CN110928123A - Laser array, laser light source and laser projection equipment - Google Patents
Laser array, laser light source and laser projection equipment Download PDFInfo
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- CN110928123A CN110928123A CN201811118508.6A CN201811118508A CN110928123A CN 110928123 A CN110928123 A CN 110928123A CN 201811118508 A CN201811118508 A CN 201811118508A CN 110928123 A CN110928123 A CN 110928123A
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/20—Lamp housings
- G03B21/2006—Lamp housings characterised by the light source
- G03B21/2033—LED or laser light sources
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/48—Laser speckle optics
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/20—Lamp housings
- G03B21/2006—Lamp housings characterised by the light source
- G03B21/2013—Plural light sources
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
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Abstract
The invention discloses a laser array, a laser light source and laser projection equipment, and belongs to the technical field of laser display. The laser array comprises a light emitting part, a light transmitting part and a light receiving part, wherein the light emitting part emits laser beams, and the light transmitting part is arranged along the light emitting direction of the light emitting part and is used for transmitting the laser beams; the light transmission part comprises a first light transmission area and a second light transmission area, and the polarization states of laser beams emitted by the light emitting part after penetrating through the first light transmission area and the second light transmission area are linearly polarized light and circularly polarized light respectively, so that a plurality of polarization state mixed laser beams are formed, the coherence of the laser beams emitted by the laser array can be reduced, and speckle elimination is facilitated.
Description
Technical Field
The invention relates to the technical field of laser display, in particular to a laser array, a laser light source and laser projection equipment related to the laser array.
Background
In recent years, lasers have been increasingly used as light sources in the field of projection display technology. However, due to the high coherence of the laser light, the speckle effect is inevitably generated. Speckle is that when a coherent light source irradiates a rough object, scattered light has the same wavelength and a constant phase, so that interference occurs in space, some parts in the space interfere constructively, some parts interfere destructively, and finally granular light and dark spots appear at a display end, so that the quality of a projected image is reduced.
Fig. 1 shows a schematic structural diagram of a laser array in the prior art, which includes a metal support 01, the metal support 01 is formed with a plurality of grooves 02, each groove 02 accommodates a laser light emitting chip 012 and a collimating lens 011, and the laser light emitting chip 012 and the collimating lens 011 shown in fig. 1 are packaged together and accommodated in the groove 02. Laser beams emitted by the laser array enter a light path, are irradiated to a light modulation device in the optical machine through convergence, shaping and the like, and are emitted after modulation. When the laser array is used as a light source, an anti-speckle element is required to be arranged in the light path to reduce the speckle effect.
In order to reduce the speckle effect of laser light due to the characteristics of the laser, the related art includes using a rotating diffuser or an oscillating diffuser in the laser light transmission path, or increasing the spatial phase of the laser light by providing a diffuser to reduce speckle by destroying the interference condition of constant phase. The method is characterized in that the influence of speckles is weakened by vibrating an optical fiber, a screen and the like, but the method is limited by application scenes and cost, for example, the optical fiber is usually matched with a coupling lens for use, and a good speckle eliminating effect is achieved, the size is usually large, the method is not beneficial to household use, a driving circuit needs to be additionally arranged on the screen when the screen is vibrated, and along with the increase of the size of the screen, the difficulty and the cost brought to driving control are also high.
The existing commonly used speckle elimination scheme is that a speckle elimination element is added in a transmission light path based on laser, so that the complexity of the light path is increased, and the speckle elimination effect is related to the light processing efficiency of the light path design, so that the problem of eliminating speckles of the whole optical system is greatly restricted 1.
Disclosure of Invention
In order to solve the speckle technical problem of laser projection display, the invention provides a laser array which is applied to a laser light source, can emit laser beams with low coherence and is beneficial to reducing the speckle effect during laser projection display.
