图片路径解析不了 php中的html

$html .= '   <div class="hd list04_hd">
<!--                        本级-->
                        <div class="btn">
                            <em class="js-categoryAdd addYq" data-type="yiyuan" style="background-image: url('."/static/admin/images/ico_add2.png".')"></em>
                            <em class="js-categoryEdit" style="background-image: url('."/static/admin/images/i-172.png".')"></em>
                        </div>
                        <input type="text" class="js-input editHosp" readonly value="'.$result['dept_name'].'" />
                    </div>';