Any spell effect operating on a creature or unattended ob-
ject that passes through the screen is affected as by a targeted
dispel magic (PH 223) at your caster level. Attended items
that pass through are not affected by the screen, which is the only way the screen differs from a normal targeted casting of dispel magic—attended items are essentially not targeted by the screen. Make a caster level check (1d20 + 1 per caster level, maximum +10) to dispel spell effects (DC 11 + caster level) or suppress an unattended object’s magical properties for 1d4 rounds (DC equal to the item’s caster level). Spell ef-
fects not operating on objects or creatures cannot pass through the screen. A disintegrate or successful dispel magic removes
dispelling screen, while an antimagic field suppresses it.
Material Component: A sheet of fine lead crystal.
这个怎么判呢? 直接无效or dispel check?