JP3038595B2 - Focus lens control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus lens control device, and more particularly, to a focus lens control device capable of electrically adjusting an infinite position of a focus lens and eliminating the need for a mechanical member. It concerns the device.

[Conventional technology]

In a conventional autofocus camera, in order to obtain shooting distance information, a method of calculating shooting distance information based on an extension amount from an infinite position of a focus lens to a focusing position has been adopted.

In such an autofocus camera, in particular, a compact camera (lens shutter camera), the focus lens is initially at an infinite position, and is controlled so as to be extended in accordance with a distance measured by a release, so that a shutter is opened and exposure is performed. Have been.

When the infinity position of the focus lens of such an autofocus camera is mechanically (mechanically) adjusted, the mechanical stopper of the focus lens and the infinity position coincide with each other. In calculating the distance, the infinite position can be used as a reference.

By the way, in a variable power lens system such as a zoom lens or a varifocal lens, in order to adjust a variation of an infinite position due to a mechanical processing error of a lens, a lens holding member, etc. It is necessary to adjust the position of the lens system.

Conventionally, infinity adjustment of a zoom lens is performed at two positions, that is, a wide side and a tele side, and it is common to perform infinity adjustment at a wide position and then perform infinity adjustment at a tele position.

However, in the case of a high-magnification zoom lens, some lens systems require further adjustment even in the middle zoom range in order to remove the swelling of the shift.

Next, a general adjustment process will be described. First, leave it in the wide state and combine multiple washers so that the image of ∞ made by a collimator etc. is focused.
Adjustment is performed by changing the entire optical system in the optical axis direction.

Next, in the telephoto state, move the focusing lens in the direction of the optical axis, adjust so that the image is focused in the same manner as in the case of wide-angle. Adjust the position of the ring and focusing lens.

In addition to the above-described adjustment mechanism, various types have been proposed. For example, Japanese Utility Model Publication No. 58-42964 (hereinafter referred to as "
The publication discloses a “fine adjustment mechanism for positioning the lens”.

In the case of the fine adjustment mechanism for lens positioning described in the first publication, a fixed lens is supported by a fixed frame, the fixed frame is fixed to the camera body, and the lens holding frame is fitted to the fixed frame so as to be able to move forward and backward. At the same time, the movable lens is supported on the lens holding frame, a cam groove for moving the lens holding frame is formed on the outer peripheral surface of the fixed frame, and the eccentric pin is rotatably supported on the peripheral wall of the lens holding frame, When adjusting the position of the movable lens,
The lens holding frame is moved in the optical axis direction, and when the lens holding frame is rotated, the eccentric shaft moves in the moving cam groove, and the outer circumferential surface of the lens holding frame has a circumferential direction orthogonal to the optical axis. Are formed, and the movement position of the eccentric pin is regulated by this recess.

In addition, a long hole is bored in this recess, and the movement position of the eccentric shaft of the eccentric pin is regulated by the long hole in the optical axis direction, and the eccentric pin is fixed by a fixing member at the adjustment position. I am trying to do it.

Also, Japanese Patent Publication No. Sho 60-42924 (hereinafter referred to as “the second gazette”)
) Disclose an "adjustable lens barrel".

In the case of the second publication, a first lens barrel having an optical element is fixedly arranged, an optical element is held at one end of the second lens barrel, and a first lens barrel is provided at the other end. Insert the end of the lens barrel,
An adjustment member for adjusting the second lens barrel in the rotation direction is provided at a position close to the play insertion portion, and each adjustment member for adjusting the inclination in the up-down direction and the horizontal direction is separated from the play insertion portion. , Respectively, so that the rotation direction of the optical element held by the second lens barrel and the positions in the vertical and horizontal directions are independently adjusted.

Further, Japanese Patent Publication No. 55-49721 (hereinafter referred to as "third publication") discloses a "lens barrel".

In the case of the third publication, the lens frame screwed into the helicoid cylinder is made to be able to expand and contract along the helicoid screw by operating the focus ring, and the movement of the helicoid cylinder is restricted directly or indirectly. A stopper for determining the position of the optical system at infinity is provided in the lens barrel, and an operating member for maintaining and canceling the stop action of the stopper is attached outside the lens barrel, and the stopper is released by this operating member. At times, by operating the focus ring, the lens frame can be retracted from the position at infinity to the rear end of the lens barrel along the helicoid screw.

[Problems to be Solved by the Invention] However, the one that adjusts the position of the focusing lens by the combination of the washer and the immobilizer,
According to the first to third publications, the lens position is adjusted by using a mechanical mechanism to adjust the infinity position.

