WO2024106236A1 - Dispositif d'affichage et équipement électronique - Google Patents

Dispositif d'affichage et équipement électronique Download PDF

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Publication number
WO2024106236A1
WO2024106236A1 PCT/JP2023/039809 JP2023039809W WO2024106236A1 WO 2024106236 A1 WO2024106236 A1 WO 2024106236A1 JP 2023039809 W JP2023039809 W JP 2023039809W WO 2024106236 A1 WO2024106236 A1 WO 2024106236A1
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Prior art keywords
layer
oxide
display device
reflective electrodes
liquid crystal
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PCT/JP2023/039809
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English (en)
Japanese (ja)
Inventor
慎太郎 中野
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ソニーセミコンダクタソリューションズ株式会社
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Publication of WO2024106236A1 publication Critical patent/WO2024106236A1/fr

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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
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • 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
    • G02F1/1343—Electrodes

Definitions

  • This disclosure relates to a display device used, for example, as a light valve in a projector, and an electronic device equipped with the same.
  • Patent Document 1 discloses a display device in which a transparent conductive film such as IZO or ITO is formed directly on a reflective layer made of Al or the like as a first electrode (pixel electrode), thereby making the work function of the first electrode the same as the work function of the second electrode on the second substrate side.
  • a transparent conductive film such as IZO or ITO is formed directly on a reflective layer made of Al or the like as a first electrode (pixel electrode), thereby making the work function of the first electrode the same as the work function of the second electrode on the second substrate side.
  • the display device of one embodiment of the present disclosure includes a first substrate having a plurality of reflective electrodes provided on each of a plurality of pixels arranged in an array, a second substrate arranged opposite the first substrate and having a common electrode provided across the plurality of pixels, a liquid crystal layer provided between the first substrate and the second substrate, and a laminated film provided on the surface of at least one of the plurality of reflective electrodes and the common electrode facing the liquid crystal layer, the laminated film having a first layer and a second layer having different oxygen densities.
  • An electronic device includes a display device according to one embodiment of the present disclosure.
  • a laminate film having a first layer and a second layer with different oxygen densities is provided on the electrode surface facing the liquid crystal layer of at least one of a plurality of reflective electrodes and a common electrode arranged opposite each other with a liquid crystal layer between them. This eliminates the difference in work function between the plurality of reflective electrodes and the common electrode.
  • FIG. 1 is a schematic cross-sectional view illustrating a configuration of a liquid crystal display panel according to an embodiment of the present disclosure.
  • 2 is a schematic cross-sectional view illustrating an example of a configuration of a work function adjustment layer illustrated in FIG. 1 .
  • 2 is a schematic cross-sectional view illustrating another example of the configuration of the work function adjustment layer illustrated in FIG. 1 .
  • 2 is a schematic cross-sectional view illustrating another example of the configuration of the work function adjustment layer illustrated in FIG. 1 .
  • 2A to 2C are schematic cross-sectional views illustrating an example of a method for manufacturing the reflective electrode and the work function adjusting layer illustrated in FIG. 1 .
  • FIG. 6B is a schematic cross-sectional view showing a step subsequent to FIG. 6A.
  • FIG. 6C is a schematic cross-sectional view showing a step following FIG. 6B.
  • FIG. 6B is a schematic cross-sectional view showing a step following FIG. 6C.
  • FIG. 6B is a schematic cross-sectional view showing a step following FIG. 6D.
  • 1 is a waveform diagram of a signal voltage relative to an ideal common voltage in a liquid crystal display panel.
  • FIG. 2 is a waveform diagram of a signal voltage relative to a common voltage in a general liquid crystal display panel. 2 is a waveform diagram of a signal voltage relative to a common voltage in the liquid crystal display panel shown in FIG. 1.
  • FIG. 11 is a cross-sectional view illustrating a configuration of a liquid crystal display panel according to a first modified example of the present disclosure.
  • FIG. 11 is a schematic cross-sectional view illustrating a configuration of a liquid crystal display panel according to a second modified example of the present disclosure.
  • 13 is a schematic cross-sectional view illustrating an example of the configuration of a work function adjustment layer illustrated in FIG. 12.
  • 13 is a schematic cross-sectional view illustrating another example of the configuration of the work function adjustment layer illustrated in FIG. 12.
  • 11 is a cross-sectional view illustrating a configuration of a liquid crystal display panel according to a third modification of the present disclosure.
  • 1 is a functional block diagram illustrating an overall configuration of a projection display device according to the present disclosure.
  • 17 is a schematic diagram illustrating an example of a configuration of an optical system of the projection display device illustrated in FIG. 16.
  • Embodiment Example of a display device having a work function adjustment layer on a reflective electrode
  • Configuration of liquid crystal display panel 1-2.
  • Actions and effects 2.
  • Modification 3 another example of the configuration of the liquid crystal display panel) 3.
  • Application example projection display device example
  • Preferred embodiment 1 is a schematic diagram showing an example of a cross-sectional configuration of a display device (liquid crystal display panel 1) according to an embodiment of the present disclosure.
