Hybrid X-Ray Detection Substrate for MTF and Voltage Balance

The patent combines direct-conversion and indirect-conversion photosensitive devices into a single hybrid detector structure. The direct-conversion layer (e.g., amorphous selenium) provides high resolution for absorbed X-rays, while the indirect-conversion layer (e.g., scintillator material) converts remaining X-rays to visible light for detection. This merging allows the system to achieve high detection resolution through direct conversion while reducing overall energy consumption by utilizing indirect conversion for photons that pass through the direct-conversion layer, thereby resolving the contradiction between resolution and energy use.

The patent segments the photoelectric conversion function into two distinct layers: a direct-conversion layer positioned closer to the X-ray source that maintains high MTF by directly converting X-rays to electrical signals with minimal scattering, and an indirect-conversion layer positioned deeper that operates at lower voltages to convert remaining X-rays. This segmentation allows each layer to optimize its performance characteristics, with the direct-conversion segment preserving MTF and the indirect-conversion segment reducing voltage requirements.

The patent applies partial action by using a relatively thin direct-conversion material layer (e.g., 100-500 μm of amorphous selenium) that absorbs only a portion of the incident X-rays (approximately 30-70% depending on energy and thickness). This partial absorption approach allows the direct-conversion layer to operate at moderate bias voltages while the indirect-conversion layer handles the remaining X-rays, thereby achieving satisfactory overall absorption efficiency without requiring excessively high bias voltages that would be needed if a single thick direct-conversion layer were used.