WO2015000644A1

WO2015000644A1 - Projector light source comprising light conversion wheel and x-cube

Info

Publication number: WO2015000644A1
Application number: PCT/EP2014/061040
Authority: WO
Inventors: Yi Ding
Original assignee: Osram GmbH
Current assignee: Osram GmbH
Priority date: 2013-07-05
Filing date: 2014-05-28
Publication date: 2015-01-08
Anticipated expiration: 2016-01-05
Also published as: CN104280890A

Abstract

The present invention relates to a prism device 100 for a projector, the prism device comprising a light source and a prism box 3, the prism box comprising first, second, third and fourth surfaces, S1-S4 and an original light L from the light source entering the prism box through the first surface, wherein the prism device further comprises an optical path adjusting means 10 and at least one light conversion means (phosphor wheel) 5 provided downstream from at least one of the first, second, third and fourth surfaces, the optical path adjusting means is configured to guide a first part of the original light through at least one of the second, third and fourth surfaces to the light conversion means, and enable a second part of the original light to emerge through at least one further surface of the second, third and fourth surfaces as an emergent surface, and is configured to guide a converted light Lll from the light conversion means to emerge in a direction parallel to an emergent direction passing through the emergent surface, and guide at least a part of unconverted original light from the light conversion means to emerge in a direction parallel to an emergent direction passing through the emergent surface.

Description

PROJECTOR LIGHT SOURCE COMPRISING LIGHT CONVERSION WHEEL AND X-CUBE Technical Field

The present invention relates to a prism device for light source .

Background Art

In the techniques used in the existing projectors, for in- stance, in the DLP, LCD or LCos type projector, the technique of enabling light with different wavelengths from a light source to emerge through an emergent aperture is used. Howev^¬ er, in this process, for instance, in the technique used in the DLP type projector, in order to enable the light having different wavelengths to emerge through the emergent aper^¬ ture, the light is ejected to the emergent aperture in tem^¬ poral order, instead of passing through the emergent aperture at the same time. In this situation, it will result in that we could not take full advantage of the triplet LCD or LCoS projector. Besides, since mechanism or means capable of ef^¬ fectively recovering the unconverted light is absent, during the emerging process, the unconverted light is wasted as it is not sufficiently used because it fails to emerge from the emergent aperture, and this also will significantly reduce the optical efficiency of the light source of the projector.

Summary of the Invention

In order to solve the above technical problem, the present invention provides a prism device for a light source, which can form a compact optical system using an X-cube and realize light processing of the light source. Besides, upon pro^¬ cessing of the prism device according to the present invention, the power ratio of formed light having different wave^¬ lengths can be properly controlled, and the converted light and the unconverted light can be both used so that the usage efficiency of light of a light source system is improved and elevated. Moreover, light from the light source having dif^¬ ferent wavelengths can be ejected at the same time to an emergent aperture so as to successfully enter next possible optical system.

The first object of the present invention is accomplished via a prism device for a light source. The prism device comprises a light source and a prism box located downstream from the light source, the prism box comprises first, second, third and fourth surfaces, and an original light from the light source enters the prism box through the first surface, char^¬ acterized in that the prism device further comprises an opti^¬ cal path adjusting means and at least one light conversion means provided downstream from at least one of the first, se^¬ cond, third and fourth surfaces, the optical path adjusting means is configured to guide a first part of the original light through at least one of the second, third and fourth surfaces to the light conversion means, and enable a second part of the original light to emerge through at least one further surface of the second, third and fourth surfaces as an emergent surface, and is configured to guide a converted light from the light conversion means to emerge in a direc^¬ tion parallel to an emergent direction passing through the emergent surface, and guide at least a part of unconverted original light from the light conversion means to emerge in a direction parallel to an emergent direction passing through the emergent surface. According to this configuration, the possibility of recovering and re-using part of the unconvert- ed original light using this prism device is realized, based on the use of the converted light.

The term light source comprises all kinds of sources emitting radiation, which can be used to excite luminescent and/or phosphorescent materials ("excitation radiation") , thereby emitting converted radiation ("conversion radiation") . Preferably, the excitation radiation comprises polarized light within a certain wavelength range, e.g. from 405 nm to 470 nm, but may also comprise other wavelengths and/or a combina^¬ tion of various wavelengths (including infrared and/or ultra^¬ violet radiation) . Preferably, one or more polarized light sources with small beam divergences are used as excitation sources, particularly laser diodes or superluminescent di^¬ odes .

According to a preferred solution of the present invention, the optical path adjusting means comprises a fifth surface having a first coating and a sixth surface having a second coating which are provided inside the prism box, and the fifth surface and the sixth surface are formed as internal surfaces of the prism box. The original light can be pro^¬ cessed by using the two surfaces having coatings of different attributes, so as to realize the possibility of, for in^¬ stance, splitting the light and changing the optical path.

Preferably, the optical path adjusting means further compris^¬ es a light recovery means in connection with the prism box, and the light recovery means is configured to at least guide a part of the unconverted original light to emerge in a di^¬ rection parallel to the emergent direction passing through the emergent surface. Thus, it can be realized that the un^¬ converted original light is guided to a direction consistent with that of the original emergent surface to emerge, so as to realize the possibility of re-using the unconverted origi^¬ nal light.

