JP3623817B2 - Endoscope light source device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an endoscope light source device.
[0002]
[Prior art]
In the endoscope light source device, it is necessary to be able to adjust the luminous flux (brightness) of the illumination light incident on the endoscope illumination light guide from the light source. Therefore, in general, light flux adjustment is performed by sandwiching the illumination beam bundle from the side and opening and closing the pair of light blocking stops from both sides to change the area of the illumination beam bundle incident on the light guide.
[0003]
FIG. 5 is a front view of such a conventional light-shielding diaphragm 51, 51 so that the open / close center line A of the light-shielding diaphragms 51, 51 coincides with the central axis B of the illumination beam bundle 100 directed from the light source to the light guide. Are arranged symmetrically. The shaded portion is a light beam that is not shielded by the light-shielding stops 51 and 51 and enters the light guide.
[0004]
[Problems to be solved by the invention]
However, in the vicinity of the central portion of the illumination beam bundle 100, the luminous flux per unit area is larger and brighter than the peripheral portion. Therefore, when the light blocking stops 51, 51 are narrowed down, the light blocking stops 51, 51 are opened and closed. On the other hand, there is a drawback that fine brightness adjustment cannot be performed because the change in the luminous flux of the illumination light incident on the light guide is too large.
[0005]
Therefore, an object of the present invention is to provide an endoscope light source device that can perform fine brightness adjustment even when the light-shielding aperture is opened and closed, even when the light-shielding aperture is narrowed.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an endoscope light source device according to the present invention illuminates between a light source and an incident end of an illumination light guide of an endoscope into which illumination light emitted from the light source is incident. In an endoscope light source device that adjusts the luminous flux of illumination light incident on the light guide by opening and closing the light-shielding stop so as to block the light bundle, the open-close center line of the light-shielding stop is defined as the illumination light beam. The arrangement is characterized by being shifted from the central axis of the bundle.
[0007]
The opening / closing amounts of the pair of light-shielding diaphragms may be different from one to the other.
[0008]
【Example】
Embodiments will be described with reference to the drawings.
In FIG. 2, 1 is an insertion part of an endoscope, and 2 is an objective lens disposed at the tip thereof. The light-receiving surface of the solid-state imaging device 3 is disposed at a subject imaging position by the objective lens 2. However, an image guide fiber bundle may be used instead of the solid-state imaging device 3.
[0009]
Reference numeral 4 denotes an illumination light guide fiber bundle for transmitting illumination light that illuminates the visual field range of the objective lens 2, and the observation site is illuminated by the illumination light emitted from the emission end portion 4 a.
[0010]
Reference numeral 10 denotes a light source device for supplying illumination light to the light guide fiber bundle 4, and an incident end 4b of the light guide fiber bundle 4 is detachably inserted.
[0011]
The illumination light emitted from the light source lamp 11 arranged in the light source device 10 is converged on the incident end 4 b of the light guide fiber bundle 4 by the elliptical reflecting mirror 12 and enters the light guide fiber bundle 4.
[0012]
The illumination beam bundle 100 is sandwiched from the side so that the illumination beam bundle 100 is blocked between the light source lamp 11 and the incident end portion 4b of the light guide fiber bundle 4, and a pair of light shielding stops 13 can be opened and closed from both sides. Is arranged. The light-shielding diaphragm 13 is driven to open and close by a step motor 14.
[0013]
FIG. 1 is a front view of the light shielding diaphragm 13 (13 a, 13 b) portion, and the opening / closing center line A of the light shielding diaphragms 13 a, 13 b is shifted from the central axis B of the illumination beam bundle 100.
[0014]
In this embodiment, the open / close center line A is arranged vertically so that the light-shielding stops 13a and 13b are opened / closed from both the left and right sides with respect to the illumination beam bundle 100, which is the central axis B of the illumination beam bundle 100. On the other hand, they are shifted to the left as viewed from the front.
[0015]
Therefore, since the right light-shielding stop 13a needs to shield the illumination light beam 100 with a wider width than the left-hand light-shielding stop 13b, it is formed wider than the left-hand light-shielding stop 13b.
[0016]
The right light-shielding diaphragm 13a is directly connected to the rotation shaft of the step motor 14, is driven to rotate about the rotation shaft 15a, and the stop position is controlled in units of one step of the step motor 14.
[0017]
On the other hand, the left light-shielding stop 13b is driven to rotate about the rotation shaft 15b of the second gear 16b that meshes with the first gear 16a attached to the rotation shaft 15a of the step motor 14. In this embodiment, since the first and second gears 16a and 16b have the same number of teeth, the right light shielding stop 13a and the left light shielding stop 13b are opened and closed by the same amount in opposite directions.
