JP2002107597A - Lens barrel and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the resolution (SN ratio) of an image by restraining reflection on an inner peripheral surface. SOLUTION: This method includes a metallic cylinder manufacturing step 15 manufacturing a metallic cylinder 1 in which a lens is assembled, plating steps 16 and 17 plating the inner peripheral surface of the cylinder 1 manufactured in step 15 with a nickel-phosphorus alloy so as to form a nickel- phosphorus alloy film on the inner peripheral surface thereof, etching steps 18 and 20 etching the nickel-phosphorus alloy film formed on the inner peripheral surface in the plating step, and a lens assembling step assembling the lenses 4a and 4b in the metallic cylinder after the nickel-phosphorus alloy film is etched in the etching step so as to obtain a lens cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel incorporated in various optical devices for changing the optical path of incident light and a method of manufacturing the lens barrel.

[0002]

2. Description of the Related Art In a microscope or an image sensor, it is necessary to enlarge or reduce an optically read image to form an image on a two-dimensional light receiving surface or to form an image at the position of an observer's eye.
One or more lenses are used. When an image is enlarged or reduced by a plurality of lenses, a lens barrel incorporating a plurality of lenses is generally employed.

FIG. 6 is a schematic sectional view of a lens barrel incorporated in a microscope. For example, support rings 3a and 3b are fitted in and fixed to two positions in the axial direction of an inner peripheral surface 2 of a metal cylinder 1 made of a metal material such as aluminum, brass (brass), or copper. The lenses 4a and 4b are supported by the support rings 3a and 3b in a direction orthogonal to the optical axis 10.

[0004] The normal light 5 parallel to the optical axis 10 incident from one surface 6a side of such a lens barrel is applied to each lens 4
In the process of passing through a and b, the light is refracted and passes through the focal point 7. In addition, noise light 8 other than the regular light 5 incident from one surface 6a of the lens barrel enters the inner peripheral surface 2 of the metal cylinder 1 of the lens barrel, and is reflected by the inner peripheral surface 2. hand,
The light passes through the lens 4b and is emitted from the other surface 6b of the lens barrel to the outside of the lens barrel. The noise light 8 or the scattered light generated in the lens barrel acts as noise on the image formed by the regular light 5, so that the resolution of the image formed by the regular light 5 is increased. (S / N ratio) decreases.

In order to suppress a decrease in the resolution (S / N ratio) of a measured image caused by such noise light or scattered light, as shown in FIG. The paint (black paint) 9 is applied. The black paint 9 has a physical property of absorbing incident light in a visible light wavelength range.

Accordingly, noise light 8 incident from one surface 6a of the lens barrel or scattered light generated in the lens barrel is reflected by the black paint 9 coated on the inner peripheral surface 2 of the metal barrel 1. In the process, most of the light power is
And is not emitted from the one surface 6a side of the lens barrel to the outside. As a result, the resolution of the image formed by the regular light 5 is improved.

[0007]

However, as shown in FIG. 6, a lens barrel in which a black paint (black paint) 9 is coated on the inner peripheral surface 2 of a metal barrel 1 still requires the following improvement. There were challenges.

That is, in recent years, an image obtained by a microscope is
In many cases, not only an observer visually confirms, but also a detailed image analysis using a computer is performed. As described above, in order to perform detailed image analysis using a computer, it is necessary to read an image at a higher S / N ratio.

However, since the reflectance of the black paint (black paint) 9 applied to the inner peripheral surface 2 of the metal cylinder 1 is as large as 2-3% in the visible wavelength range, it is formed by the regular light 5 ( This will include a maximum of 2-3% error with respect to the formed image. This maximum error of 2 to 3% causes a reduction in image processing accuracy when the image is processed as it is.

[0010] The present invention has been made in view of such circumstances, and by forming a nickel-phosphorus alloy on the inner peripheral surface of a metal cylinder in which a lens is incorporated, the reflectivity of the inner peripheral surface of the metal cylinder is greatly increased. The lens barrel and the lens mirror, which can greatly reduce the light power of miscellaneous light and scattered light emitted from the metal barrel, and thus can greatly improve the resolution of an image using a lens such as a microscope. An object of the present invention is to provide a method for manufacturing a tube.

