Electrochromic element, lens for eyeglasses, eyeglasses, and method for manufacturing an electrochromic element

Abstract

The purpose of the present invention is to provide an electrochromic element, an eyeglass lens, eyeglasses, and a method for producing an electrochromic element which make it possible to reduce apparent waviness. The present invention provides an electrochromic element (10) in which a lens base material (1) and an electrochromic film (2) are laminated, said electrochromic element being characterized in that the absolute value of the difference between the maximum value and minimum value of transmission diopter in the entire range of a 40 mm angle in the surface center is within 0.30D.

Description

Technical Field

[0001] The present invention relates to an electrochromic element capable of reversibly controlling electrochromism by electricity, a lens for glasses, glasses, and a method for manufacturing an electrochromic element.

Background Art

[0002] An electrochromic element that utilizes the electrochromism phenomenon of reversibly causing a redox reaction and reversibly changing color by applying a voltage is used, for example, as a lens for glasses.

[0003] In the process of manufacturing an electrochromic element, for example, an electrochromic film is preformed into a curved shape, and then the electrochromic film is placed in a mold and the lens substrate is injection-molded. The completed electrochromic element has a curved shape in which an electrochromic film is laminated on the surface of the lens substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when manufacturing an electrochromic element, unevenness occurs on the surface of the electrochromic element through a heating process or a process of attaching an electrochromic film to a lens substrate. The unevenness appears as shading on the surface when there is uneven refractive power or when an electric current is passed through the electrochromic element to cause coloring.

[0006] However, conventional methods did not control the undulation, which often resulted in uneven power distribution. For example, when electrochromic elements were applied to eyeglass lenses, there was a problem of significant power inconsistency.

[0007] The present invention aims to solve the above problems and to provide an electrochromic element, a lens for eyeglasses, eyeglasses, and a method for manufacturing an electrochromic element that can reduce apparent waviness. [Means for solving the problem]

[0010] An electrochromic element in one aspect of the present invention is an electrochromic element comprising a lens substrate and an electrochromic film laminated together, The electrochromic film The side opposite to the side facing the lens substrate The surface has undulations, and the electrochromic of the lens substrate The side facing the film is The opposite back surface is characterized by being undulating, following the shape of the aforementioned surface.

[0011] In one aspect of the present invention, it is preferable that the back surface of the lens substrate opposite to the side on which the electrochromic film is arranged is polished to form a wavy surface that conforms to the shape of the front surface. Furthermore, in one aspect of the present invention, it is preferable that the electrochromic film is arranged on the convex surface of the lens substrate, and that the concave surface opposite to the convex surface is polished.

[0012] An eyeglass lens in one aspect of the present invention is characterized by using the electrochromic element described above. An eyeglass in one aspect of the present invention is characterized by using a plurality of the eyeglass lenses described above.

[0013] One aspect of the present invention is an electrochromic element comprising a lens substrate and an electrochromic film laminated together, wherein the electrochromic film The side opposite to the side facing the lens substrate The surface has a wavy texture. The electrochromic of the lens substrate The side facing the film is The opposite back surface is characterized by being undulating, following the shape of the aforementioned surface.

[0014] In one aspect of the present invention, it is preferable to measure the surface frequency distribution using reflectance, measure the polishing shape on the back surface based on the reflectance distribution, and polish the back surface in accordance with the polishing shape.

[0015] In one aspect of the present invention, it is preferable to polish the surface so that the absolute value of the difference between the maximum and minimum values ​​of the transmittance within a 40 mm square area in the center of the surface is within 0.30 D.

