JP4144145B2 - EVF diopter adjustment mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an EVF diopter adjustment mechanism effective for use in an electric view finder (hereinafter referred to as EVF) used for a video camera or the like.
[0002]
[Prior art]
In recent years, there has been a great demand for miniaturization of video cameras, and in particular, there is a high demand for miniaturization of EVF units that are difficult to miniaturize in order to secure a predetermined optical path. Among these, downsizing and operability of a diopter adjustment mechanism that performs focusing in accordance with the user's visual acuity are also important issues. A conventional EVF diopter adjustment mechanism will be described below.
[0003]
FIG. 8 is an exploded perspective view of a conventional EVF diopter adjustment mechanism. 9 to 10 are exploded perspective views of an EVF unit including a conventional EVF diopter adjustment mechanism. FIG. 11 is a partial bottom view of the vicinity of the lens support member as viewed from below. FIG. 12 is a partial cross-sectional view of the diopter guidance unit.
[0004]
In the figure, a diopter adjustment case 1 which is a diopter holding member is formed with an opening 1a into which a tip 2a of a diopter adjustment knob 2 is inserted, and a guide groove which is a diopter guide is formed on the inner surface. 1b is formed. One end of the diopter adjustment knob 2 is formed with a cam follower portion 2b that fits with a cam groove 6c that is a cam portion for diopter adjustment formed on the lower surface of the lens holder 6 that is a lens support member to which the lens 7 is fixed. is doing. The resin holding plate 4 for attaching the diopter adjustment knob 2 to the diopter adjustment case 1 is formed with a follower opening 4b into which the cam follower portion 2b of the diopter adjustment knob 2 is inserted. The diopter adjustment knob 2 is sandwiched between the diopter adjustment case 1 and the holding plate 4, and the diopter adjustment case 1 and the holding plate 4 are fixed with screws 5 so that the diopter adjustment knob 2 is only in the range of the follower opening 4 b. It is held movable.
[0005]
On the side surface of the lens holder 6, a guide rib 6b that is a diopter guide is formed. The lens holder 6 is inserted in the diopter adjustment case 1. As shown in FIG. 12, the cross-sectional shape of the guide rib 6b and the guide groove 1b of the diopter adjustment case 1 is a trapezoid having two slopes with an angle β as shown in FIG. The eye cap 8 is fitted and attached to the diopter adjustment case 1. In this way, the EVF diopter adjustment mechanism 11 is configured. The image display unit 12 is sandwiched and accommodated between the upper EVF case 13 and the lower EVF case 14. The EVF case upper 13 and the EVF case lower 14 are fixed by a case fixing screw 10. The EVF diopter adjustment mechanism 11 is inserted into a fixed case, and a detachable spring portion 1e formed in the diopter adjustment case 1 and a fitting portion (not shown) formed inside the fixed case are fitted. And detachably fixed. Finally, the EVF diopter adjustment mechanism 11 and the EVF case lower part 14 are securely fixed by the adjustment mechanism fixing screw 15, and the assembly of the EVF unit is completed.
[0006]
The operation of the conventional EVF diopter adjustment mechanism configured as described above will be described with reference to FIGS.
[0007]
When the diopter adjustment knob 2 is moved, the cam follower portion 2b pushes the cam groove of the lens holder 6 to move the lens holder 6 along the diopter guide portion, so that the lens 7 is positioned in accordance with the user's visual acuity. The diopter is adjusted so that
[0008]
At this time, it is necessary to give an appropriate knob operating force and hold it at a position adjusted by the user.
[0009]
The cross-sectional shapes of the guide rib 6b and the guide groove 1b of the diopter adjustment case 1 are trapezoidal as shown in FIG. 12, and are in contact with each inclined surface. For this reason, as shown in FIG. 11, the vertical drag N = (F / sin β) at the contact slope with respect to the operating force F. If the angle β is small, the vertical drag N increases even if a slight F is applied. . Since the friction load f is generated at f = μ * N when the friction coefficient is μ, such a “wedge effect” can provide a sufficient friction load f in the diopter guide portion. The friction load f can be held at a position adjusted by the user, and an appropriate knob operating force F can be applied.
