CN117616332A

CN117616332A - Projection apparatus

Info

Publication number: CN117616332A
Application number: CN202280047132.2A
Authority: CN
Inventors: 罗李浩男; 李巍
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2021-06-29
Filing date: 2022-06-27
Publication date: 2024-02-27
Also published as: CN113406850A; CN113406850B

Abstract

A projection device (1), the projection device (1) comprising a light source assembly (10) comprising a plurality of light sources and a light combining lens group (200); the plurality of light sources includes a first light source (11), a second light source (12), a third light source (13), and a fourth light source (14), the first light source (11) is configured to emit at least light of a first wavelength band, the second light source (12) is configured to emit at least light of a second wavelength band, the third light source (13) is configured to emit at least light of a third wavelength band, the light combining lens set (200) includes a first light combining lens (21), a second light combining lens (22), and a third light combining lens (23), and the third light combining lens (23) is configured to reflect at least a portion of the light of the third wavelength band or the second wavelength band to excite at least one of the second light source (12) or the third light source (13).

Description

Projection apparatus

The present application claims priority from the chinese patent application No. 202121476502.3 filed on the year 2021, month 06 and 29; priority of chinese patent application No. 202110729252.8 filed on 29 of 2021, 06, is incorporated herein by reference in its entirety.

Technical Field

The disclosure relates to the technical field of projection display, and in particular relates to a projection device.

Background

The projection display technology controls a light source through image information, enlarges and displays an image on a projection screen using an optical system and a projection space. With the development of projection display technology, the projection display technology is gradually applied to the fields of business activities, conference exhibitions, scientific education, traffic management, centralized monitoring, advertisement entertainment and the like.

Disclosure of Invention

Some embodiments of the present disclosure provide a projection device. The projection device includes a light source assembly. The light source assembly includes a plurality of light sources and a light combining lens set. The plurality of light sources includes a first light source, a second light source, a third light source, and a fourth light source. The first light source is configured to emit at least light of a first wavelength band, and an emitting direction of the first light source is parallel to the first direction. The second light source is configured to emit at least light of a second wavelength band. The third light source is configured to emit light of at least a third wavelength band, and light emitting directions of the second light source and the third light source are parallel to a second direction, which is perpendicular to the first direction. The fourth light source is configured to emit first excitation light to excite the second light source to emit light of the second wave band, and the light emitting direction of the fourth light source is opposite to the light emitting direction of the second light source. The light converging lens group comprises a first light converging lens, a second light converging lens and a third light converging lens. The first light converging lens is arranged at the intersection of the emergent light of the first light source and the emergent light of the second light source. The first light combiner is configured to transmit light in the first wavelength band and reflect light in the second wavelength band. The second light converging lens is arranged at the junction of the emergent light of the first light converging lens and the emergent light of the third light source. The second light combiner is configured to transmit light of the first wavelength band and at least a portion of light of the second wavelength band and reflect at least a portion of light of the second or third wavelength band. The third light converging lens is arranged on one side, far away from the third light source, of the second light converging lens and is perpendicular to the light emitting direction of the third light source. The third light combiner is configured to reflect at least a portion of the light of the third wavelength band or the second wavelength band to excite at least one of the second light source or the third light source to emit light.

Drawings

In order to more clearly illustrate the technical solutions in the present disclosure, the drawings that are required to be used in some embodiments of the present disclosure will be briefly described below. However, the drawings in the following description are only drawings of some embodiments of the present disclosure, and other drawings may be obtained from these drawings by those of ordinary skill in the art. Furthermore, the drawings in the following description may be regarded as schematic diagrams, not limiting the actual size of the products, the actual flow of the methods, the actual timing of the signals, etc. according to the embodiments of the present disclosure.

FIG. 1 is a block diagram of a projection device according to some embodiments;

FIG. 2 is a partial block diagram of a projection device according to some embodiments;

FIG. 3 is an optical path diagram of a light source assembly, an optical engine, and a lens in a projection device according to some embodiments;

FIG. 4 is another optical path diagram of a light source assembly, an optical engine, and a lens in a projection device according to some embodiments;

FIG. 5 is a diagram of an arrangement of micro-mirror plates in a digital micromirror device according to some embodiments;

FIG. 6 is a diagram showing the position of a micro mirror plate wobble in the digital micromirror device of FIG. 5;

FIG. 7 is a schematic diagram of the operation of a micro mirror plate according to some embodiments;

FIG. 8 is yet another optical path diagram of a light source assembly, an optical engine, and a lens in a projection device according to some embodiments;

FIG. 9 is a block diagram of a light source assembly according to some embodiments;

FIG. 10 is a block diagram of another light source assembly according to some embodiments;

FIG. 11 is a block diagram of yet another light source assembly according to some embodiments;

FIG. 12 is a block diagram of yet another light source assembly according to some embodiments;

FIG. 13 is a block diagram of yet another light source assembly according to some embodiments;

FIG. 14 is a block diagram of yet another light source assembly according to some embodiments;

FIG. 15 is a block diagram of yet another light source assembly according to some embodiments;

FIG. 16 is a block diagram of yet another light source assembly according to some embodiments;

FIG. 17 is a block diagram of yet another light source assembly according to some embodiments;

fig. 18 is a block diagram of yet another light source assembly according to some embodiments.

Detailed Description

The following description of the embodiments of the present disclosure will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by one of ordinary skill in the art based on the embodiments provided by the present disclosure are within the scope of the present disclosure.

Throughout the specification and claims, unless the context requires otherwise, the word "comprise" and its other forms such as the third person referring to the singular form "comprise" and the present word "comprising" are to be construed as open, inclusive meaning, i.e. as "comprising, but not limited to. In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", "some examples", "and the like are intended to indicate that a particular feature, structure, material, or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The terms "first" and "second" are used below for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the embodiments of the present disclosure, unless otherwise indicated, the meaning of "a plurality" is two or more.

In describing some embodiments, the expression "connected" and its derivatives may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more elements are in direct physical or electrical contact with each other. The embodiments disclosed herein are not necessarily limited to the disclosure herein.

At least one of "A, B and C" has the same meaning as at least one of "A, B or C," both include the following combinations of A, B and C: a alone, B alone, C alone, a combination of a and B, a combination of a and C, a combination of B and C, and a combination of A, B and C.

"A and/or B" includes the following three combinations: only a, only B, and combinations of a and B.

As used herein, the term "if" is optionally interpreted to mean "when … …" or "at … …" or "in response to a determination" or "in response to detection" depending on the context. Similarly, the phrase "if determined … …" or "if detected [ stated condition or event ]" is optionally interpreted to mean "upon determining … …" or "in response to determining … …" or "upon detecting [ stated condition or event ]" or "in response to detecting [ stated condition or event ]" depending on the context.

