WO2010058799A1 - Élément optique et dispositif d'affichage - Google Patents

Élément optique et dispositif d'affichage Download PDF

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Publication number
WO2010058799A1
WO2010058799A1 PCT/JP2009/069577 JP2009069577W WO2010058799A1 WO 2010058799 A1 WO2010058799 A1 WO 2010058799A1 JP 2009069577 W JP2009069577 W JP 2009069577W WO 2010058799 A1 WO2010058799 A1 WO 2010058799A1
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Prior art keywords
optical element
liquid crystal
dye
solvatochromic dye
element according
Prior art date
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PCT/JP2009/069577
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English (en)
Japanese (ja)
Inventor
一 山口
励 長谷川
崇 宮崎
一志 永戸
春日 大岡
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株式会社 東芝
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Application filed by 株式会社 東芝 filed Critical 株式会社 東芝
Publication of WO2010058799A1 publication Critical patent/WO2010058799A1/fr
Priority to US13/111,591 priority Critical patent/US8531644B2/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B69/00—Dyes not provided for by a single group of this subclass
    • C09B69/10—Polymeric dyes; Reaction products of dyes with monomers or with macromolecular compounds
    • C09B69/109—Polymeric dyes; Reaction products of dyes with monomers or with macromolecular compounds containing other specific dyes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B53/00—Quinone imides
    • C09B53/02—Indamines; Indophenols
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B55/00—Azomethine dyes
    • C09B55/009—Azomethine dyes, the C-atom of the group -C=N- being part of a ring (Image)
    • 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

Definitions

  • the present invention relates to optical technology.
  • Electronic paper is a display device that can change the image to be displayed and has portability comparable to paper. Electronic paper can replace a portion of paper used for information transmission. Therefore, electronic paper can contribute to the protection of forest resources.
  • a color filter When a color filter is used to display a multicolor image in such a display device, it is difficult to achieve a high resolution and a thickness comparable to paper. Moreover, it is advantageous to change the image to be displayed by an electrical method. That is, it is desirable that a multicolor image can be displayed without a color filter.
  • Japanese Patent Application Laid-Open Nos. 2007-11260, 2007-240668, and 2007-279163 describe display technologies using an electrolytic solution containing metal ions.
  • a metal is deposited from the electrolytic solution by energizing the electrolytic solution.
  • the display color changes according to, for example, the particle size of the metal fine particles. Therefore, according to this display technique, it is possible to display a multicolor image without a color filter.
  • An object of the present invention is to enable display of a multicolor image with excellent color reproducibility.
  • an optical variable layer including a material having dielectric anisotropy and a solvatochromic dye, and first and second electrodes for applying a voltage to the optical variable layer are provided.
  • Provided optical elements are provided.
  • a display device including the optical element according to the first aspect and a drive circuit for applying a drive voltage between the first and second electrodes.
  • FIG. 11 is a perspective view schematically showing a state in which the optical element shown in FIG. 10 displays a magenta color.
  • FIG. 11 is a perspective view schematically showing a state in which the optical element shown in FIG. 10 displays a cyan color.
  • FIG. 11 is a diagram schematically showing solvatochromic dye molecules and liquid crystal molecules in the state shown in FIG. 10.
  • FIG. 12 is a diagram schematically showing solvatochromic dye molecules and liquid crystal molecules in the state shown in FIG. 11.
  • FIG. 13 is a diagram schematically showing solvatochromic dye molecules and liquid crystal molecules in the state shown in FIG. 12.
  • FIG. 17 is a cross-sectional view schematically showing how the optical element shown in FIG. 16 displays other colors. Sectional drawing which shows a mode that the optical element which concerns on the 4th aspect of this invention is displaying a certain color.
  • FIG. 19 is a cross-sectional view schematically showing how the optical element shown in FIG. 18 displays another color.
  • the graph which shows an example of the color change accompanying a voltage change.
  • Sectional drawing which shows the optical element which concerns on Example 3 roughly.
  • the graph which shows the other example of the color change accompanying a voltage change.
  • Solvatochromism is a phenomenon in which the color of a dye solution changes according to the type of solvent, and is interpreted as follows.
  • dipole moment means “electric dipole moment”
  • the magnitude of the dipole moment differs significantly between the ground state and the excited state.
  • One of the ground state and the excited state of the dye molecule is more stabilized as the polarity of the solvent is higher.
  • solvatochromism the electron transition energy from the ground state to the excited state changes, causing a shift in the absorption wavelength.
  • solvatochromic dye such a dye is called a solvatochromic dye.
  • ⁇ E and ⁇ E ′ represent the electron transition energy from the ground state to the excited state of the solvatochromic dye when the polarity of the solvent is low and when the solvent is high, respectively.
  • ⁇ (g) and ⁇ (ex) represent the dipole moment of the dye molecule in the ground state and the excited state, respectively.
  • ⁇ and n represent the dielectric constant and refractive index of the solvent, respectively.
  • L ( ⁇ ) and L (n 2 ) in equation (1) is a value calculated from equation (2).
  • Formula (1) is the difference between the electron transition energy ⁇ E ′ when the polarity of the solvent is high and the electron transition energy ⁇ E when the polarity of the solvent is low, that is, the change amount ⁇ E′ ⁇ E of the electron transition energy is the dipole moment.
