Patent Grant
8542310
This application is a U.S. National Phase Application under 35 USC 371 of International Application PCT/JP2009/062111 filed Jul. 2, 2009.
This application claims the priority of Japanese application 2008-175686 filed Jul. 4, 2008, the entire content of which is hereby incorporated by reference.
The present invention relates to an imaging lens, manufacturing method and imaging unit thereof, and for example, relates to the imaging lens including a wafer level lens suited for mass production, wherein an optical image is formed on the light receiving surface of an image pickup element (e.g., solid image pickup element such as a CCD (Charge Coupled Device) type image sensor and CMOS (Complementary Metal-Oxide Semiconductor) type image sensor).
Various types of optical systems having a wafer level lens have been proposed in the conventional art (for example, Patent Literatures 1 and 2). To manufacture a wafer level lens, a great number of lens portions are manufactured to be arranged on a glass substrate, and the lens having been manufactured is cut off, thereby reducing the production cost. One of the important points is how to arrange the greatest possible number of lens portions, and the lens portions are required to be placed at the closest possible position to one another. In the meantime, in the optical system of an imaging lens and others, such an intervening object as a spacer or lightproof plate need to be placed between the lenses in order to determine the lens distance and to cut off stray light When a wafer level lens is used to manufacturer an imaging lens, assembling and cutting operations are performed with an intervening object sandwiched between glass substrates. If the space between lenses is very small, the intervening object may move during the cutting operation. To prevent this, the space is restricted.
Because of the aforementioned restrictions, when manufacturing the wafer level lens proposed conventionally, it is difficult to find cutting conditions capable of avoiding cracking and chipping, if there is an increase in the type of material. This reduces the range of selecting the cutting conditions. Further, the lens may be distorted by the force applied at the time of cutting, with the result that high performances of the imaging lens cannot be obtained easily.
In view of the problems described above, it is an object of the present invention to provide an imaging lens characterized by easy production and high performances, as well as the manufacturing method and imaging unit thereof.
An object of the present invention can be achieved by the following structures.
1. An imaging lens including at least one set of junction type compound lenses facing each other, each of the junction type compound lenses including a parallel tabular lens substrate and a lens portion formed on at least one of substrate surfaces of the lens substrate,
wherein a space holding portion made of a same material as a material of the lens portion is formed outside an effective aperture of one of the junction type compound lenses facing each other, and
wherein a mating face provided on a surface of the space holding portion is placed in direct contact with a mating face provided at a position facing the mating face of the space holding portion, outside an effective aperture of another facing junction type compound lens among the junction type compound lenses.
2. An imaging lens including at least one set of junction type compound lenses facing each other, each of the junction type compound lenses including a parallel tabular lens substrate and a lens portion formed on at least one of substrate surfaces of the lens substrate,
wherein a space holding portion made of a same material as a material of the lens portion is formed outside effective apertures of the junction type compound lenses facing each other; and
wherein mating faces, each of which is provided on an opposing surface of the space holding portion formed on each of the junction type compound lenses facing each other are placed in direct contact with each other.
3. The imaging lens described in the above item 1 or 2,
wherein the junction type compound lenses facing each other includes a first junction type compound lens located closest to an object, and a second junction type compound lens arranged on an image side of the first junction type compound lens so as to face the first junction type compound lens, and the first junction type compound lens includes, in order of alignment from the object, a first-a lens portion with a convex surface facing the object, a first lens substrate, and a first-b lens portion with a concave surface facing an image, and the second junction type compound lens includes, in order of alignment from the object, a second-a lens portion with a concave surface facing the object and a second lens substrate.
4. The imaging lens described in any one of the above items 1 through 3, further including:
an opaque lightproof sheet between the junction type compound lenses facing each other, outside effective apertures of the junction type compound lenses.
5. The imaging lens described in any one of the above items 1 through 4, wherein a linear recessed portion is formed on a part of the space holding portion.
6. The imaging lens described in any one of the above items 1 through 5, further including:
a warpage preventive function on a substrate surface of the lens substrate, opposite to a substrate surface on which the space holding portion is formed.
