JPH0646265B2 - Endoscopic device for visible / infrared light - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a visible light / infrared light endoscope apparatus capable of imaging not only visible light but also infrared light.

[Technical Background of the Invention and Problems Thereof] In recent years, an imaging apparatus using a solid-state imaging device is being realized even in an endoscope.

However, in a conventional endoscope using a solid-state image sensor, an endoscope capable of imaging light in the visible region, but capable of diagnosing a condition or symptom of an affected area in more detail is desired. .

For diagnosing the condition or symptom of the affected area, examining the state of fever of the affected area, that is, the temperature distribution map is an effective means.

The temperature distribution can be known by receiving the light in the infrared region emitted by the heating element such as the affected area.

Therefore, it is possible to observe or diagnose with visible light,
An endoscope capable of observing or diagnosing with infrared light is desired, but the conventional example disclosed in JP-A-58-46929 is one in which an image with infrared light can be displayed as a contour at a constant level. And is not enough to get more information.

Further, the conventional example disclosed in Japanese Patent Laid-Open No. 58-42222 can be used with (near) infrared light, but the solid-state image pickup device must be rotated electromagnetically or mechanically, The tip side of the part becomes bulky or complicated. Further, since a plurality of solid-state image pickup elements are used, the cost becomes high. Further, a conventional example in which a plurality of image pickup means are provided together is also disclosed, but in this case as well, it is bulky and costly as described above.

[Object of the Invention] The present invention has been made in view of the above points, and visible light / infrared light that can be imaged not only by visible light but also by infrared light, and can be realized at low cost without being bulky. An object is to provide an endoscope apparatus for light.

SUMMARY OF THE INVENTION According to the present invention, a visible light image is formed by forming a filter portion that transmits visible light and a filter portion that transmits infrared light, processing a signal output from a light receiving element through each filter. Of course, infrared light images can also be taken.

Embodiments of the Invention Hereinafter, the present invention will be specifically described with reference to the drawings.

1 to 5 relate to a first embodiment of the present invention.
The figure shows the endoscope of the first embodiment, FIG. 2 shows the arrangement of the light receiving elements on the image pickup surface of the solid-state image pickup element, and FIG. 3 shows the filter arranged in front of the image pickup surface. FIG. 4 shows a three primary color filter, and FIG. 5 shows a liquid crystal filter.

In the endoscope 1 of the first embodiment, an objective lens 3 for image formation is arranged on the tip side of a small-diameter insertion portion 2, and a CCD is formed so that its image pickup surface faces the image formation position of the objective lens 3. (Charge imaging device)
An image pickup optical system is formed by disposing solid-state image pickup elements 4 such as. As shown in FIG. 2, for example, square light receiving elements 5 are regularly arranged on the image pickup surface of the solid-state image pickup element 4, and filters 6 are arranged in front of these light receiving elements 5 ,.

As shown in FIG. 3, the filter 6 includes a light receiving element 5,
The portion covering the odd rows in the array of ..., 5 is the visible light transmitting filter 6a which is transparent to visible light (shields only infrared light), and the portion covering the even rows shields visible light and It is formed of an infrared light transmitting filter 6b (a satin-like portion) that transmits light.

Then, a signal corresponding to each pixel is sequentially output by the clock signal applied to the solid-state image sensor 4, and the signal is amplified by the preamplifier 7 having a low noise figure. Color amplifiers 10R, 10G, 10 which are conducted by a multiplexer 9 via a signal cable 8.
In B, it is further amplified sufficiently.

A clock signal received by the solid-state imaging device 4 and applied to read a signal corresponding to each pixel is output from the signal reading circuit 11, and the clock signal is formed by the reference oscillation device 12 by the reference signal. It has become.

The reference signal is input to the horizontal deflection circuit 13 and the vertical deflection circuit 14 to form horizontal and vertical deflection signals, which are applied to the X and Y deflection terminals of the color cathode ray tube 15. In the normal visible image pickup mode, the red, green and blue color signals R, G and B output from the color amplifiers 10R, 10G and 10B are displayed on the color cathode-ray tube 15 while being swept horizontally and vertically. ing.

In the multiplexer 9, three terminals are sequentially switched in the visible image pickup mode by the switching signal of the switching circuit 16 which outputs a switching signal formed by dividing the clock signal output from the signal reading circuit 11. It is like this.

