How LCD Projectors Work ?

LCD projectors have been around since the 1980s, and use the same liquid crystal displays that create the images in watches and other electronic devices. Specifically, most LCD projectors use 3 LCD technology, a patented system that combines three liquid crystal displays. An image is created in a multistep process, which begins with the light source providing a beam of white light. The white light is passed to three mirrors (called dichroic mirrors) that are specially shaped to reflect only a certain wavelength of light. In this case, the mirrors reflect red, blue, and green wavelengths. Each beam of colored light is then fed to an LCD panel, which receives an electrical signal that tells it how to arrange the pixels in the display to create the image. All three LCD panels create the same image, but they have different hues because of the colored light passing through the panel. The images then combine in a prism, creating a single image with up to 16.7 million colors that is passed through the lens and projected onto the screen.

You know the feeling, the projector lamp image is fading so you log into a replacement lamp website (like and start feeling dizzy when you see the price. The ‘first time buyer’ phoning for a lamp is obvious as they ask me to repeat the price. No doubt comparing it with the last time they replaced the bathroom bulb and hoping. Although lamp prices are falling it will be long time before lamps reach that price and the double dip recession is not to blame.

The manufacturers(Epson, Hitachi, Sony) have always claimed that the housing and intricate components for a projector bulb mean the price is so much higher than a standard bulb and hence not only the price but the use of ‘lamp’ rather than ‘bulb’ terminology to imply it’s far greater complexity! We still sell far more original lamps than copies as consumers compare ‘tried and trusted’ models against copies. The ‘diamond lamp’ option is becoming more popular as customers appreciate that this copy is actually the same bulb but with housing made in Britain. But the bottom line is that they are expensive.

But then you also have to remember that despite manufacturers’ claims a new bulb rarely takes the projector back to its original brightness. In fact the more replacements you make the more disappointed the end result. Even if the image is once again bright the projector gets older and the chances of other components failing increase.

For what it’s worth, I would plan on replacing the bulb three or four times if you use the projector a lot before investing in a new model. If your use is infrequent then the advantage of an upgraded modern model might mean replacing it more frequently.