TWI481300B - Organic electroluminescent devices and their test methods - Google Patents

Description

Organic electroluminescent device and test method thereof

The invention relates to an organic light emitting device (hereinafter referred to as OLED) and a testing method thereof, in particular to a lead design of an OLED.

OLED is a flat panel display device which is made by the phenomenon that carriers are combined by an anode and a cathode into an organic functional layer under the action of an electric field to emit light. OLED has all-solid, self-illuminating, high contrast, ultra-thin, soft display.

The current electronic devices are tested and tempered before leaving the factory to test the device performance. Corresponding to different wafer bonding technologies, different problems will occur during the testing and refining phase. The screen is bonded to the wafer by a COG (Chip on Glass) method. Referring to FIG. 1-1 and FIG. 1-2, the OLED includes a substrate 103 and a light-emitting region 102. The light-emitting region 102 is composed of an anode 1002 located on the substrate 103. The functional layer 1003 and the cathode 1004 are formed. The left and right sides and the lower edge of the light-emitting region 102 are provided with a lead region 101, and a lower edge of the lead region 101 is provided with a binding region 104. The odd row lead 101 [1] is drawn from the left side of the light emitting region 102; the even row lead 101 [2] is drawn from the right side of the light emitting region 102; the left column lead 101 [3] and the right column lead 101 [4] are taken out from below the light emitting region 102. After the row leads and the column leads are respectively led out, they are concentrated in the bonding area 104 in an insulated manner, and are bound on one side of the substrate, that is, unilaterally bound.

For the sake of clarity, all row and column leads are not drawn. Because the COG product screen lead gap is too small, the narrow space can only use a narrower conductive strip, so that when the conductive strip is crimped with the lead: (1) the conductive strip is easily misaligned and the screen is short-circuited; (2) The life of the conductive strip is shortened; (3) The lead is broken. When the gap between the leads is less than the minimum alignment accuracy that can be achieved by the test and the old refining tool, the screen cannot be illuminated by the short bar method, and the test and aging of the screen cannot be performed. Can be discovered after binding to the driver chip. It is currently impossible to perform screen testing and aging for such products, and it is difficult to guarantee high yield.

The OLED leads are prepared by photolithography. Important process conditions include etching temperature, speed, time, and etchant concentration. Any process parameters are not well mastered and may cause over-etching. If there is no lead extension, the end of the lead is bonded to the drive wafer. The over-etched leads are shorter than the length required for bonding, and these over-etched leads cannot be in contact or poorly contacted with the corresponding wafer pins, resulting in the corresponding rows or columns of the illumination regions not being illuminated. As shown in FIG. 2-1, the left column lead 201 and the right column lead 202 are over-etched, and the length thereof is shorter than the length required for bonding, and cannot be in contact with the wafer pins. If the binding position is moved up, as shown in FIG. 2-2, the left column lead 201 and the right column lead 202 can be normally bound, but in this way, the chip pins reach the left column lead 203 and the right column lead. In the bent position of 204, the left column lead 203 and the right column lead 204 cannot be normally connected to the corresponding wafer pins.

The present invention provides a lead design for an OLED that can be tested and guaranteed to have a test effect.

The object of the present invention is achieved by the following technical solutions: an organic electroluminescent device includes a light emitting region, a lead region, a binding region, the light emitting region includes an anode, an organic functional layer, and a cathode; and the lead region is made of an anode and a cathode and a driving wafer or The lead wire of the circuit board is connected; the binding area is an area where the lead is connected to the driving chip or the circuit board; and the lead extending area is included, the end of the lead is located in the lead extending area, and the lead of the lead extending area forms an angle with the lead of the lead area is larger than 0° and less than 90°.

The lead of the lead extension region forms an angle with the leads of the lead region that is greater than 20° and less than 80°, preferably 30°, 45°, 60° or 75°.

