JP2002006199A - Lens-driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens-driving device for a camera shortening the time for focusing by moving the lens back and forth. SOLUTION: The lens-driving device has a lens-supporting member 40, a driving mechanism 50, which drives the lens-supporting member freely back and forth to move the lens 30, a detecting member 90, which detects the starting point of lens moving operation by the driving mechanism, and a controlling member which controls the operation of the driving mechanism based on the output signal of the detecting member. The lens-supporting member 40 has two settings, where the wide-angle-side standby position for the wide-angle photographing mode and the telephoto-side standby position for the telephotographing mode, varying with the amount of lens movement. Before the shutter release operation, the detecting member 90 detects either of the two standby positions (the end face 91a or 91b of the detecting plate 91) as the starting point. Based on the detected signal, the driving mechanism is controlled to allow the lens-movement operation to start from either point, thus reducing the controlling time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lens driving device mounted on a camera or the like, and more particularly, to a lens driving device provided with a lens feeding mechanism.

[0002]

2. Description of the Related Art In a compact camera or the like, a conventional lens driving apparatus used for focusing includes a lens barrel (lens holding member) holding a lens, a DC motor for reciprocatingly driving the lens barrel in a feeding direction, A drive mechanism including a gear train, a lead screw, and the like, an encoder for detecting a rotation amount of the drive mechanism, a calculation unit for calculating a feeding amount based on a signal of the encoder, and a start timing when calculation is started by the calculation unit A detection sensor (photo interrupter) for detecting the
It is configured by a control unit and the like that performs various controls.

[0003]

By the way, in the above-mentioned conventional lens driving device, one trigger signal is generated from the detection sensor, and this one trigger signal is transmitted over the entire extension region of the lens. The rotation amount is detected as a starting point, and control is performed so that a desired feeding amount is obtained. On the other hand, in recent cameras,
As the zoom ratio increases, the moving amount (extending amount) of the lens tends to increase. In particular, in a compact camera, after the shutter is released, the distance to the subject is measured (distance measurement), and based on the result of the distance measurement, the lens is moved from a standby position to a predetermined extension position (focusing). Is being done. Therefore, as the amount of movement of the lens increases as the zoom ratio increases,
There is a problem that the time required for the lens extending operation (focusing) becomes long, and the time lag from the release operation to the shutter operation becomes large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to shorten the time required for the lens extending operation while increasing the zoom ratio and the like. An object of the present invention is to provide a lens driving device for a camera.

[0005]

A lens driving device according to the present invention comprises a lens holding member for holding a lens, a driving mechanism for reciprocatingly driving the lens holding member for extending the lens, and an extension operation by the driving mechanism. A lens driving device for a camera, comprising: detecting means for detecting a starting point of the camera; and control means for controlling an operation of a driving mechanism based on an output signal of the detecting means. A plurality of standby positions corresponding to a plurality of shooting modes having different amounts are set, and the detecting unit detects any one of the plurality of standby positions as a starting point of the feeding operation according to the shooting mode. It is characterized by: According to this configuration, when any one of the plurality of standby positions is detected as the starting point by the detection unit, the control unit controls the driving mechanism based on the output signal of the detection unit to move the lens holding member to a predetermined position. Extending position (focusing position)
Move to That is, starting from any one of the plurality of standby positions set in the lens extension area,
An extension operation (focusing) of the lens is performed. As a result, the time required for feeding out is shorter than when the standby position is at one position, and the time lag until the shutter operation is shortened or eliminated by that much.

In the above arrangement, the plurality of photographing modes are:
It is possible to adopt a configuration including a telephoto shooting mode and a wide-angle shooting mode, and a plurality of standby positions including a telephoto-side standby position corresponding to the telephoto shooting mode and a wide-angle-side standby position corresponding to the wide-angle shooting mode. it can. According to this configuration, for example, the shooting mode switch of the camera
When the telephoto shooting mode is selected, the lens is extended (focused) from the telephoto side standby position. On the other hand, when the wide-angle shooting mode is selected, the lens is extended from the wide-angle standby position (focusing). Adjustment) is performed.