[0016] Furthermore, in one aspect of the present invention, it is preferable to have the steps of forming the electrochromic element, placing the electrochromic element in a mold and injection molding the lens substrate, measuring the surface frequency distribution of the electrochromic element, and polishing the back surface based on the measurement results of the surface frequency distribution. [Effects of the Invention]

[0017] According to the electrochromic element and its manufacturing method of the present invention, by adjusting the absolute value of the difference between the maximum and minimum values ​​of the transmittance to a predetermined range, the apparent waviness can be reduced and the uniformity of the frequency distribution can be improved. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic cross-sectional view of the electrochromic element in this embodiment. [Figure 2A] This is an explanatory diagram showing the manufacturing process of the electrochromic element in this embodiment. [Figure 2B] This is an explanatory diagram showing the manufacturing process of the electrochromic element in this embodiment. [Figure 2C] This is an explanatory diagram showing the manufacturing process of the electrochromic element in this embodiment. [Figure 2D] It is an explanatory diagram showing the manufacturing process of the electrochromic element in this embodiment. [Figure 2E] It is an explanatory diagram showing the manufacturing process of the electrochromic element in this embodiment. [Figure 3] It is a perspective view of glasses using electrochromic technology. [Figure 4A] It conceptually shows the undulations on the surfaces of a pair of spectacle lenses and shows a comparative example. [Figure 4B] It conceptually shows the undulations on the surfaces of a pair of spectacle lenses and shows an example. [Figure 5A] It is a conceptual diagram showing the surface power distribution. [Figure 5B] It is a conceptual diagram of a spectacle lens showing the transmission power distribution after back grinding based on the surface power distribution (reflection power distribution) shown in FIG. 5A.

Mode for Carrying Out the Invention

[0019] Hereinafter, the mode for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail.

[0020] <The electrochromic element 10 in this embodiment> FIG. 1 is a cross-sectional schematic view of the electrochromic element 10 in this embodiment. The electrochromic element 10 includes a lens substrate 1 and an electrochromic film 2 laminated on the surface of the lens substrate 1.

[0021] [Lens substrate 1] The lens substrate 1 is required to be transparent and have a high transmittance. The lens substrate 1 is not limited to a material, but for example, it is a moldable resin substrate such as polycarbonate resin, acrylic resin, epoxy resin, phenolic resin, or a glass substrate. Among these, it is preferable that the lens substrate 1 is formed of polycarbonate resin from the viewpoints of moldability and manufacturing cost.

[0022] [Electrochromic Film 2] The electrochromic film 2 comprises a pair of first substrates 3 and second substrates 4, a pair of first electrode layers 5 and second electrode layers 6 provided on the inner surfaces of the first substrate 3 and second substrate 4, and an electrochromic layer 7 provided between the first electrode layer 5 and the second electrode layer 6. The electrochromic layer 7 is composed of a reduction layer 7a located on the first electrode layer 5 side, an oxide layer 7b located on the second electrode layer 6 side, and an electrolyte layer 7c provided between the reduction layer 7a and the oxide layer 7b. Thus, the electrochromic film 2 is laminated in the order of second substrate 4 / second electrode layer 6 / oxide layer 7b / electrolyte layer 7c / reduction layer 7a / first electrode layer 5 / first substrate 3 from bottom to top in Figure 1. Reference numeral 16 indicates a sealing layer, and reference numeral 17 indicates a metal terminal portion.

[0023] The substrates 3 and 4 constituting the electrochromic film 2 are in the form of a film or sheet and can be formed from the same resin material as the lens substrate 1. Like the lens substrate 1, the substrates 3 and 4 are required to be transparent and have high transmittance. It is preferable that the substrates 3 and 4 be formed from polycarbonate resin, similar to the lens substrate 1.

[0024] The required properties for the electrode layers 5 and 6 constituting the electrochromic film 2 include transparency, high transmittance, and excellent conductivity. To satisfy these properties, the electrode layers 5 and 6 are transparent electrode layers, and in particular, ITO (indium tin oxide) is preferably used. Existing materials can be used for the reducing layer 7a, the oxidizing layer 7b, and the electrolyte layer 7c that constitute the electrochromic layer 7.

