WO2017183152A1

WO2017183152A1 - Imaging device and endoscope device

Info

Publication number: WO2017183152A1
Application number: PCT/JP2016/062630
Authority: WO
Inventors: 芳郎西村
Original assignee: オリンパス株式会社
Priority date: 2016-04-21
Filing date: 2016-04-21
Publication date: 2017-10-26

Abstract

This imaging device 1 comprises: optical systems 33, 37 for producing an image of an object; a solid-state imaging element 40 for receiving the image of the object produced by the optical systems 33, 37 on a planar imaging surface 43 and performing photoelectric conversion; and a cover glass 41 disposed on the front face of the solid-state imaging element 40. The solid-state imaging element 40 is disposed so that the imaging surface 43 is oriented at a predetermined angle which does not include right and parallel angles relative to the imaging optical axis of the optical systems 33, 37. All side faces 41a, 41b of the cover glass 41 are parallel to the imaging optical axis O.

Description

Imaging apparatus and endoscope apparatus

The present invention relates to an imaging apparatus provided with an image sensor for detecting a subject and an endoscope apparatus equipped with the imaging apparatus.

An electronic device equipped with an imaging module for capturing an optical image that can be introduced from the outside of the living body or structure in order to observe difficult places such as the inside of the living body or the inside of the structure. Endoscopes are used, for example, in the medical field or the industrial field.

An imaging apparatus for an electronic endoscope includes an objective lens that forms a subject image, and a solid-state imaging device that is an image sensor such as a CCD sensor or a CMOD sensor disposed on the imaging surface of the objective lens.

Such an image pickup apparatus includes, for example, a vertically arranged structure in which a solid-state image pickup element described in Japanese Patent Application Laid-Open No. 2005-95432 is perpendicular to the photographing optical axis, A horizontal arrangement is known in which a solid-state imaging device is made parallel to a photographing optical axis by using a prism as described in Japanese Laid-Open Patent Publication.

However, recent solid-state image pickup devices have increased in outer dimensions due to an increase in the number of pixels and the like, and when used in electronic endoscopes, the solid-state image pickup devices are arranged vertically as described in Japanese Patent Application Laid-Open No. 2005-95432. If it is placed, there is a problem that the distal end portion of the insertion portion becomes thick.

Also, as described in Japanese Patent Application Laid-Open No. 2012-71064, there is a problem that when the solid-state imaging device is placed horizontally, the hard length of the distal end portion of the insertion portion is extended.

As described above, in the endoscope, when the solid-state imaging device is placed vertically, the hard length of the distal end portion of the insertion portion can be shortened, but the diameter is increased, and when placed horizontally, the distal end portion of the insertion portion is narrowed. Although the diameter can be increased, the hard length becomes longer, and there is a trade-off relationship.

Therefore, the present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an imaging apparatus and an endoscope that prevent an increase in size even when a solid-state imaging device becomes large due to an increase in the number of pixels. Is to provide a device.

An imaging apparatus according to one embodiment of the present invention includes an optical system that forms a subject image, a solid-state imaging element that receives and photoelectrically converts the subject image formed by the optical system on a planar imaging surface, and the solid-state imaging A cover glass disposed on the front surface of the element, wherein the solid-state image sensor is disposed such that the image pickup surface has a predetermined angle that does not include orthogonal and parallel to the photographing optical axis of the optical system. In addition, all the side surfaces of the cover glass are parallel to the photographing optical axis.

An endoscope apparatus according to an aspect of the present invention includes an optical system that forms a subject image, a solid-state imaging element that receives and photoelectrically converts the subject image formed by the optical system on an imaging surface that is a plane, A cover glass disposed on a front surface of the solid-state imaging device, wherein the solid-state imaging device is disposed with a predetermined angle that the imaging surface does not include orthogonal and parallel to the imaging optical axis of the optical system In addition, an imaging device in which all side surfaces of the cover glass are parallel to the imaging optical axis is mounted on the distal end portion of the insertion portion.

