WO1989000300A1 - Ecran polychrome - Google Patents
Ecran polychrome Download PDFInfo
- Publication number
- WO1989000300A1 WO1989000300A1 PCT/FR1988/000359 FR8800359W WO8900300A1 WO 1989000300 A1 WO1989000300 A1 WO 1989000300A1 FR 8800359 W FR8800359 W FR 8800359W WO 8900300 A1 WO8900300 A1 WO 8900300A1
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- WIPO (PCT)
- Prior art keywords
- display
- walls
- materials
- liquid crystal
- polychrome
- Prior art date
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Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1347—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
- G02F1/13475—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells in which at least one liquid crystal cell or layer is doped with a pleochroic dye, e.g. GH-LC cell
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/133377—Cells with plural compartments or having plurality of liquid crystal microcells partitioned by walls, e.g. one microcell per pixel
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2203/00—Function characteristic
- G02F2203/34—Colour display without the use of colour mosaic filters
Definitions
- the present invention relates to a poLychrome screen, in particular a matrix screen.
- the invention applies in particular in optoelectronics and mainly to liquid crystal or electroluminescent display cells used for example as converters of electrical information into optical information, for the processing of optical images in real time and for analog display. .
- Monochrome and polychrome screens comprise, in a known manner, a display cell comprising at least a first and a second insulating wall facing each other, between which is inserted a display material whose optical characteristic can be modified .
- This material can be a solid and / or a liquid and / or a liquid crystal.
- the optical property of this material can be an opacity, a refractive index, a transparency, an absorption, a diffusion, a convergence, a rotary power, a birefringence, an intensity reflected in a determined solid angle, etc.
- the optical characteristic of the liquid crystal is modified by an "* electric field.
- This electric field is created between electrodes disposed respectively on the first and second walls of the cell facing the liquid crystal.
- these electrodes can be formed by a continuous electrode placed on one of the walls of the cell and brought to a reference potential and by Electrode points arranged on the other wall of the cell.
- the point electrodes are connected to row conductors and to column conductors by transistors such as thin film transistors.
- Electrodes can also be formed as described in patent application FR-A-2553 218 by column electrodes placed on one of the walls of the cell and by point electrodes placed on the other wall of the cell, the point electrodes being connected to line conductors and to a reference potential by transistors such as thin film transistors.
- these electrodes can be formed by column electrodes placed on one of the walls of the cell and by line electrodes placed on the other wall of the cell, the row and column electrodes being crossed.
- An elementary image point of a cell comprising a display material interposed between two insulating walls, is therefore defined by a capacitor whose armatures are formed in the case of a non-multiplexed display by a point electrode and by the part of the electrode continues opposite or by a point electrode and the part of a column electrode opposite, and in the case of a display multiplexed by the opposite parts of a line electrode and a column electrode;
- the display material inserted between said frames constitutes the dielectric of the capacitor.
- polychrome screens As is known, there are two main types of polychrome screens: polychrome screens of additive type and polychrome screens of subtractive type.
- Additive-type polychrome screens use colored filters arranged either inside or outside a display cell comprising a single display material consisting of a liquid crystal.
- the polychrome screens of the subtractive type use several display materials superimposed on each other, inside a display cell, each display material being constituted by a liquid crystal mixed with a different dye.
- a dichroic display material will be called a display material comprising a colorant.
- the Liquid crystal used in the polychrome screens described above is of the nematic type.
- the nematic type liquid cristaL molecules are said to be in homeotropic configuration H when they have their longitudinal axis perpendicular to the plane of the walls of the cell and and they are said to be in planar configuration P when they have their axis parallel to the plane of the walls.
- the configuration of the Liquid crystal molecules inserted between two electrodes of a cell depends on the nature of the Liquid crystal and on the electric field applied between these two electrodes.
- FIGS. 1a and 1b show diagrammatically a polychrome display cell of additive type comprising respectively colored filters 11a, 11b inside and outside the cell.
- a first and a second insulating and transparent walls 1, 3 are shown, between which a layer of liquid crystal 5 of the nematic helical type is interposed.
- transparent electrodes 7, 9 constituted for example respectively by a continuous electrode 7 and point electrodes 9. moreover, outside the cell, on the wall
- the polarizer 1 is arranged a straight line polarizer 15 and above. of the wall 3 is disposed a straight line polarizer 17.
- the polarizers 15 and 17 are crossed; the direction 15P of the polarizer 15 is for example parallel to the axis of the liquid crystal molecules in planar configuration located on the wall 1 while the direction 17P of the polarizer 17 is parallel to the axis of the liquid crystal molecules in planar configuration located on wall 3.
- the polarizer 17 makes it possible to straighten the incident light which enters the cell, for example from the wall 3 and the polarizer 15 makes it possible to absorb the incident radiation when the molecules of the liquid cristaL are in homeotropic configuration.
