JPH0720651Y2 - Optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an observation optical system for observing an object and an illumination optical system for illuminating an observation range of the object, such as a surgical microscope, an ordinary microscope, and some cameras. The present invention relates to an optical device including and.

[Conventional technology]

In recent years, microsurgery performed under microscope observation has become widespread, and it has become possible to cure diseases that could not be cured until now. The microscope used for the microsurgery is a stereomicroscope, and the surgeon is supposed to perform surgery while viewing stereoscopically. Due to recent advances in electronics, still cameras and video cameras are equipped with an autofocus function, enabling automatic focusing.
It is also desired to add an autofocus function to improve the operability of a surgical microscope. Especially in the case of a microscope, the depth of focus is shallower than that of the camera, and if the observed object is out of focus, it will be greatly blurred. Since there were many cases, the above request was stronger.

In the field of stereoscopic microscopes, Japanese Patent Publication No.
-55123 and Japanese Patent Laid-Open No. 57-158826. In both cases, an index is projected on the object surface, the reflected light is detected by a light receiving element, and the deviation of focus and its direction are verified by the detection signal. Further, as described in Japanese Patent Application Laid-Open No. 63-256932, which is common to a microscope and a camera, a projection image of a split prism placed on a position conjugate with an image pickup surface onto an object has a position conjugate with the image pickup surface. There is a method for detecting a focus shift and its direction by projecting it on a photoelectric element in (1) and detecting the division amount of the projected image.

[Problems to be solved by the device]

However, as described in JP-B-57-55123 and JP-A-57-158826, when the index projection light has the same wavelength as the observation light or the same wavelength as the illumination light of the illumination system not shown,
Since the index projection light and the observation light cannot be separated and focus detection cannot be performed, the index projection light must use a wavelength different from the observation light or the illumination light, for example, infrared light.

Also, in Japanese Patent Laid-Open No. 63-256932, the use of projection light at different wavelengths is not shown, but the same can be said. That is, if the size of the projected image is equal to or larger than the observation field of view obtained by the objective lens, if the divided projected images 30, 30 match as shown in FIG. Although it can be detected by the photoelectric element 31, as shown in FIG. 12 (b), when the divided projected images 30, 30 deviate from each other, the portions outside the visual field 32 are eclipsed in the optical path to cause the vignetting portion 33, resulting in division. The captured images 30, 30 are no longer projected on the one-dimensional photoelectric element 31 in perfect form. Therefore, if focus detection is carried out by the method disclosed in Japanese Patent Laid-Open No. 63-256932, a combination of divided projection images 30, 30 as shown in FIG.
It must be sufficiently smaller than 2, so an additional illuminator is needed to illuminate the entire field of view for observation. If a separate illuminating device is provided, the projection image must be separated from the observation image or the illumination light in order to detect only the projection image. Therefore, the projection light has a wavelength different from that of the illumination light or the observation light. Inevitably, the means to do is necessary.

Therefore, these focus detection devices cannot see the index light with the naked eye, and in addition to the illumination device for observation, the index projection device, the separating means for the projection light and the observation light, the light receiving device and the light receiving device. There is a problem in that an arithmetic unit for calculating the focus shift amount and the direction based on the signal from is necessary, which is expensive. In particular, because a special optical system is required, if this is built into the microscope, the size of the microscope becomes large and the operability deteriorates, and even if the existing microscope is modified, it cannot be easily installed. There was a problem that it was very uneconomical because I had to buy a new dedicated mirror body.

Further, in these focus detection devices, it is difficult for the device itself to determine which position to focus on when the projections and depressions are severe as in the surgical site, and the shape of the index itself collapses so that the focus is focused. The movement does not converge,
It is easy for the operator to focus on an unnecessary position, and the operator often refocuses the image with appropriate judgment, resulting in poor reliability and impracticality.

In view of the above problems, the present invention makes it possible for the operator to easily and accurately recognize the direction of focus deviation when the observation image is greatly blurred due to focus deviation, even if the operator performs a minute focus adjustment. It is an object of the present invention to provide a highly reliable and practical optical device that can be used by simply modifying the existing optical device.