In order to achieve the purpose, the invention adopts the following technical scheme:
the present invention provides a laser array comprising:
a light emitting section that emits a laser beam, and is provided with a light transmitting section along a light emitting direction of the light emitting section, for transmitting the laser beam; the light-transmitting part comprises a first light-transmitting area and a second light-transmitting area, and the first light-transmitting area and the second light-transmitting area are arranged so that light beams transmitted through the two areas from the light-emitting part have polarization states of linear polarization and circular polarization respectively;
preferably, the light emitting portion includes at least a plurality of light emitting chips, a metal substrate on which the plurality of light emitting chips are disposed; the metal substrate of the light-transmitting part is matched to form a sealed space; the light-emitting chips are all arranged in the sealed space;
preferably, the light-transmitting part comprises a window support, and the first light-transmitting region and the second light-transmitting region respectively comprise a plurality of first light-transmitting units, a plurality of second light-transmitting units, and the plurality of first light-transmitting units and the second light-transmitting units are adhered to the window support; the curvature of the first light-transmitting unit and the curvature of the second light-transmitting unit are zero; or the light transmission part comprises a light transmission glass plate, and the light transmission glass plate is coated with a film in regions to form a first light transmission region and a second light transmission region;
preferably, the first light transmission unit and the second light transmission unit are arranged at intervals in rows or columns.
Or each first light-transmitting unit and each second light-transmitting unit are adjacently arranged;
preferably, one of the first light-transmitting area and the second light-transmitting area is flat glass or a diffusion plate, and the other is a quarter-wave plate;
preferably, the LED lamp further comprises a collimating part, wherein the collimating part comprises a plurality of collimating lens units, and the number of the collimating lens units is consistent with that of the light emitting chips;
preferably, the light emitting chips are arranged in a row-column array;
preferably, the color of the light beam emitted by the light emitting chip is one of blue, green and red;
or the color of the light beam emitted by the light-emitting chip is any two of blue, green and red;
or the light emitting chip emits blue laser, red laser and green laser.
The invention also provides a laser light source which comprises the laser array.
The invention also provides laser projection equipment comprising the laser light source.
The first light transmission area and the second light transmission area of the light transmission part have different transmission processing for the laser beams, one area can allow the laser to emit according to the original polarization state, the other area can change the polarization state of the laser beams, such as changing the polarization state from linearly polarized light to circularly polarized light, so that mixed beams of the laser beams in different polarization states can be formed after the light emitting chip of the laser transmits the light transmission part, the laser beams in different polarization states are mixed and output, the coherence among the laser beams is reduced, the probability of generating independent speckle patterns is increased, the laser beams with low coherence can be provided, and the speckle effect during rear-end laser projection display is favorably reduced.
The laser light source and the laser projection equipment provided by the invention also have the beneficial technical effects, the low-coherence laser beam can reduce or simplify the use of speckle elimination components in the optical path, the complexity of the whole optical path structure is favorably reduced, and the miniaturization of the laser light source and the laser projection equipment is favorably realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a block diagram of a prior art laser array;
FIG. 2A is a schematic cross-sectional view of an embodiment of a laser array;
FIG. 2B is a schematic cross-sectional view of another laser array in an embodiment of the invention;
FIG. 3A is a schematic cross-sectional view of the light emitting portion of the laser array of FIG. 2A;
FIG. 3B is a schematic front view of a light-transmitting portion of the laser array of FIG. 2A;
FIGS. 4A,4B,4C, and 4D are schematic diagrams of the arrangement of the light-transmitting portions in the embodiment of the present invention, respectively;
FIG. 5 is a schematic diagram of an assembly structure of a laser array according to an embodiment of the present invention;
fig. 6 is a schematic diagram illustrating an arrangement of the collimating parts according to the embodiment of the present invention.
FIG. 7A is a schematic diagram of a front view of a laser array in an embodiment of the invention;
FIG. 7B is a schematic diagram of a front view of a laser array in an embodiment of the invention;
FIG. 8 is a schematic diagram of a laser source according to an embodiment of the present invention;
FIG. 9 is a schematic diagram illustrating an architecture of a laser projection apparatus according to an embodiment of the present invention;
FIG. 10 is a diagram illustrating a change in polarization state of a laser beam according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any creative effort, shall fall within the protection scope of the present invention.
The first embodiment,
Referring to fig. 2A, fig. 2A is a schematic cross-sectional view of a laser array according to an embodiment of the present invention, the laser array of the present embodiment includes a light emitting part 021 for emitting a laser beam, and a light transmitting part 022 for transmitting the laser beam is disposed along a light emitting direction of the light emitting part 021. Specifically, referring to fig. 3A, the light emitting part 021 includes a light emitting chip 0211, and a metal substrate 0212, and the light emitting chip is connectively fixed to the metal substrate 0212. The light emitting chip 0211 is electrically driven to emit a laser beam, which may be linearly polarized light, as shown in the left part of fig. 10.