  • This is a function of ⁇ (g) and ⁇ (ex) , a dielectric constant ⁇ , and a refractive index n, and is called a McRae model.
  • the angle formed between the dipole moment in the excited state and the dipole moment in the ground state is set to 0 ° (or 180 °).
  • the concept of solvent polarity includes hydrogen bonding and electron donating properties, but these are not considered in the McRae model.
  • FIG. 1 is a diagram showing an example of a dye exhibiting positive solvatochromism and dipole moments in its ground state and excited state.
  • FIG. 2 is a diagram showing an example of a dye exhibiting negative solvatochromism and dipole moments in its ground state and excited state.
  • FIG. 3 is an energy diagram of solvatochromism exhibited by the pigment shown in FIG.
  • FIG. 4 is an energy diagram of solvatochromism shown by the dye shown in FIG.
  • FIG. 1 shows a Phenol Blue dye as an example of a dye exhibiting positive solvatochromism.
  • FIG. 2 shows a Reichardt dye as an example of a dye exhibiting negative solvatochromism. Note that the structural formulas shown in FIGS. 1 and 2 do not necessarily accurately represent the electron density in the compound.
  • the solvatochromism is called a positive solvatochromism.
  • the polarity of the solvent is increased, the absorption wavelength is shifted in the long wavelength direction.
  • the solvatochromism is called a negative solvatochromism.
  • the polarity of the solvent is increased, the absorption wavelength is shifted in the short wavelength direction.
  • the value L (n 2 ) represents the electronic polarization
  • the difference L ( ⁇ ) ⁇ L (n 2 ) between the value L ( ⁇ ) and the value L (n 2 ) The orientation polarization is obtained by subtracting the polarization contribution.
  • the variation ⁇ E′ ⁇ E is large. That is, in this case, the color change amount of the pigment is large.
  • solvatochromism can be said to be a phenomenon derived from the interaction between the dipole of the dye molecule and the dipole of the solvent existing in the vicinity of the dye molecule and the induced dipole. Therefore, if the magnitude of this interaction can be changed by an electric field, the color of the solvatochromic dye, particularly the hue, should be changed without changing the solvent.
  • a material having dielectric anisotropy is positioned in the vicinity of the solvatochromic dye, and the material having dielectric anisotropy is compared with the material having dielectric anisotropy. An electric drive signal is given. This realizes a color change of the solvatochromic dye without changing the solvent.
  • FIG. 5 is a diagram schematically showing the relationship between the dipole moment of the dye molecule and the orientation state of the solvent molecule. Note that FIG. 5 assumes a case where a liquid crystal material is used as a material having dielectric anisotropy.
  • the polarity of the solvent cannot be simply interpreted by the dielectric constant, but here, based on the McRae model, the polarity of the solvent is considered by focusing on the dielectric constant.
  • the liquid crystal material is a material having a dielectric anisotropy that a dielectric constant parallel to the molecular long axis is different from a dielectric constant perpendicular to the long axis.
  • the dipole moment ⁇ dye of the solvatochromic dye molecule SD is parallel to the long axis of the liquid crystal molecule LC.
  • the dipole moment ⁇ dye of the solvatochromic dye molecule SD is perpendicular to the long axis of the liquid crystal molecule LC.
  • the solvatochromic dye molecule SD is placed in an environment having a dielectric constant ⁇ parallel to the long axis of the liquid crystal molecule LC.
  • the solvatochromic dye molecule SD is placed in an environment having a dielectric constant ⁇ perpendicular to the long axis of the liquid crystal molecule LC.
  • FIG. 6 is a diagram schematically showing the interaction between the dipole of the dye molecule and the dipole of the solvent molecule and the induced dipole.
  • the liquid crystal molecule LC is a nematic liquid crystal having positive dielectric anisotropy ( ⁇ > ⁇ ).
  • the induced dipole moment ⁇ LC ⁇ due to the refractive index ⁇ 0 ⁇ parallel to the short axis of the liquid crystal molecule LC is perpendicular to the dipole moment ⁇ dye of the dye molecule SD.
  • the dipole moment ⁇ LC of the liquid crystal molecule LC and the induced dipole moment ⁇ LC ⁇ caused by the refractive index ⁇ 0 ⁇ parallel to the long axis of the liquid crystal molecule LC are the dipole moment of the dye molecule SD. It is orthogonal to ⁇ dye . The interaction of orthogonal dipole moments is zero.
  • the dipole moment ⁇ LC of the liquid crystal molecule LC and the induced dipole moment ⁇ LC ⁇ caused by the refractive index ⁇ 0 ⁇ parallel to the long axis of the liquid crystal molecule LC are It interacts with the dipole moment ⁇ dye .
  • the induced dipole moment ⁇ LC ⁇ due to the refractive index ⁇ 0 ⁇ parallel to the short axis of the liquid crystal molecule LC interacts with the dipole moment ⁇ dye of the dye molecule SD.
  • the interaction energy received by the dipole moment ⁇ dye of the dye molecule SD in the orientation state A1 is ⁇ dye ⁇ LC / (4 ⁇ 0 r 3 ) ⁇ 2 ⁇ dye 2 ⁇ 0 ⁇ / ((4 ⁇ 0 ) 2 r 6 ).
