JP4617277B2 - IMAGING DEVICE, ITS CONTROL METHOD, AND COMPUTER PROGRAM - Google Patents

Description

  The present invention relates to an imaging apparatus such as a digital single-lens reflex camera system, a control method thereof, and a computer program, and is particularly suitable for use in an imaging apparatus having a dust removal apparatus that removes dust attached to the surface of an optical member. It is.

  In the interchangeable-lens digital single-lens reflex camera, if there is a foreign object such as dust near the focal plane of the photographing lens, there is a problem that the shadow is reflected on the image sensor. Examples of the dust include dust that enters from the outside when the lens is replaced, and fine wear powder such as resin and metal that are structural members generated by the operation of the shutter and mirror inside the camera.

  Dust generated for such a reason may enter between the cover glass for protecting the image sensor and an optical member such as an infrared cut filter or an optical low-pass filter disposed in front of the cover glass. There is. In this case, the camera had to be disassembled to remove the dust. Therefore, it has been extremely effective to provide a sealed structure so that dust does not enter between the cover glass of the image sensor and the optical member.

  However, if dust adheres to the surface of the optical member opposite to the side facing the image sensor, that is, the surface on the subject side, if the dust is near the focal plane, the dust is reflected in the image sensor as a shadow. The problem still remains.

  In order to solve the above problems, a structure has been proposed in which an optical member that can vibrate is provided on the front surface of the imaging unit, and the optical member is vibrated by a piezoelectric element to remove dust attached to the optical member. (Patent Document 1). With the configuration disclosed in Patent Document 1, dust attached to the outermost surface (for example, the surface of the optical member) of the dustproof structure can be removed without removing the lens and without disassembling the camera.

JP 2002-204379 A

  However, in the conventional dust removing device, the amount of change of the piezoelectric element itself is small. Therefore, it is effective for removing dust attached to the optical member in a dry state, but when the humidity is high, especially when the surface of the optical member is condensed, the dust adheres to the surface of the optical member. Therefore, there is a possibility that dust cannot be removed by vibration.

  In addition, consumer devices such as digital cameras do not have a fixed usage environment. For example, they move to places where the environment changes greatly, such as moving from a ski area where the outside air temperature is low to a warm indoor area. The problem is inevitable.

  Accordingly, an object of the present invention is to enable efficient dust removal before it becomes difficult to remove dust due to condensation.

An imaging apparatus according to the present invention includes an imaging unit that photoelectrically converts an optical image formed by a photographic lens that forms an optical image of a subject, an optical member that is disposed between the photographic lens and the imaging unit, An excitation drive unit that vibrates the optical member to remove dust on the subject-side surface of the optical member, a condensation prediction unit that predicts condensation on the subject-side surface of the optical member, and the condensation prediction unit. It has a feature in that it comprises control means for driving the vibration drive means when condensation is predicted.
An image pickup apparatus control method according to the present invention includes an image pickup unit that photoelectrically converts an optical image formed by a shooting lens that forms an optical image of a subject, and an optical device disposed between the shooting lens and the image pickup unit. An imaging apparatus control method comprising: a member; and an excitation driving unit that vibrates the optical member in order to remove dust on the subject-side surface of the optical member. It is characterized in that it has a control procedure for predicting condensation and driving the vibration drive means when condensation is predicted.
A computer program according to the present invention includes an imaging unit that photoelectrically converts an optical image formed by a photographic lens that forms an optical image of a subject, an optical member that is disposed between the photographic lens and the imaging unit, A computer program for use in an image pickup apparatus including vibration drive means for vibrating the optical member in order to remove dust on the subject-side surface of the optical member, the condensation on the subject-side surface of the optical member And when the dew condensation is predicted, the control processing for driving the vibration drive means is executed by a computer.

  According to the present invention, condensation is predicted and the optical member is vibrated before it is difficult to remove dust attached to the surface of the optical member due to condensation, so that dust can be efficiently removed.

  Further, if condensation is predicted at a predetermined time interval from when the power is turned on (or whether or not condensation is predicted), sensors other than the condensation prediction means are not required. Moreover, if the predetermined time interval can be changed, the time interval can be lengthened as necessary to reduce power consumption.

  In addition, if the color temperature and the outside air temperature under the environment are detected, condensation can be predicted when the environment changes, so that a timer that continuously counts from the time of turning on the power becomes unnecessary.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
1 and 2 are external views of a digital single-lens reflex camera according to the present embodiment. FIG. 1 is a perspective view of the front side of the camera, showing a state in which the taking lens unit is removed. FIG. 2 is a perspective view of the back side of the camera.

  In FIG. 1, reference numeral 1 denotes a camera body, which is provided with a grip portion 1a that protrudes forward so that a user can easily hold the camera stably during shooting. Reference numeral 2 denotes a mount for fixing a detachable photographic lens unit (not shown) to the camera body 1. The mount contact 21 can communicate control signals, status signals, data signals, and the like between the camera body 1 and the photographic lens unit, and has a function of supplying power to the photographic lens unit. Further, the mount contact 21 may be configured not only for electrical communication but also for optical communication and voice communication.

  Reference numeral 4 denotes a lens lock release button that is pushed in when removing the photographing lens unit. Reference numeral 5 denotes a mirror box disposed in the camera body 1, and the photographic light flux that has passed through the photographic lens is guided here. A click return mirror 6 is disposed inside the mirror box 5. As shown in FIG. 3, the quick return mirror 6 guides the imaging light beam in the direction of the imaging element 33 and the position 6 a held at an angle of 45 ° with respect to the imaging optical axis in order to guide the imaging light beam in the direction of the pentaprism 23. Therefore, it is possible to move between the position 6b retracted from the photographing light flux.

  On the upper part of the camera body 1 and on the grip portion 1a side, a release button 7 as a start switch for starting shooting, a main operation dial 8, and a top operation mode setting button 10 for the shooting system are arranged. Some of the operation results of these operation members are displayed on the LCD display panel (external liquid crystal display device) 9. The release button 7 is configured such that SW1 (SW1 (7a) in FIG. 3) is turned on in the first stroke and SW2 (SW2 (7b) in FIG. 3) is turned on in the second stroke. The main operation dial 8 is for setting a shutter speed, a lens aperture value, and the like according to an operation mode at the time of shooting. The top operation mode setting button 10 is used to set whether the continuous shooting or only one frame shooting is performed by pressing the release button 7 once, the self-shooting mode setting, etc. The setting status is displayed on the panel 9.