[0025] The reducing layer 7a is a layer that develops color in response to the reduction reaction. Existing reduced electrochromic compounds can be used in the reducing layer 7a. These are not limited to organic or inorganic compounds, but examples include azobenzene, anthraquinone, diarylethene, dihydroprene, dipyridine, styryl, styrylspiropyran, spirooxazine, spirothiopyran, thioindigo, tetrathiafulvalene, terephthalic acid, triphenylmethane, triphenylamine, naphthopyran, viologen, pyrazoline, phenazine, phenylenediamine, phenoxazine, phenothiazine, phthalocyanine, fluorane, fulgide, benzopyran, metallocene, tungsten oxide, molybdenum oxide, iridium oxide, and titanium oxide.

[0026] The oxide layer 7b is a layer that develops color in response to the oxidation reaction. Existing oxidative electrochromic compounds can be used for the oxide layer 7b. While not limited to organic or inorganic compounds, examples include compositions containing radical polymerizable compounds with triarylamines, Prussian blue-type complexes, nickel oxide, iridium oxide, and the like.

[0027] The electrolyte layer 7c preferably possesses electronic insulation and ionic conductivity, and is also transparent. The electrolyte layer 7c may be a solid electrolyte, a gel, or a liquid. A gel is preferable to maintain high ionic conductivity. Although not limited, existing electrolyte materials such as alkali metal salts, alkaline earth metal salts, inorganic ionic salts, quaternary ammonium salts, and acids can be used.

[0028] Although not shown in Figure 1, functional layers such as a hard coat layer or an anti-reflective layer can be provided on the surface of the electrochromic film 2.

[0029] <Method for manufacturing an electrochromic element in this embodiment> Figure 2 is an explanatory diagram showing the method for manufacturing an electrochromic element in this embodiment.

[0030] Figure 2A shows an electrochromic film 2 having a pair of substrates 3 and 4, electrode layers 5 and 6 arranged inside each substrate 3 and 4, and an electrochromic layer 7 sandwiched between each electrode layer 5 and 6. Note that the laminated structure of the electrochromic film 2 is not limited to that shown in Figure 2A, and other laminated structures are also possible.

[0031] Next, as shown in Figure 2B, the electrochromic film 2 is preformed into a curved shape. At this time, the electrochromic film 2 is heated. The heating temperature is not limited, but for example, it is about 100°C.

[0032] When applying the electrochromic element of this embodiment to an eyeglass lens, since the eyeglass lens has a three-dimensional curved surface, it is preferable to preform the electrochromic film 2 into a three-dimensional curved surface before molding the lens substrate 1.

[0033] Next, in Figure 2C, the preformed electrochromic film 2 is set inside a mold 20 consisting of a first mold 21 and a second mold 22, and the lens substrate 1 is injection molded using an injection molding machine 23. Heat is applied during injection molding. The heating temperature is not limited, but for example, it is about 120°C. In Figure 2C, the internal space of the mold 20 is shown as rectangular, but the inner surface in contact with the electrochromic film 2 and the inner surface on the injection port side are curved.

[0034] Next, as shown in Figure 2D, the electrochromic element 10, in which the lens substrate 1 and the electrochromic film 2 are laminated, is removed from the mold 20, and as shown in Figure 2E, the electrochromic element 10 is cut into the shape of an eyeglass lens to obtain an eyeglass lens 30.

[0035] <Conventional challenges in electrochromic devices and an overview of this embodiment> Electrochromic devices are devices that utilize the electrochromic phenomenon, in which a reversible oxidation-reduction reaction occurs when a voltage is applied to both electrodes, causing a reversible change in color.

[0036] For example, the eyeglasses 32 shown in Figure 3 incorporate electrochromic elements using electrochromic technology as a pair of eyeglass lenses 30 into the frame 31, allowing them to function as sunglasses in bright light and as clear lenses in dark light. They can be adjusted to the optimal brightness via a switch or automatically.