- the polarizer 17 is located on the wall 3 and the colored filters 11a are arranged inside the cell on the electrodes 9, so that each filter is opposite a zone of liquid crystal. inserted between a point 9 electrode and the continuous electrode 7.
- Each point 9 electrode and the part of the continuous electrode 7 opposite said electrode 9 constitute the reinforcements of a capacitor of which the liquid cristaL 5 interposed between these electrodes forms The dielectric.
- Each capacitor constitutes an elementary image point 10a of the polychrome screen.
- an image point of the screen consists of three adjacent elementary image points 10a, each of them being associated with a different filter, for example red, green, blue.
- the association of a red filter with molecules of Liquid crystal in planar configuration makes it possible to absorb Radiation corresponding to blue and green and to transmit Radiation corresponding to red
- the association of a green filter with molecules of liquid cristaL in planar configuration allows to absorb the radiations corresponding to red and blue and to transmit the radiations corresponding to green
- the association of a blue filter with molecules of liquid crystal in planar configuration makes it possible to absorb the radiations corresponding to red and green and to transmit the radiation corresponding to blue.
- liquid crystal molecules of the image point To display one of the three colors, bLeu, red, or green, at an image point, The liquid crystal molecules of the image point, associated with the filter whose color you want to display, must be in planar configuration and the molecules of this point associated the other two filters must be in homeotropic configuration. To display a white image point, Liquid crystal molecules, associated with the three filters of the image point, must be in planar configuration and to display a black image point, the liquid crystal molecules, associated with the three filters of the image point, must be in homeotropic configuration.
- the trichromy allows by combination of the three colors, and by the independent control of each of them, to obtain all the nuances of the visible spectrum by modulating independently the intensity of these colors.
- the colored filters 11b are arranged outside the cell between the external face of the wall 3 and a transparent wall 13, each filter being opposite an elementary image point 10b constituted by an electrode point 9 , the part of the continuous electrode 7 opposite the electrode point 9 and the liquid crystal zone interposed between these electrodes.
- Each image point of the screen also consists of three adjacent elementary image points, each of these three elementary image points being opposite three filters
- the wall 3 is advantageously thinner than that shown in FIG. 1a, in order to minimize the effects of parallax.
- the polarizer 17 is arranged on the external face of the wall 13.
- Additive-type polychrome screens use only one layer of liquid crystal 5; however, given that an image point is defined by three elementary image points, the light output of such screens is not satisfactory: only one third of the image point is used each time a blue, red or green at an image point.
- FIG. 2a schematically represents a polychrome display cell of the subtractive type.
- This cell comprises three superimposed display materials 25a, 25b, 25c, sandwiched respectively between insulating and transparent walls 21 and 22, 22 and 23, 23 and 24.
- These display materials 25a, 25b, 25c are constituted by a nematic liquid cristaL mixed with a dye.
- the walls 22 and 23 have thicknesses less than those of the walls 21 and 24 to minimize the effects of parallax. For example.
- the walls 22 and 23 have a thickness greater than or equal to about 100 ⁇ m
- the walls 21 and 24 have a thickness of the order of 1 mm
- the display materials 25a, 25b, 25c have a thickness of the order from ICL m.
- a straight line polarizer 30 is placed outside the cell, for example on the wall 21.
- the direction of polarization 30P is parallel to the axis of the liquid crystal molecules in planar configuration.
- Electrodes are arranged on the internal faces of these walls 21, 22, 23 and 24.
- a continuous electrode 27a and point electrodes 29a on the facing faces of the walls 21 and 22 are disposed, respectively, a continuous electrode 27a and point electrodes 29a; on the facing faces of the walls 22 and 23 are arranged, respectively, a continuous electrode 27b and point electrodes 29b and on the facing faces of the walls 23 and 24 are arranged, respectively, a continuous electrode 27c and point electrodes 29c.
- the dye molecules used in a dichroic display material have the property of being driven by the orientation of the Liquid crystal molecules; the absorbance of the dichroic display material varies depending on the orientation of said dye molecules.
- the dichro que display material is absorbent and when they are in homeotropic configuration, the display material lets light pass.
- the different dyes used in The three display materials 25a, 25b, 25c make it possible to absorb different wavelengths of light, when the molecules corresponding to these materials are in planar configuration.
- each image point 28 is defined by the superposition of three capacitors, the dielectrics of which are constituted respectively by the display materials 25a, 25b and 25c and the frames of which consist respectively of a point electrode 29a and the part of the electrode 27a facing, by a point electrode 29b and the part of the electrode 27b facing, and by a point electrode 29c and the part of the electrode 27c facing.