Preferably, the light recovery means is provided downstream from the fifth surface and the sixth surface in optical path. Consequently, the converted light converted by the light con- version means and the unconverted original light both can be re-used and processed in the light recovery means provided downstream so as to realize the possibility of improving the efficiency of the light source.

Preferably, the light recovery means guides a part of the un- converted original light, after conversion of polarization state, to emerge in a direction parallel to the emergent di^¬ rection passing through the emergent surface. Therefore, the possibility of changing the polarization of the unconverted original light can be realized so as to meet the requirement of the emergent light in the aspect of the polarization state .

Preferably, one light conversion means is provided outside the second surface. Such configuration is beneficial for forming a compact and concise optical path so as to obtain eventually a compact prism device and the possibility of re^¬ using the unconverted original light downstream the optical path .

Preferably, a normal of the fifth surface and a normal of the sixth surface are configured perpendicular to each other. Thus, according to demand of practical application circumstances, the two surfaces can be arranged inside the prism box perpendicularly in multiple different ways so as to real^¬ ize, for instance, that the light of the original light is incident upon one of the surfaces at 45° and the converted light also is incident upon the other surface at 45° to fi^¬ nally achieve the object of guiding the light towards a par^¬ ticular direction and splitting the light.

Preferably, viewed from a cross section of the prism box, the fifth surface and the sixth surface extend from one corner to an opposite corner of the prism box, respectively, so as to be configured perpendicular to each other. Such configuration can satisfy the requirement of the above incident angle to achieve the object of guiding and splitting the light. Preferably, the original light comprises a first original light having a first excited state and a second original light having a second excited state, the unconverted light comprises a first converted light having the first excited state and a second converted light having the second excited state, wherein the light recovery means is at least config^¬ ured to convert the first original light to the second origi^¬ nal light or convert the second original light to the first original light; or, is configured to convert the first con- verted light to the second converted light or convert the se^¬ cond converted light to the first converted light. According to such configuration, the possibility of keeping consistent the excited state of the emergent light obtained by the light recovery device with the excited state of the emergent light obtained directly through the prism box can be realized, moreover, the emergent light in the desired excited state can be obtained according to different practical application cir^¬ cumstances .

Preferably, the first coating is configured to allow trans- mission of one of the first original light and the second original light and reflection of the other one of the first original light and the second original light; and the second coating is configured to allow transmission of the other one of the first original light and the second original light and reflection of the one of the first original light and the se^¬ cond original light. Consequently, the possibility of split^¬ ting and guiding the original light having different excited states can be realized.

Advantageously, the second coating is configured to reflect the first converted light and the second converted light for exiting. Thus, it can be realized that the desired converted light is directly guided to the emergent surface.

Preferably, the light recovery means is configured to be formed downstream from the fourth surface, wherein the fourth surface is opposite to the second surface. According to such configuration of the optical path, the converted light which originally may directly emerge can be re-used after guided to the light recovery means.

Preferably, the light recovery means is configured as a wave plate. According to the specific requirement, the wave plate can change the polarization state of the incident light so as to realize the possibility of changing the excited state of the incident light after processing the incident light. Preferably, the first original light and the second original light, and the polarization state of the first converted light and the second converted light is perpendicular to each other, respectively, and the wave plate is configured as a quarter wave plate. The half wave plate can change the polar- ization state of the light passing therethrough, so as to realize the possibility of changing the excited states of the original light and the converted light between the first ex^¬ cited state and the second excited state.

Preferably, the first excited state and the second excited state are P-polarization state and S-polarization state, or S-polarization state and P-polarization state, respectively. Therefore, the requirement to the polarization state of the emergent light can be met.

Preferably, emergent light passing through the emergent sur- face comprises mixed light in different polarization states. Therefore, the requirement to the polarization state of the emergent light can be met, and the possibility of re-using the converted light in at least one polarization state is re^¬ alized. Preferably, the third surface opposite to the first surface acts as the emergent surface. Thus, while the simple and rea^¬ sonable design of the optical path is satisfied, the third surface can be configured as the emergent aperture of the light of the light source after processing. Preferably, the light recovery means comprises a first subu- nit and a second subunit, and the first subunit is configured to at least guide a part of the unconverted original light, after change of polarization state, to emerge through the se- cond subunit. According to such configuration, while the converted light is changed of the polarization state and guided to the emergent surface, the same configuration also can be used for emergence of the unconverted original light after suitable change of the polarization state.

Preferably, the second coating is configured to allow reflec^¬ tion of one of the first converted light and the second con^¬ verted light and transmission of the other one of the first converted light and the second converted light to the light recovery means. In this way, the possibility of maintaining consistent the polarization state of one of the two converted light, after processing by the light recovery means with that of the other converted light can be realized.

Advantageously, emergent light emerging through the emergent surface and emergent light emerging through the second subu^¬ nit have the same polarization state. Thus, it can be ensured that the emergent light having the same polarization state is provided .

Preferably, the first subunit comprises a third coating and a third wave plate provided downstream from the third coating, and the second subunit is a fourth wave plate provided down^¬ stream from the third wave plate. By using the third coating, it can be realized that, while the converted light is re^¬ flected, for instance, the unconverted original light is transmitted, and then after the polarization state of the un^¬ converted original light is changed via the configuration of the wave plate, and upon the processing by the fourth wave plate, the polarization state of the unconverted original light can be consistent with that of the converted light re- fleeted by the third coating.

