JP7516022B2 - Cemented lens, lens unit and camera module - Google Patents

Description

The present invention relates to a cemented lens, a lens unit, and a camera module that can be used to configure an on-board camera mounted on a vehicle such as an automobile.

Conventionally, automobiles have been equipped with on-board cameras to assist with parking and prevent collisions through image recognition, and there are also attempts to apply this to autonomous driving. Camera modules such as on-board cameras generally include a lens unit that has a lens group consisting of multiple lenses arranged along an optical axis, a lens barrel that houses and holds the lens group, and an aperture member that is placed between at least one of the lenses in the lens group (see, for example, Patent Document 1).

Specifically, such a lens unit 100 is, for example, as shown in FIG. 5, a plurality of lenses constituting a group of lenses L used for imaging, here a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105, are assembled in a lens barrel 120 so as to be stacked with spacers 150 in between. In particular, in the case of a metal lens barrel 120, a cap 123 is screwed onto the object side end (upper end in FIG. 5) as a fastening member, and the front end lens 101, which is positioned closest to the object side of the lens group L, is fixed to the object side end of the lens barrel 120 by this cap 123, thereby holding the lens group L in the direction of the optical axis O within the lens barrel 120.

In addition, in the lens unit 100 configured in this way, two lenses located on the image side, for example, the third and fourth lenses 103 and 104, may be cemented together to form a cemented lens 200. The lenses 103 and 104 that form such a cemented lens 200 are assembled by fitting the convex surface 103a facing the image side of the third lens 103 located on the object side with the concave surface 104a facing the object side of the fourth lens 104 located on the image side, as shown in an enlarged view in FIG. 6, for example, and fixed with an adhesive.

More specifically, in the bonding of the cemented lens 200 by concave-convex engagement, adhesive is dripped near the center of the polished (ground) surface, the concave surface 104a, of the fourth lens 104, and in this adhesive-coated state, the third lens 103 is superimposed from above on the fourth lens 104 so that its polished (ground) surface, the convex surface 103a, faces the concave surface 104a of the fourth lens 104 in the direction of the optical axis O, and the convex surface 103a and the concave surface 104a are engaged. As a result, the adhesive spreads along the lens bonding surface 140 beyond the effective diameter R of the lenses 103 and 104 to reach the bonded outer peripheral edge (edge portion) 130 between the lenses 103 and 104 as shown in FIG. 7 (in FIG. 7, the portion of the adhesive that spreads to reach the edge portion 130 and remains there is indicated by reference numeral 250).

JP 2013-231993 A

In a cemented lens made by bonding two lenses made of glass materials with different linear expansion coefficients, when the temperature changes, for example when exposed to a high (or low) temperature environment, the amount of expansion (contraction) of these two lenses differs, resulting in a difference in the outer diameter of the lenses after expansion (contraction). This difference in lens outer diameter becomes a radial stress applied to the lens cemented surface, and when the temperature change becomes particularly large, the stress applied to the lens cemented surface also increases, causing distortion of the lens or the adhesive layer on the lens cemented surface being unable to withstand the stress, which can cause peeling from the periphery of the adhesive, a phenomenon known as bulging (which can also cause the cemented lens to peel off). In particular, if the adhesive peels off within the effective diameter R, a ghost phenomenon can occur.

The adhesive for bonding the cemented lens must be applied in sufficient quantity to cover and spread over the entire polished surface beyond the effective diameter R of the lens to obtain the desired optical characteristics. However, depending on the amount of adhesive applied, as shown in FIG. 7, the adhesive 250 may not remain on the edge 130 of the fourth lens 104, but may extend over the flat surface 104c of the flange portion 104b of the fourth lens 104 so that the adhesive overflows beyond the edge 130, and the adhesive may interfere with other components (spacer 150 in the case of FIG. 5) placed on this flat surface 104c. In such cases, problems such as tilting of other components may occur.

The present invention has been made in consideration of the above circumstances, and aims to provide a cemented lens, lens unit, and camera module that can prevent the adhesive used to bond the lenses from peeling off and can prevent the adhesive from overflowing more than necessary beyond the edge of the lenses.

In order to solve the above problems, the present invention provides a cemented lens comprising a pair of lenses cemented together by an adhesive applied over an area equal to or greater than the effective diameter of the lenses,
The bonding surfaces of the pair of lenses are textured outside the effective diameters of the lenses, and adhesive that flows out beyond the effective diameters of the lenses is retained by the unevenness caused by the texture.