  • the liquid crystal display panel 1 is used, for example, as a light valve (e.g., liquid crystal panels 322A, 322B, and 322C, see FIG. 17) of a projection-type display device such as a projector (projection-type display device 5, see FIG. 16) described later.
  • the liquid crystal display panel 1 has a display area in which a plurality of pixels are arranged two-dimensionally in a matrix.
  • the liquid crystal display panel 1 has a liquid crystal layer 30 between a driving substrate 10 and a counter substrate 20 arranged opposite each other, and the driving substrate 10 is provided with a plurality of reflective electrodes 13, for example, one for each pixel, as pixel electrodes.
  • the plurality of reflective electrodes 13 correspond to a specific example of the "plurality of reflective electrodes" of the present disclosure.
  • a work function adjustment layer 14 is formed on the surface of the plurality of reflective electrodes 13 facing the liquid crystal layer 30 (hereinafter simply referred to as on the plurality of reflective electrodes 13), in which a plurality of layers having different oxygen densities are stacked.
  • the driving substrate 10 has, for example, a substrate 11 made of silicon (Si), a pixel circuit layer 12, a plurality of reflective electrodes 13, and an alignment film 15.
  • the pixel circuit layer 12, the plurality of reflective electrodes 13, the work function adjustment layer 14, and the alignment film 15 are provided in this order on the surface of the substrate 11 facing the liquid crystal layer 30.
  • the pixel circuit layer 12 is provided on the substrate 11 and includes, for example, a plurality of transistors that drive the liquid crystal layer 30 for each pixel, a plurality of reflective electrodes 13 provided on the surface of the pixel circuit layer 12, for example, one for each pixel, and work function adjustment layers 14 provided on each of the plurality of reflective electrodes 13, and, for example, a plurality of wiring layers that electrically connect the plurality of transistors and the plurality of reflective electrodes 13, respectively.
  • the pixel circuit layer 12 has, as one of the wiring layers below the plurality of reflective electrodes 13, a wiring layer 122 that includes a light-shielding film 122X that blocks light that has passed between the adjacent plurality of reflective electrodes 13 below the adjacent plurality of reflective electrodes 13.
  • a plurality of reflective electrodes 13 are provided in an array shape in a plan view, for example for each pixel.
  • the wiring layer 122 and the multiple reflective electrodes 13 are each electrically connected via, for example, a plug 123.
  • the wiring layer 122 and a wiring layer (not shown) provided further below are each electrically connected via, for example, a plug, in the same manner as the wiring layer 122 and the multiple reflective electrodes 13.
  • the multiple wiring layers provided on the substrate 11 including the wiring layer 122, the multiple reflective electrodes 13, and the work function adjustment layers 14 provided on each of the multiple reflective electrodes 13 are embedded in the interlayer insulating layer 121, and the work function adjustment layers 14 are exposed on the surface of the interlayer insulating layer 121.
  • the interlayer insulating layer 121 is composed of, for example, silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiO x N y ), SiC x N y , etc.
  • the interlayer insulating layer 121 can be formed by, for example, a CVD method or a coating method using, for example, a spin coater.
  • the wiring layer 122 is provided on the substrate 11, and is one of a number of wiring layers that electrically connects, for example, a number of transistors that drive the liquid crystal layer 30 for each pixel to a number of reflective electrodes 13 provided for each pixel, and is provided directly below the reflective electrodes 13.
  • the wiring layer 122 also has a light-shielding film 122X below the gap between the adjacent reflective electrodes 13 that blocks light that has passed between the adjacent reflective electrodes 13.
  • the wiring layer 122 is made of a metal material that has light reflectivity and is mainly made of a low-resistance metal, such as aluminum (Al), titanium (Ti), copper (Cu), or an alloy thereof.
  • a barrier metal may be provided on each of the upper and lower surfaces of the wiring layer 122.
  • the barrier metal may be, for example, a single film of Ti (titanium) or Ta (tantalum), or a laminated film of, for example, titanium (Ti) and titanium nitride (TiN).
  • the plugs 123 that electrically connect the wiring layer 122 and the multiple reflective electrodes 13 are made of, for example, tungsten (W).
  • the multiple reflective electrodes 13 are made of a metal material that is light reflective and mainly made of a low-resistance metal, such as aluminum (Al), titanium (Ti), copper (Cu), silicon (Si), silver (Ag), or an alloy thereof (e.g., an Al-Cu alloy or an Al-Si alloy).
  • the multiple reflective electrodes 13 have, for example, a substantially rectangular shape, and are arranged, for example, in a matrix in the display area.
  • the film thickness (hereinafter simply referred to as thickness) of the multiple first electrode layers 131 in the stacking direction (Y-axis direction) is, for example, 50 nm or more and 2000 nm or less.
  • the work function adjustment layer 14 corresponds to one specific example of the "laminated film" of the present disclosure, and as described above, is provided on each of the multiple reflective electrodes 13.
  • the work function adjustment layer 14 changes the apparent work function of each of the multiple reflective electrodes 13 by forming an interface dipole on the multiple reflective electrodes 13.
