JPS6141428A - Iris apparatus of light source apparatus for endoscope - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a diaphragm device for an endoscope light source device suitable for varying the illumination O4 light presentation to a subject.

"Technical use of the invention and its problems" In recent years, endoscopes that use solid-state focusing elements to display images of objects on display devices such as cathode ray tubes have been realized. It is in.

An electronic endoscope using a solid-state imaging element described above is easier to record an image (α;) than one that forms an optical image on an image guide fiber, and is With the progress of integration technology, there is now an advantage that it can be made smaller and smaller.

However, when using the above-mentioned solid-state image element, if the amount of light incident on the light receiving element on the imaging surface is too large, excessive charge leaks to the surrounding area, causing blurring and blooming phenomenon on the playback screen, and that part is It becomes impossible to faithfully reproduce the file, and it takes 1 file until the normal state is restored.
There is a problem that it becomes impossible to image.

As a conventional example of a diaphragm device for controlling the intensity of illumination light on the light source device side so as to prevent the above-mentioned blooming phenomenon from occurring, there is one shown in FIG.

That is, light from a discharge lamp 51 as a light source is reflected by a concave reflecting mirror 52 to form a substantially parallel light beam, and a condenser lens 53 irradiates this parallel light beam onto the input end of a light guide fiber 54 as an illumination light transmission means. In the optical system, as shown in FIG. 11, on the optical path between the condensing lens 53 and the light guide fiber 54, there is a central part of a disk and a fan-shaped notch formed by cutting out a part of the disk. 55 is arranged, and this aperture 55 is (
By moving (downward in FIG. 11), a part of the light beam is blocked depending on the amount of movement, thereby varying the amount of light incident on the light guide fiber 571, and the light is emitted from the other end of the light guide fiber 54. This is to adjust the amount of illumination light.

However, in this conventional example, when the aperture 55 is used to narrow down the light beam, the light beam is blocked from the periphery, so that the light beam exits from the tip of the light guide fiber 54 toward the subject (object).
As the light distribution angle f1 changes, the spectral property ↑1 also changes. Furthermore, this structure has the disadvantage that the response speed of the aperture operation is slow, making it unsuitable for automatic light control.

[Object of the Invention] The present invention has been made in view of the above-mentioned point 1, and provides a method that does not change the light distribution characteristics and spectral characteristics of the illumination light emitted to the subject side, and also has a good response speed. An object of the present invention is to provide a diaphragm device for a light source device for an endoscope.

[Summary of the Invention] The present invention provides a plurality of sets of fan-shaped aperture blades made of a foldable light-shielding member housed in a hollow part of an annular frame, and a method for mounting the aperture blades [by rotating the puta frame]. This constitutes an aperture device that can vary the amount of light passing through by changing the amount of folding of the aperture blades.

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

Figures 1 to 6 relate to the first embodiment of the present invention.
The figure shows an endoscope equipped with the first embodiment, FIG. 2 shows the diaphragm device of the first embodiment, and FIG. 3 shows a side view of a pair of diaphragm blades forming the diaphragm. Figure 4 shows the shape of the diaphragm when viewed from the optical axis direction with different aperture amounts, Figure 5 shows the state of a pair of diaphragm blades in each state of Figure 4, and Figure 6 4 is an enlarged side view of each state shown in FIG.

An endoscope 1 equipped with the first embodiment has an objective lens 3 for imaging disposed on the distal end side of an elongated insertion section 2.
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 arranged correctly on the imaging surface of the solid-state image sensor 4, and three
Three primary color filters 4A are installed in a mosaic arrangement that transmit only light of each wavelength of the primary colors, respectively.
Signals corresponding to each pixel are output sequentially through green and blue transmission filters, and the signals are amplified by a preamplifier (preamplifier) 5 with a low noise figure, and sent to the video via a signal cable 6. The sample and hold circuit in the processing section 7 separates and captures each color signal into R, G, and B. After amplifying each color signal, a synchronization signal is superimposed and input to the monitor color television 8 as a color image. An image carrying means is formed to enable display.

A light distribution lens 9 is disposed in the insertion section 2 so as to be adjacent to the objective lens 3, and a light guide 10 constituted by a flexible fiber bundle with its output end facing inside the light distribution lens 9. is inserted.

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

At the rear end of the light guide 10, which is the input end of the illumination light, the illumination light from the illumination lamp 12, such as a discharge lamp, is reflected by a concave (paraboloid) shaped reflecting mirror 13 and converted into a substantially parallel light beam.
The light is condensed by a condenser lens 14 and irradiated.

