Display device and method for manufacturing the same

Abstract

LED display devices emit light in all directions. Therefore, light is absorbed by peripheral insulating films for insulation of wiring, protective films, partition walls, and the like, and the light-extraction efficiency of a display becomes reduced, resulting in insufficient luminance. According to the present invention, such a problem is solved. This display device comprises at least: a metal wiring; a cured film; and a plurality of light-emitting elements. Each of the light-emitting elements is equipped with a pair of electrode terminals on one surface thereof. The pair of electrode terminals are connected to a plurality of strands of the metal wiring extending in the cured film. The plurality of strands of the metal wiring are configured to maintain electrical insulating properties due to the cured film. The cured film is obtained by curing a resin composition containing a resin (A). The transmittance of the cured film with respect to light having a wavelength of 450 nm is 80-100% at a thickness standard of 5 μm of the cured film.

Description

Technical Field

[0001] The present invention relates to a display device such as an LED display and a manufacturing method thereof.

Background Art

[0002] In recent years, from the perspective of further improving the performance of displays, as a new display technology following liquid crystal, plasma displays, and organic EL displays, a light-emitting diode (hereinafter sometimes referred to as LED) is arranged in the same number as the number of pixels to form an LED display. In particular, a mini-LED display with the size of the LED serving as a light source reduced from about 1 mm in the conventional case to 100 - 700 μm, and a micro-LED display miniaturized to 100 μm or less have attracted attention, and research and development are being actively carried out. The main features of mini-LED displays and micro-LED displays include high contrast, high-speed response, low power consumption, wide viewing angle, etc. It is expected to be widely applied not only to conventional TVs, smartphones, smartwatches and other wearable display applications, but also to new applications with high potential such as signage, AR, VR, and even transparent displays capable of displaying spatial images.

[0003] Various forms have been proposed for the practical application and performance improvement of LED display devices. For example, a form in which micro-LEDs are arranged on a multilayer flexible circuit board (see Patent Document 1), and a form in which a bank layer and trace lines are provided on a display substrate, and micro-LEDs and micro-driver chips are arranged thereon (see Patent Document 2) have been proposed. Also, a planarization film is formed on a growth substrate on which a light-emitting element body having an electrode pad is integrally formed, the planarization film on the electrode pad is removed to expose the electrode pad, an outer electrode pad connected to the electrode pad is formed on the planarization film, and the outer electrode pad is arranged so as to face the circuit-side electrode portion with respect to a circuit board on which a circuit-side electrode portion is formed, and a form in which the front external electrode pad and the circuit-side electrode portion are electrically connected (see Patent Document 3), etc. have been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the LED display device described in the above documents, since light is generated in all directions, the light is absorbed by the insulating film for wiring insulation, the protective film, the partition wall, etc. around it, and there is a problem that the light extraction efficiency as a display becomes low and the brightness becomes insufficient.

Means for Solving the Problems

[0006] In order to solve the above problems, the present invention has the following configuration.

[0007] [1] A display device having at least a metal wiring, a cured film, and a plurality of light-emitting elements, wherein the light-emitting element is provided with a pair of electrode terminals on either one surface, the pair of electrode terminals are connected to a plurality of the metal wirings extending in the cured film, the plurality of the metal wirings are configured to maintain electrical insulation by the cured film, the cured film is a film obtained by curing a resin composition containing a resin, and the transmittance of light with a wavelength of 450 nm at a thickness reference of 5 μm of the cured film is 80% or more and 100% or less.

[0008] [2]A method for manufacturing a display device having at least a metal wiring, a cured film, and a plurality of light-emitting elements, the method including: a step (D1) of disposing the light-emitting elements on a support substrate; a step (D2) of forming a resin film made of a resin composition containing a resin on the support substrate and on the light-emitting elements; a step (D3) of forming a plurality of through-opening patterns in the resin film by exposing and developing the resin film; a step (D4) of curing the resin film to form the cured film having a light transmittance of 80% or more and 100% or less for light with a wavelength of 450 nm at a thickness reference of 5 μm; and a step (D5) of forming the metal wiring on at least a part of the surface of the cured film and in the opening patterns of the cured film.

[0009] [3]A method for manufacturing a display device having at least a metal wiring, a cured film, and a plurality of light-emitting elements, the method including: a step (E1) of disposing metal pads on a support substrate; a step (E2) of forming a resin film made of a resin composition containing a resin on the support substrate and on the metal pads; a step (E3) of forming a plurality of through-opening patterns in the resin film by exposing and developing the resin film; a step (E4) of curing the resin film to form the cured film having a light transmittance of 80% or more and 100% or less for light with a wavelength of 450 nm at a thickness reference of 5 μm; a step (E5) of forming the metal wiring on at least a part of the surface of the cured film and in the opening patterns of the cured film; and a step (E6) of disposing the light-emitting elements on the cured film so as to maintain electrical connection with the metal wiring. [Effects of the Invention]

[0010] The display device of the present invention can provide a display device with high light extraction efficiency and sufficient luminance. [Brief Description of the Drawings]

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, a preferred embodiment of the display device of the present invention will be specifically described. However, the present invention is not limited to the following embodiments and can be variously modified and implemented according to the purpose and application.

[0013] The display device of the present invention is a display device having at least metal wiring, a cured film, and a plurality of light-emitting elements. Each of the light-emitting elements has a pair of electrode terminals on one surface, and the pair of electrode terminals are connected to a plurality of the metal wirings extending in the cured film. The plurality of metal wirings are configured to maintain electrical insulation by the cured film. The cured film is a film obtained by curing a resin composition containing a resin, and the transmittance of light with a wavelength of 450 nm at a thickness reference of 5 μm of the cured film is 80% or more and 100% or less.

[0014] The display device of the present invention will be described with reference to FIG. 1 as an example of one aspect.

[0015] In FIG. 1, a display device 1 arranges a plurality of light-emitting elements 2 on a counter substrate 5, and arranges a cured film 3 on the light-emitting elements 2. The area above the light-emitting elements refers to not only the surface of the light-emitting elements but also any area above the support substrate and the light-emitting elements. In the embodiment shown in FIG. 1, an example is illustrated in which a plurality of cured films 3 are further laminated on the cured film 3 arranged so as to be in contact with at least a part of the light-emitting elements 2, and a total of three layers are laminated. However, the cured film 3 may be a single layer. The light-emitting element 2 includes a pair of electrode terminals 6 on the surface opposite to the surface in contact with the counter substrate 5, and each electrode terminal 6 is connected to a metal wiring 4 extending in the cured film 3. Note that as long as the plurality of metal wirings 4 extending in the cured film 3 are covered by the cured film 3, the cured film 3 also functions as an insulating film, and thus has a configuration for maintaining electrical insulation. The configuration in which the metal wiring maintains electrical insulation means that (A) the necessary part of the electrical insulation of the metal wiring is covered by a cured film obtained by curing a resin composition containing a resin. Further, the light-emitting element 2 is electrically connected to a driving element 8 added to a light-emitting element driving substrate 7 provided at a position facing the counter substrate 5 through the metal wirings 4 and 4c, so that the light emission of the light-emitting element 2 can be controlled. Further, the light-emitting element driving substrate 7 is electrically connected to the metal wiring 4 via, for example, a solder bump 10. Further, a barrier metal 9 may be arranged to prevent the diffusion of metals such as the metal wiring 4. Note that hereinafter, the metal wiring 4c in the drawing may penetrate the light-emitting element driving substrate 7 and be connected to the driving element 8.

[0016] The cured film 3 is a film obtained by curing a resin composition containing a resin (A) described later, and it is important that the light transmittance at a wavelength of 450 nm with a thickness reference of 5 μm of the cured film 3 is 80% or more and 100% or less. Thereby, it is possible to suppress the light emitted from the light-emitting element 2 in all directions from being absorbed in the cured film 3, improve the light extraction efficiency, and improve the luminance. From the viewpoint of improving the luminance, it is more preferable that the light transmittance at a wavelength of 450 nm with a thickness reference of 5 μm is 90% or more and 100% or less.

[0017] Regarding the measurement of the light transmittance at a wavelength of 450 nm with a reference thickness of 5 μm of the hard film, it may be measured by peeling off the hard film of the display device, or the light transmittance of the hard film produced under the conditions of the method for evaluating the light transmittance of the hard film described later may be measured. Further, when forming a plurality of hard films, any of the hard films may be used for measurement.

[0018] The material of the metal wiring 4 is not particularly limited, and known materials can be used. For example, gold, silver, copper, aluminum, nickel, titanium, molybdenum, and alloys containing these may be mentioned, and copper is preferable. Note that the metal wiring 4 may include an electrode.

[0019] In the display device of the present invention, the metal wiring may be a conductive film.

[0020] The conductive film is not particularly limited. For example, compounds mainly containing oxides of at least one element among indium, gallium, zinc, tin, titanium, and niobium, organic substances, and photosensitive conductive pastes containing conductive particles may be mentioned, but other known ones may also be used. Specific examples of the compounds mainly containing oxides of at least one element among indium, gallium, zinc, tin, titanium, and niobium include indium tin zinc oxide (ITZO), indium gallium zinc oxide (IGZO: InGaZnO), zinc oxide (ZnO), indium zinc oxide (IZO), indium gallium oxide (IGO), indium tin oxide (ITO), and indium oxide (InO).

[0021] These conductive films can be formed, for example, by wet plating such as electroless plating and electrolytic plating, CVD chemical vapor deposition methods (CVD) such as thermal CVD, plasma CVD, and laser CVD, dry plating methods such as vacuum evaporation, sputtering, and ion plating, or a method in which a metal foil is bonded to a substrate and then etching is performed.

[0022] Regarding a photosensitive conductive paste containing an organic substance and conductive particles, examples of the organic substance include an epoxy resin, a phenoxy resin, an acrylic copolymer, an epoxy carboxylate compound, and the like. Two or more of these may be contained. An organic substance having a urethane bond may also be contained. By containing an organic substance having a urethane bond, the flexibility of the wiring can be improved. Further, the organic substance preferably exhibits photosensitivity, and a fine wiring pattern can be easily formed by photolithography. The photosensitivity is exhibited, for example, by containing a photoinitiator and a component having an unsaturated double bond.

[0023] The conductive particles in the present invention refer to particles composed of a substance having an electrical resistivity of 10 -5 Ω·m or less. Examples of the material constituting the conductive particles include silver, gold, copper, platinum, lead, tin, nickel, aluminum, tungsten, molybdenum, chromium, titanium, indium, alloys of these metals, and carbon particles. Note that the conductive film includes an electrode. As a display device using a conductive film, an example is shown in FIGS. 28 and 29.

[0024] As another embodiment of the present invention, as shown in FIG. 17, a configuration is exemplified in which a cured film 22 is provided so as to be in contact with at least a part of the light-emitting element 2 with respect to the display device of FIG. 1. The cured film 22 arranged so as to be in contact with at least a part of the light-emitting element 2 may be composed of a cured film obtained by curing a resin composition or a resin sheet containing a resin, or may be composed of a material other than the cured film obtained by curing a resin composition or a resin sheet containing a resin, and known materials such as an epoxy resin, a silicone resin, and a fluororesin may be used.

[0025] In the present invention, the light-emitting element driving substrate 7 includes a substrate having an element having a driving function and the like, and it is preferable that the driving element 8 is connected.

[0026] The light-emitting element driving substrate 7 is not particularly limited, and known ones can be used. For example, a glass substrate, a sapphire substrate, a printed wiring board, a TFT array substrate, ceramics, etc. can be mentioned.

[0027] In the present invention, it is preferable that the total thickness of the cured film is 5 μm to 100 μm. When the total thickness of the cured film is 5 μm to 100 μm, light emitted from the light-emitting element 2 in all directions can be suppressed from being absorbed in the cured film 3, the light extraction efficiency can be increased, and the luminance can be improved. Furthermore, it becomes possible to suppress wiring defects such as short circuits of wirings due to reduction in the thickness of the display device itself having the light-emitting element and shortening of the wiring distance, suppress reduction in loss, and improve high-speed responsiveness.

[0028] The total thickness of the cured film means the total thickness of the continuous cured film layer in which at least a part of one cured film is in contact with another cured film. For example, when a plurality of cured films 3 are laminated as shown in FIG. 1 described above, the region indicated by 19 in FIG. 1 is the total thickness of the cured film layer. The total thickness is preferably 7 to 70 μm, more preferably 8 to 60 μm. If it is less than 5 μm, the protection of the metal wiring is insufficient, so there is a concern about wiring defects such as short circuits of the wiring. If it exceeds 100 μm, there is a concern about insufficient light extraction efficiency, and it may be inconvenient in terms of suppressing wiring defects such as short circuits of wirings due to reduction in the thickness of the display device itself and shortening of the wiring distance, suppressing reduction in loss, and improving high-speed responsiveness.

[0029] When a plurality of cured films are laminated, the number of layers of the cured film is preferably 2 or more and 10 or less.

[0030] From the viewpoint of arranging a plurality of light-emitting elements, it is preferable that there is at least one layer of the cured film. Furthermore, by having two or more layers, the number of metal wirings connectable to the light-emitting elements can be increased, so that a plurality of light-emitting elements can be arranged. Also, from the viewpoints of suppressing wiring defects such as short circuits of wirings due to reduction in the thickness of the package and shortening of the wiring distance, reduction in loss, and improvement in high-speed responsiveness, 10 layers or less are preferable.

[0031] In the present invention, an opening pattern penetrating in the thickness direction is provided in the cured film, and at least a metal wiring is arranged in the opening pattern. It is preferable that the longest length of the bottom surface portion of the metal wiring formed at the position in contact with the light-emitting element is 2 to 20 μm.

[0032] FIG. 2 shows an enlarged front cross-sectional view (upper part) of the designated area A in FIG. 1 and a bottom view (lower part) excluding the light-emitting element in the designated area A. In the enlarged front cross-sectional view (upper part) of the designated area A in FIG. 2, the cured film 3 is provided on the light-emitting element 2. An opening pattern 12 is provided in the cured film 3, and a diagram showing a metal wiring 4 formed in the opening pattern 12 is shown. The bottom surface portion 13 of the metal wiring 4 shows the form of the metal wiring 4 extending in the cured film 3 up to the position in contact with the light-emitting element 2 and the electrode terminal 6 of the light-emitting element 2.

[0033] In the bottom view (lower part) of the designated area A in FIG. 2 excluding the light-emitting element, it is a view of the bottom surface portion 13 of the metal wiring 4 extending in the cured film 3 with the light-emitting element 2 removed, as seen from below, and shows the bottom surface portion 13. The shape of the bottom surface portion 13 may vary depending on the form of the product or the light-emitting element. In the case of a circular shape, the diameter is defined as the longest length 14. In the case of an elliptical shape, the major axis is defined as the longest length 14. In the case of a polygon such as a rectangle, the longest diagonal line connecting the vertices of the corners is defined as the longest length 14. Note that the bottom surface portion 13 in the bottom view (lower part) of the designated area A in FIG. 2 shows an example of a circular shape.

[0034] With this configuration, a minute light-emitting element can be applied, and high-density mounting of a plurality of light-emitting elements becomes possible, and a display device having a light-emitting element with a wide size and high resolution can be obtained. Furthermore, it becomes possible to form a finer metal wiring, and since the number of wirings that can be formed per unit area increases, the thickness of the entire cured film can be reduced, suppressing the absorption of light emitted from the light-emitting element 2 in all directions in the cured film 3, improving the light extraction efficiency, and improving the luminance. Furthermore, it becomes possible to suppress wiring defects such as short circuits in the wiring due to the reduction in the height of the display device itself having the light-emitting element and the shortening of the wiring distance, suppress the reduction in loss, and improve the high-speed responsiveness.

[0035] From the perspective of applying a small light-emitting element and achieving high-density mounting of the light-emitting element, the maximum length of the bottom surface portion of the metal wiring is preferably 2 to 15 μm, more preferably 2 to 10 μm, and even more preferably 2 to 5 μm. If it is less than 2 μm, connection failure with the light-emitting element 2 may occur, and if it exceeds 20 μm, it may be detrimental to the application of the small light-emitting element and high-density mounting.

[0036] In the present invention, the maximum length of the bottom surface portion of the metal wiring formed at a position close to the light-emitting element may be 2 to 20 μm.

[0037] With this configuration, a small light-emitting element can be applied, and high-density mounting of a plurality of light-emitting elements becomes possible, enabling a display device having a light-emitting element with a wide size and high resolution to be obtained. Furthermore, it becomes possible to form finer metal wiring, and since the number of wirings that can be formed per unit area increases, the thickness of the entire cured film can be reduced, suppressing the absorption of light emitted from the light-emitting element 2 in all directions in the cured film 3, enhancing the light extraction efficiency, and improving the luminance. Furthermore, it becomes possible to suppress wiring defects such as short circuits of the wiring due to the reduction in the height of the display device itself having the light-emitting element and the shortening of the wiring distance, suppress the reduction in loss, and improve the high-speed response performance.

[0038] From the perspective of applying a small light-emitting element and achieving high-density mounting of the light-emitting element, the maximum length of the bottom surface portion of the metal wiring is preferably 2 to 15 μm, more preferably 2 to 10 μm, and even more preferably 2 to 5 μm. If it is less than 2 μm, connection failure with the light-emitting element 2 may occur, and if it exceeds 20 μm, it may be detrimental to the application of the small light-emitting element and high-density mounting.

[0039] The thickness of the cured film is preferably 1.1 times or more and 4.0 times or less the thickness of the metal wiring.

[0040] The thickness of the metal wiring, as described with reference to the front enlarged cross-sectional view (upper part) of the designated area A in FIG. 2, refers to the thickness of the metal wiring 4a disposed on the surface of the cured film 3, and does not include the thickness of the metal wiring 4b extending into the opening pattern penetrating in the thickness direction in the cured film 3. The thickness of the metal wiring is preferably 0.1 to 10 μm, more preferably 3 to 10 μm. By setting the thickness of the metal wiring to 0.1 to 10 μm, it becomes possible to suppress wiring defects such as a reduction in the height of the display device having the light-emitting element and a short circuit of the wiring due to shortening of the wiring distance, suppress a reduction in loss, and improve high-speed responsiveness. Further, by setting it to 3 to 10 μm, the wiring resistance can be reduced, which can contribute to suppression of power consumption and improvement of luminance.

[0041] The thickness of the cured film, as described with reference to the front enlarged cross-sectional view (upper part) of the designated area A in FIG. 2, refers to the thickness of the cured film 3a covering the metal wiring 4a.

[0042] Thereby, it also acts as a protective film for the appropriate metal wiring, and a cured film excellent in reliability that suppresses wiring defects such as a short circuit of the wiring can be obtained.

[0043] The thickness of the metal wiring may be the same or different for each layer. When they are different, as an example, in FIG. 1, it is preferable that the thickness of the metal wiring closer to the bump 10 is thicker than the thickness of the metal wiring closer to the light-emitting element 2. Thereby, wiring defects can be suppressed when connecting the light-emitting element driving substrate 7 using the bump 10, and a highly reliable display device can be obtained.

[0044] In the present invention, it is preferable that the cured film has a configuration covering a surface other than the light extraction surface of the light-emitting element.

[0045] As an example, FIG. 3 shows an upper enlarged cross-sectional view (upper part) of the designated area B in FIG. 1, a cross-sectional view (middle part) excluding the wiring on the plane orthogonal to the front of the designated area B, and a bottom view (lower part) excluding the opposing substrate of the designated area B.

[0046] In the enlarged cross-sectional view (upper part) of the upper surface of the designated area B in FIG. 3, the light-emitting element 2 is covered with the cured film 3, and the metal wiring 4 that is connected to the electrode terminal 6 of the light-emitting element and extends in the cured film 3 is shown from the upper surface.

[0047] In the cross-sectional view (middle part) excluding the wiring on the plane orthogonal to the front surface of FIG. 3, it is shown that the periphery of the light-emitting element 2 is covered with the cured film 3.

[0048] In the bottom view (lower part) excluding the counter substrate of the designated area B in FIG. 3, although the periphery of the light-emitting element 2 is covered with the cured film 3, it shows that one surface of the light-emitting element 2 is not covered with the cured film 3.

[0049] As shown in FIGS. 1 and 3, by covering all the side surfaces and the upper surface part of the light-emitting element 2 with the cured film 3, the light-emitting element 2 can be protected from external impacts. In addition, the step generated by the arrangement of the light-emitting element 2 can be flattened, and it is preferable because the bonding with the counter substrate 5 becomes easy.

