Full color pixel for micro LED display

Abstract

The subject matter of the present invention is a full color pixel for a micro LED display, wherein the full color pixel comprises at least one red light micro LED, at least one green light micro LED, and at least one blue light micro LED, which share a common n-electrode of the pixel.

Description

Full-color pixels for micro LED displays

[0001] The present invention relates to a full-color pixel for a micro LED display, and more particularly, to a full-color pixel designed in a specific form suitable for an ultra-high-resolution next-generation micro LED display.

[0002] Recent advancements in high-quality thin-film growth and device processing technologies have enabled the production of light-emitting devices of various sizes. In particular, micro LED display devices, which reproduce full-color images by directly controlling the three primary colors of light using micro LEDs measuring 100㎛ or less in blue (B), green (G), and red (R) light, are being actively developed.

[0003] Traditionally, micro LED-based display manufacturing technologies have been broadly categorized into two types depending on how RGB pixels are configured.

[0004] The first is a method of forming an RGB pixel by combining independent blue, green, and red micro LEDs, and the second is a method of forming an RGB pixel by combining a blue micro LED and a blue micro LED wrapped with green and red phosphors. Similarly to the latter, an RGB pixel can be formed by wrapping UV micro LEDs with blue, green, and red phosphors.

[0005] In the former case, productivity and yield are not high due to the difficulty of assembling individual red, green, and blue micro LEDs by transferring them to the display substrate to form RGB pixels. In addition, green and red micro LEDs have much lower luminous efficiency than blue micro LEDs, which reduces the overall efficiency of the RGB pixel. In addition, red micro LEDs are made of non-nitride semiconductors, which makes them thermally unstable compared to blue and green micro LEDs made of nitride semiconductors, and thus the emission wavelength can easily change depending on the ambient temperature, making it difficult to establish stability of the reproduced color.

[0006] The latter, based on a monolithic chip process, essentially encapsulates blue micro LED arrays at specific locations with green and red phosphors to form RGB pixels, offering superior productivity compared to the former. However, it's not easy to ensure uniform performance across the array's micro LEDs, and the phosphors have varying and low conversion efficiencies, making it technically far less efficient than the former.

[0007] Despite the pros and cons of the methods for forming full-color pixels described above, each micro LED light source used in these methods is manufactured with n / p electrodes built into them. Since the micro LEDs manufactured in this way must have an area occupied by n / p electrodes, it is not easy to manufacture micro LEDs of 5㎛ or less, which are necessary for implementing ultra-high resolution (over 5,000 PPI (pixel per inch)), when forming full-color pixels based on micro LEDs with independent n / p electrodes.

[0008] In addition, as the size of micro LEDs decreases and each light source LED is manufactured to have an independent electrode, it becomes increasingly difficult to transfer micro LEDs and connect the electrodes to a driver controller to form a display panel, making it difficult to form an ultra-high-resolution display with micro LEDs using existing methods.

[0009] The difficulties described above necessitate the development of new forms of micro LEDs to achieve the full-color pixels required for ultra-high-resolution displays.

[0010] The present invention, which aims to solve the problems of the prior art described above, provides a full-color pixel for a micro LED display capable of high integration of full-color pixels by having red light micro LEDs, green light micro LEDs, and blue light micro LEDs constituting a full-color pixel share a common n-electrode.

[0011] In order to achieve the above object, the present invention provides a full-color pixel for a micro LED display, characterized in that the full-color pixel for a micro LED display includes at least one red light micro LED, at least one green light micro LED, and at least one blue light micro LED, while sharing a common n-electrode.

[0012] In addition, it is preferable that the red light micro LED, the green light micro LED, and the blue light micro LED are each positioned at the same distance from the common n electrode.

[0013] In addition, it is preferable that the red light micro LED, the green light micro LED, and the blue light micro LED are arranged symmetrically with the common n electrode as the center.

[0014] In addition, it is preferable that the red light micro LED, the green light micro LED, and the blue light micro LED are formed in a triangular shape centered on the common n-electrode.

[0015] In addition, it is preferable that the red light micro LED, the green light micro LED, and the blue light micro LED are formed in a square shape centered on the common n-electrode.

