KR102089335B1 - Display Device and Manufacturing Method of the same - Google Patents

Abstract

The present invention is a substrate; Sub-pixels formed on one surface of the substrate; A protective layer protecting sub-pixels; And a top protective film of a multi-layer formed on a protective film and having different surface characteristics.

Description

Display device and manufacturing method of the same}

The present invention relates to a display device and a method for manufacturing the same.

2. Description of the Related Art With the development of information technology, the market for flat panel display devices, which are a connection medium between users and information, is growing. Accordingly, an organic light emitting display (OLED), a liquid crystal display (LCD), an electrophoretic display (EPD) and a plasma display (PDP) The use of display devices such as this is increasing.

The display device listed above attaches a protective film to protect the surface of the display panel. The protective film serves to prevent damage to the display panel due to external stimuli or impact that may be applied to the upper or lower and upper surfaces of the display panel. The process of attaching the protective film is carried out in such a way that the transparent protective film is pressurized and attached to the upper surface or the upper and lower surfaces of the manufactured display panel by a laminating process.

However, since the conventionally proposed method uses a laminating process, when a foreign material exists between the protective film and the display panel, the pressure applied during the bonding process is transmitted to the display panel through the foreign material to cause a local pressure increase phenomenon.

This pressure increase phenomenon causes damage to the display panel (eg, breakage, cracking, etc.) on the attachment surface of the protective film, thereby deteriorating the characteristics of the device formed inside the display panel and developing into defects such as dark spots in the sub-pixels. In addition, since such defects are not found in the early stages, the display panel gradually increases and gradually increases.

Therefore, since the conventionally proposed process and structure of the protective film is difficult to prevent and discover in advance the damage of the display panel caused or caused by the surface of the protective film, it is required to improve the reliability and yield of the device. .

The present invention for solving the above-described problems of the background technology prevents damage (scratches, breaks, cracks, etc.) of the display panel and also prevents problems such as uneven adhesion or misalignment and can form a protective film on the display panel. It is to provide a structure and method.

The present invention as a means for solving the above problems is a substrate; Sub-pixels formed on one surface of the substrate; A protective layer protecting sub-pixels; And a top protective film of a multi-layer formed on a protective film and having different surface characteristics.

It may be formed on the other surface of the substrate and may include a lower protective film of a multi-layer having different surface properties.

The upper protective film includes a first upper protective film having adhesive or adhesive properties on both sides, and a second upper protective film formed on the first upper protective film and having non-adhesiveness or non-adhesiveness, and the lower protective film is double-sided It may include a first lower protective film having an adhesive or adhesive, and a second lower protective film formed on the first lower protective film and having a non-adhesive or non-adhesive property.

The protective film may be formed of a single organic or inorganic film or an organic-inorganic composite film.

In another aspect, the present invention includes forming sub-pixels on one surface of a substrate; Forming a protective layer to protect the sub-pixels; It provides a method of manufacturing a display device including the step of applying a liquid material on the protective film and curing to form an upper protective film.

After forming the upper protective film, it may include the step of applying a liquid material on the other surface of the substrate and curing to form a lower protective film.

The upper and lower protective films may be formed by a coating method including a spin coater and a slit coater, or a printing method including a screen printer and an ink jet printer.

The upper and lower protective films may include upper and lower protective films of multiple layers having different surface properties.

The upper protective film includes a first upper protective film having adhesive or adhesive properties on both sides, and a second upper protective film formed on the first upper protective film and having non-adhesiveness or non-adhesiveness, and the lower protective film is double-sided It may include a first lower protective film having an adhesive or adhesive, and a second lower protective film formed on the first lower protective film and having a non-adhesive or non-adhesive property.

The protective film may be formed of a single organic or inorganic film or an organic-inorganic composite film.

In the present invention, even when foreign matters that are not completely removed in the display panel manufacturing process remain on the surface of the display panel, the local pressure increase phenomenon that can occur between the protective film attaching process is prevented, thereby preventing damage to the display panel (blemishes, breakage, cracks, etc.). It is also effective in preventing problems such as uneven adhesion and misalignment.

