JP5094605B2 - Aperture position detector - Google Patents

Description

  The present invention relates to a diaphragm position detection device, and more particularly to a diaphragm position detection device that detects a set position of a diaphragm corresponding to a rotation angle of an iris ring that is rotatably provided on a lens barrel.

  In a photographic lens used for broadcasting or commercial television cameras, consumer video cameras, etc., the iris is adjusted by rotating an iris ring provided on the outer periphery of the lens barrel. It has been known. In this type of photographic lens, a motor and a potentiometer are connected to the iris ring so that the iris ring can be driven by the motor and the position (rotation angle) of the iris ring can be detected by the potentiometer. Things are known. In this way, when the motor and potentiometer are connected to the iris ring, it is possible not only to manually rotate the iris ring but also to perform servo control so that the iris is at the desired setting position (opening degree). It is.

  In many cases, the iris adjustment is automatically performed by the auto iris function. In this case, an iris command signal (iris command value) indicating an F value (aperture F value) indicating the set position of the iris is photographed from the camera body. This is given to a lens control unit (such as a drive unit installed in the lens barrel). The control unit of the photographic lens servo-controls the iris so that the F value indicated by the iris command value is obtained by driving the iris ring with a motor while detecting the rotation angle of the iris ring with a potentiometer.

  The iris ring is provided with an index for indicating the current aperture setting position. As this index, for example, “1.9”, “2.8”, “4”, “5.6”, “8”, “11”, “16”, “C” indicating F value (“C” is closed) Is printed on the outer periphery of the iris ring by printing, engraving, and the like, and an index line indicating the current F value is marked on the fixed portion of the lens barrel adjacent to the iris ring. On the contrary, in some cases, the index line is indicated by the iris ring, and the letter indicating the F value is indicated on the fixed portion of the lens barrel.

  When the iris is adjusted, the iris can be manually adjusted by manually operating the iris ring so as to obtain a desired F value while visually recognizing the index provided on the iris ring. Also, when adjusting the iris manually by manually operating the iris ring while grasping the brightness of the actually captured image, or when adjusting the aperture by servo control like the auto iris function above The current aperture setting position can be grasped from the F value indicated by the index provided on the iris ring.

  By the way, the rotation range (rotation angle range) of the iris ring includes a restriction end (open end and closed end) that mechanically restricts further rotation to an open side that opens the aperture and a close side that throttles the aperture. ) Is provided. At the time of factory shipment or the like, the output value (voltage value) of the potentiometer when the iris ring is set at the positions of the regulation ends on both sides is measured, and the value is stored in the control unit.

  Then, the relationship between the rotation angle of the iris ring and the output value of the potentiometer is assumed to be a linear ideal relationship, and based on the relationship and the output values of the potentiometers at the regulation ends on both sides stored in advance, An arbitrary rotation angle of the iris ring is associated with the output value of the potentiometer. Further, the rotation angle of the iris ring and the F value of the aperture are associated with each other in an ideal relationship determined by design conditions. Therefore, based on these relationships, the output value of the potentiometer and the F value of the aperture are associated with each other in a predetermined relationship. That is, the F value of the diaphragm that is electrically recognized from the output value of the potentiometer is determined at least in some relationship.

  Therefore, for example, when the aperture is servo controlled so that the F value is instructed by the iris command value from the camera body, the output value of the potentiometer is an output value corresponding to the F value instructed by the iris command value. The rotation angle of the iris ring is controlled so that the aperture F value that is electrically recognized by the output value of the potentiometer becomes the F value indicated by the iris command value. Yes.

In Patent Document 1, a setting position (rotation angle) of an operation ring rotatably provided on the lens barrel is detected, and the operation ring is mechanically positioned so as to be a position corresponding to the detected setting position. 2. Description of the Related Art There has been proposed an imaging apparatus that drives a lens that is not coupled to a motor with a motor so that the setting position of an operation ring can be detected with high resolution using a potentiometer and an encoder.
JP 2006-65238 A

  As described above, the rotation angle of the iris ring and the F value of the aperture are associated with each other in an ideal relationship determined by the design conditions, and the F value indicated by the index provided in the iris ring is also related to the rotation angle of the iris ring. Corresponding in the same relationship as the F value of the aperture. That is, when the iris ring is set to a desired rotation angle, the letter of the F value (for example, “1.9”, “2.8”, “4”) clearly indicated as an index so that the F value of the diaphragm at that time is indicated by the index. “,” “5.6”,...) Are marked at predetermined angular positions of the iris ring.

