JPH05312637A - Optical fiber illuminator - Google Patents

Abstract

PURPOSE:To realize an optical fiber illuminator employing a halogen lamp light source in which quantity of transmitted light of a monitor fiber is monitored by means of a light receiving unit, a feedback loop is established to the driving circuit for the halogen lamp, and the power thereof is controlled so that variation of the quantity of light is corrected thus sustaining the total flux at the time of initial lighting with power slightly lower than a rated power upto the end of life of the halogen lamp thereby sustaining high illuminance, high output, and high stability upto the end of life. CONSTITUTION:A monitor fiber 5 is branched from a fiber 4 projecting variation of the quantity of light radiated from a light source, i.e., a halogen lamp 1. Light outputted from the monitor fiber is introduced to a light receiving unit 3 which constantly monitors variation of the quantity of light radiated from the halogen lamp. A feedback loop is established to the driving circuit 2 for the halogen lamp in order to correct output from the halogen lamp depending on the variation of the quantity of light radiated from the halogen lamp thus keeping constant the quantity of light radiated from the end of projecting fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber illuminating device using a halogen lamp as a light source, which is used for illuminating an image processing / inspecting device and in the light receiving sensitivity inspection of a light receiver or the like.

[0002]

2. Description of the Related Art In recent years, image processing technology has advanced, and it is becoming widespread to take in an image of a work target as information by a TV camera, an optical sensor or the like, and perform control based on this image information. In such an image processing technique, a halogen lamp is used as a light source for illuminating a minute object such as an IC chip or a silicon wafer or a semiconductor element or an electronic component, and the transmitted light is transmitted through an optical fiber. Used.

In a lighting device using such a halogen lamp and an optical fiber, a constant voltage power source or a constant current power source has conventionally been used to light a halogen lamp as a light source. However, when performing image processing that relies on lighting,
Accurate image information cannot be obtained by causing a change in illuminance due to light amount attenuation due to deterioration of the halogen lamp over time.

Since the conventional method of lighting a halogen lamp with a constant voltage power source or a constant current power source is an optical fiber illuminating device which ignores the change in illuminance due to the change over time of the halogen lamp, an image processed according to the change in illuminance is displayed. Each time there is an error in the information, the output of the power supply that turns on the halogen lamp is manually adjusted, or CC
There is a drawback in that it is necessary to adjust the sensitivity adjustment and the iris of the camera on the input side of an image processing device such as a D camera to set appropriate image processing conditions.

In the image processing technology for selecting a good product and a defective product at a production site by using such an optical fiber illuminating device, it is necessary and expected that the illumination and the image processing device are regularly adjusted. There is a problem that production efficiency is not achieved.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned conventional drawbacks and problems, and is used for the inspection of the light receiving sensitivity of the illumination and the light receiver of the image processing inspection apparatus. It is an object of the present invention to provide an optical fiber lighting device using a halogen lamp as a light source, which has high brightness, high output and high stability.

[0007]

An optical fiber illuminator according to the present invention is provided with a monitor fiber branched from a light projecting fiber for projecting a change in the amount of light emitted from a halogen lamp as a light source. The light emitted from the halogen lamp is guided to the light receiver, and the light receiver constantly monitors the light amount change state of the light emitted from the halogen lamp, and feedback is applied to the driving circuit of the halogen lamp to emit the light from the halogen lamp. The output of the halogen lamp is corrected according to a change in the amount of light emitted from the light emitting fiber, and the amount of light emitted from the emitting end of the light projecting fiber is kept constant.

The light source used for such an optical fiber illuminating device is mainly a halogen lamp for a projector / optical equipment, which has a lighting voltage of 15V and a power consumption of 150W. In order to achieve high brightness, these halogen lamps have been devised so that the filament shape is made small and the impedance of the filament is made small so that a large amount of current is passed to increase the luminous efficiency.

Therefore, since the filament of the halogen lamp emits light at a high temperature close to the melting point of the filament material, it deteriorates quickly, and the luminous efficiency and the total luminous flux decrease as the lighting time elapses.

Therefore, in the present invention, the halogen lamp is lit at a power slightly lower than the rated power at the initial lighting, and within the range of the maximum input power that the halogen lamp can withstand,
The light receiver monitors a change in the amount of transmitted light of the monitor fiber, applies feedback to the driving circuit of the halogen lamp, and controls the power of the halogen lamp.
This is an attempt to correct the change in light quantity.