For this reason, mechanical adjustment is required on the assembly line,
As a result, the number of assembling steps is inevitably increased, and an expensive adjusting member is also required, which has been a hindrance to cost reduction.

On the other hand, instead of mechanically adjusting and setting the infinity position, a method of electrically storing the infinity position is also conceivable. In this case, however, the mechanical stopper of the focus lens and the electrically stored infinity position are different from each other. I will not do it.

Therefore, focusing control and subject distance information cannot be obtained only from information on the lens extension amount from the infinity position to the focusing position measured by the external ranging device.

The present invention has been made in view of the above circumstances, and has as its object the infinite position adjustment can be performed electrically easily without the need for expensive adjustment members, thereby reducing manufacturing cost and cost. It is an object of the present invention to provide a focus lens control device that can reduce the adjustment cost, make the camera compact, and can perform the extension control from the infinity position to the in-focus position quickly and with high accuracy.

[Means for solving the problem]

According to a first aspect of the present invention, there is provided a storage means for electrically storing an infinite position of a focus lens that changes according to a zoom lens position as a focus lens extension from a reference position, and detecting the zoom lens position. Zoom lens system position detecting means, a distance measuring device for measuring a subject distance, and a feeding amount calculating means for calculating a feeding amount from an infinity position to an in-focus position of the focus lens based on a distance result by the distance measuring device. Adding the extension amount obtained by the extension amount calculation unit to the extension amount corresponding to the zoom lens position detected by the zoom lens system position detection unit among the extension amounts of the focus lens stored in the storage unit. The value obtained as the focus control amount from the reference position to the focus position of the focus lens The zoom lens system position detecting means of the focus lens moving amount stored in the storage means from the reference position when the camera is powered on. The focus lens is extended to the infinity position corresponding to the zoom lens position, and thereafter, the extension operation from the infinity position to the in-focus position is performed until the camera power is turned off. It is characterized in that it is configured to incorporate a lens.

According to a second aspect of the present invention, in order to achieve the above object, the infinity position of the single focal length lens or the infinity position of the focus lens of the zoom lens in which the infinity position of the focus lens is constant is determined from a reference position. Storage means for electrically storing a focus lens extension amount, a distance measuring device for measuring a subject distance, and an extension amount of the focus lens from an infinity position to an in-focus position based on a distance measurement result of the distance measurement device. A calculated moving-out amount calculating means, and a value obtained by adding a moving-out amount calculated by the moving-out amount calculating means to a moving-out amount of the focus lens stored in the storage means, from the reference position to a focusing position of the focus lens. And a feeding control means for controlling the feeding of the focus lens as the feeding control amount up to the above. The focus lens is extended to the infinity position of the focusing lens stored in the storage means, and thereafter, the extension operation from the infinity position to the in-focus position is performed until the camera is turned off, and the camera is turned off. Wherein the focus lens is extended to the reference position.

(Operation)

When the infinity position of the focus lens changes according to the zoom lens position, the focus lens control device configured as described above corresponds to the set focal length from the reference position where there is no individual difference of the camera to the infinity position. The amount of extension of the focus lens is stored in the storage means.

The extension amount calculating means calculates the extension amount from the infinity position of the focus lens to the in-focus position based on the distance measurement information detected by the distance measuring device.

When the camera is turned on, the feeding control means feeds the focus lens from the reference position to the infinity position corresponding to the zoom lens position detected by the zoom lens system position detecting means among the focus lens feeding amounts stored in the storage means from the reference position. Until the power of the camera is turned off, the value of the extension amount calculated by the extension amount calculation means is used as the extension control amount from the reference position of the focus lens to the in-focus position to perform the extension control of the focus lens.

In the case of a single focus lens or when the infinity position of the focus lens is constant, the storage means electrically stores the distance from the reference position to the infinity position of the focus lens as a focus lens extension amount.

Further, the extension amount calculating means for receiving the distance measurement value measured by the distance measuring device calculates the extension amount from the infinity position of the focus lens to the in-focus position based on the distance measurement value.

The feeding control means performs feeding control with the focus lens feeding amount from the reference position to the infinity position stored in the storage means when the camera power is turned on, and thereafter, the feeding calculated by the feeding amount calculation means until the camera power is turned off. The amount of the focus lens is controlled to be extended from the reference position to the in-focus position of the focus lens.

Then, control is performed so that the focus lens is retracted (retracted) to the reference position when the camera power is turned off.

