A method for detecting the aging of organic light-emitting diodes based on pure optical detection

Abstract

The present invention relates to a method for detecting the aging of organic light-emitting diodes based on pure optical detection, belonging to the technical field of OLED detection. First, the OLED panel to be tested is placed in a designated test slot, and the OLED panel is powered on, and the current intensity between the positive and negative electrodes of the OLED panel is continuously refreshed, so that the light information emitted by each pixel in the OLED panel to be tested passes through the corresponding filter layer. A photosensitive layer is derived behind the filter layer, and the photosensitive layer is provided with a plurality of photosensitive units, and the photosensitive units are used to collect the optical signals passing through the filter layer. The technology developed by the present invention can ensure accurate detection results, does not affect the structure of the original display board, and has a low destructive effect on the premise of ensuring the production cost and thickness of the OLED panel itself.

Description

Technical Field

[0001] The present invention relates to the technical field of OLED detection, and relates to a detection method and a detection board, specifically an OLED aging detection method and a detection board. Background Art

[0002] OLED (Organic Light-Emitting Diode), also known as organic electroluminescent display and organic light-emitting semiconductor. OLED belongs to a current-type organic light-emitting device, and is a phenomenon of luminescence caused by the injection and recombination of carriers, and the luminescence intensity is proportional to the injected current. Under the action of an electric field in the OLED, holes generated by the anode and electrons generated by the cathode will move, and are respectively injected into the hole transport layer and the electron transport layer, and migrate to the light-emitting layer. When the two meet in the light-emitting layer, energy excitons are generated, thereby exciting the luminescent molecules to finally generate visible light.

[0003] Since the OLED emits light directly from the exciton de-excitation radiation of the light-emitting layer, its greatest advantage is that the contrast and vividness of the OLED screen are superior to those of traditional displays. However, its disadvantage is that since the exciton de-excitation radiation emits photons directly as a light source, the number of excitons will be affected by factors such as the transition of electron holes, resulting in easy aging of the light-emitting layer, the occurrence of the "burn-in" situation, and thus color difference, affecting the use.

[0004] In the processes of detecting, recycling, or providing quality assurance for OLED screens, it is necessary to objectively understand the burn-in situation of the OLED display screen or whether there is burn-in. The current aging detection method generally etches a detection circuit directly on the substrate of the OLED during production. However, the application frequency of this function is relatively low, which will cause waste of the panel thickness space. For example, the invention patent with the authorization announcement number "CN110634432B" discloses: An aging detection method for an OLED pixel circuit, the pixel circuit includes a data writing module, a driving module, a threshold compensation module, a light-emitting unit, a sensing module, and a first light-emitting control module; the driving module includes a control end, a first end, and a second end, and is configured to control the driving current flowing through the first end and the second end to drive the light-emitting unit to emit light; the data writing module is connected to the control end of the driving module and is configured to write a reference voltage to the control end of the driving module during the reset phase, write threshold compensation information to the second end of the driving module during the compensation phase, and write a data signal to the control end of the driving module during the data writing phase; the threshold compensation module is connected to the control end of the driving module and the second end of the driving module, and is configured to store the data signal and couple and adjust the voltage of the second end of the driving module; the light-emitting unit includes a first end and a second end, the first end is connected to the first end of the driving module, and the second end is connected to a second voltage terminal; the sensing module is connected to the first end of the light-emitting unit and an aging detection device, and is configured to write a sensing voltage to the first end and the second end of the light-emitting unit during each reset phase in the display process, sense the aging information of the light-emitting unit during the aging detection process, and transmit the aging information to the aging detection device; the first light-emitting control module is connected to a first voltage terminal and the first end of the driving module, and is configured to conduct the first voltage terminal and the first end of the driving module during the light-emitting phase to write a first voltage to the first end of the driving module. Applying this solution will increase production costs and reduce the application scenarios of the panel.

