JP2008268876A - Imaging lens, manufacturing method therefor, and compound lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging lens capable of suppressing reduction in resolving power due to transmission decentration of lenses, to provide a manufacturing method of the imaging lens, and to provide a compound lens. <P>SOLUTION: In the imaging lens 1, one compound lens 2 and two single lenses 5 and 6 are arranged in a lens barrel 7. On the light output side of the lens barrel 7, a filter 8 is arranged with an interval separating from the lens barrel 7. With a further distance from the filter 8, an imaging element 9 is arranged. In the compound lens 2, a resin lens 4 is bonded to a base member lens 3, having an output surface center 44b of the resin lens 4 displaced by a prescribed amount relative to an output surface center 33b of the base member lens 3 so that a transmission decentration amount attributed to the base member lens 3, excluding the resin lens 4, and the single lenses 5 and 6 is canceled by a transmission biased amount by the resin lens 4, when the lens system is taken as a whole. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photographic lens, a manufacturing method thereof, and a composite lens, and more particularly to a photographic lens having a plurality of lenses including a composite lens, a manufacturing method of such a photographic lens, and a composite lens.

  In recent years, there has been a demand for downsizing, weight reduction, and cost reduction of photographing lenses such as mobile phone cameras or digital cameras. In this type of photographic lens, for example, as shown in FIG. 40, a plurality of lenses 103, 105, 106 are arranged in a lens barrel 107. On the light emission side of the lens barrel 107, a filter 108 and an image sensor 109 are sequentially arranged.

In particular, in a photographing lens of a mobile phone camera, a plastic lens is adopted as proposed in Patent Document 1, for example, in order to reduce the weight and cost. In addition, in order to shorten the overall length of the mobile phone camera and increase the resolution, a compound lens in which a resin lens is bonded to the surface of a plastic lens is also being studied.
Japanese Patent No. 3594088

  However, the conventional photographing lens has the following problems. Generally, a plastic lens is formed by a molding method or the like. In a plastic lens formed by a molding method or the like, the center of the lens surface on the incident side of the plastic lens (center of the incident surface) is aligned with a predetermined axis of the plastic lens taken out from the mold, for example, the central axis with respect to the outer shape (outer shape central axis). ) And the center of the lens surface on the exit side (the center of the exit surface) are not necessarily coincident (positioned on the outer shape central axis).

  Therefore, in a state where the lenses 103, 105, and 106 are incorporated in the lens barrel 107, line segments 121, 122, and 123 that connect the centers of the incident surfaces and the exit surfaces of the lenses 103, 105, and 106 are The lens system is eccentric with respect to the barrel central axis 112, and the entire lens system may be transmitted eccentrically (line segment 124). As a result, the light that has passed through the lenses 103, 105, and 106 does not form a good image on the image sensor 109, and the resolution may be reduced or half of the image may be blurred.

  The line segment 121 is a line segment connecting the incident surface center 133a of the incident surface 103a of the lens 103 and the output surface center 133b of the output surface 103b, and the line segment 122 is the center of the incident surface of the incident surface 105a of the lens 105. 144a and the exit surface center 144b of the exit surface 105b, and the segment 123 is a line segment connecting the entrance surface center 155a of the entrance surface 106a of the lens 106 and the exit surface center 155b of the exit surface 106b. .

  The present invention has been made to solve the above-mentioned problems, and one object is to provide a photographing lens in which a decrease in resolution due to transmission eccentricity of the lens is suppressed, and another object is to do so. Another objective is to provide a composite lens suitable for such a photographic lens and its manufacturing method.

The photographic lens according to the present invention is a photographic lens including a plurality of lenses, and includes a first lens and a second lens. In the first lens, a resin lens is bonded to a base lens. The second lens is disposed with a predetermined positional relationship with the first lens. In the first lens, the transmission decentering amount caused by the base lens and the second lens before the resin lens is bonded is determined as the entire lens system of the first lens and the second lens by the transmission decentering amount by the resin lens. The resin lens is bonded to the base lens by shifting the position of the center of the exit surface of the resin lens and the center of the exit surface of the base lens by a predetermined amount so that they are canceled out.

  According to this configuration, the transmission eccentricity caused by the base lens and the second lens before the resin lens is joined is positioned by a predetermined amount between the center of the exit surface of the resin lens and the center of the exit surface of the base lens. The entire lens system of the first lens and the second lens is canceled by the amount of transmission eccentricity caused by the resin lens that is shifted and joined to the base lens. Thereby, it can suppress that the resolving power of a photographic lens falls.

  In order to confirm the amount of displacement, the resin lens is preferably provided with a predetermined first marker centered on the exit surface center, and the base lens is centered on the exit surface center. It is preferable that a predetermined second marker is formed.

  More specifically, the first marker and the second marker are preferably annular convex portions or concave portions.

  A method for manufacturing a photographic lens according to the present invention is a method for manufacturing a photographic lens having at least a first lens in which a resin lens is bonded to a base lens and a second lens, and includes the following steps. . Resin so that the transmission decentering amount caused by the base lens and the second lens before joining the resin lens is canceled by the transmission decentering amount by the resin lens as the entire lens system of the first lens and the second lens A predetermined positional deviation amount between the center of the exit surface of the lens and the center of the exit surface of the base lens is obtained. Based on the obtained positional deviation amount, a first lens is formed by bonding a resin lens to the emission surface of the base lens. The formed first lens and second lens are arranged in a predetermined positional relationship.

