JP2012123149A - Optical equipment having blur correction function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve blur prevention function by improving resolution of a position detection system for detecting a drive position of a blur prevention unit or a blur detection system.SOLUTION: Provided are: blur detection means for detecting blur; blur prevention means 109 operating to prevent image blur; driving means for driving the blur prevention means based on output from the blur detection means; means 117 for adjusting offset of position detection means and including first position detection means and second position detection means for detecting a drive position of the blur prevention means; and amplification means 112 for amplifying output of the first position detection means. The second position detection means detects a value of the output amplified of the first position detection means, and offset of the second position detection means is adjusted based on the output of the first position detection means.

Description

  The present invention relates to position detection of an optical apparatus having a shake correction function.

  Some optical devices are equipped with an image stabilization unit that suppresses image blur by displacing an optical element such as a lens in accordance with the shake of the optical device. For such an image stabilization unit, a signal indicating the drive amount of the image stabilization unit generated based on the amount of vibration detected by the vibration sensor and a position detection system for detecting the drive position of the image stabilization unit are provided. In many cases, feedback control using a position signal is performed. As the sensor unit of the position detection system, an optical sensor such as a photo interrupter, a magnetic sensor combining a magnetic body and a Hall element, or the like is used.

  The position detection system performs position detection with a predetermined resolution over the entire driving range of the image stabilization unit. For example, the position signal output from the sensor unit of the position detection system is processed by the control circuit as a digital position signal having a resolution of a predetermined number of bits via the A / D converter.

  In recent years, with the rapid increase in image quality and magnification of digital video cameras and digital still cameras, it is necessary to increase the detection accuracy (resolution) of the vibration-proof unit drive position against camera shake and perform more precise vibration-proof drive control. There is. However, if position detection is performed using a detection device having a high resolution detection accuracy in order to increase the resolution, the detection device becomes expensive, which is not preferable.

  In order to solve the above-described problem, Patent Document 1 uses two position detection systems to amplify the position detection signal in the camera shake correction range at the center of the drive range and increase the position detection resolution, thereby detecting accuracy. A technique for improving the above is disclosed. FIG. 6 shows the method. 601 is a diagram in which the entire position of the drive signal is acquired by 10-bit A / D in the first position detection system, and a detection range from −1 deg to 1 deg can be acquired by 1024 divisions. 602 is a diagram in which a signal obtained by amplifying the central portion of the first detection system by a factor of 4 in the second detection system is acquired by A / D at 10 bits, and the range from −0.25 deg to 0.25 deg is 1024. Can be obtained in divisions. The position P61 acquired by the first position detection system becomes P62 in the second position detection system, and a value having a higher resolution than P61 can be acquired.

JP 2007-147669 A

  However, in the technique disclosed in Patent Document 1, the reference position (offset) of the second position detection system having a high detection resolution is the reference position of the first position detection system, and an accurate vibration isolation range is provided. It will be limited. For example, in FIG. 4, the detection range of the second detection system is limited to −0.25 deg to 0.25 deg. If this range is exceeded, normal resolution is obtained.

  FIG. 7 is a diagram showing the range of the shake correction amount in the difference in amplification factor. The horizontal axis in FIG. 7 indicates the shake correction amount from the reference position (only positive values are shown), and the vertical axis indicates the position detection voltage. 701 indicates that the detection range of the second detection system when the amplification factor is 4 times is 0 deg to 0.25 deg. Similarly, 702 indicates that when the amplification factor is 2 times, 0 deg to 0.5 deg. When the amplification factor is 1, it indicates that it is 0 deg to 1 deg.

  As can be seen from this figure, the higher the amplification factor and the higher the resolution, the narrower the position detection signal range after amplification becomes compared to the entire position detection range. The detection range has the following relationship.

Detection range after amplification = total detection range x (1 / amplification rate)
The present invention does not make the reference position of the second detection system equal to the reference position of the first detection system, but makes it possible to move the high-resolution range by making it variable and widen the accurate vibration-proof range. It is an object. In addition, by making the high-resolution part variable, it is possible to obtain an accurate anti-vibration effect without worrying about the range even if the resolution magnification is further increased and the accurate detection range becomes narrow. It is aimed.

The first solving means includes shake detecting means for detecting shake,
Anti-vibration means that operates to suppress image blur;
Drive means for driving the image stabilization means based on the output from the shake detection means;
Position detecting means for detecting a driving position of the vibration isolating means;
Means for adjusting the offset of the position detection means;
The position detection means includes first position detection means having a first detection resolution;
In the optical apparatus constituted by the second position detection means having a different resolution from the first position detection means,
The offset of the second position detecting means is adjusted based on the output of the first position detecting means.

The second solution means is a shake detection means for detecting shake,
Anti-vibration means that operates to suppress image blur;
Drive means for driving the image stabilization means based on the output from the shake detection means;
Position detecting means for detecting a driving position of the vibration isolating means;
Means for adjusting the offset of the shake detection means;
The shake detection means includes a first shake detection means having a first detection resolution;
In the optical apparatus constituted by the second shake detection means having a resolution different from that of the first shake detection means,
The offset of the second shake detection means is adjusted based on the output of the first shake detection means.

  According to the present invention, by making the reference position of the high resolution detector variable, it is possible to perform shake correction with high accuracy in a wider range.

The figure which shows the structure which can apply Example 1 of this invention. The figure which calculates | requires the offset position of a 2nd detection system based on the detection position of a 1st detection system. 6 is a flowchart illustrating a camera shake correction operation in the embodiment. The figure which shows the structure which can apply Example 2 of this invention. The figure which shows the structure which can apply Example 3 of this invention. The figure which amplified the signal by making the reference value of the signal of the 1st detection system into the reference value of the signal of the 2nd detection system. The figure which shows the relationship between an amplification factor and shake correction amount.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[Example 1]
FIG. 1 shows a system configuration for increasing the resolution of a position detection system that is Embodiment 1 of the present invention.

  Reference numeral 101 denotes a gyro sensor (angular velocity sensor) as a shake detecting means, which outputs a signal corresponding to the angular velocity of the binocular shake. An angular velocity sensor is a sensor that applies the Coriolis principle. However, a sensor other than the gyro sensor may be used as long as it can output a signal corresponding to the shake.

  A microcomputer 102 includes a 10-bit A / D converter (103, 113, 114) and an 8-bit D / A converter 118, performs position calculation from a gyro signal processing and a position detection system, and drives an image stabilization unit. Feedback control.

  Reference numeral 103 denotes an A / D converter that digitizes a signal from the gyro sensor 101 in 10 bits.

  A gyro signal processing unit 104 acquires shake amount data from the gyro sensor 101 (A / D converter 103), and converts the angular velocity data into angular displacement data indicating the shake amount by performing an integration operation. This is output to the adding unit 105.

  The adding unit 105 subtracts the position data output from the position calculation 2 of 116 described later from the angular displacement data output from 104 to obtain a control deviation.

  A drive signal generation unit 106 performs phase compensation calculation for stabilizing the feedback control system and loop gain calculation for improving the control performance, and generates drive data for driving the image stabilization unit 109 described later. Generate.

  Reference numeral 107 denotes a drive circuit, which receives drive data from the drive signal generation unit 106 and drives the vibration isolation actuator 108. The anti-vibration circuit 107 is configured by a PWM drive driver or the like having a transistor H-bridge configuration.

  Reference numeral 108 denotes an anti-vibration actuator that drives the anti-vibration unit 109. The type of the vibration-proof actuator 108 is not limited. For example, an electromagnetic actuator such as a voice coil motor can be used. The drive direction of the vibration isolation unit 109 is a perpendicular biaxial direction (pitch direction and yaw direction), and one vibration isolation actuator is required for each drive direction, but only one is shown in the figure. ing.

  Reference numeral 109 denotes an anti-vibration unit, which may be a shift unit that performs anti-vibration by shifting the lens in the pitch direction and yaw direction, a variable apex angle prism (VAP), or the like. The image stabilization unit 109 is driven by the actuator 108, and the vibration is suppressed by being appropriately driven according to the hand shake signal.

  Reference numeral 110 denotes an encoder, which constitutes a sensor for detecting the drive position of the image stabilization unit 109. For example, a magnetic sensor and a Hall element are combined to form a magnetic detection sensor or the like. In addition, since the drive position detection of the image stabilization unit 109 is performed in each of the pitch direction and the yaw direction, one encoder is required for each drive direction, but only one is shown in FIG.

  Reference numeral 111 denotes a position detection circuit which receives a signal from the encoder 110 and receives a voltage value centered on a reference voltage within a voltage range (for example, 0 V to 3 V) assigned to the driveable range of the image stabilization unit 109 ( For example, a position detection signal having 1.5V) is output. The reference voltage is adjusted so that the optical axis of the image stabilization unit 109 coincides with the optical axis of the lens when the image stabilization function is not activated.

  Reference numeral 112 denotes a position detection amplifier, which amplifies a position detection signal obtained from the position detection circuit 111 of the image stabilization unit 109 with a predetermined amplification factor using a signal from an offset adjustment unit 117 described later as a reference position. The position detection amplifier is configured using, for example, an operational amplifier and a resistor. By amplifying the position detection signal, the position detection resolution of the image stabilization unit 109 can be increased. For example, when the amplifier 112 has a gain of 4 times, it corresponds to the fact that a resolution of 2 bits is substantially added in digital signal conversion. In addition, when the amplification factor is 16 times, this is equivalent to adding a resolution of 4 bits substantially.

