WO2014162846A1

WO2014162846A1 - Lens unit and imaging device

Info

Publication number: WO2014162846A1
Application number: PCT/JP2014/056856
Authority: WO
Inventors: 伸恭栗原; 宏梅田; 片桐　禎人
Original assignee: コニカミノルタ株式会社
Priority date: 2013-04-04
Filing date: 2014-03-14
Publication date: 2014-10-09

Abstract

Provided are a lens unit and an imaging device that ensure high-precision assembly and improved productivity, suppress unnecessary light, and are capable of suppressing the occurrence of ghosting or flaring. Unnecessary light incident to a functional surface (L4f3) is absorbed or diffused therefore incidence of said light to a light conversion unit (11a) is suppressed and ghosting and flaring can be avoided, as a result of the functional surface (L4f3) being provided on the inside in a direction orthogonal to the optical axis of a surface in contact with a fourth light-blocking plate (AP4) in an image side surface (L4f1) in a flange section (L4f) of a fourth lens (L4), said functional surface (L4f3) coating black ink or being a rough surface. In addition, unnecessary light emitted from outside the effective diameter of a third lens (L3) is absorbed therefore incidence of said light to a light conversion unit (11a) is suppressed and ghosting and flaring can be avoided, as a result of a third light-blocking plate (AP3) being provided between the third lens (L3) and the fourth lens (L4).

Description

Lens unit and imaging device

The present invention relates to a lens unit and an imaging apparatus suitable for use in an imaging apparatus having a solid-state imaging device such as a CCD type image sensor or a CMOS type image sensor.

In recent years, portable terminals equipped with an imaging device using a solid-state imaging device such as a CCD type image sensor or a CMOS type image sensor have become widespread. In such an imaging apparatus mounted on a portable terminal, an apparatus using an imaging element having a high pixel number has been supplied to the market so that a higher quality image can be obtained. An image pickup device having a large number of pixels has been accompanied by an increase in size, but in recent years, an increase in the density of pixels has progressed, and the image pickup device has been downsized. Along with this, the lens unit mounted on the imaging apparatus is also required to improve productivity while ensuring high-precision assembly in addition to a reduction in height.

To deal with such a problem, in FIGS. 7 to 8 of Patent Document 1, a flange portion outside the effective diameter of the lens is projected in the optical axis direction and brought into contact with an adjacent lens, and a plurality of lenses are overlapped. A lens unit is disclosed. According to such a lens unit, since the distance between the lenses in the optical axis direction can be easily adjusted by bringing the flange portions into contact with each other, high-precision assembly and improvement in productivity can be ensured.

However, the lens unit disclosed in Patent Document 1 has the following problems. In general, light rays that pass outside the effective diameter of the lens become unnecessary light and enter the imaging surface, causing ghosts and flares and hindering the formation of high-quality images. Therefore, a light shielding plate is disposed between the lenses to block unnecessary light, but in the case of the lens unit of Patent Document 1, since the flange portion protrudes in the optical axis direction and is in contact with the adjacent lens, The light shielding plate provided between the lenses physically stays on the inner side of the flange portion in the direction perpendicular to the optical axis. Therefore, the light cannot pass through the outer side of the light shielding plate in the direction perpendicular to the optical axis, which may become unnecessary light. There is. On the other hand, as shown in FIG. 2 of Patent Document 1, if the light shielding plate is extended to the lens frame, unnecessary light can be prevented from passing through the outside of the light shielding plate in the direction perpendicular to the optical axis. As a result, the total length of the optical axis varies, and there is a problem that a highly accurate lens unit cannot be formed. This is a problem that cannot be ignored particularly in a lens unit having a large number of lenses.

On the other hand, in Patent Document 2, a groove shape is formed outside the effective diameter of the lens, and unnecessary light is reflected on the inclined surface to prevent the incident light from entering the imaging surface. However, when mass-producing high-precision lenses at low cost, it is unavoidable to rely on plastic molding. However, in order to further promote lens thinning, the lens disclosed in Patent Document 2 is as follows. Forming problems arise. That is, when the concave portion is formed outside the effective diameter of the thin lens as shown in FIG. 1 so as to contribute to the function of reflecting unnecessary light using a convex mold, the material flows out from the gate into the cavity. As a result, the moldability deteriorates. Further, in the method of suppressing unnecessary light by reflection outside the effective diameter, not all unnecessary light can be dealt with, and more effective blocking of unnecessary light is desired.

Next, Patent Document 3 discloses a technique for suppressing unnecessary light by adjusting the arrangement position of the light shielding plate. However, the method of suppressing unnecessary light by adjusting the arrangement position of the light shielding plate does not necessarily cope with all unnecessary light, and more effective blocking of unnecessary light is desired.

Furthermore, Patent Document 4 discloses a technique for absorbing incident unnecessary light by applying a black paint or the like to an inclined portion outside the effective diameter. However, in the lens of Patent Document 4, if the inclined portion is only blackened, unnecessary light is allowed to pass through the outside of the blackened inclined portion in the direction perpendicular to the optical axis, thereby causing ghost and flare. The risk of causing it increases. On the other hand, Patent Document 4 suggests that the inclined portion is blackened by two-color molding, but it is difficult to create a lens by two-color molding. Further, although not described in Patent Document 4, although it is conceivable to apply a black paint to the outside of the inclined portion of the lens in the direction orthogonal to the optical axis, the optical axis when the lenses are overlapped due to the thickness of the black paint. Since the distance varies, there is a problem that a highly accurate lens cannot be assembled.

