JP2012242632A - Imaging unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging unit that can be reduced in size even if a prism is increased in size to a certain degree in order to prevent occurence of a ghost image.SOLUTION: An imaging unit includes: a circular lens 1; a prism LP1 having a quadrangular incident surface LP1-a opposed to the circular lens in an optical axis direction of the circular lens and an emission surface LP1-b orthogonal to the incident surface; and an imaging element 69 that receives a light bundle emitted from the emission surface of the prism. When viewed in the optical axis direction, an optical axis passes through the center of the incident surface, and a diameter of the circular lens is shorter than a diagonal length of the incident surface.

Description

  The present invention relates to an imaging unit including an imaging optical system and an imaging element.

  In recent years, portable electronic devices mainly for photographing such as digital still cameras and digital video cameras, and portable electronic devices having an incidental photographing function such as camera-equipped mobile phones and portable information terminals have been widely used. In this type of portable electronic device, it is widely performed to incorporate an imaging unit having a configuration in which an imaging element and an imaging optical system for guiding imaging light to the imaging element are housed in a hollow housing. In recent years, as the thickness of portable electronic devices has been reduced, there has been a strong demand for thinning of the imaging unit.

Patent Document 1 is an example of a conventional technique of an imaging unit built in a digital camera. A first lens whose optical axis extends in the thickness direction of the camera body, an incident surface orthogonal to the optical axis of the first lens, A prism having an exit surface orthogonal to the entrance surface, a first lens group comprising a second lens facing the exit surface, and second to fifth lenses arranged in the optical axis direction of the second lens And an image pickup device for receiving the light beam transmitted through the fifth lens group.
When the reflected light of the subject enters the first lens, the reflected light is converted (reflected) by 90 ° in the traveling direction by the prism, and after exiting the exit surface, the reflected light passes through the second lens and the second to fifth lens groups. The light is transmitted and received (imaged) by the imaging surface of the imaging device.

JP 2010-026007 A

In order to reduce the thickness of the imaging unit in Patent Document 1, it is necessary to make the lens diameters of the second lens and the second to fifth lens groups as small as possible within a range in which the effective luminous flux is not vignetted.
When the lens diameters of the second to fifth lenses are reduced, even if the prism is made smaller (even if the area of the emission surface is reduced), the second to fifth lenses are arranged on the second lens group side from the emission surface. An effective light beam having a size (cross-sectional diameter) that is not vignetted by the lens group can be emitted. However, if the prism is made small, a ghost may be generated due to reflection generated by the side surface of the prism, and thus the prism must be made a certain size.
However, in this type of image pickup unit, since the lens diameter of the first lens is larger than the diagonal length of the incident surface of the prism, the lens diameter of the first lens is large. In addition, it is difficult to reduce the size of the imaging unit when viewed in the thickness direction.
If the first lens is made of resin, the imaging unit can be reduced in size by cutting off the outer periphery of the first lens (the portion located on the outer periphery side of the incident surface of the prism) and making the overall shape rectangular. In this case, the manufacturing cost of the first lens is increased. In addition, when the first lens is made of glass, such processing becomes difficult, so it is difficult to reduce the size of the imaging unit by this method (the degree of freedom in selecting the material of the first lens is reduced). .

  An object of the present invention is to provide an imaging unit that can be downsized even when a prism is enlarged to some extent in order to suppress the occurrence of ghosts.

  An imaging unit according to the present invention includes a circular lens, a prism having the circular lens, a rectangular incident surface facing the optical axis direction of the circular lens, and an output surface, and a light beam that has exited the output surface of the prism. And a circular lens having a diameter shorter than the diagonal length of the incident surface.

The exposed portion of the incident surface located on the outer peripheral side of the circular lens when viewed in the optical axis direction may be covered with a light shielding member.
In this case, the light shielding member can be a light shielding mask having an opening into which the circular lens is fitted, for example.

  A housing that houses the imaging element and an image-side lens that guides the light beam emitted from the exit surface to the imaging element side, a lens holding hole that holds the circular lens, and a prism storage space that holds the prism And a holder that is fixed to the housing.

