JPS5866910A - Illuminating optical system for endoscope - Google Patents

Abstract

PURPOSE:To uniformly illuminate both near object point and for object point by sufficient light quantity, even in case of a wide angle endoscope whose view angle is >=60 degrees, by obliquely placing at least one reflection surface, and also providing a concave lens or a convex lens in front of the reflection surface. CONSTITUTION:A concave lens 10 is placed in front of an optical element consisting of a prism 6 and 7. In a light beam emitted from a light guide 1, a light beam which has transmitted the inside of the prism 6 and 7 is expanded by the concave lens 10. Accordingly, when a curvature and a refractive index of the concave lens 10 are selected suitably, it is possible to uniformly illuminate a far object point, even in case of an endoscope whose angle is >=60 degrees. On the other hand, in the light beam emitted from the light guide 1, a light beam reflection surface 8 is emitted from the prism 7 with an emitting angle theta, also is expanded by the concave lens 10, and is emitted from the concave lens 10 with the emitting angle theta.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to an illumination optical system for private celebration ψ, which is capable of uniformly illuminating the distance from the far point to the near point plate.

Figure 1 shows the structure of the tip of a conventional endoscope with an angle of view of 60n degrees. The light guide 1 and the Cummer glass 2 constitute an illumination optical system, and the image chi'3, the objective lens 4, and the cover glass 5 constitute an observation optical system.

By the way, the bush specimen that should be observed is the periapsis object point (
The range extends from the virtual object at position (a) in FIG. 1 to the distant object point (the sample '4i at position (b) in FIG. 1). Generally, the spread angle of the light emitted from the light guide 1 is about 300 to 35 degrees, so the far point object point (
(b) When inspecting, the area of the yoke can be uniformly illuminated as shown in the figure, which saves practical time.

However, it should be noted that the variation of the illumination optical system and observation optical system affects the observation of the periapsis object point (a). The drawback was that it was difficult to generate cost sources.

Conventionally, in order to improve this drawback, two prisms 6.7, which are oblique with respect to the axis of the light guide 1, are used instead of the conventional cut-glass 2 shown in FIGS. 2 and 3. A configuration has been proposed in which an optical element including a reflective surface 8 and a second reflective surface 9 facing the reflective surface 1fY8 is provided.

In this case, the reflective surface 8 is formed by interposing a reflective film, or the prisms 6 and 7 are slightly separated and there is air between them. - is formed so that the light beam from the light guy P1 can be totally reflected. According to such an illumination optical system, the leading light beam emitted from the light guide 1, which is reflected by the reflective surface 8, is reflected again by the second reflective surface 9, and is then returned to the temporary specimen at an emission angle θ. cormorant. Therefore, the direction of this ray is set to the periapsis point and the point (
b) as #! If it matches the direction of the subject to be worshiped, the Noklarax will be removed and served. On the other hand, the light beams transmitted through the prisms 6 and 7 illuminate the front with a spread angle equal to the spread angle of 300 to 3 degrees of the light guide 1, so when weighing the far point #I point (b), Is the above conventional 1? As in the case of lJ, the area around the ':Lq festival membrane can be uniformly illuminated. In this way, by using the illumination optical system as shown in Figures 2 and 3, the periapsis object point (a) can be set to F! Whether you are performing a ritual or observing a single point, you can obtain even and sufficient light.

However, when the plane angle of the optical axis exceeds 6CP, the illumination optical system of the upper S-plane becomes insufficient in the peripheral area, and cannot be put to practical use. In order to solve this problem, a hit illumination optical system shown in FIG. 4 has been proposed. That is, according to this illumination optical system, the concave lens 1 is disposed between the light guide 1 and the optical element consisting of the prisms 6 and 7.
O and d are intervening. Therefore, the light emitted from the light guide 1 is bent outward by the concave lens 10, passes through the prism 6.7, and is emitted with an angle of 1. This exit angle can be adjusted arbitrarily by appropriately selecting the curvature and refractive index of the concave lens 1o, so if it is determined that the illumination light spreads to a range that can sufficiently obtain the angle of view of the observation string. good. However, in this illumination optical system, the light rays emitted from the light guide 1 are bent by the concave lens 10 and then transmitted through the prisms 6 and 7, so they are cut off by the side surfaces of the prisms 6 and 7 and photoelectrons are generated in the periphery. There is a drawback that the value decreases. In order to overcome this drawback, the outer diameters of the prisms 6 and 7 may be increased, but this solution cannot be adopted in practice considering the dimensional limitations of the endoscope.

In this way, a variety of configurations have been proposed as illumination optical systems for endoscopes, but there are still only a few with an angle of view of 60
In an endoscope of 0 or more, there is no possibility of an illumination optical system capable of uniformly illuminating the periphery of the field of view with sufficient luminous intensity without any ξ rarax, and a mountain-like shape is desired.

