Light intensity control devices and optical instruments

Abstract

To provide a thin, highly durable light intensity control device. [Solution] To solve the above problems, the light intensity adjustment device of the present invention comprises a ground plate 1 with a passage opening formed therein, A light intensity adjustment device having a light intensity adjustment member that moves forward and backward relative to the light passage opening in accordance with the rotation of a magnet as a driving source, wherein the light intensity adjustment member is configured by arranging a first support member 10, an optical film 12, and a second support member 11 in the order of light passage direction, and the optical film 12 is fixed to at least one of the first support member 10 and the second support member 11.

Description

Technical Field

[0001] The present invention relates to a light quantity adjustment device mounted on an optical device such as an imaging device or an interchangeable lens. Further, it relates to an optical device provided with a light quantity adjustment device.

Background Art

[0002] Conventionally, digital cameras and video cameras that form an image of a subject on an image sensor to obtain image data representing the subject have become widespread. Inside the lens barrel of an optical device such as such a digital camera or video camera, there is a device provided with a light quantity adjustment device such as an optical filter that moves forward and backward to the light passage opening and covers or opens the light passage opening using a moving magnet type electromagnetic drive unit as a drive source (for example, see Patent Document 1).

[0003] In an optical device such as a still camera or video camera provided with such a light quantity adjustment device, it is desired to be able to acquire higher quality image data. Further, miniaturization and thinning have progressed, and miniaturization and thinning are strongly required for the light quantity adjustment device as well.

Prior Art Documents

Patent Documents

[0004] <*

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the optical device as described above, if light is reflected by the light quantity adjustment device disposed inside the lens barrel and the reflected light reaches the image sensor, image quality degradation due to ghost generation or the like will occur. Further, if small scratches or foreign matters are generated by the operation of the light quantity adjustment device, the image quality will be degraded.

[0006] In recent years, image sensors in optical devices such as those mentioned above have evolved to acquire high-quality image data through advancements such as increased pixel density and higher sensitivity. Consequently, light intensity control devices also require more measures than before to address the aforementioned concerns about image quality degradation.

[0007] This product provides a light intensity control device that is easy to miniaturize and thin without compromising the characteristics of conventional products, and also offers high filter durability. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a light intensity adjustment device comprising a base plate having a light passage opening formed therein, and a light intensity adjustment member that moves forward and backward relative to the light passage opening in accordance with the rotation of a magnet as a driving source, wherein the light intensity adjustment member is configured by arranging a first support member, an optical film, and a second support member in the order of light passage direction, and the optical film is fixed to at least one of the first support member and the second support member. [Effects of the Invention]

[0009] To provide a thin, highly durable light intensity control device. [Brief explanation of the drawing]

[0010] [Figure 1] Plan view of the light intensity control device according to Example 1 [Figure 2] Rear view of the light intensity control device according to Example 1 [Figure 3] Exploded perspective view of the light intensity control device according to Example 1 [Figure 4] Exploded perspective view of the light intensity adjustment vane of the light intensity adjustment device according to Example 1 [Figure 5] Internal view of the vane chamber of the light intensity control device according to Example 1, showing the light intensity control vane retracted from the aperture. [Figure 6] Internal view of the vane chamber of the light intensity control device according to Example 1, showing the light intensity control vane entering the aperture. [Figure 7]Internal view of the vane chamber of the light intensity control device according to Example 1, showing the light intensity control vane retracted from the aperture. [Figure 8] Internal view of the vane chamber of the light intensity control device according to Example 1, showing the light intensity control vane entering the aperture. [Figure 9] Optical instrument equipped with a light intensity adjustment device according to Example 2 [Figure 10] Optical instrument equipped with a light intensity adjustment device according to Example 2 [Modes for carrying out the invention]

[0011] (Example 1) One embodiment of the light intensity control device according to the present invention will be described in detail with reference to Figures 1 to 7.

