Laser projection optical module and laser projection equipment

Abstract

The present invention discloses a laser projection optical module, including a housing, an actuator, an optical fiber and a relay lens group encapsulated in the housing; the two ends of the actuator are respectively a fixed end and a free end, the optical fiber is fixed on the actuator and one end exceeds the free end of the actuator to form an optical fiber cantilever; with the light emission direction of the laser projection optical module as the front, the relay lens group is encapsulated at the front end of the housing and is located on the light output path of the optical fiber; at the rear end of the housing, a vibration device is provided that can drive the entire laser projection optical module to vibrate. The present invention provides a brand-new laser projection optical module with a speckle elimination function. A laser projector or laser TV using the laser projection optical module can achieve a good display effect without a special screen, can effectively reduce the hardware cost of the laser projector or laser TV, and is conducive to the large-scale production of laser TVs.

Description

Technical Field

[0001] The present invention relates to the field of laser display, and in particular to a laser projection optical module and a laser projection device. Background Art

[0002] Laser display technology is a display technology that uses red, green and blue primary color lasers as light sources. As a new generation of display technology, it not only inherits all the advantages of digital display technology, but also has a color gamut coverage of up to 90% of the color space recognizable by the human eye. It can truly reproduce the richest and most gorgeous colors in the objective world and provide more shocking expressiveness. Therefore, it is considered to be a revolution in the display field.

[0003] However, due to the high coherence of laser light sources, when the laser as a light source is projected onto the screen, the interference between the scattered light beams will cause irregularly distributed bright and dark spots on the projection image plane, namely laser speckle. The presence of speckle seriously affects the imaging quality of the display screen, reduces the image resolution and contrast, and becomes an important obstacle to the development of laser projection display. Therefore, the influence of speckle noise must be reduced as much as possible in laser display design. Only by effectively suppressing speckle can laser display technology become the mainstream of the new generation display industry.

[0004] At present, various solutions have been proposed at home and abroad for the speckle problem, such as introducing a rotating diffuser, rotating optical elements, vibrating mirrors, random phase plates, etc. in the optical path; increasing the spectral line width of the light source; and using pulsed laser superposition.

[0005] Among the many speckle elimination schemes, a large-screen laser TV launched by Mitsubishi in the display market in 2007 has been successfully applied. The color reproduction range of the TV screen is twice as wide as that of the LCD panel. The speckle elimination scheme of this laser TV adopts the method of moving screen. Through the screen composed of two scatterers next to each other, one screen is fixed, and the other screen next to the fixed screen makes a small movement. In this way, due to the movement of the screen, the speckle in the displayed image is superimposed. Due to the persistence effect of the human eye, the observer cannot feel the speckle on the screen, that is, the speckle pattern is superimposed by rotating the screen in the plane to keep the screen in continuous motion, thereby reducing the influence of the speckle. Two screens are required in this system, which not only increases the cost but also affects the weight of the whole machine, and requires a large driving force to increase power consumption. In fact, it is not very practical. Moreover, in the moving screen speckle elimination method, the light is scattered on the moving screen and directly reaches the fixed screen. If the scattering angle of the scatterer is larger than the numerical aperture or aperture value of the lens in the light path, part of the light will be lost. In addition, it is necessary to consider issues such as the appearance, weight, reliability, life and noise-free of the TV. And with the development of large-screen TVs, the size of TV screens is getting larger and larger. The jitter screen solution is very difficult to design the screen structure while meeting the above requirements. It is precisely because of this that Mitsubishi's laser large-screen TV is expensive and can only go the high-end consumer route and cannot be mass-produced.

[0006] The lower-priced laser TVs currently on the market generally do not use three-color lasers, but monochromatic lasers or two-color lasers, which are excited into three colors by phosphors. Since the wide spectrum produced by the phosphor excitation itself has a very small speckle effect, and a rotating light-homogenizing sheet is usually used in devices with this structure to further eliminate the speckle, they do not need the jitter screen mentioned above, only an ordinary anti-glare screen is needed. The cost is relatively low, but the display effect is far inferior to that of a real three-color laser TV. In fact, the color gamut and contrast are much worse than those of a real three-color laser.

