JP5523074B2 - LENS DEVICE AND IMAGING DEVICE - Google Patents

Description

  The present invention relates to a lens device such as a broadcasting lens having an autofocus function, and more particularly to a lens device including a wiper for wiping off water droplets and the like adhering to an optical surface.

  In recent years, video output from video cameras has shifted to a high-definition HDTV system, and since the depth of field is shorter than that of the conventional system, it is difficult to perform a focus operation.

  Therefore, in recent broadcasting lenses, autofocus has been introduced, and a phase difference detection method and a contrast detection method such as Patent Document 1 are known. In addition, as in Patent Document 2, there has been proposed a method of detecting a focus state using a plurality of imaging elements arranged with different optical path lengths.

  On the other hand, in a broadcasting lens or a pan head system that performs remote operation, the wiper can remove deposits on the optical surface of the photographing optical system so that raindrops and snow do not interfere with photographing.

Japanese Patent Publication No. 08-003579 JP-A-55-76312

  In a lens apparatus such as a broadcasting lens, a TTL system that detects a focused state by using a light beam that has passed all or part of a photographing optical system is generally used. In such a photographing lens, if the wiper passes the photographing range at the time of detecting the in-focus state, the in-focus position may be calculated closer to the wiper, and the focus may be greatly shifted. In particular, in video shooting of fast-moving subjects such as sports, it is required to reduce the autofocus response time as much as possible. However, there is a possibility that the follow-up performance to the subject may deteriorate due to the influence of the wiper. . Further, even in close-up shooting on the wide-angle side, the subject and the wiper are relatively close, so the focus shift is conspicuous.

  An object of the present invention is to provide a lens apparatus and an imaging apparatus that can prevent a focus shift due to a wiper passing through an imaging range when an in-focus state is detected, and perform appropriate autofocus control. .

The lens apparatus of the present invention includes a photographing optical system including a focus lens group, a focus detection unit that detects a focus state with respect to a subject using a light beam that has passed through at least a part of the photographing optical system, and the focusing device. based on the detection result of the detecting means, there by the lens apparatus having a control means for outputting a signal for driving the focus lens group, and a wiper to wipe the surface of the optical surfaces disposed on the object side of the imaging optical system And a memory for storing a target position of the focus lens group based on a detection result of the focus detection unit, and the control unit is configured to start driving the wiper when the wiper is located in the photographing range. Whether the difference between the target position of the focus lens group and the target position of the focus lens group when the wiper is in the shooting range is within a predetermined range. If the difference is determined to be outside the predetermined range, the focus lens group is not driven to the target position of the focus lens group when the wiper is within the shooting range, and the difference is When it is determined that it is within a predetermined range, the focus lens group is driven to a target position of the focus lens group when the wiper is positioned within the photographing range .

  According to the present invention, it is possible to provide a lens apparatus and an imaging apparatus capable of preventing focus shift due to the wiper passing through the imaging range when detecting the in-focus state, and performing appropriate autofocus control. .

Schematic diagram of imaging device of the present invention Block diagram of the imaging apparatus of the present invention The flowchart explaining the control content of the lens apparatus of the reference example 1 of this invention. The flowchart explaining the control content of the lens apparatus of the reference example 2 of this invention. Explanatory drawing of the position of the wiper of the lens apparatus of this invention The flowchart explaining the control content of the lens apparatus of the Example of this invention. The flowchart explaining the control content of the lens apparatus of the reference example 3 of this invention. The flowchart explaining the control content of the lens apparatus of the reference example 4 of this invention. Explanatory drawing of the display pattern of the monitor of the imaging device of this invention

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[Reference Example 1]
FIG. 1 is a schematic diagram of an imaging apparatus including the lens device according to Reference Example 1 of the present invention. The photographing optical system of the lens apparatus (photographing lens) 100 includes a focus lens group 2, a zoom lens group 3, a prism 4 that splits a focus detection light beam and a photographing light beam, a variable power lens group 5, and a relay lens group 6. It has. The focus lens group 2 is a lens group that moves the imaging position by moving in the optical axis direction, and the zoom lens group 3 is a lens group that changes the focal length by moving in the optical axis direction.

