CN116267006A

CN116267006A - Organic light emitting display device

Info

Publication number: CN116267006A
Application number: CN202211645238.0A
Authority: CN
Inventors: 昌秀真; 李圭焕; 尹智洙
Original assignee: LG Display Co Ltd
Current assignee: LG Display Co Ltd
Priority date: 2021-12-17
Filing date: 2022-12-16
Publication date: 2023-06-20
Also published as: KR20230092485A

Abstract

An organic light emitting display device comprising: a substrate including first to third sub-pixels; the first light emitting diode to the third light emitting diode are arranged on the substrate and are respectively positioned in the first sub-pixel to the third sub-pixel; and a transmittance control layer arranged to correspond to a transmission direction of light emitted from the first light emitting diode to the third light emitting diode and including a gray pattern, wherein the gray pattern is arranged to cover the lens-shaped transparent pattern and has different thicknesses according to a region in contact with the transparent pattern.

Description

Organic light emitting display device

Cross Reference to Related Applications

The present application claims priority from korean patent application No. 10-2021-0181913 filed on the year 2021, month 12, 17, the entire contents of which are incorporated herein by reference as if fully set forth herein for all purposes.

Technical Field

The present invention relates to an organic light emitting display device having a limited viewing angle.

Background

Recently, as society has entered the general information age, interest in information displays that process and display a large amount of information has increased, and as demand for using portable information media has increased, various light and thin flat panel displays have been developed and have been attracting attention.

In particular, among various flat display devices, an organic light emitting display device (OLED) is a self-luminous device and does not require a backlight used in a liquid crystal display device (LCD) which is a non-self-luminous device, and thus can be light and thin.

Such organic light emitting display devices are widely used as display screens for various products (including not only portable electronic devices such as mobile communication terminals, electronic notebooks, electronic books, PMPs such as portable multimedia players, navigation, UMPCs such as ultra mobile computers, mobile phones, smartphones, tablet computers, and telephone watches, but also televisions, notebook computers, monitors, and ATMs).

Meanwhile, a general organic light emitting display device does not have a viewing angle limitation. Recently, however, viewing angle restrictions are required for privacy protection and information protection reasons.

For example, devices such as ATM in financial institutions, car navigation, notebook computers, tablet computers need to limit viewing angle in the left-right direction or up-down direction to protect privacy.

In particular, in the case of car navigation, when the up-down viewing angle of the organic light emitting display device is wide, an image displayed on the organic light emitting display device may reduce the attention of the driver and interfere with driving. Further, when driving at night, an image displayed on the organic light emitting display device may be reflected onto a front windshield of the vehicle, which may adversely affect safe driving of the driver.

Therefore, recently, a structure of applying a light control film to limit a viewing angle has been proposed, but the film has a high cost, which increases the manufacturing cost of the organic light emitting display device, and the thickness of the organic light emitting display device increases due to the addition of the film. Therefore, it is difficult to realize a light and thin organic light emitting display device that has been recently demanded.

Disclosure of Invention

Accordingly, the present invention is directed to an organic light emitting display device that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An advantage of the present invention is to provide an organic light emitting display device having a limited viewing angle.

Another advantage of the present invention is to provide an organic light emitting display device having reduced cost and simple structure.

Still another advantage of the present invention is to provide an organic light emitting display device that can adjust a viewing angle and prevent reflection of an image on a front windshield of a vehicle from interfering with a driver's view when the organic light emitting display device is mounted on the vehicle.

Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the disclosure. These and other advantages of the present disclosure will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purpose of the present disclosure, as embodied and broadly described herein, an organic light emitting display device includes: a substrate including first to third sub-pixels; the first light emitting diode to the third light emitting diode are arranged on the substrate and are respectively positioned in the first sub-pixel to the third sub-pixel; and a transmittance control layer arranged to correspond to a transmission direction of light emitted from the first light emitting diode to the third light emitting diode and including a gray pattern, wherein the gray pattern is arranged to cover the lens-shaped transparent pattern and has different thicknesses according to a region in contact with the transparent pattern.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the principles of the disclosure. In the drawings:

fig. 1 is a plan view illustrating a plurality of sub-pixels in an organic light emitting display device according to an embodiment of the present invention;

fig. 2 is a cross-sectional view taken along line II-II' of fig. 1, illustrating a structure of a unit pixel including three sub-pixels of an organic light emitting display device according to an embodiment of the present invention;

fig. 3 is a view showing an optical path of an organic light emitting display device according to an embodiment of the present invention;

fig. 4A is a graph showing transmittance according to the wavelength of light;

FIG. 4B is a graph of light efficiency resulting from recycling as a function of viewing angle;

fig. 5A is a cross-sectional view showing a vertical viewing angle of one sub-pixel of an organic light emitting display device according to an embodiment of the present invention;

fig. 5B is a cross-sectional view showing a horizontal viewing angle of one sub-pixel of an organic light emitting display device according to an embodiment of the present invention;

fig. 6A is a front view illustrating the shape of a transparent pattern according to an embodiment of the present invention;

fig. 6B is a cross-sectional view showing a structure of a unit pixel including three sub-pixels in a horizontal direction of a transparent lens in an organic light emitting display device according to an embodiment of the present invention; and

fig. 7 is a graph showing light transmittance of each sub-pixel in the horizontal direction.

Detailed Description

Hereinafter, embodiments according to the present invention are described with reference to the accompanying drawings.

