JPH03153208A - Dimming device for endoscope - Google Patents

Abstract

PURPOSE:To adjust the brightness of an image even outside a range wherein the quantity of light is adjustable by a stop, etc., by varying the charge storage time of a solid-state image pickup element outside the adjustable range of at least a light quantity adjusting means, and controlling the output level of the solid-state image pickup element. CONSTITUTION:When the stop 23 reaches the limit of operation, a switching circuit 36 sends the output of a differential circuit 34 to a solid-state image pickup element driving circuit 31 according to the information from the stop 23. Consequently, the set value of a set value generating circuit 35 and the output of a brightness detecting circuit 33 are inputted to the differential circuit 34 and their difference is sent to the solid-state image pickup element driving circuit 31 through the switching circuit 36. Then the solid-state image pickup element driving circuit 31 which controls the charge storage time of the solid- state image pickup element 20 to perform automatic dimming operation so that the brightness of the screen become constant. Consequently, the brightness of an image can be adjusted even outside the range wherein the quantity of light is adjustable by the stop 23, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light control device for an endoscope that controls the brightness of an internal mirror image captured using a solid-state image sensor.

[Prior Art] In recent years, it has become possible to observe organs within a body cavity by inserting an elongated insertion section into a body cavity, and to perform various therapeutic procedures as needed using a treatment instrument inserted into a treatment instrument channel. Endoscopes are widely used.

Furthermore, an endoscope apparatus has been developed that uses a solid-state 1111i1 element such as a charge-coupled device (COD) to capture an image of an endoscope and display it as a video image.

In such an endoscopic II device, automatic light control is performed, for example, by adjusting the amount of illumination light so that the brightness of the screen is constant. Lighting light this 21! I adjustment is, for example, JP-A-61
As shown in Japanese Patent No. 37226, this is usually done using only the diaphragm of the light source.

[Problems to be Solved by the Invention] However, when adjusting the illumination light G only by using the aperture of the light source, if the distance from the subject is too short, the amount of light will not be sufficient even when the aperture is wide open, making it impossible to perform appropriate image evaluation. Also,
On the other hand, if the distance to the subject is too close, the aperture will reach its limit and too much light 2 will be emitted. When a solid-state I1m element is used, if the amount of light incident on the photodetector on the imaging surface is too large, an excessive amount of current (electronic current) leaks to the surrounding area, causing blurring on the screen and a blooming phenomenon, causing the image of that area to be distorted. will no longer be played faithfully.

The present invention has been made in view of the above circumstances, and provides a light control device for an endoscope that is capable of adjusting the brightness of an image outside the range in which tip adjustment using an aperture or the like is possible. is [1 target].

[Means for Solving the Problems] A light control device for an endoscope according to the present invention includes: a light amount adjusting means capable of adjusting the light emission incident on a solid image 1lii which enlivens a mirror image; and an AT element on the solid body. A prisoner image element driving means capable of variably controlling the charge #Z m u,'i;
using the a adjustment f stage and the solid state f%l cumulative driving means,
At least outside the adjustable range of the light constant adjustment means, the solid-state camera 8
and control means for controlling the output level of one tea.

[Function] In the present invention, within the range w4 of the light amount adjustment means, at least the light amount adjustment means does not affect the solid-state positive image element. 1)1
The output level of the solid-state imaging device is controlled by adjusting the light M, and when the output level is outside the adjustable range of the light adjusting means, the solid-state imaging atom driving means
Solid YQ I'a by changing the darkness against vJ accumulation
The output level of m is controlled m+.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

Figures 1 to 3 relate to the first embodiment of the present invention.
FIG. Figure 3 is a side view of the entire neck of the endoscope.

As shown in Fig. 3, the endoscope-made bean G
, l, is equipped with an electronic endoscope 1. This electronic endoscope 111
has an elongated, for example, flexible insertion section 2, and a large-diameter operating section 3 is connected to the rear end of the insertion section 2. A flexible universal cord 4 extends laterally from the rear end of the operating section 3, and a 11-bar connector 5 is provided at the tip of the 1-bar cord 4. This connector 5 is connected to a light source device 6. A signal cable 7 is extended from the 2'1 connector 5, and a signal connector 8 provided at the end of the signal cable 7 is connected to a camera unit unit (hereinafter referred to as CCU) 9. It is now possible to do so. Furthermore, in the CCU 9,
A monitor 10 is connected.

