automotive glazing glazing perspectives at the frankfurt motor...

Glass-Technology International 2/1998103

Website: http://www.glassonline.com

Automotive glazing

Glazing perspectivesat the Frankfurt

Motor Show 1997(second part)

The second part of the report on the main demandson automotive glazing from designers and car makers

at the Frankfurt Motor Show 1997 assesses the consequencesof increasingly complex shape and all round visibility

for sunroofs and transparent roofs. The author also reportson glazing solutions for mirrors, plastic lenses and

navigation display systems. The first part, publishedin issue 1/98, looked at the implications of the above trends

for rear and side windows and windscreens.The consequent safety and comfort requirements

for IR absorbing glass, IR reflecting glass, as well as strongerimpact and break resistance, were also examined,together with the implications of the increased use

of ergonomic colour inside the car.

Giovanni Manfré*

MG CONSULT

104

Glass-Technology International 2/1998Website: http://www.glassonline.com

I ntroductionAs shown in thefirst part of the report,the need, apparent in all marketsegments, to satisfy the desire forpersonalization of the cars, aswell as for a feeling of driving inthe open air, were a strongleitmotif of the Frankfurt MotorShow 1997. One of the maincontributions to this multi-functional need is certainly thetransparent roof, which has nearlyreached industrial production inthe different niches, while thesunroof has reached massproduction in all segments of car production,even the most popular. This second part of thereport will try to describe the result of co-design among designers, car and sunroofmanufacturers and glassmakers.

Transparent roofsThe whole roof, conceived also as a sunroof,

might be realized in several ways, as seen inthose exhibited at the Frankfurt Motor Show1997.

FixedWith this solution, the roof is composed of

one monolithic pane of glass, as in the newSL320 (see Figure 1) by Mercedes. It is like apavillon which wraps the windscreen and rearwindow in different ways, though the bestexample is the detailed glass to glass joints atthe front and back in the SL320. Otherexamples of these kinds of joints are on theSmart City car at the front (see Figure 2a) andback (see Figure 2b).

In three partsIn this case the back of the roof is fixed, the

front tilts as a wind panel, while the middlepanel is movable, underlying the fixed backpanel when open. This is already the classicsolution for the Porsche Targa, where the threeparts are closed. The glass to glass joints areshown in Figure 3.

PavillonThis type of roof is composed of several

moving lamella panels and can be consideredthe most advanced solution at present. It is avery innovative concept for glassmakers, on alevel with the opaque lamellae solution in theMercedes Class A. The best example of thissolution is that of the five louvered glass panelson the MC2 concept car by Ford. The idea of a

Fig. 1Monolithicroof of theMercedes

SL320

Fig. 2a & bGlass to glass jointson the Smart City

Fig. 2b

106




roof made up of lamellae is based on theMultivent prototype, developed by Webasto asa new roof system for the Mercedes Class A(see Figure 4a) in five opaque twin-shell steellamellae. The system seems to satisfy thefollowing points:• greatly enhanced ratio of roof area to roof

opening;

• low noise and draught levels despite largeopening;

• ventilator setting which can also be used inpoor weather;

• no rattling or vibration with the roof open;• security against break-in at least as good as

existing sunroofs made of steel (as in theClass A) or glass (as in the MC2);

• electrical operation.When the roof is opened (see Figure 4b), the

deflector props up first, followed by the otherlamellae, which slide out parallel to the roofskin, moving along the same lines as thefolding roof one after the other right to the rear(see Figure 4c). In the ventilator setting, thedeflector is fully open, while the fifth lamella is

Fig. 3a, b & cThree-part roof of the Porsche Targa

Fig. 4a, b & cOpening opaque roof of the Mercedes Class A

Fig. 3a

Fig. 3b

Fig. 3c

Fig. 4a

Fig. 4b

Fig. 4c

108


only slightly ajar. Figure 5, showing theinternal frame, gives an indication of theassembly production of the flushing roof. Inorder to understand the real evolution of thelamella concept, it is interesting to note theprevious design of the roof, with a single,flexible, opaque fabric, used for example in theFord Fiesta (see Figure 6), or in many cabrioletcars.

In two partsAn example of a two-part transparent roof is

the Technas SUV by Mitsubishi.This kind of roof is composed of a glass wind

deflector which can prop up, together with the

fixed or moving large part. The fixed part canbe in glass, as in a particular Smart model,which has a wind deflector, a fixed glass panelin the middle and a fixed rear panel also inglass.