  • the interaction energy received by the dipole moment ⁇ dye of the dye molecule SD in the orientation state A2 is ⁇ 2 ⁇ dye 2 ⁇ 0 ⁇ / ((4 ⁇ 0 ) 2 r 6 ).
  • ⁇ 0 represents the dielectric constant of vacuum
  • r represents the distance between the liquid crystal molecules LC and the dye molecules SD.
  • the interaction between the dipole of the dye molecule SD, the dipole of the liquid crystal molecule LC, and the induced dipole is larger than that in the alignment state A2.
  • the magnitude of this interaction correlates with the color of the solvatochromic dye.
  • the change between the alignment state A1 and the alignment state A2 can be caused by an electric field. Therefore, when a solvatochromic dye and a liquid crystal material are combined, the color of the solvatochromic dye can be changed by an electric field. Therefore, when this technique is used, a multicolor image can be displayed without a color filter.
  • the color of the solvatochromic dye correlates with the magnitude of the interaction between the dipole of the dye molecule SD, the dipole of the liquid crystal molecule LC, and the induced dipole. Therefore, when the electric field strength is changed between three or more values, three or more colors can be displayed. Therefore, when this technique is applied to a display device, a multicolor image can be displayed while adopting a relatively simple structure for the pixels.
  • the magnitude of the electric field can be controlled with high accuracy. Therefore, according to the technique described above, excellent color reproducibility can be achieved.
  • a liquid crystal display device using birefringence requires a polarizer.
  • the technique described above utilizes absorption of a solvatochromic dye, a wide viewing angle can be easily achieved.
  • this technique does not require a polarizer, so that bright display is possible.
  • FIG. 7 is a perspective view schematically showing that the optical element according to the first aspect of the present invention displays yellow.
  • FIG. 8 is a perspective view schematically showing how the optical element shown in FIG. 7 displays a magenta color.
  • FIG. 9 is a perspective view schematically showing that the optical element shown in FIG. 7 displays a cyan color.
  • the optical element 10 shown in FIGS. 7 to 9 is a reflective optical element.
  • the optical element 10 includes substrates 11a and 11b, a sealing layer (not shown), electrodes 12a and 12b, an optical variable layer 13, and a reflecting layer (not shown).
  • the substrate 11a side is the back side
  • the substrate 11b side is the front side.
  • the substrates 11a and 11b face each other.
  • the substrate 11a has light transparency and is typically colorless and / or transparent.
  • the seal layer has a frame shape and is interposed between the substrates 11a and 11b.
  • the substrates 11a and 11b and the sealing layer constitute a cell having a hollow structure.
  • a spacer may be arranged to improve the uniformity of the distance between the substrates 11a and 11b.
  • the electrodes 12a and 12b are located between the substrate 11a and the substrate 11b.
  • the electrodes 12a and 12b are supported by the substrates 11a and 11b, respectively.
  • the electrodes 12a and 12b are light transmissive and are typically colorless and / or transparent.
  • the optically variable layer 13 includes a material having dielectric anisotropy and a solvatochromic dye. Specifically, the optical variable layer 13 includes a dye layer 13SD and a liquid crystal layer 13LC.
  • the dye layer 13SD covers the electrode 12a.
  • the dye layer 13SD includes a solvatochromic dye SD immobilized on the electrode 12a.
  • the solvatochromic dye SD exhibits negative solvatochromism.
  • the solvatochromic dye SD is oriented so that the dipole moment in the ground state or the excited state faces one direction parallel to the surface of the substrate 11a facing the substrate 11b. To do.
  • this direction is referred to as “the orientation direction of the dye molecule SD”.
  • An insulating layer may be interposed between the dye layer 13SD and the electrode 12a.
  • the dye layer 13SD may include an insulating layer and a solvatochromic dye SD fixed thereto.
  • the liquid crystal layer 13LC is interposed between the dye layer 13SD and the electrode 12b.
  • the liquid crystal layer 13LC is made of a liquid crystal material that fills a sealed space surrounded by the substrates 11a and 11b and the seal layer.
  • the liquid crystal material is a nematic liquid crystal having a positive dielectric anisotropy, and the major axis or the dipole moment of the liquid crystal molecules LC is substantially parallel to the alignment direction of the dye when no voltage is applied. Is oriented.
  • the direction of the long axis or dipole moment of the liquid crystal molecules LC is referred to as “the alignment direction of the liquid crystal molecules LC”.
  • the liquid crystal material can be aligned by, for example, providing an alignment film adjacent to the liquid crystal layer 13LC or performing an alignment process on a layer adjacent to the liquid crystal layer 13LC.
  • a rubbing process or a photo-alignment technique can be used for the formation of the alignment film or the alignment process.
  • the reflective layer is installed on the back side of the substrate 11a.
  • the reflective layer may be disposed between the substrate 11a and the dye layer 13SD.
  • a light reflective electrode such as a metal layer or an alloy layer may be used as the electrode 12a.
  • the electrodes 12 a and 12 b of the optical element 10 are connected to the drive circuit 20.
  • the drive circuit includes a variable voltage source.
  • the variable voltage source may be an AC voltage source or a DC voltage source.
  • the combination of the optical element 10 and the drive circuit 20 can be used as a display device, for example.
  • the white light passes through the substrate 11b, the electrode 12b, and the liquid crystal layer 13LC in this order, and enters the dye layer 13SD.