7. The imaging lens described in the above item 6,
wherein the warpage preventive function is made of a resin layer
8. The imaging lens described in the above item 6,
wherein the warpage preventive function is made of a thin film.
9. The imaging lens described in any one of the above items 1 through 8,
wherein the space holding portion is formed around the lens portion of a junction type compound lens which has a larger effective aperture among the junction type compound lenses facing each other, by increasing a thickness of a resin layer made of a same material as a material of the lens portion.
10. The imaging lens described in any one of the above items 1 through 9,
wherein a following conditional expression (1) is satisfied.
tl/tb<3.0 (1)
wherein “tl” indicates a thickness from the mating face of the space holding portion to the lens substrate, and “tb” indicates a thickness of the lens substrate.
11. The imaging lens described in any one of the above items 1 through 10, which includes a junction type compound lens located closest to the object, and a following conditional expression (2) is satisfied.
0.5<f1/f<1.3 (2)
wherein “f1” indicates a focal distance of the junction type compound lens closest to the object, and “f” indicates a composite focal distance of an entire imaging lens system.
12. The imaging lens described in the above item 3 consisting of only the first junction type compound lens and the second junction type compound lens,
wherein a following conditional expression (2c) is satisfied.
0.65<f1/f<0.90 (2c)
wherein “f1” indicates a focal distance of a junction type compound lens closest to the object, and “f” indicates a composite focal distance of an entire imaging lens system.
13. The imaging lens described in the above item 12,
14. An imaging unit including the imaging lens of any one described in the above items 1 through 13 and an image pickup element.
15. A method of manufacturing an imaging lens including at least one set of junction type compound lenses facing each other, each of the junction type compound lenses including a parallel tabular lens substrate and a lens portion formed on at least one of substrate surfaces of the lens substrate, the method including the steps of:
forming a space holding portion made of a same material as a material of the lens portion outside an effective aperture of one of the junction type compound lenses facing each other; and
bonding to fix the junction type compound lenses facing each other together during assembling, while placing a mating face provided on a surface of the space holding portion in direct contact with a mating face provided at a position facing the mating face of the space holding portion, outside an effective aperture of another facing junction type compound lens among the junction type compound lenses.
16. A method of manufacturing an imaging lens including at least one set of junction type compound lenses facing each other, each of the junction type compound lenses including a parallel tabular lens substrate and a lens portion formed on at least one of substrate surfaces of the lens substrate, the method including the steps of:
forming a space holding portion made of a same material as a material of the lens portion outside effective apertures of both of the junction type compound lenses facing each other; and
bonding to fix the junction type compound lenses facing each other together during assembling, while placing mating faces, each of which is provided on an opposing surface of the space holding portion formed on each of the junction type compound lenses facing each other in direct contact with each other.
According to the present invention, the space between the junction type compound lenses facing each other is held by the space holding portion formed outside the effective aperture of one or both of junction type compound lenses facing each other. The mating face provided on the surface of the space holding portion is placed in direct contact with the mating face provided outside the effective aperture of the other opposite junction type compound lenses at a position facing the mating face of the space holding portion, or the mating faces provided on the opposing surfaces of the space holding portion formed on both of the junction type compound lens facing each other are brought in direct contact with each other, whereby easy forming and manufacturing is ensured, without the thickness of the space holding portion being increased much over the thickness of the effective aperture portion of the lens.
Further, the space holding portion is made of the same material as that of the lens portion. This increases the range of selection of the cutting conditions, and reduces the distortion of the lens shape caused by the force applied in cutting operations, whereby the high performance of the imaging lens is enhanced. Thus, this arrangement provides an imaging lens and imaging unit characterized by both easy production and high performances.
a, 11b and 11c are aberration diagrams in the optical system of the example 1.
a, 13b and 13c are aberration diagrams in the optical system of the example 2.
a, 15b and 15c are aberration diagrams in the optical system of the example 3.
a, 17b and 17c are aberration diagrams in the optical system of the example 4.
a, 19b and 19c are aberration diagrams in the optical system of the example 5.
a, 21b and 21c are aberration diagrams in the optical system of the example 6.
