Color conversion substrate and display device

Abstract

To provide a color conversion substrate in which a partition pattern is formed with high dimensional accuracy even in a height of approximately several tens μm.SOLUTION: A color conversion substrate 200 includes: a transparent substrate 10; a color filter part 11 having a lattice-like black matrix 2 having an opening and a color filter arranged in the opening; and a wavelength conversion part 12 including a reflective partition wall 5 provided so as to overlap with the black matrix on the color filter part, and a wavelength conversion layer provided in the opening of the reflective partition wall. The color filter includes at least one of a red filter 1R, a green filter 1G and a yellow filter. The reflective partition wall has a first pillar 7a formed of a transparent resin in a lattice shape, and a metal thin film 8 provided on the first pillar. The reflective partition wall further has a second pillar 7b which is arranged at a position not overlapping with any one of the red filter, the green filter and the yellow filter in plan view, and the first pillar and the second pillar are integrally continuous in at least a lower part.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a color conversion substrate. A display device using this color conversion substrate will also be mentioned.

Background Art

[0002] In recent years, the development of self-emitting display devices such as micro LED (Light Emitting Diode) displays and organic electroluminescence (hereinafter also referred to as "organic EL") display devices has been booming. A micro LED display has a structure in which LED elements with a size of approximately 2 μm to 50 μm are arranged in a matrix, and display is performed by individually driving each of a plurality of LED elements. Since such a self-emitting display device can perform display without using liquid crystal as a display function layer that switches light transmission / non-transmission, it has been a problem that light leakage occurs during black display, compared with a liquid crystal display device, it is particularly excellent in visibility in a dark place.

[0003] Some of the prior arts in this field are shown. In Patent Document 1, the wavelength of light (ultraviolet light) emitted from a light-emitting element is converted by a color conversion layer composed of Blue, Green, and Red. Each color conversion layer is partitioned by a black matrix.

[0004] In Patent Document 1, the thickness, optical density, and specific formation method of the black matrix are not specified. When forming a black matrix with an optical density of around 4 and a thickness of about 10 μm, in a well-known photolithography technique including an exposure / development process, since the exposure light hardly penetrates in the thickness direction, it is difficult to maintain the dimensional accuracy of the formed black matrix.

[0005] In Patent Document 1, wavelength conversion is performed by a so-called color filter. As another configuration example, Patent Document 2 discloses a full-color LED display panel in which an LED that emits light in the wavelength band from ultraviolet to blue is used as a light source, and a fluorescent emission layer is stacked on the LED light source for wavelength conversion.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] When manufacturing a display device as described in Patent Document 1 using the prior art, after forming a light-scattering or light-blocking partition pattern having openings with a thickness of several tens of μm, a color conversion layer composed of one color out of a plurality of predetermined colors is patterned in the openings. If the light-emitting element is a blue LED, since the Blue pixel can use the color of the light source as it is for display, instead of the color conversion layer, a transparent resin can be filled and patterned. Here, when coating a partition pattern having a height of several tens of μm with a resin for a conversion layer or a transparent resin with a height of several tens of μm and patterning it by photolithography, air may be trapped in the openings, causing color bleeding, or resin that should originally be dissolved by development may remain at the bottom of the openings, causing color mixing.

[0008] The thickness of the color conversion layer is determined by the content of the phosphor material in the color conversion resin and the luminous efficiency, but often requires an optical path length of 3 μm or more and 30 μm or less. To fill a phosphor material of such a thickness, a partition pattern also requires a height of several tens of μm. However, it is difficult to sufficiently expose a coating film with a thickness of several tens of μm from the top to the bottom by exposure using photolithography for a light-scattering film in which TiO2 particles or the like are dispersed or a light-shielding film in which carbon black is dispersed. As a result, when a positive resist is used, the pixel opening is at the position where it is exposed, and a phenomenon occurs in which a residual film remains in the pixel opening. Further, when a negative resist is used, while the central portion of the partition pattern becomes thick due to scattered light, the lower portion becomes thin due to insufficient exposure. Therefore, it is difficult to form the partition pattern with a uniform dimension from the top to the bottom.