[0007] How to achieve speckle elimination in a low-cost manner has become a technical challenge that must be overcome in the field of laser display. Summary of the invention

[0008] The object of the present invention is to provide a laser projection optical module which can eliminate speckle in a low-cost manner.

[0009] In order to achieve the above-mentioned purpose of the invention, the present invention provides a laser projection optical module, including a shell, an actuator, an optical fiber and a relay lens group encapsulated in the shell; the two ends of the actuator are respectively a fixed end and a free end, the optical fiber is fixed on the actuator and one end exceeds the free end of the actuator to form a fiber cantilever; with the light emission direction of the laser projection optical module as the front, the relay lens group is encapsulated at the front end of the shell and is located on the light output path of the optical fiber; at the rear end of the shell, a vibration device that can drive the entire laser projection optical module to vibrate is provided.

[0010] Preferably, the vibration device is generally a motor or a vibration device made of one of a piezoelectric crystal, a magnetic field changing material, and a field-induced deformation material.

[0011] Preferably, the vibration device is a piezoelectric driver that stretches and contracts in the front-to-back direction. When the piezoelectric driver is working, it drives the laser projection optical module to vibrate in the front-to-back direction.

[0012] Preferably, the vibration frequency f of the vibration device is ≥30 Hz, and the vibration amplitude A is ≤100 μm.

[0013] Preferably, the vibration frequency f of the vibration device is in the range of 200 Hz ≥ f ≥ 30 Hz, and the vibration amplitude A is in the range of 15 μm ≤ A ≤ 100 μm.

[0014] Preferably, the actuator includes a first actuator part and a second actuator part, the first actuator part can drive the second actuator part to vibrate in a first direction, the second actuator part can vibrate in a second direction, and the optical fiber cantilever is finally driven to sweep in a composite direction of the first direction and the second direction.

[0015] Preferably, the second actuating portion is a piezoelectric driver.

[0016] Preferably, the first actuating part is a motor or a vibration device made of one of a piezoelectric crystal, a magnetic field changing material, and a field-induced deformation material.

[0017] Preferably, a laser light source and a beam combiner are also encapsulated in the housing, and the light beams generated by the laser light source are combined by the beam combiner and then coupled into the optical fiber.

[0018] Preferably, the laser light source includes at least three-color laser light sources of R, G, and B.

[0019] Preferably, the internal components are encapsulated in a vacuum manner in the housing.

[0020] Correspondingly, the present invention also provides a laser projection device, which includes at least one group of any one of the above-mentioned laser projection optical modules.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a new laser projection optical module with a speckle elimination function. A laser projector or laser TV using the laser projection optical module can achieve a good display effect without the need for a special screen, which can effectively reduce the hardware cost of the laser projector or laser TV and is conducive to the large-scale production of laser TVs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor:

[0024] Figure 1 This is a schematic structural diagram of a laser projection optical module according to a first embodiment of the present invention;

[0025] Figure 2 This is another structural schematic diagram of the laser projection optical module according to the first embodiment of the present invention;

[0026] Figure 3 yes Figure 1 Schematic diagram of the structure of the laser projection optical module with an external laser light source;

[0027] Figure 4 This is a structural schematic diagram of a laser projection optical module according to a second embodiment of the present invention;

[0028] Figure 5 This is a structural schematic diagram of a laser projection optical module according to a third embodiment of the present invention;

[0029] Figure 6 yes Figure 5 Schematic diagram of the structure of the laser projection optical module with an external laser light source;

[0030] Figure 7 This is a schematic structural diagram of a laser projection optical module according to a fourth embodiment of the present invention;

[0031] Figure 8 Schematic diagram of the structure of the actuator in the embodiment of the present invention Figure 1 ;

[0032] Fig. 9 Schematic diagram of the structure of the actuator in the embodiment of the present invention Figure 2 ;

[0033] Fig.10 Yes Figure 1 A schematic diagram of splicing multiple laser projection optical modules;

[0034] Fig.11 Yes Figure 4 A schematic diagram of splicing multiple laser projection optical modules;

[0035] Fig.12 Yes Figure 5 A schematic diagram of splicing multiple laser projection optical modules;

[0036] Fig.13Schematic diagram of a laser projection device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The “laser projection optical module” in the embodiment of the present invention may also be referred to as a “fiber optic scanner”.

