JP2004337379A - Solid state imaging element, electronic endoscope, and electronic endoscope apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an observation image of high quality without thickening the diameter of a cylindrical device or without lowering a dynamic range even if built in a cylindrical device. <P>SOLUTION: A solid state imaging element includes a first photodetecting part and a second photodetecting part in which a plurality of photodetecting elements are disposed at a predetermined pitch in a matrix state on different regions of a predetermined direction on a single semiconductor substrate formed in a long length in the predetermined direction. The plurality of the photodetecting elements included in the first photodetecting part and the plurality of the photodetecting elements included in the second photodetecting part are disposed by deviating at a half of the pitch in a direction perpendicular to the predetermined direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solid-state imaging device in which a plurality of light-receiving elements are arranged in a matrix on a single semiconductor substrate, an electronic endoscope having the solid-state imaging device at a distal end thereof, and furthermore, the electronic endoscope. The present invention relates to an electronic endoscope device provided with:
[0002]
[Prior art]
BACKGROUND ART Conventionally, by reducing the diameter of an insertion portion of an endoscope, pain of a patient when the endoscope is inserted into a body cavity, particularly, into a thin tubular organ, is reduced. In recent years, electronic endoscopes (electronic scopes) having a solid-state imaging device such as a CCD at the distal end of the insertion section have become widespread, and various components provided inside the insertion section have been reduced in size. This achieves a smaller diameter. The smaller the endoscope or electronic endoscope, the more it can be inserted into the body cavity and the more freely it can be moved inside the body cavity. Have been.
[0003]
Many electronic endoscopes are equipped with a monochrome CCD suitable for miniaturization for the reasons described above. However, in recent years, in order to observe the state of a living tissue more accurately, a device for obtaining a color image has been put to practical use. There are two main types of devices for obtaining this color image. One is a so-called simultaneous method in which a color image is obtained by using a color filter such as RGB on the front surface of each of a plurality of light receiving elements arranged in a matrix on a CCD. The other is to obtain a color image by imaging a living tissue illuminated with illumination light of each color through a rotating color filter of a light source device connected to an electronic endoscope with a monochrome CCD, so-called plane sequential. This is a method using a method.
[0004]
However, in recent years, further reduction in the diameter of the electronic endoscope has been required, and it is necessary to further reduce the size of the CCD and the like provided at the distal end. In order to reduce the size of the CCD, it is necessary to reduce the size of each light receiving element. However, as the size of each light receiving element is reduced, the amount of charge that can be accumulated per light receiving element decreases. Therefore, the dynamic range of the photographable brightness is reduced.
[0005]
The biological tissue in the body cavity, which is the object to be observed by the electronic endoscope, is observed by illuminating the interior of the body cavity, which is a dark part, with an illumination device. It tends to be particularly large compared to images such as videos. Therefore, when the dynamic range is reduced, if the brightness of the bright part is set to an appropriate level, the image of the dark part will be crushed black, and if the luminance of the dark part is set to the appropriate level, the phenomenon that the image of the bright part will be white will frequently occur. turn into.
[0006]
Therefore, conventionally, a pair of adjacent light receiving elements having different sensitivities, the electric charge accumulated in each light receiving element is transferred, and the electric charge of the pair of light receiving elements is added to improve the dynamic range ( For example, see Patent Document 1). In addition, a color filter of the same color is mounted for every predetermined number of adjacent pixels, and the electric charge obtained by the predetermined number of pixels of the same color is added according to the set mode to improve the dynamic range and sensitivity. (For example, see Patent Document 2).
[0007]
[Patent Document 1]
JP-A-9-252107 (pages 3 to 5, FIG. 1)
[Patent Document 2]
JP-A-11-298800 (pages 3, 4 and 2)
[0008]
[Problems to be solved by the invention]
However, in the solid-state imaging devices described in Patent Literature 1 and Patent Literature 2 described above, a signal equivalent to one pixel is output by adding charges accumulated in a plurality of pixels. Will decrease. In other words, although the dynamic range and sensitivity can be improved to improve image collapse and overexposure, the output image becomes unclear due to a decrease in resolution. Therefore, it becomes difficult for the surgeon to accurately grasp the state of the details of the living tissue from the image of the living tissue displayed on the monitor.
[0009]
When the amount of charge that can be stored is increased by increasing the size per pixel in order to improve the dynamic range while maintaining the resolution, the dynamic range can be improved smoothly without reducing the sharpness of the image. Images can be obtained. However, in order to increase the size of the light receiving element per pixel while maintaining the number of pixels, there is a limit in reducing the size of the solid-state imaging device, and as a result, the diameter of the electronic endoscope is reduced as desired. Therefore, the burden on the patient cannot be reduced.
[0010]
Therefore, in view of the above circumstances, the present invention does not increase the diameter or reduce the dynamic range even when incorporated in a cylindrical device, and can obtain a high-quality observation image, It is another object of the present invention to provide an electronic endoscope including the solid-state imaging device, and an electronic endoscope apparatus including the electronic endoscope.
[0011]
[Means for Solving the Problems]
A solid-state imaging device according to one embodiment of the present invention that solves the above-described problem includes a plurality of light-receiving elements at different pitches in a predetermined direction on a single semiconductor substrate formed to be longer in a predetermined direction. Has a first light receiving portion and a second light receiving portion arranged in a matrix, each of the plurality of light receiving elements included in the first light receiving portion, and a second light receiving portion. Each of the plurality of light receiving elements included in the portion is arranged so as to be shifted from each other by a half of the pitch in a direction orthogonal to a predetermined direction.