[0011]

In order to solve the above-mentioned problems, in a method of manufacturing a lens barrel according to the present invention, a metal tube manufacturing process for manufacturing a metal tube for incorporating a lens, and a metal tube manufacturing process are described. A nickel-phosphorus alloy film formed on the inner peripheral surface by plating a nickel-phosphorous alloy on the inner peripheral surface of the metal cylinder manufactured by the method, and a nickel-phosphorous alloy formed on the inner peripheral surface in this plating process An etching step of etching the film and a lens assembling step of incorporating a lens into a metal cylinder after the nickel-phosphorus alloy film is etched in the etching step to form a lens barrel.

In such a method of manufacturing a lens barrel, a nickel-phosphorus alloy film having a large infrared and visible light absorbing property over a wide wavelength range from an infrared wavelength range to a visible light wavelength range is used. It is formed on the inner peripheral surface of the metal cylinder by plating.

Further, the nickel-phosphorus alloy film formed on the inner peripheral surface of the metal cylinder is etched to form irregularities on the surface of the nickel-phosphorus alloy film. Embodied. If the pitch and the depth of the unevenness are substantially the same order with respect to the wavelength of light, the absorptivity for light is further improved by forming the unevenness on the surface.

Therefore, noise light which enters the metal cylinder from the outside and abuts on the inner peripheral surface and scattered light generated in the metal cylinder and abuts on the inner peripheral surface are formed on the inner peripheral surface. The surface is absorbed by the etched nickel-phosphorus alloy (black body) film and is not emitted out of the metal cylinder. Therefore,
The resolution (S / N) of an image created using this lens barrel
Ratio) is improved.

According to another aspect of the present invention, there is provided a method of manufacturing a lens barrel for manufacturing a metal barrel for incorporating a lens, and a method of manufacturing a metal barrel including an inner peripheral surface of the metal barrel manufactured in the metal barrel manufacturing step. A deposition step of depositing a nickel-phosphorus alloy to form a nickel-phosphorus alloy film on the inner peripheral surface, an etching step of etching the nickel-phosphorus alloy film formed on the inner peripheral surface in the deposition step, and an etching step A lens assembling step of incorporating a lens into the metal cylinder after the nickel-phosphorus alloy film is etched in step (a) to form a lens barrel.

In such a method for manufacturing a lens barrel, the nickel-phosphorus alloy film for absorbing light is formed on the inner peripheral surface of the metal cylinder by a vapor deposition technique, not by a plating technique. Then, irregularities are formed on the surface of the nickel-phosphorus alloy film formed by this vapor deposition technique by an etching technique. Therefore, it is possible to achieve substantially the same operation and effect as the above invention.

Further, in a method of manufacturing a lens barrel according to another invention, a metal barrel manufacturing step of manufacturing a metal barrel for incorporating a lens, and etching one side of a nickel-phosphorus alloy sheet formed in a sheet shape are performed. Etching process and the nickel etched in this etching process
With the phosphor alloy sheet facing the inner surface,
A step of attaching a sheet to the inner peripheral surface of the metal cylinder, and a step of incorporating a lens into the metal cylinder after the nickel-phosphorus alloy sheet is adhered to the inner peripheral surface in the sheet attaching step to form a lens barrel. And

In such a method for manufacturing a lens barrel, one surface of a nickel-phosphorus alloy sheet is etched to form irregularities, and then this nickel-phosphorus alloy sheet is attached to the inner peripheral surface of the metal tube. Like that. In such a manufacturing method, a step of attaching the nickel-phosphorus alloy sheet to the inner peripheral surface of the metal cylinder is required, but the etching step is simplified.

