JP2007183407A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively suppress charging, then, to prevent dust from entering and sticking, even though an imaging apparatus uses resin material, not metal material, when the lens unit interchangeable imaging apparatus equipped with a movable mirror that reciprocates between a finder observation position and a photographing retraction position. <P>SOLUTION: By molding the main mirror holding member 41 for holding a main mirror 7 constituting the movable mirror and a sub mirror holding member 63 for holding a sub mirror 62 constituting the movable mirror of resin material with surface active (antistatic agent) mixed, the generation of static electricity by peel-electrification is prevented. Further, the surfaces of the main mirror 7 and the sub mirror 62 formed of optical glass are coated with surface active agent diluted with volatile liquid such as alcohol, and the surface active agent film is formed on the surface of each mirror. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image pickup apparatus such as a single-lens reflex camera with a replaceable lens unit, and more particularly to an image pickup apparatus that has been subjected to antistatic treatment to prevent dust adhesion.

  It is generally known to perform antistatic treatment as a dust adhesion prevention technique. For example, Patent Document 1 proposes that an antistatic treatment is performed to prevent dust adhesion in a small and thin imaging device suitable for being incorporated in a portable terminal.

JP 2005-86746 A

  However, the image pickup apparatus disclosed in Patent Document 1 presents a general technique in which an antistatic process is performed on a member surrounding the image pickup element in order to prevent dust from entering the image pickup apparatus during assembly and entering dust. I'm just doing it.

  In a single-lens reflex camera in which the lens unit can be exchanged, dust adhesion is regarded as a problem. In some cases, dust adhering to the vicinity of the focusing plate constituting the finder can be seen as a finder image. Furthermore, in a digital single-lens reflex camera, dust adhering to the vicinity of the image sensor may appear in the captured image.

  In a single-lens reflex camera with a replaceable lens unit, even if a product is shipped after being strictly controlled in the manufacturing process, dust may adhere in the process of use by the user. For example, when the lens unit is removed from the camera mount in order to replace it, the mirror box may be exposed to the outside air through the camera mount opening and dust may enter.

  As a result of experiments conducted by the inventors of the present application, when a photographing operation is performed, the movable mirror is charged, and when the lens unit is detached from the camera body, dust is sucked into the mirror box from the camera mount opening. Turned out to be. Specifically, it has been confirmed that when the movable mirror moves away from the stopper member in order to reciprocate between the finder observation position and the photographing retreat position, a peeling charging phenomenon occurs and is charged.

  This charging phenomenon is prominent when the movable mirror and the stopper member are made of plastic resin. If the movable mirror and the stopper member are made of metal, the charging phenomenon can be suppressed, but this causes an increase in cost and weight.

  The above-mentioned Patent Document 1 does not disclose any problems inherent in the single-lens reflex camera in which the lens unit as described above can be replaced, and countermeasures thereof.

  The present invention has been made in view of the above points, and is an imaging device in which a lens unit is replaceable, and includes a movable mirror that reciprocates between a finder observation position and a photographing retraction position. The object is to prevent dust from entering and adhering by effectively suppressing charging while using a resin material instead of a metal material.

An imaging apparatus according to the present invention is an imaging apparatus in which a lens unit is replaceable, and includes a movable mirror that reciprocates between a finder observation position and a photographing retreat position, and the movable mirror includes a mirror member and a holding member, The holding member is characterized in that it is molded from a resin material mixed with a surfactant.
Another imaging device according to the present invention is an imaging device in which a lens unit is replaceable, and includes a movable mirror that reciprocates between a finder observation position and a photographing retraction position, and the movable mirror is configured by a mirror member and a holding member. A feature is that a surfactant film is formed on the surface of the mirror member.
Another imaging device according to the present invention is an imaging device in which a lens unit is replaceable, and includes a movable mirror that reciprocates between a finder observation position and a photographing retraction position, and the movable mirror is configured by a mirror member and a holding member. The holding member is formed of a resin material mixed with a surfactant, and a surfactant film is formed on the surface of the mirror member.

