KR100685940B1 - Display device and method for fabricating the same - Google Patents

Abstract

The present invention is to provide a display device and a manufacturing method capable of supplying a sufficient attraction force to the movable electrode even at a low drive voltage, the display device of the present invention, a plurality of light absorption layers formed on the substrate, and the light Manufacture of a display device according to the present invention, comprising a transparent conductive layer formed on the front surface of the substrate including absorbing layers, a plurality of movable electrodes formed on the upper side of the transparent conductive layer, and a backlight formed on the rear surface of the substrate. The method includes forming a plurality of light absorbing layers on a substrate, forming a light transmissive conductive layer on the front surface of the substrate including the light absorbing layers, forming a sacrificial layer on the light transmissive conductive layer, and Forming a plurality of movable electrodes on the sacrificial layer corresponding to each other; It characterized by including the process of removing.

Movable Electrode, Light Absorption Layer

Description

Display device and method for fabricating the same

1 is a plan view of a display device according to the prior art

2A and 2B are cross-sectional views taken along a line A-A 'of FIG. 1 to illustrate the arrangement of electrodes in a non-display state.

FIG. 2B is a cross-sectional view taken along line AA ′ of FIG. 1, showing a layout of electrodes in a display state.

FIG. 2C is a cross-sectional view taken along the line BB ′ of FIG. 1.

3 is a plan view of a display device according to a first embodiment of the present invention;

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

5A to 5E are cross-sectional views of a manufacturing process of the display device according to the first embodiment of the present invention.

6 is a plan view of a display device according to a second exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view taken along line AA ′ of FIG. 6.                 

8 is a plan view of a display apparatus according to a third embodiment of the present invention.

9 is a cross-sectional view taken along the line AA ′ of FIG. 8.

Explanation of symbols for main parts of the drawings

20: backlight 21: substrate

23a: light absorbing layer 25: light transmitting conductive layer

27: sacrificial layer 29: elastic material layer

31: movable electrode

The present invention relates to a display device, and more particularly, to a display device for displaying an image by modulating a light beam and a method of manufacturing the same.

As a next-generation display device, various flat panel displays (FPDs) are being actively researched. Among them, generalized display devices include liquid crystal displays (LCDs) using electro-optical characteristics of liquid crystals, and gases. And a plasma display panel (PDP) using discharge.

Among them, the liquid crystal display device (hereinafter, abbreviated as "LCD") has a narrow viewing angle, a slow response speed, and requires a thin film transistor (TFT) and an electrode using a semiconductor manufacturing process. Plasma display panel (PDP) has the advantage that the manufacturing process is simple and advantageous to large area, but the power consumption is high, and the discharge and luminous efficiency is low and expensive.

Development of a new display device that can solve the problems of such a flat panel display device is in progress.

Hereinafter, a display apparatus according to the related art will be described with reference to the accompanying drawings.

1 is a plan view of a display device according to the prior art.

As shown in FIG. 1, a plurality of fixed electrodes 13 formed side by side at a predetermined interval on the substrate 11 and at a corresponding portion between the fixed electrode 13 and the fixed electrode 13. It is composed of a plurality of movable electrodes 15 formed in the same direction as the direction of the fixed electrode 13, both ends in the longitudinal direction of the movable electrode 15 are both in the longitudinal direction of the fixed electrode 13 It has a structure extending beyond the end. In addition, both ends in the one direction of the movable electrode 15 has a structure overlapping with both ends in the one direction of the fixed electrode 13.

Accordingly, in a state where no voltage is applied between the fixed electrode 13 and the movable electrode 15, the movable electrode 15 is floated so that light projected from the backlight of the lower part of the substrate 11 is transmitted to the display surface. In this applied state, the movable electrode 15 is in contact with the fixed electrode 13 so that light of the backlight cannot be transmitted toward the display surface.

This will be described in detail with reference to the cross-sectional views shown in FIGS. 2A and 2B.

2A and 2B are cross-sectional views taken along the line AA ′ of FIG. 1, and the fixed electrodes 13 are formed on the substrate 11 side by side at predetermined intervals, and each of the fixed electrodes 13 is formed in response to a voltage signal. It consists of movable electrodes 15 overlapping both sides of the 13 parts. Herein, the fixed electrodes 13 are formed in a stripe shape on the substrate 11, and the movable electrodes 15 are fixed to the substrate 11 at both ends along the long direction thereof, and a central portion thereof is formed of the substrate ( 11) it is floated a predetermined interval and moved up and down by an electrical signal.