In the above arrangement, the control means controls the driving mechanism to move the lens holding member to a standby position corresponding to the photographing mode before the release operation.
A configuration can be employed. According to this configuration, before the release operation of the camera, the lens holding member is located at a position corresponding to the photographing mode (at the telephoto side standby position in the telephoto mode, and at the wide angle side standby position in the wide angle mode). Has been moved in advance, and the lens is extended (focused) from this position. As a result, the time lag caused by the extension operation from the release operation to the shutter operation is reduced or eliminated.

In the above arrangement, there is provided a calculating means for calculating a driving amount of the driving mechanism in order to position the lens holding member at a desired extension position, and the control means uses the output signal of the detecting means as a starting point. It is possible to adopt a configuration in which the drive mechanism is operated according to the drive amount calculated by the means. According to this configuration, when the detection unit detects any of the standby positions, the calculation unit calculates the drive amount of the drive mechanism from this point on, and the control unit operates the drive mechanism based on the calculation result, and the predetermined amount is determined. Position the lens at the extended position.

In the above structure, the detecting means is coupled to the lens holding member and has a detecting plate having two edges in the extending direction, a light emitting unit and a light receiving unit formed so as to sandwich the detecting plate therebetween. And an optical sensor comprising two edge portions, one of which is associated with the wide-angle standby position and the other is associated with the telephoto standby position. it can. According to this configuration, a position where one edge of the detection plate opens and closes the optical path of the optical sensor is a wide-angle standby position, and a position where the other edge of the detection plate opens and closes the optical path of the optical sensor. Is the telephoto side standby position.

In the above configuration, the driving mechanism has at least a DC motor capable of rotating forward and reverse, and a gear train transmitting the rotational force of the DC motor.
A rotation amount detecting means for detecting the rotation amount is provided, and the calculating means may calculate the extension amount of the lens holding member based on an output signal of the rotation amount detecting means. According to this configuration, the rotation amount detecting means is D
The amount of rotation of the C motor is detected as the amount of rotation of the gear train, the calculating means calculates the amount of extension of the lens holding member based on the detected amount of rotation, and the control means controls the driving mechanism based on the result of the calculation. Activate to position the lens holding member at a predetermined extended position.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 9
FIG. 1 shows an embodiment of a lens driving device according to the present invention, FIG. 1 to FIG. 4 are schematic diagrams, FIG. 5 to FIG. 7 are conceptual diagrams for explaining the operation, and FIG. It is a flowchart explaining.

As shown in FIGS. 1 to 4, a lens driving device according to this embodiment includes a base plate 10 and a holding plate 20.
A lens holding member 40 for holding the lens 30, a driving mechanism 50 for driving the lens holding member 40 to reciprocate in a predetermined direction (extending direction) with respect to the base plate 10, and guiding the lens holding member 40 in a predetermined direction. A guide shaft 60 for performing rotation, a detent shaft 70 for detent of the lens holding member 40,
A coil spring 80 that moves the lens holding member 40 back; a detection unit 90 that detects the position of the lens holding member 40; a rotation amount detection unit 100 that detects the rotation amount (drive amount) of the drive mechanism 50; A control system for performing control is provided as its basic configuration.

The base plate 10 and the holding plate 20 have a substantially disc shape, and as shown in FIG.
0a and 20a are formed. As shown in FIG. 3, a guide shaft 60 and a detent shaft 70 are implanted on the main plate 10 in parallel with the extension direction of the lens 30.
Motor 51, pinion 52, two-stage gear 5
3, a gear 54, a two-stage gear 55, a lead screw 56 with a gear 56a, and the like. Further, on the opposite side of the pinion 52, a rotation detection plate 102 with a gear 101 and a gear 102a is provided. The pinion 52, the two-stage gear 53, the gear 54, the two-stage gear 55, the gear 56a, the gear 101, and the gear 102a mesh with each other to form a gear train that transmits the rotation of the DC motor 51, It is rotatably supported between the base plate 10 and the cover plate 15.