According to the present invention described above, it is possible to realize an imaging apparatus and an endoscope apparatus that prevent an increase in size even if the solid-state imaging device becomes large due to an increase in the number of pixels.

The top view which shows the structure of the endoscope system which concerns on 1 aspect of this invention. The figure which shows the cross section of the front-end | tip part of an endoscope apparatus together with an external device and an image display part similarly The figure which shows the cross section of the front-end | tip part of the endoscope apparatus of the state which the movement lens holding frame moved back with the external apparatus and the image display part similarly The figure which shows the cross section of the front-end | tip part of an endoscope apparatus with the external apparatus and image display part of a 1st modification similarly. The figure which shows the cross section of the front-end | tip part of an endoscope apparatus with the external apparatus and image display part of a 2nd modification similarly. The figure which shows the cross section of the front-end | tip part of the endoscope apparatus of the state which the solid-state image sensor holding frame moved ahead with the external apparatus and image display part of the 2nd modification similarly. The schematic diagram which shows the solid-state image sensor with respect to the depth of field in the objective optical system which concerns on a 3rd modification, and a depth of focus.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the drawings used for the following description, the scale of each component is made different in order to make each component recognizable on the drawing. It is not limited only to the quantity of the component described in (1), the shape of the component, the ratio of the size of the component, and the relative positional relationship of each component. Moreover, in the following description, the up-down direction seen toward the paper surface of the figure may be described as the upper part and the lower part of the component.
1 is a perspective view showing a configuration of an endoscope system according to one embodiment of the present invention, FIG. 2 is a view showing a cross section of a distal end portion of an endoscope apparatus together with an external apparatus and an image display section, and FIG. 3 is an external view. It is a figure which shows the cross section of the front-end | tip part of the endoscope apparatus of the state which the moving lens holding frame moved back with the apparatus and the image display part.

First, with reference to FIG. 1, an example of a configuration of an endoscope apparatus including an imaging apparatus 1 according to the present invention will be described.
An endoscope apparatus (hereinafter abbreviated as “endoscope”) 101 as an endoscope system of the present embodiment can be introduced into a subject such as a human body and optically transmits a predetermined observation site in the subject. It has a configuration for imaging.

Note that the subject into which the endoscope 101 is introduced is not limited to a human body, and may be another living body or an artificial object such as a machine or a building.

The endoscope 101 includes an insertion portion 102 introduced into the subject, an operation portion 103 located at the proximal end of the insertion portion 102, and a universal cord 104 extending from a side portion of the operation portion 103. It is mainly composed.

The insertion portion 102 includes a distal end portion 110 disposed at the distal end, a bendable bending portion 109 disposed on the proximal end side of the distal end portion 110, and an operation portion 103 disposed on the proximal end side of the bending portion 109. A flexible tube portion 108 having flexibility is connected to the tip end side of the tube.

The endoscope 101 may have a form called a so-called rigid endoscope that does not include a flexible portion in the insertion portion 102.

The distal end portion 110 is provided with an imaging device 1 described later. In addition, the operation unit 103 is provided with an angle operation knob 106 for operating the bending of the bending unit 109.

At the proximal end of the universal cord 104, an endoscope connector 105 connected to the external device 120 is provided. The external device 120 to which the endoscope connector 105 is connected is connected to an image display unit 121 such as a monitor via a cable.

The imaging cable 115 is configured to electrically connect the endoscope connector 105 and the imaging device 1. By connecting the endoscope connector 105 to the external device 120, the imaging device 1 is electrically connected to the external device 120 via the imaging cable 115.

The power supply from the external device 120 to the imaging device 1 and the communication between the external device 120 and the imaging device 1 are performed via the imaging cable 115.

The external device 120 is provided with an image processing unit 120a and a lens drive control unit 120b. The image processing unit 120 a generates a video signal based on the image sensor output signal output from the imaging device 1 and outputs the video signal to the image display unit 121.

That is, in the present embodiment, an optical image (endoscopic image) captured by the imaging device 1 is displayed on the image display unit 121 as a video.

