JP2009175398A - Lens device and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a focusing lens in the optimal reference position in response to a zoom lens position. <P>SOLUTION: This lens device/camera is provided with: a zoom lens driving means for driving a zoom lens, a focusing lens driving means for driving the focusing lens; a zoom lens position detecting means for detecting the zoom lens position; a storage means for storing a data of a reference position of the focusing lens with respect to the zoom lens position;a shift amount detecting means for detecting a shift amount ▵D from a target position of the zoom lens, when the zoom lens is driven up to the target position by the zoom lens driving means; a correction amount determining means for determining a correction amount ▵L from the reference position in response to the shift amount ▵D detected by the shift amount detecting means, referring to the data of the storage means; and a correction means for driving the focusing lens by the correction amount ▵L determined by the correction amount determining means, by the focusing lens driving means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens apparatus and a camera.

  A lens device is known in which a setting deviation due to temperature is corrected when a lens is set at a target position (see, for example, Patent Document 1).

Prior art documents related to the invention of this application include the following.
JP 2006-047749 A

When moving the zoom lens to the target position, setting deviation from the target position occurs due to the ambient environment such as temperature and humidity, so the focus lens is correctly focused even if it is set to the reference position corresponding to the target position of the zoom lens. There may not be.
In the conventional lens device described above, the set deviation amount is predicted and corrected based on the temperature. However, the set deviation amount due to the temperature is not always constant, and there is an error, and the influence of environmental changes other than the temperature is not excluded. There's a problem.

(1) According to the first aspect of the present invention, the zoom lens driving means for driving the zoom lens, the focus lens driving means for driving the focus lens, the zoom position detecting means for detecting the position of the zoom lens, and the position of the zoom lens A storage unit that stores data of a reference position of the focus lens, a shift amount detection unit that detects a shift amount from the target position of the zoom lens when the zoom lens driving unit drives the zoom lens to the target position; The correction amount determining means for determining the correction amount from the reference position according to the deviation amount detected by the deviation amount detecting means with reference to the data of the means, and the focus lens driving by the correction amount determined by the correction amount determining means Correction means for driving the focus lens by the means.
(2) According to a second aspect of the present invention, in the lens device according to the first aspect, the correction amount for the shift amount is determined according to the position of the zoom lens.
(3) The invention of claim 3 is a camera comprising the lens device according to claim 1 or claim 2, wherein the camera is turned on by the operating means or the landscape photographing mode is set by the operating means. When set, the zoom lens driving means drives the zoom lens with the tele end of the zoom lens as the target position, the deviation amount detecting means detects the deviation amount from the target position of the zoom lens, and the correction amount determining means detects the deviation. A correction amount from the reference position corresponding to the amount is determined, and the focus lens is driven by the focus lens driving unit by the correction unit by the correction unit.

  According to the present invention, the focus lens can be set to the optimum reference position according to the zoom lens position regardless of the position of the zoom lens.

  FIG. 1 is a diagram illustrating a configuration of a camera equipped with a lens device according to an embodiment. In FIG. 1, illustrations of camera components not directly related to the present invention are omitted. The imaging element 1 is an element that images a subject and converts it into an image signal, and a CCD, CMOS, or the like can be used. The image processing device 2 performs A / D conversion on the image signal from the image sensor 1 and performs various processes to generate digital image data.

  The operation input device 3 is various operation members and input devices. These operation members and input devices include a camera power switch, a shutter button half-press and full-press switch, a shooting mode switch, a zoom switch, and the like. The memory 4 is a non-volatile memory that stores various types of information, and previously stores focus deviation correction data, which will be described in detail later.

  The control device 5 includes a microcomputer (not shown), various memories, an A / D converter, and the like, and performs various sequence control and calculation of the camera including lens drive control.

  The zoom lens drive control device 6 is a device that controls the zoom lens 7 from the retracted end to the tele end through the wide end, and includes an actuator such as a pulse motor. When the zoom lens drive control device 6 receives the target position command from the control device 5, the zoom lens drive control device 6 drives and controls the actuator to drive the zoom lens 7 to the target position.

  The position detector 8 is a detector that detects the position of the zoom lens 7. In this embodiment, the amount of movement from the base point is measured using a photo interrupter to detect the current position. When moving from the current position to another position, a new position is detected by adding the amount of movement to the current position. The detector that detects the position of the zoom lens 7 is not limited to a photo interrupter, and the current position may be detected directly using, for example, an encoder.

