Projection system

Abstract

The application provides a projection system. The projection system comprises: a light source; a first dissipation element located on the light exit side of the light source; a light guiding element for receiving light emitted by the light source and passing through the first dissipation element along a first light path, and making the light pass through the first dissipation element again along a second light path; a second dissipation element for receiving light passing through the first dissipation element again along the second light path, wherein the second dissipation element comprises at least two phase modulation regions, and the polarization state of the light passing through the at least two phase modulation regions is different; and a light homogenizing element located on the light exit side of the second dissipation element, wherein the light beam emitted by the second dissipation element enters the light homogenizing element. The application solves the problem that the existing projection system has poor improvement effect on speckle phenomenon.

Description

Technical Field

[0001] This invention relates to the field of optical equipment technology, and more specifically, to a projection system. Background Technology

[0002] With the continuous development and advancement of optical imaging equipment, imaging devices with different display effects are gradually gaining popularity. For example, in projection systems, to ensure color display, three-color lasers are typically used as the light source. However, because the three different wavelengths of laser beams interfere with each other during projection after refraction and reflection by optical elements, speckle phenomena occur. This speckle phenomenon leads to a decrease in image quality, resulting in a hazy, blurred image and reduced resolution, thus degrading the user experience.

[0003] Currently, the common approach is to add a diffuser sheet to the projection system as a speckle-reducing element to alleviate speckle. However, this approach undoubtedly increases the overall size of the projection, and the speckle reduction effect is also poor when using only one diffuser sheet.

[0004] In other words, existing projection systems suffer from poor speckle reduction. Summary of the Invention

[0005] The main objective of this invention is to provide a projection system that solves the problem of poor speckle effect in existing projection systems.

[0006] To achieve the above objectives, the present invention provides a projection system comprising: a light source; a first dissipation element located on the light-emitting side of the light source; a light guiding element for receiving light emitted from the light source that passes through the first dissipation element along a first optical path, and causing it to pass through the first dissipation element again along a second optical path; a second dissipation element for receiving light that passes through the first dissipation element again along the second optical path, the second dissipation element comprising at least two phase modulation regions, wherein the polarization state of the light passing through the at least two phase modulation regions is different; and a light homogenizing element located on the light-emitting side of the second dissipation element, wherein the light beam emitted from the second dissipation element enters the light homogenizing element.

[0007] Furthermore, the light spot on the first dissipation element along the first optical path may or may not overlap with the light spot on the first dissipation element along the second optical path.

[0008] Furthermore, the light guiding element includes one or more light guiding sheets. When there are multiple light guiding sheets, the multiple light guiding sheets include a first light guiding sheet and a second light guiding sheet. The first light guiding sheet and the second light guiding sheet are arranged at an angle. The first light guiding sheet is used to receive light passing through the first dissipation element along the first light path and reflect the light to the second light guiding sheet. The second light guiding sheet is used to reflect the light along the second light path.

[0009] Furthermore, the light source includes a first light source emitting light in the first wavelength band, a second light source emitting light in the second wavelength band, and a third light source emitting light in the third wavelength band. The light divergence angle of at least one of the first and second light sources is smaller than that of the third light source. The first dissipation element includes a first dissipation region, a second dissipation region, and a third dissipation region. The diffusion angle of the dissipation region corresponding to one of the first and second light sources is larger than that of the dissipation region corresponding to the third light source.

[0010] Furthermore, the first dissipation element is oscillating or rotating, and the first dissipation element is divided into multiple dissipation zones along the circumference. The multiple dissipation zones are all fan-shaped, and at least two of the multiple dissipation zones have different diffusion angles for different colors of light.

[0011] Furthermore, the second dissipation element includes a plurality of first phase modulation regions and a plurality of second phase modulation regions. The first phase modulation regions and the second phase modulation regions are alternately arranged in a first direction and a second direction of the second dissipation element. The first direction is perpendicular to the second direction, and the polarization direction of the light passing through the first phase modulation region is perpendicular to the polarization direction of the light passing through the second phase modulation region.

[0012] Furthermore, the light-monopolating element is a compound eye element, and at least one side surface of the compound eye element has a microlens array, the microlens array including multiple microlenses, and the size of the phase modulation region is less than or equal to the size of the microlenses.

[0013] Furthermore, the second dissipation element includes a first phase modulation surface and a second phase modulation surface disposed opposite to each other. Both the first phase modulation surface and the second phase modulation surface include multiple phase modulation layers. The multiple phase modulation layers of the first phase modulation surface are arranged at intervals along a first direction and extend along a second direction. The multiple phase modulation layers of the second phase modulation surface are arranged at intervals along the second direction and extend along the first direction. The first direction is perpendicular to the second direction.

[0014] Furthermore, the projection system also includes a third reflector, which is used to obliquely direct the light emitted from the light source onto the first dissipation element.

