JPH0621899B2 - Endoscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an endoscope for observing or photographing the state of a body cavity or internal organs by inserting a cable into the body cavity, for example.

(Prior Art) Conventionally, an endoscope has been used as an instrument for observing or photographing the state of a body cavity or internal organs by inserting a cable into the body cavity, for example.

In recent years, a fiberscope has come to be used as such an endoscope.

For example, such a fiberscope is formed by bundling optical fibers, arranging an image forming lens at the tip cross section, and arranging the tip of the optical fiber for a light guide in the vicinity thereof. Then, the inside of the body cavity is illuminated by the optical fiber for the light guide, and the reflected light is condensed by the lens to form an image on the cross section of the optical fiber bundle. Further, this output image is observed through the eyepiece lens.

However, according to an endoscope using such a fiberscope, (a) the resolution is 30,000 to 40,000 pixels, which is extremely low.

(B) Deterioration due to bending of the optical fiber, resulting in a life of 2 to
It is as short as 3 years.

(C) It cannot be directly taken out as a TV signal.

There are problems such as.

Therefore, in recent years, an endoscope of a type using a solid-state image pickup device in an image pickup section has been developed. According to this, there are advantages that the resolution is high, the life is long, and the image information can be directly taken out as a television signal.

By the way, according to such a solid-state image pickup device-mounted endoscope, it is necessary that the connecting portion between the image pickup means having the solid-state image pickup device and a cable for connecting to the outside has flexibility. Therefore, it is conceivable to use a flexible wiring board for this portion.

(Problems to be Solved by the Invention) However, since this flexible wiring substrate is required to have durability against repeated bending of tens of thousands of times, it is required to widen its wiring pattern. That is, at present, the width of the wiring pattern and the gap between the wiring patterns are limited to 100 to 150 μm, and the wiring area width of at least the number of signal wirings × 200 to 300 μm must be secured according to the number of signal wirings. I have to. Therefore, this may affect the outer diameter dimension of the envelope in which the flexible wiring board or the like is built, which may hinder the reduction in the diameter of the envelope.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an endoscope having excellent bending resistance and capable of reducing the diameter of an envelope.

[Structure of the Invention] (Means for Solving Problems) That is, the endoscope of the present invention is configured such that an envelope and an external light to be imaged are disposed inside one side of the envelope. A lens system to be taken in, a mirror arranged inside the envelope for folding the imaged light taken in by the lens system by approximately 90 °, and a mirror arranged inside the envelope and folded at 90 ° by the mirror. In an endoscope including an image pickup means for taking in imaged light, the image pickup means is arranged so as to cover a chip carrier, a solid-state image pickup element mounted on the chip carrier, and the solid-state image pickup element. It has a metal cap with a glass window that hermetically seals the solid-state image pickup device, and a metal frame arranged along the outer periphery of the metal cap, and the image pickup means attaches two flexible wiring boards. And processing the image pickup signal from the solid-state image pickup device. Is characterized in that circuit elements are mounted on the mounted flexible wiring board.

(Operation) In the endoscope of the present invention, since the flexible wiring board is formed by adhering two flexible wiring boards, the flexible wiring board is excellent in bending resistance and is flexible. Becomes narrower, and the diameter of the envelope can be reduced.

(Example) Hereinafter, the detail of the Example of this invention is described based on drawing.

FIG. 1 is a diagram showing an endoscope system according to an embodiment of the present invention.

In the figure, reference numeral 1 is a system main body, to which a cable 3 having a hard, cylindrical envelope 2 having an imaging unit or the like as an endoscope built in at its tip is connected. There is.

The system body 1 is equipped with a color CRT monitor 1a, a data input keyboard 1b, etc., and also has a control / processing unit, a Xe lamp light source, a frame memory, and a record photograph 35 mm
It has a built-in camera.

The inside of the envelope 2 has the structure shown in FIG.

That is, as shown in the figure, a lens system 4 for taking in external imaged light into the envelope 2 is disposed substantially at the center of the side surface of the tip of the envelope 2. Further, at a predetermined position on the optical axis of the lens system 4, a mirror 5 that returns the imaged light captured by the lens system 4 by about 90 ° is arranged. Further, on the optical axis bent 90 ° by the mirror 5, an image pickup means 6 for taking in the imaged light and converting the optical signal into an electric signal is arranged.