Among other two-part roofs we can alsomention the Megane Scenic (designed byInalfa), with the wind flap in Venus glass andthe second part (see Figure 7) in a flexibleopaque fabric. Two examples, both byWebasto, and which belong to the category ofsunroof equipment, are the three glass panelson the Peugeot 806 and the two twin movingglass panels in the Megane family by Renault.

SunroofsThe variety of sunroofs, fixed-tilting, in one,

two or three parts, with or without shadingdevice and electrically sliding underneath, wasone of the leitmotifs of the Frankfurt MotorShow 1997. This result can be taken as the firstspin-off of the increasing interest of designersin the last five years.

Flushing encapsulationThe flushing encapsulation achieved with

PU-RIM technology now gives full integrationbetween the sunroof and the body roof. Thebest examples shown at Frankfurt 1997 were:• the Opel Corsa Advantage (see Figure 8);• the recent VW Passat;

Fig. 5Internalframe of theClass A

Fig. 6Opaque roof

of the FordFiesta with

folding fabric

Fig. 7The Megane Scenic by Renault

Fig. 8The Opel Corsa Advantagewith flushing sunroof

Fig. 5 Fig. 6

Fig. 7

Fig. 8

110


• the new VW Golf with OM flushingsunroof;

• the Mercedes Coupé Sport and E55 AMGAvant-garde.Two examples, the sunroof on the Mercedes

E320 and on the Nissan Micra (see Figure 9),illustrate the difference between the flushingencapsulated sunroof mentioned above andprevious, non-flushing encapsulated panels.

Rockwell and Webasto also seem to haveproduced flushing encapsulated technology.

Moving devicesCompetition on the moving device on

sunroofs seems to be between sliding systemscomposed of either one or two parts, as in theMercedes S500 (see Figure 10), or in theMercedes Pullman (see Figure 11). In evolutionwith the sliding device, there are two newconcepts of a tilting or winding up system. Thelatter has already been developed by Webasto,as well as a new concept (see Figure 12),designed by students of the Art Center Collegeof Design in Pasadena, USA, an overall winnerin a competition organized by Webasto forideas on sunroof designs for MPV and SUVvehicles.

The concept of a tilting sunroof waspresented by Inalfa. Another interesting tiltingdevice for large sunroofs has been produced bythe VW Karman Ghia designer in a MPV OpelView II vehicle.

Solar control and privacy glassesAs seen in the first part of this report, there is

increasing interest among car and sunroof

Fig. 9The Nissan Micra - an example of non-flushing sunroofs

Fig. 10Sunroof of the Mercedes S500

Fig. 11Sunroof of the Mercedes Pullman

Fig. 12A new concept for tilting sunroofs

Fig. 9 Fig. 10

Fig. 11

Fig. 12



makers in using more solar control or privacyglasses in the sunroof. Evidence of this isSaint-Gobain’s new Venus privacy glass, themoving part of the transparent roof on thePorsche Targa, shown at the Webasto stand,and the Inalfa sunroofs on the F1000, FarmontF1000 Plus and F1000 Compact, as well as theVolvo C70 (see Figure 13).

Increased transparent surfaceThe increased transparent surface is well

represented by the Land Rover Freelander. TheStation Wagon has one sunroof and the XEHardback model has two transparent glasspanels in the front area (see Figure 14).

Photo-voltaic sunroofsRockwell and Webasto have presented a

feasible industrial solution for a photo-voltaicsunroof which decreases the internal airtemperature of a car in full sun by nearly 25°C.

MirrorsNo real innovation seems to have been

developed at present in this area, except for theAISIN deflector, with retractable rear-undermirrors. However, electrochromatic (EC) fluidanti-glare technology by Gentex has beenconsolidated, with a small increase of internalEC mirrors. In addition, there was a significantgrowth of aspherical mirrors, not only inGermany, but also in France and Japan. This isin line with the increase of all round visibility,for which other approaches were also noted.

No mention was made either of micro-camera or prismatic technologies. However,interestingly, a marked trend was noted amongdesigners to situate the external mirror in amore convenient position, in order to reducethe dead angle both in width and heightwithout the use of aspherical mirrors.

