Pattern-formed object, injection molded object, and method of manufacturing injection molded object

A method of manufacturing an injection molded object, the method comprising:

• preparing a flat metal sheet having a first surface and a second surface opposite to the first surface, the first surface having a pattern thereon formed by projections and depressions;
• fixing the metal sheet onto a mold for injection molding with the first surface of the metal sheet facing a cavity of the mold and a space provided between a portion of the second surface and a bottom of an inner surface of the mold;
• clamping the mold;
• forming the injection molded object by injecting molten plastic into the cavity, pressing the portion of the second surface against the bottom of the inner surface of the mold by pressure of the molten plastic, such that the metal sheet is plastically deformed to be in close contact with the inner surface of the mold, and transferring the pattern formed on the first surface onto a product surface of the molten plastic;
• and
• ejecting the injection molded object after the molten plastic solidifies, with the metal sheet remaining in close contact with the inner surface of the mold.