JP2003075698A - Method for assembling optical unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for assembling an optical unit by which the deterioration of planar accuracy of an optical functional plane and dew formation are hardly caused. SOLUTION: By a method for assembling an optical unit which is composed of a combination of a plurality of optical elements having a flange part in a way that the optical functional planes of the optical elements form a gap, the assembly is performed in an environment which is filled with an inert gas. Further, the assembly is performed in a clean environment of the class 100,000 or smaller. Further, the assembly is performed under a reduced pressure by evacuation. Further, the assembly is performed in an environment in which the humidity is 60%RH or smaller. Further, the assembly is performed under the condition of a combination of at least two of the environment filled with the inert gas, the clean environment of the class 100,000 or smaller, the environment under a reduced pressure by evacuation and the environment in which the humidity is 60%RH or smaller. Further, the parts which form a gap between the optical elements after assembled are not grounded before combining a plurality of optical elements.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of assembling an optical unit, and more particularly to a method of assembling an optical unit in which a first optical element and a second optical element are integrated.

[0002]

2. Description of the Related Art Conventionally, a first optical element having an optical functional surface and a second optical element having an optical functional surface are provided.
There is an optical unit in which the first optical element and the second optical element are integrated.

[0003]

As described above, when two or more optical elements are combined to form one optical unit, it is necessary to accurately combine them.

For example, in the case of an objective lens for an optical pickup, the performance may not be achieved due to the occurrence of tilt rather than the shift of the optical axis. Particularly in recent years, due to high density, high precision is required for the objective lens, and therefore tilt is small and optical axis shift is small, and it is necessary to combine a single lens (or an optical element).

In such an optical unit, the first
The gap surrounded by the optical element and the second optical element is in a hermetically sealed state. However, when this gap is in a hermetically sealed state, when the operating environment temperature and humidity of this optical unit changes, it is included in this gap. The water content may become saturated and may condense on the optical function surface on the gap side, affecting the optical performance.

In recent years, there is an increasing demand for optical elements for optical discs that are highly accurate and inexpensive. For example, when the objective lens for an optical disc has a gap, the above-mentioned dew condensation cannot be ignored and has become a problem. That is, due to a change in ambient temperature, water vapor is condensed in the gap between the optical elements,
This is a problem of adhesion to the surface of the optical function surface, and if this dew condensation occurs, the optical function cannot be achieved.

The present invention has been made in view of the above problems, and an object thereof is to provide an assembling method of an optical unit in which dew condensation is unlikely to occur.

[0008]

In order to solve the above-mentioned problems and to achieve the object, the present invention has the following constitution.

According to a first aspect of the invention, in the method of assembling an optical unit in which a plurality of optical elements having a flange portion are combined so that optical function surfaces of the optical elements have a gap, A method of assembling an optical unit, which comprises assembling in an atmosphere filled with gas. ].

According to the invention described in claim 1, by assembling in an atmosphere filled with an inert gas, the gap between the optical functional surfaces of the optical elements is filled with the inert gas,
Even if the operating environment temperature and humidity change, water vapor is prevented or suppressed from being condensed in the gap between the optical functional surfaces and attached to the surface of the optical functional surface on the gap side.

According to a second aspect of the present invention, there is provided a method of assembling an optical unit in which a plurality of optical elements having a flange portion are combined so that optical function surfaces of the optical elements have a gap, and a class 100 is provided. A method for assembling an optical unit, characterized in that the assembling is performed in a dust removing atmosphere of 1,000 or less. ].

According to the second aspect of the invention, by assembling in a dust-removing atmosphere of class 100,000 or less, dust is prevented from being filled in the gap between the optical function surfaces of the optical elements. As a result, it is possible to prevent water from aggregating with the dust as a core, and to prevent or suppress dew condensation in the gap between the optical function surfaces and adhesion to the surface of the optical function surface on the gap side.

According to a third aspect of the present invention, there is provided a method of assembling an optical unit, wherein a plurality of optical elements having a flange portion are combined so that optical function surfaces of the optical elements have a gap, and vacuum decompression is performed. A method for assembling an optical unit, characterized by performing the assembly below. ].

