JP4864495B2 - Endoscope device with infrared cut filter - Google Patents

Description

  The present invention relates to an endoscope apparatus that observes an affected area using a light source such as a lamp, and more particularly to an infrared cut filter provided around a light source.

  In the endoscope apparatus, in order to illuminate an observation site such as a body cavity, light emitted from the lamp is guided to the distal end of the scope by a light guide provided in the scope and emitted from the distal end of the scope. In order to improve the color reproducibility of the observed image by eliminating long-wavelength light (infrared rays) other than visible light contained in the lamp light, or the observation site is affected by heat due to the infrared component having a heating action. In order to prevent this, an infrared cut filter is provided between the lamp and the light guide.

If the infrared cut filter is damaged by direct irradiation of illumination light, an infrared component is applied to the observation site, which may adversely affect the scope tip and the observation site. Therefore, for example, an ultraviolet cut filter is disposed between the infrared cut filter and the light source to prevent damage to the infrared cut filter (see Patent Document 1).
Japanese Patent Laid-Open No. 5-232387

  The infrared cut filter may be damaged by causes other than heat, such as external impacts. If the operator does not notice the damage to the infrared cut filter and continues endoscopic work such as surgery, the tip of the scope including the image sensor The effect of heat occurs on the part and the observation site.

  An endoscope apparatus according to the present invention is an endoscope apparatus that is safe for a subject against damage to an infrared cut filter and prevents a failure of the apparatus. A light source that emits illumination light and a light source are driven. A light source driving unit, an infrared cut filter arranged in the optical path of the illumination light and blocking light in the long wavelength region, a light shielding plate, an aperture for adjusting the amount of illumination light, and the brightness of the subject image are appropriate In order to maintain the brightness, an aperture driving unit is provided that drives the aperture to place the light shielding plate in the optical path. A conductor pattern is provided in the infrared cut filter, and light from the light source passes through the infrared cut filter having the conductor pattern. For example, a conductive pattern may be formed on the infrared cut filter by depositing a conductive film.

  As a configuration of the diaphragm, for example, a light-shielding plate is provided at the end, and a diaphragm that rotates the support portion that supports the light-shielding plate may be used. The optical path of the light traveling toward the distal end of the scope is partially The diaphragm rotates so as to shield it. In this case, the diaphragm driving unit rotates the diaphragm. As the configuration of the diaphragm driving unit, an actuator for driving a diaphragm such as a motor and an actuator driving unit for driving the actuator are provided. The infrared cut filter may be disposed between the diaphragm and the light source.

  The endoscope apparatus of the present invention includes pattern disconnection detection means for detecting disconnection of a conductor pattern. When the infrared cut filter is damaged due to external impact or the like, the conductor pattern is disconnected accordingly. Further, in the present invention, the aperture driving unit positions the aperture to the emergency position when the disconnection of the conductor pattern is detected by the pattern disconnection detecting means. Here, the emergency position is a position that does not give the influence of heat to the observation site, and represents a position where the amount of illumination light is reduced. The position where the light shielding plate is slightly deviated from the position where the illumination light is completely blocked, and the position where the light amount necessary for observation or the amount close thereto is preferably provided. For example, the diaphragm may be driven so that the light quantity is about 10% or 20% of the maximum light quantity that can be transmitted to the observation site of the illumination light.

  In the endoscope apparatus of the present invention, when the conductor pattern is disconnected, the observation site is illuminated with the minimum necessary illumination light, while the illumination light including light in the long wavelength region is slightly transmitted to the scope tip and the observation site. It does not cause thermal problems. Further, since the illumination light is not completely blocked, the observation site can be confirmed during the endoscopic work, and the necessary endoscopic work such as removal from the body of the scope can be performed even when the infrared cut filter is damaged.

  In order to reduce the amount of light as much as possible, it is preferable to provide a light amount reducing means for controlling the light source to reduce the light amount of the illumination light when the disconnection of the conductor pattern is detected by the pattern disconnection detecting means. In order to ensure effective switching between normal observation and when the infrared cut filter is damaged, the aperture drive unit relates to the brightness signal related to the brightness of the subject image and the aperture position for moving the aperture to the emergency position. It is preferable to provide a switching circuit to which a position signal is input. The switching circuit outputs a brightness signal when the conductor pattern is not disconnected, and outputs a position signal corresponding to the emergency position when the conductor pattern is disconnected. The diaphragm driving unit drives the diaphragm based on the brightness signal or the position signal.

  The endoscope light control device of the present invention has a light shielding plate, and a diaphragm for adjusting the amount of illumination light emitted from the light source, and a diaphragm for maintaining the brightness of the subject image at an appropriate brightness. An aperture driving unit that drives and places the light shielding plate in the optical path of the illumination light, an infrared cut filter that has a conductor pattern and is disposed in the optical path of the illumination light, and a pattern disconnection detection unit that detects disconnection of the conductor pattern The diaphragm driving unit positions the diaphragm to an emergency position where the influence of heat is not exerted on the observation site and the amount of illumination light is reduced when the disconnection of the conductor pattern is detected by the pattern disconnection detecting means. It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, when an infrared cut filter is damaged, it can respond safely, without having a bad influence on a test subject and an endoscope apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of an electronic endoscope apparatus according to the first embodiment.