  The focus lens drive control device 9 is a device that drives and controls the focus lens 10 from the closest end to the infinite end, and includes an actuator such as a pulse motor. Since the focus lens 10 is out of focus with the movement of the zoom lens 7, the focus lens drive control device 9 drives the focus lens 10 to a position corresponding to the movement position of the zoom lens 7, and is in focus with the movement of the zoom lens 7. Correct the deviation. Details of this correction operation will be described later.

  The display device 11 displays an image captured by the image sensor 1 using an LCD. The recording device 12 is an image recording medium such as a memory card that records captured images.

  FIG. 2 shows focus shift correction data for correcting the focus shift of the focus lens 10 accompanying the movement of the zoom lens 7, and shows the reference position of the focus lens with respect to the zoom lens position. This correction data is stored in the memory 4 shown in FIG. In FIG. 2, the horizontal axis indicates the zoom lens position, the position “0” corresponds to the wide end of the zoom lens 7, and the position “5” corresponds to the tele end of the zoom lens 7.

  For example, when a command signal for the target position “3” is sent from the control device 5 to the zoom lens drive control device 6, the zoom lens drive control device 6 drives the zoom lens 7 to the position “3”. On the other hand, the vertical axis indicates the reference position of the focus lens 10. In this embodiment, for example, the infinite end in the movement range from the closest end to the infinite end is set as the reference position.

  As described above, since the focus lens 10 is out of focus with the movement of the zoom lens 7, the focus lens 10 is driven to a position corresponding to the target position “3” of the zoom lens 7, that is, the position “A” shown in FIG. Then, the focus shift caused by the movement of the zoom lens 7 is corrected.

  However, when the zoom lens 7 is moved to the target position “3”, a setting deviation ΔD from the target position “3” may occur due to the ambient environment such as temperature and humidity. For this reason, even if the focus lens 10 is set to the position “A” corresponding to the target position “3” of the zoom lens 7, the zoom lens 7 is not actually set to “3”. The problem of not occurring.

  Therefore, in this embodiment, the actual setting position “3 + ΔD” of the zoom lens 7 is detected by the position detector 8, and the setting position of the focus lens 10 is corrected according to the setting deviation amount “ΔD”.

  As shown in FIG. 2, the primary interpolation is performed between the focus lens reference position “A” corresponding to the zoom lens position “3” and the focus lens reference position “B” corresponding to the zoom lens position “4” to zoom. When the lens position deviates from the target position “3” by the set deviation amount ΔD, a correction amount ΔL from the focus lens reference position “A” is obtained, and the focus lens 10 is set to the position “A + ΔL”.

  FIG. 2 shows an example in which the zoom lens 7 is driven at five positions from the wide end 0 to the tele end 5, but the target position of the zoom lens is not limited to this embodiment. Many more positions may be set. Alternatively, the position may be set finely for each step of the pulse motor that drives the zoom lens 7, and the focus shift accompanying the movement of the zoom lens may be finely corrected.

  FIG. 3 is a flowchart illustrating a zoom lens drive control program according to an embodiment. A microcomputer (not shown) of the control device 5 executes this program when driving the zoom lens 7 to an arbitrary target position.

  For example, immediately after the camera is turned on and activated, the zoom lens 7 in the retracted position is driven to the target position at the tele end. For example, when a predetermined shooting mode such as a landscape shooting mode is set, the zoom lens 7 is driven to the target position at the tele end. Alternatively, when an arbitrary target position is set by the zoom switch of the operation input device 3, the zoom lens 7 is driven to the target position. That is, every time a movement command to the target position is issued from the control device 5 to the zoom lens drive control device 6, the zoom lens drive control program shown in FIG. 3 is executed. Here, the case where the zoom lens position “3” shown in FIG. 2 is driven as the target position will be described as an example.

  In step 1, the zoom lens drive control device 6 is controlled to drive the zoom lens 7 to the target position “3”, and the movement amount is measured by the position detector 8. In the subsequent step 2, the focus lens drive control device 9 is controlled to drive the focus lens 10 to the reference position “A” corresponding to the target position “3” of the zoom lens 7.

  In step 3 after driving the zoom lens 7 and the focus lens 10, the current position of the zoom lens 7 is detected. The zoom lens position is a position obtained by adding the current movement amount detected by the position detector 8 to the previous zoom lens position. In step 4, the current position of the zoom lens 7 is compared with the target position “3”, and the presence or absence of the set deviation amount of the zoom lens 7 is confirmed. If the zoom lens 7 is overrun from the target position “3” and deviates by ΔD, the set deviation amount is present and the process proceeds to step 5.

