JP7618962B2 - Color filter substrate and display device - Google Patents

Description

The present invention relates to a color filter substrate and a display device equipped with the color filter substrate.

Liquid crystal display devices that use a backlight unit with light-emitting diodes (LEDs) as a light source are widely known. In these liquid crystal display devices, the liquid crystal layer is the display functional layer, and the LEDs of the backlight unit are always lit.

A technology that partially adjusts the luminance of three types of LED chips depending on the position of the display part on the display screen, or uses local dimming to partially stop the light emission, is attracting attention. By using local dimming, the light emission of the display screen can be partially turned off, which greatly improves the display contrast and makes it possible to obtain a contrast comparable to that of an organic EL display.
Micro LEDs have a structure in which LED chips with sizes of approximately 2 μm to 50 μm are arranged in a matrix. By combining micro LEDs with local dimming, it is possible to display images without using liquid crystal.

Display devices using micro LEDs include those that use three types of LED chips that emit red, green, and blue light, and those that use one type of LED chip that emits light in the blue to near-ultraviolet wavelength range. To achieve color display with the latter configuration, a configuration that converts the wavelength of the light emitted from the LED chip, such as a color filter or quantum dots, is essential.

It is expected that display devices will continue to achieve higher resolution, and this will lead to problems such as a decrease in display contrast caused by stray light. In addition, when a display device is used in a bright environment, a decrease in display contrast caused by external incident light will also be a problem.
In organic EL display devices and micro LEDs, circular polarizers are often used to avoid contrast degradation caused by external light entering the display device. Since circular polarizers are expensive, there is a strong demand to omit the circular polarizer.

Patent Document 1 describes a color filter that uses a first light-shielding layer and a second light-shielding layer. The first light-shielding layer is a so-called black matrix, and by sandwiching adjacent portions of different colored layers between the two light-shielding layers, the generation of stray light is suppressed.

Patent No. 6225524

In the configuration of Patent Document 1, since a black matrix is partially provided between the colored layer and the transparent substrate, there is room for improvement in the flatness of the colored layer. As will be described in detail later, there is a concern that this may cause a decrease in contrast.
Furthermore, since no consideration is given to the decrease in contrast caused by external incident light, it is difficult to omit the circular polarizer.

In view of the above circumstances, the present invention aims to provide a color filter substrate that has good visibility, contrast, etc., and can suppress contrast reduction caused by external incident light without requiring a circular polarizing plate.

A first aspect of the present invention is a color filter substrate comprising: a transparent substrate; a semi-transparent film formed on a first surface of the substrate and containing scattering microparticles having a particle size of 1 μm or less ; a color filter section formed on the semi-transparent film and having a plurality of color filters; and a black matrix containing carbon and formed on the color filter section, the black matrix having a lattice pattern including a plurality of openings when viewed in a plane of the substrate.
In the color filter substrate, any one of a plurality of color filters is disposed within an opening in a plan view, and the plurality of color filters have overlapping portions in the plan view.
The black matrix covers the overlapping portion.

A second aspect of the present invention is a display device comprising the color filter substrate according to the first aspect and a light-emitting substrate having a plurality of light-emitting elements.

The present invention provides good visibility, contrast, etc., and can suppress contrast reduction caused by external incident light without the need for a circular polarizer.

1 is a partial cross-sectional view of a color filter substrate according to a first embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional view of the color filter. FIG. 11 is a partially enlarged cross-sectional view of a conventional color filter. 4 is a scanning electron microscope photograph of a structure equivalent to that of FIG. 3. 1 is a graph showing the spectral reflectance characteristics of a color filter. 1 is a graph showing the spectral reflectance characteristics of a color filter provided with a semi-transmissive film. FIG. 11 is a partial cross-sectional view of a modified example of the color filter substrate. FIG. 11 is a partial cross-sectional view of another modified example of the color filter substrate. FIG. 4 is a partial cross-sectional view of a display device according to a second embodiment of the present invention. FIG. 4 is a partial cross-sectional view of another example of the display device. FIG. 4 is a partial cross-sectional view of another example of the display device. FIG. 4 is a partial cross-sectional view of another example of the display device. FIG. 2 is a schematic diagram showing a color filter portion formed substantially flat. 1 is a scanning electron microscope photograph of a color filter portion formed to be substantially flat.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In the following description, the same or substantially the same functions and components are denoted by the same reference numerals, and their description is omitted or simplified, or is described only when necessary. The number of pixels, the number of pixel openings, and the shape of the pixel openings in the present invention are not limited in interpretation by the drawings described below. In addition, in order to easily explain the embodiments of the present invention, the number of components constituting the display device may be reduced in cross-sectional views and plan views to explain the structure of the display device.
In each embodiment, only characteristic features will be described, and descriptions of parts that are no different from components used in a typical display device will be omitted as appropriate.

