JP2005182076A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display equipped with a solar cell, which is improved in power generation of the solar cell by a light source having constant light quantity. <P>SOLUTION: The liquid crystal display is equipped with: a liquid crystal cell 2; a light source 4 irradiating the back face side of the liquid crystal cell 2; a light guide plate 3 to guide the light to the liquid crystal cell; a transflective means which is disposed between the liquid crystal cell 2 and the light guide plate 3 and which has a light transmitting region 23 and a light reflecting/photoelectric converting region 21 comprising a solar cell to reflect the incident light from the outside to the direction to the liquid crystal cell and to effect the photoelectric conversion by the incident light from the outside; and a reflective polarizing means 6 which is disposed between the transflective means and the light guide plate and which transmits a polarized light component necessary for the display by the liquid crystal cell and reflects a polarized component different from the above component to the light guide plate side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device including a solar cell among liquid crystal display devices.

  Liquid crystal display devices consume less power than CRT display devices, plasma display devices, etc., and can be made thin, so they are actively used as display elements for PDA terminals, mobile phones, notebook computers, video cameras, etc. ing. On the other hand, solar cells typified by amorphous silicon solar cells and single crystal silicon solar cells are used for calculators and the like because they can generate power only by irradiating light.

  By the way, it has been studied to save power consumption of a display device by mounting a solar cell on a liquid crystal display device and driving the display device using electric power obtained by the solar cell. As an example of this, there is a proposal of installing a solar cell in a plane including a liquid crystal display surface. However, since the installation area of the solar cell is limited, there is a limit to the power that can be obtained.

  For this reason, attempts have been made to arrange solar cells on the back side of the liquid crystal display surface. For example, in paragraph [0016] of Patent Document 1, attention is paid to the fact that the output light of the backlight light source is not completely used for the illumination of the liquid crystal display element, and the portion not used for the illumination of the liquid crystal display element ( For example, it is disclosed that a liquid crystal driving voltage can be obtained without requiring special energy by providing a solar cell on the back side of the backlight source 12 in FIG.

However, it is difficult to obtain a large amount of power from the solar cell only by providing the solar cell in a portion that is not an optical path for illuminating the liquid crystal display element.
JP 7-36417 A

  An object of the present invention is to provide a liquid crystal display device including a solar cell, in which the amount of solar cell power generated by a light source having a constant light amount is improved.

A liquid crystal display device according to the present invention includes a liquid crystal cell,
A light source that irradiates light to the back side of the liquid crystal cell;
A light guide plate for guiding the light to the liquid crystal cell;
It is disposed between the liquid crystal cell and the light guide plate, and is formed of a light transmission region and a solar cell that reflects light incident from the outside to the liquid crystal cell side and performs a photoelectric conversion reaction with the light incident from the outside. A transflective means comprising a reflective / photoelectric conversion region;
Reflective polarization means disposed between the transflective means and the light guide plate, and transmits a polarization component necessary for display by the liquid crystal cell and reflects a polarization component different from the polarization component to the light guide plate side. It is characterized by comprising.

  According to the liquid crystal display device according to the present invention, it is possible to improve the power generation amount of the solar cell per constant light quantity of the light source without impairing the visibility of the liquid crystal display, and it is possible to save power.

A first liquid crystal display device according to the present invention includes a liquid crystal cell,
A light source that irradiates light to the back side of the liquid crystal cell;
A light guide plate for guiding the light to the liquid crystal cell;
Reflective polarization means, which is disposed between the liquid crystal cell and the light guide plate, transmits a polarization component necessary for display by the liquid crystal cell and reflects a polarization component different from the polarization component to the light guide plate side,
A solar cell disposed so as to transmit the light at a position facing a side surface or a back surface of the light guide plate.

  Examples of liquid crystals contained in the liquid crystal cell include TN (twisted nematic), GH (guest-host), ECB (electrically controlled birefringence), STN (super-twisted nematic), and SBE (super-twisted birefringence effect). ) And the like.

  As the light source, for example, a light source provided with an arc tube can be used. Examples of the arc tube include a fluorescent tube (for example, a cold cathode tube and a hot cathode tube), a light bulb, and the like.

The light guide plate can be formed of, for example, a resin having transparency. Examples of the resin having transparency include an acrylic resin. In the light guide plate, a reflection plate can be disposed on the back surface to increase the reflectance. As such a reflector, for example, an aluminum foil, a thin film containing TiO ₂ particles, or the like can be used.

  The first liquid crystal display device according to the present invention may further include a diffusion plate in order to improve light diffusibility.

  The reflective polarizing means desirably has a function (circular dichroism) of transmitting only one of the circularly polarized components and reflecting the other. Examples of the reflective polarizing means having such a function include those provided with a sheet containing cholesteric liquid crystal.

  As the solar cell, for example, a crystalline silicon solar cell, a polysilicon solar cell, a compound semiconductor solar cell such as CdS / CdTe, a dye-sensitized solar cell, or the like can be used.

  According to the first liquid crystal display device, it is possible to increase the amount of power generated by the solar cell with a light source having a constant light amount, so that power saving can be achieved.

  In a liquid crystal display device including a light guide plate and a backlight disposed on the side of the light guide plate, only about 50% of the output light from the backlight is incident on the light guide plate because the light incident portion of the light guide plate is small. The rest disappears as heat. In addition, since only a specific polarization component of light incident on the liquid crystal cell from the light guide plate can be used for display by the liquid crystal cell, the remaining polarization component must be lost as heat. Therefore, in the present situation, a considerable amount of light emitted from the light source is lost as heat.

  According to the first liquid crystal display device, the light incident on the light guide plate from the light source and reflected by the light guide plate to the liquid crystal cell side is reflected in the reflection polarization means, and the polarization component necessary for display by the liquid crystal cell is reflected by the reflection polarization means. At the same time, a polarized light component different from the polarized light component is reflected to the light guide plate side by the reflective polarization means. For this reason, reflected light can be utilized for the electric power generation of a solar cell. Among the reflected light, there is light that is reflected again toward the liquid crystal cell by the light guide plate. Such light is again selectively transmitted and selectively reflected by the reflective polarization means, so that the selectively transmitted light can be used for the display of the liquid crystal cell, and is also selectively reflected. Can be used for power generation of solar cells. Furthermore, among the selectively reflected light, there is light that is reflected again to the liquid crystal cell side by the light guide plate. Therefore, such light is selectively transmitted and selectively reflected by the reflective polarization means three times. It can be carried out.