  However, the diaphragm adjustment mechanism as described above includes a variation in the linearity of the potentiometer (the relationship between the rotation angle of the detection shaft and the output value relative thereto), a mechanism that supports the iris ring in a rotatable manner, and an iris ring and a potentiometer. There is a manufacturing error such as a backlash of a mechanical coupling mechanism or the like, or an error in the printing position of an index. Therefore, the relationship between the rotation angle of the iris ring and the output value of the potentiometer, the relationship between the rotation angle of the iris ring and the F value of the iris, and the relationship between the rotation angle of the iris ring and the F value indicated by the index are the ideal values described above. Does not exactly match the relationship.

  Therefore, the F value of the diaphragm that is electrically recognized by the output value of the potentiometer does not exactly match the F value of the actual diaphragm and the F value indicated by the index due to the manufacturing error as described above. In the following description, the F value of the diaphragm that is electrically recognized by the output value of the potentiometer is simply referred to as the F value that is recognized by the output value of the potentiometer.

  Here, the error regarding the F value of the actual diaphragm has a relatively large allowable range, and even if the F value recognized by the output value of the potentiometer is handled as the F value of the actual diaphragm, the error does not cause a problem.

  On the other hand, an error related to the F value indicated by the index is problematic because the error is visible. For example, when the aperture is servo-controlled, the aperture is set at a position where the F value indicated by the iris command value matches the F value recognized by the output value of the potentiometer. At this time, the F value indicated by the index is different from the F value indicated by the iris command value (F value recognized by the output value of the potentiometer) due to the manufacturing error as described above. It becomes a state. In particular, if the F value indicated by the iris command value is the F value (“1.9”, “2.8”, “4”, “5.6”... Deviate from the state in which those F values are accurately shown (because the index line is not aligned with the center of the character with the F value), the misalignment is easily recognized, and the aperture control is not properly performed. There is a risk of user misunderstanding. Further, when the F value recognized by the output value of the potentiometer is displayed on the display means, the user can easily recognize that the displayed F value is different from the F value indicated by the index. ,There's a problem.

  The present invention has been made in view of such circumstances, and the F value indicated by the index provided on the iris ring is electrically recognized by the output value of the potentiometer regardless of the manufacturing error. It is an object of the present invention to provide a position detection device for a diaphragm that can be matched with the above.

  In order to achieve the above object, an iris position detecting device according to claim 1 is an iris ring that is rotatably provided on a lens barrel of a photographing lens, and is an iris for adjusting a set position of the iris. A diaphragm position detection apparatus, comprising: a ring; an index indicating an F value as a value indicating a current aperture setting position; and a potentiometer for detecting the aperture setting position. At the currently set rotation angle, the output value of the potentiometer is such that the F value indicated by the index matches the F value indicating the set position of the diaphragm that is electrically recognized by the output value of the potentiometer. And correcting the correction value obtained by the correction with the output value of the potentiometer.

  According to the present invention, by correcting the output value of the potentiometer, the F value indicated by the index can be matched with the F value electrically recognized by the output value of the potentiometer. When the F value indicated by the value is set, the F value indicated by the index can be matched with the F value indicated by the iris command value.

  According to a second aspect of the present invention, there is provided the iris position detecting device according to the first aspect, wherein the iris width of the F value specified by the index indicates the F value of one character width, When the rotation angle of the restriction ends on both sides of the iris ring is set, the output value of the potentiometer is set so that the F value indicated by the index and the F value recognized electrically are exactly the same. It is characterized by correction.

  According to the present invention, the F value indicated by the index and the F value electrically recognized by the output value of the potentiometer are accurately matched in the F value of one character width in which the deviation of the F value indicated by the index is conspicuous. Can do. For example, as in claim 3, the F value indicating F4 and F8 is the F value of one character width.

  According to the present invention, the F value indicated by the index provided on the iris ring can be made to coincide with the F value of the diaphragm that is electrically recognized by the output value of the potentiometer, regardless of the manufacturing error.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out a stop position detecting apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing the appearance of a lens barrel of a photographing lens to which the present invention is applied. The photographic lens in the figure is, for example, a camera body (not shown) of a broadcast or commercial television camera that is detachably mounted by a rear end mount, and is attached to the lens barrel 10 of the photographic lens. A focus ring 12, a zoom ring 14, and an iris ring 16 are rotatably provided.