According to the third aspect of the present invention, by assembling under a vacuum reduced pressure, the gap between the optical function surfaces of the optical elements becomes a vacuum state, and when the use environment temperature and humidity change, Since the gap is in a vacuum state, it does not expand or compress and no external pressure is applied to the first optical element and the second optical element. Therefore, the surface accuracy of the optical functional surface can be maintained, and the optical functional surface between the optical elements can be maintained. Water vapor is condensed in the gap between the
Adhesion to the surface of the optical function surface on the gap side is prevented or suppressed.

According to a fourth aspect of the present invention, there is provided a method of assembling an optical unit, wherein a plurality of optical elements having flange portions are combined so that optical function surfaces of the optical elements have a gap, A method of assembling an optical unit, characterized by performing the assembly under an atmosphere of 60% RH or less. ].

According to the invention described in claim 4, by assembling in an atmosphere having a humidity of 60% RH or less, the gap between the optical functional surfaces of the optical elements becomes a low humidity state, and the operating environment When the temperature and humidity change, water vapor is prevented or suppressed from being condensed in the gap between the optical functional surfaces of the optical elements and attached to the surface of the optical functional surface on the gap side.

According to a fifth aspect of the invention, in the method of assembling an optical unit in which a plurality of optical elements having a flange portion are combined so that the optical functional surfaces of the optical elements have a gap, In an atmosphere filled with gas,
A method for assembling an optical unit, characterized in that assembly is performed under conditions of at least two or more combinations in a dust-removing atmosphere of class 100,000 or less, under vacuum reduced pressure, and in an atmosphere having a humidity of 60% RH or less. ].

According to the invention described in claim 5, at least 2 in an atmosphere filled with an inert gas, a dust-removing atmosphere of class 100,000 or less, a vacuum reduced pressure, and an atmosphere of 60% RH or less in humidity. By assembling under the conditions of the above combination, the surface accuracy of the optical functional surface can be maintained more, and water vapor is condensed in the gap between the optical functional surfaces of the optical elements and adheres to the surface of the optical functional surface on the gap side. Can be prevented or suppressed.

According to a sixth aspect of the present invention, there is provided a method of assembling an optical unit, wherein a plurality of optical elements having a flange portion are combined so that optical function surfaces of the optical elements have a gap. The method for assembling an optical unit, characterized in that the portion forming the gap is not grounded before the optical elements of (1) are combined. ].

According to the sixth aspect of the present invention, before combining the plurality of optical elements, the portion forming the gap is not grounded, so that the gap between the optical function surfaces of the optical elements is filled with dust. Can be prevented, dust does not adhere to the surface of the optical function surface on the gap side, and moisture is less likely to agglomerate with the dust as the nucleus, and dew condensation occurs in the gap between the optical function surfaces. Adhesion to the surface of the side optical function surface is prevented or suppressed.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A method of assembling an optical unit according to an embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 to 5 are views showing a method of assembling an optical unit. In the embodiment of FIG. 1, the optical unit 2 is composed of a first optical element 4 and a second optical element 5. The first optical element 4 has two optical function surfaces 4a1 and 4a2, a flange portion 4b protruding in a direction perpendicular to the optical axis Z, a contact surface 4f with the second optical element 5, and a fitting with the second optical element. Each has a portion 4g. The first optical element 4 is a plastic-molded positive lens.

The second optical element 5 has two optical function surfaces 5a.
1, 5a2, a flange portion 5b protruding in the direction perpendicular to the optical axis Z, a contact surface 5f with the first optical element 4, and a fitting portion 5g with the first optical element 4. In addition, the second optical element 5
Is a plastic molded positive lens.

In the first optical element 4 and the second optical element 5, the flange portions 4b and 5b are fitted over substantially the entire circumference, and the fitting portions 4g and 5g are in close contact with each other. In the optical unit 2, the gap 21 between the optical function surfaces 4a2 and 5a1 of the optical elements is sealed by the fitting portions 4g and 5g, and the gap 21 exists between the optical function surfaces 4a2 and 5a1 of the optical elements. To combine.

