JPH032707A - Lens position controller for zoom lens - Google Patents

Abstract

PURPOSE:To eliminate a need to adjust the angle of view and the focus point again at the time of reset operation by storing the lens position and returning a lens to this stored position after reset. CONSTITUTION:Values of zoom and focus counters for a lens 103 and a V lens 102 are stored in a storage element 125 through a bus line 126. It is decided whether the lens 103 is placed in the stored position or not, and the lens 103 is moved to the stored position if it is not placed in this position. The same operation is performed for the lens 102. When both lenses 102 and 103 are returned to stored positions together, the normal camera operation is started. Thus, it is unnecessary to adjust the lens position again though the reset operation is performed during operation, and lenses 102 and 103 are returned to original positions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a lens position control device for a zoom lens with reduced magnification change and focus adjustment functions.

[Prior Art] In a lens system equipped with variable power and focus adjustment functions, the position of the lens group changes due to changes in the focal length or object distance, and VPL (Variable Power L)
ens), the shape changes. Further, due to such changes in the position, shape, etc. of the lens group, the characteristics of the lens system itself also change. Therefore, in order to improve the operational performance of the control device of a lens system such as automatic focus adjustment, it is desirable to detect the state of the lens and take control appropriate to that state. Lens control technology using microcomputers and the like that can perform rough processing has become increasingly popular, and as a result, it has become possible to perform more precise lens position control.

As mentioned above, when trying to improve the operational performance of an automatic focus adjustment device, etc. by using a means for detecting the state of the lens and a means for performing complex and precise lens position control using a microcomputer, etc., the above-mentioned There is also a need to improve the resolution of devices for detecting lens conditions. A lens position detection device is a typical device for detecting the state of a lens. Conventionally, as a lens position detection device with high resolution, an encoder that generates a synchronous digital signal as the lens moves is often used.

Encoders that generate this digital signal can be broadly classified into two types, one of which is an absolute encoder that generates a unique signal corresponding to the position of the lens. The other type is an incremental encoder that outputs a Palma number proportional to the amount of movement of the lens.Due to cost and size, it is not suitable for consumer equipment. An incremental encoder is often used.

[Problems to be Solved by the Invention] However, when using an incremental encoder as in the conventional example described above, a counter for counting the number of pulses of the encoder must be included in a device that controls the lens position, including a microcomputer. In order to detect the absolute lens position, for example, immediately after turning on the power, move the lens to a predetermined reset position, reset the counter to a value corresponding to that reset position, and then It is necessary to start counting again.

Therefore, when performing the above reset operation such as when turning on the power,
Since the lens always moves, there was a drawback that it was not possible to set the angle of view and focus in advance, turn off the power, and standby for shooting.

An object of the present invention is to enable, for example, when the camera is turned off and then turned on for the next shooting, the lens is returned to the same position as when the previous shooting was completed, so that shooting can be started quickly. A lens position control device for a zoom lens is provided.

[Means for Solving the Problems] The gist of the present invention is to provide a first lens position detecting means for detecting the lens position of a first lens that performs magnification change, and a first lens position detecting means for detecting a lens position of a first lens that performs zooming; second lens position detection means for detecting the lens position of the second lens;
a first lens driving means for driving the first lens; a second lens driving means for driving the first lens;
a second lens driving means for driving the lenses; a lens position storage means for storing each lens position based on lens position information from the first lens position detection means and the second lens position detection means; a first operation of outputting a lens drive stop signal to the lens drive control means; and a second operation of returning the first and second lenses to predetermined reset positions. reset operation instruction means for alternately instructing operations, and the lens drive control means stores the lens position of each lens in the lens position storage means when the first operation is instructed from the reset operation instruction means. , and then when the second operation is instructed, the first and second lenses are moved from the reset position to the lens position stored in the lens position storage means. The present invention provides a lens position control device for a zoom lens, characterized in that it drives and controls two lens drive means.

[Function] The zoom lens lens position control device configured as described above has the following features:
When the reset operation is performed in the next operation, such as when the power is turned off, the lens position at that time is memorized and the lens is returned to the memorized position after the reset, even if the reset operation is performed. This eliminates the need to readjust the angle of view or focus.

[Embodiments] Embodiment 1 FIG. 1 is a block diagram showing Embodiment 1 of a lens position control device for a zoom lens according to the present invention.