  • the dye layer 13SD absorbs part of the incident light and transmits the other part.
  • the light that has passed through the dye layer 13SD passes through the substrate 11a and is reflected by the reflective layer. This reflected light passes through the substrate 11a and enters the dye layer 13SD.
  • the dye layer 13SD absorbs part of the incident light and transmits the other part.
  • the light that has passed through the dye layer 13SD passes through the liquid crystal layer 13LC, the electrode 12b, and the substrate 11b in this order.
  • the observer perceives this transmitted light as display light. That is, the observer perceives the complementary color of the light color absorbed by the dye layer 13SD.
  • the alignment direction of the liquid crystal molecules LC is parallel to the alignment direction of the dye molecules SD.
  • This state corresponds to the alignment state A1 described with reference to FIGS.
  • the dye layer 13SD absorbs blue light, for example. In this case, the observer perceives yellow, which is a complementary color of blue.
  • the liquid crystal molecules LC are aligned substantially perpendicular to the main surface of the substrate 11a, that is, substantially perpendicular to the display surface, as shown in FIG.
  • This state corresponds to the alignment state A2 described with reference to FIGS.
  • the dye layer 13SD absorbs red light, for example. In this case, the observer perceives a cyan color that is a complementary color of red.
  • the absorption wavelength region of the dye layer 13SD shifts in the short wavelength direction when the voltage applied between the electrodes 12a and 12b is increased. Therefore, in this case, for example, the dye layer 13SD may be designed to absorb red light when no voltage is applied to the electrodes 12a and 12b.
  • the absorption wavelength region when no voltage is applied, and the shift direction and shift amount of the absorption wavelength region accompanying an increase in applied voltage can be controlled by, for example, the liquid crystal material and solvatochromic dye material used and the magnitude of the voltage.
  • both the electrodes 12a and 12b are supported on the substrate 11a.
  • FIG. 10 is a perspective view schematically showing that the optical element according to the second aspect of the present invention displays yellow.
  • FIG. 11 is a perspective view schematically showing how the optical element shown in FIG. 10 displays a magenta color.
  • FIG. 12 is a perspective view schematically showing that the optical element shown in FIG. 10 displays a cyan color.
  • FIG. 13 is a diagram schematically showing solvatochromic dye molecules and liquid crystal molecules in the state shown in FIG.
  • FIG. 14 is a diagram schematically showing solvatochromic dye molecules and liquid crystal molecules in the state shown in FIG.
  • FIG. 15 is a diagram schematically showing solvatochromic dye molecules and liquid crystal molecules in the state shown in FIG. 13 to 15 depict the arrangement of solvatochromic dye molecules and liquid crystal molecules observed from a direction perpendicular to the display surface.
  • the optical element 10 shown in FIGS. 10 to 12 has the same configuration as the optical element 10 described with reference to FIGS. 7 to 9 except that the following configuration is adopted.
  • both the electrodes 12 a and 12 b are located between the substrate 11 a and the optical variable layer 13.
  • the electrodes 12a and 12b each have a shape extending in one direction, and are arranged so that their length directions are parallel to each other.
  • the orientation direction of the solvatochromic dye molecule SD is substantially parallel to the length direction of the electrodes 12a and 12b.
  • the alignment direction of the liquid crystal molecules LC when no voltage is applied is also substantially parallel to the length direction of the electrodes 12a and 12b.
  • the liquid crystal molecules LC are substantially parallel to the display surface and tilted with respect to the length direction of the electrodes 12a and 12b, as shown in FIGS. Oriented in the direction
  • This state is equivalent to the state described with reference to FIG. Therefore, in this case, the observer perceives, for example, a magenta color that is a complementary color of green.
  • the liquid crystal molecules LC are substantially parallel to the display surface and substantially in the length direction of the electrodes 12a and 12b, as shown in FIGS. Orient in the vertical direction.
  • This state is equivalent to the state described with reference to FIG. Therefore, in this case, the observer perceives, for example, a cyan color that is a complementary color of red.
  • the solvatochromic dye is not fixed but mixed with the liquid crystal material.
  • FIG. 16 is a cross-sectional view schematically showing that the optical element according to the third aspect of the present invention displays a certain color.
  • FIG. 17 is a cross-sectional view schematically showing how the optical element shown in FIG. 16 displays other colors.
  • Reference numerals 15 and 16 denote the sealing layer and the reflective layer 16 described above, respectively.
  • the optical element 10 shown in FIGS. 16 and 17 has the same configuration as the optical element 10 described with reference to FIGS. 7 to 9 except that the following configuration is adopted.
  • the optical variable layer 13 has a single layer structure.
  • the optically variable layer 13 is made of a mixture containing a solvatochromic dye and a liquid crystal material.
  • the electrodes 12a and 12b are covered with insulating layers 17a and 17b, respectively.
  • the direction of the dipole moment of the liquid crystal molecules LC is random, or the liquid crystal material is aligned with a low degree of alignment order.
  • the direction of the dipole moment of the solvatochromic dye SD is random, or the solvatochromic dye SD is oriented with a low degree of orientation order.
  • the direction of the dipole moment of the liquid crystal molecules LC and the direction of the dipole moment of the solvatochromic dye SD are random in the state where no voltage is applied.
  • the solvatochromic dye molecule SD is placed in an average dielectric constant environment of the liquid crystal material.
