KR20190070588A - Light emitting device and display device using the same - Google Patents

Abstract

According to an embodiment of the present invention, the present invention provides a light emitting element with increased light emitting efficiency, and a display device using the same. The light emitting element, which comprises an n-type semiconductor layer and a p-type semiconductor layer, comprises: an n-type electrode connected with the n-type semiconductor layer; and a p-type electrode connected with the p-type semiconductor layer. A surface corresponding to the p-type semiconductor layer on a plane is formed in a long trapezoid shape so as to increase light emitting efficiency.

Description

TECHNICAL FIELD [0001] The present invention relates to a light emitting device and a display device using the light emitting device.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device and a display device using the same. More particularly, the present invention relates to a light emitting device capable of improving reliability of electrodes by improving electrode connection efficiency and wire connection stability with respect to electrical connection between light emitting devices and wiring electrodes, Device.

Display devices are widely used as display screens of notebook computers, tablet computers, smart phones, portable display devices, and portable information devices in addition to display devices of televisions or monitors.

The display device can be divided into a reflection type display device and a light emission type display device. The reflection type display device is a display device in which natural light or light emitted from external light of the display device is reflected by the display device to display information, A display device includes a light emitting device or a light source built in a display device, and displays information using light emitted from a light emitting device or a light source.

The built-in light emitting device may use a light emitting device capable of emitting various wavelengths of light, a light emitting device emitting white or blue light, and a color filter capable of changing the wavelength of emitted light.

In order to realize an image as a display device, a plurality of light emitting elements are disposed on a substrate of a display device, and a driving element for supplying a driving signal or a driving current to control each light emitting element to emit light individually is called a light emitting element And a plurality of light emitting devices arranged on the substrate are analyzed in accordance with the arrangement of information to be displayed and displayed on the substrate.

To be more specific, in such a display device, a plurality of pixels are arranged, each pixel is driven by a thin film transistor (Thin Film Transistor) as a switching element which is a driving element and connected to the thin film transistor, The image is displayed.

Representative display devices using thin film transistors include liquid crystal display devices and organic light emitting display devices. Since the liquid crystal display device is not a self-emitting type, a backlight unit is required to emit light at a lower portion (rear surface) of the liquid crystal display device. With this additional backlight unit, the thickness of the liquid crystal display device is increased, and there are restrictions on implementing a display device in various forms of design such as a flexible or circular shape, and luminance and response speed may be lowered.

On the other hand, a display device having a self-luminous device can be realized to be thinner than a display device having a light source, and a flexible and foldable display device can be realized.

A display device having such a self-luminous device may include an organic light emitting display device including an organic material as a light emitting layer and a micro-LED display device using a micro-LED device as a light emitting device. In a display device such as an organic light emitting display device or a micro- The self-display device can be utilized as a thinner or more various display device since no separate light source is required.

However, since an organic light emitting display using an organic material does not require a separate light source, it is liable to generate defective pixels due to moisture and oxygen, so that various technical schemes are additionally required to minimize penetration of oxygen and moisture.

In recent years, research and development have been made on a display device using a micro-sized light emitting diode as a light emitting device, and such a light emitting display device has high image quality and high reliability Therefore, it is popular as a next generation display device.

An LED device is a semiconductor light emitting device that uses a property of emitting light when a current is flowed into the semiconductor, and is widely used for lighting, TV, and various display devices. The LED element is composed of an n-type semiconductor layer and a p-type semiconductor layer, and an active layer therebetween. Electrons are present in the n-type semiconductor layer portion and holes are present in the p-type semiconductor layer portion, and then the light is emitted from the active layer.

The LED device is composed of a compound semiconductor such as GaN, and can inject a high current due to the characteristics of an inorganic material, thereby realizing a high brightness and has high reliability due to low environmental impact such as heat, moisture and oxygen.

In addition, since the internal quantum efficiency of the LED device is higher than that of the organic light emitting display device at the level of 90%, it is possible to display a high-brightness image and realize a display device with low power consumption.

In addition, unlike an organic light emitting diode display, since an inorganic material is used, a separate sealing film or sealing substrate for minimizing penetration of oxygen and moisture at a level of insignificant influence of oxygen and moisture is not required, There is an advantage that the non-display area of the display device, which is a margin area that can be generated by disposition, can be minimized.

However, since a light emitting element such as an LED element may be formed using a separate semiconductor substrate and then transferred to a display device, a method of forming a light emitting element using a separate semiconductor substrate should be used , The manufacturing cost is increased.

However, in order to provide a display device having the advantages as described above, there is a technique of arranging a light emitting element at a correct position in a display device and a technique of minimizing a manufacturing cost while minimizing an error that may occur in the process of arranging the light emitting element need. Recently, a lot of research activities have been done on this.

As described above, there are several technical requirements for implementing a light emitting display device in which an LED element is used as a light emitting element of a unit pixel. First, an LED element is crystallized on a semiconductor wafer substrate such as sapphire or silicon (Si), and a plurality of crystallized LED chips are moved to a substrate having a driving element, A sophisticated transfer process for positioning the LED element is required.

The LED element can be formed using an inorganic material, but it needs to be formed by crystallization. In order to crystallize an inorganic material such as GaN, the inorganic material must crystallize on a substrate capable of inducing crystallization. The substrate on which the crystallization of the inorganic material can efficiently be induced is a semiconductor substrate, and the inorganic material must be crystallized on the semiconductor substrate as described above.

The process of crystallizing the LED element is also referred to as epitaxy, epitaxial growth, or an epitaxial process. In order to form the device structure of an LED device, a GaN-based compound semiconductor should be stacked on a substrate in the form of a pn junction diode, Lt; RTI ID = 0.0 > crystallinity. ≪ / RTI >

In this case, since the defects in the crystal act as a nonradiative center in the electron-hole recombination process, the crystallinity of the crystals forming each layer in a photon- Which has a decisive influence on the device efficiency.