In this specification, the term "planar view" refers to a state in which an observer views the surface of the transparent substrate on which the semi-transparent film or black matrix layer is not formed, in the normal direction.
In addition, "height" and "thickness" both refer to the dimension in the direction perpendicular to the substrate surface. In other words, "height" and "thickness" have the same meaning for the purpose of describing the present invention.
Ordinal numbers such as "first" and "second" in each configuration are used to avoid confusion of components and do not specify an order or quantity.

Figure 1 is a partial cross-sectional view of a color filter substrate 101 according to this embodiment. As shown in Figure 1, the color filter substrate 101 includes a transparent first substrate 100, a semi-transparent film 1, a color filter portion 2, and a black matrix 6.

The first substrate 100 can be a glass substrate, a quartz substrate, a sapphire substrate, a plastic substrate including a polyimide film, or the like.

The semi-transparent film 1 is formed so as to cover the entire first surface 100 a of the first substrate 100 .
The semi-transparent film 1 is made of a hardened resin, and has carbon particles and optically isotropic transparent fine particles (scattering fine particles) arranged in a dispersed state.

"Optically isotropic" means that the a-axis, b-axis, and c-axis of the transparent fine particles are each equal to each other in a crystal structure, or that the transparent fine particles are amorphous (non-crystalline structure), and the propagation of light is isotropic without being affected by the crystal axis or crystal structure. Silica fine particles are amorphous. As fine particles of resin such as resin beads, fine particles having various properties including refractive index are known, and these resin fine particles can also be used as optically isotropic transparent fine particles. Examples of materials for the resin fine particles include various resins such as acrylic, styrene, urethane, nylon, melamine, and benzoguanamine.
Silicon dioxide (silica) particles are known as a representative inorganic particle that is optically isotropic and transparent in the visible range. The particle diameter of the silica particles can be, for example, within the range of 5 nm to 300 nm. The semi-transparent film 1 may have two or more types of inorganic particles with different particle diameters. Silica particles prevent the generation of secondary particles that tend to occur with carbon alone, and improve the dispersibility of carbon.

With the above configuration, the semi-transparent film 1 has transparency but does not completely transmit light in the visible light region with wavelengths of 400 nm to 700 nm. The light in the visible light region of the semi-transparent film 1 can be, for example, 70% to 99.5%, and preferably 70% to 80%.

The base resin of the semi-transparent film 1 may be any resin that can provide the necessary reliability, such as heat resistance, and may be an alkaline-developable photosensitive resin or a thermosetting resin. Examples of thermosetting resins include epoxy group-containing compounds or resins, and resins having at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups. The base resin is used as a coating liquid in which transparent particles and carbon particles are dispersed using an organic solvent. The semi-transparent film 1 can be formed by applying the coating liquid onto a transparent substrate and curing it with heat or light.

The color filter section 2 is formed on the semi-transparent film 1. In this embodiment, the color filter section 2 has three types of color filters: a red filter R, a green filter G, and a blue filter B. The number and combination of color filters in the color filter section 2 can be set appropriately depending on the application, etc.

The red filter R, green filter G, and blue filter B are formed in strips extending in the same direction (extension direction) in a plan view of the color filter substrate 101. In this embodiment, the color filters are formed in the order of red filter R, green filter G, and blue filter B to form the color filter section 2. For this reason, certain portions of the red filter R on both sides in the width direction perpendicular to the extension direction are covered by the green filter G and blue filter B, respectively. One side of the green filter G in the width direction covers the red filter R, and the other side is covered by the blue filter B. Certain portions of the blue filter B on both sides in the width direction cover the green filter G and blue filter B, respectively.

The red filter R, green filter G, and blue filter B extend in the extension direction while repeating many red, green, and blue unit arrays in the width direction. Furthermore, each color filter has overlapping portions with other color filters on both sides in the width direction, except for the ends of the color filter substrate 101, and these overlapping portions also extend in the extension direction.

Each color filter R, G, and B can be formed using a dispersion in which an organic pigment of the corresponding color is dispersed in a resin. Examples of resin include acrylic.