[0037] As shown in Figure 1, the electrochromic element 10 has a laminated structure in which an electrochromic film 2 having an electrode layer and an electrochromic layer is laminated on the surface of a lens substrate 1.

[0038] Incidentally, when an electrochromic element was applied to eyeglasses 32 as an eyeglass lens 30, inconsistencies in prescription occurred. It was found that the degree of inconsistency in prescription varied depending on the size of the undulation on the lens surface.

[0039] The undulation occurs due to stress applied during the manufacturing process of the electrochromic element 10, such as the heating process and the process of bonding the electrochromic film 2 to the lens substrate 1. "Undulation" refers to a wave-like shape in which convex and concave portions are repeated.

[0040] Figures 4A and 4B are conceptual diagrams showing the shapes of the front surface 10a and back surface 10b of the electrochromic element 10. Figure 4A shows a comparative example, and Figure 4B shows an embodiment. Note that the undulations are exaggerated in Figures 4A and 4B.

[0041] As shown in the comparative example in Figure 4A, a undulation A occurs on the surface 10a. Since the dashed line represents the ideal value, the actual undulation A deviates from the ideal value. In the comparative example in Figure 4A, the back surface 10b is polished to be nearly flat. That is, the shape of the back surface 10b can be brought closer to the ideal value of the dashed line in Figure 4A. However, as in Figure 4A, when the surface 10a is undulating and the back surface 10b is nearly flat, in other words, when the surface 10a deviates from the ideal value and the back surface 10b is close to the ideal value, frequency unevenness occurs. "Frequency unevenness" refers to the variation in transmittance. Note that in Figure 4A, the "ideal value" is set to flat, but when the surface and back surface are curved, the shape that follows the curved surface is set to the ideal value.

[0042] In light of the conventional problems described above, the inventors have diligently conducted research and have succeeded in reducing the absolute value of the difference between the maximum and minimum values ​​of the transmittance within a predetermined range, thereby seemingly reducing undulation and suppressing unevenness in transmittance.

[0043] Figure 4B shows an example of reducing apparent waviness. Specifically, as shown in the embodiment of Figure 4B, while the surface 10a of the electrochromic element 10 exhibits waviness A that deviates from the ideal value, similar to the comparative example, waviness B is also formed on the back surface 10b, following the waviness A on the surface 10a. In other words, in the embodiment of Figure 4B, both the surface 10a and the back surface 10b deviate from the ideal value. As a result, apparent waviness can be reduced, and the frequency variation can be made smaller than in the comparative example of Figure 4A.

[0044] While not limited to these values, the maximum height (Wz) of swells A and B is approximately 10 μm to 50 μm.

[0045] Another way to reduce waviness is to bring the surface 10a and back surface 10b closer to the ideal value shown in Figure 4B, that is, to form flat or curved surfaces with small waviness on both the surface 10a and back surface 10b, and to control the absolute value of the difference between the maximum and minimum values ​​of transmittance so that it falls within a predetermined range. However, in order to control the waviness A of the surface 10a to be small, the surface cannot be polished, so it is necessary to increase the yield while restricting the conditions of the manufacturing process, which tends to complicate the manufacturing process. Therefore, as shown in Figure 4B, it is preferable to reduce the apparent waviness by giving the back surface 10b a waviness B that follows the waviness A of the surface 10a. Accordingly, the following will describe a method in which both the surface 10a and back surface 10b are waviened in the same way to reduce the absolute value of the difference between the maximum and minimum values ​​of transmittance to fall within a predetermined range.

[0046] <Detailed explanation regarding the difference between the maximum and minimum transmittance values> This embodiment is characterized in that the absolute value of the difference between the maximum and minimum transmittance values ​​within a 40 mm square area in the center of the surface of the electrochromic element is within 0.3 D (diopters). The following explains the difference in transmittance, including experimental examples.