In the embodiment of FIG. 2, the first optical element 4 has the same structure as that of FIG. 1, but the flange portion 4b is
Engagement protrusions 4h protruding inward are formed at a plurality of locations. The second optical element 5 is also configured in the same manner as in FIG. 1, but the flange portion 5b has engagement claws 5 protruding in a plurality of positions in the Z-axis direction.
h is formed. The projection 4h of the first optical element 4 and the second
The engagement claws 5h of the optical element 5 are engaged, and the first optical element 4 and the second optical element 5 are vanette-bonded.

In the embodiment of FIG. 3, the first optical element 4 has the same structure as that of FIG.
Protrusions 4i protruding inward are formed at a plurality of positions of the fitting portion 4g. The second optical element 5 is also configured in the same manner as in FIG. 1, but the flange portion 5b has convex portions 5i protruding inward at a plurality of positions of the fitting portion 5g. The protrusion amount l of the convex portion 4i and the convex portion 5i is several μm, and when the fitting portion 4g of the first optical element 4 and the fitting portion 5g of the second optical element 5 are fitted, the convex portion 4i and the convex portion 4i The joint strength is increased by 5i, and the first optical element 4 and the second optical element 5 are firmly joined.

In the embodiment of FIG. 4, the first optical element 4 and the second optical element 5 are constructed in the same manner as in FIG.
As shown in (a), the fitting portion 4g of the first optical element 4 is coated with the liquid 8 for dissolving the breezed plastic. Then, as shown in FIG. 4B, when the fitting portion 5g of the second optical element 5 is fitted into the fitting portion 4g of the first optical element 4, the liquid 8 that melts the plastic is fitted into the fitting portions 4g and 5g. The melting strength increases the bonding strength, and the first optical element 4 and the second optical element 5 are firmly bonded. After the first optical element 4 and the second optical element 5 are bonded, as shown in FIG. 4C, the liquid 8 that dissolves the plastic volatilizes with the passage of time.

The optical unit as shown in FIGS. 1 to 4 is assembled in an atmosphere filled with an inert gas. By performing the assembly in the atmosphere filled with the inert gas as described above, the optical function surfaces 4a2 and 5a of the optical elements are formed.
Even when the gap 21 between the optical functional surfaces 4a2 and 5a1 is filled with an inert gas and the operating environment temperature and humidity changes, water vapor is condensed in the gap 21 between the optical functional surfaces 4a2 and 5a1.
Adhesion to the surface of 2,5a1 is prevented or suppressed.

Further, the optical unit as shown in FIGS. 1 to 4 is assembled in a dust removing atmosphere of class 100,000 or less. Class 100,000 or less is a case where the number of particles having a particle size of 0.5 μm or more in 1 ft ³ is 100,000 or less.

By thus assembling in a dust-removing atmosphere of class 100,000 or less, it is possible to prevent dust from being filled in the gap 21 between the optical function surfaces 4a2, 5a1 of the optical elements, and this dust is removed. Water is less likely to aggregate as a core, and the gap 2 between the optical function surfaces 4a2 and 5a1 is reduced.
It is possible to prevent or suppress dew condensation caused by No. 1 and adhesion to the surfaces of the optical function surfaces 4a2 and 5a1 on the gap side.

The optical unit as shown in FIGS. 1 to 4 is assembled under reduced pressure in a vacuum. By performing the assembly under reduced pressure in the vacuum in this manner, the optical functional surface 4 between the optical elements is
When the gap 21 between the a2 and 5a1 is in a vacuum state and the ambient temperature and humidity of the environment changes, the gap 21 is in a vacuum state, so that the gap 21 does not expand or compress.
Since no external pressure is applied to the optical element 5, the surface accuracy of the optical function surfaces 4a2 and 5a1 can be maintained, and water vapor is condensed in the gap 21 between the optical function surfaces 4a2 and 5a1 of the optical elements, so that the gap side optical Adhesion to the surfaces of the functional surfaces 4a2 and 5a1 can be prevented or suppressed.

