JP2019028319A - Lens device and imaging apparatus having the same - Google Patents

Abstract

To provide a lens device capable of preventing dew condensation without requiring electric power in a configuration that reduces the frequency of maintenance.SOLUTION: The lens device includes an optical member, an optical holding member holding the optical member, and an exterior member covering the optical holding member, and the lens device has thermal conduction means capable of conducting external heat of the lens device to the optical member via the exterior member. The heat conduction means switches between a conduction state where the means deforms in response to one of or both of the external temperature of the lens device and the temperature of the optical member so as to conduct the external heat to the optical member and a non-conduction state where the means does not conduct heat.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a lens device and an imaging device having the lens device.

  The lens device is also used in an environment in which the temperature outside the lens device suddenly rises, for example, when the lens device is moved from a cooled room to the outside. In such a case, there is a problem that the lens is condensed and cloudy.

  When the external temperature of the lens apparatus rapidly increases, a pressure difference is generated inside and outside the lens apparatus, and high temperature outside air flows in the vicinity of the lens. If the lens is not sufficiently warmed at this time, the surface of the lens becomes lower than the dew point temperature of the outside air, and condensation occurs.

  The dew point temperature is a temperature at which water vapor in the air begins to condense when cooling air in a space where the amount of water vapor is constant. If the temperature is higher than the dew point temperature, condensation does not occur, and if it is lower, condensation occurs.

  In particular, in a lens device having a cover that can be attached to and detached from the lens device, a space is provided between the cover and the lens device for attachment and detachment. Since this space becomes a heat insulating layer between the outside of the cover and the lens, the heat of the outside air is more difficult to transfer to the lens, and condensation is likely to occur.

  Conventionally, a method of heating or keeping a temperature of a lens is known. In patent document 1, the structure which heats glass with a heater is disclosed. Also known is a method of reducing the dew point temperature by installing a desiccant or enclosing dry air to reduce the amount of water vapor in the lens device, thereby increasing the lens temperature margin with respect to the dew point temperature. Patent Document 2 discloses a technique for filling a lens device with a desiccant to reduce the amount of water vapor.

JP 2007-256849 A JP-A-6-258561

  However, the configuration disclosed in Patent Document 1 has a problem of increasing power consumption because it generates heat using electric power.

  In the configuration disclosed in Patent Document 2, since it is necessary to periodically replace the desiccant, there is a problem that burdens the user in terms of maintenance.

  Accordingly, an object of the present invention is to provide a lens apparatus that prevents condensation without using electric power and further reduces the maintenance frequency.

  In order to achieve the above object, the present invention provides a lens device that includes an optical member, an optical holding member that holds the optical member, and an exterior member that covers the optical holding member. Heat conduction means capable of conducting heat outside the lens device to the optical member, and the heat conduction means is deformed according to one or both of the temperature outside the lens device and the temperature of the optical member. And switching between a conduction state in which the external heat is conducted to the optical member and a non-conduction state in which the heat is not conducted.

  According to the present invention, it is possible to provide a lens apparatus that prevents condensation without using electric power and further reduces the maintenance frequency.

Schematic of the entire lens apparatus of Example 1 Schematic diagram of part A (heat conduction means) in FIG. Schematic which shows operation | movement of the heat conduction means in each use environment of Example 1. FIG. Explanatory drawing of the use environment of Example 1 The figure which shows operation | movement of the heat-transfer means in the environment of FIG. 4 in Example 1. FIG. Schematic explaining the effect of Example 1 under the environment of FIG. Schematic of the entire lens device of Example 2 Part A detail view of FIG. B direction arrow view of FIG. The figure which shows operation | movement of the 1st heat conductive part of Example 2, and the 2nd heat conductive part. Schematic of the entire lens apparatus of Example 3 Detailed view of part C in FIG. Schematic of the entire lens apparatus of Example 4 E section enlarged view of FIG. D direction view of FIG. 15

  Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example 1
First, a first embodiment of the present invention will be described with reference to FIGS.

(Configuration of lens device)
First, based on FIG. 1 and FIG. 2, the structure of the lens apparatus L1 of this invention is demonstrated. FIG. 1 is an overall schematic diagram of the present embodiment. A part of FIG. 1 shows an internal structure of the lens device L1. FIG. 2 is a schematic view of part A of FIG.

  The lens barrel 2 holds the lens 3 by a presser ring 8 and is connected to an outer holding member (exterior member) 1 with screws 7.

  The lens apparatus in the present embodiment is a zoom lens having each lens group including a focus group including the lens 3 from the subject side, a variator group (not shown), a compensator group (not shown), and a relay group (not shown). The configuration of the lens device is not limited to this. The lens 3 may be a lens other than the focus group.

