JPH07275192A - Endoscope apparatus - Google Patents

Abstract

PURPOSE:To provide the endoscope apparatus with which clear images can be provided regardlessly of the shape of an object. CONSTITUTION:Concerning this endoscope apparatus, light emitted from an xe lamp 3 is guided through a heat ray reflection mirror 4, diaphragm 5 and condenser lens 6 to a rod fiber 7a and a fiber bundle 7b provided inside a scope 2, an object S in the living body is illuminated with the light emitted from this fiber bundle 7b through an illumination lens 7c, and the image of the object S provided by this illumination is displayed on a television monitor 12 as a picture. At such a time, an ALC 41 detects the luminance distribution of the image signal and a light distribution board 13 is rotated by driving a motor 14 through a motor control circuit 15 based on this detected result so that the distribution characteristics of light emitted from the xe lamp 3 can be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus for inserting an electronic scope into a subject to illuminate a subject and displaying an image of the illuminated subject as an image, and particularly to illuminating the subject. The present invention relates to an endoscope apparatus including means for controlling the light distribution characteristic of light.

[0002]

2. Description of the Related Art As an endoscope device, there is known a device in which an electronic scope is inserted into a living body, an image of the inside of the living body is picked up by an image pickup element provided at the tip of the scope and displayed on a monitor. In particular, a solid-state image sensor (CCD image sensor;
Since an image with extremely high resolution can be obtained by simply using (CCD), it is frequently used for observing various diagnostic sites in the living body.

FIG. 11 shows an example of such an endoscope apparatus. According to FIG. 11, x _e having a lamp power supply 30a
The light from the lamp 30 is removed from the heat ray through the heat ray reflecting mirror 31, and then enters the blind diaphragm 32. The diaphragm 32 adjusts the total amount of light emitted from the diaphragm 32 by opening and closing the diaphragm 32a under the control of ALC described later. The light whose amount of light is adjusted by the diaphragm 32 is condensed by the condensing lens 33, and then is transmitted through the rod fiber 34 to the illumination fiber bundle 35.
Incident on.

The light thus passing through the illumination fiber bundle 35 and emitted from the tip thereof illuminates the subject S via the illumination lens (usually a concave lens) 35a.

The illuminated subject S is imaged by the objective lens 36 on the image pickup surface 37a (three primary colors or complementary color filter array is pasted on the front surface) of the CCD 37, and an image signal (video signal) of the three primary colors or complementary colors is formed. To be converted. This image signal is amplified by an amplifier 38 and then input to a camera control unit (hereinafter referred to as CCU) 39.

The image signal input to the CCU 39 is converted into, for example, a TV signal of NTSC system, and the TV monitor 4
Sent to 0. As a result, the image of the subject S is displayed on the television monitor 40.

By the way, in the endoscope apparatus, the television monitor 4
The brightness of 0 on the screen is controlled by adjusting the amount of light that illuminates the subject S. That is, in the present configuration, in order to perform this light amount adjustment, the diaphragm 32 described above is used.
And an ALC (Auto Light Contr) that controls the diaphragm 32.
ol) 41.

The ALC 41 refers to the image signal sent to the CCU 39, and presets a photometric area on one screen of the television monitor 40 (for example, the entire screen, a circular area at the center of the screen, and a donut shape at the peripheral area of the screen). The luminance level of the signal corresponding to the area) is detected to control the aperture angle of the aperture 32a in the aperture 32.

For example, when the circular area in the central portion of the screen is set as the photometric area and the circular area in the central portion of the screen of the image displayed on the television monitor 40 becomes dark, the ALC 41 determines the brightness of the circular area. Detect the level,
Since the diaphragm 32a of the diaphragm 32 is controlled to be opened by a required amount, the entire screen displayed on the television monitor 40 becomes bright and the central part of the screen becomes easy to see.

[0010]

However, in the above-described brightness control on the screen, even if a part of the screen (for example, the central portion of the screen) is dark, the brightness of the entire screen is uniformly bright. I got it. In other words, the light distribution (illumination light distribution characteristics (in other words, the light distribution of the entire screen) is adjusted simply by controlling the brightness of the entire screen by adjusting the total amount of light that illuminates the subject (illumination light). Characteristics)) was not adjusted.

Therefore, the optimum amount of light is adjusted for a flat subject, but when observing an uneven subject such as a subject protruding only at the center or a cylindrical subject, the light amount is adjusted. There was a problem that it was difficult.

[0012] For example, when observing a gastric corner portion (a subject protruding only in the central portion) with an upper endoscope, only the central portion becomes very bright, while the peripheral portion becomes very dark, and the lower portion. On the contrary, when observing the inside of the large intestine (cylindrical object) with an endoscope, on the contrary, only the peripheral part becomes very bright, but the central part becomes very dark. For this reason, halation occurs in a very bright part of the screen, and conversely, black shadows and the like occur in a very dark part of the screen.