Referring to the drawings, the following describes an imaging lens, imaging unit, and the method of manufacturing the same. The same or equivalent portions among different embodiments will be assigned with the same symbols of reference, and will not be described to avoid duplication.
The imaging lens of the present invention is made of a lamination of two or more junction type compound lenses, and includes one or more sets of the junction type compound lenses so as to face each other. The “junction type compound lens” is defined as the tabular lamination type wafer level lens including a parallel tabular lens substrate and a lens portion formed on at least one of the substrate surfaces of the lens substrate. “Facing each other” refers to arrangement in mutually adjacent positions. The lens substrate and lens portion assumed in this case are made of different materials. The lens substrate is made of glass, while the lens portion is made of resin. If required, the same single material can be used.
The major point of the imaging lens, imaging unit, and the method of manufacturing the same in the present invention is found in that easy production by the wafer level and high performances of the imaging lens including the junction type compound lens can be ensured by eliminating the spacer member having been required in the conventional technique. A space holding portion made of the same material as that of the lens portion is formed outside the effective aperture of at least one of the junction type compound lenses facing each other, and the spacer function is implemented by direct contact between the mating face arranged on the surface of the space holding portion and that arranged on the other junction type compound lens at the position opposite to the space holding portion. Alternatively, it is also possible to arrange such a configuration that a space holding portion made of the material layer of the same material as that of the lens portion is provided respectively outside the effective aperture of two laminated junction type compound lenses. The mating faces on the surfaces of respective space holding portions are brought in direct contact to determine the space between lenses, whereby the space function is implemented. It is also possible to adopt such a structure that, to determine the space in the direction of optical axis for another junction type compound lens or other optical element located adjacent to the object side or image side of the junction type compound lens, the space holding portion made of the same material as that of the lens portion is arranged outside the effective aperture of the lens portion, whereby the spacer function is implemented.
The effective aperture is defined as the maximum diameter of the imaging lens that allows passage of the group of beams contributing to the formation of an image on the final image surface. When an image pickup element is present on the final image surface, the effective aperture denotes the diameter that allows the passage of the group of beams contributing to the formation of an image with the maximum image height on the image pickup element. The “material layer” refers to the resin layer formed of the same material as that of the lens portion, around the lens portion. Of the material layer, the portion used to hold the space in the direction of optical axis of the lens is called the “space holding portion”. “Direct contact” also includes the contact wherein a bonding layer is used between the mating faces.
In the aforementioned structure, the space between junction type compound lenses facing each other or the space between the junction type compound lens and another optical element is held by the space holding portion formed outside the effective aperture of one or both of the junction type compound lenses facing each other. Easy formation, without the thickness of the space holding portion being much increased over the thickness of the effective aperture of the lens, is ensured by direct contact between the mating face provided on the surface of the space holding portion and the mating face provided on the other opposite junction type compound lens at a position opposite to the mating face of the space holding portion outside the effective aperture, or by direct contact between the mating faces on the mutually opposing surfaces of the space holding portions formed on both junction type compound lenses facing each other. Accordingly, easy production is ensured.
Since the space holding portion is made of the same material as that of the lens portion, the range of selecting the cutting conditions is expanded, and the distortion in the shape of the lens caused by the cutting force is reduced, with the result that performances of the imaging lens are enhanced. This arrangement provides an imaging lens characterized by easier production and higher performances. This permits production of a high-performance imaging unit, by which the image of a subject is optically captured by a combination of the imaging lens and image pickup element and is outputted in the form of an electric signal. The following describes the details of this invention with reference to specific examples.
Similarly to the imaging lens LN of
The first junction type compound lens C1 and second junction type compound lens C2 are fixed in position by bonding the mating face S1 and mating face S2. For the second junction type compound lens C2 and third junction type compound lens C3, the air space is defined by the space holding portion SP formed outside the effective aperture. The imaging lens LN containing the first through third junction type compound lenses C1 through C3 can be structured by cutting at position Q of the mating face S1 and mating face S2. A commonly used adhesive (e.g., UV curable adhesive) can be used for bonding between the mating face S1 and mating face S2. For bonding the mating face S1 and mating face S2, the materials used to form the mating face S1 and mating face S2 are preferably the same as each other. If the mating face S1 and mating face S2 are made of the same material, it is only required to select one type of adhesive conforming to that material.
