36．已知函数$f(x)=\left\{{\left.\begin{array}{l}{\frac{2^x}{4}-2,x\geqslant a,}\\ {{x^2}-3x+2,x<a\cdot }\end{array}\right.}\right.$若$f(x)$恰有2个零点，则实数$a$的取值范围是 ___$(1$[，]$2]\bigcup (3,+\infty )$___．