KR20090110174A - Display device and method of operating the same - Google Patents

Abstract

PURPOSE: A display device and a method of operating the same are provided to reduce the power consumption of a hybrid display device. CONSTITUTION: A display device includes reflective first and second displays. The second display is prepared on the first display. In addition, the second display includes an oxide transistor having an oxide layer as a channel layer, wherein the oxide layer has an energy bandgap which is over 3.0eV. The first display is one of display, ECD, MEMS display and reflective LCD that uses an electronic ink(150).

Description

Display device and method of operating the same

The present invention relates to an electronic device, and more particularly, to a display device and an operation method thereof.

The biggest problem of mobile devices such as notebook computers, cell phones and personal digital assistants is the capacity of the battery. The usable time of a battery once charged is also an important measure of the value of a mobile device. Therefore, technologies for reducing the power consumption of mobile devices and increasing the capacity of batteries have been studied in various fields.

The most power-consuming part of mobile devices is the display. In notebook computers, about 70% of the power is dissipated in the display. In the case of liquid crystal displays (LCDs), which are typical displays used in non-mobile devices as well as mobile devices, the backlight should always be turned on while the LCD is operating. In the case of another type of organic light emitting display (OLED), it is necessary to continuously supply current to the organic light emitting device for image display. When viewing still images as well as watching videos, the backlight of the LCD must be turned on continuously, and the organic light emitting diode of the OLED must be continuously supplied. Therefore, such displays are a great cause of power consumption of mobile devices.

The present invention provides a hybrid display device and a method of operating the same that can reduce power consumption.

One embodiment of the invention the reflective first display; And a transparent second display provided on the first display, the second display including an oxide transistor having an oxide layer having an energy bandgap of 3.0 eV or more as a channel layer as a channel layer. do.

The first display may be one of a display using an e-ink, an electrochromic display (ECD), a micro-electro-mechanical systems (MEMS) display, and a liquid crystal display (LCD).

The second display may be a self-luminous type.

The second display may be an organic light emitting display (OLED).

The material constituting the second display may have a visible light transmittance of 70% or more.

The channel layer may be a ZnO-based material layer.

The hybrid display device of the present exemplary embodiment may include switching means for switching from the operation mode of the first display to the operation mode of the second display, or vice versa.

Another embodiment of the present invention is a transparent second display including a reflective first display and an oxide transistor having a channel layer having an oxide band having an energy bandgap of 3.0 eV or more, which is provided on the first display. A method of operating a hybrid display device including a display device, the display device comprising turning on at least one of the first and second displays according to characteristics of an image to be implemented. It provides a method of operation.

The first display may be operated in a state in which the second display is turned off.

The entire display surface of the first display may be black, and after the entire display surface of the first display is black, the first display may be turned off.

After the step of turning off the first display, the second display may be operated by turning on the second display.

The black color portion of the second display may use the black color of the display surface of the first display.

The first display may be one of a display using an e-ink, an electrochromic display (ECD), a micro-electro-mechanical systems (MEMS) display, and a liquid crystal display (LCD).

The second display may be a self-luminous type.

The second display may be an organic light emitting display (OLED).

Hereinafter, a display apparatus and an operation method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The width and thickness of the layers or regions shown in the accompanying drawings are somewhat exaggerated for clarity. Like numbers refer to like elements throughout.

1 shows a display device according to an embodiment of the present invention.

