KR102317528B1 - Display apparatus and driving method thereof - Google Patents

Abstract

The present invention relates to a display device for compensating for a current deviation between a plurality of semiconductor light emitting devices (LEDs) applied to sub-pixels in a display panel driven by a digital pulse width modulation (PWM) method and a driving method thereof, A display device according to embodiments of the present specification includes: a plurality of semiconductor light emitting devices applied to sub-pixels included in pixels of a display panel; and a driving unit for driving the plurality of semiconductor light emitting devices based on a digital pulse width modulation (PWM) signal, and the driving unit may further include a compensating unit for compensating for a current deviation between the plurality of semiconductor light emitting devices.

Description

Display device and driving method thereof

The present invention relates to a display device and a method of driving the same

Recently, in the field of display technology, a display device having excellent characteristics such as a thin film type and a flexible type has been developed. In contrast, currently commercialized main displays are represented by LCD (Liguid Crystal Display) and AMOLED (Active Matrix Organic Light Emitting Diodes). However, in the case of LCD, there are problems in that the response time is not fast and it is difficult to implement flexibility, and in the case of AMOLED, the lifespan is short, the mass production yield is not good, and there are weaknesses in that the degree of flexibility is weak.

On the other hand, a light emitting diode (Light Emitting Diode: LED) is a well-known semiconductor light emitting device that converts electric current into light. It has been used as a light source for display images of electronic devices including communication devices. Accordingly, a method for solving the above problems by implementing a flexible display using the semiconductor light emitting device may be proposed.

In addition, in such a display device, thin film display technology development has become an important part as slimming is accelerated. In addition, the development of a touch screen that can be controlled using a finger or a pen on the display screen is also an important part of modern industry. On the other hand, in the general touch screen driving, the display driving time and the touch driving time are divided. During the display driving time, the touch circuit is not driven because the display panel noise is induced by the touch sensor and there is a high probability of failure in touch recognition. And during the touch operation time, the display is not driven for touch recognition. However, in the case of such time division, since the display does not emit light during the touch driving time, the light emission time within a unit frame is reduced and the maximum luminance of the display is reduced.

In addition, the display device according to the prior art requires a saw tooth wave signal by driving a digital panel based on PWM (pulse width modulation) of an analog method, and an analog comparator is installed in a micro-integration furnace that drives a pixel. must be included, so the size of the micro integrated circuit is increased.

In the display device according to the prior art, a digital to analog converter (DAC) that converts digital data into analog data by driving a digital panel based on an analog PWM (pulse width modulation) was required for the data driver. .

It is an object of the present invention to provide a display device for compensating for a current deviation between a plurality of semiconductor light emitting devices (LEDs) applied to sub-pixels in a display panel driven by a digital pulse width modulation (PWM) method, and a driving method thereof is to do

Another object of the present invention is to provide a display device that compensates for a current deviation between a reference current and a current flowing in a semiconductor light emitting device applied to a sub-pixel in a display panel driven by a digital PWM method, and a driving method thereof.

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

In order to achieve the above object, in the display device according to the embodiments of the present specification, a current deviation between a plurality of semiconductor light emitting devices (LEDs) applied to sub-pixels in a display panel is compensated for within a pixel of a display panel. a plurality of semiconductor light emitting devices applied to the included sub-pixels; and a driving unit for driving the plurality of semiconductor light emitting devices based on a digital pulse width modulation (PWM) signal, and the driving unit may further include a compensating unit for compensating for a current deviation between the plurality of semiconductor light emitting devices.

The driving unit may include: a switching unit connected to each of the plurality of semiconductor light emitting devices and switching the plurality of semiconductor light emitting devices according to the digital PWM signal; and a compensator connected between the switching unit and the ground, and compensating for a current deviation between the plurality of semiconductor light emitting devices. The driving unit may include a PWM generator generating the digital PWM signal.

The compensator may compensate for a difference between a current flowing through a first semiconductor light emitting device and a current flowing through a second semiconductor light emitting device among the plurality of semiconductor light emitting devices.

The display apparatus according to the embodiments of the present specification may further include an operational amplifier configured to apply a difference between a voltage applied to the plurality of semiconductor light emitting devices and a set voltage to the driving unit.

The compensator according to the embodiments of the present specification may include a first resistor connected in series to a first switching unit for switching a first semiconductor light emitting device among the plurality of semiconductor light emitting devices, the first switching unit and the first resistor a second resistor electrically connected between a point between the points and the input terminal of the operational amplifier; and a fourth resistor electrically connected between a point between the second switching unit and the third resistor and an input terminal of the operational amplifier.

The first resistor and the fourth resistor of the compensator according to the embodiments of the present specification have the same resistance value, and the second resistor and the third resistor are the current flowing through the first semiconductor light emitting device and the second semiconductor light emitting device It may have different resistance values to compensate for the deviation of the current flowing through the . In addition, the first resistor and the fourth resistor are fixed resistors having the same resistance value, the second resistor and the third resistor are variable resistors having different resistance values, and the driver is between the plurality of semiconductor light emitting devices. The resistance values of the variable resistors may be varied so that a current deviation does not occur.

The compensator may determine values of currents flowing through the plurality of semiconductor light emitting devices while compensating for the current deviation.

The driving unit may be one micro integrated circuit, and the one micro integrated circuit may drive a plurality of pixels, and each of the plurality of pixels may include a plurality of sub-pixels.

The display driving apparatus according to the embodiments of the present specification compensates for a current deviation between a current flowing in a semiconductor light emitting device applied to a sub-pixel in a display panel driven by a digital PWM method and a reference current,

A first current flowing through at least one of the plurality of semiconductor light emitting devices is detected in real time, and when the first current is different from a preset reference current, the preset reference current flows through the any one of the semiconductor light emitting devices. A current compensator for compensating for a difference between the first current and a preset reference current may be further included.

The details of other embodiments are included in the detailed description and drawings.

The LED display driving apparatus according to the embodiments of the present invention may improve the image quality of the display by compensating for a current deviation between a plurality of semiconductor light emitting devices applied to sub-pixels in a display panel.

The LED display driving apparatus according to the embodiments of the present invention may further improve the image quality of the display by compensating for a current deviation between the reference current and the current flowing in the semiconductor light emitting device applied to the sub-pixel in the display panel.

The driving device of the LED display according to the embodiments of the present invention drives a digital panel in a digital PWM method and uses serial digital data as it is, so that a semiconductor (Oxide and LTPS (Low temperature poly silicon, etc.) substrate backplane) There is no need to compensate the driving thin film transistor (TFT) required in the process, and the power supply voltage ELVDD for driving the pixel can be reduced.

The LED display driving apparatus according to the embodiments of the present invention drives a digital panel using a digital PWM method and uses serial digital data as it is, so that data can be input at a low voltage. For example, a silicon-based transistor having high mobility may be used, and power consumption when data is applied may be reduced.

In the LED display driving apparatus according to embodiments of the present invention, a digital to analog converter (DAC) for converting digital data into analog data in the data driving unit is unnecessary. For example, since the driving device of the LED display according to the embodiments of the present invention applies data in a digital manner, a digital to analog converter (DAC) is unnecessary in the data driving unit.

In the LED display driving apparatus according to the embodiments of the present invention, since a digital to analog converter (DAC) is not required in the data driving unit, the size of the data driving unit may be reduced.

The driving device of the LED display according to the embodiments of the present invention can secure a wide current range, and is applicable to a tiling display.

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

1 is a conceptual diagram illustrating an embodiment of a display device using a semiconductor light emitting device of the present invention.
FIG. 2 is a partially enlarged view of part A of FIG. 1 , and FIGS. 3A and 3B are cross-sectional views taken along lines BB and CC of FIG. 2 .
4 is a conceptual diagram illustrating the flip-chip type semiconductor light emitting device of FIG. 3A.
5A to 5C are conceptual views illustrating various forms of implementing colors in relation to a flip-chip type semiconductor light emitting device.
6 is a cross-sectional view illustrating a method of manufacturing a display device using a semiconductor light emitting device of the present invention.
7 is a perspective view illustrating another embodiment of a display device using the semiconductor light emitting device of the present invention.
FIG. 8 is a cross-sectional view taken along line CC of FIG. 7 ;
9 is a conceptual diagram illustrating the vertical semiconductor light emitting device of FIG. 8 .
10 is a block diagram illustrating a display device using a semiconductor light emitting diode (LED) according to an embodiment of the present invention.
11 is a block diagram illustrating a driving device of an LED display using a driving unit (eg, micro-IC) for digital pulse width modulation (PWM) driving according to an embodiment of the present invention.
12 is a block diagram illustrating a driving device of an LED display using a driving unit (eg, micro-IC) for digital pulse width modulation (PWM) driving according to another embodiment of the present invention.
13 is an exemplary view schematically illustrating a manufacturing method for a driving device of a light emitting diode (LED) display of FIG. 11 .
14 is an exemplary diagram schematically illustrating a manufacturing method for a driving device of a light emitting diode (LED) display of FIG. 12 .
15 is a block diagram illustrating a driving device of an LED display for compensating for current flowing in a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel according to another embodiment of the present invention.
16 is a block diagram illustrating a driving device of an LED display for compensating for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel according to another embodiment of the present invention.
17 is an exemplary diagram illustrating an operation of a compensator for compensating for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel according to another embodiment of the present invention.
18 to 20 are a plurality of light emitting devices according to a change in resistance value of a compensator for compensating for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel according to another embodiment of the present invention; Exemplary diagrams showing changes in voltage and current between (LEDs).

Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but the same or similar components are assigned the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted. The suffixes "module" and "part" for the components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have a meaning or role distinct from each other by themselves. In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, it should be noted that the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and should not be construed as limiting the technical spirit disclosed herein by the accompanying drawings.

It is also understood that when an element, such as a layer, region, or substrate, is referred to as being “on” another component, it may be directly on the other element or intervening elements in between. There will be.

The display device described in this specification includes a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, and a slate PC. , Tablet PC, Ultra Book, digital TV, desktop computer, and the like. However, it will be readily apparent to those skilled in the art that the configuration according to the embodiment described in this specification may be applied to a display capable device even in a new product form to be developed later.

1 is a conceptual diagram illustrating an embodiment of a display device using a semiconductor light emitting device of the present invention.

As illustrated, information processed by the control unit of the display apparatus 100 may be displayed using a flexible display.

The flexible display includes a display that can be bent, bent, twisted, folded, or rolled by an external force. For example, the flexible display may be a display manufactured on a thin and flexible substrate that can be bent, bent, folded, or rolled like paper while maintaining the display characteristics of a conventional flat panel display.

In a state in which the flexible display is not bent (eg, a state having an infinite radius of curvature, hereinafter referred to as a first state), the display area of the flexible display becomes a flat surface. In a state bent by an external force in the first state (eg, a state having a finite radius of curvature, hereinafter referred to as a second state), the display area may be a curved surface. As shown, the information displayed in the second state may be visual information output on the curved surface. Such visual information is implemented by independently controlling the light emission of sub-pixels arranged in a matrix form. The unit pixel means a minimum unit for realizing one color formed by a combination of R (Red), G (Green), and B (Blue).

The unit pixel of the flexible display may be implemented by a semiconductor light emitting device. In the present invention, a light emitting diode (LED) is exemplified as a type of a semiconductor light emitting device that converts current into light. The light emitting diode is formed to have a small size, so that it can serve as a unit pixel even in the second state.

Hereinafter, a flexible display implemented using the light emitting diode will be described in more detail with reference to the drawings.

FIG. 2 is a partially enlarged view of part A of FIG. 1 , FIGS. 3A to 3B are cross-sectional views taken along line BB of FIG. 2 , and FIG. 4 is a conceptual diagram illustrating the flip-chip type semiconductor light emitting device of FIG. 3 , FIG. 5A . 5C are conceptual views illustrating various forms of implementing colors in relation to a flip-chip type semiconductor light emitting device.

Referring to FIGS. 2, 3A and 3B , the display device 100 using a passive matrix (PM) type semiconductor light emitting device is exemplified as the display device 100 using a semiconductor light emitting device. However, the examples described below are also applicable to an active matrix (AM) type semiconductor light emitting device.

The display device 100 includes a substrate 110 , a first electrode 120 , a conductive adhesive layer 130 , a second electrode 140 , and a plurality of semiconductor light emitting devices 150 .

The substrate 110 may be a flexible substrate. For example, to implement a flexible display device, the substrate 110 may include glass or polyimide (PI). In addition, any material such as polyethylene naphthalate (PEN) or polyethylene terephthalate (PET) may be used as long as it has insulating properties and is flexible. Also, the substrate 110 may be made of either a transparent material or an opaque material.

The substrate 110 may be a wiring substrate on which the first electrode 120 is disposed, and thus the first electrode 120 may be located on the substrate 110 .

As shown, the insulating layer 160 may be disposed on the substrate 110 on which the first electrode 120 is positioned, and the auxiliary electrode 170 may be positioned on the insulating layer 160 . In this case, a state in which the insulating layer 160 is laminated on the substrate 110 may be a single wiring board. More specifically, the insulating layer 160 is made of an insulating and flexible material such as polyimide (PI, Polyimide), PET, or PEN, and is integrally formed with the substrate 110 to form a single substrate.

The auxiliary electrode 170 is an electrode that electrically connects the first electrode 120 and the semiconductor light emitting device 150 , is located on the insulating layer 160 , and is disposed to correspond to the position of the first electrode 120 . For example, the auxiliary electrode 170 may have a dot shape and may be electrically connected to the first electrode 120 by an electrode hole 171 penetrating the insulating layer 160 . The electrode hole 171 may be formed by filling the via hole with a conductive material.

Referring to the drawings, the conductive adhesive layer 130 is formed on one surface of the insulating layer 160 , but the present invention is not limited thereto. For example, a layer performing a specific function is formed between the insulating layer 160 and the conductive adhesive layer 130 , or the conductive adhesive layer 130 is disposed on the substrate 110 without the insulating layer 160 . is also possible In a structure in which the conductive adhesive layer 130 is disposed on the substrate 110 , the conductive adhesive layer 130 may serve as an insulating layer.

The conductive adhesive layer 130 may be a layer having adhesiveness and conductivity, and for this purpose, a material having conductivity and a material having adhesiveness may be mixed in the conductive adhesive layer 130 . In addition, the conductive adhesive layer 130 has ductility, thereby enabling a flexible function in the display device.

For this example, the conductive adhesive layer 130 may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, or the like. The conductive adhesive layer 130 may be configured as a layer that allows electrical interconnection in the Z direction penetrating through the thickness, but has electrical insulation in the horizontal X-Y direction. Accordingly, the conductive adhesive layer 130 may be referred to as a Z-axis conductive layer (however, hereinafter referred to as a 'conductive adhesive layer').

The anisotropic conductive film is a film in which an anisotropic conductive medium is mixed with an insulating base member, and when heat and pressure are applied, only a specific portion has conductivity by the anisotropic conductive medium. Hereinafter, it will be described that heat and pressure are applied to the anisotropic conductive film, but other methods are also possible in order for the anisotropic conductive film to have partial conductivity. In this method, for example, only one of the heat and pressure may be applied or UV curing may be performed.

In addition, the anisotropic conductive medium may be, for example, conductive balls or conductive particles. As shown, in this example, the anisotropic conductive film is a film in which conductive balls are mixed with an insulating base member, and when heat and pressure are applied, only a specific portion has conductivity by the conductive balls. The anisotropic conductive film may be in a state in which the core of the conductive material contains a plurality of particles covered by an insulating film made of a polymer material. . At this time, the shape of the core may be deformed to form a layer in contact with each other in the thickness direction of the film. As a more specific example, heat and pressure are applied to the anisotropic conductive film as a whole, and electrical connection in the Z-axis direction is partially formed by the height difference of the counterpart adhered by the anisotropic conductive film.

As another example, the anisotropic conductive film may be in a state in which an insulating core contains a plurality of particles coated with a conductive material. In this case, the conductive material is deformed (pressed) in the portion to which heat and pressure are applied, so that it has conductivity in the thickness direction of the film. As another example, a form in which the conductive material penetrates the insulating base member in the Z-axis direction to have conductivity in the thickness direction of the film is also possible. In this case, the conductive material may have a pointed end.

As shown, the anisotropic conductive film may be a fixed array anisotropic conductive film (ACF) in which conductive balls are inserted into one surface of the insulating base member. More specifically, the insulating base member is formed of a material having an adhesive property, and the conductive balls are intensively disposed on the bottom of the insulating base member, and when heat and pressure are applied from the base member, it is deformed together with the conductive balls. It has conductivity in the vertical direction.

However, the present invention is not necessarily limited thereto, and the anisotropic conductive film has a form in which conductive balls are randomly mixed in an insulating base member, or is composed of a plurality of layers and conductive balls are arranged on one layer (double- ACF) are all possible.

The anisotropic conductive paste is a combination of a paste and a conductive ball, and may be a paste in which a conductive ball is mixed with an insulating and adhesive base material. In addition, the solution containing conductive particles may be a solution containing conductive particles or nano particles.

Referring back to the drawing, the second electrode 140 is spaced apart from the auxiliary electrode 170 and is positioned on the insulating layer 160 . That is, the conductive adhesive layer 130 is disposed on the insulating layer 160 in which the auxiliary electrode 170 and the second electrode 140 are located.

After the conductive adhesive layer 130 is formed in the state where the auxiliary electrode 170 and the second electrode 140 are positioned on the insulating layer 160 , the semiconductor light emitting device 150 is connected in a flip-chip form by applying heat and pressure. In this case, the semiconductor light emitting device 150 is electrically connected to the first electrode 120 and the second electrode 140 .

Referring to FIG. 4 , the semiconductor light emitting device may be a flip chip type light emitting device.

