A light source system and a projection system

Abstract

The present application discloses an optical system and a projection system. The light source system includes: a first light source, a second light source, a light combining component, a fly-eye lens group and a collecting lens, wherein the first light source is used to emit a first light beam; the second light source is used to emit a second light beam, and the optical extension of the first light beam is greater than that of the second light beam; the light combining component is used to combine the first light beam and the second light beam; the fly-eye lens group includes a first fly-eye lens and a second fly-eye lens, and is used to homogenize the first and second light beams after the light combination; the collecting lens is located on the side of the fly-eye lens away from the light combining component, and is used to focus the first and second light beams after the light combination, wherein the second fly-eye lens is located between the first fly-eye lens and the collecting lens, and is set away from the focus of the collecting lens. The present application improves the uniformity of color and brightness of the light source system and improves the safety of the light source system by setting the second fly-eye lens away from the focus of the collecting lens.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to a light source system and a projection system. Background Art

[0002] At present, laser plus fluorescent light sources are beginning to be more and more widely used in the field of display (such as projection). For example, some light sources need to consider combining red, green and blue lasers with yellow fluorescence (or red fluorescence + green fluorescence) excited by blue light. The light source also needs to consider light homogenization while combining the light. In related technologies, the light homogenization scheme mostly uses square rods or compound eye lenses.

[0003] The inventors of the present application discovered during a long research and development process that in current light source systems, when a compound eye lens is used to homogenize the combined light of laser and fluorescence, the laser angular distribution of the homogenized light spot will become discrete, affecting the brightness uniformity, color uniformity and safety of the light source system. Summary of the invention

[0004] The main technical problem solved by the present application is to provide a light source system and a projection system, which reduce the discreteness of the angular distribution of the homogenized light spot by sacrificing the telecentric characteristic, so as to improve the brightness and color uniformity of the light source system and the safety of the light source.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a light source system, which includes: a first light source, used to emit a first light beam; a second light source, used to emit a second light beam, the optical expansion of the first light beam is greater than that of the second light beam; a light combining component, used to combine the first light beam and the second light beam; a fly-eye lens group, including a first fly-eye lens and a second fly-eye lens, used to homogenize the first light beam and the second light beam after combining; a collecting lens, located on the side of the fly-eye lens away from the light combining component, used to focus the first light beam and the second light beam after homogenization, wherein the second fly-eye lens is located between the first fly-eye lens and the collecting lens, and is set away from the focus of the collecting lens.

[0006] Further, the front focal plane of the collecting lens is located upstream of the optical path of the second fly-eye lens.

[0007] Furthermore, the first fly-eye lens includes first microlens units arranged in an array; the second fly-eye lens includes second microlens units arranged in an array; the first microlens units correspond to the second microlens units one by one, and the first microlens units and the second microlens units have the same structure.

[0008] Furthermore, the widening angle δ of the light emitted by a single second microlens unit after passing through the collecting lens satisfies the following formula:

[0009] ,

[0010] Wherein, a is the length of the longer side of the second microlens unit, f BFL is the equivalent back focal length of the collecting lens.

[0011] Furthermore, the collecting lens is a single lens.

[0012] Furthermore, the collecting lens is a combination of at least two lenses.

[0013] Furthermore, the light source system also includes a first relay lens, which is located between the light combining component and the fly-eye lens group and is used to focus the combined first light beam and the second light beam to a first preset area of ​​the first fly-eye lens.

[0014] Furthermore, the first light source is a fluorescent light source, the second light source is a laser light source, and the laser light source includes at least one green laser emitting green excitation light, at least one red laser emitting red excitation light, and at least one blue laser emitting blue excitation light.

[0015] Furthermore, the light source system also includes a second relay lens, and the relay lens group is located between the second light source and the light combining component, and is used to focus the second light beam emitted by the second light source to a second preset area of ​​the light combining component.

[0016] In order to solve the above-mentioned technical problems, another technical solution adopted in the present application is: to provide a projection system, which includes a light source system of any of the above-mentioned embodiments and a spatial light modulator located on the light output path of the light source system, and the spatial light modulator is used to modulate the light beam emitted by the light source system into image light carrying image information.

