JP2010007136A - Optical element holding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element holding method which prevents sticking between optical elements, so as to facilitate attachment/detachment, and also has no risk of damages in optical surfaces. <P>SOLUTION: The optical element holding method where, in an optical element 31 having optical surfaces 31A and an outer circumferential face 31B, a thin film is formed on the outer circumferential face 31B comprises a process in which, between the mutual optical surfaces 31A of the plurality of optical elements 31 arranged along the direction of the optical axis, dummy members 32 having fine ruggedness are interposed in such a manner that the contact surfaces 32A confronted with the respective optical surfaces 31A are not made into mirror surfaces. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical element holding method when a thin film is formed on a peripheral wall of an optical element.

  Conventionally, as a device for forming a uniform thin film on the peripheral wall of an optical element, a holding device that holds the optical elements in an overlapping manner is rotated in conjunction with a rotation driving mechanism provided in the device, and the held optical elements are An apparatus is known in which a thin film is formed on a peripheral wall while the peripheral wall is rotated while facing the vapor deposition source (see, for example, Patent Document 1).

In the apparatus described in Patent Document 1, a plurality of lenses on which a thin film is formed are overlapped and held between the first and second lens support members. At this time, each optical element is pressed and held by the first and second lens support members in a state where their optical surfaces are in contact with each other.
JP 2006-200015 A

However, when the optical element is held by the above-described method and a thin film is formed by the vacuum method, the gap on the optical surface of the optical elements that are in contact with each other is also in a vacuum state. Therefore, when air is released after film formation, there is a problem that optical contact is generated on the optical surface, and the optical elements are firmly attached to each other, which makes it very difficult to attach and detach.
Further, when the optical element is rotationally driven, there is a problem that the optical surface slips and the optical surface may be damaged.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical element holding method that prevents sticking of optical elements, facilitates attachment / detachment, and does not cause damage to the optical surface. To do.

  The present invention is an optical element holding method for forming a thin film on the outer peripheral surface of an optical element having an optical surface and an outer peripheral surface, wherein a plurality of the optical elements arranged along the optical axis direction are mutually connected. The method further comprises a step of interposing a dummy member having minute irregularities so that a contact surface facing each optical surface does not become a mirror surface between the optical surfaces.

  According to the optical element holding method of the present invention, a minute gap is always ensured between the optical surface of the optical element and the contact surface of the dummy member, and after film formation in a vacuum environment, between the optical surface and the contact surface. Air enters and sticking due to optical contact is prevented.

  The contact surface of the dummy member may be processed into a grain having fine irregularities. In this case, sticking can be suitably prevented without damaging the optical surface by sliding.

  The grain number may be 800 or more and 3000 or less. In this case, the occurrence of damage to the optical surface can be suppressed to a lower level.

  According to the optical element holding method of the present invention, it is possible to provide an optical element holding method that prevents the optical elements from sticking to each other, facilitates attachment / detachment, and does not cause damage to the optical surface.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating a configuration of an example of a thin film forming apparatus to which the optical element holding method of the present embodiment is applied.
A thin film forming apparatus 1 shown in FIG. 1 includes a thin film forming tank 2, a dome part 3 that is disposed inside the thin film forming tank 2 and to which an optical element is attached, an optical element holding part 4 that is attached to the dome part 3, and a dome. And a vapor deposition source 5 installed below the unit 3.

  The thin film forming tank 2 has a known configuration, and when forming a thin film, the inside is evacuated and the film is formed by vapor deposition.

The dome part 3 has a substantially spherical ceiling part 6 and a substantially cylindrical side wall part 7.
A plurality of recesses 6 </ b> A are formed on the inner surface of the ceiling portion 6. In each recess 6 </ b> A, the optical element holding portion 4 has an axis (specifically, a pinching shaft member 13 </ b> B described later) that is substantially parallel to a tangent to the cross section of the ceiling portion 6 that passes through the central axis of the side wall portion 7. Mounted on.