Also, the lens drive control unit 120b drives and controls an actuator for driving a movable lens (described later) provided in the imaging apparatus 1. The lens drive control unit 120b is connected to an air tube (not shown here) as a control cable described later inserted into the universal cord 104, the operation unit 103, and the insertion unit 102.

Note that the endoscope 101 is not limited to the configuration connected to the external device 120 or the image display unit 121, and may be configured to include a part or all of the image processing unit or the monitor, for example.

Further, an illumination window (not shown), which will be described later, is provided at the distal end portion 110, and an LED illumination (not shown), for example, is used as a light source here on the back side of the illumination window. Is arranged.

The illumination means of the endoscope 101 is not limited to LED illumination, but employs an illumination optical fiber (light guide bundle) to transmit illumination light from a light source unit provided in the external device 120. It is good also as a structure.

Next, the configuration of the distal end portion 110 provided in the insertion portion 102 of the endoscope 101 will be described. In the following description, the object side direction (left side in each figure) toward the subject may be referred to as the front end or the front, and the opposite image side direction may be referred to as the base end or the rear.

As shown in FIG. 2, the tip portion 110 is provided with a tip constituent portion 21 that is a metal block, and the imaging device 1 and the LED illumination 24 are fitted to the tip constituent portion 21.

The distal end component 21 is provided with a distal end cover 22 that constitutes the distal end surface, and an illumination window 23 that emits illumination light of the observation window 31 and the LED illumination 24 of the imaging device 1 so as to be exposed by the distal end cover 22. These optical systems are arranged.

A reinforcing frame 26 is fitted to the outer peripheral portion of the proximal end of the distal end constituting portion 21, and an outer skin 27 that covers the distal end constituting portion 21 together with the reinforcing frame 26 is disposed.

The LED illumination 24 is fitted to the tip constituting portion 21 on the back side of the illumination window 23 via the LED holding frame 28. A wiring 25 for supplying power is extended from the LED illumination 24.

Although not shown, the wiring 25 is inserted into the insertion unit 102, the operation unit 103, and the universal cord 104, and is disposed up to the endoscope connector 105. The LED illumination 24 is driven to turn on when electric power is supplied to the wiring 25 from the external device 120 to which the endoscope connector 105 is connected via the electrical contact of the endoscope connector 105.

Next, the configuration of the imaging apparatus 1 according to the present embodiment will be described in detail below.
As shown in FIG. 2, the imaging apparatus 1 includes a lens holding frame 32 that is a first fixed lens frame, a front group lens 33 that is configured by a plurality of objective optical systems that are held by the lens holding frame 32, and a lens. And a lens frame 34 that is a second fixed lens frame fitted to the holding frame 32.

The imaging apparatus 1 is provided with a moving lens holding frame 36 that is a moving lens unit that moves back and forth within the lens frame 34, and a moving lens 37 that is an objective optical system is held on the moving lens holding frame 36. Yes.

A solid-state image sensor holding frame 38 is fitted behind the lens frame 34, and a solid-state image sensor 40 such as a CCD or CMOS is fixed to a cover glass 41 held by the solid-state image sensor holding frame 38. Has been.

The solid-state image sensor 40 is electrically connected to an image sensor substrate 42 on which electronic components and the like are mounted. An image pickup cable in which a plurality of wires as external signal lines are connected to the image sensor substrate 42 and the plurality of wires are collected. 115 extends rearward.

The imaging cable 115 is electrically connected to the external device 120 via the endoscope connector 105 (see FIG. 1, not shown in FIG. 2), and the imaging signal photoelectrically converted by the solid-state imaging device 40 is inside the external device 120. To the image processing unit.

A tubular member is fitted behind the solid-state image sensor holding frame 38, and a heat shrinkable tube is covered so as to cover the distal end portion of the imaging cable 115 together with the tubular member. Are provided for watertight shading (both not shown).

