Why You Shouldn't Buy a Cheap Pico Projector? The Technical Fact Check

With small form factors, convenient portability, and effortless Wi-Fi and HDMI connections, portable projectors have become among the most sought after products for consumer electronics enthusiasts. Options for consumers such as built-in battery models and LED projectors have also grown to a full array of choices for any setting. And because they work so well wherever people live, play, and work, coupled with advancements in streaming video, these simple, portable, and wireless projectors that project onto a large screen anytime, anywhere are popping up all over the place.

Because most portable projector brands are newcomers to the field, they often rely on overloading features onto existing designs and cutthroat pricing just to survive, turning the portable market into a field riddled with guerilla warfare that causes unrealistic specs and unsustainable prices. How can the average consumer identify marketing ploys, avoid buying duds, and select the right portable projector? BenQ is here to answer those questions. 

• What is the technology behind portable projectors? How do portable projectors work?
• How bad are cheap LCD portable projectors?
• What are the three key points to consider when evaluating a portable projector?
• What are some tips for buying the best portable projector?

Currently, the projector market is split between Digital Light Processing (DLP) and Liquid Crystal Display (LCD) models. To increase competitiveness, some brands recently developed cost-effective pico projectors that utilize a single-panel LCD combined with simpler lenses and optical parts. These smartphone-type LCDs are lower cost than DLP Digital Micro-Mirror Devices (DMD), so most companies do not fully consider the effects on image quality when choosing this type of technology for their portable projectors.  

The principle behind single-panel LCD projectors is very similar to old fashioned slide projectors used in schools. It uses a single semitransparent liquid crystal screen to display the image, through which the light source shines to project images onto a mirror. The image is then reflected through a lens to enlarge the projection, resulting in viewable content.

The problem with this system is the inadequate transparency of liquid crystal screens, with an average light transmission rate of 4% to 6% or at best only 10% limiting their brightness. The only way to increase image brightness is to boost the light source. But since these smartphone LCDs are sensitive to heat, an increase in light source brightness can damage the liquid crystal molecules. In summary, single-panel LCD projectors have low light energy conversion rates, and technology has not found a way to produce high brightness on these types of projectors.

How do you evaluate a functional and practical portable projector?

Consider these three key points:

1.Brightness

2.Image quality

3.Portability

As explained above, single-panel LCD projectors are limited due to brightness and temperature factors, with current single-panel LCD projectors producing real brightness levels of only 200 to 300 lumens at best. Yet single-panel LCD projectors with advertised brightness of 2,000 to 3,000 lumens can be found everywhere in the marketplace. In reality, these numbers are hugely inflated. Because online shopping is so prevalent, consumers are unable to test the actual performance of a projector. This can cause them to be enticed by inflated numbers and bargain prices only to find out that they have been fooled after receiving a worse-than-advertised product.

Obviously, the most essential parts that determine a projector’s image quality are the light source, imaging elements, and lens-related optical components. But in order to keep prices low, single-panel LCD projectors use lower-cost smartphone display panels as imaging elements and simplified optical mechanics, which produce uneven lighting. This in turn causes the projected image to be clear in the centre but hazy towards the edges, which is the unavoidable consequence of using sub-standard technology.

Portability is another key selling point of portable projectors, and volume/size is an important purchasing consideration for consumers. But with single-panel LCD projectors, any decrease in size results in the problem of bottlenecking. This problem arises from the use by cheap portable projectors of smartphone LCDs as the main imaging component, because the LCD cannot achieve higher resolutions such as 720P if it is too small. With most smartphone LCD panels sized 5 to 6 inches, compared to 0.3-inch DMDs for DLP pico projectors, the difference in size can be up to ten or twenty fold. Additionally, for the light source to effectively cover the entire image when it shines on the LCD panel, all internal projector mechanics, including the lens and mirror, have to adjust according to panel size. As a result, single-panel LCD portable projectors are unable to achieve the portability of DLP portable projectors.

The image shows a BenQ GV1 with 180lm brightness on the left compared to a single-panel LCD projector with a measured brightness level of 90lm. Not only is the DLP-based GV1 significantly smaller, its brightness is also double that of the LCD projector.

This article provides consumers a better understanding of portable projectors, helps recognize marketing tricks and misleading specs, and shows how to avoid being tricked by certain brands. Knowing the tricks of the trade described above, your best choice for the most effective projector with the best imaging technology is a DLP portable projector.