  A mask fixing surface for fixing the light shielding mask to the holder may be formed.

  A first lens group, which is fixed to the holder, and includes a circular lens, a prism, and a lens facing the exit surface in a state of being orthogonal to each other; and the light of the first lens group and the lens provided in the housing. An imaging optical system including a second lens group and a third lens group arranged in the axial direction may be provided.

  According to the present invention, since the diameter of the circular lens is shorter than the diagonal length of the incident surface of the prism, the diameter of the circular lens can be reduced as compared with the prior art. Therefore, the imaging unit can be reduced in size even when the prism is enlarged to some extent in order to suppress the occurrence of ghost.

It is the perspective view seen from the front diagonal upper part of the imaging unit carrying the lens unit of one embodiment of the present invention. It is the disassembled perspective view seen from the front diagonal upper direction of the imaging unit. It is a front view of an image pick-up unit which removed a cover member and a circuit board when an image pick-up optical system is in a wide end position. It is sectional drawing which follows the IV-IV arrow line of FIG. 1 when an imaging optical system exists in a tele end position. It is a front view of the 1st lens group block of the image pick-up unit which removed the cover member and the circuit board, and its peripheral part. It is a disassembled perspective view of the 1st lens group block which abbreviate | omitted the front lens, the front side light shielding mask, and the right side light shielding mask.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, front and rear, left and right, and up and down directions are based on the arrow direction described in the figure.
As shown in FIGS. 1 and 2, the imaging unit 1 includes a first lens group block 3, a main body module 15, a substrate module 65, and a cover member 76 as large components.

The first lens group block 3 includes a holder 4 that is a molded product of synthetic resin. A pair of upper and lower ear pieces 5 having a through hole 6 project from the left end portion of the holder 4. In addition, a prism housing space 7 whose front and right sides are open is formed inside the holder 4, and a front lens holding hole 8 (lens holding hole) whose left side is open at the front opening of the prism housing space 7. A right lens holding hole 9 having a non-circular shape with both upper and lower ends opened is formed in the right side opening of the prism storage space 7 (see FIG. 6). As shown in FIG. 4 and the like, the prism storage space 7 has a rectangular incident surface LP1-a that is long in the vertical direction orthogonal to the front-rear direction and a rectangular output surface that is long in the vertical direction orthogonal to the horizontal direction. A first prism LP1 (prism) including LP1-b is fitted and fixed. A lens L1 (circular lens) whose outer shape is circular and whose optical axis extends in the front-rear direction is fitted and fixed to the front lens holding hole 8 so as to face the incident surface LP1-a in the front-rear direction. .
The diameter of the lens L1 is shorter than the diagonal length of the entrance surface LP1-a of the first prism LP1. When viewed in the front-rear direction, the optical axis of the lens L1 passes through the center of the incident surface LP1-a. Therefore, as shown in FIG. 3, when the first lens group block 3 is viewed from the front, the four corners of the incident surface LP1-a of the first prism LP1 are positioned on the outer peripheral side of the lens L1. However, as shown in FIGS. 2 and 5, a front light-shielding mask 10 (light-shielding member) in which a lens escape hole 11 for avoiding the lens L1 is formed is attached to the front surface (mask fixing surface) of the holder 4 in a fixed state. Since the four corners of the incident surface LP1-a are covered by the four corners of the front light-shielding mask 10, the four corners of the incident surface LP1-a are not exposed forward.

The right lens holding hole 9 of the holder 4 is fitted with a lens unit 12 constituted by joining a lens L2 and a lens L3, both made of resin, (see FIG. 6).
The outer shape of the lens L2 when viewed in the left-right direction is substantially the same as the cross-sectional shape of the right lens holding hole 9. That is, in order to reduce the thickness (front-rear dimension) of the imaging unit 1 (holder 4), the front and rear ends are non-circular. A lens portion L2a having a substantially circular shape and a concave surface on the right side (exit side) is formed at the center of the lens L2. A pair of protrusions L2b are provided on the upper and lower sides of the lens portion L2a. The outer shape of the lens L3 when viewed in the left-right direction is substantially the same as that of the lens L2, and the central portion has the same side shape as the lens portion L2a (the shape when viewed in the left-right direction) and the left side surface ( A lens portion L3a having a convex surface (incident side surface) is formed, and a pair of protrusions L3b are provided on the upper and lower sides of the lens portion L3a.