  The focus ring 12 and the zoom ring 14 are connected to the focus lens and the zoom lens in the lens barrel. When these operation rings rotate, the focus lens and the zoom lens move in the optical axis direction in conjunction with the rotation. It is supposed to move. Therefore, by adjusting the setting positions of these operation rings, it is possible to perform focus adjustment (focus adjustment) and zoom adjustment (focal length adjustment) of the photographing lens.

  The iris ring 16 is connected to a diaphragm in the lens barrel. When the iris ring 16 rotates, the diaphragm in the lens barrel opens and closes in conjunction with this movement (the aperture of the diaphragm changes). Yes. Therefore, the aperture of the photographic lens can be adjusted by adjusting the setting position of the iris ring 16.

  The lens barrel 10 is equipped with a driving device 18 for driving all or a part of the focus ring 12, the zoom ring 14, and the iris ring 16 with a motor. In this embodiment, at least the iris is mounted. It is assumed that the ring 16 is driven by a motor.

  Hereinafter, only the configuration related to the iris ring 16 will be described. The iris ring 16 is provided with external teeth, and each of a motor 32 and a potentiometer 34 (see FIG. 3), which will be described later, disposed in the driving device 18. A gear attached to the shaft is engaged. Accordingly, by driving the motor 32, the iris ring 16 is rotated and the diaphragm is driven to open and close. Further, the current set position (rotation angle) of the iris ring 16 is detected based on the output value (voltage value) output from the potentiometer 34 (details will be described later).

  In the case of auto iris that automatically adjusts the iris, an iris command signal is given from the camera body to the driving device 18, and the F value indicating the set position (target position) of the iris is designated by the value (iris command value). It has become. The rotation angle of the iris ring 16 and the F value indicating the set position of the iris are associated with each other in an ideal relationship determined by design, and the output value of the potentiometer 34 is an output corresponding to the F value specified by the iris command value. The iris ring 16 is driven by the motor 32 so as to be a value (so that the F value of the diaphragm electrically recognized by the output value of the potentiometer 34 becomes the F value specified by the iris command value). As a result, the diaphragm is servo-controlled via the iris ring 16.

  The drive device 18 is not limited to an auto iris that automatically adjusts the aperture, but is provided with an F command iris command signal designated in accordance with a user's manual operation from the camera body, or an operating member for adjusting the aperture. The diaphragm servo control as described above is also performed when the diaphragm is adjusted so that the F value is arranged and the F value specified by the operation member is obtained. Further, as a manual iris that is not servo-controlled, it is possible to manually rotate the iris ring 16 by a hand holding the iris ring 16, but detailed description thereof is omitted.

  FIG. 2 is a development view of the iris ring 16 showing indexes provided on the iris ring 16. As shown in the figure, on the outer peripheral surface of the iris ring 16, characters indicating the F value when the diaphragm is stopped by one step from the open end (F1.9) (when the light quantity is reduced by 1/2), “1.9”, “2.8”, “4”, “5.6”, “8”, “11”, “16”, and “C” are printed, for example. “C” indicates a closed state when the aperture is completely closed.

  On the other hand, an index line 22 is marked on the fixed portion 20 of the lens barrel 10 adjacent to the iris ring 16. The F value at the position of the iris ring 16 indicated by the index line 22 is the F value indicated by the index, and is recognized by the user as the F value indicating the current set position of the aperture.

  FIG. 3 is a block diagram showing a circuit configuration for servo-controlling the aperture. In the figure, an iris block 30 includes a diaphragm and an iris ring 16 and shows a structural block having a mechanism for interlocking the rotation of the iris ring 16 and the opening / closing operation of the diaphragm. The iris block 30 is connected to the motor 32 and the potentiometer 34 for opening / closing the iris through the iris ring 16. Note that the present invention can be applied to the motor 32 and the potentiometer 34 as long as the motor 32 and the potentiometer 34 are connected directly or indirectly to the diaphragm, not via the iris ring 16.

  On the other hand, the circuit board disposed in the driving device 18 includes a CPU 40, an amplifier 42, an A / D converter 44, and an EEPROM 46. When the CPU 40 receives the iris command signal from the camera body during the servo control of the iris, the CPU 40 servo-controls the iris of the iris block 30 so that the F value indicated by the value of the iris command signal (iris command value) is obtained.

  Here, the output value of the potentiometer 34 and the F value indicating the aperture setting position (aperture F value) are associated with each other in a predetermined relationship.