When the leads are unilaterally bound, they are divided into odd row leads, even row leads, left column leads, and right column leads. The column leads are in the middle, and the odd row leads and the even row leads are separated on both sides of the column leads. When the left column lead and the right column lead extend in directions away from each other, the odd row leads and the even row leads may extend in opposite directions or may extend away from each other, and all row and column leads do not intersect. Similarly, when the left and right column leads extend in opposite directions, the odd row and even row leads may also extend in opposite or opposite directions, and all row and column leads do not intersect. Also, the angles of the extensions of the odd row leads, the even row leads, the left column leads, and the right column leads may be different.

The leads of the lead extension area may be smaller than the leads of the lead area. That is, when the lead of the lead extension area extends at an angle to the vertical direction, in order to ensure that all the row and column leads do not intersect, the end of the part of the lead may be located in the binding area without extending to the lead extension area.

The lead length of the lead extension region is preferably from 0.1 mm to 0.5 mm.

Another object of the present invention is to provide a test method for an OLED.

The object of the present invention is achieved by the following technical solution: a method for testing the above organic electroluminescent display device, the testing step includes: (1) shorting the row lead to be lit, short-circuiting the column lead to be lit; 2) The row or column lead which short-circuits step (1) is given a lighting voltage; (3) the test result is given according to the test condition.

Step (1) can short all odd row leads, short all even row leads, and short all column leads. Step (1) can also short-circuit all the row leads and short-circuit all the column leads.

Step (1) uses a conductive material to connect the leads to be short-circuited, and the conductive material is a metal film or a conductive strip.

The present invention changes the lead arrangement of the OLED, and respectively separates the row and column leads away from each other or relative to each other: (1) Since the row and column leads are respectively connected to the anode or the cathode of the OLED, the row leads cannot be connected to the column leads. The lead design of the present invention increases the spacing of the row and column leads, preventing shorting of the row and column leads during the screen test phase. (2) The row and column leads are inclined at a certain angle, and can have a larger lead extension length in the extended area of the finite size as compared with the case of not tilting, so that the contact area with the conductive strip is increased, and the unit area is The current load shared by the conductive medium is reduced, thereby increasing the life of the conductive strip. (3) The width of the row and column leads in the horizontal direction is increased, which satisfies the requirements of the minimum alignment accuracy of the current test and the old refining tool, so that the conductive strip can be crimped with the lead more easily and accurately.

The corresponding test method guarantees the aging and testing of OLEDs, ensuring high yield.

In addition, the end of the lead is located in the lead extension, i.e., not bonded at the end of the lead. In this way, even if the etching is performed when the wiring is etched, the end of the lead is not used, thereby ensuring good contact between all the leads and the wafer pins, and the binding effect is ensured.

In the present invention, the direction of the OLED from the substrate to the cathode is the longitudinal direction, and the direction perpendicular thereto is the lateral direction. It should be noted that the lead regions, the bonding regions, and the lead extension regions are defined for convenience of description, but it does not mean that the leads of the regions are independent of each other, but are a whole, which is formed by a photolithography process at a time. A portion between the light-emitting region and the binding region constitutes a lead region; a portion between the bonding region and the lower edge of the substrate constitutes a lead extension region.

The technical solution of the present invention adopts a new mask, so that the pattern of the lithographic leads is different from the prior art.

OLED manufacturing processes typically include:

(1) sputtering an electrode material on a glass substrate, usually composed of a transparent conductive material such as indium tin oxide (hereinafter referred to as ITO) or tin zinc oxide, and the lithographic ITO pattern includes a portion as an anode of the OLED device and as an electrode lead part. When the lead is too long or too thin, a large voltage drop is generated on the lead, and the luminous intensity of the display area is reduced. In order to reduce the electrical resistance as much as possible, chromium is usually added to the ITO as a lead. Therefore, the electrode lead usually comprises two layers of ITO and chromium.

(2) An insulating layer and a spacer are prepared by photolithography, which is a necessary process for realizing RGB color, and different pixels are separated to realize a pixel array.

(3) Depositing an organic electroluminescent material by vacuum evaporation to form an organic functional layer, including a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and the like.

(4) The cathode material is covered by vacuum evaporation.

