KR102666767B1 - Array substrate and Reflective display device including the same - Google Patents

Abstract

The present invention provides an array substrate and a reflective display device positioned on a reflector (or reflective electrode) and composed of a hollow particle layer containing hollow particles.
In the present invention, even if the thickness of the hollow particle layer is reduced, the reflectance and white sensitivity of reflected light are improved by the reflector (or reflective electrode) and the hollow particle layer.
Accordingly, the array substrate and the reflective display device have high luminance and contrast ratio and their thickness is reduced.

Description

Array substrate and reflective display device including the same}

The present invention relates to a display device, and to an array substrate having excellent reflectance and whiteness and a reflective display device including the same.

As society has entered a full-fledged information age, the display field, which processes and displays large amounts of information, has developed rapidly, and in response to this, liquid crystal display devices (LCDs) and plasma displays have developed rapidly. Various flat panel displays such as panel device (PDP), field emission display device (FED), organic light emitting diode display device (OELD), etc. have been developed and are in the spotlight.

Such a display device requires a light source inside it. For example, a liquid crystal display device implements an image by placing a backlight unit below the liquid crystal panel and adjusting the transmittance of the liquid crystal panel to light from the backlight unit.

However, there is a problem that power consumption increases to drive the backlight unit, and a reflective display device has been proposed to solve this problem. Additionally, a reflective display device equipped with a white pixel area along with red, green, and blue pixel areas is used to increase luminance.

A reflective electrode is formed in each pixel area, and red, green, and blue color filter layers are formed in each of the red, green, and blue pixel areas. Additionally, only a reflective electrode or a transparent organic insulating layer is formed in the white pixel area.

However, since the WRGB reflective display device with this structure has poor white sensitivity in the white pixel area, the display quality of the reflective display device deteriorates.

The present invention seeks to solve the problem of deterioration of display quality in reflective display devices due to low white sensitivity in the white pixel area.

In order to solve the above problems, the present invention provides an array substrate including a hollow particle layer located on a reflector and containing hollow particles, a transparent electrode covering the hollow particle layer and electrically connected to a thin film transistor, and a reflective array substrate including the same. A display device is provided.

Additionally, the present invention provides an array substrate provided with a reflective electrode electrically connected to a thin film transistor and a hollow particle layer containing hollow particles located on the reflective electrode, and a reflective display device including the same.

At this time, the hollow particle includes a core and a shell surrounding the core, and the refractive index of the shell is greater than the refractive index of the core.

In the array substrate and reflective display device of the present invention, the light scattered by the hollow particles is reflected by the reflector (or reflective electrode), thereby increasing the reflectance in the white pixel area and improving the white sensitivity of the reflected light.

In addition, since the reflectance and white sensitivity are improved even if the thickness of the hollow particle layer is reduced, a thin array substrate and a reflective display device can be provided.

Additionally, because the upper surface of the hollow particle layer is covered with a transparent electrode, damage to the hollow particles due to the formation of the electrochromic layer and/or electrolyte layer can be prevented.

Additionally, since the hollow particle layer scatters light rather than reflecting it, a mask process for the hollow particle layer is possible, and thus the transparent electrode formed on the hollow particle layer and the thin film transistor can be electrically connected. Accordingly, the driving voltage of the reflective display device decreases.

1 is a schematic cross-sectional view of a reflective display device according to a first embodiment of the present invention.
Figure 2 is a schematic cross-sectional view of a reflective display device according to a second embodiment of the present invention.
Figure 3 is a schematic cross-sectional view of a reflective display device according to a third embodiment of the present invention.
Figure 4 is a schematic cross-sectional view of a hollow particle.

The present invention includes a first substrate on which a first pixel area is defined, a thin film transistor located on the first pixel area on the first substrate, and a first electrode covering the thin film transistor and exposing the first electrode of the thin film transistor. A protective layer having a first contact hole, a reflector located on the protective layer, a hollow particle layer including hollow particles located on the reflector and having a second contact hole corresponding to the first contact hole, and An array substrate is provided that covers a hollow particle layer and includes a first transparent electrode electrically connected to the first electrode through the first and second contact holes.

From another perspective, the present invention includes the array substrate described above, a second substrate facing the array substrate, an electrochromic layer located between the array substrate and the second substrate and containing electrochromic particles, and the electric Comprising an electrolyte layer located between the discoloring layer and the second substrate, a counter electrode located between the electrolyte layer and the second substrate, and a second transparent electrode located between the counter electrode and the second substrate. A reflective display device is provided.

From another perspective, the present invention includes a first substrate on which a first pixel area is defined, a thin film transistor located on the first pixel area on the first substrate, and a first layer of the thin film transistor covering the thin film transistor. It includes a protective layer having a contact hole exposing the electrode, a reflective electrode located on the protective layer and connected to the first electrode through the contact hole, and a hollow particle layer located on the reflecting plate and containing hollow particles. An array substrate is provided.

