WO2024065695A1

WO2024065695A1 - Polarization light source apparatus

Info

Publication number: WO2024065695A1
Application number: PCT/CN2022/123326
Authority: WO
Inventors: Zhigang Liu; Tao Zhang
Original assignee: Beijing Asu Tech Co.Ltd.
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-04-04

Abstract

A polarization light source apparatus includes a transparent wavelength conversion plate (10, 101, 201, 301, 401), a collimating lens set (20, 103, 203, 303,403), a quarter-wave plate (30, 104, 204, 304, 404) and a reflective polarizing beam splitter (40, 105, 205, 305, 405) along an optical path. The transparent wavelength conversion plate (10, 101, 201, 301, 401) emits an excited light (12, 113, 213, 313, 413) upon receiving an excitation light (11A, 11B, 112, 212, 312, 412). The slow axis of the quarter-wave plate (30, 104, 204, 304, 404) has an approximately 45° angle with the transmission axis of the reflective polarizing beam splitter (40, 105, 205, 305, 405). The excitation light (11A, 11B, 112, 212, 312, 412) can shed onto the transparent wavelength conversion plate (10, 101, 201, 301, 401) from a side proximal or distal to the collimating lens set (20, 103, 203, 303,403). The apparatus further includes a reflective film layer (50, 101a, 201a) and a dichroic mirror (107, 207) in the proximal case, or includes a dichroic film layer (311a, 411a) in the distal case. The transparent wavelength conversion plate (10, 101, 201, 301, 401) optionally includes at least two portions (201M, 201N), which can be adjustably moved to be alternately arranged in the optical path such that the apparatus can alternately generate a different output light.

Description

POLARIZATION LIGHT SOURCE APPARATUS

TECHNICAL FIELD

This present disclosure relates generally to the field of projection display technologies, and more specifically to a polarization light source, and a projection system.

BACKGROUND

The currently three main types of projection display systems include liquid-crystal-display (LCD) projection display systems, liquid-crystal-on-silicon (LCOS) projection display systems, and digital light processing (DLP) projection display systems. Both the LCD and LCOS projection display systems realize the formation of images by modulating the polarization states of light beams emitted from a light source, thereby requiring that the light beams illuminated on their display chips are linearly polarized lights.

A typical light source employed for a projection display system can include an ultra-high-performance (UHP) lamp, a xenon lamp, a light-emitting diode (LED) , a laser-excited phosphor light source, or a laser diode, etc.

Among them, lights emitted by an UHP lamp, a xenon lamp, an LED, and a laser-excited phosphor light source are non-polarized lights. Therefore, in order to apply these non-polarized light sources in the LCD and/or LCOS projection display systems, the non-polarized lights emitted therefrom need to be converted into polarized lights, otherwise only 50%of the light energy is utilized. However, when converting the emitted light beams from non-polarized lights to polarized lights, current technologies typically expand the etendue (i.e. spreading area of angle) of the light beams to twice the original, thereby leading to an increase of the volume of the projection system, an increase of the manufacturing cost, and an energy loss in the process of conversion.

The laser diode is a polarized light source, and it has a high energy utilization rate when applied in the LCD and LCOS projection display systems, but at present the price of a laser diode light source is expensive.

Therefore, in the LCD and LCOS projection display systems, a polarization light source with a relatively high brightness and a moderate price, or a polarization light source having a polarization conversion approach without increasing the optical expansion, is highly needed.

SUMMARY

In order to address the issues associated with existing projection display systems, the present disclosure provides a polarization light source apparatus.

The polarization light source apparatus comprises a transparent wavelength conversion plate, a collimating lens set, a quarter-wave plate and a reflective polarizing beam splitter, which are sequentially arranged along an optical path. The transparent wavelength conversion plate is arranged approximately at a focal plane of the collimating lens set, and is configured, upon receiving an excitation light, to emit an excited light. The collimating lens set is configured to collimate the excited light to thereby generate a collimated excited light. The quarter-wave plate is configured such that a slow axis thereof has an angle of approximately 45° with a transmission axis of the reflective polarizing beam splitter. Herein, a direction of the excitation light can have an angle less than approximately 35°, preferably less than approximately 10°, more preferably less than approximately 5°, and most preferably approximately 0°, with the optical path. As used herein, the term "optical path" is referred to as a travel path of the excited light in the polarization light source apparatus upon its generation in the transparent wavelength conversion plate, which is substantially along an axis that is parallel to the transmission path of the collimated excited light.

Depending on the direction wherein the excitation light sheds onto the transparent wavelength conversion plate, there can be two different scenarios for the polarization light source apparatus according to different embodiments of the disclosure.

In a first scenario for the polarization light source apparatus, the excitation light may shed onto the transparent wavelength conversion plate from a side thereof that is proximal to the collimating lens set. Accordingly, the polarization light source apparatus is further provided with a reflective film layer over a side of the transparent wavelength conversion plate that is distal to the collimating lens set, with a reflective surface of the reflective film layer facing the transparent wavelength conversion plate. Herein, the reflective film layer is configured to reflect at least a portion of the excited light from the transparent wavelength conversion plate back towards the collimating lens set.

In order to facilitate the dissipation of heat that is generated in the transparent wavelength conversion plate when the polarization light source apparatus is in operation, the polarization light source apparatus is optionally further provided with a heat dissipating substrate over a side of the reflective film layer that is distal to the transparent wavelength conversion plate.

Herein optionally, the reflective film layer may be coated onto a surface of the transparent wavelength conversion plate that is proximal to the heat dissipating substrate, and the heat dissipating substrate is further configured to attach onto the reflective film layer-coated transparent wavelength conversion plate for heat dissipation.

Alternatively, the reflective film layer may be coated onto a surface of the heat dissipating substrate that is proximal to the transparent wavelength conversion plate, with a reflective surface thereof facing towards the transparent wavelength conversion plate, and the reflective film layer-coated heat dissipating substrate is further configured to attach onto the transparent wavelength conversion plate for heat dissipation. Herein further optionally, the reflective film layer may be integrated with the heat dissipating substrate to form a single entity. In other words, the heat dissipating substrate is configured to directly attach onto the transparent wavelength conversion plate for heat dissipation, and a surface of the heat dissipating substrate that faces the transparent wavelength conversion plate is configured to be a reflective surface.

Further in the first scenario, the excitation light may derive from a first incident light transmitting from over a side of the collimating lens set that is distal to the transparent wavelength conversion plate through the collimating lens set towards the transparent wavelength conversion plate. As such, in order to separate the input and output lights, the polarization light source apparatus further comprises a dichroic mirror arranged over a side of collimating lens set that is distal to the transparent wavelength conversion plate, and the dichroic mirror is designed to have two different configurations. Under a first configuration, the dichroic mirror is configured to allow a first input light entering into the polarization light source apparatus to reflect thereon to thereby provide the first incident light, and is further configured to allow the excited light or any of its derivatives (i.e. lights deriving from the excited light that pass through any of the following optical components including the collimating lens set, the quarter-wave plate, or the reflective polarizing beam splitter) to transmit therethrough to become a first output light emitting out of the polarization light source apparatus. Under a second configuration, the dichroic mirror is configured to allow a second input light entering into the polarization light source apparatus to transmit therethrough to thereby provide the first incident light, and is further configured to allow the excited light or any of its derivatives (i.e. lights deriving from the excited light that pass through any of the following optical components including the collimating lens set, the quarter-wave plate, or the reflective polarizing beam splitter) to reflect thereon to thereby become a second output light emitting out of the polarization light source apparatus.

Herein regardless of the configuration, the dichroic mirror may be arranged at any one of the following three locations on the optical path: (1) between the collimating lens set and the quarter-wave plate; (2) between the quarter-wave plate and the reflective polarizing beam splitter; or (3) over a side of the reflective polarizing beam splitter that is distal to the quarter-wave plate. Further optionally, the dichroic mirror can be arranged to have an angle of approximately 30-60°, and optionally of approximately 45°, with the optical path.

