JPH11305141A - Enlarging image pickup device and optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and inexpensive enlarging image pickup device capable of preventing the generation of halation. SOLUTION: The enlarging image pickup device is provided with an image pickup element, an image forming lens 103a and plural light guiding means 106 for allowing illumination light L to exit from the periphery of the lens 103a to the front of the lens 103a. An annular light shielding part 12 for shielding light directed from the means 106 to a target W, regularly reflected by the target W and made incident upon the image pickup element through the lens 103a out of the illumination light L between the means 106 and the target, W is arranged on a position separated forward from the head surface of the means 106 and close to the optical axis of the lens 103a from the means 106.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnified image pickup apparatus for picking up an image of an object and displaying an enlarged image of the object on a monitor, and more particularly to an attachment mounted on a tip of the magnified image pickup apparatus.

[0002]

2. Description of the Related Art FIG. 4 shows a general example of this kind of enlarged image pickup apparatus. In FIG. 4, a case (casing) 100 has a cylindrical shape as a whole, and includes an imaging unit 102 that accommodates a CCD (imaging element) 101 and a lens unit (cylindrical body) 104 that accommodates a lens unit 103 for imaging. And the lens unit 10
4 is equipped with an illumination head 105. Case 1
At the rear end of 00, a bundle of optical fibers (light guide means) 106 is inserted. The optical fiber 106 is connected to the imaging unit 10.
2 are arranged annularly along the outer periphery of the lens portion 104 in FIG. 5 and substantially parallel to the optical axis Lc, so that an annular light beam is emitted from the distal end surface of the optical fiber 106. The illumination light L from the optical fiber 106 is reflected by, for example, a reflection surface 107 formed in the illumination head 105, and is emitted from the observation window 111 of the illumination head 105 toward the object W. Light L1 reflected from the object W
Is a CCD 101 via the lens unit 103 in FIG.
, And the image signal is output to a controller (not shown) of the monitor via the cable 108. The magnifying imaging apparatus obtains an annular luminous flux by arranging the optical fiber 106 in an annular shape around the outer periphery of the lens unit 104 so that, for example, a shadow is not generated on the surface of the object W.

The lens unit 104 is exchanged according to the object to be observed and the purpose of use. However, the lens unit 104 is used for observing a wide field of view at a low magnification or at a high magnification.
When the distance (working distance) from 3 to the object is long, when observing an object with high reflectance,
Halation appears. Therefore, conventionally, FIG.
The first and second reflecting mirrors 201 and 202 shown in FIG. 6 are attached to the lens unit 104, and the illumination light L is obliquely applied to the object W by the two reflecting mirrors 201 and 202 as shown in FIG. , The light that is specularly reflected by the object W is prevented from entering the objective lens 103a, thereby preventing halation from occurring. In this specification, “halation” refers to a phenomenon in which the amount of light is too large in an annular portion centered on the optical axis as compared with other portions, making it difficult to see an image, or the annular portion.

[0004]

However, in this prior art, since the outer diameter of the second reflecting mirror 202 becomes large, it is inevitable that the size of the illumination head of the magnifying imaging apparatus becomes large. Further, since a pair of reflecting mirrors 201 and 202 are used, the number of components increases, which causes an increase in cost.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a small-sized and inexpensive enlarged image pickup apparatus and an optical apparatus which can prevent the above-mentioned halation from occurring. It is.

[0006]

Next, prior to the description of the structure of the present invention, the principle of the present invention will be described. First, the cause of halation will be described. When the visual field A is wide as shown in FIG. 3A, as shown in FIG.
When the illumination light L emitted from the optical fiber 106 is specularly reflected on the surface of the object W, the specularly reflected light L1 enters the CCD (not shown) from the objective lens 103a, and thus halation occurs in the region Ah. Occurs.

[0007]

Therefore, in the first aspect of the present invention, as shown by a broken line in FIG.
03a through the light guide means 10
Light-shielding portion 1 that shields light in the optical path from object 6 to object W
2 are provided. By providing the light shielding portion 12, a part of the illumination light L emitted from the light guiding means 106,
In other words, by blocking the light L that causes halation indicated by the broken line, it is possible to prevent the light reflected specularly from the target object W from entering the image sensor through the lens 103a.
Therefore, no halation occurs.

On the other hand, the light shielding portion 12 is
At a position (hereinafter, referred to as a “front position”) away from the front end surface 106 a of the lens 103 a in the direction in which the illumination light L is emitted, and the optical axis L of the lens 103 a is larger than the light guide 106.
It is provided at a position close to c. Therefore, FIG.
As shown by the hatched portion in FIG. 2B, the field of view A is brightened by a part of the illumination light L from the light guiding means 106, so that an enlarged image can be viewed with a sufficient amount of light.

