Micro light emitting element and image display element

Abstract

To improve a conversion efficiency of a wavelength conversion part, and reduce a power consumption.SOLUTION: A micro light-emitting element (100) is the micro light-emitting element (100) formed by: an excitation light emitting element (105) that emits an excitation light; and a red wavelength conversion part (32) that contains a nano particle absorbing the excitation light, and discharging a light of which a wavelength is longer than that of the excitation light. The micro light-emitting element includes at least one or more layers containing a dielectric multi-layer film (74) on a surface of a light discharge side of the red wavelength conversion part (32).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to micro light emitting devices and image display devices including the micro light emitting devices. [Background technology]

[0002] Conventionally, display elements have been proposed in which a plurality of micro light-emitting elements constituting pixels are arranged on a driving circuit substrate. For example, in the technology disclosed in Patent Document 1, a driving circuit is formed on a silicon substrate, and a micro light-emitting diode (micro LED) array that emits ultraviolet light is arranged on the driving circuit. The technology also discloses a small display element that displays color images by providing a wavelength conversion portion on the light-emitting diode array that converts ultraviolet light into red, green, and blue visible light.

[0003] The method of combining a micro LED and a wavelength conversion unit as a micro light-emitting element, as in Patent Document 1, makes it easy to realize a full-color display element. Furthermore, by using nitride semiconductors as the material for the micro LED, it is possible to realize a display element with little efficiency loss due to temperature rise and high durability. For this reason, it is expected to be used as a display element for display devices such as glasses-like devices and head-up displays (HUDs).

[0004] Nanomaterials such as quantum dots (QD) and quantum rods (QR) have attracted attention as materials for the wavelength conversion section, due to their high conversion efficiency and narrow full width at half maximum (FWHM) of the emission spectrum, which allows for a wide display color gamut and high color rendering.

[0005] To ensure stable use of nanomaterials such as quantum dots, it is necessary to prevent moisture and oxygen from entering. For application to backlights of liquid crystal displays, a structure in which a barrier film and a getter layer are laminated has been proposed, as in Patent Document 2. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2002-141492 (published May 17, 2002) [Patent Document 2] Japanese Patent Publication No. 2016-103461 (published June 2, 2016) Summary of the Invention [Problem to be solved by the invention]

[0007] As a result of the inventor's investigation, it was found that the nanomaterials used in the wavelength conversion section of the microdisplays for eyeglass-type terminals deteriorate easily. In other words, even before the deterioration over time becomes an issue, it was found that the wavelength conversion efficiency at the stage when manufacturing is completed is much lower than the wavelength conversion efficiency expected from the inherent properties of the nanomaterials.

[0008] One of the reasons for this is thought to be the thin thickness of the wavelength conversion section. Microdisplays for eyeglass-type devices require a pixel size of 10 μm or less, and the size of the subpixels that emit red, green, blue, and other light components of each pixel must be 5 μm or less. The thickness of the wavelength conversion section required to realize such a microdisplay is 5 μm or less. This is approximately 1 / 10 the thickness of the quantum dot-containing film used in the backlight module of a liquid crystal display device, which is the subject of Patent Document 2. When the thickness of the wavelength conversion section is as thick as that of a quantum dot-containing film for a backlight, even if some degradation occurs on the surface, as long as there is no internal degradation, the characteristics will not deteriorate significantly. For example, if the quantum dot-containing film for a backlight is 50 μm thick, even if the conversion efficiency of the surface 5 μm is 0%, the overall conversion efficiency will be 90% or more compared to a case without degradation.

[0009] Furthermore, in microdisplays, each subpixel emits a different light color, so a wavelength conversion section containing a different nanomaterial must be formed for each subpixel. For example, if a red-emitting quantum dot layer is formed in the red subpixel and then a green-emitting quantum dot layer is formed in the green subpixel, the red-emitting quantum dot layer will be affected by the process of forming the green-emitting quantum dot layer. Thus, the lengthy process of forming the wavelength conversion section is also thought to be a cause of the deterioration.

[0010] Regarding the wavelength conversion unit of the microdisplay for eyeglass-type terminals, it is necessary to reduce the deterioration of the quantum dot layer during the manufacturing process of the wavelength conversion unit, but if the deterioration cannot be avoided, a technology to recover from the deterioration is required.

[0011] One aspect of the present invention was made in consideration of these problems, and its purpose is to reduce the power consumption of micro-light-emitting elements and image display elements having wavelength conversion sections by recovering the deterioration of nanomaterials during the manufacturing process and increasing the wavelength conversion efficiency in the micro-light-emitting elements and image display elements that include such micro-light-emitting elements. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, a micro light-emitting device according to one aspect of the present invention is a micro light-emitting device comprising a micro LED element that emits excitation light, and a wavelength conversion section that contains nanoparticles that absorb the excitation light and emit light having a longer wavelength than the excitation light, wherein at least a laminate including one or more layers including a first oxygen absorption film is provided on the light-emitting side surface of the wavelength conversion section, and a second oxygen absorption film is further provided on the surface of the wavelength conversion section that faces the micro LED element, and the first oxygen absorption film and the second oxygen absorption film are made of inorganic oxides. The second oxygen absorbing film functions as a transparent electrode of the micro LED element. It is characterized by:

[0013] In order to solve the above-mentioned problems, a micro light-emitting element according to one aspect of the present invention is a micro light-emitting element comprising a micro LED element that emits excitation light, and a wavelength conversion unit that includes nanoparticles that absorb the excitation light and emit light having a longer wavelength than the excitation light, and at least on the light-emitting surface of the wavelength conversion unit: Forming the first oxygen absorbing film It has one or more laminated layers including an inorganic oxide thin film. a second oxygen absorbing film made of an inorganic oxide on the surface of the wavelength conversion section facing the micro LED element; The inorganic oxide thin film is characterized in that the nanoparticles increase the conversion efficiency over time of converting the excitation light into light having a longer wavelength than the excitation light.

[0014] Furthermore, an image display element according to one aspect of the present invention is an image display element including: micro light-emitting elements arranged in an array; and a drive circuit board including a drive circuit that supplies current to the micro light-emitting elements to cause them to emit light, wherein the micro light-emitting elements include excitation light-emitting elements that emit excitation light and light that absorbs the excitation light and emits light having a longer wavelength than the excitation light. Contains nanoparticlesand a wavelength conversion unit, the excitation light emitting element and the wavelength conversion unit being stacked in this order on the drive circuit board, the micro light emitting element emitting light having a longer wavelength than the excitation light upward in the opposite direction to the drive circuit board, partition walls being arranged on the side surfaces of the wavelength conversion unit, a first oxygen absorption film being arranged at least on the surface of the wavelength conversion unit in the light emission direction, and a second oxygen absorption film being further arranged on the surface of the wavelength conversion unit facing the excitation light emitting element, the first oxygen absorption film and the second oxygen absorption film being made of inorganic oxide. The first oxygen absorbing film increases over time the conversion efficiency of the nanoparticles in converting the excitation light into light having a longer wavelength than the excitation light. . An image display element according to one embodiment of the present invention is an image display element comprising: micro light-emitting elements arranged in an array; and a drive circuit board including a drive circuit that supplies current to the micro light-emitting elements to cause them to emit light; the micro light-emitting elements comprise excitation light-emitting elements that emit excitation light; and a wavelength conversion unit that absorbs the excitation light and emits light having a longer wavelength than the excitation light; the excitation light-emitting elements and the wavelength conversion unit are stacked in this order on the drive circuit board; the micro light-emitting elements emit light having a longer wavelength than the excitation light upward, in the opposite direction from the drive circuit board; a partition is arranged on the side of the wavelength conversion unit; and a first oxygen absorption film is arranged at least on the surface of the wavelength conversion unit in the light emission direction; the first oxygen absorption film is divided into each wavelength conversion unit; and the ends of the first oxygen absorption film divided into each wavelength conversion unit are on the upper surface of the partition. An image display element according to one embodiment of the present invention is an image display element comprising: micro light-emitting elements arranged in an array; and a drive circuit board including a drive circuit that supplies current to the micro light-emitting elements to cause them to emit light; the micro light-emitting elements comprise excitation light-emitting elements that emit excitation light; and a wavelength conversion unit that absorbs the excitation light and emits light having a longer wavelength than the excitation light; the excitation light-emitting elements and the wavelength conversion unit are stacked in this order on the drive circuit board; the micro light-emitting elements emit light having a longer wavelength than the excitation light upward, in the opposite direction from the drive circuit board; a partition is arranged on the side of the wavelength conversion unit; a first oxygen absorption film is arranged on at least the surface of the wavelength conversion unit facing the light emission direction; and a second oxygen absorption film is further formed on the surface of the wavelength conversion unit facing the excitation light-emitting elements; the first oxygen absorption film and the second oxygen absorption film are made of an inorganic oxide; and the second oxygen absorption film functions as a transparent electrode of the excitation light-emitting element. [Effects of the Invention]