1 is a block diagram schematically showing a flexible display device according to a first embodiment of the present invention.
FIG. 2 is an exemplary view of the sub-pixel shown in FIG. 1.
3 is a view schematically showing a cross-section of a display panel according to a first embodiment of the present invention.
4 is a first exemplary view showing a part of FIG. 3 in detail;
5 is a second exemplary view showing a part of FIG. 3 in detail;
6 is a view for schematically explaining a method of manufacturing a display device according to the prior art.
7 is a view schematically illustrating a method of manufacturing a display device according to a first embodiment of the present invention.
8 is a process flow diagram embodying a manufacturing method of a display device according to a first embodiment of the present invention.
9 is a view schematically showing a cross section of a display panel according to a second embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, specific content for the practice of the present invention will be described.

<First Example>

1 is a block diagram schematically showing a flexible display device according to a first embodiment of the present invention, and FIG. 2 is an exemplary view of the sub-pixel shown in FIG. 1.

As shown in FIG. 1, the flexible display device according to the first embodiment of the present invention includes a timing controller 120, a scan driver 130, a data driver 140, and a display panel 150.

The timing control unit 120 collects device information (Extended Display Identification Data; EDID) including the resolution, frequency, and timing information of the display panel 150 from the external memory unit through an I2C interface or the like, or compensation data. The timing controller 120 outputs a gate timing control signal GDC for controlling the operation timing of the scan driver 130 and a data timing control signal DDC for controlling the operation timing of the data driver 140. The timing controller 120 supplies the data signal DATA with the data timing control signal DDC to the data driver 140.

The data driver 140 samples, latches, and converts and outputs the data signal DATA into a gamma reference voltage in response to the data timing control signal DDC supplied from the timing controller 120. The data driver 140 may be formed of an integrated circuit (IC) and mounted on the display panel 150 or an external substrate connected to the display panel 150. The data driver 140 supplies a data signal DATA to the sub pixels SP included in the display panel 150 through the data lines DL.

The scan driver 130 outputs a scan signal while shifting the level of the gate voltage in response to the gate timing control signal GDC supplied from the timing controller 120. The scan driver 130 may be formed of an integrated circuit and mounted on the display panel 150 or may be mounted on an external substrate connected to the display panel 150. Also, the scan driver 130 may be formed on the display panel 150 in the form of a gate in panel. The scan driver 130 supplies a scan signal to sub-pixels SP included in the display panel 150 through scan lines GL.

The display panel 150 displays an image in response to the scan signal supplied from the scan driver 130 and the data signal DATA supplied from the data driver 140. The display panel 150 includes sub-pixels SP controlling light to display an image. The sub pixels SP included in the display panel 150 may be implemented as an organic light emitting device, a liquid crystal display device, and an electrophoretic display device.

As shown in FIG. 2, one sub-pixel SP is supplied corresponding to the scan signal supplied through the switching transistor SW and the switching transistor SW connected to the scan line GL1 and the data line DL1. A pixel circuit PC operating in response to the data signal DATA is included. The sub-pixel SP is implemented as a liquid crystal display panel including a liquid crystal element or an organic light emitting display panel including an organic light emitting element depending on the configuration of the pixel circuit PC. However, in the following description, it will be described as an example that the sub-pixels SP are made of an organic light emitting device.

On the other hand, a sub-pixel composed of an organic light emitting device is usually composed of a 2T (Transistor) 1C (Capacitor) structure including a driving transistor, a capacitor, and an organic light emitting diode as well as a switching transistor SW. However, when a compensation circuit is added, it is composed of 3T1C, 4T2C, and 5T2C. The sub-pixel having the above configuration is formed in a top-emission method, a bottom-emission method, or a dual-emission method depending on the structure.