The sapphire substrate described above is mainly used as a substrate mainly used at present, and recently, a research activity on a substrate based on GaN has actively been performed.

Because of the high price of a semiconductor substrate required for crystallizing an inorganic material such as GaN, which constitutes an LED light emitting element, on a semiconductor substrate, a large amount of light emitting pixels of a display device, rather than an LED used as a light source for simple illumination or backlighting There is a problem that the manufacturing cost is increased when the LED is used.

In addition, as described above, the LED element formed on the semiconductor substrate requires a step of transferring to the substrate constituting the display device. In this process, it is difficult to separate the LED element formed on the semiconductor substrate, There are also many difficulties and problems in transplanting the LED element to a desired spot.

A method of using a transfer substrate using a polymer material such as PDMS in transferring an LED element formed on a semiconductor substrate to a substrate on which a display device is implemented, a transfer method using an electromagnetic or electrostatic charge, And various methods of transcription can be used.

Such a transfer process is related to the productivity of the process of implementing the display device, and the method of transferring the LED devices one by one for mass production may be ineffective.

Accordingly, a plurality of LED elements are separated from a semiconductor substrate using a transfer substrate using a polymer material, and the substrate constituting the display device, particularly, the driving element arranged in the thin film transistor and the electrode pad connected to the power electrode, A transfer process or a method was required.

During the subsequent transfer process subsequent to the transferring process or after the transfer process, the LED device may be defective such that the LED device is inverted and transferred during movement or transfer according to the conditions of vibration or inferiority. There were many difficulties in recovering.

An example of a transfer process of an LED device taking an ordinary transfer process as an example will be described as follows. An LED element is formed on a semiconductor substrate and an electrode is formed on the semiconductor layer to complete an individual LED element. Thereafter, the semiconductor substrate and the PDMS substrate (hereinafter referred to as a transfer substrate) are brought into contact with each other to move the LED element to the transfer substrate. The transfer substrate must transfer the LED element from the semiconductor substrate to the transfer substrate in consideration of the distance of the pixel pitch of the LED element formed on the semiconductor substrate so that the LED element considering the pixel pitch of the display device A protrusion shape or the like is projected and disposed.

The LED element is separated from the semiconductor substrate by irradiating the laser element with the LED element through the back surface of the semiconductor substrate. At this time, when the LED element is separated from the semiconductor substrate during the laser irradiation, Due to the concentration of energy, physically rapid expansion can occur, which can cause shocks. (This is called primary transfer.)

Thereafter, the LED element transferred to the transfer substrate is transferred onto the substrate constituting the display device. The protective layer for insulating / protecting the thin film transistor is disposed on the substrate having the thin film transistor, and the adhesive layer is disposed on the protective layer .

When the transfer substrate is brought into contact with the substrate of the display device to apply pressure, the LED element transferred to the transfer substrate is transferred to the substrate side of the display device by the adhesive layer on the protective layer.

At this time, the adhesive force between the transfer substrate and the LED device is made smaller than the adhesive force between the substrate and the LED device constituting the display device, so that the LED device on the transfer substrate is transferred smoothly to the substrate of the display device. (This is called secondary transfer)

The substrate constituting the semiconductor substrate and the display device are basically different in size from each other, and the substrate constituting the display device is usually large. If the above-described primary and secondary transfer are repeatedly performed for a plurality of regions of the substrate of the display device due to such difference in area and size, the LED elements corresponding to the respective pixels constituting the display device can be transferred .

In the process of repeating the primary transfer and the secondary transfer, the LED element may be transferred to an unintended position, and various errors may occur depending on the transfer count or the process deviation of the transfer process.

The LED element formed on the semiconductor substrate may be an LED element of red, blue and green depending on the type thereof, or may be a white LED element. The number of primary and secondary transfers described above can be further increased in the method of implementing pixels of a display device by using an LED element emitting light of different wavelengths.

Even if the light emitting device is transferred to the substrate through a precise transfer process due to the increased number of primary and secondary transfers, all the primary and secondary transferred light emitting devices due to defects can be discarded, And the cost of the device is detected and corrected.

SUMMARY OF THE INVENTION The present invention provides a light emitting device having improved light efficiency in forming a light emitting device on a semiconductor substrate, and a display device using the same.

According to another embodiment of the present invention, there is provided a light emitting device comprising: a light emitting device formed on a semiconductor substrate; a light emitting device capable of forming a larger number of light emitting devices on the same area of the semiconductor substrate; And a display device using the same.

The solutions according to one embodiment of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

There is provided a light emitting device having increased luminous efficiency according to an embodiment of the present invention and a display device using the same. The light emitting element includes an n-type semiconductor and a p-type semiconductor, an n-type electrode is disposed on the n-type semiconductor, and a p-type electrode on the p-type semiconductor is disposed. The planar light emitting device may have a trapezoidal shape to increase the light emitting area of the p-type semiconductor layer having the p-type electrode, thereby providing a light emitting device with increased luminous efficiency and a display device using the same.

The light emitting efficiency of the display device can be improved by using the light emitting device having the structure capable of increasing the light emitting efficiency of the light emitting device according to the embodiment of the present invention. In addition, by using the light emitting element, there is an effect that consumption power of the display device can be minimized. On the other hand, the manufacturing cost can be minimized by increasing the number of light emitting devices that can be taken in the semiconductor device.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

The scope of the claims is not limited by the matters described in the contents of the invention, as the contents of the invention described in the problems, the solutions to the problems and the effects to be solved do not specify essential features of the claims.

