Projection apparatus and projection system

Abstract

Disclosed in the present application are a projection apparatus and a projection system. A diffractive optical element is provided and is provided with a plurality of zones, each zone corresponding to laser light of one color; the diffractive optical element moves according to the color of laser light emitted by a laser light source, such that the laser light of different colors emitted by the laser light source is respectively incident to the corresponding zones of the diffractive optical element; and each zone collimates the incident laser light beams of the corresponding color. Therefore, after collimating the laser light of different colors emitted by a laser, the diffractive optical element irradiates same to a phase light modulator device according to different time sequences, thereby improving the efficiency of the diffractive optical element in collimating laser light beams of multiple colors, and further improving the projection display effect.

Description

Projection device and projection system

[0001] Cross-reference to Related Applications

[0002] This application claims priority to the Chinese Patent Application No. 202410855768.0, filed on June 28, 2024, and entitled “A projection device”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of projection technology, in particular to a projection device and a projection system. BACKGROUND

[0004] Projection display is a technology that controls a light source by plane image information, and uses an optical system and a projection space to magnify and display an image on a projection screen. With the development of projection display technology, projection display is gradually applied to business activities, conference exhibitions, scientific education, military command, traffic management, centralized monitoring and advertising entertainment, etc. Its advantages such as large display screen size and clear display are also suitable for the requirements of large screen display.

[0005] In a projection system, a phase light modulator (PLM) device is applied to modulate the phase of an incident laser beam. The light intensity distribution of the laser beam emitted by the PLM can make the brighter areas in the image to be displayed brighter and the darker areas darker, thereby improving the projection display effect. SUMMARY

[0006] Embodiments of the present application provide a projection device, comprising:

[0007] a laser light source configured to emit laser beams of multiple colors in time division;

[0008] a diffractive optical element located on the light emitting side of the laser light source; the diffractive optical element comprises a plurality of sub-zones, each sub-zone corresponding to a color of laser light; the diffractive optical element is configured to move when the laser light source emits laser light, so that laser light of different colors emitted by the laser light source is incident to the corresponding sub-zone of the diffractive optical element respectively; each sub-zone of the diffractive optical element is configured to collimate the incident laser beam of the corresponding color;

[0009] a phase light modulator located on the light emitting side of the diffractive optical element; the phase light modulator is configured to modulate the phase of the incident laser beam according to an image to be displayed; and

[0010] a display element located on the light emitting side of the phase light modulator, configured to modulate the brightness of the incident laser beam according to the driving data of the image to be displayed to form a display image.

[0011] The application also provides a projection system, comprising:

[0012] a projection device as described above; and

[0013] a projection screen located on the light exit side of the projection device. BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. 1 is a schematic structural diagram of a projection device according to an embodiment of the application;

[0015] FIG. 2 is a schematic structural diagram of a projection device according to another embodiment of the application;

[0016] FIG. 3 is a schematic diagram of a partition of a diffractive optical element 50 according to an embodiment of the application;

[0017] FIG. 4 is a schematic diagram of a connection of the diffractive optical element 50 to a driving device 60 according to an embodiment of the application;

[0018] FIG. 5 is a schematic diagram of a phase of the diffractive optical element 50 according to an embodiment of the application;

[0019] FIG. 6a is a schematic diagram of a distance setting calculation process of a light combination element 102 and the diffractive optical element 50 according to an embodiment of the application;

[0020] FIG. 6b is a schematic structural diagram of a laser light source 10, the diffractive optical element 50 and a phase light modulation device 40 according to an embodiment of the application;

[0021] FIG. 7a is a schematic diagram of a light spot formed by a red laser of a double light emitting point at a position 601 of FIG. 6b in a light path space according to an embodiment of the application;

[0022] FIG. 7b is a schematic diagram of a light spot formed by a red laser of a double light emitting point at a position 602 of FIG. 6b in a light path space according to an embodiment of the application;

[0023] FIG. 7c is a schematic diagram of a light spot formed by a red laser of a double light emitting point at a position 603 of FIG. 6b in a light path space according to an embodiment of the application;

[0024] FIG. 7d is a schematic diagram of a light spot formed by a red laser of a double light emitting point at a position 604 of FIG. 6b in a light path space according to an embodiment of the application;

[0025] FIG. 7e is a schematic diagram of a light spot formed by a red laser of a double light emitting point emitted by a red light laser chip in FIG. 6b without passing through the diffractive optical element and directly irradiating the phase light modulation device;

[0026] FIG. 8 is a schematic structural diagram of a projection device according to an embodiment of the application;

[0027] FIG. 9 is a second structural schematic diagram of a projection device according to an embodiment of the present application;

[0028] FIG. 10 is a structural schematic diagram of a reflective phase light modulation device according to an embodiment of the present application;

[0029] FIG. 11 is a structural schematic diagram of a transmissive phase light modulation device according to an embodiment of the present application;

[0030] FIG. 12 is a structural schematic diagram of a projection system according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the above objectives, features and advantages of the present application more apparent, further description will be made to the present application with reference to the accompanying drawings and embodiments. However, the example embodiments can be implemented in various forms, and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present application more comprehensive and complete, and to fully convey the ideas of the example embodiments to those skilled in the art. The same reference signs in the drawings represent the same or similar structures, and thus repeated description thereof will be omitted. The expressions of position and direction described in the present application are described with reference to the drawings, but can be changed as needed, and the changes made are included in the protection scope of the present application. The drawings of the present application are only used to illustrate the relative positional relationship and do not represent the true proportions.

