JP2003139570A - Position detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the movement amount of a moving object correctly detectable with a relatively simple structure. SOLUTION: A region irradiated with output light from a floodlight part 425 through a transmission part of a scale member 44 and a region not irradiated with the output light from the floodlight part 425 due to a shade part of the scale part 44 are formed along the installation direction of light receiving element of a light receiving part 427, and the movement amount of a taking lens LN is detected by using the movement of a signal waveform generated in the receiving part 427 accompanying the movement of the scale member 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device which is built in an electric device such as a camera and detects a moving amount of a moving object such as a photographing lens.

[0002]

2. Description of the Related Art Recently, an engaging member to which a moving object such as a photographing lens is attached is coupled to a rod-shaped driving member so as to have a predetermined frictional force, and one end of the driving member is electrically connected to a piezoelectric element or the like. An impact type actuator has been developed, which is fixed to a mechanical conversion element (Japanese Patent Laid-Open No. 200-200200).
1-211669, etc.). Such an impact type actuator changes the moving direction of the engaging member by applying a drive voltage composed of, for example, a rectangular wave to the electromechanical conversion element and setting the duty ratio of the drive voltage to a predetermined value. Is possible. The impact type actuator configured as described above is superior to the conventional stepping motor that moves a moving object such as a photographing lens in terms of high speed and high quietness.

[0003]

By the way, in the conventional stepping motor, it is possible to detect the moving amount of the moving object such as the photographing lens by counting the number of pulses of the driving voltage supplied to the exciting coil. In Although,
The impact type actuator as described above cannot detect the moving amount of the moving object such as the photographing lens attached to the engaging member by itself. Therefore, when it is necessary to detect the moving amount, the position detecting device is separately provided. Will have to be added.

As such a position detecting device, the magnet N
A long scale member in which poles and S poles are alternately arranged, and movement of the scale member is detected by a magnetic sensor, and the movement amount of the scale member is determined based on a signal waveform generated by the magnetic sensor. It is conceivable to use the one that is detected. However, in such a position detecting device,
In order to increase the resolution of position detection, it is necessary to detect the signal level at a predetermined phase of the signal waveform, which complicates the circuit configuration for the detection, and adds the scale member and the magnetic sensor. If the relative position of and shifts, it becomes impossible to detect the exact amount of movement,
There is a problem that severe mounting position accuracy of both is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a position detecting device capable of accurately detecting the moving amount of a moving object with a relatively simple structure.

[0006]

In order to achieve the above object, the invention of claim 1 is a position detecting device for detecting the amount of movement of a moving object, which is a light projecting unit for radiating output light in a predetermined direction. And a light-receiving section in which a plurality of light-receiving elements for receiving the output light from the light-projecting section are arranged in a predetermined direction, and a light-guide section for guiding the output light from the light-projecting section to the light-receiving section. And non-light-guiding portions that are not guided are alternately arranged, and are interlocked with the moving object, and the light-guiding portion and the non-light-guiding portion are relative to the light-projecting portion and the light-receiving portion. A scale member that is movably disposed, an area where the light guide section of the scale member irradiates the output light from the light projecting section, and a non-light guide section of the scale member that outputs from the light projecting section. The area not irradiated with light is along the direction in which the light-receiving element of the light-receiving section is arranged. And a movement amount detecting means for detecting the movement amount of the moving object by utilizing the fact that the signal waveform generated in the light receiving unit moves with the relative movement of the scale member. It has a feature.

According to this structure, the scale member moves relative to the light projecting portion and the light receiving portion, so that the light receiving portion has a region where the light output from the light emitting unit is irradiated and a region where it is not irradiated. The signal waveform having a predetermined shape is generated in the light receiving part by being formed along the arrangement direction of. Since this signal waveform moves with the relative movement of the scale member, the movement amount of the moving object is detected by using the movement of this signal waveform. In this case, by detecting the position of the singular point of the signal waveform generated in the light receiving section before the movement of the scale member is started, the positional relationship between the scale member and the light projecting section and the light receiving section is accurately set. Even if there is no moving object, the moving amount of the moving object is accurately detected.

The area where the output light from the light projecting portion is not irradiated is not limited to the case where the output light is not irradiated at all, and the area where the output light from the light projecting portion is irradiated is smaller than the area irradiated with the output light. It also includes the case where it is done. Further, the scale member is interlocked with the moving object, and the light guide section and the non-light guide section are arranged to be movable relative to the light projecting section and the light receiving section, which means that the scale member can move together with the moving object. Not only when the scale member is moved with respect to the light emitting unit and the light receiving unit whose position is fixed, but also the scale member in which the light emitting unit and the light receiving unit that are movable together with the moving object are positionally fixed. It also includes the case of moving to.

According to a second aspect of the present invention, in the first aspect, the movement amount detecting means has a first movement amount that exceeds the arrangement pitch of the light guide portions and the non-light guide portions of the scale member. , The second moving amount within the array pitch is added to detect the moving amount of the moving object, and the first moving amount is repeatedly generated in the light receiving unit by relative movement of the scale member. The number of times the singular point of the signal waveform passes through the light receiving element at a position corresponding to the singular point of the signal waveform before the relative movement of the scale member, and the arrangement pitch of the light guide section and the non-light guide section of the scale member. And the second movement amount is obtained after the relative movement of the light receiving element and the scale member at the position corresponding to the singular point of the signal waveform before the relative movement of the scale member is started. Signal waveform singular Between the light receiving elements at the positions corresponding to the singular points within the arrangement pitch of the light guide portion and the non-light guide portion of the scale member from the light receiving element at the position corresponding to the singular point of the signal waveform before the relative movement is started. It is obtained based on the product of the number of the light receiving elements existing in 1 and the array pitch of the light receiving elements.

According to this structure, the number of times the singular point of the signal waveform repeatedly generated by the relative movement of the scale member passes through the light receiving element at the position corresponding to the singular point of the signal waveform before the relative movement of the scale member is started, and , The first movement amount of the moving object is obtained based on the product of the arrangement pitch of the light guide portion and the non-light guide portion of the scale member. Further, the light receiving element at the position corresponding to the singular point of the signal waveform before the relative movement of the scale member and the singular point of the signal waveform after the relative movement of the scale member are stopped are the singular points of the signal waveform before the relative movement is started. Of the number of light receiving elements existing between the light receiving elements at the positions corresponding to the singular points in the array pitch of the light guide section and the non-light guide section of the scale member from the light receiving elements at the corresponding positions, and the arrangement pitch of the light receiving elements The second movement amount of the moving object is obtained based on the product. Then, the accurate movement amount of the moving object is detected by adding up the first movement amount and the second movement amount.

That is, the position of the singular point of the signal waveform generated in the light receiving unit is detected before the relative movement of the scale member is started, so that the positional relationship between the scale member and the light projecting unit and the light receiving unit is detected. It is possible to accurately detect the moving amount of the moving object even when the moving object is not accurately set at the time of assembling.

According to a third aspect of the present invention, in the first or second aspect, the light projecting portion and the light receiving portion are arranged to face each other, and the scale member is the light guiding portion. And a non-light-guiding section repeatedly arranged in a linear direction at a predetermined pitch, and the light-projecting section such that the light-guiding section and the non-light-guiding section are aligned with the light-receiving element. It is characterized in that it is arranged so as to be relatively movable between the light receiving part and the light receiving part.

According to this structure, the scale member is relatively moved in a straight line direction between the light projecting portion and the light receiving portion which are arranged to face each other, and the output light from the light projecting portion is guided by the light guide portion of the scale member. As a result of irradiating the light receiving unit by passing through, the moving amount of the moving object moving in the linear direction is detected.

According to a fourth aspect of the present invention, in the third aspect, the light-receiving portion has its light-receiving elements arranged at a finer pitch than the arrangement pitch of the light-guiding portion and the non-light-guiding portion of the scale member. It is characterized by having at least one pitch length dimension of the light guide portion and the non-light guide portion. According to this configuration, a predetermined signal waveform is formed in the light receiving section by the relative movement of the scale member,
It becomes possible to detect the exact amount of movement of the moving object.

The invention of claim 5 is the same as claim 1 or 2.
The light emitting unit and the light receiving unit are arranged side by side along the arrangement direction of the light receiving elements of the light receiving unit, and the scale member includes the light guide unit and the non-light guide unit. Are repeatedly arrayed in a linear direction at a predetermined pitch, and the light projecting section and the light receiving section are arranged so that the array direction of the light guide section and the non-light guide section and the array direction of the light receiving element match. It is characterized in that it is arranged so as to be able to move relative to each other.

According to this structure, the scale member is relatively moved in the linear direction so as to face the light projecting portion and the light receiving portion arranged side by side, and the output light from the light projecting portion is guided by the light guiding portion of the scale member. As a result of being reflected and irradiated to the light receiving unit, the amount of movement of the moving object that moves in the linear direction is detected.

