Manufacturing method of lens spacer and manufacturing method of lens unit

Abstract

To provide a technique that can suppress the occurrence of flare and ghosts caused by reflection of incident light on the inner wall of a spacer in a lens unit composed of a wafer level lens and the spacer.SOLUTION: A lens spacer manufacturing method is for manufacturing a lens spacer that has a through hole through which light emitted from a lens passes and has, on an end face on the lens side, an opening of the through hole and an inner wall portion, which is a wall surface of an outer edge of the opening. The lens spacer manufacturing method includes: an opening forming step of forming a molded product with a planar upper mold and a lower mold having a substantially truncated cone-shaped projection that forms the opening, and forming the opening and the inner wall surface in a first surface of the molded product; and a groove-forming step of forming a groove that extends perpendicularly to the central axis of the opening in a second surface opposite to the first surface of the molded product, and causing the groove and the opening to communicate with each other. A side surface of the projection of the lower mold has a surface roughness rougher than that of the upper mold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a lens spacer used in a wafer-level lens, and a method for manufacturing a lens unit in which a wafer-level lens and a spacer are stacked. [Background technology]

[0002] In recent years, there has been a dramatic advance in miniaturization, weight reduction, and performance improvement in electronic devices such as mobile phones, mobile computers, personal digital assistants, digital still cameras, etc. Along with these market trends, there is also a demand for smaller, thinner, and lighter lenses in the cameras mounted on electronic devices, and wafer-level lenses have come to be used.

[0003] With regard to such wafer-level lenses, it is difficult to integrally mold lenses with long focal lengths, and conventionally, a lens unit with a spacer fixed to the lens with an adhesive has been used to achieve a desired focal length.

[0004] In the lens unit described above, incident light rays are focused on an image plane to form an image of the subject. However, the trajectory of the light rays may deviate from the original design due to factors such as decentering of the lens and the aperture attached to the lens, decentering between the lens surfaces, variations in thickness, decentering of the lens unit relative to the holder, and internal reflections in the lens. As a result, particularly in lenses designed with a long focal length, light rays may strike the inner wall of the through-hole in the spacer through which the light passes. This may cause incident light to be specularly reflected by the inner wall of the through-hole in the spacer, resulting in problems such as flare or ghosting on the image plane. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 100893 Summary of the Invention [Problem to be solved by the invention]

[0006] The technology disclosed herein was invented in consideration of the above circumstances, and its purpose is to provide a technology that can suppress the occurrence of flare and ghosting in a lens unit consisting of such a wafer-level lens and a spacer, which is caused by incident light being specularly reflected on the inner wall of the through-hole of the spacer. [Means for solving the problem]

[0007] In order to solve the above-described problems, a method for manufacturing a lens spacer according to the present disclosure is a method for manufacturing a lens spacer, the lens spacer including a through hole through which light emitted from a lens passes, the through hole having an opening and an inner wall portion that is a wall surface of an outer edge of the opening, on an end surface on the lens side, an opening forming step of molding a molded product using a flat upper mold and a lower mold having a substantially truncated cone-shaped convex portion that forms the opening, and forming the opening and the inner wall surface on a first surface of the molded product; a groove forming step of forming a groove extending perpendicular to the central axis of the opening in a second surface of the molded article, the second surface being the opposite surface to the first surface, and connecting the groove and the opening; and The side surface of the convex portion of the lower mold has a surface roughness greater than the surface roughness of the upper mold.

[0008] In order to solve the above-mentioned problems, the manufacturing method of a lens spacer according to the present disclosure includes: A method for manufacturing a spacer for a lens, the spacer comprising: a through hole through which light emitted from a lens passes; and an opening of the through hole and an inner wall portion that is a wall surface of an outer edge of the opening, on an end surface of the spacer facing the lens, the method comprising: an opening forming step of molding a molded product using a flat upper mold and a lower mold having a substantially truncated cone-shaped convex portion that forms the opening, and forming the opening and the inner wall surface on a first surface of the molded product; a groove forming step of forming a groove extending perpendicular to the central axis of the opening in a second surface of the molded article, the second surface being the opposite surface to the first surface, and connecting the groove and the opening; a roughening step of roughening the surface roughness of the inner wall surface; It has.