By the way, a light guide 17 formed of a fiber bundle is inserted into the insertion portion 2 as an illumination light transmission means, the rear end of the light guide 17 is detachably attached to the light source device 18, and the front end thereof is illuminated. It is configured so as to emit light and illuminate the subject side in a range that can be observed by the objective lens 3 via the light distribution lens 19.

An illumination lamp 21 is provided in the light source device 18, and the illumination light of the illumination lamp 21 is reflected by a rear reflecting mirror 22 and guided to the front condenser lens 23 side, and is condensed by the condenser lens 23. The rear end face of the light guide 17, that is, the incident end face is irradiated.

On the optical path between the illumination lamp 21 and the condenser lens 23, for example, a liquid crystal filter (liquid crystal plate) 24 and a three primary color filter 25 are arranged at the pupil position of the condenser lens 23.

The three primary color filters 25 are, as shown in FIG. 4, a red transmission filter 25R that transmits only light of red color (wavelength), a green transmission filter 25G that transmits only light of green color, and light of blue color. The blue transmission filter 25B that transmits only the light and the blue transmission filter 25B have a stripe shape, and these transmission filters 25R, 25G, and 25B.
The stripe pattern is formed so as to be repeated in this order.

Further, electrodes are formed on the entire surface of one side of the liquid crystal filter 24, and stripe-shaped electrodes are formed on the other side of the surface of the other side, as shown in FIG. , Each color filter 25R of the same color,
The electrodes in contact with the 25G and 25B portions are electrically connected to form three electrodes 24a, 24b and 24c as a whole. Then, when a voltage is applied, the liquid crystal portion between the electrodes serves as a light-transmitting portion that allows light to pass therethrough, and when applied, the liquid crystal portion between the electrodes serves as a light-shielding portion that shields light (reversely, of course). May be).

The three electrodes 24a, 24b, 24c are connected to respective common terminals of the multiplexer 26 via lead wires so that the voltage of the battery 27 can be applied.

The multiplexer 26 is sequentially switched by the switching circuit 16 so that a voltage is applied to each of the electrodes 24a, 24b, 24c one by one, and the other two are switched so as to be electrically connected to the ground.

Regarding the multiplexers 9 and 26, in the case of imaging with visible light, a voltage is sequentially applied to the electrodes 24a, 24b, 24c by the multiplexer 26, and the red, green, and green light transmitted through the three primary color filters 25R, 25G, 25B are transmitted. An image pickup means in which the signals received by the respective light receiving elements 5, ..., 5 are sequentially read twice for each odd-numbered array line shown in FIG. 3 while being sequentially illuminated with blue illumination light and illuminated with each color. And the read (acquired) signal is sequentially amplified by the color amplifiers 10R, 10G, and 10B and displayed on the color cathode-ray tube 15 while being swept by the horizontal and vertical deflection signals.

On the other hand, when imaging with infrared light is selected (by switch operation (not shown) or the like), in the multiplexer 26, the electrodes 24a, 24b, and 24c of the liquid crystal filter 24 are grounded and shielded, or the illumination lamp 21 is turned off. To be done. Then, the multiplexer 9 includes all the color amplifiers 10R, 10G, 1
The infrared light transmitting filter 6b shown in FIG.
, 5 are sequentially read out (captured so that they can be displayed), and the read out signals are amplified and repeated twice to form 2 fields as 1 frame. The (interlaced scanning) color cathode-ray tube 15 is provided with image pickup means (infrared light) displayed as a black-and-white image and display means for monitoring the picked-up image. Incidentally, the color amplifiers 10R, 10G, 10B
In order to make all of them conductive, for example, an analog switch (not shown) or the like is connected to the common end of the multiplexer 9 and each color amplifier 10
This is possible by turning on the input terminals of R, 10G, and 10B, respectively.

According to the first embodiment configured as described above, when it is desired to capture an image with visible light, the switching circuit 16 causes the multiplexers 9 and 26 to operate, and under illumination of each color,
By the clock pulse of the signal reading circuit 11, each light receiving element 5, ..., 5 in an odd row on the imaging surface of the solid-state imaging element 4
It is possible to sequentially read the signal of each of the two signals, repeat the two fields, and amplify by the color amplifiers 10R, 10G, and 10B to sequentially display the image of each color on the color cathode-ray tube 15, and make the display cycle of each color shorter than the afterimage time. The image is visually displayed as a color image by repeatedly displaying it.