[0032] Projection display is a technology of controlling a light source by plane image information, and using an optical system and a projection space to magnify and display an image on a projection screen. With the development of projection display technology, projection display is gradually applied to business activities, conference exhibitions, scientific education, military command, traffic management, centralized monitoring and advertising entertainment, and has advantages such as a larger display screen size and clear display, which are also suitable for the requirements of large screen display.

[0033] The projection system can include a laser light source, a display element and a projection lens. A laser beam emitted by the laser light source is incident on the display element to be amplitude modulated to form an image beam, and the image beam is imaged by the projection lens.

[0034] In the projection system, the application of PLM can modulate the phase of the laser beam before the laser beam is incident on the display element. The PLM needs to modulate the phase of the laser beam according to the brightness distribution of the image to be displayed. The light intensity distribution of the laser beam emitted by the PLM can make the brighter area of the image to be displayed brighter and the darker area darker, thereby improving the contrast of the displayed image and improving the projection display effect.

[0035] However, for the laser beams of multiple colors, the divergence angles of the laser beams of different colors are different, and as the laser beams of multiple colors continue to propagate for a period of time, the divergence of the laser beams of each color becomes larger, affecting the diffraction efficiency of the phase light modulation device and affecting the projection display effect.

[0036] Therefore, an embodiment of the present application provides a projection device, as shown in FIG. 1, which comprises a laser light source 10, an illumination system 20 and a projection lens 30. The illumination system 20 is located on the light exit side of the laser light source 10, and the illumination system 20 comprises a display element 201. The projection lens 30 is located on the light exit side of the display element 201.

[0037] The laser light source 10 can adopt a monochromatic laser, or a laser that can emit laser beams of multiple colors, or multiple lasers that emit laser beams of different colors. When the laser light source 10 adopts a monochromatic laser, a color conversion device and a color wheel also need to be arranged in the laser light source 10. The color conversion device is used for color conversion, and the color wheel is used for filtering monochromatic light. The monochromatic laser cooperates with the color conversion device and the color wheel to realize the emission of primary color light of different colors in time sequence. When the laser light source 10 adopts a laser that can emit laser beams of multiple colors, the laser light source needs to be controlled to emit laser beams of different colors as primary color light in time sequence.

[0038] In the embodiment of the present application, a three-color laser light source can be adopted, which comprises a laser chip array composed of a red laser chip, a green laser chip and a blue laser chip, and is used for emitting three primary color lasers, such as an MCL laser and the like. The three-color laser light source can also comprise a red laser, a green laser and a blue laser respectively emitting three primary color lasers.

[0039] The laser light source 10 can also comprise a light combining assembly for combining three-color laser light. The light combining assembly can comprise a mirror and a dichroic mirror. The number and setting position of the mirror and the dichroic mirror are set according to the arrangement rule of the laser chips in the laser, so as to realize the combination of three-color laser light.

[0040] The illumination system 20 is located on the light exit side of the laser light source 10, and the illumination system 20 comprises a display element 201. On the one hand, the illumination system 20 shapes and homogenizes the emitted light beams of the laser light source 10, and on the other hand, the emitted light beams of the laser light source 10 can be incident on the display element 201 at a suitable angle, so as to generate a display image by amplitude modulation of the incident light rays. The illumination system 20 can also comprise a light homogenizing element 202, a plurality of lenses or lens groups 203, so that the illumination light beams are homogenized and shaped before being incident on the display element 201. The light homogenizing element 202 can adopt a light pipe or a compound eye lens group, which is not limited herein.

[0041] The projection device provided by the embodiments of the present application can adopt a digital light processing (DLP) system, and the display element 201 can adopt a digital micromirror device (DMD). The surface of the DMD includes a plurality of tiny mirrors, each of which can be driven to deflect individually, and the display image is generated by controlling the deflection angle of the DMD and the brightness of the reflected light of each tiny mirror. In addition, the display element 201 can also adopt a liquid crystal on silicon (LCoS) device or a liquid crystal display (LCD) device, and the embodiments of the present application take the DMD as an example for illustration.

[0042] The projection lens 30 is used for imaging the outgoing light of the display element 201, so that the audience can watch a larger size display image.