As described above, in the conventional endoscope apparatus, there is a possibility that the image is deteriorated due to the shape of the subject and the visibility is lowered.

The present invention has been made in view of the above circumstances, and provides an endoscope apparatus which can obtain a clear image regardless of the shape of a subject by controlling the distribution characteristic (light distribution characteristic) of illumination light. Its purpose is to provide.

[0015]

In order to achieve the above object, according to the invention described in claim 1, the light emitted from the light source is guided to the optical transmission means provided in the scope through the lens system, In the endoscope device configured to illuminate the subject in the living body with the light emitted from the light transmission means and display the image of the subject obtained by this illumination as an image on a monitor, the light is emitted from the light source. And a control means for controlling the light distribution characteristic.

In particular, in order to achieve the above object, according to the invention described in claim 2, the control means includes the light source for changing the distribution characteristic of the light for illuminating the subject as the light source and the light transmission means. It has a structure in which it is manually and detachably inserted between the two.

Particularly, in the invention described in claim 3, the light distribution body forms at least one light distribution pattern.

Further, according to the invention described in claim 4, the lens system has a condenser lens for condensing the light emitted from the light source, and the light transmission means is the condenser lens. The light distribution plate is inserted between the condenser lens and the optical fiber, as well as having an optical fiber for transmitting the light condensed by the optical fiber to the tip of the scope.

On the other hand, in order to achieve the above object, according to the invention described in claim 5, the control means comprises a light distribution body for changing the distribution characteristic of the light illuminating the subject and the light transmission with the light source. And a manual control means capable of manually controlling the light distribution characteristic of the light distribution body.

Further, in order to achieve the above object, according to the invention described in claim 6, the control means includes a light distribution body for changing a distribution characteristic of light for illuminating the subject and the light transmission with the light source. In addition to having a structure interposed between the means and the means, it has an automatic control means for automatically controlling the light distribution characteristics of the light distribution body.

In particular, in the invention described in claim 7, the automatic control means detects the luminance distribution of the image based on the image of the subject, and the luminance distribution detected by the detecting means. And a setting means for setting the light distribution characteristic of the light distributor.

Further, in the invention described in claim 8, in particular, the light distribution body is provided with at least a plurality of light distribution patterns having their centers on the same circle set with respect to the center of the entire substrate. It is a light distribution plate.

Further, in the invention described in claim 9, at least one of the plurality of light distribution patterns is an opening pattern for transmitting light entirely.

Further, in the invention described in claim 10, among the plurality of light distribution patterns, the light distribution pattern excluding the opening pattern is a pattern having an annular light-shielding portion, and a small circular light-shielding portion in the central portion. Any of a pattern having a portion and a pattern having an annular light-shielding portion in the central portion is included.

Particularly, in the invention described in claim 11, the setting means includes a motor for rotating the light distribution plate about the center of the substrate and a motor control means for controlling a rotation angle of the motor. The motor control means automatically rotates the motor by a required angle based on the luminance distribution detected by the detection means, selects one of the plurality of light distribution patterns, and selects the light source and the light transmission means. It is configured to be inserted on the optical path between the two.

Further, in the invention described in claim 12, in particular, the lens system has a condenser lens for condensing the light emitted from the light source, and the optical transmission means is constituted by the condenser lens. In addition to having an optical fiber that transmits the condensed light to the tip of the scope, the light distribution plate is interposed between the condensing lens and the optical fiber. Is
It is formed by vapor-depositing a metal film on a glass plate arranged on the light distribution plate.

On the other hand, in the fourteenth aspect of the present invention, the light distribution body is a liquid crystal shutter having a plurality of electrode patterns formed thereon.

[0028]

According to the endoscope apparatus of the first aspect, the brightness of the image displayed on the monitor on the screen is adjusted by the light emitted from the light source by the control means (hereinafter, also referred to as illumination light). This is performed by controlling distribution characteristics (hereinafter, also referred to as light distribution characteristics).

Particularly, in the endoscope apparatus according to the second aspect, when a certain region R on the screen has halation, a light distribution pattern is formed so that the brightness of the region R is reduced. A light distribution body is prepared, and an operator or the like inserts the light distribution body between the light source and the optical transmission means, for example, between the condenser lens and the optical fiber.

Therefore, the light emitted from the light source is changed by this light distribution body to have a distribution characteristic such that the brightness of the region R is reduced, and the light is emitted to the subject in the living body through the lens system and the optical transmission means. It is supposed to be illuminated.

In particular, in the endoscope apparatus according to the fifth aspect, the light distribution body that changes the distribution characteristic of the light that illuminates the subject is inserted between the light source and the light transmission means. Further, a manual control means for controlling the light distribution characteristic of the light distribution plate is provided.

For example, when a certain area R on the screen is causing halation, the operator operates the manual control means so that the light distribution characteristic of the light distribution plate becomes a characteristic in which the brightness of the area R is reduced. To do.

Therefore, the light emitted from the light source is changed by the light distribution plate to have a distribution characteristic such that the brightness of the region R is reduced, and the subject in the living body is illuminated through the lens system and the optical transmission means. It is supposed to be done.