Further, the optical unit as shown in FIGS. 1 to 4 is assembled in an atmosphere having a humidity of 60% RH or less. By thus assembling in an atmosphere having a humidity of 60% RH or less, the optical function surfaces 4a2, 5a of the optical elements are
When the gap 21 between the two becomes a low humidity state and the use environment temperature and humidity change, the optical function surfaces 4a2, 5 of the optical elements are changed.
It is possible to prevent or suppress the dew condensation of water vapor in the gap 21 between the a1 and the adhesion to the surfaces of the optical function surfaces 4a2 and 5a1 on the gap side.

The assembly of the optical unit as shown in FIGS. 1 to 4 is carried out under the atmosphere filled with the inert gas in the class 10 class.
Humidity of 6 or less in a dust-removing atmosphere of 50,000 or less
Assembly is performed under the condition of at least two combinations under an atmosphere of 0% RH or less.

At least 2 under such an atmosphere filled with an inert gas, a dust-removing atmosphere of class 100,000 or less, a vacuum reduced pressure, and an atmosphere of 60% RH or less in humidity.
By assembling under the conditions of the above combination, the surface accuracy of the optical function surfaces 4a2, 5a1 can be further maintained, and water vapor is condensed in the gap 21 between the optical function surfaces 4a2, 5a1 of the optical elements, and It is possible to prevent or suppress the adhesion to the surfaces of the optical function surfaces 4a2 and 5a1.

(Second Embodiment) In this embodiment, as in the embodiment of FIG. 1, the first optical element 4 and the second optical element 4 are used.
The optical element 5 is configured, but as shown in FIG. 5, before the first optical element 4 and the second optical element 5 are combined,
The optical element 4 grounds the flange 4b and the optical functional surface 4a1, and the second optical element 5 connects the flange 5b and the optical functional surface 5a2.
And are grounded, and the parts forming the gap 21 are not grounded. Before combining in this way, by not grounding the part constituting the gap portion 21, it is possible to prevent dust from being filled in the gap between the optical function surfaces of the optical elements, and to prevent the surface of the optical function surface on the gap side from being filled. Dust is not attached, and moisture is less likely to be aggregated by using the dust as a core, so that dew condensation is prevented in the gap between the optical function surfaces and is prevented from attaching to the surface of the optical function surface on the gap side. Suppressed.

[0036]

As described above, according to the first aspect of the present invention, by performing the assembly in the atmosphere filled with the inert gas, the gap between the optical functional surfaces of the optical elements is filled with the inert gas. Therefore, even when the use environment temperature and humidity are changed, water vapor is prevented or suppressed from being condensed in the gap between the optical functional surfaces and attached to the surface of the optical functional surface on the gap side.

In the invention described in claim 2, class 10
By assembling in a dust-removing atmosphere of 10,000 or less, it is possible to prevent dust from being filled in the gap between the optical functional surfaces of the optical elements, and to attach the dust to the surface of the optical functional surface on the gap side. In addition, water is less likely to agglomerate with this dust as a core, and condensation occurs in the gap between the optical function surfaces,
Adhesion to the surface of the optical function surface on the gap side is prevented or suppressed.

According to the third aspect of the present invention, when the assembly is performed under reduced pressure in a vacuum, the gap between the optical functional surfaces of the optical elements is in a vacuum state, and the operating environment temperature and humidity change,
Since the gap is in a vacuum state, it does not expand or compress, and the external pressure is not applied to the optical element, so the surface accuracy of the optical functional surface can be maintained. Adhesion to the surface of the side optical function surface is prevented or suppressed.

In the invention described in claim 4, the humidity is 60%.
By assembling in an atmosphere of RH or less, the gap between the optical functional surfaces of the optical elements becomes a low humidity state, and when the operating environment temperature and humidity changes, water vapor is generated in the gap between the optical functional surfaces of the optical elements. Can be prevented or suppressed from being condensed and attached to the surface of the optical function surface on the gap side.

