JP4133500B2 - Mirror open / close detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a mirror open / close detection device applied to a single-lens reflex camera back in which a replaceable camera back is mounted on the rear part of the camera, and in particular, an image sensor is disposed on an imaging surface of a medium format camera back, and a signal For a camera equipped with a digital still back to obtain image data by processingIt is related.
[0002]
[Prior art]
Medium format digital cameras are equipped with a digital still back. The digital still back has a built-in function for obtaining an image by attaching an image pickup system of a digital camera to a camera back portion on which a film is loaded, converting incident light into an image pickup signal, and performing digital signal processing on the image pickup signal. . When the digital still back is mounted on the camera body, it is required to manage the relative positions of the two with high accuracy. By this management, the image pickup surface of the image pickup apparatus disposed in the digital still back is matched with the image formation surface of the lens system (see Patent Document 1). Further, when the entire digital still back is moved in response to tilt shooting, there is a problem that the tilt mechanism of the camera becomes large (see Patent Document 2).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-133264
[Patent Document 2]
JP-A-9-331475.
[0004]
[Problems to be solved by the invention]
By the way, there is one that constructs a medium format digital camera system by attaching a general-purpose digital still back to a medium format type digital camera body. Compared to a general-purpose stillback for a silver halide film medium format camera, the general-purpose stillback for a silver halide film only needed to obtain the shutter opening / closing timing. In addition to this, it is also required to control a plurality of circuit operation timings including, for example, power on / off, with high accuracy.
[0005]
A general-purpose digital still back can be used for any type of camera in this way, but it can manage various operation timings, etc., even though the connection with the camera body is not in a dedicated combination relationship. It is required and cannot be managed with high accuracy. In other words, this problem with medium format cameras equipped with a general-purpose digital still back is that communication between the camera body and the digital still back is performed compared to a dedicated medium format digital camera or a single-lens reflex digital camera. It is a big problem that it is not known. For this reason, a medium-format camera equipped with a general-purpose digital still back cannot accurately know the timing of operating the release shutter in the camera body, etc., with the digital still back. Therefore, a medium format camera equipped with a general-purpose digital stillback predicts an arbitrary time from this operation timing as a delay time, and calculates the shutter timing based on the first method for operation and the sync signal of the external flash control signal. The exposure is performed by the second method.
[0006]
However, in the first method, the operation timing of the mirror opening / closing mechanism that operates the lens shutter or the focal plane shutter varies depending on the operation timing. Since this variation cannot be determined, shooting is performed by supplying incident light to the imaging unit for a time longer than the actual shutter timing to receive (exposure or imaging). In such a state, dark current flows for a long time. Accordingly, such a light reception setting increases noise due to dark current in the obtained imaging signal and degrades the image.
[0007]
In the second method, when the synchro signal is used as a trigger, the medium format camera initializes the imaging unit after the flash light emission signal is output. Therefore, when the high-speed shutter requested by the user is driven, the light reception timing when the shutter is opened cannot be synchronized with the timing at which the imaging unit can receive light. As a result, the medium format camera has a problem that a dark screen is captured instead of a subject image desired by the user. This is not limited to general purpose, and the actual light control is performed by the mechanical parts, so the variation in operation timing is very large, even with dedicated cameras due to external factors such as temperature and humidity. It is known to change significantly.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide a mirror open / close detection device that eliminates the disadvantages of the prior art and that can be accurately exposed in accordance with the shutter operation of a camera body using a general-purpose camera back.
[0009]
It is another object of the present invention to provide a volume change detection device that can eliminate such drawbacks of the prior art and detect a change in volume caused by a partitioning operation for partitioning a certain volume.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a finder means for confirming an optical image from the optical system, and an optical system for forming an incident light from the object field on the focal plane. The camera body is equipped with a movable mechanism with a mirror that can be sent or moved in either direction of the camera back, which has a light imaging and recording function, and selects the shooting timing for the desired scene in the object field. In response to the operation of the operation means, the camera back detects which position the mirror is in, and the camera body in the camera body obtained by this detection is provided. An opening / closing detection means for determining a spatial state and controlling the functional operation of the camera back is included.