  The electronic endoscope apparatus includes a video scope 10 and a processor 20, and the video scope 10 is detachably connected to the processor 20. The processor 20 is connected with a monitor 60 and a keyboard (not shown).

  The processor 20 is provided with a lamp 22 that emits white light, such as a halogen lamp or a xenon lamp, and a lamp power source 23 drives the lamp 22 to light. The illumination light emitted from the lamp 22 is incident on the incident end 12 </ b> A of the light guide 12 via the infrared cut filter 25 and the condenser lens 27. The light guide 12 that is an optical fiber bundle guides light from the lamp 22 to the distal end portion of the video scope 10, and the light emitted from the light guide 12 exits from the distal end portion of the scope via the light distribution lens 14. Thereby, illumination light is irradiated to the subject.

  The light reflected by the subject irradiated with the illumination light reaches the light receiving surface of the CCD 17 through the objective lens 15, and a subject image is formed on the light receiving surface of the CCD 17. A complementary color mosaic filter (not shown) is disposed in front of the CCD 17 corresponding to each pixel, and an analog image signal corresponding to the subject image is photoelectrically converted based on the light passing through the filter of each color element. appear. The image signals are sequentially read out one field at a time interval (here, 1/60 seconds) in accordance with a TV standard such as the NTSC system and sent to the video signal processing circuit 30 of the processor 20. The CCD 17 is driven by an image sensor driving circuit 31 of the processor 20.

  The video signal processing circuit 30 amplifies and digitizes the analog image signal and performs various signal processing such as white balance adjustment and gamma correction to generate a video signal such as an NTSC signal. Is done. The video signal is sent to the monitor 60, whereby the color observation image is displayed on the monitor 60 as a moving image. The video signal output from the video signal processing circuit 30 is sequentially sent to the dimming circuit 28.

  The system control circuit 33 including the timing controller 32 controls the operation of the processor 20 and outputs a control signal to the lamp power source 23. The timing controller 32 outputs a clock pulse signal for adjusting the timing of signal processing to the image sensor driving circuit 31 and the like. The light control circuit 28 is configured by a DSP (Digital Signal Processor) and outputs a control signal to the motor 24. The dimming circuit 28 sequentially detects luminance values indicating the brightness of the subject image based on video signals sent at 1/60 second intervals. Then, a difference between the actual luminance value of the subject image and the reference luminance value is detected, and a control signal is output to the motor 24 in accordance with the luminance level difference. The reference luminance value indicates the appropriate brightness of the subject image, and is set in advance by the operator through a keyboard operation or the like.

  The diaphragm 26 provided between the infrared cut filter 25 and the condensing lens can be rotated about the axis of the motor 24 so that the brightness of the subject image is maintained at an appropriate brightness. Then, the diaphragm 26 is rotated based on the control signal.

  FIG. 2 is a diagram showing the infrared cut filter 25. FIG. 3 is a diagram showing the spectral transmission characteristics of the infrared cut filter 25.

  A conductive film 25CP serving as a conductor pattern is formed on the surface 25S of the infrared cut filter 25 by vapor deposition, and connection portions 25PT are provided at both ends. Both ends of the connection portion 25PT are connected to a detection circuit (not shown here) for detecting disconnection provided in the dimming circuit 28. The infrared cut filter 25 is disposed in the optical path of the illumination light of the lamp 22, and the light emitted from the lamp 22 passes through the surface 25S on which the conductive film 25CP is formed and enters the light guide 12. As shown in FIG. 3, the infrared cut filter 25 here blocks light having a wavelength of 700 nm or more, that is, infrared rays (including light in the near infrared region).

  FIG. 4 is a control block diagram of automatic light control processing.

  A luminance difference signal, which is the difference between the preset reference luminance value and the luminance value detected by the luminance signal detector 28S, is sent to the drive unit 28T via the switch 28A. In the drive unit 28T, a drive signal corresponding to the luminance level difference is output to the motor 24. The motor 24 rotates by a predetermined amount in accordance with the drive signal, and thereby the diaphragm 26 rotates on its axis. In a state where the infrared cut filter 25 is not damaged, the switch 28A is switched so that the luminance level difference signal is sent to the drive unit 28T.

  The conductive film 25CP of the infrared cut filter 25 is connected to the detection circuit 28B, and the detection circuit 28B detects disconnection of the conductive film 25CP. When detecting the disconnection of the conductive film 25CP, the detection circuit 28B outputs a detection signal to the switch 28A and the system control circuit 33.

  A position detection circuit 28W such as a photo encoder detects the opening position of the diaphragm 26 by detecting the rotational position of the motor 24, and an opening degree difference signal indicating a difference from a preset opening degree for emergency use. Input to the switch 28A. When the detection signal is input to the switch 28A due to the breakage of the infrared cut filter 25, the switch 28A is switched so that the opening degree difference signal is sent to the drive unit 28T. The motor 24 rotates based on the drive difference signal, and the throttle 26 is positioned to the position of the emergency throttle opening by feedback control.

