JPS61175609A - Stop device of light source device for endoscope - Google Patents

Abstract

PURPOSE:To easily perform an accurate diagnosis by varying the intensity of illumination light to a subject side according to the tilt angle of a stop. CONSTITUTION:As the stop 15 slants, the area of transmission between light transmission parts 15d pierced in light shield plates 15a and 15b decreases gradually and the quantity of light to be shielded by a light shield part 15e increases to the contrary. The quantity of stopped-down light is nearly equal between the light transmission parts 15d which face each other, so luminous flux is stopped down almost uniformly on the whole; and the intensity distribution of illumination light to the incidence end of a light guide 10 has almost no variation (as compared with when the light is not stopped down) and only the light quantity decreases, so there is no variation in light distribution characteristics of irradiation from the projection end of the light guide 10 to the subject side and spectral characteristics do not vary.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an aperture device for an endoscope light source device suitable for varying the amount of irradiation.

[Technical Background of the Invention and Problems Therewith] In recent years, endoscopes that use solid-state image sensors to display images of objects on display devices such as cathode ray tubes have been realized.

Electronic endoscopes using the solid-state imaging device mentioned above are easier to record images than those that form optical images on image guide fibers, and with the progress of highly integrated technology, It has the advantage that it can be made more and more compact.

However, when using the above-mentioned solid-state imaging device, if the amount of light incident on the photodetector on the imaging surface is too large, excessive charge leaks to the surrounding area, causing blurring and blooming on the playback screen, and There is a problem that the image cannot be reproduced faithfully and that it becomes impossible to take an image until the normal state is restored.

FIG. 7 shows an example of a conventional aperture device for controlling the intensity of illumination light on the light source device side so as to prevent the blooming phenomenon described above from occurring.

That is, the light from the discharge lamp 51 as a light source is converted into a parallel beam by the concave reflecting mirror 52, and this parallel beam is passed through the condenser lens 53.
In the optical system that collects the light and irradiates it to the input DAQ of the light guide fiber 54 as an illumination light transmission means, a circle is formed on the optical path between the condenser lens 53 and the light guide fiber 54 as shown in FIG. A diaphragm 55 in the shape of a fan-shaped notch is provided at the center of the plate and a part of the disc, and this diaphragm 55 is (
By moving (downward in FIG. 8), a part of the light beam is blocked according to the amount of movement, and the light guide fiber 5
The amount of light incident on the light guide fiber 5 is varied.
This is to adjust the amount of illumination light emitted from the other end of 4.

However, in this conventional example, when the aperture 55 is used to narrow down the light beam, the light beam is blocked from the peripheral area, so the light distribution characteristics emitted from the tip of the light guide fiber 54 toward the subject (target object) change. .

Further, since the numerical aperture of the light guide fiber 54 changes depending on the wavelength, the spectral characteristics will also change if light is blocked from the peripheral side.

Furthermore, this shape has the disadvantage that the response speed of the aperture operation is slow, making it unsuitable for automatic light control.

[Objective of the Invention] The present invention has been made in view of the above-mentioned points, and provides a light source for an endoscope that does not change the light distribution characteristics of the illumination light emitted to the subject side and has a good response speed. The purpose is to provide a squeezing device for the device.

[Summary of the Invention] A diaphragm device according to the present invention includes a light source, a lens that focuses a luminous flux from the light source onto the proximal rear end of a light guide of an endoscope, and a diaphragm that adjusts the amount of light from the light source. In the light source device for an endoscope, the diaphragm is regularly formed with a plurality of small-area light-transmitting portions having a constant transmission distance, and a plurality of light-transmitting portions that are adjacent to each other are arranged in the diaphragm. In between, there is provided a light shielding part whose light shielding area for the luminous flux changes depending on the inclination angle of the aperture, and the illumination intensity toward the subject side can be varied by the inclination angle of the aperture. It has become.

[Embodiments of the invention] Hereinafter, the present invention will be specifically described with reference to the drawings.

1 to 3 relate to a first embodiment of the present invention, FIG. 1 is an overall configuration diagram of an endoscope equipped with the first embodiment, FIG. 2 is a schematic diagram showing the operation of a light source device, FIG. 3 is a perspective view of the diaphragm device.