In the above-mentioned configuration of the present invention, the bonding surface outside the effective diameter of the lens is textured, and the adhesive that flows out beyond the effective diameter of the lens is held by the unevenness caused by the texture. In other words, an anchor effect can be obtained in which the adhesive extending beyond the effective diameter of the lens bites into the unevenness caused by the texture, so that the bonding surface's holding force to hold the adhesive is increased and the adhesive strength is improved. Therefore, even if a cemented lens is formed by bonding two lenses made of glass materials with different linear expansion coefficients, the adhesive layer can fully withstand the radial stress applied to the lens bonding surface due to the difference in the outer diameter of the lenses after expansion (contraction) due to temperature change, and as a result, peeling of the adhesive can be prevented, and problems such as deterioration of optical characteristics and peeling of the lens due to peeling of the adhesive can be avoided. In addition, if the adhesive is held by the unevenness caused by the texture in this way, further outflow of the adhesive to the radial outward direction can be restricted, so that the adhesive can be prevented from overflowing beyond the edge portion of the lens (the outer peripheral edge of the bonded lens), and therefore, the adhesive can be prevented from interfering with other parts around the cemented lens, and the problems associated with this can be avoided.

In the above configuration, the lenses constituting the cemented lens may be made of any material such as glass or resin, but are generally glass lenses that are spherically processed by polishing (grinding). The cemented lens can be made of any combination of lenses, such as a combination of a lens with positive power and a lens with negative power. In the above configuration, the embossing may be provided on only one of the lenses constituting the cemented lens, or on both lenses. The embossing may be any type of processing that can roughen (make uneven) the polished (ground) surface of the lens that forms the cemented surface. For example, a roughening means such as a file may be attached to the outer periphery of a jig that polishes (grinds) the lens to make it spherical, and the embossing may be performed by the roughening means at the same time as the lens is polished (grinded). Alternatively, the embossing may be achieved by mechanical processing such as blasting, unevenness transfer processing, chemical processing, etc. In addition, in the above configuration, the "effective diameter" of the lens, as is well known, is the diameter of a parallel bundle of rays that emerges from an object point at infinity on the optical axis of the lens and passes through the lens, but the range of the effective diameter corresponds to the lens area through which light passes that is incident on the image sensor (image sensor) of the lens unit having a lens group including a cemented lens, and can be determined by the size of the image sensor.

The present invention also provides a cemented lens formed by cementing a pair of lenses together with an adhesive applied over an area equal to or greater than their effective diameters,
The bonding surfaces of the pair of lenses are characterized in that a stepped adhesive reservoir is provided outside the effective diameters of the lenses to collect adhesive that flows out beyond the effective diameters of the lenses.

In the above-mentioned configuration of the present invention, a stepped adhesive reservoir is provided on the joint surface outside the effective diameter of the lens, and the adhesive that flows out beyond the effective diameter of the lens is stored and held in the adhesive reservoir. Therefore, even if a cemented lens is formed by bonding two lenses made of glass materials with different linear expansion coefficients, the radial stress applied to the lens joint surface due to the difference in the outer diameter of the lenses after expansion (contraction) due to temperature change can be absorbed and buffered by the elasticity of the adhesive layer stored in the adhesive reservoir, and as a result, peeling of the adhesive due to such stress can be prevented, and problems such as deterioration of optical characteristics and peeling of the lens due to peeling of the adhesive can be avoided. In addition, if the adhesive is held in this way by the stepped adhesive reservoir, further outflow of the adhesive to the outside in the radial direction can be restricted, so that the adhesive can be prevented from overflowing beyond the edge portion (the outer peripheral edge of the joint) of the lens, and therefore the adhesive can be prevented from interfering with other parts around the cemented lens, and the problems associated with this can be avoided.

In the above configuration, the adhesive reservoir is preferably provided near the outer peripheral edge of the bonding surface, and may extend beyond the bonding surface. In this case, the adhesive reservoir is preferably formed on the bonding surface of one lens of the cemented lens located below along the optical axis, so that the adhesive can be effectively and reliably stored.

In addition, in the cemented lens having the above configuration with textured or stepped adhesive reservoirs, the cemented surface can be formed by bonding surfaces of any shape, such as fitting of concave and convex surfaces of lenses, or bonding of flat surfaces of lenses. The cemented surface may have both textured and stepped adhesive reservoirs, but there may be cases where the optical design does not allow for a sufficient cemented surface to be able to apply texture outside the effective diameter of the lens. In such cases, it is effective to provide stepped adhesive reservoirs near the outer peripheral edge of the cemented surface instead of textured to achieve the object of the present invention.