The use of "adapted" or "configured to" herein is meant to be an open and inclusive language that does not exclude devices adapted or configured to perform additional tasks or steps.

In addition, the use of "based on" is intended to be open and inclusive in that a process, step, calculation, or other action "based on" one or more of the stated conditions or values may be based on additional conditions or beyond the stated values in practice.

As used herein, "about," "approximately" or "approximately" includes the stated values as well as average values within an acceptable deviation range of the particular values as determined by one of ordinary skill in the art in view of the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system).

As used herein, "parallel", "perpendicular", "equal" includes the stated case as well as the case that approximates the stated case, the range of which is within an acceptable deviation range as determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system). For example, "parallel" includes absolute parallel and approximately parallel, where the acceptable deviation range for approximately parallel may be, for example, a deviation within 5 °; "vertical" includes absolute vertical and near vertical, where the acceptable deviation range for near vertical may also be deviations within 5 °, for example. "equal" includes absolute equal and approximately equal, where the difference between the two, which may be equal, for example, is less than or equal to 5% of either of them within an acceptable deviation of approximately equal.

Fig. 1 is a block diagram of a projection device according to some embodiments.

Some embodiments of the present disclosure provide a projection device. As shown in fig. 1, the projection apparatus 1 includes a housing 40 (only a part of the housing 40 is shown in fig. 1), a light source assembly 10, a light machine 20, and a lens 30 which are assembled in the housing 40. The light source assembly 10 is configured to provide an illumination beam. The light engine 20 is configured to modulate an illumination beam provided by the light source assembly 10 with an image signal to obtain a projection beam. The lens 30 is configured to project a projection beam onto a screen or wall for imaging.

The light source assembly 10, the optical machine 20 and the lens 30 are sequentially connected along the light beam propagation direction, and are respectively wrapped by corresponding shells. The respective housings of the light source assembly 10, the light engine 20 and the lens 30 support the respective optical components and allow the respective optical components to meet certain sealing or airtight requirements. For example, the light source assembly 10 can improve the light attenuation problem of the light source assembly 10 by realizing airtight sealing through the corresponding shell.

One end of the optical machine 20 is connected to the lens 30, and the optical machine 20 and the lens 30 are disposed along the emission direction (refer to the N direction shown in fig. 2) of the projection light beam of the projection device 1. The light source module 10 is connected to the other end of the light machine 20. Fig. 2 is a partial block diagram of a projection device according to some embodiments. In this example, as shown in fig. 2, the light source assembly 10 and the light machine 20 are sequentially arranged along the M direction, and the light machine 20 and the lens 30 are sequentially arranged along the N direction, wherein the M direction and the N direction are perpendicular to each other. That is, the emission direction of the projection light beam of the projection device 1 is substantially perpendicular to the emission direction (refer to the M direction shown in fig. 2) of the illumination light beam of the projection device 1. The connection structure can adapt to the light path characteristics of the reflective light valve in the optical machine 20, and is beneficial to shortening the length of the light path in one dimension direction and the structural arrangement of the projection device 1. For example, when the light source module 10, the light machine 20, and the lens 30 are disposed in one dimension direction (for example, M direction perpendicular to the direction N), the length of the light path in the dimension direction is long, thereby adversely affecting the structural arrangement of the projection apparatus 1. The reflective light valve will be described later.

The illumination beam from the light source assembly 10 enters the light engine 20. Fig. 3 is an optical path diagram of a light source assembly, an optical engine, and a lens in a projection device according to some embodiments. Referring to fig. 3, the optical bench 20 includes: a light homogenizing part 210, a lens assembly 220, a digital micromirror device (Digital Micromirror Device, DMD) 240, and a prism assembly 250. The light homogenizing part 210 may receive the illumination beam provided from the light source assembly 10 and homogenize the illumination beam. The lens assembly 220 may amplify the illumination beam before converging and transmitting it to the prism assembly 250. The prism assembly 250 reflects the illumination beam to the digital micromirror device 240, modulates the illumination beam to obtain a projection beam, and reflects the modulated projection beam into the lens 30.

Fig. 4 is another optical path diagram of a light source assembly, an optical engine, and a lens in a projection device according to some embodiments.

In some embodiments, as shown in FIG. 4, the light engine 20 includes a converging lens 260 and a light pipe 230 in addition to the lens assembly 220, the digital micromirror device 240, and the prism assembly 250. The condensing lens 260 receives the illumination beam of the light source assembly 10 and condenses the illumination beam to the light guide 230. The light pipe 230 may receive and homogenize the illumination beam provided by the light source assembly 10. Furthermore, the exit of the light pipe 230 may be rectangular, thereby providing a shaping effect on the spot.

In the optical machine 20, the digital micromirror device 240 modulates the illumination beam provided by the light source assembly 10 with the image signal, namely: the projection beam is controlled to display different colors and brightness for different pixels of the image to be displayed to ultimately form an optical image, and thus the digital micromirror device 240 is also referred to as a light modulation device or light valve. The light modulation device (or light valve) may be classified as either a transmissive light modulation device (or light valve) or a reflective light modulation device (or light valve) depending on whether the light modulation device (or light valve) transmits or reflects the illumination beam.

For example, the digital micromirror device 240 shown in fig. 3 and 4 reflects an illumination beam, i.e., is a reflective light modulation device. The liquid crystal light valve transmits the illumination beam, so that the liquid crystal light valve is a transmission type light modulation device.

Further, the light engine 20 may be classified into a single-chip system, a two-chip system, or a three-chip system according to the number of light modulation devices (or light valves) used in the light engine 20. For example, only one piece of digital micromirror device 240 is used in the optical bench 20 shown in fig. 3 and 4, and thus the optical bench 20 may be referred to as a monolithic system. When a three-piece digital micromirror device 240 is used, then the light engine 20 may be referred to as a three-piece system.

When the light machine 20 is a three-chip system, the light source assembly 10 outputs three primary colors of light simultaneously to continuously emit white light.

It should be noted that, depending on the projection architecture, the light modulation device (or light valve) may include a variety of devices, such as liquid crystal on silicon (Liquid Crystal on Silicon, LCOS), liquid crystal display (Liquid Crystal Display, LCD), or DMD. Since in some embodiments of the present disclosure, the optical machine 20 shown in fig. 3 and 4 applies a digital light processing (Digital Light Processing, DLP) projection architecture, the light modulation device (or light valve) in some embodiments of the present disclosure is a Digital Micromirror Device (DMD) 240.

Fig. 5 is a diagram of an arrangement of micro mirror plates in a digital micromirror device according to some embodiments. Fig. 6 is a position diagram of a micro mirror plate swing in the digital micromirror device of fig. 5. Fig. 7 is a schematic diagram of the operation of a micro mirror plate according to some embodiments.