In the first scenario, the polarization light source apparatus further comprises a first housing which accommodates the above optical components including the transparent wavelength conversion plate, the collimating lens set, the quarter-wave plate, the reflective polarizing beam splitter and the dichroic mirror. The first housing is provided an inlet and an outlet, with the inlet allowing an input light to enter the polarization light source apparatus therethrough, and with the outlet allowing an output light to emit out of the polarization light source apparatus therethrough. In the embodiments where the dichroic mirror has the first configuration, the inlet allows the first input light to enter the polarization light source apparatus therethrough, which is then reflected on the dichroic mirror to thereby provide the first incident light; and the outlet allows the first output light to emit out of the polarization light source apparatus therethrough. In the embodiments where the dichroic mirror has the second configuration, the inlet allows the second input light to enter therethrough to thereby provide the first incident light; and the outlet allows the second output light to emit out of the polarization light source apparatus therethrough. Herein, the first housing may be optionally provided with a reflective inner side surface.

In any of the embodiments of the polarization light source apparatus as described above, the first incident light can optionally comprise a linearly polarized light with a polarization direction thereof substantially parallel with the transmission axis of the reflective polarizing beam splitter, and further optionally, the linearly polarized light is substantially collimated. As such, the first incident light may be derived from an input light provided by a laser diode light source.

In a second scenario for the polarization light source apparatus, the excitation light may shed onto the transparent wavelength conversion plate from a side thereof distal to the collimating lens set. Herein, according to some embodiments of the , the excitation light may derive from a second incident light transmitting from over a side of the transparent wavelength conversion plate distal to the collimating lens set towards the reflective polarizing beam splitter. The polarization light source apparatus may further comprises a dichroic film layer arranged over a side of the transparent wavelength conversion plate distal to the collimating lens set, wherein the dichroic film layer is configured to allow the second incident light to transmit therethrough to thereby provide the excitation light, and to reflect at least a portion of the excited light from the transparent wavelength conversion plate back towards the reflective polarizing beam splitter along the optical path.

Herein optionally, the polarization light source apparatus may further comprise a transparent substrate over a side of the dichroic film layer distal to the transparent wavelength conversion plate, which is configured to allow the second incident light to transmit therethrough.

Similar to the embodiments of the polarization light source apparatus as described above in the first scenario, the polarization light source apparatus in this second scenario can further comprise a second housing, within which the transparent wavelength conversion plate, the collimating lens set, the quarter-wave plate, the reflective polarizing beam splitter are arranged. The second housing is further provided with an inlet, which allowies the second incident light to enter the polarization light source apparatus via the inlet. Further optionally, the second housing can be configured to have a reflective inner side surface.

In the embodiments of the polarization light source apparatus as described above in the second scenario, the second incident light may comprise a non-polarized light, and the second incident light may be provided by a light-emitting diode (LED) light source. Optionally, the second incident light may comprise a polarized light according to certain embodiments.

In any of the embodiments of the polarization light source apparatus as described above, the transparent wavelength conversion plate may optionally be configured to be static, but may optionally be configured to be adjustably move on a plane that is perpendicular to the optical path.

Herein according to some embodiments, the transparent wavelength conversion plate can comprise at least two portions, each comprising a different material selected from a reflective material, a transparent material or a transparent wavelength conversion material. As such, the transparent wavelength conversion plate is configured to adjustably move such that the at least two portions of the transparent wavelength conversion plate are alternately arranged in the optical path so that the polarization light source apparatus alternately generates a different output light.

Herein optionally, the at least two portions of the transparent wavelength conversion plate can be arranged at different fan-shaped regions of a circle or at different sectors of a ring, and the transparent wavelength conversion plate is configured to adjustably rotate around a shaft whose rotating axis is substantially at a center of the circle or of the ring. The transparent wavelength conversion plate can be configured to rotate at a speed of at least 2400 rpm (e.g. 2400 rpm, 3600 rpm, 7200 rpm, 14400 rpm, etc. ) .

Herein, when a certain portion of the transparent wavelength conversion plate comprising a particular transparent wavelength conversion material is arranged in the optical path, a corresponding excited light will be stimulated, and a particular output light will be generated by the polarization light source apparatus. When another portion of the transparent wavelength conversion plate comprising a different transparent wavelength conversion material is arranged in the optical path, a different excited light will be stimulated, and a different output light will be generated by the polarization light source apparatus. When yet another portion of the transparent wavelength conversion plate, which either comprises a reflective material (such as a ceramic reflective material with a rough surface which can scatter an incident light) for the polarization light source apparatus in the above first scenario, or comprises a transparent material for the polarization light source apparatus in the above second scenario, is arranged in the optical path, the output light thus generated by the polarization light source apparatus is substantially the excitation light.

Herein according to some embodiments, the transparent wavelength conversion plate can comprise three portions, which are configured such that the polarization light source apparatus alternately generates three different output lights with three different primary colors, e.g. RGB colors including red (R) , green (G) and blue (B) . There can be different situations.

In a first situation, the three portions may respectively comprise three different transparent wavelength conversion materials which are configured, upon receiving the excitation light, to respectively stimulate three lights with three different primary colors.

In a second situation, two of the three portions may respectively comprise two different transparent wavelength conversion materials configured, upon receiving the excitation light, to respectively stimulate generation of two excited lights with two different colors; and the last one of the three portion comprises one of a transparent material that allows the excitation light to transmit therethrough or a reflective material that allows the excitation light to reflect back therefrom.

Under this second situation, optionally, the excitation light is a blue light, and the two excited lights consists of a green light and a red light. For example, with reference to Table 1 below, the excitation light can be a blue light with a wavelength of 455 nm, and the two different transparent wavelength conversion materials respectively comprises: a first green light-stimulating composition selected from LuAG: Ce ³⁺ or MgAlON∶Mn, and a second red light-stimulating composition selected from YAG: Mn/Mg, CaAlSiN ₃: Eu ²⁺, Sr ₂Si ₅N ₈: Eu ²⁺, or CaAlSiN ₃: Eu ²⁺. In one specific embodiment, the excitation light inputted to the apparatus is a blue light with a wavelength of 455 nm, and the transparent wavelength conversion plate may comprise a first portion comprising a ceramic reflective material or a transparent material which, upon being arranged in the optical path, allows the apparatus to output a blue (B) light. A second portion of the transparent wavelength conversion plate may comprise a transparent ceramic material containing Sr ₂Si ₅N ₈: Eu ²⁺, which can emit a red light with a wavelength of 590-620 mm upon excitation by the blue light, thus when this second portion is arranged in the optical path, the polarization light source apparatus emits a red (R) light. A third portion of the transparent wavelength conversion plate may comprise a transparent ceramic material containing LuAG: Ce ³⁺ (Lu ₃Al ₅O ₁₂: Ce ³⁺) , which can emit a green light with a wavelength of 480-620 nm upon excitation by the blue light, thus when this third portion is arranged in the optical path, the polarization light source apparatus emits a green (G) light.

Further under the above second situation, the excitation light is a blue light, and the two excited lights consists of a yellow light and a red light, and the polarization light source apparatus is further provided with a color filer configured to generate a green light from the yellow light. In the above specific embodiment of the polarization light source apparatus as an example, the third portion of the transparent wavelength conversion plate may alternatively comprise a transparent ceramic material containing YAG: Ce ³⁺ (Y ₃Al ₅O ₁₂: Ce ³⁺) , which can emit a yellow light with a wavelength of 510-630 nm upon excitation by the blue light (445 nm) , and a color filter may be additionally arranged in the optical path of the polarization light source apparatus to thereby allow the apparatus to filter the excited green light to thereby output a green (G) light.

Thus by controllably adjusting that the three portions are alternately arranged in the optical path of the polarization light source apparatus, output of full-color lights can be realized.

