CN112147838B

CN112147838B - Two-color laser light source and laser projector

Info

Publication number: CN112147838B
Application number: CN202011053817.7A
Authority: CN
Inventors: 田有良
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2017-08-18
Filing date: 2017-08-18
Publication date: 2021-11-05
Anticipated expiration: 2037-08-18
Also published as: CN109407450B; CN112147837B; CN112147837A; CN109407450A; CN112147838A

Abstract

The invention discloses a bicolor laser light source and a laser projector, and belongs to the field of projection display. The first blue laser and the first red laser which are respectively emitted by the first blue laser and the first red laser which are positioned on the first side of the fluorescent wheel are transmitted through the polarization light-combining dichroic sheet, wherein the transmitted first blue laser irradiates the green fluorescent area of the fluorescent wheel to generate green fluorescent light, the second blue laser and the second red laser which are respectively emitted by the second blue laser and the second red laser which are positioned on the second side of the fluorescent wheel are transmitted through the fluorescent wheel and then enter the polarization light-combining dichroic sheet, the polarization light-combining dichroic sheet transmits the first red laser, reflects the second blue laser, the second red laser and the green fluorescent light, and the combined light output is realized. The invention is used for designing the bicolor laser light source.

Description

Two-color laser light source and laser projector

The invention is based on Chinese invention application 201710712832.X (2017-8-18), the invention name is: the application of the division of bicolor laser light source and laser projector.

Technical Field

The invention relates to the field of projection display, in particular to a bicolor laser light source and a laser projector.

Background

Disclosure of Invention

In order to solve the problem that the speckle phenomenon of red laser is serious in the related art, the embodiment of the invention provides a bicolor laser light source and a laser projector. The technical scheme is as follows:

in one aspect, the invention provides a two-color laser light source, which at least comprises a first blue laser, a second blue laser, a first red laser, a second red laser, a fluorescent wheel and a light combining component, wherein the fluorescent wheel is provided with a green fluorescent region;

the light combining component is used for transmitting second blue laser emitted by the second blue laser and green fluorescence emitted by the fluorescence wheel to the light collecting component, wherein the green fluorescence is generated by irradiating the green fluorescence area with first blue laser emitted by the first blue laser;

the light combining component is also used for transmitting first red laser light emitted by the first red laser and second red laser light emitted by the second red laser to the light collecting component;

the polarization direction of the first red laser light is perpendicular to the polarization direction of the second red laser light.

In another aspect, the present invention provides a laser projector comprising the two-color laser light source of any one of the above aspects.

The technical scheme provided by the embodiment of the invention has the following beneficial effects:

according to the two-color laser light source and the laser projector provided by the embodiment of the invention, the red laser collected by the light combination component is the light combination of the first red laser and the second red laser with the polarization directions perpendicular to each other, and the superposition of the two polarized lights can form the superposition of phase patterns when an image is projected, so that more independent random phase patterns are generated, the speckle effect of the red laser is effectively weakened, and the optical quality of the two-color laser light source is improved.

Drawings

Fig. 1 is a schematic structural diagram of a two-color laser light source in the related art;

fig. 2 is a schematic structural diagram of a two-color laser light source according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another two-color laser light source provided in the embodiment of the present invention;

fig. 4 is a schematic diagram of a color filter wheel according to an embodiment of the present invention;

FIG. 5 is a schematic view of a fluorescent wheel provided in accordance with embodiments of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The laser light source is a light source that emits monochromatic coherent light beams with high brightness and high directivity, and has been gradually applied to the field of projection display in recent years due to many advantages of the laser light source.

As an example, the laser light source may be applied to a laser projector. The laser projector may emit light of at least one color to effect display of an image. The primary colors are "basic colors" that cannot be obtained by mixing and blending other colors. Other new colors can be produced by mixing the primary colors in different proportions. Laser projectors typically produce primary color light to effect the display of graphics. The colors generated by a general laser projector are three primary colors, i.e., red, green, and blue, and with the development of technology, the laser projector can also generate two primary colors or five primary colors, which is not limited in the embodiments of the present invention.