[0016] In addition, it is preferable that the red light micro LED, the green light micro LED, and the blue light micro LED are formed in a pentagonal shape centered on the common n-electrode.

[0017] In addition, it is preferable that the red light micro LED, the green light micro LED, and the blue light micro LED are formed in a hexagonal shape centered on the common n-electrode.

[0018] In addition, the red light micro LED can be implemented by wrapping the blue light micro LED with a red light conversion phosphor, and the green light micro LED can be implemented by wrapping the blue light micro LED with a green light conversion phosphor.

[0019] Additionally, the size of the red light micro LED or the green light micro LED may be formed to be larger than the size of the blue light micro LED, or the size of the red light micro LED may be formed to be larger than the size of the green light micro LED.

[0020] Additionally, the number of the red light micro LED or the green light micro LED may be formed to be greater than the number of the blue light micro LED, or the number of the red light micro LED may be formed to be greater than the number of the green light micro LED.

[0021] In addition, the size of the pixel including the red light micro LED, the green light micro LED, and the blue light micro LED is 0.01 to 10,000 μm. 2 It is desirable that.

[0022] Since the present invention manufactures each of the red light micro LED, green light micro LED, and blue light micro LED constituting the full-color pixel to have a common n-electrode, the space required for configuring the full-color pixel can be reduced compared to a full-color pixel composed of micro LEDs each having a different n-electrode.

[0023] Therefore, it can integrate more than 5,000 full-color pixels per inch (5,000 PPI) required for ultra-high-resolution displays, so it can be usefully applied to ultra-high-resolution displays required for VR / AR / MR displays.

[0024] In addition, since it is easy to control the size and number of micro LEDs centered on the common n-electrode, the difference in luminous efficiency between each red light micro LED, green light micro LED, and blue light micro LED constituting a full-color pixel can be minimized.

[0025] In addition, since multiple micro LEDs can be implemented around a common n-electrode, the difference in resolution is minimal even if an individual micro LED is defective, so that repair costs due to pixel defects can be reduced.

[0026] In this way, if a next-generation display panel is configured with a full-color micro LED display module based on RGB pixels composed of a red light micro LED, a green light micro LED, and a blue light micro LED according to the present invention, a variety of rich colors can be reproduced.

[0027] Figure 1 - Schematic diagram showing a micro LED display module composed of full-color pixels and RGB pixels according to an embodiment of the present invention.

[0028] FIG. 2 - A schematic diagram showing a full-color pixel in which red light micro LEDs, green light micro LEDs, and blue light micro LEDs are arranged symmetrically in a triangular shape around a common n-electrode according to an embodiment of the present invention.

[0029] FIG. 3 is a schematic diagram showing a full-color pixel in which red light micro LEDs, green light micro LEDs, and blue light micro LEDs are arranged symmetrically in a square shape around a common n-electrode according to an embodiment of the present invention.

[0030] FIG. 4 - A schematic diagram showing a full-color pixel in which red light micro LEDs, green light micro LEDs, and blue light micro LEDs are arranged in a pentagonal symmetry with a common n-electrode as the center according to an embodiment of the present invention.

[0031] FIG. 5 - A schematic diagram showing a full-color pixel in which red light micro LEDs, green light micro LEDs, and blue light micro LEDs are arranged in a hexagonal shape with a common n-electrode as the center according to an embodiment of the present invention.

[0032] FIG. 6 - A diagram illustrating a blue micro LED array using full-color pixels arranged in a square shape centered on a common n-electrode according to an embodiment of the present invention.

[0033] The present invention can reduce the space required to configure full-color pixels by having red, green, and blue micro LEDs that constitute a full-color pixel share a common n-electrode. Accordingly, it is possible to integrate more than 5,000 full-color pixels per inch (5,000 PPI) required for ultra-high-resolution displays, making it suitable for ultra-high-resolution displays required for VR / AR / MR displays.