[0015] According to one aspect of the present invention, the conversion efficiency of the wavelength conversion unit is improved, thereby reducing the power consumption of the micro light-emitting element and the image display element. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view schematically illustrating an image display element according to a first embodiment of the present invention. [Figure 2] 1 is a plan view schematically illustrating a wavelength conversion section of an image display element according to a first embodiment of the present invention, viewed from above. [Figure 3] 1 is a plan view schematically illustrating an excitation light-emitting element of an image display element according to a first embodiment of the present invention, viewed from above. [Figure 4] 1 is an enlarged cross-sectional view of the vicinity of the upper surface of a wavelength conversion section of an image display element according to a first embodiment of the present invention. [Figure 5] 10 is an enlarged cross-sectional view of the vicinity of the upper surface of the wavelength conversion section, showing another example of the oxygen absorbing film of the image display element according to the first embodiment of the present invention. FIG. [Figure 6] FIG. 10 is an enlarged cross-sectional view of the vicinity of the upper surface of the wavelength conversion section, showing yet another example of the oxygen absorbing film of the image display element according to the first embodiment of the present invention. [Figure 7] FIG. 10 is an enlarged cross-sectional view of the vicinity of the upper surface of the wavelength conversion section, showing yet another example of the oxygen absorbing film of the image display element according to the first embodiment of the present invention. [Figure 8] 1 is a cross-sectional STEM photograph of the vicinity of the upper surface of a wavelength conversion section of the image display element according to the first embodiment of the present invention. [Figure 9] 4 is a graph showing the change over time in red sunlight intensity under blue light irradiation for the image display element according to the first embodiment of the present invention. [Figure 10] FIG. 4 is a cross-sectional view schematically illustrating an image display element according to a second embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional view schematically illustrating an image display element according to a third embodiment of the present invention. [Figure 12] FIG. 10 is a cross-sectional view schematically illustrating an image display element according to a fourth embodiment of the present invention. [Figure 13] FIG. 10 is a cross-sectional view schematically illustrating an image display element according to a fifth embodiment of the present invention. [Figure 14] 10 is a plan view schematically illustrating a wavelength conversion section of an image display element according to a fifth embodiment of the present invention, viewed from above. FIG. [Figure 15] FIG. 10 is a cross-sectional view illustrating an image display element according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 15, taking an image display element having a plurality of micro light-emitting elements as an example. The image display element includes a plurality of micro light-emitting elements and a drive circuit board, and the drive circuit board supplies current to the micro light-emitting elements in a pixel region to control light emission. The micro light-emitting elements are arranged in an array in the pixel region. The micro light-emitting elements emit light on the side opposite to the drive circuit board. Unless otherwise specified, the surface of the micro light-emitting element that emits light into the air is referred to as the light-emitting surface. In describing the configuration of the image display element, unless otherwise specified, the light emitting surface is referred to as the top surface (first surface), the surface opposite the light emitting surface is referred to as the bottom surface (second surface), and the lateral surfaces other than the top and bottom surfaces are referred to as the side surfaces. The direction perpendicular to the light emitting surface, facing into the air, is referred to as the front. The surface of the drive circuit board is the bonding surface that bonds with the multiple micro light emitting elements, and the multiple micro light emitting elements are bonded to it. Unless otherwise specified, the horizontal surface refers to a surface parallel to the bonding surface.

[0018] The drive circuit board has a micro light emitting element driving circuit in the pixel area that controls the current supplied to each micro light emitting element, and a row selection circuit that selects each row of the micro light emitting elements arranged in a two-dimensional matrix, a column signal output circuit that outputs light emitting signals to each column, an image processing circuit that calculates the light emitting signal based on an input signal, and an input / output circuit arranged outside the pixel area. An N-drive electrode (first drive electrode) and a P-drive electrode (second drive electrode) that connect to the micro light emitting elements are arranged on the surface of the bonding side of the drive circuit board. The drive circuit board is generally a silicon substrate (semiconductor substrate) on which an LSI (integrated circuit) is formed, or a glass or plastic substrate on which a TFT (thin film transistor) is formed. Since it can be manufactured using known techniques, its function and configuration will not be described in detail.

[0019] In this specification, only the structure in which the P electrode and the P drive electrode are directly connected to each other is shown, but a member for connection such as a bump, paste, or nanoparticles may be interposed between the two.

[0020] In the following, excitation light-emitting elements will be described primarily as being made of nitride semiconductors. However, the material of the light-emitting layer is not limited to nitride semiconductors and may be other compound semiconductor materials, such as perovskite materials and quantum dot materials. Regarding the nitride semiconductor layer, a configuration in which the P-side layer is disposed on the drive circuit board side will be described. However, a configuration in which the P-side layer is disposed on the light-emitting surface side is also possible. The N-side layer, light-emitting layer, and P-side layer are each typically optimized to include multiple layers rather than a single layer. However, since this is not directly related to one aspect of the present invention, the detailed structures of the N-side layer, light-emitting layer, and P-side layer will not be described in detail. Typically, the light-emitting layer is sandwiched between an N-type layer and a P-type layer. However, the N-type layer and P-type layer may also include undoped layers or layers containing dopants with opposite conductivity. For this reason, the N-type layer and P-type layer will be referred to as the N-side layer and the P-side layer, respectively.

[0021] In the figure, the micro-light-emitting element is depicted as being approximately square, but the shape of the micro-light-emitting element is not particularly limited. The micro-light-emitting element can have various planar shapes, such as triangle, rectangle, polygon, circle, or ellipse, but the longest length is assumed to be 60 μm or less. The image display element is assumed to have more than 3,000 micro-light-emitting elements integrated in the pixel area 1.

[0022] [Embodiment 1] (Configuration of image display element 200) Fig. 1 is a cross-sectional view of a pixel region 1 of an image display element 200 according to Embodiment 1 of the present invention. Fig. 2 is a plan view of a red wavelength conversion unit 32 in the pixel region 1 of the image display element 200 according to Embodiment 1 of the present invention, viewed from above. Fig. 3 is a plan view of an excitation light-emitting element 105 in the pixel region 1 of the image display element 200 according to Embodiment 1 of the present invention, viewed from above. Fig. 1 shows a cross-sectional view of the AA line portion in Figs. 2 and 3.

[0023] 2, when the pixel region 1 of the image display element 200 is viewed from above, a plurality of pixels 5 are arranged in an array. In this embodiment, the image display element 200 is a monochrome display element, and each pixel 5 includes one monochrome micro light emitting element 100. In the image display element 200, each pixel 5 emits red light, and by adjusting the intensity of each pixel, a monochrome red image is displayed.

[0024] The micro light-emitting element 100 includes an excitation light-emitting element 105 (micro LED element (light emitting diode)) that emits blue light, a red wavelength conversion section 32, and a partition wall 34. The excitation light-emitting element 105 includes a nitride semiconductor layer 14, an N-electrode 24N (first electrode), and a P-electrode 23P (second electrode). The nitride semiconductor layer 14 includes an N-side layer 11, a light emission layer 12, and a P-side layer 13 stacked from the light-emitting surface side. A mesa 16 separates the P-side layer 13 and a portion of the N-side layer 11 from the other light-emitting elements. The periphery of the mesa 16 is covered with a protective film 17. A continuous N-side layer 11C, which is a layer on the upper surface of the N-side layer 11, is continuous between adjacent pixels and forms part of the N-electrode wiring. An N-electrode 24N is disposed on the lower surface of the continuous N-side layer 11C remaining between the mesas 16. The N electrodes 24N may be arranged in a mesh pattern as shown in FIG.

[0025] A P-electrode 23P is connected to the P-side layer 13, and is connected to a P-drive electrode 52 on the drive circuit substrate 50. The N-electrode 24N is connected to an N-drive electrode (not shown) outside the pixel region 1. The amount of light emitted by the excitation light-emitting element 105 is controlled according to the amount of current flowing between the N-drive electrode and the P-drive electrode 52 of the drive circuit substrate 50. The excitation light-emitting element 105 and a red wavelength conversion section 32 are stacked in this order on the drive circuit substrate 50.

[0026] The space between the excitation light emitting element 105 and the drive circuit board 50 is preferably filled with a filling material 60. The filling material 60 may be an underfill material made of resin, or may be an inorganic film such as SiO2. The filling material 60 may be transparent, but preferably has light blocking properties.

[0027] As shown in FIG. 1, a red wavelength conversion section 32 and a partition wall 34 are disposed above the excitation light-emitting element 105. The partition wall 34 is disposed on the boundary between adjacent pixels 5 and on the side surface of the red wavelength conversion section 32. In this configuration, the partition wall 34 is made of a metal film having inclined side surfaces. The side walls of the partition wall 34 preferably have high reflectivity, and the partition wall 34 preferably contains aluminum or silver as its main component. The side surfaces of the partition wall 34 are inclined so as to open toward the light emission direction. The angle between the side wall and the horizontal plane is defined as the inclination angle θw. The smaller the inclination angle θw, the better.

[0028] The red wavelength conversion section 32 is made of a resin material containing nanoparticles (quantum dots) that absorb the excitation light emitted from the excitation light-emitting element 105 and emit long-wavelength light with a longer wavelength than the excitation light upward, in the direction opposite to the drive circuit board 50. Hereinafter, nanoparticles contained in the wavelength conversion section that absorb the excitation light and emit long-wavelength light with a longer wavelength than the excitation light are referred to as wavelength conversion nanoparticles. The red wavelength conversion section 32 may also contain scattering particles that do not absorb the excitation light and do not perform wavelength conversion. The height of the red wavelength conversion section 32 is preferably the same as the height of the partition walls 34, but as shown in FIG. 1, the red wavelength conversion section 32 may be higher. By making the red wavelength conversion section 32 higher than the partition walls 34, the surface becomes flat, making it easier to form a thin film on the red wavelength conversion section 32. If there are steps on the top surfaces of the red wavelength conversion section 32 and the partition walls 34, a transparent resin layer may be formed on the top surfaces of the red wavelength conversion section 32 and the partition walls 34 to flatten the surfaces.