There are many laser light sources of the current laser projectors, and the laser light source may include: at least one laser, the laser light source can emit light of at least one color. Typically the laser light source may further comprise: a fluorescent wheel (also called a fluorescent color wheel) may be used as the wavelength conversion device. The laser light source can be a monochromatic laser light source (that is, including a laser and the laser produces a color), can also be double-colored laser light source (that is, including two lasers and every laser produces a color), thus send out the laser of one or two kinds of colors, be provided with phosphor powder on the fluorescence wheel, can be excited out the fluorescence of corresponding color, be used for forming three primary colors with the color of the laser that the laser sent out of laser together, as the projection light source provides the illumination for the ray apparatus part.

Compared with a monochromatic laser light source, the bicolor laser light source can improve the color purity, the color brightness and the color gamut of the light source and better meet the color requirement of laser projection.

An embodiment of the present invention provides a two-color laser light source, as shown in fig. 2, the laser light source at least includes:

a first blue laser 21a, a second blue laser 21b, a first red laser 22a and a second red laser 22b, a fluorescent wheel 23 and a light combining component 24, wherein the fluorescent wheel is provided with a green fluorescent region.

The light combining member 24 is configured to transmit the second blue laser light emitted by the second blue laser 21b and the green fluorescence light emitted by the fluorescence wheel 23 to the light collecting member 25, wherein the green fluorescence light is generated by irradiating the green fluorescence region with the first blue laser light emitted by the first blue laser 21 a.

The light combining member 24 is also configured to transmit the first red laser light emitted by the first red laser 22a and the second red laser light emitted by the second red laser 22b to the light collecting member 25.

Optionally, the fluorescent wheel 23 may further include a transmission region for transmitting the second blue laser light and the second red laser light to the light combining part 24.

Alternatively, the light collecting member may be a light bar.

It should be noted that the laser provided by the embodiment of the present invention may be a laser array.

As shown in fig. 2, the first blue laser 21a, the first red laser 22a, the light combining member 24 and the light collecting member 25 are disposed on a first side of the luminescent wheel 23, the second blue laser 21b and the second red laser 22b are disposed on a second side of the luminescent wheel 23, the light combining member 24 is disposed between the first blue laser 21a and the luminescent wheel 23, and the light combining member 24 is disposed between the first red laser 22a and the light collecting member 25.

Correspondingly, the polarization direction of the second blue laser is perpendicular to the polarization direction of the first blue laser, and the polarization direction of the second blue laser is parallel to the polarization direction of the second red laser, and the light combining member 24 is configured to transmit the first blue laser and the first red laser, and reflect the second blue laser and the second red laser.

Optionally, as shown in fig. 2, in the two-color laser light source provided in the embodiment of the present invention, a light beam shaping device may be disposed on one side of the light emitting surface of each laser, which is respectively a first light beam shaping device a, a second light beam shaping device B, a third light beam shaping device C, and a fourth light beam shaping device D. The beam shaping device can be a telescope system (in practical application, the telescope system can comprise a convex lens and a concave lens) for compressing the parallel laser emitted by the laser to reduce the area of the beam, and the compressed laser is still parallel laser, so that the transmittance of the parallel laser in a rear-end optical device can be improved.

Optionally, as shown in fig. 2, a fifth beam shaping device E may be disposed between the light combining component 24 and the fluorescent wheel 23, the fifth beam shaping device E may be composed of two lenses, the first blue laser emitted by the first blue laser is focused by the two lenses and then irradiates on the fluorescent wheel, and the green fluorescent light emitted by the fluorescent wheel enters the light combining component after being collimated by the two lenses, so as to improve uniformity of light emission. The fifth beam shaper E is further configured to collimate the second blue laser light and the second red laser light. Optionally, the fifth beam shaping device E may also be composed of one, three, or four lenses, and the number of lenses constituting the beam shaping device is not limited in the embodiment of the present invention.

Since the direction of the second blue laser light emitted by the second blue laser 21b is perpendicular to the direction of the second red laser light emitted by the second red laser 22b, as shown in fig. 2, the two-color laser light source may further include: a dichroic plate 26, the dichroic plate 26 being arranged on a second side of the fluorescent wheel 23, between the second blue laser 21b and the fluorescent wheel 23, the dichroic plate 26 being operable to transmit the second blue laser light and to reflect the second red laser light.

In the embodiment of the present invention, the dichroic plate 26 may be disposed at an included angle of 45 ° with respect to the second red laser 22b, so that the second red laser emitted by the horizontally disposed second red laser is reflected by the dichroic plate and then vertically enters the fluorescent wheel, so that the second red laser can be transmitted according to a predetermined optical path, thereby ensuring the stability of laser transmission.