  • the liquid crystal molecules LC are aligned substantially perpendicular to the display surface.
  • the degree of orientation order of the solvatochromic dye SD also increases.
  • the color of the solvatochromic dye SD changes. That is, the display color, particularly the hue, changes.
  • a solvatochromic dye SD having a negative solvatochromism such as a Reichardt dye
  • the absorption spectrum of the optical variable layer 13 is Shift to short wavelength direction.
  • a solvatochromic dye SD having a positive solvatochromism such as Phenol Blue dye
  • the absorption spectrum of the optical variable layer 13 is increased by increasing the voltage applied between the electrodes 12a and 12b. Shifts in the long wavelength direction.
  • the display color can be changed according to the magnitude of the voltage applied between the electrodes 12a and 12b.
  • the optical element 10 since the solvatochromic dye and the liquid crystal material are mixed, it is not necessary to form the dye layer 13SD. Therefore, the optical element 10 is easier to manufacture than the optical element 10 described with reference to FIGS.
  • the mixture containing the solvatochromic dye and the liquid crystal material may be microencapsulated. That is, the optical variable layer 13 may be configured using a microcapsule including the mixture and a transparent film containing the mixture.
  • both the electrodes 12a and 12b may be supported by the substrate 11a.
  • the solvatochromic dye is fixed without being oriented or with a low degree of orientation order.
  • FIG. 18 is a cross-sectional view schematically showing that the optical element according to the fourth aspect of the present invention displays a certain color.
  • FIG. 19 is a cross-sectional view schematically showing how the optical element shown in FIG. 18 displays other colors. 18 and 19 show only a part of the optical variable layer 13 in the optical element 10. Further, FIG. 18 illustrates a state in which no voltage is applied, and FIG. 19 illustrates a state in which a sufficiently large voltage is applied.
  • the optical element 10 shown in FIGS. 18 and 19 has the same configuration as the optical element 10 described with reference to FIGS. 7 to 9 except that the following configuration is adopted.
  • the optically variable layer 13 further includes a porous body 13P in addition to the solvatochromic dye SD and the liquid crystal material.
  • the porous body 13P forms a layer sandwiched between the electrodes 12a and 12b.
  • the solvatochromic dye SD is immobilized on the wall surfaces of the pores of the porous body 13P.
  • the optical variable layer 13 displays the same color as described with reference to FIG. 7, for example.
  • the liquid crystal molecules LC are aligned in approximately one direction as shown in FIG. Accordingly, the average angle formed by the dipole moment of the liquid crystal molecules LC and the dipole moment of the solvatochromic dye SD located in the vicinity thereof increases. As a result, the color of the solvatochromic dye SD changes. That is, the display color, particularly the hue, changes.
  • the display color can be changed according to the magnitude of the voltage applied between the electrodes 12a and 12b.
  • the area of the porous body 13P is much larger than that of the electrode 12a. Therefore, when the porous body 13P is used, more solvatochromic dye SD can be immobilized. Therefore, a higher color density can be achieved.
  • both the electrodes 12a and 12b may be supported by the substrate 11a.
  • the substrates 11a and 11b for example, those having sufficient strength and insulation are used.
  • the substrate 11a a substrate having optical transparency, typically a transparent substrate, is used.
  • substrate 11b may have a light transmittance and does not need to have it.
  • a material of the substrates 11a and 11b for example, glass, plastic, ceramic and metal can be used.
  • the electrode installed between the optically variable layer 13 and the observer has light transparency and is typically transparent.
  • a transparent conductive material such as indium tin oxide (ITO) can be used.
  • ITO indium tin oxide
  • a metal such as aluminum, nickel, copper, silver, gold and platinum or an alloy thereof can be used.
  • the electrodes 12a and 12b may have a single layer structure or a multilayer structure.
  • the electrodes 12a and 12b are obtained, for example, by performing film formation by a vapor deposition method such as vapor deposition and sputtering, and performing patterning using, for example, photolithography as necessary.
  • an adhesive can be used.
  • a spacer is provided between the substrates 11a and 11b, for example, a granular spacer or a columnar spacer similar to that used in a liquid crystal display device can be used.
  • the granular spacer and the columnar spacer are electrically insulating.
  • the material of the granular spacer for example, polymers such as divinylbenzene and polystyrene, or inorganic oxides such as alumina and silica can be used.
  • a positive or negative photosensitive resin that can use photolithography can be used.
  • a photosensitive resin containing polyimide, polyamide, polyvinyl alcohol, polyacrylamide, cyclized rubber, novolac resin, polyester, polyurethane, acrylic resin, bisphenol resin, or gelatin can be used.
  • the surface of at least one of the electrodes 12a and 12b may be covered with an insulating layer.
  • the material for the insulating layer include polyimide, polyamide, polyvinyl alcohol, polyacrylamide, cyclized rubber, novolac resin, polyester, polyurethane, acrylic resin, bisphenol resin, gelatin, and other organic substances, or silicon oxide and silicon nitride. Inorganic materials can be used.
  • the insulating layer may have a single layer structure or a multilayer structure.
  • the insulating layer can be formed, for example, by a coating method such as spin coating, a Langmuir-Blodgett method in which a monomolecular film formed on the water surface is copied onto an electrode, or a vapor deposition method such as a vapor deposition method.
