Electrochromic elements, eyeglass lenses, eyeglasses, and molds

Abstract

The purpose of the present invention is to provide an electrochromic element, an eyeglass lens, and the like in which a difference between reflection strengths is adjusted to control waviness. An electrochromic element (10) according to the present invention is obtained by laminating a lens substrate (1) and an electrochromic film (2), the electrochromic element being characterized in that: the absolute value of a difference between reflection strengths in 30% or more of adjacent local regions, among local regions obtained by dividing the electrochromic element into 5-mm squares within a range of a 40-mm square from the center of the surface of the electrochromic element, is 0.05-0.5 D inclusive; the surface of the electrochromic film is wavy; and the highest waviness (Wz) in 30% or more of the regions among the local regions obtained by dividing the electrochromic element into 5-mm squares within a range of a 40-mm square from the center of the surface of the electrochromic element is 6-30 μm inclusive.

Description

Technical Field

[0006] , ,

[0005] , ,

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

Background Art

[0002] An electrochromic element utilizing an electrochromism phenomenon that reversibly causes an oxidation-reduction reaction by applying a voltage and reversibly changes color 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 an injection molding of a lens substrate is performed. 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] The heating conditions during the above-described preforming and injection molding are, for example, 100°C or higher, and unevenness occurs on the surface of the electrochromic element due to the influence of heat. The unevenness appears as shading on the surface when the electrochromic element is colored by passing an electric current through it.

[0006] However, conventional methods did not control surface undulation. As a result, depending on the undulation, the difference in shade on the surface became large. Furthermore, when electrochromic elements were applied to eyeglass lenses, a large difference in shade occurred between the left and right lenses, resulting in product defects.

[0007] The present invention aims to solve the above problems and to provide an electrochromic element and eyeglass lens in which the undulation is controlled by adjusting the difference in reflectivity and the maximum height undulation to a predetermined range. Furthermore, the present invention aims to provide eyeglasses with reduced left-right differences in tint by using eyeglass lenses in which the absolute value of the difference in reflectivity and the maximum height undulation are adjusted to be within a predetermined range. Furthermore, the present invention aims to provide a mold used in the manufacture of electrochromic elements. [Means for solving the problem]

[0008] 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 side of the electrochromic film opposite to the side facing the lens substrate The absolute value of the difference in reflectivity between adjacent local regions, each of which is divided into 5mm squares within a 40mm square area in the center of the surface, is 0.05D or more and 0.5D or less, and the surface of the electrochromic film has undulation. Furthermore, the maximum height waviness (Wz) in 30% or more of each local region obtained by dividing the 40 mm square area in the center of the surface into 5 mm squares is between 6 μm and 30 μm. , characterized by 。

[0009] In one aspect of the present invention, it is preferable that the absolute value of the difference in reflectance between adjacent local regions, each local region comprising 50% or more of the aforementioned local regions, is 0.05D or more and 0.5D or less.

[0010] In one aspect of the present invention, it is preferable that the absolute value of the difference in reflectance is 0.1D or more and 0.5D or less.

[0011] An eyeglass lens according to one aspect of the present invention is characterized by using the electrochromic element described above. One embodiment of the present invention is characterized by using a plurality of the above-described eyeglass lenses.

[0012] One aspect of the present invention is a mold for manufacturing an electrochromic element comprising a lens substrate and an electrochromic film laminated together, comprising a first mold and a second mold, The electrochromic element can be manufactured by placing the electrochromic film in contact with the inner surface of the first mold, and injection molding the material constituting the lens substrate into the cavity between the first mold and the second mold, thereby joining the lens substrate and the electrochromic film, and the inner surface of the first mold in contact with the electrochromic film has a wavy surface. Furthermore, the maximum height waviness (Wz) in 30% or more of each local region obtained by dividing the 40 mm square area in the center of the inner surface of the first mold into 5 mm squares is between 6 μm and 30 μm. Characterized by 。 [Effects of the Invention]

