KR102188938B1 - Inkjet printing apparatus discharging ocr drolpet over foldable oled display panel - Google Patents

Abstract

The present invention relates to an inkjet printing apparatus for discharging OCR droplets on a foldable OLED display panel, which controls to discharge a first OCR droplet when a first head is positioned on a bending area of a foldable OLED display panel, and to discharge a second OCR droplet when a second head is positioned on the bending area of the foldable OLED display panel, so as to enable the special treatment on the bending area, so that the durability and visibility of a foldable smartphone can be increased.

Description

Inkjet printing device that discharges OCR droplets on a foldable OLED display panel {INKJET PRINTING APPARATUS DISCHARGING OCR DROLPET OVER FOLDABLE OLED DISPLAY PANEL}

This document relates to an inkjet printer, and specifically, to inkjet printing for a foldable OLED display panel.

Recently, a display device using an organic light emitting diode (OLED) is attracting attention. The organic light-emitting display device has a self-emission characteristic, and unlike a liquid crystal display device, it does not require a separate light source, and thus the thickness and weight can be reduced. The organic light emitting display device exhibits high quality characteristics such as low power consumption, high luminance, and fast reaction speed.

In the organic light-emitting display device, in order to protect the organic light-emitting display panel, a transparent protective cover is mounted on the organic light-emitting display panel and attached thereto. One of the adhesives used at this time is optically clear adhesive (OCA). The optically transparent adhesive (OCA) is usually in the shape of a film, and due to the thickness of the adhesive itself, not only increases the overall thickness of the panel, but also has a problem of inferior adhesion.

Recently, optically clear resin (OCR) is used to bond the protective cover to the organic light emitting display panel. Inkjet printing is a non-contact patterning technology, and it is possible to form a pattern by forming droplets of several tens of µm at a desired location, and unlike other printing technologies, ink consumption is low and the number of processes can be drastically reduced. Recently, folding smartphones (eg, Galaxy Fold) are being released. However, the folded portion (bending area) of the smartphone screen may cause defects due to continuous folding, and thus visibility may decrease. Such a defect may have a problem in the transparent protective cover (protective glass) or the hinge, but there may be a problem in the durability of a bonding agent such as resin used when bonding the transparent protective cover and the display panel. Therefore, it is necessary to develop a special inkjet printing device to solve this problem.

Korean Patent Publication (Publication Publication No. 10-2014-0140742, "Flexible Display Device and Method of Manufacturing a Flexible Display Device") has a hinge interposed therebetween, and a first display structure including nanoparticles and silicon When a flexible display device including a second display structure is disclosed, and a user deforms the flexible display device such as folding, bending, or rolling the flexible display device in a predetermined direction, the conventional flexibility Since the display device is more easily deformable than the display device, a technology capable of preventing damage to a flexible display device and increasing portability has been disclosed. However, there is no disclosed technology for solving the problem of poor visibility or durability of the folded area by using the folded smartphone for a long time.

An object of the present invention is to enhance durability and visibility of a bending area of a foldable display panel.

In the inkjet printing apparatus for discharging OCR droplets on a folded OLED display panel composed of a bending area and a non-bending area according to an aspect for achieving this purpose,

A first head that moves on the OLED display panel and discharges the first OCR droplet,

A second head that moves on the OLED display panel and discharges second OCR droplets having different physical properties from the first OCR droplets, and

A control unit for driving and controlling OCR droplet discharge of the first head and the second head,

The control unit,

When the first head is placed on the bending area of the foldable OLED display panel, the first OCR droplet is discharged, and the second head is placed on the bending area of the foldable OLED display panel. An inkjet printing device that controls to eject an enemy is configured.

In the present invention, when an inkjet printing device ejects OCR on a display panel, the bending area and the non-bending area are separated, and the bending area discharges OCR of special properties different from the non-bending area, thereby enhancing the durability of the frequently folded bending area. And improve visibility.

1 is a diagram illustrating a general foldable OLED display panel.
FIG. 2 is a diagram illustrating an inkjet printing apparatus for discharging OCR droplets on a folded OLED display panel showing a cross section of A-A' of FIG.
3 is a diagram illustrating an inkjet printing apparatus for discharging OCR droplets on a foldable OLED display panel according to another exemplary embodiment.
4 is a diagram illustrating an inkjet printing apparatus for discharging OCR droplets on a folded OLED display panel according to another exemplary embodiment.
5 is a diagram illustrating bonding of an OLED display panel to which OCR is applied with a protective cover.