- FIG. 2b represents in an ideal case the transmission curves TCa), T (b), T (c) of each of the dichroic display materials 25a, 25b and 25c as a function of the wavelengths, when the molecules of each of these materials are in a planar configuration, in other words when these materials are in an absorbent state.
- the value 1 corresponds to a wavelength transmission and
- the value 0 corresponds to an absorption of wavelengths.
- the visible spectrum is broken down into radiation of wavelength ranging from 0.4 to 0.5 m corresponding to blue, into radiation of wavelength ranging from 0.5 to 0.6 ⁇ m corresponding green and radiation of wavelength from 0.6 to 0.7 m corresponding to red.
- the display material 25a in an absorbing state, the display material 25a ( see T (at ) FIG. 2b) lets through radiation of wavelength less than 0.6 ⁇ m and absorbs radiation of wavelength greater than 0, 6 m.
- the display material 25a therefore allows the radiation corresponding to blue and green to pass through and absorbs the radiation corresponding to red.
- the display material 25b ( see T ( b ) figure 2b) Passes radiation of wavelength less than 0.5 u and greater than 0.6i_.m while it absorbs radiation wavelength from 0.5 to 0.6 ⁇ ⁇ m.
- the material 25b therefore lets through the radiation corresponding to blue and red and absorbs the radiation corresponding to green.
- the display material 25c In an absorbent state, the display material 25c (see T (c) figure 2b) allows radiation of wavelength greater than 0.5 "m to pass through and absorbs radiation of wavelength less than 0.5" ⁇ .
- the material 25c therefore allows the radiation corresponding to green and red to pass through and absorbs the radiation corresponding to blue.
- the corresponding molecules of material 25b and of material 25c must be in planar configuration and the corresponding molecules of material 25a must be in homeotropic configuration.
- To display a green image point The corresponding molecules of the material 25a and the material 25c must be in the planar configuration and the corresponding molecules of the material 25b must be in the homeotropic configuration.
- To display a blue image point the corresponding molecules of material 25a and of material 25b must be in planar configuration and the corresponding molecules of material 25c must be in homeotropic configuration.
- the wavelengths transmitted correspond to those transmitted by the material in planar configuration, we thus obtain the superposition of two colors.
- modulating the electric field between the different electrodes between total absorption (value 0) and total transmission (value 1) it is also possible to obtain all the nuances of the visible spectrum for an image point.
- a polychrome screen of the subtractive type is more complex than a polychrome screen of the additive type and requires the use of three display materials separated by walls which, despite their small thickness, produce parallax effects.
- polychromatic screens of the subtractive type due to the superposition of the three display materials, nevertheless have a low brightness and therefore a high energy consumption also not allowing to be used in reflective mode.
- the subject of the invention is a new polychrome screen making it possible in particular to overcome the drawbacks of the polychrome screens described above and in particular having a better light output and therefore a lower energy consumption than the polychrome screens of additive and subtractive type described above.
- the polychrome screens according to the invention can be used both in reflective mode and in transmissive mode.
- the subject of the invention is a polychrome screen characterized in that it comprises alternating regions of first and second dichroic display materials inserted between first and second insulating walls and regions alternating third and fourth dichroic display materials sandwiched between the second and third insulating walls, each region of the first material being superimposed both on a region of the third material and on part of a region of the fourth material and each region of the second material being superimposed on the other part of a region of the fourth material, an image point of the screen being defined by the superposition of three adjacent capacitors of a first family ⁇ which have dielectric layers are made for two of them by the first material and for the third by the second material 'with three adjacent capacitors of a second family, the dielectrics of which consist of one of them by the third material and for the other two by the fourth material, the armatures of the capacitors of the first and of the second families being respectively constituted by electrodes arranged on the faces facing the first and the second walls and by electrodes arranged on the facing faces of the second and third
- the second and third display materials are identical.
- Each elementary image point of this screen is therefore constituted by the superposition of two capacitors, the dielectrics of which are formed by two different dichroic display materials instead of three capacitors in the case of polychromatic screens of the subtractive type.
- an image point of the polychrome screen according to the invention is defined from three adjacent elementary image points.
- Each elementary image point is capable of having at least four states: a black state, a white state and two colored states, each color being able to be obtained on two elementary image points instead of a single elementary image point as in the case of Additive type polychrome screens.
- the polychrome screens according to the invention have a high brightness corresponding to approximately 2/3 of the incident intensity and allowing display both in reflective mode and in trans issive mode.
- the distribution of each display material between the corresponding walls of the screen has a comb shape, the distribution of the first and second materials being complementary and the distribution of the third and fourth materials being complementary.
- each display material consists of a polymer comprising bubbles containing a liquid crystal mixed with a dye.