Preferably, the third coating is configured to reflect the first converted light or the second converted light for exit^¬ ing, and to transmit unconverted first original light or se^¬ cond original light to the third wave plate, the third wave plate converts the first original light or the second origi^¬ nal light to the second original light or the first original light and guides it to the fourth wave plate, and the fourth wave plate converts the second original light or the first original light to the first original light or the second original light. Therefore, the polarization state of the con^¬ verted light emerging through the fourth wave plate can be kept consistent with that of the unconverted original light emerging through the fourth wave plate. Preferably, the fourth wave plate is configured to extend from an end of the fourth surface along one end of the third surface to a direction away from the light conversion means, and the third wave plate is configured to join the other end of the fourth surface and an opening end of the fourth wave plate. Thus, the emergent direction of the converted light emerging through the light recovery means or the unconverted original light can be kept consistent with that of the emer^¬ gent light emerging directly through, for instance, the third surface as the emergent surface, of the prism box. Preferably, the fourth wave plate and the third wave plate are configured to form an angle of 45° with each other. Therefore, it can be satisfied that the unconverted original light entering the light recovery means and the converted light are guided to the desired emergent direction. Preferably, the fourth wave plate is configured as a half wave plate. After the polarization state of the unconverted original light entering the light recovery means and the con^¬ verted light can be changed by the half wave plate, the po^¬ larization state thereof is then changed. Preferably, the first subunit comprises a seventh wave plate and a fifth wave plate both provided downstream from the fourth surface and a fourth coating provided downstream from the fifth wave plate, and the second subunit is a sixth wave plate. Therefore, the light entering the light recovery means can be subject o corresponding change of the polarization state of the light successively by the fifth wave plate and the sixth wave plate, so that the possibility of keeping con^¬ sistent the polarization state of the emergent light with the polarization state of the emergent light emerging through the prism box can be realized.

Preferably, the seventh wave plate performs primary conver^¬ sion for one of the first converted light and the second con^¬ verted light, and reflects it through the third coating to the sixth wave plate for secondary conversion, so as to obtain the other converted light of the emerging second con^¬ verted light and first converted light. According to such configuration of the optical path, the polarization state of the first converted light or of the second converted light can be changed correspondingly successively by the fifth wave plate and the sixth wave plate so as to achieve the possibil^¬ ity of finally changing the polarization state of the light.

Preferably, the first original light and the second original light, and the polarization state of the first converted light and the second converted light is perpendicular to each other, and the fifth wave plate, the sixth wave plate and the seventh wave plate are configured as a quarter wave plate. The polarization state of the first original light and the second original light, and the first converted light and the second converted light is changed successively by the fifth wave plate and the sixth wave plate so as to finally achieve the same effect as, for instance, only using one half wave plate to change the polarization state of the light.

Preferably, the seventh wave plate is configured to be paral- lei with the fourth surface, the sixth wave plate is config^¬ ured to extend from an end of the fourth surface along one end of the third surface to a direction away from the light conversion means, the fifth wave plate is configured to join the other end of the fourth surface and an opening end of the sixth wave plate, and the fourth coating is provided on the fifth waveplate. Thus, the emergent direction of the convert^¬ ed light or the unconverted original light emerging through the light recovery means can be kept consistent with the emergent direction of the emergent light directly emerging through the prism box.

According to a preferred solution of the present invention, the light conversion means comprises one phosphor means hav^¬ ing at least one types of phosphors. According to such con^¬ figuration, the possibility of having the converted light simultaneously with different wavelengths can be realized.

The term phosphor comprises all kinds and/or mixtures of ma^¬ terials that are capable of emitting converted radiation (e.g. in the visible wavelengths range: "conversion light") upon irradiating with excitation radiation (e.g. blue light emitted by a laser diode) . The excitation radiation may be converted by down-conversion or by up-conversion.

Preferably, the number of the light conversion means is two, and respective light conversion means is configured to com^¬ prise phosphor means having a single phosphor. Two light con- version means can be used simultaneously to achieve the same or similar effect as that of the phosphor means having at least two types of phosphors.

Advantageously, the optical path adjusting means is config^¬ ured to divide the first part of the original light into two parts so as to guide it through each of two of the second, third and fourth surfaces to the phosphor means. Thus, after different parts of the original light can be guided to dif^¬ ferent phosphor means, it is realized that the wavelengths of different parts of the original light are changed correspond- ingly to finally obtain the converted light with different wavelengths .

Preferably, the optical path adjusting means comprises a fifth surface having a first coating and a sixth surface hav- ing a second coating which are provided inside the prism box, the first coating is configured to reflect one part of the first part of the original light to one phosphor means, the first coating and the second coating are configured to trans- mit the other part of the first part of the original light to the other phosphor means; and the second coating is configured to reflect the second part of the original light to the emergent surface. According to the configuration of the two phosphor means, for instance, on the second surface and the third surface, it can be realized that the light after pro^¬ cessing by the prism box and the phosphor means, emerges, e.g. from the fourth surface of the prism box.

Preferably, the first coating and the second coating are con^¬ figured to allow transmission of converted light from the one phosphor means to the emergent surface, and allow transmis^¬ sion of converted light from the other phosphor means through the second coating to enter the emergent surface after re^¬ flected by the first coating. Therefore, light from the phos^¬ phor means located in different positions can emerge uniform- ly from the same emergent surface, for instance, the fourth surface .

