KR100866841B1 - Color controllable OLED by using piezoelectric thin firm - Google Patents

Abstract

The present invention relates to an LED that can be controlled color using a piezoelectric thin film, the substrate; A first conductive layer deposited on the substrate and connected to the anode of the first variable battery; A piezoelectric thin film deposited on the first conductive layer, the thickness of which is increased or decreased according to the increase or decrease of the electrical signal intensity of the first variable battery; A second conductive layer deposited on the piezoelectric thin film and connected to a ground of the first variable battery and the cathode of the first battery; A light emitting layer deposited on the second conductive layer, and having electrons and holes from the first battery recombined to form excitons, wherein a specific wavelength of light is generated by the formed excitons; A third conductive layer deposited on the light emitting layer and connected to the anode of the first battery; A first variable battery connected to the first conductive layer and the second conductive layer to control the thickness of the piezoelectric thin film by an electrical signal; And a first battery connected to the second conductive layer and the third conductive layer to inject electrons and holes into the light emitting layer. It includes.

According to the present invention as described above, when an electric signal is applied to the inside of the LED element by using the color of the light emitting color changes according to the thickness of the inner layer of the LED element inserts a piezoelectric thin film whose thickness is controlled and the electric signal It is effective to control the light emission color by applying to the element and adjusting the thickness of the piezoelectric thin film.

OEL ID, Piezoelectric Thin Film, Luminescent, Color Control

Description

Color controllable OLED by using piezoelectric thin firm}

1 is a cross-sectional view of an upper light emitting structure of an LED according to a first embodiment of the present invention.

2 is a cross-sectional view of a bottom light emitting structure of an LED according to a second embodiment of the present invention.

<Description of Symbols in Drawings>

100: upper LED light emitting element 110: substrate

120: first conductive layer of the top emission OLED 130: piezoelectric thin film

140: second conductive layer of top emitting OLED 150: emitting layer

160: third conductive layer of the top emitting OLED 170: first variable battery

180: first battery

200: lower light emitting element of OLED 210: glass substrate

220: first conductive layer of the lower emitting OLED ID 230: piezoelectric thin film

240: second conductive layer of the bottom light emitting OLED 250: light emitting layer

260: third conductive layer of bottom emitting OID 270: second variable battery

280: secondary battery

The present invention relates to an OEL LED capable of color control by using a piezoelectric thin film, and more particularly, by using a phenomenon in which a thickness is changed when a piezoelectric thin film is inserted into an ODL element to apply voltage to the piezoelectric thin film. By controlling the thickness of the device, the color control is possible by using a piezoelectric thin film of the LED can be related.

In general, organic light emitting diodes (OLEDs) are excellent in terms of response speed, high resolution, wide viewing angle, ultra light weight, ultra thin film, and high brightness, and are promising technologies for next generation displays. In particular, OLED display is a display using a device in the form of a solid film, and is used as a core component of the display area such as mobile communication terminals, monitors, TVs, and laptops according to the development of the technology level, and even the flexible large display of the large billboard Application is possible.

Using the microcavity effect, it is possible to adjust the emission color of the OLED. The microcavity effect allows only certain wavelengths to escape by the reflective top layer and device length of the OID device.

In a recent study, white OLEDs based on fluorescent emitter components realized color control of white light. This is proven to be the most promising in terms of long life and high efficiency. However, in the implementation of the color, the OLED to control and change the emission color of the device itself as an electrical signal has not been reported so far.

An object of the present invention is to insert a piezoelectric thin film whose thickness is controlled when an electrical signal is applied to the inside of the LED element by using the color of light emitted according to the thickness of the inner layer of the LED element, and the electrical signal is inputted. The present invention provides an LED which can be controlled in color by using a piezoelectric thin film for controlling the color of light emission by applying it to an LED element and adjusting the thickness of the piezoelectric thin film.