From another perspective, the present invention includes the array substrate described above, a second substrate facing the array substrate, an electrochromic layer located between the array substrate and the second substrate and containing electrochromic particles, and the electric Reflective type comprising an electrolyte layer positioned between the discoloring layer and the second substrate, a counter electrode positioned between the electrolyte layer and the second substrate, and a transparent electrode positioned between the counter electrode and the second substrate. A display device is provided.

In the array substrate and reflective display device of the present invention, the hollow particle includes a core and a shell surrounding the core, and the refractive index of the shell is greater than the refractive index of the core.

In the array substrate and reflective display device of the present invention, the reflector is connected to the first electrode through the first contact hole.

In the array substrate and reflective display device of the present invention, the size of the second contact hole is larger than the first contact hole.

In the array substrate and reflective display device of the present invention, a second pixel region is further defined on the first substrate, and the thin film transistor, the protective layer, the reflector, and the first transparent electrode are included in the second pixel region. and a color filter layer located between the reflector of the second pixel area and the first transparent electrode.

In the array substrate and reflective display device of the present invention, a second pixel region is further defined on the first substrate, the thin film transistor, the protective layer, and the reflective electrode are located in the second pixel region, and the second pixel region is located in the second pixel region. 2. It further includes a color filter layer located on the reflective electrode in the pixel area.

In the array substrate and reflective display device of the present invention, the hollow particle layer and the color filter layer have the same thickness.

Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings.

1 is a schematic cross-sectional view of a reflective display device according to a first embodiment of the present invention.

As shown in FIG. 1, the first reflective display device 100 of the present invention includes a red pixel area (Rp) and a white pixel area (Wp). Additionally, green and blue pixel areas (not shown) may be included to implement a full color image. That is, it includes a color pixel area (red pixel area (Rp), green pixel area, blue pixel area) and a white pixel area (Wp).

The reflective display device 100 includes first and second substrates 110 and 180 facing each other, a reflective electrode 140 located between the first and second substrates 110 and 180, and a red pixel area ( Red color filter layer 142 located in Rp), white pigment layer 150 located in white pixel area (Wp), electrochromic layer 160, electrolyte layer 170, counter electrode 184 and transparent electrode ( 182). Each of the first and second substrates 110 and 180 may be a glass substrate or a plastic substrate.

In addition, a thin film transistor (Tr) for driving each pixel region (Rp, Wp) is connected to the reflective electrode 140 and positioned.

More specifically, a gate wire (not shown) and a data wire (not shown) intersect on the first substrate 110 to define a red pixel area (Crab) and a white pixel area (Wp), and a thin film transistor (Tr) is connected to the gate wiring and data wiring.

The thin film transistor (Tr) includes a gate electrode 112, a semiconductor layer 120, a source electrode 130, and a drain electrode 132. At this time, the gate insulating film 114 is located between the gate electrode 112 and the semiconductor layer 120. The gate insulating film 114 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

The gate electrode 112 is connected to the gate wire, and the source electrode 130 is connected to the data wire. Each of the gate electrode 112, source electrode 130, and drain electrode 132 may be made of a low-resistance metal material such as aluminum or copper.

The semiconductor layer 120 overlaps the gate electrode 112 and is made of an oxide semiconductor material. In contrast, the semiconductor layer 120 has a stacked structure of an active layer (not shown) made of pure amorphous silicon and an ohmic contact layer (not shown) made of impurity-doped amorphous silicon. It may be possible.

The source electrode 130 and the drain electrode 132 are spaced apart from each other and are located on the semiconductor layer 120.

A protective layer 134 is formed that covers the thin film transistor (Tr) and has a drain contact hole 136 exposing the drain electrode 132.

For example, the protective layer 134 may be made of an organic insulating material such as photoacrylic. Additionally, an insulating layer (not shown) made of an inorganic insulating material such as silicon oxide or silicon nitride may be further formed between the protective layer 134 and the source and drain electrodes 130 and 132.

The reflective electrode 140 is connected to the drain electrode 132 through the drain contact hole 136 and is formed on the protective layer 134. For example, the reflective electrode 140 may be made of a conductive material with high reflectivity, such as aluminum.

Alternatively, the reflective electrode 140 may have a multi-layer structure including a transparent conductive material layer and a reflective layer. For example, the reflective electrode 140 has a triple-layer structure of an indium-tin-oxide (ITO) layer, an aluminum-palladium-copper (APC) alloy layer, and an ITO layer. You can have it.

In the red pixel region Rp, a red color filter layer 142 is formed on the reflective electrode 140. Although not shown, green and blue color filter layers are formed on the reflective electrode 140 in the green and blue pixel areas, respectively.

In the white pixel area Wp, a white pigment layer 150 containing titanium oxide (TiO ₂ ) particles 152 is formed on the reflective electrode 140. The titanium oxide particles 152 are white pigments and have excellent whiteness.

