DISPLAY DEVICE AND METHOD OF FABRICATING THE SAME

An organic light emitting diode display includes an integrated circuit, a first electrode, a spacer, an organic material stack layer, and a second electrode. The first electrode is electrically connected to the integrated circuit and has a top surface, a bottom surface, and an inclined surface connecting the top and bottom surfaces. An angle between the inclined surface and the bottom surface is in a range from about 45 degrees to about 80 degrees. The spacer is disposed to cover the inclined surface of the first electrode. The organic material stack layer is disposed on the first electrode. The second electrode is disposed on the organic material stack layer and the spacers.

PRIORITY CLAIM AND CROSS-REFERENCE

The present application claims priority to China Application Serial Number 201910899516.7, filed Sep. 23, 2019, which is herein incorporated by reference.

BACKGROUND

Along with the development of technology applied to virtual reality (VR) and augmented reality (AR), head gear devices have become more popular. However, improvements can be made to current yield of fabrication applied to scaled down head gear devices.

DETAILED DESCRIPTION

FIG. 1shows a cross-sectional view of an organic light emitting diode display device according to some embodiments of the present disclosure. The organic light emitting diode display device100includes an integrated circuit110, an insulation layer120disposed on the integrated circuit110, and a plurality of organic light-emitting units140(the figure shows only one for ease of description) disposed on the insulation layer120. Each of the organic light emitting diode units140is electrically connected to the integrated circuit110thereunder through a respective via plug122in the insulation layer120. In some embodiments of the present disclosure, the integrated circuit110and the insulation layer120there-above serve as a base for disposing the organic light emitting diode units140.

In some embodiments of the present disclosure, the organic light emitting diode units140and the integrated circuit110are both fabricated by a semiconductor process for scaling down the organic light emitting diode display device. In other embodiments, the organic light emitting diode display device100can be further attached to other carrier panels. In some embodiments of the present disclosure, the organic light emitting diode units140are micro organic light emitting diodes.

The organic light emitting diode unit140includes a first electrode142, blocking layers144and146, a spacer layer148, an organic material stack layer150, and a second electrode152. The first electrode142is disposed on the insulation layer120, and the second electrode152is arranged opposite to the first electrode142. The organic material stack layer150is disposed between the first electrode142and the second electrode152. The first electrode142can serve as an anode of the organic light emitting diode unit140, and the second electrode152can serve as the cathode of the organic light emitting diode unit140. The organic light emitting diode unit140emits light through the cathode. Therefore, the second electrode152can serve as the light emitting side of the organic light emitting diode unit140.

Two opposite surfaces of the first electrode142are respectively arranged with the blocking layers144,146. Namely, the blocking layer144is disposed between the first electrode142and the insulation layer120, and the blocking layer146is disposed on the surface of the first electrode142opposite the blocking layer144. The blocking layer144serves to block material of the first electrode142from the insulation layer120, such as blocking material from the first electrode142from diffusing into the insulation layer120. The blocking layer146serves to block material of the first electrode142from the organic material stack layer150above the first electrode142, so as to prevent material of the first electrode142from directly contacting the organic material stack layer150above the first electrode142and causing unexpected reactions. In some embodiments of the present disclosure, material of the blocking layers144,146is a metal nitride, such as titanium nitride (TiN) or other similar material.

In some embodiments of the present disclosure, the spacer layer148is disposed on an outer side of the first electrode142, such as covering an outermost sidewall of the first electrode142, and on a top surface of the insulation layer120. The spacer layer148separates the first electrodes142of neighboring organic light emitting diode units140from each other, and prevents the sidewall of the first electrodes142, such as the sidewall of the first electrode142exposed from the blocking layers144,146, from directly contacting the organic material stack layer150.

The organic material stack layer150is deposited on the first electrode142. In some embodiments of the present disclosure, the spacer layer148has an opening region O1, and the organic material stack layer150is filled in the opening region O1. In some embodiments of the present disclosure, the organic material stack layers150of neighboring organic light emitting diode units140can be configured with different organic light emitting layers, so as to emit light of different colors. The organic material stack layers150of the neighboring organic light emitting diode units140can be spaced apart by the spacer layers148, so as to prevent the organic material stack layers150of the different organic light emitting diode units140from directly contacting with each other. The second electrode152is a shared electrode, and extends continuously on top surfaces of the spacer layers148and the organic material stack layers150.