For example, the semiconductor light emitting device includes a p-type electrode 156 , a p-type semiconductor layer 155 on which the p-type electrode 156 is formed, an active layer 154 formed on the p-type semiconductor layer 155 , an active layer ( It includes an n-type semiconductor layer 153 formed on the 154 , and an n-type electrode 152 spaced apart from the p-type electrode 156 in the horizontal direction on the n-type semiconductor layer 153 . In this case, the p-type electrode 156 may be electrically connected to the auxiliary electrode 170 and the conductive adhesive layer 130 , and the n-type electrode 152 may be electrically connected to the second electrode 140 .

Referring back to FIGS. 2 , 3A and 3B , the auxiliary electrode 170 is formed to be elongated in one direction, so that one auxiliary electrode may be electrically connected to the plurality of semiconductor light emitting devices 150 . For example, p-type electrodes of left and right semiconductor light emitting devices with respect to the auxiliary electrode may be electrically connected to one auxiliary electrode.

More specifically, the semiconductor light emitting device 150 is press-fitted into the conductive adhesive layer 130 by heat and pressure, and through this, between the p-type electrode 156 and the auxiliary electrode 170 of the semiconductor light emitting device 150 . Only a portion and a portion between the n-type electrode 152 and the second electrode 140 of the semiconductor light emitting device 150 have conductivity, and there is no press-fitting of the semiconductor light emitting device in the remaining portion, so that the semiconductor light emitting device does not have conductivity. As described above, the conductive adhesive layer 130 not only interconnects the semiconductor light emitting device 150 and the auxiliary electrode 170 and between the semiconductor light emitting device 150 and the second electrode 140 , but also forms an electrical connection.

In addition, the plurality of semiconductor light emitting devices 150 constitute a light emitting device array, and the phosphor layer 180 is formed on the light emitting device array.

The light emitting device array may include a plurality of semiconductor light emitting devices having different luminance values. Each of the semiconductor light emitting devices 150 is combined (or grouped) to constitute a unit pixel, and is electrically connected to the first electrode 120 . For example, there may be a plurality of first electrodes 120 , the semiconductor light emitting devices may be arranged in, for example, several columns, and the semiconductor light emitting devices in each column may be electrically connected to any one of the plurality of first electrodes.

In addition, since the semiconductor light emitting devices are connected in a flip chip form, semiconductor light emitting devices grown on a transparent dielectric substrate can be used. In addition, the semiconductor light emitting devices may be, for example, nitride semiconductor light emitting devices. Since the semiconductor light emitting device 150 has excellent luminance, individual unit pixels can be configured even with a small size.

As illustrated, a barrier rib 190 may be formed between the semiconductor light emitting devices 150 . In this case, the barrier rib 190 may serve to separate the semiconductor light emitting devices from each other, and may be integrally formed with the conductive adhesive layer 130 . For example, by inserting the semiconductor light emitting device 150 into the anisotropic conductive film, the base member of the anisotropic conductive film may form the partition wall.

In addition, when the base member of the anisotropic conductive film is black, the barrier rib 190 may have reflective properties and increase contrast even without a separate black insulator.

As another example, a reflective barrier rib may be separately provided as the barrier rib 190 . In this case, the barrier rib 190 may include a black or white insulator depending on the purpose of the display device. When the barrier ribs made of a white insulator are used, reflectivity may be increased, and when the barrier ribs made of a black insulator are used, it is possible to have reflective properties and increase contrast.

The phosphor layer 180 may be located on the outer surface of the semiconductor light emitting device 150 . For example, the semiconductor light emitting device 150 is a blue semiconductor light emitting device that emits blue (B) light, and the phosphor layer 180 functions to convert the blue (B) light into the color of a unit pixel. The phosphor layer 180 may be a red phosphor 181 or a green phosphor 182 constituting an individual pixel.

That is, a red phosphor 181 capable of converting blue light into red (R) light may be stacked on the blue semiconductor light emitting device 151 at a position forming a unit pixel of red color, and a position constituting a unit pixel of green color In , a green phosphor 182 capable of converting blue light into green (G) light may be stacked on the blue semiconductor light emitting device 151 . In addition, only the blue semiconductor light emitting device 151 may be used alone in the portion constituting the blue unit pixel. In this case, unit pixels of red (R), green (G), and blue (B) may form one pixel. More specifically, a phosphor of one color may be stacked along each line of the first electrode 120 . Accordingly, one line in the first electrode 120 may be an electrode for controlling one color. That is, red (R), green (G), and blue (B) may be sequentially disposed along the second electrode 140 , thereby realizing a unit pixel.

However, the present invention is not necessarily limited thereto, and instead of a phosphor, a unit pixel emitting red (R), green (G) and blue (B) is formed by combining the semiconductor light emitting device 150 and quantum dots (QD). can be implemented

In addition, a black matrix 191 may be disposed between each of the phosphor layers to improve contrast. That is, the black matrix 191 may improve contrast of light and dark.

However, the present invention is not necessarily limited thereto, and other structures for implementing blue, red, and green colors may be applied.

Referring to FIG. 5A , each semiconductor light emitting device 150 mainly uses gallium nitride (GaN), and indium (In) and/or aluminum (Al) are added together to emit a variety of light including blue light. It can be implemented as a device.

In this case, the semiconductor light emitting device 150 may be a red, green, and blue semiconductor light emitting device to form a sub-pixel, respectively. For example, red, green, and blue semiconductor light emitting devices R, G, and B are alternately disposed, and unit pixels of red, green, and blue are formed by the red, green, and blue semiconductor light emitting devices. The pixels form one pixel, through which a full-color display can be realized.

Referring to FIG. 5B , the semiconductor light emitting device may include a white light emitting device W in which a yellow phosphor layer is provided for each individual device. In this case, a red phosphor layer 181 , a green phosphor layer 182 , and a blue phosphor layer 183 may be provided on the white light emitting device W to form a unit pixel. In addition, a unit pixel may be formed on the white light emitting device W by using a color filter in which red, green, and blue are repeated.

Referring to FIG. 5C , a structure in which a red phosphor layer 181 , a green phosphor layer 182 , and a blue phosphor layer 183 are provided on the ultraviolet light emitting device UV is also possible. In this way, the semiconductor light emitting device can be used in the entire region not only for visible light but also for ultraviolet (UV) light, and can be extended to the form of a semiconductor light emitting device in which ultraviolet (UV) can be used as an excitation source of the upper phosphor. .

Referring back to this example, the semiconductor light emitting device 150 is positioned on the conductive adhesive layer 130 to constitute a unit pixel in the display device. Since the semiconductor light emitting device 150 has excellent luminance, individual unit pixels can be configured even with a small size. The size of the individual semiconductor light emitting device 150 may have a side length of 80 μm or less, and may be a rectangular or square device. In the case of a rectangle, the size may be 20X80㎛ or less.

In addition, even when a square semiconductor light emitting device 150 having a side length of 10 μm is used as a unit pixel, sufficient brightness to form a display device appears. Accordingly, for example, when the unit pixel is a rectangular pixel having one side of 600 μm and the other side of 300 μm, the distance between the semiconductor light emitting devices is relatively large. Accordingly, in this case, it is possible to implement a flexible display device having HD image quality.

The display device using the semiconductor light emitting device described above can be manufactured by a new type of manufacturing method. Hereinafter, the manufacturing method will be described with reference to FIG. 6 .

6 is a cross-sectional view illustrating a method of manufacturing a display device using a semiconductor light emitting device of the present invention.

Referring to this figure, first, the conductive adhesive layer 130 is formed on the insulating layer 160 on which the auxiliary electrode 170 and the second electrode 140 are positioned. An insulating layer 160 is laminated on the first substrate 110 to form one substrate (or wiring board), and the wiring substrate includes a first electrode 120 , an auxiliary electrode 170 , and a second electrode 140 . this is placed In this case, the first electrode 120 and the second electrode 140 may be disposed in a mutually orthogonal direction. In addition, in order to implement a flexible display device, the first substrate 110 and the insulating layer 160 may each include glass or polyimide (PI).

The conductive adhesive layer 130 may be implemented by, for example, an anisotropic conductive film, and for this purpose, the anisotropic conductive film may be applied to the substrate on which the insulating layer 160 is located.

Next, the second substrate 112 corresponding to the positions of the auxiliary electrode 170 and the second electrodes 140 and on which the plurality of semiconductor light emitting devices 150 constituting individual pixels are located is formed with the semiconductor light emitting device 150 . ) is disposed to face the auxiliary electrode 170 and the second electrode 140 .

In this case, the second substrate 112 is a growth substrate on which the semiconductor light emitting device 150 is grown, and may be a sapphire substrate or a silicon substrate.

When the semiconductor light emitting device is formed in a wafer unit, the semiconductor light emitting device can be effectively used in a display device by having an interval and a size that can form a display device.