Examples of red organic pigments that can be used for the red filter R include C.I. Pigment Red 7, 14, 41, 48:2, 48:3, 48:4, 81:1, 81:2, 81:3, 81:4, 146, 168, 177, 178, 179, 184, 185, 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, and 279.
These red pigments may be mixed with yellow pigments or orange pigments. Applicable yellow organic pigments include C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 1 Examples include 17, 118, 119, 120, 123, 126, 127, 128, 129, 147, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 187, 188, 193, 194, 199, 198, 213, and 214.

Examples of green pigments that can be used for the green filter G include C.I. Pigment Green 7, 10, 36, and 37. The above-mentioned yellow pigments may be mixed with these green pigments. In addition, halogenated zinc phthalocyanine green pigments and halogenated aluminum phthalocyanine green pigments can also be suitably used.

Examples of blue pigments that can be used in the blue filter B include C.I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, 64, and the like.
A violet pigment may be mixed with these blue pigments. Examples of the violet pigment include C.I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, and 50.

The above-mentioned pigments are dispersed in a transparent resin together with an organic solvent and a dispersant. The transparent resin is preferably a transparent resin having a visible transmittance of 90% or more, and is preferably an alkali-soluble photosensitive resin containing a resin precursor. The pigment can be contained in the resin in a range of 15% to 65% by mass.
Examples of photosensitive resins include polyimide resins, epoxy resins, acrylic resins, melamine resins, phenolic resins, oxetane resins, siloxane resins, benzoxazine resins, etc., which are obtained by reacting a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group, an amino group, etc. with a (meth)acrylic compound or cinnamic acid having a reactive substituent such as an isocyanate group, an aldehyde group, an epoxy group, a silanol group, etc., to introduce a photocrosslinkable group such as a (meth)acryloyl group or a styryl group into the linear polymer. When the photosensitive resin is cured by irradiation with ultraviolet light having a wavelength of 365 nm or the like, a photopolymerization initiator or the like may be added to the photosensitive resin.

The black matrix 6 is formed on the color filter portion 2 and covers a part of the color filter portion 2. The black matrix 6 has a plurality of first portions extending in the extension direction in a plan view and a plurality of second portions extending in the width direction, forming a lattice pattern having a plurality of openings 40 (see FIG. 1 ) in a plan view of the color filter substrate 101. The first portions and the second portions are formed at equal intervals, but the dimensions of the intervals between the first portions and the second portions are different.
The first portion completely covers an overlapping portion of the color filters (a portion where two types of color filters are present in the thickness direction of the first substrate 100) in a plan view of the color filter substrate 101. The width of the first portion can be appropriately set within a range that completely covers the overlapping portion.

The method for forming the black matrix 6 is not particularly limited, but if an alkali-soluble photosensitive resist in which light-shielding carbon is dispersed is used, a lattice pattern can be easily formed by known photolithography. Carbon is also called carbon black. The optical density (ΔOD) of the black matrix is higher than that of the semi-transparent film 1, and can be, for example, 1 to 4. The optical density of the black matrix 6 may be 4 or more, but since exposure in photolithography becomes difficult, it is preferable to set the optical density to 4 or less when forming the black matrix 6 using photolithography.
The thickness of the black matrix 6 can be set to, for example, about 1 μm.
The film thickness (height) of the black matrix 6 can be appropriately set to, for example, about 2 μm to 50 μm.

The operation of the color filter substrate 101 configured as above during use will be described.
When the color filter substrate 101 is applied to a display device, the second surface 100b opposite to the first surface 100a is disposed facing the user. Therefore, a light source such as a backlight is disposed on the first surface 100a side, and light emitted from the light source is incident on the first surface 100a side.

Figure 2 is a partially enlarged cross-sectional view of the color filter substrate 101. As described above, the black matrix 6 is formed on the overlapping portion 2a of the color filter portion 2. Therefore, light that is obliquely incident on the color filter substrate 101 from a light source or the like first enters the black matrix 6 and is mostly absorbed. This prevents deterioration of contrast and color purity, and maintains high display quality.