  For example, the relationship between the iris ring 16, the rotation angle, and the output value of the potentiometer 34 is associated with a linear ideal relationship as shown in FIG. That is, the output values of the potentiometer 34 at the restriction ends on both sides when the iris ring 16 is set to the open end on the aperture opening side and the closed end on the aperture stop side are measured in advance at the time of factory shipment or the like. The output value at the open end is X0, and the output value at the close end is X3. Then, when the rotation angle of the iris ring 16 is changed between the open end and the closed end, the output value of the potentiometer 34 changes linearly in the range of values from X0 to X3, and thereby the iris ring The relationship between the 16 rotation angles and the output value of the potentiometer 34 is associated with a linear ideal relationship.

  On the other hand, the rotation angle of the iris ring 16 and the F value (diaphragm F value) indicating the set position of the iris are associated with each other in an ideal relationship determined by the design conditions, and are specified as an index as shown in FIG. The rotation angle of the iris ring 16 for setting each F value is determined by this relationship.

  Therefore, the output value of the potentiometer 34 and the F value of the diaphragm are associated with each other by these relations, and when the F value of the current diaphragm is detected from the output value of the potentiometer 34 or the diaphragm is set to a desired F value. The output value of the potentiometer 34 can be obtained.

  Therefore, when servo-controlling the diaphragm so that the iris command value becomes the F value as described above, the CPU 40 reads the output value (actually measured value) of the potentiometer 34 via the A / D converter 44. The current F value of the aperture can be recognized electrically. Then, by driving the motor 32 via the amplifier 42 and rotating the iris ring 16 so that the F value of the aperture matches the F value indicated by the iris command value, the iris command value is finally obtained. The aperture is set at a position where the F value indicated by. In the processing of the CPU 40, the aperture value is not controlled so that the F value of the aperture obtained from the output value of the potentiometer 34 matches the F value indicated by the iris command value. It is also possible to obtain the output value of the potentiometer 34 when the F value indicated by, and control the aperture so that the output value of the potentiometer 34 becomes that value, and there is no substantial difference in either case.

  By the way, as described in the section of “Problems to be Solved and Used by the Invention”, there is a manufacturing error in the above-described aperture adjustment mechanism, and the electrical error is generated by the output value of the potentiometer 34 due to the manufacturing error. In some cases, the F value of the aperture that is visually recognized does not exactly match the F value indicated by the index provided on the iris ring 16. Therefore, when the iris is set at a position where the iris command value indicates the F value as described above, the F value indicated by the iris command value (the F value of the iris electrically recognized by the output value of the potentiometer 34). And the F value indicated by the index may not match. For example, although the iris command value indicates F4 as the F value, a situation occurs in which the index does not accurately indicate F4 when the aperture is set according to this.

  In consideration of such circumstances, in the present embodiment, the output value (actually measured value) of the potentiometer 34 is corrected, and the corrected output value is simulated with the output value of the potentiometer 34, so that the output value of the potentiometer 34 is controlled. The F value of the aperture that is electrically recognized is matched with the F value indicated by the index. Hereinafter, correction of the output value of the potentiometer 34 will be described. In the following description, the F value of the diaphragm that is electrically recognized by the output value of the potentiometer 34 is simply referred to as the F value that is recognized by the output value of the potentiometer 34.

  As shown in FIG. 4, the output value of the potentiometer 34 when the iris ring 16 is set to the open end is X0, and the output value of the potentiometer 34 when the iris ring 16 is set to the close end is X3, and these values are measured in advance. Are stored in the EEPROM 46 of FIG.

  At this time, the rotation angle of the iris ring 16 and the output value of the potentiometer 34 connect the point P0 of the output value X0 at the open end and the point P3 of the output value X3 at the closed end as shown in FIG. Corresponding with the relationship of the straight line L0.

  Further, the rotation angle of the iris ring 16 and the F value of the diaphragm are associated with each other in an ideal relationship determined by the design conditions as described above. If the rotation angle of the iris ring 16 from the open end to the close end is 100%, for example, F4 is a rotation angle of 36% from the open end, and F8 is a rotation angle of 58% from the open end.

  Based on these relationships, as described above, the output value of the potentiometer 34 is also associated with the F value of the diaphragm, and the F value recognized by the output value of the potentiometer 34 is determined.

  On the other hand, assuming that the F value used for correction other than when the iris ring 16 is set to the open end and the closed end is F4 and F8, for example, F4 and F8 are used as the F values of the diaphragm based on the correspondence relationship of the straight line L0. The output value of the potentiometer 34 corresponding to is obtained, and the output values are set as X1 'and X2' as shown in FIG.

