JP7439530B2 - Optical module and display device - Google Patents

Description

The present invention relates to an optical module using an LED as a light emitting element and a display device equipped with the same.

Organic electroluminescent display devices (hereinafter referred to as organic EL) are known as display devices, but they suffer from problems such as low luminous efficiency of the organic EL layer, changes in luminescence over time, and short lifetime. There's a problem. Recently, display devices using LEDs made of inorganic materials (LED displays) are expected to be used as display devices that contribute to making mobile devices thinner. LEDs are attracting more attention because they have higher luminous efficiency than organic EL, and the luminance can be easily adjusted with the amount of current (brighter display is possible). Organic EL is prone to burn-in when the amount of current is increased, which affects the life of the element.

A liquid crystal display device is a display device that uses a backlight using an LED (Light Emitting Diode) as a light source, and uses liquid crystal as a display function layer that switches between transmitting and non-transmitting light in a pattern.

2. Description of the Related Art In recent years, a technology that uses a direct type backlight called a mini-LED, which has a configuration in which a plurality of LED chips having a size of about 5 μm to 200 μm are arranged in a matrix, in a liquid crystal display device has been attracting attention. There are two types of mini-LEDs: one uses three types of LED chips that emit red light, green light, and blue light to produce full-color light, and the other uses a blue-emitting LED chip as a light source and converts the wavelength of blue light to produce full color light.

Further, a technique that partially adjusts the luminance of the three types of LED chips depending on the position of the display area on the display screen or uses local dimming to partially stop the light emission is attracting attention.

In a liquid crystal display device using such local dimming, it is possible to partially turn off light emission on the display screen, so that the contrast of the display can be greatly improved. In conventional liquid crystal display devices, since the backlight is always on, slight light leakage occurs when the liquid crystal displays black, making it difficult to obtain contrast comparable to that of organic EL.

A micro LED is a display device that has a structure in which LED chips with a size of about 2 μm to 50 μm are arranged in a matrix, and displays by individually driving each of the plurality of LED chips. Such micro LEDs can display patterns without using liquid crystal.

There are two types of micro LEDs: one uses three types of LED chips that emit red light, green light, and blue light, similar to the mini LED mentioned above, and the other uses only monochromatic LED chips such as LED chips that emit light in the blue wavelength range. It is broadly divided into. In micro-LEDs, individual LED chips play the role of a display functional layer.

However, whether it is a micro LED or a mini LED, there is a concern that the light emitted from each LED chip may enter adjacent pixels as stray light, resulting in a decrease in display contrast and color purity.

Patent Document 1 discloses a technology of a partition wall surrounding a phosphor layer and a light source (light emitting diode or organic electroluminescence) as a countermeasure against color bleeding and stray light. For example, it is disclosed in claim 2 that the partition wall is a partition wall having light-scattering or light-reflecting properties. Further, claim 3 discloses a partition wall having a laminated structure of a light-scattering layer and a light-absorbing layer.

However, there is no disclosure at all about the difficulty of forming light-scattering partition walls using well-known photolithography techniques including exposure and development steps. Photolithography technology, which includes exposure and development steps, is a typical technology for forming low-cost resin patterns and the like without using expensive equipment. In this case, when forming light-scattering particles on the photosensitive resist using, for example, materials in the [0074] paragraph and further [0080] paragraph, the light used for exposure is scattered in the photosensitive resist during exposure. It is extremely difficult to obtain a pattern shape that does. Specifically, it is difficult to form it in the "shape that gradually becomes larger toward the substrate" as shown in FIG. 1 or as claimed in claim 1. It is difficult to obtain the desired barrier rib shape because light scattering is large near the opening of the photomask used for exposure, and light scattering is large within the resist.

Patent Document 2 discloses a partition wall containing carbon black or the like in the [0015] paragraph, and further discloses a light shielding portion having a light shielding function in the [0017] paragraph. The thickness of the partition wall portion is thicker than the thickness of the colored portion (color filter).

The technology of Patent Document 2 requires thick partition walls with high light absorption, and contrary to Patent Document 1, it is difficult for exposure light to reach the deep part of the partition walls, causing problems such as peeling off of the partition walls and deformation of the partition walls during the manufacturing process. Become. In recent years, there has been a remarkable progress toward higher definition in display devices, and there is a demand for thin partition walls with a high aspect ratio.

