CN112103308A - Color conversion apparatus and manufacturing method thereof, micro LED display panel and manufacturing method thereof - Google Patents

Abstract

The color conversion device (20) has a substrate (22) and a light-emitting layer (21) located over the substrate (22) and containing a light-emitting material. The color conversion device (20) has: a first partition wall (23) which is in contact with the light-emitting layer (21) and defines a light-emitting region where the light-emitting layer (21) emits light; and a second partition wall (24) which is in contact with the light-emitting layer (21) and defines a formation region for forming the light-emitting layer (21). The contact area between the light-emitting layer (21) and the first partition (23) is larger than the contact area between the light-emitting layer (21) and the second partition (24). Thus, a color conversion device (20) capable of achieving both suppression of reduction in light emission characteristics and cost reduction can be provided.

Description

Color conversion apparatus and manufacturing method thereof, micro LED display panel and manufacturing method thereof

Technical Field

The present disclosure relates to a color conversion device, a micro LED display panel, a method of manufacturing the color conversion device, and a method of manufacturing the micro LED display panel.

Background

As a next-generation display panel, development of a quantum dot display panel having a light emitting layer made of a quantum dot material is advancing. Quantum dots are special semiconductors of very small size, down to 2 to 10 nm in diameter (equivalent to fractions of 10 to 50 atoms). Such a substance having a minute size has a property different from that of a general substance. For example, quantum dots can control the band gap by changing only the particle size. In addition, since the emission peak wavelength of the quantum dot depends on the band gap, the emission peak wavelength of the quantum dot can be adjusted very precisely. That is, the emission peak wavelength of the quantum dot can be changed by changing only the particle diameter. Specifically, the emission peak wavelength of the quantum dot is shifted to the shorter wavelength side as the particle diameter is smaller, and the emission peak wavelength of the quantum dot is shifted to the longer wavelength side as the particle diameter is larger. Further, the emission spectrum of the quantum dot has a sharp peak, and thus the half-value width of the emission peak wavelength of the quantum dot is very small. Specifically, the emission spectrum of the quantum dot is several 10 nm or less.

That is, if quantum dot materials are used as the materials of the red light emitting layer, the green light emitting layer, and the blue light emitting layer, the half-value width of each emission peak wavelength of red light, green light, and blue light can be reduced. Thereby, a display panel having high color gamut characteristics can be realized. As a result, if a quantum dot material is used for the light-emitting layer, the performance of the display panel can be dramatically improved.

Further, since the luminance is very high, the quantum dot display panel is excellent in visibility outdoors. Therefore, the quantum dot display panel is suitable for a portable telephone, a display for vehicle use, a head mount display, or the like. In particular, since the display is expected to require a pixel resolution of 350ppi (pixel per inch) or more in the future, effective use of a quantum dot display panel is expected.

In recent years, attention has been paid to a method for manufacturing a display panel using an ink jet method. For example, in the case of forming each of a red light-emitting layer, a blue light-emitting layer, and a green light-emitting layer, or a hole injection layer in an organic EL display panel, ink containing an organic EL material is applied to a region (opening) surrounded by partition walls called banks, and a solvent of the ink is dried. That is, a light-emitting layer and the like are formed by an ink-jet method. This enables formation of a light-emitting layer or the like in the air, as compared with formation of a light-emitting layer or the like by a conventional vacuum deposition method.

Further, the organic EL material constituting the light-emitting layer is very expensive. For example, when a light-emitting layer is formed by a vacuum deposition method, an organic EL material adheres to a wall surface of a chamber of a deposition apparatus. Therefore, a large amount of waste organic EL material is generated, and the use efficiency of the material is lowered. This increases the cost of the organic EL display panel. In contrast, when the light-emitting layer is formed by an ink-jet method, the light-emitting layer can be formed in the air, and thus the light-emitting layer can be formed in an energy-saving manner. Further, according to the ink jet method, ink containing an organic EL material can be applied in a color-separated manner only at a predetermined place. Thus, a low-cost organic EL display panel can be realized.

In recent years, as well as inks containing organic EL materials, inks containing the quantum dot materials have been extensively studied for manufacturing methods of applying the materials in a color-separated manner by an ink jet method. As a typical quantum dot material, for example, an inorganic material such as cadmium-selenium or indium-phosphorus is used as a core. The shell around the core of the quantum dot material may be made of a material such as zinc sulfide. Further, in order to achieve stability as an ink, there is also a quantum dot material in which a ligand is formed around a shell.

For example, international publication No. 2016/010077 (hereinafter referred to as "patent document 1") discloses a method of manufacturing a device used in an organic EL display panel or a quantum dot display panel using an inkjet method.

Fig. 13 shows a cross-sectional view of the apparatus disclosed in patent document 1.

As shown in fig. 13, the apparatus disclosed in patent document 1 applies ink to a region (opening) surrounded by partition walls 24X formed on a substrate 22X by an ink jet method. Thereby, the functional film 21X corresponding to the function of the applied ink is formed in the opening. That is, if the device disclosed in patent document 1 is used for a display panel, the region surrounded by the partition walls constitutes a pixel (pixel), and the functional film 21X becomes a light-emitting layer.

However, when the device disclosed in patent document 1 is used for a display panel, the interval of the region surrounded by the partition wall 24X, which is disposed in the surface of the substrate 22X and becomes a pixel, is narrowed. That is, when the resolution of the pixel is to be increased, the landing position of the ink flowing out to the region surrounded by the partition wall 24X may be deviated. As a result, ink may be mixed into undesired pixels, and color mixing may occur.

Hereinafter, a case where the resolution of a pixel of a target display panel is 400ppi, for example, will be specifically described.

In this case, in a device including a light-emitting layer and a partition wall used in a display panel, the distance between pixels and the width of the partition wall are as shown in fig. 1A and 1B.

Fig. 1A is a plan view showing an example of a device configuration used for a display panel having a pixel resolution of 400 ppi. FIG. 1B is a cross-sectional view taken along line 1B-1B of FIG. 1A. In detail, fig. 1B shows a case where ink is caused to flow out to the pixels of the apparatus shown in fig. 1A. Fig. 1B shows a state before the light-emitting layer 21Y shown in fig. 1A is formed.

The display panel shown in fig. 1A and 1B includes light-emitting layers 21Y provided at positions corresponding to respective pixels of red (R), green (G), and blue (B), and partition walls 24Y surrounding the respective light-emitting layers 21Y. The distance between the pixels of the light-emitting layers 21Y of the same color is about 63 μm, and the distance between the pixels of 2 light-emitting layers 21Y adjacent to each other in different colors is 21 μm. The diameter of each pixel was 15 μm, and the width of the partition wall dividing the adjacent 2 pixels was 6 μm. The size and the like of each pixel are designed in consideration of the light emission characteristics and the like of the display panel. Therefore, the above numerical values are representative values and are not necessarily limited to the above numerical values.

Fig. 1B shows a case where droplets of ink 40Y are caused to flow out to a region (pixel) surrounded by the partition wall 24Y when the light-emitting layer 21Y is formed by an ink-jet method.

Hereinafter, for example, a case where the ink 40Y is applied to the region surrounded by the partition wall 24Y using an inkjet head capable of discharging the ink 40Y having a droplet volume of 1 picoliter (pL) is considered.

The diameter of the droplet of the ink 40 having a volume of 1pL was 12.6. mu.m. On the other hand, the width of the region to which the ink 40Y is to be applied is 15 μm as described above. That is, the width of the region to which the ink 40Y is applied and the size of the droplet of the ink 40Y are almost equal. Therefore, extremely high accuracy is required for the landing position accuracy of the ink 40Y applied to the pixel. That is, it is practically difficult to form a coating film stably without color mixing. Therefore, the yield at the time of device manufacturing is lowered. This may increase the cost of the display panel, or reduce the light emission characteristics due to color mixing.

Disclosure of Invention

In the present disclosure, even when the interval between the regions surrounded by the partition walls is narrowed, a functional film such as a light emitting layer can be efficiently formed by an ink jet method. Thus, a color conversion device, a micro LED display panel, and the like can be provided which can achieve both suppression of reduction in light emission characteristics and reduction in cost.

One embodiment of a color conversion device according to the present disclosure includes: a substrate; a light emitting layer located over the substrate and including a light emitting material; a first partition wall which is in contact with the light-emitting layer and defines a light-emitting region where the light-emitting layer emits light; and a second partition wall which is in contact with the light-emitting layer and defines a formation region where the light-emitting layer is formed. Further, the contact area of the light emitting layer with the first partition wall is larger than the contact area of the light emitting layer with the second partition wall.

