Mold, lens, lens unit, information terminal, image pickup apparatus, and molding method

Abstract

Provided is a mold, a lens, a lens unit, an information terminal, an imaging device, and a molding method, the lens including a first optically effective surface and a second optically effective surface intersecting an optical axis, wherein at least one of the first optically effective surface and the second optically effective surface has an inflection point between an intersection with the optical axis and an effective region end portion; a distribution of a thickness between the first optically effective surface and the second optically effective surface in a direction parallel to the optical axis has an extreme value at a position away from the optical axis in a direction perpendicular to the optical axis; the at least one has a surface roughness at a first portion that is greater than a surface roughness of a second portion that is thicker than the first portion; and a difference between the surface roughness of the first portion and the surface roughness of the second portion is 1.0 nm Ra or greater in terms of arithmetic mean roughness.

Description

Technical Field

[0001] This disclosure relates to molds, lenses, lens units, information terminals, camera equipment, and molding methods. Background Technology

[0002] In recent years, with the increase in magnification and miniaturization of camera equipment, there has been a demand for high precision and miniaturization of optical components, and aspherical lenses with inflection points within the effective diameter (hereinafter referred to as "gull lenses") have been adopted. Japanese Patent Application Publication No. 2015-26946 discloses a gull lens.

[0003] One method for manufacturing aspherical lenses made of glass involves pressing a mold onto molten glass material to create a lens of a desired shape. However, when forming aspherical lenses, there is a concern that stress may concentrate on a portion of the lens upon demolding, potentially causing the lens to break.

[0004] Japanese Patent Application Publication No. 2007-99598 discloses a mold that reduces lens cracking during molding by making the surface roughness of the central part of the mold less than that of other parts when molding a glass lens whose curvature varies greatly between the central part and other parts.

[0005] Aspherical lenses with an inflection point within their effective diameter offer potential for improvement in optical properties. Furthermore, when manufacturing aspherical lenses with an inflection point within their effective diameter using a mold formed on glass, the lenses tend to break depending on their shape. Summary of the Invention

[0006] Therefore, according to a first aspect of this disclosure, a technique is provided that can improve the optical properties of an aspherical lens. Furthermore, according to a second aspect of this disclosure, a technique is provided that can suppress cracking during the forming of an aspherical lens.

[0007] A first aspect of this disclosure is a lens comprising a first optically effective surface and a second optically effective surface intersecting an optical axis, wherein at least one of the first and second optically effective surfaces has an inflection point between the intersection with the optical axis and an end of an effective region; the thickness distribution between the first and second optically effective surfaces in a direction parallel to the optical axis has an extreme value at a position away from the optical axis in a direction perpendicular to the optical axis; at least one of the first and second optically effective surfaces has a surface roughness at a first portion of the lens that is greater than the surface roughness of a second portion, the second portion being thicker than the first portion; and the difference between the surface roughness of the first portion and the surface roughness of the second portion has an arithmetic mean roughness equal to or greater than 1.0 nmRa.

[0008] A second aspect of this disclosure is a mold comprising: a pair of first and second components for press-forming a lens having a first and a second optically effective surface intersecting an optical axis, wherein at least one of the first and second optically effective surfaces has an inflection point between the intersection with the optical axis and an effective region end, and wherein the thickness distribution between the first and second optically effective surfaces in a direction parallel to the optical axis has an extreme value at a position away from the optical axis in a direction perpendicular to the optical axis, wherein at least one of the first and second components has a surface roughness at a first corresponding portion corresponding to a first portion of the lens that is greater than the surface roughness of a second corresponding portion corresponding to a second portion of the lens, the second portion of the lens being thicker than the first portion.

[0009] The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is illustrated by way of example. Attached Figure Description

[0010] Figure 1 This is a diagram illustrating an example of a lens according to Embodiment 1 of the present disclosure and an example of the thickness distribution of the lens.

[0011] Figure 2 This is a schematic diagram illustrating a method of forming a lens using a mold according to Embodiment 1 of this disclosure.

[0012] Figure 3 This is a diagram illustrating the measurement locations of the surface roughness of the mold according to Embodiment 1 of this disclosure.

[0013] Figure 4A This is a diagram illustrating an example of the surface roughness of a mold according to Embodiment 1 of this disclosure.

[0014] Figure 4B This is a diagram illustrating an example of the surface roughness of a mold according to Embodiment 1 of this disclosure.

[0015] Figure 4C This is a diagram illustrating an example of the surface roughness of a mold according to Embodiment 1 of this disclosure.

[0016] Figure 4D This is a diagram illustrating an example of the surface roughness of a mold according to Embodiment 1 of this disclosure.

[0017] Figure 5 This is a diagram illustrating an example of a lens unit according to Embodiment 2 of this disclosure.

[0018] Figure 6 This is a diagram illustrating an example of an information terminal according to Embodiment 3 of this disclosure.

[0019] Figure 7 This is a diagram illustrating an example of a camera device according to Embodiment 4 of this disclosure. Detailed Implementation

[0020] Further features of this disclosure will become apparent from the following description of exemplary embodiments and examples with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative positions of components described in the following embodiments and examples are freely customizable and can be varied depending on the configuration of the device to which this disclosure is applied or various conditions. Additionally, the same reference numerals are used in the drawings to denote the same or functionally similar elements. (Example 1) [Lens Configuration]

[0021] Reference Figure 1 A lens according to Embodiment 1 of this disclosure is described. The lens has two optically effective surfaces (a first optically effective surface and a second optically effective surface), each intersecting the optical axis. One of these two optically effective surfaces is the light-incident surface and the object-side optically effective surface, and is referred to as the object-side surface. The other optically effective surface is the light-exit surface and the image-side optically effective surface, and is referred to as the image-side surface. The entire surface of the optically effective surface is the effective region through which the effectively imaged light rays pass. The effective region end of the lens refers to the end of the optically effective region of the lens, and the optically effective region of the lens refers to the region of the lens having predetermined optical characteristics. The light-incident surface or the light-exit surface of the lens may have ineffective regions through which non-imaged light rays pass. The surface of the lens may have ineffective regions through which light rays do not pass in the optical system. The boundary between the effective region and the ineffective region is the effective region end.

[0022] The lens according to Example 1 can be molded and can be a glass lens made of materials such as borosilicate glass, lanthanum glass, or fluorophosphate glass. The lens according to this embodiment can be molded and can be a plastic lens made of materials such as cyclic olefin polymers, polycarbonate, or acrylic resins.

[0023] The lens according to this embodiment can be formed as a so-called gull-shaped lens with an inflection point in its effective diameter. Specifically, the gull-shaped lens has an inflection point on at least one of the contour lines of the lens cross-section, including the optical axis and along the optical axis, between the end of the effective region of the lens and the intersection of the contour line and the optical axis. That is, at least one of the object-side surface and the image-side surface has an inflection point between the end of the effective region and the intersection with the optical axis. In the gull-shaped lens, the distribution of thickness between the object-side surface and the image-side surface in a direction parallel to the optical axis (optical axis direction) has an extreme value at a position away from the optical axis in a direction perpendicular to the optical axis (radial direction) (i.e., positions other than the intersection between the lens and the optical axis). The position with the extreme value is called the extreme value position. That is, the relationship (function) of thickness at the position relative to the position in the radial direction has an extreme value of thickness at the extreme value position.