  A flash unit 11 that pops up with respect to the camera body 1, a shoe groove 12 for attaching a flash, and a flash contact 13 are arranged in the upper center of the camera body 1.

  A shooting mode setting dial 14 is disposed on the upper part of the camera body 1. An external terminal lid 15 that can be opened and closed is provided on the side surface opposite to the grip portion 1a. Inside the external terminal lid 15, the video signal output jack 16 and the USB output are provided as external interfaces. A connector 17 is provided.

  On the front surface of the camera body 1, an ambient light sensor window 22 for measuring a light source in a shooting environment is disposed below the shooting mode setting dial 14. On the grip 1a side, an outside air temperature sensor window 23 for measuring the outside air temperature in the shooting environment is disposed.

  As shown in FIG. 2, a finder eyepiece window 18 is disposed above the back of the camera body 1. On the side of the viewfinder eyepiece window 18, a main switch 43 for turning on / off the power of the camera is disposed. A color liquid crystal monitor 19 capable of displaying an image is disposed near the center. A sub operation dial 20 is arranged beside the color liquid crystal monitor 19. The sub operation dial 20 plays an auxiliary role of the function of the main operation dial 8, and is used, for example, in the AE mode of the camera to set an exposure correction amount with respect to an appropriate exposure value calculated by the automatic exposure device. Alternatively, in the manual mode in which each of the shutter speed and the lens aperture value is set according to the user's will, the shutter speed is set with the main operation dial 8 and the lens aperture value is set with the sub operation dial 20. The sub operation dial 20 is also used for selecting display of a captured image displayed on the color liquid crystal monitor 19.

  FIG. 3 is a block diagram showing the main electrical configuration of the digital single-lens reflex camera according to the first embodiment. In addition, the same code | symbol is attached | subjected to the same component as FIGS. Reference numeral 100 denotes a microcomputer central processing unit (hereinafter referred to as MPU) built in the camera body. The MPU 100 controls the operation of the camera, and executes various processes and instructions for each element.

  The MPU 100 incorporates an EEPROM 100a and can store time information of the time measuring circuit 114 and other information. The MPU 100 includes a mirror drive circuit 101, a focus detection circuit 102, a shutter drive circuit 103, a video signal processing circuit 104, a switch sense circuit 105, a photometry circuit 106, a temperature measurement circuit 113, an absolute humidity measurement circuit 112, and a liquid crystal display drive circuit 107. The battery check circuit 108, the time measurement circuit 114, the power supply circuit 110, and the piezoelectric element drive circuit 111 are connected, and these circuits operate under the control of the MPU 100.

  The MPU 100 communicates with the lens control circuit 81 arranged in the photographing lens unit via the mount contact 21. The mount contact 21 also has a function of transmitting a signal to the MPU 100 when the photographing lens unit is connected. Thereby, the lens control circuit 81 can communicate with the MPU 100 and drive the photographing lens 80 and the diaphragm 84 in the photographing lens unit via the AF driving circuit 82 and the diaphragm driving circuit 83. Become. In the present embodiment, only one photographing lens is shown for convenience, but in actuality, it is composed of a large number of lens groups.

  The AF driving circuit 82 is configured by, for example, a stepping motor, and adjusts the imaging light flux to be focused on the imaging element 33 by changing the focus lens position in the imaging lens 80 under the control of the lens control circuit 81. The aperture driving circuit 83 is constituted by, for example, an auto iris or the like, and the lens control circuit 81 changes the aperture 84 to obtain an optical aperture value.

  The quick return mirror 6 guides the photographic light beam passing through the photographic lens 80 to the pentaprism 23 and transmits a part thereof to the sub mirror 30. The sub mirror 30 guides the photographing light flux that has passed through the quick return mirror 6 to the focus detection sensor unit 31.

  The mirror drive circuit 101 is for driving the quick return mirror 6 to a position 6a where the subject image can be observed by the finder and a position 6b where the subject light image is retracted. At the same time, the sub mirror 30 is driven to a position for guiding the photographing light flux to the focus detection sensor unit 31 and a position for retracting from the photographing light flux. Specifically, the mirror drive circuit 101 is constituted by, for example, a DC motor and a gear train.

  The focus detection sensor unit 31 includes a field lens, a reflection mirror, a secondary imaging lens, a diaphragm, a line sensor composed of a plurality of CCDs, and the like disposed in the vicinity of an imaging surface (not shown). The signal output from the focus detection sensor unit 31 is supplied to the focus detection circuit 102, converted into a subject image signal, and then transmitted to the MPU 100. The MPU 100 performs a focus detection calculation by a phase difference detection method based on the subject image signal. Then, the defocus amount and the defocus direction are obtained, and based on this, the focus lens in the photographing lens 80 is driven to the in-focus position via the lens control circuit 81 and the AF drive circuit 82.

  The pentaprism 23 is an optical member that converts and reflects the photographing light beam reflected by the quick return mirror 6 into an erect image. The user can observe the subject image converted into an erect image by the pentaprism 23 via the eyepiece lens group 18. The pentaprism 23 guides part of the photographing light flux to the photometric sensor 44. The photometric circuit 106 obtains the output of the photometric sensor 44, converts it into a luminance signal for each area on the observation surface, and outputs it to the MPU 100. The MPU 100 calculates an exposure value from the obtained luminance signal.

  The focal plane shutter 32 is a mechanical focal plane shutter, and blocks a photographing light beam when a user observes a subject image with a viewfinder. Further, at the time of imaging, a desired exposure time is obtained by a time difference between a front blade group and a rear blade group (not shown) according to a release signal. The focal plane shutter 32 is controlled by the shutter drive circuit 103 that has received a command from the MPU 100.