[0010]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, when the friction coefficient μ at the contact surface of the guide rib 6b or the guide groove 1b that is the diopter guide portion is slightly increased during the knob operation due to an environmental change or the like, the guide rib 6b on one side The frictional load f increases and stops moving, and when the diopter adjustment knob 2 is further moved, the lens holder 6 tilts. Therefore, the guide ribs 6b and the guide grooves 1b on both sides are further pressed against the inclined surface, and the frictional force f increases more rapidly, the operation force F becomes unstable, and the more the diopter adjustment knob 2 is pushed, the more it moves. There was a problem of disappearing.
[0011]
As a method for solving this problem, the length B of the diopter guide unit with respect to the distance A between the left and right diopter guide units shown in FIG. 11 may be sufficiently long. It was.
[0012]
The present invention solves the above-described problems, and an object thereof is to provide a small EVF diopter adjustment mechanism while maintaining a stable operation force.
[0013]
[Means for Solving the Problems]
In order to achieve this object, the EVF diopter adjustment mechanism of the present invention includes a lens support member that fixes a lens and forms a cam portion for diopter adjustment, and a cam follower portion that fits the cam portion. A diopter adjustment knob, and a diopter holding member that holds the lens support member and the diopter adjustment knob, and a part of the diopter holding member and a part of the lens support member are fitted to each other. An EVF diopter adjustment mechanism that adjusts the diopter according to the visual acuity of the user by moving the lens in the optical axis direction along the diopter guide formed by combining the diopter and the diopter adjustment knob. And a torque generating member that is fitted with the groove and has a convex portion that applies a predetermined load.
[0014]
An object of the present invention is to provide a small EVF diopter adjustment mechanism while maintaining a stable operating force.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect of the present invention, there is provided a lens support member for fixing a lens and forming a cam portion for diopter adjustment, and a diopter adjustment knob for forming a cam follower portion to be fitted to the cam portion. A diopter holding member that holds the lens support member and a diopter adjustment knob, and a part of the diopter holding member and a part of the lens support member are fitted to each other. An EVF diopter adjustment mechanism that adjusts the diopter according to the visual acuity of the user by moving the lens in the optical axis direction along the diopter guide, and is fitted into a groove formed on the diopter adjustment knob. And, it has a configuration characterized by comprising a torque generating member formed with a convex portion that gives a predetermined load, and by this configuration, the necessary load can be given only to the diopter adjustment knob, Diopter guidance There is no need to generate a Oite friction force. For this reason, it is not necessary to increase the length B of the diopter guide portion with respect to the distance A between the diopter guide portions at the two left and right locations, so that a small EVF diopter adjustment mechanism can be provided while maintaining a stable operating force. Has an effect.
[0016]
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0017]
(Embodiment 1)
1 to 2 are exploded perspective views of the EVF diopter adjustment mechanism according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view of the EVF unit including the EVF diopter adjustment mechanism according to the first embodiment of the present invention. 4 to 5 are side sectional views of the EVF diopter adjustment mechanism according to the first embodiment of the present invention. FIG. 6 is a partial bottom view of the EVF diopter adjustment mechanism according to the first embodiment of the present invention. FIG. 7 is a partial cross-sectional view of the diopter guide portion of the EVF diopter adjustment mechanism according to the first embodiment of the present invention.
[0018]
In the figure, a diopter adjustment case 101 which is a diopter holding member is formed with an opening 101a into which the tip 102a of the diopter adjustment knob 102 is inserted, and a guide groove which is a diopter guide is formed on the inner side surface. 101b is formed. A lens fitting claw 106a is formed on the lens holder 106 which is a lens support member for fixing the lens 107. A fitting rib 107a is formed in the lens 107, and this is fitted and fixed to the lens fitting claw 106a. At one end of the diopter adjustment knob 102, a cam follower portion 102b that fits with a cam groove 106c that is a cam portion for diopter adjustment formed on the lower surface of the lens holder 106 is formed.
[0019]
The holding plate 104 that attaches the diopter adjustment knob 102 to the diopter adjustment case 101 uses a thin stainless steel plate for springs, and a follower opening 104b into which the cam follower portion 102b of the diopter adjustment knob 102 is inserted is formed. . The torque piece 103, which is a torque generating member, is formed with a convex portion 103c that applies a predetermined load.
