JP2007057678A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform control to transit to a power saving state without producing noise when transiting to the power saving state in automatic exposure control. <P>SOLUTION: The cause of power generation is due to the fact that the power source of a driving circuit is turned off when switching to a power saving mode as shown in figure 4 that. Therefore, when switching to the power saving mode, the power source is not directly turned off but a control method for controlling diaphragm/ND being a part of the automatic exposure control is changed. Thus, the sound is prevented from being produced by turning off the power source of the driving circuit after intentionally performing close control as control shown in figure 5, for example. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control method for aperture control and ND filter control which is automatic exposure control in an imaging apparatus such as a digital camera or digital video camera.

In the conventional automatic exposure control, when the camera shifts to the VTR mode / card playback mode, a photographed image of the camera is not required. Therefore, control for entering the power saving mode such as turning off the camera photographing system is performed. In addition, when there is no need for current shot images such as REC search and REC review in camera shooting mode, electromagnetic noise is generated from the motor system of the aperture / ND filter, which adversely affects the REC search and REC review images. In order to avoid this problem, control for turning off the driving power source such as an aperture / ND filter is performed. As for the control when the power is turned off, as shown in Japanese Patent Laid-Open No. 2000-66260, in the shift lens control, the current lens position is detected, and the control method is changed based on the result.
JP 2000-66260 A

  In conventional automatic exposure control, automatic exposure control is also switched to power save mode when the current shot image such as VTR mode, REC search, REC review, and power OFF is not required. The power of the motor drive circuit such as the ND filter is turned off. Therefore, if the motor drive circuit is suddenly turned off, as shown in FIG. 4, the diaphragm (ND filter) moves in the closing direction vigorously and hits the mechanical end by the force of the spring or magnet, generating noise. There was a problem of degrading the quality.

  An object of the present invention is to improve the above-mentioned drawbacks and to enable control in which the aperture or the ND filter makes a transition to the power saving state without generating noise when the automatic exposure control makes a transition to the power saving state.

  As a means for solving the above problem, the cause of the sound is that the power of the motor is turned off when switching to the power saving mode. Therefore, instead of turning off the drive circuit power immediately when switching to the power save mode, the aperture / ND filter control of the automatic exposure control is changed, and the aperture is intentionally closed, for example, as in the control example shown in FIG. Then, the motor drive circuit power supply is turned off and the generation of sound is prevented.

  By performing aperture control and ND filter control using this control method, it is possible to enter the power save mode and realize energy saving, and at the same time, shift to the power save mode without generating sound and degrading quality.

  Embodiments of the present invention will be described below with reference to configuration diagrams and flowcharts.

  FIG. 1 is a schematic configuration diagram of an image pickup apparatus that implements the present invention. An optical signal from the subject image enters through the imaging optical system 1 and the incident light amount is adjusted by the diaphragm 2 and the ND filter 6 that adjust the incident light amount. Then, after the photoelectric conversion is performed by the CCD 10 and the signal level is adjusted by the double correlation sampling circuit / AGC circuit 12 as an electric signal, the data is passed to the digital signal processing circuit 14 by the A / D conversion 13 as digital data. The video signal is signal-processed by the digital signal processing circuit 14 based on the contents instructed by the microcomputer 16 and is recorded on the recording medium 15 at the time of recording. In the imaging apparatus, such a normal operation is performed. However, the microcomputer 16 detects a button operation or the like from the user by the button operation / mode detection circuit 17 and changes to the mode when the operation information is received. Take control. In the prior art, the button operation / mode detection circuit 17 detects the power saving mode and what button operation is performed, and notifies the microcomputer. The microcomputer 16 issues a command to make a transition to the power save mode. Particularly in the exposure control, the power saving is realized by stopping the power supply to the aperture mechanism control circuit 4 and the ND filter control circuit 8.

