JPH10123434A - Light source device for endscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device for endscope in which the color of illuminating light given to a light guide by making light in the vicinity of the center of an illuminating light beam flux incident on the light guide is not changed even in the practically necessary darkest state, in the light source device in which a diaphragm is put in and out to/from an illumination optical path only in one direction of a side. SOLUTION: This light source device has the diaphragm 15 which is put in and out to/from the optical path only in one direction of the side of the illumination optical path toward the illuminating light guide 54 of an endscope from a light source lamp 10, In an effective illumination state just before the light beam flux toward the illumination light guide 51 from the light source lamp 10 is completely shielded by the diaphragm 15, the slit 24 extremely narrow in width for making the light beam of an area 101 near the center of the optical path incident on the light guide 51 is formed at the diaphragm 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device for an endoscope having a stop for adjusting a light flux of illumination light incident on a light guide for illumination of the endoscope.

[0002]

2. Description of the Related Art Illumination light for illuminating an observation range of an endoscope is:
It is necessary to make adjustments so that the image is bright when the distance to the subject is long and dark when the distance to the subject is short.

[0003] For this purpose, generally, a diaphragm that partially blocks an illumination light beam between a light source lamp and an illumination light guide is movably provided so as to change a light shielding area.

There are several types of such diaphragms, but it is the most simple structure to move one diaphragm plate into and out of the optical path from the side of the optical path, and it can be manufactured at low cost. Widely used for light sources for endoscopes.

[0005]

FIG. 8 shows an incident end face 51a of a light guide fiber bundle 51 for illumination of an endoscope connected to a light source device, and a light source lamp 10 of the light source device for illuminating light therethrough. Is shown. 11 is a light emitting unit,
12 is a reflecting mirror.

The illumination light emitted from the light source lamp 10 is
Depending on the type of the light emitting unit 11 (xenon lamp, halogen lamp, etc.), the type of coating of the reflector 12, etc.
Central region 1 of light beam 100 at section A in the middle of the optical path
01 and the peripheral region 102 may have different colors (spectral characteristics).

In many cases, the central region 10 of the light beam 100
Although the color 1 is designed to be close to white light, the peripheral region 102 is bluish, and it is difficult to make the color uniform up to the peripheral region 102. In many cases, as shown in FIG. 9, the central region 101 is bright (large luminous flux) and the peripheral region 102 is dark (small luminous flux).

In the light source device having such characteristics, if one stop plate is moved in and out of the optical path from the side of the optical path, the distance between the subject and the light guide fiber bundle 51 is short.
When reducing the luminous flux of the illumination light to be incident on the object, since only the light around the light flux enters the light guide fiber bundle 51, the illumination light applied to the subject becomes bluish,
The color reproducibility of the endoscope observation image is reduced.

Therefore, for example, as shown in FIG.
A narrow slit 16 is formed in a stop 15 which is rotated about the rotation axis 14 and put in and out of the illumination optical path, and even when most of the illumination light beam is blocked by the stop 15, light near the center is lighted. It is conceivable to make the light enter the guide fiber bundle 51.

However, the width of such a slit 16 is limited due to processing restrictions. For example, it is difficult to manufacture the slit 16 smaller than about 0.3 mm. Therefore, as shown in FIG. 11, in the effective illumination state (the darkest state that is practically necessary) immediately before the illumination light beam 100 is completely blocked by the stop 15, the peripheral area 1 indicated by a hatched line by a broken line
Only the light No. 02 passes through the stop 15 and enters the light guide fiber bundle 51, so that the image observed by the endoscope becomes bluish and good color reproducibility cannot be obtained.

Therefore, the present invention provides a light source device for an endoscope in which an aperture is moved in and out of an illumination optical path only from one side, and the light near the center of the illumination light flux even in the darkest state practically required. An object of the present invention is to provide an endoscope light source device in which the light enters the light guide and the color of the illumination light provided to the light guide does not change.