- a display material of this type is for example described in SID (society for Information Display) International
- each display material is constituted by a liquid cristaL mixed with a dye
- a first waterproof wall located between the first and the second walls allows to separate the first and the second display material
- a second waterproof wall located between the second and the third wall makes it possible to separate the third and the fourth display material, a first and a second seal being inserted respectively around the first and from the second wall and around the second and third wall.
- the first and second walls are produced respectively on the first or second walls and on the second or third walls above the electrodes, by conventional methods such as photolithography.
- these walls are formed by a poly erized resin, etched chemically or by plasma depending on the type of resin used.
- the liquid crystal used is of the type nematic.
- nematic liquid cristaL is understood to mean both nematic, helical nematic and nematic liquid crystals mixed with a cholesteric compound.
- the dichroic effect of the Heilmeir-Zanoni type requires a display material comprising a liquid crystal of the nematic type and a dye.
- this material When this material is inserted between two electrodes, if the electric field established between the two electrodes is sufficient to excite the liquid crystal molecules, the liquid crystal and dye molecules are in planar configuration: the display material is then absorbent ; otherwise.
- the molecules of liquid cristaL and dye come in a homeotropic configuration: the display material is passing, in other words it transmits incident light. With this type of display material, absorbent -The state corresponds to an excited state and the on state to a non-excited state.
- absorbing state is meant a state allowing the absorption of only part of the wavelengths of the incident light and by passing state, a state allowing the complete transmission of the wavelengths of the incident light.
- a polarizer When the display cell according to the invention uses such display materials, a polarizer must be associated with the cell.
- the White-Taylor type dichroic effect requires a display material comprising a nematic type liquid crystal mixed with a cholesteric compound and a dye.
- this material When this material is interposed between two electrodes, if the electric field established between the two electrodes is sufficient to excite the liquid crystal molecules. Liquid crystal and dye molecules present in homeotropic configuration, the display material is passable; otherwise, the liquid crystal and dye molecules occur successively in all directions, and the display material is absorbent. With this type of display material, the absorbing state corresponds to an unexcited state and the state passing to an excited state.
- the display cell according to the invention uses such display materials, it does not require a polarizer given the numerous directions taken by ⁇ J0 the molecules of liquid cristaL and dye in the non-excited state .
- This cell without polarizer has better brightness than a cell with one or more polarizers.
- a helical nematic type liquid crystal can also be used
- the display cell requires two crossed polarizers.
- the nematic liquid crystal molecules have
- the liquid crystal used is ferroelectric, in other words it is of the tilted chiral smectic type 5 and for example of the chiral smectic type C.
- An inclined chiral smectic liquid crystal is made up of elongated chirray molecules arranged in layers.
- the molecules are inclined at an angle ⁇ with respect to the normal to the layers and have a 0 P dipole moment perpendicular to their longitudinal axis.
- the liquid crystal layers are mutually parallel and 5 perpendicular to the cell walls and the molecules of Liquid crystal are in planar configuration.
- the Longitudinal axis of the molecules makes an angle - ⁇ with respect to the normal to the layers
- the Longitudinal axis of the molecules makes an angle + ⁇ with respect to the normal to the layers.
- a polychrome screen according to the invention using a ferroelectric liquid crystal associated with dyes, comprises a threshold. polarizer; this poLarizer is placed for example so that the incident light crosses the polarizer before entering the cell.
- the angle 29 is preferably equal to 90 °. Indeed, the smaller the angle 2 ⁇ , the less the contrast between an absorbing state and a passing state.
- the display material When the Longitudinal axis of the ferroelectric liquid crystal molecules is parallel to the direction of the polarizer, the display material is absorbent and when it is perpendicular, the display material is conducting.
- ferroelectric liquid crystals Since ferroelectric liquid crystals have the property of keeping their orientation out of field, this type of screen does not require refreshing.
- La as the switching speed between the two stable states of the ferroelectric liquid crystal molecules is rapid, of the order of a few seconds, a display of multiplex type such as that described above is advantageously used with this type of liquid crystal.
- non-multiplex displays can also be used.
- the first material absorbs the radiation corresponding to green and red and transmits the radiation corresponding to blue
- the second and the third material absorb the radiation corresponding to blue and green and transmit the radiation corresponding to red
- the fourth material absorbs the radiation corresponding to blue and red and transmits the radiation corresponding to green.
