JP2006091505A - Focal plane shutter and substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focal plane shutter having a substrate superior in wear resistance and corrosion resistance. <P>SOLUTION: The focal plane shutter includes a front curtain 10 having blades 11 to 14 and a rear curtain 20 having blades 21 to 24. A rear curtain arm 26 pivotally supports the blades 21 to 24 turnably through connection pins 27a to 27d, and a first substrate 30 having an opening 30a is disposed in parallel with and adjacently to a turning trajectory surface of the rear curtain arm 26 and has a nickel plating layer 2 and a black oxide layer 3 formed on a surface A thereof to suppress progress of wear and has the surface of the black oxide layer 3 treated by sand blasting to enhance the corrosion resistance of the substrate. A surface B of a second substrate 31 is treated in the same manner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a focal plane shutter of a camera or a digital camera using a silver salt film.

  In a general focal plane shutter, a plurality of light shielding blades are rotatably attached to an arm via connecting pins. In accordance with the rotation of the arm, the plurality of light shielding blades travel along the surface of the substrate having the opening, and perform the opening / closing operation of the opening. The substrate having an opening is usually an aluminum alloy that has been anodized. Further, in the lens shutter, a shutter drive system is attached to the shutter base plate, and an opening formed in the central portion of the optical axis of the shutter base plate is opened and closed by rotationally driving shutter blades by the shutter drive system. The shutter base plate is subjected to electrodeposition coating using an electrodeposition paint containing an antireflection filler or a slidable filler in an electrodepositable resin. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 11-64925 (pages 2, 3 and 6; FIGS. 8 and 9)

  In a conventional anodized and matte-coated substrate, when the end of the connecting pin slides on the surface of the substrate, the surface wears and the coefficient of friction changes, so the curtain speed (blade traveling speed) The shutter accuracy will deteriorate. By applying electrodeposition coating to the substrate using the technique of Patent Document 1, the surface becomes difficult to wear and the shutter accuracy is stabilized. However, since the electrodeposition coating film contains a large amount of filler, it becomes porous. And the like easily penetrate into the substrate and cause corrosion of the substrate.

(1) In order to solve the above-described problem, a focal plane shutter according to a first aspect of the present invention is configured to rotate a front curtain and a rear curtain each having a plurality of light shielding blades and a plurality of light shielding blades via a connecting pin. An arm member that is pivotally supported, and a substrate having an opening disposed in parallel with and adjacent to the rotation trajectory plane of the arm member, the substrate being formed on the nickel plating layer and the nickel plating layer It has a black oxide layer, and the surface of the black oxide layer is finished to a predetermined surface roughness by a mechanical processing method.
(2) The focal plane shutter of the invention according to claim 2 is the focal plane shutter according to claim 1, wherein the substrate is finished to a predetermined surface roughness by an abrasive spraying method as a mechanical processing method. preferable.
A focal plane shutter according to a third aspect of the present invention is the focal plane shutter according to the first or second aspect, wherein the substrate has a reflectance equivalent to a surface whose end face of the opening faces the rotation trajectory surface of the arm member. It is preferable that it is finished.
(3) A substrate having an opening according to a fourth aspect of the invention is used for the focal plane shutter according to any one of the first to third aspects.

  According to the present invention, the surface of the black oxide layer is finished to a predetermined surface roughness by a mechanical processing method, so that fine holes are sealed, moisture does not penetrate into the substrate, and the corrosion resistance of the substrate is improved. To do.

Hereinafter, a focal plane shutter according to the present invention will be described with reference to FIGS. In the figure, the same components are denoted by the same reference numerals.
FIG. 1 is an exploded perspective view of a focal plane shutter, showing the positional relationship of each component. A light shielding plate 41 and an intermediate plate 42 are disposed between the first substrate 30 located on the lens side and the second substrate 31 located on the film side or the image sensor side. Further, the spacer 43 and the rear curtain 20 are accommodated between the first substrate 30 and the light shielding plate 41, and the spacer 44 and the front curtain 10 are accommodated between the intermediate plate 42 and the second substrate 31. Yes.

  The front curtain 10 includes four light shielding blades 11 to 14, a front curtain main arm 16, and a front curtain slave arm 15. The rear curtain 20 includes four light shielding blades 21 to 24, a rear curtain main arm 26, and a rear curtain secondary arm 25. The front curtain main arm 16 has bearing holes 16a and 16b and four connection holes, and the front curtain slave arm 15 has a bearing hole 15a and four connection holes. The rear curtain main arm 26 has bearing holes 26a and 26b and four connection holes, and the rear curtain slave arm 25 has a bearing hole 25a and four connection holes.

