Pixel driving circuit and its driving method, array substrate, transflective display apparatus

A pixel driving circuit, comprising:

• a plurality of pixels arranged in a matrix, each pixel of the pixel driving circuit comprising a transmissive region and a reflective region in which a reflection structure for reflecting the light is provided;
• gate lines located between two adjacent rows of the pixels, at least one of the pixels comprising a light touch module which comprises:
• a photosensitive unit which senses the light intensity and produces an electrical signal carrying the light intensity information;
• a signal reading unit connected with the photosensitive unit, the signal reading unit being controlled by the gate lines, being turned on under the driving of the gate lines, and reading the electrical signal from the photosensitive unit;
• an amplifier connected with the signal reading unit, the amplifier acquiring the electrical signal from the signal reading unit and amplifying the electrical signal;
• a processor connected with the amplifier, the processor being configured to acquire the electrical signal amplified at the current frame from the amplifier, subtract the electrical signal amplified at the current frame from the electrical signal amplified at a previous frame to obtain the change amount of the electrical signal at the current frame relative to the electrical signal at the previous frame, compare the change amount with a threshold of the change of the electrical signal, determine that a touch action occurs and acquire the position information of the pixel where the light touch module is located when the change amount is greater than the threshold of the electrical signal change, and take the position information as the touch position, the threshold of the change of the electrical signal and the electrical signal amplified at the previous frame being stored in the processor,
• wherein, the pixel driving circuit further comprises a common electrode line with which the reflection structure is connected;
• the pixel comprising the light touch module of the pixel driving circuit comprises a first thin film transistor and a first storage capacitor with the reflection structure being a first plate of the first storage capacitor;
• the pixel comprising the light touch module of the pixel driving circuit further comprises a storage electrode which has an overlapping part with the reflection structure, is connected with the drain of the first thin film transistor and is a second plate of the first storage capacitor,
• the storage electrode is located above the reflection structure, and the storage electrode is a transparent electrode so that the incident light can pass through the storage electrode, reach the reflection structure.