JPH0474687B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an automatic light control device for an endoscope that allows dimming to be adjusted to an illumination intensity suitable for observation.

[Technical background of the invention and its problems] In recent years, endoscopes that use solid-state imaging devices to display images of objects on display devices such as cathode ray tubes have been realized.

The electronic endoscope using the above-mentioned solid-state image sensor is
Compared to a system that forms an optical image on an image guide fiber, it is easier to record images and has the advantage that it can be made more compact in the future as highly integrated technology progresses.

However, when using the above solid-state image sensor,
If the amount of light incident on the photodetector on the imaging surface is too large, excessive charge leaks to the surrounding area, causing blurring and a blooming phenomenon on the playback screen, making it impossible to faithfully reproduce the image in that area, and causing the image to appear in the normal state. There is a problem that imaging becomes impossible until the state returns to normal.

There are devices that allow the intensity of the illumination light to be adjusted mechanically on the light source device side to prevent the blooming phenomenon described above, but when used in an endoscope inside a body cavity, the intensity of the illumination light can be adjusted depending on the distance to the subject. If the distal end of the insertion tube is curved, the distance to the body cavity wall will change in a complicated manner, making it almost impossible to achieve an appropriate illumination intensity in a short time. become.

Furthermore, when used in a body cavity, the reflected intensity increases if the affected area is moist with body fluids, and the appropriate illumination intensity varies depending on the condition of the affected area. On the other hand, if the illumination intensity is too low, it will be impossible to clearly image the affected area, which will impede diagnosis.

Furthermore, if it is attempted to incorporate a conventionally used aperture device into the distal end of the endoscope, the size of the aperture device will increase.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide an automatic light control device for endoscope imaging that can automatically adjust the light intensity to an illumination intensity suitable for imaging and is highly suitable for miniaturization. purpose.

[Summary of the invention]

The present invention variably adjusts the amount of light passing through a transparent section formed using a slit at the distal end of the insertion section of an endoscope using an electrical signal output according to the amount of light received by a solid-state image sensor. This allows the amount of light to be automatically adjusted to suit observation.

[Embodiments of the invention]

Hereinafter, the present invention will be specifically explained with reference to the drawings.

Figures 1 and 2 are used to assist in explaining the present invention; Figure 1 shows the endoscope, and Figure 2 shows the amount of light used to control the amount of transmitted illumination light. A part of a light shielding plate and a fly's eye lens, which are light shielding members serving as adjustment members, are shown in an enlarged manner.

The endoscope 1 has an objective lens 3 for imaging disposed at the distal end of a narrow-diameter insertion section 2, and a CCD (charge-coupled device) so that its imaging surface faces the imaging position of the objective lens 3. A solid-state image sensor 4 such as the above is disposed. A mosaic-shaped three primary color filter (not shown) is attached to the imaging surface of the solid-state image sensor 4, which transmits only light of each wavelength of the three primary colors through each light receiving element.
Depending on the clock signal applied to the solid-state image sensor 4, signals corresponding to each pixel that have passed through red, green, and blue transmission filters are sequentially output, and the signals have a low noise index. The color signals R, G, and B are amplified by a preamplifier 5, separated into R, G, and B signals by a sample hold circuit in the video processing unit 7 via a signal cable 6, and each amplified. The periodic signal is superimposed and inputted to the monitor color television 8, thereby forming an imaging means that can display it as a color image.

A light distribution lens 9 is disposed in the insertion section 2 so as to be adjacent to the objective lens 3.
The light guide 10 is inserted so that its output end faces inside.

The rear end of the light guide 10 on the proximal side can be detachably attached to the light source device 11.

At the rear end of the light guide 10, which is the input end of the illumination light, the illumination light of the illumination lamp 12 is connected to a reflecting mirror 13.
The light is reflected by the condenser lens 14, and is focused and irradiated by the condenser lens 14.

Therefore, the means for adjusting the illumination light irradiated onto the incident end of the light guide 10 by the illumination lamp 12 is formed as follows.

