JP2018054748A - Light source device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device and display device that can suppress deterioration of a quantum dot due to heat.SOLUTION: A light source device 100 according to one embodiment of the present invention comprises a structure body 110 that includes a dispersion medium 113 having an anisotropy in thermal conductivity, and a quantum dot 112 having the dispersion medium dispersed. An axis high in the thermal conductivity of the dispersion medium directs at a direction where thermal resistance of the structure body is the lowest. Since the thermal conductivity when the dispersion medium is oriented is high along a prescribed axis, the axis high in the thermal conductivity of the structure body of the dispersion medium is made to direct in the direction where the thermal resistance is the lowest, which in turn increases an amount of radiation from the structure body.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a light source device and a display device.

  In recent years, in order to provide a liquid crystal display device capable of displaying an image with good color reproducibility, development of a technique for increasing the color purity of incident light on the liquid crystal display element has been demanded. As an example, a technique using quantum dots has been developed. A quantum dot is a fluorescent substance, and when excitation light from a light source such as a light emitting diode (LED) is incident, it generates light having a wavelength longer than the wavelength of the excitation light. The wavelength of light generated by the quantum dots can be adjusted by changing the type and particle size of the quantum dots. For example, blue light from an LED is used as excitation light, and the quantum dots are configured to generate green light and red light having a narrow half-value width when the blue light is incident. Thereby, the highly efficient light source which can produce | generate the light of the narrow wavelength range corresponding to the three primary colors of light using a quantum dot is realizable.

  Quantum dots are susceptible to degradation when exposed to water, oxygen and heat. The technique described in Patent Document 1 seals quantum dots dispersed in a resin or an organic solvent in a container having a barrier property against water and oxygen. With such a configuration, it is possible to improve the reliability by suppressing the deterioration of the light source device including the quantum dots.

JP, 2006-76634, A Japanese Unexamined Patent Publication No. 2015-233057

  The container that seals the quantum dots easily accumulates heat generated by non-radiative deactivation of the quantum dots themselves. For this reason, the quantum dots may be deteriorated due to the heat accumulated in the container. However, although the technique described in Patent Document 1 can suppress deterioration due to water and oxygen, it does not consider deterioration due to heat.

  The present invention has been made in view of the above problems, and an object thereof is to provide a light source device and a display device that can suppress deterioration of quantum dots due to heat.

  One embodiment of the present invention is a light source device including a dispersion medium having anisotropic thermal conductivity and a structure including quantum dots dispersed in the dispersion medium, and the thermal conductivity of the dispersion medium. The high axis is directed to the direction in which the thermal resistance of the structure is lowest.

  According to the present invention, in order to appropriately set the axis with high thermal conductivity of the dispersion medium so that the thermal resistance of the structure including the quantum dots is directed to the lowest direction, the amount of heat released from the structure including the quantum dots is reduced. It is possible to suppress the deterioration of the quantum dots due to heat.

It is a front view of the display apparatus which concerns on 1st Embodiment. It is sectional drawing of the display apparatus which concerns on 1st Embodiment. It is sectional drawing of the quantum dot structure which concerns on 1st Embodiment. It is a schematic diagram which shows the orientation of the dispersion medium which concerns on 1st Embodiment. It is a schematic diagram which shows the relationship between the orientation of the dispersion medium which concerns on 1st Embodiment, and the structure of a quantum dot structure. It is a front view of the display apparatus which concerns on 2nd Embodiment. It is a schematic diagram of the light source device which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments. In the drawings described below, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

(First embodiment)
FIG. 1 is a front view of a display device 10 according to the present embodiment. The display device 10 includes a liquid crystal panel 20, a light source device 100 provided along the back surface of the liquid crystal panel, and a frame 30 that supports the liquid crystal panel 20 and the light source device 100. In FIG. 1, the liquid crystal panel 20 is shown to pass through the light source device 100 on the back side for visibility. The number and size of each part included in the display device 10 shown in FIG. 1 does not reflect the actual configuration, and may be arbitrarily designed according to the actual mounting method.