In addition, a sub-pixel composed of an organic light-emitting device may be implemented as a sub-pixel structure including a white sub-pixel, a red sub-pixel, a green sub-pixel, and a blue sub-pixel to prevent luminance deterioration and color deterioration while increasing light efficiency. have. In this case, the white sub-pixel, the red sub-pixel, the green sub-pixel and the blue sub-pixel are implemented by using a white organic light emitting diode and an RGB color filter, or the white, red, green and blue light emitting materials included in the organic light emitting diode are used. It is implemented in a manner that is formed by dividing.

Hereinafter, a display panel according to a first embodiment of the present invention will be described. However, in the following description, the use of a flexible substrate to impart ductility to the display panel will be described as an example. However, when ductility is not imparted to the display panel, a non-flexible substrate (eg, glass, etc.) may be used instead of the flexible substrate.

3 is a view schematically showing a cross-section of a display panel according to a first embodiment of the present invention, FIG. 4 is a first exemplary view showing a part of FIG. 3 in detail, and FIG. 5 is a diagram showing a part of FIG. 3 in detail 2 is an example.

As shown in FIG. 3, the display device according to the first exemplary embodiment of the present invention includes a display panel 150, a flexible substrate 151, a protective film 152, an upper protective film 155 and a lower protective film 157. This is included.

The flexible substrate 151 is a material that provides ductility and has excellent resilience, such as polyester sulfone (PES), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), and polycarbonate (PC). It may be one, but is not limited thereto.

Sub-pixels formed of an organic light emitting device are formed on one surface of the flexible substrate 151. Sub-pixels composed of organic light-emitting devices are vulnerable to external air such as oxygen and moisture. Therefore, a protective film 152 capable of sealing the organic light emitting device is formed on the flexible substrate 151.

Referring to the structure of the cross-section of the display panel 150 based on the structure of the sub-pixel composed of the organic light emitting device is as follows.

4 and 5, a switching transistor (not shown), a driving transistor DR, a capacitor (not shown), an organic light emitting diode (OLED), and the like are formed on one surface of the flexible substrate 151. The switching transistor (not shown), the driving transistor DR, the capacitor (not shown), the organic light emitting diode (OLED), and the like are connected to various wires formed on one surface of the flexible substrate 151.

The driving transistor DR includes a gate electrode 161, a semiconductor layer 163, a source electrode 164a and a drain electrode 164b. The gate electrode 161 is formed on one surface of the flexible substrate 151. The first insulating layer 162 is formed on the gate electrode 161. The semiconductor layer 163 is formed on the first insulating film 162. The source electrode 164a and the drain electrode 164b are formed to contact one side and the other side of the semiconductor layer 163. A second insulating film 165 is formed on the source electrode 164a and the drain electrode 164b.

The organic light emitting diode (OLED) includes a lower electrode 166, an organic emission layer 168, and an upper electrode 169. The lower electrode 166 is formed on the second insulating film 165. The lower electrode 166 is formed to be connected to the drain electrode 164b of the driving transistor DR exposed through the second insulating layer 165. The lower electrode 166 is formed separately for each sub-pixel. The lower electrode 166 is selected as an anode electrode or a cathode electrode. The bank layer 167 is formed on the lower electrode 166. The bank layer 167 is a layer that defines the opening area of the sub-pixel. The organic emission layer 168 is formed on the lower electrode 166.

The organic emission layer 168 includes a hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL). At least one functional layer (HIL, HTL, ETL, EIL) other than the emission layer EML of the organic emission layer 168 may be omitted. In addition, the organic emission layer 168 may further include a blocking layer or a barrier layer that controls energy levels of holes and electrons. The upper electrode 169 is formed on the organic emission layer 168. The upper electrode 169 is formed in the form of a face electrode commonly connected to all sub-pixels. The upper electrode 169 is selected as a cathode electrode or an anode electrode.

The passivation layer 152 is formed on the upper electrode 169. The protective layer 152 may be formed of a single organic or inorganic film or an organic-inorganic composite film.

The protective film 152 may be formed in a multi-layer film form as shown in FIG. 4 or a single film form, although not shown. When the protective film 152 is formed in the form of a multilayer film, it may be formed of an organic film and an inorganic film, and when the protective film 152 is formed in a single-layer film form, it may be formed of an organic film or an inorganic film.