The side wall portion 7 is arranged so that the central axis coincides with the central axis of the thin film forming tank 2. A ring-shaped gear 8 is provided at the lower end 7A of the side wall portion 7 along the circumferential direction, and the gear 8 is engaged with a rotating shaft 10A of a driving mechanism 10 such as a motor via a driving gear 9. Accordingly, the dome portion 3 is configured to be rotatable around the central axis of the side wall portion 7 by the drive mechanism 10.
Instead of forming the side wall portion 7 in a substantially cylindrical shape, the side wall portion 7 may be formed by supporting the ceiling portion 6 with a plurality of columns and providing a cover between the columns.

  FIG. 2 is an enlarged view of the optical element holding unit 4. The optical element holding part 4 includes a support member 11 that is detachably fixed to the recess 6A, a first holding part 12 and a second holding part 13 that are attached to the support member 11 and hold the optical element. And a driven gear 14 for rotating the optical element.

  The support member 11 is a rod-shaped member, and is provided with a protrusion 11A at one end. The optical element holding part 4 engages the protrusion 11A and the inner surface of the recess 6A by its own weight by fitting one end of the support member into the hole provided in the inner surface of the recess 6A of the ceiling part 6, and the recess 6A. It is detachably fixed in a state where it is positioned inside.

  The 1st clamping part 12 and the 2nd clamping part 13 are each provided with fixing | fixed part 12A, 13A attached to the supporting member 11, and clamping shaft member 12B, 13B attached to fixing | fixed part 12A, 13A. Holes are provided in the fixing portions 12A and 13A. The sandwiching shaft members 12B and 13B are inserted into the holes and are rotatably fixed by bearings 15 so as to face each other. The first holding part 12 on the protruding part 11A side is urged toward the second holding part 13 by an urging means 16 such as a spring arranged between the protruding part 11A and the fixing part 12A.

The driven gear 14 is attached coaxially to the sandwiching shaft member 13B at the end of the sandwiching shaft member 13B opposite to the first sandwiching portion 12. The driven gear 14 meshes with a ring-shaped fixed gear 17 provided above the ceiling portion 6, and rotates with the rotation of the side wall portion 7 to rotate the sandwiching shaft member 13 </ b> B.
The fixed gear 17 is suspended by a plurality of support pillars 18, and the support pillars 18 are attached to the upper part of the inner surface of the thin film forming tank 2 in a state of being connected by a connecting member 19.

The vapor deposition source 5 is disposed at a position on the axis of the side wall portion 7 so as to face the concave portion 6 </ b> A of the ceiling portion 6. And the shape of the ceiling part 6 is set so that the distance to the vapor deposition source 5 is equal at any position on the curved surface of the ceiling part 6. The material of the vapor deposition source 5 is appropriately selected depending on the thin film to be formed.
A known electron gun 20 is disposed in the vicinity of the evaporation source 5, and an electron beam emitted from the electron gun 20 heats and evaporates the film forming material of the evaporation source 5.

  A shutter 21 is provided between the vapor deposition source 5 and the recess 6A. The shutter 21 is fixed to a rotating shaft 21A, and is configured to be retractable from between the vapor deposition source 5 and the recess 6A by rotating the rotating shaft 21A.

A procedure for performing the optical element holding method of the present invention when performing film formation using the thin film forming apparatus 1 configured as described above will be described.
First, as shown in FIG. 3, a plurality of optical elements 31 and a plurality of dummy members 32 having substantially the same diameter as the optical elements 31 are prepared.

  The optical element 31 of the present embodiment is a disk-shaped element made of a glass material, for example, sapphire having a diameter of 4 millimeters (mm) and a thickness of 1.5 mm. Both the optical surface 31A in the axial direction and the outer peripheral surface 31B are polished. The entire surface is in a mirror state. This is merely an example, and the optical element used in the present invention is not limited in material and shape.

  The dummy member 32 is a disk-shaped member made of a white plate, and the diameter and thickness are set to be the same as those of the optical element. Then, as will be described later, the contact surfaces 32A at both ends in the axial direction that come into contact with the optical surface 31A of the optical element 31 are processed into a number 2000 (# 2000) grain having fine irregularities on the surface.

  The processing of the contact surface 32A is preferably # 800 or more and # 3000 or less. If the contact surface 32A is rougher than # 800, the optical surface 31A may be scratched. If the contact surface 32A is smaller than # 3000, the optical surface 31 conforms to the optical contact, and the dummy member 32 may stick to the optical element 31.