(5) The grooved glass substrate to which the dried sheet is attached is pressed together with the OLED substrate to realize packaging, and the damage of the water and oxygen components to the device is reduced.

(6) The electrode lead is bound to the driving chip or the circuit board to realize the connection between the light emitting area and the driving chip or the circuit board. The bonding method of the lead and the wafer is: single-sided bonding, that is, all the row and column leads are arranged on one side of the substrate and connected to one wafer, as shown in FIG. 1-1; bilateral bonding, that is, the row leads are arranged on the substrate. On one side, the column leads are arranged on the other side of the substrate, and are respectively connected to one wafer. Usually unilateral bonding saves space on the edge of the device and the number of wafers.

The present invention will be further described below in conjunction with the embodiments and the accompanying drawings.

Example 1

As shown in Fig. 3 and Fig. 4, Example 1 is a 96-row x 16-column organic electroluminescent device.

The light-emitting area laterally leads out the odd-numbered row leads 401 [1] and the even-numbered row leads 401 [2], and the left-row lead 401 [3] and the right-column lead 401 [4] are drawn longitudinally. The ends of the leads are located in lead extensions 300. After the left column lead 401 [3] is bonded to the wafer pin, the end of the left column lead 401 [3] extends to the left side 30° from the vertical direction; the right column lead 401 [4] is bound to the wafer pin, and the end thereof After extending beyond the wafer pins, it extends 30° to the right in the vertical direction; after the odd-numbered row leads 401[1] are bonded to the wafer pins, the ends extend beyond the wafer pins 30° to the right in the vertical direction; After the row leads 401 [2] are bonded to the wafer pins, the ends thereof extend beyond the wafer pins 30 degrees to the left in the vertical direction. The length of the lead in the lead extension is 0.4 mm. The odd row lead 401 [1], the even row lead 401 [2] the left column lead 401 [3], and the right column lead 401 [4] do not intersect each other.

The process steps for preparing the leads of the above organic electroluminescent device of the present embodiment include:

(1) A glass substrate that has been cleaned and dried is placed in a lithographic apparatus on which an ITO layer and a metallic chromium layer thereon have been prepared.

(2) Applying a photoresist on the ITO and chromium layers by spin coating and baking.

(3) The mask is covered on the photoresist, and the surface of the photoresist is irradiated with ultraviolet light (UV) through the mask to selectively expose the photoresist.

(4) Development and hardening.

(5) Etching. Etching ITO and chromium are different in etching solution, which are water, hydrochloric acid, nitric acid mixed etching solution with a concentration ratio of 10:10:1, water with a concentration ratio of 10:2:1, ammonium cerium nitrate and nitric acid. Etching solution.

The etched lead pattern is shown in FIG. 3. After the etching is completed, it is placed in the vapor deposition chamber to prepare the organic functional layer and the cathode, and then the package lid coating process in the isolation chamber is completed. The substrate after the encapsulation step is taken out, and the test process before the bonding is started: in this embodiment, the conductive strip is used to realize the short circuit of each part of the lead, and the blocks 402, 403 and 404 in FIG. 4 are the conductive strip crimping area, 402. The conductive strip is connected to all the odd row leads 401 [1] of the conducting screen body, and the conductive strip of the 403 is connected to all the column leads 401 [3] and 401 [4] of the conducting screen body, and the conductive strips of the 404 are connected to turn on all the even row leads. 401 [2], the distance between the three conductive strips is about 1.6mm, which is much larger than the minimum alignment accuracy of the test device - 0.8mm, which can effectively realize the test. The conductive pads on the PCB of the test device are respectively divided into three places. The conductive strips at the conductive position are electrically connected, and the test screen is illuminated and recorded in full screen. After the test is completed, the three conductive strips are removed from the screen body, and the screen body enters the next stage of binding with the driving wafer.

