JP2005107404A - Wide angle imaging optical system, wide angle imaging apparatus equipped with the system, monitoring imaging apparatus, on-vehicle imaging apparatus and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To pick up an image in a wide range having a horizontal viewing angle of about 180° and a vertical viewing angle of about 100° with a simple constitution. <P>SOLUTION: The system is provided with: a catoptric system including 1st and 2nd reflection surfaces for directly reflecting a luminous flux from an object, a 3rd reflection surface 3 for reflecting the luminous flux from the 1st reflection surface 1, and a 4th reflection surface 4 for reflecting the luminous flux from the 2nd reflection surface 2; an image forming optical system 7; an opening part formed in between the 1st reflection surface 1 and the 2nd reflection surface 2 and on which the luminous flux from the object is made incident; and an opening 12a for making the luminous flux from the 3rd and 4th reflection surfaces 3 and 4 on the image forming optical system 7. In descending order from a long conjugate distance side, an optical system to the image forming optical system 7 from the 1st reflection surface 1 through the 3rd reflection surface 3 is regarded as a 1st imaging optical system, and also, in descending order from the long conjugate distance side, an optical system to the image forming optical system 7 from the 2nd reflection surface 2 through the 4th reflection surface 4 is regarded as a 2nd imaging optical system, the 1st imaging optical system and the 2nd imaging optical system share the image forming optical system. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wide-angle imaging optical system suitable for a wide-angle imaging apparatus capable of capturing an image over a wide range, and a wide-angle imaging apparatus, a monitoring imaging apparatus, a vehicle-mounted imaging apparatus, and a projection apparatus including the wide-angle imaging optical system.

  In order to efficiently capture an image of an object over a wide range, various studies and developments have been made to achieve this using a wide-angle imaging device. One example is the development of a wide-angle camera using a fisheye lens.

  Patent Document 1 discloses an all-around panoramic image construction method and apparatus. In Patent Document 1, a mirror is inclined and arranged at a position facing the imaging surface of the imaging apparatus, and the mirror is imaged. A method has been proposed in which a panoramic image is taken by rotating 360 degrees about the optical axis of the apparatus.

  Patent Document 2 discloses an omnidirectional photographing apparatus. In the omnidirectional photographing apparatus, it is necessary to connect the convex mirror and the camera with a transparent cylinder. However, in the omnidirectional photographing apparatus disclosed in Patent Document 2, the light reflected from the inner surface of the cylindrical body is reflected by the convex mirror. In order to prevent the light from being condensed and photographed, a rod-like body for preventing reflection on the inner surface of the cylindrical body is provided at the top of the convex mirror, the tip side of which extends in the camera direction on the axial extension of the convex mirror. .

Further, Patent Document 3 discloses a wide-angle imaging device, and the wide-angle imaging device disclosed in Patent Document 3 has a convex surface shape of approximately ± 90 degrees in the reference optical axis direction around the rotation center axis of the rotationally symmetric body. A range of approximately 180 degrees is photographed with a reflecting mirror having a reflecting surface of.
Japanese Patent Laid-Open No. 11-4373 Japanese Patent No. 3086204 JP 2002-196438 A

  However, a wide-angle imaging optical system using a fisheye lens or the like usually requires many lenses, so that the weight increases and the apparatus becomes large and expensive. Furthermore, such a wide-angle imaging optical system has problems such as the occurrence of chromatic aberration, and can actually be used only for special photography.

  Further, in the all-around panoramic image forming method and apparatus disclosed in Patent Document 1, the apparatus becomes large because the mirror for image pickup is rotated by using the mirror driving rotary motor, and it is long for one panoramic photographing. There was a problem of taking time. Furthermore, since this apparatus captures an image over a range of 360 degrees in all directions, the number of unused pixels increases when, for example, a range of about 180 degrees is sufficient, the necessary image There was a problem that the amount of information was relatively reduced.

  In addition, the omnidirectional imaging device disclosed in Patent Document 2 has a problem in that the structure is complicated and the cost increases because it is necessary to provide a rod-like body for preventing reflection on the inner surface of the cylinder.

  Furthermore, in the wide-angle imaging device disclosed in Patent Document 3, the angle of view in the direction perpendicular to the rotation center axis of the rotationally symmetric body is limited. Therefore, in the configuration with only one reflecting surface, for example, the angle of view is 100 ° or more. Imaging was difficult.

  In addition, a relatively large number of lenses are required to ensure a relatively long back focus that allows optical members such as an optical low-pass filter and a near-infrared cut filter to be disposed and to perform sufficient aberration correction. Therefore, optical design for reducing the number of lenses is a problem.

  The present invention has been made to solve the above-described problems in the prior art, and can capture a wide range of images having a horizontal field of view of about 180 ° and a vertical field of view of about 100 ° with a simple configuration. In addition, an effective area of the image sensor can be used efficiently, and a wide-angle imaging optical system that has a long back focus and good aberration correction and is bright, as well as a wide-angle imaging device, a monitoring imaging device, and an in-vehicle use An object is to provide an imaging device and a projection device.

In order to achieve the above object, the first configuration of the wide-angle imaging optical system according to the present invention includes first and second reflecting surfaces that directly reflect a light beam from an object, and a light beam from the first reflecting surface. A reflective optical system including a third reflecting surface that reflects, and a fourth reflecting surface that reflects a light flux from the second reflecting surface;
An imaging optical system;
An open portion formed between the first reflecting surface and the second reflecting surface, into which a light beam from an object is incident;
An aperture for allowing light beams from the third and fourth reflecting surfaces to enter the imaging optical system,
In order from the long conjugate distance side, the optical system that reaches the image-forming optical system from the first reflecting surface through the third reflecting surface is the first imaging optical system, and the second imaging order from the long conjugate distance side. When the second imaging optical system is an optical system from the reflecting surface through the fourth reflecting surface to the imaging optical system, the first imaging optical system and the second imaging optical system are the imaging optics. It is characterized by sharing the system.

  According to the first configuration of the wide-angle imaging optical system, it is possible to perform imaging over a wide range of about 180 degrees in the horizontal direction and about 100 degrees in the vertical direction. In addition, since the main optical system is formed of reflective surfaces (first to fourth reflective surfaces) that do not generate chromatic aberration, design man-hours and manufacturing restrictions are reduced, and a compact, lightweight and bright wide-angle imaging device can be obtained. It can be provided at low cost.

In the first configuration of the wide-angle imaging optical system of the present invention, when the axis connecting the center of curvature of the first reflecting surface and the center of curvature of the second reflecting surface is a central axis,
The first and second reflecting surfaces are rotationally symmetric with respect to the central axis;
The first reflecting surface and the second reflecting surface are arranged so as to be symmetric with respect to an axis orthogonal to the central axis,
Similarly, the third reflecting surface and the fourth reflecting surface are arranged so as to be symmetric with respect to an axis orthogonal to the central axis, and
It is preferable that the optical axis of the imaging optical system coincides with an axis orthogonal to the central axis. In this case, the first and second reflecting surfaces are preferably aspherical surfaces that are rotationally symmetric with respect to the central axis.

  In the first configuration of the wide-angle imaging optical system of the present invention, the first and second reflecting surfaces are formed over approximately 180 degrees around the central axis, and incident light from an object. It is preferable that the surface is convex when viewed from above.

