JP2004294823A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera capable of accurately controlling the aperture diameter of a diaphragm. <P>SOLUTION: A diaphragm member through which object light made incident passes and which has a plurality of diaphragm blades has detection apertures mutually superposed over the plurality of diaphragm blades when a specified aperture diameter midway between the minimum aperture diameter and the maximum aperture diameter of the aperture formed by the diaphragm member is formed by the diaphragm member at a position different from the aperture formed by the diaphragm member having the plurality of diaphragm blades. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention has a plurality of aperture blades stacked, and a built-in aperture member that changes the aperture diameter by the relative movement of the plurality of aperture blades, and an object incident through the aperture of the aperture member The present invention relates to a camera that takes a picture by capturing light.
[0002]
[Prior art]
In recent years, video cameras capable of taking still images have been rapidly spread.
[0003]
In such a video camera, the sharpness required for a still image is secured by increasing the number of pixels of the mounted CCD.
[0004]
By the way, some video cameras adopt a diaphragm equipped with a galvanometer, which is called a galvano type. This is because the video camera records sound together with the image, so it is necessary to reduce the driving sound of the diaphragm that changes following the luminance of the field, and the galvano-type diaphragm is highly quiet when driven. This is because it has features.
[0005]
FIG. 1 is a schematic view of a galvano-type diaphragm.
[0006]
FIG. 1 shows a diaphragm blade 103 composed of a first diaphragm blade 103a and a second diaphragm blade 103b, a diaphragm drive unit 100 composed of a rotating rotor 100a and a post 100b, and a galvanometer 106, which constitute this diaphragm. The galvanometer 106 also shows a state in which a hall element 107 described later is disposed. A diaphragm aperture 1030 is formed by relatively moving the first diaphragm blade 103a and the second diaphragm blade 103b.
[0007]
FIG. 2 is an internal configuration diagram of the galvanometer.
[0008]
In FIG. 2, the rotation shaft 106a which is a component of the galvanometer 106, the magnet 106b attached to the rotation shaft 106a, and the rotation amount of the rotation shaft 106a attached to the magnet 106b are controlled. The driving coil 106c and the braking coil 106d are shown.
[0009]
In the galvanometer 106, a line of magnetic force is generated by passing a current through the driving coil 106c, and this generated magnetic force is used as a driving force for rotating the magnet 106b. An electromotive force is generated in the braking coil 106d by changing the peripheral magnetic field of the braking coil 106d by the rotation of the magnet 106b, thereby controlling the current flowing in the driving coil 106c, and the rotation of the magnet 106b is performed at a predetermined angle. Set to The Hall element 107 detects the rotation angle information of the magnet 106b by detecting the strength and polarity of the magnetic field at the position where the Hall element is attached.
[0010]
For this galvano-type diaphragm, it is necessary that correspondence between the rotation angle information of the galvanometer detected by the position detection sensor such as the Hall element 107 and the aperture diameter of the diaphragm is taken with high accuracy. Proposals have been made for taking measures with high accuracy (see, for example, Patent Document 1).
[0011]
In the above proposal, when the intensity of the magnetic field changes due to the change in the ambient temperature, the correspondence between the rotation angle information of the galvanometer and the aperture diameter of the diaphragm is maintained when the magnetic force from the magnet becomes zero. This is achieved by arranging Hall elements so that the aperture diameter is the same.
[0012]
Also, the correspondence between the rotation angle information of the galvanometer and the aperture diameter of the diaphragm is maintained by the method described below.
[0013]
FIG. 3 is a view showing a part of the galvano-type diaphragm shown in FIG.
[0014]
As described above, the aperture driving unit 100 shown in FIG. 3 includes the rotating rotor 100a and the post 100b, and the rotating rotor 100a is attached to the rotating shaft 106a of the galvanometer 106.
[0015]
In FIG. 3, posts 100b provided at both ends of the rotating rotor 100a are loosely fitted into insertion holes 1031b provided at the end of the second diaphragm blade 103b, and the rotating rotor 100a rotates counterclockwise. It also shows how they are about to start.
[0016]
When the rotation shaft 106a of the galvanometer 106 is rotated by a predetermined angle, the rotation rotor 100a is also rotated. When the rotation rotor 100a is rotated, the post connected to the rotation rotor 100a. These two diaphragm blades move in opposite directions through 100b. The insertion hole 1031b provided at the end of each of the two diaphragm blades of the galvano-type diaphragm is a perforation hole that can ensure the freedom of operation of the post 100b in the insertion hole. Therefore, as described above, when the rotation rotor 100a starts to rotate counterclockwise, the post 100b is pressed against the inner surface 10311b of the insertion hole 1031b, and the inner surface 10312b of the insertion hole 1031b opposite to the inner surface 10311b. A gap 1032b is formed on the side.