Fig. 1 is a plan view illustrating a plurality of sub-pixels in an organic light emitting display device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II' of fig. 1, illustrating a structure of a unit pixel including three sub-pixels of an organic light emitting display device according to an embodiment of the present invention.

As shown in fig. 1 and 2, in the organic light emitting display device 100 according to the first embodiment of the present invention, one unit pixel P may include a red sub-pixel R-SP, a green sub-pixel G-SP, and a blue sub-pixel B-SP. Each of the sub-pixels R-SP, G-SP, and B-SP may include a light emitting area EA, and a bank 119 may be disposed along an edge of the light emitting area EA to form a non-light emitting area NEA.

In this case, the red, green, and blue sub-pixels R-SP, G-SP, and B-SP may be alternately disposed in the horizontal direction, and each of the plurality of red, green, and blue sub-pixels R-SP, G-SP, and B-SP may be arranged in the vertical direction.

Here, for convenience of explanation, a structure in which the respective sub-pixels R-SP, G-SP, or B-SP are arranged in a stripe form is shown. However, each of the sub-pixels R-SP, G-SP, or B-SP may be formed of a polygon, but is not limited thereto, and may have various shapes such as a circle, an ellipse, and a semi-ellipse.

In addition, the sub-pixels R-SP, G-SP, and B-SP are shown to be disposed side by side with the same width, but the sub-pixels R-SP, G-SP, and B-SP may include various structures having different widths.

At this time, the switching thin film transistor STr and the driving thin film transistor DTr may be disposed on the non-light emitting region NEA of each of the sub-pixels R-SP, G-SP and B-SP. A light emitting diode E including a first electrode 111, an organic light emitting layer 113, and a second electrode 115 may be disposed on the light emitting area EA of each of the sub-pixels R-SP, G-SP, and B-SP.

Here, the switching thin film transistor STr and the driving thin film transistor DTr may be connected to each other, and the driving thin film transistor DTr may be connected to the light emitting diode E.

In more detail, the gate line GL, the data line DL, and the power line VDD may be disposed on the substrate 101 to define each of the sub-pixels R-SP, G-SP, and B-SP.

The switching thin film transistor STr and the driving thin film transistor DTr may be located on the switching region TrA of the non-light emitting region NEA of each of the sub-pixels R-SP, G-SP and B-SP. The switching thin film transistor STr may be formed in a region where the gate line GL and the data line DL cross each other, and the switching thin film transistor STr may be used to select each of the sub-pixels R-SP, G-SP, and B-SP.

The switching thin film transistor STr may include a gate electrode SG branched from the gate line GL, a semiconductor layer (not shown), a source electrode SS, and a drain electrode SD.

The driving thin film transistor DTr may be used to drive the light emitting diode E of each of the sub-pixels R-SP, G-SP, and B-SP selected by the switching thin film transistor STr. The driving thin film transistor DTr may include a gate electrode DG connected to the drain electrode SD of the switching thin film transistor STr, a semiconductor layer 103, a source electrode DS connected to the power line VDD, and a drain electrode DD.

At this time, the semiconductor layer 103 may be made of silicon, and may include an active region 103a in which a channel is formed at a central portion thereof, and a source region 103b and a drain region 103c doped with high-concentration impurities at both side portions of the active region 103 a.

The gate insulating layer 105 may be located between the semiconductor layer 103 and the gate electrode DG, and the first interlayer insulating layer 109a may be located between the gate electrode DG and the source and drain electrodes DS and DD. In this case, the first interlayer insulating layer 109a and the gate insulating layer 105 may include a first semiconductor layer contact hole 116 and a second semiconductor layer contact hole 116 exposing the source region 103b and the drain region 103c.

Accordingly, the source DS and the drain DD may contact the source region 103b and the drain region 103c of the semiconductor layer 103 through the first semiconductor layer contact hole 116 and the second semiconductor layer contact hole 116, respectively.

The second interlayer insulating layer 109b may be located on the source and drain electrodes DS and DD and the first interlayer insulating layer 109a exposed between the source and drain electrodes DS and DD.

The first electrode 111 of the light emitting diode E may be located on the second interlayer insulating layer 109b, and the first electrode 111 may be connected to the drain electrode DD of the driving thin film transistor DTr through a drain contact hole PH provided in the second interlayer insulating layer 109 b.

For example, the first electrode 111 may be made of a material having a relatively high work function and form an anode of the light emitting diode E. The first electrode 111 may be disposed for each of the sub-pixels R-SP, G-SP, or B-SP, and the bank 119 may be located between the first electrodes 111 of the sub-pixels R-SP, G-SP, and B-SP.

The first electrode 111 may have a separate structure for each of the sub-pixels R-SP, G-SP, and B-SP, and the bank 119 serves as a boundary of each of the sub-pixels R-SP, G-SP, and B-SP.

In addition, the organic light emitting layer 113 may be positioned on the first electrode 111. The organic light emitting layer 113 may be formed by a single layer made of a light emitting material. Alternatively, the organic light emitting layer 113 may be composed of a plurality of layers of a hole injection layer, a hole transport layer, a light emitting material layer, an electron transport layer, and an electron injection layer to improve light emitting efficiency.

The second electrode 115 forming the cathode may be located on the entire surface of the organic light emitting layer 113, and the second electrode 115 may be made of a material having a relatively small work function.

In the organic light emitting display device 100, when a predetermined voltage is applied to the first electrode 111 and the second electrode 115 according to a selected signal, holes injected from the first electrode 111 and electrons injected from the second electrode 115 are transferred to the organic light emitting layer 113 to form excitons, and when the excitons are converted from an excited state to a ground state, light is generated in the form of visible light and emitted.

