阅读说明：本技术 发光层、发光设备、发光层的制造装置 (Light-emitting layer, light-emitting device, and apparatus for manufacturing light-emitting layer ) 是由 兼弘昌行 石田壮史 仲西洋平 冈本翔太 于 2018-06-15 设计创作，主要内容包括：提供一种发光设备,目的在于提供不包含高温工艺且适于量产的发光层以及具备该发光层的发光设备,所述发光设备包括：发光层,其有分散有量子点的感光性材料形成；第一电极,其形成在所述发光层的下层；第二电极,其形成在所述发光层的上层。(Provided are a light emitting device which does not include a high temperature process and is suitable for mass production, and a light emitting device having the light emitting layer, the light emitting device including: a light-emitting layer formed of a photosensitive material in which quantum dots are dispersed; a first electrode formed on a lower layer of the light-emitting layer; and a second electrode formed on an upper layer of the light emitting layer.)

1. A light-emitting layer is characterized in that the light-emitting layer is formed by a photosensitive material dispersed with quantum dots.

2. The light-emitting layer according to claim 1, wherein the light-emitting layer has quantum dots in which wavelength bands of at least three kinds of fluorescence are respectively different.

3. The light-emitting layer according to claim 1 or 2,

the thickness of the photosensitive material is 10nm to 500 nm.

4. The light-emitting layer according to any one of claims 1 to 3,

the light-emitting layer includes at least one of a photopolymerization initiator and a photoacid generator.

5. The light-emitting layer according to any one of claims 1 to 4,

the light-emitting layer is provided with a negative photosensitive material.

6. The light-emitting layer according to any one of claims 1 to 4,

the light-emitting layer is provided with a positive photosensitive material.

7. A light emitting apparatus, characterized in that the light emitting apparatus comprises:

a light-emitting layer according to any one of claims 1 to 6;

a first electrode provided below the light-emitting layer;

a second electrode disposed on an upper layer of the light emitting layer.

8. The light-emitting device according to claim 7,

the light emitting layer is cut into a plurality of pixel regions.

9. The light-emitting device according to claim 8,

the light-emitting layer provided in a part of the pixel region has quantum dots, and the quantum dots are different from the quantum dots provided in the light-emitting layers provided in different pixel regions.

10. The light-emitting apparatus according to any one of claims 7 to 9,

at least one of the first electrode and the second electrode has a light-transmitting property.

11. The light-emitting apparatus according to any one of claims 7 to 10,

the first electrode has light reflectivity.

12. The light-emitting apparatus according to any one of claims 7 to 10,

the second electrode has light reflectivity.

13. The light-emitting device according to any one of claims 7 to 12,

the first electrode is an anode and the second electrode is a cathode.

14. The light-emitting device according to any one of claims 7 to 12,

the first electrode is a cathode and the second electrode is an anode.

15. An apparatus for manufacturing a light-emitting layer, characterized in that the apparatus for manufacturing a light-emitting layer performs the steps of:

coating a photosensitive material dispersed with quantum dots on a substrate;

forming an exposed region and a non-exposed region in the photosensitive material on the substrate;

removing the photosensitive material in at least a portion of the exposed area or at least a portion of the non-exposed area.

Technical Field

The present invention relates to a light-emitting layer including quantum dots, a light-emitting element including the light-emitting layer, and a light-emitting device including the light-emitting element.

Background

Patent document 1 discloses a method of forming or patterning a nanostructure array. Patent document 2 discloses a method of patterning a quantum dot layer on an element substrate.

Disclosure of Invention

Technical problem to be solved by the invention

The method described in patent document 1 includes a high-temperature process for inactivating the light emission characteristics of the quantum dots, and is difficult to apply to a light-emitting device provided with quantum dots. In addition, in the method described in patent document 2, it is difficult to realize a large-sized and high-definition light emitting device, and the tact time (takttime) is long, so the method described in patent document 2 is not suitable for a mass production process.

The present invention has been made in view of the above problems, and an object of the present invention is to facilitate separation of emission colors in a light-emitting device including a quantum dot in a light-emitting layer.

