JP3235832B2 - Endoscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus, and more particularly, to an endoscope apparatus which takes measures against burns caused by illumination light applied to a subject.

[0002]

2. Description of the Related Art In recent years, by inserting an elongated insertion portion into a body cavity, it is possible to observe an organ in the body cavity, and if necessary,
2. Description of the Related Art An endoscope capable of performing various medical treatments using a treatment tool inserted into a treatment tool channel is widely used.

[0003] Boilers, gas turbine engines,
2. Description of the Related Art Industrial endoscopes are widely used for observing and inspecting internal scratches and corrosion of pipes of chemical plants and the like and automobile engines and the like.

Further, various types of electronic endoscopes using a solid-state imaging device such as a charge-coupled device (CCD) as an imaging means have been used.

[0005] The electronic endoscope apparatus has the following advantages over conventional optical fiber endoscopes, which use optical fibers as image transmission means, because there is no deterioration in image quality due to fiber breakage, and image recording is easy. It is in a situation where it is widely used as the performance of solid-state imaging devices is improved.

Some electronic endoscope apparatuses using an electronic endoscope are provided with a photometric unit and an exposure amount control unit in order to optimally control the brightness of an observed image. That is, this apparatus controls the exposure amount of the image sensor so that the brightness of the image detected by the photometric means is always constant.

In addition to the adjustment of the exposure amount, there has been proposed an apparatus provided with an automatic dimming circuit for automatically controlling the amount of light incident on the image pickup means to an appropriate level. This device keeps the amount of light incident on the image pickup means properly, and prevents the image quality of the obtained image from deteriorating. For example, there is a technique described in Japanese Patent Application Laid-Open No. Sho 62-140564 and Japanese Patent Application Laid-Open No. Hei 3-118022 in which the response is improved by improving the technology. In these techniques, a dimming signal is generated by using an output of a solid-state imaging device that is an imaging unit, an opening / closing amount of a light source side aperture is controlled, and an illumination light amount emitted from a light source of the light source device is appropriately controlled. As a result, the amount of light incident on the imaging means is maintained at an appropriate level.

On the other hand, in an endoscope apparatus using an electronic endoscope or a fiber type endoscope, a technique for preventing a large amount of illumination light from irradiating an observation site and preventing the observation site from being damaged due to the heat. Has been proposed. This technology is disclosed in
This is a device having a special configuration proposed in JP-A-212219. That is, of the illumination light emitted from the endoscope distal end portion, the position of the endoscope distal end portion can be confirmed by so-called transillumination, which is an increase in light transmitted outside the body, and when the extracorporeal observation mode is selected. The mode is canceled by a time setting means after a predetermined time has elapsed. As described above, the increase in light due to the transillumination is automatically canceled, so that the occurrence of burns due to observation light can be prevented.

[0009]

In a conventional electronic endoscope apparatus, the automatic light control for controlling the illumination light amount of the light source is controlled by the total light amount received by the solid-state imaging device. However, if the irradiation light amount is excessively increased to obtain a sufficient imaging light amount, there is a possibility that the living tissue may be thermally denatured (burned) by the light energy of the irradiation light even though it is not as high as transillumination.

In an endoscope with an automatic iris for automatically controlling the iris on the image pickup means side, controlling the auto iris in association with the aperture of the light source requires a large circuit scale and is technically difficult. It was a priority control. That is, conventionally, control is performed by changing the detection time constant of the auto iris and the light source aperture, and the time constant of the imaging side iris is reduced to prioritize. Therefore, the light source is often used in the vicinity of the maximum light quantity, and it is necessary to take measures against burns in the body.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an endoscope apparatus which controls a living tissue as a subject so as not to be burned by heat of illumination light.