[0034] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. FIG. 1 is a schematic diagram showing a micro LED display module and RGB pixels made of full-color pixels according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing a full-color pixel in which a red micro LED, a green micro LED, and a blue micro LED are arranged symmetrically in a triangular shape with a common n electrode as the center according to an embodiment of the present invention, FIG. 3 is a schematic diagram showing a full-color pixel in which a red micro LED, a green micro LED, and a blue micro LED are arranged symmetrically in a square shape with a common n electrode as the center according to an embodiment of the present invention, FIG. 4 is a schematic diagram showing a full-color pixel in which a red micro LED, a green micro LED, and a blue micro LED are arranged symmetrically in a pentagonal shape with a common n electrode as the center according to an embodiment of the present invention, FIG. 5 is a schematic diagram showing a full-color pixel in which a red micro LED, a green micro LED, and a blue micro LED are arranged symmetrically in a hexagonal shape with a common n electrode as the center according to an embodiment of the present invention, and FIG. 6 is a schematic diagram showing a full-color pixel in which a red micro LED, a green micro LED, and a blue micro LED are arranged symmetrically in a square shape with a common n electrode as the center according to an embodiment of the present invention. This diagram illustrates a blue micro LED array using full-color pixels.

[0035] As illustrated, a full-color pixel (100) for a micro LED display according to an embodiment of the present invention is characterized by including at least one red light micro LED (30), at least one green light micro LED (20), and at least one blue light micro LED (10), while sharing a common n-electrode (22).

[0036] In addition, the present invention provides a micro LED display module (1000) including one or more full-color pixels (100), as illustrated in FIG. 1.

[0037] In general, in order for micro LED displays to be used in smart IT products including smartphones and virtual reality reproduction products called VR / AR / MR, the total size of full-color pixels and the distance between pixels must be 0.01 to 10,000㎛ each. 2 And it must be manufactured within the range of 0.1 to 100㎛. Therefore, the space that can form a full-color pixel is very narrow, making it very difficult to apply the conventional full-color pixel method that consists of independent single R / G / B LED chips with separate n-electrodes and p-electrodes.

[0038] In the present invention, a blue light micro LED array is manufactured in a special form to manufacture a full-color pixel (100), that is, a micro LED array is manufactured in such a way that the micro LEDs constituting the full-color pixel (100) share a common n-electrode (22), thereby solving the problems caused by the limitation of space.

[0039] To solve this, each of the R / G / B micro LEDs can share a common n-electrode (22), and the red LED, the green LED, and the blue LED can be positioned at equal distances with respect to the common n-electrode (22). In addition, the red LED, the green LED, and the blue LED can be arranged symmetrically with respect to the common n-electrode (22).

[0040] The full-color pixel (100) of the present invention is collectively referred to as an RGB pixel, each pixel emitting red light (R), green light (G), and blue light (B) based on the three (3) primary colors of light. In order to explain a preferred embodiment of the present invention, pixels required for full-color implementation may be referred to as RGB pixels, RRGB pixels, RGGB pixels, RRGGB pixels, RRRGB, RRRGGB, RRGGGB, and RRGGBB pixels, etc., based on the number of light sources.

[0041] As illustrated in Fig. 1, a red light source (red light micro LED (30)) and a green light source (green light micro LED (20)) required for full color reproduction can be configured by using some blue light micro LEDs (10) in a blue light micro LED array and blue light micro LEDs (10) combined with a green light phosphor or a red light phosphor. In this case, the conversion efficiency of the phosphors that convert blue light into green light or blue light into red light is different, so the difference in the luminous efficiency of the blue, green, and red light micro LEDs (30) is large.

[0042] In order to overcome this difference in luminous efficiency, it is preferable that the size of the red light micro LED (30) or the green light micro LED (20) be formed to be larger than the size of the blue light micro LED (10), and furthermore, the size of the red light micro LED (30) may be formed to be larger than the size of the green light micro LED (20).

[0043] In addition, as another embodiment to overcome this difference in luminous efficiency, it is preferable that the number of the red light micro LED (30) or the green light micro LED (20) be formed to be greater than the number of the blue light micro LED (10), and further, the number of the red light micro LED (30) may be formed to be greater than the number of the green light micro LED (20).

[0044] In addition, the shape and area size of the common n-electrode (22) can be adjusted and formed as needed for stable contact and operation with the n-electrode. That is, the area can be made wider than the size of the p-electrode (11), or it can be formed in a shape suitable for the common n-electrode (22).