One embodiment of the micro LED display panel according to the present disclosure includes a color conversion device and a light emitting device that emits light incident on the color conversion device.

In addition, one embodiment of a method for manufacturing a color conversion device according to the present disclosure includes: the first step is to form a first partition wall on a substrate, the first partition wall defining a light-emitting region where a light-emitting layer emits light. Further comprising: a second step of forming a second partition wall defining a formation region for forming a light-emitting layer on the substrate; and a third step of applying ink containing a light-emitting material to a region surrounded by the second partition wall to form a light-emitting layer. In the first step and the second step, the first partition wall and the second partition wall are formed such that a first distance from the substrate to a top of the first partition wall is shorter than a second distance from the substrate to a top of the second partition wall.

In addition, one mode of the method for manufacturing a micro LED display panel according to the present disclosure is a method for manufacturing a micro LED display panel using a color conversion device manufactured by the method for manufacturing a color conversion device, including a step of bonding a color conversion device and a light emitting device that emits light incident on the color conversion device.

According to the present disclosure, even when the interval between the regions surrounded by the partition walls is narrowed, a functional film such as a light emitting layer can be efficiently formed by an ink jet method. Therefore, it is possible to provide a color conversion device, a micro LED display panel, and the like, which can achieve both suppression of reduction in light emission characteristics and reduction in cost.

Drawings

Fig. 1A is a plan view showing an example of a structure of a device used for a display panel having a pixel resolution of 400 ppi.

Fig. 1B is a cross-sectional view showing a state when ink is caused to flow out to the pixels of the apparatus shown in fig. 1A.

Fig. 2 is a cross-sectional view of the micro LED display panel according to the embodiment.

Fig. 3A is a top view of the color conversion apparatus according to the embodiment.

Fig. 3B is a cross-sectional view of the color changing device at line 3B-3B of fig. 3A.

Fig. 4 is a sectional view showing another configuration of the color conversion device according to the embodiment.

Fig. 5A is a diagram illustrating a substrate preparation step in the method of manufacturing a color conversion device according to the embodiment.

Fig. 5B is a diagram illustrating a first partition wall forming step in the method of manufacturing a color conversion device according to the embodiment.

Fig. 5C is a diagram illustrating a second partition wall forming step in the method of manufacturing a color conversion device according to the embodiment.

Fig. 5D is a diagram illustrating a light-emitting layer formation step in the method for manufacturing a color conversion device according to the embodiment.

Fig. 6A is a diagram illustrating a partition material application step in another method for manufacturing the first partition and the second partition in the color conversion device according to the embodiment.

Fig. 6B is a diagram illustrating an exposure step in another method for manufacturing the first partition wall and the second partition wall in the color conversion device according to the embodiment.

Fig. 6C is a diagram illustrating an etching step in another method for manufacturing the first partition wall and the second partition wall in the color conversion device according to the embodiment.

Fig. 7A is a plan view showing another configuration of the color conversion device according to the embodiment.

Fig. 7B is a cross-sectional view of the color changing device at line 7B-7B of fig. 7A.

Fig. 8A is a top view of the color conversion apparatus in the comparative example.

Fig. 8B is a cross-sectional view of the color conversion apparatus of the comparative example at the line 8B-8B of fig. 8A.

Fig. 9 is a sectional view of a color conversion apparatus according to modification 1.

Fig. 10A is a diagram showing a state immediately before ink application in the ink application step in the method of manufacturing a color conversion device according to modification 2.

Fig. 10B is a diagram showing a state immediately after ink application in the ink application step in the method of manufacturing a color conversion device according to modification 2.

Fig. 10C is a diagram showing a final state in the ink application step in the method of manufacturing a color conversion device according to modification 2.

Fig. 11A is a top view of a color conversion apparatus according to modification 3.

Fig. 11B is a sectional view of the color conversion device according to modification 3 at the line 11B-11B of fig. 11A.

Fig. 11C is a sectional view of the color conversion device according to modification 3 at the line 11C-11C of fig. 11A.

Fig. 12 is a plan view showing another configuration of the color conversion device according to modification 3.

Fig. 13 is a sectional view of the apparatus disclosed in patent document 1.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The embodiments described below are all specific examples of the present disclosure. Accordingly, the numerical values, the components, the arrangement positions and the connection modes of the components, the steps, the order of the steps, and the like shown in the following embodiments are examples, and the present disclosure is not limited thereto. Therefore, among the components in the following embodiments, components that are not recited in the independent claims may be described as arbitrary components.

Each drawing is a schematic diagram, and is not necessarily strictly illustrated. In the drawings, substantially the same components are denoted by the same reference numerals, and redundant description is omitted or simplified.

(embodiment mode)

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

< micro LED display Panel >

First, the structure of the micro led (light Emitting diode) display panel 1 according to the embodiment will be described with reference to fig. 2.

Fig. 2 is a cross-sectional view of the micro LED display panel 1 according to the embodiment. The micro LED display panel 1 is a display in which micro LEDs having a micron size are used as pixels (pixels).

As shown in fig. 2, the micro LED display panel 1 of the present embodiment has a light emitting device 10, a color conversion device 20 disposed opposite to the light emitting device 10, and the like.

In addition, the light emitting device 10 and the color conversion device 20 are fabricated by different steps and bonded to fabricate the micro LED display panel 1, and a specific fabrication method will be described later.

Also, the bonding portion of the light emitting device 10 and the color conversion device 20 is covered by a sealing material. This can prevent moisture, oxygen, and the like from entering the micro LED display panel 1 from the outside. As a result, the micro LED display panel 1 can be prevented from deteriorating, and the micro LED display panel 1 with high reliability can be realized.

The light emitting device 10 emits light incident to the color conversion device 20. The light emitting device 10 of the present embodiment is a blue light emitting device that emits light of blue color. Specifically, the light emitting device 10 is, for example, an LED device constituted by LEDs. The light-emitting device 10 may be an organic EL device or the like composed of organic EL (electro luminescence), or may be an inorganic EL device that emits light from an inorganic material.

As shown in fig. 2, the light-emitting device 10 of the present embodiment includes a substrate 12, a light-emitting body 11 disposed on the substrate 12, and the like.

< light-emitting body 11>

A plurality of light emitters 11 are arranged on the substrate 12. The light emitting body 11 is provided for each pixel of the micro LED display panel 1. That is, one light emitter 11 is provided corresponding to one pixel in the micro LED display panel 1.

The light emitting body 11 is a light source that emits light. The light emitter 11 of the present embodiment is a blue light emitter that emits blue light. In this case, from the viewpoint of cost and the like, it is preferable to use a blue LED as the light emitter 11, but the present invention is not limited thereto. For example, an organic EL device may also be used as the light-emitting device 10. In this case, the light emitter 11 is an organic EL light emitter composed of an organic EL film.

< substrate 12>

If the substrate 12 is made of an insulating material, any substrate can be used. Specifically, as the substrate 12, for example, a resin substrate made of an insulating resin material or a metal base substrate such as an aluminum alloy substrate having an insulating coating film on the surface thereof can be used. Further, as the substrate 12, for example, a ceramic substrate made of a ceramic material, a glass substrate made of a glass material, or the like can be used.

The substrate 12 may be a translucent substrate having translucency, or may be an opaque substrate that does not transmit light, depending on the direction in which light emitted from the light-emitting body 11 is extracted. When a translucent substrate is used, the substrate 12 is a transparent substrate such as a transparent resin substrate or a glass substrate. Further, the substrate 12 may be a rigid substrate or a flexible substrate.

The substrate 12 may also include a white insulating film such as a white resist formed on the surface of the substrate 12. This can improve the dielectric breakdown voltage of the substrate 12 and the light extraction efficiency.

< light emitting apparatus 10>

The light emitting apparatus 10 of the present embodiment has a partition wall 13. The partition wall 13 is made of, for example, a black or white resin material.

The partition walls 13 are provided so as to surround the respective luminous bodies 11. The partition wall 13 prevents light emitted from the light emitting body 11 from leaking to an adjacent pixel.

