WO2016009734A1

WO2016009734A1 - Optical structure and optical element

Info

Publication number: WO2016009734A1
Application number: PCT/JP2015/065936
Authority: WO
Inventors: 智子橋本; 学道重光; 小原　良和; 守計中田
Original assignee: シャープ株式会社
Priority date: 2014-07-17
Filing date: 2015-06-02
Publication date: 2016-01-21

Abstract

The purpose of the present invention is to reduce processing costs, lighten weight, and control stray light. A porous structure that includes a plurality of types of holes with diameters different from each other is formed on at least part of a lens barrel (3) disposed in the vicinity of a lens (2) or on at least part of light shielding resin (6) disposed in the vicinity of a light receiving lens (5).

Description

Optical structure and optical element

The present invention relates to an optical structure disposed in the vicinity of an optical lens, an optical element including the optical structure, and the like.

In recent years, various optical elements having an antireflection treatment for suppressing light reflection have been proposed. For example, Patent Document 1 discloses a lens barrel in which an uneven structure having a pitch of a predetermined wavelength or less is formed on the inner wall surface of the lens barrel. Patent Document 2 discloses a light absorption structure in which a plurality of minute recesses having a pitch of a predetermined wavelength or less are formed on the surface. Patent Document 3 discloses a lens barrel in which the inner wall surface of the lens barrel is coated with porous fine particles.

Japanese Patent Publication “Patent No. 5383188 (Registered October 11, 2013)” Japanese Patent Publication “JP 2011-59548 A” (published March 24, 2011) Japanese Patent Publication “JP 2012-2895 (January 5th, 2012)”

However, in order to form a concavo-convex structure such as the lens barrel of the above-mentioned Patent Document 1 by forming a concavo-convex structure (forming concavo-convex on the surface), a blasting process for creating a concavo-convex pattern on the mold is necessary, and the processing cost However, there is a problem that a certain amount of thickness is required for the product. In addition, since the uneven structure of the document only diffuses light, there is a problem in that part of stray light reaches the detector and imaging defects such as flare and ghost may occur. Moreover, even if the light diffusing effect due to the concavo-convex structure is used, it is not easy to prevent the light from entering the inside of the optical lens, and the reflection of the adhesive used to fix the lens barrel causes reflection of the inside of the optical lens. There is also a problem that there is a possibility that an incident to the light will occur and imaging defects such as flare and ghost may occur.

Next, in the light absorption structure of Patent Document 2, light reflection is suppressed by the minute recesses, but light that is not absorbed by the resin material is reflected. Therefore, in this structure, the surface of the resin portion other than the recesses is reflected. There is a problem that it is difficult to sufficiently suppress reflection.

Next, in the lens barrel of the above-mentioned Patent Document 3, there is a possibility that fine particles constituting the coating film made of porous fine particles formed on the inner wall surface may drop off, and there is a possibility that imaging defects may be caused by the foreign particles. There is a point. In addition, if the light absorption process is performed in the process after film formation, the process becomes complicated, and it may come off and cause dust, and the dimensional accuracy of the lens housing may be affected by the coating thickness error. There is also a problem.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical structure or the like that can reduce processing costs and weight, and can suppress stray light. .

In order to solve the above problems, an optical structure according to one embodiment of the present invention is an optical structure disposed in the vicinity of an optical lens, and includes a porous structure including a plurality of types of holes having different hole diameters. Is at least partially formed.

According to one aspect of the present invention, it is possible to reduce the processing cost and reduce the weight and to suppress stray light.

(A) is a figure which shows the structure of the lens unit which concerns on Embodiment 1 of this invention, (b) is a figure which shows the structure of the proximity sensor which concerns on Embodiment 2 of this invention. It is a figure which shows an example of the formation method of a porous structure, (a) is a figure which shows a mode when low temperature melt | dissolution particle | grains are mixed with the resin material (plastic powder), and is injection-molded, (b) These are figures which show a mode when the said low temperature melt | dissolved particle is dissolved, (c) is a figure which shows a mode when a pore is formed by eluting the said low temperature melt | dissolved particle completely. It is a figure which shows another example of the formation method of a porous structure, (a) is a figure which shows a mode just before a resin material is irradiated with a radiation, (b) is a resin material by irradiation of a radiation. It is a figure which shows the state in which the locus | trajectory of the radiation remained, (c) is a figure which shows a mode that the etching bath is performed with respect to the resin material of the state shown to (b) of FIG. 3, (d) is a figure. It is a figure which shows the structure of the porous structure made porous by the said etching bath. It is a figure which shows the structure of the porous structure produced by the two-step injection molding. It is a figure which shows the structure of the portable terminal which concerns on Embodiment 3 of this invention, (a) shows the structure of an example of the said portable terminal, (b) shows the structure of another example of the said portable terminal. It is a figure which shows the modification of a porous structure, (a) shows one modification of the said porous structure, (b) shows another modification of the said porous structure, (c), Another modification of the porous structure will be described. It is a figure which shows a mode when the lens unit of a comparative example and the lens unit which concerns on Embodiment 4 of this invention are compared, (a) And (b) moves the lens barrel of the lens unit of a comparative example up and down. (C) and (d) show the state when the lens barrel of the lens unit according to Embodiment 4 is moved up and down. It is a figure which shows the structure of the lens unit which concerns on Embodiment 5 of this invention. It is a figure which shows the structure of the lens unit which concerns on Embodiment 6 of this invention. It is a figure for demonstrating the problem of the lens unit of a comparative example, (a) is a figure for demonstrating one of the problems of the lens unit of the said comparative example, (b) is the said comparison. It is a figure for demonstrating another problem of the lens unit of an example. (A) is a figure which shows an example of the coating agent apply | coated to a lens-barrel. (B) And (c) is a figure which shows the method of apply | coating the porous agent containing the material which each forms a porous structure to the arbitrary site | parts of the conventional lens barrel. (A) And (b) is a figure which shows the example which utilizes the said porous agent for the conventional lens barrel 103, respectively. (A)-(d) is a figure which shows the example which uses the said porous agent as a light-shielding member, respectively.

