Wavelength conversion apparatus, light source system and projection device

The present disclosure relates to a wavelength conversion device, a light source and a projection device. A light conversion region and a light path conversion region are provided on one surface of the wavelength conversion device. The light path conversion region includes a first segment and a second segment. The first segment and the second segment are configured to alternately receive excitation light and respectively guide the excitation light to different preset light paths. The light conversion region is provided with a wavelength conversion material for receiving excitation light emitted from one of the segments, converting the received excitation light into excited light that has at least one wavelength range different from a wavelength of the excitation light, and emitting the excited light.

TECHNICAL FIELD

The present disclosure relates to the field of projection technology, and in particular, to a wavelength conversion device, a light source system and a projection device.

BACKGROUND

This section is intended to provide a background or context to the specific embodiments of the present disclosure depicted in the claims. Although included in this section, the description here is not admitted to be the prior art.

In the field of projection technology, laser light is typically used to excite phosphors so as to generate excited light. A light source is employed to generate excitation light. Scattering powder is used to scatter the excitation light on a wavelength conversion device to convert the excitation light into Lambertian light. The scattered excitation light and the incident excitation light are split by using their different etendue. The realization of light splitting requires area coating, but area coating will cause loss of the excitation light and affect the uniformity of the excitation light.

However, in the case where no area coating is used, it is necessary to separate light paths of the excited light and the excitation light emitted from the wavelength conversion device.

SUMMARY

In view of the above, the present disclosure provides a wavelength conversion device which can effectively separate light paths of excitation light and excited light, and the present disclosure further provides a light source system and a projection device.

A wavelength conversion device is provided. A light conversion region and a light path conversion region are provided on one surface of the wavelength conversion device. The light path conversion region includes a first segment and a second segment. The first segment and the second segment are configured to alternately receive excitation light and respectively guide the excitation light to different preset light paths. The light conversion region is provided with a wavelength conversion material for receiving excitation light emitted from one of the segments, converting the received excitation light into excited light that has at least one wavelength range different from a wavelength of the excitation light, and emitting the excited light.

A light source system is provided. The light source system includes an excitation light source, a first light guiding device, a second light guiding device, a first light splitting-combining element, and the above wavelength conversion device.

The excitation light source is configured to generate the excitation light, and the excitation light is incident to the light path conversion region of the wavelength conversion device.

The light path conversion region is configured to receive the excitation light and alternately emit excitation light propagated along a first preset light path or a second preset light path, where the first preset light path and the second preset light path are separated from each other.

The first light guiding device is configured to guide the excitation light emitted along the first preset light path to the light conversion region of the wavelength conversion device, and to direct the excited light generated by the light conversion region to the first light splitting-combining element.

The second light guiding device is configured to guide the excitation light emitted along the second preset light path to be incident to the first light splitting-combining element.

The first light splitting-combining, element is configured to guide a light beam emitted by the first light guiding device and a light beam emitted by the second light guiding device to exit along a same light path.

A projection device adopting the above light source system is provided.

The wavelength conversion device, the light source and the projection device provided by the present disclosure avoid utilizing area coating to combine the excited light and the excitation light that are emitted from the wavelength conversion device, which reduces the loss of the excitation light and improves the uniformity of emitted light. In addition, the light source system provided by the present disclosure has a compact structure, which reduces the volume of space occupied by the light source system and is beneficial to the miniaturization design of the projection device adopting the light source system.

DESCRIPTION OF SYMBOLS OF MAIN COMPONENTS

The following specific embodiments will further describe the present disclosure in conjunction with the above accompanying drawings.

DESCRIPTION OF EMBODIMENTS

Please refer toFIG. 1andFIG. 2.FIG. 1is a structural schematic diagram of a light source system100according to a first embodiment of the present disclosure.FIG. 2is a top view of a wavelength conversion device170shown inFIG. 1. The light source system100, applied in a projection device, includes an excitation light source110, a first light guiding device130, a second light guiding device150, the wavelength conversion device170, and a first light splitting-combining element180. The excitation light source110is configured to generate excitation light, and the excitation light is incident to the wavelength conversion device170. The wavelength conversion device170rotates in a high speed and alternately emits excitation light propagated along a first preset light path L1or a second preset light pad) L2, where the first preset light path L1and the second preset light path L2are separated from each other. The first light guiding device130is configured to guide the excitation light emitted along the first preset light path L1to a light conversion region173of the wavelength conversion device170, and to direct excited light generated by the light conversion region173to the first light splitting-combining element180. The second light guiding device150is configured to guide the excitation light emitted along the second preset light path L2to be incident to the first light splitting-combining element180. The first light splitting-combining element180is configured to guide a light beam emitted by the first light guiding device130and a light beam emitted by the second light guiding device150to exit along a same light path.