  Therefore, by repeating selective transmission and selective reflection by the reflective polarization means, it is possible to use light components that are not used in the display by the liquid crystal cell for power generation of the solar cell with high efficiency. The amount of power generation can be increased. In addition, since the amount of heat lost can be reduced, the light utilization efficiency can be increased.

  An example of a first liquid crystal display device according to the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing a schematic configuration of an example of a first liquid crystal display device according to the present invention, and FIGS. 2 and 3 are flowcharts illustrating the operation of the liquid crystal display device of FIG.

  The liquid crystal display device includes two polarizing plates 1a and 1b, and a liquid crystal cell 2 disposed between the polarizing plates 1a and 1b. The liquid crystal cell 2 has, for example, a structure in which a TN liquid crystal layer is sandwiched between a pair of substrates (for example, a glass substrate). The light guide plate 3 is formed of, for example, an acrylic plate whose front surface 3a is horizontal and whose back surface 3b is inclined. Such a light guide plate 3 is arranged on the back side of the liquid crystal cell 2. The light source includes a fluorescent lamp 4 and a curved reflecting plate 5 surrounding the back surface of the fluorescent lamp 4. This light source is disposed so as to face the side surface of the light guide plate 3. The reflective polarization means 6 is disposed between the liquid crystal cell 2 and the light guide plate 3. The reflective polarization means 6 includes a cholesteric liquid crystal-containing film 7 located on the light guide plate 3 side and a λ / 4 wavelength plate 8 located on the liquid crystal cell 2 side. The cholesteric liquid crystal-containing film 7 can transmit only one of the circularly polarized components and reflect the other. The solar cell 9 is disposed so as to face the back surface 3b of the light guide plate 3 with a gap.

  The operation of the liquid crystal display device configured as shown in FIG. 1 will be described with reference to FIGS. A part of the light emitted from the fluorescent lamp 4 directly enters the light guide plate 3, and the other part is incident on the light guide plate 3 after being reflected by the reflecting plate 5. The light A incident on the light guide plate 3 is reflected to the liquid crystal cell 2 side. Of the reflected light, only one of the counterclockwise circularly polarized light component and the clockwise circularly polarized light component (circularly polarized light component B) is transmitted through the cholesteric liquid crystal-containing film 7, and the remaining circularly polarized light component C is on the light guide plate 3 side. Is reflected.

  The circularly polarized light component B transmitted through the cholesteric liquid crystal-containing film 7 is converted into linearly polarized light D by the λ / 4 wavelength plate 8. Of this linearly polarized light D, only the light E oscillating in a specific direction is transmitted through the polarizing plate 1b, and this transmitted light E is incident on the liquid crystal cell 2, and this incident light is transmitted through the polarizing plate 1a, or the incident light is polarized. Brightness changes depending on whether it is blocked by the plate 1a, and liquid crystal display is performed.

  On the other hand, the other circularly polarized light component C reflected to the light guide plate 3 side by the cholesteric liquid crystal-containing film 7 is depolarized. Part (a) of the reflected light F is absorbed by the solar cell 9 and converted into electric power. Further, another part (b) of the reflected light F is reflected by the light guide plate 3 to the liquid crystal cell 2 side. In the reflected light F, only one circularly polarized component B is transmitted through the cholesteric liquid crystal-containing film 7 and the other circularly polarized component C is reflected by the cholesteric liquid crystal-containing film 7. The light transmitted through the cholesteric liquid crystal-containing film 7 is converted into linearly polarized light D by the λ / 4 wavelength plate 8, and only the light E that vibrates in a specific direction out of the linearly polarized light D is transmitted through the polarizing plate 1b. The light E enters the liquid crystal cell 2 and a liquid crystal display is performed. On the other hand, the other circularly polarized light component C reflected by the cholesteric liquid crystal-containing film 7 is partially (a) used for power generation of the solar cell 9, and the other part (b) is liquid crystal by the light guide plate 3. The light is reflected to the cell 2 side, and is selectively transmitted and selectively reflected by the reflective polarization means 6.

Therefore, as shown in FIG. 3, the light emitted from the light source is selectively transmitted and selectively reflected by the reflective polarization means 6, and the transmitted light L ₁ is used for display by the liquid crystal cell 2, and the reflected light. Part of M ₁ is used for power generation of the solar cell 9, and at the same time, another part is reflected again by the light guide plate 3 and reaches the reflection polarization means 6. This light is selectively transmitted and selectively reflected by the reflective polarization means 6, the transmitted light L ₂ is used for display by the liquid crystal cell ₂ , and part of the reflected light M ₂ is used for power generation by the solar cell 9. Then, the other part is reflected again by the light guide plate 3 and reaches the reflection polarization means 6. The reached light is selectively transmitted and selectively reflected by the reflective polarization means 6, the transmitted light L ₃ is used for display by the liquid crystal cell 2, and part of the reflected light M ₃ is used for power generation by the solar cell 9. At the same time, another part is reflected again by the light guide plate 3 and reaches the reflection polarization means 6.

  By repeating such selective transmission and selective reflection by the reflective polarizing means 6, the reflected light M from the reflective polarizing means 6, that is, the circularly polarized light component that cannot be used for display by the liquid crystal cell 2, is used for power generation of the solar cell 9. Since it can utilize efficiently, the electric power generation amount per fixed light quantity irradiated from a light source can be improved. At the same time, since the circularly polarized component (transmitted light L of the reflective polarization means 6) necessary for display by the liquid crystal cell 2 can be extracted again from the reflected light M, the disappearance due to thermal conversion can be reduced. , Light utilization efficiency can be improved.

  The first liquid crystal display device can include a color filter for colorization and other members for improving visibility. An example of this is shown in FIG. In the first liquid crystal display device having the configuration shown in FIG. 1 described above, the color filter 10 can be disposed between the polarizing plate 1 a and the liquid crystal cell 2.

  In the liquid crystal display device having the configuration shown in FIGS. 1 to 4 described above, the solar cell 9 is disposed away from the light guide plate 3 at a position facing the back surface of the light guide plate 3, but as shown in FIG. The solar cell 9 may be disposed on the reflection surface 5 a of the plate 5. Moreover, it is also possible to use the solar cell 9 processed into a curved shape instead of the reflecting plate 5.

  In the liquid crystal display device having the configuration shown in FIGS. 1 to 4 described above, the example applied to the transmissive liquid crystal display device has been described. However, the liquid crystal display device can be similarly applied to a transflective liquid crystal display device.

