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EP-4741356-A1 - OPTICAL ELEMENT UNIT, MANUFACTURING METHOD FOR OPTICAL ELEMENT UNIT, AND OPTICAL APPARATUS

EP4741356A1EP 4741356 A1EP4741356 A1EP 4741356A1EP-4741356-A1

Abstract

Provided is an optical element unit including a first optical element and a second optical element, wherein the first optical element and the second optical element are bonded to each other through intermediation of a bonding portion formed by solid-phase bonding of an inorganic substance between a peripheral edge portion of the first optical element and a peripheral edge portion of the second optical element, and wherein the optical element unit has, between the first optical element and the second optical element which are bonded to each other, a hollow portion formed on an inner side of the peripheral edge portion.

Inventors

  • HOSHINO, KAZUHIRO
  • FUKUSHIMA, HIROTAKA

Assignees

  • Canon Kabushiki Kaisha

Dates

Publication Date
20260513
Application Date
20251107

Claims (20)

  1. An optical element unit comprising a first optical element and a second optical element, wherein the first optical element and the second optical element are bonded to each other through intermediation of a bonding portion formed by solid-phase bonding of an inorganic substance between a peripheral edge portion of the first optical element and a peripheral edge portion of the second optical element, and wherein the optical element unit has, between the first optical element and the second optical element which are bonded to each other, a hollow portion formed on an inner side of the peripheral edge portion.
  2. The optical element unit according to claim 1, wherein the bonding portion is an inorganic film formed by solid-phase bonding between an inorganic layer provided at the peripheral edge portion of the first optical element and an inorganic layer provided at the peripheral edge portion of the second optical element.
  3. The optical element unit according to claim 2, wherein the inorganic film includes at least one selected from the group consisting of a metal film, an oxide film, a nitride film, and a fluoride film.
  4. The optical element unit according to claim 2, wherein the inorganic film includes a dielectric film.
  5. The optical element unit according to claim 2, wherein the inorganic film includes an oxide film which contains a carbon atom and a hydrogen atom.
  6. The optical element unit according to claim 2, wherein the inorganic film contains at least one of SiO 2 , Al 2 O 3 , Nb 2 O 5 , Ta 2 O 5 , HfO 2 , MgO, Y 2 O 3 , ZrO 2 , ZnO, MgF 2 , AlF 3 , AlN, Si 3 N 4 , and SiOC.
  7. The optical element unit according to any one of claims 1 to 6, wherein the hollow portion has a humidity lower than a humidity of an atmospheric environment.
  8. The optical element unit according to any one of claims 1 to 7, wherein the bonding portion is provided in a region that is at the peripheral edge portion of the first optical element and the peripheral edge portion of the second optical element and is outside an optical effective area.
  9. The optical element unit according to any one of claims 1 to 8, wherein the hollow portion is formed at an optical axis position of the optical element unit.
  10. The optical element unit according to any one of claims 1 to 9, wherein the hollow portion has a humidity ratio of 2 g/kg or less.
  11. The optical element unit according to any one of claims 1 to 10, further comprising a dielectric film between the bonding portion and at least one of the first optical element and the second optical element.
  12. The optical element unit according to any one of claims 1 to 11, wherein the bonding portion extends between the hollow portion and at least one of the first optical element and the second optical element.
  13. The optical element unit according to any one of claims 1 to 12, wherein the bonding portion has a thickness of 0.1 nm or more and less than 1 µm.
  14. The optical element unit according to any one of claims 1 to 13, wherein the hollow portion has a pressure that is equal to or less than an atmospheric pressure.
  15. The optical element unit according to any one of claims 1 to 14, further comprising a third optical element, wherein the second optical element and the third optical element are bonded to each other through intermediation of a bonding portion formed by solid-phase bonding of another inorganic substance between the peripheral edge portion of the second optical element and a peripheral edge portion of the third optical element.
  16. The optical element unit according to claim 15, wherein the optical element unit has, between the second optical element and the third optical element which are bonded to each other, another hollow portion formed on the inner side of the peripheral edge portion.
  17. An optical apparatus comprising: a plurality of optical components including the optical element unit of any one of claims 1 to 16; and a holding component for holding the plurality of optical components.
  18. A manufacturing method for an optical element unit of manufacturing an optical element unit, the manufacturing method comprising: preparing a first optical element and a second optical element in which an inorganic layer is provided in a region including a peripheral edge portion of a surface on a bonding side of at least one of the first optical element and the second optical element; and solid-phase bonding the peripheral edge portions of the first optical element and the second optical element which are prepared so that a hollow portion is formed between the first optical element and the second optical element on an inner side of the peripheral edge portion.
  19. The manufacturing method according to claim 18, wherein the bonding is performed in vacuum.
  20. The manufacturing method according to claim 18 or 19, wherein the preparing includes: arranging the first optical element and the second optical element in an apparatus; and forming inorganic layers in regions including the respective peripheral edge portions of the first optical element and the second optical element which are arranged.