Embodiments of the present invention will be described with reference to FIGS. 1 to 10 as follows. Hereinafter, for convenience of explanation, components having the same functions as those described in the specific embodiment may be denoted by the same reference numerals and description thereof may be omitted.

[Embodiment 1]
FIG. 1A is a diagram showing a configuration of a lens unit (optical element) 10a according to Embodiment 1 of the present invention. As shown in the figure, the lens unit 10a includes a detector (light receiving element) 1, a lens (optical lens) 2, and a lens barrel (optical structure).

(Detector 1)
The detector 1 is a light receiving element (image sensor) that receives light passing through the lens 2, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). Consists of.

(Lens 2)
The lens 2 is a lens constituting an imaging optical system that irradiates light passing through the light receiving surface of the detector 1 and forms an image on the light receiving surface. The lens 2 is composed of a plurality of lenses. FIG. 1 shows a state in which the lens 2 is composed of three lenses for convenience, but the number of lenses constituting the lens 2 is limited to three. Not.

(Lens barrel 3)
The lens barrel 3 is a casing in which a plurality of lenses (lenses 2) are assembled in the vicinity of the lens 2 and surrounds the periphery of the lens 2 in a cylindrical shape and is accommodated in the casing. is there. The lens barrel 3 of the present embodiment has a cylindrical shape that surrounds the periphery of the lens 2. The constituent material of the lens barrel 3 is not particularly limited, and examples thereof include olefin-based, styrene-based, elastomer-based, and synthetic rubber-based materials.

Further, as shown in FIG. 1, the whole or a part of the lens barrel 3 is formed with a porous structure (porous structure) including plural kinds of holes having different hole diameters. The porous structure is preferably formed on the inner side (inner wall surface side) that accommodates the lens 2 of the lens barrel 3 or around the lens opening in order to suppress stray light. Light incident on the inside of the lens barrel 3 or around the lens opening tends to be stray light. For this reason, according to the said structure, the lens-barrel 3 from which a stray light component is removed favorably can be provided. In the present embodiment, the porous structure described above is composed of a hole A having a pore diameter (distance d3) of 5 μm or more and a hole B having a pore diameter smaller than the hole A and having a pore diameter (distance d2) of 400 nm or more and 600 nm or less. Contains kinds of holes. The distance d2 is set to a size equal to or larger than the wavelength range of light received by the detector 1. In the present embodiment, there are two types of hole diameters. However, the number of hole diameters may be plural, and for example, three or more types of holes having different hole diameters may be included. The porous structure as described above is easy to process and can reduce the processing cost as compared with the anti-reflective structure having an uneven surface (providing unevenness on the surface). The details of the processing method (manufacturing method) of the porous structure will be described later. The porous structure includes a hole A having a large hole diameter and a hole B having a small hole diameter. Here, when disturbance light is incident on the optical lens, a part thereof may become stray light and enter the lens barrel 3. When the stray light enters the lens barrel 3, it is captured by the hole A having a large hole diameter. At this time, the stray light is scattered by the hole B if the hole diameter of the hole B having the smaller hole diameter is set to a size approximately equal to or larger than the wavelength range of stray light. For this reason, the stray light captured by the hole A is scattered by the hole B, and when multiple reflections are repeated by this, it may disappear as thermal energy. For this reason, part of the stray light disappears due to the porous structure, so that the stray light can be suppressed.

Next, when analyzing the porous structure of the present embodiment from a different viewpoint, a hole A (concave portion) having a hole diameter capable of capturing light of a predetermined wavelength and the hole A are continuously formed, It can also be seen that it includes a fine concavo-convex structure F having a concavo-convex interval (distance d1≈d2) smaller than the hole diameter of the hole A that scatters light captured by the hole A. Here, the unevenness interval (unevenness size) refers to the dimension of both the height direction of the unevenness on the surface and the unevenness of the interval. Further, the unevenness on the surface of the fine concavo-convex structure F may be expressed by the surface roughness of the portion excluding the large hole A. The above irregularity interval is set to a size equal to or larger than the wavelength range of the light received by the detector 1.

According to the above configuration, stray light is scattered by the fine concavo-convex structure if the concavo-convex interval of the fine concavo-convex structure F is set to a size about the stray light wavelength range or larger. For this reason, the stray light captured by the hole A is scattered by the fine concavo-convex structure F continuously formed with respect to the hole A, and thus, when multiple reflections are repeated, it may disappear as thermal energy. . For this reason, part of the stray light disappears due to the porous structure, so that the stray light can be suppressed. Further, if the above-described porous structure is formed on at least a part of the lens barrel 3, the lens barrel 3 can be reduced in weight by being porous compared to a dense structure having the same volume. Further, the lens barrel 3 can be easily manufactured by forming the porous structure on at least a part of the lens barrel 3, for example, so that the processing cost can be reduced. As described above, according to the lens barrel 3, it is possible to reduce the processing cost and reduce the weight, and to suppress stray light.

Further, when the optical lens is a visible light lens, the hole diameter (recess width) of the hole A (recess) may be 5 μm or more, and the unevenness interval of the fine uneven structure F may be 300 nm or more and 900 nm or less. According to the above configuration, for example, the lens barrel 3 from which the stray light component is satisfactorily removed can be obtained for the lens barrel 3 used in the imaging camera or the like. A light receiving element (detector 1) used for an imaging camera or the like detects light in a wavelength range of approximately 400 to 800 nm, which is a visible light range, and has a high sensitivity characteristic at about 550 nm with high visual sensitivity. Light outside the operating wavelength range is shielded by a coating made on glass or lenses, but since the emphasis is on the intermediate band of the operating wavelength with high visibility, light at the operating wavelength end is not assumed in the design The path becomes stray light, and even if the stray light is small, it often becomes a ghost or flare depending on the situation of use, which often affects image quality degradation. Since the light is scattered by the fine concavo-convex structure F having a concavo-convex interval equal to or greater than the wavelength, the imaging camera that detects visible light has a predetermined condition of the hole A and the fine concavo-convex structure F to scatter. The light directly guided to the hole A is repeatedly reflected by the fine concavo-convex structure F formed continuously with respect to the hole A, and disappears as heat energy.

