JP3931264B2 - camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a camera, and more particularly to a camera in which a zoom position is accurately detected by reversely controlling a zoom position of a zoom lens.
[0002]
[Prior art]
An autofocus device that measures the shooting distance using the triangulation method and moves the focus lens to the in-focus position based on the distance measurement value, and a zoom that moves the zoom lens to the specified zoom position by operating the zoom switch In a camera including a lens device, it is necessary to detect an accurate zoom position of the zoom lens in order to accurately control the focus lens to a position where the focus lens is in focus.
[0003]
When the zoom switch is turned off while the zoom motor is rotating, the camera disclosed in Japanese Patent Application Laid-Open No. 62-265632 immediately stops when the zoom motor is in the TELE direction (forward rotation), and when the zoom motor is in the WIDE direction (reverse rotation). Is rotated forward for a certain short time to reverse the zoom lens by a predetermined amount in the TELE direction. That is, the camera detects the exact zoom position of the zoom lens by always stopping the zoom lens when moving in the TELE direction.
[0004]
[Problems to be solved by the invention]
However, the camera disclosed in Japanese Patent Application Laid-Open No. Sho 62-265632 is wasteful in driving energy because the reversing control is performed every time when the photographer determines the focal length even when the position of the zoom lens is changed in small increments. There is a drawback of doing.
Further, the camera has a drawback that even if the photographer tries to change the zoom position only a little, the reversing control is performed every time the zoom switch is turned off, and the camera returns to the original position, so that it is difficult to use.
[0005]
The present invention has been made in view of such circumstances, and an object thereof is to provide a camera capable of saving drive energy.
[0006]
[Means for Solving the Problems]
  To achieve the above object, the present invention provides a zoom lens, a zoom switch that indicates a zoom position of the zoom lens, a zoom lens driving mechanism that moves the zoom lens by operating the zoom switch, a full-press and a half-press. A release switch that can be pressed and when the zoom lens moves and stops in one of the tele-direction and wide-direction movement directions of the zoom lens, and the release switch is pressed halfway, or the release switch A control unit that reversely controls the zoom lens driving mechanism so as to stop after the zoom lens moves by a predetermined amount in the other direction before the switch is pressed halfway and fully pressed.The reversing control by the control unit is performed based on the amount of rotation of the zoom motor in a range in which the zoom lens stopped during movement in one direction moves in the other direction and the zoom position does not change. .
[0007]
According to the present invention, when the zoom switch is operated, the zoom lens moves and stops in a predetermined direction out of the moving directions of the tele direction and the wide direction, and when the release switch is pressed halfway or halfway Before being pushed and fully depressed, the zoom lens moves backward by a predetermined amount in the other direction and stops. As described above, the present invention performs the reverse control of the zoom lens when the release switch is half-pressed, that is, when actually shooting, so that it is compared with the conventional device that performs the reverse control every time the zoom lens moves. Thus, driving energy can be saved.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a front view of a camera 100 showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a zoom lens incorporated in the camera 100.
In FIG. 2, the zoom lens includes three groups of a first group lens (variable magnification lens) 10, a second group lens (correction system lens) 20, and a third group lens (focus lens) 30. . The variable magnification lens 10, the correction system lens 20, and the focus lens 30 are fixed to the first group lens frame 12, the second group lens frame 22, and the third group lens frame 32, respectively.
[0009]
The first group lens frame 12 is disposed in the cam inner cylinder 14 so as to be freely advanced and retracted. That is, the cam inner cylinder 14 is formed with three linear grooves 14A. The cam inner cylinder 14 is inserted into the cam cylinder 16 and then fixed to the main plate 70. On the other hand, three guide pins 12 A are implanted in the first lens group frame 12, and these three guide pins 12 A are provided in the three linear grooves 14 A of the cam inner cylinder 14 and the three in the cam cylinder 16. Inserted into the cam groove 16A. As a result, the first lens group frame 12 (variable magnification lens 10) is guided in the optical axis L direction by the linear groove 14A of the cam inner cylinder 14 so as to be able to advance and retract in the optical axis L direction. Moving.