[0012]
The solid-state imaging device further includes a charge-coupled device in which the solid-state imaging devices are arranged in a row in a predetermined direction adjacent to the first light receiving unit and the second light receiving unit. This charge-coupled device includes a first transfer unit that is a transfer destination of the charge accumulated in the first light receiving unit and a second transfer unit that is a transfer destination of the charge accumulated in the second light receiving unit. It also has more.
[0013]
In addition, an electronic endoscope according to one embodiment of the present invention that solves the above-described problem includes an objective optical system that forms an image of a subject and a single semiconductor substrate that is formed to be long in a predetermined direction. A solid-state imaging device having a first light-receiving unit and a second light-receiving unit in which a plurality of light-receiving elements are arranged in a matrix at different pitches in different regions; a first light-receiving unit and a second light-receiving unit; A light beam separating means for separating the subject image toward the first light receiving portion and the second light receiving portion so that the subject image is formed at the light receiving portion of the light receiving portion. The separating means has a function of guiding a subject image which is relatively shifted by a half of the pitch in a predetermined direction and a direction orthogonal to the predetermined direction with respect to each of the first light receiving unit and the second light receiving unit.
[0014]
In addition, an electronic endoscope according to another aspect of the present invention that solves the above-described problems includes an objective optical system that forms an image of a subject and a single semiconductor substrate that is formed to be long in a predetermined direction. A solid-state imaging device having a first light-receiving unit and a second light-receiving unit in each of which a plurality of light-receiving elements are arranged in a matrix at predetermined pitches in different regions; A light beam separating means for separating the subject image toward the first light receiving unit and the second light receiving unit so that the subject image is formed at the second light receiving unit; The solid-state imaging device is arranged such that each of the first light receiving unit and the second light receiving unit receives a subject image which is relatively shifted by a half of a pitch in a predetermined direction and a direction orthogonal to the predetermined direction.
[0015]
Further, in the electronic endoscope, the solid-state imaging device is arranged so that the longitudinal direction of the semiconductor substrate and the longitudinal direction of the distal end portion match. Further, the solid-state imaging device further includes a charge-coupled device adjacent to the first light receiving unit and the second light receiving unit and arranged in a line in a predetermined direction. This charge-coupled device includes a first transfer unit that is a transfer destination of the charge accumulated in the first light receiving unit and a second transfer unit that is a transfer destination of the charge accumulated in the second light receiving unit. It also has more.
[0016]
An electronic endoscope apparatus according to one embodiment of the present invention that solves the above-described problem includes the electronic endoscope according to any one of claims 3 to 6 and a first light receiving unit. Between each of the plurality of pixels imaged by each of the plurality of light receiving elements, so that each of the plurality of pixels imaged by each of the plurality of light receiving elements included in the second light receiving unit is located And a processor having a signal processing unit for synthesizing image signals obtained from the first light receiving unit and the second light receiving unit.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram illustrating a configuration of an electronic endoscope apparatus 500 including an electronic endoscope 100 according to an embodiment of the present invention. The electronic endoscope apparatus 500 includes an electronic endoscope (electronic scope) 100 that outputs image information in a body cavity of a patient, and performs predetermined processing on the image information output to the electronic endoscope 100 to generate a video signal. A processor 200 including a light source device for supplying a light beam for obtaining an observation image to the electronic endoscope 100 in addition to the image processing device for conversion, and displaying the inside of a patient's body cavity based on a video signal output from the processor 200 The monitor 300 is configured. The configuration and operation of the electronic endoscope device 500 will be described below with reference to FIG.
[0018]
The processor 200 includes a light source unit (light source lamp) 210 that emits illumination light that illuminates the living tissue 400 to be observed in the present embodiment. In the electronic endoscope apparatus 500 of the present embodiment, a plane-sequential imaging system is employed in order to reduce the diameter of the distal end of the electronic endoscope 100. Therefore, the illumination light emitted by the light source 210 is It is white light, and an RGB rotation filter 220 is arranged on the optical path.
[0019]
The RGB rotation filter 220 has three color filters of R (red), G (green), and B (blue), and a light shielding unit. These three color filters are filters that transmit only the corresponding one color light. The RGB rotation filter 220 has a color filter (R), a light shielding unit, a color filter (G), a light shielding unit, a color filter (B), and a light shielding unit in the rotation direction. Hereinafter, a process of generating a color image by the frame sequential method using the RGB rotation filter 220 will be described.
[0020]
First, the timing generator 230 transmits a drive signal to a motor driver (not shown). The motor driver drives the motor 222 based on the received drive signal. Since the rotation shaft of the motor 222 rotatably supports the RGB rotation filter 220, the RGB rotation filter 220 rotates with the driving of the motor 222. The illumination light emitted from the light source unit 210 by the rotation of the RGB rotation filter 220 intermittently passes through the filters of R, G, and B by the light-shielding units provided therebetween.
[0021]
The processor 200 is connected to the electronic endoscope 100 by a connector 280. Each of the illumination lights transmitted through the respective filters of the RGB rotation filter 220 enters the light guide 110 of the electronic endoscope 100 via the condenser lens 224 arranged on the optical path. The illumination light is guided by the light guide 110 to the distal end of the electronic endoscope 100. The illumination light guided to the light guide 110 illuminates a living tissue 400 as an observation target (imaging target) via an illumination window 120 provided on a front surface of the distal end of the electronic endoscope 100.
[0022]
Illumination light illuminating the living tissue 400 is reflected by the living tissue 400 and enters the objective optical system 130 as observation light. The observation light emitted from the objective optical system 130 is bent by the optical path deflecting unit 140 in a direction orthogonal to the optical axis of the objective optical system 130, in other words, in a direction orthogonal to the longitudinal direction (insertion direction) of the electronic endoscope 100. .