As shown in FIG. 1, the rotation detecting plate 102 includes a plurality of blades 102b extending radially, and a photo interrupter 103 is provided so as to sandwich the plurality of blades 102b. Photo interrupter 103
Is an optical sensor composed of a light emitting unit and a light receiving unit. When the rotation detection plate 102 rotates, the blade 102b opens and closes an optical path (performs light transmission and light blocking) and generates a pulse signal at each predetermined rotation angle. It is supposed to. Note that the rotation detection plate 102 may be provided with a plurality of slits 102b ', as shown in FIG. 2, instead of the plurality of blades 102b. That is, the gear 101, the rotation detection plate 102 with the gear 102a, the photo interrupter 103, etc.
A rotation amount detection unit 100 (also referred to as an encoder) that detects the rotation amount of the DC motor 51 via the gear 101 is configured.

The lens holding member 40 is formed in a substantially cylindrical shape from a resin material, and has a lens 30 held on the inner peripheral surface thereof as shown in FIGS. Also,
As shown in FIGS. 1 to 3, on a part of the outer peripheral surface,
An arm portion 41 extending radially outward, a fitting portion 42,
The restricting portion 43, the detection plate 91 and the like are integrally formed.
A lead screw 56 is screwed into the female screw portion 41a formed at the tip of the arm portion 41. A guide shaft 60 is slidably fitted in the fitting hole of the fitting portion 42 to guide the lens holding member 40 in the extending direction. The rotation preventing shaft 70 is inserted into the long hole of the restricting portion 43 to restrict the rotational movement of the lens holding member 40 in the circumferential direction.

As shown in FIGS. 1 and 4, the detection plate 91 is formed in an inverted L-shape, and has two edges (an upper edge 91a and a lower edge 91a) in the feeding direction. 91
b) is formed. A photo interrupter 92 is provided so as to sandwich the detection plate 91. The photo interrupter 92 is an optical sensor including a light emitting unit and a light receiving unit, and the edge 91 a and the edge 9 of the detection plate 91.
When the optical path 92a is closed (blocked) and opened by 1b, the starting point of the feeding operation is detected, and a detection signal is generated. That is, the detection plate 91 and the photo-interrupter 92 constitute detection means for detecting the starting point of the feeding operation by the drive mechanism 50. The edge 91a corresponds to a wide-angle side standby position to be described later. Reference numeral 91b corresponds to a later-described telephoto-side standby position.

The control system of this apparatus includes a distance measuring device for measuring the distance to the subject, a counter for counting the pulses generated by the rotation amount detecting means 100, a calculating means for performing various calculations, and various control signals. The microcomputer includes a microcomputer (CPU) serving as control means and the like, a storage unit (ROM) in which the relationship between the distance to the subject and the extension position of the lens 30 is stored in advance as a control map.

The operation of the detecting means 90, the rotation amount detecting means 100, and the like will be described. As shown in FIG. 5, the standby position of the lens holding member 40 is a wide-angle side standby position corresponding to the wide-angle photographing mode ( WIDE-side standby position) and telephoto-side standby position (T
(ELE side standby position). At the wide-angle standby position, as shown in FIG.
The edge 91 a of the first optical path 92 is the optical path 92 of the photo interrupter 92.
It is located a predetermined distance below a. Then, the DC motor 51 rotates forward (C) by a predetermined pulse count (control count) detected by the rotation detecting means 100.
When W is applied, the detection plate 91 (lens holding member 40)
From the standby position on the wide angle side shown in FIG. 6A to the switching position (HP1) from light transmission to light shielding for generating a detection signal shown in FIG. 6B.

At this time, the detecting means 90 detects the L level signal (HP ↓), and based on the detected signal (as a starting point), counting of the pulse (rotation amount) issued from the rotation detecting means 100 is started. When the count value based on the distance measurement signal and the control map is reached, the DC motor 51
Is stopped, and the extending operation (focusing) on the wide-angle side is completed. When returning to the wide-angle side standby position, the DC motor 51 is rotated in reverse (CCW energized), and the detection plate 91 (lens holding member 40) reaches the switching position (HP1) from light-shielding to light-transmitting. The means 90 detects the H level signal (HP #), and the DC motor 51 is further rotated backward from this position by the above-mentioned control count, and FIG.
To the wide-angle side standby position shown in FIG.