[0017] According to a sixth aspect of the present invention, in the fifth aspect, the light-receiving section arranges the light-receiving elements at a pitch smaller than the arrangement pitch of the light guide section and the non-light guide section of the scale member. And has a length dimension at least twice the arrangement pitch of the light guide portions and the non-light guide portions. According to this configuration, a predetermined signal waveform is formed in the light receiving section by the relative movement of the scale member, and the accurate movement amount of the moving object can be detected.

Further, the invention of claim 7 relates to claims 1 to 6.
In any one of the above, a visible light cut filter is disposed on the light output surface of the light projecting portion. According to this configuration, the visible light included in the output light from the light projecting unit is removed by the visible light cut filter, and the adverse effect of the visible light is prevented.

Further, the invention of claim 8 is the invention of claims 1 to 7.
In any one of the above items, the moving amount detecting means is built in a digital camera equipped with an image sensor, and the movement amount detecting means is configured by an operation control unit for controlling an operation of the digital camera. There is. With this configuration, the position detection device is controlled by the operation control unit that controls the operation of the digital camera. Therefore, the entire structure is simplified and the cost can be reduced.

[0020] According to a ninth aspect of the present invention, in the eighth aspect, the light projecting section outputs the irradiation light while the image pickup signal accumulated in the image pickup device is transferred to the outside of the image pickup device. It is characterized in that it is controlled to According to this configuration, even when visible light is included in the output light from the light projecting unit, the image sensor of the digital camera is prevented from being adversely affected by visible light.

The tenth aspect of the present invention is the first or second aspect.
In the one according to, the scale member has a disc shape in which the light guide portion and the non-light guide portion are repeatedly arranged in a circumferential direction at a predetermined pitch, and the scale member is provided with respect to the light emitter and the light receiver. It is characterized in that the light guide section and the non-light guide section are relatively movable with respect to the light projecting section and the light receiving section by rotating relative to each other.

According to this structure, the light guide section and the non-light guide section are moved relative to the light projecting section and the light receiving section as in the case where the scale member is formed in a linear shape, so that the light receiving section is formed. A region where the output light from the light projecting unit is irradiated and a region where the output light is not irradiated are formed along the arrangement direction of the light receiving element, so that the moving amount in the circumferential direction of the moving object that rotates can be accurately detected. It

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram schematically showing the structure of an impact type actuator to which a position detecting device according to an embodiment of the present invention is applied. In this figure, the impact type actuator 10 includes a drive unit 12
And a drive circuit unit 14 for driving the drive unit 12, and the drive unit 1.
2, the engaging member 3 that moves along a driving member 28 described later.
Position detection unit (movement amount detection unit) 16 that detects a movement amount of 0
And a base end sensor 18 disposed at the base end position of the drive unit 12.
And a tip sensor 20 disposed at the tip position of the drive unit 12.
And a control unit 22 that controls the overall operation.

FIG. 2 is a perspective view showing a structural example of the drive unit 12. In this figure, the drive unit 12 has a fixed element structure, and includes a support member 24 and an electromechanical conversion element 2.
6, the driving member 28 and the engaging member 30.

The supporting member 24 holds the electromechanical conversion element 26 and the driving member 28, and by hollowing out the inside thereof, leaving both axial end portions 241 and 242 of the cylindrical body and the partition wall 243 at the substantially center. It has the 1st accommodation space 244 and the 2nd accommodation space 245 which were formed. Also,
The circular hole 2 is provided at the center position of the other end 242 of the support member 24.
46 is provided, and a circular hole 247 is provided at the center position of the partition wall 243.

The electromechanical conversion element 26 is constituted by laminating a plurality of piezoelectric substrates having a predetermined thickness, for example, with electrodes (not shown) interposed between the piezoelectric substrates, and is an opposite electrode on the outer surface. A positive electrode (one electrode) 261 and a negative electrode (other electrode) 262 are provided. The electromechanical conversion element 26 is housed in the first housing space 244 in a state in which the direction of expansion and contraction, which is the direction between the opposing electrodes, matches the axial direction of the support member 24, and one end face (for example, the positive electrode 2
61 side) is fixed to the end surface of the first accommodation space 244 on the one end 241 side.

The drive member 28 is formed in a rod shape having a round cross section, and both ends thereof are the other end 2 of the support member 24.
The circular hole 246 of 42 and the circular hole 247 of the partition wall 243 are accommodated in the second accommodating space 245 so as to be movable along the axial direction. In addition, the end of the drive member 28 protruding into the first housing space 244 is fixed to the other end surface of the electromechanical conversion element 26 (for example, the negative electrode 262 side), and the other end 242 of the support member 24. The end portion protruding to the outside of is pressed by the leaf spring 32 with a predetermined spring pressure,
The electromechanical conversion element 26 is biased. The reason why the drive member 28 is biased by the leaf spring 32 in this way is to stabilize the axial displacement of the drive member 28 due to the expansion / contraction operation of the electromechanical conversion element 26.

The engaging member 30 includes a base portion 302 having mounting portions 301, 301 on both axial sides of the driving member 28, and a sandwiching member 30 mounted between the mounting portions 301, 301.
3 and the base 302 has a second accommodation space 245.
While being loosely fitted to the drive member 28 inside, the sandwiching member 303 is pressed by the leaf spring 304 to come into contact with the peripheral surface of the drive member 28, whereby the engagement member 30 is attached to the drive member 28 with a predetermined frictional force. Are combined. As a result, the engagement member 30 can move along the axial direction of the drive member 28 when a driving force larger than the frictional force acts on the engagement member 30. It should be noted that the taking lens LN (FIG. 1), which is a moving object, is attached to the engaging member 30.

FIG. 3 is a diagram showing a configuration example of the drive circuit section 14. In this figure, the drive circuit unit 14 is the control unit 2
A drive voltage consisting of a rectangular wave is continuously output based on the control signal from 2 and the drive voltage is applied to the electromechanical conversion element 26 so that the displacement waveform when the electromechanical conversion element 26 expands and contracts has a sawtooth shape. The waveform generator 36 is composed of a digital circuit and the power amplifier 38. The waveform generator 36 is, for example, 0 to
A drive voltage having a rectangular wave of 5 V is generated and supplied to the power amplifier 38. The power amplifier 38 amplifies the drive voltage supplied from the waveform generator 36 to a drive voltage having a rectangular wave of 0 to 10 V, for example. It is applied to the electromechanical conversion element 26.

FIG. 4 is a diagram showing a correspondence relationship between the pulse waveform of the drive voltage output from the drive circuit section 14 applied to the electromechanical conversion element 26 and the displacement due to expansion and contraction of the electromechanical conversion element 26. Here, the drive voltage shown in FIG. 4A is the electromechanical conversion element 2 when the drive frequency fd of the drive voltage is such that the support member 24 and the drive member 28 are fixed.
6 is set to be 0.7 times the resonance frequency fr (for example, 50 kHz) (fd = 0.7 × fr), and the duty ratio D (D = B / A) is set to 0.3. It was done.

When the drive voltage shown in FIG. 4A is applied to the electromechanical conversion element 26, the electromechanical conversion element 2
The displacement waveform of 6 has a sawtooth shape having a slow rising portion C (the electromechanical conversion element 26 extends gently) and a steep falling portion D (the electromechanical conversion element 26 rapidly shrinks), and the engaging member 30 Moves along the drive member 28 in the arrow a1 direction (FIG. 1), which is the feeding direction (the direction away from the electromechanical conversion element 26). The engaging member 30 is
The drive frequency fd of the drive voltage is, for example, 0.3 × fr and 1.5.
Xfr and the duty ratio D is, for example, 0.1.
When it is within the range of 05 to 0.45, it can move in the direction of arrow a1 (FIG. 1).

The drive voltage shown in FIG. 4 (b) has the drive frequency fd of the drive frequency fd of the electromechanical conversion element 26 in a state where the support member 24 and the drive member 28 are fixed (for example, 0.7 times of 50 kHz (fd =
0.7 × fr) and the duty ratio D
(D = B / A) is set to 0.7.

When the drive voltage shown in FIG. 4B is applied to the electromechanical conversion element 26, the electromechanical conversion element 2
The displacement waveform of 6 has a sawtooth shape having a steep rising portion C (the electromechanical conversion element 26 expands rapidly) and a gradual falling portion D (the electromechanical conversion element 26 gradually contracts), and the engaging member 30 Moves in the direction of arrow a2 (FIG. 1), which is the return direction (direction approaching the electromechanical conversion element 26) along the drive member 28. The engaging member 30 has a driving frequency fd of a driving voltage of, for example, 0.3 × fr and 1.5 × fr.
When the duty ratio D is within the range of 0.55 to 0.95, for example, it can move in the direction of the arrow a2 (FIG. 1).

