JPS6141430A - 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 an aperture device for an endoscope light source device suitable for varying the irradiation destination on a subject.

[Technical background of the invention and its problems] In recent years, endoscopes that use solid-state image sensors to display images of objects on display devices such as cathode ray tubes are being put into practical use.

Electronic endoscopes using the solid-state imaging device described above are easier to record images than those that form optical images on image guide fibers, and they are also capable of recording images with the advancement of highly integrated technology. , which has the advantage of being able to be made even smaller in the future.

However, when using the above-mentioned solid-state image sensor, if the tip of the light-receiving element on the imaging surface is too large, excessive charge will leak to the surrounding area, causing blurring and blooming on the playback screen, and that part will be removed from the image. There is a problem that it becomes impossible to faithfully reproduce the 1n1 image, and it also becomes impossible to reproduce the 1n1 image until the normal state is restored.

There is a 4T aperture device as shown in FIG. 7 as a conventional example of an aperture 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.

That is, the light from the discharge lamp 51 as a light source is reflected by the four opposite faces 52 of a paraboloid to form a substantially parallel light beam, and this parallel light beam is passed through the condenser lens 53 to the light I to the guide fiber as the illumination light transmission means. In the optical system that irradiates the incident end of 540, the central part of the light-shielding disk and a part of the disk are arranged in a fan shape on the optical path between the condenser lens 53, the light t, and the guide fiber 54, as shown in FIG. By moving or rotating the diaphragm 55 (downward in FIG. 8), a part of the light beam is blocked and directed to the light guide fiber 54 according to the amount of movement. The amount of illumination light emitted from the other end of the light guide fiber 54 is adjusted by varying the incident photons.

However, in this conventional example, as the light is narrowed down by the aperture 55, the light beam is continuously emitted from the periphery. Light properties change.

Furthermore, since the numerical apertures N and A of the light guide fiber 511 depend on the wavelength, when light is continuously emitted from the peripheral side, the spectral characteristics also change. In addition, this shape has the disadvantage that the response speed of the diaphragm operation is almost the same, making it unsuitable for automatic light control.

[Purpose of the Invention] The present invention has been made in view of the above-mentioned points, and it is possible to achieve internal vision that has good response speed without changing the light distribution characteristics of the Q1 illumination light emitted to the subject side. An object of the present invention is to provide a diaphragm device for a mirror light source device.

[Summary of the Invention] The present invention consists of a pair of annular frames arranged so that their centers coincide with the optical axis of the illumination light beam, and formed of a light-shielding ladle member, which can be opened and closed over a wide angle around the optical axis. By attaching each side end of the bellows-shaped collapsible aperture blades Gt and rotating one of the annular frames with a morph, etc., the light flux passing through the inside of the annular ring is blocked in a fan shape and guided to lie 1. The intensity 1σ of the illumination light irradiated from the output end to the subject side can be varied without changing the light distribution t'l.

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

1 to 5 relate to one embodiment of the present invention, FIG. 1 shows an optical system of a color plane sequential illumination type light source device equipped with the first embodiment, and FIG. Setting (-1 shows the endoscope, Figure 3 shows the rotational force) - Filter, Figure 4 shows the 1
The aperture device of the embodiment is shown, and FIG. 5 schematically shows two states in which the amount of aperture applied to the aperture is different.

