Stretchable strain sensor, combination sensor, and display panel and device

A combination sensor, comprising:

• a bio-signal sensor configured to detect a bio-signal;
• a stretchable strain sensor configured to detect a strain caused based on stretching of at least a portion of the stretchable strain sensor;
• and
• a light-emitting element configured to supply light to the bio-signal sensor and the stretchable strain sensor,
• wherein the bio-signal sensor includes a first photo-detective element configured to detect reflected light wherein light supplied from the light-emitting element is reflected by an object of a living body,
• wherein the stretchable strain sensor includes
• an optical structure disposed in a path of light irradiated from the light-emitting element, the optical structure configured to have optical properties that change in response to stretching of at least a portion of the stretchable strain sensor, and
• a second photo-detective element configured to detect light transmitted through the optical structure or reflected by the optical structure.

A display panel, comprising:

• a display area comprising a plurality of first, second, and third sub-pixels, the first, second, and third sub-pixels displaying different colors in relation to one another;
• and
• a stretchable strain sensor in at least one of the first, second or third sub-pixels or adjacent to at least one of the first, second, or third sub-pixels, the stretchable strain sensor being configured to detect a strain caused by stretching of at least a portion of the stretchable strain sensor,
• wherein the first, second and third sub-pixels each include a light-emitting element configured to emit light of a same or different wavelength spectrum from each other, and
• the stretchable strain sensor includes
• an optical structure in a path of light emitted from the light-emitting element, the optical structure configured to have optical properties that change in response to stretching of the portion of the stretchable strain sensor, and
• a photo-detective element configured to detect light transmitted through the optical structure or reflected by the optical structure.