  The light source device 100 is a direct type backlight unit, and irradiates the liquid crystal panel 20 with light from the back side of the liquid crystal panel 20. A detailed configuration of the light source device 100 will be described later with reference to FIGS. The liquid crystal panel 20 has a known configuration including an electric circuit such as a liquid crystal layer, a polarizing plate, a color filter, and a thin film transistor (TFT). The liquid crystal panel 20 displays a desired image by controlling the transmittance of light from the light source device 100 for each pixel through an electric circuit. The frame 30 is configured using resin, metal, or the like, and supports the liquid crystal panel 20 and the light source device 100. Inside the frame 30, electrical wiring to the liquid crystal panel 20 and the light source device 100 is disposed. In the present embodiment, a direct type backlight unit is illustrated as a backlight unit system, but an edge light system may be used.

  FIG. 2 is a cross-sectional view of the display device 10 as viewed from line AA in FIG. The light source device 100 includes a light source unit 120 that generates light of a predetermined wavelength, and a quantum dot structure 110 that converts the wavelength of light from the light source unit 120.

  The light source unit 120 includes a light emitting element 121, a substrate 122, and a frame 123. The light emitting element 121 generates light having a predetermined wavelength and irradiates the light toward the liquid crystal panel 20. The light emitting element 121 is electrically connected to an electric wiring (not shown), and generates light using electric power applied through the electric wiring. The wavelength of light generated by the light emitting element 121 is, for example, a blue light wavelength region (about 380 nm to 500 nm) or an ultraviolet light wavelength region (about 10 nm to 380 nm). As the light emitting element 121, any light emitting element such as a light emitting diode (LED) or an organic light emitting diode (OLED) may be used. The light from the light-emitting element 121 enters the quantum dot structure 110 described later as excitation light, so that the light source device 100 can generate light in a narrow wavelength region corresponding to the three primary colors of light.

  The frame 123 has a concave shape, and the light emitting element 121 is supported on the bottom surface of the shape. The shape of the frame 123 is not limited to this, and may be any shape. The frame 123 may be configured using any material such as resin, metal, and semiconductor. The frame 123 may be omitted, and in that case, the light emitting element 121 may be directly supported on the substrate 122.

  The substrate 122 extends in parallel with the surface of the liquid crystal panel 20 and supports the plurality of light emitting elements 121 and the frame 123. In the present embodiment, a predetermined number of light emitting elements 121 and frames 123 are arranged on the substrate 122 in a grid pattern and at equal intervals. The number and arrangement of the light emitting elements 121 and the frames 123 may be arbitrarily set according to the configuration of the display device 10. The substrate 122 may be configured using any material such as resin, metal, and semiconductor.

  The quantum dot structure 110 is located between the back surface of the liquid crystal panel 20 and the light source unit 120, and is interposed in the optical path of light emitted from the light source unit 120 to the back surface of the liquid crystal panel 20. That is, the light from the light source unit 120 is applied to the back surface of the liquid crystal panel 20 through the quantum dot structure 110.

  FIG. 3 is a detailed cross-sectional view of the quantum dot structure 110 viewed from the line AA in FIG. The quantum dot structure 110 includes a sealed container 111, and quantum dots 112 and a dispersion medium 113 sealed in the sealed container 111.

  The sealed container 111 is a container having an internal space isolated from the external space (that is, the atmosphere), and uses any material such as glass or resin that transmits at least light in the visible light wavelength region (about 380 nm to 780 nm). Configured. In order to suppress the deterioration of the quantum dots 112 due to water and oxygen, it is desirable that the sealed container 111 is configured using a material having a barrier property against water and oxygen.

  In the present embodiment, the sealed container 111 is configured as a glass cell formed using glass having a high barrier property against water and oxygen. Specifically, the sealed container 111 has a rectangular columnar structure in which two glass rectangular plates parallel to each other are opposed to each other with a predetermined interval through a glass side wall. Light from the light source unit 120 enters the two glass rectangular plates perpendicularly. The structure of the sealed container 111 is not limited to that shown here, and a known one may be used (see, for example, Patent Document 2). The shape of the sealed container 111 may be an arbitrary shape such as a cylindrical shape. At least a part of the wall surface constituting the sealed container 111 may be a curved surface instead of a flat surface.