In addition, the light-emitting device 10 may also be provided with a driving transistor that controls light emission of the light-emitting body 11. In addition, for the blue LED used as the light emitter 11, blue LEDs manufactured in different steps may be mounted on the substrate 12. Further, the blue LED may be formed directly on the substrate 12. For example, when an organic EL device is used as the light emitting device 10, an organic EL film may be directly formed on the substrate 12 as the light emitter 11 by a vacuum vapor deposition method or an ink jet method.

< color conversion apparatus 20>

Next, the color conversion device 20 will be described with reference to fig. 2 and with reference to fig. 3A and 3B.

Fig. 3A is a top view of the color conversion device 20 according to the embodiment. Fig. 3B is a cross-sectional view of the color changing device 20 at line 3B-3B of fig. 3A.

The color conversion device 20 has, for example, a function of converting light incident from the light emitting device 10 to the color conversion device 20 into a wavelength of a given color. The color conversion device 20 has a plurality of light emitting layers 21, and functions as a wavelength conversion layer. Specifically, the light emitting layer 21 of the color conversion device 20 constitutes a wavelength conversion layer that converts the wavelength of light emitted from the light emitting device 10 into a wavelength of a color different from the color of light emitted from the light emitting device 10.

The color conversion device 20 of the present embodiment has a red light-emitting layer 21r, a green light-emitting layer 21g, and a blue light-emitting layer 21b as the light-emitting layers 21. The red light-emitting layer 21r has a function of converting the wavelength of blue light emitted from the light-emitting device 10 into a wavelength of red. The green light-emitting layer 21g has a function of converting the wavelength of blue light emitted from the light-emitting device 10 into the wavelength of green. The blue light emitting layer 21b has a function of transmitting blue light emitted from the light emitting device 10 as it is.

< light-emitting layer 21>

The plurality of luminescent layers 21 of the color conversion device 20 are arranged in correspondence with the plurality of luminous bodies 11 of the light emitting device 10. Specifically, the plurality of light emitting layers 21 are disposed to face the plurality of light emitters 11, respectively. More specifically, the red light-emitting layer 21r, the green light-emitting layer 21g, and the blue light-emitting layer 21b are provided in a one-to-one correspondence relationship with the plurality of light-emitting bodies 11, respectively, so as to face each other. That is, the plurality of light emitting layers 21 are provided corresponding to one pixel in the micro LED display panel 1, respectively.

The red light-emitting layer 21r corresponding to the red pixel and the green light-emitting layer 21g corresponding to the green pixel of the present embodiment are configured to include quantum dot materials (light-emitting materials). Examples of quantum dot materials that can be used include cadmium-selenium-based or indium-phosphorus-based, copper-indium-sulfur-based, silver-indium-sulfur-based, and perovskite-structured materials.

The red light-emitting layer 21r and the green light-emitting layer 21g are formed of, for example, a resin film in which a quantum dot material is dispersed. The concentration of the quantum dot material in the red light-emitting layer 21r and the green light-emitting layer 21g is preferably in the range of 5 weight percent or more and 50 weight percent or less.

Further, the red light-emitting layer 21r contains a quantum dot material that emits red light. The quantum dot material contained in the red light-emitting layer 21r of the present embodiment is excited by light of a blue wavelength emitted from the light-emitting device 10 to emit red light. That is, if light of a blue wavelength is irradiated to the red light-emitting layer 21r, the light of the blue wavelength is converted into a red wavelength. Thereby, red light is emitted from the red light-emitting layer 21 r.

Similarly, the green light emitting layer 21g includes a quantum dot material emitting green light. The quantum dot material included in the green light-emitting layer 21g of the present embodiment is excited by light of a blue wavelength emitted from the light-emitting device 10 to emit green light. That is, if light of a blue wavelength is irradiated to the green light-emitting layer 21g, the light of the blue wavelength is converted into a green wavelength. Thereby, green light is emitted from the green light-emitting layer 21 g.

The blue light-emitting layer 21b of the present embodiment is formed of a resin film containing no quantum dot material. Therefore, if light having a blue wavelength is irradiated to the blue light emitting layer 21b, blue light is emitted from the blue light emitting layer 21b as it is.

Here, the resin material constituting the red light emitting layer 21r, the green light emitting layer 21g, and the blue light emitting layer 21b is, for example, an acrylic resin or an epoxy resin. As the resin material constituting the red light-emitting layer 21r, the green light-emitting layer 21g, and the blue light-emitting layer 21b, an ultraviolet curable resin that is cured by irradiation of ultraviolet rays is preferably used.

Further, the light-emitting layer 21 may have diffusing particles (scattering particles) having a property of scattering light in the resin film. That is, the diffusion particles may be dispersed in the resin material constituting the red light-emitting layer 21r, the green light-emitting layer 21g, and the blue light-emitting layer 21 b. In this case, the blue light-emitting layer 21b of the present embodiment includes only the diffusion particles out of the quantum dot material and the diffusion particles.

In this case, for example, titanium oxide particles, zirconium oxide particles, or hollow silica particles having a hollow interior can be used as the diffusion particles. The particle diameter of the diffusion particles is, for example, in the range of 50nm to 1000 nm. Further, the light-emitting layers 21 each contain diffusion particles at a concentration of, for example, several weight percent. When the light-emitting layer 21 contains the diffusion particles, blue light entering the light-emitting layer 21 is scattered and the light path length for traveling is increased. This increases the number of times that blue light hits the quantum dot material having a wavelength conversion function in the light-emitting layer 21. As a result, the wavelength conversion efficiency of the light-emitting layer 21 is increased.

The light-emitting layer 21 may further contain particles that absorb moisture. This can suppress deterioration of the light-emitting layer 21 due to moisture absorption.

The color conversion device 20 further has a substrate 22, and the light emitting layer 21 is disposed on the substrate 22. Specifically, the light-emitting layer 21 is provided on the front surface which is one surface of the substrate 22.

< substrate 22>

Any material can be used if the substrate 22 is an insulating material. For example, a resin substrate, a metal base substrate, a ceramic substrate, a glass substrate, or the like can be used as the substrate 22.

The substrate 22 may be a translucent substrate having translucency or a non-translucent substrate not transmitting light in the light extraction direction. When a translucent substrate is used as the substrate 22, the substrate 22 is a transparent substrate such as a transparent resin substrate or a glass substrate. Further, the substrate 22 may be a rigid substrate or a flexible substrate.

In the present embodiment, a glass substrate is used as the substrate 22, for example. In this case, it is preferable that the substrate 22 is provided with a light-shielding film having a light-shielding property so that light emitted from the light-emitting layer 21 does not transmit through the substrate 22. Specifically, the light-shielding film may be formed of, for example, a light-reflecting film having light reflectivity on the front surface (surface on which the light-emitting layer 21 is provided) of the substrate 22. The light reflecting film may be formed of a white film such as a white resist formed of a white insulating resin material or the like. Alternatively, a metal film having light reflectivity may be formed as a light reflective film on the back surface of the substrate 22. Specifically, a metal film made of a silver-palladium-copper alloy or the like may be formed on the back surface of the substrate 22.

Further, the color conversion device 20 of the present embodiment has a first partition wall 23 and a second partition wall 24. The first partition wall 23 and the second partition wall 24 are also provided on the front surface which is one surface of the substrate 22, similarly to the light-emitting layer 21.

< partition wall >

The first partition wall 23 and the second partition wall 24 are provided so as to surround the light-emitting layer 21.

The first partition wall 23 defines a light emitting region where the light emitting layer 21 emits light. The second partition wall 24 defines a formation region where the light-emitting layer 21 is formed.

The light-emitting layer 21 of the present embodiment is formed by applying ink using an inkjet method. Therefore, the second partition wall 24 serves as an application region (ink application region) to which ink is applied.

The second partition wall 24 is formed in common with and integrally with the plurality of light-emitting layers 21. The second partition wall 24 has a plurality of openings formed corresponding to the plurality of light-emitting layers 21, respectively, as a region surrounded by the second partition wall 24. That is, the light-emitting layers 21 are formed in the plurality of openings formed by the second partition walls 24.

The first partition wall 23 is provided at each of the plurality of openings of the second partition wall 24. That is, a plurality of first partition walls 23 are provided corresponding to each of the plurality of light emitting layers 21. The shape of the opening portion formed (surrounded) by the second partition wall 24 is, for example, an elliptical shape (elliptic cylindrical shape) or a shape obtained by adding two crescent shapes (cylindrical bodies) opposed to a circular shape (cylindrical shape) as shown in fig. 3A. With this shape, the openings can be formed at a high density on the front surface of the substrate 22, and the distance between the openings can be maintained. This can prevent color mixing from occurring between the light-emitting layers 21. The region defined by the first partition wall 23 has a circular shape (cylindrical shape). This makes it possible to make the light emission from the light-emitting layer 21 uniform.