As described above, the imaging lens LN of
In the imaging lens LN of
If a spacer member S is used as shown in
As shown in the first embodiment (
In the aforementioned first embodiment (
In the first embodiment (
The sixth embodiment (
In the first embodiment (
For example, a dry film resist or commonly used adhesive sheet having a lightproof function can be use as the opaque sheet SD. The opaque sheet SD is preferably adhered closely to the material layer made of resin. If fixing stability can be maintained between the first junction type compound lens C1 and second junction type compound lens C2, the sheet SD need not be adhered closely to the material layer. Here, application of a plurality offing-like sheets is assumed. However, an opaque sheet with a plurality of openings can be applied. In this case, a hole for allowing direct contact of the mating faces S1 and S2 need also be provided. The lightproof portion of the opaque sheet SD is required only to cover the required range outside the effective aperture. However, more preferably, the lightproof portion covers the range outside the effective aperture up to be close to the effective aperture. It should be noted that the structure of the aforementioned opaque lightproof sheet SD is also applicable when the space holding portion SP is used to define the space in the direction of optical axis AX for the optical element other than the junction type compound lens located adjacent to each other on the object or image side of the junction type compound lens C2. To put it another way, the opaque lightproof sheet SD can be placed outside the effective aperture between the junction type compound lens and other optical elements located adjacent to each other on the object or image side of the junction type compound lens.
According to the aforementioned first through seventh embodiments, in both the first junction type compound lens C1 and second junction type compound lens C2, lens portions L1A, L1B; L2A, L2B are formed on both the substrate surfaces of each of the lens substrate L1P and lens substrate L2P. The aforementioned structure of using the space holding portion SP and others to implement the spacer function is applicable to the imaging lens including the junction type compound lens where the lens portion is formed only on one of the substrate surfaces of the lens substrate. However, if the lens portion is formed only on one side of the lens substrate, the lens substrate will be bent by the curing of the resin material constituting the lens portion. This may cause the entire junction type compound lens to be warped. On the wafer level, this has a serious impact on the performance. To solve this problem, for the lens substrate, the warpage preventive function is preferably provided on the substrate surface on the side opposite of the substrate surface on the side where the lens portion is formed. The following describes the warpage preventive function with reference to the cross sectional view of the major section in
In the junction type compound lens CB of the eighth embodiment, as shown in
The thickness of the space holding portion constituting the mating face preferably meets the following conditional expression (1):
tl/tb<3.0 (1)
wherein “tl” indicates the thickness from the mating face to the lens substrate, and “tb” denotes the thickness of the lens substrate.
The conditional expression (1) defines the preferred range of conditions for the thickness of the space holding portion with respect to the thickness of the lens substrate. When conditional expression (1) is met, costs can be reduced without the entire optical length being affected, even if the warpage preventive function on the rear surface of the lens substrate is added. If the space holding portion constituting the mating face is thick, a thick resin layer will have to be provided on the opposite side as well. This will require expansion of the space on the side opposite the mating face, with the result that the overall optical length will be increased. Further, much resin will have to be used, and a cost increase will result. Nan attempt is made to prevent warpage by coating, the coated layer will be thick. This will also increase the cost.
The conditional expression (1a) is preferably met, and the conditional expression (1b) is more preferably met:
tl/tb<2.0 (1a)
tl/tb<1.5 (1b)
In the range of conditions defined by the conditional expression (1), these conditional expressions (1a) and (1b) define a still more preferable range of conditions, based on the aforementioned viewpoint. The aforementioned effects will be further increased if the conditional expression (1a) is preferably met, or if the conditional expression (1b) is further preferably met.
For the overall length of the imaging lens, the imaging lens includes the junction type compound lens closest to the object, preferably meets the following conditional expression (2):
0.5<f1/f<1.3 (2)
wherein “f1” indicates the focal distance of the junction type compound lens closest to the object, and “f” denotes the composite focal distance of the entire imaging lens system.