  The quantum dot 112 (also referred to as colloidal quantum dot) is a nanoscale material having optical properties according to quantum mechanics, and has a particle size of about 1 nm to 100 nm, preferably 1 nm to 50 nm, more preferably 1 nm to 20 nm. Semiconductor particles. The quantum dot 112 absorbs a photon having energy larger than the band gap (energy difference between the valence band and the conduction band) and emits light having a wavelength corresponding to the particle diameter. Therefore, the quantum dot 112 has a property of absorbing light having a predetermined wavelength or less, and can generate light having a desired wavelength by adjusting the particle diameter. In the present embodiment, the quantum dots 112 are spherical as shown in FIG. 3, but are not limited to this and may have any shape.

  The quantum dot 112 includes at least one semiconductor material. As semiconductor materials for the quantum dots 112, group IV elements, group II-VI compounds, group II-V compounds, group III-VI compounds, group III-V compounds, group IV-VI compounds, group I -III-VI compounds, II-IV-VI compounds, II-IV-V compounds, etc. may be used. Specifically, as the semiconductor material of the quantum dots 112, ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, MgS, MgSe, GaAs, GaN, GaP, GaSe, GaSb, HgO, HgS, HgSe, HgTe InAs, InN, InP, InSb, AlAs, A1N, A1P, AlSb, TiN, TiP, TiAs, TiSb, PbO, PbS, PbSe, PbTe, Ge, Si, and the like can be used. The material of the quantum dot 112 is not limited to the material shown here, and any material may be used as long as the function of the quantum dot can be exhibited.

  When the light generated by the light source unit 120 is blue light, the first quantum dot 112 having a light emission center wavelength in the wavelength region of green light (about 510 nm to 610 nm, preferably 520 nm to 580 nm), and red A second quantum dot 112 having an emission center wavelength in the wavelength region of light (about 600 nm to 700 nm, preferably 610 nm to 680 nm) is used in combination. That is, the blue light generated by the light source unit 120 functions as excitation light for the quantum dots 112 and also functions as visible light emitted from the light source device 100. In the present embodiment, a light source having an emission spectrum with three maxima of blue, green, and red has been shown, but the combination of the emission center wavelength of quantum dots and quantum dots is not limited to this, and any combination is used. Good.

  When the light generated by the light source unit 120 is ultraviolet light, the first quantum dots 112 having the emission center wavelength in the wavelength region of green light and the second quantum having the emission center wavelength in the wavelength region of red light. The dot 112 is used in combination with the third quantum dot 112 having the emission center wavelength in the blue light wavelength region. That is, the ultraviolet light generated by the light source unit 120 functions as excitation light for the quantum dots 112.

  The quantum dots 112 may have a core-shell type structure including a core including at least one semiconductor material and a shell including at least one semiconductor material. Specifically, quantum dots 112 having CdSe as a core and CdZnS as a shell, CdZnSe as a core, quantum dots 112 having CdZnS as a shell, quantum dots 112 having CdS as a core and CdZnS as a shell, and the like can be used.

  In the present embodiment, since the relationship described below is set between the structure of the quantum dot structure 110 and the axis having high thermal conductivity of the dispersion medium 113, high heat dissipation of the quantum dot structure 110 is realized. be able to. The dispersion medium 113 is a liquid or solid medium having anisotropy in thermal conductivity, and disperses the quantum dots 112. Anisotropy in thermal conductivity means that the thermal conductivity is higher in a specific direction than in other directions. Further, since the shape of the quantum dot structure 110 is usually not a sphere, the thermal resistance is anisotropic. The anisotropy of the thermal resistance means that the thermal resistance in each direction is not constant in the quantum dot structure 110, and the thermal resistance is low along a specific direction as compared with other directions.

  The light source device 100 according to the present embodiment appropriately sets the axis with high thermal conductivity of the dispersion medium 113 based on the thermal resistance in each direction of the quantum dot structure 110, thereby releasing the light from the quantum dot structure 110. The amount of heat is increased, and deterioration of the quantum dots 112 due to heat is suppressed.