  As a solar cell used for the first liquid crystal display device, it is desirable to use a dye-sensitized solar cell.

  The dye-sensitized solar cell includes a substrate having a light receiving surface, a transparent conductive film formed on the inner surface of the substrate, an n-type semiconductor formed on the transparent conductive film and having a dye adsorbed on the surface. A counter electrode having an electrode, a counter substrate facing the n-type semiconductor electrode, a conductive film formed on a surface of the counter substrate facing the n-type semiconductor electrode, the conductive film of the counter electrode, and the n-type And an electrolyte that relays charge transport between the semiconductor electrodes.

  Hereinafter, the electrolyte, the transparent conductive film, the n-type semiconductor electrode, the dye, the counter substrate, and the conductive film will be described.

1) Electrolyte The form of the electrolyte can be liquid, gel or solid.

  The electrolyte preferably includes a reversible redox pair.

The reversible redox _couple can be supplied from, for example, a mixture of iodine (I ₂ ) and iodide, iodide, bromide, hydroquinone, TCNQ complex, or the like. In particular, a redox pair consisting of I ⁻ and I ₃ ⁻ is preferable. This redox couple is supplied, for example, from a mixture of iodine and iodide. Examples of the iodide include an alkali metal iodide, an organic compound iodide, and a molten salt of iodide.

  The electrolyte can further contain an organic solvent.

2) Transparent conductive film The transparent conductive film preferably has little absorption in the visible light region and has conductivity. Such a transparent conductive film is preferably a tin oxide film doped with fluorine or indium, or a zinc oxide film doped with fluorine or indium. Further, from the viewpoint of improving conductivity and preventing an increase in resistance, it is desirable to wire a low-resistance metal matrix in combination with the transparent conductive film.

3) n-type semiconductor electrode The n-type semiconductor electrode is preferably composed of a transparent semiconductor with little absorption in the visible light region. As such a semiconductor, a metal oxide semiconductor is preferable. Specifically, oxides of transition metals such as titanium, zirconium, hafnium, strontium, zinc, indium, yttrium, lanthanum, vanadium, niobium, tantalum, chromium, molybdenum or tungsten, SrTiO ₃ , CaTiO ₃ , BaTiO ₃ , MgTiO _{3 3} , perovskites such as SrNb ₂ O ₆ , or complex oxides or oxide mixtures thereof, GaN, and the like. Of these, TiO ₂ is preferable.

  Examples of the dye adsorbed on the surface of the n-type semiconductor electrode include a ruthenium-tris transition metal complex, a ruthenium-bis transition metal complex, an osmium-tris transition metal complex, and an osmium-bis transition. A metal complex, a ruthenium-cis-diaqua-bipyridyl complex, a phthalocyanine, a porphyrin, etc. can be mentioned.

4) Counter substrate The counter substrate preferably has little absorption in the visible light region and has conductivity. Such a substrate is preferably a tin oxide film, a zinc oxide film or the like.

5) Conductive film This conductive film can be formed from metals, such as platinum, gold | metal | money, and silver, for example.

  An example of a dye-sensitized solar cell is shown in FIG. FIG. 6 is a cross-sectional view obtained when an example of a dye-sensitized solar cell is cut along the electrode stacking direction.

  That is, the transparent conductive film 12 is formed on the glass substrate 11. A transparent n-type semiconductor electrode 13 is formed on the transparent conductive film 12. The semiconductor electrode 13 includes an aggregate of fine particles 14. Further, a single molecule is adsorbed on the surface of the semiconductor electrode 13. The surface of the transparent semiconductor electrode 13 can be a fractal shape having self-similarity like a resinous structure. The counter electrode 15 includes a glass substrate 16 and a conductive film 17 formed on the surface of the glass substrate 16 facing the semiconductor electrode 13. An electrolyte (for example, gel electrolyte) 18 is held in the pores in the semiconductor electrode 13 and is interposed between the semiconductor electrode 13 and the conductive film 17. The sealing member 19 containing an insulating resin (for example, an epoxy resin) is disposed between the glass substrate 11 and the glass substrate 16, and forms a sealed space between the glass substrate 11 and the glass substrate 16.

  In such a photosensitized solar cell, the light 20 incident from the glass substrate 11 side is absorbed by the dye adsorbed on the surface of the n-type semiconductor electrode 13, and then the dye is transferred to the n-type semiconductor electrode 13. And the dye passes holes to the electrolyte 18 to perform photoelectric conversion.

  Next, an example of a second liquid crystal display device according to the present invention will be described.

This liquid crystal display device
A liquid crystal cell;
A light source that irradiates light to the back side of the liquid crystal cell;
A light guide plate for guiding the light to the liquid crystal cell;
A transflective reflection layer, which is disposed between the liquid crystal cell and the light guide plate, includes a reflection / photoelectric conversion region and a light transmission region in which light incident from the outside is reflected to the liquid crystal cell side and a photoelectric conversion reaction by a solar cell occurs. Means.

  As the liquid crystal cell, the light guide plate, and the light source, those similar to those described in the first liquid crystal display device described above can be used.

  As the transflective means, for example, a solar cell is formed in an island shape on the surface of the thin film obtained by depositing metal particles, or the light guide plate side of the metal plate in which the through hole is formed. What formed the solar cell in the shape of an island on the surface can be used. As the solar cell, the same one as described in the first liquid crystal display device described above can be used.

Of the transflective means, a dye-sensitized solar cell integrated with a polarizing plate is preferably used. Such a polarizing plate integrated dye-sensitized solar cell includes a transparent conductive film formed on a polarizing plate, a semiconductor electrode formed on the transparent conductive film, and a counter electrode disposed so as to face the semiconductor electrode. With. The semiconductor electrode includes n-type semiconductor particles containing TiO ₂ particles and a dye adsorbed on the surface of the n-type semiconductor particles.

  According to such transflective means, light incident from the outside can be reflected by the n-type semiconductor electrode of the solar cell. Moreover, since a solar cell becomes a reflection area | region, the clearance gap which exists between solar cells can function as a light transmissive area | region.

  The second liquid crystal display device can irradiate the liquid crystal cell with light from the light source through the light transmission region of the transflective means, and can also transmit external light such as natural light and room illumination light to the transflective means. Since the light can be reflected toward the liquid crystal cell in the reflection / photoelectric conversion region, the transmissive display function and the reflective display function can be realized at the same time. Since the reflection / photoelectric conversion region is closer to the liquid crystal cell side, the light that was not used for the liquid crystal display can be used efficiently for power generation of the solar cell, and the power generation amount with a light source with a constant light amount can be improved. it can. In addition, since the amount of light that is converted into heat and disappears can be reduced, the light utilization efficiency can be increased.

