JP2000292703A - Confocal optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a confocal optical device which is compact and whose inserting direction is aligned with a visual field direction. SOLUTION: This device is provided with a light source 1 irradiating a surface 7 to be detected with light, a scanning part 4 scanning the surface 7 to be detected with the light, a condensing optical system 407 condensing the light from the part 4 on the surface 7, and a light detecting part 3 detecting returning light from the part 4. The part 4 is provided with an optical scanning mirror 406 having a pin hole 6, and the system 407 includes a reflecting surface 407a reflecting the light from the mirror 406 and a lens having negative refracting power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a confocal optical device having a light condensing portion for irradiating a test object with light from a light source and focusing the object, and in particular, to observe the inside of a human body with high resolution. The present invention relates to an optical scanning type confocal endoscope that can perform the operation.

[0002]

2. Description of the Related Art In recent years, a light-scanning confocal microscope has been known as a means for observing the surface or inside of a living tissue or cell at a high resolution. The confocal optical system has a feature that it has a resolution exceeding the resolution limit of a normal optical system and can construct a three-dimensional image. However, with a normal confocal microscope, the size of the optical system is so large that it is difficult to insert it into the body. Therefore, a method of taking out a living tissue outside the body and observing it is known.

An example of a compact confocal optical system is “Micomachined scanning confocal optical mimi”.
croscope ”OPTIC LETTERS Vol.21 No.10 May.1996
Is known. FIG. 8 shows an example of a conventional optical scanning confocal microscope, in which 1 is a light source, 2 is a light transmission unit, 3 is a light detection unit,
Reference numeral 4 denotes an optical scanning unit, and reference numeral 5 denotes an image processing unit. The optical transmission unit 2 is made of a single mode fiber, and shows a possibility that a three-dimensional image of a living body can be observed in real time by inserting the present microscope into a body endoscopically.

FIG. 9 shows the details of the optical scanning section 4. In the figure, 201 is an optical transmission fiber, 401 is a reflecting surface, 4
Numerals 02 and 403 denote electrostatic mirrors for scanning in the X and Y directions, 404 a reflection unit, 405 a diffraction lens, and 7 a surface to be measured. Light transmitted from the light source 1 via the optical transmission fiber (single mode fiber) 201 is sequentially reflected by the reflection surface 401, the electrostatic mirror 402, the reflection section 404, and the electrostatic mirror 403, and is transmitted through the diffraction lens 405. The light is condensed on the test surface 7. The reflected light from the converging point on the surface 7 to be measured is diffracted by the diffraction lens 405, the electrostatic mirror 403, and the reflection unit 4.
The light is transmitted via the optical transmission fiber 04, the electrostatic mirror 402, and the reflection surface 401, enters the optical transmission fiber 201, and is detected by the light detection unit 3 on the hand side.

In this configuration, the optical transmission fiber 201
Has a configuration that also serves as a confocal pinhole,
The intensity of scattered light from other than the focal point is extremely weak at the end face of the fiber, and is hardly detected by the detector. Since this optical system is a confocal system and can not only obtain a high resolution due to the square characteristic, but also has a resolution in the depth direction (Z-axis direction) that does not exist with the existing optical system, it is possible to obtain three-dimensional information of a living tissue. Can be obtained with high resolution. Also, this conventional example,
Although it does not have the resolution of an ordinary confocal optical microscope, it is compact while maintaining sufficient resolution for diagnosis.

[0006]

However, in the above conventional example, the surface to be measured is inclined with respect to the longitudinal direction of the fiber.
When considering radial endoscopic insertion, there is a problem that the direction of insertion of the scope and the direction of view are different.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a confocal optical device which is compact and whose insertion direction matches the viewing direction. Is to do.

It is another object of the present invention to provide a confocal optical device having a confocal optical system in which aberrations such as curvature of field and coma generated during scanning are well corrected.

