A memory device , comprising: a substrate comprising a first substrate surface , a second substrate surface opposite to the first substrate surface , and a first lateral side and a second lateral side , which are arranged between the first substrate surface and the second substrate surface and opposite to each other, and further comprising: a storage module ; plural light-emitting elements disposed on the first substrate surface and the second substrate surface ; and a connection interface comprising a first connection part and a second connection part , wherein the first connection part and the second connection part are respectively disposed on the first substrate surface and the second substrate surface of the substrate , and the first connection part and the second connection part are located adjacent the first lateral side of the substrate and configured to be electrically connected to an electronic device; a heat dissipation structure partially connected with the substrate , at least one channel being formed between said heat dissipation structure and the substrate ; and a light guide element assembled with or locked on the heat dissipation structure , wherein the light guide element is located adjacent the second lateral side of the substrate , and separated from the plural light-emitting elements by the heat dissipation structure , and wherein the light guide element is configured so that after light beams generated by the plural light-emitting elements pass through the at least one channel, the light beams are centralized or distributed on the light guide element . a substrate comprising a first substrate surface , a second substrate surface opposite to the first substrate surface , and a first lateral side and a second lateral side , which are arranged between the first substrate surface and the second substrate surface and opposite to each other, and further comprising: a storage module ; plural light-emitting elements disposed on the first substrate surface and the second substrate surface ; and a connection interface comprising a first connection part and a second connection part , wherein the first connection part and the second connection part are respectively disposed on the first substrate surface and the second substrate surface of the substrate , and the first connection part and the second connection part are located adjacent the first lateral side of the substrate and configured to be electrically connected to an electronic device; a storage module ; plural light-emitting elements disposed on the first substrate surface and the second substrate surface ; and a connection interface comprising a first connection part and a second connection part , wherein the first connection part and the second connection part are respectively disposed on the first substrate surface and the second substrate surface of the substrate , and the first connection part and the second connection part are located adjacent the first lateral side of the substrate and configured to be electrically connected to an electronic device; a heat dissipation structure partially connected with the substrate , at least one channel being formed between said heat dissipation structure and the substrate ; and a light guide element assembled with or locked on the heat dissipation structure , wherein the light guide element is located adjacent the second lateral side of the substrate , and separated from the plural light-emitting elements by the heat dissipation structure , and wherein the light guide element is configured so that after light beams generated by the plural light-emitting elements pass through the at least one channel, the light beams are centralized or distributed on the light guide element . <EOS>