JP2006267391A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus of which the thickness can be reduced without deteriorating optical performance. <P>SOLUTION: The imaging apparatus 100 is constituted of an imaging device 50 and a plurality of lenses including non-circular lenses 1, 3, 7. The imaging device 50 has a rectangular light receiving surface 50a. The imaging device 50 is an element for converting an optical image formed on the light receiving surface 50a into an electric signal. The image of an object is formed on the light receiving surface 50a through the plurality of lenses. Each of the non-circular lenses 1, 3, 7 has a shape obtained by removing a portion which does not contribute image formation on the light receiving surface 50a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging device including an imaging element and a plurality of lenses, and can be applied to, for example, an imaging device that can be mounted on a thin portable terminal.

  2. Description of the Related Art Conventionally, there has been an imaging apparatus that includes an imaging element such as a CCD (Charge Coupled Device) and a plurality of lenses. In recent years, the imaging apparatus has been mounted on a mobile terminal such as a mobile phone.

  Conventionally, the imaging device has been applied to a digital still camera. However, an imaging device having a function of bending an optical axis in a vertical direction is mounted on the digital still camera because of a demand for thinness. Patent Documents 1, 2, and 3 exist as imaging devices having the bending function.

  By the way, for example, when mounting an imaging device on a mobile phone, the following imaging device is desirable.

  In other words, it is desirable that the imaging apparatus has a wider angle of view at the zoom wide end (a state in which the widest range is visible (wide angle end)). In addition, as the configuration of the optical system, image side telecentric (in the present specification, it means that the light incident angle on the imaging surface is substantially constant) in order to suppress a decrease in marginal light intensity. It is desirable that

  Patent Document 1, Patent Document 2, and Patent Document 3 all employ a retrofocus configuration to achieve a wide field angle at the zoom wide end and image-side telecentricity over the entire zoom range. Further, in the first lens group and the fourth lens group, the enlargement of each lens is suppressed by narrowing the luminous flux.

JP 2004-37927 A JP 2004-56362 A JP 2003-222946 A

  By the way, in the imaging apparatus according to Patent Documents 1 to 3, the thickness of the imaging apparatus (thickness in the direction perpendicular to the normal direction of the imaging element) is disposed on the lens (particularly on the normal axis of the imaging element). This depends on the size of the lens other than the lens group having a diaphragm function. Therefore, the smaller the size of the lens, the thinner the imaging device.

  However, when realizing image-side telecentricity, the diameter of the circular lens arranged closest to the image sensor must be at least larger than the diagonal line of the image sensor, and there is a limit to reducing the thickness of the image sensor. .

  In addition, since the retrofocus configuration is used, the diameter of the circular lens belonging to the lens group arranged closest to the subject is increased when the wide angle of view is set. The enlargement of the circular lens diameter has been a factor that hinders thinning of the imaging device.

  In other words, a lens group having an optical axis bending function is generally composed of a prism lens and lenses disposed before and after the prism lens.

  Since the lens group having the optical axis bending function is configured as described above, downsizing of the lens group is limited in order to prevent interference (physical contact) between the lenses. Such a limitation on the size reduction of the lens group having the optical axis bending function has been a factor that hinders the thickness reduction of the imaging device.

  In addition, the thinner the imaging device, the thinner the digital still camera on which the imaging device is mounted.

  Therefore, an object of the present invention is to provide an imaging device that can be thinned without degrading optical performance.

  In order to achieve the above object, an imaging device according to claim 1 of the present invention has a rectangular light receiving surface, and converts an optical image formed on the light receiving surface into an electrical signal; A plurality of lenses that form an image of a subject on the light receiving surface, and at least one of the plurality of lenses is a portion that does not contribute to image formation on the light receiving surface from a circular lens, It is configured by a non-circular lens having a shape obtained by removing at least one predetermined peripheral portion.

