JP2500931B2 - Endoscope device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an endoscope apparatus having an image pickup means built in a distal end of an endoscope.

[Prior art]

In recent years, an endoscope apparatus has been developed in which a solid-state image sensor such as a CCD is provided at the tip of an endoscope to perform color imaging. The number of pixels cannot be increased because the image sensor is provided in a narrow space such as the tip of the endoscope. Therefore, color imaging is performed in the frame sequential direction in which all pixels can be effectively used. An example of such a device is described in JP-A-53-90685. That is, the illumination light from the light source lamp is sequentially filtered by red (R), green (G), and blue (B), and images are taken in sequence under the illumination light of three colors. The component signals are obtained, and the component signals of three colors are combined for each pixel to generate a color image signal.

Here, the illumination light is guided from the light source lamp to the tip of the endoscope through a light guide formed of an optical fiber bundle, and is irradiated to the imaging site from there. A lens is provided on the front surface of the light guide for irradiation of this illumination light, and an objective lens is also provided on the front surface of the CCD for imaging. These lenses are held at the tip of the endoscope by a metal frame. Therefore, the temperature of the metal frame may rise due to the heat from the irradiation light transmitted through the light guide. In general, a dark current flows through the CCD, and this dark current increases as the ambient temperature rises. Therefore, in such a conventional endoscope image pickup device, there is a drawback that the image quality is deteriorated according to the temperature rise of the tip portion due to the heat from the illumination light.

〔Purpose〕

This invention has been made to cope with the above-mentioned circumstances, and its object is an endoscope apparatus in which a solid-state imaging device such as a CCD is built in the tip portion, and the dark current of the CCD increases due to the temperature rise of the tip portion, It is to prevent the image quality from deteriorating.

〔Overview〕

An object of the present invention is to provide an endoscope having a light guide for irradiating illumination light and having an image pickup element built in at a distal end portion thereof, and a light source unit having a light source lamp for connecting the endoscope to enter the illumination light into the light guide. In the endoscope apparatus provided, a temperature sensor provided in the vicinity of the image sensor, a temperature detection circuit for detecting that the temperature measured by the temperature sensor is equal to or higher than a predetermined temperature, and the detection circuit is a temperature sensor. And a means for reducing the amount of illumination light incident on the light guide from the light source lamp when it is detected that the measured temperature is higher than or equal to a predetermined temperature. Example] An embodiment of the endoscope apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment. This embodiment includes an endoscope body 10, a light source unit 12, and a monitor device 14. A solid-state imaging device (CCD in this case) 22 that images a target site via an objective lens 20 is provided at the tip of the endoscope body 10. Further, the endoscope body 10 is also provided with a light guide 24 formed of an optical fiber bundle that guides the illumination light from the light source unit 12 to the distal end portion and illuminates the target site from the distal end portion. A temperature sensor 26 such as a thermistor is provided near the CCD 22 at the tip of the endoscope. Second
As shown in the drawing, a distal end constituent portion 40 made of metal such as stainless steel is built in the distal end of the endoscope, and the light guide 24, the objective lens 20, and the CCD 22 are fixed by the distal end constituent portion 40.

The light source unit 12 includes a light source lamp 28 that generates illumination light, and the illumination light from the light source lamp 28 is incident on one end of the light guide 24 via the diaphragm 30. The image signal output from the CCD 22 is supplied to the video processor 36 in the light source unit 12 and converted into a signal in a format suitable for display on the monitor device 14. The output signal of the temperature sensor 26 is input to the temperature detection circuit 32 in the light source unit 12. Details of the temperature detection circuit 32 are shown in FIG. The resistor 40 and the thermistor 26 are connected in series between the power source Vcc and the ground, and the connection point is connected to the (+) input end of the comparator 42. Resistance 44, variable resistance 4 between power supply Vcc and ground
6. The resistor 48 is connected in series, and the variable point of the variable resistor 46 is connected to the (−) input terminal of the comparator 42. The output of the comparator 42 is connected to the (−) input terminal of the comparator 42 via the resistor 50.
Thus, the temperature detection circuit 32 outputs the detection signal only when the output signal of the thermistor 26 is larger than the reference signal determined by the variable resistor 46, the resistors 44, 48, 50 and the power supply Vcc. The output of the temperature detection circuit 32 is supplied to the aperture control circuit 34 and the video processor 36. As a result, the aperture value of the aperture 30 is controlled according to the output of the temperature sensor 26.

Next, the operation of this embodiment will be described. Insert the tip of the endoscope body 10 into a target site, for example, a body cavity, and
Turn on 28. The part illuminated by the illuminating light from this is picked up by the CCD 22, and the image signal is supplied to the monitor device 14 via the video processor 36 and displayed. On the other hand, the output of the temperature sensor 26 is supplied to the temperature detection circuit 32. If the output of the temperature sensor 26 is higher than the reference signal, the temperature detection circuit 32
The detection signal is generated from the video processor
A warning that the temperature of the tip has risen too much and the amount of illumination light should be reduced is displayed in superimposition on the image. In this embodiment, since the detection signal is supplied to the diaphragm control circuit 34, in this case, the diaphragm 30 is automatically controlled and the amount of illumination light incident on the light guide 24 is reduced.
As a result, the amount of illumination light transmitted through the light guide 24 decreases, and the temperature rise of the endoscope distal end portion due to heat from the illumination light (mainly reflection from the illumination lens) is stopped. As a result, the tip of the endoscope is always kept below a certain temperature, and CC
The dark current of D is prevented from increasing.

As described above, according to the first embodiment, in the endoscope apparatus having the CCD at the tip of the endoscope, the temperature sensor is provided at the tip to detect the temperature of the tip so that the tip is always below a certain temperature. Since it is controlled, the CCD is heated by the heat from the illumination light transmitted through the light guide and the dark current is prevented from increasing.

〔The invention's effect〕

As described above, according to the present invention, a dark current of a solid-state imaging device such as a CCD provided at the tip end due to heat caused by illumination light increases, and an endoscope device that can prevent deterioration of image quality is provided. Provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an endoscope apparatus according to the present invention, FIG. 2 is a sectional view showing details of a tip end portion of this embodiment, and FIG. 3 is a temperature detection of this embodiment. It is a block diagram of a circuit. 10 ... Endoscope body 12 ... Light source unit 14 ... Monitor device 22 ... CCD 24 ... Light guide 26 ... Temperature sensor 28 ... Light source lamp 30 ... Aperture 32 ... Temperature detection circuit 36 ... Video processor

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hideki Shimonaka 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Masato Toda 2-43-2 Hatagaya, Shibuya-ku, Tokyo No. Olympus Optical Industry Co., Ltd. Judging Chairman Masuo Yamada Judge Keiichi Hashimoto Judge Tatsuya Yamazaki (56) References JP 59-88135 (JP, A) JP 56-148333 (JP, A) Kai 57-49426 (JP, A) JP 59-69026 (JP, A)

Claims (1)

(57) [Claims] 1. A light source unit having an endoscope having a light guide for irradiating illumination light and having an image pickup element built in at a distal end portion thereof, and a light source lamp for connecting the endoscope to the illumination light for making the illumination light incident on the light guide. An endoscope apparatus comprising: a temperature sensor provided in the vicinity of the image sensor; a temperature detection circuit for detecting that the temperature measured by the temperature sensor is equal to or higher than a predetermined temperature; And a circuit for detecting that the temperature measured by the temperature sensor is equal to or higher than a predetermined temperature, and reducing the amount of illumination light entering the light guide from the light source lamp. Mirror device.