[0010]
The second group lens frame 22 and the third group lens frame 32 are respectively disposed in the guide bar support cylinder 24 so as to freely advance and retract. That is, the guide bar support cylinder 24 supports one end side of each of the three guide bars 26, 27, and 28, is fixed to the base plate 70, and is provided with the three guide bars 26, 27 between the base plate 70. , 28 are fixed. The second group lens frame 22 is guided by the guide bars 26 and 27 so as to freely advance and retract in the optical axis L direction, and the third group lens frame 32 is guided by the guide bars 27 and 28 so as to freely advance and retract in the optical axis L direction. .
[0011]
A guide pin 22A is implanted in the second group lens frame 22, and the guide pin 22A is formed in a cam groove (not shown) formed in the cam cylinder 16 through a long hole 24A of the guide bar support cylinder 24. ) Is engaged. Accordingly, the second group lens frame 22 (correction system lens 20) moves in the direction of the optical axis L by the rotation of the cam cylinder 16.
On the other hand, one end of the third group lens frame 32 is screwed into the lead screw 52 of the focus lens driving unit 50 through the long hole 24B of the guide bar support cylinder 24. The focus lens driving unit 50 includes a support frame 51 fixed to the base plate 70, a focus motor 52 including a step motor disposed on the support frame 51, the lead screw 53 rotated by the focus motor 52, The photointerrupter (not shown) is arranged on the support frame 51 and detects the reference position of the third group lens frame 32 (focus lens 30).
[0012]
The third lens frame 32 (focus lens 30) can be moved in the optical axis L direction by driving the focus motor 54 of the focus lens drive unit 50 and rotating the lead screw 52. The position of the focus lens 30 can be detected by the number of drive pulses applied to the focus motor 30 from the time when the reference position of the focus lens 30 is detected by a photo interrupter (not shown).
[0013]
An iris unit 40 is mounted on the second group lens frame 22. The iris unit 40 includes a diaphragm plate 42 in which a plurality of diaphragm holes are formed, and an iris motor 44 that rotates the diaphragm plate 42. By controlling the rotational position of the diaphragm plate 42, a desired value can be obtained. The aperture hole is positioned on the optical axis L, or the light shielding portion where no aperture hole is formed is positioned on the optical axis L.
[0014]
A cam cylinder driving unit 60 that rotates the cam cylinder 16 is fixed to the main plate 70. The cam cylinder drive unit 60 includes a zoom motor 61, a motor rotation detection unit including a rotating plate 62 having a plurality of light shielding blades and a photo interrupter 63 for detecting each light shielding blade, and a rotational driving force of the zoom motor 61 as a cam cylinder. The gear train 64 is transmitted to 16 ring gears 17.
[0015]
When the zoom motor 61 of the cam barrel drive unit 60 is rotated, the rotational driving force is transmitted to the ring gear 17 of the cam barrel 16 via the gear train 64. As a result, the cam cylinder 16 rotates along the outer periphery of the cam inner cylinder 14 and moves the first group lens frame 12 and the second group lens frame 22 as described above. The rotating plate 62 rotates at the same time, and from the photo interrupter 63 that detects the light shielding blades of the rotating plate 62, a pulse signal (pulse signal of 4 pulses per rotation of the rotating plate 62) according to the rotation of the rotating plate 62. Is output. By counting this pulse signal with a counter (not shown), the rotation amount of the cam cylinder 16 can be detected.
[0016]
Since the iris unit 40 is disposed on the second group lens frame 22, it moves in the lens barrel together with the first group lens frame 22 (correction system lens 20). Since the aperture hole formed on the aperture plate 42 is positioned on the optical axis of the lens, the optical axis L and the rotation center 42A of the aperture plate 42 are deviated. On the other hand, the optical axis of the lens and the center of the lens barrel usually coincide with each other. In this case, in order to make the iris unit 40 movable as described above, it is necessary to increase the inner diameter of the lens barrel. There is.
[0017]
Therefore, in the present embodiment, the center C of the lens barrel and the optical axis L of the lens are shifted. That is, the lenses and the iris unit 40 are arranged in the lens barrel so that the center C of the lens barrel is positioned at the center between the optical axis L and the rotation center 42A of the diaphragm plate 42. This minimizes the inner diameter of the lens barrel and makes the lens barrel compact.