  Further, when the detection signal is input to the system control circuit 33, the control signal is output to the lamp power source 23. The lamp power supply 23 that has received this control signal outputs a drive signal to the lamp 22 so as to reduce the amount of illumination light.

  FIG. 5 shows the arrangement of the diaphragm 26.

  The diaphragm 26 has a light shielding plate 26 </ b> B at an end thereof, and is attached around the axis C of the motor 24. The diaphragm 26 is rotated by the rotation of the motor 24 and is movable in a range from the retracted position of the light beam LB of the light from the lamp 22 to the light shielding position where the light beam LB is completely blocked. The diaphragm 26 blocks the light beam LB, that is, a part of the optical path so that the brightness of the subject image displayed on the monitor 60 is maintained at an appropriate brightness.

  When the infrared cut filter 25 is damaged by applying an external force or the like to the electronic endoscope apparatus, the conductive film 25CP is disconnected and the switch 28A is switched. As a result, the diaphragm 26 rotates about the axis so that the light shielding plate 26B moves to the position (emergency position) shown in FIG. As shown in FIG. 5, the emergency position is a position where a part of the illumination light from the lamp 22 is input to the light guide 12A, but most of the illumination light is blocked by the light shielding plate 26B.

  As described above, according to the first embodiment, the infrared cut filter 25 is disposed between the diaphragm 26 and the lamp 22, and the conductive film 25 </ b> CP is formed on the surface 25 </ b> S of the infrared cut filter 25. When the conductive film 25CP is disconnected due to the breakage of the infrared cut filter 25, the diaphragm 26 moves so that the light shielding plate 26B of the diaphragm 26 is disposed at an emergency position that blocks most of the illumination light.

  The configuration of actuators such as a diaphragm and a motor may be other than the above-described embodiment. Moreover, you may provide a conductor pattern in an infrared cut filter other than vapor deposition of a electrically conductive film. Moreover, you may apply to the light source device for fiberscopes.

It is a block diagram of the electronic endoscope apparatus which is 1st Embodiment. It is the figure which showed the infrared cut filter. It is the figure which showed the spectral transmission characteristic of the infrared cut filter. It is a control block diagram of automatic light control processing. It is the figure which showed arrangement | positioning of an aperture_diaphragm | restriction.

Explanation of symbols

10 Videoscope 20 Processor 22 Lamp (light source)
23 Lamp power supply 24 Motor 25 Infrared cut filter 25CP Conductive film (conductor pattern)
26 Diaphragm 26B Shading plate 28 Dimming circuit 28A Switch (switching circuit)
28B detection circuit (pattern disconnection detection circuit)
33 System control circuit

Claims (7)

A light source that emits illumination light;
A diaphragm having a light shielding plate and adjusting the amount of illumination light;
An aperture drive unit that drives the aperture and arranges the light shielding plate in the optical path of the illumination light so as to maintain the brightness of the subject image at an appropriate brightness;
An infrared cut filter having a conductor pattern and disposed in the optical path of the illumination light;
A pattern disconnection detecting means for detecting disconnection of the conductor pattern,
When the break of the conductor pattern is detected by the pattern break detection means, the diaphragm drive unit moves the stop to an emergency position where the light amount is about 10% of the maximum light amount that can be transmitted to the observation site of the illumination light. An endoscope apparatus characterized by positioning.   2. The endoscope according to claim 1, further comprising a light amount reducing unit configured to control the light source to reduce a light amount of illumination light when a break in the conductor pattern is detected by the pattern disconnection detecting unit. apparatus. The infrared cut filter has a conductive film;
The endoscope apparatus according to claim 1, wherein the conductive pattern is formed as the conductive film.   The endoscope apparatus according to claim 1, wherein the diaphragm is provided with the light shielding plate at an end thereof and is rotatable about an axis.   The endoscope apparatus according to claim 1, wherein the infrared cut filter is disposed between the diaphragm and the light source. The aperture drive unit has a switching circuit to which a brightness signal related to the brightness of the subject image and a position signal related to the aperture position for moving the aperture to the emergency position are input;
The switching circuit is
In a state where the conductor pattern is not disconnected, a brightness signal is output,
The endoscope apparatus according to claim 1, wherein when the conductor pattern is disconnected, a position signal corresponding to the emergency position is output. A diaphragm having a light shielding plate and adjusting the amount of illumination light emitted from the light source;
An aperture drive unit that drives the aperture and arranges the light shielding plate in the optical path of the illumination light so as to maintain the brightness of the subject image at an appropriate brightness;
An infrared cut filter having a conductor pattern and disposed in the optical path of the illumination light;
A pattern disconnection detecting means for detecting disconnection of the conductor pattern,
When the disconnection of the conductor pattern is detected by the pattern disconnection detection means, the aperture driving unit moves the aperture to an emergency position where the light amount is about 20% of the maximum light amount that can be transmitted to the observation site of the illumination light. A dimming device for an endoscope characterized by positioning.

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