Description

TECHNICAL FIELD The present disclosure relates to an optical element unit in which a plurality of optical elements are combined. BACKGROUND An optical element unit in which a plurality of optical elements including lenses, mirrors, filters, sensors, and the like are combined and integrated is widely used in a camera, a telescope, a microscope, and a camera of a portable electronic product, and even in an image sensor module. In recent years, in order to enhance the imaging performance of the optical element unit, there have been demands for the optical elements to be unified with a high positional accuracy. In Japanese Patent Laid-Open No. 2007-195167, in order to perform highly-accurate imaging control and obtain an excellent-quality image in an image sensor module, at the time of bonding lenes or bonding a lens to an image sensor chip, a plurality of spacers are provided between bonding layers to improve the positional accuracy. In Japanese Patent Laid-Open No. 2005-292441, as a manufacturing method for an optical element unit in which two or more transparent resin lenses are caused to adhere to each other, there is disclosed a method involving using a lens containing an infrared absorbing agent as at least one of the transparent resin lenses, and irradiating a bonding portion with infrared rays to weld and bond the lens to the other lens. SUMMARY The present disclosure is directed to providing an optical element unit having a high environmental resistance and a good optical characteristic. The present disclosure in its first aspect provides an optical element unit as specified in claim 1. Optional features are specified in claims 2 to 16. The present disclosure in its second aspect provides a manufacturing method for an optical element unit of manufacturing an optical element unit as specified in claim 18. Optional features are specified in claims 19 to 21. The present disclosure in its third aspect provides an optical apparatus as specified in claim 17. According to the present disclosure, it is possible to provide a technology advantageous in achieving an optical element unit having a high environmental resistance and a good optical characteristic. Features of the present disclosure will become apparent from the following description of embodiments with reference to the attached drawings. The following description of embodiments is described by way of example. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view of an optical element unit according to the present disclosure.Fig. 2A is a schematic view for illustrating an example of an inorganic film for bonding optical elements in the present disclosure.Fig. 2B is a cross-sectional view for illustrating an example of the optical element unit according to the present disclosure.Fig. 2C is a schematic view for illustrating an example of an inorganic film of the optical element unit in the present disclosure.Fig. 2D is a schematic view for illustrating another example of the inorganic film for bonding the optical elements in the present disclosure.Fig. 2E is a cross-sectional view for illustrating another example of the optical element unit according to the present disclosure.Fig. 2F is a schematic view for illustrating another example of an inorganic film of the optical element unit in the present disclosure.Fig. 3 is a schematic view for illustrating an optical element unit including an anti-reflection film in the present disclosure.Fig. 4 is a cross-sectional SEM image of an optical element unit obtained by bonding by an inorganic film in the present disclosure.Fig. 5A is a schematic view of a vacuum film-forming apparatus in the present disclosure.Fig. 5B is a top view of an optical element (506) and a blocking plate (507).Fig. 6A is a schematic view for illustrating a cross section of a bonding apparatus in the present disclosure.Fig. 6B is a schematic view for illustrating a state of the bonding apparatus in the present disclosure as viewed from the top.Fig. 7A is a schematic view for illustrating a cross section of a vacuum film-forming bonding apparatus in the present disclosure.Fig. 7B is a schematic view for illustrating a state of the vacuum film-forming bonding apparatus in the present disclosure as viewed from the top.Fig. 8 is a schematic view for illustrating an example of an optical apparatus according to the present disclosure. DESCRIPTION OF THE EMBODIMENTS An embodiment of the present disclosure is described below with reference to the drawings. In the following description and the drawings, a component common to a plurality of drawings is denoted by a common reference symbol. Accordingly, common components are described with reference to the plurality of drawings mutually, and description of the components denoted by the common reference symbols is omitted as appropriate. In bonding using an adhesive, the adhesive contracts at the time of curing, and it is thus difficult to increase the positional accuracy. Furt