  In the first configuration of the wide-angle imaging optical system of the present invention, it is preferable that the third and fourth reflecting surfaces are formed in the same element. According to this preferred example, since the number of optical components can be reduced, the apparatus can be reduced in size and weight and the cost can be reduced. In this case, it is preferable that a light shielding portion is formed on the object side surface of the element. According to this preferred example, it is possible to efficiently remove incident light, unnecessary light, and the like from an object that is directly incident on the imaging optical system without passing through the first reflecting surface and the second reflecting surface. .

  In the first configuration of the wide-angle imaging optical system of the present invention, it is preferable that a protective member for protecting the reflective optical system is disposed so as to surround the open portion. According to this preferable example, the reflective optical system can be protected easily and effectively. In this case, it is preferable that a light shielding portion is formed on the protective member. According to this preferable example, the incident angle of the incident light beam is limited within a certain range, and the incident light is incident from an object that is intended to be directly incident on the imaging optical system without passing through the first reflecting surface or the second reflecting surface. Light, unnecessary light, etc. can be removed. In this case, it is preferable that the protective member has an inner surface antireflection structure. According to this preferable example, incident light from an object that is directly incident on the imaging optical system without passing through the first reflecting surface and the second reflecting surface, unnecessary light that causes ghost and flare, etc. Can be removed. In this case, it is preferable that a holding member for holding the first and second reflection surfaces is provided, and the holding member has a light reflection preventing structure. According to this preferred example, when the reflecting optical system is protected by the protective member, the ghost that has conventionally occurred due to the internal reflection of the protective member does not occur due to the light reflection preventing structure by the holding member.

  The first configuration of the wide-angle imaging optical system of the present invention includes a member that holds the imaging optical system and a member that holds the first and second reflecting surfaces, and both members are integrated. It is preferably molded. According to this preferable example, the processing cost in the manufacturing process can be reduced.

A second configuration of the wide-angle imaging optical system according to the present invention includes a refractive optical system including first and second lens groups that refract a light beam from an object;
A reflective optical system including a first reflecting surface that directly reflects a light beam from the first lens group and a second reflecting surface that directly reflects a light beam from the second lens group;
An imaging optical system;
An aperture for allowing light beams from the first and second reflecting surfaces to enter the imaging optical system,
In order from the long conjugate distance side, the optical system from the first lens group through the first reflecting surface to the image forming optical system is the first imaging optical system, and the second optical system in order from the long conjugate distance side. When the second imaging optical system is an optical system from the lens group through the second reflecting surface to the imaging optical system, the first imaging optical system and the second imaging optical system are the imaging optics. It is characterized by sharing the system.

  According to the second configuration of the wide-angle imaging optical system, it is possible to perform imaging over a very wide range, and it is possible to provide a compact, lightweight and bright wide-angle imaging optical system at low cost.

In the second configuration of the wide-angle imaging optical system of the present invention, when the optical axis common to the first and second lens groups is a lens central axis,
The first and second lens groups are rotationally symmetric with respect to the lens central axis;
The first lens group and the second lens group are arranged so as to be symmetric with respect to an axis orthogonal to the lens central axis,
Similarly, the first reflecting surface and the second reflecting surface are arranged so as to be symmetric with respect to an axis orthogonal to the lens central axis, and
It is preferable that the optical axis of the imaging optical system coincides with an axis orthogonal to the lens central axis.

  In the second configuration of the wide-angle imaging optical system of the present invention, it is preferable that the first and second lens groups are arranged over approximately 180 degrees around the lens central axis.

  In the second configuration of the wide-angle imaging optical system of the present invention, it is preferable that the first and second reflecting surfaces are formed in the same element. In this case, it is preferable that a light shielding portion is formed on the object side surface of the element.

  In the first or second configuration of the wide-angle imaging optical system of the present invention, both the imaging magnification of the first imaging optical system and the imaging magnification of the second imaging optical system have the same sign. Is preferred. According to this preferred example, when the image obtained by the first imaging optical system is an erect image, the image obtained by the second imaging optical system is an erect image, and the image obtained by the first imaging optical system is In the case of an inverted image, the image obtained by the second imaging optical system is an inverted image, so that overlapping of images on the image sensor is avoided.

  In the first or second configuration of the wide-angle imaging optical system of the present invention, it is preferable not to form an intermediate image inside the optical system. According to this preferred example, the wide-angle imaging optical system does not become a relay optical system, and the total length of the optical system is reduced, so that the apparatus can be downsized.

  In the first or second configuration of the wide-angle imaging optical system of the present invention, it is preferable that a diaphragm is provided inside the imaging optical system.

  In the first configuration of the wide-angle imaging optical system of the present invention, between the third reflecting surface and the imaging optical system, or between the fourth reflecting surface and the imaging optical system. It is preferable to have an aperture.

  In the second configuration of the wide-angle imaging optical system of the present invention, between the first reflecting surface and the imaging optical system, or between the second reflecting surface and the imaging optical system. It is preferable to have an aperture.

  In the first or second configuration of the wide-angle imaging optical system of the present invention, it is preferable to include a light shielding unit for cutting unnecessary light incident on the imaging optical system. According to this preferred example, the incident from an object that is directly incident on the imaging optical system without passing through the first reflecting surface, the second reflecting surface, or the first lens group or the second lens group. Light, unnecessary light that causes ghost and flare, and the like can be removed.

  In the first or second configuration of the wide-angle imaging optical system of the present invention, it is preferable that the imaging optical system is transparent in an infrared wavelength region including 1 to 10 μm. In the second configuration of the wide-angle imaging optical system of the present invention, it is preferable that the refractive optical system is transparent in an infrared wavelength region including 1 to 10 μm. According to these preferred examples, since the refractive optical system and the imaging optical system transmit light in a wide wavelength range from the visible wavelength range to the infrared wavelength range, a wide wavelength range from the visible wavelength range to the infrared wavelength range. Can be used in the area.

  In the first or second configuration of the wide-angle imaging optical system of the present invention, the imaging optical system includes a first lens as a negative lens and a second lens as a positive lens arranged in order from the object side. And a positive third lens. In the first or second configuration of the wide-angle imaging optical system of the present invention, the imaging optical system includes a first lens as a negative lens and a second lens as a positive lens arranged in order from the object side. And a third lens that is a positive lens and a fourth lens that is a positive lens. According to these preferred examples, it is possible to realize a bright imaging optical system with a small number of lenses and a relatively long back focus and good aberration correction.

  The configuration of the wide-angle imaging device according to the present invention includes the wide-angle imaging optical system according to the present invention and an imaging element that captures an image formed by the imaging optical system. According to the configuration of the wide-angle imaging device, since the wide-angle imaging optical system of the present invention is provided, imaging over a wide range is possible.

  In the configuration of the wide-angle imaging device of the present invention, it is preferable that the imaging element is shared by one imaging element. According to this preferable example, it is possible to realize a reduction in size and weight and a reduction in cost.

  It is preferable that the wide-angle imaging device of the present invention can be attached to an object and the attachment angle can be adjusted. According to this preferable example, the imaging range can be easily changed.

  The wide-angle imaging device of the present invention preferably has a moving object detection function. According to this preferable example, since a moving body can be extracted, it is possible to accurately grasp the surrounding operation state.

