A method and apparatus for a pump control system. The projection display separates a unit of time configuring the image data into an effective light time when the light modulating device can express the light as an image on the screen and an ineffective light time when the light modulating device cannot express the light as an image on the screen. The dielectric layer is formed on the metal electrodes by firing a glass material. The first and the second reference bit line generators respectively detect voltage level variations of the first and last bit lines according to the pre-word line signal, so as to generate a first and a second cut-back signals. The window may be formed from a transparent material through which an end of the tube can be seen when the tube is correctly located within the connector.