  An imaging apparatus according to claim 1 of the present invention has a rectangular light receiving surface, converts an optical image formed on the light receiving surface into an electric signal, and forms an image of a subject on the light receiving surface. A plurality of lenses, wherein at least one of the plurality of lenses has a circular lens with at least one predetermined peripheral portion removed from a portion that does not contribute to image formation on the light receiving surface. Since it is configured by a non-circular lens having a shape, the surface area of the lens can be further reduced. As a result, the image pickup apparatus can be reduced in size and thickness.

  Conventionally, each lens disposed in the imaging apparatus has a circular shape. However, the inventor has noticed that the circular lens has a portion that does not contribute to image formation on the light receiving surface of the image sensor.

  When a non-circular lens having a shape in which at least one predetermined peripheral portion is removed from a circular lens that does not contribute to image formation on the light receiving surface is employed in the imaging device, the imaging device is made thinner. When possible, the inventor thought and created the invention shown below.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.

<Embodiment 1>
FIG. 1 is a cross-sectional view of imaging device 100 according to the present embodiment as viewed from above. FIG. 2 is a cross-sectional view of the imaging apparatus 100 according to the present embodiment as viewed from the front direction (subject direction). 1 and 2 also show the x direction, the y direction, and the z direction.

  As shown in FIG. 1, the imaging device 100 includes a first lens group 10, a second lens group 20, a third lens group 30, an infrared light cut filter 40, and an imaging element 50.

  As described below, imaging apparatus 100 according to the present embodiment arranges a lens group having negative power on the subject side and a lens having positive power on the imaging element 50 side, so-called retrofocus. It has a structure.

  The image sensor 50 has a light receiving surface. The image sensor 50 is an element that can convert an optical image formed on the light receiving surface into an electric signal. The light receiving surface is generally rectangular with a ratio of the long side to the short side of 4: 3 due to the limitation of the monitor that displays the image. A plan view of the image sensor 50 is shown in FIG. As shown in FIG. 3, the image sensor 50 has a rectangular light receiving surface 50a.

  The plurality of lenses (first lens group 10, second lens group 20, and third lens group 30) are members that form an image of a subject on the light receiving surface 50 a of the image sensor 50.

  The first lens group 10 has a function of turning the optical axis back in the vertical direction (in FIG. 1, from the optical axis 60 to the optical axis 70). The first lens group 10 has a negative power as a whole. The first lens group 10 includes a first lens 1, a prism lens 2, and a second lens 3.

  Here, the first lens 1 has negative power. The prism lens 2 has a reflecting surface that bends the optical path and a lens surface. The second lens 3 has negative power. The first lens 1 is held and fixed by a first lens holding frame 15. The entire first lens group 10 is held and fixed by a first lens group holding frame 16.

  The second lens group 20 has a positive power as a whole. The second lens group 20 includes a third lens 4 and a fourth lens 5. Here, the third lens 4 has positive power. The fourth lens 5 has negative power.

  On the subject side of the third lens 4, an aperture stop 6 for limiting incident light is disposed. The aperture stop 6 and the second lens group 20 are held and fixed by a second lens group holding frame 17.

  The third lens group 30 has a positive power as a whole, and is constituted by the fifth lens 7. Here, the third lens group 30 is held and fixed by the third lens group holding frame 18.

  Further, an infrared light cut filter 40 is disposed between the third lens group 30 and the image sensor 50. Here, the infrared light cut filter 40 has a function of blocking infrared light included in incident light. The infrared light cut filter 40 and the image sensor 50 are mounted and fixed in the image sensor package 19.

  The centers of the lenses 1 to 5 and 7 and the center of the image sensor 50 coincide with the optical axis 60 and the optical axis 70 that are the optical central axes of the image capturing apparatus 100. The first lens holding frame 15, the first lens group holding frame 16, and the image pickup device package 19 are each fixed by an outer casing 25.

  As shown in FIG. 2, two guide shafts 35 are provided in the imaging apparatus 100. Here, the guide shafts 35 are arranged at a predetermined distance from each other, and are parallel to each other. Further, the guide shaft 35 is disposed so as to be substantially parallel to the direction of the optical axis 70.