- FIGS. 1a and 1b already described, schematically represent in section of the polychrome display cells of the additive type
- FIG. 2a already described, schematically represent in section a polychrome display cell of the subtractive type
- - FIG. 2b already described, represents the transmission curves of the dichroTque display materials used in the cell represented in FIG. 2a, for the different wavelengths of the visible spectrum
- FIG. 3a schematically represents an example of a display cell according to the invention, each display material of which consists of a liquid cristaL mixed with a dye and the display of which is of the multiplex type,
- FIG. 3b shows schematically in section the display cell of Figure 3a
- FIG. 3c schematically shows the curves transmission of an example of display materials used in a display cell according to the invention, for the different wavelengths of the visible spectrum
- FIG. 4 shows schematically another example of a display cell according to the invention for which each display material is constituted by a polymer comprising bubbles containing a liquid cristaL mixed with a dye and whose display is of the type non-multiplexed
- - Figure 5 schematically represents the two stable states of the cristaL molecules Ferroelectric liquid used in a display cell according to the invention associated with a single polarizer.
- Figures 3a and 3b schematically show respectively in exploded view and in section an example of a display cell according to the invention.
- This cell has three insulating walls 31, 33,
- a wall 41 to separate this space into two distinct zones 41A, 41B; each of these areas has the shape of a complementary comb.
- the regions 40A corresponding to the teeth of the comb formed by the area 41A are alternated with the regions 40B corresponding to the teeth of the comb formed by the area 41B; the width of the regions 40A is greater than that of the regions 40B, it is for example equal to twice the width of the regions 40B.
- a wall 43 is arranged to divide this space into two distinct zones 43B and 43C, each of these zones having the shape of a comb. complementary.
- the regions 42B corresponding to the teeth of the comb formed by the area 43B are alternated with The regions 42C corresponding to the teeth of the comb formed by zone 43C;
- Width of regions 42C is greater than that of regions 42B, it is for example equal to twice the width of regions
- the walls 41 and 43 are arranged respectively between
- each region 40B is superimposed on a part of a region 42C, and that each region 40A is superimposed on the other part of a region 42C and on a region 42B.
- the different zones 41A, 41B, 43B, 43C are filled respectively with dichroic display materials, by means of filling holes 45 arranged for example in the walls 31 and 35, opposite said zones.
- Each of these display materials consists of a Liquid crystal, for example of the nematic or ferroelectric type and a dye.
- the area 40A contains a display material A whose colorant is chosen so that in the absorbing state the transmission curve T of this material is close to the curve T (A) shown in FIG. 3c, in other words, be equal to 1 for radiation of wavelength less than 0.5i ⁇ .m and more particularly for radiation of wavelengths ranging from 0.4 to 0.5 I A .IT "and be equal 0 for other radiations.
- Zones 40B and 42B contain a display material B whose colorant is chosen so that in the absorbing state the transmission curve of this material is close to the curve T (B) shown in the figure
- Zone 42C contains a display material C, the dye of which is chosen so that
- the absorbing state of the transmission curve of this material is close to the curve T (C) shown in Figure 3c, in other words is equal to 1 for radiation of wavelength ranging from 0.5 to 0.6 m and be zero for others radiation.
- the wavelengths from 0.4 to 0.5 ⁇ ⁇ .m correspond in the visible spectrum to blue, this l the
- 0.5 to 0.6 t__m correspond to green and those ranging from 0.6 to
- 0.7 d.m corresponds to red.
- the relative values 1 and 0 of these transmission curves correspond respectively to transmissions and to absorptions.
- the material at A absorbs the radiation corresponding to green and red and transmits that corresponding to blue.
- the material at B absorbs the radiation corresponding to blue and green and transmits that corresponding to red and
- the material at C absorbs the radiation corresponding to blue and red and transmits The radiation corresponding to green.
- the dye contained in the material A can be a blue dye F sold by Merck, Le
- C can be a mixture of yellow F and green F dyes
- FIG. 3a also shows, by way of example, a display of the multiplex type.
- the excitement of the display materials is therefore obtained by the creation of an electric field between row electrodes and crossed column electrodes.
- row 31a electrodes and column electrodes 33a crossed with the row electrodes 31a and on the facing faces of the walls 33 and 35 are arranged H column electrodes 33b and Row 35a electrodes crossed with Column electrodes 33b.
- H column electrodes 33b and Row 35a electrodes crossed with Column electrodes 33b are arranged so that each region 40A is opposite two column electrodes 33a, each region 40B is opposite a column electrode 33a, each region 42B is opposite a column electrode 33b and finally each region 42C or opposite two column electrodes 33b.
- the facing parts of the row electrodes and of the column electrodes form the armatures of capacitors, the display materials of which inserted between said parts form the dielectrics.
- the walls 31 and 33 of the cell are defined a first family of capacitors from the electrodes 31a and 33a and the display materials A and B, each region 40A being associated with a first and a second column of capacitors of the first family and each region 40B being associated with a single column of capacitors of the first family.
- each region 42B being associated with a single column of capacitors of the second family and each region 42C being associated with a first and a second column of capacitors of the second family.
