JP2011206077A - Imaging unit and endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging unit capable of further surely suppressing the formation of dew condensation on a cover glass attached to a solid-state image sensor; and to provide an endoscope.SOLUTION: This imaging unit includes: an objective optical system that imports light of an image of a subject; an image sensor that captures the light and outputs an imaging signal; the cover glass that is provided on an imaging surface of the image sensor and seals the image sensor airtightly; a prism that is disposed between the objective optical system and the cover glass so as to guide the light from the objective optical system to the imaging surface; and a heat-insulating layer that is formed between a light outgoing plane in the prism and a light incoming plane in the cover glass.

Description

  The present invention relates to an imaging apparatus and an endoscope.

  In the medical field, an endoscope is used for medical diagnosis. An imaging device having a solid-state imaging device such as a CCD is built in the distal end of the insertion portion that is inserted into the body cavity of the endoscope. The endoscope can process an image signal obtained from the solid-state image sensor with a processing device and observe an image in the body cavity with a monitor.

  An imaging device for an endoscope includes a solid-state imaging device and an objective optical system for capturing light incident from an observation window provided at the distal end of an insertion portion, and an air layer is separated on an imaging surface of the solid-state imaging device. A cover glass is arranged. In some imaging apparatuses, a prism for guiding incident light from an objective optical system to an imaging surface of a solid-state imaging device is provided on a cover glass.

  By the way, in an endoscope insertion part, a solid-state image sensor and its surrounding electronic parts become high temperature compared with the front-end | tip of an insertion part by drive heat. For this reason, when a temperature difference occurs between the outer surface that is the light incident side of the cover glass and the inner surface that is the surface on the side of the solid-state image sensor, moisture is contained in the space where the solid-state image sensor is sealed by the cover glass. Condensation may occur on the inner surface of the cover glass. In particular, when the observation window becomes dirty, water may be fed or blown at the distal end of the insertion portion, so that a temperature difference occurs between the distal end of the insertion portion and the insertion portion, and condensation tends to occur on the inner surface of the cover glass. . When dew condensation occurs on the inner surface of the cover glass, it is difficult to observe the image displayed on the monitor due to water droplets due to dew condensation.

  Patent Document 1 listed below describes an endoscope imaging apparatus configured to prevent moisture from being contained in a space in which a solid-state imaging device is sealed with a cover glass.

  Patent Document 2 listed below describes an imaging apparatus that can enhance the shielding effect against heat from the outside of a double cover glass by providing a double cover glass on the imaging surface of a solid-state imaging device.

JP 7-100102 A Japanese Patent No. 4179908

  In an endoscope having a prism provided between the objective optical system and the solid-state image sensor, the outer surface of the cover glass that seals the solid-state image sensor contacts the prism. On the light incident side of the prism, an objective optical system such as an objective lens disposed on the distal end side of the insertion portion of the endoscope is disposed. The temperature of the prism tends to be lower than the temperature of the solid-state imaging device inside the insertion portion and the vicinity thereof due to the influence of the objective optical system. As a result, a temperature difference occurs between the outer surface of the cover glass in contact with the prism and the inner surface on the solid-state imaging device side, which makes it difficult to eliminate the temperature difference.

  In any of the above-mentioned documents, there is no description about eliminating the temperature difference between the inner surface and the outer surface of the cover glass in the endoscope including the prism and the cover glass.

  An object of the present invention is to provide an imaging apparatus and an endoscope that can more reliably suppress the occurrence of condensation on a cover glass attached to a solid-state imaging device.

The present invention includes an objective optical system that captures light of a subject image;
An image sensor that images the light and outputs an image signal;
A cover glass provided on the imaging surface of the imaging device and hermetically sealing the imaging device;
A prism that is disposed between the objective optical system and the cover glass and guides light from the objective optical system to the imaging surface;
It is an imaging device having a heat insulating layer that is formed between the prism and the cover glass and suppresses heat from being transferred between the prism and the cover glass.

  In addition, the present invention is an endoscope in which the imaging device is built in an endoscope insertion portion.

  When driving the imaging device (when observing with an endoscope), the imaging element and its surroundings become hotter than the objective optical system due to driving heat. Then, heat is transmitted from the image sensor side on the inner surface of the cover glass on the image sensor side, and the temperature becomes high. In the imaging device, since the heat insulating layer is provided between the cover glass and the prism, it is possible to prevent heat from being transmitted between the cover glass and the prism. For this reason, it can suppress that a temperature difference arises between the outer surface by the side of the prism of a cover glass, and the inner surface by the side of a solid-state image sensor. Therefore, it is possible to suppress the occurrence of condensation on the cover glass.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device and endoscope which can suppress more reliably that dew condensation arises in the cover glass attached to the solid-state image sensor can be provided.