[0009]

In order to achieve the above object, a confocal optical device according to the present invention comprises a light source for irradiating light to an object to be inspected, and a light source for scanning light on the object to be inspected. A scanning unit, a condensing optical system that collects light from the scanning unit on the target, and a confocal optical device including a light detection unit for detecting return light from the scanning unit. The scanning unit includes a reflecting surface having a minute opening, and the light-collecting optical system includes a reflecting surface that reflects light from the scanning unit and at least one surface having a negative refractive power. Features.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is an overall configuration diagram of an embodiment of a confocal optical device according to the present invention, and FIG. 2 is a front view of an optical scanning mirror. In FIG. 1, 1 is a light source such as a laser, 2 is an optical transmission unit, 3 is a light detection unit, 4 is an optical scanning unit, 5 is an image processing unit, 6 is a pinhole (opening), and 7 is a surface to be measured. is there. The light transmission unit 2 includes a light transmission fiber 201 for transmitting light from the light source 1 to the light scanning unit 4 and a four-terminal coupler 202 for light branching. An optical scanning mirror 406 having
It comprises a condensing optical system 407 and a stop 408 for preventing unnecessary light.

As shown in FIG. 2, an optical scanning mirror 406
Is an electrode 4 for driving an inner hatched portion serving as a mirror surface.
06a and 406b, electrodes 406c and 406d for driving an outer hatched portion forming an outer frame, and electrodes 406a and 406d.
Hinge portions 406e, 406c, 406c, and 406d, each of which can support and rotate around the respective supporting direction.
406f, 406g and 406h. 8
a, 8b, 8c, 8d are the respective electrodes 406a, 406b, 4
This is a wiring for supplying a voltage to 06c and 406d.
A ground plane is formed at a predetermined interval below each electrode, and a voltage is applied between each electrode and the ground plane by each of the wirings 8a, 8b, 8c, and 8d, so that the electrode-ground plane is formed. An electrostatic attraction is generated between the surfaces,
Light incident on the electrodes 406a and 406b serving as mirror surfaces can be two-dimensionally deflected.

The scanning mirror 406 has a gimbal structure and can be manufactured by a micro-machining technique using a semiconductor manufacturing technique. In this method, silicon is used as a constituent member, aluminum is used for electrodes and wires, and a hinge portion is formed of a silicon nitride film. In manufacturing, first, a silicon nitride film is deposited on a silicon member and patterned into a gimbal shape. Next, a metal film for an electrode is formed to form a wiring and an electrode. Lastly, the silicon member is processed into a gimbal structure. In this processing, a wet etchant is used, and a silicon nitride film is used as a mask material at this time. At this time, the metal constituting the electrode and the electric wire is also exposed to the etchant, so that the metal to be used must be selected to have resistance to the wet etchant. Further, since this processing is isotropic, the hinge portion after the processing becomes only the silicon nitride film, and can be rotated. Note that the diameter of the pinhole 6 is １ ／ of the diffraction limit diameter in order to function as a confocal pinhole.
The following is desirable, but S / N may be emphasized and may be expanded to the diffraction limit.

Since the present embodiment is configured as described above, the light emitted from the light source 1 is
After being incident on one incident end 201a, the light is branched by the four-terminal coupler 202 and reaches the exit end 201b. Thus, the light that has reached the light scanning unit 4 is transmitted to the light scanning mirror 406 and the condenser lens 40.
The light is condensed on the surface 7 to be detected by the light 7 and scanned. Here, the pinhole 6 is given an opening diameter that functions as a confocal pinhole. That is, the light diffracted on the surface of the pinhole 6 of the optical scanning mirror 406 is reflected by the reflecting surface 407 a of the condenser lens 407 and enters the optical scanning mirror 406.
This reflected light is incident on the condenser lens 407 again, and
Focus on top. The scattered light from the focal position on the test surface 7 returns along the same path as the incident light, passes through the pinhole 6, enters the optical transmission fiber 201 from the emission end 201b, and is branched by the four-terminal coupler 202. Outgoing end 2
01c, the light enters the light detection unit 3 and is detected. The scattered light detected in this way is processed by the image processing unit 5 to form an image. On the other hand, scattered light from a position other than the focal position on the surface 7 to be detected hardly passes through the pinhole 6 and therefore has little intensity in the light detection unit 3 and is not detected.

