The rearview mirror has been transformed over the last decade into a high-tech electronic module. Compasses, temperature displays, remote keyless entry receivers, trip function displays, telematics capabilities, and microphones are all typical of the added value functions found in today’s mirrors.  Matthew Beecham looks back on some of the latest innovations

The future is bright for dim mirrors

“From our perspective,” said Enoch Jen, Senior Vice President, GENTEX Corp, “the trend for highly-feature mirrors shows no signs of easing up.  If you look back to 1987 when we introduced our first inside auto-dimming mirror, it incorporated the auto-dimming feature with no other electronic content.  Today, about half the average dollar content inside mirrors relates to the auto-dimming feature while the other half relates to one or more electronic features.”

Auto-dimming mirrors – or more correctly called electrochromic (EC) mirrors – reduce headlamp glare from following traffic. EC mirrors contain a gel that can darken when a small charge of electricity is applied. The electric charge is triggered when light sensors in the mirror detect too much light – typically from a glare – in the field of vision.

Since auto-dimming appeared as optional equipment on high-end vehicles, these mirrors have become either standard equipment or in option packages on vehicles in every market segment. In fact, the auto-dimming mirror market has shown phenomenal growth.  Jen added:  “About 15 years ago, we predicted inside auto-dimming mirrors could approach 50% of the market.  Today, we are more confident that is an achievable objective.  Last year, the penetration was about 18% on inside mirrors and 6% penetration on one or more outside mirrors.”

While auto-dimming rearview mirror technology has obvious benefits, they are still expensive.  Ficosa offers an alternative patented technology which costs half the price of current EC technology.  “We call it EAGLE (electrically actuated antiglare rearview mirror),” said Ramon Guixa, Rearview Mirror Systems Business Unit Director, Ficosa International.  “It is a prismatic mirror yet has the electronics of EC glass within it.  The electronics control the movement of the glass.”

Mirror, signal, display…

The prospects for LED turn signal mirrors look good, too.  “There is a lot of interest in adding turn signal and other features such as side blind zone indicators into the exterior mirrors,” said Jen.  “There is a lot of interest in North America as well as Europe.  There is also quite a bit of competition.  While we think that the pricing is going to continue to become more competitive, we can see a lot of market potential for those features also.”

Alf Liesener, Marketing Manager, Schefenacker Group Services GmbH, added:  “Those mirrors that include turn signals have already become a commodity product.  So we shall see a change in the market for turn signals, with certain automakers spending more money on the application in order to give their vehicle models a unique appearance.  Consequently, the light technology within those turn signals will also change.  We are working on a range of cost optimized solutions based on the latest lighting technology providing enhanced appearance.  Although Schefenacker has taken the decision to sell its lighting business, the turn signal competence will remain in the mirror business since this is one of our key strengths.”

The power-folding mirror market is also blossoming.  Although power-folding has long since featured on luxury cars, they are gradually being fitted to more and more minivans and SUVs. The unit value of outside mirrors is therefore relatively high, indeed they typically cost twice as much compared to the US or Europe. Power extending mirrors for towing caravans is another major area of research. Guixa told us: “The power-folding mirror market is growing, spelling out good news as it increases the value of the mirror and the costumer satisfaction.  We have our own system for folding the mirrors with different levels of new electronic functions.”

Across Western Europe, power-folding mirrors have long been popular in the luxury segment, not only helping to prevent damage from passing vehicles in congested streets and assist parking but also serving partly as a deterrent to vandals.   In fact, the exterior mirrors of some mid and high-end cars are typically packed with technology, including security lights, auto-dimming and heated glass and other electronic features.  Liesener added:  “Power-fold mirrors are a popular option in Europe today, for example, forming part of a comfort feature package.  We expect growth for power fold mirrors on smaller vehicles sold in certain emerging markets such as China.  In fact, we expect a 10% fitment rate of this application in this segment by 2010, up from about 4-5% this year.”
Ficosa recently launched its first multi-signal exterior rearview mirror.  The unit integrates a signaling module into the rearview mirror which works as a position lamp and turn signal using LEDs.  Guixa told us: “While exterior mirrors integrated with turn signals are already well established in the automotive marketplace, our innovation integrates the turn signals, daytime running lights and other features in one unit. The benefits include new styling features and cost reduction from product integration.” 

Reflecting on an industry

Although we can’t see a day when ‘mirror-less cars’ ever become a reality, cameras are being increasingly added to cars with the interior mirror being used as a video monitor.  For example, MagnaDonnelly has developed and introduced its so-called VideoMirror.  It aims to reduce the fear of hidden dangers and obstacles when parking.  It uses the company’s own technology to conceal a 3.5-inch colour display which receives its picture from a universal rear-mounted camera.  When reverse gear is selected, the video display automatically pops out from the side of the interior rearview mirror providing the driver an image of the area behind their vehicle.

In 2005, Schefenacker introduced the first camera-based blind spot monitoring system integrated in exterior mirrors (for the Volvo XC70) which incorporates a micro processor for image processing.  The system activates a hazard light as soon as other vehicles enter a warning zone. 

Guixa believes that rearview mirrors and cameras are complimentary technologies.  He said:  “By using cameras linked to the exterior mirrors, we can incorporate a range of driver assistance features. This is one of the routes we are pursuing with also integration of radar and lidar and infrared cameras technologies to become an ADAS [Advanced Driver Assistance System] technology supplier.  We expect to see more of these types of applications in the next generation of cars.  We are also developing fractal antennas, incorporating them into rearview mirrors. Such antenna can pick-up AM, FM, telephone, and GPS signals.  So this is the first step to connect the car to the outside world and as a second step we are also developing car-to-car communication modules to connect the car with other cars and the infrastructure.  We are moving from a company focused on plastics and electrical systems to one focused on electronics.” 

Tomorrow’s mirrors will feature fog sensing/signaling modules, gas sensing, occupant sensing, sign detection, pedestrian detection, etc.  In fact, about half of the mirrors Gentex Corp sells come with some sort of advanced electronic feature.  We can expect even more integrated technologies to come.  ”The main area that we are featuring our featured development efforts have to do with micro-electronic products, and this primarily related to CMOS image sensor technology,” concluded Jen.  “We feel that there is a lot of growth potential in features that we are currently offering or developing, such as obstacle detection, lane departure warning, occupant sensing and so on.”

See also: Global market review of automotive rearview mirrors – forecasts to 2013