[0029] 1, after bonding the excitation light emitting element 105 to the drive circuit board 50, the partition walls 34 are formed, the red wavelength conversion section 32 is formed, and then the dielectric multilayer film 74 is formed. The unevenness of the partition walls 34 may reduce the film thickness uniformity of the red wavelength conversion section 32, which may cause cracks in the dielectric multilayer film 74. To avoid such problems, it is desirable that the partition walls 34 extend outside the pixel region 1 and that slopes are formed at the ends. A smooth slope can be formed, for example, by forming a thermo-fluidic resin pattern at the end and heating it.

[0030] On the red wavelength conversion section 32 (the light emitting surface of the red wavelength conversion section 32), one or more laminated layers (one or more laminated layers including an inorganic oxide thin film) including an oxygen absorbing film are formed. In this embodiment, a dielectric multilayer film 74 (oxygen absorbing film, inorganic oxide thin film) is formed on the red wavelength conversion section 32. The dielectric multilayer film 74 continuously covers the entire surface of the red wavelength conversion section 32 in the light emitting direction. The dielectric multilayer film 74 has the property of reflecting blue light (excitation light) emitted by the excitation light emitting element 105 and transmitting red light (long wavelength light), thereby reducing the emission of blue light and increasing the amount of red light emitted.

[0031] The dielectric multilayer film 74 is made of titanium oxide (TiO x ) film and silicon oxide (SiO y ) films are laminated in 10 and 11 layers, respectively, with a total film thickness of 1.3 μm. Here, x and y are numbers greater than 0 and less than 2. x Instead of niobium oxide (NbO m ) and tantalum oxide (TaO n ) may be used as the constituent material of the dielectric multilayer film 74, and TiO x Membrane and SiO y The combination is not limited to the above, where m and n are numbers greater than 0 and less than 3. In this configuration, the dielectric multilayer film 74 is formed by sputtering, but may also be formed by evaporation.

[0032] [Table 1]

[0033] Using the above structure, samples A, B, and C were prepared as shown in Table 1. The luminance of red light (long wavelength light) was compared immediately after the formation of the dielectric multilayer film 74 and after three months of storage. A significant increase was observed. It was found that storage improved the conversion efficiency of the red wavelength conversion section 32. Note that samples A, B, and C used different quantum dot materials as wavelength conversion nanoparticles, and this phenomenon is not believed to be specific to a particular quantum dot material. In structures without the dielectric multilayer film 74, i.e., structures in which the red wavelength conversion section 32 is directly exposed to air, or structures in which a transparent resin layer is formed on the red wavelength conversion section 32, this increase was not observed and tended to decrease. The improvement in the conversion efficiency of the red wavelength conversion section 32 led us to believe that the dielectric multilayer film 74 does not simply function as a barrier film to prevent the intrusion of oxygen and moisture from the outside.

[0034] Therefore, a similar experiment was conducted by forming the dielectric multilayer film 74 while varying the amount of oxygen added to the reaction gas. The results showed that the smaller the amount of oxygen added, the greater the improvement in conversion efficiency after storage. From these results, it is inferred that the constituent layers of the dielectric multilayer film 74 change from a stoichiometric composition to an oxygen-deficient state, absorbing the oxygen contained in the red wavelength conversion section 32 and suppressing non-radiative recombination of the quantum dots (wavelength conversion nanoparticles), thereby improving conversion efficiency.

[0035] It is known that the quantum dot material (wavelength conversion nanoparticle material) contained in the red wavelength conversion section 32 decreases in conversion efficiency when exposed to air, and oxygen is thought to be the cause. However, since the conversion efficiency of the quantum dots (wavelength conversion nanoparticles) recovers, it is assumed that an irreversible chemical change, such as oxidation by oxygen, is not occurring. During the manufacturing process of the red wavelength conversion section 32, exposure to oxygen reduces the conversion efficiency, but removing the oxygen is believed to restore the conversion efficiency. The quantum dot material (wavelength conversion nanoparticle material) used in this study is a material with a core made of indium phosphide (InP) surrounded by a shell primarily made of zinc sulfide (ZnS). The core diameter is generally approximately 1 nm to 10 nm and is selected appropriately depending on the emission wavelength. Other core-shell quantum dots can also be used as wavelength conversion nanoparticles. For example, the core material is CdS. x Se 1-x The shell material may be ZnSe (zinc selenide), etc. Furthermore, wavelength conversion nanoparticles are not limited to core-shell quantum dots, and other materials may be used as luminescent nanomaterials. For example, perovskite nanocrystals (CsPbX3, where X = Cl, Br, or I) may also be used.

[0036] If the above reasoning is correct, similar effects should be achievable with oxide layers other than the dielectric multilayer film 74. Therefore, instead of the enlarged view of the red wavelength conversion section 32 shown in Figure 4 (Figure 1), we fabricated a structure in which an AZO (aluminum-doped zinc oxide) film 75 was placed on the red wavelength conversion section 32, as shown in Figure 5, and conducted the same experiment. The AZO film was formed by sputtering, similar to the dielectric multilayer film 74, but the amount of oxygen added to the argon (Ar) gas used for sputtering was reduced by one-third compared to the usual amount. The AZO film 75 used in this experiment had a thickness of 220 nm. X-ray diffraction analysis revealed no clear diffraction peaks, suggesting that it was in an amorphous state. Comparing the red-band luminance of the AZO film 75 immediately after its formation and three months later, a 29% increase was observed. Despite being thinner than the dielectric multilayer film 74, it achieved effects equal to or greater than those of the dielectric multilayer film 74.

[0037] Furthermore, we compared the case where an AZO film 75 and a dielectric multilayer film 74 are stacked in this order on the red wavelength converting section 32, as shown in FIG. 6, with the case where an AZO film 75 and a dielectric multilayer film 74 are stacked on the red wavelength converting section 32 in the reverse order, as shown in FIG. 7. In other words, FIG. 6 shows the case where an AZO film 75 is located in contact with the red wavelength converting section 32 (on the red wavelength converting section 32 side), and a dielectric multilayer film 74 is located thereon. FIG. 7 shows the case where a dielectric multilayer film 74 is located in contact with the red wavelength converting section 32 (on the red wavelength converting section 32 side), and an AZO film 75 is located thereon. The improvement in conversion efficiency was 47% and 56%. The improvement was greater when the AZO film 75 and the dielectric multilayer film 74 were stacked, which is thought to be due to the additive oxygen absorption capabilities of both films.

[0038] Figure 8 is a STEM (scanning transmission electron microscope) image of the AZO film 75 and the dielectric multilayer film 74 of the structure in Figure 6. The AZO film 75 is an amorphous film, and does not exhibit the columnar or granular structures commonly seen in polycrystalline films. The dielectric multilayer film 74 also does not exhibit grain boundaries, and is thought to have an amorphous structure. It is known that an amorphous state generally has many dangling bonds, and oxygen vacancies are thought to occur easily in oxides. Note that the entire oxide film does not need to be amorphous; a mixture of fine crystal grains and amorphous phases is also acceptable.

[0039] The above-described improvement in wavelength conversion properties occurs not only with wavelength-converting nanoparticles that convert red light but also with wavelength-converting nanoparticles that convert green light. However, since this is similar to the case of red light, it will not be repeated. The sample was stored in a dark place, but an improvement in conversion efficiency was observed even under light irradiation. Figure 9 shows the change in red light intensity over time under blue light irradiation for the red wavelength conversion section 32 shown in Figure 8, which has an AZO film 75 and a dielectric multilayer film 74. After 200 hours, the intensity increased by 20% compared to immediately after the formation of the AZO film 75 and the dielectric multilayer film 74 (time 0 h). Therefore, this phenomenon is believed to be useful for practical use as a display element. After 200 hours, gradual deterioration due to light irradiation occurred, but this phenomenon also occurs in structures without the AZO film 75 and the dielectric multilayer film 74.

[0040] As described above, by arranging a thin film made of an oxygen absorbing film in the light emission direction of the wavelength conversion section, the light conversion efficiency of the wavelength conversion nanoparticles in the wavelength conversion section can be improved (increased) over time. Furthermore, by improving the conversion efficiency of the wavelength conversion section, the power consumption of the micro light emitting element 100 or the image display element 200 can be reduced. This makes it easy to realize a color display element with high efficiency and low power consumption. Furthermore, by increasing the wavelength conversion efficiency, the light emitting efficiency can be increased, resulting in a wide color gamut and high color rendering properties.

[0041] The oxygen absorption film is not limited to the above-mentioned specific inorganic oxides, but may be composed of an inorganic oxide whose composition is shifted in the direction of oxygen deficiency from the stoichiometric composition (stoichiometric state). The oxygen absorption film may also be an inorganic oxide film including an amorphous state. By disposing the oxygen absorption film continuously over the entire surface in the light emission direction of the wavelength conversion section, the conversion efficiency of the wavelength conversion section can be improved, and a highly efficient micro-light-emitting element or image display element can be provided.

[0042] [Embodiment 2] Another embodiment of the present invention will be described below with reference to FIG. 10. For ease of explanation, components having the same functions as those described in the previous embodiment will be denoted by the same reference numerals, and their description will not be repeated. The image display element 200a of embodiment 2 differs from embodiment 1 in the configuration of the oxygen absorbing film. Other points are the same as embodiment 1. The following describes the differences from embodiment 1.