1 is a schematic plan view of a light emitting display according to an embodiment of the present invention.
FIG. 2 is a schematic circuit diagram for explaining a configuration of a unit pixel according to the embodiment shown in FIG. 1. Referring to FIG.
3 is a schematic cross-sectional view for explaining the arrangement of a light emitting device according to an embodiment of the present invention.
4A and 4B are schematic plan views illustrating a light emitting device according to an embodiment of the present invention.
5 is a schematic view of a semiconductor substrate used for forming a light emitting device according to an embodiment of the present invention.
6 is a partial enlarged view of region A according to Fig.
7A to 7C are schematic plan views illustrating a light emitting device having increased light emitting efficiency compared to a conventional light emitting device.
8A and 8B are schematic plan views illustrating a light emitting device in which the number of chamfered portions of the light emitting device having similar luminous efficiency is increased.
9A and 9B are schematic views for explaining the process of transferring the light emitting device.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Where the terms "comprises", "having", "done", and the like are used in this specification, other portions may be added unless "only" is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if a temporal posterior relationship is described by 'after', 'after', 'after', 'before', etc., 'May not be contiguous unless it is used.

In the case of a description of the signal flow relationship, for example, even if 'signal is transmitted from node A to node B' And a case where a signal is transmitted to the B-node.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, and technically various interlocking and driving are possible, and that the embodiments may be practiced independently of each other, It is possible.

Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic plan view of a light emitting display according to an embodiment of the present invention, and FIG. 2 is a schematic circuit diagram for explaining the structure of a unit pixel according to the embodiment shown in FIG. 1 and 2, a light emitting display 100 according to an exemplary embodiment of the present invention includes a display region AA having a plurality of unit pixels UP and a non-display region IA And a substrate 110.

The unit pixel UP may be composed of a plurality of sub-pixels SP1, SP2 and SP3 on the front surface 110a of the substrate 110 and may be formed of red, blue, And may include subpixels (SP1, SP2, SP3) emitting light, but not limited thereto, and subpixels emitting light such as white.

The substrate 110 is a thin film transistor array substrate, and may be formed of glass or a plastic material, or may be a laminate of two or more substrates or a substrate divided into two or more layers. The non-display area IA may be defined as a region on the substrate 110 except for the display area AA, which may have a relatively narrow width, and may be defined as a bezel area.

 Each of the plurality of unit pixels UP is arranged in the display area AA. At this time, each of the plurality of unit pixels UP is arranged in the display area AA so as to have a predetermined first reference pixel pitch along the X-axis direction and have a predetermined second reference pixel pitch along the Y-axis direction. The first reference pixel pitch may be defined as the distance between the center portions of each adjacent unit pixel UP, and the second reference pixel pitch may be defined as the distance between each of the adjacent unit pixels UP in the reference direction similar to the first reference pixel pitch. Can be defined as the distance between the center and the center.

The distance between the subpixels SP1, SP2 and SP3 constituting the unit pixel UP is also defined as the first reference pixel pitch and the second reference pixel pitch similarly to the first reference pixel pitch and the second reference pixel pitch. .

The width of the non-display area IA may be smaller than the pixel pitch or the subpixel pitch described above, and may be equal to or smaller than the pixel pitch or the subpixel pitch. When the multi-screen display device is constituted by the light emitting display device 100 having the non-display area IA of the length of the non-display area IA, since the non-display area IA is smaller than the pixel pitch or the sub- The display device can be implemented.

In order to realize a multi-screen display device in which the bezel region is substantially absent or minimized as described above, the light emitting display device 100 has a first reference pixel pitch, a second reference pixel pitch, Although the first reference sub-pixel pitch and the second reference sub-pixel pitch may be kept constant, the display area AA may be defined as a plurality of zones and the pitch lengths may be different from each other within each zone, IA, the pixel pitch of the adjacent region may be made wider than the other region, so that the size of the bezel region can be made smaller than the pixel pitch relatively.

In this manner, the light emitting display device 100 having different pixel pitches may cause distortion of the image. Therefore, image processing is performed by sampling the image data in comparison with the adjacent region in consideration of the set pixel pitch, The bezel area can be minimized while minimizing distortion.

However, in order to minimize the non-display area IA, a pad area for connecting the power supply to the unit pixel UP in which the LED element 150 is provided and a circuit part for receiving and transmitting the data signal, a drive IC for driving, A minimum area is required.

The configuration and circuit structure of the sub-pixels SP1, SP2, and SP3 constituting the unit pixel UP of the light emitting display 100 will be described with reference to FIG. The pixel drive lines are provided on the front surface 110a of the substrate 110 and supply necessary signals to each of the plurality of sub-pixels SP1, SP2, and SP3. The pixel drive lines according to an embodiment of the present invention include a plurality of gate lines GL, a plurality of data lines DL, a plurality of driving power supply lines DPL, and a plurality of common power supply lines CPL.

Each of the plurality of gate lines GL is provided on a front surface 110a of the substrate 110 and extends in the first horizontal axis direction X of the substrate 110, (Y).

The plurality of data lines DL are provided on the front surface 110a of the substrate 110 so as to intersect the plurality of gate lines GL and extend in the second horizontal axis direction Y of the substrate 110 And are spaced apart from each other along the first horizontal axis direction X by a predetermined distance.

The plurality of driving power supply lines DPL are provided on the substrate 110 so as to be parallel to the plurality of data lines DL and may be formed together with each of the plurality of data lines DL. Each of the plurality of driving power supply lines DPL supplies a pixel driving power provided from the outside to the adjacent subpixels SP.

The plurality of common power supply lines CPL are provided on the substrate 110 so as to be parallel to each of the plurality of gate lines GL and may be formed together with each of the plurality of gate lines GL. Each of the plurality of common power supply lines CPL supplies a common power supplied from the outside to the adjacent sub-pixels SP1, SP2, and SP3.

Each of the plurality of subpixels SP1, SP2, and SP3 is provided in a subpixel region defined by a gate line GL and a data line DL. Each of the plurality of sub-pixels SP1, SP2, and SP3 may be defined as a minimum unit area in which actual light is emitted.