[0005] Alternatively, directly scan and calculate the aging degree of each pixel. For example, the invention patent publication with the authorization announcement number "CN105139790B" discloses an OLED display aging detection method, including: according to the resolution of the original signal, identifying the first pixels belonging to the original signal from each pixel of the display signal, where the display signal is obtained by performing image interpolation processing on the original signal according to the resolution of the display device; obtaining the aging compensation value of each pixel in the display signal. Among them, detect the first pixels, calculate the aging compensation value of the first pixels, detect the second pixels other than the first pixels, and calculate the aging compensation value of the second pixels according to the aging compensation value of the first pixels through the image interpolation algorithm corresponding to the first pixels adjacent to the second pixels. The result obtained by this algorithm depends on the calculation program, and the detection value of each pixel is inaccurate.

[0006] Since the three primary colors of each pixel in the OLED are independent, although the aging degree of the exciplex in each pixel is related to the actual usage situation, the randomness is relatively large, and errors are likely to occur. Summary of the Invention

[0007] The present invention proposes a method for detecting the aging of organic light-emitting diodes based on pure optical detection, which can ensure accurate detection results, do not affect the structure of the original display panel, and have low destructiveness on the premise of ensuring the production cost and thickness of the OLED panel itself.

[0008] The technical solution of the present invention is as follows:

[0009] A method for detecting the aging of organic light-emitting diodes based on pure optical detection. First, place the OLED panel to be tested in a specified test slot, power on the OLED panel, and continuously refresh the current intensity between the positive and negative electrodes of the OLED panel, so that the light information emitted by each pixel in the OLED panel to be tested passes through the corresponding filter layer, and a photosensitive layer is derived behind the filter layer. The photosensitive layer is provided with a plurality of photosensitive units, and the photosensitive units are used to collect the light signals passing through the filter layer.

[0010] As a further optimization of this solution, an imaging unit is connected to the outside of the photosensitive unit. Each photosensitive unit includes a plurality of photosensors, and each photosensor is optically isolated from all the pixels adjacent to one or more corresponding pixels on the OLED panel to be tested.

[0011] As a further optimization of this solution, each photosensitive unit includes one photosensor, and each photosensor corresponds to one pixel in the OLED panel to be tested.

[0012] As a further optimization of this solution, when powering on the OLED panel, several pixel points are selected as calibration points, and a strong current is applied, and the positions of the calibration points are determined in the photosensitive layer to achieve the alignment of the OLED panel with the filter layer and the photosensitive layer.

[0013] An OLED aging detection board includes a filter layer and a photosensitive layer. The filter layer includes a grating layer and a liquid crystal layer. Electrodes are provided on the liquid crystal layer, which can change the polarization direction of the light beam passing through the liquid crystal layer. The light beam on the side of the grating layer can pass through the liquid crystal layer and the grating layer and shoot towards the photosensitive layer. The photosensitive layer is provided with a plurality of photosensitive units, and each photosensitive unit can convert an optical signal into an electrical signal.

[0014] As a further optimization of this solution, the filter layer includes two grating layers, and the polarization directions of the two grating layers are different. The liquid crystal layer is sandwiched between the two grating layers.

[0015] As a further optimization of this solution, the unit includes a photosensor, which is based on SOI and is a lateral-structured photodiode.

[0016] As a further optimization of this solution, each photosensor includes a substrate, an isolation layer, and a functional layer. The functional layer includes two electrode N regions and P regions, and a multiplication region and an absorption region are provided between the two electrodes.

[0017] As a further optimization of this solution, it further includes a connection layer. The connection layer is used to encapsulate the photosensitive layer and lead out each electrode in the photosensor outside the connection layer for use as other test circuit pins.

[0018] The working principle and beneficial effects of the present invention are as follows:

[0019] Select the OLED panel to be tested, place it in a vacuum environment, remove the outer package, dock the OLED panel with the detection board, and adjust the pixel points to align with the corresponding photosensitive units in the photosensitive layer of the detection board through the filter layer. Different currents are applied to the positive and negative electrodes of the OLED panel, so that the intensity of the optical signal that the primary color points in each element of the OLED panel should output changes continuously. And according to the current signal applied to the OLED panel, the polarization direction of the filter layer in the test board is changed, so that the direction of the light beam shooting towards the photosensitive unit in the detection board is constant. Thus, according to the intensity of the incident light of the photosensitive unit, the output current intensity of the photosensitive unit can be changed to reflect the quality of the output optical signal of the pixel points in the OLED panel. Description of the Drawings

[0020] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0021] Figure 1 It is a flowchart of this application; Detailed implementation mode

[0022] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present invention.

