Disclosed embodiments include an energy directing device having one or more energy relay elements configured to direct energy from one or more energy locations through the device. In an embodiment, surfaces of the one or more energy relay elements may form a singular seamless energy surface where a separation between adjacent energy relay element surfaces is less than a minimum perceptible contour. In disclosed embodiments, energy is produced at energy locations having an active energy surface and a mechanical envelope. In an embodiment, the energy directing device is configured to relay energy from the energy locations through the singular seamless energy surface while minimizing separation between energy locations due to their mechanical envelope. In embodiments, the energy relay elements may comprise energy relays utilizing transverse Anderson localization phenomena.

An optical device (1) includes two prism bodies (41, 42) and four side panels (71-74) attached to both prism bodies (41, 42). A cavity (9) is thereby enclosed. A first reflector (81) can be present at a first side face (81) of the first prism body (41), and a second reflector (82) can be present at a second side face (82) of the second prism body (42). At least one of the prism bodies (41, 42) and/or at least one of the side panels (71-74) can be at least in part made of a non-transparent dielectric material such as a printed circuit board. In some implementations, an optoelectronic component (90) can be attached to the respective constituent of the optical device (1).

A device for measuring solution concentration includes housing, a catadioptric structure, an electromagnetic radiation emitter and an electromagnetic radiation detector. The housing is formed with a detecting part for receiving a solution to be detected. The catadioptric structure is received in the housing, and includes a ray entrance portion, a first total internal reflection part, a second total internal reflection part and a ray exit portion. An accommodation part corresponds to the detecting part. The emitter is disposed at one side of the ray entrance portion, and a ray sequentially passes the ray entrance portion, the detecting part, the solution to be detected, and the first total internal reflection part. Then, the ray is totally internally reflected and converged to the second total internal reflection part, and is reflected again. Finally, the ray passes the ray exit portion and is received by the detector.

A device for measuring solution concentration includes housing, a catadioptric structure, an electromagnetic radiation emitter and an electromagnetic radiation detector. The housing is formed with a detecting part for receiving a solution to be detected. The catadioptric structure is received in the housing, and includes a ray entrance portion, a first total internal reflection part, a second total internal reflection part and a ray exit portion. An accommodation part corresponds to the detecting part. The emitter is disposed at one side of the ray entrance portion, and a ray sequentially passes the ray entrance portion, the detecting part, the solution to be detected, and the first total internal reflection part. Then, the ray is totally internally reflected and converged to the second total internal reflection part, and is reflected again. Finally, the ray passes the ray exit portion and is received by the detector.

An optical element of an embodiment includes an optical element made of a material transparent to light, the optical element including: a back surface facing the front surface; and a connection surface. The front surface includes a recessed surface in a region facing the connection surface. The recessed surface has a point closest to the connection surface as a closest point, and has a first singular point other than the closest point.

Disclosed are a lens for a light-emitting device usable in a display apparatus or a lighting apparatus, and a method of manufacturing a light-emitting device package. The lens may include a lens body including a light-receiving portion provided in a lower surface of the lens body, a light-emitting portion provided on an upper surface of the lens body, and a recess provided at a center of the upper surface of the lens body, and a flat portion provided in a horizontal shape on a bottom surface of the recess perpendicularly to a main emission line of light emitted from a light-emitting device to emit at least a part of light received through the light-receiving portion, upward. A diameter of the flat portion may be 1/100 to 1/10 of an inlet diameter of the light-receiving portion.

Disclosed are relay elements exhibiting transverse localization. The relay elements may include a relay element body having one or more structures, where the structures can be coupled in series, in parallel and/or in stacked configurations. The structures may have multiple surfaces such that energy waves propagating therethrough the relay elements may experience spatial magnification or de-magnification.

Disclosed are a lens for a light-emitting device usable in a display apparatus or a lighting apparatus, and a method of manufacturing a light-emitting device package. The lens may include a lens body including a light-receiving portion provided in a lower surface of the lens body, a light-emitting portion provided on an upper surface of the lens body, and a recess provided at a center of the upper surface of the lens body, and a flat portion provided in a horizontal shape on a bottom surface of the recess perpendicularly to a main emission line of light emitted from a light-emitting device to emit at least a part of light received through the light-receiving portion, upward. A diameter of the flat portion may be 1/100 to 1/10 of an inlet diameter of the light-receiving portion.