METHOD FOR MANUFACTURING TRANSMISSION TYPE OPTICAL ELEMENT

• Main Authors: SAWAGUCHI TAICHI, SUDEJI HIRONARI
• Format: Patent
• Language: English; Japanese
• Published: 09.07.2020
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

To provide a method capable of suppressing the displacement of relative positions between one molding surface and the other molding surface when forming a transmission type optical element such as a lens by hot-press molding a thermoplastic resin film.SOLUTION: The method for manufacturing a transmission type optical element includes steps of: hot-pressing for obtaining a hot-press film by hot-pressing a thermoplastic resin film formed with use of a thermoplastic resin using at least a pair of flat molds in a temperature more than the glass transition temperature of the thermoplastic resin; mold cooling for cooling the hot-press film by cooling the flat molds to a temperature less than or equal to the glass transition temperature of the thermoplastic resin; and demolding, after the mold cooling step, for demolding the cooled hot-press film from the flat molds to obtain a molded film including at least one transmission type optical element. The thermal expansion coefficient of the flat-molds is 6 ppm/K or less.SELECTED DRAWING: Figure 1 【課題】熱可塑性樹脂フィルムを熱プレス成形してレンズ等の透過型光学素子を形成する際に一方の成形面と他方の成形面との相対位置にズレが生じるのを抑制することが可能な方法を提供する。【解決手段】熱可塑性樹脂を用いて形成された熱可塑性樹脂フィルムを、少なくとも一対の平板金型により熱可塑性樹脂のガラス転移温度超の温度で熱プレスして熱プレスフィルムを得る熱プレス工程と、平板金型を熱可塑性樹脂のガラス転移温度以下の温度まで冷却して、熱プレスフィルムを冷却する金型冷却工程と、金型冷却工程の後に、冷却された熱プレスフィルムを平板金型から離型して少なくとも１つの透過型光学素子を含む成形フィルムを得る離型工程とを含み、平板金型の熱膨張係数が６ｐｐｍ／Ｋ以下である、透過型光学素子の製造方法。【選択図】図１