Preferably, the optical path adjusting means comprises a fifth surface having a first coating and a sixth surface having a second coating which are provided inside the prism box, the first coating is configured to reflect one part of the first part of the original light to one phosphor means, the first coating and the second coating are configured to trans^¬ mit the other part of the original light to the emergent sur^¬ face; and the second coating is configured to reflect a se- cond part of the original light to the other phosphor means. According to the configuration of the two phosphor means, for instance, on the second surface and the fourth surface, it can be realized that all light after processing by the prism box and the phosphor means emerges from, e.g. the third sur- face of the prism box. Preferably, the first coating and the second coating are con^¬ figured to allow transmission of converted light from one phosphor means and converted light from the other phosphor means through the second coating to enter the emergent sur- face after reflected by the first coating. Therefore, light from the phosphor means provided in different positions can uniformly emerge from the same emergent surface, e.g. the third surface.

According to a preferred solution of the present invention, the first, second, third and fourth surfaces of the prism de^¬ vice have an antireflective coating. As a result, decreasing of the light energy of light passing through the four surfac^¬ es can be avoided as much as possible so as to ensure the op^¬ tical efficiency of the whole prism device. Brief Description of the Drawings

The accompanying drawings constitute a part of the present Description and are used to provide further understanding of the present invention. Such accompanying drawings illustrate the embodiments of the present invention and are used to de- scribe the principles of the present invention together with the Description. In the accompanying drawings the same compo^¬ nents are represented by the same reference numbers. As shown in the drawings :

Fig. la - Fig. lc are schematic diagrams of a prism device according to a first embodiment of the present invention;

Fig. Id is a schematic diagram of the prism device according to a second embodiment of the present invention;

Fig. 2a - Fig. 2b are schematic diagrams of the prism device according to a third embodiment of the present invention; Fig. 3 is a schematic diagram of the prism device according to a fourth embodiment of the present invention;

Fig. 4 is a schematic diagram of a phosphor wheel of the prism device according to the embodiments of the present in^¬ vention ; Fig. 5 is a schematic diagram of configuration of a fifth surface and a sixth surface of the prism device according to the present invention; and

Fig. 6 is a schematic diagram of the prism device according to a fifth embodiment of the present invention. Detailed Description of the Embodiments

As shown in Fig. la - Fig. lc, they are schematic diagrams of a prism device 100 according to a first embodiment of the present invention, wherein the prism device 100 comprises a prism box 3, of which four surfaces are coated with antire- flective coatings so as to ensure that light energy of light passing through these surfaces will not be influenced, and a phosphor wheel 52 (to be explained in detailed later on) pro^¬ vided on a second surface S2 of the prism box 3 and at least one lens 51. Besides, the prism device 100 further comprises an optical path adjusting means 10 which includes a quarter wave plate provided downstream from a fourth surface S4, and a fifth surface S5 having a first type of coating and a sixth surface S6 having a second type of coating provided inside the prism box 3. In the above, according to attributes of the coatings, light having different polarization states will be reflected or transmitted by the surfaces having the coatings with corresponding attributes. Specifically, Fig. la to Fig. lc show that the fifth surface S5 is configured in such as manner that a first original light LI which is pump light and has an S-polarization state passes through and a second original light L2 which is pump light in a P-polarization state is reflected, and meanwhile all converted light L' passes through; and the sixth surface S6 is configured in such a manner that all light L which is pump light passes through, and meanwhile all converted light L' is reflected. According to such configuration, the light L which is the pump light from the light source enters from a first surface SI of the prism box 3, the first original light LI and the second orig^¬ inal light L2 having the P-polarization state and the S- polarization state, respectively, directly passes through the sixth surface S6 and reaches the fifth surface S5, due to the second type of coating on the fifth surface S5, the first original light LI having the P-polarization state is reflect^¬ ed and passes through the second surface S2 of the prism box 3 to arrive at a light conversion means 5, and at the same time, the second original light L2 having the S-polarization state directly passes through the fifth surface S5 and emerg- es through the third surface S3 of the prism box 3. In this way, after the light L from the light source has undergone processing of the prism box 3, the second original light L2 having the S-polarization state emerges from the prism device 100, and the first original light LI having the P- polarization state strikes the phosphor wheel 52 after converged by the lens 51. The converted light L' converted by the light conversion means 5 and the unconverted original light L which is not converted are reflected and re-enter the prism box 3, which will be described in detail in Fig. lb - Fig. lc.

In reference to Fig. lb - Fig. lc, the converted light L' from a phosphor means 52 and the unconverted original light L enter the prism box 3 after passing through the lens 51. At this time, according to the configuration of the coatings of the fifth surface S5 and the sixth surface S6 described be^¬ fore, all converted light L' is reflected by the sixth sur^¬ face S6 to the third surface S3 of the prism box 3 to emerge. Moreover, after the unconverted original light L enters the prism box 3 together with the converted light L' , the first original light LI having the P-polarization state, when confronted with the fifth surface S5, is reflected to the first surface SI of the prism box 3, while the second original light L2 having the S-polarization state directly passes through the fifth surface S5 and the sixth surface S6 and reaches the fourth surface S4 of the prism box 3. Since down^¬ stream from the fourth surface S4 is provided, e.g. a quarter wave plate as a light recovery unit 4, when the second origi^¬ nal light L2 having the S-polarization state perpendicularly enters the fourth surface S4 and is reflected towards the prism box 3, the second original light L2 in the S- polarization state is changed into the first original light LI in the P-polarization state, and then the second original light L2 as the first original light LI undergone the change of the polarization state emerges from the fourth surface S4 into the prism box 3. Thereafter, the first original light LI is emitted from the fourth surface S4 to the fifth surface S5, and is rejected on the fifth surface S5 to the third sur^¬ face S3 of the prism box 3 to emerge. Consequently, in the prism device 100 according to the first embodiment, the light emerging from the third surface S3 as an emergent aperture includes the first and second converted light LI', L2' and the first original light LI of the unconverted original light .