[0012] Figure 1 is a plan view of the light intensity adjustment device 100. Figure 2 is a rear view of the light intensity adjustment device 100. Figure 3 is an exploded perspective view showing the main parts of the light intensity adjustment device 100. Figure 4 is an exploded perspective view of the light intensity adjustment vanes used as light intensity adjustment members in the light intensity adjustment device. Figure 5 is a diagram showing the interior of the vane chamber, a plan view showing the light intensity adjustment vanes retracted from the aperture. Figure 6 is a diagram showing the interior of the vane chamber similar to Figure 5, a plan view showing the light intensity adjustment vanes entering the aperture. Figure 7 is a diagram showing the interior of the vane chamber of Figure 5, a plan view showing a part of the light intensity adjustment vanes hidden and retracted from the aperture. Figure 8 is a diagram showing the interior of the vane chamber of Figure 6, a plan view showing a part of the light intensity adjustment vanes hidden and entering the aperture.

[0013] In these figures, 1 is the base plate (device base), which includes an opening 1a, a lever rotation shaft 1b, a blade rotation shaft 1c, and blade stoppers 1d and 1e that serve as stoppers. The opening 1a serves as the light passage for the camera and is shaped to retract the lens group inside the camera barrel. The blade stoppers 1d and 1e are designed to contact the light intensity adjustment blades 8, described later, at either or both of the entry and retraction positions, thereby stopping their rotation.

[0014] The sub - floor 2 is a thin plate component arranged between the floor 1 and the light - quantity adjusting blade 8 described later, and is made of a resin sheet member or a metal plate. It has an opening 2a in the central part that opens in a direction orthogonal to the light - passing direction, and serves as the light - passing port of the light - quantity adjusting device 100. Although the sub - floor 2 of this embodiment is separate from the floor 1, it may be integrally formed.

[0015] The magnet 3 is a cylindrical magnetic body, and its outer peripheral surface is magnetized into two poles (N - pole, S - pole).

[0016] The drive lever 4 is configured integrally with the magnet 3. Examples of the integral - forming method include fixing with an adhesive or insert injection molding in the case of resin. The integrally - formed magnet 3 and drive lever 4 are supported by a lever rotation shaft 1b provided on the floor 1 and can perform a rotational motion.

[0017] The stator yoke 5 made of a soft magnetic material is arranged on the outer peripheral curved surface of the magnet 3. The electromagnetic coil unit 6 is configured by winding a coil made of a conducting wire around a bobbin. This electromagnetic coil unit 6 is attached to the floor 1 with the stator yoke 5 inserted.

[0018] The actuator cover 7 is attached to the floor 1 and holds the stator yoke 5 and the drive lever 4.

[0019] As shown in the figure, by assembling these magnet 3, drive lever 4, stator yoke 5, electromagnetic coil unit 6, and actuator cover 7, an electromagnetic actuator serving as the drive source of the light - quantity adjusting device is configured. This electromagnetic actuator drives the light - quantity adjusting blade 8 described later.

[0020] The blade pressing plate 9 has a pressing - plate opening 9a, is arranged opposite to the floor 1, forms a running space for the light - quantity adjusting blade 8 described later, and is a pressing plate that restricts the movement of the light - quantity adjusting blade 8 in the optical - axis direction. The pressing - plate opening 9a becomes the light - passing port of the camera in the same way as the opening 2a of the sub - floor.

[0021] Here, the structure of the light intensity adjustment vane 8 will be described in detail using Figure 4. The light intensity adjustment vane 8 rotates using the electromagnetic actuator, and opens and closes the opening 2a of the sub-ground plate and the retaining plate opening 9a, which become the optical aperture diameter of the light intensity adjustment device 100.

[0022] The light intensity adjustment vane 8 consists of a support vane 10 as a support member, a cover vane 11 as another support member, a light-reducing filter 12, adhesive 13, and a spacer 14.

[0023] The support blade 10 consists of a rotating shaft hole 10a, a hole portion 10b, a blade opening 10c, a diameter outer circumference portion 10d, and stopper contact portions 10e and 10f. The rotating shaft hole 10a fits onto the blade rotating shaft 1c of the base plate, and the hole portion 10b fits onto the drive lever pin 4b.

[0024] The neutral density filter 12 is an optical film made of a sheet material whose surface has been treated to reduce the amount of light transmitted and to suppress light reflection.

[0025] The light-reducing filter 12 is attached to the support vane 10 so as to cover the vane opening 10c and is fixed in place with adhesive 13. The fixing method is not limited to adhesive; mechanical fastening or welding are also possible.