The lens unit 12 is fitted into the right lens holding hole 9 while the upper and lower protrusions L2b and L3b are positioned in the open portions of the upper and lower ends of the right lens holding hole 9. The right side surface (exit side surface) of the lens L3 is located on the same plane as the right end surface of the holder 4 (the right end surface of the wall forming the right lens holding hole 9), and the lens portion L2a is the first prism. It faces the emission surface LP1-b of LP1 in the left-right direction (the optical axis direction of the lenses L2, L3).
Further, a right light-shielding mask 13 that covers the right side surface of the lens L3 is stuck to the right end surface of the holder 4 in a fixed state (see FIG. 2). However, since the opening 14 is formed in the right light-shielding mask 13, the inner peripheral side portion of the lens portion L3a is exposed to the right side from the outer peripheral edge portion.
The holder 4, the front light shielding mask 10, the lens unit 12, and the right light shielding mask 13 described above are the components of the first lens group block 3. The lens L1, the first prism LP1, the lens L2, and the lens L3 are components of the first lens group LG1.

  The main body module 15 includes a housing 16 made of synthetic resin. A mounting recess 17 is provided in the left end portion of the housing 16, and a storage recess 18 having a substantially rectangular cross section is formed on the front surface of a portion located on the right side of the mounting recess 17. A partition wall 19 is formed between the mounting recess 17 and the storage recess 18, and a communication hole 20 (see FIG. 3) for communicating the mounting recess 17 and the storage recess 18 at the center of the partition wall 19. (See FIG. 4). A positioning portion 22 having a substantially square shape in front view is projected forward from the right end portion of the bottom surface (rear surface) of the storage recess 18. Further, the positioning portion 22 includes three spacers 23a, 23b, and 23c protruding forward, and the front surfaces of the spacers 23a, 23b, and 23c are flat and perpendicular to the front-rear direction (thickness direction of the housing 16). A positioning plane 24 is formed. In addition, a prism recess 25 having openings on the front and left sides is provided in the positioning portion 22. Furthermore, substrate support surfaces 27 that are stepped backward from the front surface of the housing 16 and are orthogonal to the front-rear direction are formed at the front edge portion of the inner peripheral surface of the housing recess 18. Is provided with a locking projection 28 protruding forward. A first engagement recess 30 is formed at the front end of the central portion of the upper surface of the housing 16, which is one step lower than the peripheral portion (downward). The first engagement recess 30 is located on the left side of the first engagement recess 30. A second engaging recess 31 is formed at the same height as 30 and wider than the first engaging recess 30, and an engaging projection 32 projects from the second engaging recess 31. Further, a first engagement recess 30, a second engagement recess 31, and an engagement protrusion 32 having the same configuration are formed on the lower surface of the housing 16. The positional relationship between the first engaging recess 30, the second engaging recess 31, and the engaging protrusion 32 on the lower surface is the same as that on the upper surface, but the first engaging recess 30 and the second engaging recess 31 on the lower surface. The engaging protrusion 32 is displaced to the right as a whole with respect to the upper surface. Further, a pair of upper and lower engaging protrusions 34 project from the right side surface of the housing 16.

  The prism recess 25 is fitted and fixed with a second prism LP2 (exit-side prism) having an entrance surface LP2-a orthogonal to the left-right direction and an exit surface LP2-b orthogonal to the front-rear direction. The entrance surface LP2-a faces the exit surface LP1-b in the left-right direction.

