The present disclosure relates to a wavelength conversion device, and more particularly, to a color wheel device.
A conventional color wheel with reflective phosphor powder includes a substrate coated with a highly reflective layer, and phosphor powder is coated on the highly reflective layer. The highly reflective layer is configured to forwardly reflect the light generated by exciting the phosphor powder with laser. A metal reflective layer, a dielectric multi-layer reflective film, or a metal/dielectric multi-layer reflective film can generally be used as the highly reflective layer.
In general, all materials have their refractive indexes. Therefore, when light passes through two different materials, a scattering loss occurs at the interface between the materials. For example, when an incident light reaches the phosphor powder (n≈1.8) from air (n=0) via the binder medium (n≈1.4 to 1.5) of the phosphor power, about 4-5% of the scattering loss occurs may occur according to the Fresnel law of reflection. If a plurality of films are arranged between the air and the phosphor power, and refractive indexes of the films are gradually increased from the air to the phosphor power in a range between the refractive indexes of the air and the phosphor power, although the scattering loss can be reduced to about 2%, a significant increase in the number of the films will lead to cumbersome coating processes, the decline in the reliability of the films, and significant increase in costs.
In view of the foregoing problem, the present disclosure provides a wavelength conversion device which can effectively reduce the scattering loss of incident light.
According to an embodiment, the present disclosure provides a wavelength conversion device. The wavelength conversion device includes a substrate, a wavelength conversion member, and an anti-reflective structure. The wavelength conversion member is disposed on the substrate. The anti-reflective structure includes a plurality of stacking layers sequentially stacked from the wavelength conversion member. Each of the stacking layers is formed by arranging a plurality of nano particles. Porosities of the stacking layers are gradually increased from a first side of the anti-reflective structure facing towards the wavelength conversion member to a second side of the anti-reflective structure facing away from the wavelength conversion member.
In an embodiment of the present disclosure, equivalent refractive indexes of the stacking layers are gradually decreased from the first side to the second side of the anti-reflective structure.
In an embodiment of the present disclosure, a material of the nano particles includes a silicon-based material.
In an embodiment of the present disclosure, the equivalent refractive indexes of the stacking layers are substantially in a range from 1 to 1.5.
In an embodiment of the present disclosure, a material of the nano particles includes an aluminum-based material.
In an embodiment of the present disclosure, the equivalent refractive indexes of the stacking layers are substantially in a range from 1 to 1.8.
In an embodiment of the present disclosure, the porosities are substantially in a range from 5% to 95%.
In an embodiment of the present disclosure, a thickness of the anti-reflective structure is substantially in a range from 100 nanometers to 10 micrometers.
In an embodiment of the present disclosure, the substrate is reflective.
In an embodiment of the present disclosure, the substrate is transmissive. The wavelength conversion device further includes a dichroic layer disposed between the substrate and the wavelength conversion member.
According to another embodiment, the present disclosure provides a wavelength conversion device. The wavelength conversion device includes a phosphor layer and an anti-reflective structure. The phosphor layer has a first refractive index. The anti-reflective structure is formed by stacking a plurality of nano particles. A material of the nano particles includes a silicon-based material or an aluminum-based material. The anti-reflective structure is configured to receive an excitation light from an incident environment. The excitation light enters the phosphor layer via the anti-reflective structure. The incident environment has a second refractive index. Porosities of the anti-reflective structure are gradually increased from a side of the anti-reflective structure proximal to the phosphor layer to a side of the anti-reflective structure distal to the phosphor layer. A refractive index of the anti-reflective structure is between the first refractive index and the second refractive index.
Accordingly, in the anti-reflective structure of the wavelength conversion device of the present disclosure, the stacking layers sequentially stacked from the wavelength conversion member are formed by arranging the nano particles, and the porosities of the stacking layers are gradually increased from the first side of the anti-reflective structure facing towards the wavelength conversion member to a second side of the anti-reflective structure facing away from the wavelength conversion member. Therefore, the wavelength conversion device of the present disclosure can effectively reduce the scattering loss occurred during the incident light enters the wavelength conversion member from the air by adjusting the density of the nano particles in each of the stacking layers, thereby increasing the whole output brightness of the wavelength conversion device. In addition, the wavelength conversion device of the present disclosure also has advantages of simple manufacturing processes, cheap, and etc.
It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the present disclosure as claimed.
The present disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows:
Reference will now be made in detail to the present embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
Reference is made to
As shown in
In some embodiments, the porosities of the anti-reflective structure 130 are substantially in a range from 5% to 95%. For example, the porosity of the stacking layer 131 closest to the first side 130a is about 5%, and the porosity of the stacking layer 131 closest to the second side 130b is about 95%, but the disclosure is not limited in this regard. The range of the porosities can be adjusted according to actual requirements.
It should be pointed out that if the porosity of a stacking layer 131 is smaller, the incident light entering the stacking layer 131 will be refracted by more nano particles 132, such that the equivalent refractive index of the stacking layer 131 is larger. On the contrary, if the porosity of a stacking layer 131 is larger, the incident light entering the stacking layer 131 will be refracted by less nano particles 132, such that the equivalent refractive index of the stacking layer 131 is smaller. Therefore, because the porosities of the stacking layers 131 are gradually increased from the first side 130a to the second side 130b of the anti-reflective structure 130, equivalent refractive indexes of the stacking layers 131 are gradually decreased from the first side 130a to the second side 130b of the anti-reflective structure 130.
