Display panels have the advantages of being light and thin, low power consumption, low radiation and the like, and are now widely used in portable electronic products, such as mobile phones, Personal Digital Assistants (PDA) and the like. Examples of display panels are Thin Film Transistor-Liquid Crystal (TFT-LCD) display panels, Organic Light Emitting Diode (OLED) display panels, Low Temperature Poly-silicon (LTPS) display panels, Plasma Display Panels (PDP), etc. A liquid crystal display panel usually includes an array substrate, a color filter substrate and liquid crystal molecules disposed between the array substrate and the color filter substrate. With the rapid development of display technology, the requirements of consumers on the imaging quality of the displays are higher and higher. The requirements of the consumers on the good display effects of the displays are increasingly improved.
In a liquid crystal display device, the aperture ratio refers to the proportion of the area of the portion where light passes by excluding the wiring portion and the transistor portion (generally hidden by a black matrix) of each sub-pixel and the integral area of each sub-pixel. The higher the aperture ratio is, the higher the light passing efficiency is. When the light is emitted by a backlight panel, not all light can penetrate through the panel. For example, signal lines for a source driving chip and a gate driving chip of a liquid crystal display, a thin film transistor (TFT) itself, a storage capacitor used for storing voltage, and the like, such places need to be shaded by a black matrix (black matrix) due to the incomplete transparency of these places and that the light passing by these places is not controlled by the voltage and a correct gray level can not be displayed, so as not to interfere with other transparent areas. The proportion of the effective transparent area to the entire area is referred to as the aperture ratio. In general, in order to ensure the high aperture ratio of the panel to improve the display effect of the panel, no additional device will be arranged in the display area of the panel, thus the devices arranged in the display area of the panel are generally pixel devices related to pixels, while the devices used for detecting the performance of the panel are generally arranged in the non-display area of the panel.