The endoscope 1 equipped with the first embodiment has an objective lens 3 for imaging disposed on the distal end side of the insertion section 2 having a small diameter.
A solid-state image sensor 4 such as a COD (charge coupled device) is disposed so that its imaging surface faces the image forming position. Each light-receiving element having a photoelectric conversion function is regularly arranged on the imaging surface of this solid-state image pickup device 4, and immediately before this imaging surface, a three-primary color filter 4A arranged in a mosaic pattern that transmits only light of each wavelength of the three primary colors, respectively. is attached, and the solid-state image sensor 4
depending on the clock signal applied to the red, green,
Signals corresponding to each pixel are output sequentially through a blue transmission filter, and the signals are amplified by a preamplifier (preamplifier) 5 with a low noise figure and connected to a signal cable 6.
The sample and hold circuit in the video processing section 7 separates and captures each color signal into R, G, and B.
After being amplified, the periodic signals are superimposed and input to the color monitor 8, forming an imaging means that can display a color image.

Inside the insertion section 2, there are 1. A light distribution lens 9 is disposed adjacent to the objective lens 3, and an output end of a light guide 10 made of a flexible fiber bundle is inserted into the inside of the light distribution lens 9.

The proximal rear end of the light guide 10 is detachably attached to the light source device 11 provided with the first embodiment via a connector 10A.

The light guide 10 has a concave surface (
It is made into a parallel light beam by a paraboloidal reflection M13, and is condensed by a condenser lens 14 for irradiation.

By the way, the illumination light made into a parallel beam by the above reflection [13] is
As shown in an enlarged view in FIG. 2, the amount of illumination light irradiated onto the incident end of the light guide 10 can be variably controlled by a diaphragm 15 interposed on the optical path between the reflecting mirror 13 and the condenser lens 14. .

As shown in FIG.
5b are opposed to each other via spacers 15c assembled above and below. Both light shielding plates 15a and 15b are
For example, it is a metal plate whose surface is black-treated, and the distance 1 is kept constant by the spacer 15C.

Further, a plurality of small-area light-transmitting portions 15d are regularly drilled in a checkerboard pattern in both of the light-shielding plates 15a and 15b.

Transparent portions 15d formed in both light shielding plates 15a and 15b
are opposed to each other, and a light shielding portion 15e is formed between adjacent light transmitting portions 15 of both light shielding plates 15a and 15b.

On the other hand, a shaft 16 is fixed at the center of a spacer 15G interposed above the light shielding plates 15a and 15b, and this shaft 16 is connected to a motor 17.

Therefore, when the aperture 15 is rotated and tilted from its normal state, that is, the state in which the light shielding plates 15a and 15b are orthogonal to the optical axis, as shown in FIG. 2, the light hitting the light shielding portion 15e is blocked. The amount of light traveling toward the condenser lens 14 decreases by approximately the same amount for each diaphragm unit (second
Light incident on the diaphragm 15 as shown in the matte-like shape in the figure is blocked by the light shielding portion 15e, and the amount of light passing through the diaphragm 15 is reduced).

Incidentally, the rotation angle of the aperture 15 is automatically variably adjusted based on the imaged signal.

That is, each color signal R output from the video processing section 7,
G and B are added in an adder 21 to form a brightness signal component, this brightness signal is further integrated in an integrating circuit 22 to create a dimming signal, and this dimming signal is applied to a motor drive circuit 23. It looks like this.

The adder 21 is used to maintain the color balance and produce a signal for dimming, and the integration circuit 22 is used to make the signal output from each light receiving element correspond to the light reception period. The integration circuit 22 is set to an integration time constant of about one frame or more, and the magnitude of the integrated signal level causes the rotation of the motor 17! ! 1a angle is controlled. In other words, when the level of the dimming signal passed through the integrating circuit 22 is high, the driving voltage becomes large, and for example, the angle at which the rotating shaft of the motor 17, which is biased by a coil spring, is rotated against the biasing force becomes large ( In other words, as the level of the dimming signal increases, the rotation angle of the diaphragm 15 also increases.
This is so that the amount of light passing through j is reduced.