On the optical path between the condenser lens 14 and the illumination lamp 12, for example, at the pupil position of the condenser lens 14, as shown in FIG. Board 15
and a fly-eye lens 16 adjacent to the light shielding plate 15.
and are provided. On the side of the fly-eye lens 16 facing the light shielding plate 15, a light shielding plate having substantially the same shape as the light shielding plate 15 is attached, or by applying a light shielding paint, a light shielding portion 17A and a light shielding portion 17B are formed. The light shielding plate 15 and the fly's eye lens 16 form a light amount adjusting member.

The fly-eye lens 16 refracts the substantially parallel illumination light coming from the illumination lamp 12 side at each convex portion, condenses it on the concave portion on the other side, and condenses it on the light shielding plate 15 side ( It is designed so that it can be emitted to the opening side). This fly-eye lens 16 is fixed.

On the other hand, both upper and lower ends of the light shielding plate 15 are attached to the front ends of bimorph oscillators 18 and 19 as driving means, and the rear ends of the bimorph oscillators 18 and 19 are connected to the light source device 11 via a pedestal 20 and the like. It is fixed to the inner wall, etc.

A driving control signal is supplied to these bimorph vibrators 18 and 19 from a (bimorph) vibrator drive circuit 22 via a lead wire 21. As the level of this drive signal increases, the bimorph oscillators 18 and 19 are formed so that their front ends are displaced downward in the same phase with respect to their fixed rear ends (as shown by arrow A). It has been done,
Along with this displacement, the light shielding plate 15 also moves downward, so that the amount of illumination light passing through the opening of the light shielding plate 15 can be reduced.

The control input terminal of the vibrator drive circuit 22 receives each color signal R output from the video processing section 7,
A signal obtained by adding G and B in the adder 23 and further integrating the signal in the integrating circuit 24 is applied, and as the level of this signal increases, the level of the output signal of the vibrator drive circuit 22 increases. be. The adder 23 is used to maintain the color balance and produce a signal for dimming, and the integration circuit 24 is used to make the signal output from each light receiving element correspond to the light reception period. , the integrating circuit 24
is set to an integral time constant of about one frame or more, and the magnitude of this integrated signal level causes the fly's eye lens to be displaced from the maximum transmission area state that can pass through the aperture of the light shielding plate 15 as it is. The amount of illumination light passing through 16 can be reduced (as its level increases).

According to the structure configured in this way, the endoscope 1
When you move the camera closer to or farther away from the subject,
The amount of light incident from the illuminated subject changes depending on the distance, and therefore the optimum illumination intensity changes. The signals corresponding to each pixel output from the solid-state image sensor 4 in this state are taken in, the separated color signals R, G, and B are added for color display, and further integrated by the integrating circuit 24 to form one frame. The oscillator drive circuit 22 is driven by a dimming signal having a level that reflects the amount of incident light reflected from the subject during the period, and driving control signals are applied to the bimorph oscillators 18 and 19. Light shielding plate 1 according to the level of the above dimming signal or control signal.
1 to the appropriate illumination intensity in that state.
It is held every frame or so. Therefore, the operator does not have to adjust the illumination intensity to an appropriate value each time, and can concentrate on diagnosis or treatment, which is very convenient.

Furthermore, since the illumination intensity is automatically adjusted to an appropriate value, the affected area can be diagnosed in detail without the problem of being too dark, and accurate diagnosis or treatment can be performed.

FIG. 3 shows an auxiliary example used to further explain the invention.

In this example, illumination is performed using each of the three primary colors, and the illumination intensity of each of these colors is automatically adjusted while maintaining the color balance at an appropriate value.

That is, in this endoscope 31, each color signal R, G, B output through the video processing unit 7
are amplified by semi-fixed amplifiers 32R, 32G, and 32B via an adder 23 and an integrating circuit 24, respectively, and further inputted to the vibrator drive circuit 22 via a multiplexer 33.

The semi-fixed amplifiers 32R, 32G, and 32B are used to correct the spectral intensity distribution of the transparent light from the lamp 12, the wavelength transfer characteristics of the light guide 10, the photosensitive characteristics of the solid-state image sensor 4, and the like.

