Display device and method for manufacturing display device

Abstract

The present invention improves performance of a display device. The display device comprises: a substrate; a light-emitting element provided on the substrate; a first lens provided so that light emitted from the light-emitting element is incident thereon, the first lens having a first refractive index; a quantum dot layer provided so as to cover the first lens; and a second lens provided so as to cover the quantum dot layer, the second lens having a second refractive index smaller than the first refractive index. The first lens is provided between the quantum dot layer and the light-emitting element.

Description

Display device and method for manufacturing the same

[0001] The present invention relates to a display device and a method for manufacturing the same.

[0002] Patent Document 1 (Japanese Patent Application Laid-Open No. 2023-155685) discloses a display device including an element substrate on which a plurality of light sources are arranged, a protective layer provided on the element substrate and covering the light sources, a color filter provided on the protective layer and having a plurality of color filters arranged corresponding to the light sources, a lens array provided on the color filter and having a plurality of microlenses arranged corresponding to the color filters, and a planarization layer provided on the lens array and covering the microlenses and having a refractive index lower than that of the microlenses.

[0003] Japanese Patent Application Laid-Open No. 2023-155685

[0004] However, it is necessary to further improve the performance of the display device. Therefore, it is an object to improve the performance of the display device.

[0005] Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.

[0006] A display device including a substrate, a light-emitting element provided on the substrate, a first lens provided so that light emitted from the light-emitting element is incident thereon and having a first refractive index, a quantum dot layer provided so as to cover the first lens, and a second lens provided so as to cover the quantum dot layer and having a second refractive index smaller than the first refractive index, wherein the first lens is provided between the quantum dot layer and the light-emitting element.

[0007] A method for manufacturing a display device, comprising: (a) a step of providing a light-emitting element on a substrate; (b) a step of sealing the light-emitting element with an insulating film; (c) a step of providing a first lens having a first refractive index on the insulating film; (d) a step of providing a quantum dot layer so as to cover the first lens; and (e) a step of providing a second lens having a second refractive index smaller than the first refractive index so as to cover the quantum dot layer.

[0008] Figure 1 is a cross-sectional view showing an example of a display device. Figure 2 is a plan view showing an example of a display device. Figure 3 is a cross-sectional view of a display device according to an example under consideration. Figure 4 is a cross-sectional view showing an example of a display device. Figure 5 is a cross-sectional view showing an example of a display device. Figure 6 is a cross-sectional view showing an example of a display device. Figure 7 is a cross-sectional view showing a method for manufacturing a display device. Figure 8 is a cross-sectional view showing a method for manufacturing a display device. Figure 9 is a cross-sectional view showing a method for manufacturing a display device. Figure 10 is a cross-sectional view showing a method for manufacturing a display device. Figure 11 is a cross-sectional view showing a method for manufacturing a display device. Figure 12 is a cross-sectional view showing a method for manufacturing a display device. Figure 13 is a cross-sectional view showing a method for manufacturing a display device. Figure 14 is a cross-sectional view showing a method for manufacturing a display device.

[0009] The embodiments of the present invention will be described below with reference to the drawings. Note that the disclosure is merely an example, and modifications that can be easily conceived by those skilled in the art while maintaining the spirit of the invention are naturally included within the scope of the present invention. Furthermore, the drawings may schematically represent the width, thickness, shape, etc., of each part in order to clarify the explanation, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and in each drawing, elements similar to those described above in previously shown drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0010] In this application, descriptions of embodiments are divided into multiple sections for convenience as needed, but unless otherwise explicitly stated, these are not independent or separate entities, but rather, regardless of the order of description, they are parts of a single example, one being a detail of another, or a modification of one or all of the other. Furthermore, as a general rule, repeated explanations of similar parts are omitted. In addition, each component in an embodiment is not essential unless otherwise explicitly stated, such as when its number is theoretically limited or when it is clearly not the case from the context.

[0011] Furthermore, in attached drawings, hatching or similar markings may be omitted even in cross-sections if it would make the drawing unnecessarily complicated or if the distinction from voids is clear. In connection with this, background contour lines may be omitted even for holes that are closed in plan view, if it is clear from the explanation, etc. Moreover, hatching or dot patterns may be added even to areas that are not voids or to indicate the boundaries of an area, even if they are not cross-sections.