Specifically, the excitation light source110can be a blue light source and emit blue excitation light. It can be understood that the excitation light source110is not limited to the blue light source, and the excitation light source110can also be a ultraviolet light source, a red light source, a green light source, or the like. The excitation light source110includes a light emitting member for generating the excitation light. In the present embodiment, the light emitting member is a blue laser configured to emit a blue laser which serves as the excitation light. It can be understood that the excitation light source110can include one, two or more blue lasers, and the specific number of the blue lasers can be selected according to actual needs.

The wavelength conversion device170includes a substrate171and a driving unit176located at a bottom of the substrate171. The substrate171is driven by the driving unit176to rotate in a high speed around the driving unit176. In the present embodiment, the driving unit176is a motor.

As shown inFIG. 2, a light path conversion region172and the light conversion region173are provided on a top surface of the substrate171. A top surface of the wavelength conversion device170is a circular plane, and the light path conversion region172and the light conversion region173are two concentric annular areas with different radii, in the present embodiment, the light conversion region173has an annular-sector shape and is closer to an edge of the substrate171than the light path conversion region172, that is, a radius of the light conversion region173is larger than that of the light path conversion region172. It can be understood that in other embodiments, the light path conversion region172can be closer to the edge of the substrate171than the light conversion region173, that is, the radius of the light path conversion region172can be larger than that of the light conversion region173.

Specifically, the light path conversion region172includes a first segment172aand a second segment172b, and both the first segment172aand the second segment172bhave an annular-sector shape. In the present embodiment, the first segment172aand the second segment172bare connected. It can be understood that in other embodiments, the first segment172aand the second segment172bare spaced apart from each other.

Further, the light conversion region173and the first segment172ahave a same shape, the light conversion region173and the first segment172aeach are symmetric with respect to a same axis h, and the second segment172bis arranged farther from an gap of annular-sector shape where the light conversion region173is located than the first segment172a.

The first segment172ais provided with a first reflective section, the second segment172bis provided with a second reflective section, and both the first reflective section and the second reflective section are provided with a first reflection surface and a second reflection surface for reflecting the excitation light. The first reflection surface and the second reflection surface are both made of a specular reflection material, such as a high-reflectance metal material including high-reflectance aluminum, silver or the like. In other embodiments, the second reflection surface is a scattering surface, such as a Gaussian scattering surface. When the excitation light is incident to the second reflection surface, the coherency of the scattered excitation light is reduced, and a speckle phenomenon is alleviated. During the high-speed rotation of the wavelength conversion device170, different scattering areas irradiated by the excitation light form different speckle patterns. During the rotation of the second reflection surface, a human eye integral are performed on different speckle patterns to form uniform blue excitation light.

In other embodiments, the light path conversion region172can include three or more segments so as to guide the excitation light to different light paths. For example, the light path conversion region172includes three segments, i.e., a first segment, a second segment and a third segment. The first segment, the second segment and the third segment alternately receive the excitation light emitted from the light source and respectively guide the excitation light to three different preset light paths, that is, the first segment guides the excitation light to a first preset light path, the second segment guides the excitation light to a second preset light path, and the third segment guides the excitation light to a third preset light path. Alternatively, two of the segments guide the excitation light to a same preset light path, and another segment guides the excitation light to another preset light path. For example, the first segment and the second segment guide the excitation light to the first preset light path, and the third segment guides the excitation light to the second preset light path. When the light path conversion region172includes four, five or more segments, the principle is similar to that described above.

Please refer toFIG. 3andFIG. 4in conjunction withFIG. 1.FIG. 3is a sectional view of the wavelength conversion device170show n inFIG. 2taken along a line III-III.FIG. 4is a sectional view of the wavelength conversion device170shown inFIG. 2taken along a line IV-IV. As show n inFIG. 3, the first reflection surface of the first segment172ais parallel to a surface of the substrate171, and the first reflection surface and the second reflection surface are non-coplanar. As shown inFIG. 4, a cross section of the second reflective section of the second segment172bis a right-angled trapezoid, and a hypotenuse of the right-angled trapezoid is a reflection surface. The second reflective section includes one second reflection surface and multiple sidewalls connected to the second reflection surface. The multiple sidewalls are all perpendicular to the surface of the substrate171. The second refection surface is disposed facing away from the substrate171and is not perpendicular to at least one of the multiple sidewalls. The first segment172aand the second segment172bare configured to receive the excitation light. During the high-speed rotation of the wavelength conversion device170, the first segment172aand the second segment172bare alternately located on the light path of the excitation light and then alternately reflect the excitation light to different preset light paths. Specifically, when the first segment172ais located on the light path of the excitation light, the excitation light is reflected by the first segment172ato the first preset light path L1, and is incident to the first light guiding device130; and when the second segment172bis located on the light path of the excitation fight, the excitation light is reflected by the second segment172bto the second preset light path L2, and is incident to the second light guiding device150.