Still another aspect of the invention is a lens barrel in which a lens is incorporated in a metal cylinder, wherein a nickel-phosphorus alloy film whose surface is etched is formed on the inner peripheral surface of the metal cylinder.

In the lens barrel configured as described above, since the nickel-phosphorus alloy film whose surface is etched is formed on the inner peripheral surface of the metal cylinder, it is incident from the outside as described above. The noise light and the scattered light generated in the metal cylinder are absorbed by the nickel-phosphorus alloy (black body) film whose surface formed on the inner peripheral surface is etched, and are not emitted out of the metal cylinder.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a schematic sectional view showing a schematic configuration of a lens barrel according to a first embodiment of the present invention. FIG.
The same reference numerals are given to the same portions as those of the conventional lens barrel shown in FIG.

For example, aluminum or brass
The metal cylinder 1 formed of a metal material such as copper or copper has, for example, an axial length L of 50 to 200 mm and an outer diameter D of 20 to 100.
mm and a thickness T = 5 to 10 mm. And
Support rings 3a, 3b are fitted and fixed in the axial direction at two axial positions of the inner peripheral surface 2 of the metal cylinder 1. The lenses 4a and 4b are supported by the support rings 3a and 3b in a direction orthogonal to the optical axis 10.

On the inner peripheral surface 2 of the metal tube 1 of the lens barrel, nickel-phosphorus (Ni-P) whose surface has been etched
An alloy film 11 is formed. This nickel-phosphorus alloy film 11 is generally made of a super black coating (UB-NIP; Ul).
tra-Black Nickel-Phosphorus Alloy), which has large infrared and visible light absorption characteristics over a wide wavelength range from the infrared wavelength region to the visible light wavelength region. The nickel-phosphorus alloy film 1 of this embodiment
No. 1 has higher light absorption characteristics in the visible light wavelength region.

FIG. 3 shows an inner peripheral surface 2 of a metal barrel 1 of a lens barrel.
FIG. 3 is a cross-sectional view of the nickel-phosphorus alloy film 11 formed in FIG. The thickness t of the nickel-phosphorus alloy film 11 is 10 to 2
0 μm. On the surface of the nickel-phosphorus alloy film 11, irregularities 12 having a pitch p of 0.2 to 0.5 μm and a depth d of 0.4 to 2 μm are formed. The irregularities 12 are formed by etching the surface of the nickel-phosphorus alloy film 11. Unevenness 1
The pitch p of 2 and the depth d of the concave portion can be set to arbitrary values within a certain allowable range by adjusting processing conditions such as the processing time of the etching process.

When the light 13 is incident on the nickel-phosphorus alloy film 11 having the unevenness 12 formed on the surface, the light 13 is incident on the concave portion of the unevenness 12 as shown in FIG. Then, the light collides with the side wall in the concave portion and is reflected. The reflected light 13 collides with the opposite side wall in the same recess and is reflected. As described above, the light 13 that has entered the concave portion of the unevenness 12 consumes the energy of the light 13 while being repeatedly reflected in the concave portion. As a result, the incident light 13 is generated by the nickel-phosphorus alloy film. 11 will be absorbed.

The pitch p and depth d of the irregularities 12 are
If the wavelength is of the same order or more, it is possible to maximize the effect of absorbing the light 13 described above. In this embodiment, the pitch p (=
0.2 to 0.5 μm) and a depth d (= 0.4 to 2 μm). Specifically, numerical values are obtained by experiments.

In order to efficiently absorb not only visible light but also infrared light having a long wavelength, the depth d of the concave portion of the unevenness 12 may be set to about 10 times the depth d for visible light. In this case, the nickel-phosphorus alloy film 1
The thickness t of 1 is desirably 30 to 60 μm.

Conversely, if the light to be absorbed is limited to visible light, the depth d of the concave portion of the concave and convex portion 12 is reduced to 1/10 as compared with the case where the light covers a wide wavelength range including infrared rays. Can be set.