At least three sub-pixels SP1, SP2, and SP3 adjacent to each other may constitute one unit pixel UP for color display. For example, one unit pixel UP includes red sub-pixel SP1, green sub-pixel SP2 and blue sub-pixel SP3 adjacent to each other along the first horizontal axis direction X, For example, white subpixels.

Alternatively, each of the plurality of driving power supply lines DPL may be provided for each of the plurality of unit pixels UP. In this case, at least three sub-pixels SP1, SP2 and SP3 constituting each unit pixel UP share one driving power supply line DPL. Accordingly, it is possible to reduce the number of driving power supply lines for driving each of the sub-pixels SP1, SP2, and SP3, increase the aperture ratio of each unit pixel UP by the number of driving power supply lines that decrease, It is possible to reduce the size of the pixel UP.

Each of the plurality of sub-pixels SP1, SP2 and SP3 according to an embodiment of the present invention includes a pixel circuit PC and an LED element 150. [

The pixel circuit PC is provided in a circuit region defined in each subpixel SP and is connected to the adjacent gate line GL, data line DL and driving power supply line DPL. This pixel circuit PC is driven by the data signal from the data line DL in response to the scan pulse from the gate line GL based on the pixel drive power supplied from the drive power supply line DPL ) Of the current flowing through the capacitor. The pixel circuit PC according to an embodiment of the present invention includes a switching thin film transistor T1, a driving thin film transistor T2, and a capacitor Cst.

The switching thin film transistor T1 includes a gate electrode connected to the gate line GL, a first electrode connected to the data line DL and a second electrode connected to the gate electrode N1 of the driving thin film transistor T2. Here, the first and second electrodes of the switching TFT T1 may be a source electrode or a drain electrode depending on the current direction. The switching thin film transistor T1 is switched according to a scan pulse supplied to the gate line GL to supply a data signal to the data line DL to the driving thin film transistor T2.

The driving thin film transistor T2 is turned on by the voltage supplied from the switching thin film transistor T1 and / or the voltage of the capacitor Cst, thereby controlling the amount of current flowing from the driving power supply line DPL to the LED element 150 do. The driving thin film transistor T2 according to an embodiment of the present invention includes a gate electrode connected to the second electrode N1 of the switching thin film transistor T1, a drain electrode connected to the driving power supply line DPL, And a source electrode connected to the device 150. The driving thin film transistor T2 controls the data current flowing from the driving power line DPL to the LED element 150 based on the data signal supplied from the switching thin film transistor T1 to control the light emission of the LED element 150 do.

The capacitor Cst is provided in an overlapping region between the gate electrode N1 and the source electrode of the driving thin film transistor T2 and stores a voltage corresponding to the data signal supplied to the gate electrode of the driving thin film transistor T2, The driving TFT T2 is turned on.

Alternatively, the pixel circuit PC may further include at least one compensating thin film transistor for compensating for a change in threshold voltage of the driving thin film transistor T2, and further may include at least one auxiliary capacitor. The pixel circuit PC may be supplied with a compensating power such as an initializing voltage depending on the number of the thin film transistors and the auxiliary capacitors. Therefore, since the pixel circuit PC according to the embodiment of the present invention drives the LED device 150 through the current driving method like each sub pixel of the OLED display device, Circuit.

The LED element 150 is mounted on each of the plurality of sub-pixels SP1, SP2 and SP3. The LED element 150 is electrically connected to the pixel pixel circuit PC of the corresponding subpixel SP and the common power line CPL so that the pixel element circuit PC, that is, the driving thin film transistor T2, (CPL). The LED device 150 according to an embodiment of the present invention may be an optical device or a light emitting diode chip that emits one of red light, green light, blue light, and white light. Here, the light emitting diode chip may have a scale of 1 to 100 micrometers, but it may have a size smaller than the size of the remaining light emitting region excluding the circuit region occupied by the pixel pixel circuit (PC) .

3 is a schematic cross-sectional view illustrating an arrangement of a light emitting device according to an embodiment of the present invention. Hereinafter, description will be made with reference to FIG. 3, but with reference to the previous drawings.

Each of the sub-pixels SP1, SP2 and SP3 of the display device according to the embodiment of the present invention includes a protective layer 113, an LED element 150, planarization layers 115-1 and 115-2, a pixel electrode PE, And a common electrode CE.

Although the thickness of the substrate 110 is relatively thin in FIG. 3, the thickness of the substrate 110 may be substantially thicker than the total thickness of the layer structure provided on the substrate 110, Or may be a substrate composed of a plurality of layers or a plurality of substrates bonded together.

The pixel pixel circuit PC includes a switching thin film transistor T1, a driving thin film transistor T2, and a capacitor C. Since the pixel circuit PC is the same as that described above, a detailed description thereof will be omitted. Hereinafter, the structure of the driving thin film transistor T2 will be described by way of example.

The driving thin film transistor T2 includes a gate electrode GE, a semiconductor layer SCL, a source electrode SE, and a drain electrode DE.

The gate electrode GE is disposed on the substrate 110 together with the gate line GL. This gate electrode (GE) is covered by the gate insulating layer (112). The gate insulating layer 112 may be formed of a single layer or a plurality of layers made of an inorganic material, and may be formed of silicon oxide (SiOx), silicon nitride (SiNx), or the like.

The semiconductor layer SCL is provided in the form of a predetermined pattern (or island) on the gate insulating layer 112 so as to overlap with the gate electrode GE. The semiconductor layer SCL may be formed of a semiconductor material composed of any one of amorphous silicon, polycrystalline silicon, oxide, and organic material, but is not limited thereto.

The source electrode SE is disposed so as to overlap with one side of the semiconductor layer SCL. The source electrode SE is disposed together with the data line DL and the driving power supply line DPL.