3 to 5 are views for explaining the above-mentioned image pickup means 6 in more detail.

In these figures, reference numeral 7 is a chip carrier,
A solid-state image sensor 8 is mounted on the chip carrier 7. A metal cap 9 with a glass window that hermetically seals the solid-state image sensor 8 is arranged so as to cover the solid-state image sensor 8. A metal frame 10 is arranged along the outer periphery of the metal cap 9 with a glass window.

The image pickup means 6 having such a structure is provided in order to obtain a noise margin of a transistor and a plurality of resistor chips which form an emitter follower circuit for impedance-converting an image pickup signal which is an electric signal from the solid-state image pickup element 8 and a power supply line. Are fixed on a flexible wiring board 12 on which circuit elements 11 such as a plurality of decoupling capacitors are mounted, and a joint portion between the chip carrier 7 and the flexible wiring board 12 is sealed with an organic insulating resin 13. Has been done.

The chip carrier 7 is made of a ceramic base such as alumina. Then, on the outer periphery of the surface of the chip carrier 7, Kovar, Fe having a coefficient of thermal expansion for welding with the metal cap 9 with a glass window is almost equal to that of the ceramic base.
A metal ring 14 made of / Ni42 alloy or the like is fixed by an adhesive such as Ag low. Also, the chip carrier 7
Inside the surface, a die bonding pad 15 for mounting the solid-state image sensor 8 is formed, and a wire bonding pad 16 is formed. The wire bonding pad 16 and a predetermined pad of the solid-state image sensor 8 are bonded to each other. It is electrically connected by a wire 17. Further, the back surface of the chip carrier 7 is electrically connected to the wire bonding pad 16 and is electrically connected to the flexible wiring substrate 12 by an adhesive such as solder.
8 is formed.

The metal cap 9 with a glass window is a low melting point glass made of transparent glass 20 having a matched coefficient of thermal expansion in a cap-shaped metal frame body 19 made of Kovar, Fe / Ni42 alloy or the like having a thermal expansion coefficient substantially equal to that of the chip carrier 7. It has a structure fixed by an adhesive such as. And the transparent glass 20
Anti-reflective coating layer (not shown) on both sides
Further, an infrared cut filter (not shown) is formed on the back surface of the transparent glass 20.

The metal frame 10 has a projecting portion 22 having a through hole 21 formed therein, and a screw 23 is passed through the through hole 21 of the projecting portion 22 to be screwed into a predetermined position of the envelope 2. The metal frame 10, that is, the image pickup means 6 is fixed to the envelope 2 (see FIG. 2).

The flexible wiring board 12 is the sixth in the semi-finished product state.
The structure is shown in FIGS.

That is, the flexible wiring board 12 has a structure in which the first flexible wiring board 12a shown in FIG. 6 and the second flexible wiring board 12b shown in FIG. As shown in FIG. 8, the width is narrowed at the position where the tip carrier 7 is mounted, and widened from the position where the circuit element 11 is mounted to the rear thereof.

In the narrow position where the chip carrier 7 of the first flexible wiring board 12a shown in FIG.
The conductor pattern 24 is exposed and solder-plated at a position corresponding to a part of the conductor pad 18 formed on the back surface. In the narrow position where the circuit element 11 is mounted, the conductor pads 25, 26 and 27 are exposed and solder-plated at positions corresponding to the mounted transistors, resistor chips and decoupling capacitors, respectively. There is. Furthermore, at the end of the wide position from the position where the circuit element 11 is mounted to the rear of the position, the second
The exposed conductor pad 28 for connection, which is electrically connected to the flexible wiring board 12b, is exposed, a through hole 28a is formed in the center thereof, and these are plated with solder. Also,
On the first flexible wiring board 12a, the wiring pattern 2 that electrically connects the conductor pattern 24, the conductor pads 25, 26, 27, and the exposed exposed conductor pads 28 for connection.
9 is formed, and an insulating film (not shown) made of polyimide or the like is formed thereon.