[0023]
In the electronic endoscope 100 of the present embodiment, the solid-state imaging device 150 having a function of receiving observation light and performing photoelectric conversion to generate an image signal has a light receiving surface parallel to the longitudinal direction of the electronic endoscope 100. It is arranged so that it becomes. The solid-state imaging device 150 is, for example, a CCD.
[0024]
The observation light bent by the above-described optical path deflecting unit 140 forms an image on the light receiving surface of the solid-state imaging device 150 and is received by each of the plurality of light receiving elements arranged in a matrix on the light receiving surface. Is done. Since the living tissue 400 is illuminated by the intermittent illumination light that has been transmitted through the filters of the RGB rotation filters 220 in order as described above, the light receiving surface of the solid-state imaging device 150 intermittently transmits the observation light of each color. Are sequentially received.
[0025]
The driver 240 included in the processor 200 drives the solid-state imaging device 150 by a drive control signal transmitted from the timing generator 230. More specifically, the driver 240 performs a period during which the solid-state imaging device 150 receives any one of the R light, the G light, and the B light, based on the drive control signal transmitted from the timing generator 230. The solid-state imaging device 150 is driven to accumulate the observation light in each light receiving element, and the electric charge accumulated in each light receiving element during a period in which the solid-state imaging element 150 does not receive any observation light by the light blocking portion of the RGB rotation filter 220. The solid-state imaging device 150 is driven so as to output the image signal as an image signal.
[0026]
FIG. 2 is a side sectional view schematically showing an internal structure of a distal end portion of the electronic endoscope 100 according to the embodiment of the present invention. FIG. 2 shows the internal structure of the distal end of the electronic endoscope 100 in more detail than FIG. Hereinafter, the configuration and operation of the distal end portion of the electronic endoscope 100 will be described in more detail with reference to FIG.
[0027]
As described above, the observation light of the living tissue 400 incident via the objective optical system 130 is bent by the optical path deflecting unit 140 in a direction orthogonal to the longitudinal direction of the electronic endoscope 100. The optical path deflecting unit 140 is formed by bonding a first prism 142 and a second prism 144 together. These prisms are arranged in the longitudinal direction of the electronic endoscope 100 in the order of the first prism 142 and the second prism 144 from the objective optical system 130 side.
[0028]
The first prism 142 has a beam splitter 142a having a function of splitting light in the optical path of observation light obtained from the living tissue 400. The beam splitter 142a is arranged in a state of being inclined by 45 degrees with respect to the optical path of the observation light of the living tissue 400 that coincides with the optical axis of the objective optical system 130. In other words, the beam splitter 142a is arranged in a state of being inclined by 45 degrees with respect to the longitudinal direction of the electronic endoscope 100. Therefore, the observation light of the living tissue 400 that has entered the beam splitter 142a is partially bent (reflected) by 90 degrees, in a direction orthogonal to the longitudinal direction of the electronic endoscope 100, that is, to the solid-state imaging device 150. Then, a part of the light passes through the second prism 144 and travels along the longitudinal direction of the electronic endoscope 100.
[0029]
The second prism 144 has a total reflection mirror 144a having a function of totally reflecting light in an optical path of observation light transmitted through the beam splitter 142a. The total reflection mirror 144a is arranged in a state of being inclined by 45 degrees with respect to the optical path of the observation light transmitted through the beam splitter 142a that coincides with the optical axis of the objective optical system 130. In other words, the total reflection mirror 144a is arranged in a state of being inclined by 45 degrees with respect to the longitudinal direction of the electronic endoscope 100. Therefore, the observation light transmitted through the beam splitter 142a is bent 90 degrees by the total reflection mirror 144a, and travels in a direction orthogonal to the longitudinal direction of the electronic endoscope 100, that is, toward the solid-state imaging device 150.
[0030]
FIG. 3 is a top view schematically illustrating the configuration of the solid-state imaging device 150 provided in the distal end portion of the electronic endoscope 100 according to the embodiment of the present invention. The solid-state imaging device 150 includes a light receiving section 152 in which a plurality of light receiving elements are arranged in a matrix on a semiconductor substrate. The configuration and operation of the solid-state imaging device 150 will be described below with reference to FIG. The surface of the semiconductor substrate, which is the base of the solid-state imaging device 150, including the light receiving portion 152, that is, the light receiving surface has a side in the arrow X direction shown in FIG. It has a longer rectangular shape.
[0031]
The solid-state imaging device 150 includes a light receiving unit 152, a horizontal transfer unit 154, and an amplifier 156. As described above, since the electronic endoscope device 500 generates a color image by a frame sequential method, the solid-state imaging device 150 is a monochrome CCD. Further, in order to achieve a reduction in the diameter of the electronic endoscope 100, the solid-state imaging device 150 is a full-frame CCD having no storage unit.
[0032]
The light receiving section 152 has two image areas (imaging areas) of a light receiving section 152a and a light receiving section 152b. The light receiving section 152a is an image area for capturing the observation optical image reflected by the beam splitter 142a, and is arranged so as to coincide with the image forming plane of the observation optical image. The light receiving unit 152b is an image area for capturing the observation optical image reflected by the total reflection mirror 144a, and is arranged so as to coincide with the imaging plane of the observation optical image. That is, the light receiving unit 152a and the light receiving unit 152b are arranged side by side along the longitudinal direction of the electronic endoscope 100. In the light receiving sections 152a and 152b, the same number of light receiving elements are arranged at the same pitch in each of the arrow Y direction and the arrow X direction. That is, the light receiving unit 152a and the light receiving unit 152b are formed as light receiving units having the same shape and the same number of light receiving elements.