  In the first substrate 30 and the second substrate 31, openings 30a and 31a are provided at corresponding positions, respectively. Further, the first substrate 30 and the second substrate 31 are provided with arc grooves 30b, 30c and 31b, 31c, respectively, at corresponding positions. The light shielding plate 41 and the intermediate plate 42 are provided with openings 41a and 42a at positions corresponding to the openings 30a and 31a, respectively.

  Next, the configuration and operation of the shutter of the present invention will be described with reference to FIGS. FIG. 2 is a front view of the focal plane shutter with the shutter charged. FIG. 3 is a front view of the focal plane shutter in a state where the shutter has finished the exposure operation. 2 and 3, the illustration is omitted except for the front curtain 10, the rear curtain 20, and the first substrate 30, and the first substrate 30 located in the foreground is indicated by a one-dot chain line.

  In FIG. 2, the light-shielding blades 11 to 14 of the front curtain 10 are in a shielded state to unfold and cover the opening 30a of the first substrate 30, and the light-shielding blades 21 to 24 of the rear curtain 20 overlap above the opening 30a. Thus, the opening 30a is opened. That is, the front curtain 10 is shielded and the rear curtain 20 is open, thereby preventing exposure.

  In FIG. 3, the light shielding blades 11 to 14 of the front curtain 10 are in an open state in which the opening 30 a is opened overlapping the lower side of the opening 30 a, and the light shielding blades 21 to 24 of the rear curtain 20 are unfolded to open the opening 30 a. Covered. That is, the front curtain 10 is in the open state and the rear curtain 20 is in the blocked state, thereby preventing exposure.

  As shown in FIGS. 2 and 3, the rotation axes X1 and X2 are implanted in the first substrate 30 and pass through the hole 15a of the front curtain secondary arm 15 and the hole 16a of the front curtain main arm 16, respectively. . The front curtain slave arm 15 and the front curtain main arm 16 are rotatably attached to the rotation shafts X1 and X2, respectively, and constitute a parallel link mechanism. The drive pin 51 is provided in a drive mechanism (not shown) attached to the lens side of the first substrate 30 and passes through the arc groove 30 b and the hole 16 b of the front curtain main arm 16.

  Similarly, the rotation axes X3 and X4 are implanted in the first substrate 30 and pass through the hole 25a of the rear curtain follower arm 25 and the hole 26a of the rear curtain main arm 26, respectively. The rear curtain follower arm 25 and the rear curtain main arm 26 are rotatably attached to the rotation axes X3 and X4, respectively, and constitute a parallel link mechanism. Similarly to the drive pin 51, the drive pin 52 is provided in a drive mechanism (not shown) and passes through the circular arc groove 30 c and the hole 26 b of the rear curtain main arm 26.

  The leading blade main arm 16 and the leading blade slave arm 15 respectively have four connecting holes (such as 17a to 17d in FIG. 4) passing through four connecting holes and rotatably support the four light shielding blades 11 to 14. Yes. Similarly, the rear curtain main arm 26 and the rear curtain follower arm 25 have four connecting holes (such as 27a to 27d in FIG. 4) passed through the four connecting holes so that the four light shielding blades 21 to 24 can rotate. I support.

  Here, the front curtain 10 and the rear curtain 20 will be described in detail with reference to FIG. FIG. 4 is a cross-sectional view taken along the line II in FIG. 2. In order to clarify the positional relationship of each component, the front curtain 10 is sequentially provided with four connecting holes of the rotation axis X2 and the front curtain main arm 16. The rear curtain 20 is represented by a cross section in which the rotation shaft X4 and the four connecting holes of the rear curtain main arm 26 are sequentially connected.

  As shown in FIG. 4, the four connecting pins 17 a to 17 d penetrate the four connecting holes of the leading curtain main arm 16 and are connected to the light shielding blades 14, 13, 12, and 11, respectively. Similarly, the four connecting pins 27a to 27d pass through the four connecting holes of the rear curtain main arm 26, and are connected to the light shielding blades 24, 23, 22, and 21, respectively. The connecting pins 17a to 17d and 27a to 27d are made of stainless steel and are painted black. For the connection, for example, caulking is used. The leading blade main arm 16 and the connecting pins 17a to 17d are adjacent to the surface B of the second substrate 31, and the trailing blade main arm 26 and the connecting pins 27a to 27d are adjacent to the surface A of the first substrate 30. Yes.

  Although not shown, in a cross section in which the four connecting holes of the rotation axis X1 and the front curtain follower arm 15 are sequentially connected and in a cross section in which the rotation shaft X3 and the four connection holes of the rear curtain follower arm 25 are sequentially connected. Is the same configuration. The front curtain follower arm 15 and its connection pin are adjacent to the surface B of the second substrate 31, and the rear curtain follower arm 25 and its connection pin are adjacent to the surface A of the first substrate 30.

