Methods and systems are provided for a light emitting device. In one example, an illumination system comprises a plurality of light sources, each light source of the plurality of light sources comprising a light emitting diode configured to emit a collimated beam of light of a color, a plurality of reflective optical components oriented identically to one another, wherein the plurality of reflective optical components is configured to direct the first collimated beam, the second collimated beam, the third collimated beam, the fourth collimated beam, and the fifth collimated beam along a common axis, and an output positioned to receive light along the common axis, wherein the output is configured to generate an output beam.

A light-emitting module includes: a plurality of light-emitting elements located on a mounting surface; one or more optical members configured to control light emitted from each of the plurality of light-emitting elements, and allow output light and monitor light for controlling an output of the output light to exit; and a detection unit configured to detect the monitor light. The one or more optical members include a first optical member on which the light emitted from the plurality of light-emitting elements is incident. The plurality of light-emitting elements comprises a plurality of first light-emitting elements, which are, among the plurality of light-emitting elements, all light-emitting elements that are configured to emit light incident on the first optical member. The detection unit includes: a first condensing lens configured to condense the monitor light, and a light-receiving element configured to receive the monitor light exiting from the first condensing lens.

A light-emitting module includes: a plurality of light-emitting elements located on a mounting surface; one or more optical members configured to control light emitted from each of the plurality of light-emitting elements, and allow output light and monitor light for controlling an output of the output light to exit; and a detection unit configured to detect the monitor light. The one or more optical members include a first optical member on which the light emitted from the plurality of light-emitting elements is incident. The plurality of light-emitting elements comprises a plurality of first light-emitting elements, which are, among the plurality of light-emitting elements, all light-emitting elements that are configured to emit light incident on the first optical member. The detection unit includes: a first condensing lens configured to condense the monitor light, and a light-receiving element configured to receive the monitor light exiting from the first condensing lens.

A wavelength conversion member includes a support and a wavelength conversion layer including a first phosphor having a composition represented by Formula (1) and having an emission peak wavelength in a range from 550 nm to 620 nm, and a second phosphor having a different emission peak wavelength and/or a full width at half maximum from the first phosphor. An amount of the first phosphor in the wavelength conversion layer is in a range from 20 mass % to 80 mass % relative to a total amount of the phosphors In Formula (1), M.sup.1 represents at least one of rare earth elements other than La and Ce, a total molar content percentage of Y, Gd, and Lu in M.sup.1 is 90% or more, and p, q, r, and s satisfy 2.7≤(p+q+r)≤3.3, 0≤r≤1.2, 10≤s≤12, and 0<q≤1.2.

A light source device according to an embodiment of the present technology includes: a first light source unit; a polarization split element; a second light source unit; a light synthesis unit; a polarization synthesis element. The first light source unit emits light having a predetermined wavelength band and in an unpolarized state. The polarization split element splits emitted light emitted from the first light source unit into first split light in a first polarization state and second split light in a second polarization state. The second light source unit emits one or more laser beams each having a wavelength band included in the predetermined wavelength band. The light synthesis unit synthesizes the first split light and the one or more laser beams and emits the obtained light as synthesized light in the first polarization state. The polarization synthesis element synthesizes the synthesized light and the second split light.

A light source includes features configured to compensate for discontinuous solid state sources. The light source can produce a wide color gamut in display, and improved color rendering of tissue under observation by phosphor gap filling with colored LEDs. The light source can include provisions to depart from a white light spectrum to heighten differences in anatomical features or functions. The light source can include provisions to introduce narrow-band solid-state sources for producing false-color and pseudo-color images, with variable color rendering to change the power spectral distribution and to compensate for fiber optic length and fiber optic diameter tip sensing.

A light source includes features configured to compensate for discontinuous solid state sources. The light source can produce a wide color gamut in display, and improved color rendering of tissue under observation by phosphor gap filling with colored LEDs. The light source can include provisions to depart from a white light spectrum to heighten differences in anatomical features or functions. The light source can include provisions to introduce narrow-band solid-state sources for producing false-color and pseudo-color images, with variable color rendering to change the power spectral distribution and to compensate for fiber optic length and fiber optic diameter tip sensing.

A light source device according to an embodiment of the present disclosure includes: a light source section including a first light source outputting light in a first wavelength range and a second light source outputting light in a second wavelength range in a same direction as the light in the first wavelength range; a wavelength converter that is excited by the light in the first wavelength range to output fluorescent light; a light condenser that concentrates the light in the first wavelength range and the light in the second wavelength range on the wavelength converter; and a multiplexer that transmits light in the first wavelength range and that reflects at least a portion of the light in the second wavelength range in accordance with incident angles of the light, and combines the light in the first wavelength range, the light in the second wavelength range, and the fluorescent light.

Embodiments of the disclosure are related to a backlight unit and a display device, by disposing a filter reflecting a green light of a long wavelength on a color conversion sheet and disposing a filter reflecting a green light and a red light under the color conversion sheet, a wavelength band of a light supplied to a display panel is controlled and a color reproduction range may be improved while increasing a light efficiency. Furthermore, by disposing a sheet increasing an amount of a vertical light on the color conversion sheet, a wavelength band of a light reflected by a filter disposed on the color conversion sheet is controlled exactly and the backlight unit and the display device capable of a wide color gamut may be provided.

Embodiments of the disclosure are related to a backlight unit and a display device, by disposing a filter reflecting a green light of a long wavelength on a color conversion sheet and disposing a filter reflecting a green light and a red light under the color conversion sheet, a wavelength band of a light supplied to a display panel is controlled and a color reproduction range may be improved while increasing a light efficiency. Furthermore, by disposing a sheet increasing an amount of a vertical light on the color conversion sheet, a wavelength band of a light reflected by a filter disposed on the color conversion sheet is controlled exactly and the backlight unit and the display device capable of a wide color gamut may be provided.