When a black matrix 106 is formed between the transparent substrate 100A and the color filter section 2 as in the configuration described in Patent Document 1, the overlapping portion 2a is formed on the black matrix 106 as shown in FIG. 3, and therefore the overlapping portion 2a protrudes significantly above the transparent substrate 100A.
According to the inventors' investigations, when the thickness of each color filter R, G, and B is set to a standard value of 2.2 μm, the thickness of the overlapping areas on the color filter substrate 101 is 2.8 μm at the overlapping area GR between R and G, 2.6 μm at the overlapping area BR between R and B, and 2.7 μm at the overlapping area BG between G and B.
3, when the thickness of the black matrix 106 is 1.2 μm, the thickness of the overlapping portion is 3.9 μm at the overlapping portion GR of R and G, 3.5 μm at the overlapping portion BR of R and B, and 3.7 μm at the overlapping portion BG of G and B. That is, the thickness of the overlapping portion is increased by about 35% to 40%.
Fig. 4 shows a scanning electron microscope (SEM) photograph of the structure shown in Fig. 3. It can be seen that the overlapping portion 2a significantly protrudes in the structure shown in Fig. 3.

When the thickness of the overlapping portion 2a is increased, even if the overlapping portion 2a is covered with another black matrix, the distance between the black matrix and the transparent substrate increases compared to when the overlapping portion 2a is thin, so that the light entering and exiting apertures are different (for example, light entering the green aperture and exiting from the red aperture), and the angle range of light that does not pass through the black matrix increases, resulting in an increase in the amount of light that reduces contrast and color purity.
In the color filter substrate 101 of this embodiment, the thickness of the semi-transparent film 1 formed between the first substrate 100 and the color filter portion 2 is uniform, so that the thickness of the overlapping portion 2a is not excessively large, and an increase in light that causes a decrease in contrast and color purity is suppressed. Furthermore, light that passes through different color filters on the entrance side and the exit side always passes through the semi-transparent film 1 before exiting to the outside, and therefore a part of the light is absorbed by the semi-transparent film 1.
Therefore, in combination with the function of the black matrix 6 described above, the display quality is maintained significantly higher than that of the configuration of Patent Document 1.

In addition to the above-mentioned effects, the semi-transmissive film 1 suppresses the contrast reduction caused by the incident light entering the display device from the outside. The incident light entering the display device from the outside passes through the semi-transmissive film 1 first, and is attenuated according to the transmittance of the semi-transmissive film 1. When the attenuated light is reflected inside the display device and exits the display device, it passes through the semi-transmissive film 1 again and is attenuated. That is, the incident light entering the display device from the outside is attenuated to a ratio of the value obtained by squaring the transmittance of the semi-transmissive film 1 before it exits the display device and is visually recognized by the user. For example, if the transmittance of the semi-transmissive film 1 in the visible light region is 75%, the incident light entering the display device from the outside is attenuated to at least 56.25% of the light at the time of entry and exits the display device.
As a result, in a display device to which the color filter substrate 101 is applied, a decrease in contrast caused by external incident light entering the display device is suitably suppressed, and therefore a circular polarizing plate is not required.

In the color filter substrate 101 of this embodiment, there is no black matrix between the first substrate 100 and the color filter section 2. Therefore, when the black matrix is viewed from the second surface 100b side, ripples (variations in reflectance) occur due to the reflection and interference of light at the interface between the color filter section 2 and the black matrix 6, and the black matrix 6 may be observed to be slightly colored. Such coloring caused by reflected light is easily observed when the display device is turned off and black is displayed. In addition, in such a case, it may appear rainbow-colored when viewed from an oblique direction by a user, which may reduce visibility.
In the color filter substrate 101 of this embodiment, the semi-transparent film 1 provided between the first substrate 100 and the color filter portion 2 suppresses such a phenomenon.

5 is a graph showing the spectral reflectance characteristics of a color filter without a semi-transmissive film 1. The reflectance is based on the reflectance of an aluminum film (100%).
In FIG. 5, a high reflectance of 1.0% or more is observed in the red and green filters, and the ripple in the red filter is large at about 1.5 points (% points).
The ripple is the difference between the peak and valley of the reflectance spectral curve within 50 nm units of the reflectance measured in the visible range of light wavelengths from 400 nm to 700 nm, but it can also be simply evaluated using the reflectance peak value within 50 nm units. In the simplified evaluation, the apparent reflectance fluctuation value is a large value.

Figure 6 is a graph showing the spectral reflectance characteristics of a color filter provided with a semi-transparent film 1 when light is applied from the semi-transparent film 1 side. In the visible light range from 400 nm to 700 nm, the reflectance of all filters is well below 1.0%, and the ripple of the red filter is suppressed to 0.31 points. The semi-transparent film 1 in Figure 6 contains 4% by weight (wt%) of carbon black and silica particles, and has a reflectance of 70%.