A hard distal end portion 11 is provided on the distal end side of the front insertion portion 2, and a bendable curved portion 12 is provided on the rear side adjacent to the distal end portion 11. Further, the operating section 3 is provided with a bending operation knob 13, and by rotating the bending operation knob 13, the bending section 12 can be bent vertically/horizontally. In addition, the operation section 3
is provided with an insertion [J14] that communicates with the neck shell V channel provided in the insertion portion 2.

As shown in FIG. 1, a light guide 16 for transmitting illumination light is inserted into the entry section 2 of the electronic endoscope 1. The distal end surface of the light guide 16 faces a light distribution lens 17 disposed at the distal end portion 11 of the insertion section 2, so that illumination light can be irradiated onto the subject 18 through the light distribution lens 17. Also, the input m of the lie 1 to guide 16 is
The OH side is inserted through the universal cord 4 and connected to the connector 5. Further, the tip portion 11 is provided with an objective lens system 19, and a solid-state image sensor 20 such as a COD is disposed at the imaging position of the objective lens system 19. Note that when a simultaneous imaging method is used, a color mosaic filter is provided in front of the solid-state imaging device 20. The signal line connected to the solid-state imaging device 20 is connected to the front insertion portion 2. Universal code 4. The signal cable 7 is inserted through the signal cable 7 and connected to the signal connector 8 .

On the other hand, an illumination lamp 21 is installed in the light source device 6.
), the light emitted from the lamp 21 is made into parallel light by the anti-oA mirror 22, passes through the aperture 23, is condensed by the condenser lens 24, and enters the incident end of the light guide 16. There is. Further, the aperture 23 is driven by an aperture drive circuit 25. This aperture drive circuit No. 25 is designed to prevent the aperture 23 from hanging in response to an input signal.

Further, a solid-state image sensor driving circuit 31 for driving the solid-state image sensor 20 is provided in the CCUQ. The image element driving circuit 31 is mounted on this solid state, for example, in Japanese Patent Laid-Open No. 63-3
As described in Japanese Patent No. 14980, signal charges are accumulated after the unnecessary charges are swept away by fast readout, and the solid-state image sensor 20 is driven by the signal charges in a manner similar to the readout, and the unnecessary charges are discarded. By changing the period, it is possible to change the accumulation time of the electric charge. The period during which the unnecessary charges are swept away can be changed according to the input signal to the solid-state image sensor driving circuit 31.

The signal>3 driven by the solid-state image sensor driving circuit 31 and read out from the solid-state image sensor 20 is input to the A3 processing circuit 32 and the FP degree detection circuit 33 in the CCUQ. . The signal processing circuit 32 performs video signal processing on the output signal of the solid-state image sensor 2o, and outputs the video signal to the monitor 10. A subject image is displayed on this monitor 1o. On the other hand, the brightness detection circuit 33 is configured to detect the brightness level of the output signal of the solid state f1@element 2o.

The output of this brightness detection circuit 33 is applied to the −/- side input terminal of the differential circuit 34. Also, Fu E]
The brightness setting value is generated by input from the front panel, etc.
A set value generation circuit 35 is provided, and the output J of this set value generation circuit 35 is applied to the other input terminal of the differential circuit 34. teeth,
Find the difference between the two inputs, and the difference is the switching circuit 36.
/, 1 so that it is input to . The switching circuit 36 selectively sends the output of the differential circuit 34 to either the aperture drive circuit 25 or the solid-state image sensor drive circuit 31 based on information from the comparison 23 of the light source device 6. There is.

Next, the operation of this embodiment will be explained with reference to FIG.

In this embodiment, automatic dimming is performed on both the light source device 6 side and the CCLJ 9 side, and basically the dimming is performed by the aperture 23 on the light source device 6 side, and the dimming is disabled in the aperture 23 on the light source device 6 side. Within a possible range, by controlling the charge accumulation time of the solid-state image sensor 20 on the CCUQ side, the brightness of the screen can be adjusted to keep it constant.

