JP4559999B2 - Polarizer - Google Patents

Description

  The present invention relates to a polarizing plate in which polarizers that transmit only a specific polarization component are arranged on a glass plate.

  The polarizing plate is usually made of a crystal having directionality, and transmits only the polarization component of light that vibrates in one direction. Usually, this polarizing plate is applied to a liquid crystal display device such as a so-called projector.

  When producing a polarizing plate, a polarizer is produced by first drying a polyvinyl alcohol (PVA) film through a dyeing process, a crosslinking process, and a stretching process. On top of that, a polarizer protective film such as a triacetyl cellulose (TAC) film is bonded. Furthermore, a protective layer, an optical layer, an adhesive layer, and the like for the purpose of protecting the polarizing plate, imparting functions, or convenience for lamination are appropriately laminated on both surfaces.

  As a polarizing plate, a so-called wire grid type in which a wire grid is used as a polarizer has been proposed in addition to a technique for separating a polarized light component using a dye as described above.

  This wire grid type polarizing plate embeds micron-sized fine metal wires in a glass plate. As a result, when a polarization component parallel to the long axis direction of the metal thin wire is incident, electrons in the metal thin wire vibrate according to the light of the polarization component. Since the polarization direction of the light coincides with the vibration direction of the electrons in the fine metal wire, the light whose polarization direction is the same as the major axis direction of the fine metal wire is gradually attenuated by the vibration of the electrons. . As a result, the transmission of the polarization component parallel to the major axis direction of the fine metal wire is suppressed, and only the polarization component of the light orthogonal to the major axis direction is transmitted.

In recent years, for example, a wire grid polarizer as shown in Patent Document 1 has been proposed.
JP 2002-328234 A

  However, many of the above-mentioned conventional polarizing plates focus on the production cost and the polarization efficiency, and it is only necessary to be able to arrange them in the liquid crystal back panel. . However, many of the above-mentioned conventional polarizing plates focus on the production cost and the polarization efficiency, and it is only necessary to be able to arrange them in the liquid crystal back panel. . However, in recent years, with the progress of ultra-miniaturization of various devices including notebook computers and the like, it is necessary to make the polarizing plate ultra-miniaturized to a nanometer size. In particular, it is considered that future applications can be expanded by forming a polarizing plate that can be bent by configuring the thickness to a nanometer size.

  Further, when the size is reduced, the polarization efficiency is remarkably reduced, which is a big barrier to practical use.

  Therefore, the present invention has been devised in view of the above-described problems, and the object thereof is a polarizing plate that can be downsized to a nanometer size while maintaining the polarization efficiency at a mutual level. Is to provide.

  The invention according to claim 1 is a polarizing plate in which a polarizer that transmits only a specific polarization component is arranged in a glass plate, and the polarizer includes a plurality of quantum dots that absorb incident light. The quantum dot group is disposed in close proximity to the bottom of the quantum dot group and is substantially parallel to the incident-side metal rod having a length in the major axis direction of 1 μm or less and the incident-side metal rod. An emission-side metal rod having a length in a major axis direction shorter than the incidence-side metal rod is provided.

  According to a second aspect of the present invention, in the first aspect of the invention, the polarizer is configured such that the quantum dot group absorbs light of each polarization component through the quantum dots and is absorbed by the quantum dots. The energy based on the above is transitioned to the incident side metal rod, the energy emitted from the incident side metal rod is further guided to the emission side metal rod, and is emitted as propagating light. To do.

  Further, in the invention according to claim 3, in the invention according to claim 1 or 2, when the wavelength of incident light is λ, the incident-side metal rod has a length Li (<λ / 2), and the distance Ls between the incident-side metal rod and the emission-side metal rod is substantially equal to λ.

  In the present invention configured as described above, it is possible to reduce the size to the nanometer size while maintaining the polarization efficiency at a high level. For this reason, it becomes possible to cope with the progress of ultra-miniaturization of various devices such as notebook personal computers and the like, and since it can be a foldable polarizing plate, it can be used for various applications. .

  Hereinafter, as a best mode for carrying out the present invention, a polarizing plate in which a polarizer that transmits only a specific polarization component is arranged on a glass plate will be described in detail with reference to the drawings.

  A polarizing plate 1 to which the present invention is applied includes, for example, as shown in FIG. 1, a glass plate 11 and a polarizer 12 arranged in the glass plate 11.

  FIG. 2 shows an enlarged view of one polarizer 12. In the polarizer 12, a quantum dot group 21, a metal rod 23, and a metal rod 24 are arranged in this order from the incident side to the emission side.