JP 2009-282264 A JP 2011-242504 A JP 2009-282423 A JP 2008-122801 A

The present invention has been made in view of the above problems, and an object thereof is to provide a lens unit and an imaging apparatus that can suppress generation of ghosts and flares while suppressing unnecessary light while ensuring high-precision assembly and productivity improvement. .

The lens unit according to the present invention comprises:
A plurality of lenses formed in series so that the protruding portions protruding in the optical axis direction are formed outside the effective diameter, and the protruding portions are in contact with each other;
An annular light shielding plate interposed between two of the plurality of lenses and disposed on the inner side in the direction perpendicular to the optical axis with respect to the protrusion,
A lens frame that houses the lens,
Of the surface of the lens, a portion outside the effective diameter and other than the surface in contact with another component is a functional surface that diffuses or absorbs light.

According to the present invention, the light that passes through the inside of the effective diameter and becomes unnecessary light can be suppressed by the ghost and flare by being captured by the light shielding plate. On the other hand, unnecessary light passing through the outside of the light shielding plate in the direction perpendicular to the optical axis is diffused or absorbed by being incident on the functional surface, thereby suppressing generation of ghosts and flares. Furthermore, since the functional surface is provided on a portion of the surface of the lens that is outside the effective diameter and other than the surface in contact with other parts, the distance between the lenses depends on the surface properties of the functional surface. Therefore, the distance between lenses can be ensured with high accuracy, and a highly accurate lens unit can be formed. The “other parts” refers to a light shielding plate, another lens, a lens frame, and the like.

Another lens unit according to the present invention is:
A plurality of small-diameter lenses formed in series so that the protruding portions protruding in the optical axis direction are formed outside the effective diameter, and the protruding portions are in contact with each other;
An annular small-diameter light-shielding plate that is interposed between two small-diameter lenses among the plurality of small-diameter lenses and is disposed on the inner side in the optical axis orthogonal direction with respect to the protruding portion,
A large-diameter lens arranged in series on the image side with respect to the plurality of small-diameter lenses;
A large-diameter light shielding plate disposed between the plurality of small-diameter lenses and the large-diameter lens;
A lens frame that houses the small-diameter lens and the large-diameter lens,
Any one of the plurality of small diameter lenses is coaxially fitted to the lens frame, and the large diameter lens is coaxially fitted to the lens frame,
The outer periphery of the large-diameter light shielding plate is disposed so as to contact the inner periphery of the lens frame,
Of the at least one surface of the small-diameter lens and the large-diameter lens, a portion other than the surface that is outside the effective diameter and is in contact with another component is a functional surface that diffuses or absorbs light. .

According to the present invention, the light that passes through the effective diameters of the small-diameter lens and the large-diameter lens and becomes unnecessary light is captured by the small-diameter light-shielding plate and the large-diameter light-shielding plate. Generation can be suppressed. On the other hand, unnecessary light passing through the outside of the small-diameter light shielding plate in the direction perpendicular to the optical axis is diffused or absorbed by being incident on the functional surface, or captured by the large-diameter light shielding plate, thereby generating ghost and flare. Can be suppressed. Furthermore, since the functional surface is provided in a portion other than the surface that is outside the effective diameter and abuts against other components, at least one surface of the small-diameter lens and the large-diameter lens. It is not affected by the surface properties of the functional surface, and therefore the distance between the lenses can be ensured with high accuracy and a highly accurate lens unit can be formed.

An imaging apparatus according to the present invention includes the lens unit described above and a solid-state imaging device.

According to the present invention, it is possible to provide a lens unit and an imaging apparatus capable of suppressing unnecessary light and suppressing generation of ghosts and flares while ensuring highly accurate assembly and productivity improvement.

It is sectional drawing along the optical axis of the imaging device 10 concerning this Embodiment. It is a figure which expands and shows the arrow II part of FIG. It is the front view (a) and back view (b) of the smart phone which mounts the imaging device 10. It is a control block diagram of the smart phone of FIG. FIG. 6 is a cross-sectional view of a five-lens lens unit, and is a view showing an optical path of unnecessary light. FIG. 6 is a cross-sectional view of a five-lens lens unit, and is a view showing an unnecessary light optical path. FIG. 4 is a cross-sectional view of a four-lens lens unit, and is a view showing an unnecessary light optical path. FIG. 4 is a cross-sectional view of a four-lens lens unit, and is a view showing an optical path of unnecessary light. It is sectional drawing of a 6-unit lens unit, Comprising: It is a figure shown with the optical path of unnecessary light. It is sectional drawing of a 6-unit lens unit, Comprising: It is a figure shown with the optical path of unnecessary light. It is sectional drawing of the lens unit of another embodiment. It is sectional drawing of the lens unit of another structure, Comprising: It is a figure shown with the optical path of unnecessary light. It is sectional drawing of the lens unit of another structure, Comprising: It is a figure shown with the optical path of unnecessary light. It is sectional drawing which expands and shows a part of lens unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view along the optical axis of the imaging apparatus 10 according to the present embodiment. The following configuration is a schematic diagram, and some shapes, dimensions, and the like are different from actual ones.