In any of the embodiments of the polarization light source apparatus as described above, the collimating lens set may optionally comprise one single convex lens (i.e. biconvex lens) , two plano-convex lenses opposing to each other, or a plurality of convex lenses arranged in an array on a plane that is perpendicular to the optical path. Optionally, the collimated excited light emergent from the collimating lens set towards the reflective polarizing beam splitter has a divergence angle of less than approximately 20° relative to the optical path.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic structure of a polarization light source apparatus provided in the present disclosure;

FIG. 2 shows a schematic structure of a polarization light source apparatus according to a first embodiment of the present disclosure;

FIG. 3A and FIG. 3B respectively show a schematic structure of a polarization light source apparatus according to a second embodiment of the present disclosure, and the ring-shaped transparent wavelength conversion plate;

FIG. 4 shows a schematic structure of a polarization light source apparatus according to a third embodiment of the present disclosure; and

FIG. 5 shows a schematic structure of a polarization light source apparatus according to a fourth embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

In the following, with reference to the drawings that accompany this disclosure, the technical solutions provided in the various embodiments of the disclosure are described in greater detail. It should be noted that the embodiments provided in the disclosure shall be considered to represent only part, but not all, of the embodiments that the present disclosure covers, and thus shall not be considered to impose any limitation on the protection scope of the disclosure. Based on the embodiments provided herein, other embodiments with slight variations in designs, as long as they don’ t depart from the gist of the invention disclosed herein, and can be easily obtained by people of ordinary skills in the art without involving any creative work, shall be considered to be covered by the scope of the disclosure.

In order to address the aforementioned issues that are associated with existing technologies, the present disclosure provides a light source apparatus. Depending on different embodiments, the light source apparatus provided herein can efficiently convert a non-polarized light into a polarized light (see, e.g. Example 3 and Example 4 below) or can efficiently convert a first polarized light into a second polarized light (see, e.g. Example 1 and Example 2 below) , thereby all substantially improving the utilization rate of the light sources that are used in an LCD projection display system and/or a LCOS projection display system.

Specifically, the polarization light source apparatus provided herein is configured, upon receiving an input excitation light, to emit an output excited light that is linearly polarized.

As shown by the schematic diagram of the polarization light source apparatus in FIG. 1, the polarization light source apparatus comprises a transparent wavelength conversion plate 10, a collimating lens set 20, a quarter-wave plate 30 and a reflective polarizing beam splitter 40, which are sequentially arranged along an optical path of the polarization light source apparatus, as illustrated by the bottom-to-top arrow in the figure. Herein, the optical path is substantially along the optical axis (i.e. the rotating symmetrical axis of) of the collimating lens set 20.

The transparent wavelength conversion plate 10 comprises a transparent wavelength conversion material. As used herein, the term “transparent wavelength conversion material” refers to a material that, upon excitation by an excitation light (i.e. stimulating light, such as the excitation light beam 11A and/or 11B illustrated in FIG. 1) , is capable of emitting an excited light (i.e. stimulated light, such as the excited light beams 12 illustrated in FIG. 1) , and is transparent to the excited light. Herein optionally, non-limiting examples of compositions that can be used as the transparent wavelength conversion material for the transparent wavelength conversion plate 10 can include YAG: Ce ³⁺ (Y ₃Al ₅O ₁₂: Ce ³⁺) , LuAG: Ce ³⁺ (Lu ₃Al ₅O ₁₂: Ce ³⁺) , YAG: Mn/Mg, MgAlON∶ Mn, CaAlSiN ₃: Eu ²⁺, Sr ₂Si ₅N ₈: Eu ²⁺, and CaAlSiN ₃: Eu ²⁺, etc. (please refer to Table 1 for more details) . Any one, or any combination, of these above compositions can optionally be processed as a transparent fluorescent ceramic, a fluorescent crystal, or a fluorescent glass, etc., which can further optionally be in a form of a sheet with a thickness of less than 1 mm. Herein, the term “fluorescent ceramics” refers to a ceramic material that is obtained from any one of the fluorescent compositions by means of sintering; the term “fluorescent crystal” refers to a single crystal material that is obtained from any one of the fluorescent compositions by means of crystallization or other process; and the term “fluorescent glass” refers to a glass material that is obtained by sintering any one of the fluorescent compositions together with a transparent glass material.

In order to increase the utility rate of the excited light of the polarization light source apparatus, a reflective film layer 50 can be arranged over a surface of the transparent wavelength conversion plate 10 opposing to the collimating lens set 20 (i.e. over the bottom surface 10A shown in FIG. 1) , which is configured to reflect the portion of the excited light 12 stimulated by the transparent wavelength conversion material in the transparent wavelength conversion plate 10 that travels towards and touches the reflecting surface of the reflective film layer 50 (i.e. the bottom surface of the reflective film layer 50 in FIG. 1) . As used herein, the term “reflective film layer” refers to a layer or a film that can reflect a light, such as the excited light 12 shown in FIG. 1.

According to some embodiments, the reflective film layer 50 may be configured such that it can only reflect but cannot transmit the excited light, such as the reflective film layer 101a in Example 1 and the reflective film layer 201a in Example 2 that are described below. As such, the reflective film layer 50 can be an ordinary reflective film layer (i.e. a film layer having a composition of a metal (e.g. copper, aluminum, silver, gold, etc. ) , an alloy (e.g. copper-aluminum alloy, etc. ) , or of another reflective material (e.g. a multilayer dielectric high-reflection film) ..

According to some other embodiments , the reflective film layer 50 may be specially configured as a dichroic film layer which can reflect the excited light but can also transmit the excitation light, such as the dichroic film layer 311a in Example 3 and the dichroic film layer 411a in Example 4 that are described below. According to some embodiments, the dichroic film layer is configured to transmit a blue light and to reflect a green light. According to some other embodiments, the dichroic film layer is configured to transmit a blue light and to reflect a yellow light. According to yet some other embodiments the dichroic film layer is configured to transmit a blue light and to reflect a red light. There can be other embodiments as well. The materials, structures, and manufacturing method for the dichroic film layer have been disclosed in patent literatures WO2014158802A1, WO1999036814A1, WO1999036805A1, US8927070B2, US3190178A, and US5066098A, whose disclosure is incorporated by reference in their entirety.

Herein, the reflective film layer 50 can optionally be coated onto the surface of the transparent wavelength conversion plate 10 opposing to the collimating lens set 20 (i.e. the bottom surface 10A shown in FIG. 1) , but can optionally be coated onto a top surface of a substrate arranged below the transparent wavelength conversion plate 10 (the substrate is not shown in FIG. 1) .

Herein depending on different embodiments of the polarization light source apparatus, the excitation light can shed or enter into the transparent wavelength conversion plate 10 from different directions.

According to some embodiments, which are described in greater detail in Examples 1 and 2, the excitation light 11A enters or sheds into the transparent wavelength conversion plate 10 in a direction that is opposing to the optical path direction of a collimated excited light 13 (as shown by the top-to-bottom straight-line arrow in the figure) , which may substantially derive from an incident light 15 transmitting from over a side of the collimating lens set 20 that is distal to the transparent wavelength conversion plate 10 through the collimating lens set 20 towards the transparent wavelength conversion plate10. In order to separate the excitation light 11A from the collimated excited light 13, a dichroic mirror (not shown in FIG. 1, yet illustrated as 107 in FIG. 2 and as 207 in FIG. 3A) can be arranged over a side of the reflective polarizing beam splitter 40 that is opposing to the quarter-wave plate 30, and the dichroic mirror is configured to have an appropriate angle with other optical components (i.e. the collimating lens set 20, the quarter-wave plate 30, and the reflective polarizing beam splitter 40, etc. ) of the polarization light source apparatus, such that the excitation light 11A shedding into the polarization light source apparatus can pass through the various optical components (i.e. the reflective polarizing beam splitter 40, the quarter-wave plate 30, and the collimating lens set 20) to enter into the transparent wavelength conversion plate 10 in a direction that is opposite to the optical path of the collimated excited light 13. As used herein, the term “dichroic mirror” refers to a color filter that can selectively reflect certain lights while transmitting others depending on the wavelength of the lights shedding thereto. In the Examples 1 and 2 set forth below, the dichroic mirror is arranged to have an angle of approximately 45° with the optical path of the excited light (or with other optical components, such that the input light (i.e. excitation light) incoming to, and the output light emerging from, the polarization light source apparatus, are configured to have an angle of approximately 90° with each other, as illustrated in FIGS. 2 and 3A shown below. It is noted that the angle between the dichroic mirror and the other optical components is not necessarily set as approximately 45°, but can optionally be any angle bigger than 0° but smaller than 90°depending actual needs.