  The optical element 31 and the dummy member 32 are arranged alternately and coaxially in the axial direction (optical axis in the optical element 31) and are brought into close contact with each other. Thereby, the dummy member 32 is interposed between the adjacent optical elements 31, and the optical surface 31A of the optical element 31 and the contact surface 32A of the dummy member 32 come into contact (dummy member interposing step). At this time, since both ends of the optical element 31 and the dummy member 32 arranged in contact with the sandwiching shaft members 12B and 13B of the first sandwiching portion 12 and the second sandwiching portion 13 are preferably used as the dummy member 32.

  Next, as shown in FIG. 2, the optical element 31 and the dummy member 32 are sandwiched between the sandwiching shaft members 12 </ b> B and 13 </ b> B of the first sandwiching section 12 and the second sandwiching section 13. At this time, the sandwiched optical element 31 and the dummy member 32 are installed so as to be coaxial with the sandwiching shaft members 12B and 13B. The first clamping unit 12 is urged toward the second clamping unit 13 by the urging means 16, and the optical element 31 and the dummy member 32 are clamped between the first clamping unit 12 and the second clamping unit 13. . The urging force of the urging means 16 is set to a strength that can hold the clamped optical element 31 and the dummy member 32 and the clamping shaft members 12B and 13B so as not to rotate relative to each other.

  The optical element holding part 4 between which the optical element 31 and the dummy member 32 are sandwiched is fixed in the recess 6A by fixing the support member 11 to the recess 6A of the ceiling part 6. At this time, the optical element holding part 4 is arranged so that the rotation axes of the optical element 31 and the dummy member 32, that is, the sandwiching shaft members 12 </ b> B and 13 </ b> B coincide with the tangent line of the curved surface of the ceiling part 6. The surface 31B faces the lower deposition source 5.

  When the drive mechanism 10 is driven to rotate the drive gear 9, the gear 8 rotates and the dome portion 3 rotates around the central axis of the side wall portion 7. The optical element holding part 4 attached to the ceiling part 6 of the dome part 3 rotates together with the dome part 3. At this time, the driven gear 14 meshes with the fixed gear 17 and rotates, and the clamping shaft member 13B of the second clamping unit 13 to which the driven gear 14 is attached rotates. Accordingly, the optical element 31, the dummy member 32, and the clamping shaft member 12 </ b> B of the first clamping unit 12 that are supported coaxially rotate around the axis. That is, the optical element 31 and the dummy member 32 revolve with respect to the vapor deposition source 5 while rotating around the axis.

  Next, when an electron beam is emitted from the electron gun 20 toward the vapor deposition source 5, the film forming material of the vapor deposition source 5 is heated and evaporated. When the rotating shaft 21A of the shutter 21 is rotated to retract the shutter from between the vapor deposition source 5 and the recess 6A, the evaporated film forming material advances straight toward the ceiling 6 and the outer periphery of the optical element 31 and the dummy member 32 Reach the plane. In this way, a thin film having a uniform thickness is formed on the outer peripheral surface 31B of the optical element 31.

According to the above procedure, a thin film having a thickness of 100 nanometers (nm) is formed using gold as the vapor deposition source 5 under the conditions that the temperature in the thin film formation tank 2 is 300 ° C. and the ultimate vacuum is 2 × 10 ⁻⁴ Pa. As a result, sticking due to optical contact did not occur between the optical element 31 and the dummy member 32. And when removing the optical element 31 and the dummy member 32 from an optical element holding | maintenance part, it was able to attach or detach easily, without damaging the optical surface 31A of the optical element 31. FIG.

  According to the optical element holding method of the present invention, the contact member 32A is not a mirror surface, but a dummy member 32 having minute irregularities is interposed between adjacent optical surfaces 31A of a plurality of optical elements 31 arranged in the optical axis direction. Therefore, a minute gap is always ensured between the contact surface 32A and the optical surface 31A. Therefore, even when film formation is performed in a vacuum environment, after the film formation, air enters between the contact surface 32A and the optical surface 31A to prevent sticking due to optical contact and can be easily attached and detached. .