[0043] As shown in FIG. 1, the projection device further includes a phase light modulation device 40 located between the light exit side of the laser light source 10 and the light entrance side of the illumination system 20, which is used for phase modulation of the incident laser beam according to the image to be displayed. The phase light modulation device is sensitive to the wavelength and incident angle of the incident light beam, and in the embodiments of the present application, the laser light source adopts a three-color laser light source, which can emit red laser beams, green laser beams and blue laser beams. Due to the arrangement of the laser chips, the spot size of the red laser beam incident on the phase light modulation device 40 is larger than that of the blue laser beam, and also larger than that of the green laser beam. In addition, the divergence angle of the red laser beam is larger than that of the blue laser beam, and also larger than that of the green laser beam. If the red laser beam, the blue laser beam and the green laser beam irradiated on the phase light modulation device are not processed, the output image of the phase light modulation device 40 will have ghosting problems.

[0044] In order to overcome the above problems, a diffractive optical element can be arranged in the light projection device, which can shape the incident laser beam, so that the laser beam incident on the PLM is more collimated and has a consistent size.

[0045] In some embodiments, the red laser chip in the three-color laser emits a laser beam with double light emitting points. The red laser beam, the blue laser beam and the green laser beam just emitted by the laser light source 10 do not overlap in the light path space, but the red laser beam emitted by the double light emitting points overlaps in the light path space. After propagating for a distance, the light spots formed by the double light emitting points will be separated from each other.

[0046] If the diffractive optical element is arranged near the light emitting surface of the laser in the laser light source 10, the diffractive optical element cannot collimate the red laser beam of the double light emitting point.

[0047] If the diffractive optical element is arranged at the position after the light combination in the laser light source 10, since the red laser beam, the blue laser beam and the green laser beam are overlapped in the optical path space after the light combination, the diffractive optical element cannot have high diffraction efficiency for the three color lasers respectively.

[0048] Considering the above factors, as shown in FIG. 2, the diffractive optical element 50 is arranged between the light emitting side of the laser light source 10 and the light entering side of the phase light modulation device 40, and the laser light source 10 is arranged at a certain distance from the diffractive optical element 50. The diffractive optical element 50 is arranged to include a plurality of sub-zones, each of which corresponds to a color of laser. The diffractive optical element 50 is moved according to the color of the laser emitted by the laser light source 10, so that the different colors of laser emitted by the laser light source 10 are respectively incident on the corresponding sub-zone of the diffractive optical element 50. Different sub-zones of the diffractive optical element 50 can efficiently diffract the incident laser beams of different colors, so that the emitted laser beams are collimated and incident on the phase light modulation device 40.

[0049] For example, as shown in FIG. 3, the diffractive optical element 50 includes a first sub-zone 501, a second sub-zone 502 and a third sub-zone 503. The red laser, the green laser and the blue laser emitted by the laser light source 10 are respectively incident on the first sub-zone 501, the second sub-zone 502 and the third sub-zone 503 of the diffractive optical element 50. FIG. 3 shows that the diffractive optical element is arranged in a circular shape. Arranging each sub-zone in a sector shape is only an example, and the specific shape of each sub-zone is not limited in the present application, and can be adjusted according to actual application.

[0050] In some embodiments, as shown in FIG. 4, the diffractive optical element 50 can also be connected to a driving device 60 for driving the diffractive optical element 50 to rotate in a plane perpendicular to the laser emitting direction of the laser light source 10. The rotation speed of the driving device 60 matches the time duty ratio corresponding to the emission of various color lasers of the laser light source 10. Each sub-zone of the diffractive optical element 50 can be arranged in a sector shape, and the sub-zones of each sector are arranged in sequence around the rotation axis of the diffractive optical element 50.

[0051] In specific implementation, each sub-zone of the diffractive optical element 50 can include a plurality of diffractive microstructures, and the phase distribution of the diffractive microstructures in each sub-zone is different. The diffractive microstructure can be one of a multi-step structure, a sub-wavelength nano antenna or a photonic sieve. Here, only the specific structural composition of the diffractive microstructure is exemplified, and the specific structural composition of the diffractive microstructure is not limited in the present application. Any structural composition that can realize the function of the diffractive microstructure belongs to the protection scope of the present application.

[0052] Taking the multi-step structure as an example, the calculation of the radial phase of each sub-zone of the diffractive optical element 50 is illustrated as follows, and the radial sag of the diffractive optical element 50 satisfies the following formula (I):

[0053] wherein Zsag represents the radial sag of the diffractive optical element, c represents the reciprocal of the radius of curvature, k represents the conic coefficient, r represents the position in the radial direction, a1, a2, a3, a4 represent the aspheric coefficients of the 2nd order, 4th order, 8th order and 16th order respectively. The parameters in the above formula (I) can be calculated by optical design software such as Zemax, CodeV, or algorithms such as GS algorithm, simulated annealing, recursion, and the like, as well as the parameters such as the divergence angle and the central position of the incident laser beam of the diffractive optical element.

