Patent Application
20130038818
The present disclosure relates to a display device that includes a light emitting layer containing quantum dots, a method of manufacturing the display device, and an electronic apparatus equipped with the display device.
Typically, liquid crystal display devices, organic-electro luminescence (EL) display devices, plasma display panel (PDP) devices, and the like are known as examples of display devices. In addition to these examples, currently, display devices that include a light emitting layer containing quantum dots are proposed (for example, see Japanese Unexamined Patent Application Publication No. 2010-156899).
In the above Japanese Unexamined Patent Application Publication No. 2010-156899, the display device containing quantum dots uses a laser light source, as a light source that emits excitation light. For display devices employing such a technique, the improvement of the utilization efficiency of the light is in demand. Accordingly, a proposal of a display device is desired, which facilitates the improvement of the utilization efficiency of light.
There is a need for a display device, a method of manufacturing the display device, and an electronic apparatus, capable of facilitating the improvement of the utilization efficiency of light.
A display device according to an embodiment of the present disclosure includes: a light source section emitting excitation light for each pixel; and a light emitting layer including a quantum dot and emitting emission light for each of the pixels, the quantum dot generating, based on the excitation light, the emission light having a wavelength longer than a wavelength of the excitation light.
A method of manufacturing a display device according to an embodiment of the present disclosure includes: forming a light source section that emits excitation light for each pixel; and forming, using a quantum dot, a light emitting layer that emits emission light for each of the pixels, the quantum dot being configured to generate, based on the excitation light, the emission light having a wavelength longer than a wavelength of the excitation light.
An electronic apparatus according to an embodiment of the present disclosure is provided with a display device. The display device includes: a light source section emitting excitation light for each pixel; and a light emitting layer including a quantum dot and emitting emission light for each of the pixels, the quantum dot generating, based on the excitation light, the emission light having a wavelength longer than a wavelength of the excitation light.
According to the display device, the method of manufacturing the display device, and the electronic apparatus of above respective embodiments of the present disclosure, the excitation light is emitted for each of the pixels by the light source section, and the emission light is emitted for each of the pixels by the light emitting layer that includes the quantum dot, based on the excitation light. The quantum dot generates, based on the excitation light, the emission light having a wavelength longer than a wavelength of the excitation light. This enables to make a wavelength conversion from the excitation light to the emission light with a simple configuration.
According to the display device, the method of manufacturing the display device, and the electronic apparatus of above respective embodiments of the present disclosure, the quantum dot included in the light emitting layer generate, based on the excitation light, the emission light having a wavelength longer than a wavelength of the excitation light. This makes it possible to make a wavelength conversion from the excitation light to the emission light with a simple configuration. Therefore, it is possible to facilitate the improvement of the utilization efficiency of light.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the technology as claimed.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the specification, serve to explain the principles of the technology.
Parts (A) to (C) of
Parts (A) to (C) of
Parts (A) to (C) of
Parts (A) and (B) of
Thereinafter, an embodiment of the present disclosure will be described in detail, with reference to the accompanying drawings. Note that a description will be given in the following order.
1. Embodiment (an example of using a semiconductor laser, a liquid crystal element, and multi-colored light emitting layers that contain quantum dots)
2. Application examples (examples of applying the display device to electronic apparatuses)
3. Modification examples
In an example illustrated in
The electrode 111n is an electrode to which electrons serving as carriers are to be injected, and is made of, for example, a metal material such as AuGe alloy or the like. Meanwhile, the electrode 111p is an electrode to which holes serving as carriers are to be injected, and is made of, for example, a metal material such as Ti/Pt/Au or the like.
The n-type substrate 110n is a substrate made of a semiconductor material such as n-type gallium arsenide (n-GaAs) or the like.
The p-type contact layer 115p is a contact layer made of a semiconductor material such as p-type gallium arsenide (p-GaAs) or the like. The insulating layer 114 functions as a current confining layer, and is made of an insulating material such as silicon oxide (SiO2) or the like.