[0015] Furthermore, the projection system also includes a shaping lens group, which is located between the first and second diffusing elements or on the side of the light-diffusing element away from the second diffusing element. When the shaping lens group is located on the side of the light-diffusing element away from the second diffusing element, the projection system also includes a light bar, which is located on the light-emitting side of the shaping lens group.

[0016] Furthermore, the projection system also includes a compound eye structure, which is located in the first light path from which the light source emerges.

[0017] Furthermore, the projection system also includes a first supplementary light source and a light combining device. The light combining device is located between the first dissipation element and the second dissipation element. The first supplementary light emitted from the first supplementary light source is incident on the second dissipation element through the light combining device. Alternatively, the projection system also includes a second supplementary light source, which includes a first supplementary part and a second supplementary part. The second supplementary light emitted from the first supplementary part is reflected by a light guiding element to the second supplementary part and excites the second supplementary part to form fluorescence. The fluorescence is transmitted through the light guiding element and incident on the first dissipation element along the second light path.

[0018] Furthermore, the light source includes a first light source, a second light source, and a third light source. The projection system outputs multiple frames of images, each frame of image including at least a first timing sequence, a second timing sequence, and a third timing sequence. The first timing sequence is that light emitted from the first light source is incident on the homogenizing element; the second timing sequence is that light emitted from the second light source is incident on the homogenizing element, and / or fluorescence or a first supplementary light is incident on the homogenizing element; the third timing sequence is that light emitted from the third light source is incident on the homogenizing element, and / or fluorescence or the first supplementary light is incident on the homogenizing element.

[0019] Furthermore, each frame of the image also includes a fourth time sequence and a fifth time sequence. The fourth time sequence is that the first light source and the second light source emit light simultaneously, and the emitted light is incident on the homogenizing element, and / or fluorescence or the first supplementary light is incident on the homogenizing element; the fifth time sequence is that the second light source and the third light source emit light simultaneously, and the emitted light is incident on the homogenizing element, and / or fluorescence or the first supplementary light is incident on the homogenizing element.

[0020] Furthermore, the projection system also includes a first supplementary light source and a light combining device. The light combining device is located between the first dissipation element and the second dissipation element. The first supplementary light emitted from the first supplementary light source is incident on the second dissipation element through the light combining device. The light combining device is a dichroic mirror, or a structure with a film layer in the middle region, or a structure with a hollow middle region.

[0021] According to the technical solution of the present invention, the projection system includes a light source, a first dissipation element, a light guiding element, a second dissipation element, and a light homogenizing element. The first dissipation element is located on the light-emitting side of the light source. The light guiding element is used to receive the light emitted from the light source that passes through the first dissipation element along the first light path, and to make it pass through the first dissipation element again along the second light path. The second dissipation element is used to receive the light that passes through the first dissipation element again along the second light path. The second dissipation element includes at least two phase modulation regions, and the polarization state of the light passing through the at least two phase modulation regions is different. The light homogenizing element is located on the light-emitting side of the second dissipation element, and the light beam emitted from the second dissipation element enters the light homogenizing element.

[0022] By setting a first dissipation element and a light guide on the light-emitting side of the light source, the light emitted from the light source along the first optical path is first dissipated by the first dissipation element, then deflected by the light guide and passes through the first dissipation element a second time along the second optical path. This allows the light to pass through the first dissipation element twice, achieving a double dissipation effect. This helps to ensure the dissipation effect while compressing the optical path volume, ensuring miniaturization. Simultaneously, a second dissipation element is set, which includes at least two phase modulation regions. The polarization state of the light passing through these two phase modulation regions is different, allowing the light, after being dissipated twice by the first dissipation element, to undergo further phase dissipation by the second dissipation element, further disrupting spatial coherence and greatly increasing the speckle elimination effect, ensuring high imaging quality of the projection system. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 A schematic diagram of the optical path of the projection system according to Embodiment 1 of the present invention is shown;

[0025] Figure 2 It shows Figure 1 A schematic diagram of the two sides of the second dissipation element of the projection system in the image;

[0026] Figure 3 It shows Figure 1 A schematic diagram of the polarization state of the second dissipation element in the projection system;

[0027] Figure 4 It shows Figure 1 A schematic diagram of the partitioning of the first dissipation element of the projection system in the image;

[0028] Figure 5 A schematic diagram of the optical path of the projection system according to Embodiment 2 of the present invention is shown;

[0029] Figure 6 A schematic diagram of the optical path of the projection system according to Embodiment 3 of the present invention is shown;

[0030] Figure 7 A schematic diagram of the optical path of the projection system according to Embodiment 4 of the present invention is shown;

[0031] Figure 8 A schematic diagram of the optical path of the projection system according to Embodiment 5 of the present invention is shown;

[0032] Figure 9 A schematic diagram of the optical path of the projection system according to Embodiment Six of the present invention is shown;

[0033] Figure 10 The spectrum of blue light, green light, yellow fluorescence, and red light of a projection system according to an alternative embodiment of the present invention is shown.