  According to the present invention, when the lens unit is an exchangeable imaging device and includes a movable mirror that reciprocates between the viewfinder observation position and the imaging retreat position, the movable mirror holding member is mixed with the surfactant. By using a molded resin material or forming a surfactant film on the surface of the mirror member of the movable mirror, it is possible to effectively suppress charging while using a resin material instead of a metal material. Ingress and adhesion can be prevented. Accordingly, it is possible to avoid an increase in cost and an increase in weight, and it is possible to prevent dust from appearing as a viewfinder image and dust from being reflected in a captured image in a digital single-lens reflex camera.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of a digital single-lens reflex camera according to an embodiment to which the present invention is applied. In FIG. 1, reference numeral 1 denotes a camera body. Reference numeral 2 denotes a release button for instructing photographing.

  3 is a built-in strobe, 4 is a strobe tension hook, and 5 is a strobe tension section. Shown is a state (pop-up state) in which the built-in flash 3 is moved to the light emitting position. The built-in strobe 3 is urged in the direction of the light emission position by a strobe up spring (not shown), and is held by the strobe tensioning hook 4 being locked to the strobe tensioning part 5 at the storage position.

  Reference numeral 6 denotes a mirror box, which is configured to surround the space driven by the main mirror 7 in the direction of the photographing optical axis. Usually, a process such as providing a light shielding paper on the surface is performed so that the photographing light flux does not cause internal reflection. Reference numeral 7 denotes a main mirror for reflecting and guiding the photographing light beam to the finder optical system.

  2 is a front view showing the internal mechanism of the digital single-lens reflex camera with the exterior parts removed, and FIG. 3 is a perspective view. FIG. 4 is an exploded perspective view of the main unit of the internal mechanism. The same components as those in FIG. 1 will be described with the same reference numerals.

  2 to 4, reference numeral 8 denotes a pentamirror that reflects the photographing light beam reflected by the main mirror 7 further to the eyepiece, and is usually configured by bonding a prism or a mirror. Reference numeral 9 denotes a main base plate for fixing and supporting a structural body such as the mirror box 6 and exterior parts, and is formed by press working or the like.

  A motor 10 drives the main mirror 7, pops up the built-in strobe 3, and charges the shutter blades of the shutter unit 12. Its output shaft is connected to a gear train section described later. Reference numeral 11 denotes a motor base plate, and the motor 10 is fixed to the side surface of the mirror box 6 via the motor base plate 11. Reference numeral 12 denotes a shutter unit.

  Reference numeral 13 denotes a battery storage portion for storing the battery 14, and is fixed to the main base plate 9. A battery 14 is detachable from the camera body 1 and is in a state of being stored in the battery storage unit 13 in the illustrated example.

  The motor 10 is arranged on the upper part of the battery storage unit 13 so that the output axis is orthogonal to the mirror box 6, that is, in the direction orthogonal to the photographing optical axis. The outer shape of the motor 10 is a substantially oval shape that follows the upper surface of the battery housing 13. By adopting such a motor 10, it is possible to narrow the gap between the output shaft of the motor 10 and the upper surface of the battery storage unit 13.

  FIG. 5 is an exploded perspective view showing a detailed configuration around the mirror box 6. The main mirror holding member 41 is a member that holds the main mirror 7 and is driven integrally with the main mirror 7.

  The shutter blade 45 in the shutter unit 12 is urged by a spring (not shown) in the traveling direction during exposure, and performs an opening / closing operation by a charge operation and a spring release operation described later.

  FIG. 5 shows a strobe gear unit 55 including a strobe tensioning hook 4 that is not shown in FIGS. 2 to 4. The strobe gear unit 55 transmits the driving force of the motor 10 and opens the strobe tensioning hook 4 that holds the built-in strobe 3 biased by a spring (not shown) in the pop-up direction at the retracted position. It is a popup.