In this case, if the light used is a single wavelength, the condensing optical system 407 can be composed of a single lens using an aspherical surface, which is preferable in terms of configuration and assembly. Since the undulation and surface roughness adversely affect the resolution of the optical system, if high resolution is required, it is a good idea to use a plurality of spherical lenses that easily provide high surface accuracy and are easy to manufacture. It is. However, when a spherical lens is used, it is necessary to arrange a surface (concave surface) of negative power in the condensing optical system in order to correct spherical aberration, field curvature and coma generated during scanning. .

As described above, if the aperture diameter of the pinhole 6 is set to about the diffraction limit, the function as a confocal pinhole can be provided, and the pinhole suitable for resolution and S / N can be set. In addition, the assemblability can be improved.
Further, by using a two-dimensional scanning mirror as the reflection surface having the pinhole 6, it is possible to reduce the number of components and to reduce the diameter of the optical system. The reflection surface to the scanning mirror 406 has a good S /
In order to secure N, a convex shape is desirable. Since this reflecting surface is disposed on the first surface of the lens constituting the light collecting optical system 407, flare and the like are suppressed, and the optical system can be simplified.

The simplest configuration for realizing a confocal optical system as a connection method between the light transmission unit 2 and the light scanning unit 4 is a method using a single mode fiber. In this case, the exit end 201b of the single mode fiber is guided to the vicinity of the optical scanning mirror 406, and the core can be a confocal pinhole. In addition, the effect of a confocal pinhole may be provided by placing the pinhole 6 on the image plane, but in this case, a confocal pinhole having an appropriate diameter can be provided. There are advantages. In this case, the efficiency can be improved by using the optical transmission unit 2 as a multi-mode fiber. However, the exit end of the fiber and the pinhole must be sufficiently close. If it is difficult to make the pinhole and the fiber exit end sufficiently close in space, a condensing lens may be provided between the pinhole and the fiber exit end.

In order to exert the confocal effect, the optical system needs to be aberration-corrected to near the diffraction limit.
The light reflected by the scanning mirror 406 is incident on a condenser lens having a reflective film.
When 06 is inclined, the condensing optical system 407 is decentered with respect to the incident light. Therefore, on a convex surface having a reflective film, the incident angle with respect to the lens differs greatly between the upper subordinate ray and the lower subordinate ray, and a large outer coma aberration occurs. In order to cancel the external coma aberration, the surface 407 on which the reflective film is formed is used.
It is necessary to generate the inner coma aberration by setting the opposing surface of a to negative power. Specifically, when the radius of curvature of the surface on which the reflective film is formed is R1, the radius of curvature of the facing surface is R2, and the focal length is f, 0 ≦ R1 / f ≦ 20, −10 ≦
It is desirable to satisfy the relationship of R2 / f ≦ 10. However, when the area of the reflective film is reduced to improve S / N, 0 ≦ R1 / f ≦ 10, −5 ≦ R2 / f ≦
It is desirable to satisfy the relationship of 5. In addition,
Here, although the signs of R1 and R2 are positive or negative, the case where the lens surface is convex toward the optical scanning mirror 406 is defined as positive.

The reflected light from the light scanning mirror 406 re-enters the condensing optical system 407, but the light incident on the reflecting surface 407a becomes unnecessary light, and is multiply reflected between the light scanning mirror and the condensing optical system. , And stray light. Therefore, it is possible to increase the convex power of the reflecting surface 407a and obtain an image with a better S / N as the diameter of the reflecting surface is smaller than the diameter of the light beam transmitted through the condensing optical system. On the other hand, if the power of the reflecting surface 407a is made unnecessarily large, the ray height becomes high when the light scanning mirror 406 is tilted at the time of incidence on the light collecting optical system 407.
As a result, the optical scanning mirror must be large, and directly affects the driving voltage. Optical scanning mirror 40
Assuming that the distance from L6 to the condensing optical system 407 is L, the light beam diameter D1 on the reflecting surface 407a is L × θ, and the condensing optical system 407
The diameter D2 of the luminous flux passing through is L × θ + 2 × L × (θ + 2 × L
× θ / R1). Here, sin θ is the numerical aperture on the pinhole 6 side. D1 / D2 = 1 / (2 × (1 + 2 × L
/ R1) +1), from the viewpoint of suppressing S / N, D1 / D2
It is desirable that ≦ 0.25. On the other hand, the luminous flux diameter in the light scanning unit 4 is 2 × L × θ, where θ is the pinhole exit angle.
× (1 + L / R1), but 2 × L × θ × (1 + L /
It is desirable to satisfy the relationship of R1) ≦ 1.0 mm. Therefore, R1 is 2 × L ² × θ / (1-2 × θ × L) ≦ R
It is desirable to satisfy the relationship of 1 ≦ 4 × L.