[Means and Actions for Solving the Problems]

An optical device according to the present invention is an optical device comprising an observation optical system for observing an object and an illumination optical system for illuminating an observation range of the object, wherein an object-side focus surface of the observation optical system in the illumination optical system and By placing an image splitting optical element in the vicinity of the conjugate position so that when the focus shifts, part of the illumination field moves relative to other parts, so that special features such as the index projection device etc. Without using a simple optical system or additional equipment,
The operator can recognize the direction of out-of-focus with the naked eye.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a schematic view of the optical system of the stereoscopic microscope according to the first embodiment as viewed from the side, where F is a focusing surface, 1 is an objective lens, 2 is an observation variable magnification optical system for changing the observation magnification, 3 Is an observation optical system, and O is an operator. When an object is on the focusing surface, the operator O can observe an enlarged image of the object in a focused state. The observation variable magnification optical system 2 and the observation optical system 3
Although only one set is shown, in reality, there is another set in a plane perpendicular to the paper surface to enable stereoscopic viewing. Reference numeral 4 is a light guide for guiding illumination light from a light source (not shown), 5 is a relay lens, 6 is a prism, 7 is a variable-magnification optical system for changing the size of the illumination field in response to a change in observation magnification, and 8 is a prism. A circular split prism 9 composed of semi-circular prisms 9a and 9b having inclined surfaces in opposite directions as shown in FIGS. 2 (a) and 2 (b) in the vicinity of a position C conjugate with the focusing surface F. Are arranged.

Since the present embodiment is configured as described above, the illumination light emitted from the light guide 4 passes through the relay lens 5, the split prism 9, the prism 6, the illumination variable-magnification optical system 7 and the prism 8 and the observation optical system. The observation site is illuminated through the objective lens 1 common to the system. When the observation area is on the focus plane F, the observation area is illuminated in a substantially circular shape, and the illumination field is the third area.
It becomes like the range I _A as shown in the figure. However, for example, the near surface where the observed portion is closer to the objective lens 1 than the focus surface F is
When in the F _n, when viewed from the operator, illumination field FIG. 4 (a) ranges divided in the vertical direction on the left and right as shown in I _A '
Becomes Further, the observation portion is the objective lens 1 rather than the focus plane F.
When it is on the far surface F _f away from the illuminating field, the illumination field is in the range I _A ″, which is divided in the up and down direction opposite to I _A ′ as shown in FIG. 4 (b). When the operator O visually observes without passing through the observing optical system 3, the deviation of the illumination field differs depending on the direction of focus deviation, so that the direction of focus deviation can be known and the focusing operation can be performed easily. Even if O observes the surgical site (observation site) through the observation optical system 3, if the observation site is on the near surface F _n , as shown in FIG.
Non-illuminated area B that is dark because it is not illuminated in the observation field of view A _o
Appears. Similarly, if there is an observation site on the far surface F _f ,
As shown in FIG. 5 (b), the non-illumination part B appears at a position different from that shown in FIG. 5 (a). Therefore, the operator can know the direction of the focus shift at a glance and can easily perform the focusing operation. Further, in this embodiment, as can be seen from FIG. 5, the moving part of the illumination field due to the focus shift is large,
It is easy to recognize even if it is greatly blurred. Further, the operation interruption time at the time of focusing can be shortened and the mental fatigue of the operator can be reduced, so that the safety of the operation is enhanced. Further, it is inexpensive because no special optical system or additional device is required and only the existing mirror body is simply modified.

FIG. 6 shows an optical system according to the second embodiment, which has a prism plate 10 on the light guide 4 side near the conjugate position.
However, illumination field diaphragms S _F each having a circular opening are arranged on the prism 6 side. The prism plate 10 has a circular plate 10 as shown in FIGS. 7 (a) and 7 (b).
A strip-shaped prism 10b is provided along the diameter of the center of a, and the prism 10b serves as a split prism.

This embodiment, from being configured as described above, similarly to the first embodiment, the prism plate 10, illumination passing through the apertures of the illumination field stop S _F is irradiated to the observation site. If the observation site is the focal plane F, the observed region is projected circular aperture of the illumination field stop S _F, the illumination field in the range of circular as shown in FIG. 8
I _B. When the observation site is on the near surface F _n , the illuminating area seen by the operator is a range having a recess T ″ as shown in FIG. 9 (a).
It becomes like I _B ′. When the observation site is on the far surface F _f ,
As shown in FIG. 9 (b), the illumination field has a region I _B ″ having a recess T ″ at a position opposite to I _B ′.

