JPS6215514A - Solid-state image pickup endoscope - Google Patents

Abstract

PURPOSE:To decrease the diameter of an endoscope greatly by arranging a light reflecting element between a lens and a solid-state image pickup element not at right angles to the optical axis of the lens. CONSTITUTION:Signal light 2 from the lens 1 is reflected by a prism 8 to strike the surface of the solid-state image pickup element 3 at right angles. Then, illumination light outputted by a waveguide fiber 5 illuminates an object through the prism 8 and lens 1. A chip substrate which constitutes the solid-state image pickup element 3 is connected by a wire 4 and the signal voltage of the solid- state image pickup element is outputted by a conductor 7. Then, the tip part 6 of the solid-state image pickup endoscope is equipped with said optical system and a pipe 9.

Description

[Detailed Description of the Invention] Technical field: The present invention relates to an endoscope, and particularly to an endoscope equipped with a solid-state imaging device at its tip.
゛ □I have a 4'h, compared to the previous Phi endoscope.
7 □' Ill ll'i□, -1 filed JP-A-5
9-16718fi, JP 188275 uses E/B vertical transfer method 4-filter solid-state imaging endoscope, full frame 1. , Aya Freno, Transfer C to T) Area sensor (F F 'T
Discloses a solid-state imaging endoscope that uses a ``area sensor''.

DISCLOSURE OF THE INVENTION The FFT area sensor using the above E/B vertical transfer method has a very small chip area and high resolution, so it can output more precise images than a fiber endoscope. However, the resolution of endoscopes was inferior to that of TTV, etc., and there was a strong demand for a change in the record. For example, if the resolution of gastrocameras were revised, it would be possible to detect smaller lesions in all prefectures. Therefore, the first objective of the present invention is to improve the resolution of solid-state imaging endoscopes.Furthermore, in order to alleviate patient pain, It is desired to further reduce the diameter of the solid-state imaging endoscope.However, it is a drawback that it deteriorates the resolution.The second object of the present invention is to reduce the diameter of the solid-state imaging endoscope. In order to solve the above-mentioned problems of endoscopes, the present invention discloses two German inventions. Since a synergistic effect can be obtained by implementing each invention together, they will be explained together. Be it.

Claim 1 (Independent Invention 1) The present invention provides that the surface of the solid-state image sensor is formed at a non-perpendicular angle to the optical axis of the lens.
In other words, it is characterized by being arranged in a diagonal or parallel direction. In this way, the diameter of the endoscope can be significantly reduced. That is, the horizontal or vertical width of the solid-state image sensor chip is considerably larger than the horizontal or vertical width of the imaging area. This is because the solid-state image sensing device necessarily includes a driving area (peripheral circuit area, wiring area, contact area, etc.) in addition to the imaging area. Generally, as the imaging area becomes smaller, the effective area ratio of the depth per imaging area/total chip area decreases. In endoscopes, k is generally 0. −~θ・γ or less. Furthermore, the chip needs to be covered with resin for insulation, which further increases the horizontal or vertical width of the resin body. Furthermore, since the wires connected to the contact areas of the chip are generally connected to electrode terminals on the same plane as the chip, the total area of the solid-state imaging device is considerably larger than the imaging area.

Conventionally, the surface of the solid-state image sensor (lens θ) was arranged perpendicular to the optical axis, so the cross-sectional area of the endoscope had to be at least -4 times larger than the area of the solid-state image sensor. In reality, the cross-sectional area of the endoscope must be much larger than the area of the solid-state image pickup device because various pipes and the like are present. These problems are significantly ameliorated by the present invention.

Claim 2: According to Clay's preferred embodiment, the solid-state imaging device is arranged in the 511th axis input to the endoscope in the 11th row of the scale. If the length is set to L, the area occupied by the light receiving system in the cross-sectional area of the endoscope will be significantly reduced.