Next, the diameter of each of the holes A and B described above may be 10 nm or more and 10 μm or less. According to the above configuration, dust can be prevented from entering, and distortion due to cloudiness or thermal expansion of the lens 2 can be suppressed, so that the lens barrel 3 with high environmental resistance can be obtained. The allowable size of dust is a few dozen μm, the size of water vapor is 4 nm, and the size of water droplets is 100 μm.

(Effect of the lens unit 10a)
According to said lens unit 10a, the stray light by the lens opening part of the lens-barrel 3 and internal reflection of a lens-barrel can be suppressed. Light is scattered by the fine concavo-convex structure F equal to or longer than the wavelength of light. This is because, when the porous structure described above is applied, stray light is trapped in the pores and disappears as thermal energy through multiple reflection.

More specifically, in the lens unit 10a, the whole or a part of the lens barrel 3 is formed with a porous structure having at least two types of hole diameters of holes A and B having different sizes. By trapping light in the hole A and preventing surface reflection, the trapped light is scattered in the portion of the hole B having a small hole diameter, thereby repeating multiple reflections and disappearing as thermal energy, thereby reducing stray light components. It becomes possible to suppress. In addition, light having an angle exceeding the total reflection critical angle is reflected by the theory of total reflection and cannot obtain a light absorption effect. However, in the lens barrel 3 described above, in order to reflect light in various directions, The reflected light can be reduced satisfactorily regardless of the incident angle of light.

Further, according to the lens barrel 3 described above, the weight is reduced by a porous amount compared to a dense lens barrel having the same volume. When the lens barrel 3 is reduced in weight, it is possible to perform autofocus and optical camera shake correction operations with a small amount of energy, so that power consumption can be reduced.

Also, for example, when the lens barrel 3 is used in a mobile terminal or the like, a driving mechanism is provided for camera focus adjustment, and collision noise may be generated due to external vibration. Therefore, according to the lens barrel described above, it is possible to expect the effect that the generated vibration propagates into the porous body and is converted into thermal energy to reduce sound.

In summary, according to the lens unit 10, the following effects can be obtained.
(1) It has the effect of suppressing stray light using light absorption.
(2) The weight of the lens barrel 3 is reduced, the burden on the drive mechanism is reduced by the reduction in thickness, and the accompanying low power consumption effect.
(3) Since an adhesive that connects the porous particles is not necessary, reflection by the adhesive is prevented.
(4) The die blasting process is not necessary, and the cost is reduced.
(5) Since porous particles are not sprayed, it is possible to suppress the generation of foreign particles due to particle peeling.
(6) Sound waves hit the pores of the porous structure, resulting in resistance friction, and sound energy is converted into heat energy, so that a sound absorption effect is obtained.
(7) Since reflection by the adhesive for holding the lens barrel 3 can be suppressed, the application range can be expanded and the holding power can be strengthened.

(Method for forming porous structure)
The porous structure described above is easier to process and can reduce processing costs as compared to the antireflection uneven structure by embossing (making the surface uneven). Hereinafter, some specific examples of the method for forming the porous structure will be described.

FIG. 2 is a diagram showing an example of a method for forming a porous structure. In this method, first, as shown in FIG. 2 (a), the resin material (plastic powder) is mixed with the low-temperature dissolved particles a and b to perform injection molding. The plastic powder and the low-temperature melting particles a and b are made of materials having different characteristics such as a melting temperature. As a constituent material of the low-temperature dissolution particles a and b, for example, water-soluble sodium chloride or sodium nitrate can be exemplified. Next, as shown in FIG. 2B, after the injection molding, the low-temperature dissolution particles a and b made of a resin having a low dissolution temperature are eluted. When the low-temperature dissolution particles a and b are completely eluted, a porous structure in which pores (holes A and B) as shown in FIG. 2C are formed is obtained.

Next, FIG. 3 is a diagram showing another example of a method for forming a porous structure. In this method, as shown in FIG. 3A, the resin material is irradiated with radiation. Thereby, as shown in (b) of Drawing 3, the locus of radiation remains inside the resin material. Next, as shown in FIG. 3C, the resin material with the radiation locus remaining is immersed in an etching solution, and an etching bath is performed. Then, the portion of the radiation locus remaining inside the resin material is etched to obtain a porous structure as shown in FIG.

Next, FIG. 4 is a diagram showing the structure of a porous structure created by two-stage injection molding. As shown in the figure, at the time of injection molding, a resin in which porous fine particles having different pore diameters are mixed is injected stepwise so that the pore diameters (for example, the respective hole diameters of the holes A and B) and portions (for example, the region α) , Β) can be controlled.

Examples of other porous structure forming methods include a sintering method, a track etching method, a spacer method, and fine foam injection molding.

For example, in the sintering method, a porous structure can be obtained by fusing (sintering) only the vicinity of the surface layer of the raw material powder and molding while leaving the voids existing between the raw material powders.

Also, in the track etching method, uniform size pores can be obtained by etching with an aqueous alkali solution after irradiating the polymer material with a neutron beam or laser.

Next, in the spacer method (space holder method), the lost substance is used as a spacer to adjust the porosity and pore size.

Also, in the fine foam injection molding, the foaming agent mixed resin is injected into the mold using an injection molding machine, and the foam molded product is taken out. At this time, the foaming agent to be used is nitrogen or carbon dioxide in a supercritical state, and it is possible to produce a foamed structure having closed cells of 5 to 100 μm. Further, this foam injection method is also possible for the outer part of the two-stage injection.