[0012]

An endoscope apparatus according to the present invention comprises: a light source for emitting illumination light for illuminating a subject; an objective optical system for forming an image of the subject on the subject; A solid-state imaging device that captures the subject image to be imaged; a light amount detection circuit that detects a luminance component from an output signal of the solid-state imaging device; and an exposure of the solid-state imaging device based on the luminance component detected by the light amount detection circuit. Solid-state imaging device for sending a drive signal for controlling a period to the solid-state imaging device
And a drive signal for controlling the exposure period of the image sensor controlled by the solid-state image sensor drive circuit.
Light source emission period control means for blinking the light source means in synchronization with a signal, and
The aperture amount is determined based on the luminance component detected by the mass detection circuit.
An imaging-side throttle means controlled, prior to the imaging-side throttle means
Depending on the opening amount, the illumination light emitted by the light source means
And a dimming control circuit for controlling the intensity .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an endoscope apparatus to which the present invention is applied.

As shown in FIG. 1, an endoscope apparatus 1 has an endoscope 3 in which a solid-state image pickup device 2 as an image pickup means is arranged at the distal end of an insertion portion, and processes an output of the solid-state image pickup device 2 to a standard. (Camera control unit) 4 that converts the output into a typical video signal and outputs the same, a monitor 5 that receives the output of the CCU 4 and displays an endoscope image, and a light source device 6 that supplies illumination light to the endoscope 3 And

The endoscope 3 is located at the distal end of the insertion portion, and is provided with an objective optical system 8 for forming an image of a subject 7 on the solid-state image pickup device 2 and a light source device 6 for irradiating the subject 7. Through which a light guide 9 for transmitting illumination light from the light source is inserted.

The light source device 6 has a light source lamp 10 for emitting illumination light, and a stop 11 provided between the incident end of the light guide 9 and the light source lamp 10. This aperture 11
The amount of illumination light incident on the light guide 9 is adjusted.

The solid-state imaging device 2 is driven by the CCU 4 and supplies an electric signal obtained by photoelectrically converting the subject image to the CCU 4 via the signal line 12. The above is the overall configuration diagram of the endoscope apparatus to which the present invention is applied.

FIGS. 2 and 3 relate to the first embodiment of the present invention. FIG. 2 is a structural view of a main part of the endoscope apparatus, and FIG. 3 is a timing chart showing the operation of the endoscope apparatus of FIG. It is.

The endoscope device 95 shown in FIG. 2 is configured to optimally control the amount of irradiation light so that the living tissue is not burned. The endoscope device 95 includes an endoscope 96,
It has a CCU 97 and a light source device 98. Endoscope 9
Reference numeral 6 denotes a CCD 99 as a solid-state imaging device, and the CCD 99
And an iris 100 arranged in front of the iris 99.
The output of the CCD 99 is converted to a standard video signal by a signal processing circuit 102 that performs various signal processing via a preamplifier of the CCU 97, and is output to the outside. Among the processing signals of the signal processing circuit 102, for example, a CDS (not shown)
The output of the (double integration sampling circuit) is such that a luminance component is detected by the light amount detection circuit 103 and is output to the iris driver 104 and the CCD driver 105 as a control signal.

The iris driver 104 appropriately controls the amount of opening and closing of the iris 100 according to the control signal.

On the other hand, the CCD driver 105 controls the CCD 99 so as to read out the accumulated charges during the transfer period, and sends a signal synchronized with the timing of the exposure period in which the CCD 99 accumulates the charges to the pulse width control circuit 127 of the light source device 98. Output. The pulse width control circuit 127 controls the light source 128 in synchronization with the exposure period.

In the above configuration, the amount of illumination light is detected from the output of the CCD 99, the iris 100 is controlled by the iris driver 104, and the iris 100 is adjusted together with the CCD element shutter.
Performs optimal control of the detected light amount. At this time, in accordance with the exposure period of the CCD element shutter shown in FIG.
As shown in (a), the light source 128 of the light source device 98 is pulse-lit. At this time, the trigger TRIG and the timing signal SG shown in FIGS. 3C and 3D are output from the CCD driver 105 to the pulse width control circuit 127, and the light source 128 emits light in synchronization with the trigger TRIG. The light turns off in synchronization with the timing signal SG. Then, the light source 128 is turned on only during the exposure time of the electronic shutter of the CCD.

