An organic electroluminescence element (so-called organic EL element) is a light-emitting element having a structure in which at least one layer of a luminous organic layer is interposed between an anode and a cathode. In such a light-emitting element, by applying an electrical field between the cathode and the anode, an electron is injected into a light-emitting layer from the cathode side and also a hole is injected into the light-emitting layer from the anode side, and the electron and the hole are recombined in the light-emitting layer, whereby an exciton is formed, and the energy generated when this exciton is returned to a ground state is emitted as light.
As such a light-emitting element, there is known a light-emitting element which emits light in a near-infrared region exceeding 700 nm (see, for example, JP-A-2000-091073 and JP-A-2001-110570), and recently, the realization of such a light-emitting element which surface-emits light in a near-infrared region as, for example, a light-emitting device such as a light source for biometric authentication for authenticating an individual using biological information such as a vein or a fingerprint, or a near-infrared display for military purposes or the like has been studied.
On the other hand, in a pre-shipment inspection after production of such a light-emitting device, it is necessary to remove a light-emitting device in which a defect such as a dark spot, nonluminescence, or a pixel defect caused by a foreign substance, an air bubble, or the like as a defective product.
In the case of a light-emitting device which emits visible light, in a pre-shipment inspection, by observing the defect by the naked eye while turning on the light-emitting device, it is possible to remove a defective product without using a given inspection apparatus. This means that the correctness of the results of inspection using the given inspection apparatus can be confirmed by the naked eye, and the confirmation of the operation of the given inspection apparatus can be performed by people.
However, in the case of a light-emitting device which emits light in a near-infrared region, the light in a near-infrared region cannot be recognized by the naked eye, and therefore, such a method could not be applied.
One of the objects of the invention is to provide a light-emitting device which can be easily found to be a defective product or not in a pre-shipment inspection, an electronic apparatus including such a light-emitting device, and an inspection method for inspecting whether such a light-emitting device is a defective product or not.
USPTO Backgrounds
USPTO Backgrounds