(Application example to conventional lens barrel)
As an example of another method for forming a porous structure, in addition to the above-described injection molding, there is a method in which a porous agent containing a material for forming a porous structure is applied to any part of a conventional lens barrel. The porous agent as the coating agent may contain a material suitable for coating (for example, epoxy resin, silicone resin, acrylic resin). The material suitable for application may be a material according to any part (plastic, nylon (registered trademark), LCP (Liquid Crystal Polymer), polycarbonate, etc.) of the lens barrel to be applied.

According to the above configuration, by applying a porous agent to a conventional lens barrel, it is possible to maintain the rigidity (hardness) strength of the lens barrel itself and to obtain a stray light suppression effect, which is low cost. It can also contribute to the transformation.

(A) of FIG. 11 is a figure which shows an example of the coating agent apply | coated to a lens-barrel. As shown in the figure, a porous mixture 31 as a coating agent is a mixture of a porous agent 32 and a reinforcing agent 33. As described above, the porous agent 32 includes a material that forms a porous structure, and may further include a material suitable for application such as a curing agent. The reinforcing agent 33 enhances the strength of the hardness when the coating agent is cured, and is, for example, glass fiber, carbon fiber, polyamide fiber, plate-like talc, granular silica, filler, or the like. The porous mixture 31 is not limited to use as a coating agent, and may be applied to the lens barrel 3 including a porous structure.

According to the above configuration, by mixing the reinforcing agent with the porous agent, in addition to the suppression of stray light, it is possible to obtain a light and high strength strength, which can contribute to cost reduction.

The portion where the porous agent 32 is applied in the conventional lens barrel 103 may be, for example, the inner surface of the lens barrel 103 as shown in FIG. As shown, it may be the upper periphery of the opening of the lens barrel 103. The coating agent applied to the lens barrel 103 is not limited to the porous agent 32 but may be a porous mixture 31 containing a reinforcing agent. The coating agent applied to the lens barrel 103 becomes a thin film including a porous structure.

According to the above configuration, by applying the porous agent or the porous mixture according to the present invention to the conventional lens barrel, the strength (hardness) strength of the lens barrel itself can be maintained and the stray light suppressing effect can be obtained. It can be obtained and can contribute to cost reduction.

(Application method of porous agent)
A method for applying the porous agent 32 and the porous mixed agent 31 to the conventional lens barrel 103 will be described. A porous shape is formed by mixing a volatile substance or a water-soluble substance in the coating agent (porous agent 32, porous mixing agent 31), and performing heat treatment or water washing after coating. The application method is a generally known method, and examples thereof include spray coating, dip coating, and electrostatic coating.

(Another application example to a conventional lens barrel)
Another example in which the porous agent according to the present invention is used in the conventional lens barrel 103 will be described. FIG. 12A shows an example of a method for fixing a porous agent cover 32a (first structure) formed of a porous agent 32 on a conventional lens barrel 103 (second structure). FIG. The conventional lens barrel 103 (second structure) has a dense structure as compared with the porous agent cover 32a. As shown in the figure, the porous agent cover 32a covers the periphery of the opening (upper surface) and the upper side surface of the lens barrel 103, so that it is possible to obtain the effect of suppressing stray light from outside light into the lens. In addition, since the conventional lens barrel 103 can be used, it is possible to contribute to the problem of the strength of the lens barrel and the cost reduction for creating a new lens barrel.

(B) of FIG. 12 is a diagram showing an example of a method of sticking a seal-type porous agent sheet 32b (first structure) formed of a porous agent to the conventional lens barrel 103. The conventional lens barrel 103 (second structure) has a dense structure as compared with the porous agent sheet 32b. The seal-type porous agent sheet 32b is less expensive than the cover-type porous agent cover 32a, and the process of fixing to the lens barrel 103 is a simple operation of sticking, so that the workability is excellent. It can be easily performed for the purpose of repairing a wound.

The porous agent cover 32a and the porous agent sheet 32b are not limited to being formed by the porous agent 32, and may be formed by a porous agent containing a material suitable for application such as a curing agent. Alternatively, it may be formed of a porous mixture 31 mixed with a reinforcing agent.

(Example of application to light-shielding members)
FIG. 13 is a diagram showing an example in which the porous agent according to the present invention is used as a light shielding member. In FIGS. 13A and 13B, a porous agent is used for the lens barrel 103c having the lens barrel. As the application site of the porous agent, there are the rear light shielding member 34 (see FIG. 13A) on the lower surface of the lowermost lens and the inter-lens light shielding member 35 (FIG. 13B) between the lenses. .

In FIGS. 13C and 13D, a porous agent is used for the lens barrel 103d without a lens barrel. The lens barrel 103d has the functions of a lens barrel and a carrier. As the application site of the porous agent 32 to the barrelless lens barrel 103d, the rear light-shielding member 34 and the lens aperture stop member 37 (see FIG. 13C) or the fitting for bonding (adhering) the lenses together. It is a member (adhesive) 36a ((d) of FIG. 13).

The lens barrels 103c and 103d may be conventional lens barrels or lens barrels having a porous structure according to the present invention. Further, the porous agent to be used may be any material as long as it contains a material that forms a porous structure. For example, the porous agent may contain a material suitable for application, or a reinforcing agent may be mixed. Or a porous mixture. With the above configuration, stray light due to reflected light inside the lens of external light can be suppressed.

(Modified example of porous structure)
Next, FIG. 6 is a figure which shows the modification of a porous structure. 6 (a) to 6 (c) show modified examples of three types of porous structures having different forms. These modified examples show that holes penetrate vertically in the drawing. In common. According to the above configuration, since air permeability can be ensured, a moisture absorption effect, a heat suppression effect, and an internal heat deformation prevention effect are obtained. For this reason, it is possible to promote heat dissipation and prevent condensation.

