KR102299857B1 - Display device using semiconductor light emitting device - Google Patents

Abstract

In the display device according to the present invention, the display device according to the present invention is coupled to a wiring board having a plurality of electrode lines, a conductive adhesive layer connected to the wiring board, and the conductive adhesive layer, and is electrically connected to the plurality of electrode lines. a plurality of connected semiconductor light emitting devices, a red phosphor part disposed along any one of the plurality of electrode lines, and converting light emitted from the semiconductor light emitting devices arranged along any one line into red; and a green phosphor part disposed along another one of the plurality of electrode lines and converting light emitted from the semiconductor light emitting devices arranged along the other line into green, wherein the red and green phosphor parts are included. The fluorescent regions are characterized in that they are spaced apart from each other with a spacer therebetween.

Description

Display device using semiconductor light emitting device {DISPLAY DEVICE USING SEMICONDUCTOR LIGHT EMITTING DEVICE}

The present invention relates to a display device, and more particularly, to a display device using a semiconductor light emitting device.

Recently, in the field of display technology, display devices having excellent characteristics, such as thin and flexible, have been developed. In contrast, currently commercialized main displays are represented by LCD (Liguid Crystal Display) and AMOLED (Active Matrix Organic Light Emitting Diodes).

On the other hand, such a display device, visibility varies according to ambient brightness, and the outdoor display device generally requires a higher luminance than the indoor display device.

SUMMARY OF THE INVENTION One object of the present invention is to provide a display device capable of securing visibility in response to a change in ambient brightness.

Another object of the present invention is to provide a driving circuit and a method for changing the brightness of a display device in order to improve visibility of the display device in various ambient light environments, such as at night, indoors, and outdoors.

The display device according to the present invention includes a data electrode line, a semiconductor light emitting device electrically connected to the data electrode line, and receiving a current supplied through the data electrode line, the data electrode line and the semiconductor light emitting device electrically connected, controlling the current mirror unit to control the amount of current supplied to the semiconductor light emitting device through the data electrode line and the current mirror unit to vary the amount of current supplied to the semiconductor light emitting device based on ambient illuminance It is characterized in that it comprises a control unit.

In an embodiment, the controller drives the current mirror unit in any one of a first operation mode and a second operation mode based on the ambient illuminance, and controls the semiconductor light emitting device in the first operation mode. The amount of supplied current is greater than the amount of current supplied to the semiconductor light emitting device in the second operation mode.

In an embodiment, the peripheral illuminance corresponding to the first operation mode is greater than the peripheral illuminance corresponding to the second operation mode.

In an embodiment, the control unit controls the current supplied to the data electrode line in a PWM (Pulse Width Modulation) method, and the pulse voltages in the first operation mode and the second operation mode are different from each other. do.

In an embodiment, the pulse voltage in the first operation mode is greater than the pulse voltage in the second operation mode.

In an embodiment, the amount of current supplied to the semiconductor light emitting device in the first operation mode is greater than the amount of current supplied to the semiconductor light emitting device in the second operation mode, and the pulse voltage in the first operation mode is greater than the pulse voltage in the second operation mode.

In an embodiment, it further comprises an illuminance sensor unit for sensing ambient illuminance, wherein the control unit controls the amount of current supplied to the semiconductor light emitting device by using the sensing result through the illuminance sensor unit. .

In an embodiment, the controller increases the amount of current supplied to the semiconductor light emitting device by controlling the current mirror when the peripheral illuminance is greater than a preset reference as a result of the sensing, and the sensing result, the peripheral illuminance When is smaller than a preset reference, the current mirror unit is controlled to reduce the amount of current supplied to the semiconductor light emitting device.

According to the present invention, a display device including a semiconductor light emitting device supplied with a current through an electrical connection with a data electrode line according to the present invention includes the steps of sensing ambient illuminance, and when the sensed peripheral illuminance is greater than a reference illuminance, the semiconductor light emitting device and controlling a current mirror part electrically connected to the data electrode line and the semiconductor light emitting device to increase the amount of current supplied to the device.