Japanese Patent Application Publication No. 2015-64391 JP2018-189920A

The present invention improves the partition walls formed in displays such as micro LEDs and mini LEDs for the purpose of suppressing stray light that enters pixels adjacent to pixels where light emitted from light emitting elements (LEDs) should originally enter, and improves the display contrast. The present invention aims to contribute to improving color purity and color purity, and to propose a configuration suitable for manufacturing fine-shaped (high aspect) partition walls by photolithography.

The optical module according to the first aspect of the present invention is
An optical module having, on one side of a substrate, a light emitting region in which a plurality of light emitting elements are arranged, and a partition wall partitioning into units (blocks) each including one or more of the light emitting elements,
The light emitting elements are all blue light emitting LEDs having a light emission peak at the same wavelength in the blue region,
The partition wall is characterized in that it contains a red pigment and a yellow pigment so as to absorb the light emitted by the blue light emitting LED in the blue region including the light emission peak, and to transmit light having a wavelength of 365 nm.

By providing a wavelength conversion functional layer having a light scattering function on the light emitting region, the optical module can be applied as a white backlight.

An optical module characterized in that it is applied to full-color display by having a color filter on the wavelength conversion functional layer of the optical module.

A display device including an optical module configured to include a wavelength conversion function layer and a color filter, which can be applied as an LED display panel by having a circuit section for controlling the light emitting element to emit light and stop emitting light for each block. Ru.

A display device including an optical module configured to include a wavelength conversion function layer and a color filter, and an array substrate including a transparent substrate, a liquid crystal layer, and a thin film transistor array for driving the liquid crystal layer, at a position facing the color filter. By doing so, it can be applied as an LCD display panel using an optical module as a backlight.

The present invention provides a configuration that reliably suppresses stray light and is suitable for manufacturing fine-shaped (high aspect ratio) partition walls by photolithography, and improves display contrast and color purity of optical modules (and display devices) to which it is applied. This makes it possible to contribute to the improvement of

FIG. 2 is a cross-sectional view showing an example of the basic configuration of an optical module. FIG. 2 is a plan view and a partially enlarged view showing an example of the basic configuration of an optical module. FIG. 2 is a plan view and a partially enlarged view showing an example of the basic configuration of an optical module. FIG. 2 is an explanatory diagram showing a state in which the light emitting elements mounted on the optical module of FIG. 1 are electrically connected. An enlarged view of section C in FIG. 4. FIG. 1 is a cross-sectional view showing a display device to which an optical module is applied. 7 is a partial plan view and a circuit diagram of the display device of FIG. 6. FIG. FIG. 1 is a cross-sectional view showing an example of a display device according to the present invention. FIG. 3 is a cross-sectional view showing another example of the display device according to the present invention. A partial cross-sectional view of a vertical LED chip. A partial cross-sectional view of a horizontal LED chip. A graph showing the spectral characteristics of a red pigment (PR254), a yellow pigment (PY138), and a black pigment.

Embodiments of the present invention will be described below with reference to the drawings.

In the following description, the same or substantially the same functions and components are given the same reference numerals, and the description thereof will be omitted or simplified, or will be described only when necessary. In each figure, in order to make each component large enough to be recognized on the drawing, the dimensions and proportions of each component are appropriately different from those in reality. In addition, if necessary, elements that are difficult to illustrate, such as the structure of a thin film transistor including a semiconductor channel layer, the structure of multiple layers forming a conductive layer, wiring connections to circuit parts, switching elements (transistors), etc. , and some illustrations are omitted.

In each of the embodiments described below, characteristic parts will be explained, and for example, the differences between the components used in a normal display device and the components used in the display device according to this embodiment will be explained. Descriptions of parts that are not included will be omitted.

Ordinal numbers such as "first" and "second" such as the first substrate, the second substrate, the first transparent resin layer, the second transparent resin layer, and the third transparent resin layer are used to avoid confusion between the constituent elements. The quantity is not limited. Further, the matrix arrangement of light emitting elements refers to an arrangement in which blocks including one or more light emitting elements are arranged in a matrix at a constant pitch when viewed from above. Each block unit surrounded by partition walls includes one or more light emitting elements, which are light emitting diodes.

