JP6900529B2 - Optical equipment - Google Patents

Description

The present invention relates to an optical device such as an interchangeable lens having a lens barrel, and particularly to an optical device suitable for close-up photography (macro photography).

As an interchangeable lens for macro photography as described above, Patent Document 1 has an illumination function in which a plurality of light emitting diodes (LEDs) are arranged at the front end portion around the lens on the most object side in the optical axis direction of the lens barrel. Interchangeable lenses are disclosed. In this interchangeable lens, an accessory mounting portion for mounting an accessory such as an optical filter is provided on the outer side in the radial direction of the front end portion of the lens barrel with respect to the LED. Specifically, a female screw for mounting an optical filter is provided on the inner circumference of a cylindrical portion that protrudes toward an object from the LED on the outer side in the radial direction of the LED. This is because a height in the optical axis direction is required to engage the female screw with the male screw of the optical filter.

JP-A-2007-47192

However, in the interchangeable lens disclosed in Patent Document 1, the illumination light emitted from the LED is blocked by the cylindrical portion or reflected by the inner surface of the optical filter mounted so as to cover the LED inside the cylindrical portion. As a result, the subject may not be illuminated well.

Further, in macro photography, there is a possibility that the cylindrical portion protruding toward the object in the radial direction outside the LED interferes with obstacles existing around the subject, and the front end of the lens barrel cannot be sufficiently brought close to the subject. is there.

The present invention provides an optical device capable of bringing the front end of the lens barrel as close as possible to the subject in macro photography.

An optical device as one aspect of the present invention includes a base lens barrel arranged on the outermost side in the radial direction of the lens barrel and a first lens arranged on the object side in the direction in which the optical axis of the lens barrel extends. It has a movable lens barrel that is held and arranged inside the base lens barrel in the radial direction and can be extended toward the object with respect to the base lens barrel. Then, in a state where the movable lens barrel is extended with respect to the base lens barrel, the apex is a point at the shortest shooting distance or working distance on the optical axis, and the apex is orthogonal to the optical axis through the surface apex on the object side of the first lens. The feature is that the entire movable lens barrel and the entire base lens barrel are located inside the conical surface that passes through the intersection of the surface to be used and the cylindrical surface that extends the outer peripheral surface of the movable lens barrel toward the object. And.

In the optical device of the present invention, the front end of the lens barrel can be sufficiently brought close to the subject in macro photography.

FIG. 5 is a cross-sectional view showing a configuration of an imaging system including an interchangeable lens (extended state) according to an embodiment of the present invention. Sectional drawing of the interchangeable lens (collapsed state) of an Example. The external side view which shows the interchangeable lens (collapsed state and extended state) of an Example. The exploded perspective view of the light emitting part in the interchangeable lens of an Example. The figure which shows the example of the macro photography using the interchangeable lens of an Example.

Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of an imaging system composed of an interchangeable lens 200 as an optical device according to an embodiment of the present invention and a digital camera 500 as an imaging device to which the interchangeable lens 200 is detachably mounted. There is. FIG. 1 shows a cross section of the interchangeable lens 200 in the extended state. In the following description, the left side of the direction in which the optical axis AXL of the interchangeable lens 200 (lens barrel described later) shown in FIG. 1 extends is referred to as an object side or a front side, and the right side is referred to as an image side or a rear side. Further, FIG. 2 shows a cross section of the interchangeable lens 200 in the retracted state. Further, FIGS. 3A and 3B show the appearance of the interchangeable lens 200 in the retracted state and the extended state, respectively.

The digital camera (hereinafter, simply referred to as a camera) 500 includes an image sensor 600 such as a CCD sensor or a CMOS sensor inside. The camera 500 may be a mirrorless digital camera or a single-lens reflex digital camera. It may also be a digital video camera. Further, in the present embodiment, the interchangeable lens type imaging system will be described, but the lens-integrated camera (optical device) is also included in the embodiment of the present invention.

