之前使用type来控制，发现不行，修改为password属性即可

  <van-fieldright-icon="{{passwordType == 'password'? 'closed-eye':'eye-o'}}"model:value="{{ password }}"password="{{passwordType == 'password' ? true: false}}"border="{{ false }}"custom-class="password_style {{focusPassword ? 'blue':'none'}}"bind:click-icon="onClickIcon"focus="{{focusPassword}}"/>