  Reference numerals 113 and 114 denote first and second A / D converters for position detection. The first A / D converter 113 digitizes the entire waveform of the position detection signal from the position detection circuit 111 with a 10-bit resolution (first resolution). Further, the second A / D converter 114 digitizes the entire enlarged waveform of the position detection signal by the amplifier 112 with a resolution of 10 bits, like the first A / D converter 113. In this embodiment, the same first and second A / D converters 113 and 114 are used, and the position detection signal amplified by the amplifier 112 is input to the second A / D converter 114. Yes. Thereby, it is possible to suppress an increase in cost while increasing the resolution of the digital position detection signal output from the second A / D converter 114.

  Here, the encoder 110, the position detection circuit 111, and the first A / D converter 113 constitute a first position detection system. The encoder 110, the position detection circuit 111, the amplifier 112, and the second A / D converter 114 constitute a second position detection system.

  Reference numeral 115 denotes a first position calculation unit that performs predetermined calculation processing based on drive data of the image stabilization unit 109 having a normal resolution obtained from the first A / D converter 113. Reference numeral 116 denotes a second position calculation unit that performs predetermined calculation processing based on drive data of the high-resolution image stabilization unit 109 obtained from the second A / D converter 114. Position data suitable for subtraction from the angular displacement data output from the gyro signal processing unit 104 is generated by the predetermined arithmetic processing described here.

  Reference numeral 117 denotes an offset adjustment unit that performs offset adjustment of the second position detection system based on the signal of the first position detection system obtained from the position calculation 1 of 115 (FIG. 2). Specifically, the first position detection range is divided into several regions, and the region where the detected value is located is examined. In each region, the center of the region is determined as the offset position of the second detection system. In FIG. 2, the amplification factor to the second detection system is four times, and the detection range of the first detection system may be roughly divided into four based on the amplification factor, but here the second detection system In the example shown in FIG. In this example, the number of divisions is 5. However, any number of divisions may be used. In FIG. 2, the detected value P21 is in the region from 0.2 deg to 0.6 deg, and the offset position is 0.4 deg. If the entire position detection range is -1 deg to 1 deg and the voltage detected by the position detection circuit 111 is 0 V to 3 V, the reference voltage of the first detection system is 1.5 V at 0 deg. Since it is 0.4 deg, it becomes 2.1 V (1.5 V + 1.5 V × 0.4 deg). The offset adjustment unit 117 outputs data to the D / A converter 118 so that the second detection system reference voltage is output.

  Reference numeral 118 denotes an 8-bit D / A converter that inputs the reference position obtained by the offset adjustment 117 to the amplifier 112 as a voltage. In the present embodiment, the D / A converter is illustrated as being built in the microcomputer 102, but an external D / A converter may be used.

  Although not shown, the optical apparatus of the present embodiment is provided with a vibration isolating switch for the photographer to select whether or not the vibration isolating unit 109 performs the vibration isolating operation. When the image stabilization switch is on, an image stabilization operation is performed, and when the image stabilization switch is off, the image stabilization operation is not performed.

  Next, the operation of the microcomputer 102 will be described using the flowchart of FIG.

  In step 301 (S301 in the drawing), when the above-described image stabilization switch is turned on, the microcomputer starts the process of image stabilization operation. In step 302, the angular velocity data from the gyro sensor 101 is taken in via the A / D converter 103.

  In step 303, the acquired angular velocity data is converted into angular displacement data by the gyro signal processing unit 104.

  In step 304, the position data of the image stabilization unit 109 is fetched from the first A / D converter 113, and the position calculation is performed by the position calculation unit 1 115.

  In step 305, the reference position of the second position detection system is obtained based on the position data acquired in step 304. In step 306, the obtained reference position is converted into data that can be input to the D / A converter 118, and a voltage is output from the D / A converter 118.

  In step 307, the amplified position signal of the image stabilization unit 109 is fetched from the second A / D converter 114, and the position calculation is performed by the position calculation unit 2 116.

  In step 308, the angular displacement data obtained from the gyro sensor 101 and the position obtained from the image stabilization unit 109 are subtracted and transmitted to the drive circuit 107 as appropriate drive data via the drive signal generation unit 106. The drive circuit 107 drives the image stabilization unit 109 based on the received drive data, thereby performing shake correction feedback control.

  In step 309, it is determined whether or not the camera shake switch is off. If it is on, the process returns to step 302. If it is off, the image stabilization operation is terminated.

  As described above, in this embodiment, the first position detection system grasps the entire position, and the second position detection system amplifies the signal so as to follow the signal of the first position detection system, thereby increasing the resolution. Thus, accurate position detection can be performed in any range, and a more anti-vibration effect can be obtained.

[Example 2]
FIG. 4 shows a system configuration for increasing the resolution of a shake detection system that is Embodiment 2 of the present invention.

