JP4597642B2 - Imaging device for electronic endoscope - Google Patents

Description

  An objective optical system that is disposed at the distal end of the electronic endoscope and captures image light of the observation site in the living body, and an imaging surface that is parallel to the optical axis of the objective optical system is arranged by a prism. The present invention relates to an imaging apparatus for an electronic endoscope that includes an imaging element in which image light is guided to an imaging surface, and a cover glass is attached with a gap on the imaging surface.

  Conventionally, medical diagnosis using an electronic endoscope has been actively performed in the medical field. An electronic endoscope incorporates an image pickup device having an image pickup element such as a CCD at the tip thereof, and performs signal processing on the image pickup signal acquired by the CCD with a processor device, thereby allowing an image in a living body to be displayed on a monitor or the like. Can be observed.

  In the imaging apparatus for an electronic endoscope as described above, an objective optical system for capturing image light of an observation site in a living body is disposed at the distal end portion of the electronic endoscope, and the optical axis of the objective optical system is arranged. There is a type in which the CCD is arranged so that the imaging surface is parallel, and image light is guided to the imaging surface by a prism. In this type of electronic endoscope imaging apparatus, the dimension (thickness) in the direction perpendicular to the optical axis of the imaging apparatus itself directly affects the radial dimension of the electronic endoscope. For this reason, conventionally, various attempts have been made to reduce the thickness of the electronic endoscope by reducing the thickness of the imaging device as much as possible (see Patent Documents 1 to 3).

  In Patent Document 1, a CCD is placed on the top surface, and has a bottom substrate provided with an extension region extending in a predetermined direction, and a storage hole that overlaps the top surface of the bottom substrate and forms a storage portion for the CCD. And an extension portion reinforcing substrate provided with an extension portion region extending in a predetermined direction, the thickness of the bottom substrate is less than 0.5 mm, and the extension portion regions of both substrates are overlapped in one direction from the side surface. There has been proposed a CCD package in which an extending portion extending in the direction is formed and a terminal portion is provided on the extending portion. According to this CCD package, the connection pin that has been projected to the lower side of the conventional package becomes unnecessary, and the signal line can be wired using the upper space of the extending portion, so that the thickness of the entire package is reduced. can do.

  In Patent Document 2, a TAB (Tape Automated Bonding) method is used to form a conductor lead on the CCD terminal so as to protrude from the outer periphery of the CCD, dispose the CCD in the opening of the circuit board, and place the conductor lead on the circuit board terminal. An endoscope imaging apparatus that eliminates the need for a CCD package by being connected to is proposed.

Patent Document 3 proposes a camera head device for an electronic endoscope in which an empty area in which no terminal is arranged is set in the middle of the connection terminal row on the upper surface of the CCD, and a holding member for the objective optical system is arranged close to the empty area. Has been. According to this electronic endoscope camera head device, it is not necessary to arrange the holding member of the objective optical system by avoiding the bonding wire used for terminal connection, and the electronic endoscope is provided by the amount that the holding member of the objective optical system is arranged close to the electronic endoscope. The diameter of the mirror can be reduced.
Japanese Patent No. 2853939 Japanese Patent No. 3364574 Japanese Patent No. 3186965

  However, in the techniques described in Patent Documents 1 and 3, since the CCD is mounted on the substrate, the thickness increases by the amount of the substrate. In addition, Patent Document 1 uses a plurality of substrates having special shapes, and Patent Document 3 has to consider the layout of terminals in order to provide an empty area, which increases the component cost. There's a problem.

  On the other hand, since the technique described in Patent Document 2 eliminates the need for a CCD package, the problem of increasing the thickness of the substrate as in Patent Documents 1 and 3 is solved, but the CCD is disposed on the circuit board. There is a problem that the cost of parts is increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an imaging apparatus for an electronic endoscope capable of realizing a reduction in the diameter of the electronic endoscope at a low cost with a simple configuration. To do.

  In order to achieve the above object, the present invention provides an objective optical system that is disposed at the distal end of an electronic endoscope and captures image light of an observation site in a living body, and an imaging surface on the optical axis of the objective optical system. Are arranged so as to be parallel to each other, and the image light is guided to the imaging surface by the prism, and an imaging device having a cover glass attached with a gap on the imaging surface In the imaging apparatus, as the imaging element, a bare chip in which signal terminals are concentratedly arranged on a side edge on the rear end side of the insertion portion of the surface provided with the imaging surface is used, and the thickness is substantially equal to that of the bare chip. In addition, a circuit board in which signal terminals to be connected to signal terminals of the bare chip by wire bonding are concentratedly attached to the edge part on the distal end side of the insertion part is attached to the bare chip.

It is preferable that a conductive plate for electrically connecting the bare chip and the circuit board is attached from the back surface of the bare chip to the back surface of the circuit board. Moreover, it is preferable that the said conductive plate has lateral width of 1/4 or more of the said bare chip, and is arranged near one side of the back surface of the said bare chip and the said circuit board. Furthermore, it is preferable that a drive control signal for an electronic shutter is input to the image sensor via the conductive plate.

