JPH06281868A - Light source device for electronic endoscope - Google Patents

Abstract

PURPOSE:To favorably hold the output light quantity of a light source corresponding to the change with the lapse of time of a light source lamp and to execute an analogous simple control of the light quantity. CONSTITUTION:A photosensor 27 is arranged by burying it in a receiving member 26 formed out of a white resin material and the output light of a xenon lamp 21 is detected by means of the photosensor 27 and a light quantity detecting part 28. The opening amount of a diaphragm 23 is adjusted by means of a diaphragm driving circuit 24 based on the detected value by the photosensor 27. It is also possible to control the voltage of the light source of a power source part 20 for the light source based on the detected value of the photosensor 27. Consequently, even when a change with the lapse of time arises, a constant output light quantity is obtained. At the same time, the diaphragm 23 performs several steps of light quantity control in accordance with the control for an electronic shutter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a light source device for an electronic endoscope,
In particular, the present invention relates to adjustment of the amount of light that accompanies deterioration of a light source lamp that supplies irradiation light into the body to be observed.

[0002]

2. Description of the Related Art A solid-state image sensor as an image sensor,
That is, an electronic endoscope device using a CCD (Charge Coupled Device) is well known, and in this electronic endoscope device, a light source device is used to illuminate the inside of an object to be observed. FIG. 3 shows a schematic configuration of a conventional electronic endoscope apparatus,
As shown in the figure, the electronic endoscope device is composed of an electronic endoscope 1 which is a scope, an external processor device 2, and a light source device 3. In the electronic endoscope 1, a CCD 5 is arranged via an optical system member 4, and a light guide 6 is arranged from the light source device 3.

Further, the external processor device 2 is provided with a video signal processing circuit 8 via an amplifier 7, and the video signal processing circuit 8 executes various processes such as gamma correction and white balance. This video signal processing circuit 8
A monitor 10 is connected to the monitor 10 via an output unit (encoder or the like) 9. Further, the light source device 3 is provided with, for example, a xenon lamp 11, a diaphragm 12, and a diaphragm drive circuit 13.

With such a configuration, the light from the xenon lamp 11 is supplied to the light guide 6 after the light amount is adjusted by the diaphragm 12, and is irradiated as observation light from the tip of the electronic endoscope 1 into the body to be observed. It On the other hand, the image inside the body to be observed is captured by the CCD 5 via the optical system member 4, the video signal output from the CCD 5 is supplied to the video signal processing circuit 8 via the amplifier 7, and is subjected to image processing there. An image of the inside of the observed body is displayed on the monitor 10.

At this time, the output of the amplifier 7 is supplied to the diaphragm drive circuit 13, and the brightness (light quantity) of the video signal is judged from the output of the amplifier 7. If the light quantity is insufficient, the aperture of the diaphragm 12 is opened. When the light amount is excessively large, the light amount control (ALC) is performed so that the aperture of the diaphragm 12 is made small. According to this, even if underexposure (variation in pixel signal level) occurs due to electronic shutter control,
The brightness of the image is satisfactorily adjusted, and the image having the optimum brightness is displayed on the monitor 10.

[0006]

By the way, in the above-mentioned conventional light source device for an electronic endoscope, there is a problem that the light amount of the xenon lamp 11 and the like shown in FIG. 3 changes with time, and the light source output changes. . That is, as shown in FIG.
The light source lamp such as the xenon lamp 11 has a characteristic that the illuminance (unit lux) first decreases with a relatively large curve and then decreases with a gentle curve, and the output light amount decreases with time. Then, the decrease in the light amount due to the deterioration of the light source lamp was simultaneously solved by the light amount control by the diaphragm 12. However, since this light amount control is analog control, the overall control including drive control of the diaphragm 12 becomes complicated. In addition, if the time-dependent change of the light source lamp is separately corrected, other control can be easily performed.

In addition, the applicant of the present invention, in the diaphragm 12,
When the amount of light is sufficient, it is proposed to perform simple digital control in several steps so that the diaphragm 12 is stopped so that, for example, the tip of the electronic endoscope does not overheat. Further, in the above light amount control (ALC), a simple digital control of several steps can be performed so as to solve the underexposure in correspondence with the electronic shutter speed. However, in these cases, there is a problem in that the aging of the light source lamp cannot be compensated, and the brightness decreases with time.