Examples Hereinafter, examples of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a block diagram showing an overall configuration of a focus lens control device according to the present invention.

In FIG. 1, reference numeral 1 denotes control means for controlling the entire focus lens control device, and is hereinafter referred to as a CPU.

The operation switch 2 is connected to the CPU 1. The operation switches 2 include a zooming switch and a release switch which are operated during zooming operation of the zoom lens 3 from wide to tele or from tele to wide side, a distance measuring switch which is operated during distance measuring, a focusing switch, and the like.

The zoom lens 3 is driven by a zoom lens drive system 4 to change the magnification. The zoom lens drive system 4 transmits an operation signal of the zoom switch of the operation switch 2 from the operation switch 2 to the CPU 1. , The CPU 1 activates the zoom lens drive system 4, whereby the zoom lens 3 is driven to perform a zooming operation.

The zoom position of the zoom lens (i.e., the zoom position) associated with the zooming operation of the zoom lens 3 is detected by the zoom lens system position detecting means 5, and the detection result is used as focal length information. It is sent to CPU1.

When the distance measuring switch of the operation switch 2 is operated, an operation signal of the distance measuring switch is input to the CPU 1, and based on the signal, the CPU 1 drives and controls the distance measuring device 6 to measure the distance of the object (corresponding to the object distance). (Detection of the detected distance signal).

The distance measurement result of the distance measurement device 6, that is, the distance measurement information (distance signal) is input to the CPU 1.
Is input to the feeding amount calculating means 1a.

When the distance measurement information is input, the extension amount calculation means 1a calculates the extension amount of the focus lens 7 from the infinity position to the in-focus position based on the distance measurement information.

Based on the extension amount of the focus lens 7 up to the in-focus position calculated by the extension amount calculation unit 1a, the extension control unit 1b in the CPU 1 controls the extension of the focus lens 7 from the reference position.

The portion related to the feed control amount by the feed control means 1b will be described later.

8 is an E ² PROM (electrically erasable ROM) as storage means
In the zoom lens 3 in which the infinite position of the focus lens 7 changes with zooming, as shown in FIG. 2, the position of the zoom lens 3 (that is, the focal length)
The infinity position A of the focus lens 7 that changes depending on the focus position is electrically stored as a focus lens extension amount from the reference position B.

Further, as shown in FIG. 3, in the case of the zoom lens 3 in which the infinity position of the focus lens 7 is constant, the infinity position C of the focus lens 7 is electrically determined as the amount of extension of the focus lens 7 from the reference position D. The data is stored in the E ² PROM8.

Furthermore, in the case of a single focal length lens, as shown in FIG.
Is stored in the E ² PROM 8 as the focus lens extension amount from the camera.

Each G in FIGS. 2 to 4 indicates a close position of the focus lens 7, and H in FIGS. 2 and 3.
Indicates a zoom position corresponding to the focal length between the wide end and the tele end of the zoom lens 3.

Here, the delivery control means 1b will be described again. The extension control means 1b controls the extension of the focus lens 7 from the reference position to the in-focus position. In the extension control, in the zoom lens in which the infinite position of the focus lens 7 changes, FIG. The extension control of the focus lens 7 is performed from the indicated reference position B, and the control amount is a value obtained by adding the extension amount calculated by the extension amount calculating means 1a to the extension amount of the focus lens stored in the E ² PROM 8.

Also, as shown in the movement locus diagram of each lens in FIG. 3,
In the case of a zoom lens in which the infinite position C of the focus lens 7 is constant, the extension control of the focus lens 7
Starting from the reference position D, the control amount is controlled by the E ² PROM
A value obtained by adding the extension amount measured by the distance measuring device 6 and the extension amount calculating means 1a to the extension amount from the reference position D to the infinity position C of the focus lens 7 stored in 8.

Further, in the case of a single focal length lens, the extension control of the focus lens 7 to the in-focus position is performed starting from the reference position F in FIG. 4, and the control amount is stored in the E ² PROM 8. The amount of extension from the reference position F of the focus lens 7 to the infinity position E is added to the extension amount calculated by the extension amount calculating means 1a by measuring the distance by the distance measuring device 6.

In this manner, the zoom lens in which the infinity position of the focus lens 7 changes with zooming, the zoom lens in which the infinity position of the focus lens 7 is constant regardless of the change in the focal length, and the single focal length lens are respectively used. Accordingly, the drive of the focus lens driving system 9 is controlled by the feeding control means 1b.

The focus lens driving system 9 drives the focus lens 7 to focus on the basis of the extension control amount.

The operation of this embodiment thus configured will be described with reference to the flowchart of FIG.