In some embodiments, a material of the nano particles 132 includes a silicon-based material. In some embodiments, the silicon-based material is silicon oxide (SiOx), but the present disclosure is not limited in this regard. In some embodiments, the equivalent refractive indexes of the stacking layers 131 formed by the nano particles 132 including the silicon-based material are substantially in a range from 1 to 1.5. In some embodiments, the wavelength conversion member 120 is a phosphor layer, and the refractive index of the wavelength conversion member 120 is greater than 1.5. Therefore, Owing to the refractive indexes from the air to the wavelength conversion member 120 are arranged in a gradient manner, the scattering loss occurred during the incident light reaches the wavelength conversion member 120 from the air via the anti-reflective structure 130 can be effectively reduced according to the Fresnel law of reflection, such that the whole output brightness of the wavelength conversion device 100 can be increased.
In some embodiments, a material of the nano particles 132 includes an aluminum-based material. In some embodiments, the aluminum-based material is aluminum oxide (AlOx), but the present disclosure is not limited in this regard. In some embodiments, the equivalent refractive indexes of the stacking layers 131 formed by the nano particles 132 including the aluminum-based material are substantially in a range from 1 to 1.8. In some embodiments, the wavelength conversion member 120 is a phosphor layer, and the refractive index of the wavelength conversion member 120 is greater than 1.8. Therefore, Owing to the refractive indexes from the air to the wavelength conversion member 120 are arranged in a gradient manner, the scattering loss occurred during the incident light reaches the wavelength conversion member 120 from the air via the anti-reflective structure 130 can also be effectively reduced according to the Fresnel law of reflection.
From another point of view, the phosphor layer (i.e., the wavelength conversion member 120) has a first refractive index. The anti-reflective structure 130 is formed by stacking a plurality of nano particles 132. A material of the nano particles 132 includes a silicon-based material or an aluminum-based material. The anti-reflective structure 130 is configured to receive an excitation light L from an incident environment (e.g., the air). The excitation light L enters the phosphor layer via the anti-reflective structure 130. The incident environment has a second refractive index. The porosities of the anti-reflective structure 130 are gradually increased from a side of the anti-reflective structure 130 proximal to the phosphor layer to a side of the anti-reflective structure 130 distal to the phosphor layer. A refractive index of the anti-reflective structure 130 is between the first refractive index and the second refractive index.
In some embodiments, a diameter of the nano particles 132 is substantially in a range from 1 nanometer (nm) to 100 nm. Preferably, the diameter of the nano particles 132 can be further in a range from 5 nm to 50 nm, but the present disclosure is not limited in this regard.
In some embodiments, a thickness of the anti-reflective structure 130 is substantially in a range from 100 nm to 10 micrometers (um). Preferably, the thickness of the anti-reflective structure 130 can be further in a range from 100 nm to 5 um, but the present disclosure is not limited in this regard.
As shown in
In some embodiments, the base material 111 of the substrate 110 can be made of glass, metal (e.g., aluminum), ceramic, or a semiconductor material, but the present disclosure is not limited in this regard.
According to the foregoing configurations, it can be understood that the substrate 110 of the embodiment shown in
Furthermore, the substrate 210 is transmissive. As discussed above, the wavelength conversion member 120 can be a phosphor layer and can be excited by light (e.g., laser) to emit light, so as to serve as an emitting layer of the wavelength conversion device 200. Hence, with the structural configurations of the wavelength conversion device 200, light can sequentially passes through the base material 211, the dichroic layer 212, the wavelength conversion member 120, and the anti-reflective structure 130 from the air, and then leave the wavelength conversion device 200 from the anti-reflective structure 130. The dichroic layer 212 is configured to separate a predetermined color light from the incident light, and the predetermined color light can be transformed to another predetermined color light by using the wavelength conversion member 120. That is, the wavelength conversion device 200 of the present embodiment is a transmissive color wheel.
In some embodiments, the base material 211 of the substrate 210 can be made of an inorganic material such as ceramic, quartz, glass, etc., but the present disclosure is not limited in this regard.
Reference is made to
As shown in
Reference is made to
Reference is made to
According to the foregoing descriptions of the embodiments of the present disclosure, it can be seen that in the anti-reflective structure of the wavelength conversion device of the present disclosure, the stacking layers sequentially stacked from the wavelength conversion member are formed by arranging the nano particles, and the porosities of the stacking layers are gradually increased from the first side of the anti-reflective structure facing towards the wavelength conversion member to a second side of the anti-reflective structure facing away from the wavelength conversion member. Therefore, the wavelength conversion device of the present disclosure can effectively reduce the scattering loss occurred during the incident light enters the wavelength conversion member from the air by adjusting the density of the nano particles in each of the stacking layers, thereby increasing the whole output brightness of the wavelength conversion device. In addition, the wavelength conversion device of the present disclosure also has advantages of simple manufacturing processes, cheap, and etc.
Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the present disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims.
Number | Date | Country | Kind |
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201710695261.3 | Aug 2017 | CN | national |
This application claims priority to U.S. Provisional Application Ser. No. 62/465,167, filed Mar. 1, 2017 and China Application Serial Number 201710695261.3, filed Aug. 15, 2017, which are herein incorporated by reference.
Number | Date | Country | |
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62465167 | Mar 2017 | US |