[0047] [Example 1] (1) Preparation of electrochromic film As shown in Figure 2A, an electrochromic film 2 was prepared, comprising a pair of substrates 3 and 4, electrode layers 5 and 6 arranged inside each substrate 3 and 4, and an electrochromic layer 7 sandwiched between each electrode layer 5 and 6. Polycarbonate sheets were used for the substrates 3 and 4, conductive sheets with ITO sputter-deposited film were used for the electrode layers 5 and 6, and an organic electrochromic material was used for the electrochromic layer 7.

[0048] (2) Preforming To match the three-dimensional curved surface of a spectacle lens with a transmittance of 0.00D, electrochromic film 2 was preformed into a curved shape (see Figure 2B). Preforming was performed by heating and shaping the film using a mold to match the curved surface of the lens.

[0049] (3) Fabrication of electrochromic elements Next, as shown in Figure 2C, the preformed electrochromic film 2 was set in the mold 20 of the injection molding machine, and polycarbonate constituting the lens substrate 1 was injected into the mold 20 to form the lens substrate 1 and obtain the electrochromic element 10 (see Figure 2D). It was confirmed that the electrochromic film 2 and the lens substrate 1 were in close contact without peeling off. When the electrochromic element 10 was visually observed from the concave side, an unnatural distortion was confirmed.

[0050] (4) Measurement of surface frequency distribution and creation of polishing data The surface reflectivity of the electrochromic element 10 was measured using a Dual Lensmapper (DLM) manufactured by Automation & Robotics. Figure 5A is a conceptual diagram of the surface frequency distribution (reflectivity distribution). The surface frequency distribution in Figure 5A is represented within a 40 mm square area in the center of the surface of the electrochromic element 10. Correction polishing data for the back surface was created using the measured surface frequency distribution values.

[0051] (5) Polishing the back surface Correction polishing data was input to a numerically controlled (NC) machining machine, and freeform polishing was performed on the back (concave) side. Existing techniques can be used for the freeform polishing method; for example, the polishing method disclosed in paragraph

[0044] of WO2009 / 048124 can be referenced. After freeform polishing, the electrochromic element was visually inspected from the back (concave) side and it was confirmed that there was no unnatural distortion.

[0052] (6) Measurement of transmittance The transmittance of electrochromic elements that had undergone freeform polishing was measured using a Dual Lensmapper (DLM). The measurement involved measuring the transmittance within a 40mm square area in the center of the electrochromic element's surface, and determining the maximum and minimum transmittance values. Note that, for both nearsighted (negative) and farsighted (positive) lenses, a larger numerical value indicates a higher prescription strength; therefore, the maximum and minimum prescriptions were summarized based on the strength of the prescription rather than the magnitude of the numbers. The absolute difference between the maximum and minimum transmittance values ​​was then calculated. In the experiment, a total of 12 electrochromic elements were fabricated using the same manufacturing method as described above, and the maximum, minimum, and absolute differences in transmittance values ​​for each element were determined. The results are shown in Table 1 below. The unit is D (diopter).

[0053] (7) Method for measuring maximum height swell (Wz) Three-dimensional mapping was performed within a 40mm square area in the center of the surface using a Bruker Dektak XT-A. The scan pitch was set to 0.1mm. Since the uncorrected measurement data overlapped with the curve shape of the eyeglass lenses, the data was corrected to be horizontal based on the theoretical values ​​of the lens design before calculating Wz. The results are shown in Table 2 below.

[0054] [Table 1]

[0055] [Table 2]

[0056] [Example 2] Except for setting the target power of the spectacle lenses to be fabricated from 0.00D to -2.00D, twelve electrochromic elements were fabricated using the same manufacturing method as in Example 1, and the maximum value of the transmittance, the minimum value of the transmittance, and the difference (absolute value) between them were determined for each electrochromic element. The results are shown in Table 3 below. The unit is D (diopter). The measurement results of the maximum height undulation (Wz) are shown in Table 4.

