Limited-area reflection type optical sensor and electronic device

An electronic device comprising a limited-area reflection type optical sensor configured to irradiate an object sensing limited area with emitted light from a light emitter and receive reflected light from an object in the object sensing limited area, the optical sensor comprising:

• an emitted light lens or a reflected light lens;
• wherein the emitted light lens comprises:
• an opposite-light-receiver-side portion opposite to a light receiver side constituting a first curvature surface comprising a first curvature while
• a light-receiver-side portion on the light receiver side with respect to the opposite-light-receiver-side portion constitutes a second curvature surface comprising a second curvature smaller than the first curvature in the emitted light lens provided in an optical path of the emitted light;
• wherein the reflected light lens comprises:
• an opposite-light-emitter-side portion opposite to a light emitter side constituting a fourth curvature surface comprising a fourth curvature while
• a light-emitter-side portion on the light emitter side with respect to the opposite-light-emitter-side portion constitutes a fifth curvature surface comprising a fifth curvature smaller than the fourth curvature in the reflected light lens provided in an optical path of the reflected light
• wherein the light emitter comprises a light emitting element configured to emit the emitted light, the light emitting element is arranged such that an optical axis of the emitted light emitted from the light emitting element is located on the opposite-light-receiver side with respect to a center axis of the emitted light lens,
• the light receiver comprises a light receiving element configured to receive the reflected light, and the light receiving element is arranged such that an optical axis of the reflected light in the light receiving element is located on the opposite-light-emitter side with respect to a center axis of the reflected light lens.

An object detection method for determining whether an object exists in an object sensing limited area, the method comprising the steps of:

• a) irradiating the object sensing limited area with emitted light from a light emitter;
• b) receiving reflected light from the object existing in the object sensing limited area in a light receiver;
• and
• c) performing at least one of:
• providing an emitted light lens in an optical path of the emitted light from the light emitter;
• and
• providing a reflected light lens in an optical path of the reflected light from the object sensing limited area to the light receiver;
• wherein the emitted light lens comprises:
• an opposite-light-receiver-side portion opposite to a light receiver side constituting a first curvature surface comprising a first curvature while
• a light-receiver-side portion on the light receiver side with respect to the opposite-light-receiver-side portion constitutes a second curvature surface comprising a second curvature smaller than the first curvature in the emitted light lens provided in an optical path of the emitted light;
• wherein the reflected light lens comprises:
• an opposite-light-emitter-side portion opposite to a light emitter side constituting a fourth curvature surface comprising a fourth curvature while
• a light-emitter-side portion on the light emitter side with respect to the opposite-light-emitter-side portion constitutes a fifth curvature surface comprising a fifth curvature smaller than the fourth curvature in the reflected light lens provided in an optical path of the reflected light,
• wherein the light emitter comprises a light emitting element configured to emit the emitted light, the light emitting element is arranged such that an optical axis of the emitted light emitted from the light emitting element is located on the opposite-light-receiver side with respect to a center axis of the emitted light lens,
• the light receiver comprises a light receiving element configured to receive the reflected light, and the light receiving element is arranged such that an optical axis of the reflected light in the light receiving element is located on the opposite-light-emitter side with respect to a center axis of the reflected light lens.