Clay 133 In a preferred embodiment of claim 1, a prism is used as the light reflecting element. Part 1. A second solid-state image sensor is added to the endoscope, which is placed approximately directly along the optical axis. The signal light split by the prism 12 is then input to the two solid-state image sensors. In this way, the resolution can be improved by about twice. Conventional Priz 1\(
or half mirror) to split the signal light into two.
Plate solid-state cameras are known. However, it was not known that a two-plate solid-state camera could be built into an endoscope, and that the cross-sectional area of the endoscope could be significantly reduced as a result.

Of course, it is preferable that the pixel position of the second solid-state image sensor is relatively softer by approximately 1/2 pixel pitch in the horizontal or vertical direction with respect to the pixel position of the first solid-state image sensor. In a most preferred embodiment, the pixel position of the second solid-state image sensor is softened by 1/2 pixel pitch in both the horizontal and vertical directions relative to the pixel position of the first solid-state image sensor.

Claim 4 A drawback of claim 3 is that the area of the second solid-state image sensor increases the cross-sectional area of the endoscope. This embodiment solves this problem by making the second solid-state image sensor have a smaller imaging area than the first solid-state image sensor. In one preferred embodiment, the second solid-state image sensor only increases the resolution of the central region of the image.

Claim 5 In a preferred embodiment of claim 1, the solid-state image sensor receives signal light through a prism (1), and the illumination light is irradiated through the bristle shown in -1. 41. 1゜If you do this, the cross-sectional area of the illumination part will be the endoscope cross-section f.
You can reduce the f1i product.

Crano, 6 (Independent Invention 2) In order to improve the resolution of a solid-state imaging endoscope, the present invention arranges two or more partial photosensitive regions having different spectral sensitivities in one pixel-L of a solid-state imaging device, and 1/+! It is characterized by inputting illumination light with a spectrum of 1i to the intersection 1i. In this way, you can change the resolution. .

For example, an R (red) filter and a G filter are placed horizontally on one pixel.
(green) filter and B (blue) filter are arranged in order.

Then, irradiate R, G, and B light in order. As a result, R
During the signal output period after light irradiation, 11 images are output 111 times, and G
Six images are output during the signal output period after light irradiation, and 13 images are output during the signal output period after B light irradiation. As a result, the horizontal resolution is improved approximately three times. .

Of course, it is possible to arrange other color filters and to irradiate light with other spectrums, and it is also possible to arrange a plurality of partial photosensitive areas in the vertical direction of one pixel. Other features and advantages of the invention are illustrated by the following examples.

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 is a sectional view of one embodiment of a conventional solid-state imaging endoscope.