[0033]
Further, as described above, since the solid-state imaging device 150 is a full frame type CCD, the light receiving section 152 transfers the electric charge accumulated in each of the plurality of light receiving elements in the direction of arrow X in FIG. It has the function of Since the solid-state imaging device 150 is a small-sized chip, the light receiving unit 152a and the light receiving unit 152b are optically substantially equivalently arranged. Accordingly, subject images having substantially the same shape are formed on these two light receiving portions.
[0034]
FIG. 4 is a diagram schematically showing the relationship between the light receiving unit 152 and the image circle of the living tissue 400. As shown in FIG. FIG. 4A is a schematic diagram illustrating a relationship between the light receiving unit 152a and the image circle 410a. FIG. 4B is a schematic diagram illustrating a relationship between the light receiving unit 152b and the image circle 410b. FIG. 4C is a diagram schematically illustrating an observation image generated by performing an image synthesis process described later on the image signals of the light receiving units 152a and 152b. Hereinafter, the configuration and operation of the solid-state imaging device 150 will be described with reference to FIG. 4 in addition to FIGS. 2 and 3.
[0035]
FIG. 4A illustrates an image of the living tissue 400 incident on the light receiving unit 152a, that is, a positional relationship between the image circle 410a of the living tissue 400 connected by the objective lens 130 on the light receiving unit 152a and the light receiving unit 152a. It is a thing. In FIG. 4A, each of a plurality of hatched square portions indicates one of the light receiving elements included in the light receiving unit 152a. FIG. 4B illustrates an image of the living tissue 400 incident on the light receiving unit 152b, that is, a positional relationship between the image circle 410b of the living tissue 400 and the light receiving unit 152b that the objective lens 130 connects on the light receiving unit 152b. It is shown. In FIG. 4B, each of the plurality of square portions shown by oblique lines different from FIG. 4A and each of the plurality of square portions shown by white are light receiving portions provided in the light receiving portion 152b. Each of the elements is shown. Each of the light receiving elements included in these light receiving sections 152a and 152b is arranged at the same pitch p. The observation optical images formed by the image circle 410a and the image circle 410b are substantially the same observation image. Further, in FIG. 4, for simplicity of description, each of the light receiving sections is shown as having 16 light receiving elements, but these light receiving sections 152a and 152b are actually shown in FIG. It has more light receiving elements than the number shown.
[0036]
As shown in FIG. 4A, the light receiving section 152a has a non-light receiving portion composed of a region having no light receiving function between each of the plurality of light receiving elements. The center of the light receiving section 152a is located at a position corresponding to the non-light receiving section, that is, between the light receiving elements, and is located at a distance X from the center of each of the four light receiving elements disposed closest to the center of the light receiving section 152a. It is located at a position shifted by p / 2 in the direction and the Y direction, that is, in the middle. The image circle 410a of the living tissue 400 that is reflected by the beam splitter 142a via the objective lens 130 and travels toward the light receiving unit 152a is formed on the light receiving unit 152a such that the center 412a coincides with the center of the light receiving unit 152a. The mutual positional relationship between the objective lens 130, the beam splitter 142a, and the light receiving unit 152a is determined so as to be formed.
[0037]
Further, as shown in FIG. 4B, the light receiving section 152b has a non-light receiving portion composed of a region having no light receiving function between each of the plurality of light receiving elements. Similarly to the light receiving section 152a, the center 153b of the light receiving section 152b is also located at a position corresponding to the non-light receiving portion, that is, between the light receiving elements and the four light receiving elements disposed closest to the center 153b. It is located at a position shifted by p / 2 from the center in the X direction and the Y direction, that is, in the middle. The image circle 410b of the living tissue 400, which is bent by the total reflection mirror 144a via the objective lens 130 and travels, has the center 412b of any one of the light receiving elements arranged closest to the center 153b of the light receiving section 152b. The mutual positional relationship among the objective lens 130, the total reflection mirror 144a, and the light receiving unit 152b is determined so that the objective lens 130, the total reflection mirror 144a, and the light receiving unit 152b are formed on the light receiving unit 152b so as to coincide with the center.
[0038]
As described above, each image circle is formed at a relatively different position with respect to each light receiving unit. In addition, each image circle is formed at a position relatively shifted by p / 2 in the X direction and the Y direction with respect to each light receiving unit. Therefore, these light receiving units 152a and 152b can obtain an observation image of a portion corresponding to a non-light receiving portion of each other. Therefore, image processing described later is performed on the observation images obtained by the light receiving units 152a and 152b, and the observation images are superimposed so that the centers 412a and 412b, which are the centers of the respective image circles, coincide with each other. As shown in FIG. 4C, between the plurality of pixels imaged by each of the plurality of light receiving elements included in the light receiving section 152a, a plurality of light receiving sections included in the light receiving section 152b are provided. As each of a plurality of pixels imaged by each of the elements is located, an observation image of a large number of pixels, that is, an observation image of a large number of pixels, that is, an observation image of high pixels, Obtainable.
[0039]
As described above, the light receiving unit 152 and the optical path deflecting unit 140 are arranged so that each image circle is formed at a position relatively shifted by p / 2 in the X direction and the Y direction with respect to each light receiving unit. . In addition, the light receiving unit 152a and the light receiving unit 152b are arranged such that each of the light receiving elements is shifted by p / 2 in the X direction. Further, the beam splitter 142a and the total reflection mirror 144a are arranged so that the image circle is formed with a relative shift of p / 2 with respect to each light receiving unit in the Y direction. In other words, in other words with respect to the Y direction, the light receiving units 152a and 152b are arranged such that the image circle is formed with a p / 2 offset relative to each of the light receiving units.
