Biological signal measuring device

A biological signal measuring device, comprising:

• a light emitting unit configured to emit light, wherein the light emitting unit includes:
• a first light source configured to irradiate a biological surface of a living body in a first time period;
• and
• a second light source configured to irradiate the biological surface in a second time period;
• and
• a light receiving unit that includes:
• at least one photoreceiver configured to:
• receive scattered light, wherein the light emitted from the light emitting unit is scattered in the living body;
• and
• measure a light intensity signal based on the scattered light, wherein
• the light receiving unit is configured to output biological information related to the living body based on the measured light intensity signal;
• and
• a light reception adjustment mechanism that includes a light receiving area adjustment mechanism, wherein the light receiving area adjustment mechanism includes:
• a first portion that includes an opening;
• and
• a second portion that includes an optical filter configured to prohibit transmission of light of certain wavelength, wherein the first portion is inside the second portion, wherein
• the light receiving area adjustment mechanism is configured to:
• allow the scattered light to pass through the opening in the first portion and block the scattered light at the optical filter in the second portion in the first time period;
• and
• allow the scattered light to pass through both the opening in the first portion and the optical filter in the second portion in the second time period.