Hereinafter, the present invention will be described in detail so that those skilled in the art can easily understand and reproduce the present invention through preferred embodiments described with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the embodiments of the present invention, the detailed description will be omitted. Terms used throughout the specification of the present invention are terms defined in consideration of functions in the embodiments of the present invention, and can be sufficiently modified according to the intention and custom of the user or operator. It should be made based on the contents of

In addition, the above-described and additional aspects of the invention will become apparent through the following embodiments. Aspects or configurations of the embodiments described selectively in the present specification may be freely combined with each other, even if they are shown as a single unified configuration in the drawings, unless otherwise stated, unless otherwise indicated in technical contradiction to those skilled in the art. I understand.

Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all the technical spirit of the present invention, and thus various alternatives that can be substituted for them at the time of application It should be understood that there may be equivalents and variations.

1 is a diagram illustrating a general folded OLED display panel. As shown, the folded OLED display panel 100 may include a non-bending area 110, a bending area 120, and a bezel area 130.

The non-bending area 110 (NBA) is an area that is not folded and means an area in which the display is activated. The non-bending area can occupy most of the area of the OLED display panel.

The bending area 120 (BA) is an area that is positioned between and folded between the non-bending areas, and likewise means an area in which the display is activated. The bending area may be located along the Y axis of the OLED display panel 100. An RGB color filter may be formed in the non-bending area 110 (NBA) and the bending area 120 (BA) to be activated. The bending area BA may have a width of several mm or less.

The bezel area 130 refers to an area in which the display is not activated because it is located at the edge of the non-bending area and the bending area. The bezel area 130 may form a part of the housing. The bezel area 130 may not be provided according to the recent trend of expanding the edge area of the smartphone to the display active screen.

The OLED display panel 100 may be positioned on the stage of the inkjet printing apparatus and moved along the Y axis.

FIG. 2 is a diagram illustrating an inkjet printing apparatus for discharging OCR droplets on a foldable OLED display panel showing a cross section of A-A' of FIG. 1. As shown, the inkjet printing apparatus 200 is composed of a plurality of heads 210 and 220, and the head may move in the X axis on the foldable OLED display panel 100. There may be several to tens of heads in the head unit. One head has a bar shape and may be provided with tens to hundreds of nozzles to discharge droplets.

The head moves on the OLED display panel and moves on the first head 210 that discharges the first OCR droplet, and the OLED display panel (organic light emitting display panel), and has physical properties from the first OCR droplet. It may be divided into a second head 220 that discharges another second OCR droplet.

OCR (Optically Clear Resin) may be any one of acrylic, epoxy, silicone, and rubber resins or a mixture thereof, and UV (Ultra-violet) curable resins are preferred. OCR can function to be filled between the protective cover and the OLED display panel by mounting a protective cover and bond both.

Since the second OCR 2 has stronger elasticity and higher durability after being hardened than the first OCR 1, the possibility of damage may be reduced due to continuous repeated bending. That is, the second OCR (2) may have a greater modulus than the first OCR (1). Accordingly, the first head 210 and the second head 220 may discharge droplets accordingly. The first OCR (1) and the second OCR (2) are provided in a reservoir (not shown) of the inkjet printing apparatus 200, respectively, and the reservoir is the first head 210 and the second head Each may be connected to 220 by a pipe.

The movement of the head and control of the OCR ejection drive are controlled by a control unit (not shown) of the inkjet printing apparatus 200. The control unit may drive and control the ejection of OCR droplets of the first head and the second head, and may be installed adjacent to the head to move along with the movement of the head. The discharge drive control may include control of a discharge amount, frequency, and speed of a droplet in addition to discharge on/off.

The plurality of heads 210 and 220 may discharge (dispensing) OCR droplets to stack OCRs on the OLED display panel 100 in the Z-axis direction. The OCR is stacked on the non-bending region 110 and the bending region 120. The inkjet printing apparatus 200 may or may not allow the OCR to be stacked on the bezel area 130.

The bending area 120 may be folded by a hinge method, or a synthetic resin having elastic force may be used, and there is no limitation on the implementation method.