  In addition, although the lens 3 of a present Example is comprised with glass, even if it is a lens comprised with resin, the effect of this invention can be acquired.

  As shown in FIG. 2, a groove 40 is formed inside the outer holding member 1 in the radial direction with respect to the optical axis. Similarly, a groove 50 is formed outside the lens barrel 2 in the radial direction. These grooves 40 and 50 are opposed to each other, and heat conduction means to be described later is attached.

(Configuration of heat conduction means)
As shown in FIG. 2, the heat conducting means in the present embodiment includes a first heat conducting unit 4 and a second heat conducting unit 5 having a plate shape.

  The first heat conducting unit 4 is attached to the outer holding member 1 by screws 6 passing through the long holes 4c formed at both ends. The second heat conducting unit 5 is attached to the lens barrel 2 by screws 6 passing through the long holes 5c formed at both ends.

  With this configuration, the first heat conducting unit 4 and the second heat conducting unit 5 are free to expand and contract in the longitudinal direction (in the present embodiment, the optical axis direction in the present embodiment, and in the direction of arrow F in FIG. 2). Have a degree.

(First heat conduction part)
The first heat conducting unit 4 includes a first member 4a and a second member 4b having different coefficients of thermal expansion. The coefficient of thermal expansion of the first member 4a is greater than the coefficient of thermal expansion of the second member 4b. In the 1st heat conductive part 4, the 2nd member 4b is affixed on the area | region of the both ends of the 1st member 4a in the thickness direction of a board. In this embodiment, these materials are metals, and a known technique such as cold rolling can be used for attaching these materials. Such a configuration in which two metal plates having different coefficients of thermal expansion are attached is generally called a bimetal element. The metal used for a bimetal element can be arbitrarily selected according to the use, for example, alloys, such as a nickel alloy and a copper alloy, are used.

  When the temperature of the first heat conducting unit 4 rises, the first member 4a having a relatively large coefficient of thermal expansion expands more than the second member 4b. At this time, since these members are bonded to each other and deformation is restrained, the first heat conducting portion 4 has a plate material (second member 4b) having a smaller coefficient of thermal expansion with respect to the optical axis. It is deformed (curved) so as to be convex inward of the direction. The deformation temperature can be set to a predetermined temperature (first temperature) by selecting the material of the first member 4a and the second member 4b from known materials as described above.

  FIG. 2 shows a state where the first heat conducting unit 4 is deformed so as to protrude inward in the radial direction with respect to the optical axis.

(Second heat conduction part)
Similarly to the first heat conducting unit 4, the second heat conducting unit 5 includes a first member 5a and a second member 5b having different coefficients of thermal expansion. The thermal expansion coefficient of the first member 5a is smaller than the thermal expansion coefficient of the second member 5b.

  Similarly, the second heat conducting portion 5 which is a bimetal element is deformed so that the first member 5a having a relatively low coefficient of thermal expansion is located inside when the temperature exceeds a predetermined temperature. However, in the present embodiment, the second heat conducting portion 5 is deformed in advance so as to protrude toward the outer holding member 1 (first heat conducting portion 4) in an environment lower than a predetermined temperature. It is attached in the state. The state of the second heat conducting unit 5 shown in FIG. 2 shows a state of being deformed in advance at a temperature lower than a predetermined temperature.

  With this configuration, when the second heat conducting unit 5 reaches a temperature higher than a predetermined temperature (second temperature), the first heat conduction unit 5 cancels the bending from the previously bent state. The member 5a is deformed inward (conversely curved). Thereby, it will contact | adhere to the lens-barrel 2 (it will be in the state shown to FIG.5 (c) (d)). The first member 5a does not need to be in close contact with the lens barrel 2, and the present invention can be implemented as long as the first member 5a is separated from the first member 4a in the first conductive member 4.

(Combination of first and second heat conduction parts)
In the present embodiment, both the first heat conducting unit 4 and the second heat conducting unit 5 are configured such that a member having a relatively large coefficient of thermal expansion is on the lens 3 side. That is, both the first heat conducting unit 4 and the second heat conducting unit 5 are deformed to the lens 3 side when their own temperature becomes higher than a predetermined temperature.

  However, in this embodiment, a combination of both an uncurved state and a pre-curved state is used in an environment below a predetermined temperature. With these combinations, the heat conducting means in the embodiment can take the state shown in FIG. 3 according to the temperature.

  FIG. 3 schematically shows the operation of the heat conducting means in each environment. The region marked with H shows that the temperature is higher than the predetermined temperature, and the region marked with L is higher than the predetermined temperature. Also shows that the temperature is low.