The substrate 110 on which a thin film transistor (Tr), a protective layer 134, a reflective electrode 140, and a white pigment layer 150 are formed in the white pixel area (Wp) constitutes an array substrate of the reflective display device 100. do. In addition, the array substrate may include a red pixel region (Rp) in which a thin film transistor (Tr), a protective layer 134, a reflective electrode 140, and a color filter layer 142 are formed to implement a color image, and the red pixel It may further include green and blue pixel areas (not shown) with the same structure as the area Rp.

An electrochromic layer 160 containing electrochromic particles 162 is formed on the red color filter layer 142 and the white pigment layer 150. For example, the electrochromic particles 162 have a structure of a core (not shown) and a shell (not shown) covering the core and made of an electrochromic material.

For example, the core may be made of a transparent conductive oxide selected from In ₂ O ₃ , SnO ₂ , ZnO, ITO, ATO, IZO, and TiO ₂ . Additionally, the shell varies the degree of light absorption depending on the voltage, allowing the electrochromic particles 162 to have transparent or light-blocking characteristics. For example, the shell may be formed from a viologen derivative, however, the materials of the core and shell are not limited thereto.

The electrolyte layer 170 is located on the electrochromic layer 160. For example, the electrolyte layer 170 may be a solid electrolyte containing an ionic salt that is an ion conductor, a plasticizer, and a polymer binder. For example, the ionic salt may be a lithium (Li) salt.

A second substrate 180 on which a second transparent electrode 182 and a counter electrode 184 are formed is located on the electrochromic layer 160.

The second transparent electrode 182 may be made of a transparent conductive material such as ITO or indium-zinc-oxide (IZO). The counter electrode 184 is located between the transparent electrode 182 and the electrolyte layer 170. The counter electrode 184 is formed to ensure that the oxidation-reduction reaction in the electrochromic particles 162 occurs smoothly. For example, the counter electrode 184 may be made of any one of conductive polymers such as PEDOT, ferrocene compound, triphenyl amine, diphenyl amine, and phenoxazine-based polymer.

In the reflective display device 100 having this structure, the degree of light absorption (or transmittance) of the electrochromic particles 162 changes according to voltage application and reflection from the reflective electrode 140 and/or the white pigment layer 150. The video is implemented by .

For example, when no voltage is applied to the reflective electrode 140 and the transparent electrode 182, the electrochromic particles 162 are transparent, and external light is reflected by the reflective electrode 140, giving them a red color. As it passes through the filter layer 142, it displays red. Additionally, in the white pixel area Wp, external light is reflected by the white pigment layer 150 and/or the reflective electrode 140 to display white.

Meanwhile, when voltage is applied to the reflective electrode 140 and the transparent electrode 182, the electrochromic particles 162 are in an opaque state and absorb external light, so that the reflective display device 100 is in a black state. .

At this time, external light is reflected by the white pigment layer 150 containing titanium oxide particles 152, and white sensitivity and reflectance are improved by the titanium oxide particles 152.

However, since the white pigment layer 150 is in contact with the electrochromic layer 160 and is adjacent to the electrolyte layer 170 with only the electrochromic layer 160 interposed, the electrochromic layer 160 and/or the electrolyte layer A problem occurs in which the white pigment layer 150 is damaged by the solvent (or solvents) used in (170). This problem may also occur in the red color filter layer 142.

Additionally, in order to obtain a high reflectance in the white pixel area (Wp) of the reflective display device 100, the thickness of the white pigment layer 150 containing titanium oxide particles 152 must be greatly increased. That is, if the white pigment layer 150 has a thickness of about 2㎛, similar to the red color filter layer 142, there is a limit to obtaining a high reflectance even if the reflective electrode 140 is located below the white pigment layer 150. .

Figure 2 is a schematic cross-sectional view of a reflective display device according to a second embodiment of the present invention.

As shown in FIG. 2, the second reflective display device 200 of the present invention includes a red pixel area (Rp) and a white pixel area (Wp). Additionally, green and blue pixel areas (not shown) may be included to implement a full color image. That is, it includes a color pixel area (red pixel area (Rp), green pixel area, blue pixel area) and a white pixel area (Wp).

The reflective display device 200 includes first and second substrates 210 and 280 facing each other, a reflective electrode 240 located between the first and second substrates 210 and 280, and a red pixel area ( Red color filter layer 242 located in Rp), white pigment layer 250 located in white pixel area (Wp), first transparent electrode 254, electrochromic layer 260, electrolyte layer 270, counter It includes an electrode 284 and a second transparent electrode 282. Each of the first and second substrates 210 and 280 may be a glass substrate or a plastic substrate.

In addition, a thin film transistor (Tr) for driving each pixel region (Rp, Wp) is connected to the second transparent electrode 254 and is located. The thin film transistor (Tr) is also connected to the reflective electrode 240. Alternatively, the reflective electrode 240 may be electrically separated from the thin film transistor (Tr).