Technical solution for solving technical problem

In order to solve the above problems, a light-emitting layer according to an embodiment of the present invention is formed of a photosensitive material in which quantum dots are dispersed.

In order to solve the above problem, a manufacturing apparatus of a light-emitting layer according to an aspect of the present invention includes: coating a photosensitive material dispersed with quantum dots on a substrate; forming an exposed region and a non-exposed region in the photosensitive material on the substrate; removing the photosensitive material in at least a portion of the exposed area or at least a portion of the non-exposed area.

Advantageous effects

According to an aspect of the present invention, a light-emitting layer including quantum dots, which is capable of easily realizing a large size and high definition without deactivating the light-emitting characteristics of the quantum dots and shortening the tact time, can be provided.

Drawings

Fig. 1 is a process cross-sectional view showing an example of a method for manufacturing a light-emitting device according to a first embodiment of the present invention.

Fig. 2 is a plan view and a sectional view of a light-emitting device according to a first embodiment of the present invention.

Fig. 3 is a flowchart showing an example of a method for manufacturing a light-emitting device according to a first embodiment of the present invention.

Fig. 4 is a block diagram showing a manufacturing apparatus used for manufacturing a light-emitting layer of a light-emitting device according to a first embodiment of the present invention.

Fig. 5 is a sectional view showing a light emitting mechanism of a light emitting apparatus according to a first embodiment of the present invention.

Fig. 6 is a process cross-sectional view showing an example of a method for manufacturing a light-emitting device according to a second embodiment of the present invention.

Fig. 7 is a sectional view of a light-emitting device according to a third embodiment of the present invention.

Fig. 8 is a flowchart showing an example of a method for manufacturing a light-emitting device according to a third embodiment of the present invention.

Fig. 9 is a sectional view showing a light emitting mechanism of a light emitting apparatus according to a third embodiment of the present invention.

Fig. 10 is a sectional view of a light-emitting device according to a fourth embodiment of the present invention.

Fig. 11 is a sectional view showing a light emitting mechanism of a light emitting apparatus according to a fourth embodiment of the present invention.

Detailed Description

[ first embodiment ]

In this specification, a direction from a light-emitting layer of a light-emitting device to a first electrode is referred to as a "lower direction", and a direction from the light-emitting layer of the light-emitting device to a second electrode is referred to as an "upper direction".

Fig. 2 is an enlarged top view and an enlarged cross-sectional view of the light emitting apparatus 2 relating to the present embodiment. Fig. 2 (a) is a diagram showing the upper surface of the periphery of the pixel of the light-emitting device 2 that transmits the electron-transporting layer 16 and the second electrode 18 a. Fig. 2 (b) is a cross-sectional view taken in a direction corresponding to the arrow in fig. 2 (a).

As shown in fig. 2 (b), the light-emitting device 2 has a structure in which layers are stacked on an array substrate 4 on which TFTs (Thin Film transistors) not shown are formed. The first electrode 8a is electrically connected to the TFT, and includes an edge cap 6 for preventing short-circuiting between the electrodes. The first electrode 8a includes a hole injection layer 10, a hole transport layer 12, a light emitting layer 14, an electron transport layer 16, and a second electrode 18 a. As shown in fig. 2, the regions surrounded by the edge cover 6 are pixel regions of various colors including a red pixel region RP, a green pixel region GP, and a blue pixel region BP.

A hole injection layer 10, a hole transport layer 12, and a light emitting layer 14 are formed in this order from below on the upper layer of the first electrode 8a on the array substrate 4. The array substrate 4 is a transparent substrate formed with TFTs corresponding to each of the first electrodes 8a as each pixel. The substrate may be made of glass or flexible plastic. When plastic is used as the array substrate 4, the flexible light emitting apparatus 2 can be obtained.

The TFT material includes an amorphous silicon semiconductor, a low-temperature polysilicon semiconductor, an oxide semiconductor, and the like, and an oxide semiconductor is preferably used. The oxide semiconductor has high mobility and small characteristic variation compared with amorphous silicon. Therefore, the TFT including an oxide semiconductor is suitable for a next-generation display device with higher definition. In addition, the oxide semiconductor is formed by a simple process compared to low-temperature polysilicon. Therefore, a TFT including an oxide semiconductor has an advantage that it can be applied to a device requiring a large area.

