custom font image

hey, i'm trying to have a custom font to display a single image. The image scale is 1024x1024 and it's store at  assets\minecraft\textures\fontand i have a json file name default.json who is stored at assets\minecraft\font\icon.png and who's containing : 
{
    "providers": [
        {
            "type": "bitmap",
            "file": "minecraft:font/icon.png",
            "ascent": 0,
            "height": 1024,
            "chars": [
                    "\uE001"
                ]
        }
    ]
}

but when i try to do /tellraw @a {"text":"\uE001"} i have a white scare. what did i do wrong ?