Evolution of Car Lighting
Naveen Kumar
| 01-04-2024
· Auto Team
Over a hundred years ago, a car driver lost his way on New Year's Eve on a pitch-black night. Fortunately, a nearby farmer with a horse lamp guided him back home. This kerosene-burning horse lamp was called the "earliest car lamp."
The driver could hardly imagine that over a century later, car lamps have evolved beyond merely a luminous unit on automobiles, becoming symbols of the comprehensive performance of vehicle software and hardware.
Before delving into the innovations of modern car lamps, let's briefly review the developmental journey of automotive lighting.

Starting from Kerosene Lamps

The earliest car lamps used kerosene, a fuel unfamiliar to modern people. The brightness of vehicle-mounted kerosene lamps might not even match that of a few candles. Subsequently, an automotive engineer conceived the idea of adding a reflector behind the kerosene lamp, a precursor to focused lamps, yet the brightness remained limited.
This was followed by acetylene lamps, utilizing calcium carbide and water reactions to produce acetylene as fuel for illumination, typically generated by acetylene generators on automobiles. Acetylene lamps were somewhat akin to automatic headlights: as the vehicle moved, the agitation increased acetylene production, making the light brighter, but it dimmed when the car stopped due to reduced acetylene generation rate.
Next came incandescent and halogen lamps, marking the electrification stage of automotive lighting. Though Thomas Edison invented the incandescent lamp in 1879, carbon filament lamps couldn't withstand vibrations, and it was only with the advent of tungsten filament incandescent lamps that incandescent lighting indeed found application in automobiles.

2. The Significance of Halogen Car Lamps

Halogen lamps possess strong penetration capabilities, so some old-school off-road vehicles still use them.
From 1960 until now, halogen lamps have been the longest-used lamp technology. Following halogen lamps, we encountered xenon gas lamps, which utilize a booster to increase the vehicle's 12V voltage to 23,000V, stimulating xenon gas to produce light.
Xenon lamps offered higher brightness and consumed less power, thus having longer lifespans. However, their downside was apparent: poor penetration in adverse weather conditions. Following xenon lamps, LED lamps appeared. LED lamps, structured as light-emitting diodes, illuminate instantly without the delay of xenon lamps needing a few seconds to stabilize the light source.
LED Matrix lamps subsequently followed LED lamps. LED Matrix lamps, characterized by their internal multiple LEDs, allow individual adjustment of each lamp, achieving functions like dynamic swiveling, precise illumination, and control over the illumination range by grouping light sources.
With real-time image processing of front-view information captured by cameras, LED Matrix lamps can activate different driving modes during tailgating, encountering oncoming vehicles, or passing various traffic signs, such as rural illumination mode, highway illumination mode, dynamic curve illumination mode, and anti-glare high beam mode.

A Million Pixels: Used Solely for Illumination?

Current headlamp technology is advancing towards higher-resolution digital headlamps, with lamp pixels measured in the "millions."
High-resolution digital headlamps mainly rely on two technology directions: Digital Light Processing (DLP) and Micro LED. DLP technology achieves higher pixel density, reaching millions of pixels in headlamps.
DLP headlamps are LED combined with a Digital Micromirror Device (DMD). The technology's core of the DMD chip consists of millions of individually controllable micromirrors that reflect the light source, enabling finer partitioned illumination and high-definition projection functionality through visual chips.
With each pixel comprising 1.3 million micro mirrors, the entire headlamp system boasts 2.6 million pixels, facilitating precise, intelligent illumination and an effortless direct projection of a video movie.
Unlike digital headlamp technology, intelligent electric vehicles today typically come equipped with a set of digital signal lamp systems, termed Intelligent Signal Display (ISD) in the HiPhi X by the brand. Unlike traditional lamps used for illumination, these digital signal lamp systems, composed of thousands of LED light sources, undertake various intelligent scene functions, forming a complete intelligent lamp interaction system alongside digital headlamps.
Recently, a particular brand has gained significant attention for its matrix light source tail lamps with intelligent interaction functions, capable of directly displaying heart-shaped patterns during wedding car scenes, showcasing the intriguing evolutionary direction of lamp technology. Besides DLP technology, digital headlamps with higher pixel counts also adopt Micro LED technology.
From LED to Matrix LED, and now to the era of higher pixel count digital headlamps, it's evident that the Adaptive Driving Beam (ADB) function, facilitating efficient illumination, is merely the beginning of lamp intelligence. With the rapid iteration of technology in the era of new energy, today's lamps are undoubtedly sprinting down the road of intelligence.