On the other hand, three primary color filters 3 are further installed in the vicinity of the light shielding plate 15 driven by the bimorph oscillators 18 and 19.
4, and the three primary color filters 34 are rapidly displaced by bimorph vibrators 36 and 37 driven by a drive signal from a vibrator drive circuit 35.

The three primary color filters 34 include red, green and blue color transmission filters 34R and 34 as shown in FIG.
G, 34B are formed in a stripe shape, and the spacing between each transmission filter is so formed that it can face the opening of the adjacent light shielding plate 15. It is designed to be vibrated and displaced. The vibrator drive circuit 35 is connected to power supplies 39R, 39G, 39 dedicated to each color by a multiplexer 38.
These multiplexers 38 and 33 are connected to the color frame switching circuit 4.
A switching signal of 0 is used to sequentially switch each color for each frame. By sequentially connecting the power supplies 39R, 39G, and 39B, the amount of displacement changes stepwise, and the transmission filter portion of the three primary color filter 34 facing the light projecting section 17B of the fly's eye lens 16 is 34R, 3
4G, 34B, 34R, ... are switched sequentially,
In response to this, the color of the illumination light irradiated onto the subject via the light guide 10 is sequentially switched to red, green, blue, red, . . . .

In this example, the black and white solid-state image sensor 4'
is used, and the video processing section 7 switches the output signal of the solid-state image sensor 4' for each frame using a switching signal from the color frame switching circuit 40 via a multiplexer or the like (not shown).
Each color signal is separated into R, G, and B, and outputted to a color monitor 8 to be displayed in each color in a time-division manner.

When the endoscope 31 according to the example configured in this way is used, the multiplexers 33 and 38 are switched synchronously, and the subject is sequentially photographed in each of the three primary colors through the color transmission filters 34R, 34G, and 34B of the three primary color filter 34. illuminated. The object illuminated in each color is then imaged on the imaging surface, converted into an electrical signal, and sequentially output from each photodetector with the application of each clock signal, charge transfer, or XY address signal, and after amplification, the image is converted into an electrical signal. It is taken into the process section 7. The video processing unit 7 separates the signals into R, G, and B color signals, which are sequentially displayed on a color television 8 in each color. At the same time, according to each output level of each color signal R, G, B, it passes through an adder 23 and an integration circuit 24 to a dimming signal that does not disturb the color balance, and after further color correction, the vibrator drive circuit 22 and then the light shielding plate 1
5 is automatically adjusted for each frame. Therefore, the illumination intensity of each color can be automatically adjusted to an appropriate intensity.

This auxiliary example allows for more faithful imaging or reproduction because it can perform color correction and automatic light adjustment for each color, and the monochrome solid-state image sensor 4' can use all of its photodetectors for each color of illumination. Therefore, it has the characteristic of improving resolution.

FIG. 5 shows the vicinity of the tip of the insertion section of an endoscope equipped with the first embodiment of the present invention.

In this embodiment, a slit 15 as shown in FIG. It is arranged at the pupil position of the optical lens 9. Note that one of the light shielding plates 41 is fixed, and the other light shielding plate 15 is attached to the bimorph resonator 1.
8 and 19, and is driven by the control signal of the transducer drive circuit 22 as shown in FIG. can be controlled.

FIG. 6 shows the vicinity of the tip of the insertion section of an endoscope equipped with a second embodiment of the present invention.

In this embodiment, instead of the light guide 10 in the first embodiment, a lamp 42 is provided as illumination means on the distal end side of the insertion section 2.

It is clear that a light emitting diode can be used instead of the lamp 42. In this case, if the three primary colors cannot be realized with a single light emitting diode, it is obvious that a plurality of light emitting diodes may be used so that the three primary colors can be used for illumination.

FIG. 7 shows the vicinity of the tip of the insertion section of an endoscope using the third embodiment of the present invention.