[0050] The cured film 3 that covers the surfaces other than the light extraction surface of the light-emitting element 2 has the above-described transmittance, so that the absorption of the light emitted from the light-emitting element 2 in the direction of the cured film 3 is suppressed, the light extraction efficiency can be increased, and the luminance can be improved. From the viewpoint of luminance improvement, it is more preferable that the transmittance of the cured film 3 is 90% or more and 100% or less.

[0051] In the present invention, it is preferable to provide a reflective film on the cured film.

[0052] As shown in FIG. 4, a reflective film 15 is provided on the cured film 3 arranged around the light-emitting element 2. By providing the reflective film 15 on the cured film 3 having the above-described high light transmittance property, the light that has passed through the cured film 3 is reflected by the reflective film 15, so that the extraction efficiency is further increased and the luminance can be improved.

[0053] The reflective film can be provided at any position of the cured film, and can be arranged in a manner that surrounds the four sides with respect to the extraction direction of the light-emitting element, or arranged obliquely with respect to the light-emitting element, or arranged with a curvature. The reflective film may be any film that reflects light, and examples include, but are not limited to, aluminum, silver, copper, titanium, and alloys containing them.

[0054] In the present invention, it is preferable to have a partition wall having a thickness equal to or greater than the thickness of the light-emitting element between a plurality of the light-emitting elements.

[0055] As shown in FIG. 5, it is preferable to have a repeating pattern corresponding to the number of pixels of the display device 1 having the light-emitting element 2, that is, a partition wall 16 between or around each light-emitting element 2. This configuration is preferable because it facilitates bonding with the counter substrate 5.

[0056] The thickness of the partition wall is preferably greater than the thickness of each light-emitting element, and specifically, 5 μm to 120 μm is preferable.

[0057] The partition wall may be composed of a cured film obtained by curing a resin composition containing (A) resin, or may be composed of a material other than the resin composition containing (A) resin, and known materials such as epoxy resin, (meth)acrylic polymer, polyurethane, polyester, polyolefin, and polysiloxane may be used. By using these materials, a partition wall with excellent adhesion can be formed.

[0058] In order to suppress light leakage from the light-emitting element and color mixing between each pixel and improve the contrast, a light-shielding portion may be provided on the side surface of the partition wall or on the partition wall itself. The light-shielding portion is a portion containing, for example, a black pigment. Furthermore, in order to reflect the light emitted from the light-emitting element in the direction of the partition wall and increase the light extraction efficiency and improve the luminance, a reflecting portion may be provided on the side surface of the partition wall. The reflecting portion is a portion containing, for example, a white pigment.

[0059] It is preferable to dispose a partition wall having a thickness equal to or greater than the thickness of the light-emitting element between the plurality of light-emitting elements in the cured film covering the light-emitting element.

[0060] As another embodiment of providing a partition wall, as shown in FIG. 6, a configuration is illustrated in which a partition wall 16 is provided between or around the light-emitting elements 2 in the cured film 3 covering the light-emitting element 2.

[0061] The partition wall shown in FIG. 6 may be composed of a material other than a resin composition containing a resin, and known materials such as epoxy resin, (meth)acrylic polymer, polyurethane, polyester, polyolefin, and polysiloxane may be used. By using these materials, a partition wall with excellent adhesion can be formed.

[0062] By disposing the partition wall, it can be used as a mark when transferring the subsequent light-emitting element, and since it can also be used as a photo spacer, the efficiency during light-emitting element transfer can be increased, which is preferable. Furthermore, in order to suppress light leakage from the light-emitting element and color mixing between pixels and improve contrast, a light-shielding portion may be provided on the side surface of the partition wall or on the partition wall itself. The light-shielding portion is a portion containing, for example, a black pigment.

[0063] In the present invention, it is also preferable to adopt a configuration in which a partition wall having a thickness equal to or greater than the thickness of the light-emitting element is disposed between the plurality of light-emitting elements and a reflective film is provided around the partition wall.

[0064] Specifically, as shown in FIGS. 7 and 8, a configuration of a display device in which a partition wall 16 having a thickness equal to or greater than the thickness of the light-emitting element 2 is disposed between the plurality of light-emitting elements 2 and a reflective film 15 is provided around the partition wall can be cited.

[0065] By adopting a configuration in which a reflective film is provided around the partition wall, the light emitted from the light-emitting element is reflected by the reflective film around the partition wall, thereby increasing the light extraction efficiency and improving the luminance.

[0066] In order to suppress light leakage from the light-emitting element and color mixing between pixels and improve contrast, a light-shielding portion may be provided on the side surface of the partition wall or on the partition wall itself. The light-shielding portion is a portion containing, for example, a black pigment. Furthermore, in order to reflect the light emitted from the light-emitting element in the direction of the partition wall and increase the light extraction efficiency, and improve the luminance, a reflecting portion may be provided on the side surface of the partition wall. The reflecting portion is a portion containing, for example, a white pigment.

[0067] In the present invention, a light-diffusing layer may be provided around the light-emitting element, the cured film, or the metal wiring.

[0068] In the present invention, it is preferable that the light-emitting element is an LED having a side length of 5 μm or more and 700 μm or less, and it is more preferable that the light-emitting element is an LED having a side length of 5 μm or more and 100 μm or less.

[0069] An LED is composed of a PN junction in which a P-type semiconductor and an N-type semiconductor are joined. When a forward voltage is applied to the LED, electrons and holes move in the chip and a current flows. At this time, an energy difference is generated by the combination of electrons and holes, and the surplus energy is converted into light energy and emits light. The wavelength of the light emitted from the LED varies depending on the compound constituting the semiconductor such as GaN, GaAs, InGaAlP, and GaP, and this difference in wavelength determines the emission color. Also, white is generally displayed by mixing two or more different colors of light. In the case of an LED, the color reproducibility is significantly improved by mixing the three primary colors of red, green, and blue, and it is possible to display a more natural white.

[0070] Examples of the shape of the LED include a bullet type, a chip type, and a polyhedron type. From the viewpoint of miniaturization of the LED, the chip type and the polygon type are preferable. Also, it is preferable that the side length of the LED is 5 μm or more and 700 μm or less because a plurality of chips can be arranged, and it is more preferable that the side length of the LED is 5 μm or more and 100 μm or less.

[0071] Regarding the method of mounting on a substrate such as a light-emitting element driving substrate 7 provided with a cured film 3 of an LED, for example, a pick-and-place method, a mass transfer method, etc. have been proposed, but it is not limited thereto.

[0072] Regarding the mounting of an LED on a substrate, for example, there are a method of arranging and mounting LEDs that emit red, green, and blue light at predetermined positions on the substrate in a matrix, and a method of arranging and mounting a single type of LED such as an LED that emits red or blue light or an ultraviolet LED that emits ultraviolet light on the substrate. For the former method, LEDs that emit red, green, and blue light respectively may be used, or those in which LEDs that emit red, green, and blue light are stacked in the vertical direction may be used. The latter method can facilitate the array mounting of the LEDs. In this case, wavelength conversion materials such as quantum dots can be utilized to create red, green, and blue sub-pixels for full-color display.

[0073] Known materials can be used as the wavelength conversion material.

[0074] For example, when using an LED that emits blue light, first, an LED array substrate on which only LEDs that emit blue light are arranged and mounted is fabricated, and then it is preferable to arrange a wavelength conversion layer that is excited by blue light and wavelength-converted to emit red or green light at positions corresponding to red and green sub-pixels. Thereby, it becomes possible to form red, green, and blue sub-pixels using only LEDs that emit blue light.

[0075] On the other hand, when using an ultraviolet LED that emits ultraviolet light, first, an LED array substrate on which only ultraviolet LEDs are arranged and mounted is fabricated, and then it is preferable to arrange a wavelength conversion layer that is excited by ultraviolet light and wavelength-converted to emit red, green, and blue light at positions corresponding to red, green, and blue sub-pixels. Thereby, the difference in the radiation angle of light due to the color of the sub-pixels described above can be suppressed.

[0076] Known materials can be used as the wavelength conversion layer, and a color filter or the like may be used as necessary.

[0077] Examples of the counter substrate in the present invention include a glass plate, a resin plate, a resin film, etc. As the material of the glass plate, non-alkali glass is preferable. As the materials of the resin plate and the resin film, polyester, (meth)acrylic polymer, transparent polyimide, polyethersulfone, etc. are preferable. The thickness of the glass plate and the resin plate is preferably 1 mm or less, more preferably 0.8 mm or less. The thickness of the resin film is preferably 100 μm or less.

[0078] In the present invention, it is preferable that the display device includes a driving element, and the light-emitting element is electrically connected through the driving element and a metal wiring extending in the cured film. Since the display device includes a driving element and the light-emitting element is electrically connected through the driving element and a metal wiring extending in the cured film, a plurality of light-emitting elements can be individually switched and driven. Examples of the driving element include a driver IC, etc., and a plurality of driver ICs may be used for one LED or one unit of LEDs consisting of red, blue, and green according to functions.

[0079] As a configuration mode of the arrangement of the driving element, as shown in FIG. 9, a configuration in which the driving element 8 is arranged in the cured film 3 on the counter substrate 5 near the light-emitting element 2 is preferable. Also, as shown in FIG. 10, a configuration in which the driving element 8 is arranged in the cured film at a position above the light-emitting element 2 is also preferable.

[0080] This makes it possible to suppress wiring defects such as short circuits of the wiring due to shortening of the wiring distance, suppress reduction of loss, and improve high-speed responsiveness.

[0081] In the present invention, it is further preferable to have a driving element and a substrate, wherein the driving element is connected to a light-emitting element through a metal wiring, and at least a part of the metal wiring extends on a side surface of the substrate. By having a driving element and a substrate, with the driving element connected to a light-emitting element through a metal wiring and at least a part of the metal wiring extending on the side surface of the substrate, a plurality of light-emitting elements can be individually driven by switching, the thickness of the display device itself can be reduced, the high-speed response performance can be improved, and the display device can be made smaller and have a narrower bezel.

[0082] The substrate is not particularly limited as long as it is the same as the light-emitting element driving substrate 7, and known substrates can be used. For example, a glass substrate, a sapphire substrate, a printed wiring board, a TFT array substrate, ceramics, etc. can be mentioned. The metal wiring that extends at least partially on the side surface of the substrate can be made of, for example, gold, silver, copper, aluminum, nickel, titanium, tungsten, aluminum, tin, chromium, or an alloy containing these. Also, the metal wiring that extends on the side surface of the substrate can be formed by, for example, wet plating such as electroless plating or electrolytic plating, CVD chemical vapor deposition (CVD) methods such as thermal CVD, plasma CVD, or laser CVD, dry plating methods such as vacuum evaporation, sputtering, or ion plating, or a method of bonding a metal foil to the substrate and then performing etching. Also, grooves may be arranged on the side surface of the substrate. In this case, since the adjacent metal wirings are surely separated by the grooves, a short circuit between the metal wirings can be suppressed. The grooves for arranging the side conductor lines can be formed by a cutting process method, an etching method, a laser processing method, etc.

[0083] As a configuration mode of the metal wiring, a configuration arranged as shown in FIG. 1 or 4c of FIG. 5 is preferable, for example.

[0084] In the present invention, the metal wiring may be a conductive film.

[0085] Examples of the conductive film include compounds mainly containing oxides of at least one element such as indium, gallium, zinc, tin, titanium, and niobium, organic substances, and photosensitive conductive pastes containing conductive particles. Other known materials may also be used.

[0086] Specific examples of the compounds mainly containing oxides of at least one element such as indium, gallium, zinc, tin, titanium, and niobium include indium tin zinc oxide (ITZO), indium gallium zinc oxide (IGZO: InGaZnO), zinc oxide (ZnO), indium zinc oxide (IZO), indium gallium oxide (IGO), indium tin oxide (ITO), and indium oxide (InO).

[0087] These conductive films can be formed by, for example, wet plating such as electroless plating and electrolytic plating, CVD chemical vapor deposition methods (CVD) such as thermal CVD, plasma CVD, and laser CVD, dry plating methods such as vacuum evaporation, sputtering, and ion plating, and a method of bonding a metal foil to a substrate and then performing etching.

[0088] In the photosensitive conductive paste containing organic substances and conductive particles, the content of the conductive particles is preferably 60 to 90% by mass. When the conductive layer contains organic substances, disconnection can be suppressed at curved surfaces and bent portions, and conductivity can be improved. When the content of the conductive particles is less than 60% by mass, the contact probability between the conductive particles decreases, and the conductivity decreases. Also, at the bent portions of the wiring, the conductive particles are likely to separate from each other. The content of the conductive particles is preferably 70% by mass or more. On the other hand, when the content of the conductive particles exceeds 90% by mass, it becomes difficult to form a wiring pattern, and disconnection is likely to occur at the bent portions. The content of the conductive particles is preferably 80% by mass or less.

[0089] Examples of the organic substance include epoxy resins, phenoxy resins, acrylic copolymers, epoxy carboxylate compounds, etc. Two or more of these may be contained. Also, an organic substance having a urethane bond may be contained. By containing an organic substance having a urethane bond, the flexibility of the wiring can be improved. Further, the organic substance preferably exhibits photosensitivity, and a fine wiring pattern can be easily formed by photolithography. The photosensitivity is expressed, for example, by containing a photoinitiator and a component having an unsaturated double bond.

[0090] The conductive particles in the present invention refer to particles composed of a substance having an electrical resistivity of 10 -5 Ω·m or less. Examples of the material constituting the conductive particles include silver, gold, copper, platinum, lead, tin, nickel, aluminum, tungsten, molybdenum, chromium, titanium, indium, alloys of these metals, and carbon particles. Also, it is preferable to contain two or more kinds of conductive particles. By containing two or more kinds of conductive particles, in the heat treatment step described later, sintering and volume shrinkage between the same kind of conductive particles are suppressed, and as a result, volume shrinkage of the entire conductive film is suppressed, and flexibility can be improved.

[0091] The average particle diameter of the conductive particles is preferably 0.005 to 2 μm. The average particle diameter here means the average particle diameter of the large-diameter particles when two or more kinds of conductive particles are contained. When the average particle diameter of the conductive particles is 0.005 μm or more, the interaction between the conductive particles can be moderately suppressed, and the dispersion state of the conductive particles can be maintained more stably. The average particle diameter of the conductive particles is more preferably 0.01 μm or more. On the other hand, when the average particle diameter of the conductive particles is 2 μm or less, it becomes easier to form a desired wiring pattern. The average particle diameter of the conductive particles is more preferably 1.5 μm or less.

[0092] The thickness of the conductive film is preferably 2 to 10 μm. When the thickness of the conductive film is 2 μm or more, disconnection at the bent portion can be further suppressed, and the conductivity can be further improved. The thickness of the conductive film is more preferably 4 μm or more. On the other hand, when the thickness of the conductive film is 10 μm or less, the wiring pattern can be formed more easily in the manufacturing process. The thickness of the conductive film is more preferably 8 μm or less.

[0093] As a configuration mode of the conductive film, for example, a configuration arranged as shown in 27 of FIGS. 18 to 21 is preferable.

[0094] In the present invention, it is further preferable to have a light-shielding layer between a plurality of light-emitting elements. By having a light-shielding layer between a plurality of light-emitting elements, light leakage from the light-emitting elements and color mixing between pixels can be suppressed without significantly impairing the light extraction efficiency, and the contrast can be improved.

[0095] The light-shielding layer may be composed of a cured film obtained by curing a resin composition containing (A) a resin and (E) a colorant, or may be composed of a material other than the resin composition containing (A) a resin. Known materials such as epoxy resins, (meth)acrylic polymers, polyurethanes, polyesters, polyolefins, and polysiloxanes may be used. As the (E) colorant, a black pigment may be used. For example, black organic pigments such as carbon black, perylene black, and aniline black, graphite, and metal fine particles, metal oxides, composite oxides, metal sulfides, metal nitrides, metal oxynitrides, etc. of titanium, copper, iron, manganese, cobalt, chromium, nickel, zinc, calcium, silver, etc. inorganic pigments. Also, a red pigment, a blue pigment, and if necessary, a yellow pigment and other pigments may be combined to form black. Dyes may also be used. Two or more colorants may be contained.

[0096] Sensitivity may be imparted to the resin composition containing (A) a resin and (E) a colorant, or the (B) photosensitizer described later may be used.

[0097] As a method for manufacturing a resin composition containing (A) resin and (E) colorant, for example, a resin solution containing (A) resin, (E) colorant, a dispersant and an organic solvent as required is dispersed using a disperser to prepare a colorant dispersion liquid with a high colorant concentration, and then (A) resin and other components such as a photosensitizer as required are added and stirred. Filtration may be performed as required.

[0098] Examples of the disperser include a ball mill, a bead mill, a sand grinder, a three-roll mill, a high-speed impact mill, etc. Among these, a bead mill is preferable for improving dispersion efficiency and achieving fine dispersion. Examples of the bead mill include a coball mill, a basket mill, a pin mill, a dyno mill, etc. Examples of the beads used in the bead mill include titania beads, zirconia beads, and zircon beads. The bead diameter of the bead mill is preferably 0.03 to 1.0 mm. When the primary particle diameter of the (E) colorant and the particle diameter of the secondary particles formed by aggregation of the primary particles are small, it is preferable to use fine beads with a diameter of 0.03 to 0.10 mm. In this case, a bead mill equipped with a separator using a centrifugal separation method, which can separate the fine beads and the dispersion liquid, is preferable. On the other hand, when dispersing a colorant containing coarse particles of about submicron size, it is preferable to use beads with a diameter of 0.10 mm or more in order to obtain sufficient grinding force.

[0099] The resin composition containing (A) resin and (E) colorant can be applied to various substrates, dried, and then a light-shielding layer can be obtained by heat treatment. When it has photosensitivity, a patterned light-shielding layer can be obtained by irradiating actinic rays described below for exposure and then performing development and heat treatment described below.

[0100] The thickness of the light-shielding layer is preferably 0.1 to 5 μm. When the thickness of the light-shielding layer is 0.1 μm or more, light leakage from the light-emitting element and color mixing between pixels can be suppressed, and the contrast can be improved. The thickness of the light-shielding layer is more preferably 0.5 μm or more. On the other hand, when the thickness of the wiring is 5 μm or less, light leakage from the light-emitting element and color mixing between pixels can be suppressed without significantly impairing the light extraction efficiency, and the contrast can be improved. The thickness of the light-shielding layer is more preferably 4 μm or less.

[0101] For the light-shielding layer, a colored film is formed on an alkali-free glass with a thickness of 0.7 mm so that the film thickness becomes 1.0 μm, and it is preferable that the reflection chromaticity values (a*, b*) measured from the glass surface satisfy -0.5 ≤ a* ≤ 1.0 and -1.0 ≤ b* ≤ 0.5, and more preferably -0.5 ≤ a* ≤ 0.5 and -1.0 ≤ b* ≤ 0.4. The reflection chromaticity is an index of the color tone of the image reflected in the colored film. The closer (a*, b*) is to (0.0, 0.0), the more achromatic the reflected color tone can be said to be. On the other hand, for the black display of a liquid crystal display device or an organic EL display, the reflection color tone generally has a negative value for b*, and has a bluish color tone. Therefore, for the decorative film used in the display device, it is preferable that b* has a negative value.

[0102] The reflection chromaticity (L*, a*, b*) of the colored film is obtained by measuring the specular reflection chromaticity (SCI) with respect to the light incident from the transparent substrate under the measurement conditions of a standard light source D65 (color temperature 6504K), a viewing angle of 2° (CIE1976), atmospheric pressure, and 20°C, using a spectrocolorimeter (CM-2600d; manufactured by Konica Minolta, Inc.) calibrated with a white calibration plate (CM-A145; manufactured by Konica Minolta, Inc.).

[0103] As a configuration mode of the light-shielding layer, for example, a configuration arranged as shown in 28 of FIG. 22 is preferable. The light-shielding layer 28 may be in contact with or separated from the light-emitting element 2.

[0104] In the present invention, for a cured film obtained by curing a resin composition containing (A) resin, the light transmittance at a wavelength of 450 nm based on a thickness of 5 μm is 80% or more and 100% or less. As a result, it is possible to suppress the light emitted from the light-emitting element in all directions from being absorbed in the cured film obtained by curing the resin composition containing (A) resin, improve the light extraction efficiency, and improve the luminance.