[0013] According to the electrochromic element of the present invention, the difference in reflectivity and the maximum height fluctuation can be adjusted to a predetermined range, thereby suppressing the difference in density. Furthermore, when the electrochromic element is applied to eyeglasses, the difference in density between the left and right eyes can be reduced, improving the yield. [Brief explanation of the drawing]

[0014] [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 the experimental result of the reflectance of each local area in the example, and is a conceptual diagram showing each local area obtained by dividing a 40 mm square range on the central surface of the electrochromic element into 5 mm squares. [Figure 5B] It is the experimental result of the reflectance of each local area in the example, and shows the reflectance of each local area obtained by dividing a 40 mm square range on the central surface of the electrochromic element into 5 mm squares. [Figure 6] It is a table showing the difference in reflectance between adjacent local areas obtained from the reflectance of each local area in FIG. 5B. [Figure 7] Shows the experimental results of the reflectance of each local area in the comparative example. [Figure 8] It is a table showing the difference in reflectance between adjacent local areas obtained from the reflectance of each local area in FIG. 7.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail.

[0016] <The electrochromic element 10 in this embodiment> FIG. 1 is a schematic cross-sectional 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.

[0017] [Lens base material 1] The lens substrate 1 is required to be transparent and have high transmittance. The material of the lens substrate 1 is not limited, but examples include moldable resin substrates such as polycarbonate resin, acrylic resin, epoxy resin, and phenolic resin, as well as glass substrates. Of these, the lens substrate 1 is preferably made of polycarbonate resin from the viewpoint of moldability and manufacturing cost.

[0018] [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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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. 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.

[0024] <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. 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] <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.

[0030] 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.

[0031] 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.

[0032] Incidentally, when an electrochromic element was applied to eyeglasses 32 as an eyeglass lens 30 and an electric current was passed through it to color the lenses as sunglasses, variations in shade sometimes appeared on the lens surface. It was found that the degree of variation in shade increased depending on the size of the undulation on the lens surface.

[0033] The waviness occurs when heat is applied to the electrochromic film 2 during the manufacturing process of the electrochromic element 10. While the heating temperature is not limited, for example, heat of 100°C or higher acts on the electrochromic film 2. Also, while the heating process is not limited, as shown in Figures 2B and 2C, there are processes such as preforming the electrochromic film 2 into a three-dimensional shape, and molding the electrochromic film 2 in a mold 20 and injection molding the lens substrate 1.

[0034] Figures 4A and 4B are conceptual diagrams showing the surface curvature of each spectacle lens 30 when a pair of spectacle lenses 30 are placed on the left and right sides of a spectacle frame. Figure 4A shows a comparative example, and Figure 4B shows an embodiment. Note that the curvature is exaggerated in Figures 4A and 4B.

[0035] As shown in the comparative example in Figure 4A, for example, if the waviness A of the left eyeglass lens is very small and the waviness B of the right eyeglass lens is very large, different shades of gray will appear on the left and right sides, resulting in a defective product. Conventionally, because the waviness is not controlled, different shades of gray tend to appear on the left and right sides, leading to a decrease in yield.

[0036] Therefore, after diligent research, the inventors have succeeded in controlling the undulation by adjusting the difference in reflectivity to a predetermined range. In other words, this embodiment is characterized by having undulation on the surface of the electrochromic film, and furthermore, by adjusting the difference in reflectivity to a predetermined range, the difference in density appearing on the surface of the electrochromic film is suppressed, and the variation in density appearing on each lens is reduced.

[0037] In other words, as shown in the embodiment in Figure 4B, undulations C and D are formed on the surfaces of the left and right eyeglass lenses, but undulations C and D are smaller than undulation B in the comparative example shown in Figure 4A. This makes it possible to suppress the difference in density that appears on the surface. Also, as shown in Figure 4B, the variation between undulation C and undulation D is smaller than the variation between undulation A and undulation B shown in Figure 4A, and is closer to uniformity. Therefore, in the embodiment in Figure 4B, the difference in density between the left and right lenses can be reduced compared to the comparative example in Figure 4A, and the yield can be improved.