[0017]
Such a gap causes backlash and is formed on the inner surface 10311b side of the insertion hole 1031b not only when the rotating rotor 100a starts to rotate counterclockwise, that is, when it starts to rotate clockwise.
[0018]
FIG. 4 is a diagram illustrating changes in the aperture opening when the rotation angle of the galvanometer is reciprocated within a predetermined range.
[0019]
FIG. 4 shows the change in F value of the aperture when the galvanometer rotation angle is rotated from α on the “open” side of the aperture to β on the “small aperture” side. After the rotation angle reaches β, the change in the F value of the aperture when the rotation angle is returned to α is shown in B (referred to as change B). Has been.
[0020]
As shown in FIG. 4, the change A and the change B have different F values corresponding to a predetermined rotation angle between the rotation angle α and the rotation angle β. This is because although the rotation angle information is the same for a camera that knows the current F value of the aperture based on the rotation angle information from the Hall element 107 that detects the rotation angle of the galvanometer. This is a problem because the actual aperture diameter may be different.
[0021]
Therefore, in a camera or the like that employs this galvano-type diaphragm, the direction of changing the aperture diameter when the diaphragm aperture diameter is stopped at the target diaphragm aperture diameter is made constant so that the F value is inaccurate due to this backlash. I compensate. In other words, when stopping the F value of the aperture opening at a predetermined F value, either “open” side to “small aperture” side or “small aperture” side to “open” side is selected. It is done. This will be described with reference to FIG. 3, for example, when the galvanometer is intermittently rotated counterclockwise in the state shown in FIG. 3 (this is a change from the “open” side to the “small aperture” side). In addition, since the post 100b always remains in contact with the inner surface 10311b of the insertion hole 1031b, the influence of backlash can be eliminated. However, when the galvanometer is rotated clockwise from the state in which the post 100b is in contact with the inner surface 10311b of the insertion hole 1031b shown in FIG. 3, the post 100b is opposite to the inner surface 10311b of the insertion hole 1031b. Although the rotating rotor rotates until it abuts against the inner surface 10312b, the aperture diameter (F value) of the diaphragm does not change. At this time, the rotation angle information detected by the Hall element 107 does not correspond to the aperture diameter (F value) of the diaphragm. Therefore, in order to accurately correspond the rotation angle information detected by the Hall element 107 and the aperture diameter (F value) of the aperture, as described above, the aperture aperture diameter (F value) is set to a predetermined aperture. The direction of stopping at the aperture (F value) must always be performed either from the “open” side to the “small aperture” side, or always from the “small aperture” side to the “open” side.
[0022]
[Patent Document 1]
JP-A-4-83113
[0023]
[Problems to be solved by the invention]
However, in order to make the rotation angle information detected by the Hall element coincide with the aperture diameter of the aperture, as described above, either from the “open” side or always from the “small aperture” side. There is a problem that it is troublesome that the aperture stop must be stopped at a predetermined F value while complying with it.
[0024]
Note that the above problem is not limited to a video camera equipped with a galvano-type diaphragm, but has a reason similar to that described above, for example, a digital still camera that employs a galvano-type diaphragm to require quietness of driving sound. The same problem occurs in a so-called silver salt camera that takes a picture on a roll film.
[0025]
In view of the above circumstances, an object of the present invention is to provide a camera capable of controlling the aperture diameter with high accuracy.
[0026]
[Means for Solving the Problems]
In order to achieve the above object, the camera of the present invention comprises:
A diaphragm member that has a plurality of overlapped diaphragm blades and changes the aperture diameter by relative movement of the plurality of diaphragm blades is incorporated, and the subject light incident through the aperture of the diaphragm member is captured. In cameras that shoot with
Each of the plurality of diaphragm blades constituting the diaphragm member is located in the middle between the minimum opening diameter and the maximum opening diameter at a position different from the opening of the diaphragm member due to relative movement of the plurality of diaphragm blades. When an opening having a predetermined opening diameter is formed, the detection apertures overlap each other over the plurality of diaphragm blades.
A diaphragm drive unit having a drive shaft and relatively moving the plurality of diaphragm blades via the drive shaft;
A drive shaft sensor for detecting the position or orientation of the drive shaft;
A light emitting and receiving sensor for detecting an overlap between the detection apertures;
Based on detection values of both the drive shaft sensor and the light projecting / receiving sensor, the diaphragm driving unit is configured to apply the plurality of diaphragm blades to the diaphragm while correcting backlash of the plurality of diaphragm blades. And a diaphragm control unit that is driven so that the opening diameter of the opening of the member becomes a desired opening diameter.