  According to this method, the base material before the resin lens is joined by joining the resin lens to the base lens while shifting the position of the exit surface center of the resin lens and the exit surface center of the base lens by a predetermined amount. The transmission decentering amount caused by the lens and the second lens is canceled by the entire lens system of the first lens and the second lens by the transmission decentering amount by the resin lens. Thereby, it can suppress that the resolving power of a photographic lens falls.

  More specifically, in the step of obtaining the amount of positional deviation, the positional deviation between the center of the incident surface and the center of the outgoing surface of each of the base lens and the second lens with reference to the outer central axis of the base lens and the second lens. There is a method for obtaining a predetermined positional deviation amount based on the amount.

  Further, the transmission eccentricity in a state where the base lens and the second lens are arranged on the lens barrel where the first lens and the second lens are arranged is obtained, and the obtained transmission eccentricity is canceled out. There is a method for obtaining a predetermined positional deviation amount.

  More specifically, in order to form the first lens based on the obtained positional deviation amount, the lens holding portion that holds the base lens and the mold that molds the resin lens are relatively aligned in the horizontal direction. It is preferable that the resin lens is bonded to the exit surface of the base lens.

More specifically, as the step of forming the first lens, the step of holding the base lens in a predetermined posture with respect to the lens holding portion, and the lens holding portion and the mold are relatively shifted in the horizontal direction. Later, the process of injecting the resin to be a resin lens into the mold and the base lens held by the lens holding part in contact with the resin while maintaining the relative positional relationship in the horizontal direction And a step of bonding the resin lens to the base lens by curing the resin.

  Alternatively, the step of relatively shifting the lens holding portion and the mold in the horizontal direction and injecting the resin to be a resin lens into the mold, and the step of placing the base lens on the mold and contacting the resin In addition, a step of holding the base lens in the lens holding portion in a predetermined posture and a step of bonding the resin lens to the base lens by curing the resin may be included.

  Further, an ultraviolet curable resin is applied as the resin to be the resin lens, and in the step of forming the first lens, it is preferable to cure the resin by irradiating the resin with ultraviolet rays.

  The compound lens according to the present invention is a compound lens in which a resin lens is bonded to a base lens, and includes the resin lens and the base lens. The resin lens has a first entrance surface and a first exit surface, and a predetermined first marker is formed on one of the first entrance surface and the first exit surface. The base lens has a second entrance surface and a second exit surface, and a resin lens is bonded, and a predetermined second marker is formed on at least one of the second entrance surface and the second exit surface. Yes.

  According to this configuration, since the first marker is formed on the resin lens and the second marker is formed on the base lens, the positional deviation amount between the resin lens and the base lens can be easily confirmed.

  Specifically, the first marker is preferably formed at the center of one surface of the resin lens or centered on the surface center of one surface, and the second marker is formed of the base lens. It is preferable that it is formed around the center of at least one of the surfaces.

  More specifically, the first marker and the second marker are preferably annular convex portions or concave portions.

Embodiment 1
A photographic lens and a manufacturing method thereof according to Embodiment 1 of the present invention will be described. As shown in FIG. 1, in the photographing lens 1, one compound lens 2 and two single lenses 5 and 6 are arranged in a lens barrel 7. On the light emission side of the lens barrel 7, a filter 8 is disposed at a distance from the lens barrel 7, and an imaging element 9 is disposed at a distance from the filter 8.

  The compound lens 2 includes a base lens 3 and a resin lens 4, and the resin lens 4 is bonded to the lens surface on the emission side of the base lens 3. The base lens 3 has a function of condensing light, for example, and the resin lens 4 has a function of reducing achromaticity, spherical aberration, and the like. The single lenses 5 and 6 have a function of reducing various aberrations such as astigmatism. In order to exert these functions, the lens surfaces of the compound lens 2 and the single lenses 5 and 6 are set to a predetermined spherical surface or aspherical surface.

  In the photographing lens 1, as will be described in detail later, the transmission eccentricity due to the base lens 3 before the resin lens 4 is bonded to the base lens 3 and the remaining single lenses 5 and 6 is reduced. After the resin lens 4 is bonded to the base lens 3, the compound lens 2 and the single lenses 5 and 6 are disposed in the lens barrel 7, and the composite lens 2 is combined with the transmission eccentricity by the resin lens 4. The center (outgoing surface center 44b) position of the lens surface (outgoing surface 4b) on the exit side of the resin lens 4 and the exit surface 3b of the base lens 3 so that the entire lens system of the lens 2 and the single lenses 5 and 6 are canceled out. Is shifted by a predetermined amount (see FIG. 17).

  That is, in the resin lens 4, the transmission eccentricity caused by the remaining base lens 3 excluding the resin lens 4 and the single lenses 5 and 6 is canceled by the transmission eccentricity by the resin lens 4 as the entire lens system. Thus, the position of the emission surface center 44b of the resin lens 4 is shifted by a predetermined amount with respect to the emission surface center 33b of the substrate lens 3, and the substrate lens 3 is joined. The transmission eccentricity is the amount of positional deviation from the optical axis at the position where light passes through one lens and forms an image, or the position where light passes through a plurality of lenses (lens modules) and forms an image. The amount of positional deviation from the optical axis.

  Next, an example of a method for manufacturing the above-described photographic lens 1 will be described. First, using an eccentricity measuring instrument, as shown in FIG. 2, the incident on each of the base lens 3 and the single lenses 5 and 6 with reference to the central axis (outer shape central axis 11) with respect to the outer shape of the lens. The amount of positional deviation between the incident surface center 14 of the surface 13 and the exit surface center 16 of the exit surface 15 is measured. Here, the outer shape refers to the outer periphery of the lens. The outline central axis is an axis passing through the center of a circle along the outer periphery of the lens.