  At this time, if the power supply is stopped immediately, the diaphragm moves in the closing direction and the ND filter operates in the retracting direction, and the mechanical end vigorously emits a sound. Therefore, in the present invention, when the power saving mode is entered, Does not immediately stop the power supply to the drive circuit, but issues a command to the exposure control method changing circuit 18 by the microcomputer 16 to change the aperture / ND filter control, and gradually, as in the control example shown in FIG. Control is performed to close the aperture and gradually retract the ND filter (not shown). Here, the control example is shown in FIG. 5. However, the gradual control here is not limited to the control at a uniform speed, but the control is divided into two stages, and the control is performed at a high speed immediately after the start of the closing operation, and at a low speed near the closing. It includes a control method for controlling (hereinafter referred to as “gradually”). When it is determined that the control is finished, the fact is transmitted to the exposure control method change cancel circuit 19, and the exposure control method change cancel circuit 19 causes the diaphragm mechanism control circuit 4 and the ND filter control circuit 8 to pass through the microcomputer 16. By stopping the power supply, it is possible to shift to the power save mode without generating noise.

  Next, the control during the power save mode transition of the first embodiment will be described with reference to the flowchart of FIG. FIG. 2 is a flowchart for explaining details of the operation of the control unit.

  First, when this flow is started, it is determined in step S1 whether a power save request from the microcomputer 16 has been issued. Here, if the power save request is not issued and the answer is “NO”, the detection process is repeated until the power save request is issued without performing the special process while maintaining the normal operation. If a power save request is detected and the determination is “YES”, the process proceeds to step S2.

  In step S2, the current position of the aperture / ND filter is detected by a sensor signal, a difference from a predetermined closed position is calculated, and the process proceeds to step S3.

  In step S3, the speed at which control is performed from the difference data calculated in step S2 to the closing is calculated, and the process proceeds to step S4.

  In step S4, control is performed in the closing direction and the ND filter in the retracting direction based on the data calculated in step S3, and the process proceeds to step S5.

  In step S5, it is determined whether or not the aperture is completely closed and whether or not the ND filter is completely retracted. If "NO" is determined here, the process returns to step S2 to perform feedback. If “YES” is determined, the microcomputer 16 is notified of power saving OK, and the power supply to the diaphragm mechanism control circuit 4 and the ND filter control circuit 8 is stopped through the microcomputer 16.

  Thus, after receiving the power save request, the aperture is gradually closed, the ND filter is controlled to be retracted, the power supply to the drive circuit is stopped, and the power save is performed, so that power can be generated without generating noise. Save can be realized.

  FIG. 1 is a schematic configuration diagram of an image pickup apparatus that implements the present invention. This figure has the same configuration as that of the first embodiment, and is different from the first embodiment in that the timer counter 20 is used. Since the operation of the imaging apparatus is the same as that of the first embodiment, a description thereof will be omitted.

  Here, as in the first embodiment, in the prior art, in the normal operation state, the button operation / mode detection circuit 17 detects whether the power saving mode or the button operation has been performed, and notifies the microcomputer. The microcomputer 16 issues a command to make a transition to the power save mode. Particularly in the exposure control, the power saving is realized by stopping the power supply to the aperture mechanism control circuit 4 and the ND filter control circuit 8.

  At this time, if the power supply to the drive circuit is stopped immediately, the diaphragm operates in the closing direction and the ND filter operates in the retracting direction, and the mechanical end is violently generated and generates noise. Therefore, in the present invention, the power supply to the drive circuit is not stopped immediately when the mode is changed to the power save mode, but the aperture / ND filter control is changed by the exposure control method changing circuit 18 as in the first embodiment. Then, the control is performed so that the aperture is gradually closed and the ND is retracted. When it is determined that the control is finished, the exposure control method change canceling circuit 19 notifies the exposure control method change canceling circuit 19 to that effect. Control is performed to stop the power supply of the diaphragm mechanism control circuit 4 and the ND filter control circuit 8 through the microcomputer 16. However, when this control is performed faithfully, if an interrupt process or a processing error occurs during the control from step S2 to step S5, it may take a very long time or the process cannot be escaped. May occur. For this reason, the second embodiment has the flow of the first embodiment, and at the same time, when a power save request is received, the timer counter starts counting, and when it is counted for a certain period of time, the flow of the aperture is closed and the ND filter is saved. Even if it is not completed, a power save ON command is forcibly issued, to that effect, the power supply to the aperture mechanism control circuit 4 and the ND filter control circuit 8 is stopped through the microcomputer 16 and the mode is changed to the power save mode. .