The operation of the focal plane shutter configured as described above will be described. This operation is a process of shifting from the state of FIG. 2 to the state of FIG. 3, and is called an exposure operation.
The drive pin 51 moves downward along the arc groove 30b of the first substrate 30 by the drive mechanism described above. As a result, the front curtain follower arm 15 and the front curtain main arm 16 rotate, and the light-shielding blades 11 to 14 of the front curtain 10 start to travel downward from the opening 30a from the deployed state, and the exposure operation starts.

  The drive pin 52 moves downward along the arc groove 30 c of the first substrate 30 after a predetermined time corresponding to the shutter speed from the start of running of the light shielding blades 11 to 14. As a result, the rear curtain follower arm 25 and the rear curtain main arm 26 rotate, and the light-shielding blades 21 to 24 of the rear curtain 20 start to travel downward from the opening 30a from the state of being superimposed above the opening 30a. Deploy and shield the opening 30a. The exposure operation ends when the light shielding blades 21 to 24 completely shield the opening 30a.

  The drive pins 51 and 52 are braked by a brake mechanism (not shown) near the end of the traveling operation of the light shielding blades 11 to 14 and the light shielding blades 21 to 24, respectively. When the charging operation is performed by a charging mechanism (not shown) after the exposure operation is completed, the state shown in FIG. 3 returns to the state shown in FIG.

  Referring to FIG. 4 again, in the above-described exposure operation, the surface A on the connection pin side of the first substrate 30 inevitably comes into contact with the connection pins 27a to 27d. Similarly, contact with the connection pins 17a to 17d is also unavoidable on the surface B of the second substrate 31 on the connection pin side. Therefore, the surfaces A and B are subjected to an abrasion action due to sliding of the connecting pin.

  In the focal plane shutter of the present embodiment, the progress of wear is suppressed by forming the nickel plating layer 2 and the black oxide layer 3 on the first substrate 30 and the second substrate 31, and the black oxide layer 3 is suppressed. The surface of the substrate is sandblasted to improve the corrosion resistance of the substrate.

  FIG. 5 is a partial cross-sectional view schematically showing a cross section cut at a right angle to the surface A of the first substrate 30. FIG. 5 (a) shows a state before sandblasting, and FIG. 5 (b) shows a state after sandblasting. As shown in FIG. 5A, the base material 1 is a flat plate of an aluminum alloy, a nickel plating layer 2 having a thickness of about 5 μm is formed on the surface of the base material 1, and the surface of the nickel plating layer 2 is thin. A black oxide layer 3 of 1 μm or less is formed. The nickel plating layer 2 has high hardness, high toughness, and high lubricity, and is formed by an electroless plating method. The electroless plating method has a higher uniformity in the thickness of the plating layer than electroplating. The black oxide layer 3 is formed for the purpose of preventing reflection by blackening, and is formed by oxidizing the upper surface of the nickel plating layer 2 with a strong acid solution.

  In addition, the nickel plating layer 2 and the black oxide layer 3 have countless pinholes p1 to p3 in various fine forms generated in the process of forming the black oxide layer 3. The pinhole p1 is generated only in the black oxide layer 3, the pinhole p2 is generated from the black oxide layer 3 to the nickel plating layer 2, and the pinhole p3 is generated in the black oxide layer 3. To the aluminum alloy substrate 1 through the nickel plating layer 2. Actually, there is almost no large pinhole such as the pinhole p3, and most of the pinholes p1 and p2. The diameter of the opening of the pinholes p1 to p3 is 1 μm or less even in the largest pinhole p3. If such large and small pinholes p <b> 1 to p <b> 3 exist, moisture or the like enters and causes the base material 1 to corrode.

  As shown in FIG. 5B, the black oxide layer 3 becomes a surface A ′ having a larger surface roughness than the surface A by sandblasting. The average surface roughness of the surface A ′ is about 1 to 1.5 μm. Sand blasting is a mechanical processing method in which abrasive grains are sprayed from the spray nozzle onto the surface of the black oxide layer 3, so that the surface layer of the black oxide layer 3 is plastically deformed as shown in FIG. There exists an effect | action (sealing effect | action) which plugs opening of -p3. Accordingly, it is possible to prevent moisture and the like from entering through the pinholes p1 to p3 and corrode the base material 1, thereby improving the corrosion resistance of the substrate.

FIG. 6 is a perspective view schematically showing sandblasting of the first substrate 30 of the focal plane shutter according to the present embodiment. The first substrate 30 is held by a holder 101, and the abrasive grains in the injection nozzle 102 are sprayed from a direction substantially perpendicular to the surface of the first substrate 30 to process the surface A facing the nozzle injection port. . The sandblasting conditions are, for example, spraying ceramic abrasive grains for 1 to 5 minutes at a projection pressure of ^{3 to} 10 kg / cm ² . The purpose of this sandblasting is not to scrape the black oxide layer 3 but to cause micro plastic deformation on the surface of the black oxide layer 3, and the nickel plating layer 2 is hardly exposed. The processed surface A ′ is kept black.