[0038] <Detailed explanation regarding the difference in reflectivity> In this embodiment, it is preferable that the absolute value of the difference in reflectivity between adjacent local regions, each of which is divided into 5mm squares within a 40mm square area in the center of the electrochromic element's surface, is 0.05D or more and 0.5D or less. The following explains the difference in reflectivity, including experimental examples.

[0039] [Example 1] (1) Manufacturing of molds for injection molding The material used for the injection molding die 20 shown in Figure 2C was STAVAX mold steel. In this case, electrochromic elements with a central thickness of approximately 2.0 mm for eyeglass lenses could be injection molded, and the die 20 was prepared with a first die 21 (convex base die) corresponding to the convex surface of a spherical lens with a reflectivity of -2.0 D (diopter), and a corresponding second die 22 (concave die).

[0040] (2) Processing of micro-ripples (textured surface) A convex base mold was set in a micro-curved surface forming device equipped with a triangular cap-shaped (or spherical or inverted round) diamond bit having a cutting diameter of approximately 0.5 mm to 10 mm (preferably several mm to approximately 5 mm). The micro-curved surface forming device is similar in configuration to a milling machine with an automatic rotation mechanism. At this time, the convex base mold was set in the micro-curved surface forming device so that the center of the convex base mold, i.e., the center of the finished lens, was the center of the texturing process. The tip of the diamond bit was then applied to the convex base mold at a position approximately 0.5 mm to 5 mm (preferably several mm) outward from the center of the inner surface, such that the load was within the range of approximately 0.01 to 0.50 kgf. The load is preferably a few tenths of a kgf to approximately 0.50 kgf.

[0041] The convex base mold was rotated at a rotational speed of approximately 1 rpm to 100 rpm, and the load of the diamond bit was linearly changed over 5 to 300 seconds, ranging from -1% to -100% of a set value. Subsequently, the load was linearly returned from the reduced load to the initial load over 5 to 300 seconds. This sequence was executed for approximately 1 to 15 minutes to polish the inner surface of the convex base mold. The rotational speed is preferably around several tens of rpm. The load is preferably changed linearly between the initial value and 0 rpm to several rpm. The linear change in load is preferably performed over several seconds to several tens of seconds. The polishing time is preferably several minutes to about 5 minutes.

[0042] Subsequently, a diamond bit was applied to an outer position of 0.5 mm to 15 mm (preferably a few mm), and the same procedure as above was repeated to create a textured surface on the inner surface of the convex base mold. After that, the inner surface was buffed to round off the edges of the cutting and polishing. The textured surface was set so that the maximum cross-sectional height (Rt) was 30 μm or less. A mold with the textured surface as described above will be referred to as a "convex textured mold" below.

[0043] (3) Injection molding For injection molding, an α100iA (manufactured by FANUC: clamping force 100t, injection force 50t) was used, and lens substrates were injection molded using a convex textured mold and a concave mold. An electrochromic film, which had been curved by preforming, was set on the inner surface of the convex textured mold, and polycarbonate with bisphenol A as the main ingredient was injected. It was confirmed that the electrochromic film adhered to the injected polycarbonate. In addition, the excess electrochromic film was cut off with a utility knife.

[0044] (4) Lens polishing process The concave surface of the electrochromic element created in the previous step was cut and polished using a freeform curve generator. The finished product was a planar lens with a central thickness of 2.0 mm.

[0045] (5) Electrode wiring Electrode wiring was added to the electrode portion for power extraction of the electrochromic film of the aforementioned plano lens.

[0046] (6) Cutting and edge processing An electrochromic element with electrode wiring was cut and edge-processed to incorporate it into an eyeglass frame, thereby obtaining an eyeglass lens. In this embodiment, round test frames with the same diameter of 50 mm were used for both eyes to allow for comparison of differences between the left and right eyes. The eyeglass lens was then incorporated into the frame and connected to the frame's power wiring. In addition to the power wiring, the frame is equipped with a power switch and a battery.

[0047] (7) Experimental method and evaluation of the difference in reflectance The reflectance distribution of the electrochromic element fabricated as described above was measured using a dual-lens mapper.