[0012] The display device according to this embodiment will now be described. Figure 1 is a cross-sectional view showing an example of the display device. Figure 2 is a plan view showing an example of the display device. As shown in Figure 1, the display device 1A according to this embodiment includes a substrate 10, a wiring layer WL, an insulating film HRC, a light-emitting element 30, a lens 41, a quantum dot layer QD, a lens 42, an insulating film 50, and a driving device 70.

[0013] As shown in Figure 1, the wiring layer WL is provided on the substrate 10. The wiring layer WL comprises wiring WL1 and an interlayer insulating layer IL. The light-emitting element 30 is provided on the wiring layer WL. The light-emitting element 30 comprises a light source 31, an electrode 32, and an electrode 33. Electrodes 32 and 33 are electrically connected to the wiring WL1 of the wiring layer WL via a conductive bonding material 80. Examples of the light source 31 include light-emitting diodes and organic EL (electro-luminescence). In the example shown in Figure 1, the light source 31 is a light-emitting diode.

[0014] In this embodiment, we will explain an example using a lateral structure light-emitting diode as shown in Figure 1. However, the structure of the light-emitting diode is not limited to a lateral structure. As a modification of the example shown in Figure 1, the light-emitting diode may have a vertical structure, for example. In a vertical structure light-emitting diode, the two electrodes connected to the light-emitting diode are provided in the vertical direction of the light-emitting diode. Therefore, in a vertical structure light-emitting diode, the charge or holes in the light-emitting diode move in the vertical direction. In a lateral structure light-emitting diode, the two electrodes connected to the light-emitting diode are provided on the lower side of the light-emitting diode. Therefore, in a vertical structure light-emitting diode, the charge or holes in the light-emitting diode move in the horizontal direction.

[0015] In the example shown in Figure 1, the display device 1A has a plurality of light-emitting elements 30. The plurality of light-emitting elements 30 include light-emitting elements 30a, 30b, and 30c. Light-emitting elements 30a, 30b, and 30c are adjacent to each other. The peak emission wavelength of light-emitting element 30a is included in the ultraviolet wavelength band. The peak emission wavelength of light-emitting element 30b is included in the ultraviolet wavelength band. The peak emission wavelength of light-emitting element 30c is included in the ultraviolet wavelength band. In other words, in Figure 1, the peak emission wavelengths of light-emitting elements 30a, 30b, and 30c are all included in the ultraviolet wavelength band. In this embodiment, each of the light-emitting elements 30a, 30b, and 30c corresponds to one pixel.

[0016] As shown in Figure 1, the display device 1A has an insulating film 50 provided on the substrate 10. In the example shown in Figure 1, the insulating film 50 is provided on the wiring layer WL. The insulating film 50 has a plurality of openings. A light-emitting element 30 is provided in each of the plurality of openings in the insulating film 50. The insulating film 50 is provided so as to partition the plurality of light-emitting elements 30. The insulating film 50 can electrically isolate the plurality of light-emitting elements 30. The insulating film 50 is an insulating layer made of, for example, an organic insulating material.

[0017] As shown in Figure 1, the display device 1A has an insulating film HRC provided on the substrate 10. In the example shown in Figure 1, the insulating film HRC is provided on the wiring layer WL. The insulating film HRC is provided so as to fill the openings in the insulating film 50. Multiple light-emitting elements 30 are sealed by the insulating film HRC. Also, as shown in Figure 1, an insulating film HRC is provided on the insulating film 50 as well. The upper surface of the insulating film HRC is a flat surface. The insulating film HRC is light-transmitting. The insulating film HRC is an insulating layer made of, for example, an organic insulating material.

[0018] As shown in Figure 1, the display device 1A has a lens 41 provided on the insulating film HRC. The lens 41 is a convex lens that protrudes from the insulating film HRC. The front surface of the lens 41 is, for example, spherical. The bottom surface of the lens 41 that is in contact with the insulating film HRC is flat. The lens 41 is provided so that light emitted from the light-emitting element 30 is incident on it. In the example shown in Figure 1, the light emitted from the light-emitting element 30 passes through the insulating film HRC and is incident on the lens 41.

[0019] As shown in Figure 2, in a plan view, the lens 41 overlaps with the light-emitting element 30. Also, the peripheral edge of the lens 41 overlaps with the insulating film 50. In a plan view, the lens 41 is, for example, circular.