[0027]
In the camera according to the present invention, when the detection apertures of the plurality of diaphragm blades overlap each other, a diaphragm aperture having a predetermined aperture diameter is formed. Corresponds to the detection value from the drive shaft sensor when the detection value detected by the drive shaft sensor represents an aperture diameter different from the predetermined aperture diameter when the detection openings of the blades overlap each other. A correction is made to reflect the difference between the aperture diameter to be performed and the predetermined aperture diameter in the detected value, and an instruction to the aperture drive unit is made based on the corrected detected value. Thus, in the camera of the present invention, when the aperture diameter is set to a desired aperture diameter, the predetermined aperture diameter is set at least once before the aperture diameter of the aperture is changed to the same diameter as the desired aperture diameter. By passing through, the detected value from the drive shaft sensor can be ensured. In addition, by storing the correction amount corrected by passing through the predetermined opening diameter, when passing through the predetermined opening diameter and passing through the opening diameter by mistake when moving to the desired opening diameter. Even when the aperture diameter is returned to the desired value, the stored correction value is reflected in the detection value, so that the desired aperture diameter from the direction opposite to the first transition direction, which was impossible in the past, is obtained. Even if this is stopped, the change to the desired opening diameter can be performed accurately. Therefore, according to the camera of the present invention, the aperture diameter can be controlled with high accuracy.
[0028]
Here, the light projecting / receiving sensor may be a transmissive light projecting / receiving sensor.
[0029]
By doing in this way, it can complete by the simple process of providing the opening which mutually overlaps in all the several diaphragm blades.
[0030]
Alternatively, the light projecting / receiving sensor is a reflection type light projecting / receiving sensor, and one of the plurality of aperture blades disposed on the side farthest from the reflection type light projecting / receiving sensor is provided in the detection opening. Instead, it may have a mark that makes the reflectance of light from the reflection type light projecting / receiving sensor different.
[0031]
In this way, it is possible to cope with a case where the space on the front side or the other side of the plurality of diaphragm blades is not sufficient.
[0032]
The diaphragm drive unit may be a galvanometer, and the drive shaft sensor may be a Hall element.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 5 is an external perspective view of the first embodiment of the camera of the present invention.
[0034]
The digital camera 1 according to the present embodiment shown in FIG. 5 is a digital camera having a function of shooting a moving image in addition to a function of shooting a subject image formed on a CCD solid-state imaging device as a still image, A galvano aperture is used as the aperture.
[0035]
FIG. 5 shows a housing 2, a flash light emission window 12, a release button 13 composed of a two-stage switch, and a viewfinder objective window.
[0036]
FIG. 6 is an internal configuration diagram of the digital camera according to the present embodiment.
[0037]
FIG. 6 shows a lens 11 that collects subject light, an aperture blade 103, an image sensor (CCD) 102, an A / D converter 117, an output terminal 105, and a signal processing circuit 104. The subject light that has passed through is imaged and photoelectrically converted on the image sensor.
[0038]
The aperture blade 103 can be completely closed while adjusting the amount of subject light applied to the image sensor 102. The output terminal of the image sensor 102 is connected to the input terminal of the A / D converter 117, and the output signal from the image sensor 102 is analog / digital converted. The output terminal of the A / D converter 117 is connected to the input terminal of the signal processing circuit 104, and the digital output from the A / D converter 117 is input to the signal processing circuit 104 and becomes a video signal at the output terminal 105. Is output.
[0039]
6 also shows a microcomputer 109 (hereinafter abbreviated as a microcomputer) 109, a galvanometer 106, a Hall element 107, an electronic shutter control circuit 108, a synchronization signal generation circuit 116, a light projecting element 123, and a light receiving element 124. The signal processing circuit 104 is connected to a microcomputer 109 (hereinafter abbreviated as a microcomputer) through respective transmission lines for transmitting a memory control circuit control signal 118, signal amount information 114, and a moving image / still image switching signal 119. Has been.
[0040]
The galvanometer 106 is connected at its input end to the microcomputer 109, and controls the diaphragm blade 103 by the diaphragm control signal 111 from the microcomputer 109.
[0041]
The hall element 107 is connected to the microcomputer 109, detects rotation angle information of the galvanometer, and inputs it to the microcomputer 109 as an aperture position detection signal 112.