As shown in fig. 5, the digital micromirror device 240 includes thousands of micro mirror plates 2401 that can be individually driven to rotate, and the micro mirror plates 2401 are arranged in an array, and each micro mirror plate 2401 corresponds to one pixel in an image to be displayed. As shown in fig. 6, in the DLP projection architecture, each micro mirror 2401 corresponds to a digital switch, and can swing within a range of ±12° or ±17° under the action of an external force.

As shown in fig. 7, the light reflected by the micro mirror 2401 at the negative deflection angle is called OFF light, which is inactive light, and is normally incident on the housing 40 of the projection apparatus 1, the housing of the optical machine 20, or the light absorbing unit 400. The light reflected by the micro mirror 2401 at the positive deflection angle, which is called ON light, is an effective light beam irradiated by the illumination light beam received by the micro mirror 2401 ON the surface of the digital micromirror device 240 and incident ON the lens 30 through the positive deflection angle for projection imaging. The on state of the micro mirror 2401 is a state in which the micro mirror 2401 is in a state in which the micro mirror 2401 can be held, that is, a state in which the micro mirror 2401 is in a positive deflection angle, when the illumination light beam emitted from the light source module 10 is reflected by the micro mirror 2401 and can enter the lens 30. The off state of the micro mirror 2401 is a state in which the micro mirror 2401 is in a state in which the micro mirror 2401 can be held, that is, a state in which the micro mirror 2401 is in a negative deflection angle, when the illumination light beam emitted from the light source module 10 is reflected by the micro mirror 2401 and does not enter the lens 30.

For example, for the minute mirror 2401 having a deflection angle of ±12°, the state at +12° is the on state, the state at-12 ° is the off state, and for the deflection angle between-12 ° and +12°, the actual operation state of the minute mirror 2401 is only the on state and the off state, which are not actually used. In the case of the minute mirror 2401 having a deflection angle of ±17°, the state at +17° is the on state, and the state at-17 ° is the off state. The image signal is converted into digital codes of 0 and 1 after processing, and these digital codes can drive the micro mirror 2401 to oscillate.

In the display period of one frame image, part or all of the micro mirror plates 2401 are switched between the on state and the off state once, so that the gray scale of each pixel in one frame image is realized according to the time that the micro mirror plates 2401 are respectively in the on state and the off state. For example, when the pixel has 256 gradations of 0 to 255, the minute reflection mirror 2401 corresponding to the gradation 0 is in an off state for the entire display period of one frame image, the minute reflection mirror 2401 corresponding to the gradation 255 is in an on state for the entire display period of one frame image, and the minute reflection mirror 2401 corresponding to the gradation 127 is in an on state for half of the time and in an off state for the other half of the time in the display period of one frame image. Therefore, by controlling the state of each micro mirror 2401 in the digital micromirror device 240 and the maintenance time of each state in the display period of one frame image by the image signal, the brightness (gray scale) of the corresponding pixel of the micro mirror 2401 can be controlled, so that the illumination beam projected to the digital micromirror device 240 is modulated.

Referring to fig. 3 and 4, the light homogenizing part 210 and the lens assembly 220 at the front end of the digital micro mirror device 240 form an illumination light path, or the condensing lens 260, the light pipe 230, and the lens assembly 220 at the front end of the digital micro mirror device 240 form an illumination light path. The illumination beam from the light source assembly 10 passes through the illumination path to form a beam size and angle of incidence that meet the requirements of the dmd 240.

Fig. 8 is yet another optical path diagram of a light source assembly, an optical engine, and a lens in a projection device according to some embodiments. As shown in fig. 8, the lens 30 includes a plurality of lens combinations, and is generally divided into three sections of a front group, a middle group, and a rear group, or two sections of a front group and a rear group. The front group is a lens group near the light exit side of the projection apparatus 1 (i.e., the side of the lens 30 in the direction N away from the optical engine 20 in fig. 8), and the rear group is a lens group near the light exit side of the optical engine 20 (i.e., the side of the lens 30 in the direction N near the optical engine 20 in fig. 8). The lens 30 may be a zoom lens, or a fixed focus adjustable focus lens, or a fixed focus lens.

For convenience of description, some embodiments of the present disclosure mainly take the light source assembly 10 to output three primary colors of light in a time sequence, the projection apparatus 1 adopts a DLP projection architecture, and the light modulation device in the light engine 20 is a digital micromirror device 240 as an example.

The light source assembly 10 according to some embodiments of the present disclosure is described in detail below.

Fig. 9 is a block diagram of a light source assembly according to some embodiments.

In some embodiments, as shown in fig. 9, the light source assembly 10 includes four light sources, a light combining lens set 200, a first collimating lens set 41, and a second collimating lens set 42.

The four light sources are respectively: a first light source 11, a second light source 12, a third light source 13 and a fourth light source 14. The light emitting direction of the first light source 11 is parallel to the first direction X. The second light source 12 and the third light source 13 are sequentially arranged along the first direction X, and the light emitting directions of the second light source 12 and the third light source 13 are parallel to the second direction Y. The second light source 12 and the fourth light source 14 are sequentially arranged along the second direction Y, and the light emitting direction of the fourth light source 14 is opposite to the light emitting direction of the second light source 12. The outgoing light of the fourth light source 14 and the second light source 12 intersects with the outgoing light of the first light source 11. The first direction X is perpendicular to the second direction Y.

In some embodiments, the first light source 11 is configured to emit light of at least a first wavelength band, the second light source 12 is configured to emit light of at least a second wavelength band, the third light source 13 is configured to emit light of at least a third wavelength band, and the fourth light source 14 is configured to emit first excitation light to excite the second light source 12 to emit light of the second wavelength band.

The light of the first, second and third wavelength bands may correspond to different colors, respectively. For example, the first wavelength band corresponds to a wavelength band of blue light, the second wavelength Duan Duiying is a wavelength band of red light, and the third wavelength band corresponds to a wavelength band of green light; or the first wave band corresponds to a wave band of red light, the second wave band corresponds to a wave band of blue light, and the third wave band corresponds to a wave band of green light; or, the first band corresponds to a green band, the second band corresponds to a blue band, and the third band corresponds to a red band; alternatively, the first wavelength band corresponds to a wavelength band of green light, the second wavelength Duan Duiying is a wavelength band of red light, and the third wavelength band corresponds to a wavelength band of blue light.

The light combining lens set 200 includes a first light combining lens 21 and a second light combining lens 22. The first light combining lens 21 and the second light combining lens 22 are arranged in parallel, and the first light source 11, the first light combining lens 21 and the second light combining lens 22 are sequentially arranged along the first direction X. The first light combining mirror 21 is located at the intersection of the outgoing light of the first light source 11 and the second light source 12, and the first light combining mirror 21 is configured to transmit light of the first wavelength band and reflect light of the second wavelength band. The second light converging lens 22 is located at the intersection of the outgoing light of the first light converging lens 21 and the outgoing light of the third light source 13, and the second light converging lens 22 is configured to transmit light of the first and second wavelength bands and reflect light of the third wavelength band. Thus, the second light converging mirror 22 can emit light of the first wavelength band, the second wavelength band, and the third wavelength band.