[0009] According to these manufacturing methods, the surface roughness of the inner wall surface of the manufactured lens spacer is greater than the surface roughness of the surface opposite the lens. Therefore, light that passes through the lens and is irradiated onto the inner wall portion of the spacer is diffusely reflected or scattered by the surface with a rough surface. As a result, the light irradiated onto the inner wall portion is specularly reflected and directly incident on a sensor or the like fixed to the spacer, thereby suppressing the occurrence of flare or ghosting on the imaging surface of the sensor.

[0010] The molded article may be made of a resin material, which allows for good processability in the groove formation step and makes it possible to more reliably or easily manufacture a spacer having an inner wall surface with a rougher surface than the surface on the opposite side from the lens.

[0011] In order to solve the above-described problems, a manufacturing method of a lens unit according to the present disclosure is a manufacturing method of a lens unit formed by bonding a lens portion having a lens, and a spacer portion having a through hole through which light emitted from the lens passes, the spacer portion having an opening of the through hole and an inner wall portion that is a wall surface of an outer edge of the opening, on an end face on the lens side, a lens portion molding step of molding the lens portion; an opening forming step of forming the spacer portion using a flat upper mold and a lower mold having a substantially truncated cone-shaped convex portion that forms the opening, and forming the opening and the inner wall surface in the spacer portion; a groove forming step of forming a groove extending perpendicular to the central axis of the opening in an end surface of the spacer portion opposite to the side to which the lens portion is bonded, thereby connecting the groove and the opening; a bonding step of bonding the lens portion and the spacer portion obtained after the groove forming step by fixing them together with an adhesive; and The side surfaces of the convex portions have a surface roughness greater than the surface roughness of the upper mold.

[0012] In order to solve the above-described problems, a manufacturing method of a lens unit according to the present disclosure is a manufacturing method of a lens unit formed by bonding a lens portion having a lens, and a spacer portion having a through hole through which light emitted from the lens passes, the spacer portion having an opening of the through hole and an inner wall portion that is a wall surface of an outer edge of the opening, on an end face on the lens side, a lens portion molding step of molding the lens portion; an opening forming step of forming the spacer portion using a flat upper mold and a lower mold having a substantially truncated cone-shaped convex portion that forms the opening, and forming the opening and the inner wall surface in the spacer portion; a groove forming step of forming a groove extending perpendicular to the central axis of the opening in an end surface of the spacer portion opposite to the side to which the lens portion is bonded, thereby connecting the groove and the opening; a roughening step of roughening the surface roughness of the inner wall surface; and a bonding step of bonding the lens portion and the spacer portion after the groove forming step by fixing them together with an adhesive.

[0013] According to these manufacturing methods, the surface roughness of the inner wall surface of the spacer portion is greater than the surface roughness of the surface opposite to the side where the lens portion is bonded. Therefore, light that passes through the lens portion and is irradiated onto the inner wall surface of the spacer portion is diffusely reflected or scattered by the surface with the rough surface. As a result, the light irradiated onto the inner wall surface is specularly reflected and directly incident on a sensor or the like fixed to the spacer portion, thereby preventing flare and ghosts from occurring on the imaging surface of the sensor.

[0014] The spacer portion may be made of a resin material, which allows for good processability in the groove formation step and makes it possible to more reliably or easily manufacture a lens unit in which the surface roughness of the inner wall surface of the spacer portion is greater than the surface roughness of the surface opposite to the surface to which the lens portion is bonded.

[0015] In the bonding step, the lens portion and the spacer portion may be bonded together by being fixed with an adhesive on the radially outer side of the lens and the opening, which makes it possible to efficiently fix the lens portion and the spacer portion together without affecting the optical path of light.