[0017] The beneficial effects of the present application are as follows: different from the prior art, the light source system of the present application includes a first light source for emitting a first light beam, a second light source for emitting a second light beam, a light combining component, a compound eye lens group and a collecting lens, the optical expansion of the first light beam is greater than that of the second light beam, the light combining component is used to combine the first light beam and the second light beam to obtain a combined light after the first light beam and the second light beam are combined, the compound eye lens group is used to homogenize the combined light after the first light beam and the second light beam are combined, and the collecting lens is used to focus the first light beam and the second light beam after homogenization, wherein the second compound eye lens is set to deviate from the focal point of the collecting lens, in this way, the first light beam and the second light beam after homogenization by the compound eye lens group can still have a certain diffusion angle after passing through the collecting lens, so that the energy distribution of the first light beam and the second light beam after homogenization is relatively consistent; that is, the present application sacrifices the high beam characteristics to weaken the discreteness of the angular distribution of the homogenized second light beam spot, which is beneficial to improving the uniformity of the brightness and color of the light source system and the safety of the light source system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of an embodiment of a light source system provided by the present application;

[0019] Figure 2 yes Figure 1 A schematic diagram of the optical path structure of a compound eye lens group and a collecting lens in one embodiment;

[0020] Figure 3 yes Figure 1 Schematic diagram of the optical path structure in the compound eye lens group;

[0021] Figure 4 It is a schematic diagram of the structure of a double telecentric compound eye lens and a collecting lens in the related art;

[0022] Figure 5 yes Figure 1 A schematic diagram of the distribution of a compound eye lens group and a collecting lens in an embodiment;

[0023] Figure 6 It is a structural schematic diagram of an embodiment of a projection system provided by the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. The term "or / and" used herein includes any and all combinations of one or more of the associated listed items.

[0026] See also Figure 1 , Figure 1 It is a structural schematic diagram of an embodiment of a light source system provided in the present application. The light source system of this embodiment includes at least two light sources, namely a first light source 1 and a second light source 2. The first light source 1 is used to emit a first light beam, and the second light source 2 is used to emit a second light beam, wherein the optical expansion of the first light beam is greater than that of the second light beam.

[0027] The first light source 1 refers to a light source with a large optical extension of the emitted light beam, for example, the first light source 1 may be a fluorescent light source, and the first light beam may be a fluorescent light beam; the second light source 2 refers to a light source with a small optical extension of the emitted light beam, for example, the second light source 2 may be a laser light source, and the second light beam may be a laser light beam. In a specific embodiment, the first light source 1 may include an excitation light source (not shown) and a fluorescent color wheel (not shown), and the excitation light emitted by the excitation light source, such as a blue laser, is incident on the fluorescent color wheel, and the fluorescent color wheel generates corresponding fluorescence under the irradiation of the excitation light, for example, the first light beam may be yellow fluorescence, or the first light beam may also be red fluorescence and green fluorescence. The second light source 2 may include a red laser 201 that emits red excitation light, a green laser 202 that emits green excitation light, and a blue laser 203 that emits blue excitation light.

[0028] like Figure 1 As shown, the light source system further includes a light combining component 3 , a fly-eye lens group 4 and a collecting lens 5 .

[0029] Specifically, the light combining component 3 is used to combine the first light beam and the second light beam with different optical etendues to obtain a combined light after the first light beam and the second light beam are combined. Figure 1 As shown, the light combining can utilize the idea that the optical expansion of the second light beam is smaller than that of the first light beam, and a reflective film 31 is set on the light combining component 3 to combine the first light beam and the second light beam. Since the optical expansion of the second light beam is smaller than that of the first light beam, the second light beam can be incident on the reflective film 31 of the light combining component 3 through beam control, and then emitted after reflection; while the optical expansion of the first light beam is relatively large, and the first light beam can be incident on the peripheral transmission area of ​​the light combining component 3 through beam control, and then emitted after transmission. The first light beam incident on the reflective film 31 of the light combining component 3 is reflected, which will lead to a decrease in the efficiency of the first light beam. Therefore, the area of ​​the reflective film can be designed to be as small as possible.

[0030] The fly-eye lens group 4 includes a first fly-eye lens 41 and a second fly-eye lens 42, which are used to homogenize and shape the first light beam and the second light beam after light combination, and the shaping can form a predetermined light spot shape, such as a rectangle, a square, etc. Among them, the first fly-eye lens 41 is located between the light combination component 3 and the second fly-eye lens 42, that is, the combined light after the first light beam and the second light beam are combined passes through the first fly-eye lens 41 and the second fly-eye lens 42 in sequence for homogenization and shaping.