1 is an overall configuration diagram of an endoscope. FIG. It is a schematic external view in the front-end | tip part of an endoscope insertion part. It is sectional drawing in the AA arrow direction view of FIG. It is a disassembled perspective view of a heat insulation layer. It is typical sectional drawing which shows the modification of the endoscope shown in FIG.

FIG. 1 is an overall configuration diagram of an endoscope.
The endoscope 100 includes a main body operation unit 11 and an endoscope insertion unit 13 that is connected to the main body operation unit 11 and is inserted into a body cavity.

  The main body operation unit 11 includes angle knobs 23, 25, various buttons 27 such as an air / water supply button, a suction button, and a shutter button, a continuous unit 29 extended to the endoscope insertion unit 13 side, and a continuous unit 29. A provided forceps insertion portion 31 is provided. A universal cable 15 is connected to the main body operation unit 11.

  The endoscope insertion portion 13 includes a flexible portion 19, a bending portion 21, and a distal end portion 17 in order from the main body operation portion 11 side.

  The angle knobs 23 and 25 are used to perform an operation of driving to bend the bending portion 21 of the endoscope insertion portion 13 by rotating.

  The various buttons 27 are operated by the user in order to execute air / water supply, suction, imaging of the observation site, and the like at the distal end portion 17 of the endoscope insertion portion 13.

  The forceps insertion portion 31 has an opening for inserting a treatment instrument such as an inserted forceps, and the opening communicates with a later-described forceps opening formed at the distal end portion 17 of the endoscope insertion portion 13. Yes.

  The universal cable 15 is provided with a light guide connector (not shown) at its tip. The light guide connector is detachably connected to a light source device (not shown), whereby illumination light is sent to the illumination optical system of the distal end portion 17 of the endoscope insertion portion 13. In addition, an electrical connector is connected to the light guide connector, and this electrical connector is detachably coupled to a processor that performs image signal processing and the like.

  The flexible portion 19 is formed of a member that extends from the continuous portion 29 with a diameter smaller than that of the continuous portion 29 and is softer than the rigidity of the member that constitutes the continuous portion 29.

  The bending portion 21 is remotely bent by turning the angle knobs 23 and 25 of the main body operation portion 11. Thereby, the front-end | tip part 17 can be orient | assigned to a desired direction.

FIG. 2 is a schematic external view of the distal end portion of the endoscope insertion portion.
The distal end portion 17 of the endoscope insertion portion 13 is provided with an observation window 35 on the distal end surface 33, irradiation ports 37A and 37B of the illumination optical system, forceps port 39, and air / water supply nozzle 41 on both sides of the observation window 35. It has been.

  The observation window 35 takes in light from an observation site in the body cavity and guides it to an objective optical system in the distal end portion 17 described later.

  The irradiation ports 37A and 37B irradiate the observation site in the body cavity with light.

  The forceps port 39 leads out a treatment tool such as a forceps inserted from the forceps insertion portion 31 shown in FIG.

  The air / water supply nozzle 41 supplies air / water toward the observation window 35.

FIG. 3 is a cross-sectional view of the distal end portion of the endoscope shown in FIG.
The distal end portion 17 includes a distal end hard portion 43 made of a metal material such as a stainless steel material, an outer tube 63 that covers the outer periphery of the distal end hard portion 43, and a distal end cover 65 that covers the distal end side of the distal end hard portion 43. The outer tube 63 and the tip cover 65 are closely joined so that there is no water immersion inside the tip portion 17.

  In the distal end hard portion 43, a first drilling hole 43a and a second drilling hole 43b are formed. A lens barrel 45 that houses the observation window 35 exposed on the distal end surface of the distal end portion 17 and the objective lens 36 is fitted into the first drilling hole 43a. A metal forceps pipe 49 is fitted into the second drilling hole 43 b, and a forceps tube 51 made of a soft material is connected to the forceps pipe 49. The observation window 35 and the objective lens 36 constitute an objective optical system.

  In addition, an imaging device 50 including an objective lens 36, a prism 55, and an imaging element 59 is built in the distal end portion 17.