As show inFIG. 2, the light conversion region173is provided with a wavelength conversion material to receive the excitation light emitted from one of the first segment172aand the second segment172b, to convert the received excitation light into excited light having at least one color whose wavelength is different from that of the excitation light, and to emit the excited light. In the present embodiment, the light conversion region173is provided with a red light segment173aand a green light segment173b. The red light segment173ais provided with red phosphor to generate red excited light when being excited by the excitation light, and the green light segment173bis provided with green phosphor to generate green excited light when being excited by the excitation light. In the present embodiment, the red light segment173aand the green light segment173bare identical in shape and size. It can be understood that, in other embodiments. Central angles corresponding to the red light segment173aand the green light segment173bcan be changed according to needs so as to change a ratio of the generated red excited light to the generated green excited light. In addition, in other embodiments, the light conversion region173can be further provided with phosphor having other color to generate excited light having other color. For example, the light conversion region173can be provided with green phosphor and yellow phosphor, alternatively, the light conversion region173is provided with only the yellow phosphor to generate yellow excited light.

Please refer toFIG. 1in conjunction withFIG. 2. The first light guiding device130includes a first reflective element131, a second light splitting-combining element133, and a collection lens group135.

Specifically, the first reflective element131is configured to reflect the excitation light propagated along the first preset light path L1and guide the reflected excitation light to the second light splitting-combining element133. The second light splitting-combining element133is configured to reflect the excitation light and to transmit the excited light. In the present embodiment, the second light splitting-combining element133is provided with a film reflective to blue light and transmissive to yellow light. The collection lens group135is disposed close to the wavelength conversion device170. The collection lens group135converges the excitation light that is emitted from the second light splitting-combining element133and propagated along the first preset light path L1to the light conversion region173. The excited light generated by the light conversion region173is collimated by the collection lens group135, passes through the second light splitting-combining element133, and then is incident to the first light splitting-combining element180along the first preset light path L1. Of course, in other embodiments, the first light guiding device130can not include the collection lens group135, the light emitted from the light splitting-combining element133directly enters the wavelength conversion device170, and the light emitted from the wavelength conversion device170exits after being guided by the second light splitting-combining element133. In other embodiments, the first light guiding device130can include a first module and a second module, the first module is configured to guide the excitation light emitted along the first preset light path L1to the light conversion region173of the wavelength conversion device170, and the second module guides the excited light generated by the light conversion region173to the first light splitting-combining element180. In the case, light propagating along different preset light paths can be guided to their corresponding optical devices by only using the first light guiding device.

The second light guiding device150includes a second reflective element151and a homogenizing element153. The second reflective element151is configured to reflect the excitation light propagated along the second preset light path L2and then to guide the excitation light to the homogenizing element153. The homogenizing element153homogenizes the incident excitation light, guides the excitation light to the first light splitting-combining element180, and adjusts a diameter of the excitation light, such that the excitation light and the excited light that are incident to the first light splitting-combining element180have a same beam diameter, thereby improving the uniformity of the light exiting from the first light splitting-combining element180.

The first light splitting-combining element180is configured to reflect the excitation light and to transmit the excited light. In the present embodiment, the first light splitting-combining element180and the second light splitting-combining element133have a same structure and function.

The light source system100provided in the first embodiment of the present disclosure includes the wavelength conversion device170. The light path conversion region172of the wavelength conversion device170guides the excitation light emitted by the excitation light source110to the first preset light path L1and the second preset light path L2in a time-divisional manner. After passing through the first light guiding device130, the excitation light emitted along the first preset light path L1is incident to the light conversion region173of the wavelength conversion device170, and thus the excited light is generated. After passing through the second light guiding device150, the excitation light emitted along the second preset light path L2is emitted. The light path of the excited light emitted through the first preset light path L1and that of the excitation light emitted through the second preset light path L2are separated from each other, thereby avoiding utilizing area coaling for combining the excitation light and the excited light, reducing the loss of the excitation light and improving the uniformity of emitted light. In addition, the light source system100in the embodiments of the present disclosure as a whole is arranged on the platform of the wavelength conversion device170and has a compact structure, thereby reducing the volume of space occupied by the light source system100and being beneficial to the miniaturization design of the projection device employing the light source system100.