- first column of capacitors associated with each region 40A is superimposed on the column of capacitors associated with a region 42B
- the second column of capacitors associated with each region 40A is superimposed on the first column of capacitors associated with a region 42C
- the column of capacitors associated with each region 40B is superimposed on the second column of capacitors associated with a region 42C.
- Each elementary image point 50 of the cell corresponds to the superposition of a capacitor of the first family with a capacitor of the second family, the dielectrics of which are formed by different display materials.
- the display cell according to the invention therefore comprises three different types of elementary image points corresponding respectively to the superposition of the materials A-B, the materials AC and the materials BC.
- An image point 52 of the cell is therefore defined by three adjacent elementary image points of different types corresponding for example to the superposition of the materials AB, AC and BC.
- the table below gives the different states obtained with the screen according to the invention, for the three pointa elementary images constituting an image point of the screen.
- State 1 corresponds to an absorbing state in other words following the dichroic display material, certain wavelengths are transmitted and others are absorbed and state 0 corresponds to a total transmission of the Lengths of wave.
- the color resulting from this superposition is white.
- Material A is in an absorbing state (state 1) and Material B in a passing state, only material A absorbs Light radiation; the resulting color is therefore blue.
- the material A is in a passing state and the material B in an absorbing state, only the material B absorbs light radiation; the resulting color is therefore red.
- the two superimposed materials A and B are in an absorbent state, Material A absorbs the radiation corresponding to green and red and Material B absorbs The radiation corresponding to blue and green; The resulting color is therefore black.
- each display material of an image point is associated with two elementary image points
- each blue, red or green color can be displayed on two elementary image points.
- the screen according to the invention can therefore display one of these colors on 2/3 of an image point instead of 1/3 for screens of the additive type, each color resulting from the superposition of two display materials on the Location of three as in Subtractive type display screens.
- the screen according to the invention therefore has a higher light output than that of screens of the additive or subtractive type, which makes it possible to use the screens according to the invention both in reflective mode and in transmissive mode.
- a reflector is required for the cell.
- the reflector is arranged for example on the external or internal face of the wall 35 or else it is constituted by this wall 35.
- In reflective mode at least the all the walls located upstream of the reflector is transparent and in transmissive mode, all the walls of the cell are transparent.
- FIG. 3a a multiplex type display has been shown, but depending on the type of liquid crystal used in the screen according to the invention, it may of course be more advantageous, as we have seen previously, to use a non-muLtiplexed display such as that shown in Figure 4.
- the cell shown in Figure 4 differs from that of the FIG. 3a by the nature of the dichroic display materials and by the type of display used.
- the display materials consist of polymers comprising bubbles containing a liquid crystal mixed with a dye. Due to the solid structure of the polymers, this cell does not require walls to separate the display materials two by two, nor seals, as in the case of FIGS. 3a and 3b.
- Each region 45B ' is superimposed on a part of a region 47C, and each region 45A' is superimposed on the other part of a region 47C and on a region 47B '; the width of the regions 45A 'and 47C is for example equal to twice the width of the regions 45B' and 47B '.
- the dyes of the display materials A ', B' and C are for example of the same type as those of the display materials A, B and C described above with reference to Figures 3a, 3b and 3c.
- FIG. 4 an example of a non-multiplex display is shown; this display uses continuous electrodes and point electrodes.
- 33 and 31 are respectively arranged a continuous electrode 33c and point electrodes 31c, and on the facing faces of the walls 35 and 33 are respectively arranged point electrodes 35c and a continuous electrode 33e.
- the point electrodes 31c are arranged so that each region 45B 'faces a column of point electrodes 31c and that each region 45A' faces two columns of point electrodes 31c; the point electrodes 35c are arranged so that each region 47B 'faces a column of point electrodes 35c and that each region 47C faces two columns of point electrodes 35c.
- Each point electrode 31c, 35c is connected in a known manner to a line conductor and to a column conductor (not shown) by means of a transistor (not shown) such as a thin film transitor, so that for example When the electrical signal conveyed by the corresponding column conductor causes the on state of the transistor, the electrical signal conveyed by the line conductor is transmitted to the point electrode. Furthermore, the continuous electrodes are at a reference potential.
- Each point electrode and the part of the continuous electrode facing the point electrode constitute the armatures of a capacitor and the display material interposed between these armatures forms the dielectric of this capacitor.
- the walls 31 and 33 of the cell is defined a first family of capacitors and between the walls
- each region 45B 'and 47B' being associated with a single column of capacitors of the first and second families respectively and each region 45A 'and 47C being associated with a first and a second columns of capacitors of the first and second families respectively.
- the first column of capacitors associated with each region 45A ' is superimposed on the column of capacitors associated with a region 47B'
- the second column of capacitors associated with each region 45A '3 ⁇ t superimposed on the first column of capacitors associated with a region 47C * and the column of capacitors associated with each region 45B 'is superimposed on the second column of capacitors associated with a region 47C'.