Referring to FIG. 1, a transparent second display D2 is provided on the reflective first display D1. The first display D1 may be a display using an e-ink 150. In more detail, the first display D1 may include the electronic ink 150 between the first and second substrates 100 and 200 and the ones 100 and 200. A plurality of first electrode lines 10 may be provided on an upper surface of the first substrate 100, and a plurality of second electrode lines intersecting the first electrode lines 10 on the lower surface of the second substrate 200. 20 may be provided, and the electronic ink 150 may be provided between the first and second electrode lines 10 and 20. At least the second substrate 200 of the first and second substrates 100 and 200 may be a transparent substrate, for example, a glass substrate, and at least a second electrode line of the first and second electrode lines 10 and 20. 20 may be transparent. The electron ink 150 may include a plurality of capsules 15 having a diameter of about 100 to 200 μm, and each capsule 15 may have white particles 5a and black particles 5b. Light incident from the top of the capsules 15 may be reflected at the top surface of the capsules 15. Depending on the voltages applied to the first and second electrode lines 10 and 20, the positions of the white particles 5a and the black particles 5b in the capsule 15 may vary. For example, a negative voltage is applied to a predetermined first electrode line of the plurality of first electrode lines 10, and a positive (+) voltage is applied to a predetermined second electrode line of the plurality of second electrode lines 20. When the voltage is applied, the white particles 5a of the capsule 15 present at the intersections of the predetermined first and second electrode lines may be located close to the predetermined first electrode line, and the black particles 5b ) May be located close to the predetermined second electrode line. This means that the black particles 5b are disposed on the display surface of the first display D1. In this case, a pixel corresponding to the intersection of the predetermined first and second electrode lines may have a black color. On the contrary, when the white particles 5a are disposed close to the second electrode line 20, that is, when the white particles 5a are disposed on the display surface, the pixel may represent a white color. Even when the voltages applied to the predetermined first and second electrode lines are cut off, the positions of the white particles 5a and the black particles 5b may be maintained as they are. In addition, the first display D1 is a reflective display using external light and does not require a light source such as a backlight. Therefore, when a still image is implemented by using the first display D1 or when a document job that does not require high image quality is performed, power consumption can be minimized. In addition, the first display D1 may be used for a web search or reading an Internet document using the Internet. While the first display D1 is in use, the second display D2 may be in an off state. Since the second display D2 is transparent, the use of the first display D1 is not disturbed. Do not. In the present embodiment, a passive type display using an electronic ink (e-ink) is specifically disclosed as the first display D1, but the present invention is not limited thereto. The first display D1 may be used regardless of any structure as long as it is a reflective display using external light. For example, the first display D1 may be replaced with an electrochromic display (ECD), a micro-electro-mechanical systems (MEMS) display, or a reflective crystal display (LCD), and may be a passive type or an active type. ) May have a structure. Therefore, the first display D1 may be a display capable of implementing three or more colors, for example, full-color. In addition, the electrochromic display (ECD) will be briefly described. The electrochromic display (ECD) is a reflective display that changes the absorption wavelength of external light by using oxidation and reduction reactions of nickel oxide, tungsten oxide or organic matter. In other words, the state once changed can be maintained even if the current supply is interrupted. The configuration of the electrochromic display (ECD) is well known, and a detailed description thereof will be omitted. In addition, the principle and configuration of the MEMS display and reflective LCD are well known, and detailed description thereof will be omitted.

The second display D2 is for realizing a video or high quality screen, and may be a self-luminous display, for example, an organic light emitting display (OLED). As mentioned above, the second display D2 is preferably made of a transparent material because it should not interfere with the use of the first display D1. More specifically, the second display D2 is preferably made of materials having visible light transmittance of 70% or more. When the second display D2 is an OLED, the transistors used for driving and switching the OLED may be transparent oxide transistors having a transparent oxide layer as a channel layer. In this case, the transparent oxide layer may be an oxide layer having an energy bandgap of about 3.0 eV or more, for example, a ZnO-based oxide layer such as ZnO or GaInZnO (GIZO). Such an oxide layer not only exhibits relatively transparent characteristics to visible light, but also has a high charge mobility of about 30 cm ² / Vs. Therefore, when the oxide layer is applied to a channel layer, a transparent transistor having a fast reaction speed can be realized. Typical OLEDs mainly use an amorphous or polycrystalline silicon layer as a channel layer of a transistor. Since the amorphous or crystalline silicon layer is opaque, when these are used, it is difficult to secure the translucency of the transistor. However, since the transistor occupies a small area in the entire OLED, it is possible to manufacture a display with a certain degree of transparency even if the silicon layer is used as the channel layer. Therefore, in the embodiment of the present invention, the use of the silicon layer as the channel layer of the second display D1 may be a possible choice. However, in this case, the screen implemented by the first display D1 may appear somewhat blurred.