  The configuration of the imaging device for monitoring according to the present invention includes the wide-angle imaging device of the present invention. According to the configuration of the monitoring imaging apparatus, since the wide-angle imaging apparatus of the present invention is provided, it is possible to perform imaging over a wide range of horizontal field angles and vertical field angles. In addition, by combining a reflective surface using a material that reflects light and a lens using a material that transmits light, in a wide wavelength range from the visible wavelength range to the infrared wavelength range, in the daytime, A wide range of monitoring can be performed at night.

  The configuration of the in-vehicle imaging device according to the present invention includes the wide-angle imaging device according to the present invention. According to the configuration of the in-vehicle imaging device, since the wide-angle imaging device of the present invention is provided, it is possible to perform imaging over a wide range of horizontal and vertical angles of view, and the captured images are installed in the vehicle. By being configured to project on the in-vehicle monitor, it can be used as a rear view monitor, a front view monitor, a side view monitor, or the like. As a result, it is possible to grasp the surrounding traffic in real time, thereby enabling safer and more comfortable driving.

  The configuration of the projection apparatus according to the present invention includes the wide-angle imaging device according to the present invention. According to the configuration of this projection apparatus, since the wide-angle imaging apparatus of the present invention is provided, a video projector having a very wide field of view can be realized for the observer.

  According to the present invention, imaging over a very wide range is possible. In addition, a small, light and bright wide-angle imaging optical system, a wide-angle imaging device including the same, a monitoring imaging device, an in-vehicle imaging device, and a projection device can be provided at low cost.

  Hereinafter, the present invention will be described more specifically using embodiments.

[First Embodiment]
FIG. 1 is a schematic diagram showing the basic configuration of the wide-angle imaging device according to the first embodiment of the present invention, and is a cross-sectional view cut along a plane including the first horizontal central axis 9. 2 is a view as seen from the direction of arrow A in FIG. 1, and FIG. 3 is a perspective view showing only the main part taken out from FIG.

  As shown in FIGS. 1 to 3, the wide-angle imaging device of the present embodiment includes a reflection optical system, an imaging optical system 7, and an imaging element 8 that captures an image formed by the imaging optical system 7. It has. The reflection optical system includes first and second reflection surfaces 1 and 2 that directly reflect a light beam from an object, a third reflection surface 3 that reflects a light beam from the first reflection surface 1, and a second reflection. The fourth reflecting surface 4 is configured to reflect the light flux from the surface 2. The third reflecting surface 3 and the fourth reflecting surface 4 are formed in one cross prism 14.

  The first horizontal central axis 9 is an axis that connects the center of curvature of the first reflecting surface 1 and the center of curvature of the second reflecting surface 2. The vertical center axis 10 is an axis orthogonal to the first horizontal center axis 9 and is also the optical axis of the imaging optical system 7. 2 is an intersection of the first horizontal central axis 9 and the vertical central axis 10, and the first horizontal central axis 9, the vertical central axis 10 and the second horizontal central axis 9a are points. It passes through c and is mutually orthogonal. The first reflecting surface 1 and the second reflecting surface 2 are arranged symmetrically with respect to the vertical central axis 10 at a predetermined interval on the first horizontal central axis 9. The cross prism 14 is disposed on the first horizontal central axis 9 and at a point c which is an intermediate position between the first reflecting surface 1 and the second reflecting surface 2.

  Between the first reflective surface 1 and the second reflective surface 2, the upper surface serves as a holding member so that the upper surface thereof coincides with a plane including the first horizontal central axis 9 and the second horizontal central axis 9 a. A black housing 12 is disposed, and light beams from the third and fourth reflecting surfaces 3 and 4 are supplied to the imaging optical system 7 in a portion of the black housing 12 where the cross prism 14 is located. An opening 12a for incidence is formed. The opening 12a is provided with a hood 13 for cutting unnecessary light incident on the imaging optical system 7. Moreover, as shown in FIGS. 1-3, between the 1st reflective surface 1 and the 2nd reflective surface 2, it open | releases centering on the point on the 1st horizontal center axis | shaft 9, and from an object An open portion into which the light beam enters is formed. Therefore, the light a and b from the object can enter even if the incident angle θ of the light to the third and fourth reflecting surfaces 3 and 4 shown in FIG. 2 is 0 to 180 degrees. A protective member 11 for protecting the reflective optical system is disposed so as to surround the open portion. The protective member 11 is formed of, for example, a resin material having a thickness of about several mm, for example, an acrylic resin. By arranging the black-coated casing 12 as described above, when the reflective optical system is protected by the protective member 11 made of a resin material, for example, as in the present embodiment, the conventional reflection by the inner surface reflection of the protective member 11 is performed. The generated ghost is prevented from being generated by preventing light reflection by the black housing 12.

  Here, in order from the longest conjugate distance, an optical system from the first reflecting surface 1 to the third reflecting surface 3 and the imaging optical system 7 to the image sensor 8 is referred to as “first imaging optical system”. An optical system that reaches the image sensor 8 through the second reflective surface 2, the fourth reflective surface 4, and the imaging optical system 7 in order from the longer distance side is referred to as a “second imaging optical system”. The center of the cross prism 14 is located at a point c (see FIG. 2) that is the intersection of the first horizontal central axis 9 and the vertical central axis 10 (the optical axis of the imaging optical system 7). The optical axis of the imaging optical system 7 in the system coincides with the optical axis of the imaging optical system 7 in the second imaging optical system. That is, the first imaging optical system and the second imaging optical system share the imaging optical system 7.

  It is desirable that the imaging magnification of the first imaging optical system and the imaging magnification of the second imaging optical system have the same sign. This is also true in the following embodiments.

  It is desirable that the stop is located inside the imaging optical system 7, or between the third reflecting surface 3 and the imaging optical system 7, or between the fourth reflecting surface 4 and the imaging optical system 7.

  The first reflecting surface 1 is a convex surface when viewed from incident light a (light flux incident on the first imaging optical system) from the object, and the second reflecting surface 2 is incident light b (second imaging from the object). It is a convex surface when viewed from a light beam incident on the optical system. Incident light a from an object is reflected by the first reflecting surface 1 and the third reflecting surface 3 in the cross prism 14, and then imaged by the imaging optical system 7 and imaged by the image sensor 8. . The incident light b from the object is reflected by the second reflecting surface 2 and the fourth reflecting surface 4 in the cross prism 14, and then imaged by the imaging optical system 7 and picked up by the image sensor 8. Is done.

  Each of the first and second reflecting surfaces 1 and 2 is an aspheric surface (rotationally symmetric aspheric surface) that is rotationally symmetric with respect to the first horizontal central axis 9. In the present embodiment, the first and second reflecting surfaces 1 and 2 are reflecting surfaces obtained by rotating a hyperbola, respectively, and cover a range of about 180 degrees around the first horizontal central axis 9. Is formed.

  The third and fourth reflecting surfaces 3 and 4 are arranged so as to be symmetric with respect to the vertical central axis 10.

  In FIG. 1, the vertical field angle α in the first imaging optical system is in the range of approximately 0 to 50 degrees when the clockwise direction is positive, and the vertical field angle β in the second imaging optical system is approximately 0 to 0 degrees. It is in the range of −50 degrees. Therefore, in the wide-angle imaging device of the present embodiment, the horizontal field angle is about 180 degrees and the vertical field angle is about 100 degrees. In the present embodiment, the vertical field angle is set to about 100 degrees as described above, but the present invention is not limited to this.