In this case, the rear base end surface of the cover glass 41 is cut at a predetermined angle θ of about 30 ° to 60 ° with respect to the photographing optical axis O, and the base end surface serves as an imaging surface of the solid-state imaging device 40. The light receiving surface 43 is bonded with a transparent resin.

In other words, the solid-state imaging device 40 is disposed such that the light receiving surface 43 is tilted at a predetermined angle θ of about 30 ° to 60 ° that does not include vertical (orthogonal) and horizontal (parallel) with respect to the photographing optical axis O. Has been. Here, the predetermined angle θ is set to 45 °.

Further, the upper surface 41 a and the lower surface 41 b that are the side surfaces of the cover glass 41 and the upper surface 40 a and the lower surface 40 b that are the side surfaces of the solid-state imaging device 40 have surfaces parallel to the imaging optical axis O. In this way, by making the side surface of the cover glass 41 and the side surface of the solid-state imaging device 40 parallel to the photographing optical axis O, the light rays in the peripheral portion among the light rays related to the formation of the subject image are covered. The glass 41 and the solid-state image sensor 40 are not damaged by the side surfaces, and the shooting angle of view is not narrowed. The cover glass 41 has all side surfaces around the photographing optical axis O parallel to the photographing optical axis O.

By the way, the imaging apparatus 1 of the present embodiment is provided with an actuator 50 that drives the moving lens holding frame 36 forward and backward.

The actuator 50 is an air cylinder held by an actuator holding frame 55 fixed to the solid-state image sensor holding frame 38, and is disposed in the cylinder tube 51, the piston rod 52, and the cylinder tube 51. And a piston 53 connected to the rod base end of the rod.

The piston rod 52 is configured to be able to advance and retreat together with the piston 53 in the cylinder tube 51, and the rod tip is connected to an arm portion 36a protruding from a part of the outer periphery of the moving lens holding frame 36 by press fitting, screwing or the like.

The arm portion 36a is engaged in a groove portion 55a formed in the actuator holding frame 55, and is guided straight when the moving lens holding frame 36 moves forward and backward.

An air tube 56 is connected to the base end of the cylinder tube 51, and compressed air is taken in and out through the air tube 56.

Although not shown, the air tube 56 is inserted into the insertion portion 102, the operation portion 103, and the universal cord 104, and is disposed up to the endoscope connector 105.

The air tube 56 is connected to the external device 120 via the endoscope connector 105, and compressed air is input / output (supply / exhaust) from the lens drive control unit 120b provided with a compressor, an electromagnetic valve, and the like.

Thereby, the actuator 50 increases and reduces the pressure in the cylinder pipe 51, so that the piston 53 moves back and forth, and drives the moving lens holding frame 36 connected to the piston rod 52 back and forth.

The actuator 50 has a distance range calculated by a cosine function of the predetermined angle θ of the solid-state imaging device 40 and the length of the inclined light receiving surface 43 in the vertical direction (Lcos θ when the length L of the light receiving surface 43 is assumed). Then, the movable lens holding frame 36 is driven forward and backward.

In the imaging apparatus 1 of the present embodiment configured as described above, the actuator 50 is driven and controlled in accordance with the reading timing of the subject image received by the solid-state imaging device 40, as shown in FIGS. .

As a specific example, the solid-state imaging device 40 inclined at a predetermined angle θ with respect to the photographing optical axis O of the subject reads light received by the light receiving surface 43 by a horizontal charge transfer method.

In the image processing unit 120a, the charges of one or a plurality of columns of pixels read out by the solid-state imaging device 40 are sequentially input as imaging signals through the imaging device substrate 42.

At this time, a control signal is output from the image processing unit 120a to the lens drive control unit 120b. Based on this control signal, compressed air is sucked and exhausted by the lens drive control unit 120b, and the movable lens holding frame 36 is driven back and forth by a predetermined distance by the actuator 50.

That is, the actuator 50 is driven and controlled in accordance with the timing at which the charges of pixels in one column or a predetermined plurality of columns read out by the solid-state imaging device 40 are read out.

