JP2003329934A - Vertical illuminating method and optical device using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical illuminating method for obtaining sufficient brightness and resolution, and an optical device which implements the method and whose structure is miniaturized. <P>SOLUTION: The optical device (1) has a lens (2) forming the image of an object and at least one light emitting part (4a) vertically illuminating the object. The light emitting part (4a) is arranged to face to the outside part of the image side surface (2d) of the lens, and illuminates the object through the outside part of the lens and also secures an optical path through which reflected light from the object passes at the center part of the lens. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of illuminating an object to be observed substantially along a lens (hereinafter referred to as epi-illumination proof). Although this method is not limited in its use, it is preferably used for a rigid endoscope, a fiberscope, etc., and the present invention also relates to such an optical device.

[0002]

2. Description of the Related Art Generally, an optical device of the above-mentioned type is capable of illuminating an object by epi-illumination and capturing reflected light with a lens.
This is a configuration for obtaining an image of an object.

In epi-illumination, a semi-transparent half mirror is typically provided in the middle of the optical path on the eyepiece side or the image side of an optical instrument, and light from outside the optical path is bent by this half mirror to pass an object through a lens. It is done by illuminating. Such a system can be seen, for example, in “Practical Hikari Keyword Dictionary”, published by Asakura Shoten (April 1999), FIG. 9.9 on page 82. In addition, as another epi-illumination system, Japanese Patent Laid-Open No. 9-23889
Japanese Patent Publication No. 2 discloses that a plurality of illumination light transmission fibers fixed around the objective optical system are used.

[0004]

In the illumination method using the half mirror described above, the illumination light is reflected at the central portion of the lens surface, and a part of the reflected light from the object is transmitted through the half mirror or the half mirror. It is reflected and diffused by the object, and the brightness and resolution of the image of the object are reduced. On the other hand, in the method of arranging the illumination optical fiber around the objective optical system, it is difficult to accurately direct the illumination light to the object, and the size of the tip of the device becomes large, which is not suitable for observing minute parts. Have difficulty.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an epi-illumination method capable of obtaining sufficient brightness and resolution. Another object of the invention is to provide an optical device for carrying out the above method, which is compact in structure.

To achieve the first object, the epi-illumination method according to the present invention guides illumination light to an object through an outer portion of an optical path of a lens system for forming an image of the object, and reflects light reflected from the object. It is characterized in that it passes through the central part of the optical path of the lens system. According to this configuration, the light from the light emitting portion illuminates the object through the outer portion of the optical path of the lens system, and the reflected light from the object passes through the central portion of the optical path of the lens system and is blocked by the light emitting portion. There is no. Therefore, the image of the object has sufficient brightness and good resolution.

To achieve the second object, an optical device according to the present invention comprises a lens system for forming an image of an object and at least one light emitting unit for epi-illuminating the object. In this device, the light emitting unit illuminates an object through the outer portion of the optical path of the lens system and prevents the reflected light from the object passing through the central portion of the optical path of the lens system from interfering with the optical path of the lens system. It is characterized in that it is arranged in the outer part. According to this configuration, as described above, the light reflected from the object is not significantly obstructed by the light emitting unit, and the obtained image has sufficient brightness and good resolution. Furthermore, since the light emitting part is arranged in the optical path of the lens system, the most advanced lens on the objective side,
In particular, it is possible to make the objective surface small to accommodate the observation of a minute portion.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the epi-illumination method and optical device of the present invention will be described in more detail based on the embodiments shown in the accompanying drawings. With reference to FIG. 1, the optical device of this embodiment is indicated generally by the reference numeral 1 and comprises a lens system, in this embodiment a single lens 2, a lens frame 3 and an illuminator 4.

The lens 2 may be made of the same material, shape and size as those conventionally used for a rigid endoscope or the like. In this embodiment, the lens 2 has a substantially frustoconical shape with a flat objective surface 2a at the tip, and the image side surface 2b opposite to the objective surface is convexly curved. The objective surface 2a has a diameter of 1 mm, the image side surface 2b has a diameter of 6 mm, the curvature is R = 13.2 mm, and the lens length from the object surface to the image side surface is 12 mm.
This lens is designed to observe a range of about 0.4 mm. The side surface of the lens 2 is provided with an opaque coating that prevents light from entering and leaving.