[0040]
In another embodiment, the optical path deflecting unit 140 may be arranged so that each image circle is formed at a position shifted by p / 2 relative to each light receiving unit in the X direction and the Y direction. it can. In addition, the beam splitter 142a and the total reflection mirror 144a are arranged so that the image circle is formed at a position shifted by p / 2 relative to each light receiving unit in the X direction and the Y direction. That is, one of the beam splitter 142a and the total reflection mirror 144a bends the incident observation light by 90 degrees in a direction orthogonal to the longitudinal direction of the electronic endoscope 100, and simultaneously outputs the objective light when the observation light enters the light receiving unit 152. The lens 130 is arranged at an angle such that an image circle is formed around a position shifted by p / 2 in the X direction from the optical axis of the lens 130.
[0041]
The horizontal transfer unit 154 is a part to which charges accumulated in each of the plurality of light receiving elements included in the light receiving unit 152 are transferred, and is configured by charge coupled elements arranged in a line in the longitudinal direction of the semiconductor substrate. ing. The horizontal transfer unit 154 transfers the charge accumulated in the light receiving element included in the light receiving unit 152a, and the horizontal transfer unit 154a transfers the charge accumulated in the light receiving element included in the light receiving unit 152b. And a horizontal transfer unit 154b.
[0042]
Each of the charge coupled elements constituting the horizontal transfer unit 154 is arranged at the same pitch as the light receiving elements of the light receiving unit 152 in the arrow Y direction. The horizontal transfer unit 154a included in the horizontal transfer unit 154 includes a charge-coupled device that is arranged in alignment with each of the light receiving elements of the light receiving unit 152a in the arrow Y direction. The horizontal transfer unit 154b included in the horizontal transfer unit 154 includes a charge-coupled device that is arranged in alignment with each of the light-receiving elements of the light-receiving unit 152b in the arrow Y direction. Note that each of the charge-coupled devices constituting the horizontal transfer unit 154 has a larger allowable amount so that even if a plurality of light-receiving elements of the light-receiving unit 152 accumulate a plurality of light-receiving elements, they are not saturated. For this reason, it is formed larger than the light receiving element of the light receiving section 152 in the arrow X direction.
[0043]
The electric charge accumulated in each of the light receiving elements included in the light receiving unit 152a is sequentially transferred to the horizontal transfer unit 154a for each line of the light receiving elements in the arrow Y direction orthogonal to the arrow X direction. Further, the electric charges accumulated in each of the light receiving elements included in the light receiving section 152b are sequentially transferred to the horizontal transfer section 154b for each line of the light receiving elements in the arrow Y direction orthogonal to the arrow X direction. Then, the horizontal transfer unit 154 outputs the charge of each line transferred from the light receiving unit 152a and the light receiving unit 152b to the amplifier 156. The amplifier 156 amplifies the input charge and outputs the amplified charge to the first-stage video signal processing unit 250 provided in the processor 200.
[0044]
The image signal output from the solid-state imaging device 150 is transmitted to the processor 200 and subjected to image processing described later. The signals processed by the processor 200 are output to the monitor 300 as various video signals that can be displayed on an external device, and are displayed on the monitor 300 as a color observation image. Hereinafter, a process of image processing performed by the processor 200 will be described.
[0045]
The image signal of the living tissue 400 in the body cavity obtained by the solid-state imaging device 150 is transmitted to the first-stage video signal processing unit 250 provided in the processor 200. The first-stage video signal processing unit 250 amplifies the transmitted image signal and performs processing such as sampling and holding. Then, the image signal is converted into a digital signal. The converted digital signal is further switched in synchronization with the driving of the solid-state imaging device 150 by a multiplexer (not shown) included in the first-stage video signal processing unit 250 and separated into image signals of R, G, and B colors. Then, the data is output to each memory of the RGB memory 260a and the RGB memory 260b.
[0046]
The electronic endoscope 100 has a still image button 160. The still image button 160 is an operation button for switching a method of displaying an observation image on the monitor 300. When the still image button 160 is on, a still image to be observed can be displayed on the monitor 300. When the still image button 160 is off, a moving image to be observed can be displayed on the monitor 300.
[0047]
When the above-described still image button 160 is turned on, a signal indicating that the still image button 160 is turned on to the first stage video signal processing unit 250 via the system control 232 and the timing generator 230 provided in the processor 200. Enter. At this time, the first-stage video signal processing unit 250 outputs image signals of each color of R, G, and B to each of the RGB memory 260a and the RGB memory 260b. When the still image button 160 is off, the signal is not input to the first-stage video signal processing unit 250. At this time, the first-stage video signal processing unit 250 outputs image signals of each color of R, G, and B to each of the RGB memories 260a.
[0048]
The RGB memory 260a and the RGB memory 260b include R, G, and B memories (not shown) which are three frame memories corresponding to the respective colors of R, G, and B, and each of the colors separated by the first-stage video signal processing unit 250. Are stored in the corresponding frame memories. The image signal obtained by the light receiving unit 152a is input to the RGB memory 260a, and the image signal obtained by the light receiving unit 152b is input to the RGB memory 260b.
[0049]
When the still image button 160 is turned on, the timing generator 230 transmits a timing signal for simultaneously reading image signals stored in the frame memories of the RGB memory 260a and the RGB memory 260b. This timing signal is transmitted, for example, at a timing at which a moving image composed of 30 frames per second can be displayed on the monitor. That is, the timing generator 230 transmits a timing signal for simultaneously reading out image signals stored in the frame memories of the RGB memory 260a and the RGB memory 260b at 30 frames per second. Based on this timing signal, the image signals of each color stored in the RGB memory 260a and the RGB memory 260b are read out at the same time and output to the image synthesis processing unit 290.