[0034] The above figures include the following reference numerals:

[0035] 11. First light source; 12. Second light source; 13. Third light source; 20. First dissipation element; 21. First dissipation region; 22. Second dissipation region; 23. Third dissipation region; 31. First light guide plate; 32. Second light guide plate; 40. Second dissipation element; 41. First phase modulation region; 42. Second phase modulation region; 43. Phase modulation layer; 50. Third reflector; 60. Shaping lens group; 70. Compound eye structure; 80. Light homogenizing element; 91. First supplementary light source; 92. Second supplementary light source; 921. First supplementary part; 922. Second supplementary part; 93. Light combining device; 100. Light bar. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0038] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0039] To address the problem of poor speckle effect in existing projection systems, this invention provides a projection system.

[0040] like Figures 1 to 10As shown, the projection system includes a light source, a first dissipation element 20, a light guiding element, a second dissipation element 40, and a light homogenizing element 80. The first dissipation element 20 is located on the light-emitting side of the light source. The light guiding element is used to receive the light emitted from the light source that passes through the first dissipation element 20 along the first light path, and to make it pass through the first dissipation element 20 again along the second light path. The second dissipation element 40 is used to receive the light that passes through the first dissipation element 20 again along the second light path. The second dissipation element 40 includes at least two phase modulation regions, and the polarization state of the light passing through the at least two phase modulation regions is different. The light homogenizing element 80 is located on the light-emitting side of the second dissipation element 40, and the light beam emitted through the second dissipation element 40 enters the light homogenizing element 80.

[0041] By setting a first dissipation element 20 and a light guide on the light-emitting side of the light source, the light emitted from the light source along the first optical path is first dissipated by the first dissipation element 20, then deflected by the light guide and passes through the first dissipation element 20 a second time along the second optical path. This allows the light to pass through the first dissipation element 20 twice, achieving a double dissipation effect. This helps to ensure the dissipation effect while compressing the optical path volume, ensuring miniaturization. Simultaneously, a second dissipation element 40 is set, which is designed to include at least two phase modulation regions. The polarization state of the light passing through these two phase modulation regions is different, allowing the light that has been dissipated twice by the first dissipation element 20 to undergo further phase dissipation by the second dissipation element 40, further disrupting spatial coherence and greatly increasing the speckle elimination effect, ensuring high imaging quality of the projection system.

[0042] In one optional embodiment of this application, the light spot on the first dissipation element 20 along the first optical path partially overlaps with the light spot on the first dissipation element 20 along the second optical path; in another optional embodiment of this application, the light spot on the first dissipation element 20 along the first optical path does not overlap with the light spot on the first dissipation element 20 along the second optical path. Specifically, when the projection system includes a third reflector 50, and the third reflector 50 obliquely incidents the light emitted from the light source onto the first dissipation element 20, the light spot on the first dissipation element 20 along the first optical path partially overlaps with the light spot on the first dissipation element 20 along the second optical path. When the third reflector 50 is not provided, the light spot on the first dissipation element 20 along the first optical path and the light spot on the first dissipation element 20 along the second optical path do not overlap and are spaced apart.

[0043] refer to Figure 1The light guiding element includes one or more light guiding sheets. When there are multiple light guiding sheets, the multiple light guiding sheets include a first light guiding sheet 31 and a second light guiding sheet 32. The first light guiding sheet 31 and the second light guiding sheet 32 ​​are arranged at an angle. The first light guiding sheet 31 is used to receive light passing through the first dissipation element 20 along the first optical path and reflect the light to the second light guiding sheet 32. The second light guiding sheet 32 ​​is used to reflect the light along the second optical path. In an optional embodiment of this application, the first light guiding sheet 31 is a reflector, and the second light guiding sheet 32 ​​is a reflector or a dichroic mirror, which can be selected according to the actual situation.

[0044] Specifically, the aforementioned light source is capable of emitting three-color light. Specifically, the light source includes a first light source 11 emitting light in the first wavelength band, a second light source 12 emitting light in the second wavelength band, and a third light source 13 emitting light in the third wavelength band. A reflector is respectively provided on the light-emitting side of the first light source 11 to the third light source 13, so that the three-color light enters the first dissipation element 20 along the first optical path. The light divergence angle of at least one of the first light source 11 and the second light source 12 is smaller than the light divergence angle of the third light source 13, such as... Figure 4 As shown, the first dissipation element 20 includes a first dissipation region 21, a second dissipation region 22, and a third dissipation region 23. The diffusion angle of the dissipation region corresponding to one of the first light sources 11 and the second light source 12 is greater than the diffusion angle of the dissipation region corresponding to the third light source 13. In this application, the first light source 11 emits blue light, the second light source 12 emits green light, and the third light source 13 emits red light. The first light source 11 corresponds to the first dissipation region 21, and the second light source 12 corresponds to the second dissipation region 22. The diffusion angle of the first dissipation region 21 and the second dissipation region 22 is 10°. The third light source 13 corresponds to the third dissipation region 23, and the diffusion angle of the third dissipation region 23 is greater than or equal to 3° and less than or equal to 5°. Figure 4 It can be seen that the area of ​​the third dissipation zone 23 is larger than the area of ​​the first dissipation zone 21 and also larger than the area of ​​the second dissipation zone 22.