The drain electrode DE is disposed so as to be spaced apart from the source electrode SE while overlapping with the other side of the semiconductor layer SCL. The drain electrode DE is disposed together with the source electrode SE and branches or protrudes from the adjacent driving power supply line DPL.

In addition, the switching thin film transistor T1 constituting the pixel pixel circuit PC is arranged in the same structure as the driving thin film transistor T2. At this time, the gate electrode of the switching thin film transistor T1 is branched or protruded from the gate line GL, the first electrode of the switching thin film transistor T1 is branched or protruded from the data line DL, and the switching thin film transistor T1 Is connected to the gate electrode GE of the driving thin film transistor T2 through a via hole provided in the gate insulating layer 112. [

The protective layer 113 is provided over the entire surface of the substrate 110 so as to cover the sub-pixel SP, that is, the pixel circuit PC. This protective layer 113 protects the pixel circuit PC and provides a flat surface. The protective layer 113 may be made of organic material such as benzocyclobutene or photo acryl, but it is preferably made of a photo-acrylic material for convenience of processing.

The LED element 150 according to an embodiment of the present invention may be disposed such that an adhesive member 114 is used on the protective layer 113. Alternatively, the inclined surface due to the concave portion in the protective layer 113 may be disposed in the concave portion provided on the protective layer 113, and the light emitted from the LED element 150 may be advanced in a specific direction to improve the luminous efficiency Can play a role.

The LED element 150 is electrically connected to the pixel pixel circuit PC and the common power supply line CPL to thereby apply a current to the pixel pixel circuit PC or the driving thin film transistor T2 from the common power supply line CPL And emits light. The LED device 150 according to an embodiment of the present invention includes a light emitting layer EL, a first electrode (or an anode terminal) E1, and a second electrode (or a cathode terminal) E2.

The LED element 150 emits light according to the recombination of electrons and holes according to the current flowing between the first electrode E1 and the second electrode E2.

The planarization layers 115-1 and 115-2 are disposed on the protective layer 113 so as to cover the LED element 150. [ That is, the planarization layers 115-1 and 115-2 are formed to have a thickness enough to cover both the front surface of the protective layer 113 and the LED element 150, .

The planarization layers 115-1 and 115-2 may be a single layer. As shown in the figure, the planarization layers 115-1 and 115-2 may include a first planarization layer 115-1 and a second planarization layer 115-2. 115-1, 115-2).

As such, the planarization layers 115-1 and 115-2 provide a flat surface on the protective layer 113. [ In addition, the planarization layers 115-1 and 115-2 serve to fix the position of the LED element 150. FIG.

The pixel electrode PE connects the first electrode E1 of the LED device 150 to the drain electrode DE of the driving thin film transistor T2 so that the pixel electrode PE is connected to the source electrode SE according to the configuration of the thin film transistor T2. A connection configuration is also possible. The pixel electrode PE may be defined as an anode electrode. The pixel electrode PE according to an embodiment of the present invention is provided on the entire surfaces of the planarization layers 115-1 and 115-2 overlapping the first electrode E1 of the LED element 150 and the driving thin film transistor T2 . The pixel electrode PE is connected to the drain electrode DE or the source electrode of the driving thin film transistor T2 through the first circuit contact hole CCH1 provided through the protective layer 113 and the planarization layers 115-1 and 115-2. And is electrically connected to the first electrode E1 of the LED device 150 through an electrode contact hole ECH provided in the planarization layers 115-1 and 115-2. The first electrode E1 of the LED element 150 is electrically connected to the drain electrode DE or the source electrode SE of the driving TFT T2 through the pixel electrode PE.

The drain electrode DE is connected to the pixel electrode PE in the connection relationship between the source electrode SE and the drain electrode DE but the pixel electrode PE and the source electrode SE may be connected to each other Which is an option of the skilled artisan.

The pixel electrode PE may be formed of a transparent conductive material when the display device is a top emission type and a light reflective conductive material when the display device is a bottom emission type. Here, the transparent conductive material may be indium tin oxide (ITO), indium zinc oxide (IZO), or the like, but is not limited thereto. The light reflecting conductive material may be Al, Ag, Au, Pt, Cu, or the like, but is not limited thereto. The pixel electrode PE made of a light-reflective conductive material may be a single layer including a light-reflective conductive material or a multilayer in which the single layer is stacked.

The common electrode CE electrically connects the second electrode E2 of the LED device 150 to the common power line CPL and may be defined as a cathode electrode. The common electrode CE is provided on the front surfaces of the planarization layers 115-1 and 115-2 which overlap the common electrode line CPL while overlapping the second electrode E2 of the LED element 150. [ Here, the common electrode CE may be made of the same material as the pixel electrode PE.

One side of the common electrode CE according to an embodiment of the present invention includes a gate insulating layer 112 overlapping a common power line CPL, a passivation layer 113 and planarization layers 115-1 and 115-2 And is electrically connected to the common power line CPL through the second circuit contact hole CCH2. The other side of the common electrode CE according to an embodiment of the present invention is connected to the second electrode E2 of the LED element 150 through an electrode contact hole ECH provided in the planarization layers 115-1 and 115-2 And is electrically connected to the second electrode E2 of the LED element 150. [ Accordingly, the second electrode E2 of the LED element 150 is electrically connected to the common power line CPL through the common electrode CE.

The pixel electrode PE and the common electrode CE according to the exemplary embodiment of the present invention may include planarization layers 115-1 and 115-2 including the first and second circuit contact holes CCH1 and CCH2 and the electrode contact hole ECH -2) and an electrode patterning process using a photolithography process and an etching process. Accordingly, since the pixel electrode PE connecting the LED element 150 to the pixel circuit PC and the common electrode CE can be disposed at the same time in one embodiment of the present invention, the electrode connecting process can be simplified , The process time for connecting the LED element 150 and the pixel circuit PC can be greatly shortened, thereby improving the productivity of the display device.