Examples of the oxide semiconductor include a compound (In-Ga-Zn-O) composed of indium (In), gallium (Ga), zinc (Zn), and oxygen (O), a compound (In-Tin-Zn-O) composed of indium (In), Tin (Tin), zinc (Zn), and oxygen (O), and a compound (In-Al-Zn-O) composed of indium (In), aluminum (Al), zinc (Zn), and oxygen (O).

The first electrode 8a is an anode and has light transmittance. The first electrode 8a may also include a transparent oxide such as ITO, IZO, or ISO. The hole injection layer 10 may also include PEDOT/PSS, and Clevios (registered trademark) AI4083, for example. The hole transport layer 12 may also include organic materials such as PVK, poly-TPD, CBP, NPD, or TFB. In addition, the hole transport layer 12 may also include NiO or MoO₃And the like.

An electron transport layer 16 and a second electrode 18a are formed on the upper surface of the light-emitting layer 14 in this order from below. Generally, ZnO nanoparticles are often used as the electron transport layer 16. The electron transport layer 16 may include Alq3, PBD, TPBi, BCP, Balq, CDBP, or the like. The second electrode 18a is a cathode and has light reflectivity. The second electrode 18a may also include Mg, Ca, Na, Ti, In, Ir, Li, Gd, Al, Ag, Zn, Pb, Ce, Ba, LiF/Al, LiO₂Al, LiF/Ca or BaF₂Ca, etc. Further, an electron injection layer may be formed between the electron transport layer 16 and the second electrode 18 a.

Here, the light emitting layer 14 has quantum dots (semiconductor nanoparticles). The quantum dots are dispersed in the light emitting layer 14. The light-emitting layer provided in a part of the plurality of pixel regions has quantum dots, and the quantum dots are different from the quantum dots provided in the light-emitting layers provided in different pixel regions. For example, as shown in fig. 1 (a), the light emitting layers 14 formed in the respective pixel regions RP, GP, and BP have three kinds of quantum dots of red quantum dots RD, green quantum dots GD, and blue quantum dots BD, respectively.

The quantum dots RD, GD, and BD emit fluorescence in different wavelength bands, and emit red, green, and blue as fluorescence, respectively. In addition to the quantum dots RD, GD, and BD, the light-emitting layer 14 may also include, for example, quantum dots that emit yellow as fluorescent light. The quantum dots RD, GD, and BD have a core-shell structure and may also include, for example, CdSe/ZnSe, CdSe/ZnS, CdS/ZnSe, CdS/ZnS, ZnSe/ZnS, InP/ZnS, or ZnO/MgO, etc.

Here, the blue light is light having an emission center wavelength in a wavelength band of 400nm or more and 500nm or less. The green light is light having an emission center wavelength in a wavelength band of more than 500nm and 600nm or less. Red light is light having an emission center wavelength in a wavelength band of more than 600nm and 780nm or less.

Next, a method for manufacturing the light-emitting device 2 according to the present embodiment will be described with reference to fig. 1 and 3. Fig. 1 is a process sectional view for explaining a method of manufacturing a light emitting device 2. Fig. 3 is a flowchart of a method of manufacturing the light emitting device 2 according to the present embodiment.

First, the array substrate 4 including the TFTs and various wirings connected to the TFTs is prepared, and the first electrodes 8a electrically connected to the TFTs are formed on the array substrate 4 (S10). Next, the edge cover 6 is formed between the first electrodes 8a (S12). The hole injection layer 10 and the hole transport layer 12 are formed in this order from below on the first electrode 8a (S14), and the structure shown in fig. 1 (a) is obtained. The method of manufacturing each element up to this point may be a conventionally known method as appropriate.