In some embodiments, as shown in fig. 9, the first light converging lens 21 forms a first angle α (e.g., 45 ° ± 0.5 °) with the light emitting direction of the first light source 11. The second light converging lens 22 forms a second included angle beta with the light emitting direction of the third light source 13. The first angle alpha is equal to the second angle beta.

For example, the first angle α is equal to 45 ° and the second angle β is also equal to 45 °. In this case, the angles between the first light combining mirror 21 or the second light combining mirror 22 and the light emitting direction of any one of the light sources (for example, the first light source 11, the second light source 12, the third light source 13 or the fourth light source 14, etc.) may be 45 °, so that the first light combining mirror 21 or the second light combining mirror 22 may reflect light at an angle of 90 °, and thus the light of the first wavelength band, the light of the second wavelength band, and the light of the third wavelength band emitted by the second light combining mirror 22 may be parallel to each other.

In some embodiments, both the first combiner 21 and the second combiner 22 may employ dichroic mirrors.

The dichroic mirror is formed by coating a film on the surface of a transparent flat plate using a thin film interference principle (i.e., when light is incident on a thin film, the light is reflected at the upper and lower interfaces of the thin film, respectively, and the reflected light at the two interfaces interfere with each other to form new light).

Due to the difference in the incident angle of light, the thickness of the thin film, and the refractive index, the reflected light at the two interfaces may interfere constructively or destructively, and the incident angle of light incident to the dichroic mirror is approximately 45 ° in consideration of a certain error in the optical path of the incident light. Therefore, when the incident angle of light to the dichroic mirror is 35-55 ° (45 ° ± 10 °), the transmittance of the dichroic mirror to the light requiring reflection increase is more than 95%, and the transmittance to the light requiring reflection increase is less than 1%, so as to reflect the light of one wave band to the maximum extent and transmit the light of the other wave band, thereby realizing the separation function to the light of different wave bands.

In some embodiments, as shown in fig. 9, the first collimating lens group 41 is disposed between the second light source 12 and the first collimating lens 21. The first collimating lens group 41 is configured to collimate the light of the second wavelength band exiting from the second light source 12. The second collimating lens group 42 is arranged between the third light source 13 and the second light combining lens 22. The second collimating lens group 42 is configured to collimate the light of said third wavelength band exiting from the third light source 13.

The first collimating lens group 41 includes a convex lens, and a convex arc surface of the convex lens protrudes toward a direction approaching the first collimating lens 21. When the first collimating lens group 41 includes a plurality of convex lenses, the plurality of convex lenses may be sequentially arranged along the second direction Y, and optical axes of the plurality of convex lenses are collinear. Thus, the light emitted from the second light source 12 can be more accurately incident on the first light combining mirror 21.

In some embodiments, as shown in fig. 9, the first collimating lens group 41 includes two convex lenses, i.e., a first plano-convex lens 411 and a second plano-convex lens 412. Alternatively, the first collimating lens group 41 includes one hyperspherical convex lens and one plano-convex lens. Alternatively, the first collimating lens group 41 includes an hyperspherical convex lens and a concave-convex lens. The processing precision of the hyperspherical convex lens is high, and the light path error can be reduced. The meniscus reduces spherical aberration (Spherical Aberration) in the collimation of the fluorescence.

The structure and arrangement of the second collimating lens group 42 are the same as those of the first collimating lens group 41, and will not be described here.

Some embodiments of the present disclosure mainly take the first collimating lens group 41 and the second collimating lens group 42 respectively including two convex lenses as examples.

In some embodiments, as shown in fig. 9, the second light source 12 includes a first sub-light source 121 and a first phosphor layer 31 positioned on the light-emitting side of the first sub-light source 121. The third light source 13 includes a second sub-light source 131 and a second phosphor layer 32 positioned at the light emitting side of the second sub-light source 131.

For example, the first phosphor layer 31 is coated on the first sub-light source 121, and the first phosphor layer 31 is located between the first sub-light source 121 and the first collimating lens group 41. The third excitation light emitted from the first sub-light source 121 may be irradiated onto the first phosphor layer 31 to excite the first phosphor layer 31 to emit the fluorescence of the second wavelength band, so that the second light source 12 emits the light of the second wavelength band.

The second phosphor layer 32 is coated on the second sub-light sources 131, and the second phosphor layer 32 is located between the second sub-light sources 131 and the second collimating lens group 42. The fourth excitation light emitted from the second sub-light source 131 may be irradiated onto the second phosphor layer 32 to excite the second phosphor layer 32 to emit the fluorescence of the third wavelength band, so that the third light source 13 emits the light of the third wavelength band. The first and second sub-light sources 121 and 131 may each emit light of the first, second, or third wavelength bands.

In this case, the light of the first wavelength band emitted from the fourth light source 14 may pass through the first light converging lens 21 and be converged to the first phosphor layer 31 through the first collimating lens group 41, so as to excite the first phosphor layer 31 again to emit the fluorescent light of the second wavelength band. In this way, the number of times of excitation of the fluorescent powder can be increased, so that the excited fluorescence is multiplied, the luminous intensity of the excited fluorescence is increased, the brightness of the emergent light of the light source assembly 10 is improved, and the display effect of the projection device 1 is further improved.

In some embodiments, the first light source 11, the first sub-light source 121, the second sub-light source 131 and the fourth light source 14 can emit light with the same wavelength band. For example, the first light source 11, the first sub-light source 121, the second sub-light source 131 and the fourth light source 14 all emit light (such as blue light) of the first wavelength band.

For example, as shown in fig. 9, when the first light source 11, the first sub-light source 121, the second sub-light source 131, and the fourth light source 14 each emit blue light, the second light source 12 emits green light, and the third light source 13 emits red light, the first phosphor layer 31 is a green phosphor, and the second phosphor layer 32 is a red phosphor.

The blue light emitted from the first light source 11 sequentially transmits the first light combining lens 21 and the second light combining lens 22, and is emitted toward the light outlet of the light source assembly 10.

Blue light emitted from the first sub-light source 121 irradiates on the first phosphor layer 31 to excite the first phosphor layer 31 to emit green fluorescence. The blue light emitted from the fourth light source 14 passes through the first light converging lens 21 and is converged to the first fluorescent powder layer 31 through the first collimating lens group 41, so as to excite the first fluorescent powder layer 31 to emit green fluorescence. The green fluorescent light excited by the first sub-light source 121 and the fourth light source 14 is collimated by the first collimating lens group 41 and then enters the first light combining lens 21. The green fluorescent light is reflected to the second light converging lens 22 by the first light converging lens 21, then transmitted through the second light converging lens 22, and emitted towards the light outlet of the light source assembly 10.