By using the above-described polarizing plate-integrated dye-sensitized solar cell as a transflective means, n-type semiconductor particles containing TiO ₂ particles have light reflectivity. It can reflect light. Moreover, since a solar cell functions as a reflective area | region, the clearance gap which exists between solar cells can function as an area | region which light permeate | transmits. In addition, since the dye-sensitized solar cell is directly formed on the polarizing plate, the distance from the liquid crystal cell is reduced, and light that has not been used for liquid crystal display can be used efficiently for power generation. Can do a lot.

The dye-sensitized solar cell is transparent because it uses a semiconductor electrode containing TiO ₂ , and even if it is placed near the liquid crystal cell, the liquid crystal screen is not colored with the color of the solar cell, and visibility is improved. Can keep.

  In the second liquid crystal display device, it is preferable to dispose reflective polarizing means between the transflective means and the light guide plate. Since the solar cell is arranged in the vicinity of the liquid crystal cell, the amount of power generated by the solar cell can be increased by increasing the amount of light incident on the liquid crystal cell by repeating selective transmission and selective reflection by the reflective polarization means. .

  The second liquid crystal display device can include a color filter for colorization and other members for improving visibility.

  An example of the second liquid crystal display device is shown in FIGS. FIG. 7 is a cross-sectional view showing an example of a second liquid crystal display device according to the present invention, and FIG. 8 is an enlarged cross-sectional view showing a main part of the liquid crystal display device of FIG. 7 to 8, the same members as those described in FIGS. 1 to 6 are denoted by the same reference numerals and description thereof is omitted.

The liquid crystal display device having the configuration shown in FIG. 7 includes two polarizing plates 1a and 1b, a liquid crystal cell 2, a light guide plate 3, a light source having a fluorescent lamp 4 and a reflection plate 5. The dye-sensitized solar cell 21 is formed in an island shape on the surface of the polarizing plate 1b on the light guide plate 3 side. As shown in FIG. 8, the dye-sensitized solar cell 21 includes a transparent conductive film 12 formed on the surface of the polarizing plate 1b on the light guide plate 3 side, and a transparent n formed on the transparent conductive film 12. Type semiconductor electrode 13. The semiconductor electrode 13 is a layered material including metal oxide semiconductor particles 22 containing TiO ₂ particles and a dye adsorbed on the surface of the semiconductor particles 22. The counter electrode 15 includes a glass substrate 16 and a conductive film 17 formed on the surface of the glass substrate 16 facing the semiconductor electrode 13. An electrolyte (for example, gel electrolyte) 18 is held in the pores in the semiconductor electrode 13 and exists between the semiconductor electrode 13 and the conductive film 17. The sealing member 19 containing an insulating resin (for example, epoxy resin) is disposed between the polarizing plate 1 b and the glass substrate 16, and forms a sealed space between the polarizing plate 1 b and the glass substrate 16.

  According to the liquid crystal display device having such a configuration, the light a incident on the light guide plate 3 from the fluorescent lamp 4 and reflected toward the liquid crystal cell 2 passes through the gaps existing between the island-shaped solar cells 21. The light enters the polarizing plate 1b. That is, the gap 23 existing between the solar cells 21 functions as a transmission region. On the other hand, external light b such as natural light or room light is reflected to the liquid crystal cell 2 side by the n-type semiconductor electrode 13 of each solar cell 21 and enters the polarizing plate 1b. That is, the n-type semiconductor electrode 13 functions as a reflection region.

  Therefore, since the solar cell 21 can serve as a transflective means including a light transmission region and a reflection region for reflecting external light to the liquid crystal cell side, the structure of the liquid crystal display device can be simplified.

  Moreover, since the solar cell 21 is integrated with the polarizing plate 1b, the distance between the solar cell 21 and the liquid crystal cell 2 is reduced, and light that is not used in the liquid crystal cell 2 is efficiently used for power generation of the solar cell 21. be able to. As a result, it is possible to improve the power generation amount of the solar cell 21 with a constant light amount, and to reduce the loss due to the heat conversion of light and to increase the light use efficiency.

Furthermore, since the n-type semiconductor electrode containing TiO ₂ particles has high transparency, the transparency of the entire solar cell 21 can be increased, and the liquid crystal display screen is not colored with the color of the solar cell, and the visibility of the liquid crystal display screen is improved. Can be maintained.

  Another example of the second liquid crystal display device is shown in FIG. FIG. 9 is a sectional view showing another example of the second liquid crystal display device according to the present invention. In FIG. 9, members similar to those described in FIGS. 1 to 8 described above are denoted by the same reference numerals and description thereof is omitted.

  This liquid crystal display device is further provided with the reflection polarization means 6 in the liquid crystal display device having the structure shown in FIG.

  The reflective polarization means 6 is disposed between the dye-sensitized solar cell 21 that also serves as a transflective means and the light guide plate 3. The reflective polarization means 6 includes a cholesteric liquid crystal-containing film 7 located on the light guide plate 3 side and a λ / 4 wavelength plate 8 located on the liquid crystal cell 2 side.

  According to the liquid crystal display device having the configuration shown in FIG. 9, a part of the light emitted from the fluorescent lamp 4 is directly incident on the light guide plate 3, and the other part is reflected by the reflecting plate 5. Incident on the light guide plate 3. The light A incident on the light guide plate 3 is reflected to the liquid crystal cell 2 side. Of the reflected light, only one of the counterclockwise circularly polarized light component and the clockwise circularly polarized light component (circularly polarized light component B) is transmitted through the cholesteric liquid crystal-containing film 7, and the remaining circularly polarized light component C is on the light guide plate 3 side. Is reflected.

  The circularly polarized light component B transmitted through the cholesteric liquid crystal-containing film 7 is converted into linearly polarized light D by the λ / 4 wavelength plate 8. The linearly polarized light D passes through the gap 23 (light transmission region) existing between the dye-sensitized solar cells 21, and only the light E that vibrates in a specific direction is transmitted through the polarizing plate 1b. 2, the brightness changes depending on whether the incident light passes through the polarizing plate 1 a or is blocked by the polarizing plate 1 a, and a liquid crystal display is made.