In general, when performing cytodiagnosis, a resolution of about 1 μm is required, so that the object side numerical aperture of the lens is required to be 0.2 or more. In particular, when high resolution with a numerical aperture of 0.3 or more is required, it is desirable that the first surface of the condensing optical system 407 from the surface 7 to be inspected has a concave shape in order to reduce spherical aberration. However, since the first surface is also an outer surface, it is also desirable that the first surface be a flat surface for the purpose of preventing attached matter. Therefore, it is effective to make the first surface a flat surface in order to achieve compactness.

In order to ensure a good S / N ratio, the reflection surface 407a for the diameter of the light beam transmitted through the condensing optical system 407 is required.
Is preferably 0.3 or less, and the ratio of the diameter of the reflecting surface 407a to the outer diameter of the lens forming the light-collecting optical system is preferably 0.15 or less. On the other hand, an increase in the size of the optical scanning mirror 406 causes an increase in driving voltage and is not preferable for use in the human body. Therefore, the range of the reflection area of the optical scanning mirror 406 is suppressed to 1.5 mm or less, and the optical scanning Is desirably driven. Condensing optical system 407
Considering the insertion of the device into the endoscope channel, it is desirable that the outside diameter be 3.0 mm or less, while the outside diameter is D, and the distance from the final surface of the lens to the focal point is W
D, when the object-side numerical aperture of the lens is NA, D ≧ 2 × W
A relationship of D × NA is required, and considering mirror scanning, it is desirable to satisfy the relationship of D ≧ 2 × WD × NA + 0.5 mm. Also, considering its application to cytology,
Since it is desired to obtain information inside a tissue of 1 mm or more, the WD needs to be 1 mm or more. The resolution of the confocal microscope is determined by the NA of the condenser lens and the wavelength of the observation light. To secure a resolution of 1 μm,
The object side numerical aperture of the condenser lens needs to be 0.20 or more. Therefore, in this optical device, the required resolution and WD
In order to secure the lens diameter, the lens outer diameter of the condensing optical system 407 must be 1.
It needs to be 0 mm or more.

Although the case of observation using a monochromatic laser beam has been described above, it goes without saying that the present optical device can also be applied to observation using light of a plurality of wavelengths, such as fluorescence observation.
Generally, when observing a living tissue, a mucous membrane, or the like, fluorescence observation is performed after a fluorescent substance is injected into a test object in advance. In the case of such fluorescence observation, the difference in the wavelength between the illumination light and the detection light causes the return light to converge on the axis and in the magnification direction. If this shift amount is larger than the pinhole diameter,
Since information on the surface to be inspected is buried in noise and the resolution is consequently reduced, in this case, a focus shift due to wavelength can be reduced by a method such as using a cemented lens. or,
In order to selectively observe only the abnormal part of the cell, there is a method that utilizes the difference in the optical characteristics between the normal part and the abnormal part of the cell.In this case, a dichroic light that separates the wavelength of the illumination light and the fluorescence is used. Mic mirror etc. are arranged in front of the detection system, and PD (photodiode) is applied to each of the separated fluorescence and normal light.
And observation is performed (see FIG. 10).

The present optical device can be used as a compact direct-view confocal microscope or the like that can be inserted into the body by being configured as described in detail above. Various embodiments 407 will be described.

FIG. 3 is a sectional view showing the first embodiment.
(A) shows the state of the light beam when the light scanning mirror 406 is perpendicular to the optical axis, and (b) shows the state of the light beam when the light scanning mirror 406 is inclined by 3 ° in the XY directions. In this embodiment, an optical system suitable for a specification of a resolution of 1 to 5 μm is used.
It is composed of two lenses. Lenses 407b and 40
7c are arranged such that the concave surfaces face each other, and the first
0.2 mm in diameter at the center of the convex surface of lens 407b
Is provided by vapor deposition. Aluminum or gold is used for vapor deposition. The reflection surface may be removed from the center of the vapor deposition section in order to prevent the S / N ratio from being reduced due to light directly reflected on the pinhole 6.