The blue light emitted from the second sub-light source 131 irradiates on the second phosphor layer 32 to excite the second phosphor layer 32 to emit red fluorescence. The red fluorescent light excited by the second sub-light source 131 is collimated by the second collimating lens set 42, then enters the second light combining lens 22, and is reflected by the second light combining lens 22 to the light outlet of the light source assembly 10.

Since the excited fluorescent light is emitted in a lambertian body, a part of light in the fluorescent light needs to be collimated by the corresponding collimating lens group, so that the fluorescent light can be parallel incident to the corresponding collimating lens along the second direction Y.

In some embodiments of the present disclosure, the complexity of the optical path may be reduced by having the first light source 11, the first sub-light source 121, the second sub-light source 131, and the fourth light source 14 emit light of the same wavelength band. When blue light is used as excitation light (for example, each of the first sub-light source 121, the second sub-light source 131, and the fourth light source 14 emits blue light), excitation efficiency of the excitation light on the phosphor layer is high.

Fig. 10 is a block diagram of another light source assembly according to some embodiments.

In some embodiments, as shown in fig. 10, the light source assembly 10 further includes a fifth light source 15.

The fourth light source 14 and the fifth light source 15 are sequentially arranged along the first direction X, and the third light source 13 and the fifth light source 15 are sequentially arranged along the second direction Y. The light emitting direction of the fifth light source 15 is opposite to the light emitting direction of the third light source 13, and the fifth light source 15 is configured to emit the second excitation light to excite the third light source 13 to emit the light of the third wavelength band.

In this case, the light emitted from the fifth light source 15 may pass through the second light converging lens 22 and be converged to the second phosphor layer 32 by the second collimating lens set 42, so as to excite the second phosphor layer 32 to emit the fluorescent light of the third wavelength band again.

In some embodiments, the first light source, the first sub-light source 121, the second sub-light source 131, the fourth light source 14, and the fifth light source 15 may employ light emitting diodes or lasers.

In some embodiments, the first light source 11, the first sub-light source 121, the second sub-light source 131, the fourth light source 14, and the fifth light source 15 may emit light of the same wavelength band. For example, the first light source 11, the first sub-light source 121, the second sub-light source 131, the fourth light source 14, and the fifth light source 15 all emit light (such as blue light) in the first wavelength band.

In some examples, as shown in fig. 10, in the case where the first light source 11, the first sub-light source 121, the second sub-light source 131, the fourth light source 14, and the fifth light source 15 all emit blue light, the first phosphor layer 31 may be green phosphor, and the second phosphor layer 32 may be red phosphor.

Fig. 11 is a block diagram of yet another light source assembly of some embodiments.

In some embodiments, as shown in fig. 10 and 11, there is no overlapping band between the second band and the third band. That is, the fluorescence emitted from the first sub-light source 121 excited by the first phosphor layer 31 and the fluorescence emitted from the second sub-light source 131 excited by the second phosphor layer 32 have different colors. In this way, it is easy to distinguish the channels of the different colors of light.

The following description will take, as an example, the first light source 11, the first sub-light source 121, the second sub-light source 131, the fourth light source 14, and the fifth light source 15 all emit blue light.

As shown in fig. 10, in the case where the second light source 12 emits green light and the third light source 13 emits red light, the first phosphor layer 31 is green phosphor and the second phosphor layer 32 is red phosphor. In this case, the first light combining mirror 21 may transmit blue light, reflect green light, and the second light combining mirror 22 may transmit blue light and green light, reflect red light.

At this time, the first wavelength band corresponding to the blue light emitted from the first light source 11, the first sub-light source 121, the second sub-light source 131, the fourth light source 14 and the fifth light source 15 is 430nm to 470nm, the second wavelength band corresponding to the green light emitted from the second light source 12 is 500nm to 570nm, and the third wavelength band corresponding to the red light emitted from the third light source 13 is 600nm to 680nm.

The range of each wave band corresponds to the wave band of the light with the corresponding color emitted by the light emitting diode or the laser. In general, in a light emitting diode or a laser, the wavelength range of blue light is 430nm to 470nm, the wavelength range of green light is 500nm to 570nm, and the wavelength range of red light is 600nm to 680nm.

As shown in fig. 10, the blue light emitted from the first light source 11 sequentially transmits the first light converging lens 21 and the second light converging lens 22, and is emitted toward the light outlet of the light source assembly 10.

Blue light emitted from the first sub-light source 121 is irradiated onto the first phosphor layer 31 (green phosphor layer) to excite the first phosphor layer 31 to emit green fluorescence. The blue light emitted from the fourth light source 14 passes through the first light converging lens 21 and is converged to the first fluorescent powder layer 31 through the first collimating lens group 41, so as to excite the first fluorescent powder layer 31 to emit green fluorescence. The green fluorescent light excited by the first sub-light source 121 and the fourth light source 14 is collimated by the first collimating lens group 41 and then enters the first light combining lens 21. The green fluorescent light is reflected to the second light converging lens 22 by the first light converging lens 21, then transmitted through the second light converging lens 22, and emitted towards the light outlet of the light source assembly 10.

The blue light emitted from the second sub-light source 131 is irradiated onto the second phosphor layer 32 (red phosphor layer) to excite the second phosphor layer 32 to emit red fluorescence. The blue light emitted from the fifth light source 15 passes through the second light combining lens 22 and is converged to the second fluorescent powder layer 32 by the second collimating lens set 42, so as to excite the second fluorescent powder layer 32 to emit red fluorescent light. The red fluorescent light excited by the second sub-light source 131 and the fifth light source 15 is collimated by the second collimating lens set 42, then enters the second light combining lens 22, and is reflected by the second light combining lens 22 to the light outlet of the light source assembly 10.

The following description will be given by taking a blue light having a wavelength of 430nm to 470nm, a green light having a wavelength of 500nm to 570nm, and a red light having a wavelength of 600nm to 680nm as an example.

As shown in fig. 11, in the case where the second light source 12 emits red light and the third light source 13 emits green light, the first phosphor layer 31 is red phosphor and the second phosphor layer 32 is green phosphor.

In this case, the first light combining mirror 21 may transmit blue light, reflect red light, and the second light combining mirror 22 may transmit blue light and red light, reflect green light.

As shown in fig. 11, the blue light emitted from the first light source 11 sequentially transmits the first light converging lens 21 and the second light converging lens 22, and is emitted toward the light outlet of the light source assembly 10.