[0011]

As described above, according to the present invention, at the time of initial lighting, the halogen lamp is lit at a power slightly lower than the rated power, and within the maximum input power range of the halogen lamp,
The light receiver monitors the light amount of the transmitted light of the monitor fiber, feeds back the driving circuit of the halogen lamp, controls the electric power of the halogen lamp, and corrects the change in the light amount, whereby the halogen lamp is initially turned on. The total luminous flux is maintained until the end of the life of the halogen lamp.

[0012]

EXAMPLES Examples of the present invention will be described below.
The invention is not limited to this example. Example 1 FIG. 1 shows a first example of the optical fiber lighting device of the present invention.
It is explanatory drawing which shows the Example of. In FIG. 1, a first embodiment of this optical fiber illuminating device is a light projecting fiber 4 in which a plurality of optical fibers for guiding light emitted from a halogen lamp 1 are bundled, and light is emitted from a part of the light projecting fiber 4. The monitor fiber 5 is formed by branching one or more fibers, and the monitor fiber 5 guides part of the light emitted from the halogen lamp 1 and receives the light.

The voltage generated in the photodetector 3 is amplified by a preamplifier 6 and compared with a reference voltage output from a reference voltage setting device 8 which is initialized in advance by a comparator (comparator) 7 to drive the halogen lamp 1. By feeding back to the circuit 2 and keeping the amount of light emitted from the halogen lamp 1 constant, the amount of light emitted from the emission end of the light projecting fiber 4 is made constant.

The incident end of the light projecting fiber 4 and the incident end of the monitor fiber 5 are bound and fixed by a fiber binding ring 13. The emission end of the monitor fiber 5 is bound and fixed by a fiber binding ring 14. The emitting end of the light projecting fiber 4 is bound and fixed by a fiber binding ring 15.

[Second Embodiment] FIG. 2 is an explanatory view showing a second embodiment of the optical fiber illuminating device of the present invention. In the second embodiment shown in FIG. 2, a voltage detector 9 and a voltage abnormality indicator 10 are added to the first embodiment. The voltage output to the halogen lamp 1 is constantly detected to reach a preset upper limit voltage to be output to the halogen lamp 1 to determine whether or not the control range is exceeded.

That is, the output voltage from the light receiver 3 which has passed through the preamplifier 6 is detected by the voltage detector 9. This output voltage corresponds to the reference voltage of the reference voltage setting device 8 and the comparator 7
When the output voltage exceeds a predetermined range as a result of the comparison by the comparator 7, it is judged as abnormal and the abnormality is displayed on the voltage abnormality indicator 10.

[Embodiment 3] FIG. 3 shows a third embodiment of the optical fiber illuminating device of the present invention. In the third embodiment, a current detector 11 and a current abnormality indicator 12 are added to the above-described second embodiment. The current flowing through the halogen lamp 1 is detected by the current detector 11, and the current abnormality indicator 12 judges whether or not the limit current calculated from the characteristics of the halogen lamp 1 has been reached. This is a means for knowing in advance that the end of life is 1.

FIG. 4 is a perspective view showing a state in which the optical fiber lighting devices of the first to third embodiments are assembled as a device. 4, the same components as those in FIGS. 1 to 3 are designated by the same reference numerals. Reference numeral 19 indicates a power switch.

[Fourth Embodiment] FIG. 5 shows a fourth embodiment of the optical fiber illuminating device of the present invention. In the fourth embodiment, an external control circuit 18, a D / A converter 17 for converting a digital signal into a voltage, and a selector 16 for switching between internal control and external control are added to the above-described third embodiment. Is. The voltage and current output to the halogen lamp 1 are detected by the voltage detector 9 and the current detector 11, respectively, and the information from these detectors 9 and 11 is comprehensively grasped by the external control circuit 18. However, it is intended to perform appropriate control.

FIG. 6 is a characteristic diagram showing the relationship between the total luminous flux, the current and the voltage due to the deterioration of the halogen lamp when driven by the halogen lamp drive circuit of the present invention. FIG. 7 is a characteristic diagram showing the relationship between the total luminous flux due to the halogen lamp deterioration and the current and voltage when the halogen lamp is driven by a conventional constant voltage power source.