Here, since the organic light emitting display device 100 according to an embodiment of the present invention may be a top emission type, light emitted from the organic light emitting layer 113 may be emitted through the second electrode 115, so that the organic light emitting display device 100 finally achieves an arbitrary image.

The top emission type display device may have the switching thin film transistor STr and the driving thin film transistor DTr disposed under the bank 119 and the first electrode 111 in a wide range, and thus has an advantage in that the design area of the thin film transistors STr and DTr is wider than that of the bottom emission type display device.

In this case, the first electrode 111 as an anode may be formed of a metal material having high reflectivity, such as aluminum (Al), silver (Ag), or a stacked structure of aluminum (A1) or silver (Ag) and ITO. The second electrode 115 as a cathode may be formed of a transparent metal material such as ITO or IZO, or may be formed of a semi-transmissive metal thin film using magnesium (Mg), silver (Ag), or both of magnesium (Mg) and silver (Ag), so that light emitted from the organic light emitting layer 113 can be transmitted.

A passivation layer 102 and a package substrate 104 in the form of a thin film may be sequentially disposed on the thin film transistors STr and DTr and the light emitting diode E. The passivation layer 102 may serve to prevent moisture from penetrating to each of the sub-pixels R-SP, G-SP, and B-SP, and protect the organic light emitting layer 113 from external moisture or oxygen.

In addition, the passivation layer 102 may serve to protect the thin film transistors STr and DTr and the light emitting diode E from external impact. In addition, the passivation layer 102 may be used to bond the substrate 101 and the package substrate 104.

Accordingly, the organic light emitting display device 100 may be packaged. Here, in the organic light emitting display device 100 according to an embodiment of the present invention, the organic light emitting layer 113 emitting light of different colors for each of the sub-pixels R-SP, G-SP, and B-SP may be formed.

That is, in the red subpixel R-SP, the organic light emitting layer 113 emitting red light may be located in the entire light emitting area EA of the red subpixel R-SP. In the green sub-pixel G-SP, the organic light emitting layer 113 emitting green light may be located in the entire light emitting area EA of the green sub-pixel G-SP. In the blue sub-pixel B-SP, the organic light emitting layer 113 emitting blue light may be located in the entire light emitting area EA of the blue sub-pixel B-SP.

Accordingly, the organic light emitting display device 100 according to an embodiment of the present invention may emit light of R color, G color, and B color from the respective sub-pixels R-SP, G-SP, and B-SP to realize full color with high brightness.

In particular, in the organic light emitting display device 100 according to an embodiment of the present invention, the transmittance control layer 200 may be arranged to correspond to a transmission direction of light emitted from the organic light emitting layer 113.

The transmittance control layer 200 may include a black matrix 201 arranged to correspond to the non-light emitting region NEA of each of the sub-pixels R-SP, G-SP, and B-SP, and a transparent pattern 203 arranged to correspond to the light emitting region EA of each of the sub-pixels R-SP, G-SP, and B-SP, and may further include a gray pattern 205 covering the transparent pattern 203.

The black matrix 201 may block light (L2 and L3 of fig. 3) incident from the organic light emitting layer 113 at an angle greater than or equal to a specific angle with respect to a vertical plane of the organic light emitting display device 100. In this way, in the organic light emitting display device 100 according to the embodiment of the present invention, the viewing angle is limited.

In particular, the black matrix 201 according to an embodiment of the present invention may further include a reflective layer 201a such that light (L3 of fig. 3) emitted from each of the sub-pixels R-SP, G-SP, and B-SP is reflected and recovered, and light efficiency is further improved. This is described in more detail later.

Further, the transparent pattern 203 of the transmittance control layer 200 may be formed in a semi-elliptical shape or a semi-circular shape having a curved surface and arranged to correspond to the light emitting area EA of each of the sub-pixels R-SP, G-SP, and B-SP. Due to the transparent pattern 203, the thickness (t 1 and t2 of fig. 3) of the gray pattern 205 of the transmittance controlled layer 200 may be formed differently for each region.

Accordingly, the organic light emitting display device 100 according to an embodiment of the present invention may control the transmittance of light (L1, L2, L3, and L4 of fig. 3) emitted from each of the sub-pixels R-SP, G-SP, and B-SP. Therefore, light incident at an angle less than or equal to a specific angle (L1 of fig. 3) is transmitted, and light incident at an angle greater than or equal to a specific angle (L2 and L4 of fig. 3) is prevented from being output to the outside. Accordingly, the up-down viewing angle and/or the left-right viewing angle of the organic light emitting diode display 100 may be controlled to be a narrow viewing angle.

A polarizing plate 120 for preventing a contrast reduction caused by external light may be positioned on the transmittance control layer 200. That is, in the organic light emitting display device 100, the polarizing plate 120 blocking external light incident from the outside may be positioned in a transmission direction of light emitted from the organic light emitting layer 113 in a driving mode for realizing an image, thereby improving contrast.

Fig. 3 is a schematic view showing an optical path of an organic light emitting display device according to an embodiment of the present invention, and fig. 4A and 4B are graphs showing light efficiency generated by recycling according to a viewing angle measurement.

Fig. 5A is a cross-sectional view illustrating a vertical viewing angle of one sub-pixel of an organic light emitting display device according to an embodiment of the present invention, and fig. 5B is a cross-sectional view illustrating a horizontal viewing angle of one sub-pixel of an organic light emitting display device according to an embodiment of the present invention.

