JP2000241718A - Electronic endoscope and endoscopic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the diameter of the tip part of an endoscope small and to prevent a diseased part, etc., from being influenced by excessive irradiation of illuminating light. SOLUTION: By adopting a convex lens 64 as the illumination optical system of the tip part 21 of an insertion part 11, the diameter of the tip part 21 is made small. Then, a surface sequential type CCD 43 having no filter optically separating colors is adopted as an image pickup means, and white light is not supplied to a light guide 63 from a light source device 3 but small surface sequential illuminating light is supplied to energy transmitted through R, G and B filters 75R, 75G and 75B provided in a rotary filter 74. Thus, the intensity of illuminating light at a condensing point 68 in the case of condensing the light at the condensing point 68 through the lens 64 is set to a value at which the diseased part is not influenced, and further the maximum value of illuminating light quantity emitted is restricted by a diaphragm 78 when the emitted light quantity of a lamp 71 is large.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electronic endoscope and an endoscope apparatus which perform color imaging and the like by using an illumination optical system having a positive power.

[0002]

2. Description of the Related Art In recent years, endoscopes provided with an illumination optical system and an observation optical system (objective optical system) at the tip of a slender insertion portion have been widely used in the medical and industrial fields. Recently, an electronic endoscope in which a solid-state imaging device having a function of performing photoelectric conversion is arranged at an image forming position of an objective optical system and an image captured by the solid-state imaging device is displayed on a monitor has been widely used.

[0003] In such an endoscope or electronic endoscope, the outer diameter of the insertion portion limits the possibility of performing an endoscopic examination by inserting the insertion portion. Therefore, it is desirable to make the diameter of the insertion portion as small as possible.

In this case, an endoscope of an optical system needs to have a built-in illumination optical system, an objective optical system, and a tip of an image guide at the tip, and an electronic endoscope has an illumination optical system and an objective optical at the tip. Since it is necessary to incorporate a system, an image sensor, and the like, it is important to reduce the diameter of the distal end of the insertion section.

In order to reduce the diameter of the tip, for example, Japanese Patent Application Laid-Open
JP-A-326318 discloses a convex lens having a positive power as an illumination optical system. Normally, the illumination light emitted from the front end surface of the light guide is expanded and emitted by a concave lens having a negative power. In this case, the diameter of the concave lens is adjusted by the light guide for the function of expanding. If the diameter is not larger than the diameter of the front end, the illumination light emitted from the front end face of the light guide cannot be emitted.

On the other hand, if a convex lens is used, the illumination light emitted from the front end face of the light guide is condensed and emitted. Therefore, in the case of this convex lens, the diameter is almost the same as the diameter of the front end of the light guide. Also, almost all of the illumination light emitted from the end face of the light guide can be emitted. Therefore, the diameter of the distal end can be made smaller when a convex lens is used than when a concave lens is used as the illumination optical system.

[0007]

However, when a convex lens is employed as the illumination optical system, the illumination light is once condensed by the convex lens at the light condensing point because of the function of condensing the light. Especially in the case of the medical field, if the diseased part is set at this focal point and the observation is continued, the large illumination light intensity at the focal point may thermally affect the condition of the diseased part. There is. For this reason, an electronic endoscope or an endoscope apparatus that can more effectively prevent such an influence is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned point, and has an electronic endoscope and an endoscope which can reduce the diameter of a distal end portion and prevent an affected part from being irradiated with excessive illumination light. It is intended to provide a mirror device.

[0009]

A subject illuminated by illumination light emitted from an illumination optical system provided at the distal end of the insertion section is provided with an objective optical system and a solid-state imaging device provided at the distal end of the insertion section. In an electronic endoscope that performs color imaging via a lens, the illumination optical system is formed using a convex lens, and the solid-state imaging device is formed using a solid-state imaging device of a plane-sequential imaging method, so that illumination is performed by a convex lens. Even in the case where a light converging point can be formed, the energy intensity at the converging point can be made smaller than in a case where the light is not plane-sequential light by converting the light into plane-sequential light, so that the tip can be made smaller in diameter and excessive illumination of the affected part, etc. Light irradiation was not applied.

Further, a light source device for generating illumination light, and an illumination light supplied from the light source device are transmitted, emitted through an illumination optical system at a distal end of the insertion portion, and illuminated by the illumination light. An endoscope apparatus including an objective optical system provided at the distal end of the insertion section and an electronic endoscope that performs imaging via a solid-state imaging device, wherein the illumination optical system is formed using a convex lens, and the By providing a limiting means for limiting the amount of energy of illumination light supplied to the electronic endoscope, such as the amount of light or the wavelength, the intensity of energy at the focal point can be reduced even when the focal point can be formed by the convex lens with the illumination light. Then, the diameter of the distal end portion can be reduced, and excessive irradiation of illumination light does not affect the affected part or the like.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 to 5 relate to a first embodiment of the present invention, and FIG. 1 shows a configuration of an electric system of an endoscope apparatus provided with the first embodiment. FIG. 2 shows an appearance of the electronic endoscope according to the first embodiment, FIG. 3 shows a cross-sectional structure of a distal end side of an insertion portion of the electronic endoscope, and FIG.
AA section, BB section, and CC section of FIG. 5 are shown, and FIG. 5 is an operation explanatory view of the field sequential illumination and field sequential imaging. 3A and 3B are cross-sectional views of the insertion portion in FIG. 2, FIG. 3A shows a structure of a channel tube, an imaging unit, and the like, and FIG. 3B shows illumination of a light guide and the like. The structure of the optical system is shown.