In the porous structure shown in FIG. 6 (a), a substantially hemispherical recess (hole A) is formed in the upper part, and a cylindrical shape extending continuously with each of the recesses with substantially the same diameter. Hole B continues to the bottom. Although the hole diameter of the hole A is larger than the hole diameter of the hole B, in this embodiment, a structure corresponding to the fine recess structure is not observed.

Next, in the porous structure shown in FIG. 6B, a substantially hemispherical recess (hole A) is formed in the upper portion, and a plurality of holes having a hole diameter smaller than the hole A are continuously formed in each of the recesses. B's gathering continues to the bottom. Further, the collection of the numerous holes B forms the fine concavo-convex structure F described above.

Next, in the porous structure shown in FIG. 6C, a cylindrical hole A that penetrates in the vertical direction and extends with substantially the same diameter, and a cylinder that penetrates in the horizontal direction and extends with substantially the same diameter. It has a structure in which a mold hole B is formed. Although the hole diameter of the hole A is larger than the hole diameter of the hole B, in this embodiment, a structure corresponding to the fine recess structure is not observed. In addition, as shown in FIG. 6 (c), by forming a fine concavo-convex structure that penetrates the inner and outer sides of the lens barrel (in the left-right direction) to provide air permeability, Heat dissipation and condensation can be prevented.

As described above, the porous structure only needs to have a plurality of types of pores having different pore diameters, and does not necessarily have a structure corresponding to a fine concavo-convex structure.

[Embodiment 2]
Next, FIG. 1B is a diagram illustrating a configuration of the proximity sensor (optical element) 20 according to the second embodiment of the present invention. As shown in the figure, the proximity sensor 20 includes a photodiode 4, a light receiving lens (optical lens) 5, a light shielding resin (optical structure) 6, a substrate 7, and an IR-LED (light emitting element) 8. In the present embodiment, the configuration other than the porous structure formed on all or a part of the light-shielding resin 6 is not so much related to the essence of the invention. Omitted. Moreover, the structure of all the porous structures demonstrated in said Embodiment 1 is applicable to the porous structure demonstrated in this embodiment.

The proximity sensor 20 is a sensor that detects whether or not the detection target is close. As shown in the figure, the near-infrared light emitted from the IR-LED 8 is repeatedly reflected between the object to be detected and the surface of the light-shielding resin 6, and finally passes through the light-receiving lens 5 to the photodiode. 4 is incident. The light shielding resin 6 is made of a light shielding material having a property of shielding specific light (near infrared light). In the present embodiment, a porous structure is formed on all or part of the light shielding resin 6. In near-infrared devices and surveillance cameras, for example, stray light components due to multiple reflections between the light-shielding resin 6 that fills the gap between the optical lens and the light-emitting element and the cover window surface affect the detection sensitivity. According to the above configuration, since reflection of light on the surface of the light-shielding resin 6 can be suppressed, a decrease in detection sensitivity due to stray light components can be suppressed.

When the proximity sensor 20 of the present embodiment is applied to a near-infrared device and a monitoring camera, the unevenness of the fine unevenness structure F is preferably 400 nm or more and 1500 nm or less. For example, with respect to the proximity sensor 20 used for a near-infrared camera or the like, it is possible to obtain a proximity sensor 20 that can satisfactorily remove stray light components of visible light and near-infrared stray light that are not detected. Near-infrared cameras are used for vein authentication and proximity detection, as well as for monitoring purposes by illuminating an object with a near-infrared light source and transmission imaging utilizing the property of being hardly scattered. In surveillance imaging, high sensitivity is required, and in transmission imaging, it is desirable that there be less noise. In these devices, stray light has a great influence on image quality deterioration, and although transmittance control is performed by a film or the like as in a visible light camera, it is desirable that stray light outside the design can be removed as much as possible. Near-infrared is distributed in the range of approximately 700 nm to 1000 nm. By applying the fine uneven structure F with the uneven interval described above, the stray light components of the visible light and the near-infrared stray light that are not detected are satisfactorily removed.

[Embodiment 3]
Next, FIG. 5 is a diagram illustrating a configuration of mobile terminals (electronic devices) 30a and 30b according to Embodiment 3 of the present invention. As shown in the figure, the portable terminal 30a (or 30b) includes a detector 1, a lens barrel 3a (or 3b), a lens holding unit 9, the lens unit 10a described above, and lens units 10b to 10d described later, a housing A transparent component 11, a casing exterior 12, and a lens light incident part 13 are provided.

In the present embodiment, the configuration other than the porous structure formed on all or a part of the lens barrel 3a (or 3b) has little relation to the essence of the invention. Will be omitted as appropriate. Moreover, the structure of all the porous structures demonstrated in said Embodiment 1 is applicable to the porous structure demonstrated in this embodiment.

As in the lens barrels 3a and 3b, the lens barrels 3a and 3b can have different colors by forming a porous structure on all or part of the lens barrels 3a and 3b. Therefore, it is possible to create a lens barrel of a color that matches the design of the casing of the mobile terminals 30a and 30b, and it is possible to provide a product with high design.

[Embodiment 4]
Next, FIG. 7 is a diagram showing a state when the lens unit 100 of the comparative example is compared with the lens unit 10b according to Embodiment 4 of the present invention. FIGS. 7A and 7B show a state where the lens barrel 103 of the lens unit 100 of the comparative example is moved up and down. Thus, when the lens barrel 100 is moved up and down, the end portion (contact portion 103a) on the side where the light receiving element (not shown; refer to the detector 1 in FIG. 1) of the lens barrel 100 is disposed is the bottom cover 113. Contact sound may be generated.