As shown in fig. 3, the transmittance control layer 200 may include a black matrix 201 arranged to correspond to the non-light emitting region NEA of each of the sub-pixels R-SP, G-SP, and B-SP, and a transparent pattern 203 arranged to correspond to the light emitting region EA of each of the sub-pixels R-SP, G-SP, and B-SP, and may further include a gray pattern 205 covering the transparent pattern 203.

Here, the transparent pattern 203 may have a semi-elliptical or semi-circular lens shape including a curved surface. The diameter s1 of the transparent pattern 203 having the curved surface may be greater than the width w1 of the light emitting area EA of each of the sub-pixels R-SP, G-SP, or B-SP, and thus the transparent pattern 203 may be disposed over the entire light emitting area EA, and thus all light emitted from the light emitting area EA may be accommodated in the transparent pattern 203.

That is, the transparent pattern 203 may be arranged such that it has a size larger than the light emitting area EA of each of the sub-pixels R-SP, G-SP, and B-SP to cover at least a portion of all the light emitting area EA and the non-light emitting area NEA.

Here, the width w1 of the light emitting area EA may refer to the longest width within the light emitting area EA.

The transparent pattern 203 may be made of an adhesive resin (e.g., at least one resin selected from the group consisting of polyester-based, acrylic-based, polyurethane-based, melamine-based, polyvinyl alcohol-based, and oxazoline-based adhesive resins), preferably an acrylic-based adhesive resin.

The gray pattern 205 may be arranged to cover the transparent pattern 203 while filling the step formed by the lens-shaped transparent pattern 203. The gray pattern 205 may be formed of a mixture of the transparent pattern 203 and gray dye.

The transmittance of the transmittance controlled layer 200 may be adjusted according to the thicknesses t1 and t2 of the gray pattern 205.

That is, the gray pattern 205 can achieve various transmittance according to the thicknesses t1 and t2. As the thicknesses t1 and t2 of the gray pattern 205 increase, the transmittance decreases.

Here, since the transparent pattern 203 has a lens shape, the gray pattern 205 corresponding to the vertex of the lens shape of the transparent pattern 203 has a first thickness t1, and the gray pattern 205 corresponding to the side surface of the lens shape of the transparent pattern 203 has a second thickness t2 greater than the first thickness t 1.

The second thickness t2 of the gray pattern 205 may be substantially the maximum thickness on the lens-shaped side surface of the transparent pattern 203, and may be defined as the vertical thickness of the gray pattern 205 measured at the boundary between the light emitting area EA and the non-light emitting area NEA. Accordingly, the region corresponding to the first thickness t1 of the gray pattern 205 has an increased transmittance as compared to the region corresponding to the second thickness t2. The total transmittance of the gray pattern 205 of the transmittance control layer 200 may be designed to be a thickness per unit transmittance as shown in the following formula 1.

Formula 1: total transmittance = (-log transmittance) x thickness

That is, various transmittances can be achieved by adjusting thicknesses t1 and t2 of the gray pattern 205 of the transmittance control layer 200.

By the formula 1, the thicknesses t1 and t2 of the gray pattern 205 of the transmittance control layer 200 may be designed to have a desired transmittance at a specific region of each of the sub-pixels R-SP, G-SP, and B-SP.

Here, in the organic light emitting display device (100 of fig. 2) according to an embodiment of the present invention, it is preferable that the height h of the transparent pattern 203 is 5 μm to 8 μm and the thickness D of the gray pattern 205 is 6 μm to 15 μm. Preferably, the thickness D of the gray pattern 205 is increased by 20% to 30% compared to the height h of the transparent pattern 203.

Accordingly, in the organic light emitting display device (100 of fig. 2) according to an embodiment of the present invention, it may be designed that the gray pattern 205 of the transmittance control layer 200 having the first thickness t1 has a transmittance of 70% to 90% based on a 550nm wavelength band, and the gray pattern 205 having the second thickness t2 has a transmittance of 40% to 60% based on a 550nm wavelength band.

More preferably, the gray pattern 205 having the first thickness t1 may be designed to have a transmittance of 80% or more, and the gray pattern 205 having the second thickness t2 may be designed to have a transmittance of 50% or less.

Accordingly, when the light L1, L2, and L4 emitted from the organic light emitting layer (113 of fig. 2) of each of the sub-pixels R-SP, G-SP, and B-SP passes through the second electrode (115 of fig. 2) and is output to the outside, the first light L1 emitted vertically forward of the light L1, L2, and L4 is incident on the transparent pattern 203 of the transmittance control layer 200.

The first light L1 incident on the transparent pattern 203 passes through the transparent pattern 203 and then passes through the gray pattern 205 having the first thickness t 1. At this time, when 100% of the light is incident on the gray pattern 205, 70% to 90% of the first light L1 passes through the gray pattern 205 having the first thickness t1 and is output to the outside.

Among the lights L1, L2, and L4 emitted from the organic light emitting layer (113 of fig. 2), the second light L2 incident on the transmittance control layer 200 at an angle greater than or equal to a specific angle is blocked by the black matrix 201.

Here, the thickness d1 of the black matrix 201 may be designed according to the viewing angle. For example, the black matrix 201 preferably has a thickness d1 of several tens nanometers to several tens micrometers, but is not limited thereto. The black matrix 201 may have a thickness d1 capable of blocking light L2 traveling at an angle of ±45 degrees or more from the organic light emitting layer (113 of fig. 2) up and down and/or left and right with respect to the vertical plane of the organic light emitting display device (100 of fig. 2).