In addition, in the prism device 100 according to an embodiment of the present invention not shown, it is different from the first embodiment mentioned above in that the fifth sur- face S5 in the prism box 3 in this embodiment is configured to reflect the second original light L2 having the S- polarization state, while the first original light LI having the P-polarization state can directly pass through the fifth surface S5. That is, according to the above two embodiments, based on the difference of the configuration of the coatings on the fifth surface S5 and the sixth surface S6, the light finally emerg^¬ ing from the third surface S3 as the emergent aperture of the prism box 3 can include the unconverted first original light LI in the P-polarization state or the unconverted second original light L2 in the S-polarization state. Besides, the unconverted original light L emerging through the first sur^¬ face SI and returning back to the direction of the light source can be re-reflected into the prism box 3 to be reused so as to eventually realize the purpose of recovering the un- converted original light and achieving the effect of improv^¬ ing the optical efficiency of the light source.

Further, Fig. Id is a schematic diagram of the prism device 100 according to the second embodiment of the present inven^¬ tion. As shown in Fig. Id, according to this configuration, the difference from the above two embodiments lies in that the phosphor wheel 52 as shown can be provided on, for instance, a further surface different from the second surface S2, e.g. the third surface S3. At this time, the second sur^¬ face S2 of the prism box 3 may be used as an emergent sur- face, the second original light L2 having the S-polarization state of the light L from the light source, for example, when confronted with the fifth surface S5 having a first coating CI, is reflected towards the second surface S2 to emerge, the second original light L2 of the light L having the P- polarization state, after directly passing through the fifth surface S5 having the first coating CI and the sixth surface S6 having a second coating C2, directly arrives at the light conversion means 5 through the third surface S3. The convert^¬ ed light L' processed by the light conversion means 5 and the unconverted original light L will emerge through the second surface S2. It can thus be seen that, by providing the light conversion means 5 outside different surfaces of the prism box 3, one of the other surfaces can be used as the emergent surface . Fig. 2a - Fig. 2b show schematic diagrams of the prism device 100 according to a third embodiment of the present invention. What differs from the above embodiments, such as the first and second embodiments, this prism device 100 is provided with a different light recovery unit 4 which has a first sub- unit 41 configured as, e.g. a quarter wave plate, and a se^¬ cond subunit 42 configured as, e.g. a half wave plate. In ad- dition, Fig. 2a shows a schematic diagram of optical path of the converted light L' of the prism device 100 according to the third embodiment of the present invention, wherein the phosphor wheel 52 and the lens 51 are provided outside the second surface S2 of the prism box 3 as shown in the figure, and the light recovery unit 4 as a part of the optical path adjusting means 10 at this time receives the converted light L' from the phosphor wheel 52 and the unconverted original light L. The converted light L' after converted by the phos- phor wheel 52, after converged by the lens 51, enters the prism box 3 through the second surface S2. According to the configuration of the fifth surface S5 having the first coat^¬ ing and the sixth surface S6 having the second coating, for example, when a part of a second converted light L2' having the S-polarization state is confronted with the sixth surface S6, the second converted light L2' is reflected and guided to emerge towards the third surface S3, and meanwhile, the other part of the second converted light L2', after projecting through the fifth surface S5, is reflected when confronted with the sixth surface S6, and likewise is reflected and guided towards the third surface S3 to emerge. At the same time, a first converted light LI' having the P-polarization state, after passing through the fifth surface S5 and the sixth surface S6, is confronted with a third wave plate P3 having a third coating C3, wherein a fourth wave plate P4 is provided downstream from the third wave plate P3, and the first converted light LI' emerges through the fourth wave plate P4 after reflected by the third wave plate P3, wherein the fourth wave plate P4 is configured to extend along the third surface S3 towards a direction away from the second surface S2, and is configured as a half wave plate. When the first converted light LI' passes through the fourth wave plate P4, the first converted light LI' will be changed into the second converted light L2' having the S polarization state-polarization state due to change of the polarization state. In this way, light emerging from the fourth wave plate P4 will maintain a polarization state consistent with that of the light emerging from the third surface S3, both being the S-polarization state in this embodiment.