Blue light emitted from the first sub-light source 121 is irradiated onto the first phosphor layer 31 (red phosphor layer) to excite the first phosphor layer 31 to emit red fluorescence. The blue light emitted from the fourth light source 14 passes through the first light converging lens 21 and is converged to the first fluorescent powder layer 31 through the first collimating lens group 41, so as to excite the first fluorescent powder layer 31 to emit red fluorescent light. The red fluorescent light excited by the first sub-light source 121 and the fourth light source 14 is collimated by the first collimating lens group 41 and then enters the first light combining lens 21. The red fluorescent light is reflected to the second light converging lens 22 by the first light converging lens 21, then transmitted through the second light converging lens 22, and emitted towards the light outlet of the light source assembly 10.

The blue light emitted from the second sub-light source 131 is irradiated onto the second phosphor layer 32 (green phosphor layer) to excite the second phosphor layer 32 to emit green fluorescence. The blue light emitted from the fifth light source 15 passes through the second light combining lens 22 and is converged to the second fluorescent powder layer 32 by the second collimating lens set 42, so as to excite the second fluorescent powder layer 32 to emit green fluorescent light. The green fluorescent light excited by the second sub-light source 131 and the fifth light source 15 is collimated by the second collimating lens set 42, then enters the second light combining lens 22, and is reflected by the second light combining lens 22 to the light outlet of the light source assembly 10.

In some embodiments of the present disclosure, by providing the fourth light source 14 and the fifth light source 15, the first phosphor layer 31 and the second phosphor layer 32 may be excited twice to increase the number of times the first phosphor layer 31 and the second phosphor layer 32 are excited, thereby increasing the brightness of red light and green light among the three primary colors of light and increasing the display effect of the projection apparatus 1.

Fig. 12 is a block diagram of yet another light source assembly according to some embodiments, and fig. 13 is a block diagram of yet another light source assembly according to some embodiments. Fig. 14 is a block diagram of yet another light source assembly according to some embodiments, and fig. 15 is a block diagram of yet another light source assembly according to some embodiments.

In some embodiments, as shown in fig. 12, 13 and 15, the second band of wavelengths has an overlapping band with the third band of wavelengths. That is, the fluorescence emitted from the first sub-light source 121 to excite the first phosphor layer 31 or the fluorescence emitted from the second sub-light source 131 to excite the second phosphor layer 32 may include a plurality of wavelength bands of monochromatic light. For example, the second or third wavelength band is a wavelength band of yellow light, and the yellow light has a wavelength band of red light and a wavelength band of green light.

In this case, in some embodiments, the second light combiner 22 is configured to transmit light of the first wavelength band, and at least a portion of light of the second wavelength band, and reflect at least a portion of light of the second or third wavelength band. In this way, the monochromatic light with a corresponding wavelength band can be separated from the fluorescence emitted by the first sub-light source 121 exciting the first fluorescent powder layer 31 or the fluorescence emitted by the second sub-light source 131 exciting the second fluorescent powder layer 32 through the light combining lens set 200, so as to meet the requirement of projection display.

In some embodiments, as shown in fig. 12 and 13, either one of the second light source 12 and the third light source 13 emits yellow light, and the other emits green light. The fluorescent powder layer corresponding to the light source emitting yellow light is a yellow fluorescent powder layer, and the fluorescent powder layer corresponding to the light source emitting green light is a green fluorescent powder layer.

As shown in fig. 12, in the case where the second light source 12 emits green light and the third light source 13 emits yellow light, the first phosphor layer 31 is a green phosphor layer and the second phosphor layer 32 is a yellow phosphor layer. In this case, the first light combining mirror 21 may transmit blue light, reflect green light, and the second light combining mirror 22 may transmit blue light and green light, reflect red light.

At this time, the third wavelength band corresponding to the yellow light emitted from the third light source 13 is 500nm to 680nm.

The wavelength band of the yellow light here corresponds to the wavelength band of the yellow light emitted by the light-emitting diode or the laser. As shown in fig. 12, the light path of the blue light emitted from the first light source 11, the light path of the green fluorescence emitted from the first sub-light source 121 and the fourth light source 14 exciting the first phosphor layer 31 (green phosphor layer) are the same as described above, and the description thereof is omitted.

Blue light emitted from the second sub-light source 131 is irradiated onto the second phosphor layer 32 (yellow phosphor layer) to excite the second phosphor layer 32 to emit yellow fluorescence. The blue light emitted from the fifth light source 15 passes through the second light combining lens 22 and is converged to the second fluorescent powder layer 32 by the second collimating lens group 42, so as to excite the second fluorescent powder layer 32 to emit yellow fluorescent light.

Since the wavelength band (500 nm to 680 nm) of yellow fluorescence includes the wavelength band (600 nm to 680 nm) of red light and the wavelength band (500 nm to 570 nm) of green light, after the yellow fluorescence excited by the second sub-light source 131 and the fifth light source 15 is incident on the second light combining mirror 22, a first portion (red light) of the yellow fluorescence is reflected to the light outlet of the light source module 10 through the second light combining mirror 22. A second portion of the yellow fluorescent light (green light) may be transmitted through the second light combining mirror 22.

In some embodiments, where the third light source 13 emits yellow light, the second light source 12 may also emit red light. In this case, the second light combining lens set 22 transmits blue light and red light, and reflects green light.

At this time, the light paths of the first light source 11, the second light source 12, the third light source 13, the fourth light source 14 and the fifth light source 15 are the same as those described above, and the description thereof is omitted.

In some embodiments of the present disclosure, since the excitation efficiency of the yellow phosphor layer is greater than that of the red phosphor layer, the brightness of red light in the tri-primary light may be improved by using the yellow phosphor layer instead of the red phosphor layer and using the second light combiner 22 to separate red light from the yellow fluorescence for reflection, thereby improving the display effect of the projection apparatus 1.

In some embodiments, in the case where the second light combining lens 22 is a dichroic mirror, by adjusting the coating film on the second light combining lens 22, red light in a specific wavelength range can be extracted from the excited yellow fluorescent light, so as to enhance the color gamut of the red light and improve the display effect of the projection apparatus 1.

In some embodiments, as shown in fig. 13, the light combining lens set 200 further includes a third light combining lens 23, the third light combining lens 23 being configured to transmit light of the first wavelength band, reflect at least a portion of the light of the third wavelength band or the second wavelength band, and to re-excite at least one of the second light source 12 or the third light source 13. The third light combiner 23 is arranged between the fifth light source 15 and the second light combiner 22. The third light combining mirror 23 is arranged perpendicular to the light exit direction of the fifth light source 15. For example, the third dichroic mirror 23 may be a dichroic mirror.

In some embodiments, as shown in fig. 13, in the case where the second light source 12 emits yellow light and the third light source 13 emits green light, the first phosphor layer 31 is a yellow phosphor layer and the second phosphor layer 32 is a green phosphor layer. In this case, the first light combining mirror 21 may transmit blue light, reflect yellow light, and the second light combining mirror 22 may transmit blue light and red light, reflect green light. The third light combining mirror 23 may transmit blue light and reflect green light.