  6 to 8 are diagrams for explaining the operation of the gear arranged on the side surface of the mirror box 6. Reference numeral 21 denotes a pinion gear, which is fixed to the output shaft of the motor 10. Reference numeral 22 denotes a motor reduction gear that transmits a motor driving force to the sun gear 23. 23 is a sun gear. Reference numeral 24 denotes a planetary gear that revolves around the sun gear 23 within a predetermined angle range.

  25 is a mirror reduction gear, 26 is a mirror transmission gear, and 27 is a mirror cam gear. The mirror drive lever 30 is driven by these gears 25, 26, 27, and the main mirror 7 reciprocates up and down. The mirror up spring 32 and the mirror down spring 33 are urged in the respective directions according to the driving state.

  28 is a shutter transmission gear, and 29 is a shutter cam gear. The shutter blade 45 is opened and closed by the driving force of the motor 10 via the gears 28 and 29 and the action of the shutter drive lever 31 and the shutter drive lever spring 34.

  The gears and levers other than the pinion gear 21 are rotatably supported on shafts formed integrally with the mirror box 6 except for the planetary gear 24, and are motor-supported by screws on the mirror box 6. 11.

  Next, a flow of a series of operations of the digital single-lens reflex camera will be described with reference to FIGS. 6 shows a standby state, FIG. 7 shows a mirror-up state, and FIG. 8 shows a strobe-up drive state.

  The standby state shown in FIG. 6 is a state in which mirror down and shutter charge are completed. The mirror drive lever 30 is urged by the mirror up spring 32 in the mirror up direction, in the clockwise direction in the figure, but is in contact with the cam top phase of the cam portion 27a of the mirror cam gear 27 so that the mirror down state is maintained. keeping.

  The main mirror 7 is held by a main mirror holding member 41, and the main mirror holding member 41 is pivotally supported with respect to the mirror box 6 about a main mirror holding member rotation shaft 42. Since the main mirror holding member drive shaft 43 of the main mirror holding member 41 is sandwiched and held between the mirror drive lever 30 and the mirror down spring 33, the main mirror 7 is moved up by the operation of the mirror drive lever 30. Or mirror down.

  When the photographer presses the release button 2 to give a shooting instruction, the motor 10 is energized so as to rotate in the reverse direction, that is, the pinion gear 21 rotates clockwise. As a result, the driving force is transmitted in the order of the motor reduction gear 22, the sun gear 23, the planetary gear 24, the mirror reduction gear 25, the mirror transmission gear 26, and the mirror cam gear 27, and the mirror cam gear 27 rotates in the clockwise direction. Further, the driving force is transmitted to the shutter transmission gear 28 and the shutter cam gear 29, and the shutter cam gear 29 also rotates in the clockwise direction.

  When the mirror cam gear 27 rotates clockwise, the contact position between the mirror drive lever 30 and the cam portion 27a of the mirror cam gear 29 moves from the cam top to the cam bottom. By this operation, the mirror driving lever 30 is urged by the mirror up spring 32 and thus rotates in the clockwise direction. Thereby, the main mirror holding member drive shaft 43 held between the mirror drive lever 30 and the mirror down spring 33 moves upward, and the main mirror 7 enters the mirror up state. When the mirror up state is completed, energization to the motor 10 is stopped and the motor 10 stops.

  Similarly, the shutter drive lever 31 is rotated clockwise by the clockwise rotation of the shutter cam 29 to drive the shutter unit 12 so that the shutter blades 45 can be exposed.

  The mirror-up state shown in FIG. 7 is a state waiting for exposure running of the shutter blade 45. After the shutter blade 45 is exposed, the motor 10 is energized so as to rotate in the reverse direction. As a result, the mirror cam gear 27 and the shutter cam gear 29 rotate in the clockwise direction as described above.

  When the mirror cam gear 27 rotates clockwise, the contact position between the mirror drive lever 30 and the cam portion 27a of the mirror cam gear 29 moves from the cam bottom to the cam top. By this operation, the mirror drive lever 30 rotates counterclockwise in the figure against the urging force of the mirror up spring 32. As a result, the main mirror holding member drive shaft 43 held between the mirror drive lever 30 and the mirror down spring 33 moves downward, and the main mirror 7 enters the mirror down state.