As shown in FIG. 1, an endoscope apparatus 1 includes an electronic endoscope 2 according to a first embodiment of the present invention and an electronic endoscope 2 according to the first embodiment.
, A video processor 4 serving as a signal processing device for performing signal processing on image pickup means of the electronic endoscope 2, and a color monitor for displaying a video signal output from the video processor 4. And 5.

As shown in FIG. 2, the electronic endoscope 2 has an elongated insertion portion 11 having flexibility, an operation portion 12 provided at a rear end (base end) of the insertion portion 11, The universal cord 13 extends from the side of the part 12 and a connector 14 provided at the end of the universal cord 13. A light guide connector 15 connected to the light source device 3 is provided at the front end of the connector 14. An electrical connector 16 is provided on a side of the connector 14 to which a signal cable connected to the video processor 4 is connected.

The insertion portion 11 is provided with a front end 21 formed of a hard member, a bendable bending portion 22 provided at the rear end of the front end 21, and a rear end of the bending portion 22. The bending section 22 can be bent by operating a bending operation lever 24 provided on the operation section 12 and having a long flexible section 23 having flexibility.

A treatment instrument insertion port 25 for inserting a treatment instrument such as a biopsy forceps is provided near the front end of the operation section 12. When the treatment instrument is inserted, the channel exits through a channel inside the treatment instrument. , The distal end side of the treatment tool can be protruded, and a biopsy or the like for collecting the diseased tissue can be performed.

As shown in FIG. 3, a resin tip cover 31 is attached near the front end of a hard tip body 30 such as a metal member constituting the tip section 21. The distal end of a cylindrical distal node ring (first cylindrical node or first bending piece) 32a extending toward the curved portion 22 is fixed with a screw 29 as shown in FIG. 4B.

In this case, a hole slightly larger than the outer diameter of the screw (screw) 29 is formed in the tip body 30 so that
A hole smaller than the outer diameter of the screw 29 is formed in 2a, and the screw 29 is screwed in so that a screw hole is formed in the end node ring 32a and fixed.

Here, the diameter of the screw 29 is D1, and the length is L.
1, when the hole diameter D2 and depth of the distal end body 30 are L2, the hole diameter of the distal node ring 32a is D3, and the thickness of the distal node ring 32a is t, the relationship of D1 = D2> D3 is satisfied. In the above, the screw 29 is made detachable in a relationship of L2 + t = L1 + 0.2 to 0.3 (mm). By making the screw 29 detachable in this way, the screw 29 can be removed and the distal end body 30 and the distal node ring 32a can be easily separated at the time of repair such as replacement of a channel.
Repair can be easily performed (in the conventional example, even if the screw 29 is to be removed, it is difficult to idle and remove the screw 29).

A ring-shaped node ring 32b is rotatably connected to a rear end of the node ring 32a by a first rivet 33a.
Are rotatably connected by rivets 33, so that a plurality of node rings are connected to each other so as to be able to bend, and
Are formed.

The outer periphery of the curved portion 22 is covered with an elastic sheath tube 3 such as a mesh tube 34 made of a thin metal wire and a rubber tube.
5 covered. The distal end portion of the outer tube 35 is integrally fixed to the distal end portion main body 30 by a thread winding adhesive portion 36.

The portion closer to the distal end than the first rivet 33a is a portion that rotates integrally with the first node ring 32a, and this portion becomes the distal end (hard distal end) 21. An imaging through hole 38 is provided in the distal end main body 30 in the axial direction at a position below the tip end main body 30, and an imaging unit 39 is attached.

The objective optical system 41 constituting the image pickup unit 39 is composed of a plurality of lenses.
An element fixing frame 44 to which a charge-coupled device (abbreviated as CCD) 43 or the like as a solid-state image pickup device is fitted, is focused, and is fixed to the lens frame 42.

More specifically, a first lens (or lens cover) 41 a constituting the objective optical system 41 is attached to the front end of the lens frame 42, and the front end surface 2 of the front end 21 is
1a, the first lens 41a is formed of, for example, a plano-concave lens.

The distal end of an element fixing frame 44 is fitted and fixed to the outer peripheral surface of the lens frame 42.
At the rear end, an optical filter 45 for cutting infrared rays is adhered and fixed, and at the rear end of the optical filter 45, a CCD 43 protected by a cover glass 46 is arranged.

On the back side of the CCD 43, a circuit board 47 is provided.
A plurality of coaxial lines 48 are connected to the circuit board 47 and the leads of the CCD 43, and a signal cable 49 in which the coaxial lines 48 are put together is inserted into the insertion section 11.
And is connected to the electrical contacts of the electrical connector 16 via the operation unit 12 and the universal cord 13. The electrical connector 16 is connected to the video processor 4 via a connection cable (not shown) to transmit and receive signals to and from the video processor 4.

The optical filter 45 and the cover glass 4
6. The CCD 43, the circuit board 47, and the distal end of the signal cable 49 are covered with an insulating coating 51 such as a heat-shrinkable tube to form a hard portion of the imaging unit 39 that does not deform elastically.

The imaging hole 3 in the tip body 30
Channel mounting through-hole 53 provided adjacent to the upper side of 8
The channel tube 5 forming the channel 54
5 is inserted, and the front end surface thereof is connected to the insulating cover 31.
The channel mounting through hole 53
It is fixed to. The distal end opening of the channel tube 55 communicates with the opening of the distal end cover 31 to form a channel outlet 54a at the distal end surface 21a. In this way, the metal portion is not exposed inside the channel 54.