[0012]

In order to achieve the above object, a light source device for an endoscope according to the present invention adjusts the luminous flux of illumination light entering a light guide for illumination of an endoscope from a light source lamp. A light source device for an endoscope having a diaphragm that is inserted into and removed from the optical path only from one side of the optical path so as to partially block an illumination optical path between the light source lamp and the illumination light guide; In the effective illumination state immediately before the light beam from the light source lamp toward the illumination light guide is completely blocked by the stop, a very narrow width for allowing light rays in a region near the center of the optical path to enter the light guide. A slit is formed in the stop.

The slit may be formed by a gap between a plurality of components along a longitudinal direction of the slit, and the slit may be formed along a moving direction of the diaphragm. It is preferable that the length of the slit is one third or more of the diameter of the light beam at a position blocked by the stop.

The width of the slit may be constant. In this case, the width of the slit may be in the range of 0.01 mm to 0.1 mm. Further, the slit may be formed thinner toward the tip.

[0015] The ridgeline of the bank of the slit may be formed in a knife edge shape.

[0016]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows the light source device 1 for an endoscope, and a light guide fiber bundle 51 for illumination of the endoscope.
The connector 50 in which the incident end is disposed is removably inserted into the socket 2.

The light source device 1 has a built-in light source lamp 10, and various light emitting units 11 such as a xenon lamp or a halogen lamp can be used. The illumination light emitted from the light emitting unit 11 is reflected by the reflecting mirror 12 and converges on the incident end face 51 a of the light guide fiber bundle 51.

An aperture 15 that partially blocks the illumination light path between the light source lamp 10 and the incident end face 51a of the light guide fiber bundle 51 is rotated by a drive motor 18 on a rotating shaft 14.
, And is moved into and out of the optical path from one side of the optical path, thereby changing the light-shielding area of the illumination light flux 100 to change the light flux (brightness) of the illumination light incident on the light guide fiber bundle 51. ) Can be adjusted.

FIG. 3 is a front view of the stop 15 and shows the rotary shaft 1.
4 is moved in the direction of the arrow around the center. 101 is the aperture 1
Illumination ray bundle 100 at the position (cross section) where 5 is arranged
Is a central area, and 102 is a peripheral area.

The aperture 15 has a V-shaped notch 21 formed on one side thereof with the rotational direction (the direction of the arrow in FIG. 3) as the axis of symmetry, and a corner 21a at the top is illuminated. It is arranged at a position passing through the center point of the light beam 100.

The width is, for example, 0.01 mm to 0.1 m from the corner 21 a toward the light shielding portion of the diaphragm 15.
A very narrow slit 24 having a constant width of about m is formed in an arc shape centered on the rotation axis 14 and on a locus passing through the center point of the illumination light beam 100.

It is difficult to machine such a narrow slit 24 directly into the aperture 15. Therefore, a wide slit is formed in the plate portion of the diaphragm 15,
The ridge of the slit is used as one bank in the longitudinal direction of the slit 24, and the small piece 22 fixed to the diaphragm 15 is used as the other bank in the longitudinal direction opposed to the bank.

In this manner, by forming the slit 24 in the gap between the plurality of components 15 and 22 along the longitudinal direction of the slit, the above-described extremely narrow slit can be manufactured relatively easily. .

If the ridgeline of each bank of the slit 24 is formed not in a vertical plane but in a knife edge shape, the slit 2
The effective width of 4 is less affected by the inclination of the surface of the diaphragm 15 and the inclination of the illumination optical axis.

Although the small piece 22 is fixed to the aperture 15 by the screw 23, an adhesive or other fixing means may be used. To adjust the slit width, sandwich the thickness gauge,
What is necessary is just to observe while enlarging with a microscope, a projector, etc.

FIG. 3 shows a so-called fully opened state in which the illumination light beam 100 is not blocked at all by the stop 15. When the stop 15 is rotated from this state, as shown in FIG. The illumination light beam 100 is gradually blocked by the stop 15.

Finally, the stop 15 is used for the illumination light beam 10
0 stops in the effective illumination state (the darkest state necessary for practical use) immediately before it is completely blocked by the aperture 15. FIG. 1 shows the diaphragm 15 in that state.

In a practically darkest state, the illumination light flux passing through the stop 15 must be minimized.
If the width of the slit 24 is large, it is sufficient to allow the light in the peripheral region 102 to pass, and the light in the central region 101 cannot be transmitted.