[0024] Figure 1 (a) shows an example of a lens according to Embodiment 1, and Figure 1 (b) shows an example of the thickness distribution of the lens according to Embodiment 1. Figure 1 As shown in (a), the lens 1 according to Embodiment 1 has inflection points 102 and 103 at the image-side contour line of the lens section including and along the optical axis, between the effective region ends 104 and 105 of the lens and the intersection point 101 between the contour line and the optical axis. Furthermore, in the lens 1, as... Figure 1 As shown in (b), the thickness distribution 110 between the object-side surface and the image-side surface in the direction parallel to the optical axis has extreme points 112 and 113, except for point 111 which corresponds to the intersection between the lens and the optical axis. Figure 1 (b) also shows the effective region endpoints 114 and 115 of the thickness distribution 110 corresponding to the effective region endpoints 104 and 105.

[0025] Note that the configuration of lens 1 is an example, and the lens according to embodiment 1 may have an inflection point at the end of the effective area of ​​the lens and between the intersection of the contour line and the optical axis on the object side of the lens section that includes the optical axis and runs along the optical axis. Furthermore, in Figure 1In lens 1 shown in (a), the image-side surface has a concave shape near the center and the object-side surface has a convex shape. However, the shape of the lens according to embodiment 1 is not limited to this. In the lens according to embodiment 1, the image-side surface may have a convex shape near the center and the object-side surface may have a concave shape, wherein the surfaces on both sides may have a concave shape or the surfaces on both sides may have a convex shape.

[0026] Furthermore, in lens 1, the surface roughness of at least one of the object-side surface and the image-side surface in a relatively thin portion of lens 1 is greater than the surface roughness in other portions. In other words, the surface roughness of at least one of the object-side surface and the image-side surface in the first portion of lens 1 is greater than the surface roughness in the second portion, which is thicker than the first portion.

[0027] Shapes with large surface roughness are considered, such as shapes with large arithmetic mean roughness on the surface and shapes with high spatial frequencies and extreme values ​​of power spectral density (PSD) on the surface. When the evaluation metric is Ra, the measurement range centered on the corresponding point is set as the area used to measure the surface roughness. The measurement range is preferably 10 μm or greater, 25 μm or greater, or 60 μm or greater, and more preferably 1000 μm or less, 600 μm or less, or 250 μm or less. When the evaluation metric is PSD, the measurement area is preferably 600 μm centered on the corresponding point. 2 Above and 0.06mm 2 The following is a square area. However, it is not limited to this; a 100μm area centered on the corresponding point can be used. 2 Up to 0.01mm 2 or 0.01mm 2 Up to 1mm 2 Surface roughness within a square region.

[0028] Power spectral density is a spectral function that expresses roughness as a power value per unit frequency width so as to be independent of frequency decomposition Δf. In this specification, power spectral density (PSD) is expressed in logarithmic terms. This specification describes the spatial frequencies of the extrema of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm]. However, the spatial frequency range of PSD associated with the extrema is not limited to spatial frequencies of 6000 [1 / mm] to 10000 [1 / mm] and can be varied according to the desired configuration.

[0029] Therefore, lens 1 may, for example, be configured such that the arithmetic mean roughness of at least one of the object-side surface and the image-side surface in a relatively thin portion of lens 1 is greater than the arithmetic mean roughness in other portions. Lens 1 may also, for example, be configured such that the surface roughness is based on power spectral density, and in the spatial frequencies of 6000 [1 / mm] to 10000 [1 / mm] represented by power spectral density, the spatial frequency of the extreme values ​​of power spectral density in a relatively thin portion of lens 1 is higher than the spatial frequency of the extreme values ​​of power spectral density in other portions.

[0030] In gull-shaped lenses with large thickness variations, there is a concern that optical properties may deteriorate due to the expansion of the light distribution, which is caused by the Lambert-Beer law, where the absorption of transmitted light is greater in thicker portions and less in thinner portions. In lens 1 according to Embodiment 1, scattering is less in the thicker portions due to their lower surface roughness. Therefore, the reduction in transmitted light intensity is smaller in the thicker portions compared to the thinner portions with larger surface roughness, and the expansion of the light distribution on the lens surface can be suppressed. In this regard, a significant difference in surface roughness between the portions to be compared (the first and second portions) within an optically effective surface can be 1.0 nmRa or greater, according to the arithmetic mean roughness. From the viewpoint of suppressing the expansion of the light distribution on the optically effective surface, two portions with a surface roughness difference of less than 1.0 nmRa within an optically effective surface are not effective. A significant difference in surface roughness between the portions to be compared (the first and second portions) within an optically effective surface can be 10 nmRa or less, according to the arithmetic mean roughness. If the difference in surface roughness, measured by the arithmetic mean roughness, exceeds 10 nmRa, the degrees of freedom for lens design to achieve the desired optical properties can be reduced.

[0031] Furthermore, when using a mold for press molding of a gull-shaped lens with a large thickness variation, there is a concern that stress tends to accumulate in a portion of the lens during demolding due to the difference in thermal shrinkage proportional to the lens thickness, potentially leading to breakage. In lens 1 according to Embodiment 1, during press molding, the high surface roughness in the thinner portion accelerates the demolding process. By accelerating the demolding process in the thinner portion of lens 1, the demolding process of lens 1 can be controlled, sudden stress changes during molding can be suppressed, and breakage of lens 1 during molding can be prevented. Methods for shaping glass lenses

[0032] Next, we will refer to Figure 2Describes a mold for heating and softening glass components and for pressing and shaping glass components, as well as a method for shaping glass lenses. Figure 2 This is a schematic diagram illustrating a molding method using the mold according to Example 1.

[0033] According to Embodiment 1, the mold 4 includes a first component 2 and a second component 3. The first component 2 and the second component 3 are mold components for transferring the shape of the optically effective surface of the lens 1 to be formed, and the components are cylindrical in shape. Therefore, the lens 1 formed using the mold 4 can have a shape corresponding to the shape of the first component 2 and the second component 3 that contact the lens 1 during forming. For example, the lens 1 formed using the mold 4 can have a surface roughness corresponding to the surface roughness of the first component 2 described below on the surface that contacts the first component 2 during forming. Similarly, the lens 1 formed using the mold 4 can have a surface roughness corresponding to the surface roughness of the second component 3 described below on the surface that contacts the second component 3 during forming. The first component 2 and the second component 3 can be formed using, for example, a cemented carbide as a material to suppress mold wear. Furthermore, a material harder than cemented carbide can be formed on the surfaces of the first component 2 and the second component 3. Note that the component shapes of the first component 2 and the second component 3 are not limited to cylindrical shapes and can be any shape corresponding to the desired configuration.

[0034] The mold 4 has a drive system (not shown) and can form the lens 1 by moving at least one of the first member 2 and the second member 3 in a vertical direction during pressure forming. Here, the pressure forming method is described as an example of a method for forming the lens 1 using the mold 4 according to Embodiment 1. Note that the following forming method is merely an example, and the lens 1 can be formed by any known forming method capable of forming the shape of the two surfaces of the lens using the mold members.

[0035] In the molding method according to Embodiment 1, firstly, the mold 4 is heated, and then a preform of the lens 1 is arranged in the mold 4. Then, the mold 4 and the preform are further heated to soften the preform until its viscosity becomes suitable for pressure molding. Next, at least one of the first member 2 and the second member 3 is moved vertically to pressurize the preform, and the mold 4 is brought into contact with the preform to mold it into the desired shape of the lens 1. Finally, the temperature of the mold 4 is lowered, and when the temperature of the mold 4 becomes below a predetermined temperature, the applied load is unloaded. When the load is unloaded, the pressurized lens 1 may deform, and the lens 1 can be released from the mold 4.