  • the work function adjustment layer 14 is a laminated film in which multiple layers (first layer 141 and second layer 142) with different oxygen densities are stacked. When films with different oxygen densities are stacked, oxygen moves from the one with the higher oxygen density to the one with the lower oxygen density. This causes a charge transfer due to the generation of oxygen vacancies, and the work function shifts.
  • the variation in work function due to the difference in oxygen density between the first layer 141 and the second layer 142 is greater than 0 eV and less than or equal to 1 eV, and preferably greater than 0 eV and less than or equal to 0.5 eV, for example.
  • the work function of the multiple reflective electrodes 13 made of aluminum with respect to the counter electrode 22 made of indium tin oxide (ITO) varies depending on the crystal orientation.
  • the crystal plane of Al(100) has a work function of 4.20 eV.
  • the crystal plane of Al(110) has a work function of 4.06 eV.
  • the crystal plane of Al(111) has a work function of 4.26 eV.
  • the counter electrode 22 made of ITO has a work function of about 4.1 eV.
  • the first layer 141 is made of, for example, a silicon oxide (SiO x ) film.
  • the thickness of the first layer 141 is, for example, not less than 0 nm and not more than 100 nm, and preferably, for example, not less than 0 nm and not more than 50 nm.
  • the second layer 142 is made of a high dielectric constant film having a higher dielectric constant than the first layer 141.
  • materials constituting the second layer 142 include aluminum oxide (AlO x ), tantalum oxide (TaO x ), titanium oxide (TiO x ), zirconium oxide (ZrO x ), hafnium oxide (HfO x ), scandium oxide (ScO x ), magnesium oxide (MgO x ), yttrium oxide (YO x ), lanthanum oxide (LaO x ), lutetium oxide (LuO x ), and strontium oxide (SrO x ).
  • the thickness of the second layer 142 is, for example, 0 nm or more and 100 nm or less, and preferably , for example, 0 nm or more and 50 nm or less.
  • the work function adjustment layer 14 may be laminated in the order of a first layer 141 and a second layer 142 on the reflective electrode 13 as shown in Figures 2 and 3, or may be laminated in the order of a second layer 142 and a first layer 141 on the reflective electrode 13 as shown in Figures 4 and 5.
  • the constituent material of the second layer 142 relative to the first layer 141 made of a SiO x film, and the stacking order of the first layer 141 and the second layer 142 are appropriately selected depending on the work function difference between the plurality of reflective electrodes 13 and the counter electrode 22 .
  • the work function of the plurality of reflective electrodes 13 is larger than that of the counter electrode 22 (the plurality of reflective electrodes 13>the counter electrode 22), it is desired to shift the plurality of reflective electrodes 13 in the negative direction.
  • the first layer 141 and the second layer 142 are laminated in this order on the reflective electrode 13, the first layer 141 side is made positive (+) and the second layer 142 side is made negative (-) as shown in FIG. 2.
  • the second layer 142 can be formed using YO x , LaO x , LuO x or SrO x among the above-mentioned constituent materials.
  • the second layer 142 and the first layer 141 are laminated in this order on the reflective electrode 13
  • the first layer 141 side is made negative (-) and the second layer 142 side is made positive (+) as shown in FIG. 4.
  • the second layer 142 can be formed using AlOx , TaOx , TiOx , ZrOx , HfOx , ScOx , or MgOx among the above-mentioned constituent materials.
  • the work function of the plurality of reflective electrodes 13 is smaller than that of the counter electrode 22 (the plurality of reflective electrodes 13 ⁇ the counter electrode 22), it is desired to shift the plurality of reflective electrodes 13 side in the positive direction.
  • the first layer 141 and the second layer 142 are laminated in this order on the reflective electrode 13, the first layer 141 side is made negative (-) and the second layer 142 side is made positive (+) as shown in FIG. 3.
  • the second layer 142 can be formed using AlO x , TaO x , TiO x , ZrO x , HfO x , ScO x or MgO x among the above-mentioned constituent materials.
  • the second layer 142 and the first layer 141 are laminated in this order on the reflective electrode 13
  • the first layer 141 side is made positive (+) and the second layer 142 side is made negative (-) as shown in FIG. 5.
  • the second layer 142 can be formed using YOx , LaOx , LuOx , or SrOx among the above-mentioned constituent materials.
  • the reflectance of the light reflecting surface of the plurality of reflective electrodes 13 is improved by the interference between the SiO x film (refractive index 1.46) and the LaO x film (refractive index 1.88).
  • a third layer 143 is preferably formed on the surface of the work function adjustment layer 14.
  • the third layer 143 is used as a stopper film in a chemical mechanical polishing (CMP) step for planarizing the surface on the drive substrate 10 side in a manufacturing method of a pixel electrode described later.
  • CMP chemical mechanical polishing
  • the third layer 143 can be formed using, for example, silicon nitride (SiN x ).
  • the alignment film 15 controls the alignment of the liquid crystal layer 30, and is made of an inorganic material such as silicon oxide ( SiO2 ), diamond-like carbon, or aluminum oxide ( Al2O3 ).
  • the thickness of the alignment film 15 is, for example, 50 nm or more and 500 nm or less.