  The imaging element 33 is configured by, for example, a CMOS that is an imaging device. There are various types of imaging devices such as a CCD type, a CMOS type, and a CID type, and any type of imaging device may be adopted.

  A clamp / CDS (correlated double sampling) circuit 34 performs basic analog processing before A / D conversion and also changes the clamp level. An AGC (automatic gain adjusting device) 35 performs basic analog processing before A / D conversion, and also changes the AGC basic level. The A / D converter 36 converts the analog output signal of the image sensor 33 into a digital signal.

  The optical filter 51 is configured by laminating and laminating a plurality of birefringent plates and phase plates made of quartz or the like, and further laminating an infrared cut filter. In the present embodiment, the optical filter 51 is described as an integrated configuration of an optical low-pass filter using an infrared cut filter, crystal, or the like. However, the present invention is not limited to this, and a plurality of optical element members are used. The structure which divides | segments into may be sufficient. In that case, an optical member arranged on the outermost surface constituting the sealed structure including the image sensor may be vibrated by a piezoelectric element.

  The piezoelectric element 52 is configured to vibrate integrally with the optical filter 51 by being vibrated by the piezoelectric element driving circuit 111 that receives a command from the MPU 100, and removes dust adhering to the surface of the optical filter 51. It can be done. The imaging unit 50 includes an optical filter 51, a piezoelectric element 52, an imaging element 33, a support member (not shown), and the like.

  A temperature sensor 46 is connected to the temperature measurement circuit 113 and measures the object-side surface temperature of the optical filter 51. In this case, the temperature measurement point of the temperature sensor 46 is preferably set so as to be in direct contact with the subject side surface of the optical filter or in the very vicinity of the subject side surface.

  The absolute humidity measurement circuit 112 is connected to at least a pair of temperature sensor and relative humidity sensor (hereinafter referred to as temperature / humidity sensor) 45 for measuring the temperature and relative humidity in the mirror box 5. In order to measure the amount of water vapor in the atmosphere in the mirror box 5, it is provided toward the inside of the mirror box 5. Details of the calculation of the water vapor amount will be described later.

  The video signal processing circuit 104 performs overall image processing by hardware such as gamma / knee processing, filter processing, and information composition processing for monitor display on the digitized image data. The image data for monitor display from the video signal processing circuit 104 is displayed on the color liquid crystal monitor 19 via the color liquid crystal drive circuit 109. Further, the video signal processing circuit 104 can also store image data in the buffer memory 37 through the memory controller 38 in accordance with an instruction from the MPU 100. Further, the video signal processing circuit 104 has a function of performing image data compression processing such as JPEG. When continuous shooting is performed, such as continuous shooting, image data can be temporarily stored in the buffer memory 37 and unprocessed image data can be sequentially read out via the memory controller 38. Accordingly, the video signal processing circuit 104 can sequentially perform image processing and compression processing regardless of the speed of the image data input from the A / D converter 36.

  The memory controller 38 has a function of storing image data input from the external interface 40 in the memory 39 and a function of outputting image data stored in the memory 39 from the external interface 40. The video signal output jack 16 and the USB output connector 17 in FIG. 1 correspond to the external interface 40. The memory 39 includes a flash memory that can be attached to and detached from the camera body 1.

  The switch sense circuit 105 transmits an input signal to the MPU 100 according to the operation state of each switch. Reference numeral 7a denotes a switch SW1, which is turned on by the first stroke of the release button 7. Reference numeral 7b denotes a switch SW2, which is turned on by the second stroke of the release button 7. When the switch SW2 (7b) is turned on, an instruction to start photographing is transmitted to the MPU 100. The switch operation circuit 105 is connected to the main operation dial 8, the sub operation dial 20, the shooting mode setting dial 14, and the main switch 43.

  The liquid crystal display drive circuit 107 drives the LCD display panel 9 and the in-finder liquid crystal display 41 in accordance with instructions from the MPU 100.

  The battery check circuit 108 performs a battery check for a predetermined time in accordance with a signal from the MPU 100 and transmits the detection output to the MPU 100. The power supply unit 42 supplies necessary power to each element of the camera.

  The time measuring circuit 114 measures the time from when the main switch 43 is turned off to when it is turned on, the elapsed time since it is turned on, the date, and the like, and transmits the measurement result to the MPU 100 according to a command from the MPU 100.

Here, the dew condensation phenomenon will be described with reference to FIG. FIG. 4 is a characteristic diagram showing the relationship of the amount of water vapor (g) in 1 m ³ of air to the air temperature at each humidity. Curve A shows the relationship when the relative humidity is 100% (saturated water vapor), and curves B, C, and D show the relationship when the relative humidity is 90% RH, 60% RH, and 30% RH, respectively. Humidity here refers to relative humidity and is expressed as a percentage of the ratio of the amount of water vapor (g) in 1 m ^{3 of} air to the amount of saturated water vapor. The amount of water vapor (g) in 1 m ^{3 of} air represents absolute humidity.

In the figure, for example, when the air temperature is ta and the humidity is 60% RH, the amount of water represented by the point a on the curve C is present as water vapor in 1 m ^{3 of} air. If the air temperature is lowered from this state, the amount of water vapor in 1 m ^{3 of} air is constant, so that it moves parallel from the point a to the horizontal axis and the relative humidity increases. When the air temperature reaches tb and becomes point b on the curve A, the humidity becomes 100%. Further, assuming that the air temperature has dropped to tc, the point b does not move from the point b in parallel to the horizontal axis and reaches the point d that intersects the line parallel to the vertical axis from tc, but from the point b to the curve A. The point c on the curve A is reached by moving along.

The amount of water in 1 m ³ of air is originally the amount represented by the point d, but at the air temperature tc, the amount of water represented by the point c is present as water vapor in the air and the humidity is 100%. The remaining water amount W from the point c to the point d becomes a liquid and forms dew. This is condensation. This condensation occurs when the state point becomes lower than the air temperature tb at the point b on the curve A having a relative humidity of 100% (saturated water vapor), and the air when the air temperature gradually decreases and condensation starts. The temperature tb is called dew point temperature.