  Further, since the thickness of the first substrate 30 is as thin as about 0.5 mm, the end surface of the opening 30a has almost the same surface roughness as the surface A ′ of the first substrate 30 due to the wrapping of the abrasive grains to be injected, and is almost equal. The reflectance is as follows. When the sandblasting for one substrate is completed, the spray nozzle 102 is moved in the x direction to process the next substrate. In addition, as a mechanical processing method, it can replace with sandblasting and can also use the processing method which presses and rubs a brush and sandpaper.

As described above, the performance of the first substrate 30 on which the surface layer is formed and subjected to the sandblasting will be described.
About corrosion resistance, the salt spray test and chlorine gas exposure test based on JIS were conducted, and the corrosion incidence rate was investigated. A corrosion test was performed simultaneously with the first substrate 30 using the substrate R having the same size and shape as the first substrate 30 and having the black oxide layer 3 as a comparative example. The corrosion rate of the first substrate 30 is 0% in both the salt spray test and the chlorine gas exposure test, and the substrate R of the comparative example is 0.3% in the salt spray test and 0.4% in the chlorine gas exposure test. %Met. Thus, corrosion resistance improves by performing sandblasting.

  About the reflectance, the 1st board | substrate 30 was 0.9 to 1.0%, and the board | substrate R of the comparative example was 1.5 to 2.0%. The reflectivity of the first substrate 30 is the same value as the reflectivity of the matte coating product, and if the sandblasting is performed, the matte coating process can be omitted from the point of antireflection.

  As described above, the first substrate 30 of the focal plane shutter according to the present embodiment is subjected to sandblasting, whereby the corrosion resistance of the substrate is improved and the reflectance equivalent to that of a matte coated product can be obtained. The matte painting process can be omitted. Since the black oxide layer 3 and the nickel plating layer 2 are made of a material having a small frictional force with the connecting pin, the stability of the curtain speed is maintained.

  In the present embodiment, the example in which the nickel plating layer 2 and the black oxide layer 3 are provided on the surface A of the first substrate 30 and the surface of the black oxide layer 3 is sandblasted has been described. The same processing is performed on the surface B. Further, the formation of the nickel plating layer 2 and the black oxide layer 3 and the sandblasting may be performed on the entire front and back surfaces of the substrate in addition to the surface on the connecting pin side such as the surface A or B. In any case, the sandblasting is performed according to the formation region of the black oxide layer 3. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a disassembled perspective view of the focal plane shutter which concerns on embodiment of this invention. It is a front view of a focal plane shutter in the state where the shutter concerning an embodiment of the invention was charged. It is a front view of a focal plane shutter in a state where the shutter according to the embodiment of the present invention has finished the exposure operation. It is II sectional drawing of FIG. It is a fragmentary sectional view showing typically a perpendicular section of a substrate of a focal plane shutter concerning an embodiment of the invention. FIG. 5 (a) shows a state before sandblasting, and FIG. 5 (b) shows a state after sandblasting. It is a perspective view which shows typically the mode of the sandblasting process with respect to the board | substrate of the focal plane shutter which concerns on this Embodiment.

Explanation of symbols

1: base material 2: nickel plating layer 3: black oxide layer 10: front curtain 11-14: light shielding blade 15: front curtain secondary arm 16: front curtain main arm 17a-17d: connecting pin 20: rear curtain 21-24 : Shading blade 25: Rear curtain follower arm 26: Rear curtain main arm 27 a to 27 d: Connection pin 30: First substrate 31: Second substrate A, A ′, B: Surface p1 to p3: Pinhole 101: Holder 102 : Injection nozzle

Claims (4)

A front curtain and a rear curtain each having a plurality of light shielding blades;
An arm member that pivotally supports the plurality of light shielding blades via a connecting pin; and
A substrate having an opening arranged parallel to and adjacent to the rotation trajectory plane of the arm member,
The substrate has a nickel plating layer and a black oxide layer formed on the nickel plating layer, and the surface of the black oxide layer is finished to a predetermined surface roughness by a mechanical processing method. Features a focal plane shutter. The focal plane shutter according to claim 1,
The focal plane shutter, wherein the substrate is finished to a predetermined surface roughness by an abrasive spraying method as the mechanical processing method. The focal plane shutter according to claim 1 or 2,
The focal plane shutter, wherein the substrate is finished so that an end surface of the opening has a reflectance equivalent to a surface facing the rotation locus surface of the arm member.   A substrate having an opening, which is used in the focal plane shutter according to claim 1.

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