As shown in FIG. 2, the endoscope 1 is 11 hours different from the first embodiment.
An objective lens 3 for imaging is disposed on the distal end side of the elongated insertion section 2, and a solid-state imaging device such as a COD (charge-coupled device) is arranged so that the image carrying surface of the objective lens 30 faces the stomach in the prone position. 4 is installed. In the flit image of the solid-state image element 4, there are a large number of light-receiving elements that cover the surface electric conversion function, arranged in a regular i[shifted arrangement].Therefore, each light-receiving element separates into pixels and receives light. The electrical signals corresponding to the photoelectrically converted pixels are sequentially read out according to a clock signal (not shown), and the read signals are amplified by a preamplifier (preamplifier) 5 with a low noise figure. It is designed to be taken into a video processing section 7 via a signal cable 6.This video processing section 7 converts the taken signal from analog to digital.
Images of each color under color-plane sequential illumination, which will be described later, are switched by a multiplexer and written into dedicated frame memories. The written signals (data) are simultaneously read out in the read mode, converted into analog color signals R, G, and B by a D/Δ converter, and then amplified before being converted into horizontal and vertical synchronizing signals (not shown). An imaging means is configured which is added and inputted to the monitor color television 8 so that it can be displayed as a color image.

A light distribution lens 9 is disposed in the insertion portion 2 so as to be adjacent to the objective lens 3, and a light guide 10 is inserted through the light distribution lens 9 so that its output end faces inside the light distribution lens 9.

In one embodiment, the proximal rear end of the guide 10 to the lie 1 is set (
``The light source device 11 can be removably attached to the light source device 11.

In the light source device 11, as shown in an enlarged view in FIG. 1, a discharge lamp 12 for illumination emits 1! The illumination light is reflected by the concave (parabolic) reflecting surface 13 and becomes almost a parallel light beam, and this parallel light beam is passed through the first convex lens 14 for condensing. The light is focused by -1- On the optical path of the parallel light beam, that is, between the discharge lamp 12 and the convex lens 14, the diaphragm 15 constituting one embodiment is disposed, for example, at the pupil position of the convex lens 14, and the amount of passing light is It is being narrowed down. This diaphragm 15 is driven by a motor 17 via a gear 16, thereby forming an diaphragm device that can vary the amount of diaphragm.

The light flux that passes through the aperture 15 and is condensed by the first convex lens 14 is condensed at approximately one point on the optical axis after advancing by the focal length of the convex lens 171. The convex lens 18 converts the parallel light beam into a parallel light beam with a diameter smaller than the parallel light beam [,1. The light is focused by a convex lens 20 and irradiated onto a guide 10, which has a rear end surface serving as an entrance end near the focal point position. The illumination light irradiated at a predetermined angle is transmitted through the core of each optical fiber forming the light guide 10, and is not totally reflected at the boundary of the cladding layer on the outer periphery. The light is transmitted to the object (subject) side either directly from the tip of the light guide 10 or after being further diffused by the light distribution lens 9, and the light is expanded and emitted. The range that can be imaged by the objective lens 3 can be approximately uniformly illuminated by the illumination light.

The rotating filter 19 is disposed, for example, in the pupil device of the convex lens 20, and as shown in FIG.

A red transmission filter 19R that transmits only light of each wavelength of blue,
The green transmission filter 19G and the blue transmission filter 19B are each formed in a fan shape of 120 degrees, and one J is provided on the t-shape 21 as a rotational driving means (four filters are installed so as to be rotationally driven).

Note that the motor 21 is driven by electric power supplied from a motor drive circuit 22.

This motor 21 is, for example, a pulse motor that rotates by a predetermined angle in response to input pulses, and each color transmission filter 19R, 19G, 19B is connected to the convex lens 18 and 2.
0, the driving pulse is not supplied to the (pulse) motor 21 for a short predetermined period of time, and after the predetermined illumination time, the driving pulse is supplied and the next color filter is immediately moved to the convex lens. It should be on the optical path between 18 and 20. In this way, a color plane sequential illumination means is formed which sequentially illuminates the subject with each color through the transmission filters 19R, 19G, and 19B of the three primary colors.

The driving pulses for the motor driving circuit 22 are output based on a control signal used for switching a multiplexer (not shown) in the video processing unit 7.

Alternatively, the multiplexer v can be switched in synchronization with the driving pulse.