It should be indicated that, an angle between the third wave plate P3 and the fourth wave plate P4 can be adjusted, for instance, according to requirement to the optical distribu- tion or optical angle of the emergent light. In the present embodiment, in order to maintain parallel the light emerging from the fourth wave plate P4 with the light emerging from the third surface S3, the angle between the third wave plate P3 and the fourth wave plate P4 can be 45°. Fig. 2b shows a schematic diagram of an optical path of the unconverted original light L of the prism device 100 accord^¬ ing to the third embodiment of the present invention. While having the optical path of the converted light L' as shown in Fig. 2a, after the unconverted original light L enters the prism box 3 from the second surface S2, a part of the uncon^¬ verted first original light LI having the P-polarization state, after confronted with the fifth surface S5, is re^¬ flected to the first surface SI and emerges, after the uncon^¬ verted second original light L2 having the S-polarization state passes through the fourth surface S4, as the first sub- unit 41 such as a quarter wave plate is provided downstream from the third wave plate P3, and the light passing through and reflected by this wave plate will be changed in polariza^¬ tion state , the light emerging from this wave plate there- fore has a changed polarization state. In this embodiment, after the unconverted second original light L2 having the S- polarization state passes through the first subunit 41 and is reflected and re-emerges, the unconverted first original light LI having the P-polarization state is formed, and then, the polarization state of the unconverted first original light LI having the P-polarization state, after passing through the second subunit 42 configured as a half wave plate, is changed again, at which time, the polarization state after changed by the half wave plate is the S- polarization state. Thus, according to this configuration, the unconverted original light L emerging from the fourth wave plate P4 as an emergent surface can keep a polarization state consistent with that of the converted light L' emerging from the third surface S3 and the fourth wave plate P4, both being the S-polarization state in the present embodiment. In addition, in the prism device 100 according to a third embodiment of the present invention not shown, only by changing the attributes of the respective coatings of the fifth sur^¬ face S5 and the sixth surface S6, the converted light L2' having the P-polarization state can directly pass through the fifth surface S5 and the sixth surface S6, and the converted light LI' having the S-polarization state, when confronted with the sixth surface S6, can be directly reflected towards the third surface S3 as the emergent surface, and the uncon^¬ verted original light L2 having the S-polarization state, when confronted with the fifth surface S5, is directly re^¬ flected towards the first surface SI to emerge, the uncon^¬ verted first original LI having the P-polarization state can directly pass through the fifth surface S5 and the sixth sur^¬ face S6, and it can be realized, on the basis of the struc- ture of the prism device 100 as shown in the third embodi^¬ ment, to emerge from the third surface S3 and the fourth wave plate P4 the converted light L' having the P-polarization state and the unconverted original light LI having the P- polarization state. Unnecessary details will not be given herein.

Fig. 3 is a schematic diagram of the prism device 100 accord^¬ ing to a fourth embodiment of the present invention. Similarly, with the aid of the optical path as shown in Fig. la, the light from the light source, upon guidance and processing by the prism box 3, can strike the light conversion means 5. Thus, the converted light L' from the light conversion means 5 and the unconverted original light L pass through the se^¬ cond surface S2 as shown in the figure to enter the prism box 3. According to the configuration of the coatings on the fifth surface S5 and the sixth surface S6, for example, the second converted light L2' having the S-polarization state, when confronted with the sixth surface S6 having the second coating, is directly reflected towards the third surface S3, and emerges through the third surface S3 after passing through the fifth surface S5 having the first coating. Mean- while, the first converted light LI' having the P- polarization state directly passes through the fifth surface S5 and the sixth surface S6, as a quarter wave plate, for in^¬ stance, is provided downstream from the fourth surface S4, the converted light L' simultaneously having the P- polarization state and the S-polarization state will be formed after the first converted light LI' in the P- polarization state passes through the quarter wave plate. Ac^¬ cording to the fifth wave plate P5 provided downstream from the fourth surface S4 and the fourth coating C4 provided on the surface of the fifth wave plate P5, the converted light L' is directly reflected by the fourth coating C4 towards the sixth wave plate P6 provided downstream from the fifth wave plate P5. When the sixth wave plate P6 is configured as, for example, a quarter wave plate, the converted light L' re- fleeted by the third coating C3 is completely converted to the converted light L2' having the S-polarization state.

In the prism device 100 according to the fourth embodiment of the present invention not shown, only by changing the attributes of the respective coatings on the fifth surface S5 and the sixth surface S6, it can be realized, on the basis of the structure of the prism device 100 as shown in the fourth em^¬ bodiment, that the converted light L' having the P- polarization state and the unconverted original light LI hav^¬ ing the P-polarization state emerge from the third surface S3 and the fourth wave plate P4, . Unnecessary details will not be given herein. Besides, an angle between the fifth wave plate and the sixth wave plate can be adjusted, for instance, according to requirement to the optical distribution or opti^¬ cal angle of the emergent light. In the present embodiment, in order to maintain parallel the light emerging from the sixth wave plate with the light emerging from the third sur^¬ face S3, the angle between the fifth wave plate and the sixth wave plate can be 45°.

Fig. 4 is a schematic diagram of the phosphor wheel of the prism device 100 according to the embodiments of the present invention. In the present invention, processing such as con- version and recovery of the light L from the light source is realized by means of such phosphor wheel and the X-cube. Ref^¬ erence can be made to Fig. la for the basic structure of the prism device 100 according to the present invention, wherein the prism device 100 uses the phosphor wheel as shown in Fig. la, while phosphor wheel is configured with a round profile and has, for instance, a hollow circular center, for facilitating installation and connection. Besides, this wheel is also provided with at least one phosphor for converting, e.g. pump light from the light source. According to the embodiment as shown in Fig. la, the wheel has two types of phosphors, and the two types of phosphors are configured on the wheel in a manner of taking circular centers act as concentric cir^¬ cles, which can ensure uniform distribution of the light L from the light source in a circumferential direction of the wheel. Specifically, according to different places of the wheel where the light L strikes, control to the power ratio of the converted light converted by the phosphor and emerging from the wheel having different wavelengths can be realized. For example, when a proportion of the light L distributed on a phosphor 1 is greater than that of the light L distributed on a phosphor 2, the power of converted light converted by the phosphor 1 and having a first wavelength will be greater than the power of the converted light converted by the phos^¬ phor 2 and having a second wavelength, thus realizing regula- tion and control to the power ratio of the converted light having different wavelengths.