  The quantum dot group 21 includes a plurality of quantum dots 22a to 22c that absorb incident light. In this quantum dot group 21, quantum dots 22 are formed in a row in the x direction in the figure. The quantum dot group 21 may be configured with any number of columns as long as it is arranged over one or more columns. The number of quantum dots 22 constituting one quantum dot group 21 is not limited to three, and any number of quantum dots 22 may be used as long as they are composed of a plurality. The quantum dots 22 constituting the quantum dot group 21 are not limited to being regularly arranged, and may be randomly arranged randomly.

  The quantum dots 22 control single electrons (excitons) based on discrete energy levels formed by confining excitons in three dimensions. In these quantum dots 22, the energy levels of carriers are made discrete by the exciton confinement system, and the state density can be sharpened in a delta function.

  The quantum dots 22 may be made of an AlGaAs material when absorbing red light, and may be made of an InGaN material when absorbing blue light.

  The incident side metal rod 23 is disposed close to the bottom of the quantum dot array 21. The incident-side metal rod 23 extends in a direction y that is perpendicular to the direction x in which the quantum dot array 21 extends. The incident-side metal rod 23 has a length Li in the major axis direction of 1 μm or less, and desirably Li <λ / 2 (λ is the wavelength of incident light). The incident-side metal rod 23 functions as a so-called antenna. If the length Li in the major axis direction exceeds λ / 2, the light loss increases and the polarization conversion efficiency is greatly reduced. It is because it ends up.

  The exit-side metal rod 24 is configured to be substantially parallel to the entrance-side metal rod 23, and the length in the major axis direction is shorter than that of the entrance-side metal rod 23. It is desirable that the distance Ls between the incident-side metal rod 23 and the emission-side metal rod 24 is substantially equal to λ. Similarly, the metal rod 24 on the emission side functions as a so-called antenna, and if it deviates from the above-described range, the loss of light increases and the polarization conversion efficiency is greatly reduced.

  When red light is incident on the polarizing plate 1, the metal rods 23 and 24 may be made of gold, copper, silver, or the like. Further, when blue light is incident on the polarizing plate 1, the metal wires 23 and 24 may be made of Al or silver.

  When light of each polarization direction x and y is incident on the polarizing plate 1 having such a configuration, the light is absorbed by the quantum dots 22 constituting the quantum dot group 21. And the energy based on the light of each polarization direction absorbed by this quantum dot 22 will change to the metal rod 23 on the incident side.

  In this connection, the incident-side metal rod 23 works so as to emit light in a direction of approximately 360 °, but the distance Ls between the incident-side metal rod 23 and the emission-side metal rod 24 is set as in the present invention. By making it substantially equal to λ, the metal rod 24 on the emission side functions as a so-called induction antenna. That is, the energy emitted from the incident-side metal rod 23 is guided to the emission-side metal rod 24 and emitted as propagating light. The polarization direction of the emitted propagating light depends on the orientation (y direction) of the metal rod 24 on the emitting side, and thus becomes the y direction.

  That is, in this polarizer 12, the polarization direction of the light incident by the polarization rotating unit 13 can be rotated in the y direction, and in the light emitting unit 14, these can be converted into propagating light and emitted. It becomes possible to function as the plate 1.

  In the polarizing plate 1 having the above-described configuration, the polarization direction of the absorbed light is changed in the y direction by providing the outgoing side metal rod 24 having a length equal to or shorter than the light wavelength in the vicinity of the incoming side metal rod 23. And can be converted. In particular, by providing a process of sucking light using the quantum dots 22, the polarization efficiency of light can be further improved.

It is a perspective view for demonstrating the structure of the polarizing plate to which this invention is applied. It is a schematic diagram of a structure of a polarizer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polarizing plate 11 Glass plate 12 Polarizer 21 Quantum dot row 22 Quantum dots 23 and 24 Metal rod

Claims (3)

In a polarizing plate in which polarizers that transmit only a specific polarization component are arranged in a glass plate,
The polarizer is
A quantum dot group in which a plurality of quantum dots that absorb incident light are arranged;
An incident-side metal rod that is disposed close to the bottom of the quantum dot group and has a major axis length of 1 μm or less;
A polarization bar comprising: an exit-side metal rod configured to be substantially parallel to the entrance-side metal rod and having a length in a major axis direction shorter than the entrance-side metal rod; Board. The polarizer is
The quantum dot group absorbs light of each polarization component through the quantum dots,
Transition energy based on the light absorbed by the quantum dots to the incident metal rod,
The polarizing plate according to claim 1, wherein the energy emitted from the incident-side metal rod is guided to the emission-side metal rod and emitted as propagating light. When the wavelength of incident light is λ,
The incident-side metal rod has a length Li (<λ / 2) in the major axis direction,
The polarizing plate according to claim 1, wherein a distance Ls between the incident-side metal bar and the emission-side metal bar is substantially equal to λ.

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