VALEO EXHIBIT 1032
`Valeo v. Magna
`IPR2015-____
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`VALEO EX. 1032_001
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_002
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_003
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_004
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_005
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_006
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_007
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`942
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`J. F. NOLAN
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`ELECTRODE
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`TRANSPARENT
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`ELECTRODE
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`INSULATING LAYER
` -Q --—-ACTIVE LAYER
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`GLASS
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`SUBSTRATE
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`Fig. 6 - A-c thin film electroluminescent display
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`(> 105 h) can be obtained at a brightness (> 1000 foot-
`lamberts) which is large compared to other displays. Al-
`though incandescent displays have been around for a long
`time, they are still the subject of some research activity.
`Work has recently been reported on an investigation of
`an incandescent matrix display fabricated using thin film
`techniques (23, 24).
`
`ELECTROLUMINESCENT
`
`Electroluminescence is the generation of light on the
`application of an electric field to certain solid materials.
`Materials which exhibit this property are called electro-
`luminescent phosphors; perhaps the best known example
`is zinc sulfide activated with manganese. Electrolumines-
`cent displays use the phenomenon of field effect electro-
`luminescence, as distinguished from injection electrolumi-
`nescence which is used in light emitting diodes. The use
`of electroluminescence to display information is a subject
`that has received attention in research laboratories for
`
`many years. A substantial research effort was undertaken
`at many laboratories in the 1950s in the hope of develop-
`ing practical electronic displays for many applications in-
`cluding television. The early promise was not realized,
`and the amount of effort dwindled. One of the main
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`problems with these early devices was the great difficulty
`that was encountered in obtaining adequate brightness
`and operating life at the same time. Some recent work
`has been reported (25, 26) which shows significant prog-
`ress in brightness and life, and interest in electrolumines-
`cent displays is reviving.
`A number of different materials have been found which
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`exhibit electroluminescence; typically they are II-VI com-
`pounds. Most electroluminescent materials require acti-
`vators; that is, impurities in the host material which give
`rise to luminescent centers that are responsible for the
`characteristics of the emitted radiation. The details of the
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`physical processes which lead to electroluminescence are
`quite complex; a number of explanations have been pro-
`posed to account for observed effects in different mate-
`rials. In one model which has been applied to zinc sulfide
`systems, electrons and holes are generated at localized
`high field regions. The holes become trapped in relatively
`deep luminescent centers (~1 eV above the valence
`band). The electron traps are much shallower, and the
`relatively mobile electrons can move under the influence
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`of the applied electric field and recombine with the holes
`at the luminescent centers giving rise to recombination
`radiation which constitutes the light emitted by the mate-
`rial. Other models have been proposed to explain the
`large variety of effects that have been observed in electro-
`luminescent materials. A great deal of work has been
`done on the theoretical and practical aspects of electro-
`luminescent devices, and comprehensive reviews are
`available (6, 27-29).
`Electroluminescent displays may be d-c or a-c, and the
`electroluminescent material may be incorporated into the
`device in the form of powders or thin films. Devices
`which use vacuum deposited thin films of EL materials
`are sometimes referred to as light emitting films (LEF).
`Fig. 6 shows a schematic representation of an a-c thin
`film electroluminescent panel. Starting with a glass sub-
`strate with a transparent conducting electrode a thin film
`(~ 2000 A) of insulating material is vacuum evaporated
`over the electrode. YZO, has been used for this film.
`Over this insulating film the layer of active electrolumi-
`nescent material is evaporated (typically 5000 A of ZnS
`doped with Mn). This if followed by a second insulating
`layer and finally by a metallic conductor which acts as
`the other electrode. When an a-c potential is applied to
`the electrodes, the EL material emits light which is viewed
`through the glass substrate. A brightness of about 1000
`foot-lamberts has been obtained with a voltage of about
`300 V.
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`Segmented numeric displays have been made using a-c
`thin film EL which incorporate a black absorbing layer
`over the entire back electrode surface; that is, the back
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`insulating layer in Fig. 6 is made opaque instead of trans-
`parent (27, 30). This gives the device an exceptionally
`high contrast ratio, and the display preserves a good ap-
`pearance in high ambient light levels even with a bright-
`ness of less than 10 foot-lamberts in the active area.