[0036] At least one of the first component 2 and the second component 3 has a surface roughness at a portion corresponding to a relatively thin part of the lens 1 that is greater than the surface roughness of other portions of the at least one component. In other words, the at least one component has a surface roughness at a portion (first corresponding portion) corresponding to a first part of the lens 1 that is greater than the surface roughness of a portion (second corresponding portion) corresponding to a second part that is thicker than the first part of the formed lens 1. The portion of the at least one of the first component 2 and the second component 3 that corresponds to a portion of the lens 1 (e.g., a relatively thin part of the formed lens 1) may be a portion that contacts that portion of the lens 1 when the lens 1 is formed. Here, the difference between the surface roughness of the first corresponding portion and the surface roughness of the second corresponding portion can be 1.0 nmRa or greater, calculated by arithmetic mean. The difference between the surface roughness of the first corresponding portion and the surface roughness of the second corresponding portion can be 10 nmRa or less, calculated by arithmetic mean.

[0037] More specifically, according to Embodiment 1, at least one of the first component 2 and the second component 3 has a surface roughness at a portion corresponding to the point with the smallest thickness of the glass lens in a point group in the thickness distribution of the glass lens, which is greater than the surface roughness at the portion corresponding to the point with the largest thickness of the glass lens in the point group, which includes a point corresponding to the intersection between the glass lens and the optical axis, an effective region endpoint, and a point with an extreme value.

[0038] With this configuration, in the mold 4 according to Embodiment 1, when the lens 1 is pressurized and formed, the demolding process is accelerated due to the large surface roughness at the portion corresponding to the thin part of the lens 1. By accelerating the demolding process at the thin part of the lens 1, the demolding process of the lens 1 can be controlled, sudden changes in stress during forming can be suppressed, breakage of the lens 1 during forming can be suppressed, and a glass lens with suppressed light distribution expansion can be manufactured.

[0039] At least one of the first component 2 and the second component 3 may, for example, have an arithmetic mean roughness at a portion corresponding to a relatively thin portion of the lens 1 that is greater than the arithmetic mean roughness of the other portions of the at least one component. The surface roughness of the portion of the at least one component may be configured such that, for example, in a spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] expressed in terms of power spectral density, the spatial frequency of the extreme value of the power spectral density at the portion corresponding to the relatively thin portion of the lens 1 is higher than the spatial frequency of the extreme value of the power spectral density at the other portions of the at least one component.

[0040] The surface roughness of at least one of the first component 2 and the second component 3 can be changed in stages. For example, the surface roughness of at least one of the first component 2 and the second component 3 can be changed in two stages: at the portion corresponding to the relatively thin part of the lens 1 after molding, and at the portion other than that portion (the other portions). The surface roughness of at least one of the first component 2 and the second component 3 can be changed in three or more stages. Since the surface roughness of the mold component changes in stages according to the thickness of the lens 1 after molding, the timing of the demolding process can be controlled more appropriately. As a result, sudden changes in stress during molding can be suppressed, the occurrence of cracks in the glass lens can be suppressed, and a glass lens with suppressed light distribution propagation can be manufactured.

[0041] Furthermore, according to Embodiment 1, at least one of the first component 2 and the second component 3 may have a surface roughness at a portion corresponding to a third portion of the formed lens 1 that is thicker than the first portion and thinner than the second portion, which is less than the surface roughness of the portion corresponding to the first portion and greater than the surface roughness of the portion corresponding to the second portion. With this configuration, since the surface of the mold component has a surface roughness corresponding to the relative thickness of the formed lens 1, the timing of demolding progress can be controlled more appropriately. As a result, sudden changes in stress during molding can be suppressed, the occurrence of cracks in the glass lens can be suppressed, and a glass lens with suppressed light distribution propagation can be manufactured.

[0042] The surface roughness of at least one of the first component 2 and the second component 3 can be continuously varied. For example, at least one of the first component 2 and the second component 3 can have a surface roughness corresponding to the thickness of the lens 1 after molding. More specifically, at least one of the first component 2 and the second component 3 can have a surface roughness such that the thinner the lens 1 after molding, the greater the surface roughness at the portion corresponding to the portion of the lens 1. According to this configuration, since the surface of the mold component has a surface roughness corresponding to the relative thickness of the lens 1 after molding, the timing of demolding progress can be more appropriately controlled. As a result, sudden changes in stress can be suppressed during molding, the occurrence of cracks in the glass lens can be suppressed, and a glass lens with suppressed light distribution propagation can be manufactured.

[0043] Methods for applying surface roughness to mold 4 may include, for example, laser processing, ion beam processing, polishing, and sandblasting. However, the methods for applying surface roughness to mold 4 are not limited to these, and any method may be used as desired. Furthermore, in addition to transferring surface roughness by molding mold 4, any method for applying surface roughness to lens 1, such as laser processing, ion beam processing, polishing, and sandblasting, may be used as desired.

[0044] The surface roughness of lens 1, including the surface roughness at its thickest and thinnest points, can be set, for example, to an arithmetic mean roughness of 2 nmRa to 12 nmRa. In this case, lens 1 can have a preferred transmittance for use as an optical lens. The difference between the maximum and minimum thickness of lens 1 can be set, for example, to 0.4 mm to 5.0 mm. By setting the difference between the maximum and minimum thickness of lens 1 to 5.0 mm or less, it is possible to adjust the surface roughness of lens 1 to make the transmittance of lens 1 uniform. Furthermore, by setting the difference between the maximum and minimum thickness of lens 1 to 0.4 mm or greater, when lens 1 is used as an optical lens, the effect of a gull-shaped lens (e.g., light bending amount, etc.) can be appropriately applied. [Methods for measuring light distribution]

[0045] Next, a method for measuring the light distribution of lens 1 according to Embodiment 1 will be described. First, light emitted from the light source passes through lens 1 and is projected onto the projection surface. Then, the projected light is measured using, for example, a two-dimensional imaging color luminance meter to obtain the light distribution. An illuminance meter or a luminance meter can be used for the measurement. Alternatively, a lens unit can be formed using the molded lens 1, and the light distribution can be obtained from the imaging results. [Methods for evaluating the surface roughness of molds]

[0046] Next, an evaluation method for assessing the surface roughness of mold 4 according to Example 1 will be described. Figure 3 It is a diagram illustrating the measurement location of the surface roughness of the mold 4 according to Embodiment 1, and a cross-sectional view of an example of the first component 2 of the mold 4 along the optical axis of the lens 1 to be formed. Figure 3 The thickness distribution 310 shown indicates Figure 1 The thickness distribution of the effective region within the thickness distribution 110 shown.