[0105] In order to obtain such characteristics, the (A) resin preferably has high heat resistance. Specifically, there is little resin deterioration at a high temperature of 160 °C or higher during or after the heat treatment, and there is little formation of, for example, a quinone structure which is one of the coloring structures associated with resin deterioration or resin decomposition. Further, such a cured film is preferable because the outgassing amount is reduced, which is one of the excellent characteristics as a cured film used as a display device, such as an insulating film, a protective film, and a partition wall.

[0106] Further, from the viewpoint of forming a desired opening pattern by exposure and development, the (A) resin preferably has a high light transmittance at the exposure wavelength before curing. In order to obtain such characteristics, for example, it is preferable to shorten the conjugated chain derived from the aromatic ring of the resin or reduce the charge transfer within or between molecules.

[0107] Furthermore, for the protection of the metal wiring, it is preferable that the processability is excellent even for a thick film having a thickness of 10 μm or more.

[0108] (A) The resin is not particularly limited, but is preferably an alkali-soluble resin from the viewpoint of reducing the environmental load. Alkali solubility means that a solution obtained by dissolving the resin in γ-butyrolactone is applied onto a silicon wafer, pre-baked at 120 °C for 4 minutes to form a pre-baked film having a film thickness of 10 μm ± 0.5 μm. Next, the pre-baked film is immersed in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 23 ± 1 °C for 1 minute, and then the film thickness reduction when rinsed with pure water is determined. A resin is defined as alkali-soluble if the dissolution rate of the pre-baked film is 50 nm / min or more.

[0109] The resin (A) preferably contains one or more resins selected from the group consisting of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, and copolymers thereof. The resin (A) may contain these resins alone or in combination of a plurality of resins.

[0110] Polyimide, polyimide precursor, polybenzoxazole, and polybenzoxazole precursor will be described. The polyimide is not particularly limited as long as it has an imide ring. The polyimide precursor is not particularly limited as long as it has a structure that becomes a polyimide having an imide ring by dehydration ring closure, and can contain polyamic acid, polyamic acid ester, etc. The polybenzoxazole is not particularly limited as long as it has an oxazole ring. The polybenzoxazole precursor is not particularly limited as long as it has a structure that becomes a polybenzoxazole having a benzoxazole ring by dehydration ring closure, and can contain polyhydroxyamide, etc.

[0111] The polyimide has a structural unit represented by the general formula (1), the polyimide precursor and the polybenzoxazole precursor have a structural unit represented by the following general formula (2), and the polybenzoxazole has a structural unit represented by the general formula (3). Two or more of these may be contained, or a resin obtained by copolymerizing the structural unit represented by the general formula (1), the structural unit represented by the general formula (2), and the structural unit represented by the general formula (3) may be contained.

[0112]

Chemical formula

[0113] In the general formula (1), V represents a 4- to 10-valent organic group having 4 to 40 carbon atoms, and W represents a 2- to 8-valent organic group having 4 to 40 carbon atoms. a and b each represent an integer of 0 to 6. R 1 and R 2represents a group selected from the group consisting of a hydroxyl group, a carboxy group, a sulfonic acid group, and a thiol group, and a plurality of Rs 1 and R 2 may be the same or different from each other.

[0114] [Chemical formula]

[0115] In General Formula (2), X and Y each independently represent a divalent to octavalent organic group having 4 to 40 carbon atoms. R 3 and R 4 each independently represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. c and d each represent an integer of 0 to 4, and e and f each represent an integer of 0 to 2.

[0116] [Chemical formula]

[0117] In General Formula (3), T and U each independently represent a divalent to octavalent organic group having 4 to 40 carbon atoms.

[0118] (A) In order to make the resin alkali-soluble, it is preferable that a + b > 0 in General Formula (1). Also, it is preferable that c + d + e + f > 0 in General Formula (2). In General Formula (2), in the case of a polyimide precursor, it is preferable that X and Y in General Formula (2) have an aromatic group. Further, X in General Formula (2) has an aromatic group, e > 2, and has a carboxy group or a carboxyester group at the ortho position of the aromatic amide group, and has a structure that forms an imide ring by dehydration cyclization.

[0119] Also, in General Formula (2), in the case of a polybenzoxazole precursor, X in General Formula (2) has an aromatic group, d > 0, and has a hydroxyl group at the ortho position of the aromatic amide group, and has a structure that forms a benzoxazole ring by dehydration cyclization.

[0120] (A) In the resin, the repeating number n of the structural unit represented by the general formula (1), general formula (2) or general formula (3) is preferably 5 to 100,000, more preferably 10 to 100,000.

[0121] In addition, the (A) resin may have other structural units in addition to the structural unit represented by the general formula (1), general formula (2) or general formula (3). Examples of the other structural units include, but are not limited to, a cardo structure, a siloxane structure, etc. In this case, it is preferable that the structural unit represented by the general formula (1) or general formula (2) be the main constituent unit. Here, the main constituent unit means having 50 mol% or more of the structural unit represented by the general formula (1), general formula (2) or general formula (3) among all the structural units, and more preferably having 70 mol% or more.

[0122] In the above general formula (1), V-(R 1 ) a , in the above general formula (2), (OH) c -X-(COOR 3 ) e and T in the above general formula (3) represent the residue of an acid. V is a tetravalent to decavalent organic group having 4 to 40 carbon atoms, and among them, an organic group having 4 to 40 carbon atoms containing an aromatic ring or a cycloaliphatic group is preferable. X and T are divalent to octavalent organic groups having 4 to 40 carbon atoms, and among them, an organic group having 4 to 40 carbon atoms containing an aromatic ring or an aliphatic group is preferable.

[0123] Examples of the acid components constituting the acid residue include, as dicarboxylic acids, terephthalic acid, isophthalic acid, diphenyl ether dicarboxylic acid, bis(carboxyphenyl)hexafluoropropane, biphenyl dicarboxylic acid, benzophenone dicarboxylic acid, triphenyl dicarboxylic acid, suberic acid, dodecafluorosuberic acid, azelaic acid, sebacic acid, hexadecafluorosebacic acid, 1,9-nonanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, eicosanedioic acid, heneicosanedioic acid, docosanedioic acid, tricosanedioic acid, tetracosanedioic acid, pentacosanedioic acid, hexacosanedioic acid, heptacosanedioic acid, octacosanedioic acid, nonacosanedioic acid, triacontanedioic acid, etc.; as tricarboxylic acids, trimellitic acid, trimesic acid, diphenyl ether tricarboxylic acid, biphenyl tricarboxylic acid, etc.; as tetracarboxylic acids, pyromellitic acid, 3,3’,4,4’-biphenyltetracarboxylic acid, 2,3,3’,4’-biphenyltetracarboxylic acid, 2,2’,3,3’-biphenyltetracarboxylic acid, 3,3’,4,4’-diphenyl ether tetracarboxylic acid, 3,3’,4,4’-benzophenone tetracarboxylic acid, 2,2’,3,3’-benzophenone tetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2-bis(2,3-dicarboxyphenyl)propane, 1,1-bis(3,4-dicarboxyphenyl)ethane, 1,1-bis(2,3-dicarboxyphenyl)ethane, bis(3,4-dicarboxyphenyl)methane, bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)ether, 1,2,5,6-naphthalenetetracarboxylic acid, 9,9-bis(3,4-dicarboxyphenyl)fluorene, 9,9-bis{4-(3,4-dicarboxyphenoxy)phenyl}fluorene, 2,3,6,7-naphthalenetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 2,3,5,6-pyridinetetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane and aromatic tetracarboxylic acids, butanetetracarboxylic acids, cyclobutanetetracarboxylic acids, 1,2,3,4-cyclopentanetetracarboxylic acids, etc. having the structures shown below can be mentioned, but are not limited thereto. Two or more of these may be used.,

[0124] [Chemical formula]

[0125] In the formula, R 17 represents an oxygen atom, C(CF3)2, or C(CH3)2. R 18 and R 19 represent a hydrogen atom or a hydroxyl group.,

[0126] These acids can be used as they are, or as acid anhydrides, halides, or active esters.,

[0127] W-(R 2 ) b in the general formula (1) above, (OH) d -Y-(COOR 4 ) f in the general formula (2) above, and U in the general formula (3) above represent residues of diamines. W, Y, and U are organic groups having 2 to 8 valences and 4 to 40 carbon atoms, and among them, organic groups having 4 to 40 carbon atoms containing an aromatic ring or a cycloaliphatic group are preferable.,

[0128] Specific examples of the diamine constituting the diamine residue include hydroxyl group-containing diamines such as bis(3-amino-4-hydroxyphenyl)hexafluoropropane, bis(3-amino-4-hydroxyphenyl)sulfone, bis(3-amino-4-hydroxyphenyl)propane, bis(3-amino-4-hydroxyphenyl)methylene, bis(3-amino-4-hydroxyphenyl)ether, bis(3-amino-4-hydroxy)biphenyl, bis(3-amino-4-hydroxyphenyl)fluorene; sulfonic acid-containing diamines such as 3-sulfonic acid-4,4'-diaminodiphenyl ether; thiol group-containing diamines such as dimercaptophenylenediamine; 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfide, 1,4-bis(4-aminophenoxy)benzene, benzidine, m-phenylenediamine, p-phenylenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, bis(4-aminophenoxyphenyl)sulfone, bis(3-aminophenoxyphenyl)sulfone, bis(4-aminophenoxy)biphenyl, bis{4-(4-aminophenoxy)phenyl}ether, 1,4-bis(4-aminophenoxy)benzene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diethyl-4,4'-diaminobiphenyl, 2,2',3,3'-tetramethyl-4,4'-diaminobiphenyl, 3,3',4,4'-tetramethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl and other aromatic diamines, and compounds in which some of the hydrogen atoms of these aromatic rings are substituted with an alkyl group having 1 to 10 carbon atoms, a fluoroalkyl group, a halogen atom, etc.; 2,4-diamino-1,3,5-triazine (guanamine), 2,4-diamino-6-methyl-1,3,5-triazine (acetoguanamine), 2,4-diamino-6-phenyl-1,Diamines having a nitrogen-containing heteroaromatic ring such as 3,5-triazine (benzoguanamine), 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(p-aminophenyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(p-aminophenethyl)-1,1,3,3-tetramethyldisiloxane, silicone diamines such as 1,7-bis(p-aminophenyl)-1,1,3,3,5,5,7,7-octamethyltetrasiloxane, alicyclic diamines such as cyclohexyldiamine and methylenebiscyclohexylamine, and diamines having the structure shown below can be mentioned. Two or more of these may be used.,

[0129] [Chemical formula]

[0130] In the formula, R 20 represents an oxygen atom, C(CF3)2, or C(CH3)2. R 21 ~R 24 each independently represents a hydrogen atom or a hydroxyl group.,

[0131] Among them, from the viewpoints of alkali developability and improving the transmittance of the (A) resin and its cured film, it is preferable to contain at least one or more diamines having the structure shown below.,

[0132] [Chemical formula]

[0133] In the formula, R 20 represents an oxygen atom, C(CF3)2, or C(CH3)2. R 21 ~R 22 each independently represents a hydrogen atom or a hydroxyl group.,

[0134] These diamines can be used as diamines, or as diisocyanate compounds or trimethylsilylated diamines obtained by reacting diamines with phosgene.,

[0135] Further, the (A) resin preferably contains a group selected from an alkylene group and an alkylene ether group. These groups may contain an aliphatic ring. As the group selected from an alkylene group and an alkylene ether group, a group represented by the general formula (4) is particularly preferable.

[0136]

Chemical formula

[0137] In the general formula (4), R 5 ~R 8 each independently represents an alkylene group having 1 to 6 carbon atoms. R 9 ~R 16 each independently represents a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 6 carbon atoms. However, the structures represented in the parentheses are different from each other. g, h, and i each independently represent an integer of 0 to 35, and g + h + i > 0.

[0138] Examples of the group represented by the general formula (4) include an ethylene oxide group, a propylene oxide group, and a butylene oxide group, and any of linear, branched, and cyclic forms may be used.

[0139] When the (A) resin has a group selected from an alkylene group and an alkylene ether group, the mechanical properties, particularly the elongation, of the (A) resin and its cured film can be improved, and further, the light transmittance at 450 nm before and after curing can be improved.

[0140] The (A) resin preferably contains a group selected from the alkylene group and the alkylene ether group in W in the general formula (1) or Y in the general formula (2). Thereby, the mechanical properties, particularly the elongation, of the (A) resin and its cured film can be improved, and further, the light transmittance at 450 nm before and after curing can be improved. At the same time, high chemical resistance due to promotion of ring closure in low-temperature heat treatment of the cured film of the resin composition, high adhesion to the substrate metal, and resistance to a highly accelerated stress test (HAST) can be obtained.

[0141] Specific examples of the diamine containing a group selected from an alkylene group and an alkylene ether group include ethylenediamine, 1,3-diaminopropane, 2-methyl-1,3-propanediamine, 1,4-diaminobutane, 1,5-diaminopentane, 2-methyl-1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-methylenebis(cyclohexylamine), 4,4'-methylenebis(2-methylcyclohexylamine), KH-511, ED-600, ED-900, ED-2003, EDR-148, EDR-176, D-200, D-400, D-2000, THF-100, THF-140, THF-170, RE-600, RE-900, RE-2000, RP-405, RP-409, RP-2005, RP-2009, RT-1000, HE-1000, HT-1100, HT-1700, (the above are trade names, manufactured by HUNTSMAN Co., Ltd.), etc.

[0142] Moreover, these diamines may contain bonds such as -S-, -SO-, -SO2-, -NH-, -NCH3-, -N(CH2CH3)-, -N(CH2CH2CH3)-, -N(CH(CH3)2)-, -COO-, -CONH-, -OCONH-, -NHCONH-.

[0143] The diamine residue containing a group selected from an alkylene group and an alkylene ether group is preferably contained in an amount of 5 mol% or more, more preferably 10 mol% or more, based on all the diamine residues. Further, it is preferably contained in an amount of 40 mol% or less, more preferably 30 mol% or less, based on all the diamine residues. By setting the above range, the developability in an alkaline developer can be enhanced, the mechanical properties of the (A) resin and its cured film, particularly the elongation, can be improved, the light transmittance at 450 nm after curing can be improved, and high chemical resistance due to promotion of ring closure by low-temperature heat treatment in the cured film of the resin composition, high adhesion to the metal surface, and resistance to the highly accelerated stress test (HAST) can be obtained.

[0144] Within a range not reducing the heat resistance, a diamine residue having an aliphatic polysiloxane structure may be copolymerized. By copolymerizing a diamine residue having an aliphatic polysiloxane structure, the adhesion to a substrate can be improved. Specifically, examples include those obtained by copolymerizing 1 to 15 mol% of bis(3-aminopropyl)tetramethyldisiloxane, bis(p-aminophenyl)octamethylpentasiloxane, etc. as the diamine component based on all the diamine residues. Copolymerizing within this range is preferable in terms of improving the adhesion to a substrate such as a silicon wafer and not reducing the solubility in an alkaline solution.

[0145] By terminating the (A) resin with a monoamine, acid anhydride, acid chloride, or monocarboxylic acid having an acidic group, a resin having an acidic group at the main chain terminal can be obtained. Known monoamines, acid anhydrides, acid chlorides, monocarboxylic acids may be used, or a plurality of them may be used.

[0146] The content of the above terminal capping agents such as the monoamine, acid anhydride, acid chloride, and monocarboxylic acid is preferably 2 to 25 mol% based on 100 mol% of the total of the acid component and the amine component constituting the (A) resin.

[0147] (A) The resin preferably has a weight average molecular weight of 10,000 or more and 100,000 or less. If the weight average molecular weight is 10,000 or more, the mechanical properties of the cured film after curing can be improved. More preferably, the weight average molecular weight is 20,000 or more. On the other hand, if the weight average molecular weight is 100,000 or less, the developability with various developers can be improved, and further, if the weight average molecular weight is 50,000 or less, the developability with an alkaline solution can be improved, which is preferable.

[0148] The weight average molecular weight (Mw) can be confirmed using GPC (gel permeation chromatography). For example, it can be measured using N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) as the eluent and determined in terms of polystyrene.

[0149] (A) The content of the resin is preferably 3 to 55% by mass, more preferably 5 to 40% by mass, based on 100% by mass of all the components including the solvent. By setting the content within the above range, an appropriate viscosity can be achieved for spin coating or slit coating.

[0150] In addition, phenolic resins, polymers containing a radically polymerizable monomer having an alkali-soluble group as monomer units, such as polyhydroxystyrene and acrylics, siloxane polymers, cyclic olefin polymers, and cardo resins may be used. Known resins among these may be used, or they may be used alone or in combination of a plurality of resins.

[0151] In the present invention, the resin composition containing the (A) resin preferably contains a (B) photosensitive agent (hereinafter sometimes referred to as the (B) component).

[0152] By containing the (B) component, the resin composition can be imparted with photosensitivity and a fine opening pattern can be formed.

[0153] (Component (B) is a compound whose chemical structure changes in response to ultraviolet light, and examples thereof include photoacid generators, photobase generators, and photopolymerization initiators. When a photoacid generator is used as component (B), an acid is generated in the irradiated portion of the photosensitive resin composition, and the solubility of the irradiated portion in an alkaline developer increases, so that a positive pattern in which the irradiated portion dissolves can be obtained.)

[0154] (When the component (B) contains a photobase generator, a base is generated in the irradiated portion of the resin composition, and the solubility of the irradiated portion in an alkaline developer decreases, so that a negative pattern in which the irradiated portion becomes insoluble can be obtained.)

[0155] (When the component (B) contains a photopolymerization initiator, radicals are generated in the irradiated portion of the resin composition and radical polymerization proceeds, and by becoming insoluble in an alkaline developer, a negative pattern can be formed. Further, UV curing during exposure is promoted, and the sensitivity can be improved.)

[0156] In the present invention, for the cured film obtained by curing the resin composition containing (A) resin and (B) component, the transmittance of light at a wavelength of 450 nm with a thickness reference of 5 μm is 80% or more and 100% or less. Thereby, it is possible to suppress the light emitted from the light-emitting element in all directions from being absorbed in the cured film obtained by curing the resin composition containing (A) resin and (B) component, improve the light extraction efficiency, and improve the luminance.)

[0157] (In order to obtain such characteristics, component (B) has a high transmittance of light at 450 nm itself, and has high heat resistance, for example, one having less formation of a quinone structure or the like which is one of the coloring structures, a high transmittance of light of the reaction product of component (B) with (A) resin, (C) thermocrosslinking agent, etc., and a high transmittance of light of the decomposition product of component (B) itself or the reaction product derived from the decomposable product are preferable. Further, it is preferable to perform an exposure treatment in order to reduce coloring during heat treatment before curing the resin composition containing component (B).)

[0158] The resin composition containing (A) resin and (B) component preferably has positive photosensitivity from the viewpoint of microfabricability.

[0159] Among the above-mentioned (B) components, a photoacid generator is preferred from the viewpoints of high sensitivity and microfabricability. Examples of the photoacid generator include quinonediazide compounds, sulfonium salts, phosphonium salts, diazonium salts, iodonium salts, etc. Further, a sensitizer or the like can be included as necessary.

[0160] As the quinonediazide compound, a compound in which a sulfonic acid of naphthoquinonediazide is ester-bonded to a compound having a phenolic hydroxyl group is preferred. As the compound having a phenolic hydroxyl group used herein, known compounds may be used, and those obtained by introducing 4-naphthoquinonediazide sulfonic acid or 5-naphthoquinonediazide sulfonic acid by an ester bond can be exemplified as preferred ones, but other compounds can also be used.

[0161] Also, it is preferable that 50 mol% or more of the entire functional groups of the compound having a phenolic hydroxyl group are substituted with quinonediazide. By using a quinonediazide compound substituted by 50 mol% or more, the affinity of the quinonediazide compound for an alkaline aqueous solution decreases. As a result, the solubility of the resin composition in the unexposed area in the alkaline aqueous solution greatly decreases. Further, the quinonediazide sulfonyl group is changed to indenecarboxylic acid by exposure, and a large dissolution rate of the photosensitive resin composition in the exposed area in the alkaline aqueous solution can be obtained. That is, as a result, the dissolution rate ratio between the exposed area and the unexposed area of the composition is increased, and a pattern with high resolution can be obtained.

[0162] By containing such a quinonediazide compound, a positive photosensitive resin composition that is sensitive to i-line (365 nm), h-line (405 nm), g-line (436 nm) of a general mercury lamp and a broadband containing them can be obtained. Further, the (B) component may be contained alone or in combination of two or more, and a highly sensitive resin composition can be obtained.