The protective film 152 may be formed in the form of an N (N is an integer of 3 or more) layer film as shown in FIG. 5. In this case, the protective layer 152 may be formed of an organic / inorganic composite layer composed of an organic layer 152a, an inorganic layer 152b, an organic layer 152c, and an inorganic layer 152d. Although not shown, the inside of the organic-inorganic composite layer may further include a moisture absorbing layer that absorbs moisture or oxygen.

An upper protective film 155 protecting the upper surface of the display panel is formed on the protective layer 152, and a lower protective film 157 protecting the lower surface of the display panel is formed on the flexible substrate 151. The upper and lower protective films 155 and 157 serve to prevent damage to the display panel due to external stimuli or impact that may be applied to the upper or lower and upper surfaces of the display panel.

Since the conventionally proposed process and structure of the protective film is difficult to prevent and discover in advance the damage of the display panel caused or caused by the surface of the protective film, there is a problem of deteriorating the reliability and yield of the device. The display device according to the first embodiment of the present invention has a different method of forming a protective film to improve this problem.

Hereinafter, the display device according to the prior art and the display device according to the first embodiment of the present invention will be described.

6 is a view schematically illustrating a method of manufacturing a display device according to the prior art, and FIG. 7 is a diagram schematically illustrating a method of manufacturing the display device according to the first embodiment of the present invention.

-Conventional technology-

As shown in FIG. 6, the manufacturing method of the display device according to the prior art forms the upper and lower protective films 156 and 158 on the upper and lower surfaces of the display panel 150 by a laminating process. The upper and lower protective films 156 and 158 are attached to the upper and lower surfaces of the display panel 150 in the form of a film.

When the laminating process is performed, the roller ROL moves while rotating the x1 direction while pressing the protective film in the y1 direction of the stage STG1. For this reason, when a foreign object PT exists between the upper protective film 156 (or lower protective film) and the display panel 150, pressure applied in the process is applied to the display panel 150 through the foreign material PT. Transmitted, causing local pressure increase.

Therefore, this pressure increase phenomenon causes damage (blemishes, breaks, cracks, etc.) of the display panel 150 on the attachment surface of the protective film, deteriorating the characteristics of the device formed inside the display panel 150 and dark spots of the sub-pixels. It develops into the same defect. In addition, since such a defect is not found at the beginning, the display panel 150 continuously increases and gradually increases.

-First Embodiment-

As illustrated in FIG. 7, the method of manufacturing the display device according to the first embodiment of the present invention displays the upper and lower protective films 156 and 158 by a coating process using a spin coater to display the panel 150 It is formed on the upper and lower surfaces.

The upper and lower protective films 156 and 158 are formed on the upper and lower surfaces of the display panel 150 in a state of being manufactured in a liquid form, so a curing process using ultraviolet rays (UV) or the like is required.

When the coating process is performed, the stage (STG2) of the spin coater is rotated (R) so that the translucent resin produced in the liquid form is coated on the upper or lower surface of the display panel 150. For this reason, even if there is a foreign object PT between the upper protective film 156 (or lower protective film) and the display panel 150, no pressure is applied in the process, and thus the display panel 150 through the foreign material PT. It is transmitted to the local pressure increase phenomenon is not caused.

Therefore, the first embodiment of the present invention has the following advantages because the protective film is attached to the display panel 150 in a manner that does not apply pressure.

First, in the first embodiment of the present invention, even when foreign matters that are not completely removed in the display panel manufacturing process remain on the surface of the display panel, it is possible to prevent a local pressure increase phenomenon that may occur between the process of attaching the protective film. Unlike the process of attaching the protective film, it is possible to fundamentally prevent damage caused by foreign matter by coating a layer that functions as a protective film.