Both the inner ends of the right side wall of the housing 16 and the partition wall 19 are fixed in a state where both ends of the first rod 36 and the second rod 37 which are metal cylindrical members linearly extending in the left-right direction are arranged vertically. .
The first rod 36 is fitted with an insertion hole 40 formed in the upper part of the second group lens frame 39 made of synthetic resin, and the second rod 37 is provided with a rotation stop groove formed in the lower end portion of the second group lens frame 39. 41 is engaged. Since the rotation stop groove 41 engages with the second rod 37 in this way, the rotation of the second group lens frame 39 around the first rod 36 is restricted, so that the second group lens frame 39 has the first rod 36 and the first rod 36. 2 is slidable in the left-right direction along the rod 37. The lens holding hole penetrating the second group lens frame 39 in the left-right direction is composed of two lenses L4 and L5, and the second lens group LG2 facing the exit surface LP1-b and the entrance surface LP2-a in the left-right direction. The (image side lens) is fitted and fixed. Further, a nut holding hole 42 whose left and right ends are open is formed at the upper end portion of the second group lens frame 39, and a driven nut 44 having a female screw hole whose axis extends in the left-right direction is formed in the nut holding hole 42. It is fitted and fixed in a state where the rotation around it is restricted. A first motor M1 made of a stepping motor is fixed to the upper portion of the housing recess 18. The first motor M1 includes a rotary drive shaft M1a that linearly extends to the left, and a male screw groove formed near the tip of the rotary drive shaft M1a is screwed into the female screw groove of the driven nut 44. . Accordingly, when the first motor M1 is operated to rotate the rotational drive shaft M1a forward and backward about its axis, the second group lens frame 39 (lenses L4 and L5) moves along the first rod 36 and the second rod 37. It moves linearly in the left-right direction between the tele end position shown in FIG. 4 and the wide end position shown in FIG.
The second rod 37 is fitted with an insertion hole 48 formed in the lower part of a synthetic resin third group lens frame 47 located on the right side of the second group lens frame 39, and the first rod 36 is fitted with a third group lens. Since the rotation stop groove 49 formed at the upper end of the frame 47 is engaged, the third group lens frame 47 is restricted in rotation along the first rod 36 and the second rod 37 (around the second rod 37). It can slide left and right. A third lens group LG3 (image side lens) which is composed of one lens L6 and concentric with the second lens group LG2 is fitted and fixed in a lens holding hole penetrating the third group lens frame 47 in the left-right direction. A nut holding hole 50 whose left and right ends are open is formed at the lower end of the third group lens frame 47, and the driven nut 44 is restricted from rotating about its own axis (left and right direction) in the nut holding hole 50. It is fitted and fixed in the state. Further, a second motor M2 having the same specification as that of the first motor M1 is fixed to the lower portion of the housing recess 18, and a male screw groove formed near the tip of the rotation drive shaft M2a (same specification as the rotation drive shaft M1a) is driven. The nut 44 is screwed into the female thread groove. Accordingly, when the second motor M2 is operated to rotate the rotational drive shaft M2a forward and backward about its axis, the third group lens frame 47 (third lens group LG3) moves along the first rod 36 and the second rod 37. 4 is moved linearly in the left-right direction between the tele end position shown in FIG. 4 and the wide end position shown in FIG.
The housing 16, the first rod 36, the second rod 37, the second lens group LG2 (second group lens frame 39, driven nut 44), the third lens group LG3 (third group lens frame 47, driven nut 44), described above, The second prism LP2, the first motor M1, and the second motor M2 are components of the main body module 15.

In the first lens group block 3 and the main body module 15, the portion located on the right side of the ear piece 5 of the holder 4 is fitted into the mounting recess 17, and the upper and lower ear pieces 5 and the upper and lower left end surfaces of the housing 16 (attachment) A pair of fixing screws B are inserted into the upper and lower through-holes 6 from the left side with the spacers S sandwiched between the concave portions 17 and the left end surfaces of the protrusions located on the upper and lower sides of the concave portion 17. These parts are integrated by screwing into a female screw hole formed in the left end surface of the housing 16.
When the first lens group block 3 and the main body module 15 are integrated, the right end portion of the holder 4 (the wall forming the right lens holding hole 9) is fitted into the communication hole 20 of the partition wall 19, and the lens unit 12 (lens L2, the optical axis A of the lens L3) coincides with the optical axes of the second lens group LG2 and the third lens group LG3.
The first lens group LG1, the second lens group LG2 (second group lens frame 39, driven nut 44), the third lens group LG3 (third group lens frame 47, driven nut 44), and the second prism LP2 described above are included. The second lens group LG2 (lenses L4 and L5) and the third lens group LG3 (lens L6) advance and retreat along the first rod 36 and the second rod 37, which are components of the imaging optical system (bending optical system). Thus, the imaging optical system performs a zooming operation, and performs a focusing operation by moving the third lens group LG3 back and forth.