In this embodiment, in order to reduce the outer diameter of the distal end portion 21, the channel mounting through-hole 53 is formed as shown in FIG.
As shown in (A), a channel mounting through hole 53 and a cutout 56 are formed at the very end of the distal end main body 30, and the outer peripheral surface of the channel tube 55 is formed in the distal end main body 30.
The notch 56 is filled with a water-tight and air-tight soft filler 57 such as a silicone adhesive.

The rear end side of the channel tube 55 communicates with the treatment instrument insertion port 25. Also, the channel through-hole 53 in which the channel tube 55 is provided.
The edge of the tip body 30 on the side of the insulating cover 31 is chamfered, and a space formed by the insulating cover 31 and the chamfered portion is filled with an insulating adhesive to insulate the tip body 30. You may be sure.

Reference numeral 60 in FIG.
2a is one of the ring-shaped wire receivers 60 provided on the inner peripheral surface side, and each of the wire receivers 60
The other end of an operation wire (not shown), one end of which is fixed to the bending operation lever 24, is fixed.

Incidentally, as shown in FIG.
a and a first rivet 33a connecting the second node ring 32b disposed behind the distal node ring 32a is provided at a position distal to the rear end of the hard portion of the imaging unit 39. .

Further, in the horizontal direction passing through substantially the center of the distal end portion 21, the illumination through holes 61 are located on both sides of the imaging through hole 38.
Are provided, and the light guide 6 forming the illumination optical system 62 is provided.
3 is fixed, and a convex lens 64 having a positive power as an illumination lens is fixed opposite to the front end surface. The light guide 63 is covered with a protective tube 65 on the rear side of the illumination through hole 61.

The through hole 61a for the convex lens 64 is slightly larger in diameter than the portion to which the light guide 63 is fixed, and the convex lens 64 is fixed with the convex side of the plano-convex lens inside. Have been.

In this case, in order to reduce the diameter of the distal end portion 21, the through-hole portion 61 a to which the convex lens 64 is attached as shown in FIG. And a notch 65 for processing
The notch 65 is filled with a soft filler 66 to maintain airtightness and watertightness.

Here, the width a of the notch 65 is smaller than the diameter D of the through-hole 61a (that is, D> a as can be seen from FIG. 4C), and positioning when the convex lens 64 is mounted. The length of the part is increased to prevent rattling.

In this embodiment, in order to make the outer diameter of the distal end portion 21 as small as possible, a convex lens 64 is employed as an illumination lens forming the illumination optical system 62.
The diameter is smaller than when a concave lens is used.

In this case, since the convex lens 64 is employed, a light condensing point 68 is provided in front of the convex lens 64 (see FIG. 1).
When the illuminating light from the light source device 3 is directly supplied to the light guide 63, the affected part is focused on the converging point 68.
If the observation is continued with the state of being placed in the electronic endoscope, an excessive illumination light is radiated to the affected part. In order to avoid this, in this embodiment, the electronic endoscope 2 which performs the color image pickup in a frame sequential manner is used. .

That is, in the electronic endoscope 2 of the present embodiment, a plane-sequential type color image pickup means having no mosaic filter or the like for color separation in the optical system is formed on the image pickup surface of the CCD 43.

Correspondingly, a field-sequential illumination light for emitting a field-sequential illumination light for sequentially supplying a plurality of different wavelengths of illumination light to the light source device 3 for supplying the illumination light to the electronic endoscope 2. Forming supply means.

As will be described later, the surface-sequential illumination light uses a filter to restrict the amount of energy for sequentially emitting light in a specific wavelength range by using a filter. The amount will be much smaller.

The effect of light absorption and the like depending on the affected area differs depending on the wavelength. For example, if irradiation with light in one wavelength range of R, G, and B plane-sequential light has the greatest effect, and if white light is applied, Is always affected by the light in that wavelength range, but the field-sequential illumination light irradiates only one-third of one cycle of the light in that wavelength range, so that the effect on the affected part is much smaller.

As described above, by making the illumination light supplied to the electronic endoscope 2 a surface-sequential illumination light, a converging point 68 is formed in front of the convex lens 64, and an object such as an affected part is located at the converging point 68. Even when the observation is made in a certain state, the intensity or energy amount of the illumination light at the light condensing point 68 is made lower than that in the case where the white light is emitted, so that the influence of the excessive illumination light is prevented or prevented. I am trying to reduce it.

Further, in the present embodiment, there may be a light source device in which the light emission intensity of the lamp is large, so that the electronic endoscope 2 can respond to the case of generating such large illumination light. The light source device 3 limits the maximum illumination light amount supplied to the electronic endoscope 2.

The configuration of the endoscope device 1 in this case will be described with reference to FIG. The lamp 71 of the light source device 3 is turned on to generate white light by the lamp power supply from the lamp power supply circuit 72, and is reflected by a parabolic concave mirror to emit white light to the front optical path side. A rotary filter 74 driven by a motor 73 is disposed on the optical path. The rotary filter 74 has, for example, an R filter 75R that transmits R (red), G (green), and B (blue) light, respectively. , G filter 75
G, B filters 75B are attached to the fan-shaped openings, and R, G, B filters 75R, 75G, 75B are sequentially arranged on the optical path by rotation of a motor 73, and R, G, B
, I.e., plane-sequential illumination light. The motor 74 is controlled by a motor control circuit 76 so as to make one rotation at a constant speed, for example, in one frame period of 1/30 second.

The plane-sequential illumination light transmitted through the rotary filter 74 further passes through a stop 78 driven by a stop driver 77 to control the amount of illumination light.
And is supplied to the incident end of the light guide 63.

The illumination light transmitted by the light guide 63 is applied to the light guide 6 attached to the tip 21.
The light is further emitted forward from the distal end surface of the lens 3 via the convex lens 64 to illuminate a subject such as an affected part.