In an embodiment, the current supplied to the data electrode line is controlled by a pulse width modulation (PWM) method, and when the sensed peripheral illuminance is greater than a reference illuminance, a pulse voltage is increased.

According to the present invention, the visibility of the display device can be secured by changing the amount of current supplied to the display device according to the change in ambient illuminance. Through this, it is possible to provide a display device that is not limited by various ambient light environments, such as at night, indoors, and outdoors.

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 method of supplying current to a display device according to the present invention.
11 is a flowchart illustrating a method of supplying current to a display device according to the present invention.
12 is a conceptual diagram for explaining the current supply method illustrated in FIGS. 10 and 11 .
13 is a conceptual diagram for explaining a plurality of modes in which current supply amounts are different from each other.

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, G, and B.

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 , FIG. 3 is a cross-sectional view 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 , and FIGS. 5A to 5C . are conceptual diagrams 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. Also, a 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 a 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 183 , 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 coupled.

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 the 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 the 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 conceptual diagram illustrating the vertical semiconductor light emitting device of FIG. 8 . am.

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 is preferably 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 a 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.

Hereinafter, a method of providing a display device capable of securing visibility in response to a change in ambient brightness will be described in more detail with reference to the accompanying drawings. 10 is a block diagram illustrating a method of supplying current to a display device according to the present invention, FIG. 11 is a flowchart illustrating a method of supplying current to a display device according to the present invention, and FIG. 12 is FIG. and a conceptual diagram for explaining the current supply method illustrated in FIG. 11 . And, FIG. 13 is a conceptual diagram for explaining a plurality of modes in which current supply amounts are different from each other.

First, as shown in FIG. 10 , the display device according to the present invention includes a controller 1010 and a current mirror unit ( 1015) may be included.

Meanwhile, as described above, the semiconductor light emitting device 1051 is connected to the first electrode part 1020 and the second electrode part 1030 to supply an operating current or operating power to drive the semiconductor light emitting device 1051 . You can get it. Here, the first electrode part 1020 and the second electrode part 1030 are electrically connected to the plurality of semiconductor light emitting devices 1051 . The first electrode unit 1020 may serve as a data electrode, and the second electrode unit 1030 may function as a scan electrode.

The first electrode unit 1020 serving as a data electrode may be composed of a plurality of data electrode lines. The semiconductor light emitting device 1051 may operate by receiving current through the data electrode line corresponding to the first electrode part 1020 .

In this case, the controller 1010 may adjust the amount of current supplied through the data electrode line based on the ambient illuminance. The brightness of the semiconductor light emitting device 1051 when the amount of current supplied to the semiconductor light emitting device 1051 is large is the brightness of the semiconductor light emitting device 1051 when the amount of current supplied to the semiconductor light emitting device 1051 is small. brighter than

That is, the luminance of the semiconductor light emitting device 1051 when the amount of current supplied to the semiconductor light emitting device 1051 is large is the same as the luminance of the semiconductor light emitting device 1051 when the amount of current supplied to the semiconductor light emitting device 1051 is small. greater than the luminance of

For example, in a bright environment due to sunlight, that is, when the peripheral illuminance of the display device is large, in order to ensure visibility of the display device, the amount of current flowing through the semiconductor light emitting device 1051 must be large. And, in a dark environment, that is, when the peripheral illuminance of the display device is small, the amount of current flowing through the semiconductor light emitting device 1051 is relatively smaller than the amount of current in a bright environment.

Accordingly, in the present invention, it is possible to propose a control method capable of immediately responding to the illuminance according to the surrounding environment by adjusting the amount of current flowing through the semiconductor light emitting device 1051 according to the ambient illuminance.

Referring to the control method for controlling the amount of current flowing through the semiconductor light emitting device 1051 with reference to FIG. 11 , first, a step of sensing the ambient illuminance of the display device is performed ( S1110 ).

