KR20080000762A - Dual display apparatus - Google Patents

Abstract

A bidirectional display device is provided to supply light to a display panel in a plane type using a light supply panel having a light emitting element no need of light guiding plate, thereby suppressing the deterioration of picture quality due to presence of the light guiding plate. A bidirectional display device comprises a light emitting unit(800) and a display panel(400). The light emitting unit includes a first substrate(500), a second substrate(600) disposed above the first substrate, and a light emitting element(700) formed between the first substrate and the second substrate. The display panel includes a third substrate(100) disposed above the light emitting unit, a fourth substrate(200) disposed above the third substrate, and a liquid crystal layer(300) interposed between the third substrate and the fourth substrate. The display panel has a transmittance area(TA) overlapping the light emitting element and a reflection area(RA) hardly overlapping the light emitting element.

Description

Interactive display device {DUAL DISPLAY APPARATUS}

1 is a conceptual diagram illustrating a bidirectional display device according to an exemplary embodiment of the present invention.

2 is a plan view illustrating a bidirectional display device according to an exemplary embodiment of the present invention on a display panel.

3 is a cross-sectional view taken along line II ′ of FIG. 2.

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

100: first substrate 200: second substrate

300: liquid crystal layer 400: display panel

500: third substrate 600: fourth substrate

700: light emitting element 710: first electrode

720: organic light emitting layer 730: second electrode

800: light emitting unit 900: bidirectional display device

TA: transmission region RA: reflection region

TP: Transmissive Pixel RP: Reflective Pixel

PE: pixel electrode RL: reflective film

The present invention relates to a bidirectional display device, and more particularly, to a bidirectional display device employing a display panel having a liquid crystal display panel and a light emitting element.

In general, liquid crystal displays are thin and light, and have advantages of low driving voltage and low power consumption. Such liquid crystal displays generally display images in only one direction. Recently, however, a two-way liquid crystal display device has been developed that displays the same image or different images in both directions, instead of displaying the image in only one direction.

The bidirectional liquid crystal display device uses a display module composed of two light units and two display panels to display images in both directions, and a display module composed of one light unit and two display panels. A two-way type for displaying images in both directions, and one light unit and one display panel, wherein the one display panel includes a transmissive region and a reflective region for transflective display of images in both directions. Types and the like.

The transflective type includes, for example, a light unit, a light guide plate disposed on the light unit side, and a display panel disposed on the light guide plate. In this case, a prism pattern for effectively providing the light emitted from the light unit to the display panel is formed on the lower surface of the light guide plate. The first image is displayed in the first direction of the display panel using the light provided through the light guide plate. In the second direction opposite to the first direction, the second image is displayed using light reflected from the display panel in the second direction. In this case, since the reflected light is scattered by the prism pattern of the light guide plate, there are disadvantages in that the viewing angle characteristic of the second image is lowered and the image is blurred by the scattered light.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an interactive display device for improving display quality.

In order to realize the above object of the present invention, the bidirectional display device includes a light emitting unit and a display panel. The light emitting unit includes a first substrate, a second substrate disposed on the first substrate, and a light emitting device provided in a partial region between the first substrate and the second substrate. The display panel includes a third substrate disposed on the light emitting unit, a fourth substrate disposed on the third substrate, and a liquid crystal layer interposed between the third substrate and the fourth substrate, and overlaps the light emitting element. The transmissive region and the reflective region not overlapped with the light emitting element are defined.

According to the bidirectional display device, the image quality can be improved as compared to the bidirectional display device using optical conditions such as the light guide plate and the prism pattern under the light guide plate.

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

1 is a conceptual diagram illustrating an interactive display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the bidirectional display device 900 includes a display panel 400 and a light emitting unit 800 disposed on a rear surface of the display panel 400.

The display panel 400 includes a first substrate 100, a second substrate 200, and a liquid crystal layer 300 interposed between the first substrate 100 and the second substrate 200. That is, the display panel 400 is a liquid crystal display panel.

The first substrate 100 is a thin film transistor substrate on which driving elements such as signal wires and thin film transistors are formed, and the second substrate 200 is a color filter substrate on which a color filter layer for expressing color is formed.

The display panel 400 includes a transmission area TA through which light provided from the light emitting unit 800 is transmitted and a reflection area RA through which light provided from the light emitting unit 800 is reflected.