The board module 65 includes a circuit board 66 made of a flat plate whose front shape is substantially the same as the housing recess 18 of the housing 16 and orthogonal to the front-rear direction. A printed circuit (not shown) is formed on the rear surface of the circuit board 66, and circular holes 67 are formed at two corners of the circuit board 66.
An imaging element 69 is fixed to the right end portion of the rear surface of the circuit board 66, and a plurality of terminals (not shown) provided on the imaging element 69 are connected to the printed circuit in a fixed state by soldering. An imaging surface (not shown) orthogonal to the front-rear direction is formed on the rear surface of the imaging element 69. Further, the imaging element 69 is provided with a cover glass 70 in a fixed state, which is a flat plate and covers the entire imaging surface on the incident side surface (rear surface in the drawing).
Further, a packing 72 made of an elastic material such as rubber whose front surface and left side surface are open is put on the rear surface (rear end portion) of the image sensor 69. Further, on the rear surface of the packing 72, an exposure hole (through hole) 73 for exposing the entire imaging surface rearward and three through holes for penetrating the spacers 23a, 23b, and 23c are formed. .
The circuit board 66, the image sensor 69, and the packing 72 described above are constituent elements of the board module 65.

The cover member 76, which is a press-formed product of a metal plate, includes a base portion 77 that is a flat plate portion orthogonal to the front-rear direction, a short engagement piece 78 that extends rearward from both upper and lower edges of the base portion 77, and a long length. A dimension engagement piece (elastic engagement piece) 79, and a pair of upper and lower side engagement pieces (elastic engagement pieces) 81 extending in the rear direction from the right edge of the base 77 and extending substantially rearward. Integrated. The base 77 has a substantially rectangular shape that is slightly larger than the circuit board 66, and includes a pressing piece 84, a pressing piece 85, and a pressing piece 86 that are both elastically deformable in the front-rear direction.
The pressing piece 84, the pressing piece 85, and the pressing piece 86 respectively include a pressing protrusion 84a, a pressing protrusion 85a, and a pressing protrusion 86a that protrude from the front to the rear (the pressing piece 84, the pressing piece 85, And the front surface of the portion corresponding to the pressing protrusion 84a, the pressing protrusion 85a, and the pressing protrusion 86a of the pressing piece 86 is recessed), the pressing piece 84, the pressing piece 85, and the pressing piece 86 are in a free state. It is located on the same plane as the other parts of the base 77.
The long engagement piece 79 and the side engagement piece 81 are respectively formed with an engagement hole 80 and an engagement hole 82 each having a square shape.