101 is a fixed first lens group, 102 is a second lens group for zooming (hereinafter referred to as V lens), and 103 is a lens group for correcting changes in the focal plane due to zooming and adjusting focus. 3 lens group (hereinafter referred to as C lens), 104 is an aperture, 1
05 is a lens group of an imaging system, and these lens groups constitute a zoom lens of a video camera. 106 is C
An imaging surface of an imaging device such as a CD, 107 is an imaging surface 10
An amplifier circuit for amplifying the output of 8, 108 is a filter,
109 is a control unit consisting of a microcomputer and its peripheral circuits;
Aperture adjustment circuits 111 to 111 for determining the brightness of the image on the surface of 06 and adjusting the aperture 104 to obtain an appropriate brightness.
113 are the V lens 102, the C lens 103, and
A drive source for driving the aperture 104; 114 to 116 are drivers for driving the drive sources 111 to 113, respectively; 117 and 118 are rings that rotate as the lens 102 and C lens 103 move; 119 and 120;
121 and 122 respectively detect whether the lens 102 and the C lens 103 are at the reset position and output a detection signal to the control unit 109. Encoders 123 and 124 that rotate and output pulse information while rotating detect the pulse information output from the encoders 121 and 122, respectively, convert it into an electric signal, and output it to the control unit 109. Lens position detection 125 is a rewritable and readable memory element; 126 is a path line for mutual communication of data and control signals between the control unit 109 and the memory element 125;

FIG. 2 is a flowchart of a program processed inside the control unit 109 to control the lens positions of the lens 102 and the C lens 103, 201 is a block for starting the program, 202 is a block for zooming and automatic A program for performing normal operations such as focus adjustment, a program 203 for detecting whether the power switch of the video camera is turned off, and a program 204 for storing position information of the C lens 103 in the storage element 125. , 205 is a program for storing the position information of the V lens 102 in the storage element 125, 208 is a program for cutting off the power, 207 is a program for detecting whether the power switch is turned on, 209 is V, C A lens position detection device 12 that moves the multiple lenses to a predetermined reset position.
a program that resets the counters of the control unit 10 that count the output pulses of 3 and 124 to predetermined values;
210 is a memory element! From 25, the stored C lens 10
Program to read position 3, 211 is memory element 12
A program 212 reads the stored position of the V lens 102 from the program 21.
213 is a program to stop the movement of the C lens 103; 214 is a program to move the C lens 103 to the position read in 210;
A program that moves in the direction of the position read out, 21
5 is a program that determines whether the V lens 102 has moved to the position read by the program 211; 216 is a program that stops the movement of the V lens 102; 217
is a program to move the V lens 102 in the direction of the position read by the program 211, and 218 is a program to determine whether both Clv lenses have completed their movement to the positions stored in the programs 204 and 205, respectively.

The operation of this embodiment will be explained below based on FIG.

When the program starts in step 201, the normal camera operation of P2O2 is performed until the program (hereinafter abbreviated as P) 203 confirms that the power switch is turned off. P2O
When it is confirmed in step 3 that the power switch is turned off, the pulse information detected by the lens position detection devices 123 and 124 continues to be counted during normal operation. The values of the zoom and focus counters for each of the C lens and V lens (not shown) are stored in the storage element 125 via the pass line 126 at P2O4 and P2O5. When data storage is completed, the power to the circuit is cut off at P2O6, and the circuit waits until the power switch is turned on at P2O7. When P2O7 confirms that the power switch is plugged in, P2
At O9, move each lens to the predetermined reset position. When it is confirmed by the reset position detection devices 119 and 120 that the reset position has been reached, each lens is stopped and the two zoom and focus counters mentioned above are reset. Then, in P210 and P211, C, which was stored before the power was turned off, is stored in the memory element 125.
Read the position information of the V multi-lens. Next, in P212, it is determined whether or not the C lens is at the position memorized in P2O4, and if it has not yet reached that position, it is determined in P214.
Move the C lens toward the position stored in P2O4. Also, when the C lens reaches this position, P
213, the C lens is stopped. The same operation is performed for the V lens in P215 and P216. Then, in P218, it is determined whether the movement of both Clv lenses has been completed, and if either one has not been completed, the process returns to P212 and repeats the series of operations. C1 ■ When both lenses have returned to the memorized positions in P2O4 and P2O5, the program moves to P2O2.
Start normal camera operation.

By executing such a process, even if a reset operation is performed, each lens can be returned to the lens position immediately before the reset.

By the way, in this embodiment, the power switch of P2O7 is
The process from determining whether the n state has entered and determining P2O3 to actually allowing the power to be shut off using P2O6 is not possible unless there is a device that controls the on/off of the power supply outside of the computer for controlling the lens position. Conventionally, the device that controls the on/off of the power supply is often located outside the lens control computer, as shown in Fig. 3, and in this embodiment, the power supply system configuration as shown in Fig. 3 is used. The controller 109 includes the controller 109.