On the other hand, when it is desired to capture an image with infrared light, each color amplifier 10
The input ends of R, 10G, and 10B are electrically connected to the output end of the preamplifier 7, the illumination light of the illumination lamp 21 is turned off or shielded, and the signal output of each light receiving element 5, ... By amplifying by 10R, 10G, and 10B and displaying on the color cathode ray tube 15, the image of a subject such as a diseased part by infrared light can be displayed in black and white contrast.

Therefore, it is possible to capture an image with normal visible light and display it as a color image, and it is also possible to easily capture and display a desired site such as an affected area even with infrared light. Can be done accurately.

The solid-state image sensor 4 is of a scanning type in which the signals of the respective light receiving elements 5, ..., 5 are sequentially scanned by a clock signal and output, and like the ordinary scanning type, an odd field and an even field are used. The field can be sequentially switched and output. The XY address system can be applied to any system as long as the Y address is sequentially increased by an odd number or an even number.
Even when the focus of visible light differs from the focus of infrared light due to the objective lens 3, the refractive index and the thickness of the infrared transmission filter 6b and the visible light transmission filter 6a, if necessary, are different. In any case, a clear image can be formed on each of the odd-side and even-side light-receiving elements 5, ...

FIG. 6 shows a second embodiment of the present invention.

In the endoscope 31 of this embodiment, a filter 6'as shown in FIG. 7 is attached to the front surface of the solid-state image pickup device 4, for example.

The portion of the filter 6'covering the light receiving elements 5, ..., 5 in the even rows is formed by the infrared light transmitting filter 6b similarly to that shown in FIG. 3, while the light receiving elements 5, 5 in the odd rows are formed.
.., 5 are formed by the three primary color filters in a normal mosaic arrangement.

That is, in the three-primary-color filter portion, the green transmission filters 6G and the blue transmission filters 6B that transmit only the green and blue colors respectively are alternately arranged in the first row, and the red transmission filters 6R and 6R are arranged in the third row. The green transmission filters 6G are arranged alternately, and the fifth and subsequent rows have an arrangement pattern in which these are repeated.

The signal read by the solid-state image sensor 4 is amplified by the preamplifier 7, and the sampling pulse of the sampling pulse generating circuit 32 has a short pulse width, and the (sample) hold circuits 33R, 33G, and 33B for red, green, and blue. Are sequentially captured by the color cathode ray tube 1 while being swept by the horizontal and vertical deflection outputs after being amplified by the color amplifiers 10R, 10G and 10B, respectively.
5 is displayed.

For imaging with visible light, each light receiving element 5, ...
, 5 are read out and taken into corresponding sample hold circuits 33R, 33G, 33B according to the color transmission filters covering the respective light receiving elements 5 ,.

On the other hand, for imaging with infrared light, the sampling pulse generation circuit 32 uses the sample hold circuits 33R and 33R.
A sampling pulse is output to G and 33B at the same time, captured by the sample and hold circuits 33R, 33G and 33B for each color, amplified respectively and applied to the electron gun of each color of the color CRT 15 to display as a black and white image. I am doing it.

In both visible light and infrared light, one frame of image is formed by repeating two fields as described in the first embodiment.

Further, the signal reading clock is applied in the even field after the odd field, and the sampling pulse is also sampled in accordance with this, thereby forming an image with visible light and infrared light, and superimposing the image on the color CRT 15. It can also be displayed.

Note that the above-mentioned infrared signal capture is simultaneously captured by the three sample hold circuits 33R, 33G, and 33B.
Although it is displayed substantially as a luminance signal, it can be displayed in any color of red, green, or blue by incorporating it into a single sample and hold circuit. This also applies to the first embodiment.

The operational effects of the second embodiment are substantially the same as those of the first embodiment.

FIG. 8 shows an endoscope according to the third embodiment of the present invention.