On the other hand, in the narrow position where the chip carrier 7 of the second flexible wiring board 12b shown in FIG. 7 is mounted, it is located at a position corresponding to a part of the conductor pad 18 formed on the back surface of the chip carrier 7. Each of the conductor patterns 30 is exposed and is solder-plated. The cable 3 connected to the system main body 1 is provided at a narrow position corresponding to the position where the circuit element 11 of the first flexible wiring board 12a is mounted.
A conductor pad 31 that is electrically connected to and fixed to a terminal (not shown) of a signal transmission cable therein by an adhesive such as solder is exposed and is plated with solder. Furthermore, in the wide position corresponding to the position where the exposed connection conductor pad 28 of the first flexible wiring substrate 12a is exposed, the exposed connection conductor pad 2 of the first flexible wiring substrate 12a is connected.
The exposed exposed conductor pads 32 for connection electrically connected to the conductors 8 are exposed and are plated with solder. Further, the conductor input / output pad 33 is exposed and solder-plated at the end of the wide position extending from this position to the rear. further,
On the second flexible wiring board 12b, these conductor patterns 30, conductor pads 31, and exposed conductor pads 3 for connection are provided.
2. A wiring pattern 34 for electrically connecting the conductor input / output pads 33 is formed, and an insulating film (not shown) such as polyimide is formed on the wiring pattern 34.

Then, the first flexible wiring board 12a and the second flexible wiring board 12b are arranged so that their back surfaces face each other as shown in FIG. 6 and FIG. Wiring board 1
The conductor patterns 24 and 30 of the second flexible wiring board 12b and the second flexible wiring substrate 12b are connected to the conductor pads 18 formed on the back surface of the chip carrier and the exposed conductor pads 28 and 32 for connection by soldering, respectively, and It is worn.

According to the flexible wiring board 12 having such a structure,
In this state, the second flexible wiring board 12b of the flexible wiring board 12 is assembled into the structure shown in FIGS.
It is possible to perform a functional test in a semi-finished product state by electrically connecting the conductor input / output pad 33 formed at the end of the item (3) to a testing device through an existing connector or the like. Then, the product can be put into a product state by cutting and removing a wide position of the flexible wiring substrate 12 from the position where the circuit element 11 is mounted to the rear thereof. That is, in the state of the product,
By connecting the conductor pad 31 of the second flexible wiring board 12b and the terminal (not shown) of the signal transmission cable in the cable 3 connected to the system body 1, the image pickup means 6 and the system body 1 are connected. Will be done.

Next, the configuration of the envelope 2 other than the image pickup section will be described with reference to FIG.

As shown in the figure, a forceps port for introducing forceps from the outside, which is connected to the outside via a cable 3, is provided around the lens system 4 arranged substantially in the center of the tip side surface of the envelope 2. 35, an air supply port 36 for sending air from the outside,
Water outlet 37 for sending water from the outside and external X
An illumination port 38 for irradiating the light from the e-lamp is arranged on the side facing the image pickup means 6.

However, according to the endoscope having such a structure, since the solid-state image pickup device 8 is used in the image pickup section, the resolution is about 100,000 pixels, which is extremely high. Also, in this case, since image information can be directly taken out as a television signal, diagnosis by a large number of people, treatment by collaborative work, education for medical students, observation with still images, storage in recording media, facilitation of image processing It will be possible to exchange information online and offline between hospitals.

Further, since the video signal from the endoscope to the main body system 1 is sent out as an electric signal via the cable 3, it is not necessary to use the cable 3 such as an optical fiber which is deteriorated by bending. Further, the solid-state imaging device 8 has a structure in which it is hermetically sealed by a metal cap 9 with a glass window,
That is, since it has a hermetic seal structure,
It is possible to prevent the solid-state image sensor 8 from being deteriorated by moisture. Thus, the endoscope having such a structure can secure a long life.

Furthermore, since the flexible wiring board 12 has a structure in which the first flexible wiring board 12a and the second flexible wiring board 12b are adhered to each other, a required wiring pattern can be obtained. It can be divided into these, and the wiring region width can be reduced. As a result, the width of the flexible wiring board 12 can be reduced, the envelope 2 can be reduced in diameter, and the operability can be improved and the burden on the patient can be reduced. In addition, the flexible wiring board 12 having the two-layer structure is also excellent in bending resistance, which leads to improvement of reliability and extension of life of the endoscope.

[Advantages of the Invention] As described above, according to the endoscope of the present invention, it is possible to achieve excellent bending resistance and to reduce the diameter of the envelope.

