KR100623222B1 - Organic Electro Luminescence Mode and Reflective Type Liquid Crystal Mode having Display Device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in which an organic light emitting mode and a reflective liquid crystal mode are combined, and includes a first substrate, a first electrode formed on an upper surface of the first substrate, to which a voltage is applied, and an upper surface of the first electrode. A light emitting layer formed on the light emitting layer, a second electrode formed on an upper surface of the light emitting layer and applied with a voltage and a current, a third electrode formed on an upper side of the second electrode and applied with a voltage, and an upper surface of the third electrode And a liquid crystal injected between the second substrate formed on the second substrate, at least one polarizing plate provided on the upper surface of the second substrate, and the first and second substrates.

By configuring as described above, by selectively driving according to the conditions of the external light, it is possible to always maintain a high contrast.

First and second substrates, first and second electrodes, light emitting layer, liquid crystal

Description

Organic Electro Luminescence Mode and Reflective Type Liquid Crystal Mode having Display Device}

1 is a cross-sectional view of a general organic light emitting device;

2 is a view showing the configuration of a conventional organic light emitting device;

3 is a diagram illustrating a configuration of a display device in which an organic light emitting mode and a reflective liquid crystal mode are combined according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100: display element 110: first substrate

121: first electrode 122: light emitting layer

123: second electrode 141: third electrode

143: polarizing plate 144: second substrate

L: liquid crystal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and in particular, an organic light emitting display that maintains a good contrast at all times regardless of the surrounding brightness by implementing the organic light emitting mode and the reflective liquid crystal mode in combination to drive the light in response to the surrounding brightness. A display device in which a mode and a reflective liquid crystal mode are combined.

In general, Electro-Luminescence (EL) means that electrons and holes form electron-hole pairs in a semiconductor or carriers are excited to a higher energy state. Light is generated by falling back to their equilibrium state, which is a stabilized state. This phenomenon is called EL.

1 is a cross-sectional view of a general EL device using the above-described EL phenomenon, and is a cross-sectional view showing an organic EL (Electro-Luminescence) using a semiconductor layer in which electrons and holes are formed as an organic material.

In the stacked structure of the organic EL device 10, an anode 13 is formed on the substrate 11 and the substrate 11, and a cathode 15 is formed on the anode 13. The light emitting layer 17 is formed between the cathode 15 and the anode 13.

The anode is made of a transparent material, the cathode is made of metal.

However, the above-described organic light emitting device has a problem that the external light is reflected through the cathode made of a metal, the contrast is reduced.

Conventionally, in order to solve the above-described problem, as shown in FIG. 2, a polarizing plate 18 and a λ / 4 phase difference plate 19 are attached to the surface of the substrate 11 so that external light enters the inside of the device, thereby providing the cathode 15. After the reflection, the phase difference is induced by the λ / 4 phase difference plate 19 so that it does not come out of the exterior and causes extinction interference.

That is, when only a specific wavelength (for example, a horizontal wave) passes through the polarizing plate 18, the horizontal wave passed therethrough is phase-shifted by the λ / 4 phase difference plate 19 and reflected by the cathode 15 surface.

At this time, the vertical wave reflected by the phase is changed and disappears without passing through the polarizing plate 18 passing only the horizontal wave.

The organic light emitting device configured as described above has an effect of blocking incident external light, but has a disadvantage in that the organic light emitting device reduces the transmittance of the polarizing plate having the luminance emitted by the organic light emitting device.

In addition, when the brightness of the external light is high, the power consumption increases when the brightness of the device is increased to improve visibility.

The present invention has been made to solve the above-mentioned problems, by implementing the organic light emitting mode and the reflective liquid crystal mode in combination to allow the device to change the mode according to the brightness of the surroundings, regardless of the brightness of the surroundings An object is to provide an organic light emitting device that always maintains good contrast.

In order to achieve the above object, the present invention provides a first substrate, a first electrode formed on the upper surface of the first substrate, a light emitting layer formed on the upper surface of the first electrode, and a second formed on the upper surface of the light emitting layer. An electrode, a third electrode formed on the upper side of the second electrode, a second substrate formed on the upper surface of the third electrode, at least one polarizing plate provided on the upper surface of the second substrate, and the first Characterized in that the liquid crystal injected between the two substrates.

Hereinafter, with reference to the accompanying drawings 3 will be described in more detail the configuration and operation of the present invention.

As shown in the drawing, the display device 100 according to the present invention is composed of an organic light emitting display unit which emits light and a reflective liquid crystal display unit which receives external light and displays information by arranging liquid crystals.

In more detail, a plurality of first electrodes 121 are formed in a stripe shape at predetermined intervals on an upper surface of the first substrate 110, and a light emitting layer 122 is formed on the upper surface of the first substrate 110. On the upper surface, a second electrode 123 is formed on a stripe while forming a direction orthogonal to the direction of the first electrode 121.