As described above, in the nickel-phosphorus alloy film 11 having the irregularities 12 formed on the surface by the etching process, the reflectance of the incident visible light can be reduced to 2-3 in the case where the conventional black paint is used. % To 0.2%
It was able to be reduced to 0.3% or about 1/10.

In the thus constructed lens barrel, normal light 5 parallel to the optical axis 10 incident from one surface 6a of the lens barrel is refracted while passing through the lenses 4a and 4b. Then, the light passes through the focal point 7 and forms an image at the focal position or the position of the observer's eye.

The noise light 8 other than the regular light 5 or the scattered light generated in the lens barrel, which is incident from one surface 6a of the lens barrel, is incident on the inner peripheral surface 2. Most of the energy is absorbed by the nickel-phosphorus alloy film 11 formed on the inner peripheral surface 2. Therefore, the noise light 8 or the scattered light passes through the lens 4b,
The light is not emitted from the other surface 6b of the lens barrel to the outside of the lens barrel. Therefore, the resolution (S / N ratio) of the image formed by the regular light 5 can be greatly improved.

(Second Embodiment) FIG. 2 is a process chart showing a method for manufacturing a lens barrel according to a second embodiment of the present invention. The same parts as those of the lens barrel according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals.

A bar-shaped aluminum material 14 having dimensions one size larger than that of the metal cylinder 1 shown in FIG. 1 is mounted on a machine tool 15 such as a lathe and machined into a metal cylinder 1 having the dimensions and shape shown in FIG. To produce a metal cylinder 1.

Next, the produced metal cylinder 1 is placed in a plating solution 17.
Is immersed in the plating tank 16 in which is stored. In this case, the metal cylinder 1
The side surface and the outer peripheral surface other than the inner peripheral surface 2 where no plating is performed are masked. The plating solution 17 is made of nickel sulfate, sodium hypophosphite, or the like. And 4.5-
Plating is performed under electroless plating conditions of 5.5 PH, a temperature of 80 ° to 95 ° C., and 1 to 3 hours. Next, the plating tank 16
The metal tube 1 after the plating process is taken out of the
In step a, the plating solution 17 attached is washed.

In this state, the inner peripheral surface 2 of the metal cylinder 1
Has a nickel-phosphorus alloy film having a thickness d = 10 to 12 μm.

Next, the metal cylinder 1 having the nickel-phosphorus alloy film formed on the inner peripheral surface 2 is immersed in an etching bath 19 containing an etching solution 20. Etching solution 20
Is composed of sulfuric acid, sodium nitrate and the like. Then, the etching process is performed at a temperature of 40 ° C. to 60 ° C. for 1 to 5 minutes. Next, the metal tube 1 after the etching process is taken out of the etching tank 19 and is washed with a cleaning machine 18b.
The adhering etchant 20 is washed.

In this state, the inner peripheral surface 2 of the metal cylinder 1
On the surface of the nickel-phosphorus alloy film 11 having a thickness d = 10 to 20 μm formed as shown in FIG.
The irregularities 12 having a depth of 0.2 to 0.5 μm and a depth d of 0.4 to 2 μm are formed.

As described above, the inner circumferential surface 2 of the metal cylinder 1 having the nickel-phosphorus alloy film 11 formed on the inner circumferential surface 2 has an axial width of 2 mm.
The support rings 3a and 3b are attached to the locations, and the lenses 4a and 4b are assembled into the support rings 3a and 3b to form a lens barrel.

As described above, the nickel-phosphorus alloy film 11 is formed on the inner peripheral surface 2 of the metal cylinder 1 by plating, and the nickel-phosphorus alloy film 1 is formed by etching.
Since the irregularities 12 are formed on the surface of the light-emitting device 1, a light-absorbing film having high light-absorbing characteristics can be easily realized in the visible light wavelength region.

Therefore, it is possible to easily manufacture a lens barrel capable of greatly improving the resolution (S / N ratio) of an image formed by the regular light 5.

(Third Embodiment) FIG. 4 is a process chart showing a method for manufacturing a lens barrel according to a third embodiment of the present invention. The same parts as those in the method for manufacturing the lens barrel according to the second embodiment shown in FIG.