Then, the wiring board and the second board 112 are thermocompression-bonded. For example, the wiring substrate and the second substrate 112 may be thermocompression-bonded by applying an ACF press head. The wiring substrate and the second substrate 112 are bonded by the thermocompression bonding. Due to the properties of the anisotropic conductive film having conductivity by thermocompression bonding, only the portion between the semiconductor light emitting device 150 and the auxiliary electrode 170 and the second electrode 140 has conductivity, and through this, the electrodes and the semiconductor light emitting. The device 150 may be electrically connected. At this time, the semiconductor light emitting device 150 is inserted into the anisotropic conductive film, and through this, a barrier rib may be formed between the semiconductor light emitting devices 150 .

Then, the second substrate 112 is removed. For example, the second substrate 112 may be removed using a laser lift-off (LLO) method or a chemical lift-off (CLO) method.

Finally, the second substrate 112 is removed to expose the semiconductor light emitting devices 150 to the outside. If necessary, a transparent insulating layer (not shown) may be formed by coating silicon oxide (SiOx) or the like on the wiring board to which the semiconductor light emitting device 150 is bonded.

In addition, the method may further include forming a phosphor layer on one surface of the semiconductor light emitting device 150 . For example, the semiconductor light emitting device 150 is a blue semiconductor light emitting device that emits blue (B) light, and a red phosphor or a green phosphor for converting the blue (B) light into the color of a unit pixel is the blue semiconductor light emitting device. A layer may be formed on one surface of the device.

The manufacturing method or structure of the display device using the semiconductor light emitting device described above may be modified in various forms. As an example, a vertical semiconductor light emitting device may also be applied to the display device described above. Hereinafter, a vertical structure will be described with reference to FIGS. 5 and 6 .

In addition, in the modification or embodiment described below, the same or similar reference numerals are assigned to the same or similar components as in the previous example, and the description is replaced with the first description.

7 is a perspective view showing another embodiment of a display device using a semiconductor light emitting device of the present invention, FIG. 8 is a cross-sectional view taken along line CC of FIG. 7, and FIG. 9 is a vertical type semiconductor light emitting device of FIG. It is a conceptual diagram.

Referring to the drawings, the display device may be a display device using a passive matrix (PM) type vertical semiconductor light emitting device.

The display device includes a substrate 210 , a first electrode 220 , a conductive adhesive layer 230 , a second electrode 240 , and a plurality of semiconductor light emitting devices 250 .

The substrate 210 is a wiring substrate on which the first electrode 220 is disposed, and may include polyimide (PI) to implement a flexible display device. In addition, any material that has insulating properties and is flexible may be used.

The first electrode 220 is positioned on the substrate 210 and may be formed as a bar-shaped electrode long in one direction. The first electrode 220 may serve as a data electrode.

The conductive adhesive layer 230 is formed on the substrate 210 on which the first electrode 220 is positioned. Like a display device to which a flip chip type light emitting element is applied, the conductive adhesive layer 230 is an anisotropic conductive film (ACF), an anisotropic conductive paste, and a solution containing conductive particles. ), and so on. However, in this embodiment as well, a case in which the conductive adhesive layer 230 is implemented by an anisotropic conductive film is exemplified.

After the anisotropic conductive film is positioned on the substrate 210 in a state where the first electrode 220 is positioned, when the semiconductor light emitting device 250 is connected by applying heat and pressure, the semiconductor light emitting device 250 becomes the first It is electrically connected to the electrode 220 . In this case, the semiconductor light emitting device 250 may be disposed on the first electrode 220 .

The electrical connection is created because, as described above, the anisotropic conductive film has conductivity in the thickness direction when heat and pressure are applied in part. Accordingly, the anisotropic conductive film is divided into a conductive portion 231 and a non-conductive portion 232 in the thickness direction.

In addition, since the anisotropic conductive film contains an adhesive component, the conductive adhesive layer 230 implements not only electrical connection but also mechanical bonding between the semiconductor light emitting device 250 and the first electrode 220 .

As described above, the semiconductor light emitting device 250 is positioned on the conductive adhesive layer 230 and constitutes individual pixels in the display device through this. Since the semiconductor light emitting device 250 has excellent luminance, individual unit pixels can be configured even with a small size. The size of the individual semiconductor light emitting device 250 may have a side length of 80 μm or less, and may be a rectangular or square device. In the case of a rectangle, the size may be 20X80㎛ or less.

The semiconductor light emitting device 250 may have a vertical structure.

A plurality of second electrodes 240 disposed in a direction crossing the longitudinal direction of the first electrode 220 and electrically connected to the vertical semiconductor light emitting device 250 are positioned between the vertical semiconductor light emitting devices.

Referring to FIG. 9 , the vertical semiconductor light emitting device includes a p-type electrode 256 , a p-type semiconductor layer 255 formed on the p-type electrode 256 , and an active layer 254 formed on the p-type semiconductor layer 255 . ), an n-type semiconductor layer 253 formed on the active layer 254 , and an n-type electrode 252 formed on the n-type semiconductor layer 253 . In this case, the lower p-type electrode 256 may be electrically connected to the first electrode 220 and the conductive adhesive layer 230 , and the upper n-type electrode 252 may be a second electrode 240 to be described later. ) can be electrically connected to. The vertical semiconductor light emitting device 250 has a great advantage in that it is possible to reduce the chip size because electrodes can be arranged up and down.

Referring back to FIG. 8 , a phosphor layer 280 may be formed on one surface of the semiconductor light emitting device 250 . For example, the semiconductor light emitting device 250 is a blue semiconductor light emitting device 251 that emits blue (B) light, and a phosphor layer 280 for converting the blue (B) light into the color of a unit pixel is provided. can be In this case, the phosphor layer 280 may be a red phosphor 281 and a green phosphor 282 constituting individual pixels.

That is, a red phosphor 281 capable of converting blue light into red (R) light may be stacked on the blue semiconductor light emitting device 251 at a position constituting a unit pixel of red color, and a position constituting a unit pixel of green color In , a green phosphor 282 capable of converting blue light into green (G) light may be stacked on the blue semiconductor light emitting device 251 . In addition, only the blue semiconductor light emitting device 251 may be used alone in the portion constituting the blue unit pixel. In this case, unit pixels of red (R), green (G), and blue (B) may form one pixel.

However, the present invention is not necessarily limited thereto, and as described above in a display device to which a flip chip type light emitting device is applied, other structures for realizing blue, red, and green may be applied.

Referring back to this embodiment, the second electrode 240 is positioned between the semiconductor light emitting devices 250 and is electrically connected to the semiconductor light emitting devices 250 . For example, the semiconductor light emitting devices 250 may be arranged in a plurality of columns, and the second electrode 240 may be located between the columns of the semiconductor light emitting devices 250 .

Since the distance between the semiconductor light emitting devices 250 constituting individual pixels is sufficiently large, the second electrode 240 may be positioned between the semiconductor light emitting devices 250 .

The second electrode 240 may be formed as a bar-shaped electrode long in one direction, and may be disposed in a direction perpendicular to the first electrode.

Also, the second electrode 240 and the semiconductor light emitting device 250 may be electrically connected to each other by a connection electrode protruding from the second electrode 240 . More specifically, the connection electrode may be an n-type electrode of the semiconductor light emitting device 250 . For example, the n-type electrode is formed as an ohmic electrode for ohmic contact, and the second electrode covers at least a portion of the ohmic electrode by printing or deposition. Through this, the second electrode 240 and the n-type electrode of the semiconductor light emitting device 250 may be electrically connected.

As illustrated, the second electrode 240 may be positioned on the conductive adhesive layer 230 . In some cases, a transparent insulating layer (not shown) including silicon oxide (SiOx) may be formed on the substrate 210 on which the semiconductor light emitting device 250 is formed. When the second electrode 240 is positioned after the transparent insulating layer is formed, the second electrode 240 is positioned on the transparent insulating layer. In addition, the second electrode 240 may be formed to be spaced apart from the conductive adhesive layer 230 or the transparent insulating layer.

If a transparent electrode such as indium tin oxide (ITO) is used to position the second electrode 240 on the semiconductor light emitting device 250 , the ITO material has a problem of poor adhesion to the n-type semiconductor layer. have. Accordingly, the present invention has the advantage of not using a transparent electrode such as ITO by locating the second electrode 240 between the semiconductor light emitting devices 250 . Therefore, it is possible to improve light extraction efficiency by using a conductive material having good adhesion to the n-type semiconductor layer as a horizontal electrode without being constrained by selection of a transparent material.

As illustrated, a barrier rib 290 may be positioned between the semiconductor light emitting devices 250 . That is, a barrier rib 290 may be disposed between the vertical semiconductor light emitting devices 250 to isolate the semiconductor light emitting devices 250 constituting individual pixels. In this case, the partition wall 290 may serve to separate individual unit pixels from each other, and may be integrally formed with the conductive adhesive layer 230 . For example, by inserting the semiconductor light emitting device 250 into the anisotropic conductive film, the base member of the anisotropic conductive film may form the partition wall.