[First embodiment: Basic configuration of optical module]
Hereinafter, an optical module related to the present invention will be explained with reference to the drawings.
FIG. 1 is a sectional view showing an example of the basic configuration of an optical module 1 according to the present invention, in which a light emitting element (LED) 3 and a partition wall 2 are arranged on one surface 101 of a substrate 100. In the figure, three light emitting elements 3 are included in each of the three partitions in a cross-sectional view within the arrangement interval 4 of the partition walls 2 that partition the light emitting region formed by the arrangement of the light emitting elements 3 in units of blocks. (The number of light emitting elements when arranged in the depth direction is not considered)
FIG. 2 is a plan view and a partially enlarged view of FIG. 1. FIG. 1 corresponds to a cross-sectional view taken along line a-a in the figure, viewed from the direction of arrow b. In FIG. 2, the light emitting region is divided into blocks in a grid pattern by partition walls 2, and six light emitting elements 3 are arranged in a matrix in each block.

The light emitting area may be divided into stripes as shown in FIG. 3 . In FIG. 3, the light emitting elements 3 are arranged in a line in a linear area that is not a closed space and is sandwiched between adjacent partition walls 2 (open ends). In this application, the form shown in FIG. 3 is also defined as a "block". The shape of the blocks partitioned by the partition walls 2 is not limited to those shown in FIGS. 2 and 3, and the arrangement of the light emitting elements 3 arranged within the blocks can also be arbitrarily selected.

The optical module according to the present invention enables light emission control on a pixel-by-pixel basis that defines a display pattern by individually driving light-emitting elements in blocks partitioned by partition walls, and is capable of controlling light emission on a pixel-by-pixel basis that defines a display pattern. Application in the form is also possible. Alternatively, the optical module can be applied to a display section that defines a display pattern separate from the optical module, such as a liquid crystal panel, to provide a display device to which a local dimming method is applied.

As will be described later, the light emitted from the light emitting element, which mainly uses blue light emitting LEDs, is monochromatic light. Therefore, when performing color display by coloring the display pattern pixel by pixel, the emitted light wavelength must be converted (or The optical module can be applied to color displays (LED, LCD) by using a wavelength conversion layer (for white light) and a color filter if necessary.

It is desirable that the height H1 of the partition wall 2 is higher than the height (thickness) of the light emitting element 3. Although it depends on the thickness of the light emitting element 3, the height H1 of the partition wall can be, for example, from 2 μm to 50 μm, or more than 50 μm.

Substrates that can be used for the substrate 100 include glass substrates, ceramic substrates, quartz substrates, sapphire substrates, silicon substrates, and plastic substrates. For example, a structure may be applied in which a buffer layer having a lattice constant close to that of GaN (gallium nitride), which is a compound semiconductor, is laminated on a sapphire substrate or a silicon substrate, and GaN is epitaxially grown to form a light emitting element. Various materials such as AlN (aluminum nitride) and TiN (titanium nitride) can be used as the buffer layer. Hereinafter, a light emitting element or a light emitting diode may be simply referred to as an LED, a blue light emitting LED, a horizontal LED, a vertical LED, or the like.

As the light emitting element 3, an element that emits blue light is used. The semiconductor light emitting device may be appropriately selected from nitride-based semiconductors such as InAlGaN, semiconductors such as GaAlAs, AlInGaP, GaAsP, and GaP, and semiconductor light-emitting elements made of materials other than these. The design of the emission wavelength can be changed depending on the material of the semiconductor layer in the semiconductor stacked structure and its mixed crystal ratio. The composition, emission wavelength peak, size, number, etc. of the light emitting elements used may be appropriately selected depending on the purpose.

As the light emitting element, a so-called vertical type LED shown in FIG. 10 and a so-called horizontal type LED shown in FIG. 11 can be used. Although vertical LEDs are shown in FIG. 1, horizontal LEDs may also be used. In the case of a horizontal LED, the mounting method may differ depending on whether it is face-up (p-side electrode and n-side electrode are on the top) or face-down (p-side electrode and n-side electrode are on the bottom). In the case of face-up, wire bonding technology using gold wire can be applied. In the case of a face-down configuration and a lower electrode, mounting using an anisotropic conductive film or a low melting point metal such as an In alloy can be applied. In FIG. 1, since the mounting method differs depending on the structure of the light emitting element to be applied, a vertical LED is typically shown, and the configuration related to mounting is omitted from the illustration.