In accordance with an embodiment of the present invention, color controllable by using a piezoelectric thin film OEL LED, the color control is possible using a piezoelectric film, the substrate; A first conductive layer deposited on the substrate and connected to an anode of a first variable battery, which will be described later; A piezoelectric thin film deposited on the first conductive layer, the thickness of which is increased or decreased according to the increase or decrease of the electrical signal strength of the first variable battery; A second conductive layer deposited on the piezoelectric thin film and connected to a ground of the first variable battery and the negative electrode of the first battery; A light emitting layer deposited on the second conductive layer, the electrons of the second conductive layer of the first battery and holes of the third conductive layer are recombined to form excitons, and a light wavelength of the light generated by the formed excitons; A third conductive layer deposited on the light emitting layer and connected to the anode of the first battery; A first variable battery connected to the first conductive layer and the second conductive layer to control the thickness of the piezoelectric thin film by an electrical signal; And a first battery connected to the second conductive layer and the third conductive layer to inject electrons and holes into the light emitting layer. It includes.

Preferably, the first conductive layer is a reflective metal thin film, characterized in that to reflect the wavelength of light generated in the light emitting layer to the inside.

More preferably, when the electrical signal is applied through the first variable battery, the piezoelectric thin film has a thickness change rate of 8 to 12% compared to the thickness when the electrical signal is not applied according to its intensity. It is done.

In addition, the material of the piezoelectric thin film is characterized in that the piezoceramic (PZT), transparent ceramic (PLZT), zinc oxide (ZnO) or aluminum nitride (AIN).

Also preferably, the second conductive layer is a transparent conductor having a low work function.

Preferably, the third conductive layer is a semi-transmissive metal thin film, and emits a part of the wavelength of light generated in the light emitting layer to the outside and reflects the part to the inside.

On the other hand, the color of the LED can be controlled using a piezoelectric thin film, comprising: a first conductive layer deposited on a transparent glass substrate plate, and connected to the anode of the second variable battery; A piezoelectric thin film deposited on the first conductive layer, the thickness of which is increased or decreased as the electrical signal intensity of the second variable battery is increased or decreased; A second conductive layer deposited on the piezoelectric thin film and grounded to the negative electrodes of the second variable battery and the second battery; A light emitting layer deposited on the second conductive layer, the electrons of the second conductive layer and the holes of the third conductive layer are recombined to form excitons, and a specific wavelength of light is generated by the formed excitons; A third conductive layer deposited on the light emitting layer and connected to the anode of the second battery; A second variable battery connected to the first conductive layer and the second conductive layer to control the thickness of the piezoelectric thin film with an electrical signal; And a second battery connected to the second conductive layer and the third conductive layer to inject electrons and holes into the light emitting layer. It includes.

Preferably, the first conductive layer is a semi-transmissive metal thin film, characterized in that to emit a portion of the wavelength of the light emitted from the light emitting layer to the outside, and reflects a portion to the inside.

More preferably, when the electrical signal is applied through the first variable battery, the piezoelectric thin film has a thickness change rate of 8 to 12% compared to the thickness when the electrical signal is not applied according to its intensity. It is done.

In addition, the material of the piezoelectric thin film is characterized in that the piezoceramic (PZT), transparent ceramic (PLZT), zinc oxide (ZnO) or aluminum nitride (AIN).

Also preferably, the second conductive layer is a transparent conductor having a low work function.

And preferably, the third conductive layer is a reflective metal thin film, characterized in that to reflect the wavelength of light generated in the light emitting layer to the inside.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are defined in the technical spirit of the present invention on the basis of the principle that the inventor can appropriately define the concept of the term in order to explain his invention in the best way. It should be interpreted to mean meanings and concepts. In addition, when it is determined that the detailed description of the known function and its configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, it should be noted that the detailed description is omitted.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

With reference to FIG. 1, an ODL capable of color control using the piezoelectric thin film according to the first embodiment of the present invention will be described.

1 is a cross-sectional view of an upper light emitting structure of an LED which is color controlled using a piezoelectric thin film according to a first embodiment of the present invention.

As shown in FIG. 1, the upper light emitting structure 100 of the LEDs capable of color control using the piezoelectric thin film includes a substrate 110, a first conductive layer 120, a piezoelectric thin film 130, and a second conductive layer. 140, a light emitting layer 150 and a third conductive layer 160 are sequentially deposited, and include a first variable battery 170 and a first battery 180.