[0023] An OLED aging detection method. First, place the OLED panel to be tested in a specified test slot, power on the OLED panel, and continuously refresh the current intensity between the positive and negative electrodes of the OLED panel, so that the light information emitted by each pixel in the OLED panel to be tested passes through the corresponding filter layer. A photosensitive layer is derived behind the filter layer. The light transmission state of the filter layer can change with the electrical signal state refreshed by the OLED panel to be tested. The photosensitive layer is provided with a plurality of photosensitive units. The photosensitive units are used to collect the light signals passing through the filter layer. An imaging unit is connected outside the photosensitive units. Each photosensitive unit includes a number of photosensors. Each photosensor is optically isolated from all the pixel points adjacent to one or more corresponding pixel points on the OLED panel to be tested. Each photosensitive unit includes one photosensor, and each photosensor corresponds to one pixel point in the OLED panel to be tested.

[0024] One photosensitive unit can cover multiple pixel points, which requires a higher-precision photosensor and can detect multiple pixel points at the same time. When a problem area is detected, a smaller detection board is used to scan the single area.

[0025] For the light-emitting organic material in each pixel point, a gradually changing current is input, and the output light signal is also a gradually changing signal. Therefore, the accurate interval of the spectrum where each pixel has problems can be obtained, which can provide a basis for the later design of the OLED board and the adjustment of the primary color position and area.

[0026] The polarization angle of the filter layer of the detection board can be adjusted. The voltage applied to the filter layer is related to the driving current intensity of the OLED. When the current applied to the light-emitting source in the OLED changes, the direction of the output light signal will also change. If the characteristics of the light signals output by each pixel are the same when the pixel points are normal, the photosensitive units can be normally excited after passing through the filter layer; if the pixel ages, there is a current change interval applied to a certain light source, and the light emission deviates from the normal situation, which will cause the light intensity to weaken when passing through the filter layer processing, resulting in the weakening of the light intensity input to the photosensitive unit and the inability to excite the photosensitive unit.

[0027] When powering on the OLED panel, several pixel points are selected as calibration points, and a strong current is applied. The positions of the calibration points are determined in the photosensitive layer to achieve the alignment of the OLED panel with the filter layer and the photosensitive layer. The size of the filter layer is larger than that of the OLED panel. When placing the OLED panel, the photosensitive unit is aligned with the corresponding pixels of the OLED panel.

[0028] The above functions are for calibrating the positions of the OLED panel and the detection board. Generally speaking, after alignment and calibration, the error is allowed to be about 10% of the pixel points. The light-shielding grating is used to ensure that the light signals of each pixel point do not interfere with those of the adjacent ones.

[0029] Embodiment 2: An OLED aging detection board includes a filter layer and a photosensitive layer. The filter layer includes a grating layer and a liquid crystal layer. Electrodes are provided on the liquid crystal layer, which can change the polarization direction of the light beam passing through the liquid crystal layer. The light beam on the side of the grating layer can pass through the liquid crystal layer and the grating layer and shoot towards the photosensitive layer. The photosensitive layer is provided with a plurality of photosensitive units, and each photosensitive unit can convert the light signal into an electrical signal. The filter layer includes two grating layers, and the polarization directions of the two grating layers are different. The liquid crystal layer is sandwiched between the two grating layers. The unit includes a photosensor, which uses SOI as the substrate and is a lateral-structured photodiode. Each photosensor includes a substrate, an isolation layer, and a functional layer. The functional layer includes two electrode N regions and P regions, and a multiplication region and an absorption region are provided between the two electrodes. It also includes a connection layer, which is used to encapsulate the photosensitive layer and lead out each electrode in the photosensor outside the connection layer for use as pins of other test circuits.