[0050]
The image synthesis processing unit 290 captures the image information obtained by the light receiving unit 152a and the light receiving unit 152b with each of the plurality of light receiving elements included in the light receiving unit 152a, as illustrated in FIG. Between each of the plurality of pixels, such that each of the plurality of pixels imaged by each of the plurality of light receiving elements included in the second light receiving unit is positioned, and both image information are superimposed and synthesized, This is a signal processing unit that performs image synthesis for generating one still image. That is, the image synthesis processing unit 290 synthesizes the image signals of the respective colors read simultaneously from the RGB memory 260a and the RGB memory 260b as described above to generate a high-pixel still image. Further, the image synthesis processing unit 290 converts the synthesized image signal into an RGB video signal and outputs the RGB video signal to the monitor 300. When these video signals are output to the monitor 300, the observation image of the living tissue 400 is displayed on the monitor 300 as a color still image. Further, the image synthesis processing unit 290 can also output the synthesized image signal so that it can be recorded on another recording medium.
[0051]
When the still image button 160 is turned off, the timing generator 230 transmits a timing signal for simultaneously reading image signals stored in each frame memory of the RGB memory 260a. Based on this timing signal, the image signals of each color stored in the RGB memory 260a are simultaneously read and output to the subsequent signal processing unit 270.
[0052]
The subsequent signal processing unit 270 converts this signal into an analog signal, and further converts this analog signal into a composite video signal, a Y / C signal, and an RGB video signal for displaying on the monitor 300. Then, when these video signals are output to the monitor 300, the observation image of the living tissue 400 is displayed on the monitor 300 as a color moving image.
[0053]
FIG. 5 is a timing chart showing a period of imaging and transfer of the solid-state imaging device 150 when the still image button 160 is turned on, and a period of observation light incident on the solid-state imaging device 150. FIG. 5A is a timing chart for performing imaging and transfer of the solid-state imaging device 150, in which an accumulation period for accumulating electric charges and a transfer period for transferring electric charges corresponding to each accumulated color are alternately repeated. It has become. FIG. 5B is a timing chart showing the period of the observation light incident on the solid-state imaging device 150. The period in which the observation light of each color is incident and the observation light are blocked. The period is alternately repeated.
[0054]
As shown in FIG. 5, while the observation light of the R light of the living tissue 400 illuminated with the R illumination light is incident on the light receiving unit 152, the solid-state imaging device 150 receives the light of the light receiving unit 152a and the light receiving unit 152b. Each of the elements accumulates the charges generated by the observation light of the R light. When the observation light of the R light enters the light receiving unit 152a and the light receiving unit 152b for a certain period, the illumination light is shielded by the light blocking unit of the RGB rotation filter 220 for a certain period, and the observation light incident on the light receiving unit 152a and the light receiving unit 152b also changes. Cut off for a certain period. During a period in which the observation light does not enter the light receiving units 152a and 152b, the solid-state imaging device 150 horizontally transfers each of the charges due to the observation light of the R light accumulated in each of the light receiving elements of the light receiving units 152a and 152b. The data is transferred to the transfer unit 154a and the horizontal transfer unit 154b, respectively. These charges transferred to the horizontal transfer unit 154 are output from the amplifier 156 as image information of R light, and transmitted to the first-stage video signal processing unit 250.
[0055]
The solid-state imaging device 150 accumulates the charges due to the G light observation light in the same manner, and transfers the accumulated charges due to the G light observation light to the horizontal transfer unit 154. The charge transferred to the horizontal transfer unit 154 is output from the amplifier 156 as image information of G light, and transmitted to the first-stage video signal processing unit 250. Further, the solid-state imaging device 150 accumulates the charges by the observation light of the B light in the same manner, and transfers the accumulated charges by the observation light of the B light to the horizontal transfer unit 154. The charges transferred to the horizontal transfer unit 154 are output from the amplifier 156 as image information of B light, and transmitted to the first-stage video signal processing unit 250.
[0056]
As described above, by processing the image information of each of the R light, G light, and B light output from the amplifier 156 by the processor 200 as described above, one color still image is formed.
[0057]
FIGS. 5C, 5D, and 5E are timing charts showing in detail the transfer operation of the charge accumulated in the light receiving element during the period Tb in FIG. 5A. The period Tb indicates a period during which the charges accumulated by the observation light of the G light are transferred to the horizontal transfer unit 154 and output from the amplifier 156 as image information of the G light. FIG. 5C is a timing chart showing V1 signal pulses for sequentially transferring the charges accumulated in each of the light receiving elements of the light receiving section 152a to the horizontal transfer section 154a for each light receiving element in one line in the arrow Y direction. . FIG. 5D is a timing chart showing V2 signal pulses for sequentially transferring the charges accumulated in each of the light receiving elements of the light receiving section 152b to the horizontal transfer section 154b for each light receiving element in one line in the arrow Y direction. It is. FIG. 5E is a timing chart showing a pulse of an H signal for transferring the charges transferred to the horizontal transfer unit 154 in the horizontal direction of the horizontal transfer unit 154, that is, in the arrow Y direction.
[0058]
The period Tb is a period during which the still image button 160 is turned on, so that the charges accumulated in the light receiving units 152a and 152b are transferred. Therefore, the V1 signal is input to the light receiving unit 152a, and the V2 signal is input to the light receiving unit 152b. When the V1 signal is input to the light receiving unit 152a, all the electric charges stored in each of the light receiving elements of the light receiving unit 152a are shifted by one stage in the direction of the arrow X. When the V2 signal is input to the light receiving unit 152b, all the electric charges accumulated in each of the light receiving elements of the light receiving unit 152b are shifted by one stage in the direction of the arrow X. As a result, each of the electric charges accumulated in the light receiving element of one line of each of the light receiving units arranged closest to the horizontal transfer unit 154a and the horizontal transfer unit 154b shifts in the direction of the arrow X and shifts in the horizontal transfer unit. The charge is transferred to each of the charge-coupled devices 154a and the horizontal transfer unit 154b that match in the arrow Y direction.
