JPH0733206Y2 - Positioning device for shooting lens - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a photographing lens in which the photographing optical system can be set in a plurality of positions by moving the photographing optical system in the optical axis direction by a drive source such as a motor. The present invention relates to a position control device.

B. Conventional Technology A multifocal camera equipped with this type of position control device, for example, engages a guide cylinder rotatably supported by the camera body with a helicoid engraved on the inner surface and a helicoid of the guide cylinder on the outer surface. It has a lens barrel in which a helicoid is engraved and a photographic optical system is internally provided, a drive motor for rotationally driving the guide barrel, and an encoder interlocking with the guide barrel. The position of the lens barrel is determined by a position signal from the encoder. Know and move the lens barrel to a predetermined shooting position.

FIG. 13 shows an example of an encoder used in this type of position control device, in which a conductive pattern 72 is provided on the insulating substrate 1, and a brush 73 slides on the conductive pattern 72. Generally conductive pattern
72 is grounded and the brush 73 is connected to a power source, and the position of the brush 73, that is, the position of the lens barrel is known from the level of the signal obtained from the brush 73. For example, x on the conductive pattern 72
When the brush 73 sliding in the direction reaches the position shown by the solid line in FIG. 13, the brush 73 separates from the conductive pattern 72 and a high-level position detection signal is output from the brush 73 to detect the command position.

C. Problems to be solved by the device However, at such a command position, the brush 73
Since the conductive pattern 72 and the conductive pattern 72 are separated from each other with an extremely small distance (for example, the dimension a), the lens barrel is set to the camera even though the lens barrel is in the commanded position after the lens barrel is once set to the predetermined commanded position. Due to the vibration that acts, the brush 73 is made into a conductive pattern as shown by the broken line in FIG.
May contact 72. Therefore, the lens barrel is driven again until the motor is driven again and the brush 73 is separated from the conductive pattern 72. Since such a phenomenon occurs each time vibration is applied to the camera, the lens barrel is undesirably driven each time.

An object of the present invention is to provide a photographing lens position control device that solves the above-mentioned problems by not driving the lens barrel even if the detection position signal changes once the lens barrel is set to the command position. Especially.

D. Means for Solving Problems The present invention will be described with reference to FIG. 1, which is a diagram corresponding to claims. The position control device for a photographing lens according to the present invention includes a command means 102 for instructing the position of the photographing optical system 101. , Shooting optics 10
The position detecting means 103 for detecting the absolute position on the optical axis of 1 and the comparing means 104 for comparing the commanded position from the commanding means 102 and the detected position from the position detecting means 103 and outputting a coincidence signal when the two positions match. The driving means 105 for driving the photographing optical system 101 in the optical axis direction, and the photographing optical system 101 by operating the command means 102.
When the position is instructed, the comparing means 104 drives the driving means 105 until it outputs a coincidence signal, and when the comparing means 104 outputs the coincidence signal, the drive control means 106 that stops the driving of the driving means 105 is provided, The above-mentioned problems are caused by the comparison means 1
After 04 outputs a coincidence signal and the photographing optical system 101 is once set to the command position, it is driven even if the detection position of the position detection means 103 changes from the command position unless a new position is commanded from the command means 102. The control means is configured so as not to drive the driving means 105, which is solved.

E. Action When the position of the photographing optical system 101 is commanded by operating the command means 102, the drive means 105 is driven under the control of the drive control means 106. The comparing means 104 compares the commanded position from the commanding means 102 with the detected position from the position detecting means, and outputs a coincidence signal when the two positions coincide. When the coincidence signal is output, the drive control means 106 drives the drive means. Stop driving 105. As a result, the photographing optical system 101 is set at the command position. After the photographing optical system 101 is once set to the command position, even if the detection position of the position detecting means 103 changes from the command position, that is, even if the comparing means stops outputting the coincidence signal, the control of the drive control means 106 The drive means 105 below is not driven. After the photographing optical system 101 is once set to the command position, when the command unit 102 commands a new position, the driving unit 105 is driven until the coincidence signal is output again.