[0009] In view of the above circumstances, an object of the present invention is to provide a color conversion substrate in which a partition pattern is formed with high dimensional accuracy even at a height of about several tens of μm.

Means for Solving the Problems

[0010] A first aspect of the present invention is a color conversion substrate including a color filter portion having a transparent substrate, a lattice-shaped black matrix provided on the transparent substrate and having an opening, and a color filter disposed in the opening, and a wavelength conversion portion 12 including a reflective partition provided on the color filter portion so as to overlap the black matrix in plan view and a wavelength conversion layer provided in the opening of the reflective partition. The color filter includes at least one of a red filter, a green filter, and a yellow filter. The reflective partition has a first pillar formed in a lattice shape with a transparent resin and a metal thin film provided on the first pillar. Furthermore, it has a second pillar formed of a transparent resin and disposed at a position that does not overlap any of the red filter, the green filter, and the yellow filter in plan view, and the first pillar and the second pillar are integrally continuous at least at the lower portion on the color filter portion side.

[0011] A second aspect of the present invention is a display device including the color conversion substrate according to the first aspect and a light module substrate in which a plurality of light-emitting elements that emit blue light are disposed on one surface and are bonded to the color conversion substrate via an adhesive layer so that the light-emitting elements and the wavelength conversion portion face each other.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a color conversion substrate on which a partition pattern is formed with high dimensional accuracy even at a height of about several tens of μm.

Brief Description of the Drawings

[0013]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Embodiments for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7. In the following description, the same or substantially the same functions and components are denoted by the same reference numerals, and the description thereof is omitted or simplified, or described only when necessary.

[0015] In this specification, "plan view" means a state in which a surface of a display device, a wavelength conversion substrate, etc., to be described later is viewed by an observer in the normal direction. Also, both "height" and "thickness" mean dimensions in a direction perpendicular to a surface such as a substrate surface, and are substantially synonymous. Ordinal numbers such as "first" and "second" in each configuration are attached to avoid confusion of components and do not specify order or quantity.

[0016] FIG. 1 is a schematic cross-sectional view of a display device 100 according to the present embodiment, and FIG. 2 shows the display device 100 disassembled. As shown in FIG. 2, the display device 100 has a configuration in which a color conversion substrate 200 and an optical module substrate 203 are joined by an adhesive layer 201.

[0017] The color conversion substrate 200 has a configuration in which a color filter portion 11, a planarization layer 3, and a wavelength conversion portion 12 are sequentially laminated on a transparent substrate 10. As the transparent substrate 10, substrates made of various transparent materials such as glass substrates, quartz substrates, sapphire substrates, and plastic substrates including polyimide films can be used.

[0018] The color filter portion 11 has a plurality of color filters and a black matrix 2 that partitions each color filter in a plan view. In the present embodiment, three color filters, a red filter 1R, a green filter 1G, and a blue filter 1B, are used, but the number and combination of color filters can be appropriately set according to applications and the like, and other colors such as yellow may be used. The method for forming the black matrix 2 is not particularly limited, but it can be easily formed using an alkali-soluble photosensitive resist in which light-shielding carbon is dispersed.

[0019] The planarization layer 3 is a layer for absorbing the height differences in each component of the color filter portion 11 and can be formed of a transparent resin.

[0020] The wavelength conversion portion 12 has a plurality of wavelength conversion layers and a reflective partition wall 5 that partitions each color filter in a plan view. In the present embodiment, two wavelength conversion layers, a red conversion layer 6R and a green conversion layer 6G, are used, but the number and combination of wavelength conversion layers can be appropriately set according to applications and the like. The red conversion layer 6R has a structure in which a phosphor that emits red fluorescence upon excitation light of a predetermined wavelength is dispersed in a base resin. The green conversion layer 6G has a structure in which a phosphor that emits green fluorescence upon excitation light of a predetermined wavelength is dispersed in a base resin. In each wavelength conversion layer, not only phosphor particles such as phosphate phosphors and nitride phosphors but also quantum dot phosphors can be used. It is convenient to use a color conversion particle-dispersed organic resin in which these color conversion particles are dispersed.