The present invention also provides a lens unit including a lens group in which a plurality of lenses are arranged along the optical axis of the lenses, and a lens barrel in which the lens group is housed,
The lens group includes a cemented lens having the above-described configuration.

Even in this configuration, because the cemented lens has the characteristic configuration described above, it is possible to prevent the adhesive used to bond the lenses from peeling off and to prevent the adhesive from overflowing more than necessary beyond the edge of the lenses.

A camera module according to the present invention includes the lens unit described above.
With this configuration, the effects of the lens unit described above can be obtained with the camera module.

According to the present invention, the bonding surface outside the effective diameter of the lens is textured or has a stepped adhesive reservoir, so that any adhesive that flows out beyond the effective diameter of the lens is held by the unevenness caused by the texture or is held in the adhesive reservoir, preventing the adhesive used to bond the lenses from peeling off and restricting the adhesive from overflowing more than necessary beyond the edge of the lens.

1 is a schematic cross-sectional view of a lens unit according to an embodiment of the present invention. 2 is an enlarged view of a main portion of a textured portion of a cemented lens (a laminated lens) that constitutes a lens group of the lens unit of FIG. 1 . FIG. FIG. 2 is an enlarged view of a main portion of a modified cemented lens (a laminated lens) constituting a lens group of the lens unit of FIG. 1, the cemented lens being provided with a stepped adhesive reservoir. 2 is a schematic cross-sectional view of a camera module including the lens unit of FIG. 1. FIG. 1 is a schematic cross-sectional view of a conventional lens unit. FIG. 6 is a side view of a cemented lens that constitutes a lens group of the conventional lens unit of FIG. 5 . FIG. 7 is an enlarged view of a portion X in FIG. 6 .

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The lens unit of the present embodiment described below is particularly for a camera module such as an in-vehicle camera, and is fixedly installed on the outer surface of a vehicle, with wiring drawn into the vehicle and connected to a display or other device. Hatching is omitted for multiple lenses in Figures 1 to 7.

Figure 1 shows a lens unit 11 according to one embodiment of the present invention. As shown in the figure, the lens unit 11 of this embodiment includes a cylindrical lens barrel 12 made of, for example, metal, a plurality of lenses arranged in the inner storage space S of the lens barrel 12, for example, five lenses consisting of, from the object side, a first lens 13, a second lens 14, a third lens 15, a fourth lens 16, and a fifth lens 17, and an aperture member 22. These lenses 13 to 17 and aperture member 22 are arranged partially via a spacer 30 that separates the lenses 14, 15, 16, and 17 from each other or the aperture member 22 from the lenses 14 and 15 in the optical axis direction.

In addition, in this embodiment, the aperture member 22 is located between the second lens 14 and the third lens 15, and is either an "aperture diaphragm" that limits the amount of transmitted light and determines the F-number, which is an index of brightness, or a "light blocking diaphragm" that blocks light rays that cause ghosts and light rays that cause aberrations. An in-vehicle camera equipped with such a lens unit 11 includes the lens unit 11, a substrate having an image sensor (not shown), and an installation member (not shown) for installing the substrate on a vehicle such as an automobile.

The lenses 13, 14, 15, 16, and 17 are assembled and stored in the inner storage space S of the lens barrel 12, and are stacked and arranged with their optical axes aligned, and the lenses 13, 14, 15, 16, and 17 are arranged along one optical axis O to form a group of lenses L used for imaging. In this case, the two third and fourth lenses 15 and 16 located on the image side form a cemented lens (laminated lens) 40. The first lens 13 located on the most object side of the lens group L is a spherical glass lens having a convex surface on the object side and a concave surface on the image side, and the third and fourth lenses 15 and 16 that form the cemented lens 40 are also glass lenses, and the other lenses 14 and 17 are resin lenses, but are not limited to this. In this embodiment, the lens barrel 12 is made of metal as described above, but may be made of resin. In addition, the surfaces of these lenses 13, 14, 15, 16, and 17 may be provided with anti-reflection films, hydrophilic films, water-repellent films, etc., as necessary.