[0039] Embodiment 1:

[0040] See also Figures 1 to 3 The laser projection optical module of this embodiment includes an outer shell 101, an actuator 102, an optical fiber and a relay lens group 105 encapsulated in the outer shell 101; the two ends of the actuator 102 are a fixed end and a free end respectively. Figure 1 In the example, the fixed end of the brake 102 is fixed to the inner side of the rear end of the housing 101 through a fixing bracket 107, the optical fiber is fixed to the actuator and one end thereof extends beyond the free end of the actuator to form an optical fiber cantilever 104, and the other end 103 of the optical fiber extends beyond the rear end of the housing as the light input end; the light emitting direction of the laser projection optical module is taken as the front end, and the end opposite to the light emitting end is taken as the rear end, that is, Figure 1 In the figure, the arrow is in the forward direction, the relay lens group 105 is encapsulated at the front end of the housing 101 and is located on the light path of the optical fiber; at the rear end of the housing 101, a vibration device 106 is provided to drive the entire laser projection optical module to vibrate. The relay lens group in the embodiment of the present invention can be designed to have one or more functions of collimation, imaging, amplification, light uniformity, focusing, etc. according to actual implementation requirements. Figure 1 In the example, the vibration device 106 is arranged on the outer side of the rear end of the housing 101. In the specific implementation, the vibration device 106 can also be arranged according to Figure 2 The arrangement shown is implemented in a manner that a portion of the vibration device 106 extends beyond the rear end and a portion is embedded in the rear end of the shell. The applicant does not limit the specific arrangement of the vibration device, as long as the vibration device 106 can drive the entire laser projection optical module to vibrate.

[0041] In this embodiment, the vibration device 106 and the brake 102 can be separate devices or designed as an integral structure. When the vibration device 106 and the brake 102 are integrally formed, in the embodiment of the present invention, when the housing 101 is encapsulated, the vibration device 106 is partially exposed outside the rear end of the housing 101.

[0042] The other end 103 of the optical fiber extends beyond the rear end of the housing as a light input end, and when in use, can be connected to the light output optical fiber of other optical devices such as a laser light source, such as Figure 3 ,yes Figure 1 Schematic diagram of an external laser light source of a laser projection optical module. The laser light source 201 includes three-color lasers of R, G, and B. The three-color lasers are combined by a beam combiner 301 and input Figure 1 In the laser projection optical module, the output optical fiber of the combiner 301 is connected to the end of the optical fiber 103. The connection between the optical fibers can be operated by a fiber fusion splicer. The vibration device 106 preferably vibrates in the forward and backward directions indicated by the arrows.

[0043] Speckle is essentially a redistribution of energy caused by interference. The interference term is a quantity that changes over a time period. What the human eye perceives is the integration of the interference term within the human eye integration time. In the embodiment of the present invention, since the vibration device 106 drives the entire laser projection optical module to vibrate, the speckle pattern at a certain moment cannot be accurately distinguished due to the visual persistence effect of the human eye. When the laser projection optical module vibrates, the specific spatial energy distribution caused by the speckle pattern received by the human eye will produce a homogenization effect due to this vibration change, ultimately achieving the purpose of reducing or even eliminating the speckle.

[0044] Embodiment 2:

[0045] See also Figure 4 The laser projection optical module in this embodiment is Figures 1 to 3 The difference between the laser projection optical module in is: Figure 4 The embodiment encapsulates the laser light source 201 and the beam combiner 301 in the housing 101, and the actuator 102 is fixed to the middle of the housing through the fixing bracket 107. The laser light source 201 includes at least three-color laser light sources of R, G, and B. The light beam generated by the laser light source 201 is coupled into the optical fiber after being combined by the beam combiner 301, and is emitted by the optical fiber cantilever 104. The vibration device 106 also drives the entire laser projection optical module to vibrate. Preferably, the laser light source includes at least three-color laser light sources of R, G, and B.