Herein, the dichroic mirror can have different arrangements, which can be over a side of the reflective polarizing beam splitter 40 that is opposing or distal to the quarter-wave plate 30, or alternatively between the quarter-wave plate 30 and the reflective polarizing beam splitter 40, or alternatively between the collimating lens set 20 and the quarter-wave plate 30. In addition, there can be different configurations for the input light and the output light: optionally the output light can be configured to be along the optical path (i.e. the upward arrow shown in FIG. 1) , and the input light is configured to be perpendicular to the optical path, as such the dichroic mirror is configured to reflect the input light and to transmit the output light; alternatively, the input light can be configured to be oppositely along the optical path, and the output light is configured to be perpendicular to the optical path, as such the dichroic mirror is configured to transmit the input light and to reflect the output light. It is noted that regardless of the configuration, the input light in these embodiments of the polarization light source apparatus is configured to be a collimated and linearly polarized light (with a polarization direction thereof being substantially parallel with the transmission axis of the reflective polarizing beam splitter 40) that can optionally be provided by a laser diode collimated light source, or can optionally be an output light from other optical devices.

In these embodiments of the polarization light source apparatus, a substrate (not shown in this figure) can be provided and arranged below the transparent wavelength conversion plate 10 (i.e. over a side of the transparent wavelength conversion plate 10 opposing to the collimating lens set 20 as well as other optical components such as the quarter-wave plate 30, the reflective polarizing beam splitter 40, etc. ) , and the reflective film layer 50 can be sandwiched between the substrate and the transparent wavelength conversion plate 10. Preferably, the substrate can be a heat dissipation substrate, as illustrated in Examples 1 and 2.

According to some other embodiments, which are described in greater detail in Examples 3 and 4, the excitation light 11B enters or sheds into the transparent wavelength conversion plate 10 in a direction that is parallel to the optical path direction of a collimated excited light 13 (as shown by the bottom-to-top arrow in the figure) . In these embodiments, no dichroic mirror is needed, and the reflective film layer 50 can be further configured to be able to transmit the excitation light 11B, in addition to reflecting the excited light 12. It is noted that in these embodiments, the reflective film layer 50 is substantially a dichroic film layer, and non-limiting examples may include a film layer that is transmissive to a blue light but reflective to a green light, a film layer that is transmissive to a blue light but reflective to a yellow light, or a film layer that is transmissive to a blue light but reflective to a red light, etc. In these embodiments of the polarization light source apparatus, a transparent substrate (not shown in this figure) can be provided and arranged below the transparent wavelength conversion plate 10 (i.e. over a side of the transparent wavelength conversion plate 10 opposing to the collimating lens set 20 as well as other optical components such as the quarter-wave plate 30, the reflective polarizing beam splitter 40, etc. ) , and the reflective film layer 50 can be sandwiched between the substrate and the transparent wavelength conversion plate 10, as illustrated in Examples 3 and 4.

The excited light 12 emitted from the transparent wavelength conversion plate 10 is a non-polarized light. By means of the reflective film layer 50 and the collimating lens set 20, the non-polarized excited light 12 can be collected and collimated such that the divergence angle of the collimated excited light 13 is less than approximately 20° (herein, the divergence angle is defined relative to the optical axis (Y-axis) , which can be ± 20°) , and then the collimated excited light 13 successively passes through the quarter-wave plate 30 and the reflective polarizing beam splitter 40 to become the output excited light of the polarization light source apparatus.

As used herein, the term “collimating lens set” refers to an optical lens set by which the light beams can be collimated or converged. A collimating lens set as used herein can comprise one lens or a plurality of lenses arranged in an array. Furthermore, the transparent wavelength conversion plate 10 can be arranged at approximately a focal plane of the collimating lens set 20.

In the polarization light source apparatus, it is further configured such that the angle between the slow axis of the quarter-wave plate 30 and the transmission axis of the reflective polarizing beam splitter 40 is configured to be approximately 45°.

As used herein, the term “quarter-wave plate” refers to a waveplate which is the quarter-wave plate with reference to the wavelength of the exited light. A quarter-wave plate can convert a linearly polarized light beam into a circularly polarized light beam, and vice versa. Herein, an original linearly polarized light beam can, after passing through a quarter-wave plate whose slow axis is arranged to be at an angle of approximately 45° with the polarization direction of the linearly polarized light beam, become a circularly polarized light beam; and the circularly polarized light beam that is reflected back and is then allowed to once again pass through the quarter-wave plate can become a linearly polarized light beam whose polarization direction substantially rotates by 90° compared with the original linearly polarized light beam.

The term “reflective polarizing beam splitter” refers to a polarizer that allows certain components in a light beam having a polarization direction that is substantially parallel with the transmission axis (i.e. optical axis) of the polarizer to pass through while reflecting other components of the light beam. As such, when a non-polarized light passes through the polarizer (i.e. the reflective polarizing beam splitter) , it is divided or splitted into a transmitted light and a reflective light: the transmitted light has a polarization direction thereof that is substantially parallel with the transmission axis of the polarizer, and the reflected light has a polarization direction thereof that is substantially perpendicular to the transmission axis of the polarizer.

The polarization state of a non-polarized light beam, such as the collimated excited light 13 that passes through the collimating lens set 20, remains unchanged after passing through the quarter-wave plate.

A first portion of the light beam 13 whose polarization direction is substantially same as, or is substantially parallel with, the transmission axis of the reflective polarizing beam splitter 40 (i.e. “polarizer” ) passes through the reflective polarizing beam splitter 40 and becomes a first output light.

A second portion of the light beam 13 whose polarization direction is substantially perpendicular to the transmission axis of the reflective polarizing beam splitter 40 is reflected back to the quarter-wave plate 30, and further becomes a circularly polarized light beam after passing through the quarter-wave plate 30. The circularly polarized light beam continues to pass through the collimating lens set 20 and the transparent wavelength conversion plate 10, is reflected by the reflective film layer 50, and then returns back to the quarter-wave plate 30 in the original optical path. After passing through the quarter-wave plate 30, the circularly polarized light beam becomes a linearly polarized light beam whose polarization direction substantially rotates by 90° compared with the original linearly polarized light beam (i.e. the second portion of the light beam 13) . Since the polarization direction of the linearly polarized light beam is substantially parallel with the transmission axis of the polarizer 40, it can pass through the polarizer 40, and become a second output light. The second output light then combines with the first output light to become the output light 14 of the polarization light source.

As such, by means of the polarization light source provided herein, a non-polarized light emitted by a light source is substantially converted into a polarized light without increasing the luminous area of the light source.

In the following, a total of four specific examples, which represent four different embodiments of the polarization light source, are provided in more detail.

Example 1:

In this specific example, a first embodiment of the polarization light source apparatus is provided below, which is illustrated in FIG. 2.

As shown in the figure, the polarization light source apparatus according to this first embodiment 001 substantially comprises a transparent wavelength conversion plate 101, a collimating lens set 103, a quarter-wave plate 104, a reflective polarizing beam splitter 105 and a dichroic mirror 107, which are arranged in a housing 108 for the polarization light source apparatus 001.

The housing 108 is provided with two openings (i.e. a first opening 106 and a second opening 109 shown in the figure) , which are configured as an inlet for an incoming/incident light (i.e. incident excitation light 112) and an outlet for an emergent lights (i.e. output light 114) , respectively. In the specific embodiment of the polarization light source apparatus 001 shown in FIG. 2, the first opening 106 is configured as the inlet for incoming light 112 (i.e. the light source apparatus inlet) , and the second opening 109 is configured as the outlet for the emergent light 114 (i.e. the light source apparatus outlet) . It is noted that according to another embodiment of the polarization light source apparatus 001 (not shown) , the second opening 109 is configured as the inlet for incoming lights (i.e. the light source apparatus inlet) , and the first opening 106 is configured as the outlet for emergent lights (i.e. the light source apparatus outlet) .

In the following, the specific configuration and the working mechanism of the various optical components in the polarization light source apparatus are described in detail with the embodiment shown in FIG. 2 only, i.e. the first opening 106 and the second opening 109 are configured as the inlet for incoming lights (i.e. the light source apparatus inlet) and the outlet for emergent lights (i.e. the light source apparatus outlet) , respectively.

Specifically, within the housing 108 of the polarization light source apparatus 001, the transparent wavelength conversion plate 101, the collimating lens set 103, the quarter-wave plate 104, the reflective polarizing beam splitter 105, and the dichroic mirror 107 are arranged in a sequential order towards the second opening 109 of the housing 108, as illustrated by the Y-Axis that is substantially parallel with a direction of the emergent lights emitting out through the second opening 109.