As shown in FIG. 1, the imaging device 10 causes a CMOS type imaging device 11 as a solid-state imaging device provided with a photoelectric conversion unit (light receiving surface) 11 a and the photoelectric conversion unit 11 a of the imaging device 11 to capture a subject image. The imaging lens 12, a lens frame 13 that accommodates the imaging lens 12, an IR cut filter 14 that has a parallel plate shape, and a substrate 15 that supports the imaging element 11 are included.

As shown in FIG. 1, the image pickup device 11 is an image pickup device in which pixels (photoelectric conversion elements) are two-dimensionally arranged at the center of the light receiving side (upper surface in FIG. 1) on a parallel plate chip. A photoelectric conversion unit 11a as a surface is formed, and a signal processing circuit (not shown) is formed around the photoelectric conversion unit 11a. Such a signal processing circuit includes a drive circuit unit that sequentially drives each pixel to obtain a signal charge, an A / D conversion unit that converts each signal charge into a digital signal, and a signal that forms an image signal output using the digital signal. It consists of a processing unit and the like.

Further, a plurality of pads formed in the vicinity of the outer edge on the light receiving surface side in the chip of the image sensor 11 are connected to the substrate 15 by wires (not shown). The image sensor 11 converts the signal charge from the photoelectric conversion unit 11a into an image signal such as a digital YUV signal, and transmits the image signal to an external circuit (not shown) (for example, a control circuit included in a host device on which the image pickup device is mounted). It is like that. In addition, it is possible to receive power and a clock signal for driving the image sensor 11 from an external circuit. Here, Y is a luminance signal, U (= RY) is a color difference signal between red and the luminance signal, and V (= BY) is a color difference signal between blue and the luminance signal. Note that the image sensor is not limited to the above CMOS image sensor, and other devices such as a CCD may be used.

In FIG. 1, an imaging lens 12 having a five-lens configuration is provided inside a lens frame 13. The imaging lens 12 and the lens frame 13 constitute a lens unit. The imaging lens 12 includes, in order from the object side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, each having a flange portion outside the effective diameter. The image side surface L1f1 of the flange portion L1f of the first lens L1 protrudes toward the image side to form a protruding portion, and hits the object side surface L2f2 shifted to the image side in the flange portion L2f of the second lens L2. Yes. A donut-plate-shaped first light-shielding plate AP1 is disposed on the inner side in the optical axis orthogonal direction of the protruding portion of the flange portion L1f of the first lens L1. The first light shielding plate AP1 extends to the outside of the effective diameter of the first lens L1.

FIG. 2 is an enlarged view of an arrow II part of FIG. In FIG. 2, an inclined surface L1f3 is formed so as to be connected to the image side surface L1f1 of the flange portion L1f of the first lens L1, and an inclined surface L2f3 is formed so as to be connected to the object side surface L2f2 of the flange portion L2f of the second lens L2. Has been. The optical axes can be aligned by bringing the inclined surfaces L1f3 and L2f3 into contact with each other. In this figure, a gap that does not affect the performance is provided in consideration of solid variations such as component tolerances.

In FIG. 1, the image side surface L2f1 of the flange portion L2f of the second lens L2 protrudes toward the image side to form a protruding portion, and the object side surface L3f2 shifted to the image side in the flange portion L3f of the third lens L3. I'm hitting you. A donut-plate-shaped second light shielding plate AP2 is disposed on the inner side in the optical axis orthogonal direction of the protruding portion of the flange portion L2f of the second lens L2. The second light shielding plate AP2 extends to the outside of the effective diameter of the second lens L2. The relationship between the second lens L2 and the third lens L3 is the same as in FIG.

The image side surface L3f1 of the flange portion L3f of the third lens L3 protrudes toward the image side to form a protrusion, and contacts the object side surface L4f2 shifted to the image side in the flange portion L4f of the fourth lens L4. Yes. A donut-plate-shaped third light shielding plate AP3 is disposed on the inner side in the optical axis orthogonal direction of the protruding portion of the flange portion L3f of the third lens L3. The third light shielding plate AP3 extends to the outside of the effective diameter of the third lens L3. The relationship between the third lens L3 and the fourth lens L4 is the same as in FIG.

Between the image side surface L4f1 of the flange portion L4f of the fourth lens L4 and the object side surface L5f2 of the flange portion of the fifth lens L5, a fourth light shielding plate AP4 having a donut shape is in contact and sandwiched. The outer periphery of the fourth light shielding plate AP4 is in contact with the inner periphery of the lens frame 13, and the optical axis from the outermost periphery (indicated by the dotted line A) of the light beam passing through the effective diameter of the fourth lens L4 and the fifth lens L5. It extends in a cantilevered manner to a position outside in the orthogonal direction (the same applies to FIGS. 7 to 10 described later). On the inner side in the optical axis orthogonal direction of the image side surface L4f1 of the flange portion L4f of the fourth lens L4, a position shifted from the fourth light shielding plate AP4 to the object side (other than the surface abutting on [other components] in the claims) From the portion, that is, the position that does not contact the fourth light shielding plate AP4 in this embodiment) to the outside of the effective diameter of the fourth lens L4 is defined as a functional surface L4f3, and black ink is applied or roughened here. Since the functional surface L4f3 extends substantially perpendicular to the incident unnecessary light, the effect of suppressing unnecessary light is high.