[0045] As an embodiment of the present invention, FIG. 2 illustrates a full-color pixel (100) in which a red light micro LED (30), a green light micro LED (20), and a blue light micro LED (10) are arranged symmetrically in a triangular shape (Trigon-type RGB-Pixel). That is, the red light micro LED (30), the green light micro LED (20), and the blue light micro LED (10) constituting the pixel share the same n-electrode and are arranged symmetrically in a regular triangular shape at a constant interval from the common n-electrode (22).

[0046] In this way, if the red light micro LED (30), green light micro LED (20), and blue light micro LED (10) forming a full-color pixel (100) share the same n-electrode, the area required to form a full-color pixel (100) can be reduced, making it easy to manufacture high-density pixels and, furthermore, a micro LED display module (1000) formed of such pixels.

[0047] The full-color pixel (100) according to the embodiment of the present invention illustrated in FIG. 2 is an RGB pixel composed of three in total, one each of a red light micro LED (30), a green light micro LED (20), and a blue light micro LED (10) (R / G / B micro LED). In this case, the red light and green light are generated by converting blue light into green light or red light by wrapping the blue light micro LED (10) with a green light conversion phosphor or a red light conversion phosphor as described in FIG. 1.

[0048] The size of the full-color pixels (100) arranged in this way is 0.01 to 10,000㎛ in area. 2 , more preferably 1~100㎛ 2 And, the gap between the boundary of the common n-electrode (22) and the boundary of the micro LEDs may be 0.01 to 50 μm, more preferably 0.1 to 2 μm.

[0049] The above micro LEDs have a problem in that their luminous efficiency decreases rapidly as the chip size decreases. That is, the luminous efficiency of green light micro LEDs is lower than that of blue light, and red light micro LEDs are lower than that of green light when the chip size is 100㎛. 2 Below, the external quantum efficiency is very low. In particular, it is difficult for red-light micro LEDs to exceed 1%. To address this issue, in the embodiment of FIG. 2, the chip size of the red-light micro LED (30) can be manufactured to be larger than that of the blue-light micro LED (10) to prevent a decrease in external quantum efficiency.

[0050] Fig. 2(a) is a schematic diagram of a full-color pixel (100) in a triangular shape when viewed from above, and Fig. 2(b) is a diagram of a full-color pixel (100) in a triangular shape when viewed from the side to help understanding.

[0051] As another embodiment of the present invention, FIG. 3 illustrates a full-color pixel (100) in which a red light micro LED (30), a green light micro LED (20), and a blue light micro LED (10) are arranged symmetrically in a square shape. That is, the red light micro LED (30), the green light micro LED (20), and the blue light micro LED (10) constituting the pixel share the same n-electrode and are arranged symmetrically in a regular square shape at a constant interval from the common n-electrode (22).

[0052] The full-color pixel (100) according to the embodiment of the present invention illustrated in FIG. 3 is an RRGB pixel (Square-type RRGB-Pixel) composed of one (1) green light and blue light micro LED (10) and two (2) red light micro LEDs (30). In this case, the red light and green light are generated by converting the blue light of the blue LED using phosphors as described above.

[0053] The size of the full-color pixels (100) arranged in this way is 0.01 to 10,000㎛.2 , more preferably 1~100㎛ 2 And, the gap between the boundary of the n electrode (22) and the boundary of the micro LEDs may be 0.01 to 50 μm, more preferably 0.1 to 2 μm.

[0054] In the case of Fig. 3, the reason why the full color pixel (100) is configured as RRGB instead of RGB is that, as described above, the red light micro LED (30) has a chip size of 100㎛. 2 This is because the external quantum efficiency is less than 1%. By using two (2) red light micro LED (30) chips, as in the embodiment of Fig. 3, the insufficient red light can be supplemented. Similarly, the present invention can also be implemented by applying two (2) green light micro LEDs (20) instead of red light, if necessary.

[0055] Another embodiment of the present invention described in FIG. 4 for a similar purpose to the embodiment of FIG. 3 can be arranged in a regular pentagonal pattern with a constant angle centered on a common n-electrode (22). In this case, a full-color pixel (100) is an RRGGB pixel (Pentagon-type RRGGB-Pixel) composed of one (1) blue light micro LED (10), two (2) red light micro LEDs (30), and two (2) green light micro LEDs (20). In this case, red light and green light are generated by converting blue light using phosphors.