  • the alignment film 15 can be formed by using, for example, a vapor deposition method.
  • the counter substrate 20 has, for example, a light-transmitting substrate 21, a counter electrode 22, an alignment film 23, and a polarizing plate 24.
  • the counter electrode 22 and the alignment film 23 are provided in this order on the surface of the substrate 21 facing the liquid crystal layer 30, and the polarizing plate 24 is provided on the surface of the substrate 21 opposite the liquid crystal layer 30.
  • the counter electrode 22 is provided across the entire display area 100A, for example, as a common electrode for all pixels.
  • the counter electrode 22 is made of, for example, a light-transmitting conductive material.
  • Examples of light-transmitting conductive materials include indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and indium gallium zinc oxide (IGZO).
  • the alignment film 23 controls the alignment of the liquid crystal layer 30, and is made of an inorganic material such as silicon oxide ( SiO2 ), diamond-like carbon, or aluminum oxide ( Al2O3 ).
  • the thickness of the alignment film 23 is, for example, 50 nm or more and 500 nm or less.
  • the alignment film 15 can be formed by using, for example, a vapor deposition method.
  • the polarizing plates 24 are arranged, for example, in a crossed Nicol configuration, so that only light (polarized light) with a specific vibration direction can pass through the polarizing plates.
  • Each polarizing plate is made of, for example, polyvinyl alcohol (PVA) with iodine (I) compound molecules adsorbed and aligned.
  • the liquid crystal layer 30 is composed of liquid crystals driven in, for example, VA (Vertical Alignment) mode, TN (Twisted Nematic) mode, ECB (Electrically Controlled Birefringence) mode, FFS (Fringe Field Switching) mode, or IPS (In Plane Switching) mode.
  • the liquid crystal layer 30 is sealed by, for example, a thermosetting or UV-curing sealant that is commercially available for liquid crystal displays, which bonds the drive substrate 10 and the counter substrate 20 together.
  • the liquid crystal layer 30 is formed by bonding the drive substrate 10 and the counter substrate 20 together using a sealant, injecting liquid crystal, and sealing the liquid crystal layer 30 with, for example, a UV-curing sealant.
  • the liquid crystal layer 30 may be manufactured using, for example, an ODF (One Drop Fill) process.
  • a video voltage is supplied to the liquid crystal layer 30 by a plurality of reflective electrodes 13 and a counter electrode 22.
  • FIGS. 6A to 6E are schematic diagrams showing the cross-sectional configuration on the driving substrate 10 side in each process.
  • an interlayer insulating layer 121 is formed in which a wiring layer 122 and plugs 123 are embedded, and the surface is planarized by, for example, CMP.
  • the reflective electrode 13, the first layer 141, the second layer 142, and the third layer 143 are deposited in this order on the interlayer insulating layer 121, for example, by using a CVD method.
  • the reflective electrode 13, the first layer 141, the second layer 142, and the third layer 143 are patterned by processing using, for example, lithography technology and dry processing (or wet processing).
  • the interlayer insulating layer 121 is further formed, and the reflective electrode 13, the first layer 141, the second layer 142, and the third layer 143 are embedded.
  • the interlayer insulating layer 121 is ground by CMP until the third layer 143 is exposed, and the surface is flattened. As a result, the multiple reflective electrodes 13 and the work function adjustment layers 14 provided on each of the multiple reflective electrodes 13 shown in FIG. 1 are formed.
  • the second layer 142 and the first layer 141 are formed in this order on the reflective electrode 13 and the second layer 142 is formed using AlOx
  • the second layer 142 can be formed by oxidizing the reflective electrode 13.
  • the oxidation method it is preferable to select, for example, anodization, plasma oxidation, or ozone oxidation. This allows the surface of the reflective electrode 13 to be uniformly oxidized.
  • the liquid crystal display panel 1 of the present embodiment is provided with a work function adjustment layer 14 having a first layer 141 and a second layer 142 having different oxygen densities on a plurality of reflective electrodes 13. This adjusts the work function difference between the plurality of reflective electrodes 13 and the counter electrode 22. This will be described below.
  • a reflective LCD device In a reflective LCD device, the electrodes that apply voltage to the liquid crystal are made of different materials on the opposing substrate and the driving substrate, resulting in a difference in work function.
  • impurity ions contained in the liquid crystal move to the alignment film on the opposing substrate or driving substrate due to the electric field during operation, causing problems such as flicker and burn-in.
  • a typical reflective LCD device applies a voltage (signal voltage Vsig) whose polarity is inverted with respect to the common voltage Vcom to the liquid crystal every frame, as shown in Figure 7, so that the impurity ions are not concentrated on the opposing substrate or driving substrate.
  • the positive (+) side and the negative (-) side are symmetrical with respect to the common voltage Vcom.
  • impurity ions gradually move to one side after a long period of operation, causing the optimal common voltage Vcom to shift, resulting in flicker and burn-in.
  • phase noise increases and phase stability decreases.
  • a work function adjustment layer 14 is provided on the plurality of reflective electrodes 13, in which a first layer 141 made of, for example, a silicon oxide (SiO x ) film and a second layer 142 made of a high dielectric film, which have different oxygen densities, are laminated.