[0021] The reflective partition 5 has a pillar formed of a transparent resin and a metal thin film 8 provided on the pillar. The height of the reflective partition 5 can be, for example, 3 μm or more and 40 μm or less. As the material of the metal thin film 8, it is preferably sputterable, and examples thereof include aluminum alone and alloys containing aluminum. More specifically, high melting point metals such as Mo and Ti, or aluminum alloys to which a small amount of rare earths such as Nd (neodymium) is added can be mentioned. From the viewpoint of reflectance, an aluminum alloy containing 0.2 mass% or more and 3 mass% or less of Nd (the balance being inevitable impurities) is preferable. When Nd is less than 0.2 mass%, the crystals of aluminum tend to coarsen or hillocks are formed, so that the reflectance tends to decrease. Also, when Nd exceeds 3 mass%, the reflectance tends to decrease. When Nd is in the range of 0.2 mass% or more and 3 mass% or less, it is easy to stably exhibit a high reflectance. A metal thin film made of aluminum alone or an alloy of aluminum and neodymium exhibits excellent reflection characteristics with a reflectance of 85% or more and 99.5% or less for light having a wavelength of 400 nm or more and 700 nm or less. When the metal thin film 8 has a two-layer structure by providing a titanium layer between the above-described material and the pillar, there is an advantage that the adhesion to the pillar is improved and peeling or the like in the manufacturing process can be suppressed.

[0022] In this embodiment, two types of pillars, a first pillar 7a and a second pillar 7b, are provided. The first pillar 7a has a substantially lattice shape that generally overlaps with the black matrix 2 in a plan view of the color conversion substrate 200. The second pillar 7b has a substantially quadrangular prism shape that generally overlaps with the blue filter 1B in a plan view of the color conversion substrate 200, and fills a portion of the lattice-shaped opening of the first pillar 7a that overlaps with the blue filter 1B in a plan view. The second pillar 7b and the first pillar 7a located around it are integrally continuous in the entire thickness direction from the lower end to the upper end on the side of the flattening layer 3.

[0023] The metal thin film 8 covers the outer surface of the first pillar 7a protruding from the color filter portion 11, except for the portion integrally formed with the second pillar 7b. With such an arrangement, the metal thin film 8 is in a positional relationship that generally overlaps with the black matrix 2 in a plan view of the color conversion substrate 200.

[0024] An example of the manufacturing procedure of the color conversion substrate according to this embodiment configured as described above will be described. First, as shown in FIG. 3, a color filter portion 11 and a flattening layer 3 are formed on the transparent substrate 10 (step A). Each color filter and the black matrix of the color filter portion 11 can be formed using known photolithography.

[0025] Next, as shown in FIG. 4, the first pillar 7a and the second pillar 7b are integrally formed by photolithography using a photosensitive resin on the flattening layer 3 (step B). Since the first pillar 7a and the second pillar 7b are transparent, the light beam irradiated for curing reaches a portion closer to the flattening layer 3 sufficiently compared to a material colored by containing carbon or the like. As a result, it can be formed with much higher dimensional accuracy compared to the case where a light-absorbing partition wall is provided with a colored material. Examples of the photosensitive resin used in Step B include resins obtained by reacting a linear polymer having reactive substituents such as a hydroxyl group, a carboxyl group, and an amino group with a (meth)acrylic compound or cinnamic acid having reactive substituents such as an isocyanate group, an aldehyde group, and an epoxy group to introduce a photocrosslinkable group such as a (meth)acryloyl group or a styryl group into the linear polymer.