The n-type cladding layer 112n is a layer that produces a confinement effect of light or carriers (electrons), and is made of a semiconductor material made of n-type aluminum gallium arsenide (n-AlGaAs) or the like. Meanwhile, the p-type cladding layer 112p is a layer that produces a confinement effect of light or carriers (holes), and is made of a semiconductor material made of p-type aluminum gallium arsenide (p-AlGaAs) or the like. In addition to these materials, InGaN-based semiconductor materials, CdZnMgSSe-based semiconductor materials, or other suitable semiconductor materials may be used.
The active layer 113 is a layer from which laser light L0 is to be emitted, and is made of a semiconductor material such as gallium arsenide (GaAs), InGaN, CdSe, or the like.
In the semiconductor laser configured above, the laser light (TE polarized laser light) L0 that is strongly polarized along the in-plane direction in the DH structure (in this case, the polarization direction is along an X axis) is emitted from the active layer 113. This laser light L0 has a far filed pattern (FFP) whose major and minor axes are along the Z and X axes, respectively.
The light guide plate 122 is an optical member that leads the laser light L0 incident from the laser light source 11 to the light modulation element 14 (and the light emitting layer 15).
The reflection plate 121 is an optical member that reflects the laser light L0 that would be emitted from the light guide plate 122 to the external through the back surface (a surface on the opposite side of the light modulation element 14), thereby returning the laser light L0 toward the light modulation element 14.
The diffuser plate 123 is an optical member that scatters the laser light L0 having been emitted from the light guide plate 122 toward the light modulation element 14, thereby suppressing the in-plane non-uniformity of the luminance of the laser light L0.
The light modulation element 14 is an element that has a function of modulating the laser light L0 incident from the diffuser plate 123 for each of pixels (red pixels 10R, green pixels 10R, and blue pixels 10R in this case), and is configured by a liquid crystal element, as an example, in this embodiment.
Each of the substrates 140A and 140B (a pair of substrates that oppose each other) is a substrate having a light transmitting property, and is configured by, for example, a glass substrate. Of these substrates, the substrate 140A has elements, such as thin-film transistors (TFTs) and the like, and wires (both not illustrated) formed therein.
Each of the incident side polarization plate 141A and the output side polarization plate 141B is an optical element that has a function of selectively allowing a specific polarization component contained in incident light to pass therethrough, but absorbing other polarization components therein. The incident side polarization plate 141A and the output side polarization plate 141B are arranged such that the respective light transmitting axes (polarization axes) thereof are orthogonal to each other (constituting the crossed Nichol arrangement), or are parallel to each other (constituting the parallel Nichol arrangement). In the example illustrated in
The pixel electrode 142A is individual electrodes formed for each of the pixels (or the red pixels 10R, the green pixels 10R, and the blue pixels 10R). Meanwhile, the common electrode 142B is an electrode formed entirely on the substrate 140B so as to be shared by the individual pixels.
The liquid crystal layer 143 is interposed (and sealed) between the substrates 140A and 140B (or between the pixel electrode 142A and the common electrode 142B), and may be configured by any of various liquid crystal materials.
In this embodiment, for example, each of the incident side polarization plate 141A, the light guide plate 122, and the like has a rectangular shape whose long and short sides extend along a Y axis and an X axis, respectively, as illustrated in
Specifically, in an example illustrated in
Meanwhile, in an example illustrated in
The driver section 16 controls an operation (light modulating operation) of the light modulation element 14 (or drives the light modulation element 14). Concretely, for example, when the light modulation element 14 is composed of the liquid crystal element configured above, the driver section 16 applies a voltage between the pixel electrode 142A and the common electrode 142B in accordance with an image signal for each pixel, thereby controlling the light modulating operation for each pixel. In this way, the light modulation element 14 composed of the liquid crystal element performs the light modulating operation for each of the pixels (or the red pixels 10R, the green pixels 10R, and the blue pixels 10R).