  The light beam that has passed through the focus lens group 2 and the zoom lens group 3 that are part of the photographic optical system is split into two light beams by the prism 4. The photographing light beam divided by the prism 4 passes through the prism 4, passes through the variable power lens group 5 and the relay lens group 6, and reaches the CCD (imaging device) 1 of the camera body 200. The focus detection light beam divided by the prism 4 is reflected by the prism 4 and reaches the detection sensor 8 that detects the in-focus state via the detection lens group 7.

  The detection lens group 7 and the detection sensor 8 of this embodiment constitute a phase difference detection type focus detection system (focus detection means), and a pair of light beams that have passed through the detection lens group 7 correspond to the respective light beams. The incident light enters the photoelectric conversion element of the detection sensor 8. A signal corresponding to the amount of focus deviation is generated as a detection result of the focus detection means by the correlation calculation of the light amount distribution obtained from these photoelectric conversion elements.

  The focus lens group 2 is driven in the optical axis direction by a motor 9 via a screw feed mechanism (not shown) such as a helicoid. The motor 9 is provided with a focus position sensor 10 that detects the position of the focus lens group 2.

  In the zoom lens group 3, the lens group of the variator (left side of the figure, object side) and the compensator (right side of the figure, image side) is driven by the motor 11 through the cam shaft 12 in the optical axis direction. The motor 11 is provided with a zoom position sensor 13 that detects the position of the zoom lens group 3.

  The variable power lens group 5 is a lens group in which a standard lens group or an extender lens group is selectively inserted into an optical path by a rotation mechanism (not shown).

  A diaphragm 14 for changing the F number is disposed between the zoom lens group 3 and the prism 4. On the object side of the lens apparatus 100, there are a protective glass plate 15 for protecting the lens, and a protective glass plate 15. A wiper 16 for removing water droplets and foreign matters on the surface, and a motor 17 for driving the wiper 16 are provided. The wiper 16 is made of a soft material such as rubber to wipe the surface of the optical surface of the protective glass plate 15 and is driven by a motor 17 via a link mechanism (not shown). The wiper 16 is retracted outside the shooting range on the surface of the protective glass 15 in the non-driven state, and when an input signal is transmitted from a wiper switch 21 described later, the wiper 16 wipes off water droplets and foreign matters in the shooting range. The surface of the protective glass plate 15 is reciprocated.

FIG. 2 is a block diagram of an imaging apparatus including the lens apparatus according to Reference Example 1 of the present invention.

  A signal obtained by the detection sensor 8 for detecting the in-focus state, a signal concerning the position of the focus lens group 2 in the optical axis direction obtained by the focus position sensor 10, and a zoom lens obtained by the zoom position sensor 13 A signal related to the position of the group 3 in the optical axis direction is converted into a digital signal by the A / D converter 18 and input to the lens CPU 19.

  The AFSW (AF switch) 20 is a switch for performing autofocus control, and can select two types, a mode in which autofocus is always performed and a mode in which autofocus is temporarily performed. The wiper switch (wiper SW) 21 is a switch for driving the wiper 16.

  The lens CPU 19 generates a focus control signal, a zoom control signal, and a wiper control signal. These control signals are converted into analog signals by the D / A converter 22 and then output to the focus drive circuit 23, zoom drive circuit 24, and wiper drive circuit 25. The motor 9 converts the driving force to drive the focus lens group 2, the motor 11 converts the driving force to drive the zoom lens group 3, and the motor 17 converts the driving force to drive the wiper 16.

  The memory 26 stores a focus position (target position) calculated based on the detection value output from the detection sensor 8, and the lens CPU 19 controls temporary writing, reading, and erasing.

  The monitor 27 displays an image generated by the camera CPU 28 based on the electrical signal of the CCD 1. The lens CPU 19 calculates the difference between the focus position and the imaging position from the detection value of the detection sensor 8 and the output values of the focus position sensor 10 and the zoom position sensor 13, and outputs information on the in-focus state obtained from the difference. doing. The monitor 27 displays the contents corresponding to the in-focus state, and also displays information related to the in-focus state detection area output from the lens CPU 19, the F number, the wiper driving state, and the like.