The first partition 23 is formed in a shape of, for example, a crescent pillar (columnar body) in 2 directions of the side surfaces facing the opening of the second partition 24 formed in the longitudinal direction (longitudinal direction) of the substrate 22. This can ensure the volume (volume) of the opening, and can make the space mainly forming the light-emitting layer 21 cylindrical. As a result, a uniform amount of light emitted from the light-emitting layer 21 can be ensured.

In each pixel, a region (opening) surrounded by the second partition wall 24 has a flat shape in a plan view, for example. Specifically, the region (opening) surrounded by the second partition wall 24 in the present embodiment has a racetrack-like oblong shape as shown in fig. 3A in a plan view. The region surrounded by the first partition wall 23 and located inside the second partition wall 24 is circular in plan view.

In each pixel, the first partition wall 23 is formed so as to be in contact with the inner wall surface of the second partition wall 24 as shown in fig. 2. That is, the region surrounded by the second partition wall 24 of the present embodiment includes only one region surrounded by the first partition wall 23. Further, in the region surrounded by the second partition wall 24, one light emitting layer 21 is provided.

Further, the film thickness of the first partition wall 23 is thinner than the film thickness of the second partition wall 24 in the present embodiment. That is, the height of the first partition wall 23 is lower than the height of the second partition wall 24. Specifically, a first distance from the substrate 22 to the top 23a of the first partition wall 23 is shorter than a second distance from the substrate 22 to the top 24a of the second partition wall 24. For example, the first distance (film thickness) of the first partition 23 is about 2 μm or more and 9 μm or less, and preferably 3 μm or more and 7 μm or less. On the other hand, the second distance (film thickness) of the second partition wall 24 is about 5 μm or more and 10 μm or less, and preferably 6 μm or more and 8 μm or less. That is, if the first partition wall 23 is too low, light emission of the light emitting layer disposed on the first partition wall 23 cannot be ignored. Therefore, the film thickness of the first partition wall 23 is preferably set to be as close as possible to the film thickness of the second partition wall 24.

Each light-emitting layer 21 is in contact with each of the corresponding first partition wall 23 and second partition wall 24. Specifically, in each of the red light-emitting layer 21r, the green light-emitting layer 21g, and the blue light-emitting layer 21b, the light-emitting layer 21 is formed in contact with each of the first partition wall 23 and the second partition wall 24. Thus, compared to a structure in which the light-emitting layer 21 is in contact with only one of the first partition wall 23 and the second partition wall 24, the contact area between the light-emitting layer 21 and the partition wall surrounding the light-emitting layer 21 (the first partition wall 23 and the second partition wall 24) can be increased. As a result, the adhesion between the light-emitting layer 21 and the partition wall is improved. In particular, in the case where the substrate 22 is a flexible substrate, the reliability of the color conversion device 20 against, for example, peeling or the like caused by deformation or the like is improved.

The first partition wall 23 is formed so as to surround the red light-emitting layer 21r, the green light-emitting layer 21g, and the blue light-emitting layer 21b at the openings of the corresponding second partition walls 24. Thus, the light-emitting layer 21 is in contact with the inner wall surface of the first partition wall 23 and the entire surface of the ceiling portion 23a in the region (opening) surrounded by the second partition wall 24, and also in contact with the inner wall surface of the upper portion of the second partition wall 24.

In the present embodiment, the first partition wall 23 is formed to have a film thickness smaller than that of the second partition wall 24. That is, the thickness of the light-emitting layer 21 located at the top 23a of the first partition wall 23 is thinner than the other portions. Therefore, the light-emitting layer 21 located at the top 23a of the first partition wall 23 hardly functions as a wavelength conversion layer and does not emit light. Further, even if light is emitted slightly, for example, the emitted light is shielded by the first partition wall 23. Therefore, light is not extracted to the outside of the light-emitting layer 21. This contributes to light emission only in the region defined by the inside of the first partition wall 23.

According to the configuration of the color conversion apparatus 20 described above, a formation area (ink application area) in which the light emitting layer 21 is formed can be widely secured. Further, a light emitting region where the light emitting layer 21 emits light can be defined to have a predetermined size. As a result, the light-emitting layer 21 serving as a functional film can be formed at high quality and low cost by the ink jet method.

Further, if the first partition wall 23 and the second partition wall 24 are made of insulating materials, they may be made of any one of inorganic materials and organic materials. For example, the first partition wall 23 and the second partition wall 24 are formed using a photosensitive resin cured by ultraviolet rays. In this case, the first partition wall 23 and the second partition wall 24 are preferably formed of the same resin material.

The first partition wall 23 defining the light-emitting region of the light-emitting layer 21 is preferably formed of a white material so as to efficiently extract light emitted from the light-emitting layer 21. For example, a white resist or the like can be used as the first partition wall 23.

On the other hand, the second partition walls 24 defining the formation region of the light-emitting layer 21 are preferably formed of a material having lower wettability than the first partition walls 23 and having liquid repellency to ink to be applied. Therefore, for example, a fluorine resin or the like containing a functional group containing a fluorine atom in a resin is used as the second partition wall 24 in order to provide liquid repellency. The fluororesin is not particularly limited as long as it is a fluororesin in which at least a part of the repeating units of the polymer of the fluororesin have fluorine atoms. Specifically, examples of the fluororesin include fluorinated polyolefin resins, fluorinated polyimide resins, fluorinated polypropylene resins, and the like.

As described above, the second partition walls 24 of the present embodiment have lower wettability than the first partition walls 23. That is, the first partition wall 23 is made of a material having higher wettability than the second partition wall 24. Therefore, in each light-emitting layer 21, the contact area between the light-emitting layer 21 and the first partition wall 23 is preferably larger than the contact area between the light-emitting layer 21 and the second partition wall 24. This improves the adhesion of the light-emitting layer 21 to the first partition wall 23.

< color Filter 25>

Hereinafter, another configuration of the color conversion device according to the embodiment will be described with reference to fig. 4.

Fig. 4 is a sectional view showing another configuration of the color conversion device according to the embodiment.

Another structure of the color conversion device is a structure in which a color filter 25 is further provided in each light-emitting layer 21.

That is, as shown in fig. 4, for example, a red color filter 25r is provided in the red light-emitting layer 21r, a green color filter 25g is provided in the green light-emitting layer 21g, and a blue color filter 25b is provided in the blue light-emitting layer 21 b.

By providing the color filter 25, only a desired wavelength can be transmitted, and thus the color reproducibility of the color conversion device can be improved. Specifically, the chromaticity of light emitted by the red light-emitting layer 21r, the green light-emitting layer 21g, and the blue light-emitting layer 21b is improved relative to blue light emitted by the light-emitting device 10 that emits blue light, and thus the color reproducibility is improved.

Further, the light emission efficiency of the light emitting layer 21 can be improved by providing the color filter 25.

The color conversion device does not necessarily need to be provided with the color filter 25, and may be appropriately provided according to the application and the like.

< method for manufacturing micro LED display Panel >

Next, a method for manufacturing the micro LED display panel 1 according to the embodiment will be described.

Specifically, the method of manufacturing the micro LED display panel 1 of the present embodiment includes a step of manufacturing the light emitting device 10, a step of manufacturing the color conversion device 20, and a step of bonding the color conversion device 20 and the light emitting device 10.

[ method for manufacturing light-emitting device ]

First, a method of manufacturing the light emitting device 10 is explained.

For example, the light emitting apparatus 10 first transfers the blue light-emitting emitters 11 fabricated by other steps onto the substrate 12. This makes it possible to obtain the light-emitting device 10 in which the light-emitting bodies 11 are arranged on the substrate 12. In this case, the partition wall 13 formed by photolithography or the like is provided on the substrate 12 so that light emitted from the light emitter 11 does not leak to an adjacent pixel. The partition wall 13 is disposed so as to surround each light emitter 11.

[ method of manufacturing color conversion device ]

Next, a method of manufacturing the color conversion device 20 will be described with reference to fig. 5A to 5D.

Fig. 5A to 5D are diagrams illustrating a manufacturing flow of the method of manufacturing the color conversion device 20 according to the embodiment. Fig. 5A, 5B, 5C, and 5D show a substrate preparation step, a first partition wall forming step (first step), a second partition wall forming step (second step), and a light-emitting layer forming step (third step), respectively.