In some embodiments of the present disclosure, the second electrode152is conformally disposed on the organic material stack layers150and the spacer layers148. Namely, a thickness of the second electrode152is generally uniform. Given that the spacer layer148extends from the top surface of the insulation layer120, along the sidewall of the first electrode142, to a top surface of the blocking layer146, a highest position and a lowest position of a top surface of the spacer layer148therefore has an vertical offset G1there-between. In order to maintain the translucency of the second electrode152, the thickness of the second electrode152is usually very thin, and the second electrode152is therefore prone to being broken due to an excessively large offset G1. Some embodiments of the present disclosure reduces the vertical offset G1between the highest position and the lowest position of the top surface of the spacer148, thereby preventing the second electrode152from being broken due to excessively large offset G1.

In some embodiments of the present disclosure, a cross section of the first electrode142is not rectangular, and is wider at the bottom than at the top, such as a trapezoid that is wider at the bottom and narrow at the top. In other words, a top surface142tof the first electrode142is substantially parallel to a bottom surface142bof the first electrode142, an area of the top surface142tof the first electrode142is smaller than an area of the bottom surface142bof the first electrode142, and the top surface142tof the first electrode142and the bottom surface142bof the first electrode142are connected by an inclined surface142sthere-between, wherein the inclined surface142sof the first electrode142is not covered by a blocking layer. An angle θ is included between the bottom surface142bof the first electrode142and the inclined surface142sof the first electrode142.

FIG. 2andFIG. 3each show a cross-sectional view of an organic light emitting diode display device according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the inclined surface142sof the first electrode is not necessarily flat, and can be a curved concave surface as shown inFIG. 2, or a curved convex surface as shown inFIG. 3.

FIG. 4AtoFIG. 4Ceach show a top view of a first electrode of an organic light emitting diode unit according to some embodiments of the present disclosure. In some embodiments of the present disclosure, a shape viewed from above of the first electrode142can be a rectangle as shown inFIG. 4A, a circle as shown inFIG. 4B, a hexagon as shown inFIG. 4C, or other suitable shapes.

Referring back toFIG. 1, in some embodiments of the present disclosure, in each of the organic light emitting diode units140, the first electrode142has the inclined surface142s, and the area of the top surface142tof the first electrode142is less than the area of the bottom surface142bof the first electrode, such that the inclined surface142sof the first electrode142and the bottom surface142bof the first electrode has the angle θ included there-between.

In some embodiments of the present disclosure, the angle θ included between the inclined surface142sof the first electrode142and the bottom surface142bof the first electrode142is in a range between about 45 degrees to about 80 degrees. If the included angle θ is greater than about 80 degrees, then the vertical offset G1cannot be effectively reduced, and also results in a high turning angle of the spacer layer148. For example, the spacer layer148includes a first section1482, a second section1484, and a third section1486that are sequentially connected. The first section1482of the spacer layer148is disposed on the insulation layer120, and substantially extends along the top surface of the insulation layer120. The third section1486of the spacer layer148covers a portion of the blocking layer146, and substantially extends the top surface of the blocking layer146. The second section1484of the spacer layer148substantially extends along the inclined surface142sof the first electrode142, and connects the first section1482of the spacer layer148and the third section1486of the spacer layer148. The vertical offset G1between the highest position and the lowest position of the top surface of the spacer layer148is the vertical distance between the top surface of the first section1482of the spacer layer148and the top surface of the third section1486of the spacer layer148.

If the included angle θ between the inclined surface142sof the first electrode142and the bottom surface142bof the first electrode is greater than about 80 degrees, then the turning angle between the first section1482of the spacer layer148and the second section1484of the spacer layer148, or the turning angle between the second section1484of the spacer layer148and the third section1486of the spacer lay148, may be overly high, and results in a nearly perpendicular turning angle. Given that the second electrode152is conformally fabricated on the spacer layer148, and that the thickness of the second electrode152is very thin, the second electrode152is therefore prone to being broken at locations of high turning angles. On the other hand, if the included angle θ between the inclined surface142sof the first electrode142and the bottom surface142bof the first electrode142is less than about 45 degrees, then a length of the second section1484of the spacer layer148is correspondingly increased such that the distance between the organic light emitting diode units140may be overly long and reduces the resolution of OLED display, or that the light emitting area of the organic light emitting diode unit140is reduced.