On the other hand, in the telephoto-side standby position, FIG.
As shown in (a), the edge 91b of the detection plate 91 is located a predetermined distance below the optical path 92a of the photointerrupter 92. When the DC motor 51 is normally rotated (CW energized) by a predetermined pulse count (control count) detected by the rotation detecting means 100, the detection plate 91 (lens holding member 40) is turned on as shown in FIG. 7) from the standby position on the wide-angle side to the switching position (HP2) from light blocking to light transmission for generating the detection signal shown in FIG. 7B.

At this time, the detecting means 90 detects the H level signal (HP #), and based on the detected signal (as a starting point), counting of the pulse (rotation amount) issued from the rotation detecting means 100 is started. When the count value based on the distance measurement signal and the control map is reached, the DC motor 51
Is stopped, and the extension operation (focusing) on the telephoto side is completed. When returning to the telephoto side standby position, the DC motor 51 is rotated in reverse (CCW energized), and the detection plate 91 (lens holding member 40) reaches the switching position (HP2) from light transmission to light shielding, and performs detection. The means 90 detects the L level signal (HP ↓), and from this position, the DC motor 51 is further rotated in the reverse direction by the above-mentioned control count, and FIG.
It reaches the telephoto side standby position shown in FIG.

Next, the control operation when the lens driving device according to the present invention is mounted on a camera will be described with reference to FIGS.
This will be described with reference to the flowchart of FIG. The camera body has a main switch for turning the power on and off,
A release switch for performing a shutter operation, a shooting mode changeover switch capable of selecting one of a wide-angle shooting mode and a telephoto shooting mode in which the amount of extension of the lens 30 is different, and the like are provided.

First, with the main switch of the camera turned off, the lens holding member 40 is stopped with the wide-angle standby position (WIDE-side standby position) as a stop position. When the main switch of the camera is turned on, it is determined whether the shooting mode is the wide-angle shooting mode (WIDE) or the telephoto shooting mode (TELE) (step S).
2). Here, in the case of the wide-angle photographing mode, the flow directly shifts to the release operation (step S3).

On the other hand, in the case of the telephoto shooting mode, the DC motor 51 is normally rotated (CW energized) (step S4), and it is determined whether or not the detecting means 90 has issued the L level signal (HP ↓). It is determined whether or not the edge 91a has blocked the optical path 92a (step S5). When the L level signal is issued, the pulse signal emitted from the rotation amount detecting means 100 (encoder) is counted (starts reading) from this time (step S6) until the pulse reaches the predetermined control count value set in advance. DC motor 51
Is performed. Subsequently, it is determined whether or not the lens holding member 40 has reached the telephoto side standby position (TELE side standby position) (step S7). When the lens holding member 40 is at the telephoto side standby position, the power supply to the DC motor 51 is cut off (step S7). Step S8), the operation proceeds to the release operation (step S3).

After the release operation (step S3), the distance to the subject is measured by the distance measuring device (step S3).
9) A count value for feeding control corresponding to the obtained distance measurement signal is calculated (step S10). Then, when the DC motor 5 is rotated forward (CW energized) and fed out by a predetermined amount, in the case of the wide-angle shooting mode (step S1).
2) The detection means 90 detects the switching position (HP1) from light transmission to light shielding shown in FIG.
(P ↓) is determined (step S).
13). On the other hand, in the case of the telephoto shooting mode (step S1)
In 2), the detection means 90 detects the switching position (HP2) from light blocking to light transmission shown in FIG.
P ↑) is determined (step S).
14).