The black matrix 201 may be arranged to correspond to the non-light emitting region NEA of each of the sub-pixels R-SP, G-SP, and B-SP, and may be formed in a grid form. Accordingly, the organic light emitting display device (100 of fig. 2) can control the up-down viewing angle and the left-right viewing angle.

Therefore, the transmittance controlled layer 200 according to the embodiment of the invention can realize a narrow viewing angle.

In particular, the third light L3, which is a part of the second light L2, is reflected by the reflective layer 201a in the black matrix 201 and is incident into a part of the organic light emitting display device (100 of fig. 2) under the black matrix 201.

The third light L3 incident to the part in the organic light emitting display device (100 of fig. 2) is reflected back by the part in the organic light emitting display device (100 of fig. 2), and a part of the light L3-1 is directed toward the front surface and passes through the transparent pattern 203 of the transmittance control layer 200, and then is output to the outside, a part of the other light L3-2 is absorbed and removed by the black matrix 201, or a part of the other light L3-3 is reflected again by the reflective layer 201 a.

Therefore, by recycling the third light L3 traveling at an angle greater than or equal to a specific angle toward the transmittance control layer 200 through the reflective layer 201a, the light efficiency of the organic light emitting display device (100 of fig. 2) can be improved.

The black matrix 201 may be made of a dark pigment such as a black pigment or a gray pigment, a dark dye such as a black dye or a gray dye, carbon black, or a light blocking material such as a photoresist. A reflective layer 201a made of a light reflective material such as (A1) or silver (Ag) metal may be located at the lower layer of the black matrix 201.

The thickness d2 of the reflective layer 201a may be smaller than the thickness d1 of the black matrix 201. In the case where the thickness d2 of the reflective layer 201a may be equal to or greater than the thickness d1 of the black matrix 201, the second light L2 incident at an angle greater than or equal to a certain angle among the lights L1, L2, and L4 may be reflected on the side surface of the reflective layer 201a, and the path thereof may be changed toward an adjacent sub-pixel.

In this case, there is a problem in that light of an undesired color is emitted and color reproducibility is lowered.

Further, among the lights L1, L2, and L4 emitted from the organic light emitting layer (113 of fig. 2), the fourth light L4 incident on the transmittance control layer 200 at an angle greater than or equal to a certain angle passes through the transparent pattern 203 and then through the gray pattern 205 having the second thickness t2. At this time, 40% to 60% of the fourth light L4 is transmitted to the outside through the gray pattern 205 having the second thickness t2.

Here, the fourth light L4 may have a smaller angle than the second light L2 with respect to a vertical plane of the organic light emitting display device (100 of fig. 2). When the second light L2 travels up and down and/or left and right at an angle of ±45 degrees or more, the fourth light L4 may travel up and down and/or left and right at an angle of ±30 degrees or more with respect to the vertical plane.

At this time, the fourth light L4 passing through the gray pattern 205 having the second thickness t2 is output with a transmittance of 40% to 60%, and then passes through the polarization plate 120 on the transmittance controlled layer 200. Therefore, almost all of the fourth light L4 is eliminated while passing through the polarizing plate 120.

Fig. 4A is a graph showing light transmittance, in which the horizontal axis represents the wavelength of light and the vertical axis represents the transmittance. Sample a represents the transmission amount of light L4 passing through the gray pattern 205 of the transmittance control layer 200, and sample B represents the transmission amount after the light L4 passes through the gray pattern 205 and then through the polarizing plate 120.

Referring to fig. 4A, when the light L4 passes through the gray pattern 205 and then through the polarizing plate 120, the transmission amount of the light L4 passing through the gray pattern 205 and then through the polarizing plate 120 is significantly reduced as compared with the amount of the light L4 passing through the gray pattern 205 of the transmittance control layer 200.

Therefore, when the fourth light L4 passes through the gray pattern 205 of the second thickness t2 and then passes through the polarizing plate 120, the transmission amount is very low and almost all of the fourth light L4 is eliminated.

That is, in the organic light emitting display device (100 of fig. 2) according to an embodiment of the present invention, the viewing angle may be controlled mainly by the black matrix 201, and the viewing angle may be controlled secondarily by the gray pattern 205.

Accordingly, the organic light emitting display device (100 of fig. 2) according to the embodiment of the present invention has an up-down viewing angle of ±30 degrees and a left-right viewing angle according to the control of the viewing angle of the transmittance control layer 200, thereby realizing a narrow viewing angle.

Here, among the lights L1, L2, and L4 emitted from the organic light emitting layer (113 of fig. 2), the first light L1 vertically emitted toward the front surface also passes through the gray pattern 205 of the first thickness t1 on the transparent pattern 203, so that a part of the light is absorbed by the gray pattern 205. At this time, the light quantity of the first light L1 is compensated by the light quantity recovered by the reflective layer 201a of the black matrix 201.

Fig. 4B is a graph of light efficiency resulting from recycling as measured by viewing angle, where the horizontal axis represents viewing angle and the vertical axis represents light efficiency (i.e., intensity).

Before explanation, a is an experimental result of measuring the light efficiency of the organic light emitting layer (113 of fig. 2) when only the black matrix 201 is provided, and B is an experimental result of measuring the light efficiency of the organic light emitting layer (113 of fig. 2) when the black matrix 201 further includes the reflective layer 201a at the bottom thereof as in the embodiment of the present invention.

