JP2001174410A - Lighting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting apparatus capable of holding the quantity of emitted light to a constant level. SOLUTION: The lighting apparatus for allowing the light emitted from a light source 11 to be incident on the end part of a bundled fiber 15 consisting of a plurality of fibers and irradiating an object with the light emitted from the other end of the bundled fiber 15 is equipped with a quantity-of-light monitor 18 receiving the light emitted from the fiber branched from a part of the bundled fiber 15 and the quantity of light applied to the object is adjusted by the quantity-of-light monitor 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device in which light emitted from a light source is made incident on a bundle fiber composed of a plurality of optical fibers and guided to a predetermined position.

[0002]

2. Description of the Related Art A lighting device using an optical fiber has been proposed in, for example, Japanese Patent Application Laid-Open No. 2-110356. This device is a lighting device for irradiating an object linearly by irradiating light from a lamp to an end portion of a bundle fiber and arranging the other end portions linearly one by one. As an illumination device for controlling the light source light amount to be constant, for example, Japanese Patent Application Laid-Open No. 8-130680 has been proposed. This device irradiates the object with light emitted from a light source and inputs the light to an optical sensor. Then, the signal photoelectrically converted by this optical sensor is converted into a digital value,
The control amount is determined by comparing with a preset reference value, and a control signal is supplied to a power source for driving the light source so as to keep the light source light amount constant.

[0003]

However, the above-described devices have the following problems. That is, in the lighting device proposed in Japanese Patent Laid-Open No. 2-110356, the light source light quantity cannot be kept constant or a predetermined value. Therefore, when a plurality of lighting devices are arranged in parallel as shown in FIG. There is a problem that the brightness differs between the left and right lighting devices. Even if the left and right brightnesses can be equalized, there is an individual difference in the decrease in the amount of light due to the deterioration of the lamp. As a result, uniform illumination conditions cannot be ensured. For example, when such an illumination device is used as illumination for inspection, there is a problem that an inspection result changes due to a difference in brightness. .

On the other hand, a lighting device proposed in Japanese Patent Application Laid-Open No. Hei 8-130680 irradiates emitted light to an object and impinges it on an optical sensor, and controls a light source drive voltage based on the output. However, if the optical sensor is placed side by side with the target, the amount of light received will decrease even if the light sensor light receiving unit becomes dirty. There was a problem that it was not possible to distinguish whether the light source was caused by the light source, and as a result, the light source light amount could not be kept constant. In addition, it is conceivable that the light sensor is disposed inside the lighting device so as not to be contaminated.In such a case, however, the temperature inside the lighting device greatly changes due to the heat generated by the light source. The output value of the optical sensor greatly fluctuates, and as a result, there is a problem that the light amount of the light source cannot be kept constant. Furthermore, if the directivity of the light source lamp is not uniform and the adjustment of the optical system is not sufficient, the relationship between the amount of light emitted from the fiber and the output of the optical sensor is not constant. There was a problem that the light amount was not constant.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and employs the following construction. In an illuminating device in which light emitted from a light source is incident on an end of a bundle fiber composed of a plurality of fibers and irradiates a target with light emitted from the other end of the bundle fiber, a part of the bundle fiber is branched. A light quantity monitor for receiving the light emitted from the branched fiber is provided, and the light quantity monitor is adjusted using the light quantity monitor.

Further, the light amount monitor is housed in a case separate from the case for housing the light source.

Further, the light amount of the light source is controlled based on the output value of the light amount monitor.

Further, a filter for transmitting light is provided between the light source and the incident end of the bundle fiber, and the light transmittance of the filter is controlled based on an output value of the light amount monitor.

[0009]

FIG. 1 is a block diagram of a lighting device showing an embodiment of the present invention. Light 13 emitted from the light source lamp 11 is condensed at one point by the elliptical mirror 12.
A quartz rod 14 is arranged at the light condensing point to guide the incident light to the emission end by internal reflection, mix light having different incident angles in the process, and reduce the uneven light amount at the emission end. Light emitted from the other end of the quartz rod 14 is a bundle fiber 1 formed by bundling a plurality of optical fibers.
5 is incident. Here, 10 is a light source lamp 11
And a lamp house for storing the quartz rod 14,
Reference numeral 16 denotes a fixture for fixing the bundle fiber 15 to the lamp house 10.

The bundle fiber 15 is bifurcated on the way, and one is linearly arranged to form a light guide 17 for linearly irradiating the object (20 denotes an optical fiber arranged linearly). ) And the other is guided to a light quantity monitor 18 comprising an optical sensor. The light amount monitor 18 outputs a signal corresponding to the received light amount, and is housed in a case 19 different from the lamp house 10 so that dirt does not adhere. Since the case 19 does not contain anything that generates heat like a lamp, the temperature inside the case is always stable, and the light amount monitor 18 and its peripheral circuits may drift due to temperature changes. There is no.