The display device according to the present invention may further include an illuminance sensor unit for sensing ambient illuminance. The sensing of ambient illuminance may be performed in real time, or may be performed at a preset time interval.

Meanwhile, when the peripheral illuminance is sensed, a step of comparing the sensed peripheral illuminance with the reference illuminance is performed (S1120). Then, a step of controlling the amount of current supplied to the semiconductor light emitting device 1051 according to the comparison result is performed (S1130).

Here, the reference illuminance may be preset from the time the product is shipped, otherwise it may be set based on a user's selection.

In the display device according to the present invention, when the peripheral illuminance corresponds to the reference illuminance, the amount of current flowing through the semiconductor light emitting device 1051 may be preset. Accordingly, when i) the peripheral illuminance corresponds to the reference illuminance or ii) the difference between the peripheral illuminance and the reference illuminance is within a preset range, the controller 1010 determines the amount of current flowing through the semiconductor light emitting device 1051, the reference It can be controlled by the amount of current according to the illuminance.

In addition, the control unit 1010, when the difference between the sensed peripheral illuminance and the reference illuminance, is out of the preset range, the amount of current flowing through the semiconductor light emitting device 1051 is higher than the amount of current according to the reference illuminance. You can control more or less.

Meanwhile, the display device according to the present invention may be driven in any one of a visibility mode (or a first operation mode) or a normal mode (or a second operation mode) according to ambient illuminance.

More specifically, when the sensed peripheral illuminance is greater than the reference illuminance and the difference between the sensed peripheral illuminance and the reference illuminance is greater than or equal to a preset range (or greater than the preset range), the control unit 1010, The display device may be driven in the visibility mode. The visibility mode may refer to a mode in which an ambient light environment is bright, and an amount of current flowing through the semiconductor light emitting device 1051 is relatively larger than that of the general mode in order to ensure visibility of the display device.

That is, the amount of current supplied to the semiconductor light emitting device 1051 in the visibility mode (or the first operation mode) is greater than the amount of current supplied to the semiconductor light emitting device in the normal mode (or the second operation mode).

Meanwhile, when the sensed ambient illuminance is less than the reference illuminance, the controller 1010 may drive the display device in the normal mode.

The controller 1010 may change the driving mode of the display device when the sensed peripheral illuminance is smaller than the reference illuminance as a result of sensing the peripheral illuminance while the display device is being driven in the visibility mode. In this case, the driving mode of the display apparatus may be switched from the visibility mode to the normal mode.

Furthermore, the controller 1010 may change the driving mode of the display device when the sensed ambient illuminance is greater than the reference illuminance as a result of sensing the peripheral illuminance while the display device is being driven in the normal mode. In this case, the driving mode of the display apparatus may be switched from the normal mode to the visibility mode.

Furthermore, the controller 1010, in a state in which the display device is being driven in the normal mode, senses the ambient illuminance, and when the sensed peripheral illuminance is smaller than the reference illuminance, continues the driving mode of the display device in the normal mode, can keep

Furthermore, the controller 1010, in a state in which the display device is being driven in the visibility mode, senses the peripheral illuminance, and when the sensed peripheral illuminance is greater than the reference illuminance, the driving mode of the display device is continued to the visibility mode. can keep

Hereinafter, a method for controlling the amount of current provided to the semiconductor light emitting device in the visibility mode and the normal mode will be described in more detail.

Referring to FIG. 12 , the controller 1010 of the display device according to the present invention may further include a voltage variable regulator and a pulse generator.

The current mirror unit 1015 may include Q1, Q2, Q3 switches, Rset, and Rbr resistors. As shown, the Q1 and Q2 switches correspond to a constant current circuit for constantly controlling the current If flowing through the data electrode line, and the Q3 switch controls the supplied current Iref in the visibility mode and the normal mode. It corresponds to a switch to change.

The Rset resistor is a resistor for setting the Iref current, and the Rbr resistor is a resistor for increasing the amount of current in the visibility mode.