[0163] Examples of the quinonediazide include a 5-naphthoquinonediazide sulfonyl group, a 4-naphthoquinonediazide sulfonyl group, and those containing a 4-naphthoquinonediazide sulfonyl group and a 5-naphthoquinonediazide sulfonyl group in the same molecule.

[0164] Examples of the naphthoquinonediazide sulfonyl ester compound include a 5-naphthoquinonediazide sulfonyl ester compound (B-1) and a 4-naphthoquinonediazide sulfonyl ester compound (B-2). In the present invention, it is preferable to contain the (B-1) compound. The absorption of the (B-1) compound extends to the g-line region of a mercury lamp and is suitable for g-line exposure and full-wavelength exposure. Further, by reacting with a resin (A) or the like during curing, a crosslinked structure is formed, and the chemical resistance is improved. Furthermore, since the coloring after heat treatment is less than that of the (B-2) compound, it is also preferable from the viewpoint of the light transmittance after heat treatment. The content ratio of the (B-1) compound is preferably 55% by mass or more and 100% by mass or less with respect to the total photosensitizer amount of the (B-1) compound + (B-2) compound. By setting this content ratio, a cured film having a high light transmittance can be obtained.

[0165] The quinonediazide compound can be synthesized by a known method through an esterification reaction between a compound having a phenolic hydroxyl group and a quinonediazide sulfonic acid compound. By using the quinonediazide compound, the resolution, sensitivity, and residual film ratio are further improved.

[0166] From the viewpoints of the heat resistance, mechanical properties, and adhesiveness of the film obtained by heat treatment, the molecular weight of the component (B) is preferably 300 or more, more preferably 350 or more, preferably 3,000 or less, and more preferably 1,500 or less.

[0167] Among the component (B), sulfonium salts, phosphonium salts, and diazonium salts are preferable for appropriately stabilizing the acid component generated by exposure. Among them, sulfonium salts are preferable.

[0168] The content of component (B) is preferably 0.1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of resin (A). If the content of component (B) is 0.1 part by mass or more and 100 parts by mass or less, photosensitivity can be imparted while maintaining the heat resistance, chemical resistance, and mechanical properties of the film after heat treatment.

[0169] When component (B) contains a quinonediazide compound, the content of component (B) is more preferably 1 part by mass or more, even more preferably 3 parts by mass or more, with respect to 100 parts by mass of component (A). Also, it is more preferably 100 parts by mass or less, even more preferably 80 parts by mass or less. If it is 1 part by mass or more and 100 parts by mass or less, photosensitivity can be imparted while maintaining the heat resistance, chemical resistance, and mechanical properties of the film after heat treatment.

[0170] When component (B) contains a sulfonium salt, phosphonium salt, or diazonium salt, the content of component (B) is more preferably 0.1 part by mass or more, even more preferably 1 part by mass or more, particularly preferably 3 parts by mass or more, with respect to 100 parts by mass of resin (A). Also, it is more preferably 100 parts by mass or less, even more preferably 80 parts by mass or less, particularly preferably 50 parts by mass or less. If it is 0.1 part by mass or more and 100 parts by mass or less, photosensitivity can be imparted while maintaining the heat resistance, chemical resistance, and mechanical properties of the film after heat treatment.

[0171] When containing a photo-base generator as component (B), specific examples of the photo-base generator include amide compounds and ammonium salts.

[0172] Examples of the amide compound include 2-nitrophenylmethyl-4-methacryloyloxy piperidine-1-carboxylate, 9-anthrylmethyl-N,N-dimethylcarbamate, 1-(anthraquinone-2-yl)ethyl imidazole carboxylate, (E)-1-[3-(2-hydroxyphenyl)-2-propenoyl]piperidine, and the like.

[0173] Examples of the ammonium salt include 1,2-diisopropyl-3-(bis(dimethylamino)methylene)guanidinium 2-(3-benzoylphenyl)propionate, (Z)-{[bis(dimethylamino)methylidene]amino}-N-cyclohexylaminomethaniminium tetrakis(3-fluorophenyl)borate, 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidinium n-butyltriphenylborate, and the like.

[0174] When the photo-base generator is contained as the component (B), the content of the component (B) in the resin composition is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 0.7 part by mass or more, and particularly preferably 1 part by mass or more with respect to 100 parts by mass of the resin (A). When the content is within the above range, the sensitivity during exposure can be improved. On the other hand, the content is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 17 parts by mass or less, and particularly preferably 15 parts by mass or less. When the content is within the above range, the resolution after development can be improved.

[0175] When a photopolymerization initiator is contained as the component (B), examples of the photopolymerization initiator include benzyl ketal-based photopolymerization initiators, α-hydroxy ketone-based photopolymerization initiators, α-amino ketone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, oxime ester-based photopolymerization initiators, acridine-based photopolymerization initiators, benzophenone-based photopolymerization initiators, acetophenone-based photopolymerization initiators, aromatic ketoester-based photopolymerization initiators or benzoic acid ester-based photopolymerization initiators, and titanocene-based photopolymerization initiators. Known ones may be used alone or in combination of two or more. Among these, from the viewpoint of improving the sensitivity during exposure, α-hydroxy ketone-based photopolymerization initiators, α-amino ketone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, oxime ester-based photopolymerization initiators, acridine-based photopolymerization initiators or benzophenone-based photopolymerization initiators are more preferable, and α-amino ketone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and oxime ester-based photopolymerization initiators are still more preferable.

[0176] (B) When containing a photoinitiator as a component, the content of the component (B) in the resin composition is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 0.7 part by mass or more, and particularly preferably 1 part by mass or more with respect to 100 parts by mass of the resin (A). When the content is within the above range, the sensitivity during exposure can be improved. On the other hand, the content is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 17 parts by mass or less, and particularly preferably 15 parts by mass or less. When the content is within the above range, the resolution after development can be improved.

[0177] In the present invention, the resin composition containing the resin (A) preferably contains a (C) thermal crosslinking agent (hereinafter sometimes referred to as the component (C)). The thermal crosslinking agent refers to a resin or compound having at least two thermally reactive functional groups in the molecule. Examples of the thermally reactive functional group include compounds having an alkoxymethyl group, a methylol group, a cyclic ether group, and the like.

[0178] In the present invention, it is preferable to contain the component (C) because the chemical resistance is improved.

[0179] In the present invention, for the cured film obtained by curing the resin composition containing the resin (A), the component (B), and the component (C), the transmittance of light at a wavelength of 450 nm with a thickness standard of 5 μm is 80% or more and 100% or less. Thereby, it is possible to suppress the light emitted from the light-emitting element in all directions from being absorbed in the cured film obtained by curing the resin composition containing the resin (A), the component (B), and the component (C), improve the light extraction efficiency, and improve the luminance.

[0180] In order to obtain such characteristics, the component (C) has a high transmittance of light at 450 nm, high heat resistance, for example, less formation of a quinone structure which is one of the coloring structures, etc., a high transmittance of light of the reaction product of the component (B) and the resin (A), etc., and a high transmittance of light of the decomposition product of the component (C) itself or the reaction product derived from the decomposable product are preferred.

[0181] As a heat crosslinking agent, it may contain one or more compounds selected from alkoxymethyl compounds and methylol compounds (hereinafter may be abbreviated as component (C-1)). By including component (C-1), the crosslinking becomes stronger, and the chemical resistance of the cured film to, for example, a flux solution can be further improved. Specific examples of component (C-1) include the following methylol compounds, or alkoxymethyl compounds in which the hydrogen atom of the methylol group is substituted with a methyl group or an alkyl group having 2 to 10 carbon atoms, but are not limited to the following structures.

[0182]

Chemical formula

[0183]

Chemical formula

[0184] As component (C), it may contain one or more cyclic ether group compounds (hereinafter may be abbreviated as component (C-2)). By including component (C-2), it can react even at a low temperature of 160 °C or lower, and the crosslinking becomes stronger, and the chemical resistance of the cured film can be further improved.

[0185] Specific examples of the (C-2) component include "Denacol (registered trademark)" EX-212L, Denacol EX-214L, Denacol EX-216L, Denacol EX-850L, Denacol EX-321L (manufactured by Nagase ChemteX Corporation), GAN, GOT (manufactured by Nippon Kayaku Co., Ltd.), "Epicoat (registered trademark)" 828, Epicoat 1002, Epicoat 1750, Epicoat 1007, YX4000, YX4000H, YX8100-BH30, E1256, E4250, E4275 (manufactured by Mitsubishi Chemical Corporation), "Epiclon (registered trademark)" 850-S, Epiclon HP-4032, Epiclon HP-7200, Epiclon HP-820, Epiclon HP-4700, Epiclon HP-4770, Epiclon HP4032 (manufactured by Dainippon Ink and Chemicals, Inc.), TECHMORE VG3101L (manufactured by Printteck Co., Ltd.), "Topic (registered trademark)" S, Topic G, Topic P (manufactured by Nissan Chemical Industries, Ltd.), Epotote YH-434L (manufactured by Tokyo Chemical Industry Co., Ltd.), EPPN502H, NC-3000, NC-6000, XD-1000 (manufactured by Nippon Kayaku Co., Ltd.), Epiclon N695, HP7200 (manufactured by Dainippon Ink and Chemicals, Inc.), "Etanacol (registered trademark)" EHO, Etanacol OXBP, Etanacol OXTP, Etanacol OXMA (manufactured by Ube Industries, Ltd.), oxetane-modified phenol novolak, and the like.

[0186] Among them, those having a triarylmethane structure or a biphenyl structure are preferred. Specifically, YX4000, YX4000H (manufactured by Mitsubishi Chemical Corporation), TECHMORE VG3101L (manufactured by Printteck Co., Ltd.), NC-3000, and the like can be mentioned.

[0187] Furthermore, as the (C) component, one or more compounds containing a structural unit represented by the following general formula (5) (hereinafter, may be abbreviated as the (C-3) component) may be contained.

[0188]

Chemical formula

[0189] In general formula (5), R 25 is a divalent organic group having an alkylene group or alkylene ether group with 1 to 15 carbon atoms, and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, an ethylene oxide group, a propylene oxide group, a butylene oxide group, etc., and it may be linear, branched, or cyclic. Further, a part of the substituents of the divalent organic group having an alkylene group or alkylene ether group with 1 to 15 carbon atoms may have a cyclic ether group, an alkylsilyl group, an alkoxysilyl group, an aryl group, an aryl ether group, a carboxy group, a carbonyl group, an allyl group, a vinyl group, a heterocyclic group, or other substituents, or a combination thereof may be used. R 26 and R 27 each independently represents a hydrogen atom or a methyl group.

[0190] (Component (C-3)) itself has a flexible alkylene group and a rigid aromatic group. Therefore, by including component (C-3), the resulting cured film can have heat resistance, while also improving elongation and reducing stress.

[0191] Examples of the crosslinking group contained in component (C-3) include, but are not limited to, an acrylic group, a methylol group, an alkoxymethyl group, a cyclic ether group, etc. Among these, a cyclic ether group is preferable in terms of reacting with the hydroxyl group of resin (A) and improving the heat resistance of the cured film, and also in terms of being able to react without dehydration.

[0192] Examples of the compound containing the structural unit represented by general formula (5) include, but are not limited to, the following,

[0193] [Chemical formula]

[0194] In the formula, o 1 is an integer from 1 to 20, and o 2 is an integer from 1 to 5. From the viewpoint of achieving both heat resistance and improved elongation, o1 is an integer from 3 to 7, o 2 is preferably an integer from 1 to 2.

[0195] Two or more of the above (C) components may be contained in combination.

[0196] From the viewpoint of obtaining a cured film with high chemical resistance to, for example, a flux solution, the content of the (C) component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, based on 100 parts by mass of the (A) resin. Further, from the viewpoint of obtaining a cured film with high chemical resistance to, for example, a flux solution while maintaining the storage stability of the resin composition, and further suppressing peeling from the metal wiring and cracking of the cured film after the reliability test of the wiring to which the cured film is applied, it is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 80 parts by mass or less, based on 100 parts by mass of the (A) resin.

[0197] The resin composition containing the (A) resin may contain, as other components as necessary, a radically polymerizable compound, an antioxidant, a solvent, a compound having a phenolic hydroxyl group, an adhesion improver, an adhesion improver, and a surfactant.

[0198] Next, a method for producing the resin composition according to the present invention will be described. For example, the resin composition can be obtained by mixing and dissolving the (A) resin, and, if necessary, the (B) component, the (C) component, each radically polymerizable compound, antioxidant, solvent, compound having a phenolic hydroxyl group, adhesion improver, adhesion improver, surfactant, etc.

[0199] Examples of the dissolution method include known methods such as heating and stirring.

[0200] The viscosity of the resin composition is preferably 2 to 5,000 mPa·s. By adjusting the solid content concentration so that the viscosity is 2 mPa·s or more, it becomes easy to obtain a desired film thickness. On the other hand, if the viscosity is 5,000 mPa·s or less, it becomes easy to obtain a resin film with high uniformity. A resin composition having such a viscosity can be easily obtained, for example, by setting the solid content concentration to 5 to 60% by mass. Here, the solid content concentration refers to components other than the solvent.

[0201] The obtained resin composition is preferably filtered using a filtration filter to remove dust and particles. Examples of the material of the filtration filter include polypropylene (PP), polyethylene (PE), nylon (NY), and polytetrafluoroethylene (PTFE), with polyethylene and nylon being preferred.

[0202] When forming a cured film by curing a resin composition containing a resin (A), a resin sheet may be formed from the resin composition containing the resin (A) and then the resin sheet may be cured to form a film.

[0203] The resin sheet refers to a sheet formed on a substrate using the above resin composition. Specifically, it refers to a resin sheet obtained by applying the resin composition to a substrate and drying it.

[0204] A film such as polyethylene terephthalate (PET) can be used as the substrate on which the resin composition is applied. When the resin sheet is bonded to a substrate such as a silicon wafer and used, if it is necessary to peel off and remove the substrate, it is preferable to use a substrate coated with a release agent such as a silicone resin on the surface because the resin sheet and the substrate can be easily peeled off.

[0205] Next, a method for manufacturing the display device of the present invention will be described.

[0206] The manufacturing method of the display device of the present invention is a method for manufacturing a display device having at least a metal wiring, a cured film, and a plurality of light-emitting elements, comprising: a step (D1) of disposing the light-emitting elements on a support substrate; a step (D2) of forming a resin film made of a resin composition containing (A) resin on the support substrate and on the light-emitting elements; a step (D3) of forming a plurality of through-opening patterns in the resin film by exposing and developing the resin film; a step (D4) of curing the resin film to form the cured film having a light transmittance of 80% or more and 100% or less at a thickness reference of 5 μm for light with a wavelength of 450 nm; and a step (D5) of forming the metal wiring on at least a part of the surface of the cured film and in the opening patterns of the cured film.

[0207] Fig. 11 shows a cross-sectional view of a manufacturing process of an example of a display device having a plurality of light-emitting elements of the present invention.

[0208] Hereinafter, the resin film refers to a film obtained by applying a resin composition containing (A) resin to a substrate or laminating a resin sheet and drying it. The cured film refers to a film obtained by curing the resin film or the resin sheet.

[0209] In Fig. 11a, step (D1) is a step of disposing the light-emitting element 2 having a pair of electrode terminals 6 on the support substrate 20. The support substrate may be a glass substrate, a silicon substrate, ceramics, gallium arsenide, an organic circuit substrate, an inorganic circuit substrate, or a substrate on which circuit constituent materials are disposed on these substrates, but is not limited thereto. For example, a temporary bonding material may be disposed on the glass substrate or the silicon substrate. The TFT array substrate may also be used. The support substrate may be removed during the process, or another opposing substrate may be disposed after removal.

[0210] Next, as shown in Fig. 11b, step (D2) is a step of forming the resin film 21 by applying or laminating a resin composition containing (A) resin or a resin sheet formed from a resin composition containing (A) resin on the support substrate 20 and on the light-emitting element 2.

[0211] Note that "on the support substrate and on the light-emitting element" means not only the surfaces of the support substrate and the light-emitting element, but also above the support substrate and the light-emitting element. A resin composition containing (A) resin or a resin sheet formed from a resin composition containing (A) resin may be applied or laminated on a cured film, a metal wiring, a reflective film, or a partition wall to form a resin film.

[0212] Examples of the coating method include spin coating, slit coating, dip coating, spray coating, printing method, etc. Also, the coating film thickness varies depending on the coating technique, the solid content concentration of the composition, the viscosity, etc., but is usually applied so that the film thickness after drying is 0.1 to 150 μm.

[0213] Prior to coating, the support substrate on which the resin composition containing (A) resin is to be coated may be pretreated with the above-mentioned adhesion improver. For example, a method of treating the substrate surface by spin coating, slit die coating, bar coating, dip coating, spray coating, vapor treatment, etc. using a solution in which the adhesion improver is dissolved in a solvent such as isopropanol, ethanol, methanol, water, tetrahydrofuran, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, diethyl adipate, etc. at 0.5 to 20% by mass can be mentioned. After treating the substrate surface, a reduced-pressure drying treatment may be performed as necessary. Further, the reaction between the substrate and the adhesion improver may be advanced by heat treatment at 50°C to 280°C.

[0214] Next, the coating film of the resin composition containing (A) resin is dried to obtain a resin film 21. Drying is preferably performed for 1 minute to several hours in the range of 50°C to 140°C using an oven, a hot plate, infrared rays, etc.

[0215] On the one hand, when using the resin sheet, if the resin sheet has a protective film, the protective film is peeled off, the resin sheet is opposed to the support substrate, and they are bonded together by thermocompression bonding (in some cases, bonding the resin sheet to the support substrate by thermocompression bonding may be described as laminating the resin sheet on the support substrate). Next, the resin sheet laminated on the support substrate is dried in the same manner as when obtaining the resin film above to form a resin film 21. The resin sheet can be obtained by applying and drying a resin composition containing a resin on a support film made of polyethylene terephthalate or the like which is a peelable substrate.

[0216] Thermocompression bonding can be performed by heat press treatment, heat lamination treatment, heat vacuum lamination treatment, etc. The bonding temperature is preferably 40°C or higher from the viewpoints of adhesion to the substrate and embedding property. Further, when the resin sheet has photosensitivity, in order to prevent the resin sheet from curing during bonding and the resolution of pattern formation in the exposure and development processes from decreasing, the bonding temperature is preferably 140°C or lower.

[0217] Next, as shown in FIG. 11c, step (D3) is a step of forming a through-opening pattern 12 corresponding to the form of the metal wiring 4 on the resin film 21 using a photolithography process. (A) Since the resin composition or resin sheet containing a resin can be microfabricated, high-density arrangement of light-emitting elements is possible.

[0218] A chemical beam is irradiated through a mask having a desired pattern on the photosensitive resin film. Examples of the chemical beam used for exposure include ultraviolet rays, visible light rays, electron beams, X-rays, etc. In the present invention, it is preferable to use g-line (436 nm), h-line (405 nm), or i-line (365 nm), which are general exposure wavelengths. In the case of a non-photosensitive resin film, after forming a photoresist after forming the resin film, the above chemical beam is irradiated.

[0219] Develop the exposed photosensitive resin film 21. As the developer, an aqueous solution of a compound showing alkalinity such as tetramethylammonium, diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethylamine, methylamine, dimethylamine, dimethylaminoethyl acetate, dimethylaminoethanol, dimethylaminoethyl methacrylate, cyclohexylamine, ethylenediamine, hexamethylenediamine is preferred. In some cases, one or more polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, dimethylacrylamide, alcohols such as methanol, ethanol, isopropanol, esters such as ethyl lactate, propylene glycol monomethyl ether acetate, and ketones such as cyclopentanone, cyclohexanone, isobutyl ketone, methyl isobutyl ketone may be added to these alkaline aqueous solutions. After development, it is common to perform a rinsing treatment with water. Here, alcohols such as ethanol and isopropyl alcohol, esters such as ethyl lactate and propylene glycol monomethyl ether acetate may be added to water for rinsing treatment.

[0220] Next, as shown in FIG. 11c, step (D4) is a step of forming a cured film 3 having a light transmittance of 80% or more and 100% or less at a wavelength of 450 nm with a thickness standard of 5 μm by curing the resin film 21.