  Similarly, the shutter drive lever 31 is rotated counterclockwise by the clockwise rotation of the shutter cam 29, drives the shutter unit 12, and resists the biasing spring force of the shutter blade 45 to enter the standby state. To do. When the transition of the shutter unit 12 to the standby state is completed, the energization to the motor 10 is stopped and the motor 10 stops. That is, the standby state shown in FIG. 6 is restored.

  The state shown in FIG. 8 is a strobe up drive state. In the standby state shown in FIG. 6, when the release button 2 is pressed and the CPU (not shown) determines that the built-in strobe 3 needs to emit light depending on the subject condition, or the built-in strobe up (not shown) is taken by the photographer's intention. When the button is pressed, the motor 10 is energized so as to rotate in the forward direction. That is, the pinion gear 21 rotates counterclockwise in the figure, and the driving force is transmitted to the motor reduction gear 22 and the sun gear 23, and the sun gear 23 rotates counterclockwise. Thus, the planetary gear 24 is disengaged from the mirror reduction gear 25, revolves counterclockwise, engages with the strobe reduction gear 51, and transmits the driving force. The strobe reduction gear 51 transmits driving force to the strobe cam gear 52, and the strobe cam gear 52 rotates in the clockwise direction.

  When the strobe cam gear 52 rotates in the clockwise direction, a cam portion (not shown) abuts against the tension hook cam abutting portion 4a of the strobe tensioning hook 4 and pushes down downward, and the strobe tensioning hook 4 rotates counterclockwise. To do. By this operation, the strobe tensioning hook 4 and the strobe tensioning part 5 are unlocked, and the built-in strobe 3 biased in the up direction by a biasing spring (not shown) is pushed up to the light emitting position.

  Next, the configuration of the movable mirror in the digital single-lens reflex camera described above will be described. FIG. 9 is a central cross-sectional view showing the configuration of the digital single-lens reflex camera according to the present embodiment, and FIG. 10 is a view showing the operation range of the main mirror 7 and the sub mirror 62.

  FIG. 9 shows a state in which a lens unit (not shown) is removed. When the lens unit is mounted, the camera unit 61 can be coupled. In the digital single-lens reflex camera of the present embodiment, the movable mirror is constituted by the main mirror 7 held by the main mirror holding member 41 and the sub mirror 62 held by the sub mirror holding member 63.

  As described above, the main mirror holding member 41 is pivotally supported by the mirror box 6 so as to be rotatable about the main mirror holding member rotation shaft 42, and performs an up-down operation by the drive mechanism described above.

  The sub mirror holding member 63 is pivotally supported by the main mirror holding member 41 and operates in conjunction with the movement of the main mirror holding member 41.

  The mirror-down state shown in FIG. 9 is a viewfinder observation state, and a photographing light beam that has passed through a lens unit (not shown) is reflected and separated into a transmitted light beam by a main mirror 7 that is a half mirror. The reflected light beam is guided to the finder, and the transmitted light beam is guided to the AF system. The light beam guided to the finder forms an image on the focus plate 64. The state of the focus plate 64 can be observed by the photographer via the pentamirror 8 and the eyepieces 65 to 67. The light beam guided to the AF system is totally reflected by the sub mirror 62 and guided to the AF sensor 71 through the field lens 68, the total reflection mirror 69, and the secondary imaging lens 70.

  FIG. 10 is a diagram showing the operating range of the main mirror 7 and the sub mirror 62. A shows the viewfinder observation position shown in FIG. 9, and B shows the photographing retreat position. C indicates the turning locus of the tip of the main mirror.

  At the finder observation position A, the main mirror holding member 41 is in contact with the stopper member 72 and positioned. The stopper member 72 is provided integrally with the mirror box 6, but may be configured as a separate part. At this time, the sub mirror holding member 63 is also positioned by a stopper holding member (not shown).