[0026] Although the first pillar 7a and the second pillar 7b are formed with high dimensional accuracy, they are transparent and thus do not function as a partition for preventing stray light and color mixing as they are. Therefore, a metal thin film 8 is formed on the outer surface of the pillar (Step C). First, a metal thin film is formed on the entire surface where the first pillar 7a and the second pillar 7b are provided by sputtering. After covering the top surface and the side surfaces of the first pillar 7a with a protective pattern such as a resist and then performing etching, the metal thin film not covered by the protective pattern is removed. Finally, when the protective pattern is peeled off, as shown in FIG. 5, a large amount of the metal thin film 8 is formed on the top surface and the side surfaces of the first pillar 7a, and the reflective partition 5 is completed.

[0027] Finally, when a red conversion layer 6R is formed in the opening of the reflective partition 5 corresponding to the red filter 1R and a green conversion layer 6G is formed in the opening of the reflective partition 5 corresponding to the green filter 1G, the color conversion substrate 200 of the present embodiment is completed (Step D). The red conversion layer 6R and the green conversion layer 6G may be formed in any order. In Step D, the wavelength conversion layer such as the red conversion layer 6R may be formed lower than the reflective partition. By doing so, it is possible to suppress the material of the wavelength conversion layer from overlapping the reflective partition and causing variations in the luminance of the display device.

[0028] When the optical module substrate 203 is bonded to the surface on the wavelength conversion unit 12 side of the completed color conversion substrate 200 via the adhesive layer 201, the display device 100 is completed. The optical module substrate 203 has a known basic structure in which a plurality of LEDs 202 are arranged in a matrix on the substrate 20. In the completed display device 100, at least one LED 202 is located within the range of each color filter in a plan view.

[0029] In this embodiment, the LED 202 is a blue light-emitting diode to which gallium nitride (GaN) or the like is applied. Either a mini-LED with a size of 50 μm to 200 μm or a micro-LED with a size of 2 μm to 50 μm can be used as the LED 202, and it can be appropriately selected in consideration of the planar view dimensions of the color filters of the color filter section 11 and the like. There is no particular limitation on the element structure of the LED 202, and either a horizontal LED in which the n-side electrode and the p-side electrode are on the same side or a vertical LED in which the n-side electrode and the p-side electrode sandwich the light-emitting section in the thickness direction can be used.

[0030] As the substrate 20, the same one as the transparent substrate 10 of the color conversion substrate can be used, but it does not necessarily have to be transparent, and a known silicon substrate or the like may be used. From the viewpoint of preventing the shift in the plan view (pixel shift) between the LED and the color filter that occurs during the bonding of the color conversion substrate 200, it is preferable that the coefficient of thermal expansion of the material of the substrate 20 is close to that of the transparent substrate 10. Each LED 202 is electrically connected to wiring (not shown) formed on the substrate 20 and can be driven through the substrate 20. There is no particular limitation on the connection method between the LED 202 and the wiring of the substrate 20, and various known methods such as flip-chip mounting using a low-melting-point alloy, mounting using an anisotropic conductive film, and wire bonding using a gold wire or the like can be applied.

[0031] The thickness of the adhesive layer 201 can be appropriately determined in consideration of the dimensions of the LED 202 and the like, and it is preferably equal to or greater than the thickness of the LED 202. There is no particular limitation on the material of the adhesive layer 201, but it preferably has a light transmittance such that 70% or more of the light emitted by the LED is transmitted at the set thickness, and more preferably has a light transmittance such that 85% or more is transmitted.

[0032] As shown in FIG. 2, on the optical module substrate 203, an auxiliary pattern 204 having substantially the same planar shape as the first pillar may be formed around the LED 202. The auxiliary pattern 204 is not an essential component, but by making the auxiliary pattern 204 have the same height as the LED 202, the color conversion substrate 200 and the optical module substrate 203 can be joined more stably. Further, by imparting absorbency to the auxiliary pattern 204, for example, by making it black, stray light and the like generated before the light of the LED enters the wavelength conversion unit 12 can be reduced.