Further, in the endoscope apparatus according to the sixth aspect, as the light distribution body, for example, a plurality of light distribution patterns having the centers on the same circle set with respect to the center of the entire substrate (for example, (Aperture pattern for transmitting light entirely, a pattern having an annular light-shielding portion, a pattern having a small circular light-shielding portion in the central portion, a pattern having an annular light-shielding portion in the central portion, etc. are formed) Is provided, and the light distribution plate is interposed between the light source and the optical transmission means, for example, between the condenser lens and the optical fiber. The light-shielding portion is formed, for example, by depositing a metal film on a glass plate arranged on the light distribution plate.

Further, in this endoscope apparatus, a motor for rotating the light distribution plate about the center of the substrate as an automatic control means for automatically controlling the light distribution characteristic of the light distribution body, and the rotation of this motor. A setting unit including a motor control unit for controlling the angle and a detection unit for detecting the luminance distribution of the image displayed on the monitor are provided.

For example, when the central portion R ₁ on the screen has halation, the detection means detects the luminance distribution of the image displayed on the monitor, and the detection result is sent to the motor control means. In the luminance distribution sent to the motor control means, since the luminance of the signal corresponding to the central portion of the monitor is higher than that of the peripheral portion, the motor is driven by the motor control means, and a small circular light shield is provided in the central portion. The light distribution plate rotates so that the pattern having the portions (that is, the pattern in which the illumination light corresponding to the central portion on the screen is blocked) is inserted on the optical path between the condenser lens and the optical fiber.

Therefore, the light emitted from the light source is changed by the light distribution pattern of the light distribution plate to a distribution characteristic such that the brightness of the central region is reduced, and the light is emitted through the lens system and the light transmitting means in the living body. Is illuminated by the subject.

In the endoscope device according to the fourteenth aspect, a liquid crystal shutter having a plurality of electrode patterns is used as the light distribution body. By selecting a desired electrode pattern from the electrode patterns of the liquid crystal shutter and applying a voltage, it is possible to block or transmit the light incident on the liquid crystal shutter. Therefore,
It is possible to control the light distribution characteristics of the light that illuminates the subject through the liquid crystal shutter.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an endoscope apparatus according to the present invention will be described below with reference to the accompanying drawings.

The first embodiment will be described with reference to FIGS.

An endoscope apparatus 1 shown in FIG. 1 guides light for illuminating a subject and transmits an image of a subject S illuminated by the light (hereinafter, also referred to as illumination light) as an electronic image. Equipped with 2.

That is, the electronic scope 2 has a x _e lamp 3 which is a light source, a heat ray reflecting mirror 4 for removing unnecessary heat rays, a blind diaphragm 5 for adjusting the total amount of light, and a condenser. Condensing lens 6, rod fiber 7a for guiding light, and fiber bundle 7b for illumination
And an illumination lens 7c for expanding the emission angle of light. The heat ray reflection mirror 4, the diaphragm 5, and the condenser lens 6 form the lens system of the present invention, and the rod fiber 7a and the illumination fiber bundle 7b form the optical fiber of the present invention.

The condenser lens 6 is constructed so as to condense the light, the amount of which has been adjusted by the diaphragm 5, at the entrance end of the illumination fiber bundle 7b where the rod fiber 7a is formed in advance. The lighting fiber bundle 7b is
The illumination lens 7c is provided up to the tip of the electronic scope 2 and guides the condensed light to the tip of the electronic scope 2.
It is designed to be emitted to. The illumination lens 7c is usually a concave lens and is provided at the tip of the electronic scope 2. Then, when the light emitted from the illumination fiber bundle 7b is incident, the subject S is expanded while expanding the emission angle.
It is designed to illuminate.

On the other hand, the tip of the electronic scope 2 is also provided with an objective lens 8, a solid-state image sensor (hereinafter referred to as CCD) 9 and an amplifier 10. A camera control unit (hereinafter referred to as CCU) 11 and a television monitor 12 are connected to the output side (hand side of the scope 2) of the amplifier 10.

The objective lens 8 is adapted to image the reflected light from the illuminated subject on the image pickup surface 9a of the CCD 9. The CCD 9 has a filter array of three primary colors or complementary colors (not shown) attached on the front surface of the image capturing surface 9a, and an image of the subject S formed on the image capturing surface 9a is an image signal (video signal) of three primary colors or complementary colors. And is sent to the amplifier 10. Further, the amplifier 10 amplifies the sent image signal with low noise and sends it to the CCU 11.

The CCU 11 is provided with a frame memory (not shown) having a storage area corresponding to one screen of the television monitor 12, a matrix circuit, a mixing circuit and the like, and stores the sent image signal in the frame memory. .

The image signal stored in the frame memory is read out for each frame in synchronization with the synchronizing signal on the television side and converted into, for example, an NTSC television signal via a matrix circuit and a mixing circuit. After that, it is sent to the television monitor 12. As a result, the image of the subject S is displayed on the television monitor 12.