In the present invention, "specularly reflected by the object W" means that the object W is specularly reflected on a plane orthogonal to the optical axis Lc of the lens 103a. Further, the “field of view” refers to an imaging region when the focus determined by the shape, size, arrangement, characteristics, and the like of the imaging element and the lens is achieved. The “focused position” refers to a position where the image on the image sensor does not blur. Further, “shielding” means not only blocking light but also suppressing reflection of light, unlike a mirror or the like. Therefore, the light-shielding portion of the present invention does not include a mirror. Further, “the light shielding portion 12 is provided at a position closer to the optical axis Lc of the objective lens 103a than the light guiding means 106” means that the inner diameter φ1 of the annular light shielding portion 12 is larger than the inner diameter φ2 at which the light guiding means 106 is disposed. Also means smaller. Further, “annular” means that the window 13 through which the illumination light L passes is a perfect circle, and also includes a shape close to a circle such as an ellipse or a square. In addition, as the "light guide means", generally, one in which optical fibers are arranged on a circumference is employed.
Includes a light guide that guides light other than optical fiber.

On the other hand, an optical device according to a second aspect of the present invention is an optical device comprising: an imaging lens housed in a cylindrical body; and an illumination light from the periphery of the lens at the tip of the cylindrical body toward the front of the lens. And a light guide means for emitting light to an object, provided with a light-shielding ring for shielding a part of the illumination light emitted from the light-guide means, the light-shielding ring is provided on the cylindrical body A mounting portion for mounting, and a light-shielding portion that protrudes inward toward the optical axis side of the lens from the light-guiding unit and blocks the illumination light at a position in front of the distal end surface of the light-guiding unit, A window formed inside the light-shielding portion and allowing illumination light to pass therethrough.

[0011] An enlarged image pickup apparatus according to the present invention generally comprises:
Since a lens unit accommodating a lens is attached to an image pickup unit accommodating an image pickup device, and an optical device in which a light-blocking ring is attached to the lens unit is used as a unit, a commercial transaction is performed. Claim 4 is provided so that the scope of the right can be defined with the light-shielding ring attached.

In the present invention, "from the periphery of the lens" means that the light guide means 106 is disposed in a substantially annular shape around the lens 103a in FIG. 2B. As described above, since the light guide 106 emits the illumination light L from around the lens 103, the entire field of view A can be brightly illuminated even if the light shielding portion 12 is provided.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an optical device of the present invention. The basic structure of the magnified imaging apparatus is the same as that of the conventional example shown in FIG. 4, and therefore, different parts will be mainly described. FIG.
In the optical device, the lens unit 104 and the light shielding ring 1
0. The lens portion 104 is a cylindrical body having a female screw 20 and a male screw 21 at upper and lower ends. The lens unit 104 is attached to the imaging unit 102 by screwing the female screw 20 into a male screw (not shown) of the imaging unit 102 in FIG. The optical fiber 106 shown in FIG. 1 has an objective lens 103a (FIG. 2) at the tip of the lens unit 104.
The illumination light L emitted from the optical fiber 106 is substantially parallel to the optical axis Lc of the lens unit 103 at a predetermined solid angle. Is emitted.

A female thread (mounting portion) 11 of the light-shielding ring 10 is screwed into the male screw 21 of the lens portion 104, and the light-shielding ring 10 is mounted on the lens portion 104. The light-shielding ring 10 is provided on the distal end surface 1 of the optical fiber 106.
A light-shielding portion 12 protruding inward toward the optical axis Lc side of the lens unit 103 from the optical fiber 106 ahead of the optical fiber 106 a is formed integrally with the female screw portion 11. The light-shielding part 12 shields a part of the light L indicated by a broken line from the illumination light L emitted from the optical fiber 106 at a predetermined solid angle. Coated with a small matte coating. The optical axis Lc and the object W
A substantially circular window 13 is formed to pass the reflected light L1 from the camera.

The magnified image pickup apparatus is for observing a wide field of view at a low magnification, for example. Therefore, when the light-shielding ring 10 is not provided, as shown by a broken line in FIG. At the matching position, the area Ah causing halation is set to be included in the visual field A. On the other hand, in the present enlarged imaging apparatus, since the light-blocking ring 10 is provided, as shown by a broken line in FIG.
Since the light L that causes halation is blocked, halation can be prevented. The area Ah where halation occurs is an area in the object W where the illumination light L is regularly reflected and is incident on the CCD 101 from the lens unit 103 at a focused position when the light-shielding ring 10 is not provided. .