By the way, the illumination light made into a substantially parallel beam by the reflecting mirror 13 is irradiated onto the incident end of the light guide 10 by an aperture 15 provided between the reflecting mirror 13 and the condenser lens 14, for example, at the pupil position of the condenser lens 14. A diaphragm device is configured that can variably control the amount of light. This light guide 10
The illumination light flux incident on the rear end of the light guide 10
It passes through the core of each fiber constituting the fiber, and is transmitted to the tip side while being completely bent at the boundary with the cladding layer on the outer periphery of the core. It is designed to be emitted with

As shown in FIG. 2, the diaphragm 15 has a pair of fan-shaped diaphragm blades 17 in the hollow parts of two annular frames 16A and 16B.
For example, A and 17B are the 4-set number I-Rof.

Each pair of aperture blades 17A, 17B is formed of a light-shielding member such as metal, and the adjacent side ends are hinges 18, etc., as shown in FIG. The other side end of one aperture blade 17A is rotatably fixed to one frame 16A with a pin 19 or the like.
The other side end of the other aperture blade 17B is rotatably fixed to the other frame 16B with a pin 19 or the like. Therefore, it may be placed on the outer periphery of one frame 16Δ, either over the entire periphery or partially. ) The rotor side is formed with a meshing portion 20 and is meshed with a gear 22 mounted on the rotating shaft of the Tanabata 21 so that it can be rotated in the J direction shown by the arrow in FIG. On the other hand, the other frame 16B is a J: sea urchin frame that serves as a stator side frame that is held in a fixed state. Furthermore, -1-
The rotor side frame 16A is connected to the stator side frame 1 at the center of the ring.
It is rotatably (μ) supported by 6B. Also, the axis at the center of rotation is located at the central axis of the illumination light beam, and the optical axis 1-.

The frame 16A on the rotor side is the gear 2 attached to the motor 21.
As shown in FIG. lJ: The amount of aperture can be variably adjusted from the open state where the weight of passing light is at its maximum to the continuous light state where the weight of passing light is approximately zero. In other words, the normal state is as shown in Figure 4(a).
As shown in the figure, each pair of aperture blades 17A and 17B are folded over each other and are in an open state protruding perpendicularly to the surface of the ring.
The light passing through the aperture 15 in this state has the maximum amount of illumination light.

When the rotor-side frame 16A is rotated from this open state, the angle formed by each pair of aperture blades 17A and 17B (opening angle (indicated by the symbol α in FIG. 3) becomes larger, and the light hitting each of the opened aperture blades 17A, 17B is blocked, and the amount of illumination light irradiated onto the light guide 10 is reduced.

After being rotated further than the state shown in FIG. 4(b), each
When the aperture angle of the pair of aperture blades 17A, 17B reaches approximately 180°, light is almost completely blocked as shown in FIG. 4(C).

Figure 5 (a), (b), (c) and Figure 6 (a), (b)
), (C) are 1 in Figure 4 (a), (b), and (c).
The states of the pair of aperture blades 17A and 17B are shown in a perspective view and from the side, respectively.

Incidentally, when each pair of aperture blades 17A, 17B is opened at an appropriate angle, a portion G through which light passes is generated on the outer periphery of each aperture blade 17A, 17B in FIG. 4(b). If used as an aperture, no problem will occur.

By the way, the motor 21 that rotates the second aperture 15 in the negative direction is controlled based on a dimming signal that automatically sets the illumination light amount to an appropriate amount.

That is, each color signal R output from the video processing unit 7,
G and B are added by a filter 25 to form a brightness signal component, and this brightness signal component is roughly integrated by an integrating circuit 26 to create a dimming signal, which is sent to a motor drive circuit 27. J applied to: sea urchin.

- The tube tube 25 is used to maintain color balance and produce a dimming signal, and the integration circuit 26 is used to match the light reception period of the signal output from each light receiving element. The integration circuit 26 is set to an integration time constant equal to or more than one frame per frame, and the rotational drive angle of the motor 21 is controlled by the magnitude of the integrated signal level. In other words, when the level of the dimming signal passed through the integration circuit 26 is large, the driving voltage becomes large, and for example, the angle at which the rotating shaft of the motor 21, which is biased by a coil spring (not shown), is rotated against the biasing force increases. It's meant to grow bigger.

In other words, as the level of the dimming signal increases, the rotation angle also increases, so that the amount of light passing through the aperture 15 is reduced.

The diaphragm 15 is narrowed by the same amount by each pair of diaphragm blades 17A and 17B, and when the diaphragm 15 is narrowed down, the center side and the outer circumference side of the diaphragm 15 are narrowed down in the shape of a fan area. This is to prevent angular dependence of the illumination light irradiated onto the incident end of the light guide 100. Therefore, the light distribution characteristic of light irradiated from the output end of the light guide 10 to the subject side does not change depending on the aperture amount, and only the amount of illumination light can be uniformly varied (over the illumination range). Furthermore, the aperture (passage) area and the light-shielding area are varied in a fan-like manner, so that the spectral characteristics are not easily blurred.