In high-resolution pixels such as 400 ppi (pixels per inch) and 800 ppi, visibility is likely to decrease if the reflectance of the color filter or black matrix exceeds 1%. In particular, as the resolution increases, the area ratio of the black matrix, which has a high reflectance, increases, so it is important to reduce the reflectance of the color filter, including the black matrix. It can be said that the color filter substrate according to this embodiment has a desirable low reflectance.

In the case of a semi-transparent film containing an organic pigment as the main pigment component, the reflected light from the interface with the black matrix layer may appear yellowish. The semi-transparent film 1 of this embodiment contains carbon as the main pigment component and does not contain any organic pigment, so the reflected light is flat and does not exhibit such coloring of the reflected light. "Flat reflected light" means that in the visible range of light wavelengths from 400 nm to 700 nm, there is no unevenness (fluctuation) of two or more points in the transmittance in a small range, such as 50 nm, and a transmittance curve that is close to a straight line is obtained. The flat reflected light of the semi-transparent film 1 contributes to the ripple suppression effect described above.

The scattering particles contained in the semi-transparent film 1 have a particle size on the submicron order, so they do not scatter visible light, or if they do, they do so very little. When the scattering particles are made of silicon dioxide, the refractive index of silicon dioxide (e.g., 1.46 to 1.47) is small, so they have the effect of lowering the refractive index of the semi-transparent film 1. As a result, light reflection at the interface between the semi-transparent film 1 and the color filter is suppressed, and visibility can be improved.

The color filter substrate of this embodiment may include a transparent layer 21 made of resin or the like between the color filter section 2 and the black matrix 6, as in the modified color filter substrate 102 shown in FIG. 7. By positioning the color filter section 2 within the transparent layer 21, the black matrix 6 can be formed on the flat transparent layer 21. As a result, it becomes easier to control the dimensions of the black matrix 6 and its position on the color filter substrate.

The color filter substrate of this embodiment may include a transparent filling layer 22 that fills the openings 40 of the black matrix 6, as in a modified color filter substrate 103 shown in Fig. 8. Although an example in which the transparent layer 21 is provided is shown in Fig. 8, the transparent layer 21 may be omitted. Although an example in which the filling layer 22 is thicker than the black matrix 6 is shown in Fig. 8, the filling layer 22 may be the same thickness as the black matrix 6, or may be thinner than the black matrix 6.
By providing the filling layer 22, damage or deformation of the black matrix 6 can be prevented, and this is particularly suitable when the black matrix 6 is tall. Furthermore, by incorporating various materials into the filling layer 22, various properties can be imparted to the color filter substrate 103. This point will be described in detail in the second embodiment.

A second embodiment of the present invention will be described with reference to Figures 9 to 12. In this embodiment, a display device including the color filter substrate according to the first embodiment will be described.
In the following description, components common to those already described will be given the same reference numerals and duplicated description will be omitted.

Figure 9 is a schematic cross-sectional view of a display device 120 equipped with a color filter substrate 102. The display device 120 is equipped with a color filter substrate 102 and a light-emitting substrate 200 having light-emitting elements 32. The light-emitting substrate 200 is disposed so that the surface on which the light-emitting elements 32 are arranged faces the color filter substrate 102.

As the light-emitting element 32, a light-emitting diode also called an LED (Light Emitting Diode), an organic EL (Organic Electroluminescence) also called an OLED (Organic Light Emitting Diode), etc. can be used.

Compounds such as aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), indium gallium nitride (InGaN)/gallium nitride (GaN)/aluminum gallium nitride (AlGaN), gallium phosphide (GaP), zinc selenide (ZnSe), and aluminum indium gallium phosphide (AlGaInP) are used for LEDs. Gallium nitride (GaN) is mainly used for blue light-emitting diodes, which will be described later as monochromatic light-emitting LEDs. The blue light-emitting diodes here may also emit light in the near ultraviolet region, such as 365 nm, 385 nm, and 395 nm.
For example, a mini LED may use an LED chip with a size of 40 μm to 200 μm. For example, a micro LED may use an LED chip with a size of 2 μm to 60 μm. The LED chip may be a horizontal LED with the n-side electrode and the p-side electrode on the same side, or a vertical LED with the n-side electrode and the p-side electrode on different sides (opposite parallel surfaces) in the thickness direction of the LED.