Further, in the other lenses L2 to L4, black ink is applied to the surface outside the effective diameter that extends perpendicularly to the incident unnecessary light (portion other than the surface in contact with [other parts] in the claims). By applying or roughening the surface, higher unnecessary light suppression effect can be secured. In this example, black ink is applied or roughened on the outer peripheral surfaces of the flange portions L2f to L4f of the lenses L2 to L4. However, the black ink may be applied or roughened in any of the lenses L2 to L4 depending on the effect of suppressing unnecessary light.

The object side surface L1f2 of the flange portion L1f of the first lens L1 is in contact with the image side surface of the wall portion 13a having the opening of the lens frame 13, and the outer peripheral surface L1f4 of the flange portion L1f is the small diameter portion 13b adjacent to the wall portion 13a. It is in contact with the inner peripheral surface. On the other hand, the outer peripheral surface of the flange portion L5f of the fifth lens L5 is in contact with the inner peripheral surface of the lens frame 13 adjacent to the fourth light shielding plate AP4.

In the present embodiment, the first lens L1 to the fourth lens L4 constitute a small diameter lens, and the fifth lens L5 constitutes a large diameter lens. The first light shielding plate AP1 to the third light shielding plate AP3 constitute a small diameter light shielding plate, and the fourth light shielding plate AP4 constitutes a large diameter light shielding plate.

The IR cut filter 14 is disposed on the imaging element 11 side of the flange portion L5f of the fifth lens L5 via an annular spacer SP. The lower end of the lens frame 13 is in contact with the substrate 15 via an annular holder 16 that holds the IR cut filter 14.

¡The flange of each lens is accurately formed by injection molding. Accordingly, when assembled, the first lens L1, the first light shielding plate AP1, the second lens L2, the second light shielding plate AP2, the third lens L3, the third light shielding plate AP3, and the fourth lens L4 with respect to the lens frame 13. When assembled, the flange portions come into contact with each other, so that the relative position in the optical axis direction from the first lens L1 to the fourth lens L4 is accurately adjusted. In addition, since the thickness of the fourth light shielding plate AP4 is controlled with high accuracy, when the fifth lens L5 is assembled with the fourth light shielding plate AP4 interposed therebetween, the relative relationship in the optical axis direction between the fourth lens L4 and the fifth lens L5. The position is adjusted with high accuracy.

On the other hand, as the flange portions come into contact with each other, the optical axes from the first lens L1 to the fourth lens L4 are accurately aligned as shown in FIG. Further, the optical axes of the first lens L1 and the fifth lens L5 are accurately aligned via the lens frame 13.

The operation of the imaging device 10 described above will be described. FIGS. 3A and 3B show a state in which the imaging device 10 is mounted on a smartphone 100 as a mobile terminal. FIG. 4 is a control block diagram of the smartphone 100.

In the imaging device 10, for example, the object side end surface of the lens frame 13 is provided on the back surface of the smartphone 100 (see FIG. 3B), and is disposed at a position corresponding to the lower side of the liquid crystal display unit.

The imaging device 10 is connected to the control unit 101 of the smartphone 100 via an external connection terminal (an arrow in FIG. 4), and outputs an image signal such as a luminance signal or a color difference signal to the control unit 101 side.

On the other hand, as shown in FIG. 4, the smartphone 100 performs overall control of each unit, and a control unit (CPU) 101 that executes a program corresponding to each process, a switch such as a power source, a number, and the like using a touch pad. An input unit 60 for inputting instructions, and a display unit 65 for displaying captured images and the like in addition to predetermined data on a liquid crystal panel (however, the touch panel 70 serves as both the liquid crystal panel of the display unit and the touch pad of the input unit) And a wireless communication unit 80 for realizing various information communications with an external server, and a storage unit (ROM) storing necessary data such as a system program, various processing programs, and a terminal ID of the smartphone 100 91, various processing programs and data executed by the control unit 101, or processing data, or obtained by the imaging device 10 And a temporary storage unit used as a work area for temporarily storing image data, etc. (RAM) and a 92.

The smartphone 100 operates by operating the input unit 60, drives the imaging lens 12 by an actuator (not shown) to perform an autofocus operation, and presses the release button 71 or the like to operate the imaging device 10 to perform imaging. It can be performed. The image signal input from the imaging device 10 is stored in the storage unit 92 or displayed on the touch panel 70 by the control system of the smartphone 100, and further transmitted to the outside as video information via the wireless communication unit 80. Is done.

Next, with reference to FIGS. 5 and 6, the unnecessary light cutting function in the present embodiment will be described. In the example of FIG. 5, the light that has passed through the effective diameter of the first lens L1 is reflected by the image side optical surface of the second lens L2 and becomes unnecessary light. This unnecessary light is further reflected within the flange portion L2f of the second lens (if the intensity of the unnecessary light is high, a part of the unnecessary light incident on the outer peripheral surface L2f5 is absorbed by the black ink or diffused by the rough surface. However, since the remainder is reflected), it finally exits from the image side surface L2f1, but the object side surface L3f2 of the flange portion L3f of the third lens L3 that is in contact with this is also transparent. Incident light is further emitted from the image side surface L3f1, and is incident on the flange portion L4f from the object side surface L4f2 of the flange portion L4f of the fourth lens L4.