In order to assemble the board module 65 and the cover member 76 with respect to the main body module 15, first, the circuit board 66 holds the recesses by fitting the two circular holes 67 of the circuit board 66 into the two locking projections 28 of the housing 16. 18 is closed, and the peripheral portion of the rear surface of the circuit board 66 is brought into surface contact with the substrate support surface 27 (the front surface of the circuit board 66 and the front surface of the housing 16 are located on substantially the same plane). Then, the three spacers 23a, 23b, and 23c of the housing 16 pass through the three through holes of the packing 72 forward, and the positioning plane 24 is a flat rear surface of the cover glass 70 of the image sensor 69 (immediately after the image pickup surface). The surface is in contact with the outer peripheral side of the portion positioned, and a gap in the front-rear direction is formed between the cover glass 70 and the second prism LP2 (exit surface LP2-b). Further, the imaging surface of the imaging element 69 faces the exit surface LP2-b of the second prism LP2 in the front-rear direction through the exposure hole 73. Further, the rear surface of the packing 72 comes into contact with the front surface of the positioning portion 22.
Next, the base portion 77 of the cover member 76 is put on the front surface of the housing 16 from the front, and the upper and lower short engagement pieces 78 are engaged with the upper and lower first engagement recesses 30, respectively. By engaging the engagement holes 80 with the upper and lower engagement protrusions 32 and engaging the engagement holes 82 of the upper and lower side engagement pieces 81 with the upper and lower engagement protrusions 34, the cover member 76 is moved. Secure to the housing 16.
When the imaging unit 1 is assembled in this manner, the pressing piece 84, the pressing piece 85, and the pressing protrusion 84a, the pressing protrusion 85a, and the pressing protrusion 86a of the cover piece 76 are on the right side of the front surface of the circuit board 66. From the pressing piece 84, the pressing piece 85, and the pressing piece 86 that are elastically deformed slightly to the front, and are directed rearward to the front surface of the circuit board 66 (through the pressing protrusion 84a, the pressing protrusion 85a, and the pressing protrusion 86a). Since a pressing force (biasing force) is applied, the circuit board 66 and the image sensor 69 are pressed backward. Then, the integrated body of the circuit board 66 and the image sensor 69 is sandwiched from the front and rear by the positioning plane 24 of the three spacers 23a, 23b, and 23c of the housing 16, the pressing protrusion 84a, the pressing protrusion 85a, and the pressing protrusion 86a of the cover member 76. Therefore, the circuit board 66 and the imaging device 69 are accurately positioned in the front-rear direction with respect to the housing 16 and the second prism LP2 by the spacers 23a, 23b, 23c and the pressing protrusions 84a, 85a, 86a.

When the imaging unit 1 is directed to a subject positioned in front, reflected light (photographing light) of the subject passes through the lens L1 and then enters the first prism LP1 through the incident surface LP1-a, and the inner surface of the first prism LP1. Is reflected while the traveling direction is converted by 90 ° toward the exit surface LP1-b. Further, the reflected light that has exited from the exit surface LP1-b passes through the lenses L2 to L6 and then enters the inside of the second prism LP2 from the entrance surface LP2-a. The exit surface LP2-b is incident on the inner surface of the second prism LP2. The traveling direction is reflected by 90.degree. To the side, passes through the exposure hole 73 and the cover glass 70, and is imaged (received) by the imaging surface of the imaging element 69. When the external force or vibration is applied to the image pickup unit 1, the front and back positions of the image pickup element 69 (the image pickup surface thereof) are accurately held at the predetermined design position even when external force or vibration is applied as described above. In this case, the subject image can be picked up by the image pickup element 69 as a focused and unblurred image.
Further, the second lens group LG2 (lenses L4 and L5) and the third lens group LG3 (lens L6) are advanced and retracted along the first rod 36 and the second rod 37 using the first motor M1 and the second motor M2. Thus, if the image pickup optical system is zoomed and focused, the subject image can be picked up in a zoomed and focused state.

In the imaging unit 1 of the present embodiment described above, the diameter of the lens L1 is shorter than the diagonal length of the incident surface of the first prism LP1, and thus the diameter of the lens L1 can be reduced. Therefore, even if the first prism LP1 is enlarged to some extent in order to suppress the occurrence of ghost in the imaging unit 1, the imaging unit 1 is reduced in size (not only the front and rear dimensions but also the left and right dimensions and the vertical dimension are reduced). Is possible.
Further, when the four corners of the incident surface LP1-a of the first prism LP1 are exposed, there is a possibility that intense ghosts may be generated in the imaging unit 1 due to the light beams incident from these four corners. Since the mask 10 is provided so that the four corners of the incident surface LP1-a are not exposed, no intense ghost is generated in the imaging unit 1.