[0016] In addition, in the lens portion molding step, a lens portion sheet in which a plurality of the lens portions are arranged is molded, In the opening forming step, a spacer portion sheet in which a plurality of the spacer portions are arranged is formed, and the opening and the inner wall surface of each spacer portion are formed, In the groove forming step, a plurality of grooves are formed, and the openings in the respective spacer portions are communicated with the plurality of grooves; In the bonding step, the lens portion sheet and the spacer portion sheet after the groove portion forming step are fixed together with an adhesive, thereby bonding each of the lens portions to each of the spacer portions; The method further includes a cutting step of cutting the lens portion sheet and the spacer portion sheet fixed by the adhesive into each set of the joined lens portion and spacer portion by dicing.

[0017] This makes it possible to mold many lens portions and spacer portions at once, and to manufacture many lens units at once.

[0018] In addition, in the cutting process, the lens portion sheet side of the lens portion sheet fixed with the adhesive and the spacer portion sheet after the groove forming process is attached and fixed to tape, and then dicing is performed.

[0019] This allows the lens sheet and the spacer sheet to be fixed to the tape with the spacer sheet exposed to the outside. As a result, even if chips generated during dicing adhere to the cut lens and spacer sections, the chips can be dispersed to the outside through the through holes in each spacer section, making it possible to remove the chips by spinner cleaning or the like.

[0020] In the present invention, the means for solving the above problems can be used in combination as far as possible. [Effects of the Invention]

[0021] According to the present disclosure, in a lens unit consisting of a wafer-level lens and a spacer, it is possible to suppress the occurrence of flare and ghosting caused by incident light being specularly reflected by the inner wall of the through-hole in the spacer. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of a lens unit. [Figure 2] FIG. 2 is a diagram showing another example of the structure of the contact portion between the lens portion and the spacer portion. [Figure 3] FIG. 3 is a cross-sectional view showing a state in which the lens unit is incorporated into the holder. [Figure 4] FIG. 4 is a diagram showing the shape of a mold for a spacer. [Figure 5] FIG. 5 is a diagram showing a spacer forming die and a processing method after forming. [Figure 6] FIG. 6 is a diagram showing the bonded portions of the lens sheet and the spacer sheet, the cut-out portions after bonding, and the gaps between the lenses and the spacers that are filled with adhesive. [Figure 7] FIG. 7 is a diagram showing a fixing method when cutting out a lens unit from a lens sheet and a spacer sheet, and the state of chips. [Figure 8]FIG. 8 is a diagram showing the shape of the entrance surface of the lens. [Figure 9] FIG. 9 is a diagram showing another example of the shape of the entrance surface of the lens. DETAILED DESCRIPTION OF THE INVENTION

[0023] [Example] Lens units according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the configurations and combinations thereof in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate within the scope of the gist of the present disclosure. The present disclosure is not limited by the embodiments, but is limited only by the claims.

[0024] FIG. 1 shows a lens unit 1 according to this embodiment. FIG. 1(a) is a front view of the lens unit 1 as seen from the lens side (incident side), FIG. 1(b) is a cross-sectional view of the lens unit 1 as seen from a direction perpendicular to the optical axis, and FIG. 1(c) is a rear view of the lens unit 1 as seen from the spacer side (exit side). The lens unit 1 is configured by bonding a lens section 2 including a resin wafer-level lens to a spacer section 3. By mounting a sensor S such as an imaging element on the spacer section 3, this lens unit 1 is able to focus incident light on the imaging plane of the sensor S to generate an image.

[0025] In this embodiment, the lens unit 2 has an incident surface 2a, which is a surface into which light is incident and is formed in a substantially planar shape, a lens surface 2b from which the light incident from the incident surface 2a exits, and an outer peripheral portion 2c that protrudes in an annular shape so as to surround the lens surface 2b. When the lens unit 2 and the spacer unit 3 are joined together, the outer peripheral portion 2c abuts against the spacer unit 3 and determines the distance between the lens surface 2b and the imaging plane of the sensor S. Note that the tip portion of the cross-sectional shape of the outer peripheral portion 2c is curved, which improves mold releasability during molding of the lens unit 2 and allows the outer peripheral portion 2c to stably abut against a planar front end surface 3d (described below) of the spacer unit 3.