Therefore, in the lens unit 10b of the present embodiment, as shown in FIGS. 7C and 7D, the side where the light receiving element (not shown) of the lens barrel 3 is disposed (the lower side relative to the paper surface). A porous structure is formed only in the contact portion 3a in the vicinity of the end of the contact, and the contact sound is reduced by the elastic effect due to the porosity. As described above, if the lens barrel is limited to the suppression of the contact sound of the lens barrel 3, the porous structure may be formed only in the portion that is in contact with the vertical movement.

In addition, when the lens barrel 3 is moved up and down at high speed, wind noise caused by internal air compression and vibration sound of other members are also released by the porous air permeability, leading to the suppression of sound. . If only the sound absorption effect is desired, the porous structure may not penetrate vertically (or left and right) as in the above-described modification.

[Embodiment 5]
Next, FIG. 8 is a diagram showing a structure of a lens unit 10c according to Embodiment 5 of the present invention. On the other hand, FIG. 10 is a diagram for explaining problems of the lens unit 100 of the comparative example.

As in the lens unit 100 shown in FIG. 10A, in the configuration in which the texture processing is performed around the lens opening (unevenness is formed), there is a concern that part of the scattered light reaches the detector 101 and stray light. It is incomplete as a countermeasure. On the other hand, as shown in FIG. 10B, when no processing is performed on the lens barrel 103, the reflected light from the lens opening may reach the detector 101. Considering the above points, in the lens unit 10c of the present embodiment, a porous structure is formed around the lens opening (region Q1).

In addition, as shown in the form shown on the left in the balloon in FIG. 8, the hole diameter of the holes constituting the porous structure may be increased stepwise as the lens opening is approached (for example, formed in the region Q2). The diameter of the porous hole formed in the region R2 is made larger than the diameter of the porous hole formed).

There is an apodization filter in which a low frequency contrast is increased due to the effect of reducing the aperture when a filter with small absorption at the center and greater absorption toward the periphery is installed on the exit pupil plane. According to the above configuration, the aperture diameter similar to that of the apodization filter is obtained by increasing the hole diameter of the pores constituting the porous structure as it approaches the lens aperture and controlling the transmittance distribution at the end (periphery) of the aperture. Since the transmittance distribution can be realized, an apodization effect can be easily obtained. It should be noted that when the lens barrel is formed, the apodization effect is higher as the hole diameter of the porous hole near the lens opening is larger.

[Embodiment 6]
Next, FIG. 9 is a diagram showing a structure of a lens unit 10d according to Embodiment 6 of the present invention. Usually, the light shielding property is proportional to the thickness of the substance. Therefore, in the lens unit 10d of the present embodiment, the transmittance of the lens is fixed at 1 within the range from the lens center O to the aperture radius r, and when the distance from the lens center exceeds the aperture radius r, the transmittance is increased. A porous structure around the lens opening is formed so as to decrease monotonously. For this reason, by forming the porous structure as described above around the lens opening, it is easy to control the transmittance distribution near the lens opening and to control the light-shielding properties of portions other than the lens opening. Both can be achieved.

[Summary]
The optical structure (lens barrels 3, 3a, 3b, light-shielding resin 6) according to aspect 1 of the present invention is an optical structure disposed in the vicinity of the optical lens (lens 2, light-receiving lens 5), In this configuration, a porous structure including a plurality of types of pores (A, B) having different pore diameters is formed at least in part.

According to the above configuration, the porous structure includes a plurality of types of pores having different pore diameters. Such a porous structure is easy to process and can reduce the processing cost as compared with an antireflection uneven structure by embossing (making the surface uneven). Further, according to the above configuration, the porous structure includes a hole having a large hole diameter and a hole having a small hole diameter. Here, when disturbance light is incident on the optical lens, a part thereof may become stray light and enter the optical structure. When the stray light is incident on the optical structure, it is captured by the hole having the large hole diameter. At this time, if the hole diameter of the hole having the smaller hole diameter is set to a size approximately equal to or larger than the wavelength range of the stray light, the stray light is scattered by the hole having the smaller hole diameter. For this reason, stray light captured by a hole having a large hole diameter is scattered by a hole having a smaller hole diameter, and if multiple reflections are repeated thereby, the heat energy may be lost. For this reason, part of the stray light disappears due to the porous structure, so that the stray light can be suppressed. Further, if the above-described porous structure is formed on at least a part of the optical structure, the optical structure can be reduced in weight by a porous amount compared to a dense structure having the same volume. As described above, according to the optical structure, it is possible to reduce the processing cost and reduce the weight, and to suppress stray light.

The optical structure according to Aspect 2 of the present invention is the optical structure according to Aspect 1, wherein the porous structure includes a recess (hole A) having a hole diameter capable of capturing light of a predetermined wavelength, and the recess. On the other hand, it may include a fine concavo-convex structure (F) that is continuously formed and has a concavo-convex interval smaller than the diameter of the concave portion that scatters light captured by the concave portion.

According to the above configuration, stray light is scattered by the fine concavo-convex structure if the concavo-convex spacing of the fine concavo-convex structure is set to a size approximately equal to or larger than the wavelength range of stray light. For this reason, the stray light captured by the concave portion is scattered by the fine concavo-convex structure formed continuously with respect to the concave portion, and when multiple reflections are repeated thereby, it may disappear as thermal energy. For this reason, part of the stray light disappears due to the porous structure, so that the stray light can be suppressed. In addition, the optical structure can be easily manufactured by forming the porous structure on at least a part of the optical structure, for example, so that the processing cost can be reduced. Furthermore, if the above-described porous structure is formed in at least a part of the optical structure, the optical structure can be reduced in weight by a porous amount compared to a dense structure having the same volume. As described above, according to the optical structure, it is possible to reduce the processing cost and reduce the weight, and to suppress stray light.