On the other hand, the endoscope apparatus 1 includes the television monitor 12
The light distribution characteristic on the screen is adjusted by controlling the light distribution of the illumination light that illuminates the subject S. That is, in this configuration, in order to perform the light distribution control, the light distribution plate 13 inserted between the condenser lens 6 and the incident end of the fiber bundle 7b, and the motor 14 that rotatably supports the light distribution plate 13 are provided. And a motor control circuit 15 for controlling the rotation angle and the like of the motor 14, and the motor control circuit 15
ALC (Auto Light Con-trol) for controlling
6 and.

The light distribution plate 13 has a light distribution pattern a for changing the distribution characteristic (light distribution characteristic) of light incident on the light distribution plate 13.
_{1 to} d ₁ are formed. That is, this light distribution plate 13
2 is a metal disc as shown in FIG. 2, and a plurality of circular openings (four in this embodiment) are formed in the disc. The centers of the four openings a to d are located on the same circle set with respect to the center of the disc, and the diameter thereof is at least larger than the beam diameter of the illumination light incident on the light distribution plate 13. Has become.

Among the openings a to d, the opening a is
It is an opening pattern (light distribution pattern a ₁ ) that completely transmits incident light. In addition, light-shielding glass plates 13a to 13c formed by vapor-depositing a metal film on a circular glass plate having substantially the same size as the openings are incorporated in the openings b to d. In addition, in FIG. 2 (the same applies to FIG. 3 described later),
The shaded portions of the light-shielding glass plates 13a to 13c are regions for shielding or attenuating light (hereinafter, simply referred to as light-shielding regions). When light is shielded, a thick metal film is provided on the glass plates 13a to 13c. , Is thinly deposited.

As shown in FIG. 3A, the opening b is provided with an annular light-shielding region (inner diameter: w _b2 ) whose outer diameter w _b1 is substantially the same as the opening diameter of the opening b. A light distribution pattern b ₁ is formed.

As shown in FIG. 3B, the opening c is provided with an annular light-shielding region (inner diameter: w _c2 ) whose outer diameter w _c1 is substantially the same as that of the opening c. Furthermore, its inner diameter w
providing a circular shading area c having a diameter w _c3 shorter than _c2 ,
The light distribution pattern c ₁ is formed as a whole.

As shown in FIG. 3, the opening d is provided with an annular light-shielding region (inner diameter: w _d2 ) whose outer diameter w _d1 is substantially the same as the opening diameter of the opening c. An annular light-shielding region (inner diameter: w _d4 ) having an outer diameter w _d3 shorter than the inner diameter w _d2 of the light-shielding region is provided, and the light distribution pattern d ₁ is formed as a whole.

Now, the light distribution function of each of the light distribution patterns b _{1 to} d ₁ will be described.

First, the light distribution pattern b ₁ will be described. In the light distribution pattern b ₁ , the incident angle θ to the fiber bundle 7 b is “θ ≦ θ ₁ (θ ₁ = tan ⁻¹ (w _b2 / 2
D)) ”is incident as it is, and the others are shielded. Therefore, passing through this pattern,
Further, as shown in FIG. 4, the light distribution intensity of the light beam emitted through the fiber bundle 7b and the illumination lens 7c is as follows.
The area corresponding to the central portion of the screen is strong, and the peripheral portion has a weak characteristic.

Next, the light distribution pattern c ₁ will be described. In the light distribution pattern c ₁ , the incident angle θ to the fiber bundle 7 b is “θ _1a ≦ θ ≦ θ _2a (θ _1a = tan ⁻¹ (w _c3 / w
2D); θ _2a = tan ⁻¹ (w _c2 / 2D)) ”is incident as it is, and rays incident at other incident angles are blocked. Therefore, a light ray that passes through this pattern and further passes through the fiber bundle 7b is also emitted from its emission end at an emission angle of θ _1a <θ <θ _2a , is incident on the illumination lens 7c, and is further emitted from the illumination lens 7c. As shown in FIG. 5, the light distribution intensity of the generated light has a donut-like characteristic in which the region corresponding to the central portion of the screen is weak and the peripheral portion thereof is strong.

Finally, the light distribution pattern d ₁ will be described. In the light distribution pattern d ₁ , the incident angle θ to the fiber bundle 7b is “θ ≦ θ _1b , θ _2b ≦ θ ≦ θ _3b (θ _1b = tan ⁻¹
(W _d4 / 2D); θ _2b = tan ⁻¹ (w _d3 / 2D); θ _3b =
A light beam of "tan ^-1 (w _d2 / 2D)" is directly incident, and a light beam incident at any other incident angle is blocked. Therefore, a ray that passes through this pattern and further passes through the fiber bundle 7b will also have θ ≦ θ
_1b and θ _2b ≦ θ ≦ θ _3b are emitted from the emission end at an emission angle θ and are incident on the illumination lens 7c.
Further, as shown in FIG. 6, the light distribution intensity of the light beam emitted from the illumination lens 7c has a characteristic that the region corresponding to the screen central portion and the screen edge portion is strong and the intermediate portion thereof is weak.