A roughly cylindrical cap 23 is screwed onto the object side end 12b (upper end in FIG. 1) of the lens barrel 12 as a fastening member, and the first lens 13 is fixed to the object side end 12b of the lens barrel 12 by this cap 23. Specifically, the female thread 23a formed on the inner peripheral surface of the peripheral wall of the cap 23 is screwed into the male thread 12a formed on the outer peripheral surface of the object side end 12b of the lens barrel 12, and the radially inner peripheral edge 23b of the flange-like upper end is abutted against the step 13a formed on the outer peripheral edge of the surface 13c facing the object side of the first lens 13, and the first lens 13 is fixed to the object side end 12b by tightening this cap 23, and the lens group L is held in the lens barrel 12 in the optical axis direction.

In addition, an inner flange portion 24 having an opening with a diameter smaller than that of the fifth lens 17 is provided at the image side end (the lower end in FIG. 1) of the lens barrel 12, and the multiple lenses 13, 14, 15, 16, 17, 18, and 19 that make up the lens group L and the aperture member 22 are sandwiched and held between this inner flange portion 24 and the cap 23 in the optical axis direction.

The outer peripheral side surface 13b of the first lens 13 is provided with a stepped reduced diameter portion 13ba, the diameter of which is reduced at the image side portion of the lens 13, and an O-ring 26, for example, is attached to this reduced diameter portion 13ba as a sealing member. This O-ring 26 seals the gap between the object side end 12b of the lens barrel 12 and the first lens 13 by being compressed radially between the outer peripheral side surface 13b of the first lens 13 and the inner peripheral surface of the object side end 12b of the lens barrel 12, thereby preventing water, dust, and other fine particles from entering the lens barrel 12 from the object side end of the lens unit 11. In addition, an outer flange portion 25 is provided in a brim shape on the outer peripheral surface of the image side of the lens barrel 12, which is used when installing the lens barrel 12 in an in-vehicle camera.

The third and fourth lenses 15 and 16 of the present embodiment constituting the cemented lens 40 are formed by grinding (polishing) a glass material to give them a spherical surface, and have different linear expansion coefficients. Specifically, as shown in FIG. 2, the third lens 15 has a surface facing the image side formed as a convex surface 15a and a surface facing the object side formed as a convex surface 15b, while the fourth lens 16 has a surface facing the object side formed as a concave surface 16a and a surface facing the image side formed as a convex surface 16b. The third and fourth lenses 15 and 16 are assembled (bonded together) to form a cemented surface 60 by fitting the convex surface 15a facing the image side of the third lens 15 located on the object side with the concave surface 16a facing the object side of the fourth lens 16 located on the image side, and are bonded together by the adhesive 70 (see FIG. 2) applied to the cemented surface 60. The fourth lens 16 is set to have a larger diameter than the third lens 15, and has a flange portion 16c that extends radially outward from the outer peripheral edge (edge portion) 90 of the joint when bonded to the third lens 15, and one end face of the spacer 30 abuts on a flat surface 16d that forms the upper surface of this flange portion 16c.

The adhesive 70 for bonding and fixing the third and fourth lenses 15 and 16 together is applied in a sufficient amount so as to cover and spread over the entire polished surface beyond the effective diameter R of the lenses 15 and 16 to obtain the desired optical characteristics. Therefore, in this embodiment, a means is provided on the bonding surface 60 that can prevent the adhesive 70 for bonding the lenses 15 and 16 from peeling off and regulate the adhesive 70 from overflowing more than necessary beyond the edge portion 90 of the lenses 15 and 16. Specifically, in this embodiment, such a means is provided by embossing (the embossed portion is indicated by reference number 50 in FIG. 2) on the bonding surface 60, which is a curved surface that is outside the effective diameter R of the lenses 15 and 16 and has an extended curvature within the range of the effective diameter R of the lenses 15 and 16, as shown in an enlarged view in FIG. 2. Such an embossed portion 50 is designed to hold the adhesive 70 that flows out beyond the effective diameter R of the lenses 15 and 16 by the unevenness associated with the embossing.

In this embodiment, the textured portion 50 is provided only on the fourth lens 16 that constitutes the cemented lens 40, but it may be provided on both lenses 15, 16. The textured portion 50 may be formed in any form as long as it can roughen (make uneven) the polished (ground) surface of the lens 16 (15) that forms the cemented surface 60. For example, a roughening means such as a file may be attached to the outer periphery of a jig that polishes (grinds) the lens 16 (15) to make it spherical, and the lens 15 (16) may be polished (ground) and textured by the roughening means at the same time. Alternatively, the textured portion may be realized by mechanical processing such as blasting, unevenness transfer processing, chemical processing, etc.