  • a first layer 141 made of, for example, a silicon oxide (SiO x ) film and a second layer 142 made of a high dielectric film, which have different oxygen densities
  • the liquid crystal display panel 1 of this embodiment reduces the occurrence of flicker and burn-in, making it possible to improve reliability.
  • the liquid crystal display panel 1 of this embodiment can also be used as a beam steering device.
  • the beam steering device is a spatial phase modulation element that applies a gradual signal to each adjacent pixel to continuously modulate the phase for each pixel, thereby controlling the propagation direction of the wavefront.
  • the liquid crystal display panel 1 When using the liquid crystal display panel 1 for beam steering, it is important that the absolute values of the signals on the plus (+) side and minus (-) side for each frame at a given pixel are the same. In reality, the difference in work function between the electrodes causes the phase amount to deviate from the ideal value, resulting in phase amount noise. This can lead to a broad wavefront propagation angle, a blurred focused spot diameter in the case of focused light, and flickering in the case of holographic image reproduction.
  • the difference in work function between the multiple reflecting electrodes 13 and the opposing electrode 22 is eliminated, so the absolute values of the signals on the positive (+) side and the negative (-) side for each frame become approximately equal. This reduces noise in the phase amount, enabling high-quality image reproduction through highly accurate wavefront control.
  • FIG. 11 is a schematic diagram showing an example of a cross-sectional configuration of a display device (liquid crystal display panel 2) according to the first modified example of the present disclosure.
  • a display device liquid crystal display panel 2
  • the work function adjustment layer 14 may be formed continuously across the plurality of reflective electrodes 13. Even with such a configuration, the same effects as those of the above embodiment can be obtained.
  • (2-2. Modification 2) 12 is a schematic diagram showing an example of a cross-sectional configuration of a display device (liquid crystal display panel 3) according to Modification 2 of the present disclosure.
  • the liquid crystal display panel 3 is used, for example, as a light valve (e.g., liquid crystal panels 322A, 322B, 322C) of a projection-type display device (projection-type display device 5) such as a projector described later.
  • a work function adjustment layer 14 was provided on a plurality of reflective electrodes 13.
  • a work function adjustment layer 25 which is made up of a plurality of layers having different oxygen densities, is formed on the surface of the counter electrode 22 facing the liquid crystal layer 30 (hereinafter simply referred to as on the counter electrode 22).
  • the work function adjustment layer 25 corresponds to a specific example of the "laminated film" of the present disclosure, and as described above, is provided on the counter electrode 22. Like the work function adjustment layer 14, the work function adjustment layer 25 is intended to adjust the work function difference between the multiple reflective electrodes 13 and the counter electrode 22, which is provided on the counter substrate 20 side and formed using a conductive material having optical transparency.
  • the work function adjustment layer 25 changes the apparent work function of the counter electrode 22 by forming an interface dipole on the counter electrode 22.
  • the work function adjustment layer 25 is a laminated film in which multiple layers (first layer 251 and second layer 252) with different oxygen densities are stacked. When films with different oxygen densities are stacked, oxygen moves from the layer with the higher oxygen density to the layer with the lower oxygen density. This causes a charge transfer due to the generation of oxygen vacancies, and the work function shifts.
  • the counter electrode 22 made of indium tin oxide (ITO) has a work function of about 4.1 eV.
  • the work function of the multiple reflective electrodes 13 made of aluminum with respect to the counter electrode 22 varies depending on the crystal orientation.
  • the crystal plane of Al(100) has a work function of 4.20 eV
  • the crystal plane of Al(110) has a work function of 4.06 eV
  • the crystal plane of Al(111) has a work function of 4.26 eV.
  • it is preferable that the first layer 251 and the second layer 252 have an oxygen density difference of 0.2 eV or more. This makes it possible to eliminate the work function difference between the multiple reflective electrodes 13 and the counter electrode 22.
  • the first layer 251 is made of, for example, a silicon oxide (SiO x ) film.
  • the thickness of the first layer 251 is, for example, not less than 0 nm and not more than 100 nm, and preferably, for example, not less than 0 nm and not more than 50 nm.
  • the second layer 252 is made of a high dielectric constant film having a higher dielectric constant than the first layer 251.
  • materials constituting the second layer 252 include aluminum oxide (AlO x ), tantalum oxide (TaO x ), titanium oxide (TiO x ), zirconium oxide (ZrO x ), hafnium oxide (HfO x ), scandium oxide (ScO x ), magnesium oxide (MgO x ), yttrium oxide (YO x ), lanthanum oxide (LaO x ), lutetium oxide (LuO x ), and strontium oxide (SrO x ).
  • the thickness of the second layer 252 is, for example, 0 nm or more and 100 nm or less, and preferably , for example, 0 nm or more and 50 nm or less.
  • the work function adjustment layer 25 is laminated on the counter electrode 22 in the order of the second layer 252 and the first layer 251.
  • the constituent material of the second layer 252 relative to the first layer 251 made of a SiO x film is appropriately selected depending on the work function difference between the plurality of reflective electrodes 13 and the counter electrode 22 .