The interchangeable lens 200 has a photographing optical system that forms an optical image (subject image) of the subject. The interchangeable lens 200 of this embodiment is a single focus macro lens capable of macro photography, which is an image taken close to the subject. Further, in the interchangeable lens 200, the lens barrel is formed by the movable lens barrel unit A and the base lens barrel unit B. At the time of shooting, the movable lens barrel unit A is extended with respect to the base lens barrel unit B, which will be described later, and a tapered lens barrel is formed as a whole. On the other hand, during non-shooting, the movable lens barrel unit A is housed (collapsed) with respect to the base lens barrel unit B, and the imaging system can be carried compactly.

The photographing optical system consists of a front end lens (first lens) 1a, an anti-vibration lens 2, a front intermediate lens 1b, an aperture unit 34, a rear intermediate lens 1c, and a focus lens 3 in this order from the object side to the image side. And the rear end lens 4.

Reference numeral 5 denotes a first holding frame for holding the front end lens 1a, the front intermediate lens 1b, and the rear intermediate lens 1c. The anti-vibration lens 2 is provided by an anti-vibration actuator composed of a magnet 8b provided on the shift holding frame 8a for holding the anti-vibration lens 2 and a coil 8d provided on the anti-vibration base frame 8c fixed to the first holding frame 5. Image stabilization is performed by shifting in the direction orthogonal to the optical axis AXL.

Reference numeral 11 denotes a main holding frame that serves as a base for the movable lens barrel unit A. The first holding frame 5, the aperture unit 34, and the front lens barrel 21 surrounding the outer periphery of the first holding frame 5 and the aperture unit 34 are fixed to the main holding frame 11 with screws. The movable lens barrel unit A is composed of the front lens barrel 21, the main holding frame 11, the first holding frame 5, the lenses 1a to 1c, 2, 3 attached to these, the aperture unit 34, and the like. A light emitting portion and an accessory mounting portion, which will be described later, are provided at the front end portion of the front lens barrel 21 which is the most object side.

The front end portion referred to here may be defined as follows. That is, the region from the light emitting surface of the diffuser plate 22 to the apex of the surface of the front end lens 1a on the image sensor 600 side (image side) may be the front end portion. Alternatively, the region from the light emitting surface of the diffusion member 22 to the surface of the light guide 23 on the image sensor 600 side (image side) may be the front end portion.

Reference numeral 10 denotes a focus holding frame for holding the focus lens 3. The focus holding frame 10 is moved in the optical axis direction, which is the direction in which the optical axis AXL extends, by the guide mechanism and the drive mechanism provided in the main holding frame 11 in the movable lens barrel unit A to adjust the focus. The aperture unit 34 adjusts the amount of light that passes through the photographing optical system and reaches the image sensor 600.

Reference numeral 14 denotes a guide cylinder that serves as a base for the base lens barrel unit B, and guide groove portions extending in the optical axis direction are formed at three locations in the circumferential direction thereof. Reference numeral 16 denotes a cam ring, which is rotatably attached to the guide cylinder 14 around the optical axis on the outer circumference of the guide cylinder 14 while being prevented from moving in the optical axis direction by a bayonet coupling. The cam ring 16 is provided with a cam groove portion for extending and retracting the movable lens barrel unit A with respect to the base lens barrel unit B, and a cam follower provided on the main lens barrel 11 guides the cam follower to the cam groove portion. It is engaged with the groove. Therefore, when the cam ring 16 is rotated by the user, the movable lens barrel unit A moves in the optical axis direction. Reference numeral 31 denotes a main board on which a lens driving IC, a CPU, and the like are mounted, which are fixed to the rear end of the guide cylinder 14.