In the present embodiment, by turning on the light source only during the period in which the CCD element shutter is exposed, the total amount of light applied to the living tissue can be reduced, and the living tissue can be prevented from being burned. .

FIGS. 4 and 5 relate to a second embodiment of the present invention. FIG. 4 is a block diagram of the endoscope apparatus, and FIG. 5 is a timing chart showing the operation of the endoscope apparatus.

The endoscope device 121 of the present embodiment is different from the first embodiment in that the iris 100 on the CCD 99 side is provided.
There is also a configuration in which the light emission pulse width of the light source is changed with respect to the opening amount. For this reason, the CCU 97 of the first embodiment
And CCU 122 and light source device 1 in place of light source device 98
23. In addition, the same configurations and operations as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different points will be described.

The CCU 122 includes the light amount detection circuit 1
03 through the dimming control circuit 124 to the CCD
A driver 105 and the iris driver 104 are supplied.

The iris driver 104 controls the aperture of the iris 100 and the aperture of the light source side stop 126 by the iris control circuit 125 of the light source device 123 in accordance with the output of the dimming control circuit 124. . Also,
The CCD driver 105 controls the speed of the element shutter of the CCD 99, that is, the exposure time, and supplies a control signal to the pulse width control circuit 127 of the light source device 123. The pulse width control circuit 127 causes the light source 128 to emit a pulse light by the control signal, and controls the light emission period.

In the above configuration, when the iris 100 is driven in the closing direction as shown in FIG. 5D under the control of the iris driver 104, the amount of light incident on the CCD 99 decreases. For this reason, under the control of the dimming control circuit 124, the iris control circuit 125 drives the light source side aperture 126 in the opening direction, and the illumination pulse intensity increases as shown in FIG. Conversely, when the iris 100 is driven in the opening direction, the illumination pulse intensity becomes weak. That is, the present device 121
Controls the intensity of the light emission pulse in accordance with the opening amount of the iris on the CCD side so as to maintain the brightness of the CCD image properly.

The dimming control circuit 124 varies the shutter speed of the CCD 99 in accordance with the brightness of the CCD image, and attempts to capture an image with proper exposure. At this time, CCD
When the shutter speed of the shutter 99 increases as shown in FIG. 5A, the timing at which the timing signal SG shown in FIG. 5C is generated with respect to the trigger TRIG shown in FIG. The light emission period also becomes shorter. That is, the present apparatus 121 controls the emission period of the illumination light to be synchronized with the exposure period of the CCD 99.

The dimming control circuit 124 performs the control based on the output of the light amount detection circuit 103. That is, illumination light is emitted during the shutter speed, the iris aperture, the light emission period of the illumination pulse, and the like. Control is performed according to the brightness of the subject (imaging target).

In the present embodiment, by turning on the light source only during the period in which the CCD element shutter is exposed, the total amount of light irradiated to the living tissue can be reduced, and the living tissue can be prevented from being burned. . In the present embodiment, the exposure period of the CCD element shutter is changed according to the brightness of the imaging target, and good image quality can be maintained even when the target changes.

FIGS. 6 and 7 relate to a third embodiment of the present invention. FIG. 6 is a block diagram of the endoscope apparatus, and FIG. 7 is a waveform diagram for explaining the operation of the endoscope apparatus.

The endoscope device 131 of this embodiment is a CCD
The light emitting pulse waveform of the light source is changed with respect to the opening amount of the iris 100 on the 99 side. For this reason,
A CCU 132 and a light source device 133 are provided instead of the CCU 122 and the light source device 123 of the second embodiment. In addition, the same components and operations as those in the second embodiment are denoted by the same reference numerals, description thereof will be omitted, and only different points will be described.

The CCU 132 shown in FIG. 6 has a dimming control circuit 134 for controlling the light source device 133, instead of the dimming control circuit 124. Further, the light source device 133 includes
A pulse width control circuit 135 and a pulse intensity control circuit 136 are provided instead of the pulse width control circuit 127 and the iris control circuit 125.