The flowchart of FIG.
3 shows the flow of operation in the case of a zoom lens in which the infinite position changes with zooming.

In the flowchart of FIG. 5, step S11
, The first step of a release button (not shown) is turned on, the distance measuring switch included in the operation switch 2 is turned on, and in step S12, an ON signal of the distance measuring switch is input to the CPU 1 and the distance measuring device Starts the distance measurement operation.

The distance measurement value of the distance measuring device 6 is sent to the extension amount calculation means 1a in the CPU 1, and in step S13, the extension amount calculation means 1a
Based on this distance measurement value, as shown in FIG. 2, the amount of extension from the infinity position A of the focus lens 7 to the in-focus position is calculated to determine the amount of extension.

Next, in step S14, the CPU 1 controls the zoom lens driving system 4 based on the operation of the variable power switch included in the operation switch 2, and the zoom lens driving system 4 moves the zoom lens 3 to the long focal length side or the short focal length side. Driven.

The zoom position associated with the driving of the zoom lens 3 is detected by the zoom system position detecting means 5, and the detected value is
Sent to

Based on the position of the zoom lens 3 detected by the zoom lens system position detecting means 5, the amount of extension of the focus lens 7 from the reference position B to the infinity position A of the focus lens 7 is stored in the E ² PROM 8 stored at the time of infinite adjustment. In S15
The CPU 1 reads a value corresponding to the position of the zoom lens 3.

The reference position B is detected by a mechanical stopper or a switch at the end of a focus lens cam (not shown).

The infinite position adjustment of the focus lens 7 is performed by adjusting the focus lens 7 to the end of the mechanical stopper and the switch.
And the pulse motor (not shown) feeds out one pulse at a time, counts the number of pulses when the count reaches infinity by, for example, a photo interrupter, and stores the value in the E ² PROM 8. In this case, the above-mentioned adjustment is performed in advance at several points between the telephoto end and the wide end, and the values are stored.

The feed amount from the reference position B to the infinite position A of the focus lens 7 read from the E ² PROM 8 is input to the feed control means 1 b in the CPU 1.

Further, the feeding control means 1b calculates the feeding control amount from the reference position B of the focus lens 7 to the in-focus position by adding the distance value measured by the distance measuring device 6 to the feeding amount. I have.

In step S16, when the release button is pressed to the second stage, the release switch included in the operation switch 2 is turned on accordingly, and the CPU 1 receiving the ON signal
Causes the delivery control means 1b to calculate a delivery control amount in step S17. That is, the feeding control means
1b is the focus lens 7 obtained by the feeding amount calculating means 1a.
Of the focus lens 7 from the reference position B to the infinity position A at the desired zooming position read out from the E ² PROM and the focus lens drive. Control system 9.

The focus lens 7 is driven by the control of the focus lens drive system 9. As described above, the extension control amount of the focus lens 7 is performed by counting the pulses of the pulse motor and the photo interrupter.

After the focusing operation is completed by driving the focus lens 7 in this way, the shutter is operated to expose the film in step 18, and the photographing is completed in step 19.

The above description of the operation is for a zoom lens in which the infinite position of the focus lens 7 changes with zooming. However, in the case of a zoom lens in which the infinite position of the focus lens 7 is constant, the flowchart of FIG. This is in accordance with the operation flow shown in FIG. That is, in this case, the process is performed in the same procedure as the flowchart of FIG. 5 except that the process of step 14 in FIG. 5 by the zoom lens system position detecting means 5, that is, the zoom lens system position detecting process is omitted. Will be

In the case of a single focal length lens as well, the same operation as in the above embodiment is performed except that the processing of step 14 in FIG. 5 is omitted.

Thus, according to this embodiment, the release button 1
When the stage is turned on, the distance measurement value is obtained, and the focus lens 7
Is calculated from the infinity position of the focus lens to the in-focus position, and the position of the focus lens is detected from the reference position of the focus lens corresponding to the position of the zoom lens 3 by detecting the position of the zoom lens. E ² PROM that memorizes the feed amount to the infinite position at the time of infinite adjustment
Since it is configured to read from 8 and control the focus lens to be extended from the reference position to the in-focus position, infinite adjustment can be performed electrically, and no mechanical member is required,
The cost can be reduced, and the automatic adjustment of the infinite position can be easily performed.

