JPS6269222A - Endoscope recording device - Google Patents

Abstract

PURPOSE:To cover sufficiently variation in the quantity of light at an object position due to the depth of photographic distance by varying the distance between the optical axis of irradiation of an endoscope and the axis of rotation of a rotary shutter and controlling an irradiation time. CONSTITUTION:The shape of a shutter blade 6 is so designed, for example, as shown in a figure that the blade transmission time (corresponding to the peripheral length at each radial position of a shutter blade) of irradiated light from a light source lamp 3 is varied by utilizing the peripheral speed difference at each radial position when the rotary axis 7a of the shutter blade for a illumination light axis 0 shifts in position, namely, when the gap between both axis 0 and 7a varies. Namely, the respective positions on the radial line (cutoff reference line 7a) of the shutter blade 6, e.g. points (a), (b), and (c) are made different in circumferential length (irradiated light cutoff length) by varying the curvature of the outer edge 6b of the blade 6. Consequently, variation in the quantity of light between a close point and a distant point due to the large depth of an object position of observation (photography) is dealt with sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an endoscopic recording device for observing and recording the inside of a living body cavity or a mechanical device (hereinafter referred to as the inside of a living body cavity, etc.).

[Technical background and problems of the invention]

Generally, when observing the inside of a living body cavity using an endoscope, for example, on a television, etc., it is necessary to control the amount of illumination light irradiated to an appropriate amount depending on the brightness of the observation site (for example, the inside wall of the living body). There is. In this case, conventional control methods measure the light intensity (or brightness) of the entire image guide or a partial range, and ensure that the light intensity value from the target area during observation or shadowing falls within a predetermined range (middle limit). It is controlled using a method.

However, although the observation (photographing) site within the body cavity that is targeted by an endoscope is generally narrow in space, the distance from the tip of the endoscope scope to the target site is quite deep. Because it is deep, there are points located close to the tip of the scope (hereinafter referred to as periapsis) and points located relatively far away (hereinafter referred to as periapsis).
There is a significant difference in the amount of light (brightness) at that point (referred to as the far point). Therefore, in the case of observation or photography, the amount of irradiation light must be controlled depending on whether the target region is located at the near point or far point.

On the other hand, since there are target parts that move quickly in biological cavities, there is a risk of "blurring" of the image if the exposure time is increased, and therefore certain restrictions must be imposed from this perspective. become. Therefore, an irradiation method that satisfies both of the above-mentioned conditions for controlling the irradiation time of an endoscope has been expected, and its realization has been desired.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and is capable of sufficiently covering variations in the light intensity of the target region due to the depth of the photographing distance, and without causing "image blur" even in fast-moving target regions. The purpose of this study is to provide an endoscope recording device with a new irradiation method.

[Summary of the invention]

The outline of the present invention for achieving the above object is that the irradiation time is controlled by changing the distance between the irradiation optical axis of the endoscope and the rotation axis of the rotary shutter.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

In the block diagram of Fig. 1, ■ is a general endoscope scope, and its tip has an illumination light irradiation port means and a photographing (
An optical system for imaging (both not shown) is provided by appropriate means. 2 is a flexible light guide whose one end is connected to the illumination light irradiation port means in the scope 1; 3 is a light source of, for example, white light that is turned on in conjunction with the endoscope device when it is activated; a lamp; 4 is a condenser lens arranged to condense the illumination light from the lamp 3 onto the other end surface 2a of the light guide 2; 5 is an infrared cut filter inserted on the illumination optical axis O; 6 is a A rotary shutter shielding plate (hereinafter referred to as a shutter blade) fixed to the rotating shaft 7a of the motor 7 is provided so as to be movable integrally with the motor 7 with respect to the main body of the apparatus.

Note that the shape of this shutter blade will be described later.

8 is a screw for displacing the motor 7 in the direction of arrow A-A' (direction perpendicular to the illumination optical axis), and a gear 9 is fixed to one end of the screw.

10 and 11 are respective drive gears 10a.

This is a displacement drive motor for rotating the screw gear 9 (that is, the screw screw 8) in forward and reverse directions via the screw gear 11a, one of which is provided for forward rotation and the other for reverse rotation. In this case, in order to avoid mechanical interference between both motors during normal rotation and reverse rotation, an appropriate one-way rotation transmission clutch (Fig. (not shown) shall be provided. It goes without saying that if a reversible motor is used, both motors 10 and 11 can be replaced with one motor.

Reference numeral 12 denotes an image sensor (for example, C
A video processor that performs image processing based on electrical signals from the image sensor (0D), and has a function that can also detect the optimum light amount of the target area based on the signal from the image sensor, and further includes a function to detect the optimum light amount signal of the target region. It is configured in advance so that a light amount control signal and a video frame rate signal can be outputted to a motor control circuit I3, which will be described later. The cough motor control circuit 13 receives these signals and controls the three motors 7 and 1.
This is a circuit for controlling the operation of the shutter blade motor 7, which synchronizes the rotation period of the shutter blade motor 7 with the video frame rate by receiving the video frame rate signal from the video processor 12, and controls the drive motor based on the light amount control signal. 10.11 is used to control the amount of rotation. 14
is a display device connected to the video processor 12.