The conditional expression (2) defines the preferred range of conditions in the sense of reducing the overall length of the imaging lens (i.e., to reduce a space between the junction type compound lenses). To reduce the overall length of the lens, it is most effective to adjust the power of the junction type compound lens closest to the object so as to meet the conditional expression (2). Further, reduction of the space between the junction type compound lenses will result in a reduction of the height from the substrate surface to the mating face (i.e., to reduce the thickness of the space holding portion). An excessive increase in the power of the junction type compound lens closest to the object or in the thickness of the lens portion is not caused by exceeding the lower limit of the conditional expression (2). The entire length of the lens portion can be reduced by keeping the value below the upper limit of the conditional expression (2). As a result, the space between the junction type compound lenses can be reduced.
The following conditional expression (2a) is more preferably met:
0.6<f1/f<1.1 (2a)
This conditional expression (2a) defines a more preferred range of conditions based on the aforementioned viewpoint in the range of conditions defined by the aforementioned conditional expression (2). When the conditional expression (2a) is preferably met, the aforementioned effects will be fluffier increased.
Further, the imaging lens is made of two junction type compound lenses, i.e., a first junction type compound lens located closest to the object and a second junction type compound lens facing the first junction type compound lens and located on the image side thereof. The first junction type compound lens is provide with a first lens portion having a convex facing the object, and a first lens substrate and a second lens portion having a concave facing the image, in order of alignment from the object. The second junction type compound lens is provided with a third lens portion having a concave facing the object and a second lens substrate, in order of alignment from the object. It is preferred that the internal lens portions both have concave surfaces, if the mating faces of the space holding portion facing each other are bonded. In this case, the imaging lens preferably meets the following conditional expression (2c):
0.65<f1/f<0.90 (2c)
When the conditional expression (2c) is met, the overall length of the imaging lens can be reduced with the performances of the imaging lens being maintained. This arrangement suppresses the aberration resulting from the power of the first junction type compound lens C1 being excessively increased when the value is kept below the upper limit of the conditional expression (2c). When the value is kept over the lower limit of the conditional expression (2c), the first junction type compound lens will have an increased power. This allows the overall length of the imaging lens to be reduced, and preferably permits the space to be reduced between the junction type compound lenses.
If the aforementioned conditional expression (2c) has been met, the space between the junction type compound lenses can be reduced. It is further preferred for the junction type compound lens to meet the conditional expression (3):
0.10<d/f<0.35 (3)
wherein “d” indicates the distance between the lens substrates of two junction type compound lenses, and “f” denotes the composite focal distance of the entire imaging lens system.
The resin thickness from the substrate surface to the mating face can be optimized by meeting the conditional expression (3). If the value is kept below the upper limit of the conditional expression (3), the space between the substrates is reduced and the height to the mating face is also reduced, so that the thickness of the space holding portion can be reduced. When the overall length of the imaging lens is to be reduced, the lens closest to the object will be heavily convexed. To correct the aberration produced on the heavily convexed surface, a heavily concaved surface is required. If the value is increased over the lower limit of the conditional expression (3), the space between substrates will not be too small, and the degree of freedom in the shape of the lens portion of the junction type compound lens can be ensured. Thus, a heavily concave surface can be obtained. Even when the overall length is to be reduced, aberrations can be effectively corrected.
Under the optimum design conditions for an imaging lens, the overall optical length is 1.0 mm or more without exceeding 10 mm, or is 2.0 mm or more without exceeding 5.0 mm.
The following describes specific examples of the imaging lens. In each of the examples, the aperture stop S is formed by applying chromium vapor deposition directly to the surface of the lens substrate. Thus, the aperture stop S is not an intervening object mentioned in the description of BACKGROUND. Accordingly, the lens portion will not be misaligned at the aperture stop S at the time of cutting.
As shown in
In this structure, the light having entered from the object side passes through the first-a lens portion L1a, aperture stop S, first lens substrate LS1, first-b lens portion L1b, second-a lens portion L2a, second lens substrate LS2, second-b lens portion L2b and parallel flat plate PT in that order along the optical axis. The optical image of an object is formed on the light-receiving surface IM of the image pickup element.