[0221] The resin film 21 is heated to cause a ring-closing reaction or a thermal crosslinking reaction to proceed, thereby obtaining a cured film 3. The cured film 3 has improved heat resistance and chemical resistance due to crosslinking between the (A) components or with the (B) component, (C) component, etc. This heat treatment may be carried out by gradually increasing the temperature stepwise, or by continuously increasing the temperature. It is preferable to carry out the heat treatment for 5 minutes to 5 hours. As an example, after heat treatment at 110°C for 30 minutes, further heat treatment at 230°C for 60 minutes can be cited. As the heat treatment conditions, it is preferably 140°C or higher and 400°C or lower. For the heat treatment conditions to allow the thermal crosslinking reaction to proceed, it is preferably 140°C or higher, more preferably 160°C or higher. Also, in order to provide an excellent cured film and improve the reliability of the display device, the heat treatment conditions are preferably 300°C or lower, more preferably 250°C or lower.

[0222] In addition, in order to obtain a cured film with a high light transmittance, it is preferably processed in an atmosphere with a low oxygen concentration during heating. The oxygen concentration is preferably 1000 ppm or less, more preferably 300 ppm or less, and even more preferably 50 ppm or less.

[0223] The cured film obtained in this way has an opening pattern, and it is preferable that the angle of the inclined side in the cross-section of the opening pattern is 40° or more and 85° or less. When the angle of the cross-sectional shape of the opening is 40° or more, a plurality of light-emitting elements can be efficiently arranged, enabling high definition. The angle of the cross-sectional shape of the opening is more preferably 50° or more. On the other hand, when the angle of the cross-sectional shape of the opening is 85° or less, wiring defects such as short circuits of the wiring can be suppressed. The angle of the cross-sectional shape of the opening is more preferably 80° or less.

[0224] Fig. 23 shows a front cross-sectional view of the opening pattern of the cured film. In Fig. 23, the angle of the inclined side 29 of the opening pattern formed in the cured film 3 is 30. The inclined side is defined as a straight line connecting the opening pattern at the position 32 which is 1 / 2 in the thickness direction of the cured film 3 and the bottom opening pattern.

[0225] Subsequently, in FIG. 11c, in order to improve the adhesion between the cured film 3 and the metal wiring 4, a barrier metal such as titanium is sputtered on the cured film 3, and a copper seed (seed layer) is further formed thereon by sputtering.

[0226] Next, in step (D5), as shown in FIG. 11d, after forming a photoresist layer (not shown), a metal wiring 4 made of copper or the like for electrically connecting to a pair of electrode terminals 6 of the light-emitting element 2 is formed on the opening pattern 12 of the cured film 3 and a part of the surface of the cured film 3 by plating or the like. Thereafter, unnecessary photoresist, seed layer, and barrier metal are removed.

[0227] Thereby, the electrical insulation of the metal wiring can be ensured by the cured film, and by extending the metal wiring in the cured film, the light-emitting operation can be controlled by electrically connecting a pair of electrode terminals of the light-emitting element and the driving element. In addition, since the cured film has a high light transmittance, absorption of light emitted from the light-emitting element can be suppressed, and light extraction performance can be enhanced.

[0228] The method for manufacturing a display device of the present invention preferably includes a step of repeating the step (D2), the step (D3), the step (D4), and the step (D5) a plurality of times to form a plurality of cured films having the metal wiring in the cured film.

[0229] As shown in FIGS. 11e to f, the cured film 3 and the metal wiring 4 can be repeatedly formed in the same manner to form a cured film 3 composed of two or more layers.

[0230] Thereby, by forming a plurality of cured films having metal wirings in the cured film, a plurality of light-emitting elements can be arranged, and wiring defects such as short circuits of wirings due to low-profile packages and short wiring distances can be suppressed, losses can be reduced, and high-speed responsiveness can be improved.

[0231] Thereafter, as shown in FIG. 11g, a barrier metal 9 is formed by sputtering on the opening pattern 12 of the cured film 3 to form solder bumps 10. Note that the barrier metal 9 may or may not be provided. The solder bumps 10 are electrically connected to, for example, a light-emitting element driving substrate 7 having a driving element such as a driver IC.

[0232] One driving element 8 may be used for one light-emitting element 2 according to function or a plurality of driving elements may be used for one unit of light-emitting elements 2 composed of red, blue, and green. For example, a plurality of driving elements may be arranged near the light-emitting elements during the process of FIG. 11. In that case, the driving element is electrically connected to the light-emitting element 2 through a metal wiring 4 extending in the cured film 3.

[0233] Thereafter, as shown in FIG. 11h, the light-emitting element driving substrate 7 having a driving element 8 such as a driver IC is electrically connected through the solder bumps 10, the support substrate 20 is peeled off, and the counter substrate 5 is bonded using an adhesive or the like, thereby obtaining a display device 1 having a plurality of light-emitting elements 2. Note that the metal wiring 4 may include electrodes.

[0234] Thereby, the electrical insulation of the metal wiring can be ensured by the cured film, and by extending the metal wiring in the cured film, the light-emitting operation can be controlled by electrically connecting a pair of electrode terminals of the light-emitting element and the driving element. In addition, since the cured film has a high light transmittance, absorption of light emitted from the light-emitting element can be suppressed, and light extraction efficiency can be improved.

[0235] The metal wiring 4 may be a conductive film 27. FIG. 30 shows a process in which the conductive film 27 is used instead of the metal wiring 4.

[0236] The method for manufacturing a display device may include a step (D6) of exposing the entire area of the resin film after the step (D3) and before the step (D4). By performing exposure after development, coloring during the heat treatment can be suppressed, and the transmittance of light with a wavelength of 450 nm after the heat treatment can be improved. In particular, it is particularly preferable when a photoacid generator is used as the component (B).

[0237] The method for manufacturing a display device of the present invention preferably includes a step (D7) of providing a partition wall having a thickness equal to or greater than the thickness of the light-emitting element before the step (D1). An example of the step (D7) is shown in FIG. 12. FIG. 12a is the step (D7) of providing a partition wall 16 having a thickness equal to or greater than the thickness of the light-emitting element 2 on the support substrate, and the next FIG. 12b shows the step (D1) of providing a plurality of light-emitting elements 2 between partition walls having a thickness equal to or greater than the thickness of the light-emitting element 2. FIG. 12c is a step of disposing the resin film 21 in the same manner as the step (D2) shown in FIG. 11b while the partition wall 16 is provided. The following steps proceed as shown in FIG. 11. As the partition wall, (A) resin may be used, or known ones such as epoxy resin, (meth)acrylic polymer, polyurethane, polyester, polyolefin, polysiloxane, etc. may be used. Further, a light-shielding portion or a reflecting portion may be provided.

[0238] The method for manufacturing a display device of the present invention preferably includes a step (D8) of providing a reflective film on a part of the cured film after the step (D4).

[0239] An example of the step (D8) is shown in FIG. 13. FIG. 13d shows the step (D8) of providing a reflective film 15 in a part of the region on the cured film 3.

[0240] The steps up to FIG. 13d are the same as the steps up to the step (D4) in FIG. 11c, and the step in the next FIG. 13e shows the step (D5) of forming the same metal wiring 4 as in FIG. 11d. The subsequent steps proceed in the order of the steps shown in FIG. 11 with the reflective film 15 provided. The reflective film is formed by a method such as sputtering using aluminum, silver, copper, titanium, or an alloy containing them. Further, it is preferable to protect the corresponding portion with a photoresist or the like in advance or perform sputtering using a predetermined mask so as not to overlap with the metal wiring to be formed later.

[0241] In the method for manufacturing a display device of the present invention, after the step (D5), it is further preferable to have a step (D9) including a driving element and a substrate, wherein the driving element is connected to a light-emitting element through a metal wiring, and at least a part of the metal wiring extends on a side surface of the substrate.

[0242] An example of the step (D9) is shown in FIG. 11. FIG. 11h shows the step (D9) including a driving element and a substrate, wherein the driving element is connected to a light-emitting element through a metal wiring. As shown in FIG. 11h, the driving element is connected to the light-emitting element 2 through the metal wirings 4 and 4c, and a part of the metal wiring 4c extends on a side surface of the light-emitting element driving substrate 7. When there is a through electrode on the light-emitting element driving substrate 7, the driving element 8 may be connected through the through electrode.

[0243] This improves the low-profile property and high-speed response property of the display device itself, and further enables the display device to be made smaller and have a narrower bezel.

[0244] The metal wiring 4c can be formed of, for example, gold, silver, copper, aluminum, nickel, titanium, tungsten, aluminum, tin, chromium, or an alloy containing these. When there is already wiring on the substrate or the light-emitting element driving substrate 7, that wiring may be used.

[0245] In the method for manufacturing a display device of the present invention, the corresponding metal wiring may be a conductive film (D10).

[0246] An example of the step (D10) is shown in FIG. 24. FIG. 24h shows that the driving element is connected to the light-emitting element 2 through the metal wiring 4 and the conductive film 27, and a part of the conductive film 27 extends on a side surface of the light-emitting element driving substrate 7.

[0247] This improves the low-profile property and high-speed response property of the display device itself, and further enables the display device to be made smaller and have a narrower bezel.

[0248] As the conductive film 27, a compound mainly containing an oxide of at least one element such as indium, gallium, zinc, tin, titanium, and niobium, an organic substance, a photosensitive conductive paste containing conductive particles, etc. are preferable.

[0249] The method for manufacturing the display device of the present invention preferably further has a step (D11) of having a light-shielding layer between the plurality of light-emitting elements.

[0250] An example of the step (D11) is shown in Fig. 25. Fig. 25a shows the step (D11) of providing a light-shielding layer 28 between the plurality of light-emitting elements 2. Further, the light-shielding layer 28 may be formed before forming the light-emitting element 2, or may be formed after forming the light-emitting element 2.

[0251] The light-shielding layer 28 may be composed of a cured film obtained by curing a resin composition containing (A) a resin and (E) a colorant, or may be composed of a material other than the resin composition containing (A) a resin. Known materials such as epoxy resin, (meth)acrylic polymer, polyurethane, polyester, polyolefin, polysiloxane, etc. may be used. As the (E) colorant, a black pigment may be used. For example, black organic pigments such as carbon black, perylene black, and aniline black, graphite, and metal fine particles, metal oxides, composite oxides, metal sulfides, metal nitrides, metal oxynitrides, etc. of metals such as titanium, copper, iron, manganese, cobalt, chromium, nickel, zinc, calcium, and silver can be mentioned. Further, a red pigment, a blue pigment, and optionally a yellow pigment and other pigments may be combined to make black. Also, a dye may be used. Two or more colorants may be contained.

[0252] Further, photosensitivity may be imparted to the resin composition containing (A) a resin and (E) a colorant, or the (B) photosensitizer described later may be used.

[0253] As a method for forming the light-shielding layer, a photolithography process may be used if it has photosensitivity. If it has no photosensitivity, after forming a photoresist on the light-shielding layer, a photolithography process or an etching process may be used, or an etching process using a mask may also be used. By subjecting the obtained pattern to a heat treatment (post-bake), a patterned colored film can be obtained. The heat treatment may be performed in any of air, a nitrogen atmosphere, and a vacuum state. The heating temperature is preferably 100 to 300 °C, and the heating time is preferably 0.25 to 5 hours. The heating temperature may be changed continuously or stepwise.

[0254] The method for manufacturing a display device of the present invention is a method for manufacturing a display device having at least a metal wiring, a cured film, and a plurality of light-emitting elements, and includes a step (E1) of disposing a metal pad on a support substrate, a step (E2) of forming a resin film made of a resin composition containing (A) a resin on the support substrate and on the metal pad, a step (E3) of forming a plurality of through-opening patterns in the resin film by exposing and developing the resin film, a step (E4) of curing the resin film to form the cured film having a light transmittance of 450 nm light at a thickness reference of 5 μm of 80% or more and 100% or less, a step (E5) of forming the metal wiring on at least a part of the surface of the cured film and in the opening pattern of the cured film, and a step (E6) of disposing the light-emitting element on the cured film so as to maintain electrical connection with the metal wiring.

[0255] Fig. 14 shows a cross-sectional view of a manufacturing process of another embodiment of the display device 1 of the present invention. The parts overlapping with the process of Fig. 11, specifically, Fig. 14b to e overlap with Fig. 11b to f, so the description is omitted.

[0256] As shown in Fig. 14a, step (E1) is a step of disposing a metal pad 18 on a support substrate 20.

[0257] Examples of the metal pad include copper and aluminum.

[0258] Next, as shown in FIG. 14b, step (E2) is a step of forming a resin film 21 by applying or laminating a resin composition or a resin sheet containing (A) resin on the support substrate 20 and the metal pad 18.

[0259] Note that on the support substrate and on the metal pad means not only the surface of the support substrate and the surface of the metal pad, but also any position above the support substrate and the metal pad. A resin composition containing (A) resin or a resin sheet formed from a resin composition containing (A) resin may be applied or laminated on a cured film, a metal wiring, a reflective film, or a partition wall to form a resin film.

[0260] Next, as shown in FIG. 14c, step (E3) is a step of forming a plurality of through-opening patterns 12 in the resin film 21 using a photolithography process.

[0261] Next, as shown in FIG. 14c, step (E4) is a step of forming a cured film 3 having a light transmittance of 80% or more and 100% or less at a wavelength of 450 nm with a thickness standard of 5 μm by curing the resin film 21.

[0262] Subsequently, in FIG. 14c, in order to improve the adhesion between the cured film 3 and the metal wiring 4, a barrier metal such as titanium is sputtered on the cured film 3, and a copper seed (seed layer) is further formed thereon by sputtering.

[0263] Next, as shown in FIG. 14d, step (E5) is a step of forming a metal wiring 4 made of copper or the like on the opening pattern 12 of the cured film 3 and a part of the surface of the cured film 3 by a plating method or the like after forming a photoresist layer (not shown). Thereafter, unnecessary photoresist, seed layer, and barrier metal are removed.

[0264] In the method for manufacturing a display device of the present invention, it is preferable to have a step of repeating the steps (E2), (E3), (E4), and (E5) a plurality of times to form a plurality of layers of the cured film having the metal wiring in the cured film.

[0265] As shown in FIGS. 14b to 14d, the cured film 3 and the metal wiring 4 can be repeatedly formed in the same manner again to form a cured film 3 composed of two or more layers as shown in FIG. 14e.

[0266] Next, as shown in FIG. 14f, step (E6) is a step of disposing the light-emitting element 2 on the cured film 3 while maintaining electrical connection with the metal wiring 4. The electrode terminal 6 of the light-emitting element 2 and the metal wiring 4 may be directly connected, or may be connected via, for example, solder balls.

[0267] Further, as shown in FIG. 14g, it is preferable to have a step (E7) of forming a cured film 22 on the cured film 3 and the light-emitting element 2. As the cured film 22, it is preferable to form a resin film made of a resin composition by applying a resin composition containing (A) resin or laminating a resin sheet composed of a resin composition containing (A) resin, and curing it to form the cured film 22. Further, it may be composed of a material other than the resin composition containing (A) resin and (B) photosensitizer, and known materials such as epoxy resin, silicone resin, and fluororesin may be used.

[0268] The curing conditions vary depending on the type of resin, and examples include 80°C to 230°C, 15 minutes to 5 hours, and the like.

[0269] This is for the purpose of protecting and planarizing the light-emitting element by forming a cured film on the light-emitting element.

[0270] Thereafter, as shown in FIG. 14h, a counter substrate 5 is bonded to the cured film 22 using an adhesive or the like. Further, the support substrate 20 is peeled off, a barrier metal 9 and bumps 10 are formed, and the light-emitting element driving substrate 7 with a driving element 8 such as a driver IC added is electrically connected via the solder bumps 10. The driving element 8 is electrically connected to the light-emitting element 2 via the metal wiring 4 extending in the cured film 3, thereby obtaining a display device 1 having a plurality of light-emitting elements 2. Note that the metal wiring 4 may include electrodes.

[0271] As a result, the cured film can ensure the electrical insulation of the metal wiring. By extending the metal wiring in the cured film, the light emission operation can be controlled by electrically connecting a pair of electrode terminals of the light-emitting element and the driving element. Further, since the cured film has a high light transmittance, absorption of the light emitted from the light-emitting element can be suppressed, and the light extraction efficiency can be improved.

[0272] The metal wiring 4 may be a conductive film 27. FIG. 31 shows the process of using the conductive film 27 instead of the metal wiring 4.

[0273] The manufacturing method of the display device of the present invention preferably includes a step (E8) of exposing the entire area of the resin layer after the step (E3) and before the step (E4).

[0274] By exposing the resin layer after development, coloring during the heat treatment can be suppressed, and the light transmittance at a wavelength of 450 nm after the heat treatment can be improved. This is particularly preferable when a photoacid generator is used as the component (B).

[0275] The manufacturing method of the display device of the present invention preferably includes a step (E9) of providing a partition wall having a thickness equal to or greater than the thickness of the light-emitting element after the step (E5).

[0276] An example of the step (E9) is shown in FIG. 15. FIG. 15f shows the step (E9) of providing the partition wall 16 after forming a plurality of layers of the cured film 3 shown in FIG. 14e. Then, as shown in FIG. 15g, the light-emitting element 2 is provided between the partition walls 16. Next, as shown in FIG. 15h, the counter substrate 5 is bonded to the upper part of the partition wall 16 and the light-emitting element 2, and the support substrate 20 is peeled off. The barrier metal 9 and the bumps 10 are formed, and the light-emitting element driving substrate 7 having a driving element 8 such as a driver IC is electrically connected via the solder bumps 10.

[0277] In the manufacturing method of the display device of the present invention, it is preferable to have a step (E10) of providing a reflective film on a part of the cured film before the step (E6) and after the step (E5).

[0278] An example of the process (E10) is shown in FIG. 16. FIG. 16f shows the process (E10) of providing the reflective film 15 after forming a plurality of layers of the cured film 3 shown in FIG. 14e. The subsequent processes are carried out in the order of the processes shown in FIGS. 14f, 14g, and 14h while the reflective film 15 is provided.

[0279] The manufacturing method of the display device of the present invention preferably includes, after the step (E7), a step (E11) having a driving element and a substrate, wherein the driving element is connected to a light-emitting element through a metal wiring, and at least a part of the metal wiring extends to a side surface of the substrate.

[0280] An example of the process (E11) is shown in FIG. 14. FIG. 14h shows the process (E11) having a driving element and a substrate, and the driving element is connected to a light-emitting element through a metal wiring. As shown in FIG. 14h, the driving element is connected to the light-emitting element 2 through the metal wirings 4 and 4c, and a part of the metal wiring 4c extends to the side surface of the light-emitting element driving substrate 7. When there is a through electrode on the light-emitting element driving substrate 7, it may be connected to the driving element 8 through the through electrode.

[0281] Thereby, the thickness reduction and high-speed response performance of the display device itself are improved, and the display device can be further miniaturized and have a narrower bezel.

[0282] The metal wiring 4c can be made of, for example, gold, silver, copper, aluminum, nickel, titanium, tungsten, aluminum, tin, chromium, or an alloy containing these. When there is already a wiring on the substrate or the light-emitting element driving substrate 7, that wiring may be used.

[0283] In the manufacturing method of the display device, the metal wiring may be a conductive film (E12). An example of the process (E12) is shown in FIG. 26. FIG. 26h shows that the driving element is connected to the light-emitting element 2 through the metal wirings 4 and the conductive layer 27, and a part of the conductive film 27 extends to the side surface of the light-emitting element driving substrate 7.

[0284] As a result, the thickness of the display device itself can be reduced, the high-speed response performance can be improved, and further, the display device can be made smaller in size and have a narrower bezel.

[0285] The conductive film 27 contains, as a main component, a compound containing an oxide of at least one element among indium, gallium, zinc, tin, titanium, and niobium. or A photosensitive conductive paste containing an organic substance and conductive particles is preferable.

[0286] The method for manufacturing a display device according to the present invention is a method for manufacturing a display device having at least wiring, a cured film, and a plurality of light-emitting elements, and includes a step (F1) of forming a resin film made of a resin composition containing a resin on a substrate or the like, a step (F2) of forming a plurality of through-opening patterns in the resin film by exposing and developing the resin film, a step (F3) of curing the resin film to form the cured film having a light transmittance of 80% or more and 100% or less at a wavelength of 450 nm with a thickness reference of 5 μm, a step (F4) of forming the wiring on at least a part of the surface of the cured film and a part of the opening pattern of the cured film, and a step (F5) of disposing the light-emitting element on the cured film so as to maintain electrical connection with the wiring.

[0287] FIG. 27 shows a cross-sectional view of a manufacturing process of another embodiment of the display device 1 according to the present invention.