  • the insulating layer may be subjected to an alignment treatment such as a rubbing treatment in order to control the alignment of a material having dielectric anisotropy such as a liquid crystal material.
  • a material having dielectric anisotropy is a material having dielectric anisotropy in the molecule, that is, a material having anisotropy in the molecule such as orientation polarization, electronic polarization and atomic polarization. .
  • the material having dielectric anisotropy may be an organic material or an inorganic material.
  • a liquid crystal material As a material having dielectric anisotropy, for example, a liquid crystal material can be used.
  • the liquid crystal material may be a liquid crystal compound or a composition containing a plurality of liquid crystal compounds.
  • the liquid crystal material may be a composition containing one or more liquid crystal compounds and one or more other compounds.
  • liquid crystal material examples include a nematic liquid crystal material, a cholesteric liquid crystal material, or a chiral nematic liquid crystal material (hereinafter referred to as a cholesteric liquid crystal material and / or a chiral nematic liquid crystal material), a nematic liquid crystal material and a cholesteric liquid crystal material, or A mixture with a chiral agent or a smectic liquid crystal material can be used.
  • the material having dielectric anisotropy may be composed only of components having dielectric anisotropy, or may further include a material having no dielectric anisotropy.
  • the dielectric anisotropy of the liquid crystal material preferably has a large absolute value.
  • the absolute value of dielectric anisotropy which is the value obtained by subtracting the relative dielectric constant in the minor axis direction from the relative dielectric constant in the major axis direction of the liquid crystal molecules Is preferably 5 or more, more preferably 10 or more.
  • solvatochromic dye a compound showing solvatochromism or a composition containing a plurality of compounds showing solvatochromism can be used.
  • Examples of the compound exhibiting solvatochromism include Chem. Rev. , 94, 2319 (1994) can be used.
  • the solvatochromic dye preferably has a large absorption wavelength shift amount corresponding to the change in the polarity of the solvent, such as one having an intramolecular charge transfer structure. Further, from the viewpoint of color density, the solvatochromic dye is desirably an organic material having a large absorbance. Examples of such solvatochromic dyes include Reichardt dyes.
  • the solvatochromic dye may be immobilized on an organic material or an inorganic material.
  • the solvatochromic dye may be incorporated in the main chain or side chain of the polymer material supported by the electrode 12a or 12b. As described above, the solvatochromic dye is preferably immobilized on the porous body.
  • an alignment film When aligning a solvatochromic dye, for example, an alignment film can be used. For example, by applying a liquid containing a solvatochromic dye on the alignment film and drying the coating film, the solvatochromic dye can be oriented and fixed. Alternatively, when the solvatochromic dye is incorporated in the main chain or side chain of the polymer material, a layer containing the polymer material is formed, and the layer is subjected to stretching treatment or rubbing treatment, thereby The chromic dye can be oriented.
  • the absorption axis of the solvatochromic dye is preferably substantially perpendicular to the display surface. In this case, more efficient light absorption by the solvatochromic dye material can be realized.
  • the direction of the dipole moment in the ground state or excited state of the solvatochromic dye is, for example, parallel to the alignment direction in which the alignment film aligns the liquid crystal material, and between the electrodes 12a and 12b. It is perpendicular to the direction of the electric field generated when a voltage is applied to.
  • the direction of the dipole moment in the ground state or excited state of the solvatochromic dye is perpendicular to the alignment direction in which the alignment film aligns the liquid crystal material, and an electric field generated when a voltage is applied between the electrodes 12a and 12b. Parallel to the direction.
  • the change in the absorption wavelength accompanying the change in the applied voltage can be maximized.
  • parallel means that the angle formed by the two directions is within a range of ⁇ 20 ° to + 20 °.
  • “Vertical” means that the angle formed by the two directions is in the range of + 70 ° to + 110 °.
  • the material of the reflective layer 16 a metal such as aluminum and silver or an alloy thereof can be used.
  • the reflective layer 16 can be omitted, for example, when the electrode 12a also serves as the reflective layer or when the optical element 10 is a transmissive type.
  • the color to be displayed on the optical element 10 can be controlled by the magnitude of the driving voltage.
  • the drive circuit 20 outputs an alternating voltage as a drive voltage
  • the color to be displayed on the optical element 10 can be controlled by at least one of the magnitude and frequency of the drive voltage.
  • AC driving instead of DC driving.
  • the frequency is preferably set in a range of 10 Hz to 1 KHz, more preferably 30 Hz to 240 Hz, from the viewpoint of flicker phenomenon suppression and low power consumption. Set within the range.
  • the drive circuit 20 can change the absorption maximum wavelength over almost the entire visible light range, for example.
  • the drive circuit 20 preferably has the maximum absorption maximum wavelength.
  • the operation of the optical element 10 is controlled so that the absorption maximum wavelength changes at a maximum of 250 nm or more so as to change by 100 nm or more.
  • the “visible light region” means a wavelength region of 400 nm to 800 nm.
  • Example 1 the optical element 10 described with reference to FIGS. 16 and 17 was manufactured by the following method.
  • Two transparent non-alkali glass substrates 11a and 11b provided with ITO electrodes 12a and 12b were prepared.
  • the thickness of each glass substrate was 0.7 mm.