[0046] Embodiment three:

[0047] See also Figure 5 and Figure 6 The laser projection optical module shown in this embodiment includes a housing 101, a vibration device 106, an actuator 102, an optical fiber and a relay lens group 105 encapsulated in the housing 101; with the light emitting direction of the laser projection optical module as the front, the end opposite to the light emitting end as the rear end, the vibration device 106 is fixed to the inner side of the rear end of the housing, Fig. 9In the example, the vibration device 106 is fixed to the inner side of the rear end of the housing 101 through a fixed bracket 107, the two ends of the actuator 102 are respectively a fixed end and a free end, the fixed end is fixed to the vibration device 106, the optical fiber is fixed to the actuator 102 and one end extends beyond the free end of the actuator 102 to form an optical fiber cantilever 104, and the other end of the optical fiber extends beyond the rear end of the housing as a light input end, and the relay lens group 105 is a zoom lens group or a telephoto depth lens group, which is encapsulated at the front end of the housing and is located on the light output path of the optical fiber.

[0048] Figure 6 for Figure 5 Schematic diagram of the structure of the laser projection optical module with external laser light source and beam combiner.

[0049] The difference between this embodiment and the first embodiment is that in the first embodiment, the vibration device 106 drives the entire laser projection optical module to vibrate, while in the present embodiment, due to the different installation positions, the vibration device 106 directly drives the actuator 102 to vibrate, thereby indirectly driving the fiber cantilever 104 to vibrate. Since the vibration subject has changed, in the present embodiment, the relay lens group 105 must be a zoom lens group or a long focal depth lens group, while in the first and second embodiments, the relay lens group may not have a zoom function. When the relay lens group 105 in the embodiment of the present invention adopts a zoom lens, the zoom control is used so that no matter how the distance between the light-emitting end of the scanning optical fiber and the relay lens group changes, it can always be focused on the screen. Since the relay lens group adopts a long focal depth lens, when the distance between the image plane scanned by the scanning optical fiber and the relay lens group changes slightly, the image on the screen is less affected.

[0050] Embodiment 4:

[0051] See also Figure 7 The laser projection optical module in this embodiment is Figure 5 and Figure 6 The difference between the laser projection optical module in is: Figure 7 The embodiment encapsulates the laser light source 201 and the beam combiner 301 into the housing 101, and the actuator 102 is fixed to the middle of the housing through the fixing bracket 107. The laser light source 201 includes at least three-color laser light sources of R, G, and B. Figure 5 The embodiment is consistent, that is, the vibration device 106 also only drives the actuator 102 and the optical fiber cantilever 104 fixed thereon to vibrate, and the relay lens group 105 must be a zoom lens group or a telephoto lens group.

[0052] In the third and fourth embodiments, the vibration device 106 and the brake 102 may be separate components or may be designed as an integrally formed structure.

[0053] Combined with the above Figure 1-7The different structures of four embodiments of the laser projection optical module are described, and the common parts of the above four embodiments will be described below.

[0054] In all the above embodiments, the vibration device 106 can be a vibration motor or a vibration device made of piezoelectric crystals, magnetic field change materials, field-induced deformation materials, electrostrictive materials and other materials, which can achieve vibration in one or more directions through motor drive, electrostriction, magnetic drive and other methods, thereby driving the entire laser projection optical module to vibrate.