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

In FIG. 2 (a) showing the wide-angle photographing position of the lens barrel in cross section and FIG. 3 which is a view seen from the line III-III,
A guide tube 1 is rotatably supported by a camera body (not shown). A helicoid 1a is carved on the inner surface of the guide cylinder 1 up to almost the tip end thereof, and a gear 1b is formed on the outer peripheral surface thereof. A drive gear 5 rotationally driven by a motor 55 provided in the camera body meshes with the gear 1b.

Reference numeral 10 is a lens barrel that moves forward and backward with respect to the guide barrel 1 in the optical axis direction, and a helicoid 11 that meshes with the above-mentioned helicoid on the outer peripheral surface.
It has a lens barrel outer cylinder 11 in which a is engraved. A holding plate 12 is screwed to an inner middle portion of the lens barrel outer tube 11, and lenses 20a, 20b and 20c are provided on the front side of the holding plate 12 in the camera, and a supporting member 21, a focusing mechanism and a shutter driving mechanism are provided. The main photographing optical system 20 supported by a built-in holding cylinder 22 is screwed, the lenses 23a, 23b, and 23c are provided on the rear side of the camera, and the sub-photographing optical system 23 held by a holding member 24 is an optical path. It is provided so that it can be inserted and removed. The insertion / removal mechanism of the sub-photographing optical system 23 is well known and will not be described.

As shown in FIGS. 2 (a) and 3, the terminal support plate 30a is fixed to the support member 3 fixedly provided on the camera body side in correspondence with the outer peripheral wall of the distal end portion of the guide tube 1. The terminals 31, 32 and 33 are supported on the terminal support plate 30a, and the circuit board 4 on which the terminals 31 to 33 are slidably contacted is fixed to the peripheral wall of the tip end of the guide cylinder 1.

The circuit board 4 is composed of a flexible printed board and has a conductive pattern 41 shown in FIG. 4 (b).
41 is a ground pattern with which the COM terminal 31 is always in sliding contact. In the area A on the left side of Er indicating the reset position, the COM terminal 3
Only 1 is in contact with the conductive pattern 41, and a high level (hereinafter referred to as "H") signal is obtained from the X terminal 32 and the Y terminal 33 as shown in FIG. 4 (a).

In the region B between Ew indicating the wide-angle shooting position and Er indicating the reset position, the COM terminal 31 and the X terminal 32 are connected to the conductive pattern 4
In contact with 1, "L" and "H" signals are obtained from the X terminal 32 and the Y terminal 33, respectively. Et indicating the telephoto shooting position
In the area C between and Ew indicating the wide-angle shooting position, all the terminals 31 to 33 are in contact with the conductive pattern 41, so that the “L” signal is obtained from the X terminal 32 and the Y terminal 33. Further, in the area D on the right side of Et indicating the telephoto shooting position, the COM terminal 31 and the Y terminal 33 are in contact with the conductive pattern 41, so that “H” and “L” signals are obtained from the X terminal 32 and the Y terminal 33, respectively. To be

Next, the control system of this embodiment will be described with reference to FIG.

Reference numeral 51 is a control circuit having a well-known microcomputer including a RAM, a ROM, a CPU and the like. Reference numeral 52 is a main switch, and 53 is a changeover switch for setting the lens barrel to either a wide-angle photographing position or a telephoto photographing position. For example, a bush type self-reset type switch can be used. And
Depending on the current position of the lens barrel by turning on and off,
The lens barrel can be set to either position. These switches are provided on the camera body. Reference numeral 54 denotes the encoder described above, and signals are input to the control circuit 51 from the X terminal 32 and the Y terminal 33. Reference numeral 55 denotes a motor installed in the camera body as described above, which rotates the drive gear 5 shown in FIG. 2 to rotate the guide barrel 1, thereby guiding the lens barrel 10 to a predetermined position. That is, the drive is controlled by the motor drive signal output from the motor drive circuit 56 based on the processing procedure described later.

Next, the processing procedure of this embodiment will be described with reference to FIGS.