  Actually, the output value output from the potentiometer 34 when the iris ring 16 is set to the rotation angle where the index indicates each of F4 and F8 is measured, and the measured output values are X1, X2 as shown in FIG. And These output values X1 and X2 are actually measured in advance and stored in the EEPROM 46 of FIG.

  At this time, the actual relationship between the rotation angle of the iris ring 16 and the output value of the potentiometer 34 can be approximated by the relationship shown by the dotted line (broken line) L1 in FIG. That is, the point at which the output value of the potentiometer 34 becomes X1 at the rotation angle of the iris ring 16 when the index indicates F4, and the output value of the potentiometer 34 at the rotation angle of the iris ring 16 when the index indicates F8 is X2. P2 is a point P0 and a point P1, a point P1 and a point P2, and a point L2 and a point P3 are connected by a straight line. A relationship indicated by a dotted line L1 is a rotation angle of the iris ring 16 and a potentiometer 34. It is possible to approximate the actual relationship with the output value of.

  In such a situation, the output value of the potentiometer 34 is corrected by the potentiometer 34 in which the output values X1 and X2 of the potentiometer 34 when the index indicates F4 and F8 are associated with F4 and F8 as the F value of the diaphragm. The output value of the potentiometer 34 is corrected so that the output values X1 ′ and X2 ′ are obtained.

  Further, the output value of the potentiometer 34 other than when the index indicates F4 and F8 is also corrected so that the output value assumed by the dotted line L1 in FIG. 4 becomes a value on the straight line L0 indicating the ideal relationship.

Specifically, when the output value X of the potentiometer 34 is a value that satisfies the condition of X0 <X ≦ X1, the corrected output value (correction value) X ′ is expressed by the following equation (1):
X '= (X-X0). (X1'-X0) / (X1-X0) + X0 (1)
Is required.

  When the output value X of the potentiometer 34 satisfies a value satisfying X1 <X ≦ X2 and X2 <X ≦ X3, it can be obtained by the same calculation as the above equation (1), but is generalized as follows.

  When the iris ring 16 is set at the open end, when the index is set at the rotation angle indicating F4, when the index is set at the rotation angle indicating F8, when set at the closed end , Output values (actually measured values) output from the potentiometer 34 in order are array variables A [n] (n = 0, 1, A [0], A [1], A [2], A [3]). 2, 3).

  On the other hand, in the relationship between the output value of the potentiometer 34 associated with a predetermined relationship and the F value of the diaphragm, the F value of the diaphragm includes the open end, F4, F8, and the closed end of the potentiometer 34 associated with the closed end. The output value is represented in sequence by an array variable B [n] (n = 0, 1, 2, 3) B [0], B [1], B [2], B [3].

  At this time, under the above-described circumstances, the values A [0] = X0, A [1] = X1, A [2] = X2, A [3] = X3 are array variables A [n] (n = 0, 1 2 and 3), and B [0] = X0, B [1] = X1 ′, B [2] = X2 ′, and B [3] = X3 are array variables B [n] (n = 0, 1, 2, 3).

If the output value (actually measured value) of the potentiometer 34 thus obtained is X, when the output value X satisfies the condition of A [n−1] <X ≦ A [n], the correction value X ′ is The following formula (2),
X ′ = (X−A [n−1]) · (B [n] −B [n−1]) / (A [n] −A [n−1]) + B [n−1] (2 )
Is required.

  In this way, the output value X of the potentiometer 34 is corrected by the above equation (2), and the correction value X ′ is simulated with the output value X of the potentiometer 34, whereby the F value recognized by the output value of the potentiometer 34, The F value indicated by the index can be matched. Therefore, for example, when the iris is set at a position where the F value indicated by the iris command value is set, the F value indicated by the iris command value matches the F value indicated by the index.

  In the above description, the F values used for corrections other than the open end and the closed end have been described as F4 and F8. However, the F values ("1.9", "2.8", "4", "5.6", "8", "11", "16", "C"), a desired F value can be used as an F value used for correction. At this time, in the F value used for correction, the F value of the diaphragm associated with the output value of the potentiometer 34 can be accurately matched with the F value indicated by the index.

  However, F4 and F8 have a character width of one character such as “4” and “8”, and are narrower than other F values. For this reason, when the iris ring 16 is set at a rotation angle at which the diaphragm has these F values, the deviation is noticeable unless the index line indicates the center of these characters. Therefore, F4 and F8 are used for correction. Is desirable.

