JPH0545592A - External tv caera device for endoscope - Google Patents

Abstract

PURPOSE:To obtain the external TV camera device for the endoscope which has wide depth of field in combination with a hard endoscope which uses a relay lens. CONSTITUTION:An integrator 22 integrates and converts an image pickup signal, which is obtained by the photoelectric conversion of an image pickup element 19, into a DC signal to generate a control signal for dimming and the output of this integrator 22 is supplied to one input terminal of a differential amplifier 24, whose other input terminal is connected to a reference voltage 25. This reference voltage 25 is the command of control over the quantity of illumination light and the quantity of reflected light and the output of the differential amplifier 24 is sent to a stop blade control reversible motor 17 of a light source device 8 and a stop device 20 in a camera head 2 through switches 26 and 27; and the reversible motor 17 for stop blade control is rotated to control the quantity of illumination light by a stop blade 16 and also control the opening quantity of the stop device 20, thereby nearly equalizing the output of the integrator 22 to the reference voltage 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external TV camera device for an endoscope which is detachably attached to an eyepiece portion of the endoscope.

[0002]

2. Description of the Related Art In recent years, endoscopes have been widely used for diagnosis, observation, treatment, etc. in body cavities, and in the inspection scene of endoscopes, observation is performed with high resolution over the entire region from the near point to the far point. It is strongly desired to be possible.

Generally, the subject cannot maintain a perfect focus from a far point to a near point by an index called a subject depth which is a theoretical limit of an optical lens, but the subject is focused within a permissible scattering circle.

In a rigid endoscope, which is a kind of endoscope and has a light receiving / transmitting means constituted by a relay lens instead of a fiberscope, the resolution does not depend on the number of fibers of the fiberscope, and therefore within the allowable scattering circle. By maintaining the in-focus state, it becomes possible to achieve high resolution.

[0005]

However, for example, in combination with a conventional three-plate camera for an endoscope, which can be expected to have high resolution, the depth of field is narrow, so that the high resolution characteristics of a rigid endoscope cannot be sufficiently exhibited. is the current situation.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an external TV camera device for an endoscope having a wide depth of field in combination with a rigid endoscope using a relay lens. Has a purpose.

[0007]

An external TV camera device for an endoscope according to the present invention comprises a diaphragm mechanism in the optical path of an image forming optical system to an image pickup device for picking up an observation image.

[0008]

[Operation] The amount of incident light is controlled by the diaphragm mechanism, and the observation light from the endoscope is focused on the end surface of the image pickup device.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 relate to an embodiment of the present invention, FIG. 1 is an explanatory view for explaining the constitution and operation of an external TV camera device for an endoscope, and FIG. 2 is a constitution showing the constitution of diaphragm blades. 3 and 4 are explanatory views for explaining the diaphragm mechanism of the diaphragm device.

As shown in FIG. 1, an external TV camera device 1 for an endoscope includes a camera head portion 2 and an image pickup signal processing device 3.
The camera head portion 2 is inserted into the body cavity and the image of the subject 4 in the body cavity is transmitted. For example, the camera head portion 2 can be detachably attached to the eyepiece portion 6 of the rigid endoscope 5. It has become.

The rigid endoscope 5 is, for example, a light guide (hereinafter, referred to as LG) that transmits illumination light from a light source device 8 that illuminates the subject 4 from an illumination lens 7 provided at the tip of the rigid endoscope 5. 9), an observation window 10 provided at the tip of the rigid endoscope 5 that receives reflected light that is an image of the subject 4, and the reflected light that has entered this observation window
And a plurality of relay lenses 12 for transmitting the reflected light to the eyepiece section 6 by means of an eyepiece lens 13.
The reflected light is guided to the base end surface of the.

The light source device 8 includes, for example, a light source lamp 14 for supplying illumination light and a condenser lens 15 for converging the illumination light from the light source lamp 14 on the base end face of the LG 9. A diaphragm blade 16 for controlling the amount of illumination light from the light source lamp 14 incident on the LG9 base end surface is provided between the lens 15 and the LG9 base end surface, and as shown in FIG. Reversible motor 17 for blade control
By rotating the diaphragm blade 16 as indicated by the arrow, the light source lamp 14 incident on the LG9 base end surface is
It is possible to control the amount of illumination light from.

The camera head portion 2 mounted on the eyepiece portion 6 of the rigid endoscope 5 has an image pickup condenser lens 18 for collecting the reflected light guided to the base end surface of the eyepiece portion 6. And an image pickup device 19 for photoelectrically converting the reflected light condensed on the end face by the image pickup condenser lens 18, and the amount of reflected light between the image pickup condenser lens 18 and the base end face of the eyepiece section 6. A diaphragm device 20 for adjusting and controlling the aperture is provided, and the diaphragm device 20 is composed of a diaphragm (iris) mechanism for expanding the depth of field as shown in FIG. The opening amount of the can be controlled.

The image pickup signal photoelectrically converted by the image pickup device 19 is transmitted to a processor 21 and an integrator 22 provided in the image pickup signal processing device 3, and the processor 2
1 is adapted to generate a video signal, for example, an NTSC signal or the like from an image pickup signal so that a subject image can be displayed on the observation monitor 23.

The integrator 22 integrates the image pickup signal photoelectrically converted by the image pickup device 19 and converts the image pickup signal into a DC signal to generate a control signal for dimming. The output of the integrator 22 is input to one of the differential amplifiers 24, and the other input of the differential amplifier 24 is connected to the reference voltage 25. Here, the reference voltage 25 is a target value for light amount control.

The switches 26 and 27 are designed to operate in conjunction with each other, and can be switched manually, for example.
If the switch 26 is on the SW26a side, the switch 27 is on the SW27a side, and similarly, the switch 26 is on the SW26a side.
If it is on the b side, the switch 27 is on the SW 27b side.