According to one embodiment of the present invention, the display apparatus further includes a transparent buffer layer 116. [

The transparent buffer layer 116 is provided on the substrate 110 so as to cover the entire planarization layers 115-1 and 115-2 provided with the pixel electrode PE and the common electrode CE, thereby forming the planarization layers 115-1 and 115-2 And protects the LED element 150 and the pixel pixel circuit PC from an external impact. Thus, the pixel electrode PE and the common electrode CE are provided between the planarization layers 115-1 and 115-2 and the transparent buffer layer 116, respectively. The transparent buffer layer 116 may be an optical clear adhesive (OCA) or an optical clear resin (OCR) according to an exemplary embodiment of the present invention.

The display device according to an embodiment of the present invention further includes a reflective layer 111 provided below the light emitting region of each subpixel SP.

The reflective layer 111 is provided on the substrate 110 so as to overlap the light emitting region including the LED element 150. The reflective layer 111 according to an exemplary embodiment of the present invention may be formed of the same material as the gate electrode GE of the driving TFT T2 and may be formed on the same layer as the gate electrode GE. The reflective layer 111 may be formed of the same material as any one of the electrodes constituting the driving TFT T2.

The reflection layer 111 reflects the light incident from the LED element 150 to the upper portion of the LED element 150. Accordingly, the display device according to an embodiment of the present invention has a top emission structure including the reflective layer 111. However, when the display device according to an embodiment of the present invention has a bottom emission structure, the reflective layer 111 may be omitted or disposed on the upper side of the LED device 150.

Alternatively, the reflective layer 111 may be formed of the same material as the source / drain electrode SE / DE of the driving TFT T2 and may be provided on the same layer as the source / drain electrode SE / DE.

The display device according to an embodiment of the present invention may be arranged such that the LED element 150 mounted on each subpixel SP corresponds to the upper portion of the corresponding reflective layer 111 by the adhesive member 114. [

The bonding member 114 primarily fixes the LED element 150 of each subpixel SP. The adhesive member 114 according to an embodiment of the present invention may contact the lower portion of the LED device 150 and minimize the positional displacement of the LED device 150 during the mounting process, The LED element 150 is smoothly separated from the LED element 150, and the defective process of the LED element 150 can be minimized.

The adhesive member 114 according to an embodiment of the present invention is dotted on each subpixel SP and spreads by the pressing force applied in the mounting process of the light emitting device so that the adhesive member 114 can be adhered to the lower portion of the LED device 150 have. Accordingly, the LED element 150 can be primarily fixed in position by the adhesive member 114. [ Therefore, according to the present embodiment, the mounting process of the light emitting device is performed by simply bonding the LED device 150 to the surface, so that the mounting process time of the light emitting device can be greatly shortened.

The adhesive member 114 is interposed between the protective layer 113 and the planarization layers 115-1 and 115-2 and interposed between the LED element 150 and the protective layer 113. [ A part of the adhesive member 114 coated on the entire surface of the protective layer 113 on which the contact holes are to be provided is formed to be in contact with the entire surface of the protective layer 113, Removed when the holes are arranged. Accordingly, in one embodiment of the present invention, the adhesive member 114 is coated on the entire front surface of the protective layer 113 to a predetermined thickness immediately before the mounting process of the light emitting device, thereby shortening the process time for disposing the adhesive member 114 .

The planarization layers 115-1 and 115-2 of this embodiment are provided so as to cover the adhesive member 114 because the adhesive member 114 is provided over the entire front surface of the protective layer 113. In this embodiment,

In another embodiment of the present invention, there is a recess for separately accommodating the LED element 150, and it can be positioned through the adhesive member 114 inside the recess. However, the recesses for accommodating the LED element 150 described above may be eliminated according to various process conditions for implementing the display device.

The mounting process of the light emitting device according to an embodiment of the present invention includes a process of mounting a red light emitting device on each of the red subpixels SP1, a process of mounting a green light emitting device on each of the green subpixels SP2, And the blue subpixels SP3, respectively, and mounting the white light emitting device on each of the white subpixels.

The mounting process of the light emitting device according to an exemplary embodiment of the present invention may include only a process of mounting a white light emitting device on each of the sub pixels. In this case, the substrate 110 includes a color filter layer overlapping each sub pixel. The color filter layer transmits only light having a wavelength of a hue corresponding to the sub-pixel among the white light.

The mounting process of the light emitting device according to an embodiment of the present invention may include only a process of mounting the light emitting device of the first color in each of the subpixels. In this case, the substrate 110 includes a wavelength conversion layer and a color filter layer overlapping each sub pixel. The wavelength conversion layer emits light of a second color based on a part of the light of the first color incident from the light emitting element. The color filter layer transmits only light having a wavelength of a hue corresponding to the sub-pixel among the white light resulting from the mixing of the light of the first color and the light of the second color. Here, the first hue may be blue and the second hue may be yellow. The wavelength conversion layer may include a phosphor or a quantum dot particle that emits light of a second color based on a part of light of the first color.

4A and 4B are schematic plan views illustrating a light emitting device according to an embodiment of the present invention. Referring to FIGS. 4A and 4B, a description will be made with reference to the previous drawings.

The LED element 150 according to an embodiment of the present invention includes a light emitting layer EL, a first electrode E1, a second electrode E2 and an insulating layer PAS, A first semiconductor layer 151, an active layer 152, and a second semiconductor layer 153. The LED element 150 emits light according to the recombination of electrons and holes according to the current flowing between the first electrode E1 and the second electrode E2.