In detail, as shown in fig. 5A, the substrate preparation step of the manufacturing method of the color conversion device 20 is a step of preparing the substrate 22 (substrate preparation step). As shown in fig. 5B, the first partition wall forming step is a step of forming a first partition wall 23 that defines a light-emitting region where the light-emitting layer 21 emits light on the substrate 22. As shown in fig. 5C, the second partition wall forming step is a step of forming the second partition wall 24 defining a formation region for forming the light-emitting layer 21 on the substrate 22. Further, as shown in fig. 5D, the light-emitting layer forming step is a step of forming the light-emitting layer 21 by applying ink containing a quantum dot material to the region surrounded by the second partition wall 24.

In addition, the color conversion device 20 of the present embodiment forms the first partition wall 23 and the second partition wall 24 in the first partition wall forming step and the second partition wall forming step such that a first distance from the substrate 22 to the top 23a (refer to fig. 2) of the first partition wall 23 is shorter than a second distance from the substrate 22 to the top 24a (refer to fig. 2) of the second partition wall 24.

Specific examples of the steps of the first partition wall forming step, the second partition wall forming step, and the light-emitting layer forming step will be described below.

(substrate preparation step)

In the substrate preparation step, as shown in fig. 5A, the substrate 22 is prepared. In the present embodiment, a glass substrate is prepared as the substrate 22.

(first partition wall formation step)

In the first partition wall forming step, the first partition wall 23 is formed on the substrate 22. The first partition wall 23 is formed by, for example, a photolithography process using a photosensitive resin.

Specifically, first, a photosensitive resin, which is a negative material cured by exposure to ultraviolet light, is applied to the substrate 22 by an application method such as a spin coating method or a slit coating method. Thereby, a coating film of a photosensitive resin is formed on the substrate 22. At this time, the coating condition of the photosensitive resin is adjusted by the number of revolutions of spin coating, the scanning speed of slit coating, or the like according to the required film thickness.

Next, the coated film is prebaked using a hot plate or the like to dry the solvent component. Thereafter, the coating film is exposed to ultraviolet light through a photomask having a desired pattern formed thereon. The photosensitive resin includes a negative material that is cured by an exposed portion irradiated with the ultraviolet ray and a positive material that is cured by an unexposed portion irradiated with the ultraviolet ray, and any of these materials can be used.

Next, the coating film on the uncured portion is removed using an appropriate developing solution according to the type of the material of the photosensitive resin used. Thereafter, the remaining pattern of the coating film is post-baked by a curing oven or the like. As a result, as shown in fig. 5B, the first partition wall 23 having a predetermined shape is formed on the substrate 22.

More specifically, in the present embodiment, as described above, a photosensitive white resin having a high reflectance is used as the material of the first partition walls 23. As the photosensitive white resin, a photosensitive resin obtained by adding an inorganic substance such as white titanium oxide particles to an acrylic resin or an epoxy resin can be used.

The substrate 22 was coated with a white resin by a slit coating method, heated at 80 ℃ for 30 minutes by a hot plate, and pre-baked.

Next, ultraviolet rays having a wavelength of 365nm were irradiated to cure the white resin. At this time, the exposure amount of the ultraviolet ray was set to 500mJ/cm²。

Next, the white resin is developed with a developer. Specifically, 1 wt% of Na was used₂CO₃The white resin was developed by spray coating for 60 seconds as a developing solution.

Thereafter, the white resin was post-baked at 150 ℃ for 60 minutes using a curing oven. Thereby, the first partition walls 23 made of white resin having a film thickness of 5 μm were formed.

In the above embodiment, the first partition wall 23 is described using a white resin as an example, but the present invention is not limited thereto. For example, a yellow resin may be used to improve the weather resistance. The first partition 23 may be made of a 2-layer resin. Specifically, the first barrier ribs 23 are formed of 2 layers each having black color below the first barrier ribs 23 and white color above the first barrier ribs 23. This can improve the contrast of the emission color in the light-emitting layer 21.

(second partition wall Forming step)

In the second partition wall forming step, the second partition wall 24 is formed outside the first partition wall 23.

Specifically, similarly to the first partition walls 23, the second partition walls 24 are formed outside the first partition walls 23 by a photolithography process using a photosensitive resin, as shown in fig. 5C. At this time, the second partition walls 24 are formed so that the film thickness of the second partition walls 24 is larger than the film thickness of the first partition walls 23. Thus, as described above, the region surrounded by the second partition wall 24 is formed in a flat shape in a plan view (see fig. 3A).

In the present embodiment, a fluorine-containing acryl resin containing fluorine is used as a material of the second partition wall 24. Specifically, as the fluorine-containing acryl resin, a material having a feature that fluorine spreads over the surface by exposure is used. This provides liquid repellency to the surface of second partition wall 24.

Here, a contact angle for evaluating liquid repellency will be described.

Generally, if a liquid drops on a solid surface, the liquid is rounded by its own surface tension. At this time, the relationship shown in (equation 1) called Young equation holds.

γ_s＝γ_L×cosθ+γ_sLDEG- (formula 1)

γ_s: surface tension of solids, gamma_L: surface tension of liquid, gamma_sL: interfacial tension of solid and liquid.

At this time, the angle θ formed by the tangent of the liquid droplet and the solid surface is referred to as a contact angle. Among the contact angles, a contact angle at which a liquid comes to rest on a solid to reach an equilibrium state is referred to as a stationary contact angle. On the other hand, the contact angles in the state of the interfacial motion between the liquid and the solid, that is, in the dynamic state of the interfacial motion of the liquid droplet are referred to as an advancing contact angle and a receding contact angle.

Specifically, the stationary contact angle of the second partition wall 24 of the present embodiment with respect to the ink is about 50 °.

As described above, the first partition wall 23 of the present embodiment is formed so that the film thickness is set to 5 μm. The second partition wall 24 is formed to have a film thickness set to 8 μm so that the second partition wall 24 is thicker than the first partition wall 23.

In the above-described embodiment, the description has been made by taking an example in which the second partition wall forming step is performed after the first partition wall forming step, but the present invention is not limited to this. For example, the first partition wall forming step and the second partition wall forming step may be replaced with each other, and the second partition wall forming step may be performed first. That is, the first partition wall forming step may be performed after the second partition wall forming step.

In the above embodiment, the first partition wall 23 and the second partition wall 24 are produced by different steps, but the present invention is not limited to this. For example, the first partition wall 23 and the second partition wall 24 may be formed simultaneously in one step by halftone exposure in which the transmittance varies depending on the place, using the same photosensitive resin material.

Next, another method for manufacturing the first partition wall 23 and the second partition wall 24 by halftone exposure will be described with reference to fig. 6A to 6C.

Fig. 6A is a diagram illustrating a partition material application step in another manufacturing method of the first partition 23 and the second partition 24 in the color conversion device according to the embodiment. Fig. 6B is a diagram illustrating an exposure step in another manufacturing method of the first partition wall 23 and the second partition wall 24. Fig. 6C is a diagram illustrating an etching step in another manufacturing method of the first partition wall 23 and the second partition wall 24.

In another manufacturing method of the first partition wall 23 and the second partition wall 24, first, as shown in fig. 6A, a partition wall material 30 is formed on the substrate 22 by using a spin coating method or a slit coating method. In this case, a photosensitive resin material made of a negative material similar to the first partition wall 23 or the second partition wall 24 can be used as the partition wall material 30.

Next, as shown in fig. 6B, ultraviolet rays are irradiated to the partition wall material 30 through the photomask 100. Thereby, the partition wall material 30 is exposed to light and cured. At this time, the transmittance of the ultraviolet ray of the photomask 100 is locally changed. That is, the degree of curing of the partition wall material 30 is changed by changing the transmittance of ultraviolet rays. Specifically, the photomask 100 is provided with a shielding portion 101 for shielding ultraviolet rays, and a first opening 102 and a second opening 103 having different transmittances. At this time, the transmittance of the second opening 103 is made higher than the transmittance of the first opening 102. This changes the amount of ultraviolet light transmitted through the first opening 102 and the second opening 103 of the transmitted light mask 100.

Next, as shown in fig. 6C, the uncured portions of the partition wall material 30 are etched with a developing solution. In this case, the portion where the transmission amount of ultraviolet rays is small is cured to a small extent. Therefore, the thickness of the partition wall material 30 after etching is made thin.