[0043] In this configuration, a second AZO film 77 (second oxygen absorbing film, third oxygen absorbing film, second inorganic oxide thin film, third inorganic oxide thin film) is provided on the surface of the continuous N-side layer 11C and the surface of the partition wall 34. That is, by disposing an AZO film, which is an oxygen absorbing film, on the underside and side surfaces of the red wavelength converting section 32 as well, the entire periphery of the red wavelength converting section 32 is covered with the oxygen absorbing film. It is believed that the greater the surface area on which the oxygen absorbing film is disposed, the greater the effect of improving the conversion efficiency. This further enhances the recovery of the conversion efficiency of the red wavelength converting section 32. With this structure, the second AZO film 77 can be deposited before the formation of the red wavelength converting section 32, which adds a process step but does not result in a significant increase in costs.

[0044] Furthermore, in this configuration, the dielectric multilayer film 74a, which is an oxygen absorbing film, is divided for each pixel 5 (each red wavelength conversion section 32). The edges of the divided dielectric multilayer film 74a are located on the upper surface of the partition wall 34. Dividing the dielectric multilayer film for each pixel 5 increases the number of processes and is cost-effective, but this may be necessary to prevent optical crosstalk that occurs through the dielectric multilayer film 74a. However, as the pixel 5 becomes smaller, it may become difficult to reliably position the edges of the dielectric multilayer film 74a on the upper surface of the partition wall 34. Due to variations in manufacturing precision, the edges of the dielectric multilayer film 74a may deviate from the upper surface of the partition wall 34, resulting in a situation where part of the upper surface of the red wavelength conversion section 32 is not covered by the dielectric multilayer film 74a. Even in such cases, in this configuration, the second AZO film 77 is located on the lower and side surfaces of the red wavelength conversion section 32, thereby enabling recovery of conversion efficiency.

[0045] This embodiment can also be applied to cases where the oxygen absorbing film is configured other than the dielectric multilayer film 74a. The AZO film in the first embodiment, a combination of an AZO film and a dielectric multilayer film, or another oxygen absorbing film may be used. Alternatively, only the main layer that generates optical crosstalk may be divided between the pixels 5, such that the thin AZO film is not divided between the pixels 5, and only the thick dielectric multilayer film 74a is divided between the pixels 5. The second AZO film 77 can also be replaced with another oxygen absorbing film.

[0046] In this configuration, the same effects as in the first embodiment can be achieved.

[0047] [Embodiment 3] Another embodiment of the present invention will be described below with reference to FIG. 11. For ease of explanation, components having the same functions as those described in the previous embodiment will be denoted by the same reference numerals, and their description will not be repeated. The image display element 200b of embodiment 3 differs from embodiment 1 in the configuration of the oxygen absorbing film. Other points are the same as embodiment 1. The following describes the differences from embodiment 1.

[0048] In this configuration, a nanoparticle film 76 is used as the oxygen absorption film. A nanoparticle film is a thin film composed of an aggregate of particles with an average diameter of several nanometers (nm) to several hundred nanometers. Suitable materials for the nanoparticles of the nanoparticle film 76 are inorganic materials with transparent and stable properties, such as single-element oxides such as SiO2, TiO2, Nb2O3, and Al2O3, multi-element oxides containing multiple elements, nitrides such as Si3N4, oxynitrides such as SiON, and nitride carbides such as SiCN. The nanoparticle film 76 can be formed on a thin film by dispersing nanoparticles in a solvent or resin and applying it to the red wavelength conversion section 32. The nanoparticles may be bonded together with a transparent resin.

[0049] In FIG. 11 , the surface height of the red wavelength conversion section 32 is lower than the height of the partition wall 34. The step between the red wavelength conversion section 32 and the partition wall 34 is filled with a nanoparticle film 76. Because the nanoparticle film 76 contains many spaces between the nanoparticles, it cannot prevent the diffusion of outside air, allowing oxygen to penetrate into the red wavelength conversion section 32 and causing the conversion efficiency of the red wavelength conversion section 32 to deteriorate over time. To prevent this, a dense AZO film 75 is disposed on top of the nanoparticle film 76. With this structure, the AZO film 75 can block oxygen in the air from penetrating into the red wavelength conversion section 32. The nanoparticle film 76 has a large nanoparticle surface, allowing oxygen to be adsorbed onto the nanoparticle surface.

[0050] As in this configuration, the nanoparticle film 76, which is an aggregate of nanoparticles and contains a large amount of nanoparticle surfaces inside, functions as an oxygen absorbing film, and can achieve the same effect as in the first embodiment.

[0051] [Embodiment 4] Another embodiment of the present invention will be described below with reference to Fig. 12. For ease of explanation, components having the same functions as those described in the previous embodiment are denoted by the same reference numerals, and their description will not be repeated. In the image display element 200c of embodiment 4, the configuration of the excitation light-emitting element and the partition wall differs from that of embodiment 1. In all other respects, it is the same as embodiment 1.

[0052] 12, the dielectric multilayer film 74 is disposed continuously across the pixels 5c, but may be divided and formed for each pixel 5c, as in the second embodiment.

[0053] In the configuration of this embodiment shown in FIG. 12, the excitation light-emitting element 105c is individually divided between the pixels 5c. That is, the bodies 19 made of the nitride semiconductor layer 14 constituting the excitation light-emitting element 105c are separated from each other and do not have a continuous portion like the continuous N-side layer 11C in Embodiment 1. This structure may be necessary to prevent optical crosstalk caused by blue light leaking to adjacent pixels. In this configuration, a transparent electrode 30 (a second oxygen absorption film, a second inorganic oxide thin film) is required instead of the continuous N-side layer 11C in Embodiment 1. In this configuration, the transparent electrode 30 is made of an AZO film. By using a conductive AZO film, it can function as both the transparent electrode 30 and an oxygen absorption film. That is, in this configuration, the red wavelength conversion unit 32 has a dielectric multilayer film 74 disposed on the red light-emitting surface and an AZO film disposed on the surface (underside) facing the excitation light-emitting element 105c. The transparent electrode 30 is not limited to a single layer film, and a transparent conductive layer such as ITO may be arranged on the side in contact with the N-side layer 11, and an oxygen absorbing film such as AZO may be arranged on the side in contact with the red wavelength conversion section 32.

[0054] Preferably, the body sidewalls 19S (sidewalls) of the body 19 of the excitation light-emitting element 105c are inclined so that the inclination angle θe is approximately 30 to 60 degrees around the light-emitting layer 12, and also approximately 85 to 70 degrees around the N-side layer 11. This shape of the body 19 increases the amount of blue light flowing from the excitation light-emitting element 105c into the red wavelength conversion section 32, thereby improving the blue light absorption efficiency in the red wavelength conversion section 32. Although not shown in FIG. 12, these inclined surfaces can be covered with a transparent insulating film, and the outside of that can be further covered with a highly reflective metal film such as aluminum or silver, thereby further improving the blue light absorption efficiency.

[0055] Furthermore, the partitions 34c separating the red wavelength conversion sections 32 are not formed of a single material as in the first embodiment, but are formed of a partition base material 35 and a partition reflector 36 (light-reflecting material) covering the surface thereof. The surface of the partition reflector 36 on the side surface of the partition 34c is a reflective surface, which is the partition side surface 34S. When the thickness of the partition reflector 36 is substantially constant, the inclination angle θw of the reflective surface is approximately equal to the inclination angle of the side surface of the partition base material 35. The partition base material 35 can be formed of an inorganic material such as SiO2 or SiN, or a resin material such as a photoresist material. The partition reflector 36 can be formed of, for example, a highly reflective metal film. In this way, the partitions 34c may be formed of multiple materials as long as the partition side surface 34S is a good reflective surface.

[0056] To construct the partition walls 34c using a single reflecting material, as in the first embodiment, a metal film greater than the height of the partition walls 34c must be deposited and then processed into the partition walls 34c with inclined surfaces using photolithography or dry etching. Because the height of the partition walls 34c can be several micrometers, a very thick metal film is required. However, the surface of such a thick metal film is highly uneven, making precise alignment with the underlying layer difficult. Furthermore, since it is desirable that the bottom of the partition wall side surface 34S does not cover the light-emitting surface 130c of the excitation light-emitting element 105c, the smaller the pixel size of the image display element 200c, the more precisely the partition walls 34c must be aligned with the light-emitting surface 130c of the excitation light-emitting element 105c. Therefore, the above problem can be avoided by forming the center portion of the partition walls 34c (the partition wall base material 35) using a transparent material with minimal surface unevenness, which facilitates precise alignment, and then covering the surface with the partition wall reflecting material 36.

[0057] As described above, when miniaturizing the pixels 5c in the image display element 200c and suppressing optical crosstalk, the structure shown in FIG. 12 may be necessary.

[0058] This embodiment can also achieve the same effects as those of embodiment 1. In particular, by arranging oxygen absorbing films on both the upper and lower surfaces of the red wavelength converting portion 32, the effect of recovering the conversion efficiency can be further improved.

[0059] [Embodiment 5] Another embodiment of the present invention will be described below with reference to Figures 13 and 14. For ease of explanation, components having the same functions as those described in the previous embodiments are denoted by the same reference numerals, and their description will not be repeated. Image display element 200d of embodiment 5 is a full-color display element, unlike the previous monochrome image display elements.

[0060] Fig. 13 is a cross-sectional view of a pixel region 1d of an image display element 200d according to Embodiment 5. Fig. 14 is a plan view of a pixel region 1d of the image display element 200d. Fig. 13 shows a cross-sectional view of the portion taken along line BB in Fig. 14.