  FIG. 4 shows an image when an object is imaged over a wide range using the wide-angle imaging device shown in FIGS. As shown in FIG. 4, a semi-annular image 42 imaged by the first imaging optical system and a semi-annular image 43 imaged by the second imaging optical system are displayed on the image sensor 8. The annular image 42 and the semi-annular image 43 form one continuous annular image. For this reason, the effective area | region of the image pick-up element 8 can be used efficiently.

  As described above, according to the present embodiment, the main optical system is formed of the reflective surfaces (first to fourth reflective surfaces 1 to 4) that do not generate chromatic aberration. Restrictions are reduced, and a small, light, and bright wide-angle imaging device can be provided at low cost. Further, various aberrations occurring in the optical system can be corrected by making the shape of the reflecting surface of the lens constituting the refractive optical system and the reflecting optical system an aspherical surface. Furthermore, it is possible to perform imaging over a wide range (horizontal field angle: about 180 degrees, vertical field angle: about 100 degrees) while using the image sensor 8 efficiently.

  In the present embodiment, the horizontal field angle and the vertical field angle are defined as shown in FIG. 1, but the horizontal field angle in the present embodiment is defined as the vertical field angle. The vertical field angle of the embodiment may be a horizontal field angle.

  In the present embodiment, the first and second reflecting surfaces 1 and 2 have been described by taking the reflecting surfaces obtained by rotating the hyperbola as an example. 2 may be an ellipse including a circle or a reflecting surface obtained by rotating a parabola. Further, the third and fourth reflecting surfaces 3 and 4 may be curved surfaces, and may be cylindrical surfaces, toric surfaces, or free curved surfaces. Here, the free-form surface is a curved surface having no rotational symmetry axis. This also applies to each of the following embodiments.

  In the wide-angle imaging optical system of the present embodiment, it is desirable not to form an intermediate image inside the optical system. This is also true in the following embodiments.

  In the wide-angle imaging optical system of the present embodiment, it is desirable that the imaging optical system 7 is transparent in the infrared wavelength region including 1 to 10 μm.

[Second Embodiment]
FIG. 5 is a schematic view showing the basic configuration of the wide-angle imaging device according to the second embodiment of the present invention, and is a cross-sectional view cut along a plane including the first horizontal central axis 9. 6 is a view as seen from the direction of arrow B in FIG. As shown in FIGS. 5 and 6, the basic configuration of the wide-angle imaging device of the present embodiment is the same as that of the wide-angle imaging device of the first embodiment shown in FIGS. 14, a right-angle prism 51 is used, and the first and second reflecting surfaces 1 and 2 are formed about 190 degrees around the first horizontal central axis 9 (horizontal image). This is different from the wide-angle imaging device of the first embodiment in that the angle is about 190 degrees.

  As shown in FIG. 5, the incident light a (light beam incident on the first imaging optical system) from the object is reflected by the first reflecting surface 1 and the third reflecting surface 3 in the right-angle prism 51. The image is formed by the image forming optical system 7 and picked up by the image pickup device 8. In addition, incident light b (light beam incident on the second imaging optical system) from the object is reflected by the second reflecting surface 2 and the fourth reflecting surface 4 in the right-angle prism 51, and then the imaging optical system. 7 and imaged by the image sensor 8. The first imaging optical system and the second imaging optical system are decentered from the vertical central axis 10 that is the optical axis of the imaging optical system 7, but various aberrations that occur in the first imaging optical system and the second imaging optical system are The image is corrected accurately by the imaging optical system 7.

  FIG. 7 is a schematic cross-sectional view showing a basic configuration of a wide-angle imaging device in another example of the present embodiment. The configuration shown in FIG. 7 is different from the configuration shown in FIG. 5 in that an eccentric lens 62 is arranged in the imaging optical system 7. The first imaging optical system and the second imaging optical system are decentered from the vertical central axis 10 that is the optical axis of the imaging optical system 7, but by arranging the decentering lens 62, the first imaging optical system and the second imaging optical system are arranged. Various aberrations occurring in the imaging optical system are corrected more accurately.

  FIG. 8 shows an image when an object is imaged over a wide range using the wide-angle imaging device shown in FIGS. As shown in FIG. 8, a substantially semi-annular image 82 imaged by the first imaging optical system and a substantially semi-annular image 83 imaged by the second imaging optical system are displayed on the image sensor 8. The substantially semi-annular image 82 and the substantially semi-annular image 83 form one substantially semi-annular image. For this reason, the effective area | region of the image pick-up element 8 can be used efficiently.

  In the present embodiment, the case where the first and second reflecting surfaces 1 and 2 are formed over the first horizontal central axis 9 over about 190 degrees has been described as an example. Similarly to the first embodiment, it may be formed over approximately 180 degrees around the first horizontal central axis 9. FIG. 9 shows an image when an object is imaged over a wide range using the wide-angle imaging device having this configuration. As shown in FIG. 9, a semi-annular image 92 imaged by the first imaging optical system and a semi-annular image 93 imaged by the second imaging optical system are displayed on the image sensor 8, The annular image 92 and the semi-annular image 93 form a substantially continuous annular image. For this reason, the effective area | region of the image pick-up element 8 can be used efficiently.

  In the present embodiment, the horizontal angle of view is set to about 190 degrees, but is not necessarily limited to this, and may be set to, for example, about 170 degrees.

[Third Embodiment]
FIG. 10 is a schematic diagram showing the basic configuration of the wide-angle imaging device according to the third embodiment of the present invention, and is a cross-sectional view cut along a plane including the first horizontal central axis 9.

  As shown in FIG. 10, the wide-angle imaging device according to the present embodiment includes a refractive optical system, a reflective optical system, an imaging optical system 7, and an imaging element that captures an image formed by the imaging optical system 7. 8 and. The refractive optical system is composed of first and second lens groups 101 and 102 that refract a light beam from an object. The reflective optical system includes a first reflecting surface 5 that directly reflects the light beam from the first lens group 101 and a second reflecting surface 6 that directly reflects the light beam from the second lens group 102. Has been. The first reflecting surface 5 and the second reflecting surface 6 are configured using the surface of the right-angle prism 103.

  The first horizontal central axis 9 is an optical axis common to the first and second lens groups 101 and 102 (lens central axis). The vertical central axis 10 is an axis orthogonal to the first horizontal central axis 9 at the midpoint between the first lens group 101 and the second lens group 102 on the first horizontal central axis 9. It is also the optical axis of the image optical system 7. The center of the right-angle prism 103 is disposed at the intersection of the first horizontal central axis 9 and the vertical central axis 10, and the first reflective surface 5 and the second reflective surface 6 are located on the vertical central axis 10. They are arranged so as to be symmetrical.

  Here, in order from the longest conjugate distance, an optical system from the first lens group 101 to the imaging element 8 through the first reflecting surface 5 and the imaging optical system 7 is a “first imaging optical system”, which is also conjugate. An optical system from the second lens group 102 to the imaging element 8 through the second reflecting surface 6 and the imaging optical system 7 in order from the longest distance side is referred to as a “second imaging optical system”. Since the center of the right-angle prism 103 is located at the intersection of the first horizontal central axis 9 and the vertical central axis 10 (the optical axis of the imaging optical system 7), the light of the imaging optical system 7 in the first imaging optical system. The axis coincides with the optical axis of the imaging optical system 7 in the second imaging optical system. That is, the first imaging optical system and the second imaging optical system share the imaging optical system 7.