This positional deviation amount will be described in more detail. As shown in FIG. 3, consider an XY plane in which the origin O is a point that is orthogonal to the outer shape center axis 11 and intersects the outer shape center axis 11. A position where a straight line passing through the incident surface center 14 and parallel to the outer shape central axis 11 intersects the XY plane is defined as a position 14a, and a position passing through the output surface center 16 and parallel to the outer shape center axis 11 is intersected with the XY plane. Assuming that the position is 16a, the amount of positional deviation between the incident surface center 14 and the outer shape central axis 11 is obtained as the distance between the position 14a and the origin O. Further, the positional deviation amount between the emission surface center 16 and the outer shape central axis 11 is obtained as a distance between the origin O and the position 16a.

  Next, the resin lens is formed on the base material based on the obtained positional deviation amount with respect to the outer shape center axis 11 between the entrance surface center 14 and the exit surface center 16 of each of the base lens 3 and the single lenses 5 and 6. In the state where the lens barrel 7 is disposed together with the single lenses 5 and 6 as the compound lens 2 after being joined to the lens (entire lens system), the transmission eccentricity due to the base lens 3 and the single lenses 5 and 6 is canceled out. As described above, the positional deviation amount T (distance in the XY plane) for shifting the emission surface center 44b of the resin lens 4 with respect to the emission surface center 33b of the base lens 3 is calculated by optical calculation. At this time, the circumferential positions of the compound lens 2 and the single lenses 5 and 6 are also obtained.

  Next, in order to consider a manufacturing error when a resin lens is molded and bonded to the base lens, a reference compound lens is manufactured. First, as shown in FIG. 4 and FIG. 5, for example, a metal mold 20 is formed so that the center axis 22 of the mold 20 for molding the resin lens and the center axis 31 of the lens holding unit 30 for holding the base lens are aligned. The mold 20 is slid with respect to the lens holding unit 30. The mold 20 has a recess 21 into which a predetermined resin to be a resin lens is injected.

  Next, as shown in FIG. 6, the base lens 3 is placed on the mold 20 with the lens surface to which the resin lens is bonded in the base lens 3 facing downward. The base lens 3 is held in a predetermined posture with respect to the lens holder 30 by lowering the lens holder 30 and bringing the tip of the lens holder 30 into contact with the base lens 3.

  Next, as shown in FIG. 7, the lens holding unit 30 is raised while the base lens 3 is held by the lens holding unit 30. Next, an ultraviolet curable resin 40 is injected into the recess 21 of the mold 20. Next, the lens holding unit 30 is lowered to place the base lens 3 on the mold 20, and a predetermined lens surface of the base lens 3 is brought into contact with the resin 40. Next, as shown in FIG. 8, the resin 40 is cured by irradiating with ultraviolet rays. After the resin 40 is cured, the resin lens is taken out from the mold 20 to complete the reference compound lens 200 in which the resin lens 4 is bonded to the base lens 3 as shown in FIG.

  Next, the amount of displacement of the center position of the lens surface of the completed reference compound lens 200 is measured. As shown in FIG. 10, a marker 23 to be transferred to the resin lens is formed in advance in the recess 21 of the mold 20 in which the resin lens is molded. As the marker 23, for example, when forming the recess 21 by grinding, a grinding mark remaining concentrically on the mold can be used, and the center of the concentric grinding mark is the center axis of the mold 20. Is done. Thereby, the marker 4c corresponding to the marker 23 is transferred to the emission surface of the resin lens to be molded, and the center of the marker 4c becomes the emission surface center 44b (see FIG. 12).

  On the other hand, in the base lens, as shown in FIG. 11, the outer peripheral portion of the base lens 3 is formed by a concentrically formed marker provided on a mold (not shown) for molding the base lens. A marker 3c is formed. The center of the concentric marker 23 is the emission surface center 33b of the emission surface 3b of the base lens 3 (see FIG. 12). The markers 4c and 3c may be convex or concave. In particular, the marker 3c formed on the base lens 3 is preferably formed in a region outside the effective diameter of the lens.

In this way, as shown in FIG. 12, in the reference compound lens 200, the positional deviation amount SO (distance) between the emission surface center 33b of the base lens 3 and the emission surface center 44b of the resin lens 4 is measured. In FIG. 12, the displacement amount SO is exaggerated for the sake of explanation.

  Next, an actual positional deviation amount between the lens holding unit 30 and the mold 20 for obtaining the positional deviation amount T is obtained. That is, when the center axis 22 of the mold 20 and the center axis 31 of the lens holding portion 30 are matched, the positional deviation amount SO between the exit surface center 33b of the base lens 3 and the exit surface center 44b of the resin lens 4 is determined. In order to obtain the calculated displacement amount T between the center of the exit surface of the base lens 3 and the center of the exit surface of the resin lens 4, the center axis 22 of the mold 20 and the center of the lens holding unit 30 are actually calculated. A positional shift amount S1 that should be shifted relative to the shaft 31 is obtained.

  Next, a compound lens is manufactured based on the obtained positional deviation amount S1. First, through the same process as the process shown in FIGS. 4 to 7 described above, as shown in FIG. 13, with the central axis 22 of the mold 20 and the central axis 31 of the lens holding part 30 aligned, The base lens 3 is held in a predetermined posture with respect to the lens holding unit 30.