[Brief description of drawings]

FIG. 1 is a perspective view showing an endoscope system according to an embodiment of the present invention, FIG. 2 is a sectional view showing the structure of the endoscope shown in FIG. 1, and FIG. 4 is a plan view showing the image pickup means in the mirror, FIG. 4 is a front sectional view of FIG. 3, FIG. 5 is a side sectional view of FIG. 3, and FIG. 6 is a first flexible wiring board of this embodiment. FIG. 7 is a plan view showing the second flexible wiring board of this embodiment, FIG. 8 is a plan view showing the flexible wiring board of this embodiment, and FIG. 9 is FIG. It is a figure which shows the structure other than the imaging part of the endoscope shown in FIG. 1 ... System main body 2 ... Enclosure 3 ... Cable 4 ... Lens system 5 ... Mirror 6 ... Imaging device 7 ... Chip carrier 8 ... Solid-state imaging device 9 ... Metal cap with glass window 10 ... Metal frame 11 Circuit element 12 Flexible wiring board 12a First flexible wiring board 12b Second flexible wiring board

Claims (10)

[Claims] 1. An envelope, a lens system which is arranged on one side surface of the envelope and takes in external light to be imaged inside the envelope, and a lens system which is arranged inside the envelope and is taken by the lens system. An endoscope comprising: a mirror for folding back the captured imaged light by approximately 90 °; and an image pickup means disposed inside the envelope for capturing the imaged light folded back at 90 ° by the mirror. The means includes a chip carrier, a solid-state imaging device mounted on the chip carrier, a metal cap with a glass window arranged to cover the solid-state imaging device and hermetically sealing the solid-state imaging device, and a metal cap of the metal cap. A metal frame arranged along the outer periphery, wherein the imaging means comprises two flexible wiring boards attached to each other, and a circuit element for processing an imaging signal from the solid-state imaging element is provided. Be mounted on the mounted flexible wiring board An endoscope characterized by. 2. A chip carrier is made of a ceramic base, and a metal ring having a coefficient of thermal expansion approximately the same as that of the ceramic base for welding with a metal cap is fixed to the outer periphery of the surface, and inside the surface. A die bonding pad for mounting the solid-state imaging device and a wire bonding pad for electrically connecting to the solid-state imaging device are formed, and a conductor for electrically connecting to the flexible wiring board on the back surface thereof. The endoscope according to claim 1, wherein a pad is formed. 3. A metal cap with a glass window has a structure in which transparent glass having a matched coefficient of thermal expansion is fixed in a cap-shaped metal frame body having a coefficient of thermal expansion substantially equal to that of a chip carrier. The endoscope according to claim 1. 4. The endoscope according to claim 3, wherein antireflection coating layers are formed on both front and back surfaces of the transparent glass. 5. The endoscope according to claim 3, wherein an infrared cut filter is formed on the back surface of the transparent glass. 6. The endoscope according to claim 1, wherein the metal frame has a protruding portion having a through hole. 7. The endoscope according to claim 1, wherein a joint portion between the chip carrier and the flexible wiring board is sealed with an organic insulating resin. 8. A transistor, wherein a circuit element for processing an image pickup signal from a solid-state image pickup element mounted on a flexible wiring board forms an emitter follower circuit for impedance-converting an image pickup signal from the solid-state image pickup element, and The endoscope according to claim 1, comprising a plurality of resistance chips and a plurality of decoupling capacitors for obtaining a noise margin of a power supply line. 9. One of the flexible wiring boards, which is formed by adhering two flexible wiring boards to each other, is electrically connected to a conductor pad formed on the back surface of the chip carrier and protruding in an exposed state. Electrically connected conductor pattern, an exposed conductor pad on which a circuit element for processing an image pickup signal from the solid-state image pickup element is mounted, and an exposed conductor for connection electrically connected to the other flexible wiring board. A pad and a wiring pattern for electrically connecting these pads, and the other flexible substrate is a conductor pattern electrically projecting in an exposed state and electrically connected to a conductor pad formed on the back surface of the chip carrier. , An exposed conductor pad electrically connected to the signal transmission cable, an exposed conductor pad for connection electrically connected to one of the flexible wiring boards, and a conductor insert for facilitating connection with the test apparatus. Output pad and The claims, characterized by comprising between al and an electrically conductive and thereby the wiring pattern 1
The endoscope according to the item. 10. The flexible wiring board on one side and the flexible wiring board on the other side are connected by connecting the respective conductor patterns and the conductor pads formed on the back surface of the chip carrier and between the exposed conductor pads for connection. The endoscope according to claim 9, wherein the endoscope is attached.