JP2021076692A - Imaging apparatus - Google Patents

Abstract

To provide an imaging apparatus in a configuration in which a surface of an image pick-up device hardly gets dirty even when an environment around the imaging apparatus is changed from a low-temperature environment to a high-temperature or high-humidity environment.SOLUTION: An imaging apparatus comprises: an image pick-up device (3); a mechanical shutter mechanism (9) that is closer to a subject than the image pick-up device (3); and at least two temperature detection means (11A, 11B). In accordance with a first temperature detection result (11a) obtained from the first temperature detection means (11A) and a second temperature detection result (11b) obtained from the second temperature detection means (11B), the imaging apparatus switches between an open state where a surface of the image pick-up device (3) is not shielded by the mechanical shutter mechanism (9) and a closed state where the surface of the image pick-up device (3) is shielded by the mechanical shutter mechanism (9).SELECTED DRAWING: Figure 1

Description

The present invention relates to an imaging device including a mechanical shutter mechanism.

Conventionally, in a single-lens reflex type digital still camera, the subject can be confirmed in real time by forming an image of the light reflected by the mirror arranged in the imaging optical path on the focusing screen. Then, when the user operates the shutter button, the mirror in the image sensor is lifted and the shutter curtain arranged in front of the image sensor is opened according to the shutter speed, so that the image sensor is exposed and a still image is displayed. To be acquired.

On the other hand, many so-called mirrorless interchangeable-lens cameras, which can be reduced in size and weight by omitting a part of a plurality of optical members such as the mirror and the focusing screen, have become widespread.

Further, an imaging device having a function of preventing a failure occurring in the imaging device due to a change in the surrounding environment by switching the open / closed state of the shutter curtain has been developed. Patent Document 1 discloses a means for preventing deterioration of the shutter curtain by opening the shutter curtain according to the intensity of the incident light incident through the lens.

Japanese Unexamined Patent Publication No. 2012-220545

Generally, when the ambient environment of the image sensor changes from a low temperature environment to a high temperature or high humidity environment, or when the surrounding warm or high humidity atmosphere comes into contact with the surface of the low temperature image sensor, dew condensation occurs on the surface of the image sensor. It ends up. Then, minute dust floating in the atmosphere in front of the image sensor and minute dust existing on the surface of the image sensor enter the generated dew condensation particles. As a result, the fine dust aggregates with the volatilization of the dew condensation particles, and the surface of the image sensor is soiled.

However, in the prior art disclosed in Patent Document 1, the opening and closing of the shutter cannot be controlled by a change in the temperature or humidity around the image pickup apparatus.

Therefore, an object of the present invention is to provide an image pickup device having a configuration in which the surface of the image pickup device is not easily soiled even when the ambient environment of the image pickup device changes from a low temperature environment to a high temperature or high humidity environment.

In order to achieve the above object, the imaging device according to the present invention is
It is provided with an image sensor, a mechanical shutter mechanism on the subject side of the image sensor, and at least two temperature detecting means.
The surface of the image sensor is shielded by the mechanical shutter mechanism by the first temperature detection result obtained from the first temperature detecting means and the second temperature detection result obtained from the second temperature detecting means. It is characterized in that it switches between a non-open state and a closed state in which the surface of the image sensor is shielded by the mechanical shutter mechanism.

According to the present invention, it is possible to provide an image pickup apparatus capable of preventing the surface of the image pickup device from being soiled due to dew condensation.

Flow chart of dew condensation prevention operation in the first embodiment Sectional drawing which shows the structure of the digital single-lens camera (shutter open state) in 1st Embodiment Sectional drawing which shows the structure of the digital single-lens camera (shutter closed state) in 1st Embodiment Block diagram showing the electrical configuration of the digital single-lens reflex camera of the first embodiment Flow chart of dew condensation prevention operation in the second embodiment

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

FIG. 2 is a cross-sectional view showing a schematic configuration of an image pickup apparatus according to an embodiment of the present invention.

As shown in FIG. 2, a photographing lens unit 2 having a photographing optical system is detachably attached to the imaging device 100 via a mount 1. The photographing lens unit 2 having the photographing optical system is not replaceable and may be integrally fixed to the imaging device 100.

The image pickup apparatus 100 is provided with a shutter 9 and an image pickup device 3. The exposure of the light beam is controlled by slitting the front curtain 9a and the rear curtain 9b installed on the shutter 9 of the photographed light collected by the photographing lens unit 2. After that, the luminous flux that has passed through the shutter is guided to the image sensor 3. In this embodiment, a so-called normally open type imaging device in which the shutter 9 stands by in an open state when the power is turned off will be described. A field image (optical image) that has passed through the photographing optical system is imaged on the image sensor 3, and the image sensor 3 outputs an electric signal (analog signal or image signal) corresponding to the optical image by photoelectric conversion. .. As the image sensor 3, for example, a CMOS (Complementary MOS) sensor is used. Instead of the CMOS sensor, another imaging device such as a CCD (Charge Couple Device) sensor may be used.