When SW26a and SW27a are selected, a predetermined voltage 28 is connected to SW27a, and for example, the opening 20a of the diaphragm device 20 is forcibly fixed to the open state based on this predetermined voltage 28. With
As described above, the reversible motor 17 for controlling the diaphragm blades is rotated by the output of the differential amplifier 24, and the diaphragm blades 1
By controlling the amount of illumination light by 6, the output of the integrator 22 becomes substantially equal to the reference voltage 25. The state at this time is called a normal mode.

When SW26b and SW27b are selected, the variable voltage 29 is connected to SW26b and the output of the differential amplifier 24 is connected to SW27b. By rotating the reversing motor 17 for diaphragm blade control by the variable voltage 29 and controlling the amount of illumination light by the diaphragm blade 16, the maximum amount of illumination light within a range where the LG 9 used for the rigid endoscope 5 does not burn. The output of the integrator 22 becomes substantially equal to the reference voltage 25 by adjusting the irradiation light amount and adjusting the opening amount of the opening 20a of the diaphragm device 20 by the output of the differential amplifier 24. The state at this time is called a wide subject depth mode (hereinafter, abbreviated as AF mode).

The diaphragm device 20 is not limited to the iris mechanism as described above, but may be a diaphragm mechanism provided in a general TV camera.

Although the diaphragm device 20 is arranged between the image pickup condenser lens 18 and the base end surface of the eyepiece section 6, the invention is not limited to this, and the amount of light incident on the image pickup device can be controlled. It may be arranged in the optical path of the imaging optical system to the image pickup device, and may be arranged, for example, between the incident surface of the camera head section 2 and the image pickup condensing lens 18.

An external TV for an endoscope constructed in this way
The operation of the camera device 1 will be described.

For example, the switch 2 of the image pickup signal processing device 3
The normal mode is set by 6 and 27. In this normal mode, the illumination light from the light source device is applied to the subject 4 via the LG 9, and the reflected light of the subject 4 is reflected by the plurality of relay lenses 1.
It is transmitted via 2 to the camera head unit 2 attached to the eyepiece unit 6. The transmitted reflected light passes through the opening 20a and the imaging condenser lens 18 in the open state, and then the imaging device 1
The light is condensed on the end surface of 9 and photoelectrically converted to obtain an image pickup signal. With this image pickup signal, the processor 21 generates a video signal and displays the increase of the subject on the observation monitor 23. The image pickup signal is also input to the integrator 22, and the diaphragm blade 16 is controlled by the differential amplifier 24 through the reversing motor 17 for diaphragm blade control so that the control signal integrated by the integrator 22 becomes equal to the reference voltage 25. By rotating the
The illumination light from the light source lamp 14 incident on the nine base end faces is controlled.

Also, for example, the AF mode is set by the switches 26 and 27 of the image pickup signal processing device 3. In this AF mode, the illumination light emitted from the light source device 8 by the variable voltage 29 has the maximum light amount, and the illumination light of this maximum light amount is emitted to the subject 4 via the LG 9 and the subject 4
The reflected light is transmitted to the camera head unit 2 mounted on the eyepiece unit 6 via the plurality of relay lenses 12. The transmitted reflected light is condensed on the end surface of the image pickup element 19 through the diaphragm device 20 and the image pickup condenser lens 18 and photoelectrically converted to obtain an image pickup signal. With this image pickup signal, the processor 21 generates a video signal and displays the subject image on the observation monitor 23. The image pickup signal is also input to the integrator 22, and the diaphragm device 20 is controlled by the differential amplifier 24 so that the control signal integrated by the integrator 22 becomes equal to the reference voltage 25.

The effect of the external TV camera device for an endoscope that operates in this way will be described.

In a general imaging optical lens system, the larger the aperture value (f value), the wider the depth of field. That is, if the light is incident on the image pickup optical system lens with sufficient brightness, the depth of field becomes wider by increasing the f value of the image pickup optical system (closing as much as possible).

Therefore, by irradiating the subject with the maximum amount of light and limiting the amount of incident light by the diaphragm device 20 based on the reference voltage 25, a wide subject depth having a high resolution can be obtained over the entire region from the near point to the far point. The result is the same as if the autofocus function were realized.

Further, depending on the type of the rigid endoscope to be combined, if the LG is always irradiated with the maximum amount of illumination light,
Even when LG is damaged by heat, it is possible to switch between the normal mode and the AF mode by the switches 26 and 27, and if necessary, a wide depth of field that has a high resolution over the entire area from the near point to the far point can be obtained. Obtainable.

[0029]

As described above, according to the present invention, the external TV camera device for an endoscope of the present invention can be used in combination with a rigid endoscope using a relay lens from a near point to a far point. There is an effect that it is possible to obtain a wide depth of field with a high resolution over the entire area.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a configuration and operation of an external TV camera device for an endoscope according to an embodiment.

FIG. 2 is a configuration diagram showing a configuration of diaphragm blades according to an embodiment.

FIG. 3 is an explanatory diagram illustrating a diaphragm mechanism of a diaphragm device according to an embodiment.

[Explanation of Codes] 1 ... External TV camera device for endoscope 2 ... Camera head part 3 ... Imaging signal processing device 19 ... Imaging device 20 ... Aperture device 21 ... Processor 22 ... Integrator 24 ... Differential amplifier 25 ... Reference Voltage 26 ... Switch 27 ... Switch

Claims (1)

[Claims] 1. An external TV camera device for an endoscope which is detachably attached to an eyepiece of an endoscope, comprising a diaphragm mechanism in an optical path of an image forming optical system to an image pickup device for picking up an observation image. An external TV camera device for an endoscope characterized by the above.