The material of the substrate 110 is plastic or film, and performs the base function of the ODL element.

In addition, the first conductive layer 120 is a reflective metal thin film, which is deposited on the substrate 110 and connected to the anode of the first variable battery 170.

In addition, the piezoelectric thin film 130 is made of a piezoelectric ceramic (PZT) material and is deposited on the first conductive layer 120, and when its electrical signal is applied through the first variable battery 170, its thickness according to its strength. The thickness changes by 8 to 12%, preferably 10%, compared to the thickness when no electrical signal is applied.

In this embodiment, the material of the piezoelectric thin film is set to a piezoelectric ceramic (PZT) material, but the present invention is not limited thereto, in addition to transparent ceramic (PLZT), zinc oxide (ZnO), or aluminum nitride (AIN). It is also possible to set.

In addition, the second conductive layer 140 is a transparent conductor having a low work function, is deposited on the piezoelectric thin film 130, and is grounded to the cathodes of the first variable battery 170 and the first battery 180. . In this case, the second conductive layer 140 is a transparent conductor having a low work function is a function of drawing electrons by receiving an electrical signal.

In addition, the emission layer 150 is deposited on the second conductive layer 140, and electrons of the second conductive layer 140 by the first battery and holes of the third conductive layer 160 are recombined to excite excitons. And a specific wavelength of light by the formed excitons.

In addition, the third conductive layer 160 is a semi-transmissive metal thin film, which is deposited on the light emitting layer 150, is connected to the anode of the first battery 180, and transmits a part of the wavelength of the light emitted by the light emitting layer to the outside. Emits and reflects a part inside.

In addition, the first variable battery 170 has a negative electrode connected to the second conductive layer 140 and a positive electrode connected to the third conductive layer 160, and the intensity of an electrical signal is varied. The thickness of the thin film 130 is adjusted.

In addition, the first battery 180 has an anode connected to the third conductive layer 160 to inject holes, and a cathode is formed on the cathode of the second conductive layer 140 and the first variable battery 170. Connected to ground to inject electrons.

Referring to the color control process of the color LED control is possible using the piezoelectric thin film according to the first embodiment of the present invention having the above-described configuration as follows.

The second conductive layer 140 is applied to the cathode by the first battery 180, and the third conductive layer 160 is applied to the anode by the first battery 180. Here, excitons are formed by electrons of the second conductive layer 140 and holes of the third conductive layer 160 moving to the light emitting layer 150 to be recombined. At this time, a specific wavelength of light is generated in the emission layer 150 by the movement and diffusion of the excitons.

Here, a part of the wavelength of the light is radiated to the outside by the third conductive layer of the semi-transmissive metal thin film, and a part of the light is radiated to the inside by the first conductive layer 120 which is the reflective metal thin film through the piezoelectric thin film 130. The reflection process is repeated. In this case, it is possible to control the emission color of the OLED by using the microcavity effect of allowing only specific wavelengths to exit by the reflective top layer and the element length of the OLED element. That is, the color of the emitted light is changed by changing the wavelength of light according to the thickness change of the piezoelectric thin film 130.

The wavelength of the LED of the LED according to the thickness change of the piezoelectric thin film 130 is changed according to the intensity of the first variable battery 170. When the thickness of the piezoelectric thin film increases, the short wavelength of the blue system is the third conductive layer. When emitted to the outside and the thickness of the piezoelectric thin film is reduced, the long wavelength of the red system is emitted to the outside of the third conductive layer 160.

The electrical signal according to an embodiment of the present invention is used as an AC voltage or a digital clock, and the strength of the electrical signal is controlled by a duty ratio or frequency of a clock cycle.

That is, the thickness of the piezoelectric thin film 130 is changed according to the intensity of the electrical signal. The wavelength of light is changed according to the thickness of the piezoelectric thin film, so that the emission color can be controlled.

With reference to FIG. 2, an ODL capable of color control using a piezoelectric thin film according to a second embodiment of the present invention will be described.

2 is a cross-sectional view of a bottom light emitting structure of OLED capable of color control using a piezoelectric thin film according to a second exemplary embodiment of the present invention.