[0057] [Table 3]

[0058] [Table 4]

[0059] [Example 3] Except for setting the target power of the spectacle lenses to be fabricated from 0.00D to -4.00D, twelve electrochromic elements were fabricated using the same manufacturing method as in Example 1, and the maximum value of the transmittance, the minimum value of the transmittance, and the difference (absolute value) between them were determined for each electrochromic element. The results are shown in Table 5 below. The unit is D (diopter). The measurement results of the maximum height undulation (Wz) are shown in Table 6.

[0060] [Table 5]

[0061] [Table 6]

[0062] [Example 4] Except for setting the target power of the spectacle lenses to be fabricated from 0.00D to +4.00D, twelve electrochromic elements were fabricated using the same manufacturing method as in Example 1, and the maximum value of the transmittance, the minimum value of the transmittance, and the difference (absolute value) between them were determined for each electrochromic element. The results are shown in Table 7 below. The unit is D (diopter). The measurement results of the maximum height undulation (Wz) are shown in Table 8.

[0063] [Table 7]

[0064] [Table 8]

[0065] [Comparative Example 1] The target power of the spectacle lenses to be manufactured was set from 0.00D to -4.00D. Except for step (4) of Example 1, uncorrected polishing data not based on surface power distribution values ​​was used, and 12 electrochromic elements were manufactured using the same manufacturing method as in Example 1. The maximum value of the transmittance, the minimum value of the transmittance, and the difference (absolute value) between them were determined for each electrochromic element. The results are shown in Table 9 below. The unit is D (diopter). The measurement results of the maximum height waviness (Wz) are shown in Table 10.

[0066] [Table 9]

[0067] [Table 10]

[0068] [Comparative Example 2] The target power of the spectacle lenses to be manufactured was set from 0.00D to +4.00D. Except for step (4) of Example 1, uncorrected polishing data not based on surface power distribution values ​​was used, and twelve electrochromic elements were manufactured using the same manufacturing method as in Example 1. The maximum value of the transmittance, the minimum value of the transmittance, and the difference (absolute value) between them were determined for each electrochromic element. The results are shown in Table 11 below. The unit is D (diopter). The measurement results of the maximum height waviness (Wz) are shown in Table 12.

[0069] [Table 11]

[0070] [Table 12]

[0071] [Experimental Results] As shown in Tables 1, 3, 5, and 7, in Examples 1 to 4, the absolute difference between the maximum and minimum transmittance values ​​within a 40 mm square area in the center of the electrochromic element's surface was within 0.30 D. Furthermore, as shown in Tables 2, 4, 6, and 8, it was found that in Examples 1 to 4, the difference in maximum height waviness (Wz) between the front and back surfaces could be kept to 20 μm or less, preferably 10 μm or less.

[0072] On the other hand, as shown in Tables 9 and 11, in Comparative Example 1 and Comparative Example 2, the absolute value of the difference between the maximum and minimum transmittance was greater than 0.30 D. Also, as shown in Tables 10 and 12, in Comparative Example 1 and Comparative Example 2, the difference in maximum height waviness (Wz) between the front and back sides was approximately 40 μm or more.

[0073] In this example, the surface frequency distribution of the electrochromic element was measured (see Figure 5A), and based on the measurement results, the back surface of the lens substrate opposite to the side on which the electrochromic film was placed was polished. As a result, although the surface of the electrochromic film in this example also has undulation, the back surface also has undulation following the shape of the surface, thereby reducing the apparent undulation. As a result, the absolute value of the difference between the maximum and minimum values ​​of the transmittance was made smaller than in the comparative example. Figure 5B is a conceptual diagram of the transmittance distribution. Figure 5B shows the transmittance distribution within the eyeglass lens 30. Overall, it can be seen that the variation in transmittance was suppressed.