[0018]
In the embodiment apparatus configured as described above, as shown in FIG. 1, the light-shielding stops 13 a and 13 b are opened and closed on both sides of the opening / closing center line A shifted from the center axis B of the illumination beam bundle 100. The
[0019]
As a result, when the light-shielding stops 13a and 13b are narrowed, illumination light near the open / close center line A that is not as bright as near the central axis B of the illumination beam bundle 100 enters the light guide fiber bundle 4.
[0020]
Therefore, since the amount of change in the light beam incident on the light guide fiber bundle 4 is small with respect to the minimum movement amount of the light-shielding diaphragms 13a and 13b that are opened and closed by the rotation of the step motor 14 for one step, the brightness of the illumination light is reduced. It can be finely adjusted.
[0021]
FIG. 3 shows a second embodiment of the present invention, in which the number of teeth of the first gear 16a directly connected to the step motor 14 is smaller than the number of teeth of the second gear 16b, and the outer periphery of the illumination beam bundle 100 is shown. The opening / closing amount of the left light-shielding diaphragm 13b is smaller than the opening / closing amount of the right light-shielding diaphragm 13a.
[0022]
By doing so, the amount of movement of the left light-shielding stop 13b due to the rotation of the step motor 14 by one step is reduced, so that the amount of change of the light beam incident on the light guide fiber bundle 4 is further reduced, and the illumination light Brightness can be adjusted more finely.
[0023]
FIG. 4 shows the rotation angle of the step motor 14 and the incident light beam (brightness) on the light guide fiber bundle 4 in the case of the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. This is a comparison between the case (3) of the example and the case (5) of the conventional example shown in FIG.
[0024]
In the case of the second embodiment (3), the ratio of the number of teeth of the first gear 16a and the number of teeth of the second gear 16b is set to 1: 2, and the opening / closing amount of the left light-shielding diaphragm 13b is set to the right side. The case where it is half of the light-shielding stop 13a is shown.
[0025]
In FIG. 4, the smaller the slope of the curve, the smaller the change in the incident light beam (brightness) to the light guide fiber bundle 4 with respect to the rotation angle of the step motor 14, and fine brightness adjustment can be performed. The order is (3), (1), (5).
[0026]
The present invention is not limited to the above-described embodiments, and for example, the specific shape and operation of the light-shielding diaphragm can take various forms.
[0027]
【The invention's effect】
According to the present invention, the opening / closing center line of the light-shielding stop is arranged so as to be shifted from the central axis of the illumination beam bundle, so that when the light-shielding aperture is narrowed, the opening / closing center is not as bright as the vicinity of the center axis of the illumination beam bundle Illumination light near the line enters the light guide. As a result, the amount of change of the light beam incident on the light guide becomes small with respect to the opening / closing amount of the light-shielding diaphragm, and the brightness of the illumination light can be finely adjusted.
[0028]
Then, by making the opening / closing amounts of the pair of light blocking diaphragms different from one to the other, the amount of change in the light beam incident on the light guide is further reduced with respect to the movement amount of the light blocking diaphragm, and the brightness of the illumination light is further increased. It can be finely adjusted.
[Brief description of the drawings]
FIG. 1 is a front view of a light-shielding stop portion according to a first embodiment.
FIG. 2 is an overall schematic diagram of the first embodiment.
FIG. 3 is a front view of a light-shielding stop portion of a second embodiment.
FIG. 4 is a characteristic diagram of an example and a conventional example.
FIG. 5 is a front view of a light-shielding stop portion of a conventional example.
[Explanation of symbols]
4 Light guide fiber bundle 4b Incident end 11 Light source lamps 13a and 13b Light-shielding stop 14 Step motor 100 Illumination beam bundle A Opening / closing center line B Center axis of illumination beam bundle

Claims (2)

The light guide is opened and closed by opening and closing a pair of light-shielding stops so as to block the illumination beam bundle between the light source and the incident end of the illumination light guide of the endoscope to which the illumination light emitted from the light source is incident. In an endoscope light source device that adjusts the luminous flux of illumination light incident on the endoscope,
And staggered closing center line of the pair of light blocking aperture from the center axis of the upper Symbol illumination ray bundle, the closing speed of the throttle shielding those who do not obstruct the central axis of the illumination ray bundle of the pair of light blocking aperture An endoscope light source device, wherein the light source device is set slower than the opening / closing speed of the light-shielding diaphragm that shields the central axis of the illumination beam bundle . The endoscope light source device according to claim 1, wherein ridge lines of portions of the pair of light-shielding diaphragms that move in the illumination beam bundle are each formed in a straight line.

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