The dimming control circuit 134 controls the pulse width control circuit 135 and the pulse intensity control circuit 136 of the light source device 133 in addition to the control of the CCD driver 105 and the iris driver 104. The dimming control circuit 134 manages and controls the balance of dimming by the CCD shutter, the camera iris, and the light source based on the detection signal of the light amount detection circuit 103.

The pulse width control circuit 135 and the pulse intensity control circuit 136 generate the C
The pulse width and the pulse intensity of the illumination light are controlled using the received light amount information which is the light amount obtained by detecting the CD output and the opening information which is the opening amount of the iris 100 instructed by the iris driver 104. The pulse width control circuit 135
, The light source 128 is turned on and off in synchronization with the CCD element shutter, as in the second embodiment.

In the above configuration, the iris 1 on the CCD side
00 is provided for setting the depth of field,
In order to control the iris with priority, the amount of illumination is adjusted according to the opening amount of the iris 100. The following advantages are obtained by giving priority to iris. That is, the iris 10
By obtaining an appropriate brightness in a state where 0 is reduced as much as possible, a deep observation region can be obtained, and focus adjustment is not required even if the distance of the subject changes, so that operability is improved.

First, when the iris 100 is closed (opening amount is small) and the amount of light received by the CCD is small, the pulse width is narrowed as shown in FIG. And increase the pulse intensity of the illumination light. This prevents the image quality from deteriorating due to insufficient light quantity.

On the other hand, when the iris is open (the aperture is large) and the amount of light received by the CCD is too large, the pulse width is increased and the illumination light is increased as shown in FIG. Lower the pulse intensity. This prevents overexposure of the image due to excessive light quantity.

In the above control, both the pulse width and the pulse intensity are controlled so that the total amount of light energy of the light emission pulse is the same.

In the present embodiment, the illumination light blinks in synchronization with the CCD element shutter, and the pulse waveform is changed in accordance with the opening and closing of the iris, that is, control is performed so that the total energy amount of the emission pulse is constant. Therefore, burns due to illumination light can be prevented.

[Supplementary Note 1] The endoscope apparatus according to claim 1, further comprising means for controlling the amount of light incident on the solid-state imaging device, wherein the light-amount detection circuit includes an output of the solid-state imaging device. Means for detecting a brightness component of an image to generate a control signal, wherein the solid-state image sensor driving means drives the solid-state image sensor at a desired exposure time, controls reading of a signal, and generates the control signal. A driving unit that varies an exposure period of the solid-state imaging device in accordance with a dimming signal output by the unit; and a light source that emits illumination light in accordance with the exposure period by a timing signal output by the driving unit. And a light source emission period control unit for turning off the light during periods other than the above.

[Supplementary Note 2] In the endoscope apparatus according to Supplementary Note 1, the control means may be arranged between the solid-state imaging device and the objective optical system and measure an amount of light incident on the solid-state imaging device. An image-capturing-side diaphragm means for controlling an aperture amount according to a control signal of the generating means for adjusting; and an aperture amount according to a control signal of the generating means for adjusting the amount of illumination light emitted by the light source means Where the aperture of the imaging-side aperture is increased by the control signal to reduce the amount of illumination by reducing the aperture of the light-source-side aperture, and the control signal When the aperture of the imaging-side aperture is reduced, the aperture of the light-source-side aperture is opened to control to increase the amount of illumination.

[Supplementary Note 3] In the endoscope apparatus according to Supplementary Note 1, the light amount detection circuit is a unit that detects a light component of an image in an output of the solid-state imaging device and detects a received light amount. A driving unit for driving the solid-state imaging device for a predetermined exposure time to control reading of a signal; and the solid-state imaging device disposed between the solid-state imaging device and the objective optical system. An imaging-side aperture unit whose aperture is controlled in accordance with the amount of received light detected by the detection circuit in order to adjust the amount of light incident on the imaging circuit; and illuminating the illumination light emitted by the light source unit in a pulsed manner. Means for simultaneously variably controlling both the light emission pulse width and the light emission pulse intensity of the illumination light in accordance with the aperture of the aperture means.