On the first substrate 210, a gate wire (not shown) and a data wire (not shown) intersect to define a red pixel area (Grab) and a white pixel area (Wp), and the thin film transistor (Tr) is used for the gate wire and Connected to the data wire.

The thin film transistor (Tr) includes a gate electrode 212, a semiconductor layer 220, a source electrode 230, and a drain electrode 232. A gate insulating film 214 is located between the gate electrode 212 and the semiconductor layer 220.

A protective layer 234 is formed that covers the thin film transistor (Tr) and has a drain contact hole 236 exposing the drain electrode 232, and the reflective electrode 240 is formed through the drain contact hole 236 to expose the drain electrode 232. ) and is formed on the protective layer 234.

The reflective electrode 240 may be made of a conductive material with high reflectivity, such as aluminum. Alternatively, the reflective electrode 240 may have a multi-layer structure including a transparent conductive material layer and a reflective layer. For example, the reflective electrode 240 may have a triple-layer structure of an ITO layer, an APC alloy layer, and an ITO layer.

In the red pixel region Rp, a red color filter layer 242 is formed on the reflective electrode 240. Although not shown, green and blue color filter layers are formed on the reflective electrode 240 in the green and blue pixel areas, respectively.

In the white pixel area Wp, a white pigment layer 250 containing titanium oxide (TiO ₂ ) particles 252 is formed on the reflective electrode 240. The titanium oxide particles 252 are white pigments and have excellent whiteness.

The drain contact hole 236 is formed in the protective layer 234 and the white pigment layer 250 to expose the drain electrode 232. That is, a first contact hole is formed in the protective layer 234, a second contact hole is formed in the white pigment layer 250, and the first and second contact holes form the drain contact hole 236. At this time, the reflective electrode 240 is connected to the drain electrode 232 through the first contact hole.

The first transparent electrode 254 is formed on the red color filter layer 242 and the white pigment layer 250. The first transparent electrode 254 is connected to the drain electrode 232 of the thin film transistor (Tr) through the drain contact hole 236 and is made of a transparent conductive material such as ITO or IZO. That is, the first transparent electrode 254 is electrically connected to the drain electrode 232 through the second contact hole 236.

The color filter layer 242 and the white pigment layer 250 are located between the reflective electrode 240 and the first transparent electrode 254 to form a sandwich structure, thereby protecting the white pigment layer 250.

The substrate 210 on which a thin film transistor (Tr), a protective layer 234, a reflective electrode 240, a white pigment layer 250, and a first transparent electrode 254 are formed in the white pixel area (Wp) is a reflective display device. Construct an array substrate of (200). In addition, the array substrate has a red pixel region (Rp) in which a thin film transistor (Tr), a protective layer 234, a reflective electrode 240, a color filter layer 242, and a first transparent electrode 254 are formed to implement a color image. may include, and may further include green and blue pixel areas (not shown) having the same structure as the red pixel area (Rp).

An electrochromic layer 260 containing electrochromic particles 262 is located on the first transparent electrode 254, and an electrolyte layer 270 is located on the electrochromic layer 260.

Additionally, a second substrate 280 on which a second transparent electrode 282 and a counter electrode 284 are formed is located on the electrochromic layer 260.

In the reflective display device 200 having this structure, the degree of light absorption (or transmittance) of the electrochromic particles 262 changes according to voltage application and reflection from the reflective electrode 240 and/or the white pigment layer 250 The video is implemented by .

For example, when no voltage is applied to the first transparent electrode 254 and the second transparent electrode 282, the electrochromic particles 262 are transparent, and external light is reflected by the reflective electrode 240. It is reflected and passes through the red color filter layer 242 to display red. Additionally, in the white pixel area Wp, external light is reflected by the white pigment layer 250 and/or the reflective electrode 240 to display white.

Meanwhile, when voltage is applied to the first transparent electrode 254 and the second transparent electrode 282, the electrochromic particles 262 are in an opaque state and absorb external light, so that the reflective display device 200 It becomes black.

As described above, the white pigment layer 250 containing titanium oxide particles 252 is covered at the bottom and top by the reflective electrode 240 and the first transparent electrode 254, so the electrochromic layer 260 And/or the problem of the white pigment layer 250 being damaged by the solvent (or solvents) used in the electrolyte layer 270 is prevented. In addition, since the red color filter layer 242 also has its lower and upper sides covered by the reflective electrode 240 and the first transparent electrode 254, damage to the red color filter layer 242 is also prevented.

Additionally, since the white pigment layer 250 has a second thickness t2 greater than the first thickness t1 of the color filter layer 242, sufficient reflectance can be secured in the white pixel area Wp.

However, as the thickness of the white pigment layer 250 increases, a problem of increasing the thickness of the reflective display device 200 occurs.

Additionally, as the thickness of the white pigment layer 250 increases, problems occur in the process of forming the drain contact hole 236 for connecting the first transparent electrode 254 to the drain electrode 232.