The light emitting layer 15 is configured by forming quantum dots in a resin material such as polystyrene or the like, and is a layer that emits emission light (display light) of a certain color for each of the pixels (or the red pixels 10R, the green pixels 10R, and the blue pixels 10R), on the basis of each laser light (each excitation light) L0 emitted from the light modulation element 14. In this embodiment, the light emitting layer 15 includes red light emitting layers 15R, green light emitting layers 15G, and blue light emitting layers 15B disposed in the red pixels 10R, the green pixels 10G, and the blue pixels 10B, respectively. In other words, the light emitting layer 15 includes multi-colored light emitting layers (or the red light emitting layers 15R, the green light emitting layers 15G, and the blue light emitting layers 15B) which are color-coded corresponding to the red pixels 10R, the green pixels 10G, and the blue pixels 10B. In addition, the quantum dots in the multi-colored light emitting layers are configured to generate emission light beams whose wavelengths (colors) differ from one another (or red, green, and blue emission light beams), on the basis of the corresponding excitation lights L0.
Examples of a material of these quantum dots include CdSe, CdS, ZnS:Mn, InN, InP, CuCl, CuBr, and Si, and the particle diameter (or the size of one side) of each quantum dot is, for example, approximately 2 nm to 20 nm. Among the materials of the quantum dots, InP or the like is given as an example of red light emitting material, CdSe or the like is given as an example of green light emitting material, and CdS or the like is given as an example of blue light emitting material.
The wavelength (corresponding to the photon energy) of each light emitted from the above light emitting layer 15 are varied by changing a size (particle diameters) R or a material composition of each quantum dot, for example, as depicted in Parts (A) to (C) of
In this embodiment, the quantum dots contained in the light emitting layer 15 (or the red light emitting layers 15R, the green light emitting layers 15G, and the blue light emitting layers 15B) are configured to generate emission light whose wavelength is longer than that of the excitation light L0, on the basis of the excitation light (laser light) L0. In other words, the quantum dots make a wavelength conversion from the excitation light L0 of a relatively short wavelength to the emission light of a relatively long wavelength. Consequently, a wavelength conversion is made from the excitation light L0 to the emission light with a simple configuration, as will be described in detail hereinafter.
The above display device 1 may be manufactured by, for example, the following processing. First, the light source section that emits the excitation light (laser light) L0 for each pixel is formed by using the laser light sources 11, the reflection plate 121, the light guide plate 122, the diffuser plate 123, and the light modulation element 14. Specifically, semiconductor lasers having the DH structure, for example, illustrated in
In this case, for example, when being composed of the liquid crystal element having the configuration illustrated in
Next, the light emitting layer 15 is formed on the top surface of the light modulation element 14 by using quantum dots. Specifically, the quantum dots are mixed into the above-mentioned resin material or the like while the above material and size (particle diameter) of the quantum dots are controlled. Then, the mixtures are applied to the light modulation element 14 independently of each of the pixels (or the red pixels 10R, the green pixels 10G, and the blue pixels 10B). In this case, note that the quantum dots are formed so as to generate the emission light of a wavelength longer than that of the excitation light L0, on the basis of the excitation light L0, as described above. Consequently, the light emitting layer 15 (or the red light emitting layers 15R, the green light emitting layers 15G, and the blue light emitting layers 15B) is formed on the light modulation element 14. Through the above processing, the display device 1 illustrated in
In the above display device 1, the laser light L0 is emitted, as the excitation light, from the light source section (or the laser light source 11, the reflection plate 121, the light guide plate 122, the diffuser plate 123, and the light modulation element 14) for each of the pixels (or the red pixels 10R, the green pixels 10G, and the blue pixels 10B), for example, as illustrated in
In more detail, the laser light (excitation light) L0 emitted from the laser light source 11 enters the light modulation element 14 through the light guide plate 122, the reflection plate 121, and the diffuser plate 123. The laser light L0 is modulated in this light modulation element 14 for each pixel, and then, the modulated light L0 is emitted to the light emitting layer 15. In this way, the luminance of the excitation light L0 emitted to the light emitting layer 15 is controlled for each pixel. For example, referring to an example illustrated in