In the endoscope 41 of this embodiment, both ends (upper and lower sides) of the filter 6 (shown in FIG. 3) of the first embodiment (upper and lower sides) thereof are slightly separated from the image pickup surface of the solid-state image pickup element 4 and the bimorph oscillator 42 is provided. , 42, which are attached to the front ends of the bimorph oscillators 42, 42, and the rear ends of the bimorph oscillators 42, 42 together with the solid-state imaging device 4 are provided with support members 4
It is fixed to the inner wall of the insertion portion 2 via 3.

The bimorph oscillators 42, 42 are provided with a drive circuit 44.
A pulsed drive signal is supplied from the lead wire 45. This drive signal is the reference oscillator 1
The pulse signal is formed by dividing the frequency of the second signal or the clock signal of the signal reading circuit 11 and is changed from the high level to the low level and from the low level to the high level every time one field signal is read. When applied, both bimorph vibrators 42, 42 move in the vertical direction (vertical direction) on the front end side with the rear end as a fulcrum, and the amount of movement is between the centers of the light receiving elements 5, ..., 5 adjacent in the vertical direction. The distance d (see FIG. 3) can be moved every one field period (one vertical scanning period). In this embodiment, the filter 6 is formed with an extra one line, for example, on the upper side (for example, this portion is an infrared light transmitting filter 6b). When imaging with visible light,
The signal is read from each of the light receiving elements 5, ...
When a high-level pulse is supplied to 2 and 42, the filter 6 is displaced downward by d, and in this state, the signals of the light receiving elements 5, ..., 5 in the even rows are read. When the signal reading of the light receiving elements 5, ..., 5 in the even-numbered rows is completed, the pulse becomes low level, and the multiplexers 9 and 26 are switched to perform the same operation under the illumination of other colors. . The read signals are amplified and sequentially displayed on the color cathode ray tube 15.

In this way, since the image is picked up by using all the light receiving elements 5, ..., 5 for each color, an image with excellent resolution can be obtained.

On the other hand, when capturing an image of infrared light, the multiplexer 9
Is conducted simultaneously with the input terminals of the color amplifiers 10R, 10G and 10B, and the illumination light is blocked or turned off.

Then, signal reading is performed (display is also performed at the same time) by using each of the light receiving elements 5, ..., 5 in the even rows initially covered with the infrared transmission filter 6b, and when reading of one field is completed, A pulse having a high level is applied to the bimorph oscillators 42, 42, and the pulse moves the filter 6 downward by d. In this state, the signals of the light receiving elements 5, ..., 5 in the odd rows are read. . Therefore, it is possible to perform imaging and reproduction with excellent resolution even for infrared light.

In the third embodiment, the filter 6 disposed on the front surface of the solid-state image pickup device 4 in the first embodiment described above is oscillatingly displaced so that an image with excellent resolution can be obtained. However, similarly, the resolution can be increased by displacing the filter 6 '(see FIG. 7) of the second embodiment in the vertical direction by d.

Although no memory is used in each of the above embodiments,
A memory for each color frame may be prepared so that a still image or the like can be displayed. If a video tape recorder or the like is used, it can be reproduced and examined later, or stored as a material for diagnosis.

In addition, in the above-described embodiment, the illumination lamp 21 in the light source device 18 is formed with the light guide 17 to form the illumination means with visible light, but the present invention is not limited to this, and the illumination device is inserted. It is obvious that the subject can be illuminated by using a lamp, a light emitting diode or the like on the tip side of the portion 2.

Further, in each of the above-mentioned embodiments, the illumination means with infrared light is not formed, but it may be effective depending on the symptom by examining the reflection intensity etc. with infrared light. Illuminating means with infrared light may be provided in the light source device 18 or at the tip end side of the insertion portion 2 or the like, and this case also belongs to the present invention.

In the above embodiment, the bimorph oscillator is used as the means for displacing the filters 6 and 6 ', but it can also be driven by using an ordinary piezoelectric oscillator or electromagnetic force.

Although the filters 6 and 6'are driven in the above embodiment, it is clear that the solid-state image sensor 4 side may be driven, and this example also belongs to the present invention. still,
In this case, even in the case of visible light or infrared light, it is possible by repeatedly using half of the light receiving elements 5, ..., 5 in synchronization with the displacement.