[0031] The fly-eye lens group 4 can be a single double fly-eye lens or a double single fly-eye lens. Specifically, a single double fly-eye lens refers to a single lens having two opposite surfaces provided with a plurality of micro lenses. The two opposite surfaces provided can be the first fly-eye lens 41 and the second fly-eye lens 42 in this embodiment, respectively.

[0032] Preferably, the fly-eye lens group 4 may also be a double-piece single fly-eye lens, that is, the first fly-eye lens 41 and the second fly-eye lens 42 are arranged in a mirror image. The first fly-eye lens 41 includes a first microlens unit 411 arranged in an array; the second fly-eye lens 42 includes a second microlens unit 421 arranged in an array, the first microlens unit 411 corresponds to the second microlens unit 421, and the correspondingly arranged first microlens unit 411 and second microlens unit 421 may be convex lenses of exactly the same shape.

[0033] More preferably, the distance between the first fly-eye lens 41 and the second fly-eye lens 42 is equal to the focal length of the first microlens unit 411 or the second microlens unit 421. In this way, the first microlens unit 411 can be imaged on the second microlens unit 421 to achieve uniform output of the light beam.

[0034] The collecting lens 5 is located on the side of the fly-eye lens group 4 away from the light combining component 3, and is used to focus the first light beam and the second light beam after homogenization. Figure 2 As shown, Figure 2 yes Figure 1 Schematic diagram of the optical path structure of an embodiment of the compound eye lens group 4, the light beam emitted by the first microlens unit 411 propagates parallel to the optical axis after passing through the corresponding second microlens unit 421, and then converges to the back focal plane BFP of the collecting lens 5 after passing through the collecting lens 5. When the collecting lens 5 is a double lens group, after the light beam passes through the first principal plane PP1 of the double lens group, it is emitted from the second principal plane PP2 of the double lens group and then focused on the back focal plane BFP of the double lens group.

[0035] Due to the difference in optical etendue, the optical etendue of the first light beam is larger, so the spot area of ​​the first light beam in the light combining component 3 is larger. In comparison, the optical etendue of the second light beam is smaller. Figure 3 As shown, after passing through the first fly-eye lens 41 , the first light beam can have a larger expanded spot on the second fly-eye lens 42 , and the light energy density distribution is more uniform; while the second light beam has a smaller spot on the second fly-eye lens 42 , and the light energy density distribution is uneven.

[0036] In this embodiment, the second fly-eye lens 42 is located between the first fly-eye lens 41 and the collecting lens 5, and is set away from the focus of the collecting lens 5. That is to say, the front focal plane FFP of the collecting lens 5 is adjusted to the upstream of the optical path of the second fly-eye lens 42, or the front focal plane FFP of the collecting lens 5 is adjusted to the downstream of the optical path of the second fly-eye lens 42, so that the distance between the second fly-eye lens 42 and the collecting lens 5 is less than or greater than the focal length of the collecting lens 5. In this way, the second light beam after being homogenized by the fly-eye lens group 4 can still have a certain diffusion angle after passing through the collecting lens 5, so that the energy distribution of the first light beam and the second light beam after homogenization is relatively consistent, so as to improve the uniformity of the brightness and color of the light source system and improve the safety of the light source.

[0037] Specifically, Figure 4 As shown, if the distance between the collecting lens 5 and the second fly-eye lens 42 is equal to the focal length of the collecting lens 5, that is, the front focal plane FFP of the collecting lens 5 and the second fly-eye lens 42 overlap each other in space, then the light beam incident on the first microlens unit 411 parallel to the optical axis converges to the front focal plane FFP of the collecting lens 5 after the second fly-eye lens 42, and will be irradiated to the back focal plane BFP of the collecting lens 5 in a parallel manner. In other words, the angular distribution of the light beam incident on the first fly-eye lens 41 is mapped to the angular distribution of the back focal plane BFP, and the angular distribution corresponding to the back focal plane BFP of the collecting lens 5 presents a certain separation. It can be seen that the angular distribution of the homogenized light spot 8 is discrete points, and discretization occurs. Specifically, the energy of the second light beam is too concentrated within a certain angle range, while the energy distribution is less at other angles, resulting in a ratio of the first light beam to the second light beam at a certain angle that is more than the ideal value, while at other angles, the ratio of the first light beam to the second light beam is less than the ideal value, resulting in brightness uniformity and color uniformity problems. This will affect the brightness uniformity, color uniformity and safety of the light source system.