Next, a method for manufacturing the light-emitting layer 14 will be described. The light-emitting layer 14 according to the present embodiment is manufactured by photolithography from a photosensitive material in which quantum dots are dispersed. First, as shown in fig. 1 (b), a photosensitive material 14a in which red quantum dots RD are dispersed is coated on the hole transport layer 12 as a base material (S16). The photosensitive material 14a may be applied by a known method such as a spin coating method, a spray coating method, a casting method, a printing method including an ink jet method, or an LB method. The thickness of the photosensitive material 14a is preferably 10nm or more, and more preferably 20nm or more, from the viewpoint of ensuring a film thickness that facilitates coating control and pattern control. In addition, the thickness of the photosensitive material 14a is preferably 500nm or less, and more preferably less than 200nm, from the viewpoint of easy injection of the carrier and improvement of the light emission efficiency.

The photosensitive material 14a may also include a photosensitive resin, such as SU-8 (japanese chemical), KI series (hitachi chemical), AZ photoresist (Merck), or chemicals. The photosensitive material 14a may contain at least one of a photopolymerization initiator and a photoacid generator. The concentration of the quantum dots with respect to the photosensitive material 14a can be appropriately selected so that coating can be easily performed and a desired film thickness can be obtained. Specifically, the concentration of the quantum dots with respect to the photosensitive material 14a is preferably in the range of 1 to 50 wt%, and more preferably in the range of 10 to 40 wt%. If less than the above concentration, desired light emitting characteristics cannot be sufficiently obtained, and a light emitting layer of a light emitting device cannot be formed. Further, if it exceeds the above range, the stability of the formed film may be deteriorated due to the increase of the quantum dot component, and the flatness and patterning accuracy may be deteriorated.

Next, as shown in fig. 1 c, a mask pattern M is provided above the photosensitive material 14a (S18), and light is irradiated from above the mask pattern M to expose the photosensitive material 14a (S20). That is, in the photosensitive material 14a, an exposed region is formed at a position where the mask pattern M does not exist above, and a non-exposed region is formed at a position where the mask pattern M exists above. For example, i-line (wavelength 365nm) may be used as light for exposure, but may be appropriately selected depending on the material. Further, the exposure amount is preferably 20mJ/cm from the viewpoint of improving the pattern accuracy and reducing the film loss²The above. Further, the exposure amount is preferably 1000mJ/cm from the viewpoint of suppressing an increase in the tact time and reducing damage to other members²The following.

At this time, the mask pattern M is disposed over the green pixel region GP, the blue pixel region BP, and the edge cover 6. Therefore, the light applied to the green pixel region GP, the blue pixel region BP, and the edge cover 6 is blocked by the mask pattern M to become a non-exposure region. Therefore, only the photosensitive material 14a formed on the hole transport layer 12 in the red pixel region RP is exposed to light to become an exposed region. The photosensitive material 14a in the exposed region is altered to become the light-emitting layer 14.

Next, the photosensitive material 14a is washed with a developer, and the photosensitive material 14a is removed (S22). The developer is, for example, TMAH, but may be appropriately selected according to the photosensitive material 14 a. Here, the photosensitive material 14a is a negative photosensitive material which is hardly soluble in a developer by exposure. Therefore, as shown in fig. 1 (d), only the light-emitting layer 14, which is the exposed photosensitive material 14a, does not dissolve in the developer, but remains on the hole transport layer 12. Therefore, the light emitting layer 14 having the red quantum dots RD is formed only on the red pixel region RP.

The above S16, S18, S20 and S22 are repeated to form the light emitting layer 14 having the green quantum dots GD in the green pixel region GP and the light emitting layer 14 having the blue quantum dots BD in the blue pixel region BP. Thereby, the structure shown in fig. 1 (e) is obtained. Finally, the electron transport layer 16 and the second electrode 18a are formed in this order from below on the light-emitting layer 14 (S24). The electron transport layer 16 and the second electrode 18a may be formed by a sputtering method, a vacuum evaporation method, or the like, in addition to the printing method described above.

In the above, the light emitting apparatus 2 shown in (f) of fig. 1 is manufactured. In addition, in the manufacturing process of the above-described light emitting device 2, actually, after the photosensitive material 14a is applied, a pre-baking may be performed to remove the solvent from the photosensitive material 14 a. In addition, after the development of the light emitting layer 14, a post-baking may also be performed to ensure close contact between the light emitting layer 14 and the substrate and to improve the resistance of the subsequent process to the treatment.