Additionally, if the angle θ included between the inclined surface142sof the first electrode142and the bottom surface142bof the first electrode142is greater than about 80 degrees, then the cross-sectional shape of the first electrode may be close a rectangle. If the thickness of the spacer layer148is not sufficient, then the step coverage of the spacer layer148on the first electrode142may be poor, resulting in peeling at a corner of the spacer layer148, such as at the corner between the second section1484and the third section1486of the spacer layer148, such that the organic material stack layer150fabricated subsequently may unwantedly flow into the peeling location of the spacer layer148and in turn contact the first electrode142, resulting in unexpected reactions.

Additionally, when the angle θ included between the inclined surface142sof the first electrode142and the bottom surface142bof the first electrode142is about 80 degrees, if the spacer layer148is to adequately cover the inclined surface142sof the first electrode142, the thickness of the spacer layer148needs to be increased. The spacer layer148with an increased thickness increases a vertical offset G2between the highest position of the top surface of the spacer layer148and the top surface of the organic material stack layer150, such that during subsequent fabrication of the second electrode152, the second electrode152is prone to being broken due to the overly high offset G2, resulting in a decreased yield.

Therefore, embodiments of the present disclosure designs the first electrode142having the inclined surface142s, and the angle θ included between the inclined surface142sof the first electrode and the bottom surface142bof the first electrode142is in a range from about 45 degrees to about 80 degrees. Thereby, the spacer layer148has a smoother topography and a better step coverage on the first electrode142.

Thereby, some embodiments of the present disclosure provides an organic light emitting diode display device, which by modifying a sidewall of the first electrode into an inclined surface, can: provide smoother corners between the first section1482of the spacer layer148and the second section1484of the spacer layer148, or between the second section1484of the spacer layer148and the third section1486of the spacer layer148, further decreasing the chances of being broken of the second electrode152at the corners; allow the spacer layer148to effectively cover the first electrode142by using a thinner thickness, including covering the inclined surface142sand a portion of the top surface of the blocking layer146, assisting in decreasing the overall height of the organic light emitting diode unit140; decrease the vertical offset G1between the highest position and the lowest position of the top surface of the spacer layer148, and decrease the vertical offset distance between the highest position of the top surface of the spacer layer148and the top surface of the organic material stack layer150, further decreasing the chances of disconnection of the second electrode152due to overly high offset distances G1, G2.

FIG. 5AtoFIG. 5Jeach show a cross-sectional view of an organic light emitting diode display device at different fabrication steps of a fabrication method according to some embodiments of the present disclosure.

As shown inFIG. 5A, in step S10an integrated circuit110is fabricated, wherein the integrated circuit110is fabricated using a semiconductor fabrication process. The integrated circuit110includes control circuits, power circuits, switch devices, and related integrated circuits.

Then, as shown inFIG. 5B, in step S20an insulation layer120and a via plug122are formed over the integrated circuit110. In some embodiments of the present disclosure, the step of forming the insulation layer120and the via plug122can include deposing the insulation layer120. The insulation layer120can be for example an inter-metal dielectric (IMD) having a low dielectric constant (k value), such as a dielectric constant lower than about 3.5. The insulation layer120can include a dielectric material, such as silicon oxide or other suitable material.

Then, an opening is formed in the insulation layer120. The opening can be formed by, for example, forming a patterned photoresist layer (not shown in the figure) on the insulation layer120, followed by performing an etching process to remove a portion of the insulation layer120. In this way, the patterned photoresist layer serves as an etch mask to define the resulting opening in the insulation layer. The etching process can include one or more suitable etching processes. After etching, the patterned photoresist layer is removed.

Then, conductive material is deposited to fill the opening, such that the conductive material covers the insulation layer120, and a planarization process is carried out, such as chemical mechanical polishing process, so as to remove excess portion of the conductive material above the top surface of the insulation layer120, such that the via plug122is in the insulation layer120. The material of the via plug122can include copper or copper alloys, or other suitable conductive materials, such as silver, gold, tungsten, aluminum, or other suitable materials. In some embodiments of the present disclosure, the via plug122can further include a barrier layer124arranged between the conductive material and the insulation layer120.

Then, as shown inFIG. 5C, in step S30a blocking layer144′, an electrode layer142′, and another blocking layer146′ are sequentially deposited on the insulation layer120. In some embodiments of the present disclosure, the material of the blocking layer144′ is metal nitride, such as titanium nitride or other suitable materials. The blocking layer144′ serves to separate the material of the electrode layer142′ from the insulation layer120, so as to prevent the material of the electrode layer142′ from diffusing into the insulation layer120. In some embodiments of the present disclosure, a thickness of the blocking layer144′ is from about 50 Å to about 150 Å. If the thickness of the blocking layer144′ is greater than about 150 Å, then the overly great thickness increases the vertical offset G1(seeFIG. 1) between the highest position and the lowest position of the top surface of the spacer layer148(seeFIG. 1). If the thickness of the blocking layer144′ is less than about 50 Å, then the material of the electrode layer142′ may unwantedly diffuse into the insulation layer120.