When the detecting means 90 respectively issues an L level signal (HP ↓) or an H level signal (HP ↑), a pulse (from the rotation detecting means 100) (encoder) generated from the rotation detecting means 100 (encoder) based on this signal (as a starting point). Rotation amount)
Is started (step S15), and the DC motor 51 is normally rotated (CW energized) until a count value calculated in advance based on the distance measurement signal and the control map is reached,
The lens holding member 40 (the lens 3
(0) is moved to perform focusing (step S1).
6) When the focus is achieved, the power is cut off (step S).
17). Thereafter, a shutter operation is performed (step S18), and one photographing operation ends.

After the photographing, the DC motor 51 rotates in the reverse direction (C
CW is supplied (step S19), and in the case of the wide-angle shooting mode (step S20), the detecting means 90 detects the switching position (HP1) from light blocking to light transmission and generates an H level signal (HP #). It is determined whether or not this is the case (step S21). On the other hand, in the case of the telephoto shooting mode (step S
In step 20), it is determined whether the detection means 90 has detected the switching position (HP2) from light transmission to light shielding and has generated an L level signal (HP ↓) (step S22).

Then, when the detecting means 90 issues an H level signal (HP ↑) or an L level signal (HP ↓), respectively, from this point on, D is further increased by a predetermined control count.
The C motor 51 is rotated in reverse (CCW energized) (step S
23) It is determined whether or not the lens holding member 40 has reached each standby position (wide-angle side standby position or telephoto side standby position) (step S24). Is cut off and stopped (step S25).

Thereafter, the main switch of the camera is turned off.
(Step S26), it is determined whether or not the lens holding member 40 is at the wide-angle side standby position (the position shown in FIG. 6A) (step S27). Here, in the case of being at the wide-angle side standby position, that position remains as the rest position. On the other hand, when it is not at the wide-angle side standby position, the DC motor 5
1 is reversed (CCW energization), the process returns to step S21, and a series of operations is performed again (steps 23 to 27). Then, when the lens holding member 40 is located at the wide-angle side standby position, that position remains as the rest position.

As described above, the standby position of the wide angle side and the standby position of the telephoto side corresponding to the photographing mode are set as the positions where the lens holding member 40 stands by, and the photographing mode information determined before the release operation sets In order to move the lens holding member 40 to a standby position corresponding to the shooting mode in advance and wait for standby, the lens holding member 4 after the release is released.
It is possible to shorten the moving amount (extending amount) of 0, and to shorten the control time in a series of sequences.

In the above-described embodiment, the standby positions of the lens holding member 40 are set at two positions, that is, the wide-angle standby position and the telephoto-side standby position. However, the present invention is not limited to this. It is also possible to set a standby position such as a location. Further, in the above embodiment, the DC motor 51 and the gear trains 52 to
Although 56a and the like were used, the invention is not limited to this.
It is also possible to employ an actuator or the like that applies a linear moving force. In this case, an encoder or the like that detects a linear moving amount can be used instead of the rotation amount detecting unit 100. Further, in the above embodiment,
As the detection means 90, a configuration including the detection plate 91 and the photo interrupter 92 is employed, but the invention is not limited to this, and other sensors and the like can be employed.

[0032]

As described above, according to the lens driving device of the present invention, the standby position where the lens (lens holding member) waits before photographing is set in accordance with a plurality of photographing modes in which the amount of extension of the lens is different. By setting the plurality of standby positions, a lens extending operation (focusing) is performed starting from one of the set plurality of standby positions. As a result, the time required for feeding out is shorter than when the standby position is at one position, and the time lag until the shutter operation is eliminated by that amount. In particular,
By moving the lens holding member to the standby position corresponding to the photographing mode before the release operation, the time lag caused by the extension operation from the release operation to the shutter operation is reduced or eliminated.

In setting the standby position, a detection plate constituting a part of the detection means is provided integrally with the lens holding member, and two edges of the detection plate in the extending direction are used for detecting the standby position. By using this, the wide-angle standby position and the telephoto-side standby position can be easily set.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a lens driving device according to the present invention.

FIG. 2 is a plan view showing one embodiment of a lens driving device according to the present invention.

