JP2015021999A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an alignment position of a marginal contact aligned so as to align an optical axis, and further an optical element held by a pressure ring from varying because holding of the pressure ring does not function due to expansion of a barrel with respect to the optical element under a high temperature environment.SOLUTION: Between edge surfaces of optical element rings to be abutted at a marginal contact, an elastic ring-like member, of which a dimension is set to resist abutting of the marginal contact, is arranged and is pressed by the pressure ring to thereby cause marginal contact. When a barrel expands under a high temperature environment and an air gap is about to generate between the pressure ring and the optical element, urging force of a ring-like elastic member pushes the optical element to an abutting joint surface and thereby holds an alignment position.

Description

  The present invention relates to a lens barrel having a structure for performing coaxial adjustment of a plurality of optical elements.

  Conventionally, when an optical element is held in a lens barrel, coaxial adjustment with other optical elements is sometimes performed in order to ensure optical performance.

  In Patent Document 1, the taper surface provided in the optical element is held by the taper surface of the receiving surface of the lens barrel or the taper surface of the presser ring, thereby performing coaxial and alignment with the lens barrel.

  However, when placed in a high temperature environment after coaxial adjustment, the optical element presser in the direction of the optical axis floats due to the difference in temperature expansion due to the difference in material between the lens barrel member and the optical element, making it impossible to maintain the position of the optical element. There is a problem.

  Therefore, in Patent Document 2, an abutting member provided with an inclined surface on the abutting surface side of the optical element to the lens barrel and having an inclined surface that slides on the lens barrel abutting surface with the inclined portion of the optical element is referred to as an elastic member. Is arranged through. Even if temperature expansion occurs between the lens barrel and the optical element in a high temperature environment while maintaining the optical axis position of the optical element, the inclined surface of the abutting member always urges the inclined surface of the optical element. Therefore, the optical axis shift can be prevented.

JP 2010-134378 A JP-A-7-209567

  However, in the configuration shown in Patent Document 2, since it is not possible to align the fitting backlash component existing between the lens barrel and the contact member, the fitting backlash between the lens barrel and the contact member is less than There is a problem that it cannot be applied to a lens barrel that requires high-precision optical axis holding.

  On the other hand, the configuration in which the optical element surfaces are brought into contact with each other on the outer diameter side from the effective diameter of the optical element to guarantee the interval between the optical elements is generally referred to as marginal contact. There is generally a lens fixing method in which elements are assembled and fixed to a lens barrel at the same time. Further, a place where two optical elements are in contact is referred to as a marginal point.

  In a lens barrel that holds an optical element that is brought into contact with a marginal contact, one optical element that can directly hold a curvature surface or an inclined surface with a presser ring can be kept in contact with the back side even if it can maintain a coaxial position. With respect to the other optical element, the coaxial position cannot be maintained. That is, even if the backlash between the contact member and the lens barrel can be ignored by the means proposed in Japanese Patent Laid-Open No. 7-209567, it cannot be applied to the optical element that is contacted by the marginal contact.

  Normally, the lens barrel part and the optical element have different temperature expansion coefficients depending on the material, so that the press state in the optical axis direction is released under a high temperature environment. Even if the optical element abutted by the marginal contact can be adjusted and held in a coaxial position by any means, if gravity is applied in the direction perpendicular to the optical axis in the high temperature environment, The optical element may fall in the direction of gravity and the position may change. There is a problem that there is a possibility that the initial adjustment position may not be restored even when the temperature returns to the room temperature.

  For example, when a lens barrel assembled in a room temperature of 20 ° C. is left in a high temperature environment of about 60 ° C., if the material of the lens barrel is made of a metal material such as aluminum or magnesium, the temperature of the glass Due to the difference in expansion, the presser ring may be lifted near 10 μm. In particular, holding an optical element with a marginal contact means that a plurality of optical elements are held simultaneously with a presser ring, and the distance in the optical axis direction becomes large. Therefore, a difference in temperature expansion between the lens barrel and the optical element at a high temperature. The amount of voids due to this also increases. Accordingly, the amount of fluctuation increases, and the influence on the optical performance cannot be ignored.

  In order to solve the above-mentioned problems, in the present invention, the position of the optical element abutted by the marginal contact can be adjusted with respect to the lens barrel, and a difference in temperature expansion between the optical element and the lens barrel has occurred. In particular, an excellent optical element holding method is provided.

  In order to achieve the above object, in the present invention of claim 1, two optical elements abutted by the marginal contact, a lens barrel holding the optical element, and two or more abutted by the marginal contact are provided. A holding ring that holds the optical element in the optical axis direction, and an annular elastic member centered on the optical axis that is disposed on the outer peripheral side of the marginal point of the two optical elements and on the inner periphery of the barrel The annular elastic member is larger than the distance in the optical axis direction on the outer peripheral side of the marginal point of the two optical elements, and is deformed by being pressed. Even if there is a difference in temperature expansion between the lens barrel and the optical element after the adjustment, the optical element is biased to the lens barrel contact surface by the repulsive force of the annular elastic member, so I was able to hold it stably Than is.