In some embodiments of the present disclosure, the material of the electrode layer142′ is metal or metal alloys, such that light emitted by the organic light emitting diode unit can be reflected by electrode layer142′ toward the light emitting direction. In order to reduce thickness of the electrode layer142′, the material of the electrode layer142′ can be a conductive material having a low resistance, such as an aluminum copper alloy (AlCu) or other suitable material, so as to avoid overly increasing the resistance when decreasing the thickness. In other embodiments, the material of the electrode layer142′ can include indium tin oxide, gold, tungsten, titanium, or other suitable materials.

In some embodiments of the present disclosure, by adjusting the process conditions of the deposition process, the surface flatness and reflectivity of the electrode layer142′ can be maintained while decreasing the thickness of the electrode layer142′, thus increasing the brightness and contrast of the organic light emitting diode display device. For example, the electrode layer142′ can be fabricated through physical vapor deposition (PVD), and the power and temperature of the physical vapor deposition can be further adjusted to further lower the deposition rate of the electrode layer142′, such that the deposited electrode layer142′ can have a desired surface flatness and thereby maintain the reflectivity of the electrode layer142′. In some embodiments of the present disclosure, the power is from about 1500 W to about 3150 W. If the power is greater than about 3150 W, then the deposition rate may be excessively high and thus the electrode layer142′ may have an uneven surface. In some embodiments, the power can be less than about 2500 W, to achieve a desired surface flatness. If the power is less than about 1500 W, then the deposition cannot be carried out properly.

In some embodiments of the present disclosure, the deposition rate is about 30 Å per second to about 200 Å per second. If the deposition rate is greater than about 200 Å per second, then the overly high deposition rate may result in an uneven surface of the electrode layer142′. If the deposition rate is less than 50 Å per second, then the wafer per hour (WPH) may too low.

In some embodiments of the present disclosure, a desired surface flatness of the electrode layer142′ means that the root mean square roughness (Rms) of the electrode layer142′ is less than about 30 Å, and that the difference between the deepest valley (Rv) and the highest peak (Rp) of the electrode layer142′ is less than about 300 Å. In some embodiments of the present disclosure, the thickness of the electrode layer142′ is about 300 Å to about 900 Å. If the thickness of the electrode layer142′ is greater than about 900 Å, then the overly great thickness increases the vertical offset G1(seeFIG. 1) between the highest position and the lowest position of the top surface of the spacer layer148(seeFIG. 1), thereby increasing the chances of being broken of the second electrode152(seeFIG. 1). If the thickness of the electrode layer142′ is less than about 300 Å, then the electrode layer142′ may be thin enough to be translucent, thus affecting the ability of the electrode layer142′ to reflect light such that light may not be reflected toward the light emitting direction.

In some embodiments of the present disclosure, the material of the blocking layer146′ is also metal nitride, such as titanium nitride or other suitable materials. A thickness of the blocking layer146′ is from about 30 Å to about 200 Å. If the thickness of the blocking layer146′ is great than about 200 Å, then the surface of the blocking layer146′ may be excessively rough, thus degrading the reflectivity of the blocking layer146′. If the thickness of the blocking layer146′ is less than about 30 Å, then the overly thin blocking layer146′ may be damaged in subsequent fabrication processes, thus leading to unwanted contact between the organic material stack layer and the electrode layer142′.

Then, as shown inFIG. 5D, in step S40a positon of the first electrode is defined. Step S40includes forming a patterned photoresist layer160, so as to use the patterned photoresist layer160as a mask for defining the positon of the first electrode142. The position of the patterned photoresist layer160at least covers the via plug122.

Then, refer toFIG. 5DandFIG. 5E, in step S50the electrode layer142′ and the blocking layers144′,146′ are etched by using the patterned photoresist layer160as an etch mask, resulting in the patterned first electrode142, and the patterned blocking layers144,146positioned above and below the first electrode142. The patterned photoresist layer160is removed after etching. As mentioned above, in some embodiments of the present disclosure, the first electrode142has an inclined surface142s, and the angle θ included between the inclined surface142sof the first electrode142and the bottom surface142bof the first electrode is in a range from about 45 degrees to about 80 degrees.