  On the other hand, the other circularly polarized light component C reflected to the light guide plate 3 side by the cholesteric liquid crystal-containing film 7 is depolarized. A part of the reflected light is reflected by the light guide plate 3 to the liquid crystal cell 2 side. In this reflected light, only one circularly polarized component B is transmitted through the cholesteric liquid crystal-containing film 7 and the other circularly polarized component C is reflected by the cholesteric liquid crystal-containing film 7. The light transmitted through the cholesteric liquid crystal-containing film 7 is converted into linearly polarized light D by the λ / 4 wave plate 8, then passes through the light transmission region 23, and only the light E that vibrates in a specific direction out of the linearly polarized light D is used. Passes through the polarizing plate 1b, and the transmitted light E enters the liquid crystal cell 2 to display a liquid crystal. On the other hand, a part of the other circularly polarized light component C reflected by the cholesteric liquid crystal-containing film 7 is reflected to the liquid crystal cell 2 side by the light guide plate 3 and is selectively transmitted and selectively reflected by the reflective polarization means 6.

  By repeating the selective transmission and selective reflection by the reflective polarization means 6 as described above, the light reflected by the reflective polarization means 6, that is, the circularly polarized component C that cannot be used for display by the liquid crystal cell 2, is displayed by the liquid crystal cell 2. It becomes possible to extract again the circularly polarized light component B (transmitted light B of the reflective polarization means 6) necessary for the above. Therefore, since the light quantity of the circularly polarized light component B can be increased, the power generation amount of the solar cell 21 with respect to the light source having a constant light quantity can be improved. Moreover, since the loss | disappearance part by heat conversion can be decreased, the utilization efficiency of light can be improved.

  Next, an example of a third liquid crystal display device according to the present invention will be described.

The liquid crystal display device includes a liquid crystal cell,
A light source that irradiates light to the back side of the liquid crystal cell;
A light guide plate disposed on the back side of the liquid crystal cell and guiding the light to the liquid crystal cell;
A transparent conductive film formed on the back surface of the light guide plate, a semiconductor electrode formed on the transparent conductive film and including n-type semiconductor particles containing TiO ₂ particles, and disposed so as to face the semiconductor electrode. And a dye-sensitized solar cell provided with a counter electrode.

  Examples of the liquid crystal cell, the light source, and the light guide plate are the same as those described in the first liquid crystal display device. Moreover, the thing similar to what was mentioned above can be mentioned as a transparent conductive film, a semiconductor electrode, and a counter electrode which are contained in the said dye-sensitized solar cell.

  According to the third liquid crystal display device of the present invention, the light incident on the light guide plate from the light source can be reflected to the liquid crystal cell side by the semiconductor electrode of the dye-sensitized solar cell. It can be reduced and the light utilization efficiency can be increased. In addition, since the power generation element of the dye-sensitized solar cell is formed directly on the light guide plate, the dye-sensitized solar cell can be efficiently heated by the energy of light incident on the light guide plate, and the dye sensitization The energy conversion efficiency of the solar cell can be increased, and the amount of power generation can be increased.

  An example of the third liquid crystal display device is shown in FIG. FIG. 10 is a cross-sectional view showing an example of a third liquid crystal display device according to the present invention. In FIG. 10, members similar to those described in FIGS. 1 to 9 described above are denoted by the same reference numerals and description thereof is omitted.

The liquid crystal display device having the configuration shown in FIG. 10 includes two polarizing plates 1a and 1b, a liquid crystal cell 2, a light guide plate 3, a light source having a fluorescent lamp 4 and a reflection plate 5. The dye-sensitized solar cell 21 is integrated with the light guide plate 3. The dye-sensitized solar cell 21 includes a transparent conductive film 12 formed on the back surface of the light guide plate 3 and a transparent n-type semiconductor electrode 13 formed on the transparent conductive film 12. The semiconductor electrode 13 is a layered material including metal oxide semiconductor particles 22 containing TiO ₂ particles and a dye adsorbed on the surface of the semiconductor particles 22. The counter electrode 15 includes a glass substrate 16 and a conductive film 17 formed on the surface of the glass substrate 16 facing the semiconductor electrode 13. An electrolyte (for example, gel electrolyte) 18 is held in the pores in the semiconductor electrode 13 and exists between the semiconductor electrode 13 and the conductive film 17. The sealing member 19 containing an insulating resin (for example, epoxy resin) is disposed between the light guide plate 3 and the glass substrate 16, and forms a sealed space between the light guide plate 3 and the glass substrate 16.

  According to the liquid crystal display device having the configuration shown in FIG. 10, the light x incident on the light guide plate 3 directly from the fluorescent lamp 4 or after being reflected by the reflecting plate 5 is reflected to the liquid crystal cell side by the n-type semiconductor electrode 13. The Of the reflected light y, linearly polarized light having a specific vibration direction is transmitted through the polarizing plate 1b and incident on the liquid crystal cell 2 to perform liquid crystal display.

  Therefore, since the reflectance of the light guide plate 3 can be increased, loss due to scattering can be reduced. At the same time, since the power generation element of the dye-sensitized solar cell 21 is directly formed on the surface of the light guide plate 3, the power generation element can be efficiently heated by the energy of the incident light x incident on the light guide plate 3. The energy conversion efficiency of the sensitized solar cell 21 can be increased.

  In the liquid crystal display device having the configuration shown in FIG. 10, it is preferable to dispose the reflective polarizing means 6 between the polarizing plate 1 b and the light guide plate 3. By adopting such a configuration, light components other than the polarization component necessary for liquid crystal display can be efficiently used for power generation of the solar cell 21, and thus the power generation amount of the solar cell 21 per certain amount of light is further increased. be able to.

  In the liquid crystal display device having the configuration shown in FIG. 10 described above, the example applied to the transmissive liquid crystal display device has been described. However, the liquid crystal display device can be similarly applied to a transflective liquid crystal display device.

  Next, an example of a fourth liquid crystal display device according to the present invention will be described.

The liquid crystal display device includes a liquid crystal cell and an arc tube that irradiates light to the back side of the liquid crystal cell. The arc tube includes a transparent conductive film formed on a back surface, a semiconductor electrode formed on the transparent conductive film and containing semiconductor particles containing TiO ₂ particles, and a counter electrode facing the semiconductor electrode. Doubles as a dye-sensitized solar cell.

  Examples of the arc tube include a fluorescent tube (for example, a cold cathode tube, a hot cathode tube, etc.), a light bulb, and the like.