The illuminated subject is formed into an optical image on its focal plane by the objective optical system 41, photoelectrically converted by the CCD 43 disposed on the focal plane, and stored as signal charges. The CCD 43 is connected to the video processor 4 by a signal line or the like.
When a CCD drive signal is applied from the D driver 81, the signal charge that has been photoelectrically converted and accumulated is read out and output as a CCD output signal.

The CCD driver 81 outputs a CCD drive signal after the R, G, and B illumination periods in synchronization with the output signal from the timing controller 82 (see FIG. 5). Further, an output signal of a filter detection sensor (not shown) in the light source device 3 is input to the timing controller 82 to determine the R, G, and B illumination periods.

The output signal of the CCD 43 is amplified by a preamplifier 83 in the video processor 4, and then converted into a digital signal by an A / D converter 84.
, The R, G, and B image signals are stored in R, G, and B memories 86R, 86G, and 86B, respectively, in synchronization with the field sequential illumination.

R, G, B memories 86R, 86G, 86B
Are simultaneously read out, and the D / A
The signals are converted into analog signals by converters 87R, 87G, and 87B to become R, G, and B signals.
After being amplified by 8R, 88G, 88B, the color monitor 5
Are output together with a synchronizing signal (not shown) to the color monitor 5.
The subject image is displayed in color on the display surface of.

The D / A converters 87R, 87G,
The R, G, and B signals output through 87B are input to a dimming signal generation circuit 89, for example, where a dimming signal integrated for one frame period is generated. It is input to the control circuit 91.

The AGC amplifiers 88R, 88G,
The 88B automatically adjusts the gain at the level of the dimming signal. That is, when the level of the dimming signal is low, the gains of the AGC amplifiers 88R, 88G, and 88B simultaneously increase,
If the level of the dimming signal is high, the AGC amplifiers 88R and 88R
The gains of G and 88B decrease at the same time, so that the AGC amplifiers 88R, 88G, 88
After passing through B, the luminance level is set to a substantially constant level.

The dimming control circuit 91 is supplied with a reference voltage Er from a reference level generating circuit 92 for generating a reference level for brightness suitable for observation.
The aperture signal is output to the aperture driver 77, and the opening and closing (rotation) of the aperture 78 is controlled so as to reduce the deviation from the reference voltage Er.

In this embodiment, for example, the connector 14 of the electronic endoscope 2 is provided with a resistor 93 for identifying a resistance value corresponding to the type of the electronic endoscope 2.
Is connected to the light source device 3, the resistance value of the identification resistor 93 is input to the aperture driver 77 via the contact. An output signal of a sensor (not shown) such as a potentiometer for detecting the aperture position of the aperture 78 is input to the aperture driver 77.

In contrast to the case of the electronic endoscope 2 using the convex lens 64 as an illumination lens, the lamp 71 of the light source device 3
When illumination light is supplied in a plane-sequential manner with a light emission amount of
The aperture driver 78 limits the maximum aperture of the aperture 78 so that the illumination light intensity at 8 does not affect the affected part.

On the other hand, in the case of an electronic endoscope in which a concave lens (not shown) is used as an illumination lens, no converging point is formed. Therefore, when this electronic endoscope is connected, the resistance value of the connector is as described above. Since the resistance value of the identification resistor 93 is different from the resistance value, the maximum aperture of the diaphragm 78 is not limited.

In this embodiment, the convex lens 64 is employed as the illumination optical system 62 provided at the distal end portion 21, thereby reducing the diameter of the distal end portion 21. The illumination light supplied from the light source device 3 to the electronic endoscope 2 is converted into color light transmitted through the R, G, and B filters 75R, 75G, and 75B so that the illumination light does not affect the affected part or the like. The intensity or energy amount is limited to an allowable value.

Further, since the amount of illumination light generated by the lamp 71 may be large depending on the light source device 3, a signal (specifically, a resistance value) indicating the type when the electronic endoscope 2 is connected is provided. The maximum opening amount of the stop 78 in the light source device 3 is limited so that the illumination light intensity or the energy amount is allowed even when the observation is performed with the affected part set at the focal point 68.

According to the present embodiment, the diameter of the distal end portion 21 can be reduced, so that the distal end portion 21 can be easily inserted into a narrower body cavity, and the pain given to the patient during the insertion can be reduced. .

When an endoscope inspection is performed using this embodiment, the illumination light intensity at the focal point 68 is supplied to the electronic endoscope 2 from the light source device 3 side so as to be less than an allowable value. The illumination light to be used is set to be a frame-sequential illumination light, and when the supplied illumination light is large, the amount of the illumination is limited, so that the level of the dimming signal is reduced particularly when a distant part is observed. The dimming loop may have an AG
Since the C amplifiers 88R, 88G and 88B are provided, the signals are amplified to a normal level by the AGC amplifiers 88R, 88G and 88B, so that an image having a brightness suitable for observation can be obtained.

That is, even if the luminance levels of the R, G, and B signals output through the D / A converter 87R and the like are lowered, the luminance levels are amplified to normal levels by the AGC amplifiers 88R, 88G, and 88B, so that the observation is easy. A bright image is obtained. In this case, although the S / N ratio is reduced, since the image is for a distant place, a request for sharpness is often not so required. On the short distance side, usually, automatic dimming can be performed in a state where the aperture 78 is narrowed, and the S / N is the same as in the normal case where the illumination light amount is not limited.
And a good image can be obtained.

