JP5114838B2 - Image plane conversion element, method of manufacturing the element, and optical system having the element - Google Patents

Description

  The present invention relates to a technique for improving image quality in an imaging optical system using an imaging element such as a CCD.

Conventionally, in an optical system that acquires an image with an image sensor, the light receiving element of the image sensor is arranged on a plane, so that the image plane of the optical system is limited to a plane and the amount of field curvature aberration is suppressed to a predetermined value or less. It is optically designed. In addition, an image correction apparatus for reducing the distortion of a projected image when an image is projected onto a dome-shaped screen or the like in a projection optical system has been proposed (see Patent Document 1).
JP 2000-39586 A

  However, in order to suppress the amount of field curvature aberration to a predetermined amount or less in the optical system, a negative refractive curved surface having a strong curvature exists in the imaging optical system, or a curved surface having positive refractive power and a negative curved surface are negative. It is necessary to take a configuration such as sufficiently widening the distance from the curved surface having a refractive power of. For this reason, the imaging optical system with a small image surface curvature aberration has drawbacks such as an increase in the number of constituent lens surfaces and a tight manufacturing tolerance of the optical system.

  In the disclosed example of Patent Document 1, the amount of field curvature aberration in the image plane of the optical system is not considered. In addition, if a commercially available fiber bundle is used, it is difficult to accurately manufacture the position of each light transmission tube at the exit end according to the size and pitch of the light receiving element of the imaging device. There is a problem that the position of the light emitting end of the tube and the alignment of the light receiving element are inaccurate, and moire occurs in the output image.

  The present invention has been made in view of the above problems, and is arranged between an image plane of an imaging optical system having field curvature aberration and an image pickup element to eliminate the field curvature aberration and to obtain a good image. An object of the present invention is to provide an image plane conversion element that enables imaging, a method for manufacturing the image plane conversion element, and an optical system having the image plane conversion element.

In order to solve the above problems, the present invention provides:
It is arranged between the image plane of the imaging optical system and the image sensor, and consists of a plurality of light transmission tubes that are opposed to each other and formed non-intersecting with each other .
The light transmission tube comprises a transparent substrate and a polymer member bonded to the transparent substrate,
The first surface molded into the light transmission tube is molded into a curved surface corresponding to the field curvature aberration in the image surface,
The second surface, which is formed to face the first surface and is the envelope surface of the aggregate of the end surfaces of the light transmission tube, is formed substantially parallel to the envelope surface of the light receiving element of the imaging element,
It said second surface provides an image plane conversion element characterized Rukoto formed in the transparent substrate.

  In addition, the present invention provides an optical system including an imaging optical system, the image plane conversion element, and an imaging element in order from the object side.

  The present invention also provides an optical system comprising means for moving the first surface of the image plane conversion element in a direction perpendicular to the optical axis.

The present invention also provides:
A method for manufacturing an image plane conversion element, which is disposed between an image plane of an imaging optical system and an image sensor, and forms a plurality of light transmission tubes that respectively face the plurality of light receiving elements of the image sensor so as not to intersect each other. ,
A molding step of molding the surface on the image plane side, which is the first surface of the polymer member on which the light transmission tube is formed, into a curved surface corresponding to the field curvature aberration of the imaging optical system with a mold;
An adhesion step of adhering a plane facing the first surface of the polymer member to a transparent substrate;
The light transmission tube is formed from the polymer member and the transparent substrate, and a second surface, which is an envelope surface of the aggregate of end surfaces of the light transmission tube, is formed substantially parallel to the envelope surface of the light receiving element of the imaging element. And a processing step of forming the second surface in the transparent substrate . A method of manufacturing an image plane conversion element is provided.

  According to the present invention, an image plane conversion element that is disposed between an image plane of an imaging optical system having a field curvature aberration and the image sensor and eliminates the field curvature aberration and enables a good image to be captured. A method for manufacturing the image plane conversion element and an optical system having the image plane conversion element can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a state in which the image plane conversion element according to the first embodiment of the present invention is disposed between the image plane of the imaging optical system and the image pickup element. FIG. 2 is an enlarged cross-sectional view of the image plane conversion element and the imaging element in FIG.

  1 and 2, the image plane conversion element 1 according to the first embodiment of the present invention is between an image plane I of the imaging optical system 3 and an imaging element 5 (for example, CCD, CMOS element, etc.). Has been placed. The image plane conversion element 1 includes a rod-shaped or fiber-shaped light transmission tube 7, and a first surface 7 a formed by an end surface of the light transmission tube 7 forms a surface on which light from the imaging optical system 3 is incident. is doing. The first surface 7a is formed in a surface shape corresponding to the field curvature aberration of the image forming optical system 3 on the image surface I of the image forming optical system 3, and faces the first surface 7a and is formed on the end surface of the light transmission tube 7. A second surface 7 b that is an envelope surface of the aggregate is formed substantially parallel to the envelope surface of the light receiving element 5 a of the image sensor 5. When the end surface of the light transmission tube 7 is a flat surface, the envelope surface is a flat surface. When a plurality of curved surfaces such as a microarray lens are present on the end surface of the light transmission tube 7, the envelope surface is a surface in contact with the plurality of curved surfaces. Similarly, the envelope surface of the light receiving element 5a is a plane when the surface of the light receiving element 5a is a flat surface, and when there are a plurality of curved surfaces such as a microarray lens, the envelope surface is a surface in contact with the plurality of curved surfaces.

  In addition, you may have the supporting member 7c formed in the surface of the 1st surface 7a with the transparent resin etc. for protecting the end surface of the light transmission tube 7, and supporting the light transmission tube 7. Since the imaging optical system 3 has a depth of focus, it is not necessary to manufacture the surface accuracy of the surface of the first surface 7a and the surface of the support member 7c with a particularly high level. The support member 7c may be provided in the vicinity of the first surface 7a so as to support the light transmission tube 7 so that the first surface 7a of the light transmission tube 7 is exposed.

  Each light transmission tube 7 of the image plane conversion element 1 is disposed on the second surface 7 b so that the end face of each light transmission tube 7 faces the respective light receiving elements 5 a of the imaging device 5. That is, each light transmission tube 7 is arranged so as to have a one-to-one relationship with each light receiving element 5a. The light transmission tube 7 is formed with an area corresponding to the light receiving element 5a corresponding to RGB1 pixel and a pitch corresponding to the pitch of the light receiving elements 5a. Further, each light transmission tube 7 is formed without intersecting from the first surface 7a side to the second surface 7b side. As a result, the light incident on the first surface 7a is transmitted through the respective light transmission tubes 7, and the position of the light incident from the imaging optical system 3 on the image surface I does not intersect in the middle of the second surface. Since the light is emitted from 7b to the opposing light receiving element 5a, the captured image is not disturbed.