Herein, optionally, each of these above optical elements (i.e. the transparent wavelength conversion plate 101, the collimating lens set 103, the quarter-wave plate 104, the reflective polarizing beam splitter 105, and the dichroic mirror 107) can be fixedly arranged in the housing 108. Such a fixed configuration can be realized by various means. For example, each of the optical elements is fixedly attached onto the housing 108 by means of a connector 110 mounted at a fixed position of an inner wall of the housing 108, as illustrated in FIG. 2. In another example, each of the optical elements can be fixedly attached onto the inner wall of the housing 108 by means of an adhesive. In yet another example, each of the optical elements can be fixedly mounted into a groove in the inner wall of the housing 108. Other connection means are also possible.

Herein, the transparent wavelength conversion plate 101 comprises a transparent wavelength conversion material. As in this specific example, the transparent wavelength conversion material used in the transparent wavelength conversion plate 101 is a transparent fluorescent ceramics YAG: Ce ³⁺ (Y ₃Al ₅O ₁₂: Ce ³⁺) , and the transparent wavelength conversion plate 101 has a thickness of approximately 0.5 mm, a length of approximately 4 mm, and a width of approximately 4 mm (i.e. 4 mm x 4 mm x 0.5 mm) . Yet it is noted that the transparent wavelength conversion material may optionally comprise yet another composition (i.e. another transparent fluorescent ceramics, a fluorescent glass, or a fluorescent crystal) , and the transparent wavelength conversion plate 101 may be of a different dimension or size. Non-limiting examples of materials that can be used as the transparent wavelength conversion material can optionally be selected from any of the compositions listed in Table 1.

Table 1. Examples of transparent wavelength conversion materials and certain properties

The lower surface of the transparent wavelength conversion plate 101 (i.e. the surface of the transparent wavelength conversion plate 101 that is opposing to the second opening 109 of the housing 108) is coated with a reflective film layer 101a, configured such that a reflecting surface thereof faces the second opening 109. Herein, the reflective film layer 101a can preferably have a high reflective rate to a light having a wavelength between approximately 420 nm and 660 nm. As used herein, the term “high reflective rate” is defined as no less than 90%(i.e. ≥ 90%)

The transparent wavelength conversion plate 101 can optionally be configured to attach onto a heat dissipation substrate 102, which can be realized by means of a heat-resistant adhesive, by high temperature welding, or by clamping, etc. As such, the heat generated during operation of the polarization light source apparatus 001 can be effectively dissipated by the heat dissipation substrate 102 to thereby favorably increase the service life of the polarization light source apparatus 001. The heat dissipation substrate 102 can be made of a material with high thermal conductivity, such as the metal copper, aluminum, steel, etc., but can also be made of other materials, such as an alloy (e.g. a copper-aluminum alloy, etc. ) . As in this specific example, the dimension of the heat dissipation substrate 102 is approximately 20 mm x 20 mm x 4 mm (length x width x thickness) , but can be of a different size.

The transparent wavelength conversion plate 101 is arranged to be approximately at the focal plane of the collimating lens set 103, such that excited lights 113 emitted by the wavelength conversion material contained in the transparent wavelength conversion plate 101 can be effectively collimated by the collimating lens set 103. As in this specific example, the collimating lens set 103 comprises one single convex lens (i.e. biconvex lens) , but can optionally comprise two plano-convex lenses opposing to each other, or comprise a plurality of convex lenses that are arranged in an array on a plane that is perpendicular to the optical path of the lights.

The quarter-wave plate 104 and the reflective polarizing beam splitter 105 can be arranged such that an angle between the slow axis of the quarter-wave plate 104 and the transmission axis of the reflective polarizing beam splitter 105 is approximately 45°.

The dichroic mirror 107 is configured to reflect the incoming/incident light (i.e. excitation light) 112 incoming from the first opening 106 (i.e. the light source apparatus inlet) and to transmit the excited light 113 therethrough. In this specific example of the polarization light source apparatus 001, the dichroic mirror 107 is arranged to have an angle of approximately 45° with other optical elements (i.e. the collimating lens set 103, the quarter-wave plate 104, and the reflective polarizing beam splitter 105, etc. ) , and such an arrangement allows the incident excitation light 112 to enter into the polarization light source apparatus 001 in a direction that is perpendicular to the optical path of the excited light 114 (i.e. the optical axis of the collimating lens set 103) . It is noted that the dichroic mirror 107 can optionally be arranged to have an angle other than 45° with other optical elements.

Herein, the incident excitation light 112 is configured to be a collimated light beam and is further configured to be a linearly polarized light with a polarization direction thereof being substantially parallel with the transmission axis of the reflective polarizing beam splitter 105. As such, the incident excitation light 112 may optionally be provided by a laser diode collimated light source, or may optionally be an output light from other optical devices. The excited light 113 is a non-polarized light. The emergent/output light 114 that is emitted from the polarization light source apparatus 001 is a linearly polarized light, and its polarization direction is substantially parallel with the transmission axis of the reflective polarizing beam splitter 105. As in this specific example, the excitation light 112 is a blue light having a wavelength of approximately 420 nm –470 nm, and the excited light 113 is a yellow light having a wavelength of approximately 500 nm –660 nm. Yet the excitation light 112 and the excited light 113 may have a different wavelength according to other embodiments of the polarization light source apparatus.

The working mechanism for the above embodiment of the polarization light source apparatus 001 is as follows:

The incident excitation light 112 enters into the interior of the polarization light source apparatus 001 from the light source apparatus inlet (i.e. the first opening 106) , and turns its travel direction by 90° after being reflected by the dichroic mirror 107. The excitation light 112 then successively passes through the reflective polarizing beam splitter 105 and the quarter-wave plate 104, and is further converged by the collimating lens set 103 onto the transparent wavelength conversion plate 101. Upon excitation, the excitation wavelength conversion material contained in the transparent wavelength conversion plate 101 then emits an excited light 113.

The excited light 113 is a non-polarized light. Part of the excited light 113 may travel upward (i.e. in a direction towards the light source apparatus outlet or the second opening 109) to reach the collimating lens set 103, and part of the excited light 113 may travel downward (i.e. in a direction opposing the light source apparatus outlet or the second opening 109) to reach the reflective film layer 101a arranged on the lower surface of the transparent wavelength conversion plate 101, so as to be reflected upward again (i.e. in a direction towards the second opening 109) to further reach the collimating lens set 103.

After being collimated by the collimating lens set 103, the excited light 113 passes through the quarter-wave plate 104, and the non-polarized light remains non-polarized after passing through the quarter-wave plate 104. A first portion of the non-polarized light whose polarization direction is substantially parallel with the transmission axis of the reflective polarizing beam splitter 105 is able to pass through the reflective polarizing beam splitter 105 and the dichroic mirror 107 and is then emitted from the light source apparatus outlet 109 to become a first output light beam. A second portion of the non-polarized light whose polarization direction is perpendicular to the transmission axis of the reflective polarization beam splitter 105 is reflected back to the quarter-wave plate 104, and successively passes through the collimating lens set 103 and the transparent wavelength conversion plate 101, and is then reflected by the reflective film layer 101a. The reflected beam then returns in the original optical path and direction (i.e. upward towards the second opening 109) , and after passing through the quarter-wave plate 104, the polarization direction of this reflected beam rotates by 90°. At this time, because this reflected beam has a polarization direction that is substantially parallel with the transmission axis of the reflective polarizing beam splitter 105, it will pass through the reflective polarizing beam splitter 105, and then after passing through the reflective polarizing beam splitter 105 and the dichroic mirror 107, it will be emitted out from the light source outlet 109 to become a second output light beam, which substantially combines with the first out light beam to thereby become the light source output light beam 114.

In addition to the specific embodiment of the polarization light source apparatus as illustrated in FIG. 2 and described above, there can be other variations according to different embodiments.