Then, the image processing unit 120 a accumulates sequentially input charges, synthesizes pixels in all areas of the light receiving surface 43 of the solid-state imaging device 40, generates a subject image, and outputs the subject image to the image display unit 121.

As another example, the solid-state imaging device 40 tilted at a predetermined angle θ with respect to the photographic optical axis O of the subject simultaneously collects charges obtained by photoelectrically converting all areas of the light receiving surface 43 that is one frame. And output as an imaging signal to the image processing unit 120a.

When an imaging signal is input to the image processing unit 120a, a control signal is input from the image processing unit 120a to the lens drive control unit 120b. Based on this control signal, compressed air is taken in and out by the lens drive control unit 120b. Thus, the moving lens holding frame 36 is driven back and forth by a predetermined distance by the actuator 50.

That is, the actuator 50 is driven and controlled in accordance with the timing when the charges of the pixels in all areas read by the solid-state imaging device 40 are read.

Then, the image processing unit 120a accumulates a plurality of images based on the input imaging signal, cuts out (extracts) a focused portion from the plurality of images, and obtains one subject image. Generated and output to the image display unit 121.

Note that when the subject observes the blood vessel wall or may be a still image, the moving lens holding frame 36 need not be driven many times because only one subject image needs to be acquired.

Therefore, a switch for switching between the moving image mode and the still image mode may be provided in the operation unit 103 of the endoscope 101.

As described above, the imaging apparatus 1 according to the present embodiment is large in size due to an increase in the number of pixels and the like by providing the solid-state imaging device 40 with a predetermined angle θ with respect to the imaging optical axis O of the subject. Even when the solid-state imaging device 40 is mounted, the enlargement in the outer diameter direction and the longitudinal axis direction (direction along the photographing optical axis O) is prevented as compared with the conventional structure such as the vertical installation or the horizontal installation. can do.

As a result, the distal end portion 110 of the insertion portion 102 of the endoscope 101 on which the imaging apparatus 1 is mounted can be prevented from becoming a large diameter or the hard length can be increased, and the distal end portion 110 can be increased in size. Can be prevented.

Furthermore, in the imaging apparatus 1 of the present embodiment, all the side surfaces including the upper surface 41a and the lower surface 41b of the cover glass 41 and the upper surface 40a and the lower surface 40b of the solid-state imaging device 40 arranged with a predetermined angle θ are provided. Since the surface is parallel to the photographing optical axis O, the light receiving surface 43 of the solid-state imaging device 40 can make the most effective use of the region (area) where reflected light (photographing light) from the subject can be received. can do.

In this way, by making the side surface of the cover glass 41 parallel to the photographing optical axis O, the light rays in the peripheral portion among the light rays related to the formation of the subject image can be cast by the cover glass 41. The shooting angle of view is not narrowed.

In addition, although the actuator 50 illustrated the structure of the air cylinder, it is not limited to this, A liquid is used instead of compressed air, a servo motor, a stepping motor, a linear motor, a hydraulic cylinder, an electrostatic actuator, a piezoelectric Of course, it can be diverted as long as it uses elements, shape memory alloys, or the like, or drives the movable lens holding frame 36 forward and backward.

(First modification)
FIG. 4 is a diagram illustrating a cross-section of the distal end portion of the endoscope apparatus together with the external device and the image display unit of the first modified example.

Note that the cover glass 41 may have a plate shape having a predetermined uniform width dimension in which the upper surface 41a and the lower surface 41b have surfaces parallel to the photographing optical axis O, as shown in FIG.

(Second modification)
FIG. 5 is a diagram showing a cross section of the distal end portion of the endoscope apparatus together with the external device and the image display unit of the second modified example, and FIG. 6 is a solid-state imaging together with the external device and the image display unit of the second modified example. It is a figure which shows the cross section of the front-end | tip part of the endoscope apparatus in the state which the element holding frame moved ahead.

As shown in FIGS. 5 and 6, the imaging apparatus 1 of the present modification is configured to advance and retract a solid-state image sensor holding frame 38 that holds the solid-state image sensor 40 and the like by an actuator 50.