  Incident light a from the object (light beam incident on the first imaging optical system) is refracted by the first lens group 101, reflected by the first reflecting surface 5, and then imaged by the imaging optical system 7. The image is picked up by the image pickup device 8. Further, incident light b (light beam incident on the second imaging optical system) from the object is refracted by the second lens group 102, reflected by the second reflecting surface 6, and then connected by the imaging optical system 7. The image is picked up by the image pickup device 8.

  It is desirable that the stop be located inside the imaging optical system 7, or between the first reflecting surface 5 and the imaging optical system 7, or between the second reflecting surface 6 and the imaging optical system 7.

  The first and second lens groups 101 and 102 are spherical surfaces or aspheric surfaces that are rotationally symmetric with respect to the first horizontal central axis 9. The first and second reflecting surfaces 5 and 6 may be curved surfaces, may be cylindrical surfaces or toric surfaces, and may be free curved surfaces.

  FIG. 11 shows an image when an object is imaged over a wide range using the wide-angle imaging device shown in FIG. As shown in FIG. 11, a circular image 112 imaged by the first imaging optical system and a circular image 113 imaged by the second imaging optical system are projected on the image sensor 8, and two circles are displayed. A shaped image is formed.

  FIG. 12 is a schematic diagram showing a basic configuration of a wide-angle imaging device according to another example of the present embodiment, and is a cross-sectional view cut along a plane including the first horizontal central axis 9.

  As shown in FIG. 12, in this configuration, the first and second lens groups 121 and 122 are arranged over a range of about 180 degrees around the first horizontal central axis 9 (horizontal angle of view). Is about 180 degrees). Further, a cross prism 123 is used as an optical component including the first and second reflecting surfaces 5 and 6.

  FIG. 13 shows an image when an object is imaged over a wide range using the wide-angle imaging device shown in FIG. As shown in FIG. 13, a semicircular image 132 imaged by the first imaging optical system and a semicircular image 133 imaged by the second imaging optical system are projected on the image sensor 8, The circular image 132 and the semicircular image 133 form a substantially continuous circular image. For this reason, the effective area | region of the image pick-up element 8 can be used efficiently.

  In the configuration shown in FIG. 12, the horizontal angle of view is set to about 180 degrees, but is not necessarily limited to this, and may be about 170 degrees or about 190 degrees, for example.

  In the wide-angle imaging optical system of the present embodiment, it is desirable that the refractive optical system and the imaging optical system 7 are transparent in the infrared wavelength region including 1 to 10 μm.

[Fourth Embodiment]
FIG. 14 is a schematic diagram showing a basic configuration of a wide-angle imaging device according to the fourth embodiment of the present invention, and is a cross-sectional view cut along a plane including the first horizontal central axis 9. As shown in FIG. 14, the basic configuration of the wide-angle imaging device according to the present embodiment is the same as that of the first embodiment shown in FIGS. The lens barrel that holds the first reflecting surface 1, the second reflecting surface 2, and the member that holds the protective member 11 are integrally molded into a new holding member 141, so that the first This is different from the wide-angle imaging device of the embodiment. By setting it as such a structure, the processing cost in a manufacturing process can be reduced.

  In this embodiment, the case of using the configuration of the wide-angle imaging device of the first embodiment is described as an example, but the configuration of the wide-angle imaging device of other embodiments is used. May be.

[Fifth Embodiment]
FIG. 15 is a schematic view showing a basic configuration of a wide-angle imaging device according to the fifth embodiment of the present invention, and is a cross-sectional view cut along a plane including the first horizontal central axis 9.

  As shown in FIG. 15, the basic configuration of the wide-angle imaging device of the present embodiment is the same as that of the wide-angle imaging device of the first embodiment shown in FIGS. For example, it is different from the wide-angle imaging device of the first embodiment in that a light shielding unit 151 is provided in the vicinity. The light shielding portion 151 is formed by directly blacking a part of the protection member 11. By adopting such a configuration, the incident angle of the incident light beam is limited within a certain range, and it is attempted to directly enter the imaging optical system 7 without passing through the first reflecting surface 1 and the second reflecting surface 2. It is possible to remove incident light, unnecessary light and the like from the object to be performed.

  FIG. 16 is a schematic view showing a basic configuration of a wide-angle imaging device in another example of the present embodiment, and is a cross-sectional view cut along a plane including the first horizontal central axis 9.

  The basic configuration of the wide-angle imaging device shown in FIG. 16 is the same as that of the first embodiment shown in FIGS. 1 to 4, but the third reflecting surface 3 and the fourth reflecting surface 4. Is different from the wide-angle imaging device of the first embodiment in that a cross prism 162 having a light shielding portion 161 provided on the surface on the protective member 11 side is used. The light shielding portion 161 is formed by applying a black coating to the cross prism 162 by a technique such as dipping. With such a configuration, incident light, unnecessary light, and the like from an object that is directly incident on the imaging optical system 7 without passing through the first reflecting surface 1 and the second reflecting surface 2 can be efficiently obtained. Can be removed. If this configuration is used simultaneously with the configuration shown in FIG. 15, unnecessary light or the like can be removed more efficiently.

[Sixth Embodiment]
FIG. 17 is a view showing a light transmission curve of Si ₂ AsTe ₂ which is Si—As—Te based glass. As can be seen from FIG. 17, Si ₂ AsTe ₂ exhibits a high transmittance in the infrared wavelength region (1 to 10 μm). Similarly, germanium or the like is a material exhibiting high transmittance in the infrared wavelength region. On the other hand, for example, a reflective surface formed by coating Al and MgF ₂ on a glass substrate exhibits a high reflectivity of 85% or more in a wide wavelength range from the visible wavelength range to the infrared wavelength range.

From the above, in each of the above embodiments, for example, a reflective surface formed by coating Al and MgF ₂ on a glass substrate, and a refractive optical system formed by a lens using, for example, Si ₂ AsTe ₂ or germanium, and By combining the imaging optical system 7, the reflecting surface reflects light in a wide wavelength range from the visible wavelength range to the infrared wavelength range, and the refractive optical system and the imaging optical system 7 are Since light is transmitted, a wide-angle imaging device that can be used in a wide wavelength range from the visible wavelength range to the infrared wavelength range can be realized.

[Seventh Embodiment]
The wide-angle imaging device in the present embodiment is configured to be attached to an object and to adjust the attachment angle. FIG. 18 and FIG. 19 show an example in which a wide-angle imaging device is used as an in-vehicle imaging device. In the example shown in each of these drawings, the in-vehicle imaging device 191 is attached to the rear portion of the vehicle 193. The basic configuration of the in-vehicle imaging device 191 is the same as the wide-angle imaging device in each of the above embodiments.