  Next, as shown in FIG. 14, the center axis 22 of the mold 20 is slid relative to the center axis 31 of the lens holding portion 30 by the calculated positional deviation amount S1. Next, an ultraviolet curable resin 40 is injected into the recess 21 of the mold 20. Next, the lens holding unit 30 is lowered to place the base lens 3 on the mold 20, and the emission surface of the base lens 3 is brought into contact with the resin 40. Next, as shown in FIG. 15, the resin 40 is cured by irradiation with ultraviolet rays. After the resin 40 is cured, the resin lens 4 is taken out from the mold 20 to complete the composite lens 2 in which the resin lens 4 is bonded to the base lens 3 as shown in FIG.

  As shown in FIG. 17, in this compound lens 2, the exit surface center 33 b of the base lens 3 and the exit surface center 44 b of the resin lens 4 are formed when the resin lens 2 is molded and joined to the base lens 3. In consideration of the error (positional displacement amount SO), the positional displacement is made by the positional displacement amount S1. The exit surface center 33b of the base lens 3 and the entrance surface center 44a of the resin lens 4 coincide.

  Next, as shown in FIG. 18, the compound lens 2 and the single lenses 5 and 6 are disposed in the lens barrel 7. At this time, the lens is disposed in consideration of the circumferential positions (arrows 80 to 82) of the compound lens 2 and the single lenses 5 and 6, which are obtained when calculating the positional deviation amount T. In this way, as shown in FIG. 19, the taking lens 1 in which the compound lens 2 and the single lenses 5 and 6 are arranged in the lens barrel 7 as a plurality of lenses is completed.

  In this photographic lens 1, the transmission decentering amount due to the positional deviation amount with respect to the outer center axis of the entrance surface center and the exit surface center of each lens excluding the resin lens 4 (base lens 3, single lens 5, 6), The position of the exit surface center 44b of the resin lens 4 is shifted by a predetermined amount with respect to the exit surface center 33b of the base lens 3 so that the entire lens system is offset by the transmission eccentricity by the resin lens 4. 4 is bonded to the base lens 3.

  As a result, as shown in FIG. 19, the entrance surface center 33a and the exit surface center 33b of the base lens 3 of the composite lens 2 are connected with the composite lens 2 and the single lenses 5 and 6 incorporated in the lens barrel 7. As shown by a line segment 70, a line segment 72 connecting the entrance surface center 55a and the exit surface center 55b of the single lens 5, and a line segment 73 connecting the entrance surface center 66a and the exit surface center 66b of the single lens 6 respectively. Even if the lenses 2, 5, and 6 are decentered, the amount of decentering is canceled by the decentering of transmission (line segment 71) by the resin lens 4 as the entire lens system.

  In this way, the transmission eccentricity caused by the base lens 3 and the single lenses 5 and 6 is canceled out as a whole lens system by the transmission eccentricity caused by the resin lens 4. Can be minimized. Alternatively, the transmission eccentricity can be eliminated. As a result, the light transmitted through the compound lens 2 and the single lenses 5 and 6 can be imaged satisfactorily in the image pickup device 9, and the resolution can be prevented from being reduced or half of the image can be prevented from being blurred.

Embodiment 2
In the first embodiment, the method for manufacturing the photographing lens based on the positional deviation amount of the center of the entrance surface or the center of the exit surface with respect to the center axis of the outer shape of the lens has been described. Here, a description will be given of a method of manufacturing a photographing lens based on the amount of positional deviation of the center of the entrance surface or the center of the exit surface with respect to the barrel center axis in a state where the remaining lenses other than the resin lens are disposed in the lens barrel.

  First, as shown in FIGS. 20 and 21, the base lens 3 and the single lenses 5 and 6 are disposed at predetermined positions in the lens barrel 7. At this time, for example, by aligning portions (not shown) corresponding to the gates when the base lens 3 and the single lenses 5 and 6 are molded, the base lens 3 and the single lenses 5 and 6, respectively. Are arranged with their circumferential positions aligned.

  Next, in a state where the base lens 3 and the single lenses 5 and 6 are disposed on the lens barrel 7 (FIG. 21), using the eccentricity measuring instrument, The amount of positional deviation between the center of the entrance surface and the center of the exit surface of each lens with respect to the barrel center axis 12 is measured. This positional deviation amount will be described in more detail.

  As shown in FIG. 22, consider an XY plane having an origin O at a point orthogonal to the barrel central axis 12 and intersecting the barrel central axis 12. A position where a straight line passing through the entrance plane center 14 and parallel to the barrel center axis 12 intersects the XY plane is defined as a position 14b, and a position passing through the exit plane center 16 and parallel to the barrel center axis 12 intersects with the XY plane. Assuming that the position is 16b, the amount of positional deviation between the incident surface center 14 and the barrel center axis 12 is obtained as the distance between the position 14b and the origin O. Further, the positional deviation amount between the emission surface center 16 and the barrel center axis 12 is obtained as a distance between the origin O and the position 16b.

  Next, the base lens 3 and the base lens 3 and the single lenses 5 and 6 are determined on the basis of the positional deviation amount with respect to the barrel center axis 12 between the entrance surface center 14 and the exit surface center 16. The amount of transmission eccentricity in a state where the single lenses 5 and 6 are disposed in the lens barrel 7 is obtained by optical calculation.

  Next, in a state where the resin lens is bonded to the base lens and disposed in the lens barrel 7 together with the single lenses 5 and 6 as the compound lens 2 (the entire lens system), the obtained transmission eccentricity amount is canceled out. Furthermore, a positional deviation amount T (distance in the XY plane) for shifting the emission surface center 44b of the resin lens 4 with respect to the emission surface center 33b of the base lens 3 is calculated based on optical calculation. At this time, the circumferential positions of the compound lens 2 and the single lenses 5 and 6 are fixed positions.