In the display device shown in FIG. 1 in which the display functional layer is a liquid crystal layer, several tens to hundreds of light emitting elements 3 are arranged in a block defined by the arrangement interval 4 of the partition walls 2, and each block emit light. A controlled local dimming method can be adopted.

Hereinafter, the selection of "a pigment that has the property of absorbing the emission wavelength range of a light emitting element and transmitting light with a wavelength of 365 nm", which is the main feature of the present invention, and the technical significance thereof will be explained.

The emission wavelength of blue-emitting LEDs is approximately within the range of 440 nm to 500 nm, and the emission peak wavelength is within the range of 460 nm to 480 nm. Therefore, in order to suppress the adverse effects of stray light on adjacent pixels, the range in which the partition wall has high light absorption may be set within the range of 440 nm to 500 nm, which corresponds to the emission wavelength range of the blue light emitting LED.

The spectral characteristics Y of the yellow pigment C.I. Pigment Yellow 138 (hereinafter referred to as PY138) and the spectral characteristics R of the red pigment C.I. Pigment Red 254 (hereinafter referred to as PR254) are shown in FIG. The spectral characteristics BM of the carbon pigment used in the black matrix of the color filter are also shown. Spectral characteristic BM made of black pigment has almost zero transmittance at wavelengths in the visible range. (→The absorbance is large)
The relationship between absorbance A (unitless ratio) and transmittance T [%] is shown in Table 1: A=-log ₁₀ (T/100)=2-log ₁₀ T
The relationship holds true.

The yellow pigment PY138 exhibits desirable spectral characteristics, with a transmittance of 0 (→absorbance is large) below 500 nm in terms of absorption of the emission wavelength of a blue-emitting LED. However, since it has almost no transparency at the i-line exposure wavelength of 365 nm used for exposure in photolithography, when patterning a photoresist containing PY138, it is difficult to expose and develop a thick photoresist. When manufacturing barrier ribs that are tall and have a high aspect ratio, exposure (reaction) occurs throughout the entire thickness of the photoresist, resulting in a disadvantage of insufficient sensitivity.

Similarly, even when patterning a photoresist containing a carbon pigment having the spectral characteristic BM, it is difficult to manufacture partition walls that are tall and have a high aspect ratio.

The spectral characteristic R of the red pigment PR254 shows that the transmittance at wavelengths from 440 nm to 500 nm is as low as 10% or less, and it appears to have light absorption properties, while transmitting 40% or more of light with a wavelength of 365 nm (i-line). It has characteristics. Therefore, when patterning a photoresist containing PR254, it is expected to be suitable for manufacturing barrier ribs that are tall and have a high aspect ratio.

Therefore, a photoresist that combines the spectral characteristics of both the yellow pigment PY138 and the red pigment PR254 has both advantages in manufacturing barrier ribs and the property that the manufactured barrier ribs suitably absorb the emission wavelength of blue-emitting LEDs. It will be combined.

Note that the level of light emission absorption of the blue-emitting LED and the light transmission level of the exposure wavelength can be adjusted by adjusting the mixing ratio of the red pigment and the yellow pigment.

In addition to the above-mentioned red pigments, red pigments applicable to the present invention include, for example, C.I. 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, Red pigments such as 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, 279, etc. can be used, and yellow pigments and orange pigments can also be used in combination.

As a yellow pigment, C. I. Pigment Yellow1, 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, 117, 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 , 214, etc.

These red pigments and yellow pigments are used after being dispersed in a transparent resin together with an organic solvent and a dispersant. The transparent resin is desirably a transparent resin having a transmittance in the visible range of 90% or more, and desirably an alkali-soluble photosensitive resin containing a resin precursor. The pigment can be contained in a range of 15% by mass to 45% by mass based on the resin.