  The second lens group holding frame 17 and the third lens group holding frame 18 are formed with cylindrical guide portions or U-shaped grooves each having a predetermined length. The hollow portion or groove of the cylindrical guide portion is engaged with the guide shaft 35. That is, the hollow portion or groove can move on the guide shaft 35.

  With this configuration, the second lens group 20 and the third lens group 30 can move in the direction of the optical axis 70, and movement in other directions is restricted. A uniaxial drive device 36 is fixed to the outer casing 25, and the second lens group 20 and the third lens group 30 are movable in the direction of the optical axis 70 by the driving force of the uniaxial drive device 36. To do.

  FIG. 4 is a diagram illustrating changes in the optical lens system of the imaging apparatus 100 according to the present embodiment and the light flux width at the zoom wide end.

  As shown in FIG. 4, first, the light beam incident on the first lens group 10 from the subject side is expanded by the first lens group 10. Although not shown in FIG. 4, the light beam is bent by 90 ° by the prism lens 2 including the reflecting surface.

  Thereafter, the width of the light beam is limited in the aperture stop 6 (not shown in FIG. 4). Then, the light flux whose width is limited is imaged on the light receiving surface 50 a by the second lens group 20 and the third lens group 30. Although not shown in FIG. 4, the light beam passes through the infrared light cut filter 40 before being imaged on the light receiving surface 50a.

  Here, by changing the positions of the second lens group 20 and the third lens group 30, zooming and focus adjustment are performed.

  In the image sensor 50, a microlens is present for each pixel sensor constituting the light receiving surface 50a. Therefore, it is desirable that the incident angle (angle τ in FIG. 6) of the light emitted from the third lens group 30 to the light receiving surface 50a is smaller. This is because, when the incident angle on the light receiving surface is large, vignetting occurs in each pixel sensor, and the peripheral light amount decreases.

  From the above, in the imaging apparatus 100 according to the present embodiment, the optical system is configured so as to be image side telecentric with a small incident angle on the light receiving surface.

  In the imaging apparatus 100 according to the present embodiment, each lens (for example, the second lens 3, the fifth lens 7, etc.) disposed on the normal axis of the imaging element 50 (that is, on the optical axis 70). ) And each lens (for example, the first lens 1) disposed facing the subject (that is, disposed on the optical axis 60) is a non-circular lens.

  In the present embodiment, the discussion proceeds on the assumption that the first lens 1, the second lens 3, and the fifth lens 7 are non-circular lenses. Note that all of the lenses 1, 3, and 7 need not be non-circular lenses. Although not adopted in the present embodiment, the third lens 4 or the fourth lens 5 may be a non-circular lens.

  Here, the non-circular lens is a lens having a shape obtained by removing at least one predetermined peripheral portion from a circular lens that does not contribute to image formation on the light receiving surface.

  Hereinafter, a portion of the circular lens that does not contribute to image formation on the light receiving surface will be described.

  First, as shown in FIG. 5, a description will be given of a case where a light beam is imaged in a diagonal end region P (region farthest from the optical axis position) of the rectangular light receiving surface 50a.

  FIG. 6 is a diagram illustrating an optical lens system that forms an image of a light beam on the region P of the light receiving surface 50a at the zoom wide end, and how the light beam width changes.

  Here, the optical lens system shown in FIG. 6 has substantially the same configuration as the optical lens system shown in FIG. 4, but both optical lens systems are different in the following points. That is, the optical lens system shown in FIG. 4 includes a non-circular lens, but in the optical lens system shown in FIG. 6, all the lenses are circular lenses. Therefore, the optical lens system shown in FIG. 6 also has a retrofocus configuration and employs an image side telecentric system.

  As shown in FIG. 6, the light beam is incident on the first lens group 10 at the principal ray incident angle θd. The luminous flux is spread by the first lens group 10 having negative power. The beam width is limited by an aperture stop (not shown). Thereafter, the second lens group 20 and the third lens group 30 form an image on the region P of the light receiving surface 50a.