At this time, as shown in fig. 13, the light path of the blue light emitted from the first light source 11, the light path of the green fluorescence emitted from the second phosphor layer 32 (green phosphor layer) excited by the second sub-light source 131 and the fifth light source 15 are the same as those described above, and the description thereof is omitted.

Blue light emitted from the first sub-light source 121 is irradiated onto the first phosphor layer 31 (yellow phosphor layer) to excite the first phosphor layer 31 to emit yellow fluorescence. The blue light emitted from the fourth light source 14 passes through the first light converging lens 21 and is converged to the first fluorescent powder layer 31 through the first collimating lens group 41, so as to excite the first fluorescent powder layer 31 to emit yellow fluorescent light. The yellow fluorescent light excited by the first sub-light source 121 and the fourth light source 14 is collimated by the first collimating lens group 41, then enters the first light combining lens 21 and is reflected by the first light combining lens 21 to the second light combining lens 22.

Since the wavelength band (500 nm to 680 nm) of the yellow fluorescent light includes the wavelength band (600 nm to 680 nm) of the red light and the wavelength band (500 nm to 570 nm) of the green light, after the yellow fluorescent light excited by the first sub-light source 121 and the fourth light source 14 is incident on the second light combining mirror 22, a first portion (red light) of the yellow fluorescent light is transmitted through the second light combining mirror 22 and is emitted toward the light emitting port of the light source module 10, thereby separating the red light from the yellow fluorescent light and emitting the three primary colors of light from the light source module 10.

In general, the brightness of the red light is lower than the brightness of the blue light and the green light, and therefore, in order to ensure the color uniformity of the light emitted from the light source assembly 10 in the projection apparatus 1, the brightness of the red light in the trichromatic light is improved to satisfy the brightness ratio in the trichromatic light, and the second portion (green light) in the yellow fluorescence may be reflected to the third light combining lens 23 through the second light combining lens 22.

The green light incident on the third light combining mirror 23 is reflected by the third light combining mirror 23 back to the second light combining mirror 22 and is reflected by the second light combining mirror 22 back to the first light combining mirror 21. The green light reflected by the second light combining lens 22 is reflected by the first light combining lens 21 back to the first collimating lens set 41, and is converged to the first fluorescent powder layer 31 by the first collimating lens set 41, so that the first fluorescent powder layer 31 is excited again to emit yellow fluorescent light, and the above steps are repeated. The red light in the re-excited yellow fluorescent light is emitted to the light outlet of the light source assembly 10 along the light path, so that the brightness of the red light emitted by the light source assembly 10 is increased.

Thus, by repeatedly using the reflected green light, the yellow phosphor layer can be excited a plurality of times, and the luminous intensity and fluorescence efficiency of the yellow fluorescence are improved, thereby improving the brightness of the red light in the three primary colors of light and improving the display effect of the projection device 1. Further, by providing the third light combining mirror 23, the brightness of the red light can be increased without adding an additional red light source, and the color uniformity of the light emitted from the light source assembly 10 can be improved.

In some embodiments, as shown in fig. 14, where the second light source 12 emits yellow light, the third light source may emit red light. In this case, the second light combining lens group 22 may transmit blue light and green light, reflecting red light. The third light combining mirror 23 may transmit blue light and reflect red light.

The optical paths of the first light source 11, the second light source 12, the third light source 13, the fourth light source 14 and the fifth light source 15 are the same as those described above, and the description thereof will be omitted.

In some embodiments, as shown in fig. 15, in the case where the second light source 12 and the third light source 13 both emit yellow light, the first phosphor layer 31 and the second phosphor layer 32 are both yellow phosphor layers. In this case, the first light combining mirror 21 may transmit blue light, reflect yellow light, and the second light combining mirror 22 may transmit blue light and red light, reflect green light. The third light combining mirror 23 may transmit blue light, reflect green light and red light.

As shown in fig. 15, the light path of the blue light emitted from the first light source 11, the light path of the yellow fluorescence emitted from the first sub-light source 121 and the fourth light source 14 exciting the first phosphor layer 31 (yellow phosphor layer) are the same as described above, and the description thereof is omitted.

Blue light emitted from the second sub-light source 131 is irradiated onto the second phosphor layer 32 (yellow phosphor layer) to excite the second phosphor layer 32 to emit yellow fluorescence. The blue light emitted from the fifth light source 15 sequentially passes through the third light combining lens 23 and the second light combining lens 22, and is converged to the second fluorescent powder layer 32 through the second collimating lens group 42, so as to excite the second fluorescent powder layer 32 to emit yellow fluorescent light. The yellow fluorescent light excited by the second sub-light source 131 and the fifth light source 15 is collimated by the second collimating lens group 42 and then enters the second light combining lens 22.

Since the wavelength band (500 nm to 680 nm) of yellow fluorescence includes the wavelength band (600 nm to 680 nm) of red light and the wavelength band (500 nm to 570 nm) of green light, after the yellow fluorescence excited by the second sub-light source 131 and the fifth light source 15 is incident on the second light combining mirror 22, a first portion (red light) of the yellow fluorescence is transmitted through the second light combining mirror 22 and is incident on the third light combining mirror 23. A second portion of the yellow fluorescent light (green light) is reflected by the second light combining mirror 22 to the light outlet of the light source assembly 10.

The red light incident on the third light combining lens 23 is reflected by the third light combining lens 23 back to the second light combining lens 22, and is incident on the second collimating lens group 42 through the second light combining lens 22. The second collimating lens group 42 converges the red light transmitted through the second collimating lens 22 to the second phosphor layer 32, so as to excite the second phosphor layer 32 to emit yellow fluorescent light again, and the above steps are repeated. Thus, by exciting the yellow phosphor layer a plurality of times with the reflected red light, the luminous intensity of yellow fluorescence can be improved, thereby improving the fluorescence efficiency.

In some embodiments, in the case where the second light source 12 and the third light source 13 both emit yellow light, the second light combining lens set 22 may transmit blue light and green light, and reflect red light. The third light combining mirror 23 may transmit blue light, reflect red light, and green light.

In some embodiments of the present disclosure, by recycling the green light and the red light in the yellow fluorescence, the fluorescence efficiency can be improved, thereby improving the brightness of the red light and the green light in the trichromatic light and improving the display effect of the projection apparatus 1.

Fig. 16 is a block diagram of yet another light source assembly according to some embodiments. Fig. 17 is a block diagram of yet another light source assembly according to some embodiments. Fig. 18 is a block diagram of yet another light source assembly according to some embodiments.