[0048] As shown in Figure 5A, the reflectance distribution was measured in a 40mm x 40mm area centered on the convex surface of the electrochromic element. This measurement area was then divided into 64 sections of 8x8 grids. Each section is referred to as a "local area," and each local area is 5mm square.

[0049] As shown in Figure 5A, a total of 64 local regions were numbered from 1 to 64. The average reflectance of each local region was then measured using a dual-lens mapper. The measurement results are shown in Figure 5B. The unit is D (diopter).

[0050] Next, the difference in reflectance between adjacent local regions was calculated. Figure 6 is a table showing the difference in reflectance between adjacent local regions. There are a total of 112 adjacent local regions (boundaries). In Figure 6, these are represented as "Adjacent No."

[0051] As shown in Figure 6, for example, adjacent area No. 1 represents the difference in reflectivity between the local area labeled 1 and the local area labeled 2, as shown in Figure 5A. As shown in Figure 5B, the average reflectivity of the local area labeled 1 was -2.00D, and the average reflectivity of the local area labeled 2 was -1.40D. Therefore, as shown in Figure 6, the difference in reflectivity for adjacent area No. 1 was -0.60D. In this way, the difference in average reflectivity for all adjacent areas from No. 1 to No. 112 was calculated.

[0052] Furthermore, if the difference in reflectance was within the range of 0.05D to 0.5D in absolute value, the evaluation was marked as ○, and if it was outside this range, the evaluation was marked as ×. In Example 1, out of 112 samples, 34 had a difference in reflectance within the range of 0.05D to 0.5D in absolute value, and it was found that the condition was met in more than 30% of adjacent local regions. It was also found that the average reflectance was within ±0.2D of the design value. The difference in reflectance contributes to the waviness of the electrochromic film surface. The greater the waviness, the greater the difference in reflectance. As in this example, by keeping the difference in reflectance within the range of 0.05D to 0.5D in absolute value, it is possible to control the waviness formed within a 40mm square area in the center of the surface to be appropriately small and the waviness pitch to be approximately constant.

[0053] (8) 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 1 below.

[0054] [Table 1]

[0055] As shown in Table 1, the proportion of maximum height swells (Wz) between 6 μm and 30 μm was 38%. (9) Sensory evaluation when applied to eyeglasses The eyeglasses using the electrochromic element from Example 1 were energized, and the coloration of the left and right lenses was visually evaluated after 5 minutes of continuous energization. Upon checking for any difference in coloration between the left and right lenses, no particular discomfort was observed, and the color density was uniform in both lenses, confirming that the eyeglasses were suitable. Furthermore, when the eyeglasses were actually worn and the distortion of the field of vision was checked, no particularly significant difference was felt between the left and right lenses.

[0056] [Example 2] In Example 2, electrochromic elements and eyeglasses were manufactured under the same conditions as in Example 1, except that the initial load for texturing was set to 0.03 to 0.10 kgf. In Example 2, the initial load for texturing was set lower than in Example 1. Similar to Example 1, when the absolute value of the difference in reflectivity between adjacent local regions was measured, it was found that more than 50% fell within the range of 0.05 D to 0.5 D. When applied to eyeglasses and a sensory evaluation similar to that in Example 1 was performed, there was no significant difference in the difference in density between the left and right lenses, nor was there any particularly significant difference in the distortion of the field of view when wearing the eyeglasses. Table 2 shows the measurement results for the maximum height swell (Wz) in Example 2.

[0057] [Table 2]

[0058] As shown in Table 2, the proportion of maximum height swells (Wz) between 6 μm and 30 μm was 50%.

[0059] [Comparative Example] In the comparative example, the electrochromic element and eyeglasses were manufactured under the same conditions as in Example 1, except that the initial load was changed to 0.55-0.9 kgf so that the initial load for texturing was greater than in Example 1. Table 3 shows the measurement results of the maximum height swell (Wz) for the comparative example.

[0060] [Table 3]

[0061] As shown in Table 3, the proportion of maximum height swells (Wz) between 6 μm and 30 μm was 13%.