  The lens according to claim 1, wherein an outer peripheral side of a marginal point of at least one of the two optical elements is a tapered surface, and an annular elastic member is disposed on the tapered surface. By using the lens barrel, the force that attempts to expand the annular elastic member to the outer peripheral side simultaneously with the contact of the two optical elements with the marginal contact also works, and the repulsive force of the annular elastic member is applied to the optical element more efficiently. The sex position can be maintained.

  Further, in claim 3, the annular elastic member is in contact with each optical element on the outer peripheral side of the marginal point of the two optical elements, and further with the inner peripheral surface of the lens barrel. By adopting the lens barrel, the two optical elements are brought into contact with the marginal contact, and at the same time, the annular elastic member is expanded to the outer peripheral side, and further, the second optical element is brought into contact with the inner periphery of the lens barrel to generate a repulsive force from the inner periphery of the lens barrel. Therefore, the optical element can be held more stably.

  According to a fourth aspect of the present invention, the annular elastic member is formed of a material to which a low friction material is added. Even when placed and compressed, the optical element slides on the ring-shaped elastic member so that alignment by the presser ring is not hindered.

  Further, in claim 5, the annular elastic member is subjected to a low friction treatment, and the lens barrel according to claim 1, 2, 3 is arranged between the optical elements and compressed. In some cases, the optical element slides on the ring-shaped elastic member so as not to prevent alignment by the presser ring.

  According to the present invention, in a lens barrel that simultaneously holds a plurality of optical elements with a marginal contact, even if a temperature expansion difference occurs between the lens barrel and the optical element in a high temperature environment, the position of the optical element is stably maintained. It is possible to realize a lens barrel that can be used.

Sectional view of a lens barrel embodying the present invention Partial enlarged sectional view of FIG. 1 is an exploded perspective view of a lens barrel embodying the present invention. Sectional drawing which showed the assembly procedure of the lens-barrel which implemented this invention (the 1) Sectional drawing which showed the assembly procedure of the lens-barrel which implemented this invention (the 2) Sectional drawing which showed the assembly procedure of the lens-barrel which implemented this invention (the 3)

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  1 is a cross-sectional view of a lens barrel embodying the present invention, FIG. 2 is an enlarged cross-sectional view of a G2 and G3 contact portion of FIG. 1, and FIG. 3 is an exploded perspective view of the lens barrel embodying the present invention. These are sectional views showing the assembly procedure of the lens barrel embodying the present invention.

  1, 2, 3, and 4, G1, G2, and G3 are optical elements made of a glass material, and G2 and G3 are marginal contacts and the optical elements are in contact with each other. A lens barrel 4 for holding each optical element is made of a metal material. Reference numeral 5 denotes a first presser ring that is held by screw connection for fixing the optical element G1 to the lens barrel 4, and reference numeral 6 denotes a second presser screw that is similarly screwed to hold the optical elements G2 and G3 at the same time. It is a ring. Further, the lens barrel 4 is provided with screw holes 4a penetrating the outer peripheral portion at positions located on the outer diameter portion of the optical element G3, equally at four positions on the entire circumference.

  In addition, annular sheet materials 10 and 11 for adjusting the distance are arranged between the optical element barrel portion of the lens barrel 4 and the optical elements G1 and G3.

  Further, on the outer diameter side of the marginal point of the optical elements G2 and G3, an annular elastic member 8 made of silicon rubber is disposed at the center of the optical axis so as to be compressed by the R2 surface of G2 and the chamfered portion of G3. That is, the thickness in the optical axis direction of the annular elastic member 8 is set to be thicker than the dimension in the optical axis direction on the outer diameter side from the marginal point of the optical elements G2 and G3. It is deformed by being properly arranged in the cylinder. In other words, the annular elastic member 8 generates a repulsive force in a direction to separate the optical elements G2 and G3 which are marginally contacted. Further, the annular elastic member 8 has a low friction surface with a fluororesin added to the molding material.

  Next, a process of holding the optical element in the lens barrel 4 will be described with reference to a sectional view 4 showing an assembling procedure of the lens barrel embodying the present invention. First, in FIG. 4A, the optical element G3 is inserted into the lens barrel 4 together with the sheet member 11, and then the temporary presser tool 12 is transferred into the screw portion for the second presser ring 6 of the lens barrel 4 in this state. The optical element G3 is held in the lens barrel 4. At this time, the inclined surface of the temporary pressing tool 12 is brought into contact with the inclined surface 3a of the optical element G3, and the optical element G3 is aligned with the center of the optical axis of the lens barrel 4 by the alignment operation by the screw. Next, a set screw 9 is inserted into the screw hole 4b of the lens barrel 4 from the outer peripheral direction to fix the position of the optical element G3 in the eccentric direction.

  Next, in FIG. 4B, the temporary pressing tool 12 is removed from the lens barrel 4 from this state, and the annular elastic member 8 is disposed on the chamfered portion on the outer diameter side of the marginal point with G2 of the optical element G3. Further, the optical element G2 is inserted into the lens barrel 4 so as to come into contact with G3, and the second presser ring 6 is retracted while compressing the annular elastic member 8 so as to sandwich the optical element G2, and the optical elements G2 and G3 are simultaneously held. At this time, the optical element G2 and the contact surface of the second presser ring 6 come into contact with each other, so that the optical element G2 is aligned with the center of the optical axis of the lens barrel 4 by the aligning action of the screw, and is annular. The second presser ring 6 is carried until the elastic member 8 is compressed and the optical elements G2 and G3 come into contact with each other.

