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EP-4636468-B1 - CHOLESTERIC LIQUID CRYSTAL DISPLAY

EP4636468B1EP 4636468 B1EP4636468 B1EP 4636468B1EP-4636468-B1

Inventors

  • LIAO, CHI-CHANG
  • TOMITA, JUNJI

Dates

Publication Date
20260513
Application Date
20250409

Claims (15)

  1. A cholesteric liquid crystal display (1) comprising a first selective light reflection module (110) for reflecting a first light, a second selective light reflection module (120) for reflecting a second light, and a third selective light reflection module (130) for reflecting a third light, which sequentially stacked from bottom to top, the incident light going into said cholesteric liquid crystal display (1) from the top of said third selective light reflection module (130), wherein the wavelength ranges of said first light, said second light, and said third light are different; said cholesteric liquid crystal display (1) further comprises a first thin-film photovoltaic module (140) disposed between said third selective light reflection module (130) and said second selective light reflection module (120), and a second thin-film photovoltaic module (150) disposed between said second selective light reflection module (120) and said first selective light reflection module (110); wherein said first thin-film photovoltaic module (140) is partially photo-permeable in which the transmittance of said third light is lower than the transmittance of the other lights; wherein said second thin-film photovoltaic module (150) is partially photo-permeable in which the transmittance of said second light is lower than the transmittance of the other lights.
  2. The cholesteric liquid crystal display (1) of claim 1, wherein, said first selective light reflection module (110) is a red cholesteric liquid crystal module, said second selective light reflection module (120) is a green cholesteric liquid crystal module, said third selective light reflection module (130) is a blue cholesteric liquid crystal module; said first light is red light, said second light is green light, said third light is blue light; said first thin-film photovoltaic module (140) is a dye-sensitized solar cell module which comprising first dye sensitizers being specifically responsible for harvesting said third light; said second thin-film photovoltaic module (150) is a dye-sensitized solar cell module which comprising second dye sensitizers being specifically responsible for harvesting said second light.
  3. The cholesteric liquid crystal display (1) of claim 2, wherein, said first thin-film photovoltaic module (140) is a n-type dye-sensitized solar cell module which comprising a first semiconducting material selected from the group consisting of Titanium Dioxide (TiO 2 ), Niobium Pentoxide (Nb 2 O 5 ), Zinc Oxide (ZnO), Tin Oxide (SnO 2 ), and a combination of the above.
  4. The cholesteric liquid crystal display (1) of claim 2, wherein, said first thin-film photovoltaic module (140) is a p-type dye-sensitized solar cell module which comprising a first semiconducting material selected from the group consisting of Nickel Oxide (NiO), Cuprous Oxide (Cu 2 O), and a combination of the above.
  5. The cholesteric liquid crystal display (1) of claim 1, wherein, said second thin-film photovoltaic module (150) is a n-type dye-sensitized solar cell module which comprising a second semiconducting material selected from the group consisting of Titanium Dioxide (TiO 2 ), Niobium Pentoxide (Nb 2 O 5 ), Zinc Oxide (ZnO), Tin Oxide (SnO 2 ), and a combination of the above.
  6. The cholesteric liquid crystal display (1) of claim 1, wherein, said second thin-film photovoltaic module (150) is a p-type dye-sensitized solar cell module which comprising a second semiconducting material selected from the group consisting of Nickel Oxide (NiO), Cuprous Oxide (Cu 2 O), and a combination of the above.
  7. The cholesteric liquid crystal display (1) of claim 1, further comprising a light absorption module (160) disposed below said first selective light reflection module (110) for absorbing the light passed through said first selective light reflection module (110); said light absorption module (160) is a photovoltaic module.
  8. A cholesteric liquid crystal display (2) comprising a first cholesteric liquid crystal module (210) and a second cholesteric liquid crystal module (220), which sequentially stacked from top to bottom, the incident light going into said cholesteric liquid crystal display (2) from the top of said first cholesteric liquid crystal module (210), wherein said first cholesteric liquid crystal module (210) reflects a first light while said second cholesteric liquid crystal module (220) reflects a second light, wherein the wavelength range of said second light is different from that of said first light; said cholesteric liquid crystal display (2) further comprises a first thin-film photovoltaic module (240) disposed between said first cholesteric liquid crystal module (210) and said second cholesteric liquid crystal module (220); wherein said first thin-film photovoltaic module (240) is partially photo-permeable in which the transmittance of said first light is lower than the transmittance of the other lights; said first light is selected from the group consisting of blue light and green light, said second light is selected from the group consisting of green light and red light; said first thin-film photovoltaic module (240) is a dye-sensitized solar cell module which comprising first dye sensitizers being specifically responsible for harvesting said first light.
  9. The cholesteric liquid crystal display (2) of claim 8, wherein, said first thin-film photovoltaic module (240) is a n-type dye-sensitized solar cell module which comprising a first semiconducting material selected from the group consisting of Titanium Dioxide (TiO 2 ), Niobium Pentoxide (Nb 2 O 5 ), Zinc Oxide (ZnO), Tin Oxide (SnO 2 ), and a combination of the above.
  10. The cholesteric liquid crystal display (2) of claim 8, wherein, said first thin-film photovoltaic module (240) is a p-type dye-sensitized solar cell module which comprising a first semiconducting material selected from the group consisting of Nickel Oxide (NiO), Cuprous Oxide (Cu 2 O), and a combination of the above.