  Specifically, a liquid crystalline polymer (also referred to as a liquid crystal polymer or a polymer liquid crystal) is used as the dispersion medium 113. The liquid crystalline polymer is a polymer compound containing a liquid crystal structure (that is, a mesogenic group) in at least one of a main chain and a side chain. Those having a liquid crystal structure in the main chain are called main chain type liquid crystalline polymers, and those having a side chain having a liquid crystal structure are called side chain type liquid crystalline polymers. Since the mesogenic group has a rod-like or plate-like rigid structure, it imparts liquid crystal properties to the polymer compound. As the mesogenic group, a known structure such as a biphenyl group or a phenylbenzoate group may be used. In this embodiment, only the liquid crystalline polymer is used as the dispersion medium 113, but a liquid crystal polymer added with an optional additive such as a dilution monomer or an organic solvent may be used. Further, the liquid crystalline polymer may have a polymerizable group, or may be a liquid crystalline polymer obtained by polymerizing a liquid crystalline molecule having a polymerizable group.

  FIG. 4 is a schematic diagram showing the orientation of the dispersion medium 113 according to the present embodiment. In FIG. 4, only the liquid crystal structure is shown in the dispersion medium 113, and portions other than the liquid crystal structure are omitted. The orientation of the dispersion medium 113 is the average orientation of the major axis of the liquid crystal structure (mesogen group) contained in the dispersion medium 113 which is a liquid crystalline polymer. In FIG. 4, the direction B of orientation of the dispersion medium 113 is indicated by an arrow.

  In this embodiment, since the dispersion medium 113 is oriented along a predetermined direction B (predetermined axis), the liquid crystal structures of the dispersion medium 113 are aligned, and quantum dots are arranged between the liquid crystal structures of the dispersion medium 113. 112 is distributed. In the manufacturing process of the quantum dot structure 110, the liquid crystal structure of the dispersion medium 113 is aligned by an arbitrary method, and the orientation of the dispersion medium 113 is set. For example, the dispersion medium 113 may be oriented by applying an external force such as a magnetic field, electric field, stretching force or shear stress to the dispersion medium 113 or by providing an orientation film on the inner wall of the sealed container 111. Further, the dispersion medium 113 may be spontaneously aligned by introducing a predetermined structure that promotes spontaneous alignment such as an ionic group into the liquid crystal structure.

  When the liquid crystal structure of the dispersion medium 113 is aligned along the predetermined direction B, phonon scattering is reduced in the dispersion medium 113. In general, the smaller the phonon scattering, the higher the thermal conductivity. Therefore, the thermal conductivity along one direction of the dispersion medium 113 is higher as the direction is closer to the orientation direction B, that is, the smaller the angle formed between the direction and the orientation direction B is. In other words, the thermal conductivity along the direction B (predetermined axis) of the orientation of the dispersion medium 113 is the highest compared to directions other than the direction B.

  Although either a nematic phase or a smectic phase may be used as the liquid crystal structure of the dispersion medium 113, the smectic phase is more preferable because it has a higher thermal conductivity than the nematic phase.

  FIGS. 5A and 5B are schematic views showing the relationship between the orientation of the dispersion medium 113 and the structure of the quantum dot structure 110 according to the present embodiment. 5A and 5B, the structure of the quantum dot structure 110 is different.

  As described above, the shape of the sealed container 111 of the quantum dot structure 110 is a quadrangular prism shape. As shown in FIG. 5A, in the sealed container 111, the height h along a predetermined direction C (here, the incident direction of light from the light source unit 120) is a width along a direction perpendicular to the direction C. smaller than w. In this case, the thermal resistance along the direction C (that is, the direction in which the thickness is the smallest) of the quantum dot structure 110 is the smallest compared to the directions other than the direction C. In other words, the quantum dot structure 110 easily radiates heat along the direction C where the thickness is the smallest. In the form of FIG. 5A, the orientation of the dispersion medium 113 is such that the orientation direction B of the dispersion medium 113 (that is, the axis having high thermal conductivity) is close to the direction C where the thickness of the quantum dot structure 110 is the smallest. Is set, the amount of heat released from the quantum dot structure 110 is increased.