[0047] First, the thickness distribution 310 of the shaped lens 1 along the optical axis is obtained. The method for obtaining the thickness distribution 310 can be any known method, and for example, it can be obtained using a known thickness measuring device. On the thickness distribution 310, such as... Figure 3As shown, there exists a point group including point 311 corresponding to the intersection with the optical axis, effective region endpoint 314, and extreme point 312 with an extreme value. The position in the radial direction corresponding to point 311 is the optical axis position, where point 311 corresponds to the intersection with the optical axis. Furthermore, the position in the radial direction corresponding to extreme point 312 is the extreme position. During forming, the lens 1 contacts point 201 corresponding to the thickest point and point 202 corresponding to the thinnest point on the surface of the first member 2 at the positions in the radial direction corresponding to this point group. Therefore, point 201 corresponding to the thickest point of the lens 1 and point 202 corresponding to the thinnest point of the lens 1 are set as points for evaluating the surface roughness of the first member 2. Furthermore, point 203, freely selected from positions within the effective diameter other than point 201 corresponding to the thickest point and point 202 corresponding to the thinnest point, is set as a point for evaluating the surface roughness of the first member 2. Point 203 corresponds to point 316 on the thickness distribution 310.

[0048] Next, the surface roughness at points 201, 202, and 203 of the first component 2 is measured using, for example, a contact roughness measuring instrument. As a result, the arithmetic mean roughness (Ra) or power spectral density (PSD) at each of the points 201, 202, and 203 of the first component 2 of the mold 4 is evaluated.

[0049] An evaluation method for assessing the surface roughness of the first component 2 has been described. The surface roughness of the second component 3 can be evaluated using a similar method. The evaluation index for surface roughness is not limited to arithmetic surface roughness or power spectral density, and can be any other known evaluation index. Depending on the shape of the sample to be evaluated (such as mold 4), measurement may be difficult due to interference between the sample and the measuring instrument. In such cases, evaluation can be performed by replacing the roughness with a planar sample subjected to similar conditions.

[0050] In the following description, a lens, a mold, and a molding method according to Embodiment 1 of the present disclosure will be described with reference to examples and comparative examples. As examples, Examples 1 to 5 of obtaining a glass lens having a desired arithmetic mean roughness by intentionally applying a desired arithmetic mean roughness to the surface of a mold 4, and Examples 6 to 10 of obtaining a glass lens having a desired PSD by intentionally applying a desired PSD to the surface of a mold 4 will be described. As comparative examples, Comparative Examples 1 to 5 of obtaining a glass lens having a desired arithmetic mean roughness by intentionally applying a desired arithmetic mean roughness to the surface of a mold 4, and Comparative Examples 6 to 10 of obtaining a glass lens having a desired PSD by intentionally applying a desired PSD to the surface of a mold 4 will be described.

[0051] The following will refer to Figures 4A to 4D The surface roughness treatment applied to the mold 4 according to Example 1 is described. Figure 4A and Figure 4B An example of the arithmetic mean roughness at points on the mold surface according to Embodiment 1 is shown, and Figure 4C and Figure 4D An example of a logarithmic PSD at a point on the surface of a mold according to Example 1 is shown.

[0052] In Examples 1 to 5, a surface roughness treatment is applied to mold 4 such that the arithmetic mean roughness 401 at the point on the mold surface that contacts the thinnest point of the lens during molding (e.g., Figure 4A (As shown) The arithmetic mean roughness at the point on the mold surface that contacts the thickest point of the lens during molding is greater than 402 (e.g.) Figure 4B As shown). In Examples 6 to 10, a surface roughness treatment is applied to the mold 4 such that the spatial frequency of the extreme value 403 of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] at the point on the mold surface that contacts the thinnest point of the lens during molding is (as shown). Figure 4C (As shown) The spatial frequency of the extreme value of PSD 404 in the same spatial frequency range above the point on the mold surface that contacts the thickest point of the lens during molding (as shown) Figure 4D (As shown). Note that this disclosure is not limited to the following examples.

[0053] First, Examples 1 to 5 and Comparative Examples 1 to 5 will be presented to describe the application of the desired arithmetic mean roughness as the surface roughness of mold 4. (Example 1)

[0054] In Example 1, a glass lens with concave sides near the center is formed. A pair of molds 4 are prepared by forming such that the thickness of the thickest point of the lens becomes 3.5 mm, the thickness of the thinnest point becomes 1.2 mm, and the thickness of a point freely selected from positions other than the thickest and thinnest points becomes 2.0 mm.

[0055] In Example 1, both the first component 2 and the second component 3 of the mold 4 are subjected to a process for applying surface roughness. Specifically, this process is performed such that the surface roughness of the mold 4 at the point of contact with the thickest point of the formed lens becomes 2.0 nmRa, the surface roughness of the mold 4 at the point of contact with the thinnest point of the lens becomes 7.0 nmRa, and the surface roughness of the mold 4 at the point of contact with a freely chosen point of the lens becomes 3.4 nmRa.

[0056] Molding is performed using mold 4 as follows. Optical glass with a glass transition temperature of 615°C is used as the preform. An infrared heater is used to heat mold 4 and the preform. First, mold 4 is heated to a first temperature (580°C), and then the preform is placed in the mold. Next, mold 4 and the preform are heated to a second temperature (680°C) above the first temperature to soften the preform until its viscosity becomes suitable for pressure molding. Then, mold 4 and the preform are brought into contact by applying a first load (4000 N) to mold the preform into the desired glass lens shape. Finally, when mold 4 reaches a temperature below the second temperature (580°C), the applied load is unloaded. When the load is unloaded, the glass lens, which had been pressurized beforehand, may deform, and the glass lens is released from mold 4.

[0057] In Example 1, a crack-free glass lens was formed under these forming conditions. When the surface roughness of the thickest and thinnest points of the formed lens was measured, it was confirmed that the surface roughness of the thinnest point was greater than that of the thickest point, and it was also confirmed that there was essentially no light distribution. Furthermore, when a lens unit was manufactured using the formed lens and installed in an information terminal, it was confirmed that good imaging performance was obtained. (Example 2)

[0058] In Example 2, a glass lens is formed having a concave shape on one side and a convex shape on the other side near the center. A pair of molds 4 are prepared by molding such that the thickness of the thickest point of the lens becomes 1.0 mm, the thickness of the thinnest point becomes 0.6 mm, and the thickness of points freely selected from positions other than the thickest and thinnest points becomes 0.7 mm.

[0059] In Example 2, both the first component 2 and the second component 3 of the mold 4 are subjected to a process for applying surface roughness. Specifically, this process is performed such that the surface roughness of the mold 4 at the point of contact with the thickest point of the formed lens becomes 3.1 nmRa, the surface roughness of the mold 4 at the point of contact with the thinnest point of the lens becomes 5.6 nmRa, and the surface roughness of the mold 4 at the point of contact with a freely chosen point of the lens becomes 4.8 nmRa.

[0060] The molding process was carried out using mold 4 in the same manner as in Example 1. Similarly, in Example 2, a glass lens without cracks was molded. When the roughness of the thickest and thinnest points of the molded lens was measured, it was confirmed that the roughness of the thinnest point was greater than that of the thickest point, and it was also confirmed that the light intensity distribution was small (narrow). (Example 3)

[0061] In Example 3, a glass lens with bilateral convex shapes near the center is formed. A pair of molds 4 are prepared by forming such that the thickness of the thickest point of the lens becomes 4.6 mm, the thickness of the thinnest point is 0.5 mm, and the thickness of points freely selected from positions other than the thickest and thinnest points becomes 3.0 mm.

[0062] In Example 3, only the first component 2 of the mold 4 is subjected to a surface roughness treatment. Specifically, this treatment is performed such that the surface roughness of the mold 4 at the point of contact with the thickest point of the formed lens becomes 5.7 nmRa, the surface roughness of the mold 4 at the point of contact with the thinnest point of the lens becomes 9.5 nmRa, and the surface roughness of the mold 4 at the point of contact with a freely chosen point of contact with the lens becomes 7.2 nmRa.