[0011]
The mirror open / close detection device of the present invention is provided with an open / close detection means on the camera back, and drives the movable mechanism in conjunction with the operation of the operation means, and what is the position state of the mirror accompanying this drive? By detecting and determining the spatial state from this detection, it is possible to accurately know the operation timing of the mirror, and by controlling the functional operation of the camera back according to this timing, the operation and the functional operation of the camera back A desired scene can be captured while suppressing delays and timing variations that occur during
[0012]
In order to solve the above-described problems, the present invention is provided with a variable volume mechanism for changing the volume of the casing in the measurement target casing, and the volume change in the casing due to the operation of the variable volume mechanism. In the volume change detection device to be measured, the volume change in the housing is detected according to the movement of the operating means for operating the variable volume mechanism and the partition member attached as a part of the variable volume mechanism in conjunction with this operation. And a state determination means for determining the state of the casing obtained by the detection.
[0013]
The volume change detection device according to the present invention includes a variable volume mechanism in a measurement target casing, and changes the volume in the casing by moving the partition member in conjunction with the operation of the operation means. By detecting with the determination means and determining the state, the state of the housing can be known.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a mirror open / close detection device according to the present invention will be described in detail with reference to the accompanying drawings.
[0015]
In the present embodiment, the mirror open / close detection device of the present invention is applied to a camera back exchangeable medium format digital camera 10. The illustration and description of parts not directly related to the present invention are omitted. In the following description, the signal is indicated by the reference number of the connecting line in which it appears.
[0016]
A plan view of the digital camera 10 as viewed from above is shown in FIG. As shown in FIG. 2, the digital camera 10 includes an optical system 12, a camera body 14, and a camera back 16. The digital camera 10 is provided with a replaceable optical system 12 in the camera body 14. Although not shown, the optical system 12 is provided with a stop lever for the user to adjust the aperture value obtained by AE (Automatic Exposure) photometry. The optical system 12 is provided with a diaphragm mechanism in which a diaphragm value is given to a diaphragm display window for setting a diaphragm value by the lever, and an incident light beam is narrowed in accordance with the setting. The lever sets the aperture value in the optical system 12 in conjunction with the aperture mechanism and the aperture value of the aperture display window.
[0017]
Some digital cameras have an accordion between the optical system 12 and the camera body 14 although not shown. In such a digital camera, the optical system 12 and the bellows are fixed by a frame. The frame has a lens lock mechanism and a hot shoe to which a flash lamp is attached. Some of the frames are formed so as to pass through focusing rails extending from the lower part of the camera body 14.
[0018]
In this case, the focus adjustment is performed by moving the frame on the rail in accordance with the optical image formed on the finder at the top of the camera body 14. This frame has a lock mechanism for fixing the frame at a user's desired focus position (focus position).
[0019]
In addition to the manual focus adjustment described above, the digital camera 10 may have an AF (Automatic Focus control) adjustment function and a lens shutter.
[0020]
The camera body 14 includes a finder 18 and a hood 20 as shown in FIG. The finder 18 is provided with a focusing screen for forming an image of incident light that has passed through the optical system 12. The hood 20 also has a function of protecting the finder 18. The hood 20 is also of a foldable type that has a high hermetic seal so that the surrounding light is shielded so that the image can be easily viewed and fine focusing is facilitated. In addition, although not shown, the camera body 14 is provided with, for example, a shutter speed dial, a mirror up / down switch, a release shutter button, a sync test button, a sync socket, a communication connector for communicating with an external device, etc. Yes.
[0021]
The camera back 16 is provided with a photographing / recording circuit 22 having a signal processing function and a recording function related to photographing, and an LCD (Liquid Crystal Display) having an image display function (not shown). The imaging / recording circuit 22 includes an imaging unit 24 that captures incident light and a recording / signal processing unit 26, as will be described later. The LCD is disposed on the back side of the camera back 16 and displays an image formed according to the RGB data supplied from the recording / signal processing unit 26.
[0022]
In the imaging unit 24, light receiving elements that convert incident light that has passed through the camera body 14 into electrical signals (that is, photoelectric conversion) are two-dimensionally arranged. The imaging unit 24 uses either a CCD (Charge Coupled Device) type or a C-MOS (Complementary-Metal Oxide Semiconductor) type. The imaging unit 24 outputs an imaging signal obtained by imaging to the recording / signal processing unit 26.
[0023]
The recording / signal processing unit 26 performs gamma correction, white balance adjustment, and the like on the obtained imaging signal, and records it in a storage (not shown) according to the mode set in the digital camera 10. The recording / signal processing unit 26 performs matrix processing, compression processing, reproduction processing, and the like as signal processing on the imaging signal according to the mode.