  • an insulating layer 17a was formed on the electrode 12a by casting polyimide to a thickness of 70 nm using a spinner.
  • polyimide AL-1051 manufactured by Nippon Synthetic Rubber Company was used.
  • the epoxy adhesive used as the sealing layer 15 was dispensed to the peripheral part of the said main surface of the board
  • the insulating layer 17b was also formed on the electrode 12b by the same method as described for the insulating layer 17a. Resin spacer balls having a diameter of 10 ⁇ m were sprayed on the insulating layer 17b.
  • a mixture containing 96 parts by mass of a nematic liquid crystal material and 4 parts by mass of a solvatochromic dye was vacuum-injected into an empty cell in an isotropic phase to form the optically variable layer 13.
  • a nematic liquid crystal material 4-cyano-4'-pentylbiphenyl manufactured by Aldrich-Sigma was used.
  • solvatochromic dye Reichardt dye manufactured by Aldrich-Sigma was used.
  • the reflective film 16 was pasted on the substrate 11a. As described above, the optical element 10 shown in FIGS. 16 and 17 was completed.
  • the optical element 10 was connected to the drive circuit 20. And the alternating voltage was applied between the electrodes 12a and 12b, and the color change accompanying a voltage change was observed. In addition, the waveform of this alternating voltage was a rectangular wave, and the frequency was 30 Hz. The results are shown in FIG.
  • FIG. 20 is a graph showing an example of a color change accompanying a voltage change.
  • the horizontal axis indicates the wavelength
  • the vertical axis indicates the absorbance (arbitrary unit).
  • This optical element 10 displayed green in the state of no voltage application (0 V), and the absorption maximum wavelength at this time was 680 nm as shown in FIG.
  • the optical element 10 displayed red when the applied voltage was 20 V, and the absorption maximum wavelength at this time was 580 nm as shown in FIG.
  • Example 2 In this example, the optical element 10 described with reference to FIGS. 16 and 17 was manufactured by the following method. First, an empty cell was formed by the same method as described in Example 1.
  • a mixture containing 96 parts by mass of a nematic liquid crystal material and 4 parts by mass of a solvatochromic dye was vacuum-injected into an empty cell in an isotropic phase to form the optically variable layer 13.
  • a nematic liquid crystal material ZLI-4900-000 manufactured by Merck & Co. was used.
  • solvatochromic dye Reichardt dye manufactured by Aldrich-Sigma was used.
  • the reflective film 16 was pasted on the substrate 11a. As described above, the optical element 10 shown in FIGS. 16 and 17 was completed.
  • the optical element 10 was connected to the drive circuit 20. And the alternating voltage was applied between the electrodes 12a and 12b, and the color change accompanying a voltage change was observed. In addition, the waveform of this alternating voltage was a rectangular wave, and the frequency was 30 Hz.
  • this optical element 10 displayed a light orange color when no voltage was applied (0 V), and displayed a reddish purple color when the applied voltage was 15 V.
  • FIG. 21 is a cross-sectional view schematically showing an optical element according to Example 3.
  • the optical element 10 shown in FIG. 21 was manufactured by the following method.
  • Two transparent non-alkali glass substrates 11a and 11b provided with ITO electrodes 12a and 12b were prepared.
  • the thickness of each glass substrate was 0.7 mm.
  • the electrode 12a was rubbed.
  • a solution containing a solvatochromic dye was cast on the electrode 12a to a thickness of 50 nm with a spinner. Thereby, a dye layer 13SD was obtained.
  • the solvatochromic dye Reichardt dye manufactured by Aldrich-Sigma was used.
  • the epoxy adhesive used as the sealing layer 15 was dispensed to the peripheral part of the said main surface of the board
  • polyimide was cast to a thickness of 70 nm by a spinner, and the coating film was rubbed to form an insulating layer 17b.
  • the polyimide AL-1051 manufactured by Nippon Synthetic Rubber Company was used. Then, resin spacer balls having a diameter of 10 ⁇ m were dispersed on the insulating layer 17b.
  • the substrates 11a and 11b were bonded so that the insulating layers 17a and 17b face each other and the rubbing directions were parallel, and the epoxy adhesive was cured. Thereby, an empty cell was obtained.
  • nematic liquid crystal material JC-1041 manufactured by Chisso Corporation was used.
  • the reflective film 16 was pasted on the substrate 11a. As described above, the optical element 10 shown in FIG. 21 was completed.
  • the optical element 10 was connected to the drive circuit 20. And the alternating voltage of 30V was applied between the electrodes 12a and 12b, and the color change accompanying a voltage change was observed. In addition, the waveform of this alternating voltage was a rectangular wave, and the frequency was 30 Hz. The results are shown in FIG.
  • FIG. 22 is a graph showing another example of color change accompanying voltage change.
  • the horizontal axis indicates the wavelength
  • the vertical axis indicates the absorbance (arbitrary unit).
  • a curve C OFF shows an absorption spectrum in a state where no voltage is applied. Curves C ON (0), C ON (30), and C ON (90) are respectively applied immediately after the voltage is applied, after 30 seconds from the start of the voltage application, and after the voltage application is started. An absorption spectrum after 90 seconds has been shown.
  • the optical element 10 shown in FIG. 21 was manufactured by the following method. Two transparent non-alkali glass substrates 11a and 11b provided with ITO electrodes 12a and 12b, respectively, were prepared. The thickness of each glass substrate was 0.7 mm.