[0062] Figure 7 shows the measurement results of reflectance in 64 local regions, each 5 mm square, obtained by dividing a 40 mm x 40 mm area centered on the convex surface of the electrochromic element. Figure 8 shows the calculation results of the difference in reflectance between adjacent local regions. The local region numbers correspond to those in Figure 5A.

[0063] As shown in Figure 8, if the difference in reflectance was within the range of 0.05D to 0.5D in absolute value, it was evaluated as ○, and if it was outside this range, it was evaluated as ×. In the comparative example, out of 112 samples, 25 had a difference in reflectance within the range of 0.05D to 0.5D in absolute value, and it was found that this was less than 30% between adjacent local regions. In addition, the average reflectance exceeded ±0.2D of the design value.

[0064] When the electrochromic element of the comparative example was applied to eyeglasses and the eyeglasses were evaluated under the same conditions as in Example 1, unevenness in density was observed between the left and right lenses, and significant distortion of the field of view was also observed. Therefore, it was found that the electrochromic element of the comparative example cannot be used in eyeglasses.

[0065] In this embodiment, in addition to the absolute value of the difference in reflectivity described above, the following configuration is achieved. Specifically, in this embodiment, the surface of the electrochromic film 2 has undulations, and the maximum height undulation (Wz) in 30% or more of each local region obtained by dividing the 40 mm square area in the center of the surface into 5 mm squares is between 6 μm and 30 μm. Both Examples 1 and 2 have been confirmed to satisfy this numerical range. In this embodiment, the maximum height undulation (Wz) of the undulations formed on the surface of the electrochromic film 2 can be controlled, and the difference in density that appears on the surface when the electrochromic element is operating can be reduced. Furthermore, when applied to eyeglasses, the variation in density that appears in the left and right lenses can be reduced, and there is no distortion of the field of view when worn, making it effective for application to eyeglasses.

[0066] <Characteristic configuration of this embodiment> The electrochromic element 10 of this embodiment is an electrochromic element in which a lens substrate 1 and an electrochromic film 2 are laminated, and the absolute value of the difference in reflectivity between adjacent local regions of 30% or more of each local region obtained by dividing the 40 mm square area in the center of the surface into 5 mm squares is 0.05 D or more and 0.5 D or less, and the surface of the electrochromic film 2 has undulation. In this embodiment, it is preferable that the maximum height undulation (Wz) in 30% or more of each local region obtained by dividing the 40 mm square area in the center of the surface into 5 mm squares is 6 μm or more and 30 μm or less. More preferably, the above numerical range is satisfied in 35% or more of the region.

[0067] This embodiment is characterized by having undulations on the surface of the electrochromic element 10, and preferably, these undulations are controlled by adjusting the absolute value of the difference in reflectivity. That is, in this embodiment, by adjusting the absolute value of the difference in reflectivity between adjacent local regions of 30% or more within each local region to a range of 0.05D to 0.5D, the undulations can be controlled to be appropriately small and the pitch of the undulations to be approximately constant. As a result, when the electrochromic element 10 is applied to eyeglasses 32 as an eyeglass lens 30, the difference in density between the left and right lenses can be reduced, and there is no distortion of the field of view when worn, making it effective for use in eyeglasses. However, making the difference in reflectivity below 0.05D in absolute value imposes too many constraints on manufacturing conditions, making stable adjustment difficult and impractical. Also, if the proportion of the difference in reflectivity exceeding 0.5D in absolute value becomes large, as in the comparative example above, the unevenness in density becomes large and impractical. In this embodiment, while allowing for some waviness, stable manufacturing can be achieved and unevenness in density can be suppressed. In this embodiment, the absolute value of the difference in reflectivity is adjusted to a range of 0.05D to 0.5D.

[0068] Furthermore, in this embodiment, as described above, the surface of the electrochromic film 2 has undulations, and the maximum height undulation (Wz) in more than 30% of each local region obtained by dividing the 40 mm square area in the center of the surface into 5 mm squares is between 6 μm and 30 μm. In this way, in this embodiment, the maximum height undulation (Wz) of the undulations formed on the surface of the electrochromic film 2 can be controlled, and the difference in density that appears on the surface when the electrochromic element is operating can be reduced. When applied to eyeglasses, the variation in density that appears in the left and right lenses can be reduced, and there is no distortion of the field of view when worn, making it effective for application to eyeglasses.