  For the F values used for correction, the array numbers n starting from 0 of the array variables A [n] and B [n] in descending order from the output value of the potentiometer 34 when the index indicates those F values. To be assigned. That is, as shown in FIG. 4, when the output value of the potentiometer 34 increases as the F value increases (shifts from the open side to the closed end), the array starts from 0 in ascending order of the F value. The number n is assigned.

  Then, the output value (actual value) of the potentiometer 34 when the index indicates the F value of the array number n is substituted into the array variable A [n], and is associated with the F value of the array number n as the aperture F value. The output value of the potentiometer 34 is substituted into the array obtaining variable B [n]. Thus, the correction value X ′ when the output value X of the potentiometer 34 satisfies the condition of A [n−1] <X ≦ A [n] can be obtained from the above equation (2).

It should be noted that the F value ("1.9", "2.8", "4", "5.6", "8", " 11 ”,“ 16 ”,“ C ”) are all assigned F numbers to be used for correction, array numbers n (0 to 7) are assigned, and actual values are assigned to array variables A [n]. (The embodiment shown below corresponds to this). In this case, as a condition for applying the above equation (2), the output value X of the potentiometer 34 satisfies the condition of A [n−1] <X ≦ A [n]. It is assumed that X satisfies the condition of A [m] <X ≦ A [n], and array variables m and n include A [m] <X ≦ A [ n] is satisfied, and the difference between m and n is minimized. Then, the equation in which the array variable (n−1) is replaced with m in the above equation (2) may be an equation for calculating the correction value X ′. That is,
X ′ = (X−A [m]) · (B [n] −B [m]) / (A [n] −A [m]) + B [n] (2) ′
And it is sufficient.

  FIG. 5 is a diagram showing a data configuration in the EEPROM 46 in which data for correcting the output value of the potentiometer 34 is stored as described above in the present embodiment. In the memory area of the EEPROM 46, when the index indicates each F value with respect to the F value (F1.9, F2.8, F4, F5.6, F8, F11, F16, C) specified as the index The memory area of the memory address (102 to 109) for storing the output value (actually measured value) of the potentiometer 34 is secured. Further, memory areas of memory addresses 101 and 110 for storing the output value (actually measured value) of the potentiometer 34 when the iris ring 16 is set to the open end and the closed end are secured.

  Then, each bit (0 to 7) of the memory area of the memory address 100 is sequentially associated with each F value (F1.9, F2.8, F4, F5.6, F8, F11, F16, C). And data (flag) indicating whether or not each F value is used for correction is recorded. The F value corresponding to the bit in which the value of 1 is recorded is used for correction, and the F value corresponding to the bit in which the value of 0 is recorded is not used for correction.

  The output value (actual value) of the potentiometer 34 when the iris ring 16 is set to the open end and the closed end is obtained by associating the rotation angle of the iris ring 16 with the output value of the potentiometer 34 as described above. This is data necessary for associating the output value and the aperture F value. Accordingly, actual values are recorded in the memory addresses 101 and 110 corresponding to these F values, and there is no flag such as each bit of the memory address 100 indicating whether or not to use for correction.

  Further, instead of the output value (actual value) of the potentiometer 34 when the iris ring 16 is set to the open end and the closed end, the iris ring 16 is set to a rotation angle at which the index indicates the F value (F1.9 and C) at both ends. The output value (actually measured value) of the potentiometer 34 at the time of setting is used, the rotation angle of the iris ring 16 and the output value of the potentiometer 34 are associated with each other, and the output value of the potentiometer 34 and the F value of the diaphragm are associated with each other. Good.

  The data stored in the EEPROM 46 is recorded in advance before operation (at the time of factory shipment or the like). During operation, the CPU 40 refers to these data and outputs the output value of the potentiometer 34 as described above. Make corrections. That is, referring to each bit of the memory address 100 of the EEPROM 46, the F number corresponding to the bit in which 1 is recorded is used as the F value used for correction, and the array number n starting from 0 is assigned to the F value as described above. . Here, it is assumed that 1 is recorded in all the bits of the memory address 100, and 0 to 7 in all F values of F1.9, F2.8, F4, F5.6, F8, F11, F16, and C. Are arranged in order.

  Then, among the bits of the memory address 100 of the EEPROM 46, the bit corresponding to the F value used for correction is referred to, and the actual measurement value for the F value corresponding to the bit in which 1 is recorded is stored in the memory addresses 102 to 109. Read from the memory area. Assuming that the array number of the F value from which the actual measurement value is read is n, the actual measurement value of the array number n is substituted into the array variable A [n].