The following shows the construction data on each lens in the optical system of the example 1. The numeral “ri” accompanied for each lens surface (wherein “i”=1, 2, 3, . . . ) indicates the “i-th” lens surface as counted from the object side (wherein the jointed surface of the lens is counted as constituting one surface). The surface where “ri” is affixed with “*” is aspherical. Both surfaces of the parallel flat plate PT are also counted as one surface. The aperture stop S has a negligibly small thickness, and therefore, is handled as constituting a part of the surface of the glass substrate where the aperture stop S is formed. This method of handling and the meaning of the symbols are applicable also to the examples 2 through 6 to be described later (
In the aforementioned surface data, “r” is a curvature radius (in units of “mm”); “d” is the distance between lens surfaces on the optical axis in the focused state at infinity, i.e., the distance of the surface on the axis (in units of “mm”); “nd” is a refractive index for the d-line of each lens (having a wavelength of 587.56 nm); and “νd” is an Abbe's number. Further, the effective radius (in units of “mm”) on each surface is shown at the end of the surface data. Both surfaces of the parallel flat plate FT PT are flat and their curvature radius “r” is ∞ (infinite).
The aforementioned aspherical surface data indicates the quadric surface parameter (conical coefficient K) and the aspherical surface coefficient “Ai” (wherein i=4, 6, 8, 10, 12, 14, 16, 18, and 20) of the aspherical surface where the numeral “i” is affixed with “*” in the surface data. The aspherical surface coefficient “Ai” without description indicates 0 (zero). The aspherical shape of the optical surface is defined by the following formula using the local coordinate axis system (x, y, z), wherein the vertex of the surface is an origin, and the direction from the object toward the image pickup element is the positive direction of the z-axis:
z(h)=ch2/[1+√{1−(1+K)c2h2}]+ΣAi·hi
wherein z (h) is the displacement in the z-axis direction at height “h” (reference for the vertex of the surface); h is the height perpendicular to the z-axis (h2=x2+y2); cis a paraxial curvature (=1/curvature radius); Ai is an i-th order aspherical surface coefficient; and K is a quadric surface parameter (conical coefficient). In the aforementioned aspherical surface data, “En” denotes “10 to the n-th power”. For example, “E+01” denotes “10 to the 1st power”. “E−03” denotes “10 to the −3rd power”.
a, 11b and 11c show the aberrations in the optical system of the example 1 based on the aforementioned lens arrangement and configuration.
As shown in
In this structure, the light having entered from the object side passes through the first-a lens portion L1a, first lens substrate LS1, aperture stop S, first-b lens portion L1b, second-a lens portion L2a, second lens substrate LS2, second-b lens portion L2b, and parallel flat plate PT in that order along the optical axis. The optical image of an object is formed on the light-receiving surface IM of the image pickup element.
The following shows the construction data on each lens in the optical system of the example 2.
a, 13b and 13c show various forms of aberrations in the optical system of the example 2 where the lens layout and configuration are as described above.
The optical system of the example 3 is composed of the first junction type compound lens BK1 and second junction type compound lens BK2 in that order from the object to the image side, as shown in
In this structure, the light having entered from the object side passes through the first-a lens portion L1a, aperture stop S, first lens substrate LS1, first-b lens portion L1b, second-a lens portion L2a, second lens substrate LS2, and second-b lens portion L2b in that order along the optical axis. The optical image of an object is formed on the light-receiving surface IM of the image pickup element.
The following shows the construction data on each lens in the optical system of the example 3.
a, 15b and 15c show various forms of aberrations in the optical system of the example 3 where the lens layout and configuration are as described above.
The optical system of the example 4 is composed of the first junction type compound lens BK1 and second junction type compound lens BK2 in that order from the object to the image side, as shown in
In this structure, the light having entered from the object side passes through the first-a lens portion L1a, first lens substrate LS1, aperture stop S, first-b lens portion L1b, second-a lens portion L2a, second lens substrate LS2, second-b lens portion L2b, and parallel flat plate PT in that order along the optical axis. The optical image of an object is formed on the light-receiving surface IM of the image pickup element.