When the diaphragm 15 is tilted, as shown in FIG. 2, the area that can pass between the light-transmitting parts 15d formed in the light-shielding plates 15a and 15b gradually decreases, and conversely, the amount of light that is blocked by the light-shielding part 15e decreases. increases. The amount of light to be narrowed down is approximately equal to each other for each transparent portion 15d facing each other, so even if the light is narrowed down, the entire light beam is narrowed down almost uniformly, and is irradiated onto the incident end of the light guide 10. There is almost no change in the bullet hole distribution of the irradiated light (from the case where the light is not narrowed down), and it is equivalent to a simple decrease in the amount of light, so the light distribution characteristics irradiated from the output end of the light guide 10 to the subject side also change. It is designed so that it does not change, and the spectral characteristics also do not change.

According to the first embodiment configured in this way, the endoscopy l11
When you bring the camera closer to a subject such as an affected area to observe the subject in detail, or move it further away to grasp its overall characteristics, the amount of light incident from the illuminated subject changes depending on the distance, and is therefore optimal. The lighting intensity changes. Solid RfII in this state! Signals corresponding to each pixel output from the element 4 are captured and displayed in color on the color monitor 8. Along with this, the separated color signals R, G, and B are added,
Furthermore, the motor 17 is driven and the rotation angle of the diaphragm 15 is varied according to the level of the dimming signal, which is integrated by the integrating circuit 24 and reflects the amount of incident light reflected from the subject during one frame period. .

For example, if the amount of incident light is too large, the level of the dimming signal will increase, and the aperture 15 will be rotated to a large angle to block light.
increases, and after one frame period, the illumination intensity is set to an appropriate level. Further, when the amount of incident light is small, the level of the dimming signal becomes small, and the diaphragm 15 is maintained in a state close to the open state (that is, a state Wg in which it is hardly rotated). In other words, not only can the blooming phenomenon be eliminated, but also the illumination intensity can be automatically adjusted to a level suitable for IT at all times.

Therefore, the operator is freed from the hassle of having to make adjustments each time according to the object distance or the reflection intensity of the object, and can concentrate on diagnosis or treatment using the treatment instrument. This allows accurate diagnosis and appropriate treatment.

According to the first embodiment, the diaphragm 15 is controlled by the motor 17.
If the diaphragm is rotated even slightly by the diaphragm, the preset can be changed immediately, and a diaphragm device with quick response can be realized. Further, even if the aperture 15 is narrowed down, the light distribution characteristics do not change from the case where it is in the open state, so it is possible to realize an illumination means for color 11 images with good color reproducibility even in any aperture state.

Moreover, FIGS. 4a and 4b show a diaphragm device according to the second embodiment, and FIG. 4a is a partial front view of the main part of the diaphragm.
Figure 4b is a side view thereof.

The aperture 30 in this embodiment is composed of a transparent plate 30c having a predetermined thickness 1, and opaque thin film sheets 30a and 30b attached to both sides of the transparent plate 30c.

In the thin film sheets 30a and 30b, light transmitting portions 30d of small area are perforated in a checkerboard pattern at the same position, and a light shielding portion 30e is formed between the light transmitting portions 30a and 30d. Note that the light shielding portion 30e may be directly formed on the surface of the transparent plate 30c by means such as printing.

When this diaphragm 30 is rotated by a predetermined angle by a motor, the light-transmitting portion 30
The light beam passing through the light e is controlled, and the effect is the same as that of the first embodiment.

5a to 5C show a diaphragm device according to the third embodiment. FIG. 5a is a perspective view of the diaphragm, FIG. 5b is a perspective view of a unit block constituting the diaphragm, and FIG. 5C is a perspective view of the diaphragm. It is a schematic diagram showing operation of a light source device.

The diaphragm 31 in this embodiment is formed by assembling a large number of rectangular parallelepiped transparent unit blocks 31G. The light shielding portion 31 is printed on the peripheral side of the unit block 31C.
e is formed. Therefore, this unit block 3
The upper and lower surface directions of 1c become the transparent portion 31d.

In the diaphragm 30 formed by joining a plurality of unit blocks 31C, the light-transmitting parts 31d adjacent to each other are connected to the light-shielding parts 3.
1e.

In the normal state where this diaphragm 31 does not rotate, the transparent part 31d
are opposed to the optical axis, and are in an open state that allows the best light to pass through.

On the other hand, as the level of the dimming signal gradually increases, the aperture 31 is rotated according to the level, and as shown in FIG. The amount of light that passes through decreases.