Example 2

As shown in Fig. 5, Example 2 is also a 96-row by 16-column organic electroluminescent device. The light-emitting area laterally leads out the odd-numbered row leads 501 [1] and the even-numbered row leads 501 [2], and the left-row lead 501 [3] and the right-column lead 501 [4] are drawn longitudinally. The ends of the leads are located in lead extensions 500. After the left column lead 501 [3] is bonded to the wafer pin, the end of the left column lead 501 [4] extends to the left side 45 degrees from the vertical direction; the right column lead 501 [4] is bonded to the wafer pin, and the end thereof After extending beyond the wafer pin, it extends 45° to the right in the vertical direction; after the odd-numbered row of leads 501[1] is bonded to the wafer pin, the end extends beyond the wafer pin and extends 45° to the left in the vertical direction; After the row lead 501 [2] is bonded to the wafer pin, its end extends beyond the wafer pin and extends 45° to the right in the vertical direction. The length of the lead in the lead extension is 0.5 mm. The odd row lead 501 [1], the even row lead 501 [2] the left column lead 501 [3], and the right column lead 501 [4] do not intersect each other.

The process steps for preparing the leads of the organic electroluminescent device of the present embodiment are the same as those of the embodiment 1, and are not described herein again.

After the etching is completed, the organic functional layer and the cathode are prepared in the vapor deposition chamber, and then the package lid coating process in the isolation chamber is completed. The substrate after the encapsulation step is taken out, and the test process before the binding is started. The test procedure is basically the same as that of the first embodiment. In this embodiment, the zebra strip is used to realize the short circuit of each part of the lead. In FIG. 5, the lead extension area 500 is the zebra strip. The location of the application. After the test is completed, the zebra strip is removed from the screen body, and the screen body enters the next stage of binding with the driving chip.

Example 3

As shown in Fig. 6 and Fig. 7, Example 3 is a 64-row by 128-column organic electroluminescent device. The light-emitting area laterally leads out the odd-numbered row leads 701 [1] and the even-numbered row leads 701 [2], and the left-row lead 701 [3] and the right-column lead 701 [4] are drawn longitudinally. The ends of the leads are located in lead extensions 700. After the left column lead 701 [3] is bonded to the wafer pin, the end of the left column lead 701 [3] extends to the right side 60° from the vertical direction; the right column lead 701 [4] is bound to the wafer pin, and the end thereof After extending beyond the wafer pins, it extends 60° to the left in the vertical direction; after the odd-numbered row leads 701[1] are bonded to the wafer pins, the ends extend beyond the wafer pins and extend 60° to the right in the vertical direction; After the row leads 701 [2] are bonded to the wafer pins, the ends thereof extend beyond the wafer pins and extend to the left side at 60 degrees from the vertical direction. The length of the lead in the lead extension is 0.1 mm. The odd row lead 701 [1], the even row lead 701 [2] the left column lead 701 [3], and the right column lead 701 [4] do not intersect each other.

The process steps for preparing the leads of the organic electroluminescent device of the present embodiment are the same as those of the embodiment 1, and are not described herein again.

One of the left column leads 601 and the right column lead 602 are adjacent leads that may intersect if they extend beyond the wafer to the right and left, respectively. Therefore, in order to prevent the ends of the left column lead 601 and the right column lead 602 from intersecting, the ends of the left column lead 601 and the right column lead 602 are located in the binding region, that is, the two leads are not extended to the lead extension after being bound to the wafer pins. Area.

The test procedure is the same as that of Embodiment 1, and details are not described herein again.

Example 4

As shown in Fig. 8, Example 4 is also a 64-row by 128-column organic electroluminescent device. The illuminating area laterally leads out odd row leads 801 [1] and even row leads 801 [2], and the left column lead 801 [3] and the right column lead 801 [4] are drawn longitudinally. The ends of the leads are located in lead extensions 800. After the left column lead 801 [3] is bonded to the wafer pin, the end of the left column lead 801 [3] extends to the right side 75 degrees from the vertical direction; the right column lead 801 [4] is bonded to the wafer pin, and the end thereof After extending beyond the wafer pins, it extends 75° to the left in the vertical direction; after the odd-numbered row leads 801[1] are bonded to the wafer pins, the ends extend beyond the wafer pins and extend 75° to the left in the vertical direction; After the row leads 801 [2] are bonded to the wafer pins, the ends thereof extend beyond the wafer pins and extend 75° to the right in the vertical direction. The length of the lead in the lead extension is 0.2 mm. The odd row lead 801 [1], the even row lead 801 [2] the left column lead 801 [3], and the right column lead 801 [4] do not intersect each other.