Second, since the first embodiment of the present invention is coated with a protective film, damage to the display panel (eg, breakage, cracking, etc.) can be prevented. The conventionally proposed laminating process requires a process such as removal of bubbles when the protective film and the adherend are attached, but the first embodiment of the present invention can omit this. For reference, the conventionally proposed laminating process may cause damage to the interface depending on the state of the adhered surface when removing bubbles.

Third, the first embodiment of the present invention can form a protective film of a single layer with a significantly lower thickness compared to the conventionally proposed laminating process, and also prevents problems such as uneven adhesion or misalignment because it does not use an attachment method. can do. For reference, when the finished display panel is used for a flexible display device, the entire display panel including the substrate has a thickness of less than 100 μm. However, when attaching a protective film to protect it, the thickness of most display panels depends on the thickness of the protective film. In a flexible display device, the thickness of the display panel is a factor that determines the degree of flexibility from a commercialization point of view, and flexibility and thickness have an inverse relationship.

Meanwhile, in the above description, the upper and lower protective films 155 and 157 were described as a coating method using a spin coater. However, the present invention is not limited to this, and may be formed by a coating or printing method using a slit coater, a screen printer, and an ink jet printer. That is, the present invention includes all processes capable of filming a liquid material when forming a protective film.

Hereinafter, a method for manufacturing a display device according to a first embodiment of the present invention will be specified.

8 is a process flow diagram embodying a method of manufacturing a display device according to a first embodiment of the present invention.

As shown in FIG. 8 (a), a flexible substrate 151 is attached to a support substrate GLS, and a transistor unit including a switching transistor, a driving transistor, a capacitor, and various wirings is attached to the flexible substrate 151. Subpixels including (TFT) and an organic light emitting diode (OLED) are formed.

A passivation layer 152 for protecting sub-pixels including the transistor unit TFT and the organic light emitting diode OLED is formed. The flexible circuit board 160 is attached to the flexible board 151. Various devices for driving the display panel 150 are mounted on the flexible circuit board 160. The substrates GLS 151 on which the sub-pixels including the transistor TFT and the organic light emitting diode OLED are formed are mounted on the stage STG2 of the spin coater.

As shown in FIG. 8 (b), the liquid material is coated on the protective film 152, the stage STG2 of the spin coater is rotated, and when the coating is completed, the liquid material is cured. At this time, the liquid material may be coated in a thickness range of 5 ~ 500 ㎛.

 On the other hand, in a state in which desorption of the support substrate GLS is not completed, a liquid material is applied only on the protective film 152 to form the upper protective film 155. This is to prevent damage that may occur in the protective film 152, and is equally applied to the production of a flexible display device as well as a flat panel display device.

As shown in (c) of FIG. 8, the desorption of the support substrate GLS from the flexible substrate 151 is detached, a liquid material is applied to the lower surface of the exposed flexible substrate 151, and the stage of the spin coater ( STG2) is rotated, and when the application is completed, the liquid material is cured.

On the other hand, as described above, the first embodiment of the present invention forms a protective film on the upper and lower surfaces of the display panel by applying and curing the liquid material. Therefore, the liquid crystal material capable of forming a protective film can be cured by ultraviolet (UV) or thermal energy, and any material having light transmittance (preferably high light transmittance) is possible.

In addition, the liquid crystal material capable of forming a protective film is a material having a refractive index of 1.4 to 1.9 after curing, a light isotropic (Rth) of 200 or less, and a transmittance of 80% or more.

<Second Example>

9 is a view schematically showing a cross-section of a display panel according to a second embodiment of the present invention.

As shown in FIG. 9, a heterogeneous protective film is formed on the display panel 150 according to the second embodiment of the present invention. Specifically, the upper and lower protective films 155 and 157 formed on the upper and lower surfaces of the display panel 150 take the following structures.

The upper protective film 155 includes a first upper protective film 155a and a second upper protective film 155b, and the lower protective film 157 includes a first lower protective film 157a and a second lower protective film ( 157b).