  As shown in FIG. 3A, when the temperature relationship of (the first heat conducting unit 4 and the second heat conducting unit 5) is (L, L), the components are separated from each other. Has been. In this state, the heat conduction means does not form a heat conduction path between the outer holding member 1 and the lens 3. This state is referred to as a nonconductive state.

  As shown in FIG. 3B, in the case of (H, L), the central region of the first heat conducting unit 4 that exceeds a predetermined temperature is convex toward the lens 3 side. Bend. On the other hand, the second heat conducting portion 5 is curved so that the central region thereof is convex toward the outer holding member 1 in advance, so that the convex portions face each other and come into contact with each other.

  That is, when the first heat conducting part 4 and the second heat conducting part 5 constituting the heat conducting means are in contact with each other, a heat conduction path is formed in the outer holding member 1 and the lens barrel 2 connected thereto. This state is referred to as a conduction state.

  As shown in FIG. 3C, in the case of (H, H), the second heat conducting part 5 is deformed in a direction to cancel the pre-curvature, and thus does not contact each other. As shown in FIG. 3D, in the case of (L, H), the first heat conducting part 4 is not curved, and the second heat conducting part 5 is canceled in advance, Do not touch. These are all in the non-conductive state described above.

(Construction conditions of heat conduction means)
Each predetermined temperature in each heat conducting means is preferably between 0 degrees Celsius and 60 degrees Celsius assuming a general use environment. More preferably, it is desirable to set between 10 and 20 degrees Celsius. More preferably, it is desirable to be designed to deform as described above at substantially 15 degrees Celsius (may include variations due to manufacturing errors, etc.). The predetermined temperatures (first temperature and second temperature) of the first heat conducting unit 4 and the second heat conducting unit 5 may be the same or different. In the present embodiment, a case will be described in which the predetermined temperatures of the first heat conducting unit 4 and the second heat conducting unit 5 are both 15 degrees Celsius.

  In each heat conduction part of the present embodiment, a member having a relatively high thermal expansion coefficient needs to be provided on the lens 3 side. Moreover, the material of the 1st heat conductive part 4 and the 2nd heat conductive part 5 is a member whose heat conductivity is higher than air.

(Operation of heat conduction means)
Hereinafter, the operation in this embodiment will be described with reference to FIGS. In the present embodiment, an example in which each predetermined temperature in each heat conducting means is 15 degrees will be described.

(Definition of usage conditions)
First, with reference to FIG. 4, four conditions used in the description of this embodiment are defined.

  As a first use condition E1, sufficient time has passed in an environment where the temperature outside the lens device is 0 degrees Celsius (relative humidity 0%), and the inside and outside of the lens device reach an equilibrium state (first heat A state is defined in which the temperatures of the conduction part 4 and the second heat conduction part 5) are (L, L).

  As the second use condition E2, a condition with a large temperature change is defined in which the external temperature rises to 60 degrees Celsius (a high temperature equal to or higher than the set temperature) from the first use condition E1 (relative humidity 100%).

  As the third use condition E3, a sufficient time has passed in an environment where the external temperature is 60 degrees Celsius (relative humidity 100%), and the inside and the outside of the lens apparatus reach an equilibrium state. 4. Define a state in which the temperature relationship of the second heat conducting section 5) is (H, H).

  As the fourth use condition E4, a condition with a large temperature change is defined in which the external temperature drops to around 0 degrees Celsius (relative humidity 0%) from the third use condition E3.

(Operation and effect)
5A is a diagram showing the state of the heat conducting means in each use condition of E1, FIG. 5B is E2, FIG. 5C is E3, and FIG. 5D is E4.

  In the use condition E1 shown to Fig.5 (a), the 1st heat conductive part 4 does not deform | transform but is located in the outer side holding member 1 side. The 2nd heat conductive part 5 is the state curved so that the center area | region may become convex on the outer side holding member 1 side previously. In this case, the 1st heat conduction part 4 and the 2nd heat conduction part 5 are comprised so that it may not contact. That is, the lens 3 and the outer holding member 1 become nonconductive.

  In the first use condition E1, the possibility of fogging is low. Under such conditions, it is possible to prevent the lens 3 from being cooled too much via the lens barrel 2 and adversely affecting the optical performance due to the non-conductive state of the heat conducting means.

  In the second use condition E2 shown in FIG. 5B, the first heat conducting unit 4 is connected to the outer holding member 1, and therefore absorbs the heat of the outside air through the outer holding member 1. Therefore, the second heat conducting portion 5 is deformed so that the temperature becomes a predetermined set temperature or more before the second heat conducting portion 5 and the central region is convex toward the lens 3 as shown in FIG. That is, it deforms according to the temperature outside the outer holding member 1.

  On the other hand, the second heat conducting unit 5 is slow in heat transfer and maintains a curved state toward the outer holding member 1. That is, the curvature is maintained according to the temperature of the lens 3.