[0054] According to the above formula (I), the phase of the diffractive optical element 50 satisfies the following formula (II):

[0055] wherein represents the phase, n represents the refractive index of the diffractive optical element, and λ represents the wavelength of the incident laser. The mod represents the remainder calculation, which realizes the abandonment of the redundant propagation phase by taking the remainder of the continuous phase with respect to 2π, so as to achieve more accurate phase control.

[0056] Further, the radial phase of each sub-zone of the diffractive optical element 50 satisfies the following formula (III):

[0057] wherein d λ represents the area of the laser spot incident to the sub-zone of the diffractive optical element, θ λ represents the divergence angle of the laser beam incident to the sub-zone, λ represents the wavelength of the laser beam incident to the sub-zone, and r represents the radial position of the laser beam incident to the sub-zone.

[0058] FIG. 5 shows a phase diagram of the diffractive optical element 50 according to an embodiment of the present application.

[0059] As shown in FIG. 5, the diffractive optical element 50 includes three sub-zones, and the three sub-zones can cover 2π phase. Each sub-zone includes a plurality of diffractive microstructures with multi-step structures. It is assumed that the laser beam incident to the diffractive optical element 50 includes red laser, green laser and blue laser, and the phase distribution corresponding to different color lasers is different, and the step height and size in the diffractive microstructure can also be different.

[0060] According to the above formula (I) to formula (III), the radial phases of different color lasers of each sub-zone of the diffractive optical element 50 in FIG. 5 satisfy the following formula (IV), formula (V) and formula (VI) respectively:

[0061] wherein, d λ1 represents the area of the red laser light spot incident to the subzone of the diffractive optical element, θ λ1 represents the divergence angle of the red laser light beam incident to the subzone, λ1 represents the wavelength of the red laser light beam incident to the subzone, and x represents the radial position of the red laser light beam incident to the subzone.d λ2 represents the area of the green laser light spot incident to the subzone of the diffractive optical element, θ λ2 represents the divergence angle of the green laser light beam incident to the subzone, λ2 represents the wavelength of the green laser light beam incident to the subzone, and y represents the radial position of the green laser light beam incident to the subzone.d λ3 represents the area of the blue laser light spot incident to the subzone of the diffractive optical element, θ λ3 represents the divergence angle of the blue laser light beam incident to the subzone, λ3 represents the wavelength of the blue laser light beam incident to the subzone, and z represents the radial position of the blue laser light beam incident to the subzone.

[0062] FIG. 6a shows a schematic diagram of a distance setting calculation process of a light combining element and a diffractive optical element according to an embodiment of the present application; and FIG. 6b shows a schematic diagram of a structure of a laser light source, a diffractive optical element, and a phase light modulating device according to an embodiment of the present application.

[0063] In some embodiments, as shown in FIGS. 6a and 6b, the laser light source 10 includes a laser and a light combining assembly 102. The laser includes a laser chip array 101, which includes a plurality of laser chips, and the colors of the laser light emitted by the different laser chips are different. The light combining assembly 102 is located on the light emitting side of the laser chip array 101 and is configured to combine the laser light of different colors. The diffractive optical element 50 is located between the light combining assembly 102 and the phase light modulating device 40.

[0064] In a specific implementation, the laser chip array 101 can include a red laser chip 101-1, a green laser chip 101-2, and a blue laser chip 101-3, and the light combining assembly 102 can include a first mirror 102-1, a first dichroic plate 102-2, and a second dichroic plate 102-3. The first mirror 102-1 corresponds to the position of the red laser chip 101-1, the first dichroic plate 102-2 corresponds to the position of the green laser chip 101-2, and the second dichroic plate 102-3 corresponds to the position of the blue laser chip 101-3. The first mirror 102-1 is configured to reflect the red laser light beam, the first dichroic plate 102-2 is configured to transmit the red laser light beam and reflect the green laser light beam, and the second dichroic plate 102-3 is configured to transmit the red laser light beam, transmit the green laser light beam, and reflect the blue laser light beam.

[0065] Due to the mounting process error between the red laser chip 101-1 and the corresponding collimating lens, there is a certain distance difference between the two light emitting points on the light emitting surface of the double light emitting points. After the red laser of the double light emitting points is collimated by the collimating lens, the divergence angle between the two optical axes becomes smaller, which can be 0.1 o When the red laser of the double light emitting points is incident on the diffractive optical element 50 through the light combination assembly 102-1, the spot size of each light emitting point on the diffractive optical element 50 will not be too large, but the distance between the center points of the spots formed by the two light emitting points will become larger. Therefore, the spots of the red laser of the two light emitting points on the diffractive optical element 50 are separated.