For example, in some embodiments of the present disclosure, the etching process used is dry etching, and the pressure is from about 4 mTorr to about 10 mTorr, the source radio frequency is from about 600 W to about 1600 W, the bias radio frequency is from about 40 W to about 200 W, the etchant gas can include boron chloride (BCl3), the etchant gas flow rate is from about 50 standard cubic centimeters per minute (sccm) to about 500 sccm. If etching conditions are outside these ranges, then the range of the included angle θ can be greater than about 80 degrees or less than about 45 degrees. If the included angle is greater than about 80 degrees, then the second electrode152(seeFIG. 1) may be broken. If the included angle θ is less than about 45 degrees, then the interval between the organic light emitting diode units may be overly long, which in turn leading to reduced resolution of display or reduced light emitting area of the organic light emitting diode unit.

After etching, the blocking layer144and the blocking layer146are disposed on only the top surface and the bottom surface of the first electrode142, and do not cover the inclined surface142sof the first electrode142. Given that the cross-sectional shape of the first electrode142is narrow at the top and wide at the bottom, the area of the bottom surface of the blocking layer144is greater than the area of the top surface of the blocking layer146. In some embodiments of the present disclosure, a total thickness of the first electrode142, the blocking layer144, and the blocking layer146can be less than about 1000 Å, such as being controlled within a range of about 600 Å to about 800 Å.

Then, as shown inFIG. 5F, in step S60a dielectric layer148′ is covered on the first electrode142, the blocking layers144,146, and the insulation layer120. The material of the dielectric layer148′ can be the same as or different from the material of the insulation layer120. For example, the material of the dielectric layer148′ can be an oxide, a nitride, an oxynitride or other suitable material, such as silicon oxide, silicon nitride, silicon oxynitride, or other suitable materials.

Given that the sidewall of the first electrode142is the inclined surface142s, the dielectric layer148′ can therefore completely cover the first electrode142and the blocking layers144,146with a thinner thickness, and has good step coverage without peeling at corners. Additionally, given that the total thickness of the first electrode142, the blocking layer144and the blocking layer146can be less than about 1000 Å, the dielectric layer148′ can therefore cover the first electrode142, the blocking layers144,146and the insulation layer120more smoothly, without a high turning angle (over 80 degrees) at the corner.

For example, in some embodiments of the present disclosure, a thickness of the dielectric layer148′ is from about 100 Å to about 400 Å. If the thickness of the dielectric layer148′ is less than 100 Å, then the dielectric layer148′ might not completely cover the first electrode142, the blocking layers144,146and the insulation layer120. If the thickness of the dielectric layer148′ is greater than 400 Å, then the overly great thickness increases the vertical offset distance G2(seeFIG. 1) between the highest position of the top surface of a subsequently formed spacer layer148(seeFIG. 1) and the top surface of a subsequently formed organic material stack layer150(seeFIG. 1), such that when subsequently fabricating a second electrode152(seeFIG. 1), the second electrode152(seeFIG. 1) is prone to being broken due to the overly high vertical offset G2(seeFIG. 1), thus resulting in a decreased yield.

Then, referring toFIG. 5G, in step S70another patterned photoresist layer162is formed on the dielectric layer148to define an opening for forming the organic light emitting diode unit.

Afterward, referring toFIG. 5GandFIG. 5H, in step S80the dielectric layer148′ is etched using the patterned photoresist layer162as an etch mask, resulting in the spacer layer148covering the sidewall of the first electrode142. The patterned photoresist layer162is removed after etching.

For example, the portion of the dielectric layer148′ not covered by the patterned photoresist layer162is removed to define an opening region O1, and the portion of the dielectric layer148′ covered by the patterned photoresist layer162remains on the first electrode142and the insulation layer120to form the spacer layer148. The opening region O1extends through the spacer layer148.

In some embodiments of the present disclosure, a thickness of the spacer layer148is from about 100 Å to about 400 Å. The opening ratio of the first electrode142, namely the ratio of the area of the top surface of the blocking layer146exposed at the opening region O1to the total area of the top surface of the blocking layer146, is greater than or equal to about 98%.