  The light receiving element 5a has an array lens 5b, and the emission end face of the light transmission tube 7 on the second surface 7b side is disposed at a position conjugate with the light receiving element 5a, and each light transmission tube 7 on the second surface 7b. The light emitted from the emission end face is efficiently condensed on each of the opposing light receiving elements 5a. The second surface 7b is formed in a flat surface or a curved surface corresponding to the envelope surface formed by the light receiving element 5a. On the second surface 7b side, a substrate 7d such as thin glass or plastic is disposed, and the light transmission tube 7 is fixed and supported at a predetermined position. When the light receiving element 5a does not have the array lens 5b, an array is formed on the light receiving element 5a side of the substrate 7d so that the light emitting element 5a is conjugate to the light emitting element 7a on the second surface 7b side. It is also possible to arrange the lens 7e. Further, the array lens 7e on the light receiving element 5a side of the substrate 7d and the array lens 5b of the light receiving element 5a may be configured so that the emission end face of the light transmission tube 7 and the light receiving element 5a are in a conjugate position. In this way, the image plane conversion element 1 is formed, and an optical system including the image plane conversion element 1 is configured. The array lens 5b or 7e may not be provided. In this case, the light-emitting element 7a and the light-receiving element 5a on the second surface 7b side receive light from the light-transmitting tube 7 as another light-receiving element. What is necessary is just to arrange | position the image surface conversion element 1 and the image pick-up element 5 so that it may adjoin enough so that it may not leak to 5a in large quantities.

  In order to obtain good imaging performance on the image plane I of the imaging optical system 3, the imaging optical system 3 is configured to correct various aberrations. In order to minimize the field curvature aberration among aberrations, the Petzval sum of the imaging optical system 3 must be close to zero. For this purpose, the imaging optical system 3 as a whole requires a surface element having a predetermined positive refractive power and a negative refractive power. In order to minimize the curvature of field, many optical elements are required, and when the entire imaging optical system 3 is enlarged, the cost is increased. In particular, in the imaging optical system 3 having a short overall length, it is necessary to increase the curvature of the surface of the negative refractive power in order to make the Petzval sum close to zero while ensuring a predetermined power of the entire imaging optical system 3. If there is an element having a large curvature of the surface, various aberrations are likely to occur, and it is difficult to obtain desired imaging performance.

  In the image plane conversion element 1 according to the present embodiment, the first surface 7 a of the image plane conversion element 1 arranged on the image plane I of the imaging optical system 3 is the image plane on the image plane I of the imaging optical system 3. Since the curved surface corresponding to the curvature aberration is formed, an image focused on the first surface 7a (an image with the smallest curvature of field curvature) is formed. Light from this image is transmitted through the respective light transmission tubes 7 to the second surface 7b, emitted from the respective light transmission tubes 7, and opposed to the respective light transmission tubes 7 via the array lenses 7e and 5b. The received light is received by the light receiving element 5a to obtain a captured image. If the first surface 7a is within the focal depth of the imaging optical system 3, a good focused image can be obtained. Therefore, it is not necessary to increase the surface accuracy of the first surface 7a, and the surface processing is easy and low. Costing can be achieved.

  In FIG. 1 and the subsequent drawings, the size of each element of the image plane conversion element is shown enlarged for convenience of explanation.

  FIGS. 3A to 3C are views showing various shapes of the light transmission tube 7 constituting the image plane conversion element 1.

  FIG. 3A shows that the surface of the light transmission tube 7 on the first surface 7a side (denoted by the same reference numeral 7a) and the surface of the second surface 7b side (denoted by the same reference numeral 7b) are the axes O of the light transmission tube 7. It is formed substantially perpendicular to. The light incident on the surface 7a of the light transmission tube 7 is transmitted to the surface 7b by repeating total reflection on the side surface of the light transmission tube 7, and is emitted from the surface 7b toward the light receiving element 5a. Since the surface 7a and the surface 7b are formed substantially perpendicular to the axis O, the light incident angle on the surface 7a and the light emitting angle on the surface 7b are substantially equal. When the curvature of the first surface 7a formed corresponding to the field curvature aberration is gentle and can be regarded as a flat surface across the surface 7a of one light transmission tube 7, the light transmission tube 7 having such a shape is used. A sufficient effect can be obtained.

  In FIG. 3B, the surface 7a of the light transmission tube 7 is formed so as to be inclined in the direction in which the incident angle of incident light increases. When the surface 7a is formed so as to be inclined in this way, the angle formed with respect to the axis O of the light transmitted through the light transmission tube 7 is reduced, and the spread of the emitted light from the surface 7b can be suppressed. Further, since leakage light from the side surface is suppressed, mutual interference between adjacent light transmission tubes 7 can be suppressed, and a high-quality image can be obtained.

  In FIG. 3C, the surface 7a of the light transmission tube 7 is convex on the object side, and the portion 7f of the surface 7a facing the optical axis 2 side of the imaging optical system 3 is formed on the concave surface. This is to reduce the angle between the light incident on the side of the adjacent light transmission tube 7 and the light axis O of the light transmission tube 7.

  Further, even when the optical system is deviated from telecentricity, the surface 7a of each light transmission tube 7 is appropriately inclined according to the distance from the optical axis 2 of the imaging optical system 3 to the light receiving element 5a. It is possible to transmit the light without increasing the inclination angle. When the telecentric conditions for the optical system are relaxed, it is possible to design the entire length of the optical system to be shorter.

  The cross-sectional shape perpendicular to the axis O of the light transmission tube 7 is not limited to a quadrangle, and may be a polygon such as a circle or a hexagon, and is formed in accordance with the shape of the light receiving element 5a.

  FIG. 4 shows an optical system having an image plane conversion element according to the second embodiment of the present invention. FIG. 4A shows a state in which the image plane conversion element is arranged between the image plane and the image pickup element. ) Shows the schematic shape of the light transmission tube. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 4, as the image size is smaller, the burden on the imaging optical system 3 is reduced. As the overall size of the image sensor 5 is larger, a larger number of pixels (the number of light receiving elements 5a) can be realized. As a method of simultaneously satisfying these requirements, the thickness (area) of the second surface 17b side surface (denoted by the same reference numeral 17b) of the light transmission tube 17 constituting the image plane conversion element 11 is set to the first surface 17a side surface ( It is made thicker (wider) than the thickness (area) of the same symbol 17a. In FIG. 4B, the light transmission tube 17 has a substantially trapezoidal cross section along the axis O. In this case, the divergence angle of the light emitted from the surface 17b of the light transmission tube 17 can be made smaller than the divergence angle of the incident light, and the light from the surface 17b is incident on the light receiving element 5a at an angle close to vertical. Therefore, it becomes difficult to be influenced by reflection by the surface structure portion of the image sensor 5.