It should be noted in all of the above embodiments, for in^¬ stance, in the first to the fourth embodiments, the phosphor means 52 can be implemented by the phosphor wheel as shown in Fig. 4 so as to realize the object of regulating and control^¬ ling the power ratio of the light of the converted light hav- ing different wavelengths.

Fig. 5 is a schematic diagram of configuration of the fifth surface S5 and the sixth surface S6 of the prism device 100 according to the present invention. In reference to Fig. la to Fig. 3, the prism device 100 according to the present in^¬ vention comprises the phosphor means 52 which is configured as, for instance, the phosphor wheel, the prism box 3 config^¬ ured to process the light L from the light source, and a lens 51, wherein the lens 51 is configured to converge the light L passing through the prism box 3 or to diffuse the converted light from the phosphor means 52, and the prism box 3 is con^¬ figured as, for instance, X-cube, which X-cube can serve functions such as splitting or steering light of the light L from the light source. Besides, the prism box 3 of the prism device 100 further comprises the fifth and sixth surfaces S5, S6 provided inside the box, for example, according to the lateral view of the prism box 3 as shown in Fig. la, the two surfaces S5 and S6 not only can be configured to be perpen^¬ dicular to each other, but also can be configured in such a manner that normals of respective surfaces are perpendicular to each other as shown in the schematic diagram of Fig. 5, that is, the fifth surface S5 extends from the left side of the second surface to the right side of the fourth surface, and the sixth surface S6 extends from a diagonal of the first surface to the corresponding diagonal of the third surface, in other words, the fifth surface S5 and the sixth surface S6 are configured in such a manner that the light L can be inci^¬ dent upon the fifth surface S5 at 45°, and the converted light L' converted by the phosphor means 52 is incident upon the sixth surface at 45°.

It should be noted that the above configuration of the fifth surface S5 and the sixth surface S6 can be applied to the prism box 3 as shown in Fig. la to Fig. 3.

Fig. 6 is a schematic diagram of the prism device 100 accord- ing to a fifth embodiment of the present invention. The prism device 100 can be configured with, for instance, two phosphor means 5, and four surfaces of the prism box 3 are all coated with antireflective coatings to ensure that the light energy of light passing through these surfaces will not be influ- enced. At this time, each phosphor means 5 is configured with a single phosphor, as shown in Fig. 6, each of two phosphor means 5 has a different phosphor. According to the fifth embodiment, the two phosphor means 5 are configured outside the second surface S2 and the third surface S3 of the prism box 3, respectively, at which time, the fourth surface S4 of the prism box 3 acts as an emergent surface. According to the fifth embodiment, a first part, for instance, of the pump light L from the light source after reflected by the fifth surface S5 having the first coating, passes through the se- cond surface S2 to reach a first phosphor means 521; a second part of light from the light source, after directly passing through the fifth surface S5 and the sixth surface S6 having the second coating, reaches a second phosphor means 522; and a third part of light from the light source, after reflected by the sixth surface S6, will emerge through the fourth sur^¬ face S4. In this way, all light from the light source can be sufficiently used, and the emergent light can be ensured to collectively emerge, for instance, from the fourth surface S4. Of course, according to the requirement to selection of the emergent surface of the prism box 3, the two phosphor means 5 also can be provided, for instance, outside the second sur^¬ face S2 and the fourth surface S4 of the prism box 3, respec^¬ tively, at which time the third surface S3 of the prism box 3 acts as the emergent surface. In the prism device 100 accord^¬ ing to the fifth embodiment of the present invention not shown, the first part of, for instance, the pump light from the light source, after reflected by the fifth surface S5 having the first coating, passes through the second surface S2 to reach the first phosphor means 521; the second part of light from the light source, after directly passing through the fifth surface S5 and the sixth surface S6 having the se- cond coating, emerges through the third surface S3; the third part of light from the light source, after reflected by the sixth surface S6, will reach the second phosphor means 522 through the fourth surface S4. Thus, all light from the light source can be sufficiently used, and the emergent light can be ensured to collectively emerge from, for instance, the fourth surface S4.

The above is merely preferred embodiments of the present in^¬ vention but not to limit the present invention. For the per- son skilled in the art, the present invention may have vari^¬ ous alterations and changes. Any alterations, equivalent sub^¬ stitutions, improvements, within the spirit and principle of the present invention, should be covered in the protection scope of the present invention.