According to the first embodiment configured in this way, when the endoscope 1 is brought close to a subject such as an affected area to closely observe the subject, or when it is moved away to grasp the overall characteristics, The amount of light incident from the illuminated subject changes according to the distance m1ll, and therefore the optimum illumination intensity changes. Signals corresponding to each pixel output from the solid-state image sensor 4 in this state are taken into the video processing section 7 and displayed in color on the color television 8. The separated color signals R, G, and B are added by an adder 25, and then integrated by an integrating circuit 26 to reflect the amount of incident light that is reflected by the object and incident during a 1.1 frame period. Depending on the level of the dimming signal, the rotation angle of the motor 21 and the aperture 15 connected to the motor 21 is varied. For example, if the amount of light required is too large, the level of the dimming signal will increase, the aperture 15 will be rotated by a large angle, and the amount of light blocked will increase.
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 an open state (that is, a state in which it is hardly rotated). In other words, the illumination m is always automatically adjusted to be suitable for imaging.

Therefore, the operator is freed from the hassle of having to adjust the light each time depending on 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.

Further, according to the first embodiment, when the diaphragm 15 is rotated even slightly by the motor 21, the amount of light can be immediately varied, and a diaphragm device with quick response can be realized. Further, even if the aperture 15 is stopped down, the light distribution characteristics and spectral characteristics do not change from those in the open state, so it is possible to realize an illumination means for color imaging with good color reproducibility even in any aperture state.

Therefore, even in the case of @imaging means using the solid-state image sensor 4, color image transfer and color display without color shift can be achieved.

The aperture device described above is used for a light source device for conveying color images using a white light source, but the aperture device of the present invention can also be applied to a light source device forming a color plane sequential type illumination means. For example, FIG. 7 shows an embodiment in which the aperture device of the second embodiment is applied to an endoscope 31 having a color plane sequential type light source device.

In this endoscope 31, a monochrome solid-state image carrier 4 without a color filter such as a mosaic arrangement is used, and in a light source device 32, a concave reflecting mirror 1 is used.
The aperture 33 in the second embodiment is disposed on the optical path that is made into a parallel beam by the diaphragm 33 shown in the second embodiment. This comparison 33 is the 8th
As shown in the figure, each pair of aperture blades 17A, 17B is flexible without using a hinge 18, and one heat-resistant glass fiber plastic member 24 is rotatable using an adhesive or the like. The structure is similar to that of the diaphragm 15 in the first embodiment, except that the diaphragm 15 is foldably connected.

The aperture 33 constitutes an aperture device that is rotationally driven by the motor 21 and can variably adjust the aperture depth.

The luminous flux narrowed down by the aperture 33 is]
The light is once condensed by the I-lens 14, expanded again by the concave lens 36 to form a parallel light beam with a small diameter, passed through the rotating filter 37, and further condensed by the condenser lens 38 to irradiate the incident end of the light guide 10. I have to.

The rotary filter 37 has a fan-shaped red transmitting filter, a green transmitting filter, and a blue transmitting filter arranged around a rotation center, and is rotationally driven by a motor 39.

The motor 39 is rotated by a pulse signal supplied from a motor drive circuit 40 so that each color transmission filter is sequentially placed on the optical path.

Then, the subject is illuminated through each color transmission filter,
The object illuminated in each color is received by each light receiving element of the solid-state image sensor 4, and is taken into the video processing section 7' by application of a readout signal. The signal taken into the video processing unit 7- is converted into 0 and then sequentially written into a color frame memory (not shown) for recording each color by a switching circuit (not shown). The signal data written in each of the three color frame memories are read out simultaneously, each is DA-converted into an analog signal, and is amplified by a color amplification circuit (not shown) to produce each color signal R, G.

B, input to the color preview 8, and displayed as a color image.

Note that, unlike the optical system shown in FIG. 1, in the light source device 32, by using a concave lens 36, the area of the parallel light beam can be reduced, and a rotating filter 37 with a small area can be used.

This rotary filter 37 can be constructed using an interference filter with good heat resistance.

Other configurations are shown in Figure 1? It has the same configuration as fl mirror 1. According to this endoscope 31, in addition to having substantially the same effects as the endoscope 1 provided with the first embodiment, it is also possible to obtain a color image with high resolution.

Note that the present invention is not limited to an aperture device that forms a dimming signal and controls the amount of rotational drive of the motor 21 based on this dimming signal to vary the aperture amount of the aperture 15.33.
33, that is, a diaphragm device consisting only of the diaphragm 15 and 33 (in the case of manual operation, it is desirable to provide a knob for rotational operation).

In each of the above embodiments, a pair of aperture blades 17A is used.

