JP2001014917A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure changes in light intensity by monitoring the light intensity with a monitor fiber and dispensing with an attachment part generating a play in a light receiver part, so as not to be affected by temperature changes, and to accurately control the light intensity using a simple structure for adding the monitor fiber and an external light intensity controller, without requiring special temperature correction circuit or the like. SOLUTION: This light source device comprises a light guide 1, a monitor fiber 2 formed by blanching a portion of the light guide 1, provided with a light receiver 3 in a tip part, an external light intensity controller 4 generating a control signal for keeping light intensity constant on the basis of a signal of the light receiver 3, and a light source device body 5 having an external light intensity control function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device used for illumination of an image processing / inspection apparatus, and for illumination for medical treatment or illumination.

[0002]

2. Description of the Related Art Conventionally, in order to keep the amount of illumination light constant, the light emitted from a light source such as a light bulb is monitored by an optical sensor, and the light amount of the light source is made constant based on the output of the optical sensor. There is a light source device to which a function of controlling a power supply voltage is added. Among them, as an example of using a monitor fiber for monitoring a light amount by branching a part of the light emitting fiber at an incident end of the light emitting fiber (light guide),
JP-A-5-32673, JP-A-8-32782
No. 6 is cited.

[0003] Furthermore, the present applicant has filed Japanese Patent Application No. 10-259.
At 408, an embodiment (FIG. 5) in which the photodetector 3 is incorporated in the external light quantity control device 4 is shown. Usually, the monitor fiber 2 and the photodetector 3 are attached to each other as shown in FIG. 2 is often inserted into a connector 9 attached to the external light quantity control device 4. For this reason, due to variations in the outer diameter of the connector 9 and the outer diameter of the monitor fiber 2, rattling occurs at this mounting portion, and the light receiving device 3
As a result, the angle of incidence of the light incident on the optical fiber or the distance between the tip of the monitor fiber 2 and the light receiver 3 becomes inconsistent. Cause the problem of not being able to do it.

Further, in the above-described example, since an electronic circuit section such as a photodetector and a control device for controlling the amount of light is built in the light source device main body and is close to a heat source such as a light source lamp, the ambient temperature is greatly reduced. Changes to For this reason, there arises a problem that the light amount cannot be accurately set by a control device including an electronic circuit including a semiconductor such as a photodetector or an IC which is easily affected by a temperature change. Furthermore, since the inside of the light source device body is constantly exposed to high temperatures, the semiconductor is likely to be deteriorated and there is also a problem of durability.

[0005]

Therefore, in the present invention,
It is an object of the present invention to eliminate the above-mentioned inconveniences caused by the attachment of a monitor fiber or a change in the ambient temperature of a light receiving unit or a control device, and to provide a highly accurate and inexpensive light source device.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have provided a light receiving device and a control device outside the light source device main body with little temperature change and a light receiving device. The present invention has been completed by conceiving that the monitor fiber is integrally provided at the end of the monitor fiber without a connector.

That is, the present invention provides (1) a monitor fiber in which a part of the light guide is branched in a light source device using a light guide in which a number of optical fibers for guiding light emitted from a light source to an object are bundled. And a light receiver that receives the light of the monitor fiber, an external light amount control device that generates a control signal for keeping the light amount constant based on a signal from the light receiver, and a light amount that can be externally controlled. A light source device comprising a light source device main body having an external light amount control function. (2) The light source device according to claim 1, wherein a light receiver is provided at a tip of the monitor fiber.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a light guide for irradiating the object with light from a light source, 2 a monitor fiber for monitoring the amount of light obtained by branching a part of the light guide 1 at an incident end 1a of the light guide, and 3 a light receiver. Reference numeral 4 denotes an external light amount control device that generates a control signal for keeping the light amount constant based on the light amount monitored by the light receiver. Reference numeral 5 denotes a light source device body having an external light amount control function capable of controlling the light amount from outside. is there. 6 is an external light quantity control input terminal provided on the light source device main body 5, 7 is a covering material of the light guide 1, 8 is a light receiver 3
Between the external light intensity control device 4 or the external light intensity control device 4
And a lead wire connecting between the external light intensity control input terminal 6 and the external light intensity control input terminal 6.