That is, in order to form the drain contact hole 236, a mask process must be performed on the red color filter layer 242 and the white pigment layer 250. The white pigment containing titanium oxide particles 252 having reflective properties It is difficult to perform an exposure process on the layer 250. In other words, because the light in the exposure process that must be performed to selectively remove the white pigment layer 250 is reflected by the titanium oxide particles 252, a problem occurs in the mask process for the white pigment layer 250. The drain electrode 232 is not exposed.

Accordingly, voltage is not applied to the first transparent electrode 254 for controlling the degree of light absorption (or transmittance) of the electrochromic particles 262, causing problems in driving the reflective display device 200.

Figure 3 is a schematic cross-sectional view of a reflective display device according to a third embodiment of the present invention.

As shown in FIG. 3, the third reflective display device 300 of the present invention includes a red pixel area (Rp) and a white pixel area (Wp). Additionally, green and blue pixel areas (not shown) may be included to implement a full color image. That is, it includes a color pixel area (red pixel area (Rp), green pixel area, blue pixel area) and a white pixel area (Wp).

The reflective display device 300 includes first and second substrates 310 and 380 facing each other, a reflective electrode 340 located between the first and second substrates 310 and 380, and a red pixel area ( Red color filter layer 342 located in Rp), hollow particle layer 350 located in white pixel area (Wp), first transparent electrode 354, electrochromic layer 360, electrolyte layer 370, counter electrode (384) and a second transparent electrode (382). Each of the first and second substrates 310 and 380 may be a glass substrate or a plastic substrate.

In addition, a thin film transistor (Tr) for driving each pixel region (Rp, Wp) is connected to the second transparent electrode 354 and is located. The thin film transistor (Tr) is also connected to the reflective electrode 340. Alternatively, the reflective electrode 340 may be electrically separated from the thin film transistor (Tr).

On the first substrate 310, a gate wire (not shown) and a data wire (not shown) intersect to define a red pixel area (Rp) and a white pixel area (Wp), and the thin film transistor (Tr) is connected to the gate wire and Connected to the data wire.

The thin film transistor (Tr) includes a gate electrode 312, a semiconductor layer 320, a source electrode 330, and a drain electrode 332. A gate insulating film 314 is located between the gate electrode 312 and the semiconductor layer 320.

A protective layer 334 is formed that covers the thin film transistor (Tr) and has a drain contact hole 336 exposing the drain electrode 332, and the reflective electrode 340 is formed through the drain contact hole 336 to expose the drain electrode 332. ) and is formed on the protective layer 334.

The reflective electrode 340 may be made of a conductive material with high reflectivity, such as aluminum. For example, the reflective electrode 340 may be made of aluminum, copper, or aluminum-palladium-copper (APC) alloy. Alternatively, the reflective electrode 340 may have a multi-layer structure including a transparent conductive material layer and a reflective layer. For example, the reflective electrode 340 may have a triple-layer structure of an ITO layer, an APC alloy layer, and an ITO layer.

The reflective electrode 340 may serve as a reflector without being connected to the drain electrode 332.

In the red pixel region Rp, a red color filter layer 342 is formed on the reflective electrode 340. Although not shown, green and blue color filter layers are formed on the reflective electrode 340 in the green and blue pixel areas, respectively.

In the white pixel area Wp, a hollow particle layer 350 containing hollow particles 352 is formed on the reflective electrode 340. The hollow particle layer 350 further includes photo-sensitive resin to enable a photolithography process.

The hollow particles 352 scatter light and the scattered light is reflected by the reflective electrode 340. At this time, the hollow particles 352 of the present invention have high scattering characteristics, thereby improving the white sensitivity of light reflected by the reflective electrode 340.

The drain contact hole 236 is formed in the protective layer 234 and the hollow particle layer 350 to expose the drain electrode 332. That is, a first contact hole is formed in the protective layer 334, a second contact hole is formed in the hollow particle layer 350, and the first and second contact holes form the drain contact hole 336. At this time, the reflective electrode 340 is connected to the drain electrode 332 through the first contact hole.

The hollow particle layer 350 includes resin (or binder, not shown) and hollow particles 350 dispersed in the resin.

Referring to FIG. 4, which is a schematic cross-sectional view of the hollow particle, the hollow particle 352 includes a core 392 having a first refractive index and a shell 394 surrounding the core 392 having a second refractive index greater than the first refractive index. Includes.

For example, core 392 may be an air layer. Additionally, the shell 394 may have a refractive index of about 1.4 to 1.6 and may be made of a transparent material. For example, the shell 394 may be made of an organic material such as a styrene-based polymer (refractive index 1.59), polymethylmethacrylate (PMMA, refractive index 1.49), or an inorganic material such as silicon oxide (SiO ₂ , refractive index 1.4).

In this way, when the hollow particle layer 350 is disposed on the reflective electrode 340, the reflectance and white sensitivity are improved in the white pixel area (Wp) even if the hollow particle layer 350 has a low thickness. Accordingly, the hollow particle layer 350 and the color filter layer 342 may have substantially the same thickness t1.