Examples of photosensitive resins include (meth)acrylic compounds and cinnamon, which have reactive substituents such as isocyanate groups, aldehyde groups, and epoxy groups on linear polymers that have reactive substituents such as hydroxyl groups, carboxyl groups, and amino groups. A resin in which a photocrosslinkable group such as a (meth)acryloyl group or a styryl group is introduced into the linear polymer by reacting with an acid is used.

Monomers and oligomers that are precursors of transparent resins include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, polyethylene glycol di(meth)acrylate, and pentaerythritol tri(meth)acrylate. ) acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tricyclodecanyl(meth)acrylate, melamine(meth)acrylate, epoxy(meth)acrylate, and other acrylic esters and methacrylic acid Examples include ester, (meth)acrylic acid, styrene, vinyl acetate, (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, and acrylonitrile. These can be used alone or in combination of two or more.

By changing the formulation of red pigment, yellow pigment, etc. in the photoresist material, we have developed a photoresist that has excellent suitability for absorbing the emission wavelength of blue-emitting LEDs and also has excellent suitability for forming partition walls by photolithography at an exposure wavelength of 365 nm. The composition of is designed. If the photoresist is positive, it can be reliably denatured by light irradiation and removed by development, and if it is negative, it can be reliably denatured and cured by light irradiation, and it must have enough sensitivity to mold shapes with high aspect ratios. be. In addition to adjusting the sensitivity of the photoresist, it is also necessary to design the composition by adding a photopolymerization initiator.

Hereinafter, the structural improvements of the optical module and the structural features when applying the optical module to a display device will be mainly explained, and the common explanation of the partition will be omitted. The characteristic feature remains in the partition wall having the above-mentioned characteristics.

Further, although the number of light emitting elements 3 disposed in one block of the optical module 1 is variously explained for each embodiment, there is no limit to the number of light emitting elements 3 in a block, and from one or more to several. The number may be 1,000 pieces. It should be understood that the number of light emitting elements and the number of blocks (the number of divisions in local dimming) can be designed as appropriate depending on the display effect or implementation cost when local dimming is applied.

[Modification of the first embodiment]
FIG. 4 shows a state in which the light emitting element 3 mounted on the optical module 1 of FIG. 1 is electrically connected by a wire 7. As shown in FIG.
As described above, the optical module according to the present invention is capable of controlling light emission on a pixel-by-pixel basis that defines a display pattern by individually driving light-emitting elements in blocks divided by partition walls (or in units of light-emitting elements). It is also possible to apply it in the form of an LED display called micro LED. In FIG. 4, a display pattern consisting of bright and dark pixels of monochromatic light can be constructed.

The upper electrode 17 of the light emitting element 3 is made of, for example, ITO, which is a conductive oxide, and the light emitting elements 3 in the optical module 1 are connected in series by the wire 7 . Reference numeral 6 shown above the light emitting element 3 is a contact hole.

In the lower part of the light emitting element 3 including the lower electrode 8, the bonding layer 14, and the reflective electrode 16, a conductive wiring 9 indicated by a broken line is connected to a circuit section via a switching element such as a thin film transistor (not shown). It is electrically connected to 12. The circuit section 12 individually drives (light emission control) the light emitting elements 3 in block units divided by the partition walls 2 and indicated by the arrangement interval 4 of the partition walls 2.

FIG. 5 is an enlarged view of section C shown in FIG. 4.

The lower electrode 8 of the light emitting element 3 is connected to the reflective electrode 16 via the bonding layer 14.
The reflective electrode 16 is connected to the circuit section 12 by a wiring 9.

For the bonding layer 14, for example, a conductive material that can fuse and electrically connect the lower electrode 8 of the light emitting element and the reflective electrode 16 within a temperature range of 150° C. to 340° C. can be applied. For this conductive material, a conductive filler such as silver, carbon, graphite, etc. may be dispersed in a thermoflowable resin.