As described above, when the first electrode 121, the light emitting layer 122, and the second electrode 123 are stacked in this order to form the organic light emitting display 120, the third electrode 141 is formed on the upper surface of the sealant 131 through the sealant 131. The second substrate 144 having the polarizing plate 143 formed on the other end surface thereof is formed to maintain a predetermined distance from the first substrate 110, and between the first and second substrates 110 and 144. It consists of injecting liquid crystal (L).

The first electrode 121 is mainly used a metal such as Ca, Mg, Al, or an alloy thereof, and the deposition method is vacuum deposition, spin coating, inkjet printing, or dipping.

The second electrode and the third electrode 123, 141 is a transparent electrode material is used so that the light emitted from the light emitting layer 122 out of the device, indium tin oxide (ITO) is used a lot as the transparent electrode, the deposition method is In general, the sputtering method is applied.

In the liquid crystal L, its initial state (state where no voltage is applied) is such that the value due to the birefringence Δn and the thickness d has a λ / 4 phase difference value.

According to the present invention configured as described above, the driving mode is displayed differently according to the intensity of external light.

That is, when the indoor light is used in a room where the intensity of the external light is weak, the organic light emitting mode is driven, and a voltage is applied to the first electrode 121 and the second electrode 123, respectively, and the first electrode 121 and the first ( As the voltage is applied to the electrode, the emission layer 122 emits light to display information.

In this case, when external light is incident by the liquid crystal L having the birefringence Δn and the thickness d having a λ / 4 phase difference value, the light polarized through the polarizer 143 is the liquid crystal L ), The phase is changed, and the light whose phase is changed is reflected by the surface of the first electrode 121 which is a metal electrode. In this case, the reflected light does not pass through the polarizer 143 due to phase delay, thereby improving contrast.

On the other hand, when the reflection type liquid crystal mode is operated outdoors when the intensity of external light is strong and a voltage is applied to the second electrode 123 and the third electrode 141, the liquid crystal L between the electrodes changes in proportion to the voltage. The light of the light source introduced into the predetermined amount from the outside is passed through the liquid crystal layer and the amount is modulated and then reflected from the first electrode 121 to appear as the brightness of the screen.

In the above description, the driving state of the organic light emitting mode or the reflective liquid crystal mode is selectively driven by a controller (not shown).

For example, the amount of light is sensed so that the organic light emitting mode is driven when the amount of light is small and the reflective liquid crystal mode is driven when the amount of light is large.

In the above description, the sensing of the amount of light has been described as an example, but is not limited thereto.

As described above, the organic light emitting display mode which emits itself in response to the brightness of the surroundings and the reflective liquid crystal mode displaying the image by controlling the amount of light coming from the outside are configured in a complex manner so as to be selectively driven according to the conditions of the external light. This ensures good contrast at all times, regardless of the environment.

In other words, it combines the advantages of the organic light emitting device showing a good contrast with the darker ambient brightness and the reflection type liquid crystal mode showing a higher contrast with the brighter ambient light, the organic light emitting mode in the room with low external light Is driven to display information by self-emission of the light emitting layer 122. At this time, the liquid crystal acts as a λ / 4 phase difference plate to extinguish the incident external light, thereby preventing the contrast from being lowered.

By configuring to operate as described above to solve the disadvantage of the conventional organic light emitting device that had to increase the brightness of the device in order to improve visibility when the external light is bright to solve the increase in power consumption.

As described above, according to the present invention, the organic light emitting mode and the reflective liquid crystal mode are combined to implement a display device configured to be selectively driven according to external light conditions, thereby maintaining high contrast at all times regardless of ambient brightness. Can be.

In addition, when the organic light emitting mode is driven, the phase change of light incident from the outside is made to be a liquid crystal having a phase difference value of λ / 4, thereby improving the conventional structure using a separate phase difference film, thereby improving external light. In order to improve visibility, the disadvantage of power consumption increases as the brightness of the device is increased.

Claims (6)

A first substrate; A first electrode formed on an upper surface of the first substrate and to which a voltage and a current are applied; An emission layer formed on an upper surface of the first electrode to emit light by electric current; A second electrode formed on an upper surface of the light emitting layer and to which voltage and current are applied; A third electrode formed on the second electrode and to which a voltage is applied; A second substrate formed on the upper surface of the third electrode; At least one polarizing plate formed on an upper surface of the second substrate; A liquid crystal injected between the first and second substrates, Wherein the liquid crystal is arranged such that the product of birefringence and thickness in the initial state where no voltage is applied has a λ / 4 retardation value. The method of claim 1, The first electrode is a display device combined organic light emitting mode and reflective liquid crystal mode, characterized in that the metal. The method of claim 1, And the second electrode and the third electrode are formed of a transparent electrode material that transmits light. The method of claim 1, The second substrate is a display element combined with an organic light emitting mode and a reflective liquid crystal mode, characterized in that the transparent material which transmits light. delete The method of claim 1, The organic light emitting mode is characterized in that the voltage is applied to the first and second electrodes by the intensity of the external light to drive the reflective liquid crystal mode or the voltage is applied to the second and third electrodes to drive the organic light emitting mode. And a display device in which a reflective liquid crystal mode is combined.

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