Although four diaphragms 17B are provided to form the aperture 15.33, the present invention is not limited to this, and two, three, or five or more may be provided. In general, the more light the more uniformly irradiated each fiber of the light guide 10 can be, and the less variation in light distribution characteristics can be achieved.

The above-mentioned diaphragm 15.33 is constructed using a plurality of pairs of diaphragm blades 17A and 17B, but the present invention also includes a fan-shaped blade (fan-shaped light shielding part) that does not move together with these blades. belong to

In addition, the above-mentioned aperture 15.33 is shown in Fig. 6 (C) in the light shielding state.
As shown in the figure, it opens in a straight line, but the amount of opening is made smaller than this (so that the opening angle α is slightly larger than 180° so that light can be blocked), and then the opening angle α is smoothly reduced to a smaller state. It can also be made easier to migrate.

Furthermore, the pair of aperture blades constituting the aperture 15.33 is not limited to fan-like flat blades, but may be curved aperture blades 17A' and 17B as shown in FIG. 9, which shows a part of the aperture of the third embodiment. = But it's okay. By forming the curved surface in this way, the frame 16A
The rotation angle and the amount of aperture can be variably adjusted.

Further, the annular frames 16A and 16B are not limited to being provided so as to be almost in contact with the annular ring, but may be provided at a distance. Also, one pair of aperture blades 17A and 17B.

The position where 17A' and 17B= are pivoted is not limited to being pivoted at (the outer circumferential side of) the side end opposite to the side end connected by the hinge 18, etc., but may also be in the middle (the outer circumferential side of). .

Further, the annular frames 16A and 16B are not limited to one that can be rotated, and the other can also be configured to be able to rotate simultaneously in opposite directions using a gear or the like. Further, each pair of aperture blades may be rotatably connected by other methods.

[Effects of the Invention] As described above, according to the present invention, a plurality of pairs of foldable fan-shaped blades are provided in the hollow part of the annular frame using a light-shielding member, and the frame can be rotated. By doing so, the aperture angle of each pair of blades changes and the shading area can be varied in a fan shape, so even if the aperture amount is changed, the illumination light intensity can be adjusted without changing the light distribution characteristics and spectral characteristics. can be adjusted. In addition, the aperture amount can be reliably and variably adjusted with rotation, making it suitable for an aperture device for an automatic light control device, etc.
The response is also fast.

[Brief explanation of the drawing]

Figures 1 to 6 relate to the first embodiment of the present invention.
The figure is a configuration diagram showing an endoscope equipped with the first embodiment, FIG. 2 is a perspective view showing the aperture device portion of the first embodiment, and FIG. 3 is an enlarged view of a pair of aperture blades in the aperture. Fig. 4 is a front view showing various states in which the aperture amount is different, and Fig. 5 is a side view showing each state in which the aperture aperture amount is different in Fig. 4.
A perspective view showing each state of the pair of aperture blades, Fig. 6 is a side view showing an enlarged part of each state shown in Fig. 4 (), and Fig. 7 is an internal view of the second embodiment. Configuration diagram showing the mirror, Figure 8 is the second
FIG. 9 is a side view showing a part of the diaphragm in the third embodiment of the present invention; FIG.
FIG. 0 is an explanatory diagram showing an optical system of a conventional light source device, and FIG. 11 is a front view showing a conventional aperture. 1.31...Endoscope 2...Insertion section 4...Solid image carrier 7.7'...Video processing section 10...Light guide 11.32...Light source device 12...・Lighting lamp 15.33...Aperture 16
A, 16B...Frame 17A, 17B, 17/M, 17B-...Aperture blade 18...Hinge 21...Motor 22...
・Gear 25...Clincer 26...Integrator circuit 27...Motor drive circuit 34...Plastic member 37...Rotary filter

Claims (1)

[Claims] Illumination light is emitted toward the subject from the distal end of the light guide that is inserted into the insertion section of the endoscope, and the rear end of the light guide on the proximal side is attached to the light source for illuminating the light source in the endoscope light source device. In the aperture device of an endoscope light source device, which makes it possible to adjust the illumination intensity irradiated to the subject to an appropriate amount by narrowing down the luminous flux and irradiating it to the rear end of the light guide, one side is rotated around the central axis, and the other is Two annular frames that are relatively rotatable are provided to face each other, and a pair of fan-shaped frames made of a light-shielding member are provided in a hollow portion inside the annular frame through which light can pass. Rotation is possible by storing a plurality of pairs of blades and pivoting the other side ends of each pair of blades, which are foldably connected to each other at adjacent side ends, to each of the annular frames. A diaphragm device for an endoscope light source device, characterized in that the amount of light passing through the hollow portion can be variably controlled in accordance with the amount of rotation of the frame.