The light beam incident on the pinhole 6 as described above is reflected on the reflection surface 407 a and is incident on the optical scanning mirror 406. This reflected light is incident on the condensing optical system 407 again and is condensed on the surface 7 to be measured. The scattered light from the focal position of the test surface returns on the same path as the emitted light, passes through the pinhole 6, enters the emission end 201b of the optical transmission fiber 201, reaches the emission end 201c via the four-terminal coupler 202, and is detected. It is detected by the unit 3. On the other hand, the scattered light from other than the focal position hardly passes through the pinhole 6, so that the detection unit 3 has little intensity and is not detected. The condensing optical system 407 is an optical system having a desired resolution up to the periphery of a 600 μm field of view, and the lens data is shown below. r1 = ∞ (optical scanning mirror 406) d1 = 2.96 r2 = 12.66 d2 = 1.00 n2 = 1.51463 v2 = 64.14 r3 = 3.28 d3 = 0.53 r4 = -12.69 d4 = 1.00 n4 = 1.87852 .nu.4 = 40.76 r5 = -4.51 d5 = 0.20 r6 = 4.10 d6 = 1.10 n6 = 1.87852 .nu.6 = 40.76 r7 = -17 .81 d7 = 4.29 r8 = ∞ (test surface 7) FIG. 4 shows a second embodiment of the light-converging optical system 407. This embodiment is basically a lens system similar to that of the first embodiment, except that the radius of curvature of the first surface 407e is 3.5 mm, which is smaller than the focal length, and the incident light is incident on the reflection surface 407a. In that the luminous flux of the lens was increased and the S / N ratio was improved.
This is different from the first embodiment. The diameter of the reflection surface 407a is 150
μm, and the lens data is shown below. r1 = ∞ (optical scanning mirror 406) d1 = 2.10 r2 = 3.50 d2 = 1.00 n2 = 1.51463 v2 = 64.14 r3 = 2.81 d3 = 0.56 r4 = -7.39 d4 = 1.00 n4 = 1.88522 v4 = 40.76 r5 = -3.80 d5 = 0.21 r6 = 4.96 d6 = 1.10 n6 = 1.87852 v6 = 40.76 r7 = -15 0.75 d7 = 4.95 r8 = ∞ (surface 7 to be inspected) FIG. 5 shows a third embodiment of the light collecting optical system 407. This embodiment is a lens system aiming for a high numerical aperture.
It has an object plane resolution of 2 μm. In addition, the radius of curvature of the first surface 407f is set to 10 mm with respect to the focal length of 1 mm, and emphasis is placed on ensuring the visual field range. The lens data is shown below. r1 = ∞ (optical scanning mirror 406) d1 = 1.95 r2 = 10.00 d2 = 1.00 n2 = 1.51463 v2 = 64.14 r3 = 2.19 d3 = 0.50 r4 = 18.13 d4 = 1.00 n4 = 1.87852 ν4 = 40.76 r5 = −3.43 d5 = 0.20 r6 = 2.45 d6 = 1.10 n6 = 1.87852 ν6 = 40.76 r7 = 324.78 d7 = 1.99 r8 = ∞ (surface 7 to be inspected) FIG. 6 shows a fourth embodiment of the light collecting optical system 407. In this embodiment, the S / N is improved in the third embodiment. The radius of curvature of the first surface 407g is set to 3 mm, and the diameter of the reflection surface 407a is suppressed to be small with respect to the incident light beam. The diameter of the reflection surface 407a is 140 μm, and the final surface 407h of the light-converging optical system 407 is a flat surface.
Hereinafter, the lens data will be shown. r1 = ∞ (optical scanning mirror 406) d1 = 2.19 r2 = 3.00 d2 = 1.00 n2 = 1.51463 v2 = 64.14 r3 = 1.94 d3 = 0.50 r4 = 22.96 d4 = 1.00 n4 = 1.87852 ν4 = 40.76 r5 = −3.71 d5 = 0.20 r6 = 2.31 d6 = 1.10 n6 = 1.87852 ν6 = 40.76 r7 = ∞ d7 = 1.74 r8 = ∞ (surface 7 to be inspected) FIG. 7 shows a fifth embodiment of the light-converging optical system 407. This embodiment is intended to further increase the numerical aperture, is composed of four lenses, and has an object plane resolution of 1 μm or less. Although the final surface 407i of the condensing optical system is a concave surface to correct spherical aberration, it may be configured to be a flat surface and also serve as a cover glass. Hereinafter, the lens data will be shown. r1 = ∞ (optical scanning mirror 406) d1 = 1.68 r2 = 8.00 d2 = 1.00 n2 = 1.51463 v2 = 64.14 r3 = 2.05 d3 = 0.50 r4 = 106.71 d4 = 0.90 n4 = 1.87852 ν4 = 40.76 r5 = −4.64 d5 = 0.20 r6 = 5.05 d6 = 0.90 n6 = 1.87852 ν6 = 40.76 r7 = −16. 00 d7 = 0.20 r8 = 1.98 d8 = 1.30 n8 = 1.87852 ν8 = 40.76 r9 = 9.05 d9 = 1.10 r10 = ｒ (surface 7 to be inspected) , R 1, r 2,... Are the radii of curvature of the respective surfaces of the lenses, etc., d 1, d 2,. Wavelength) = refractive index of each lens for 633 nm, ν1, ν
,... Are the Abbe numbers of each lens with respect to λ = 633.