The operation of the frame sequential illumination and the frame sequential color imaging under the frame sequential illumination according to the present embodiment will be described with reference to FIG. The white light of the lamp 71 of the light source device 3 passes through a rotary filter 74 that is driven to rotate by a motor 73, so that the R, G, and B plane-sequential illuminating light is applied to the electronic endoscope 2 as shown in FIG. Is supplied to the light guide 63.

At the end of the R, G, and B plane sequential illumination light,
As shown in FIG.
The drive signal is applied to the CCD 43, the signal charges stored in the CCD 43 are read out, amplified by the preamplifier 83, converted to digital signals by the A / D converter 84, and then selected by the selector 85 for R, G, B memory 86
R, 86G and 86B.

That is, as shown in FIG. 5C, the signal of the R component which is picked up under the R illumination and output from the CCD 43 is stored in the R memory 86R, and as shown in FIG. The signal of the G component which is imaged under and output from the CCD 43 is stored in the G memory 86G, and the signal of the B component which is imaged under B illumination and output from the CCD 43 as shown in FIG. It is stored in the B memory 86B.

These R, G, B memories 86R, 86
The R, G, B signal components stored in the G, 86B are simultaneously read out, input to the color monitor 5 via the D / A converter 87R, etc. and the AGC amplifier 88R, etc., and the subject image is displayed on the display surface of the color monitor 5. Is displayed in color.

The analog R, G, B signals that have passed through the D / A converter 87R and the like are input to a dimming signal generation circuit 89, converted into a luminance signal, and further integrated for one frame period to perform dimming. A signal is generated and input to the dimming control circuit 91 of the light source device 3.

Then, it is compared with the reference voltage Er, and based on the error signal, the opening / closing of the aperture 78 is controlled via the aperture driver 77, and the light is automatically adjusted so that the level of the dimming signal matches the reference voltage Er. At the same time, in the present embodiment, the maximum aperture of the stop 78 is limited so that the illumination light intensity at the focal point 68 does not exceed an allowable value (when the light emission amount of the lamp 71 is small, the stop 78 Even if the aperture is maximized (if the amount of light of this limited maximum aperture in the case of a large lamp is not reached), it is not limited).

Therefore, when observing with the aperture 78 considerably narrowed except when observing a distant place, the level of the dimming signal is made to match the reference voltage Er as in the normal case. It is possible to observe the subject image in a state where the light is automatically adjusted.

On the other hand, when the diaphragm 78 is observed in a state close to its maximum aperture state, such as when observing a distant place, the maximum aperture of the diaphragm 78 is more restricted than in automatic light control. Even if the priority is given, even if the level of the dimming signal is lower than the reference voltage Er, the diaphragm 78 does not open beyond the limited maximum aperture due to the limitation of the maximum aperture.

For this reason, according to the present embodiment, even when the light emission amount of the lamp 71 is large, the maximum aperture of the stop 78 is limited. In addition, it is possible to reliably prevent excessive illumination light irradiation on the affected part and observe the diseased part.

When the amount of illumination light emitted by the lamp 71 is large, the maximum illumination light amount is limited by the stop 78. However, when the illumination light amount of the lamp 71 is not large, the stop 78 is limited. It is not necessary to limit the amount of illumination. According to the present embodiment, the diameter of the distal end portion 21 can be reduced, and it is also possible to prevent the diseased part or the like from being observed in a state where excessive illumination light is irradiated.

Further, when the convex lens 64 is employed, the processing accuracy of the convex lens 64 can be higher than when the concave lens is employed as the illumination optical system, and there is less variation even when a smaller illumination optical system is formed. The electronic endoscope 2 with high quality can be provided, and the endoscope apparatus 1 that can obtain an endoscope image with little illumination unevenness can be realized.

(Second Embodiment) Next, a second embodiment of the present invention will be described below with reference to FIG. FIG. 6 shows a configuration of an endoscope apparatus 101 provided with a second embodiment of the present invention. This embodiment is different from the first embodiment in that
A simultaneous electronic endoscope 102 is employed in place of the frame sequential electronic endoscope 2.

The endoscope apparatus 101 comprises a simultaneous electronic endoscope 102 according to the second embodiment and the electronic endoscope 102.
, A video processor 104 as a signal processing device for performing signal processing on image pickup means of the electronic endoscope 102, and a color monitor for displaying a video signal output from the video processor 104 105.

The simultaneous electronic endoscope 102 is different from the first embodiment in that, for example, a mosaic filter 106 as a color separation filter is provided in front of the image pickup surface of the CCD 43. The configuration is the same as that of the first embodiment.

The light source device 103 is the light source device 3 shown in FIG.
In this configuration, the motor 73, the rotary filter 74 and the motor control circuit 76 are removed, and the white light of the lamp 71 is supplied to the entrance end of the light guide 63 via the stop 78 and the condenser lens 79.

Also, the video processor 104 applies a CCD drive signal from the CCD driver 111 to the CCD 43 and reads out signal charges that have been photoelectrically converted and stored, as in the video processor 4 of FIG.

The CCD driver 111 outputs a CCD drive signal in a cycle of one frame period in synchronization with an output signal from the timing controller 112.

The CCD output signal is amplified by a preamplifier 113 and converted into a digital signal by an A / D converter 114, and then input to a color separation circuit 115 to receive color difference signals RY and BY as color signals and a luminance signal. Y is generated and stored in the RY memory 116a, the BY memory 116b, and the Y memory 116c, respectively.

RY memory 116a, BY memory 11
6b and the signals stored in the Y memory 116c are read out at the same time, and the D / A converters 117a and 117 are respectively read.
b and 117c, are converted into analog signals, input to the matrix circuit 118, converted into R, G, B signals,
After being amplified by the AGC amplifiers 119a, 119b, and 119c, the amplified image is output to the color monitor 105, and the subject image is displayed in color on the display surface of the color monitor 105.