[0042]
The electronic shutter control circuit 108 has an input terminal connected to the microcomputer 109 and an output terminal connected to the image sensor 102. Based on the electronic shutter speed control signal 113 from the microcomputer 109, the electronic shutter control circuit 108 is photoelectrically converted into the image sensor 102. The charge accumulation period is controlled by sweeping out the charge generated in step (b) during a predetermined period.
[0043]
The synchronization signal generation circuit 116 is connected to the microcomputer 109 and the electronic shutter control circuit 108, and supplies a vertical synchronization signal 115 indicating the start of each field of one screen to both.
[0044]
A release button 110, a moving image / still image switching button 122, and a flash control circuit 120 are connected to the microcomputer 109, and the flash 121 is controlled by the flash control circuit 120.
[0045]
The light projecting element 123 emits a constant amount of light, and the light receiving element 124 receives light emitted from the light projecting element 123 and inputs an output signal corresponding to the amount of received light to the microcomputer 109.
[0046]
Here, details of the signal processing circuit 104 will be described.
FIG. 7 is a block diagram showing the configuration of the signal processing circuit shown in FIG.
[0047]
The signal processing circuit 104 shown in FIG. 7 includes a selector circuit 201 that switches between moving images and still images. The input terminal of the selector circuit 201 is connected to the output terminal of the A / D converter 117, and the A / D shown in FIG. A digital signal from the D converter 117 is input as the moving image signal 208. The output terminal is also connected to each input terminal of the first memory 204 and the second memory 205, and the moving image signal 208 is input to the first memory 204 and the second memory 205. The first memory 204 temporarily stores video signals from odd lines of the image sensor, and the second memory 205 temporarily stores video signals from even lines of the image sensor. The first memory 204 and the second memory 205 are connected to the memory control circuit 206 to which the memory control circuit control signal 118 from the microcomputer 109 shown in FIG. 5 is input, and are controlled by the memory control signal 210 from the memory control circuit 206. The
[0048]
Output terminals of the first memory 204 and the second memory 205 are connected to an adder 207, and these are added by the adder 207. The output terminal of the adder 207 is connected to the other input terminal of the selector 201, and the still image signal 209 resulting from the addition is input to the selector 201. A moving image / still image switching signal 119 is input to the selector 201, and the output terminal of the selector 201 is connected to the input terminal of the camera signal processing circuit 202. The other output end of the camera signal processing circuit 202 is connected to the input end of the signal amount information detection circuit 203, and the signal amount information 114 is output from the output end of the signal amount information detection circuit 203.
[0049]
The operation at the time of moving image shooting and still image shooting in the above configuration will be described in detail.
[0050]
The digital camera 1 reads out pixels of the line 2n-1 (n is a natural number) in the odd field, and reads out pixels of the line 2n (n is a natural number) in the even field, both during moving image shooting and still image shooting. .
[0051]
The microcomputer 109 shown in FIG. 6 switches the selector circuit 201 of the signal processing circuit 104 to the moving image signal 208 side by the moving image / still image switching signal 119, and the signal processing is performed by the camera signal processing circuit 202. Will output a video.
[0052]
In still image shooting, the odd line signal read out in the odd field is stored in the first memory 204 by the memory control circuit signal 210 from the memory control circuit 206, and the even line read out in the even field. Are stored in the second memory 205. The odd-numbered line and even-numbered line signals once stored are repeatedly read out from the first memory 204 and the second memory 205 at the frame period in the same combination as the reading of the image sensor 102 at the time of moving image shooting, and are added by the adder 207. Still image signal. The selector circuit 201 is switched to the still image signal side by the moving image / still image switching signal 119, and the signal processing is performed by the camera signal processing circuit 202, whereby a still image is output from the output terminal 105.
[0053]
FIG. 8 is an external view of a galvano-type aperture employed in the digital camera of this embodiment.
[0054]
FIG. 8 shows a first diaphragm blade 103a, a second diaphragm blade 103b, a galvanometer 106 including a rotating rotor portion 106e, a post portion 106f, and a main body portion 106g, a light projecting element 123, and a light receiving element 124. . In FIG. 8, the optical axis of the light projecting element 123 is indicated by a one-dot chain line L, and the light projecting element 123 and the light receiving element 124 are arranged so that the centers thereof are on the optical axis. .
[0055]
FIG. 8 shows a state in which the first open side slit 1031a and the first small stop side slit 1032a are provided from the upper left end of the first aperture blade 103a, and from the upper left end of the second aperture blade 103b. A state in which the second small aperture side slit 1032b and the second open side slit 1031b are provided is shown.
[0056]
The two slits provided in each diaphragm blade shown in FIG. 8 overlap on the optical axis (L) shown in FIG. 8 when the aperture diameters of the diaphragms become two predetermined aperture diameters.
