MANUFACTURE OF SHADOW MASK FOR COLOR CATHODE-RAY TUBE

PURPOSE:To achieve uniform electron beam passing holes and improvement of accuracy by applying ultrasonic vibration to a coated etching resistant agent so as to eliminate bubbles existing in an interface between shadow mask material and the etching resistant agent. CONSTITUTION:One surface of a plate-like shadow mask material 13 is covered with a corrosion preventive film 17, and then, small holes are formed by etching the other surface having a small hole forming resist 16b. The resist 16b is peeled and removed. An etching resistant agent 18 is filled in and applied to the small holes, and is deposited on the surface where the resist is removed. Ultrasonic vibration is applied to the etching resistant agent so that bubbles contained in the etching resistant agent may be eliminated. Large recessed holes 9 communicated with the small holes 10 are formed by etching the other surface with a large hole forming resist 16a formed thereon. Consequently, the shadow mask material is completely covered with the etching resistant agent so that etching liquid is prevented from intruding into the shadow mask material, thus achieving a high quality.