[0063] The molding process was carried out using mold 4 in the same manner as in Example 1. Similarly, in Example 3, a crack-free glass lens was molded. When the roughness of the thickest and thinnest points of the molded lens was measured, it was confirmed that the roughness of the thinnest point was greater than that of the thickest point, and it was also confirmed that there was essentially no light distribution. (Example 4)

[0064] In Example 4, a glass lens is formed having a concave shape on one side and a convex shape on the other side near the center. A pair of molds 4 are prepared by molding such that the thickness of the thickest point of the lens becomes 5.3 mm, the thickness of the thinnest point becomes 2.1 mm, and the thickness of points freely selected from positions other than the thickest and thinnest points becomes 3.6 mm.

[0065] In Example 4, only the first component 2 of the mold 4 is subjected to a surface roughness treatment. Specifically, this treatment is performed such that the surface roughness of the mold 4 at the point of contact with the thickest point of the formed lens becomes 2.4 nmRa, the surface roughness of the mold 4 at the point of contact with the thinnest point of the lens becomes 6.9 nmRa, and the surface roughness of the mold 4 at the point of contact with a freely chosen point of contact with the lens becomes 10.6 nmRa.

[0066] The molding process was carried out using mold 4 in the same manner as in Example 1. In Example 4, some cracks were observed. However, the molding was performed to the extent that it did not cause any dimensional problems. Furthermore, when the roughness of the thickest and thinnest points of the molded lens was measured, it was confirmed that the roughness of the thinnest point was greater than that of the thickest point, and it was also confirmed that there was essentially no light distribution. (Example 5)

[0067] In Example 5, a glass lens is formed having a concave shape on one side and a convex shape on the other side near the center. A pair of molds 4 are prepared by molding such that the thickness of the thickest point of the lens becomes 2.3 mm, the thickness of the thinnest point becomes 1.4 mm, and the thickness of points freely selected from positions other than the thickest and thinnest points becomes 1.7 mm.

[0068] In Example 5, only the second component 3 of the mold 4 is subjected to a surface roughness treatment. Specifically, this treatment is performed such that the surface roughness of the mold 4 at the point of contact with the thickest point of the formed lens becomes 3.8 nmRa, the surface roughness of the mold 4 at the point of contact with the thinnest point of the lens becomes 6.5 nmRa, and the surface roughness of the mold 4 at the point of contact with a freely chosen point becomes 1.1 nmRa.

[0069] The molding process was carried out using mold 4 in the same manner as in Example 1. In Example 5, some cracks were observed. However, the molding was carried out to the extent that it did not cause any dimensional problems. Furthermore, when the roughness of the thickest and thinnest points of the molded lens was measured, it was confirmed that the roughness of the thinnest point was greater than that of the thickest point, and it was also confirmed that the light distribution was small. (Comparative Example 1)

[0070] In Comparative Example 1, a glass lens with the same shape as in Example 1 was formed. In Comparative Example 1, both the first component 2 and the second component 3 of the mold 4 were subjected to a process for applying surface roughness. Specifically, this process was performed such that the surface roughness of the mold 4 at the point of contact with the thickest point of the formed lens became 8.0 nmRa, the surface roughness of the mold 4 at the point of contact with the thinnest point of the lens became 4.0 nmRa, and the surface roughness of the mold 4 at the point of contact with a freely selected point of the lens became 3.2 nmRa.

[0071] The molding process was performed using mold 4 in the same manner as in Example 1. Some cracks were also observed in Comparative Example 1. However, the molding was carried out to the extent that it did not cause any dimensional problems. When the roughness of the thickest and thinnest points of the molded lens was measured, it was confirmed that the roughness of the thinnest point was greater than that of the thickest point, but the light distribution was large, which caused dimensional problems. (Comparative Example 2)

[0072] In Comparative Example 2, a glass lens with the same shape as in Example 2 was formed. In Comparative Example 2, both the first component 2 and the second component 3 of the mold 4 were subjected to a process for applying surface roughness. Specifically, this process was performed such that the surface roughness of the mold 4 at the point of contact with the thickest point of the formed lens became 3.1 nmRa, the surface roughness of the mold 4 at the point of contact with the thinnest point of the lens became 1.2 nmRa, and the surface roughness of the mold 4 at the point of contact with a freely selected point of the lens became 1.5 nmRa.

[0073] The molding process was performed using mold 4 in the same manner as in Example 1. In Comparative Example 2, the applied load was finally unloaded when the temperature of mold 4 fell below the second temperature (580°C), but the mold cracked and molding could not be completed. Because molding could not be completed, the light distribution could not be measured. (Comparative Example 3)

[0074] In Comparative Example 3, a glass lens with the same shape as in Example 3 was formed. In Comparative Example 3, only the first component 2 of the mold 4 was subjected to a surface roughness treatment. Specifically, this treatment was performed such that the surface roughness of the mold 4 at the point in contact with the thickest point of the formed lens became 5.7 nmRa, the surface roughness of the mold 4 at the point in contact with the thinnest point of the lens became 2.1 nmRa, and the surface roughness of the mold 4 at the point in contact with a freely chosen point of the lens became 3.3 nmRa.

[0075] Molding was performed using mold 4 in the same manner as in Example 1. In Comparative Example 3, the applied load was finally unloaded when the temperature of mold 4 fell below the second temperature (580°C), but cracking occurred and molding could not be completed. Because molding could not be completed, the light distribution could not be measured. (Comparative Example 4)

[0076] In Comparative Example 4, a glass lens having the same shape as in Example 4 was formed. In Comparative Example 4, only the first component 2 of the mold 4 was subjected to a process for applying surface roughness. Specifically, this process was performed such that the surface roughness of the mold 4 at the point in contact with the thickest point of the formed lens became 12.4 nmRa, the surface roughness of the mold 4 at the point in contact with the thinnest point of the lens became 6.9 nmRa, and the surface roughness of the mold 4 at the point in contact with a freely chosen point became 10.6 nmRa.

[0077] The molding process was performed using mold 4 in the same manner as in Example 1. In Comparative Example 4, the applied load was finally unloaded when the temperature of mold 4 fell below the second temperature (580°C), but cracking occurred and molding could not be completed. Because molding could not be completed, the light distribution could not be achieved. (Comparative Example 5)

[0078] In Comparative Example 5, a glass lens with the same shape as in Example 5 was formed. In Comparative Example 5, only the second component 3 of the mold 4 was subjected to a surface roughness treatment. Specifically, this treatment was performed such that the surface roughness of the mold 4 at the point in contact with the thickest point of the formed lens became 7.8 nmRa, the surface roughness of the mold 4 at the point in contact with the thinnest point of the lens became 6.5 nmRa, and the surface roughness of the mold 4 at the point in contact with a freely chosen point of the lens became 1.1 nmRa.

[0079] Molding was performed using mold 4 in the same manner as in Example 1. In Comparative Example 5, the applied load was finally unloaded when the temperature of mold 4 fell below the second temperature (580°C), but cracking occurred and molding could not be completed. Because molding could not be completed, the light distribution could not be measured.