2A is a cross-sectional view showing an arrangement of electrodes in a non-display state. A predetermined level of voltage is applied to the fixed electrodes 13 and the movable electrodes 15. Thus, an attraction force due to electrostatic force acts between the fixed electrodes 13 and the movable electrodes 15 such that the movable electrodes 15 come into contact with the adjacent fixed electrode 13. At this time, the fixed electrodes 13 and the movable electrodes 15 block the light incident from the backlight 19 provided on the rear surface of the substrate 11 so that the display surface is displayed in black.

In contrast, in the display state, that is, as shown in FIG. 2B, no voltage is applied to the fixed electrodes 13 and the movable electrodes 15. Therefore, since the movable electrodes 15 are restored to their original state by their elastic restoring force, the movable electrodes 15 are lifted up from the substrate 11 and the fixed electrode 13. In this case, an optical path is formed between the fixed electrodes 13 and the movable electrodes 15, and light incident from the backlight 19 through the optical path is transmitted to the display surface and displayed as white. For reference, reference numeral “17” in FIGS. 2A to 2B indicates an elastic material layer.

2C is a cross-sectional view taken along the line BB ′ of FIG. 1, and it can be seen that the movable electrodes 15 are formed on the substrate 11 at regular intervals.

However, since the overlapping area between the fixed electrode and the movable electrode to which the voltage is applied is small, the conventional display device as described above has a problem that a very large driving voltage is required to give sufficient attraction force to move the movable electrode when the voltage is applied. .

The present invention has been made to solve the above problems of the prior art, and an object of the present invention is to provide a display device and a manufacturing method that can supply a sufficient attraction force to the movable electrode even at a low driving voltage.

The display device of the present invention for achieving the above object is a substrate, a plurality of light absorbing layers formed on the substrate, a light transmissive conductive layer formed on the substrate including the light absorbing layers and the light transmissive conductive layer It includes a plurality of movable electrodes formed on the upper side, and a backlight formed on the back of the substrate.

The light transmissive conductive layer may be formed in a stripe type or an island shape without being formed on the entire surface of the substrate.

The display device manufacturing method of the present invention comprises the steps of forming a plurality of light absorbing layers on the substrate, forming a light transmitting conductive layer on the entire surface including the light absorbing layer, and forming a sacrificial layer on the light transmitting conductive layer And forming a plurality of movable electrodes on the sacrificial layer corresponding to the light absorbing layers, and removing the sacrificial layer.

The display device of the present invention is characterized by forming a conductive material, such as a light transmissive conductive layer while being able to transmit light to the entire area or a specific area of the lower substrate in order to reduce the driving voltage.

That is, by forming a conductive material on the upper side of the light absorbing layer that can transmit the light incident from the backlight, when the voltage is applied between the material and the movable electrode, the area where the voltage is applied is increased so that the low driving voltage Under the circumstances, sufficient manpower could be supplied to the movable electrode.

Hereinafter, exemplary embodiments of the display device according to the present invention will be described with reference to the accompanying drawings.

First embodiment

3 is a plan view of a display device according to a first exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along line AA ′ of FIG. 3.

As shown in FIGS. 3 and 4, a substrate 21, a plurality of light absorbing layers 23a formed in one direction at predetermined intervals on the substrate 21, and the light absorbing layers 23a are included. Including a transparent conductive layer 25 formed on the front surface of the substrate 21 and a plurality of movable electrodes 31 formed on the upper side of the transparent conductive layer 25 corresponding to the adjacent light absorbing layer (23a) It is composed.

Here, each movable electrode 31 overlaps a predetermined portion of the light absorbing layer 23a adjacent thereto, and the movable electrode 31 is positioned above the light absorbing layer 23a based on the substrate 21. Both ends thereof constitute a microbridge.

An elastic material layer 29 is further provided below the movable electrode 31, and the light absorption layer 23a is preferably formed of an opaque material, and the elastic material layer 29 is an opaque material having good elastic properties. It is preferable to form. The light absorption layer 23a may be a conductive material or a non-conductive material.

In the display device of the present invention, the light-transmitting conductive layer 25 is formed on the entire surface of the substrate 21 including the light absorbing layer 23a, so that a sufficient attraction force is obtained even when the driving voltage for driving the movable electrode 31 is lowered. Since it is supplied, the driving voltage can be reduced.

Meanwhile, reference numeral 20 of FIG. 4 indicates a backlight.