  In this case, as shown in FIG. 5 (b), the first heat conducting part 4 and the second heat conducting part 5 are in contact with each other in the central region to form a heat conduction path (arrow 101). Has been. That is, the lens 3 and the outer holding member 1 are in a conductive state.

  In the conductive state, in addition to the heat conducted to the lens barrel 2 through the path indicated by the conventional arrow 100, heat is also transferred through the path indicated by the arrow 101. For this reason, possibility that the surface temperature of the lens 3 will exceed the dew point temperature inside a lens apparatus becomes high, and generation | occurrence | production of the cloudiness in the surface of the lens 3 can be suppressed.

  Further, in this embodiment, the central region (region excluding both ends) where the two kinds of metals are not bonded is in contact with the first heat conducting unit 4 and the second heat conducting unit 5. It is configured. Since the curvature of this region is small, a surface contact state can be configured. For this reason, heat can be more efficiently conducted.

  In the third use condition E3 shown in FIG. 5C, both the first heat conducting unit 4 and the second heat conducting unit 5 are equal to or higher than a predetermined set temperature. The first heat conducting unit 4 is deformed so that the central region is convex toward the lens 3 side. On the other hand, the second heat conducting unit 5 is deformed to the lens 3 side so as to cancel the pre-curvature.

  In this case, as shown in FIG.5 (c), the 1st heat conductive part 4 and the 2nd heat conductive part 5 do not contact, but the lens 3 and the outer side holding member 1 will be in a non-conductive state.

  In the third use condition E3, the possibility of fogging is low. Under such conditions, the heat conducting means is in a non-conducting state, so that it is possible to prevent the lens 3 from being warmed through the lens barrel 2 and adversely affecting the optical performance.

  In the fourth use condition E4 shown in FIG. 5D, since the first heat conducting unit 4 is connected to the outer holding member 1, heat is taken to the outside through the outer holding member 1. Therefore, the temperature becomes equal to or lower than a predetermined set temperature prior to the second heat conducting portion 5, and is deformed to the outer holding member 1 side as shown in FIG. On the other hand, the second heat conducting unit 5 is slow in heat transfer and maintains the position on the lens 3 side.

  In this case, the 1st heat conduction part 4 and the 2nd heat conduction part 5 do not contact, but the lens 3 and the outer side holding member 1 will be in a non-conductive state.

  If the lens 3 and the outer holding member 1 remain in the conductive state, and the temperature outside the outer holding member 1 rapidly decreases, the heat of the lens 3 is rapidly taken away as compared with the non-conductive state. If the temperature of the surface of the lens 3 is lower than the dew point temperature of the air in the space before the air in the space surrounded by the lens 3 and the lens barrel 2 is in an equilibrium state with the outside air, condensation starts to occur.

  Therefore, as in the present embodiment, when the external temperature is drastically lowered, the heat conduction path between the lens 3 and the outer holding member 1 is reduced by taking a non-conductive state (only the arrow 102), and the heat of the lens 3 is reduced. Prevent sudden deprivation. For this reason, the possibility that the surface temperature of the lens 3 is relatively lower than the dew point temperature can be reduced, and the occurrence of fogging on the surface of the lens 3 can be suppressed.

(effect)
With the above configuration, it is possible to keep the glass temperature of the lens apparatus higher than the dew point temperature and prevent fogging even in an environment where the temperature change is large.

  FIG. 6 shows an example of changes in the glass surface temperature and the dew point temperature inside the lens device when the temperature outside the lens device changes as described above. As shown in FIG. 6, the temperature of the lens 3 can be kept higher than the dew point temperature even when the temperature of the external environment changes. Accordingly, the number of scenes where the lens apparatus can be used increases, and convenience is improved.

  Furthermore, since the configuration is simple, the lens device can be prevented from being increased in size and weight.

  Further, since no power is required, the power consumption of the lens device does not increase, and the effect of preventing condensation can be obtained even when the lens device is not driven.

  Furthermore, in this embodiment, since the state of connection of heat conduction means is switched using the property of thermal expansion of metal, the life is long, compared with the conventional configuration such as filling with a drying material. Frequent maintenance is not required, reducing the burden on the user.

(Modification)
In the present embodiment, the configuration in which the first heat conducting unit 4 and the second heat conducting unit 5 are arranged one by one has been described. However, a plurality may be arranged. In this case, since the contact area increases, a higher heat transfer effect can be obtained.

  In the present embodiment, the configuration in which the first heat conducting unit 4 and the second heat conducting unit 5 are used facing each other has been described. However, a certain effect can be obtained even in a configuration in which either the first heat conducting unit 4 or the second heat conducting unit 5 is used and the curved portion is in direct contact with the lens barrel 2 or the outer holding member 1.

