Wednesday, November 25, 2015

The LED vs. OLED Issue

Two Escort radar detectors during testing. Passport Max2 (left) uses OLEDs. Redline uses LEDs. (Both are temporarily powered-up and running in Highway mode for this photo. Max2 display brightness is set to maximum; Redline's is 75%.)

If the display on some radar detectors looks a bit different, it's no illusion. You're looking at OLEDs (Organic Light Emitting Diodes) instead of LEDs.

OLED technology uses an organic layer to create a digital display, much like a miniature flat-screen monitor. Onto this can be displayed alphanumeric characters, images or both.

An LED (Light Emitting Diode) works like a light bulb: apply electrical current and it glows. Rows containing hundreds of LEDs are used to create alphanumeric characters—Ka Band or 9, for example.

The LED is cheap and reliable, but it lacks the versatility of an OLED. The latter is more expensive, which is why manufacturers tend to use it on higher-end models.

Some marketing people seem enamored of OLEDs for a radar detector display. Maybe they subscribe to the adage "a picture is worth a thousand words". Regardless, an OLED display does have two marketing advantages over its elder LED brother—it looks sexier and it can display images.

Cobra Electronics was the first to recognize that an OLED display can make a detector stand out from the pack. When I tested the XRS-9970G a few years ago I charitably opined that the display was gorgeous.  At 1.5 inches square, it was also huge.

Appearance aside, driving with the Cobra was a chore. Staring at this miniature TV dead-center on the windshield was an enormous distraction. It was worse at night.

No doubt Cobra was aware of the annoyance factor; the display automatically went dark after a period of inactivity. A pulsing yellow dot served as confirmation that it was still receiving power. But no other information was available and during the day, the pale yellow dot was tough to see.  To check on the Cobra's vital signs, the driver first had to press a button to wake it up, a nuisance.

To the human eye, these two technologies behave differently. When an LED lights up, it's easy to spot, even with peripheral vision. An OLED doesn't have the same punch: it's not nearly as bright and it merely overlays a foreground color over a background. Even a white font over a black background seems relatively muted.  

The OLED's lower contrast is most noticeable under tough daytime lighting conditions. Here in the desert southwest, a detector hanging from the windshield is usually backlit by intense sunlight.

The OLED doesn't fare well in these conditions. When testing some detectors with OLED displays, I find it necessary to remove my sunglasses, pull the detector from its mount and hold it at eye level to read it.

On its early model Cobra somewhat compensated for an OLED's lower contrast by using XXL-size fonts and images to increase readability. For its blue OLED display, Whistler resisted the impulse to decorate it with images but likewise opted to use big, alphanumeric characters.

Escort and Beltronics (BEL) took a different approach. Like the Whistler, default font color is blue, but users can choose amber, red or green instead. Altering colors affects only the text; nothing else is changed.

Although the Escort and Whistler displays are nearly identical in size, the Whistler's is much easier to read, particularly on sunny days. After some measuring with calipers it became clear why.

One big factor is how the real estate is used. On the CR90, for example, Whistler shows mode, status and alerts using the full width of the screen. In contrast, the Escort uses about 60 percent of its screen to display the same data. The other 40 percent is reserved for other information. On the Passport X70, for example, vehicle voltage is displayed. On GPS-enabled models this spot may show road speed, information arguably more useful than volts.

Shoehorning more data into less space entails some compromises. Whistler's alphanumeric characters are 65% larger than Escort's, for example. And there's significantly more space (kerning) between them.

In some display modes the Escort's font size shrinks even more. For instance, the Spec mode option shows a radar gun's numeric frequency.  To accommodate the extra data, font size is reduced a further 30 percent, making the display even tougher to read.  

If you can read a newspaper from across the room, none of this matters. For others, the LED vs. OLED issue has significance because a radar detector is an information-delivery device. One that's better able to convey that information can help the driver dodge a speeding ticket.