Each transmission filter 19R forming the rotary filter 19
, 19G, 19B, for example, on the surface of the glass substrate,
Interference filters are created by stacking dielectric transparent thin films in multiple layers depending on the purpose of use, such as by vacuum deposition, and making use of the light interference caused by these thin films to allow only light of a specific wavelength to pass through. (vapor-deposited film filter) is used. Since this interference filter has good heat resistance, the above-mentioned light source device 1
It can also be used in areas where the energy density of light is relatively high, such as the focused parallel beam part in 1.

By the way, in the endoscope 1 equipped with the first embodiment, the illumination intensity may be too high (strong) when the subject is too close and the illumination intensity is too high, or when the subject has a highlighted part with high reflection intensity. Automatic light control means is provided to prevent blooming, the overall appearance of whitishness, and insufficient contrast. However, the diaphragm device of one embodiment is controlled based on the light control signal of the automatic light control means.

Namely, 1) the color signal R output from the video processor 7;
G and B are added by an adder 23 to obtain a luminance signal component, and this luminance signal component is integrated by a right-swing integration circuit 24 with a time constant of about one frame period, and this is used as a dimming signal. A motor drive circuit 2 in which the dimming signal is a drive source for the motor 17
It is applied to the control end of 5.

The motor drive circuit 25 may be configured using a power amplifier circuit or the like that increases the amount of rotation of the motor 17 by greatly varying its output current or output voltage as the bias level applied to the control terminal increases. can.

By the way, the aperture device of the first embodiment is composed of a sea urchin aperture 15 and its driving means, which are shown enlarged in FIG. 4.

That is, two annular frames 31 and 32 are arranged facing each other so that their centers coincide, and one side end is fixed to one of the annular frames 31 to a radial fixing piece 33 of 11 girders.
A foldable piece 61a is connected to the other annular frame 32 via a pin 35 to a movable piece 34 whose other side end is fixed.
The diaphragm 15 is composed of bellows-shaped diaphragm blades 36 and the like. Further, a meshing portion 37 formed on the outer peripheral surface of the annular frame 32
and a motor 17 which rotationally drives the annular frame 32 via a gear 16, forming a driving means for varying the aperture. In FIG. 4, the two annular frames 31 and 32 are shown enlarged considerably.

The aperture blades 36 are made of a light-shielding member.

For example, it is made of a heat-resistant member such as gaff fiber mixed with carbon.

The diaphragm 15 is arranged so that the centers of both annular frames 31 and 32 are on the optical axis of the illumination light beam, and when the rotation angle of the diaphragm 15 is 00 when it is rotationally driven by the aerator 17, the diaphragm blades 36 are almost When the aperture blades 36 are completely folded, the maximum amount of light passes through the open state.As the rotation angle increases, the angle at which the aperture blades 36 open in a fan shape increases, and this open portion blocks light and reduces the amount of light that passes through the inside of the annular ring. It can be gradually reduced. For example, FIG. 5(a) schematically shows a state in which the angle of the diaphragm blades 36 is small and the amount of light passing through is relatively large, and FIG. Indicates a relatively small state. Thus, when the annular frame 32 is rotated by 180 degrees, it can be completely shielded from light.

- The comparison device of the first embodiment has good responsiveness because the amount of passing light can be varied almost linearly with the rotation of the motor 17. Also, when the aperture amount is varied,
Since the passing light changes in a fan shape, it does not depend on the aperture amount, and the intensity can be adjusted without changing the light distribution characteristics and spectral characteristics of the illumination light emitted from the output ends of the lights 1 to guides 10 to the subject side. Only the (light amount) changes. Therefore, even if the illumination and imaging are carried out sequentially in color planes, the color tone of the object does not change (partially, etc.) depending on the aperture, and color display can be performed with faithful color tone.