  • the second layer 252 can be formed using YOx , LaOx , LuOx , or SrOx among the above-mentioned constituent materials.
  • the second layer 252 can be formed using AlO x , TaO x , TiO x , ZrO x , HfO x , ScO x or MgO x among the above-mentioned constituent materials.
  • a third layer 253 is preferably formed on the surface of the work function adjustment layer 25.
  • the third layer 253 is used as a stopper film in the CMP process for planarizing the surface of the opposing substrate 20.
  • the third layer 253 can be formed using, for example, silicon nitride (SiN x ).
  • a work function adjustment layer 25 is provided on the counter electrode 22, in which a first layer 251 made of, for example, a silicon oxide (SiO x ) film and a second layer 252 made of a high dielectric film, each having different oxygen densities, are laminated.
  • a first layer 251 made of, for example, a silicon oxide (SiO x ) film and a second layer 252 made of a high dielectric film, each having different oxygen densities
  • (2-3. Modification 3) 15 is a schematic diagram showing an example of a cross-sectional configuration of a display device (liquid crystal display panel 4) according to Modification 3 of the present disclosure.
  • the liquid crystal display panel 4 is used, for example, as a light valve (e.g., liquid crystal panels 322A, 322B, 322C) of a projection-type display device (projection-type display device 5) such as a projector described later.
  • liquid crystal display panels 1 to 3 an example was shown in which a work function adjustment layer 14 was provided on the multiple reflective electrodes 13 or on the counter electrode 22.
  • a work function adjustment layer 14, 25 consisting of multiple layers with different oxygen densities stacked on the multiple reflective electrodes 13 and the counter electrode 22 is formed, respectively.
  • a work function adjustment layer 14 is provided on the plurality of reflective electrodes 13, in which a first layer 141 made of, for example, a silicon oxide (SiO x ) film and a second layer 142 made of a high dielectric film, which have different oxygen densities, are laminated, and further, a work function adjustment layer 25 is provided on the counter electrode 22, in which a first layer 251 made of, for example, a silicon oxide (SiO x ) film and a second layer 252 made of a high dielectric film, which have different oxygen densities, are laminated.
  • a first layer 251 made of, for example, a silicon oxide (SiO x ) film and a second layer 252 made of a high dielectric film, which have different oxygen densities
  • Application Examples> 16 is a functional block diagram showing the overall configuration of a display device (projection display device 5) according to Application Example 1.
  • the projection display device 5 is a display device that projects an image onto, for example, a screen 700 (projection surface).
  • the projection display device 5 is connected to, for example, an external image supply device such as a computer such as a PC (not shown) or various image players via an I/F (interface), and projects an image onto the screen 700 based on an image signal input to the interface.
  • an external image supply device such as a computer such as a PC (not shown) or various image players via an I/F (interface)
  • the projection display device 5 includes, for example, a light source device 500, a control unit 510, a light source driving unit 520, a light modulation device 530, an image processing unit 540, a frame memory 550, a panel driving unit 560, a projection optical system driving unit 570, and a projection optical system 600.
  • the light source device 500 includes a light source driver that drives the light source, and a current value setting unit that sets the current value when driving the light source, although these are not shown.
  • the light source driver generates a current having a current value set by the current value setting unit, based on the power supplied from a power supply circuit, not shown, in synchronization with a signal input from the light source driving unit 520. The generated current is supplied to each of the light sources.
  • the control unit 510 controls the light source driving unit 520, the image processing unit 540, the panel driving unit 560, and the projection optical system driving unit 570.
  • the light source driving unit 520 outputs a signal for controlling the light emission timing of the light source arranged in the light source device 500.
  • This light source driving unit 520 includes, for example, a PWM setting unit, a PWM signal generating unit, and a limiter (not shown), and controls the light source driver of the light source device 500 based on the control of the control unit 510, and PWM controls the light source to turn the light source on and off or adjust the brightness.
  • the light modulation device 530 generates image light by modulating the light (illumination light) output from the light source device 500 based on an image signal.
  • the light modulation device 530 is configured to include, for example, three light valves (e.g., the above-mentioned liquid crystal display panel 1) corresponding to each of the RGB colors described below.
  • a liquid crystal display panel (liquid crystal panel (R)) that modulates red light (R)
  • the RGB color lights modulated by the light modulation device 530 are synthesized by a cross dichroic prism (not shown) or the like, and are guided to the projection optical system 600.
  • the image processing unit 540 acquires an image signal input from the outside and performs tasks such as determining the image size, resolution, and whether it is a still image or a moving image. If it is a moving image, it also determines image data attributes such as the frame rate. Furthermore, if the resolution of the acquired image signal differs from the display resolution of each liquid crystal panel of the light modulation device 530, it performs resolution conversion processing.
  • the image processing unit 540 loads the images after each of these processes into the frame memory 550 for each frame, and outputs the image for each frame loaded into the frame memory 550 to the panel driving unit 560 as a display signal.