However, by making the width of the slit 24 extremely small, as shown in FIG. 1, a practically darkest state can be obtained with the tip of the slit 24 reaching near the center of the illuminating light beam 100. it can.

At this time, from the central area 101 to the peripheral area 1
The illumination light passes through only the slit 24 as indicated by the oblique line with a broken line over 02, and light having spectral characteristics almost the same as in the fully opened state enters the light guide fiber bundle 51.

Note that the slit 24 is used to
Has a length of about one third or more of the diameter of the illumination light beam 100 from the outer edge of the light guide bundle 100, light having relatively good spectral characteristics can be incident on the light guide fiber bundle 51.

In the above embodiment, the slit 24 is formed in an arc shape having a constant width. However, the slit 24 may be formed in a linear shape as shown in FIG. 5, or as shown in FIGS. 6 and 7. Alternatively, an arc-shaped tapered slit or a linear tapered slit may be used.

[0033]

According to the present invention, in the effective illumination state immediately before the light beam from the light source lamp to the illumination light guide is completely interrupted by the stop, the light ray near the center of the optical path is incident on the light guide. In the endoscope light source device in which the slit is formed in the illumination optical path only in one side direction, the illumination light beam bundle is formed even in the darkest state required for practical use. Light near the center is incident on the light guide, and the color of the illumination light applied to the light guide does not change, so that an endoscope observation image with good color reproducibility can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged partial front view of a diaphragm in a practically darkest state according to the first embodiment of the present invention.

FIG. 2 is a partial side sectional view of the light source device for an endoscope according to the first embodiment of the present invention.

FIG. 3 is a front view of the diaphragm in a fully opened state according to the first embodiment of the present invention.

FIG. 4 is a front view of the diaphragm in an intermediate state according to the first embodiment of the present invention.

FIG. 5 is an enlarged partial front view of the stop in a practically darkest state according to the second embodiment of the present invention.

FIG. 6 is an enlarged partial front view of the stop in a practically darkest state according to the third embodiment of the present invention.

FIG. 7 is an enlarged partial front view of a stop in a practically darkest state according to the fourth embodiment of the present invention.

FIG. 8 is a partial side sectional view for explaining characteristics of the light source device for an endoscope.

FIG. 9 is a partial side view for explaining characteristics of the endoscope light source device.

FIG. 10 is a front view of a conventional throttle in a fully open state.

FIG. 11 is an enlarged partial front view of a conventional diaphragm in the darkest state in practical use.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Endoscope light source device 10 Light source lamp 15 Aperture 22 Small piece 24 Slit 100 Illumination light flux 101 Central area 102 Peripheral area

Claims (8)

[Claims] In order to adjust the luminous flux of illumination light incident on an illumination light guide of an endoscope from a light source lamp, an illumination optical path is partially blocked between the light source lamp and the illumination light guide. A light source device for an endoscope having a stop that is moved into and out of the light path only from one side of the light path, wherein a light beam traveling from the light source lamp toward the light guide for illumination is completely blocked by the stop; A light source device for an endoscope, wherein an extremely narrow slit is formed in the stop to allow a light ray in a region near the center of the optical path to enter the light guide in the immediately preceding effective illumination state. 2. The slit according to claim 1, wherein the slit is formed by a gap between a plurality of components along a longitudinal direction of the slit.
The light source device for an endoscope according to claim 1. 3. A light source device for an endoscope according to claim 1, wherein said slit is formed along a moving direction of said stop. 4. A light source device for an endoscope according to claim 1, wherein the length of said slit is at least one third of a diameter of said light beam at a position blocked by said stop. 5. The method according to claim 1, wherein the width of the slit is constant.
5. The light source device for an endoscope according to 2, 3, or 4. 6. The light source device for an endoscope according to claim 5, wherein the width of the slit is in a range of 0.01 mm to 0.1 mm. 7. A light source device for an endoscope according to claim 1, wherein said slit is formed thinner toward the distal end. 8. The light source device for an endoscope according to claim 1, wherein a ridgeline of a bank portion of the slit is formed in a knife edge shape.