The operation of the endoscope 1 having one embodiment configured as described above will be described below. When the distal end of the insertion section 2 of the endoscope 1 is brought close to a subject such as an affected area (for magnified observation, or when moved away to grasp the overall characteristics), the illumination will vary depending on the distance. The amount of light incident from the subject changes, and therefore the optimal illumination intensity changes.In this state, the signal corresponding to each pixel output from the solid-state image sensor 4 is captured by the video processing unit 7, and one signal is generated for each color. Each frame is written to each frame memory.When illumination and imaging are performed in three different colors, the data in each color frame memory is simultaneously read out, D/A converted, and converted into a color signal. R, G, (further amplified),
The image is displayed as a color image on the color television 8, and is also input to the adder 23 forming an automatic light control means.

This adder 23 converts the luminance signal into a luminance signal, and the integrator circuit 24
The output of the motor drive circuit 25 is controlled by the level of this dimming signal. In other words,
If the lighting intensity is too high and the level of the dimming signal is large,
The output of the motor drive circuit 25 is obscured, and conversely, when the illumination intensity is too low, the level of the dimming signal becomes small, and this dimming signal controls the 1u rotation of the motor 17, and the rotation amount of the motor 17 is The aperture blade 3 of the aperture 15 is proportional to
The amount of light shielding (or the amount of aperture) of No. 6 is variable.

Therefore, the illumination intensity irradiated to the subject side with the aperture suspended is maintained for the next (color) one frame period (for each color frame, three frame periods). When one frame is successively imaged under this illumination light whose intensity has been changed to the appropriate intensity side, the illumination intensity is sufficiently close to the appropriate value. Furthermore, since the aperture space is blocked in a fan-like manner, the light distribution characteristics of the illumination light irradiated from the output end of the light guide 10 to the subject side do not change. Therefore, the displayed color image will have appropriate colors and tones.

Therefore, the operator does not have to worry about adjusting the illumination bullet holes, and can concentrate on diagnosis or treatment.

Further, in the light source device 11, the first convex lens 14
The second convex lens 18 condenses the light, converts it into a parallel light beam with a small area, and passes it through the rotating filter 19 formed of a heat-resistant interference filter. A small-sized rotary filter 19 can be used, and the torque for rotationally driving the rotary filter 19 can be small, and the motor 21 with a small torque can be used to drive the rotary filter 19 sufficiently. Therefore, light source device 1
1 can be made smaller and the cost can also be reduced. In addition, since it is a color plane sequential illumination method, it is possible to form an illumination means for clear color imaging and display of minute parts without reducing the resolution, which is very useful for diagnosis.

Although the above-described first embodiment is used for a light source device 11 of a color plane sequential illumination type, the present invention can also be applied to a light source device for white illumination.

FIG. 6 shows an endoscope 41 having a light source device for white illumination.

The endoscope 41 is equipped with a light source device 42 for white illumination. Further, for color imaging, color filters 4A, such as a mosaic arrangement, are arranged in front of the solid-state image sensor 4.

The light source device 42 has a diaphragm 15 disposed on the optical path between the discharge lamp 12 and the convex lens 14 for condensing light, similar to that shown in FIG. The light beam condensed by this convex lens 14 is irradiated onto the light guide 10 whose incident end is disposed near the focal point position.

This light guide 10 people! 1l) The white illumination light irradiated to the l end is emitted from the output end to the subject side via the light distribution lens 9. The subject illuminated with this white illumination light passes through the color filter 4A, is received by each light receiving element as pixels of each color, is sequentially read out by application of a readout signal, and is taken into the video processing section 7''. The signal taken into this video processing section 7' is separated into pixel signals of each color by a sample and hold circuit, for example, and output as color signals R, G, and B. After being amplified, the signals are sent to a color television monitor. It is designed to be output to the side.

The other parts have substantially the same configuration as the endoscope 1 described above.

The operation and effect of this endoscope 41 are substantially the same as those of the endoscope 1 described above. Although the aforementioned endoscope 1 is superior in terms of resolution, this endoscope 41 is better able to capture a color image of a fast-moving subject without causing color shift.