According to certain variant embodiment (not shown) , the polarization light source apparatus has substantially same arrangement for each of the components (i.e. the transparent wavelength conversion plate 101, the collimating lens set 103, the quarter-wave plate 104, the reflective polarizing beam splitter 105, the dichroic mirror 107, and the housing 108) of the aforementioned embodiment of the polarization light source apparatus as illustrated in FIG. 2. In opposing contrast, however, the first opening 106 and the second opening 109 in the housing 108 are respectively configured as the outlet for an emergent light (i.e. the light source apparatus outlet) and the inlet for an incident excitation light (i.e. the light source apparatus inlet) , respectively. Correspondingly, the dichroic mirror 107 in this embodiment of the polarization light source apparatus is configured to transmit the incoming/incident light (i.e. excitation light) incoming from the second opening 109 (i.e. the light source apparatus inlet) therethrough and to reflect an excited light thereon to allow it emerge out through the first opening 106 (i.e. the light source apparatus outlet) . It is further noted that in a manner same as the embodiment as illustrated in FIG. 2, the incident excitation light in this embodiment is similarly configured to be a collimated and linearly polarized light (with a polarization direction thereof being substantially parallel with the transmission axis of the reflective polarizing beam splitter 105) that can optionally be provided by a laser diode collimated light source, or can optionally be an output light from other optical devices.

According to certain other variant embodiments (not shown) , the polarization light source apparatus also comprises each of the components (i.e. the transparent wavelength conversion plate 101, the collimating lens set 103, the quarter-wave plate 104, the reflective polarizing beam splitter 105, the dichroic mirror 107, and the housing 108) of the aforementioned embodiment of the polarization light source apparatus as illustrated in FIG. 2 and has similar configurations for these components, yet the arrangement for the dichroic mirror 107 and the corresponding first opening 106 is different from the embodiment illustrated in FIG. 2, which can be alternatively arranged between the collimating lens set 103 and the quarter-wave plate 104, or can be alternatively arranged between the quarter-wave plate 104 and the reflective polarizing beam splitter 105. It is noted that in these embodiments, the first and

second openings

106 and 107 can optionally serve as the inlet and outlet respectively, or optionally serve as the outlet and inlet respectively, for the polarization light source apparatus.

Example 2:

Example 2 represents a second embodiment of the polarization light source apparatus. As illustrated by the schematic diagram shown in FIG. 3A, this second embodiment of the polarization light source apparatus is substantially a variant of the first embodiment of the polarization light source apparatus (i.e. Example 1) as described above.

In a configuration similar to the first embodiment of the polarization light source apparatus 001 as illustrated in FIG. 2 and as described above in Example 1, as shown in FIG. 3A, this second embodiment of the polarization light source apparatus 002 substantially also comprises a transparent wavelength conversion plate 201, a collimating lens set 203, a quarter-wave plate 204, a reflective polarizing beam splitter 205 and a dichroic mirror 207, which are arranged in a sequential order towards a second opening 209 of a housing 208, as illustrated by the Y-Axis that is substantially parallel with a direction of the emergent lights emitting out through the second opening 209. The housing 208 is also provided with a first opening 206, which serves as the light source apparatus inlet for an incident excitation light 212, and is further provided with a second opening 209, which serves as the light source apparatus outlet for an output/emergent light 214. An angle between the slow axis of the quarter-wave plate 204 and the transmission axis of the reflective polarizing beam splitter 205 is approximately 45°. The configuration of each of the above optical components, and the working mechanism of the light source apparatus as well, is similar to, and can thus be referenced to, Example 1 as described above, and the description thereof is therefore skipped herein.

The difference between the first embodiment 001 and the second embodiment 002 of the polarization light source apparatus is that the transparent wavelength conversion plate 201 in this second embodiment 002 has an annular shape (or a ring shape) and can comprise more than one transparent wavelength conversion material. In one illustrating example as shown in FIG. 3B, the transparent wavelength conversion plate 201 substantially comprises two portions: a first portion 201M and a second portion 201N, which respectively comprise a first transparent wavelength conversion material and a second transparent wavelength conversion material. In other examples, the transparent wavelength conversion plate 201 may optionally comprise more than two portions, each comprising a different transparent wavelength conversion material. Herein each different transparent wavelength conversion material is configured, upon excitation by a same excitation light, to be able to emit a different excited light (i.e. with a different wavelength) . As in this specific example, the transparent wavelength conversion plate 201 has a thickness of 0.5 mm, and the annular shape of the transparent wavelength conversion plate 201 has an inside diameter of 16 mm and an outside diameter of 20 mm. Furthermore, the first portion 201M of the transparent wavelength conversion plate 201 has a composition of a first transparent fluorescent ceramics LuAG: Ce ³⁺, which can emit green lights upon excitation by an incident blue light; the second portion 201N of the transparent wavelength conversion plate 201 has a composition of a second transparent fluorescent ceramics YAG: Mn/Mg, which can emit red lights upon excitation by the incident blue light. Yet it is noted that this above represents only one illustrating example, and shall not be interpreted to impose any limitation to the dimension and/or the compositions of the transparent wavelength conversion plate 201.

As shown in FIG. 3A, the lower surface of the transparent wavelength conversion plate 201 (i.e. the surface of the transparent wavelength conversion plate 201 that is opposing to the second opening 209 of the housing 208) is similarly coated with a reflective film layer 201a, configured such that a reflecting surface thereof faces the second opening 209. Furthermore, the ring-shaped transparent wavelength conversion plate 201 is fixedly attached onto a heat dissipation substrate 202, which is mounted on a rotating shaft 210. The rotating shaft 210 is operably connected with a driving motor (not shown) that is fixedly attached onto the light source housing 208, and is configured to rotate around a rotating axis that is substantially parallel with the direction of the emergent lights emitting out through the light source apparatus outlet ( (i.e. the second opening) 209, as illustrated by the Y-Axis. When the light source apparatus works, the rotating shaft 210 drives the heat dissipation substrate 202 and the transparent wavelength conversion plate 201 to rotate at a pre-set speed.

Similar to Example 1, there can be similar variations to Example 2 according to different embodiments of the polarization light source apparatus. For example, the first opening 206 and the second opening 209 in the housing 208 can be respectively configured as the light source apparatus outlet and the light source apparatus inlet, respectively; and correspondingly, the dichroic mirror 207 is configured to transmit the incident excitation light incoming from the second opening 209 therethrough and to reflect an excited light thereon to allow it to emerge out through the first opening 106. In addition, the dichroic mirror 207 and the corresponding first opening 206 can be alternatively arranged between the collimating lens set 203 and the quarter-wave plate 204, or can be alternatively arranged between the quarter-wave plate 204 and the reflective polarizing beam splitter 205. Regardless of the varying embodiments as described above, the incident excitation light can be configured to be a collimated and linearly polarized light (with a polarization direction thereof being substantially parallel with the transmission axis of the reflective polarizing beam splitter 205) that can optionally be provided by a laser diode collimated light source, or can optionally be an output light from other optical devices

Compared with the first embodiment of the polarization light source apparatus 001 shown above in Example 1, this second embodiment of the polarization light source apparatus 002 is capable of emitting polarized lights of different wavelengths in a time sequence (i.e. chronological order) , and the heat dissipation performance is also improved.

Example 3:

In this example, the schematic diagram of a third embodiment of the polarization light source apparatus is illustrated in FIG. 4.

As shown in the figure, the polarization light source apparatus according to this third embodiment 003 substantially comprises a transparent wavelength conversion plate 301, a collimating lens set 303, a quarter-wave plate 304, and a reflective polarizing beam splitter 305, which are arranged in a housing 308. The housing 308 is provided with a first opening 306 and a second opening 309, which serves as the inlet for an incident excitation light 312 and the outlet for an output/emergent light 314, respectively, of the light source apparatus 003. More specifically, the transparent wavelength conversion plate 301, the collimating lens set 303, the quarter-wave plate 304 and the reflective polarizing beam splitter 305 are sequentially ordered in a direction from the first opening 306 to the second opening 309 of the housing 308 (as illustrated by the Y-Axis that is substantially parallel with a direction of the optical path of the lights) . An angle between the slow axis of the quarter-wave plate 304 and the transmission axis of the reflective polarizing beam splitter 305 is arranged to be approximately 45°.

Compared with the first embodiment of the polarization light source apparatus 001 as described above in Example 1, in this third embodiment of the polarization light source apparatus 003, both the top surface and the bottom surface of the transparent wavelength conversion plate 301 are light-transmitting surfaces, and thus no reflective film layer is arranged in the third embodiment of the polarization light source apparatus 003.