In Fig. 3, 301 is the power switch of the camera, 302
303 is a power supply circuit that turns on and off the power according to instructions from the microcomputer 302; 304 is a transmission line that transmits the state of the power switch 301 from the microcomputer 302 to the lens control computer;
305 is a transmission line for transmitting a signal to control the power supply circuit 303; 306 is a line for supplying power to the lens control computer; 307 is a transmission line for transmitting a signal to permit power cutoff from the lens control computer; 308; is a lens control computer. When the microcomputer 302 transmits the off state of the power switch 301 to the lens control computer 308, the computer 30
8, the program advances from P2O3 to P2O4. After processing P2O4 and P2O5, the computer 308 sends a power cut-off permission signal to the system control microcomputer 302 via the transmission path 307.
The same microcomputer 302 uses the transmission path 3.
05 to cut off the output of the power supply circuit 303.

Next, when the power switch 301 is turned on, power is first supplied from the microcomputer 302 to the lens control computer 308 from the power supply circuit 303 via the transmission line 305, and then the computer 30B supplies power to the lens control computer 308.
Execute the following program.

In addition, for the memory element 125, an element such as an E''FROM whose memory contents do not volatilize even if the power is cut off, or a P
A RAM is used with a circuit design such that power is supplied to the memory element 125 even with 2O6. Furthermore, R with power supply
It is also possible to use an AM card or the like as the memory element 125 and make it removable.

Embodiment 2 FIG. 4 is a block diagram of the control unit of Embodiment 2, and FIG. 5 is a flowchart showing the operation of Embodiment 2. In the flowchart shown in FIG. 5, P5O1 and P5O2 are C and V
A program 503 stores the values of the counters for detecting the lens position in the RAM in the lens control computer 308, and a program 503 shuts off the power to the extent that the contents of the RAM are not damaged.
From 7 onwards, processes similar to the flow shown in FIG. 2 are executed.

This embodiment has two modes: a mode in which normal arithmetic and discrimination processing is performed as a lens control computer (hereinafter referred to as normal mode), and a mode in which only the memory contents of RAM are retained and all other functions are stopped (hereinafter referred to as standby mode). ), and uses an element that can be switched to each mode. Further, in this embodiment, it is assumed that the memory element 125 shown in FIG. 1 is located inside the computer 308.

In FIG. 4, the power switch 301 is turned on.
In this state, a normal mode operation request is output from the microcomputer 302 to the lens control computer 308 via the transmission line 304. on the other hand,
When the power switch 301 is in the PO stomach eroff state,
A standby mode operation request is similarly output from the microcomputer 302 to the lens control computer 308. The power cutoff request signal from the microcomputer 302 to the power supply circuit 303 is output only when resetting all the states of the lens control computer 308 including the RAM. The power of the control computer 308 is not cut off.

At this time, a program as shown in FIG. 5 is executed inside the lens control computer 308.

That is, when program execution is started by P2O1, the values of the position detection counters of the C lens and V lens are always stored in the RAM in Pool and P5O2 unless it is confirmed that the power switch 301 is turned off in P2O3.
It will be stored again. Then, in P2O3, transmission line 3
When it is confirmed that the power switch 301 is turned off from the signal of 04, the RAM is not rewritten and the P5
At O3, it enters standby mode, stopping all functions except for holding RAM contents to save power consumption. Next P2
O of the power switch 301 from the signal of the transmission line 304 at O7
When n is confirmed, the programs from P2O3 onward are executed similarly to the first embodiment.

Embodiment 3 In Embodiment 1.2 above, a case was described in which the power was cut off, but the present invention can also be implemented using a similar process when resetting a camera equipped with a reset switch. It is.

FIG. 6 is a block diagram of the control section of the third embodiment, and FIG. 7 is a flowchart explaining its operation. In FIG. 6, 601 is a lens position return switch which is a camera reset switch, 602 is the same power source as the lens control computer 308, 603 is a resistor, and 604 is a ground potential.

Further, in FIG. 7, P7O1 is a program for reading the state of the lens position return switch 601.

In this embodiment, a switch 601 is used to select whether or not to perform the operation of returning the lens position after reset to the state before reset, as described in the first and second embodiments. Further, this embodiment is implemented by inserting the program 701 between P2O9 and P210 shown in FIG.

