An electronic device may have a housing. Input-output devices may be mounted in the housing. The input-output devices may include a display with an array of pixels configured to display images for a user. The electronic device may have an optical component formed under a transparent region in the housing. The transparent region may be associated with an opening in an opaque masking layer in an inactive area of the display or other portion of the electronic device. A diffuser may be formed between the optical component and the transparent region. The diffuser may have a polymer layer with embedded thin-film interference filter flakes configured to scatter light and to exhibit desired reflection and transmission spectral.