In addition, when the base member of the anisotropic conductive film is black, the barrier rib 290 may have reflective properties and increase contrast even without a separate black insulator.

As another example, as the barrier rib 190 , a reflective barrier rib may be separately provided. The barrier rib 290 may include a black or white insulator depending on the purpose of the display device.

If the second electrode 240 is directly positioned on the conductive adhesive layer 230 between the semiconductor light emitting devices 250 , the barrier rib 290 is formed between the vertical semiconductor light emitting device 250 and the second electrode 240 . can be located between Accordingly, individual unit pixels can be configured even with a small size by using the semiconductor light emitting device 250 , and the distance between the semiconductor light emitting devices 250 is relatively large enough to connect the second electrode 240 to the semiconductor light emitting device 250 . ), and there is an effect of realizing a flexible display device having HD picture quality.

Also, as illustrated, a black matrix 291 may be disposed between each phosphor in order to improve a contrast ratio. That is, the black matrix 291 may improve contrast of light and dark.

As described above, the semiconductor light emitting device 250 is positioned on the conductive adhesive layer 230 and constitutes individual pixels in the display device through this. Since the semiconductor light emitting device 250 has excellent luminance, individual unit pixels can be configured even with a small size. Accordingly, a full-color display in which red (R), green (G), and blue (B) semiconductor light emitting devices constitute a unit pixel (or pixel) can be implemented by the semiconductor light emitting device.

Hereinafter, a display device using the semiconductor light emitting device (Light Emitting Diode or OLED) will be described with reference to FIG. 10 .

10 is a block diagram illustrating a display device using a semiconductor light emitting diode (LED) to which a display panel driving device according to an embodiment of the present invention is applied.

As shown in FIG. 10 , a display device using a semiconductor light emitting diode (LED) according to an embodiment of the present invention includes an image processing unit 201 , a timing control unit 202 , a data driving unit 203 , and a scan driving unit. 204 and a display panel 205 including a plurality of light emitting diodes (LEDs).

The image processing unit 201 receives a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a clock signal, and red, green, and blue signals RGB (hereinafter referred to as RGB) from the outside. The image processing unit 201 converts the RGB signals RGB into red, green, blue, and white signals RGBW (hereinafter referred to as RGBW) and outputs the converted RGB signals to the timing control unit 202 . The image processing unit 201 uses an RGB signal (RGB) included in one frame data supplied from the outside to vary a gamma voltage to realize a peak luminance according to an average image level. In addition, the image processing unit 201 variously processes frame data received from the outside, and a detailed description thereof will be omitted since it is a known technique.

The timing controller 202 receives a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a clock signal, and an RGBW signal RGBW from the image processing unit 201 .

The timing controller 202 controls operation timings of the data driver 203 and the scan driver 204 using timing signals such as a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a clock signal. Since the timing controller 202 can determine the frame period by counting the data enable signal of one horizontal period, the vertical synchronization signal and the horizontal synchronization signal supplied from the outside can be omitted. The control signals generated by the timing controller 202 include a gate timing control signal GDC for controlling the operation timing of the scan driver 204 and a data timing control signal DDC for controlling the operation timing of the data driver 203 . ) is included. The gate timing control signal GDC includes a gate start pulse, a gate shift clock, and a gate output enable signal. The data timing control signal DDC includes a source start pulse, a source sampling clock, and a source output enable signal.

The data driver 203 samples and latches the RGBW signal RGBW supplied from the timing controller 202 in response to the data timing control signal DDC received from the timing controller 202 to convert it into data of a parallel data system. . When converting the data of the parallel data system, the data driver 203 converts the RGBW signal RGBW into digital data into analog data according to the gamma voltage. In this case, the digital data to analog data is converted by a digital to analog converter (DAC) included in the data driver 203 . The data driver 203 supplies the converted image signal DATA through the data lines DL1 to DLn to the sub-pixels SPr, SPg, SPb, and SPw included in the display panel 205 .

The scan driver 204 enables transistors of the sub-pixels SPr, SPg, SPb, and SPw included in the display panel 205 to operate in response to the gate timing control signal GDC supplied from the timing controller 202 . The scan signal is sequentially generated while shifting the signal level with the swing width of the gate driving voltage. The scan driver 204 supplies the scan signal generated through the scan lines SL1 to SLm to the sub-pixels SPr, SPg, SPb, and SPw included in the display panel 205 .

The display panel 205 is formed of an organic light emitting display panel including sub-pixels SPr, SPg, SPb, and SPw arranged in a matrix form. The sub-pixels SPr, SPg, SPb, and SPw include a red sub-pixel SPr, a green sub-pixel SPg, a blue sub-pixel SPb, and a white sub-pixel SPw, which are one pixel (P). becomes this

In general, in order to drive an LED array as a display, a PM (Passive Matrix) method and an AM (Active Matrix) method are used. In the AM method, the light is maintained by memorizing the values of each pixel until the end of one frame, but in the PM method, the light is quickly turned on in line units and a visual afterimage effect (lasting about 1/10 second) is used to create one image. make it look like

Hereinafter, a driving device of an LED display using a driving unit (eg, micro-IC) for digital pulse width modulation (PWM) driving will be described with reference to FIG. 11 .

11 is a block diagram illustrating a driving device of an LED display using a driving unit (eg, micro-IC) for digital pulse width modulation (PWM) driving according to an embodiment of the present invention.

11, the driving device of the LED display using a driving unit (eg, micro-IC) for digital PWM (pulse width modulation) driving according to an embodiment of the present invention,

a plurality of light emitting elements (LEDs) 1104 applied to sub-pixels included in the display panel;

a data driver 1101 for generating serial digital data for driving a plurality of light emitting devices (LEDs) 1104;

a gate driver 1102 for generating a driving signal for driving a plurality of light emitting devices (LEDs) 1104 in response to the scan signal V _scan;

and a driving unit 1103 for driving a digital pulse width modulation (PWM) method and driving a plurality of light emitting devices (LEDs) 1104 based on the serial digital data and the driving signal.

The driver 1103 is a micro-IC, and includes a pulse width modulation (PWM) generator.

The data driver 1101 applies luminance information (serial digital data) of the plurality of light emitting elements (LEDs) 1104 to the plurality of light emitting elements (LEDs) 1104 through the driver 1103 .

The gate driver 1102 controls the current level of the micro-IC, selects an input order of data, and counts the emission times of the plurality of light emitting devices (LEDs) 1104 .

The data driver 1101 applies serial digital data as it is to the plurality of light emitting devices (LEDs) 1104 through the driver 1103 , thereby converting digital data into analog data (Digital to Analog Converter; DAC). ) is unnecessary.

A micro-IC (micro-IC) 1103 according to an embodiment of the present invention transmits data (Serial digital data) to a plurality of light emitting devices (LEDs) 1104 in a digital manner, and the digital data (digital data) data) as it is, since a digital comparator is used, the size of the micro-IC (micro-IC) 1103 can be made smaller than that of a circuit using analog data.

In addition, the data driver 1101 according to the embodiment of the present invention can transmit digital data to the plurality of light emitting devices (LEDs) 1104 as it is, so that the size of the integrated circuit of the data driver 1101 is a circuit using analog data. It can be made smaller.

The LED display driving device using a driving unit (eg, micro-IC) for digital pulse width modulation (PWM) driving according to an embodiment of the present invention does not use a thin film transistor (TFT). Power consumption is small due to the low power supply voltage to the pixel, and the degree of freedom of the metal process is high, making it possible to make small parasitic resistance (R) and capacitance (C) (beneficial to securing data transmission speed and power consumption) may decrease).

Hereinafter, the present invention will be described with reference to FIG. 11 a driving device for an LED display using a driving unit (eg, micro-IC) for digital PWM (pulse width modulation) driving.

12 is a block diagram illustrating a driving device of an LED display using a driving unit (eg, micro-IC) for digital pulse width modulation (PWM) driving according to another embodiment of the present invention, and one driving unit (eg, For example, it is a block diagram showing a driving device of an LED display that drives a plurality of pixels (one pixel includes a plurality of sub-pixels) using a micro-IC.

As shown in FIG. 12, the driving device of the LED display using a driving unit (eg, micro-IC) for digital PWM (pulse width modulation) driving according to another embodiment of the present invention is,

a plurality of light emitting elements (LEDs) 1201 to 1204 applied to a plurality of pixels (eg, 2 to 4 pixels) included in the display panel;

a data driver 1101 for generating serial digital data for driving a plurality of light emitting devices (LEDs) 1201 to 1204;

a gate driver 1102 for generating a driving signal for driving the plurality of light emitting devices (LEDs) 1201 to 1204 in response to the scan signal V _scan;

One driving a plurality of light emitting devices (LEDs) 1201 to 1204 applied to a plurality of pixels based on the digital pulse width modulation (PWM) method and the serial digital data and the driving signal includes a driving unit 1103 of

The driver 1103 is a micro-IC, and includes a pulse width modulation (PWM) generator.