[0026] 1(c), the spacer part 3 has an opening 3a through which light emitted from the lens part 2 passes, on the end face on the side where the spacer part 3 is bonded to the lens part 2. An inner wall part 3b is provided around the opening 3a, defining the outer edge of the opening 3a, which is formed so that its inner diameter widens toward the lens part 2. The spacer part 3 also has a groove part 3c, which is a groove-shaped recessed structure extending in a direction perpendicular to the optical axis, on the side where the sensor S is attached.

[0027] The spacer portion 3 has a front end surface 3d on the lens portion 2 side, which is the surface of the spacer portion 3. The outer peripheral portion 2c of the lens portion 2 abuts against the front end face 3d of the spacer portion 3. A gap 3e is formed on the outer periphery of the abutting portion of the front end face 3d of the spacer portion 3 and is filled with an adhesive for fixing the lens portion 2 and the spacer portion 3 in a bonded state. The surface roughness of the inner wall portion 3b around the opening 3a is set to 0.3 μm to 4 μm, which is rougher than the other surfaces of the spacer portion 3. By setting the surface roughness of the inner wall portion 3b to 0.3 μm to 4 μm, it is possible to prevent the light emitted from the lens portion 2 and specularly reflected by the inner wall portion 3b from directly irradiating the imaging surface of the sensor S and causing flare or ghosting.

[0028] The spacer portion 3 is made of a resin material, but its color is not particularly limited. It may be transparent or colored. In this case, the resin material may contain a light-blocking pigment or a dye that absorbs specific wavelengths to achieve color. More specifically, the resin material may contain carbon or titanium black, and specific wavelength-absorbing dyes such as cyanine compounds, phthalocyanine compounds, dithiol metal complexes, naphthoquinone compounds, diimmonium compounds, and azo compounds.

[0029] In the above description, the annular outer peripheral portion 2c is provided to abut against the spacer portion 3 when the lens portion 2 and the spacer portion 3 are joined, thereby defining the distance between the lens surface 2b and the imaging surface of the sensor S. However, the structure for fulfilling this function is not limited to this. For example, as shown in FIG. 2(a), multiple trapezoidal or spherical protrusions 2d (four in the example of FIG. 2(a)) may be arranged around the lens surface 2b. Furthermore, as shown in FIG. 2(b), the gap between the lens portion 2 and the spacer portion 3 may be defined using a gap control adhesive 2e containing spherical particles.

[0030] FIG. 3 is a cross-sectional view showing the lens unit 1 incorporated into a holder 4 for mounting, for example, on an imaging device (not shown). The holder 4 has, for example, a prismatic or cylindrical outer shape and, as shown in FIG. 3(a), has a storage chamber 4c therein, which is a space for storing the lens unit 1. The lens unit 1 and the sensor S are fixed to the ceiling surface of the storage chamber 4c, and the base 4a is further fixed to the holder 4 so as to close the storage chamber 4c of the holder 4, thereby storing the lens unit 1 within the storage chamber 4c. The top surface of the holder 4 is provided with an entrance hole 4b through which incident light is incident. This entrance hole 4b has a portion with a minimum diameter halfway along the optical axis, which functions as an aperture. Note that the shape of the holder 4 described above is merely an example and is not particularly limited.

[0031] Here, incident light that enters lens unit 1 normally enters through entrance hole 4b in holder 4, passes through lens section 2 and opening 3a in spacer section 3, and is collected on the imaging surface of sensor S to form an image. However, due to the effects of manufacturing variations such as decentering of entrance hole 4b and lens section 2, inter-face decentering of lens section 2, thickness differences, and decentering of lens section 2 and holder 4, as well as the effects of internal reflection in lens section 2, incident light rays may deviate from the original design. As a result, in lens section 2 designed with a particularly long focal length, light rays may hit inner wall section 3b of spacer section 3.