[0020] Lens 41 is light-transmitting. The refractive index of lens 41 is greater than that of lens 42. The refractive index of lens 41 is, for example, 1.7 to 2.1. Examples of materials for lens 41 include SiN and ZrO ２ , and Ta ２ O ５ These are some examples.

[0021] As shown in Figure 1, the quantum dot layer QD is provided on the lens 41. The quantum dot layer QD is provided so as to cover the lens 41. The quantum dot layer QD is in contact with the lens 41. The surface (back surface) of the quantum dot layer QD in contact with the lens 41 is concave. The quantum dot layer QD is also in contact with the insulating film HRC. The surface of the quantum dot layer QD in contact with the insulating film HRC is flat. The quantum dot layer QD is provided so that light that has passed through the lens 41 is incident on it. In the example shown in Figure 1, light emitted from the light-emitting element 30 passes through the insulating film HRC and the lens 41 and is incident on the quantum dot layer QD.

[0022] As shown in Figure 2, in a plan view, the quantum dot layer QD overlaps with the light-emitting element 30. In the examples shown in Figures 1 and 2, the entire lens 41 is covered by the quantum dot layer QD. Also, in a plan view, the quantum dot layer QD is circular. Furthermore, in a plan view, the lens 41 and the quantum dot layer QD are arranged concentrically.

[0023] The quantum dot layer (QD) consists of quantum dots. Quantum dots are materials composed of aggregates of particles with particle diameters ranging from several nanometers to tens of nanometers. When light is incident on a quantum dot, the quantum dot can emit light with a longer wavelength than the incident light. When light is incident on a quantum dot, the quantum dot can emit light with a wavelength corresponding to the size of the particles that make up the quantum dot. The quantum dot layer (QD) includes, for example, at least one of the following: CdSe quantum dots, InP quantum dots, ZnSe quantum dots, Si quantum dots, C quantum dots, and perovskite quantum dots. The refractive index of the quantum dot layer (QD) is, for example, 1.7 to 2.4. The particle diameter of the quantum dots is, for example, 2 nm to 10 nm.

[0024] In the example shown in Figure 1, the peak wavelength of the emission wavelength of the quantum dot layer QD is longer than the peak wavelength of the emission wavelength of the light-emitting element 30. Furthermore, the peak wavelength of the quantum dot layer QD provided on light-emitting element 30a is included in the red light wavelength band. The peak wavelength of the quantum dot layer QD provided on light-emitting element 30b is included in the green light wavelength band. The peak wavelength of the quantum dot layer QD provided on light-emitting element 30c is included in the blue light wavelength band.

[0025] Furthermore, since the quantum dot layer QD has a color conversion function, the display device 1A according to this embodiment does not have a color filter. In other words, the light emitted from each of the multiple light-emitting elements 30 is emitted to the outside of the display device 1A without passing through a color filter. A color filter is an optical film that absorbs light of a specific wavelength. Therefore, the brightness of light that passes through a color filter decreases. On the other hand, the quantum dot layer QD is an optical film that emits light of a different wavelength than the wavelength of the incident light. Therefore, by using a quantum dot layer QD instead of a color filter, the brightness of the light emitted from the display device 1A can be improved.

[0026] As shown in Figure 1, the lens 42 is provided on the quantum dot layer QD. The lens 42 is provided so as to cover the quantum dot layer QD. The lens 42 is in contact with the quantum dot layer QD. The surface (back surface) of the lens 42 in contact with the quantum dot layer QD is concave. The lens 42 is also in contact with the insulating film HRC. The surface of the lens 42 in contact with the insulating film HRC is flat. The lens 42 protrudes onto the insulating film HRC. The front surface of the lens 42 is, for example, spherical. The lens 42 is provided so as to receive light emitted from the quantum dot layer QD.

[0027] As shown in Figure 2, in a plan view, the lens 42 overlaps with the light-emitting element 30. In the examples shown in Figures 1 and 2, the entire quantum dot layer QD is covered by the lens 42. Also, in a plan view, the lens 42 is circular. Furthermore, in a plan view, the lens 41, the quantum dot layer QD, and the lens 41 are arranged concentrically.