[0024]
The camera back 16 is preferably provided with a focal plane shutter so as to protect the imaging unit 24 on the incident light side. The shutter only needs to have one of a lens shutter and a focal plane shutter.
[0025]
The camera back 16 is connected to the camera body 14, but cannot communicate with the camera body 14 because the camera back 16 is general-purpose and detachable. Therefore, the camera back 16 newly includes a mirror operation detection circuit 28 so that the operation timing of the mirror can be obtained without using communication means.
[0026]
As shown in FIG. 1, the mirror operation detection circuit 28 includes a signal emitting unit 30, a microphone 32, a state detection unit 34, and a mirror correspondence control circuit 36. The signal emitting unit 30 includes a burst pulse generation circuit 38 and an ultrasonic transmitter 40 for monitoring phase fluctuation. The burst pulse generation circuit 38 has a function of alternately generating a continuous pulse over a predetermined period and a stop period indicating a break of the pulse. The burst pulse generation circuit 38 outputs the generated burst pulse 42 to the ultrasonic transmitter 40. The ultrasonic transmitter 40 is an ultrasonic transducer that generates an ultrasonic wave according to the supplied burst pulse 42. The ultrasonic transmitter 40 is preferably disposed on the substrate surface on which the imaging unit 24 is mounted.
[0027]
The microphone 32 is a reception sensor that detects the ultrasonic wave transmitted from the ultrasonic transmitter 40. The microphone 32 may be disposed on the same side of the substrate surface as the ultrasonic transmitter 40 or at a different position as shown in FIG. Further, the ultrasonic transmitter 40 and the microphone 32 are not limited to the positional relationship shown in FIG. 1, and may be disposed in the reverse positional relationship as shown in FIG. 1 as shown in FIGS. Good. The microphone 32 converts the received ultrasonic wave into an electric signal, and outputs a burst signal 44 obtained by the conversion to the state detection unit 34.
[0028]
The state detection unit 34 includes a detection circuit 46 and a phase comparison circuit 48. The detection circuit 46 detects the burst signal 44 as an AM (Amplitude Modulation) modulated signal and supplies the obtained burst pulse 50 to the phase comparison circuit 48. The phase comparison circuit 48 is also supplied with a burst pulse 42 which is a provider of ultrasonic transmission. The phase comparison circuit 48 detects a phase difference based on the burst start timing of the burst pulses 42 and 50, and outputs a rectangular signal 52 representing a shift time corresponding to the detected phase difference to the mirror correspondence control circuit 36.
[0029]
The mirror correspondence control circuit 36 reads the time information provided by the supplied rectangular signal 52, determines the position of the mirror according to the obtained time information, and outputs the control signal 54 according to the determination result to the photographing / recording circuit 22. To supply. For example, the mirror correspondence control circuit 36 counts a period during which the rectangular signal 52 is supplied with a counter. Further, the mirror correspondence control circuit 36 may obtain the distance from the reflector by multiplying the time indicated by the phase difference by the speed of sound. At this time, the sound speed is, for example, 340 m / sec. The mirror correspondence control circuit 36 presets a threshold value for any one of the above-described counts and distances, and compares the threshold value with either one of the counts or distances supplied corresponding to the setting. Judge opening and closing. The mirror correspondence control circuit 36 generates a control signal 54 according to the determination.
[0030]
The shooting / recording circuit 22 cannot communicate between the camera body 14 and the camera back 16, but the control signal 54 supplied from the mirror operation detection circuit 28 can know the open / closed state of the mirror, and according to the open / closed state. The photographing / recording circuit 22 can be operated.
[0031]
This principle will be briefly described. FIG. 3 shows detection of the phase difference in the phase comparison circuit 48. The transmission waveform in FIG. 3 (a) is a burst pulse 42, and the reception waveform in FIG. 3 (b) is a burst pulse 50. Since the burst pulse 50 has undergone a process in which the ultrasonic waves are reflected a plurality of times within the camera body 14 and received by the microphone 32, the burst pulse 50 indicates a delay corresponding to this time, that is, the state of the space. Information appears as phase difference 56. A threshold for the phase difference is set in advance.