The process steps and test procedures for preparing the leads of the organic electroluminescent device of the present embodiment are the same as those of the embodiment 2, and are not described herein again.

Embodiments 2, 3, and 4 are the same as the photolithography process steps of Embodiment 1, except that since the patterns of the leads are different, the mask used in photolithography is different.

According to the lead structure described in Embodiments 1 to 4, the present invention employs a new mask, and the pattern of the lithographic leads is different from the prior art in that the row and column leads are respectively moved away from each other or relatively. The lead design of the present invention increases the spacing of the row and column leads, preventing shorting of the row and column leads during the screen test phase. The row and column leads are inclined at a certain angle, the contact area with the conductive strip is increased, and the current load shared by the conductive medium per unit area is reduced, thereby improving the life of the conductive strip.

By adopting the lead structure and the test method of Embodiments 1 to 4 of the present invention, the inventors successfully tested and tempered the COG product with the current test and the old refining tooling, thereby ensuring high yield.

In addition, since the end of the lead is located in the lead extension area, that is, it is not bonded at the end of the lead. As a result, even if etching occurs when the wiring is etched, the end of the lead is not used, thereby ensuring good contact between the lead and the wafer pin, and the lead structure does not increase the number of process steps.

Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the invention, and any person skilled in the art can make various changes and refinements without departing from the spirit and scope of the invention. The scope of protection of the invention is defined by the scope of the patent application.

101. . . Lead area

102. . . Luminous area

103. . . Substrate

104, 205. . . Binding area

1002. . . anode

1003. . . Organic functional layer

1004. . . cathode

300, 500, 700, 800. . . Lead extension

402, 403, 404. . . Conductive strip crimping zone

101[1], 401[1], 501[1], 701[1], 801[1]. . . Odd row leads

101[2], 401[2], 501[2], 701[2], 801[2]. . . Even row lead

101[3], 401[3], 501[3], 701[3], 801[3], 201, 203, 601. . . Left column lead

101[4], 401[4], 501[4], 701[4], 801[4], 202, 204, 602. . . Right column lead

1-1 is a schematic view of a screen of a conventional organic electroluminescent device;

1-2 is a schematic longitudinal cross-sectional view showing the structure of an organic electroluminescent device;

Figure 2-1 is a schematic diagram of the existing binding in the case of lead over-etching;

2-2 is a schematic diagram of the upward movement of the binding region in the case of lead over-etching;

3 is a schematic diagram of binding according to Embodiment 1 of the present invention;

Figure 4 is an enlarged view of the area shown by 301 in Figure 3;

FIG. 5 is a schematic diagram of binding according to Embodiment 2 of the present invention; FIG.

FIG. 6 is a schematic diagram of binding according to Embodiment 3 of the present invention; FIG.

Figure 7 is an enlarged view of the area indicated by 603 in Figure 6;

FIG. 8 is a schematic diagram of binding according to Embodiment 4 of the present invention.

402, 403, 404. . . Conductive strip crimping zone

401[1]. . . Odd row leads

401[2]. . . Even row lead

401[3]. . . Left column lead

401[4]. . . Right column lead

Claims (17)