Referring to fig. 4B, it can be seen that the light efficiency at the center of B further increases. This is because the light efficiency of the organic light emitting display device (100 of fig. 2) is improved by causing the third light L3 traveling at a specific angle or more toward the transmittance control layer 200 to be recovered through the reflective layer 201 a.

As described above, in the organic light emitting display device (100 of fig. 2) according to the embodiment of the present invention, by further including the reflective layer 201a under the black matrix 201, the loss of the first light L1 vertically emitted toward the front surface among the light emitted from the organic light emitting layer (113 of fig. 2) is compensated, thereby further improving the light efficiency.

In summary, in the organic light emitting display device (100 of fig. 2) according to the embodiment of the present invention, the transmittance control layer 200 is formed on the outside of the substrate 101 through which the light L1, L2, and L4 is transmitted. Accordingly, the light L2 and L4 incident at an angle greater than this angle is blocked, and thus the viewing angle is limited.

That is, since the organic light emitting display device (100 of fig. 2) is used to display information desired by a user as an image, and it generally has a wide viewing angle, the user can view the image from various angles. However, when the viewing angle of each individual product to which the organic light emitting display device (100 of fig. 2) is applied is wide, product characteristics may be adversely affected, and in some cases, a user may require a narrow viewing angle.

As an example, in the case of an ATM of a bank, when a user inputs personal information, it is required to prevent others around from seeing the personal information. Therefore, more preferably, the viewing angle of the organic light emitting display device (100 of fig. 2) is narrow.

As another example, in the case of in-vehicle navigation, when the viewing angle of the organic light emitting display device (100 of fig. 2) is wide, the image displayed on the organic light emitting display device (100 of fig. 2) reduces the attention of the driver and interferes with driving. In addition, at night driving, an image displayed on the organic light emitting display device (100 of fig. 2) is reflected from the front windshield of the vehicle, which may adversely affect the safe driving of the driver.

As described above, although the organic light emitting display device (100 of fig. 2) is generally manufactured to have a wide viewing angle, a narrow viewing angle is required according to the product to which the display device is applied.

Therefore, it is necessary to manufacture the organic light emitting display device (100 of fig. 2) by adjusting the viewing angle to match the product to which the organic light emitting display device (100 of fig. 2) is applied, but if the organic light emitting display device (100 of fig. 2) is manufactured independently according to the product, productivity is lowered.

Accordingly, a method of narrowing the viewing angle of an organic light emitting diode display device (100 of fig. 2) manufactured to have a wide viewing angle is required. In the organic light emitting display device (100 of fig. 2) according to the embodiment of the present invention, the transmittance control layer 200 including the black matrix 201 and the gray pattern 205 is provided in the organic light emitting display device (100 of fig. 2) having a wide viewing angle, so that the wide viewing angle of the organic light emitting display device (100 of fig. 2) may be narrowed.

The viewing angle can be narrowed by further forming the transmittance control layer 200 provided with the black matrix 201 and the gray pattern 205 in the organic light emitting diode display device (100 of fig. 2).

Accordingly, the organic light emitting display device (100 of fig. 2) according to the embodiment of the present invention can protect privacy, and a separate film for limiting a viewing angle does not need to be added, so that a light and thin organic light emitting display device (100 of fig. 2) can also be realized.

In particular, since the transmittance control layer 200 can be formed at very low cost, the viewing angle can be limited at low cost, and the efficiency of the process can also be improved by simplifying the structure of the display device.

Meanwhile, when the organic light emitting display device (100 of fig. 2) including the transmittance control layer 200 according to the embodiment of the present invention is applied to the in-vehicle navigation, it is formed to have a narrow viewing angle in the up-down direction and a wide viewing angle in the left-right direction. Thereby, a wide viewing angle is achieved, so that an image displayed on the organic light emitting display device (100 of fig. 2) can also be provided to a passenger.

For this reason, in the organic light emitting display device (100 of fig. 2) according to an embodiment of the present invention, as shown in fig. 5A, the black matrix 201 may be arranged to correspond to the non-light emitting regions NEA of the sub-pixels R-SP, G-SP, and B-SP in the vertical viewing angle. Accordingly, the black matrix 201 can block light L2 traveling up and down at an angle of ±45 degrees or more from the organic light emitting layer (113 of fig. 2).

On the other hand, as shown in fig. 5B, the black matrix 201 may further include a pull-back region PB at a horizontal viewing angle.

The pull-back region PB may be defined as a region corresponding to a distance from an end of the bank 119 (which defines the light emitting region EA of each of the sub-pixels R-SP, G-SP, and B-SP) to an end of the black matrix 201 adjacent in the inner side direction of the bank 119. By pulling back the region PB, the black matrix 201 can be designed so as not to affect the maximum horizontal viewing angle of the user.

TABLE 1

Table 1 above shows experimental results of measuring the luminance reduction rate of the viewing angle according to the pull-back distance, and measuring the luminance reduction rate at the viewing angle of 45 degrees. As can be seen from table 1, the luminance reduction rate varies according to the pull-back region.

The pull-back region PB may be determined by a cell gap, which is defined as a distance from an upper (or top) surface of the organic light emitting layer (113 of fig. 2) to a lower (or bottom) surface of the black matrix 201. In general, in order not to affect the viewing angle of light L4 traveling at an angle of 30 degrees among light L1, L2, and L4 emitted from an organic light emitting layer (113 of fig. 2), a pull-back region PB of about 4 μm to 5 μm is required. Further, in order not to affect the viewing angle of the light L4 traveling at an angle of 45 degrees among the lights L1, L2, and L4 emitted from the organic light emitting layer (113 in fig. 2), the pullback region PB of about 6 μm to 7 μm is required.