  Next, a reference compound lens is produced in the same manner as described above, and the amount of displacement SO of the center position of the lens surface of the reference compound lens is measured. Next, in the same manner as described above, the center axis 22 of the mold 20 and the center axis of the lens holding unit 30 are actually used in order to obtain the calculated position deviation amount T based on the obtained position deviation amount SO. A positional shift amount S2 that should be relatively shifted from 31 is obtained.

  Next, a compound lens is manufactured based on the obtained positional deviation amount S2. First, through the same process as the process shown in FIGS. 4 to 7 described above, as shown in FIG. 23, with the central axis 22 of the mold 20 and the central axis 31 of the lens holding part 30 aligned, The base lens 3 is held in a predetermined posture with respect to the lens holding unit 30.

  Next, as shown in FIG. 24, the center axis 22 of the mold 20 is slid relative to the center axis 31 of the lens holding portion 30 by the calculated positional deviation amount S2. Next, an ultraviolet curable resin 40 is injected into the recess 21 of the mold 20. Next, the lens holding unit 30 is lowered to place the base lens 3 on the mold 20, and a predetermined lens surface of the base lens 3 is brought into contact with the resin 40.

  Next, as shown in FIG. 25, the resin 40 is cured by irradiating ultraviolet rays. After the resin 40 is cured, the resin lens 4 is taken out from the mold 20 to complete the composite lens 2 in which the resin lens 4 is bonded to the base lens 3 as shown in FIG. In this compound lens 2, the output surface center 33 b of the base lens 3 and the output surface center 44 b of the resin lens 4 are errors (positional deviation amount SO) when the resin lens 2 is molded and joined to the base lens 3. In consideration of the above, the position is displaced by the amount of displacement S2.

  Next, as shown in FIG. 27, the compound lens 2 and the single lenses 5 and 6 are arranged in the lens barrel 7. At this time, as described above, the circumferential positions of the compound lens 2 and the single lenses 5 and 6 are arranged to be aligned. In this way, as shown in FIG. 28, the photographing lens 1 in which the compound lens 2 and the single lenses 5 and 6 are arranged in the lens barrel 7 as a plurality of lenses is completed.

  According to the photographing lens 1 described above, transmission eccentricity is caused by the amount of positional deviation of the center of the entrance surface and the center of the exit surface with respect to the barrel central axis 12 of each lens (base lens 3, single lens 5, 6) except the resin lens. The position of the exit surface center 44b of the resin lens 4 is shifted by a predetermined amount with respect to the exit surface center 33b of the base lens 3 so that the amount is offset by the transmission eccentricity by the resin lens 4 as a whole. The resin lens 4 is bonded to the base lens 3.

  As a result, as shown in FIG. 27, the entrance surface center 33a and the exit surface center 33b of the base lens 3 of the composite lens 2 are connected with the composite lens 2 and the single lenses 5 and 6 incorporated in the lens barrel 7. As shown by a line segment 75, a line segment 77 connecting the entrance surface center 55a and the exit surface center 55b of the single lens 5, and a line segment 78 connecting the entrance surface center 66a and the exit surface center 66b of the single lens 6, respectively. Even if the lenses 2, 5, and 6 are decentered in transmission, the transmission decentering (amount) is canceled out as a whole by the transmission decentering (line segment 76) by the resin lens 4.

  According to the simulation, for example, the y-direction component of the transmission eccentricity (line segment 75) by the base lens 3 is 1 μm, the y-direction component of the transmission eccentricity (line 77) by the single lens 5 is 3 μm, and the single lens 6 is used. If the y-direction component of the transmission eccentricity (line segment 78) is set to 2 μm, the y-direction component of the transmission eccentricity (line segment 76) by the resin lens 4 is set to −4 μm, so that the lens system of the taking lens 1 It was found that the entire transmission eccentricity amount disappeared.

  In this way, the transmission eccentricity caused by the base lens 3 and the single lenses 5 and 6 is canceled out as a whole lens system by the transmission eccentricity caused by the resin lens 4, and as shown by the line segment 79, the transmission eccentricity is obtained as the photographing lens 1. Can be minimized. Alternatively, the transmission eccentricity can be eliminated. As a result, the light transmitted through the cemented lens 4 and the single lenses 5 and 6 can be favorably imaged on the image sensor 9, and the resolution can be prevented from being reduced or half of the image can be prevented from being blurred.

  Further, in the manufacturing method described above, the compound lens 2 and the single lenses 5 and 6 are arranged in the lens barrel 7 with their respective circumferential positions aligned. As a result, when the lenses 2, 5, 6 are arranged in the lens barrel 7, the assembling work can be performed more efficiently than in the case where the circumferential positions are aligned, and the productivity can be improved. .

In the above-described photographing lens 1, the photographing lens 1 including one compound lens 2 and two single lenses 5 and 6 has been described as an example. The photographing lens is not limited to this, and can be applied to a photographing lens including at least one compound lens and at least one single lens.

  Further, as the order of manufacturing the compound lens 2, the base lens 3 is held in a predetermined posture on the lens holding unit 30, and the mold 20 is displaced by a predetermined amount with respect to the lens holding unit 30, and then the resin The case where the resin lens 4 is bonded to the base lens 3 by injecting 40 into the mold 20 has been described as an example. As a process of bonding the resin lens 4 to the base lens 3, first, the mold 20 is displaced by a predetermined amount with respect to the lens holding portion 30, and then the base lens 3 is held by the lens holding portion 30. The resin lens 4 may be bonded.