  Therefore, condensation can be predicted in advance by monitoring the surface temperature of the optical filter 51 detected by the temperature measurement circuit 113 and the amount of water vapor in the atmosphere in the mirror box 5 detected by the absolute humidity measurement circuit 112. it can. Thereby, a dust removal apparatus can be efficiently functioned on effective conditions. The amount of water vapor in the atmosphere in the mirror box 5 may be obtained from the air temperature and relative humidity of the atmosphere in the mirror box 5 and a saturated water vapor diagram. In this embodiment, the dust removing device is driven when it is determined that the amount of water vapor in the atmosphere in the mirror box 5 is greater than the amount of water vapor equivalent to 90% RH at the surface temperature of the optical filter 51.

  With reference to FIG.5 and FIG.6, the dew condensation prediction for driving the specific dust removal apparatus in this embodiment is demonstrated. FIG. 5 is a diagram for explaining dew condensation prediction when the camera moves from a low temperature environment to a high temperature environment. When the temperature tM in the mirror box 5 in the low temperature environment of the camera is ta and the relative humidity hM is 60% RH (state point a), the result of moving the camera in the high temperature environment is the result of the mirror box being moved. It is assumed that the temperature in 5 has increased from ta to tb.

  State points such as when the camera is highly sealed (the amount of water vapor in the camera is not easily affected by the ambient atmosphere), or when the relative humidity of the atmosphere in a high temperature environment is low (the amount of water vapor is small) Suppose a moves to state point b. In this case, the surface temperature tL of the optical filter 51 is ta, and the air temperature of the atmosphere in the mirror box 5 is rapidly cooled from tb to ta on this surface. Accordingly, the surface of the optical filter 51 moves from the state point b to the state point c corresponding to the temperature ta in parallel with the horizontal axis. However, at a state point c that does not exceed a line parallel to the horizontal axis at a relative humidity of 90% at ta in the figure, it is not necessary to determine that no condensation occurs and drive the dust removing device.

  On the other hand, if the camera's hermeticity is low (the amount of water vapor in the camera is easily affected by the ambient atmosphere), and the relative humidity of the atmosphere in a high temperature environment is high (the amount of water vapor is large). In some cases, it is assumed that the state point a moves to the state point d. In this case, the surface temperature tL of the optical filter 51 is ta, and the air temperature of the atmosphere in the mirror box 5 is rapidly cooled from tb to ta on this surface. Therefore, the surface of the optical filter 51 moves from the state point d to the state point e corresponding to the temperature ta in parallel with the horizontal axis. In this case, since the state point e reaches a line parallel to the horizontal axis at a relative humidity of 90% at ta in the figure, it is determined that condensation occurs and the dust removing device is driven.

  FIG. 6 is a diagram for explaining dew condensation prediction when the camera moves from a high temperature environment to a low temperature environment. When the temperature tM in the mirror box 5 under the high temperature environment of the camera is tc and the relative humidity hM is 60% RH (state point f), as a result of moving the camera under the low temperature environment, the mirror box 5 It is assumed that the temperature inside falls from tc to td.

  If the camera has a high airtightness (the amount of water vapor in the camera is not easily affected by the ambient atmosphere), or the camera has a low airtightness, but the ambient humidity in a low temperature environment is high (high temperature It is assumed that the air temperature of the atmosphere in the mirror box 5 drops from tc to td and moves from the state point f to the state point g corresponding to the temperature td. In this case, if it exceeds a line parallel to the horizontal axis at a relative humidity of 90% at td in the figure, it is determined that condensation occurs and the dust removing device is driven.

  On the other hand, if the sealing performance of the camera is low (the amount of water vapor in the camera is easily affected by the ambient atmosphere), the relative humidity of the atmosphere in a low temperature environment is low (the same as in a high temperature environment). It is assumed that the air temperature of the atmosphere in the mirror box 5 drops from tc to td and moves from the state point f to the state point h corresponding to the temperature td. In this case, since it does not exceed a line parallel to the horizontal axis at 90% relative humidity at td in the figure, it is not necessary to determine that there is no condensation and to drive the dust removing device.

  Hereinafter, the imaging routine will be described first with reference to the flowchart shown in FIG. This process is performed by the MPU 100 executing an imaging program stored in a non-volatile memory (not shown).

  When the imaging routine is executed, in step S301, the aperture 84 is driven to the aperture based on the photometric value via the lens control circuit 81 and the aperture drive circuit 83. In step S302, the quick return mirror 6 and the sub mirror 30 are driven via the mirror drive circuit 101, and the quick return mirror 6 is retracted to the position 6b outside the photographing optical path.

  In step 303, charge accumulation for image formation in the image sensor 33 is started. In step S304, a front blade group (not shown) of the shutter 32 is driven via the shutter drive circuit 103, and in step S305, exposure is performed.

  In step S306, a rear blade group (not shown) of the shutter 32 is driven via the shutter drive circuit 103. In step S307, the exposure is terminated and the accumulation of charges for image formation is terminated.

  In step S308, the image signal is read from the image sensor 33 and temporarily stored in an internal memory (not shown) built in the image processing circuit 104 shown in FIG. After all the image signals have been read, the process proceeds to step S309.

  In step S309, the quick return mirror 6 is driven to a position 6a for guiding the photographing light flux to the finder optical system via the mirror driving circuit 101. In step S310, the front and rear curtains are driven to return to the original standby position (charged state) via the shutter drive circuit 103.

  In step S311, the diaphragm 84 in the state that has been squeezed in step S301 is driven to open through the lens control circuit 81 and the diaphragm drive circuit 83, and the series of imaging operations is completed.

  FIG. 8 is a flowchart illustrating a processing operation for driving the dust removing device by predicting condensation in the digital single-lens reflex camera according to the first embodiment. This process is performed by executing a program stored in the nonvolatile memory in the MPU 100.