As described above, the first partition wall 23 and the second partition wall 24 having different thicknesses can be simultaneously formed by etching using halftone exposure.

In the above-described manufacturing method, a method of using a negative type material in which a portion irradiated with ultraviolet rays is cured has been described as an example, but a positive type material in which a portion irradiated with ultraviolet rays is dissolved may be used. In this case, the relationship of the transmittance of the photomask 100 is different. That is, the shielding portion 101 of the photomask 100 is a first opening portion, and the second opening portion 103 is a shielding portion. The transmittance of the first opening portion may be higher than the transmittance of the second opening portion. Thus, even if a positive material is used, the first partition wall 23 and the second partition wall 24 having different thicknesses can be simultaneously formed in one step.

(light-emitting layer Forming step)

In the light-emitting layer forming step, first, ink is applied to the substrate 22 on which the first barrier ribs 23 and the second barrier ribs 24 are formed by an ink jet method to form a coating film.

In the present embodiment, in the formation of the red light-emitting layer 21r and the green light-emitting layer 21g, ink in which a quantum dot material is dispersed at a predetermined concentration is discharged into the region surrounded by the second partition wall 24 by an ink jet method. On the other hand, in the formation of the blue light emitting layer 21b, ink not containing a quantum dot material is discharged into the region surrounded by the second partition wall 24 by an ink jet method.

In addition, when forming the coating films constituting the red light emitting layer 21r, the green light emitting layer 21g, and the blue light emitting layer 21b, the amount of ink flowing out from the nozzle of the inkjet head is determined so that the film thickness after the flowing-out ink is dried and cured becomes a predetermined film thickness.

In this embodiment, as the ink, an ink in which a cadmium-selenium-based quantum dot material is dispersed in an acrylic resin is used. The quantum dot material has a particle diameter of 20nm to 30 nm. In addition, in order to scatter blue light, the optical path length in the light-emitting layer 21 is contrived, and titanium oxide particles are contained as diffusion particles in the ink. Specifically, titanium oxide particles having a particle diameter of about 100nm or more and 1000nm or less are used. The ink having the above-described structure is applied to the region surrounded by the second partition wall 24 by an ink jet method.

In the present embodiment, the direction of application of the same color ink is perpendicular to the longitudinal direction of the region surrounded by the second partition walls 24, as shown in fig. 3A. That is, the printing direction of the same ink is perpendicular to the long axis direction in which the pixels of R, G, B are arranged in order. The nozzles of the ink jet head to which the ink is applied are provided for each of the red light-emitting layer 21r, the blue light-emitting layer 21b, and the green light-emitting layer 21 g. The arrangement direction of the nozzles of the inkjet head is the same as the longitudinal direction of the region surrounded by the second partition wall 24. Thus, even if the interval between the regions surrounded by the second partition walls 24 is narrowed and the pixel array pattern has high resolution, ink can be easily applied without causing color mixture.

This point will be explained below.

In general, the timing of ink discharge is adjusted with respect to the direction of application (printing direction) of ink, so that ink can be landed on a predetermined position relatively easily. On the other hand, the alignment direction of the nozzles of the inkjet head depends on the processing accuracy of the nozzles, and therefore, it is difficult to correct the landing positions of the ink.

Therefore, in the present embodiment, the arrangement direction of the nozzles of the inkjet head is made the same as the longitudinal direction of the region surrounded by the second partition wall 24. This makes it possible to enlarge the landing area of ink with respect to the direction in which the nozzles are arranged, and to increase the allowable swing width of the landing position of ink. Specifically, the area surrounded by the second partition wall 24 as the application area for applying ink can be enlarged with respect to the area surrounded by the first partition wall 23 (the light emitting area where the light emitting layer 21 emits light). Thus, even in a high-resolution pixel array pattern, ink can be easily applied to a region at a predetermined position without causing color mixing.

Next, the substrate 22 on which the coating film is formed by the application of the ink is dried. In this case, a solvent having a high boiling point is often used for the ink discharged by the ink jet method in order to suppress drying of the solvent at the nozzle. Therefore, it is preferable to use reduced pressure drying for drying the ink. In the case of performing the reduced pressure drying, for example, the substrate 22 coated with the ink is placed in a drying oven, and the inside of the drying oven is reduced in pressure by a vacuum pump to reduce the pressure. Thereby, evaporation of the solvent is promoted. In this case, the degree of vacuum reached in the drying furnace is several Pa, and the holding time is about several tens minutes. The conditions for achieving the degree of vacuum and the retention time are not limited to the above conditions, since the conditions vary depending on the boiling point of the solvent contained in the ink.

In addition, when the ink which flows out does not contain a solvent and an ink in which a quantum dot material is dispersed only in an ultraviolet curable resin is used, drying such as drying under reduced pressure may not be performed.

Next, prebaking of the coating film was performed using a hot plate at 100 ℃ for about 5 minutes.

Then, the coating film was cured by irradiating ultraviolet rays having a wavelength of 365nm thereto. In this case, the dose of ultraviolet light is, for example, 200mJ/cm²Above and 1000mJ/cm²The following.

Next, post baking of the coating film was performed at 150 ℃ for about 20 minutes using a curing oven. Thereby, as shown in fig. 5D, the light-emitting layers 21 are formed in the regions (openings) surrounded by the second partition walls 24.

Specifically, in the present embodiment, pre-baking (100 ℃ C., 5 minutes), irradiation of ultraviolet rays (wavelength: 365nm, exposure amount: 300 mJ/cm) and the like are sequentially performed²) And post-baking (150 ℃ C., 20 minutes) to cure the coating film applied to the substrate 22.

From the above, as shown in fig. 3A and 3B, the color conversion device 20 in which the plurality of light emitting layers 21 are arranged at a given pitch is fabricated on the substrate 22.

In the present embodiment, as shown in fig. 3A and 3B, an example in which the arrangement direction of the light-emitting layers 21 of the same color is aligned in a direction perpendicular to the longitudinal direction of the region surrounded by the second partition walls 24 is described, but the present invention is not limited to this. For example, as described below with reference to fig. 7A and 7B, the arrangement direction of the light-emitting layers 21 of the same color may be arranged so as to intersect (be inclined) in a direction perpendicular to the longitudinal direction of the region surrounded by the second partition walls 24. In this case, the inclination angle is preferably 30 to 60 degrees, more preferably 40 to 50 degrees, with respect to the edge (longitudinal direction) of the substrate 22.

Fig. 7A is a plan view showing another configuration of the color conversion device according to the embodiment. Fig. 7B is a cross-sectional view of the color changing device at line 7B-7B of fig. 7A.

With the configuration shown in fig. 7A and 7B, the interval between the regions surrounded by the second partition walls 24 (the interval in the longitudinal direction) can be narrowed. This can further increase the number of light-emitting layers 21. That is, a higher resolution color conversion apparatus can be easily realized.

(action Effect and the like)

Next, the operation and effect of the color conversion device 20 according to the present embodiment will be described in comparison with the color conversion device 20Z of the comparative example shown in fig. 8A and 8B.

Fig. 8A is a top view of the color conversion apparatus 20Z of the comparative example. Fig. 8B is a sectional view of the color conversion device 20Z of the comparative example at the line 8B-8B of fig. 8A.

As shown in fig. 8A and 8B, the color conversion device 20Z of the comparative example is configured, with respect to the color conversion device 20 of the present embodiment, such that the first partition wall 23, which is the first partition wall 23 defining the emission region and the second partition wall 24 defining the ink application region, is not provided. That is, in the color conversion apparatus 20Z of the comparative example, only the second partition wall 24 out of the first partition wall 23 and the second partition wall 24 exists.

In the case of this structure, the light emitting region of the light emitting layer 21 of the color conversion device 20Z of the comparative example is larger than that of the color conversion device 20 of the present embodiment shown in fig. 3A and 7A. That is, the size of the pixel to be a pixel becomes large.

Therefore, in the color conversion device 20Z of the comparative example, if the distance between pixels is too short, mutual interference between luminescent colors can be caused. In this case, it can be considered that in the color conversion device 20Z of the comparative example, the distance between pixels has to be pulled apart to design. Thus, in the display using the color conversion device 20Z of the comparative example, since the resolution becomes low, it is difficult to realize high-definition image quality.