[0288] As shown in FIG. 27a, step (F1) is a step of forming a resin film made of a resin composition containing a resin on a substrate or the like. The resin composition containing the resin (A) or a resin sheet formed from the resin composition containing the resin (A) may be applied or laminated to form the resin film.

[0289] As the substrate, a light-emitting element driving substrate 7 can be used. FIG. 27a shows, as an example, a TFT array substrate in which TFTs 23, insulating films 24, and metal wirings 4 are arranged on a glass substrate.

[0290] Examples of the metal wiring 4 include gold, silver, copper, aluminum, nickel, titanium, molybdenum, and alloys containing these. The insulating film 24 is not particularly limited, and examples include a silicon oxide film, a silicon nitride film, and an insulating film made of an organic substance.

[0291] Next, as shown in Fig. 27a, the step (F2) is a step of forming a plurality of through-opening patterns in the resin film using a photolithography process.

[0292] Next, as shown in Fig. 27a, the step (F3) is a step of forming a cured film 3 having a light transmittance of 80% or more and 100% or less for light with a wavelength of 450 nm at a thickness reference of 5 μm by curing the resin film.

[0293] Next, as shown in Fig. 27b, the step (F4) is a step of forming wiring on at least a part of the surface of the cured film and a part of the opening pattern of the cured film. After forming a photoresist layer (not shown), for example, it is a step of forming the wiring 25 on the surface of a part of the cured film 3 by a sputtering method or the like. Then, unnecessary photoresist is removed.

[0294] Examples of the wiring include metal wiring, a compound containing at least one of indium, gallium, zinc, tin, titanium, and niobium as a main component of an oxide thereof, an organic substance, and a photosensitive conductive paste containing conductive particles, but other known ones may also be used.

[0295] The manufacturing method of the display device of the present invention preferably includes a step of repeating the step (F1), the step (F2), the step (F3), and the step (F4) a plurality of times to form a plurality of layers of the cured film having the wiring in the cured film.

[0296] The cured film 3 can be formed into a cured film 3 composed of two or more layers as shown in Fig. 27c by repeating the same method again.

[0297] Next, as shown in Fig. 27d, step (F5) is a step of disposing the light-emitting element 2 on the cured film 3 while maintaining an electrical connection with the wiring 25. The electrode terminal 6 of the light-emitting element 2 and the wiring 25 may be directly connected, or may be connected via, for example, a solder ball or the like. The partition wall 16 may be formed before or after disposing the light-emitting element 2.

[0298] Thereafter, as shown in Fig. 27e, the counter substrate 5 is bonded using an adhesive or the like. Further, a conductive film 27 is formed, and the driving element 8 such as a driver IC is electrically connected to the light-emitting element 2 through the metal wiring 4 and the wiring 25 extending in the cured film 3 through the conductive film 27, thereby obtaining the display device 1 having a plurality of light-emitting elements 2. Note that the wiring 25 includes electrodes.

[0299] Thereby, the electrical insulation of the wiring can be ensured by the cured film, and by extending the wiring in the cured film, the light-emitting operation can be controlled by electrically connecting a pair of electrode terminals of the light-emitting element and the driving element. Further, since the cured film has a high light transmittance, absorption of light emitted from the light-emitting element can be suppressed, and the light extraction property can be enhanced.

[0300] The display device of the present invention is suitably used for display devices such as various LED displays and various in-vehicle lamps.

Example

[0301] Hereinafter, the present invention will be described with reference to examples and the like, but the present invention is not limited to these examples. Note that the evaluation of the display device in the examples and the cured film made of the resin composition used in the display device was performed by the following method.

[0302] <Evaluation method of light transmittance of cured film> A varnish made of a resin composition was spin-coated on a 5 cm angled glass substrate so that the film thickness after heat treatment was 5.0 μm, and pre-baked at 120 °C for 3 minutes. Then, using a high-temperature clean oven CLH-21CD-S manufactured by Kouyou Thermo System Co., Ltd., under a nitrogen stream, the temperature was raised from 50 °C to 110 °C at a rate of 3.5 °C / min with an oxygen concentration of 100 ppm or less, and then heat treatment was carried out at 110 °C for 30 minutes. Then, the temperature was raised to 230 °C, which is the heating temperature, at a rate of 3.5 °C / min, and then heat treatment was carried out at the heating temperature after the temperature rise for 1 hour to dry and heat-treat the coating film to obtain a cured film. In addition, the film thickness of the coating film after pre-baking and after development was measured using a light interference film thickness measuring device Lambda Ace STM-602 manufactured by Dainippon Screen Mfg. Co., Ltd., with a refractive index of 1.629, and the film thickness of the cured film was measured with a refractive index of 1.629.

[0303] Regarding the cured film thus obtained, the transmittance at a wavelength of 450 nm was measured using a double-beam spectrophotometer U-2910 (manufactured by Hitachi High-Technologies Corporation). Also, when the film thickness of the heat-resistant resin film after heat treatment was not 5 μm, the value obtained by converting the film thickness of the measured transmission spectrum to 5 μm in accordance with Lambert's law was used.

[0304] <Evaluation Method for Light Extraction Efficiency of Display Device> Using the display devices described in the following Examples and Comparative Examples, the light extraction efficiency was measured. For the measurement, an external quantum efficiency measuring device C9920 manufactured by Hamamatsu Photonics K.K. was used. The light extraction efficiency was evaluated as a relative evaluation with respect to the value of 1.00 for the light extraction efficiency of the display device of Example 1.

[0305] <Evaluation of Aperture Pattern Shape of Cured Film Made of Resin Composition> A varnish was prepared and spin-coated and pre-baked on an 8-inch silicon wafer using a coating and developing apparatus ACT-8 (manufactured by Tokyo Electron Limited) so that the film thickness after heat treatment was 5 μm to prepare a pre-baked film. The pre-baking was carried out at 120 °C for 3 minutes. Then, using an i-line stepper (manufactured by Nikon Corporation, NSR-2205i14), 50 to 1000 mJ / cm 2Exposure was carried out with the exposure amount. The size of the circular pattern used for exposure was 5 to 30 μm. After exposure, a 2.38 mass% aqueous solution of tetramethylammonium (TMAH) (manufactured by Tama Chemical Industry Co., Ltd.) was used for development under conditions such that the film thickness change of the unexposed portion before and after development was 1.0 to 1.5 μm. Subsequently, rinsing was performed with pure water, spin-drying was carried out, and a pattern-forming film was obtained. Alternatively, development was carried out using cyclopentanone, spin-drying was carried out, and a pattern-forming film was obtained. In the case of a non-photosensitive material, a photoresist was formed before exposure, followed by exposure and development, and the photoresist was removed after development. The film thicknesses after pre-baking and after development were measured using a light interference film thickness measuring device Lambda Ace STM-602 manufactured by Dainippon Screen Mfg. Co., Ltd., assuming a refractive index of 1.629.

[0306] After development, an inert oven CLH-21CD-S (manufactured by Koyo Thermo System Co., Ltd.) was used, and under a nitrogen stream, the temperature was raised from 50 °C to 100 °C at a rate of 3.5 °C / min with an oxygen concentration of 20 ppm or less, and then a heat treatment was carried out at 100 °C for 30 minutes. Subsequently, the temperature was raised to 230 °C at a rate of 3.5 °C / min, and then a heat treatment was carried out for 1 hour to cure the pattern-forming film and obtain a cured film.

[0307] After the temperature reached 50 °C or lower, the wafer was taken out, the wafer was cleaved, and the cross-sectional shape of the 5 to 30 μm circular pattern was observed and measured using a scanning electron microscope S-4800 (manufactured by Hitachi High-Tech). The angle of the inclined side was obtained using as the inclined side the straight line connecting the opening pattern at the position that was 1 / 2 in the thickness direction of the cured film and the opening pattern at the bottom.

[0308] As a result, those with an inclined side angle of 50° or more and 80° or less were evaluated as level A, those with an inclined side angle of 40° or more and less than 50° or more than 80° and 85° or less were evaluated as level B, and those with an inclined side angle less than 40° or more than 85° were evaluated as level C.

[0309] <Synthesis Example 1 Synthesis of Hydroxyl Group-Containing Diamine Compound> 18.3 g (0.05 mol) of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (manufactured by Central Glass Co., Ltd., hereinafter referred to as BAHF) was dissolved in 100 mL of acetone and 17.4 g (0.3 mol) of propylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) and cooled to -15°C. A solution prepared by dissolving 20.4 g (0.11 mol) of 3-nitrobenzoyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) in 100 mL of acetone was added dropwise thereto. After completion of the addition, the mixture was stirred at -15°C for 4 hours and then returned to room temperature. The precipitated white solid was filtered off and dried in vacuo at 50°C.

[0310] 30 g of the obtained white solid was placed in a 300 mL stainless steel autoclave, dispersed in 250 mL of methyl cellosolve, and 2 g of 5% palladium-carbon (manufactured by Wako Pure Chemical Industries, Ltd.) was added. Hydrogen was introduced by balloon and the reduction reaction was carried out at room temperature. After about 2 hours, the reaction was terminated after confirming that the balloon no longer shrank. After completion of the reaction, the mixture was filtered to remove the palladium compound as a catalyst, concentrated by a rotary evaporator, and a hydroxyl group-containing diamine compound represented by the following formula was obtained.

[0311] [Chemical formula]

[0312] <Synthesis Example 2 Synthesis of Polybenzoxazole Precursor (A-1)> Under a stream of dry nitrogen, 1.5 g (0.0075 mol) of 4,4'-diaminodiphenyl ether (hereinafter referred to as 4,4'-DAE), 12.8 g (0.035 mol) of BAHF, and 5.0 g (0.0050 mol) of RT-1000 (manufactured by HUNTSMAN Co., Ltd.) were dissolved in 100 g of NMP. To this, diimidazole dodecanoate (7.4 g, 0.023 mol) and 1,1'-(4,4'-oxybenzoyl) diimidazole (hereinafter referred to as PBOM) (8.1 g, 0.023 mol) were added together with 25 g of NMP, and the mixture was reacted at 85°C for 3 hours. Next, 0.6 g (0.0025 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane (hereinafter referred to as SiDA), 0.8 g (0.0025 mol) of 4,4'-oxydiphthalic anhydride (hereinafter referred to as ODPA), and 0.8 g (0.0050 mol) of 5-norbornene-2,3-dicarboxylic anhydride (hereinafter referred to as NA) were added together with 25 g of NMP, and the mixture was reacted at 85°C for 1 hour. After completion of the reaction, the reaction mixture was cooled to room temperature, 13.2 g (0.25 mol) of acetic acid was added together with 25 g of NMP, and the mixture was stirred at room temperature for 1 hour. After completion of the stirring, the solution was poured into 1.5 L of water to obtain a white precipitate. This precipitate was collected by filtration, washed three times with water, and then dried in a ventilated dryer at 50°C for 3 days to obtain a powder of polybenzoxazole precursor (A-1).

[0313] <Synthesis Example 3 Synthesis of Polybenzoxazole Precursor (A-2)> Under a stream of dry nitrogen, 27.5 g (0.075 mol) of BAHF was dissolved in 257 g of NMP. To this, 17.2 g (0.048 mol) of PBOM was added together with 20 g of NMP, and the mixture was reacted at 85 °C for 3 hours. Subsequently, 20.0 g (0.02 mol) of RT-1000, 1.2 g (0.005 mol) of SiDA, and 14.3 g (0.04 mol) of PBOM were added together with 50 g of NMP, and the mixture was reacted at 85 °C for 1 hour. Further, as a terminal blocking agent, 3.9 g (0.024 mol) of NA was added together with 10 g of NMP, and the mixture was reacted at 85 °C for 30 minutes. After completion of the reaction, the mixture was cooled to room temperature, 52.8 g (0.50 mol) of acetic acid was added together with 87 g of NMP, and the mixture was stirred at room temperature for 1 hour. After completion of the stirring, the solution was poured into 3 L of water to obtain a white precipitate. This precipitate was collected by filtration, washed three times with water, and then dried in a ventilated dryer at 50 °C for 3 days to obtain a powder of polybenzoxazole precursor (A-2).

[0314] <Synthesis Example 4 Synthesis of Polyimide Precursor (A-3)> Under a stream of dry nitrogen, 51.9 g (0.086 mol) of the hydroxyl group-containing diamine obtained in Synthesis Example 1 and 1.0 g (0.004 mol) of SiDA were dissolved in 200 g of NMP. To this, 31.0 g (0.10 mol) of ODPA was added, and the mixture was stirred at 40 °C for 2 hours. Then, as a terminal blocking agent, 1.1 g (0.01 mol) of 3-aminophenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was added together with 10 g of NMP, and the mixture was reacted at 40 °C for 1 hour. Thereafter, a solution prepared by diluting 7.1 g (0.06 mol) of dimethylformamide dimethylacetal (manufactured by Mitsubishi Rayon Co., Ltd., hereinafter referred to as DFA) with 5 g of NMP was added dropwise. After the addition, stirring was continued at 40 °C for 2 hours. After completion of the stirring, the solution was poured into 2 L of water, and the precipitate of the polymer solid was collected by filtration. Further, the collected polymer solid was washed three times with 2 L of water and dried in a vacuum dryer at 50 °C for 72 hours to obtain a polyimide precursor (A-3).

[0315] <Synthesis Example 5 Synthesis of Polyimide Precursor (A-4)> Under a stream of dry nitrogen, 41.1 g (0.068 mol) of the hydroxyl group-containing diamine obtained in Synthesis Example 1, 18.0 g (0.018 mol) of RT-1000, and 1.0 g (0.004 mol) of SiDA were dissolved in 200 g of NMP. 31.0 g (0.10 mol) of ODPA was added thereto, and the mixture was stirred at 40 °C for 2 hours. Then, 1.1 g (0.01 mol) of 3-aminophenol as a terminal capping agent was added together with 10 g of NMP, and the reaction was carried out at 40 °C for 1 hour. Thereafter, a solution obtained by diluting 6.0 g (0.05 mol) of DFA with 5 g of NMP was added dropwise. After the addition, stirring was continued at 40 °C for 2 hours. After completion of stirring, the solution was poured into 2 L of water, and the precipitate of the polymer solid was collected by filtration. Further, washing was performed 3 times with 2 L of water, and the collected polymer solid was dried in a vacuum dryer at 50 °C for 72 hours to obtain a polyimide precursor (A-4).

[0316] <Synthesis Example 6 Synthesis of Polyimide (A-5)> Under a stream of dry nitrogen, 29.3 g (0.08 mol) of BAHF, 1.2 g (0.005 mol) of SiDA, and 3.3 g (0.03 mol) of 3-aminophenol as a terminal capping agent were dissolved in 80 g of NMP. 31.2 g (0.1 mol) of ODPA was added thereto together with 20 g of NMP, and the reaction was carried out at 60 °C for 1 hour, and then stirred at 180 °C for 4 hours. After completion of stirring, the solution was poured into 3 L of water to obtain a white precipitate. This precipitate was collected by filtration, washed 3 times with water, and then dried in a vacuum dryer at 80 °C for 20 hours to obtain a powder of polyimide (A-5).

[0317] <Synthesis Example 7 Synthesis of Cardo Resin (A-6)> Under a dry nitrogen stream, 198.53 g of a 50% PGMEA solution of an equimolar reactant of bisphenol fluorene type epoxy resin and acrylic acid (manufactured by Nippon Steel Chemical Co., Ltd., product name "ASF-400" solution), 39.54 g (0.12 mol) of benzophenone tetracarboxylic dianhydride, 8.13 g (0.08 mol) of succinic anhydride, 48.12 g of PGMEA, and 0.45 g of triphenylphosphine were charged into a four-necked flask equipped with a reflux condenser. The mixture was stirred at 120 - 125 °C for 1 hour under heating, and further stirred at 75 - 80 °C for 6 hours. Then, 8.6 g of glycidyl methacrylate was added, and the mixture was further stirred at 80 °C for 8 hours to obtain a resin (A-6) having a skeletal structure in which two cyclic structures are bonded to a quaternary carbon atom constituting the cyclic structure.

[0318] <Synthesis Example 8 Synthesis of Polyimide Precursor (A-7)> Under a dry nitrogen stream, 3.2 g (0.03 mol) of 1,4-phenylenediamine and 12.0 g (0.06 mol) of 4,4'-DAE were dissolved in 200 g of NMP. 31.0 g (0.10 mol) of ODPA was added thereto, and the mixture was stirred at 40 °C for 2 hours. Then, 1.1 g (0.01 mol) of 3-aminophenol (manufactured by Tokyo Chemical Industry Co., Ltd.) as a terminal blocking agent was added together with 10 g of NMP, and the reaction was carried out at 40 °C for 1 hour. Thereafter, a solution obtained by diluting 7.1 g (0.06 mol) of DFA with 5 g of NMP was added dropwise. After the dropwise addition, stirring was continued at 40 °C for 2 hours. After completion of stirring, the solution was poured into 2 L of water, and the precipitate of the polymer solid was collected by filtration. Further, washing was carried out 3 times with 2 L of water, and the collected polymer solid was dried in a vacuum dryer at 50 °C for 72 hours to obtain a polyimide precursor (A-7).

[0319] <Synthesis Example 9 Synthesis of Polyimide Precursor (A-8)> 155.1 g (0.50 mol) of ODPA was placed in a separable flask with a capacity of 2 liters, and 134.0 g (1.00 mol) of 2-hydroxyethyl methacrylate (HEMA) and 400 g of γ-butyrolactone were added. While stirring at room temperature, 79.1 g of pyridine was added to obtain a reaction mixture. After the exotherm of the reaction ended, the mixture was allowed to cool to room temperature and further allowed to stand for 16 hours.

[0320] Next, under ice-cooling, a solution prepared by dissolving 206.3 g (1.00 mol) of dicyclohexylcarbodiimide (DCC) in 180 g of γ-butyrolactone was added to the reaction mixture over 40 minutes with stirring. Subsequently, a suspension prepared by suspending 16.2 g (0.15 mol) of 1,4-phenylenediamine and 60.1 g (0.30 mol) of 4,4'-DAE in 350 g of γ-butyrolactone was added over 60 minutes with stirring. After further stirring at room temperature for 2 hours, 30 ml of ethyl alcohol was added and stirred for 1 hour. Then, 400 g of γ-butyrolactone was added. The precipitate formed in the reaction mixture was removed by filtration to obtain a reaction solution.

[0321] The reaction solution was poured into 3 L of water to obtain a white precipitate. This precipitate was collected by filtration, washed twice with water, once with isopropanol, and then dried in a vacuum dryer at 50°C for 72 hours to obtain a polyimide precursor (A-8).

[0322] <Synthesis Example 10 Synthesis of Photosensitizer (Quinonediazide Compound) (B-1)> Under a dry nitrogen stream, 21.2 g (0.05 mol) of 4,4'-[1-[4-[1-(4-hydroxyphenyl-1)-1-methylethyl]phenyl]ethylidene]bisphenol (manufactured by Nippon Kayaku Co., Ltd., hereinafter referred to as TrisP-PA) and 26.8 g (0.10 mol) of 5-naphthoquinonediazide sulfonic acid chloride (NAC-5 manufactured by Toyo Gosei Co., Ltd.) were dissolved in 450 g of γ-butyrolactone at room temperature. To this, 12.7 g of triethylamine mixed with 50 g of γ-butyrolactone was added dropwise so that the temperature inside the system did not exceed 35°C. After the addition, the mixture was stirred at 40°C for 2 hours. The triethylamine salt was filtered off, and the filtrate was poured into water. Subsequently, the precipitated precipitate was collected by filtration and further washed with 1 L of 1% hydrochloric acid aqueous solution. Then, it was further washed twice with 2 L of water. This precipitate was dried in a vacuum dryer to obtain a quinonediazide compound (B-1) represented by the following formula.

[0323]

Chemical formula

[0324] <Synthesis Example 11 Synthesis of Photosensitizer (Quinonediazide Compound) (B-2)> Under a dry nitrogen stream, 21.2 g (0.05 mol) of TrisP-PA and 26.8 g (0.10 mol) of 4-naphthoquinonediazide sulfonic acid chloride (manufactured by Toyo Gosei Co., Ltd., NAC-5) were dissolved in 450 g of γ-butyrolactone at room temperature. To this, 12.7 g of triethylamine mixed with 50 g of γ-butyrolactone was added dropwise so that the temperature inside the system did not exceed 35°C. After the addition, the mixture was stirred at 40°C for 2 hours. The triethylamine salt was filtered off, and the filtrate was poured into water. Then, the precipitated precipitate was collected by filtration and washed with 1 L of 1% hydrochloric acid water. Thereafter, it was further washed twice with 2 L of water. This precipitate was dried in a vacuum dryer to obtain a quinonediazide compound (B-2) represented by the following formula.