`
`Experimental work is continuing on electroluminescent
`matrix displays (31). One device incorporates the ad-
`dressing circuit, including thin film transistors, directly
`on the display panel (32).
`Electroluminescent displays operate at a relatively high
`voltage (200-600 V). They have fast response times and
`can be made rugged. Laboratory devices have been made
`recently which have operated for more than 10,000 h at a
`brightness of 1000 foot-lamberts. Most devices use
`ZnS:Mn and emit in the yellow part of the spectrum.
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`VALEO EX. 1032_008
`VALEO EX. 1032_008
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`SURVEY OF ELECTRONIC DISPLAYS
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`Some work was recently reported on a red-emitting EL
`panel using ZnS:TbF,, Mn as the active material (33).
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`LIQUID CRYSTAL
`
`Liquid crystals are organic fluids composed of long,
`rod-like molecules. Within a limited temperature range,
`liquid crystal materials have the flow properties of con-
`ventional fluids but also have some of the long-range
`ordering characteristics of crystalline solids. Liquid crys-
`tal materials have been known for over 80 years, but it
`has been only in the last ten years that they have been
`investigated as a display medium. A great deal has been
`learned about liquid crystals, and this knowledge has been
`summarized in reviews of liquid crystal materials and de-
`vices (34-36).
`There are three types of phases of liquid crystals: smec-
`tic, nematic, and cholesteric. These three types are illus-
`trated in Fig. 7 and compared with an ordinary isotropic
`liquid. The three phases differ in the nature of the
`crystal-like ordering. In the smectic phase, the long mole-
`cules form layers, approximately 20 A thick, that slide
`easily over each other. The molecules can move freely
`within each smectic plane but can not move between
`planes. In the nematic phase the long axes of the mole-
`cules are oriented in a specific direction as in the smectic
`phase, but the molecules are not stratified into layers.
`In the cholesteric phase the average ordering direction of
`the molecules varies in helical fashion with the helical axis
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`perpendicular to the long axes of the molecules. The cho-
`lesteric and nematic phases are the two phases of primary
`interest for display device applications.
`The liquid crystal phase is an intermediate phase (or
`“mesophase”) between the crystalline solid phase and the
`isotropic liquid phase. That is, as the temperature of the
`solid material is raised, it passes first into the liquid crys-
`tal phase and then at higher temperature to the isotropic
`liquid phase. The mesophase has a definite range of tem-
`perature stability. At the upper phase transition tempera-
`ture, the liquid crystal goes into the isotropic state and
`returns reproducibly to the mesophase upon cooling.
`This upper phase transition is sometimes called the clear-
`ing point since at this temperature the material changes
`from a milky liquid crystal to a clear isotropic liquid. The
`crystal-to-mesophase transition is also reversible in many
`cases, although for some materials the mesophase can ex-
`hibit supercooling with respect to the solid phase.
`A large number of chemical compounds exhibit liquid
`crystal behavior. These include azoxy compounds, anils,
`and esters. Mixtures of two liquid crystal materials are
`often used in display devices since it is sometimes found
`that the range of temperature stability for the liquid crys-
`tal phase is larger for the mixture than for either compo-
`nent by itself.
`The light modulating properties of liquid crystals result
`from the fact that the orientation of the long axis of the
`rod-like molecules can be afl‘ected by applied electric
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`ORDINARY LIQUID
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`Fig. 7 - Molecular ordering in three liquid crystal phases compared to
`ordinary liquid
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`fields and the optical properties of the liquid crystal de-
`pend on the orientation of the molecules. Many of the
`physical parameters of a liquid crystal are highly aniso-
`tropic. This includes the dielectric constant, the optical
`index of refraction, the electrical conductivity, and the
`viscosity. Because of the large optical anisotropy, a large
`change in the optical properties of the liquid crystal takes
`place when the liquid crystal ordering is perturbed by an
`external stimulus such as an applied electric field.
`A liquid crystal display device typically consists of a
`thin layer (5-20 pm) of liquid crystal material sandwiched
`between two glass plates as illustrated in Fig. 8. The glass
`plates contain coatings of conductive electrodes, and at
`least one of these electrodes must be transparent. The
`device must be hermetically sealed since moisture and
`oxygen have a deleterious effect on liquid crystal mate-
`rials.