The first semiconductor layer 151 may be a p-type semiconductor layer and the second semiconductor layer 153 may be an n-type semiconductor layer, but the first and second semiconductor layers 151 and 153 will be described for convenience. In addition, the first electrode E1 and the second electrode E2 may be referred to as a p-type electrode or an n-type electrode depending on an electrical connection relationship, that is, depending on a semiconductor layer that forms an electrical connection, We will explain it as two electrodes. Although the first semiconductor layer 151 and the second semiconductor layer 153 will be described as a p-type semiconductor layer and an n-type semiconductor layer in this specification, the first semiconductor layer 151 and the second semiconductor layer 153 An n-type semiconductor layer and a p-type semiconductor layer which are opposite to each other.

The first semiconductor layer 151 is provided on the active layer 152 to provide holes in the active layer 152. The first semiconductor layer 153 may be made of a p-GaN semiconductor material, and the p-GaN semiconductor material may be GaN, AlGaN, InGaN, AlInGaN, or the like. As the impurity used for doping the second semiconductor layer 153, Mg, Zn, Be, or the like may be used.

The second semiconductor layer 153 provides electrons to the active layer 152. The second semiconductor layer 153 according to an embodiment of the present invention may be formed of an n-GaN semiconductor material, and the n-GaN semiconductor material may be GaN, AlGaN, InGaN, or AlInGaN. Here, Si, Ge, Se, Te, C, or the like may be used as an impurity used for doping the second semiconductor layer 151.

The active layer 152 is provided on the second semiconductor layer 153. The active layer 152 has a multi quantum well (MQW) structure having a barrier layer having a higher bandgap than that of the well layer and the well layer. The active layer 152 according to an embodiment of the present invention may have a multiple quantum well structure such as InGaN / GaN.

The first electrode E1 is electrically connected to the first semiconductor layer 151 and is connected to the drain electrode DE or the source electrode SE of the driving transistor T2 as a driving thin film pixel, Is connected to a common power supply line (CPL).

The first electrode E1 may be a p-type electrode and the second electrode E2 may be an n-type electrode. In other words, the first electrode E1 and the second electrode E2 may be classified according to whether they supply electrons or holes, that is, whether they are electrically connected to the p-type semiconductor layer or connected to the n- E2).

Each of the first and second electrodes E1 and E2 according to an exemplary embodiment of the present invention includes a metal material such as Au, W, Pt, Si, Ir, Ag, Cu, Ni, Ti, Or more. Each of the first and second electrodes E1 and E2 may be made of a transparent conductive material. The transparent conductive material may be indium tin oxide (ITO) or indium zinc oxide (IZO) But is not limited thereto.

The insulating film PAS is disposed to cover the outside of the LED element 150 and is arranged to open at least a part of the second electrode E2 and is arranged so as to cover the active layer 152 and corresponds to the first electrode E1 (P-Open).

The splice film (PAS) may be disposed of a material such as SiNx or SiOx and is arranged to cover the active layer 152. The insulating film PAS is formed on the first electrode E1 and the second electrode E2 of the LED element 150 when the electrode is arranged such that the pixel electrode PE or the common electrode CE is electrically connected. Thereby preventing the electrical connection between the elements from occurring.

The LED element 150 may be a light emitting device having a bottom in a trapezoidal shape. The length of the first side of the first electrode E1 may be the longest side of the first semiconductor layer 151, It can be trapezoidal.

If the width of the p-type semiconductor layer is wider than that of the n-type semiconductor layer included in the LED element 150, the luminous efficiency can be increased. In other words, since the light efficiency can be increased by enlarging the area of the active layer 152 corresponding to the p-type semiconductor layer, the LED element 150 can be formed in a trapezoidal shape having a long side corresponding to the p- ), It is possible to provide the LED element 150 with increased luminous efficiency.

In addition, each of the second semiconductor layer 153, the active layer 152, and the first semiconductor layer 151 may be an LED element 150 formed by sequentially stacking on a semiconductor substrate. Here, the semiconductor substrate includes a semiconductor material such as a sapphire substrate or a silicon substrate. The semiconductor substrate is used as a growth substrate for growing the second semiconductor layer 153, the active layer 152, and the first semiconductor layer 151, and then the second semiconductor layer 153 is removed from the second semiconductor layer 153 Can be separated. Here, the substrate separation process may be a laser lift off or a chemical lift off. Accordingly, as the semiconductor substrate for growth is removed from the LED element 150, the LED element 150 can have a relatively thin thickness and can be accommodated in each sub-pixel SP.

FIG. 5 is a schematic view of a semiconductor substrate used for forming a light emitting device according to an embodiment of the present invention, and FIG. 6 is a partial enlarged view of an area A according to FIG.

As described above, the LED device 150 is formed on a semiconductor wafer and transferred to a display device to be driven as a light emitting device. In forming the LED device 150 on the semiconductor wafer, it is advantageous to form the LED device 150 in a straight alignment direction according to the pixel arrangement of the display device to be transferred.

In order to obtain the same number of LED elements 150 having the increased luminous efficiency on the same semiconductor substrate, the width of the side of the first electrode E1, which is related to the luminous efficiency of the LED element 150, It is possible to obtain the same number of improved LED elements 150 as the rectangular LED elements 150 by increasing the luminous efficiency by forming the LED elements 150 on the substrate. A detailed description thereof will be described with reference to the following drawings.

7A to 7C are schematic plan views illustrating a light emitting device having increased light emitting efficiency compared to a conventional light emitting device.

Referring to FIG. 7A, assuming that a total of four conventional elements (LEDs) can be obtained in a unit area of a semiconductor substrate defined by a first horizontal length W1 and a first vertical length H1, The LED device 150 is a trapezoidal type LED device 150 having an increased length of one side and the LED device 150 is formed in a unit area of a semiconductor substrate defined by a second lateral length W2 and a second longitudinal length H2, ) Will get a total of four.