[0061] 14, when the pixel region 1d of the image display element 200d is viewed from above, a plurality of pixels 5d are arranged in an array. Each pixel 5d includes two green subpixels 8, each of which includes a green micro light emitting element 100G, a blue subpixel 6, each of which includes a blue micro light emitting element 100B, and a red subpixel 7, each of which includes a red micro light emitting element 100R. The types and number of subpixels constituting the pixel 5d are not limited to these. The image display element 200d includes a plurality of blue micro light emitting elements 100B, red micro light emitting elements 100R, and green micro light emitting elements 100G, and a drive circuit board 50d.

[0062] The drive circuit board 50d supplies current to the blue micro light emitting element 100B, the red micro light emitting element 100R, and the green micro light emitting element 100G in the pixel region 1d to control their light emission. The red micro light emitting element 100R and the green micro light emitting element 100G each have an excitation light emitting element 105d that emits blue light, a red wavelength conversion portion 32d, and a green wavelength conversion portion 33, similar to the micro light emitting element 100 of the first embodiment. The blue micro light emitting element 100B has a transparent portion 31 instead of the red wavelength conversion portion 32d. The red wavelength conversion portion 32d and the green wavelength conversion portion 33 contain wavelength conversion nanoparticles that absorb blue light, which is excitation light, and emit red light and green light, respectively. The transparent portion 31 transmits blue light intact, and therefore does not contain wavelength conversion nanoparticles that absorb and wavelength convert excitation light. The transparent section 31, the red wavelength-converting section 32d, and the green wavelength-converting section 33 may each contain scattering particles that do not absorb the excitation light but scatter the excitation light.

[0063] The excitation light-emitting element 105d, the transparent section 31, the red wavelength-converting section 32d, and the green wavelength-converting section 33 are all surrounded by a partition wall 34d. The partition wall 34d is disposed at the boundary between adjacent sub-pixels, and in this configuration, a partition wall reflector 36 is disposed on the surface of a partition wall base material 35 having inclined side surfaces. The partition wall base material 35 is, for example, a resin material obtained by hard-baking a resist pattern formed by photolithography. The partition wall reflector 36 is a thin film of aluminum or silver with high reflectivity. The surface of the partition wall reflector 36 is inclined so as to open toward the light emission direction. The angle between the surface of the partition wall reflector 36 and the horizontal plane is defined as the inclination angle θw. The smaller the inclination angle θw, the better.

[0064] The excitation light-emitting element 105d includes a main body 19d formed by dividing the nitride semiconductor layer 14, an N-electrode 23N (first electrode), and a transparent electrode 30 (second electrode). The transparent electrode 30 (second oxygen absorbing film, second inorganic oxide thin film) is disposed on the light emitting surface 130 side of the nitride semiconductor layer 14, and the N-electrode 23N is disposed on the drive circuit substrate 50d side. The N-electrode 23N is connected to an N-drive electrode 51 on the drive circuit substrate 50d. The transparent electrode 30 is connected to a metallic partition reflector 36 constituting the partition 34d, and is connected to a P-drive electrode 52 on the drive circuit substrate 50d, outside the pixel region 1d, via the partition reflector 36. The amount of light emitted by the excitation light-emitting element 105d is controlled according to the amount of current flowing between the N-drive electrode 51 and the P-drive electrode 52 on the drive circuit substrate 50d.

[0065] The nitride semiconductor layer 14 constituting the main body 19d is formed by laminating an N-side layer 11, a light emission layer 12, and a P-side layer 13 in this order from the drive circuit board 50d side. The light emission layer 12 is preferably disposed on the upper surface side of the nitride semiconductor layer 14. The bottom surface of the main body 19d is preferably covered with an N-electrode 23N. If there is a portion not covered by the N-electrode 23N, light will leak from the main body 19d to the drive circuit board 50d side, resulting in a decrease in light emission efficiency and optical crosstalk.

[0066] A highly reflective material such as aluminum or silver is preferably disposed on the N-side layer 11 side of the N-electrode 23N. Furthermore, aluminum and silver easily form ohmic contact with the N-side layer 11, making them suitable for electrodes connected to the N-side layer 11. The configuration in which the N-side layer 11 is disposed on the drive circuit substrate 50d side, as shown in FIG. 13, is advantageous in that it makes it easy to dispose a highly reflective metal film on the underside of the nitride semiconductor layer 14. In a configuration in which the P-side layer 13 is disposed on the drive circuit substrate 50d side, a low-reflective metal material such as titanium or palladium must be disposed on the underside of the nitride semiconductor layer 14 to form an ohmic contact between the P-side layer 13 and the drive circuit substrate 50d. This increases light absorption at the bottom surface and reduces light emission efficiency.

[0067] An opening (P contact hole 18P) is present on the top surface of the main body 19d, where the transparent insulating film 20 has been removed. The P contact hole 18P connects the P-side layer 13 and the transparent electrode 30. The transparent electrode 30 may be an oxide semiconductor, such as ITO (Indium-Tin-Oxide), IZO (Indium-Zinc-Oxide), or AZO, or a silver nanofiber film. Transparent electrode materials such as ITO can easily form ohmic contact with the P-side layer 13. To reduce absorption of excitation light, the transparent electrode 30 is preferably as thin as possible. By providing the oxide semiconductor with oxygen absorption functionality, oxygen absorption films can be disposed on both the top and bottom surfaces of the wavelength conversion section, as in the fourth embodiment, to further promote recovery of conversion efficiency. Alternatively, the transparent electrode 30 may have a multi-layer structure. For example, a highly conductive ITO film may be disposed on the side in contact with the P-side layer 13, and an AZO film may be disposed thereon as an oxygen absorbing film in contact with the wavelength conversion portion.

[0068] The entire side surface of the main body 19d is covered with a transparent insulating film 20. If a portion of the side surface of the main body 19d is covered with a metal material or a light-absorbing resin material, for example, light extraction from the main body 19d to the red wavelength conversion section 32d is hindered, resulting in a decrease in luminous efficiency. It is preferable that the side surface of the main body 19d be nearly perpendicular to the horizontal plane. By making the side surface nearly perpendicular, the area of ​​the light-emitting layer 12 can be made as large as possible, and resistance to processing damage can be improved.

[0069] As shown in FIG. 13 , the excitation light emitting element 105d is surrounded by the partition wall 34d, which is taller than the excitation light emitting element 105d. The entire excitation light emitting element 105d, except for its bottom surface, is covered by the transparent portion 31, the red wavelength conversion portion 32d, or the green wavelength conversion portion 33. For example, in order for the red wavelength conversion portion 32d to efficiently absorb the excitation light emitted by the excitation light emitting element 105d, it is preferable that the red wavelength conversion portion 32d above the excitation light emitting element 105d be thick. Furthermore, the red wavelength conversion portion 32d must cover the periphery of the excitation light emitting element 105d. That is, by having the red wavelength conversion portion 32d fill the space between the excitation light emitting element 105d and the partition wall 34d, the excitation light can be efficiently absorbed by the red wavelength conversion portion 32d.

[0070] 13, the image display element 200d includes a plurality of blue micro light-emitting elements 100B, red micro light-emitting elements 100R, and green micro light-emitting elements 100G, each of which has only an N-electrode 23N in the pixel region 1d. In this configuration, the N-electrode 23N covers a wide area of ​​the subpixel, excluding the periphery of the subpixel. This allows for a wide overlap area between the partition reflector 36 and the N-electrode 23N in a planar view. This eliminates the exposed area of ​​the drive circuit board 50d in a planar view, reducing light leakage to the drive circuit board 50d.

[0071] In this configuration, a blue micro light emitting element 100B having a transparent portion 31 is used as the blue subpixel 6 instead of a wavelength conversion portion. The reason for this is that light emission efficiency is higher when light is emitted via the transparent portion 31 than when light is emitted directly into the air from the excitation light emitting element 105d. The transparent portion 31 may include a first layer 31F and a second layer 31S. By making the refractive index of the first layer 31F lower than that of the second layer 31S, the light emission efficiency of the blue micro light emitting element 100B can be further improved.

[0072] 13, the red wavelength conversion portion 32d of the red micro light emitting element 100R may also be composed of a first layer 32F and a second layer 32S. The green wavelength conversion portion 33 of the green micro light emitting element 100G may also be composed of a first layer 33F and a second layer 33S. The refractive indexes of the first layer 32F and the first layer 33F are lower than the refractive indexes of the second layer 32S and the second layer 33S, respectively, and the first layer 32F and the first layer 33F may be a transparent resin that does not contain a wavelength conversion material.

[0073] In a structure such as the image display element 200d, the second layer is formed first, followed by the first layer, during the manufacturing process of the wavelength conversion section and the transparent section. The thickness of the first layer may be the same for each subpixel, or may vary. When the thickness of the second layer varies between subpixels, simultaneously forming the first layer allows the height of the light emitting surface 130 to be the same between the subpixels. This has the advantage of facilitating the formation of an oxygen absorbing film.

[0074] In this configuration, the oxygen absorbing film includes a dielectric multilayer film 74d, which has the property of reflecting excitation light and transmitting long wavelength light such as red light and green light, and therefore no oxygen absorbing film is disposed in the blue subpixel 6. However, when a film without such a filter function is used as the oxygen absorbing film, it may be disposed continuously over the entire surface of the pixel region 1d.

[0075] As described above, the same effects as those of the first embodiment can be achieved with the configuration of the image display element 200d.