[0033] The operation during use of the display device 100 will be described. In the display device 100, a full-color image or the like can be displayed on the color conversion substrate 200 side by independently turning on and off a large number of LEDs 202 arranged on the optical module substrate. When the LED 202 that overlaps with the red filter 1R in plan view emits light, the emitted blue light first enters the red conversion layer 6R. As a result, red fluorescence around a wavelength of 630 nm is emitted from the red conversion layer 6R and enters the red filter 1R, and is visually recognized as red light with its wavelength adjusted. Similarly, when the LED 202 that overlaps with the green filter 1G in plan view emits light, the emitted blue light first enters the green conversion layer 6G. As a result, green fluorescence around a wavelength of 535 nm is emitted from the green conversion layer 6G and enters the green filter 1G, and is visually recognized as green light with its wavelength adjusted.

[0034] On the other hand, when the LED 202 that overlaps with the blue filter 1B in plan view emits light, the emitted blue light enters the second pillar 7b from the top surface of the second pillar 7b and into the second pillar 7b. Since the second pillar 7b is transparent, the blue light directly enters the blue filter 1B and is visually recognized as blue light with its wavelength adjusted. In this way, even with an optical module substrate on which only one type of LED is arranged, by using the color conversion substrate 200 according to the present embodiment, a display device capable of full-color display can be configured.

[0035] The metal thin film 8 of the reflective partition reflects the light of the LED that has entered the wavelength conversion section and travels toward the adjacent color filter region, preventing the occurrence of color mixing and making it available as display light. The light incident on the red conversion layer 6R and the green conversion layer 6G is reflected by the metal thin film 8 provided on the side surface of the first pillar 7a. The light incident into the second pillar 7b passes through the surrounding first pillar 7a from within the second pillar 7b, hits the metal thin film 8 from the inside of the first pillar 7a, and is reflected. With the increasing high definition of LED displays, in display devices such as LED displays, the area ratio of the black matrix to the aperture area functioning as a pixel tends to increase. With the high definition of 600 ppi (pixels per inch), 800 ppi, and even 1000 ppi or more, the black matrix area ratio exceeds 60% and in some cases exceeds 70%, and accordingly the aperture area ratio decreases. Therefore, from the viewpoint of increasing the output of the display light, it is desirable that the reflectance of the metal thin film 8 be high. Even if the reflectance is lower than 85%, it is possible to output the display light to the viewing side, but there are cases where the display becomes dark, which is not preferable.

[0036] In the color conversion substrate according to this embodiment, by forming a metal thin film on the surface of a transparent lattice-shaped pillar, it functions as a reflective partition 5. Furthermore, paying attention to the fact that when the light source emits blue light, the resin layer filled in the opening of the pillar overlapping the blue filter 1B in plan view does not necessarily have to have a wavelength conversion function, the resin layer filled in the opening overlapping the blue filter 1B in plan view is used as the second pillar 7b and is integrally formed with the lattice-shaped first pillar 7a located around it. Thereby, the second pillar 7b overlapping the blue filter 1B in plan view and the first pillar 7a located around it are integrally continuous in the entire thickness direction from the lower end portion to the upper end on the flat layer side.

[0037] In the conventional configuration, since it is necessary to form a wavelength conversion layer in the opening of the pillar that overlaps with each color filter after forming the grid-shaped pillars, when there are three color filters, three steps are required. However, in the color conversion substrate according to this embodiment, by forming the first pillar 7a and the second pillar 7b, the step of forming a resin layer in the opening that overlaps with the blue filter 1B can be omitted. On the other hand, since the first pillar 7a and the second pillar 7b can be formed simultaneously in a single process by changing the mask, the number of steps does not increase in the pillar formation process. As a result, the manufacturing efficiency of the color conversion substrate 200 according to this embodiment is significantly improved compared to the prior art.