[0074] Based on the experimental results described above, a sample was deemed to qualify as an example if the absolute difference between the maximum and minimum transmittance values ​​was within 0.30D. When the value was within 0.30D, visual inspection of the electrochromic element from the back (concave) side revealed no unnatural distortion, indicating its applicability as an eyeglass lens. In contrast, the comparative example exhibited unnatural distortion, indicating its unsuitability as an eyeglass lens. The reason for setting the absolute difference between the maximum and minimum transmittance to within 0.30D is based on the tolerance for refractive power of single-vision spectacle lenses for refractive correction, as specified in JIS T 7313. From the perspective of spectacle lens design, the center power must satisfy the tolerance of the JIS standard, and therefore it was set to within 0.30D. A value of within 0.25D is preferable.

[0075] <Characteristic configuration of this embodiment> The electrochromic element 10 of this embodiment is an electrochromic element 10 in which a lens substrate 1 and an electrochromic film 2 are laminated, and is characterized in that the absolute value of the difference between the maximum and minimum values ​​of transmittance within a 40 mm square area in the center of the surface is within 0.30 D. As a result, apparent waviness can be reduced and the uniformity of the frequency distribution can be improved.

[0076] In this embodiment, it is preferable that the absolute value of the difference between the maximum and minimum transmittance values ​​within the entire 40 mm square area in the center of the surface is within 0.15 D. According to the experiments described above, many samples in Examples 1 to 4 fell within 0.15 D. Thus, in this embodiment, it is possible to control the value within 0.15 D, further improving the uniformity of the frequency distribution.

[0077] This embodiment is an electrochromic element 10 in which a lens substrate 1 and an electrochromic film 2 are laminated, characterized in that the surface of the electrochromic film 2 has a wavy shape, and the back surface of the lens substrate 1 is wavy in accordance with the shape of the surface. That is, as shown in the schematic diagram of Figure 4B, since the surface 10a and the back surface 10b are wavy in substantially the same shape, the absolute value of the difference between the maximum and minimum values ​​of transmittance within the entire 40 mm square area in the center of the surface can be adjusted to within 0.30 D, thereby reducing the apparent wavy shape.

[0078] In this embodiment, it is preferable that the back surface of the lens substrate 1 is polished to create a wavy surface that conforms to the shape of the surface. As shown in "(4) Measurement of surface frequency distribution and creation of polishing data" and "(5) Back surface polishing" of the above experiment, by polishing the back surface using corrected polishing data created using the numerical values ​​of the surface frequency distribution, the back surface can be polished to create a wavy surface that conforms to the shape of the surface, as shown in the schematic diagram of Figure 4B.

[0079] In this embodiment, it is preferable that the electrochromic film 2 is placed on the convex surface of the lens substrate 1, and the concave surface opposite the convex surface is polished. This allows for appropriate and easy polishing so that the back surface follows the shape of the surface, as shown in the schematic diagram of Figure 4B.

[0080] The eyeglass lens 30 in this embodiment is characterized by using the electrochromic element 10 described above. Furthermore, the eyeglasses 32 in this embodiment is characterized by using multiple eyeglass lenses 30. The electrochromic element 10 in this embodiment can reduce the power unevenness compared to conventional methods, so it can be effectively applied to eyeglass lenses, reducing the difference in power between the left and right lenses, and allowing the user to wear the eyeglasses without discomfort.

[0081] This embodiment is a method for manufacturing an electrochromic element 10, which is formed by laminating a lens substrate 1 and an electrochromic film 2. The method is characterized by measuring the surface frequency distribution of the electrochromic element 10 and, based on the measurement results, polishing the back surface of the lens substrate 1 on the side opposite to the side on which the electrochromic film 2 is placed. This reduces apparent waviness and allows for easy adjustment of the absolute value of the difference between the maximum and minimum transmittance within a 40 mm square area in the center of the surface to be within 0.30 D.

[0082] In this embodiment, it is preferable to measure the surface frequency distribution using reflectance, measure the polishing shape on the back surface based on the reflectance distribution, and polish the back surface according to the polishing shape. This allows the back surface to be polished in a way that follows the shape of the surface, as shown in the schematic diagram of Figure 4B.

