JP2008191280A - Lens module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical system with a lens module having a plurality of lenses in close contact with each other, which is adaptable to an environmental change such as pressure and temperature by avoiding the hermetically sealed state of space between lenses. <P>SOLUTION: In the lens module having a concave lens 2, other optical member 3 is provided so as to be in close contact with the concave curve of the concave lens. The other optical member is brought in close contact with the concave curve, on a surface whose radius of curvature is larger than that of the concave curve, to form the space 7 between the concave lens and the other optical member, and a groove 14 crossing the peripheral edge of the concave curve and leading to the space is formed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical system including a lens module configured by combining a plurality of lenses, and more particularly to an optical system used in an optical apparatus used in an environment where atmospheric pressure changes and temperature changes are large.

  The environment in which optical devices such as a telescope mounted on an artificial satellite, an imaging device installed in a vacuum test room, and a camera used for polar observation are used has extremely large changes in atmospheric pressure and temperature. For this reason, the lens module which is one of the components of the optical system of these optical devices is required to have a structure that can cope with a large change in atmospheric pressure and temperature. In addition, a telescope or the like mounted on an artificial satellite needs to be as small and light as possible, and the lens module is required to be small and light.

  A conventional lens module will be described with reference to FIG.

  FIG. 10 shows a lens module 1 having a concave lens 2 and a convex lens 3. The concave lens 2 and the convex lens 3 are held by a lens barrel 4, and a spacing ring is provided between the concave lens 2 and the convex lens 3. 5 is provided, and a space 6 sealed by the lens barrel 4, the concave lens 2, and the convex lens 3 is formed.

  When the optical apparatus having the lens module 1 is used in an environment where the atmospheric pressure change and the temperature change are extremely large, an atmospheric pressure difference and a temperature difference are generated between the space 6 and the outside of the lens module 1. When a large atmospheric pressure difference occurs, an external pressure acts on the concave lens 2 and the convex lens 3, which causes an optical axis shift between the concave lens 2 and the convex lens 3. Further, when a large temperature difference or atmospheric pressure difference occurs, the water vapor enclosed in the space 6 causes fogging, which causes a reduction in lens performance.

  The lens module 1 shown in FIG. 10 has a structure in which the concave lens 2 and the convex lens 3 are fitted into the lens barrel 4, and there is a slight gap between the concave lens 2 and the convex lens 3 and the lens barrel 4. There is a gap. Even if there is a pressure difference or a temperature difference between the space 6 and the outside of the lens module 1, the space 6 and the outside of the lens module 1 have gas in and out through a slight gap. Is resolved.

  Further, when the lens module 1 is required to be small and light, as shown in FIG. 11, the spacing ring 5 is omitted and the concave lens 2 and the convex lens 3 are in close contact with each other. The

  Even when the concave lens 2 and the convex lens 3 are in close contact with each other, a space 7 is formed between the concave lens 2 and the convex lens 3 due to the difference in curvature of the curved surfaces of the concave lens 2 and the convex lens 3. The space 7 is a completely sealed space, and when the lens module 1 is placed in an environment where the atmospheric pressure change and the temperature change are significantly large, there is a pressure difference between the space 7 and the outside of the lens module 1. A temperature difference and a humidity difference are generated. In particular, the pressure difference and the humidity difference are not eliminated even after a lapse of time, and there is a possibility that an optical axis shift due to an internal / external pressure difference and clouding due to dew condensation of water vapor may occur.

  When the lens module 1 is manufactured, it can be considered that the lens module 1 is assembled in a vacuum chamber or in a dry nitrogen gas environment. However, special equipment is required and the cost is increased.

JP 2005-249994 A

  In view of such circumstances, the present invention avoids the sealed state of the space formed between the lenses in a lens module having a structure in which a plurality of lenses are in close contact, and can be adapted to environmental changes such as atmospheric pressure changes and temperature changes. A lens module is provided.