  In the form shown in FIG. 5B, a heat sink 114 as a heat radiating member is provided on at least a part of the side wall of the sealed container 111. In such a configuration, the thermal resistance along the direction D toward the side wall on which the heat sink 114 is provided is smaller than that in the direction other than the direction D, regardless of the thickness as shown in FIG. Smallest. In other words, the quantum dot structure 110 easily radiates heat along the direction D toward the heat sink 114. 5B, the orientation of the dispersion medium 113 is set so that the orientation direction B of the dispersion medium 113 (that is, the axis having high thermal conductivity) is close to the direction D toward the heat sink 114 of the quantum dot structure 110. By setting, the amount of heat released from the quantum dot structure 110 is increased.

  The thermal resistance in each direction of the quantum dot structure 110 is determined by the material and shape of the quantum dot structure 110 and the presence or absence of a heat dissipation member. Generally, the thermal resistance in each direction of the quantum dot structure 110 is not constant, and the thermal resistance is lowest along a specific direction. When the shape of the quantum dot structure 110 is complicated and there are a plurality of minimum values in the thermal resistance for each direction (that is, when there are a plurality of directions having lower thermal resistance than other adjacent directions), Each local minimum value is regarded as the direction with the lowest thermal resistance. In the quantum dot structure 110 according to the present embodiment, the axis of high thermal conductivity of the dispersion medium 113 is close to the direction in which the thermal resistance of the quantum dot structure 110 is the lowest, in other words, the thermal conductivity of the dispersion medium 113. The orientation of the dispersion medium 113 is set so that the higher axis is oriented in the direction in which the thermal resistance of the quantum dot structure 110 is lowest. Specifically, it is desirable that the angle formed between the axis with high thermal conductivity of the dispersion medium 113 and the direction with the lowest thermal resistance of the quantum dot structure 110 is set to 0 degree or more and less than 45 degrees. With such a configuration, an effect of increasing the heat radiation amount from the quantum dot structure 110 can be obtained.

  It is preferable to use a liquid crystalline polymer as the dispersion medium 113 having anisotropy in thermal conductivity because the alignment can be easily adjusted and the efficiency of heat dissipation can be easily improved. In the present embodiment, a magnetic field is used to set the orientation of the dispersion medium 113 that is a liquid crystalline polymer. Specifically, the quantum dots 112 are added and mixed while the dispersion medium 113 that is a liquid crystalline polymer is at a high temperature, and a magnetic field is applied so as to set the orientation of the dispersion medium 113 in a target direction. Thereafter, the dispersion medium 113 is cooled in a state where a magnetic field is applied, and the application of the magnetic field is terminated. Thereby, the orientation of the dispersion medium 113 can be maintained in a predetermined direction.

  In order to set the orientation of the dispersion medium 113, in addition to the magnetic field, an external force such as an electric field, stretching force, and shear stress may be applied so as to set the orientation of the dispersion medium 113 in a target direction. In addition, an alignment film for setting the orientation of the dispersion medium 113 in a target direction may be provided on the inner wall of the sealed container 111. In addition, a predetermined structure that promotes spontaneous alignment such as ionic groups may be introduced into the liquid crystal structure of the dispersion medium 113 so that the alignment of the dispersion medium 113 is performed in a desired direction. The orientation of the dispersion medium 113 that is a liquid crystalline polymer may be set by any other method.

  As the dispersion medium 113 having anisotropic thermal conductivity, in addition to the liquid crystalline polymer, any substance capable of adjusting the direction of high thermal conductivity may be used. As the dispersion medium 113 having anisotropy in thermal conductivity, substances having shapes with different major and minor axes can be used. For example, an organic compound such as a resin or an inorganic compound such as glass, which is molded into a rod-like or needle-like shape. By using a substance having a shape in which the major axis and the minor axis are different, the direction in which the thermal conductivity is high like the liquid crystalline polymer can be adjusted. In order to set the orientation of such a substance, an external force such as a magnetic field, an electric field, or a stretching force may be used as described above.

  In particular, in the configuration in which the quantum dots 112 are sealed in the sealed container 111 as described above, the heat dissipation is poor, and the problem that the quantum dots 112 deteriorate due to heat is likely to occur. Therefore, the effect of this embodiment can be significantly obtained. However, the quantum dot structure 110 is not limited to the specific configuration described above, and may be a film-like configuration in which the sealed container 111 is omitted.