FIG. 5 is an exploded perspective view showing a structural example of the mechanical portion of the position detecting portion 16 according to the first embodiment. In this figure, the position detector 16 includes a light detector 42 and a scale member 44. The photodetecting section 42 has a U-shaped side view including an upper wall section 421, a lower wall section 422 facing the upper wall section 421 at a predetermined distance, and a standing wall section 423 connecting the both at an edge. Support member 424 made of an insulating material such as synthetic resin, and a light emitting element such as an LED (Light Emitting Diode) arranged on the lower surface side of the upper wall portion 421. Output light from this light emitting element is directed downward. And a light projecting section 425 for irradiating
Visible light cut filter 426 disposed on the light output surface of No. 5
And a CCD (Charge-Coupl) arranged on the upper surface side of the lower wall portion 422 and receiving output light (irradiation light) from the light projecting portion 425.
ed Device) and a light receiving unit 427 which is a line sensor including a solid-state image sensor.

Here, the support member 424 has an upper wall portion 421.
Between the lower wall portion 422 and the lower wall portion 422, the movement path 42 of the scale member 44 in the linear direction (direction indicated by arrow X) along the surface of the standing wall portion 423.
8 is configured. The light projecting section 425 is configured to output diffused light having a width of, for example, about 0.1 to 0.3 mm. In addition, the light receiving unit 427
Is a plurality (for example, at least 40) of the light receiving elements 42.
9 are arranged in a line along the linear direction at a predetermined arrangement pitch (for example, 0.005 mm), and the arrangement direction of the light receiving elements 429 and the moving direction of the scale member 44 in the moving path 428 ( It is arranged on the lower wall portion 422 so as to substantially coincide with the direction indicated by the arrow X).

The scale member 44 has one end fixed to the engagement member 30 (FIGS. 1 and 2) so that the scale member 44 can move together with the engagement member 30. Four
A linear (for example, 0.1 mm wide) transmissive part (light guide part) that allows the output light (irradiation light) from the light projecting part 425 to pass through and be guided to the light receiving part 427 along the longitudinal direction of 41. 44
2 and the light receiving section 42 by blocking the output light from the light projecting section 425.
Line shape that does not lead to 7 (for example, 0.1 mm width)
Light-shielding portions (non-light-guiding portions) 443 are alternately and repeatedly formed, and the light-detecting portion is arranged so that the arrangement direction of the transmitting portion 442 and the light-shielding portion 443 and the light-receiving element 429 of the light-receiving portion 427 are substantially aligned. It is arranged so as to be movable on the movement path 428 of 42.

That is, the scale member 44 has a set of a transparent portion 442 and a light shielding portion 443 which are repeatedly arranged in a linear direction at a predetermined arrangement pitch (for example, 0.2 mm). For example, a transparent synthetic resin. A plurality of linear (for example, 0.1 mm width) light-shielding film bodies of black or the like, which are light-shielding portions, are formed at predetermined intervals (for example, by a film body forming means such as printing or plating on a long substrate 441 made of, for example, It is obtained by continuously forming at 0.1 mm intervals). According to this configuration, the region where the light shielding film body is not formed is the transmissive portion 44.
2, the area where the light shielding film body is formed becomes the light shielding portion 443.

FIG. 6 is a diagram for explaining the principle of detection of the amount of movement of a moving object by the position detecting unit 16. FIG. 6A shows the first scale just before the scale member 44 constituting the position detecting unit 16 starts moving. FIG. 6B shows a state when the scale member 44 is in the position, and FIG. 6B shows an arrangement pitch (for example, 0.2 mm) of the set of the transmission part 442 and the light shielding part 443 from the first position, that is, the width of the transmission part 442. After moving a small distance within the range of the width dimension (for example, 0.2 mm) obtained by adding the dimension (for example, 0.1 mm) and the width dimension (for example, 0.1 mm) of the light shielding portion 443 to the right in the figure. The state at the position of 2 is shown.

Now, when the scale member 44 is in the first position shown in FIG. 6A, the light shielding portion 443 of the scale member 44 is located on the optical axis LS of the light projecting portion 425 (however, It is not limited to the case where the light blocking portion 443 is located on the optical axis LS.). Therefore, the output light from the light projecting unit 425 exists within a predetermined width W1 (a width corresponding to a shaded portion between the scale member 44 and the light receiving unit 427) facing the light shielding unit 443 located on the optical axis LS. Multiple light-receiving elements 4
The plurality of light receiving elements 429 existing in the predetermined widths W2, W3, and W4 on both sides of 29 are respectively irradiated by passing through the transmitting portion 442, but the predetermined width W1 facing the light shielding portion 443 on the optical axis LS. The plurality of light receiving elements 429 present therein are shielded by the light shielding portion 443 and are not irradiated.

Further, among the light receiving elements 429 irradiated with the output light from the light projecting section 425, the plurality of light receiving elements 429 existing within the width W2 are irradiated with the maximum light amount, but the width W3.
(Width corresponding to the shaded portion between the scale member 44 and the light receiving portion 427) and width W4 (scale member 44 and the light receiving portion 427)
A plurality of light-receiving elements 429 existing within the width (corresponding to the shaded portion) are gradually reduced in the amount of light irradiated as they are separated from the position of the width W2.

Therefore, the signal waveform photoelectrically converted and output from the light receiving section 427 (the signal waveform formed according to the signal level generated in each light receiving element 429) has a trapezoidal shape as shown in the figure. Becomes One cycle of this signal waveform corresponds to the arrangement pitch (for example, 0.2 mm) of the pair of the transmission portion 442 and the light shielding portion 443 of the scale member 44 (for example, the scale member 44 and the light receiving portion 42).
Assuming that the distance between 7 is substantially zero, one period of the signal waveform is 0.2 mm. ). Note that this signal waveform approaches a rectangular shape because the width W3 and the width W4 become narrower as the distance between the scale member 44 and the light receiving unit 427 becomes shorter.

Then, when the scale member 44 in the first position shown in FIG. 6A moves to the second position shown in FIG. 6B, the positions of the transmission part 442 and the light shielding part 443 are moved to the right. Since it moves, the light projecting unit 425 in the light receiving unit 427
The area irradiated with the output light from and the area shielded from the light both move to the right. Therefore, the light receiving unit 427
The signal waveform output from will also move to the right as shown. In this example, the signal waveform has a shape in which the tip end side in the moving direction of the trapezoidal portion on the right side shown in FIG. 6A is cut off due to the number of light receiving elements 429 arranged in the light receiving portion 427.

Here, the horizontal axis (time axis) of the signal waveform is the x axis, the position of the optical axis LS is the reference point (zero), and the scale member 44 is at the first position in FIG. 6A. When the coordinate value of a point (point at which the position of the waveform can be specified) of the signal waveform at this time, for example, point a (starting point of rising of the trapezoidal portion on the right side) is x1, the scale member 4
When point 4 moves to the second position in FIG. 6B, point a moves to the right, and the coordinate value of point a at that time is x2.

Therefore, the number of light receiving elements 429 between the coordinate values x1 and x2 is counted, and the count value (N of the light receiving elements 429 is set to the arrangement pitch (Ps) of the light receiving elements 429).
It is possible to obtain the amount of movement of the scale member 44 by multiplying the multiplication result value by a correction value (C) corresponding to the distance between the scale member 44 and the light receiving unit 427. That is, the moving amount Ms of the scale member 44 can be obtained by the equation Ms = Ps × Ns × C. The correction value (C) becomes "1" when the distance between the scale member 44 and the light receiving section 427 is substantially zero, and becomes "1" as the distance increases.
Will be a smaller value. Therefore, this correction value (C) may be calculated in advance or experimentally obtained.

For example, the arrangement pitch of the light receiving elements 429 (P
s) is 0.005 mm, the scale member 44 and the light receiving unit 4
The number of light receiving elements 429 between the coordinate values x1 and x2 (Ns), assuming that the distance between the light emitting elements 27 and 27 is substantially zero.
Is 10, the arrangement pitch (Ps) of the light receiving elements 429
Multiplied by the number of light-receiving elements 429 (Ns) to obtain 0.005
mm × 10 pieces × 1 = 0.05 mm is the movement amount of the scale member 44. Since the scale member 44 moves together with the photographing lens LN which is a moving object, the calculated movement amount of the scale member 44 is the photographing lens LN which is a moving object.
Is the amount of movement. In addition, the + area on the right side of the reference point of the x-axis is defined as the direction in which the engaging member 30 moves in the feeding direction, and x
By setting the-region on the left side of the reference point of the axis as the direction in which the engaging member 30 moves in the return direction, the moving direction can be obtained at the same time as the moving amount of the taking lens LN.

As described above, in the present invention, the detection of the movement amount within the range of the arrangement pitch (for example, 0.2 mm) of the pair of the transmitting portion 442 and the light shielding portion 443 is "fine position detection".
That is, it is possible to obtain a fine resolution up to the arrangement pitch (for example, 0.005 mm) of the light receiving elements 429 in the light receiving section 427. In addition, in order to enable this “fine position detection”, the light receiving unit 427 corresponds to the arrangement pitch of at least one set of the transmission unit 442 and the light shielding unit 443 (for example, 0.
2 mm length) is required. That is, assuming that the arrangement pitch of the light receiving elements 429 in the light receiving section 427 is, for example, 0.005 mm, at least 40 light receiving elements (when the distance between the scale member 44 and the light receiving section 427 is substantially zero). 429 need to be arranged.

On the other hand, a pair of transmission part 442 and light blocking part 44
The detection of the movement amount exceeding the arrangement pitch of 3 (for example, 0.2 mm) is referred to as "coarse position detection" in the present invention, and this "coarse position detection" can be executed as follows.
That is, a which is a singular point of the signal waveform shown in FIG.
The signal level output from the light receiving element 429 corresponding to the position of the coordinate value x1 of the point changes to (a shape similar to the trapezoidal shape of FIG. 6) as shown in FIG. 7 as the scale member 44 moves. To do.

Now, the signal level of the light receiving element 429 at the coordinate value x1 of the point a of the signal waveform shown in FIG. 6A is "0".
However, when the scale member 44 moves, for example, to the right in the figure, the signal level rises, but at the time when the pair of the transmission unit 442 and the light shielding unit 443 has finished moving (that is, the scale member 44 has one pitch (for example, 1 pitch)). , 0.2 mm) when the movement is completed), the signal level of the light receiving element 429 at the coordinate value x1 returns to “0” again. Further, when the scale member 44 moves to the right in the figure, the signal level rises again, but at the time when the pair of the transmission unit 442 and the light shielding unit 443 has finished moving (that is, the scale member 44 has two pitches (for example, 0 pitch). .4 mm), the signal level of the light receiving element 429 at the coordinate value x1 returns to "0" three times.

Therefore, the number of times that the signal level of the light receiving element 429 at the position of this coordinate value x1 becomes "0" after the start of the movement of the scale member 44 is counted, and the set of the transmitting portion 4 is set.
The movement amount of the scale member 44 can be obtained by multiplying the arrangement pitch (Pc) of the light blocking sections 423 and the number of times the signal level becomes “0” (Nc). That is, the moving amount Mc of the scale member 44 is Mc = Pc
It can be obtained by the formula of × Nc.

For example, a pair of the transmission part 442 and the light blocking part 4
When the arrangement pitch (Pc) of 43 is 0.2 mm and the number of times the signal level becomes “0” (Nc) is 3, a signal is output to the arrangement pitch (Pc) of the pair of the transmission part 442 and the light shielding part 443. Multiply by the number of times the level has reached "0" (Nc).
The movement amount of the scale member 44 is 2 mm × 3 = 0.6 mm. Since the scale member 44 moves together with the taking lens LN which is a moving object, the obtained moving amount of the scale member 44 is the moving amount of the taking lens LN which is a moving object. It should be noted that the case of moving to the right side of the x-axis is defined as +, and the case of moving to the left of the x-axis is defined as −, and the direction of movement of the engaging member 30 in the returning direction is defined as +. As a result, the moving direction can be obtained at the same time as the moving amount of the photographing lens LN.

As described above, the "fine position detection", which is the detection of the movement amount within the range of the arrangement pitch (for example, 0.2 mm) of the pair of transparent portions 442 and the light shielding portions 443, and the pair of transparent portions 442. And the "coarse position detection", which is the detection of the movement amount exceeding the arrangement pitch (for example, 0.2 mm) of the light shielding portion 443, are performed at the same time, and the two types of movement amounts Ms
By adding (adding) the moving amount Mc and the moving amount Mc, an accurate moving amount of the taking lens LN can be obtained.

FIG. 8 is a block diagram showing the control configuration of the position detector 16. In this figure, the position detector 16
Is a light emitting element drive unit 431 for lighting and driving the light projecting unit 425 in addition to the mechanism unit of the light detection unit 42 and the scale member 44.
And a light-receiving element drive unit 4 that performs transfer processing of charges generated by photoelectric conversion in each light-receiving element 429 of the light-receiving unit 427.
32, and an A / D conversion unit 433 that converts an analog signal generated by photoelectric conversion in the light receiving unit 427 into a digital signal.
It has and.

The light emitting element drive section 431, the light receiving element drive section 432 and the A / D conversion section 433 are connected to the control section 22 through an interface circuit (not shown),
The light emitting unit 425 and the light receiving unit 427 are driven at a predetermined timing by the control signal output from the control unit 22, while the movement amount of the photographing lens LN based on the signal waveform generated by the light receiving unit 427 in the control unit 22 is set. Calculation is performed.

Here, the control unit 22 is a CPU (Central Processing Unit) for executing arithmetic processing, and a ROM (Read-Only Memory) for storing control programs and various data.
And a RAM (Random Access) for temporarily storing data
Memory).

Further, the control section 22 includes a light receiving section 427.
The number of times the singular point of the signal waveform generated by the coordinate value detection unit 221 and the light receiving unit 427 that detects the x-axis coordinate value of the singular point of the signal waveform generated by In the light-receiving element 429, the number of times the passage number counting unit 222 counts the number of times that the same signal level as the singular point is repeatedly generated), the operation determination unit 223 that determines whether or not the scale member 44 is moving, and the pair of transmission units. The arrangement pitch of the 442 and the light shielding portion 443 (the transmission portion 44 of 1
The first movement amount calculation unit 224 that calculates the movement amount Mc that exceeds the value obtained by adding the width dimension of 2 and the width dimension of the light shielding unit 443 of 1, and the arrangement pitch of the set of the transmission unit 442 and the light shielding unit 443. The second movement amount calculation unit 225 that calculates the movement amount Ms within the range, the movement amount Mc calculated by the first movement amount calculation unit 223, and the movement amount Ms calculated by the second movement amount calculation unit 224. Each function realizing unit is provided as the movement amount adding unit 226 for adding the.

Here, the coordinate value detecting section 221 includes the light receiving section 4
Singular points of the signal waveform generated at 27 (see, for example, FIG.
The point a shown in (a) is detected by comparing the signal levels before and after the singular point, and the coordinate value of the x-axis is obtained from the position of the light receiving element 429 corresponding to the detected singular point. . The passage count counting unit 222 includes the scale member 44.
Of how many times the same signal level as the singular point (signal level before and after the singular point) is generated in the light receiving element 429 at the position corresponding to the singular point of the signal waveform immediately before the start of the movement. By counting, the number of passages of singular points is counted.

The operation discriminating section 223 has a predetermined light receiving element 429 (for example, the light receiving element 42 on the optical axis LS) set in advance.
It is determined whether the scale member 44 is moving, for example, by determining whether the signal level generated in 9) is fluctuating. That is, when the signal level of the predetermined light receiving element 429 fluctuates within the predetermined time, it is determined that the scale member 44 is moving, and when the signal level does not fluctuate within the predetermined time, the scale member 44 is moved. Is determined to be stopped.

The first movement amount calculator 224 receives the light receiving element 4 at the position corresponding to the singular point of the signal waveform immediately before the start of the movement of the scale member 44 obtained by the coordinate value detector 221.
The number of times a singular point (a singular point located at the same position as the previous singular point) of a signal waveform repeatedly generated by moving the scale member 44 passes through 29 (this light receiving element 429 is referred to as a starting end light receiving element 429). By multiplying (Nc) by the arrangement pitch (Pc) of the pair of transmissive portions 442 and the light shielding portions 443, the pair of transmissive portions 442 and the light shielding portions 443 are formed.
The moving amount Mc that exceeds the arrangement pitch of is calculated.

The second movement amount calculation unit 225 is a singular point of the signal waveform immediately after the movement of the scale member 44 is stopped (a singular point at the same position as the previous singular point), and is first detected by the coordinate value detection unit 221. It exists between the coordinate value of the singular point within the array pitch of the pair of transmissive portions 442 and the light shielding portions 443 from the obtained position of the starting light receiving element 429 and the previously obtained coordinate value of the starting light receiving element 429. By counting the number (Ns) of the light receiving elements 429 and multiplying the number (Ns) of the light receiving elements 429 by the arrangement pitch (Ps) of the light receiving elements 429 and the preset correction value (C), The movement amount Ms within the arrangement pitch of the pair of the transmission portion 442 and the light shielding portion 443 is calculated.

The movement amount summation unit 226 and the second movement amount calculation unit 2 calculate the movement amount Mc calculated by the first movement amount calculation unit 223.
The accurate amount of movement of the photographing lens LN, which is a moving object, is obtained by summing the amount of movement Ms calculated by 24.

As described above, the scale member 44 is once fixed to the engaging member 30 constituting the drive section 12 by an appropriate fixing means such as screwing or adhesion.
The engaging member 30 has a feeding direction indicated by an arrow a1 and an arrow a2.
When it moves in the return direction shown by, it can move together with the taking lens LN which is a moving object.

FIG. 9 is a flow chart for explaining the detecting operation of the moving amount of the moving object by the position detecting section 16. First, the drive unit 1 of the impact type actuator 10
The light emitting element driving unit 431 is operated in synchronization with the start of driving of the light emitting device 2 to drive the light projecting unit 425, and the irradiation light is output from the light projecting unit 425 to the light receiving unit 427 (step #
1). Then, the light receiving element driving section 432 is operated in response to the operation of the light emitting element driving section 431, so that the light receiving section 427 is activated.
Are driven (step # 3).

Then, immediately before the start of movement of the scale member 44 (that is, immediately before the start of driving of the drive unit 12), an electric signal generated by photoelectric conversion in the light receiving unit 427 is taken out from each light receiving element 429, and is received by the light receiving unit 427. The generated signal waveform immediately before the start of movement is stored in a storage unit such as a RAM that constitutes the control unit 22 (step #
5).

Next, based on the signal waveform stored in the storage means immediately before the start of movement, the coordinate value detection unit 221
The singular point of the signal waveform is detected by the method, and the coordinate value of the singular point is obtained and stored as the coordinate value (xa) of the singular point immediately before the start of movement in the storage means such as the RAM (step # 7). Then, the singular point of the signal waveform that is repeatedly generated while the scale member 44 is moving is a coordinate value (x
a), that is, the number of times (Nc) that the light-receiving element 429 corresponding to the position of the coordinate value (xa) passes.
Are counted by the passage count counter 222, and the counted number (Nc) is updated and stored in a storage means such as a RAM (step # 9).

Next, the operation discriminating section 223 discriminates whether or not the movement of the scale member 44 is stopped (step # 11). When this determination is affirmed, the electric signal generated by photoelectric conversion in the light receiving unit 427 immediately after the movement of the scale member 44 is stopped (that is, immediately after the driving of the driving unit 12 is stopped) is taken out from each light receiving element 429 and received. The signal waveform generated by the unit 427 immediately after the movement is stopped is stored in the storage means such as the RAM (step # 1).
3). If the determination in step # 11 is negative,
After shifting to step # 9, the subsequent steps are repeatedly executed.

Next, based on the signal waveform immediately after the movement is stopped stored in the storage means, the coordinate value detection unit 22
1 detects a singular point within one cycle, which is within the arrangement pitch of the pair of transmissive portions 442 and light-shielding portions 443, from the position (that is, the coordinate value (xa)) of the start light receiving element 429, and the singular point Is calculated and stored in the storage means such as RAM as the coordinate value (xb) of the singular point immediately after the movement is stopped (step # 15).

Next, at step # 9, the number of times (Nc) of passing through the starting end light receiving element 429 of the singular point of the signal waveform fetched in the storage means is read out, and the control section 22 is previously set.
The arrangement pitch (Pc) of the pair of transmissive portions 442 and the light shielding portions 443 stored in the storage means such as the ROM constituting the above is read, and the first movement amount calculation unit 224 sets the transmissive portions 442 and A movement amount Mc that exceeds the arrangement pitch of the light shielding portions 443 is calculated (step # 17).

Next, in step # 15, the coordinate value (xb) of the singular point within one cycle is read out from the start-end light receiving element 429 stored in the storage means, and the control section 2 is also set in advance.
The arrangement pitch (Ps) of the light receiving elements 429 and the correction value (C) stored in the storage means such as the ROM constituting the second unit 2 are read, and the read movement is calculated by the second movement amount calculation unit 225. The number (Ns) of the light receiving elements 429 existing between the coordinate value (xb) immediately after the stop and the coordinate value (xa) immediately before the start of the movement is counted, and the number of the light receiving elements 429 within the array pitch of the pair of the transmissive portions 442 and the light shielding portions 443 is counted. Is calculated (step # 19).

Finally, the movement amount Mc that exceeds the arrangement pitch of the pair of transmissive portions 442 and the light shielding portions 443 calculated in step # 17, and the pair of transmissive portions 442 and the light shielding portions 443 calculated in step # 19. Amount of movement within the array pitch of Ms
And are added together by the moving amount adding section 226 (step # 2).
1). As a result, an accurate amount of movement of the taking lens LN, which is a moving object, is obtained, and the obtained taking lens LN is obtained.
Is used for focus detection operation and the like.

FIG. 10 shows the second part of the mechanical section of the position detecting section 16.
It is a perspective view which decomposes | disassembles and shows the structural example which concerns on embodiment of this.
In this figure, the same components as those of the configuration example according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Hereinafter, different points will be mainly described. That is, the position detection unit (position detection device) 16 ′ according to the second embodiment includes the light detection unit 42 ′ and the scale member 44 ′.

The light detecting section 42 'is a flat plate rectangular support member 430 made of an insulating material such as a synthetic resin, and an LED arranged on the upper surface of the support member 430 at one end side in the longitudinal direction.
(Light Emitting Diode) or the like, and a light projecting unit 425 configured to emit the output light from the light emitting device obliquely upward, and visible light disposed on the light output surface of the light projecting unit 425. Cut filter 426 and support member 43
0 is disposed on the upper surface on the other end side in the longitudinal direction, and
CCD (Charge-Coupled Devic) that receives output light from
The light receiving unit 427 is a line sensor including a solid-state image sensor such as e). The light receiving unit 427 is
Since the scale member 44 ′ is configured to move in the space on the upper surface side of the support member 424 and along the line connecting the light projecting unit 425 and the light receiving unit 427 (the direction indicated by the arrow X), the light receiving Arrangement direction of elements 429 and scale member 4
It is arranged on the upper surface of the support member 430 so that the moving direction of 4 ′ substantially coincides.

The scale member 44 ′ has one end fixed to the engagement member 30 so as to be movable together with the engagement member 30. The scale member 44 ′ is provided on the elongated base plate 444 along the longitudinal direction thereof. A linear shape (for example, 0. 0) that reflects the output light (irradiation light) from the light projecting unit 425 and guides it to the light receiving unit 427.
1 mm wide) reflection part (light guide part) 445 and light projection part 425
The non-reflecting portions (non-light guiding portions) 446 having a linear shape (for example, 0.1 mm width) for preventing the output light from the above from being transmitted upward and not being guided to the light receiving portion 427 are alternately formed and reflected. Direction of arrangement of the portion 445 and the non-reflection portion 446 and the light receiving portion 42
The light receiving element 429 is arranged movably in the photodetection section 42 'so that the arrangement direction of the light receiving elements 429 of No. 7 is substantially the same.

That is, the scale member 44 'is formed by repeatedly arranging a set of a reflecting portion 445 and a non-reflecting portion 446 in a linear direction at a predetermined arrangement pitch (for example, 0.2 mm). A long substrate 444 made of
Was obtained by continuously forming a plurality of linear (for example, 0.1 mm width) through-holes to be non-reflective portions at a predetermined interval (for example, 0.1 mm interval) by a hole forming means such as etching. It is a thing. According to this configuration, the area where the through hole is not formed becomes the reflection section 445, and the area where the through hole is formed becomes the non-reflection section 446.

FIG. 11 is a diagram for explaining the principle of detecting the amount of movement of a moving object by the position detecting unit 16 '. FIG. 11A shows the scale member 44' constituting the position detecting unit 16 'immediately before the start of movement. Shows the state when in the first position, (b)
Is the scale member 44 'from the first position to the pair of reflectors 4
45 and the non-reflecting portion 446 array pitch (for example, 0.2
mm), that is, the width dimension of the reflection section 445 (for example,
0.1 mm) and the width dimension of the non-reflecting portion 446 (for example, 0.1
mm) and a width dimension (for example, 0.2 mm) added together, a state is shown where the second position on the right side of the drawing is moved by a slight distance.

Now, the scale member 44 'is shown in FIG.
In the first position shown in FIG.
Since the reflection part 445 of the above is located on the intermediate axis LT which is an intermediate position between the light projecting part 425 and the light receiving part 427 (however, it is not limited to the case where the reflection part 445 is located on the intermediate axis LT). The output light from the light projecting unit 425 is reflected by the reflecting unit 445 on the intermediate axis LT and is applied to the light receiving element 429 in the predetermined region of the light receiving unit 427. In this case, of the plurality of light receiving elements 429 irradiated with the output light from the light projecting unit 425, the predetermined width W10 (scale member 4
The maximum amount of light is applied to the plurality of light receiving elements 429 existing within the width (corresponding to the shaded portion between 4'and the light receiving portion 427), but the predetermined width W11 adjacent to both left and right sides of the predetermined width W10.
Each of the plurality of light receiving elements 429 existing within (the width corresponding to the shaded portion between the scale member 44 'and the light receiving portion 427) and within the width W12 (the width corresponding to the shaded portion between the scale member 44' and the light receiving portion 427). Therefore, the amount of light emitted gradually decreases as the distance from the position of the width W10 increases.

