Systems and methods to measure pulse and blood oxygen saturation in tissue using pulse oximetry with an ambient light source. Certain pulse oximeters according to various embodiments advantageously do not require and do not include a light source such as an LED, thereby reducing complexity and reducing power consumption.

An organic light-emitting material and the manufacturing method thereof, and an organic light-emitting device are disclosed. The organic light-emitting material includes a benzophenanthrene derivative, which has good planarity and strong visible π-π* absorption ability and has a high quantum yield of blue light-emitting capability as well. Therefore, a benzophenanthrene derivative having a large π-conjugated system has high-efficiency electron transporting properties, and its high electron-withdrawing group increases electron mobility rate and effectively improve the light-emitting efficiency of the organic light emitting device.

An electronic apparatus includes an organic light-emitting device including: a first electrode, a second electrode facing the first electrode, m light-emitting units stacked between the first electrode and the second electrode and including at least one emission layer; and m-1 charge generating layers, each located between two neighboring light-emitting units of the m light-emitting units and including an n-type charge generating layer and a p-type charge generation layer, wherein m is an integer of 2 or more, at least one of the m-1 p-type charge generation layers includes a first doping layer and a second doping layer, the first doping layer includes a first organic material and a first inorganic material, the second doping layer includes a second organic material and a second inorganic material, and the first inorganic material and the second inorganic material are different from each other.

A heterocyclic compound represented by Formula 1 and an organic light-emitting device including the same are provided: ##STR00001## When the nitrogen atom of the acridine moiety is combined (e.g., coupled) with an sp.sub.2 carbon atom of the pentagonal ring, either directly or through a pi-conjugated carbocyclic group, the compound may be electron rich and may easily transport charges. The heterocyclic compound represented by Formula 1 may be used as a delayed fluorescence emitter in the organic light-emitting device, and the device may have a low driving voltage, a high efficiency, a high luminance, and a long lifespan.

An object of the present invention is to provide, as a material for a highly efficient and highly durable organic EL element, an organic compound having excellent properties, including excellent electron-injecting/transporting capability, hole-blocking capability, and high stability in the form of a thin film. Another object of the present invention is to provide a highly efficient and highly durable organic EL element by using this compound. The compound having an azabenzoxazole ring structure of the present invention has excellent heat resistance, and good electron-transporting capability. An organic EL element having an electron-transporting layer, a hole-blocking layer, a light-emitting layer, or an electron-injecting layer including the compound had favorable element characteristics.

Provided is compound of Chemical Formula 1:

##STR00001## wherein: each X.sub.1 is independently N or CH, provided that at least one of them is N; each X.sub.2 is independently N or CH, provided that at least one of them is N; Ar.sub.1 to Ar.sub.4 are each independently a substituted or unsubstituted C.sub.6-60 aryl or a substituted or unsubstituted C.sub.5-60 heteroaryl containing one or more of N, O, and S; Ar.sub.5 is a substituted or unsubstituted C.sub.6-60 aryl or a substituted or unsubstituted C.sub.5-60 heteroaryl containing one or more of N, O, and S; each R.sub.1 is independently hydrogen, deuterium, a substituted or unsubstituted C.sub.1-60 alkyl, a substituted or unsubstituted C.sub.3-60 cycloalkyl, a substituted or unsubstituted C.sub.6-60 aryl, or a substituted or unsubstituted C.sub.5-60 heteroaryl containing one or more of N, O, and S; and n is an integer of 0 to 4,
and an organic light emitting device including the same.

Provided is an organic electroluminescence device, which includes a first electrode and a second electrode which face each other, and a plurality of organic layers between the first electrode and the second electrode, wherein at least one selected from among the organic layers includes a fused polycyclic compound represented by Formula 1 below, thereby exhibiting improved luminous efficiency.

##STR00001##

Provided are a light-emitting device including a condensed cyclic compound represented by Formula 1-1 or 1-2, and an electronic apparatus including the light-emitting device. The light emitting device includes: a first electrode; a second electrode facing the first electrode, and an interlayer between the first electrode and the second electrode and comprising an emission layer, where the interlayer further comprises a hole transport region between the first electrode and the emission layer, the hole transport region comprises a compound represented by Formula 201, a compound represented by Formula 202, or any combination thereof, and the emission layer comprises at least one condensed cyclic compound represented by Formula 1-1 or 1-2.

##STR00001##

An organic compound is described. An organic electroluminescence device comprises the organic compound as a host or a hole blocking layer. The organic compound of the following formula may lower a driving voltage or increases a current efficiency or a half-life of the organic electroluminescence device. ##STR00001##
The same definition as described in the present invention.

A reliable light-emitting element with low driving voltage is provided. The light-emitting element includes an electron-injection layer between a cathode and a light-emitting layer. The electron-injection layer is a mixed film of a transition metal and an organic compound having an unshared electron pair. An atom of the transition metal and the organic compound form SOMO.