Reference numeral 32 denotes a mount, which is fixed to the guide cylinder 14 with screws. The mount 32 has a contact block (not shown), and the contact block and the main board 31 are electrically connected by a wiring (FPC or the like) (not shown). Further, the mount 32 holds the rear end lens 4. The interchangeable lens 200 is attached to the camera 500 by a bayonet coupling on the mount 32. The interchangeable lens 200 mounted on the camera 500 can communicate with the camera 500 through the contact block and receives power from the camera 500. Using the power supply supplied from the camera 500, the aperture unit 34 of the interchangeable lens 200, the anti-vibration actuator, and the focus actuator described later can be operated, and the light emitting unit can be turned on.

Reference numeral 29 denotes an exterior ring, which has a cylindrical portion that covers the outer periphery of the rear side of the guide cylinder 14, and a flange portion provided on the inner peripheral side thereof is fixed by being sandwiched between the guide cylinder 14 and the mount 32.

Reference numeral 19 denotes a manual focus (MF) ring, which is rotatably supported around the optical axis on the outer periphery of the front side of the guide cylinder 14. When the MF ring 19 is rotated, a sensor (not shown) detects the rotation, and a focus motor (not shown) is driven according to the amount of rotation to move the focus lens 3. As a result, manual focus is performed. The focus lens 3 also moves when the focus motor is driven in response to the AF control signal from the camera 500. As a result, autofocus (AF) is performed.

Reference numeral 35 denotes an operation ring, which is attached to the cam ring 16 so as to cover the outer peripheral surface thereof. Base lens barrel unit B arranged on the outermost side of the lens barrel in the radial direction (direction orthogonal to the optical axis) by the guide cylinder 14, the cam ring 16, the mount 32, the exterior ring 29, the MF ring 19, the operation ring 35, and the like. Is configured. The exterior ring 29, the MF ring 19, and the operation ring 35 are the outermost outer peripheral members arranged on the outermost side in the radial direction in the base lens barrel unit B.

36 shown in FIGS. 3A and 3B is a lighting switch, which is turned on / off by the user in order to turn on / off the LED element 27.

Next, the configuration of the light emitting portion and the accessory mounting portion provided at the front end portion of the front lens barrel 21 will be further described with reference to FIG.

In the light emitting portion, a ring-shaped diffusion plate (diffusion member) 22, two arc-shaped light guides (light guide members) 23, and a ring-shaped cover plate 24 are arranged in order from the object side. Further, an LED element (light source) 27, which is a light source, is arranged at one end in the arc direction of each of the two light guides 23. Each LED element 27 is arranged so that its light emitting surface faces one end surface in the arc direction of the light guide 23. The two LED elements 27 are mounted on the flexible printed wiring board 28 together with the two light guides 23 to form an LED unit.

The diffuser plate 22 is assembled from the front side to the recess 21b provided in the ring-shaped front end portion of the front lens barrel 21, and is adhered to the bottom surface (flat surface) of the recess 21b. Further, the LED unit and the cover plate 24 are assembled to the front end portion of the front lens barrel 21 from the rear side (back side) and fixed to the front end portion by two screws 25. At this time, the two light guides 23 are arranged together with the two LED elements 27 in the arc-shaped holes formed at two locations in the circumferential direction of the recess 21b. As a result, the front surface of the light guide 23 faces the rear surface of the diffuser plate 22. A ring-shaped sheet 26 is arranged on the rear side of the cover plate 24.

Further, the inner peripheral surface of the ring-shaped cylindrical portion 21d forming the radial inner wall of the recess 21b in which the light emitting portion is arranged, that is, the inner peripheral surface of the ring-shaped cylindrical portion 21d in the radial direction from the light emitting portion is a female screw as an accessory mounting portion. A filter screw 21b is formed. A ring-shaped flat surface portion 21d facing the front side is provided at the rear end of the inner peripheral surface of the cylindrical portion 21d. As shown in FIG. 1, a portion of the first holding frame 5 described above that holds the front end lens 1a projects forward from the circular opening formed on the inner circumference of the flat surface portion 21d. As a result, a concave space S facing the inner circumference of the filter screw 21b and opening toward the front side is formed. An optical filter is attached to the front lens barrel 21 so as to cover the front end lens 1a by engaging a male screw formed on the outer peripheral surface of an optical filter (accessory such as a protective filter) (not shown) using this space S. Will be done.