The luminance signal Y output from the color separation circuit 115 is input to the dimming signal generation circuit 120, and a dimming signal integrated for one frame period is generated. It is input to 91. Further, similarly to the first embodiment, the AGC amplifier 119 uses the dimming signal.
a, 119b and 119c are controlled.

The dimming control circuit 91 is supplied with a reference voltage Er from a reference level generating circuit 92 for generating a reference level for brightness suitable for observation.
The aperture signal is output to the aperture driver 77, and the opening and closing (rotation) of the aperture 78 is controlled so as to reduce the deviation from the reference voltage Er.

In the present embodiment, for example, the connector 14 of the electronic endoscope 2 is provided with a resistor 93 for identifying a resistance value corresponding to the type of the electronic endoscope 2.
Is connected to the light source device 103, the resistance value of the identification resistor 93 is input to the aperture driver 77 via the contact. An output signal of a sensor (not shown) such as a potentiometer for detecting the aperture position of the aperture 78 is input to the aperture driver 77.

In the case of the electronic endoscope 102 in which the convex lens 64 is used as an illumination lens, the light source device 3 stops the illumination light at the focal point 68 so that the intensity of the illumination light does not affect the affected part. The driver 78 limits the maximum aperture of the stop 78.

On the other hand, in the case of an electronic endoscope in which a concave lens is used as an illumination lens, no focal point is formed. Therefore, when this electronic endoscope is connected, the resistance value of the connector is equal to the identification value. Since the resistance value is different from the resistance value of the resistor 93,
The maximum aperture of the stop 78 is not restricted.

In this embodiment, the convex lens 64 is employed as the illumination optical system 62 provided at the distal end portion 21, thereby reducing the diameter of the distal end portion 21. Limits the maximum amount of illumination light supplied from the light source device 103 to the electronic endoscope 102 to a value less than or equal to a value permitted by the diaphragm 78 so that the light does not affect the affected part.

In this embodiment, when a freeze switch (not shown) is operated, the RY memory 116
a, Writing of signals to the BY memory 116b and Y memory 116c is prohibited, the signal written immediately before is repeatedly output, and a still image is displayed on the color monitor 105.

When the function of displaying a still image is not required, the RY memory 116a, the BY memory 116b,
The memory 116c is unnecessary (in this case, the A / D converter 114, the D / A converters 117a and 117b,
117c becomes unnecessary).

According to the present embodiment, since the diameter of the distal end portion 21 can be reduced, the distal end portion 21 can be easily inserted into a narrower body cavity, and the pain given to the patient during the insertion can be reduced. .

When an endoscopic examination is performed using this embodiment, the amount of illumination is limited so that the intensity of the illumination light at the focal point 68 is equal to or less than an allowable value. When the site is observed, the level of the dimming signal may be reduced. However, since the AGC amplifiers 119r, 119g, and 119b are provided at the subsequent stage of the dimming loop, the AGC amplifiers 119r and 119g are provided. , 119b, the image is amplified to a normal level, so that an image having a brightness suitable for observation (although the S / N is degraded) is obtained.

On the short distance side, an image similar to that in a normal case where the amount of illumination light is not limited can be obtained.

Since the second embodiment outputs white light in comparison with the first embodiment, the function of limiting the amount of illumination light by the stop 78 is the same as that of the lamp 71 having the same light emission amount. For example, it is three times or more larger than that of the first embodiment.

In other words, in the first embodiment, except that the illumination light amount supplied from the light source device 3 is large,
In many cases, it is substantially unnecessary to limit the amount of illumination light on the light source device 3 side.

(Third Embodiment) Next, a third embodiment of the present invention will be described below with reference to FIGS.
FIG. 7 shows an endoscope apparatus 1 having a third embodiment of the present invention.
FIG. 8 shows an operation explanatory diagram thereof. This embodiment is different from the second embodiment in that an imaging period shorter than a normal imaging period, that is, an image is captured by an element shutter.

In this case, it seems that a method of performing continuous illumination without forming a light-blocking period on the illumination side in a normal element shutter seems to be adopted. In this embodiment, except for the imaging period in which imaging is performed by the element shutter, I try to shield the light.

For this reason, the endoscope apparatus 101 'shown in FIG.
In the endoscope device 101 shown in FIG. 6, a liquid crystal element shutter 121 is disposed on the optical path of the light source device 103, and the transmission / non-transmission of the illumination light amount of the liquid crystal element shutter 121 is controlled by a shutter driver 122. The shutter driver 122 is connected to the timing controller 112 in the video processor 112, and is set to transmit illumination light only during an imaging period T (see FIG. 8) in which imaging is performed by the element shutter.

That is, as shown in FIG. 8A, the liquid crystal element shutter 121 periodically opens only during a short imaging period T in one frame period (more specifically, is set to a transmission state). Later, as shown in FIG.
The CD driver 111 applies a transfer signal (also referred to as a readout pulse) to the CCD 43 to transfer the signal charges accumulated in the photosensitive section (imaging section) to the vertical transfer section, and then, as shown in FIG. The CCD 43 outputs a signal charge transferred to the vertical transfer unit by applying a CCD drive signal (such as a horizontal transfer signal). Other configurations are the same as those of the second embodiment.

