Blood pressure measurement device and method for measuring blood pressure

A blood pressure measurement device, comprising:

• a substrate;
• a protrusion portion, disposed on the substrate and the protrusion portion having a plurality of hollow portions formed within the protrusion portion with each of the plurality of hollow portions being enclosed by the protrusion portion;
• an image sensor, disposed below the substrate and the image sensor corresponding to the hollow portions;
• at least one first light source, disposed below one side of the substrate;
• at least one second light source, disposed below the substrate;
• and
• a control and processing unit, electrically connected to the image sensor, the at least one first light source, and the at least one second light source;
• wherein, the at least one first light source projects a first light toward the substrate, and the first light forms a total reflection inside the substrate;
• when a finger presses the protrusion portion and sinks into the plurality of hollow portions of the protrusion portion to press against the substrate, the total reflection of the first light is destroyed and the first light is reflected by the finger;
• the image sensor receives a reflected first light and captures a bright area image;
• the control and processing unit calculates a number of light-receiving pixels (B) based on the bright area image and a number of light-receivable pixels (A) of the image sensor, to obtain a ratio (B/A) % of the number of light-receiving pixels of the bright area image to the number of light-receivable pixels of the image sensor to determine whether a pressure exerted by the finger is sufficient;
• wherein, the at least one second light source projects a second light toward of the substrate;
• the second light penetrates the substrate and the skin of the finger and is reflected by a blood vessel;
• the image sensor receives a reflected second light and captures a blood vessel volume change image, and the control and processing unit calculates a systolic pressure or a diastolic pressure based on the blood vessel volume change image.