In contrast, the color conversion device 20 of the present embodiment forms the second partition wall 24 defining the ink application region and the first partition wall 23 defining the light emission region. Specifically, the first partition wall 23 is formed inside the region surrounded by the second partition wall 24.

With this structure, with the color conversion device 20 of the present embodiment, even if the range of the ink application region is the same as the color conversion device 20Z of the comparative example, the light emission region where the light emitting layer 21 emits light can be reduced. Thereby, it is possible to substantially reduce the size of the pixel and improve the resolution as compared with the color conversion device 20Z of the comparative example. In other words, as in the present embodiment, even with the color conversion device 20 having pixels arranged at high resolution, the light emitting layer 21 can be easily formed without color mixing by the ink jet method.

As described above, according to the color conversion device 20 and the micro LED display panel 1 of the present embodiment, even if the interval between the regions (openings) surrounded by the second partition wall 24 is designed to be narrow, the light emitting layer 21 can be easily formed using the ink jet method. That is, the ink can be stably applied to the opening without mixing the color. As a result, the color conversion device 20 and the micro LED display panel 1 including the color conversion device 20 can be realized while suppressing the reduction in light emission characteristics and reducing the cost.

(modification 1)

Next, a color conversion device 20A according to modification 1 of the present embodiment will be described with reference to fig. 9.

Fig. 9 is a sectional view of a color conversion device 20A according to modification 1.

As shown in fig. 9, the color conversion device 20A according to modification 1 is different from the color conversion device 20 of the above-described embodiment in that a light-emitting body 26 is provided on a substrate 22. Therefore, a micro LED display panel can be constituted only by the color conversion device 20A of modification 1.

Specifically, the light emitter 26 is a blue light emitter that emits blue light such as a blue LED. The light emitter 26 as a blue LED is formed by being mounted on the substrate 22. Otherwise, the configuration is the same as that of the color conversion device 20 of the above embodiment.

That is, according to the color conversion device 20A according to the modification 1, the light emitter 26 is incorporated in the color conversion device 20A. Therefore, the function of the light emitting device can be given to the color conversion device 20A. Thereby, the micro LED display panel can be realized only by the color conversion device 20A without bonding the light emitting device 10 of the embodiment to the color conversion device 20A. That is, the color conversion device 20A can be directly used as a micro LED display. As a result, the micro LED display panel can be made thinner.

(modification 2)

Next, a color conversion device 20B according to modification 2 of the present embodiment will be described with reference to fig. 10A to 10C.

Fig. 10A to 10C are diagrams illustrating a method of manufacturing a color conversion device 20B according to modification 2.

The color conversion device 20B according to modification 2 is different from the color conversion device 20 of the above embodiment in that the wettability of the top 23Ba of the first partition wall 23B is reduced.

Specifically, in each light-emitting layer 21, the stationary contact angle of the top portion 23Ba of the first partition wall 23B with respect to the ink 40 is equal to or larger than the stationary contact angle of the inner wall surface 23Bb (side surface) of the first partition wall 23 with respect to the ink 40.

In addition, in the second bank walls 24B, in each of the light emitting layers 21, the stationary contact angle of the top portions 24Ba of the second bank walls 24B with respect to the ink 40 is made larger than the stationary contact angle of the inner wall surfaces 24Bb (side surfaces) of the second bank walls 24B with respect to the ink 40.

In fig. 10A and 10B, the red ink 40r represents an ink for forming the red light-emitting layer 21r, and the green ink 40g represents an ink for forming the green light-emitting layer 21 g.

Here, in modification 2, the stationary contact angle of the top portion 23Ba of the first bank wall 23B with respect to the ink 40 is C1, the stationary contact angle of the inner wall surface 23Bb of the first bank wall 23B with respect to the ink 40 is C2, the stationary contact angle of the top portion 24Ba of the second bank wall 24B with respect to the ink 40 is C3, and the stationary contact angle of the inner wall surface 24Bb of the second bank wall 24B with respect to the ink 40 is C4. At this time, the color conversion device 20A of modification 2 is configured such that C1 to C4 satisfy the relational expression of C3 > C1 ≧ C2 ≧ C4.

For example, the static contact angles C1 and C3 are 40 ° or more and 70 ° or less. On the other hand, the static contact angles C2 and C4 are 5 ° or more and 40 ° or less.

As the material of the first partition wall 23B and the second partition wall 24B satisfying the above relational expression, a resin material is used which is configured such that a portion irradiated with ultraviolet rays is cured and a fluorine component in the resin is segregated on the surface of the film. Thereby, the first partition wall 23B and the second partition wall 24B having the stationary contact angles of the top portions 23Ba and 24Ba larger than the stationary contact angles of the inner wall surfaces 23Bb and 24Bb can be formed. In addition, the structure other than the first partition wall 23B and the second partition wall 24B is the same as that of the color conversion device 20 of the above embodiment.

First, a material for forming the partition wall uniformly contains fluorine in a liquid state. In this state, a material is coated and exposed to form the partition walls. Thereby, the polymerization reaction is started from the material of the exposed portion. Thereafter, it is completely cured by baking. At this time, the fluorine component in the film segregates upward. As a result, the partition walls are formed in a state where the surfaces of the formed partition walls contain a large amount of fluorine.

The static contact angles of the top portions 23Ba of the first partition walls 23B and the top portions 24Ba of the second partition walls 24B can be arbitrarily adjusted by using the above-described material in which the static contact angle varies depending on the film thickness of the partition walls. That is, the stationary contact angle of the fluororesin to be used changes because the fluorine content changes depending on the film thickness.

Further, it is also possible to form the first partition wall 23B and the second partition wall 24B using different materials, respectively, and change the stationary contact angle.

According to the above, the wettability of the top 23Ba of the first partition wall 23B of the color conversion device 20B of modification 2 becomes low.

Specifically, as shown in fig. 10A, the ink 40 is applied by an ink jet method to the region surrounded by the second partition wall 24B.

As shown in fig. 10B, the ink 40 immediately after application exists so that the ink also covers the top portions 23Ba of the first partition walls 23B. At this time, as described above, the stationary contact angle of the top portion 23Ba of the first partition wall 23B with respect to the ink 40 is larger than the stationary contact angle of the inner wall surface 23Bb of the first partition wall 23B with respect to the ink 40. Therefore, the ink 40 present on the top portion 23Ba of the first partition wall 23B slides down along the inner wall surface 23Bb of the first partition wall 23B.

Finally, as shown in fig. 10C, the ink 40 is received in the region surrounded by the first partition wall 23B.

The wettability of the top 24Ba of the second partition wall 24B is defined by a receding contact angle in addition to the above-described static contact angle. The receding contact angle is a contact angle in a state of interfacial motion between a liquid and a solid, that is, a dynamic state of interfacial motion of ink.

In this case, if the receding contact angle is small, the ink adhering to the second partition walls 24B tends to be wet and remain when it shrinks during drying or curing. Therefore, ink may remain on the second partition wall 24B. In this case, the second partition wall 24B is formed such that the receding contact angle of the second partition wall 24B with respect to the ink is 15 ° or more, preferably 20 ° or more. This can more reliably prevent the ink from wetting and remaining on the second partition walls 24B, as described below.

(comparison of ink wetting due to difference in receding contact Angle)

The results of comparing the wettability of the ink due to the difference in receding contact angle are shown below in table 1.

Table 1 shows the static contact angle and receding contact angle of ink when the material type of the partition wall was changed, and the wettability of ink on the partition wall.

[ Table 1]

	Static contact angle	Receding contact angle	Wetting of ink on partition walls
				Ink A	64.6°	39.3°	No wetting residue
Ink B	42.6°	18.9°	No wetting residue
				Ink C	48.0°	12.2°	Has wetting residue
Ink D	45.9°	9.6°	Has wetting residue

The receding contact angle is determined by the balance of the surface energies of the material composition of the ink and the material composition of the partition walls.

Specifically, the ink a is an ink in which a polymer-based light-emitting material is dissolved in an aromatic organic solvent. The ink B, the ink C, and the ink D are inks in which the quantum dot light-emitting material is dispersed in an acryl resin, and are manufactured by different ink manufacturers. The ink B and the ink D are indium-phosphorus quantum dot materials. The ink C is a cadmium-selenium based quantum dot material. Further, the material of the partition wall is an acrylic resin containing all of the fluorine compound.

That is, as shown in (table 1), in the case of the ink a and the ink B having the receding contact angle of 15 ° or more, no ink wets the partition walls and remains after contraction of the ink. However, in the case of ink C and ink D having a receding contact angle of 15 ° or less, it was found that wetting residue of ink occurred on the partition walls.