[0038] In addition, since the first pillar and the second pillar that define the basic shape of the reflective partition are formed of a transparent photosensitive resin, even when the thickness of the wavelength conversion part is relatively thick at several tens of μm, the resin material can be sufficiently exposed and developed, and a reflective partition with high dimensional accuracy can be formed. By integrally forming the second pillar 7b disposed in the opening of the pillar that overlaps with the blue filter 1B and the grid-shaped first pillar 7a located around it, it becomes impossible to form a metal thin film on the side surface of the first pillar on the opening side that overlaps with the blue filter 1B. However, as described above, since the metal thin film 8 provided on the surface on the side of the other adjacent color filter reflects the light that has entered from inside the second pillar into the first pillar, as a whole reflective partition 5, even in the opening of the pillar that overlaps with the blue filter 1B, stray light and the occurrence of color mixing associated therewith can be preferably suppressed.

[0039] In this embodiment, the shape of the second pillar can be changed in various ways. The second pillar 17b in the modification shown in FIG. 6 is lower than the first pillar 7a. By doing so, when the optical module substrate is bonded, the volume of the LED protruding from the optical module substrate can be partially absorbed by the step between the first pillar 7a and the second pillar 17b, so that the bonding state via the adhesive layer can be stabilized. The second pillar 17b can be easily realized in the above step B, for example, by forming the second pillar using a halftone mask. The wavelength conversion layer such as the red conversion layer 6R may be formed to have a shape lower than that of the reflective partition wall by the same method. In this case, in addition to stable joining, the overlap of the wavelength conversion layer material on the reflective partition wall can be reduced, and the gap control when joining the optical module substrate can be facilitated.

[0040] The second pillar 27b of the modified example shown in FIG. 7 has a groove 28 formed at the periphery of the top surface. In this way, the metal thin film 8 can also be provided on the inner surface of the groove 28 by sputtering or the like, and the effect of suppressing stray light or the like can be improved. The groove 28 can be formed relatively easily by setting the mask in step B. Also in this modified example, the second pillar and the first pillar located around it are integrally continuous in a certain thickness range from the lower end portion on the flat layer side.

[0041] The color conversion substrate according to the present invention will be further described using examples. The present invention is not limited by only the specific contents of the examples.

[0042] (Example 1) As the transparent substrate 10, a low-expansion glass with a thickness of 0.5 mm and a thermal expansion coefficient of 3 ppm / °C was used. A two-dimensional matrix-shaped black matrix 2 having an opening was formed on one surface of this glass. Further, a red filter 1R (near the peak wavelength of 630 nm), a green filter 1G (near the peak wavelength of 535 nm), and a blue filter 1B (near the peak wavelength of 430 nm) were provided in the opening of the black matrix to form a color filter portion 11. Subsequently, a planarization layer 3 was formed of a siloxane-based transparent resin to cover the color filter portion 11.

[0043] Next, a negative-type photosensitive transparent resin made of an acrylic resin was coated on the planarization layer 3, and the first pillar 7a and the second pillar 7b with a thickness of 15 μm were integrally formed by photolithography. The first pillar 7a and the second pillar 7b are continuous in a plan view.

[0044] Next, an aluminum layer with a thickness of 100 nm was formed by sputtering on the surface where the first pillar 7a and the second pillar 7b were formed, and then it was coated with a novolak-based positive photosensitive resin. This photosensitive resin was patterned by photolithography to form a protective pattern covering only the portion to be left as the metal thin film 8. Furthermore, etching was performed using a weakly acidic etching solution. After removing the aluminum layer not covered by the protective pattern, the protective pattern was peeled off to form the reflective partition wall 5.

[0045] Next, a green conversion layer 6G with a thickness of 13 μm was formed in the opening of the reflective partition wall that overlapped with the green filter 1G in plan view. The green conversion layer 6G has a structure in which phosphor particles that convert the light source of the blue LED into light having a peak around a wavelength of 535 nm are dispersed and arranged in a transparent base resin. Furthermore, a red conversion layer 6R with a thickness of 13 μm was formed in the opening of the reflective partition wall that overlapped with the red filter 1R in plan view. The red conversion layer 6R has a structure in which phosphor particles that convert the light source of the blue LED into light having a peak around a wavelength of 630 nm are dispersed and arranged in a transparent base resin.