The present invention has been made in view of the above problems, and an object thereof is to make it possible to keep the output light amount of a light source excellent in response to the change with time of the light source lamp.
An object of the present invention is to provide a light source device for an electronic endoscope that can also perform analog simple light amount control.

[0009]

In order to achieve the above object, the invention according to the first aspect of the present invention is a light source device for an electronic endoscope for supplying observation light into an object to be observed, wherein light is emitted from a light source lamp. An optical sensor for detecting the output state of the emitted light,
An adjustment circuit for adjusting the output light amount based on the detection value of the optical sensor is provided. The invention according to a second aspect is characterized in that a receiving member for receiving the light guide of the electronic endoscope side optical connector is formed of a white resin material, and the optical sensor is embedded in the receiving member. According to a third aspect of the invention, as the adjusting circuit, an aperture driving circuit that variably controls an aperture based on a detection value of an optical sensor, or a light source power supply unit that variably controls a light source power based on a detection value of the optical sensor. It is characterized by being used.

[0010]

According to the above construction, when the output light of the light source lamp is directly detected by the optical sensor and the light source lamp is deteriorated due to a change with time, the output of the light source device is adjusted by finely adjusting the diaphragm. The amount of light increases. Therefore, in the state where the deterioration of the light source lamp is compensated, sufficient light is applied to the inside of the object to be observed through the light guide. In this case, the light source power source itself can be controlled instead of adjusting the diaphragm.

Further, in the above description, the optical sensor can be embedded in the receiving member made of a white resin material, whereby the receiving member can obtain the wavelength integration effect, the dimming effect, etc. The amount of output light can be detected efficiently.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of a light source device for an electronic endoscope according to an embodiment, and a CCD 14 shown in the drawing is arranged at the tip of an electronic endoscope which is a scope. . This C
The CD 14 includes an amplifier 15 and an image processing circuit 16
Are connected, and electronic shutter control is executed by the image processing process circuit 16, and at the same time, the video signal is processed for gamma correction, white balance, and the like. In addition, the image processing process circuit 16 stores the video signal in the memory, and the like.
The output of 6 is supplied to the monitor. Further, a light guide 17 is provided up to the tip of the electronic endoscope, and the light guide 17 is optically connected to a light source device 19 by an optical connector 18.

In the light source device 19, the light source power source section 2 is provided.
0, xenon lamp (or halogen lamp may be used) 2
1, an optical system member 22 having a filter and the like, and a diaphragm 23 are provided.
Color filter disks for (red), G (green), and B (blue) are provided, and a diaphragm drive circuit 24 for varying the opening amount is connected to the diaphragm 23. In the embodiment, the aperture drive circuit 24 is supplied with a digital control signal for controlling the light amount in two stages (three stages or linear multi stages may be used) from the image processing circuit 16, and the digital control signal is, for example, an electronic signal. It is formed by the state of shutter control. That is, in order to prevent the tip end from being overheated by the irradiation light, it is possible to form a digital control signal for closing the diaphragm 23 when the electronic shutter is extremely fast. Also,
The electronic shutter is used to adjust differences in the movement of the subject, white balance, color temperature, and the like. At this time, the amount of light (charge accumulated in the CCD) is insufficient due to changes in the electronic shutter speed. The light amount on the light source side may be controlled stepwise in conjunction with the operation.

A receiving member 26 for receiving the light guide 17 when the optical connector 18 is attached or detached is provided. The receiving member 26 is made of a white resin material (polyacetal or the like) and is opened in the receiving member 26. Optical sensor (photodiode, phototransistor, etc.) in the hole 2
7 is embedded. Therefore, this optical sensor 27
Instead of the direct light emitted from the diaphragm 23 toward the light guide 17, the light that has arrived via the receiving member 26 made of white resin is detected. According to this, the receiving member 26 serves as a filter for wavelength integration, diffusion and dimming, and the light output state of the xenon lamp 21 can be accurately detected.

A light amount detection unit 28 is connected to the optical sensor 27, and the light amount detection unit 28 measures the change over time by detecting the light amount per unit time. The measured light amount signal is used to drive the diaphragm. It is supplied to the circuit 24. In the diaphragm drive circuit 24, based on the detected light amount signal,
The aperture amount of the diaphragm 12 is controlled separately from the control of the light amount control signal from the image signal processing circuit 16.