Under the above-described combination of materials, as shown in fig. 10C, the light-emitting layer 21 is not formed on the top portions 23Ba of the first partition walls 23B. Therefore, the light-emitting layer 21 is received in the first partition wall 23B. Thereby, the color conversion device 20B capable of completely preventing undesired light emission from outside the light emitting region of the light emitting layer 21 can be obtained.

(modification 3)

Next, a color conversion device 20C according to modification 3 of the present embodiment will be described with reference to fig. 11A to 11C.

Fig. 11A is a top view of a color conversion device 20C according to modification 3. Fig. 11B is a cross-sectional view taken along line 11B-11B of fig. 11A. Fig. 11C is a cross-sectional view taken along line 11C-11C of fig. 11A.

In addition, in the color conversion device 20 of the above-described embodiment, a description has been given taking as an example a configuration in which one region surrounded by the first partition wall 23 is included in the region surrounded by the second partition wall 24.

However, as shown in fig. 11A to 11C, the color conversion device 20C of modification 3 includes two or more areas surrounded by the first partition wall 23C within the area surrounded by the second partition wall 24C. In this regard, the color conversion device 20C of modification 3 is different from the color conversion device 20 of the above-described embodiment.

Specifically, modification 3 illustrates an example in which four regions surrounded by first partition walls 23C are included in one region surrounded by second partition walls 24C. At this time, as shown in fig. 11C, the pixels of different colors are separated by the second partition walls 24C, respectively.

According to the color conversion device 20C of modification 3, ink can be collectively applied to a plurality of pixels on a line. Therefore, the uniformity of film thickness between pixels is improved.

In general, there is a variation in volume of discharged droplets between nozzles of an inkjet head due to a processing variation of the nozzles. However, according to the color conversion device 20C of modification 3, the light emitting layers 21 of a plurality of pixels are collectively formed by a plurality of nozzles. Therefore, the variation in the volume of the discharged droplets among the nozzles is averaged. This dramatically improves the uniformity of film thickness between pixels.

In modification 3, the diameter of the region surrounded by first partition wall 23C is the same as the length of second partition wall 24C in the short axis direction. For example, as shown in fig. 12, the region surrounded by the first partition wall 23C and the region surrounded by the second partition wall 24C may be formed as, for example, double-circle regions in a plan view. Specifically, the area surrounded by second partition wall 24C may be larger in both the major axis direction and the minor axis direction than the area surrounded by first partition wall 23C.

(other modification example)

The color conversion device, the micro LED display panel, and the like according to the present disclosure have been described above based on the embodiments and the modifications 1 to 3, but the present disclosure is not limited to the embodiments and the modifications 1 to 3.

For example, in the above-described embodiment and modifications 1 to 3, the description has been given of an example in which the shape of the region surrounded by the first partition wall 23, 23B, or 23C defining the light emitting region where the light emitting layer 21 emits light is circular in a plan view. The first partition wall 23, 23B, or 23C may have another shape such as a polygon such as a quadrangle or an oval. Similarly, the shape of the region surrounded by the second partition wall 24 defining the formation region (ink application region) for forming the light-emitting layer 21 in plan view is not limited to an oval, and may be another polygonal shape such as a square.

In the above embodiment and modifications 1 to 3, the description has been given by taking as an example a structure in which the blue light-emitting layer 21b does not contain a quantum dot material, but the invention is not limited thereto. That is, the blue light emitting layer 21b may also contain a quantum dot material. In this case, the blue light-emitting layer 21b contains a quantum dot material that can emit blue light by irradiation with excitation light such as ultraviolet light.

Further, the present disclosure includes an embodiment obtained by applying various modifications that will occur to those skilled in the art to the above-described embodiment and modifications 1 to 3, and an embodiment realized by arbitrarily combining the constituent elements and functions in the embodiment and modifications 1 to 3 within a range that does not depart from the gist of the present disclosure.

In the above-described embodiment and modifications 1 to 3, the structure including the quantum dot material was described as the light-emitting material, but the light-emitting material is not limited to this, and may be a structure including another light-emitting material such as a light-emitting material having a perovskite structure.

Claims (19)

1. A color conversion device having:

a substrate;

a light emitting layer on the substrate and including a light emitting material;

a first partition wall which is in contact with the light-emitting layer and defines a light-emitting region where the light-emitting layer emits light;

a second partition wall which is in contact with the light-emitting layer and defines a formation region in which the light-emitting layer is formed,

the contact area of the light emitting layer with the first partition wall is larger than the contact area of the light emitting layer with the second partition wall.

2. The color conversion apparatus according to claim 1,

the region surrounded by the second partition wall includes two or more regions surrounded by the first partition wall.

3. The color conversion apparatus according to claim 1 or 2,

the first barrier rib and the second barrier rib are provided on one surface of the substrate,

a first distance from the base plate to a top of the first partition wall is shorter than a second distance from the base plate to a top of the second partition wall.

4. The color conversion apparatus according to any one of claims 1 to 3,

the static contact angle of the top of the first partition wall with respect to the ink forming the color conversion layer is smaller than the static contact angle of the top of the second partition wall with respect to the ink forming the color conversion layer.

5. The color conversion apparatus according to claim 4,

a static contact angle of a top portion of the first partition wall with respect to ink forming the color conversion layer and a static contact angle of a top portion of the second partition wall with respect to ink forming the color conversion layer are 40 ° or more and 70 ° or less, and a static contact angle of a side portion of the first partition wall with respect to ink forming the color conversion layer and a static contact angle of a side portion of the second partition wall with respect to ink forming the color conversion layer are 5 ° or more and 40 ° or less.

6. The color conversion apparatus according to any one of claims 1 to 5,

the receding contact angle of the top of the second partition wall with respect to ink forming the color conversion layer is 15 ° or more.

7. The color conversion apparatus according to any one of claims 1 to 6,

the first distance is 3 [ mu ] m or more and 7 [ mu ] m or less,

the second distance is 6 [ mu ] m or more and 8 [ mu ] m or less.

8. The color conversion apparatus according to any one of claims 1 to 7,

the light emitting layer is formed by curing the ink containing the light emitting material,

a stationary contact angle of a top of the first partition wall with respect to the ink is larger than a stationary contact angle of a side of the first partition wall with respect to the ink.

9. The color conversion apparatus according to any one of claims 1 to 8,

the two first partition walls are disposed to face each other in one region surrounded by the second partition walls.

10. The color conversion apparatus according to claim 9,

the shape of the partition sandwiched by the two first partition walls is cylindrical.

11. The color conversion apparatus according to any one of claims 1 to 9,

the first partition is a columnar body and is disposed on a side surface of the second partition.

12. The color conversion apparatus according to any one of claims 1 to 11,

the region surrounded by the second partition wall has a flat shape in a plan view.

13. The color conversion apparatus according to claim 12,

the flat region is disposed obliquely to the long axis direction of the substrate in a plan view.

14. The color conversion apparatus according to any one of claims 1 to 13,

the first partition wall and the second partition wall comprise a fluorine-containing material.

15. The color conversion apparatus according to claim 14,

the fluorine material is unevenly contained in the first partition wall and the second partition wall.

16. A micro LED display panel having:

a color changing apparatus according to any one of claims 1 to 15; and

a light emitting device emitting light incident to the color conversion device.

17. A method of manufacturing a color conversion device, comprising:

a first step of forming a first partition wall that defines a light-emitting region where a light-emitting layer emits light on a substrate;

a second step of forming a second partition wall defining a formation region for forming the light-emitting layer on the substrate; and

a third step of applying ink containing a light-emitting material to a region surrounded by the second partition wall to form the light-emitting layer,

in the first step and the second step, the first partition wall and the second partition wall are formed such that a first distance from the substrate to a top of the first partition wall is shorter than a second distance from the substrate to a top of the second partition wall.

18. The method of manufacturing a color conversion device according to claim 17,

in the third step, the ink is applied using an inkjet method,

the region surrounded by the second partition wall has a flat shape in a plan view,

the direction of application of the ink is perpendicular to the longitudinal direction of the region surrounded by the second partition walls.

19. A manufacturing method of a micro LED display panel using a color conversion device manufactured by the manufacturing method of a color conversion device of claim 17 or claim 18, comprising:

a step of bonding the color conversion device and a light emitting device that emits light incident to the color conversion device.

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