  As shown in FIG. 6, when the light beam forms an image on the region P of the light receiving surface 50 a, the circular light beam passes through the vicinity of the outer peripheral ends of the first lens group 10 and the third lens group 30. The size is designed.

  Now, as shown in FIG. 5, a case where a light beam forms an image in the long-side central region Q of the rectangular light receiving surface 50a will be described.

  FIG. 7 is a diagram illustrating an optical lens system that focuses a light beam on the region Q of the light receiving surface 50a at the zoom wide end, and how the light beam width changes. Here, the optical lens system shown in FIG. 6 and the optical lens system shown in FIG. 7 have the same configuration. 6 shows a cross-sectional configuration at a position away from the center of the lens, while FIG. 7 shows a cross-sectional structure near the center of the lens. Accordingly, FIGS. 6 and 7 show different cross sections.

  The light beam is incident on the first lens group 10 at the principal ray incident angle θh (the incident angle θh is smaller than the incident angle θd). The luminous flux is spread by the first lens group 10 having negative power. The beam width is limited by an aperture stop (not shown). Thereafter, the second lens group 20 and the third lens group 30 form an image on the region Q of the light receiving surface 50a.

  As shown in FIG. 7, when the light beam forms an image in the region Q of the light receiving surface 50 a, the first lens group 10 has a region located on the inner side by a distance 43 from the outer peripheral end of the first lens group 10. The light beam passes through. Further, in the third lens group 30, the light flux passes through a region located on the inner side by a distance 44 from the outer peripheral end of the third lens group 30.

  As described above, in the same optical lens system, when the imaging regions on the light receiving surface 50a are different, the optical paths in the first lens group 10 and the third lens group 30 are different. Needless to say, the values of the distances 43 and 44 increase from the diagonal end region P toward the long-side central region Q.

  As can be seen from the comparison between FIGS. 6 and 7 described above, the first lens group 10 and the circular third lens group 30 constituted by circular lenses do not contribute to image formation on the rectangular light receiving surface 50a. A portion (a portion corresponding to reference numerals 43 and 44 in FIG. 7) is generated.

  In this embodiment, a non-circular lens obtained by removing a portion that does not contribute to image formation on the light receiving surface 50a in each of the circular lenses constituting the first lens group 10 shown in FIGS. This is the first lens 1 and the second lens 3.

  Similarly, in the circular lens constituting the third lens group 30 shown in FIGS. 6 and 7, a non-circular lens in which a portion that does not contribute to image formation on the light receiving surface 50a is removed is the present embodiment. It is the 5th lens 7 concerning.

  Thus, the non-circular lens from which a part of the circular lens is removed is more compact than the circular lens.

  A method of removing a portion that does not contribute to image formation on the light receiving surface 50a from the circular lens (that is, a non-circular shape) can be arbitrarily selected. In the following, an example of a non-circular lens is shown.

  FIG. 8 is a plan view showing an embodiment of the non-circular fifth lens 7. 9 is a cross-sectional view of the non-circular lens shown in FIG. 8 taken along the line AA. FIG. 10 is a BB cross-sectional view of the non-circular lens shown in FIG.

  The non-circular fifth lens 7 shown in FIG. 8 has a D-cut shape in which a portion that does not contribute to image formation on the light receiving surface 50a is cut along a straight line from the dotted circular lens 150. . Here, the fifth lens 7 shown in FIG. 7 is D-cut at two locations in the portions a and b, but may be D-cut only at one location.

  In addition, even at the left and right ends of the non-circular fifth lens 7 shown in FIG. 7, there are few areas that do not contribute to image formation on the light receiving surface 50 a. Therefore, the fifth lens 7 having a non-circular shape having a shape as shown in FIG. 11 (that is, D-cuts are also formed at the left and right ends of the dotted circular lens 150) may be used.

  Here, when the non-circular lens having the D-cut shape shown in FIG. 8 is arranged on the normal axis of the image sensor 50 (that is, on the optical axis 70), the non-circular lens in the plan view is D-cut. It is desirable that the straight line portion and the long side of the light receiving surface 50a are substantially parallel.