The first transparent electrode 354 is formed on the red color filter layer 342 and the hollow particle layer 350. The first transparent electrode 354 is connected to the drain electrode 332 of the thin film transistor (Tr) through the drain contact hole 336 and is made of a transparent conductive material such as ITO or IZO. That is, the first transparent electrode 354 is electrically connected to the drain electrode 332 through the second contact hole 336.

As described above, since the titanium oxide particles 252 of the white pigment layer (250 in FIG. 2) reflect light, a mask process is performed to create a drain contact hole (236 in FIG. 2) in the white pigment layer 250. It is very difficult or impossible to form. Accordingly, the first transparent electrode 254 formed on the white pigment layer 250 cannot be electrically connected to the thin film transistor (Tr).

However, since the hollow particle layer 350 scatters and transmits light, the drain contact hole 336 can be formed in the hollow particle layer 350 through a mask process (photolithography process including an exposure process). Accordingly, the first transparent electrode 254 is electrically connected to the thin film transistor (Tr).

For example, after forming the protective layer 334 on the top of the first substrate 310 on which the thin film transistor (Tr) is formed, a mask process (photolithography process) is performed to create a first contact hole (drain contact hole, 336). A metal material with high reflectivity is deposited and a mask process is performed to form a reflective electrode 340 connected to the drain electrode 332 through the first contact hole.

Meanwhile, by forming a material layer with high reflectance without a first contact hole forming process and patterning it through a mask process, a reflector corresponding to each of the red pixel area (Rp) and the white pixel area (Wp) is formed on the protective layer 334. It can also be formed.

Next, a red color filter layer 342 and a hollow particle layer 350 are formed in the red pixel area (Rp) and the white pixel area (Wp), respectively. The hollow particle layer 350 may be formed by coating a composition containing hollow particles, monomers and/or oligomers, initiators, and solvents and patterning them through a mask process. A second contact hole (drain contact hole) is formed in the red color filter layer 342 and the hollow particle layer 350 through a mask process.

As described above, since the hollow particle layer 350 scatters light rather than reflecting it, a second contact hole can be formed in the hollow particle layer 350 through a mask process.

Since light is scattered by the hollow particle layer 350 in the exposure process of the mask process, the size (planar area) of the second contact hole formed in the hollow particle layer 350 is larger than the first contact hole formed in the protective layer 334. You can. Additionally, the size of the second contact hole formed in the hollow particle layer 350 may be larger than the size of the second contact hole formed in the red color filter layer 342.

Next, the first transparent electrode 354 is formed by depositing a transparent conductive material on the red color filter layer 342 and the hollow particle layer 350 and performing a mask process.

The color filter layer 342 and the hollow particle layer 350 are located between the reflective electrode 340 and the first transparent electrode 354 to form a sandwich structure, thereby protecting the hollow particle layer 350.

The substrate 310 on which a thin film transistor (Tr), a protective layer 334, a reflective electrode 340, a white pigment layer 350, and a first transparent electrode 354 are formed in the white pixel area (Wp) is a reflective display device. Construct an array substrate of 300. In addition, the array substrate has a red pixel region (Rp) in which a thin film transistor (Tr), a protective layer 334, a reflective electrode 340, a color filter layer 342, and a first transparent electrode 354 are formed to implement a color image. may include, and may further include green and blue pixel areas (not shown) having the same structure as the red pixel area (Rp).

An electrochromic layer 360 containing electrochromic particles 362 is located on the first transparent electrode 354, and an electrolyte layer 370 is located on the electrochromic layer 360.

Since the first transparent electrode 354 in contact with the electrochromic layer 360 is electrically connected to the thin film transistor (Tr), the driving voltage for driving the electrochromic layer 360 decreases. Accordingly, the driving voltage and power consumption of the reflective display device 300 are reduced.

Additionally, a second substrate 380 on which a second transparent electrode 382 and a counter electrode 384 are formed is located on the electrochromic layer 360.

Meanwhile, referring again to FIG. 1, the hollow particle layer 350 may be formed instead of the white pigment layer 150. That is, the hollow particle layer 350 is located on the reflective electrode 140 and may be in contact with the electrochromic layer 160. The hollow particle layer 350 of the present invention is located on the reflective electrode 140 and has excellent reflectance and white sensitivity even though it has a low thickness. Therefore, even if the hollow particle layer 350 has substantially the same thickness as the color filter layer 142, the array substrate and the reflective display device have high reflectance and excellent white sensitivity.

In the reflective display device 300 having this structure, the change in the degree of light absorption (or transmittance) of the electrochromic particles 362 according to the application of voltage, light scattering in the hollow particle layer 350, and light scattering in the reflective electrode 340 Images are created through reflection.