The controller 1010 may change the Iref current to differently control the amount of current flowing through the semiconductor light emitting device in the visibility mode and the normal mode included in the current mirror unit 1015 . The change in the Iref current may be made by controlling the Q3 switch, Rset, and Rbr resistors, that is, the current mirror unit 1015 under the control of the controller 1010 .

On the other hand, the Q4 switch corresponds to a switch for electrically connecting the second electrode part 1030 (or, the scan electrode, the scan electrode line) and the semiconductor light emitting device 1051 so that a current flows through the semiconductor light emitting device 1051 . .

As described above, the controller 1010 may increase or decrease the amount of current If flowing through the data electrode line by controlling the current mirror unit 1015 .

On the other hand, in the visibility mode, since the amount of current supplied to the semiconductor light emitting device is larger than in the general mode, when only the magnitude of the current is changed, the power consumption is sharply increased due to the increase of the driving voltage by the scan electrode (or the second electrode). can increase

Accordingly, in the present invention, by increasing the pulse voltage in PWM (Pulse Width Modulation) control for driving the semiconductor light emitting device, the driving voltage VDD is increased in the visibility mode than in the general mode, thereby reducing the current required in the visibility mode. It is possible to increase the luminance of the semiconductor light emitting device 1051 while reducing the amount.

That is, in order to secure the brightness of the semiconductor light emitting device 1051 required in the visibility mode, the controller 1010 does not only increase the amount of current, but sets the driving voltage to a higher driving voltage than the driving voltage VDD in the normal mode. By varying , the amount of current is reduced, but the brightness of the semiconductor light emitting device 1051 can be secured.

As such, when the amount of current supplied in the visibility mode is reduced, power consumption of the scan electrode can be reduced. That is, the control unit 1010 may reduce power consumption by changing the driving voltage VDD according to the PWM control method when converting from the normal mode to the visibility mode.

Meanwhile, the controller 1010 may adjust the driving voltage VDD during PWM control differently from each other according to the PWM control method in the normal mode and the visibility mode. The driving voltage may be changed through the previously described voltage variable regulator.

More specifically, as a result of sensing the peripheral illuminance, the controller 1010 drives the display device in the normal mode when the sensed peripheral illuminance is less than the reference illuminance. The driving voltage in the normal mode may be VDD1, and the current flowing through the data electrode line may be If1.

Then, as a result of sensing the peripheral illuminance, when the sensed peripheral illuminance is greater than the reference illuminance, the controller 1010 drives the display device in the viewing mode. The driving voltage in the visibility mode may be VDD2, and the current flowing through the data electrode line may be If2.

As illustrated, the driving voltage VDD1 in the normal mode is smaller than the driving voltage VDD2 in the visibility mode. That is, the controller 1010 may reduce power consumption of the display device by differently controlling the pulse voltages in the normal mode and the visibility mode through the voltage variable regulator.

Furthermore, the amount of the current If1 flowing to the data electrode line in the normal mode is less than the driving current If2 in the visibility mode. That is, the controller 1010 may control the luminance of the display apparatus by controlling the current mirror unit 1015 to differently control the supply current in the normal mode and the visibility mode.

As described above, the controller 1010 according to the present invention controls the current mirror unit 1015 in a visibility mode (or a first operation mode) and a normal mode (or a second operation mode) based on the sensed ambient illuminance. drive in any one operating mode. The amount of current supplied to the semiconductor light emitting device 1051 in the visibility mode is greater than the amount of current supplied to the semiconductor light emitting device 1051 in the normal mode.

Furthermore, as described above, the gating and control unit 1010 not only control only the amount of current flowing through the semiconductor light emitting device 1051, but also use a voltage variable regulator to change the driving voltage corresponding to the pulse voltage, It is possible to reduce power consumption while ensuring the brightness of the display device.