`
`Liquid crystal displays can be either transmissive or re-
`flective. The difference is illustrated in Fig. 9 for a dy-
`namic scattering display. In the transmissive mode the
`source of the light that carries information to the observer
`is on the opposite side of the display from the observer;
`the light passes through the display, is modulated by the
`liquid crystal, and passes to the observer as in Fig. 9a.
`Note that the source of the light may be ambient light or
`it may be a separate light source. In the reflective mode
`the light source is on the same side of the display as the
`observer. Light passes through the liquid crystal material
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`VALEO EX. 1032_009
`VALEO EX. 1032_009
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`944
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`SEAL
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`GLASS PLATE
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`LIQUID CRYSTAL
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`GLASS PLATE
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`J. F. NOLAN
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`ANALYZER
`: \
`L l
`2%. 33%
`“MUM
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` 3 l
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`Fig. 8 - Liquid crystal display device
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`v= o VOLTS
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`\ POLARIZER / v= I0 VOLTS
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`be oass-:RvER?——>A
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`PARALLEL
`POLARIZERS
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`LIGHT
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`LIGHT
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`QUIESCENT
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`ACTIVATED
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`OPTICAL
`TRANSMISSION
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`(0) TRANSMISSIVE
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`A
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`A
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`\
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`CROSSED
`POLARIZERS
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`ouusscsm
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`ACTIVATED
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`(bl REFLECTIVE
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`Fig. 9 - Transmission and reflection modes of liquid crystal display
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`and is reflected from the back electrode to the observer.
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`As in the transmissive mode, the light source may be am-
`bient light, or it may be a separate light source. For trans-
`missive type devices both the front and back electrodes
`must be transparent; for reflective devices the front elec-
`trode must be transparent, and the back electrode must
`be a good reflector.
`A number of different kinds of liquid crystal devices
`have been proposed and investigated. These include de-
`vices which make use of dynamic scattering, twisted ne-
`matics, field induced birefringence, cholestericnematic
`transitions, and guest-host effects. Of these the two that
`have become most important for display devices are the
`dynamic scattering and twisted nematic devices and these
`will now be briefly described.
`A dynamic scattering device uses a nematic phase
`liquid crystal layer which is transparent in the unacti-
`vated state. The resistivity of the liquid crystal material
`is typically in the range 109-10“ (2 cm. The application
`of a potential difference across the device causes a cur-
`rent to flow, and this electrical current leads to a fluid
`flow in the liquid crystal material. The fluid flow causes
`turbulence which causes scattering of light because of
`the spatial variation in the index of refraction. All unac-
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`VOLTAGE
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`Fig. 10 - Twisted nematic liquid crystal display
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`tivated areas will appear black and activated areas will
`scatter light toward the viewer and will appear bright.
`If a dynamic scattering device is to be used in the reflec-
`tive mode, a mirror-like surface is required for the back
`electrode. Since no polarizers are included in the device,
`bright objects in the ambient can be specularly reflected,
`which can make the display difficult to read. In a
`dynamic scattering display current is flowing all the
`time an area is activated. However the current is very
`small, and typical power dissipation is on the order of
`l uW/cm’. Voltages are typically around 15 V.
`A twisted nematic device is an example of a field ef-
`fect liquid crystal display. That is, the material is acti-
`vated by the application of an electric field; it is not nec-
`essary for a conduction current to flow to keep the de-
`vice activated. Fig. l0 illustrates the operation of a
`twisted nematic device. The molecules of the nematic
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`liquid crystal are caused to line up in one direction at
`one of the electrodes by forming parallel microgrooves
`on the electrode surface. At the opposite electrode mi-
`crogrooves are formed in a direction perpendicular to
`the first set, causing molecules of the liquid crystal to
`line up in a direction that gradually rotates or twists
`through 90 deg across the cell. The resulting liquid crys-
`tal layer is optically active and will rotate the plane of
`polarization of incident light through 90 deg. If a polar-
`izer and analyzer are placed with the same polarization
`direction the transmission will be zero with no applied
`voltage. Applying a voltage causes the molecules to
`VALEO EX. 1032_010
`VALEO EX. 1032_010
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_011
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_012
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_013
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_014
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`Downloaded from SAE International by Ralph Wilhelm, Friday, August 29, 2014
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`VALEO EX. 1032_015