[0045] Specifically, the first dissipation element 20 is oscillating or rotatable, and is either a vibrating diffuser or a rotating diffuser wheel. The first dissipation element 20 is divided circumferentially into multiple dissipation zones, each fan-shaped, and at least two of these zones have different diffusion angles for different colors of light. Specifically, the multiple dissipation zones include a first dissipation zone 21, a second dissipation zone 22, and a third dissipation zone 23. The first dissipation element 20 is composed of these three zones, and the diffusion angles of the first and second dissipation zones 21 and 22 are different from those of the third dissipation zone 23. Different colors of light are assigned to different dissipation zones based on their respective illumination times.

[0046] like Figure 3As shown, the second dissipation element 40 includes multiple first phase modulation regions 41 and multiple second phase modulation regions 42. The first phase modulation regions 41 and the second phase modulation regions 42 are alternately arranged in a first direction and a second direction of the second dissipation element 40 to form a rectangular array. The first direction is perpendicular to the second direction, corresponding to the horizontal direction in the figure, and the second direction corresponds to the vertical direction in the figure. The polarization direction of the light passing through the first phase modulation region 41 is perpendicular to the polarization direction of the light passing through the second phase modulation region 42. For ease of understanding, Figure 3 The cells marked with number 1 represent the first phase modulation region 41, and the cells marked with number 2 represent the second phase modulation region 42. As shown in the figure, the top, bottom, left, and right sides of a first phase modulation region 41 are all second phase modulation regions 42, and the top, bottom, left, and right sides of a second phase modulation region 42 are all first phase modulation regions 41. According to the figure, using number 1 to represent the P state and number 2 to represent the S state, the polarization states of the entire light spot in each adjacent phase modulation region are made mutually perpendicular. This can also be understood as the polarization states of two adjacent phase modulation regions of the second dissipation element 40 in two mutually perpendicular directions being mutually perpendicular, thus destroying the spatial coherence of the entire light spot and eliminating speckle.

[0047] like Figure 2 As shown, the formation of the multiple first phase modulation regions 41 and multiple second phase modulation regions 42 is mainly achieved through the reasonable arrangement of the phase modulation layer 43, but it can also be achieved through coating. Specifically, the second dissipation element 40 includes a first phase modulation surface and a second phase modulation surface arranged opposite to each other. Figure 2 The left side corresponds to the first phase modulation surface. Figure 2 The right side corresponds to the second phase modulation surface. Both the first and second phase modulation surfaces include multiple phase modulation layers 43. The multiple phase modulation layers 43 of the first phase modulation surface are arranged at intervals along a first direction and extend along a second direction; the multiple phase modulation layers 43 of the second phase modulation surface are arranged at intervals along the second direction and extend along the first direction. The first direction is perpendicular to the second direction, corresponding to the horizontal direction in the figure, and the second direction corresponds to the vertical direction in the figure. The second dissipation element 40 also includes a substrate, which can be one or more. When there is only one substrate, the first phase modulation surface and the second phase modulation surface are respectively disposed on two side surfaces of the substrate; when there are multiple substrates, the first phase modulation surface and the second phase modulation surface are respectively disposed on two substrates and overlap with each other. This arrangement allows the first phase modulation surface and the second phase modulation surface to overlap, thereby forming phase modulation regions with different polarization states.

[0048] Optionally, the phase modulation layer 43 is a phase modulation sheet, such as a half-wave plate, to achieve changes in the polarization state of the transmitted light spot, namely the P-state and the S-state. Alternatively, the phase modulation layer 43 is a phase modulation film, such as a deposited mask.

[0049] refer to Figure 1 The homogenizing element 80 is a compound eye element, and at least one side surface of the compound eye element has a microlens array, which includes multiple microlenses. The size of the first phase modulation region 41 is less than or equal to the size of the microlenses; the size of the second phase modulation region 42 is less than or equal to the size of the microlenses. This ensures that each microlens emitting light from the compound eye element contains at least one polarization state. Preferably, both sides of the compound eye element of this application are provided with microlens arrays.

[0050] Specifically, the projection system also includes a shaping lens group 60, which is located between the first diffusing element 20 and the second diffusing element 40 or on the side of the homogenizing element 80 away from the second diffusing element 40. When the shaping lens group 60 is located on the side of the homogenizing element 80 away from the second diffusing element 40, the shaping lens group 60 consists of two biconvex lenses for beam shaping.