The above display device 1 that uses the laser light (excitation light) L0 and the light emitting layer 15 containing the quantum dots provides, for example, the following advantages, in comparison with an existing, typical liquid crystal display device. The excitation light L0 is coupled to the light guide plate 122 efficiently, due to the directivity of the laser light L0, and any color filter is unnecessary. This decreases the optical loss, thereby improving the display luminance and achieving the low power consumption. In addition, the viewing angle property is improved (or the viewing angle dependency is suppressed), due to the merit of the self-light emitting type display device. Furthermore, since it is possible for the laser light L0 be driven with a short pulse, and quantum dots have a short fluorescence lifetime, a high speed operation, such as an operation at several nanoseconds to several hundred microseconds is realized. In addition, this high speed operation enhances a property of reproducing a moving image. For example, even when the display device 1 is applied to a 3D display device employing a time division type, the display device 1 also exhibits the excellent moving image reproduction property. Moreover, the laser light source L0 is used as the excitation light, and therefore, the spectrum of the emission light L1 (the red emission light L1r, the green red emission light L1g, or the blue red emission light L1b) has a narrow full width at half maximum (FWHM). This realizes display of the wide color gamut (or a display device having the high color reproducibility).
In this embodiment, in performing a display operation as described above, the quantum dots contained in the light emitting layer 15 generate the emission light L1 whose wavelength is longer than the excitation light L0, on the basis of the excitation light L0. In more detail, the quantum dots contained in each red light emitting layer 15R generate the red emission light L1r of a relatively long wavelength, on the basis of the excitation light L0 of a relatively short wavelength (or make a wavelength conversion from the excitation light L0 to the red emission light L1r). The quantum dots contained in each green light emitting layer 15G generate the green emission light L1g of a relatively long wavelength, on the basis of the excitation light L0 of a relatively short wavelength (or make a wavelength conversion from the excitation light L0 to the green emission light L1g). The quantum dots contained in each blue light emitting layer 15B generate the blue emission light L1b of a relatively long wavelength, on the basis of the excitation light L0 of a relatively short wavelength (or make a wavelength conversion from the excitation light L0 to the blue emission light L1b).
In this embodiment, as a result of the above function, the wavelength conversion is made from the excitation light L0 to the emission light L1 with a simpler configuration, for example, in comparison with, rather, a case where a wavelength conversion is made from excitation light of a longer wavelength to emission light of a shorter wavelength (a wavelength conversion is made employing, for example, a second harmonic generation (SHG)), and the like.
Here, before explaining a detailed operation of generating the emission light L1 with the quantum dots (or a detailed operation of a wavelength conversion from the excitation light L0 to the emission light L1) as described above, a description will be given of a principle of an electron energy transition regarding quantum dots.
First, with regard to the movement of a free electron in a one-dimensional region which is confined within an excessively small area like a quantum dot, a potential energy “U” of the free electron is 0 (U=0). Accordingly, the Schrodinger expression is given by the following expression (1).
E·ψ=−h
2/(8π2m)·(nabla)2ψ (1)
In this case, a wave function and electron energy that satisfy this expression are given by expressions (2) and (3), respectively.
Wave function:ψ=A·sin(nπx/L)(n: an integer of equal to or more than 1) (2)
Electron energy:En=(nh)2/(8 mL2)(n: an integer of equal to or more than 1) (3)
(A: a constant of the amplitude of a standing wave, L: the size of a quantum dot, n: a principal quantum number, x: the position of an electron (0<x<L), h: a Planck's constant, and m: the effective mass of an electron)
As described above, “n” denotes the principal quantum number, and is an integer of other than 1 (equal to or more than 1). Therefore, the energy of such an electron has the following property.
(A) The energy of an electron is determined by the size of a region in which an electron is confined, and is inversely proportional to the square of the size.