The light-transmitting portion 022 includes a first light-transmitting region, a second light-transmitting region, and the first light-transmitting region and the second light-transmitting region are disposed so that light beams transmitted through the light-transmitting portion 021 have polarization states of linear polarization and circular polarization, respectively.
Referring to fig. 2A, the light-transmitting portion 22 is a light-transmitting layer structure covering the light-emitting side of the laser beam of the light-emitting portion 021, and in an embodiment, referring to fig. 3B, the light-transmitting portion 022 includes a window support 0221, and a plurality of hollow windows 0222 are formed on the window support 0221 for adhering and accommodating a plurality of light-transmitting units. In a specific implementation, the light transmitting unit is a light transmitting component with zero curvature and is used for transmitting the laser beam without generating a convergent collimation effect on the laser beam.
Specifically, a plurality of light-transmitting units (not shown in the figure) may be cured and adhered to the window frame 0221 by UV glass paste, and the plurality of light-transmitting units are divided into two regions according to whether the polarization state of the transmitted laser light is changed or not: a first light-transmitting region and a second light-transmitting region. The polarization state of the laser beam emitted by the light emitting part 021 after passing through the first light transmission region is different from that of the laser beam emitted by the second light transmission region, for example, as shown in fig. 10, the original linear polarization is changed into circular polarization, and the polarization state changes.
In one embodiment, one of the first and second light-transmitting regions is made of flat glass, and the other is made of quarter-wave plate, so that after the laser beam is transmitted through the first and second light-transmitting regions, one of the light beams still keeps the original linearly polarized light characteristic and has a light vector vibration direction, and the other light beam passes through the quarter wave plate, because the linearly polarized light vertically enters the quarter-wave plate, and the polarization direction of the linearly polarized light forms an angle of 45 degrees with the optical axis of the wave plate, circularly polarized light is generated as shown in fig. 10, such that the circularly polarized light has a plurality of light vector vibration directions, there are a plurality of different polarization states from the original linearly polarized light, the coherence of the light beams having different polarization states with each other is reduced, the laser array can emit low-coherence laser beams, and is beneficial to reducing the speckle effect during rear-end laser projection display.
In one embodiment, a plurality of flat pieces of glass and quarter-wave plate elements are arranged according to the number of panes contained in the first light transmission area and the second light transmission area, and are respectively adhered to the window of the light transmission part window support and are opposite to the emergent light beam of each laser light emitting chip, and the light transmission part is of a window-grid-shaped light transmission structure.
In another embodiment, the light-transmitting portion is an integral light-transmitting structure, such as a light-transmitting glass plate, and the transmission characteristics of different regions are realized by coating the film in different regions, such as the change of polarization state can be realized by partially coating the film, so as to form the first light-transmitting region and the second light-transmitting region. The position of the specific coating can be determined according to the requirement of changing the polarization state of the laser beam.
And, in another embodiment, the non-polarization conversion element can be made of a diffusion sheet material in addition to flat glass, so that the laser beam can be homogenized while being transmitted through.
In an embodiment, a plurality of light transmitting units are bonded to the window 0221 to form a light transmitting layer structure in a window grid shape, as shown in a schematic view of a laser array package structure shown in fig. 5, a light transmitting portion of the light transmitting layer structure covers a light emitting direction of the light emitting chip, and an edge portion of the light transmitting layer structure may be fixed to the metal substrate by welding or gluing, specifically, the window support and the metal substrate may be fixed by resistance welding to form a sealed space, and the light emitting chips are all contained in the sealed space to protect the light emitting chips and play a role in dust prevention and isolation. Optionally, the sealed space is filled with nitrogen, so that oxidation of the light emitting chip can be further prevented, and the performance and the service life of the laser are improved.
The first light transmission region and the second light transmission region of the light transmission part respectively comprise a plurality of first light transmission units and second light transmission units, and the first light transmission units and the second light transmission units are all bonded in a window 0222 formed in a window support 0221. In one embodiment, in the laser array, the number of the plurality of light emitting chips is equal to the sum of the number of the plurality of first light transmitting units and the number of the plurality of second light transmitting units, that is, each light emitting chip of the laser emits a light beam corresponding to one light transmitting unit and transmits through the light transmitting unit. For example, when the laser array includes 20 lasers, that is, 20 light emitting chips, the sum of the number of the first light transmitting units and the number of the second light transmitting units is also 20, and each first light transmitting unit or each second light transmitting unit faces the light emitting direction of a certain light emitting chip.
