Molded product and method for manufacturing same

A method for manufacturing a molded product having a phase structure, comprising a matrix formed of a photopolymerizable composition, and multiple columnar structures disposed within said matrix and having an index of refraction different from said matrix, comprising:

• a step for injecting a photopolymerizable composition containing a photopolymerizable monomer or oligomer and a photoinitiator into a mold;
• a step for disposing a photomask having light-transmissive regions and a light non-transmissive region between the mold and a light source;
• a first light irradiation step for irradiating parallel light from the light source with a wavelength full width at half maximum of 100 nm or less and an essentially uniform light intensity distribution through the photomask toward the photopolymerizable composition within the mold to polymerize those sites within the photopolymerizable composition which are irradiated with parallel light into an incompletely polymerized state;
• and
• a second light irradiation step for irradiating parallel light with a wavelength full width at half maximum of 100 nm or less and an essentially uniform light intensity distribution toward the photopolymerizable composition within the mold after removing the photomask to complete the polymerization of the photopolymerizable composition.