[0051] The projection system of this application will now be described in conjunction with specific embodiments and accompanying drawings.

[0052] Example 1

[0053] like Figures 1 to 4 As shown, the projection system of Embodiment 1 is described. Figure 1 The optical path diagram of the projection system of this embodiment is shown. Figure 2 The distribution diagram of the phase modulation layer 43 of the second dissipation element 40 in this embodiment is shown. Figure 3 The diagram shows the distribution of the first phase modulation region 41 and the second phase modulation region 42 of the second dissipation element 40 in this embodiment. Figure 4 A schematic diagram of the partitioning of the first dissipation element 20 in this embodiment is shown.

[0054] Depend on Figure 1 As shown, the projection system includes a light source, a first dissipation element 20, a light guiding element, a shaping lens group 60, a second dissipation element 40, and a light homogenizing element 80. The light guiding element includes multiple light guiding plates, namely a first light guiding plate 31 and a second light guiding plate 32. The light source includes a first light source 11 emitting blue light, a second light source 12 emitting green light, and a third light source 13 emitting red light. A beam splitter is provided on the light-emitting side of the first light source 11 and the third light source 13, and a reflector is provided on the light-emitting side of the second light source 12. The light emitted from the three light sources is combined into a single beam through the beam splitter and the reflector. The light source and the light guiding element are respectively located on both sides of the first dissipation element 20, and the shaping lens group 60, the second dissipation element 40, and the light homogenizing element 80 are located on the side where the light source is located.

[0055] In this embodiment, the tri-color light emitted from the light source is amplified after passing through the first dissipation element 20 along the first optical path, which also has a certain effect on eliminating speckle. Then, after being reflected by the first light guide plate 31 and the second light guide plate 32 in sequence, the optical path is deflected to reduce the volume, so that the light beam passes through the first dissipation element 20 again along the second optical path for a second dissipation, further reducing the speckle degree. However, at this time, the first dissipation element 20 also brings the side effect of amplifying the beam angle. After passing through the shaping lens group 60, the light beam is amplified and the divergence angle is reduced. It then penetrates the second dissipation element 40, dividing the entire beam spot into multiple phase polarization states, and then enters the homogenizing element 80, thereby ensuring that each microlens illuminating the homogenizing element 80 has at least one polarization state of light, and that the polarization state is different from the light received by the adjacent microlens.

[0056] In this embodiment, the first optical path and the second optical path are parallel, and the light spot on the first dissipation element 20 along the first optical path and the light spot on the first dissipation element 20 along the second optical path do not overlap and are spaced apart.

[0057] Furthermore, the first light guide plate 31 and the second light guide plate 32 can also perform periodic scanning at a certain small angle, so that the beam scans to different positions of the homogenizing element 80, thereby disrupting the temporal coherence of the speckle and reducing the speckle intensity. In addition, a beam-shrinking lens group is also added between the light source and the first dissipation element 20 to shrink the beam of the light spot or multiple laser light sources and reduce the size of the light spot.

[0058] Example 2

[0059] like Figure 5 As shown, the projection system of Embodiment 2 is described.

[0060] The difference between this embodiment and Embodiment 1 is that a third reflecting mirror 50 is added.

[0061] Specifically, the projection system includes a light source, a third reflector 50, a first diffusing element 20, a light guiding element, a shaping lens group 60, a second diffusing element 40, and a light homogenizing element 80. The light guiding element includes a first light guiding plate 31 and a second light guiding plate 32. The light source includes a first light source 11 emitting blue light, a second light source 12 emitting green light, and a third light source 13 emitting red light. A beam splitter is provided on the light-emitting side of the first light source 11 and the third light source 13, and a reflector is provided on the light-emitting side of the second light source 12. The light emitted from the three light sources is combined into a single beam through the beam splitter and the reflector.

[0062] In this embodiment, the light emitted from the light source is reflected by the third reflecting mirror 50 and then obliquely incident on the first dissipation element 20. After being dissipated by the first dissipation element 20, it is further reflected sequentially by the first light guiding plate 31 and the second light guiding plate 32, passing through the first dissipation element 20 a second time along the second optical path. The subsequent optical path is the same as in Embodiment 1, and can be referred to the description in Embodiment 1. In this embodiment, by obliquely incidenting the light beam on the first dissipation element 20, it is beneficial to reduce the size of the first dissipation element 20. At the same time, the tilt angle of the third reflecting mirror 50 can be adjusted, so that the position of the light illuminating the first dissipation element 20 along the first optical path can be changed according to adjusting the tilt position of the third reflecting mirror 50. Alternatively, the third reflecting mirror 50 can be set to scan and vibrate, so that the light beam scans to different positions of the homogenizing element 80, destroying the temporal coherence of the speckle and reducing the speckle.

[0063] In this embodiment, the first optical path and the second optical path are arranged at an angle, and the light spot on the first dissipation element 20 along the first optical path partially overlaps with the light spot on the first dissipation element 20 along the second optical path.