[0046] Thus, the color conversion substrate according to Example 1 was manufactured. In the color conversion substrate according to Example 1, since the portion overlapping with the blue filter 1B in plan view was already filled by the second pillar, the wavelength conversion unit 12 could be formed only in two steps, namely, the step of forming the red conversion layer 6R and the step of forming the green conversion layer 6G, and it could be created in a shorter time than before. Also, by setting the heights of the red conversion layer 6R and the green conversion layer 6G lower than that of the reflective partition wall, almost no overlap of these materials on the reflective partition wall could be achieved, and gap control during bonding of the optical module substrate was also easy.

[0047] (Example 2) When forming the first pillar and the second pillar, a color conversion substrate according to Example 2 was manufactured in the same procedure as in Example 1, except that an interference mask with a transmittance of 85% was used for the portion of the second pillar. By the above process, the height of the second pillar became 13 μm, which was lower than that of the first pillar. The color conversion substrate according to Example 2 exhibited the same effects as the color conversion substrate according to Example 1. Furthermore, there was less resistance during the bonding of the optical module substrate, and it could be smoothly joined.

[0048] As described above, each embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and modifications, combinations, etc. of the configuration within the scope not departing from the gist of the present invention are also included.

[0049] · In the above embodiment, an example in which the color filter portion has a blue filter has been described. However, when the light-emitting element of the optical module substrate to be bonded emits blue light and there is no problem in using the blue light as it is as the display light of the display device without adjusting the wavelength, a transparent resin layer may be arranged instead of the blue filter.

[0050] · The transparent resin for forming the first pillar and the second pillar desirably has a light transmittance of 70% or more and 99.5% or less for light with a wavelength of 400 nm or more and 500 nm or less. As the photosensitive resin, acrylic resin, novolak resin, siloxane resin, and epoxy resin can be used.

[0051] · In addition to the phosphor, transparent particles having a refractive index different from that of the base resin, white particles, etc. may be dispersed and arranged in the base resin in the wavelength conversion layer. By doing so, the optical path length of the light incident from the light source can be increased, and the light emission efficiency of the wavelength conversion portion can be improved. As the particles to be dispersed, for example, transparent particles having an average particle diameter of 1 μm or more and 3.0 μm or less can be used. By using particles having a particle diameter larger than the wavelength of visible light with an average particle diameter of 1.0 μm or more and 3.0 μm or less, appropriate light scattering properties can be easily obtained. Transparent fine particles having an average particle diameter of around 0.2 μm or 0.1 μm or less may be used in combination from the viewpoint of a dispersion aid. The particles to be dispersed are preferably optically isotropic. In this specification, "optically isotropic" means that the particles have a crystal structure equal in the a-axis, b-axis, and c-axis, or are amorphous, and the propagation of light is isotropic without being affected by the crystal axis or crystal structure. As an example of the particles to be dispersed, for instance, silica particles have an amorphous structure. In addition, as particles of resins such as resin beads, particles having various properties including refractive index are known, and these particles can be used in combination. Also, particles of resins such as acrylic, styrene, urethane, nylon, melamine, and benzoguanamine may be used in combination.

[0052] · Ultraviolet absorbency may be imparted to the wavelength conversion layer. For example, since zinc oxide particles are transparent in the visible region and can absorb ultraviolet rays of 390 nm or less, these may be mixed into the base resin. Alternatively, an ultraviolet absorber containing a benzophenone-based compound, a benzotriazole-based compound, a triazine-based compound, etc. may be added to the base resin. The ultraviolet absorber preferably has a phenolic hydroxyl group. By providing a phenolic hydroxyl group, crosslinking with a compound having an alkoxymethyl group, a methylol group, etc. during heat treatment becomes possible. By crosslinking, bleed-out of the ultraviolet absorber during long-term storage after curing can be suppressed, and reliability can be improved. The addition amount of the ultraviolet absorber can be, for example, 0.05 mass% or more and 10 mass% or less based on the solid content of the base resin. · Furthermore, the wavelength conversion layer may have a two-layer structure including a layer that exhibits ultraviolet absorbency and a layer for scattering the incident light. In particular, in cases such as when the diameter of the transparent particles to be dispersed is large, there is an advantage that the unevenness due to the transparent particles can be alleviated by the layer containing the ultraviolet absorber.