Therefore, in the organic light emitting display device (100 of fig. 2) according to the embodiment of the present invention, in order to maintain a wide horizontal viewing angle while maintaining a narrow vertical viewing angle, the pull-back region PB is preferably designed to have a size of 4 μm to 9 μm (including a process error of 1 μm to 2 μm) in a horizontal direction with respect to the light emitting region EA.

Fig. 6A is a front view illustrating a shape of a transparent pattern according to an embodiment of the present invention, and fig. 6B is a view illustrating a structure of a unit pixel including three sub-pixels in a horizontal direction of a transparent lens in an organic light emitting display device according to an embodiment of the present invention.

As shown in fig. 6A, by including a pull-back region (PB of fig. 5B) in the black matrix 201 corresponding to the horizontal viewing angle, the transparent pattern 203 of the transmittance control layer 200 may be formed longer in the horizontal direction H than in the vertical direction V.

At this time, as shown in fig. 6B, the transparent pattern 203 arranged in the horizontal direction corresponding to the green sub-pixel G-SP may be formed to have a different shape of two curved surfaces based on vertices than the transparent pattern 203 arranged in the horizontal direction corresponding to the red sub-pixel R-SP and the blue sub-pixel B-SP. Accordingly, the second thickness t2 of the gray pattern 205 corresponding to the red and blue sub-pixels R-SP and B-SP may be different from the third thickness t3 corresponding to the green sub-pixel G-SP.

That is, the gray pattern 205 corresponding to the horizontal direction of the green sub-pixel G-SP may have a third thickness t3 thicker than the second thickness t2 of the gray pattern 205 corresponding to the horizontal direction of the red sub-pixel R-SP and the blue sub-pixel B-SP. Here, the gray pattern 205 having the second thickness t2 has a transmittance of 40% to 60%, so that the gray pattern 205 having the third thickness t3 may be designed to have a transmittance that is about 20% less than that of the gray pattern 205 having the second thickness t2. That is, it is preferable that the gray pattern 205 having the third thickness t3 has a transmittance of 20% to 40% based on a wavelength band of 550 nm.

Accordingly, among the light (L1, L2, and L4 of fig. 3) emitted from the organic light emitting layer (113 of fig. 2) of the green sub-pixel G-SP, the fourth green light L4G incident to the transmittance control layer 200 at an angle greater than or equal to a certain angle is transmitted through the gray pattern 205 having the third thickness t3. At this time, 20% to 40% of the fourth green light l4_g passes through the gray pattern 205 having the third thickness t3 and is output to the outside.

Accordingly, the transmittance of the fourth green light L4G is lower than the transmittance of the fourth red light L4R and the fourth blue light L4B incident on the transmittance control layer 200 at an angle greater than or equal to a specific angle among the light (L1, L2, and L4 of fig. 3) emitted from the organic light emitting layers (113 of fig. 2) of the red and blue sub-pixels R-SP and B-SP.

Fig. 7 is a graph showing light transmittance of each sub-pixel at a horizontal viewing angle. In fig. 7, the horizontal axis represents the wavelength of light, and the vertical axis represents the transmittance.

Sample C represents the transmittance of the fourth red light L4R and the fourth blue light L4B passing through the gray pattern 205 of the second thickness t2 of the transmittance control layer 200, and sample D represents the transmittance of the fourth green light l4_g passing through the gray pattern 205 of the third thickness t3 of the transmittance control layer 200.

Referring to fig. 7, it can be seen that the transmittance of the fourth green light L4G passing through the gray pattern 205 having the third thickness t3 of the transmittance control layer 200 in the sample D is lower than the transmittance of the fourth red light L4R and the fourth blue light l4_b passing through the gray pattern 205 having the second thickness t2 of the transmittance control layer 200 in the sample C.

Accordingly, it can be seen that the transmittance of the fourth green light L4G emitted from the organic light emitting layer (113 of fig. 2) of the green sub-pixel G-SP is lower than the transmittance of the fourth red light l4_r and the fourth blue light L4B emitted from the organic light emitting layer (113 of fig. 2) of the red sub-pixel R-SP and the blue sub-pixel B-SP.

Therefore, the phenomenon of greenish or yellowish can be prevented from occurring at the horizontal viewing angle.

That is, the red light l4_r and the blue light l4_b emitted from the red and blue sub-pixels R-SP and B-SP have a narrower horizontal viewing angle than the green light l4_g emitted from the green sub-pixel G-SP. Thus, a greenish or yellowish phenomenon (in which white turns to a greenish and yellow toward the extreme viewing angle) occurs. Such color differences may be perceived by a user, resulting in poor visual perception, and may be identified as display defects.

In this regard, referring to table 2 below, sample 1 represents a general organic light emitting display device, sample 2 represents an organic light emitting display device (100 of fig. 1) including gray patterns 205 having a second thickness t2 for each of sub-pixels R-SP, G-SP, and B-SP, and sample 3 represents an organic light emitting display device (100 of fig. 1) according to an embodiment of the present invention, including: the red and blue sub-pixels R-SP and B-SP including the gray pattern 205 having the second thickness t2 and the green sub-pixel G-SP including the gray pattern 205 having the third thickness t3 in the horizontal direction.