_ _n

Z 5

List of reference signs

3 prism box

4 light recovery means

5 light conversion means

10 optical path adjusting means

41 first subunit

42 second subunit

52 phosphor means

51 lens

100 prism device

521 first phosphor means

522 second phosphor means

51 first surface

52 second surface

S3 third surface

54 fourth surface

55 fifth surface

56 sixth surface

P3 third wave plate ^ _r

P4 fourth wave plate

P5 fifth wave plate

P6 sixth wave plate

L original light

L10 first part of original light

Lll second part of original light

LI first original light

L2 second original light

L' converted light

LI' first converted light

L2' second converted light

Claims

Patent claims

1 . A prism device (100), comprising a light source and a prism box (3) located downstream from the light source, the prism box (3) comprising first, second, third and fourth surfaces (S1 , S2, S3, S4), and an original light (L) from the light source entering the prism box (3) through the first surface (S1 ), characterized in that the prism device (100) further comprises an optical path adjusting means (10) and at least one light conversion means (5) provided downstream from at least one of the first, second, third and fourth surfaces, the optical path adjusting means (10) is configured to guide a first part (L10) of the original light (L) through at least one (S2; S2, S3; S2, S4) of the second, third and fourth surfaces to the light conversion means (5), and enable a second part (L1 1 ) of the original light (L) to emerge through at least one further surface (S3; S4; S3) of the second, third and fourth surfaces as an emergent surface, and is configured to guide a converted light (Ι_') from the light conversion means (5) to emerge in a direction parallel to an emergent direction passing through the emergent surface, and guide at least a part of unconverted original light (L) from the light conversion means (5) to emerge in a direction parallel to an emergent direction passing through the emergent surface.

2. The prism device (100) according to Claim 1 , characterized in that the opti- cal path adjusting means (10) comprises a fifth surface (S5) having a first coating

(C1 ) and a sixth surface (S6) having a second coating (C2) which are provided inside the prism box (3), and the fifth surface (S5) and the sixth surface (S6) are formed as internal surfaces of the prism box (3).

3. The prism device (100) according to Claim 2, characterized in that the opti- cal path adjusting means (10) further comprises a light recovery means (4) in connection with the prism box (3), and the light recovery means (4) is configured to at least guide a part of the unconverted original light to emerge in a direction parallel to the emergent direction passing through the emergent surface.

4. The prism device (100) according to Claim 3, characterized in that the light recovery means (4) is provided downstream from the fifth surface (S5) and the sixth surface (S6) in optical path.

5. The prism device (100) according to Claim 4, characterized in that the light recovery means (4) guides a part of the unconverted original light (L), after conversion of polarization state, to emerge in a direction parallel to the emergent di- rection passing through the emergent surface.

6. The prism device (100) according to any one of Claims 4-5, characterized in that one of the light conversion means (5) is provided outside the second surface (S2).

7. The prism device (100) according to Claim 6, characterized in that the original light (L) comprises a first original light (L1 ) having a first excited state and a second original light (L2) having a second excited state, the converted light (Ι_') comprises a first converted light (Ι_1 ') having the first excited state and a second converted light (Ι_2') having the second excited state, wherein the light recovery means (4) is at least configured to convert the first original light (L1 ) to the second original light (L2) or convert the second original light (L2) to the first original light (L1 ); or, is configured to convert the first converted light (Ι_1 ') to the second converted light (Ι_2') or convert the second converted light (Ι_2') to the first converted light (Ι_1 ').

8. The prism device (100) according to Claim 7, characterized in that the first coating (C1 ) is configured to allow transmission of one of the first original light (L1 ) and the second original light (L2) and reflection of the other one of the first original light (L1 ) and the second original light (L2); and the second coating (C2) is configured to allow transmission of the first original light (L1 ) and the second original light (L2).

9. The prism device (100) according to any one of Claims 4-5, characterized in that the light recovery means (4) is configured to be formed downstream from the fourth surface (S4), wherein the fourth surface (S4) is opposite to the second surface (S2).

10. The prism device (100) according to any one of Claims 4-5, characterized in that the light recovery means (4) comprises a first subunit (41 ) and a second sub- unit (42), and the first subunit (41 ) is configured to at least guide a part of the unconverted original light (L), after change of polarization state, to emerge through the second subunit (42).

1 1 . The prism device (100) according to Claim 10, characterized in that the second coating (C2) is configured to allow reflection of one of the first converted light (L1 ') and the second converted light (Ι_2') and transmission of the other one of the first converted light (Ι_1 ') and the second converted light (Ι_2') to the light recovery means (4).

12. The prism device (100) according to Claim 1 1 , characterized in that emergent light emerging through the emergent surface and emergent light emerging through the second subunit (42) have the same polarization state.

13. The prism device (100) according to Claim 12, characterized in that the first subunit (41 ) comprises a third coating (C3) and a third wave plate (P3) provided downstream from the third coating (C3), and the second subunit (42) is a fourth wave plate (P4) provided downstream from the third wave plate (P3).

14. The prism device (100) according to Claim 13, characterized in that the third coating (C3) is configured to reflect the first converted light (Ι_1 ') or the second converted light (Ι_2') for exiting, and to transmit unconverted first original light (L1 ) or second original light (L2) to the third wave plate (P3), the third wave plate (P3) converts the first original light (L1 ) or the second original light (L2) to the second original light (L2) or the first original light (L1 ) and guides it to the fourth wave plate (P4), and the fourth wave plate (P4) converts the second original light (L2) or the first original light (L1 ) to the first original light (L1 ) or the second original light (L2).

15. The prism device (100) according to Claim 10, characterized in that the first subunit (41 ) comprises a seventh wave plate (P7) and a fifth wave plate (P5) both provided downstream from the fourth surface (S4), and a fourth coating (C4) provided downstream from the fifth wave plate (P5), and the second subunit (42) is a sixth wave plate (P6).