A rod 14 having a dimension one size larger than the metal cylinder 1 shown in FIG. 1 is mounted on a machine tool 15 such as a lathe and machined into a shape having the dimensions and shape shown in FIG. The cylinder 1 is manufactured.

Next, the manufactured metal cylinder 1 and nickel
The phosphorus alloy is disposed facing the inside of the vacuum vessel of the vacuum evaporation apparatus 21. Then, the pressure in the vacuum vessel is reduced to a vacuum state, and the nickel-phosphorus alloy is heated, so that the nickel-phosphorus alloy film 11 is uniformly deposited on the inner peripheral surface 2 of the metal cylinder 1. In this case, the side surface and the outer peripheral surface other than the inner peripheral surface 2 where the metal cylinder 1 is not deposited are masked.

As a result, on the inner peripheral surface 2 of the metal tube 1 taken out from the vacuum evaporation apparatus 21, the thickness d = 10 to 20 μm
Is formed. The thickness d of the nickel-phosphorus alloy film can be set to an arbitrary value by adjusting the amount of the nickel-phosphorus alloy set in the vacuum vessel.

Next, the metal cylinder 1 having the nickel-phosphorus alloy film formed on the inner peripheral surface 2 is immersed in an etching tank 19 containing an etching solution 20. The processing contents of this etching step and each of the cleaning step and the lens assembling step after this etching step are almost the same as those in the manufacturing step shown in FIG.

In the method for manufacturing a lens barrel according to the third embodiment, the step of forming a nickel-phosphorus alloy film on the inner peripheral surface 2 is referred to as a “plating step” in the second embodiment.
Since only the “vacuum deposition process” was changed from FIG.
It is possible to obtain substantially the same effect as the method of manufacturing the lens barrel according to the second embodiment shown in FIG.

(Fourth Embodiment) FIG. 5 is a process chart showing a method for manufacturing a lens barrel according to a fourth embodiment of the present invention. The same parts as those in the method for manufacturing the lens barrel according to the second embodiment shown in FIG.

A bar-shaped aluminum material 14 having a size one size larger than the metal cylinder 1 shown in FIG. 1 is mounted on a machine tool 15 such as a lathe and processed into a shape having the size and shape shown in FIG. The cylinder 1 is manufactured.

On the other hand, a film-shaped nickel-phosphorus alloy sheet 22 having a thickness t = 10-20 μm is manufactured. The shape of the nickel-phosphorus alloy sheet 22 is large enough to cover the inner peripheral surface 2 of the metal cylinder 1.

The manufactured nickel-phosphorus alloy sheet 22 is immersed in an etching bath 19 containing an etching solution 20 with one surface thereof being masked. Then, an etching process is performed on one surface of the nickel-phosphorus alloy sheet 22 under the same conditions as the etching process conditions in the manufacturing method of the second embodiment shown in FIG. Next, the nickel-phosphorus alloy sheet 22 after the etching treatment is taken out of the etching tank 19, and the attached etching solution 20 is washed by the washing machine 18b.

In this state, the pitch p = p on the surface of the nickel-phosphorus alloy sheet 22 as shown in FIG.
A large number of irregularities 12 having a thickness of 0.2 to 0.5 μm and a depth d of 0.4 to 2 μm are formed.

Next, the nickel-phosphorus alloy sheet 22
Is adhered to the inner peripheral surface 2 of the previously produced metal tube 1 using an adhesive with the etched surface facing the inner surface. Therefore,
In this state, a nickel-phosphorus alloy film 11 having the cross-sectional shape shown in FIG.

The nickel-phosphorus alloy film 11 is formed on the inner peripheral surface 2.
The support rings 3a and 3b are attached to two positions in the axial direction of the inner peripheral surface 2 of the metal cylinder 1 in which the support ring 3 is formed.
The lenses 4a and 4b are assembled into the lens barrels a and 3b to form a lens barrel.