Here, when the functional surface L4f3 is not provided on the image side surface L4f1 of the flange portion L4f of the fourth lens L4 on the inner side in the optical axis orthogonal direction of the fourth light shielding plate AP4, after passing through this, the effective diameter of the fifth lens L5 is passed. There is a possibility that ghosts and flares may be generated by passing through and entering the photoelectric conversion unit 11a. However, in the present embodiment, black ink is applied or roughened on the inner side in the direction perpendicular to the optical axis of the surface of the image side surface L4f1 of the flange portion L4f of the fourth lens L4 that is in contact with the fourth light shielding plate AP4. Since the functional surface L4f3 is provided, unnecessary light that has entered the functional surface L4f3 substantially perpendicularly is absorbed or diffused, so that it is suppressed from entering the photoelectric conversion unit 11a, and ghost and flare can be avoided.

In the example of FIG. 6, light that has passed through the effective diameters of the first lens L1 and the second lens L2 enters the third lens L3, and then exits from outside the effective diameter as unnecessary light. Here, if the effective diameter of the third lens L3 is outside the light transmission surface, even if the third light shielding plate AP3 is provided between the third lens L3 and the fourth lens L4, unnecessary light passes and enters the photoelectric conversion unit 11a. Doing so may cause ghosts and flares. However, in the present embodiment, since the black side is applied or roughened to the image side surface L3f6 that is outside the effective diameter of the third lens L3 and does not come into contact with the third light shielding plate AP3, the image side surface L3f6 is used. Can absorb or diffuse unnecessary light that is incident on the light source, and is prevented from being emitted from outside the effective diameter of the third lens L3. Therefore, it is possible to prevent the light from entering the photoelectric conversion unit 11a and to avoid ghosts and flares.

The illustration shows only an example of the optical path of unnecessary light, and the light ray generated from the internal reflection or the like based on the angle and intensity of the light ray incident on the lens unit, and the lens shape in the lens unit. On the other hand, black ink or a roughened surface can be provided so as to prevent unnecessary light from entering the imaging surface. For example, in FIGS. 5 and 6, black ink and a roughened surface are also provided on the outer peripheral surface L3f5 of the third lens L3 and the outer peripheral surface L4f5 of the fourth lens L4. The above-mentioned examples are limited examples of unnecessary light, and unnecessary light can be generated in various directions depending on conditions such as the type and shape of the lens used in the lens unit and the material of the lens frame. Accordingly, the position where the black ink or the roughened surface is employed can be appropriately selected.

Next, with respect to another lens unit having the imaging lens 12 having a four-lens configuration, an unnecessary light cutting function will be described with reference to FIGS. In this example, the first lens L1 to the third lens L3 constitute a small diameter lens, and the fourth lens L4 constitutes a large diameter lens. The first light shielding plate AP1 to the second light shielding plate AP2 constitute a small diameter light shielding plate, and the third light shielding plate AP3 constitutes a large diameter light shielding plate. The basic configuration is the same as that of the above-described embodiment. In this example, black ink is applied to the image side surface L3f1 of the flange portion L3f of the third lens L3 on the inner side in the direction perpendicular to the optical axis, or a rough surface. A surface L3f3 is provided. Further, in the other lenses L2 to L3, by applying black ink to a surface outside the effective diameter that extends substantially perpendicular to the incident unnecessary light or making it a rough surface, a higher unnecessary light suppression effect is achieved. Can be secured. In this example, black ink is applied or roughened to the outer peripheral surfaces of the flange portions L2f to L3f of the lenses L2 to L3.

In the example of FIG. 7, the light that has passed through the effective diameter of the first lens L1 is reflected by the image side optical surface of the second lens L2 and becomes unnecessary light. This unnecessary light is further reflected within the flange portion L2f of the second lens (if the intensity of the unnecessary light is high, a part of the unnecessary light incident on the outer peripheral surface L2f5 is absorbed by the black ink or diffused by the rough surface. However, the remainder is reflected) and finally exits from the image side surface L2f1, but enters the flange portion L3f of the third lens L3 from here.

Here, since the functional surface L3f3 is provided on the image side surface L3f1 of the flange portion L3f of the third lens L3 on the inner side in the direction orthogonal to the optical axis of the surface that contacts the third light shielding plate AP3, the functional surface L3f3 is incident substantially perpendicularly. By absorbing or diffusing unnecessary light, it is suppressed from entering the photoelectric conversion unit 11a, and ghost and flare can be avoided.

In the example of FIG. 8, the light that has passed through the effective diameter of the first lens L1 enters the second lens L2, and then exits from outside the effective diameter as unnecessary light. Here, if the effective diameter outside the second lens L2 is a light transmission surface, even if the second light shielding plate AP2 is provided between the second lens L2 and the third lens L3, unnecessary light passes and enters the photoelectric conversion unit 11a. Doing so may cause ghosts and flares. However, in the present embodiment, since the black side is applied or roughened to the image side surface L2f6 that is outside the effective diameter of the second lens L2 and is not in contact with the second light shielding plate AP2, the image side surface L2f6 is used. Can absorb or diffuse the unnecessary light incident on the second lens L2 and suppress the emission from the outside of the effective diameter of the second lens L2. Therefore, the incident light to the photoelectric conversion unit 11a is suppressed, and ghost and flare can be avoided.