  11. The cholesteric liquid crystal display (2) of claim 8, further comprising a second thin-film photovoltaic module (250) disposed below said second cholesteric liquid crystal module (220), said second thin-film photovoltaic module (250) is a dye-sensitized solar cell module which comprising second dye sensitizers being specifically responsible for harvesting said second light, so that said second thin-film photovoltaic module (250) is partially photo-permeable in which the transmittance of said second light is lower than the transmittance of the other lights.
  12. The cholesteric liquid crystal display (2) of claim 11, wherein, said second thin-film photovoltaic module (250) is a n-type dye-sensitized solar cell module which comprising a second semiconducting material selected from the group consisting of Titanium Dioxide (TiO 2 ), Niobium Pentoxide (Nb 2 O 5 ), Zinc Oxide (ZnO), Tin Oxide (SnO 2 ), and a combination of the above.
  13. The cholesteric liquid crystal display (2) of claim 11, wherein, said second thin-film photovoltaic module (250) is a p-type dye-sensitized solar cell module which comprising a second semiconducting material selected from the group consisting of Nickel Oxide (NiO), Cuprous Oxide (Cu 2 O), and a combination of the above.
  14. The cholesteric liquid crystal display (2) of claim 11, further comprising a light absorption module (260) disposed below said second cholesteric liquid crystal module (220) for absorbing the light passed through said second cholesteric liquid crystal module (220).
  15. The cholesteric liquid crystal display (2) of claim 11, further comprising a light absorption module (260) disposed below said second thin-film photovoltaic module (250) for absorbing the light passed through said second thin-film photovoltaic module (250).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention pertains to the field of liquid crystal display technology, and in particular to the optical structure of a cholesteric liquid crystal display. 2. Description of Related Art A cholesteric liquid crystal display device has a plannar texture reflecting an external light or a focal conic texture transmitting an external light, depending on an electric field to be applied. Even if an electric field is not maintained in a specific texture, the cholesteric liquid crystal display device can maintain the corresponding texture. Thus, the cholesteric liquid crystal display device has bistability. Based on the bistability, the cholesteric liquid crystal display device has been utilized as an e-paper display. The cholesteric liquid crystal display device is capable of displaying colors depending on pitches of molecules contained in a liquid crystal layer and a wavelength of an incident light. US patent 6597419B1 shows a related prior art. A reflective type multilayer liquid crystal display has a blue, a green liquid, and a red liquid crystal light control layers stacked in this order from a viewing side. The half width of a reflection spectrum of any of the liquid crystal light control layers is larger than that of the adjoining liquid crystal light control layer on the viewing side. Further, the maximum reflectance of the reflection spectrum of any of the liquid crystal light control layers is higher than that of the adjoining liquid crystal light control layer on the viewing side. In one embodiment, the chromaticity coordinate position, in the XYZ colorimetric system, of a color displayed when all the liquid crystal light control layers are in a state of reflecting at the maximum reflectance is present in a range within a distance of 0.02 from the chromaticity coordinate position of the standard white point. Another prior art of reflective type multilayer liquid crystal display is shown in US patent application 20120274887A1. A cholesteric liquid crystal display device including a first liquid crystal panel containing a first cholesteric liquid crystal material for reflecting a light of a first color, a second liquid crystal panel containing a second cholesteric liquid crystal material for reflecting a light of a second color, a third liquid crystal panel containing a third cholesteric liquid crystal material for reflecting a light of a third color, a light absorption layer combined to a lower portion of the third liquid crystal panel, a first double-sided adhesive buffer layer configured to combine the second liquid crystal panel to a lower portion of the first liquid crystal panel and a second double-sided adhesive buffer layer configured to combine the third liquid crystal panel to a lower portion of the second liquid crystal panel. For improving the image quality, a prior art of US patent application 2013222749A1 is shown. A reflective liquid crystal display device includes an upper substrate, a lower substrate, a plurality of isolation structures, and a plurality of photoreactive liquid crystals. The lower substrate is disposed opposite to the upper substrate. The isolation structures are disposed between the upper substrate and the lower substrate for forming a plurality of channels between the upper substrate and the lower substrate. Each of the photoreactive liquid crystals is disposed in each of the channels. The upper substrate is used to block ultraviolet. US patent application 20210165255A1 shows another prior art for improving the image quality of a reflective cholesteric liquid crystal display. The display unit includes a upper transparent substrate, a lower substrate, a upper transparent electrode pattern formed on the upper transparent substrate, a lower transparent electrode pattern formed on the lower substrate, a cholesteric liquid crystal layer sandwiched between the upper transparent electrode pattern and the lower transparent electrode pattern, and a light absorbing layer formed on the upper transparent substrate. The cholesteric liquid crystal layer is used for generating a visible light including a wavelength range. The light absorbing layer is used for absorbing light outside the wavelength range, so that the visible light in the wavelength range passes through the light absorbing layer and the upper transparent substrate. Based on the above, the reflective cholesteric liquid crystal display is shown to reduce the emission of the light outside a specific wavelength range (e.g., first wavelength range) for improving image quality by using at least one light absorbing layer. US patent 6518944B1 shows another prior art. The structure of a layered color display in a bistable cholesteric liquid crystal layer has a transparent mode and a reflective mode, in which a black solar cell is placed in the bottom layer. It is characterized by the ability to efficiently generate electricity because solar cells can be placed the same