  In the present embodiment, the orientation of the dispersion medium 113 that disperses the quantum dots 112 is set so that the axis with high thermal conductivity of the dispersion medium 113 is close to the direction in which the thermal resistance of the quantum dot structure 110 is the lowest. . With such a configuration, the amount of heat released from the quantum dot structure 110 is increased, and heat generated due to non-radiative deactivation of the quantum dots 112 is prevented from accumulating in the quantum dot structure 110. As a result, deterioration of the quantum dots 112 due to heat can be suppressed, and the reliability of the light source device 100 can be improved.

(Example)
As an example, an acceleration test was performed on a quantum dot structure 110 including a dispersion medium 113 that is a liquid crystalline polymer having a structure represented by the following formula (1) and subjected to an alignment treatment. Further, as a comparative example, an acceleration test was performed on the quantum dot structure 110 that was not subjected to the alignment treatment using the same dispersion medium 113. The number average molecular weight of the liquid crystalline polymer having the structure represented by the formula (1) was 26000 g / mol, and the polydispersity of the molecular weight distribution was 1.53. Table 1 shows the results of measuring the thermal conductivity in the alignment direction after the alignment treatment for this liquid crystalline polymer.

  The quantum dot structure 110 was manufactured as follows. First, the sealed container 111 of the quantum dot structure 110 was filled with a mixture of the quantum dots 112 and the dispersion medium 113. Subsequently, while maintaining the quantum dot structure 110 at 130 ° C., which is higher than the liquid crystal-liquid transition temperature of the liquid crystalline polymer, 130 ° C., a magnetic field of 3.8 T is applied in the minor axis direction of the sealed container 111 ( That is, it was applied along the direction of the smallest thickness. Furthermore, the quantum dot structure 110 used as an example was obtained by lowering the temperature to room temperature under the condition of 1 ° C./min while applying the magnetic field.

  The presence / absence of orientation was determined from a two-dimensional diffraction image photographed with an X-ray beam incident perpendicularly to the magnetic field direction with an X-ray diffractometer (manufactured by Bruker, D8 DISCOVER, two-dimensional detector Vantec 500).

  As a condition for the acceleration test, the quantum dot structure 110 was placed on an LED having a central wavelength of 450 nm, and the LED was turned on at an environmental temperature of 85 degrees. The coordinates on the CIE1931 chromaticity diagram of the light that passed through the quantum dot structure 110 were measured for the state before the LED was turned on and the state after 70 hours had elapsed, and the chromaticity changes ΔCx and ΔCy between those states were calculated. . The chromaticity change ΔCx is the change amount of the x coordinate in the chromaticity diagram, and the chromaticity change ΔCy is the change amount of the y coordinate in the chromaticity diagram. The measurement results are shown in Table 1.

  As shown in Table 1, in the example in which the alignment treatment was performed, the thermal conductivity in the vertical direction was improved as compared with the comparative example in which the alignment treatment was not performed. And in the Example in which the alignment process was performed, the absolute value of chromaticity change (DELTA) Cx and (DELTA) Cy is smaller than the comparative example in which the alignment process is not performed. Therefore, it was confirmed that by performing the alignment treatment on the dispersion medium 113 that is a liquid crystalline polymer, a change in chromaticity after a long time was suppressed and reliability was improved.

(Second Embodiment)
In the first embodiment, the light source device 100 is a direct type backlight unit, but in the present embodiment, the light source device 200 is an edge type backlight unit. Except for the configuration of the light source device 200, the configuration is the same as that of the first embodiment.

  FIG. 6 is a front view of the display device 11 according to the present embodiment. The display device 11 includes a liquid crystal panel 20, a light source device 200 provided along an end surface of the liquid crystal panel, and a frame 30 that supports the liquid crystal panel 20 and the light source device 200. In FIG. 6, the frame 30 is shown to pass through the internal light source device 200 for visibility. The light from the light source device 200 is applied to the liquid crystal panel via a light guide plate (not shown) provided on the back side of the liquid crystal panel 20. In the present embodiment, the light source device 200 is provided only on the right end surface of the liquid crystal panel 20, but is provided on one or more of the upper end surface, the lower end surface, the left end surface, and the right end surface of the liquid crystal panel 20. Good.