Alternatively, the bonding layer 14 may be formed of a low melting point metal such as In (indium), InBi alloy, InSb alloy, InSn alloy, InAg alloy, InGa alloy, SnBi alloy, SnSb alloy, or a ternary or quaternary system of these metals. It can be formed using Since these low melting point metals have good wettability to conductive metal oxides including In oxide, after roughly aligning the lower electrode 8 and the reflective electrode 16, the lower electrode 8 and the reflective electrode 16 are self-aligned. It can be fused coherently. As the energy necessary for fusion, various energies are used, such as heat, pressure, electromagnetic waves, laser light, and a combination of these and ultrasonic waves. Note that the vertical light emitting diode has the advantage that it is easy to repair when a defective junction occurs. Horizontal light emitting diodes with electrodes arranged in the same direction have the disadvantage that it is difficult to inspect the junctions of individual diodes and that the electrodes are easily short-circuited during repair (such as replacing a defective diode). From this point of view, vertical light emitting diodes are preferably used. After film formation such as vacuum film formation, the bonding layer 14 can be patterned by a well-known photolithography method or lift-off means.

For the reflective electrode 16, silver (Ag), a silver alloy, or aluminum (Al), which has a high reflectance of visible light, can be used. Silver has excellent reflectance for visible light, but silver lacks adhesion to many substrate materials and glass substrates. Furthermore, the surface of silver tends to form oxides and sulfides, making electrical mounting difficult.
A three-layer structure in which silver or a silver alloy is sandwiched between conductive oxides containing indium oxide (hereinafter simply referred to as silver conductive oxide sandwiched structure) can compensate for the above-mentioned drawbacks of silver. . The silver conductive oxide sandwiching structure can be used as a conductive wiring of an electric element such as a thin film transistor, and can be specifically applied to the wiring 9.

[Second embodiment]
A second embodiment will be described using FIGS. 6 and 7. The second embodiment relates to a display device (micro LED) to which an optical module having a configuration including a wavelength conversion layer 30 on a light emitting region and a color filter 21 on the wavelength conversion layer 30 is applied. FIG. 6 is a cross-sectional view showing the display device 10 according to the second embodiment. The optical module 1 uses micro-LEDs that individually drive the light-emitting elements 3 (blue-emitting LEDs), and as shown in the plan view of FIG. is a configuration in which one light emitting element 3 is arranged. Each block including the light emitting element 3 and the color cells (R23, G24, B25) of the color filter 21 have a 1:1 correspondence, and the light emitted from the light emitting element 3 in each block is transmitted to the wavelength conversion layer 30 and the color filter 21. Modulated (color tone control). To drive the light emitting element 3, thin film transistors 67 and 68 shown in the circuit diagram of FIG. 7(a) are used.

The light emitted from the light emitting element 3 (blue light emitting LED) is converted into red, green, and blue light by the wavelength conversion layer 30, and further passes through the color filter 21 and enters the observer's eyes. The wavelength conversion layer 30 includes at least red conversion particles and green conversion particles. The wavelength conversion layer 30 may further contain light scattering particles. If the blue wavelength of the blue-emitting LED is offset from the desired blue wavelength, blue conversion particles can be included. As the red conversion particles, green conversion particles, and blue conversion particles, phosphors or quantum dots can be applied. The phosphor can be selected from particle sizes ranging from 1 μm to 30 μm.

In the wavelength conversion layer 30, phosphors or quantum dots are not dispersed unevenly for each color to be wavelength converted, corresponding to each block (color cell of the color filter 21), and the wavelength conversion layer 30 The color filter 21 is designed so that the light that has passed through the filter (from bottom to top in the figure) enters the color filter 21 as white light that is an even mixture of red, green, and blue. In addition, it is effective to mix not only phosphors or quantum dots in the wavelength conversion layer 30 but also light scattering particles for the purpose of ensuring color mixing and controlling the emission range of light passing through. .

The color filter 21 includes, for example, a red filter 23, a green filter 24, a blue filter 25, and a black matrix 20 that partitions them. The color filter 21 and the optical module 1 are bonded together so that the red filter 23, green filter 24, and blue filter 25 face the block containing the light emitting element 3 and correspond to each other in a 1:1 ratio.