As described above, in this embodiment, the light emitting portion is provided on the outermost side in the radial direction of the front end portion on the most object side of the front lens barrel 21 (movable lens barrel unit A) with respect to the front end lens 1a. Further, a filter screw 21b is provided on the front end portion of the front lens barrel 21 on the radial outside of the front end lens 1a and on the radial inside of the light emitting portion.

Here, the light emitting portion and the filter screw 21b are arranged so as to be aligned in the radial direction with respect to the surface apex AP on the object side of the front end lens 1a. In other words, the filter screw 21b is provided at a position on the image side (opposite to the object side) of the light emitting surface of the diffuser plate 22 of the light emitting portion. In other words, at least a part of the light emitting portion and at least a part of the filter screw 21b overlap in the optical axis direction of the lens barrel. The filter screw 21b is provided on the image side (opposite to the object side) of the light emitting surface of the diffuser plate 22.

That is, the filter screw 21b is not provided at a position protruding forward from the light emitting portion, but the light emitting portion and the filter screw 21b are provided at the same position (region) in the optical axis direction. As a result, the front end lens 1a can be brought closer to the subject as compared with the case where the filter screw is provided on the cylindrical portion protruding forward from the light emitting portion. Further, the illumination light emitted from the light emitting portion is not blocked by the cylindrical portion 21d provided with the filter screw 21b.

The diffuser plate 22 is formed of a milky white acrylic material in order to diffuse the illumination light incident from the LED element 27 via the light guide 23. It is determined in consideration of the light distribution characteristics of the illumination light and the appearance of the light emitting part when viewed from the front side. As the diffuser plate 22, a material other than the milky white acrylic material may be used, or an uneven pattern may be provided on the light emitting surface of the diffuser plate 22.

The flexible printed wiring board 28 on which the LED element 27 is mounted is connected to the main board 31 described above. The LED element 27 is turned on by energizing the LED element 27 from the main board 31 that has received the power supply from the camera 500 via the flexible printed wiring board 28. The light guide 23 is made of a transparent acrylic material, and the rear surface 23a on the flexible printed wiring board 28 side is painted white.

The illumination light emitted from the LED element 27 in the direction of the arrow in FIG. 3 is guided in the arc direction by the light guide 23. At this time, as described above, the illumination light is reflected by the white rear surface 23a of the light guide 23, so that the rear surface 23a becomes a secondary light source, and the reflected illumination light is emitted from the front surface of the light guide 23 to be emitted from the diffuser plate 22. Incident in. With such a configuration, the illumination light is emitted from the entire light guide 23, and further diffused by the diffuser plate 22, so that the illumination light having a uniform light distribution is emitted. As a result, the illumination light is applied to the subject close to the front end lens 1a so as not to cause uneven illumination.

The sheet 26 is made of a soft material such as urethane or rubber, and is fixed to the rear surface of the cover plate 24 with double-sided tape. As shown in FIG. 1, the sheet 26 is sandwiched between the front lens barrel 21, the cover plate 24, and the first holding frame 5 so as to fill a gap between them. As a result, the illumination light leaks into the lens barrel when the LED element 27 emits light, or the inner peripheral surface of the circular opening in the front end lens barrel 21 and the first holding frame 5 inserted into the circular opening. It is possible to prevent dust and water droplets from entering through the gap between the outer peripheral surface and the outer peripheral surface.