  According to the electronic endoscope imaging apparatus of the present invention, the signal terminals are arranged in a concentrated manner on the edge of the electronic endoscope insertion portion rear end side of the surface provided with the imaging surface as the imaging element. A circuit board that uses a bare chip and has a thickness approximately the same as that of the bare chip and in which signal terminals that are connected to the signal terminals of the bare chip by wire bonding are concentrated on the edge of the insertion section is attached to the bare chip. Therefore, it is possible to reduce the diameter of the electronic endoscope at a low cost with a simple configuration.

  In FIG. 1, an electronic endoscope apparatus 2 includes an electronic endoscope 10, a processor device 11, a light source device (not shown), and the like. The electronic endoscope 10 includes an insertion portion 12 that is inserted into a living body, an operation portion 13 that is connected to a proximal end portion of the insertion portion 12, and a cord 14 that is connected to the processor device 11 and the light source device. ing. The operation unit 13 is provided with a forceps port 15 through which a treatment tool is inserted. In addition, an imaging device 16 (see FIG. 2) for in-vivo imaging is built in the distal end portion 12a provided continuously with the distal end of the insertion portion 12.

  The processor device 11 is equipped with a signal processing circuit that performs various signal processing on the image pickup signal acquired by the image pickup device 16, and the light source device is equipped with a light source that supplies illumination light to the electronic endoscope 10 through the code 14. The in-vivo image captured by the imaging device 16 can be observed by the monitor 17.

  In FIG. 2, an observation window 20 is provided at the distal end portion 12a. The observation window 20 is provided with a lens barrel 22 that holds an objective optical system (lens group) 21 for capturing image light of an observation site in the living body. The lens barrel 22 is attached so that the optical axis 21 a of the objective optical system 21 is parallel to the central axis 12 b of the insertion portion 12.

  Connected to the rear end of the lens barrel 22 is a prism 24 that guides the image light of the observation site via the objective optical system 21 to the CCD 23 via the lens barrel holding frame 22a. The prism 24 is connected to a cover glass 26 described later. Thereby, the optical axis 21a of the objective optical system 21 and the imaging surface 23a of the CCD 23 are arranged in parallel. Although not shown, the distal end portion 12a is provided with an illumination window for irradiating the observation site in the living body with illumination light from the light source device, a forceps outlet communicating with the forceps port 15, and the like. .

  The CCD 23 is composed of, for example, an interline CCD, and a bare chip having an imaging surface 23a provided on the surface 23b is used. As shown in FIG. 3, a rectangular plate-like cover glass 26 is attached on the imaging surface 23 a of the CCD 23 via a square frame-like spacer 25. The CCD 23, the spacer 25, and the cover glass 26 are assembled by being bonded to each other with an adhesive.

A circuit board 27 having a thickness substantially equal to that of the CCD 23 is bonded to the rear end surface of the CCD 23 with an adhesive. A conductive plate 28 is attached with silver paste from the back surface 23 c of the CCD 23 to the back surface 27 a of the circuit board 27. The conductive plate 28 electrically connects the CCD 23 and the circuit board 27 through a through hole (not shown). An electronic shutter drive control signal, for example, an overflow drain control signal, is input to the CCD 23 via the conductive plate 28.

In order to mechanically reinforce the adhesion between the CCD 23 and the circuit board 27, the conductive plate 28 has a lateral width d1 of ¼ or more of the lateral width d2 of the CCD 23, and is made of a material excellent in heat dissipation, such as a copper plate. Become. The conductive plate 28 is formed with a thickness of about 0.2 mm.

Terminals 29 are concentrated on the edge 23 d of the rear end side of the insertion portion 12 on the surface 23 b of the CCD 23. On the other hand, on the circuit board 27, the terminals 30 are concentratedly arranged on the edge portion 27b on the distal end side of the insertion portion 12 facing the edge portion 23d. The terminal 29 and the terminal 30 are electrically connected by a bonding wire 31. An input / output terminal 33 to which a signal line 32 for inputting / outputting various signals to / from the processor device 11 via the cord 14 is soldered on the rear end side of the terminal 30 of the circuit board 27.

  The terminals 29 and 30 and the bonding wire 31 are sealed with a sealing agent 34. Further, in order to ensure the airtightness of the gap between the CCD 23 formed by the spacer 25 and the cover glass 26, a sealing agent 35 is applied so as to cover the end surfaces of the spacer 25 and the cover glass 26. The sealing agents 34 and 35 are made of, for example, a one-component curable epoxy resin.

The sealant 35 bonds the CCD 23 to which the cover glass 26 is attached via the spacer 25 and the circuit board 27, connects the terminal 29 and the terminal 30 with the bonding wire 31, and connects the terminal 29 with the sealant 34. 30 and the bonding wire 31 are applied after sealing.

Next, a manufacturing procedure of the imaging device 16 according to the above embodiment will be described. First, the cover glass 26 is attached on the image pickup surface 23 a of the CCD 23 via the spacer 25.