  FIG. 9 is an example of the display pattern of the monitor 27. On the display unit 29 of the monitor 27, a pattern 30 indicating the detection area of the focused state, a pattern 31 indicating the focused state, a pattern 32 indicating the F number, and a pattern 33 indicating the driving state of the wiper are displayed. Yes. Information on each display pattern of 30, 31, 32, and 33 is transmitted from the lens CPU 19 to the camera CPU. The pattern 31 indicating the in-focus state in the in-focus state detection area has a ▽ mark in the downward direction when the image forming position is on the front side, and a △ mark in the upward direction when the image forming position is on the rear side. When the imaging surface is within the depth of focus, the ■ mark is displayed. Reference numeral 32 represents the F number of the lens with a numeral, which is displayed as “F2.8” in the figure. Reference numeral 22 indicates the state of the wiper in characters. When the wiper is being driven, for example, “W ON” is displayed, and when the wiper is stopped, for example, “W OFF” is displayed. As will be described later, “W CANCEL” is displayed when the wiper drive is invalidated, and “W HOLD” is displayed when the wiper is on hold.

  Thus, by displaying the state of the photographing lens on the monitor 27, the photographer can grasp the state of the photographing lens. The wiper status display is particularly necessary when the wiper drive is disabled or put on hold.

FIG. 3 is a flowchart for explaining the control contents of the lens apparatus of Reference Example 1. When the lens apparatus 100 is powered on, the register and memory of the lens CPU 19 are initialized in step 101. Next, in step 102, it is determined whether the AF switch 20 is ON. If the AF switch 20 is ON, the target focus position Fx that is a target for controlling the focus is initialized to the current focus position F. To step 103. When the AF switch 20 is OFF, the process returns after the initialization in step 101.

  When the AF switch 20 is ON, the process further proceeds to step 103 where the detection sensor 8 reads a pair of image signals corresponding to the pair of light beams. Next, the process proceeds to step 104, and after correcting the pair of image signals by the aberration of the optical system, a digital filter calculation process for removing a specific frequency component is executed. In step 105, a known image interval detection process is performed on the pair of image signals to calculate the phase difference amount X from the image interval at the time of focusing and the current image interval.

Subsequently, the process proceeds to Step 106 and Step 107, and the zoom position Z and the focus position F detected by the zoom position sensor 13 and the focus position sensor 10 are acquired. In step 108, a defocus amount (focus shift amount) D necessary for focusing is calculated based on the data X, Z, and F acquired in steps 105 to 107. The defocus amount D is the distance between the imaging surface of the CCD 1 and the actual imaging surface, and is different from the mechanical movement amount of the focus lens group 2. The defocus amount D is obtained by the following equation.
D = k1 * (X−f1 (Z, F))
k1 is a coefficient for converting the phase difference amount into the defocus amount, and is calculated as a fixed value. The function f1 is an offset amount of a phase difference amount determined by the zoom position Z and the focus position F, and is stored in a memory (not shown) as table data. Both k1 and f1 are determined by the optical configuration of the focus lens group 2, the zoom lens group 3, and the detection lens group 7.

In step 109, the defocus amount D is converted into an amount corresponding to the positional difference of the mechanical focus lens group 2. The focus position difference ΔF is calculated using the following equation.
ΔF = D * f2 (Z, F)
The function f2 (Z, F) is a coefficient that is determined by the zoom position Z and the focus position F, and converts the defocus amount, which is an optical focus position difference, into a corresponding mechanical focus position difference. Data is stored in a memory (not shown).

  In step 110, it is determined whether the wiper switch (wiper SW, W SW) 21 is ON. When the wiper switch is ON, the process proceeds to step 111, the focus position difference ΔF obtained in step 109 is deleted, and no output to the focus drive circuit 23 is performed. In step 112, when the wiper switch 21 is ON, a command is issued to the wiper drive circuit 25 via the D / A converter 22, and the wiper 16 is driven via the motor 17 and the link mechanism.