[0056] The size of the full-color pixels (100) arranged in this way is 0.01 to 10,000㎛. 2 , more preferably 1~100㎛ 2 And, the gap between the boundary of the n electrode (22) and the boundary of the micro LEDs may be 0.01 to 50 μm, more preferably 0.1 to 2 μm.

[0057] The embodiment of FIG. 4 may, in some cases, be an RRRGB pixel composed of three (3) red light micro LEDs (30) and one (1) each of green light and blue light micro LEDs (10). This allows for the implementation of multiple red light micro LEDs (30) centered around a common n-electrode (22), so that even if an individual red light micro LED (30) fails, the difference in resolution is minimal, thereby reducing the cost of repair due to pixel failure.

[0058] In another embodiment of the present invention, as described in FIG. 5, R / G / B light sources constituting a full-color pixel (100) may be arranged in a regular hexagonal pattern at regular intervals centered on a common n-electrode (22). In this case, the full-color pixel (100) is an RRGGBB pixel (Hexagon-type RGB-Pixel) composed of one (1) blue light micro LED (10), two (2) red light micro LEDs (30), and two (2) green light micro LEDs (20). The RRGGBB pixel can operate as a single pixel, but may also be regarded as two (2) independent full-color pixels (100).

[0059] Since it is possible to implement multiple micro LEDs centered on a common n-electrode (22), the difference in resolution is minimal even if an individual micro LED is defective, so that repair costs due to pixel defects can be reduced.

[0060] In the case of Fig. 5, red and green light are generated by converting blue light using fluorescent materials. The chip size of these micro LEDs is 0.01 to 10,000 ㎛ in area. 2 , more preferably 1~100㎛ 2 And, the gap between the boundary of the common n-electrode (22) and the boundary of the micro LEDs may be 0.01 to 50 μm, more preferably 0.1 to 2 μm.

[0061] The embodiment of the present invention described in FIG. 6 is an actual blue micro LED array using the square-shaped full-color pixel (100) described in FIG. 3. It demonstrates that a high-resolution full-color pixel (100) can be implemented by having four blue micro LEDs share a common n-electrode (22) located in the center.

[0062] The above blue light micro LED (10) may be made of a GaN-based nitride semiconductor, but in the case of a micro LED manufactured based on such a conventional GaN, the chip size is 100㎛ as described above. 2 Since the luminous efficiency tends to decrease rapidly when it becomes lower than this, the blue light micro LED (10) can be manufactured using a Hybrid LED composed of a GaN-based nitride semiconductor and a ZnO-based oxide semiconductor. The Hybrid LED can improve durability by increasing the internal luminous efficiency (IQE) and reducing the heat generation phenomenon due to surface leakage current. If such a Hybrid LED is applied as a micro LED required for the full-color pixel (100) of the present invention, problems related to the efficiency of conventional light-emitting devices can be solved.

[0063] In order to manufacture a full-color pixel (100) according to the present invention, it is manufactured integrally using a monolithic process method.

[0064] First, a blue light micro LED array is formed according to the arrangement of full-color pixels (100), and a phosphor capable of converting blue light into red light or green light is formed on some blue light micro LEDs (10) of the blue light micro LED array.

[0065] The above blue light micro LEDs (10) are independent light sources of at least three (3) or more, and are designed and manufactured in a monolithic manner so that the n-electrode (22) can be used in common. The above micro LEDs are arranged symmetrically and at equal distances from the common n-electrode (22). A micro LED display module (1000) can be manufactured in which a full-color pixel (100) composed of the blue light, green light, and red light micro LEDs (30) is configured as a basic unit.

[0066] The above blue light micro LED (10) may use a semiconductor material made of GaN or a hybrid semiconductor material made of ZnO and GaN.

[0067] A full-color pixel (100) composed of the above micro LEDs may be composed of at least one (1) blue light micro LED (10), at least one (1) green light micro LED (20), and at least one (1) red light micro LED (30).

[0068] Specifically, an example of configuring the above full-color pixel (100) may be described, wherein it may be composed of one (1) blue light micro LED (10), one (1) green light micro LED (20), and one (1) red light micro LED (30).