Preferably, the transmission area TA and the reflection area RA are alternately disposed. A reflective film RL for reflecting the light is formed on the first substrate 100 corresponding to the reflective area RA.

The light emitting unit 800 includes a third substrate 500, a fourth substrate 600, and a plurality of light emitting elements 700 provided between the third substrate 500 and the fourth substrate 600.

The third substrate 500 and the fourth substrate 600 are transparent substrates that transmit light. The light emitting unit 800 provides the light generated by the light emitting element 700 to the display panel 400.

The light emitting element 700 is disposed in the light emitting unit 800 corresponding to the transmission area TA. The light emitting device 700 is formed of a surface light emitting device. For example, the light emitting device 700 may be formed of an organic light emitting diode. Meanwhile, it is preferable that nothing is formed in the light emitting unit 800 corresponding to the reflective region RA.

The light emitted from the light emitting device 700 passes through the third substrate 500 and is emitted toward the display panel 400, and is not emitted toward the fourth substrate 600. Therefore, the non-display portion NDPA is defined in the second display panel 800 corresponding to the transmission area TA of the display panel 400.

A portion of the light provided from the light emitting element 700 to the display panel 400 is emitted in the first direction through the transmission area TA. Accordingly, a first image is displayed on the first substrate 100.

Meanwhile, some of the light provided from the light emitting element 700 to the display panel 400 is provided to the reflective area RA. Light provided to the reflective region RA is reflected by the reflective film RL and is emitted in a second direction opposite to the first direction. Accordingly, the second image is displayed on the second substrate 200.

In this case, since the third and fourth substrates 500 and 600 of the light emitting unit 800 are transparent substrates and nothing is formed in the light emitting unit 800 corresponding to the reflective area RA, the second image may be a third image. And fourth substrates 500 and 600. That is, the display unit DPA is defined on the light emitting unit 100 corresponding to the reflective area RA.

 2 is a plan view illustrating a bidirectional display device of the present invention on a display panel, and FIG. 3 is a cross-sectional view taken along the line II ′ of FIG. 2.

Hereinafter, the present invention will be described in more detail with reference to FIGS. 2 to 3.

Referring to FIG. 2, the display panel 400 includes a transmission pixel TP formed corresponding to the transmission area TA of FIG. 1 and a reflection pixel RP formed corresponding to the reflection area RA. Alternatively, the display panel 400 may be formed such that both the transmission area TA and the reflection area RA are defined in one pixel.

However, in the present exemplary embodiment, the present invention will be described using an example of a display panel in which the transmission pixel TP corresponding to the transmission area TA and the reflection pixel RP corresponding to the reflection area RA are provided.

 The first substrate 100 formed of a thin film transistor substrate includes signal lines GL and DL, which define the transmission pixels TP and the reflection pixels RP, and the transmission pixels TP and the reflection pixels RP. And a thin film transistor (TFT) formed at each.

In detail, the first substrate 100 includes a first transparent substrate 110, gate lines GL, data lines DL, and thin film transistors TFT formed on the first transparent substrate 110. do.

The first transparent substrate 110 is made of a transparent material that can transmit light. For example, the transparent substrate 110 is made of glass.

The gate lines GL are formed on a surface of the transparent substrate 110 that faces the second substrate 200 and define upper and lower sides of the transparent pixels TP and the reflective pixels RP. .

The gate insulating layer 130 is formed on the gate lines GL. The gate insulating layer 130 is formed on the first transparent substrate 110 on which the gate lines GL are formed to cover the gate lines GL. The gate insulating layer 130 is formed of, for example, a silicon nitride film (SiNx) or a silicon oxide film (SiOx).

The data lines DL are formed on the gate insulating layer 130 and define left and right sides of the transmission pixels TP and the reflection pixels RP.

The thin film transistor TFT is connected to the gate line GL and the data line DL to be formed in the transmissive pixel TP and the reflective pixel RP. The thin film transistor TFT applies an image signal applied through the data line DL to the pixel electrode PE in response to a scan signal applied through the gate line GL.

The thin film transistor TFT includes a gate electrode G, an active layer A, a source electrode S, and a drain electrode D. FIG.

The gate electrode G is connected to the gate line GL and constitutes a gate terminal of the thin film transistor TFT.