[0018]
Next, a method for detecting the zoom position of the zoom lens will be described.
As shown in FIG. 2, a code plate 18 is disposed on the outer periphery of the cam cylinder 16, and five brushes 19 that are in contact with the code plate 18 are disposed at predetermined positions facing the code plate 18. Has been.
FIG. 3 is a development view showing details of the code plate 18. When the cam cylinder 16 is rotated, the code plate 18 moves with respect to the brush 19. Accordingly, the rotation position (that is, the zoom position) of the cam cylinder 16 can be detected based on the code signals (CODE 0 to 3) output from the brush 19. In the present embodiment, when it is detected that the zoom lens has reached the predetermined zoom position, the zoom motor 61 is braked to stop the cam cylinder 16, but the cam cylinder 16 is stopped until the cam cylinder 16 stops. 16 overruns. The overrun amount is measured by counting the pulse signals output from the photo interrupter 63 of the motor rotation detection unit described above. An accurate zoom position is detected by adding the overrun amount to the zoom position detected by the code signal.
[0019]
FIG. 4 is a view showing a positional relationship between the stopper 72 that limits the rotation range of the cam cylinder 16 and the cam cylinder 16. The stopper 72 is fixed on the base plate 72 (FIG. 2), and is inserted into a recess 16B formed on the inner peripheral surface of the cam cylinder 16. As a result, the cam cylinder 16 rotates within a range in which the concave portion 16 </ b> B contacts the stopper 72. Further, the rotation range of the cam cylinder 16 and the detection range of the code plate 18 shown in FIG. 3 correspond one-to-one, and immediately before the cam cylinder 16 comes into contact with the stopper 72, the code plate 18 Either one of the code patterns (0000) and (1000) indicating the formed both end positions is detected by the brush 19. The cam cylinder 16 is controlled to stop so as not to come into contact with the stopper 72. However, when the control system of the cam cylinder 16 runs out of control, the cam cylinder 16 is stopped by the stopper 72, and the stop position is detected by the brush 19. It can be done.
[0020]
FIG. 5 is a diagram showing the relationship between the zoom drive command for controlling the zoom lens and the code plate. There are six types of zoom drive commands: POWER ON, POWER OFF, MACRO ON, MACRO OFF, WIDE ZOOM, and TELE ZOOM.
FIG. 6 is a rear view of the camera 100. On the rear side, a power ON switch 80, a switch 82 for performing MACRO ON and MACRO OFF, and a zoom switch 84 for performing WIDE ZOOM and TELE ZOOM are provided.
[0021]
The release switch 86 is a two-stage switch that turns on the switch S1 when half-pressed and turns on the switch S2 when fully pressed. When the switch S1 is turned on, preparations for photographing such as focus adjustment and iris control, and reverse control described later are performed. When the switch S2 is turned on, the shutter is released and the subject is photographed.
[0022]
In FIG. 2, the zoom lens is a retractable zoom lens in which a lens barrel is housed in the body of the camera 100 when shooting is not performed. Further, the variable power lens 10 as the first group lens is a lens having negative power. Accordingly, when the zoom lens is zoomed in the wide direction, the first group lens frame 12 (variable lens 10) is extended, and when zooming in the tele direction, the first group lens frame 12 (variable system). The lens 10) is retracted.
[0023]
Further, the focus adjustment is performed by an autofocus device that measures the shooting distance by a triangulation method and moves the focus lens 30 to a focus position based on the distance measurement value. Since the focus lens 30 is located behind the variable magnification lens 10 and the correction lens 20, in order to accurately control the focus lens 30 to a focus position, the variable magnification lens 10 and It is necessary to detect an accurate position of the correction system lens 20 (that is, an accurate zoom position).
[0024]
Next, an outline of zoom lens control based on each zoom drive command will be described.
As shown in FIG. 5, when POWER ON is accepted as a zoom drive command, the zoom lens is moved from the retracted position to a predetermined zoom initial position. Here, the predetermined initial zoom position is an intermediate position between the wide end and the zoom end. On the other hand, when POWER OFF is received when the zoom lens is at an arbitrary zoom position, the zoom lens is moved to the retracted position.