[0080] Table 1 below shows the shape of the glass lenses according to Examples 1 to 5 and Comparative Examples 1 to 5, the surface roughness measurement results of mold 4, the light distribution of the lenses, and the results of breakage during molding (degree of breakage). As an evaluation criterion for the light distribution of the lenses, C is defined as a case where the light distribution cannot be confirmed, B is defined as a case where the light distribution can be confirmed to a certain extent but there are no dimensional problems, and A is defined as a case where the light distribution has dimensional problems. Furthermore, as an evaluation criterion for cracks during molding, C is defined as a case where cracks cannot be confirmed, B is defined as a case where some cracks can be confirmed but there are no dimensional problems, and A is defined as a case where cracks can be confirmed to the extent that dimensional problems exist. [Table 1]

[0081] In Examples 1 to 5, as shown in Table 1, the expansion of the light distribution can be suppressed. Therefore, it has been found that the light distribution can be suppressed in a configuration where at least one surface of the lens 1 has a surface roughness greater than that of other portions in the relatively thinner portion of the lens 1 after forming.

[0082] Furthermore, in Examples 1 to 5, as shown in Table 1, the occurrence of cracks can be suppressed. Therefore, it has been found that the occurrence of cracks can be suppressed in a configuration where at least one of the first member 2 and the second member 3 has a surface roughness greater than that of other portions at a portion corresponding to a relatively thin portion of the formed lens 1.

[0083] Furthermore, in Examples 1 to 3, the occurrence of cracks can be further suppressed. For this reason, it has been found that in the configuration where at least one of the portions corresponding to the third portion of the formed lens 1, which is thicker than the first portion and thinner than the second portion, has a surface roughness that is less than that of the portion corresponding to the first portion but greater than that of the portion corresponding to the second portion, the occurrence of cracks can be further suppressed.

[0084] Next, Examples 6 to 10 and Comparative Examples 6 to 10, in which the desired PSD was applied as the surface roughness of mold 4, will be described. (Example 6)

[0085] In Example 6, a glass lens with concave sides near the center is formed. A pair of molds 4 are prepared by forming such that the thickness of the thickest point of the lens becomes 3.5 mm, the thickness of the thinnest point becomes 1.2 mm, and the thickness of a point freely selected from positions other than the thickest and thinnest points becomes 2.0 mm.

[0086] In Example 6, both the first component 2 and the second component 3 of the mold 4 are subjected to a process for applying surface roughness. Specifically, the process is performed such that the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thickest point of the formed lens becomes 7584 [1 / mm], the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thinnest point of the lens becomes 9505 [1 / mm], and the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with a freely selected point of contact with the lens becomes 8546 [1 / mm].

[0087] The molding process was performed using mold 4 in the same manner as in Example 1. In Example 6, a glass lens without cracks was molded. Furthermore, when the spatial frequencies of the extreme values ​​of PSD (6000 [1 / mm] to 10000 [1 / mm]) on the surface of the molded lens were measured at the thickest and thinnest points, it was confirmed that the spatial frequency of the extreme value of PSD at the thinnest point was higher than that at the thickest point, and it was also confirmed that there was no light distribution. In addition, when a lens unit was manufactured using the molded lens and installed on an information terminal, good imaging performance was confirmed. (Example 7)

[0088] In Example 7, a glass lens is formed having a concave shape on one side and a convex shape on the other side near the center. A pair of molds 4 are prepared by molding such that the thickness of the thickest point of the lens becomes 1.0 mm, the thickness of the thinnest point becomes 0.6 mm, and the thickness of points freely selected from positions other than the thickest and thinnest points becomes 0.7 mm.

[0089] In Example 7, both the first component 2 and the second component 3 of the mold 4 are subjected to a process for applying surface roughness. Specifically, the process is performed such that the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thickest point of the formed lens becomes 7986 [1 / mm], the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thinnest point of the lens becomes 8765 [1 / mm], and the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with a freely selected point of contact with the lens becomes 8454 [1 / mm].

[0090] The molding process was performed using mold 4 in the same manner as in Example 1. Similarly, in Example 7, a glass lens without cracks was molded. Furthermore, when the spatial frequencies of the extreme values ​​of the PSD (Photometric Spectrum Dispersion) on the surface of the molded lens were measured at the thickest and thinnest points, it was confirmed that the spatial frequency of the extreme value of the PSD at the thinnest point was higher than that at the thickest point, and that the light distribution was also smaller. (Example 8)

[0091] In Example 8, a glass lens with bilaterally convex shapes near the center is formed. A pair of molds 4 are prepared by forming such that the thickness of the thickest point of the lens becomes 4.6 mm, the thickness of the thinnest point becomes 0.5 mm, and the thickness of a point freely selected from positions other than the thickest and thinnest points becomes 3.0 mm.

[0092] In Example 8, only the first component 2 of the mold 4 is subjected to a surface roughness treatment. Specifically, the treatment is performed such that the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thickest point of the formed lens becomes 6954 [1 / mm], the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thinnest point of the lens becomes 7561 [1 / mm], and the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with a freely selected point of the lens becomes 7254 [1 / mm].

[0093] The molding process was performed using mold 4 in the same manner as in Example 1. Similarly, in Example 8, a glass lens without cracks was molded. Furthermore, when the spatial frequencies of the extreme values ​​of PSD on the surface of the molded lens in the range of 6000 [1 / mm] to 10000 [1 / mm] were measured at the thickest and thinnest points, it was confirmed that the spatial frequency of the extreme value of PSD at the thinnest point was higher than that at the thickest point, and it was also confirmed that there was no light distribution. (Example 9)

[0094] In Example 9, a glass lens is formed having a concave shape on one side and a convex shape on the other side near the center. A pair of molds 4 are prepared by molding such that the thickness of the thickest point of the lens becomes 5.3 mm, the thickness of the thinnest point becomes 2.1 mm, and the thickness of points freely selected from positions other than the thickest and thinnest points becomes 3.6 mm.

[0095] In Example 9, only the first component 2 of the mold 4 is subjected to a surface roughness treatment. Specifically, the treatment is performed such that the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thickest point of the formed lens becomes 6231 [1 / mm], the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thinnest point of the lens becomes 6845 [1 / mm], and the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with a freely selected point of the lens is 6980 [1 / mm].

[0096] The molding process was carried out using mold 4 in the same manner as in Example 1. In Example 9, some cracks were observed, but the molding was carried out to the extent that it did not cause any dimensional problems. In addition, when the spatial frequencies of the extreme values ​​of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the surface of the molded lens were measured at the thickest and thinnest points, it was confirmed that the spatial frequency of the extreme value of PSD at the thinnest point was higher than that at the thickest point, and it was also confirmed that there was no light distribution. (Example 10)

[0097] In Example 10, a glass lens is formed having a concave shape on one side and a convex shape on the other side near the center. A pair of molds 4 are prepared by molding such that the thickness of the thickest point of the lens becomes 2.3 mm, the thickness of the thinnest point becomes 1.4 mm, and the thickness of points freely selected from positions other than the thickest and thinnest points becomes 1.7 mm.

[0098] In Example 10, only the second component 3 of the mold 4 is subjected to a surface roughness treatment. Specifically, the treatment is performed such that the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thickest point of the formed lens becomes 8995 [1 / mm], the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with the thinnest point of the lens becomes 9175 [1 / mm], and the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point of contact with a freely selected point of contact with the lens becomes 8357 [1 / mm].

