ถามเรื่อง preg_replace กับการค้นหาเครื่องหมายอักขระพิเศษ

header("Content-type:text/html; charset=tis-620"); 
header("Cache-Control: no-store, no-cache, must-revalidate"); 
header("Cache-Control: post-check=0, pre-check=0", false); 
$link=mysql_connect("localhost","root","xxxxxx") or die("Error Connect to DB");
 mysql_select_db("xxxxx");
 mysql_query("SET NAMES tis620");
$q = urldecode($_GET["q"]);
$q= iconv('tis-620', 'utf-8', $_GET['q']);
$q= iconv('utf-8', 'tis-620', $_GET['q']);
//echo "$q";
mb_http_input('tis-620');
mb_language('uni');
mb_regex_encoding('UTF-8');
ob_start('mb_output_handler');
setlocale(LC_ALL, 'th_TH');

$pagesize = 10; 
$table_db=" claim_item"; 
$find_field="itemname"; 
$sql = "select * from $table_db  where locate('$q', $find_field) > 0 order by locate('$q', $find_field), $find_field limit $pagesize";
$results = mysql_query($sql);
while ($row = mysql_fetch_array( $results )) {
$id = $row["itemcode"];
$name =$row["itemname"];
'  
$name = str_replace("'", "'", $name);
//$name = str_replace("(", "", $name);
//$name = str_replace(")", "", $name);
//$name = str_replace("/", "", $name);
$display_name = preg_replace("/(" . $q . ")/i", "<b>$1</b>", $name);  
echo "<li onselect=\"this.setText('$name').setValue('$id');\">$display_name</li>";
}
mysql_close();