In FIG. 6, when the main switch 52 is turned on, step S100 is executed, and the lens barrel 10 is extended to the wide-angle photographing position by the program shown in FIG. In FIG. 7, the drive motor 55 is normally rotated in step S1, and step S2
The output X of the terminal 32 is determined to be "L" at step S3, and step S3
If the output Y of the terminal 33 is determined to be "L" at step S4,
Stops the drive motor 55. As a result, the lens barrel 10 is set at the position shifted from the area B to the area C in FIG. 4A, in other words, at the wide-angle shooting position (W). Next, at step S101, the W flag is set.

After that, the process proceeds to step S102, it is determined whether the half-push switch is turned on, and if the determination is affirmative, the well-known photographing procedure is executed in step S140, and after the photographing is finished, the process returns to step S102. In the shooting subroutine of step S140, the W flag, T
The current position of the lens barrel 10 is detected by reading the flag. Since the F-number of the lens is different when the lens barrel 10 is at the wide-angle shooting position and at the telephoto shooting position,
The appropriate exposure value is calculated according to each flag information, and then the aperture control and shutter speed control are performed to expose the film. When step S102 is denied, the routine proceeds to step S103, where it is determined whether or not the TW changeover switch 53 is turned on.
If a negative determination is made, the process returns to step S102, and if an affirmative determination is made, the process proceeds to step S104. In step S104, it is determined whether or not the W flag is set, and if affirmative, step
Proceed to S110.

That is, when the telephoto shooting is selected by the changeover switch 53, the lens barrel 10 is extended from the wide-angle shooting position to the telephoto shooting position by the program shown in FIG. In FIG. 8, the motor 55 is normally driven in step S11. And
When the output X is determined to be "H" in step S12 and the output Y is determined to be "L" in step S13, the motor 55 is stopped in step S14. As a result, the lens barrel 10 is set at the position where the region C shown in FIG. 4A is changed to the region D, in other words, the telephoto photographing position. Next, in step S105, the W flag is reset and the T flag is set.

If a negative decision is made in step S104, the operation proceeds to step S120.
That is, when the telephoto shooting is switched to the wide-angle shooting by the changeover switch 53, the lens barrel 10 is retracted from the telephoto shooting position to the wide-angle shooting position by the program of FIG. In FIG. 9, the motor 55 is reversely driven in step S21. When the output X is determined to be "L" in step S22 and the output Y is determined to be "H" in step S23, the motor reverse rotation is stopped in step S24. Next, in step S25, the motor 55 is driven to rotate normally. If the output X is determined to be "L" in step S26 and the output Y is determined to be "L" in step S27, the motor 55 is determined in step S28.
To stop. Next, in step S108, the T flag is reset and the W flag is set.

After step S105 or S108, the process proceeds to step S106. In step S106, it is determined whether or not the main switch is on. If the result is affirmative, the process returns to step S102, and if the result is no, the process proceeds to step S130. That is, when the main switch 51 is turned off, the lens barrel 10 is programmed by the program shown in FIG.
Is set to a reset position, that is, a position in which it is almost completely inserted into the camera body. In Figure 10, steps
When the drive motor 55 is reversed in S31 and the output X is determined to be "H" in step S32 and the output Y is determined to be "H" in step S33, the drive motor 55 is stopped in step S34. As a result, the lens barrel 10 is set at the position where the region B moves to the region A in FIG. 4A, in other words, the reset position. Next, in step S107, the T and W flags are reset and the R flag is set.

With such an operation, the lens barrel 10 set to the telephoto shooting position is set to the wide-angle shooting position as follows, whereby the lens barrel is always driven in one direction and the wide-angle and telephoto shooting positions are set. Can be set to prevent position displacement due to backlash of the power transmission system.

As shown in FIG. 11, the lens barrel at the telephoto photographing position is retracted by the reverse rotation of the motor, and moves to the position 7 ′ (the encoder 54 is moved to the position Ew ₁ (see FIG. 4 (b)) via the positions 6 and 7. After that, the motor is rotated in the normal direction to absorb the backlash between the positions 7'and 7 "(within the range between the positions Ew ₁ and Ew of the encoder 54), and the lens barrel 10 is further extended to move the encoder 54 to Ew. When the motor 55 is stopped when it is positioned, the lens barrel 10 stops at the position 3 and the wide-angle shooting position is set.