  The prism 55 is disposed on the optical axis extension of the objective lens 36 held in the lens barrel 45 in the internal space of the distal end portion 17. The prism 55 is a triangular prism, reflects light incident from the objective lens 36 side, and guides it to the imaging surface of the imaging element 59.

  The image sensor 59 is a CCD image sensor and is mounted on the circuit board 57. A transparent cover glass 71 is bonded to the light incident side of the circuit board 57 in order to hermetically seal the image sensor 59. The circuit board 57 is held in the internal space of the distal end portion 17 by the holding member 47. The circuit board 57 is connected to a signal cable 58 for outputting image information output from the image sensor 59 to a processor (not shown).

  The imaging device 50 forms an image of light taken from the objective lens 36 on the imaging element 59 mounted on the circuit board 57 via the prism 55, and outputs image information from the imaging element 59. The image information output from the imaging device 50 is signal-processed by the processor and displayed as an image on the monitor.

  Although not shown, an optical member such as a lens disposed in the irradiation ports 37A and 37B (see FIG. 2) and an illumination optical system including a light guide are disposed in the internal space of the endoscope distal end portion 17. .

  In the endoscope 100, the image sensor 59 and the circuit board 57 on which the image sensor 59 is mounted generate heat during endoscope observation. On the other hand, the temperature of the prism 55, the objective lens 36, and the observation window 35 tends to be lower than that of the image sensor 59 side. In particular, when water is supplied or blown when the observation window is dirty, the temperature is lower than that of the image sensor 59. Therefore, in order to suppress the occurrence of a temperature difference between the inside and the outside of the cover glass, a heat insulating layer is provided between the prism 55 and the cover glass 71 to prevent heat from being transmitted between the two. .

FIG. 4 is an exploded perspective view of the circuit board, the cover glass, and the heat insulating layer.
A cover glass 71, a spacer 73, and a heat insulating glass 75 are stacked and joined in this order on the circuit board 57 on which the image sensor 59 is mounted.
The heat insulating layer includes a substantially rectangular frame-shaped member spacer 73 bonded to the upper surface of the cover glass 71, and a transparent heat insulating glass 75 bonded to the cover glass 71 with the spacer 73 interposed therebetween. It has a sealed structure.

  The heat insulating layer may be an unsealed structure, that is, an air layer that ventilates the inside of the endoscope. If the heat insulation layer has an unsealed structure, the heat insulation layer becomes the air inside the endoscope, so the time for the saturated water vapor amount to reach saturation in the heat insulation layer becomes longer compared to the configuration in which the heat insulation layer is sealed. There is merit in.

  A gap is provided between the cover glass 71 and the heat insulating glass 75. The endoscope 100 transfers heat between the heat insulating layer and the prism 55 when the solid-state imaging device and its surroundings become high temperature during observation, but the gap between the prism 55 and the cover glass 71 is caused by a gap. , Heat is not transmitted directly. For this reason, the temperature difference between the space between the cover glass 71 and the solid-state imaging element 59 and the space between the cover glass 71 and the heat insulating glass 75 can be suppressed to be small. The temperature difference becomes smaller. Therefore, it is possible to suppress the occurrence of condensation on the cover glass 71.

  The spacer 73 is made of a heat insulating material. As a material of the spacer 73, for example, resin or silicon can be used. Use of silicon is particularly preferable from the viewpoints of adhesive strength and linear expansion coefficient.

  The heat insulating glass 75 is made of a heat insulating material. As a material of the heat insulating glass 75, quartz glass can be used. Quartz glass is preferable because it is hardly affected by heat and has a low coefficient of linear expansion. In addition, you may use normal glass as the glass 75 for heat insulation. Further, as the material of the heat insulating glass 75, the same glass as the cover glass 71 may be used.

  The space between the cover glass 71 and the heat insulating glass 75 is sealed, and may be a gas layer or a vacuum layer containing air, an inert gas, or the like.

  The heat insulating layer composed of the heat insulating glass 75 and the spacer 73 has a thermal conductivity of 0.2 W / m · K or less. It is preferable that materials for the heat insulating glass 75 and the spacer 73 are appropriately selected so as to satisfy the numerical value of the thermal conductivity. Moreover, it is preferable that the volume between the cover glass 71 and the heat insulating glass 75 is set so that the thermal conductivity is 0.2 W / m · K or less.