Moreover, FIGS. 6a and 6b show a diaphragm device according to a fourth embodiment, and FIG. 6a is a perspective view of the diaphragm, and FIG. 6b is a partially enlarged front view of FIG. 6a.

The light transmitting portion 32d of the diaphragm 32 in this embodiment is a hole formed in a honeycomb shape, and the inner circumferential surface thereof forms the light shielding portion 32.
It has become e.

When this diaphragm 32 is rotated by a predetermined angle, the light blocking portion 32e blocks the light beam from the light source 12 as in the third embodiment,
The spread decreases.

By the way, as shown in FIG. 6b, this aperture 32 is formed by bending one flat plate 32f into an uneven shape, and forming the other flat plate 32f into an uneven shape.
Q is formed by bending it in the opposite direction, and then bonding or welding the contact surfaces to each other.

As a concrete means of forming this honeycomb, first,
The flat plates 32f and 32o are stacked in a plurality of layers.

At this time, the upper surface of one flat plate 32f and the other flat plate 32Q
and the back side of the base at regular intervals with a constant width. Also, the back side of one flat plate 32f located in the middle and the other flat plate 32
The upper surface of o is joined with a constant width.

When the transparent portion 32d is made into a regular hexagon as shown in FIG. 6b, the widths of the joint portion and the non-joint portion of the hands plates 32f and 32Q are made approximately equal.

Then, the stacked flat plates 32f and 32Q are pulled in the vertical direction in the figure. Then, the non-joint part (α in Fig. 6b)
Only the portion shown by is bent to form a honeycomb.

In addition, the aperture 30 in the second to fourth embodiments described above
The configuration other than 32 is the same as that of the first embodiment shown in FIG.

Furthermore, the present invention is not limited to an aperture device in which the aperture is rotationally driven by a motor in response to a dimming signal, but also includes a device in which the aperture can be operated manually.

[Effects of the Invention] As described above, according to the present invention, the amount of passing light can be adjusted uniformly by changing the inclination angle of the aperture, and the light distribution can be maintained even if the amount of illumination light irradiated from the output end of the light guide to the subject is varied. Characteristics do not change.

Moreover, illumination can be achieved without changing the color tone of the captured image of the subject due to the bite R and without causing any local unevenness, making it easier to make accurate diagnoses. In addition, it has good responsiveness and is suitable for an aperture device of an automatic light control means.

[Brief explanation of drawings]

1 to 3 relate to a first embodiment of the present invention, FIG. 1 is an overall configuration diagram of an endoscope equipped with the first embodiment, FIG. 2 is a schematic diagram showing the operation of a light source device, Figure 3 is a perspective view of the diaphragm device;
4a and 4b relate to the second embodiment of the present invention, FIG. 4a is a front view of the main part of the diaphragm, FIG. 4b is a side view thereof, and FIGS. 5a to 5C are the second embodiment of the present invention. 5a is a perspective view of the aperture, FIG. 5b is a perspective view of a unit block constituting the aperture, FIG. 5C is a schematic diagram showing the operation of the light source device, and FIGS. 6a and 6b are According to the fourth embodiment of the present invention, FIG. 6a is a perspective view of a diaphragm, FIG. 6b is a partially enlarged view of FIG. 6a, and FIG. 7 is a schematic diagram showing the operation of a light source device having a conventional diaphragm device. FIG. 8 is a front view showing the shape of the conventional aperture used in FIG. 1... Family celebration 1t 10... Light guide 11.
...Light source device 12...Light source 14...Lens
15.30~32...Aperture 15d, 30d, 31d
, 32d...openings 15e, 30e, 31e, 32e
...Light shielding part 1...Transmission distance, Patent attorney Susumu Ito □. Figure 1 Figure 2 Figure 6o Figure 6b Figure 7

Claims (1)

[Claims] In a light source device for an endoscope, the light source device is provided with a light source, a lens that focuses the light flux from the light source onto the proximal rear end of a light guide of the endoscope, and a diaphragm that adjusts the amount of light from the light source. , a plurality of small-area transparent parts having a constant transmission distance are regularly formed in the diaphragm, and a plurality of light-transmitting parts of a small area having a constant transmission distance are arranged between adjacent transparent parts by adjusting the inclination angle of the diaphragm. 1. A diaphragm device for an endoscope light source device, comprising a light shielding portion whose light shielding area for a light beam changes.