In step S201, it is determined whether or not the main SW 43 is turned on, and the state of the main SW 43 is continuously checked until it is turned on. When the main SW 43 is turned on, the camera is activated, and the process proceeds to step S202. In step S202, in order to calculate the absolute humidity in the mirror box 5 by the absolute humidity measuring circuit 112, the temperature and humidity sensor 45 measures the temperature tM ₁ and the relative humidity hM ₁ in the mirror box 5. Specifically, the absolute humidity measurement circuit 112 is configured to calculate the temperature tM ₁ and the relative humidity hM ₁ obtained by the temperature / humidity sensor 45, the temperature stored in the memory provided in the absolute humidity measurement circuit, and the saturated water vapor amount. Absolute humidity is calculated from a table representing the relationship.

In step S203, the time measuring circuit 114 starts the timer T _i is the measurement interval of the absolute humidity measurement circuit 112. In step S204, it is determined whether or not the timer T _i started by the time measuring circuit 114 in step S203 has passed a predetermined time. If the predetermined time has elapsed, the process proceeds to step S210, and if the predetermined time has not elapsed, the process proceeds to step S205. The predetermined time here is preferably set, for example, between 1 minute and 15 minutes, assuming a time to move from one continuous photographing operation to the next photographing operation. Needless to say, it may be changed at any time depending on the absolute humidity, temperature, etc. in the mirror box 5.

  In step S205, it is determined whether SW1 (7a), which is turned on by half-pressing the release button 7, is turned on. If SW1 (7a) is not turned on, the process returns to step S204. If SW1 (7a) is turned on, the camera is ready for shooting, and the process proceeds to step S206.

  In step S <b> 206, photometry is performed by the photometry circuit 106 using the photometry sensor 44, and distance measurement is performed by the focus detection circuit 102 using the focus detection sensor unit 31. Then, the photographing lens 80 is driven to the focal position based on the information of the distance measurement result via the lens control circuit 81 and the AF driving circuit 82.

  In step S207, it is determined whether SW2 (7b), which is turned on when the release button 7 is fully pressed, is turned on. If SW2 (7b) is turned on, the camera proceeds to step S208, which is an imaging routine. If SW2 (7b) is not turned on, the process proceeds to step S209. Note that the imaging routine in step S208 is as described with reference to FIG. 7, and the description thereof is omitted here.

In step S209, it is determined whether SW1 (7a) is in an ON state. If the ON state of SW1 (7a) seems to continue, the confirmation is continued until SW2 (7b) is turned ON in step S207, and if SW1 (7a) is OFF, the process returns to step S204. to confirm the lapse of a predetermined time of the timer T _i.

On the other hand, in step S210, the temperature tM _n and the relative humidity hM _n in the mirror box 5 are measured in response to the elapse of the timer T _i in step S204. Then, similar to step S202, the current absolute humidity is calculated.

In step S211, the absolute humidity in the mirror box 5 measured this time is compared with the absolute humidity measured last time. When the timer T _i ends for the first time after the main SW 43 is turned on in step S201, the absolute humidity calculated by tM ₁ and hM ₁ and the absolute humidity calculated by tM _n and hM _n (in this case, n = 2) are obtained. From now on, the absolute humidity calculated by tM _n and hM _n and the absolute humidity calculated by tM _n−1 and hM _n−1 are compared each time the timer T _i elapses until the main SW 43 is turned off.

As a result of the comparison, it is determined whether or not the change in absolute humidity exceeds a threshold value. If there is a change exceeding the threshold, the process proceeds to step S212, and if there is no change exceeding the threshold, the process returns to step S203. If this threshold value is decreased, prediction judgment is frequently executed, and power consumption increases. However, if this threshold value is increased, the prediction timing becomes difficult. Therefore, in terms of change in absolute humidity, 1 g / m ^{3 to} 5 g / m. ^It is desirable to set between ³ . Needless to say, the initial absolute humidity calculated by tM ₁ and hM ₁ may be changed as needed.

In step S <b> 212, the surface temperature tL _m of the optical filter 51 is measured via the temperature measurement circuit 113 in response to the change in the atmosphere in the mirror box 5. In step S213, the dew condensation prediction described in FIGS. 5 and 6 is performed using the absolute humidity in the mirror box 5 measured in step S210 and the surface temperature tL _m of the optical filter 51 measured in step S212. To do.

If it is predicted that condensation will occur, the process proceeds to step S215. If it is predicted that condensation will not occur, the process proceeds to step S214. In step S214, it is predicted that no condensation occurs. However, since a change in absolute humidity is observed, the time measurement circuit 114 changes the timer _Ti to a shorter time because the possibility of condensation is high in the future. Specifically, a new timer T _i (T _i = T _i −T _ia ) obtained by subtracting T _ia from T _i is set, and the process returns to step S203.

  In step S215, the piezoelectric element 52 attached to the optical filter 51 is driven via the piezoelectric element driving circuit 111 to cause vibration in the optical filter 51 and remove dust adhering to the surface of the optical filter 51. To do.

In step S216, since it is after the removal drive by dust removing device, to change the timer T _i to a longer time. Specifically, setting the T _i to T _ia newly obtained by adding timer _{T i (T i = T i} + T ia). In step S217, it is determined whether or not the main SW 43 is turned off. Main SW43 is returned to step S203 if left in the ON state, to start the newly set timer T _i. When the main SW 43 is turned off, the camera is turned off and the process is terminated.

  As described above, according to the digital single lens reflex camera including the dust removing device of the first embodiment, the image sensor 33 that photoelectrically converts the subject image, and the image sensor 33 and the photographing lens 80 are disposed. Optical member (optical filter 51), vibration means (piezoelectric element 52) for vibrating optical filter 51, and temperature measuring means (temperature sensor 46 and temperature measuring circuit 113) for measuring the subject-side surface temperature of optical filter 51 And a water vapor amount measuring means (temperature / humidity sensor 45 and absolute humidity measuring circuit 112) for measuring the absolute humidity (temperature and relative humidity) in the mirror box 5, and measuring the absolute humidity every predetermined time, and an optical filter Since the dust removing device is driven when the surface of the optical filter 51 reaches 90% of the saturated water vapor amount as compared with the surface temperature of the subject 51, the dust is removed due to condensation. It can be efficiently performed dust removal before it becomes difficult to take.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 9 is a block diagram showing the main electrical configuration of the digital single-lens reflex camera according to the second embodiment. In addition, the same code | symbol is attached | subjected to the component similar to the said 1st Embodiment, and the detailed description is abbreviate | omitted.