One driver 1103 may drive sub-pixels (a plurality of light-emitting devices) applied to one pixel or drive sub-pixels (a plurality of light-emitting devices) applied to a plurality of pixels.

13 is an exemplary view schematically illustrating a manufacturing method for the driving device of the LED (Light Emitting Diode) display of FIG. 11 .

13, the driving unit 1103 for driving the plurality of light emitting devices (LEDs) 1104 is electrically connected to the pad (LED pad) 1104a, and the pad (LED pad) 1104a has the A plurality of light emitting elements (LEDs) 1104 are electrically connected.

The driver 1103 may be connected to the pad (LED pad) 1104a through a metal wire (Metal 2) such as gold or silver, and a driving voltage (eg, a driving voltage for driving the plurality of light emitting devices (LEDs) 1104 ) For example, VDD, V _G , V _S , etc.) may be connected to the driving unit 1103 through a metal wire (Metal 1) such as copper or aluminum.

The driver 1103 may include a red sub-pixel SPr, a green sub-pixel SPg, a blue sub-pixel SPb, and a white sub-pixel SPw corresponding to one pixel or a red sub-pixel SPr corresponding to one pixel. ), the green sub-pixel SPg, and the blue sub-pixel SPb may be connected to a semiconductor light emitting device respectively applied thereto.

14 is an exemplary diagram schematically illustrating a manufacturing method for a driving device of a light emitting diode (LED) display of FIG. 12 .

As shown in FIG. 14 , one driver 1103 for driving a plurality of light emitting elements (LEDs) 1104 includes a plurality of pixels (eg, four pixels) included in the display panel. electrically connected to pads (LED pads) 1201a to 1204a that are electrically connected to light emitting elements (LEDs) 1201 to 1204 . One driving unit 1103 may be connected to the pads (LED pads) 1201a to 1204a through a metal wire such as gold or silver, and a driving voltage for driving the plurality of light emitting devices (LEDs) 1201 to 1204 . (eg, VDD, V _G , V _S , etc.) may be connected to one driving unit 1103 through a metal wire such as copper or aluminum. The driver 1103 may include a red sub-pixel SPr, a green sub-pixel SPg, a blue sub-pixel SPb, and a white sub-pixel SPw corresponding to one pixel or a red sub-pixel SPr corresponding to one pixel. ), the green sub-pixel SPg, and the blue sub-pixel SPb may be connected to a semiconductor light emitting device respectively applied thereto.

Hereinafter, an LED display driving device for compensating for current flowing in a plurality of light emitting devices (LEDs) applied to sub-pixels included in the display panel will be described with reference to FIG. 15 .

15 is a block diagram illustrating a driving device of an LED display for compensating for current flowing in a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel according to another embodiment of the present invention.

As shown in Figure 15, the driving device of the LED display according to another embodiment of the present invention,

a plurality of light emitting elements (LEDs) 1104 applied to sub-pixels included in the display panel;

a data driver 1101 for generating serial digital data for driving a plurality of light emitting devices (LEDs) 1104;

a gate driver 1102 for generating a driving signal for driving a plurality of light emitting devices (LEDs) 1104 in response to the scan signal V _scan;

a driving unit 1103 for driving in a digital pulse width modulation (PWM) method and driving the plurality of semiconductor light emitting devices based on the serial digital data and the driving signal;

A first current flowing through at least one of the plurality of semiconductor light emitting devices is detected in real time, and when the first current is different from a preset reference current, the preset reference current flows through the any one of the semiconductor light emitting devices. A current compensator 1501 for compensating for a difference between the first current and a preset reference current may be included.

For example, the current compensator 1501 may be configured to adjust at least one of the semiconductor light emitting devices (LEDs) 1104 so that the current flowing through the semiconductor light emitting devices (LEDs) 1104 always becomes a preset reference current. Current flowing through one or more (eg, LED applied to a red sub-pixel) is detected in real time, and when the current flowing through any one semiconductor light emitting device is different from the preset reference current, the preset reference current is _{The set voltage (V SET )} applied to the operational amplifier 1502 to flow through the semiconductor light emitting device is adjusted.

The operational amplifier 1502 receives the voltage applied to the plurality of light emitting elements (LEDs) 1104 and the set voltage (V _SET ), and the voltage applied to the plurality of light emitting elements (LEDs) 1104 and the setting A difference _{between the voltages V SET} is applied to the driving unit 1103 . The value of the current flowing through the semiconductor light emitting device varies according to the voltage value of the set voltage V _{SET .}

_{The set voltage V SET} may be input to the non-inverting input terminal (+) of the operational amplifier 1502 , and a plurality of light-emitting elements (LEDs) 1104 may be input to the inverting input terminal (-) of the operational amplifier 1502 . ) can be input.

The data driver 1101 applies luminance information of the plurality of light emitting elements (LEDs) 1104 to the plurality of light emitting elements (LEDs) 1104 through the driver 1103 .

The gate driver 1102 controls the current level of the micro-IC, selects an input order of data, and counts the emission times of the plurality of light emitting devices (LEDs) 1104 .

A micro-IC (micro-IC) 1103 according to another embodiment of the present invention transmits data (Serial digital data) to a plurality of light emitting devices (LEDs) 1104 in a digital manner, and the digital data ( Since a digital comparator using digital data as it is is used, the size of the micro-IC (micro-IC) 1103 can be made smaller than that of a circuit using analog data.

In addition, the data driver 1101 according to another embodiment of the present invention can transmit digital data to a plurality of light emitting devices (LEDs) 1104 as it is, so that the size of the integrated circuit of the data driver 1101 is adjusted using analog data. It can be made smaller than the circuit.

As described above, the driving device of the LED display according to the embodiments of the present invention compensates for the driving thin film transistor (TFT) required in the semiconductor (Oxide and LTPS (Low Temperature Poly Silicon, etc.) substrate backplane process). , and the power supply voltage ELVDD for driving the pixel may be lowered.

The driving apparatus of the LED display according to the embodiments of the present invention may input data with a low voltage. For example, a silicon-based transistor having high mobility may be used, and power consumption when writing data may be reduced.

In the LED display driving apparatus according to embodiments of the present invention, a digital to analog converter (DAC) for converting digital data into analog data in the data driving unit is unnecessary. For example, since the driving device of the LED display according to the embodiments of the present invention applies data in a digital manner, a digital to analog converter (DAC) is unnecessary in the data driving unit.

In the LED display driving apparatus according to the embodiments of the present invention, since a digital to analog converter (DAC) is not required in the data driving unit, the size of the data driving unit may be reduced.

The LED display driving apparatus according to the embodiments of the present invention may compensate for a current deviation between a reference current and a current flowing in a semiconductor light emitting device applied to a sub-pixel in a display panel.

The driving device of the LED display according to the embodiments of the present invention can secure a wide current range, and is applicable to a tiling display.

Meanwhile, when an offset occurs in the input voltage of the operational amplifier 1502 or a deviation occurs in the resistance, a current deviation between the plurality of light emitting devices (LEDs) applied to the sub-pixels may occur. Accordingly, a driving device for an LED display that compensates for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel will be described below with reference to FIG. 16 .

16 is a block diagram illustrating a driving device for an LED display compensating for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel according to another embodiment of the present invention.

As shown in Figure 16, the driving device of the LED display according to another embodiment of the present invention,

a plurality of light emitting elements (LEDs) 1104 applied to sub-pixels included in the display panel;

a data driver 1101 for generating serial digital data for driving a plurality of light emitting devices (LEDs) 1104;

a gate driver 1102 for generating a driving signal for driving a plurality of light emitting devices (LEDs) 1104 in response to the scan signal V _scan;

It drives in a digital pulse width modulation (PWM) method, and includes a driving unit 1103 for driving a plurality of light emitting devices (LEDs) 1104 based on the serial digital data and the driving signal,

The driving unit 1103 further includes a compensating unit 1603 for compensating for a current deviation between the plurality of light emitting devices (LEDs). For example, the driving unit 1103 includes a PWM generating unit 1601 that generates a digital PWM signal; a switching unit 1602 connected to each of the plurality of semiconductor light emitting devices 1104 and switching the plurality of semiconductor light emitting devices according to the digital PWM signal; and a compensating unit 1603 connected between the switching unit 1602 and the ground, and compensating for a current deviation between the plurality of semiconductor light emitting devices 1104 .

The compensator 1603 not only compensates for a current deviation between the plurality of light emitting devices (LEDs), but also determines the magnitude (current value) of the current flowing through the plurality of light emitting devices (LEDs).

For example, the compensator 1603 may include a first resistor R connected in series to the switching unit 1602 connected in series to each of a plurality of light emitting devices (a plurality of LEDs applied to sub-pixels included in one pixel). _{SET1 ) and a second resistor R F1} electrically connected between a point between the switching unit 1602 and the first resistor R _SET1 and an inverting input terminal (−) of the operational amplifier 1502 .

