Imaging body and imaging device having the same

An imaging body (1) includes: an attachment/detachment portion (2) to which an imaging optical system (12) is detachably attached; an imaging element (3); and a conversion optical system (4). The conversion optical system (4) is constituted by front side lens systems (4a, 4b) and a rear side lens system (4c). The conversion optical system (4) forms an intermediate image between the attachment/detachment portion (2) and imaging element (3). A shutter (5) is provided near the intermediate image.

BACKGROUND OF THE INVENTION AND RELATED ART

The present invention relates to an optical unit to which an imaging optical system is detachably attached, an imaging unit, an imaging body, and an imaging device.

There is known a camera capable of exchanging an imaging element with another imaging element of a different size according to the purpose (refer to Patent Document 1). This camera has a horizontally-long box-like camera body and a photographing lens for silver salt single-lens reflex camera. As the camera body, a camera body for silver salt single-lens reflex camera is used without modification. As a back lid, one for silver-salt camera and one for digital camera are prepared. When the back lid for digital camera is attached to the camera body, this camera can be used as a digital camera. Further, this camera has a configuration allowing exchange of a CCD substrate and thus different types of digital cameras can be realized by one camera body.Patent Document 1: JP-A-2000-59655

SUMMARY OF THE INVENTION

An imaging body according to a first aspect of the present invention includes: an attachment/detachment portion to which an imaging optical system is detachably attached; an imaging element; and an conversion optical system, wherein the conversion optical system is constituted by a front side lens system and a rear side lens system, the conversion optical system forms an intermediate image between the attachment/detachment portion and the imaging element, and a shutter is provided near the intermediate image.

The shutter is disposed between the attachment/detachment portion and the intermediate image.

The shutter is disposed between the intermediate image and the imaging element.

An imaging device according to the present invention includes the imaging body of the first aspect of the present invention and the imaging optical system.

An imaging body according to a second aspect of the present invention includes: an attachment/detachment portion to which an optical unit is detachably attached; an imaging element; a conversion optical system; and a finder optical system, wherein the conversion optical system is designed to form an intermediate image, the finder optical system has an optical path folding member, the optical path folding member is disposed opposite to the imaging element with respect to the attachment/detachment portion, the direction of a reflecting surface of the optical path folding member is set such that the optical axis of the folded optical path is parallel to the optical axis of the conversion optical system, and another optical system is disposed on the folded optical path.

The another optical system includes another optical path folding member and an eyepiece lens, and the another optical path folding member is disposed on the light incident side of the eyepiece lens so as to reflect light exiting from the eyepiece lens in the direction away from the optical axis of the conversion optical system.

The another optical path folding member includes an image-forming optical system and an eyepiece lens, the image-forming optical path is designed to form an intermediate image, and the eyepiece lens is designed to have its optical axis parallel to the optical axis of the conversion optical system.

An imaging device according to the present invention includes the imaging body of the second aspect of the present invention and the optical unit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Embodiments of the present invention will be described.FIG. 1illustrates an imaging body according to a first embodiment of the present invention. As illustrated inFIG. 1, an imaging body1includes an attachment/detachment portion2, an imaging element3, a conversion optical system4, a shutter5, and a finder optical system6. The attachment/detachment portion2is, e.g., a bayonet ring. An imaging optical system can detachably be attached to the imaging body through the attachment/detachment portion2. Further, a filter7is disposed in front of the imaging element3.

The conversion optical system4is disposed between the attachment/detachment portion2and the imaging element3. An intermediate image I is formed between the attachment/detachment portion2and the imaging element3by the conversion optical system4. A shutter5is disposed near the intermediate image I. In the present embodiment, the shutter5is disposed between the attachment/detachment portion2and the intermediate image I. Alternatively, the shutter5may be disposed between the intermediate image I and the imaging element3.

The conversion optical system4is constituted by front side lens systems4a,4band a rear side lens system4c. The front side lens systems4aand4bhave a positive refractive power as a whole. The rear side lens system4chas a positive refractive power as a whole.

The front side lens systems4aand4bhave a positive refractive power lens4adisposed near the intermediate image I and another positive refractive power lens4b. The lens4a, which is disposed near the intermediate image I, functions as a field lens.