By changing the dimensions (w _{b1 to} w _d4 ) of the light shielding area, it is possible to change the widths of the light illuminating area and the light illuminating area of the subject S.

The center of the light distribution plate 13 is the motor 1.
It is joined to the rotating shaft of No. 4.

The motor 14 mounts the light distribution plate 13 on its opening a.
It is configured to be rotatable so that the locus connecting the centers of d to d passes through the straight line connecting the center of the condenser lens 6 and the center of the fiber bundle 7b, that is, the optical axis. In addition,
Normally, the center of the opening a is located on the optical axis (this state is the initial position).

Further, the motor control circuit 15 has the ALC1
The rotation timing of the light distribution plate 13 based on the control from 6,
It has a function of controlling the rotation angle and the like.

The ALC 16 refers to the frame memory of the CCU 11 and detects the brightness level of the image signal stored in this frame memory to detect a two-dimensional brightness distribution. Then, the rotation angle of the light distribution plate 13 is determined according to the brightness distribution and is sent to the motor control circuit 15.

The ALC 16 can also adjust the light amount of the entire screen of the television monitor 12 by sending a control signal to the diaphragm 5 to control the diaphragm angle of the diaphragm 5.

The light distribution plate 13, the motor 14, the motor control circuit 15, and the ALC 16 in this embodiment are the same as those in claim 1.
Form the described control means. Further, the ALC 16 forms the detecting means described in claim 7, and the motor control circuit 15 forms the motor controlling means described in claim 7.

Next, the operation of this embodiment will be described.

When a diagnosis is made using the endoscope apparatus 1 shown in FIG. 1, the tip of the electronic scope 2 is inserted through the mouth or anus of the subject. Then, the tip of the scope 2 is moved to near the desired subject S.

At this time, the light emitted from the x _e lamp 3 is
After the heat ray is removed through the heat ray reflecting mirror 4, the heat ray enters the condenser lens 6 through the diaphragm 5. The light that has entered the condenser lens 6 enters the illumination fiber bundle 7b through the opening a of the light distribution plate 13 and the rod fiber 7a. And the fiber bundle 7b for illumination
Is guided to the tip of the scope 2 and emitted from the tip of the fiber bundle 7b.

Here, FIG. 7 shows an example of the light distribution characteristics of the illumination light emitted from the illumination fiber bundle 7b.
In FIG. 7, the horizontal axis is the angle from the optical axis on an arbitrary plane including the optical axis (emission angle: emission angle from the optical axis to the right side; RIGH
T, the emission angle LEFT from the optical axis to the left side, and the vertical axis shows the power of the light emitted at a constant emission angle from the optical axis. The range of the emission angle of the emitted light is the numerical aperture (NA (Numerical Apertu
re)). That is, as shown in FIG.
It can be seen that the power of the light emitted from the illumination fiber bundle 7b changes depending on the emission angle thereof, and as a result, the light distribution characteristic of the illumination light also changes.

On the other hand, FIG. 8 shows the light L ₁ emitted from the light source 3.
Is condensed by the condenser lens 6, is incident on the illumination fiber bundle 7b, is guided through the illumination fiber bundle 7b, and is then emitted from the emission end of the fiber bundle 7b. In this embodiment, the range from the NA of the fiber bundle 7b to the emission angle θ _A is θ _Amax (LIGHT, LEFT) = 35 °.

At this time, as shown in FIG. 8, the light rays incident on the fiber bundle 7b at the angle θ _B are emitted from the exit end of the fiber bundle 7b at the same angle θ _B (= θ _A ).

Therefore, if the incident angle θ _B of the light ray incident from the incident end of the fiber bundle 7b is controlled, the emission angle θ _{A of the} light ray emitted from the emission end of the fiber bundle 7b, that is, the light distribution characteristic of the illumination light is controlled. It becomes possible to do.

The light emitted from the fiber bundle 7b illuminates the subject S via the illumination lens 7c. At this time, the current subject S is assumed to be a flat subject having no unevenness.

The light reflected from the illuminated subject S is
An image is formed on the image pickup surface 9a of the CCD 9 through the objective lens 8 and converted into an image signal. This image signal is sent to the amplifier 10
And is stored in the frame memory of the CCU 11.

This image signal is read out as a television signal in synchronization with the synchronizing signal on the television side, and the television monitor 12
Sent to. As a result, the subject S is displayed on the TV monitor 12.
Image is displayed.

At this time, the ALC 16 is constantly in the CCU 11
The two-dimensional luminance distribution is detected by referring to the frame memory. Now, since the subject S is flat, the luminance distribution is uniform. Therefore, no control signal is sent to the motor control circuit 15, and the light distribution plate 13 remains in the initial position.