At this time, when the first transverse length W1 and the second transverse length W2 are substantially equal and the first longitudinal length H1 and the second longitudinal length H2 are substantially equal, May be an LED element 150 having an increased area on the side of the first electrode E1 and having a higher luminous efficiency than a conventional element (LED).

Referring to FIG. 7C, the LED device 150 formed on the semiconductor substrate is transferred to the substrate of the display device through a transfer process. The transfer process uses a transfer substrate for transfer to perform a primary transfer process and a secondary transfer process . ≪ / RTI >

A plurality of LED elements 150 in one semiconductor substrate are divided and transferred in consideration of the interval of pixels without collective transfer, and the same transfer process is repeatedly performed. In the repeated transfer process, the process stability of the transfer process may be affected depending on the position where the LED device 150 is disposed on the semiconductor substrate.

The first electrode E1 of the neighboring LED device 150 faces the first electrode E1 of the neighboring LED device 150 as shown in the figure and the second electrode E2 Is disposed to face the second electrode E2 of the neighboring LED device 150, the stability of the transfer process of transferring the LED device 150 can be improved.

8A and 8B are schematic plan views illustrating a light emitting device in which the number of chamfered portions of the light emitting device having similar luminous efficiency is increased.

Referring to FIGS. 8A and 8B, when a total of four conventional elements (LEDs) can be obtained in a unit area of a semiconductor substrate defined by a first horizontal length W1 and a first vertical length H1, The area of the semiconductor substrate from which the four LED devices 150 having the vertical length h2 substantially equal to the vertical length h1 of the LEDs is equal to the second width W2 and the second height H2 In the case of the LED element 150 having an increased length of one side, the second longitudinal length H2 is smaller than the first longitudinal length H1. That is, the LED element 150 having substantially the same light emission luminance can be formed on a semiconductor substrate having a smaller area than the conventional element (LED), and the number of the LED elements 150 that can be obtained from the semiconductor substrate having the same area .

As described above, by increasing the number of the LED elements 150 that can be obtained on the semiconductor substrate having the same area, it is possible to reduce the manufacturing cost of the display device having the LED element 150.

9A and 9B are schematic views for explaining the process of transferring the light emitting device.

The LED element 250 is grown on a semiconductor substrate and patterned to complete the individual LED element 250. The LED element 250 on the semiconductor wafer is transferred to a donor primarily by bringing a semiconductor wafer and a donor into contact with each other, The LED element 250 may be transferred to a transfer substrate by irradiating the LED element 250 on the rear surface of the semiconductor wafer to separate the LED element 250 from the semiconductor wafer and adhere to the transfer substrate.

The transfer substrate 250 may be a substrate made of a highly adhesive material such as PDMS (Polydimethylsiloxane) as a polymer material, and a protrusion may be disposed at a distance corresponding to the distance between the pixels of the display device (pixel pitch) . The protrusion allows the LED element 250 to be stably transferred to the transfer substrate (donor), which can be removed depending on the material of the transfer substrate (donor) or the process conditions.

When the LED element 250 is transferred to the transfer substrate 250, an alignment step between the transfer substrate Donor and the semiconductor substrate is required. In the above-described configuration, The direction of the first electrode E1 and the direction of the second electrode E2 may be different from each other. Therefore, a method of rotating the semiconductor wafer and the donor 180 degrees may be used.

Alternatively, the display device may be configured by changing the electrode connection mode so that electrode connection is not a problem even if the LED devices 150 of the electrodes in different directions are arranged in the display device.

Thereafter, the LED element 250 transferred to the transfer substrate (Donor) is transferred to the light emitting element of the actual display device.

First, a step of aligning the transfer substrate (Donor) and the substrate 210 is performed and a step of implanting the LED element 250 into the substrate 210 is performed. When the substrate 210 and the transfer substrate are brought into contact with each other, the adhesive member 114 on the substrate 210 is bonded to the bottom surface of the LED element 250, as described with respect to the configuration shown in FIG. The substrate 210 and the LED element 250 have greater adhesive force than the transfer substrate by the adhesive member 114 and the LED element 250 is transferred to the substrate 210. [

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those embodiments and various changes and modifications may be made without departing from the scope of the present invention. . Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

100: Light emitting display
110: substrate
150: LED element
151: first semiconductor layer
152:
153: second semiconductor layer
154, 160: Structure
E1: first electrode
E2: Second electrode

Claims (10)

An n-type semiconductor layer In a light emitting device comprising a p-type semiconductor layer,
An n-type electrode on the n-type semiconductor layer; And
A p-type electrode on the p-type semiconductor layer; And
Wherein the light emitting element has a trapezoidal shape in a planar bottom surface. The method according to claim 1,
Wherein the light emitting device has a trapezoidal shape, and the side having the p-type semiconductor layer is a long side. The method according to claim 1,
And an insulating layer covering the light emitting element, wherein at least a part of the light emitting element having the n-type electrode is opened. The method of claim 3,
Wherein the insulating film has a contact hole for opening the p-type electrode. The method according to claim 1,
Wherein the n-type electrode and the p-type electrode are on the same plane. A light emitting element on the substrate and having an n-type electrode and a p-type electrode;
A pixel electrode disposed on the substrate and connected to the p-type electrode; And
A wiring electrode formed on the substrate and connected to the n-type electrode; And
Wherein the light emitting element has a trapezoidal shape in a planar bottom surface. The method according to claim 6,
Wherein the light emitting element further comprises a p-type semiconductor layer, and the p-type electrode is on the p-type semiconductor layer. The method according to claim 6,
Wherein the n-type electrode and the p-type electrode are on the same plane. The method according to claim 6,
Wherein the substrate includes at least one driving element and the pixel electrode is connected to the driving element. The method according to claim 6,
Wherein the light emitting device has different alignment directions of the p-type electrode and the n-type electrode of the neighboring light emitting device.

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