Although the front side lens system4a, front side lens system4b, and the rear side lens system4care each constituted by one lens inFIG. 1, they each may be constituted by a plurality of lenses.

The conversion optical system4is an optical system that forms an intermediate image (primary image). Thus, even when a subject image is enlarged, an aberration-free image can be obtained.

As described above, the imaging body1of the present embodiment includes the conversion optical system4inside thereof. Thus, a large subject image can be formed on the entire light receiving section by the conversion optical system4. As a result, an element having a large light receiving section can be used as the imaging element3. Even in an imaging optical system for an imaging device having a small light receiving section, a large subject image can be formed by means of the conversion optical system4. This provides an advantage that an existing imaging optical system can be used.

Further, in the imaging body1according to the present embodiment, the shutter5is disposed near the intermediate image I (primary image). The intermediate image I is smaller in size than the final image (on the light receiving section of the imaging element3). Thus, the size of the shutter5can be reduced as compared to a case where the shutter5is disposed near the imaging element3.

Further, in the present embodiment, the imaging body1does not include an optical path division means inside thereof, which allows achievement of a reduction in the thickness of the imaging body1.

An imaging body according to a second embodiment is illustrated inFIG. 2. An imaging body1′ according to the present embodiment includes an optical path division means8and a moving mechanism9inside thereof.

The optical path division means8is. e.g., a mirror (quick return mirror). The mirror can be moved between first and second positions by the moving mechanism9. The first position is a position overlapped with lens4′b. The first position is located between the attachment/detachment portion2and the imaging element3. The second position is indicated by a solid line. The second position is a position near a finder optical system6′ which is obtained by rotating the optical path division means8by 45 degrees.

In the present embodiment, the optical path division means8is moved between the first and second positions. The lens4′bis also moved to the first position. Thus, when the optical path division means8is moved to the first position, the lens4′bis moved to a position indicated by a broken line by a moving mechanism (not shown). This avoids a collision between the optical path division means8and the lens4′b.

The conversion optical system4′ is disposed between the attachment/detachment portion2and the imaging element3. An intermediate image I is formed between the attachment/detachment portion2and the imaging element3by the conversion optical system4′. The shutter5is disposed near the intermediate image I. In the present embodiment, the shutter5is disposed between the attachment/detachment portion2and the intermediate image I. Alternatively, the shutter5may be disposed between the intermediate image I and the imaging element3.

As described above, the imaging body1′ of the present embodiment includes the conversion optical system4′ inside thereof. Thus, a large subject image can be formed on the entire light receiving section by the conversion optical system4′. As a result, an element having a large light receiving section can be used as the imaging element3. Even in an imaging optical system for an imaging device having a small light receiving section, a large subject image can be formed by means of the conversion optical system4′. This provides an advantage that an existing imaging optical system can be used.

Further, in the imaging body1′ according to the present embodiment, the shutter5is disposed near the intermediate image I (primary image). The intermediate image I is smaller in size than the final image (on the light receiving section of the imaging element3). Thus, the size of the shutter5can be reduced as compared to a case where the shutter5is disposed near the imaging element3.

It appears inFIG. 2that an area of the portion where the optical path division means8crosses the optical path is small in a state where the optical path division means8is located at the first position. Actually, however, the optical path division means8has an area sufficient to reflect all light beams even in this state.

Next, as a third embodiment, an imaging device is illustrated inFIG. 3. An imaging device20according to the present embodiment includes the imaging body1and an optical unit21. As illustrated inFIG. 3, the optical unit21includes an imaging optical system22, the optical path division means8, and the moving mechanism9. The optical unit21is connected to the imaging body1through the attachment/detachment portion2and thereby a subject image is formed on the imaging element3through the imaging optical system22and the conversion optical system4.

Another imaging device is illustrated inFIG. 4as a fourth embodiment. An imaging device20′ according to the present embodiment includes the imaging body1′ and an optical unit21′. As illustrated inFIG. 4, the optical init21′ includes an imaging optical system22′. The optical unit21′ is connected to the imaging body1′ through the attachment/detachment portion2and thereby a subject image is formed on the imaging element3through the imaging optical system22′ and the conversion optical system4′.