  In the example illustrated in FIG. 18, the in-vehicle imaging device 191 has a central axis that is substantially perpendicular to the ground that is the imaging target. On the other hand, in the example illustrated in FIG. 20, the in-vehicle imaging device 191 is inclined with respect to the ground, whose center axis is the imaging target. Thus, by changing the mounting angle of the vehicle-mounted image pickup device 191 with respect to the vehicle 193, the imageable range is changed from the slightly narrow image pickup range 192 (FIG. 18) to the wide image pickup range 202 (FIG. 19). Can do. In addition, if a movable means capable of changing the mounting angle of the in-vehicle imaging device 191 is provided so that the mounting angle of the in-vehicle imaging device 191 can be controlled from the inside of the vehicle 193, an imageable range can be easily obtained. It is possible to change, and it is possible to accurately grasp the surrounding situation.

  In the present embodiment, the case where the wide-angle imaging device is used as an in-vehicle imaging device has been described as an example. However, the present invention is not necessarily limited to this application, and can be used as, for example, a monitoring imaging device. .

[Eighth Embodiment]
FIG. 20 shows an example in which a wide-angle imaging device is used as an in-vehicle imaging device, as in the seventh embodiment. As shown in FIG. 20, the in-vehicle imaging device 211 is attached to the side portion of the vehicle 213. In FIG. 20, 212 indicates an imaging range, and 214 indicates another vehicle. The in-vehicle imaging device 211 has a moving object detection function, and the wide-angle imaging device in each of the above embodiments can be used as the in-vehicle imaging device 211 itself.

  21 and 22 show wide-area images of the in-vehicle imaging device 211. FIG. When another vehicle 214 enters the imaging range 212 of the in-vehicle image pickup device 211, the moving object detection function of the in-vehicle image pickup device 211 operates, and the image of the vehicle 214 becomes a moving object image 222 as shown in FIG. Appears on the wide area image 221. When another vehicle 214 moves, the moving body is automatically tracked, and the image of the vehicle 214 appears on the wide area image 231 as the moving body image 232 as shown in FIG. As described above, since the in-vehicle imaging device 211 has the moving object detection function, an object with movement around the vehicle 213 (in this example, the other vehicle 214) can be extracted and displayed. The attention of the observer (in this example, the driver of the vehicle 213) can be alerted.

  By using the configuration of the present embodiment in combination with the configuration of the seventh embodiment, it is possible to realize a wide-angle imaging system including an imaging range variable function by tilt and a moving object detection function. Imaging can be performed.

[Ninth Embodiment]
FIG. 23 shows an example of a monitoring imaging system including any of the wide-angle imaging devices in the above embodiments. As shown in FIG. 23, a monitoring imaging device 241 is installed in the monitoring space 245, and the monitoring imaging device 241 is connected to the monitor 242 and the image processing device 243 using a cable 244. Then, by developing the captured image into a panoramic image by the image processing device 243, it is possible to perform monitoring over a wide range in real time. Further, by configuring the image processing device 243 to also serve as a recording medium, the captured image can be stored and used as a database. Further, if the monitoring imaging device 241 is configured by a combination of a reflecting surface and a lens as in the sixth embodiment, it can be used in a wide wavelength range from the visible wavelength range to the infrared wavelength range. Therefore, it is possible to perform monitoring over a wide range regardless of daytime or nighttime and to record the state.

[Tenth embodiment]
FIG. 24 shows an example of an in-vehicle imaging system including any of the wide-angle imaging devices in the above embodiments. As shown in FIG. 24, the vehicle 252 has an in-vehicle imaging device 251 attached to the front, rear, side mirror portion, or the like. Then, by configuring the panoramic image captured by the in-vehicle imaging device 251 to be displayed on the in-vehicle monitor 253 installed in the vehicle 252, it can be used as a rear view monitor, a front view monitor, a side view monitor, or the like. . As a result, it is possible to grasp the surrounding traffic in real time, thereby enabling safer and more comfortable driving.

[Eleventh embodiment]
FIG. 25 shows an example of a projection system including any of the wide-angle imaging devices in the above embodiments. As shown in FIG. 25, the projection system in the present embodiment is illuminated with a light source 263, light emitted from the light source 263, and a spatial light modulation element 262 that forms an optical image, and a spatial light modulation element 262. A wide-angle imaging optical system 261 that projects the upper optical image. Here, as the spatial light modulator 262, a liquid crystal panel or the like is used. In FIG. 25, reference numeral 264 denotes a screen serving as a focus plane of an image projected by the wide-angle imaging optical system 261.

  In the projection system of the present embodiment, the optical image formed on the spatial light modulation element 262 illuminated by the light source 263 is enlarged and projected on the screen 264 by the wide-angle imaging optical system 261. Therefore, according to the present embodiment, a video projector having a very wide field of view for the observer 265 can be realized.

[Twelfth embodiment]
FIG. 26 shows an example of a wide conversion lens including the wide-angle imaging optical system in the present invention. The wide conversion lens shown in FIG. 26 is obtained by arranging an imaging device 271 such as a video camera or a camera in place of the imaging optical system 7 and the imaging element 8 in the wide-angle imaging optical system shown in FIG. By using this configuration, it is possible to perform imaging over a wide range at once.

  In this embodiment, the wide-angle imaging optical system of the first embodiment is used, but the wide-angle imaging optical system of other embodiments may be used.

[Thirteenth embodiment]
The wide-angle imaging optical system in the thirteenth embodiment of the present invention will be described below with reference to the drawings and numerical examples. 27 and 28 are schematic cross-sectional views showing wide-angle imaging optical systems corresponding to Numerical Examples 1 and 2 described later, respectively. 27 and 28 and numerical examples 1 and 2 below, i (i = 1, 2, 3,...) Is the surface number, ri is the i-th optical element counted from the object side in the order of light beam progression. , Di is the i-th surface spacing, nd and νd are the refractive index and Abbe number in the d-line, f is the focal length of the optical system, Fno is the brightness, and ω is the imaging range. A2 to A10 and K are the aspherical coefficient and conic constant of the aspherical surface defined by the following (Equation 1), respectively.

但し、上記（数１）中、ｈは項軸からの高さ、Ｚは非球面上の光軸からの高さがｈの点におけるサグ量、Ｒは面の曲率半径をそれぞれ表している。

In the above (Equation 1), h represents the height from the term axis, Z represents the sag amount at the point where the height from the optical axis on the aspheric surface is h, and R represents the radius of curvature of the surface.

  In any of the numerical examples, the first and second reflecting surfaces in the reflecting optical system are convex when viewed from the incident light from the object, and the stop position is between the cross prism 14 and the imaging optical system 7. Is set. A flat plate having a thickness inserted between the lens closest to the image plane and the image sensor 8 corresponds to an optical low-pass filter and a near-infrared cut filter.