The illustration shows only an example of the optical path of unnecessary light, and the light ray generated from the internal reflection or the like based on the angle and intensity of the light ray incident on the lens unit, and the lens shape in the lens unit. On the other hand, black ink or a roughened surface can be provided so as to prevent unnecessary light from entering the imaging surface. For example, in FIGS. 7 and 8, black ink and a roughened surface are also provided on the outer peripheral surface L3f5 of the third lens L3. The above-mentioned examples are limited examples of unnecessary light, and unnecessary light can be generated in various directions depending on conditions such as the type and shape of the lens used in the lens unit and the material of the lens frame. Accordingly, the position where the black ink or the roughened surface is employed can be appropriately selected.

Next, with reference to FIGS. 9 and 10, an unnecessary light cutting function will be described with reference to FIGS. In this example, the first lens L1 to the fifth lens L5 constitute a small diameter lens, and the sixth lens L6 constitutes a large diameter lens. The first light shielding plate AP1 to the fourth light shielding plate AP4 constitute a small diameter light shielding plate, and the fifth light shielding plate AP5 constitutes a large diameter light shielding plate. The basic configuration is the same as that of the above-described embodiment. Further, in the other lenses L2 to L5, by applying black ink to a surface outside the effective diameter that extends substantially perpendicular to the incident unnecessary light, or using a roughened surface, a higher unnecessary light suppression effect is achieved. Can be secured. In this example, black ink is applied or roughened to the outer peripheral surfaces of the flange portions L2f to L5f of the lenses L2 to L5.

In the example of FIG. 9, the light that has passed through the effective diameter of the first lens L1 is reflected by the image side optical surface of the second lens L2 and becomes unnecessary light. The unnecessary light is further reflected in the flange portion L2f of the second lens, passes through the flange portion L3f of the third lens, enters the flange portion L4f of the fourth lens, and is reflected on the outer peripheral surface (unnecessary). If the light intensity is high, a part of the unnecessary light incident on the outer peripheral surface L4f5 is absorbed by the black ink or diffused by the rough surface, but the rest is reflected), and further emitted from the image side surface L4f1. To the flange portion L5f of the fifth lens L5.

Here, since the functional surface L5f3 is provided on the image side surface L5f1 of the flange portion L5f of the fifth lens L5 on the inner side in the direction perpendicular to the optical axis of the surface contacting the fifth light shielding plate AP5, the functional surface L5f3 is incident substantially perpendicularly. By absorbing or diffusing unnecessary light, it is suppressed from entering the photoelectric conversion unit 11a, and ghost and flare can be avoided.

In the example of FIG. 10, the light that has passed through the effective diameter of the first lens L1 enters the second lens L2, and then exits from the effective diameter as unnecessary light. Here, if the effective diameter outside the second lens L2 is a light transmission surface, even if the second light shielding plate AP2 is provided between the second lens L2 and the third lens L3, unnecessary light passes and enters the photoelectric conversion unit 11a. This may cause ghosts and flares. However, in the present embodiment, since the black side is applied or roughened to the image side surface L2f6 that is outside the effective diameter of the second lens L2 and is not in contact with the second light shielding plate AP2, the image side surface L2f6 is used. Can absorb or diffuse the unnecessary light incident on the second lens L2 and suppress the emission from the outside of the effective diameter of the second lens L2. Therefore, the incident light to the photoelectric conversion unit 11a is suppressed, and ghost and flare can be avoided.

The illustration shows only an example of the optical path of unnecessary light, and the light ray generated from the internal reflection or the like based on the angle and intensity of the light ray incident on the lens unit, and the lens shape in the lens unit. On the other hand, black ink or a roughened surface can be provided so as to prevent unnecessary light from entering the imaging surface. For example, in FIGS. 9 and 10, black ink and a roughened surface are provided on the outer peripheral surface L2f5 of the second lens L2, the outer peripheral surface L3f5 of the third lens L3, and the outer peripheral surface L5f5 of the fifth lens L5. The above-mentioned examples are limited examples of unnecessary light, and unnecessary light can be generated in various directions depending on conditions such as the type and shape of the lens used in the lens unit and the material of the lens frame. Accordingly, the position where the black ink or the roughened surface is employed can be appropriately selected.

FIG. 11 is a sectional view showing a five-lens lens unit according to another embodiment. In the present embodiment, the object side surface L2f2 of the flange portion L2f of the second lens L2 protrudes toward the object side to form a protruding portion, and the image shifted to the object side in the flange portion L1f of the first lens L1. It contacts the side surface L1f1. A donut-plate-shaped first light-shielding plate AP1 is disposed on the inner side in the optical axis orthogonal direction of the protruding portion of the flange portion L2f of the second lens L2.

The object side surface L3f2 of the flange portion L3f of the third lens L3 protrudes toward the object side to form a protrusion, and hits the image side surface L2f1 shifted to the object side in the flange portion L2f of the second lens L2. Yes. A donut-plate-shaped second light-shielding plate AP2 is disposed on the inner side in the optical axis orthogonal direction of the protruding portion of the flange portion L3f of the third lens L3.

The object side surface L4f2 of the flange portion L4f of the fourth lens L4 protrudes toward the object side to form a protruding portion, and hits the image side surface L3f1 shifted to the object side in the flange portion L3f of the third lens L3. Yes. A donut-plate-shaped third light-shielding plate AP3 is disposed on the inner side in the optical axis orthogonal direction of the protruding portion of the flange portion L4f of the fourth lens L4.