The optical path transmission process of the two-color laser light source shown in fig. 2 includes: the first blue laser emitted by the first blue laser 21a is transmitted from the light combining part 24 after passing through the first beam shaping device a, and then is irradiated on the fluorescent wheel 23 through the fifth beam shaping device E to excite the green fluorescent powder to emit green fluorescent light, and the green fluorescent light is reflected and output by the light combining part 24 after passing through the fifth beam shaping device E; the second blue laser beam emitted from the second blue laser 21B is transmitted from the dichroic plate 26 to the fluorescent wheel 23 after passing through the second beam shaper B, and is reflected and output by the light combining member 24 after being transmitted from the fluorescent wheel 23 and passing through the fifth beam shaper E; the first red laser beam emitted from the first red laser 22a is transmitted and output from the light combining member 24 after passing through the third beam shaper C, the second red laser beam emitted from the second red laser 22b is reflected to the fluorescent wheel 23 by the dichroic plate 26 after passing through the fourth beam shaper D, the second red laser beam is transmitted from the fluorescent wheel 23, passes through the fifth beam shaper E and is reflected and output by the light combining member 24, and the combined light of the first red laser beam and the second red laser beam is the red laser beam finally output by the light combining member 24. The light of the three colors can be mixed to form white light after entering the light collecting part 25, and the illumination function of the bicolor laser light source is realized.

In summary, in the two-color laser light source provided by the embodiment of the invention, the red laser light collected by the light combining component is the combined light of the first red laser light and the second red laser light whose polarization directions are perpendicular to each other, and the superposition of the two polarized lights can form the superposition of the phase patterns when the image is projected, so that more independent random phase patterns are generated, the speckle effect of the red laser light is effectively reduced, and the optical quality of the two-color laser light source is improved.

In the embodiment of the invention, the first blue laser, the second blue laser, the first red laser and the second red laser are all turned on in a time sequence, and the turning-on time of the first red laser is the same as that of the second red laser. Optionally, the lighting time of the first blue laser, the second blue laser and the red laser are different.

As shown in fig. 3, the light combining member may include a polarization light-combining dichroic plate 241, the polarization light-combining dichroic plate 241 is disposed on the light incident side of the light collecting member 25, and the polarization light-combining dichroic plate 241 is configured to transmit the first blue laser light and the first red laser light and reflect the green fluorescence, the second blue laser light, and the second red laser light.

Optionally, the first red laser is p-polarized light, the second red laser is s-polarized light, the first blue laser is p-polarized light, and the second blue laser is s-polarized light. Accordingly, the polarization combining dichroic plate is arranged to transmit p-polarized light and reflect s-polarized light.

Alternatively, the first red laser beam is s-polarized light, the second red laser beam is p-polarized light, the first blue laser beam is s-polarized light, and the second blue laser beam is p-polarized light. Accordingly, the polarization combining dichroic plate is arranged to transmit s-polarized light and reflect p-polarized light.

The polarization combining dichroic plate may reflect green fluorescence.

Further, as shown in fig. 3, the laser light source may further include a color filter wheel 27, and the color filter wheel 27 is disposed between the polarization-combined dichroic plate 241 (light combining part) and the light incident side of the light collecting part 25, as shown in fig. 4, and may include a red filter region R, a blue filter region Z, and a green filter region G. The color filter wheel can transmit blue laser, red laser and green fluorescence in a time sequence when rotating.

Specifically, when the color filter wheel rotates, and when an irradiation area of the color filter wheel is a blue filter area, the second blue laser is lightened, and meanwhile, the first blue laser, the first red laser and the second red laser are not lightened; when the irradiation area of the color filter wheel is a red filter area, the first red laser and the second red laser are lightened, and the first blue laser and the second blue laser are not lightened simultaneously; when the irradiation area of the color filter wheel is a green filter area, the first blue laser is lightened, and the second blue laser, the first red laser and the second red laser are not lightened at the same time, so that the blue laser, the red laser and the green fluorescence are transmitted in a time sequence manner.

In the embodiment of the present invention, in order to enhance the speckle reduction effect, the region of the color filter wheel that can transmit red light is preferably a red filter region, but not limited thereto.