[0066] As shown in FIG. 6a, assuming that the distance between the two light emitting points on the light emitting surface of the red laser chip 101-1 is S1, the set distance between the diffractive optical element 50 and the light combination assembly 102-1 is d, and the spot magnification of the red laser of the double light emitting points after propagating a distance d after exiting the light combination assembly 102-1 is N, then the distance S2 between the red laser of the double light emitting points on the diffractive optical element 50 is S2=N*S1. At the same time, according to the collimation of the red laser by the corresponding collimating lens of the red laser chip 101-1, it can be determined that the divergence angle of the red laser of the double light emitting points after exiting the light combination assembly 102-1 is a constant θ. Therefore, the set distance d between the diffractive optical element 50 and the light combination assembly 102-1 can satisfy the following formula one:

[0067] According to formula one, the set distance d between the diffractive optical element 50 and the light combination assembly 102-1 can be determined according to the spot magnification N, the distance S1 between the two light emitting points on the light emitting surface of the red laser chip 101-1, and the divergence angle θ of the red laser. For example, the value range of N can be 1.2-4, S1 can be 100 μm, and S2 can be 0.5 mm. If the divergence angle θ of the red laser of the double light emitting points after exiting the light combination assembly 102-1 is taken as the initial light phase distribution, then the radial phase distribution of the laser of each light emitting point shown in FIG. 5 can be calculated by using algorithms such as GS algorithm, angular spectrum method, point source method, and optical design software such as Zemax and VirtualLab.

[0068] In some embodiments, the diffractive optical element 50 includes three sub-zones, which correspond to red laser, green laser and blue laser respectively. When the red laser chip 101-1 emits red laser with double light spots, the diffractive optical element 50 moves so that the red laser with double light spots can be incident to the corresponding sub-zone of the diffractive optical element 50 after passing through the light combining element 102. Similarly, when the green laser chip 101-2 emits green laser, the diffractive optical element 50 moves so that the green laser can also be incident to the corresponding sub-zone of the diffractive optical element 50 after passing through the light combining element 102. When the blue laser chip 101-3 emits blue laser, the diffractive optical element 50 moves so that the blue laser can also be incident to the corresponding sub-zone of the diffractive optical element 50 after passing through the light combining element 102.

[0069] The diffractive optical element 50 modulates the incident laser beam so that the collimated laser beam emitted by the diffractive optical element 50 irradiates the same position of the phase light modulation device 40, avoiding the problem of spot ghosting.

[0070] The change process of the red spot from the emission of the laser to the incidence of the phase light modulation device is described below. At position 601 in FIG. 6b, the spots formed by the red laser with double light spots in the optical path space are overlapped, as shown in FIG. 7a. After the red laser with double light spots propagates for a distance, at position 602 in FIG. 6b, the spots formed by the red laser with double light spots in the optical path space are separated, as shown in FIG. 7b. After the red laser with double light spots continues to irradiate the diffractive optical element 50, the corresponding sub-zone of the diffractive optical element 50 modulates the red laser with double light spots, which not only collimates the red laser with double light spots, but also shapes and homogenizes the red laser with double light spots. Thus, at position 603 in FIG. 6b, the spots formed by the red laser with double light spots in the optical path space are overlapped, as shown in FIG. 7c. Because the longer the optical path, the greater the divergence angle of the light beam, part of the light beam cannot accurately irradiate the diffractive optical element 50, thereby producing stray light. Therefore, the spot area at position 603 is smaller than that at position 601.

[0071] In some embodiments, as shown in FIG. 6b, the projection device can further include a collimating lens group 70 located between the emitted light of the diffractive optical element 50 and the incident light of the phase light modulation device 40. The collimating lens group 70 is used to collimate and focus the incident laser beam. After the collimating lens group 70 collimates and focuses the red laser passing through the diffractive optical element, at position 604 in FIG. 6b, the spot formed by the red laser in the optical path space is further reduced, as shown in FIG. 7d.

[0072] If the red laser of the double light spots emitted by the red laser chip 101-1 in FIG. 6b does not pass through the diffractive optical element 50 and directly irradiates the phase light modulation device 40, since the light spots formed by the double light spots of the red laser in the optical path space after the double light spots of the red laser propagate for a distance are separated, and the double light spots of the red laser do not pass through collimation, the divergence degree in the fast axis direction becomes larger, which causes the light spot formed by the double light spots of the red laser to exceed the effective area of the phase light modulation device 40. The light spot diagram is shown in FIG. 7e. Similarly, the green laser emitted by the green laser chip 101-2 and the blue laser emitted by the blue laser chip 101-3 do not pass through collimation, and the divergence degree in the fast axis direction becomes larger, which causes the light spots formed by the green laser and the blue laser to exceed the effective area of the phase light modulation device 40.

[0073] FIG. 8 shows a structural diagram of a projection device according to an embodiment of the present application.

[0074] As shown in FIG. 8, the projection device further includes a focusing lens group 80. The focusing lens group 80 is located between the light exit side of the phase light modulation device 40 and the light entrance side of the display element 201, and is configured to converge the incident laser beam.