  The wiper 16 moves from the retracted position, which is the initial position before the start of driving, to the opposite side through the photographing range of the protective glass 15, and again passes through the photographing range and returns to the retracted position. In step 113, the wiper drive is finished in response to the wiper 16 returning to the retracted position, which is the initial position, and the process returns to step 102 again to repeat the same processing.

  When the wiper switch 21 is OFF, the process proceeds to step 114. Therefore, a control signal for driving the focus lens group 2 to the target focus position Fx calculated from the focus position difference ΔF obtained in step 109 is generated, and in step 115, the focus drive circuit is connected via the D / A converter 22. A drive signal is output to 23. Next, the focus lens group 2 is driven to the target focus position Fx via the motor 9 and the screw feed mechanism. And it returns after the initialization of step 101 again, and repeats the same process.

  As described above, since it is determined whether or not the focus lens group 2 can be driven by autofocus based on the state of the wiper switch 21 (drive state of the wiper 16), focusing operation by autofocus is prohibited when the wiper 16 is driven. Is done. Therefore, it is possible to prevent a focus shift caused by the operation of the wiper 16.

  In this embodiment, the target focus position Fx is calculated by the phase difference detection method. However, the target focus position Fx is calculated by the contrast method based on the photographed image obtained from the light beam that has passed through the entire photographing optical system. In-focus detection means can be used.

  In the present embodiment, the focus lens group 2 is determined based on the state of the wiper switch 21 after detecting the in-focus state of the subject, but only when the wiper switch 21 is OFF. It may be configured to detect the in-focus state.

[Reference Example 2]
FIG. 4 is a flowchart for explaining the control content of the lens apparatus of Reference Example 2.

When the lens apparatus 100 is powered on, the lens CPU 19 proceeds to step 201 and initializes the registers, memories, etc. in the lens CPU 19 as in the first embodiment . Next, the routine proceeds to step 202, where it is determined whether the AF switch 20 is ON. When the AF switch 20 is ON, the target focus position Fx that is a target for controlling the focus is initialized to the current focus position F. To step 203. When the AF switch 20 is OFF, the process returns to step 202.

Steps 203 to 209 are the same as steps 103 to 109 in Reference Example 1. Accordingly, in the same manner as in Reference Example 1, in step 209, a focus position difference ΔF corresponding to the defocus amount D up to the in-focus position is generated.

  In the next step 210, it is determined whether or not the wiper 16 is moving within the photographing range of the surface of the protective glass 15. Determination of whether or not the wiper 16 is moving within the shooting range will be described with reference to FIG.

  FIG. 5 is a schematic view when the protective glass 15 is viewed from the front of the lens. The wiper 16 is stopped at the left initial position (retracted position). When the wiper switch 21 is switched to ON, the wiper 16 moves and moves to the retracted position on the right side of FIG. Then, it passes through the photographing range again and returns to the left retracted position. Since the wiper 16 reciprocates at a constant cycle, when the time when the wiper switch 21 is turned on is T0, the time from when the wiper switch 21 is turned on until the wiper 16 is started is T1, and then reaches the photographing range. T2 is the time to the end, T3 is the time to pass through the imaging range, and T4 is the arrival time to the right retreat position. Similarly, T5, T6, T7, and T8 are set for the return path, and the wiper 16 returns to the initial position (retracted position) again at the drive end time Tw.

  In step 210, the lens CPU 19 determines whether the wiper 16 is being driven. When the wiper 16 is being driven, the time T0 when the wiper switch 21 is turned on is calculated. If it is determined that the time ΔT from the time T0 to the present time is within the time T3 and T6, the process goes to step 211. move on.

  When the wiper 16 is not being controlled, or when ΔT is outside the time T3 and T6, the process proceeds to step 213. In step 213, a control signal for driving the focus lens group 2 to the set target focus position Fx is generated, and in step 214, a command signal is output to the focus drive circuit 23 via the D / A converter 22. Next, the focus lens group 2 is driven to the target focus position Fx via the motor 9 and the screw feed mechanism. And it returns to step 202 again and repeats the same processing.