Embodiment 3
Here, a description will be given of a compound lens manufactured based on the amount of positional deviation at the center of the incident surface with respect to the central axis of the outer shape of the lens described in Embodiment 1, or the method of manufacturing the same. As shown in FIG. 29, the compound lens 2 includes a base lens 3 and a resin lens 4, and the resin lens 4 is bonded to the emission surface 3b of the base lens. As the base lens 3, for example, ZEONEX (registered trademark) manufactured by Nippon Zeon Co., Ltd. or TOPAS (registered trademark) manufactured by Polyplastics Co., Ltd. is applied. As the resin lens 4, for example, fluorene acrylate is applied.

  As shown in FIG. 30 and FIG. 31, in this compound lens 2, the transmission eccentricity caused by the base lens 3 before the resin lens 4 is joined to the base lens 3 causes the resin lens 4 to be the base lens. After being bonded to the resin lens 3, the resin lens is arranged so that it is canceled as the compound lens 2 by the transmission eccentricity by the resin lens 4 in a state where the bonded compound lens 2 is disposed in the lens barrel 7 (see FIG. 1). The position of the center (outgoing surface center 44b) of the lens surface (outgoing surface 4b) of 4 and the position of the center of the emitting surface 3b (outgoing surface center 33b) of the base lens 3 are displaced by a predetermined amount S0. .

  In addition, in order to measure the amount of positional deviation between the base lens 3 and the resin lens 4, the base lens 3 is provided with a marker 3c on a surface (outgoing surface 3b) to which the resin lens 4 is bonded. A marker 3d is formed on the surface (incident surface 3a) opposite to the surface to which 4 is joined. On the other hand, a marker 4c is formed on the surface of the resin lens 4 (outgoing surface 4b). The marker 4c of the resin lens 4 is easily formed by, for example, transferring a cutting mark remaining on the mold to the resin lens.

  As shown in FIG. 32, the cutting trace 23a remaining at the center of the bottom of the recess 21 when the recess 21 is formed in the mold 20 by grinding can be used as the cutting trace. Further, as shown in FIG. 33, a cutting mark 23a remaining at the center of the bottom of the recess 21 and a cutting mark 23b remaining concentrically with respect to the center can be used. The shape (cross section) of such markers 3c, 3d, and 4c may be, for example, a convex shape (convex portion) as shown in FIG. 34, or a concave shape (as shown in FIG. 35). A recess).

  For example, in the resin lens 4 in which the concave marker 4c having a depth of 0.02 [mu] m and a rectangular cross-sectional shape is formed, the marker 4c does not affect the optical performance. In order to avoid the influence of the marker 4c on the optical performance, the depth of the concave marker 4c is preferably 0.1 μm or less, and the height of the convex marker 4c is preferably 0.1 μm or less.

  Next, an example of a method for manufacturing the above-described compound lens will be described. First, as described in the first embodiment, the amount of positional deviation between the entrance surface center 14 and the exit surface center 16 of the base lens 3 is measured using an eccentricity measuring device. Based on the amount of positional deviation, the transmission eccentricity caused by the base lens 3 is obtained in a state where the resin lens 4 is bonded to the base lens 3 and then disposed in the lens barrel as the compound lens 2 (entire lens system). A positional deviation amount T for shifting the emission surface center 44b of the resin lens 4 with respect to the emission surface center 33b of the base lens 3 is calculated so as to be canceled out. Further, a reference compound lens is manufactured, and as a manufacturing error, a positional deviation amount SO between the emission surface center of the base lens and the emission surface center of the resin lens is measured (see FIG. 12).

  Next, based on the calculated positional deviation amount T and the measured positional deviation amount SO, a positional deviation amount S1 for relatively shifting the central axis 22 of the mold 20 and the lens holding portion 31 is obtained. Next, the same processes as those shown in FIGS. 4 to 7 are performed, and the center axis 22 of the mold 20 and the center axis 31 of the lens holding portion 30 are aligned with each other as shown in FIG. The base lens 3 is held in a predetermined posture with respect to the lens holding unit 30. Next, as shown in FIG. 37, the center axis 22 of the mold 20 is slid relative to the center axis 31 of the lens holding portion 30 by the determined positional deviation amount S1.

  Next, an ultraviolet curable resin 40 is injected into the recess 21 of the mold 20. Next, the lens holding unit 30 is lowered to place the base lens 3 on the mold 20, and the emission surface of the base lens 3 is brought into contact with the resin 40. Next, as shown in FIG. 38, the resin 40 is cured by irradiating ultraviolet rays. After the resin 40 is cured, the resin lens 4 is taken out from the mold 20 to complete the composite lens 2 in which the resin lens 4 is bonded to the base lens 3 as shown in FIG.

  In this compound lens 2, the transmission decentering amount due to the positional deviation amount with respect to the center of the outer shape of the center of the entrance surface and the center of the exit surface of the base lens 3 is canceled by the transmission decentering amount of the resin lens 4 as the entire lens system. As described above, the resin lens 4 is bonded to the base lens 3 while the position of the output surface center 44b of the resin lens 4 is shifted by a predetermined amount with respect to the output surface center 33b of the base lens 3. Thereby, even if the base lens 3 is decentered in transmission, the amount of transmission decentering is canceled out as a whole lens system by the transmission decentering by the resin lens 4 (see FIG. 19). As a result, it is possible to prevent the light transmitted through the complex lens 2 from being imaged well on the imaging device, reducing the resolving power, and blurring half of the image.