On the other hand, when observing a subject S ₁ protruding only at the central portion such as the gastric corner portion when moving the scope 2 when performing an upper gastrointestinal examination, the image signal stored in the frame memory of the CCU 11 is used. Indicates that the luminance level of the signal corresponding to the central portion of the screen is high, and the luminance level of the signal corresponding to the peripheral portion (hereinafter, referred to as the peripheral portion of the screen) around the central portion is low.

At this time, the ALC 16 refers to the frame memory to detect the two-dimensional luminance distribution. Then, a control signal is sent to the motor control circuit 15 to rotate the motor 14 to rotate the light distribution plate 13 so that the opening c, that is, the center of the light distribution pattern c ₁ is located on the optical axis.

The light distribution pattern c ₁ has the light distribution characteristic shown in FIG. 5, that is, the central portion of the screen is weak and the peripheral portion of the screen is strong. It is possible to suppress and increase the brightness of the peripheral portion of the screen. Therefore, even with respect to the subject S ₁ having a projecting shape in the central part such as a stomach angle, halation in the central part of the screen and black crushing in the peripheral part are prevented, and the projecting part and other parts have substantially the same brightness. Can be obtained.

Further, when performing a lower gastrointestinal tract examination, the scope 2 is moved to move a cylindrical subject S ₂ such as the lumen of the large intestine.
When observing (the peripheral area of the screen is at a short distance and the central area of the screen is at a long distance), the image signal stored in the frame memory of the CCU 11 has a high luminance level of the signal corresponding to the peripheral area of the screen and corresponds to the central area of the screen. The signal brightness level is low.

At this time, the ALC 16 refers to the frame memory to detect the two-dimensional luminance distribution. Then, a control signal is sent to the motor control circuit 15 to rotate the motor 14 to rotate the light distribution plate 13 so that the opening b, that is, the center of the light distribution pattern b ₁ is located on the optical axis.

Since the light distribution pattern b ₁ has the light distribution characteristics shown in FIG. 4, that is, the central portion of the screen is strong and the peripheral portion of the screen is weak, the brightness of the peripheral portion of the screen is suppressed, The brightness of the central part of the screen can be increased. Therefore, it is possible to prevent halation in the peripheral portion of the screen and black shadow in the central portion of the cylindrical subject S ₂ such as the lumen of the large intestine.

Furthermore, during an upper gastrointestinal tract examination, the scope 2 is moved to move the object S ₃ such as a pylorus (a donut-shaped object or a screen of a long distance in the central portion of the screen and a short distance in the peripheral portion of the screen). When observing the long distance), CCU1
In the image signal stored in the first frame memory, the luminance level of the signal corresponding to the peripheral portion of the screen is high, and the luminance level of the signal corresponding to the central portion and the end portion of the screen is low.

At this time, the ALC 16 refers to the frame memory to detect the two-dimensional luminance distribution. Then, a control signal is sent to the motor control circuit 15 to rotate the motor 14 to rotate the light distribution plate 13 so that the opening d, that is, the center of the light distribution pattern d ₁ is located on the optical axis.

The light distribution pattern d ₁ has the light distribution characteristics shown in FIG. 6, that is, the screen center portion and the screen edge portion are strong, and the middle screen peripheral portion has a weak characteristic. The brightness of the center of the screen and the brightness of the end of the screen can be increased. Therefore, even with respect to the subject S ₃ such as the pylorus, it is possible to prevent halation at the peripheral portion of the screen and black underexposure at the central portion and the end portion of the screen.

The light distribution patterns b ₁ , c ₁ , d _{1 described above}
Besides, the light distribution plate 13 having various light distribution patterns can be formed according to the complicated shape of the subject to control the light distribution. Accordingly, it is possible to avoid halation on the screen, blackout, and the like due to the special shape of the subject S, and it is possible to easily obtain a high quality endoscopic image. As a result, the examination time is shortened and the burden on the operator and the patient is reduced.

The light distribution patterns b ₁ , c of the light distribution plate 13
The dimensions (w _{b1 to} w _d4 ) of the light-shielding glass plates 13a to 13c at ₁ and d ₁ are the angles of incidence (θ) that are desired to be shielded based on the dimensions of the above-mentioned special shape such as the stomach angle and the lumen of the large intestine.
_{1 to} θ _3b ).

Further, in this embodiment, the ALC 16 is CC
Although the light distribution pattern is automatically selected by referring to the U11 frame memory to control the light distribution characteristic of the illumination light, the present invention is not limited to this.
A switch (not shown) is provided, and the operator manually operates the switch while watching the television monitor 12 to drive the motor 14 to rotate the light distribution plate 13,
The light distribution pattern may be manually selected by the light distribution plate 13 such as selecting the light distribution pattern. The motor 14 at this time forms the manual control means of the fifth aspect.