FIG. 3 is a partial cross-sectional view showing one embodiment of a lens driving device according to the present invention.

FIG. 4 is a partial cross-sectional view showing one embodiment of a lens driving device according to the present invention.

FIG. 5 is an operation diagram showing a relationship between a standby position and a feeding operation of the lens driving device according to the present invention.

6A and 6B are diagrams illustrating a relationship between a detection unit forming a part of the lens driving device and a standby position, and FIG. 6A illustrates a state in which a detection plate (lens holding member) is at a wide-angle side standby position. (B) is a diagram showing a state in which the detection plate (lens holding member) is located immediately before blocking the optical path and is in a position for generating a detection signal.

7A and 7B are diagrams illustrating a relationship between a detection unit forming a part of a lens driving device and a standby position, and FIG. 7A illustrates a state in which a detection plate (lens holding member) is at a telephoto side standby position. (B) is a diagram showing a state in which the detection plate (lens holding member) is located immediately before opening the optical path and is in a position for generating a detection signal.

FIG. 8 is a flowchart showing a control operation when the lens driving device according to the present invention is mounted on a camera.

FIG. 9 is a flowchart illustrating a control operation when the lens driving device according to the present invention is mounted on a camera.

[Explanation of symbols]

Reference Signs List 10 base plate 15 cover plate 20 holding plate 30 lens 40 lens holding member 41 arm portion, 42 fitting portion, 43 restricting portion 50 driving mechanism 51 DC motor, 52 pinion 54, 56a, 101, 102a Gears (gear train) 53, 55 Two-stage gear (gear train) 56 Lead screw 60 Guide shaft 70 Detent shaft 80 Coil spring 90 Detecting means 91 Detecting plate, 91a One edge, 91b The other edge 92 Photo interrupter (optical sensor), 92a Optical path Reference Signs List 100 rotation amount detection means (encoder) 102 rotation detection plate, 102b plural blades, 102b
´ Multiple slits 103 Photo interrupter (optical sensor)

Claims (6)

[Claims] 1. A lens holding member for holding a lens, a driving mechanism for driving the lens holding member to reciprocate so as to extend the lens, a detecting means for detecting a starting point of a feeding operation by the driving mechanism, and the detection Control means for controlling the operation of the drive mechanism based on an output signal of the means,
A plurality of standby positions corresponding to a plurality of photographing modes in which the amount of lens extension is different in the lens holding member, wherein the detecting means comprises: According to the, any of the plurality of standby positions is detected as the starting point,
A lens driving device characterized by the above-mentioned. 2. The plurality of shooting modes include a telephoto shooting mode and a wide-angle shooting mode, and the plurality of standby positions correspond to a telephoto-side standby position corresponding to the telephoto shooting mode and the wide-angle shooting mode. 2. The lens driving device according to claim 1, further comprising a wide-angle side standby position. 3. The control means according to claim 1, further comprising:
The lens driving device according to claim 1, wherein the driving mechanism controls the driving mechanism to move the lens holding member to a standby position corresponding to the shooting mode in advance. 4. An arithmetic unit for calculating a driving amount of the driving mechanism so as to position the lens holding member at a desired extension position, wherein the control unit performs the arithmetic operation using an output signal of the detecting unit as a starting point. 4. The lens driving device according to claim 1, wherein the driving mechanism is operated according to the driving amount calculated by the means. 5. The detecting means includes: a detecting plate coupled to the lens holding member and having two edges in a feeding direction; and a light emitting unit and a light receiving unit formed to sandwich the detecting plate therebetween. An optical sensor, wherein one of the two edge portions is associated with the wide-angle standby position, and the other is associated with the telephoto-side standby position. The lens driving device according to claim 2. 6. The driving mechanism has at least a DC motor capable of rotating forward and reverse, and a gear train for transmitting a rotational force of the DC motor, and a part of the gear train detects a rotation amount thereof. 6. The lens according to claim 4, further comprising: a rotation amount detecting unit configured to calculate an extension amount of the lens holding member based on an output signal of the rotation amount detecting unit. 7. Drive.