In the optical structure according to aspect 3 of the present invention, in the aspect 2, the recess width of the recess may be 5 μm or more, and the uneven spacing of the fine uneven structure may be 300 nm or more and 900 nm or less. According to the said structure, the optical structure from which a stray light component is removed favorably can be obtained about the optical structure used for an imaging camera etc., for example. A light receiving element used in an imaging camera or the like detects light in a wavelength range of approximately 400 to 800 nm, which is a visible light range, and has a high sensitivity characteristic at about 550 nm with high visibility. Light outside the operating wavelength range is shielded by a coating made on glass or lenses, but since the emphasis is on the intermediate band of the operating wavelength with high visibility, light at the operating wavelength end is not assumed in the design The path becomes stray light, and even if the stray light is small, it often becomes a ghost or flare depending on the situation of use, which often affects image quality degradation. Since light is scattered by a fine concavo-convex structure with concavo-convex intervals equal to or greater than the wavelength, for imaging cameras that detect visible light, by providing a concave and fine concavo-convex structure with predetermined conditions, scattering or direct concave The light guided to is repeatedly reflected by the fine concavo-convex structure formed continuously with respect to the concave portion and disappears as thermal energy.

In the optical structure according to aspect 4 of the present invention, in the aspect 2, the unevenness interval of the fine unevenness structure may be 400 nm or more and 1500 nm or less.

According to the above configuration, for example, with respect to an optical structure used for a near-infrared camera or the like, an optical structure that can satisfactorily remove stray light components of visible light and near-infrared stray light that are not detected can be obtained. Near-infrared cameras are used for vein authentication and proximity detection, as well as for monitoring purposes by illuminating an object with a near-infrared light source and transmission imaging utilizing the property of being hardly scattered. In surveillance imaging, high sensitivity is required, and in transmission imaging, it is desirable that there be less noise. In these devices, stray light has a great influence on image quality deterioration, and although transmittance control is performed by a film or the like as in a visible light camera, it is desirable that stray light outside the design can be removed as much as possible. Near-infrared is distributed in the range of approximately 700 nm to 1000 nm, and by applying the fine uneven structure with the uneven interval, the stray light component of visible light and near-infrared stray light that is not detected is satisfactorily removed.

In the optical structure according to aspect 5 of the present invention, in the aspect 1, each of the plurality of types of holes may have a diameter of 10 nm or more and 10 μm or less.

According to the above configuration, it is possible to prevent intrusion of dust, suppress distortion due to fogging or thermal expansion of the optical lens, and obtain an optical structure with high environmental resistance. The allowable size of dust is a few dozen μm, the size of water vapor is 4 nm, and the size of water droplets is 100 μm.

In the optical structure according to aspect 6 of the present invention, in any of the above aspects 1 to 5, the porous structure may be formed so as to penetrate the optical structure.

According to the above configuration, since air permeability can be ensured, a moisture absorption effect and a heat suppression effect can be obtained. For this reason, it is possible to promote heat dissipation and prevent condensation.

The optical element (lens units 10a to 10d, proximity sensor 20) according to aspect 7 of the present invention preferably includes the optical structure according to any one of aspects 1 to 6.

According to the above configuration, it is possible to realize an optical element capable of reducing processing cost and weight and suppressing stray light.

An optical element according to aspect 8 of the present invention is the optical element according to aspect 7, in which the optical element includes a lens barrel that houses the optical lens, and the porous structure is formed on the inner side of the lens barrel or the lens opening. It may be formed around.

The light incident inside the lens barrel or around the lens opening tends to be stray light. For this reason, according to the said structure, the optical element from which a stray light component is removed favorably can be provided.

An optical element according to Aspect 9 of the present invention is the optical element according to Aspect 8, wherein the porous structure has an end (contact) on the side where the light receiving element that receives light that has passed through the optical lens is disposed. It may be formed in the part 3a).

For example, when the lens barrel is moved up and down, the end of the lens barrel on the side where the light receiving element is disposed may come into contact with the bottom cover or the like, and contact noise may be generated. According to the said structure, the said contact sound can be reduced by the elastic effect by the said porous.

The optical element according to aspect 10 of the present invention is the optical element according to

aspect

8 or 9, wherein the porous structure is formed around the lens opening of the lens barrel, and the pores constituting the porous structure are formed. The hole diameter may increase as it approaches the lens opening.

For example, there is an apodization filter in which a low-frequency contrast is increased due to the effect of reducing the aperture when a filter that absorbs less in the center and increases toward the periphery is installed on the exit pupil plane. According to the above configuration, the aperture diameter similar to that of the apodization filter is obtained by increasing the hole diameter of the pores constituting the porous structure as it approaches the lens aperture and controlling the transmittance distribution at the end (periphery) of the aperture. Since the transmittance distribution can be realized, an apodization effect can be easily obtained.

The optical element according to Aspect 11 of the present invention is the optical element according to Aspect 7, wherein the optical element is a proximity sensor (20) that detects whether or not a detection target is close to the optical element. Including a light-receiving lens 5) and a light-emitting element (IR-LED 8) that emits light, and between the optical lens and the light-emitting element, shields specific light in which the porous structure is formed in whole or in part. It may be filled with a light-shielding material (light-shielding resin 6) having properties.

In near-infrared devices and surveillance cameras, for example, stray light components due to multiple reflections between the light-shielding material that fills the gap between the optical lens and the light-emitting element and the cover window surface affect the detection sensitivity. According to the above configuration, since reflection of light on the surface of the light shielding material can be suppressed, a decrease in detection sensitivity due to stray light components can be suppressed.

The electronic device (portable terminals 30a and 30b) according to the twelfth aspect of the present invention preferably includes the optical element according to any of the seventh to eleventh aspects. According to the above configuration, it is possible to realize an electronic device capable of reducing processing cost and weight and suppressing stray light.

The optical structure according to Aspect 13 of the present invention may include a reinforcing agent (33) that reinforces the hardness of the optical structure according to

Aspect

1 or 2. According to the said structure, in addition to suppression of a stray light, the intensity | strength of lightweight and high hardness can be obtained, and it can contribute also to cost reduction.

