JPH073373Y2 - Focus adjustment mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a focus adjusting mechanism at the time of assembling a photographing lens used in a camera, particularly a compact camera.

[Conventional technology]

When assembling a compact camera or the like, it is necessary to adjust the focus of the photographic lens in order to correct variations due to individual differences between individual cameras, but as a conventional focus adjusting mechanism, for example, a focus adjusting member whose rotation is guided is used. Connect the lens to the lens frame, set the focal length display position of the shooting lens to infinity, and rotate the focus adjustment member by the required amount to move the lens frame to adjust the focus. There are those that stop the rotation of the lens, and those that position the lens holding member and fix the lens frame to this lens holding member and move the holding member back and forth in the feeding direction to adjust the focus. It was

[Problems to be solved by the device]

However, in such a focus adjustment mechanism, when the focus is adjusted, the lens is extended, but on the other hand, in a normal camera, in order to suppress rattling in the thrust direction of the lens barrel (thrust rattling), Since the spring is stretched in the direction that suppresses the lens extension, the spring load of the lens barrel increases according to the amount of extension of the lens barrel when adjusting the focus, and the drive source for autofocus during shooting. However, there is a drawback in that the load on the vehicle increases.
Moreover, since the focus adjustment amount differs between individual cameras, the magnitude of the load also varies, which may lead to nonuniformity of the focus adjustment function of the camera and deterioration of accuracy. or,
It is said that the conventional focus adjustment mechanism has a complicated structure because of large eccentricity of the lens barrel and poor position accuracy during focus adjustment and focus adjustment during shooting due to problems in processing accuracy, and further, the number of parts is large. There was also a problem.

The present invention has been made in view of the above problems, and an object thereof is to provide a focus adjustment mechanism that does not change the load on the drive source even when focus adjustment is performed during assembly and that has a small number of parts and has a simple structure.

Another object of the present invention is to provide a focus adjusting mechanism which improves the positional accuracy by reducing the eccentricity of the lens when adjusting the focus.

[Means for Solving the Problems]

In the focus adjusting mechanism according to the present invention, a lens barrel is slidably inserted into a lens barrel mounting member pressed by an elastic member, and a pair of parallel helical cam surfaces are formed on the lens barrel mounting member. , The lens barrel is formed with protrusions that come into contact with the helical cam surfaces, and at least one of the protrusions has elasticity, so that the lens barrel can be slid and rotated during assembly to adjust the focus. It is the one.

Further, the lens frame mounting member is provided with a hole for positioning the mounting member with respect to the main plate and an engaging groove for preventing rotation with respect to the adjusting base plate.

[Action]

Therefore, when assembling the focus adjustment mechanism, the lens barrel mounting member can be held at a predetermined position and the lens barrel can be slidably rotated to adjust its position. The lens barrel can be locked with the lens barrel mounting member.

Further, since the lens barrel frame mounting member that supports the lens barrel can be positioned by the hole and the engaging groove, the eccentricity of the lens at the time of focus adjustment or the like can be suppressed to be small.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

In the drawings, FIG. 1 is a cross-sectional view of a main part of the focus adjusting mechanism.
Is a base plate fixed to the camera body, 2 is an annular feeding member that is rotatably supported by the base plate 1 and is connected to a drive source (not shown) through a reduction mechanism, and 2a is an equal distance to the feeding member 2 such as 3 The feeding pin 3, which is permanently installed, is supported on the feeding member 2, and is a substantially cylindrical lens barrel mounting member that can slide in the direction of the optical axis 1 according to the rotation of the member 2. Reference numeral 4 denotes a lens. A lens barrel that is slidably inserted into the lens barrel mounting member 3 and holds a lens group (not shown). It is designed to slide together. Then, in the lens barrel mounting member 3, 3a
Is a feeding cam surface which is formed as an inclined surface on the outer side of the lower end and which comes into contact with the feeding pin 2a (see FIG. 2), and three surfaces are provided facing the feeding pin 2a at equal intervals (third surface). See figure). Reference numeral 3b denotes a first helical cam surface formed at a predetermined angle with respect to the circumferential direction in the concave portion on the inner side surface of the lens barrel mounting member 3, and three surfaces are provided at equal intervals as shown in FIG. ing. Reference numeral 3c designates a second helical cam surface which is also provided in the concave portion on the inner side surface in a position parallel to and opposite to the first helical cam surface 3b, and reference numerals 5 and 6 respectively denote a pair of outer surface of the mounting member 3 which face each other. An arm, 5a, is a hole formed in the arm 5 for inserting the shaft 1a of the base plate 1 to position the lens barrel mounting member 3 with respect to the base plate 1, and 6a is formed in the arm 6 for the base plate 1. A U-shaped groove or an engaging groove for engaging the shaft 1b to prevent the lens barrel mounting member 3 from rotating with respect to the main plate 1.
The lens can be positioned to suppress eccentricity of the lens during focus adjustment and focus adjustment. Reference numeral 7 denotes a spring mounted between the camera body and the upper end (see FIG. 1) of the lens barrel mounting member 3 so that the mounting member 3 can be elastically pressed toward the main plate 1 to prevent thrust rattling. Has become. Further, in the lens barrel frame 4, 8 is a first lens barrel whose upper end is provided with a claw 8a, and 9 is fitted into the first lens barrel 8 by engaging the claw 8a with the long hole 9a. The second lens barrel, which is the first and second lens barrel 8,
The lens 9 can be zoomed by relatively rotating it within the width of the slot 9, but it is usually tightly fitted as the lens barrel 4 so as to rotate integrally. 10 is the first lens barrel 8
The first protruding portion 10a protruding from the central portion of the outer surface of the first protruding portion 10a is formed on the lower surface of the first protruding portion 10.
When the lens barrel 4 is slidably rotated, the first protrusion 10 is guided by the first helical cam surface 3b to move the lens barrel 4 forward and backward with respect to the lens barrel mounting member 3. Excuse me. Reference numeral 11 denotes an arm-shaped second protrusion protruding from the lower end of the second lens frame 9 and extending in the circumferential direction of the lens frame 9 at a radius slightly larger than the radius of the lens frame 9, and 11a denotes a second protrusion. An inclined surface formed on the upper surface of the tip of the portion 11 and in contact with the second helical cam surface 3c, the inclined surface of the first protruding portion 10.
While guiding the sliding rotation of the lens barrel 4 together with 10a, the lens barrel 4 is pressed against the lens barrel mounting member 3 due to the elasticity of the arm of the second projecting portion 11 so that the lens mirror can be moved at any position. The frame 4 can be held and positioned. Three pairs of the first and second protrusions 10 and 11 are provided at equal intervals at positions corresponding to the first and second helical cam surfaces 3b and 3c, respectively. Further, since the lens barrel 4 is held in close contact with the inner lower end surface 3d of the lens barrel mounting member 3, decentering of the lens is less likely to occur during sliding rotation.