As can be seen from the comparison of the characteristic diagrams of FIG. 6 and FIG. 7, in the present invention, the halogen lamp 1 is lit at a power (voltage × current of FIG. 6) slightly lower than the rated power of the halogen lamp 1 at the time of initial lighting. In the range of the maximum input power that can withstand 1, the light receiver 3 monitors the change in the amount of transmitted light of the monitor fiber 5 and feeds back the halogen lamp drive circuit 2 to control the power of the halogen lamp 1. Then, it is possible to correct the change in the light amount and maintain the total luminous flux at the initial lighting of the halogen lamp until the end of the halogen lamp life.

Therefore, until the end of the life of the halogen lamp,
It is possible to realize an optical fiber lighting device that uses a halogen lamp as a light source and that has high brightness, high output, and high stability.

[0023]

As described above, the optical fiber illuminator of the present invention uses the monitor fiber obtained by branching the amount of light emitted from the halogen lamp of the light emitting source from a part of the light projecting fiber. The amount of light radiated from the emission end of the light projecting fiber is made constant by performing feedback in accordance with the change in the amount of light and keeping the irradiation light of the halogen lamp of the light emitting source constant.

By using such an optical fiber illumination device for illumination for image processing, stable and accurate image information can be obtained, and sensitivity correction of the image processing equipment and aperture adjustment of the CCD camera are required. Can be used without.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of an optical fiber lighting device of the present invention.

FIG. 2 is an explanatory view showing a second embodiment of the optical fiber lighting device of the present invention.

FIG. 3 is an explanatory view showing a third embodiment of the optical fiber lighting device of the present invention.

FIG. 4 is a perspective view showing a state in which the optical fiber lighting devices of the first to third embodiments are assembled as a device.

FIG. 5 is an explanatory view showing a fourth embodiment of the optical fiber lighting device of the present invention.

FIG. 6 is a characteristic diagram showing the relationship between total luminous flux, current, and voltage due to halogen lamp deterioration when driven by the halogen lamp drive circuit of the present invention.

FIG. 7 is a characteristic diagram showing the relationship between total luminous flux due to halogen lamp deterioration and current and voltage when a halogen lamp is driven by a conventional constant voltage power supply.

[Explanation of symbols]

 1 Halogen lamp 2 Drive circuit 3 Light receiver 4 Light emitting fiber 5 Monitor fiber 6 Preamplifier 7 Comparator 8 Reference voltage setting device 9 Voltage detector 10 Voltage abnormality indicator 11 Current detector 12 Current abnormality indicator 13 Fiber binding ring 14 Fiber binding Ring 15 Fiber bundling ring 16 Selector 17 D / A converter 18 External control circuit 19 Power switch

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H05B 37/02 D 8715-3K (72) Inventor Fumio Mito 1-28 Kita-Otsuka, Toshima-ku, Tokyo No. 3 Hayashiki Keikogyo Co., Ltd. (72) Inventor Hiroaki Tanaka 1-28 Kitaotsuka, Toshima-ku, Tokyo No. 3 Hayashiki Keikogyo Co., Ltd. (72) Inventor Eiichi Ogawa Kitaotsuka, Toshima-ku, Tokyo 1-chome No. 28 No. 3 Hayashiki Keiko Industry Co., Ltd.

Claims (3)

[Claims] 1. A halogen lamp as a light source, a light projecting fiber in which a plurality of optical fibers for guiding the light of the halogen lamp are bundled, a light receiver, and a monitor for guiding a part of the light projecting fiber to the light receiver. A fiber and a feedback loop that feeds back the output of the light receiver to the driving circuit of the halogen lamp are provided, and the output of the halogen lamp is corrected according to the change in the amount of light emitted from the halogen lamp, and the light projection is performed. An optical fiber illuminating device, characterized in that the amount of light emitted from a fiber emitting end is kept constant. 2. A comparator for comparing the output voltage from the photodetector with a reference voltage, and a voltage abnormality display for judging and displaying an abnormality when the output voltage exceeds a predetermined range as a result of comparison by the comparator. The optical fiber illuminator according to claim 1, further comprising: 3. A current detector for detecting a current value flowing through the halogen lamp, and a current abnormality indicator for displaying an abnormality when the current value exceeds a limit current value as a result of detection by the current detector. The optical fiber lighting device according to claim 1 or 2, further comprising: