JP2003280056A - Vibration detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration detection device capable of accurately detecting zero angular velocity and eliminating a dead time after changing over a switch. <P>SOLUTION: The vibration detection device is provided with switching parts SWA, SWB for cutting off a detected vibration signal before or after a capacitor 10 forming a bypass filter 8X, and in the cut-off state, an output is detected at a standstill when there is no vibration in the vibration detection part 5, and the output at the standstill in a state in which no vibration in the vibration detection part 5 is detected by the vibration detection part 20. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration detection device for determining a stationary output voltage of an angular velocity sensor that generates an output voltage according to the magnitude of a rotational angular velocity, and more particularly to a camera shake correction in a digital camera or an analog camera. The present invention relates to a device for determining a static output of a vibration detection circuit used in.

[0002]

2. Description of the Related Art A camera shake detecting device disclosed in Japanese Patent Laid-Open No. 7-218953 includes an angular velocity sensor, an HPF (high-pass filter), an amplifier circuit, and a CPU. When the release button is half-pressed, the angular velocity sensor is powered. By supplying and turning on the analog switch, the shake signal input to the amplifier is forcibly replaced with a (DC) zero level signal, then the analog switch is turned off, and the output of the amplifier circuit is A / D converted. To detect zero angular velocity,
Then, when the output of the amplifier circuit reaches the zero angular velocity detection value,
The CPU turns on the analog switch once to reduce the offset value, then turns off the analog switch, and thereafter continues to perform zero angular velocity detection to calculate the zero angular velocity detection value and calculate the angular velocity from the A / D conversion output. The zero detection value is subtracted to obtain the true angular velocity, that is, the amount of camera shake.

[0003]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
According to the invention described in Japanese Patent No. 218953, by turning on an analog switch, a shake signal input to an amplifier is forcibly replaced with a (DC) zero level signal. As compared with the impedance of the level signal system, the impedance of the signal system in the front stage of the amplifier is also low, and the vibration detection signal is superposed to be a zero level signal, so that there is a disadvantage that accurate zero angular velocity detection cannot be performed.

Further, since the DC level in the latter stage of the HPF is forcibly set to zero level, the capacitor constituting the HPF is charged / discharged for a while after the analog switch is turned off, so that the shake cannot be detected. Has become.

An object of the present invention is to solve the above-mentioned problems of the prior art, to provide a vibration detecting device capable of accurately detecting zero angular velocity and eliminating the dead time after switching the switch.

[0006]

In order to achieve the above object, the invention as set forth in claim 1 includes a vibration detecting section for detecting vibration and outputting a vibration detection signal, and a reference voltage supplied to the vibration detecting section. A reference voltage generator that generates a high-pass filter that blocks the DC component of the vibration detection signal to eliminate the effect of drifting the vibration detection signal when stationary, and a vibration detection signal that passes through this high-pass filter and the reference In a vibration detection device including a differential amplification unit that outputs a vibration signal by differentially amplifying a voltage and a vibration detection unit for detecting the vibration signal, before or after a capacitor that constitutes the high-pass filter unit. A switch unit for disconnecting the transmission of the vibration detection signal is provided, and the output at rest when the vibration detection unit has no vibration in the disconnected state is detected. And symptoms, this configuration still at the output of the absence of vibration in the vibration detection unit is exactly the vibration detection unit, so that can be detected with a simple circuit configuration.

According to a second aspect of the present invention, in the vibration detecting apparatus according to the first aspect, a switch section is provided in a stage before the resistor forming the high pass filter section and in a stage subsequent to the capacitor forming the high pass filter section. Characteristically, this configuration does not charge or discharge the filter capacitor that constitutes the high-pass filter unit, so that the output at rest can be detected in a short time.

According to a third aspect of the present invention, a vibration detecting section for detecting a vibration and outputting a vibration detecting signal, a reference voltage generating section for generating a reference voltage supplied to the vibration detecting section, and a stationary vibration detecting signal. Vibration by eliminating the direct current component of the vibration detection signal in order to eliminate the influence of drift of the time output, and by differentially amplifying the vibration detection signal and the reference voltage that have passed through the first high pass filter section. A first differential amplifier that outputs a signal; a second high-pass filter that blocks a DC component of the vibration signal; and a first differential amplifier that differentially amplifies the vibration signal and the reference voltage that have passed through the second high-pass filter. A second differential amplifier that outputs two vibration signals;
A vibration detecting device comprising a vibration detecting unit for detecting a vibration signal, comprising a switch unit for cutting off the transmission of the vibration detecting signal at a stage subsequent to the capacitor constituting the second high pass filter, and the vibration detecting unit in the cut state. It is characterized by detecting the output at rest when there is no vibration in the vibration detection unit.This configuration allows the vibration detection unit to accurately detect the output at rest when there is no vibration in the vibration detection unit with a simple circuit configuration. You can do it. Furthermore, since the filter capacitor that constitutes the high-pass filter is not charged or discharged, the output at rest can be detected in a short time, and the configuration of the AC two-stage amplifier circuit can cancel the output drift caused by the offset voltage of the differential amplifier. Since the offset adjustment circuit can be deleted, it is possible to eliminate the output variation of the second vibration signal due to the power supply voltage variation or the temperature variation of the offset adjustment circuit. Moreover, the time or man-hours associated with the adjustment can be eliminated.

According to a fourth aspect of the present invention, in the vibration detecting device according to the third aspect, a switch section for disconnecting the transmission of the vibration detection signal is provided before or after the capacitor forming the second high-pass filter, and the first aspect. A high-pass filter unit and a starting circuit unit that variably controls the time constants of the second high-pass filter unit are provided. With this configuration, the normally-occurring starting circuit unit is diverted,
The output at rest when there is no vibration in the vibration detector can be accurately detected by the vibration detector in a short time with a simple circuit configuration. Further, since the AC two-stage amplifier circuit is configured, the output drift caused by the offset voltage of the differential amplifier can be canceled. Further, since the offset adjustment circuit can be deleted, the second adjustment due to the power supply voltage fluctuation or temperature fluctuation of the offset adjustment circuit
The output fluctuation of the vibration signal can be eliminated. Moreover, the time and man-hours associated with the adjustment can be deleted.

According to a fifth aspect of the present invention, in the vibration detecting device according to the third aspect, the reference voltage is output at a stationary time when the vibration detecting section has no vibration. By using the static output when there is no vibration in the section as the reference voltage, it is possible to detect the static output with a simple circuit configuration without providing a separate switch section. Since it does not depend on the discharge, the output at rest can be detected in a short time. In addition, because the configuration of the AC two-stage amplifier circuit,
The output drift caused by the offset voltage of the differential amplifier can be canceled. Since the offset adjustment circuit can be deleted,
It is possible to eliminate the output fluctuation of the second vibration signal due to the power supply voltage fluctuation or the temperature fluctuation of the offset adjustment circuit. In addition, the time or man-hours associated with the adjustment can be deleted.

According to a sixth aspect of the present invention, in the vibration detecting device according to the first to fourth aspects, a control section for controlling opening and closing of the switch section is provided.
By providing a control unit that controls the opening and closing of the switch unit, the vibration detection unit can detect the static output when there is no vibration in the vibration detection unit at any time, and the reference voltage or the offset voltage of the differential amplifier can be detected. It becomes possible to compensate for fluctuations in the output at rest due to fluctuations in power supply voltage, fluctuations in temperature, changes over time, etc., and it becomes possible to always detect accurate output at standstill.

[0012]

1 is an external perspective view for explaining an embodiment of an image pickup apparatus with a camera shake correction function according to the present invention. In the image pickup apparatus 1, 2 is an image pickup lens, and 3 is an image pickup optical system. Reference numeral 4 denotes a release switch, and when the XY axes are taken as shown in FIG. 1, when the release switch 4 is pressed, a shake around the X axis and a shake around the Y axis orthogonal thereto occur.

FIG. 2 is an explanatory view showing a main part of a configuration for realizing a basic shake correction method in the photographing apparatus. Reference numerals 5 and 6 are vibration detection parts such as a vibration angular velocity sensor, and one vibration The detection unit 5 detects shake of the photographing apparatus around the X axis, and the other vibration detection unit 6 detects shake of the photographing apparatus around the Y axis. Reference numeral 8 is a high-pass filter unit that blocks a direct current component of the vibration detection signals from the vibration detection units 5 and 6, 9 is a differential amplification unit that amplifies the vibration detection signal, 14 is an image pickup means including an image pickup device 7 such as a CCD, 15 Indicates a pressurizing spring for position regulation.

The vibration signal output from the differential amplifier 9 is AD
It is sent to the arithmetic processing means 10 which has a vibration detection unit described later such as a converter. The arithmetic processing means 10 is composed of an output interface, an input interface, a memory, a CPU (central processing unit), etc., and detects the XY shake amount in accordance with the output from the differential amplifier 9 and calculates the shake correction amount. . A signal corresponding to the calculated amount of camera shake correction is sent to the correction driving unit 11, which drives the shake correcting units 12 and 13 through the correction driving unit 11 and displaces the image sensor 7 in a direction for reducing the camera shake. . The shake correcting means 12 is driven in a direction for correcting shake around the X axis, and the shake correcting means 13 is driven in a direction for correcting shake around the Y axis. This series of camera shake correction operations is repeatedly performed during exposure, and an image having no camera shake even when exposed in the camera shake state can be obtained from the image pickup means 14.

The vibration detectors 5 and 6 such as AD converters
The same effect can be obtained even if it is included in the arithmetic processing means 10 or provided separately. Further, the vibration detection units 5 and 6, the high-pass filter unit 8, and the differential amplification unit 9
And the arithmetic processing means 10 including the vibration detection unit constitute the vibration detection device of the present invention.

FIG. 3 is a circuit diagram of the first embodiment showing a specific circuit configuration of the vibration detection system. Since the circuit configurations for detecting the shakes around the X axis and the Y axis are the same, FIG. In the following description, only the vibration detection around one X axis will be described.

The vibration detecting system of the first embodiment includes a vibration detecting section 5 for detecting a shake around the X axis, a high pass filter section 8X for removing a drift component contained in the vibration detecting signal output from the vibration detecting section 5, Vibration detection signal and reference voltage Vref
Processing unit 10 having a vibration detection unit 20 such as a differential amplification unit 9X that differentially amplifies the vibration signal, an AD converter that detects the vibration signal output from the differential amplification unit 9X, and a switch that disconnects the transmission of the vibration detection signal. It is composed of sections SWA and SWB.

In FIG. 3, the reference voltage generator (Vre
Although f) is built in the vibration detecting unit 5, the effect is the same even if it is separately provided outside.
out is an output terminal of the vibration detection signal, Vref generates a voltage which is about ½ of the power supply voltage supplied to the vibration detection unit 5,
The high-pass filter 8X is a terminal for outputting a reference voltage for differential amplification, and the high-pass filter 8X includes a capacitor C10 and a resistor R1.
It is a known circuit composed of 0s.

The differential amplifier 9X includes a differential amplifier OP10,
A filter capacitor C that constitutes a low-pass filter together with the gain setting resistor R11, the feedback resistor R12, and the resistor R12.
The amplification factor is represented by (1 + R12 / R11) from the resistance values of the resistors R11 and R12. The vibration detection signal due to camera shake is usually an output voltage of about 1 mVpp, and if the moving range of the vibration detection unit is 3.3 Vop and the margin of the input dynamic range is 6 times, the amplification factor of the differential amplification unit 9X is set. Is about 275. Here, the power source Vc
A well-known offset adjustment circuit is configured by a variable resistor VR10 and a resistor R13 connected between c and the ground, and the offset voltage existing between the +/− input terminals of the differential amplifier OP10 is corrected. When the differential amplifier OP10 having an offset voltage of 4 mV is used, a product obtained by multiplying the offset voltage by the amplification factor is output from the differential amplifier OP10 as a difference from the reference voltage. That is, 3.3 / 2
± 0.004 × 275 = 1.65 ± 1.1V, and the output at rest is 0.55V when there is no vibration in the vibration detector 5.
It will fluctuate between ˜2.75V.

The offset adjusting circuit corrects the offset voltage and sets the stationary output to about 1.65V. In the example shown in FIG. 3, the offset adjustment circuit is composed of the variable resistor VR10 and the resistor R13, but the offset adjustment may be performed by a DA converter controlled by the arithmetic processing unit 10 or a digital potentiometer.

When the amplification factor of the differential amplifier OP10 is low,
Alternatively, the offset adjustment is unnecessary when the dynamic range of the vibration detector is wide, and performing the offset adjustment is outside the scope of the present invention. In the example shown in FIG. 3, the switch units SWA and SWB are provided at two positions in front of and behind the capacitor C10, but this is for the purpose of illustrating that position, and either one of them may be installed.

In the example shown in FIG. 3, the switch portion is a jumper terminal or a circuit board pattern, but it may be a jumper wire or a mechanical contact and is not particularly limited. During initial adjustment of these switches in the factory, offset adjustment is performed in a state where the transmission of the vibration detection signal is cut off, and the vibration detection unit 20 detects the static output when the vibration detection unit 5 does not vibrate, and a storage unit (not shown). The detection voltage is stored in. By detecting in the disconnected state, it is possible to detect the stationary output excluding the vibration factor existing in a factory or the like. The actual shake amount of camera shake can be calculated by connecting this switch at the time of factory shipment and taking the difference between the detected vibration signal and the stored static output voltage during actual use.

FIG. 4 is a circuit diagram of a second embodiment showing a concrete circuit configuration of the vibration detection system. The switch units SWA and SWB are constituted by analog switches and the opening / closing control thereof is included in the arithmetic processing means 10. The circuit configuration is performed by the control unit 21. In the following description, the same members as those described in FIG. 3 are designated by the same reference numerals,
The explanation is also omitted.

In FIG. 4, switch sections SWA and S
The WBs are provided at two positions before and after the capacitor C10, but this is to exemplify the installation position of the switch unit, and either one may be installed. In addition, switch unit SWA
Although SWB and SWB are configured by analog switches or the like, mechanical contacts such as relays may be used and are not particularly limited.

At the initial stage of the camera shake correction operation and / or during the correction operation of these switches, the vibration detection unit 20 disconnects the transmission of the vibration detection signal, and the vibration detection unit 5 outputs the static output when the vibration detection unit 5 does not vibrate. The detected voltage is detected and stored in a storage unit (not shown). By detecting in this disconnected state, it is possible to detect the output at rest without the factor of vibration applied to the camera body or the like. When vibration is detected, this switch is connected, and the actual shake amount of camera shake can be calculated by calculating the difference between the detected vibration signal and the stored static output voltage. If the switch is disconnected, the output at rest is detected, and the output voltage at rest is updated and stored periodically during the camera shake correction operation, the temperature fluctuation of the offset voltage of the differential amplifier OP10 can be excluded. Therefore, the amount of camera shake can be accurately detected even if an inexpensive differential amplifier is used.

FIG. 5 is a circuit diagram of a third embodiment showing a specific circuit configuration of the vibration detection system. The high-pass filter 8X and the differential amplifier 9X shown in FIGS. 3 and 4 are connected in two stages in series. Showing the circuit configuration of the first high-pass filter 8X1
Is from the capacitor C10 and the resistor R10, and the second high-pass filter 8X2 is from the capacitor C20 and the resistor R10.
This is a known circuit composed of 20. The first differential amplifier 9X1 includes a differential amplifier OP10 and a gain setting resistor R1.
1, a feedback resistor R12, and a filter capacitor C11 that forms a low-pass filter together with the resistor R12. Similarly, the second differential amplifier 9X2 includes a differential amplifier OP2.
0, a gain setting resistor R21, a feedback resistor R22, and a filter capacitor C21 that forms a low pass filter together with the resistor R22. Switches SW1 and S
W2 is controlled to be opened / closed by a control unit included in the arithmetic processing unit 10, and constitutes a starting circuit unit. The switches SW1 and SW2 are for closing the circuit shown in FIG. 5 at the moment when the power is turned on, and by rapidly charging the high-pass filter circuit 8X, the start-up delay due to the long time constant of the high-pass filter circuit is compensated. is there. Switch part S
WA has the same function as the switch units SWA and SWB in FIG.

In FIG. 5, the amplification rate of the first differential amplification section 9X1 is set to the amplification rate of the second differential amplification section 9X2. For example, in the case of the total amplification rate 275, the first differential amplification section 9X1 is set.
Is set to 55 and the amplification rate of the second differential amplifier 9X2 is set to 5. In this case, the offset voltage 4 mV of the differential amplifier OP10 multiplied by the amplification factor (55 times) is output from the differential amplifier OP10 as a difference from the reference voltage. That is, 3.3 / 2 ± 0.004 × 55 = 1.6
It becomes 5 ± 0.22V, and the output at rest when the vibration detector 5 has no vibration fluctuates between 1.43V and 1.87V.

This static output variation 1.43V to 1.87
The first vibration signal associated with camera shake is superimposed on V, but if the vibration detection signal associated with normal camera shake is 1 mVpp, then
The vibration signal is 55 times that, that is, 55 mVpp,
Even if a considerable margin is taken into consideration, the output of the differential amplifier OP10 is not saturated, and the output fluctuation at the time of static is cut off the DC component by the second high-pass filter 8X2 at the next stage. Therefore, the offset adjustment circuit shown in FIG. Is the first in FIG.
It can be deleted from the differential amplifier 9X1.

Similarly, in the second differential amplifier 9X2, the offset voltage 4 mV multiplied by the amplification factor (5 times) is output from the differential amplifier OP20 as a difference from the reference voltage. That is, 3.3 / 2 ± 0.004 × 5 = 1.6
It becomes 5 ± 0.02V, and the output at rest when the vibration detecting unit 5 does not vibrate fluctuates between 1.63V and 1.67V. This output fluctuation at rest 1.63V to 1.67
As for V, the second vibration signal due to camera shake is 275 mVpp, which does not saturate the output of the differential amplifier OP20 in the same manner as described above. Therefore, the second differential amplifier 9X2 is also used.
Therefore, the offset adjustment circuit can be deleted. The method of using the switch unit SWA to detect the stationary output when the vibration detection unit 5 has no vibration in the vibration detection unit 20 is the same as the example shown in FIG.

The switch section SWA shown in FIG. 5 has the same description as the analog switch configuration shown in FIG. 4, but may have the same configuration as the switch section in the example shown in FIG.

FIG. 6 is a circuit diagram of a fourth embodiment showing a specific circuit configuration of the vibration detection system. In the fourth embodiment, the switch section SWA shown in FIG. 5 is deleted and the reference voltage is calculated. 6 shows a circuit configuration for detection by a vibration detection unit 20 such as an AD converter included in the processing means 10. In the example shown in FIG. 6, the reference voltage is output at the stationary state when the vibration detection unit 5 does not vibrate in the vibration detection unit. Treat as. That is, the camera shake correction operation is performed based on the difference between the detected reference voltage and the second vibration signal. This is because the offset voltage included in the second vibration signal is 20 mV and the shake component of the second vibration signal is 275 mVpp, as described above.
This is because the offset voltage included in the vibration signal has a negligible level.

If a changeover switch unit is provided in front of the vibration detection unit 20 and the second vibration signal and the reference voltage are time-divisionally switched for reading and detection, an AD converter or the like can be saved.

[0033]

As described above, according to the present invention,
It is possible to provide a vibration detection device capable of accurately detecting the output at rest in a state where there is no vibration in the vibration detection unit by the vibration detection unit with a simple circuit configuration.

[Brief description of drawings]

FIG. 1 is an external perspective view of a photographing device for explaining an embodiment of the invention.

FIG. 2 is an explanatory diagram showing a main part of a configuration for realizing a basic shake correction method in an image capturing apparatus.

FIG. 3 is a circuit diagram of a first embodiment of the present invention showing a specific circuit configuration of a vibration detection system.

FIG. 4 is a circuit diagram of a second embodiment of the present invention showing a specific circuit configuration of a vibration detection system.

FIG. 5 is a circuit diagram of a third embodiment of the present invention showing a specific circuit configuration of a vibration detection system.

FIG. 6 is a circuit diagram of a fourth embodiment of the present invention showing a specific circuit configuration of a vibration detection system.

[Explanation of symbols] 5 Vibration detector (around X axis) 6 Vibration detector (Y axis) 7 Image sensor 8 High-pass filter section 9 Differential amplifier 10 arithmetic processing means 11 Correction driving means 12 Shake correction means (around X axis) 13 Shake correction means (around Y axis) 14 Imaging means 20 Vibration detector 21 Control unit SWA, SWB switch section

Claims (6)

[Claims] 1. A vibration detection unit for detecting vibration and outputting a vibration detection signal, a reference voltage generation unit for generating a reference voltage supplied to the vibration detection unit, and an influence of drift of a static detection output of the vibration detection signal. A high-pass filter section for blocking the DC component of the vibration detection signal to remove the vibration detection signal, and a differential amplification section for outputting the vibration signal by differentially amplifying the vibration detection signal and the reference voltage that have passed through the high-pass filter section. A vibration detecting device for detecting a vibration signal, the vibration detecting device comprising a switch part for cutting off the transmission of the vibration detecting signal before or after the capacitor forming the high-pass filter part, and the vibration in the cut state. A vibration detecting device characterized by detecting an output at rest when there is no vibration in the detecting section. 2. The vibration detecting device according to claim 1, wherein the switch unit is provided in a stage before a resistor that constitutes the high pass filter unit and in a stage after the capacitor that constitutes the high pass filter unit. 3. A vibration detection unit for detecting vibration and outputting a vibration detection signal, a reference voltage generation unit for generating a reference voltage supplied to the vibration detection unit, and an influence of drift of the static detection output of the vibration detection signal. A first high-pass filter section for blocking a direct current component of the vibration detection signal for removing the noise, and a first high-pass filter section for outputting the vibration signal by differentially amplifying the vibration detection signal and the reference voltage which have passed through the first high-pass filter section. A differential amplification section, a second high-pass filter section that blocks the DC component of the vibration signal, and a second vibration signal is output by differentially amplifying the vibration signal and the reference voltage that have passed through the second high-pass filter section. In a vibration detection device including a second differential amplification section and a vibration detection section for detecting a second vibration signal, a vibration detection signal is transmitted after a capacitor that constitutes the second high-pass filter section. A vibration detection device comprising a switch unit for disconnecting the device, and detecting a stationary output when there is no vibration in the vibration detection unit in the disconnected state. 4. A switch unit for disconnecting transmission of a vibration detection signal in a front stage or a rear stage of the capacitor which constitutes the second high pass filter unit, and a time constant of the first high pass filter unit and the second high pass filter unit. 4. The vibration detecting device according to claim 3, further comprising a starting circuit unit for variably controlling the vibration. 5. The vibration detection device according to claim 3, wherein the reference voltage is output at rest when the vibration detection unit has no vibration. 6. The vibration detection device according to claim 1, further comprising a control unit that controls opening / closing of the switch unit.