[0325] [Chemical Formula]

[0326] <Synthesis Example 12 Synthesis of Polyimide Precursor (A-10)> 155.1 g (0.50 mol) of ODPA was placed in a 2-liter separable flask, and 134.0 g (1.00 mol) of 2-hydroxyethyl methacrylate (HEMA) and 400 g of γ-butyrolactone were added. While stirring at room temperature, 79.1 g of pyridine was added to obtain a reaction mixture. After the exothermic reaction ended, the mixture was allowed to cool to room temperature and further allowed to stand for 16 hours.

[0327] Next, under ice cooling, a solution of 206.3 g (1.00 mol) of dicyclohexylcarbodiimide (DCC) dissolved in 180 g of γ-butyrolactone was added dropwise to the reaction mixture over 40 minutes while stirring. Subsequently, a suspension of 90.2 g (0.45 mol) of 4,4'-DAE suspended in 350 g of γ-butyrolactone was added dropwise to the reaction mixture over 60 minutes while stirring. After further stirring at room temperature for 2 hours, 30 ml of ethyl alcohol was added and stirred for 1 hour. Thereafter, 400 g of γ-butyrolactone was added. The precipitate formed in the reaction mixture was removed by filtration to obtain a reaction solution.

[0328] The reaction solution was poured into 3 L of water to obtain a white precipitate. This precipitate was collected by filtration, washed twice with water, once with isopropanol, and then dried in a vacuum dryer at 50 °C for 72 hours to obtain a polyimide precursor (A-10).

[0329] <Synthesis Example 13: Synthesis of Acrylic Resin (A-11)> 33 g of methyl methacrylate, 33 g of styrene, 34 g of methacrylic acid, 3 g of 2,2'-azobis(2-methylbutyronitrile), and 150 g of propylene glycol monomethyl ether acetate (hereinafter, "PGMEA") were charged into a polymerization vessel, stirred at 90 °C for 2 hours, then the liquid temperature was raised to 100 °C and reacted for another 1 hour. 33 g of glycidyl methacrylate, 1.2 g of dimethylbenzylamine, and 0.2 g of p-methoxyphenol were added to the obtained reaction solution, and the mixture was stirred at 90 °C for 4 hours. At the end of the reaction, 50 g of PGMEA was added to obtain a solution of acrylic resin (A-11) (solid content: 40% by mass). The acid value of acrylic resin (A-11) was 80.0 (mg / KOH / g), and the weight average molecular weight (Mw) was 22,000.

[0330] <Synthesis Example 14: Synthesis of Acrylic Resin (A-12)> 150 g of dimethylaminomethanol (hereinafter, "DMEA"; manufactured by Tokyo Chemical Industry Co., Ltd.) was charged into a reaction vessel under a nitrogen atmosphere, and the temperature was raised to 80°C using an oil bath. To this, a mixture consisting of 20 g of ethyl acrylate (hereinafter, "EA"), 40 g of 2-ethylhexyl methacrylate (hereinafter, "2-EHMA"), 20 g of styrene (hereinafter, "St"), 15 g of acrylic acid (hereinafter, "AA"), 0.8 g of 2,2'-azobisisobutyronitrile, and 10 g of DMEA was added dropwise over 1 hour. After completion of the dropwise addition, a polymerization reaction was further carried out at 80°C under a nitrogen atmosphere for 6 hours. Thereafter, 1 g of hydroquinone monomethyl ether was added to stop the polymerization reaction. Subsequently, a mixture consisting of 5 g of glycidyl methacrylate (hereinafter, "GMA"), 1 g of triethylbenzylammonium chloride, and 10 g of DMEA was added dropwise over 0.5 hour. After completion of the dropwise addition, an addition reaction was further carried out at 80°C under a nitrogen atmosphere for 2 hours. The obtained reaction solution was purified with methanol to remove unreacted impurities, and further dried under vacuum for 24 hours to obtain an acrylic resin (A-12) with a copolymerization ratio (by mass): EA / 2-EHMA / St / GMA / AA = 20 / 40 / 20 / 5 / 15. The acid value of the obtained resin (A-12) was 103 mgKOH / g.

[0331] <Synthesis Example 15 Synthesis of Acrylic Resin (A-13)> A methyl methacrylate / methacrylic acid / styrene copolymer (weight ratio 30 / 40 / 30) was synthesized by the method described in Example 1 of Japanese Patent No. 3120476. To 100 parts by weight of the obtained copolymer, 40 parts by weight of glycidyl methacrylate was added, reprecipitated with purified water, filtered, and dried to obtain an acrylic resin (A-13) having a weight average molecular weight of 15,000 and an acid value of 110 mgKOH / g.

[0332] <Preparation Example 1 Preparation of Photosensitive Conductive Paste 1> In a 100 mL clean bottle, 10.0 g of resin (A-12) as the resin, 0.50 g of "IRGACURE (registered trademark)" OXE-01 (manufactured by Ciba Japan Co., Ltd.) as the photoinitiator, 5.0 g of DMEA as the solvent, and 2.0 g of "Light Acrylate (registered trademark)" BP-4EA (manufactured by Kyoeisha Chemical Co., Ltd.) as the compound having an unsaturated double bond were put, and mixed using a planetary-centrifugal vacuum mixer "Awatori Rentaro ARE-310" (manufactured by Shin-Kee Co., Ltd.) to obtain 17.5 g of a resin solution (solid content 71.4 mass%).

[0333] The obtained 17.50 g of the resin solution was mixed with 44.02 g of silver particles having an average particle diameter of 1.0 μm and 0.28 g of carbon black having an average particle diameter of 0.05 μm, and kneaded using a three-roll mill "EXAKT M-50" (manufactured by EXAKT) to obtain 61.8 g of photosensitive conductive paste 1. The average particle diameters of the silver particles and carbon black were observed for each particle at a magnification of 10,000 times and a field width of 12 μm using an electron microscope (SEM), and the maximum widths of 40 randomly selected silver particles and primary particles of carbon black were measured, and their number average values were calculated.

[0334] <Preparation Example 2 Production of Colorant Dispersion Liquid (DC-1)> As the colorant, zirconia compound particles Zr-1 (manufactured by Nisshin Engineering Co., Ltd.) produced by the thermal plasma method were used. 200 g of Zr-1, 114 g of a 35 wt% solution of acrylic polymer (P-1) in propylene glycol monomethyl ether acetate (PGMEA), 625 g of "DISPERBYK (registered trademark)" LPN-2111 having a tertiary amino group and a quaternary ammonium salt as the polymer dispersant, and 661 g of PGMEA were charged into a tank and stirred with a homomixer for 20 minutes to obtain a preliminary dispersion liquid. The obtained preliminary dispersion liquid was supplied to a dispersion machine Ultra Apex Mill manufactured by Kotobuki Industries Co., Ltd. equipped with a centrifugal separator filled with 75 vol% of 0.05 mmφ zirconia beads, and dispersed at a rotational speed of 8 m / s for 3 hours to obtain a colorant dispersion liquid (DC-1) having a solid content concentration of 25 wt% and a colorant / resin (weight ratio) = 80 / 20.

[0335] <Preparation Example 3: Preparation of Photosensitive Colored Resin Composition 1> To 283.1 g of a colorant dispersion liquid (DC-1), 184.4 g of a 35 wt% solution of resin (A-13) in PGMEA, 50.1 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) as a polyfunctional monomer, 7.5 g of “Irgacure (registered trademark)” 907 (manufactured by BASF) and 3.8 g of “KAYACURE (registered trademark)” DETX-S (manufactured by Nippon Kayaku Co., Ltd.) as a photopolymerization initiator, 12.0 g of KBM5103 (manufactured by Shin-Etsu Chemical Co., Ltd.) as an adhesion improver, and a solution prepared by dissolving 3 g of a 10 wt% solution of silicone surfactant “BYK (registered trademark)” 333 (manufactured by BYK-Chemie) in PGMEA in 456.1 g of PGMEA were added to obtain a photosensitive colored resin composition 1 with a total solid content concentration of 20 wt% and a colorant / resin (weight ratio) = 30 / 70.

[0336] <Preparation Example 4: Production of Colorant Dispersion Liquid (DC-2)> According to the method described in JP-T-2008-517330, the surface element composition of carbon black (CB-Bk1) modified with sulfonic acid groups on the surface was (C: 88%, O: 7%, Na: 3%, S: 2%). As for the state of the S element, the components attributed to C-S and S-S among the S2p peak components were 90%, and the components attributed to SO and Sox were 10%. The BET value was 54 m2 / g.

[0337] 200 g of this carbon black CB-Bk1, 94 g of a 40 mass% solution of acrylic resin (A-13) in propylene glycol monomethyl ether acetate, 31 g of a 40 mass% solution of BYK-Japan LPN21116 as a polymer dispersant, and 675 g of propylene glycol monomethyl ether acetate were charged into a tank and stirred with a homomixer (manufactured by Tokushu Kika Co., Ltd.) for 1 hour to obtain a preliminary dispersion liquid. Then, the preliminary dispersion liquid was supplied to an Ultra Apex Mill (manufactured by Kotobuki Kogyo Co., Ltd.) equipped with a centrifugal separator filled with 70% of 0.05 mmφ zirconia beads (YTZ balls manufactured by Nikkato) and dispersed at a rotational speed of 8 m / s for 2 hours to obtain a colored dispersion liquid DC-2 with a solid content concentration of 25 mass% and a pigment / resin (mass ratio) = 80 / 20.

[0338] <Preparation Example 5: Preparation of Photosensitive Colored Resin Composition 2> To 534.8 g of a colorant dispersion liquid (DC-2), 122.1 g of a 40 mass% solution of resin (A-13) in PGMEA, 47.3 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) as a polyfunctional monomer, 11.8 g of "ADEKA Cure" NCI-831 (manufactured by ADEKA Corporation) as a photopolymerization initiator, 12.0 g of KBM5103 (manufactured by Shin-Etsu Chemical Co., Ltd.) as an adhesion improver, and a solution prepared by dissolving 4 g of a 10 mass% solution of silicone surfactant "BYK (registered trademark)" 333 (manufactured by BYK Chemie GmbH) in PGMEA in 194.0 g of PGMEA were added to obtain Photosensitive Colored Resin Composition 2 with a total solid content concentration of 25 mass% and a colorant / resin (weight ratio) = 45 / 55.

[0339] The components (A-9), (B-3), (C-1), (C-2), other components, and solvents used in the examples and comparative examples are shown below. (A-9) Phenolic resin MEHC-7851 (manufactured by Meiwa Kasei Co., Ltd.) (C-1) HMOM-TPHAP (manufactured by Honshu Chemical Industry Co., Ltd.) (C-2) YX4000H (manufactured by Mitsubishi Chemical Corporation

[0340] [Chemical formula]

[0341] (B-3): Photopolymerization initiator NCI-831 (manufactured by ADEKA Corporation) Other components: (F-1): Dipentaerythritol hexaacrylate (DPHA, manufactured by Kyoeisha Chemical Co., Ltd.)) (F-2): 2,4-Diethylthioxanthone (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.)) (F-3): 2,5-Bis(1,1,3,3-tetramethylbutyl)hydroquinone (DOHQ, manufactured by Wako Pure Chemical Industries, Ltd.)) Solvents: GBL: Gamma-butyrolactone PGMEA: Propylene Glycol Monomethyl Ether Acetate.

[0342] Table 1 shows the formulation of a resin composition composed of (A) resin, (B) photosensitizer, (C) thermal crosslinking agent, etc. Resin compositions 1-18 were prepared to have a solid content concentration of 40% by mass using the solvents described in Table 1. Further, Table 2-1 and Table 2-2 show the resin compositions used in the examples, the light transmittance (%) at a wavelength of 450 nm with a reference thickness of 5 μm of the cured film of the resin composition, the overall thickness (μm) of the cured film, the number of layers of the cured film, the shape and length of the opening pattern processed from the cured film, the presence or absence of step (D6) or step (E8), and the light extraction efficiency from the display device and the angle of the inclined side of the opening pattern.

[0343]

Table 1

[0344]

Table 2-1

[0345]

Table 2-2

[0346] Regarding evaluation level (1), those with a light extraction efficiency of the display device of 1.10 or more relative to Example 1 and a maximum length of the opening pattern of 5 μm or less are Level A, those with a light extraction efficiency of the display device of 1.00 or more relative to Example 1 and a maximum length of the opening pattern of 5 μm or less are Level B, those with a light extraction efficiency of the display device of 1.00 or more relative to Example 1 and a maximum length of the opening pattern greater than 5 μm and 20 μm or less are Level C, those with a light extraction efficiency of the display device of 1.00 or more relative to Example 1 and a maximum length of the opening pattern greater than 20 μm are Level D, and those with a light extraction efficiency of the display device of less than 1.00 relative to Example 1 are Level E.

[0347] Regarding the evaluation level (2), those with an inclined side angle of 55° or more and 80° or less were evaluated as level A, those with an angle of 40° or more and less than 55° or more than 80° and 85° or less were evaluated as level B, and those with an angle less than 40° or more than 85° were evaluated as level C.

[0348] (Example 1) (Configuration of FIG. 11) An example of the display device of the present invention will be described according to the cross-sectional view of the manufacturing process of FIG. 11. As shown in FIG. 11a, the support substrate 20 used a glass substrate. A temporary bonding material made of polyimide was disposed on the glass substrate, and the LED 2, which is a light-emitting element, was disposed on the support substrate 20 (corresponding to step (D1)). The thickness of the LED 2 was 7 μm, the length of one side was 30 μm, and the length of the other side was 50 μm.

[0349] Next, as shown in FIG. 11b, the resin composition 1 described in Table 1 was applied onto the support substrate 20 and the light-emitting element 2 so as to have a thickness of 10 μm after heat treatment, and the resin film 21 was formed (corresponding to step (D2)).

[0350] Next, as shown in FIG. 11c, i-line (365 nm) was irradiated through a mask having a desired pattern onto the resin film 21. The exposed resin film 21 was developed using a 2.38 mass% aqueous solution of tetramethylammonium (TMAH), and a plurality of opening patterns 12 penetrating in the thickness direction of the resin film 21 were pattern-formed (corresponding to step (D3)). The shape of the opening pattern was circular, and the longest length of the bottom surface portion in the smallest region among the opening patterns was 2 μm in diameter.

[0351] Next, after the resin film 21 was heat-treated at 110° C. for 30 minutes in an atmosphere with an oxygen concentration of 100 ppm or less, it was further heat-treated at 230° C. for 60 minutes to be cured, thereby forming a cured film 3 with a thickness of 10 μm (corresponding to step (D4)). The resin film 21 was directly cured to become the cured film 3.

[0352] Next, as shown in FIG. 11d, a titanium barrier metal was sputtered on the cured film 3, and a copper seed layer was further formed thereon by sputtering. After that, a photoresist layer was formed, and then, by an electroplating method, a metal wiring 4 made of copper electrically connected to the LED 2 was formed on the opening pattern 12 of the cured film 3 and a part of the surface of the cured film 3. Thereafter, the photoresist, the seed layer, and the barrier metal were removed (corresponding to step (D5)). The thickness of the metal wiring 4a formed on a part of the surface of the cured film 3 was 5 μm.

[0353] Thereafter, as shown in FIGS. 11e to f, steps (D2), (D3), (D4), and (D5) were repeated twice to form three layers of the cured film 3. As a result, the total thickness of the three layers of the cured film 3 was 30 μm. Thereafter, in FIG. 11g, a barrier metal 9 was formed in the opening pattern 12 of the cured film 3 by sputtering, and solder bumps 10 were formed. Thereafter, as shown in FIG. 11h, the solder was reflowed at 250° C. for 1 minute, and the light-emitting element driving substrate 7 having the driver IC which is the driving element 8d was electrically connected via the solder bumps 10. Thereafter, the support substrate 20 was peeled off, and the counter substrate 5 was bonded using an adhesive or the like to obtain a display device 1 having a plurality of LEDs 2.

[0354] (Example 2) The resin composition 1 of Example 1 was changed to a resin sheet made of the resin composition 2, and the resin film 21 was formed by lamination. The display device 2 was obtained in the same manner as in Example 1 except for this.

[0355] (Examples 3 to 11) The resin composition 1 of Example 1 was changed to the resin compositions 3 to 11, and the display devices 3 to 11 were obtained in the same manner as in Example 1 except for this.

[0356] (Example 12) The resin composition 1 of Example 1 was changed to the resin composition 12, and the display device 12 was obtained in the same manner as in Example 1 except that a photoresist was formed before exposure and the photoresist was removed after development.

[0357] (Example 13) Example 13 was carried out in the same manner as Example 2, except that after step (D3) and before step (D4), an i-line (365 nm) irradiation step (D6) was added to irradiate the entire area of the resin film 21 on which the aperture pattern 12 obtained in step (D3) was formed, and the display device 13 was obtained.

[0358] (Example 14) As shown in FIG. 12a, a partition wall 16 was formed on the support substrate 20 (corresponding to step D7). Next, as shown in FIG. 12b, an LED 2 was formed between the partition walls 16 (corresponding to step (D1)). Otherwise, the display device 14 was manufactured in the same steps as in Example 3. Note that the thickness of the LED 2 was 7 μm, and the thickness of the partition wall 16 was formed to be 10 μm. The partition wall 16 was made of an acrylic resin containing a known white pigment.

[0359] (Example 15) As shown in FIG. 13d, in the same manner as in Example 3, after the step (D4) of forming the cured film shown in FIG. 11c, aluminum was formed to a thickness of 0.2 μm by sputtering at a predetermined position so as to avoid the metal wiring 4 to be formed later, and the reflective film 15 was provided (step (D8)). Otherwise, the display device 15 was manufactured in the same steps as in Example 3.

[0360] (Example 16) An example of the display device of the present invention will be described according to the manufacturing process cross-sectional view of FIG. 14. First, as shown in FIG. 14a, an electrode pad 18 made of copper was disposed on the support substrate 20 (corresponding to step (E1)). The thickness of the electrode pad was 0.2 μm. Next, as shown in FIG. 14b, the resin composition 1 shown in Table 1 was applied onto the support substrate 20 and the metal pad 18 so as to have a thickness of 10 μm after heat treatment, and a resin film 21 was formed (corresponding to step (E2)). Next, as shown in FIG. 14c, a plurality of aperture patterns 12 were formed in the resin film 21 under the same conditions as the photolithography process shown in Example 1 (corresponding to step (E3)).

[0361] Next, the resin film 21 was cured under the same conditions as in Example 1 to form a cured film 3 with a thickness of 10 μm (corresponding to step (E4)). Subsequently, in FIG. 14c, in order to improve the adhesion between the cured film 3 and the metal wiring 4, a barrier metal such as titanium was sputtered on the cured film 3, and further, a copper seed (seed layer) was formed thereon by a sputtering method.

[0362] Next, as shown in FIG. 14d, after forming a photoresist layer, a metal wiring 4 made of copper was formed on the opening pattern 12 of the cured film 3 and on a part of the surface of the cured film 3 by an electroplating method (corresponding to step (E5)). The thickness of the metal wiring 4a formed on a part of the surface of the cured film 3 was 5 μm. Thereafter, the photoresist, the seed layer, and the barrier metal were removed.

[0363] Thereafter, steps (E2), (E3), (E4), and (E5) were repeated twice, and three cured films 3 each having a metal wiring 4 therein were formed as shown in FIG. 14e. As a result, the total thickness of the three cured films 3 was 30 μm.

[0364] Next, as shown in FIG. 14f, the LED 2 was disposed on the cured film 3 so as to maintain electrical connection with the metal wiring 4 (corresponding to step (E6)). The thickness of the LED 2 was 7 μm. Next, as shown in FIG. 14g, a resin film 21 made of the resin composition 1 was formed on the cured film 3 and the light-emitting element 2, and cured by heat treatment to form a cured film 3. Note that after heat treatment at 110° C. for 30 minutes in an atmosphere with an oxygen concentration of 100 ppm or less, heat treatment was further performed at 230° C. for 60 minutes to form the cured film 3. Next, as shown in FIG. 14h, the support substrate 20 was peeled off, a light-emitting element driving substrate 7 having a driver IC which is a driving element 8 was electrically connected via a solder bump 10, and a counter substrate 5 was bonded to the LED 2 using an adhesive or the like to obtain a display device 16 having a plurality of LEDs 2.