- an elementary image point of the cell is constituted by the superposition of a capacitor of the first family with a capacitor of the second family whose display materials are different and an image point of the cell corresponds to three adjacent elementary image points, each of these elementary image points corresponding to a different superposition of two display materials, for example A'-B ', A'-C * and B'-C.
- the wall 33 is thinner than the walls 31 and 35.
- the walls 31 and 35 have a thickness of the order of 1 mm
- the wall 33 has a thickness less than or equal to 100 ⁇ m
- each display material has a thickness of the order of 1 to 20 ⁇ m.
- FIG. 5 schematically shows in exploded view part of a display cell according to the invention, the dichroic display materials include a liquid crystal of the ferroelectric type.
- ferroelectric liquid crystal and dye molecules have been represented only for a single elementary image point corresponding, as we have seen above, to the superposition of two capacitors, the dielectrics of which are respectively constituted by two display materials. distinct, for example A and B; the armatures of these capacitors are constituted for example respectively by the opposite parts of a row electrode 31a and a column electrode 33a and by the opposite parts of a column electrode 33b and of a line electrode 35a.
- this cell is associated with a polarizer 51 arranged for example above the wall 31 and whose direction is referenced by an arrow 53.
- the molecules of cristaL Ferroelectric liquid 55, 56 and of dye 57, 58 of the materials A and B are as we have seen previously in planar configuration.
- an electric field such as the axis of the liquid crystal and dye molecules 55, 57 is oriented between these electrodes parallel to the direction of the polarizer; the corresponding display material is then in an absorbent state.
- an electric field of reverse polarity when one establishes between two electrodes, for example 33b and 35a, an electric field of reverse polarity,
- the axis of the liquid crystal and dye molecules 56 and 58 is oriented between these electrodes perpendicular to the direction of the polarizer 51; the corresponding display material is then in a passing state.
- the molecules of liquid crystal and dye therefore make an angle 26 of the order of 90 °.
- ferroelectric liquid crystals with other multiplex display modes than that shown in FIG. 5 or non-multiplex display modes.
- these ferroelectric liquid crystals can, as described in FIG. 4, be in a polymer.
- the screens according to the invention are compatible with all the orientation techniques and surface treatment techniques of known screens, such as for example monochrome screens. They can also be used for large display areas.
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- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Mathematical Physics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Liquid Crystal (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI900053A FI900053A0 (fi) | 1987-07-07 | 1990-01-05 | Flerfaergad bildruta. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8709641A FR2618008B1 (fr) | 1987-07-07 | 1987-07-07 | Ecran polychrome |
FR87/09641 | 1987-07-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1989000300A1 true WO1989000300A1 (fr) | 1989-01-12 |
Family
ID=9352960
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR1988/000359 WO1989000300A1 (fr) | 1987-07-07 | 1988-07-05 | Ecran polychrome |
Country Status (6)
Country | Link |
---|---|
US (1) | US5015074A (fr) |
EP (1) | EP0377572A1 (fr) |
JP (1) | JPH03501064A (fr) |
FI (1) | FI900053A0 (fr) |
FR (1) | FR2618008B1 (fr) |
WO (1) | WO1989000300A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0347790A2 (fr) * | 1988-06-20 | 1989-12-27 | Honeywell Inc. | Unité d'affichage à cristal liquide et méthode pour afficher une image utilisant une telle unité |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR960002202B1 (ko) * | 1991-02-04 | 1996-02-13 | 가부시끼가이샤 한도다이 에네르기 겐뀨쇼 | 액정 전기 광학 장치 제작 방법 |
KR930005559B1 (ko) * | 1991-06-14 | 1993-06-23 | 삼성전관 주식회사 | 평판 디스플레이 장치 |
US5473450A (en) * | 1992-04-28 | 1995-12-05 | Sharp Kabushiki Kaisha | Liquid crystal display device with a polymer between liquid crystal regions |