(B) The energy of an electron is not changed continuously, but discretely in accordance with the principal quantum number.
With regard to the change (transition) in the energy of an electron confined within a quantum dot, as is evident from (A), the energy of an electron within a quantum dot is determined by fabricating the quantum dot of a preset size. In addition, as is evident from (B), the energy of an electron within the quantum dot is changed discretely, and therefore, the absorption energy of light is also discrete.
In accordance with the above principle, each quantum dot contained in the light emitting layer 15 according to this embodiment performs an operation of generating the emission light L1 (or an operation of the wavelength conversion from the excitation light L0 to the emission light L1) by undergoing processes, concretely, such as those illustrated in Parts (A) to (C) of
Specifically, first, during an excitation process illustrated in Part (A) of
In this case, it is preferable for the difference in energy between the quantum level having a principal quantum number “n” of equal to/more than 2 (n≧2) and the quantum level in the valence band during the excitation process to be substantially equal (desirably, equal) to the energy of the excitation light L0 (for example, so as to fall within a wavelength range of ±10 nm). This is because, in this case, the absorption rate, especially for the excitation light L0, of the light emitting layer 15 containing the quantum dots increases, so that the emission light of high luminance is realized, even when the light emitting layer 15 is formed of a thin film. In view of this, it can be said that using laser light having an extremely narrow wavelength range as the excitation light L0 is desirable as in this embodiment.
In Example illustrated in Parts (A) to (C) of
Consequently, in Example, the spectrum of each of the red emission light L1r, the green emission light L1g, and the blue emission light L1b exhibits a high emission intensity (or high luminance) and a narrow FWHM, for example, as illustrated in Part (A) of
In contrast, in Comparative example illustrated in Part (B) of
As described above, in this embodiment, the quantum dots included in the light emitting layer 15 (or the red light emitting layers 15R, the green light emitting layers 15G, and the blue light emitting layer 15B) generate the emission light L1 (L1r, L1g, and L1b) whose wavelength is longer than the excitation light L0, on the basis of the excitation light L0. This achieves a wavelength conversion from the excitation light L0 to the emission light L1 with a simple configuration. Therefore, it is possible to facilitate the improvement of the utilization efficiency of light.
Moreover, the polarization direction of the laser light L0 emitted from the laser light source 11 is substantially aligned with the polarization axis (light transmitting axis) of the incident side polarization plate 141A. This increases the light transmission factor of the incident side polarization plate 141A, thus decreasing the optical loss. Consequently, the quantum dots contained in the light emitting layer 15 which the excitation light L0 is to enter after entering the incident side polarization plate 141A generates the emission light L1 efficiently. This enables the display device 1 to exhibit a higher luminance and lower power consumption.
Next, a description will be given of application examples of the above display device according to the embodiment, with reference to
Up to this point, the technique according to an embodiment of the present disclosure has been described by giving the embodiment and the application examples. However, the technique according to an embodiment of the present disclosure is not limited to this embodiment and the like, and various modifications are possible.
For example, in the above embodiment and the like, the cases have been described, where the light emitting layer is composed of multi-colored light emitting layers that are color-coded for each pixel, and the quantum dots in the individual multi-colored light emitting layers generate emission light beams of different wavelengths, on the basis of the excitation light. However, the technique according to an embodiment of the present disclosure is not limited to these cases. Specifically, this technique is also applicable to the case where the light emitting layer is composed of single-colored light emitting layers.
In the above embodiment and the like, the case has been described, where the light source section that emits the excitation light for each pixel is configured by the laser light sources (semiconductor lasers or the like) and the light modulation element (liquid crystal element and the like). However, the configuration of the light source section is not limited thereto, but may be another one.
For example, the laser light source is not limited to a semiconductor laser, but a laser light source of another type may be used instead. Specifically, for example, an Ar+ gas laser source (having an oscillation wavelength of 457 nm) may be used. In addition, laser light emitted from a semiconductor or gas laser light source may be subjected to a wavelength conversion by using a second harmonic generator (SHG), so that light of a shorter wavelength is generated and used as the excitation light. In this case, for example, an AlGaAs semiconductor laser (having an oscillation wavelength of 840 nm) and a SHG made of LiNbO3 may be used to generate the excitation light having a wavelength of approximately 420 nm.