The switching unit 1602 is connected in series to each of a plurality of light emitting devices (a plurality of LEDs applied to sub-pixels included in one pixel), and switches the plurality of light emitting devices (LEDs) according to a digital PWM signal. a first switch; _{and a second switch (eg, a transistor M 1} ) connected in series between the first switch and the compensator 1603 , and the gate of the second switch (eg, the transistor M ₁ ) is an operational amplifier 1502 ) is connected to the output terminal of For example, a first switch S1 for switching the first LED according to a digital PWM signal is connected in series to a first LED (eg, an LED applied to a red sub-pixel), and the first switch S1 A second switch (eg, a transistor M ₁ ) is electrically connected between and the compensator 1603 . A third switch S2 for switching the second LED according to a digital PWM signal is connected in series to the second LED (eg, the LED applied to the green sub-pixel), and the third switch S2 and the compensator ( 1603) between the fourth switch (eg, transistor M ₂ ) is electrically connected. A fifth switch S3 for switching the third LED according to a digital PWM signal is connected in series to the third LED (for example, the LED applied to the blue sub-pixel), and the fifth switch S3 and the compensator ( 1603) between the sixth switch (eg, transistor M ₃ ) is electrically connected.

The compensator 1603 is a second switch (eg, a transistor M ₁ ), a resistor (R _SET1 ) connected in series, and a second switch (eg, a transistor M ₁ ) and a resistor (R _SET1 ) A point between the resistor (R SET1 ) _{and a resistor R F1} electrically connected between the inverting input terminal (-) of the operational amplifier 1502 ; A fourth switch and a resistor (R _SET2) connected in series (for example, the transistor M _2), the fourth switch (e.g., transistor M ₂₎ and a resistor (R _SET2) between the point and the operational amplifier 1502 _{a resistor (R F2} ) electrically connected between the inverting input terminal (-); A sixth switch (e. G., Transistors M _3), the series resistor (R _SET3) connected to the sixth switch (e.g., transistor M ₃₎ and a resistor (R _SET3) between the point and the operational amplifier 1502 _{and a resistor R F3} electrically connected between the inverting input terminal (-).

Hereinafter, a compensator for compensating for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in the display panel will be described with reference to FIG. 17 .

17 is an exemplary diagram illustrating an operation of a compensator for compensating for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel according to another embodiment of the present invention.

Compensation unit according to another embodiment of the present invention, an offset occurs in the input voltage of the operational amplifier 1502, or a plurality of light emitting elements (LEDs) according to the resistance deviation of the plurality of light emitting elements (LEDs) themselves. Compensate for current deviation between

As shown in FIG. 17 , a first resistor R _{SET1 connected in series to a first switching unit M 1} for switching a first semiconductor light emitting device among a plurality of semiconductor light emitting devices, and the first switching unit ( M _{1 ) and a second resistor (R F1} ) electrically connected between a point between the first resistor (R _SET1 ) and an input terminal of the operational amplifier 1502 , and a second semiconductor light emitting device among the plurality of semiconductor light emitting devices A third resistor (R _SET2 ) connected in series to a second switching unit (M ₂ ) for switching devices, a point between the second switching unit (M ₂ ) and the third resistor (R _SET2 ), and the operational amplifier Assuming that there is _{a fourth resistor (R F2} ) electrically connected between the input terminals of 1502,

When the resistance value of the first resistor R _SET1 is high and the third resistor R _{SET2 is high, the current I LED1} flowing through the first semiconductor light emitting device _{decreases and the voltage V S1} applied to the first semiconductor light emitting device decreases. increases, resulting in a current deviation (ΔI). Accordingly, the compensator according to another embodiment of the present invention _{increases the current (I LED1} ) flowing through the first semiconductor light emitting device and decreases the current flowing _{through the current (I LED2} ) flowing through the second semiconductor light emitting device. A deviation between the current flowing through the semiconductor light emitting device _{(I LED1} ) and the current flowing through _{the second semiconductor light emitting device (I LED2} ) is compensated.

For example, the compensator according to another embodiment of the present invention may include: a first resistor R _SET1 and a fourth resistor R _F2 having the same resistance value; _{A second resistor (R F1} ) and a third resistor (R _SET2 ) having different resistance values to compensate for the deviation between the current flowing through the first semiconductor light emitting device (I _LED1 ) and the current flowing through the second semiconductor light emitting device (I _{LED2 )} ) may be included.

Hereinafter, a method of setting resistance values of resistors included in a compensator for compensating for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel will be described with reference to FIGS. 18 to 20 . do.

18 to 20 are a plurality of light emitting devices according to a change in resistance value of a compensator for compensating for a current deviation between a plurality of light emitting devices (LEDs) applied to sub-pixels included in a display panel according to another embodiment of the present invention; Exemplary diagrams showing changes in voltage and current between (LEDs).

As shown in FIG. 18 , _{the resistance values of the first resistor R SET1} , the third resistor R _SET2 , and the fifth resistor R _SET3 are set equal to 10 kΩ, and the second resistor R _When the resistance values of the F1 ), the fourth resistor R _F2 , and the sixth resistor R _F3 are maintained to be equal to 500Ω, the semiconductor light emitting device connected to _{the first resistor R SET1} and the second resistor R _{F1 )} the voltage across (V _F1) (for example, 2.5V) is the third resistor (R _SET2) and the fourth resistor voltage across the semiconductor light emitting device connected to the _{(R F2) (V F2)} ( for example, 3.1 V) lower than _{the voltage V F2} (eg, 3.7V) applied to the semiconductor light emitting device connected to _{the third resistor R SET2} and the fourth resistor R _{F2 is the fifth resistor R SET3 ) and the voltage (V F1} ) (eg, 3.7V) applied to the semiconductor light emitting device connected to the sixth resistor (R _{F3 ) is lowered.}

On the other hand, the current (eg, 10.212 μA) flowing through the semiconductor light emitting device connected to _{the first resistor R SET1} and the second resistor R _{F1 is the third resistor R SET2} and the fourth resistor R _{F2 .} ) is greater than the current flowing through the semiconductor light emitting device connected to (for example, 10.131 μA), and the current flowing through the semiconductor light emitting device connected to the third resistor R _SET2 and the fourth resistor R _F2 (for example, 10.131) μA) is smaller than the current (eg, 10.064 μA) flowing through the semiconductor light emitting device connected to the fifth resistor R _SET3 and the sixth resistor R _{F3 .}

Accordingly, the resistance values of the first resistor R _SET1 , the third resistor R _SET2 , and the fifth resistor R _SET3 are set to be equal to 10 kΩ, and the second resistor R _F1 , the fourth resistor When the resistance values of (R _F2 ) and the sixth resistor (R _F3 ) are maintained to be equal to 500Ω, a voltage deviation and a current deviation between the semiconductor light emitting devices 1801 occur.

As shown in FIG. 19 , the resistance value of _{the first resistor R SET1 is set to 8 kΩ, the resistance value of the third resistor R SET2} is set to 10 kΩ, and the fifth resistor R _SET3 ) If the resistance values of the resistors are set differently to 12kΩ, and the resistance values of the second resistor (R _F1 ), the fourth resistor (R _F2 ), and the sixth resistor (R _F3 ) are kept the same at 500Ω,

_{A voltage (V F1} ) (eg, 3.1V) applied to the semiconductor light emitting device connected to the first resistor (R _SET1 ) and the second resistor (R _F1 ), and the third resistor (R _SET2 ) and the fourth resistor A voltage applied to the semiconductor light emitting device connected to (R _{F2 ) (V F2} ) (eg, 3.1V), the _{voltage applied to the semiconductor light emitting device connected to the third resistor (R SET2} ) and the fourth resistor (R _F2 ) ( V _F2 ) (eg 3.1V) are equal to each other,

On the other hand, the _{resistance value of the first resistor (R SET1} ) is set to 8 kΩ, the resistance value of the third resistor (R _SET2 ) is set to 10 kΩ, and the resistance value of the fifth resistor (R _SET3 ) is set to 12 kΩ If set differently and the resistance values of the second resistor (R _F1 ), the fourth resistor (R _F2 ), and the sixth resistor (R _F3 ) are kept the same at 500Ω,

A current (eg, 10.506 μA) flowing through the semiconductor light emitting device connected to the first resistor (R _SET1 ) and the second resistor (R _{F1 ) is applied to the third resistor (R SET2} ) and the fourth resistor (R _F2 ) It is greater than the current flowing through the semiconductor light emitting device connected to it (for example, 10.391 μA), and the current flowing through the semiconductor light emitting device connected to the third resistor R _SET2 and the fourth resistor R _F2 (for example, 10.391 μA) is greater than the current (eg, 10.314 μA) flowing through the semiconductor light emitting device connected to the fifth resistor R _SET3 and the sixth resistor R _{F3 .}

Accordingly, the resistance values of the first resistor (R _SET1 ), the third resistor (R _SET2 ), and the fifth resistor (R _SET3 ) 1901 are set to be different from each other, and the second resistor (R _F1 ), the fourth When _{the resistance values of the resistor R F2} and the sixth resistor R _F3 are maintained to be equal to 500 Ω, there is no voltage deviation between the semiconductor light emitting devices 1801 but a current deviation occurs.