FIG. 2 is a sectional view of one embodiment of the present invention. The signal light 2 from the lens l is reflected by the prism 8 and inputted to the surface of the solid-state image sensor 3 at right angles. The illumination light output from the light guide fiber 5 illuminates the object via the prism 8 and the lens l. A chip and a substrate constituting the solid-state imaging device 3 are connected by a wire 4, and a signal voltage of the solid-state imaging device is outputted by a conductive wire 7. The distal end portion 6 of the solid-state imaging endoscope includes the optical system and pipe 9 described above. One part 8A of the lens prism 8 is provided with an antireflection film and a black filter. FIG. 3 is a front view of one embodiment of FIG. 2. The pipe 9 is a passage for water or compressed air, and is also a passage for a working handle. FIG. 4 is a modified embodiment of FIG. 3, and is a front view of one embodiment of FIG. The lens I is a circular lens whose peripheral part is cut, and the cross section of the pipe 9 is also not circular. As a result, the cross section of the endoscope 6 becomes approximately circular; 1. Maybe its area can be reduced. In the embodiments shown in FIGS. 2, 3, and 4, the illumination light that is input to the solid-state image sensor 3 without being reflected from the object becomes fixed noise. This fixed noise can be solved by storing the signal voltage output from the solid-state image sensor in a digital memory in the absence of signal light reflected from the target, and then subtracting the above stored voltage from the signal voltage that will be output later. Can be removed. Similarly, variations in sensitivity of each pixel of a solid-state image sensor can be compensated for by storing them in a digital memory and controlling the amplification factor of the signal voltage to be output later using the stored information. FIG. 5 is a cross-sectional view of an endoscope including a second solid-state image sensor arranged perpendicular to the optical axis 2. As shown in FIG. The second solid-state image sensor 11 is smaller than the first solid-state image sensor 3. In this embodiment, it is preferable that the light guide fiber be irradiated to one target without using the above-mentioned prism. FIG. 6 is a plan view of one embodiment of FIG. 5. The signal line of the second solid-state image sensor is taken out from the side. FIG. 7 is a plan view of one embodiment of the solid-state image sensor 1. An FFT area sensor using the IE/R vertical transfer method is mounted on the substrate 3A. Then, each electrode wire 7.7CA to D) is taken out from one end of the chip farthest from the lens. The imaging area 3C of the chip 3B is 256 (T(
') x 256 (v) pixels, each pixel is approximately 8
It has dimensions of x8 microns. As a result, the area of the imaging region is approximately 2 n+n+X 2 mm. FIG. 8 shows one example of the present invention.
FIG. 2 is a plan view of an embodiment, and is a plan view of an imaging area of a chip. Each pixel 14 in odd (even) pixel rows surrounded by the optical isolation region 13 is provided with an R filter and a G filter, and the R and G filters are arranged alternately in the horizontal direction. Similarly, each pixel in an even (odd) pixel row is connected to a G filter and a B filter.
The filters are provided alternately in the horizontal direction. Then, G light is emitted during the first irradiation period, and then six images are output.

Next, R-1-13 (magenta) light is emitted, and then an R18 image is output. A signal voltage is then applied to the display screen position corresponding to the position of each color filter.

In this way, the horizontal resolution can be doubled. FIG. 9 shows a modified embodiment of FIG. 8, in which each pixel is provided with two types of color filters, and the two-color filters indicated by - are arranged in the heavier direction.

By irradiating the G light and l'j +H)i- in an intersecting manner, the flat curve resolution is doubled.

Other features and advantages of the invention are described below. These characteristics are not in Kleeno, but in the future KleeJ\ can be.

As can be seen from FIG. 2, the first additional feature of the present invention is that a transparent substance (resin, glass, or liquid) is injected between the lens and the solid-state image sensor, between the lens and the light guide fiber, or between the lens prism 1. It is.

In this way, unnecessary reflections can be reduced and the S/N ratio can be improved. It is preferable that the difference in refractive index between the lens or prison and the above-mentioned transparent substance be small. A second additional feature of the invention is that the lens is non-circular in shape. In this way, the cross-sectional area of the endoscope can be significantly reduced. Third aspect of the present invention
An additional feature is that the pipe is used for both fluid passage and working handle communication.

In this way, the number of pipes can be reduced and the cross-sectional area of the endoscope can be reduced. For example, in FIG. 3 or 4, a protrusion 9A is installed on the inner surface of the pipe, and a work line (such as a forceps) 9B
to ensure movement within the pipe.

The sliding of the working line 9B is smoothed by 3L due to the presence of fluid in the pipe. In particular, it can be seen from FIGS. 31 and 4.

Similarly, the absence of a portion around the working line 9B reduces frictional resistance. As can be seen from FIG. 2, the fourth additional feature of the present invention is that the solid-state image pickup device is arranged closer to the center of the endoscope than the optical axis 2 of the lens 1. In this way, the area of the solid-state image sensor can be made larger, and the cross-sectional area of the endoscope can be easily made circular. A fifth additional feature of the present invention is to store a fixed noise voltage caused by illumination light input to the solid-state image sensor without passing through the target, and then output the fixed noise voltage from the signal voltage. This is to subtract the voltage. The above subtraction techniques using digital memory are well known to designers, so a detailed explanation will be omitted. In order to reduce the increase in lens noise, fixed noise voltage generation cycles were performed multiple times.1. It is preferable to memorize the average value of the fixed noise voltage obtained respectively. In addition, in FIG. 8, the color signal voltage (field signal type F) generated between different signal voltage outputs +gI (field period)
In order to display E) at a horizontal spatial position corresponding to the horizontal spatial position of the color filter, the color signal voltage output from the solid-state image sensor may be sampled 12 and displayed. This zumbling display technology is well known to those who have established the system, so a detailed explanation will be omitted. TV Society Journal VOT: I 7. N
It is also possible to use AM modulation techniques such as those described in OIO, page 830. In FIG. 8 or 9, the G voltage is obtained during the odd (even) field period, and the IN voltage is obtained during the even (odd) field period.