  In step 211, it is determined whether or not the target focus position Fx calculated from the focus position difference ΔF is within the movement range of the focus lens group 2. If it is determined that the target focus position Fx is outside the movement range of the focus lens group 2, the process proceeds to the next step 212. In step 212, the focus position difference ΔF obtained in step 209 is deleted to invalidate the focusing operation, and no command signal is output to the focus drive circuit 23. When it is determined that the target focus position Fx is within the movement range of the focus lens group 2, the process proceeds to steps 213 and 214, the focus lens group 2 is driven to the target focus position Fx, and the process returns after the initialization of step 201 again. Repeat the same process.

  In the present embodiment, the position of the wiper 16 is obtained based on the elapsed time from the time T0 when the wiper switch 21 is turned on. However, the output of a sensor that detects the position of the wiper 16 may be used.

As described above, since whether or not the focus lens can be driven by autofocus is determined based on the position of the wiper 16, it is possible to shorten the time during which the focus drive is limited as compared with the first reference example . When the target focus position calculated during the driving of the wiper 16 is determined to be an abnormal value outside the movement range of the focus lens group 2, the operation of the wiper 16 and the lens are performed to invalidate the driving of the focus lens group 2. The focus shift caused by raindrops or snow attached to the surface can be reliably prevented. As in Reference Example 1, Reference Example 2 can use a well-known focus detection method. However, in contrast detection method, the calculation of the target focus position outside the movement range of the focus lens group is largely focused. Since the image signal is shifted and the sharpness is low, it may be difficult to determine whether it is the near side or the infinite side. In this case, it is preferable to set the determination in step 211 outside the moving range of the focus lens group without limiting to the close side.

[Example]
Figure 6 is a flow chart for explaining the contents of control of the lens device of Example.

When the power of the lens apparatus 100 is turned on, the process proceeds to step 301, initializes a similarly lens CPU19 internal registers, memory and the like as in Reference Example 1. Next, the routine proceeds to step 302, where it is determined whether the AF switch 20 is ON. When the AF switch 20 is ON, the target focus position Fx that is a target for controlling the focus is initialized to the current focus position F. The process proceeds to step 303. When the AF switch 20 is OFF, the process returns after the initialization in step 301.

Steps 303 to 309 are the same as steps 103 to 109 of Reference Example 1. In step 310, the target focus position data calculated from the focus position difference ΔF is temporarily stored in the memory 26. When a certain amount of data is stored in the memory 26, the old data is deleted in order. The memory 26 is configured to be able to store data of a time longer than at least the wiper driving time Tw of FIG.

In Step 311, as in Step 210 of Reference Example 2, it is determined whether or not the wiper 16 is moving in the photographing range on the surface of the protective glass 15. When the wiper 16 is moving within the photographing range of the protective glass 15 in step 311, the process proceeds to step 312. When the wiper is not driven or when the wiper 16 is out of the shooting range, the process proceeds to step 316. In step 316, a control signal for driving the focus lens group 2 to the set target focus position Fx is generated. Next, at step 317, the data of the target focus position Fx is temporarily stored in the memory 26. In step 318, a command signal is output to the focus drive circuit 23 via the D / A converter 22. Then, the focus lens group 2 is driven to the target focus position Fx via the motor 9 and the screw feed mechanism. And it returns to step 302 and repeats the same process.

In step 312, the target focus position data stored in step 317 is read. The data to be read is the target focus position when the wiper switch 21 in FIG. 5 is turned on (before the wiper drive is started), that is, at T0. In step 313, the target focus position F0 at the time T0 is compared with the current target focus position Fx. Next, in step 314, it is determined whether the difference between F0 and Fx is within an allowable range (predetermined range). As a setting criterion for the allowable range, a range in which focus deviation is allowed, for example, a range obtained by combining the front and rear depths of field Hf and Hb at the focus position F is set with a coefficient. The depth of field is a value determined by the zoom position Z, the focus position F, and the F number, and the values of Hf and Hb are greatly different depending on these values. The value is small when Fno is small on the telephoto side, and the value is large when Fno is large on the wide angle side. The allowable range L is calculated by the following formula.
L = k2 (Hf + Hb)
The coefficient k2 is stored as table data in a memory (not shown). The value of L decreases in proportion to Hf and Hb, and decreases as the telephoto side or Fno decreases, and increases as the wide angle side or Fno increases. Further, if the value of k2 is set to be small, there is a possibility that the actual movement of the subject may exceed L. Therefore, it is preferable that the value of k2 is set to be large while allowing a slight focus shift.