[0059]
When charges are transferred from the light receiving units 152a and 152b to the horizontal transfer unit 154a and the horizontal transfer unit 154b by the V1 signal and the V2 signal, next, an H signal is input to the horizontal transfer unit 154, and the horizontal transfer unit 154a and The charges transferred to the horizontal transfer unit 154b are transferred in the direction of the arrow Y. That is, the charges transferred to the horizontal transfer unit 154 are swept out by the amplifier 156 and amplified, and transmitted to the first-stage video signal processing unit 250.
[0060]
The above-described series of operations in the period Tb is repeated until the charges of all lines accumulated in the light receiving units 152a and 152b are transmitted to the first-stage video signal processing unit 250. When the charges of all the lines are output from the amplifier 156, the transfer operation in the period Tb ends, and then, the accumulation operation of the observation light of B light starts.
[0061]
FIG. 6 is a timing chart showing a period of imaging and transfer of the solid-state imaging device 150 when the still image button 160 is off, and a period of observation light incident on the solid-state imaging device 150. FIG. 6A is a timing chart similar to FIG. 5A, and FIG. 6B is a timing chart similar to FIG. 5B.
[0062]
As shown in FIG. 6, during a period in which the observation light of the R light of the living tissue 400 illuminated with the R illumination light is incident on the light receiving unit 152, the solid-state imaging device 150 applies the light to each of the light receiving elements of the light receiving unit 152a. , And accumulates charges due to the observation light of the R light. When the R observation light is incident on the light receiving unit 152a for a certain period, the illumination light is shielded for a certain period by the light shielding unit of the RGB rotation filter 220, and the observation light incident on the light receiving unit 152a is also cut off for a certain period. During a period in which the observation light is not incident on the light receiving unit 152a, the solid-state imaging device 150 transfers each of the charges due to the observation light of the R light accumulated in each of the light receiving elements of the light receiving unit 152a to the horizontal transfer unit 154a. This charge transferred to the horizontal transfer unit 154 is output from the amplifier 156 as image information of R light, and transmitted to the first-stage video signal processing unit 250.
[0063]
The solid-state imaging device 150 accumulates the charges due to the G light observation light in the same manner, and transfers the accumulated charges due to the G light observation light to the horizontal transfer unit 154a. The charges transferred to the horizontal transfer unit 154a are output from the amplifier 156 as image information of G light, and transmitted to the first-stage video signal processing unit 250. Further, the solid-state imaging device 150 accumulates the charges by the observation light of the B light in the same manner and transfers the accumulated charges by the observation light of the B light to the horizontal transfer unit 154a. The charges transferred to the horizontal transfer unit 154a are output from the amplifier 156 as image information of B light, and transmitted to the first-stage video signal processing unit 250.
[0064]
As described above, the image information of each of the R light, the G light, and the B light output from the amplifier 156 is processed by the processor 200, so that a color image of one screen is formed. By repeating this operation, the image of the living tissue 400 is displayed on the monitor 300 as a moving image.
[0065]
FIGS. 6C, 6D, and 6E are timing charts showing in detail the transfer operation of the charge accumulated in the light receiving element during the period Ta in FIG. 6A. The period Ta indicates a period during which the charges accumulated by the observation light of the G light are transferred to the horizontal transfer unit 154 and output from the amplifier 156 as image information of the G light. 6 (c) is a timing chart similar to FIG. 5 (c), FIG. 6 (d) is a timing chart similar to FIG. 5 (d), and FIG. 6 (e) is a timing chart similar to FIG. 5 (e). It is a similar timing chart.
[0066]
Since the period Ta is when the still image button 160 is off, only the electric charge accumulated in the light receiving section 152a is transferred. Therefore, the V2 signal is not input to the light receiving unit 152b, and the V1 signal, which is a signal for the transfer operation, is input only to the light receiving unit 152a. When the V1 signal is input to the light receiving unit 152a, all the electric charges stored in each of the light receiving elements of the light receiving unit 152a are shifted by one stage in the direction of the arrow X. As a result, each of the electric charges accumulated in the light receiving element of one line arranged closest to the horizontal transfer unit 154a shifts in the direction of the arrow X so that the charge coupling coincides with the direction of the arrow Y of the horizontal transfer unit 154a. Transferred to each of the elements.
[0067]
When the charge is transferred from the light receiving unit 152a to the horizontal transfer unit 154a by the V1 signal, an H signal is input to the horizontal transfer unit 154, and the charge transferred to the horizontal transfer unit 154a is transferred in the direction of the arrow Y. . That is, the charges transferred to the horizontal transfer unit 154a are swept out by the amplifier 156, amplified, and transmitted to the first-stage video signal processing unit 250.
[0068]
The above-described series of operations in the period Ta is repeated until the charges of all the lines accumulated in the light receiving unit 152a are transmitted to the first-stage video signal processing unit 250. When the charges of all the lines are output from the amplifier 156, the transfer operation in the period Ta ends, and then, the accumulation operation of the observation light of B light starts.
[0069]
As described above, in the solid-state imaging device 150 of the present embodiment, the light receiving unit 152a and the light receiving unit 152b, which are two image areas, are arranged side by side along the longitudinal direction of the distal end of the electronic endoscope 100. ing. In the solid-state imaging device 150 of the present embodiment, the charge transfer path of the light receiving unit 152a and the light receiving unit 152b is formed by the horizontal transfer unit 154, which is a one-line charge-coupled device. Further, the horizontal transfer units 154 are arranged along the longitudinal direction of the distal end of the electronic endoscope 100. Therefore, by providing the solid-state imaging device 150 of the present embodiment, two light receiving sections can be provided without increasing the diameter of the electronic endoscope, and as a result, a high-quality observation image can be obtained.