In FIG. 7, when the power is turned on at P2O3, the above-mentioned reset operation is executed. Thereafter, the value of the switch 601 is read by P701. switch 60
If the value of 1 is high level, the process from P21G onward is performed to restore the lens position, and if it is low level, it is determined that the lens position is returned to P2O2 without any restoration.
The conditions for determining 7O1 may be reversed.

According to this embodiment, since the photographer can select whether to return or not, it is possible to avoid prolonging the shooting standby time due to unnecessary operations.

[Effects of the Invention] As explained above, according to the present invention, by storing the lens position before moving the lens position to the reset position and moving the lens to the stored position after resetting,
Even if a reset operation is performed during operation, the lens can be returned to its original position without having to readjust the lens position.

Furthermore, according to the present invention, by providing a switch that prevents the return operation after reset from being executed, there is an effect that unnecessary waiting time after reset can be omitted.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the lens position control device for a zoom lens according to the present invention, FIG. 2 is a flowchart explaining its operation, FIG. 3 is a block diagram of the control section of the first embodiment, and FIG. FIG. 5 is a block diagram of the control unit of the second embodiment, FIG. 5 is a flowchart explaining the operation of the second embodiment, and FIG.
The figure is a block diagram of the control section of the third embodiment, and FIG. 7 is the third embodiment.
2 is a flowchart illustrating the operation of FIG. 101-105 Lens 106 Imaging surface 108 Filter 109 Control unit 1
11 to 113...Drive sources 114 to 116...Driver 123.124...Lens position detection means and 4 other persons Figure Figure Figure Figure 11 Procedural amendment October 1995 Display of incident Heisei No. 99 in 2007 Patent Issue ゛°-Helens False-/S.
18 (Name) (100) Agent for Canon Co., Ltd. Address: 330 Shigesu Building, 2-6-2 Marunouchi, Chiyoda-ku, Tokyo Corrections The following matters in the specification of this application We will correct it. Note 1: The scope of claims is amended as shown in the attached sheet. 2. On page 6, lines 14 to 16, replace the phrase ``instruct alternately to stop the drive'' with ``
It instructs the first operation of outputting drive and stop signals and the second operation of moving the first and second lenses to predetermined reset positions.'' 3. In the 1st to 3rd lines of page 7, the phrase "move to the reset position..." is corrected to "move to the lens reset position stored in the lens position storage means." Claim 1: A first lens position detection means for detecting the lens position of a first lens that performs magnification change; and a second lens position detection means that detects a lens position of a second lens that performs focus adjustment. , a first lens driving means for driving the first lens, a second lens driving means for driving the second lens, and lenses from the first lens position detection means and the second lens position detection means. A lens position storage means for storing each lens position based on position information, a lens drive control means for driving and controlling the first and second lens drive means, and a first lens drive control means for outputting a signal to stop the lens drive El to the lens drive control means. and a reset operation instruction means for instructing a second operation of moving the first and second lenses to a predetermined reset position, and the lens drive control means is configured to perform a first operation from the reset operation instruction means. When instructed, the lens position of each lens is stored in the lens position storage means, and when a second operation is then instructed, it is stored in the first and second thin 2G+/upper position storage means. A lens position control device for a zoom lens, characterized in that it controls drive of first and second lens drive means to move the lens to a lens reset position. 2. The lens drive control means includes first and second (7) L
2. The lens position control for a zoom lens according to claim 1, wherein the selection of whether or not to move the lens to the lens reset position stored in the lens position storage means is determined based on a signal from a switch. Device.

Claims (1)

[Scope of Claims] 1. A first lens position detection means for detecting the lens position of a first lens that performs magnification change, and a second lens position detection means that detects a lens position of a second lens that performs focus adjustment. means, a first lens driving means for driving the first lens, a second lens driving means for driving the second lens, a first lens position detecting means and a second lens position detecting means. a lens position storage means that stores each lens position based on lens position information; a lens drive control means that drives and controls the first and second lens drive means; and a first lens drive control means that outputs a lens drive stop signal to the lens drive control means. The operation and the first
and reset operation instruction means for alternately instructing a second operation to return the second lens to a predetermined reset position, and the lens drive control means receives the first operation from the reset operation instruction means. and stores the lens position of each lens in the lens position storage means, and then when a second operation is instructed, the first and second lenses are moved from the reset position to the lens position stored in the lens position storage means. A lens position control device for a zoom lens, characterized in that the first and second lens driving means are drive-controlled to move the first and second lenses. 2. The lens drive control means determines whether or not to move the first and second lenses from the reset position to the lens position stored in the lens position storage means, based on a signal from the switch. The lens position control device for a zoom lens according to claim 1.