Optionally, as shown in fig. 3, the light combining component may further include a fixed diffusion sheet 242, where the fixed diffusion sheet is configured to homogenize the blue laser light emitted by the first blue laser, and since the blue laser light emitted by the first blue laser is excitation light of the fluorescent wheel, if the light beam is not homogenized, the light spot intensity distribution of the laser light is uneven, and the energy is concentrated, when the light beam directly enters the surface of the fluorescent wheel, the laser light spot with concentrated energy may burn the surface of the fluorescent wheel, damage the fluorescent wheel, and cause that the fluorescent wheel cannot be normally excited by the laser light to emit fluorescent light.

Still further, as shown in fig. 3, the light combining component may further include a focusing lens 243, and the focusing lens 243 is disposed between the polarization light combining dichroic plate 241 and the color filter wheel 27. When the light beam diffusion angle of the light transmitted or reflected by the polarization-combined dichroic plate is larger than the collection angle of the light collection component, the collection efficiency of the light is low, and the brightness of the projection light source is affected.

Optionally, in the color filter wheel provided in the embodiment of the present invention, the surfaces of the red filter region and the blue filter region may be provided with a diffuser, and the diffuser may be micron-sized particles.

As shown in fig. 5, the fluorescent wheel may include a green fluorescent region Y and a transmission region, the transmission region may include a red light diffusion region K and a blue light diffusion region Q, a surface of the green fluorescent region Y is provided with green phosphor, and surfaces of the red light diffusion region K and the blue light diffusion region Q are respectively provided with a diffuser, which is a micron-sized particle. When the fluorescent wheel rotates, the fluorescent wheel can emit green fluorescent light, transmit the second blue laser and transmit the second red laser in a time sequence.

In the embodiment of the present invention, in order to enhance the speckle reduction effect, it is preferable that the region that can transmit red light on the transmission region of the fluorescent wheel is a red light diffusion region, and the region that can transmit blue light is a blue light diffusion region, but the present invention is not limited thereto.

Note that the particle diameter of the diffuser provided on the surface of the fluorescent wheel is different from the particle diameter of the diffuser provided on the surface of the color filter wheel.

Due to the high coherence of the laser light, a speckle effect is inevitably generated. The speckle is that when a coherent light source irradiates a rough object, scattered light has a constant phase due to the same wavelength, and generates interference in a space, and some of the interference in the space is long and some of the interference is cancelled, so that the final result is that granular light and dark spots appear on a screen, that is, some unfocused spots flicker, and a dizzy feeling is easily generated after long-time viewing, which undoubtedly causes the reduction of the quality of a projected image and reduces the viewing experience of a user.

In the embodiment of the invention, when a second blue laser emitted by a second blue laser passes through a fluorescent wheel, the second blue laser is firstly diffused for the first time by a diffuser on a blue light diffusion area of the fluorescent wheel and then diffused for the second time by a diffuser on a blue filter area of a color filter wheel after entering a light combining part, and as the diameters of particles of the diffusers on the blue light diffusion area of the fluorescent wheel and the diffusers on the blue filter area of the color filter wheel are different, the diffusion angles of the second blue laser are different, so that more independent random phase patterns can be generated by the second blue laser; further, because the fluorescent wheel and the color filter wheel both rotate, the moving diffuser can further increase random phases, and can better destroy coherence of the blue laser, so that the laser light source for projection can form more independent random phase patterns on a projection image. The more the number of the independent random phase patterns is, the weaker the light and dark spot phenomenon is by utilizing the integral action of human eyes, thereby effectively weakening the speckle effect of the laser and improving the optical quality of the bicolor laser light source.

For example, the particle diameter of the diffuser disposed on the surface of the fluorescent wheel may be larger than the particle diameter of the diffuser disposed on the surface of the filter wheel, for example, the particle diameter of the diffuser disposed on the surface of the fluorescent wheel is 100 micrometers, and the particle diameter of the diffuser disposed on the surface of the filter wheel is 30 micrometers. The diffuser arranged on the surface of the fluorescent wheel can firstly scatter the laser, and then the diffuser arranged on the surface of the color filter wheel can accurately rearrange the phase of the laser.

It should be noted that the particle diameter of the diffuser disposed on the surface of the fluorescent wheel may also be smaller than the particle diameter of the diffuser disposed on the surface of the filter wheel, for example, the particle diameter of the diffuser disposed on the surface of the fluorescent wheel is 30 micrometers, and the particle diameter of the diffuser disposed on the surface of the filter wheel is 100 micrometers.