In some embodiments, as shown in fig. 16 to 18, in the case where the second and third wavelength bands have overlapping wavelength bands, the light source assembly 10 may not include the fifth light source 15. At this time, the third light-combining lens group 23 can excite the phosphor layer (at least one of the first phosphor layer 31 and the second phosphor layer 32) again or repeatedly by at least one of the green light or the red light in the yellow fluorescence to emit the corresponding fluorescence only by reflecting the incident light.

The light path of the light source assembly 10 as shown in fig. 16 to 18 can be referred to above, and will not be described here again.

The foregoing is merely a specific embodiment of the disclosure, but the protection scope of the disclosure is not limited thereto, and any person skilled in the art who is skilled in the art will recognize that changes or substitutions are within the technical scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

A projection device comprising a light source assembly, the light source assembly comprising:

a plurality of light sources, the plurality of light sources comprising:

a first light source configured to emit at least light of a first wavelength band, the light-emitting direction of the first light source being parallel to a first direction;

a second light source configured to emit at least light of a second wavelength band;

a third light source configured to emit at least light of a third wavelength band, light emitting directions of the second light source and the third light source being parallel to a second direction, the second direction being perpendicular to the first direction; and

a fourth light source configured to emit first excitation light to excite the second light source to emit light of the second wavelength band, the light emitting direction of the fourth light source being opposite to the light emitting direction of the second light source; and

A combiner set, the combiner set comprising:

a first light combining lens disposed at an intersection of the outgoing light of the first light source and the second light source, the first light combining lens configured to transmit the light of the first wavelength band and reflect the light of the second wavelength band;

a second light converging lens disposed at an intersection of the outgoing light of the first light converging lens and the outgoing light of the third light source, and configured to transmit light of the first wavelength band and at least a portion of light of the second wavelength band, and reflect at least a portion of light of the second wavelength band or the third wavelength band; and

and a third light converging lens disposed at a side of the second light converging lens away from the third light source and perpendicular to a light emitting direction of the third light source, the third light converging lens configured to reflect at least a portion of the light of the third wavelength band or the second wavelength band to excite at least one of the second light source or the third light source.
The projection device of claim 1, wherein,

the second light source comprises a first sub-light source and a first fluorescent powder layer, the first fluorescent powder layer is arranged on the light emitting side of the first sub-light source, and the first sub-light source is configured to emit third excitation light so as to excite the first fluorescent powder layer to emit light of the second wave band;

The third light source comprises a second sub-light source and a second fluorescent powder layer, the second fluorescent powder layer is arranged on the light emitting side of the second sub-light source, and the second sub-light source is configured to emit fourth excitation light so as to excite the second fluorescent powder layer to emit light of the third wave band;

the second band of wavelengths has an overlapping band of wavelengths with the third band of wavelengths.
The projection device of claim 2, wherein the first and second sub-light sources each emit blue light.
The projection device of claim 2, wherein,

the first light source and the fourth light source emit blue light;

the second light source emits yellow light, and the third light source emits green light;

the first light combining mirror is configured to transmit blue light and reflect yellow light;

the second light combining mirror is configured to transmit blue light and red light and reflect green light;

the third light combining mirror is configured to reflect green light.
The projection device of claim 4, wherein the first phosphor layer is a yellow phosphor layer and the second phosphor layer is a green phosphor layer.
The projection device of claim 2, wherein,

The first light source and the fourth light source emit blue light;

the second light source emits yellow light, and the third light source emits red light;

the first light combining mirror is configured to transmit blue light and reflect yellow light;

the second light combining mirror is configured to transmit blue light and green light and reflect red light;

the third light combining mirror is configured to reflect red light.
The projection device of claim 6, wherein the first phosphor layer is a yellow phosphor layer and the second phosphor layer is a red phosphor layer.
The projection device of claim 2, wherein,

the first light source and the fourth light source emit blue light;

the second light and the third light source emit yellow light;

the first light combining mirror is configured to transmit blue light and reflect yellow light;

the second light combining mirror is configured to transmit blue light and red light and reflect green light;

the third light combining mirror is configured to reflect green light as well as red light.
The projection device of claim 2, wherein,

the first light source and the fourth light source emit blue light;

the second light source and the third light source emit yellow light;

The first light combining mirror is configured to transmit blue light and reflect yellow light;

the second light combining mirror is configured to transmit blue light and green light and reflect red light;

the third light combining mirror is configured to reflect red light and green light.
The projection device of claim 8 or 9, wherein the first phosphor layer is a yellow phosphor layer and the second phosphor layer is a yellow phosphor layer.
The projection device of claim 2, wherein,

the first light source and the fourth light source emit blue light;

the second light source emits green light, and the third light source emits yellow light;

the first light combining mirror is configured to transmit blue light and reflect green light;

the second light combining mirror is configured to transmit blue light and green light and reflect red light;

the third light combining mirror is configured to reflect green light.
The projection device of claim 11, wherein the first phosphor layer is a green phosphor layer and the second phosphor layer is a yellow phosphor layer.
The projection device of claim 2, wherein,

the first light source and the fourth light source emit blue light;

The second light source emits red light, and the third light source emits yellow light;

the first light combining mirror is configured to transmit blue light and reflect red light;

the second light combining mirror is configured to transmit blue light and red light and reflect green light;

the third light combining mirror is configured to reflect red light.
The projection device of claim 13, wherein the first phosphor layer is a red phosphor layer and the second phosphor layer is a yellow phosphor layer.
The projection device of any one of claims 1 to 14, wherein,

the light source assembly further comprises a fifth light source, the light emergent direction of the fifth light source is opposite to the light emergent direction of the third light source, and the fifth light source is configured to emit second excitation light so as to excite the third light source to emit light of the third wave band;

the second light combining mirror and the third light combining mirror are further configured to transmit the second excitation light.
The projection device of claim 15, wherein the fifth light source emits blue light.
The projection apparatus according to claim 15, wherein the second light source and the third light source are arranged in sequence along the first direction, and the fourth light source and the fifth light source are arranged in sequence along the first direction;

The second light source and the fourth light source are sequentially arranged along the second direction, and the third light source and the fifth light source are sequentially arranged along the second direction.
The projection device of any one of claims 1 to 17, wherein the light source assembly further comprises:

a first collimating lens set disposed between the second light source and the first light converging lens, the first collimating lens set configured to collimate the light of the second wavelength band emitted from the second light source; and

the second collimating lens group is arranged between the third light source and the second light converging lens and is configured to collimate the light of the third wave band emitted by the third light source.
The projection device of any one of claims 1 to 18, wherein the plurality of light sources are light emitting diodes or lasers.
The projection device of any one of claims 1 to 19, further comprising:

a light engine configured to modulate a light beam incident to the light engine according to an image signal; and

a lens configured to project a light beam incident to the lens to form a projection screen.