As described above, the confocal optical device of the present invention has the following features. (1) A light source for irradiating light to a test portion, a scanning portion for scanning light on the test portion, and a light condensing device for condensing light from the scanning portion on the test portion. In a confocal optical device including an optical system and a light detection unit for detecting return light from the test portion, the light scanning unit includes a reflection surface having a minute opening, and the light collection optical system Is a confocal optical device comprising: a reflecting surface for reflecting light from the light scanning unit; and at least one surface having a negative refractive power.

(2) In the scanning section, the reflection surface is arranged at or near a position conjugate with the test section, and the size of the opening is set to a diffraction limit or smaller. The optical device according to (1), wherein

Thus, the aperture can function as a confocal pinhole, so that the pinhole suitable for the resolution and S / N can be set and the assemblability can be improved. (3) The optical device according to (1) or (2) above, wherein at least one of the reflection surfaces of the light scanning unit and the light-converging optical system includes a scanning mirror capable of one-dimensional scanning.

(4) Any one of the light scanning section and the reflection surface of the light-collecting optical system is composed of a scanning mirror capable of secondarily scanning light from a light source in a direction orthogonal to each other. The optical device according to (2).

As a result, the number of parts can be reduced and the diameter of the optical system can be reduced. (5) The optical device according to (4), wherein the scanning mirror has a gimbal structure.

Thus, angular motion in two directions can be given to the reflecting surface by two rotation axes orthogonal to each other. (6) The optical device according to any one of (1) to (5), wherein one of the reflection surface of the light scanning unit and the light-collecting optical system is a convex mirror.

As a result, it is possible to secure a large luminous flux at the position of the reflection surface of the reflected light from the scanning mirror, and it is possible to secure a good S / N. (7) The optical device according to (6), wherein the convex mirror is a reflection film formed on a lens surface of the condensing optical system.

Thus, flare and the like can be suppressed, and the optical system can be simplified. (8) The optical device according to (1), wherein a scanning mechanism for scanning light on the surface to be inspected is provided on the reflection surface having the opening.

(9) The optical device according to any one of (1) to (8), wherein an optical fiber is used as means for transmitting light from the light source to the optical scanning unit. (10) The optical device according to (9), wherein the optical fiber is a single mode fiber.

Thus, a confocal optical system having the simplest configuration can be realized. (11) The end face of the single mode fiber is positioned near the mirror having the aperture so as to form a confocal pinhole.
An optical device according to claim 1.

(12) The optical device according to (10), wherein the single mode fiber is connected to a mirror having the opening, and the mirror opening becomes a confocal pinhole.

(13) The optical device according to (9), wherein the optical fiber is a multimode fiber. Thereby, the efficiency of the confocal optical system can be improved.