The present embodiment has the above configuration, and the operation will be described below. When adjusting the focus at the time of assembling the camera, the lens barrel mounting member 3 is aligned with, for example, the display unit showing the infinite focal length of the taking lens, and at this time, the lens barrel 4 is not at the infinite focal length position. Sometimes, when the lens barrel 4 is slidably rotated with respect to the lens barrel mounting member 3, the first and second protrusions 10 and 11 resist the elasticity of the second protrusion 1 and the first and second helical cam surfaces are moved. While being guided by 3b and 3c, the lens barrel 4 can be moved back and forth to a position with an infinite focal length, and if stopped at that position, the second protrusion 11
The elasticity of the lens barrel 4 causes the lens barrel 4 to attach to the lens barrel mounting member 3
The focus adjustment is completed. Further, since the thrust rattling suppressing spring 7 is mounted on the lens barrel frame mounting member 3, the load applied to the drive source does not fluctuate due to focus adjustment. When an autofocus mechanism (not shown) measures the distance at the time of photographing and drives the driving source by a required amount, the feeding member 2 is rotated and the feeding pin 2a and the cam surface 3a work to move the lens barrel mounting member 3 and the lens. The lens frame 4 is guided by the shafts 1a and 1b of the main plate 1 and is integrally extended by a required amount to adjust the focus.

In addition, the hole 5a of the arm 5 of the lens barrel mounting member 3 is set to the shaft of the main plate 1.
The lens barrel mounting member 3 can be positioned by fitting it to 1a, and the U-shaped groove 6a of the arm 6 is engaged with the shaft 1b to prevent the mounting member 3 from rotating, thereby aligning the optical axis of the lens barrel 4. Can be performed with high accuracy, and the outer surface of the lens barrel 4 can be attached to the inner lower end surface 3d
Therefore, the eccentricity of the lens is small during focus adjustment and focus adjustment during shooting.

As described above, according to the present embodiment, it is possible to provide a camera having a uniform and highly accurate focus adjustment function without changing the load applied to the drive source due to focus adjustment during assembly.

In addition, it is possible to reduce the eccentricity of the lens when adjusting the focus and improve the positional accuracy of the lens barrel.

Needless to say, the first protrusion may have a structure having elasticity like the second protrusion.

Further, by making the inner diameter of the hole 5a of the arm 5 slightly larger than the outer diameter of the shaft 1a, the lens barrel mounting member 3 can be slightly slidably adjusted between the hole 5a and the U-shaped groove 6a. You may

[Effect of device]

As described above, according to the focus adjusting mechanism of the present invention, the elastic member for suppressing the thrust play is attached to the lens barrel mounting member, and the lens barrel is slidably held by the lens barrel mounting member. Therefore, the load applied to the drive source does not change even by focus adjustment during assembly, and a uniform and highly accurate focus adjusting function can be maintained, and the number of parts can be reduced and the structure can be simplified.

In addition, it is possible to reduce the eccentricity of the lens when adjusting the focus and improve the positional accuracy of the lens barrel.

[Brief description of drawings]

1 to 4 show a focus adjusting mechanism according to the present invention. FIG. 1 is a sectional view of a main part, FIG. 2 is a partial side view of a lens barrel mounting member, and FIG. 3 is a lens. FIG. 4 is a plan view of the lens frame mounting member, and FIG. 4 is a side view of the lens frame. 3 ... Lens lens frame mounting member, 3b ... First helical cam surface, 3c ... Second helical cam surface, 4 ... Lens lens frame, 5,
6 ... arm, 5a ... hole, 6a ... U-shaped groove, 10 ... first protrusion, 11 ... second protrusion.

Claims (2)

[Scope of utility model registration request] 1. A lens barrel frame is slidably fitted into a lens barrel frame mounting member pressed by an elastic member, and a pair of parallel helical cam surfaces are formed on the lens barrel frame mounting member. Protrusions are formed on the lens barrel to contact the pair of helical cam surfaces respectively, and at least one of the protrusions is given elasticity, and the lens barrel is attached to the lens barrel mounting member during assembly. A focus adjustment mechanism that allows you to adjust the focus by rotating the slide. 2. The lens barrel frame mounting member is provided with a hole for positioning the lens barrel frame mounting member with respect to a main plate and an engagement groove for preventing rotation with respect to the main plate. The focus adjusting mechanism according to claim (1) of the new model registration claim.