Information on the state of the diaphragm 23 is sent from the aperture 23 in the light source device 6 to the switching 36 in the CCU 9. When the switching circuit 36 has not reached its operating limit, the switching circuit 36
sends the output of the differential circuit 34 to the aperture drive circuit 25. As a result, the set value (optimal light R
level) and the output of the brightness detection circuit 33, that is, the level of the amount of light actually incident on the solid-state image sensor 20, to the differential circuit 3.
4 is taken in, and the difference is sent to the aperture drive circuit 25 via the switching circuit 36. Then, the diaphragm 23 is driven by the diaphragm drive circuit 25, the amount of light emitted from the illumination lamp 21 is adjusted, and the brightness of the screen is automatically adjusted so as to be constant.

On the other hand, when the aperture 23 reaches its operating limit, the switching circuit 36 sends the output of the differential circuit 34 to the solid-state image sensor drive circuit 31 based on information from the aperture 23. This results in
The differential circuit 34 takes in the set value generated by the set value generation circuit 35 and the output of the brightness detection circuit 33, and the difference between A and A is sent to the solid-state image sensor drive circuit 31 via the switching circuit 36. The solid-state image sensor driving circuit 31 controls the charge accumulation time of the solid-state image sensor 20, and automatically adjusts the brightness of the screen to be constant. Zunawara, aperture 2
3 is fully apertured, that is, when the amount of light received by the solid-state image sensor 2o is too large, the time for the charge accumulation operation is shortened.

This reduces the exposure ω of the solid-state image sensor 20. On the other hand, when the capacitor 23 is fully opened, that is, when the solid-state image pickup device 20 does not receive enough data, the time for charge storage f+lJ is lengthened. This increases the amount of exposure of the solid-state image sensor 20. In this way, the output from the solid-state B image element 2O is maintained at a constant level.

FIG. 2 shows the relationship between the distance to the subject and the brightness on the screen. The solid line indicates dimming with only the diaphragm (before the countermeasures), and the broken line indicates the solid lead 2
A case is shown in which 01 is used for dimming by charge accumulation time a-control of 0 (after countermeasures). As shown in this figure, before countermeasures,
In either case after the countermeasures are taken, in the aperture operable range, the light source device F? The diaphragm 23 in 6 maintains the optimum light amount. -h, outside the diaphragm operable range, before the measures, after the diaphragm 23 is fully closed and after it is fully opened, the if on the screen is
While the power is out of the optimum light amount, after vA it is comparatively 23
Even after the lens is fully stopped down and fully opened, the amount of light on the screen is maintained at the optimum level.

As described above, according to the present embodiment, the brightness of the image is automatically adjusted to always be 1i1 even outside the range where the amount of light can be adjusted by the diaphragm 23.

4 and 5 relate to the second embodiment of the present invention, FIG. 4 is an explanatory diagram showing the configuration of the endoscope system 2, and FIG. 5 is a characteristic diagram showing the relationship between the distance to the subject and the brightness. It is.

In this embodiment, a CPtJ 41 is provided in place of the differential circuit 34 and switching circuit 36 of the first embodiment.

The output of the brightness detection circuit 33 and the output of the set value generation circuit 35 are input to the CPU 41 manually.

Moreover, the output of this CI) U 41 is transmitted to the aperture drive circuit 2.
5 and is input to the solid-state imager driving circuit 31. Further, information on the state of the aperture 23 is inputted to the CPU 41 manually.

In the first embodiment, the timing for performing dimming on the CCU 9 side was after the diaphragm 23 on the light source Vt2'f6 side reached its operating limit, but in this embodiment, the timing from the light source product 6 side to the CCUQ side is For the purpose of smoothly transferring the light control means to the light source device 6.
From a little before the side aperture 23 reaches the initial limit, CCt
The JQ side also controls the light.

However, as shown by diagonal lines in Fig. 5, the comparison 23
In the region from just before reaching the operating limit to up to the operating limit, the CPLJ41 is equal to the set value by the set value generating circuit 35 and lli! Based on the difference in A, both the diaphragm drive circuit 25 and the solid-state 1 cm magnification drive circuit 31 are simultaneously controlled by the two dimming means to simultaneously adjust the light.