[0020]
On the other hand, the diopter adjustment knob 102 is formed with a groove portion 102c that fits into the convex portion 103c. At both ends of the torque piece 103, fitting projections 103a that fit into piece fitting holes 104c formed in the pressing plate 104 are formed. The torque piece 103 is held by the holding plate 104 in advance by fitting the fitting projection 103a into the piece fitting hole 104c. The diopter adjustment knob 102 and the torque piece 103 are sandwiched between the diopter adjustment case 101 and the holding plate 104. By fixing the diopter adjustment case 101 and the holding plate 104 with screws 105, the diopter adjustment knob 102 is moved to the follower opening 104b. It is held to be movable only within the range of.
[0021]
The holding plate 104 is formed with a spring portion 104 a that abuts against a spring contact portion 103 b formed on the torque piece 103 and applies a load that presses the torque piece 103 against the diopter adjustment knob 102. The cross-sectional shapes of the fitting convex portion 103a and the groove portion 102c are trapezoidal as shown in FIGS. 4 and 5, and are in contact with each other while being urged by the spring portion 104a on the slope. On the side surface of the lens holder 106, a guide rib 106b, which is a diopter guide part, is formed.
[0022]
The lens holder 106 is inserted into the diopter adjustment case 101. The cross-sectional shape of the guide rib 106b and the guide groove 101b of the diopter adjustment case 101 is a rectangle as shown in FIG. An eye cap 108 made of silicon rubber is fixed to an eye cap fitting 109 made of a spring stainless plate by insert molding. The eye cap fitting 109 is formed with a fitting bent portion 109a.
[0023]
The eye cap 108 is fitted with the fitting bent portion 109 a in the fitting hole 101 d formed in the diopter adjustment case 101 and fixed with the eye cap screw 110. In this way, the EVF diopter adjustment mechanism 111 is configured. First, the image display unit 112 is temporarily fixed by being engaged with a temporary fixing claw 114 b formed on the EVF case lower part 114, and then the EVF case upper part 113 is covered and stored. The EVF case lower part 114 and the EVF case upper part 113 are temporarily fixed by fitting the case fitting hole part 113a and the case fitting claw part 114a. An upper fitting rib 113c and a lower fitting rib 114c are formed on the upper EVF case 113 and the lower EVF case 114, respectively.
[0024]
On the other hand, the diopter adjustment case 101 is formed with a case fitting groove 101c. When the EVF diopter adjustment mechanism 111 is inserted into the fixed case, the upper fitting rib 113c and the lower fitting rib 114c are fitted into the case fitting groove 101c. Even in this portion, the upper EVF case 113 and the lower EVF case are fitted. 114 is fixed. When the EVF diopter adjustment mechanism 111 is inserted to the back, the attachment / detachment spring portion 101g formed in the diopter adjustment case 101 and the through hole 113b formed inside the fixed EVF case 113 are fitted together, and the EVF unit is assembled. Is completed.
[0025]
The operation of the EVF diopter adjustment mechanism of the present embodiment configured as described above will be described with reference to FIGS.
[0026]
When the diopter adjustment knob 102 is moved, the cam follower portion 102b pushes the cam groove 106c of the lens holder 106, whereby the lens holder 106 moves along the diopter guide portion, and the lens 107 is adjusted to the user's visual acuity. The diopter is adjusted to be in position.
[0027]
Since a large frictional load is generated by the “wedge effect” due to contact with the slope of the convex portion 103c of the torque piece 103 and the groove portion 102c of the diopter adjustment knob 102 while being urged by the spring portion 104a, the torque piece 103 is weak. A predetermined load necessary for the diopter adjustment knob 102 can be applied even with the spring pressure.
[0028]
With this load, an appropriate knob operating force can be applied and held at a position adjusted by the user.
[0029]
On the other hand, the cross-sectional shape of the guide rib 106b and the guide groove 101b of the diopter adjustment case 101 is rectangular as shown in FIG. 7, and is in contact with the end face, so the friction load f is f = μ * F. There is no rust effect as in the prior art described above. For this reason, even if the friction coefficient μ slightly changes due to environmental changes or the like, the friction load f does not become abnormally large.