In this embodiment, the light shielding plate 1 shown in FIG.
5 and 41 and a driving means using bimorph oscillators 18 and 19 are provided on the entire surface of the solid-state image sensor 4', and automatic adjustment is performed by adjusting the amount of light received incident on the imaging surface. It is designed to do so.

In addition, in Fig. 5, Fig. 6, or Fig. 7,
Instead of the light shielding member using the two light shielding plates 15 and 41, a fly-eye lens 16 may be used as shown in FIG. 1 or 3.

Further, both of the two light shielding plates 15 and 41 can be displaced in opposite directions, or both of the light shielding plate 15 and the fly's eye lens 16 can be moved in opposite directions. moreover,
In FIG. 1 or 3, the light can also be adjusted by displacing the fly's eye lens 16 side.

In addition, CCD (charge coupled device) is used as a solid-state image sensor.
It is clear that the present invention is not limited to those using a charge transfer method such as the above, but can also be applied to those using an XY address method.

Note that in the example shown in FIG. 3 above, the adder 23
and the integrating circuit 24 includes semi-fixed amplifiers 32R, 32
It can also be provided on the output side of G and 32B.

Furthermore, it is clear that the present invention can be applied not only to color but also to black and white.

〔Effect of the invention〕

As described above, according to the present invention, the amount of transmitted light is controlled using a bimorph oscillator or the like to control the amount of illumination light irradiated to the subject side or the amount of light received incident on the imaging surface according to the signal level output from the solid-state image sensor. Since it is configured to be controlled by means, even if the observation distance to the subject is changed, the light can be automatically adjusted to an appropriate illumination intensity or incident light intensity suitable for observation.

It also has the advantage of being able to be stored in a small space.

[Brief explanation of the drawing]

1 and 2 relate to supplementary examples for explaining the present invention, and FIG. 1 is an explanatory diagram showing the entire endoscope;
FIG. 2 is a schematic cross-sectional view showing an enlarged peripheral part of a light amount adjusting member that adjusts the amount of transmitted light, and FIGS. 3 and 4 relate to other auxiliary examples for explaining the present invention.
The figure is an explanatory view showing the entire endoscope, FIG. 4 is a front view showing the structure of the three primary color filter, and FIG. 5 is a view showing the vicinity of the tip of the endoscope insertion part according to the first embodiment of the present invention. 6 is a sectional view showing the vicinity of the distal end of an endoscope insertion section according to a second embodiment of the present invention, and FIG. 7 is a sectional view showing the distal end of an endoscope insertion section according to a third embodiment of the present invention. FIG. 1, 31... Endoscope, 2... Insertion section, 3... Objective lens, 4, 4'... Solid-state image sensor, 5... Preamplifier, 7... Video processing section, 10... Light guide, 11 ... Light source device, 12 ... Illumination lamp, 13 ... Reflector, 14 ... Condenser lens, 15, 41 ... Light shielding plate, 16 ... Fly's eye lens, 17A ... Light shielding part, 17B ... Transparent Light part, 1
8, 19, 36, 37...bimorph oscillator, 2
2,40...bimorph resonator drive circuit, 23...
... Adder, 24... Integrating circuit, 33, 38... Multiplexer, 34... Three primary color filter, 40...
...Color frame switching circuit, 42...Lamp.

Claims (1)

[Claims] 1. An illumination means for illuminating a subject through a light distribution lens disposed at the distal end of the endoscope insertion section, and an imaging surface of a solid-state image sensor disposed at the distal end of the insertion section for illuminating the illuminated subject. In an endoscope apparatus, the endoscope apparatus is equipped with an imaging means capable of displaying the image as an image by capturing the signals of each light receiving element arranged on the imaging surface. A light amount adjusting member in which a pair of light shielding members each having a slit-shaped opening are disposed facing each other, at least one of the light shielding members is movable, and the area of the light transmitting portion is varied in accordance with the displacement; A driving means including a bimorph oscillator that displaces the light amount adjusting member according to the level of the input signal is provided, and the at least one of An automatic light control device for an endoscope, characterized in that one light shielding member is displaced.