I think I've just about got my head around what '3LCD' means in projectors – three LCD imaging panels, one for each of the primary colours. Makes perfect sense, so what's 4LCD all about? Has someone come up with a new primary colour, maybe?In fact it's a bit of technology just announced by Sanyo, and featured in a new projector designed for the presentation market. And here's one she made earlier...If normal projector technology trends are anything to go by, and given the fact that 4LCD sounds much more impressive than 3LCD, chances are it'll find its way down the range into home-use projectors in pretty short order. At the moment, though, it's designed as a means of boosting the quality of really big images, or for projection in environments with greater ambient light.Quick science bit. 3LCD uses a trio of LCD panels, arranged in an open-sided 'box' around a prism, with the projector lens on the open side of the 'box'. Light from the projector lamp is fed to the three prisms by a series of dichroic – in rough terms, half-silvered – mirrors.Each panel delivers one colour - red, green or blue - and the prism combines all of these into the image you see on screen.With me so far? Good – except it seems that as brightness increases, colours become washed out, meaning that ultra-bright projectors, such as you might use in situations with high ambient levels, for really big pictures or long throw distances, lose contrast and colour definition.Hence 4LCD, which places an extra colour control device into the image engine, giving automatic control of the amount of yellow light in the system. Like this, in fact...The result is a projector able to deliver 7000 lumen brightness and 2200:1 contrast ratio, and clearly the shape of things to come, according to a company spokesman: "This is just the first of many projectors we will release featuring our new 4LCD Engine."The increased luminosity and contrast ratio coupled with the dramatically improved color accuracy of this new design is going to revolutionize the capabilities of LCD projector solutions."Only one downside – the first model, due on the Japanese market this autumn, will cost you 1.89m yen, or about £9000. But that's just for starters – trickledown effect, anyone...?