[0032]
As shown in FIG. 2, when cut along the fracture line IV-IV, the cross-sectional views of FIGS. 4 and 5 are obtained. Here, the arrangement positions of the ultrasonic transmitter 40 and the microphone 32 in FIGS. 4 and 5 are in the opposite positional relationship to that in FIG. The cross-sectional view of FIG. 4 shows a state in which the mirror 58 is mirrored down in the camera body 14. This mirror state is a state in which the incident light to the imaging unit 24 is shielded and the incident light is reflected by the finder 18. At this time, the ultrasonic wave emitted from the ultrasonic transmitter 40 is reflected in the space partitioned by the mirror 58 and the camera body 14. The ultrasonic path is reflected, for example, as indicated by a thick line 60 and reaches the microphone 32.
[0033]
As shown in FIG. 4, the mirror opening / closing mechanism 62 rotates in the direction of the arrow 64 in accordance with the operation of the release shutter button or the mirror up / down switch to raise / lower the mirror 58. The sectional view of FIG. 5 shows a state in which the mirror 58 is in the mirror up state. In this state, the space partitioned by the mirror 58 and the camera body 14 occupies almost the entire camera body 14, and a space that is clearly wider than the previous mirror-down state is formed. Therefore, it can be seen that the ultrasonic reflection path reaches the microphone 32 via a long distance as indicated by the thick line 60.
[0034]
This is because the phase difference 56 differs between the mirror-down state and the mirror-up state, and the phase difference is larger in the latter state than in the former. A threshold value is set so that the two states are clearly distinguished. The mirror correspondence control circuit 36 compares the supplied phase difference with a threshold value to determine the state of the mirror. When the phase difference 56 is smaller than the threshold value, the mirror is brought down, and when the phase difference 56 is equal to or larger than the threshold value, the mirror is brought up. The mirror correspondence control circuit 36 supplies a control signal 54 corresponding to these states to the photographing / recording circuit 22 to perform imaging, recording, signal processing, and the like.
[0035]
Next, the operation will be described with reference to FIG. This operation timing explains the operation of the digital camera so far. The user performs an actual imaging operation with a release shutter button (not shown). At this time, when the main imaging is performed at high speed by AE metering, a rectangular wave is formed as a trigger signal as shown in FIG. 6 (a), and the mirror 58 in FIG. 6 (b) generally starts from the rising edge of the trigger signal. It takes time T10 to upgrade. Since it is realized by a series of mechanical operations, there is almost no temporal variation.
[0036]
The delay time T12 until the release shutter (for example, the focal plane shutter) is actually operated after the mirror 58 is raised in FIG. 6B is shown in FIG. 6C. The delay time T12 falls within a very small variation of 0.05 seconds or less. The exposure shown in FIG. 6 (e) is started at the same time when the release shutter is opened. Further, when the flash sync trigger is used, the flash trigger falls after a predetermined time T14 elapses after the release shutter is simultaneously opened or opened (see FIG. 6D). For this reason, there is a possibility that the synchro trigger may not accurately expose the shutter time.
[0037]
When the shutter speed time obtained by metering the subject in advance elapses, time t_fThe release shutter closes. In response to this, the exposure of FIG. 6 (e) ends. Simultaneously with this end, reading of the signal charge accumulated in the light receiving element shown in FIG. 6 (f) is started (reading of the imaging signal). On the other hand, in the present embodiment, an accurate shutter timing can be obtained by taking in the operation of the mirror operation in FIG.
[0038]
Further, when the operation in the main imaging is performed slowly, the time until the mirror 58 opens is strictly determined, and in addition to the time T10 in FIG. 6 (b), a fluctuation time T16 is also required. . In other words, as shown in FIG. 6 (g), the mirror open state takes an extra time than the high speed by the time of the fluctuation time T16. As shown in FIG. 6 (h), the release shutter is also opened after a predetermined time T14 and further after a fluctuation time T18 has elapsed. The exposure starts at this time as can be seen from FIG. 6 (j). The flash trigger falls after the elapse of a predetermined time T14 from the start of exposure as in FIG. 6 (d) (see FIG. 6 (i)). When the release shutter in FIG. 6 (h) is closed, the exposure is completed. This time is time t_sIt is. Time t_sThereafter, as shown in FIG. 6 (k), readout of the imaging signal is immediately started. By the way, when the release shutter is closed, the variation time T20 is taken into consideration. Therefore, in order to perform exposure that satisfies both the fast (slow) and slow (slow) shutter speeds, the imaging state is maintained for a long time as in the exposure 66 shown in the lower side of FIG. 6 (l). . Of these, the actual exposure is the exposure 68, but in some cases, as described above, the exposure for the shutter time may not be possible particularly in the flash operation. The signal charge that is exposed and accumulated is the time t as shown in FIG._sIt will be read later.