In the invention according to claim 5, at least two or more combinations of an atmosphere filled with an inert gas, a dust-removing atmosphere of class 100,000 or less, a vacuum reduced pressure, and an atmosphere of a humidity of 60% RH or less are combined. By assembling under these conditions, the surface accuracy of the optical function surface can be maintained more, and water vapor can be condensed in the gap between the optical function surfaces of the optical elements and adhere to the surface of the optical function surface on the gap side. It can be prevented or suppressed.

According to the sixth aspect of the present invention, before combining a plurality of optical elements, by not grounding the part forming the gap, dust is filled in the gap between the optical function surfaces of the optical elements. Can be prevented, dust does not adhere to the surface of the optical function surface on the gap side, and water is less likely to aggregate by using this dust as a nucleus, and dew condensation occurs in the gap between the optical function surfaces, The adhesion to the surface of the optical function surface is prevented or suppressed.

[Brief description of drawings]

FIG. 1 is a diagram showing a method of assembling an optical unit.

FIG. 2 is a diagram showing a method of assembling an optical unit according to another embodiment.

FIG. 3 is a diagram showing a method of assembling the optical unit according to another embodiment.

FIG. 4 is a diagram showing a method of assembling the optical unit according to another embodiment.

FIG. 5 is a diagram showing a method of assembling the optical unit according to another embodiment.

[Explanation of symbols]

2 Optical unit 4 First optical element 5 Second optical element 4a1, 4a2, 5a1, 5a2 Optical functional surface 4b, 5b Flange part 4g, 5g fitting part 21 Gap Z optical axis

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 13/00 G02B 13/00 (72) Inventor Noriichi Arai 2970 Ishikawa-cho, Hachioji, Tokyo Konica Stock Association In-house (72) Inventor Koji Honda, 2970 Ishikawa-cho, Hachioji, Tokyo Konica Stock Company, in-house (72) Inventor, Yuichi Honda, 2970 Ishikawa-cho, Hachioji, Tokyo, Konica Stock Company, in-house (72) Yuichi Shin, 1 Sakura-cho, Hino-shi, Tokyo Konica Stock In-house F-term (reference) 2H043 AE02 AE04 AE05 AE14 AE23 2H044 AA02 AA11 AA14 AA15 AA17 AB02 AB05 AB16 AB21 AB25 AD02 AD03 2H087 KA13 LA01 NA17 PA02 PA17 PB02 UA01

Claims (6)

[Claims] 1. A plurality of optical elements having a flange portion,
In the method for assembling an optical unit in which the optical functional surfaces of the optical elements are combined so as to have a gap, the assembling method is performed in an atmosphere filled with an inert gas. 2. A plurality of optical elements having a flange portion,
In this method of assembling an optical unit in which optical functional surfaces of optical elements are combined so as to have a gap, the optical unit is assembled in a dust-removing atmosphere of class 100,000 or less. 3. A plurality of optical elements having a flange portion,
In the method of assembling an optical unit in which the optical functional surfaces of the optical elements are combined so as to have a gap, the optical unit is assembled under reduced pressure in a vacuum. 4. A plurality of optical elements having a flange portion,
In the method of assembling an optical unit in which optical functional surfaces of the optical elements are combined so as to have a gap, the assembly is performed in an atmosphere having a humidity of 60% RH or less. 5. A plurality of optical elements having a flange portion,
In the method for assembling an optical unit in which optical function surfaces of optical elements are combined with each other, a class 100,000 is provided in an atmosphere filled with an inert gas.
An optical unit assembling method, characterized in that the optical unit is assembled under the following dust-removing atmosphere, vacuum decompression, and an atmosphere having a humidity of 60% RH or less under a combination of at least two. 6. A plurality of optical elements having a flange portion,
In this method of assembling an optical unit in which optical functional surfaces of optical elements are combined so as to have a gap therebetween, before combining the plurality of optical elements, a portion forming the gap is not grounded. Assembly method.