[0064] Example 3

[0065] like Figure 6 As shown, the projection system of Embodiment 3 is described.

[0066] The difference between this embodiment and Embodiment 1 is that a compound eye structure 70 is added between the light source and the first dissipation element 20. The compound eye structure 70 is located in the first optical path from which the light source is emitted. This compound eye structure 70 can be a structure with a microlens array on one side or a structure with a microlens array on both sides. The compound eye structure 70 first homogenizes the light emitted from the light source to improve the uniformity of the system, and at the same time, it disperses the light beam, which is also beneficial for dissipation.

[0067] Example 4

[0068] like Figure 7 As shown, the projection system of Embodiment 4 is described.

[0069] The difference between this embodiment and Embodiment 1 is that the projection system further includes a light bar 100, which is located on the light-emitting side of the shaping lens group 60. Specifically, the light-diffusing element 80, the shaping lens group 60, and the light bar 100 are arranged sequentially in a direction away from the second dissipation element 40.

[0070] In this embodiment, the light beam emitted from the second dissipation element 40 passes through the light homogenizing element 80 and then enters the light bar 100 through the shaping lens group 60. The angular diversity of the light bar 100 further eliminates speckle and homogenizes the light.

[0071] Example 5

[0072] like Figure 8 As shown, the projection system of Embodiment 5 is described.

[0073] The difference between this embodiment and Embodiment 3 is that the projection system further includes a second supplementary light source 92. The second supplementary light source 92 includes a first supplementary part 921 and a second supplementary part 922. The second supplementary light emitted from the first supplementary part 921 is reflected by the second light guide plate 32 to the second supplementary part 922 and excites the second supplementary part 922 to form fluorescence. The fluorescence is transmitted through the second light guide plate 32 and incident on the first dissipation element 20 along the second light path. By adding a supplementary light source, a hybrid projection system is obtained.

[0074] In this embodiment, the first supplementary part 921 is a laser lamp, the second supplementary light emitted by the first supplementary part 921 is a blue laser, and the second supplementary part 922 is a CG LED lamp or a green phosphor. The blue laser is reflected by the second light guide and then excites the second supplementary part 922 to form green fluorescence. The green fluorescence is guided by the transmission of the second light guide plate 32 to be incident on the first dissipation element 20 along the second light path.

[0075] Example 6

[0076] like Figure 9 As shown, the projection system of Embodiment Six is ​​described.

[0077] The difference between this embodiment and embodiment three is that the projection system also includes a first supplementary light source 91 and a light combining device 93. The light combining device 93 is located between the first dissipation element 20 and the second dissipation element 40. The first supplementary light emitted from the first supplementary light source 91 is deflected by the light combining device 93 and then incident on the second dissipation element 40.

[0078] In this embodiment, the light combining device 93 is a dichroic mirror, or a structure with a film layer in the middle region, or a structure with a hollow middle region.

[0079] Specifically, when the first supplementary light source 91 is a red LED emitting red light of a first wavelength, the light combining device 93 combines the wavelengths and uses a dichroic mirror to transmit red laser light of a second wavelength and reflect red light of the first wavelength. When the first supplementary light source 91 is a green LED emitting green light of a first wavelength, the light combining device 93 has a coated middle region or a hollowed-out middle region. In this case, the middle region of the light combining device 93 transmits green laser light of a second wavelength and reflects green light of the first wavelength. When the first supplementary light source 91 is a yellow fluorescent component emitting yellow fluorescence, the light combining device 93 combines the wavelengths and uses a dichroic mirror to reflect the yellow fluorescence. The transmission and reflection characteristics of the light combining device 93 are described in [reference needed]. Figure 10The green laser and yellow fluorescence spectra overlap, resulting in spectral loss. In the figure, B-LD represents blue laser, G-LD represents green laser, Y-fluorescence represents yellow fluorescence, and R-LD represents red laser.

[0080] Example 7

[0081] The difference between this embodiment and embodiment three is that the light guiding element in this embodiment is a light guiding sheet.

[0082] In this embodiment, the light emitted from the light source passes through the compound eye structure 70 and then obliquely enters the first dissipation element 20 along the first optical path. After passing through the first dissipation element 20, it is received by the light guide plate, which then obliquely enters the first dissipation element 20 along the second optical path. Specifically, the direction of the incident light path of the light guide plate is set at an angle to the direction of the outgoing light path. This embodiment uses only one light guide plate, saving components, compressing space, and facilitating the miniaturization of the projection system.

[0083] In summary, the projection system of this application outputs multiple frames of images, each frame including at least three or five timing sequences. The three timing sequences include the first, second, and third timing sequences below, and the five timing sequences include the first, second, third, fourth, and fifth timing sequences. Here, the terms "first," "second," "third," etc., are only used to define the timing sequence type and do not limit the order of the three or five timing sequences. In other words, there is no specific order among the three or five timing sequences.