Given that the blocking layer146serves as an etch stop layer during the fabrication of etching the dielectric layer148′, a portion of the blocking layer146not covered by the patterned photoresist layer162may be inevitably partially removed during the etching process, resulting in a thickness t4of a portion of the blocking layer146between the spacer layer148and the first electrode142being greater than a thickness t3of a portion of the blocking layer146exposed at the opening region O1. As mentioned above, an original thickness of the blocking layer146, namely the thickness t4, or the thickness of the blocking layer146′ deposited inFIG. 5D, is greater than about 30 Å, to prevent the portion of the blocking layer146not covered by the patterned photoresist layer162from being overly etched in the etching process of step S80and resulting in the first electrode142thereunder being exposed at the opening region O1.

Then, referring toFIG. 5IandFIG. 6, in step S90as shown inFIG. 5Ithe organic material stack layer150is formed in the opening region O1above the first electrode142.FIG. 6is an enlarged view of region R ofFIG. 5I. In some embodiments of the present disclosure, the organic material stack layer150is a stack of multiple layers including different materials. For example, the organic material stack layer150can include a stack of hole-injecting layer (HIL), organic hole-transporting layer (HTL), organic light-emitting layer (LEL), electron-transporting layer (ETL), and electron-injecting layer (EIL). In other embodiments, the organic material stack layer150can further selectively include an electron-blocking layer and a hole-blocking layer.

In some embodiments of the present disclosure, the organic material stack layer150is formed on the blocking layer146, and is filled in the opening region O1defined by the spacer layer148.

By selecting different materials for different organic light emitting layers, different organic light emitting diode units can emit light of different colors. In some embodiments of the present disclosure, the display device comprising a plurality of organic light emitting diode units can include organic light emitting diode units emitting red light, organic light emitting diode units emitting blue light, and organic light emitting diode units emitting green light.

In some embodiments of the present disclosure, the organic material stack layer150can be fabricated in the opening region O1through evaporation. In some embodiments of the present disclosure, organic material stack layers of different colors can be formed in the opening regions of organic light emitting diode units of different colors through separate evaporation fabrications. For example, organic material stack layer for emitting red light can be first fabricated in the opening region of organic light emitting diode units for emitting red light, then organic material stack layer for emitting green light can be fabricated in the opening region of organic light emitting diode units for emitting green light, and finally organic material stack layer for emitting blue light can be fabricated in the opening region of organic light emitting diode units for emitting blue light. The organic material stack layers of the different organic light emitting diode units can be spaced apart by the spacer layers148.

The organic material stack layer150and the first electrode142are spaced apart by the blocking layer146, to prevent direct contact between the organic material stack layer150and the first electrode142resulting in unexpected reaction.

Referring again toFIG. 5I, in some embodiments of the present disclosure, a thickness t5of the organic material stack layer150can be less than a thickness t6of the spacer layer148, such that the organic material stack layer150does not completely fill the opening region O1. In other words, the height of the top surface of the organic material stack layer1550is lower than the height of the highest position of the top surface of the spacer layer148.

Then, referring toFIG. 5J, in step S100the second electrode152is formed on the organic material stack layer150. In some embodiments of the present disclosure, the second electrode152can be a shared electrode of multiple organic light emitting diode units140. The second electrode152can be fabricated through evaporation onto the organic material stack layer150and the spacer layer148. In some embodiments of the present disclosure, the material of the second electrode152is metal, such as silver. In other embodiments of the present disclosure, the material of the second electrode152can also be a transparent electrical conductive material, such as indium tin oxide or other suitable material.

As shown inFIG. 5J, the thickness t4of a first portion1462of the blocking layer146between the spacer layer148and the first electrode142is greater than the thickness t3of a second portion of the blocking layer146between the organic material stack layer150and the first electrode142. The second electrode152is evenly formed on the top surface of the organic material stack layer150and the top surface of the spacer layer148, and therefore has an undulating top surface. Some embodiments of the present disclosure lowers the difficulty for fabricating the second electrode152, and effectively prevents unexpected breaking of the second electrode152, by reducing the vertical offset distance G1between the highest position and the lowest position of the top surface of the spacer layer148.

Additionally, given that the shape of the first electrode is a trapezoid having a slanted corner, and that the angle θ included between the inclined surface142sof the first electrode and the bottom surface142bof the first electrode is in a range between about 45 degrees to 80 degrees, the spacer layer148can have a smoother surface shape. Therefore, the second electrode152arranged on the spacer layer148can also avoid rising at great (i.e. sharp) angles, thereby reducing the risk of breaking.