  In the case where the heat conducting means is installed only on the outer holding member 1, it is configured so as to come into contact with the lens barrel 2 when the temperature exceeds a predetermined temperature. In this case, heat transfer also occurs in the third usage environment E3. However, in this case, since the lens 3 and the exterior member 1 approach the temperature equilibrium state, it is possible to obtain a certain dew condensation suppression effect.

  On the contrary, when the heat conducting means is installed only in the lens barrel 2, it is configured to be curved so as to contact the outer holding member 1 in advance and to be able to release the contact when the temperature exceeds a predetermined temperature. . In this case, heat transfer occurs even in the first use environment E1. However, in this case as well, the lens 3 and the exterior member 1 approach a temperature equilibrium state, so that a certain dew condensation suppression effect can be obtained.

  In this embodiment, the shape of the heat conducting means has been described as a plate shape. The plate shape can be easily deformed and a contact area can be secured. However, the shape is not limited to this. For example, the heat conduction means may be configured using a rod shape, and a plurality of rod shapes may be provided so as to obtain a desired amount of heat transfer.

  In this embodiment, the heat conducting means conducts heat between the outer holding member 1 and the lens barrel 2. However, a cover may be further provided around the outer holding member 1, and a heat conducting means may be configured between the outer holding member 1 and the cover. As described above, as long as the optical member and the exterior member exposed to the outside air can conduct heat, the member that the heat conducting means contacts is not limited.

(Example 2)
Hereinafter, the lens device L2 according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a schematic view showing the entire lens apparatus L2 to which the second embodiment of the present invention is applied. Part of the inside is shown. FIG. 8 is a diagram showing the details of part B of FIG. FIG. 9 is a view in the direction of arrow B1 in FIG.

(Configuration of lens device)
Unlike the first embodiment, the present embodiment has a configuration in which the exterior member 1 is detachably attached to the lens barrel (optical holding member) 2 in the direction of the optical axis O of the lens 3. There is a space between the exterior member 1 and the lens barrel 2, and the exterior member 1 covers the entire lens barrel 2 so as to surround the optical axis O of the lens 3. In the present embodiment, as shown in FIG. 7, heat heat transfer means (first heat conducting unit 210 a and second heat conducting unit 210 b) is provided between the exterior member 1 and the lens barrel 2.

  The lens barrel 2 has an outer lens barrel 2 a provided on the exterior member 1 side and an inner lens barrel 2 b provided on the lens (optical member) 3 side, which are connected to each other by screws 7.

  Hereinafter, the same number is attached | subjected to the structure similar to Example 1, and description is abbreviate | omitted.

(Configuration of heat conduction part)
As shown in FIG. 8, the first heat conducting unit 210a includes a first contact part 211a and a first heat deforming member 212a which is a heat deforming part. One end of the first thermal deformation member 212 a is fixed to the exterior member 1 with a screw 90.

  The second heat conducting unit 210b includes a second contact part 211b and a second heat deforming member 212b as a heat deforming part. One end of the second thermal deformation member 212b is fixed by a screw 90.

  In this embodiment, thermal expansion and contraction in the direction of the optical axis O (predetermined direction) of each thermal deformation portion are used. Each thermally deformable portion is made of a material having the same linear expansion coefficient, and the length at an arbitrary temperature is set to be approximately equal. Each thermal deformation portion is deformed by thermal expansion and thermal contraction according to the temperature outside the lens device and the temperature of the optical member, and slides each contact portion.

  As shown in FIG. 8, the first heat conducting unit 210a and the second heat conducting unit 210b are fixed in a state where a predetermined interval δ is shifted in the optical axis O direction. The interval δ may be 0. Moreover, each contact part is provided with the convex shape which does not mutually overlap seeing from the optical axis O direction (refer FIG. 9). The heat conduction part is preferably made of a material having a small linear expansion coefficient.

(Operation and effect)
FIG. 10A shows a state in which the inside and the outside of the lens device L2 are balanced at an arbitrary temperature that is equal to or lower than a predetermined temperature Ts. FIG. 10B shows a state where the temperature of the exterior member 1 has increased. FIG. 10C shows a state in which the temperature inside and outside the lens device L2 is balanced beyond a predetermined temperature Ts. FIG. 10D shows a state where the temperature of the exterior member 1 is lowered.

  In the state of FIG. 10A, since the temperature of the entire lens device L2 is in a uniform equilibrium state, the expansion (thermal expansion) of the thermal deformation portion is substantially equal. For this reason, a relative relationship is maintained in which the contact portions do not contact each other with a predetermined interval δ (see FIG. 8). Thus, when the temperature difference between the exterior member 1 and the lens barrel 2 is small, the heat transfer path between them is not formed by the heat transfer means (non-conductive state).