Next, the shape of the lens barrel in a state in which the movable lens barrel unit A (front lens barrel 21) is most extended with respect to the base lens barrel unit B will be described with reference to FIG. 3 (b). In the figure, 38 indicates a subject surface (hereinafter, referred to as a closest subject surface) located at the shortest shooting distance from the image pickup surface of the image sensor 600. At this time, the distance from the surface apex AP on the object side of the front end lens 1a to the closest subject surface 38 is defined as the working distance L. Further, the cylindrical outer peripheral surface 21f of the front lens barrel 21 corresponds to the outer peripheral surface of the movable lens barrel unit A.

In FIG. 3B, the point of the shortest shooting distance Lc or the working distance L on the optical axis indicated by AXL (that is, the intersection of the optical axis AXL and the closest subject surface 38) is defined as N. Then, with the point N as the apex, the intersection of the surface P orthogonal to the optical axis AXL through the surface apex AP on the object side of the front end lens 1a and the cylindrical surface extending the outer peripheral surface 21f of the movable lens barrel unit A toward the object side. Let M be a conical surface passing through the line Q. At this time, not only the entire movable lens barrel unit A but also the entire base lens barrel unit B located on the outermost radial direction in the lens barrel is located on the inner side in the radial direction with respect to the conical surface M.

In the interchangeable lens disclosed in Patent Document 1, a cylindrical portion is formed so as to project forward from the position of the intersection line Q which is the outermost circumference of the front end portion of the lens barrel, and a filter screw is formed on the inner circumference of the cylindrical portion. Is formed. That is, the cylindrical portion on which the filter screw is formed projects radially outward from the conical surface M.

On the other hand, in this embodiment, by providing the filter screw 21a radially inside the light emitting portion as described above, it is not necessary to provide a cylindrical portion for forming the filter screw at the position of the line of intersection Q. .. Therefore, it is possible to form a slope 21g having a chamfered corner on the outermost periphery of the front end portion of the front lens barrel 21 so that the front lens barrel 21 has a tapered shape that narrows toward the front end. Then, by adopting a structure in which the movable lens barrel unit A extends out to the base lens barrel unit B on the outer side in the radial direction, the entire lens barrel is tapered from the base lens barrel unit B side toward the front end. It can have a shape.

FIG. 5 shows a state of macro photography by the imaging system of this embodiment. 41 is a subject, and 42 indicates a plane on which the subject 41 is placed. Since the lens barrel has a tapered shape as described above, it is possible to take a picture with the front end lens 1a very close to the subject 41. In particular, since the front lens barrel 21 is provided with the above-mentioned slope 21 g, the front lens barrel 21 is provided with the above-mentioned slope 21 g, so that the front lens barrel 21 is sufficiently close to the subject 41 from the direction in which the front lens barrel 21 is oblique to the plane 41 as shown in the figure. 21 does not interfere with the plane 41 as an obstacle. Therefore, it is possible to shoot from a more free angle with respect to the subject. Further, by providing the slope 21 g, it becomes easy to insert the front end of the lens barrel into a narrow space. Further, by providing the slope 21g, it is possible to prevent the subject from being shaded by the front end of the lens barrel when performing macro photography without turning on the light emitting portion.

Further, in the present embodiment, since the diffuser plate 22 forming the light emitting surface of the light emitting portion is located closest to the object in the lens barrel, the lens barrel blocks the illumination light emitted from the light emitting portion to the subject. It is possible to illuminate the subject efficiently.

Further, in this embodiment, the optical filter attached to the filter screw 21b does not cover the light emitting portion (diffusing plate 22). Therefore, it is possible to prevent the illumination light from the light emitting unit from being reflected on the inner surface of the optical filter and affecting the illumination light, and it is possible to illuminate the subject satisfactorily.

As shown in FIG. 3A, in the retracted state, the front lens barrel 21 includes the light emitting portion of the front end portion thereof and the filter screw 21a, and is contained in the base lens barrel unit B to a position that cannot be seen from the side view. It is stored. As a result, the front end of the lens barrel can be flattened in the retracted state, and the design can be improved.