At least one light emitting element 32 is arranged in each opening 40 in a plan view of the display device 120. The light emitting element 32 is driven by a transistor or the like provided on the light emitting substrate 200. The material of the light emitting substrate 200 may be the same as or different from the material of the first substrate 100, but when the light emitting substrate 200 is bonded to the color filter substrate 102, it is preferable that the materials are the same. Furthermore, it is preferable that the material of the light emitting substrate 200 and the material of the first substrate 100 have the same thermal expansion coefficient. If the thermal expansion coefficients differ greatly, warping or peeling may occur when the temperature of the display device increases.

The display device 120 functions as a display device capable of displaying color by independently driving the multiple light-emitting elements 32 on and off. In the display device, a set of an opening 40 in which a red filter R is arranged, an opening 40 in which a green filter G is arranged, and an opening 40 in which a blue filter B is arranged functions as a pixel.

In the display device 120, as described above, the color filter substrate 102 effectively suppresses the decrease in color purity and contrast caused by a portion of the light emitted from the light emitting element 32 entering an opening other than the opening 40 in which the light emitting element 32 is disposed. As described above, in the color filter substrate 102, the transparent layer 21 makes it easy to adjust the position of the black matrix 6, and therefore, by optimizing the height and position of the black matrix 6, it is easy to reduce the adverse effects of stray light.
Instead of the color filter substrate 102, the color filter substrate 101 or the color filter substrate 103 may be used.

A display device 122 shown in FIG. 10 includes a color filter substrate 103A and a light emitting substrate 200A.
The basic structure of the color filter substrate 103A is similar to that of the color filter substrate 103, but differs in that scattering particles 28 are disposed in the filling layer 22. As the scattering particles 28, various transparent particles having a particle size on the order of microns, which are used in known scattering films that are often applied to display devices, can be used. It is preferable that the particle size of the scattering particles is within the range of 1 μm to 10 μm, since this provides good scattering efficiency.
The basic configuration of the light emitting substrate 200A is similar to that of the light emitting substrate 200, but differs in that it has light reflective partitions 41. The light reflective partitions 41 are formed in a lattice pattern similar to that of the black matrix 6 in a plan view of the display device 122, and surround the periphery of each light emitting element 32.

In the display device 122, most of the light emitted from the light emitting element 32 that does not travel toward the opening 40 is reflected by the light reflective partition 41 and introduced into the opening 40. The light that has entered the opening 40 is scattered by the scattering particles 28 of the filling layer 22 and travels to the color filter section 2.
In the display device 122, the light utilization efficiency of the light emitting elements 32 is improved, and high display quality is realized due to the above-mentioned function of the color filter substrate 103A.

A display device 123 shown in FIG. 11 includes a color filter substrate 103B and a light emitting substrate 200A.
In the filling layer 22 of the color filter substrate 103B, a wavelength conversion material corresponding to the color filter arranged in the opening 40 is arranged. That is, a red phosphor 25 is arranged as a wavelength conversion material in the filling layer 22 of the opening 40 in which the red filter R is arranged, a green phosphor 26 is arranged as a wavelength conversion material in the filling layer 22 of the opening 40 in which the green filter G is arranged, and a blue phosphor 27 is arranged as a wavelength conversion material in the filling layer 22 of the opening 40 in which the blue filter B is arranged.