  At the photographing retreat position B, the main mirror holding member 41 is positioned in contact with the stopper member 73. The stopper member 73 is provided on the pentaholder 6. At this time, the sub mirror holding member 63 is positioned by contacting the main mirror holding member 41. The sub mirror holding member 63 is spring-biased to the finder observation position A and the photographing retreat position B by the action of a toggle reversing spring (not shown).

  At the photographing retreat position B, the light beam that has passed through a lens unit (not shown) travels straight and reaches the shutter blade 45 because the movable mirror is retracted. When the shutter blade 45 operates and an opening is formed, the light passes through the optical filter 75 and reaches the image sensor 76. The optical filter 75 is formed by bonding and integrating an optical low-pass filter and an infrared cut filter.

  As described above, it is difficult to reduce the size of the focus plate 64 and the main mirror 7 in a digital single-lens reflex camera equipped with a large image sensor 76. For this reason, it is difficult to increase the distance between the optical filter 75 and the image sensor 76. As a result, the distance between the image sensor 76 and a foreign substance such as dust attached to the optical filter 75 is reduced, and the subject image on the image sensor 76 enters the image without significant blurring of the shadow of the foreign object. An image captured in such a state is a black shadow of a foreign object, and the quality of the image is greatly reduced. Therefore, it is necessary to devise a method for preventing the foreign object from entering the camera.

  Further, even if dust adheres to the focus plate 64, dust is seen in the finder image, so that the quality of the finder is greatly impaired, and some countermeasure is required.

  Further, with respect to the AF system, if dust adheres to the field lens 68, the AF function may be disturbed, and some countermeasure is required.

  As described above, when dust enters the mirror box 6, there is a risk that the quality of the single-lens reflex camera will be significantly degraded. Therefore, in the manufacturing process, under thorough quality control, assembly using a dustproof chamber is performed so as not to leave dust in the mirror box 6, and further thorough dust checking in the final process is performed.

  However, in a single-lens reflex camera in which the lens unit can be replaced, as described above, there is an opportunity to frequently replace the lens unit in the process of being used by the user. When the lens unit is removed, the mirror box 6 is exposed to outside air through the opening of the camera mount 61, and there is a high risk of dust entering.

  Hereinafter, measures for preventing dust from entering the mirror box 6 with the lens unit removed from the camera mount will be described. If it says from a conclusion, generation | occurrence | production of the static electricity in the mirror box 6 is prevented and it is trying to avoid attracting | sucking external dust.

  What should be noted as a cause of generation of static electricity is the main mirror holding member 41 and the sub mirror holding member 63 that constitute the movable mirror. In general, in the case of a single-lens reflex camera with a popular price range, the main mirror holding member 41 and the sub mirror holding member 63 are formed of a plastic resin for the purpose of reducing manufacturing cost and weight. Therefore, when starting up from the mirror-down state and when starting down from the mirror-up state, it was confirmed that a peeling charging phenomenon occurred between the stopper members 72 and 73 and the movable mirror was charged with static electricity. . It has been found that external dust is attracted through the opening of the camera mount 61 due to the occurrence of the peeling charging phenomenon and charging.

  In this case, it is possible to prevent charging by using a lot of metal parts, but this leads to a significant increase in manufacturing cost and an increase in camera weight.

  Therefore, the objective is achieved with the basic configuration using plastic resin. First, the first countermeasure is to mold the main mirror holding member 41 and the sub mirror holding member 63 with a resin material mixed with a surfactant (antistatic agent). In the resin material mixed with the surfactant, the surfactant is bleed to form a conductive layer on the surface, and static electricity can be leaked, and generation of static electricity due to peeling charging can be prevented. As a representative product of such a surfactant, an electro stripper (Kao Corporation) and the like are known.

  In this case, it is preferable to use a polycarbonate resin as the resin material in order to guarantee strength. However, if only the polycarbonate resin is used, the molding temperature is too high and the surfactant may be destroyed. Therefore, it is desirable to blend about 30% of the ABS resin. In order to further ensure the strength, it is more desirable to use a molding material mixed with glass fibers.