Anti-glareEC internal mirrors are still confined to the

upper class level of cars, while the onlyexternal EC mirror mentioned is by BMW (seeFigure 15). As well as reducing glare, theBMW external mirror is equipped with an

Fig. 14The Landrover XE Hardback sunroof with two panels

Fig. 15External EC mirrors exhibited by BMW

Fig. 13

Fig. 14

Fig. 15

Fig. 13The Inalfa

sunroof onthe Volvo

C70

112


automatic dip function, which lowers thereflecting surface as soon as the driver shifts toreverse, providing a good view of the curbwhen backing into a parking space, forinstance.

Aspherical mirrorsAspherical mirrors seem to be increasing

their penetration in all parts of the world. Infact, Frankfurt 1997 showed many cars inwhich aspherical mirrors have been adopted forfinal production. In previous reports, greatinterest was noticed especially among Germancar makers. Now, however, aspherical mirrorsare part of the equipment for car makers inFrance and Japan, even in mass produced cars.Citroen’s choice for the mass produced carXsara can be considered the typical asphericalmirror in France, while in Japan it isMitsubishi’s choice in the mass producedCarisma car. Mercedes has also adopted theaspherical mirror in the Smart City car (seeFigure 16), demonstrating its necessity in allcar segments.

However, car makers also commented on thepresent limitations of aspherical mirrors. Oneof these is the distortion of the reflecting imagein the curved part of the mirror. They also givean incorrect perception of the rear distance ofapproaching cars, especially ones appearing inthe dead lateral zone. Aspherical mirrors alsoneed to be larger than normal mirrors. In fact on

the Carisma car, the increase of the dead angleof an aspherical mirror - without increasing thesize of the mirror - is quite small, only 5.3°. Inmost cases, when the aspherical mirror isenlarged to the necessary size it does notintegrate well, especially on the small cars (seeFigures 16 and 17), or even on middle size cars.

Innovative conceptsThe only really innovative concept, which is

perhaps a sign that the micro-camera isnot yet ready for mass production, is theAISIN prototype “Rear deflector with foldingmirror.”

The rear mirror is placed on the back bumperand operates by an electrical mechanism whichretracts and opens the deflector. When thedeflector is opened, the mirror view is quitelarge both in height and breadth. When thedeflector is closed, the rear shape of the carlooks aerodynamically simple and pleasing tothe eye.

Designers’ trends for mirror positionsThe main trends were for increasing the rear

visibility of mirrors and achieving betterintegration of external mirror supports. Hencethe external mirror is joined with the externalbody, rather than the lateral window. This is inorder to improve lateral and lower rear vision,as well as to better integrate the mirror supportwith the body shape and colour. Typicalexamples are the solution on the concept car

Fig. 16Asphericalmirror of theSmart Citycar byMercedes

Fig. 17Image

distortion inthe Smart

City’saspherical

mirror

114


Audi Al2 (see Figure 18) and the BMW car.

Even the innovative Unicar, designed by IKA,and the Technas, by Mitsubishi, show anintegrated solution for the external mirror.

Internal mirrors have also begun to beconceived as more integrated with the internalbody, using joints, as opposed to the presentsolution of glue on the inside of the glasswindscreen. A very representative example isthe Smart City car, where the well designedsupport for the internal mirror is attached to theinside of the car roof. The mirror producersMetagal (Brazil) and Ficosa (Spain) showedthey are ready to satisfy the latest trends ofdesigners.

Mirror producers’ standsThe presence of mirror producers was

scattered among the stands of assemblers suchas Marelli (AISIN) and a number of others.However, a larger number of mirror producershad their own stands at Frankfurt 1997compared to the previous edition of the show.The most noticeable stands of verticalized rearmirror manufacturers were those of Metagal

and Ficosa. Metagal can be considered one ofthe most international verticalized mirrormanufacturing companies, for its wide range ofmirrors (see Figure 19), as well as the veryspecial shape, size, integrated plastic support,electrical and electronic devices. Ficosa alsoshowed a wide range of car mirrors, as well asthe most recent advancement in asphericalreflecting surfaces (see Figure 20) and a fairlycomplex and integrated plastic support. Anti-glare mirrors were presented at Metagal’s standbut not at Ficosa’s. The latter intends topenetrate the South American and Far Eastern(China and Malaysia) markets much moreintensively.