  When the non-circular lens is disposed facing the subject (that is, disposed on the optical axis 60), the straight portion of the D-cut portion of the non-circular lens in plan view and the light receiving surface 50a. It is desirable that the long side of the is substantially parallel.

  Here, it is desirable that the diameter of the circular lens 150 as a base is substantially the same as the diagonal line of the imaging surface 50a.

  That is, when the image-side telecentric method is employed in which the incident angle of the light beam on the light receiving surface 50a (angle τ shown in FIG. 6) is small, the principal ray of the light beam is between the third lens group 30 and the light receiving surface 50a. In FIG. 4, the optical axis is substantially parallel to the optical axis. Accordingly, the size of the lens diameter needs to be at least substantially the same as the diagonal line of the light receiving surface 50a. In consideration of the compactness of the lens, it is not desirable that the size of the lens diameter exceeds the diagonal length of the light receiving surface 50a more than necessary.

  From the above, in the imaging apparatus 100 according to the present embodiment of the image side telecentric method, the diameter of the circular lens 150 that serves as the base of the non-circular lens is set to be smaller than that of the light receiving surface 50a. It is desirable that the value be almost the same as the diagonal line.

  In the case where the imaging device is configured with a circular lens, an outline of the light beam imageable area A1 with respect to the light receiving surface 50a is as shown in FIG. On the other hand, when the imaging device 100 including a non-circular lens is configured, the outline of the light beam imageable area A2 with respect to the light receiving surface 50a is as shown in FIG.

  As can be seen from FIG. 13, even if a non-circular lens is adopted, only the useless imageable area is reduced, and the image formation on the light receiving surface 50a is not affected. That is, by employing a non-circular lens, the surface area of the lens can be reduced without affecting the image formation on the light receiving surface 50a.

  As described above, the imaging device 100 according to the present embodiment employs a non-circular lens.

  Therefore, the surface area of the lens can be made smaller than that of the circular lens without degrading the optical performance (that is, without affecting the image formation on the light receiving surface 50a). Then, by reducing the surface area of the lens, it is possible to reduce or reduce the thickness of the imaging apparatus 100 whose dimensions are controlled by the size of a predetermined lens.

  In addition, in imaging device 100 according to the present embodiment, a D-cut lens is employed as the non-circular lens.

  Therefore, it is possible to easily create a non-circular lens in which a portion that does not contribute to image formation from the circular lens to the light receiving surface 50a is removed.

  In the imaging apparatus 100 according to the present embodiment, the non-circular lenses (for example, the second lens 3 and the fifth lens 7) are arranged on the normal axis of the imaging element 50 (that is, on the optical axis 70). It is installed. Further, the straight portion of the non-circular lenses 5 and 7 in the D-cut portion in plan view and the long side of the light receiving surface 50a are substantially parallel.

  Therefore, the imaging device 100 in the y direction in FIG. 1 can be thinned.

  That is, as shown in FIG. 14, it is assumed that the long side L1 of the rectangular light receiving surface 50a and the straight line portion L2 of the D-cut portion of the non-circular lens 7 in plan view are not parallel. In this case, as apparent from FIG. 14, the imaging device 100 cannot be thinned in the y direction.

  However, as shown in FIG. 15, it is assumed that the long side L1 of the rectangular light receiving surface 50a and the straight line portion L3 of the D-cut portion of the non-circular lens 7 in plan view are parallel. Then, as apparent from the comparison between FIGS. 14 and 15, the imaging device 100 can be thinned in the y direction.

  As described above, the lenses 4 and 5 constituting the second lens group 20 may be non-circular lenses. However, since the lenses 4 and 5 are close to the aperture stop 6, the effect of reducing the thickness of the imaging device 100 is not so great.

  On the other hand, the thickness of the imaging device 100 is regulated by the third lens 3 and the fifth lens 7. Therefore, the third lens 3 and the fifth lens 7 are non-circular lenses, which contributes to the thinning of the imaging device 100.