[0038] like Figure 5 As shown, in this embodiment, by adjusting the position of the second fly-eye lens 42 to a position deviating from the focus of the collecting lens 5, the main light incident on the back focal plane BFP of the collecting lens 5 no longer propagates parallel to the optical axis, but has a certain diffusion angle, so that the angular distribution discreteness of the homogenized light spot 8 is better solved.

[0039] Preferably, the front focal plane FFP of the collecting lens 5 is adjusted to the upstream direction of the optical path of the second fly-eye lens 42, so that the distance between the second fly-eye lens 42 and the collecting lens 5 is smaller than the focal length of the collecting lens 5, thereby making the separated light spot converged on the second fly-eye lens 42 within one focal length of the collecting lens 5, and then forming an image after passing through the collecting lens 5, which can better homogenize the angular distribution of the light beam on the back focal plane BFP of the collecting lens 5.

[0040] Specifically, in this embodiment, the widening angle δ of the light beam emitted by the single second microlens unit 421 after passing through the collecting lens 5 is a function of the equivalent front focal length of the collecting lens 5 and the distance d1 between the front focal plane FFP of the collecting lens 5 and the second fly-eye lens array. Preferably, δ satisfies the following formula:

[0041] ,

[0042] Wherein, a is the length of the longer side of the second microlens unit 421, and f BFL is the equivalent back focal length of the collecting lens 5. In this way, the light spot 8 on the back focal plane of the collecting lens 5 can present a relatively uniform angular distribution.

[0043] Optionally, the collecting lens 5 may be a single lens. When the collecting lens 5 is a single lens, the structure of the entire light source system can be simpler, the design is convenient, and the cost is saved.

[0044] In other embodiments, the collecting lens 5 may also be a combination of at least two lenses. When the collecting lens 5 is a combination of at least two lenses, it may also be equivalent to a single lens. In a specific embodiment, the collecting lens 5 may be a simple double-thin lens group, the first principal plane PP1 of the collecting lens 5 coincides with the first lens, and the second principal plane PP2 of the collecting lens 5 coincides with the position of the second lens, wherein the focal length of the first lens is f1, the focal length of the second lens is f2, and the distance between the first principal plane PP1 and the second principal plane PP2 is d, then the calculation formula of the equivalent focal length fEFL of the collecting lens 5 is: , the calculation formula of the equivalent back focal length fBFL of the collecting lens 5 is: , the equivalent front focal length fFEL of the collecting lens 5 is: .

[0045] When the collecting lens 5 is a combination of multiple lenses, the distance between the collecting lens 5 and the second fly-eye lens 42 is relatively short, and the volume of the entire light source system can be reduced.

[0046] In this embodiment, the second fly-eye lens 42 is set at a position deviating from the focus of the collecting lens 5, so that the second light beam after being homogenized by the fly-eye lens group 4 still has a certain diffusion angle after passing through the collecting lens 5, so that the energy distribution of the first light beam and the second light beam after homogenization is relatively consistent; the present application sacrifices the high beam characteristics to a certain extent to weaken the discreteness of the angular distribution of the homogenized light spot of the second light beam, which is beneficial to improve the brightness and color uniformity of the light source system and improve the safety threshold of the light source system, so that the light source system has stronger applicability.

[0047] Alternatively, if Figure 1As shown, the light source system also includes a first relay lens 6, which is located between the light combining component 3 and the fly-eye lens group 4, and is used to focus the first light beam and the second light beam after combining to the first preset area of ​​the first fly-eye lens 41. In this embodiment, the first relay lens 6 straightens the first light beam and the second light beam and then enters the fly-eye lens group 4. The first light beam and the second light beam after combining by the light combining component 3 are both focused and emitted by the first relay lens 6 to improve the utilization rate of the light beams by the subsequent optical path system. That is, after the first light beam and the second light beam after combining pass through the first relay lens 6, the optical axes of the two light beams roughly coincide, and the divergence angles of the two light beams after combining also become smaller, which is beneficial to the subsequent light uniformity processing of the fly-eye lens group 4.