  As can be seen from FIG. 4B, when the thickness of the light transmission tube 17 gradually increases from the surface 7a to the surface 7b, the light transmission tube of light traveling while reflecting the inside of the light transmission tube 17 is used. 17 with respect to the axis O becomes smaller, the spread of the light emitted from the surface 17b in the traveling direction becomes smaller, stray light to the adjacent light transmission tube 17 is reduced, and the incident angle with respect to the light receiving element 5a is further increased. A bundle of luminous fluxes can be formed. Thus, even in the case of a small image plane I (image size) where the burden on the imaging optical system 3 is light, it is possible to use the imaging element 5 having a large number of images (the number of light receiving elements 5a).

  Contrary to the above, the thickness (area) of the surface 7a is made thicker than the thickness (area) of the surface 7b, so that the large image plane I can be imaged by the small image sensor 5. .

  FIG. 5 shows an optical system having an image plane conversion element according to the third embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 5, in the third embodiment, the light transmission tube 27 is not formed in the portion (nearly zero) where the field curvature aberration is small, but the light transmission tube 27 is a flat surface and only the peripheral portion where the field curvature aberration is large. 27 is formed. In this manner, the omission of the light transmission tube 27 with a small field curvature aberration facilitates the manufacture of the image plane conversion element 21. Other configurations, operations, and effects are the same as those in the first embodiment, and a description thereof will be omitted.

  FIG. 6 shows an optical system having an image plane conversion element according to the fourth embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 6, the image plane conversion element 31 moves the first surface 7 a of the image plane conversion element 31 in the four corners of the support member 7 c shown in FIG. 2 in a direction perpendicular to the optical axis of the imaging optical system 3. It has the connection part 30 connected to. The moving means 33 is configured to be able to move the first surface 7a of the image plane conversion element 33 in two orthogonal axial directions in a plane perpendicular to the optical axis. The first surface 7a of the image plane converting means 31 is moved via the moving means 33 with respect to the blur of the optical system detected by the image plane converting means 31 configured as described above via the camera shake detecting means (not shown). An optical system capable of performing camera shake correction by moving in a direction perpendicular to the optical axis can be configured. Since the image plane conversion element 31 is small and lightweight, the driving force is small and the moving means 33 can be reduced in size and speed.

  FIG. 7 shows an optical system having an image plane conversion element according to the fifth embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 7, the image plane conversion element 41 is configured by providing a light shielding member 48 made of a substance that absorbs light in a part or all of the side surface of each light transmission tube 7. By providing the light blocking member 48 on the side surface of the light transmission tube 7 in this way, interference of light between the light transmission tubes 7 can be suppressed, and stray light from the outside of the image plane conversion element 41 is received by the light receiving element 5a. Can be prevented from reaching the light receiving surface, and a high-quality image can be obtained. The light transmission tube 7 may be integrally fixed by providing the light shielding member 48 with a function of fixing the light transmission tube 7.

  Moreover, it is desirable that the variation in the thickness of the light transmission tube in the above embodiment is within ± 5%. When the variation in thickness exceeds ± 5%, the light receiving area of the light transmission tube changes, and it becomes difficult to obtain an image with high variation in the amount of light directed toward the light receiving element.

  Further, it is desirable that the variation in the separation interval of the light transmission tube is within ± 5%. When the variation in separation interval exceeds ± 5%, the light receiving area of the light transmission tube changes, and it becomes difficult to obtain an image with high variation in the amount of light directed toward the light receiving element.

  Further, it is desirable that the variation in the distance (pitch) between the axes of the light transmission tube is within ± 5%. If the variation in the distance between the axes exceeds ± 5%, the light transmission tube and the light receiving element are displaced from each other, and the light interference from the adjacent light transmission tube increases, which is not preferable.

  Next, embodiments of an optical system using the image plane conversion element according to the present invention will be described with reference to the drawings.

In each of the following embodiments, the aspherical surface has a height in the direction perpendicular to the optical axis y, and the distance (sag) along the optical axis from the tangent plane of each vertex of the aspherical surface to each aspherical surface at the height y. When the quantity) is S (y), the radius of curvature of the reference sphere (vertex radius of curvature) is R, the conic constant is K, and the nth-order aspherical coefficient is Cn, the following equation is used.
S (y) = (y ² / R) / {1+ (1− (1 + K) × y ² / R ² ) ^1/2 }
+ C4 × y ⁴ + C6 × y ⁶ + C8 × y ⁸ + C10 × y ¹⁰
In each example, the secondary aspherical coefficient C2 is 0, and the vertex curvature radius R and the paraxial curvature radius r coincide with each other.

(First embodiment)
8 and 9 show a first example of an optical system using the image plane conversion element according to the embodiment of the present invention. FIG. 8 is a schematic configuration diagram of an optical system including an image sensor, and FIG. 9 is a schematic configuration diagram of the optical system up to the image plane. The first embodiment shows a case where the field curvature aberration on the image plane of the imaging optical system becomes a convex shape.

  8 and 9, the optical system 100 includes, in order from the object side, an aperture stop S, a cube beam splitter QBS, a concave reflecting mirror M, an image plane conversion element 101, and an imaging element 5. . In the present optical system, the shape of the field curvature on the image plane I has a convex shape on the object side, and the first surface 107a of the image plane conversion element 101 has a shape corresponding to the image plane distortion on the image plane I. Is formed.

  The light from the object is limited by the aperture stop S and enters the cube beam splitter QBS. The incident light is transmitted through the beam splitter BS, is incident on the concave reflecting mirror M, is reflected, is incident on the beam splitter BS again, is deflected by approximately 90 degrees, and is reflected downward in the drawing. An image is formed on each light transmission tube 7 of the surface 107a. Light from the image is transmitted through the respective light transmission tubes 7, emitted from the second surface 107b toward the light receiving elements 5a facing the respective light transmission tubes 7, and received by the light receiving elements 5a. Since the shape of the first surface 107a of the image plane conversion element 101 is formed so as to eliminate the field curvature aberration of the imaging optical system 3, the light receiving element 5a has a high image quality in which the field curvature aberration is eliminated. An image is obtained.

  The beam splitter BS is formed of a semi-transmissive surface, and the light reaching the first surface 107a of the image plane conversion element 101 is approximately 25% of the incident light. In addition, the incident light quantity to the 1st surface 107a can be raised by arrange | positioning the quarter wavelength plate between the polarizing beam splitter and the concave reflecting mirror M by using the beam splitter BS as a polarizing beam splitter.

