A light source device, comprising: an excitation light source providing an excitation light; a wavelength conversion device (150;151;152) located remotely from the excitation light source, including a wavelength conversion material (150;151;152) for converting the excitation light into a converted light; a light introducing device for directing the excitation light onto the wavelength conversion material (150;151;152); and a light collecting device for collecting the converted light from the wavelength conversion material (150;220;310), wherein the light collecting device includes a first reflecting device (240;320) for changing a traveling direction of the converted light, wherein the first reflecting device (240;320) has a hemispherical shape with an inward-facing reflective surface directed towards the wavelength conversion device, wherein the first reflecting device (240;320) has an aperture (422;322), wherein the light introducing device is the aperture in the first reflecting device (240;320), wherein the excitation light from the excitation light source passes through the aperture to illuminate the wavelength conversion material (150,220,310); wherein the light collecting device further includes a light collecting element, wherein a light entrance port of the light collecting element is located at a position near the spherical center of the first reflecting device (240;320), wherein the wavelength conversion device (150;151;152) is disposed such that the focalized illumination point of the excitation light on the wavelength conversion material (150;220;310) is located near the spherical center, at a position symmetrical to the position of the light entrance port with respect to the spherical center, wherein to separate optical paths of the excitation light and the converted light, an etendue of the light introducing device is less than or equal to 1/4 of an etendue of the light collecting device, whereby a loss of the converted light through the light introducing device is reduced. an excitation light source providing an excitation light; a wavelength conversion device (150;151;152) located remotely from the excitation light source, including a wavelength conversion material (150;151;152) for converting the excitation light into a converted light; a light introducing device for directing the excitation light onto the wavelength conversion material (150;151;152); and a light collecting device for collecting the converted light from the wavelength conversion material (150;220;310), wherein the light collecting device includes a first reflecting device (240;320) for changing a traveling direction of the converted light, wherein the first reflecting device (240;320) has a hemispherical shape with an inward-facing reflective surface directed towards the wavelength conversion device, wherein the first reflecting device (240;320) has an aperture (422;322), wherein the light introducing device is the aperture in the first reflecting device (240;320), wherein the excitation light from the excitation light source passes through the aperture to illuminate the wavelength conversion material (150,220,310); wherein the light collecting device further includes a light collecting element, wherein a light entrance port of the light collecting element is located at a position near the spherical center of the first reflecting device (240;320), wherein the wavelength conversion device (150;151;152) is disposed such that the focalized illumination point of the excitation light on the wavelength conversion material (150;220;310) is located near the spherical center, at a position symmetrical to the position of the light entrance port with respect to the spherical center, wherein to separate optical paths of the excitation light and the converted light, an etendue of the light introducing device is less than or equal to 1/4 of an etendue of the light collecting device, whereby a loss of the converted light through the light introducing device is reduced.