Method for detecting aging of organic light emitting diode based on pure optics

Abstract

The invention discloses a method for detecting aging of an organic light-emitting diode based on pure optics, and relates to the technical field of OLED detection, the method comprises the following steps: placing a to-be-tested OLED panel in a specified test slot, electrifying the OLED panel, and continuously refreshing the current intensity between the positive electrode and the negative electrode of the OLED panel, so that light information emitted by each pixel in the to-be-tested OLED panel penetrates through a corresponding light filter layer, and the light information is transmitted to the OLED panel; a photosensitive layer is derived behind the light filtering layer, the photosensitive layer is provided with a plurality of photosensitive units, and the photosensitive units are used for collecting light signals penetrating through the light filtering layer. The technology developed by the invention has the effects of accurate detection result, no influence on the structure of the original display panel and low destructiveness on the premise of ensuring the production cost and the thickness of the OLED panel.

Description

Technical Field

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

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

[0003] Since OLED emits light directly through the de-excitation radiation of excitons in the light-emitting layer, its greatest advantage is that the contrast of OLED screens is better than that of traditional displays. However, its disadvantage is that since the de-excitation radiation of excitons directly serves as the light source, the number of excitons will be affected by factors such as the transition of electron holes, causing the light-emitting layer to age easily and become flaky, resulting in color difference and affecting usage.

[0004] In the process of testing, recycling or quality assurance of OLED screens, it is necessary to objectively understand the burn-in condition of the OLED display screen, or whether burn-in occurs. The current aging detection method is generally to directly etch the detection circuit on the OLED substrate during production, but this function is rarely used and will cause a waste of 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 into the control end of the driving module in the reset phase, write the threshold compensation information into the second end of the driving module in the compensation phase, and write the data signal into the driving module in the data writing phase. The control end of the block; 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 to 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 the second voltage end; the sensing module is connected to the first end of the light-emitting unit and the aging detection device, and is configured to write the sensing voltage into the first end and the second end of the light-emitting unit in each reset stage of the display process, sense the aging information of the light-emitting unit in the aging detection process and transmit the aging information to the aging detection device; the first light-emitting control module is connected to the first voltage end and the first end of the driving module, and is configured to conduct the first voltage end with the first end of the driving module in the light-emitting stage to write the first voltage into the first end of the driving module. Applying this solution will increase production costs and reduce the application scenarios of the panel.

[0005] Or directly scan and calculate the aging degree of each pixel point, such as the invention patent 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 pixel point belonging to the original signal from each pixel point of the display signal, the display signal is obtained by image interpolation processing of the original signal according to the resolution of the display device; obtaining the aging compensation value of each pixel point in the display signal, wherein the first pixel point is detected, the aging compensation value of the first pixel point is calculated, and the second pixel point other than the first pixel point is detected, according to the aging compensation value of the first pixel point, the aging compensation value of the second pixel point is calculated by the image interpolation algorithm corresponding to the first pixel point adjacent to the second pixel point. The result obtained by this algorithm is obtained by relying on the calculation program, and the detection value of each pixel is inaccurate.

[0006] Since the three primary colors of each pixel in OLED are independent, the aging degree of the excimer complex in each pixel is related to practical conditions, but it is also highly random and prone to errors. Summary of the invention

[0007] The present invention proposes a method for detecting aging of organic light-emitting diodes based on pure optics, which can ensure the production cost and thickness of the OLED panel itself, and has the effects of accurate detection results, no influence on the structure of the original display panel, and low destructiveness.

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

[0009] A method for detecting aging of organic light-emitting diodes based on pure optics, firstly placing an OLED panel to be tested in a designated test slot, energizing the OLED panel, and continuously refreshing 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 from the filter layer, and 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.

[0010] As a further optimization of this solution, an imaging unit is connected to the outside of the photosensitive unit, each of the photosensitive units includes a plurality of photoreceptors, 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.

[0011] As a further optimization of the present solution, each of the photosensitive units includes a photoreceptor, and each photoreceptor corresponds to a pixel point in the OLED panel to be tested.

[0012] As a further optimization of this solution, 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 in the photosensitive layer to achieve alignment of the OLED panel with the filter layer and the photosensitive layer.

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

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

[0015] As a further optimization of the present solution, the unit includes a photoreceptor, which is based on SOI and is a photodiode with a lateral structure.

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

[0017] As a further optimization of the present solution, a connection layer is further included, wherein the connection layer is used to encapsulate the photosensitive layer and lead out various electrodes in the photoreceptor to the outer surface of the connection layer to serve as other test circuit pins.

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

[0019] Select the OLED panel to be tested, place it in a vacuum environment, remove the external package, connect the OLED panel to the test board, and adjust the pixel transmittance filter layer to align with the corresponding photosensitive unit in the photosensitive layer of the test board. Apply different currents to the positive and negative electrodes of the OLED panel so that the intensity of the light signal that the primary color point in each element of the OLED panel should output changes continuously. And change the polarization direction of the filter layer in the test board according to the current signal applied to the OLED panel, so that the direction of the light directed to the photosensitive unit in the test board is constant, so that the current intensity output by the photosensitive unit can be changed according to the intensity of the incident light of the photosensitive unit to reflect the quality of the output light signal of the pixel point in the OLED panel. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0021] Figure 1This is a flowchart of the application; DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] An OLED aging detection method, firstly, placing an OLED panel to be tested in a designated test slot, energizing the OLED panel, and continuously refreshing 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 from the 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, the photosensitive layer is provided with a plurality of photosensitive units, the photosensitive units are used to collect light signals passing through the filter layer, an imaging unit is connected to the outside of the photosensitive units, each of the photosensitive units includes a plurality of photoreceptors, 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, each of the photosensitive units includes a photoreceptor, and each photoreceptor corresponds to a pixel point in the OLED panel to be tested.