  • the panel driver 560 drives each of the liquid crystal panels R, G, and B of the light modulation device 530. By driving this panel driver 560, the light transmittance of each pixel arranged on each of the liquid crystal panels R, G, and B changes, and an image is formed.
  • the projection optical system drive unit 570 includes a motor that drives the lenses arranged in the projection optical system 600.
  • This projection optical system drive unit 570 drives, for example, the projection optical system 600 according to the control of the control unit 510, and performs, for example, zoom adjustment, focus adjustment, and aperture adjustment.
  • the projection optical system 600 includes a group of lenses and the like for projecting the light modulated by the liquid crystal display panel 1 (each of the liquid crystal panels R, G, and B of the light modulation device 530) onto the screen 700 to form an image.
  • Example of the configuration of a projection display device 17 is a schematic diagram showing another example (projection display device 5A) of the overall configuration of the optical system that constitutes the projection display device 5.
  • the projection display device 5A is a reflective 3LCD type projection display device that performs light modulation using a reflective liquid crystal display (LCD) panel.
  • the projection display device 5A includes, in order, a light source device 500, an illumination optical system 310, an image forming unit 320, and a projection optical system 600.
  • the illumination optical system 310 has, for example, from a position close to the light source device 500, a fly-eye lens 311 (311A, 311B), a polarization conversion element 312, a lens 313, dichroic mirrors 314A, 314B, reflecting mirrors 315A, 315B, lenses 316A, 313B, a dichroic mirror 317, and polarizing plates 318A, 318B, 318C.
  • the fly-eye lens 311 (311A, 311B) is intended to homogenize the illuminance distribution of the illumination light from the light source device 500.
  • the polarization conversion element 312 functions to align the polarization axis of the incident light in a specific direction, for example, by converting randomly polarized light into P-polarized light.
  • Lens 313 focuses the light from the polarization conversion element 312 onto dichroic mirrors 314A and 314B.
  • Dichroic mirrors 314A and 314B selectively reflect light in a specific wavelength range and selectively transmit light in other wavelength ranges.
  • dichroic mirror 314A mainly reflects red light Lr and green light Lg toward reflecting mirror 315A.
  • Dichroic mirror 314B mainly reflects blue light Lb toward reflecting mirror 315B.
  • Reflecting mirror 315A reflects the light (mainly red light Lr and green light Lg) from dichroic mirror 314A toward lens 316A.
  • Reflecting mirror 315B reflects the light (mainly blue light Lb) from dichroic mirror 314B toward lens 316B.
  • Lens 316A transmits the light (mainly red light Lr and green light Lg) from reflecting mirror 315A and focuses it on dichroic mirror 317.
  • Lens 316B transmits the light (mainly blue light Lb) from reflecting mirror 315B and focuses it on polarizing plate 318B.
  • Dichroic mirror 317 selectively reflects green light Lg toward polarizing plate 318C and selectively transmits light in other wavelength ranges.
  • the polarizing plates 318A, 318B, and 318C each include a polarizer with a polarization axis in a specific direction. For example, when the light is converted to P-polarized light by the polarization conversion element 312, the polarizing plates 318A, 318B, and 318C transmit the P-polarized light and reflect the S-polarized light.
  • the image forming unit 320 has reflective polarizing plates 321A, 321B, and 321C, liquid crystal panels 322A, 322B, and 322C, and a dichroic prism 323.
  • Reflective polarizing plates 321A, 321B, and 321C transmit light with the same polarization axis as the polarization axis of the polarized light from polarizing plates 318A, 318B, and 318C (e.g., P-polarized light) and reflect light with a different polarization axis (S-polarized light).
  • reflective polarizing plate 321A transmits P-polarized red light Lr from polarizing plate 318A toward liquid crystal panel 322A.
  • Reflective polarizing plate 321B transmits P-polarized blue light Lb from polarizing plate 318B toward liquid crystal panel 322B.
  • Reflective polarizing plate 321C transmits P-polarized green light Lg from polarizing plate 318C toward liquid crystal panel 322C.
  • Reflective polarizing plate 321A also reflects S-polarized red light Lr from liquid crystal panel 322A and makes it enter dichroic prism 323.
  • Reflective polarizing plate 321B reflects S-polarized blue light Lb from liquid crystal panel 322B and causes it to enter dichroic prism 323.
  • Reflective polarizing plate 321C reflects S-polarized green light Lg from liquid crystal panel 322C and causes it to enter dichroic prism 323.
  • Liquid crystal panels 322A, 322B, 322C perform spatial modulation of red light Lr, blue light Lb, and green light Lg, respectively, and correspond to the light modulation device 530 described above.
  • Liquid crystal panels 322A, 322B, 322C are electrically connected to a signal source (e.g., a PC, etc.) (not shown) that supplies an image signal containing image information.
  • a signal source e.g., a PC, etc.
  • Liquid crystal panels 322A, 322B, 322C modulate the incident light for each pixel based on the supplied image signal for each color, and generate a red image, a green image, and a blue image, respectively.
  • the dichroic prism 323 combines the incident red light Lr, blue light Lb, and green light Lg, and emits the combined light toward the projection optical system 600.
  • the projection optical system 600 has, for example, multiple lenses.