  According to the present invention, in a lens module having a concave lens, another optical member is provided in close contact with the concave curved surface of the concave lens, and the other optical member has a surface with a larger radius of curvature than the concave curved surface. The present invention relates to a lens module in which a space is formed between the concave lens and the other optical member in close contact with a curved surface, and a groove is formed across the periphery of the concave curved surface and communicating with the space.

  Further, the present invention relates to a lens module in which an edge portion is formed around the concave curved surface of the concave lens, the groove has one end opened to the concave curved surface, and the other end opened to the outer peripheral surface, and the concave lens is An edge portion is formed around a concave curved surface, the groove is related to a lens module formed in a ridge line portion formed by the concave curved surface and the edge portion, and the groove is engraved in the other optical member, A lens module provided so as to traverse a portion where a peripheral edge of a concave lens abuts, and a side groove is formed in one of the concave lens and the other optical member, and the side groove communicates with the groove. Further, the side groove is related to a lens module that is inclined with respect to the generatrix of the outer peripheral surface.

  According to the present invention, in a lens module having a concave lens, another optical member is provided in close contact with the concave curved surface of the concave lens, and the other optical member has a surface with a larger radius of curvature than the concave curved surface. A space is formed between the concave lens and the other optical member in close contact with the concave curved surface, and a groove that crosses the periphery of the concave curved surface and communicates with the space is formed. The space between the lenses formed in this case communicates with the outside through a groove, and can be adapted to environmental changes such as atmospheric pressure changes and temperature changes.

  Further, according to the present invention, a side groove is formed in one of the concave lens and the other optical member, and the side groove communicates with the groove. Therefore, even when the lens is held by the holding means, The space and the outside of the lens module communicate with each other via a groove and a side groove, so that quick adaptation to environmental changes such as atmospheric pressure change and temperature change is possible.

  Furthermore, according to the present invention, since the side groove is inclined with respect to the bus bar on the outer peripheral surface, an excellent effect such as suppression of rattling caused by the groove being formed can be exhibited.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  The first embodiment will be described with reference to FIGS. In FIG. 1, the lens barrel is omitted.

  The lens module 11 shown in FIG. 1 has the left side as the object side and the right side as the imaging side.

  The lens module 11 is held by a lens barrel (not shown) in a state where the concave lens 2 and the convex lens 3 are in close contact with each other, the object side of the concave lens 2 is a concave surface having a large radius of curvature, and the concave lens On the image forming side 2, a concave lens effective portion 12 having a small radius of curvature and an edge portion 13 that does not contribute to refraction are formed at the peripheral portion.

  The convex lens 3 provided in close contact with the concave lens 2 has a convex surface whose object side surface has a radius of curvature larger than the radius of curvature of the lens effective portion 12, and a space 7 is formed between the concave lens 2 and the convex lens 3. Is done.

  A groove 14 extending in the radial direction is formed in the edge portion 13 of the concave lens 2 in at least one place. The groove 14 has one end opened to a concave curved surface, the other end opened to the outer peripheral surface, and communicates the space 7 and the outer peripheral portion of the concave lens 2 to make the space 7 open.

  Even if an atmospheric pressure change or a temperature change occurs in an environment in which the lens module 11 is placed, there is a circulation between the space 7 and the atmosphere around the lens module 11 through the groove 14. There is no pressure difference, temperature difference, or humidity difference between the lens module 11 and the outside. Accordingly, it is possible to prevent the occurrence of misalignment of the optical axis due to the difference between the internal and external pressures and clouding due to the condensation of water vapor.

  3 and 4 show a second embodiment.

  In the second embodiment, a groove 14 is formed in a ridge line portion 15 formed at the boundary between the lens effective portion 12 and the edge portion 13. Even when the groove 14 is formed in the ridge line portion 15, the space 7 communicates with the outer peripheral portion of the concave lens 2.

  5 and 6 show a third embodiment.