As shown in FIG. 4, this third embodiment of the polarization light source apparatus 003 further comprises a transparent substrate 311 below the transparent wavelength conversion plate 301 (i.e. over a surface of the transparent wavelength conversion plate 301 that faces the first opening 306) . The transparent substrate 311 comprises a transparent material, such as optical glass, quartz glass, and other materials, that allows the excitation lights incoming from the first opening 306 (i.e. the light source apparatus inlet) to pass therethrough and shed onto the transparent wavelength conversion plate 301.

In addition, a dichroic film layer 311a is arranged between the transparent wavelength conversion plate 301 and the transparent substrate 311, which can be coated on a bottom surface of the transparent wavelength conversion plate 301 or an upper surface of the transparent substrate 311. The dichroic film layer 311a is configured to be able to transmit the incident excitation light 312 therethrough and to reflect the excited light 313 thereon. It is of note that there is no dichroic mirror in this third embodiment of the polarization light source apparatus 003.

The working mechanism of this third embodiment of the polarization light source apparatus 003 is as follows:

The incident excitation light 312 enters into the interior of the light source apparatus 003 from the light source apparatus inlet (i.e. the first opening 306) . After passing through the transparent substrate 311 and the dichroic film layer 311a, the excitation light 312 sheds onto the transparent wavelength conversion plate 301, and the excitation wavelength conversion material contained in the transparent wavelength conversion plate 301 then emits an excited light 313.

The excited light 313 is a non-polarized light. Part of the excited light 313 may travel upward (i.e. in a direction towards the light source apparatus outlet or the second opening 309) to reach the collimating lens set 303, and part of the excited light 313 may travel downward (i.e. in a direction towards the light source apparatus inlet or the first opening 306) to reach the dichroic film layer 311a, where it is reflected upward again (i.e. in a direction towards the second opening 309) to further reach the collimating lens set 303.

After being collimated by the collimating lens set 303, the excited light 313 passes through the quarter-wave plate 304, and the non-polarized light remains non-polarized after passing through the quarter-wave plate 304. A first portion of the non-polarized light whose polarization direction is substantially parallel with the transmission axis of the reflective polarizing beam splitter 305 is able to pass through the reflective polarizing beam splitter 305 and is then emitted from the light source apparatus outlet 309 to become a first output light beam. A second portion of the non-polarized light whose polarization direction is perpendicular to the transmission axis of the reflective polarization beam splitter 305 is reflected back to the quarter-wave plate 304, and successively passes through the collimating lens set 303 and the transparent wavelength conversion plate 301, and is then reflected by the dichroic film layer 311a. The reflected beam then returns in the original optical path, and after passing through the quarter-wave plate 304, the polarization direction of this reflected beam rotates by 90°. At this time, because this reflected beam has a polarization direction that is substantially parallel with the transmission axis of the reflective polarizing beam splitter 305, it will pass through the reflective polarizing beam splitter 305, and then after passing through the reflective polarizing beam splitter 305, it will be emitted out from the light source outlet 309 to become a second output light beam, which then combines with the first output light beam to thereby become the light source output light beam 314.

Compared with the first embodiment of the polarization light source apparatus 001, this third embodiment of the polarization light source apparatus 003 has a reduced volume, and the excitation light 312 can be a non-polarized light, such as that emitted by an LED light source. It is noted that for Example 3, the excitation light 312 can optionally be a polarized light or a combination of a polarized light and a non-polarized light according to some other embodiments.

Example 4:

Example 4 represents a fourth embodiment of the polarization light source apparatus. As illustrated by the schematic diagram shown in FIG. 5, this fourth embodiment of the polarization light source apparatus 004 is substantially a variant of the third embodiment of the polarization light source apparatus (i.e. Example 3) as described above.

In a configuration similar to the third embodiment of the polarization light source apparatus 003 shown in FIG. 4, this fourth embodiment of the polarization light source apparatus 004 substantially also comprises a transparent substrate a transparent wavelength conversion plate 401, a collimating lens set 403, a quarter-wave plate 404, a reflective polarizing beam splitter 405, which are sequential arranged in a direction from the first opening 406 to the second opening 409 of the housing 408, as illustrated by the Y-Axis that is substantially parallel with the optical path of the lights incoming from the first opening 406 (i.e. the light source inlet for the incident excitation light 412) and emerging from the second opening 409 (i.e. the light source outlet for the output/emerging light 414) . An angle between the slow axis of the quarter-wave plate 404 and the transmission axis of the reflective polarizing beam splitter 405 is arranged to be approximately 45°. The configuration of each of the above optical components, and the working mechanism of the light source apparatus as well, is similar to, and can thus be referenced to, Example 3 as described above, and the description thereof is therefore skipped herein.

Similar to the third embodiment of the polarization light source apparatus 003, both surfaces (i.e. the top surface and the bottom surface) of the transparent wavelength conversion plate 401 are light-transmitting surfaces. The main difference between the third embodiment 003 and the fourth embodiment 004 of the polarization light source apparatus is that the transparent wavelength conversion plate 401 in this fourth embodiment 004 has an annular shape (or a ring shape) and can comprise more than one transparent wavelength conversion material, each arranged within a sub-region of the ring. The configuration of the ring-shaped transparent wavelength conversion plate 401 in this fourth embodiment 004 is similar to the ring-shaped transparent wavelength conversion plate 201 in the second embodiment of the polarization light source apparatus 002 illustrated in FIG. 2B.

As shown in FIG. 5, the ring-shaped transparent wavelength conversion plate 401 is fixedly attached over a transparent substrate 411, which is mounted on a rotating shaft 410. Similar to the third embodiment of the polarization light source apparatus 003, a dichroic film layer 411a is similarly arranged between the transparent wavelength conversion plate 401 and the transparent substrate 411 that can transmit the excitation light 412 but reflect the excited light. The rotating shaft 410 is operably connected with a driving motor (not shown) that is fixedly attached onto the light source housing 408, and is configured to rotate around a rotating axis that is substantially parallel with the direction of the emergent lights emitting out through the light source apparatus outlet (i.e. the first opening) 409, as illustrated by the Y-Axis. When the light source apparatus works, the rotating shaft 410 drives the transparent substrate 411 and the transparent wavelength conversion plate 401 to rotate at a pre-set speed.

Compared with the second embodiment of the polarization light source apparatus 002, this third embodiment of the polarization light source apparatus 004 has a reduced volume, and the excitation light 412 can be a non-polarized light, such as the lights emitted by an LED light source. It is also noted that in Example 4, the excitation light 312 can optionally be a polarized light or a combination of a polarized light and a non-polarized light according to some other embodiments.

Claims

A polarization light source apparatus, comprising a transparent wavelength conversion plate, a collimating lens set, a quarter-wave plate and a reflective polarizing beam splitter, sequentially arranged along an optical path, wherein:

the transparent wavelength conversion plate is arranged approximately at a focal plane of the collimating lens set, and is configured, upon receiving an excitation light, to emit an excited light;

the collimating lens set is configured to collimate the excited light to thereby generate a collimated excited light; and

the quarter-wave plate is configured such that a slow axis thereof has an angle of approximately 45° with a transmission axis of the reflective polarizing beam splitter.
The polarization light source apparatus of claim 1, wherein a direction of the excitation light has an angle less than approximately 35° with the optical path.
The polarization light source apparatus of claim 2, wherein the direction of the excitation light has an angle approximately 0° with the optical path.
The polarization light source apparatus of any of claims 1-3, wherein:

the excitation light sheds onto the transparent wavelength conversion plate from a side thereof proximal to the collimating lens set; and

the polarization light source apparatus further comprises a reflective film layer over a side of the transparent wavelength conversion plate distal to the collimating lens set, with a reflective surface thereof facing the transparent wavelength conversion plate, wherein the reflective film layer is configured to reflect at least a portion of the excited light from the transparent wavelength conversion plate back towards the collimating lens set. .
The polarization light source apparatus of claim 4, wherein:

the excitation light derives from a first incident light transmitting from over a side of the collimating lens set distal to the transparent wavelength conversion plate through the collimating lens set towards the transparent wavelength conversion plate; and

the polarization light source apparatus further comprises a dichroic mirror arranged over a side of collimating lens set distal to the transparent wavelength conversion plate, wherein the dichroic mirror is configured:

