JP4343339B2 - Lens guide mechanism - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a lens guide mechanism for a movable lens frame.
[0002]
[Prior art and its problems]
For example, in a zoom finder that changes the finder field of view by moving the zoom lens (movable lens) back and forth in the optical axis direction, each component for guiding the movable lens is provided with play that allows manufacturing errors. . If this movement causes the movable lens to move in a direction perpendicular to the optical axis, unnecessary fluctuations (variations other than the magnification change) occur in the viewfinder field. Conventionally, the movable lens is moved in any direction perpendicular to the optical axis. A biasing means for biasing is provided.
[0003]
As this urging means, a device using a restoring force for opening a urging sheet formed by bending a synthetic resin sheet material, for example, a sheet material made of vinyl chloride (PVC), at a certain angle is known. . This device uses an urging sheet bent in a V shape between a movable lens and a lens frame (fixed frame), and utilizes the restoring force to open the sheet. There is an advantage that the urging force does not become weak even if the urging sheet returns to the flat plate depending on the temperature.
[0004]
However, depending on the positional relationship between the movable lens and the lens frame (fixed frame), the restoring force that closes the biasing sheet may be used . In this case, the biasing force of the biasing sheet may change over time or increase in temperature. There was a problem that gradually weakened.
[0005]
OBJECT OF THE INVENTION
Accordingly, the present invention provides a lens guide device that moves and urges a movable lens in a direction perpendicular to the optical axis by an urging force for closing a urging sheet bent in a V shape, and is affected by aging and temperature changes. An object is to provide a difficult lens guide mechanism.
[0006]
Summary of the Invention
A lens guide mechanism according to the present invention includes a movable lens having a lens portion and guide holes and guide pins located on both sides of a plane including the optical axis of the lens portion; A guide shaft that fits freely, parallel to the optical axis; a biasing sheet fixing wall surface formed on the fixed frame, having a straight groove parallel to the optical axis where the guide pin fits slidably; one surface portion is the fixed frame The abutment surface portion that is fixed along the fixed wall surface of the urging sheet and bent at a certain angle with respect to the one surface portion is opened from a free state to abut against the movable lens, and the restoring force of the corresponding surface portion A biasing sheet made of a synthetic resin material that biases the movable lens in a direction orthogonal to the optical axis; and a maximum opening angle of the contact surface portion of the biasing sheet so that the corresponding contact surface portion always contacts the movable lens. to regulate the It is characterized by having; regulating member provided on the fixed frame.
[0007]
The present invention can be applied to a movable lens of any optical apparatus. However, if the present invention is applied to a magnifying lens of a finder, it is possible to prevent the viewfinder field from changing.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of the zoom finder according to the present embodiment. This zoom finder has a straight guide shaft 20, a finder frame (fixed frame) 30, and a variable power lens (movable lens) 10. The rectilinear guide shaft 20 and the finder frame 30 have a uniform cross section extending in a direction (optical axis direction) perpendicular to the paper surface. The finder frame 30 having a light shielding property is fixed to a camera side member (not shown) and covers the entire movement range of the variable magnification lens 10 in the optical axis direction. The lens 10 and the rectilinear guide shaft 20 are accommodated.
[0009]
Guide holes 11 parallel to the optical axis are formed at the corners of the variable magnification lens 10. The guide shaft 20 passes through the guide hole 11 and holds the variable magnification lens 10 so as to freely rotate and slide. A cylindrical guide pin 12 is formed at a substantially symmetrical position of the guide hole 11 of the variable power lens 10 with the vertical plane including the optical axis as the center of symmetry. On the other hand, the finder frame 30 is formed with a rectilinear groove 32 corresponding to the guide pin 12. The rectilinear groove 32 has a width slightly larger than the diameter of the guide pin 12 and is formed long in the optical axis direction. The guide pin 12 is loosely engaged with the rectilinear groove 32 and guides the zoom lens 10 to be movable in the optical axis direction while preventing the zoom lens 10 from rotating about the guide shaft.
[0010]
A play is provided between the guide pin 12 and the straight groove 32 in consideration of assembly workability and accuracy. For this reason, the variable magnification lens 10 can be slightly rotated around the rectilinear guide shaft 20, and the visual field changes when this rotation occurs. In order to prevent this change in the field of view, it is necessary to constantly urge the zoom lens 10 in any direction orthogonal to the optical axis, and the urging sheet 40 is used for this purpose.