Therefore, the signal waveform photoelectrically converted and output from the light receiving section 427 (the signal waveform formed according to the signal level generated in each light receiving element 429) has a trapezoidal shape as shown in the figure. Becomes One cycle of this signal waveform corresponds to the arrangement pitch (for example, 0.2 mm) of the pair of the reflecting portion 445 and the non-reflecting portion 446 of the scale member 44 ′, which is 2
It corresponds to the doubled value (for example, the scale member 4
Assuming that the distance between 4 ′ and the light receiving unit 427 is substantially zero, one period of the signal waveform is 0.4 mm. ). It should be noted that this signal waveform corresponds to the scale member 44 ′ and the light receiving portion 42.
Width W11 and width W1 as the distance between
Since 2 becomes narrower, it becomes closer to a rectangular shape.

Then, when the scale member 44 'at the first position shown in FIG. 11A moves to the second position shown in FIG. 11B, the positions of the reflecting portion 445 and the non-reflecting portion 446 are changed. Since it moves to the right, both the region of the light receiving unit 427 that is irradiated with the output light from the light projecting unit 425 and the region that is not irradiated are moved to the right. Therefore, the signal waveform output from the light receiving unit 427 also moves to the right as shown. In this example, the signal waveform is as shown in FIG.
The trapezoidal part shown in FIG.

Here, the horizontal axis (time axis) of the signal waveform is set as the x axis, the position of the central axis LS of the light receiving portion 427 is set as the reference point (zero), and the scale member 44 'is set to the first position in FIG. When the coordinate value of the singular point of the signal waveform at the position of 1 (point at which the position of the waveform can be specified), for example point b (starting start point of the trapezoidal shape portion) is x3, this scale member When 44 ′ moves to the second position in FIG. 11B, the point b moves to the right, and the coordinate value of the point b at that time becomes x4.

Therefore, the number of light receiving elements 429 between the coordinate values x3 and x4 is counted, and the count value (N of the light receiving elements 429 is set to the array pitch (Ps) of the light receiving elements 429).
s), and a value obtained by halving the multiplication result value is multiplied by a correction value (C) corresponding to the distance between the scale member 44 ′ and the light receiving unit 427, to thereby obtain the scale member 44 ′. Can be obtained. That is, the moving amount Ms ′ of the scale member 44 ′ is Ms ′ = Ps × Ns.
It can be obtained by the formula of × 0.5 × C. The correction value (C) becomes "1" when the distance between the scale member 44 'and the light receiving unit 427 is substantially zero, and becomes smaller than "1" as the distance increases. It becomes a value. Therefore, this correction value (C) may be calculated in advance or experimentally obtained.

For example, the pitch (Ps) of the light receiving elements 429
Is 0.005 mm, the scale member 44 'and the light receiving section 42
If the number (Ns) of the light receiving elements 429 between the coordinate values x3 and x4 is 20 when the distance between the light receiving elements 429 is substantially zero, the arrangement pitch (Ps) of the light receiving elements 429 becomes 0.005 m multiplied by the number of light receiving elements 429 (Ns)
m × 20 pieces × 0.5 × 1 = 0.05 mm is the scale member 4
This is a movement amount of 4 '. Since the scale member 44 'moves together with the taking lens LN which is a moving object, the obtained moving amount of the scale member 44' becomes the moving amount of the taking lens LN which is a moving object. The + area on the right side of the reference point of the x-axis is the direction in which the engaging member 30 moves in the feeding direction, and the − area on the left side of the reference point of the x-axis is the engaging member 3.
By setting 0 as the moving direction in the returning direction, the moving direction can be obtained at the same time as the moving amount of the taking lens LN.

As described above, the movement amount is detected within the range of the arrangement pitch (for example, 0.2 mm) of the set of the reflecting portion 445 and the non-reflecting portion 446, as in the case of the first embodiment. "Detection", and the arrangement pitch of the light receiving elements 429 in the light receiving unit 427 (for example, 0.005 mm)
It is possible to obtain a fine resolution up to a half value. In addition, in order to enable this "fine position detection",
The light-receiving unit 427 needs to have a length dimension (that is, two pitches) that is twice as large as the arrangement pitch (for example, 0.2 mm) of at least one set of the reflection unit 445 and the non-reflection unit 446. That is, assuming that the array pitch of the light receiving elements 429 in the light receiving section 427 is, for example, 0.005 mm, at least 80 (when the distance between the scale member 44 ′ and the light receiving section 427 is substantially zero) Element 42
9 must be arranged.

On the other hand, a set of the reflecting portion 445 and the non-reflecting portion 4 is provided.
The detection of the movement amount exceeding the arrangement pitch of 46 (for example, 0.2 mm) is also referred to as "coarse position detection" in the second embodiment, and this "coarse position detection" can be executed as follows. it can. That is, the signal level output from the light receiving element 429 corresponding to the position of the coordinate value x3 of the point b which is the singular point of the signal waveform shown in FIG. As shown in FIG. 12, the shape changes to a shape similar to the trapezoidal shape in FIG. 11.

Although the signal level of the light receiving element 429 at the coordinate value x3 of the point b of the signal waveform shown in FIG. 11A is "0", the scale member 44 'is moved to the right in the figure, for example. Signal level rises due to
When the 45 and the non-reflecting portion 446 have finished moving (that is, the scale member 44 'has one pitch (for example, 0.2 m
m) When the movement is completed), the signal level of the light receiving element 429 at the coordinate value x3 returns to "0" again. Further, when the scale member 44 ′ moves to the right in the figure, the signal level rises again, but at the time when the set of the reflecting portion 445 and the non-reflecting portion 446 has finished moving (that is, the scale member 44 ′ has two pitches ( For example, the signal level of the light receiving element 429 at the coordinate value x3 will return to "0" three times at the time of the completion of the movement (0.4 mm).

Therefore, the light receiving element 4 located at this coordinate value x3
The number of times that the signal level of 29 becomes “0” after the movement of the scale member 44 ′ is started is counted, and a set of the reflection unit 445 is provided.
Also, the movement amount of the scale member 44 ′ can be obtained by multiplying the arrangement pitch (Pc) of the non-reflecting portions 446 by the number of times (Nc) when the signal level becomes “0”. That is, the moving amount Mc 'of the scale member 44' is Mc '= P
It can be obtained by the formula of c × Nc.

For example, if the arrangement pitch (Pc) of the pair of reflecting portions 445 and the non-reflecting portions 446 is 0.2 mm and the number of times the signal level becomes “0” (Nc) is 3, one pair of Arrangement pitch (Pc) of the reflection part 445 and the non-reflection part 446
Is multiplied by the number of times the signal level has become “0” (Nc), and the amount of movement of the scale member 44 ′ is 0.2 mm × 3 = 0.6 mm. Since the scale member 44 'moves together with the photographing lens LN which is a moving object, the obtained movement amount of the scale member 44' is the photographing lens LN which is a moving object.
Is the amount of movement. If you move to the right side of the x-axis,
As a direction in which the engaging member 30 moves in the feeding direction,
By taking the case of moving to the left side of the x-axis as −, and setting the direction in which the engaging member 30 moves in the returning direction, the taking lens L
The moving direction can be obtained at the same time as the moving amount of N.

As described above, the "fine position detection", which is the detection of the movement amount within the range of the arrangement pitch (for example, 0.2 mm) of the pair of the reflecting portion 445 and the non-reflecting portion 446,
The "coarse position detection", which is the detection of the movement amount exceeding the arrangement pitch (for example, 0.2 mm) of the pair of the reflecting portion 445 and the non-reflecting portion 446, is executed at the same time, and those two types of movement amounts are set. An accurate amount of movement of the taking lens LN can be obtained by adding Ms 'and the amount of movement Mc'.

The control configuration of the position detecting unit 16 'is similar to that of the position detecting unit 16 according to the first embodiment shown in FIG. 8, and the position detecting unit 16' detects the moving amount of the moving object. The operation is the same as that shown in the flowchart of FIG. 9 of the position detecting unit 16 according to the first embodiment, and thus the description thereof will be omitted.

Returning to FIG. 1, the base end sensor 18 and the tip end sensor 20 are constituted by appropriate sensors such as a photo interrupter. As a result, the position of the engaging member 30 is detected by the proximal end sensor 18 and the distal end sensor 20, and further movement of the engaging member 30 is prohibited. Also,
The control unit 22 executes the CP as described above.
U, ROM for storing control programs and various data, and RAM for temporarily storing data,
The drive circuit unit 14 is drive-controlled based on the signals input from the position detection unit 16, the base end sensor 18, and the front end sensor 20.