[0032] In this case, undesigned light rays may be specularly reflected by the inner wall 3b of the spacer portion 3 and irradiated onto the sensor S, resulting in flare or ghosting. In contrast, in this embodiment, the surface roughness of the inner wall 3b of the spacer portion 3 is set to 0.3 μm to 4 μm, which is rougher than the other surfaces of the spacer portion 3. As a result, even if undesigned light rays hit the inner wall 3b of the spacer portion 3, they are diffusely reflected or scattered, as shown in FIG. 3(b), thereby preventing the light rays from being specularly reflected and directly irradiated onto the sensor S. As a result, it is possible to suppress the occurrence of flare and ghosting.

[0033] Table 1 below shows the results of an experiment showing the relationship between the surface roughness of the inner wall portion 3b and the occurrence of flare. [Table 1] *1. If a flare occurs, mark it as ×, and if no flare occurs, mark it as 〇. Thus, it was found that the occurrence of flare can be suppressed by setting the surface roughness of the inner wall portion 3b to 0.3 μm or more and 4 μm or less. For flare evaluation, a ghost flare evaluation system GCS-2T (manufactured by Tsubosaka Electric Co., Ltd.) was used, and incident light with a half angle of view of 47.5 degrees was made incident from the object plane, and the occurrence of flare was evaluated visually from the image.

[0034] <Wafer-level lens manufacturing method> Next, a method for manufacturing the lens portion 2 and the spacer portion 3 in this embodiment will be described. The lens portion 2 in this embodiment is obtained by molding a curable composition (resin material) by imprint molding or injection molding. The material of the molding die used to mold the lens portion 2 is not particularly limited, and may be, for example, metal, glass, plastic, or the like.

[0035] Examples of methods for molding the lens portion 2 include: (1) Step 1: preparing a lens molding die (not shown) having one or more lens shapes; (2) Step 2: after Step 1, bringing a curable composition into contact with or injecting it into the lens molding die; and (3) Step 3: after Step 2, curing the curable composition by heating and / or light irradiation. When heat treatment is performed in Step 3, the temperature can be adjusted appropriately depending on the components and catalyst used in the reaction, and is not particularly limited, but may be, for example, about 100 to 200°C. When light irradiation is performed in Step 3, the light source can be, for example, a UV-LED, a mercury lamp, a xenon lamp, a carbon arc lamp, a metal halide lamp, sunlight, an electron beam source, a laser light source, or the like.

[0036] The above molding method may further include (4) Step 4: Annealing the cured curable composition after Step 3. The details of this annealing are not particularly limited, but may be carried out, for example, by heating at a temperature of 100 to 200°C for about 30 minutes to 1 hour. The annealing can be carried out after removing the lens molding die, or it can be carried out without removing it.

[0037] In the above molding method, typically, step 3 or step 4 may produce a sheet-like cured product (lens sheet 22) in which one or more lens portions 2 are formed in a connected state. This lens sheet 22 corresponds to the lens portion sheet in the present disclosure. When the lens sheet 22 has a plurality of lens portions 2, these lens portions 2 may be arranged regularly (aligned) or randomly. The lens portion 2 shown in FIG. 1 can be obtained by cutting the lens sheet 22 by dicing and removing excess portions. That is, after step 3 or step 4, step 5: a step of cutting the cured curable composition (lens sheet 22) may be further included. The cured curable composition of the present invention can be cut by known or conventional processing means. The above-mentioned method for producing a wafer-level lens corresponds to the lens portion molding step in the present disclosure.

[0038] <Spacer manufacturing method> Next, a method for manufacturing the spacer portion 3 will be described. The spacer portion 3 is made of a material similar to the lens portion 2. The curable composition is produced by the steps corresponding to the above-mentioned steps 1 to 5, which are the molding steps of the curable composition. Here, explanations of steps corresponding to steps 1 to 5 will be omitted. The spacer portion 3 may be formed by imprint molding. Fig. 4 shows the shape of a lower mold 11 for forming the front end surface 3d side of the spacer portion 3. Similar to the molding of the lens portion 2 described above, this lower mold 11 has an array of protrusions 11a that form openings 3a of the spacer portion 3 in order to mold a plurality of spacer portions 3 as the spacer sheet 23.

