Conventional　liquid　crystal　microlens　array　(LC　MLAs)　are　widely　used　in　integral　imaging　(II)　3D　displays　due　to　their　electrically　controllable　adjustable　focal　lengths.　However,　conventional　LC　MLAs　have　significant　challenges　to　obtain　a　large　depth-of-field　(DoF)　in　II　3D　displays.　This　paper　proposes　a　dual-focal　liquid　crystal　microlens　array　(DF-LC　MLAs)　to　improve　the　imaging　DoF.　The　dual-focal　characteristics　of　DF-LC　MLAs　are　primarily　attributed　to　the　periodically　stacked　high-resistance　layer　structure.　Compared　with　conventional　LC　MLAs,　the　proposed　DF-LC　MLAs　can　offer　two　controlable　modes　(operating　voltage　and　driving　frequency),　which　effectively　adjusts　the　focal　lengths　and　significantly　expanded　DoF　ranges.　The　experimental　results　indicate　that　the　DoF　range　for　conventional　LC　MLAs　changes　from　9.28　mm　to　3.13　mm　at　an　operating　voltage　of　3.6　V　when　the　driving　frequencies　vary　from　160　kHz　to　240　kHz,　while　that　of　DF-LC　MLAs　extends　from　34.87　mm　to　3.13　mm,　representing　an　increase　of　approximately　three　times.　Furtherly,　DF-LC　MLAs　applied　to　II　3D　displays　can　reconstruct　clearer　images　in　a　larger　DoF　range.　Based　on　these　results,　DF-LC　MLAs　exhibit　significant　advantages　in　II　3D　displays　due　to　their　DoF　extension　characteristics,　which　can　provide　some　new　ideas　and　possibilities　for　future　3D　display　technologies.　©　2024　Elsevier　B.V.