Navigation display systemsAs mentioned in the first part of this report,

the trend for greater colour variety of the trimand dashboard has certainly made it necessaryto reduce internal reflection in the glazing ofinterior surfaces, especially for the monitor ofthe navigation system map. Navigation systems

Fig. 18External

mirror on theAudi Al2

concept car

Fig. 19Metagal mirrors with sophisticatedplastic support

Fig. 20Automotive mirror products by Ficosa

Fig. 19

Fig. 20



are now being mass produced for a wide rangeof cars. The ergonomic concept of the suitableposition for the map display is changing fromthe lateral position, beside the driver, to thefront, just over the steering wheel area or on thewindscreen, as an HUD using differenttechnologies, such as a hologram or selectivereflection. Frankfurt 1997 did not show anyHUDs on the windscreen. However, it did showa more ergonomic and safer position of the mapdisplay in front of the steering wheel area,where it is almost integrated onto thedashboard. An example of this is the new mass-produced Golf (VW) and the Trail Runnersports car by Nissan (see Figure 21). However,in my opinion, the challenge for the glassmakeris undoubtedly to find a solution for the massproduction of HUD on the windscreen, asannounced by Mitsubishi for the Technasmodel and by Nissan for the Trail Runnermodel.

Another important feature related tonavigation systems, which is already inproduction in some cases, is the glass aerial.There is a preference to insert this in the rearwindow, with implications for aesthetics andfor multi-point terminal technology. Animportant example is a future solution by Fordfor a rear window with five aerials, presentedat the Ford stand at Frankfurt 1997. Othertechnology is also being developed forMercedes cars. It includes, for instance, theDynamic APS, for the transfer of trafficinformation, the Tele AID, for linking toemergency call centres and the Linguatronic

telephonic voice operation system. The maindetailed presentations of navigation systems atthe show were:• the AISIN display or voice system, adopted

mainly by Toyota (AISIN produced about160,000 navigation display systems in1996);

• the Delco system, adopted mainly by BMW;• the Blaupunkt (Bosch) system, adopted

mainly by Mercedes;• the Alpine system, adopted mainly by GM,

Chrysler, Volvo, Renault and Fiat;• the Nippondenso system, adopted mainly by

Toyota and Honda;• the Marelli system, adopted mainly by Fiat,

Alfa, Lancia and Peugeot;• the Siemens system, operating mainly with

GM and Ford.

Plastic lensesThe evolution of transparent plastic on

headlight lenses shows two essential trends. Onone hand, there has been a sharp increase ofplastic lenses in nearly all innovative carswhere the concept of complex shape involvesgreater integration of the lenses with the frontbody of the car. This has led to three mainshapes of plastic lenses:• the drop shape, as in the innovative Class A

Mercedes (see Figure 22) and the ToyotaFuncar;

Fig. 21HUD in theNissan TrailRunner

Fig. 22Drop shape

lenses of theMercedes

Class A

116


• the round shape, first brought in at Frankfurt1995 by Mercedes and now applied inseveral high-level and sports cars such as thePorsche 911 Turbo (see Figure 23) and nowthe 911 Carrera, where the single round lensis split into three integrated lenses whichblend very well with the front body;

• the rectangular shape, typified by thelenses in Ford cars, now moreintegrated with the front body by onevery thin lens and a second lens in thelower front.On the other hand, the second trend is

for versatility with the new lightingtechnology. Important innovations inthis field are modifying the shape andintegration of plastic headlight lenses,which have proved to be more versatilethan glass. One example of lenses

Information Service n. 13See coupon on the last page

adapted to the new high-tech conceptof lighting is the Audi Al2, where asingle light source (see Figure 24)positioned at one side projects a rayof light through a system ofpreliminary lenses and high guides tofour head lenses. The new design isshorter and lighter and illuminatesthe road surface more effectively.The rear lights are also designed toilluminate the area surrounding thevehicle reliably, with improved allround visibility during night driving.The new lighting technology couldalso have consequences for glazing.The evolution of transparent plasticlenses should always be considered aprecursor of what could happen iftransparent plastic should replaceglazing in the automotive field.

Fig. 23Round plasticlenses ofthe Porsche911 Turbo

Fig. 24The new concept of lighting inthe Audi Al2

*ConsultantMG Consult - Italy

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