The following shows the construction data on each lens in the optical system of the example 4.
a, 17b and 17c show various forms of aberrations in the optical system of the example 4 where the lens layout and configuration are as described above.
The optical system of the example is composed of the first junction type compound lens BK1, second junction type compound lens BK2, and the third junction type compound lens BK3 in that order from the object to the image side, as shown in
In this structure, the light having entered from the object side passes through the first-a lens portion L1a, aperture stop S, first lens substrate LS1, first-b lens portion L1b, second-a lens portion L2a, second lens substrate LS2, second-b lens portion L2b, third-a lens portion L3a, third lens substrate LS3, third-b lens portion L3b, and parallel flat plate PT in that order along the optical axis. The optical image of an object is formed on the light-receiving surface IM of the image pickup element.
The following shows the construction data on each lens in the optical system of the example 5.
a, 19b and 19c show various forms of aberrations in the optical system of the example 5 where the lens layout and configuration are as described above.
The optical system of the example 6 is composed of the first junction type compound lens BK1, second junction type compound lens BK2, and the third junction type compound lens BK3 in that order from the object to the image side, as shown in
In this structure, the light having entered from the object side passes through the first-a lens portion L1a, aperture stop S, first lens substrate LS1, first-b lens portion L1b, second-a lens portion L2a, second lens substrate LS2, third-a lens portion L3a, third lens substrate LS3, third-b lens portion L3b, and parallel flat plate PT in that order along the optical axis. The optical image of an object is formed on the light-receiving surface IM of the image pickup element.
The following shows the construction data on each lens in the optical system of the example 6.
a, 21b and 21c show various forms of aberrations in the optical system of the example 6 where the lens layout and configuration are as described above.
As described above, according to the present invention, the space between the junction type compound lenses facing each other or the space between the junction type compound lens and other optical element is held by the space holding portion formed outside the effective aperture of one or both of the junction type compound lenses facing each other. Easy formation, without the thickness of the space holding portion being much increased over the thickness at the effective aperture portion of the lens, is ensured by direct contact between the mating face provided on the surface of the space holding portion and the mating face provided opposite the mating face of the space holding portion, outside the effective aperture of the other opposite junction type compound lens, or by direct contact between the mating faces on the mutually opposing surfaces of the space holding portions formed on both junction type compound lenses facing each other. This structure ensures easy production.
Since the space holding portion is made of the same material as that of the lens portion, the range of selecting the cutting conditions is expanded, and the distortion in the shape of the lens caused by the cutting force is reduced, with the result that performances of the imaging lens are enhanced. This arrangement provides an imaging lens and imaging unit characterized by easier production and higher performances.
The detailed configuration and operations of the components constituting the imaging lens, manufacturing method and imaging unit thereof can be embodied with appropriate modification, without departing from the technological spirit and scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-175686 | Jul 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2009/062111 | 7/2/2009 | WO | 00 | 12/23/2010 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2010/001955 | 1/7/2010 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 8049806 | Feldman et al. | Nov 2011 | B2 |
| 20070242370 | Fukuta et al. | Oct 2007 | A1 |
| 20090225215 | Korenaga et al. | Sep 2009 | A1 |
| 20120206639 | Matsui et al. | Aug 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| 2884235 | Mar 2007 | CN |
| 101055345 | Oct 2007 | CN |
| 63-082401 | Apr 1988 | JP |
| 1-177007 | Jul 1989 | JP |
| 11-211902 | Aug 1999 | JP |
| 2002-90621 | Mar 2002 | JP |
| 2003-4906 | Jan 2003 | JP |
| 2003-329808 | Nov 2003 | JP |
| 2005-195733 | Jul 2005 | JP |
| 2006-64758 | Mar 2006 | JP |
| 3929479 | Jun 2007 | JP |
| 2007-524243 | Aug 2007 | JP |
| 2007-233320 | Sep 2007 | JP |
| 2007-286153 | Nov 2007 | JP |
| 2008-508545 | Mar 2008 | JP |
| WO 2005083789 | Sep 2005 | WO |
| WO 2006010622 | Feb 2006 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20110102661 A1 | May 2011 | US |