3 shows another example of a means for preventing the adhesive 70 for bonding the lenses 15 and 16 from peeling off and for restricting the overflow of the adhesive beyond the edge 90 of the lenses 15 and 16. As shown in the figure, in this example, such a means is provided in the cemented lens 40A as a stepped adhesive reservoir 80. This adhesive reservoir 80 is provided on the cemented surface 60 of the lenses 15 and 16 outside the effective diameter R of the lenses 15 and 16, and is designed to accumulate the adhesive 70 that flows out beyond the effective diameter R of the lenses 15 and 16 in the stepped portion. In particular, in this embodiment, the adhesive reservoir 80 is formed from the concave surface 16a of the fourth lens 16 to the flat surface 16d so as to extend slightly beyond the cemented surface 60 near the outer peripheral edge (edge 90) of the cemented surface 60. The amount of adhesive 70 used to bond the lenses 15, 16 together is preferably an amount that allows the adhesive that overflows beyond the effective diameter R when bonded to fill the adhesive reservoir 80, or an amount slightly more than that. When the bonded lenses 15, 16 peel off, the presence of elastic adhesive at the position that is the starting point provides a buffering effect that alleviates the difference in radial stress between the two lenses that is applied to the lens bonding surface 60 due to the difference in the lens outer diameters after expansion (contraction) due to temperature changes, and peeling can be suppressed.

In the bonding form (bonding by concave-convex engagement) between the lenses 15 and 16 with the textured area 50 or adhesive pool 80 as shown in FIG. 2 or FIG. 3, adhesive is dripped near the center of the concave surface 16a, which is the polished (ground) surface of the fourth lens 16, and in such a state of adhesive application, the third lens 15 is superimposed on the fourth lens 16 from above so that the convex surface 15a, which is the polished (ground) surface, faces the concave surface 16a of the fourth lens 16 in the direction of the optical axis O, and the convex surface 15a and the concave surface 16a are engaged. As a result, the adhesive spreads beyond the effective diameter R of the lenses 15 and 16 along the lens bonding surface 60, but is at least partially captured by the textured area 50 or adhesive pool 80 as shown in FIG. 2 and FIG. 3, so that it does not flow beyond the edge portion 90 more than necessary.

Figure 4 is a schematic cross-sectional view of a camera module 300 of this embodiment having a lens unit 11 with the configuration of Figure 1. As shown, this camera module 300 is configured with the lens unit 11 according to Figure 1 with a filter 99 attached, that is, the lens unit 11 including the cemented lens 40 of Figure 2 with the textured portion 50, but it may also be configured with a lens unit including the cemented lens 40A of Figure 3 with the adhesive reservoir 80.

The camera module 300 includes an upper case (camera case) 301, which is an exterior component, and a mount (base) 302 that holds the lens unit 11. The camera module 300 also includes a sealing member 303 and a package sensor (imaging element) 304.

The upper case 301 is a member that exposes the object side end of the lens unit 11 and covers the other parts. The mount 302 is disposed inside the upper case 301 and has a female thread 302a that screws into the male thread 11a of the lens unit 11. The seal member 303 is a member that is interposed between the inner surface of the upper case 301 and the outer peripheral surface 12c of the lens barrel 12 of the lens unit 11, and is a member that maintains airtightness inside the upper case 301.

The package sensor 304 is disposed inside the mount 302, and is positioned to receive the image of the object formed by the lens unit 11. The package sensor 304 also includes a CCD, CMOS, or the like, and converts the light that is collected and reaches the package sensor 304 through the lens unit 11 into an electrical signal. The converted electrical signal is then converted into analog data or digital data, which is a component of the image data captured by the camera.

As explained above, in the above-mentioned configuration, the embossed area 50 or stepped adhesive reservoir 80 is provided on the bonding surface 60 outside the effective diameter R of the lenses 15, 16, and the adhesive 70 that flows out beyond the effective diameter R of the lenses 15, 16 is held in place by the unevenness caused by the embossing or the adhesive reservoir 80. This prevents the adhesive 70 that bonds the lenses 15, 16 from peeling off, and also prevents the adhesive 70 from overflowing more than necessary beyond the edge portions 90 of the lenses 15, 16.