  The second countermeasure is to dilute and apply a surface active agent with a volatile liquid such as alcohol on the surface of the main mirror 7 and the sub mirror 62 formed of optical glass to form a surface active agent film on the surface. is there. The dilution ratio of the surfactant is preferably about 50 to 200 times.

In order to make the most effective in the first countermeasure and the second countermeasure described above, the mixing ratio of the surfactant is set so that the surface resistance is 10 ¹² Ω or less as generally known in the literature. It is desirable to adjust.

  Furthermore, in the present embodiment, the mirror box 6, the stopper member 72, the stopper member 73, and the pentaholder 74 are also molded from a resin material mixed with a surfactant to enhance the antistatic effect in the mirror box 6.

  Furthermore, in this embodiment, measures are also taken for locations that directly cause problems when dust adheres. Specifically, a surfactant is diluted with a volatile liquid such as alcohol and applied to the surfaces of the optical filter 75, the focus plate 64, and the field lens 68 to form a surfactant film on the surface.

  As described above, the resin material as the structural material uses a molding material in which a surfactant is mixed to exert an antistatic effect, and the optical member such as a lens has a surfactant on the surface. It is an effective means to form a film and exhibit an antistatic effect.

  In this embodiment, an example in which the present invention is applied to a digital single-lens reflex camera has been described. However, the present invention can also be applied to a single-lens reflex camera using a silver salt film.

1 is a perspective view of a digital single lens reflex camera according to an embodiment. It is a front view which shows the internal mechanism which removed the exterior component of the digital single-lens reflex camera which concerns on embodiment. It is a perspective view which shows the internal mechanism which removed the exterior component of the digital single-lens reflex camera which concerns on embodiment. It is a disassembled perspective view of the main unit of an internal mechanism. It is a disassembled perspective view which shows the structure of the periphery of a mirror box. It is a mirror box side view, Comprising: It is a figure which shows a standby state. It is a mirror box side view, Comprising: It is a figure which shows a mirror up state. It is a mirror box side view, Comprising: It is a figure which shows a strobe up drive state. It is a center sectional view showing the configuration of the digital single-lens reflex camera according to the present embodiment. It is a figure which shows the operation | movement range of a main mirror and a submirror.

Explanation of symbols

6 Mirror box 7 Main mirror 8 Penta mirror 10 Motor 41 Main mirror holding member 42 Main mirror holding member rotating shaft 45 Shutter blade 61 Camera mount 62 Sub mirror 63 Sub mirror holding member 64 Focus plate 65 to 67 Eyepiece 68 Feed lens 71 AF sensor 72 Stopper member 73 Stopper member 75 Optical filter 76 Image sensor

Claims (7)

An imaging device with a replaceable lens unit,
With a movable mirror that reciprocates between the viewfinder observation position and the shooting retreat position,
An image pickup apparatus, wherein the movable mirror includes a mirror member and a holding member, and the holding member is formed of a resin material mixed with a surfactant.   The imaging apparatus according to claim 1, wherein the resin material is a polycarbonate resin containing an ABS resin. An imaging device with a replaceable lens unit,
With a movable mirror that reciprocates between the viewfinder observation position and the shooting retreat position,
An image pickup apparatus, wherein the movable mirror includes a mirror member and a holding member, and a surfactant film is formed on a surface of the mirror member.   The imaging device according to claim 3, wherein the surfactant film is formed by applying a surface active material diluted with a volatile liquid to the surface of the mirror member. An imaging device with a replaceable lens unit,
With a movable mirror that reciprocates between the viewfinder observation position and the shooting retreat position,
The movable mirror includes a mirror member and a holding member, the holding member is formed of a resin material mixed with a surfactant, and a surfactant film is formed on the surface of the mirror member. An imaging device.   At least one of the stopper member with which the movable mirror abuts at the viewfinder observation position and the stopper member with which the movable mirror abuts at the photographing retreat position is formed of a resin material mixed with a surfactant. The imaging apparatus according to claim 1, wherein the imaging apparatus is characterized. The image pickup apparatus according to claim 1, wherein the surface resistance is set to 10 ¹² Ω or less by an antistatic treatment with a surfactant.

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