The shooting subroutine (step S140) in FIG.
As shown in FIG. 12, the current position of the lens barrel 10 is detected by the position signal from the encoder during shooting (step S41).
At the same time, the detected current position and the state of the flag are compared and determined (steps S42, S44), and if they do not match, the lens barrel 10 is driven so as to match the flag ((not shown) 45 , S46), and shooting may be performed with release in step S43. If the contact state between the encoder brush and the conductive pattern becomes unstable due to vibration and the lens barrel position itself deviates from the commanded position, this procedure ensures that the lens barrel is set correctly at the commanded position. Since shooting is performed from, it is possible to prevent shooting mistakes.

The present invention can also be applied to a position control device that drives an image pickup optical system for autofocus to a focus position. In this case, the command means corresponds to the focus detection circuit, and the position command depends on the defocus amount and its direction.

G. Effect of the Invention According to the present invention, when the lens barrel of a multifocal camera or the like is set at a plurality of positions, once the lens barrel is set to the command position, it is detected unless a new position is commanded. Since the lens barrel is not driven even when the position is different from the commanded position, there is no possibility that the lens barrel will repeatedly move undesirably near the commanded position.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram. 2 to 10 show the first embodiment, and the second embodiment
Figures (a) and (b) are cross-sectional views of a multifocal camera to which the present invention is applied. (A) shows a wide-angle shooting mode (b) shows a telephoto shooting mode, and Fig. 3 shows Fig. 2 (a). III-III plan view of FIG. 4, FIG. 4 (a) is a diagram showing the relationship between the position of the rotary encoder and the outputs of the X and Y terminals, and FIG. 4 (b) is a plan view of a conductive pattern forming the rotary encoder. FIG. 5 is a schematic configuration diagram of a control system, FIGS. 6 to 10 are flowcharts showing respective processing procedures, FIG. 11 is a diagram showing a positional relationship between an encoder position and a lens barrel, and FIG. 12 is a modified example. FIG. 13 is a flowchart for explaining the problem. 1: Guide tube, 1a, 1b: Helicoid 10: Lens barrel, 11a: Helicoid 20: Main shooting optical system, 23: Sub shooting optical system 31: COM terminal, 32: X terminal 33: Y terminal, 41: Conductive pattern 51: control circuit 52: main switch 53: changeover switch, 54: encoder 55: motor, 101: photographing optical system 102: command means, 102: position detection means 104: comparison means, 105: drive means 106: drive control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Nakamura 1-6-3 Nishi-oi, Shinagawa-ku, Tokyo Inside Oi Manufacturing Co., Ltd. of Japan Optical Industry Co., Ltd. (56) Reference JP-A-62-35309 (JP, A) Kai 60-91310 (JP, A) JP-A 52-114321 (JP, A)

Claims (3)

[Scope of utility model registration request] 1. A command means for commanding a position of a photographing optical system, a position detecting means for detecting an absolute position of the photographing optical system on an optical axis, a command position from the command means and a detection from the position detecting means. When the position of the photographing optical system is commanded by the operation of the command means, comparing means for comparing the positions and outputting a coincidence signal when the two positions match, a driving means for driving the photographing optical system in the optical axis direction, A position control device for a photographing lens, comprising: a drive control unit that drives the drive unit until the comparison unit outputs the coincidence signal, and stops the drive of the drive unit when the comparison unit outputs the coincidence signal. After the comparing means outputs the coincidence signal and the photographing optical system is once set to the command position, the position detecting hand is operated unless a new position is commanded by the command means. Position control device of the taking lens is detected positions said drive control means also vary from command position, characterized in that so as not to drive the driving means. 2. A device according to claim 1, wherein the drive control means stores the position of the photographing optical system when the photographing optical system is set at a command position, A position control device for a photographing lens, wherein the driving direction of the driving means is controlled based on the stored position when the commanding means is operated. 3. The apparatus according to claim 1 for utility model registration, wherein the drive control means stores the position of the photographing optical system when the photographing optical system is set at a command position. A position control device for a photographing lens, wherein an appropriate exposure value is calculated according to a stored position.