Meanwhile, a transparent conductive material such as InSnO (ITO), InZnO (IZO), and AlZnO (AZO) may be used as the conductive material of the second display D2, and a transparent insulating material such as a silicon insulating film may be used as the insulating material. Can be.

Although not shown in FIG. 1, switching means for switching from the operation mode of the first display D1 to the operation mode of the second display D2 or vice versa may be provided. The switching means is electrically connected to the first and second displays D1 and D2 and may have a toggle switch structure in which the handle is moved up and down. However, the structure of the switching means can be variously changed. For example, the operation mode may be switched using a function key rather than a toggle switch.

The manufacturing method of the display device of FIG. 1 will be briefly described as follows. One of the first display D1 and the second display D2 may be manufactured first, and then the other display may be manufactured thereon. In this case, a transparent insulating layer may be further formed between the first display D1 and the second display D2. For example, after the second display D2 is first manufactured on the glass substrate, a transparent insulating layer may be formed thereon, and the first display D1 may be manufactured on the transparent insulating layer. Alternatively, the first display D1 may be manufactured first, and then the second display D2 may be manufactured on the second substrate 200. Alternatively, a method of manufacturing the first display D1 and the second display D2 separately and then attaching the two D1 and D2 to each other is also possible. In this case, a transparent insulating layer may be further formed between the first display D1 and the second display D2, and the transparent insulating layer may have a function of an adhesive layer.

FIG. 2 illustrates a planar structure of a unit region of the second display D2 of FIG. 1.

2, a gate line GL1 is provided, and first and second data lines DL1 and DL2 perpendicular to the gate line GL1 are provided. The first transistor T1 may be provided at the intersection of the gate line GL1 and the first data line DL1, and the second transistor (T1) may be provided at the intersection of the gate line GL1 and the second data line DL2. T2) may be provided. The first transistor T1 may be a switching transistor, and the second transistor T2 may be a driving transistor. The first transistor T1 contacts the first gate electrode G1, the first channel layer C1 above the first gate electrode G1, and the first source electrode S1 in contact with both ends of the first channel layer C1. ) And the first drain electrode D1. The first gate electrode G1 may extend from the gate line GL1, and the first drain electrode D1 may extend from the first data line DL1. The second transistor T2 is the second source electrode S2 in contact with both ends of the second gate electrode G2, the second channel layer C2 above the second gate electrode G2, and the second channel layer C2. ) And a second drain electrode D2. The second drain electrode D2 may extend from the second data line DL2. The first source electrode S1 of the first transistor T1 may be electrically connected to the second gate electrode G2 of the second transistor T2 by the connection wiring CL1. Reference numeral CP1 denotes a first contact plug connecting the connection line CL1 and the first source electrode S1, and CP2 denotes a second contact plug connecting the connection line CL1 and the second gate electrode G2. Indicates. A light emitting unit LE1 electrically connected to the second transistor T2 may be provided in a pixel area between the first and second data lines DL1 and DL2. The light emitting unit LE1 may include a light emitting layer formed of an organic material, and may be connected to the second source electrode S2 of the second transistor T2 by the third contact plug CP3. A pixel region to be operated may be selected by the first transistor T1, and a current may be continuously supplied to the light emitting unit LE1 of the selected pixel region by the second transistor T2. Gate line GL1, first and second gate electrodes G1 and G2, first and second data lines DL1 and DL2, first and second source electrodes S1 and S2, and first and second The drain electrodes D1 and D2 and the connection wiring CL1 may be formed of a transparent conductive material such as ITO, IZO and AZO, and the first and second channel layers C1 and C2 may be formed of ZnO or GIZO. It may be formed of an oxide of the ZnO series.