In each of the above embodiments, the infrared light transmitting filter 6b is used.
Has a property of blocking visible light. It is possible to turn off the illumination light with visible light or the liquid crystal filter 25.
When it is shielded by, for example, visible light is not received at all, or almost no visible light is received. In such a case, the infrared light transmitting filter 6b is practically used if it has a filter characteristic of transmitting at least infrared light. However, the present invention also includes this case. Further, a device provided with a means for illuminating with only infrared light is sufficiently practical.

The infrared light transmission filter 6b is not limited to the array as in the above-described embodiment, and the infrared light transmission filter 6b formed so as to cover at least the plurality of light receiving elements 5, ... It belongs to the present invention.

Further, although the present invention enables color imaging with respect to visible light, the present invention also relates to what can be displayed in monochrome (including black and white) or in black and white in addition to color.

[Effects of the Invention] As described above, according to the present invention, in addition to a filter portion that transmits visible light, a filter that transmits infrared light is provided, and a light receiving element that receives light through these filters is provided. Since the output signal can be read, it is possible to image with visible light and infrared light with one endoscope. Therefore, in addition to the normal visible light image, it is possible to diagnose by an infrared light image,
More accurate diagnosis or therapeutic treatment can be performed.

Further, since it can be housed in a small space with a simple structure and also serves as a solid-state image pickup device, it can be realized at low cost.

[Brief description of drawings]

1 to 5 relate to a first embodiment of the present invention.
FIG. 1 is an explanatory view showing the configuration of the endoscope of the first embodiment, FIG. 2 is a front view showing the arrangement of light receiving elements on the image pickup surface of a solid-state image pickup element, and FIG. 3 is arranged in front of the image pickup surface. FIG. 4 is a front view showing a filter, FIG. 4 is a front view showing a three primary color filter, and FIG.
FIG. 6 is a front view showing a liquid crystal filter, FIGS. 6 and 7 are related to a second embodiment of the present invention, FIG. 6 is an explanatory view showing a configuration of an endoscope of the second embodiment, and FIG. FIG. 8 is a front view showing the filter arranged on the front surface of the image pickup surface, and FIG. 8 is an explanatory view showing the configuration of the endoscope of the third embodiment of the present invention. 1,31,41 …… Endoscope 2 …… Insertion part, 3 …… Objective lens 4 …… Solid-state imaging device, 5 …… Light receiving device 6,6 ′ …… Filter 6a …… Visible light transmission filter 6b …… Infrared light transmission filter 7 ... Preamplifier 9,26 ... Multiplexer 10R, 10G, 10B ... Color amplifier 11 ... Signal reading circuit 15 ... Color cathode ray tube 17 ... Light guide 18 ... Light source device, 21 ... ... Illumination lamp 23 ... Condenser lens 24 ... Liquid crystal filter, 25 ... 3 primary color filter 42 ... Bimorph oscillator 44 ... Drive circuit

Claims (1)

[Claims] 1. An illumination lamp for generating illumination light, a condenser lens for converging the illumination light of the illumination lamp to enter a light guide, and an optical image is taken based on the illumination light emitted from the light guide. An image pickup device, a visible light transmission filter and an infrared light transmission filter arranged in a predetermined arrangement on an image pickup surface of the image pickup device, and an optical path between the illumination lamp and the condenser lens, A liquid crystal filter provided at the pupil position of the condenser lens, a filter means provided in the liquid crystal filter and arranged in a predetermined arrangement with a plurality of color filters transmitting visible light of different wavelengths; By controlling the application of a voltage provided to the liquid crystal filter corresponding to the array, and controlling the application of the voltage to the electrode means for forming the light-shielding portion and the light-transmitting portion in the liquid crystal filter. To, and control means for controlling reading of the signal of the image pickup device, wherein, when the image pickup by the visible light is selected,
By controlling the voltage applied to the electrode means provided for the color filter, illumination light of visible light of different wavelengths,
The signal of the region in which the visible light transmission filter of the image sensor is arranged is read according to the illumination light that is sequentially generated and is sequentially emitted, and when the image pickup by infrared light is selected, the illumination by the visible light is performed. While stopping the irradiation of light,
An endoscope apparatus for visible light / infrared light, which is controlled so as to read out a signal in a region in which the infrared light transmitting filter of the image pickup device is arranged.