Although the present invention has been described using the present embodiment, the present invention can be implemented with various modifications.
For example, instead of using the front light-shielding mask 10, light-shielding materials (light-shielding members) may be applied or printed at the four corners (portions located on the outer peripheral side of the lens L1) of the incident surface LP1-a of the first prism LP1.
In addition, the shapes of the entrance surface LP1-a and the exit surface LP1-b of the first prism LP1 may be square.
Further, the lens L1 is further reduced in diameter so that when viewed in the front-rear direction, not only the four corners of the incident surface LP1-a but also the other portions are positioned on the outer peripheral side of the lens L1, and these portions are covered with a light shielding member. May be.

Further, the first prism LP1 and the second prism LP2 may be replaced with mirrors.
Furthermore, the prism included in the imaging optical system (bending optical system) may be only the first prism LP1.

DESCRIPTION OF SYMBOLS 1 Imaging unit 3 1st lens group block 4 Holder 5 Ear piece 6 Through-hole 7 Prism storage space 8 Front lens holding hole (lens holding hole)
9 Right lens holding hole 10 Front light shielding mask (light shielding member) (light shielding mask)
DESCRIPTION OF SYMBOLS 11 Lens escape hole 12 Lens unit 13 Right side light shielding mask 14 Circular hole 15 Main body module 16 Housing 17 Mounting recessed part 18 Storage recessed part 19 Bulkhead 20 Communication hole 22 Positioning part 23a 23b 23c Spacer 24 Positioning plane 25 Prism recessed part 27 Substrate support surface 28 Locking projection 30 First engagement recess 31 Second engagement recess 32 34 Engagement projection 36 First rod 37 Second rod 39 Second group lens frame 40 Insertion hole 41 Anti-rotation groove 42 Nut holding hole 44 Driven nut 47 Third group Lens frame 48 Insertion hole 49 Anti-rotation groove 50 Nut holding hole 65 Substrate module 66 Circuit board 67 Circular hole 69 Imaging element 70 Cover glass 72 Packing 73 Exposure hole (through hole)
76 Cover member 77 Base 78 Short engagement piece 79 Long engagement piece (elastic engagement piece)
80 engagement hole 81 side engagement piece (elastic engagement piece)
82 engaging hole 84 85 86 pressing piece 84a 85a 86a pressing projection A optical axis B fixing screw L virtual straight line L1 lens (circular lens)
L2 Lens L2a Lens part L2b Projection part L3 Lens L3a Lens part L3b Projection part L4 Lens L5 Lens L6 Lens LG1 First lens group LG2 Second lens group (image side lens)
LG3 Third lens group (image side lens)
LP1 1st prism (prism)
LP1-a entrance surface LP1-b exit surface LP2 second prism LP2-a entrance surface LP2-b exit surface M1 first motor M1a rotation drive shaft M2 second motor M2a rotation drive shaft S spacer

Claims (6)

A circular lens,
A prism having the circular lens and a rectangular incident surface facing the optical axis direction of the circular lens, and an output surface;
An image sensor for receiving a light beam that has exited the exit surface of the prism;
With
An imaging unit, wherein a diameter of the circular lens is shorter than a diagonal length of the incident surface. The imaging unit according to claim 1,
An imaging unit in which an exposed portion of the incident surface located on the outer peripheral side of the circular lens is covered with a light shielding member when viewed in the optical axis direction. The imaging unit according to claim 2, wherein
An imaging unit, wherein the light shielding member is a light shielding mask having an opening into which the circular lens is fitted. The imaging unit according to claim 1, wherein
A housing that houses the image sensor and an image-side lens that guides the light beam emitted from the exit surface to the image sensor side;
A lens holding hole for holding the circular lens and a prism storage space for holding the prism, and a holder fixed to the housing;
An imaging unit comprising: The imaging unit according to claim 4 dependent on claim 3,
An imaging unit having a mask fixing surface for fixing the light shielding mask to the holder. The imaging unit according to claim 4 or 5,
A first lens group comprising a lens fixed to the holder, the circular lens, a prism, and a lens facing the exit surface in a state of being orthogonal to each other;
A second lens group, and a third lens group, both of which are provided in the housing and are arranged in the optical axis direction of the first lens group and the lens;
An imaging unit comprising an imaging optical system comprising:

Images