[0030]
Further, by using a thin stainless steel plate for springs as the press plate 104 that has conventionally been made of a thick resin, an increase in the height of the EVF diopter adjustment mechanism due to the addition of the torque piece 103 can be suppressed.
[0031]
As described above, in the present embodiment, the torque piece 103 formed with the convex portion 103c that fits the groove portion 102c formed in the diopter adjustment knob 102 and applies a predetermined load is provided, so that the necessary load can be viewed. Since it can be given only to the degree adjustment knob 102, it is not necessary to generate a frictional force in the diopter guidance part. For this reason, it is not necessary to increase the length B of the diopter guide unit with respect to the distance A between the diopter guide units at the two left and right locations, and thus a small EVF diopter adjustment mechanism is configured while maintaining a stable operating force. Can do.
[0032]
In the present embodiment, a thin spring stainless plate is used as the pressing plate 104, but the material is not necessarily a spring stainless plate.
[0033]
The eye cap 108 is configured by fixing an eye cap metal fitting 109 made of a stainless steel plate for springs to silicon rubber by insert molding. However, such a configuration is not necessarily required.
[0034]
【The invention's effect】
As described above, the present invention includes a torque generating member that is fitted in a groove formed on the diopter adjustment knob and has a convex portion that applies a predetermined load, so that the necessary load is applied only to the diopter adjustment knob. Therefore, it is not necessary to generate a frictional force in the diopter guidance unit. For this reason, it is not necessary to increase the length B of the diopter guide unit with respect to the distance A between the diopter guide units at the two left and right locations, and thus a small EVF diopter adjustment mechanism is configured while maintaining a stable operating force. Can do.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an EVF diopter adjustment mechanism according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view of an EVF diopter adjustment mechanism according to Embodiment 1 of the present invention. FIG. 4 is an exploded perspective view of the EVF unit including the EVF diopter adjustment mechanism according to the first embodiment of the present invention. FIG. 4 is a side sectional view (far vision side) of the EVF diopter adjustment mechanism according to the first embodiment of the present invention.
FIG. 5 is a side sectional view (myopia side) of the EVF diopter adjustment mechanism according to the first embodiment of the present invention.
6 is a partial bottom view of the EVF diopter adjustment mechanism according to the first embodiment of the present invention. FIG. 7 is a partial cross-sectional view of the diopter guide portion of the EVF diopter adjustment mechanism according to the first embodiment of the present invention. 8 is an exploded perspective view of a conventional EVF diopter adjustment mechanism. FIG. 9 is an exploded perspective view of an EVF unit including a conventional EVF diopter adjustment mechanism. FIG. 10 is an exploded perspective view of an EVF unit including a conventional EVF diopter adjustment mechanism. FIG. 11 is a partial bottom view of a conventional EVF diopter adjustment mechanism. FIG. 12 is a partial cross-sectional view of a diopter guide portion of a conventional EVF diopter adjustment mechanism.
101 Diopter Adjustment Case 102 Diopter Adjustment Knob 103 Torque Piece 104 Holding Plate 105 Screw 106 Lens Holder 107 Lens 108 Eye Cap 109 Eye Cap Bracket 110 Eye Cap Screw 111 Diopter Adjustment Mechanism 112 Image Display Unit 113 Upper EVF Case 114 EVF Case under

Claims (1)

An image display unit, a lens for enlarging an image of the image display unit, a lens support member that fixes the lens and forms a cam portion for diopter adjustment, and a cam follower portion that fits the cam portion are formed A diopter adjustment knob and a diopter part holding member for holding the lens support member and the diopter adjustment knob, and a part of the diopter part holding member and a part of the lens support member are fitted to each other. An EVF diopter adjustment mechanism that adjusts the diopter according to the visual acuity of the user by moving the lens in the optical axis direction along the diopter guide formed by combining the diopter and the diopter adjustment knob. An EVF diopter adjustment mechanism comprising a torque generating member that is fitted in the groove and has a convex portion that applies a predetermined load.

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