Other embodiments of the present invention will be described below. An imaging body according to a fifth embodiment is illustrated inFIG. 5. As illustrated inFIG. 5, the imaging body31includes the attachment/detachment portion2, the imaging element3, the conversion optical system4, and a finder optical system16. The attachment/detachment portion2is, e.g., a bayonet ring. An optical unit can detachably be attached to the imaging body through the attachment/detachment portion2. Further, in the present embodiment, the filter7is disposed in front of the imaging element3.

The conversion optical system4is disposed between the attachment/detachment portion2and the imaging element3. An intermediate image I is formed between the attachment/detachment portion2and the imaging element3by the conversion optical system4.

The conversion optical system4is constituted by the front side lens systems4a,4band rear side lens system4c. The front side lens systems4aand4bhave a positive refractive power as a whole. The rear side lens system4chas a positive refractive power as a whole.

The front side lens systems4aand4bhave a positive refractive power lens4adisposed near the intermediate image I and another positive refractive power lens4b. The lens4a, which is disposed near the intermediate image I, functions as a field lens.

Although the front side lens system4a, front side lens system4b, and rear side lens system4care each constituted by one lens inFIG. 5, they each may be constituted by a plurality of lenses.

The conversion optical system4is an optical system that forms an intermediate image. Thus, even when a subject image is enlarged, an aberration-free image can be obtained.

The finder optical system16includes an optical path folding member10. In the present embodiment, the optical path folding member10is a prism. Alternatively, the optical path folding member10is a mirror. The direction of a reflecting surface of the optical path folding member10is set such that an optical axis L2of the folded optical path is parallel to an optical axis L1of the conversion optical system4. However, the optical paths L1and L2need not be completely parallel to each other. On the folded optical path, an optical system other than the finder optical system16is disposed.

An imaging body31of the present embodiment does not include the optical path division means inside thereof. The optical path division means is provided in an optical unit to be described later. Thus, when the optical unit is attached to the imaging body31, the optical path division means is located on the front side (opposite side of the imaging element3with respect to the attachment/detachment portion2) relative to the attachment/detachment portion2. Thus, the optical path folding member10is disposed opposite to the imaging element3with respect to the attachment/detachment portion2. With this arrangement, light reflected by the optical path division means, i.e., light from a subject can be guided to the finder optical system16.

The finder optical system16includes two types: one that does not form an intermediate image (secondary intermediate image) therein; and one that forms the secondary intermediate image therein. In the present embodiment, the finder optical system16is an optical system that does not form the second intermediate image. Thus, the finder optical system16includes, as another optical system, another optical path folding member11and an eyepiece lens12.

Light from a subject travels to the finder optical system16through the optical unit and forms an intermediate image (primary intermediate image I′). The light then enters the optical path folding member10. The optical path folding member10is a pentaprism. The light passing through an incident surface10aof the pentaprism is reflected by a first reflecting surface10band travels to a second reflecting surface10c. The direction of second reflecting surface10cis set such that the optical axis L2of the folded optical path is parallel to the optical axis L1of the conversion optical system4. Accordingly, the light (on-axis main beam) reflected by the second reflecting surface10cbecomes parallel to the optical axis L1of the conversion optical system4, and the resultant light passes through an exit surface10d.

The light exiting from the exit surface10dthen enters the another optical path folding member11. The another optical path folding member11is a mirror. The another optical path folding member11is disposed on the light incident side of the eyepiece lens12. The light entering the another optical path folding member11is reflected to the eyepiece lens12. The eyepiece lens12is disposed opposite to the conversion optical system4with respect to the optical axis L2. That is, the another optical path folding member11(reflecting surface thereof) is disposed so as to reflect the light exiting from the eyepiece lens12in the direction away from the optical axis L1of the conversion optical system4.

As described above, the imaging body31of the present embodiment includes the conversion optical system4inside thereof. Thus, a large subject image can be formed on the entire light receiving section by the conversion optical system4. As a result, an element having a large light receiving section can be used as the imaging element3. Even in an imaging optical system for an imaging device having a small light receiving section, a large subject image can be formed by means of the conversion optical system4. This provides an advantage that an existing imaging optical system can be used. Further, the imaging body31of the present embodiment does not include the optical path division means inside thereof, which allows achievement of a reduction in the thickness of the imaging body1.