(Numerical example 1)
First imaging optical system f = 1.00 Fno = 1.93 ω = 0 to +50 degrees Nori di nd νd
1 -7.646 16.10 MIRROR
2
3 ∞ 2.68 MIRROR
4
5 -2.468 1.34 1.84666 23.8 Joint lens 6 33.284 2.68 1.72916 54.7
7 -4.829 0.13
8 -8.040 2.01 1.72916 54.7
9 -5.925 0.13
10 6.503 2.01 1.52404 56.4
11 162.488 1.34
12 ∞ 4.0 1.51680 64.2
13 ∞

Aspheric coefficient and conic constant 1st surface K = -1.5
Tenth surface A4 = −7.346E-6 A6 = −8.942E-6
A8 = 2.101E-6 A10 = -3.375E-8
K = −0.911
11th surface A4 = 1.284E-4 A6 = -1.764E-5
A8 = 3.047E-6 A10 = −6.566E-8
K = 306.574

Second imaging optical system f = 1.00 Fno = 1.93 ω = -50 to 0 degree Nori di nd νd
1 MIRROR
2 7.646 -16.10
3
4 ∞ 2.68 MIRROR
5 -2.468 1.34 1.84666 23.8 Joint lens 6 33.284 2.68 1.72916 54.7
7 -4.829 0.13
8 -8.040 2.01 1.72916 54.7
9 -5.925 0.13
10 6.503 2.01 1.52404 56.4
11 162.488 1.34
12 ∞ 4.0 1.51680 64.2
13 ∞

Aspheric coefficient and conic constant 1st surface K = -1.5
Tenth surface A4 = −7.346E-6 A6 = −8.942E-6
A8 = 2.101E-6 A10 = -3.375E-8
K = −0.911
11th surface A4 = 1.284E-4 A6 = -1.764E-5
A8 = 3.047E-6 A10 = −6.566E-8
K = 306.574

(Numerical example 2)
First imaging optical system f = 1.00 Fno = 2.01 ω = 0 to +50 degrees Nori di nd νd
1 -7.890 16.61 MIRROR
2
3 ∞ 2.77 MIRROR
4
5 -3.447 1.38 1.84666 23.8 Joint lens 6 88.777 2.77 1.72916 54.7
7 -5.655 0.14
8 7.072 2.77 1.52404 56.4
9 -7.178 1.38
10 ∞ 4.0 1.51680 64.2
11 ∞

Aspheric coefficient and conic constant 1st surface K = -1.5
8th surface A4 = −6.854E-4 A6 = 3.687E-6
A8 = 3.176E-6 A10 = -9.210E-8
K = -1.236
9th surface A4 = −1.266E-4 A6 = −1.082E-4
A8 = 1.096E-5 A10 = -2.614E-7
K = -3.722

Second imaging optical system f = 1.00 Fno = 2.01 ω = -50 to 0 degree Nori di nd νd
1
2 -7.890 -16.61 MIRROR
3
4 ∞ 2.77 MIRROR
5 -3.447 1.38 1.84666 23.8 Joint lens 6 88.777 2.77 1.72916 54.7
7 -5.655 0.14
8 7.072 2.77 1.52404 56.4
9 -7.178 1.38
10 ∞ 4.0 1.51680 64.2
11 ∞

Aspheric coefficient and conic constant 1st surface K = -1.5
8th surface A4 = −6.854E-4 A6 = 3.687E-6
A8 = 3.176E-6 A10 = -9.210E-8
K = -1.236
9th surface A4 = −1.266E-4 A6 = −1.082E-4
A8 = 1.096E-5 A10 = -2.614E-7
K = -3.722

FIG. 29 shows an aberration curve diagram of the optical system in the numerical example 1, and FIG. 30 shows an aberration curve diagram of the optical system in the numerical example 2. In FIG.

  The present invention can be applied to a small, light and bright wide-angle imaging optical system, a wide-angle imaging device including the same, a monitoring imaging device, an in-vehicle imaging device, and a projection device.

It is a schematic sectional drawing which shows the basic composition of the wide angle imaging device in the 1st Embodiment of this invention. It is the figure seen from the arrow A direction of FIG. It is the perspective view which took out and showed only the principal part from FIG. It is the schematic which shows an image when an object is imaged over a wide range using the wide angle imaging device in the 1st Embodiment of this invention. It is a schematic sectional drawing which shows the basic composition of the wide-angle imaging device in the 2nd Embodiment of this invention. It is the figure seen from the arrow B direction of FIG. It is a schematic sectional drawing which shows the basic composition of the wide angle imaging device in the other example of the 2nd Embodiment of this invention. It is the schematic which shows an image when an object is imaged over a wide range using the wide angle imaging device in the 2nd Embodiment of this invention. It is the schematic which shows an image when an object is imaged over a wide range using the wide angle imaging device in the other example of the 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the basic composition of the wide angle imaging device in the 3rd Embodiment of this invention. It is the schematic which shows an image when an object is imaged over a wide range using the wide angle imaging device in the 3rd Embodiment of this invention. It is a schematic sectional drawing which shows the basic composition of the wide angle imaging device in the other example of the 3rd Embodiment of this invention. It is the schematic which shows an image when an object is imaged over a wide range using the wide angle imaging device in the other example of the 3rd Embodiment of this invention. It is a schematic sectional drawing which shows the basic composition of the wide-angle imaging device in the 4th Embodiment of this invention. It is a schematic sectional drawing which shows the basic composition of the wide angle imaging device in the 5th Embodiment of this invention. It is a schematic sectional drawing which shows the basic composition of the wide angle imaging device in the other example of the 5th Embodiment of this invention. A sixth diagram showing an optical transmission curve of Si ₂ Aste ₂ in the embodiment of the present invention. It is the schematic which shows the structure at the time of using the wide angle imaging device in the 7th Embodiment of this invention as a vehicle-mounted imaging device. It is the schematic which shows the other aspect of a structure at the time of using the wide angle imaging device in the 7th Embodiment of this invention as a vehicle-mounted imaging device. It is the schematic which shows the structure at the time of using the wide angle imaging device in the 8th Embodiment of this invention as a vehicle-mounted imaging device. It is the schematic which shows an example of the wide area image of the vehicle-mounted imaging device in the 8th Embodiment of this invention. It is the schematic which shows the other example of the wide area image of the vehicle-mounted imaging device in the 8th Embodiment of this invention. It is a schematic perspective view which shows the imaging system for monitoring in the 9th Embodiment of this invention. It is the schematic which shows the vehicle-mounted imaging system in the 10th Embodiment of this invention. It is the schematic which shows the projection system in the 11th Embodiment of this invention. It is a schematic sectional drawing which shows the wide conversion lens in the 12th Embodiment of this invention. It is a schematic sectional drawing which shows the wide angle imaging optical system corresponding to Numerical example 1 in the 13th Embodiment of this invention. It is a schematic sectional drawing which shows the wide angle imaging optical system corresponding to Numerical example 2 in the 13th Embodiment of this invention. It is an aberration curve figure of the wide angle imaging optical system corresponding to Numerical example 1 in the thirteenth embodiment of the present invention. It is an aberration curve figure of the wide angle imaging optical system corresponding to Numerical Example 2 in the thirteenth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 5 1st reflective surface 2, 6 2nd reflective surface 3 3rd reflective surface 4 4th reflective surface 7 Imaging optical system 8 Imaging element 9 1st horizontal central axis 9a 2nd horizontal central axis DESCRIPTION OF SYMBOLS 10 Vertical center axis 11 Protective member 12 Black housing | casing 12a Opening 13 Hood | hood 14,123,162 Cross prism a Light beam which injects into 1st imaging optical system b Light beam which injects into 2nd imaging optical system c 1st horizontal center axis And a vertical center axis 42 Semi-annular image captured by the first imaging optical system 43 Semi-annular image captured by the second imaging optical system 51, 103 Right angle prism 62 Eccentric lens 82 By the first imaging optical system Captured substantially semi-annular image 83 Approximately semi-annular image captured by the second imaging optical system 92 Semi-annular image captured by the first imaging optical system 93 Captured by the second imaging optical system Toroidal images 101, 121 First lens group 102, 122 Second lens group 112 Circular image 113 imaged by first imaging optical system Circular image 132 imaged by second imaging optical system First imaging optical Semicircular image 133 captured by the system Semicircular image 141 captured by the second imaging optical system Holding member 151, 161 Light-shielding portion 191, 201, 251 In-vehicle imaging device 193, 203, 213, 214, 252 Vehicle 192 Imaging range of in-vehicle imaging device 202 Imaging range of in-vehicle imaging device 212 Imaging range of in-vehicle imaging device 221, 231 Wide area image 222, 232 Moving object image 241 Monitoring imaging device 242 Monitor 243 Image processing device 244 Cable 245 Monitoring space 253 On-vehicle monitor 261 Wide-angle imaging optical system 262 Spatial modulation element 263 Light source 264 Clean 265 observers 271 imaging device