B voltage can be obtained. In a preferred embodiment, each field signal output from the solid state image sensor is written to digital memory and delayed for one field period. So(
, output from the solid-state image sensor during each field period)
The 5F field signal voltage and the 5F field signal voltage output from the digital memory are each sampled and displayed. By doing this, the color difference flicker occurring in Itl+ for the field period can be significantly reduced, and therefore has a very large effect in practical use. Naturally, each color signal type r+〕i
Since it is displayed during the J2 field period, it is against large movements)
7, a decrease in resolution occurs, but since the movement of the endoscope image is very small, there is almost no problem. Therefore, independent invention 2
The first additional feature is that the field signal (field image) voltage output from the solid-state image sensor is displayed in a plurality of adjacent field periods.

Screen flicker is significantly reduced. The second additional feature of Invention 2 is that a plurality of pure colors (R, G, G, R, G, R, G, R, G, R, G, R, G, R, G, R, G, R, G, R, G, R, G, etc.)

B) It is a matter of arranging color filters. In this way, the same color signal can be displayed at the spatial position corresponding to each color filter area of the solid-state image sensor, so the resolution will be greatly improved. When a complementary color filter is used, the resolution is reduced due to the circuit that determines the ratio of the pure color double voltage included in the signal voltage.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of a conventional solid-state imaging endoscope. FIG. 2 is a sectional view of one embodiment of the present invention. 3 and 4 are front views of one embodiment of the endoscope of FIG. 2, respectively. FIG. 5 is a partial cross-section IR+ of the two-panel solid-state imaging endoscope of the present invention. FIG. 5 is a plan view of one embodiment of FIG. 4. FIG. 7 is a plan view of one embodiment of the solid-state image sensor 3. As shown in FIG. 8 and 9 are color filter arrangement diagrams arranged in the pixel area of the solid-state image sensor 3.
. Patent applicant [Case 1 of 11 - Procedural amendment (formality)

Claims (6)

[Claims] (1) In an endoscope equipped with a lens and a solid-state image sensor at its tip, a light reflecting element is arranged between the lens and the solid-state image sensor, and the surface of the solid-state image sensor is aligned with the optical axis of the lens. A solid-state imaging endoscope is arranged at a non-perpendicular angle to the lens, and light input from the lens is reflected by the light reflecting element and input to the solid-state imaging device. (2) In the solid-state imaging system according to item 1, the solid-state imaging device is arranged approximately parallel to the optical axis of the lens, and the light reflecting element reflects the input light approximately at right angles. Endoscope. (3) The light reflecting element described above is a prism and includes a second solid-state image sensor, and the light split by the prism is input to the two solid-state image sensors. The solid-state imaging endoscope according to item 1. (4) The solid-state imaging endoscope according to item 3, wherein the second solid-state imaging device has a smaller chip area than the other solid-state imaging devices. (5) The solid-state imaging endoscope according to item 1, wherein the light reflecting element is a prism, and the illumination light is output through the prism and the lens. (6) In an endoscope equipped with a solid-state image sensor, some or all of the pixels of the solid-state image sensor are provided with a plurality of color filter regions each having a different transmission spectrum, and the illumination light of the different spectrum is periodically provided. A solid-state imaging endoscope characterized by inputting.