  Moreover, since the contact surface is processed into a # 2000 grain, it is possible to suitably prevent sticking without damaging the optical surface 31A due to slippage.

Next, an optical element holding method according to a second embodiment of the present invention will be described with reference to FIGS. The difference between the optical element holding method of the present embodiment and the optical element holding method of the first embodiment is the shapes of the optical element and the dummy member.
In addition, about each structure already mentioned in the said 1st Embodiment, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  FIG. 4 is a diagram showing the optical element 41 and the dummy member 42 used in the present embodiment. The optical element 41 is an element having a diameter of 10 mm and a thickness of 1.0 mm made of a glass material (trade name S-LAH58: manufactured by OHARA INC.), And the optical surface 41A is a concave spherical surface (R10 concave, R20 concave). ing.

  The dummy member 42 is formed of a white plate like the dummy member 32, and the contact surface 42A is processed into a convex spherical surface (R10 convex, R20 convex) corresponding to the optical surface 41A by a spherical surface generator. The diameter and thickness of the dummy member 42 are the same as those of the optical element 41, and the surface of the contact surface 42A has a grain shape of about # 2000.

  The optical element 41 and the dummy member 42 described above are arranged in the optical axis direction, and are sandwiched and held by the optical element holding unit 4 in the same procedure as in the first embodiment as shown in FIG. At this time, as shown in FIG. 5, as a dummy member that contacts the sandwiching shaft members 12 </ b> B and 13 </ b> B, a member whose one surface is processed into a flat surface may be used. In this way, the optical element 41 and the dummy member 42 can be held in a more stable state.

In the above procedure, magnesium fluoride (MgF ₂ ) was used as the vapor deposition source 5 under the conditions of a temperature in the thin film formation tank 2 of 270 ° C. and an ultimate vacuum of 2 × 10 ⁻⁴ Pa, and a thickness of 130 nm (nm) As a result, no sticking due to optical contact occurred between the optical element 41 and the dummy member 42. And when removing the optical element 41 and the dummy member 42 from the optical element holding part, the optical surface 41A of the optical element 41 could be easily attached and detached without damaging it.

Also in the optical element holding method of the present embodiment, the same effect as the optical element holding method of the first embodiment described above can be obtained.
Since the contact surface 42A of the dummy member 42 is processed into a spherical surface corresponding to the shape of the optical surface 41A of the optical element 41, even an optical element having a spherical optical surface can be suitably held. Can do.

  In the present embodiment, the example in which the optical surface of the optical element is concave and the contact surface of the dummy member is convex has been described, but the contact surface of the dummy member is also supported when the optical surface of the optical element is convex. By forming a concave shape, suitable holding can be performed similarly.

Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, an example in which the dummy member is formed of a white plate has been described. However, instead of this, the dummy member may be formed using another glass material, metal, or the like. However, from the viewpoint of making it difficult to damage the optical surface of the optical element, the dummy member is preferably formed using a material having a hardness lower than the hardness of the optical element.

It is a figure which shows the structure of an example of the thin film formation apparatus with which the optical element holding | maintenance method of 1st Embodiment of this invention is applied. It is a figure which shows the structure of the optical element holding | maintenance part of the thin film forming apparatus. It is a figure which shows the optical element and dummy member clamped by the optical element holding | maintenance part. It is a side view which shows the optical element and dummy member which are used in the optical element holding | maintenance method of 2nd Embodiment of this invention. It is a figure which shows the state by which the optical element and the dummy member were clamped by the optical element holding | maintenance part.

Explanation of symbols

31, 41 Optical elements 31A, 41A Optical surface 31B Outer peripheral surfaces 32, 42 Dummy members 32A, 42A Contact surface

Claims (3)

An optical element holding method for forming a thin film on the outer peripheral surface of an optical element having an optical surface and an outer peripheral surface,
A step of interposing a dummy member having minute irregularities between the optical surfaces of the plurality of optical elements arranged along the optical axis direction so that a contact surface facing each optical surface does not become a mirror surface An optical element holding method comprising:   The optical element holding method according to claim 1, wherein the contact surface of the dummy member is processed into a grain having fine irregularities.   The optical element holding method according to claim 2, wherein the grain size is from 800 to 3000.

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