The image pickup apparatus 100 is provided with an eyepiece portion used by the photographer to take a picture while observing the subject. In this embodiment, an electronic view composed of a viewfinder display unit 5 and an eyepiece lens 6 is provided. It is a finder 10. In the viewfinder display unit 5, the photographed field image guided to the image pickup element 3 by the photographing lens unit 2 is subjected to photoelectric conversion processing and displayed. The displayed photographed field can be easily viewed by the photographer through the eyepiece 6. An eyepiece frame 7 is arranged behind the electronic viewfinder 10. When the photographer looks into the electronic viewfinder 10 within a certain distance from the eyepiece frame 7, the viewfinder display 5 can be visually recognized without vignetting, and external light is incident on the eyepiece frame 7 to provide a field of view. It is the optimum size to prevent obstruction.

Behind the eyepiece frame, an eye position detecting means 8 for detecting the position of the photographer's eye is arranged. In this embodiment, the eye position detecting means 8 is arranged on the photographer side of the eyepiece frame 7 so as not to interfere with the eyepiece frame 7. However, this does not apply to the location where the eye position detecting means 8 is arranged. As a method for detecting the position of the eye by the eye position detecting means 8, a method using a known technique such as an image recognition function, an autofocus function of a camera, or reflection of infrared rays is used. The TFT monitor 4 arranged under the eyepiece frame is an external display device using a TFT color liquid crystal display or the like, and when confirming a preview image immediately after shooting or an image already recorded in a recording unit in the image pickup device. Used for.

The exterior 12 is the exterior of the housing that includes the image sensor 3 and the shutter 9.

The two environmental measuring means 11A and 11B are environmental measuring means capable of measuring one or both of temperature and humidity. In this embodiment, of the two environment measuring means 11A and 11B, the environment measuring means capable of measuring a value closer to the surrounding environment of the imaging device 100 is referred to as the first environment measuring means 11A, and the imaging element 3 is further used. The second environmental measuring means 11B is an environmental measuring means capable of measuring a value close to the surface environment.

FIG. 3 shows the image pickup device 100 in which the front curtain 9a of the shutter 9 mounted on the image pickup device 100 described with reference to FIG. 2 is running and the shutter is in the closed state. FIG. 4 is a block diagram showing a schematic configuration of an image pickup apparatus according to an embodiment of the present invention.

In FIG. 4, the image pickup device 100 includes an image sensor 3, a TFT monitor 4, an eye position detecting means 8, an electronic viewfinder 10, a first environment measuring means 11A, a second environment measuring means 11B, a camera microcomputer 21, a ROM 22 and the like. It includes a RAM 23, an image processing unit 25, a recording unit 26, and an operation unit 28.

The camera microcomputer 21 is a microcomputer that controls the system of the image pickup device 100, and is an image pickup element 3, a TFT monitor 4, an electronic viewfinder 10, a first environment measurement means 11A, a second environment measurement means 11B, a ROM 22, and a RAM 23. , The image processing unit 25, the recording unit 26, and the operation unit 28 are connected to perform the processing described later.

The image pickup device 3 is an image pickup device composed of a CCD or CMOS image sensor and its peripheral circuits, and photoelectrically converts a subject image to output an image pickup signal. Various processes are performed on the image pickup signal by the image processing unit 25, which will be described later, to generate an image signal.

The TFT monitor 4 is composed of, for example, a liquid crystal display. The TFT monitor 4 displays image data captured by the image sensor 3, a setting icon of the image pickup device 100, and the like. The operation unit 28 outputs a picture taken by the image sensor 3 and a power ON / OFF switching signal to the camera microcomputer 21.

The eye position detecting means 8 measures the position of the photographer's eye, and the camera microcomputer 21 calculates the measurement result to determine whether or not the user is using the electronic viewfinder 10. Do.

The first environment measuring means 11A measures the environment when a command for environment measurement is sent from the camera microcomputer 21 described later. The environment here may be temperature, humidity, or both. Then, by transmitting the measurement result to the ROM 22 described later, the information stored as the environmental information of the first environmental measurement means 11A is updated.

Similar to the first environment measurement means 11A, the second environment measurement means 11B also measures the environment when an environment measurement command is sent from the camera microcomputer 21 described later, and transmits the measurement result to the ROM 22 described later. Updates the information stored as the environmental information of the second environmental measuring means 11B.