When the display device is in a non-display state, since a predetermined voltage is applied between the transparent conductive layer 25 and the movable electrode 31, an attraction force due to electrostatic force is applied between the transparent conductive layer 25 and the movable electrode 31. In operation, the movable electrode 31 comes into contact with the transparent conductive layer 25. Therefore, since the light incident from the backlight 20 formed on the rear surface of the substrate 21 is not transmitted, the display surface is displayed in black. On the other hand, since no voltage is applied between the transparent conductive layer 25 and the movable electrode 31 in the display state, the elasticity of the movable electrode 31 is returned to the original state, so that the movable electrode 31 is transparent conductive. It emerges from layer 25 and maintains a predetermined spacing. Therefore, the light incident from the backlight 20 is transmitted to the display surface through the interval so that an image is displayed on the screen.

Thus, the method of manufacturing the display device according to the first embodiment of the present invention will be described with reference to FIGS. 5A to 5E.

As shown in FIG. 5A, a material layer 23 to be used as a light absorption layer is formed on the substrate 21, a photoresist (not shown) is applied on the material layer 23, and then exposed and developed. Pattern through process. Thereafter, the material layer 23 is selectively removed by an etching process using the patterned photoresist as a mask to form a plurality of light absorption layers 23a in one direction with a predetermined interval therebetween as shown in FIG. 5B. do.

Here, the material layer 23 to be used as the light absorption layer 23a may be any of a conductive material and a non-conductive material, and may be an opaque material.

As shown in FIG. 5C, after forming the transparent conductive layer 25 on the entire surface of the substrate 21 including the light absorbing layer 23a, the sacrificial layer 27 is formed on the transparent conductive layer 25. The sacrificial layer 27 is a material that is removed after the movable electrode is formed in a subsequent process, and typically, a silicon oxide film (SiO ₂ ), a photoresist, a spin on glass (SOG), and a polyimide ( Polyimide), Phosphorus Silicate Glass (PSG), Boro Phosphorus Silicate Glass (BPSG), and the like. Here, the material of the transparent conductive layer 25 includes, for example, indium tin oxide (ITO), zinc oxide (ZnO), and indium zinc oxide (IZO).

Subsequently, after the sacrificial layer 27 of the portion where the microbridges are to be formed is removed, an elastic material layer 29 is formed on the sacrificial layer 27 as shown in FIG. 5D. In this case, since the cross-sectional view taken along the line AA ′ of FIG. 4, the portion where the sacrificial layer 27 is removed does not appear. Subsequently, a conductive material layer is formed on the entire surface, a photoresist (not shown) is applied thereon, patterned by an exposure and development process, and the conductive material layer and elasticity are etched by using the patterned photoresist as a mask. The material layer 29 is selectively removed to form a plurality of movable electrodes 31 having the elastic material layer 29 formed thereon as shown in FIG. 5E. Finally, if only the sacrificial layer 27 is selectively removed, the display device manufacturing process according to the first embodiment of the present invention is completed.

The sacrificial layer 27 is removed by wet etching, and typically, may be removed with a hydrofluoric acid (HF) solution, or BHF (Buffered Dydrofluoric Acid) or Dilute HF may be used in addition to the hydrofluoric acid solution. In addition, when the sacrificial layer 27 is a photoresist, a stripper for photoresist may be used.

Second embodiment

In the above-described first embodiment of the present invention, a transparent conductive layer is formed on the front surface of the substrate including the fixed electrode in order to reduce the driving voltage. In the second embodiment of the present invention, the transparent conductive layer is partially formed.

As the light transmitting conductive layer is partially formed, the driving voltage tends to increase slightly compared to the first embodiment of the present invention, but the transmission efficiency is rather increased.

6 is a plan view of a display device according to a second exemplary embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along line AA ′ of FIG. 6.

6 and 7, the display device according to the second embodiment of the present invention includes a substrate 21 and a plurality of light absorption layers 23a formed in one direction at regular intervals on the substrate 21. And a plurality of light transmissive conductive layers 25 formed in a direction crossing the light absorbing layers 23a and having a predetermined interval therebetween, and formed at a portion corresponding to the adjacent light absorbing layers 23a, and adjacent light absorbing layers ( And a plurality of movable electrodes 31 overlapping a predetermined portion with 23a.

Here, each of the movable electrodes 31 overlaps a predetermined portion of the light absorbing layer 23a adjacent thereto, and the movable electrodes 31 are positioned above the light transmissive conductive layer 25 with respect to the substrate. Both ends thereof are connected to the substrate 21 to form a microbridge.

An elastic material layer 29 is further provided below the movable electrode 31a, and the light absorbing layer 23a is preferably formed of a conductive or non-conductive opaque material, and the elastic material layer 29 has elastic properties. It is desirable to form this good opaque material.

In this manner, it is possible to form the light transmissive conductive layer 25 partially without forming the entire surface of the substrate to increase the transmission efficiency.