[0039] The protrusion 11a has a generally conical shape with a diameter decreasing toward the top in the figure and a flat top end 11b. The inner wall 3b of the spacer portion 3 is formed by a slope 11c on the side of the protrusion 11a. As shown in FIG. 4(b), the surface roughness of the slope 11c is previously roughened by blasting. Furthermore, the top end 11b of the protrusion 11a is polished after blasting to adjust the surface roughness to be smaller than that of the slope 11c. This is a measure to facilitate demolding of the lower mold 11 after molding. The protrusion 11a corresponds to the convex portion in this disclosure.

[0040] FIG. 5(a) shows the arrangement of the lower mold 11 and upper mold 12 for molding a sheet-like cured product (spacer sheet 23) formed with one or more lens portions 2 connected together. As described above, the lower mold 11 has the same number of protrusions 11a as the number of spacer portions 3 to be molded at one time. On the other hand, the upper mold 12 has a planar mold surface. FIG. 5(b) shows the spacer sheet 23 molded by the lower mold 11 and upper mold 12. After molding is complete, the spacer sheet 23 has a sheet-like molded product with a planar upper side and multiple recesses 23a that will become openings 3a and inner wall portions 3b formed on the lower side. The spacer sheet 23 corresponds to the spacer portion sheet in this disclosure. The process of molding the spacer sheet 23 with the lower mold 11 and upper mold 12 corresponds to the opening molding process in this disclosure. Then, the spacer sheet 23 is half-cut from above by dicing to form grooves 23b that will become groove portions 3c, and the grooves 23b and the recesses 23a are connected to form holes 23c that penetrate from the top to the bottom of the spacer sheet 23. After cutting, these holes 23c become through holes in the spacer portions 3. This process corresponds to the groove forming process in the present disclosure. The lower surface of the spacer sheet 23 corresponds to the first surface in the present disclosure. The upper surface of the spacer sheet 23 corresponds to the second surface in the present disclosure.

[0041] After the lens sheet 22 and the spacer sheet 23 are molded, the lens sheet 22 and the spacer sheet 33 are fixed together with an adhesive (e.g., a UV-curable adhesive) so that the optical axis of each lens coincides with the central axis of each hole 23c, and then cut by dicing to cut out a plurality of lens units 1. Figure 6(a) shows fixing points 14 when the molded lens sheet 22 and spacer sheet 23 are fixed together with an adhesive, and a cutter trajectory 15 when the bonded lens sheet 22 and spacer sheet 23 are cut by dicing. This process corresponds to the bonding process and cutting process in this disclosure.

[0042] In FIG. 6(a), the hatched dashed circles indicate the adhesive fixing points 14. The thick dashed vertical and horizontal lines indicate the cutter trajectory 15. As shown in FIG. 6(a), the adhesive only needs to be applied to the four corners of the portion that will become the lens unit 1. FIG. 6(b) shows a cross-sectional view of the lens portion 2, spacer portion 3, and adhesive 14a in the lens unit 1 after cutting. As shown in FIG. 6(b), a gap 3e is formed outside the contact portion between the outer periphery 2c of the lens portion 2 and the front end face 3d of the spacer portion 3, so that the adhesive 14a can be filled between the lens portion 2 and the spacer portion 3. The height of this gap 3e is 10 μm to If the thickness is within the range of 500 μm, a sufficient amount of adhesive 14a can be filled in. Here, the lens unit 1 after being cut out corresponds to a set of a lens portion and a spacer portion in the present disclosure.

[0043] When the lens sheet 22 and the spacer sheet 23 are cut out by dicing, the lens sheet 22 and the spacer sheet 23 are attached and fixed to tape 17 as shown in the upper views of Figures 7(a) and (b) before dicing. At this time, there are cases where the spacer sheet 23 side is attached to tape 17 as shown in the upper view of Figure 7(a) or where the lens sheet 22 side is attached to tape 17 as shown in the upper view of Figure 7(b). However, when the spacer sheet 23 side is attached to tape 17 as shown in the upper view of Figure 7(a), chips C generated during dicing may adhere to the surface of lens surface 2b as shown in the lower view of Figure 7(a).