TABLE 2

As can be seen from examination of samples 1 and 2 of table 2, red light l4_r and blue light l4_b emitted from the red and blue sub-pixels R-SP and B-SP have brightness of 59% and 57% at 30-degree viewing angles, respectively, but green light l4_g emitted from the green sub-pixel G-SP has brightness of 67% at 30-degree viewing angles. Therefore, at a viewing angle of 30 degrees, the red light l4_r and the blue light l4_b have lower brightness than the green light l4_g.

On the other hand, in sample 3, green light l4_g had a brightness of 59%, which was reduced by about 5% compared to sample 2. Thus, the green light l4_g has similar brightness as the red light l4_r and the blue light l4_b.

That is, by forming the gray pattern 205 having the third thickness t3 at the horizontal viewing angle in the horizontal direction corresponding to the green sub-pixel G-SP, the brightness of the red light l4_r, the green light l4_g, and the blue light l4_b emitted from the red sub-pixel R-SP, the green sub-pixel G-SP, and the blue sub-pixel B-SP can be uniformized at the horizontal viewing angle.

Therefore, a phenomenon of greenish or yellowish (in which white turns to greenish and yellow toward extreme viewing angles) can be prevented from occurring. Accordingly, a color difference of white display is minimized, and thus an organic light emitting display device (100 of fig. 1) that prevents bad visual perception of a user can be realized.

As described above, in the organic light emitting display device (100 of fig. 1) according to the embodiment of the present invention, the transmittance control layer 200 including the black matrix 201, the lens-shaped transparent pattern 203, and the gray pattern 205 covering the transparent pattern 203 is formed on the outer side of the substrate (104 of fig. 6B) transmitting light. Accordingly, light incident at an angle greater than or equal to a specific angle (L2 of fig. 3) is blocked, so that a narrow viewing angle can be achieved.

Accordingly, the organic light emitting display device (100 of fig. 1) according to an embodiment of the present invention can protect privacy, and a separate film for limiting a viewing angle does not need to be added, so that a light and thin organic light emitting display device (100 of fig. 1) can be realized.

Further, since the transmittance control layer 200 can be formed at very low cost, the viewing angle can be limited at low cost, and the efficiency of the process can also be improved by simplifying the structure of the display device.

Further, by allowing light blocked by the black matrix 201 to be recovered, the light efficiency of the organic light emitting diode display device (100 of fig. 1) may be improved. Further, by further including a pull-back region (PB in fig. 5B) in the black matrix 201, a narrow viewing angle can be maintained under a vertical viewing angle while a wide horizontal viewing angle is maintained.

Further, by arranging the gray pattern 205 having the third thickness t3 to correspond to the green sub-pixel G-SP, it is possible to prevent the occurrence of the greenish or yellowish phenomenon at the horizontal viewing angle.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Accordingly, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

1. An organic light emitting display device comprising:

a substrate including first to third sub-pixels;

first to third light emitting diodes disposed on the substrate and respectively located in the first to third sub-pixels; and

a transmittance control layer toward which light emitted from the first to third light emitting diodes is transmitted, and which includes a lens-shaped transparent pattern and a gray pattern,

wherein the gray pattern is arranged as a transparent pattern covering the lens shape and has a different thickness according to the thickness of the transparent pattern.

2. The organic light-emitting display device according to claim 1, wherein the transparent pattern is arranged to correspond to a light-emitting region of each of the first to third sub-pixels, and

wherein the diameter of the transparent pattern is larger than the width of the light emitting region.

3. The organic light emitting display device according to claim 1, wherein a transmittance of the gray pattern corresponding to a first thickness of an apex of the transparent pattern is greater than a transmittance of the gray pattern corresponding to a second thickness of a side surface of the transparent pattern that is thicker than the first thickness.

4. The organic light-emitting display device according to claim 3, wherein the gray pattern having the first thickness has a transmittance of 70% to 90%, and

wherein the gray pattern having the second thickness has a transmittance of 40% to 60%.

5. The organic light emitting display device of claim 1, wherein a thickness of the gray pattern is 20% to 30% greater than a height of the transparent pattern.

6. The organic light-emitting display device according to claim 1, wherein a shape in a horizontal direction of the transparent pattern corresponding to a green sub-pixel of the first to third sub-pixels is different from a shape in a horizontal direction of the transparent pattern corresponding to red and blue sub-pixels of the first to third sub-pixels.

7. The organic light-emitting display device according to claim 6, wherein the gray pattern corresponding to the red and blue sub-pixels has a third thickness corresponding to a side surface of the transparent pattern in the horizontal direction, and

wherein the gray pattern arranged to correspond to the green sub-pixel has a fourth thickness greater than the third thickness corresponding to a side surface of the transparent pattern in the horizontal direction.

8. The organic light-emitting display device according to claim 7, wherein the gray pattern having the fourth thickness has a transmittance of 20% to 40%.

9. The organic light-emitting display device according to claim 1, wherein the transmittance control layer further comprises a black matrix corresponding to a non-light-emitting region surrounding an edge of the light-emitting region of each of the first to third sub-pixels, and

wherein a reflective layer is disposed under the black matrix.

10. The organic light-emitting display device according to claim 9, wherein the black matrix includes a pull-back region exposing a portion of the non-light-emitting region corresponding to a horizontal viewing angle.

11. The organic light-emitting display device according to claim 10, wherein the pull-back region has a width of 4 μm to 9 μm in a horizontal direction with respect to the light-emitting region.

12. The organic light-emitting display device according to claim 9, further comprising a polarizing plate located outside the transmittance-controlling layer.

13. The organic light-emitting display device according to claim 9, wherein a thickness of the reflective layer is smaller than a thickness of the black matrix.