Claims (33)

First and second reflecting surfaces that directly reflect the light beam from the object, a third reflecting surface that reflects the light beam from the first reflecting surface, and a first light beam that reflects the light beam from the second reflecting surface. A reflecting optical system including four reflecting surfaces;
An imaging optical system;
An open portion formed between the first reflecting surface and the second reflecting surface, into which a light beam from an object is incident;
An aperture for allowing light beams from the third and fourth reflecting surfaces to enter the imaging optical system,
In order from the long conjugate distance side, the optical system that reaches the image-forming optical system from the first reflecting surface through the third reflecting surface is the first imaging optical system, and the second imaging order from the long conjugate distance side. When the second imaging optical system is an optical system from the reflecting surface through the fourth reflecting surface to the imaging optical system, the first imaging optical system and the second imaging optical system are the imaging optics. A wide-angle imaging optical system characterized by sharing a system. When the axis connecting the center of curvature of the first reflecting surface and the center of curvature of the second reflecting surface is a central axis,
The first and second reflecting surfaces are rotationally symmetric with respect to the central axis;
The first reflecting surface and the second reflecting surface are arranged so as to be symmetric with respect to an axis orthogonal to the central axis,
Similarly, the third reflecting surface and the fourth reflecting surface are arranged so as to be symmetric with respect to an axis orthogonal to the central axis, and
The wide-angle imaging optical system according to claim 1, wherein an optical axis of the imaging optical system coincides with an axis orthogonal to the central axis. The wide-angle imaging optical system according to claim 2, wherein the first and second reflecting surfaces are aspherical surfaces that are rotationally symmetric with respect to the central axis. The wide angle according to any one of claims 1 to 3, wherein the first and second reflection surfaces are formed over approximately 180 degrees around the central axis and are convex when viewed from incident light from an object. Imaging optical system. The wide-angle imaging optical system according to any one of claims 1 to 4, wherein the third and fourth reflecting surfaces are formed in the same element. The wide-angle imaging optical system according to claim 5, wherein a light-shielding portion is formed on the object-side surface of the element. The wide-angle imaging optical system according to claim 1, wherein a protective member for protecting the reflective optical system is disposed so as to surround the open portion. The wide-angle imaging optical system according to claim 7, wherein a light shielding portion is formed on the protection member. The wide-angle imaging optical system according to claim 7, wherein the protection member has an inner surface antireflection structure. The wide-angle imaging optical system according to claim 7, further comprising a holding member that holds the first and second reflecting surfaces, wherein the holding member has a light reflection preventing structure. The wide-angle imaging optical system according to claim 1, further comprising: a member that holds the imaging optical system; and a member that holds the first and second reflecting surfaces, and both members are integrally molded. . A refractive optical system including first and second lens groups for refracting a light beam from an object;
A reflective optical system including a first reflecting surface that directly reflects a light beam from the first lens group and a second reflecting surface that directly reflects a light beam from the second lens group;
An imaging optical system;
An aperture for allowing light beams from the first and second reflecting surfaces to enter the imaging optical system,
In order from the long conjugate distance side, the optical system from the first lens group through the first reflecting surface to the image forming optical system is the first imaging optical system, and the second optical system in order from the long conjugate distance side. When the second imaging optical system is an optical system from the lens group through the second reflecting surface to the imaging optical system, the first imaging optical system and the second imaging optical system are the imaging optics. A wide-angle imaging optical system characterized by sharing a system. When the optical axis common to the first and second lens groups is the lens central axis,
The first and second lens groups are rotationally symmetric with respect to the lens central axis;
The first lens group and the second lens group are arranged so as to be symmetric with respect to an axis orthogonal to the lens central axis,
Similarly, the first reflecting surface and the second reflecting surface are arranged so as to be symmetric with respect to an axis orthogonal to the lens central axis, and
The wide-angle imaging optical system according to claim 12, wherein an optical axis of the imaging optical system coincides with an axis orthogonal to the lens central axis. The wide-angle imaging optical system according to claim 12 or 13, wherein the first and second lens groups are arranged over approximately 180 degrees around the lens central axis. The wide-angle imaging optical system according to any one of claims 12 to 14, wherein the first and second reflecting surfaces are formed in the same element. The wide-angle imaging optical system according to claim 15, wherein a light-shielding portion is formed on the object-side surface of the element. The wide-angle imaging optical system according to any one of claims 1 to 16, wherein an imaging magnification of the first imaging optical system and an imaging magnification of the second imaging optical system are both the same sign. The wide-angle imaging optical system according to claim 1, wherein an intermediate image is not formed inside the optical system. The wide-angle imaging optical system according to claim 1, further comprising a diaphragm inside the imaging optical system. The wide-angle imaging according to any one of claims 1 to 11, further comprising a stop between the third reflecting surface and the imaging optical system, or between the fourth reflecting surface and the imaging optical system. Optical system. The wide-angle imaging according to any one of claims 12 to 16, further comprising a stop between the first reflecting surface and the imaging optical system, or between the second reflecting surface and the imaging optical system. Optical system. The wide-angle imaging optical system according to claim 1, further comprising a light shielding unit for cutting unnecessary light incident on the imaging optical system. The wide-angle imaging optical system according to claim 1, wherein the imaging optical system is transparent in an infrared wavelength region including 1 to 10 μm. The wide-angle imaging optical system according to claim 12, wherein the refractive optical system is transparent in an infrared wavelength range including 1 to 10 μm. The imaging optical system includes a first lens as a negative lens, a second lens as a positive lens, and a third lens as a positive lens, which are arranged in order from the object side. Wide-angle imaging optical system. The imaging optical system includes a first lens as a negative lens, a second lens as a positive lens, a third lens as a positive lens, and a fourth lens as a positive lens, which are arranged in order from the object side. The wide-angle imaging optical system according to any one of 1 to 16. A wide-angle imaging device comprising: the wide-angle imaging optical system according to any one of claims 1 to 26; and an imaging element that captures an image formed by the imaging optical system. The wide-angle imaging device according to claim 27, wherein the imaging element is shared by one imaging element. The wide-angle imaging device according to claim 27 or 28, wherein the wide-angle imaging device can be attached to an object and the attachment angle can be adjusted. The wide-angle imaging device according to any one of claims 27 to 29, comprising a moving body detection function. A surveillance imaging device comprising the wide-angle imaging device according to any one of claims 27 to 30. An in-vehicle imaging device comprising the wide-angle imaging device according to any one of claims 27 to 30. A projection device comprising the wide-angle imaging device according to any one of claims 27 to 30.

Images