[0028] Lens 42 is light-transmitting. The refractive index of lens 42 is smaller than that of lens 41. The refractive index of lens 42 is, for example, 1.4 to 1.5. Examples of lens 42 include alkali resin and fluorine-based polymer.

[0029] The drive unit 70 has the function of controlling the light-emitting element 30. The drive unit 70 controls the on and off of the current flowing to the light-emitting element 30 by controlling the current flowing to the light-emitting element 30, for example. The drive unit 70 is, for example, a driver IC. The drive unit 70 is electrically connected to each of the multiple light-emitting elements 30.

[0030] Next, the effects of the display device 1A according to this embodiment will be described. Figure 3 shows the display device 1F according to the example under consideration.

[0031] As shown in Figure 3, the display device 1F in the study example has a light-shielding film BM on the light-emitting element 30. The light-shielding film BM is provided on an insulating film 60 that separates a plurality of quantum dot layers QD. As a result, even if external light strikes the light-shielding film BM, the light is not reflected. Also, if external light strikes an area where the light-shielding film BM is not provided, the light is reflected. On the other hand, if light emitted by the light-emitting element 30 strikes the light-shielding film BM, it is blocked by the light-shielding film BM. If the area where the light-shielding film BM is provided is increased in order to reduce the reflection of external light, the range in which light emitted by the light-emitting element 30 can be emitted outside the display device 1A (hereinafter referred to as the aperture area) becomes smaller. As a result, the viewing angle brightness of the display device 1F becomes smaller.

[0032] On the other hand, in the display device 1A according to this embodiment, the refractive index of the inner lens 41 is greater than that of the outer lens 42. Simply arranging a low refractive index lens 42 alone would reduce the ambient light reflectance. Ambient light reflectance is defined as follows: That is, a portion of the ambient light incident on the lens 42 from the front surface of the lens 42 is reflected by the quantum dot layer QD and the lens 41, and emitted as reflected light to the outside of the lens 42. The ratio of this reflected light to the ambient light incident on the lens 42 is the ambient light reflectance. Simply arranging a low refractive index lens as a single layer does not have a significant effect on reducing ambient light reflectance, but it has been found that by combining the lens 41, the quantum dot layer QD, and the lens 42, as in this embodiment, the ambient light reflectance can be reduced. Since the display device 1A of this embodiment can reduce ambient light reflectance, it is possible to prevent the light emitted from the light-emitting element 30 from becoming difficult to see due to ambient light. For example, in the example shown in Figure 1, the display device 1A does not have a light-shielding film. However, as mentioned above, since the external light reflectivity of the lens 42 is low, the light emitted from the display device 1A is less likely to be obstructed by external light reflection.

[0033] As described above, the display device 1A according to this embodiment can prevent the light emitted from the light-emitting element 30 from becoming difficult to see due to ambient light, even without providing a light-shielding film. In the case of the display device 1A without a light-shielding film, the aperture area can be increased, and thus the viewing angle brightness can be increased. Therefore, the display device 1A according to this embodiment can achieve both increased viewing angle brightness and reduced ambient light reflectance.

[0034] Other effects of the display device 1A according to this embodiment will now be described. The display device 1A according to this embodiment has two lenses, lens 41 and lens 42, and the two lenses are arranged concentrically in a plan view. By adjusting the refractive index and aperture ratio of the two lenses, lens 41 and lens 42, the viewing angle brightness and chromaticity can be controlled. On the other hand, if there is only one lens, only the refractive index and aperture ratio of that one lens can be adjusted. Therefore, the display device 1A according to this embodiment can precisely control the viewing angle brightness and chromaticity of the display device 1A compared to the case where there is only one lens.

[0035] Furthermore, in the display device 1A according to this embodiment, the lens 41 protrudes. As a result, the portion of the quantum dot layer QD into which light is incident becomes concave. Therefore, compared to the case where the portion of the quantum dot layer QD into which light is incident is flat, the area of ​​the portion of the quantum dot layer QD into which light is incident becomes larger. In other words, according to this embodiment, the area of ​​the light incident surface of the quantum dot layer QD can be increased compared to the example shown in Figure 3. Consequently, the external quantum efficiency (EQE) of the quantum dot layer QD can be increased.