  At this time, since the fluororesin is added to the molding material in the annular elastic member 8 and the surface has low friction and the slidability is good, the centering property of the screw of the second presser ring 6 of the optical element G2 is good. Does not interfere with the alignment operation. Further, when the annular elastic member 8 is compressed between the optical elements G2 and G3, the annular elastic member 8 itself easily moves so that the urging force is equalized.

  Furthermore, the annular elastic member 8 is deformed by being sandwiched between the optical elements G2 and G3, expands to the outer diameter side, and also contacts the inner diameter portion of the lens barrel 4. Due to this deformation operation, the annular elastic member 8 abuts on the three points of the optical elements G2 and G3 and the lens barrel 4 on the cross section, so that the alignment position of G3 can be held more stably.

  After the optical elements G2 and G3 are simultaneously held by the second presser ring 6, if the set screw 9 that holds the position of the eccentric direction of G3 is still tightened, G3 will cause surface distortion and deteriorate the optical performance. Remove to make it happen.

  Next, in FIG. 4C, similarly to the optical element G 1, G 1 is inserted together with the sheet member 10 into the lens barrel 4, and the first presser ring 5 is retracted into the lens barrel 4, whereby the optical element G 1. Hold. When the polished surface 1a of G1 and the first presser ring 5 come into contact with each other, the optical element G1 is aligned with the center of the optical axis of the lens barrel 4 by the alignment operation by the screw.

  As described above, the optical axes of G2 and G3 that are in contact with the optical element G1 by the marginal contact are aligned with the optical axis center of the lens barrel 4 and can be fixedly held.

  In this state, the lens barrel is left in a high-temperature environment, and a difference in temperature expansion occurs between the lens barrel 4 and the optical elements G2 and G3, resulting in a difference between the optical element, the lens barrel, and the second presser ring. It is assumed that voids are generated. At this time, since the annular elastic member 8 urges the optical element G3 to the body-mounted surface of the lens barrel 4, the alignment position of G3 does not move due to friction. Also, under the high temperature environment, the elastic force of the annular elastic member 8 acts in the direction in which the marginal contacts of the optical elements G2 and G3 are separated from each other. Don't be.

  Even if it is placed in a high temperature environment for a period of time, if it returns to the room temperature environment, it will return to the initial optical axis position, and the interval change itself will not occur.

  In this embodiment, the lens barrel 4 is made of a metal material. However, when the lens barrel 4 is made of a resin material, the temperature expansion difference from the optical element made of a glass material is further increased. , More effective.

  Further, in this embodiment, the annular elastic member 8 is made of a fluororesin added to the molding material and has a low friction surface, but this is a low friction after molding with a normal elastic material such as elastomer or silicon rubber. The effect is the same even if the lubrication coating process is performed.

  Furthermore, in this embodiment, the set screw 9 is attached to the penetrating tool hole 4a of the lens barrel 4 to hold the optical element G3 after alignment, and G3 is fixed. G3 may be held from the outer periphery of the lens barrel. The temporary pressing tool 12 of the optical element G3 is removed, the annular elastic members 8 and G2 are inserted, and after holding G2 and G3 by the second pressing ring 6, the tool may be removed.

  In the present embodiment, annular sheet materials 10 and 11 for adjusting the distance are arranged between the optical element barrel portion of the lens barrel 4 and the optical elements G1 and G3. The material is not a requirement of the present invention.

G1, G2, G3 ... optical element, 3a ... G3 inclined surface 4 ... lens barrel, 4a ... through screw hole 5 ... first presser ring 6 ... second presser Ring 8 ... Ring elastic member 9 ... Set screw 10 ... G1 sheet 11 ... G3 sheet 12 ... Temporary presser tool

Claims (5)

  Two optical elements in contact with the marginal contact, a lens barrel for holding the optical element, a presser ring for holding two or more optical elements in contact with the marginal contact in the optical axis direction, and the two And an annular elastic member centered on the optical axis disposed on the outer peripheral side of the marginal point of the two optical elements and on the inner periphery of the lens barrel, the annular elastic member being a marginal of the two optical elements. A lens barrel characterized by being pressed and deformed larger than the interval in the optical axis direction on the outer peripheral side of the point.   The lens barrel according to claim 1, wherein an outer peripheral side of a marginal point of at least one of the two optical elements is a tapered surface, and an annular elastic member is disposed on the tapered surface.   3. The lens barrel according to claim 1, wherein the annular elastic member is in contact with each optical element on the outer peripheral side of the marginal point of the two optical elements and further with the inner peripheral surface of the lens barrel. .   The lens barrel according to any one of claims 1 to 3, wherein the annular elastic member is formed of a material to which a low friction material is added. The lens barrel according to any one of claims 1 to 3, wherein the annular elastic member is subjected to a low friction treatment.