[0099] The molding process was carried out using the same method as in Example 1, with mold 4. Also in Example 10, some cracks were identified, but molding was performed to the extent that it did not cause dimensional issues. Furthermore, when the spatial frequencies of the extreme values ​​of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the surface of the molded lens were measured at the thickest and thinnest points, it was confirmed that the spatial frequency of the extreme value of PSD at the thinnest point was higher than that at the thickest point, and it was also confirmed that the light intensity distribution was smaller. (Comparative Example 6)

[0100] In Comparative Example 6, a glass lens with the same shape as in Example 6 was formed. In Comparative Example 6, both the first component 2 and the second component 3 of the mold 4 were subjected to a process for applying surface roughness. Specifically, the process was performed such that the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point in contact with the thickest point of the formed lens became 9910 [1 / mm], the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point in contact with the thinnest point of the lens became 7500 [1 / mm], and the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface at the point in contact with a freely selected point of the lens became 6854 [1 / mm].

[0101] The molding process was carried out using mold 4 in the same manner as in Example 1. Similarly, in Comparative Example 6, some cracks were identified, but molding was performed to the extent that it did not cause any dimensional problems. Furthermore, when the spatial frequencies of the extreme values ​​of the PSD on the surface of the molded lens were measured at the thickest and thinnest points, it was confirmed that the spatial frequency of the extreme value of the PSD at the thinnest point was higher than that at the thickest point, but the light intensity distribution was larger, which caused dimensional problems. (Comparative Example 7)

[0102] In Comparative Example 7, a glass lens with the same shape as in Example 7 was formed. In Comparative Example 7, both the first component 2 and the second component 3 of the mold 4 were subjected to a process for applying surface roughness. Specifically, the process was performed such that the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts the thickest point of the formed lens became 7423 [1 / mm], the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts the thinnest point of the lens became 6156 [1 / mm], and the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts a freely selected point of the lens became 6985 [1 / mm].

[0103] The molding process was performed using mold 4 in the same manner as in Example 1. In Comparative Example 7, the applied load was finally unloaded when the temperature of mold 4 fell below the second temperature (580°C), but the mold cracked and molding could not be completed. Because molding could not be completed, the light intensity distribution could not be measured. (Comparative Example 8)

[0104] In Comparative Example 8, a glass lens with the same shape as in Example 8 was formed. In Comparative Example 8, only the first component 2 of the mold 4 was subjected to a process for applying surface roughness. Specifically, the process was performed such that the spatial frequency of the extreme value of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts the thickest point of the formed lens became 6465 [1 / mm], the spatial frequency of the extreme value of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts the thinnest point of the lens became 6065 [1 / mm], and the spatial frequency of the extreme value of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts a freely selected point of the lens became 6254 [1 / mm].

[0105] Molding was performed using mold 4 in the same manner as in Example 1. In Comparative Example 8, the applied load was finally unloaded when the temperature of mold 4 fell below the second temperature (580°C), but cracking occurred and molding could not be completed. Because molding could not be completed, the light distribution could not be measured. (Comparative Example 9)

[0106] In Comparative Example 9, a glass lens with the same shape as in Example 9 was formed. In Comparative Example 9, only the first component 2 of the mold 4 was subjected to a process for applying surface roughness. Specifically, the process was performed such that the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts the thickest point of the formed lens became 8465 [1 / mm], the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts the thinnest point of the lens became 7454 [1 / mm], and the spatial frequency of the extreme value of the PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts a freely selected point of the lens became 8045 [1 / mm].

[0107] Molding was performed using mold 4 in the same manner as in Example 1. In Comparative Example 9, the applied load was finally unloaded when the temperature of mold 4 fell below the second temperature (580°C), but cracking occurred and molding could not be completed. Because molding could not be completed, the light distribution could not be measured. (Comparative Example 10)

[0108] In Comparative Example 10, a glass lens having the same shape as in Example 10 was formed. In Comparative Example 10, only the second component 3 of the mold 4 was subjected to a process for applying surface roughness. Specifically, the process was performed such that the spatial frequency of the extreme value of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts the thickest point of the formed lens became 6946 [1 / mm], the spatial frequency of the extreme value of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts the thinnest point of the lens became 6656 [1 / mm], and the spatial frequency of the extreme value of PSD in the spatial frequency range of 6000 [1 / mm] to 10000 [1 / mm] on the mold surface that contacts a freely selected point of the lens became 6257 [1 / mm].

[0109] Molding was performed using mold 4 in the same manner as in Example 1. In Comparative Example 10, the applied load was finally unloaded when the temperature of mold 4 fell below the second temperature (580°C), but cracking occurred and molding could not be completed. Because molding could not be completed, the light distribution could not be measured.

[0110] Table 2 below shows the shape of the glass lenses in Examples 6 to 10 and Comparative Examples 6 to 10, the surface roughness measurement results of mold 4, the light distribution of the lenses, and the results of breakage during molding (degree of breakage). As an evaluation criterion for the light distribution of the lenses, C is defined as a case where the light distribution cannot be confirmed, B is defined as a case where the light distribution can be confirmed to a certain extent but there are no dimensional problems, and A is defined as a case where the light distribution has dimensional problems. Furthermore, as an evaluation criterion for cracks during molding, C is defined as a case where cracks cannot be confirmed, B is defined as a case where some cracks can be confirmed but there are no dimensional problems, and A is defined as a case where cracks can be confirmed to the extent that dimensional problems exist. [Table 2]

[0111] In Examples 6 to 10, as shown in Table 2, light distribution can be suppressed. Therefore, it has been found that in a configuration where at least one surface of lens 1 has a surface roughness greater than that of other portions of the relatively thinner portion of lens 1 after forming, light distribution expansion can be suppressed.

[0112] Furthermore, in Examples 6 to 10, as shown in Table 2, the occurrence of cracks can be suppressed. Therefore, it has been found that the occurrence of cracks can be suppressed in a configuration where at least one of the first member 2 and the second member 3 has a surface roughness greater than that of other portions at a portion corresponding to a relatively thin portion of the formed lens 1.

[0113] Furthermore, in Examples 6 to 8, the occurrence of cracks can be further suppressed. For this reason, it has been found that in a configuration where at least one of the first member 2 and the second member 3 has a surface roughness at the portion corresponding to the third portion of the formed lens 1 that is thicker than the first portion and thinner than the second portion, the occurrence of cracks can be further suppressed. (Example 2)

[0114] Next, we will refer to Figure 5 The lens unit according to Embodiment 2 of this disclosure is described. Figure 5 An example of a lens unit according to Embodiment 2 is shown. The lens unit 500 according to Embodiment 2 includes a plurality of lenses 501, 502, 503 and a lens barrel 504. The lens barrel 504 holds the plurality of lenses 501, 502, 503. Here, the plurality of lenses 501, 502, 503 are configured using the lenses described in Embodiment 1.

[0115] With this configuration, lens units using high-precision glass lenses can be produced stably because the lens unit is constructed using glass lenses with a small light distribution and designed to prevent breakage during molding.

[0116] The lens unit may include at least one lens as described in Embodiment 1, and the plurality of lenses included in the lens unit may include other lenses. The number of the plurality of lenses is not limited to three, and the lens unit may include two or more lenses. (Example 3)

[0117] Next, we will refer to Figure 6 The information terminal is described according to Embodiment 3 of this disclosure. Figure 6 An example of an information terminal according to this embodiment is shown. The information terminal according to Embodiment 3 can be any known information terminal such as a mobile phone, smartphone, laptop PC (personal computer), or tablet terminal. The information terminal 600 according to this embodiment includes a lens 601 and an image sensor 602. The lens 601 is configured using the lens described in Embodiment 1. The image sensor 602 can capture images via the lens 601.