Specifically, the solid-state image sensor holding frame 38 here is disposed in the lens frame 34 so as to be able to advance and retract. The actuator 50 is connected by press-fitting, screwing, or the like to the arm portion 38a protruding from a part of the outer periphery of the solid-state image sensor holding frame 38 at the rod end of the piston rod 52.

The arm portion 38a is engaged in a groove portion 34a formed in the lens frame 34, and is guided straight when the solid-state image sensor holding frame 38 moves forward and backward.

Therefore, the actuator 50 drives the solid-state image sensor holding frame 38 connected to the piston rod 52 back and forth by increasing and decreasing the pressure in the cylinder tube 51 by sending and discharging compressed air from the lens drive control unit 120b.

The actuator 50 has a distance range calculated by a cosine function of the predetermined angle θ of the solid-state imaging device 40 and the length of the inclined light receiving surface 43 in the vertical direction (Lcos θ when the length L of the light receiving surface 43 is assumed). Then, the solid-state image sensor holding frame 38 is driven back and forth.

Other components are the same as those in the above embodiment. Also in this modification, the actuator 50 is driven and controlled in accordance with the reading timing of the subject image received by the solid-state imaging device 40, and the subject image is output from the image processing unit 120a to the image display unit 121.

The configuration of such an imaging apparatus 1 can also be configured to have the same operational effects as the above-described embodiment.

(Third Modification)
FIG. 7 is a schematic diagram illustrating a solid-state imaging device with respect to the depth of field and the depth of focus in the objective optical system according to the third modification.

In addition, as shown in FIG. 7, by disposing the solid-state imaging device 40 having a predetermined angle θ with respect to the imaging optical axis O of the subject within the depth of focus by the lens design of the objective optical system 60, The moving lens holding frame 36 that holds the moving lens 37 or the solid-state imaging device holding frame 38 that holds the solid-state imaging device 40 or the like need not be driven forward and backward, and the actuator 50 that drives them need not be provided.

In addition, by using the autofocus function mounted on the conventional imaging device, a moving lens holding frame 36 that holds the moving lens 37 or a solid-state imaging device holding frame 38 that holds the solid-state imaging device 40 is newly provided. There is no need to drive back and forth, and it is only necessary to provide the solid-state imaging device 40 having a predetermined angle θ with respect to the imaging optical axis O of the subject.

The embodiment and each modification described above may be combined with each other. That is, the invention described in the above-described embodiment is not limited to the embodiment and modification examples, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the described requirements can be deleted if the stated problem can be solved and the stated effect can be obtained. The configuration can be extracted as an invention.

Claims

An optical system for forming a subject image;
A solid-state imaging device that receives and photoelectrically converts a subject image formed by the optical system on a planar imaging surface; and
A cover glass disposed in front of the solid-state image sensor;
The solid-state imaging device is disposed such that the imaging surface has a predetermined angle that does not include orthogonal and parallel to the imaging optical axis of the optical system,
All the side surfaces of the cover glass are surfaces parallel to the photographing optical axis.
A moving lens frame that movably holds at least a part of the lenses of the optical system;
An actuator for advancing and retracting the moving lens frame;
The imaging apparatus according to claim 1, further comprising:
A solid-state image sensor holding frame for holding the solid-state image sensor;
An actuator for advancing and retracting the solid-state image sensor holding frame;
The imaging apparatus according to claim 1, further comprising:
4. The image pickup apparatus according to claim 2, wherein the actuator is driven and controlled in accordance with a timing of reading out charges of one or more columns of pixels of the solid-state image pickup device.
4. The imaging apparatus according to claim 2, wherein the actuator is driven and controlled in accordance with a timing of reading out charges of pixels in all areas of the solid-state imaging device.
The imaging apparatus according to any one of claims 1 to 5, wherein the solid-state imaging device has upper and lower surfaces parallel to the imaging optical axis.
An endoscope apparatus in which the imaging device according to any one of claims 1 to 6 is mounted at a distal end portion of an insertion portion.