  In the state of FIG. 10B, the temperature outside the lens device L <b> 2 increases, and the temperature of the first heat conducting unit 210 a that can absorb heat via the exterior member 1 becomes relatively high. In this case, the first heat deformation member 212a expands more than the second heat deformation member 212b. For example, if the temperature difference between the exterior member 1 and the lens barrel 2 is ΔT1, and the linear expansion coefficient of the first thermal deformation member 212a and the second thermal deformation member 212b is α, the first thermal deformation member 212a in this case The difference in expansion / contraction amount of the second heat deformation member 212b is αL0ΔT1.

  When ΔT1 exceeds a desired temperature difference, the first contact portion 211a and the second contact portion 211b come into contact (conductive state). At this time, contact occurs on the side surface S of each contact portion (see FIG. 9). The contact area increases as ΔT1 increases.

  In the conductive state, heat conduction from the exterior member 1 occurs and the temperature of the lens barrel 2 rises. As a result, the surface temperature of the lens 3 rises, so that the effect of preventing condensation is obtained.

  In the state shown in FIG. 10C, the maximum amount of deformation of the first heat conducting unit 210a is regulated by the regulating member 240 provided on the exterior member. On the other hand, the second heat conducting unit 210b continues to be deformed and no longer comes into contact with the first heat conducting unit 210a. That is, it is a non-conductive state.

  As described above, when the temperature of the entire lens device L2 exceeds the predetermined temperature Ts and becomes high, it is possible to suppress the lens 3 from being adversely affected by the temperature rise.

  In the state shown in FIG. 10D, the temperature of the exterior member 1 is lowered earlier than the temperature of the lens barrel 2, and the first heat deformation member 212a contracts relative to the second heat deformation member 212b. If the temperature difference between the exterior member 1 and the lens barrel 2 at that time is ΔT2, the difference in shrinkage between the first thermal deformation member 212a and the second thermal deformation member 212b is αL1ΔT2.

  In this case, the heat conducting part 210b and the first heat conducting part 210a are not in contact (non-conducting state), and the heat of the lens barrel 2 is suppressed from being taken away by the exterior member 1, so that the lens 3 may be cooled too much. There is no.

(Summary)
With the above configuration, the glass temperature of the lens device L2 can be kept high in an environment in which condensation is likely to occur in the lens device L2, and fogging can be prevented.

  In this embodiment, the conduction state and the non-conduction state are switched according to the temperature difference between the outside and the inside of the lens device, not the absolute temperature. That is, if the temperature difference occurs regardless of whether the external temperature is high or low, the heat conduction means functions, so that condensation can be prevented in more environments.

(Modification)
In the present embodiment, as shown in FIG. 9, the first contact portion 211a and the second contact portion 211b in the present embodiment are arranged so as not to overlap each other when viewed from the optical axis O direction. Thereby, the heat conduction means forms a heat conduction path in a plane orthogonal to the optical axis O direction, which is a predetermined direction in which the heat conduction means is deformed. With this configuration, when the temperature difference between the inside and the outside of the lens device is very large, it is possible to suppress contact between the first contact portion 211a and the second contact portion 211b and exert a large force on each other.

  Moreover, by this structure, when attaching / detaching the exterior member 1, the 1st contact part 211a and the 2nd contact part 211b are not caught.

  The configuration is not limited to this. If it is configured not to contact a predetermined direction (in the present embodiment, the optical axis O direction) but to contact in a direction orthogonal thereto, the same effect as the configuration of the present embodiment can be obtained.

  Unlike the first embodiment, the present embodiment has a configuration in which the connection / disconnection between the thermal exterior member 1 and the lens 3 can be switched when a predetermined temperature difference occurs regardless of the absolute temperature. However, when the temperature is higher than the predetermined temperature Ts, the regulating member 240 functions according to the absolute temperature.

  The first heat conducting unit 210a and the second heat conducting unit 210b are fixed in a state where a predetermined interval δ (see FIG. 9) is shifted in the optical axis O direction. By adjusting the shift amount, the temperature difference at which thermal contact is started can be adjusted. Further, the predetermined temperature Ts can be changed by adjusting the position of the regulating member 240.

(Example 3)
Hereinafter, a lens device L2 according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a schematic diagram showing the entire lens apparatus L3 to which the second embodiment of the present invention is applied. FIG. 12 is a detailed view of part C of FIG.

  The present embodiment is different from the second embodiment in the thermal deformation portion. Hereinafter, the same number is attached | subjected to the same structure as Example 2, and description is abbreviate | omitted.

(Constitution)
The heat conducting means in this embodiment is composed of a first heat conducting unit 310a and a second heat conducting means 310b.