Therefore, similarly to the first embodiment, the operator can confirm the focus shift due to the displacement of a part of the illumination field, whether visually or through the observation optical system 3. Moreover, since the contour of the illumination field becomes clear due to the presence of the illumination field diaphragm S _F , it is easy to detect the deviation of the illumination field. Further, as shown in FIG. 9, when the concave portion T'in the upper part of the illumination field is generated, the observation site is on the objective lens 1 side of the focus plane F, so that the focus should be moved upward, and the concave portion in the lower part. When T ″ is present, the observation site is below the focus plane F, so it is sufficient to focus on the lower side. Therefore, the direction of focus deviation and the focusing operation direction can be easily recognized, so that accurate focusing is possible. You can work.

FIGS. 10A and 10B show a prism plate 11 of the optical system of the third embodiment, which is used in place of the prism plate 10 in the same optical system as the second embodiment. The circular plate 11a is provided with prisms 11b and 11c on two opposite peripheral portions of the circular plate 11a,
The prisms 11b and 11c function as a split prism.

Since the present embodiment is constructed as described above, when the observation site is on the near surface F _n , the illumination field becomes like the range I _c ′ as shown in FIG. _When it is at _f, it is shown in Fig. 11 (b).
As shown in Fig. 2, the range I _c ″ is obtained. Therefore, when the observation optical system 3 observes the focus, the moving portion M appears to be displaced from the observation visual field.
As in the case of the embodiment and the second embodiment, the direction of the focusing operation can be recognized from the direction in which the moving portion M is displaced. Also, unlike the first and second embodiments, the illumination field in the central portion does not move, so that the illumination field in the central portion is not lost even if a large unevenness is seen, which is extremely safe for surgery.

[Effect of device]

As described above, the optical device according to the present invention allows the operator to easily and accurately recognize the direction of defocusing when the observation image is greatly blurred due to defocusing, even if the operator performs fine focusing, and is inexpensive. Therefore, it has an important advantage that it is highly reliable and practical, such that it can be used by simply modifying the existing optical device.

[Brief description of drawings]

FIG. 1 is a schematic view of an optical system of a stereoscopic microscope which is a first embodiment of an optical device according to the present invention, and FIGS. 2A and 2B are a plan view and a side view of a split prism of the first embodiment, respectively. , FIG. 3 and FIG. 4 are diagrams showing the change of the illumination field in the first embodiment, and FIG. 5 is a diagram showing the relationship with the observation visual field when the illumination field of the first embodiment is changed, FIG. Is a schematic view of the optical system of the second embodiment, FIGS. 7A and 7B are a plan view and a side view of the prism plate of the second embodiment, FIGS. 8 and 9 respectively.
FIG. 10 is a diagram showing a change in illumination field in the second embodiment, FIGS. 10 (a) and 10 (b) are a plan view and a side view of a prism plate of the third embodiment, and FIG. 11 is a view in the third embodiment. FIG. 12 is a diagram showing changes in the illumination field, FIG. 12 is a diagram showing changes in the division projection image when the projection image is equal to or larger than the observation field of view in the conventional example, and FIG. 13 is a projection image in the conventional example FIG. 7 is a diagram showing a change in a division projection image when the size is sufficiently smaller than that. F ... Focus surface, 1 ... Objective lens, 2 ... Observation zoom optical system, 3 ... Observation optical system, O ... Operator, 4 ... Light guide, 5 ... Relay lens, 6, 8 ... … Prism, 7 ……
Variable magnification optical system, 9 ... Split prism, 10,11 ...
… Prism plate, C… Conjugate position, S _F …… Teruno field diaphragm, I _A , I _B , I _C …… range of illumination field, A _O …… Observation field of view, B…
... Non-illumination part, T ', T "... recessed part, M ... moving part.

Claims (1)

[Scope of utility model registration request] 1. An optical device comprising an observation optical system for observing an object and an illumination optical system for illuminating an observation range of the object,
An optical device characterized in that an image division optical element is arranged in the illumination optical system in the vicinity of a position conjugate with the object-side focus surface of the observation optical system.