  In FIG. 9, reference numeral 120 denotes an ambient light measurement circuit, which obtains the output of the ambient light sensor 47, detects the light source state in the environment where the current camera is placed, and outputs it to the MPU 100. The MPU 100 calculates the color temperature under the shooting environment based on the signal obtained from the ambient light measurement circuit 120, and uses this as information when determining the white balance.

  FIG. 10 is a flowchart for explaining a processing operation for driving the dust removing device by predicting condensation in the digital single-lens reflex camera according to the second embodiment. This process is performed by executing a program stored in the nonvolatile memory in the MPU 100.

  In step S401, it is determined whether or not the main SW 43 is turned on, and the state of the main SW 43 is continuously checked until it is turned on. When the main SW 43 is turned on, the camera is activated, and the process proceeds to step S402. In step S402, the ambient light sensor 47 is used by the ambient light measurement circuit 120 to measure the light source in the environment where the camera is present to obtain color temperature information.

In step S403, in order to calculate the absolute humidity in the mirror box 5 by the absolute humidity measurement circuit 112, the temperature tM ₁ and the relative humidity hM ₁ in the mirror box 5 are measured by the temperature / humidity sensor 45. Specifically, the absolute humidity measurement circuit 112 is configured to calculate the temperature tM ₁ and the relative humidity hM ₁ obtained by the temperature / humidity sensor 45, the temperature stored in the memory provided in the absolute humidity measurement circuit, and the saturated water vapor amount. Absolute humidity is calculated from a table representing the relationship.

  In step S404, it is determined whether or not SW1 (7a), which is turned on when the release button 7 is pressed halfway, is turned on. When SW1 (7a) is not turned on, the state of SW1 (7a) is continuously checked until it is turned on. When SW1 (7a) is turned on, the camera is in a shooting preparation state, and the process proceeds to step S405.

  In step S405, photometry is performed by the photometry circuit 106 using the photometry sensor 44, and distance measurement is performed by the focus detection circuit 102 using the focus detection sensor unit 31. Then, the photographing lens 80 is driven to the focal position based on the information of the distance measurement result via the lens control circuit 81 and the AF driving circuit 82.

  In step S406, the ambient light measurement circuit 120 uses the ambient light sensor 47 to measure the light source in the environment where the camera exists, and obtains color temperature information. In step S407, the color temperature measured this time is compared with the color temperature measured last time. As a result, if the change in color temperature exceeds the threshold, it is determined that the environment where the camera is placed has changed, and the process proceeds to step S414. If the change in color temperature does not exceed the threshold, the process proceeds to step S409. This threshold value is preferably set in the range of, for example, 200K or more and 1000K or less in consideration of the movement from the outdoors to the room and considering that it is about 5200K in fine weather and about 4200K under fluorescent lamps.

  In step S409, it is determined whether or not SW2 (7b), which is turned on when the release button 7 is fully pressed, is turned on. If SW2 (7b) is turned on, the camera proceeds to step S410, which is an imaging routine. If SW2 (7b) is not turned on, the process proceeds to step S417. Note that the imaging routine of step S410 is as described with reference to FIG. 7, and the description thereof is omitted here. In step S411, it is determined whether SW2 (7b) is ON. If SW2 (7b) is turned on, the camera proceeds to step S410, which is an imaging routine, and if SW2 (7b) is turned off, the process proceeds to step S412.

  In step S412, it is determined whether SW1 (7a) is turned off. If the ON state seems to continue, the confirmation is continued until SW2 (7b) is turned ON or SW1 (7a) is turned OFF in step S409. If SW1 (7a) is turned OFF, the step is continued. The process proceeds to S419.

In step S414, in order to measure the absolute humidity of the atmosphere in the mirror box 5, the temperature tM _n and the relative humidity hM _n in the mirror box 5 are measured. Further, the surface temperature tL _m of the optical filter 51 is measured via the temperature measurement circuit 113.

In step S415, carried out a surface temperature tL _m of the optical filter 51 measured this time, by using the absolute humidity in the mirror box 5, a condensation prediction explained in FIGS.

  If it is predicted that condensation will occur, the process proceeds to step S416. If it is predicted that condensation will not occur, the process proceeds to step S417.

  In step S416, the piezoelectric element 52 attached to the optical filter 51 is driven via the piezoelectric element driving circuit 111 to cause vibration in the optical filter 51, and dust or the like adhering to the surface of the optical filter 51 is removed. Remove.

  In step S417, it is determined whether SW1 (7a) is turned off. If the ON state seems to continue, the confirmation is continued until SW2 (7b) is turned ON or SW1 (7a) is turned OFF in step S418. If SW1 (7a) is turned OFF, step S419 is continued. Proceed to

  In step S418, it is determined whether SW2 (7b) is turned on. If SW2 (7b) is on, the camera proceeds to step S410, which is an imaging routine. If SW2 (7b) is not on, the process proceeds to step S412.

  In step S419, it is determined whether or not the main SW 43 is turned off. If the main SW 43 remains on, the process returns to step S404. If the main SW 43 is off, the camera is turned off and the process is terminated.

  As described above, according to the digital single lens reflex camera including the dust removing device of the second embodiment, the image sensor 33 that photoelectrically converts the subject image, and the image sensor 33 and the photographing lens 80 are disposed. Optical member (optical filter 51), vibration means (piezoelectric element 52) for vibrating optical filter 51, and temperature measuring means (temperature sensor 46 and temperature measuring circuit 113) for measuring the subject-side surface temperature of optical filter 51 And a water vapor amount measuring means (temperature / humidity sensor 45 and absolute humidity measuring circuit 112) for measuring the absolute humidity (temperature and relative humidity) in the mirror box 5, and ambient light for measuring the color temperature in the environment where the camera exists. Measurement means (environmental light sensor 47 and ambient light measurement circuit 120) are provided, and condensation prediction is performed when the color temperature changes beyond a predetermined threshold. This gives the timing to measure absolute humidity in the normal white balance setting sequence, eliminates the need to set a continuous timer from when the power is turned on, and effectively removes dust before it becomes difficult to remove dust. Dust removal can be performed.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 11 is a block diagram illustrating a main electrical configuration of a digital single-lens reflex camera according to the third embodiment. In addition, the same code | symbol is attached | subjected to the component similar to the said 1st Embodiment, and the detailed description is abbreviate | omitted.