In the present embodiment, by limiting the amount of illumination light supplied to the electronic endoscope 102 per unit time, the illumination light intensity allowed even when the affected part is set at the focal point 68 Is set to

Specifically, as can be seen from the operation explanatory diagram of FIG. 8, the light source device 103 supplies the illumination light to the light guide 63 side of the electronic endoscope 102 only during the short imaging period T in one frame period. Even in a state where the affected part is set at the focal point 68, the illumination light intensity per unit time can be sufficiently reduced, and an endoscopic examination can be performed with little effect on the affected part and the like. In addition, since the illumination light is shielded so as to be linked with the imaging period T, it is not necessary to sweep out unnecessary charges that are not required when the light is not shielded.

In this embodiment, the maximum light amount supplied by the stop 78 is limited, but the maximum light amount is much larger than that of the second embodiment (for example, for one frame period). , The imaging period T is reduced to a fraction
The maximum light amount to be limited can be set to several times or several tens times by setting to 1 to several tenths. If the imaging period T is shortened, it is not necessary to limit by the stop 78. .

Further, the imaging period can be variably set, and the variably set value changes the time average value of the allowable illumination light intensity or energy amount at the light condensing point 68. The maximum value of the illumination light amount when supplied from the light source device side may be variably set.

In the present embodiment, imaging is performed in a short imaging period T, so that a clear image with little blur can be obtained even when observing a rapidly moving part. The other effects are the same as those of the second embodiment.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described below with reference to FIG. FIG. 9 shows a convex lens 131 constituting an illumination optical system in an electronic endoscope according to a fourth embodiment of the present invention.

In the present embodiment, the convex lens 131 is set so as to have a partially different focal length. For example, the convex lens 131 is set so that the radii R1 and R2 are different so that the focal length of the central portion is different from the focal length of the peripheral portion.

As described above, by setting not to collect light at a single focal length but to collect light at a plurality of focal lengths, the energy density at the most focused portion can be reduced, and the allowable maximum Illumination light can be increased.

Note that the focal length may be set so as to be continuously distributed.

FIG. 10 shows a convex lens 141 in a modified example. FIG. 10A shows, for example, a cross-sectional shape of the two convex lenses 141 in a cross-section passing through the center of the two convex lenses 141 in the distal end portion main body, and FIG.
(A) shows a cross section passing through the center of one convex lens 141 in a direction perpendicular to the direction.

In this case, assuming that the focal length of the convex lens in the horizontal direction is Fh, the convex lens 14 in the vertical section
One focal length Fv is shorter than the horizontal focal length Fh. That is, in an extreme case, it has a lens function similar to a cylindrical lens.

As in the case of FIG. 9 of this modification, the number of light condensing points can be dispersed to a plurality of points instead of one point, so that the maximum value of the allowable amount of illumination light can be increased.

In this modification, the observation window of the imaging unit is set near the center of the two convex lenses 141 in FIG. 10A, and in this case, the illumination is performed by the convex lenses 141 on both sides of the imaging window. Since two light sources are not arranged in the vertical direction, the focal length in the case of emitting light in the vertical direction is shorter than that in the case of the horizontal direction, so that uneven illumination can be reduced.

In each of the above-described embodiments, when an operator observes a subject such as an affected part, and it is certain that the observer observes the subject without setting it at the focal point 68, the illustration is omitted. The operation of the foot switch etc.
For example, limiting the maximum illumination light supplied to the electronic endoscope 2 or 102 in the light source device 3 or 103 or the like for a fixed time may be stopped.

In each of the above embodiments, the electronic endoscope 2
The illumination light is supplied to the electronic endoscope 2 and the like from the external light source device 3 and the like, but the distal end portion 2 of the electronic endoscope 2 has been described.
The present invention can also be applied to a case where a light source such as a light emitting diode is built in the device 1.

In this case, the amount of illumination light supplied from the lamp of the external light source device is often smaller than the amount of illumination light, and even if the diseased part is set at the focal point 68 and observed, the diseased part is not affected. You may be able to do so.

That is, when the illumination optical system is formed by employing a light emitting device such as a light emitting diode at the distal end of the insertion portion, it may not be necessary to limit the amount of light emitted by the light emitting diode even if a convex lens is employed. Many.

In the above description, color imaging is performed. However, when color imaging is not performed and observation is performed by irradiating light of a specific wavelength, for example, the light source device side moves to the electronic endoscope side. In some cases, the maximum value of the illuminating light that can be supplied can be relaxed or need not be limited. In addition, embodiments and the like configured by combining the above-described embodiments and the like in part or the like also belong to the present invention.

[Supplementary Notes] An electronic endoscope that performs color imaging of a subject illuminated under illumination light emitted from an illumination optical system provided at the distal end of the insertion section through an objective optical system provided at the distal end of the insertion section and a solid-state imaging device. An electronic endoscope, wherein the illumination optical system is formed using a convex lens, and the solid-state imaging device is formed using a plane-sequential imaging type solid-state imaging device.

[0118] 2. A light source device for generating illumination light, transmitting the illumination light supplied from the light source device, emitting the illumination light through the illumination optical system at the distal end of the insertion portion, and moving the subject illuminated with the illumination light to the distal end of the insertion portion. In an endoscope apparatus including an objective optical system provided in the unit and an electronic endoscope that performs imaging through a solid-state imaging device, the illumination optical system is formed using a convex lens,
And an endoscope apparatus provided with a limiting means for limiting an amount of energy of illumination light supplied to the electronic endoscope.

3. 3. The endoscope apparatus according to claim 2, wherein the limiting unit limits the amount or wavelength of illumination light supplied from the light source device to the electronic endoscope. 4. Supplementary note 2 wherein the limiting means periodically limits the illumination light supplied from the light source device to the electronic endoscope.
The endoscope apparatus according to claim 1. 5. The means for limiting the amount of illumination light supplied from the light source device to the electronic endoscope is a diaphragm.
The endoscope apparatus according to claim 1.