  Examples of the liquid crystal cell include the same ones as described in the first liquid crystal display device described above. In addition, examples of the transparent conductive film, the semiconductor electrode, and the counter electrode included in the dye-sensitized solar cell include the same ones as described in the first liquid crystal display device.

  According to the fourth liquid crystal display device of the present invention, since the dye-sensitized solar cell is used as the reflector of the arc tube, a sufficient amount of light for power generation can be secured. At the same time, since the power generation element of the dye-sensitized solar cell is formed directly on the surface of the arc tube, the power generation element can be efficiently heated by the heat energy emitted from the arc tube, and the dye-sensitized solar cell The energy conversion efficiency can be increased. As a result, the power generation amount of the dye-sensitized solar cell with a constant light source can be increased.

  An example of the fourth liquid crystal display device is shown in FIGS. FIG. 11 is a sectional view showing an example of a fourth liquid crystal display device according to the present invention, and FIG. 12 is an enlarged sectional view showing a main part of the liquid crystal display device of FIG. 11 to 12, members similar to those described in FIGS. 1 to 10 described above are denoted by the same reference numerals, and description thereof is omitted.

The liquid crystal display device having the configuration shown in FIG. 11 includes two polarizing plates 1 a and 1 b, a liquid crystal cell 2, a light guide plate 3, and a light source having a fluorescent lamp 4. The dye-sensitized solar cell 21 is integrated with the fluorescent lamp 4 and functions as a reflector. The dye-sensitized solar cell 21 includes a transparent conductive film 12 formed on the back surface of the fluorescent lamp 4 and a transparent n-type semiconductor electrode 13 formed on the transparent conductive film 12. The semiconductor electrode 13 is a layered material including metal oxide semiconductor particles containing TiO ₂ particles and a dye adsorbed on the surface of the semiconductor particles. The counter electrode 15 includes a glass substrate 16 and a conductive film 17 formed on the surface of the glass substrate 16 facing the semiconductor electrode 13. An electrolyte (for example, gel electrolyte) 18 is held in the pores in the semiconductor electrode 13 and exists between the semiconductor electrode 13 and the conductive film 17. The sealing member 19 containing an insulating resin (for example, epoxy resin) is disposed between the surface of the fluorescent tube 4 and the glass substrate 16, and forms a sealed space between the surface of the fluorescent tube 4 and the glass substrate 16. Yes.

  According to the liquid crystal display device having the configuration shown in FIG. 11, since the dye-sensitized solar cell 21 also serves as the reflector of the fluorescent lamp 4, a sufficient amount of light for power generation can be secured. Further, since the power generation element of the dye-sensitized solar cell 21 is directly formed on the surface of the fluorescent lamp 4, the heat energy emitted from the fluorescent lamp 4 is efficiently transmitted to the dye-sensitized solar cell 21 for heating. The energy conversion efficiency of the dye-sensitized solar cell 21 can be improved. Therefore, the power generation amount of the dye-sensitized solar cell 21 can be significantly increased.

  Further, in the liquid crystal display device having the configuration shown in FIG. 11, the example applied to the transmissive liquid crystal display device has been described. However, the liquid crystal display device can be similarly applied to a transflective liquid crystal display device.

  The 1st-4th liquid crystal display device which concerns on this invention can be equipped with the electrical circuit which can be charged with a solar cell. An example of such an electric circuit is shown in FIG. FIG. 13 is a block diagram showing an electric circuit that can be charged by a solar cell, included in the first to fourth liquid crystal display devices according to the present invention. That is, the solar cell 9 having a curved shape is disposed on the back side of the fluorescent lamp 4 and also functions as a reflector. This solar cell 9 is electrically connected to a secondary battery 32 having a backflow prevention diode 31. The electric power generated by the solar battery 9 is stored in the secondary battery 32. Examples of the secondary battery 31 include an alkaline secondary battery such as a nickel cadmium secondary battery and a nickel hydride secondary battery, and a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery.

  In addition, the first to fourth liquid crystal display devices according to the present invention can include an electric circuit for supplying power to a liquid crystal panel as a liquid crystal display unit. An example of such an electric circuit is shown in FIG. FIG. 14 is a block diagram showing an example of the flow of power supply in the first to fourth liquid crystal display devices according to the present invention.

  The current supplied from the solar cell 9 or the secondary battery 32 is operated using the LCD controller 35 including the voltage stabilizing circuit 33 and the booster circuit 34, and power is supplied to the liquid crystal panel 36.

[Example]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings described above.

  Note that the liquid crystal display devices of the examples and comparative examples described below each have a lithium-ion secondary battery 32 having the backflow prevention diode 31 shown in FIG. 13 and the power supply having the configuration shown in FIG. Circuit.

(Example 1)
Using the dye-sensitized solar cell manufactured by the method described below, a transmissive liquid crystal display device having the configuration shown in FIG. 1 was obtained.

After adding nitric acid to a TiO ₂ powder having an average primary particle size of 30 nm, a paste kneaded with pure water and further stabilized with a surfactant was prepared. After applying paste on a glass substrate on which ITO (Indium Tin Oxide) film, which is a transparent conductive film, is formed, heat treatment is performed at a temperature of 450 ° C. for 30 minutes to form a film-like material containing TiO ₂ powder. Got.

Next, a dry ethanol solution of cis-bis (ciocyanato) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) dihydrate) (temperature about 80 ° C.) Then, the ruthenium complex as a pigment was supported on the surface of the TiO ₂ powder by pulling it up in an argon stream to obtain an n-type semiconductor electrode.

  A fluorine-doped tin oxide electrode (conductive film) with platinum was formed on a glass substrate to obtain a counter electrode. With a spacer interposed between the counter electrode and the n-type semiconductor electrode, an epoxy resin is filled between the peripheral edge of the counter electrode and the peripheral edge of the n-type semiconductor electrode, leaving a space for the electrolyte inlet. The photoelectric conversion element unit was obtained.

  Next, 1-methyl-3-propylimidazolium iodide, tetrapropylammonium iodide, potassium iodide and iodine were dissolved to prepare an electrolyte. Poly (4-vinylpyridine) was dissolved in this electrolyte. Thereafter, 1,6-dibromohexane was dissolved in the solution to obtain an electrolyte composition as a gel electrolyte precursor.

  After injecting the electrolyte composition from the injection port of the photoelectric conversion element unit, sealing the injection port with an epoxy resin, and then heating it with a hot plate to gel the electrolyte composition, the structure shown in FIG. A dye-sensitized solar cell was produced.