[0036] Furthermore, the display device 1A according to this embodiment can display multiple colors by using multiple light-emitting elements 30 with the same emission wavelength peak. This eliminates the need to mount multiple light-emitting elements 30 with different emission wavelengths on the substrate 10. Therefore, the display device 1A has higher manufacturing efficiency compared to a display device that mounts multiple light-emitting elements with different emission wavelengths on a substrate.

[0037] Next, a modified example of the display device according to this embodiment will be described. Figure 4 is a cross-sectional view showing an example of the display device. The display device 1B shown in Figure 4 differs from the display device 1A shown in Figure 1 in that a light-shielding film BM is provided on the insulating film 50. The light-shielding film BM overlaps with the lens 42 and the quantum dot layer QD. As shown in Figure 4, the peripheral edge of the lens 41 overlaps with the light-shielding film BM. By the peripheral edge of the lens 41 overlapping with the light-shielding film BM, the amount of light incident on the lens 42 without passing through the quantum dot layer QD can be reduced.

[0038] In the display device 1B according to this embodiment, light emitted from the light-emitting element 30 is incident on the lens 42 via the lens 41. The light incident on the lens 42 is emitted from the lens 42. Therefore, for example, by increasing the area where the light-shielding film BM is provided, even if a part of the light-shielding film BM overlaps with the lens 42 in a plan view, the light emitted from the lens 42 via the lens 41 is not blocked. As a result, the viewing angle brightness of the light emitted from the lens 42 via the lens 41 is not reduced.

[0039] As described above, the display device 1A according to this embodiment can achieve both increased viewing angle brightness and reduced ambient light reflectance, even when a light-shielding film BM is provided. Therefore, the performance of the display device 1A can be improved.

[0040] Figure 5 is a cross-sectional view showing an example of a display device. The display device 1C shown in Figure 5 differs from the display device 1A shown in Figure 1 in that the peak emission wavelength of the light-emitting element 30c is included in the blue band. Furthermore, the display device 1C shown in Figure 5 differs from the display device 1A shown in Figure 1 in that a quantum dot layer QD is not provided on the light-emitting element 30c. Also, in this modified example, since blue light is emitted from the light-emitting element 30c, there is no need to provide a color filter instead of a quantum dot layer QD. As shown in Figure 5, lenses 41 and 42 are in contact. In a plan view, the sizes of lenses 41 and 42 are not particularly limited.

[0041] In the example shown in FIG. 5, the lens provided on the light-emitting element 30 is composed of two layers, but the lens can be composed of three layers. For example, by replacing the quantum dot layer QD of the display device 1A shown in FIG. 1 with a lens having a refractive index different from that of the lenses 41 and 42, the lens can have a three-layer structure.

[0042] FIG. 6 is a cross-sectional view showing an example of a display device. The display device 1D shown in FIG. 6 is different from the display device 1C shown in FIG. 5 in that the light-emitting element 30 is an organic EL. As shown in FIG. 6, the light source 31 of the light-emitting element 30a has an organic layer 31a and an organic light-emitting layer 31b. The organic layer 31a is electrically connected to an electrode (cathode) 32 and an electrode (anode) 33. The organic light-emitting layer 31b is covered by the organic layer 31a. The insulating film 51 is provided on the insulating film 50. In the example shown in FIG. 6, the peaks of the emission wavelengths of the light-emitting elements 30a, 30b, and 30c are included in the blue band. A quantum dot layer QD is provided on the light-emitting element 30a and on the light-emitting element 30b. On the other hand, no quantum dot layer QD is provided on the light-emitting element 30c. A lens 43 is provided on the light-emitting element 30c instead of the quantum dot layer QD. That is, a three-layer lens of the lenses 41, 42, and 43 is provided on the light-emitting element 30c.

[0043] Next, a method for manufacturing the display device according to the present embodiment will be described. Hereinafter, as a representative example, the manufacturing method of the display device 1A shown in FIG. 1 will be taken up and described. FIG. 7 is a cross-sectional view showing a method for manufacturing a display device. As shown in FIG. 7, the manufacturing method of the display device according to the present embodiment includes a step of providing a light-emitting element 30 on a substrate 10. The light-emitting element 30 is electrically connected to a wiring WL1 provided on the substrate 10. Specifically, the electrodes 32 and 33 of the light-emitting element 30 are electrically connected to the wiring WL1 via a conductive bonding material 80. The manufacturing method of the display device according to the present embodiment provides a plurality of light-emitting elements 30 on the substrate 10. In the example shown in FIG. 7, the light-emitting elements 30a, 30b, and 30c are provided on the substrate 10. In the example shown in FIG. 7, the light-emitting element 30 is a light-emitting diode.