  Table 1 below provides values of specifications of the optical system according to the first example. In (Overall specifications) in the table, f is the focal length, F.F. NO represents each F number. In (lens data), the surface number is the order of the lens surfaces from the object side along the direction in which the light beam travels, the radius of curvature is the radius of curvature of the lens surfaces, the surface interval is the lens surface interval, the refractive index and the Abbe Each number represents a value for the d-line (λ = 587.6 nm). The image plane I indicates the radius of curvature of the image plane. The Petzval sum indicates the Petzval sum in the imaging optical system 3. Note that the refractive index of air of 1.000 000 is omitted, and the radius of curvature “∞” represents a plane. (Aspherical data) shows values of the conic constant K and the aspherical constants C4 to C10, respectively.

  In addition, in all the following specification values, “mm” is generally used as the focal length f, the radius of curvature, the surface interval and other lengths, etc. unless otherwise specified. Even if proportional reduction is performed, the same optical performance can be obtained. Further, the unit is not limited to “mm”, and other appropriate units may be used. In addition, the description of these symbols is the same in the following other embodiments, and the description is omitted.

(Table 1)
(Overall specifications)
f = 7.91mm
F.NO = 1.582
Horizontal half field angle ω = 20 degrees Vertical half field angle ω = 15 degrees (lens data)
Surface number Curvature radius Surface spacing Refractive index Abbe number
1: ∞ 5.377800 Aperture stop S
2: ∞ 10.000000 1.5168 64.1
3: -23.99578 -5.000000 1.5168 64.1 Reflecting surface M
4: ∞ 5.000000 1.5168 64.1 Beam splitter BS
5: ∞ 1.317173
Image plane I 19.42367
Petzval sum = 0.05495
(Aspheric data)
{3 sides}
K C4 C6 C8 C10
0.000000 0.906482E-05 -0.271319E-06 0.449536E-08 -0.254866E-10

  10A and 10B are diagrams showing the curvature aberration of the first embodiment, where FIG. 10A is a view of curvature aberration when the image plane I is a plane, and FIG. 10B is a light receiving surface of the image plane conversion element, that is, a bent image. Curve aberration diagrams when the image is formed on the surface I are shown. In the curved aberration diagram, X represents a value in the sagittal direction, and Y represents a value in the meridional direction. In the other embodiments, the same reference numerals are used and the description thereof is omitted.

  As shown in FIG. 8, by disposing the image plane conversion element 101 according to the present invention between the image plane I of the imaging optical system 3 and the imaging element 5, the optical system according to the first embodiment is It can be seen that the field curvature aberration shown in FIG. 10A can be eliminated as shown in FIG. 10B, and a high-quality image can be obtained.

(Second embodiment)
11 and 12 show a second example of the optical system using the image plane conversion element according to the embodiment of the present invention. FIG. 11 is a schematic configuration diagram of an optical system including an image sensor, and FIG. 12 is a schematic configuration diagram of the imaging optical system 3 up to the image plane. In the second example, the case where the field curvature aberration on the image plane I of the imaging optical system 3 is concave is shown.

  11 and 12, an optical system 200 includes, in order from the object side, a cemented lens of a negative meniscus lens L1 having a convex surface facing the object side and a biconvex positive lens L2 having a stronger convex surface facing the object side. The image plane conversion element 1 and the imaging element 5 are included. An aperture stop S is disposed on the cemented surface between the negative meniscus lens L1 and the biconvex positive lens L2. In this optical system, the shape of the field curvature aberration on the image plane I has a concave shape on the object side, and the first surface 7a of the image plane conversion element 1 has a shape corresponding to the image plane distortion on the image plane I. Is formed.

  Light from the object forms an image on each light transmission tube 7 of the first surface 7a of the image plane conversion element 1 through the negative meniscus lens L1, the aperture stop S, and the biconvex positive lens L2. Light from the image is transmitted through the respective light transmission tubes 7, emitted from the second surface 7b toward the light receiving elements 5a facing the respective light transmission tubes 7, and received by the light receiving elements 5a. Since the shape of the first surface 7a of the image plane conversion element 1 is formed so as to eliminate the field curvature aberration of the imaging optical system 3, the light receiving element 5a has a high image quality in which the field curvature aberration is eliminated. An image is obtained.

  Table 2 below provides values of specifications of the optical system according to the second example.

(Table 2)
(Overall specifications)
Entrance pupil diameter 2.57mm
f = 7.91mm
F. No = 2
Maximum half angle of view ω = 45
(Lens data)
Surface number Curvature radius Surface spacing Refractive index Abbe number
1: 3.60544 1.528185 1.722498 29.6
2: 2.06702 3.178679 1.542496 62.9 Aperture stop S
3: -4.59335 2.862011
Image plane I -6.33419
Petzval sum = -0.16013
(Aspheric data)
{1 side}
K C4 C6 C8 C10
0.000000 -0.181577E-02 0.893504E-04 -0.371334E-04 0.000000E + 00
{3 sides}
K C4 C6 C8 C10
0.000000 0.285013E-02 -0.852893E-05 0.646081E-05 0.000000E + 00

  FIGS. 13A and 13B are diagrams showing the curvature aberration of the second embodiment. FIG. 13A is a diagram showing the curvature aberration when the image plane I is a plane, and FIG. 13B is the light receiving surface of the image plane conversion element, that is, a curved image. Curve aberration diagrams when the image is formed on the surface I are shown.

  As shown in FIG. 11, by disposing the image plane conversion element 1 according to the present invention between the image plane I of the imaging optical system 3 and the imaging element 5, the optical system according to the second embodiment is It can be seen that the field curvature aberration shown in FIG. 13A can be eliminated as shown in FIG. 13B, and a high-quality image can be obtained.

  Next, a method for manufacturing an image plane conversion element according to an embodiment of the present invention will be described with reference to the drawings.

  The image plane conversion element can be manufactured by forming a curved surface corresponding to the field curvature aberration of the imaging optical system on a bundle of thin rods or fibers having the same area as the light receiving element of the image sensor. It is.

  At this time, after bundling light transmission tubes such as optical fibers corresponding to the number of light receiving elements of the selected image sensor, a light transmission tube group is manufactured that is uniformly stretched to have the entire size of the light receiving elements of the image sensor. It is possible. However, in such a manufacturing method, the area of the light transmission tube and the area of the light receiving element are matched, and the distance (pitch) between the centers of the light transmission tubes facing each light receiving element is matched with the distance between the centers of the light receiving elements. In addition, it is difficult to match the separation interval between the light receiving elements and the separation interval of the light transmission tube. As a result, moire occurs due to a slight shift between the position of the light transmission tube and the position of the light receiving element, leading to degradation of image quality.

