the fluorescent lamp can be kept constant, so that a light source having a stable light quantity without being affected by the environmental temperature can be provided.
[0034]
In addition, since the light amount sensor is arranged and the discharge current is controlled so that the light amount is always constant, a light source with a more stable light amount can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the configuration of a line light source device according to the present invention. FIG. 2 is a perspective view illustrating the configuration of a light source unit. FIGS. 3 (a) and 3 (b) are side views of the light source unit and the inside of a housing. FIG. 4A and FIG. 4B are end views of a main part of an XX line and a main part of a YY line of FIG. 3A, illustrating a relationship between the arranged fluorescent lamps and a reflection plate. FIG. 5 is a block diagram of a lighting control device. FIG. 6 is a block diagram of an air conditioner. FIG. 7 is a block diagram of a warning unit. FIG. 8A and FIG. FIG. 9 is a graph showing the illuminance distribution in the full width direction of the line light source of FIG. 9; FIG. 9 is a graph illustrating the change in illuminance between when the line light source is provided with an air conditioner and when it is not provided; FIG. Graph showing relationship with illuminance [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Housing 2 Fluorescent lamp 3 Reflector 4 Rod lens 9 Air conditioner 14 Light intensity sensor 28 Temperature sensor A Light source B Lighting control device

Claims (2)

The light source unit includes a plurality of fluorescent lamps, a rod lens that condenses the light of the fluorescent lamps in a line, and a lighting control device that turns on the fluorescent lamps. Line light source device.
(A) In the fluorescent lamp, the vicinity of the electrode portion where the illuminance is reduced is overlapped with the vicinity of the central portion where the illuminance of the other fluorescent lamp is stable and alternately arranged at predetermined intervals, and the fluorescent lamp and the fluorescent lamp are alternately arranged. The same number of reflectors for reflecting the light of the fluorescent lamp to the rod lens are arranged corresponding to each of the fluorescent lamps.
(B) The reflectors are arranged such that the ends in the longitudinal direction are in contact with each other, and the abutting portion is located in an overlapping portion of the fluorescent lamp, and the light of the corresponding fluorescent lamp is selectively reflected by the rod lens. is being done The light source unit is provided with a temperature sensor for detecting an ambient temperature of the fluorescent lamp, a light amount sensor for detecting a light amount of the fluorescent lamp, and an air conditioner. The lighting control device controls the air conditioner based on a detection result of the temperature sensor. 2. The line light source according to claim 1, wherein the control unit controls the ambient temperature of the fluorescent lamp to a predetermined temperature, and controls a discharge current based on a detection result of the light amount sensor to make the light amount of the fluorescent lamp a predetermined light amount. apparatus.

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