Further, compared with a blue laser, the red laser in the two-color laser light source provided by the embodiment of the invention has a longer coherence length and higher coherence, so that the speckle phenomenon is more serious, and the red laser in the two-color laser light source provided by the embodiment of the invention is a combined light of the first red laser and the second red laser, and because the first red laser and the second red laser are different polarized lights, for example, the first red laser is a p-polarized light and the second red laser is an s-polarized light, when an image is projected, the superposition of the two polarized lights can form superposition of phase patterns, so that more independent random phase patterns are generated, and the speckle effect of the red laser is further reduced.

Embodiments of the present invention provide a laser projector that may include a two-color laser light source as shown in fig. 2 or 3.

The invention is not to be considered as limited to the particular embodiments shown and described, but is to be understood that various modifications, equivalents, improvements and the like can be made without departing from the spirit and scope of the invention.

Claims

1. A bi-color laser light source, the laser light source comprising:

the fluorescent wheel is provided with a green fluorescent area and a transmission area;

the first blue laser and the second blue laser are respectively arranged on the first side and the second side of the fluorescent wheel and respectively emit first blue laser and second blue laser with vertical polarization directions;

the first red laser and the second red laser are respectively arranged on the first side and the second side of the fluorescent wheel and respectively emit first red laser and second red laser with vertical polarization directions;

wherein the first blue laser and the first red laser are arranged perpendicular to each other;

the second blue laser and the second red laser are arranged vertically to each other;

the polarization light-combination dichroic plate is arranged at the intersection of the first blue laser, the second blue laser, the first red laser and the second red laser;

the polarization-combined dichroic plate is used for transmitting and irradiating the first blue laser to a green fluorescence area of the fluorescence wheel and generating green fluorescence, and reflecting the green fluorescence to a light collection component when the green fluorescence is reflected by the fluorescence wheel to irradiate the polarization-combined dichroic plate;

and the polarization-combining dichroic plate is further configured to reflect the second blue laser light and the second red laser light to a light collection member after the second blue laser light and the second red laser light are transmitted from the second side of the fluorescent wheel through the transmission region of the fluorescent wheel and are incident on the polarization-combining dichroic plate;

the polarization-combining dichroic plate is further configured to transmit the first red laser light to the light collection component.

2. The laser light source according to claim 1, wherein the polarization directions of the first blue laser light and the first red laser light are parallel;

the polarization directions of the second blue laser and the second red laser are parallel.

3. The laser light source of claim 1, further comprising a dichroic plate on a second side of the fluorescent wheel, the dichroic plate configured to transmit the second blue laser light and reflect the second red laser light.

4. The laser light source according to claim 1, wherein the transmission region includes a red light diffusion region and a blue light diffusion region;

the red light diffusion region is used for transmitting the second red laser, and the blue light diffusion region is used for transmitting the second blue laser.

5. The laser light source of claim 4, further comprising a color filter wheel disposed between the dichroic polarizing combiner and the light incident side of the light collecting member, the color filter wheel comprising a red filter zone, a blue filter zone, and a green filter zone for transmitting red laser light, blue laser light, and green fluorescent light, respectively, wherein a surface of the red filter zone and the blue filter zone is provided with a diffuser.

6. The laser light source of claim 5, further comprising a focusing lens disposed between the polarization-combining dichroic sheet and the color filter wheel;

the focusing lens is used for respectively focusing the first red laser light transmitted by the polarization beam-combining dichroic filter, the reflected green fluorescent light, the reflected second blue laser light and the reflected second red laser light.

7. The laser light source according to any one of claims 1 to 6, wherein the first red laser light is p-polarized light, the second red laser light is s-polarized light, the first blue laser light is p-polarized light, and the second blue laser light is s-polarized light;

or the first red laser is s-polarized light, the second red laser is p-polarized light, the first blue laser is s-polarized light, and the second blue laser is p-polarized light.

8. The laser light source according to any one of claims 1 to 6, wherein a beam shaping device is disposed on a side of the light emitting surface of each laser.

9. The laser light source according to any one of claims 1 to 6, wherein the first blue laser, the second blue laser, the first red laser, and the second red laser are all turned on in time sequence;

and the lighting time of the first red laser and the second red laser is the same.

10. A laser projector comprising the two-color laser light source according to any one of claims 1 to 9.