Convert CSV to JSON using PHP

I am trying to convert CSV file to JSON using PHP.

Here is my code

<?php 

date_default_timezone_set('UTC');
$today = date("n_j"); // Today is 1/23/2015 -> $today = 1_23

$file_name = $today.'.CSV'; // My file name is 1_23.csv
$file_path = 'C:\\Users\\bheng\\Desktop\\qb\\'.$file_name;
$file_handle = fopen($file_path, "r");

$result = array();

if ($file_handle !== FALSE) {

    $column_headers = fgetcsv($file_handle); 
    foreach($column_headers as $header) {
            $result[$header] = array();

    }
    while (($data = fgetcsv($file_handle)) !== FALSE) {
        $i = 0;
        foreach($result as &$column) {
                $column[] = $data[$i++];
        }
    }
    fclose($file_handle);
}

// print_r($result); // I see all data(s) except the header

$json = json_encode($result);
echo $json;

?>

print_r($result); // I see all data(s)

Then I json_encode($result); and tried to display it, but nothing is displaying on the screen at all. All I see is the blank screen, and 0 error message.

Am I doing anything wrong ? Can someone help me ?

Added Result of print_r($result);

Array (
    [Inventory] => Array (
        [0] => bs-0468R(20ug)
        [1] => bs-1338R(1ml)
        [2] => bs-1557G(no bsa)
        [3] => bs-3295R(no BSA)
        [4] => bs-0730R-Cy5"
        [5] => bs-3889R-PE-Cy7"
        [6] => 11033R
        [7] => 1554R-A647
        [8] => 4667
        [9] => ABIN731018
        [10] => Anti-DBNL protein 

        .... more .... 

Try like this:

$file="1_23.csv";
$csv= file_get_contents($file);
$array = array_map("str_getcsv", explode("\n", $csv));
$json = json_encode($array);
print_r($json);