The ROM 22 and the RAM 23 have an area for holding data. The ROM 22 is a non-volatile memory, and the RAM 23 is a volatile memory. A program for operating the camera microcomputer 21 is recorded in the ROM 22. In these programs, the captured image signal output from the image processing unit 25 is read by the input signal from the operation unit 28 and transferred to the RAM 23, or the data is transferred from the RAM 23 to the TFT monitor 4 and the electronic viewfinder 10. There is a process, a process of PEG-compressing image data and storing it in a recording unit 26 in a file format. In the case of moving image data, the same processing is performed, the data is compressed into a MOV format file, and the moving image data is stored in the recording unit 26. Further, the camera microcomputer 21 instructs the image processing unit 25 to change the number of data acquisition pixels and the digital image processing.

The RAM 23 includes an image development area 23a, a work area 23b, a VRAM 23c, and a temporary evacuation area 23d. The image development area 23a is used as a temporary buffer for temporarily storing the captured image (YUV digital signal) sent from the image processing unit 25 and the JPEG compressed image data read from the recording unit 26. .. Alternatively, it is used as an image-only work area for image compression processing and decompression processing.

The work area 23b is a work area for various programs. The VRAM 23c is used as a VRAM for storing display data to be displayed on the TFT monitor 4. Further, the temporary evacuation area 23d is an area for temporarily evacuating various data.

The recording unit 26 is a flash memory for storing captured image data JPEG-compressed by the camera microcomputer 21 or MOV format moving image data in a file format. Examples of the recording unit 26 include an SD card, a FLASH memory, and a hard disk.

The image processing unit 25 resizes the image data generated by the image sensor 3, corrects the brightness, compresses the image, and outputs the image data to the recording unit 26.

The electronic viewfinder 10 processes the signal photoelectrically converted by the image sensor 3 in the image processing unit 25, and outputs an image from the camera microcomputer 21 to see the image of the field being photographed through the eyepiece frame. It is intended to enable the display of captured image data and shooting information.

Hereinafter, the first embodiment of the present invention will be described with reference to FIG.

First, in step S100, the camera microcomputer 21, the first environmental measuring means 11A, and the second environmental measuring means 11B are energized.

In step S101, it is determined whether or not the embodiment, for example, the "condensation prevention mode" is turned on. The ON / OFF of the mode may be set by the user or may be set in advance in the image pickup apparatus. If the "condensation prevention mode" is OFF, the flow ends. If it is ON, the process proceeds to S102.

In step S102, the measurement result 11a of the first environmental measuring means 11A is confirmed. In the embodiment, the temperature measurement result of the first environmental measuring means 11A is confirmed.

In step S103, the measurement result 11b of the second environment measuring means 11B is confirmed. In the embodiment, the temperature measurement result of the second environmental measuring means 11B is confirmed.

In step S104, it is determined whether or not the measurement result 11b of the second environment measuring means 11B is larger than the threshold value B. Here, the threshold value B is mainly a function of the measurement result 11a. The smaller the value of the measurement result 11a, the lower the value of the threshold value B. The absolute value of the threshold value B is a value determined in consideration of the material of each unit constituting the image pickup apparatus, the arrangement of the units, and the like.

When the measurement result 11b is larger than the threshold value B, it is determined that the concern about dew condensation is low, and the process proceeds to step S105. If it is determined that the threshold value is smaller than the threshold value B, the process proceeds to step S110, and the operation of step 110 described later is performed.

The measurement result 11a is confirmed again in step S105.

In step S106, it is confirmed whether or not the measurement result 11a has changed. If there is no change, the process proceeds to step S105, and steps S105 and S106 are repeated until a change in the measurement result 11a is confirmed. When the change in the measurement result 11a is confirmed, the process proceeds to step S107.

In step S107, it is determined whether or not the rate of change of the measurement result 11a is larger than the threshold value A. Here, the threshold value A is determined by the material of each unit constituting the image sensor, the measurement result 11a, and the measurement result 11b, but in addition to this, the first environment measurement means 11A and the second environment measurement It can be determined in consideration of the arrangement of each unit such as the means 11B and the image pickup element 3, and the determinant of the threshold value A is not limited to the above. The value of the threshold value A may be stored in the imaging device in advance, but may be determined by the user according to his / her preference.

As a result of determining the magnitude of the change rate of the measurement result 11a, if the change rate of the measurement result 11a is smaller than the threshold value A, it is determined that the possibility of dew condensation is low, and the process returns to step S105 again. If the rate of change of the measurement result 11a is larger than the threshold value A, the process proceeds to step S108.

In step S108, the measurement result 11b is confirmed, and the process proceeds to step S109.