[0039]
Although not shown, when the state of the mirror 58 is known as in the present embodiment, the operation at the timing based on the state of the mirror 58 becomes possible. Until now, since it is impossible to know the operation of the mirror or the like by using the general-purpose camera back 16, the variation in the mirror operation is predicted in advance and the variation is set. By applying this embodiment, variations for covering, for example, fluctuation times T18 and T20 are not required. Such a fluctuation time was set to about 0.3 to 0.5 seconds. Further, in order to cope with both exposures described above, it is not necessary to leave the imaging unit 24 in an exposed state for a long time like the exposure 66. Accordingly, noise due to dark current can be reduced. This noise reduction greatly contributes to the reduction of image quality degradation of an image obtained by imaging.
[0040]
Next, another configuration of the mirror operation detection circuit 28 provided in the camera back 16 will be briefly described. Portions common to the previous embodiment are denoted by the same reference numerals and description thereof is omitted. The basic operation of the mirror operation detection circuit 28 is the same as that shown in FIG. Here, the mirror operation detection circuit 28 in FIG. 1 detects the mirror state by phase fluctuation monitoring, but the mirror operation detection circuit 28 in FIG. 7 is different in that the mirror state is detected by spectrum fluctuation monitoring. Corresponding to this monitoring, the signal emitting unit 30 includes a modulation waveform generation circuit 70, a frequency modulation circuit 72, and an ultrasonic transmitter 40. The modulation waveform generation circuit 70 has a circuit that generates a sweep waveform such as a sine wave or a sawtooth wave. The modulation waveform generation circuit 70 outputs the generated sweep waveform signal 74 to the frequency modulation circuit 72.
[0041]
The frequency modulation circuit 72 has a function of performing frequency modulation according to the sweep waveform signal 74 supplied between the frequency f1 and the frequency f2. The frequency modulation circuit 72 supplies the frequency-modulated output signal 76 to the ultrasonic transmitter 40. The ultrasonic transmitter 40 emits an ultrasonic wave according to the supplied signal 76.
[0042]
The microphone 32 supplies the state detection unit 34 with a signal 44 obtained by converting the received ultrasonic wave into an electrical signal. The state detection unit 34 includes a demodulation circuit 78 and an envelope detection circuit 80. The demodulation circuit 78 has a function of multiplying the signal 44 and the frequency-modulated output signal 76. The output signal 76 supplied to the demodulation circuit 78 is a frequency-modulated intermediate frequency signal. The demodulation circuit 78 demodulates the signal 44 by the multiplication of the output signal 76 and supplies the demodulated signal 82 to the envelope detection circuit 80. The envelope detection circuit 80 analyzes the reflection intensity for each frequency. For the reflection intensity, for example, the demodulated wave amplitudes at the frequency f1 and the frequency f2 are obtained from the envelope. The envelope detection circuit 80 supplies the obtained amplitude data 84 for each frequency to the mirror correspondence control circuit 36.
[0043]
The mirror correspondence control circuit 36 determines the characteristics of the space formed by the camera body 14 and the camera back 16 based on the supplied data 84. The space characteristic is a total characteristic of interference due to reflection of the casing and attenuation due to absorption, and has two total characteristics in the state of the mirror 58, that is, the open state and the closed state of the formed space. The mirror correspondence control circuit 36 outputs a control signal 54 corresponding to the determination result of the space characteristics to the photographing / recording circuit 22. The photographing / recording circuit 22 is operated according to the control signal 54. At this time, since the digital camera 10 can be operated at each speed based on the state of the mirror without putting the imaging unit 24 in the imaging state for a long time, image quality deterioration can be reduced.
[0044]
In the spectrum fluctuation monitoring, a frequency-modulated signal 76 is output as a transmission waveform as shown in FIG. 8 (a). Also, the received waveform in FIG. 8 (b) represents the demodulated signal 82. The amplitudes of the frequency f1 and the frequency f2 are indicated by A and B, respectively. This amplitude includes information indicating the state of the space.