  In FIG. 11, reference numeral 130 denotes an outside air temperature measurement circuit, which obtains the output of the outside air temperature sensor 48, detects the outside air temperature under the environment where the current camera is placed, and outputs it to the MPU 100.

  FIG. 12 is a flowchart for explaining a processing operation for driving the dust removing device by predicting condensation in the digital single-lens reflex camera according to the third embodiment. This process is performed by executing a program stored in the nonvolatile memory in the MPU 100.

  In step S501, it is determined whether or not the main SW 43 is turned on, and the state of the main SW 43 is continuously checked until it is turned on. When the main SW 43 is turned on, the camera is activated, and the process proceeds to step S502. In step S502, the outside air temperature sensor 48 measures the outside air temperature in the environment where the camera exists by the outside air temperature measuring circuit 130.

At step S503, the surface temperature tL ₁ of the optical filter 51, in order to calculate the absolute humidity in the mirror box 5, the temperature and humidity sensor 45 measures the temperature tM ₁ and relative humidity hM ₁ in the mirror box 5. Specifically, the absolute humidity measurement circuit 112 is configured to calculate the temperature tM ₁ and the relative humidity hM ₁ obtained by the temperature / humidity sensor 45, the temperature stored in the memory provided in the absolute humidity measurement circuit, and the saturated water vapor amount. Absolute humidity is calculated from a table representing the relationship.

  In step S504, it is determined whether or not SW1 (7a), which is turned on when the release button 7 is pressed halfway, is turned on. When SW1 (7a) is not turned on, the state of SW1 (7a) is continuously checked until it is turned on. If SW1 (7a) is turned on, the camera is ready for shooting, and the process proceeds to step S505.

  In step S505, photometry is performed by the photometry circuit 106 using the photometry sensor 44, and distance measurement is performed by the focus detection circuit 102 using the focus detection sensor unit 31. Then, the photographing lens 80 is driven to the focal position based on the information of the distance measurement result via the lens control circuit 81 and the AF driving circuit 82.

In step S <b> 506, the outside temperature sensor 48 measures the outside temperature in the environment where the camera exists using the outside temperature measuring circuit 130. In step S507, the outside temperature measured this time is compared with the outside temperature measured last time. As a result, if the change in the outside air temperature exceeds the threshold, it is determined that the environment where the camera is placed has changed, and the process proceeds to step S514. If the change in the outside air temperature does not exceed the threshold, the process proceeds to step S509. This threshold, taking into account the margin of the temperature variation from the saturated water vapor content obtained from the surface temperature tL ₁ absolute measured humidity and the optical filter 51 in step S503 until the relative humidity of 90% when the amount of steam is constant It is desirable to set. For example, ta and tb in the case of FIG. 5, half of the temperature difference between tc and td in the case of FIG.

  In step S509, it is determined whether SW2 (7b), which is turned on when the release button 7 is fully pressed, is turned on. If SW2 (7b) is turned on, the camera proceeds to step S510, which is an imaging routine. If SW2 (7b) is not turned on, the process proceeds to step S517. Note that the imaging routine in step S510 is as described with reference to FIG. 7, and the description thereof is omitted here. In step S511, it is determined whether SW2 (7b) is ON. If SW2 (7b) is turned on, the camera proceeds to step S510, which is an imaging routine. If SW2 (7b) is turned off, the process proceeds to step S512.

  In step S512, it is determined whether SW1 (7a) is turned off. If the ON state seems to continue, the confirmation is continued until SW2 (7b) is turned ON or SW1 (7a) is turned OFF in step S509. If SW1 (7a) is turned OFF, the step is continued. The process proceeds to S519.

In step S514, in order to measure the absolute humidity of the atmosphere in the mirror box 5, the temperature tM _n and the relative humidity hM _n in the mirror box 5 are measured. Further, the surface temperature tL _m of the optical filter 51 is measured via the temperature measurement circuit 113.

In step S515, the condensation prediction described with reference to FIGS. 5 and 6 is performed using the surface temperature tL _m of the optical filter 51 measured this time and the absolute humidity in the mirror box 5.

  If it is predicted that condensation will occur, the process proceeds to step S516. If it is predicted that condensation will not occur, the process proceeds to step S415.

  In step S516, the piezoelectric element 52 attached to the optical filter 51 is driven via the piezoelectric element driving circuit 111 to cause vibration in the optical filter 51, so that dust or the like adhering to the surface of the optical filter 51 is removed. Remove.

  In step S517, it is determined whether SW1 (7a) is turned off. If the ON state seems to continue, the confirmation is continued until SW2 (7b) is turned ON or SW1 (7a) is turned OFF in step S518. If SW1 (7a) is turned OFF, step S519 is continued. Proceed to

  In step S518, it is determined whether SW2 (7b) is turned on. If SW2 (7b) is turned on, the camera proceeds to step S510, which is an imaging routine. If SW2 (7b) is not turned on, the process proceeds to step S512.

  In step S519, it is determined whether or not the main SW 43 is turned off. If the main SW 43 remains on, the process returns to step S504. If the main SW 43 is off, the camera is turned off and the process is terminated.

  As described above, according to the digital single-lens reflex camera including the dust removing device of the third embodiment, the image sensor 33 that photoelectrically converts the subject image, and the image sensor 33 and the photographing lens 80 are disposed. Optical member (optical filter 51), vibration means (piezoelectric element 52) for vibrating optical filter 51, and temperature measuring means (temperature sensor 46 and temperature measuring circuit 113) for measuring the subject-side surface temperature of optical filter 51 And a water vapor amount measuring means (temperature / humidity sensor 45 and absolute humidity measuring circuit 112) for measuring the absolute humidity (temperature and relative humidity) in the mirror box 5, and an outside air temperature for measuring the outside air temperature in the environment where the camera exists. Measurement means (outside temperature sensor 48 and outside temperature measuring circuit 130) are provided, and condensation prediction is performed when the outside temperature changes beyond a predetermined threshold. It was. As a result, it is possible to obtain timing to measure absolute humidity by directly detecting changes in the camera environment, and it is not necessary to set a continuous timer from the time of power-on, and it is efficient before dust is difficult to remove due to condensation. Dust removal can be performed.