  In the first embodiment, the method of increasing the resolution by amplifying the signal of one of the two detection systems and increasing the resolution has been described in this embodiment. However, in this embodiment, the signal of one of the detection systems is amplified. A method for increasing the resolution will be described. For this reason, the second position detection system in the first embodiment is not provided.

  In FIG. 4, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG.

  Reference numeral 401 denotes a shake detection amplifier that amplifies a shake detection signal obtained from the gyro sensor 101 with a signal from an offset adjustment unit 404 described later as a reference position at a predetermined amplification factor. The shake detection amplifier is configured using, for example, an operational amplifier and a resistor. By amplifying the shake detection signal, the shake detection resolution of the gyro sensor 101 can be increased. For example, when the amplifier 401 has a gain of 4 times, this corresponds to the fact that a resolution of 2 bits is substantially added in digital signal conversion. In addition, when the amplification factor is 16 times, this is equivalent to adding a resolution of 4 bits substantially.

  Reference numerals 402 and 403 denote first and second A / D converters in shake detection. The first A / D converter 402 digitizes the entire waveform of the shake detection signal from the gyro sensor 101 with a 10-bit resolution (first resolution). In addition, the second A / D converter 403 digitizes the entire enlarged waveform of the shake detection signal from the amplifier 401 with a resolution of 10 bits, like the first A / D converter 402. In this embodiment, the same first and second A / D converters 402 and 403 are used, and the position detection signal amplified by the amplifier 401 is input to the second A / D converter 403. Yes. Thereby, it is possible to suppress an increase in cost while increasing the resolution of the digital shake detection signal output from the second A / D converter 403.

  Here, the first A / D converter 402 constitutes a first shake detection system. The amplifier 401 and the second A / D converter 403 constitute a second shake detection system.

  Reference numeral 404 denotes an offset adjustment unit that performs offset adjustment of the second shake detection system based on the shake detection system signal obtained from the gyro sensor 101. Since the offset adjustment method is the same as that of the first embodiment (FIG. 2), a description thereof will be omitted. The offset adjustment unit 404 outputs data to the D / A converter 405 so that the second detection system reference voltage is output.

  Reference numeral 405 denotes an 8-bit D / A converter that inputs the reference position obtained by the offset adjustment 404 to the amplifier 401 as a voltage. In the present embodiment, the D / A converter is illustrated as being built in the microcomputer 102, but an external D / A converter may be used.

  Reference numeral 406 denotes an adder, which subtracts the position data output from the position calculation 1 reading the entire area in the first embodiment from the angular displacement data output from the gyro signal processing unit 104 to obtain a control deviation.

  In this way, in this embodiment, the first shake detection system grasps the entire position, and the second shake detection system amplifies the signal to follow the signal of the first shake detection system, thereby increasing the resolution. Thus, accurate shake detection can be performed in any range, and a more anti-vibration effect can be obtained.

[Example 3]
In the first embodiment, the resolution of the position detection system is increased. In the second embodiment, the resolution of the shake detection system is increased. In the third embodiment, the resolution of the position detection system and the shake detection system are increased. Is shown in FIG.

  5, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1, and the same components as those in the second embodiment (FIG. 4) are denoted by the same reference numerals as those in FIG. Omitted.

  As described above, in this embodiment, the first position detection system and the shake detection system grasp the entire position, and the second position detection system and the shake detection system follow the signals of the first position detection system and the shake detection system. Thus, by amplifying the signal and increasing the resolution, accurate position detection and shake detection can be performed in any range, and a more anti-vibration effect can be obtained.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

DESCRIPTION OF SYMBOLS 101 Gyro sensor 109 Anti-vibration unit 112 Position signal amplifier 113, 114 A / D converter 117 Position detection system offset adjustment part 401 Shake signal amplifier 404 Position detection system offset adjustment part

Claims (2)

Shake detection means for detecting shake;
Anti-vibration means that operates to suppress image blur;
Drive means for driving the image stabilization means based on the output from the shake detection means;
Position detecting means for detecting a driving position of the vibration isolating means;
Means for adjusting the offset of the position detection means;
The position detection means includes first position detection means having a first detection resolution;
The second position detection means having a different resolution from the first position detection means,
An optical apparatus characterized in that an offset of the second position detecting means is adjusted based on an output of the first position detecting means. Shake detection means for detecting shake;
Anti-vibration means that operates to suppress image blur;
Drive means for driving the image stabilization means based on the output from the shake detection means;
Position detecting means for detecting a driving position of the vibration isolating means;
Means for adjusting the offset of the shake detection means;
The shake detection means includes a first shake detection means having a first detection resolution;
The first shake detection means comprises a second shake detection means having a different resolution,
An optical apparatus characterized in that an offset of the second shake detection means is adjusted based on an output of the first shake detection means.