Projectors have been around for more than 40 years. The earliest of them were the Advent and Kloss models. Sharp revolutionized the projectors with digital imaging which allowed for a high intensity bulb to be imaged through an LCD panel and live in a much smaller box.
LCD projectors dominated the industry, until about the mid 90’s when DLP built by Texas Instruments came onto the market. Many manufacturers went with the DLP system and still today it is the most widely used imaging system. Never buy a projector by specs; the picture is what counts.