(14) The optical device according to the above (13), wherein a condenser lens is arranged between the optical scanning section and the optical fiber. This makes it possible to provide an efficient confocal optical device even when it is difficult to make the pinhole and the fiber end face sufficiently close to each other in terms of space.

(15) The optical device according to the above (7), wherein the reflection film is formed on the first surface from the image forming surface side of the condensing optical system. (16) The optical device according to (8), wherein the size of the reflecting surface having the opening having the scanning mechanism is 1.5 mm or less.

(17) The optical apparatus according to any one of (1) to (16), wherein the first lens surface of the converging optical system from the test portion has no power or negative power. (18) The optical device according to (15), wherein in the lens having the reflective film, a surface facing the surface on which the reflective film is formed has negative power.

(19) When the radius of curvature of the surface on which the reflective film is formed is R1, the radius of curvature of the surface facing the surface on which the reflective film is formed is R2, and the combined focal length of the light-converging optical system is f. The optical device according to the above (18), wherein the following relationship is satisfied: 0 ≦ R1 / f ≦ 20, −10 ≦ R2 / f ≦ 10.

(20) When the radius of curvature of the surface on which the reflective film is formed is R1, the radius of curvature of the surface facing the surface on which the reflective film is formed is R2, and the combined focal length of the light-collecting optical system is f. The optical device according to (18), wherein the following relationship is satisfied: 0 ≦ R1 / f ≦ 10, −5 ≦ R2 / f ≦ 5.

As a result, the deposition range of the reflection film can be reduced, and the S / N can be improved. (21) The optical device according to (18), wherein the ratio of the diameter of the reflection film to the outer diameter of the lens of the light collection optical system is 0.15 or less.

As a result, good S / N can be secured. (22) The light detection unit includes a wavelength separation element that separates illumination light emitted from a light source to the target unit and fluorescence generated from the target unit when the target unit is illuminated with the illumination light. The optical device according to any one of (1) to (21), further including an optical element for detecting the illumination light and the fluorescence.

[0044]

As described above, according to the present invention, it is possible to provide a compact, high-resolution, confocal optical device that can be directly viewed with sufficient aberration corrected.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a confocal optical device according to the present invention.

FIG. 2 is a front view of an optical scanning mirror.

FIG. 3 is a cross-sectional view showing a first embodiment of a light collecting optical system;
(A) shows the state of the light beam when the optical scanning mirror is perpendicular to the optical axis, and (b) shows the state of the light beam when the scanning mirror is inclined by 3 ° in the XY directions.

FIG. 4 is a sectional view showing a second embodiment of the light collecting optical system.

FIG. 5 is a sectional view showing a third embodiment of the light collecting optical system.

FIG. 6 is a sectional view showing a fourth embodiment of the light collecting optical system.

FIG. 7 is a sectional view showing a fifth embodiment of the light collecting optical system.

FIG. 8 is an overall configuration diagram of an example of a conventional scanning confocal microscope.

FIG. 9 is a detailed view of an optical scanning unit used in the conventional example shown in FIG.

FIG. 10 is a diagram showing a schematic configuration of a dichroic mirror.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 light source 2 light transmission unit 201 light transmission fiber 202 light branching four-terminal coupler 3 light detection unit 4 light scanning unit 401 reflecting surface 402,403 electrostatic mirror 404 reflecting unit 405 diffraction lens 406 light scanning mirror 406a, 406b, 406c , 406d Electrodes 406e, 406f, 406g, 406h Hinge 407 Condensing optical system 407a Reflecting surface 407b, 407c, 407d Lens 407e, 407f, 407g, 407h, 407i
Lens surface 408 Unnecessary light prevention aperture 5 Image processing unit 6 Confocal pinhole 7 Surface 8a, 8b, 8c, 8d Wiring

Claims (1)

[Claims] 1. A light source for irradiating light to a test portion, a scanning portion for scanning light on the test portion, and condensing light from the scan portion on the test portion. In a confocal optical device including a condensing optical system and a light detection unit for detecting return light from the test section, the light scanning unit includes a reflection surface having a minute opening, A confocal optical device, wherein the optical system includes a reflecting surface that reflects light from the optical scanning unit and at least one surface having a negative refractive power.