[0044] FIG. 8 is a cross-sectional view showing a method of manufacturing a display device. As shown in FIG. 8, the method of manufacturing a display device according to this embodiment includes a step of sealing the light-emitting element 30 with an insulating film HRC. The insulating film HRC has translucency. An insulating film 50 is provided between the plurality of light-emitting elements 30.

[0045] FIG. 9 is a cross-sectional view showing a method of manufacturing a display device. As shown in FIG. 9, the method of manufacturing a display device according to this embodiment includes a step of providing a lens material 41a on the insulating film HRC. After applying the lens material 41a on the insulating film HRC, the excess lens material 41a can be removed by photolithography to provide the lens material 41a on the insulating film HRC. Examples of the lens material 41a include SiN, ZrO ２ , and Ta ２ O ５ . [[ID=!1]]

[0046] FIG. 10 is a cross-sectional view showing a method of manufacturing a display device. As shown in FIG. 10, the method of manufacturing a display device according to this embodiment includes a step of forming a lens 41 by reflowing (heat treatment) the lens material 41a (see FIG. 9). When the lens material 41a is heated, the shape of the lens material 41a is deformed, and a lens 41 having a spherical front surface and a flat back surface as shown in FIG. 10 is obtained.

[0047] FIG. 11 is a cross-sectional view showing a method of manufacturing a display device. As shown in FIG. 11, the method of manufacturing a display device according to this embodiment includes a step of providing a quantum dot material QDa on the lens 41. After applying the quantum dot material QDa on the lens 41, the excess quantum dot material QDa can be removed by photolithography to provide the quantum dot material QDa on the lens 41. The quantum dot material QDa includes, for example, at least one or more of CdSe quantum dots, InP quantum dots, ZnSe quantum dots, Si quantum dots, C quantum dots, and perovskite quantum dots.

[0048] Figure 12 is a cross-sectional view showing a method for manufacturing a display device. As shown in Figure 12, the method for manufacturing a display device according to this embodiment includes a step of forming a quantum dot layer QD by reflowing a quantum dot material QDa (see Figure 11). When the quantum dot material QDa is heated, the shape of the quantum dot material QDa deforms to conform to the shape of the lens 41. As a result, a quantum dot layer QD is obtained in which the front surface is a convex sphere and the back surface is concave, as shown in Figure 12.

[0049] Figure 13 is a cross-sectional view showing a method for manufacturing a display device. As shown in Figure 13, the method for manufacturing a display device according to this embodiment includes the step of providing a lens material 42a on a quantum dot layer QD. After coating the lens material 42a onto the quantum dot layer QD, the excess lens material 42a can be removed by photolithography to provide the lens material 42a on the quantum dot layer QD. Examples of lens material 42a include alkali resins and fluoropolymers.

[0050] Figure 14 is a cross-sectional view showing a method for manufacturing a display device. As shown in Figure 14, the method for manufacturing a display device according to this embodiment includes a step of forming a lens 42 by reflowing a lens material 42a. When the lens material 42a is heated, the shape of the quantum dot material QDa deforms to conform to the shape of the lens 41. As a result, a lens 42 is obtained in which the front surface is a convex sphere and the back surface is concave, as shown in Figure 13.

[0051] In this embodiment, the displayed color is determined by the quantum dot layer QD provided on the plurality of light-emitting elements 30. Therefore, even if the emission wavelength peaks of the plurality of light-emitting elements 30 are all the same, multiple colors can be displayed. Since the emission wavelength peaks of the plurality of light-emitting elements 30 can all be the same, it is not necessary to mount a plurality of light-emitting elements 30 with different emission wavelengths on the substrate 10. When using the stamp transfer method, for example, if three types of light-emitting elements are used, at least three transfers are required. On the other hand, if one type of light-emitting element is used, the number of transfers can be reduced to, for example, one, thus reducing manufacturing costs. Therefore, the manufacturing cost of the display device manufacturing method according to this embodiment is lower compared to the manufacturing method of a display device in which a plurality of light-emitting elements with different emission wavelengths are mounted on a substrate.