  In the method for manufacturing an image plane conversion element described below, the area of the light transmission tube and the area of the light receiving element are substantially matched, the pitch deviation between them is minimized, and the separation interval can be made substantially the same. Can be manufactured.

(First manufacturing method)
FIGS. 14A to 14D are schematic process diagrams relating to the first manufacturing method of the image plane conversion element according to the embodiment of the present invention. Hereinafter, it demonstrates along a process.

“Step 1” (see FIG. 14A)
It is arranged on the exit end side of the image plane conversion element 300 (see FIG. 14D), and is attached to a thin substrate 303 such as glass or plastic that supports the light transmission tube formed in the process described later, in the subsequent process. A support substrate 305 (for example, a Si substrate or a ceramic plate having a Si thin film layer formed by plasma CVD) for maintaining the flatness of the substrate 303 is bonded and fixed. Note that anodic bonding is preferable for bonding the Si substrate. An adhesive may be used.

“Step 2” (see FIG. 14B)
After cleaning and drying the surface of a substrate 303 (for example, a Pyrex (registered trademark) glass or the like, hereinafter referred to as a glass substrate) bonded to the Si substrate 305 as a support substrate, a photoresist 307 is placed on the glass substrate 303 in a predetermined manner. Apply to thickness. For the application, a normal spin coating method or the like is used. As the photoresist 307, for example, the product name SU8 manufactured by Kayaku Microchem Corporation can be used. After applying the photoresist 307, a separately prepared mold 309 is pressed against the surface of the photoresist 307 heated with a heater to create the curved surface shape of the first surface (incident surface) 311 of the image plane conversion element 300. A curved surface shape is created with the mold 309 and the photoresist 307 is pre-baked together. The thickness of the photoresist 307 having a curved surface created by the mold 309 corresponds to the length of the light transmission tube, and is about several microns to several mm.

“Step 3” (see FIG. 14C)
The light transmission tube pattern is exposed and developed on the photoresist 307 using a photomask (not shown) formed so as to correspond to the arrangement of the light receiving elements of the selected image sensor and the light receiving element separation interval. In this way, the image plane conversion element 300 that uses the photoresist 307 portion as a light transmission tube at the time of completion of exposure and development is formed. For exposure, an X-ray exposure method with a deep focal depth or a method of batch exposure using an ultraviolet proximity exposure method, or whether the exposure is divided into areas according to the height from the bottom surface of the glass substrate 303. The exposure method using a stepper exposure method using a reticle prepared according to the area size so that the height difference of the surface of the photoresist film 307 is within the depth of focus of the exposure apparatus, or directly by a laser pattern generator (LPG) A method of exposing by a drawing method is appropriately selected and used.

“Step 4” (see FIG. 14D)
The image plane conversion element 300 is completed by removing the Si substrate 305 as the support substrate. The removal of the Si substrate 305 is performed by using an isotropic dry etching method using XeF 2 gas.

  The glass substrate 303 that supports the photoresist 307 is etched by anisotropic dry etching to a thickness in the middle of the glass substrate 303 using the photoresist 307 as a mask, and the light receiving element and the end surface (second surface) 313 of the light transmission tube 307 are brought closer to each other. By forming in this way, it is possible to suppress the spread of light emitted from the end face 313 of the light transmission tube 307 toward the light receiving element.

  In this manner, the image plane conversion element 300 is completed by the first manufacturing method. Thereafter, as shown in FIG. 2, the light receiving element and the emission end face 313 of the light transmission tube 307 are aligned in a predetermined imaging element. In addition, in order to obtain the workability in aligning the light receiving element and the light transmission tube 307 and the strength of the image plane conversion element 300, a frame portion 600 as shown in FIG. It is desirable to form in the part. In addition, after the alignment between the light receiving element and the light transmission tube 307 is completed, the imaging element may be configured to be fixed and integrated with an adhesive or the like.

(Second manufacturing method)
FIGS. 15A to 15G are schematic process diagrams relating to the second manufacturing method of the image plane conversion element according to the embodiment of the present invention. Hereinafter, it demonstrates along a process. In addition, the same code | symbol is attached | subjected and demonstrated to the member similar to a 1st manufacturing method.

“Step 1” (see FIG. 15A)
A resin member 320 having a flat surface on the imaging element side and a curved surface 311 corresponding to the curvature of field aberration of the imaging optical system is formed by injection molding or the like.

“Step 2” (see FIG. 15B)
The plane of the molded resin member 320 on the imaging element side is bonded to a thin glass substrate 303 (for example, a thickness of about several tens of microns). Note that a transparent film (eg, SiO 2 film) having a thickness of several microns to several tens of microns may be formed on the plane of the molded resin member 320 on the imaging element side by vapor deposition or sputtering to form the substrate 303. .

“Step 3” (see FIG. 15C)
A mask material 322 for etching the resin member 320 (for example, an oxide film such as a SiO2 film, a nitride film such as SiN4) is deposited or sputtered on the surface of the resin member 320 by a thickness of 0.3 to 3.0 microns. Then, a film is formed. The thickness of the SiO 2 film 322 to be formed is determined by the thickness of the resin member 320 to be etched.

“Step 4” (see FIG. 15D)
A photoresist 307 is applied to a predetermined thickness on the SiO2 film 322 as a mask material and pre-baked. Thereafter, exposure is performed using a mask on which a pattern corresponding to the light receiving element of the selected image sensor is formed, and development is performed. As a result, the photoresist 307 remains in a portion corresponding to the light receiving element, and a photoresist pattern 307 is formed by removing the photoresist 307 in the element separation interval for separating the light receiving elements. In addition, the exposure is a method of performing batch exposure using an X-ray exposure method having a deep focal depth or an ultraviolet proximity exposure method, or depending on the height from the bottom surface of the glass substrate 303 attached to the resin member 320. Dividing the area and exposing using a stepper exposure method using a reticle prepared according to the area size so that the height difference of the surface of the photoresist film 307 in the area is within the depth of focus of the exposure apparatus, or A method of exposing by a direct drawing method using a laser pattern generator (LPG) is appropriately selected and used.

“Step 5” (see FIG. 15E)
The SiO2 film 322 is etched using the photoresist 307 as a mask by using a dry etching method such as a reactive ion etching (RIE) method. Thus, the remaining etching layer of the photoresist 307 and the SiO 2 film 322 remain as a mask for the next process in place of the photoresist 307.