[0055] In the preferred embodiment of all the above embodiments, the vibration device 106 preferably adopts a piezoelectric driver that stretches in the front-to-back direction. When the piezoelectric driver is working, it drives the laser projection optical module to vibrate in the front-to-back direction, that is, the piezoelectric driver works in the "d33 mode". The "d33 mode" means that when the external electric field E is in the same direction as the polarization intensity P, the thickness (t) direction is elongated; when E / P is reversed, the thickness (t) direction is shortened. The vibration frequency of the vibration device 106 is preferably higher than the vibration frequency defined by the upper limit of the moving speed of the object recognizable by the human eye. It is well known that the human eye visually recognizes objects with a speed range equal to or less than 30Hz. Therefore, the vibration frequency of the vibration device 106 is preferably greater than or equal to 30Hz. In order to reduce the design volume and power consumption of the laser projection optical module, the vibration amplitude of the vibration device 106 is preferably controlled within 100μm. More preferably, the vibration frequency f of the vibration device in the embodiment of the present invention ranges from: 200Hz≥f≥30Hz, and the vibration amplitude A ranges from: 15μm≤A≤100μm.

[0056] The brake 102 in all the above embodiments may be a spiral scanning actuator or a raster scanning actuator, and the present invention does not impose any limitation on the actuator structure.

[0057] Since the image source in the field of laser projection imaging is generally a rectangular area, the spiral scanning method has many disadvantages, such as: it is not easy to match with the image source, the pixel utilization rate is not high, etc. Therefore, the embodiment of the present invention preferably adopts a grid scanning actuator, specifically: the actuator includes a first actuator and a second actuator, the first actuator can drive the second actuator to vibrate in a first direction, the second actuator can vibrate in a second direction, and the optical fiber cantilever is finally driven to sweep in the composite direction of the first direction and the second direction. Preferably, the first direction and the second direction are perpendicular, one is scanning in the X direction, and the other is scanning in the Y direction. In addition, the first actuator and the second actuator can be driven by piezoelectric drive, motor drive or magnetic drive, etc., respectively, without limitation. For example, the first actuator and the second actuator can be made of a motor or one of a piezoelectric crystal, a magnetic field change material, and a field-induced deformation material. The first actuator and the second actuator can be separate components, and the two are combined together by bonding, clamping or connecting parts; the first actuator and the second actuator can also be an integrally formed structure, without limitation. In order to make the actuator structure easier to understand, the following is a schematic diagram of the structure of the actuator. Figure 8 and Fig. 9 For example. Figure 8 and Fig. 9 In the figure, reference numeral 1021 denotes a first actuating portion, reference numeral 1022 denotes a second actuating portion, reference numeral 104 denotes an optical fiber cantilever, reference numeral 1023 denotes a connecting portion or an isolating portion, Figure 8 In the embodiment, the first actuating part and the second actuating part are designed to be split and snap-fitted. Fig. 9 The first actuating portion and the second actuating portion are designed to be integrally formed.

[0058] In the embodiment of the present invention, since the optical fiber itself is very light, the size of the actuator that drives the optical fiber scanning can be made very small, so the size and weight of the entire laser projection optical module can be made very small. The vibration device drives the entire laser projection optical module to vibrate, and the required power consumption can also be very low.

[0059] In all the above embodiments, the actuator, optical fiber, relay mirror assembly and other internal components are preferably encapsulated in a vacuum manner in the housing.

[0060] In laser projection, multiple fiber scanners (laser projection optical modules) are often required for splicing. When working, the vibration device of each fiber scanner can vibrate in one or more directions synchronously or asynchronously (i.e., the same frequency or different frequencies, the same amplitude or different amplitudes) to achieve the function of eliminating speckles. Fig.10 It indicates that Figure 1 Schematic diagram of splicing multiple laser projection optical modules, wherein 400 is a common fixing part of each fiber scanner, and the vibration device 106 of each fiber scanner is fixed on the fixing part 400. Fig.11 It indicates that Figure 4Schematic diagram of multiple laser projection optical modules spliced ​​together. Fig.12 It indicates that Figure 5 Schematic diagram of splicing multiple laser projection optical modules.

[0061] Compared with the laser projection optical modules in the second and fourth embodiments, the laser projection optical modules in the first and third embodiments have better heat dissipation because the laser light source is not encapsulated inside the module. At the same time, since the laser projection optical module retains the most streamlined structure, the volume and weight are small, the driving force requirements for the vibration device are low, and it is easy to achieve mass production and ensure the effect. Of course, when the relay lens group in the third and fourth embodiments uses a zoom lens group, the control difficulty is increased compared with the first and second embodiments. Therefore, the first embodiment is the best embodiment of the present invention.