  • the electrode 12a was rubbed.
  • a liquid containing a polymer having a solvatochromic dye in the side chain was cast on the electrode 12a with a spinner to a thickness of 30 nm. Further, the coating layer was rubbed to obtain a dye layer 13SD.
  • this polymer a compound represented by the following chemical formula was used. Then, the epoxy adhesive used as the sealing layer 15 was dispensed to the peripheral part of the said main surface of the board
  • polyimide was cast to a thickness of 70 nm by a spinner, and the coating film was rubbed to form an insulating layer 17b.
  • the polyimide AL-1051 manufactured by Nippon Synthetic Rubber Company was used. Then, resin spacer balls having a diameter of 10 ⁇ m were dispersed on the insulating layer 17b.
  • the substrates 11a and 11b were bonded so that the insulating layers 17a and 17b face each other and the rubbing directions were parallel, and the epoxy adhesive was cured. Thereby, an empty cell was obtained.
  • nematic liquid crystal material manufactured by Merck was vacuum-injected into an empty cell in a liquid crystal phase to form a liquid crystal layer 13LC.
  • a nematic liquid crystal material having a dielectric anisotropy ⁇ of 20 and a refractive index anisotropy ⁇ n of 0.15 was used.
  • the reflective film 16 was pasted on the substrate 11a. As described above, the optical element 10 shown in FIG. 21 was completed.
  • the optical element 10 was connected to the drive circuit 20. And the alternating voltage was applied between the electrodes 12a and 12b, and the color change accompanying a voltage change was observed. In addition, the waveform of this alternating voltage was a rectangular wave, and the frequency was 30 Hz.
  • the optical element 10 displayed red when no voltage was applied (0 V), and displayed green when the applied voltage was 15 V.
  • Example 5 the optical element described with reference to FIGS. 18 and 19 was manufactured by the following method.
  • porous glass beads 13P having a thickness of 3 ⁇ m and a pore diameter of 1 ⁇ m were prepared by heat treatment of borosilicate soda glass and subsequent acid treatment.
  • the porous glass beads were impregnated with an ethanol solution of Reichardt dye to immobilize the Reichardt dye on the walls of the pores.
  • the particles thus obtained were encapsulated in a cell composed of two transparent glass substrates provided with ITO electrodes on the surface thereof and a sealing layer.
  • a non-alkali glass substrate having a thickness of 0.7 mm was used as the glass substrate.
  • nematic liquid crystal material manufactured by Merck was vacuum-injected into the cell in an isotropic phase.
  • a nematic liquid crystal material having a dielectric anisotropy ⁇ of 15 and a refractive index anisotropy ⁇ n of 0.18 was used.
  • the reflective film 16 was pasted on one substrate. As described above, the optical element described with reference to FIGS. 18 and 19 was completed.
  • the optical element 10 was connected to the drive circuit 20. And the alternating voltage was applied between the electrodes 12a and 12b, and the color change accompanying a voltage change was observed. In addition, the waveform of this alternating voltage was a rectangular wave, and the frequency was 30 Hz.
  • this optical element 10 displayed reddish purple when no voltage was applied (0 V), and displayed yellowish green when the applied voltage was 50 V.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)

Abstract

La présente invention porte sur une technique par laquelle une image multicolore peut être affichée avec une excellente reproductibilité de couleur. Un élément optique (10) comprend une couche variable optiquement (13) contenant un matériau anisotrope diélectriquement (LC) d'un colorant solvatochromique (SD), et des électrodes (12a, 12b) pour appliquer une tension sur la couche variable optiquement (13).
PCT/JP2009/069577 2008-11-19 2009-11-18 Élément optique et dispositif d'affichage WO2010058799A1 (fr)

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JP2008295851A JP5238462B2 (ja) 2008-11-19 2008-11-19 光学素子及び表示装置

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Publication number Priority date Publication date Assignee Title
JP2004233655A (ja) * 2003-01-30 2004-08-19 Fuji Photo Film Co Ltd 画像表示素子、画像表示装置及び化合物の製造方法

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JP5103730B2 (ja) 2005-06-03 2012-12-19 富士ゼロックス株式会社 表示方法、並びに、これを用いた表示媒体及び表示素子
JP5034271B2 (ja) 2006-03-06 2012-09-26 富士ゼロックス株式会社 表示媒体の表示方法、及び表示装置
JP2007279163A (ja) 2006-04-03 2007-10-25 Fuji Xerox Co Ltd 表示方法、表示媒体、及び表示素子

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Publication number Priority date Publication date Assignee Title
JP2004233655A (ja) * 2003-01-30 2004-08-19 Fuji Photo Film Co Ltd 画像表示素子、画像表示装置及び化合物の製造方法

Non-Patent Citations (2)

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Title
HIROKI IWANAGA ET AL.: "Oligothiophene dyes for guest-host liquid crystal displays", LIQUID CRYSTALS, vol. 27, no. 1, 2000, pages 115 - 123 *
LARS-OLOF PALSSON ET AL.: "ORIENTATION AND SOLVATOCHROMISM OF DYES IN LIQUID CRYSTAL", MOL. CRYST. LIQ. CRYST., vol. 402, 2003, pages 43(279) - 53(289) *

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