In view of the above-mentioned circumstances, it is an object of the present invention to provide an illumination optical system capable of uniformly illuminating both the near-point object point and the lotus-point object point using a sufficient light meter even in a wide-angle endoscope having an angle of view of 6CP or more. However, this will be explained below based on the illustrated embodiment. In the description of the embodiment, concave or similar elements to those in the conventional example already explained will be designated by the same reference numerals.

First, practical examples showing the basic configuration of the present invention are shown in Section 5 and FIG. This point is basically different from the fjH example, and the other parts are the same as the conventional example, so a detailed explanation will be omitted. According to this embodiment, the light beams that have passed through the prisms 6 and 7 are spread out by the concave lens 10, among the light portions that are emitted from the light guide 1 through JJ.

Therefore, if the curvature and refractive index of the concave lens 10 are set appropriately >IY, it is possible to uniformly illuminate the far point even with an endoscope having both angles of 60° or more. It's Hi. On the other hand, out of the light emitted from the light guide 1, the optical property reflected by the reflection r+1'i8 is the emission angle θ
The light is emitted from the prism 7 with an angle of emitted from the concave lens 10, and is further expanded by the concave lens 10 and emitted from the concave lens 10 with an emitted angle θ. Conveniently, the curvature and curvature of the concave lens 10 are selected as the five-speed lens, and the reflective surface is set so that the light rays emitted in parallel from the center of the light guide 1 are reflected at the center of the reflective surface 8. 8, it is possible to uniformly illuminate the required periapsis object point range with a sufficient amount of light, no matter what kind of deity has an angle of view of 60 degrees or more.

This explanation differs from the conventional example shown in FIG. 4 in that the concave lens is basically placed in front of the optical element consisting of prisms 6 and 7, but the present invention In the case of This has the advantage that it can be applied to 1fiIN within a wide angle.

FIG. 7 shows 11! of the present invention which is slightly different from the previous embodiment! ! According to this embodiment, light beams are emitted in parallel from the center of light guy F:'1 and reflected...1
By arranging the relative position 1 of the prism 6.7 and the concave lens 10 so that the chief ray that goes back through the center of the prism 8 and is reflected by the second reflective surface 9 passes through the center of the curved surface of the concave lens 10, The principal light beam is emitted from the concave lens 10 at an exit angle θ, and as a result, the required periapsis object point range can be uniformly illuminated with a sufficient amount of light. By this lifting as shown in Fig. 8, the emission angle θ can be made smaller than in the case of the arrangement shown in Fig. 7, and conversely, as shown in Fig. 9,
The exit angle θ can also be made larger than in the arrangement shown in FIG. Therefore, according to the present invention, there is an advantage that by moving the concave lens 10, the exit angle θ can be changed in accordance with the distance −11 at the near-point proximal point to be used.

Figure I@10 shows an example of an actual printing using a convex lens 11 instead of the concave lens 10. According to this implementation, the focal length of the convex lens 11 is changed depending on the angle of view of the mirror, or the shape of the optical element consisting of the prism 6.7 is changed, so that the light rays of the convex lens 11 and the light guide 1 are The illumination range can be changed by changing the distance from the exit end face (light source section for illumination). This will be explained in detail below with reference to FIGS. 11 to 13 in which the prisms 6.7 are omitted. In Figure 11,
Light guide 1 is placed at the rear focal point (F8) position of convex lens 11.
A case is shown in which the spread angle ω1 is obtained by placing the ray exit end face of . Further, FIG. 12 shows a case where a large spread angle ω2 can be obtained by placing the light beam exit end face of the light guide 1 behind the rear focal point position of the convex lens 11. Furthermore, FIG. 13 shows a case in which a spread angle ω3 intermediate between the above two spread angles ωl and ω2 is obtained by placing the light exit end face of the light guy P1 in front of the rear ii'tl+focal position of the convex lens 11. It is shown. In this way, when using a convex lens, the wide viewing angle can be arbitrarily changed by keeping the relative position between the lens 11 and the light guide 1 constant and changing the focal length, that is, the refractive power of the lens 11. be able to. Therefore, even in an endoscope with an angle of view of 600 or more,
The spread of the first set can be increased if necessary, and the field of view can always be uniformly illuminated with a sufficient light meter. If the angle of view is 60 degrees or less, the spread angle should be made smaller to make the illumination range smaller so that the field of view can be illuminated evenly. Note that, as is clear from the following sections, the same result can be obtained by setting the distance between the lens 11 and the light guide 1 to be 4.degree., as schematically shown in FIG.

That is, in FIG. 14, convex lenses 11 with the same focal length
On the other hand, when the light emitting end surface of the light guide 1 is moved along the optical axis, when the end surface is at position A, the spread angle of the light beam is ω4, and the vagina! When the surface of η is also at about dB, the spread angle becomes ω8, and the spread angle ω8 becomes larger than ω4.