[0083] In this embodiment, polishing is possible such that the absolute value of the difference between the maximum and minimum transmittance values ​​within the entire 40 mm square area in the center of the surface is within 0.30 D.

[0084] Furthermore, in this embodiment, it is preferable to have the following steps: forming the electrochromic element 10; placing the electrochromic film 2 in the mold 20 and injection molding the lens substrate 1; measuring the surface frequency distribution of the electrochromic element 10; and polishing the back surface based on the measurement results of the surface frequency distribution. That is, as shown in Figure 2C, in this embodiment, the electrochromic film 2 is placed in the mold 20 and injection molding the lens substrate 1, but the surface of the electrochromic film 2 is prone to warping after going through such a process. In the subsequent back surface polishing step, conventionally, polishing was performed using existing freeform polishing methods, but in this embodiment, the surface frequency distribution is measured, and then the back surface is polished based on the measurement results of the surface frequency distribution, so that the back surface can also form the same warping as the surface, and the apparent warping can be reduced. As a result, electrochromic elements with high uniformity of frequency distribution can be manufactured accurately and easily.

[0085] <Application> The electrochromic element of this embodiment is not limited to any particular application, but it can be preferably applied to photochromic eyeglass lenses.

[0086] The electrochromic element of this embodiment may be applied to applications other than eyeglass lenses. For example, electrochromic light-adjusting devices and anti-glare mirrors. [Industrial applicability]

[0087] The electrochromic element of the present invention can reduce undulation beyond the apparent level and minimize power variation. This allows the electrochromic element to be suitably applied to eyeglass lenses, eliminating distortion of the field of view when wearing eyeglasses.

[0088] This application is based on Japanese Patent Application No. 2022-074757, filed on April 28, 2022. All of its contents are included here.

Claims

1. An electrochromic element comprising a lens substrate and an electrochromic film laminated together, The surface of the electrochromic film opposite to the surface facing the lens substrate has a wavy surface. An electrochromic element characterized in that the back surface of the lens substrate opposite to the surface facing the electrochromic film is undulating to conform to the shape of the surface.

2. The electrochromic element according to claim 1, characterized in that the back surface of the lens substrate is polished and undulated to conform to the shape of the surface.

3. The electrochromic element according to claim 2, characterized in that the electrochromic film is arranged on the convex surface of the lens substrate, and the concave surface opposite to the convex surface is polished.

4. An eyeglass lens characterized by using the electrochromic element described in claim 1.

5. Eyeglasses characterized by using multiple eyeglass lenses as described in claim 4.

6. A method for manufacturing an electrochromic element comprising a lens substrate and an electrochromic film laminated together, The side of the electrochromic film opposite to the side facing the lens substrate is the surface of the electrochromic element. A method for manufacturing an electrochromic element, characterized by measuring the surface frequency distribution of the electrochromic element and, based on the measurement results, polishing the back surface of the lens substrate opposite to the side on which the electrochromic film is placed, so that it is wavy in accordance with the shape of the surface.

7. The method for manufacturing an electrochromic element according to claim 6, characterized in that the surface frequency distribution is measured by reflectance, the polishing shape of the back surface is measured based on the reflectance distribution so that the back surface is undulating in accordance with the shape of the surface, and the back surface is polished in accordance with the polishing shape.

8. A method for manufacturing an electrochromic element according to claim 6 or 7, characterized by polishing the surface so that the absolute value of the difference between the maximum and minimum values ​​of the transmittance within a 40 mm square area in the center of the surface is within 0.30 D.

9. The process of forming the electrochromic element, A step of placing the electrochromic element in a mold and injection molding the lens substrate, A step of measuring the surface frequency distribution of the electrochromic element, Based on the measurement results of the surface frequency distribution, a step of polishing the back surface, A method for manufacturing an electrochromic element according to claim 6 or 7, characterized by having the following features.

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