[0048] Alternatively, if Figure 1 As shown, the light source system may further include a second relay lens 7, which is located between the second light source 2 and the light combining component 3, and is used to focus the second light beam emitted by the second light source 2 to a second preset area of ​​the light combining component 3. In this embodiment, the second light beam can be incident on the reflective film 31 of the light combining component 3 through the light beam control of the second relay lens 7.

[0049] The light source system of this embodiment can effectively improve the problem of discretization of angular distribution after the first light beam and the second light beam are combined due to different optical etendues, which is beneficial to improving the uniformity of brightness and color of the light source system, improving the safety threshold of the light source system, and enhancing the applicability of the light source system.

[0050] like Figure 6 As shown, the present application further provides a projection system, which includes a light source system 61 of any of the above embodiments and a spatial light modulator 62 located on the light output path of the light source system 61 .

[0051] The spatial light modulator 62 is used to modulate the light beam emitted by the light source system 61 into image light carrying image information. The spatial light modulator 62 can be a single-chip or multi-chip spatial light modulator.

[0052] The spatial light modulator 62 may be a reflective display element, for example, the spatial light modulator 62 may be a DMD (Digital Micro mirror Device). In other alternative embodiments, the spatial light modulator 62 may also be an LCOS (Liquid Crystal On Silicon) or an LCD (Liquid Crystal Display).

[0053] For the specific structure of the light source system 61 , please refer to the relevant descriptions in the text and drawings of the above embodiments, which will not be described again here.

[0054] In the projection system of this embodiment, the second compound eye lens of the light source system 61 is set away from the focal point of the collecting lens. The problem of the discrete distribution of the homogenized spot angle of the second light beam after combining due to the different optical expansion amounts of the first light beam and the second light beam is improved by sacrificing the telecentric characteristic. The brightness and color uniformity of the light source system 61 can be improved, thereby improving the effect of the projection system.

[0055] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A light source system, characterized in that: The light source system comprises: A first light source, configured to emit a first light beam; a second light source, configured to emit a second light beam, wherein the optical etendue of the first light beam is greater than that of the second light beam; A light combining component, used for combining the first light beam and the second light beam; A fly-eye lens group, comprising a first fly-eye lens and a second fly-eye lens, for homogenizing the first light beam and the second light beam after light combination; A collecting lens is located on a side of the fly-eye lens group away from the light combining component, and is used to focus the first light beam and the second light beam after homogenization. Wherein, the second fly-eye lens is located between the first fly-eye lens and the collecting lens, and is set away from the focal point of the collecting lens.

2. The light source system according to claim 1, characterized in that: The front focal plane of the collecting lens is located upstream of the optical path of the second fly-eye lens.

3. The light source system according to claim 2, characterized in that: The first fly-eye lens comprises first micro-lens units arranged in an array; The second fly-eye lens comprises second microlens units arranged in an array; The first microlens unit corresponds to the second microlens unit one by one, and the first microlens unit and the second microlens unit have the same structure.

4. The light source system according to claim 3, characterized in that: The widening angle δ of the light emitted by a single second microlens unit after passing through the collecting lens satisfies the following formula: ， Wherein, a is the length of the longer side of the second microlens unit, f BFL is the equivalent back focal length of the collecting lens.

5. The light source system according to claim 1, characterized in that: The collecting lens is a single lens.

6. The light source system according to claim 1, characterized in that: The collecting lens is a combination of at least two lenses.

7. The light source system according to claim 1, characterized in that: The light source system further includes a first relay lens, which is located between the light combining component and the fly-eye lens group and is used to converge the first light beam and the second light beam after light combining to a first preset area of ​​the first fly-eye lens.

8. The light source system according to claim 1, characterized in that: The first light source is a fluorescent light source, the second light source is a laser light source, and the laser light source includes at least one green laser emitting green excitation light, at least one red laser emitting red excitation light, and at least one blue laser emitting blue excitation light.

9. The light source system according to claim 8, characterized in that: The light source system further includes a second relay lens, which is located between the second light source and the light combining component and is used to focus the second light beam emitted by the second light source to a second preset area of ​​the light combining component.

10. A projection system, characterized in that: The projection system comprises the light source system according to any one of claims 1 to 9 and a spatial light modulator located on the light output path of the light source system, wherein the spatial light modulator is used to modulate the light beam emitted by the light source system into image light carrying image information.

Images