FIG. 7andFIG. 8each show a cross-sectional view of an organic light emitting diode display device according to different embodiments of the present disclosure. In some embodiments, such as the organic light emitting diode unit140ashown inFIG. 7, the organic material stack layer150asubstantially completely fills the opening region Ola. Namely, the top surface of the organic material stack layer150ais substantially level with the highest position of the spacer layer148a. In other embodiments, such as the organic light emitting diode unit140bshown inFIG. 8, the thickness t5bof the organic material stack layer150bcan be greater than the thickness t6bof the spacer layer148b, thus the organic material layer150bcompletely fills the opening region Olb and protrudes from the spacer layer148b, such that the top surface of the organic material stack layer150bis higher than the highest position of the top surface of the spacer layer148b.

In summary, some embodiments of the present disclosure can effectively reduce the thickness of the spacer layer by designing the sidewall of the first electrode as an inclined surface, such that the spacer layer has a smoother surface shape, thereby reducing the risk of breaking of the second electrode.

Next,FIG. 9shows a schematic diagram of an exterior of a headgear device according to some embodiments of the present disclosure. A headgear device200includes a frame210, a projection device220arranged at two sides of the frame210, and an imaging screen230arranged at the front side of the frame210. For example, the frame210has ear hook portions212at two sides and a panel portion214at a front side. The panel portion214has at least one opening. The imaging screen230is embedded in the panel portion214. The quantity of the projection device220can be one or multiple. If the quantity of the projection device220is two, then the two projection devices220are respectively arranged on the ear hook portions212, to project onto the imaging screen230.

In some embodiments of the present disclosure, the projection device220of the headgear device200includes the abovementioned organic light emitting diode display device (such as the organic light emitting diode display device100shown inFIG. 1). The structure and fabrication of this organic light emitting diode display device is described in the above embodiments, and is not further described herein.

In some embodiments of the present disclosure, the projection device220can be controlled by a processor and receive signals from the processor to output corresponding imaging lights. In some embodiments of the present disclosure, one or more reflective or optical lenses can be arranged between the projection device220and the imaging screen230, for adjusting the light path of the imaging light outputted by the projection device220. In some embodiments of the present disclosure, the projection device220can further include a heat dissipation unit. The heat dissipation unit can be for example a heat sink, a heat dissipation film, etc. The heat dissipation u nit can be thermally coupled to the organic light emitting diode array, to prevent heat from building up in the projection device220and causing damage.

In some embodiments of the present disclosure, the headgear device200can be a transmissive headgear device, namely an image seen by the user can be a combination of an image provided by the projection device220and an image of the outside environment. In some embodiments of the present disclosure, the headgear device200can be a reflective headgear device, namely an image seen by the user is an image provided by the projection device220.

FIG. 10andFIG. 11each show a cross-sectional view of a liquid crystal on silicon (LCOS) display panel at different fabrication steps according to some embodiments of the present disclosure.FIG. 10shows a fabricated structure, including an integrated circuit310, an insulation layer320disposed on the integrated circuit310, a plurality of first electrodes330(the figure shows only one for simplicity) disposed on the insulation layer320, blocking layers340,342disposed at two sides of the first electrode330, and a spacer layer350disposed at a sidewall of the first electrode330. Each of the first electrodes330is electrically connected to the integrated circuit310thereunder through a via plug322disposed in the insulation layer320.

Method for fabricating the integrated circuit310, the insulation layer320, the via plug322, the first electrode330, the blocking layers340,342, and the spacer layer350can reference steps S10to step S80described byFIGS. 5A to 5H, and is not further repeated herein.

Referring next toFIG. 11,FIG. 11shows an opposite substrate360and a liquid crystal layer370. A second electrode380is disposed on the opposite substrate360. The second electrode380is a shared electrode. In some embodiments of the present disclosure, the second electrode380covers the entire surface of the opposite substrate360facing the first electrode330. The second electrode380can be an electrically conductive material having a high translucency, such as indium oxide (In2O3), tin oxide (SnO2), indium tin oxide (ITO), zinc oxide (ZnO), or other suitable material.

In some embodiments of the present disclosure, the liquid crystal layer370can be first formed on the spacer layer350and the first electrode330, and then be mated to the opposite substrate360for completing fabrication, thereby obtaining an LCOS display panel300. In some embodiments of the present disclosure, the opposite substrate360can be first placed over the integrated circuit310but leaving a space there-between, and then the liquid crystal layer370is injected between the integrated circuit310and the opposite substrate360. In some embodiments of the present disclosure, an alignment layer can be arranged between the liquid crystal layer370and the first electrode330, and between the liquid crystal layer370and the second electrode380.