In the above embodiment this regard, storage means such as E ² PROM 8 but is required, this type camera, in the storage such as a film counter storage means is used, it is possible to alternate the storage means, electrical components Does not lead to an increase.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

For example, it takes time to extend the focus lens 7 from the mechanical stopper end, which is the reference position, so that the focus lens 7 is extended from the reference position to the infinite position by turning on the camera power. Alternatively, the camera may be caused to perform the extension operation from the infinity position to the in-focus position, and to perform the extension operation to the reference position when the camera is turned off. Thus, when the power is turned off, the lens length becomes the shortest, and the camera can be made compact.

In this case, in the zoom lens in which the infinity position of the focus lens changes, after the magnification operation, infinite correction feeding is performed with the magnification.

〔The invention's effect〕

As described in detail above, according to the present invention, infinity adjustment of the focus lens can be performed electrically, expensive mechanical members are not required, cost can be reduced, and the camera can be downsized, The automatic adjustment is easy because it is possible to perform the automatic adjustment.On the other hand, the position accuracy can be improved by setting the reference position different from the infinite position to the part of the camera where there is no individual difference. Since the focus lens is extended from the position to the infinity position, the focusing operation can be performed quickly, and a focus lens control device that can be applied to an external device that can only detect the extension amount of the lens from the infinity position to the in-focus position. Can be provided.

The invention is not limited to the case of the first aspect of the present invention, in which the infinite position of the focus lens changes depending on the position of the zoom lens. And
In particular, according to the second aspect of the invention, since the amount of extension from the reference position to the infinity position of the focus lens is constant, the storage capacity of the storage means can be reduced by that amount, and the position detection and zooming of the zoom lens can be performed. Since the reading of the extension amount of the focus lens from the reference position to the infinite position according to the position of the lens can be omitted, simplification and cost reduction can be achieved as compared with the first aspect of the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of a focus lens control device according to the present invention, and FIG. 2 is an explanatory diagram of infinity position adjustment of a zoom lens in which the infinity position of the focus lens of the embodiment changes. , FIG. 3 is an explanatory diagram of the infinite position adjustment of the zoom lens in which the infinite position of the focus lens is constant unlike the above, FIG. 4 is an explanatory diagram of the infinite position adjustment of the single focal length lens, FIG. 3 is a flowchart showing the flow of the operation of the embodiment shown in FIG. DESCRIPTION OF SYMBOLS 1 ... Control means (CPU), 1a ... Extending amount calculating means, 1b ... Extending control means, 2 ... Operation switch, 3 ... Zoom lens, 4 ... Zoom lens drive system, 5 ... Zoom lens system position detecting means 6 ...... ranging apparatus, 7 ...... focus lens, 8 ...... E ² PROM, 9 ...... focus lens drive system.

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Claims (2)

(57) [Claims] 1. A storage means for electrically storing an infinite position of a focus lens that changes according to a zoom lens position as a focus lens extension from a reference position; a zoom lens system position detection means for detecting the zoom lens position;
A distance measuring device that measures a subject distance, and a feeding amount calculating unit that calculates a feeding amount from an infinity position to an in-focus position of the focus lens based on a distance measurement result by the distance measuring device;
The extension amount obtained by the extension amount calculation unit is added to the extension amount corresponding to the zoom lens position detected by the zoom lens system position detection unit among the extension amounts of the focus lens stored in the storage unit. A payout control means for performing a payout control of the focus lens as a payout control amount from the reference position to the focus position of the focus lens.
Extending the focus lens from the reference position to the infinity position corresponding to the zoom lens position detected by the zoom lens system position detection means out of the extension amount of the focus lens stored in the storage means,
Thereafter, the focus lens control device is configured to extend the focus lens from the infinite position to the in-focus position until the camera power is turned off, and to extend the focus lens to the reference position when the camera power is turned off. . 2. A storage means for electrically storing an infinity position of a single focal length lens or an infinity position of a focus lens of a zoom lens in which an infinity position of a focus lens is constant as a focus lens extension from a reference position. A distance measuring device that measures a subject distance; and a feeding amount calculating unit that calculates a feeding amount from an infinity position to a focusing position of the focus lens based on a distance measurement result of the distance measuring device;
A value obtained by adding the extension amount calculated by the extension amount calculation unit to the extension amount of the focus lens stored in the storage unit is set as an extension control amount from the reference position to the focus position of the focus lens. A feeding control means for controlling the feeding of the lens, and when the camera is turned on, the focus lens is fed from the reference position to the infinity position of the focusing lens stored in the storage means. A focus lens control device, wherein the focus lens control device is configured to perform an extension operation from the infinite position to the in-focus position until the power is turned off, and extend the focus lens to the reference position when the camera is turned off.