After the cover glass 26 is attached, the circuit board 27 is bonded to the rear end surface of the CCD 23. Next, the terminal 29 and the terminal 30 are connected by the bonding wire 31, and the terminals 29, 30 and the bonding wire 31 are sealed by the sealing agent 34. And the sealing agent 35 is apply | coated so that the end surface of the spacer 25 and the cover glass 26 may be covered.

After applying the sealing agent 35, the conductive plate 28 is moved to one side of the CCD 23 and the back surface of the circuit board 27 and suspended. At this time, the CCD 23 and the circuit board 27 are electrically connected by the conductive plate 28 through the through holes provided in the CCD 23 and the circuit board 27. Finally, a cover glass 26 is attached to the prism 24 connected to the lens barrel holding frame 22a with an adhesive.

The imaging device 16 manufactured as described above is built in the distal end portion 12a of the insertion portion 12 of the electronic endoscope 10, and the electronic endoscope 10 is connected to the light source device and the processor device 11 via the cord 14 and inserted. The unit 12 is inserted into the living body, and an image of the observation site in the living body by the imaging device 16 is observed on the monitor 17.

As described above, as the CCD 23, a bare chip in which the terminals 29 are concentrated on the edge portion 23d on the rear end side of the insertion portion 12 of the surface 23b on which the imaging surface 23a is provided is used, and at the edge portion 23d. Since the circuit board 27 in which the terminals 30 connected to the terminals 29 by wire bonding are concentratedly arranged on the edge portion 27b on the distal end side of the opposite insertion portion 12 is attached to the CCD 23, as shown in FIG. The thickness d3 from the cover glass 26 to the cover glass 26 can be made extremely small.

Further, the thickness of the main part of the image pickup device 16 is the sum of the thicknesses of the CCD 23, the cover glass 26, and the conductive plate 28, which are bare chips at most. Also good. Furthermore, the imaging device 16 can be manufactured with parts that can be formed by simple processing without manufacturing a specially shaped substrate as in the prior art. Therefore, it is possible to reduce the diameter of the electronic endoscope at a low cost with a simple configuration.

Further, since the conductive plate 28 is suspended over the CCD 23 and the back surfaces 23c and 27a of the circuit board 27, the adhesion between the CCD 23 and the circuit board 27 is mechanically reinforced, and the CCD 23 and the circuit board are driven when the CCD 23 is driven. The heat generated at 27 is efficiently radiated to the outside through the conductive plate 28.

The lateral width d1 of the conductive plate 28 may be equal to or greater than 1/4 of the lateral width d2 of the CCD 23, and may be substantially equal to the lateral width d2 of the CCD 23.

In the above embodiment, the spacer 25 is used to make a gap between the CCD 23 and the cover glass 26, but a transparent adhesive may be used instead of the spacer 25, and legs are formed on the cover glass 26. May be.

In the above-described embodiment, the so-called direct-view electronic endoscope 10 that is attached so that the optical axis 21a of the objective optical system 21 is parallel to the central axis 12b of the insertion portion 12 has been described as an example. The present invention can be applied to a side-view type electronic endoscope as long as the optical axis 21a of the objective optical system 21 and the imaging surface 23a of the CCD 23 are arranged in parallel. is there.

It is the schematic which shows the structure of an electronic endoscope apparatus. It is an expanded partial sectional view which shows the structure of the insertion part front-end | tip of an electronic endoscope. It is a disassembled perspective view which shows the structure of CCD, a spacer, a cover glass, and a circuit board.

Explanation of symbols

2 Electronic Endoscope 10 Electronic Endoscope 11 Processor Device 12 Insertion Unit 12a Tip 16 Imaging Device 23 CCD
23a Image pickup surface 23d Edge 26 Cover glass 27 Circuit board 27b Edge 28 Conductive plate 29, 30 Terminal 31 Bonding wire 34, 35 Sealant

Claims (3)

An objective optical system that is disposed at the distal end of the electronic endoscope and captures image light of the observation site in the living body, and an imaging surface that is parallel to the optical axis of the objective optical system is arranged by a prism. In an imaging apparatus for an electronic endoscope comprising: an imaging element in which the image light is guided to the imaging surface, and a cover glass is attached with a gap on the imaging surface;
As the imaging element, using a bare chip in which signal terminals are concentratedly arranged on the edge part on the rear end side of the insertion part of the surface provided with the imaging surface,
A circuit board having a thickness substantially equal to that of the bare chip, in which signal terminals connected to the signal terminals of the bare chip by wire bonding are concentrated on the edge portion on the distal end side of the insertion portion, is attached to the bare chip ,
A conductive plate for electrically connecting the bare chip and the circuit board is attached from the back side of the bare chip to the back side of the circuit board.
The conductive plate has a narrower lateral width than the bare chip, the bare chip and the electronic endoscope imaging apparatus characterized by being arranged close to one side of the back surface of the circuit board. The imaging apparatus for an electronic endoscope according to claim 1, wherein the circuit board is bonded to a rear end surface of the bare chip, and the conductive plate is attached so as to straddle the bonded portion. The conductive plate via the electronic endoscope imaging apparatus according to claim 1 or 2 drive control signal of the electronic shutter in the image pickup device is characterized in that the input.

Images