By modifying the sidewall of the first electrode330into an inclined surface, the required thickness of the spacer layer350can be effectively reduced, and the spacer layer350can have good step coverage on the first electrode330and have a smoother surface shape, thereby solving the issue of breaking or peeling of the spacer layer350at corners.

FIG. 12shows a block diagram of a projection device in a headgear device according to some embodiments of the present disclosure. The projection device220can be applied to the headgear device200such as the one shown inFIG. 9. In some embodiments of the present disclosure, the projection device220includes a light source222, an optical unit224, and an LCOS display panel226. The LCOS display panel226is configured to receive colored light from the light source and image signals from a controller, to integrate and emit imaging light for projection.

In some embodiments of the present disclosure, the optical unit224in the projection device220includes one or more optical lenses disposed at a light emitting side of the light source222, for adjusting the light path of the light emitted by the light source222. In some embodiments of the present disclosure, the light emitted by the light source222is white light, the optical unit224includes a beam splitting unit disposed between the light source222and the LCOS display panel226. The white light emitted by the light source222can pass through the optical lens and enter the beam splitting unit, such that the white light emitted by the light source222is split into the three primary colors of light, red light, blue light, and green light, after passing through the beam splitting unit. The red light, the blue light, and the green light are emitted according to a timing sequence.

In other embodiments, the light source222can be controlled by a program such as a processor, such that the light source222can switch very rapidly to emit according to a timing sequence the three primary colors of light, the red light, the blue light, and the green light. In this case the beam splitting unit may be omitted.

In some embodiments of the present disclosure, the optical unit224can include a polarizing beam splitter (PBS). The three primary colors of light, regardless of being obtained by using the beam splitting unit to split white light emitted by the light source222, or being directly emitted by the light source222, enters the LCOS display panel226after passing through the polarizing beam splitter, and the LCOS display panel226outputs a full color image beam to be outputted to the imaging screen230for being displayed.

Similarly, one or more reflective lenses or optical lenses can be configured between the LCOS display panel226and the imaging screen230, for adjusting the light path of the image beam outputted by the LCOS image display panel226. In some embodiments of the present disclosure, the projection device220can further include a heat dissipating unit. The heat dissipating unit can be for example a heat sink, a heat dissipating film, etc. The heat dissipating unit can be thermally coupled to the light source222, to prevent heat from building up in the light source222and causing damage.

In summary, some embodiments of the present disclosure provide a display device and a method for fabricating the same. By designing the sidewall of the first electrode, such as the anode, of the display unit of the display device as an inclined surface, the required thickness of the spacer layers is effectively reduced, and the spacer layer can have a smoother surface shape, thereby preventing the issue of disconnection of the second electrode.

According to embodiments of the present disclosure, an organic light emitting diode display device includes an integrated circuit, a first electrode, a spacer layer, an organic material stack layer, and a second electrode. The first electrode is electrically connected to the integrated circuit. The first electrode has a top surface, a bottom surface, and an inclined surface connecting the top surface and the bottom surface. An angle included between the inclined surface and the lower surface is in a range from about 45 degrees to about 80 degrees. The spacer layer covers the inclined surface of the first electrode. The organic material stack layer is disposed on the first electrode. The second electrode is disposed on the organic material stack layer and the spacer layer.

According to embodiments of the present disclosure, a method for fabricating an organic light emitting diode display device includes forming an electrode layer on an insulation layer, wherein the electrode layer is electrically connected to an integrated circuit through a via plug in the insulation layer. Then, the electrode layer is etched, wherein the electrode layer is etched by dry etching, and a reactant gas of the dry etching include boron chloride (BCl3), such that a first electrode has a top surface, a bottom surface, and an inclined surface connecting the top surface and the bottom surface. A spacer layer is formed to cover the inclined surface of the first electrode. An organic material stack layer is formed on the first electrode. A second electrode is formed on the organic material stack layer and the spacer layer.

According to embodiments of the present disclosure, a method for fabricating a liquid crystal on silicon (LCOS) display panel include forming an electrode layer on an insulation layer, wherein the electrode layer is electrically connected to an integrated circuit through a via plug in the insulation layer, and a deposition rate for forming the electrode layer is from about 30 Å of thickness per second to about 200 Å of thickness per second, such that a thickness of the electrode layer is between about 300 Å to about 900 Å. Then, the electrode layer is etched, so as to obtain a first electrode. A spacer layer covering a sidewall of the first electrode is formed. A liquid crystal layer and a second electrode are formed on the first electrode and the spacer layer.