The first upper protective film 155a and the second upper protective film 155b have different surface characteristics. That is, the upper and lower protective films 155 and 157 are formed of a heterogeneous liquid material. Specifically, the first upper protective film 155a has adhesive or adhesive properties on both sides, while the second upper protective film 155b does not have adhesive or adhesive properties. That is, the second upper protective film 155b has non-adhesiveness or non-adhesiveness.

The surface characteristics of the first lower protective film 157a and the second lower protective film 157b are the same. The above-described protective film structure is capable of alleviating external stimuli or shocks by the first upper protective film 155a and the first lower protective film 157a.

When the upper and lower protective films 155 and 157 are used as a buffer layer, the thicknesses of the first upper and first lower protective films 155a and 157a are greater than those of the second upper and second lower protective films 155b and 157b. It is better to form thicker.

The upper and lower protective films 155 and 157 formed on the upper and lower surfaces of the display panel 150 according to the second embodiment of the present invention are formed in the same manner as in the first embodiment by applying and curing a liquid material. do. Therefore, the method of forming the upper and lower protective films 155 and 157 is the same as in the first embodiment, and thus is omitted.

As described above, the present invention prevents a local pressure increase phenomenon that may occur between the process of attaching a protective film even when a foreign material that is not completely removed from the display panel manufacturing process remains on the surface of the display panel, thereby damaging the display panel (blemishes, breakage, cracks, etc.) In addition, it is possible to prevent problems such as uneven adhesion and misalignment.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above is in other specific forms without changing the technical spirit or essential features of the present invention by those skilled in the art to which the present invention pertains. It will be understood that it can be practiced. Therefore, the embodiments described above are to be understood in all respects as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the claims below, rather than the detailed description. In addition, all modifications or variations derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

120: timing control unit 130: scan driver
140: data driving unit 150: display panel
151: flexible substrate 152: protective film
155: upper protective film 157: lower protective film
155a: first upper protective film 155b: second upper protective film
157a: first lower protective film 157b: second lower protective film

Claims (10)

Board;
Sub-pixels formed on one surface of the substrate;
A protective layer protecting the sub-pixels; And
It is formed on the protective film and includes an upper protective film of a multi-layer having different surface properties,
The upper protective film
A first upper protective film having adhesive or adhesive properties on both sides, and a second upper protective film formed on the first upper protective film and having non-adhesive or non-adhesive properties,
The first upper protective film and the second upper protective film are formed by coating and curing a heterogeneous liquid material,
The first upper protective film is a thicker display device than the second upper protective film. According to claim 1,
A display device including a lower protective film of a multilayer formed on the other surface of the substrate and having different surface characteristics. According to claim 2,
The lower protective film
A display device comprising a first lower protective film having adhesive or adhesive properties on both sides and a second lower protective film formed on the first lower protective film and having non-adhesive or non-adhesive properties. According to claim 3,
The protective film
A display device formed of a single organic or inorganic film or an organic-inorganic composite film. Forming sub-pixels on one surface of the substrate;
Forming a protective layer protecting the sub-pixels; And
The step of applying a liquid material on the protective film and curing to form an upper protective film,
The upper protective film
A first upper protective film having adhesive or adhesive properties on both sides, and a second upper protective film formed on the first upper protective film and having non-adhesive or non-adhesive properties,
The first upper protective film and the second upper protective film are formed by coating and curing a heterogeneous liquid material,
The first upper protective film is a method of manufacturing a thicker display device than the second upper protective film. The method of claim 5,
After forming the upper protective film,
A method of manufacturing a display device comprising applying a liquid material on the other surface of the substrate and curing to form a lower protective film. The method of claim 6,
The upper and lower protective film
A method of manufacturing a display device, which is formed by a coating method including a spin coater and a slit coater or a printing method including a screen printer and an ink jet printer. . delete The method of claim 6,
The lower protective film
A method of manufacturing a display device comprising a first lower protective film having adhesive or adhesive properties on both sides and a second lower protective film formed on the first lower protective film and having non-adhesive or non-adhesive properties. The method of claim 5,
The protective film
A method of manufacturing a display device, which is formed of a single organic or inorganic film or formed of an organic-inorganic composite film.

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