In the present embodiment, the conversion optical system4is provided in the imaging body31, so that the thickness increases in the optical axis direction. However, the finder optical system16in the present embodiment is designed to reflect the light exiting from the eyepiece lens in the direction away from the optical axis of the conversion optical system, so that the finder optical system16providing easy observation can be obtained.

Further, the finder optical system16of the present embodiment does not form an intermediate image (secondary intermediate image), so that the finder optical system16is constituted by a small number of parts (two optical path folding members10,11and eyepiece lens12), thereby simplifying the configuration of the finder optical system16.

Further, in the finder optical system16of the present embodiment, the distance between the primary intermediate image I′ and eye point is smaller than in the finder optical system that forms the intermediate image (secondary intermediate image). On the other hand, however, the light exiting from the eyepiece lens12is guided in the direction away from the optical axis L1of the conversion optical system4, allowing a photographer to confirm a subject from above the imaging body31through a finder. Thus, the small distance between the primary intermediate image I′ and eye point does not adversely affect the confirmation of a subject.

A sixth embodiment of the present invention will be described. An imaging body according to the sixth embodiment is illustrated inFIG. 6. InFIG. 6, the same reference numerals as those inFIG. 5denote the same parts as those inFIG. 1, and the descriptions thereof will be omitted here. An imaging body31′ of the present embodiment includes a finder optical system16′.

The finder optical system16′ in the present embodiment forms a secondary intermediate image. Thus, the finder optical system16′ includes, as another optical system, an image-forming optical system13and the eyepiece lens12. The image-forming optical system13is constituted by a first lens13aand a second lens13b.

Light from a subject travels to the finder optical system16′ through the optical unit and forms a primary intermediate image I′. The first lens13ais disposed near the primary intermediate image I′. The light passing through the first lens13aenters an optical path folding member10′. The optical path folding member10′ is a mirror. The light that has entered the optical path folding member10′ is reflected by the reflecting surface of the optical path folding member10′.

The direction of the reflecting surface of the optical path folding member10′ is set such that an optical axis L2of the folded optical path is parallel to an optical axis L1of the conversion optical system4. Accordingly, the light (on-axis main beam) reflected by the optical path folding member10′ becomes parallel to the optical axis L1of the conversion optical system4, and the resultant light travels to the second lens13b. The light then enters the second lens13band forms a secondary intermediate image I″. The light from the secondary intermediate image I″ enters the eyepiece lens12. The eyepiece lens12is designed to have its optical axis parallel to the optical axis L1of the conversion optical system4. On the folded optical path, the above-mentioned another optical system is disposed.

Since the secondary intermediate image I″ is formed in the finder optical system16′ as described above, the distance between the primary intermediate image I′ and eye point is larger than in the finder optical system16′ that forms the secondary intermediate image I″. As described above, in the present embodiment, the conversion optical system4is provided in the imaging body31′, so that the thickness increases in the optical axis direction. However, the finder optical system16′ in the present embodiment forms the secondary intermediate image I″, so that the eyepiece lens12can be located near the rear surface of the imaging body31′, so that the finder optical system16′ providing easy observation can be obtained. Further, the optical path folding member10′, the second lens13b, and eyepiece lens12can be arranged in series, simplifying the optical path of the finder optical system16′.

Next, as a seventh embodiment, an imaging device is illustrated inFIG. 7. An imaging device40according to the present embodiment includes the imaging body31and optical unit21. As illustrated inFIG. 7, the optical unit21includes the imaging optical system22, an optical path division means23, and a driving mechanism24. The optical unit21is connected to the imaging body31through the attachment/detachment portion2and thereby a subject image is formed on the imaging element3through the imaging optical system22and the conversion optical system4.

As an eighth embodiment, another imaging device is illustrated inFIG. 8. An imaging device40′ according to the present embodiment includes the imaging body31′ and the optical unit21.

According to the above embodiments, an imaging body capable of using imaging elements different in the size of a light receiving section and capable of reducing the size of a shutter can be obtained while its thin-shape maintained. Further, a finder optical system providing easy observation can be obtained. In addition, an imaging device including this imaging body can be obtained.

The present invention may be variously modified without departing the scope thereof.