The optical structure according to the fourteenth aspect of the present invention is the optical structure according to any one of the first to fourth aspects, the first structure having the porous structure (a porous mixture 31, a porous agent 32, a porous agent cover). 32a, a porous agent sheet 32b), and a second structure (lens barrel 103) having a dense structure compared to the first structure. According to the above configuration, the strength of the lens barrel itself (hardness) can be maintained, and a stray light suppressing effect can be obtained.

An optical element according to an aspect 15 of the present invention includes the optical structure according to any one of the above aspects 1 to 5, includes a lens barrel that houses the optical lens, and a thin film (porous) including the porous structure. The porous material mixture 31 and the porous material 32) may be applied to the inner side or the upper surface side of the lens barrel. According to the above configuration, the strength (hardness) of the lens barrel itself can be maintained, and a stray light suppression effect can be obtained, which can contribute to cost reduction.

An optical element according to a sixteenth aspect of the present invention includes the optical structure according to any one of the first to fifth aspects, includes a lens barrel that houses the optical lens, and includes the porous structure. (Porous agent cover 32a) may be fixed so as to cover the upper surface and upper side surface of the lens barrel. According to the above configuration, it is possible to obtain an effect of suppressing stray light from the outside light into the lens. Further, since the conventional lens barrel can be used, it can contribute to the problem of the strength of the lens barrel and the cost reduction required for creating a new lens barrel.

An optical element according to Aspect 17 of the present invention includes a lens barrel that includes the optical structure according to any one of Aspects 1 to 5, includes a lens barrel that houses the optical lens, and includes the porous structure. (Porous agent sheet 32b) may be fixed to the upper surface of the lens barrel. According to the above configuration, the sheet is relatively inexpensive, and the process of fixing to the conventional lens barrel is a simple operation of sticking, so that it has excellent workability and is easily performed for the purpose of repairing surface scratches. Things are possible.

An optical element according to Aspect 18 of the present invention includes the optical structure according to any one of Aspects 1 to 5, wherein a plurality of the optical lenses are present, and between the plurality of optical lenses, or A lens unit having a light shielding member (inter-lens light shielding member 35, rear light shielding member 34) disposed on the lower surface of the lowermost lens among the plurality of optical lenses, and a lens barrel that houses the lens unit. In addition, the porous structure may be formed on the light shielding member. According to the said structure, the stray light by the reflected light inside the lens of external light can be suppressed.

An optical element according to Aspect 19 of the present invention is an optical element including the lens barrel that includes the optical structure according to any one of Aspects 1 to 5 and that houses the optical lens. An optical element characterized in that a quality structure is formed around a lens opening of an actuator in which a lens holding portion and the optical element are integrated or a light shielding part (lens aperture stop member 37) in the vicinity thereof. According to the said structure, the stray light by the reflected light inside the lens of external light can be suppressed.

An optical element according to aspect 20 of the present invention includes the optical structure according to any one of aspects 1 to 5, wherein a plurality of the optical lenses are present, and the plurality of optical lenses are adhesives ( An optical system comprising: a lens unit that is bonded to each other by a fitting member 36a); and a lens barrel that houses the lens unit, wherein the porous structure is formed in the adhesive. element. According to the said structure, the stray light by the reflected light inside the lens of external light can be suppressed.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

The present invention suppresses stray light to the inside of an optical lens due to reflection of external light, enables high-quality imaging, and has an easily manufactured structure, an optical element including the optical structure, and the The present invention can be applied to an electronic device provided with an optical element.

1 Detector (light receiving element)
2 Lens (optical lens)
3, 3a, 3b Lens barrel (optical structure)
5 Receiving lens (optical lens)
6 Light-shielding resin (optical structure)
8 IR-LED (Light Emitting Element)
10a to 10d Lens unit (optical element)
20 Proximity sensor (optical element)
30a, 30b Mobile terminals (electronic devices)
31 Porous agent 32 Porous agent 33 Reinforcing agent 32a Porous agent cover 32b Porous agent sheet

Claims

An optical structure disposed in the vicinity of the optical lens,
An optical structure, wherein a porous structure including a plurality of types of pores having different pore diameters is formed at least in part.
The porous structure is
A recess that is a hole having a hole diameter capable of capturing light of a predetermined wavelength;
The optical system according to claim 1, further comprising: a fine concavo-convex structure formed continuously with respect to the concave portion and having a concave and convex interval smaller than a hole diameter of the concave portion that scatters light captured by the concave portion. Structure.
3. The optical structure according to claim 1, further comprising a reinforcing agent that reinforces the hardness of the optical structure.
The optical structure according to any one of claims 1 to 3, wherein the porous structure is formed so as to penetrate the optical structure.
The first structure having the porous structure and the second structure having a dense structure as compared with the first structure are provided. The optical structure according to any one of the above.
An optical structure according to any one of claims 1 to 5, comprising:
Including a lens barrel that houses the optical lens;
An optical element, wherein the porous structure is formed inside the lens barrel or around a lens opening.
An optical structure according to any one of claims 1 to 5, comprising:
Including a lens barrel that houses the optical lens;
An optical element, wherein a thin film containing the porous structure is applied to the inner side or the upper surface side of the lens barrel.
An optical structure according to any one of claims 1 to 5, comprising:
Including a lens barrel that houses the optical lens;
An optical element, wherein a sheet including the porous structure is fixed to an upper surface of a lens barrel.
An optical structure according to any one of claims 1 to 5, comprising:
There are multiple optical lenses,
A lens unit having a light shielding member disposed between the plurality of optical lenses or on the lower surface of the lowermost lens among the plurality of optical lenses;
A lens barrel that houses the lens unit,
The optical element, wherein the porous structure is formed on the light shielding member.
The optical element according to claim 6, wherein the porous structure is formed at an end of the lens barrel on a side where a light receiving element that receives light that has passed through the optical lens is disposed. .