As the red phosphor 25, Y ₂ O ₂ S: Eu ³⁺ , YAlO ₃ : Eu ³⁺ , Ca ₂ Y ₂ (SiO ₄ ) ₆ : Eu ³⁺ , LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu ³⁺ , YVO ₄ : Eu ³⁺ , CaS:Eu ³⁺ , _Gd2O3 :Eu3 ⁺ , _Gd2O2S :Eu3 ⁺ , Y(P,V) _O4 : ^Eu3+ _{, Mg4GeO5.5F :} Mn4 ⁺ , _{Mg4GeO6 :} Mn4 ⁺ _, K ₅ Eu _2.5 (WO ₄ ) _6.25 , _{Na5Eu 2.5} ( _WO4 ) _6.25 , _K5Eu2.5 ( _MoO4 ) _{6.25 , Na5Eu2.5} (MoO4 _{) 6.25 , K2MF6 (} M is Si, Ge, Ti) Examples of the above include Mn4 ⁺ .
_As the green phosphor 26, ₍ BaMg) _Al10O17 :Eu2 ⁺ , Mn2 ⁺ _, Sr4Al14O25 _: Eu2 ⁺ , ( _SrBa ) _{Al12Si2O8 :} Eu2 ⁺ , ₍ BaMg) _2SiO4 : Eu ²⁺ , Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ , Sr ₂ P ₂ O ₇ -Sr ₂ B ₂ O ₅ : Eu ³⁺ , (BaCaMg) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , Sr ₂ Si ₃ O ₈ -2SrCl ₂ :Eu2 ⁺ , Zr ₂ SiO ₄ , MgAl ₁₁ O ₁₉ : Ce ³⁺ , Ba ₂ SiO ₄ : Eu ²⁺ , Sr ₂ SiO ₄ : Eu ²⁺ , (BaSr)SiO ₄ : Eu ²⁺ , Si ₆ AlON ₈ : Eu, nitrides with β-type Si ₃ N ₄ crystal structure Alternatively, oxides and the like can be exemplified.
_As the _blue phosphor 27, _{Sr2P2O7 :} Sn4 ⁺ , Sr4Al14O25:Eu2 ⁺ _, BaMgAl10O17: ^Eu2 ₊ , _{SrGa2S4 :} Ce3 ⁺ _{, CaGa2S4} ^: _{Ce3 +} , (Ba, Sr) (Mg, Mn) Al ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ca, Ba 2, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , BaAl2SiO8: Eu ²⁺ , Sr2P2O7: Eu ²⁺ , _Sr5 ( _PO4 ) _3Cl :Eu2 ⁺ , (Sr,Ca,Ba) ₅ ( _PO4 )3Cl _: Eu2 ⁺ , _{BaMg2Al16O27 :} Eu2+ _{, ( Ba} ,Ca) ⁵ ( _PO4 ) _3Cl :Eu2 ₊ , ^Ba3MgSi2O ₈ : Eu ²⁺ , Sr ₃ Examples include MgSi ₂ O ₈ :Eu ²⁺ .
It is preferable that the particle size of each of the phosphors 25, 26, and 27 is within the range of 1 μm to 10 μm, since this provides good wavelength conversion efficiency.

In the display device 123, the filling layer 22 in which the phosphor is arranged functions as a wavelength conversion layer that converts the wavelength of the light emitted from the light emitting element 32. Therefore, the light emitted from the light emitting element 32 passes through the filling layer 22 and becomes light of a color close to that of the color filter arranged in the opening 40 before entering the color filter section 2. This allows the display device 123 to perform color display with high color purity.

Because a certain optical path length is required for wavelength conversion in the filling layer 22, it is preferable to set the height of the black matrix 6 in the display device 123 taking this into consideration. Specifically, it is preferable for the height to be between 2 and 5 times the particle size of the phosphor. Therefore, when the particle size of each phosphor is within the above-mentioned range, the height of the black matrix 6 can be set in the range of 2 μm to 50 μm depending on the particle size of the phosphor.

In the display device 123, quantum dots may be used as the wavelength conversion material.
Furthermore, the light emitting element corresponding to the opening in which the blue filter B is disposed may be a blue LED. In this case, scattering particles 28 may be disposed in the filling layer 22 instead of the blue phosphor 27, or the filling layer 22 may be made of only resin without disposing any particles.

A display device 124 shown in FIG. 12 includes a color filter substrate 103, a liquid crystal substrate 300, and a light emitting substrate 200B.
The basic configuration of the light-emitting substrate 200B is similar to that of the light-emitting substrate 200A, but differs in that the lattice pattern of the light-reflective partitions 41 is divided into pixels, and three types of light-emitting elements, i.e., a red LED 32A, a green LED 32B, and a blue LED 32c, are arranged in each pixel.
The liquid crystal substrate 300 has a known configuration including a liquid crystal layer 301 and an array substrate for driving the liquid crystal layer. The liquid crystal substrate 300 is disposed between the color filter substrate 103 and the light emitting substrate 200B, and functions as a display function layer. In the liquid crystal substrate 300, the horizontally aligned liquid crystal may be driven by a FFS (fringe field switching) method.

In the display device 124 having the above-mentioned configuration, the displayed shape, pattern, etc. are controlled entirely by the liquid crystal substrate 300, and the light emitting substrate 200B basically functions as a direct type backlight.
The display device 124 may include other components, such as a polarizing plate, a retardation plate, a prism sheet, a cover glass, a touch panel, and an alignment film, as necessary.