Although the lens 2 has a conical shape in this embodiment, it may have another shape, for example, a polygonal pyramid.
The lens system in the optical device of the present invention is not limited to the single lens as in this embodiment, and it goes without saying that a plurality of lenses can be used in combination.

The lens frame 3 has a hollow truncated cone shape and is formed by machining an aluminum material. The tip portion of the lens frame 3 is adapted to support the lens end portion on the image side, and the lens 2 is adhered and fixed thereto.

The illuminator 4 has four light emitting portions or optical fibers 4a provided at equal intervals around the optical axis of the lens 2. The optical fiber 4a of this embodiment has a diameter of 1 mm. These light emitting parts are arranged on the outer side of the optical path of the lens system, and the optical path for the reflected light from the object is secured in the central part or the inner part of the lens system.

That is, in the present embodiment, the optical fibers 4a are arranged with their tip surfaces facing the outer portion of the image side surface 2b so as not to overlap the lens objective surface 2a when viewed in the optical axis direction of the lens. Grooves for receiving the respective optical fibers 4a are formed on the outer circumference of the lens frame 3, and each optical fiber 4a has its tip end faced to the outermost part of the image side surface 2b of the lens, and is fixedly adhered to the groove. The other ends of these optical fibers are connected to the light source 4b (FIG. 3) of the lighting fixture 4.

To carry out the epi-illumination method of the present invention using the optical device 1, the device is positioned so that the objective surface 2a of the lens is close to the object, and the illuminator 4 is turned on. Then, the illumination light is incident on the image side surface 2b of the lens from the tip of the optical fiber 4a, passes through the outer peripheral portion of the lens, and illuminates the object from the objective surface 2a. The reflected light from the object passes through the center of the lens in the direction opposite to the illumination light, and forms an image by the imaging optical system from the image side surface 2b. At this time, the reflected light passing through the central portion of the lens 2 is not obstructed by the light emitting portion of the illuminator 4, and an image with sufficient brightness and good resolution can be obtained.

The "outer side" means the side far from the optical axis of the lens, and the "inner side" means the side closer to the optical axis. The light emitting portion of the illuminator 4 is generally arranged within the outer one third of the distance from the optical axis of the lens to the farthest outer edge portion, in the case of the present embodiment, the radius of the image side surface 2b. Most preferred,
Depending on the shape and size of the lens, it may be within the outer half range. Further, it is most preferable that the light emitting portion is brought into contact with the image side surface of the lens in order to prevent loss of illumination light, but it may be installed apart from the lens surface if the illuminance can be secured by the size and number of the light emitting portions. .

Further, at least one light emitting portion of the illuminating device 4 is sufficient, but generally, at least one pair of light emitting portions are provided on both sides of the lens optical axis so as not to shade the illumination. It is preferable to provide them symmetrically. In the present embodiment, the light emitting unit is an optical fiber connected to the light source, but instead of this, a combination of a light emitting diode and a power supply wire may be used.

Next, another embodiment of the optical device according to the present invention will be described with reference to FIGS. In these figures, the same components as those of the optical device of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The illustrated embodiment is a rigid endoscope 10 that electronically visualizes an object to be observed. This rigid endoscope has a tip case 1
1, a tip case joint 12, a lens 2, a lens frame 3, a slide frame 13, a guide frame 15, a focus ring 16, a focus adjustment cylinder 17, a lens barrel 18, a C mount receiver 19, and a CCD imaging unit 20. The tip case, tip case joint, slide frame, guide frame, focus ring, focus adjustment tube, lens barrel, and C mount receiver are formed by machining an aluminum material, similar to the lens frame 3. Alternatively, these components may be molded of plastic material.

The tip case 11 is in the shape of a hollow cone that covers the lens frame 3, and has a hole 11a through which the optical fiber 4a passes, on the side thereof. The joint 12 is the tip case 1.
1 is a ring member for closing the rear opening. Tip case 1
1 and the joint 12 cover the end case 11 on the lens frame 3 of the lens device, and connect the optical fiber 4a to the hole 1 of the end case 11.
After being guided to the outside through 1a, male and female screws provided at both ends are engaged and coupled.