[0057]
FIG. 9 is a view when the galvano-type diaphragm shown in FIG. 8 is viewed from above.
[0058]
9A and 9B, two slits provided on the second diaphragm blade 103b are shown on each upper side, and two slits provided on the first diaphragm blade 103a on each lower side. A slit is shown.
[0059]
The state of a total of four slits shown in FIG. 9A shows the same state as the state of these four slits shown in FIG. 8, and thus the first open-side slit 1031a and the first slit of the first diaphragm blade 103a are the same. When the second opening-side slit 1031b of the two diaphragm blades 103b is completely coincident with each other, the diaphragm aperture 1030 formed by the first diaphragm blade 103a and the second diaphragm blade 103b has an aperture value of 'F8'. Is set.
[0060]
FIG. 9B shows the state of the first diaphragm blade 103a and the second diaphragm blade 103b when the rotating rotor 106e shown in FIG. 8 is rotated counterclockwise from the state shown in FIG. 9A. Compared to the state shown in FIG. 9A, the first diaphragm blade 103a has moved to the left and the second diaphragm blade 103b has moved to the right. As a result, it is shown that the first small diaphragm side slit 1032a of the first diaphragm blade 103a and the second small diaphragm side slit 1032b of the second diaphragm blade 103b are completely coincident with each other. The aperture value of the aperture 1030 formed by the blade 103a and the second aperture blade 103b is set to 'F22'.
[0061]
FIG. 10 is a diagram showing a change in element output output from the light receiving element shown in FIG. 8 when the aperture opening changes between “open” and “small aperture”.
[0062]
FIG. 10 shows that the aperture value of the aperture opening reaches a peak at “F8” and “F22”.
[0063]
FIG. 11 is an internal block diagram of the digital camera of the present embodiment.
[0064]
In FIG. 11, the diaphragm blade 103, a galvanometer 106 that drives the diaphragm blade 103 in accordance with a control signal from the diaphragm control unit 300, which will be described later, and a signal that represents the amount of light that has passed through the slit as an output level as described above. 1 shows a light projecting / receiving sensor 300 that outputs the image, an imaging device 102 on which imaging light that has passed through the aperture blades is imaged, and an aperture control unit that transmits a control signal to the galvanometer.
[0065]
A shooting operation in the digital camera 1 of the present embodiment will be described. In the digital camera 1, moving image shooting or still image shooting is selected by operating the moving image / still image switching button 122 shown in FIG.
[0066]
First, a case where still image shooting is performed will be described. In still image shooting, the aperture opening diameter must be controlled with a higher degree of accuracy than in moving image shooting, and the object of the present invention is to change the aperture to the desired aperture opening diameter while controlling the aperture where backlash occurs. It is to achieve with high accuracy.
[0067]
First, the case where the aperture diameter of the aperture is changed to the aperture value 'F8' when the slits provided in each of the two aperture blades of the digital camera 1 completely match will be described. This is performed by starting a peak value detection routine and a backlash search routine.
[0068]
FIG. 12 is a flowchart of a peak value detection routine that is started when the aperture opening is changed to the predetermined aperture value 'F8' from the open side.
[0069]
In step S1, the aperture diameter is first changed from the current diameter to the open side. This is a case where the rotating rotor 106e is on the right side of the state shown in FIG. Note that the rotation angle information of the galvanometer 106 is always transmitted from the hall element 107 to the aperture control unit 300.
[0070]
In step S2, the aperture diameter starts to change toward the small aperture side, and then in step S3, the output value from the light projecting / receiving sensor 310 and the output from the Hall element when this output is obtained as the peak candidate output value. The moving angle information is recorded. In this mode, the output value obtained at a predetermined timing is compared with the peak candidate output value at each predetermined timing, and this peak value is detected until an output value exceeding the peak candidate output value is detected. The candidate output value continues to be held, and the aperture value continues to change toward the small aperture (step S4). When the aperture value approaches “F8”, the signal output from the light projecting / receiving sensor 310 starts to increase.
[0071]
If the output value obtained at a predetermined timing exceeds the peak candidate output value in step S5, the process proceeds to step S6, and as described above, the current value is stored as the peak candidate output value together with the rotation angle information. . When this peak candidate output value is updated (step S6), a return to the open side is performed once in step S7. After that, if the output value obtained at a predetermined timing does not exceed the peak candidate output value updated this time, the change to the small aperture side is started again, and if it exceeds, the peak candidate output value is updated, and the output to the open side Is reversed.