[0118] With this configuration, since the information terminal is configured using lenses with a small light distribution and designed to prevent breakage during molding, it is possible to stably produce information terminals that use high-precision lenses and have good imaging performance. Note that the information terminal 600 may include two or more of the lenses described in Embodiment 1. Furthermore, the information terminal 600 may include the lens unit described in Embodiment 2. (Example 4)

[0119] Next, we will refer to Figure 7 A camera device according to Embodiment 4 of this disclosure is described. Figure 7 An example of a camera device according to Embodiment 4 is shown. The camera device according to Embodiment 4 can be any known camera device such as a digital camera or an analog camera. The camera device 700 according to Embodiment 4 includes a lens 701 and an image sensor 702. The lens 701 is configured using the lens described in Embodiment 1. The image sensor 702 can capture images via the lens 701.

[0120] With this configuration, because the image sensor is configured using lenses with a small light distribution and to prevent breakage during molding, imaging devices using high-precision lenses and possessing good imaging performance can be produced stably. The imaging device may include two or more of the lenses described in Embodiment 1. Imaging device 700 may include the lens unit described in Embodiment 2.

[0121] In embodiments 1 to 4, the lens according to this disclosure is described as a glass lens. However, the material of the lens is not limited to glass. The lens according to this disclosure can be molded from, for example, plastic or any resin. A mold can be used to injection mold the plastic lens.

[0122] According to the first aspect of this disclosure, the optical properties of aspherical lenses can be improved. Furthermore, according to the second aspect of this disclosure, the occurrence of cracks in aspherical lenses during the forming process can be suppressed.

[0123] While this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A lens, comprising a first optically effective surface and a second optically effective surface intersecting the optical axis. in, At least one of the first and second optically effective surfaces has an inflection point between its intersection with the optical axis and the end of the effective region; The thickness distribution between the first optically effective surface and the second optically effective surface has extreme values ​​in the direction parallel to the optical axis, and in the direction perpendicular to the optical axis, it is located away from the optical axis. At least one of the first and second optically effective surfaces has a surface roughness at a first portion of the lens that is greater than the surface roughness of the second portion, and the second portion is thicker than the first portion; as well as The difference between the surface roughness of the first part and the surface roughness of the second part is equal to or greater than 1.0 nmRa according to the arithmetic mean roughness.

2. The lens according to claim 1, wherein, The difference between the surface roughness of the first part and the surface roughness of the second part is equal to or less than 10 nmRa according to the arithmetic mean roughness.

3. The lens according to claim 1, wherein, At least one of the first and second optically effective surfaces of the lens has a surface roughness at a third portion that is thicker than the first portion and thinner than the second portion, which is less than the surface roughness of the first portion and greater than the surface roughness of the second portion.

4. The lens according to claim 1, wherein, At least one of the first and second optically effective surfaces of the lens has a surface roughness greater than that of the point with the largest thickness in the point group in the thickness distribution of the lens at the point with the smallest thickness, wherein the point group includes a point corresponding to the intersection with the optical axis, a point corresponding to the end of the effective region of the lens, and a point having the extreme value.

5. The lens according to claim 4, wherein, At least one of the first and second optically effective surfaces of the lens has a surface roughness at a point in the point group that is farthest from the point with the smallest thickness and the point with the largest thickness, which is less than the surface roughness of the point with the smallest thickness and greater than the surface roughness of the point with the largest thickness.

6. The lens according to claim 1, wherein, The surface roughness of at least one of the first and second optically effective surfaces of the lens changes in stages or continuously.

7. The lens according to claim 1, wherein, The surface roughness of at least one of the first and second optically effective surfaces of the lens is applied based on the thickness of the lens.

8. The lens according to claim 7, wherein, At least one of the first and second optically effective surfaces of the lens has a surface roughness such that the thinner a portion of the lens, the greater the surface roughness of that portion of the lens.

9. The lens according to claim 1, wherein, The first and second optically effective surfaces of the lens have at least one surface roughness applied by at least one of laser processing, polishing, ion beam processing, and sandblasting.

10. The lens according to claim 1, wherein, The surface roughness of the first portion and the second portion of at least one of the first optically effective surface and the second optically effective surface of the lens is between 2 nm Ra and 12 nm Ra, based on an arithmetic mean roughness.

11. The lens according to claim 1, wherein, The surface roughness of the first portion and the second portion of at least one of the first and second optically effective surfaces of the lens has a spatial frequency higher than the extreme value of the power spectral density of the second portion in a spatial frequency range of 6000 to 10000, where the unit of the spatial frequency is 1 / mm.

12. The lens according to claim 1, wherein, The difference between the maximum and minimum thickness of the lens is between 0.4 mm and 5.0 mm.

13. A mold, comprising: A pair of first and second components are used for press-forming a lens having a first optically effective surface and a second optically effective surface intersecting the optical axis, wherein at least one of the first and second optically effective surfaces has an inflection point between the intersection with the optical axis and the end of the effective region, and wherein the thickness distribution between the first and second optically effective surfaces in a direction parallel to the optical axis has an extreme value at a position away from the optical axis in a direction perpendicular to the optical axis. Wherein, at least one of the first component and the second component has a surface roughness at a first corresponding portion corresponding to the first portion of the lens that is greater than the surface roughness of a second corresponding portion corresponding to the second portion of the lens, and the thickness of the second portion of the lens is greater than that of the first portion.

14. The mold according to claim 13, wherein, The difference between the surface roughness of the first corresponding part and the surface roughness of the second corresponding part is equal to or greater than 1.0 nmRa and equal to or less than 10 nmRa according to the arithmetic mean roughness.

15. The mold according to claim 13, wherein, The surface roughness of the first corresponding portion and the second corresponding portion is between 2 nmRa and 12 nmRa according to the arithmetic mean roughness.

16. The mold according to claim 13, wherein, The surface roughness of the first corresponding portion and the second corresponding portion of at least one of the first component and the second component has a spatial frequency higher than the extreme value of the power spectral density of the second portion in a spatial frequency range of 6000 to 10000, where the unit of the spatial frequency is 1 / mm.

17. A lens unit, comprising: The lens according to any one of claims 1 to 12; as well as A lens barrel that holds a plurality of lenses, including the lens.

18. An information terminal, comprising: The lens according to any one of claims 1 to 12; as well as An image sensor is configured to capture images via the lens.

19. A camera device, comprising: The lens according to any one of claims 1 to 12; as well as An image sensor is configured to capture images via the lens.

20. A forming method for press-forming a lens, the lens having a first optically effective surface and a second optically effective surface intersecting an optical axis, the forming method comprising: The lens is press-formed using a mold, wherein at least one of the first and second optically effective surfaces has an inflection point between its intersection with the optical axis and the end of the effective region; wherein the thickness distribution between the first and second optically effective surfaces in a direction parallel to the optical axis has an extreme value at a position away from the optical axis in a direction perpendicular to the optical axis; and wherein at least one of the first and second optically effective surfaces has a surface roughness at a first portion of the lens that is greater than the surface roughness of a second portion, and the second portion is thicker than the first portion. Wherein, the difference between the surface roughness of the first part and the surface roughness of the second part is equal to or greater than 1.0 nmRa according to the arithmetic mean roughness.

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