The guide frame 15 has a cylindrical shape, and a guide hole 15a elongated in the axial direction is formed in the side portion thereof. The guide frame 15 is coupled to the lens frame 3 and the lens barrel 18 via male screws formed on both ends thereof. The above-mentioned tip case joint 12 is fixed onto the end of the guide frame 15 using a set screw. Further, a CCD image pickup unit 20 is attached to the other end of the lens barrel 18 via a cylindrical C mount receiver 19. In this way, the tip case 11, the lens device 1,
Guide frame 15, lens barrel 18, and CCD imaging unit 2
0 are integrally assembled to form an optical path from the lens 2 to the CCD image pickup unit 20.

The slide frame 13 is a cylindrical member that can slide in the guide frame 15. A lens frame 13a is provided at an end of the slide frame 13 on the lens device side, and a second lens system for focus adjustment, a single lens 14 in this embodiment, is provided there.
Is attached. Also, on the side of the slide frame 13,
A guide pin 13b passing through the hole 15a of the guide frame is erected.

The focus ring 16 is a cylindrical member rotatable on the guide frame 15. At the side of the focus ring 16, an elongated guide hole 16a extending in an oblique circumferential direction is formed.
Is provided. The focus ring 16 is mounted on the guide frame 15 by passing the guide pin 13b of the slide frame through the guide hole 16a. When the focus ring 16 rotates, the tilted guide hole 16a moves the guide pin 13b of the slide frame by pushing or pulling along the guide hole 15a of the frame 15.

The focus adjusting cylinder 17 is a cylindrical member that can rotate on the lens barrel 18, and a focus screw 16 is provided by using a set screw.
Are bound to. Therefore, by turning the focus adjustment cylinder 17, the slide frame 13 moves toward the lens 2 or away from the lens via the focus ring 16 and the guide pin 13b, and the image forming position of the object is formed. Can be adjusted.

As shown in FIG. 3, the optical fiber 4a of the illuminator 4 is guided to the outside through the hole 11a of the tip case 11. A flexible protective cover 4c is mounted on these optical fibers.

In order to use the rigid mirror 10 thus constructed, as described above, the rigid mirror 10 is positioned so that the lens objective surface 2a is close to the object, and the object is illuminated by the illuminator 4. The reflected light from the object is reflected by the lenses 2 and 14
An image is formed on the CCD image pickup unit 20 through. At this time, the focus adjustment cylinder 17 is rotated to adjust the image forming position so that an appropriate image is output from the CCD image pickup unit 20. The image thus obtained has sufficient brightness and good resolution without being largely obstructed by the light emitting portion of the lighting fixture 4.

The optical device of the present invention may be used as an endoscope if a flexible optical fiber or the like is used in place of the CCD image pickup unit as a means for receiving an image in addition to the rigid endoscope described above. it can.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing an embodiment of an optical device according to the present invention.

FIG. 2 is an exploded perspective view showing another embodiment of the optical device according to the present invention.

FIG. 3 is a partial cross-sectional view showing the main parts of the optical device of FIG.

[Explanation of symbols]

1 Optical device 2 lenses 2b Image side 4a Optical fiber (light emitting part) 10 rigid endoscope (optical device) 20 CCD imaging unit

Claims (8)

[Claims] 1. In an epi-illumination method for illuminating an object substantially along a lens system for forming an image of the object, the illumination light is guided to the object through an outer portion of an optical path of the lens system, and reflected light from the object is reflected. , An epi-illumination method characterized by passing through the central part of the optical path of the lens system. 2. An optical device having a lens system for forming an image of an object and at least one light-emitting unit for epi-illuminating the object, wherein the light-emitting unit passes through an outer portion of an optical path of the object system. And an optical device which is arranged on the outer side of the optical path of the lens system so as not to interfere with reflected light from an object passing through the central part of the optical path of the lens system. 3. The optical device according to claim 2, wherein the light emitting unit is provided in contact with an image side surface of a lens of the lens system. 4. The optical device according to claim 3, wherein the light emitting portion is arranged outside half of a distance from an optical axis of the lens to an outer edge portion farthest from the optical axis. 5. The optical device according to claim 2, wherein the light emitting unit is an optical fiber connected to a light source. 6. The optical device according to claim 2, wherein at least two light emitting units are provided symmetrically with respect to the light beam of the lens system. 7. The optical device according to claim 2, further comprising means for receiving an image of an object, which is provided on the image side of the lens system. 8. The apparatus according to claim 7, wherein the means for receiving the image of the object is an electronic image pickup element and an image of the object movably provided between the element and the lens system. A second lens system for forming an image on the electronic image pickup device.