[0072]
Thereafter, when it is found from the rotation angle information from the Hall element 107 that the aperture diameter has changed to the small aperture side exceeding the predetermined aperture value 'F8', this peak value detection routine is exited, and the backlash search routine is executed. to go into.
[0073]
FIG. 13 is a flowchart of the backlash search routine.
[0074]
In step S11, the aperture value is calculated from the rotation angle information recorded together with the peak candidate output value obtained in the peak value detection routine.
[0075]
In step S12, it is determined whether or not the calculated aperture value is the same as the predetermined aperture value 'F8'. If it is determined that the aperture value is not the same, it is recorded together with the peak candidate output value in step S13. The difference between the rotation angle information and the rotation angle information when the aperture diameter of the digital camera 1 is recognized as the aperture value “F8” is recorded as backlash information. In step S14, the peak aperture output value obtained by the peak value detection routine in which the output value obtained by the light projecting / receiving sensor 310 is set to the aperture diameter that has been changed to the small aperture side exceeding the predetermined aperture value 'F8'. Change to the open side until Thereby, the aperture diameter can be accurately set to a predetermined aperture value 'F8'. In step S14, the aperture value 'F8' is changed based on the peak candidate output value obtained in the peak value detection routine. However, the rotation angle information recorded together with the peak candidate output value by the determination in step S12. In this digital camera 1, since the deviation when the aperture angle is different from the rotation angle information when the aperture value is recognized as the aperture value 'F8' is a backlash, a predetermined aperture After passing the value “F8” once to the small aperture side, the backlash can be canceled by setting the aperture diameter to the aperture value “F8” while returning to the open side based on the rotation angle information from the Hall element 107. Therefore, it may return to 'F8' from the small stop side based on the rotation angle information from the Hall element.
[0076]
On the other hand, in step S12, the rotation angle information recorded together with the peak candidate output value is the same as the rotation angle information when the digital camera 1 recognizes that the aperture diameter is the aperture value “F8”. In step S15, the output value obtained by the light projecting / receiving sensor 310 is the peak value detection routine for the aperture diameter that currently exceeds the predetermined aperture value 'F8' and changes to the small aperture side. Until the peak candidate output value obtained in step 1 is reached. Thereby, the aperture diameter can be accurately set to a predetermined aperture value 'F8'. Thereafter, in step S16, the rotation angle information recorded together with the peak candidate output value and the Hall element at the time when the output value obtained by the light emitting / receiving sensor 310 becomes the peak candidate output value obtained by the peak value detection routine. The difference from the rotation angle information from is recorded as backlash information.
[0077]
As described above, the aperture diameter can be accurately changed to the predetermined aperture value 'F8' from the open side, and backlash information is also acquired at the same time.
[0078]
Next, a case where the aperture value changes from the open side to a predetermined aperture value “F22” will be described.
[0079]
This is performed by activating a peak value detection routine and a backlash search routine for changing from the open side to the second predetermined aperture value.
[0080]
FIG. 14 is a flowchart of a peak value detection routine that is started when the aperture value changes to “F22”, which is the second predetermined aperture value from the open side.
[0081]
The difference between the routine shown in FIG. 14 and the routine shown in FIG. 12 is that when an output value exceeding the currently recorded peak candidate output value is detected in step S25, the peak candidate output value in FIG. 14 has been returned to the open side after being updated, but in FIG. 14, the process proceeds to step S27 without returning, except that the movement to the small aperture side is continued. Since it is the same as the description, it is omitted.
[0082]
Thereafter, this routine is exited at a predetermined timing, the backlash search routine shown in FIG. 13 is started, and the aperture diameter is accurately changed to the predetermined aperture value 'F22'.
[0083]
In FIG. 14, the peak value detection routine started when the aperture value changes to “F22”, which is the second predetermined aperture value from the open side, has been described. However, the digital camera 1 uses this routine. Instead, the peak value detection routine shown in FIG. 12 may be started after the aperture value after passing “F8” is changed based on the rotation angle information from the Hall element 107.
[0084]
In the above description, the case where the predetermined aperture value 'F8' or 'F22' is approached from the open side has been described. However, even if this is the approach from the small aperture side, the changing direction is shown in FIGS. Since the direction is the same as that described in FIG. 14 and there is no essential change, the illustration and description of the flowchart are omitted. Accordingly, the direction in FIG. 13 is also reversed.
[0085]
Further, the case where the aperture value is changed to an aperture value 'F12' between predetermined aperture values 'F8' and 'F22', and to 'F5.6' and 'F32' outside these ranges will be described. .
[0086]
FIG. 15 is a flowchart of a routine started when the aperture opening is changed to an aperture value other than a predetermined aperture value.