[0025]
When the zoom lens is at an arbitrary zoom position and MACRO ON is received, the zoom lens is moved to the wide end. As a result, a macro shooting mode capable of macro shooting is set, and zooming by the zoom switch 84 is prohibited. Note that the zoom lens does not move even if MACRO OFF is received in macro shooting mode. That is, even if the zoom lens receives MACRO OFF, it does not automatically return to the zoom position when MACRO ON is received. However, since the macro shooting mode is canceled, zooming by the zoom switch 84 becomes possible.
[0026]
  Further, when WIDE ZOOM is received by operating the zoom switch 84 when the zoom lens is at an arbitrary zoom position between the tele end and the wide end, the zoom lens moves in the wide direction during the reception period of this command. When the zoom switch 84 is turned off, the zoom lens stops after the zoom position is switched by one step in the wide direction. On the other hand, when the zoom lens is in an arbitrary zoom position, if TELE ZOOM is received by operating the zoom switch 84, the zoom lens moves in the tele direction during the command reception period, and the zoom switch 84 is turned OFF. The zoom lens switches the zoom position one step in the tele direction.After this, when the release switch 86 is pressed halfwayThen, the zoom direction is reversed and the movement in the wide direction is started (reverse), and the zoom position is stopped after the zoom position is switched by one step.
[0027]
That is, when the zoom lens is stopped in the zoom range from the tele end to the wide end, it is stopped when moving in the wide direction. Thereby, the zoom position of the zoom lens can be accurately detected.
Next, the operation of the zoom lens described above will be described in detail with reference to FIG.
The camera 100 according to the present embodiment controls the operation of the zoom lens by executing an interrupt routine shown in FIG. 7 every 5 mS.
[0028]
First, when the interrupt routine shown in FIG. 7 is started by the timer interrupt, it is determined whether or not the zoom operation is being performed (step S10). Here, “during zoom operation” means a state in which a drive signal is output to the zoom motor 61 based on a zoom drive command. If the zoom operation is not being performed, it is determined whether or not the zoom motor 61 is braked (step S12). If the brake is not applied, it is determined whether or not the zoom is stopped (step S14). When the zoom is stopped, the interrupt routine is terminated. When the zoom is not stopped, error processing is performed (step S16), and the interrupt routine is terminated. Note that “braking” means a state where a brake signal is output to the zoom motor 61, and “stopping a zoom” means a state where no signal is applied to the zoom motor 61.
[0029]
If it is determined in step S10 that the zoom operation is being performed, it is determined whether or not the zoom position has changed from the current zoom position based on the code signals (CODE0 to CODE3) output from the brush 19 (step S18). ). If no change in the zoom position is detected, the switching halfway flag is cleared (step S20), and the interrupt routine is terminated. The operation of the switching halfway flag will be described later.
[0030]
On the other hand, if a change in the zoom position is detected in step S18, it is determined whether or not a switching flag is set (step S22). If the switching halfway flag is not set, the switching halfway flag is set (step S24), and then the interruption routine is terminated. If the switching halfway flag is set, the current zoom is set. The position is updated (step S26). In other words, in order to update the zoom position, it is necessary to set a switching flag during the processing of the previous interrupt routine. In other words, the interruption routine process starts again 5 ms after the change in the zoom position is detected. If the change in the zoom position is detected again at this time, the zoom position is updated. This is to prevent erroneous detection of the zoom position due to chattering.
[0031]
When the zoom position is updated in step S26, it is determined whether the updated zoom position is the stop position or the stop request flag is turned on (step S28). Here, the zoom position is the stop position, for example, when the zoom drive command is POWER ON as shown in FIG. 5, the intermediate position between the tele end and the wide end is the stop position, and the zoom drive command is MACRO ON. In this case, the wide end is the stop position. The stop request flag is turned on when the zoom switch 84 is turned off.
[0032]
If it is determined in step S28 that the updated zoom position is not the stop position and the stop request flag is not turned on, the switching routine flag is cleared (step S30), and then the interrupt routine is terminated. Thereby, the zooming operation is continued.