Of course, light beams emitted by several laser light emitting chips may be incident on the light transmitting units, that is, the division of the first light transmitting unit and the second light transmitting unit is not consistent with the number of the laser light emitting chips, for example, when the laser array includes 20 light emitting chips, the number of the first light transmitting units may be set to 5, and the number of the second light transmitting units is set to 5, so that 10 light transmitting units are provided, and laser beams emitted by every two laser light emitting chips are incident on one light transmitting unit.
When the total number of the light-transmitting units is consistent with the total number of the light-emitting chips of the laser, a plurality of laser beams with different polarization states can be divided more finely, so that the laser beams are mixed more uniformly, and the coherence is reduced more favorably.
Next, the arrangement structure of the light transmitting units of the light transmitting part will be described in detail with reference to examples given in fig. 4A,4B,4C, and 4D. For simplicity, the laser array includes 20 laser light emitting chips, and the description is made in an array arrangement manner of 4 × 5.
As illustrated in fig. 4A, the light-transmitting portion 22 includes a plurality of first light-transmitting units 0222a, which are indicated by filled vertical lines, and a plurality of light-transmitting units 0222a constitute a first light-transmitting region, and a plurality of second light-transmitting units 0222b, which are indicated by blank squares and a plurality of light-transmitting units 0222b constitute a second light-transmitting region. In the example of fig. 4A, the laser light emitting chips (not shown) are arranged in an array to emit linearly polarized light, wherein exemplarily, the first light transmitting unit 0222a is a quarter wave plate, the second light transmitting unit 0222b is flat glass, the polarization state of the laser beams emitted by the light emitting part is changed from linear polarization to circular polarization after the laser beams emitted by the light emitting part penetrate through the first light transmitting area composed of the first light transmitting units 0222a, and the polarization state of the laser beams emitted by the light emitting part is still linearly polarized light after the laser beams emitted by the light emitting part penetrate through the second light transmitting area composed of the second light transmitting units 0222b because the flat glass does not change the polarization state of the laser beams, i.e., the polarization state of the laser beams emitted by the light emitting part is different after the laser beams penetrate through the first light transmitting area and the second light transmitting area.
Wherein the flat glass and the quarter-wave plate may be the same size. The thickness of the flat glass or the quarter-wave plate can be selected to be between 0.5mm and 2mm, for example, about 0.7 mm.
Taking the arrangement shown in fig. 4A as an example, the first light-transmitting units and the second light-transmitting units may be arranged in rows at intervals, the first light-transmitting area includes two rows of first light-transmitting units, the second light-transmitting area includes two rows of second light-transmitting units, the laser beam still maintains the original polarization state after transmitting through the first light-transmitting area, for example, is linearly polarized light, and after transmitting through the second light-transmitting area, the polarization state is converted from the original linearly polarized light to circularly polarized light, the linearly polarized light and the circularly polarized light are arranged at intervals in the laser beam emitted from the laser array, and are mixed light of the linearly polarized light and the circularly polarized light, and the light beams with different polarization states are emitted at the same time, which is beneficial to reducing coherence.
In practical application, preferably, when the number of the arranged rows of the laser array is even, the first light-transmitting unit and the second light-transmitting unit are arranged at intervals, so that the light quantities of the outgoing linearly polarized light and the circularly polarized light are equivalent, and the effect of decoherence is better, because according to the definition of speckle contrast:
When two light beams with different polarization states are incident to the same type of scattering element (speckle eliminating device), the probability of generating independent speckle patterns is greatly increased. According to the above formula, the speckle contrast will be close
I.e., toward a smaller speckle contrast, so that a better speckle-resolving effect can be obtained.
Taking the arrangement shown in fig. 4A as an example, the polarization states of the laser beams in the first row and the second row are different, the polarization states of the laser beams in the second row and the third row are also different, and similarly, the polarization states of the laser beams in the third row and the fourth row are also different, so that the polarization states of the beams emitted by the four rows of light-emitting chips are opposite to each other.