The light source may not be a laser light source, as long as a light source emits the excitation light. However, using a laser light source, which emits the excitation light having a narrow FWHM and high directivity, is considered to be more desirable. This is because such laser light is absorbed more readily into each quantum dot having a narrow absorption wavelength range, and is coupled more efficiently to the light guide plate.
The configuration of the light modulation element composed of a liquid crystal element is not limited to that described in the above embodiment, but may be another one. For example, the incident side polarization plate 141A may not be provided, and therefore, only the output side polarization plate 141B may be used. This is because, for example, when the laser light is used as the excitation light, it is possible to decrease the optical loss to a certain extent without using the incident side polarization plate, due to the strongly polarized nature of the laser light. In addition, the light modulation element may be any light modulation element other than a liquid crystal element.
Accordingly, it is possible to achieve at least the following configurations from the above-described example embodiments, the application examples, and the modifications of the disclosure.
(1) A display device, including:
a light source section emitting excitation light for each pixel; and
a light emitting layer including a quantum dot and emitting emission light for each of the pixels, the quantum dot generating, based on the excitation light, the emission light having a wavelength longer than a wavelength of the excitation light.
(2) The display device according to (1), wherein, in the quantum dot:
during an excitation, an electron positioned in a valence band is excited to a quantum level having a principal quantum number of equal to or more than two in a conduction band, by obtaining energy of the excitation light;
during a relaxation, the electron having been excited to the quantum level having the principal quantum number of equal to or more than two is relaxed to an quantum level having a principal quantum number of one; and
during a recombination, the emission light of the longer wavelength is emitted that corresponds to a difference in energy between the quantum level having the principal quantum number of one and the quantum level in the valence band.
(3) The display device according to (2), wherein the difference in energy between the quantum level having the principal quantum number of equal to or more than two and the quantum level in the valence band is substantially equal to the energy of the excitation light.
(4) The display device according to any one of (1) to (3), wherein the light source section includes:
a laser light source emitting laser light as the excitation light; and
a light modulation element modulating the laser light for each of the pixels.
(5) The display device according to (4), wherein the light modulation element includes a liquid crystal element, and the liquid crystal element includes:
a pair of substrates that are opposed to each other;
a liquid crystal layer interposed and sealed between the pair of substrates;
an incident side polarization plate disposed on a substrate of the pair of substrates that is closer to the laser light source; and
an output side polarization plate disposed on a substrate of the pair of substrates that is closer to the light emitting layer.
(6) The display device according to (5), wherein a polarization direction of the laser light is substantially aligned with a polarization axis of the incident side polarization plate.
(7) The display device according to any one of (4) to (6), wherein the laser light source includes a semiconductor laser.
(8) The display device according to any one of (1) to (7), wherein
the light emitting layer includes multi-colored light emitting layers that are color-coded for each of the pixels, and
the quantum dot in each of the multi-colored light emitting layers generates, based on the excitation light, the emission light having the wavelength that is different between the multi-colored light emitting layers.
(9) An electronic apparatus with a display device, the display device including:
a light source section emitting excitation light for each pixel; and
a light emitting layer including a quantum dot and emitting emission light for each of the pixels, the quantum dot generating, based on the excitation light, the emission light having a wavelength longer than a wavelength of the excitation light.
(10) The electronic apparatus according to (9), wherein, in the quantum dot:
during an excitation, an electron positioned in a valence band is excited to a quantum level having a principal quantum number of equal to or more than two in a conduction band, by obtaining energy of the excitation light;
during a relaxation, the electron having been excited to the quantum level having the principal quantum number of equal to or more than two is relaxed to an quantum level having a principal quantum number of one; and
during a recombination, the emission light of the longer wavelength is emitted that corresponds to a difference in energy between the quantum level having the principal quantum number of one and the quantum level in the valence band.