[Supplementary Note 4] In the endoscope apparatus according to Supplementary Note 3, the variable control means may be configured when the aperture of the imaging-side stop means is small and the amount of received light detected by the detection circuit is insufficient. In the case where the light emission pulse width of the illumination light is narrow and the light emission pulse intensity is high, the amount of received light detected by the detection circuit is too large when the aperture of the imaging-side stop is large. Is to variably control the pulse width of the illumination light to be widened and the intensity of the light emission pulse to be weakened so that the total amount of the illumination light that emits the pulse is constant for each pulse.

[Supplementary Note 5] An endoscope apparatus having an objective optical system for forming an image of a subject, imaging means for taking a subject image formed by the objective optical system, and light source means for irradiating the subject with illumination light. A lighting control unit for turning on the illumination light of the light source unit only during an exposure period of the imaging unit.

[Supplementary Note 6] The endoscope apparatus according to Supplementary Note 5, further comprising an incident light amount limiting unit provided in front of the imaging unit, and a lighting time of the illumination light of the light source unit depending on a state of the incident light amount limiting unit. Lighting time control means for controlling
An illumination light quantity control means for controlling the illumination light quantity of the light source means is provided.

[0048]

According to the present invention, at least one of the amount of illumination light emitted from the light source means, the emission time of the illumination light, or the amount of light incident on the solid-state image sensor is controlled, and the object is heated by the illumination light. There is an effect that the living tissue can be prevented from being burned.

[Brief description of the drawings]

FIG. 1 is an overall block diagram of an endoscope apparatus.

FIG. 2 is a configuration diagram of a main part of the endoscope apparatus according to the first embodiment of the present invention.

FIG. 3 is a timing chart showing the operation of the endoscope apparatus of FIG. 2;

FIG. 4 is a configuration diagram of a main part of an endoscope apparatus according to a second embodiment of the present invention.

FIG. 5 is a timing chart showing the operation of the endoscope apparatus of FIG. 4;

FIG. 6 is a configuration diagram of a main part of an endoscope apparatus according to a third embodiment of the present invention.

FIG. 7 is a waveform chart for explaining the operation of the endoscope apparatus of FIG. 6;

[Explanation of symbols]

 1,95,121,131 endoscope device 2,99 solid-state imaging device 3,96 endoscope 4,97,122,132 CCU 6,98,123,133 light source device (light source means) 7 ... Subject 8... Objective optical system 103... Light quantity detection circuit 105..

──────────────────────────────────────────────────続 き Continuing from the front page (72) Nobuyuki Sakamoto, Inventor 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside O-Limpus Optical Co., Ltd. (72) Hideki Koyanagi 2-43-2, Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. (72) Inventor Akihiko Mochida 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. (72) Kotaro Ogasawara 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. (72) Shinji Yamashita, the inventor Shinbashi Yamashita 2-43-2, Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. Olympus Optical Co., Ltd. (56) References JP-A-4-341231 (JP, A) JP-A-2-20816 (J (P, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 23/26 A16B 1/06 G02B 23/24

Claims (1)

(57) [Claims] A light source unit that emits illumination light for illuminating a subject; an objective optical system that forms a subject image of the subject; a solid-state imaging device that captures the subject image formed by the objective optical system; A light amount detection circuit that detects a luminance component from an output signal of the solid-state imaging device, and based on the luminance component detected by the light amount detection circuit,
The drive signal for controlling the exposure period of the solid-state imaging device is
A solid-state imaging device driving circuit for sending out to the solid-state imaging device, and the light source unit flashing in synchronization with the driving signal for controlling the exposure period of the imaging device controlled by the solid-state imaging device driving circuit. A light source emission period control means for causing the light quantity detection circuit to be disposed on a front surface of the solid-state imaging device;
Aperture is controlled based on the luminance component detected by
An imaging-side aperture unit; and the light source device according to the opening amount of the imaging-side aperture unit.
Dimming control circuit for controlling the intensity of the illumination light emitted by the stage
An endoscope apparatus, comprising: