JP2013156442A - Lens device, imaging apparatus and absolute position detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens device that can detect the absolute position of a movable optical element with high accuracy.SOLUTION: A lens device 2 includes: a focus lens 21, a zoom lens 22, and a diaphragm device 23 which are a movable optical element; a sensor unit 40 that increases the peak value of an output signal according to movement of the movable optical element in one direction; a sensor unit 50 that decreases the peak value of an output signal according to movement of the movable optical element in the one direction; and a lens control unit 20 for detecting the absolute position of the movable optical element on the basis of the results of calculation using the peak value of an output signal of the sensor unit 40 and the peak value of an output signal of the sensor unit 50.

Description

  The present invention relates to a lens device, an imaging device, and an absolute position detection method.

  In recent years, televisions and monitors have been increased in screen size and resolution, and there has been an increasing demand for higher image quality for projected images. In order to meet this demand for higher image quality, a broadcast zoom lens is equipped with an encoder that can detect a position with high accuracy, thereby improving the performance of lens control.

  Encoders are roughly classified into incremental type encoders and absolute type encoders. The detection signal of the incremental encoder includes an A phase signal, a B phase signal, and a Z phase signal. The A phase signal and the B phase signal have a predetermined difference in waveform phase, and the moving direction of the zoom lens can be detected by detecting the phase relationship of the output waveform. The Z-phase signal is a signal indicating the reference position of the zoom lens.

  The incremental encoder detects the zoom lens position with the number of A-phase or B-phase pulses counted from the reference position. The incremental type encoder has a relatively simple structure and is inexpensive, but cannot accurately know the lens position after the power of the lens apparatus is turned on until the encoder detects the reference position. In particular, when performing a zoom operation manually, it may take time to detect the reference position, and during that time, image stabilization and optical correction by the camera cannot be performed correctly.

  Patent Documents 1 and 2 disclose a method for obtaining an absolute position of a movable part without detecting a reference position.

  Patent Document 1 uses a sensor unit in which the peak value of a detection signal increases or decreases according to the amount of movement of the lens, and data that associates the peak value of the detection signal with the position of the lens. An imaging apparatus that detects the absolute position of a lens from a peak value first detected by a sensor unit and the above data is disclosed.

  Patent Document 2 uses a sensor unit in which a peak value of a detection signal continuously changes in accordance with the amount of movement of the movable unit, and data in which the peak value of the detection signal is associated with the position of the movable unit. An apparatus for detecting an absolute position of a movable part from a peak value detected by a part and the above data is disclosed.

JP 2009-169202 A JP 2004-205257 A

  However, in the absolute position detection methods described in Patent Documents 1 and 2, if the output of the sensor unit changes due to deterioration over time, the detected absolute position is deviated, and the absolute position detection accuracy decreases. .

  The present invention has been made in view of the above circumstances, and provides a lens device that can detect the absolute position of a movable optical element with high accuracy, an imaging device including the lens device, and an absolute position detection method. With the goal.

  The lens device of the present invention includes a movable optical element, a first sensor unit in which a peak value of an output signal increases in accordance with movement of the movable optical element in one direction, and the movable optical element in the one direction. A second sensor unit that reduces the peak value of the output signal in accordance with movement, a peak value of the output signal of the first sensor unit, and a peak value of the output signal of the second sensor unit. And an absolute position detector that detects the absolute position of the movable optical element based on the result.

  The imaging device of the present invention includes the lens device and an imaging device body that captures an optical image collected by the lens device.

  The absolute position detection method of the present invention includes an output signal of a first sensor unit in which a peak value of an output signal increases in accordance with movement of a movable optical element in one direction, and movement of the movable optical element in the one direction. The absolute position of the movable optical element is detected on the basis of the result of calculation using the output signal of the second sensor unit in which the peak value of the output signal decreases in response.

  ADVANTAGE OF THE INVENTION According to this invention, the lens apparatus which can detect the absolute position of a movable optical element with high precision, an imaging device provided with this lens apparatus, and an absolute position detection method can be provided.

1 is an external view of an imaging apparatus equipped with a lens apparatus according to an embodiment of the present invention. The block diagram which shows the internal structure of the lens apparatus 2 shown in FIG. The figure which shows the structure of the zoom position detection part 25 shown in FIG. The figure which shows the structure of the slit part shown in FIG. The figure which shows the signal waveform output from the sensor parts 40 and 50 shown in FIG. The figure which shows the signal waveform output from the comparator shown in FIG. The figure which showed the change of the peak value of the A phase signal output from the A / D converter 80 shown in FIG. 3, and the peak value of the B phase signal output from the A / D converter 81 shown in FIG. In FIG. 7, the figure which shows the result of subtracting the peak value of the B phase signal from the peak value of the A phase signal corresponding to the same opening No. The figure for demonstrating operation | movement of the lens apparatus 2 The figure for demonstrating operation | movement of the lens apparatus 2 The figure which shows the modification of the sensor parts 40 and 50 shown in FIG.

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

  FIG. 1 is an external view of an imaging apparatus equipped with a lens apparatus 2 according to an embodiment of the present invention. A lens device 2 is attached to the front portion of the imaging device main body 1.

  The lens device 2 includes a cylindrical housing 10 such as a cylindrical shape. The housing 10 includes a photographing lens such as a zoom lens and a focus lens, and a diaphragm device that can adjust the aperture. A mount 3 is provided at the base of the housing 10 of the lens device 2. The lens device 2 is fixed to the imaging device main body 1 by detachably attaching the connecting portion of the mount portion 3 to a lens mounting portion provided at the front portion of the imaging device main body 1.

  The imaging device main body 1 is provided with an imaging element on the optical axis of the lens device 2 in a state where the lens device 2 is mounted. And the optical image condensed with the lens apparatus 2 is imaged with this image pick-up element. The output signal of the imaging device is processed by an image processing unit built in the imaging apparatus main body 1 to generate various image data.

  The photographer 5 holds the imaging device main body 1 on the right shoulder and looks into the viewfinder device 6 with the right eye, for example. Then, the photographer 5 takes a picture of the subject while holding the holding unit of the lens device 2 with the right hand 7 and fixing the imaging device.

  A focus ring 8 that adjusts the focal position of the focus lens is provided on the front end side (subject side) of the lens apparatus 2 so as to be rotatable around the lens apparatus 2. The focus position can be adjusted by rotating the focus ring 8 by an arbitrary angle by the photographer 5 by hand.

  A zoom ring 9 for adjusting the zoom position of the zoom lens is provided at an intermediate portion of the lens device 2 so as to be rotatable around the outer periphery of the lens device 2. The zoom magnification 9 can be adjusted by rotating the zoom ring 9 by an arbitrary angle by the photographer 5 by hand.

  The lens device 2 is provided with an iris ring 11 for adjusting the opening amount of the aperture device on the side of the imaging device main body 1 of the zoom ring 9. The iris ring 11 is provided so as to be rotatable around the outer periphery of the lens device 2.

  FIG. 2 is a block diagram showing an internal configuration of the lens apparatus 2 shown in FIG.

  The lens device 2 includes a photographing optical system including a zoom lens 21 that can move along the optical axis K, a focus lens 22 that can move along the optical axis K, and a diaphragm device 23.

  The lens device 2 further includes a focus drive unit 27 that drives the focus lens 21, a zoom drive unit 28 that drives the zoom lens 22, an aperture drive unit 29 that drives the aperture device 23, a focus drive unit 27, and a zoom drive. And a lens control unit 20 for controlling the diaphragm drive unit 29. The focus drive unit 27, zoom drive unit 28, and aperture drive unit 29 control the position of the focus lens 21, the position of the zoom lens 22, and the aperture amount of the aperture device 23 based on commands from the lens control unit 20, respectively. To do.

  Furthermore, the lens device 2 includes a focus position detection unit 24 that detects the position of the focus lens 21 together with the lens control unit 20, a zoom position detection unit 25 that detects the position of the zoom lens 22 together with the lens control unit 20, and a lens control unit. 20 and an aperture position detector 26 that detects the position (opening amount) of the aperture spring of the aperture device 23.

  FIG. 3 is a diagram showing the configuration of the zoom position detection unit 25 and the lens control unit 20 shown in FIG.

  The zoom position detection unit 25 and the lens control unit 20 have the same configuration as that of the incremental encoder except for the A / D converters 80 and 81.

  The zoom position detection unit 25 includes a sensor unit 30 that outputs a Z-phase signal, a sensor unit 40 that outputs an A-phase signal, a sensor unit 50 that outputs a B-phase signal, and comparators 60, 61, and 62. , A counter 70 and A / D converters 80 and 81.

  The sensor unit 30 includes a light emitting diode 31 that is a light emitting element, a photodiode 33 that is a light receiving element, and a slit portion 32 that is disposed between the light emitting diode 31 and the photodiode 33.

  The sensor unit 40 includes a light emitting diode 41 that is a light emitting element, a photodiode 43 that is a light receiving element, and a slit portion 42 that is disposed between the light emitting diode 41 and the photodiode 43.

  The sensor unit 50 includes a light emitting diode 51 that is a light emitting element, a photodiode 53 that is a light receiving element, and a slit portion 52 that is disposed between the light emitting diode 51 and the photodiode 53.

  Each of the slit portions 32, 42, and 52 has a shape as shown in FIG. 4, and has a configuration in which an opening K is formed in the light shielding plate I that does not transmit light and that is long in the horizontal direction.

  The slit portion 32 is provided with only one opening K at the left end portion of the light shielding plate I.

  The slit portion 42 is formed by arranging a plurality of (13 in the illustrated example) openings K in the light shielding plate I in the horizontal direction at equal intervals. The plurality of openings K formed in the slit part 42 have the same horizontal width (horizontal width), but the vertical width (vertical width) increases from the left end to the right end.

  The slit part 52 inverts the slit part 42 horizontally in the horizontal direction, and further shifts the position of the opening K to the right in the horizontal direction with respect to each opening K of the slit part 42 by 1/2 of the lateral width of each opening K. It is a thing. The opening K that is nth (n is 1 to 13) from the left end in the slit 52 forms a pair with the nth opening K from the left end in the slit 42.

  In the sensor units 30, 40, and 50, the light emitting element, the light receiving element, and the slit part are relatively movable in accordance with the movement of the zoom lens 22. The light emitting element and the light receiving element may be fixed to the housing 10 of the lens device 2 so that the slit portion moves according to the movement of the zoom lens 22, or the slit portion may be fixed to the housing 10 of the lens device 2. Then, the light emitting element and the light receiving element may be moved in accordance with the movement of the zoom lens 22.

  In FIG. 4, when the zoom lens 22 is at the end (for example, the wide end) in the movable range, the light emitting element and the light receiving element of each sensor unit are perpendicular to the paper surface across the slit portion at the position indicated by the broken line in the figure. Are arranged side by side. As the zoom lens 22 moves from the wide end to the tele end side, the positions of the light emitting elements and the light receiving elements of each sensor unit shift to the right. When the zoom lens 22 is at the telephoto end, the light emitting element and the light receiving element of each sensor unit are disposed at a position indicated by a one-dot chain line in FIG.

  As described above, when the zoom lens 22 moves, the positions of the light-emitting elements and the light-receiving elements of the sensor units with respect to the slits also change. Therefore, the position of the opening K in each of the slits 42 and 52 is 1 Corresponds to one-to-one.

  FIG. 5 shows the A phase signal waveform output from the sensor unit 40 and the B phase signal waveform output from the sensor unit 50.

  As shown in the upper part of FIG. 5, the sensor unit 40 outputs an A-phase signal waveform whose peak value (amplitude value) increases in accordance with the movement of the zoom lens 22 from one end to the other end in the movable range. As shown in the lower part of FIG. 5, the sensor unit 50 outputs a B-phase signal waveform in which the peak value (amplitude value) decreases as the zoom lens 22 moves from one end to the other end in the movable range. Further, the B phase signal waveform is 90 degrees out of phase with respect to the A phase signal.

  The comparator 60 compares the output signal of the photodiode 33 with the reference voltage. When the output signal of the photodiode 33 is larger than the reference voltage, the comparator 60 becomes high level, and when the output signal of the photodiode 33 is smaller than the reference voltage, the comparator 60 becomes low. Outputs a rectangular pulse that is level. 6 shows a signal waveform output from the comparator 60 when the zoom lens 22 moves from one end to the other end. When the output of the comparator 60 becomes high level, the lens control unit 20 detects that the zoom lens 22 is at the reference position.

  The comparator 61 compares the output signal of the photodiode 43 with a reference voltage. When the output signal of the photodiode 43 is larger than the reference voltage, the comparator 61 becomes high level, and when the output signal of the photodiode 43 is smaller than the reference voltage, the comparator 61 becomes low. Outputs a rectangular pulse that is level. 6 shows a signal waveform output from the comparator 61 when the zoom lens 22 moves from one end to the other end.

  The comparator 62 compares the output signal of the photodiode 53 with a reference voltage, and becomes a high level when the output signal of the photodiode 53 is larger than the reference voltage, and is low when the output signal of the photodiode 53 is smaller than the reference voltage. Outputs a rectangular pulse that is level. A lower part of FIG. 6 shows a signal waveform output from the comparator 62 when the zoom lens 22 moves from one end to the other end.

  The horizontal axis in FIG. 6 corresponds to the amount of movement from one end of the zoom lens 22. In FIG. 6, the movement amount when the zoom lens 22 is at the reference position is shown as zero.

  The counter 70 detects the rising and falling edges of the pulses output from the comparators 61 and 62, respectively, and counts the number of pulses. The counter 70 also compares the A phase signal and the B phase signal to determine the moving direction of the zoom lens 22. For example, when the zoom lens 22 is moving from one end to the other end, the B phase signal is at the low level at the pulse rising timing of the A phase signal shown in the middle of FIG. On the other hand, when the zoom lens 22 is moving from the other end to the one end, the B phase signal is at the high level at the pulse rising timing of the A phase signal shown in the middle of FIG. From this, the counter 70 can determine the moving direction of the zoom lens 22 by comparing the A phase signal and the B phase signal.

  When the output signal of the photodiode 43 reaches the peak value, the A / D converter 80 holds the peak value (the amplitude value of the output signal), converts the held amplitude value into a digital signal, and controls the lens. To the unit 20. When the zoom lens 22 moves from one end to the other end, the output value (peak value) at the apex of each peak portion of the upper waveform in FIG. 5 is sequentially held by the A / D converter 80, and the lens control unit 20 is output.

  When the output signal of the photodiode 53 reaches the peak value, the A / D converter 81 holds the peak value (amplitude value of the output signal) and converts the held amplitude value into a digital signal to control the lens. To the unit 20. When the zoom lens 22 moves from one end to the other end, the output value (peak value) at the apex of each peak portion of the lower waveform in FIG. 5 is sequentially held by the A / D converter 81, and the lens control unit 20 is output.

  The zoom position detection unit 25 and the lens control unit 20 configured as described above have the same configuration as that of a general incremental encoder except for the A / D converters 80 and 81.

  That is, the lens control unit 20 monitors the output signal of the comparator 60, and detects that the zoom lens 22 is at the reference position when the output signal becomes high level. Then, the lens control unit 20 resets the count value of the counter 70 at the time when the reference position is detected, and then sets the count value (the number of pulses of the A phase signal or the number of pulses of the B phase signal) output from the counter 70. Based on this, the position (relative position) of the zoom lens 22 with respect to the reference position is detected.

  However, the position of the zoom lens 22 relative to the reference position cannot be detected until the lens control unit 20 detects the reference position.

  Therefore, in the lens device 2, until the reference position is detected, the lens control unit 20 determines the peak value of the A phase signal and the peak value of the B phase signal output from the A / D converters 80 and 81. The absolute position of the zoom lens 22 is detected based on the calculation result using.

  FIG. 7 shows changes in the peak value of the A phase signal output from the A / D converter 80 shown in FIG. 3 and the peak value of the B phase signal output from the A / D converter 81 shown in FIG. FIG. 7 indicates the peak value (amplitude value) of the A phase signal waveform or the B phase signal waveform. The horizontal axis of FIG. 7 indicates the opening No of the slit portion arranged between the light emitting element and the light receiving element when the peak value of the A phase signal waveform or the B phase signal waveform is obtained. The opening No is a number indicating the number of the slits 42 and 52 from the left end. In FIG. 7, a staircase graph indicated by a solid line indicates a change in the peak value of the A phase signal, and a staircase graph indicated by a broken line indicates a change in the peak value of the B phase signal.

  FIG. 8 is a diagram illustrating a result of subtracting the peak value of the B-phase signal from the peak value of the A-phase signal at the same opening No. in FIG.

  The light emitting element and the light receiving element included in the sensor unit 40 and the light emitting element and the light receiving element included in the sensor unit 50 are the same in design. For this reason, the sensor unit 40 and the sensor unit 50 have substantially the same light emission amount fluctuation and light-sensitive element sensitivity fluctuation due to deterioration over time. Therefore, the result shown in FIG. 8 becomes a constant value even when the sensor unit 40 and the sensor unit 50 are deteriorated with age and the signals output from the photodiodes 43 and 53 have changed from the beginning of product shipment.

  In the lens device 2 of the present embodiment, at the time of manufacture and shipment, the zoom lens 22 is moved from the wide end to the tele end to acquire the data shown in FIG. 7, and the data shown in FIG. 8 is generated from the acquired data. Is stored in a ROM built in the lens control unit 20. Further, in this ROM, aperture No.-zoom position data in which each aperture No. in the data shown in FIG. 8 is associated with the position (absolute position) of the zoom lens 22 is stored.

  Each opening No. in the data shown in FIG. 8 is a common number for the two openings K constituting the pair. Therefore, the position of the zoom lens 22 corresponding to the aperture No in the aperture No.-zoom position data is the position of the zoom lens 22 corresponding to one of the two apertures K serving as the aperture No. Or the position of the zoom lens 22 corresponding to an intermediate position between the two openings K.

  When the power of the lens device 2 is turned on, the lens control unit 20 of the lens device 2 first moves the zoom lens 22 by a predetermined amount and acquires a peak value from the A / D converters 80 and 81.

  For example, a case where the relative position between the slit portion, the light emitting element, and the light receiving element is indicated by a broken line in FIG. In this case, for example, the lens control unit 20 moves the zoom lens 22 to the tele end side until the relative position between the slit portion, the light emitting element, and the light receiving element reaches the position indicated by the one-dot chain line in the drawing.

  In this moving process, the opening K of the opening No. 6 of the slit part 42 overlaps the light receiving element and the light emitting element of the sensor part 40. From the light receiving element of the sensor part 40, the sixth peak in the A phase signal waveform of FIG. The value of the vertex of is output. Further, when the zoom lens 22 is moved, the A / D converter 80 holds the value of the peak of the sixth peak in the A-phase signal waveform of FIG. 5 as a peak value (amplitude value). It is converted and transmitted to the lens control unit 20.

  When the zoom lens 22 further moves, the aperture K of the aperture No. 6 of the slit portion 52 overlaps with the light receiving element and the light emitting element of the sensor unit 50, and the six light receiving elements of the sensor unit 50 in the B phase signal waveform of FIG. The value of the apex of the peak of the eye is output. Further, when the zoom lens 22 is moved, the A / D converter 81 holds the value of the peak of the sixth peak in the B-phase signal waveform of FIG. 5 as a peak value (amplitude value). It is converted and transmitted to the lens control unit 20.

  The lens control unit 20 stops the movement of the zoom lens 22 when the peak value is received from each of the A / D converters 80 and 81. Then, the lens control unit 20 performs an operation of subtracting the peak value of the B phase signal waveform from the peak value of the received A phase signal waveform.

  Next, the lens control unit 20 compares the result of this calculation with the data shown in FIG. 8 stored in the built-in ROM, and determines an aperture number that matches the result of this calculation. Next, the lens control unit 20 compares the determined aperture No and aperture No-zoom position data, and detects the position of the zoom lens 22 corresponding to the aperture No as the absolute position of the zoom lens 22.