Next, the light guide 1 which is a feature of the present invention.
Will be described in detail with reference to FIG. As shown in FIG. 2, the light guide 1 has an incident end (tip) 1a,
In order to monitor the amount of light, a monitor fiber 2 is provided in which a part of the light guide 1 is branched. Here, in the present invention,
In order to eliminate the above-mentioned inconvenience caused by the play of attaching the monitor fiber 2 to the light receiver 3, direct connection is made without any connection device such as a connector. By doing so, since the light receiving unit 3 photoelectrically converts the optical signal into an electric signal, a stable light amount signal can be supplied to the next external control device 4, and highly accurate light amount control can be performed. The connection between the light receiving unit 3 and the external control device 4 may be made not only by a lead wire but also by a connector such as a connector to facilitate maintenance.

Next, the operation of the light source device of the present invention will be described. The light incident on the monitor fiber 2 then enters the light receiver 3 and is converted into an electric signal. Next, the light quantity signal converted into the electric signal is supplied to the external light quantity control device 4 via the lead wire 8.
To enter. Here, the light amount is compared with a light amount set value (target value), and a light amount control signal is generated.

Finally, the light quantity control signal is input to the external light quantity control input terminal 6 of the light source device body 5, and the light quantity control feedback control is performed, so that the light quantity can be made constant. Here, various light sensors such as a phototransistor and a photodiode can be used as the light receiver 3. Further, in order to obtain a stable optical signal, it is desirable that the photodetector 3 incorporates an amplifier constituted by an electronic circuit or the like. In addition,
In the description so far, the lead wire 8 is connected between the light receiver 3 and the external light amount control device 4 and between the external light amount control device 4 and the light source device body 5.
However, other connection means such as a wireless interface using a transmission / reception device may be used.

Lastly, the external light amount control device 4 will be briefly described. The external light amount control device 4 includes a known light amount setting circuit, a comparison circuit, a light amount control circuit, and the like. Also, as for the light amount control method, various selections such as a well-known analog method and a digital method are possible. Further, the conditions relating to the interface, such as the signal type, the level, and the number of signal lines of the light amount control signal, may be adapted according to the specifications of the light source device main body 5. In the above-described embodiment, an example has been described in which the light amount of one light source device is controlled by one external light amount control device. It is also conceivable to use a type of external light amount control device.

As described above, according to the present invention, the light quantity is measured at the incident end 1a of the light guide 1 by the monitor fiber 2 obtained by branching a part of the light guide 1. There is no play in the insertion of the fiber, and the change in the amount of light can be measured accurately. Further, since the light receiver 3 and the external light amount control device 4 are provided outside the light source device main body 5, stable light amount control can be realized without being affected by a change in ambient temperature.

[0014]

According to the present invention, the amount of light can be accurately measured by monitoring the amount of light with the monitor fiber, and furthermore, since the light receiving portion has no mounting portion that causes backlash and is not affected by the temperature change. Further, accurate light quantity control can be achieved with a simple structure that does not require a special temperature correction circuit or the like and adds a monitor fiber and an external light quantity control device. Further, the light amount of a plurality of light source devices can be controlled by a multi-type external light amount control device.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a light source device of the present invention.

FIG. 2 is a longitudinal sectional view of a light guide used in the embodiment of the light source device of the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional example.

FIG. 4 is a detailed view showing how to attach a monitor fiber to the light receiving unit in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light guide 1a Light guide incidence end 1b Light guide incidence part 2 Monitor fiber 3 Light receiver 4 External light quantity control device 5 Light source device body 6 External light quantity control input terminal 7 Coating material 8 Lead wire 9 Connector

Claims (2)

[Claims] 1. A light source device using a light guide that bundles a number of optical fibers for guiding light emitted from a light source to an object, a light guide including a monitor fiber in which a part of the light guide is branched, and A light receiver that receives the light of the monitor fiber, an external light amount control device that generates a control signal for keeping the light amount constant based on the signal of the light receiver,
A light source device comprising a light source device body having an external light amount control function capable of externally controlling the light amount. 2. The light source device according to claim 1, wherein a light receiver is provided at a tip of the monitor fiber.