[0075] In some embodiments, the focusing lens group 80 can include a first lens 801 and a second lens 802 arranged in sequence along the propagation direction of light, and a reflecting mirror 803 is further arranged between the first lens 801 and the second lens 802, and the reflecting mirror 803 receives the exit light of the first lens 801 and reflects it to the second lens 802.

[0076] The projection device can further include a light splitting prism 90 and a projection lens 91. The light splitting prism 90 is located between the focusing lens group 80 and the display element 201. The light splitting prism 90 is configured to reflect the exit light of the focusing lens group 80 to the display element 201, and transmit the light modulated by the display element 201 to the projection lens 91.

[0077] The present application can reduce the volume and complexity of the optical path in the projection device by arranging the diffractive optical element 50 between the laser light source 10 and the phase light modulation device 40.

[0078] FIG. 9 shows a structural diagram of a projection device according to another embodiment of the present application. The difference between the projection device shown in FIG. 9 and the projection device shown in FIG. 8 is that the specific structure of the light combining assembly 102 in the laser light source 10 is different.

[0079] As shown in FIG. 9, the light combination assembly 102 can include a second mirror 102-4, a first cylindrical lens 102-5, a first telescope group 102-6, a third dichroic plate 102-7, a third mirror 102-8, a second cylindrical lens 102-9, a second telescope group 102-10, a fourth dichroic plate 102-11, a fourth mirror 102-12, a third cylindrical lens 102-13, a third telescope group 102-14, and a fifth mirror 102-15.

[0080] The second mirror 102-4 is located between the light exit side of the red laser chip 101-1 and the light entrance side of the first cylindrical lens 102-5, and is used to reflect the red laser beam. The first cylindrical lens 102-5 is located between the light exit side of the second mirror 102-4 and the light entrance side of the first telescope group 102-6, and is used to perform stereoscopic imaging, correct astigmatism, and change the shape of the light beam for the incident red laser beam. The first telescope group 102-6 is located between the light exit side of the first cylindrical lens 102-5 and the light entrance side of the third dichroic plate 102-7, and is used to collimate and shrink the red laser beam. The third dichroic plate 102-7 is located between the light exit side of the first telescope group 102-6, the light exit side of the fourth dichroic plate 102-11, the light exit side of the fifth mirror 102-15, and the light entrance side of the phase light modulation device 40, and the third dichroic plate 102-7 is used to reflect the red laser beam, transmit the blue laser beam, and transmit the green laser beam.

[0081] The third mirror 102-8 is located between the light exit side of the green laser chip 101-2 and the light entrance side of the second cylindrical lens 102-9, and is used to reflect the green laser beam. The second cylindrical lens 102-9 is located between the light exit side of the third mirror 102-8 and the light entrance side of the second telescope group 102-10, and is used to perform stereoscopic imaging, correct astigmatism, and change the shape of the light beam for the incident green laser beam. The second telescope group 102-10 is located between the light exit side of the second cylindrical lens 102-9 and the light entrance side of the fourth dichroic plate 102-11, and is used to collimate and shrink the green laser beam. The fourth dichroic plate 102-11 is located between the light exit side of the second telescope group 102-10, the light exit side of the fifth mirror 102-15, and the direction away from the light entrance side of the third dichroic plate 102-7, and the fourth dichroic plate 102-11 is used to reflect the green laser beam and transmit the blue laser beam.

[0082] The fourth mirror 102-12 is located between the light exit side of the blue laser chip 101-3 and the light entrance side of the third cylindrical lens 102-13, and is configured to reflect the blue laser beam. The third cylindrical lens 102-13 is located between the light exit side of the fourth mirror 102-12 and the light entrance side of the third telescope group 102-14, and is configured to perform stereoscopic imaging, correct astigmatism, and change the shape of the blue laser beam. The third telescope group 102-14 is located between the light exit side of the third cylindrical lens 102-13 and the light entrance side of the fifth mirror 102-15, and is configured to collimate and shrink the blue laser beam. The fifth mirror 102-15 is located between the light exit side of the third telescope group 102-14 and the direction away from the light entrance side of the fourth dichroic plate 102-11, and is configured to reflect the blue laser beam.

[0083] The light path propagation directions between other devices in FIG. 9 can refer to the related descriptions in FIG. 8, which will not be repeated here. It should be noted that the structure of the laser light source 10 in FIGS. 8 and 9 is only illustrative, and other structures that can realize the function of the laser light source 10 also belong to the protection scope of the present application.

[0084] In some embodiments, the phase light modulation device 40 can be a reflective phase light modulation device or a transmissive phase light modulation device. FIG. 10 is a structural schematic diagram of the reflective phase light modulation device provided by the embodiments of the present application. FIG. 11 is a structural schematic diagram of the transmissive phase light modulation device provided by the embodiments of the present application.