As shown in FIG. 2, the lower light emitting structure 200 of the color LED controllable using the piezoelectric thin film includes a substrate 210, a first conductive layer 220, a piezoelectric thin film 230, and a second conductive layer. 240, the light emitting layer 250 and the third conductive layer 260 are sequentially deposited, and include the second variable battery 270 and the second battery 280.

The substrate 210 serves as a base of a transparent glass material. In the present embodiment, the material of the substrate is set to glass, but the present invention is not limited thereto. In addition, the substrate may be set to a transparent plastic or film.

In addition, the first conductive layer 220 is a semi-transmissive metal thin film, which is deposited on the substrate 210 and connected to the anode of the second variable battery 270.

In addition, the piezoelectric thin film 230 is a piezoelectric ceramic (PZT) material, and is deposited on the first conductive layer, and when the electrical signal is applied through the second variable battery 270, the thickness thereof is an electrical signal. Compared to the thickness when not applied, 8 to 12%, preferably 10% increase and decrease the thickness is changed.

In this embodiment, the material of the piezoelectric thin film is set to a piezoelectric ceramic (PZT) material, but the present invention is not limited thereto, in addition to transparent ceramic (PLZT), zinc oxide (ZnO), or aluminum nitride (AIN). It is also possible to set).

In addition, the second conductive layer 240 is a transparent conductor having a low work function, is deposited on the piezoelectric thin film 230, and is grounded to the cathodes of the second variable battery 270 and the second battery 280. . In this case, the transparent conductor having a low work function performs a function of drawing an electron by receiving an electrical signal.

In addition, the emission layer 250 is deposited on the second conductive layer 240, and electrons of the second conductive layer 240 by the second battery and holes of the third conductive layer 260 are recombined to excite excitons. And a specific wavelength of light by the formed excitons.

In addition, the third conductive layer 260 is a reflective metal thin film, which is deposited on the light emitting layer 250, is connected to the anode of the second battery 280, and functions to reflect the wavelength of light therein. .

In addition, the second variable battery 270 is connected to the second conductive layer 240 by a negative electrode, the positive electrode is connected to the third conductive layer 260, and the piezoelectric thin film by varying the intensity of the electrical signal. The thickness of 230 is adjusted.

In addition, the second battery 280 has a positive electrode connected to the third conductive layer 260 to inject holes, and a negative electrode is connected to the negative electrode of the second conductive layer 240 and the second variable battery 270. Connected to ground to inject electrons.

Referring to the color control process of the color LED control using the piezoelectric thin film according to the second embodiment of the present invention having the above-described configuration as follows.

The second conductive layer 240 is applied to the cathode by the second battery 280, and the third conductive layer 260 is applied to the anode by the second battery 280. At this time, electrons of the second conductive layer 240 and holes of the third conductive layer 260 move to the light emitting layer 250 to be recombined to form excitons. At this time, a specific wavelength of light is generated in the emission layer 250 by the movement and diffusion of the excitons.

Here, a part of the wavelength of the light is reflected inside by the third conductive layer 260 of the reflective metal thin film, the wavelength of the light is changed according to the thickness of the piezoelectric thin film 230, the semi-transmissive metal thin film The first part of the conductive layer 220 is radiated to the outside, the part is reflected back to the inside is repeated. In this case, the color of the emitted light is changed by changing the wavelength of the light according to the thickness change of the piezoelectric thin film 230.

The wavelength of light of the LEDs according to the thickness change of the piezoelectric thin film 230 is changed according to the intensity of the second variable battery 270. When the thickness of the piezoelectric thin film increases, the short wavelength of the blue system becomes the first conductive layer. When it is emitted to the outside and the thickness of the piezoelectric thin film is reduced, the long wavelength of the red system is emitted to the outside of the first conductive layer 220.

The electrical signal according to an embodiment of the present invention is used as an AC voltage or a digital clock, and the strength of the electrical signal is controlled by a duty ratio or frequency of a clock cycle.

At this time, the thickness of the piezoelectric thin film 230 is changed according to the strength of the electrical signal, the wavelength of light is changed according to the thickness of the piezoelectric thin film 230, it is possible to control the emission color.