Between the image side surface L4f1 of the flange portion L4f of the fourth lens L4 and the object side surface L5f2 of the flange portion of the fifth lens L5, a fourth light shielding plate AP4 having a donut shape is in contact and sandwiched. The outer periphery of the fourth light shielding plate AP4 is in contact with the inner periphery of the lens frame 13, and the optical axis from the outermost periphery (indicated by the dotted line A) of the light beam passing through the effective diameter of the fourth lens L4 and the fifth lens L5. It extends in a cantilevered manner to a position outside in the orthogonal direction. On the inner side in the optical axis orthogonal direction of the image side surface L4f1 of the flange portion L4f of the fourth lens L4, a position shifted from the fourth light shielding plate AP4 to the object side (other than the surface abutting on [other components] in the claims) From the portion, that is, the position that does not contact the fourth light shielding plate AP4 in this embodiment) to the outside of the effective diameter of the fourth lens L4 is defined as a functional surface L4f3, and black ink is applied or roughened here. Since the functional surface L4f3 extends substantially perpendicular to the incident unnecessary light, the effect of suppressing unnecessary light is high.

The unnecessary light cutting function in this embodiment will be described. In the example of FIG. 12, the light incident on the effective diameter of the first lens L1 is reflected on the image side surface, further reflected on the object side surface L1f2 of the flange portion L1f, and then the transparent image side surface L1f1 and object The light enters the flange portion L2f of the second lens L2 through the side surface L2f2 and becomes unnecessary light. This unnecessary light is further reflected within the flange portion L2f of the second lens (if the intensity of the unnecessary light is high, a part of the unnecessary light incident on the outer peripheral surface L2f5 is absorbed by the black ink or diffused by the rough surface. However, the remainder may be reflected) and may eventually exit from the image side surface L2f1, but pass through the flange portion L3f of the third lens L3 and exit from the image side surface L3f1, and the flange portion of the fourth lens L4. The light enters the flange portion L4f from the object side surface L4f2 of L4f.

In the example of FIG. 13, the light that has passed through the effective diameter of the first lens L1 and entered the effective diameter of the second lens L2 is reflected on the image side surface and further reflected on the object side surface of the flange portion L2f. From here, the light enters the flange portion L3f of the third lens L3 via the transparent image side surface L2f1 and the object side surface L3f2, and becomes unnecessary light. This unnecessary light is further reflected in the flange portion L3f of the third lens (if the intensity of the unnecessary light is high, a part of the unnecessary light incident on the outer peripheral surface L3f5 is absorbed by the black ink or diffused by the rough surface. However, there are cases where the remainder is reflected and finally exits from the image side surface L3f1, but this enters the flange portion L4f from the object side surface L4f2 of the flange portion L4f of the fourth lens L4.

The illustration shows only an example of the optical path of unnecessary light, and the light ray generated from the internal reflection or the like based on the angle and intensity of the light ray incident on the lens unit, and the lens shape in the lens unit. On the other hand, black ink or a roughened surface can be provided so as to prevent unnecessary light from entering the imaging surface. For example, in FIGS. 12 and 13, black ink and a roughened surface are also provided on the outer peripheral surface L4f5 of the fourth lens L4. The above-mentioned examples are limited examples of unnecessary light, and unnecessary light can be generated in various directions depending on conditions such as the type and shape of the lens used in the lens unit and the material of the lens frame. Accordingly, the position where the black ink or the roughened surface is employed can be appropriately selected.

In the above embodiment, the outer peripheral surface of the flange portion of each lens is formed in parallel with the optical axis. However, the flange portion is configured so that unnecessary light is positively incident on the ink-coated surface or the roughened surface. The outer peripheral surface may be a tapered surface.

Hereinafter, preferred embodiments will be described together.

It is preferable that a thin black material is formed on the functional surface. By forming a thin film-like black material on the functional surface, unnecessary light can be absorbed and generation of ghosts and flares can be suppressed. “Formation of black material” includes application of black ink by inkjet, black ink stamp, black film coating, black tape application, and the like.

The functional surface is preferably a rough surface. By forming a roughened surface as the functional surface, unnecessary light can be absorbed and generation of ghost and flare can be suppressed. The “roughened surface” refers to a surface having a high degree of roughness obtained by molding with a die having a textured surface or a roughened surface, for example. Specifically, the average roughness Ra is 0.2 μm or more.

It is preferable that the functional surface is provided on the inner side in the direction perpendicular to the optical axis of the surface in contact with the light shielding plate. Accordingly, unnecessary light that has passed through the outside of the light shielding plate in the direction perpendicular to the optical axis can be incident on the functional surface and diffused or absorbed.

It is preferable that unnecessary light is incident on the functional surface substantially perpendicularly. Thereby, unnecessary light can be effectively suppressed.

It is preferable that the functional surface is an outer peripheral surface of the flange portion of the lens. Thereby, unnecessary light can be more effectively suppressed.

Any one of the plurality of lenses is coaxially fitted to the lens frame, and a large-diameter lens different from the plurality of lenses is coaxially fitted to the lens frame, Furthermore, it is preferable that an outer periphery of a ring-shaped large-diameter light-shielding plate disposed between the plurality of lenses and the large-diameter lens is in contact with an inner periphery of the lens frame. Since any one of the plurality of lenses is coaxially fitted to the lens frame, and a large-diameter lens different from the plurality of lenses is coaxially fitted to the lens frame. The coaxiality between the plurality of lenses and the large-diameter lens can be ensured, and the optical axis can be accurately aligned. In addition, since the outer periphery of the ring-shaped large-diameter light-shielding plate disposed between the plurality of lenses and the large-diameter lens is in contact with the inner periphery of the lens frame, unnecessary light is emitted by the large-diameter light-shielding plate. Can be effectively blocked.