  The lens control unit 20 may move the zoom lens 22 to the wide end side after the power is turned on.

  Next, a case where the relative position between the slit portion, the light emitting element, and the light receiving element is indicated by a broken line in FIG. 10 when the lens apparatus 2 is turned on will be described as an example. In this case, the lens control unit 20 moves the zoom lens 22 to the tele end side until the relative position between the slit part, the light emitting element, and the light receiving element reaches the position indicated by the one-dot chain line in FIG. Let's move to. In this movement process, first, the lens control unit 20 receives an amplitude value corresponding to the opening K of the opening No 8 of the slit unit 52 from the A / D converter 81. Thereafter, the lens control unit 20 receives an amplitude value corresponding to the opening K of the opening No 9 of the slit part 42 from the A / D converter 80.

  Similarly to the example of FIG. 9, the lens control unit 20 {(the amplitude value first received from the A / D converter 80 after power-on) − (the amplitude first received from the A / D converter 81 after power-on) If the absolute position of the zoom lens 22 is detected based on the calculation result and ROM data, the difference between the amplitude values corresponding to the apertures K that do not form a pair is obtained. Therefore, the position of the zoom lens 22 is erroneously detected.

  Therefore, the lens control unit 20 moves the zoom lens 22 after turning on the power, and acquires information on the moving direction of the zoom lens 22 from the counter 70. The lens control unit 20 outputs an amplitude value from the A / D converter 80 and then outputs an amplitude value from the A / D converter 81 when the moving direction is from the wide end to the tele end. At this point, an operation for subtracting the amplitude value received from the A / D converter 81 at the time point from the amplitude value received from the A / D converter 80 immediately before is performed. Based on this calculation result and the ROM data The absolute position of the zoom lens 22 is detected.

  On the other hand, when the moving direction of the zoom lens 22 is from the tele end to the wide end, the lens control unit 20 outputs an amplitude value from the A / D converter 81 and then the amplitude from the A / D converter 80. When a value is output, an operation is performed to subtract the amplitude value received from the A / D converter 81 immediately before the time point from the amplitude value received from the A / D converter 80 at the time point. The absolute position of the zoom lens 22 is detected based on the ROM data.

  In this way, by selecting two amplitude values to be calculated according to the moving direction of the zoom lens 22, the absolute position of the zoom lens 22 can be determined regardless of the position of the zoom lens 22 immediately after the power is turned on. It can be detected with high accuracy.

  In the above description, the operation only after the power is turned on has been described. However, after the first absolute position is detected after the power is turned on, for example, the zoom lens 22 is moved by the user and the A / D converters 80 and 81 are moved. When the signal output from is updated, the absolute position is detected. When the lens control unit 20 receives a high level signal from the comparator 60 and detects the reference position of the zoom lens 22 while the zoom lens 22 is being moved by the user, the lens control unit 20 and the zoom position detection unit 25 are Then, the A / D converters 80 and 81 are stopped, and thereafter, they operate as a general incremental encoder.

  The zoom position detection unit 25 has been described so far, but the configuration of the focus position detection unit 24 and the aperture position detection unit 26 is the same as that of the zoom position detection unit 25. Even immediately after, it is possible to detect the focus position and the absolute position of the aperture.

  As described above, according to the lens device 2, even if the reference position of the zoom lens 22 is not detected, the absolute value of the zoom lens 22 can be calculated by the calculation using the output values of the A / D converters 80 and 81. The position can be detected. Further, since the absolute position of the zoom lens 22 is detected based on the difference between the two amplitude values output from each of the A / D converters 80 and 81, the absolute position of the zoom lens 22 can be detected even when the sensor units 40 and 50 have deteriorated over time. A decrease in detection accuracy can be prevented. Further, according to the lens device 2, the above-described effects can be obtained only by adding the A / D converters 80 and 81 to the configuration of the incremental encoder and further changing the program executed by the lens control unit 20. Manufacturing costs can be reduced.

  Below, the modification of this embodiment is demonstrated.