In the above embodiment, the case where the female screw for mounting the optical filter is provided as the accessory mounting portion has been described, but an accessory mounting portion other than the female screw such as a bayonet claw may be provided. Further, a hood or the like, which is an accessory other than the optical filter, may be attached to the accessory attachment portion.

Further, in the above embodiment, the case where the ring-shaped light emitting portion is formed by using the two LED elements and the two light guides has been described, but the configuration of the light emitting portion is not limited to this. For example, a ring-shaped light emitting portion may be formed by arranging a larger number of LED elements side by side in the circumferential direction, or the LED elements may be arranged only at two positions in the horizontal direction.

Further, in the above embodiment, the configuration of the optical device having the configuration shown in FIG. 3B in the state where the movable lens barrel unit A is most extended from the base lens barrel unit B has been illustrated. It is not limited to. At least in the state where the movable lens barrel unit A is most extended from the base lens barrel unit B, in other words, the configuration shown in FIG. 3B may be sufficient in a state where shooting can be performed at the shortest shooting distance (extended state).

Each of the above-described examples is only a representative example, and various modifications and changes can be made to each of the examples in carrying out the present invention.

1a Front lens A Movable lens barrel unit B Base lens barrel unit 21 Front lens barrel 22 Diffusing plate 23 Light guide 27 LED element 200 Interchangeable lens

Claims (10)

An optical device with a lens barrel
The base lens barrel arranged on the outermost side in the radial direction of the lens barrel,
The first lens arranged on the object side in the direction in which the optical axis of the lens barrel extends is held and arranged inside the base lens barrel in the radial direction, and the object side with respect to the base lens barrel. Has a movable lens barrel that can be extended to
With the movable lens barrel extended with respect to the base lens barrel, the apex is a point at the shortest shooting distance or working distance on the optical axis, and the lens passes through the surface apex on the object side of the first lens. The entire movable lens barrel and the base mirror are inside the radial direction of the conical surface passing through the intersection of the plane orthogonal to the optical axis and the cylindrical surface extending the outer peripheral surface of the movable lens barrel toward the object. An optical device characterized in that the entire cylinder is located. The optical device according to claim 1, wherein a front end portion of the movable lens barrel on the object side is arranged outside the first lens in the radial direction and has a light emitting portion that emits illumination light. The claim is characterized in that, at the front end portion, an accessory mounting portion to which an accessory is detachably mounted is provided outside the first lens in the radial direction and inside the light emitting portion in the radial direction. 2. The optical device according to 2. The optical device according to claim 3, wherein at least a part of the light emitting portion and at least a part of the accessory mounting portion are at the same position in a direction in which the optical axis extends. The optical device according to claim 3 or 4, wherein the accessory mounting portion is provided at a position opposite to the object side of the light emitting surface of the light emitting portion. The optical device according to any one of claims 3 to 5, wherein the accessory mounting portion is formed of a female screw. The light emitting unit
Light source and
A light guide member that guides the light from the light source in the radial direction and the optical axis direction of the lens barrel.
The optical device according to any one of claims 2 to 6, further comprising a diffusing member that diffuses light from the light guide member. The light emitting unit
Light source and
A light guide member that guides the light from the light source in the radial direction and the optical axis direction of the lens barrel.
It has a diffusing member that diffuses light from the light guide member, and has a diffusing member.
The light emitting surface of the light emitting portion is a surface of the diffusion member on the object side.
The optical device according to any one of claims 3 to 6, wherein the accessory mounting portion is provided at a position opposite to the object side of the diffusion member on the object side surface. machine. The optical device according to any one of claims 1 to 8, wherein the movable lens barrel can be extended with respect to the base lens barrel integrally with the first lens. The method according to any one of claims 1 to 9, wherein the outer peripheral surface is provided with a slope so that the size of the movable lens barrel in the radial direction becomes smaller toward the object side. Optical equipment.

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