[0024] One photosensitive unit can cover multiple pixels. This requires higher precision photosensors and can detect multiple pixels at the same time. When a problem area is detected, a smaller detection plate is used to scan the single area.

[0025] For the light-emitting organic material in each pixel, a gradient current is input and the output light signal is also a gradient signal. Therefore, the accurate range of the spectrum where each pixel has problems can be obtained, which can provide a basis for the subsequent design of the OLED panel 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 by the filter layer is related to the driving current intensity of the OLED. When the current applied by the light source in the OLED changes, the direction of the output light signal will also change. If the pixel point is normal, the characteristics of the light signal output by each pixel are the same, so the photosensitive unit can be normally excited after passing through the filter layer; if the pixel ages, there is a current change range applied by a certain light source, and the light emission deviates from the normal, which will cause the light intensity to weaken when processed by the filter layer, so that the light intensity input to the photosensitive unit is weakened and the photosensitive unit cannot be excited.

[0027] When the OLED panel is powered on, several pixel points are selected as calibration points, a strong current is applied, and the calibration point positions are determined on the photosensitive layer to achieve alignment of the OLED panel with the filter layer and the photosensitive layer. The filter layer is larger than the OLED panel, and when the OLED panel is placed, the photosensitive unit is aligned with the corresponding pixel of the OLED panel.

[0028] The above functions are to calibrate the position of the OLED panel and the detection board. Generally speaking, after alignment and calibration, the error is allowed to be around 10% of the pixel. The light shielding grating is to ensure that the light signal of each pixel does not interfere with the adjacent ones.

[0029] Embodiment 2, an OLED aging detection board, comprising a filter layer and a photosensitive layer, wherein the filter layer comprises a grating layer and a liquid crystal layer, the liquid crystal layer is provided with electrodes, which can change the polarization direction of the light beam passing through the liquid crystal layer, and the light beam on the grating layer side can pass through the liquid crystal layer and the grating layer to the photosensitive layer, the photosensitive layer is provided with a plurality of photosensitive units, each of which can convert the optical signal into an electrical signal. The filter layer comprises two layers of the grating layer, the polarization directions of the two layers of the grating layer are different, and the liquid crystal layer is sandwiched between the two layers of the grating layer. The unit comprises a photoreceptor, which is a photodiode with a lateral structure based on SOI. Each of the photoreceptors comprises a substrate, an isolation layer and a functional layer, the functional layer comprises two electrode N regions and P regions, and a multiplication region and an absorption region are provided between the two electrodes. It also comprises a connecting layer, the connecting layer is used to encapsulate the photosensitive layer, and each electrode in the photoreceptor is led out on the outer surface of the connecting layer to be used as other test circuit pins.

[0030] The setting of the grating layer and the liquid crystal layer in the filter plate can refer to the principle of LCD screen. The external voltage of the liquid crystal layer can adjust the light signal. The photosensitive layer is set behind the grating, and the gratings of the adjacent photosensitive layers play the role of verification and filtering. The photosensitive layer uses a lateral SOI substrate structure to ensure that the photoreceptor is completely laid on the photosensitive layer and corresponds 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 area, the carrier concentration between the two electrodes on the functional layer of the photoreceptor can be increased, thereby reducing the avalanche unit, so that the two electrodes can be turned on.

[0031] At the same time, the two electrodes of each photosensitive unit are externally connected to a detection luminous plate, which contains multiple pixels of a single color. Each pixel is electrically connected to a sensing unit, and a high potential is applied to one end of the sensing unit, and the other end is connected to a corresponding pixel of the detection luminous plate, so that the problem pixels can be directly and intuitively reflected, and the problem pixels with multiple color changes can be extracted individually.

[0032] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in 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 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. 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. Each of the filter units is surrounded by a light-isolating grating, which penetrates the filter layer longitudinally. A photosensitive layer is derived from the filter layer, and the photosensitive layer is provided with a plurality of photosensitive units, which are used to collect light signals passing through the filter layer.

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. Each of the photosensitive units includes a plurality of photoreceptors. 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 2, characterized in that: The electrical indicators of each photoreceptor are collected and 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 photoreceptor are obtained, and each of the electrical signal data groups is judged.

5. 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.

6. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 5, 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.

7. A method for detecting aging of organic light-emitting diodes based on pure optics according to any one of claims 1 to 6, 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 two grating layers have different polarization directions. 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.

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

9. The method for detecting aging of organic light-emitting diodes based on pure optics according to claim 8, 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.

10. The method for detecting aging of organic light emitting diodes based on pure optics according to claim 9, 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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