ELEMENT SUBSTRATE AND LIQUID DISCHARGE HEAD

To provide an element substrate which can improve a heat radiation property of a heating resistor even when a member arranged on a lower side of the heating resistor is flattened.SOLUTION: An element substrate 100 includes a base material 10, a heat storage/radiation layer 13 laminated on the base material 10, a heating resistor 15 laminated on the heat storage/radiation layer 13, and a pair of connection wiring 12a, 12b which are buried in the heat storage/radiation layer 13 and are connected to the heat resistor 15. A sum of heat radiation action areas 23a, 23b extending in a direction mutually separating from end parts on mutual opposite sides of connection areas connected to the connection wiring 12a, 12b respectively in the heating resistor 15 is at least ten times larger than a sum of areas of the connection areas 12a, 12b.SELECTED DRAWING: Figure 1 【課題】発熱抵抗体の下側に設けられる部材が平坦化されている場合であっても、発熱抵抗体の放熱性を向上させることが可能な素子基板を提供する。【解決手段】素子基板１００は、基材１０と、基材１０に積層された蓄放熱層１３と、蓄放熱層１３に積層された発熱抵抗体１５と、蓄放熱層１３に埋設され、かつ、発熱抵抗体１５と接続された１対の接続配線１２ａおよび１２ｂとを有する。発熱抵抗体１５における接続配線１２ａおよび１２ｂのそれぞれと接続する接続領域の互いに反対側の端部から互いに離れる方向に延びる放熱作用領域２３ａおよび２３ｂの合計は、接続領域１２ａおよび１２ｂの面積の合計の１０倍よりも大きい。【選択図】図１