In other areas, the CPtJ 41 takes in the setting value from the setting f1 generation circuit 35 and the output from the brightness detection circuit 33, and based on the difference therebetween, the CPtJ 41 determines whether the CPtJ 41 is in the area inside the shaded area, that is, within the diaphragm operable range. The diaphragm drive circuit 25 is dimmed by &lI Ill L, and the solid-state image pickup device drive circuit 31 is controlled to perform dimming in the area outside the shaded area, that is, outside the diaphragm operable range.

According to this embodiment, there is a smooth transition between two states: dimming using the shifter 23 and dimming using u control of the charge IB product time of the solid-state dancer 20.

Other configurations, fi uses, and effects are the same as in the first embodiment.

FIG. 6 is a characteristic diagram showing the relationship between the distance to the subject and the brightness in the third embodiment of the present invention.

The configuration of this embodiment is similar to that of the second embodiment, but CPL
The dynamics of I41 are different.

That is, in the second embodiment, the light source device f! Adjust the light on the CCUQ side a little before the aperture on the i6 side reaches its limit.
However, in this embodiment, dimming is always performed on the light source device 6 side and the CCUQ side at the same time. in this case,
As in the second embodiment, simultaneous dimming is performed under the control of the CPU 41, but as shown by diagonal lines in FIG.
Light control is performed mainly on the light source device side 6, and the CCUQ side performs an operation to supplement the light control on the light source device 6 side. For example, the light source device 6
When a time delay occurs when performing the aperture operation on the CCUQ side, the CCUQ side adjusts the CCU to cover the time delay.
Make sure that dimming is performed on the CUQ side. Incidentally, in the area J outside the shaded area, that is, outside the range in which the diaphragm can operate, the light cannot be adjusted by the diaphragm 23, so the light is adjusted by controlling the charge accumulation time of the solid-state imager 20.

The other functions and effects of the configuration 0 are the same as those of the first or second embodiment.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and for example, the adjusting means is not limited to the aperture provided in the light source device, but may also be provided in the aperture for adjusting the light amount of the lamp or in the observation optical system. It may also be a squeeze or the like.

Further, the light source device δ6 and the CCU 9 may be integrated.

In addition, the endoscope to which the present invention is applied has a solid MaM at the tip.
Either the A type that takes the right direction, or the B type that guides the image to the outside of the VQ object via an image guide using an optical fiber and then captures the image with the Odorizo Seiko is fine. Further, the imaging method may be a simultaneous method or a b-plane sequential method. Also,
The present invention can be applied to both medical and industrial endoscopes.

[Effect of Te brightness] As explained above, according to the present invention, at least C outside the adjustable range of the lower stage of light amount adjustment is caused by the charge accumulation 1 of the solid-state image sensor.
Since the output level of the solid-state Vi image element is controlled by changing the 15 darkness, there is an effect that the brightness of the 5 images can be adjusted outside the range where the light ffi can be adjusted using an aperture or the like.

[Brief explanation of the drawing]

Figures 1 to 3 relate to the first embodiment of the present invention.
The figure shows the configuration of the endoscope device, Figure 2 is a characteristic diagram showing the relationship between the distance to the subject and the brightness, and Figure 3 is a side view showing the metal body of the endoscope device. 4 and 5 relate to a second embodiment of the present invention, and FIG. 4 shows the configuration of an endoscope device.
11 is a characteristic diagram showing the relationship between the distance to the subject and the brightness, and FIG. 6 is a characteristic diagram showing the relationship between the distance to the subject and the brightness according to the third embodiment of the present invention. 1... Electronics only $11 6... Light source equipment j19
...CCU 20...Solid Nine Image Soryo 23
...Comparison 25...Aperture drive circuit 31...
・Solid-state element image element driving circuit 36...Swipping circuit Figure 1 Figure 2 Figure 6 ccu@a source

Claims (1)

[Scope of Claims] Light amount adjustment means capable of adjusting the amount of light incident on a solid-state image sensor that captures an endoscopic image; solid-state image sensor driving means capable of variably controlling the charge accumulation time of the solid-state image sensor; and the light amount The output level of the solid-state image sensor is adjusted by using the adjustment means and the solid-state image sensor driving means, and by changing the charge accumulation time of the solid-state image sensor by the solid-state image sensor driving means at least outside the adjustable range of the light amount adjustment means. 1. A light control device for an endoscope, comprising a control means for controlling.