Meanwhile, reference numeral 20 of FIG. 7 indicates a backlight.

Here, the transparent conductive layer 25 shown in FIG. 6 is formed in a stripe type across the light absorbing layer 23a, but is not limited to the stripe type, but is formed in a shape having a partial slope, It is possible to form an island shape.

The manufacturing method of the display device according to the second embodiment of the present invention configured as described above is almost similar to the manufacturing method of the first embodiment, except that the light-transmitting conductive layer 25 is formed on the entire surface of the substrate including the light absorption layer 23a. Since only a partial removal step is further added, a description thereof will be omitted below.

On the other hand, the width of the transparent conductive layer 25 is not necessarily constant, as shown in Figure 8 according to the third embodiment of the present invention, the interval between adjacent transparent conductive layers 25 is also not constant. You don't have to. For reference, FIG. 9 is a cross-sectional view taken along the line A-A 'of FIG. 8, and the line A-A' is cut around the portion where the light absorption layer 23a and the movable electrode 31 overlap.                     

Therefore, as shown in FIG. 9, a light-transmitting conductive layer 25 is formed on the light absorbing layer 23a and partially spaced apart from each other, and above the light-transmitting conductive layer 25. It can be seen that the movable electrode 31 is formed in the same direction as the light absorption layer 23a.

As described above, the display device of the present invention and the manufacturing method thereof have the following effects.

First, since the light transmissive conductive layer is formed on the front surface of the substrate including the light absorbing layer, it is possible to maximize the voltage application area between the movable electrodes, thereby providing sufficient manpower to the movable electrodes even at a low driving voltage.

Second, the light transmitting conductive layer may be partially formed to reduce the driving voltage and to prevent the transmission efficiency from decreasing.

Claims (16)

Board; A plurality of light absorption layers formed at predetermined intervals on the substrate; A light transmissive conductive layer formed on an entire surface of the substrate on which the light absorption layers are formed; A plurality of movable electrodes formed on an upper side of the light transmissive conductive layer so as to correspond to the light absorbing layer; And And a backlight formed on the back surface of the substrate. The display apparatus of claim 1, wherein the light transmissive conductive layer is any one of indium tin oxide (ITO), zinc oxide (ZnO), and indium zinc oxide (IZO). The display apparatus of claim 1, wherein the material of the light absorption layer comprises an opaque conductive or nonconductive material. The display apparatus of claim 1, wherein the light transmissive conductive layer is formed or partially formed on the front surface of the substrate. The display apparatus of claim 4, wherein the light transmissive conductive layer is formed in a stripe type across the light absorbing layer or in an island shape. The display apparatus of claim 4, wherein each of the plurality of transparent conductive layers has a different width. The display apparatus of claim 4, wherein the plurality of light transmissive conductive layers are different from each other. The display apparatus of claim 4, wherein both ends of the movable electrode are connected to the light transmissive conductive layer. Forming a plurality of light absorption layers on the substrate; Forming a light transmitting conductive layer on the substrate including the light absorption layers; Forming a sacrificial layer on the light transmissive conductive layer; Forming a plurality of movable electrodes on the sacrificial layer corresponding to the light absorbing layer; And removing the sacrificial layer. The method of claim 9, further comprising forming an elastic material layer under the movable electrodes. The method of claim 9, further comprising selectively removing the sacrificial layer of the portion where the microbridges are to be formed after the sacrificial layer is formed. The method of claim 9, wherein the forming of the movable electrode comprises: Removing the sacrificial layer to sequentially form an elastic material layer and a light absorption layer material layer on the entire surface including the exposed transparent conductive layer; And selectively removing the light absorbing material layer and the elastic material layer to form a plurality of movable electrodes at both ends thereof connected to the light transmissive conductive layer to form a microbridge. Manufacturing method. The method of claim 9, wherein the step of forming the light transmissive conductive layer, Forming a light-transmitting conductive material on the entire surface including the light absorption layers; And forming a plurality of light transmissive conductive layers in a direction crossing the light absorbing layers by selectively removing the light transmissive conductive material by an etching process using a mask. The method of claim 9, wherein the step of forming the light transmissive conductive layer, Forming a light-transmitting conductive material on the entire surface including the light absorption layers; And selectively removing the light transmissive conductive material to form a plurality of light transmissive conductive layers having an island shape on the light absorbing layers by an etching process using a mask. The method of claim 9, wherein the light transmissive conductive layer is formed on an entire surface of the substrate including the light absorbing layer. The method of claim 9, wherein the light transmissive conductive layer is formed of any one of indium tin oxide (ITO), zinc oxide (ZnO), and indium zinc oxide (IZO).

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