On the other hand, when it is determined in step S28 that the updated zoom position is the stop position or the stop request flag is turned on, the process proceeds to a process for stopping the zoom lens. Here, the stop control differs depending on whether the zoom direction of the zoom lens is the tele direction or the wide direction. That is, if it is determined in step S32 that the zoom direction is not the tele direction (wide direction), the counter for counting the brake time is set to 0, the brake signal is output to the zoom motor 61 and the overrun amount is measured. And the interrupt routine is terminated (step S34). The overrun amount is measured by counting the pulse signals output from the photo interrupter 63 (see FIG. 2) of the motor rotation detection unit as described above.
[0033]
When the process of step S34 is completed, the interrupt routine starts again after 5 mS. In this case, it is determined in step S10 that the zoom operation is not being performed, and the process proceeds to step S12, where it is determined whether or not braking is being performed. Since the brake is applied in step S34, the process proceeds to step S36, where it is determined whether or not the counter value of the counter for counting the brake time is 15 or more. Since the current counter is 0 (because the counter is set to 0 in step S34), the process proceeds to step S38, where the counter is incremented by 1 and the interrupt routine is terminated.
[0034]
In this way, the interrupt routine that goes through step S10, step S12, step S36, and step S38 is repeated 15 times, and when the 16th interrupt routine starts and moves to step S36, the counter value of the counter becomes 15. Therefore, the process proceeds to step S40. It should be noted that 80 mS (= 5 mS × 16) has elapsed from when the brake is applied in step S34 until the process proceeds to step S40. That is, after applying the brake in step S34, the process proceeds to step S40 after 80 mS. In step S40, the overrun amount is measured until 80 mS elapses after the brake is applied in step S34. At this time, the zoom is stopped and the brake signal to the zoom motor 61 is turned off (step S42). As a result, when the interrupt routine starts thereafter, the interrupt routine is terminated via steps S10, S12, and S14.
[0035]
  On the other hand, when it is determined in step S32 that the zoom direction is the tele direction, the zoom direction flag is set to “TELESet to "(Step S33), The counter for counting the brake time is set to 0, the brake signal is output to the zoom motor 61, the measurement of the overrun amount is started, and the interruption routine is ended (step S34). On the other hand, the zoom direction iswideDetermined to be directionAndProceeding to step S34, processing for stop control is executed.
[0036]
Here, a zooming operation when the zoom switch 84 is turned off after the zoom switch 84 is operated in the tele direction will be described in detail with reference to FIG. In the figure, (1) when the zoom switch 84 is turned OFF, (2) the zoom position is switched, and (3) when the chattering prevention time has passed (steps S18, S22, S24 in FIG. 7), the zoom The position is updated (step S26). Subsequently, after the determination in step S28 and step S32 is performed, (4) the zoom direction is reversed (step S36).
[0037]
When the zoom direction is reversed and the zoom operation in the wide direction is performed, the zoom position is again switched, and when the time for preventing chattering has elapsed (6), the zoom position is updated (step S26). Subsequently, after the determination in step S28 and step S32 is performed, (7) the zoom motor is braked (step S34), and after the 80 mS brake is applied as described above, the overrun amount is measured.
[0038]
The zoom position of the zoom lens is output from the code signal (zoom position) output from the five brushes 19 in contact with the code plate 18 and from the photo interrupter 63 of the motor rotation detection unit after the zoom position is switched. It is accurately detected from the amount of overrun obtained by counting the pulse signal.
Then, the focus lens 30 is automatically moved to a focus position based on the zoom position detected in this way and the shooting distance measured by the triangulation method.
[0039]
Next, reverse zoom lens control by half-pressing the release switch 86 will be described.
When the release switch 86 is half-pressed and the switch S1 is turned on, the interruption routine shown in FIG. 9 starts, and first, it is determined whether or not the zoom direction flag of the zoom lens is “TELE” (step S50). If the zoom direction flag is not “TELE”, the process proceeds to step S64, and normal shooting preparation such as distance measurement of the shooting distance is performed.