[0069] As another example of configuring the above full-color pixel (100), depending on the display usage environment, it may be configured with one (1) blue light micro LED (10), one (1) red light micro LED (30), and two (2) green light micro LEDs (20). Similarly, it may be configured with one (1) blue light micro LED (10), one (1) green light micro LED (20), and two (2) red light micro LEDs (30).

[0070] As another example of configuring the full-color pixel (100), the full-color pixel (100) composed of the micro LEDs may be composed of one (1) blue light micro LED (10), two (2) green light micro LEDs (20), and two (2) red light micro LEDs (30).

[0071] As another example of configuring the above full-color pixel (100), it may be composed of two (2) blue light micro LEDs (10), two (2) green light micro LEDs (20), and two (2) red light micro LEDs (30).

[0072] In this way, in order to increase the integration level, the R / G / B micro LEDs constituting the full-color pixel (100) are designed to use the same n-electrode (22) in common, and each light source constituting the full-color pixel (100) can be connected to a micro LED driving substrate (CMOS backplane) using flip-chip bonding technology.

[0073] In this way, the present invention can reduce the space required for configuring a full-color pixel by having the red light micro LED, the green light micro LED, and the blue light micro LED constituting the full-color pixel share a common n-electrode.

[0074] Therefore, it can integrate more than 5,000 full-color pixels per inch (5,000 PPI) required for ultra-high-resolution displays, so it can be usefully applied to ultra-high-resolution displays required for VR / AR / MR displays.

[0075] In addition, if a next-generation display panel is configured with a full-color micro LED display module based on RGB pixels composed of a red light micro LED, a green light micro LED, and a blue light micro LED according to the present invention, a variety of rich colors can be reproduced.

Claims

1. For full-color pixels for micro LED displays, While sharing a common n-electrode, comprising at least one red light micro LED, at least one green light micro LED, and at least one blue light micro LED; A full color pixel for a micro LED display, characterized in that the common n-electrode is one.

2. A full-color pixel for a micro LED display, characterized in that the red light micro LED, the green light micro LED, and the blue light micro LED are each positioned at the same distance from the common n-electrode in the first paragraph.

3. In the first paragraph, a full-color pixel for a micro LED display, characterized in that the red light micro LED, the green light micro LED, and the blue light micro LED are arranged symmetrically with the common n electrode as the center.

4. In the first paragraph, a full-color pixel for a micro LED display is formed by arranging the red light micro LED, the green light micro LED, and the blue light micro LED in a triangular shape centered on the common n-electrode.

5. In the first paragraph, a full-color pixel for a micro LED display is formed by arranging the red light micro LED, the green light micro LED, and the blue light micro LED in a square shape centered on the common n-electrode.

6. In the first paragraph, a full-color pixel for a micro LED display is formed by arranging the red light micro LED, the green light micro LED, and the blue light micro LED in a pentagonal shape centered on the common n-electrode.

7. In the first paragraph, a full-color pixel for a micro LED display is formed by arranging the red light micro LED, the green light micro LED, and the blue light micro LED in a hexagonal shape centered on the common n-electrode.

8. In the first paragraph, the red light micro LED, A full-color pixel for a micro LED display characterized in that the blue light micro LED is wrapped with a red light conversion phosphor.

9. In the first paragraph, the green light micro LED, A full-color pixel for a micro LED display characterized in that the blue light micro LED is wrapped with a green light conversion phosphor.

10. In the first paragraph, the size of the red light micro LED or the green light micro LED is A full-color pixel for a micro LED display, characterized in that it is formed larger than the size of the blue light micro LED.

11. In the 10th paragraph, the size of the red light micro LED is: A full-color pixel for a micro LED display, characterized in that it is formed larger than the size of the green light micro LED.

12. In the first paragraph, the number of the red light micro LED or the green light micro LED is A full-color pixel for a micro LED display, characterized in that it is formed in a number greater than the number of blue light micro LEDs.

13. In the 12th paragraph, the number of the red light micro LEDs is A full-color pixel for a micro LED display, characterized in that it is formed in a number greater than the number of green light micro LEDs.

14. In the first paragraph, the size of the full-color pixel including the red light micro LED, the green light micro LED, and the blue light micro LED is 0.01 to 10,000 μm. 2 Full color pixels for micro LED displays characterized by:

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