1 and 2, an anchor effect can be obtained in which the adhesive 70 extending beyond the effective diameter R of the lenses 15, 16 bites into the unevenness caused by the texture, and the force of the bonding surface 60 to hold the adhesive 70 is increased, improving the adhesive strength. Therefore, even in the above-mentioned configuration in which a cemented lens is formed by bonding two lenses made of glass materials with different linear expansion coefficients, a buffer effect can be obtained that alleviates the difference in radial stress between the two lenses applied to the lens bonding surface 60 due to the difference in the outer diameters of the lenses after expansion (contraction) due to temperature change, and as a result, peeling of the adhesive 70 can be prevented, and problems such as deterioration of optical properties and peeling of the lenses 15, 16 caused by peeling of the adhesive 70 can be avoided. Furthermore, if the adhesive 70 is held in place in this manner by the unevenness caused by the grain, further outflow of the adhesive 70 radially outward can be restricted, so that a situation in which the adhesive 70 overflows beyond the edge portions 90 of the lenses 15, 16 can be avoided. As a result, it is possible to prevent the adhesive 70 from interfering with other parts such as the spacer 30 around the cemented lens 40, and to avoid any problems associated with this.
In addition, if a textured surface is formed on the lens cemented surface 60, when light passes through the textured surface, it is diffusely reflected, which causes ghosts. However, this can be suppressed by applying an ink coating that is compatible with the adhesive.

On the other hand, in the case of a stepped adhesive reservoir 80 as shown in Figure 3, the adhesive 70 that flows out beyond the effective diameter R of the lenses 15, 16 is stored and held in the adhesive reservoir 80. Therefore, even in the above configuration in which two lenses made of glass materials with different linear expansion coefficients are bonded together to form a cemented lens, the radial stress applied to the lens cemented surface 60 due to the difference in the outer diameters of the lenses after expansion (contraction) due to temperature changes can be absorbed and buffered by the elasticity of the adhesive layer stored in the adhesive reservoir, and as a result, peeling of the adhesive 70 due to such stress can be prevented, and problems such as deterioration of optical characteristics and peeling of the lens due to peeling of the adhesive 70 can be avoided. In addition, if the adhesive 70 is held in this manner by the stepped adhesive reservoir 80, any further outflow of the adhesive 70 radially outward can be restricted, preventing the adhesive 70 from overflowing beyond the edge portions 90 of the lenses 15 and 16. This also prevents the adhesive 70 from interfering with other components such as the spacer 30 around the cemented lens 40A, and thus avoids any associated problems.

The present invention is not limited to the above-described embodiment, and can be modified in various ways without departing from the gist of the invention. For example, the shapes of the lenses, lens barrels, etc., in the present invention are not limited to the above-described embodiment. Also, some or all of the above-described configurations may be combined, or some elements may be omitted from one of the above-described configurations. Thus, for example, instead of providing the textured portion 50 and the adhesive reservoir 80 separately and independently on the joining surface 60, the textured portion 50 and the adhesive reservoir 80 may be provided simultaneously on the joining surface 60.

REFERENCE SIGNS LIST 11 Lens unit 12 Lens barrel 13, 14, 15, 16, 17 Lens 15a Convex surface 16a Concave surface 40, 40A Cemented lens 50 Textured portion 60 Cemented surface 80 Adhesive reservoir 300 Camera module L Lens group O Optical axis

Claims (5)

A cemented lens is formed by bonding a pair of lenses together with an adhesive applied over an area equal to or greater than the effective diameter of the lenses,
a cemented lens comprising: a cemented surface of the pair of lenses formed by fitting a convex surface of one of the lenses into a concave surface of the other lens; and on the outside of the effective diameters of these lenses , unevenness is provided on the concave surface of the cemented surface, which is a curved surface with an extended curvature within the range of the effective diameters of the lenses, due to embossing for retaining adhesive that flows out beyond the effective diameters of the lenses . A cemented lens is formed by bonding a pair of lenses together with an adhesive applied over an area equal to or greater than the effective diameter of the lenses,
a cemented lens comprising: a convex surface of one of the lenses constituting the cemented lens being fitted into a concave surface of the other lens having a diameter larger than that of the one lens, thereby forming a cemented surface of the pair of lenses; and a stepped adhesive reservoir for collecting adhesive that exceeds the effective diameter of the lens is provided outside the effective diameters of these lenses, the stepped adhesive reservoir extending from the concave surface forming the cemented surface to a plane that does not form the cemented surface, radially outward from the concave surface. The cemented lens according to claim 2, characterized in that the adhesive pool extends beyond the cemented surface near the outer peripheral edge of the cemented surface. A lens unit including a lens group in which a plurality of lenses are arranged along an optical axis of the lenses, and a lens barrel in which the lens group is housed,
A lens unit comprising the lens group including the cemented lens according to claim 1 . A camera module comprising the lens unit according to claim 4, and an image sensor disposed at a position that receives an image formed by the lens unit.

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