US5289301A (en) * | 1992-06-12 | 1994-02-22 | Boit, Inc. | Liquid crystal color modulation displays with dyes of different orders and circuitry for providing modulated AC excitation voltage |
JP3074111B2 (ja) * | 1994-05-27 | 2000-08-07 | シャープ株式会社 | 液晶パネル及びその製造方法 |
JP3071658B2 (ja) * | 1994-11-02 | 2000-07-31 | シャープ株式会社 | 液晶表示素子 |
US5477354A (en) * | 1994-11-21 | 1995-12-19 | Rockwell International Corporation | Ferroelectric liquid crystal phase-only modulator with one ferroelectric liquid crystal spatial light modulator's smectic layers orthogonal to another's |
JPH08328031A (ja) * | 1995-06-02 | 1996-12-13 | Sharp Corp | フルカラー液晶表示装置およびその製造方法 |
JPH0926596A (ja) * | 1995-07-13 | 1997-01-28 | Sharp Corp | 液晶表示装置及びその製造方法 |
GB2321718A (en) * | 1997-01-31 | 1998-08-05 | Nat Science Council | LIquid crystal display |
US6020941A (en) * | 1998-02-12 | 2000-02-01 | Advanced Display Systems, Inc. | Stereographic liquid crystal display employing switchable liquid crystal materials of two polarities in separate channels |
US6795138B2 (en) * | 2001-01-11 | 2004-09-21 | Sipix Imaging, Inc. | Transmissive or reflective liquid crystal display and novel process for its manufacture |
US7382522B2 (en) * | 2005-04-29 | 2008-06-03 | Hewlett-Packard Development Company, L.P. | Grooved substrate |
DE102006017564B3 (de) * | 2006-04-13 | 2007-12-27 | Aeg Gesellschaft für Moderne Informationssysteme mbH | Farb- Flüssigkristallanzeigeeinrichtung |
KR101605821B1 (ko) * | 2010-09-10 | 2016-03-24 | 삼성디스플레이 주식회사 | 표시 장치 및 이의 제조 방법 |
Citations (3)
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EP0089378A1 (fr) * | 1981-09-30 | 1983-09-28 | Mitsubishi Denki Kabushiki Kaisha | Unite d'affichage a cristaux liquides en couleur |
FR2561020A1 (fr) * | 1984-03-07 | 1985-09-13 | Stanley Electric Co Ltd | Dispositif d'affichage a cristal liquide de type matriciel a couches multiples |
WO1986005282A1 (fr) * | 1985-03-01 | 1986-09-12 | Manchester R & D Partnership | Affichage a cristaux liquides en couleurs et procede |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS5792311A (en) * | 1980-11-28 | 1982-06-08 | Sharp Corp | Guest-host type liquid crystal display element |
JPS59219719A (ja) * | 1983-05-27 | 1984-12-11 | Seiko Instr & Electronics Ltd | カラ−液晶表示装置 |
US4581608A (en) * | 1983-06-13 | 1986-04-08 | General Electric Company | Multi-color liquid crystal display and system |
KR910007013B1 (ko) * | 1985-10-09 | 1991-09-14 | 가부시기가이샤 히다찌세이사꾸쇼 | 컬러액정표시소자 |
JPS6442633A (en) * | 1987-08-10 | 1989-02-14 | Koito Mfg Co Ltd | Liquid crystal display device for color display |
JP2594985B2 (ja) * | 1987-11-24 | 1997-03-26 | 株式会社日立製作所 | 液晶表示素子 |
-
1987
- 1987-07-07 FR FR8709641A patent/FR2618008B1/fr not_active Expired
-
1988
- 1988-07-05 EP EP19880905903 patent/EP0377572A1/fr not_active Ceased
- 1988-07-05 JP JP63506009A patent/JPH03501064A/ja active Pending
- 1988-07-05 US US07/465,074 patent/US5015074A/en not_active Expired - Fee Related
- 1988-07-05 WO PCT/FR1988/000359 patent/WO1989000300A1/fr not_active Application Discontinuation
-
1990
- 1990-01-05 FI FI900053A patent/FI900053A0/fi not_active IP Right Cessation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0089378A1 (fr) * | 1981-09-30 | 1983-09-28 | Mitsubishi Denki Kabushiki Kaisha | Unite d'affichage a cristaux liquides en couleur |
FR2561020A1 (fr) * | 1984-03-07 | 1985-09-13 | Stanley Electric Co Ltd | Dispositif d'affichage a cristal liquide de type matriciel a couches multiples |
WO1986005282A1 (fr) * | 1985-03-01 | 1986-09-12 | Manchester R & D Partnership | Affichage a cristaux liquides en couleurs et procede |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0347790A2 (fr) * | 1988-06-20 | 1989-12-27 | Honeywell Inc. | Unité d'affichage à cristal liquide et méthode pour afficher une image utilisant une telle unité |
EP0347790A3 (en) * | 1988-06-20 | 1990-08-22 | Honeywell Inc. | Liquid crystal display unit and method for displaying an image with such unit |
Also Published As
Publication number | Publication date |
---|---|
FI900053A (fi) | 1990-01-05 |
US5015074A (en) | 1991-05-14 |
FR2618008A1 (fr) | 1989-01-13 |
EP0377572A1 (fr) | 1990-07-18 |
FI900053A0 (fi) | 1990-01-05 |
FR2618008B1 (fr) | 1989-10-20 |
JPH03501064A (ja) | 1991-03-07 |
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