FIG. 7B shows a partial plan view of the display device (micro LED) shown in FIG. 6 in which the partition walls 2 and the light emitting elements 3 are arranged in a matrix. FIG. 7A shows thin film transistors (in FIG. 7, two thin film transistors, a first thin film transistor 67 and a second thin film transistor 68 are arranged in one pixel) that drive each light emitting element 3 arranged in a matrix, and a video signal. 8 is a circuit diagram of a micro LED drive illustrating a line 83, a scanning signal line 84, a first power line 85, a second power line 86, a capacitive element 87, and the like. FIG. The video signal line 83 and the scanning signal line 84 are controlled by a video signal control section 81 and a scanning signal control section 82. Since these driving techniques are well known for driving LEDs or organic EL, detailed description thereof will be omitted.

[Modification of second embodiment]
FIG. 8 is a cross-sectional view showing the configuration of a display device (micro LED) 10 according to a modification of the second embodiment, and relates to the display device 10 having a configuration including a wavelength conversion substrate 29 on a light emitting region. The optical module 1 including the light emitting element 3 has the same configuration as the second embodiment.
The wavelength conversion substrate 29 includes, on a transparent substrate 200, a light-blocking partition 34, a red conversion layer 31 that converts blue light into red light, a green conversion layer 32 that converts blue light into green light, and a blue conversion layer 33. The red conversion layer 31, the green conversion layer 32, and the blue conversion layer 33 are partitioned by a light-shielding partition 34. The conversion layers 31, 32, and 33 are arranged so as to face the block including the light emitting element 3 in a 1:1 correspondence.

While the wavelength conversion layer 30 in FIG. 6 is intended for conversion into white light, in the wavelength conversion substrate 29 in FIG. , 33 convert into corresponding colors of red, green, and blue, respectively, and function similarly to a color filter. Therefore, the structure in which the phosphors or quantum dots are unevenly dispersed for each color whose wavelength is converted is different. Similarly to FIG. 6, it is effective to mix light scattering particles into the wavelength conversion layer 30 in FIG. 8 as well.

The blue conversion layer 33 does not require wavelength conversion if the wavelength distribution of the blue light emitted by the light emitting element 3 is a desired wavelength distribution, so it is a layer that simply contains light scattering particles without dispersing phosphor particles. There may be. In addition, in order to improve color purity, a further variation is to insert a color filter (placed between the substrate 200 and the wavelength conversion layer 30) to assist the wavelength conversion layer 30 (31, 32, 33). Conceivable. (not shown)
Since the purpose of the light-shielding partition wall 34 is to prevent light from leaking to adjacent pixels, it can also be a light-reflecting partition wall from the viewpoint of light-shielding.

The red conversion layer 31 is a red conversion layer in which a red phosphor having a particle size of 1 μm to 20 μm is dispersed in a transparent resin. The green color conversion layer 31 is a green color conversion layer in which a green phosphor having a particle size of 1 μm to 20 μm is dispersed in a transparent resin. The blue conversion layer 31 can be a blue conversion layer in which a blue phosphor having a particle size of 1 μm to 20 μm is dispersed in a transparent resin. The blue color conversion layer 31 may be transparent light-scattering particles with a grain size of several μm. Quantum dots may be applied to these color conversion layers.

[Third embodiment]
A third embodiment will be described using FIG. 9. The third embodiment relates to a display device in which an optical module is combined with a display section that defines a display pattern. In the third embodiment, the optical module 1 is used as a backlight unit in an LCD (liquid crystal display).
The display unit that defines the display pattern by the LCD is a liquid crystal panel 38 that includes a transparent substrate 300, a color filter 40, a liquid crystal layer 26, and a thin film transistor array (having a pixel electrode 27 and a common electrode 28) for driving the liquid crystal layer. . In the liquid crystal panel 38, illustrations of a cover glass, a touch panel, a polarizing plate, a retardation plate, an alignment film, a light scattering sheet, a prism sheet, a thin film transistor (third thin film transistor), etc. are omitted.

The optical module 1 includes a light emitting element (LED) 3 and a partition wall 2 arranged on one side of a substrate 100. In the figure, six light-emitting elements 3 are included in a cross-sectional view within an arrangement interval 4 of partition walls 2 that partition a light-emitting region formed by the arrangement of light-emitting elements 3 in blocks. (The number of light emitting elements arranged in the depth direction is not taken into account.) Furthermore, the configuration includes a wavelength conversion layer 30 on the light emitting region. The block units divided by the partition walls 2 have the same configuration as the optical module 1 shown in FIG. 6 except for the number of light emitting elements 3.