(11) The electronic apparatus according to (10), wherein the difference in energy between the quantum level having the principal quantum number of equal to or more than two and the quantum level in the valence band is substantially equal to the energy of the excitation light.
(12) The electronic apparatus according to any one of (9) to (11), wherein the light source section includes:
a laser light source emitting laser light as the excitation light; and
a light modulation element modulating the laser light for each of the pixels.
(13) The electronic apparatus according to (12), wherein the light modulation element includes a liquid crystal element, and the liquid crystal element includes:
a pair of substrates that are opposed to each other;
a liquid crystal layer interposed and sealed between the pair of substrates;
an incident side polarization plate disposed on a substrate of the pair of substrates that is closer to the laser light source; and
an output side polarization plate disposed on a substrate of the pair of substrates that is closer to the light emitting layer.
(14) The electronic apparatus according to (13), wherein a polarization direction of the laser light is substantially aligned with a polarization axis of the incident side polarization plate.
(15) The electronic apparatus according to any one of (12) to (14), wherein the laser light source includes a semiconductor laser.
(16) The electronic apparatus according to any one of (9) to (15), wherein
the light emitting layer includes multi-colored light emitting layers that are color-coded for each of the pixels, and
the quantum dot in each of the multi-colored light emitting layers generates, based on the excitation light, the emission light having the wavelength that is different between the multi-colored light emitting layers.
(17) A method of manufacturing a display device, the method including:
forming a light source section that emits excitation light for each pixel; and
forming, using a quantum dot, a light emitting layer that emits emission light for each of the pixels, the quantum dot being configured to generate, based on the excitation light, the emission light having a wavelength longer than a wavelength of the excitation light.
(18) The method of manufacturing the display device according to (17), wherein, in the quantum dot:
during an excitation, an electron positioned in a valence band is excited to a quantum level having a principal quantum number of equal to or more than two in a conduction band, by obtaining energy of the excitation light;
during a relaxation, the electron having been excited to the quantum level having the principal quantum number of equal to or more than two is relaxed to an quantum level having a principal quantum number of one; and
during a recombination, the emission light of the longer wavelength is emitted that corresponds to a difference in energy between the quantum level having the principal quantum number of one and the quantum level in the valence band.
(19) The method of manufacturing the display device according to (18), wherein the difference in energy between the quantum level having the principal quantum number of equal to or more than two and the quantum level in the valence band is substantially equal to the energy of the excitation light.
(20) The method of manufacturing the display device according to any one of (17) to (19), wherein the forming the light source section includes:
forming a laser light source that emits laser light as the excitation light; and
forming a light modulation element that modulates the laser light for each of the pixels.
(21) The method of manufacturing the display device according to (20), wherein forming a liquid crystal element as the light modulation element includes:
forming a pair of substrates that are opposed to each other;
forming a liquid crystal layer interposed and sealed between the pair of substrates;
forming an incident side polarization plate disposed on a substrate of the pair of substrates that is closer to the laser light source; and
forming an output side polarization plate disposed on a substrate of the pair of substrates that is closer to the light emitting layer.
(22) The method of manufacturing the display device according to (21), wherein a polarization direction of the laser light is substantially aligned with a polarization axis of the incident side polarization plate.
(23) The method of manufacturing the display device according to any one of (20) to (22), wherein the laser light source includes a semiconductor laser.
(24) The method of manufacturing the display device according to any one of (17) to (23), wherein
the light emitting layer includes multi-colored light emitting layers that are color-coded for each of the pixels, and
the quantum dot in each of the multi-colored light emitting layers generates, based on the excitation light, the emission light having the wavelength that is different between the multi-colored light emitting layers.
The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2011-172745 filed in the Japan Patent Office on Aug. 8, 2011, the entire content of which is hereby incorporated by reference.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-172745 | Aug 2011 | JP | national |