[0044] In this case, because chips C exist in the space covered by lens surface 2b, it is difficult to remove them, for example, even if lens sheet 22 and spacer sheet 23 are cleaned by spinner cleaning. On the other hand, when lens sheet 22 is attached to tape 17, chips C generated by dicing exist in a space open to the outside, as shown in the lower diagram of Figure 7(b), and therefore chips C can be removed by spinner cleaning, for example.

[0045] In addition, in this embodiment, the area of ​​the incident surface 2a of the lens portion 2 on the outer periphery of the lens surface 2b is made to have a substantially flat shape as shown in Fig. 8(a), and therefore it is possible to ensure sufficient strength when attaching it to tape 17. If the incident surface 2a of the lens portion 2 has an uneven structure as shown in Fig. 8(b), the contact area with tape 17 would be small, making it difficult to obtain sufficient strength.

[0046] It is not necessary for the entire incident surface 2a of the lens portion 2 to be flat. For example, as shown in Fig. 9(a), if the area on the outer periphery of the incident surface 2a is flat and the area corresponding to the central lens surface 2b of the incident surface 2a is concave, sufficient strength can be ensured when attaching it to tape 17. On the other hand, as shown in Fig. 9(b), if the area on the outer periphery of the incident surface 2a is flat and the area corresponding to the central lens surface 2b of the incident surface 2a is convex, the contact area with tape 17 is small, making it difficult to obtain sufficient strength, as in the case shown in Fig. 8(b).

[0047] In the above example, it is assumed that the inclined surface 11c of the lower mold 11 in the molding die is subjected to a blasting treatment in advance to selectively roughen the surface of the inner wall portion 3b during molding of the spacer portion 3. However, in the present invention, the blasting treatment may be performed on the entire spacer sheet 23 after molding the spacer sheet 23 with the molding die or after processing the groove portion 3c by half-cutting during dicing. This allows the surface roughness to be increased over a wider area of ​​the spacer portion 3, making it possible to more reliably suppress flare and ghosting. In this case, the process of performing a blasting treatment on the entire spacer sheet 23 corresponds to the roughening process in this disclosure.

[0048] Furthermore, in the above embodiment, when forming the grooves 3c by half-cutting in dicing, the surface roughness of the grooves 3c may be set to 0.3 μm or more and 4 μm or less by appropriately selecting the abrasive grains of the cutter. This allows the surface roughness of not only the inner wall 3b but also the grooves 3c to be roughened, and light that has passed through the lens unit 2 is specularly reflected over the entire area of ​​the through hole of the spacer unit 3, thereby making it possible to suppress the occurrence of flare and ghosts in the sensor S.

[0049] Although embodiments of the lens unit according to the present disclosure have been described above, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. [Explanation of symbols]

[0050] 1. Lens unit 2. Lens section 2a...Incidence surface 2b Lens surface 2c...Outer periphery 3. Spacer part 3a...Aperture 3b...Inner wall part 3c...Groove 3e...Void part 4. Holder 4a···bass 11...Lower mold 11a...Protrusion 12...upper mold 22 Lens sheet 23 Spacer sheet

Claims

1. A method for manufacturing a spacer for a lens, the spacer comprising: a through hole through which light emitted from a lens passes; and an opening of the through hole and an inner wall portion that is a wall surface of the opening, on an end surface of the spacer facing the lens, the method comprising: an opening forming step of molding a molded product using a flat upper mold and a lower mold having a substantially truncated cone-shaped convex portion that forms the opening, and forming the opening and the inner wall portion on a first surface of the molded product; a groove forming step of forming a groove extending perpendicular to the central axis of the opening in a second surface of the molded article, the second surface being the opposite surface to the first surface, and connecting the groove and the opening; and A method for manufacturing a lens spacer, wherein the side surface of the convex portion of the lower mold has a surface roughness greater than the surface roughness of the upper mold.