FIG. M2S shows a further example of the present invention in which a concave lens 12 is interposed between the light guide 1 and an optical element consisting of a prism 6.7.

This embodiment also makes it possible to obtain a sufficiently large spread angle of the light beam in spite of the case of the actual Mj yll described above, the open door, and the small size.

Next, a numerical example of the illumination optical system according to the present invention will be shown using FIG. 16 (the embodiment shown in FIG. 7).

a=3φθ! =45° n+ =1.62004
ν, =36.3b=o, s 5 θ2=62
° n2 = 1.62004 1'2 = 36.3
c=o, 9 θ3=65.3° r+3=1.78
472 C3=25.7d=2.2φ e=0.8 Note that a is the outer diameter of the lens 10, b is the width of the side surface of the lens 10, and C is the thickness of the prism 6.7 in the optical axis direction.

d is the outer diameter of the light guy P1, e is the distance between the edge of the prism 7 and the rear edge of the reflective surface 8, θ1 is the angle between the front surface of the prism 7 and the reflective surface 8, and θ2 is the prism nosm. The angle θ3 between the front surface of the prism 6 and the second reflective surface 9 is the light beam force emitted from the center of the light guide 1; the angle K + n+ +'2 and n3 are the angles emitted from the concave lens 10, respectively. 7 and the refractive index of the concave lens 10, sil, shi 2
．． 3 is the Atsbe number of the prism 6.7 and the concave lens 10, respectively. Also, the curvature of the concave lens 10 is 2.498R.
Demeru.

In each of the above embodiments, the second reflective surface 9 is described and explained as having a flat surface, but as shown in FIG. 47 for a button, this reflective surface is a part of a spherical surface. It may be curved to form a shape.

If this second reflective surface 9 is curved, it is possible to concentrate the light rays to a certain extent at a specific position, and it is possible to create a bright illumination area similar to spot illumination at the periapsis moving point.

As described above, according to the present invention, the number of parts and dimensions can be reduced compared to the conventional illumination optical system! It is possible to provide an illumination optical system capable of uniformly illuminating the entire observation visual field with sufficient light intensity even for a wide-angle internal viewing ladder with an angle of view of 60° or more without increasing W.

[Brief explanation of the drawing]

Fig. 1 shows the main parts of a conventional endoscope with a small angle of view, and Fig. 2 shows a conventional endoscope that is configured to remove parallax in the inner endoscope with a small angle of view. Kyo indicating lJ, 3rd
The figure is an enlarged view of the illumination optical system in Figure 2, and Figure 4 is an enlarged view of the illumination optical system in Figure 3.
An enlarged view showing another conventional example corresponding to the figure, Fig. 5 is from Book II.
1. Figure 6 is an enlarged view of the illumination optical system in Figure 5, and Figure 7 is the illumination optical system according to the present invention. FIG. 8 is an enlarged view showing another embodiment in which the concave lens is shifted in one direction in the embodiment shown in FIG. FIG. 10 is an enlarged view showing still another embodiment of the illumination optical system according to the present invention, and FIG. Figures I to 13 are explanatory diagrams showing changes in the spread of illumination light when changing the refractive power of the convex lens in the embodiment shown in Figure M2O, and Figure 14 is an explanatory diagram showing changes in the spread of illumination light when the refractive power of the convex lens is changed in the embodiment shown in Figure M2O.
An explanatory diagram showing how the spread of illumination light changes by changing the distance between the convex lens and the light guide in the embodiment shown in the figure, and FIG. 15 shows still another embodiment of the illumination optical system according to the present invention. The enlarged view shown in FIG. 16 is a diagram for explaining one numerical example of the illumination optical system according to the present invention. 1...Light guide, 3...Image guide, 4...
...Objective lens, 5...Cover glass, 6.7...
Prism, 8... Reflective surface, 9... Second reflective surface, 1
0...Concave lens, 11...Convex lens. Figure 3 Figure 4 Figure 7 10 Figure 5 Figure 16 ~ Off Figure 0 18 Figure 7 19 Figure 0 Figure 10 Figure 1 Seal Figure I

Claims (1)

[Scope of Claims] (1) At least one reflecting surface that reflects a part of the light from the cough lighting light source is provided in front of the lighting light source section, and is obliquely r41 with respect to the optical axis of the illumination optical system. An illumination optical system for an endoscope, further comprising a concave lens or a convex lens provided in front of the reflective surface. (The illumination optical system for an endoscope according to claim (1), wherein one of the 23 m reflecting surfaces is provided on the optical axis of the illumination optical system. (3) The illumination light source section and the lens A second reflective surface is provided in between, facing the reflective surface Nll, and the second reflective surface P' further reflects the light reflected by the reflective surface and directs it toward the lens. Claims (
1) or (2), the illumination optical system for private use.