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

Referring to FIG. 3, a first gate electrode G1 and a second gate electrode G2 are provided on the substrate SUB1. A gate insulating layer GI1 covering the first gate electrode G1 and the second gate electrode G2 is provided on the substrate SUB1. The gate insulating layer GI1 may be a transparent insulating layer, for example, a silicon oxide layer. The first channel layer C1 is provided on the gate insulating layer GI1 above the first gate electrode G1, and the first channel layer C1 contacts both ends of the first channel layer C1 on the gate insulating layer GI1. The source electrode S1 and the first drain electrode D1 are provided. The second data line DL2 is provided on the gate insulating layer GI1 spaced apart from the second gate electrode G2. An interlayer insulating layer ILD1 may be formed on the gate insulating layer GI1 to cover the first channel layer C1, the first source electrode S1, the first drain electrode D1, and the second data line DL2. Can be. The interlayer insulating layer ILD1 is a transparent insulating layer and may be a material layer similar to the gate insulating layer GI1. The first and second contact holes H1 and H2 exposing the first source electrode S1 and the second gate electrode G2 are provided in the interlayer insulating layer ILD1, and the first and second contact holes H1 are provided. , The first and second contact plugs CP1 and CP2 are provided in H2). The connection line CL1 connecting the first and second contact plugs CP1 and CP2 is provided on the interlayer insulating layer ILD1. Therefore, the first drain electrode D1 and the second gate electrode G2 are electrically connected to each other.

2 and 3 are merely examples of the structure of the second display D2 according to the embodiment of the present invention, and may be variously modified.

4 is a block diagram illustrating a method of operating a display apparatus according to an exemplary embodiment of the present invention. In this embodiment, the apparatus of FIG. 1 is used.

Referring to FIG. 4, the first display D1 may be operated as the first step s1. The first display D1 may be used to implement a still image, perform a document operation that does not require high image quality, perform a web search using the Internet, or read an Internet document. The second display D2 may be in an off state while the first display D1 is operated.

After the first step s1, the second step s2 may be performed to make the entire display surface of the first display D1 black. In FIG. 1, in order to make the entire display surface of the first display D1 black, a positive voltage is applied to the plurality of second electrode lines 20 and a negative voltage is applied to the plurality of first electrode lines 10. A negative voltage can be applied. The second step s2 may be a preliminary step for operating the second display D2. When operating the second display D2, when a black surface exists behind the second display D2, visibility of the second display D2 may be improved. However, the second step s2 is an optional step and may not be performed.

In a third step s3, the first display D1 is turned off. In this step, even if the supply of current to the first display D1 is stopped, the display surface of the first display D1 may remain black.

Subsequently, in operation S4, the second display D2 is turned on to operate. The second display D2 may implement a video or perform a task that requires a high quality screen. In particular, when a black color is to be implemented in a predetermined pixel (hereinafter, referred to as a first pixel) of the second display D2, the current may not be supplied to the first pixel. Then, the first pixel of the second display D2 is maintained in a transparent state so that a black color of the display surface of the first display D1 corresponding to the first pixel may appear through the first pixel. That is, if the color of the display surface of the first display D1 is black, it can be selectively used during the operation of the second display D2.

As a fifth step S5, the second display D2 may be turned off. Thereafter, the process may return to the first step s1 for operating the first display D1 or the fourth step s4 for operating the second display D2.

In the present embodiment, a case in which the first display D1 is operated first is described. However, the second display D2 may be operated before the first display D1. In some cases, the first display D1 may be operated. Part of and part of the second display (D2) can be operated at the same time.

As described above, according to the exemplary embodiment of the present invention, the still image or the low quality image is implemented by the first display D1 having low power consumption, and the moving image or high quality image is implemented by the second display D2. In this case, power consumption can be significantly reduced compared to a conventional display device that implements all images in LCD or OLED, and there is no problem in realizing a video or a high quality image.

5A and 5B show an example of use of a PDA to which a hybrid display device according to an embodiment of the present invention is applied. The PDA of FIGS. 5A and 5B functions not only as a video function but also as an e-book function.