Or as shown in fig. 4B, the first light-transmitting units 0222a and the second light-transmitting units 0222B may also be arranged in a row, and the first light-transmitting region includes three rows of the first light-transmitting units 0222a, such as a flat glass or a diffusion sheet, and the second light-transmitting region includes two rows of the second light-transmitting units 0222B, such as a quarter-wave plate, the laser beam still maintains the original polarization state after transmitting through the first light-transmitting units of the first light-transmitting region and is linearly polarized light, and the polarization state of the laser beam is converted from the original linear polarization to circular polarization after transmitting through the second light-transmitting units of the second light-transmitting region, and the laser beams in different polarization states are alternately arranged, and the whole laser beam may have multiple polarization states, and if the light intensity of each laser light-emitting chip is the same, the frequency is the same, which is different from the case shown in fig. 4A, the light intensity of the laser beams in different polarization states has a certain difference, no longer comparable. The effect of such decoherence is slightly lower than in the case shown in fig. 4A. Of course, the power of the laser light emitting chip can be adjusted to make the light intensity of the linearly polarized light and the circularly polarized light equal, so as to obtain a better speckle-dissipating effect.
In order to obtain the speckle contrast value as small as possible, and make the light intensities of the two lights with different polarization states as equivalent as possible without changing the light emitting power of the light emitting chip of the laser, it is preferable that the first light transmitting unit and the second light transmitting unit are arranged in a row or column interval arrangement when the number of rows or columns of the laser array is an even number.
Fig. 4C shows an arrangement example of a light transmitting unit of still another light transmitting portion. Wherein, the first light transmission unit 0222a and the second light transmission unit 0222b are arranged in a checkerboard manner, that is, the first light transmission unit and the second light transmission unit are adjacent to each other, when the laser light emitting chip is arranged in 4 × 5 rows and columns, the first light transmission unit is 10, the second light transmission unit is also 10, the laser light emitting chip emits linearly polarized light, the first light transmission unit 0222a is flat glass, and the second light transmission unit 0222b is a quarter wave plate, the light beam transmitted by the laser light emitting chip through the first row of light transmission unit is linearly polarized light, circularly polarized light, linearly polarized light, and linearly polarized light, the light beam transmitted by the second row of light transmission unit is circularly polarized light, linearly polarized light, circularly polarized light, and circularly polarized light, the third row is the same as the first row, the fourth row is the same as the second row, by such arrangement, the linearly polarized light and the transmitted light, the mixing is more uniform, and the total light intensity is equivalent, so that the coherence of light beams of adjacent light-emitting chips after passing through the light-transmitting part is reduced, and the speckle effect during laser projection display is favorably reduced.
And, in yet another embodiment, when the laser light emitting chips are not arranged in regular rows and columns, such as the case shown in fig. 4D, the laser light emitting chips can be arranged more compactly, which is beneficial to reducing the volume. Wherein the schematic first light-transmitting units in a checkered pattern and the schematic second light-transmitting units in diagonal line hatching are preferably arranged in such a manner that each first light-transmitting unit and each second light-transmitting unit are adjacent. Therefore, the adjacent light transmitting units can respectively emit laser beams with different polarization states as far as possible, the distribution of the linearly polarized light and the circularly polarized light is distributed in a balanced manner, the light intensity of the linearly polarized light and the light intensity of the circularly polarized light are equivalent, and the mixing and homogenizing degree is higher.
As can be understood by those skilled in the art, based on the above-mentioned distribution principle, in consideration of the convenience of manufacturing, it is preferable that when the number of rows or columns is selected to be even, the first light-transmitting unit and the second light-transmitting unit are arranged at a row interval or a column interval, and when the arrangement of the laser light-emitting chips is not a regular row-column arrangement, the two light-transmitting units are arranged in a manner that the first light-transmitting unit and the second light-transmitting unit are adjacent to each other two by two, so that the number of the two light-transmitting units is as large as possible.
In summary, in the arrangement of the light-transmitting portions illustrated in fig. 4A to 4D, because different regions of the light-transmitting portion have different processing manners for the laser beams, one region can allow the laser beams to emit according to the original polarization state, and the other region can change the polarization state of the laser beams, so that the laser light-emitting chip forms a mixed beam of the laser beams in different polarization states after transmitting the light-transmitting portion, and the two laser beams with the same light intensity have a greater probability of forming a plurality of independent speckle patterns, which is beneficial to speckle elimination, thereby reducing the coherence of the laser beams emitted from the laser array.
