A display module includes a display panel including two substrates and a display medium sandwiched between the two substrates, a wavelength modulation unit including a carrier substrate and a wavelength modulation layer on the carrier substrate, the carrier substrate having a coefficient of thermal expansion substantially matching coefficients of thermal expansion of the two substrates, an adhesive layer bonding the display panel and the wavelength modulation unit to form a space between the display panel and the wavelength modulation unit, and an optical film interposed in the space to be clamped between the display panel and the wavelength modulation unit.