Further, in this embodiment, the light distribution plate 13 on which the light distribution pattern is formed is rotated by the motor 14 to automatically select the light distribution pattern, but the present invention is not limited to this. For example, while the operator is watching the TV monitor 12, the operator manually operates the light distribution plate 13 on which at least one light distribution pattern such as a slide is formed between the x _e lamp 3 and the fiber bundle 7b (the condenser lens 6 and the fiber bundle). 7b) or the like).

Next, a second embodiment will be described with reference to FIGS. 9 and 10.

The endoscope apparatus 1a shown in FIG. 9 controls the light distribution, so that the liquid crystal shutter 17 inserted between the condenser lens 6 and the incident end of the fiber bundle 7b, the switching circuit 18a, and the power supply circuit. And a liquid crystal shutter control circuit 18 whose main part is 18b.

The liquid crystal shutter 17 has a structure in which a liquid crystal having a thickness of, for example, several μm to 10 μm is sandwiched between two glass substrates. Then, as shown in FIG. 10, a plurality of concentric electrode patterns E are printed on this glass plate. The area of the liquid crystal shutter 17 on which the electrode pattern E is printed can transmit and block the light incident on the area. That is, the incident light is transmitted to the electrode pattern E when no voltage is applied, and the incident light is blocked when a voltage is applied. The liquid crystal shutter 17 is inserted so that the center of the electrode pattern E is located on the optical axis, and the maximum electrode pattern Ea is formed to be slightly larger than the beam diameter of the illumination light incident on the liquid crystal shutter 17. ing.

Signal lines are connected to the respective electrode patterns Ea to Ej printed on the liquid crystal shutter 17. This signal line is input to the switching circuit 18 a of the liquid crystal shutter control circuit 18. The switching circuit 18a selects a required electrode pattern E based on a control signal from the ALC 16 (a plurality of patterns can be selected).
Then, the signal line of the selected electrode pattern E and the signal line of the power supply circuit 18b are connected, and the voltage supplied from the power supply circuit 18b is applied to the electrode pattern E. Since the other configurations are the same as the configurations shown in FIG. 1, the description thereof will be omitted.

Next, the operation of this embodiment will be described.

In this embodiment, in order to control the distribution of the illumination light, the electrode pattern E of the liquid crystal shutter 17 is selected and a voltage is applied to block the illumination light passing through the pattern E portion.

For example, in the case of observing a subject S ₁ protruding only in the central portion such as the corner of the stomach, ALC16
Detects the two-dimensional luminance distribution of the image signal by referring to the frame memory (the luminance level of the signal corresponding to the central portion of the screen is high and the luminance level of the signal corresponding to the peripheral portion thereof is low). . Then, the switching circuit 18a
To drive the switching circuit 18a. The switching circuit 18a selects the electrode patterns Ea and Ei to Ej according to the control signal and applies a voltage. As a result, the liquid crystal shutter 17 is moved to the position shown in FIG.
A light distribution pattern similar to the light distribution pattern b ₁ shown in (b) is formed. That is, the light distribution pattern formed by the liquid crystal shutter 17 has the light distribution characteristics shown in FIG. 5, that is, the central portion of the screen is weak and the peripheral portion thereof is strong in a donut shape. It is possible to suppress the brightness of the central part and increase the brightness of the peripheral part of the screen. Therefore, even with respect to the subject S ₁ having a projecting shape in the central part such as the stomach angle, halation in the central part of the screen and blackening of the peripheral part are prevented, and the projecting part and other parts have substantially the same brightness. Can be obtained.

As described above, in this embodiment, the electrode pattern E is appropriately selected by the switching circuit 18a based on the control signal from the ALC 16, so that the above-mentioned light distribution patterns b _{1 to} d ₁ are obtained by the liquid crystal shutter 17. It becomes possible to form a similar light distribution pattern, and the subject S
The light distribution can be controlled according to the shape of the. In addition, not only the light distribution patterns b _{1 to} d ₁ but also a desired light distribution pattern can be formed by appropriately selecting the electrode pattern E. Further, the shape of the electrode pattern E (concentric circle shape) formed in advance can be formed. ) Can also be formed in a desired shape according to the complicated shape of the subject.
Therefore, it is possible to avoid halation on the screen, blackout, and the like due to the special shape of the subject S, and it is possible to easily obtain a high-quality endoscopic image. As a result, the examination time is shortened and the burden on the operator and the patient is reduced.

[0097]

As described above, according to the endoscope apparatus of the present invention, even in the case of a subject having a special shape with large irregularities,
It is possible to control the distribution characteristics (light distribution characteristics) of the illumination light according to its shape, rather than uniformly controlling the intensity of the illumination light corresponding to the entire screen. It is possible to avoid the above halation and blackout.

As a result, even if the subject has a special shape, a high quality endoscopic image can be easily obtained in a short examination time. Further, it is possible to reduce the burden on the operator and the patient who is the subject due to the reduction in the examination time.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an endoscope apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a light shielding plate in the first embodiment.

FIG. 3 is a diagram showing a light distribution pattern formed on a light shielding plate.

FIG. 4 is a diagram illustrating a light distribution function based on a light distribution pattern b ₁ .