“Step 6” (see FIG. 15F)
The remaining resin layer 320 of the photoresist 307 and the SiO2 film 322 are used as a mask to etch the resin member 320 therebelow. The etching uses an anisotropic dry etching method using oxygen gas, and the resin member 320 is etched almost vertically to form the rod-shaped resin member 320. This rod-shaped resin member 320 serves as a light transmission tube (described with the same reference numeral 320). At this time, the lower glass substrate 303 functions as an etching stopper, and functions as a support member 303 that supports the light transmission tube 320 after the etching is completed.

“Step 7” (see FIG. 15G)
The lower glass substrate 303 is etched to an intermediate thickness using the resin member 320 as a light transmission tube as a mask. By this etching, the light transmission tube 320 is formed up to the lower glass substrate 303 and functions as the light transmission tube 320 including the resin member 320 and the glass substrate 303. As a result, the emission end face 313 on the light receiving element side of the light transmission tube 320 can be brought close to the light receiving element, and the spread of the light emitted from the emission end face 313 in the glass substrate 303 can be suppressed. Since the SiO 2 film 322 remaining on the surface of the resin member 320 is etched together when the glass substrate 303 is etched, the SiO 2 film 322 does not remain on the surface of the resin member 320 that is the light transmission tube 320. Note that there is no problem even if the SiO 2 film 322 is transparent and remains on the surface of the resin member 320.

  In this way, the image plane conversion element 330 is completed by the second manufacturing method. Thereafter, as shown in FIG. 2, the light receiving element and the emission end face 313 of the light transmission tube 320 are aligned in a predetermined imaging element. In addition, in order to obtain the workability at the time of alignment between the light receiving element and the light transmission tube 320 and the strength of the image plane conversion element, a frame portion 600 as shown in FIG. It is preferable to form them in the same manner. It should be noted that after the alignment between the light receiving element and the light transmission tube 320 is completed, an image pickup element that is fixed and integrated with an adhesive or the like may be configured.

(Third production method)
FIGS. 16A to 16J are schematic process diagrams relating to the third method of manufacturing the image plane conversion element according to the embodiment of the present invention. The third manufacturing method aims to improve mass productivity. Hereinafter, it demonstrates along a process. In addition, the same code | symbol is attached | subjected and demonstrated to the member similar to the 1st, 2nd manufacturing method.

“Step 1” (see FIG. 16A)
On a support substrate 350 made of glass, quartz, plastic, or the like, a conductive film 351 (for example, an Au / Cr film) having a thickness of about 1 micron is formed by vapor deposition or sputtering. This conductive film 351 will be an electrode in a later electroplating process.

“Step 2” (see FIG. 16B)
The resin member 320 having a curved surface 311 corresponding to the field curvature aberration of the imaging optical system is thinned in advance, and the plane on the imaging element side of the resin member 320 is thin. It adheres on the conductive film 351 through a UV adhesive or the like.

“Step 3” (see FIG. 16C)
A SiO2 film 322 serving as a mask material when etching the resin member 320 is deposited or sputtered to a thickness of 0.3 to 3.0 microns on the surface of the resin member 320. The thickness of the SiO 2 film 322 to be formed is determined by the thickness of the resin member 320 to be etched.

“Step 4” (see FIG. 16D)
A photoresist 307 is applied to a predetermined thickness on the SiO2 film 322 serving as a mask material and pre-baked. Thereafter, exposure is performed using a mask on which a pattern corresponding to the light receiving element of the selected image sensor is formed, and development is performed. As a result, the photoresist 307 remains in a portion corresponding to the light receiving element, and a photoresist pattern 307 is formed by removing the photoresist 307 in the element separation interval for separating the light receiving elements. For exposure, an X-ray exposure method with a deep focal depth or a method of batch exposure using an ultraviolet proximity exposure method, or whether or not the area is divided according to the height from the bottom surface of the glass substrate 350. Exposure method using a stepper exposure method using a reticle prepared according to the area size so that the difference in height of the photoresist film surface is within the depth of focus of the exposure apparatus, or a laser pattern generator (LPG) direct writing method The method of exposing with the above is appropriately selected and used.

“Step 5” (see FIG. 16E)
The SiO2 film 322 is etched using the photoresist 307 as a mask by using a dry etching method such as a reactive ion etching (RIE) method. After the SiO 2 film 322 is etched, the remaining photoresist film 307 is removed. Thus, the SiO2 film 322 remains as a mask for the next process in place of the photoresist.

“Step 6” (see FIG. 16F)
The underlying resin member 320 is etched using the SiO 2 film 322 as a mask. For the etching, an anisotropic dry etching method using oxygen gas is used to etch the resin member 320 to form the rod-shaped resin member 320. This rod-shaped resin member 320 serves as a light transmission tube (described with the same reference numeral 320). At this time, the lower conductive film 351 functions as an etching stopper, and after the etching, the glass substrate 350 functions as a support member for supporting the substrate during electroplating.

“Step 7” (see FIG. 16G)
A Ni mold 360 is formed by Ni electroplating.

“Step 8” (see FIG. 16H)
The glass substrate 350, the resin member 320 which is a light transmission tube, and the conductive film 351 are removed from the mold 360 by etching or the like, and the Ni electroforming mold 360 is completed.

“Step 9” (see FIG. 16I)
The Ni electroforming mold 360 is filled with a UV curable resin, a thermoplastic resin, or the like 370, and the thin glass substrate 371 serving as a support substrate for the resin is covered and UV cured or thermally cured to form a light transmission tube (same reference numeral). 370) and the image plane conversion element 400 is molded. Thereafter, the image plane conversion element 400 is separated from the mold 360. By repeating this process, the same image plane conversion element 400 can be easily manufactured. The image plane conversion element 400 may be molded using an injection molding method using a Ni electroforming mold 360. When the injection molding method is used, a thin resin plate is formed instead of the thin glass plate 371.

“Step 10” (see FIG. 16J)
The lower glass substrate 371 is etched to an intermediate thickness of the thin glass substrate 371 by anisotropic dry etching using the resin member 370 which is a light transmission tube as a mask. By this etching, the light transmission tube 370 is formed up to the lower glass substrate 371, and functions as the light transmission tube 370 including the resin member 370 and the glass substrate 371. As a result, it becomes possible to bring the emission end face 313 on the light receiving element side of the light transmission tube 370 closer to the light receiving element, and to suppress the spread of the light emitted from the emission end face 313 in the glass substrate 371. In addition, when the thin glass substrate 371 which is a support substrate is sufficiently thin (for example, about 10 μm), this step can be omitted.