  On the other hand, if the bit corresponding to the F value used for correction is 0 among the bits of the memory address 100 of the EEPROM 46, if the array number of the F value is n, the array variable A of the array number n No value is assigned to [n]. That is, the F value is not used for correction.

  Further, the CPU 40 reads the values of the memory addresses 102 and 109 of the EEPROM 46 as output values (actually measured values) of the potentiometer 34 when the iris ring 16 is set to the open end and the closed end, and the rotation angle of the iris ring 16 and the potentiometer. As shown in FIG. 4, the output value of 34 is associated with the ideal relationship of the straight line L0. Based on this relationship and the relationship between the rotation angle of the iris ring 16 determined by the design conditions and the F value of the iris, the potentiometer 34 The output value is associated with the aperture F value.

  Then, for each F value used for correction, the output value of the potentiometer 34 when the F value of the aperture is the F value of the array number n is obtained from the corresponding relationship and substituted into the array variable B [n].

  As described above, when the values are substituted into the array variables A [n] and B [n] for the F value used for correction based on the data stored in the EEPROM 46, the CPU 40 reads the output value of the potentiometer 34. In this case, the output value can be corrected by the above equation (2) ′.

  Next, the processing in the iris adjustment mode when creating data as shown in FIG. 5 in the EEPROM 46 will be described with reference to the flowcharts of FIGS.

  First, at the time of factory shipment or the like, an adjustment device such as a personal computer is connected to the drive device 18 shown in FIG. 1 to cause the CPU 40 of the drive device 18 to execute a desired process in response to a command from the adjustment device. The desired iris command signal (iris command value) is supplied to the CPU 40. However, it is also possible to eliminate the need to connect an adjustment device to the drive device 18 by causing the drive device 18 to internally execute processing as described below.

  Further, in the stage before executing the process of the iris adjustment mode, the output value (actual value) of the potentiometer 34 when the iris ring 16 is set to the open end and the potentiometer 34 when the iris ring 16 is set to the close end. Output values (actually measured values) are actually measured, and these actually measured values are recorded in the memory addresses 101 and 110 of the EEPROM 46 as shown in FIG. These measured values associate the relationship between the rotation angle of the iris ring 16 and the output value of the potentiometer 34 as shown by the straight line L0 in FIG. 4, and the output value of the potentiometer 34 and the F value of the aperture correspond to each other. Attached. As a result, the F value of the aperture is electrically recognized from the output value of the potentiometer 34.

  When the adjustment device starts processing in the iris adjustment mode, first, bits 2 and 4 of the address 100 of the EEPROM 46 are set to 1 (other bits are 0) in the CPU 40 (step S10). Then, an iris command value indicating F4 is given to the CPU 40 (step 12). At this time, the CPU 40 reads the output value of the potentiometer 34 in the same manner as when the iris command value is given from the camera body, and the F value of the aperture recognized by the output value is the F value indicated by the iris command value. Servo-control the iris so that it matches (F4).

  Then, the user determines whether the F value indicated by the index of the iris ring 16 matches F4 indicated by the iris command value (whether the index line 22 points to the center of the character “4”). And the determination result is input to the adjusting device using a predetermined input means. The adjustment device determines whether or not the F value indicated by the index matches F4 based on the user's input (step S14). If it is determined NO, the adjustment command value to be given to the CPU 40 is increased or decreased. A certain amount is shifted in the decreasing direction (step S16). In addition, you may make it perform according to a user's operation how much an iris command value is shifted. Then, the process returns to step S14, and it is determined again whether or not the F value indicated by the index matches F4. In this determination, the processes in steps S14 and S16 are repeatedly executed while NO is determined. To do.

  On the other hand, if YES is determined in step S14, the output value of the potentiometer 34 at that time is stored as an actual measurement value in the memory address 104 of the EEPROM 46 corresponding to F4 as shown in FIG. 5 (step S18).

  Subsequently, the adjustment device gives the CPU 40 an iris command value indicating F8 (step S20). At this time, the CPU 40 reads the output value of the potentiometer 34 while reading the output value of the potentiometer 34, similarly to the case where the iris command value is given from the camera body, and the F value indicated by the iris command value. The diaphragm is servo-controlled so that it matches the value (F8).

  Then, in the same manner as described above, the adjustment device determines whether or not the F value indicated by the index matches F8 based on the user's input (step S22). The given iris command value is shifted by a certain amount in the direction of increasing or decreasing (step S24). Then, the process returns to step S22, and it is determined again whether or not the F value indicated by the index matches F8. In this determination, while it is determined NO, the processes of step S22 and step S24 are repeatedly executed. To do.