[0053] · Since the resin materials of the first pillar and the second pillar may turn yellowish with the absorption of short-wavelength light, a small amount of blue pigment may be contained. By containing 0.2 mass% or more and 5 mass% or less of blue pigment with the total solid content including the resin material as the denominator, yellowing over time of the first pillar and the second pillar can be suppressed.

[0054] ·The color filter section and the wavelength conversion section do not necessarily have to be provided over the entire surface of the color conversion substrate. In the color conversion substrate 200A shown in FIG. 8, pixel units Pu each including a set of a red filter 1R, a green filter 1G, and a blue filter 1B partitioned by a reflective partition 5 are arranged in a two-dimensional matrix at a predetermined pitch P1 with an interval It1 in a first direction in which a plurality of color filters are arranged, and at a predetermined pitch P2 with an interval It2 in a second direction orthogonal to the first direction. Neither the reflective partition nor the color filter section is arranged between adjacent pixel units. Even with such an arrangement mode, substantially the same effects as those of the above-described embodiment are achieved. In order to avoid color mixing of light between the second pillars 7b adjacent in the second direction, it is necessary to always arrange a metal thin film between the second pillars 7b and to always provide a predetermined interval. The pixel configuration of the color conversion substrate is not limited to this and can be appropriately determined.

Explanation of Signs

[0055] 1B Blue filter (color filter) 1G Green filter (color filter) 1R Red filter (color filter) 2 Black matrix 5 Reflective partition 6G Green conversion layer 6R Red conversion layer 7a First pillar 7b, 17b, 27b Second pillars 8 Metal thin film 10 Transparent substrate 11 Color filter section 12 Wavelength conversion section 100 Display device 200, 200A Color conversion substrates 201 Adhesive layer 202 LED (light-emitting element)

Claims

1. A transparent substrate, a color filter unit having a grid-like black matrix provided on the transparent substrate and having openings, and a color filter disposed in the openings, a wavelength conversion unit including a reflective partition provided on the color filter unit so as to overlap the black matrix in a plan view, and a wavelength conversion layer provided in an opening of the reflective partition, comprising: the color filter includes at least one of a red filter, a green filter, and a yellow filter, the reflective partition has a first pillar formed in a grid shape with a transparent resin, and a metal thin film provided on the first pillar, formed of the transparent resin and having a second pillar disposed at a position not overlapping with any of the red filter, the green filter, and the yellow filter in a plan view, the first pillar and the second pillar are integrally continuous at least at a lower portion on the color filter unit side, a color conversion substrate.

2. The transmittance of light having a wavelength of 400 nm or more and 500 nm or less in the transparent resin is 70% or more and 99.5% or less, The color conversion substrate according to claim 1.

3. At least one of the wavelength conversion layer and the second pillar is lower than the reflective partition, The color conversion substrate according to claim 1.

4. The reflectance of light having a wavelength of 400 nm or more and 700 nm or less in the metal thin film is 85% or more and 99.5% or less, The color conversion substrate according to claim 1.

5. The height of the reflective partition is 3 μm or more and 40 μm or less, The color conversion substrate according to claim 1.

6. The metal thin film is made of aluminum alone or an alloy of aluminum and neodymium, The color conversion substrate according to claim 1.

7. The metal thin film includes a titanium layer provided on the first pillar, The color conversion substrate according to claim 6.

8. The transparent substrate is made of glass or a synthetic resin, The color conversion substrate according to claim 1.

9. A color conversion substrate according to any one of claims 1 to 8, a light module substrate in which a plurality of light emitting elements that emit blue light are disposed on one surface, and the light emitting elements and the wavelength conversion unit are bonded to the color conversion substrate via an adhesive layer so as to face each other, comprising: a display device.

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