The active layer A is formed on the gate insulating layer 130 corresponding to the gate electrode G. The active layer A includes a semiconductor layer 141 and an ohmic contact layer 142. The semiconductor layer 141 is made of, for example, amorphous silicon (a-Si). The ohmic contact layer 142 is made of, for example, amorphous silicon (hereinafter, n + a-Si) doped with a high concentration of n-type impurities.

The source electrode S is connected to the data line DL and is formed to extend to the upper portion of the active layer A. The source electrode S constitutes a source terminal of the thin film transistor TFT.

The drain electrode D is formed on the active layer A to be spaced apart from the source electrode S. FIG. The drain electrode D constitutes a drain terminal of the thin film transistor TFT. The drain electrode D is connected to the pixel electrode PE through the contact hole CH formed in the passivation layer 160 and the planarization layer 170.

The source electrode S and the drain electrode D are disposed on the active layer A to be spaced apart from each other to form a channel of the thin film transistor TFT.

The passivation layer 160 is formed on the gate insulating layer 130 on which the data lines DL and the thin film transistor TFT are formed to cover the data lines DL and the thin film transistor TFT. The protective film 160 is made of, for example, a silicon nitride film (SiNx) or a silicon oxide film (SiOx).

The planarization layer 170 is formed on the passivation layer 160. A contact hole CH is formed in the planarization layer 170 and the passivation layer 160 to expose the drain electrode D of the thin film transistor TFT.

Meanwhile, a micro lens pattern may be formed on the planarization layer 170 in order to increase the reflectance of the light reflected by the reflective pixel RP and to improve the viewing angle.

The pixel electrode PE is formed on the planarization film 170. The pixel electrode PE is formed on the planarization layer 170 corresponding to the transmission pixel TP and the reflection pixel RP, respectively. The pixel electrode PE is electrically connected to the drain electrode D through the contact hole CH formed in the planarization layer 170 and the passivation layer 160.

The pixel electrode PE is made of a transparent conductive material through which light can pass. For example, the pixel electrode PE is formed of indium zinc oxide (IZO) or indium tin oxide (ITO).

The display panel 400 further includes a reflective film RL for reflecting light supplied from the light emitting unit 800. The reflective film RL is formed on the pixel electrode PE corresponding to the reflective pixel RP. The reflective film RL is made of a conductive material having high light reflectance to reflect light. In the exemplary embodiment of the present invention, the reflective film RL is stacked on the pixel electrode PE, but the pixel electrode PE formed on the reflective pixel RP is formed of a conductive material having a high light reflectance. The electrode PE itself can also be used as the reflective film.

The second substrate 200 made of the color filter substrate includes a color filter layer 220 for expressing color.

In detail, the second substrate 200 includes a second transparent substrate 210, a color filter layer 220 formed on the second transparent substrate 210, and a common electrode 230.

The second transparent substrate 210 is made of a transparent material through which light can be transmitted. For example, the second transparent substrate 210 is made of glass.

The color filter layer 220 is formed on a surface of the second transparent substrate 210 that faces the first substrate 100. The color filter layer 220 includes color filters such as red (R), green (G), and blue (B) to implement color.

The common electrode 230 is formed on the color filter layer 220 to face the first substrate 100. The common electrode 230 is made of a transparent conductive material to transmit light. For example, the common electrode 230 is made of indium zinc oxide (IZO) or indium tin oxide (ITO).

The liquid crystal layer 300 disposed between the first substrate 100 and the second substrate 200 has a structure in which liquid crystals having optical and electrical characteristics such as anisotropic refractive index and anisotropic dielectric constant are arranged in a predetermined form. In the liquid crystal layer 300, an arrangement of liquid crystals is changed by an electric field formed between the pixel electrode PE and the common electrode 230, and the transmittance of light passing through the liquid crystal layer 300 is controlled according to the arrangement change of the liquid crystals.

 Although not shown, the display panel 400 further includes a driving chip mounted on the first substrate 100. The driving chip drives the display panel 400 to display the first image and the second image in response to a control signal applied to the outside.

The display panel 400 having the above configuration displays the first image in the direction of the first substrate 100 using the light provided from the light emitting unit 800 and transmitted through the transmission pixel TP. In addition, the display panel 400 is provided from the light emitting unit 800 and displays a second image in the direction of the second substrate 200 by using light reflected by the reflective film RL. However, since nothing is formed in the light emitting unit 800 corresponding to the reflective pixel RP, the second image passes through the third substrate 500 and the fourth substrate 600 which are transparent substrates. On the fourth substrate 600.