  In the imaging apparatus 100 according to the present embodiment, the non-circular lens (for example, the first lens 1) is disposed facing the subject (that is, disposed on the optical axis 60). . Further, the straight portion of the non-circular lens 1 that is D-cut in plan view and the long side of the light receiving surface 50a are substantially parallel.

  Therefore, the surface area of the first lens 1 can be reduced without degrading the optical performance (that is, maintaining a wide angle of view and without affecting the image formation on the light receiving surface 50a). .

  That is, as shown in FIG. 16, it is assumed that the long side L1 of the rectangular light receiving surface 50a and the straight line portion L5 of the D-cut portion of the noncircular lens 1 in plan view are not parallel. In this case, even if the optical performance is not deteriorated, as is apparent from FIG. 16, the surface area of the first lens 1 cannot be reduced so much.

  However, as shown in FIG. 17, it is assumed that the long side L1 of the rectangular light receiving surface 50a and the straight line portion L6 of the D-cut portion of the non-circular lens 1 in plan view are parallel. If it does so, the surface area of the 1st lens 1 can be made small enough as it is clear also from the comparison of FIG.

  And since the surface area of the 1st lens 1 became small, size reduction of the 1st lens group 10 whole is also attained.

  That is, for example, when both the first lens 1 and the second lens 3 are circular lenses, the first lens group 10 has a cross-sectional structure as shown in FIG. In the case of the structure shown in FIG. 18, downsizing of the first lens group 10 is limited due to contact between both lenses in the proximity portion 57 between the first lens 1 and the second lens 3. .

  However, when the first lens 1 and the second lens 3 are non-circular lenses, the first lens group 10 has a cross-sectional structure as shown in FIG. That is, contact between the two lenses is eliminated, and the first lens group 10 can be downsized.

  Even if only the first lens 1 is a non-circular lens, the first lens group 10 can be downsized.

  Incidentally, the non-circular lens may be disposed only on the optical axis 70 of the imaging device 50, or the non-circular lens may be disposed only on the optical axis 60. In the former case, the imaging device 100 can be mainly reduced in thickness. On the other hand, in the latter case, the first lens group 10 can be mainly downsized.

  As can be understood from the above consideration, as in the above embodiment, the non-circular lens is disposed on the normal axis of the image sensor 50 (that is, on the optical axis 70), and the non-circular lens faces the subject. By disposing (i.e., disposing on the optical axis 60), the imaging device 100 can be made thinner and the first lens group 10 can be made smaller.

  If the first lens 1 or the second lens 3 is a non-circular lens as described above, the size of the first lens group 10 is not changed, and only the size of the prism lens 2 is used. Can be miniaturized.

  Thus, when only the size of the prism lens 2 is reduced, the distance between the prism lens 2 and the first lens 1 or the distance between the prism lens 2 and the second lens 3 is increased. . Therefore, since the degree of freedom in lens arrangement design can be increased, the optical performance of the imaging apparatus 100 can be improved.

  In the imaging device 100 according to the present embodiment, the first lens group 10 has negative power. Therefore, the surface area of the first lens 1 and the surface area of the second lens 3 constituting the first lens group 10 can be further reduced.

  That is, when the first lens group 10 has a positive power, the light beam that is incident on the first lens group 10 and contributes to image formation becomes thick. This is because the size of the aperture stop 6 cannot be changed in design. Thus, when the luminous flux becomes thick, the area of the first lens 1 and the second lens 3 that can be removed from the circular lens (that is, the portion that does not contribute to image formation on the light receiving surface 50a) decreases.

  However, as described above, when the first lens group 10 has negative power, the light beam that is incident on the first lens group 10 and contributes to image formation becomes thin. Therefore, in the first lens 1 and the second lens 3, the area of a portion that can be removed from the circular lens (that is, a portion that does not contribute to image formation on the light receiving surface 50a) increases. That is, the surface area of the first lens 1 and the surface area of the second lens 3 can be further reduced.

  Further, in imaging device 100 according to the present embodiment, the non-circular lens is D-cut at two opposing positions as shown in FIG. Therefore, the surface area of the lens can be made smaller than a non-circular lens that is D-cut only at one place.