Fig. 4 is a block diagram showing a manufacturing apparatus 20 for a light-emitting layer used for manufacturing the light-emitting layer 14 in the manufacturing process of the light-emitting device 2. The manufacturing apparatus 20 of the light emitting layer includes a controller 22, a coating device 24, an exposure device 26, and a developing device 28. The coating device 24 coats a base material of the photosensitive material 24a in which the quantum dots are dispersed. The exposure device 26 sets a mask pattern M above the photosensitive material 24a on the substrate, and irradiates light onto at least a part of the photosensitive material 24 a. After the light is irradiated to the photosensitive material 24a, the developing device 28 removes at least a portion of the photosensitive material 24 a. The controller 22 controls the coating device 24, the exposure device 26, and the developing device 28.

In the above manufacturing method, there is no high temperature process during and after the formation of the light emitting layer having the quantum dots. Therefore, the possibility that the light emitting characteristics of the quantum dot are inactivated and fluorescence is not generated is reduced. Therefore, the manufacturing yield of the light emitting device 2 is improved by the above manufacturing method. In addition, in the above-described manufacturing method, the light-emitting layer 14 may be formed using a photolithography method. Therefore, the light-emitting layer 14 can be formed with high-precision patterning while suppressing an increase in tact time. Therefore, since the light emitting device 2 is more easily increased in size or high in definition, the above manufacturing method is more suitable for mass production.

In the above-described manufacturing method, the quantum dots are distributed inside the photosensitive material 14a and the light-emitting layer 14. Therefore, when the light emitting layer 14 is formed or in a process after the light emitting layer 14 is formed, direct contact of the quantum dot with oxygen, moisture, or the like is reduced, and damage to the quantum dot can be reduced. Therefore, the manufacturing yield of the light emitting device 2 is further improved by the above manufacturing method.

Fig. 5 is a sectional view illustrating a light emitting structure of the light emitting apparatus 2 according to the present embodiment. Fig. 5 shows a case where fluorescence is generated from the green quantum dots GD of the light-emitting device 2.

First, as shown in fig. 5, a voltage is applied between two electrodes in the green pixel region GP. Specifically, by controlling the TFTs on the array substrate 4, a voltage is applied between the two electrodes of the first electrode 8a (pixel electrode) belonging to the green pixel region GP and the opposing second electrode 18 a. The potential difference is generated in such a manner that the first electrode 8a as an anode has a higher potential than the second electrode 18a as a cathode. Thereby, holes are injected from the first electrode 8a and the hole injection layer 10 into the hole transport layer 12, and electrons are injected from the second electrode 18a into the electron transport layer 16. The hole transport layer 12 transports holes to the light emitting layer 14, and the electron transport layer 16 transports electrons to the light emitting layer 14. Further, in the green quantum dots GD in the light emitting layer 14, excitons are generated by hole and electron recombination. When the excitons transition to the ground state, green fluorescence is generated in the green quantum dots GD.

Among the fluorescence generated in the green quantum dots GD, the fluorescence generated toward the lower side transmits the first electrode 8a as a transparent electrode and the array substrate 4 as a transparent substrate, and is emitted to the lower side of the light emitting device 2. On the other hand, among the fluorescence generated from the green quantum dots GD, the fluorescence generated upward is reflected by the second electrode 18a as a reflective electrode. Therefore, the fluorescence is also emitted to the lower side of the light emitting device 2. Since the fluorescence generated in the green quantum dots GD is emitted downward, the light emitting efficiency is improved. The above-described light emitting mechanism is the same for the fluorescence generated in the red pixel region RP and the blue pixel region BP.

[ second embodiment ]

Fig. 6 is a process sectional view showing another example of the method for manufacturing the light emitting device 2 according to the present embodiment. The light-emitting device 2 according to the present embodiment differs from the light-emitting device 2 according to the above-described embodiment only in that a light-emitting layer 15 containing a positive photosensitive material is provided instead of the light-emitting layer 14. A method for manufacturing the light-emitting device 2 according to the present embodiment will be described with reference to fig. 3 and 6.