  A groove 14 extending in the radial direction is formed in the edge portion 13 of the concave lens 2, and a spiral side groove 16 (inclined with respect to the generatrix) is formed on the outer peripheral surface of the concave lens 2, and the side groove 16 and the groove 14 are formed. Are communicated with each other. The groove 14 does not necessarily have to coincide with the radial direction.

  By providing the side groove 16, the outside of the lens module 11 and the space 7 (see FIG. 1) are communicated by the side groove 16 and the groove 14 even when the concave lens 2 is held by the lens barrel. The space 7 is equalized and isothermal with respect to the outside of the lens module 11 even when there is a significant pressure fluctuation or temperature fluctuation.

  The side groove 16 may be formed on the outer surface of the lens in which the groove 14 is not provided, or in the third embodiment, the convex lens 3. In short, it is only necessary that the side groove 16 continues to the groove 14 as a space.

  In addition, by inclining the side groove 16 with respect to the bus bar, the side groove 16 appears only in a part of the cross section as seen in FIG. Therefore, by engraving the side groove 16, the concave lens 2 does not rattle the holding means such as the lens barrel.

  Here, when the side groove 16 is engraved along the generatrix, the radius of the portion where the side groove 16 is engraved is reduced by Δr as shown in FIG.

  Although the side groove 16 is only inclined, the occurrence of rattling can be reduced. Preferably, the amount of inclination of the side groove 16 is shifted by more than ½ of the groove width in the circumferential direction at the start and end of the side groove 16. It only has to be. By shifting by 1/2 or more, there is no backlash caused by the grooves.

  FIG. 9 shows a fourth embodiment.

  In the fourth embodiment, at least one groove 17 extending in the radial direction is formed in a portion where the ridge line portion 15 of the convex lens 3 contacts. Even when the groove 17 is formed in the convex lens 3, the side groove 16 may be formed on the outer peripheral surface of the convex lens 3 and communicated with the groove 17 as in the third embodiment.

  In addition to the combination of the concave lens 2 and the convex lens 3, the present invention can be applied to a combination of the concave lens 2 and an optical member having a flat plate shape (the radius of curvature is infinite) such as a filter and a cover glass. Not long.

It is sectional drawing which shows the principal part of the 1st Embodiment of this invention. It is a perspective view of the concave lens used for 1st Embodiment same as the above. It is a perspective view of the concave lens used for 2nd Embodiment same as the above. It is sectional drawing of this concave lens. It is a perspective view of the concave lens used for 3rd Embodiment same as the above. It is sectional drawing of this concave lens. It is sectional drawing of the groove part of this concave lens. It is a top view of the groove part of this concave lens. It is sectional drawing which shows the principal part of the 4th Embodiment of this invention. It is sectional drawing which shows the principal part of the conventional lens module. It is sectional drawing which shows the principal part of the other conventional lens module.

Explanation of symbols

2 Concave lens 3 Convex lens 4 Lens barrel 7 Space 11 Lens module 12 Lens effective part 13 Edge part 14 Groove 15 Edge line part 16 Side groove

Claims (6)

  In a lens module having a concave lens, another optical member is provided in close contact with the concave curved surface of the concave lens, and the other optical member is in close contact with the concave curved surface at a surface having a larger radius of curvature than the concave curved surface. The lens module is characterized in that a space is formed between the concave lens and the other optical member, and a groove is formed across the periphery of the concave curved surface and communicating with the space.   The lens module according to claim 1, wherein the concave lens has an edge formed around the concave curved surface, and the groove has one end opened to the concave curved surface and the other end opened to the outer peripheral surface.   2. The lens module according to claim 1, wherein an edge portion is formed around the concave curved surface of the concave lens, and the groove is formed at a ridge line portion formed by the concave curved surface and the edge portion.   The lens module according to claim 1, wherein the groove is formed in the other optical member so as to cross a portion where a peripheral edge of the concave lens contacts.   The lens module according to claim 1, wherein a side groove is formed in one of the concave lens and the other optical member, and the side groove communicates with the groove.   The lens module according to claim 5, wherein the side groove is inclined with respect to a generatrix of the outer peripheral surface.

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