As described above, according to the position detectors (position detectors) 16 and 16 'applied to the impact type actuator 10 according to the embodiment of the present invention, the light guide portions (of the scale members 44 and 44') ( Transmission part 442, reflection part 445)
The area where the output light from the light projecting section 425 is irradiated by and the area where the output light from the light projecting section 425 is not irradiated by the non-light guide sections (the light shielding section 443 and the non-reflecting section 446) of the scale members 44 and 44 '. Is formed along the arrangement direction of the light receiving element 429 of the light receiving section 427, and the signal waveform generated in the light receiving section 427 moves along with the movement of the scale members 44, 44 '. The shooting lens LN
The amount of movement is detected.

Therefore, the positions of the singular points (feature points) of the signal waveform generated by the light receiving section 427 are set to the scale members 44, 4
By performing the detection before the movement of 4 ′, the scale members 44, 4 are assembled when the position detection units 16, 16 ′ are assembled.
Even when the positional relationship between 4 ′ and the light receiving unit 427 is not accurately set, the moving amount of the moving object can be accurately detected.

In addition, a set of light guide portions (transmission portion 442, reflection portion 445) and non-light guide portions (light shielding portion 443, non-reflection portion 44).
6) the amount of movement exceeding the arrangement pitch, and a pair of the light guide section (transmission section 442, reflection section 445) and the non-light guide section (light shield section 44).
3, the amount of movement of the non-reflecting portions 446) within the arrangement pitch is calculated separately, so that the number of light receiving elements 429 arranged can be small, and thus the light receiving portion 427 can be downsized. Therefore, it is possible to realize a position detection unit (position detection device) that can accurately detect the amount of movement of a moving object with a relatively simple configuration.

The present invention is not limited to the above embodiment, and various modifications such as those described below can be adopted as necessary.

(1) In the above embodiment, the scale member 4
4, 44 'are configured to have an elongated shape and detect the amount of movement of the moving object in the linear direction, but the present invention is not limited to this. For example, the scale members 44 and 44 'may be configured to have a disc shape so as to rotate and move, and the amount of movement of the moving object in the circumferential direction may be detected.
In this case, a light guide section (transmission section 442 or reflection section 445) configured to guide the irradiation light from the light projecting section 425 to the light receiving section 427.
The non-light-guiding portions (the light-shielding portions 443 and the non-reflecting portions 446) that are not guided to the light-receiving portion 427 may be arranged at a predetermined array pitch in the circumferential direction.

That is, as a light guide section for passing the output light from the light projecting section 425 and guiding it to the light receiving section 427, a transmitting section similar to that shown in FIG. 5 is provided, and the output light from the light projecting section 425 is provided. In the case where a light-shielding portion similar to that shown in FIG. 5 is provided as a non-light-guiding portion that blocks the light and is not guided to the light receiving portion 427, for example, as shown in FIG.
It may be formed in a disk shape in which the transmissive portions 448 and the light shielding portions 449 are alternately and repeatedly arranged in the circumferential direction on the 47. Further, the same configuration can be achieved even when a reflection part similar to that shown in FIG. 10 is provided as the light guide part and a non-reflection part similar to that shown in FIG. 10 is provided as the non-light guide part.

As described above, when the scale member is formed in a disc shape, the scale member is rotated about the center point O of the substrate 447 in the circumferential direction indicated by the arrow D in association with the moving object,
The light guide section (transmission section 448 and the like) and the non-light guide section (light shield section 449 and the like) within the predetermined center angle are the light receiving elements 4 of the light receiving section 427.
It may be arranged so as to move in the arrangement direction of 29. In addition, the disc-shaped scale member is fixed in position, and the light receiving unit 42
It is also possible to rotate 7 in conjunction with a moving object. In short, it suffices that the scale member and the light receiving section rotate relative to each other so that the light guide section and the non-light guide section can move relative to the light projecting section and the light receiving section.

In this case, since the widths of the light guide portion and the non-light guide portion are different between the center side (inner diameter side) and the outer peripheral side (outer diameter side) of the circle, the amount of light irradiated to the light receiving section 427 is different. The center side and the outer side of the circle will be different, but signal processing will be performed based on the amount of light at locations where the width dimension is the same from the center and the width dimension is the same, and An accurate position in the rotation direction can be detected by obtaining the average value of the light amount in (1) and performing the signal processing (by obtaining the center of gravity of the light flux).

(2) The scale member 44 in the first embodiment of the above-mentioned embodiments is a transparent long substrate 44.
It is obtained by continuously forming a plurality of linear light-shielding film bodies serving as a light-shielding portion on the substrate 1 at predetermined intervals by a film-body forming means such as printing or plating, but the invention is not limited to this. For example, it can also be obtained by continuously forming a plurality of linear transmission holes, which are transmission portions, at a predetermined interval by a hole forming means such as an etching process on a long metal plate along the longitudinal direction thereof.

(3) In the above embodiment, the light receiving section 427
Is a line sensor in which a plurality of light receiving elements are arranged one-dimensionally, but is not limited to this. For example, it is possible to use an area sensor in which a plurality of light receiving elements are two-dimensionally arranged. In this case, it is possible to detect the two-dimensional movement of the moving object. Further, the light receiving unit 427 can also be configured with a CMOS sensor.

(4) In the above embodiment, the scale member 4
Although the reference numerals 4 and 44 'are moved with respect to the position-fixed photodetection sections 42 and 42' (light projecting section 425 and light receiving section 427), the present invention is not limited to this. For example,
It is also possible to fix the positions of the scale members 44 and 44 'and move the photodetection units 42 and 42'. In this case, the light detectors 42 and 42 'may be attached to the engaging member 30 to which the moving object is attached. The point is that the scale members 44, 44 'may be moved relative to the light detection units 42, 42' together with the moving object.

(5) In the above embodiment, the scale member 4
The reference numerals 4 and 44 'are configured to directly face the light receiving section 427, but the configuration is not limited to this. For example, by disposing an optical system such as an optical lens between the scale members 44 and 44 ′ and the light receiving unit 427, it is possible to suppress the spread of the light flux and thereby improve the detection accuracy of the moving amount of the moving object. Is also possible.

(6) In the above embodiment, the impact type actuator 10 to which the position detecting device (position detecting unit) according to the present invention is applied is described as being used in a camera, but the present invention is not limited to this. . For example, it can be applied to various electric devices such as a measuring device that measures a moving distance of a moving object. Further, the position detection device (position detection unit) according to the present invention can be applied to drive devices having various configurations other than the impact type actuator.

(7) In the above embodiment, the rising start point of the trapezoidal portion (point a in FIG. 6 and point b in FIG. 11) is used as the singular point of the signal waveform generated in the light receiving section 427. However, it is not limited to this. For example, the rising end point of the trapezoidal portion or the falling end point of the trapezoidal portion can be used as the singular point of the signal waveform. In short,
Along with the movement of the scale members 44, 44 ', the light receiving unit 427
Any point may be specified as long as the position of the signal waveform sequentially generated can be specified.

(8) In the above embodiment, the movement amount Mc that exceeds the arrangement pitch of the pair of the light guide section (transmission section 442 and reflection section 445) and the non-light guide section (shield section 443 and non-reflection section 446), Mc ', and a pair of light guide portions (transmission portion 442 and reflection portion 445) and non-light guide portions (light shielding portion 443 and non-reflection portion 4).
46) movement amounts Ms, M within the arrangement pitch range
Although s'is obtained using a predetermined calculation formula,
It is not limited to this. For example, the movement amount obtained by a predetermined calculation formula may be collected in advance in a table and stored in the storage means, and the movement amount may be obtained by reading from the table of the storage means.

(9) In the above embodiment, the visible light cut filter 426 is arranged on the light output surface of the light projecting section 425, but the invention is not limited to this. For example, when using a light emitting element that outputs only infrared light from the light projecting unit 425 and does not output visible light, or when it is applied to a device that outputs visible light but has no risk of affecting other things, etc. Then, it is not necessary to use the visible light cut filter 426.

Further, as shown in FIG. 14, when the impact type actuator 10 to which the position detecting units 16 and 16 'according to the present invention are applied is used in a digital camera, the image is stored in an image pickup device 58 such as a CCD for taking in a subject image. The picked-up image signal is taken out to a storage medium (storage means) 60
When the moving amount of the photographing lens 54 is detected by outputting the irradiation light from the light projecting unit 425 during the transfer to the image capturing unit 425, the image is output by the output light including the visible light from the light projecting unit 425. The influence on the element 58 can be eliminated, and thus the visible light cut filter 426 can be eliminated.

That is, in FIG. 14, the digital camera 50 comprises a camera body 52 and a lens barrel 56 having a taking lens 54 disposed therein. On the camera body 52 side,
An image sensor 58 including an area sensor such as a CCD that captures a subject image, a storage medium 60 that stores an image signal,
A main body controller 62 for controlling the operations of the image pickup device 58 and the storage medium 60 is provided. The main body control unit 62 includes a timer 64 for synchronizing the entire operation.
Are connected. Further, the impact type actuator 10 is arranged together with the control unit 22 on the lens barrel 56 side. In this configuration, the control unit 22 is synchronized by the timer 64 that outputs the clock signal of the main body control unit 62, and the operation of the impact type actuator 10 is controlled.