[0084] The first timing sequence is the blue light timing sequence: the blue light emitted from the first light source 11 passes sequentially through the first dissipation zone 21 of the first dissipation element 20, the first light guide plate 31, the second light guide plate 32, the second dissipation zone 22 of the first dissipation element 20, and the second dissipation element 40 before being incident on the uniform light element 80.

[0085] The second timing sequence is the green light timing sequence: the green laser emitted from the second light source 12 passes sequentially through the first dissipation region 21 of the first dissipation element 20, the first light guide plate 31, the second light guide plate 32, the second dissipation region 22 of the first dissipation element 20, and the second dissipation element 40 before being incident on the homogenizing element 80; when the second supplementary light source 92 is included, the green light timing sequence also includes: green fluorescence passing through the second light guide plate 32 and being incident on the homogenizing element 80 behind it; when the first supplementary light source 91 is included, the green light timing sequence also includes: the first supplementary light passing through the light combining device 93 and being incident on the homogenizing element 80, at this time, the first supplementary light is green light.

[0086] The third timing sequence is the red light timing sequence: the light emitted from the third light source 13 passes sequentially through the first dissipation region 21 of the first dissipation element 20, the first light guide plate 31, the second light guide plate 32, the second dissipation region 22 of the first dissipation element 20, and the second dissipation element 40 before entering the homogenizing element 80; when the second supplementary light source 92 is included, the red light timing sequence also includes: fluorescence passing through the second light guide plate 32 and entering the homogenizing element 80 behind it; when the first supplementary light source 91 is included, the red light timing sequence also includes: the first supplementary light passing through the light combining device 93 and entering the homogenizing element 80, at this time, the first supplementary light is red light.

[0087] The three timing sequences described above all involve lighting only one light source at a time. Of course, it is also possible to light up two light sources simultaneously.

[0088] In the fourth timing sequence, the first light source 11 and the second light source 12 emit light simultaneously, and the emitted light sequentially passes through the first dissipation region 21 of the first dissipation element 20, the first light guide plate 31, the second light guide plate 32, the second dissipation region 22 of the first dissipation element 20, and the second dissipation element 40 before entering the homogenizing element 80. When the second supplementary light source 92 is included, the fluorescence passes through the second light guide plate 32 and enters the homogenizing element 80 behind it; when the first supplementary light source 91 is included, the first supplementary light passes through the light combining device 93 and enters the homogenizing element 80. Blue light and green light are emitted simultaneously to form cyan light.

[0089] In the fifth timing sequence, the second light source 12 and the third light source 13 emit light simultaneously, and the emitted light sequentially passes through the first dissipation region 21 of the first dissipation element 20, the first light guide plate 31, the second light guide plate 32, the second dissipation region 22 of the first dissipation element 20, and the second dissipation element 40 before entering the homogenizing element 80. When the second supplementary light source 92 is included, the fluorescence passes through the second light guide plate 32 and enters the homogenizing element 80 behind it; when the first supplementary light source 91 is included, the first supplementary light passes through the light combining device 93 and enters the homogenizing element 80. Red light and green light are emitted simultaneously to form yellow light.

[0090] Because the green light is on for a longer period of time, the overall brightness of the white field is greatly improved.

[0091] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0092] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0093] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A projection system, characterized in that, include: light source; The first dissipation element (20) is located on the light-emitting side of the light source; A light guiding element is used to receive light emitted from the light source that passes through the first dissipation element (20) along the first light path, and cause it to pass through the first dissipation element (20) again along the second light path; The second dissipation element (40) is used to receive light that passes through the first dissipation element (20) again along the second optical path. The second dissipation element (40) includes at least two phase modulation regions, and the polarization state of the light passing through the at least two phase modulation regions is different. A light-diffusing element (80) is located on the light-emitting side of the second light-dissipating element (40), and the light beam emitted through the second light-dissipating element (40) enters the light-diffusing element (80).

2. The projection system according to claim 1, characterized in that, The light spot on the first dissipation element (20) along the first optical path may or may not overlap with the light spot on the first dissipation element (20) along the second optical path.

3. The projection system according to claim 1, characterized in that, The light guiding element includes one or more light guiding sheets. When there are multiple light guiding sheets, the multiple light guiding sheets include a first light guiding sheet (31) and a second light guiding sheet (32). The first light guiding sheet (31) and the second light guiding sheet (32) are arranged at an angle. The first light guiding sheet (31) is used to receive light passing through the first dissipation element (20) along the first light path and reflect the light to the second light guiding sheet (32). The second light guiding sheet (32) is used to reflect the light along the second light path.