  In addition, markers 3c and 3d are formed on the base lens 3, and markers 4c are formed on the resin lens 4 (see FIGS. 30 and 31). As a result, when the emission surface center 44b of the resin lens 4 is shifted with respect to the emission surface center 33b of the base lens 3, the positional deviation amount obtained from the markers 3c, 3d, and 4c of the compound lens manufactured as a trial is used. Can be easily shifted by a predetermined amount.

  Further, the marker 3c formed on the base lens 3 is formed on a surface (exit surface 3b) to which the resin lens 4 is bonded, while the marker 3d is a surface opposite to the surface (incident surface 3a). Is formed. Thereby, while being able to measure the deviation | shift amount (deviation amount A) of the output surface center 33b of the output surface 3b of the base lens 3, and the output surface center 44b of the output surface 4b of the resin lens 4, the base lens 3 The deviation amount (deviation amount B) between the incidence surface center 33a of the incidence surface 3a and the emission surface center 44b of the emission surface 4b of the resin lens 4 can also be measured.

  As a compound lens, the optical performance of a compound lens in which a resin lens is bonded to the exit surface of the base lens is sufficiently smaller than the curvature radius of the entrance surface (object side) than that of the exit surface (image side). It is influenced by the shift amount B rather than the amount A. Therefore, by forming the marker 3d on the incident surface 3a of the base lens 3, the shift amount B can be easily measured, which can contribute to the improvement of the optical performance.

  In addition, although the case where it manufactured based on the external shape central axis was mentioned as an example in the compound lens 2 mentioned above, you may manufacture based on a barrel central axis (Embodiment 2). In each embodiment, the case where the resin lens is bonded to the exit surface of the base lens as an example has been described as an example. However, the resin lens may be bonded to the entrance surface of the base lens. Furthermore, the cross-sectional shape of the marker is not limited to a rectangle, and may be a shape such as a triangle or a pentagon.

  The embodiment disclosed this time is an example, and the present invention is not limited to this. The present invention is defined by the terms of the claims, rather than the scope described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing of the imaging lens which concerns on Embodiment 1 of this invention. In the same embodiment, it is sectional drawing for demonstrating the entrance plane center with respect to an external shape central axis, and an output surface center. In the same embodiment, it is a perspective view for demonstrating the amount of position shift of the entrance plane center or the exit surface center with respect to the external shape central axis. FIG. 3 is a cross-sectional view showing a step for manufacturing a reference compound lens in the method for manufacturing the photographic lens shown in FIG. 1 in the embodiment. FIG. 5 is a cross-sectional view showing a step performed after the step shown in FIG. 4 in the same embodiment. FIG. 6 is a cross-sectional view showing a step performed after the step shown in FIG. 5 in the same embodiment. FIG. 7 is a cross-sectional view showing a step performed after the step shown in FIG. 6 in the same embodiment. FIG. 8 is a cross-sectional view showing a step performed after the step shown in FIG. 7 in the same embodiment. FIG. 9 is a cross-sectional view showing a step performed after the step shown in FIG. 8 in the same embodiment. In the same embodiment, it is a top view for demonstrating the structure of a metal mold | die. In the same embodiment, it is a top view for demonstrating the structure of a base lens. FIG. 10 is a plan view showing a step performed after the step shown in FIG. 9 in the same embodiment. FIG. 13 is a cross-sectional view showing a step performed after the step shown in FIG. 12 in the same embodiment. FIG. 14 is a cross-sectional view showing a step performed after the step shown in FIG. 13 in the same embodiment. FIG. 15 is a cross-sectional view showing a step performed after the step shown in FIG. 14 in the same embodiment. FIG. 16 is a cross-sectional view showing a step performed after the step shown in FIG. 15 in the same embodiment. FIG. 17 is a plan view showing a step performed after the step shown in FIG. 16 in the same embodiment. FIG. 18 is a perspective view showing a step performed after the step shown in FIG. 17 in the same embodiment. In the same embodiment, it is sectional drawing for demonstrating the transmission eccentricity in a photographic lens. It is a perspective view which shows 1 process of the manufacturing method of the imaging lens which concerns on Embodiment 2 of this invention. FIG. 21 is a perspective view showing a step performed after the step shown in FIG. 20 in the same embodiment. In the same embodiment, it is a perspective view for demonstrating the amount of position shift of the entrance plane center or the exit surface center with respect to the barrel center axis. FIG. 22 is a cross-sectional view showing a step performed after the step shown in FIG. 21 in the same embodiment. FIG. 24 is a cross-sectional view showing a step performed after the step shown in FIG. 23 in the same embodiment. FIG. 25 is a cross-sectional view showing a step performed after the step shown in FIG. 24 in the same embodiment. FIG. 26 is a cross-sectional view showing a step performed after the step shown in FIG. 25 in the same embodiment. FIG. 27 is a cross-sectional view showing a step performed after the step shown in FIG. 26 in the same embodiment. In the same embodiment, it is sectional drawing for demonstrating the transmission eccentricity in a photographic lens. It is sectional drawing of the compound lens which concerns on Embodiment 3 of this invention. FIG. 30 is a plan view of the compound lens shown in FIG. 29 in the same embodiment. FIG. 30 is another plan view of the compound lens shown in FIG. 29 in the embodiment. In the same embodiment, it is a top view for demonstrating the cutting trace of a metal mold | die. In the embodiment, it is another top view for demonstrating the cutting trace of a metal mold | die. FIG. 32 is a partial sectional view taken along a sectional line XXXIV-XXXIV shown in FIG. 30 and FIG. 31 or a sectional line XXXV-XXXV shown in FIG. FIG. 32 is a partial sectional view taken along a sectional line XXXIV-XXXIV shown in FIG. 30 and FIG. 31 or a sectional line XXXV-XXXV shown in FIG. 30, showing another sectional shape of the marker in the embodiment. In the same embodiment, it is sectional drawing which shows 1 process of the manufacturing method of a compound lens. FIG. 37 is a cross-sectional view showing a step performed after the step shown in FIG. 36 in the same embodiment. FIG. 38 is a cross-sectional view showing a step performed after the step shown in FIG. 37 in the same embodiment. FIG. 39 is a cross-sectional view showing a step performed after the step shown in FIG. 38 in the same embodiment. It is sectional drawing which shows the conventional photographic lens.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shooting lens, 2 Compound lens, 3 Base lens, 3a Incident surface, 3b Emission surface, 3c Marker, 4 Resin lens, 4a Incident surface, 4b Emission surface, 4c Marker, 5,6 Single lens, 5a Incident surface, 5b Exit surface, 6a entrance surface, 6b exit surface, 7 lens barrel, 8 filter, 9 imaging device, 11 outer shape central axis, 12 barrel center axis, 13 entrance surface, 14 entrance surface center, 15 exit surface, 16 exit surface center, 20 mold, 21 recess, 22
Central axis, 23 marker, 30 Lens holder, 31 Central axis, 40 Resin, 33a Incident surface center, 33b Ejection surface center, 44a Incident surface center, 44b Ejection surface center, 55a Incident surface center, 55b Ejection surface center, 66a Incident Center of surface, 66b Outgoing surface center, 200 Compound lens for reference.