FIG. 5 is a diagram illustrating a light distribution function based on a light distribution pattern c ₁ .

FIG. 6 is a diagram illustrating a light distribution function based on a light distribution pattern d ₁ .

FIG. 7 is a graph showing an example of light distribution characteristics of illumination light emitted from a fiber bundle.

FIG. 8 is a diagram showing a relationship between an incident angle of light incident on the fiber bundle and an emission angle of light emitted from the fiber bundle.

FIG. 9 is a schematic configuration diagram of an endoscope apparatus according to a second embodiment of the present invention.

FIG. 10 is a schematic configuration diagram of a liquid crystal shutter and a liquid crystal shutter control circuit according to a second embodiment.

FIG. 11 is a schematic configuration diagram of a conventional endoscope apparatus.

[Explanation of symbols]

1 Endoscope Device 1a Endoscope Device 2 Electronic Scope 3 x _e Lamp 4 Heat Ray Reflecting Mirror 5 Aperture 6 Condensing Lens 7a Rod Fiber 7b Fiber Bundle 7c Illuminating Lens 8 Objective Lens 9 CCD 9a Imaging Surface 10 Amplifier 11 CCU 12 TV Monitor 13 Light-shielding plate 13a Light-shielding glass plate 13b Light-shielding glass plate 13c Light-shielding glass plate 14 Motor 15 Motor control circuit 16 ALC 17 Liquid crystal shutter 18 Liquid crystal shutter control circuit 18a Switching circuit 18b Power supply circuit a _{1 to} d ₁ Light distribution pattern S subject

Claims (14)

[Claims] 1. A light emitted from a light source is guided through a lens system to a light transmission means provided in a scope, and the light emitted from the light transmission means illuminates a subject in a living body and the illumination. An endoscope apparatus configured to display the image of the subject obtained by the above as an image on a monitor, comprising: a control unit for controlling distribution characteristics of light emitted from the light source. apparatus. 2. The control means has a structure in which a light distribution body for changing a distribution characteristic of light for illuminating the object is manually and detachably interposed between the light source and the light transmission means.
The endoscopic device described. 3. The endoscope apparatus according to claim 2, wherein the light distribution body is a light distribution plate on which at least one light distribution pattern is formed. 4. The lens system has a condenser lens for condensing the light emitted from the light source, and the light transmitting means transmits the light condensed by the condenser lens to the tip of the scope. The endoscopic device according to claim 3, further comprising: an optical fiber, and the light distribution plate interposed between the condenser lens and the optical fiber. 5. The control means has a structure in which a light distribution body that changes a distribution characteristic of light for illuminating the object is inserted between the light source and the light transmission means, and the light of the light distribution body is lighted. The endoscope apparatus according to claim 1, further comprising a manual control unit capable of manually controlling the distribution characteristic of the. 6. The control means has a structure in which a light distribution body for changing distribution characteristics of light for illuminating the object is inserted between the light source and the light transmission means, and the light of the light distribution body is lighted. The endoscope apparatus according to claim 1, further comprising an automatic control unit that automatically controls the distribution characteristics of the. 7. The automatic control means detects a brightness distribution of an image based on the image of the subject, and a light distribution characteristic of the light distributor based on the brightness distribution detected by the detection means. The endoscope apparatus according to claim 6, further comprising setting means for setting. 8. The light distribution plate according to claim 6, wherein the light distribution body is a light distribution plate provided with at least a plurality of light distribution patterns having centers on the same circle set with respect to the center of the entire substrate. Endoscopic device. 9. The endoscope apparatus according to claim 8, wherein at least one of the plurality of light distribution patterns is an opening pattern that allows light to pass through entirely. 10. The light distribution pattern of the plurality of light distribution patterns excluding the opening pattern is a pattern having an annular light-shielding portion, a pattern having a small circular light-shielding portion in the central portion, and a circle in the central portion. The endoscope apparatus according to claim 9, comprising any one of patterns having an annular light shielding portion. 11. The setting means includes a motor for rotating the light distribution plate about the center of the substrate and a motor control means for controlling a rotation angle of the motor, and the motor control means includes the detection means. The motor is automatically rotated by a required angle on the basis of the brightness distribution detected by, and any one of the plurality of light distribution patterns is selected and is inserted on the optical path between the light source and the light transmission means. The endoscope apparatus according to claim 10, configured as described above. 12. The lens system has a condenser lens for condensing the light emitted from the light source, and the light transmitting means transmits the light condensed by the condenser lens to the tip of the scope. The endoscope apparatus according to claim 11, further comprising an optical fiber, wherein the light distribution plate is interposed between the condenser lens and the optical fiber. 13. The endoscope apparatus according to claim 10, wherein the light shielding portion is formed by vapor-depositing a metal film on a glass plate arranged on the light distribution plate. 14. The endoscope apparatus according to claim 6, wherein the light distribution body is a liquid crystal shutter having a plurality of electrode patterns formed thereon.