  • the projection optical system 600 magnifies the light emitted from the image forming unit 320 and projects it onto a screen 700, etc.
  • the present disclosure has been described above by giving the embodiment, modified examples 1 to 3, and application examples, but the present disclosure is not limited to the above-mentioned embodiment, etc., and various modifications are possible.
  • the reflective electrode 13 and the projection display device 5 of the present disclosure are not limited to the configurations described in the above-mentioned embodiment, etc.
  • a so-called three-panel projection display device 5 having three liquid crystal panels liquid crystal panels 322A, 322B, 322C
  • the present invention is not limited to this and can also be applied to a so-called two-panel projection display device having two liquid crystal panels or a single-panel projection display device.
  • the display device of the present disclosure can be applied to various display devices that modulate light from a light source via the liquid crystal display panel 1 (light modulation device 530) and display an image using a projection lens.
  • the display device of the present disclosure can be applied to head-up displays, Augmented Reality (AR) glasses, etc., in addition to the above-mentioned projector (projection-type display device 5).
  • the present technology can also be configured as follows. According to the present technology configured as follows, it is possible to improve reliability by eliminating the work function difference between the plurality of reflective electrodes and the common electrode.
  • the first layer is made of a silicon oxide film.
  • the laminated film is formed by laminating the first layer and the second layer in this order on the opposing surfaces of the plurality of reflective electrodes.
  • the plurality of reflective electrodes have a work function larger than that of the common electrode,
  • the second layer contains any one of yttrium oxide, lanthanum oxide, lutetium oxide, and strontium oxide.
  • the display device When the common electrode has a work function larger than that of the plurality of reflective electrodes, The display device according to (4) or (5), wherein the second layer contains any one of aluminum oxide, tantalum oxide, titanium oxide, zirconium oxide, hafnium oxide, scandium oxide, and magnesium oxide. (7) The display device described in any one of (3) to (6), wherein the stacked film is stacked in the order of the second layer and the first layer on the opposing surfaces of the multiple reflective electrodes. (8) When the plurality of reflective electrodes have a work function larger than that of the common electrode, The display device according to (7), wherein the second layer contains any one of aluminum oxide, tantalum oxide, titanium oxide, zirconium oxide, hafnium oxide, scandium oxide, and magnesium oxide.
  • the common electrode has a work function larger than that of the plurality of reflective electrodes
  • the second layer contains any one of aluminum oxide, tantalum oxide, titanium oxide, zirconium oxide, hafnium oxide, scandium oxide, and magnesium oxide.
  • the plurality of reflective electrodes are made of a metal film having light reflectivity.
  • the plurality of reflective electrodes are made of an aluminum film.
  • the common electrode is made of a conductive film having optical transparency.
  • a display device includes: a first substrate having a plurality of reflective electrodes provided for a plurality of pixels arranged in an array; a second substrate disposed opposite the first substrate and having a common electrode provided across the plurality of pixels; a liquid crystal layer provided between the first substrate and the second substrate; a laminated film provided on a surface of at least one of the plurality of reflective electrodes and the common electrode facing the liquid crystal layer, the laminated film having a first layer and a second layer having oxygen densities different from each other.

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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)

Abstract

Un dispositif à semi-conducteur (1) selon un mode de réalisation de la présente divulgation comprend un dispositif d'affichage comprenant : un premier substrat (10) qui a une pluralité d'électrodes réfléchissantes (13) qui sont disposées sur chacun d'une pluralité de pixels agencés dans un réseau ; un second substrat (20) qui est disposé face au premier substrat et qui a une électrode commune (22) qui est disposée à travers une pluralité de pixels ; une couche de cristaux liquides (30) qui est disposée entre le premier substrat et le second substrat ; et un film stratifié (14) qui est disposé sur une surface faisant face à une couche de cristaux liquides d'au moins l'une de l'électrode commune et de la pluralité d'électrodes réfléchissantes, et qui a une première couche (141) et une seconde couche (142) qui ont des densités d'oxygène mutuellement différentes.
PCT/JP2023/039809 2022-11-15 2023-11-06 Dispositif d'affichage et équipement électronique WO2024106236A1 (fr)

Applications Claiming Priority (2)

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JP2022182590 2022-11-15
JP2022-182590 2022-11-15

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WO2024106236A1 true WO2024106236A1 (fr) 2024-05-23

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005181829A (ja) * 2003-12-22 2005-07-07 Seiko Epson Corp 液晶装置、投射型表示装置
JP2010079154A (ja) * 2008-09-29 2010-04-08 Seiko Epson Corp 電気光学装置および電子機器
JP2014092692A (ja) * 2012-11-05 2014-05-19 Seiko Epson Corp 液晶装置、及び電子機器

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005181829A (ja) * 2003-12-22 2005-07-07 Seiko Epson Corp 液晶装置、投射型表示装置
JP2010079154A (ja) * 2008-09-29 2010-04-08 Seiko Epson Corp 電気光学装置および電子機器
JP2014092692A (ja) * 2012-11-05 2014-05-19 Seiko Epson Corp 液晶装置、及び電子機器

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