[0069] Furthermore, in this embodiment, it is preferable that the absolute value of the difference in reflectivity between adjacent local regions, each local region comprising 50% or more of the region, is 0.05D or more and 0.5D or less. This corresponds to Example 2 described above. This makes it possible to more effectively reduce the difference in density that appears on the surface when the electrochromic element is in operation.

[0070] Furthermore, in this embodiment, it is more preferable that the absolute value of the difference in reflectance is between 0.1D and 0.5D. In Example 2, it was confirmed that the absolute value of the difference in reflectance between 30% or more adjacent local regions was within the range of 0.1D and 0.5D.

[0071] Furthermore, in this embodiment, the mold 20 for manufacturing an electrochromic element 10 formed by laminating a lens substrate 1 and an electrochromic film 2 comprises a first mold 21 and a second mold 22, wherein the electrochromic film 2 is placed in contact with the inner surface of the first mold 21, and the material constituting the lens substrate 1 is injection molded in the cavity between the first mold 21 and the second mold 22. At this time, the inner surface of the first mold 21 in contact with the electrochromic film 2 is characterized by having undulations, and preferably, the maximum height undulation (Wz) in 30% or more of each local region obtained by dividing the 40 mm square area in the center of the inner surface into 5 mm squares is 6 μm or more and 30 μm or less. By manufacturing the electrochromic element 10 using this mold, the undulations formed on the surface of the electrochromic film 2 can be controlled to be appropriately small and the undulation pitch to be approximately constant.

[0072] <Application> The electrochromic element of this embodiment is not limited to any particular application, but it can be preferably applied to photochromic eyeglass lenses. 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]

[0073] The electrochromic element of the present invention controls the undulation formed on its surface by adjusting the absolute value of the difference in reflectivity and the maximum height of the undulation. This reduces the difference in surface density that occurs when the electrochromic element is in operation. In particular, when the electrochromic element is applied to eyeglasses, it can reduce the variation in density that appears in the left and right lenses, and can be effectively applied to eyeglasses without distortion of the field of view when worn.

[0074] This application is based on Japanese Patent Application No. 2022-076852, filed on May 9, 2022. All of its contents are included here.

Claims

1. An electrochromic element comprising a lens substrate and an electrochromic film laminated together, The absolute value of the difference in reflectivity between adjacent local regions, each of which is divided into 5mm squares within a 40mm square area in the center of the surface of the electrochromic film opposite to the side facing the lens substrate, is 0.05D or more and 0.5D or less. The surface of the electrochromic film has a wavy surface. The maximum height waviness (Wz) in 30% or more of each local region obtained by dividing the 40 mm square area in the center of the surface into 5 mm squares is between 6 μm and 30 μm. An electrochromic element characterized by the above.

2. The electrochromic element according to claim 1, characterized in that the absolute value of the difference in reflectivity between 50% or more adjacent local regions is 0.05 D or more and 0.5 D or less.

3. The electrochromic element according to claim 1 or 2, characterized in that the absolute value of the difference in reflectance is 0.1 D or more and 0.5 D or less.

4. An eyeglass lens characterized by using an electrochromic element as described in claim 1 or claim 2.

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

6. A mold for manufacturing an electrochromic element comprising a lens substrate and an electrochromic film laminated together, It has a first type and a second type, The electrochromic element can be manufactured by placing the electrochromic film in contact with the inner surface of the first mold, and injection molding the material constituting the lens substrate into the cavity between the first mold and the second mold, thereby joining the lens substrate and the electrochromic film. The inner surface in contact with the electrochromic film of the first type has a wavy surface, The maximum height waviness (Wz) in 30% or more of each local region obtained by dividing the 40 mm square area in the center of the inner surface of the first mold into 5 mm squares is between 6 μm and 30 μm. A mold characterized by the following features.

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