[0040]
On the other hand, if the zoom direction flag is “TELE”, the zoom is driven in the wide direction (step S52), and the down-count of the overrun amount measured in step S40 in FIG. 7 is started (step S54). Thereafter, it is determined whether or not the predetermined amount is counted down (step S56). Here, the predetermined amount of downcount corresponds to the amount of rotation of the zoom motor 61 within a range in which the zoom lens stopped during movement in the tele direction actually moves in the wide direction and the zoom position does not change.
[0041]
When the overrun amount is counted down by a predetermined amount, a brake signal is output to the zoom motor 61 for a certain period (step S58). Subsequently, the overrun amount is measured and the zoom direction flag is set to “WIDE” (step S60). Step S62).
Thereafter, the process proceeds to step S64, and normal shooting preparation such as distance measurement of the shooting distance is performed. When the zoom direction flag is “TELE”, the code signals (zoom positions) output from the five brushes 19 that contact the code plate 18 and the overrun amount measured in step S60 are accurate. Detect the zoom position. Then, the focus lens 30 is automatically moved to a focus position based on the zoom position detected in this way and the shooting distance measured by the triangulation method. Thereafter, the release switch 86 is fully pressed to photograph the subject.
[0042]
As described above, in the camera 100 according to the present embodiment, when the release switch 86 is half-pressed, that is, when the actual photographing is performed, the zoom lens reverse control is performed, so that driving energy can be saved. .
In addition, since the camera 100 performs reverse control when the release switch 86 is half-pressed, the camera 100 is easier to use than a conventional camera that performs reverse control each time the zoom switch is turned off. is there.
[0043]
In the present embodiment, the reversing control is performed when the release switch 86 is half-pressed. However, the present invention is not limited to this, and before the release switch 86 is half-pressed and fully pressed. Reverse control may be performed. That is, reverse control may be performed after AE and AF are performed by half-pressing operation, or reverse control may be performed by operating the switch after the release switch 86 is half-pressed by a switch different from the release switch 86. .
[0044]
Further, when the backlash is in a specific direction, the reverse control may be performed after the release switch 86 is half-pressed without overrun.
On the other hand, some conventional cameras perform reverse control after the release switch is fully pressed and before focus driving (Japanese Patent Laid-Open No. 2-201306). Compared with this type of camera, the camera according to the present embodiment performs reverse control at the time of half-press operation, so that the time lag at the time of shutter release can be shortened.
[0045]
【The invention's effect】
As described above, according to the camera of the present invention, when the release switch is half-pressed, that is, when the actual shooting is performed, the zoom lens is controlled so that the zoom lens is moved back. Compared with the conventional apparatus which performs this, it is possible to save driving energy.
[Brief description of the drawings]
FIG. 1 is a front view of a camera according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view of a zoom lens device.
FIG. 3 is a development view showing details of the code plate.
FIG. 4 is a diagram showing the positional relationship between a stopper and a cam cylinder that limit the rotation range of the cam cylinder.
FIG. 5 is a diagram illustrating a relationship between a zoom drive command and a code plate.
6 is a rear view of the camera shown in FIG.
FIG. 7 is a flowchart for explaining the operation of the zoom lens;
FIG. 8 is a flowchart for explaining the operation of the zoom lens;
FIG. 9 is a flowchart for explaining an interrupt routine;
[Explanation of symbols]
10 ... Variable lens
20. Correction lens
30 ... Focus lens
86 ... Release switch
100 ... Camera

Claims (1)

A zoom lens,
A zoom switch for indicating a zoom position of the zoom lens;
A zoom lens driving mechanism for moving the zoom lens by operating the zoom switch;
A release switch that can be fully pressed and half pressed;
When the zoom lens moves and stops in a predetermined direction out of the telephoto direction and the wide direction of movement of the zoom lens and the release switch is pressed halfway, or the release switch is pressed halfway A control unit that reversely controls the zoom lens drive mechanism to stop after the zoom lens has moved by a predetermined amount in the other direction before being fully pressed ,
The reversing control by the control unit is performed based on a rotation amount of a zoom motor in a range in which a zoom lens stopped during movement in one direction moves in another direction and the zoom position does not change. .

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