The display devices shown in the present embodiment can be applied to various fields, such as mobile phones, portable game devices, portable information terminals, personal computers, electronic books, video cameras, digital still cameras, head-mounted displays, navigation systems, audio playback devices (car audio, digital audio players, etc.), copiers, facsimiles, printers, multifunction printers, vending machines, automated teller machines (ATMs), personal authentication devices, optical communication devices, and IC cards.
These electronic devices may be equipped with antennas to enable communication and contactless power supply and reception.

Although each embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and configuration changes and combinations that do not deviate from the gist of the present invention are also included.

For example, the semi-transparent film in the present invention may not be provided in some openings. For example, since the ripple of a blue filter is smaller than that of other color filters, it is possible to not provide a semi-transparent film only in the opening where the blue filter is placed. Alternatively, a semi-transparent film may be provided only in the opening where a red filter, which has a large ripple, is placed. Such shape changes in the semi-transparent film can be easily performed by patterning using photolithography.

In the semi-transparent film, instead of silica, fine particles made of inorganic oxides such as titanium oxide, zinc oxide, calcium carbonate, etc. may be contained as scattering fine particles. These fine particles may be used in combination with silica.

In the color filter substrate of the present invention, as described above, the overlapping portions of the color filter portions are unlikely to become thick, so by thinning the color filters, a color filter portion 2 in which the overlapping portions 2a hardly protrude can be formed as shown in FIG. 13. This makes it suitable for use in high-definition pixels (e.g., pixel pitch of 15 μm or less). FIG. 14 shows an SEM photograph of the color filter portion formed as shown in FIG. 13. In this example, the film thicknesses of the red filter R and green filter G were each 1.5 μm. The amount of protrusion of the overlapping portions 2a was approximately 0 to -0.4 μm. In other words, the overlapping portions 2a were either the same thickness as the other portions or slightly recessed, forming a color filter portion that was almost flat overall.

1 Semi-transparent film 2 Color filter portion 6 Black matrix 21 Transparent layer 22 Filling layer 25 Red phosphor (wavelength conversion material)
26 Green phosphor (wavelength conversion material)
27 Blue phosphor (wavelength conversion material)
28 Scattering particles 32 Light emitting element 100 First substrate (substrate)
101, 102, 103, 103A, 103B Color filter substrate 120, 122, 123, 124 Display device 200, 200A, 200B Light emitting substrate 300 Liquid crystal substrate B Blue filter (color filter)
G Green filter (color filter)
R Red filter (color filter)

Claims (12)

A transparent substrate;
a semi-transparent film formed on a first surface of the substrate , the semi-transparent film containing scattering particles having a particle size of 1 μm or less ;
a color filter section formed on the semi-transmissive film and having a plurality of color filters;
a black matrix containing carbon and formed on the color filter portion, the black matrix having a lattice pattern including a plurality of openings when viewed from above the substrate;
Equipped with
any one of the plurality of color filters is disposed within the opening in the plan view;
the plurality of color filters have overlapping portions in the plan view,
The black matrix covers the overlapping portion.
Color filter substrate. The semi-transparent film contains carbon and has a light transmittance of 70% or more and 99.5% or less in the wavelength range of 400 nm to 700 nm.
The color filter substrate according to claim 1 . The scattering fine particles are made of silica.
The color filter substrate according to claim 1 . the reflectance of the color filter portion for light in a wavelength range of 400 nm to 700 nm applied from a second surface opposite to the first surface is less than 1%, and the magnitude of the reflectance fluctuation is less than 1 percentage point ;
The color filter substrate according to claim 1 . The semi-transparent film is disposed in all of the plurality of openings.
The color filter substrate according to claim 1 . Further comprising a transparent layer provided between the color filter portion and the black matrix.
The color filter substrate according to claim 1 . further comprising a filler layer disposed within the plurality of openings.
The color filter substrate according to claim 1 . The filling layer contains scattering particles that scatter visible light.
The color filter substrate according to claim 7 . The filling layer contains a wavelength converting material.
The color filter substrate according to claim 7 . the wavelength converting material is in particulate form,
The height of the black matrix is between 2 and 5 times the particle size of the wavelength converting material.
The color filter substrate according to claim 9 . A color filter substrate according to claim 1 ,
A light emitting substrate having a plurality of light emitting elements;
Equipped with
Display device. a liquid crystal substrate having a liquid crystal layer and disposed between the color filter substrate and the light emitting substrate;
The display device according to claim 11 .

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