4. The projection system according to claim 1, characterized in that, The light source includes a first light source (11) emitting light in a first wavelength band, a second light source (12) emitting light in a second wavelength band, and a third light source (13) emitting light in a third wavelength band. The light divergence angle of at least one of the first light source (11) and the second light source (12) is smaller than that of the third light source (13). The first dissipation element (20) includes a first dissipation region (21), a second dissipation region (22), and a third dissipation region (23). The diffusion angle of the dissipation region corresponding to one of the first light source (11) and the second light source (12) is larger than that of the dissipation region corresponding to the third light source (13).

5. The projection system according to claim 1, characterized in that, The first dissipation element (20) is arranged to vibrate or rotate. The first dissipation element (20) is divided into multiple dissipation zones along the circumference. The multiple dissipation zones are fan-shaped. At least two of the multiple dissipation zones have different diffusion angles for different colors of light.

6. The projection system according to claim 1, characterized in that, The second dissipation element (40) includes a plurality of first phase modulation regions (41) and a plurality of second phase modulation regions (42). The first phase modulation regions (41) and the second phase modulation regions (42) are alternately arranged in a first direction and a second direction of the second dissipation element (40). The first direction is perpendicular to the second direction. The polarization direction of the light passing through the first phase modulation region (41) is perpendicular to the polarization direction of the light passing through the second phase modulation region (42).

7. The projection system according to claim 1, characterized in that, The light-diffusing element (80) is a compound eye element, and at least one side surface of the compound eye element has a microlens array, the microlens array including a plurality of microlenses, and the size of the phase modulation region is less than or equal to the size of the microlenses.

8. The projection system according to claim 1, characterized in that, The second dissipation element (40) includes a first phase modulation surface and a second phase modulation surface disposed opposite to each other, and both the first phase modulation surface and the second phase modulation surface include multiple phase modulation layers (43). The plurality of phase modulation layers (43) of the first phase modulation surface are arranged at intervals along a first direction and all extend along a second direction; The plurality of phase modulation layers (43) of the second phase modulation surface are arranged at intervals along the second direction and all extend along the first direction; The first direction is perpendicular to the second direction.

9. The projection system according to claim 1, characterized in that, The projection system further includes a third reflector (50), which is used to obliquely direct the light emitted from the light source into the first dissipation element (20).

10. The projection system according to claim 1, characterized in that, The projection system further includes a shaping lens group (60), which is located between the first diffusing element (20) and the second diffusing element (40) or on the side of the light-diffusing element (80) away from the second diffusing element (40). When the shaping lens group (60) is located on the side of the light-diffusing element (80) away from the second diffusing element (40), the projection system further includes a light bar (100), which is located on the light-emitting side of the shaping lens group (60).

11. The projection system according to claim 1, characterized in that, The projection system also includes a compound eye structure (70), which is located on the first light path from which the light source is emitted.

12. The projection system according to claim 4, characterized in that, The projection system further includes a first supplementary light source (91) and a light combining device (93). The light combining device (93) is located between the first dissipation element (20) and the second dissipation element (40). The first supplementary light emitted from the first supplementary light source (91) is incident on the second dissipation element (40) via the light combining device (93); or The projection system further includes a second supplementary light source (92), which includes a first supplementary part (921) and a second supplementary part (922). The second supplementary light emitted from the first supplementary part (921) is reflected by the light guiding element to the second supplementary part (922) and excites the second supplementary part (922) to form fluorescence. The fluorescence is transmitted through the light guiding element and incident on the first dissipation element (20) along the second light path.

13. The projection system according to claim 1, characterized in that, The light source includes a first light source (11), a second light source (12), and a third light source (13). The projection system outputs multiple frames of images, each frame of which includes at least a first time sequence, a second time sequence, and a third time sequence. The first timing sequence is that the light emitted from the first light source (11) is incident on the light homogenizing element (80); The second timing is that the light emitted from the second light source (12) is incident on the homogenizing element (80), and / or the fluorescence or the first supplementary light is incident on the homogenizing element (80); The third timing sequence is that the light emitted from the third light source (13) is incident on the homogenizing element (80); and / or the fluorescence or the first supplementary light is incident on the homogenizing element (80).

14. The projection system according to claim 13, characterized in that, Each frame of the image also includes a fourth time sequence and a fifth time sequence. The fourth timing sequence is that the first light source (11) and the second light source (12) emit light simultaneously, and the emitted light is incident on the light homogenizing element (80), and / or fluorescence or the first supplementary light is incident on the light homogenizing element (80); The fifth timing sequence is that the second light source (12) and the third light source (13) emit light simultaneously, and the emitted light is incident on the homogenizing element (80), and / or fluorescence or the first supplementary light is incident on the homogenizing element (80).

15. The projection system according to claim 1, characterized in that, The projection system further includes a first supplementary light source (91) and a light combining device (93). The light combining device (93) is located between the first dissipation element (20) and the second dissipation element (40). The first supplementary light emitted from the first supplementary light source (91) is incident on the second dissipation element (40) through the light combining device (93). The light combining device (93) is a dichroic mirror, or a structure with a film layer in the middle region, or a structure with a hollow middle region.

Images