(Example 2)
After applying the same paste as described in Example 1 on the KBr plate, heat treatment was performed at 450 ° C. for 30 minutes to obtain a film-like material containing TiO ₂ powder. This film-like material was mixed with cis-bis (thiocyanato) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) dihydrate) in a dry ethanol solution (temperature about And the ruthenium complex as a pigment was supported on the surface of the TiO ₂ powder. Subsequently, an ITO (Indium Tin Oxide) film was formed on the surface of the film by sputtering to obtain a laminated film.

  A laminated film was placed on the surface of the acrylic resin light guide plate so that the ITO film was in contact with the light guide plate, and these were adhered using an adhesive. These were immersed in water to remove KBr, and the n-type semiconductor electrode was transferred to the surface of the light guide plate.

  Epoxy resin leaving a space for the electrolyte inlet between the periphery of the counter electrode and the light guide plate with a spacer interposed between the counter electrode and the light guide plate similar to that described in Example 1 And a photoelectric conversion element unit was obtained.

  Next, after injecting an electrolyte composition similar to that described in Example 1 from the injection port of the photoelectric conversion element unit, the injection port is sealed with an epoxy resin and heated on a hot plate to gel the electrolyte composition. Thus, a dye-sensitized solar cell having the structure shown in FIG. 10 and integrated with the light guide plate was manufactured.

  This light guide plate-integrated dye-sensitized solar cell is used in place of the light guide plate 3 in the liquid crystal display device of Example 1, and the solar cell 9 disposed on the back side of the light guide plate 3 is removed, and the liquid crystal of Example 2 is removed. A display device was obtained.

(Example 3)
A transparent conductive film was provided on the surface of a glass tube used in a fluorescent lamp, and a paste similar to that described in Example 1 was applied to the upper portion by an ink jet method, followed by heat treatment at 450 ° C. for 30 minutes. Thereafter, the same polar glass was brought into close contact with the spacers dispersed, and the counter electrode was fixed by thermal fusion. After injecting an electrolyte composition similar to that described in Example 1 from the gap between the spacers, the injection port is sealed, and the electrolyte composition is gelled by heating to form a curved dye-sensitized solar cell. A battery was manufactured.

  Instead of the reflecting plate 5 of the fluorescent lamp 4 in the liquid crystal display device of Example 1, a solar cell 9 having a curved shape is used, and the solar cell 9 disposed on the back side of the light guide plate 3 is removed, and the solar cell 9 of Example 3 is removed. A liquid crystal display device was obtained.

(Comparative Example 1)
A liquid crystal display device having the structure shown in FIG. 15 was manufactured in the same manner as described in Example 1 except that the reflective polarizing means 6 was not used.

(Comparative Example 2)
A liquid crystal display device having the structure shown in FIG. 16 was manufactured in the same manner as described in Example 3 except that the reflective polarizing means 6 was not used.

About the liquid crystal display device of Examples 1-3 and Comparative Examples 1-2, after raising the electric power obtained from the solar cell to 4.5V with a DC-DC converter, it charged to the lithium ion secondary battery. Next, the liquid crystal display devices of Examples 1 to 3 and Comparative Examples 1 and 2 were operated using a lithium ion secondary battery as a driving power source, and the operation time was measured. It is shown in 1.

  As is clear from Table 1, the liquid crystal display devices of Examples 1 to 3 have a longer usage time when the lithium ion secondary battery is used as the driving power source than the liquid crystal display devices of Comparative Examples 1 and 2. Understand. From this result, it can be seen that according to the liquid crystal display devices of Examples 1 to 3, the power generation amount of the solar cell with a light source having a constant light amount can be improved.

Example 4
An ITO (Indium Tin Oxide) film was formed in an island shape on the surface of the glass polarizing plate. After applying the same paste as described in Example 1 above on each of the island-like ITO films, a heat treatment was performed at 450 ° C. for 30 minutes to obtain a film-like material containing TiO ₂ powder. . These are cis-bis (thiocyanato) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) dihydrate) in a dry ethanol solution (temperature about 80 ° C.). Then, the ruthenium complex as a pigment was supported on the surface of the TiO ₂ powder by pulling it up in an argon stream, and an n-type semiconductor electrode was formed on the polarizing plate.

  In the state where a spacer is interposed between the counter electrode and the n-type semiconductor electrode similar to those described in Example 1, a space for the electrolyte inlet is left between the periphery of the counter electrode and the polarizing plate. An epoxy resin was filled to obtain a photoelectric conversion element unit.

  Next, after injecting an electrolyte composition similar to that described in Example 1 from the injection port of the photoelectric conversion element unit, the injection port is sealed with an epoxy resin and heated on a hot plate to gel the electrolyte composition. Thus, a dye-sensitized solar cell integrated with the polarizing plate having the structure shown in FIG. 8 was manufactured.

  Using the obtained polarizing plate-integrated dye-sensitized solar cell, a transflective liquid crystal display device having the structure shown in FIG. 7 was manufactured.

(Example 5)
Except for disposing the reflective polarizing means 6 including the cholesteric liquid crystal-containing sheet 7 and the λ / 4 wavelength plate 8 between the solar cell 21 and the light guide plate 3, the same as described in the above-described Example 4 is used. A transflective liquid crystal display device having the structure shown in FIG. 9 was manufactured.

(Comparative Example 3)
In the liquid crystal display device of Comparative Example 1 having the structure shown in FIG. 15 described above, an aluminum transflective film was formed on the surface of the glass polarizing plate to obtain a transflective liquid crystal display device of Comparative Example 3.

For the transflective liquid crystal display devices of Examples 4 to 5 and Comparative Example 3, the operating time was measured when the lithium ion secondary battery was operated as a driving power source under the same conditions as described above, and the results were obtained. Table 2 below shows the operation time of Comparative Example 3 as 100.

  As can be seen from Table 2, the liquid crystal display devices of Examples 4 to 5 have a longer usage time than the liquid crystal display device of Comparative Example 3 when the lithium ion secondary battery is used as a drive power source. From this result, it can be seen that according to the liquid crystal display devices of Examples 4 to 5, it is possible to improve the power generation amount of the solar cell with the light source having a constant light amount.

(Example 6)
Using the same light guide plate-integrated dye-sensitized solar cell as described in Example 2 described above, a transmissive liquid crystal display device having the configuration shown in FIG. 10 was obtained.