The large diameter lens is preferably the most image side lens. If the large-diameter lens is the most image side lens, the tolerance for eccentricity with the plurality of lenses is relatively high, and adjustment during assembly is easy.

It is preferable that the outer peripheral surface of the flange portion of the lens has a tapered shape. Thereby, the direction of the unnecessary light incident on the outer peripheral surface of the flange portion can be adjusted and incident on the functional surface.

It is preferable that the outer peripheral surface of the flange portion of the small diameter lens has a tapered shape. Thereby, the direction of the unnecessary light incident on the outer peripheral surface of the flange portion can be adjusted and incident on the functional surface.

The present invention is not limited to the embodiments described in the specification, and other embodiments and modifications may be included for those skilled in the art from the embodiments and technical ideas described in the present specification. it is obvious. For example, not only the embodiment described above, but also a surface that does not come into contact with other components as long as it is outside the effective diameter can be a functional surface. For example, as shown in FIG. 14, the inner side in the optical axis orthogonal direction (L4f3) of the image side surface contacting the fourth light shielding plate AP4 in the flange portion L4f of the fourth lens L4, or the second to fourth lenses L2 to L4. In addition to the outer peripheral surfaces L2f5 to L4f5, black ink may be applied or roughened to the outer peripheral side surfaces L2f4 to L4f4 that do not come into contact with other lenses or the like. Similar processing can be applied to a surface that does not come into contact with other components of all lenses under the same conditions. Further, the flange portions of the lens are not limited to directly contacting each other, and can be assembled by interposing a spacer whose thickness is controlled.

DESCRIPTION OF SYMBOLS 10 Image pick-up device 11 Image pick-up element 11a Photoelectric conversion part 12 Imaging lens 13 Mirror frame 14 IR cut filter 15 Board | substrate 16 Holder 60 Input part 65 Display part 70 Touch panel 71 Release button 80 Wireless communication part 92 Memory | storage part 100 Smartphone 101 Control part L1-L6 lens

Claims

A plurality of lenses formed in series so that the protruding portions protruding in the optical axis direction are formed outside the effective diameter, and the protruding portions are in contact with each other;
An annular light shielding plate interposed between two of the plurality of lenses and disposed on the inner side in the direction perpendicular to the optical axis with respect to the protrusion,
A lens frame that houses the lens,
A lens unit characterized in that a portion of the surface of the lens that is outside the effective diameter and other than the surface that comes into contact with another component is a functional surface that diffuses or absorbs light.
The lens unit according to claim 1, wherein a thin black material is formed on the functional surface.
The lens unit according to claim 1, wherein the functional surface is a rough surface.
The lens unit according to any one of claims 1 to 3, wherein the functional surface is provided on an inner side in a direction orthogonal to the optical axis of a surface that contacts the light shielding plate.
The lens unit according to claim 4, wherein unnecessary light is incident on the functional surface substantially perpendicularly.
The lens unit according to any one of claims 1 to 3, wherein the functional surface is an outer peripheral surface of a flange portion of the lens.
Any one of the plurality of lenses is coaxially fitted to the lens frame, and a large-diameter lens different from the plurality of lenses is coaxially fitted to the lens frame, The outer periphery of a ring-shaped large-diameter light-shielding plate disposed between the plurality of lenses and the large-diameter lens is in contact with the inner periphery of the lens frame. The lens unit according to any one of the above.
The lens unit according to claim 7, wherein the large-diameter lens is a lens closest to the image side.
9. The lens unit according to claim 1, wherein the outer peripheral surface of the flange portion of the lens is tapered.
A plurality of small-diameter lenses formed in series so that the protruding portions protruding in the optical axis direction are formed outside the effective diameter, and the protruding portions are in contact with each other;
An annular small-diameter light-shielding plate that is interposed between two small-diameter lenses among the plurality of small-diameter lenses and is disposed on the inner side in the optical axis orthogonal direction with respect to the protruding portion,
A large-diameter lens arranged in series on the image side with respect to the plurality of small-diameter lenses;
A large-diameter light shielding plate disposed between the plurality of small-diameter lenses and the large-diameter lens;
A lens frame that houses the small-diameter lens and the large-diameter lens,
Any one of the plurality of small diameter lenses is coaxially fitted to the lens frame, and the large diameter lens is coaxially fitted to the lens frame,
The outer periphery of the large-diameter light shielding plate is disposed so as to contact the inner periphery of the lens frame,
Of the at least one surface of the small-diameter lens and the large-diameter lens, a portion other than the surface that is outside the effective diameter and is in contact with another component is a functional surface that diffuses or absorbs light. Lens unit.
The lens unit according to claim 10, wherein a thin black material is formed on the functional surface.
The lens unit according to claim 10, wherein the functional surface is a rough surface.
The lens unit according to any one of claims 10 to 12, wherein an outer peripheral surface of the flange portion of the small-diameter lens has a tapered shape.
An imaging apparatus comprising the lens unit according to any one of claims 1 to 13 and a solid-state imaging device.