to allow a first input light entering into the polarization light source apparatus to reflect thereon to thereby provide the first incident light; or

to allow a second input light entering into the polarization light source apparatus to transmit therethrough to thereby provide the first incident light.
The polarization light source apparatus of claim 5, wherein the dichroic mirror is arranged:

between the collimating lens set and the quarter-wave plate;

between the quarter-wave plate and the reflective polarizing beam splitter; or

over a side of the reflective polarizing beam splitter distal to the quarter-wave plate.
The polarization light source apparatus of claim 5 or claim 6, wherein the dichroic mirror is arranged to have an angle of approximately 30-60° with the optical path.
The polarization light source apparatus of claim 7, wherein the dichroic mirror is arranged to have an angle of approximately 45° with the optical path.
The polarization light source apparatus of any one of claims 5-8, wherein the dichroic mirror is arranged over a side of the reflective polarizing beam splitter distal to the quarter-wave plate and is configured to allow the first input light to reflect thereon to thereby provide the first incident light, wherein the dichroic mirror is further configured to allow a derivative light of the excited light to transmit therethrough to become a first output light emitting out of the polarization light source apparatus.
The polarization light source apparatus of any one of claims 5-8, wherein the dichroic mirror is arranged over a side of the reflective polarizing beam splitter distal to the quarter-wave plate and is configured to allow the second input light to transmit therethrough to thereby provide the first incident light, wherein the dichroic mirror is further configured to allow a derivative light of the excited light to reflect thereon to thereby become a second output light emitting out of the polarization light source apparatus.
The polarization light source apparatus of any of claims 5-10, further comprising a first housing, wherein:

the transparent wavelength conversion plate, the collimating lens set, the quarter-wave plate, the reflective polarizing beam splitter, and the dichroic mirror are arranged within the first housing; and

the first housing is provided with:

an inlet, allowing an input light to enter the polarization light source apparatus therethrough; and

an outlet, allowing an output light to emit out of the polarization light source apparatus therethrough.
The polarization light source apparatus of claim 11, wherein the first housing is provided with a reflective inner side surface.
The polarization light source apparatus of any one of claims 5-12, further comprising a heat dissipating substrate over a side of the reflective film layer distal to the transparent wavelength conversion plate, wherein the heat dissipating substrate is attached onto the transparent wavelength conversion plate and configured to dissipate heat released from the transparent wavelength conversion plate when the polarization light source apparatus is in operation.
The polarization light source apparatus of claim 13, wherein the reflective film layer is integrated with the heat dissipating substrate, with a side surface of the heat dissipating substrate facing the transparent wavelength conversion plate is configured to be reflective.
The polarization light source apparatus of any one of claims 5-14, wherein the first incident light comprises a linearly polarized light with a polarization direction thereof substantially parallel with the transmission axis of the reflective polarizing beam splitter.
The polarization light source apparatus of claim 15, wherein the linearly polarized light is substantially collimated.
The polarization light source apparatus of claim 15 or claim 16, wherein the first incident light derives from an input light provided by a laser diode light source.
The polarization light source apparatus of any of claims 1-3, wherein the excitation light sheds onto the transparent wavelength conversion plate from a side thereof distal to the collimating lens set.
The polarization light source apparatus of claim 18, wherein:

the excitation light derives from a second incident light transmitting from over a side of the transparent wavelength conversion plate distal to the collimating lens set towards the reflective polarizing beam splitter; and

the polarization light source apparatus further comprises a dichroic film layer arranged over a side of the transparent wavelength conversion plate distal to the collimating lens set, wherein the dichroic film layer is configured to allow the second incident light to transmit therethrough to thereby provide the excitation light, and to reflect at least a portion of the excited light from the transparent wavelength conversion plate back towards the reflective polarizing beam splitter along the optical path.
The polarization light source apparatus of claim 19, further comprising a transparent substrate over a side of the dichroic film layer distal to the transparent wavelength conversion plate, configured to allow the second incident light to transmit therethrough.
The polarization light source apparatus of any one of claims 19-20, further comprising a second housing, wherein:

the transparent wavelength conversion plate, the collimating lens set, the quarter-wave plate, the reflective polarizing beam splitter are arranged within the second housing; and

the second housing is provided with an inlet, allowing the second incident light to enter the polarization light source apparatus via the inlet.
The polarization light source apparatus of claim 21, wherein the second housing is provided with a reflective inner side surface.
The polarization light source apparatus of any one of claims 19-22, wherein the second incident light comprises a non-polarized light or a polarized light.
The polarization light source apparatus of claim 23, wherein the second incident light comprises a non-polarized light provided by a light-emitting diode (LED) light source.
The polarization light source apparatus of any one of claims 1-24, wherein the transparent wavelength conversion plate is configured to be adjustably move on a plane that is perpendicular to the optical path.
The polarization light source apparatus of claim 25, wherein the transparent wavelength conversion plate comprises at least two portions, each comprising a different material selected from a reflective material, a transparent material or a transparent wavelength conversion material, wherein the transparent wavelength conversion plate is configured to adjustably move such that the at least two portions of the transparent wavelength conversion plate are alternately arranged in the optical path so that the polarization light source apparatus alternately generates a different output light.
The polarization light source apparatus of claim 26, wherein the transparent wavelength conversion plate consists of three portions, configured such that the polarization light source apparatus alternately generates three different output lights with three different primary colors.
The polarization light source apparatus of claim 27, wherein the three portions respectively comprise three different transparent wavelength conversion materials configured, upon receiving the excitation light, to respectively stimulate three lights with three different primary colors.
The polarization light source apparatus of claim 27, wherein:

two of the three portions respectively comprise two different transparent wavelength conversion materials configured, upon receiving the excitation light, to respectively stimulate generation of two excited lights with two different colors; and

the last one of the three portion comprises one of a transparent material that allows the excitation light to transmit therethrough or a reflective material that allows the excitation light to reflect back therefrom.
The polarization light source apparatus of claim 29, wherein the excitation light is a blue light, and the two excited lights consists of a green light and a red light.
The polarization light source apparatus of claim 30, wherein:

the excitation light is a blue light with a wavelength of 455 nm; and

the two different transparent wavelength conversion materials respectively comprises:

a first green light-stimulating composition selected from LuAG: Ce ³⁺ or MgAlON∶ Mn; and

a second red light-stimulating composition selected from YAG: Mn/Mg, CaAlSiN ₃: Eu ²⁺, Sr ₂Si ₅N ₈: Eu ²⁺, or CaAlSiN ₃: Eu ²⁺.
The polarization light source apparatus of claim 29, wherein the excitation light is a blue light, and the two excited lights consists of a yellow light and a red light, wherein the polarization light source apparatus further comprises a color filer configured to generate a green light from the yellow light.
The polarization light source apparatus of claim 32, wherein:

the excitation light is a blue light with a wavelength of 455 nm; and

the two different transparent wavelength conversion materials respectively comprises:

a first yellow light-stimulating composition of YAG: Ce ³⁺ (Y ₃Al ₅O ₁₂: Ce ³⁺) ; and

a second red light-stimulating composition selected from YAG: Mn/Mg, CaAlSiN ₃: Eu ²⁺, Sr ₂Si ₅N ₈: Eu ²⁺, or CaAlSiN ₃: Eu ²⁺.
The polarization light source apparatus of any one of claims 25-33, wherein the at least two portions of the transparent wavelength conversion plate are arranged at different fan-shaped regions of a circle or at different sectors of a ring, and the transparent wavelength conversion plate is configured to adjustably rotate around a shaft whose rotating axis is substantially at a center of the circle or of the ring.
The polarization light source apparatus of claim 34, wherein the transparent wavelength conversion plate is configured to rotate at a speed of at least 2400 rpm.
The polarization light source apparatus of any one of claims 1-35, wherein the collimating lens set comprises one single convex lens (i.e. biconvex lens) , two plano-convex lenses opposing to each other, or a plurality of convex lenses arranged in an array on a plane that is perpendicular to the optical path.
The polarization light source apparatus of any one of claims 1-36, wherein the collimated excited light emergent from the collimating lens set towards the reflective polarizing beam splitter has a divergence angle of less than approximately 20° relative to the optical path.