Therefore, as described above, the image pickup device 58
Irradiation light can be output from the light projecting unit 425 during transfer of the image pickup signal of (1) to the storage medium (storage unit) 60. Further, since the control unit 22 is controlled by being synchronized with the timer 64 of the main body control unit 62, it is not necessary to provide the control unit 22 with a timer that outputs a clock signal, so that the cost can be reduced. further,
When the main body control unit 62 is provided with the function of the control unit 22 (that is, the control unit 22 is configured by the main body control unit 62), the control unit 22 is not necessary, so that the cost can be reduced. .

[0108]

As described above, according to the present invention,
An arrangement direction of the light receiving element of the light receiving unit is defined by a region where the light guiding unit of the scale member emits the output light from the light emitting unit and a region where the non-light guiding unit of the scale member does not emit the output light from the light emitting unit. The movement amount of the moving object is detected by utilizing the fact that the signal waveform generated in the light receiving unit moves along with the movement of the scale member by being formed along the line. With the configuration, the moving amount of the moving object can be accurately detected.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a configuration of an impact type actuator to which a position detection device according to an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a configuration example of a drive unit of the impact type actuator shown in FIG.

3 is a block diagram showing a configuration example of a drive circuit of the impact type actuator shown in FIG.

FIG. 4 is a diagram showing a relationship between a drive voltage applied to the electromechanical conversion element of the impact type actuator shown in FIG. 1 and a displacement waveform due to expansion and contraction of the electromechanical conversion element, in which (a) is a duty ratio of the drive voltage. Is set to 0.3, and (b) is set to set the duty ratio of the drive voltage to 0.7.

5 is an exploded view showing a configuration example of the position detection unit of the impact type actuator shown in FIG. 1 according to the first embodiment. FIG.

6A and 6B are diagrams for explaining the principle of detecting the amount of movement of a moving object by the position detection unit shown in FIG. 5, in which FIG. 6A shows a state when the scale member is at the first position which is the initial position. , (B) are diagrams showing a state when the scale member moves from the first position to the second position.

7 is a diagram showing changes in the signal level output from the light receiving element corresponding to the positions of the singular points of the signal waveform shown in FIG.

8 is a block diagram showing a control configuration of a position detection unit shown in FIG.

9 is a flowchart for explaining the operation of detecting the amount of movement of a moving object by the position detection unit shown in FIG.

FIG. 10 is an exploded view showing a configuration example of a position detection unit of the impact type actuator shown in FIG. 1 according to a second embodiment.

11A and 11B are diagrams for explaining the principle of detecting the amount of movement of a moving object by the position detection unit shown in FIG. 10, in which FIG. 11A shows a state when the scale member is at the first position which is the initial position. , (B) are diagrams showing a state when the scale member moves from the first position to the second position.

12 is a diagram showing changes in the signal level output from the light receiving element corresponding to the positions of the singular points of the signal waveform shown in FIG.

FIG. 13 is a diagram showing an example of a case where the scale member forming the position detection unit of the impact type actuator shown in FIG. 1 is formed into a disc shape.

FIG. 14 is a structural diagram showing an example in which an impact type actuator to which the position detecting device according to the present invention is applied is used in a digital camera.

[Explanation of symbols]

10 Impact type actuator 16, 16 'Position detection unit (position detection device) 22 Control unit 44,44 'Scale member 50 digital camera 54 Shooting lens 62 Main body control unit (motion control unit) 224 First movement amount detection unit (movement amount detection means) 225 Second Movement Amount Detection Unit (Movement Amount Detection Means) 226 Moving amount adding section (moving amount detecting means) 425 Projector 426 Visible Light Filter 427 Light receiving part 429 light receiving element 442 Transmission part (light guide part) 443 Light-shielding part (non-light guide part) 445 Reflecting part (light guiding part) 446 Non-reflecting part (non-light guiding part) LN shooting lens (moving object)

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA07 AA09 BB18 FF15 FF44                       GG07 GG12 HH04 HH13 JJ02                       JJ25                 2F103 BA37 BA43 CA02 CA03 DA01                       DA12 EA03 EA15 EA19 EA21                       EB06 EB14 EB32 EB33 EC16                       ED21 ED27 FA11                 2H044 BE18 DE06

Claims (10)

[Claims] 1. A position detecting device for detecting the amount of movement of a moving object, comprising: a light projecting unit for radiating output light in a predetermined direction.
A light receiving section in which a plurality of light receiving elements for receiving the output light from the light projecting section are arranged in a predetermined direction, and a light guide section and a guiding section for guiding the output light from the light projecting section to the light receiving section. The non-light-guiding sections are arranged alternately and repeatedly so that the light-guiding sections and the non-light-guiding sections can move relative to the light-projecting section and the light-receiving section while being alternately arranged. The scale member disposed on the scale member, the region where the output light from the light projecting unit is irradiated by the light guide unit of the scale member, and the output light from the light projecting unit by the non-light guide unit of the scale member. The moving object is utilized by utilizing that the non-illuminated area is formed in the arrangement direction of the light receiving element of the light receiving section, and the signal waveform generated in the light receiving section moves with the relative movement of the scale member. And a moving amount detecting means for detecting the moving amount of Position detecting apparatus according to claim. 2. The movement amount detecting means sums up a first movement amount exceeding the arrangement pitch of the light guide portions and non-light guide portions of the scale member and a second movement amount within the arrangement pitch. The moving amount of the moving object is detected by the first moving amount, and in the first moving amount, the singular point of the signal waveform repeatedly generated in the light receiving unit by the relative movement of the scale member starts the relative movement of the scale member. It is obtained based on the product of the number of times of passing through the light receiving element at the position corresponding to the singular point of the previous signal waveform and the arrangement pitch of the light guide section and the non-light guide section of the scale member. Is the singular point of the signal waveform after the relative movement of the light receiving element and the scale member at the position corresponding to the singular point of the signal waveform before the relative movement of the scale member is started before the relative movement is started. Supports singular points of signal waveform The number of light receiving elements existing between the light receiving elements at positions corresponding to singular points within the arrangement pitch of the light guide portions and the non-light guide portions of the scale member from the light receiving elements at the positions, and the arrangement pitch of the light receiving elements. The position detecting device according to claim 1, wherein the position detecting device is obtained based on a product of 3. The light projecting portion and the light receiving portion are arranged to face each other, and the scale member is configured such that the light guide portion and the non-light guide portion are repeatedly arranged in a linear direction at a predetermined pitch. The light guide section and the non-light guide section are arranged so as to be relatively movable between the light projecting section and the light receiving section so that the arrangement direction of the light guide section and the non-light guide section coincides with the arrangement direction of the light receiving element. The position detecting device according to claim 1 or 2, wherein 4. The light receiving section is such that the light receiving elements are arranged at a finer pitch than the arrangement pitch of the light guide section and the non-light guide section of the scale member, and at least the light guide section and the non-light guide section. 4. The position detecting device according to claim 3, wherein the position detecting device has a length dimension corresponding to one pitch of the parts. 5. The light projecting portion and the light receiving portion are arranged side by side along an arrangement direction of light receiving elements of the light receiving portion, and the scale member includes the light guide portion and the non-light guide portion. Are repeatedly arrayed in a linear direction at a predetermined pitch, and the light projecting section and the light receiving section are arranged so that the array direction of the light guide section and the non-light guide section and the array direction of the light receiving element match. The position detecting device according to claim 1 or 2, wherein the position detecting device is arranged so as to be opposed to and relatively movable. 6. The light receiving section is such that the light receiving elements are arranged at a pitch smaller than the arrangement pitch of the light guide section and the non-light guide section of the scale member, and at least the light guide section and the non-light guide section. The position detecting device according to claim 5, wherein the position detecting device has a length dimension twice as large as the arrangement pitch of the parts. 7. The position detecting device according to claim 1, wherein a visible light cut filter is provided on a light output surface of the light projecting portion. 8. A built-in digital camera having an image pickup device, wherein the movement amount detecting means is constituted by an operation control section for controlling the operation of the digital camera. The position detection device according to any one of 1 to 7. 9. The light projecting unit is controlled to output irradiation light during transfer of an image pickup signal accumulated in the image pickup device to the outside of the image pickup device. Item 8. The position detection device according to item 8. 10. The scale member has a disc shape in which the light guide portions and the non-light guide portions are repeatedly arranged in a circumferential direction at a predetermined pitch, and the scale member has a disc shape with respect to the light emitting portion and the light receiving portion. 3. The light guide portion and the non-light guide portion are relatively movable with respect to the light projecting portion and the light receiving portion by rotating relative to each other. Position detection device.