In the method of manufacturing the lens barrel according to the fourth embodiment, a film-shaped nickel-phosphorus alloy sheet 22 is formed, and one side (front surface) of the nickel-phosphorus alloy sheet 22 is formed. ) Is etched to form the irregularities 12, and then this nickel-phosphorus alloy sheet 22 is attached to the inner peripheral surface 2 of the metal cylinder 1.

In such a manufacturing method, 10 to 2
A step of attaching a very thin film-like nickel-phosphorus alloy sheet 22 having a thickness of 0 μm to the inner peripheral surface 2 of the metal cylinder 1 is required. However, since the sheet is only etched, the etching step is simplified.

[0056]

As described above, in the lens barrel and the method of manufacturing the same according to the present invention, the nickel-phosphorus alloy film is formed on the inner peripheral surface of the metal cylinder in which the lens is to be incorporated. Etching the surface of the film,
Irregularities are formed.

Therefore, the reflectivity of the inner peripheral surface of the metal cylinder can be greatly reduced, and the light power of miscellaneous light and scattered light emitted from the metal cylinder can be greatly suppressed. The resolution of the image can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a lens barrel according to a first embodiment of the present invention.

FIG. 2 is a process chart showing a method for manufacturing a lens barrel according to a second embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a nickel-phosphorus alloy film formed on an inner peripheral surface of a lens barrel.

FIG. 4 is a process chart showing a method for manufacturing a lens barrel according to a third embodiment of the present invention.

FIG. 5 is a process chart showing a method for manufacturing a lens barrel according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a schematic configuration of a conventional lens barrel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal cylinder 2 ... Inner peripheral surface 3a, 3b ... Support ring 4a, 4b ... Lens 5 ... Light 10 ... Optical axis 11 ... Nickel-phosphorus alloy film 12 ... Unevenness 14 ... Aluminum agent 15 ... Machine tool 16 ... Plating tank 19 ... Etching tank 21 ... Vacuum deposition equipment 22 ... Nickel-phosphorus alloy sheet

Claims (4)

[Claims] 1. A metal tube manufacturing step (15) for manufacturing a metal tube (1) for incorporating lenses (4a, 4b), and an inner peripheral surface (2) of the metal tube manufactured by the metal tube manufacturing process.
Plating step of plating a nickel-phosphorus alloy on the inner peripheral surface by plating a nickel-phosphorus alloy on the inner peripheral surface (16.
17) and an etching step (19, 2) for etching the nickel-phosphorus alloy film formed on the inner peripheral surface in the plating step.
0), and a lens assembling step of assembling a lens into a lens barrel after the nickel-phosphorus alloy film has been etched in this etching step. 2. A metal tube manufacturing step (15) for manufacturing a metal tube (1) for incorporating lenses (4a, 4b), and an inner peripheral surface (2) of the metal tube manufactured by the metal tube manufacturing process.
(21) forming a nickel-phosphorus alloy film (11) on the inner peripheral surface by vapor-depositing a nickel-phosphorus alloy on the inner peripheral surface; Etching process for etching (19, 20)
And a lens incorporation step of incorporating a lens into the metal cylinder after the nickel-phosphorus alloy film is etched in the etching step to form a lens barrel. 3. A metal tube manufacturing step (15) for manufacturing a metal tube (1) for incorporating lenses (4a, 4b), and a nickel-phosphorus alloy sheet (2) formed in a sheet shape.
2) etching step for etching one side (19,
20) a sheet attaching step of attaching the nickel-phosphorus alloy sheet etched in this etching step to the inner peripheral surface (2) of the metal cylinder with the etched surface facing the inner surface; A lens assembling step of assembling a lens into a metal cylinder after a nickel-phosphorus alloy sheet is attached to an inner peripheral surface thereof to form a lens barrel. 4. A lens (4a, 4b) in a metal cylinder (1).
Wherein a nickel-phosphorus alloy film (11) whose surface is etched is formed on an inner peripheral surface (2) of the metal tube.