  As shown in FIG. 12, the first thermal deformation section includes a first tube member 320a, a first filling member 321a, and a first movable member 322a. The first tube member 320a has an opening at one end thereof, and after being filled with the first filling member 321a, the first tube member 320a is sealed by the first movable member 322a. The first movable member 322a slides according to the volume change of the first filling member 321a due to the temperature change. Due to the above mechanism, the first heat-deformed portion is deformed as a whole.

  The second heat deformation usual is composed of a second tube member 320b, a second filling member 321b, and a second movable member 322b. The deformation mechanism is the same.

  The first filling member 321a and the second filling member 321b have the same body expansion coefficient, and the volumes filled in the first tube member 320a and the second tube member 320b are the same at an arbitrary temperature.

  The 1st pipe member 320a is arrange | positioned at the internal peripheral surface of the exterior member 1 so that it may deform | transform in the direction of the optical axis O which is a predetermined direction. In the present embodiment, the first tube member 320a is lengthened, the contact area with the exterior member 1 is increased, and the amount of deformation in the direction of the optical axis O is increased. The second tube member 320b is disposed so as to be wound around (in contact with the circumferential direction) around the outer peripheral surface of the lens barrel 2 so as to generate a driving force in the same direction as the first tube member 320a. . In the present embodiment, the second tube member 320b is lengthened, the contact area with the lens barrel 2 is increased, and the amount of deformation in the direction of the optical axis O is increased.

(effect)
In the present embodiment, the deformation of the heat-deformed portion can be further increased, so that the amount of heat transfer with respect to the temperature difference can be further increased. Further, the contact area between the exterior member 1 and the lens barrel 2 can be increased, and it becomes more sensitive to temperature changes.

Example 4
A lens device L2 according to a third embodiment of the present invention will be described below with reference to FIGS. The third embodiment differs from the other embodiments in the configuration of the heat conducting means. The same components as those in the other embodiments are denoted by the same reference numerals, and description thereof is omitted.

(Constitution)
FIG. 13 is a schematic view showing the entire lens device L2 in the third embodiment of the present invention. 14 is a view in the direction of arrow D in FIG. FIG. 15 is an enlarged view of a portion E in FIG.

  The heat conducting means in this embodiment has an amplifying mechanism that amplifies the expansion and contraction of the heat deforming portion. The amplification mechanism is provided between the contact portion and the thermal deformation portion.

  As shown in FIG. 13, the amplifying mechanism includes a first amplifying member 30a and a second amplifying member 30b.

  As shown in FIG. 14, the first amplifying member 30a connects the insulator member 31a, the rotating shaft 32a, the insulator member 31a and the first connecting member 33a connected to the heat conducting part, and the insulator member 31a and the heat deforming part. The second connecting member 34a.

  The lever member 31 a rotates around a rotation shaft 32 a provided on the exterior member 1. A first connecting member 33a is attached to one end of the lever member 31a and is connected to the first contact portion 411a. A second connection member 34a is attached to the other end of the lever member 31a, and is connected to the first thermal deformation portion 412a.

  As shown in FIG. 15, the first connection member 33a is engaged with a long hole formed in the first contact portion 411a. The second connection member 34a is engaged with an elongated hole formed in the first thermal deformation portion 412a. With this configuration, the lever member 31a is rotatable.

  The operation of the first amplifying member 30a will be described with reference to FIG.

  When the first thermal deformation portion 412a expands and contracts in the direction of arrow G due to a temperature change, the second connecting member 34a is moved in the direction of arrow H. As a result, the lever member 31a and the first connecting member 33a are rotated in the θ direction about the rotation shaft 32a. The first contact portion 411a moves in the direction of arrow I through the first connection member 33a.

  Now, the distance from the rotary shaft 32a to the second connecting member 34a in the lever member 31a is R1, the distance from the rotary shaft 32a to the first connecting member 33a is R2 (R2> R1), and the first thermal deformation portion 412a is deformed. The amount is ΔL1, and the movement amount ΔL2 of the first contact portion 411a. At this time, the deformation amount ΔL1 of the first thermal deformation portion 412a is amplified by the amplification mechanism of the present embodiment so that ΔL2 = (R2 / R1) × ΔL1.

  Similarly, the second amplifying member 30b includes a lever member 31b and its rotating shaft 32b, a first connecting member 33b that connects the lever member 31b and the heat conducting portion, and a second connection that connects the lever member 31b and the heat deforming portion. It is comprised from the member 34b. The operation of the second amplifying member 30b is the same as that of the first amplifying member 30a, and a description thereof will be omitted.

(effect)
In this embodiment, the deformation of the heat deformable portion can be amplified, so that the amount of heat transfer with respect to the temperature difference can be further increased.