As described above and described with reference to a preferred embodiment for illustrating the technical idea of the present invention, the present invention is not limited to the configuration and operation as shown and described as described above, it is a deviation from the scope of the technical idea It will be understood by those skilled in the art that many modifications and variations can be made to the invention without departing from the scope of the invention. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

According to the present invention as described above, when an electric signal is applied to the inside of the LED element by using the color of the light emitting color changes according to the thickness of the inner layer of the LED element inserts a piezoelectric thin film whose thickness is controlled and the electric signal It is effective to control the light emission color by applying to the element and adjusting the thickness of the piezoelectric thin film.

Claims (12)

In the LED which can control the color using the piezoelectric thin film, Substrate 110; A first conductive layer 120 deposited on the substrate and connected to an anode of a first variable battery, which will be described later; A piezoelectric thin film 130 made of a transparent ceramic (PLZT) material deposited on the first conductive layer, the thickness of which is increased or decreased as the electrical signal intensity of the first variable battery increases or decreases; A second conductive layer 140 deposited on the piezoelectric thin film and connected to a ground of the first variable battery and the negative electrode of the first battery; A light emitting layer deposited on the second conductive layer, the electrons of the second conductive layer by the first battery and the holes of the third conductive layer are recombined to form excitons, and the light emitting layer having a specific wavelength of light generated by the formed excitons ( 150); A third conductive layer 160 deposited on the light emitting layer and connected to the anode of the first battery; A first variable battery 170 connected to the first conductive layer and the second conductive layer to control the thickness of the piezoelectric thin film by an electrical signal; And A first battery 180 connected to the second conductive layer and the third conductive layer to inject electrons and holes into the light emitting layer; Including; The first conductive layer 120 is a reflective metal thin film and reflects the wavelength of light generated in the light emitting layer 150 therein, The second conductive layer 140 is a transparent conductor having a low work function, The third conductive layer 160 is a semi-transmissive metal thin film, and emits a part of the wavelength of light generated from the light emitting layer 150 to the outside, and reflects the part to the inside color control using a piezoelectric thin film. Available Oel ID. delete The method of claim 1, The piezoelectric thin film 130, When the electrical signal is applied through the first variable battery 170, the thickness of the piezoelectric thin film, characterized in that the thickness has a rate of change of 8 to 12% compared to the thickness when the electrical signal is not applied OEL ID that can control color by using. delete delete delete In the LED which can control the color using the piezoelectric thin film, Transparent glass substrate 210; A first conductive layer 220 deposited on the glass substrate and connected to the anode of the second variable battery; A piezoelectric thin film 230 made of a transparent ceramic (PLZT) material deposited on the first conductive layer, the thickness of which is increased or decreased as the electrical signal intensity of the second variable battery is increased or decreased; A second conductive layer 240 deposited on the piezoelectric thin film and connected to a ground of a cathode of the second variable battery and the second battery; A light emitting layer 250 which is deposited on the second conductive layer, wherein electrons of the second conductive layer and holes of the third conductive layer are recombined to form excitons, and a specific wavelength of light is generated by the formed excitons; A third conductive layer 260 deposited on the light emitting layer and connected to the anode of the second battery; A second variable battery 270 connected to the first conductive layer and the second conductive layer to control the thickness of the piezoelectric thin film by an electrical signal; And A second battery 280 connected to the second conductive layer and the third conductive layer to inject electrons and holes into the light emitting layer; Including; The first conductive layer 220 is a semi-transmissive metal thin film, and emits a portion of the wavelength of the light emitted from the light emitting layer 250 to the outside, and reflects the portion to the inside, The second conductive layer 240 is a transparent conductor having a low work function, The third conductive layer 260 is a reflective metal thin film, and color can be controlled using a piezoelectric thin film, characterized in that to reflect the wavelength of light generated in the light emitting layer 250 to the inside. delete The method of claim 7, wherein The piezoelectric thin film 230, When the electrical signal is applied through the first variable battery 270, the thickness of the piezoelectric thin film, characterized in that the thickness has a rate of change of 8 to 12% compared to the thickness when the electrical signal is not applied OEL ID that can control color by using. delete delete delete

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