[0026] The light intensity control device 100 in this embodiment is equipped with a light-reducing filter 12, but optical filters that cut out light of specific wavelengths can also be used.

[0027] The cover blade 11 consists of a rotating shaft hole 11a, a hole portion 11b, a blade opening 11c, a diameter outer circumference portion 11d, and stopper contact portions 11e and 11f. The rotating shaft hole 11a fits onto the blade rotating shaft 1c of the base plate, and the hole portion 11b fits onto the drive lever pin 4b.

[0028] By making the support vane 10 and the cover vane 11 parts of the same shape, it becomes possible to use the same mold, resulting in cost advantages in manufacturing.

[0029] The spacer 14 is circular in shape with a hole 14a in the center and is positioned between the support vane 10 and the cover vane 11, with the hole 14a fitting onto the vane rotation axis 1c. The spacer 14 is approximately the same thickness as the light-reducing filter 12, preventing the support vane 10 and the cover vane 11 from approaching each other in the optical axis direction around the rotation axis holes 10a and 11a, thereby preventing deformation of the support vane 10 and the cover vane 11.

[0030] In this embodiment, the light-reducing filter 12 is bonded only to the support vanes 10 and not to the cover vanes 11.

[0031] Both the support vane 10 and the cover vane 11 are engaged with the vane rotation shaft 1c and the drive lever pin 4b of the base plate, and perform the same operation via these shafts. As a result, the light-reducing filter 12, the support vane 10, and the cover vane 11 operate as a single unit.

[0032] Next, the operation of the light intensity adjustment vane 8 will be described in detail using Figures 5 to 8.

[0033] Figure 5 is a diagram showing the interior of the vane chamber, a plan view showing the light intensity adjustment vanes retracted from the opening. Figure 6 is a diagram showing the interior of the vane chamber, similar to Figure 5, a plan view showing the light intensity adjustment vanes entering the aperture. Figure 7 is a plan view of Figure 5 with the cover vanes hidden, and Figure 8 is a plan view of Figure 6 with the cover vanes hidden.

[0034] In the light intensity adjustment device 100 with the above configuration, when the electromagnetic coil unit 6 is energized, the magnet 3 and the drive lever 4 rotate in the direction of energization due to the magnetic action with the stator yoke 5. As a result, the drive lever 4, which is inserted through the hole 10b of the support vane 10, rotates together with the support vane 10, and the light intensity adjustment vane 8 rotates in the direction of rotation around the rotation shaft hole 10a, from the retracted state shown in Figures 5 and 7 to the aperture-reached state shown in Figures 6 and 8.

[0035] When the barrel is rotated to the entry position shown in Figures 6 and 8, the stopper contact portion 10e of the support vane and the stopper contact portion 11e of the cover vane come into contact with the stopper 1d of the base plate, causing the barrel to stop.

[0036] In the aperture entry state shown in Figures 6 and 8, the opening 2a of the sub-ground plate, the blade opening 10c of the support vane, and the blade opening 11c of the cover vane are coaxial, forming a path for light passing through the light intensity adjustment device 100.

[0037] On the other hand, when the electromagnetic coil unit 6 is energized in the reverse direction, the magnet 3 rotates in the reverse direction, and the drive lever 4 also rotates in the reverse direction, causing the light intensity adjustment vane 8 to rotate from the aperture-retracted state shown in Figures 6 and 8 to the retracted state shown in Figures 5 and 7.

[0038] When the vehicle rotates to the retracted position shown in Figures 5 and 7, the stopper contact portion 10f of the support vane and the stopper contact portion 11f of the cover vane come into contact with the stopper 1e of the base plate, causing the vehicle to stop.

[0039] In this embodiment, the distance between the stopper contact portion 10f of the support vane and the adhesive 13 in the aperture-retracted state is longer than the distance between the stopper contact portion 10e of the support vane and the adhesive 13 in the aperture-retracted state. When the aperture stops after the entry operation is complete, the stopper contact portion 10e of the support vane receives an impact force from the stopper 1d of the base plate. The impact force is transmitted to the light-reducing filter 12 via the adhesive 13, but a longer distance between the stopper contact portion 10e of the support vane and the adhesive 13 makes it easier to absorb the impact force, weakening the impact force transmitted to the light-reducing filter 12 and suppressing the occurrence of scratches and foreign matter during durable operation.