  In this way, the image plane conversion element 400 is completed by the third manufacturing method. Thereafter, as shown in FIG. 2, the light receiving element and the emission end face 313 of the light transmission tube 370 are aligned in a predetermined imaging element. In addition, in order to obtain the workability and the strength of the image plane conversion element when aligning the light receiving element and the light transmission tube 370, a frame portion 600 as shown in FIG. It is preferable to form them in the same manner. In addition, after the alignment between the light receiving element and the light transmission tube 307 is completed, the imaging element may be configured to be fixed and integrated with an adhesive or the like.

  In addition, the process demonstrated in each manufacturing method mentioned above is a main process, In addition to this, processing processes, such as a general washing process used in manufacture of a semiconductor, a drying process, an element division process, an inspection process, etc. However, the details are not the main part of the manufacturing method, and the explanation is omitted.

  In addition, although a glass substrate is used as a support substrate for the light transmission tube in some processes, a quartz substrate other than glass or a plastic substrate may be used.

  FIG. 17 shows an example of a preferred form of an image sensor having an image plane conversion element according to the present invention. The image plane conversion elements 300, 330, and 400 manufactured by the above-described manufacturing method are disposed on the light receiving surface of the predetermined imaging element 5, and it is necessary to fix the light receiving element and the light transmission tube so as to face each other. At this time, by providing a frame portion 600 as shown in FIG. 17, it is possible to easily perform positioning, bonding, and the like. The frame portion 600 may be removed after the element alignment, or may be used as a fixed frame for the element.

  In addition, the image plane conversion element according to the present invention can be positioned and fixed to the light receiving element of the selected image pickup element, and the image pickup element having the image plane conversion element as a whole can be obtained. As a result, the image plane conversion element and the imaging element can be easily incorporated into the optical system.

  Further, the light receiving element manufacturing process and the light transmitting tube manufacturing process are combined to directly manufacture the light transmitting tube on the light receiving element formed in the light receiving element manufacturing process. It is also possible to form an imaging device.

  As described above, according to the present invention, in an imaging optical system having field curvature aberration, it is disposed between the image plane of the imaging optical system and the image sensor to eliminate the field curvature aberration. It is possible to provide an image plane conversion element that makes it possible to capture an image of an image quality. It is also possible to provide an optical system (imaging optical system) having this image plane conversion element. It is also possible to provide a manufacturing method for manufacturing this image plane conversion element. In addition, it is possible to provide an image sensor in which the image plane conversion element and the image sensor are integrally formed.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

The state which has arrange | positioned the image surface conversion element concerning 1st Embodiment of this invention between the image surface of an imaging optical system and an image pick-up element is shown. FIG. 2 shows an enlarged cross-sectional view of the image plane conversion element and the imaging element in FIG. 1. The light transmission tubes (a) to (c) of various shapes constituting the image plane conversion element are shown. 2 shows an optical system having an image plane conversion element according to a second embodiment of the present invention, where (a) shows a state in which the image plane conversion element is arranged between the image plane and the image pickup element, and (b) shows an optical transmission. The schematic shapes of the tubes are shown respectively. 7 shows an optical system having an image plane conversion element according to a third embodiment of the present invention. 7 shows an optical system having an image plane conversion element according to a fourth embodiment of the present invention. 7 shows an optical system having an image plane conversion element according to a fifth embodiment of the present invention. The 1st Example of the optical system using the image plane conversion element concerning embodiment of this invention is shown, and the schematic block diagram of the optical system containing an image pick-up element is shown. 1 is a schematic configuration diagram of an imaging optical system up to an image plane I. FIG. The curved aberration diagram of the first embodiment is shown, (a) is a curved aberration diagram when the image surface I is a plane, and (b) is imaged on the light receiving surface of the image plane conversion element, that is, a curved image surface. FIG. 4 shows a curved aberration diagram at the time. The 2nd Example of the optical system using the image surface conversion element concerning embodiment of this invention is shown, and the schematic block diagram of the optical system containing an image pick-up element is shown. 1 is a schematic configuration diagram of an imaging optical system up to an image plane I. FIG. The curved aberration diagram of the second embodiment is shown, (a) is a curved aberration diagram when the image plane I is a plane, and (b) is imaged on the light receiving surface of the image plane conversion element, that is, a curved image plane. FIG. 4 shows a curved aberration diagram at the time. The schematic process drawing regarding the 1st manufacturing method of the image plane conversion element concerning embodiment of this invention is shown. The schematic process drawing regarding the 2nd manufacturing method of the image plane conversion element concerning embodiment of this invention is shown. The schematic process drawing regarding the 3rd manufacturing method of the image plane conversion element concerning embodiment of this invention is shown. An example of the preferable form of the image pick-up element which has an image surface conversion element concerning this invention is shown.

Explanation of symbols

1, 11, 21, 31, 41, 101, 300, 330, 400 Image plane conversion element 2 Optical axis 3 Imaging optical system 100, 200 Optical system 5 Imaging element 5a Light receiving element 7, 17, 27, 107 Light transmission tube 30 connecting portion 48 light shielding member 303, 350, 371 (glass) substrate 305 support substrate 307 photoresist, light transmission tube 309, 360 mold 311 curved surface 320 resin member, light transmission tube 370 resin, light transmission tube 600 frame portion

Claims (37)