  Next, regarding the control at the time of the power save mode transition of the second embodiment, a control flow will be described using the flowchart of FIG. FIG. 3 is a control flowchart of the second embodiment of the imaging apparatus according to the present invention. From step S1 to step S6, the same control flow as in the first embodiment is performed, so the same reference numerals are used and detailed description thereof is omitted.

  First, in FIG. 3, in the second embodiment, when the power saving request condition determination in step S1 is determined to be YES, the process proceeds to step S2 and proceeds to step S7 simultaneously with the same flow as in the first embodiment.

  In step S7, a count function such as a timer counter is activated and started, and the process proceeds to step S8. In step S8, the counter is incremented and the process proceeds to step 9. In step 9, it is determined whether or not a lapse of time exceeding a certain count value has been achieved. If the predetermined time has not elapsed and the condition is determined as “NO”, the process returns to step S8 and further counts up. If the predetermined time has elapsed and the condition determination is “YES”, the process proceeds to step S6 regardless of the operation completion determination in step S5. In step S6, the microcomputer 16 is notified of power saving OK, and the power supply to the diaphragm mechanism control circuit 4 and the ND filter control circuit 8 is stopped through the microcomputer 16. When the power supply is stopped, the control according to the present invention is completed. As described above, after receiving a power save request, by observing the passage of a certain time and forcibly stopping the power supply when a certain time has elapsed, the power error is performed and the power saving is performed. It is possible to prevent the mode transition time from being prolonged or the state incapable of mode transition due to embedding processing or the like, and to smoothly transition to the power save mode.

FIG. 3 is a block diagram showing a configuration of first and second embodiments of the imaging apparatus according to the present invention. The flowchart which shows the control operation | movement flow of 1st Example of this invention. The flowchart which shows the control operation | movement flow of the 2nd Example of this invention. The figure which showed the operation | movement of the problem occurrence used as the subject of this invention. The figure which showed the operation example which solves the subject of this invention.

Explanation of symbols

1 lens (lens group)
2 Aperture Mechanism 3 Aperture Drive Motor 4 Aperture Drive Circuit 5 Aperture Position Detection Sensor 6 ND Filter 7 ND Filter Drive Motor 8 ND Filter Drive Circuit 9 ND Position Detection Sensor 10 CCD
11 CCD drive circuit 12 CDS / AGC
13 A / D
DESCRIPTION OF SYMBOLS 14 Digital signal processing circuit 15 Recording medium 16 Microcomputer 17 Button operation and mode detection circuit 18 Exposure control method change circuit 19 Exposure control method change cancellation circuit 20 Timer counter

Claims (2)

Means for detecting whether the mode / state does not use a camera image;
Means for determining whether to switch to the power saving mode according to the result;
Means for switching to the power save mode according to the judgment result;
In an imaging apparatus having means for detecting the current positions of the diaphragm and ND filter and means for controlling the positions of the diaphragm and ND filter,
When shifting to the power save mode, the diaphragm / ND filter drive circuit is not suddenly turned off, but the diaphragm is gradually closed and the ND filter is controlled to the retract side, and the diaphragm / ND filter is controlled to the mechanical end. An image pickup apparatus characterized in that the power source of the driving circuit for the diaphragm / ND filter is turned off after it has been determined that the drive has been performed. Means for detecting whether the mode / state does not use a camera image;
Means for determining whether to switch to the power saving mode according to the result;
Means for switching to the power save mode according to the judgment result;
In an imaging apparatus having means for detecting the current positions of the diaphragm and ND filter and means for controlling the positions of the diaphragm and ND filter,
When shifting to the power saving mode, the diaphragm / ND filter drive circuit is not suddenly turned off, the diaphragm is gradually closed and the ND filter is controlled to the retract side, and the diaphragm / ND filter is controlled to the mechanical end. Or after a certain amount of time has elapsed from when a power save request is issued, whichever comes first, and after that detection, the drive circuit of the aperture / ND filter is turned off. An imaging device that is characterized.

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