An organic electroluminescent device comprises a substrate, a light-emitting region, a lead region, a binding region, a light-emitting region, a lead region and a binding region formed on the substrate, the light-emitting region comprises an anode, an organic functional layer and a cathode; and the lead region is made of an anode And a lead wire connected to the driving chip or the circuit board; the binding area is an area where the lead is connected to the driving chip or the circuit board; and further includes a lead extending area, the end of the lead is located in the lead extending area; and the feature is: located in the light emitting area And a portion between the bonding region constitutes a lead region; a portion between the bonding region and the lower edge of the substrate constitutes a lead extension region; wherein the lead region, the bonding region and the lead extension region are integrally formed on the substrate by a photolithography process And the lead of the lead extension area forms an angle with the lead of the lead area greater than 0° and less than 90°. The organic electroluminescent device according to claim 1, wherein the lead of the lead extension region and the lead of the lead region form an angle of more than 20° and less than 80°. The organic electroluminescent device according to claim 1, wherein the lead of the lead extension region and the lead of the lead region form an angle of 30°, 45°, 60° or 75°. The organic electroluminescent device according to any one of claims 1 to 3, wherein the lead wire is unilaterally bonded, and the lead wires are respectively The odd row leads, the even row leads, the left column leads, the right column leads, the column leads are located in the middle, and the odd row leads and the even row leads are separated on both sides of the column leads. The organic electroluminescent device of claim 4, wherein the left column lead (401 [3]) and the right column lead (401 [4]) of the lead extension region extend away from each other, and not intersect. The organic electroluminescent device of claim 5, wherein the odd row leads (401 [1]) and the even row leads (401 [2]) of the lead extension region extend in opposite directions, and the above The left column lead (401 [3]), the right column lead (401 [4]), the odd row leads (401 [1]), and the even row leads (401 [2]) do not intersect. The organic electroluminescent device of claim 5, wherein the odd row leads (501 [1]) and the even row leads (501 [2]) of the lead extension region extend in a direction away from each other, and The left column lead (501 [3]), the right column lead (501 [4]), the odd row leads (501 [1]), and the even row leads (501 [2]) described above do not intersect. The organic electroluminescent device of claim 4, wherein the left column lead (701[3]) and the right column lead (701[4]) of the lead extension region extend in opposite directions, and intersect. The organic electroluminescent device of claim 8, wherein the odd row leads (701[1]) and the even row leads (701[2]) of the lead extension region extend in opposite directions, and the above The left column lead (701 [3]), the right column lead (701 [4]), the odd row lead (701 [1]), and the even row lead (701 [2]) do not intersect. An organic electroluminescent device as described in claim 8 And wherein the odd row leads (801[1]) and the even row leads (801[2]) of the lead extension region extend away from each other, and the left column lead (801[3]), the right column The leads (801 [4]), the odd row leads (801 [1]), and the even row leads (801 [2]) do not intersect. The organic electroluminescent device according to any one of claims 1 to 3, wherein the lead extension region has fewer leads than the leads of the lead region. The organic electroluminescence device according to any one of claims 1 to 3, wherein the lead extension region has a lead length of 0.1 mm to 0.5 mm. A method for testing an organic electroluminescent device, characterized in that the organic electroluminescent device comprises a substrate, a light-emitting region, a lead region, a binding region, a light-emitting region, a lead region, and a binding region formed on the substrate, and the light-emitting region The anode includes an anode, an organic functional layer, and a cathode; the lead region is formed by a lead connecting the anode and the cathode to the driving wafer or the circuit board; the bonding region is a region where the lead is connected to the driving wafer or the circuit board; and the lead extending region is further included, the lead is The end of the lead is located in the lead extension area; wherein the portion between the light-emitting area and the binding area constitutes a lead area; wherein a portion between the binding area and the lower edge of the substrate constitutes a lead extension area; wherein the lead area, the bonding area and the lead The extension region is integrally formed on the substrate by a photolithography process; The lead of the lead extension region forms an angle with the lead of the lead region greater than 0° and less than 90°. The test method includes the steps of: a) shorting the row lead to be lit, shorting the column lead to be lit; b) making step a The shorted row or column leads get the lighting voltage; and c) the test results are given according to the test conditions. The test method of claim 13, wherein the above step a) shorts all odd row leads, shorts all even row leads, and shorts all column leads. The test method of claim 13, wherein the above step a) shorts all the row leads and shorts all the column leads. The test method according to any one of claims 13 to 15, wherein the above step a) uses a conductive material to connect the leads to be short-circuited. The test method of claim 16, wherein the conductive material is a metal film or a conductive strip.