(Comparative Example 4)
A transmissive liquid crystal display having the same configuration as that described in Example 6 except that a commercially available amorphous silicon solar cell is formed instead of forming a dye-sensitized solar cell on the back surface of the light guide plate. Got the device.

For the transmissive liquid crystal display devices of Example 6 and Comparative Example 4, the operating time was measured when the lithium ion secondary battery was operated as a driving power source under the same conditions as described above, and the results were compared with Comparative Example 4 Is shown in Table 3 below.

  As can be seen from Table 3, the liquid crystal display device of Example 6 has a longer usage time than the liquid crystal display device of Comparative Example 4 when the lithium ion secondary battery is used as the drive power source. From this result, according to the liquid crystal display device of Example 6, it can be seen that the power generation amount of the solar cell with the light source having a constant light amount can be improved.

(Example 7)
An ITO (Indium Tin Oxide) film was formed on the surface of the glass tube of the fluorescent lamp. After applying the same paste as described in Example 1 on the ITO film, a heat treatment was performed at 450 ° C. for 30 minutes to obtain a film-like material containing TiO ₂ powder. These are cis-bis (thiocyanato) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) dihydrate) in a dry ethanol solution (temperature about 80 ° C.). Then, the ruthenium complex as a pigment was supported on the surface of the TiO ₂ powder by pulling it up in an argon stream, and an n-type semiconductor electrode was formed on the glass tube.

  In the state where a spacer is interposed between the counter electrode and the n-type semiconductor electrode similar to those described in Example 1, a space for the electrolyte injection port is left between the peripheral edge of the counter electrode and the glass tube. An epoxy resin was filled to obtain a photoelectric conversion element unit.

  Next, after injecting an electrolyte composition similar to that described in Example 1 from the injection port of the photoelectric conversion element unit, the injection port is sealed with an epoxy resin and heated on a hot plate to gel the electrolyte composition. Thus, a dye-sensitized solar cell integrated with the fluorescent lamp having the structure shown in FIG. 12 was manufactured.

  Using the obtained fluorescent lamp-integrated dye-sensitized solar cell, a transmissive liquid crystal display device having the configuration shown in FIGS. 11 to 12 was obtained.

(Comparative Example 5)
Instead of forming a dye-sensitized solar cell on the back side of the fluorescent lamp, it has the same configuration as described in Example 7 except that a commercially available amorphous silicon solar cell is formed on the back side of the fluorescent lamp. A transmissive liquid crystal display device was obtained.

For the transmissive liquid crystal display devices of Example 7 and Comparative Example 5, the operating time when the lithium ion secondary battery was operated as a driving power source under the same conditions as described above was measured, and the result was compared with Comparative Example 5 Is shown in Table 4 below.

  As can be seen from Table 4, the liquid crystal display device of Example 7 has a longer usage time than the liquid crystal display device of Comparative Example 5 when the lithium ion secondary battery is used as the drive power source. From this result, it can be seen that according to the liquid crystal display device of Example 7, the power generation amount of the solar cell with a light source having a constant light amount can be improved.

1 is a cross-sectional view showing a schematic configuration of an example of a first liquid crystal display device according to the present invention. 2 is a flowchart illustrating the operation of the liquid crystal display device of FIG. 3 is another flowchart illustrating the operation of the liquid crystal display device of FIG. 1. Sectional drawing which shows schematic structure of another example of the 1st liquid crystal display device which concerns on this invention. Sectional drawing which shows an example of arrangement | positioning of the solar cell in the 1st liquid crystal display device which concerns on this invention. Sectional drawing obtained when an example of the dye-sensitized solar cell used for the liquid crystal display device which concerns on this invention is cut | disconnected along an electrode lamination direction. Sectional drawing which shows schematic structure of an example of the 2nd liquid crystal display device which concerns on this invention. The expanded sectional view which shows the principal part of the liquid crystal display device of FIG. Sectional drawing which shows schematic structure of another example of the 2nd liquid crystal display device which concerns on this invention. Sectional drawing which shows schematic structure of an example of the 3rd liquid crystal display device which concerns on this invention. Sectional drawing which shows schematic structure of an example of the 4th liquid crystal display device which concerns on this invention. FIG. 12 is an enlarged cross-sectional view illustrating a main part of the liquid crystal display device of FIG. 11. The block diagram which shows the electric circuit which can be charged with a solar cell contained in the 1st-4th liquid crystal display device which concerns on this invention. The block diagram which shows an example of the flow of the electric power supply in the 1st-4th liquid crystal display device which concerns on this invention. Sectional drawing which shows schematic structure of the liquid crystal display device of the comparative example 1. Sectional drawing which shows schematic structure of the liquid crystal display device of the comparative example 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a, 1b ... Polarizing plate, 2 ... Liquid crystal cell, 3a ... Light guide plate front surface, 3b ... Light guide plate back surface, 3 ... Light guide plate, 4 ... Fluorescent lamp, 5 ... Reflection plate, 6 ... Reflection polarization means, 7 ... Cholesteric liquid crystal containing Sheet, 8 ... 4 / λ wavelength plate, 9 ... solar cell.

Claims (5)

A liquid crystal cell;
A light source that irradiates light to the back side of the liquid crystal cell;
A light guide plate for guiding the light to the liquid crystal cell;
It is disposed between the liquid crystal cell and the light guide plate, and is formed of a light transmission region and a solar cell that reflects light incident from the outside to the liquid crystal cell side and performs a photoelectric conversion reaction with the light incident from the outside. A transflective means comprising a reflective / photoelectric conversion region;
Reflective polarization means disposed between the transflective means and the light guide plate, and transmits a polarization component necessary for display by the liquid crystal cell and reflects a polarization component different from the polarization component to the light guide plate side. A liquid crystal display device comprising:   The liquid crystal display device according to claim 1, wherein the solar cell is a dye-sensitized solar cell.   The transflective means comprises a polarizing plate and a reflection / photoelectric conversion region comprising a dye-sensitized solar cell formed with a gap serving as a light transmission region in the polarizing plate. Item 2. A liquid crystal display device according to item 1.   The liquid crystal display device according to claim 1, wherein the reflective polarization unit includes a cholesteric liquid crystal-containing sheet.   The said reflective polarizing means is provided with the cholesteric-liquid-crystal containing sheet | seat arrange | positioned at the said light-guide plate side, and the (lambda) / 4 wavelength plate arrange | positioned at the said semi-transmissive reflective means side. A liquid crystal display device according to item.

Images