[0040] In the aperture retracted state, the distance between the stopper contact portion 10e of the support vane and the adhesive 13 is shorter than the distance in the extended state in order to reduce the outer dimensions of the light intensity adjustment device 100. However, if there are no constraints on the outer dimensions, it is better to increase the distance between the stopper contact portion 10e of the support vane and the adhesive 13 in the aperture retracted state.

[0041] The support blades 10 and cover blades 11 are fitted to the base plate blade rotation axis 1c and the drive lever pin 4b of the drive lever, but the light-reducing filter 12 is not in contact with them.

[0042] Furthermore, in the retracted state shown in Figure 7, the stopper contact portion 10f of the support vane and the stopper contact portion 11f of the cover vane (not shown) are in contact with the stopper 1e of the base plate, while the light-reducing filter 12 is not in contact with the stopper 1e of the base plate.

[0043] In the entry state shown in Figure 8, the stopper contact portion 10e of the support vane and the stopper contact portion 11e of the cover vane (not shown) are in contact with the vane stopper 1d of the base plate, while the light-reducing filter 12 is not in contact with the stopper 1d of the base plate.

[0044] As explained above, since the light-reducing filter 12 does not come into contact with the blade stoppers 1d and 1e, it is not subjected to impact forces on its sides during the reciprocating motion, and therefore no damage occurs. Furthermore, the configuration of this embodiment makes it possible to use optical filters made of materials that are susceptible to impact, such as glass, as the base material.

[0045] In the retracted state of the light intensity adjustment vane 8, as shown in Figures 1 and 2, the light intensity adjustment vane 8 is covered on both sides by the sub-base plate 2 and the vane retaining plate 9, which acts as a cover member. This prevents foreign matter from adhering to the neutral density filter 12 and also prevents the surface from being scratched by such foreign matter. This makes it possible to prevent foreign matter and scratches before the light intensity adjustment device 100 is incorporated into optical equipment such as cameras, and to prevent foreign matter that has unintentionally entered the lens barrel of optical equipment from adhering to it or causing scratches.

[0046] Furthermore, in the light intensity adjustment device 100 incorporated inside the lens barrel, if light is reflected by the light intensity adjustment vane 8 located inside the lens barrel and that reflected light reaches the image sensor, it can cause a decrease in image quality due to ghosting, etc. However, in this embodiment, when the light intensity adjustment vane 8 is retracted, both sides of the vane 8 are covered by the sub-ground plate 2 and the vane retaining plate 9, so it does not reflect light that enters the lens barrel at an oblique angle, making it possible to provide high-quality image data.

[0047] As described above, the dimming filter 12 in this embodiment is bonded to the support vane 10, and since the outer shape of the dimming filter 12 is smaller than that of the support vane 10, it is lighter than a dimming filter that is approximately the same size as the support vane 10. As a result, the dimming filter 12 can be moved with less force, so a small actuator can be used and the light intensity adjustment device can be miniaturized. In addition, because it can be moved with less force, the impact when it collides with the vane stopper can be reduced, and durability can be improved.

[0048] During the aforementioned rotational operation, the light intensity adjustment blade 8 operates while rubbing against the sub-base plate 2 and the blade retaining plate 9, which form the blade travel space, due to material warping and air resistance.

[0049] The light intensity adjustment vane 8 has a support vane 10 on the sub-ground plate 2 side and a cover vane 11 on the vane retaining plate 9 side relative to the dimming filter 12. The outer diameter portions 10d and 11d of the support vane and cover vane cover the entire circumference of the surface that becomes the light passage opening when light enters the opening 1a of the ground plate. Therefore, even if warping occurs due to rotational movement, the outer diameter portions 10d and 11d will contact the sub-ground plate 2 and the vane retaining plate 9 first, and the dimming filter 12 will not come into contact with them, thus preventing any sliding marks.

[0050] On the other hand, since the support vanes 10, cover vanes 11, and light-reducing filter 12 rotate as a single unit, friction does not occur, and friction marks can be prevented from being left on the surface of the light-reducing filter 12.