  It goes without saying that the present invention is not limited to the above-described embodiment, and may be implemented by combining a plurality of the above-described embodiments, for example. Also, a plurality of temperature measuring means for measuring the surface temperature of the optical member may be arranged, and the average of each position may be tL. Needless to say, the timer time and each threshold value are not limited to those in the embodiment, and may be set according to the sealing degree of the imaging device, the appearance material, and the like.

  An object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. Needless to say, this can also be achieved by reading and executing the program code stored in.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention.

  As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (basic system or operating system) running on the computer based on the instruction of the program code. Needless to say, a case where the functions of the above-described embodiment are realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

It is a perspective view of the front side of the digital single-lens reflex camera concerning this embodiment. It is a perspective view of the back side of the digital single-lens reflex camera concerning this embodiment. It is a block diagram which shows the main electrical structures of the digital single-lens reflex camera which concerns on 1st Embodiment. It is a characteristic view showing the relationship of the amount of water vapor (g) in 1 m ³ of air to the air temperature at each humidity. It is a figure for demonstrating dew condensation prediction when a camera moves to the high temperature environment from the low temperature environment. It is a figure for demonstrating dew condensation prediction when a camera moves to the low temperature environment from the high temperature environment. It is a flowchart explaining an imaging routine. It is a flowchart explaining the processing operation | movement for predicting the dew condensation in the digital single-lens reflex camera which concerns on 1st Embodiment, and driving a dust removal apparatus. It is a block diagram which shows the main electrical structures of the digital single-lens reflex camera which concerns on 2nd Embodiment. It is a flowchart explaining the processing operation | movement for estimating the dew condensation in the digital single-lens reflex camera which concerns on 2nd Embodiment, and driving a dust removal apparatus. It is a block diagram which shows the main electrical structures of the digital single-lens reflex camera which concerns on 3rd Embodiment. It is a flowchart explaining the processing operation | movement for estimating the dew condensation in the digital single-lens reflex camera which concerns on 3rd Embodiment, and driving a dust removal apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera body 2 Mount 6 Quick return mirror 19 Color liquid crystal monitor 33 Image pick-up element 46 Temperature sensor 47 Ambient light sensor 48 Outside temperature sensor 51 Optical filter 52 Piezoelectric element 100 MPU
111 Piezoelectric element drive circuit 112 Absolute humidity measurement circuit 113 Temperature measurement circuit 120 Ambient light measurement circuit 130 Outside air temperature measurement circuit

Claims (10)

An imaging means for photoelectrically converting an optical image formed by a photographic lens that forms an optical image of a subject;
An optical member disposed between the photographing lens and the imaging means;
Vibration drive means for vibrating the optical member to remove dust on the object-side surface of the optical member;
Condensation prediction means for predicting condensation on the subject side surface of the optical member;
An imaging apparatus comprising: control means for driving the vibration drive means when condensation is predicted by the condensation prediction means. Surface temperature measuring means for measuring a subject-side surface temperature of the optical member;
Water vapor amount measuring means for measuring the amount of water vapor in the atmosphere between the photographic lens and the optical member,
The dew condensation predicting means is based on a saturated water vapor curve representing a change in the saturated water vapor amount in the air with respect to a change in temperature, using the surface temperature measured by the surface temperature measuring means and the water vapor amount measured by the water vapor amount measuring means. The imaging apparatus according to claim 1, wherein condensation on a surface on the subject side of the optical member is predicted.   The water vapor amount measuring means includes a spatial temperature measuring means for measuring the temperature of the atmosphere between the photographing lens and the optical member, and a relative for measuring the relative humidity of the atmosphere between the photographing lens and the optical member. The imaging apparatus according to claim 2, comprising a humidity measuring unit.   4. The method according to claim 1, wherein whether the condensation prediction by the condensation prediction unit is predicted or the prediction of condensation by the condensation prediction unit is determined at a predetermined time interval from when the power is turned on. The imaging apparatus of Claim 1.   The imaging apparatus according to claim 4, wherein the predetermined time interval is changed according to a result of the dew condensation prediction unit. Color temperature measurement means for measuring the color temperature under the environment
The dew condensation prediction by the dew condensation prediction unit is performed when a change in the color temperature measured by the color temperature measurement unit exceeds a predetermined value. The imaging device described in 1.   The imaging apparatus according to claim 6, wherein the predetermined value is a color temperature set in a range of 200 K (Kelvin) to 1000 K (Kelvin). An outside temperature measuring means for measuring the outside temperature in the environment is provided.
The dew condensation prediction by the dew condensation prediction unit is performed when a change in the outside air temperature measured by the outside air temperature measurement unit exceeds a predetermined value. The imaging device described in 1. An imaging means for photoelectrically converting an optical image formed by a photographic lens that forms an optical image of a subject;
An optical member disposed between the photographing lens and the imaging means;
A control method for an imaging apparatus, comprising: an excitation drive unit that vibrates the optical member in order to remove dust on the subject side surface of the optical member,
A control method for an imaging apparatus, comprising: a control procedure for predicting dew condensation on the subject side surface of the optical member, and driving the excitation drive means when dew condensation is predicted. An imaging means for photoelectrically converting an optical image formed by a photographic lens that forms an optical image of a subject;
An optical member disposed between the photographing lens and the imaging means;
A computer program for use in an imaging apparatus comprising vibration drive means for vibrating the optical member in order to remove dust on the subject-side surface of the optical member,
A computer program that predicts condensation on the subject-side surface of the optical member and causes the computer to execute control processing for driving the vibration drive means when condensation is predicted.

Images