  In step 5, the focus lens correction amount ΔL with respect to the set deviation amount ΔD from the target position “3” is obtained by primary interpolation with reference to the focus deviation correction data (see FIG. 2) stored in the memory 4. In step 6, the focus lens drive controller 9 drives the focus lens 10 by the correction amount ΔL to set the correct focus position “A + ΔL” corresponding to the zoom lens position “3 + ΔD”.

  Thus, in one embodiment, the reference position data of the focus lens 10 with respect to the position of the zoom lens 7 is stored in the memory 4 in advance, and the zoom lens is driven to the target position by the zoom lens drive control device 6. In some cases, the set deviation amount from the target position of the zoom lens 7 is detected, and the correction amount from the reference position corresponding to the detected set deviation amount is determined with reference to the data stored in the memory. Then, the focus lens 10 is driven and corrected by the focus lens drive controller 9 by the determined correction amount. As a result, regardless of the position of the zoom lens 7 that is moved, the focus lens 10 can be set to an optimum reference position corresponding to the zoom lens position regardless of changes in the surrounding environment such as temperature and humidity.

  Further, according to the embodiment, since the correction amount for the shift amount is determined according to the position of the zoom lens 7, the zoom lens is located at any position within the zoom lens movement range from the wide end to the tele end. Even when the lens 7 is moved, the focus lens 10 can be accurately corrected to the reference position with respect to the set deviation amount of the zoom lens 7.

  Furthermore, in one embodiment, when the camera is turned on by the operation input device 3 or a specific shooting mode (for example, landscape shooting mode) in which autofocus is disabled is set by the operation input device 3. The zoom lens drive control device 6 drives the zoom lens 7 with the telephoto end as the target position, detects a set deviation amount from the target position of the zoom lens 7, and an amount of correction from the reference position corresponding to the set deviation amount. The focus lens 10 is driven by the focus lens drive control device 9 for correction by the correction amount. Thereby, when the camera is turned on or when the specific shooting mode is set, the subject can always be accurately focused, and a focused image can be displayed on the display device 11.

  Note that the zoom lens drive control program shown in FIG. 3 is always executed when the zoom lens drive control device 6 controls the zoom lens 7 to the target position other than when the camera is turned on or when the specific shooting mode is set. Then, by performing the above correction processing, it is possible to realize an optimum focus position corresponding to the movement position of the zoom lens 7. When the automatic focus adjustment (AF) mode is set, the focus lens 10 is automatically adjusted after the zoom lens 7 is moved. Of course, the zoom lens drive control program shown in FIG. Also good.

  The present invention can be applied to any still camera, video camera, or lens apparatus including a zoom lens and a focusing lens, and the above-described effects can be obtained.

The figure which shows the structure of one embodiment The figure which shows the focus shift correction data of one embodiment The flowchart which shows the zoom lens drive control program of one embodiment

Explanation of symbols

3; operation input device, 4; memory, 5; control device, 6; zoom lens drive control device, 7; zoom lens, 8; position detector, 9; focus lens drive control device, 10;

Claims (3)

Zoom lens driving means for driving the zoom lens;
Focus lens driving means for driving the focus lens;
Zoom position detecting means for detecting the position of the zoom lens;
Storage means for storing data of a reference position of the focus lens with respect to a position of the zoom lens;
A deviation amount detecting means for detecting a deviation amount of the zoom lens from the target position when the zoom lens is driven to a target position by the zoom lens driving means;
A correction amount determination unit that determines a correction amount from the reference position according to the shift amount detected by the shift amount detection unit with reference to the data in the storage unit;
And a correction unit that drives the focus lens by the focus lens driving unit by a correction amount determined by the correction amount determination unit. The lens device according to claim 1,
The lens apparatus, wherein the correction amount with respect to the shift amount is determined according to a position of the zoom lens. A camera comprising the lens device according to claim 1 or 2,
When the camera is turned on by the operating means or when the landscape photographing mode is set by the operating means, the zoom lens driving means drives the zoom lens with the tele end of the zoom lens as a target position, The amount of deviation of the zoom lens from the target position is detected by the amount of deviation detection means, the amount of correction from the reference position corresponding to the amount of deviation is determined by the correction amount determination means, and the correction means determines the amount of correction. A camera characterized in that the focus lens is driven by the focus lens driving means by a correction amount.

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