Abstract: A method for the preparation of an illuminance-correcting light transmitting filter employed in an exposure device adapted for the preparation of the phosphor screen of the color cathode ray tube. The laser light modulated with a light modulator is radiated to the surface of the filter base plate on which a thin layer of the recording material is previously formed. A pattern of through-holes of variable size or density is formed as the thin layer is vaporized so that the light transmitting filter may be prepared with high accuracy and in a shorter time. The laser light is modified with the light modulator, and the filter base plate is securely mounted to a movable stage, the movement of which in the X- and Y- directions is controlled under the commands of a computer unit.

Abstract: A method for manufacturing rotary ball display devices wherein a plurality of such balls are provided with a coating of a color different from the remainder of the ball, the ball members are coated with a thin coating insoluble in the settling medium into which they are introduced, so that upon settling into a low viscosity liquid, they form a uniform layer. A high molecular weight hardenable coating material which is soluble in the low viscosity liquid is then poured onto the coated ball members to cover the layer. Then, the low viscosity liquid is removed and the hardenable coating material is caused to harden. The thin coating is then dissolved away from portions of the ball members to leave cavity portions thereabout into which a high resistivity liquid is introduced. The resulting ball members have a refractive index on the colored layer which is substantially the same as the refractive index of the high resistivity liquid contained in the cavities.