Claims (15)

A photographic lens having a plurality of lenses,
A first lens in which a resin lens is bonded to a base lens;
A second lens disposed in a predetermined positional relationship with the first lens,
In the first lens, the transmission decentering amount caused by the base lens and the second lens before the resin lens is bonded is determined by the transmission decentering amount by the resin lens. The resin lens is joined to the base lens by shifting the position of the exit surface center of the resin lens and the exit surface center of the base lens by a predetermined amount so as to cancel out the entire lens system of two lenses. Shooting lens.   The photographing lens according to claim 1, wherein a predetermined first marker is formed on the resin lens with the emission surface center as a center.   The photographing lens according to claim 1, wherein a predetermined second marker is formed on the base lens with the emission surface center as a center.   The photographic lens according to claim 2, wherein the first marker and the second marker are annular convex portions or concave portions. A method of manufacturing a photographic lens in which at least a first lens in which a resin lens is bonded to a base lens and a second lens are provided,
The transmission decentering amount caused by the base lens and the second lens before joining the resin lens is determined as the entire lens system of the first lens and the second lens by the transmission decentering amount by the resin lens. Obtaining a predetermined amount of positional deviation between the center of the exit surface of the resin lens and the center of the exit surface of the base lens so as to be canceled,
Forming the first lens by bonding the resin lens to the emission surface of the base lens based on the obtained displacement amount;
And a step of arranging the first lens and the second lens in a predetermined positional relationship.   In the step of determining the amount of positional deviation, the positional deviation between the center of the incident surface and the center of the outgoing surface of each of the base lens and the second lens with reference to the outer central axis of the base lens and the second lens. The method of manufacturing a photographic lens according to claim 5, wherein the predetermined amount of positional deviation is obtained based on the amount.   In the step of obtaining the positional deviation amount, a transmission eccentricity amount is obtained in a state where the base lens and the second lens are arranged in a lens barrel where the first lens and the second lens are arranged. The method of manufacturing a photographic lens according to claim 5, wherein the predetermined positional deviation amount is obtained so as to cancel the transmitted transmission eccentricity amount.   In the step of forming the first lens, on the basis of the obtained positional deviation amount, a lens holding portion that holds the base lens and a mold that molds the resin lens are relatively shifted in the horizontal direction, The manufacturing method of the imaging lens in any one of Claims 5-7 which joins the said resin lens to the output surface of the said base lens. The step of forming the first lens includes:
Holding the base lens in a predetermined posture with respect to the lens holding portion;
Injecting resin to be the resin lens into the mold after relatively shifting the lens holding portion and the mold in the horizontal direction;
Placing the base lens held by the lens holding part in the state of maintaining the relative positional relationship in the horizontal direction on the mold and contacting the resin;
The method for manufacturing a photographic lens according to claim 8, further comprising a step of bonding the resin lens to the base lens by curing the resin. The step of forming the first lens includes:
A step of relatively shifting the lens holding portion and the mold in a horizontal direction, and injecting a resin to be the resin lens into the mold;
Placing the base lens on the mold and contacting the resin;
Holding the base lens in the lens holding portion in a predetermined posture;
The method for manufacturing a photographic lens according to claim 8, further comprising a step of bonding the resin lens to the base lens by curing the resin. UV curable resin is applied as the resin,
The method of manufacturing a photographic lens according to claim 5, wherein in the step of forming the first lens, the resin is cured by irradiating the resin with ultraviolet rays. A compound lens in which a resin lens is bonded to a base lens,
A resin lens having a first entrance surface and a first exit surface, wherein a predetermined first marker is formed on any one of the first entrance surface and the first exit surface;
A base having a second entrance surface and a second exit surface, wherein the resin lens is bonded, and a predetermined second marker is formed on at least one of the second entrance surface and the second exit surface. A compound lens with a material lens.   The compound lens according to claim 12, wherein the first marker is formed at the center of the one surface of the resin lens or with the surface center of the one surface as a center.   The compound lens according to claim 12 or 13, wherein the second marker is formed around the center of the at least one surface of the base lens.   The composite lens according to claim 12, wherein the first marker and the second marker are annular convex portions or concave portions.

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