[0085] As shown in FIG. 10, the reflective phase light modulation device can include a plurality of phase adjustment units 400 arranged in an array. Each phase adjustment unit 400 includes a position adjustment element 401 and a mirror 402 mounted on the position adjustment element. The position adjustment element 401 is configured to drive the mirror 402 to move in a direction perpendicular to the reflecting surface of the mirror, so as to change the height of the reflecting surface of the mirror, thereby changing the optical path of the incident light, and finally causing the incident light to produce a phase change. According to the principle of light diffraction, the intensity distribution of the incident light on the image to be displayed is changed, so that more light reaches the bright area of the image to be displayed, and less light reaches the dark area of the image to be displayed. Therefore, the gray difference of the image to be displayed can be enhanced, the contrast can be enhanced, and the intensity distribution of the laser beam emitted by the reflective phase light modulation device can be matched with the image to be displayed.

[0086] As shown in FIG. 11, the transmissive phase light modulation device can include a plurality of phase adjustment units 400 arranged in an array. Each phase adjustment unit 400 includes a position adjustment element 401 and a light-transmitting mirror 403 mounted on the position adjustment element. The position adjustment element 401 is configured to drive the light-transmitting mirror 403 to move in a direction perpendicular to the light-transmitting mirror.

[0087] In a specific implementation, each position adjusting element 401 can be driven independently to adjust the position of the light transmission lens 403. After the position of each light transmission lens 403 is determined, all the light transmission lenses 403 can be regarded as a lens with a specific surface shape. Then, the light rays can generate a phase change after being incident on the lens, thereby achieving phase modulation of the incident light rays.

[0088] The specific structure of the position adjusting element 401 can refer to the position adjusting element in the reflective phase light modulation device. It is worth noting that, considering that the transmissive phase light modulation device needs to make the incident light rays pass through, the phase adjusting element 401 needs to be as small as possible to avoid blocking the incident light rays, so as to ensure the light transmittance. In addition, the light transmission lens 403 can adopt a flat lens, and the material can be glass or plastic, which is not limited here.

[0089] In a specific implementation, the reflective phase light modulation device or the transmissive phase light modulation device can be selected according to the design structure of the projection device. The reflective phase light modulation device not only has the function of phase adjustment, but also can fold the light path by turning the light rays, which is beneficial to the miniaturization design of the projection device.

[0090] Here, only the structure of the reflective phase light modulation device and the transmissive phase light modulation device is illustrated by way of example. Other structures that can realize the function of the reflective phase light modulation device or the transmissive phase light modulation device also belong to the protection scope of the present application.

[0091] Based on the same inventive concept, the embodiments of the present application also provide a projection system. FIG. 12 is a structural schematic diagram of the projection system provided by the embodiments of the present application.

[0092] As shown in FIG. 12, the projection system includes a projection device 1 and a projection screen 2. The projection screen 2 is located on the light exit side of the projection device 1. The audience faces the projection screen 2. The projection device 1 emits projection light rays. The projection light rays are incident on the projection screen 2 and reflected to the position where the audience is located through the projection screen 2, so that the audience can watch the projection image.

[0093] The projection device 1 sets the diffractive optical element on the light exit side of the light combination assembly at a set distance from the light combination assembly. The diffractive optical element is provided with multiple partitions. Each partition corresponds to a color of laser. The diffractive optical element moves according to the color of the laser emitted by the laser light source. The laser light sources emit laser beams of different colors to the corresponding partitions of the diffractive optical element. Each partition collimates the incident laser beam of the corresponding color, so that the diffractive optical element collimates the laser beams of different colors emitted by the laser and irradiates the phase light modulation device according to different time sequences.

[0094] Even if the laser beam of the double emitting point is emitted by the laser, due to the diffraction optical element, the laser beams of different colors are processed in different areas. Therefore, the laser beam of the double emitting point can be shaped and homogenized in the area corresponding to the double emitting point. The laser beam of the double emitting point and the laser beam of other colors can be incident to the center of the spot formed by the phase light modulation device respectively, so as to solve the ghosting problem.

[0095] Although the preferred embodiments of the application have been described, those skilled in the art will be able to make additional changes and modifications to the embodiments once they have the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the application.

[0096] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A projection device, comprising: Laser light source, used for time-division multiplexing of laser colors; A diffractive optical element is located on the light-emitting side of the laser source; the diffractive optical element includes multiple partitions, each partition corresponding to a different color of laser light; the diffractive optical element moves when the laser source emits laser light, so that different colors of laser light emitted by the laser source are respectively incident on the corresponding partitions of the diffractive optical element; each partition of the diffractive optical element is used to collimate the incident laser beam of the corresponding color. A phase-modulated light device is located on the light-emitting side of the diffractive optical element; the phase-modulated light device is used to modulate the phase of the incident laser beam according to the image to be displayed; and The display element, located on the light-emitting side of the phase light modulator, is used to modulate the brightness of the incident laser beam according to the driving data of the image to be displayed to form a display image.