For example, when no voltage is applied to the first transparent electrode 354 and the second transparent electrode 382, the electrochromic particles 362 are transparent, and external light is reflected by the reflective electrode 340. It is reflected and passes through the red color filter layer 342 to display red. Additionally, in the white pixel area Wp, external light is scattered by the hollow particle layer 350 and reflected by the reflective electrode 340 to display white.

Meanwhile, when voltage is applied to the first transparent electrode 354 and the second transparent electrode 382, the electrochromic particles 362 are in an opaque state and absorb external light, so that the reflective display device 300 It becomes black.

As described above, since the hollow particle layer 350 containing the hollow particles 352 is covered at the bottom and top by the reflective electrode 340 and the first transparent electrode 354, the electrochromic layer 360 and/ Alternatively, the problem of the hollow particle layer 350 being damaged by the solvent (or solvents) used in the electrolyte layer 370 is prevented. In addition, since the red color filter layer 342 also has its lower and upper sides covered by the reflective electrode 340 and the first transparent electrode 354, damage to the red color filter layer 342 is also prevented.

In addition, in the reflective display device 300 according to the third embodiment of the present invention, since high reflectivity is secured by the hollow particle layer 350 and the reflective electrode 340, the hollow particle layer 350 and the color filter layer 342 ) may have the same thickness (t1). Therefore, there is no problem of increased thickness as in the reflective display device (200 in FIG. 2) according to the second embodiment of the present invention.

In addition, since the hollow particles 352 of the present invention do not reflect light, no problems occur in the formation process of the drain contact hole 336, and accordingly, the reflective display device according to the second embodiment of the present invention ( The driving defect problem as shown in 200) of FIG. 2 does not occur.

That is, the reflective display device 300 according to the third embodiment of the present invention provides high brightness and excellent display due to high reflectance and excellent white sensitivity in the white pixel area (Wp) without increasing the thickness of the display device and driving defects. Can provide quality.

Synthesis of hollow particles

After purging 150 grams of distilled water with nitrogen gas for 30 minutes, 15 grams of styrene and 2.5 grams of acrylic acid were added. Afterwards, 150 grams of distilled water in which potassium persulfate was dissolved at a weight ratio of 0.7 percent was added, the temperature was raised to 70°C while stirring was continued (increasing the temperature by 1°C per minute), and maintained for 8 hours. Afterwards, the residue was removed through centrifugation five times, and 1 gram of the obtained solid was dispersed in 60 grams of distilled water.

Afterwards, it was purged for 30 minutes using nitrogen gas. Add 1.5 grams of divinylbenzene, 1.6 grams of methyl methacrylate, 0.18 grams of acrylic acid, and 0.02 grams of potassium persulfate to the mixture, continue stirring and raise the temperature to 80℃ (increasing by 1.5℃ per minute) for 5 hours. I ordered it. Afterwards, the residue was removed through centrifugation five times and hollow particles were obtained.

Production of reflective display device

MoTi (500Å) and Cu (2000Å) were deposited on the substrate and then patterned through a photolithography process. Silicon nitride (4000Å) was deposited. After depositing a-Si (2000Å), an n+ doping process was performed and patterning was performed through a photolithography process. MoTi (500Å) and Cu (2000Å) were deposited and patterned through a photolithography process.

After forming a silicon nitride layer (3000Å) and a transparent photoacrylic layer (20000Å), a hole was formed. ITO (100Å), APC (1000Å), and ITO (100Å) were sequentially deposited and patterned on the photoacrylic layer.

Afterwards, a hollow particle layer (approximately 2.0㎛) containing the hollow particles synthesized above was applied, and a patterning process and a hole formation process were performed through a photolithography process.

ITO (1000Å) was deposited on the hollow particle layer and patterned to produce an array substrate for a reflective display device.

Experimental Example 1

10 wt% of the hollow particles obtained in the synthesis example, 70 to 80 wt% of propylene glycol methyl ether acetate (PGMEA), 5 to 10 wt% of a mixture of hydroxy alkyl vinyl ether and maleic anhydride monomer (6:4), and 3 to 5 wt of benzyl acrylate. %, 0.5 to 2 wt % of a mixture of triaryl sulfonium salt, diaryl iodonium salt, sulfonate, and N-hydroxysuccinimide triflate, and 0.01 to 1 wt % of triisobutylamine, mixed to make a photo pattern so that the total is 100 wt %. This possible hollow particle composition (10 wt% of hollow particles) was coated to form a hollow particle layer (2.0 ㎛).

Experimental Example 2

In Experimental Example 1, the weight ratio of hollow particles was changed to 20wt%.

Experimental Example 3

In Experimental Example 1, the weight ratio of hollow particles was changed to 30wt%.

Experimental Example 4

In Experimental Example 1, titanium oxide (TiO ₂ ) with a particle size of 300 nm was used instead of hollow particles to form a white pigment layer instead of the hollow particle layer.

Experimental Example 5

In Experimental Example 4, the thickness of the white pigment layer was changed to 10㎛.

