Light module for a projection apparatus and method for generating the blue component in a light module for a projection apparatus

1. A light module for a projection apparatus, comprising:

a laser apparatus adapted to emit linearly polarized radiation in a blue wavelength range;

a luminous wheel arranged in the beam path of the radiation emitted by the laser apparatus;

a first beam splitter arranged in the beam path of the radiation emitted by the laser apparatus between the laser apparatus and the luminous wheel;

a focusing apparatus arranged in the beam path of the radiation emitted by the laser apparatus between the first beam splitter and the luminous wheel; and

at least one polarization manipulation apparatus, arranged in the beam path of the radiation emitted by the laser apparatus between the first beam splitter and the luminous wheel, which is adapted to rotate the polarization of radiation that has passed through it twice in different directions through 90°,

wherein the first beam splitter is arranged in the beam path of radiation in the blue wavelength range which has passed twice through the polarization manipulation apparatus in different directions.

2. The light module as claimed in claim 1 , wherein the first beam splitter is arranged such that the angle of incidence of the radiation emitted by the laser apparatus is between 30° and 60°.

3. The light module as claimed in claim 1 , wherein the luminous wheel has at least one sector coated with a phosphor, wherein the at least one phosphor is adapted to emit, when it is excited by radiation in the blue wavelength range, radiation in another wavelength range.

4. The light module as claimed in claim 1 , wherein the first beam splitter is configured

to transmit radiation below a prespecifiable wavelength and with the polarization as is emitted by the laser apparatus, and

to reflect radiation below the prespecifiable wavelength and with a polarization as is present after two passages through the polarization manipulation apparatus in different directions.

5. The light module as claimed in claim 4 , wherein the luminous wheel has at least one sector which is configured to reflect radiation at least in the blue wavelength range, and wherein the first beam splitter is furthermore configured to reflect radiation above the prespecifiable wavelength and with a polarization as is present after two passages through the polarization manipulation apparatus in different directions.

6. The light module as claimed in claim 4 , wherein the luminous wheel has at least one sector which is configured to transmit radiation at least in the blue wavelength range,

wherein the first beam splitter is furthermore configured to reflect radiation above the prespecifiable wavelength and with a polarization as is present after two passages through the polarization manipulation apparatus in different directions, and

wherein the light module furthermore has a mirror, which is configured and arranged to reflect radiation that has passed through the at least one sector back onto the at least one sector.

7. The light module as claimed in claim 6 , wherein the mirror is configured to be curved.

8. The light module as claimed in claim 6 , wherein the mirror is configured as a plane mirror, and wherein the light module comprises a collimating apparatus arranged in the beam path between the luminous wheel and the mirror.

9. The light module as claimed in claim 5 , wherein the polarization manipulation apparatus is arranged in the beam path of the radiation emitted by the laser apparatus between the first beam splitter and the focusing apparatus.

10. The light module as claimed in claim 6 , wherein the polarization manipulation apparatus is arranged in the beam path of the radiation emitted by the laser apparatus between the luminous wheel and the mirror.

11. The light module as claimed in 1 , wherein the luminous wheel has at least one sector which is configured to reflect radiation at least in the blue wavelength range;

wherein the light module furthermore comprises:

a second beam splitter, which is arranged in the beam path between the polarization manipulation apparatus and the focusing apparatus, wherein the second beam splitter is configured to transmit radiation below the prespecifiable wavelength and to reflect radiation above the prespecifiable wavelength;

a mirror, which is arranged in the beam path of radiation that has been reflected by the first beam splitter; and

a third beam splitter which is arranged in the beam path of radiation that has been reflected by the second beam splitter and which is also arranged in the beam path of radiation that has been reflected by the mirror, wherein the third beam splitter is adapted to transmit radiation above the prespecifiable wavelength and to reflect radiation below the prespecifiable wavelength.

12. The light module as claimed in claim 4 , wherein the prespecifiable wavelength is at least 448 nm.

13. The light module as claimed in claim 1 , wherein the polarization manipulation apparatus is a λ/4 wave plate or a Faraday rotator.

14. The light module as claimed in claim 1 , wherein the radiation emitted by the laser apparatus is one or both of polarized parallel to the plane of incidence of the first beam splitter and polarized perpendicular to the plane of incidence of the first beam splitter.

15. A method for generating the blue component in a light module for a projection apparatus, wherein the light module comprises a laser apparatus adapted to emit linearly polarized radiation in the blue wavelength range, a luminous wheel arranged in the beam path of the radiation emitted by the laser apparatus, a first beam splitter arranged in the beam path of the radiation emitted by the laser apparatus between the laser apparatus and the luminous wheel, and a focusing apparatus arranged in the beam path of the radiation emitted by the laser apparatus between the first beam splitter and the luminous wheel;

wherein the method comprises the steps of:

arranging, in the beam path of the radiation emitted by the laser apparatus between the first beam splitter and the luminous wheel, a polarization manipulation apparatus which is adapted to rotate the polarization of radiation that has passed through it twice through 90°; and

arranging the first beam splitter such that it is also located in the beam path of radiation in the blue wavelength range which has passed twice through the polarization manipulation apparatus in different directions.

16. The light module as claimed in claim 1 , wherein the first beam splitter is arranged such that the angle of incidence of the radiation emitted by the laser apparatus is 45°.

17. The light module as claimed in claim 1 , wherein the prespecifiable wavelength is 462 to 465 nm.

18. A light module for a projection apparatus, comprising:

a laser apparatus adapted to emit linearly polarized radiation in a blue wavelength range;

a luminous wheel arranged in the beam path of the radiation emitted by the laser apparatus;

a first beam splitter arranged in the beam path of the radiation emitted by the laser apparatus between the laser apparatus and the luminous wheel;

a focusing apparatus arranged in the beam path of the radiation emitted by the laser apparatus between the first beam splitter and the luminous wheel; and

at least one polarization manipulation apparatus, which is adapted to rotate the polarization of radiation that has passed through it twice in different directions through 90°,

wherein:

the first beam splitter is arranged in the beam path of radiation in the blue wavelength range which has passed twice through the polarization manipulation apparatus in different directions,

the first beam splitter is configured to transmit radiation that is in the blue wavelength range and has the polarization as is emitted by the laser apparatus,

the first beam splitter is configured to reflect radiation that is in the blue wavelength range and has a polarization as is present after two passages through the polarization manipulation apparatus in different directions, and

the first beam splitter is configured to reflect radiation having a wavelength above the blue wavelength range.