2. The projection device as described in claim 1, wherein, The laser source includes a laser chip array; the laser chip array includes multiple first laser chips, multiple second laser chips, and multiple third laser chips, wherein the laser emitted by the first laser chip, the second laser chip, and the third laser chip is of a different color. The diffractive optical element includes multiple partitions, which are divided into a first partition, a second partition, and a third partition; the first partition corresponds to the laser emitted by the first laser chip, the second partition corresponds to the laser emitted by the second laser chip, and the third partition corresponds to the laser emitted by the third laser chip.

3. The projection device as described in claim 2, wherein, The laser emitted by the first laser chip includes two light-emitting points. When the laser emitted by the two light-emitting points enters the first partition, it is two light spots that are separated by a set distance. When the laser passes through the first partition and enters the phase light modulation device, the two light spots overlap each other.

4. The projection device as described in claim 2, wherein, The light spot of the laser emitted from the first laser chip when it passes through the first partition and enters the phase light modulation device, the light spot of the laser emitted from the second laser chip when it passes through the second partition and enters the phase light modulation device, and the light spot of the laser emitted from the third laser chip when it passes through the third partition and enters the phase light modulation device coincide.

5. The projection device as described in claim 3, wherein, The set distance d between the diffractive optical element and the laser source satisfies: Wherein, N is the magnification factor of the laser beam after the propagation distance d from the two light-emitting points, θ is the divergence angle of the laser beam emitted from the two light-emitting points, and S1 is the distance between the two light-emitting points on the light-emitting surface of the first laser chip.

6. The projection device as described in any one of claims 1 to 5, wherein, The diffractive optical element has multiple sections arranged in a circle, and the diffractive optical element is also connected to a driving device, which is used to drive the diffractive optical element to rotate in a plane perpendicular to the laser emission direction of the laser source.

7. The projection device as described in claim 6, wherein, The diffractive optical element has multiple fan-shaped sections, and the sections of each fan shape are arranged sequentially around the rotation axis of the diffractive optical element.

8. The projection device according to any one of claims 1 to 7, wherein, Each section of the diffractive optical element includes multiple diffractive microstructures, which are one of the following: multi-step structure, subwavelength nanoantenna, or photonic sieve.

9. The projection device as described in any one of claims 1 to 8, wherein, The phase distribution of the diffractive microstructures in each partition of the diffractive optical element is different.

10. The projection device as claimed in claim 9, wherein, The radial surface height of the diffractive optical element satisfies: Where Zsag represents the radial surface elevation of the diffractive optical element, c represents the reciprocal of the radius of curvature, k represents the conic coefficient, r represents the radial position, and a1, a2, a3, and a4 represent the 2nd, 4th, 8th, and 16th order aspherical coefficients, respectively.

11. The projection device as claimed in claim 10, wherein, The phase of the diffractive optical element satisfies: in, λ represents the phase, n represents the refractive index of the diffractive optical element, and λ represents the wavelength of the incident laser.

12. The projection device as claimed in claim 11, wherein, The radial phase of each partition of the diffractive optical element satisfies: Where, d λ θ represents the area of ​​the laser spot incident on the partition of the diffractive optical element. λ λ represents the divergence angle of the laser beam incident on the partition, λ represents the wavelength of the laser beam incident on the partition, and r represents the radial position of the laser beam incident on the partition.

13. The projection device according to any one of claims 1 to 12, further comprising: The collimating lens group, located between the light-emitting side of the diffractive optical element and the light-incident side of the phase light modulation device, is used to collimate the incident laser beam.

14. The projection device as described in claims 1 to 13, further comprising: A focusing lens group, located between the light-emitting side of the phase light modulation device and the light-incident side of the display element, is used to converge the incident laser beam.

15. The projection device according to any one of claims 1 to 14, wherein, The laser source includes: Lasers used for time-division multiplexing of laser colors; A light combining component, located on the light-emitting side of the laser, is used to combine multiple colors of laser light emitted from the laser.

16. The projection device as claimed in claim 15, wherein, The light combining component includes: The first reflector is located on the light-emitting side of the first laser chip; The first dichroic filter is located on the light-emitting side of the second laser chip; and The second dichroic filter is located on the light-emitting side of the third laser chip; The first reflector is used to reflect the laser emitted from the first laser chip to the first dichroic filter; the first dichroic filter is used to reflect the laser emitted from the second laser chip and transmit the laser emitted from the first laser chip; the second dichroic filter is used to reflect the laser emitted from the third laser chip and transmit the laser emitted from both the first and second laser chips.

17. The projection device as claimed in claim 15, wherein, The light combining component includes multiple light combining elements, which are respectively located on the light-emitting side of the first laser chip, the second laser chip, and the third laser chip; The light combining component includes: a reflector, a cylindrical lens, a telescope assembly, and a light combining mirror arranged sequentially along the direction of laser propagation.

18. A projection system, comprising: A projection device, wherein the projection device is the projection device according to any one of claims 1 to 17; and The projection screen is located on the light-emitting side of the projection device.

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