[0087]
In the digital camera 1, at least once, after passing through one of the aperture value 'F8' and the aperture value 'F22' which is a predetermined aperture value, the target aperture value is changed. For the convenience of explanation, the flowchart shown in FIG. 5 describes a case where the target aperture value changes after passing through the nearest predetermined aperture value.
[0088]
In step S31, if the target aperture value is 'F12', either 'F8' or 'F22' is selected as the predetermined aperture value, and if the target aperture value is 'F5.6'. 'F8' is selected as the predetermined aperture value. If the target aperture value is “F32”, “F22” is selected as the predetermined aperture value.
[0089]
In step S32, the peak value detection routine and the backlash search routine shown in FIGS. 12 and 13 are started, and the change to the nearest predetermined aperture value and the backlash information are grasped.
[0090]
In step S33, whether the nearest predetermined aperture value matches the aperture value represented by the rotation angle information detected from the Hall element when the aperture opening diameter is changed to the nearest predetermined aperture value. If it is determined whether or not the two do not coincide with each other, the process proceeds to step S34, and based on the rotation angle information from the Hall element, the target aperture value is changed, and then this routine is terminated. . If it is determined in step S33 that they match, it is determined in step S35 whether or not the subsequent approach to the target aperture value is from the “open” side to the “small aperture” side. If it is determined that it is determined to be from the “open” side to the “small aperture” side, the process proceeds to step S36 and corresponds to the amount of backlash already recorded with respect to the aperture value represented by the rotation angle information from the Hall element. The aperture value to be subtracted is subtracted. In step S34, the target aperture value is changed based on the subtraction result, and then this routine is terminated. If it is determined in step S35 that the direction is not from the “open” side to the “small aperture” side, in step S37, the aperture value indicated by the rotation angle information from the Hall element 107 has already been recorded. After adding the aperture value corresponding to the backlash that is present and making a change to the target aperture value based on the addition result in step S34, this routine is terminated. As described above, in this digital camera 1, the backlash information can be grasped by passing through the nearest predetermined aperture value at least once, and thereby the deviation due to backlash can be corrected. The aperture diameter can be changed to the target aperture value with high accuracy without restricting the direction of the approach when changing to the aperture value.
[0091]
In the digital camera 1, the moving aperture is also changed to the target aperture size with high accuracy by the method described above for moving image shooting. In moving image shooting, since the aperture aperture diameter is not so accurate, the aperture aperture diameter may be controlled based on the rotation angle information from the Hall element.
[0092]
Next, a second embodiment of the camera of the present invention will be described.
[0093]
FIG. 16 is an external perspective view of a galvano-type aperture employed in the digital camera of the present embodiment.
[0094]
In FIG. 16, the light receiving element 124 is disposed beside the light projecting element 123 as compared with the galvano type diaphragm (see FIG. 8) employed in the digital camera 1, and the second diaphragm blade 303b includes a digital There is no slit as provided in the second diaphragm blade 103b of the camera 1, but instead of the portion of the second diaphragm blade other than the portion corresponding to the slit of the second diaphragm blade of the digital camera 1. A state is shown in which portions 3031b and 3032b to which a paint having a light reflectance different from the light reflectance is applied are provided.
[0095]
Finally, a third embodiment of the camera of the present invention will be described.
[0096]
FIG. 17 is an external perspective view of a galvano-type diaphragm employed in the digital camera of the present embodiment.
[0097]
FIG. 17 shows a state in which the photo interrupter 125 employed as the light projecting / receiving sensor of the present invention is disposed so as to sandwich the first diaphragm blade 103a and the second diaphragm blade 103b. The signal from the photo interrupter 125 becomes a rectangular wave different from the output change shown in FIG. In this case, the slit position is set so that an aperture value in the middle of the aperture value range outputting the peak value becomes a predetermined aperture value. Others are the same as those of the digital camera 1 and will not be described.
[0098]
In the first to third embodiments described above, the galvano-type diaphragm is used as the diaphragm and the hall element is used as the drive shaft sensor as an example. However, the present invention is not limited to this as long as the diaphragm generates backlash. In addition, as long as such an aperture is adopted, the present invention is not limited to the digital camera described in the embodiment, and may be a so-called silver salt camera that performs shooting on a roll-shaped film.
[0099]
【The invention's effect】
As described above, according to the camera of the present invention, the aperture diameter can be controlled with high accuracy.
[Brief description of the drawings]
FIG. 1 is a schematic view of a galvano-type diaphragm.
FIG. 2 is an internal configuration diagram of a galvanometer.