As described above, the display device according to the present invention can secure the visibility of the display device in the visibility mode by controlling the amount of current supplied to the semiconductor light emitting device in the visibility mode and the normal mode. Through this, it is possible to provide a display device that is not limited by various ambient light environments, such as at night, indoors, and outdoors.

Furthermore, in the display device according to the present invention, power consumption in the display device can be reduced by increasing the driving voltage in the visibility mode.

Alternatively, the controller 1010 may compare the sensed ambient illuminance with illuminance corresponding to the amount of current flowing through the semiconductor light emitting device 1051 . In this case, when the sensed peripheral illuminance is greater than the illuminance corresponding to the amount of current flowing through the semiconductor light emitting device, the controller 1010 transmits the current flowing through the semiconductor light emitting device 1051 to the current flowing through the semiconductor light emitting device 1051 . The current mirror unit 1015 may be controlled so that a large current may flow. Conversely, when the sensed peripheral illuminance is less than the illuminance corresponding to the amount of current flowing through the semiconductor light emitting device, the controller 1010 controls the semiconductor light emitting device 1051 to control the current flowing through the semiconductor light emitting device 1051 . The current mirror unit 1015 may be controlled so that a small current may flow. Meanwhile, since the method for controlling the current mirror unit 1051 and specific concepts thereof are the same as those described above, a detailed description thereof is replaced with the previous description.

On the other hand, even in the case of controlling the brightness of the semiconductor light emitting device 1051 by comparing the sensed peripheral illuminance with the illuminance corresponding to the amount of current flowing through the semiconductor light emitting device 1051, as described above, The control for varying the pulse voltage can be equally applied. A detailed description thereof is substituted for the description described above.

Claims (10)

data electrode line;
a semiconductor light emitting device electrically connected to the data electrode line and receiving a current supplied through the data electrode line;
a current mirror part electrically connected to the data electrode line and the semiconductor light emitting device, and controlling an amount of current supplied to the semiconductor light emitting device through the data electrode line; and
Based on the ambient illuminance, the current mirror unit is driven in any one of a first operation mode and a second operation mode, and the current supplied to the data electrode line is controlled in a PWM (Pulse Width Modulation) method to control the current to be supplied to the data electrode line. and a control unit for controlling the current mirror unit to vary the amount of current supplied to the light emitting device,
The display apparatus of claim 1, wherein pulse voltages are different from each other in the first operation mode and the second operation mode. delete According to claim 1,
The display device, characterized in that the peripheral illuminance corresponding to the first operation mode is greater than the peripheral illuminance corresponding to the second operation mode. delete delete According to claim 1,
The amount of current supplied to the semiconductor light emitting device in the first operation mode is greater than the amount of current supplied to the semiconductor light emitting device in the second operation mode,
The display apparatus of claim 1, wherein the pulse voltage in the first operation mode is greater than the pulse voltage in the second operation mode. According to claim 1,
Further comprising an illuminance sensor unit for sensing ambient illuminance,
The control unit is
The display device according to claim 1, wherein the amount of current supplied to the semiconductor light emitting device is controlled by using the sensing result of the illuminance sensor unit. 8. The method of claim 7,
The control unit is
As a result of the sensing, when the peripheral illuminance is greater than a preset reference, controlling the current mirror to increase the amount of current supplied to the semiconductor light emitting device;
As a result of the sensing, when the peripheral illuminance is less than a preset reference, the display device according to claim 1, wherein the amount of current supplied to the semiconductor light emitting device is reduced by controlling the current mirror unit. A method of controlling a display device including a semiconductor light emitting device receiving current through an electrical connection with a data electrode line, the method comprising:
sensing ambient illuminance; and
and controlling a current mirror part electrically connected to the data electrode line and the semiconductor light emitting device to increase the amount of current supplied to the semiconductor light emitting device when the sensed peripheral illuminance is greater than the reference illuminance,
The current supplied to the data electrode line is controlled by a PWM (Pulse Width Modulation) method,
When the sensed peripheral illuminance is greater than the reference illuminance, a pulse voltage is increased. delete

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