A method for manufacturing an image plane conversion element, which is disposed between an image plane of an imaging optical system and an image sensor, and forms a plurality of light transmission tubes that respectively face the plurality of light receiving elements of the image sensor so as not to intersect each other. ,
A molding step of molding the surface on the image plane side, which is the first surface of the polymer member on which the light transmission tube is formed, into a curved surface corresponding to the field curvature aberration of the imaging optical system with a mold;
An adhesion step of adhering a plane facing the first surface of the polymer member to a transparent substrate;
The light transmission tube is formed from the polymer member and the transparent substrate, and a second surface, which is an envelope surface of the aggregate of end surfaces of the light transmission tube, is formed substantially parallel to the envelope surface of the light receiving element of the imaging element. And a processing step of forming the second surface in the transparent substrate .   2. The method of manufacturing an image plane conversion element according to claim 1, wherein the polymer member is made of photoresist, plastic, UV curable resin, or thermoplastic resin. The transparent substrate, method of manufacturing the image surface conversion element according to claim 1 or 2, characterized in that a glass, or plastic. The processing step includes the steps of exposing a predetermined light transmission tube pattern, development process, and a manufacturing method of an image plane conversion device according to any one of claims 1 to 3, characterized in that it comprises an etching step.   The method for manufacturing an image plane conversion element according to claim 1, wherein the molding step and the bonding step are performed in the same step. The processing step, the metal film, oxide film, or a manufacturing method of an image plane conversion element according to claim 1, any one of 4, further comprising a nitride film deposition process. In the exposure step, an ultraviolet proximity exposure, an X-ray exposure step, or a region to be exposed is divided into a plurality of regions, and a predetermined reticle is selected according to the height from the bottom of the substrate to the photoresist surface and exposed. The method for manufacturing an image plane conversion element according to claim 4 , further comprising an exposure step by stepper exposure. The method of manufacturing an image plane conversion element according to claim 4 , wherein the etching step includes an isotropic dry etching step or an anisotropic dry etching step. Bonding a support member that supports the transparent substrate in a substantially flat surface;
As the bonding step, a step of applying a photoresist to the transparent substrate;
As the molding step, a step of molding the surface of the photoresist applied to the transparent substrate with the mold,
As the processing step,
Exposing a pattern corresponding to the arrangement of the light receiving elements of the selected image sensor;
Development process;
Etching the substrate using the photoresist obtained in the developing step as a mask;
Peeling the support member;
The method of manufacturing an image plane conversion element according to claim 1, comprising: 10. The image plane conversion element manufacturing process according to claim 9 , wherein the support member is a silicon plate or a ceramic plate or a glass plate having a silicon thin film layer formed by CVD. The method for manufacturing an image plane conversion element according to claim 9, wherein the step of bonding the support member includes anodic bonding. As the molding step, a step of the polymer member, the curved surface first surface corresponds to the curvature of field, and that the second surface is formed into a substantially flat surface,
Bonding the second surface of the polymer member to a transparent substrate as the bonding step;
As the processing step,
Forming a transparent oxide film on the surface of the transparent resin member;
Applying a photoresist on the oxide film;
Exposing a pattern corresponding to the arrangement of the light receiving elements of the selected image sensor;
Development process;
Etching the oxide film;
Etching the transparent resin member using the oxide film as a mask;
Etching the transparent substrate using the transparent member as a mask;
The method of manufacturing an image plane conversion element according to claim 1, comprising: As the step of forming the mold,
Forming a conductive layer on the substrate;
Adhering the second surface side of the resin member on which the first surface is formed into a curved surface corresponding to the curvature of field aberration and the second surface facing the first surface is substantially flat on the conductive layer. When,
Forming an oxide film on the surface of the resin member;
Applying a photoresist on the oxide film;
Exposing a pattern corresponding to the arrangement of the light receiving elements of the selected image sensor;
Development process;
Etching the oxide film;
Etching the resin member using the oxide film as a mask;
Forming Ni mold by performing Ni electroplating using the conductive layer as an electrode;
And a step of removing the resin member and the substrate from the Ni mold,
As the bonding step and the molding step, a step of molding a plurality of the light transmission tube further comprising the polymer member to the Ni mold on the transparent substrate,
As the processing step, an etching step for etching the polymer member and the transparent substrate,
The method of manufacturing an image plane conversion element according to claim 1, comprising: The resin member, the manufacturing method of the image plane conversion element according to claim 13, characterized in that it consists of UV-curable resin, or a thermoplastic resin. The method of manufacturing an image plane conversion element according to claim 13 , wherein the substrate is made of glass or plastic. In the exposure step, an ultraviolet proximity exposure, an X-ray exposure step, or a region to be exposed is divided into a plurality of regions, and a predetermined reticle is selected according to the height from the bottom of the substrate to the photoresist surface and exposed. 14. The method of manufacturing an image plane conversion element according to claim 9 , further comprising an exposure step by stepper exposure. The method for manufacturing an image plane conversion element according to claim 9 , wherein the etching step includes an isotropic dry etching step or an anisotropic dry etching step. It is arranged between the image plane of the imaging optical system and the image sensor, and consists of a plurality of light transmission tubes that are opposed to each other and formed non-intersecting with each other .
The light transmission tube comprises a transparent substrate and a polymer member bonded to the transparent substrate,
A first surface which is molded on the light transmission tube is molded by a die into a curved surface corresponding to the curvature of field in the image plane,
The second surface, which is formed to face the first surface and is the envelope surface of the aggregate of the end surfaces of the light transmission tube, is formed substantially parallel to the envelope surface of the light receiving element of the imaging element,
The second surface is the image surface conversion element characterized Rukoto formed in the transparent substrate. 19. The image plane conversion element according to claim 18 , wherein each end surface of the light transmission tube on the first surface side is formed to be inclined in a direction in which an incident angle of light increases. 19. The image plane conversion element according to claim 18 , wherein each end surface of the light transmission tube on the first surface side is curved in a direction in which the incident angle of light increases. The side edge of the end face neighborhood of the optical transmission tube of the first surface side is the image surface conversion device according to claims 18 to any one of 20, characterized in that it is formed in a concave shape. The image plane conversion element according to any one of claims 18 to 21 , wherein the light transmission tube has an area on the first surface side different from an area on the second surface side. The image plane conversion element according to any one of claims 18 to 22 , wherein the light transmission tube facing the light receiving element is formed only in a central part or only in a peripheral part of the imaging element. . The image plane conversion element according to any one of claims 18 to 23 , further comprising a fixing member that fixes the light transmission tubes on the first surface side to each other. The image plane conversion element according to any one of claims 18 to 24 , wherein a part or all of the side surface portion of the light transmission tube is covered with a light shielding member. The image plane conversion according to any one of claims 18 to 25 , further comprising at least one lens array having lenses disposed in the vicinity of the second surface so as to face the light transmission tube. element. 27. The image plane conversion element according to claim 18 , wherein the light transmission tube is made of an optically transparent member. 28. The image plane conversion element according to claim 27 , wherein the optically transparent member comprises a glass member, a polymer member, an oxide member, or a nitride member. The optical transmission tube, the first surface side, a polymer member, Isure one of claims 18 to 28, wherein the second surface is characterized in that it is supported by the optically transparent member The image plane converting element according to 1. The polymer member, the image plane conversion element according to claim 28 or 29, characterized in that it consists of UV-curable resin. The polymer member, the image plane conversion element according to claim 28 or 29, characterized in that a thermoplastic resin. The polymer member, the image plane conversion element according to claim 28 or 29, characterized in that it consists of photoresist. The light transmission tube is circular, or image surface conversion device as claimed in any one of claims 18 32, characterized in that it has a cross-sectional shape of a polygonal shape. Variation thickness of the light transmission tube is an image plane conversion device as claimed in any one of claims 18 33, characterized in that is within ± 5%. The image plane conversion element according to any one of claims 18 to 34 , wherein a variation in separation interval of the light transmission tube is within ± 5%. An optical system comprising an imaging optical system, an image plane conversion element according to any one of claims 18 to 35 , and an imaging element in order from the object side. 37. An optical system comprising means for moving the first surface of the image plane conversion element according to any one of claims 18 to 36 in a direction perpendicular to the optical axis.

Images