First, as in the manufacturing method of the light emitting device 2 described above, an array substrate on which the first electrodes 8a electrically connected to the TFTs are formed is manufactured, and the edge cover 6 is formed between the electrodes. The hole injection layer 10 and the hole transport layer 12 are formed on the upper layer of the first electrode 8a (S10, S12, S14), and the structure shown in fig. 6 (a) is obtained. Next, as shown in fig. 6 (b), a positive photosensitive material in which red quantum dots RD are dispersed is applied on the hole transport layer 12 as a substrate (S16), and the photosensitive material is cured by pre-baking or the like to obtain the light-emitting layer 15.

Next, as shown in fig. 6 c, a mask pattern M is provided only above the red pixel region RP (S18), and light is irradiated from above the light-emitting layer 15 to expose the light-emitting layer 15 (S20). The light-emitting layer 15 is converted into a light-exposed light-emitting layer 15a having improved solubility in a developer by exposure to light. Therefore, the exposed light-emitting layer 15a is removed by cleaning the light-emitting layer 15 and the exposed light-emitting layer 15a with a developer (S22). Therefore, the light emitting layer 15 having the red quantum dots RD is formed only in the red pixel region RP.

The above S16, S18, S20 and S22 are repeated to form the light emitting layer 15 having the green quantum dots GD in the green pixel region GP and the light emitting layer 15 having the blue quantum dots BD in the blue pixel region BP. Thereby, the structure shown in fig. 6 (e) is obtained. Finally, the electron transport layer 16 and the second electrode 18a are formed in this order from below on the light-emitting layer 14 (S24). In the above, the light emitting apparatus 2 shown in (f) of fig. 6 is manufactured.

In the method of manufacturing the light emitting device 2 according to the present embodiment, when the light emitting layer 15 is formed, the light emitting layer 15a after exposure is removed, and the light emitting layer 15 that is not exposed remains. That is, the light emitting device 2 includes the light emitting layer 15 that is not exposed to light. Therefore, since the quantum dots provided in the light-emitting layer 15 are not irradiated with light during exposure, the possibility of the quantum dots being damaged during exposure is reduced. Therefore, the manufacturing yield of the light emitting device 2 is further improved by the above manufacturing method. In addition, the light emitting mechanism of the light emitting device 2 according to the present embodiment may be the same as the light emitting mechanism of the light emitting device 2 according to the above-described embodiment.

[ third embodiment ]

Fig. 7 is a sectional view of the light emitting device 2 according to the present embodiment. The light emitting device 2 according to the present embodiment includes a first electrode 8b and a second electrode 18b instead of the first electrode 8a and the second electrode 18 a.

The light emitting device 2 according to the present embodiment includes a first electrode 8b, an electron transport layer 16, and a light emitting layer 14 in this order from below in each pixel region surrounded by the edge cover 6 on the array substrate 4. The first electrode 8b is a cathode and has light reflectivity. The first electrode 8b may also comprise the same material as the second electrode 18 a.

The hole transport layer 12, the hole injection layer 10, and the second electrode 18b are formed in this order from below on the light-emitting layer 14. The second electrode 18b is an anode and has light transmittance. The second electrode 1b may also comprise the same material as the first electrode 8 a.

Next, a method for manufacturing the light emitting device 2 according to the present embodiment will be described with reference to fig. 8. Fig. 8 is a flowchart showing a method of manufacturing the light-emitting device 2 according to the present embodiment.

First, as in the method of manufacturing the light emitting device 2 described above, the array substrate 4 including the TFTs and various wirings connected to the TFTs is fabricated, and the first electrodes 8b electrically connected to the TFTs are formed on the array substrate 4. Next, the edge cover 6 is formed between the first electrodes 8 b. Next, the electron injection layer 16 is formed on the upper layer of the first electrode 8b in this order from below (S34).