As shown in FIG. 20 , _{the resistance values of the first resistor R SET1} , the third resistor R _SET2 , and the fifth resistor R _SET3 are set to be equal to 10 kΩ, and the second resistor R _When the resistance value of F1 is set to 400Ω, the resistance value of the fourth resistor R _F2 is set to 500Ω, and the resistance value of the sixth resistor R _F3 is set differently to 600Ω, the first resistor ( A _{voltage (V F1} ) (eg, 3.1V) applied to the semiconductor light emitting device connected to _{R SET1} ) and the second resistor (R _F1 ), and the third resistor (R _SET2 ) and the fourth resistor (R _F2 ) the voltage across the semiconductor light emitting device is connected (V _F2) (for example, 3.1V), the third resistor (R _SET2) and the fourth resistor (R _F2) voltage (V _F2) applied to the semiconductor light-emitting device connected to the (e.g. For example, 3.1V) are equal to each other,

On the other hand, the _{resistance values of the first resistor (R SET1} ), the third resistor (R _SET2 ), and the fifth resistor (R _SET3 ) are set to be equal to 10 kΩ, and the resistance value of the second resistor (R _F1 ) is If it is set to 400Ω, _{the resistance value of the fourth resistor (R F2} ) is set to 500Ω, and the resistance value of the sixth resistor (R _F3 ) is set differently to 600Ω,

A current (eg, 10.134 μA) flowing through the semiconductor light emitting device connected to the first resistor (R _SET1 ) and the second resistor (R _{F1 ), the third resistor (R SET2} ) and the fourth resistor (R _F2 ) The current flowing through the semiconductor light emitting device connected (for example, 10.134 μA), the current flowing through the semiconductor light emitting device connected to the third resistor R _SET2 and the fourth resistor R _F2 (for example, 10.134 μA) is equal to each other without current deviation,

Accordingly, the resistance values of the first resistor (R _SET1 ), the third resistor (R _SET2 ), and the fifth resistor (R _SET3 ) 2001 are set to be the same, and the second resistor (R _F1 ), the fourth By setting the resistance values of the resistor R _F2 and the sixth resistor R _F3 to be different from each other, a voltage deviation and a current deviation between the semiconductor light emitting devices 1801 do not occur.

_{That is, the first resistor (R SET1} ), the third resistor (R _SET2 ), and the fifth resistor (R _SET3 ) connected to the first, second, and third semiconductor light emitting devices (LED) of each row line of the display panel (2001) set the same resistance values, and set the resistance value of the second resistor R _F1 connected to the first semiconductor light emitting device LED of each row line of the display panel to each row line of the display panel. _{Set lower than the resistance value of the second resistor R F2} connected to the second semiconductor light emitting device (LED) of the row line, and the second semiconductor light emitting device (LED) of each row line of the display panel By setting the resistance value of the connected fourth resistor R _F2 to be lower than the resistance value of _{the sixth resistor R F3} connected to the third semiconductor light emitting device LED of each row line of the display panel, from the first A voltage deviation and a current deviation between the third semiconductor light emitting devices 1801 do not occur.

The first resistor (R _SET1 ), the third resistor (R _SET2 ), and the fifth resistor (R _SET3 ) may be fixed resistors, the second resistor (R _F1 ), the fourth resistor (R _F2 ), The sixth resistor R _{F3 may be variable resistors, and the driver 1103 controls the second resistor R F1} and the fourth resistor R so that a voltage deviation and a current deviation between the semiconductor light emitting devices 1801 do not occur. _F2 ) and resistance values of the sixth resistors R _F3 may be varied.

On the other hand, the first resistor (R _SET1 ), the third resistor (R _SET2 ), the fifth resistor (R _SET3 ), the second resistor (R _F1 ), the fourth resistor (R _F2 ), a sixth resistor ( R _{F3 ) may be variable resistors, and the driving unit 1103 includes the first resistor R SET1} , the third resistor R _SET2 so that a voltage deviation and a current deviation between the semiconductor light emitting devices 1801 do not occur. Resistance values of the fifth resistor R _SET3 , the second resistor R _F1 , the fourth resistor R _F2 , and the sixth resistor R _F3 may be varied.

As described above, the LED display driving apparatus according to the embodiments of the present invention can improve the image quality of the display by compensating for a current deviation between the plurality of semiconductor light emitting devices applied to the sub-pixels in the display panel.

The LED display driving apparatus according to the embodiments of the present invention may improve the image quality of the display by compensating for a current deviation between the reference current and the current flowing in the semiconductor light emitting device applied to the sub-pixel in the display panel.

The driving device of the LED display according to the embodiments of the present invention drives a digital panel in a digital PWM method and uses serial digital data as it is, so that a semiconductor (Oxide and LTPS (Low temperature poly silicon, etc.) substrate backplane) There is no need to compensate the driving thin film transistor (TFT) required in the process, and the power supply voltage ELVDD for driving the pixel can be reduced.

The LED display driving apparatus according to the embodiments of the present invention drives a digital panel using a digital PWM method and uses serial digital data as it is, so that data can be input at a low voltage. For example, a silicon-based transistor having high mobility may be used, and power consumption when writing data may be reduced.

In the LED display driving apparatus according to embodiments of the present invention, a digital to analog converter (DAC) for converting digital data into analog data in the data driving unit is unnecessary. For example, since the driving device of the LED display according to the embodiments of the present invention applies data in a digital manner, a digital to analog converter (DAC) is unnecessary in the data driving unit.

In the LED display driving apparatus according to the embodiments of the present invention, since a digital to analog converter (DAC) is not required in the data driving unit, the size of the data driving unit may be reduced.

The LED display driving apparatus according to embodiments of the present invention may compensate for a current deviation between a current flowing in a semiconductor light emitting device applied to a sub-pixel in a display panel and a reference current.

The driving device of the LED display according to the embodiments of the present invention can secure a wide current range, and is applicable to a tiling display.

The LED display driving apparatus according to embodiments of the present invention may reduce the size of the PWM generator that generates the digital PWM signal. For example, the size of the PWM generator may be reduced by removing a shift register from the existing digital PWM signal generator.

Those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (10)

A display device for applying a digital pulse width modulation (PWM) signal to a plurality of sub-pixels included in a pixel of a display panel, the display device comprising:
a plurality of semiconductor light emitting devices applied to sub-pixels included in pixels of the display panel;
A driving unit for driving the plurality of semiconductor light emitting devices based on a digital pulse width modulation (PWM) signal,
The driving unit includes a compensating unit for compensating for voltage deviation between the plurality of semiconductor light emitting devices,
The compensation unit,
a plurality of switching units connected in series to each of the plurality of semiconductor light emitting devices and configured to switch the plurality of semiconductor light emitting devices according to the digital PWM signal;
an operational amplifier for applying a difference between a voltage applied to the plurality of semiconductor light emitting devices and a set voltage to the driving unit;
a first resistor unit including a plurality of resistors connected in series to each of the plurality of switching units; and,
a second resistor unit including a plurality of resistors connected between a point between each switching unit and a resistor of the first resistor unit and an inverting input terminal (-) of the operational amplifier,
A plurality of resistors constituting one of the first resistor unit and the second resistor unit have the same resistance value, and the plurality of resistors constituting the other one have different resistance values. According to claim 1, wherein the compensation unit,
A display device, characterized in that connected between the switching unit and the ground. According to claim 1,
The display device, characterized in that the driving unit comprises a PWM generator for generating the digital PWM signal. According to claim 1, wherein the compensation unit,
and compensating for a deviation between a current flowing through a first semiconductor light emitting device and a current flowing through a second semiconductor light emitting device among the plurality of semiconductor light emitting devices. delete According to claim 1,
A plurality of resistors constituting the first resistor unit have the same resistance value,
A plurality of resistors constituting the second resistor unit are formed to have different resistance values,
The compensator further compensates for a current deviation between the plurality of semiconductor light emitting devices. The method of claim 6, wherein the compensation unit,
and compensating for the current deviation and simultaneously determining values of currents flowing through the plurality of semiconductor light emitting devices. 7. The method of claim 6,
A plurality of resistors constituting the first resistor unit are fixed resistors having the same resistance value,
A plurality of resistors constituting the second resistor unit are variable resistors having different resistance values,
The display device of claim 1, wherein the driver varies resistance values of the variable resistors so that a current deviation between the plurality of semiconductor light emitting devices does not occur. According to claim 1,
and the driving unit is one micro integrated circuit, the one micro integrated circuit drives a plurality of pixels, and each of the plurality of pixels includes a plurality of sub-pixels. According to claim 1,
A first current flowing through at least one of the plurality of semiconductor light emitting devices is detected in real time, and when the first current is different from a preset reference current, the preset reference current flows through the any one of the semiconductor light emitting devices. The display device further comprising a current compensator for compensating for a difference between the first current and a preset reference current.

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