[0011]
In this embodiment, considering the positional relationship between the rectilinear guide shaft 20 (guide hole 11) and the rectilinear groove 32 (guide pin 12), the zoom lens 10 is rotated about the guide shaft 20 in the clockwise direction in FIG. It has been energized. The urging sheet 40 is made of a vinyl chloride (PVC) flat plate in which a contact surface portion 42 is bent at a certain angle with respect to a fixed surface portion (one surface portion) 41. The bent corner portion is positioned in accordance with the corner between the inner wall of the side surface of the finder frame 30 opposite to the rectilinear guide shaft 20 where the rectilinear groove 32 is provided and the inner wall of the upper surface, and a fixed surface portion (one surface portion) 41. Is fixed to the inner wall of the side surface of the finder frame 30 opposite to the rectilinear guide shaft 20 where the rectilinear groove 32 is provided with a double-sided tape 50, and the contact surface portion 42 is positioned in the space above the variable magnification lens 10. The biasing sheet 40 is installed in a state where it is opened more than a free state where no force is applied (the state indicated by a two-dot chain line in FIG. 1), and the variable power lens 10 is moved downward by a restoring force to be closed. Giving the pressing force to
[0012]
Since the urging sheet 40 is formed by bending a PVC flat plate so as to maintain a constant angle, the urging sheet 40 may be restored to a flat plate under aging or high temperature, and the urging force may be lost. In order to prevent this, a restriction member (protrusion) 31 that is long in the optical axis direction is provided on the inner wall of the upper surface of the finder frame 30. When the protrusion 31 abuts against the abutment surface portion 42, the urging sheet 40 is restricted from opening more than the angle indicated by the solid line in FIG. 1, and the abutment surface portion 42 is abutted against the variable magnification lens 10 at all times. ing. The size of the protrusion 31 may be appropriately determined in consideration of the backlash of the guide pin 12 and the rectilinear groove 32 and the elasticity of the urging sheet 40. That is, the urging sheet 40 can maintain the urging force that urges the variable magnification lens 10 downward without opening even if it is opened due to secular change or high temperature.
[0013]
FIG. 2 shows a case where it is not appropriate to use the restoring force to open the urging sheet 40 bent in a V shape. In other words, in this example, the guide shaft 20 and the point of application of the contact surface portion 42 of the urging sheet 40 are positioned substantially symmetrically with respect to the optical axis of the variable magnification lens 10. A biasing force in the direction of rotation cannot be applied. In FIG. 2, the same reference numerals are given to components common to FIG. 1.
[0014]
In the above embodiments, the present invention is applied to the zoom lens guide mechanism for zooming lens. However, the present invention is not limited to this, and the present invention can be applied to a guide mechanism for a diopter adjustment lens.
[0015]
【The invention's effect】
According to the present invention, in the lens guide device that moves and urges the movable lens in the direction orthogonal to the optical axis by the urging force that is intended to close the urging sheet bent in a V shape, Even if there is a change, the movable lens can always be urged in a certain direction.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a lens guide mechanism according to the present invention.
FIG. 2 is a front view corresponding to FIG. 1 showing an example of an arrangement in which use of the restoring force to open a biasing sheet bent in a V shape is inefficient.
[Explanation of symbols]
10 Variable lens (movable lens)
11 Guide hole 12 Guide pin 20 Straight guide shaft 30 Finder frame 31 Restriction member (protrusion)
32 Straight groove 40 Energizing sheet 41 Fixed surface portion 42 Contact surface portion 50 Double-sided tape

Claims (2)

A movable lens having a lens part and guide holes and guide pins located on both sides of the lens part, the plane including the optical axis;
A guide shaft parallel to the optical axis, fitted in the guide hole so as to be relatively rotatable and relatively slidable;
An urging sheet fixing wall surface formed on a fixed frame, having a rectilinear groove parallel to an optical axis into which the guide pin fits slidably;
One surface portion is fixed along the fixed wall of the urging sheet of the fixed frame, and the contact surface portion bent at a certain angle with respect to the one surface portion is opened from a free state to contact the movable lens. A biasing sheet made of a synthetic resin material that biases the movable lens in a direction orthogonal to the optical axis by the restoring force of the contact surface; and the maximum opening angle of the contact surface of the biasing sheet, the corresponding contact surface is always movable A regulating member provided on the fixed frame for regulating the lens so as to contact the lens;
A lens guide mechanism. The lens guide mechanism according to claim 1, wherein the movable lens is a zoom lens of a zoom finder.

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