Next, the light-emitting layer 14 is formed in the red pixel region RP. The light-emitting layer 14 may be formed by the same method as the formation of the light-emitting layer 14. That is, the photosensitive material 14a may be applied on the electron injection layer (S36), a mask pattern M may be provided (S38), the photosensitive material 14a may be exposed (S40), and a portion of the photosensitive material 14a may be removed (S42). Thereby, the light-emitting layer 14 in which the red quantum dots RD are dispersed is formed in the red pixel region RP. Similarly, in the green pixel region GP and the blue pixel region BP, the light-emitting layer 14 in which the green quantum dots GD and the blue quantum dots BD are dispersed is formed by repeating S36, S38, S40, and S42.

Finally, as in the above-described method for manufacturing the light-emitting device 2, the hole transport layer 12, the hole injection layer 10, and the second electrode 18b are formed in this order from below on the light-emitting layer 14 (S44). Thereby, the light emitting apparatus 2 according to the present embodiment is obtained.

In the above-described method of manufacturing the light-emitting device 2, when the electron injection layer 16 is formed, the light-emitting layer 14 provided with quantum dots does not exist. Therefore, even if a high temperature process is applied in the formation of the electron injection layer 16, no damage is caused to the quantum dots.

Fig. 9 is a sectional view illustrating a light emitting mechanism of the light emitting device 2 according to the present embodiment. Fig. 9 shows a case where fluorescence is generated from the green quantum dots GD of the light-emitting device 2, as in fig. 5.

First, as shown in fig. 9, a voltage is applied between two electrodes in the green pixel region GP. Specifically, by controlling the TFTs on the array substrate 4, a voltage is applied between two electrodes of the first electrode 8b (pixel electrode) belonging to the green pixel region GP and the opposing second electrode 18 b. The potential difference is generated in such a manner that the first electrode 8b as an anode has a lower potential than the second electrode 18b as a cathode. Thereby, electrons are injected from the first electrode 8b into the electron transport layer 16, and holes are injected from the second electrode 18b and the hole injection layer 10 into the hole transport layer 12. The mechanism for generating fluorescence in the light-emitting layer 14 is the same as that described with reference to fig. 5.

Among the fluorescence generated in the green quantum dots GD, the fluorescence generated toward the upper side transmits the hole transport layer 12 and the hole injection layer 10, which are transparent thin films, and the second electrode 18b, which is a transparent electrode, and is emitted toward the upper side of the light emitting device 2. On the other hand, among the fluorescence generated from the green quantum dots GD, the fluorescence generated downward is reflected by the first electrode 8b as a reflective electrode. Therefore, the fluorescence is also emitted above the light emitting device 2. Since the fluorescence generated in the green quantum dots GD is emitted upward, the light emitting efficiency is improved.

Further, in the light emitting device 2 relating to the present embodiment, the direction of extracting fluorescence is above the light emitting device 2 where the TFT is not formed. Therefore, the opening through which the fluorescence emitted from the light emitting layer 14 passes can be widened. Therefore, the light emitting device 2 according to the present embodiment can further improve the light emitting efficiency.

[ fourth embodiment ]

Fig. 10 shows a cross-sectional view of the light-emitting device 2 according to the present embodiment. The light emitting apparatus 2 relating to the present embodiment is different from the light emitting apparatus 2 relating to the previous embodiment only in that: instead of the first electrode 8b and the second electrode 18b, a first electrode 8c and a second electrode 18c are provided.

The first electrode 8c is a cathode and has light transmittance. The first electrode 8c may also include the same material as the material included in the first electrode 8 a. The second electrode 18c is an anode and has light reflectivity. The second electrode 18c may also include the same material as the material included in the second electrode 18 a.

The light emitting apparatus 2 relating to the present embodiment is different from the light emitting apparatus 2 relating to the previous embodiment only in that: in the first electrode and the second electrode, the properties of the materials and the electrodes used are opposite. Therefore, the light emitting device 2 according to the present embodiment can be manufactured by the same manufacturing method as the light emitting device 2 according to the foregoing embodiment. Therefore, in the present embodiment, even if a high temperature process is applied in forming the electron injection layer 16, no damage is caused to the quantum dots.