That is, although the light emitting unit 800 does not display an image by directly driving the pixel, the light emitting unit 800 may perform both a function of providing a light to the display panel 400 and a function of displaying a second image. In this case, since the second image uses the light reflected from the reflective film RL, the display quality is lower than that of the first image. Therefore, in the bidirectional display device 900 of the present invention, it is preferable that the first image is a main image.

On the other hand, in the bidirectional display device 900 according to the present invention, since the light emitting unit 800 emits surface light, a light guide plate for guiding a separate lamp and light provided from the lamp toward the display panel 400 is unnecessary. . Therefore, in the conventional bidirectional display device, it is possible to prevent the display quality deterioration caused by the second image due to the prism pattern formed under the light guide plate.

Meanwhile, signal wires for driving the light emitting device 700 are formed on any one of the third and fourth substrates 500 and 600. The light emitting device 700 is a surface light emitting device, and for example, may be formed of an organic light emitting device. The light emitting device 700 may be an active matrix type driven by a thin film transistor for each pixel and a passive matrix type without the thin film transistor.

When the light emitting device 700 is formed in an active matrix manner, a thin film transistor connected to the signal lines is formed on the third substrate or the fourth substrate.

The light emitting device 700 includes, for example, a first electrode 710, an organic emission layer 720, and a second electrode 730.

The first electrode 710, the organic emission layer 720, and the second electrode 730 are sequentially formed from the fourth substrate 600 in the direction of the third substrate 500.

The first electrode 710 reflects light and is formed of a metal material having excellent conductivity. The second electrode 730 is formed of a conductive material made of a transparent material that can transmit light.

Each of the first electrode 710 and the second electrode 730 functions as a cathode and an anode of the light emitting device. The second electrode 730 may function as an anode, and the first electrode 710 may function as a cathode. When voltage is applied to the cathode and the anode, electrons of the cathode and holes of the anode are injected into the organic emission layer 720. The electrons and holes combine in the organic emission layer 720 to form an exciton, and the exciton falls to a ground state to generate light.

Accordingly, light emitted from the organic emission layer 720 is emitted toward the display panel 400 through the second electrode 730 which is a transparent electrode. In this case, since the first electrode 710 reflects light, no light is emitted toward the fourth substrate 600.

In the present invention, as in the bidirectional display device using a separate lamp on the side of the display panel, optical conditions such as the formation of a prism pattern on the light guide plate are not used. have.

As described above, the light guide plate for guiding the light can be omitted by providing light to the display panel in a planar manner using a light supply panel including a light emitting element. Therefore, the image quality can be improved compared to the conventional bidirectional display device using optical conditions such as the light guide plate and the prism pattern under the light guide plate.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (10)

A light emitting unit including a first substrate, a second substrate disposed on the first substrate, and a light emitting element provided in a partial region between the first substrate and the second substrate; And A transmissive region including a third substrate disposed on the light emitting unit, a fourth substrate disposed on the third substrate, and a liquid crystal layer interposed between the third substrate and the fourth substrate, and overlapping the light emitting element; And a display panel in which a reflective region overlapping the light emitting element is defined. The bidirectional display device according to claim 1, wherein the light emitting element is a surface light emitting element. The bidirectional display device of claim 2, wherein the light emitting device comprises a reflective electrode, an organic light emitting layer, and a transparent electrode sequentially stacked on the first substrate. The bidirectional display device of claim 1, wherein the display panel displays the first image in the direction of the fourth substrate using light provided in the transmission area. The bidirectional display device of claim 4, wherein the display panel displays a second image in the direction of the third substrate by using light provided in the reflection area. The method of claim 1, wherein the fourth substrate Signal wires defining a plurality of pixels; Thin film transistors formed in the pixels; And And a pixel electrode electrically connected to the thin film transistor. The bidirectional display device of claim 6, wherein the transmission area and the reflection area are defined in each pixel. The bidirectional display device as claimed in claim 6, wherein the plurality of pixels include a transmission pixel corresponding to the transmission area and a reflection pixel corresponding to the reflection area. The bidirectional display device of claim 1, wherein the fourth substrate comprises a reflective film formed corresponding to the reflective region. The method of claim 1, wherein the third substrate Color filter layers; And And a common electrode formed on the color filter layer.

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