The electron gun for a large screen color picture tube generally employs quadrupole lens, so that the landing spot with positive astigmatism can cancel the negative astigmatism from the deflection magnetic field in certain sense.
英
美
- 大屏幕彩色顯像管電子槍通常采用非軸對稱(chēng)四極透鏡 ,其目的是形成一定正像散的著(zhù)屏光點(diǎn)以抵消偏轉磁場(chǎng)產(chǎn)生的負像散。