Fig. 11 is a sectional view illustrating a light emitting mechanism of the light emitting device 2 according to the present embodiment. Fig. 11 shows a case where fluorescence is generated from the green quantum dots GD of the light-emitting device 2, as in fig. 5 and 9. The mechanism for generating fluorescence from the light-emitting layer of the light-emitting device 2 according to the present embodiment is the same as the mechanism described with reference to fig. 9. Further, as described with reference to fig. 5, in the light emitting device 2 relating to the present embodiment, fluorescence is also emitted below the light emitting device 2. Since the fluorescence generated in the green quantum dots GD is emitted downward, the light emitting efficiency is improved.

[ conclusion ]

The light-emitting layer of the first embodiment is formed of a photosensitive material in which quantum dots are dispersed.

In the second form, the light-emitting layer has quantum dots in which at least three kinds of fluorescence have different wavelength bands.

In the third aspect, the thickness of the light-emitting layer is 10nm or more and 500nm or less.

In the fourth aspect, the light-emitting layer includes at least one of a photopolymerization initiator and a photoacid generator.

In the fifth aspect, the light-emitting layer is a negative photosensitive material.

In the sixth aspect, the light-emitting layer is a positive photosensitive material.

Form seven relates to a light emitting device, comprising: a light emitting layer; a first electrode provided below the light-emitting layer; a second electrode disposed on an upper layer of the light emitting layer.

In the configuration eight, the light emitting layer is cut into a plurality of pixel regions.

In the ninth aspect, the light-emitting layer provided in a part of the pixel region includes quantum dots, and the quantum dots are different from the quantum dots provided in the light-emitting layers provided in different pixel regions.

In an embodiment, at least one of the first electrode and the second electrode has a light-transmitting property.

In the eleventh aspect, the first electrode has light reflectivity.

In the twelfth aspect, the second electrode has light reflectivity.

In configuration thirteen, the first electrode is an anode and the second electrode is a cathode.

In form fourteen, the first electrode is a cathode and the second electrode is an anode.

The manufacturing apparatus of the light emitting layer of the fifteenth aspect performs the steps of: coating a photosensitive material dispersed with quantum dots on a substrate; forming an exposed region and a non-exposed region in the photosensitive material on the substrate; removing the photosensitive material in at least a portion of the exposed area or at least a portion of the non-exposed area.

A method for manufacturing a light-emitting layer having the sixteenth aspect, comprising: a coating step of coating a photosensitive material in which quantum dots are dispersed on a base material; an exposure step of forming an exposure region and a non-exposure region in the photosensitive material on the substrate; a developing process of removing the photosensitive material in at least a part of the exposed region or at least a part of the non-exposed region after the exposing process.

In the seventeenth aspect, the photosensitive material includes at least one of a photopolymerization initiator and a photoacid generator.

The method of manufacturing a light-emitting device according to the eighteenth aspect includes the method of manufacturing a light-emitting layer.

In the nineteenth aspect, the method further includes an edge mask forming step of forming an edge mask for cutting the photosensitive material into a plurality of pixel regions.

In the mode twenty, a light-emitting layer having quantum dots of a different kind from the quantum dots included in the light-emitting layers formed in the different pixel regions is formed in a part of the pixel region.

In the twenty-first aspect, the method further comprises: a first electrode forming step of forming a first electrode on a lower layer than the photosensitive material; and a second electrode forming step of forming a second electrode on an upper layer of the photosensitive material.

In the twenty-two aspect, the photosensitive material in at least a part of the exposed region in the photosensitive material is removed in the developing step.

In the twenty-third aspect, the photosensitive material in at least a part of the non-exposed region in the photosensitive material is removed in the developing process.

In the twenty-four aspect, in the exposure step, the exposure region and the non-exposure region are formed by providing a mask pattern above the photosensitive material.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention. Further, new technical features can be formed by combining the technical means disclosed in the respective embodiments.

Description of the reference numerals

2 light emitting device

6 bank layer

8 a-8 c first electrode

14/15 light-emitting layer

18 a-18 c second electrode

20 light-emitting layer manufacturing apparatus

RP/GP/BP pixel region

RD/GD/BD quantum dot

M mask pattern