  On the other hand, if YES is determined in step S24, the output value of the potentiometer 34 at that time is recorded as an actual measurement value in the memory address 106 of the EEPROM 46 corresponding to F8 as shown in FIG. 5 (step S26).

  When the above processing is completed, the iris inspection processing of FIG. 7 is then executed. Here, when the processing of the flowchart of FIG. 6 is completed, the output value X of the potentiometer 34 is corrected using F4 and F8 as F values used for correction, and the correction value X ′ is used as the output value X of the potentiometer 34. Simulated processing is possible. In the iris inspection process, the servo control of the diaphragm is performed using the correction value X ′ as the output value X of the potentiometer 34 as described above, and whether or not the correction is appropriate when F4 and F8 are used as the F value used for the correction. Inspect. Only when it is not appropriate, the F value used for correction is added or changed.

  First, the adjustment device sets the parameter n to 0 (step S30), and repeats the processing from step S32 onward until the parameter n is increased by 1 while increasing the parameter n by 1. First, in step S32, an iris command value F (n) for instructing the F value of the array element number n is given to the CPU 40 (step S32). At this time, the CPU 40 servo-controls the diaphragm so that the F value recognized by the output value of the potentiometer 34 matches the F value indicated by the iris command value. However, as described above, the output value of the potentiometer 34 is a correction value corrected by the actual measurement values of F4 and F8, and the F value recognized by this correction value is the F value of the aperture indicated by the iris command value. Servo-control the iris so that they match.

  Then, the adjustment device determines whether or not the F value indicated by the index matches the F value of the array element number n based on the user input (step S34). When it determines with YES, it is determined whether the parameter n is 7 or more (step S36). If NO is determined, 1 is added to the parameter n, and the process returns to step S32. If it is determined as YES in step S36, the iris inspection process is terminated.

  On the other hand, if it is determined NO in step S34, the adjustment device sets the bit n of the address 100 of the EEPROM 46 to 1 in the CPU 40 (step S40). Then, the iris command value given to the CPU 40 is shifted by a certain amount in the direction of increasing or decreasing (step S42). Subsequently, based on the user input, it is determined whether or not the F value indicated by the index matches the F value of the array element number n (step S44), and while it is determined NO in this determination, Steps S42 and S44 are repeated.

  If YES is determined in step S44, the output value (uncorrected output value) obtained from the potentiometer 34 at that time is used as the actual measurement value, and the memory address (101 to 101) of the EEPROM 46 corresponding to the F value of the array element number n. 108) (step S46). Then, the process returns to step S32.

FIG. 1 is a diagram showing the appearance of a lens barrel of a photographing lens to which the present invention is applied. FIG. 2 is a development view of the iris ring showing indexes provided for the iris ring. FIG. 3 is a block diagram showing a circuit configuration for servo-controlling the aperture. FIG. 4 is a diagram showing the relationship between the rotation angle of the iris ring, the output value of the potentiometer, and the F value. FIG. 5 is a diagram showing a data configuration in the EEPROM in which data for correcting the output value of the potentiometer 34 is stored. FIG. 6 is a flowchart showing a processing procedure in the iris adjustment mode. FIG. 7 is a flowchart showing a processing procedure in the iris test.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Lens barrel, 16 ... Iris ring, 18 ... Drive apparatus, 20 ... Fixed part, 22 ... Index line, 30 ... Iris block, 32 ... Motor, 34 ... Potentiometer, 40 ... CPU, 46 ... EEPROM

Claims (3)

An iris ring rotatably provided on the lens barrel of the photographing lens, and an iris ring for adjusting the aperture setting position, and an iris ring provided on the iris ring and indicating a current aperture setting position F In an aperture position detection device comprising an index indicating a value and a potentiometer that detects a set position of the aperture,
In the rotation angle at which the iris ring is currently set, the F value indicated by the index matches the F value indicating the set position of the diaphragm that is electrically recognized by the output value of the potentiometer. A diaphragm position detecting device, wherein an output value of a potentiometer is corrected, and a correction value obtained by the correction is simulated with an output value of the potentiometer.   In the case where the rotation width of the iris ring in which the character width of the F values specified by the index indicates the F value of one character width and the rotation angles of the restriction ends on both sides of the iris ring are set, 2. The aperture position detection device according to claim 1, wherein the output value of the potentiometer is corrected so that the F value indicated by and the electrically recognized F value exactly match each other.   3. The aperture position detection apparatus according to claim 2, wherein the F value of one character width is an F value indicating F4 and F8.

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