FIG. 3 is a view showing a part of the galvano-type diaphragm shown in FIG. 1;
FIG. 4 is a diagram showing a change in aperture opening when a rotation angle of a galvanometer is reciprocated within a predetermined range.
FIG. 5 is an external perspective view of the first embodiment of the camera of the present invention.
FIG. 6 is an internal configuration diagram of a digital camera according to the present embodiment.
7 is a block diagram of the configuration of the signal processing circuit shown in FIG. 6;
FIG. 8 is an external view of a galvano-type aperture employed in the digital camera 1 of the present embodiment.
9 is a view of the galvano-type diaphragm shown in FIG. 8 as viewed from above.
10 is a diagram showing a change in element output output from the light receiving element shown in FIG. 8 when the aperture opening changes between “open” and “small aperture”. FIG.
FIG. 11 is an internal block diagram of the digital camera of the present embodiment.
FIG. 12 is a flowchart of a peak value detection routine that is started when the aperture opening is changed to a predetermined aperture value 'F8' from the open side.
FIG. 13 is a flowchart of a backlash search routine.
FIG. 14 is a flowchart of a peak value detection routine that is started when the aperture value changes to “F22”, which is the second predetermined aperture value from the open side.
FIG. 15 is a flowchart of a routine that is started when the aperture opening is changed to an aperture value other than a predetermined aperture value.
FIG. 16 is an external perspective view of a galvano-type aperture employed in the digital camera of the present embodiment.
FIG. 17 is an external perspective view of a galvano-type aperture employing a photo interrupter as a light projecting / receiving sensor of the present invention.
[Explanation of symbols]
1 Digital camera
2 Case
11 Lens
12 Flash window
13 Release button
102 Image sensor
103 aperture
103a First aperture blade
1031a, 3031a First open side slit
1032a, 3032a First small aperture side slit
103b Second aperture blade
1031b, 3031b Second open side slit
1032b, 3032b Second small aperture side slit
103c Aperture aperture
104 Signal processing circuit
105 Output terminal
106 Galvanometer
106a Rotating shaft
106b magnet
106c Driving coil
106d Braking coil
106e Rotating rotor
106f post
106g body
107 Hall element circuit
108 Electronic shutter control circuit
109 Microcomputer
110 Release button
111 Aperture control signal
112 Aperture position detection signal
113 Electronic shutter speed control signal
114 Signal information
115 Vertical synchronization signal
116 Synchronous signal generation circuit
117 A / D converter
118 Memory control circuit control signal
119 Video / still image switching signal
120 Flash control circuit
121 Flash device
122 Shooting switch button
123 Light Emitting Element
124 light receiving element
125 photo interrupter
201 selector circuit
202 Camera signal processing circuit
203 Signal amount information detection circuit
204 First memory
205 Second memory
206 Memory control circuit
207 Adder
208 Video signal
209 Still image signal
210 Memory control signal
300 Aperture control unit
310 Emitter / Receiver Sensor

Claims (5)

A diaphragm member that has a plurality of overlapped diaphragm blades and changes the aperture diameter by the relative movement of the plurality of diaphragm blades is incorporated, and captures subject light that has entered through the aperture of the diaphragm member. In cameras that shoot with
Each of the plurality of diaphragm blades constituting the diaphragm member is located between the minimum opening diameter and the maximum opening diameter at a position different from the opening of the diaphragm member due to relative movement of the plurality of diaphragm blades. When an opening having a predetermined opening diameter is formed, the detection apertures overlap each other over the plurality of diaphragm blades.
A diaphragm drive unit having a drive shaft and relatively moving the plurality of diaphragm blades via the drive shaft;
A drive shaft sensor for detecting the position or orientation of the drive shaft;
A light emitting and receiving sensor for detecting the overlap between the detection apertures;
Based on detection values of both the drive shaft sensor and the light projecting / receiving sensor, the diaphragm driving unit is configured to apply the plurality of diaphragm blades to the diaphragm while correcting backlash of the plurality of diaphragm blades. A camera comprising: a diaphragm control unit that drives a member so that an opening diameter of a member has a desired opening diameter. 2. The camera according to claim 1, wherein the light projecting / receiving sensor is a transmissive light projecting / receiving sensor. The light projecting / receiving sensor is a reflection type light projecting / receiving sensor, and one diaphragm member disposed on the side farthest from the reflection type light projecting / receiving sensor among the plurality of diaphragm blades is replaced with the detection opening. 2. The camera according to claim 1, further comprising a mark for changing a reflectance of light from the reflection type light projecting / receiving sensor. The camera according to claim 1, wherein the aperture driving unit is a galvanometer. The camera according to claim 1, wherein the drive shaft sensor is a Hall element.

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