Further, the above-mentioned halation can be prevented by merely attaching one light-shielding ring 10 to the lens portion 104, so that the number of parts is reduced and the cost can be reduced. Further, the light-shielding ring 10 is the second reflection mirror 20 shown in FIG.
Since the outer diameter can be reduced as compared with 2, the size of the optical device can be reduced.

In FIG. 2B, the inner diameter (outer diameter of the window 13) of the light-shielding portion 12 of the light-shielding ring 10 is determined by the boundary of the area illuminated by the illumination light L from one optical fiber 106 with the optical axis Lc. It is preferable to make them substantially coincide with each other because unevenness in the amount of light does not occur. However, in the present invention, the inner diameter φ1 of the light shielding portion 12 may be slightly larger or smaller than the state shown in FIG. Alternatively, the distance D from the tip of the optical fiber 106 to the inner surface 14 of the light shielding unit 12 may be set slightly larger or smaller than the state shown in FIG.

In this embodiment, only the optical fiber 106 is used as the light guiding means, but an illumination lens or the like may be provided at the tip of the optical fiber 106 in addition to the optical fiber 106.

[0019]

As described above, according to the present invention,
Since the light-shielding portion is provided in front of the front end surface of the light guide means, it is possible to prevent halation by blocking the illumination light from the light guide means, to reduce the number of parts and to reduce the cost, and to achieve a reflection mirror. The size of the magnified image pickup device and the optical device is reduced as compared with the case of using.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical device showing one embodiment of the present invention.

FIG. 2 is a conceptual diagram of an optical device illustrating the principle of the present invention.

FIG. 3 is a conceptual diagram of an optical device for explaining a cause of halation.

FIG. 4 is a side view showing a general magnified imaging device.

FIG. 5 is a sectional view of a general illumination head.

FIG. 6 is a perspective view and a sectional view of a conventional optical device.

[Explanation of symbols]

 10: light-shielding ring 11: female screw part 12: light-shielding part 13: window 101: CCD (imaging device) 103: lens unit 104: lens unit (tubular body) 106: optical fiber (light guide means) L: illumination light L1 : Reflected light Lc: Optical axis

Claims (5)

[Claims] 1. An enlarged image pickup apparatus in which an image pickup device, an image forming lens, and light guiding means for emitting illumination light from a periphery of the lens toward the front of the lens to an object are accommodated in a cylindrical housing. In the apparatus, of the illumination light, light that is specularly reflected by the target object from the light guide unit and is incident on the image pickup device through the lens, in an optical path from the light guide unit to the target object. An annular light-shielding portion for shielding light is provided, and the light-shielding portion is located at a position separated in a direction in which the illumination light is emitted from the distal end surface of the light guide means, and is provided with light of the lens more than the light guide means. An enlarged image pickup apparatus, which is provided at a position close to an axis. 2. An enlarged image pickup apparatus in which an image pickup device and a lens for imaging are housed in a cylindrical housing, and light guide means for emitting illumination light from a periphery of the lens to a front of the lens toward an object. An apparatus, wherein an area that causes halation at a focused position is set to be present in the field of view, and illumination light that causes halation among the illumination light is
An annular light-shielding portion that shields light in an optical path from the light-guiding unit to the target is provided, and the light-shielding unit is located at a position separated in a direction in which illumination light is emitted from a distal end surface of the light-guiding unit, and An enlarged image pickup apparatus, wherein the apparatus is provided at a position closer to an optical axis of the lens than the light guide unit. 3. The magnified image pickup device according to claim 1, wherein the light guide means includes a plurality of optical fibers disposed on a circumference of the lens at a tip of the cylindrical housing. . 4. An imaging lens housed in a cylindrical body, and light guide means for emitting illumination light to an object from the periphery of the lens at the tip of the cylindrical body to the front of the lens. An optical device, comprising: a light-shielding ring that shields a part of the illumination light emitted from the light-guiding means, wherein the light-shielding ring is attached to the cylindrical body, and At a position separated in the direction in which the illumination light is emitted from the distal end surface of the light guide means, an annular light shielding portion that projects inward toward the optical axis side of the lens from the light guide means and shields the illumination light, An optical device comprising: a window formed inside the light-shielding portion to allow illumination light to pass therethrough. 5. The optical device according to claim 4, wherein the light guiding means is composed of a plurality of optical fibers disposed on the circumference of the lens at the tip of the cylindrical body.