6. The means for limiting the wavelength of the illumination light supplied from the light source device to the electronic endoscope is obtained by attaching a color transmission filter that transmits light in a plurality of wavelength ranges to a rotary filter rotated by a motor. 4. The endoscope apparatus according to claim 3, wherein 7. 3. The endoscope apparatus according to claim 2, wherein the limiting means limits the illumination light intensity or the energy density at the converging point by the convex lens to an allowable value or less. 8. The light source device has an identification unit for identifying the electronic endoscope using the convex lens, and the limiting unit limits the illumination light supplied to the electronic endoscope corresponding to the identified electronic endoscope. 3. The endoscope device according to 2.

9. An additional dimming unit that automatically adjusts the amount of illumination light supplied from the light source device to the electronic endoscope based on an output signal from the solid-state imaging device so as to maintain a reference value. 3. The endoscope device according to 2. 10. In the case where the automatic light control is performed by the automatic light control unit, and when the light amount of the illumination light supplied from the light source device to the electronic endoscope is reduced to a light amount that cannot be maintained at a reference value, the display unit is used. Characterized in that a means for increasing the gain of the video signal output to the side is provided.
The endoscope apparatus according to claim 1. 11. 3. The endoscope apparatus according to claim 2, wherein the convex lens has a property of condensing light at a plurality of focal lengths.

[0122]

As described above, according to the present invention, the object illuminated by the illumination light emitted from the illumination optical system provided at the distal end of the insertion section is provided at the distal end of the insertion section. In an electronic endoscope that performs color imaging through an optical system and a solid-state imaging device, the illumination optical system is formed using a convex lens, and the solid-state imaging device is formed using a solid-state imaging device of a plane-sequential imaging method. Therefore, even when a converging point can be formed with illumination light by the convex lens, the energy intensity at the converging point can be made smaller than in the case where the light is converted into plane-sequential light and non-plane-sequential light, and the tip can be made smaller in diameter. In addition, it is possible to prevent an excessive illumination light from irradiating the affected part or the like.

Further, a light source device for generating illumination light, and the illumination light supplied from the light source device are transmitted, emitted through an illumination optical system at the distal end of the insertion portion, and illuminated by the illumination light. An endoscope apparatus including an objective optical system provided at the distal end of the insertion section and an electronic endoscope that performs imaging via a solid-state imaging device, wherein the illumination optical system is formed using a convex lens, and the Since the limiting means for limiting the amount of energy of the illumination light supplied to the electronic endoscope is provided, even when a focal point can be formed by the convex lens with the illumination light, the energy intensity at the focal point is reduced, and The diameter of the part can be reduced, and the affected part or the like can be prevented from being irradiated with excessive illumination light.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electric system of an endoscope apparatus provided with a first embodiment of the present invention.

FIG. 2 is an exemplary perspective view showing the appearance of the electronic endoscope according to the first embodiment;

FIG. 3 is a diagram showing a cross-sectional structure of a distal end side of an insertion portion of the electronic endoscope.

FIG. 4 is a sectional view taken along line AA, BB, and CC of FIG. 3;

FIG. 5 is an operation explanatory diagram of a frame sequential illumination and a frame sequential imaging.

FIG. 6 is a configuration diagram of an electric system of an endoscope apparatus according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of an electrical system of an endoscope apparatus according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of the operation.

FIG. 9 is a diagram showing a shape of a convex lens according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a focal length of a convex lens in a modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Endoscope apparatus 2 ... Electronic endoscope 3 ... Light source device 4 ... Video processor 5 ... Color monitor 11 ... Insertion part 21 ... Tip part 30 ... Tip part main body 31 ... Tip cover 32a ... Tip node ring 35 ... Outer tube Reference numeral 38 denotes a through hole for imaging 39 ... an imaging unit 41 ... objective optical system 43 ... CCD 49 ... signal cable 53 ... through hole for channel 54 ... channel 61 ... through hole for illumination 62 ... illumination optical system 63 ... light guide 64 ... convex lens 65 ... Notch 66 ... Filler 71 ... Lamp 74 ... Rotary filter 75R, 75G, 75B ... Filter 78 ... Aperture 91 ... Light control circuit 93 ... Identification resistor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H040 BA11 CA04 CA10 CA12 DA12 DA17 GA02 GA05 4C061 AA00 AA29 BB02 CC06 DD03 FF40 FF46 FF47 LL02 MM03 NN01 QQ09 RR02 RR04 RR12 RR14 RR15

Claims (3)

[Claims] A color image of a subject illuminated under illumination light emitted from an illumination optical system provided at a distal end portion of an insertion portion via an objective optical system provided at a distal end portion of the insertion portion and a solid-state imaging device. An electronic endoscope, wherein the illumination optical system is formed using a convex lens, and the solid-state imaging device is formed using a solid-state imaging device of a plane sequential imaging method. 2. A light source device for generating illumination light, and an illumination light supplied from the light source device is transmitted, emitted through an illumination optical system at a distal end portion of an insertion portion, and illuminated by the illumination light. An endoscope apparatus including an objective optical system provided at the distal end of the insertion section and an electronic endoscope that performs imaging via a solid-state imaging device, wherein the illumination optical system is formed using a convex lens, and An endoscope apparatus provided with a limiting means for limiting an energy amount of illumination light supplied to an electronic endoscope. 3. The endoscope apparatus according to claim 2, wherein said limiting means limits the amount or wavelength of illumination light supplied from said light source apparatus to an electronic endoscope.