In step S109, it is determined whether or not the measurement result 11b is smaller than the above-mentioned threshold value B. If the result of the measurement result 11b is larger than the threshold value B, the process proceeds to step S105.

If the result of the measurement result 11b is smaller than the threshold value B, it is determined that there is a high possibility of dew condensation, and the process proceeds to step S110.

In step S110, the shutter 9 is closed. Specifically, the front curtain 9a is run so that the image sensor 3 is not exposed. The rear curtain 9b may or may not be run.

This makes it possible to prevent the atmosphere around the image pickup device from coming into direct contact with the surface of the image pickup device 3 in the normally open type image pickup device. From this, it is possible to prevent dew condensation on the surface of the image pickup image element 3 when the surrounding environment of the image pickup apparatus changes, mainly even when the environment changes from a low temperature environment to a high temperature environment. Further, even if dew condensation occurs on the surface of the image sensor 3, it is possible to prevent dust and the like floating in the atmosphere in front of the image sensor 3 from entering the generated dew condensation particles.

As a result, the amount of dust that is aggregated due to the volatilization of the dew condensation particles can be reduced, and the image sensor 3 can be prevented from being soiled.

After the process of step S110, the process proceeds to step S111.

In step S111, it is determined whether or not there is a return instruction. The return instruction here includes various signals from the operation unit 28, but is not limited to this.

If there is no return instruction in step 111, the process waits until there is a return instruction. If there is a return instruction, the process proceeds to step S112.

In step S112, the shutter 9 is opened.
As a result, the field light can be acquired by the image sensor 3, and the image pickup operation can be prepared.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG.

First, in step S200, the camera microcomputer 21, the first environmental measuring means 11A, and the second environmental measuring means 11B are energized in the same manner as in step S100 of FIG.

In step S201, the same process as in step S101 in FIG. 1 is performed. Specifically, it is determined whether or not the embodiment, for example, the "condensation prevention mode" is ON. The ON / OFF of the mode may be set by the user or may be set in advance in the image pickup apparatus. If the "condensation prevention mode" is OFF, the flow ends. If it is ON, the process proceeds to S202.

In step S202, the measurement result 11a of the first environmental measuring means 11A is confirmed. In the embodiment, the absolute humidity measurement result of the first environmental measuring means 11A is confirmed.

In step S203, the measurement result 11b of the second environment measuring means 11B is confirmed. In the embodiment, the temperature measurement result of the second environmental measuring means 11B is confirmed.

In step S204, it is determined whether or not the measurement result 11a is larger than the threshold value C. Here, the threshold value C is the value of the saturated water vapor amount at the temperature of the measurement result 11b.

If it is determined in step S204 that the measurement result 11a is smaller than the threshold value C, the process proceeds to step S202, and the processes of steps S202, S203, and S204 are performed until the measurement result 11a is determined to be larger than the threshold value C in step S204. repeat. If it is determined in step S204 that the measurement result 11a is larger than the threshold value C, the process proceeds to step S205.

In step S205, the shutter 9 is closed in the same manner as in S110 of the first embodiment. Since the effect of this is the same as that of step S110 in the first embodiment, the description thereof will be omitted.

In the next step, S206, it is confirmed whether or not there is a return instruction in the same manner as in step S111 in the first embodiment. In the step here, the input of the eye detecting means 8 is mentioned as the return instruction, but the return instruction is not limited to this as in step S111 of the first embodiment. If there is no return instruction, wait until there is a return instruction. If there is a return instruction, the process proceeds to step S207.

In step S207, the shutter 9 is opened in the same manner as in step S112 in the first embodiment. Since the effect is the same as that of step S112 in Example 1, the description thereof will be omitted.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

3 image sensor, 9 mechanical shutter mechanism,
11A first environment detection means, 11B second environment detection means,
11a first environment detection result, 11b second environment detection result,
100 Imaging device

Claims (2)

It is provided with an image sensor, a mechanical shutter mechanism on the subject side of the image sensor, and at least two temperature detecting means.
The surface of the image sensor is shielded by the mechanical shutter mechanism by the first temperature detection result obtained from the first temperature detecting means and the second temperature detection result obtained from the second temperature detecting means. An image pickup apparatus characterized in that it switches between an open state and a closed state in which the surface of the image pickup element is shielded by the mechanical shutter mechanism. An image sensor, a mechanical shutter mechanism on the subject side of the image sensor, and
Equipped with humidity detection means and temperature detection means,
The humidity detection result obtained from the humidity detection means, the open state in which the surface of the image sensor is not shielded by the mechanical shutter mechanism based on the temperature detection result obtained from the temperature detection means, and the surface of the image sensor are mechanical. An image sensor characterized by switching between a closed state, which is shielded by a shutter mechanism, and a closed state.

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