Please refer toFIG. 5, which is a structural schematic diagram of a light source system200according to a second embodiment of the present disclosure. A difference between the light source system200in die present embodiment and the light source system100is that an excitation light source210and a first light guiding device230of the light source system200are respectively provided with a convergent lens212and a convergent lens232that are configured to converge light. Other pans in the present embodiment are the same as those in the first embodiment, and are not repeated herein.

Specifically, the convergent lens212of the excitation light source210is configured to converge the excitation light. The convergent lens212has a relatively long focal length, and the excitation light is still in a converging state after sequentially passing through the convergent lens212and being reflected by a first segment (not shown) of a wavelength conversion device270, and is focused close to a first reflective element231along a first preset light path M1.

The convergent lens232of the first light guiding device230is disposed between the first reflective element231and a second light splitting-combining element233so as to converge the excitation light propagated along the first preset light path M1.

A width of the excitation light beam converged by the convergent lens212is relatively small, and accordingly, a size of the first reflective element231can be arranged to be very small, such that the first preset light path M1and a second preset light path M2have an enough separation space, thereby greatly reducing a possibility of mutual interference and being beneficial to the miniaturization design of the light source system200and the projection device employing the light source system200.

Same as the first embodiment, the light source system200provided in the second embodiment of the present disclosure avoids utilizing area coating to achieve the combination of excitation light and excited light, which reduces the loss of excitation light and improves the uniformity of emitted light. In addition, the light source system200provided by the embodiments of the present disclosure has a compact structure, which reduces the volume of space occupied by the light source system200and is beneficial to the miniaturization design of the projection device employing the fight source system200.

Please refer toFIG. 6, which is a structural schematic diagram of a light source system300according to a third embodiment of the present disclosure. A difference between the light source system300in the present embodiment and the fight source system100in the first embodiment is that the fight source system300includes a supplemental light source320for generating supplemental fight. In addition, a wavelength conversion device370in the present embodiment and the wavelength conversion device170are different in structure. Other parts of the present embodiment are the same as those in the first embodiment, and are not repeated herein. Of course, the present embodiment can be obtained by adding the supplemental light source320and other structures corresponding to the supplemental light source based on the second embodiment.

Please refer toFIG. 7, which is a top view of the wavelength conversion device370shown inFIG. 6. Based on the structure of the wavelength conversion device170, the wavelength conversion device370further includes a transmission region374capable of transmitting light. The transmission region374is filled with anti-reflective glass having a high refractive index. The transmission region374and a light conversion region373are annular areas having a same concentric center and a same radius. The transmission region374and a second segment372bhave a same shape, and each of them is symmetric with respect to a same axis h′.

As shown inFIG. 7, the supplemental fight source320is disposed at a side of the wavelength conversion device370and is configured to generate supplemental light. The supplemental light source320is farther away from a collection lens group335than a fluorescent spot on the wavelength conversion device370. The supplemental light emitted from the transmission region374is incident to a first light splitting-combining element380via the collection lens group335and a second light splitting-combining element333along a first preset light path N1. The supplemental light passes through the transmission region374having a high refractive index, such that an optical path length of the supplemental light passing through the transmission region374is reduced, thereby improving the efficiency of the collection lens group335to collect the supplemental light.

The supplemental light source320includes an LED light source. The supplemental light and the excitation light are of a same color and have different wavelengths. Please refer toFIG. 8, which shows a transmittance curve of the first light splitting-combining element380shown inFIG. 6and a wavelength curve of a light beam incident to the first light splitting-combining element380. In the present embodiment, the excitation light source is a blue laser and emits blue excitation light having a wavelength of 445 nm. The supplemental light source320is a blue LED and emits blue supplemental light having a wavelength ranging from 463 nm to 475 nm. The first light splitting-combining element380and the second light splitting-combining element333are the same in structure and function, and are both configured to reflect the excitation light and to transmit the supplemental light and the excited light.

The supplemental light and the excitation light propagated along a second preset light path N2are combined at the first light splitting-combining element380, which further eliminates the speckle phenomenon of the excitation light emitted by the light source system300.

Same as the first embodiment, the light source system300provided in the third embodiment of the present disclosure avoids utilizing area coating to achieve the combination of excitation light and excited light, which reduces the loss of excitation light and improves the uniformity of emitted light. In addition, the light source system300provided by the embodiments of the present disclosure has a compact structure, which reduces the volume of space occupied by the light source system300and is beneficial to the miniaturization design of the projection device employing the light source system300.

The above is merely embodiments of the present invention, and thus does not limit the patent scope of the present disclosure. Any equivalent structure or equivalent process transformation made by using the description and drawings of the present disclosure, or direct or indirect use of the description and drawings of the present disclosure in other related technical fields shall fall into the patent protection scope of the present disclosure.