[0045]
Note that the amplitude to be obtained is not limited to the frequencies f1 and f2, but an arbitrary frequency is selected and obtained. Arbitrary frequencies are not limited to two. In this embodiment, the ultrasonic wave is used as the exploration signal for detecting the state of the space. However, the present invention is not limited to this, and infrared light that is one of electromagnetic waves may be used. When using infrared rays, it goes without saying that an infrared emitter and a light receiving element are used instead of the ultrasonic transmitter and the microphone.
[0046]
Further, in the present embodiment, the mirror operation detection circuit 28 has been described. However, in the volume change detection device, the size of the space, that is, the volume, is determined with a configuration corresponding to either the phase fluctuation monitoring or the spectrum fluctuation monitoring. Can be detected. Since the detailed description is almost the same as that of the mirror open / close detection circuit 28, it is omitted to avoid complicated description. The volume change detection device can generate not only a volume change but also a control signal according to the detection result.
[0047]
With the configuration described above, the mirror operation detection circuit 28 detects whether the mirror in the camera body 14 is opened or closed, that is, in the mirror up state or the mirror down state, without providing a communication means. Thus, the camera back 16 can know the information, and the photographing / recording circuit 22 provided in the camera back 16 can be operated on the basis of the detection timing. Thus, the photographing / recording circuit 22 does not have to be in a photographing state for a long time so that it can correspond to each operation timing so far. This suppresses the dark current generated in the shooting state, and can suppress noise generated in the image. Therefore, the digital camera 10 can be accurately exposed in accordance with the shutter operation of the camera body, and can accurately capture a desired scene and reduce image quality degradation of an image to be taken.
[0048]
The mirror operation detection circuit 28 is disposed in the camera back 16 and emits a search signal to a space for searching, receives the search signal, and receives the received signal and the signal used to generate the search signal. Detects a signal that reflects the state of the space, determines the opening and closing of the mirror compared to a preset value, and controls according to the determination result, without taking into account the variation depending on the exposure length The mirror state can be used as a reference timing to accurately expose at each shutter speed.
[0049]
The signal emitting unit 30 can generate a search signal that does not change the space by generating a continuous pulse at a predetermined timing and generating a search signal in response to the pulse. Further, the state detection unit 34 can detect the phase difference as information reflecting the state of the space by detecting the amplitude modulation and comparing the phases of the continuous pulse and the detection signal.
[0050]
The signal emitting unit 30 generates a frequency-modulated signal according to the waveform signal that controls the modulation, and generates a search signal that does not change the space by emitting a search signal according to the frequency-modulated signal. can do. The state detector 34 supplies a frequency-modulated signal to the received signal, demodulates the received signal, and detects the envelope of the demodulated signal, thereby obtaining amplitude for each frequency as information reflecting the state of the space Can do.
[0051]
By making the search signal ultrasonic or infrared, even if it is emitted to the space, it does not change the state of the space and includes information that reflects the state of the space in a non-contact manner before reception. Information can be extracted from
[0052]
Also in the volume change detection device, an exploration signal is generated in the housing, the exploration signal is received, and the state of the space in the housing that is changed by the partition member moving in the housing is detected, so that the movement mechanism of the partition member is used. Thus, the position of the partition member can be known in a non-contact manner without providing communication means for knowing the state (position) of the partition member outside the housing.
[0053]
The volume change detection device can generate a search signal that does not change the space by generating a continuous pulse at a predetermined timing and generating a search signal in response to the pulse. The state detection unit can detect the phase difference as information reflecting the state of the space by detecting the amplitude modulation and comparing the phases of the continuous pulse and the detection signal.
[0054]
As another method, the signal emitting unit can also change the space by generating a frequency-modulated signal according to the waveform signal for controlling the modulation and emitting a search signal according to the frequency-modulated signal. No exploration signal can be generated. The state detector supplies a frequency-modulated signal to the received signal, demodulates the received signal, and detects the envelope of the demodulated signal, thereby obtaining an amplitude for each frequency as information reflecting the state of the space. it can. By making the search signal ultrasonic or infrared, even if it is emitted to the space, it does not change the state of the space and includes information that reflects the state of the space in a non-contact manner before reception. Information can be extracted from Further, by using this result, it is possible to control the controlled device.