Thus, the shape of the shutter blade 6 changes when the position of the shutter blade rotation axis 7a with respect to the illumination optical axis O changes.
That is, when the distance between the two wheels 0.7a changes, by utilizing the difference in circumferential speed at each radial position of the shirt blade 60, the transmission time of the illumination light from the light source lamp 3 (circle at each position) can be changed. For example, it is designed to have a shape as shown in FIG. 2 so that the length (corresponding to the length on the circumference) can be changed. That is, in FIG. 2, each portion of the shafter blade 6 on the radial direction line (shielding reference line 6a), for example a
The curvature of the outer edge 6b of the blade 6 is changed so that the circumferential lengths (illumination light shielding lengths) at point, point b, and point 0 are different from each other. That is, R=r...Radius r2 from the rotation axis 7a on the shield reference line 6a to the 0 point...Rotation axis 7a to b on the shield reference line 6a
Radius r to the point, ... a from the rotation axis 7a on the shielding reference line 6a
Radius to the point ro... Minimum radius r from the rotation axis 7a... Distance from the rotation axis 7a to the outer edge of the shutter blade 6b when the shielding reference line 6a is rotated counterclockwise by an angle θ0 , each of the points a, b, and c is formed so as to satisfy the expression -r0. Therefore, each point a
, b, and c are different from each other as shown in FIG.

Now, when the scope 1 is inserted into the body cavity and the light source lamp 3 is turned on, the illumination light from there is irradiated from the tip of the scope 1 toward the target area via the filter 5, condenser lens 4, and light guide 2. . Then, the reflected light (image light) from the target area enters the image sensor in the scope 1,
The signal from the element is converted into a video signal within the video processor 12, and reaches the display device 14, where it is displayed as an image.

At this time, the shutter blade 6 is rotating at a constant angular velocity in synchronization with the video frame rate, but since the light amount control signal from the video processor 12 is sent to the motor control circuit 13, the drive motors 10 and 11 rotate. In order to change the illumination light shielding length (that is, exposure time) at the 0 position of the illumination optical axis of the shutter blade 6 to a length suitable for the light amount control signal from the video processor 12 (the optimum exposure time), Shift the position of the blade 6 relative to 0. As a result, the intensity of the light source lamp 3 is kept constant, the angular velocity of the shutter blade 6, which rotates in synchronization with the video frame rate, is kept constant, and the blade aperture as seen in conventional cine cameras can be maintained constant. The exposure time of the rotary shutter can be set to the optimum state without changing the angle.

In the case of an endoscope, the exposure time is the illumination light irradiation time, so if the target region is originally at a far point where the amount of light is low, the irradiation time (exposure time) will naturally become longer. Therefore, although it is generally thought that "image blur" is likely to occur, there is no need to worry about "image blur" because the movement at the far point is theoretically smaller than that at the near point.

Here, the shape of the shutter blade 6 is not limited to the radius-decreasing type shown in FIG. 2, but may be an axially symmetrical shape as shown in FIG. 4. In this case, unlike the one shown in the second diagram, the exposure aperture 6c is set to have the same aperture width at each point a, b, and c, so the exposure (irradiation) time depends on the circumferential velocity at each point. It will be decided. Further, since uneven rotation of the shutter blade 6 directly affects the accuracy of the rotary shutter, it is necessary to consider means for maintaining a good rotational balance of the blade itself. For example, the second
In the case of a blade having an asymmetrical shape with respect to the rotating shaft 7a as shown in the figure, the center of gravity of the blade itself can be adjusted by changing the thickness of each part of the blade, or by attaching a counterweight part to the side where the mass is insufficient. It is necessary to design the position so that it is located on the rotation axis 7a. In this respect, the device shown in FIG. 4 has the advantage that since the rotation centers and the centers of gravity are coincident, the design as described above is not required and the device is simple.

It should be noted that the illustrated embodiment is just one example, and the present invention is not limited thereto, and it goes without saying that various modifications can be made without departing from the gist of the invention. .

〔Effect of the invention〕

As described above, when using the present invention, it is possible to sufficiently cope with changes in light intensity between the near point and the far point that occur due to the depth of the observation (photographing) target region, and to cope with rapid movement of the target region. Therefore, it is possible to obtain an endoscope recording device that does not cause "image blur" even when the image is blurred.

Furthermore, when the present invention is implemented in the form shown in the illustrated embodiment, exposure (irradiation) control can be performed while keeping the lamp intensity constant and in a constantly lit state, which reduces the durability of the device and the life of the lamp. can be held for a long time.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a shape diagram of a shutter blade, and Fig. 3 is irradiation (exposure) time at each point of the shutter blade that rotates in synchronization with a video frame rate signal. FIG. 4 is a shape diagram showing another embodiment of the shutter blade. ■...Scope, 2...Light guide, 3...Light source lamp, 6...Shutter blade, 7...Motor, 10.11...Drive motor, 12...Video processor, 13 ...Motor control circuit, 14...Display device Fig. 1

Claims (3)

[Claims] (1) An endoscope recording device characterized in that the irradiation time is controlled by changing the distance between the irradiation optical axis of the endoscope and the rotation axis of the rotary shutter. (2) The endoscope recording device according to claim 1, wherein the center of gravity of the rotation shielding plate of the rotary shutter is aligned with the rotation axis of the rotary shutter. (3) The endoscope recording device according to claim 2, wherein the rotation shielding plate of the rotary shutter is formed axially symmetrically with respect to the rotation axis of the rotary shutter.