The embodiment is constructed as described above, and when the xenon lamp 21 is turned on by the control of the light source power source section 20 of FIG. 1, the light of the xenon lamp 21 is supplied to the light guide 17 through the optical system member 22 and the diaphragm 23. To be done. The light introduced into the light guide 17 is radiated from the tip of the electronic endoscope to the inside of the observed body, and the subject in the observed body that appears due to this is captured by the CCD 14. In this CCD 14, the shutter is controlled by an electronic shutter drive circuit in the image processing circuit 16, and when the shutter speed is high, the charges accumulated in a short time are read, and when the shutter speed is low, the charges accumulated in a long time are read out. As a result, a video signal is formed. Then, this video signal is supplied to the image processing process circuit 16 via the amplifier 15, and the image in the observed body is displayed on the monitor by performing a predetermined image processing here.

During the image processing operation, the image processing circuit 16 supplies a two-stage digital signal to the diaphragm drive circuit 24 in accordance with the electronic shutter control. Then, in this drive circuit 24, for example, as shown in FIG.
3 will be driven to positions A1 and A2. As a result, it is possible to prevent overheating due to the irradiation light, and it is also possible to compensate for the lack of light amount caused by driving the electronic shutter. In this case, it is possible to compensate for the brightness.

At this time, at the same time, the optical sensor 27 in the receiving member 26 detects the change over time shown in FIG. 4, and the output of the light amount detecting section 28 is supplied to the diaphragm drive circuit 24. When the amount of light detected by the light amount detector 28 decreases, the diaphragm 23 is driven to the positions B1 and B2 shown by dotted lines so as to widen the opening 100, as shown in FIG. Therefore, even if the xenon lamp 21 changes with time, the amount of light output from the light source device 19 is always constant.

In the above embodiment, the deficiency of the light amount due to the change with time is compensated by driving the diaphragm 23, but this light amount adjustment can also be executed by the light source power source section 20.
That is, the detection signal of the light amount detecting section 28 is sent to the light source power source section 20.
When the voltage of the light source power source 20 is increased in association with the decrease of the detection signal due to the change over time, the light amount of the xenon lamp 21 itself increases. Therefore, also in this case, it is possible to compensate for the aged deterioration of the xenon lamp 21.

In the above embodiment, the digital signal is supplied from the image processing circuit 16 to the diaphragm drive circuit 24, but the present invention can be applied to the case where an analog signal is supplied.

[0021]

As described above, according to the present invention,
The light source device is provided with an optical sensor that detects the output state of the light source lamp, and the output light amount is adjusted by driving the diaphragm or changing the light source power source based on the detection value of the optical sensor. Even if the light source lamp changes with time, the output light amount of the light source can be favorably maintained, and simple digital light amount control can be executed.

In the above, the receiving member for receiving the light guide may be formed of a white resin material, and the optical sensor may be embedded in the receiving member. According to this, the receiving member has wavelength integration, diffusion and diffusion. It has an advantage that it serves as a filter for dimming, enables accurate detection, and does not require a special configuration for detection, and has a simple configuration.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a light source device for an electronic endoscope according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a diaphragm driving state of the embodiment.

FIG. 3 is a block diagram showing a schematic configuration of a conventional electronic endoscope apparatus.

FIG. 4 is a graph showing a change over time of a light source lamp.

[Explanation of symbols]

 5, 14 ... CCD, 6, 17 ... Light guide, 3, 19 ... Light source device, 12, 23 ... Aperture, 13, 24 ... Aperture drive circuit, 20 ... Light source power supply section, 21 ... Xenon lamp, 26 ... Receiving member, 27 ... Optical sensor, 28 ...

Claims (3)

[Claims] 1. An electronic endoscope light source device for supplying observation light into an object to be observed, wherein an optical sensor for detecting an output state of light emitted from a light source lamp and a detection value of the optical sensor are used. A light source device for an electronic endoscope, which is provided with an adjusting circuit for adjusting an output light amount. 2. A receiving member for receiving a light guide of an electronic endoscope side optical connector is made of a white resin material, and the optical sensor is embedded in the receiving member. A light source device for an electronic endoscope as described above. 3. As the adjusting circuit, a diaphragm drive circuit that variably controls an aperture based on a detection value of an optical sensor, or a light source power supply unit that variably controls a light source power based on a detection value of the optical sensor is used. The light source device for an electronic endoscope according to the first claim.