  Note that a portion of the reflecting surface of the prism lens 2 that does not contribute to image formation on the light receiving surface 50a can be deleted.

  Further, when the non-circular lens is made of plastic, it is not desirable to make the portion removed from the circular lens extremely large for the following reason.

  That is, when the non-circular lens is made of plastic, the more the shape of the non-circular lens is different from the circular shape, the more uneven the flow of the resin and the cooling method occur.

  However, if there are few parts to be removed, it is possible to prevent the formation accuracy from deteriorating. That is, the error between the design dimension and the actual dimension can be reduced.

It is sectional drawing which shows the structure at the time of seeing the imaging device 100 which concerns on embodiment from upper direction. It is sectional drawing which shows the structure at the time of seeing the imaging device 100 which concerns on embodiment from the front. It is a top view which shows the structure of an imaging device and a rectangular light-receiving surface. It is a figure for demonstrating the mode of the change of the light beam in the imaging device which concerns on embodiment. It is a top view which shows the area | region of the image formation position in a light-receiving surface. It is a figure for demonstrating the part which does not contribute to the image formation to a light-receiving surface in a circular lens. It is a figure for demonstrating the part which does not contribute to the image formation to a light-receiving surface in a circular lens. It is a top view which shows the difference of the shape of a circular lens and a non-circular lens. It is sectional drawing which shows one cross-sectional shape of a non-circular lens. It is sectional drawing which shows the other cross-sectional shape of a non-circular lens. It is a top view of a non-circular lens obtained by D-cutting a circular lens from four directions. It is a figure which shows the image formation possible area at the time of using a circular lens. It is a figure which shows the image formation possible area at the time of using the non-circular lens by which D cut was carried out. It is a figure for demonstrating thickness reduction of the predetermined direction of an imaging device. It is a figure for demonstrating thickness reduction of the predetermined direction of an imaging device. It is a figure for demonstrating size reduction of a 1st lens. It is a figure for demonstrating size reduction of a 1st lens. It is a figure for demonstrating size reduction of a 1st lens group. It is a figure for demonstrating size reduction of a 1st lens group.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lens, 2 Prism lens, 3 2nd lens, 4 3rd lens, 4th lens, 6 Aperture stop, 7 5th lens, 10 1st lens group, 15 1st lens Holding frame, 16 First lens group holding frame, 17 Second lens group holding frame, 18 Third lens group holding frame, 19 Imaging device package, 20 Second lens group, 25 Outer casing, 30 Third lens Lens group, 35 guide shaft, 36 uniaxial driving device, 40 infrared light cut filter, 50 imaging element, 50a light receiving surface, 60, 70 optical axis, 100 imaging device, 150 circular lens.

Claims (6)

An imaging element having a rectangular light-receiving surface and converting an optical image formed on the light-receiving surface into an electrical signal;
A plurality of lenses for forming an image of a subject on the light receiving surface;
Has
At least one of the plurality of lenses is
It is composed of a non-circular lens having a shape obtained by removing at least one predetermined peripheral portion from a circular lens that does not contribute to image formation on the light receiving surface.
An imaging apparatus characterized by that. The predetermined peripheral portion is
Having a D-cut shape obtained by cutting an arc portion of a circular lens along a straight line;
The imaging apparatus according to claim 1. The non-circular lens is
Disposed on the normal axis of the image sensor;
The straight portion of the D-cut portion of the non-circular lens in plan view and the long side of the light receiving surface are substantially parallel.
The imaging apparatus according to claim 2. The plurality of lenses include
A lens group having a function of bending the optical axis and having the non-circular lens is included;
The non-circular lens is disposed facing the subject;
The straight portion of the D-cut portion of the non-circular lens in plan view and the long side of the light receiving surface are substantially parallel.
The imaging apparatus according to claim 2. The lens group has negative power;
The imaging apparatus according to claim 4. The non-circular lens is
In the two opposing locations, the D-cut is performed.
The imaging apparatus according to claim 2, wherein the imaging apparatus is an imaging apparatus.

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