  FIG. 7 is a schematic diagram of the light source device 200 according to the present embodiment. The light source device 200 includes a light source unit 220 that generates light of a predetermined wavelength, and a quantum dot structure 210 that converts the wavelength of light from the light source unit 220.

  The light source unit 220 includes the light emitting element 121 and the substrate 122 similar to those of the first embodiment, but the frame 123 is omitted. The substrate 122 extends parallel to the end face of the liquid crystal panel 20 and supports the plurality of light emitting elements 121. In the present embodiment, a predetermined number of light emitting elements 121 are arranged in a line on the substrate 122 at equal intervals. The number and arrangement of the light emitting elements 121 may be arbitrarily set according to the configuration of the display device 11.

  The quantum dot structure 210 includes a sealed container 211, and quantum dots 112 and a dispersion medium 113 similar to those of the first embodiment sealed in the sealed container 211. One sealed container 111 according to the first embodiment is provided corresponding to one light emitting element 121, but one sealed container 211 according to the present embodiment is provided corresponding to a plurality of light emitting elements 121. ing.

  The material of the sealed container 211 is the same as that of the first embodiment. The sealed container 211 has a rod-like shape extending in parallel with the end face of the liquid crystal panel 20. The quantum dot structure 210 is located between the end surface of the liquid crystal panel 20 and the light source unit 220, and is interposed in the optical path of light emitted from the light source unit 220 to the end surface of the liquid crystal panel 20. That is, light from the plurality of light emitting elements 121 included in the light source unit 220 is irradiated to the end surface of the liquid crystal panel 20 through the quantum dot structure 210.

  Since the shape of the sealed container 211 of the quantum dot structure 210 is a rod, the thickness of the sealed container 211 along the predetermined direction E (here, the incident direction of light from the light source unit 120) is the smallest. In this case, the thermal resistance along the direction E (that is, the direction in which the thickness is the smallest) of the quantum dot structure 210 is the smallest compared to the directions other than the direction E. In other words, the quantum dot structure 210 is likely to dissipate heat along the direction E where the thickness is the smallest. Therefore, in this embodiment, by setting the orientation of the dispersion medium 113 so that the orientation direction B of the dispersion medium 113 is close to the direction E in which the thickness of the quantum dot structure 210 is the smallest, Increase heat dissipation.

  Also in the display device 11 according to the present embodiment, by appropriately setting the orientation of the dispersion medium 113 as in the first embodiment, the amount of heat released from the quantum dot structure 210 is increased, and the quantum dots 112 due to heat are used. Can be prevented.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 Display apparatus 110 Quantum dot structure 112 Quantum dot 113 Dispersion medium

Claims (12)

A structure including a dispersion medium having anisotropic thermal conductivity and a quantum dot dispersed in the dispersion medium,
The light source device characterized in that the axis of high thermal conductivity of the dispersion medium is oriented in the direction in which the thermal resistance of the structure is lowest.   The light source device according to claim 1, wherein the axis of the dispersion medium is oriented in a direction in which the thickness is smallest in the structure.   The light source device according to claim 1, wherein the axis of the dispersion medium is oriented in a direction in which a heat dissipation member is provided in the structure.   The light source device according to claim 1, wherein the dispersion medium has the highest thermal conductivity along the direction of the axis.   5. The light source device according to claim 1, wherein the dispersion medium has a shape in which a length of a major axis is different from a length of a minor axis.   The light source device according to claim 1, wherein the dispersion medium is a liquid crystalline polymer.   The light source device according to claim 6, wherein the dispersion medium is a side chain type liquid crystalline polymer. The light source device according to claim 7, wherein the dispersion medium is a liquid crystalline polymer represented by Formula (1).

  The light source apparatus according to claim 1, wherein the axis of the dispersion medium is set by orienting the dispersion medium by applying a magnetic field to the structure. .   The light source device according to claim 1, wherein the structure further includes a container that seals the dispersion medium and the quantum dots.   The light source device according to claim 1, further comprising a light emitting element that emits light that excites the quantum dots toward the structure.   A display device comprising: the light source device according to claim 1; and a liquid crystal panel provided at a position irradiated with light from the light source device.

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