Experimental Example 6

In Experimental Example 4, the thickness of the white pigment layer was changed to 70㎛.

Experimental Example 7

An electrochromic layer, an electrolyte layer, and a counter electrode were sequentially formed on the array substrate manufactured in Experimental Example 1, and a substrate on which ITO was deposited was attached to the counter electrode to produce a reflective display device.

Optical properties (reflectance (RY), color coordinates (CIE (x), CIE (y))) of Experimental Examples 1 to 6 above and A4 paper (Comparative Example 1) and metal plate (Comparative Example 2, silver-palladium-copper alloy) White index (WI) ASTM e313 was measured and listed in Table 1 below.

As shown in Table 1, the array substrate on which a hollow particle layer containing hollow particles was formed as in Experimental Examples 1 to 3 has a high reflectance and excellent white sensitivity even when the thickness of the hollow particle layer is small.

The average transmittance (average reflectance) in the reflection mode of Experimental Example 1 and the reflection mode and shading mode of Experimental Example 7 were measured and are listed in Table 2 below.

As shown in Table 2, the reflective display device 300 according to the third embodiment of the present invention has a high reflectance (transmittance) in the reflection mode and a low reflectance in the shading mode. Accordingly, the luminance and contrast ratio of the reflective display device 300 are improved.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art may make various modifications and changes to the present invention without departing from the technical spirit and scope of the present invention as set forth in the claims below. You will understand that you can do it.

100, 200, 300: Reflective display device 110, 210, 310: First substrate
140, 240, 340: Reflecting electrode (reflector) 150, 250: White pigment layer
152, 252: Titanium oxide particles 160, 260, 360: Electrochromic layer
162, 262, 362: electrochromic layer 170, 270, 370: electrolyte layer
180, 280, 380: second substrate
182, 254, 282, 354, 382: transparent electrode
184, 284, 384: counter electrode 350: hollow particle layer
352: Hollow particles

Claims (12)

a first substrate having a first pixel area and a second pixel area defined;
a thin film transistor located on the first substrate, in the first pixel area and the second pixel area;
a protective layer covering the thin film transistor and having a first contact hole exposing a first electrode of the thin film transistor;
a reflector located on the protective layer;
a hollow particle layer located on the reflector, corresponding to the first pixel area, having a second contact hole corresponding to the first contact hole, and containing hollow particles;
a color filter layer located on the reflector, corresponding to the first pixel area, and having a third contact hole corresponding to the first contact hole;
It includes a first transparent electrode covering the hollow particle layer and the color filter layer,
In the first pixel area, the first transparent electrode is electrically connected to the first electrode through the first and second contact holes, and in the second pixel area, the first transparent electrode is connected to the first and third contact holes. electrically connected to the first electrode through a contact hole,
The size of the second contact hole is larger than the third contact hole,
The hollow particle includes a core and a shell surrounding the core, and the refractive index of the shell is greater than the refractive index of the core,
The shell is made of one of styrene-based polymers, polymethylmethacrylate, and silicon oxide (SiO2),
The hollow particle layer is formed only in the first pixel area.
a first substrate on which a first pixel area is defined;
a thin film transistor located on the first substrate and in the first pixel area;
a protective layer covering the thin film transistor and having a contact hole exposing a first electrode of the thin film transistor;
a reflective electrode located on the protective layer and connected to the first electrode through the contact hole;
It is located on the reflective electrode and includes a hollow particle layer containing hollow particles,
The hollow particle includes a core and a shell surrounding the core, and the refractive index of the shell is greater than the refractive index of the core,
The shell is an array substrate made of one of styrene-based polymers, polymethylmethacrylate, and silicon oxide (SiO2).
delete According to claim 1,
The reflector is an array substrate connected to the first electrode through the first contact hole.
According to claim 1,
An array substrate wherein the size of the second contact hole is larger than that of the first contact hole.
delete According to claim 2,
A second pixel area is further defined on the first substrate, and the thin film transistor, the protective layer, and the reflective electrode are located in the second pixel area,
Further comprising a color filter layer located on the reflective electrode in the second pixel area,
The hollow particle layer is formed only in the first pixel area.
According to claim 1 or 7,
An array substrate wherein the hollow particle layer and the color filter layer have the same thickness.
The array substrate of claim 1;
a second substrate facing the array substrate;
an electrochromic layer located between the array substrate and the second substrate and containing electrochromic particles;
an electrolyte layer positioned between the electrochromic layer and the second substrate;
a counter electrode positioned between the electrolyte layer and the second substrate;
A second transparent electrode located between the counter electrode and the second substrate.
A reflective display device including a.
The array substrate of claim 2;
a second substrate facing the array substrate;
an electrochromic layer located between the array substrate and the second substrate and containing electrochromic particles;
an electrolyte layer positioned between the electrochromic layer and the second substrate;
a counter electrode positioned between the electrolyte layer and the second substrate;
A transparent electrode located between the counter electrode and the second substrate
A reflective display device including a. delete delete

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