[0365] (Examples 17 to 18) The resin composition 1 of Example 16 was changed to resin compositions 2 to 3, and the same method as in Example 16 was performed to obtain display devices 17 to 18.

[0366] (Example 19) In Example 17, further, after step (E3) and before step (E4), a step (E8) of irradiating the entire area of the resin film 21 on which the aperture pattern 12 obtained in step (E3) was pattern-formed with i-line (365 nm) was added, and the same method as in Example 17 was performed to obtain a display device 19.

[0367] (Example 20) As shown in FIG. 15f, in the same manner as in Example 18, after forming a plurality of cured films 3 shown in FIG. 14e, a partition wall 16 was formed using the resin composition 3 between and around the LEDs 2 arranged later (corresponding to step (E9)). Thereafter, as shown in FIG. 15g, a plurality of LEDs 2 were arranged, and as shown in FIG. 15h, the support substrate 20 was peeled off, and a light-emitting element driving substrate 7 having a driver IC as the driving element 8 was electrically connected via the solder bump 10. Further, a counter substrate 5 was bonded to the LEDs 2 using an adhesive or the like to obtain a display device 20 having a plurality of LEDs 2. The thickness of the LED 2 was 7 μm, and the thickness of the partition wall was 10 μm.

[0368] (Example 21) As shown in FIG. 16f, after the step (E5) of forming the cured film shown in FIG. 14e in the same manner as in Example 18, aluminum was formed to a thickness of 0.5 μm by sputtering at a predetermined position so as to avoid the formed metal wiring 4, and a reflective film 15 was provided (corresponding to step (E10)). Thereafter, a display device 21 was manufactured in the same steps as in Example 18.

[0369] (Example 22) The resin composition 1 of Example 1 was changed to the resin composition 17, and the exposed resin film 21 was developed using cyclopentanone, and the same method as in Example 1 was performed to obtain a display device 26.

[0370] (Example 23) The resin composition 1 of Example 16 was changed to resin composition 17, and the exposed resin film 21 was developed using cyclopentanone in the same manner as in Example 16 to obtain a display device 27.

[0371] (Example 24) The resin composition 1 of Example 16 was changed to resin composition 18, and as shown in Fig. 14b, the resin composition 18 described in Table 1 was applied onto the support substrate 20 and the metal pad 18 so as to be 3 μm after heat treatment to form a resin film 21 (corresponding to step (E2)). Next, as shown in Fig. 14c, among the photolithography steps shown in Example 1, a plurality of opening patterns 12 were formed in the resin film 21 under the same conditions except that the developer was changed to an aqueous solution of 0.4 mass% tetramethylammonium (TMAH) (corresponding to step (E3)).

[0372] Next, the resin film 21 was cured under the same conditions as in Example 1 to form a cured film 3 with a thickness of 3 μm (corresponding to step (E4)).

[0373] Subsequently, in Fig. 14c, in order to improve the adhesion between the cured film 3 and the metal wiring 4, a barrier metal such as titanium was sputtered onto the cured film 3, and further, a copper seed (seed layer) was formed thereon by sputtering.

[0374] Next, as shown in Fig. 14d, after forming a photoresist layer, a metal wiring 4 made of copper was formed on the opening pattern 12 of the cured film 3 and a part of the surface of the cured film 3 by plating (corresponding to step (E5)). The thickness of the metal wiring 4a formed on a part of the surface of the cured film 3 was 1.5 μm. Thereafter, the photoresist, the seed layer, and the barrier metal were removed.

[0375] Thereafter, steps (E2), (E3), (E4), and (E5) were repeated twice, and as shown in Fig. 14e, three cured films 3 each having a metal wiring 4 therein were formed. As a result, the total thickness of the three cured films 3 was 9 μm.

[0376] Next, as shown in FIG. 14f, the LED 2 was placed on the cured film 3 so as to maintain an electrical connection with the metal wiring 4 (corresponding to step (E6)). The thickness of the LED 2 was 7 μm.

[0377] Next, as shown in FIG. 14g, a resin film 21 made of a resin composition 18 was formed on the cured film 3 and the light-emitting element 2, and was cured by heat treatment to form a cured film 3. Note that after heat treatment at 110° C. for 30 minutes in an atmosphere with an oxygen concentration of 100 ppm or less, heat treatment was further performed at 230° C. for 60 minutes to form the cured film 3.

[0378] Next, as shown in FIG. 14h, the support substrate 20 was peeled off, a light-emitting element driving substrate 7 having a driver IC which is a driving element 8 was electrically connected via solder bumps 10, and a counter substrate 5 was bonded to the LED 2 using an adhesive or the like, thereby obtaining a display device 28 having a plurality of LEDs 2.

[0379] (Example 25) The resin composition 1 of Example 1 was changed to a resin composition 3. As shown in FIG. 11h, grooves were formed by laser processing on the side surface of the light-emitting element driving substrate 7, titanium and copper were formed in this order by sputtering, and then copper was formed by electroplating to form a metal wiring 4c (corresponding to step D9). Otherwise, the same method as in Example 1 was used to obtain a display device 29.

[0380] (Example 26) The resin composition 1 of Example 16 was changed to a resin composition 3. As shown in FIG. 14h, grooves were formed by laser processing on the side surface of the light-emitting element driving substrate 7, titanium and copper were formed in this order by sputtering, and then copper was formed by electroplating to form a metal wiring 4c (corresponding to step E11). Otherwise, the same method as in Example 16 was used to obtain a display device 30.

[0381] (Example 27) On the side surface of the light-emitting element driving substrate 7 of Example 25, as shown in FIG. 24h, the conductive film 27 was used, and the photosensitive conductive paste 1 of Preparation Example 1 was used as the conductive film 27 (corresponding to Step D10). Otherwise, the same method as in Example 25 was performed to obtain the display device 31. The production of the conductive film 27 is as follows.

[0382] <Fabrication of Conductive Film 27> The photosensitive conductive paste 1 was applied onto a release PET film coated with a release agent on a PET film having a thickness of 16 μm so that the film thickness after drying would be 6.0 μm, and the obtained coating film was dried in a drying oven at 100 °C for 10 minutes. Thereafter, after exposing with an exposure amount of 350 mJ / cm 2 using an exposure machine having an ultra-high pressure mercury lamp, spray development was performed at a pressure of 0.1 MPa for 30 seconds using a 0.1 mass% aqueous sodium carbonate solution as a developer to obtain a pattern. Thereafter, the obtained pattern was cured in a drying oven at 140 °C for 30 minutes to obtain a transfer sample with wiring arranged. The line width of the obtained pattern was 50 μm, and the line length was 90 mm. The transfer sample was bonded to both sides so that a part of the wiring was arranged at the glass end having an R chamfer, the glass side surface was pressed against a hot plate at 130 °C for 30 seconds, and then the remaining part was transferred using a hot roll laminator under the conditions of 130 °C and 1.0 m / min.

[0383] (Example 28) On the side surface of the light-emitting element driving substrate 7 of Example 26, as shown in FIG. 24h, the conductive film 27 was used, and the photosensitive conductive paste 1 described in Example 27 was used as the conductive film 27 (corresponding to Step E12). Otherwise, the same method as in Example 26 was performed to obtain the display device 32.

[0384] (Example 29) A printed wiring board was used as the light-emitting element driving substrate 7 of Example 25, and the driving element 8 and the metal wiring 4 were connected through the wiring and bumps in the printed wiring board, and the same method as in Example 25 was performed to obtain the display device 33.

[0385] (Example 30) A printed wiring board was used as the light-emitting element driving substrate 7 of Example 26, and a display device 34 was obtained in the same manner as in Example 26, except that the driving element 8 and the metal wiring 4 were connected through the wirings and bumps in the printed wiring board.

[0386] (Example 31) As shown in Fig. 25a, a light-shielding layer 28 was formed on the support substrate 20 (corresponding to step D11). Next, as shown in Fig. 25a, LEDs 2 were formed between the light-shielding layers 28 (corresponding to step (D1)). Otherwise, a display device 35 was manufactured in the same steps as in Example 3. The production of the light-shielding layer 28 is as follows.

[0387] <Production of light-shielding layer 28> The colored resin composition 1 was applied to the support substrate 20 so as to have a thickness of 1 μm after heat treatment, and the coating film was heat-dried on a hot plate at 100 °C for 2 minutes. With respect to this dried film, using an exposure machine having an ultra-high pressure mercury lamp, ultraviolet rays were exposed at an exposure amount of 200 mJ / cm 2 . Next, development was carried out using an alkaline developer of a 0.045 wt% potassium hydroxide aqueous solution, and then pure water washing was performed to obtain a pattern film. The obtained pattern film was post-baked in a hot air oven at 230 °C for 30 minutes to obtain a light-shielding layer.

[0388] (Example 32) A display device 36 was manufactured in the same steps as in Example 31, except that the light-shielding layer 28 of Example 31 was changed to the colored resin composition 2 to form the light-shielding layer 28.

[0389] (Example 33) In Fig. 11f, a display device 37 was obtained in the same steps as in Example 3, except that the thickness of the metal wiring 4a in contact with the bump 10 was 10 μm, the thickness of the cured film 3 formed on a part of the surface of the metal wiring 4a was 15 μm, and the total thickness of the cured film 3 was 35 μm.

[0390] (Example 34) In FIG. 14b, a display device 38 was obtained in the same process as in Example 18, except that the thickness of the metal pad 18 was 10 μm, the thickness of the cured film 3 formed on a part of the surface of the metal pad was 15 μm, and the total thickness of the cured film 3 was 35 μm.

[0391] (Example 35) Example 35 of the display device of the present invention will be described according to the manufacturing process cross-sectional view of FIG. 27. As shown in FIG. 27a, as the light-emitting element driving substrate 7, a TFT array substrate was used, and the resin composition 3 described in Table 1 was applied on the light-emitting element driving substrate 7 so as to have a thickness of 3 μm after heat treatment to form a resin film 21 (corresponding to step (F1)). The thickness of the metal wiring 4 was 1 μm. Next, a plurality of opening patterns 12 were formed in the resin film 21 under the same conditions as in the photolithography process shown in Example 3 (corresponding to step (F2)).

[0392] Next, the resin film 21 was cured under the same conditions as in Example 3 to form a cured film 3 having a thickness of 3 μm (corresponding to step (F3)).

[0393] Next, as shown in FIG. 27b, in the step of forming the wiring or the conductive film on at least a part of the surface of the cured film and a part of the opening pattern of the cured film. After forming a photoresist layer (not shown), ITO was formed as the wiring 25 on a part of the surface of the cured film 3 by a sputtering method. Then, unnecessary photoresist was removed. (Corresponding to step (F4)). The thickness of the ITO was 0.1 μm.

[0394] Next, as shown in FIG. 27c, steps (F1), (F2), and (F3) were repeated to cure the resin composition 3 described in Table 1 to form a cured film 3 having a thickness of 2 μm.

[0395] Next, as shown in Fig. 27d, a cured film 3 or a partition wall 16 was formed thereon. Next, as shown in Fig. 12b, an LED 2 was formed between the partition walls 16 (corresponding to step (F5)). Note that the thickness of the LED 2 was 7 μm, and the thickness of the partition wall 16 was formed to be 8 μm. The partition wall 16 was made of an acrylic resin containing a known white pigment.

[0396] Thereafter, as shown in Fig. 27e, the opposing substrate 5 was bonded using an adhesive. Also, a conductive film 27 formed using the photosensitive conductive paste 1 of Preparation Example 1 as the conductive film 27 was formed, and a driving element 8 such as a driver IC was electrically connected to the light-emitting element 2 through the conductive film 27 via the metal wiring 4 and the wiring 25 extending in the cured film 3, thereby obtaining a display device 39 having a plurality of LEDs 2. As a result, in the display devices 1 to 21, 26 to 39, since the light transmittance of the cured film 3 was high, the light extraction efficiency was improved and the luminance was improved. Also, compared with the conventional flexible substrate, since the thickness of the cured film was small, it was possible to suppress wiring defects such as short circuits of the wiring due to the reduction in package height and the shortening of the wiring distance, to reduce losses, and to improve the high-speed responsiveness. Furthermore, in the display devices 1 to 11, 13 to 21, 26 to 39, since microfabrication was possible, minute light-emitting elements could be applied, and high-density mounting of the light-emitting elements was possible. Also, a cured film made of a resin composition was applicable as the partition wall 16, and by forming the partition wall, the bonding of the opposing substrate was facilitated. Furthermore, in the display devices 1 to 21, 26 to 32, 35 to 39, since at least a part of the metal wiring or the conductive film extended to the side surface of the substrate, the reduction in height and the high-speed responsiveness of the display device itself were improved, and the display device could be made smaller and have a narrower bezel. Also, in the display devices 35, 36, by forming a light-shielding layer between the plurality of light-emitting elements, it was possible to suppress light leakage from the light-emitting elements and color mixing between the pixels without significantly impairing the light extraction efficiency, and to improve the contrast. In the display devices 37, 38, since the thickness of the metal wiring close to the bump 10 was thicker than the thickness of the metal wiring close to the LED 2, wiring defects could be suppressed when connecting the light-emitting element driving substrate 7 using the bump 10, and a highly reliable display device could be obtained.

[0397] (Comparative Examples 1, 3 to 4) The resin composition 1 of Example 1 was changed to resin compositions 13, 15 to 16, and the same method as in Example 1 was performed to obtain display devices 22, 24 to 25.

[0398] (Comparative Example 2) The resin composition 1 of Example 1 was changed to resin composition 14, and the exposed resin film 21 was developed using cyclopentanone, and the same method as in Example 1 was performed to obtain display device 23.

[0399] As a result, for display devices 22 to 25, since the light transmittance of the cured film 3 was low, the light extraction efficiency was not achieved and the luminance was also not achieved.

Explanation of Reference Numerals

[0400] 1 Display device 2 Light-emitting element 3 Cured film 4, 4c Metal wiring 4a Thickness of the metal wiring disposed on the surface of the cured film 4b Thickness of the metal wiring extending to the opening pattern penetrating in the thickness direction in the cured film 5 Counter substrate 6 Electrode terminal 7 Light-emitting element driving substrate 8 Driving element 9 Barrier metal 10 Solder bump 11a Designated region A 11b Designated region B 12 Opening pattern 13 Bottom surface portion of the metal wiring 4 14 Longest length of the bottom surface portion 15 Reflective film 16 Partition wall 17 External substrate 18 Metal pad 19 Total thickness of the cured film 20 Support substrate 21 Resin film 22 Cured film 23 TFT 24 TFT insulating layer 25 Wiring 26 Contact hole 27 Conductive film 28 Light-shielding layer 29 Inclined side 30 Angle of the inclined side 31 Thickness of the cured film 3 32 Position at half of the thickness of the effect film 3

Claims

1. A display device having at least a metal wiring, a cured film, and a plurality of light-emitting elements, wherein each of the light-emitting elements includes a pair of electrode terminals on one surface thereof, the pair of electrode terminals are connected to a plurality of the metal wirings extending in the cured film, and the plurality of the metal wirings are configured to maintain electrical insulation by the cured film, the cured film is a film obtained by curing a resin composition containing at least one resin selected from the group consisting of (A) polyimide, a polyimide precursor, polybenzoxazole, a polybenzoxazole precursor, a copolymer thereof, an acrylic resin, a phenol resin, and a cardo resin, A display device, wherein the transmittance of light with a wavelength of 450 nm at a reference thickness of 5 μm of the cured film is 80% or more and 100% or less.

2. The display device according to claim 1, wherein the total thickness of the cured film is 5 to 100 μm.

3. The display device according to claim 1 or 2, wherein the number of layers of the cured film is 2 or more and 10 or less.

4. The cured film is provided with an opening pattern penetrating in the thickness direction, and at least the metal wiring is disposed in the opening pattern, and the longest length of the bottom surface portion of the metal wiring formed at a position in contact with the light-emitting element is 2 to 20 μm. The display device according to any one of claims 1 to 3.

5. The display device according to any one of claims 1 to 4, wherein the cured film covers a surface other than the light extraction surface of the light-emitting element.

6. The display device according to any one of claims 1 to 5, wherein a reflective film is further provided on the cured film.

7. The display device according to any one of claims 1 to 6, having a partition wall having a thickness equal to or greater than the thickness of the light-emitting element between a plurality of the light-emitting elements.

8. The display device according to any one of claims 1 to 7, wherein a partition wall having a thickness equal to or greater than the thickness of the light-emitting element is disposed in the cured film covering the light-emitting element between a plurality of the light-emitting elements.

9. The display device according to any one of claims 1 to 8, wherein the light-emitting element is an LED having a side length of 5 μm or more and 700 μm or less.

10. Furthermore, having a driving element and a substrate, the driving element is connected to the light-emitting element through a metal wiring, and at least a part of the metal wiring extends to the side surface of the substrate. The display device according to any one of claims 1 to 9.

11. The display device according to any one of claims 1 to 10, having a light-shielding layer between a plurality of the light-emitting elements.

12. The display device according to any one of claims 1 to 11, wherein the resin (A) contains one or more resins selected from the group consisting of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, and copolymers thereof.

13. The display device according to any one of claims 1 to 12, wherein the resin composition containing the resin (A) further contains a photosensitive agent (B).

14. The display device according to any one of claims 1 to 13, wherein the resin composition containing the resin (A) further contains a thermal crosslinking agent (C).

15. The display device according to any one of claims 1 to 14, wherein the resin composition containing the resin (A) is positive photosensitive.

16. A method for manufacturing a display device having at least a metal wiring, a cured film, and a plurality of light-emitting elements, comprising: a step (D1) of disposing the light-emitting element on a support substrate; a step (D2) of forming a resin film made of a resin composition containing one or more resins selected from the group consisting of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, copolymers thereof, acrylic resin, phenolic resin, and cardo resin on the support substrate and on the light-emitting element; a step (D3) of forming a plurality of through-opening patterns in the resin film by exposing and developing the resin film; a step (D4) of curing the resin film to form a cured film having a light transmittance of 80% or more and 100% or less at a wavelength of 450 nm with a thickness reference of 5 μm; and a step (D5) of forming the metal wiring on at least a part of the surface of the cured film and in the opening pattern of the cured film. A method for manufacturing a display device having the above steps.

17. The method for manufacturing a display device according to claim 16, further comprising a step (D6) of exposing the entire area of the resin film after the step (D3) and before the step (D4).

18. The method for manufacturing a display device according to claim 16 or 17, further comprising a step of repeatedly performing the steps (D2), (D3), (D4), and (D5) a plurality of times to form a plurality of layers of the cured film having the metal wiring in the cured film.

19. The method for manufacturing a display device according to any one of claims 16 to 18, further comprising a step (D7) of providing a partition wall having a thickness equal to or greater than the thickness of the light-emitting element before the step (D1).

20. The method for manufacturing a display device according to any one of claims 16 to 19, having a step (D8) of providing a reflective film on a part of the cured film after the step (D4).

21. A method for manufacturing a display device having at least a metal wiring, a cured film, and a plurality of light-emitting elements, a step (E1) of disposing metal pads on a support substrate, a step (E2) of forming a resin film made of a resin composition containing at least one resin selected from the group consisting of (A) polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, their copolymers, acrylic resin, phenolic resin, and cardo resin on the support substrate and on the metal pads, a step (E3) of forming a plurality of through-opening patterns in the resin film by exposing and developing the resin film, a step (E4) of curing the resin film to form the cured film having a light transmittance of 80% or more and 100% or less at a wavelength of 450 nm with a thickness reference of 5 μm, a step (E5) of forming the metal wiring on at least a part of the surface of the cured film and in the opening patterns of the cured film, a step (E6) of disposing the light-emitting elements on the cured film while maintaining electrical connection with the metal wiring, The method for manufacturing a display device having these steps.

22. The method for manufacturing a display device according to claim 21, having a step (E8) of exposing the entire area of the resin layer after the step (E3) and before the step (E4).

23. The method for manufacturing a display device according to any one of claims 21 or 22, having a step of repeatedly performing the steps (E2), (E3), (E4), and (E5) a plurality of times to form a plurality of layers of the cured film having the metal wiring in the cured film.

24. The method for manufacturing a display device according to any one of claims 21 to 23, having a step (E9) of providing a partition wall having a thickness equal to or greater than the thickness of the light-emitting element after the step (E5).

25. The method for manufacturing a display device according to any one of claims 21 to 24, having a step (E10) of providing a reflective film on a part of the cured film after the step (E5) and before the step (E6).

Images