  When the difference between F0 and Fx exceeds the allowable range L, the process proceeds to step 315, the focus position difference ΔF obtained in step 309 is deleted, the flow of the focusing operation is invalidated, and the command to the focus drive circuit 23 is Not performed. When the difference between F0 and Fx falls within the allowable range L, the process proceeds to step 316, and after performing the processes of steps 316 to 318 described above, the process returns again after the initialization of step 301, and the same process is repeated.

As described above, since the driving of the focus lens group 2 for autofocusing is invalidated only when the difference between the start of driving of the wiper and the current target focus position exceeds the allowable range, the focusing operation on the subject is performed. It becomes easy to continue. Incidentally, examples, in the same manner as in Reference Example 1 and 2, it is possible to use known focus detection method.

[Reference Example 3]
FIG. 7 is a flowchart for explaining the control content of the lens apparatus of Reference Example 3 .

  When the wiper switch 21 is turned on in step 401, it is determined in step 402 whether the AF switch 20 is turned on. When the AF switch 20 is ON, the process proceeds to step 403, the wiper drive is invalidated, and the process returns to step 401. When the AF switch 20 is OFF, the process proceeds to step 404, where a drive signal is output to the wiper drive circuit 25, and the wiper 16 is driven via the motor 17 and the link mechanism. In step 405, the wiper drive is terminated, and the process returns to step 401.

  As described above, since the wiper 16 is not driven during the focusing operation, it is possible to prevent a focus shift by the wiper 16. Note that the autofocus detection method is not limited to the phase difference detection method, and a known focus detection method such as a contrast detection method can be used.

[Reference Example 4]
FIG. 8 is a flowchart for explaining the control content of the lens apparatus of Reference Example 4 .

  When the wiper switch 21 is turned on in step 501, it is determined in step 502 whether the AF switch 20 is on. When the AF switch 20 is ON, the process proceeds to step 503, the wiper drive is suspended, and the process returns to step 502. Thereafter, when the AF switch 20 is turned OFF, the process proceeds to step 504, where a drive signal is output to the wiper drive circuit 25, and the wiper 16 is driven via the motor 17 and the link mechanism. In step 505, the wiper drive is terminated, and the process returns to step 501.

  As described above, the drive of the wiper 16 is suspended during the focusing operation, and the wiper 16 is driven after the focusing operation is completed. Note that the autofocus detection method is not limited to the phase difference detection method, and a known focus detection method such as a contrast detection method can be used.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

DESCRIPTION OF SYMBOLS 1 Image pick-up element 2 Focus lens group 3 Zoom lens group 8 Detection sensor 9 Motor 10 Focus position sensor 11 Motor 13 Zoom position sensor 15 Protective glass plate 16 Wiper 17 Motor 100 Lens apparatus 200 Camera body

Claims (2)

A photographing optical system including a focus lens group;
Focus detection means for detecting a focus state with respect to a subject using a light beam that has passed through at least a part of the photographing optical system;
Based on the detection result of該合focus detecting means, and control means for outputting a signal for driving the focusing lens group,
A lens apparatus having a wiper for wiping the surface of the optical surfaces disposed on the object side of the imaging optical system,
A memory for storing a target position of the focus lens group based on a detection result of the focus detection unit;
When the wiper is located in the shooting range, the control means includes a target position of the focus lens group before the wiper starts driving, and a target position of the focus lens group when the wiper is located in the shooting range. If the difference is determined to be within a predetermined range, and it is determined that the difference is outside the predetermined range, the focus lens group is moved to the focus when the wiper is positioned within the shooting range. When it is determined that the difference is within a predetermined range without driving to the target position of the lens group, the focus lens group is moved to the target position of the focus lens group when the wiper is located within the photographing range. A lens device that is driven . Imaging device comprising the lens device according, further comprising an image sensor in claim 1.

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