[0062] The laser projection optical module of the embodiment of the present invention is applicable to laser projection equipment. In the laser projection equipment, one or more sets of laser projection optical modules of the embodiment of the present invention can be used. Fig.13 As shown, it is a schematic diagram of a laser projection device. The laser projection optical module 100 of the present invention is adopted in the optical module of the laser projector 500. Since the laser projection optical module 100 of the present invention has the function of eliminating speckles, the projection screen 600 can be an ordinary anti-light screen or even an ordinary projector screen.

[0063] The present invention provides a new laser projection optical module with a speckle elimination function. A laser projector or laser TV using the laser projection optical module can achieve a good display effect without the need for a special screen, which can effectively reduce the hardware cost of the laser projector or laser TV and is conducive to the large-scale production and popularization of laser TVs.

[0064] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0065] Any feature disclosed in this specification (including any additional claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0066] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A laser projection optical module for eliminating speckle, characterized in that: It includes a shell, an actuator, an optical fiber and a relay lens group encapsulated in the shell; the two ends of the actuator are respectively a fixed end and a free end, the optical fiber is fixed on the actuator and one end exceeds the free end of the actuator to form an optical fiber cantilever; with the light emitting direction of the laser projection optical module as the front, the relay lens group is encapsulated at the front end of the shell and is located on the light emitting path of the optical fiber; at the rear end of the shell, a vibration device is provided which can drive the entire laser projection optical module to vibrate.

2. The laser projection optical module for eliminating speckles according to claim 1, characterized in that: The vibration device is a motor or a vibration device made of one of a piezoelectric crystal, a magnetic field variation material, and a field-induced deformation material.

3. The laser projection optical module for eliminating speckles according to claim 1, characterized in that: The vibration device is a piezoelectric driver that stretches and contracts along the front-to-back direction. When the piezoelectric driver is working, it drives the laser projection optical module to vibrate along the front-to-back direction.

4. The laser projection optical module for eliminating speckles according to claim 2 or 3, characterized in that: The vibration frequency f of the vibration device is ≥30 Hz, and the vibration amplitude A is ≤100 μm.

5. The laser projection optical module according to claim 4, characterized in that: The vibration frequency f of the vibration device is in the range of 200 Hz ≥ f ≥ 30 Hz, and the vibration amplitude A is in the range of 15 μm ≤ A ≤ 100 μm.

6. The laser projection optical module for eliminating speckles according to any one of claims 1, 2, 3, and 5, characterized in that: The actuator comprises a first actuating part and a second actuating part, wherein the first actuating part can drive the second actuating part to vibrate in a first direction, and the second actuating part can vibrate in a second direction, and the optical fiber cantilever is finally driven to sweep in a composite direction of the first direction and the second direction.

7. The laser projection optical module for eliminating speckles according to claim 6, characterized in that: The second actuating portion is a piezoelectric driver.

8. The laser projection optical module for eliminating speckles according to claim 7, characterized in that: The first actuating part is a motor or a vibration device made of one of a piezoelectric crystal, a magnetic field variation material, and a field-induced deformation material.

9. The laser projection optical module for eliminating speckles according to any one of claims 1, 2, 3, 5, 7, and 8, characterized in that: A laser light source and a beam combiner are also encapsulated in the housing. The light beams generated by the laser light source are combined by the beam combiner and then coupled into the optical fiber.

10. The laser projection optical module for eliminating speckles according to claim 9, characterized in that: The laser light source includes at least three-color laser light sources of R, G, and B.

11. The laser projection optical module for eliminating speckles according to any one of claims 1, 2, 3, 5, 7, 8, and 10, characterized in that: The internal components are sealed in a vacuum manner in the shell.

12. A laser projection device for eliminating speckles, characterized in that: The laser projection device comprises at least one set of laser projection optical modules as described in any one of claims 1 to 11.

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