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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
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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
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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
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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
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• 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
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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
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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
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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
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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
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• 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