In the present invention, as shown in FIG. 4, the fixed piece 33 and the movable piece 34 are not necessarily required. It may be fixed. Also, the part other than the center of the other side edge (
It may be fixed to the other annular frame 32 via a pin 35 attached to the outer circumference (preferably on the side closer to the outer periphery). Further, the annular frames 31 and 32 are provided close to each other, and the other side end of the aperture blade 36 is directly connected to the other annular frame 32 without using the pin 35.
It can also be fixed to

Note that the diaphragm blades 36 are not limited to those that have the ability to be folded by bending a light-shielding disc in the radial direction to form fan-shaped pieces each having a small apex angle.
For example, a notch for connection may be provided on one side end of the fan-shaped pieces adjacent to each other, and an engagement piece that engages with this notch may be provided on the other side to form the aperture blades 36. You can also do it.

Note that the aperture blades 36 are not limited to those that open and close over a range of 0° to 180°, but may be sufficient to open and close over a wide angle.

Further, the annular frames 31 and 32 constituting the diaphragm are not limited to those that can be rotated only on one side, but can also be used so that they can be rotated in opposite directions.

Furthermore, by providing a plurality of the apertures 15 and correspondingly providing a plurality of gears 16 of the motor 17, it is possible to greatly vary the previous speed within a small rotation range. In this case, the listening angle of the aperture blades 36 may be small. Further, even if the number of aperture blades 36 is increased, the same effect can be omitted.

Note that the diaphragm device of the present invention is not limited to one having a driving means such as the motor 17, but also includes one that can be driven manually (that is, a diaphragm device constituted by the diaphragm 15).

[Effects of the Invention] As described above, according to the present invention, an aperture device is formed in which the amount of light passing through can be varied by making the degree of contact of the foldable aperture blades variable in a fan-like manner as well as rotation. The intensity of the illumination light irradiated onto the subject side can be changed without changing the light distribution characteristics and spectral characteristics. In addition, since the aperture suspension can be varied linearly with rotation,
The response is quick and by using it as an automatic light control means, it is possible to quickly set an appropriate aperture amount or illumination intensity. In addition, since the lighting intensity can be varied without changing the light distribution characteristics,
It is possible to realize an illumination means suitable for color imaging that can reproduce a subject with proper 2r-1 contrast and color tone.

[Brief explanation of the drawing]

1 to 5 relate to one embodiment of the present invention, FIG. 1 is an explanatory diagram showing an optical system of a white surface sequential illumination type light source device equipped with one embodiment, and FIG. FIG. 3 is a front view showing a rotating color filter;
FIG. 4 is a perspective view showing the aperture device of one embodiment, and FIG.
A schematic explanatory diagram showing different states of the aperture amount of the aperture constituting the embodiment, FIG. 6 is a configuration diagram showing an endoscope equipped with a light source device for white illumination provided with one embodiment, and FIG. 7 tJ FIG. 8 is an explanatory diagram showing an optical system of a conventional light source device. FIG. 8 is a front view showing a conventional aperture used in the light source device of FIG. 1.41... Endoscope 2... Insertion section 7.7'.
...Video process section 10...Light guide 1.1.42...Light source device 12...Discharge lamp 14...Convex lens 15
...Aperture 16...Gear 17...Motor 23...Adder 24...Integrator circuit
25... Motor drive circuit 31. 32... Annular frame 35... Pin 36... Aperture blade

Claims (2)

[Claims] (1) 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 emitted from the light source in the endoscope light source device that is attached. 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 focusing the emitted illumination light flux and irradiating it to the rear end of the light guide, the center of the illumination light flux is two annular frames arranged opposite to each other so as to be on the optical axis of the frame, and one of which is rotatable relative to the other; bellows-shaped light-shielding aperture blades having one side end fixed along the radial direction, the other side end connected to a portion other than the center of the other frame body, and foldable around the optical axis. A diaphragm device for an endoscope light source device, characterized in that it has a diaphragm composed of. (2) The diaphragm device for an endoscope light source device according to claim 1, wherein the diaphragm is used in a light source device of a color plane sequential illumination type.