(Modification)
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  In the present embodiment, the lens device has been described as an example. However, the present invention can also be applied to an image pickup apparatus having a camera having an image pickup element and a lens device that connects an image of a subject to the image pickup element. In this case, it is possible to provide an imaging device in which condensation does not easily occur even when used in various temperature environments. When the present invention is used for such an image pickup apparatus, it is desirable to use the lens apparatus of this embodiment as a lens apparatus for connecting an image of a subject to the image pickup element.

1 Exterior member (exterior member)
2 Lens barrel (optical holding member)
3 Glass (optical member)
4, 210a, 310a, 411a, 412a 1st heat conduction part 5, 210b, 310b, 411b, 412b 2nd heat conduction part

Claims (13)

An optical member;
An optical holding member for holding the optical member;
An exterior member that covers the optical holding member,
Heat conduction means capable of conducting heat outside the lens device to the optical member through the exterior member;
The heat conducting means switches between a conductive state in which the external heat is conducted to the optical member and a non-conductive state in which the heat is not conducted according to one or both of the temperature outside the lens device and the temperature of the optical member. A lens device. The heat conducting means is configured by attaching members having different thermal expansion coefficients so as to be deformed according to temperature, so that the member on the optical member side is a member having a higher thermal expansion coefficient. , Connected to the exterior member or the optical holding member,
The heat conducting means contacts the member on the side to which the heat conducting means is not connected when the external temperature is higher than the temperature of the optical member, and enters the conducting state. 2. The lens device according to 1. The heat conducting means includes first and second heat conducting portions having a plate shape,
Each of the first and second heat conducting parts has a configuration in which members having different coefficients of thermal expansion are attached to each other.
Both ends of the first heat conducting portion are optically attached to the exterior member, and both ends of the second heat conducting portion are optically curved to the optical holding member in a state of being convex toward the exterior member. The side of the member is connected so as to be a member having a larger coefficient of thermal expansion,
When the external temperature is higher than the first temperature, the first heat conducting unit is deformed so as to protrude toward the optical member, and the second heat conducting unit has a temperature of the optical member. When the temperature is higher than the second temperature, it is deformed to the optical member side,
When the external temperature is higher than the first temperature and the temperature of the optical member is lower than the second temperature, the first and second heat conducting parts come into contact with each other and enter the conductive state,
3. The non-conductive state without contact when the external temperature is lower than the first temperature or when the temperature of the optical member is higher than the second temperature. 4. Lens device. The first member is attached to both ends of the second member;
When the external temperature is higher than the first temperature and the temperature of the optical member is lower than the second temperature, the second member in the first heat conducting unit and the second heat conduction The lens device according to claim 3, wherein the second member in the portion comes into contact with each other and enters the conductive state. The heat conducting means includes first and second heat conducting portions,
Each of the first and second heat conducting portions includes a contact portion and a thermally deformable portion that thermally expands and contracts in a predetermined direction.
The heat deformation part of the first heat conduction part is fixed to the exterior member, and the heat deformation part of the second heat conduction part is fixed to the optical holding member, respectively.
The contact portion is slidable in the predetermined direction and is held by the thermal deformation portion with an interval in the predetermined direction,
When the difference between the external temperature and the temperature of the optical member is larger than a predetermined temperature difference, the contact portion is moved in the predetermined direction due to the deformation of the thermal deformation portion, and is brought into contact with the conductive state. The lens device according to claim 1, wherein the lens device is configured as follows. The thermal deformation portion is
A tube member in which an opening is formed, a filling member filled in the tube member, a movable member that closes the opening and connects to the contact portion,
The lens apparatus according to claim 5, wherein the movable member moves the contact portion by thermal expansion and contraction of the filling member. The lens device according to claim 6, wherein the tube member is in contact with the inner peripheral surface of the exterior member or the outer peripheral surface of the optical holding member in the circumferential direction. The said 1st, 2nd heat conduction part has an amplification means to amplify the deformation amount of the said heat deformation part, and to move the said contact part. The lens device described. The lens device according to any one of claims 5 to 8, wherein the contact portions are in contact with each other in a direction orthogonal to the predetermined direction to be in the conductive state. The lens device according to claim 9, wherein the contact portion has a convex portion, and the convex portion is disposed so as not to overlap when viewed from the predetermined direction. 11. The lens device according to claim 5, further comprising a regulating member that regulates a deformation amount of the heat deformation portion of the first heat conducting portion. The lens apparatus according to claim 1, wherein the temperature of the exterior member is used as the external temperature, and the temperature of the optical holding member is used as the temperature of the optical member.   An imaging apparatus comprising: a camera having an imaging element; and the lens apparatus according to claim 1, wherein the lens apparatus forms an image of a subject on the imaging element of the camera.

Images