[0076] [Embodiment 6] Another embodiment of the present invention will be described below with reference to Figure 15. For ease of explanation, components having the same functions as those described in the previous embodiment will be denoted by the same reference numerals, and their description will not be repeated. This embodiment is similar to the image display element 200d of embodiment 5, but differs in that an oxygen absorption film is also disposed on the sides of the wavelength conversion section (green micro-light-emitting element 100eG, red micro-light-emitting element 100eR, and blue micro-light-emitting element 100eB).

[0077] In this configuration, the transparent electrode 30 (second oxygen absorbing film, third oxygen absorbing film, second inorganic oxide thin film, third inorganic oxide thin film) is formed covering the surface of the partition wall 34e. Therefore, the red wavelength conversion section 32d and the green wavelength conversion section 33 are in contact with the transparent electrode 30 on their bottom surfaces in contact with the excitation light emitting element 105d and on their side surfaces in contact with the partition wall 34e. Therefore, as described in the fifth embodiment, adding an oxygen absorbing function to the transparent electrode 30 can further enhance the recovery of conversion efficiency. By arranging a dielectric multilayer film 74d, an AZO film 75, or a combination thereof on the surface of the red wavelength conversion section 32d or the green wavelength conversion section 33 on the light emitting surface 130 side, an oxygen absorbing film can be arranged on the entire surface of the red wavelength conversion section 32d or the green wavelength conversion section 33. Therefore, a very strong recovery effect can be achieved.

[0078] The transparent electrode 30 may have a multi-layer structure. For example, a highly conductive ITO film may be disposed on the side in contact with the P-side layer 13, and an AZO film may be disposed thereon as an oxygen absorbing film in contact with the wavelength converting portion.

[0079] In the fourth and fifth embodiments, an oxygen absorbing film may be disposed on the underside and side surfaces of the wavelength conversion section in addition to the light emitting surface thereof, and an oxygen absorbing film such as an AZO film may be deposited on the partition wall 34c and the transparent electrode 30, or on the partition wall 34d and the transparent electrode 30, before the wavelength conversion section is formed.

[0080] As described above, the same effects as those of the first embodiment can be achieved with the configuration of the image display element 200e.

[0081] 〔summary〕 The micro light-emitting element (100) according to aspect 1 of the present invention is a micro light-emitting element comprising a micro LED element (excitation light-emitting element 105) that emits excitation light, and a wavelength conversion section (red wavelength conversion section 32) that includes nanoparticles (wavelength conversion nanoparticles) that absorb the excitation light and emit light having a longer wavelength than the excitation light, and has at least one or more laminated layers including an oxygen absorption film (dielectric multilayer film 74) on the light-emitting side surface of the wavelength conversion section.

[0082] According to the above configuration, the oxygen absorbing film included in the laminate can absorb the oxygen contained in the wavelength conversion portion, thereby suppressing non-radiative recombination of the nanoparticles in the wavelength conversion portion, which absorb excitation light and emit light with a longer wavelength than the excitation light. As a result, the conversion efficiency of the wavelength conversion portion can be improved, and the power consumption of the micro light-emitting element can be reduced.

[0083] In the micro light-emitting element (100) according to aspect 2 of the present invention, in the above aspect 1, the oxygen absorbing film may be made of an inorganic oxide, and the composition of the inorganic oxide may deviate from the stoichiometric state in the direction of oxygen deficiency.

[0084] According to the above-mentioned configuration, the composition of the inorganic oxide constituting the oxygen absorbing film is deviated from the stoichiometric state in the direction of oxygen deficiency, and therefore the inorganic oxide can absorb oxygen contained in the wavelength converting portion, making it suitable for use as the oxygen absorbing film.

[0085] In the micro light emitting device (100) according to a third aspect of the present invention, in the second aspect, the oxygen absorbing film may be in an amorphous state.

[0086] According to the above-described structure, in an amorphous state, there are generally many dangling bonds, and oxygen vacancies tend to occur in oxides, which allows the oxygen absorbing film to absorb more oxygen contained in the wavelength converting portion.

[0087] In the micro light emitting device (100) according to a fourth aspect of the present invention, in the second or third aspect, the oxygen absorbing film may be made of AZO (AZO film 75).

[0088] According to the above-described configuration, even if the film is thinner than the dielectric multilayer film including the oxygen absorbing film, for example, the conversion efficiency of the wavelength converting portion can be improved.

[0089] In the micro light-emitting element (100) according to aspect 5 of the present invention, in aspect 2 or 3, the laminate may have a dielectric multilayer film (74), and the dielectric multilayer film may include a plurality of the oxygen absorbing films.

[0090] According to the above configuration, the dielectric multilayer film has the property of reflecting excitation light emitted by the micro LED element and transmitting wavelength light, so that, for example, it is possible to reduce emission of blue light and increase the amount of emitted red light. Therefore, by including the oxygen absorbing film in the dielectric multilayer film, it is possible to achieve the above effects and improve the conversion efficiency of the wavelength conversion section.

[0091] In the micro light-emitting element (100) according to aspect 6 of the present invention, in either aspect 2 or 3, the laminate may have an AZO film (75) in contact with the wavelength conversion section (red wavelength conversion section 32), and may further have a dielectric multilayer film (74) thereon.

[0092] According to the above configuration, by using the AZO film and the dielectric multilayer film as a laminate, the conversion efficiency of the wavelength conversion section can be improved more than when each is used alone.

[0093] In the micro light-emitting element (100) according to aspect 7 of the present invention, in either aspect 2 or 3, the laminate may have a dielectric multilayer film (74) in contact with the wavelength conversion section (red wavelength conversion section 32), and may further have an AZO film (75) thereon.

[0094] According to the above configuration, the conversion efficiency of the wavelength conversion portion can be improved more than a laminate having an AZO film in contact with the wavelength conversion portion and a dielectric multilayer film thereon.

[0095] In the micro light emitting device (100b) according to an eighth aspect of the present invention, in the first aspect, the oxygen absorbing film may be a nanoparticle film (76).

[0096] According to the above-described configuration, by using a nanoparticle film, which is an aggregate of nanoparticles, as the oxygen absorbing film, it is possible to increase the area that reacts with oxygen, thereby facilitating the absorption of oxygen.

[0097] In the micro light-emitting element (100a, 100c, 100d, 100e) according to aspect 9 of the present invention, in any of aspects 1 to 8, a second oxygen absorbing film (second AZO film 77, transparent electrode 30) may be further provided in contact with the surface of the wavelength converting portion (transparent portion 31, red wavelength converting portion 32, 32d, green wavelength converting portion 33) on the side in contact with the micro LED element (excitation light-emitting element 105).

[0098] According to the above configuration, the oxygen absorbing film can be disposed on the side of the wavelength conversion unit that contacts the micro LED element. This increases the area of ​​the oxygen absorbing film that contacts the wavelength conversion unit, further improving the conversion efficiency. As a result, the recovery of the conversion efficiency of the wavelength conversion unit can be further strengthened without significantly increasing costs.

[0099] In the micro light-emitting element (100a-100e) according to aspect 10 of the present invention, in any of aspects 1 to 9, a third oxygen absorbing film (second AZO film 77, transparent electrode 30) may be further provided in contact with the side surface of the wavelength converting portion (transparent portion 31, red wavelength converting portion 32-32d, green wavelength converting portion 33).

[0100] According to the above configuration, the oxygen absorbing film can be disposed on the side surfaces of the wavelength converting unit. This increases the surface area of ​​the oxygen absorbing film that is in contact with the wavelength converting unit, thereby further improving the conversion efficiency. As a result, the recovery of the conversion efficiency of the wavelength converting unit can be further strengthened without significantly increasing costs.

[0101] The micro light-emitting element (100) according to aspect 11 of the present invention is a micro light-emitting element comprising a micro LED element (excitation light-emitting element 105) that emits excitation light, and a wavelength conversion section (red wavelength conversion section 32) that includes nanoparticles (wavelength conversion nanoparticles) that absorb the excitation light and emit light having a longer wavelength than the excitation light, and at least on the light-emitting side surface of the wavelength conversion section, it has one or more laminated layers including an inorganic oxide thin film (dielectric multilayer film 74), and the inorganic oxide thin film increases over time the conversion efficiency of the nanoparticles that convert the excitation light into light having a longer wavelength than the excitation light.

[0102] According to the above configuration, the micro light-emitting element has one or more laminated layers including an inorganic oxide thin film on the light-emitting side of the wavelength conversion unit containing nanoparticles, which increases over time the conversion efficiency of the nanoparticles in converting excitation light into light with a longer wavelength than the excitation light. Therefore, the conversion efficiency of the wavelength conversion unit increases over time due to the inorganic oxide thin film. As a result, the power consumption of the micro light-emitting element can be reduced.

[0103] In the micro light-emitting element (100) of aspect 12 of the present invention, in the above-mentioned aspect 11, the inorganic oxide thin film (dielectric multilayer film 74) may continuously cover the entire surface of the wavelength conversion section (red wavelength conversion section 32) in the light emission direction.

[0104] According to the above-mentioned configuration, the inorganic oxide thin film continuously covers the entire surface of the wavelength conversion section in the light emission direction, and therefore the area of ​​the inorganic oxide thin film in contact with the wavelength conversion section is increased, thereby improving the conversion efficiency. In addition, the inorganic oxide thin film can prevent the intrusion of oxygen and moisture from the outside.