[0070]
The above is the embodiment of the present invention. The present invention is not limited to these embodiments, and can be modified in various ranges.
[0071]
In the present embodiment, the image signals obtained from the two light receiving units are combined only when the image is a still image. However, the image signal may be combined when a moving image is obtained.
[0072]
【The invention's effect】
As described above, the solid-state imaging device of the present invention has the first light receiving unit and the second light receiving unit in different regions in the predetermined direction on a single semiconductor substrate formed long in the predetermined direction, Each of the light receiving elements is arranged so as to be shifted by a half of the pitch in a direction orthogonal to the predetermined direction. Therefore, even if this solid-state imaging device is incorporated in a cylindrical device, for example, an electronic endoscope, it does not increase the diameter or decrease the dynamic range, and does not allow each light-receiving unit to receive light from each other. An observation image of a portion corresponding to the portion can be generated. Such an observation image is generated by a device including an image processing unit, for example, an electronic endoscope device, between each of a plurality of pixels imaged by each of the plurality of light receiving elements of the first light receiving unit. Are synthesized so that each of the plurality of pixels imaged by each of the plurality of light receiving elements of the light receiving unit is located, thereby generating a high-quality observation image.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an electronic endoscope apparatus including an electronic endoscope according to an embodiment of the present invention.
FIG. 2 is a side sectional view schematically showing an internal structure of a distal end portion of the electronic endoscope according to the embodiment of the present invention.
FIG. 3 is a top view schematically illustrating a configuration of a solid-state imaging device provided in a distal end portion of the electronic endoscope according to the embodiment of the present invention.
FIG. 4 is a diagram schematically illustrating a relationship between a light receiving unit and an image circle.
FIG. 5 is a timing chart showing a period of imaging and transfer of the solid-state imaging device when a still image button is turned on, and a period of observation light incident on the solid-state imaging device.
FIG. 6 is a timing chart showing a cycle of imaging and transfer of the solid-state imaging device when a still image button is turned off, and a period of observation light incident on the solid-state imaging device.
[Explanation of symbols]
100 electronic endoscope
140 Optical path deflection unit
150 solid-state image sensor
152a, 152b light receiving unit
154a, 154b horizontal transfer unit
500 Electronic endoscope device

Claims (7)

A first light-receiving unit and a second light-receiving unit, in which a plurality of light-receiving elements are arranged in a matrix at a predetermined pitch in different regions in the predetermined direction on a single semiconductor substrate formed long in a predetermined direction. A solid-state imaging device having a light receiving portion,
Each of the plurality of light receiving elements included in the first light receiving unit and each of the plurality of light receiving elements included in the second light receiving unit are arranged in a direction orthogonal to the predetermined direction. A solid-state imaging device, wherein the device is arranged so as to be shifted by half the pitch. The solid-state imaging device further includes a charge-coupled device adjacent to the first light receiving unit and the second light receiving unit and arranged in a line in the predetermined direction,
A first transfer unit that is a transfer destination of the charge accumulated in the first light receiving unit;
The solid-state imaging device according to claim 1, further comprising: a second transfer unit that is a transfer destination of the charge accumulated in the second light receiving unit. An objective optical system for forming a subject image,
A first light-receiving unit and a second light-receiving unit, in which a plurality of light-receiving elements are arranged in a matrix at a predetermined pitch in different regions in the predetermined direction on a single semiconductor substrate formed long in a predetermined direction. A solid-state imaging device having a light receiving unit;
Light beam separation for separating the subject image toward the first light receiving unit and the second light receiving unit such that the subject image is formed in the first light receiving unit and the second light receiving unit. Means, and an electronic endoscope provided in the distal end portion,
The light beam separating means is configured to displace the subject image, which is shifted by a half of the pitch relative to each of the first light receiving unit and the second light receiving unit in the predetermined direction and a direction orthogonal to the predetermined direction. Guiding, an electronic endoscope. An objective optical system for forming a subject image,
A first light-receiving unit and a second light-receiving unit, in which a plurality of light-receiving elements are arranged in a matrix at a predetermined pitch in different regions in the predetermined direction on a single semiconductor substrate formed long in a predetermined direction. A solid-state imaging device having a light receiving unit;
Light beam separation for separating the subject image toward the first light receiving unit and the second light receiving unit such that the subject image is formed in the first light receiving unit and the second light receiving unit. Means, and an electronic endoscope provided in the distal end portion,
The solid-state imaging device such that each of the first light receiving unit and the second light receiving unit receives the subject image shifted by half the pitch relatively in the predetermined direction and a direction orthogonal to the predetermined direction. An electronic endoscope, wherein: 5. The electronic endoscope according to claim 3, wherein the solid-state imaging device is arranged so that a longitudinal direction of the semiconductor substrate and a longitudinal direction of the distal end portion match. 6. . The solid-state imaging device further includes a charge-coupled device adjacent to the first light receiving unit and the second light receiving unit and arranged in a line in the predetermined direction,
A first transfer unit that is a transfer destination of the charge accumulated in the first light receiving unit;
The electronic endoscope according to any one of claims 3 to 5, further comprising: a second transfer unit to which the charge accumulated in the second light receiving unit is transferred. An electronic endoscope according to any one of claims 3 to 6,
Between each of the plurality of pixels imaged by each of the plurality of light receiving elements included in the first light receiving unit, each of the plurality of light receiving elements included in the second light receiving unit A processor having a signal processing unit that synthesizes an image signal obtained from the first light receiving unit and the second light receiving unit, so that each of the plurality of imaged pixels is located; An electronic endoscope device characterized by the above-mentioned.

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