  In the above example, one heat insulating glass 75 is provided on the cover glass 71 via the spacer 73. However, another heat insulating glass is provided on the heat insulating glass 75 via the spacer. May be. In other words, the heat insulating layer may include a plurality of glasses laminated on the cover glass 71, a spacer that provides a gap between the cover glass and the heat insulating glass, and between the heat insulating glasses. Good. By carrying out like this, it can suppress more reliably that a temperature difference arises by the inner side and the outer side of a cover glass.

FIG. 5 is a schematic cross-sectional view showing a modification of the endoscope shown in FIG. In the following description, the members already described are denoted by the same reference numerals, and the description is simplified or omitted.
In this example, an optical film 77 which is a heat insulating layer is formed on the cover glass 71. The optical film 77 has one surface in contact with the light emission surface (lower surface in the drawing) of the prism 55 and the other surface in contact with the light incident surface (upper surface in the drawing) of the cover glass 71.

  In this configuration example, the endoscope 100 includes the prism 55 side and the cover glass 71 by the optical film 77 formed between the cover glass and the prism when the solid-state imaging device and its periphery become high during observation. The heat is prevented from being transmitted to and from. By doing so, it is possible to suppress the occurrence of a temperature difference between the outer surface and the inner surface of the cover glass 71 and to suppress the formation of condensation in the space sealed with the cover glass 71.

  As a material of the optical film 77, for example, PET (polyethylene terephthalate) or TAC (triacetyl cellulose) is used.

  The thermal conductivity of the optical film 77 is preferably 0.2 W / m · K or less.

The present specification discloses the following contents.
(1) an objective optical system that captures light of a subject image;
An image sensor that images the light and outputs an image signal;
A cover glass provided on the imaging surface of the imaging device and hermetically sealing the imaging device;
A prism that is disposed between the objective optical system and the cover glass and guides light from the objective optical system to the imaging surface;
An image pickup apparatus having a heat insulating layer that is formed between the prism and the cover glass and prevents heat from being transferred between the prism and the cover glass.
(2) The imaging apparatus according to (1),
The heat insulating layer, and heat insulating glass;
An imaging device including a spacer that provides a gap between the cover glass and the heat insulating glass, and is sealed.
(3) The imaging apparatus according to (1),
The heat insulating layer, and a plurality of heat insulating glasses;
The imaging device (4), (2), or (3) that includes and is sealed between the cover glass and the heat insulating glass and a spacer that provides a gap between the heat insulating glasses. An imaging device,
An imaging apparatus including a gas layer between the cover glass and the heat insulating glass.
(5) The imaging device according to (2) or (3),
An imaging device including a vacuum layer between the cover glass and the heat insulating glass.
(6) The imaging apparatus according to (1),
An imaging apparatus in which the heat insulating layer is an optical film.
(7) The imaging apparatus according to any one of (1) to (6),
The imaging device whose thermal conductivity of the said heat insulation layer is 0.2 W / m * K or less.
(8) An endoscope in which the imaging device according to any one of (1) to (7) is built in an endoscope insertion portion.

13 Insertion portion 17 Tip portion 50 Imaging device 73 Spacer 75 Heat-resistant glass 100 Endoscope

Claims (8)

An objective optical system that captures the light of the subject image;
An image sensor that images the light and outputs an image signal;
A cover glass provided on the imaging surface of the imaging device and hermetically sealing the imaging device;
A prism that is disposed between the objective optical system and the cover glass and guides light from the objective optical system to the imaging surface;
An image pickup apparatus, comprising: a heat insulating layer formed between the prism and the cover glass for suppressing heat from being transmitted between the prism and the cover glass. The imaging apparatus according to claim 1,
The heat insulating layer, and heat insulating glass;
An imaging device including a spacer that provides a gap between the cover glass and the heat insulating glass, and is sealed. The imaging apparatus according to claim 1,
The heat insulating layer, and a plurality of heat insulating glasses;
The imaging device which has the space | interval which provides a space | gap between the said cover glass and the said glass for heat insulation, and between the said glass for heat insulation, and is sealed. The imaging apparatus according to claim 2 or 3,
An imaging apparatus including a gas layer between the cover glass and the heat insulating glass. The imaging apparatus according to claim 2 or 3,
An imaging device including a vacuum layer between the cover glass and the heat insulating glass. The imaging apparatus according to claim 1,
An imaging apparatus in which the heat insulating layer is an optical film. The imaging device according to any one of claims 1 to 6,
The imaging device whose thermal conductivity of the said heat insulation layer is 0.2 W / m * K or less.   An endoscope in which the imaging device according to any one of claims 1 to 7 is built in an endoscope insertion portion.

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