The optical fiber guided to the light amount monitor 18 is preferably a small-diameter bundle fiber in which a plurality of fibers are bundled in order to reduce the influence of disconnection. For example, several tens to several hundreds of fibers are bundled. use. In addition, when there is uneven light amount at the input end of the bundle fiber 15, the light amount monitor 18 is connected to the light amount monitor 18 in order to eliminate the problem that the output value of the light amount monitor 18 does not necessarily represent the light amount at the output end of the bundle fiber 15. At the input end to the bundle fiber 15 (from the quartz rod 14), as many fibers as possible are selected at different positions constituting the bundle fiber so that the outgoing light is not deflected. I try not to.

In this embodiment, a lamp is used as a light source, and light is guided to the fiber by using a reflection optical system. However, it goes without saying that the present invention is not limited to the above-described embodiment. For example, the light source may be a laser instead of a lamp, or a condensing optical system using a lens instead of a reflecting optical system using an elliptical mirror. Further, the fiber emitting end is not limited to a linear array arranged in a straight line, and circular illumination in a bundled state is also possible.

With the above configuration, the light amount monitor 18
As a result, an electric signal proportional to the amount of light emitted from the lighting device can be obtained, so that the amount of light emitted from the device can be controlled to a predetermined level based on the electric signal. Hereinafter, a specific control example will be described.

FIG. 2 is an operation block diagram showing an example in which the output of the light amount monitor 18 is used to control the output light amount to the object 27 constant in the illumination device of FIG. The output of the light amount monitor 18 for receiving the light emitted from the branch fiber is
The data is converted into a digital value by the A / D converter 21 and input to the control unit 22. The control unit 22 is provided with a control target value, compares it with the output from the light amount monitor 18, determines a control signal according to, for example, PID control, and feeds it back to the drive power supply 23 of the light source lamp 11, The light amount of the light source lamp 11 is adjusted. As the control signal, for example, a voltage signal when a halogen lamp is used as a light source, and a current signal when a laser is used as a light source. Good.

Further, even if the light amount of the light source itself is not controlled, as shown in the operation block diagram of FIG.
A filter 24 such as a D filter is inserted into the optical path between the light source lamp 11 and the incident end of the bundle fiber 15, and the filters 24 are moved by a motor driver 25 or a motor 26 so that light is incident on the filter 24. By changing the position, it is also possible to control the amount of transmitted light and adjust the amount of light irradiated to the object 27.

The above-mentioned control target value may be a predetermined fixed value, or the target value may change every moment according to, for example, the reflectance of the object. This is particularly effective, for example, when configuring an inspection device from a plurality of lighting devices and cameras, when controlling the light amounts of all the lighting devices using a specific camera output.

[0017]

As described in detail above, according to the device of the present invention, the amount of emitted light (or the amount of irradiated light) can be maintained at a predetermined level. Also, uniform illumination conditions can be obtained between these devices. In addition, the light amount monitor is housed in a special case so that the light receiving section does not become dirty and the temperature does not change, so that the output is stable and the emitted light amount can be accurately maintained at a predetermined level. it can. Furthermore, since the fiber guided to the light amount monitor is extracted on average from the entire bundle fiber so that the emitted light is not deflected, there is a variation in the directivity of the light source lamp and a problem in adjustment of the optical system. Even if this is the case, the relationship between the output of the light amount monitor and the output light amount at the tip of the bundle fiber can be kept constant.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a lighting device according to an embodiment of the present invention.

FIG. 2 is an operation block diagram showing an example of controlling the emitted light amount of the lighting device of FIG. 1 using the output of a light amount monitor.

FIG. 3 is an operation block diagram showing another example of controlling the emitted light amount of the illumination device of FIG. 1 using the output of a light amount monitor.

[Explanation of symbols]

 Reference Signs List 10 lamp house, 11 light source lamp, 12 elliptical mirror, 13 light emitted from light source lamp, 14 quartz rod, 15 bundle fiber, 17 light guide, 18 light quantity monitor, 19 light quantity monitor case, 21 A / D converter, 22 control part, 23 power supply, 24 filter, 26 motor, 27 object.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Kawamura 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Hiroyuki Sugiura 1-1-2 Marunouchi, Chiyoda-ku, Tokyo, Japan F-term (reference) in this steel pipe Co., Ltd. 2G051 BB17 BC01 CA20 CB10 CC17 2G059 GG05 JJ17 JJ25 KK01 NN05

Claims (4)

[Claims] 1. An illumination device for irradiating light emitted from a light source to an end of a bundle fiber composed of a plurality of fibers and irradiating a target with light emitted from the other end of the bundle fiber. An illumination device, comprising: a light amount monitor for receiving light emitted from the branched fiber by branching a portion, and adjusting an irradiation light amount to the object by using the light amount monitor. 2. The lighting device according to claim 1, wherein the light amount monitor is housed in a case separate from a case that houses the light source. 3. The lighting device according to claim 1, wherein the light amount of the light source is controlled based on an output value of the light amount monitor. 4. A light transmitting filter is provided between the light source and the incident end of the bundle fiber, and a light transmittance of the filter is controlled based on an output value of the light quantity monitor. The lighting device according to claim 1.