[0055]
【The invention's effect】
As described above, according to the mirror open / close detection device of the present invention, the camera back is provided with the open / close detection means, and the movable mechanism is driven in conjunction with the operation of the operation means. Detecting the position state, determining the spatial state from this detection, knowing precisely the operation timing of the mirror, and controlling the functional operation of the camera back according to this timing, the operation and the functional operation of the camera back By suppressing delays and timing variations that occur between the camera and the camera, it is possible to accurately expose and match the shutter operation of the camera body, accurately capture a desired scene, and reduce image quality degradation. .
[0056]
Further, according to the volume change detection device of the present invention, the volume variable mechanism is arranged in the measurement target casing, and the volume in the casing is changed by moving the partition member in conjunction with the operation of the operation means. By detecting this change by the state determination means and determining the state, it is possible to know the state of the housing, and thereby to control the controlled device.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a mirror operation detection circuit disposed in a camera back of a digital camera to which a mirror open / close detection device of the present invention is applied.
2 is a plan view of the overall configuration of the digital camera shown in FIG. 1 as viewed from above.
3 is a diagram for explaining an operation principle of phase fluctuation monitoring in the mirror operation detection circuit of FIG. 1; FIG.
4 is a cross-sectional view in a mirror-down state in which the digital camera of FIG. 2 is cut along a broken line IV-IV.
5 is a cross-sectional view showing a mirror-up state in which the digital camera of FIG. 2 is cut along a broken line IV-IV.
FIG. 6 is a timing chart for explaining the operation timing when the conventional general-purpose camera back is used.
FIG. 7 is a block diagram showing a schematic configuration of a mirror operation detection circuit to which spectrum fluctuation monitoring is applied in the mirror open / close detection device of the present invention.
8 is a diagram for explaining the operation principle of spectrum fluctuation monitoring in the mirror operation detection device of FIG. 7;
[Explanation of symbols]
10 Digital camera
12 Optical system
14 Camera body
16 Camera back
22 Shooting and recording circuit
28 Mirror operation detection circuit
30 Signal output section
32 microphone
34 Status detector
36 Control circuit for mirror
38 Burst pulse generator
40 Ultrasonic transmitter
46 Detection circuit
48 Phase comparison circuit

Claims (7)

An optical system for forming incident light from the object field on the focal plane is disposed in the camera body, and finder means for confirming an optical image from the optical system, and a camera back having an imaging and recording function of the incident light. Provided in the camera body with a movable mechanism attached with a mirror that can be moved in any direction,
Selecting operation timing for a desired scene of the object scene, and operating means for moving the mirror according to the selection;
The camera back is mounted so as to be replaceable, detects the state of the space in the camera body in conjunction with the operation of the operation means, and the position of the mirror based on the detected state of the space And a mirror open / close detector that includes an open / close detector that controls the start of exposure of incident light on the camera back based on the determined result . The apparatus according to claim 1, wherein the open / close detection unit includes a signal emitting unit that emits an exploration signal for examining a state of the space in the space in the camera body;
A signal receiving means for receiving a search signal emitted from the camera body and converting the search signal into an electrical signal;
State detecting means for detecting the state of the space by the electrical signal and the emitted search signal;
Control means for determining a position state of the mirror based on the detected state of the space, and generating a control signal according to the determination result;
The control means controls the start of exposure of the incident light in accordance with the open state of the space indicated by the result of determining the position state of the mirror. 3. The apparatus according to claim 2, wherein the signal emitting means includes pulse generating means for generating continuous pulses at a predetermined timing;
And a means for generating the search signal in response to the supplied continuous pulses and generating the search signal to the camera body. 4. The apparatus according to claim 2, wherein the state detecting means includes first detecting means for detecting amplitude modulation of the received and converted electric signal;
A mirror open / close detection device, comprising: phase comparison means for comparing the phases of a continuous pulse supplied from the signal emitting means at a predetermined timing and the detected signal. 3. The apparatus according to claim 2, wherein the signal emitting means includes waveform generating means for generating a waveform signal for controlling modulation;
Modulation generation means for generating a frequency-modulated signal in accordance with the waveform signal;
And a means for generating the search signal in response to the frequency-modulated signal and generating the search signal to the camera body. 6. The apparatus according to claim 5, wherein the state detecting means receives and converts it into an electrical signal, supplies the frequency-modulated signal to the received signal, and demodulates the received signal;
A mirror open / close detection apparatus comprising: second detection means for detecting an envelope of the demodulated signal.   The apparatus according to any one of claims 2 to 6, wherein the search signal is an ultrasonic wave or an infrared ray.

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