This　Letter　proposes　the　use　of　atomic　layer　deposition　(ALD)　encapsulation　as　a　stability-improving　approach　for　a　quantum-dot　micro-structural　array　(QDMA)　with　a　random　rough　interface.　The　QDMA　is　first　prepared　by　screen　printing　technology　on　an　edge-lit　light-guide　plate　(LGP)　for　backlight　application.　A　flexible　aluminum　oxide　film　is　then　densely　deposited　onto　the　rough　surface　of　the　QDMA.　The　influences　of　two　key　factors,　the　reaction　temperature　and　deposition　thickness,　on　the　encapsulation　effect　and　output　performance　of　this　QD　backlight　are　discussed.　After　ALD　encapsulation,　the　water　vapor　transmission　rate　was　measured　to　be　less　than　0.014　g/(m2　day).　The　average　luminance　of　the　encapsulated　QD　backlight　remained　stable　after　continuous　working　for　200　h,　while　an　unencapsulated　QD　backlight　lost　over　50%　of　its　initial　luminance.　The　complete　attenuation　trend　for　the　encapsulated　QD　backlight　was　analyzed　in　a　more　demanding　testing　environment,　and　results　showed　that　80%　(＞3000　cd/m2)　of　the　initial　luminance　was　maintained　after　250　h　at　a　high　temperature　of　70　°C　and　a　relative　humidity　of　90%.　The　mechanism　behind　these　experimental　results　is　also　discussed.　©　2021　Optica　Publishing　Group