  Instead of the data shown in FIG. 8, the result obtained by subtracting the peak value of the A-phase signal from the peak value of the B-phase signal at each opening No. in FIG.

  Instead of the data shown in FIG. 8, the result of obtaining the ratio of the peak value of the A-phase signal to the peak value of the B-phase signal in each opening No. in FIG. 7 may be used. This ratio is a constant value even when the sensor unit 40 and the sensor unit 50 have deteriorated over time and the signals output from the photodiodes 43 and 53 have changed from the beginning of product shipment. For this reason, the lens control unit 20 acquires this ratio after turning on the power, and compares the acquired ratio with the data in the ROM, thereby accurately determining the absolute position of the movable optical element without being affected by aging deterioration. It becomes possible to detect well.

  The detection of the reference position is not limited to the combination of the sensor unit 30 and the comparator 60, and other well-known configurations may be employed.

  The data shown in FIG. 8 stores only data corresponding to a plurality of apertures No. (for example, aperture Nos. Of apertures at both ends) in the slit portion, and the lens control unit 20 uses the aperture No. as a variable from this data. A function to be generated may be generated, and an opening No corresponding to the difference or ratio may be obtained from the difference or ratio between the function and the amplitude value. Further, the function may be stored instead of the data shown in FIG.

  The sensor unit 40 is not limited to a configuration including a light emitting element, a slit part, and a light receiving element as long as the peak value of the output signal increases in accordance with the movement of the zoom lens 22 in one direction. Similarly, the sensor unit 50 is not limited to a configuration including a light emitting element, a slit part, and a light receiving element as long as the peak value of the output signal decreases in accordance with the movement of the zoom lens 22 in one direction. .

  For example, as shown in FIG. 11, the sensor unit 50 may be configured with a magnetic sensor 110 and a magnet scale 112, and the sensor unit 40 may be configured with a magnetic sensor 111 and a magnet scale 112. The magnetic sensors 110 and 111 and the magnet scales 112 and 113 are configured to relatively move in the left-right direction in FIG. 11 according to the movement of the movable optical element. The magnet scale 112 has a trapezoidal shape in which the width in the direction orthogonal to the relative movement direction decreases toward the relative movement direction. The magnet scale 113 has a shape in which the magnet scale 112 is reversed left and right in the relative movement direction, and further inverted vertically. In addition, the magnet scale 113 is arranged with an S pole and an N pole so that the phase is shifted with respect to the magnet scale 112.

  In the configuration of the sensor unit as shown in FIG. 11, the positions of the magnetic sensors 110 and 111 are shifted to the right as the zoom lens 22 moves. The magnet scale 112 that overlaps the magnetic sensor 110 is wide at the beginning of the movement of the zoom lens 22, and narrows as the zoom lens 22 moves. Therefore, the signal waveform output from the magnetic sensor 110 is the one shown in the lower part of FIG. On the other hand, the magnet scale 113 that overlaps the magnetic sensor 111 has a narrow width at the beginning of the movement of the zoom lens 22 and becomes wider as the zoom lens 22 moves. Therefore, the signal waveform output from the magnetic sensor 111 is the one shown in the upper part of FIG.

  In the above description, the interchangeable lens type imaging apparatus has been described, but the lens apparatus 2 may be an imaging apparatus fixed to the imaging apparatus body. Further, the present invention can be applied not only to a lens device for broadcasting but also to a compact digital camera with interchangeable lenses.

  As described above, the following items are disclosed in this specification.

  The disclosed lens device includes a movable optical element, a first sensor unit in which a peak value of an output signal increases in accordance with movement of the movable optical element in one direction, and the movable optical element in the one direction. A second sensor unit that reduces the peak value of the output signal in accordance with movement, a peak value of the output signal of the first sensor unit, and a peak value of the output signal of the second sensor unit. And an absolute position detector that detects the absolute position of the movable optical element based on the result.