[0105] In the micro light emitting device (100) according to a thirteenth aspect of the present invention, in the eleventh or twelfth aspect, the composition of the inorganic oxide thin film may deviate from the stoichiometric state in the direction of oxygen deficiency.

[0106] According to the above configuration, the composition of the inorganic oxide thin film deviates from the stoichiometric state in the direction of oxygen deficiency, which allows the absorption of oxygen contained in the wavelength conversion portion and suppresses non-radiative recombination of nanoparticles, thereby improving the conversion efficiency of the wavelength conversion portion.

[0107] In the micro light emitting device (100) according to a fourteenth aspect of the present invention, in any one of the eleventh to thirteenth aspects, the inorganic oxide thin film may include an amorphous state.

[0108] According to the above-mentioned structure, if an amorphous state is included, there are generally many dangling bonds, and oxygen deficiency is likely to occur in the oxide, which allows the inorganic oxide thin film to absorb more oxygen contained in the wavelength converting portion.

[0109] In the micro light emitting device (100) according to a fifteenth aspect of the present invention, in any one of the eleventh to fourteenth aspects, the inorganic oxide thin film may be made of AZO (AZO film 75).

[0110] According to the above-described configuration, even if the film is thinner than a dielectric multilayer film containing an inorganic oxide thin film, for example, the conversion efficiency of the wavelength conversion section can be improved.

[0111] In a micro light-emitting element (100) according to aspect 16 of the present invention, in any of aspects 11 to 15, the laminate may have a dielectric multilayer film (74), and the dielectric multilayer film may include a plurality of the inorganic oxide thin films.

[0112] According to the above configuration, the dielectric multilayer film has the property of reflecting excitation light emitted by the micro LED element and transmitting wavelength light, so that, for example, it is possible to reduce the emission of blue light and increase the amount of emitted red light. Therefore, by including an inorganic oxide thin film in the dielectric multilayer film, it is possible to achieve the above effects while improving the conversion efficiency of the wavelength conversion section.

[0113] In the micro light-emitting element (100) according to aspect 17 of the present invention, in any of aspects 11 to 16, the laminate may have an AZO film (75) on the wavelength conversion section (red wavelength conversion section 32) side, and may further have a dielectric multilayer film (74) thereon.

[0114] According to the above configuration, by using the AZO film and the dielectric multilayer film as a laminate, the conversion efficiency of the wavelength conversion section can be improved more than when each is used alone.

[0115] In the micro light-emitting element (100) according to aspect 18 of the present invention, in any of aspects 11 to 16, the laminate may have a dielectric multilayer film (74) on the wavelength conversion section (red wavelength conversion section 32) side, and may further have an AZO film (75) thereon.

[0116] According to the above configuration, the conversion efficiency of the wavelength conversion section can be improved more than in a laminate having an AZO film on the wavelength conversion section side and a dielectric multilayer film thereon.

[0117] The micro light-emitting element (100a, 100c, 100d, 100e) according to aspect 19 of the present invention may further include a second inorganic oxide thin film (second AZO film 77, transparent electrode 30) in contact with the surface of the wavelength conversion portion (transparent portion 31, red wavelength conversion portion 32, 32d, green wavelength conversion portion 33) on the side in contact with the micro LED element (excitation light-emitting element 105) in any of aspects 11 to 18.

[0118] According to the above configuration, the inorganic oxide thin film can be disposed on the side of the wavelength conversion section that contacts the micro LED element. This increases the area of ​​the inorganic oxide thin film that contacts the wavelength conversion section, thereby further improving the conversion efficiency. As a result, the recovery of the conversion efficiency of the wavelength conversion section can be further enhanced without significantly increasing costs.

[0119] In the micro light-emitting element (100a-100e) according to aspect 20 of the present invention, in any of aspects 11 to 19, a third inorganic oxide thin film (second AZO film 77, transparent electrode 30) may be further provided in contact with the side surface of the wavelength converting portion (transparent portion 31, red wavelength converting portion 32-32d, green wavelength converting portion 33).

[0120] According to the above configuration, an inorganic oxide thin film can be disposed on the side surface of the wavelength conversion section. This increases the surface area of ​​the inorganic oxide thin film that is in contact with the wavelength conversion section, thereby further improving the conversion efficiency. As a result, the recovery of the conversion efficiency of the wavelength conversion section can be further enhanced without significantly increasing costs.

[0121] An image display element (200) according to aspect 21 of the present invention is an image display element comprising micro light-emitting elements (100) arranged in an array, and a drive circuit board (50) including a drive circuit that supplies current to the micro light-emitting elements to cause them to emit light, wherein the micro light-emitting elements comprise excitation light-emitting elements (105) that emit excitation light, and a wavelength conversion unit (red wavelength conversion unit 32) that absorbs the excitation light and emits light having a longer wavelength than the excitation light, the excitation light-emitting elements and the wavelength conversion unit are stacked in this order on the drive circuit board, the micro light-emitting elements emit light having a longer wavelength than the excitation light upward, in the opposite direction to the drive circuit board, a partition wall (34) is arranged on the side of the wavelength conversion unit, and an oxygen absorption film (dielectric multilayer film 74) is arranged at least on the surface of the wavelength conversion unit in the light emission direction.

[0122] According to the above configuration, in the micro light-emitting element of the image display element, the oxygen absorption film can absorb oxygen contained in the wavelength conversion portion, thereby suppressing non-radiative recombination in the wavelength conversion portion, which absorbs excitation light and emits light with a longer wavelength than the excitation light. As a result, the conversion efficiency of the wavelength conversion portion can be improved, thereby reducing the power consumption of the micro light-emitting element, and therefore reducing the power consumption of the image display element.

[0123] In the image display element (200) according to aspect 22 of the present invention, in the above-mentioned aspect 21, the oxygen absorbing film (dielectric multilayer film 74) may continuously cover the entire surface of the wavelength conversion section in the light emission direction.

[0124] According to the above-mentioned configuration, the oxygen absorbing film continuously covers the entire surface of the wavelength conversion section in the light emission direction, so that the area of ​​the oxygen absorbing film in contact with the wavelength conversion section is increased, thereby improving the conversion efficiency. In addition, the oxygen absorbing film can prevent the intrusion of oxygen and moisture from the outside.

[0125] In the image display element (200a) according to aspect 23 of the present invention, in aspect 21 or 22, the oxygen absorbing film (dielectric multilayer film 74a) may be divided into individual wavelength conversion sections (red wavelength conversion sections 32).

[0126] According to the above configuration, optical crosstalk occurring through the oxygen absorbing film can be prevented.

[0127] In the image display element (200a) according to aspect 24 of the present invention, in aspect 23, the end of the oxygen absorbing film (dielectric multilayer film 74a) divided for each wavelength conversion section (red wavelength conversion section 32) may be located on the upper surface of the partition wall (34).

[0128] According to the above configuration, even when the oxygen absorbing film is divided into each wavelength conversion section, the ends of the divided oxygen absorbing film are located on the partition walls, so that the wavelength conversion sections are not exposed on the light emitting surface side, thereby preventing optical crosstalk that occurs through the oxygen absorbing film while preventing the wavelength conversion sections from coming into contact with external oxygen and moisture without reducing conversion efficiency.

[0129] In an image display element (200a) according to aspect 25 of the present invention, in any one of aspects 21 to 24, the oxygen absorbing film is made of an inorganic oxide, and the composition of the inorganic oxide may deviate from the stoichiometric state in the direction of oxygen deficiency.

[0130] According to the above-mentioned configuration, the composition of the inorganic oxide constituting the oxygen absorbing film is deviated from the stoichiometric state in the direction of oxygen deficiency, and therefore the inorganic oxide can absorb oxygen contained in the wavelength converting portion, making it suitable for use as the oxygen absorbing film.

[0131] In the image display element (200b) according to aspect 26 of the present invention, in the image display element (200b) according to aspect 21, the oxygen absorbing film may be a nanoparticle film (76).

[0132] According to the above-mentioned configuration, by using a nanoparticle film, which is an aggregate of nanoparticles, as the oxygen absorbing film, it is possible to increase the area that reacts with oxygen, thereby facilitating the absorption of oxygen.

[0133] The image display element (200a, 200c, 200d, 200e) of aspect 27 of the present invention, in any of aspects 21 to 26, may further have a second oxygen absorbing film (second AZO film 77, transparent electrode 30) in contact with the surface of the wavelength converting section (transparent section 31, red wavelength converting section 32, 32d, green wavelength converting section 33) on the side in contact with the excitation light emitting element (105).

[0134] According to the above configuration, the oxygen absorbing film can be disposed on the side of the wavelength conversion unit that contacts the excitation light emitting element. This increases the surface area of ​​the oxygen absorbing film that contacts the wavelength conversion unit, thereby further improving the conversion efficiency. As a result, the recovery of the conversion efficiency of the wavelength conversion unit can be further strengthened without significantly increasing costs.

[0135] The image display element (200a-200e) according to aspect 28 of the present invention, in any of aspects 21 to 27, may further have a third oxygen absorbing film (second AZO film 77, transparent electrode 30) in contact with the side surface of the wavelength converting section (transparent section 31, red wavelength converting section 32-32d, green wavelength converting section 33).

[0136] According to the above configuration, the oxygen absorbing film can be disposed on the side surfaces of the wavelength converting unit. This increases the surface area of ​​the oxygen absorbing film that is in contact with the wavelength converting unit, thereby further improving the conversion efficiency. As a result, the recovery of the conversion efficiency of the wavelength converting unit can be further strengthened without significantly increasing costs.