2. A method for manufacturing a spacer for a lens, the spacer comprising: a through hole through which light emitted from a lens passes; and an opening of the through hole and an inner wall portion that is a wall surface of the opening, on an end surface of the spacer facing the lens, the method comprising: an opening forming step of molding a molded product using a flat upper mold and a lower mold having a substantially truncated cone-shaped convex portion that forms the opening, and forming the opening and the inner wall portion on a first surface of the molded product; a groove forming step of forming a groove extending perpendicular to the central axis of the opening in a second surface of the molded article, the second surface being the opposite surface to the first surface, and connecting the groove and the opening; a roughening step of roughening the surface roughness of the inner wall portion; A method for manufacturing a lens spacer, comprising:

3. The method for manufacturing a lens spacer according to claim 1 or 2, wherein the molded product is made of a resin material.

4. A method for manufacturing a lens unit formed by bonding a lens part having a lens, and a spacer part having a through hole through which light emitted from the lens passes, the spacer part having an opening of the through hole and an inner wall part that is a wall surface of the opening on an end face on the lens side, the method comprising: a lens portion molding step of molding the lens portion; an opening forming step of forming the spacer portion using a flat upper mold and a lower mold having a substantially truncated cone-shaped convex portion that forms the opening, and forming the opening and the inner wall portion in the spacer portion; a groove forming step of forming a groove extending perpendicular to the central axis of the opening in an end surface of the spacer portion opposite to the side to which the lens portion is bonded, thereby connecting the groove and the opening; a bonding step of bonding the lens portion and the spacer portion obtained after the groove forming step by fixing them together with an adhesive; and A method for manufacturing a lens unit, wherein the side surface of the convex portion has a surface roughness greater than the surface roughness of the upper mold.

5. A method for manufacturing a lens unit formed by bonding a lens part having a lens, and a spacer part having a through hole through which light emitted from the lens passes, the spacer part having an opening of the through hole and an inner wall part that is a wall surface of the opening on an end face on the lens side, the method comprising: a lens portion molding step of molding the lens portion; an opening forming step of forming the spacer portion using a flat upper mold and a lower mold having a substantially truncated cone-shaped convex portion that forms the opening, and forming the opening and the inner wall portion in the spacer portion; a groove forming step of forming a groove extending perpendicular to the central axis of the opening in an end surface of the spacer portion opposite to the side to which the lens portion is bonded, thereby connecting the groove and the opening; a roughening step of roughening the surface roughness of the inner wall portion; a bonding step of bonding the lens portion and the spacer portion obtained after the groove forming step by fixing them together with an adhesive; A method for manufacturing a lens unit comprising the steps of:

6. The method for manufacturing a lens unit according to claim 4 or 5, wherein the spacer portion is made of a resin material.

7. The method for manufacturing a lens unit according to claim 4 , wherein in the bonding step, the lens portion and the spacer portion are bonded together by being fixed with an adhesive at radially outer sides of the lens and the opening.

8. In the lens portion molding step, a lens portion sheet in which a plurality of the lens portions are arranged is molded, In the opening forming step, a spacer portion sheet in which a plurality of the spacer portions are arranged is formed, and the opening and the inner wall portion are formed in each spacer portion, In the groove forming step, a plurality of grooves are formed, and the openings in the respective spacer portions are communicated with the plurality of grooves; In the bonding step, the lens portion sheet and the spacer portion sheet after the groove portion forming step are fixed together with an adhesive, thereby bonding each of the lens portions to each of the spacer portions; 8. The method for manufacturing a lens unit according to claim 4, further comprising a cutting step of dicing the lens portion sheet and the spacer portion sheet fixed with the adhesive into each pair of joined lens portion and spacer portion.

9. 9. The lens unit according to claim 8, wherein in the cutting step, the lens portion sheet side of the lens portion sheet fixed with the adhesive and the spacer portion sheet after the groove forming step are attached and fixed to a tape, and then dicing is performed. Manufacturing method of

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