Then, the liquid crystal panel 38 and the optical module 1 are arranged such that the pixel part of the liquid crystal panel 38 (the driving area of the liquid crystal layer, and the area where the color cells of the color filter 40 are divided) and the light emitting area of the optical module 1 face each other. A display device is constructed by pasting them together in this way.

The liquid crystal layer 26 is a horizontally aligned liquid crystal driven by a fringe electric field between a pixel electrode 27 and a common electrode 28, which are transparent electrodes such as ITO. The voltage applied to the pixel electrode 27 is controlled by a third thin film transistor (not shown) in units of pixels PX defined by the arrangement interval of the upper electrode 41 formed between the color cells of the color filter 40.

The optical module and display device according to the embodiments described above can be applied in various ways. These applicable electronic devices include mobile phones, portable game devices, personal digital assistants, personal computers, e-books, video cameras, digital still cameras, head-mounted displays, navigation systems, and sound playback devices (car audio, digital audio Examples include players, etc.), copying machines, facsimile machines, printers, multifunction printers, vending machines, automatic teller machines (ATMs), personal authentication devices, data carriers such as IC cards, optical communication devices, and the like. Each of the above embodiments can be used in any combination.

While preferred embodiments of the invention have been described and described above, it is to be understood that these are illustrative of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other changes may be made without departing from the scope of the invention. Accordingly, the invention should not be considered limited by the foregoing description, but rather by the scope of the claims.

1... Optical module 2... Partition wall 3... Light emitting element 4... Partition interval (block)
5 ... Protective layer 6 ... Contact hole 7 ... Wire 8 ... Lower electrode 9 ... Wiring 12 ... Circuit section 13 ... Frame region 14 ... Bonding layer 16 ... Reflective electrode 17 ... Upper electrode 18 ... Video signal line 19 ... Scanning signal line 20 ... Black matrix 21 ... Color filter 23 ... Red filter 24 ... Green filter 25 ... Blue filter 26... Liquid crystal layer 27... Pixel electrode 28... Common electrode 29... Wavelength conversion substrate 30... Wavelength conversion layer layer 31... Red conversion layer 32... Green conversion layer 33 ... Blue conversion layer 34 ... Light-shielding partition wall 35 ... One surface 40 of transparent substrate 200 ... Color filter 41 ... Upper electrode 67 ... First thin film transistor (thin film transistor)
68... Second thin film transistor (thin film transistor)
81... Video signal control section 82... Scanning signal control section 83... Video signal line 84... Scanning signal line 85... First power line 86... Second power line 87... Capacitive elements 100, 200, 300, 400... Transparent substrate 101... One surface PX of transparent substrate 100... Pixel H1... Thickness (height) of partition wall
R... Red phosphor G... Green phosphor B... Blue phosphor

Claims (6)

An optical module having, on one side of a substrate, a light-emitting region in which a plurality of light-emitting elements are arranged, and a partition wall dividing the light-emitting region into units (blocks) each including one or more light-emitting elements, wherein each of the light-emitting elements is in a blue region. It is a blue light-emitting LED that has a light emission peak at the same wavelength as
The optical module is characterized in that the partition wall contains a red pigment and a yellow pigment so as to absorb the light emitted by the blue light emitting LED in the blue region including the light emission peak, and to transmit light with a wavelength of 365 nm. The optical module according to claim 1 , further comprising a wavelength conversion functional layer having a light scattering function on the light emitting region. An optical module comprising a color filter on the wavelength conversion functional layer according to claim 2 . 4. A display device comprising the optical module according to claim 3 , further comprising a circuit unit that controls the light emitting element to emit light and stop emitting light for each block. 4. A display device comprising the optical module according to claim 3 , characterized in that an array substrate comprising a transparent substrate, a liquid crystal layer, and a thin film transistor array for driving the liquid crystal layer is provided at a position facing the color filter. Display device. 3. A display device comprising the optical module according to claim 2, wherein the wavelength conversion functional layer includes a red conversion layer that converts blue light to red light, a green conversion layer that converts blue light to green light, and a blue color conversion layer that converts blue light to green light. A display device comprising a conversion layer.