[0030] The settings of the grating layer and the liquid crystal layer in the filter plate can refer to the principle of the LCD screen. Applying a voltage to the liquid crystal layer can adjust the light signal. The photosensitive layer is arranged behind the grating, and the gratings of adjacent photosensitive layers play a role in calibration and filtering. The photosensitive layer adopts a structure with a lateral SOI substrate, which can ensure that the photosensors are completely tiled on the photosensitive layer and correspond to the pixel points of the OLED. Each OLED panel with a certain resolution corresponds to a corresponding detection board. When enough photons enter the absorption region, the carrier concentration between the two electrodes on the functional layer of the photosensor can be increased, thereby reducing the avalanche unit, so the two electrodes can be conducted.

[0031] At the same time, a detection light-emitting board is externally connected to the two electrodes of each photosensitive unit. The detection light-emitting board includes a plurality of pixel points of a single color. Each pixel point is electrically connected to a sensing unit, and a high potential is applied to one end of the sensing unit and one end is connected to a corresponding pixel point of the detection light-emitting board, so that the problem pixels can be directly and intuitively reflected, and the problem pixels with various color changes can be extracted singly.

[0032] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for detecting aging of organic light-emitting diodes based on pure optics, firstly placing the OLED panel to be tested in a designated test slot, characterized in that: The OLED panel is powered on, and the current intensity between the positive and negative electrodes in the OLED panel is continuously refreshed, so that the intensity of the light signal that should be output by the primary color point in each element of the OLED panel is continuously changed, so that the light information emitted by each pixel in the OLED panel to be tested passes through the corresponding filter layer, and the light transmission state of the filter layer can change with the electrical signal state refreshed by the OLED panel to be tested. A plurality of filter units are distributed on the filter layer plane, each of which covers a number of pixel points of the OLED panel, and each of the filter units is surrounded by a grating. The light-isolating grating penetrates the filter layer longitudinally, and a photosensitive layer is derived from the filter layer. The photosensitive layer is provided with a plurality of photosensitive units, and the photosensitive units are used to collect light signals passing through the filter layer. Each of the photosensitive units includes a plurality of photoreceptors, and the electrical indicators of each of the photoreceptors are collected, and the collected electrical indicators are analyzed to obtain the intensity of the light signal received by each photoreceptor, wherein each time the current signal applied to the OLED panel to be tested is refreshed, a group of electrical signal data groups output by the photoreceptors are obtained, and each of the electrical signal data groups is judged.

2. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 1, characterized in that: An imaging unit is connected to the outside of the photosensitive unit, and each of the photoreceptors is optically isolated from all pixel points adjacent to one or more corresponding pixel points on the OLED panel to be tested.

3. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 2, characterized in that: Each of the photosensitive units includes a plurality of photoreceptors, and each photoreceptor corresponds to a pixel point in the OLED panel to be tested.

4. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 1, characterized in that: The size of the filter layer is larger than the size of the OLED panel. When the OLED panel is placed, the photosensitive units are aligned with corresponding pixels of the OLED panel.

5. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 4, characterized in that: When the OLED panel is powered on, several pixel points are selected as calibration points, a strong current is applied, and the position of the calibration points is determined on the photosensitive layer to achieve alignment of the OLED panel with the filter layer and the photosensitive layer.

6. A method for detecting aging of organic light-emitting diodes based on pure optics according to any one of claims 1 to 5, characterized in that: The filter layer includes two grating layers and a liquid crystal layer. The liquid crystal layer is provided with electrodes that can change the polarization direction of the light beam passing through the liquid crystal layer. The polarization directions of the two grating layers are different. The liquid crystal layer is sandwiched between the two grating layers. The light beam on the grating layer side can pass through the liquid crystal layer and the grating layer to project toward the photosensitive layer.

7. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 6, characterized in that: The photosensitive unit comprises a photoreceptor, which is based on SOI and is a photodiode with a lateral structure.

8. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 7, characterized in that: Each of the photoreceptors comprises a substrate, an isolation layer and a functional layer. The functional layer comprises two electrodes, an N region and a P region. A multiplication region and an absorption region are arranged between the two electrodes.

9. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 8, characterized in that: It also includes a connection layer, which is used to encapsulate the photosensitive layer and lead out various electrodes in the photoreceptor on the outer surface of the connection layer to serve as other test circuit pins.

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