[0052] Within the scope of the spirit of the present invention, a person skilled in the art can conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the scope of the present invention. For example, any addition, deletion, or design change of components, or addition, omission, or modification of processes, made by a person skilled in the art to the above-described embodiments, is also included within the scope of the present invention, as long as it retains the gist of the present invention.

[0053] Furthermore, any other effects and advantages brought about by the manner described in this embodiment that are evident from this specification or that can be appropriately conceived by a person skilled in the art are naturally considered to be brought about by the present invention.

[0054] 1A, 1B, 1C, 1D, 1F Display device 10 Substrate 30, 30a, 30b, 30c Light-emitting element 31 Light source 31a Organic layer 31b Organic light-emitting layer 32, 33 Electrode 41 Lens 41a Lens material 42 Lens 42a Lens material 43 Lens 50, 51 Insulating film 70 Driving device 80 Conductive bonding material WL Wiring layer WL1 Wiring IL Interlayer insulating layer QD Quantum dot layer QDa Quantum dot material HRC Insulating film

Claims

1. A display device comprising: a substrate; a light-emitting element provided on the substrate; a first lens provided to receive light emitted from the light-emitting element and having a first refractive index; a quantum dot layer provided to cover the first lens; and a second lens provided to cover the quantum dot layer and having a second refractive index smaller than the first refractive index, wherein the first lens is provided between the quantum dot layer and the light-emitting element.

2. A display device according to claim 1, wherein, in a plan view, the first lens, the quantum dot layer, and the second lens are arranged concentrically.

3. A display device according to claim 1, wherein the peak emission wavelength of the light-emitting element is a first wavelength, and the peak emission wavelength of the quantum dot layer is a second wavelength that is longer than the first wavelength.

4. A display device according to claim 3, wherein the first wavelength is included in the ultraviolet wavelength band, and the second wavelength is included in the blue light wavelength band.

5. A display device according to claim 3, wherein the first wavelength is included in the ultraviolet wavelength band, and the second wavelength is included in the green light wavelength band.

6. A display device according to claim 3, wherein the first wavelength is included in the ultraviolet wavelength band, and the second wavelength is included in the red light wavelength band.

7. A display device according to claim 3, further comprising a plurality of the light-emitting elements, wherein the first wavelength, which is the peak of the emission wavelengths of the plurality of light-emitting elements, is included in the ultraviolet wavelength band.

8. A display device according to claim 3, further comprising a plurality of the light-emitting elements, wherein the plurality of light-emitting elements include light-emitting elements whose emission wavelength peak is included in the blue light wavelength band, and the quantum dot layer is not provided on the light-emitting elements whose emission wavelength peak is included in the blue light wavelength band.

9. A display device according to claim 1, wherein the light-emitting element is a light-emitting diode.

10. A display device according to claim 1, wherein the light-emitting element is an organic EL.

11. A display device according to claim 1, wherein the quantum dot layer comprises at least one of the following: CdSe quantum dots, InP quantum dots, ZnSe quantum dots, Si quantum dots, C quantum dots, and perovskite quantum dots.

12. A display device according to claim 1, further comprising: an insulating film that seals the light-emitting element; and a light-shielding film provided on the insulating film, wherein the peripheral edge of the first lens overlaps with the light-shielding film.

13. A display device according to claim 1, further comprising an insulating film for sealing the light-emitting element, wherein the first lens is a convex lens protruding from the insulating film.

14. A display device according to claim 1, wherein the refractive index of the first lens is 1.7 to 2.1, and the refractive index of the second lens is 1.4 to 1.

5.

15. A method for manufacturing a display device, comprising: (a) providing a light-emitting element on a substrate; (b) sealing the light-emitting element with an insulating film; (c) providing a first lens having a first refractive index on the insulating film; (d) providing a quantum dot layer so as to cover the first lens; and (e) providing a second lens having a second refractive index smaller than the first refractive index so as to cover the quantum dot layer.

16. A method for manufacturing a display device according to claim 15, wherein in step (a), a light-emitting element whose emission wavelength peak is included in the ultraviolet wavelength band is arranged in each of a plurality of adjacent pixels.

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