[0137] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. [Explanation of symbols]

[0138] 1, 1c, 1d, 1e pixel area 5, 5c, 5d pixels 6 blue subpixels 7 red subpixels 8 green subpixels 11 N side layer 12 Light-emitting layer 13 P side layer 14 Nitride semiconductor layer 16 Mesa 17 Protective film 18P P contact hole 19, 19d main body 19S Main body side wall 20 Transparent insulating film 23N N electrode 23P P electrode 30 Transparent electrodes (second oxygen absorbing film, third oxygen absorbing film, second inorganic oxide thin film, third inorganic oxide thin film) 31 Transparent part (wavelength conversion part) 32, 32d Red wavelength conversion unit (wavelength conversion unit) 33 Green wavelength conversion unit (wavelength conversion unit) 34, 34c, 34d, 34e bulkhead 35 Partition wall base material 36 Bulkhead reflective material 50, 50d drive circuit board 51 N drive electrode 52 P drive electrode 74, 74a, 74d Dielectric multilayer film (oxygen absorption film, inorganic oxide thin film) 75 AZO film (oxygen absorption film, inorganic oxide thin film) 76 Nanoparticle membranes (oxygen absorption membranes, inorganic oxide thin films) 77 Second AZO film (second oxygen absorbing film, third oxygen absorbing film, second inorganic oxide thin film, third inorganic oxide thin film) 100, 100a, 100b, 100c Micro light emitting element 100B, 100eB Blue Micro Light Emitting Device (Micro Light Emitting Device) 100G, 100eG green micro light emitting element (micro light emitting element) 100R, 100eR Red micro-luminescent element (micro-luminescent element) 105, 105c, 105d Excitation light emitting element (micro LED element) 130 Light emitting surface 200, 200a, 200b, 200c, 200d, 200e Image display element θw Inclination angle of the partition side θe: Inclination angle of the nitride semiconductor side surface near the light-emitting layer

Claims

1. a micro LED (light emitting diode) element that emits excitation light; A wavelength conversion unit including nanoparticles that absorb the excitation light and emit light having a longer wavelength than the excitation light, At least one laminate including a first oxygen absorbing film is provided on the light emitting side surface of the wavelength converting portion, a second oxygen absorbing film on a surface of the wavelength conversion unit facing the micro LED element; the first oxygen absorbing film and the second oxygen absorbing film are made of an inorganic oxide; The micro light-emitting element, characterized in that the second oxygen absorbing film functions as a transparent electrode of the micro LED element.

2. 2. The micro light-emitting element according to claim 1, wherein the composition of the inorganic oxide constituting the first oxygen absorption film is deviated from the stoichiometric state in the direction of oxygen deficiency.

3. The micro light emitting element according to claim 2 , wherein the first oxygen absorbing film is in an amorphous state.

4. 4. The micro light-emitting element according to claim 2, wherein the first oxygen absorbing film is made of AZO (Aluminum doped Zinc Oxide).

5. The micro light-emitting element according to claim 2 or 3, wherein the laminate has a dielectric multilayer film, and the dielectric multilayer film includes a plurality of the first oxygen absorbing films.

6. The micro light-emitting element according to claim 2 or 3, wherein the laminate has an AZO (Aluminum doped Zinc Oxide) film in contact with the wavelength conversion portion, and further has a dielectric multilayer film thereon.

7. The micro light-emitting element according to claim 2 or 3, wherein the laminate has a dielectric multilayer film in contact with the wavelength conversion portion, and further has an AZO (Aluminum doped Zinc Oxide) film thereon.

8. The micro light emitting element according to claim 1 , wherein the first oxygen absorbing film is a nanoparticle film.

9. 9. The micro light-emitting element according to claim 1, further comprising a third oxygen absorbing film in contact with a side surface of the wavelength converting portion.

10. a micro LED element that emits excitation light; A wavelength conversion unit including nanoparticles that absorb the excitation light and emit light having a longer wavelength than the excitation light, At least one laminate including an inorganic oxide thin film constituting a first oxygen absorbing film is provided on the light emitting side surface of the wavelength converting section, a second oxygen absorbing film made of an inorganic oxide on a surface of the wavelength conversion unit facing the micro LED element; The inorganic oxide thin film is characterized in that the nanoparticles in the inorganic oxide thin film increase, over time, the conversion efficiency of converting the excitation light into light having a longer wavelength than the excitation light.

11. The micro light-emitting element according to claim 10 , wherein the inorganic oxide thin film continuously covers the entire surface of the wavelength conversion portion in the light emission direction.

12. 12. The micro light-emitting element according to claim 10, wherein the composition of the inorganic oxide thin film is deviated from the stoichiometric state in the direction of oxygen deficiency.

13. The micro light-emitting element according to claim 10 , wherein the inorganic oxide thin film includes an amorphous state.

14. The micro light-emitting element according to any one of claims 10 to 13, wherein the inorganic oxide thin film is made of AZO (Aluminum doped Zinc Oxide).

15. The micro light-emitting element according to any one of claims 10 to 14, wherein the laminate has a dielectric multilayer film, and the dielectric multilayer film includes a plurality of the inorganic oxide thin films.

16. The micro-light-emitting element according to any one of claims 10 to 15, characterized in that the laminate has an AZO (Aluminum doped Zinc Oxide) film on the wavelength conversion portion side, and further has a dielectric multilayer film on top of that.

17. The micro-light-emitting element according to any one of claims 10 to 15, characterized in that the laminate has a dielectric multilayer film on the wavelength conversion portion side, and further has an AZO (Aluminum doped Zinc Oxide) film thereon.

18. The micro light-emitting element according to any one of claims 10 to 17, wherein the second oxygen absorbing film functions as a transparent electrode of the micro LED element.

19. 19. The micro light-emitting element according to claim 10, further comprising a third inorganic oxide thin film in contact with a side surface of the wavelength converting portion.

20. An image display element, micro light-emitting elements arranged in an array; a driving circuit board including a driving circuit that supplies current to the micro light emitting element to emit light; Including, The micro light-emitting element includes an excitation light-emitting element that emits excitation light, and a wavelength conversion unit that includes nanoparticles that absorb the excitation light and emit light having a wavelength longer than that of the excitation light, The excitation light emitting element and the wavelength conversion unit are stacked in this order on the drive circuit board, and the micro light emitting element emits light having a longer wavelength than the excitation light upward, which is in the opposite direction to the drive circuit board; a partition wall is disposed on a side surface of the wavelength converting unit, a first oxygen absorbing film is disposed at least on a surface of the wavelength converting portion in a light emitting direction; a second oxygen absorbing film is further provided on a surface of the wavelength converting section facing the excitation light emitting element; the first oxygen absorbing film and the second oxygen absorbing film are made of an inorganic oxide; The image display element is characterized in that the first oxygen absorbing film increases, over time, the conversion efficiency with which the nanoparticles convert the excitation light into light having a longer wavelength than the excitation light.

21. 21. The image display element according to claim 20, wherein the first oxygen absorbing film continuously covers the entire surface of the wavelength converting portion in the light emitting direction.

22. 22. The image display element according to claim 20, wherein the first oxygen absorbing film is divided into portions for each of the wavelength converting portions.

23. An image display element, micro light-emitting elements arranged in an array; a driving circuit board including a driving circuit that supplies current to the micro light emitting element to emit light; Including, The micro light-emitting element includes an excitation light-emitting element that emits excitation light, and a wavelength conversion unit that absorbs the excitation light and emits light having a longer wavelength than the excitation light, The excitation light emitting element and the wavelength conversion unit are stacked in this order on the drive circuit board, and the micro light emitting element emits light having a longer wavelength than the excitation light upward, which is in the opposite direction to the drive circuit board; a partition wall is disposed on a side surface of the wavelength converting unit, a first oxygen absorbing film is disposed at least on a surface of the wavelength converting portion in a light emitting direction; the first oxygen absorbing film is divided into individual wavelength converting portions, An image display element, characterized in that an end portion of the first oxygen absorbing film divided for each of the wavelength conversion portions is located on an upper surface of the partition wall.

24. 23. The image display element according to claim 20, wherein the composition of the inorganic oxide constituting the first oxygen absorbing film is deviated from the stoichiometric state in the direction of oxygen deficiency.

25. 21. The image display element according to claim 20, wherein the first oxygen absorbing film is a nanoparticle film.

26. An image display element, comprising: micro light-emitting elements arranged in an array; a driving circuit board including a driving circuit that supplies current to the micro light emitting element to emit light; Including, The micro light-emitting element includes an excitation light-emitting element that emits excitation light, and a wavelength conversion unit that absorbs the excitation light and emits light having a longer wavelength than the excitation light, The excitation light emitting element and the wavelength conversion unit are stacked in this order on the drive circuit board, and the micro light emitting element emits light having a longer wavelength than the excitation light upward, which is in the opposite direction to the drive circuit board; a partition wall is disposed on a side surface of the wavelength converting unit, a first oxygen absorbing film is disposed at least on a surface of the wavelength converting portion in a light emitting direction; a second oxygen absorbing film is further provided on a surface of the wavelength converting section facing the excitation light emitting element; the first oxygen absorbing film and the second oxygen absorbing film are made of an inorganic oxide; The image display element is characterized in that the second oxygen absorbing film functions as a transparent electrode of the excitation light emitting element.

27. 27. The image display element according to claim 20, further comprising a third oxygen absorbing film in contact with a side surface of the wavelength converting portion.

Images