[0051] As described above, the light intensity adjustment device 100 of the present invention has support vanes 10 and cover vanes 11 arranged on both sides of the light-reducing filter 12 and moves as a single unit, so the occurrence of scratches and foreign matter can be suppressed, and it is possible to provide a light intensity adjustment device that is miniaturized and thin, while suppressing the deterioration of the image quality of optical equipment caused by these scratches and foreign matter.

[0052] (Example 2) A camera, which is an optical instrument equipped with one embodiment of the light intensity adjustment device according to the present invention, will be described with reference to Figures 9 to 10.

[0053] Figures 9 and 10 are external perspective views of a camera 300 equipped with the light intensity adjustment device of the present invention. Figure 9 shows the retracted state of the lens barrel 200 containing the lens group, and Figure 10 shows the extended state of the lens barrel 200.

[0054] The lens barrel 200 of the camera 300 shown in Figures 9 and 10 has a built-in zoom lens, and the focal length and focus are adjusted by moving these lens groups along the optical axis.

[0055] This lens barrel 200 can be freely retracted and extended between the retracted state shown in Figure 9 and the extended state shown in Figure 10.

[0056] This lens barrel 200 has a light intensity adjustment device 100 positioned between the lens groups that make up the photographic lens. In addition to the light intensity adjustment device 100, a lens shutter, aperture mechanism, and image stabilization mechanism may also be located there.

[0057] Furthermore, as shown in Example 1 and Figures 2 and 3, the light intensity adjustment device 100 can be configured to have a main plate opening 1a that is larger than the sub-main plate opening 2a, which is the optical aperture diameter of the camera. When such a light intensity adjustment device is mounted on the camera 300, when the lens is retracted, i.e., when the camera is not in use, or during zoom operation, a portion of the lenses constituting the lens group 200 can be positioned inside the main plate opening 1a of the light intensity adjustment device 100. This makes it possible to shorten the dimension in the optical axis direction, and to make the lens barrel 200 and camera 300 thinner.

[0058] Furthermore, the present invention is not limited to the interchangeable lens type camera described above, but can be broadly applied to optical equipment such as digital cameras and video cameras with integrated lenses.

[0059] The embodiments described above are merely representative examples, and when implementing the present invention, each embodiment may be used. Various transformations and modifications are possible. [Explanation of Symbols]

[0060] 1 Main plate 1a Opening 1b Lever rotation axis 1c Blade rotation axis 1d, 1e Feather stopper 8. Light intensity adjustment blades 9. Blade retaining plate 9a Retaining plate opening 10 support blades 10a Rotating shaft hole 10b Hole 10c Blade opening 10d Outer circumference of the aperture 10e Stopper contact part 10f Stopper contact part 11 Cover blades 11a Rotating shaft hole 11b Hole 11c Blade opening 11d Outer circumference of the bore 11e Stopper contact part 11f Stopper contact part

Claims

1. A base plate with light-passing openings formed therein, A light intensity adjustment device having a light intensity adjustment member that moves forward and backward relative to the light passage opening in accordance with the rotation of a magnet as a driving source, The light intensity adjustment member is configured such that a first support member, an optical film, and a second support member are arranged in the direction of light passage. The light intensity adjustment device is characterized in that the optical film is fixed to at least one of the first support member and the second support member.

2. The facility comprises a cover member positioned relative to the ground plate, The light intensity adjustment member is positioned between the base plate and the cover member. Only the first support member and the second support member of the light intensity adjustment member are in contact with the base plate and the cover member. A light intensity control device characterized by the features of the 1.

3. The light intensity adjustment device 1 is characterized in that the outer shape of the optical film is smaller than the outer shapes of the first support member and the second support member.

4. The base plate is provided with a stopper portion that contacts the light intensity adjustment member at either or both of the stopping positions when the light intensity adjustment member enters or retracts into the light passage opening. Either or both of the first support member or the second support member contact the stopper portion, and the optical filter does not touch the stopper portion. The light intensity adjustment device according to feature 1.

5. The light intensity adjustment device according to claim 1, characterized in that the light intensity adjustment member is a light-reducing filter.

6. An optical instrument characterized by comprising a light intensity adjustment device according to any one of claims 1 to 5.

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