  The disclosed lens apparatus includes a reference position detection unit that detects a reference position of the movable optical element, and the movable optical element by comparing the output signal of the first sensor unit and the output signal of the second sensor unit. A moving direction determining unit that determines a moving direction of the first optical sensor, and a count number of the output signal of the first sensor unit or a count number of the output signal of the second sensor unit. A relative position detector that detects a relative position, and until the reference position is detected by the reference position detector, the absolute position of the movable optical element is detected by the absolute position detector, and the reference position is After the detection, the detection of the absolute position is stopped, and the detection of the relative position by the relative position detection unit is started.

  In the disclosed lens apparatus, the absolute position detection unit is subject to the calculation according to the movement direction of the movable optical element determined by the movement direction determination unit until the reference position is detected. Two output signals are selected.

  In the disclosed lens apparatus, the calculation performed by the absolute position detection unit is a calculation for obtaining a difference between a peak value of the output signal of the first sensor unit and a peak value of the output signal of the second sensor unit, Or it includes what is the calculation which calculates | requires ratio of the peak value of the output signal of said 1st sensor part, and the peak value of the output signal of said 2nd sensor part.

  The disclosed lens device includes a storage unit that stores the calculation result in advance for each of a plurality of positions where the movable optical element moves, and the absolute position detection unit stores information stored in the storage unit. And the result of the calculation are used to detect the absolute position of the movable optical element.

  The disclosed imaging apparatus includes the lens apparatus and an imaging apparatus body that captures an optical image collected by the lens apparatus.

  The disclosed absolute position detection method of the movable optical element includes an output signal of a first sensor unit in which a peak value of an output signal increases in accordance with movement of the movable optical element in one direction, and the one of the movable optical elements. The absolute position of the movable optical element is detected based on the result of the calculation using the output signal of the second sensor unit in which the peak value of the output signal decreases with the movement in the direction.

2 Lens device 21 Focus lens 22 Zoom lens 23 Aperture device 20 Lens control unit 30, 40, 50 Sensor unit

Claims (7)

A movable optical element;
A first sensor unit in which a peak value of an output signal increases in accordance with movement of the movable optical element in one direction;
A second sensor unit in which a peak value of an output signal decreases in accordance with movement of the movable optical element in the one direction;
An absolute position detection unit that detects an absolute position of the movable optical element based on a calculation result using the peak value of the output signal of the first sensor unit and the peak value of the output signal of the second sensor unit. A lens device comprising: The lens device according to claim 1,
A reference position detector for detecting a reference position of the movable optical element;
A moving direction determination unit that determines the moving direction of the movable optical element by comparing the output signal of the first sensor unit and the output signal of the second sensor unit;
A relative position detection unit that detects a relative position of the movable optical element with respect to the reference position based on a count number of an output signal of the first sensor unit or a count number of an output signal of the second sensor unit. ,
Until the reference position is detected by the reference position detector, the absolute position of the movable optical element is detected by the absolute position detector, and after the reference position is detected, the detection of the absolute position is stopped. Then, the lens device that starts detection of the relative position by the relative position detection unit. The lens device according to claim 2,
The absolute position detection unit selects two output signals to be calculated according to the movement direction of the movable optical element determined by the movement direction determination unit until the reference position is detected. Lens device. The lens device according to any one of claims 1 to 3,
The calculation performed by the absolute position detection unit is a calculation for obtaining a difference between the peak value of the output signal of the first sensor unit and the peak value of the output signal of the second sensor unit, or the first sensor A lens device which is a calculation for obtaining a ratio between a peak value of the output signal of the unit and a peak value of the output signal of the second sensor unit. The lens device according to any one of claims 1 to 4,
A storage unit that stores the result of the calculation in advance for each of a plurality of positions to which the movable optical element moves;
The absolute position detection unit is a lens device that detects the absolute position of the movable optical element using information stored in the storage unit and a result of the calculation. The lens device according to any one of claims 1 to 5,
An imaging apparatus comprising: an imaging apparatus body that captures an optical image collected by the lens apparatus.   The output signal of the first sensor unit in which the peak value of the output signal increases according to the movement of the movable optical element in one direction, and the peak value of the output signal according to the movement of the movable optical element in the one direction. An absolute position detection method for a movable optical element, wherein the absolute position of the movable optical element is detected based on a calculation result using a decreasing output signal of the second sensor unit.

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