3 is a diagram illustrating an inkjet printing apparatus for discharging OCR droplets on a folded OLED display panel according to another exemplary embodiment. As illustrated, the inkjet printing apparatus 200 may control ejection driving so that the edge region E of the bending region 120 of the OLED display panel overlaps the first OCR and the second OCR. The boundary area between OCR 1 and OCR 2 may form various cross-sectional shapes through discharge amount control. For example, in the edge area (E), the first OCR is stacked first and the second OCR is stacked after that, so that the A-A' cross-section of the second OCR (2) has a reverse bridge shape. can do. Free folding may be achieved by stacking the second OCR 2 having a larger modulus than the first OCR 1 in this shape. The second OCR (2) may be more expensive than the first OCR (1).

As shown, the first head 210 and the second head 220 are provided with nozzles (not shown), respectively, at the effective areas D and D'in which droplets are discharged and the left and right edges of the effective area. It is provided and may be divided into non-effective areas (d, d') in which droplets are not discharged.

In the inkjet printing apparatus according to another embodiment, the length of the second head (D'+2d') may be shorter than the length of the first head (D+2d). Accordingly, the head may be arranged so that it is advantageous to apply the second OCR 2 to the bending region 120 and the first OCR 1 to the non-bending region 110.

In the inkjet printing apparatus according to another embodiment, at least a portion of the non-effective area d of the first head 210 and the non-effective area d′ of the second head 220 overlap each other ( Overlapped). In FIG. 3, an ineffective area d of the first head 210 and an ineffective area d'of the second head 220 are overlapped by an O area.

As a result, precise discharge of the first head 210 and the second head 220 from the edge region E of the bending region 120 is possible.

A plurality of nozzles provided in one head may be controlled to have different discharge frequencies. For example, the edge nozzles of the effective areas D and D'in which the droplets are ejected may have a lower frequency (the number of droplet ejections/second) than the center nozzle.

4 is a diagram illustrating an inkjet printing apparatus for discharging OCR droplets on a folded OLED display panel according to another exemplary embodiment. As shown, in the inkjet printing apparatus 200, the first head 210 applies the first OCR 1 to the bending area 120 first, and then the second head 220 applies the bending area. It can be controlled to apply the second OCR (2) to 120. Accordingly, the first OCR and the second OCR 2 can be controlled to be stacked in the bending area 120.

5 is a view for explaining bonding of an OLED display panel to which OCR is applied with a protective cover. As shown, a protective cover on the OLED display panel 100 on which the second OCR 2 is applied to the bending area 120 and the first OCR 1 is applied to the non-bending area 110 300) may be positioned, and the OLED display panel 100 or the protective cover 300 may be moved in the Z direction to bond both. Lamination can be performed using a laminator. The protective cover 300 functions to protect the OLED display panel 100, and is preferably made of glass or synthetic resin, and is transparent to function as a window. As shown, the protective cover 300 may or may not have an orthogonal shape with an edge portion. The protective cover 300 may be divided into a non-bending area 301 and a bending area 302. A smartphone may be manufactured with the inkjet printing device 200.

1: first OCR
2: second OCR
100: folding OLED display panel
110: non-bending area
120: bending area
130: bezel area
200: inkjet printing device
210: first head
220: second head
300: protective cover
301: non-bending area of the protective cover
301: bending area of the protective cover

Claims (4)

In the inkjet printing apparatus for discharging OCR droplets on a folded OLED display panel consisting of a bending area and a non-bending area,
A first head moving on the OLED display panel and discharging the first OCR droplet;
A second head having a length shorter than that of the first head, moving on the OLED display panel, and discharging second OCR droplets having higher elasticity after curing than the first OCR droplets; And
A control unit for driving and controlling OCR droplet discharge of the first head and the second head;
The control unit is:
When the first head is placed on the bending area of the foldable OLED display panel, the first OCR droplet is discharged, and the second head is placed on the bending area of the foldable OLED display panel. Eject the enemy,
An inkjet printing apparatus that discharges the edge region of the bending region so that the first OCR and the second OCR are overlapped and stacked, and the stacked cross section of the bending region has a reverse bridge shape. The method of claim 1,
An inkjet printing apparatus in which at least a portion of the non-effective area (d) of the first head 210 and the non-effective area (d') of the second head 220 are overlapped with each other. A smartphone manufactured with the inkjet printing device of claim 1. delete

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