FIG. 5A shows the usage mode of operating the reflective first display D1, that is, corresponding to the first step s1 of FIG. 4. For example, the usage mode of FIG. 5A may be an e-book mode.

FIG. 5B shows the usage mode of operating the second display D2, that is, corresponding to the fourth step s4 of FIG. 4. For example, the usage mode of FIG. 5B may be a video mode.

Hybrid display device according to an embodiment of the present invention can be applied to all electronic devices for the display, in particular, mobile computers such as notebook computers, mobile phones, PDAs, e-books, electronic dictionaries and MP3 players It can be applied to equipment. In this case, there is an advantage that the battery life of the mobile device can be extended by reducing power consumption.

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments, rather than to limit the scope of the invention. For example, those skilled in the art will appreciate that the components and structures of the display device of FIGS. 1 to 3 may be varied and modified, respectively. As a specific example, in FIG. 1, it will be appreciated that the second display D2 may be replaced with a device other than an OLED, for example, a transparent LCD. In addition, although it is described that the first display D1 mainly implements a still image, and the second display D2 mainly implements a video, in some cases, the first display D1 performs a video, and the second display. It will be appreciated that the display D2 may implement still images. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the technical spirit described in the claims.

1 is a cross-sectional view of a display device according to an embodiment of the present invention.

2 is a plan view of an OLED that may be included in a display device according to an embodiment of the present invention.

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

4 is a block diagram illustrating a method of operating a display apparatus according to an exemplary embodiment of the present invention.

5A and 5B show an example of use of a PDA to which a display device according to an embodiment of the present invention is applied.

* Explanation of Signs of Major Parts of Drawings *

5a: white particles 5b: black particles

10: first electrode line 15: the capsule of the electronic ink (e-ink)

20: second electrode line 100: first substrate

150: electronic ink 200: second substrate

C1, C2: channel layer CL1: connection wiring

CP1 to CP3: Contact plug D1, D2: Drain electrode

DL1, DL2: Data line H1, H2: Contact hole

G1, G2: gate electrode GL1: gate line

ILD1: interlayer insulation layer LE1: light emitting unit

S1, S2: source electrode SUB1: substrate

Claims (16)

Reflective first display; And And a transparent second display provided on the first display, the transparent second display including an oxide transistor having an oxide layer having an energy bandgap of 3.0 eV or more as a channel layer. 2. The method of claim 1, The first display is one of a display using an e-ink, an electrochromic display (ECD), a micro-electro-mechanical systems (MEMS) display, and a reflective crystal display (LCD). The method of claim 1, The second display is a self-luminous display device. The method of claim 3, wherein The second display is an organic light emitting display (OLED). The method according to any one of claims 1 to 4, Display material having a visible light transmittance of 70% or more of the material constituting the second display. The method of claim 1, The channel layer is a ZnO-based material layer. The method of claim 1, And switching means for switching from the operation mode of the first display to the operation mode of the second display, or vice versa. A hybrid comprising a reflective first display and a transparent second display having an oxide transistor as a channel layer on the first display, the oxide layer having an energy bandgap of 3.0 eV or more as a channel layer. In the operation method of the display device, And turning on at least one of the first and second displays according to a characteristic of an image to be implemented. The method of claim 8, And operating the first display while the second display is turned off. The method of claim 9, Making the entire display surface of the first display black. The method of claim 10, After making the entire display surface of the first display to black, Turning off the first display. The method of claim 11, After the step of turning off the first display, And operating the second display by turning on the second display. The method of claim 8 or 12, And a black color portion of the second display uses a black color of the display surface of the first display. The method of claim 8, The first display is one of a display using an electronic ink (e-ink), an electrochromic display (ECD), a micro-electro-mechanical systems (MEMS) display and a reflective crystal display (LCD). The method of claim 8, The second display is a self-luminous display device. The method of claim 15, The second display is an organic light emitting display (OLED).

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