In the above example, the first light-transmitting unit may also be a quarter-wave plate, and the second light-transmitting unit may be made of flat glass or a diffusion sheet. The laser beam is changed from linearly polarized light to circularly polarized light after passing through the first light transmission unit, and the laser beam is still in the original linear polarization state after passing through the second light transmission unit, so that the laser beam emitted from one laser array comprises a plurality of polarization states, and the coherence between the laser beams is reduced to a certain extent.
It should be noted that the first light-transmitting unit, the first light-transmitting region, the second light-transmitting unit, the second light-transmitting region, and the laser light-emitting chip in the above examples emit linearly polarized light, and the circularly polarized light is not limited to the laser array, and is only used for illustrating a specific embodiment. In addition, in the implementation, those skilled in the art can understand that the material selection of the first light-transmitting unit and the second light-transmitting unit is not limited to the example of the embodiment, and the two units may be interchanged.
And, in practical application, because the divergence angles of the laser beam emitted by the laser light emitting chip on the fast axis and the slow axis are different, the actual laser beam is in a relatively large divergence state in the fast axis direction, for example, divergence of 30 degrees is performed, while the slow axis has only divergence angles of 8-10 degrees, and divergence conditions exist, therefore, as a laser array component, a beam which is relatively parallel is expected to be emitted theoretically, and therefore, the beam emitted by the laser light emitting chip also needs to be collimated, and the collimated beam is emitted in a substantially parallel state, which is beneficial to the design of a rear light path. In one embodiment, a microlens may be disposed directly above the laser light emitting chip as a collimating lens, and then the laser light emitting chip and the microlens are hermetically packaged, for example, the outermost layer of the laser array is disposed with a light transmissive layer and hermetically connected to the metal substrate, and the light emitting chip and the microlens are accommodated in the sealed space.
Referring to fig. 2B, a collimating part 023 is disposed on the light emitting side of the light-transmitting part 022, and the collimating part 023 is a collimating lens group, and is composed of a plurality of lens unit structures, and can collimate and converge light beams.
Referring to fig. 6, the collimating lens group includes a plurality of collimating lens units 0231, the number of the collimating lens units 0231 is the same as the number of the light emitting chips or the number of the light transmitting units of the light transmitting portions, that is, one collimating lens unit corresponds to one light transmitting unit of the light transmitting portion and also corresponds to one light emitting chip, and is configured to collimate the laser beam which is emitted by the corresponding light emitting chip and which is transmitted through the first light transmitting unit or the second light transmitting unit. The collimating lens group is arranged in the light-emitting direction of the laser beam. In practical applications, the plurality of collimating lens units may be arranged in an array, for example, as a fly-eye lens array.
Optionally, the collimating lens group can be integrally formed into a whole, so as to cover the light-emitting direction of the light-emitting chip or the light-emitting direction of the reflecting part; or each collimating lens group can be separately arranged and independently covered in the light-emitting direction of the light-emitting chip or the light-emitting direction of the reflecting part. The collimating lens group can be made of B270 or K9, and is made of optical glass with high light transmittance and high hardness.
Referring to fig. 5, which is a schematic structural diagram of a laser array package, a collimating part 053 is further disposed on the outermost side of the laser array, and specifically, the collimating part 053 is a fly-eye lens array. The periphery of the collimating part 053 is bonded with the light-transmitting part 052 or the periphery of the metal substrate 0512 through UV glue, so that the packaged laser array is formed. After packaging, the light emitting chip (not shown) is enclosed in a sealed space surrounded by the light-transmitting portion 052 and the metal substrate 0512. And a pin 0514 is led out from the side face of the metal substrate.
In one embodiment, the light emitting chip can be directly soldered to the metal substrate by solder, or, as shown in fig. 3A, the light emitting chip 0211 can be further connected to the metal substrate 0212 by a heat sink 0213, the light emitting chip 0211 is first fixedly connected to one side of the heat sink 0213 by soldering or thermal adhesive, and the other side of the heat sink is then fixedly connected to the metal substrate 0212 by soldering or thermal adhesive.
It should be noted that the connection method of the light emitting chip and the metal substrate is not limited specifically, and may be a welding method, or a heat conducting adhesive bonding method, as long as the connection method does not affect the heat conduction greatly.
Each light emitting chip can be connected in series through an electrical connection, and specifically, each light emitting chip can be connected with a gold wire, and the gold wire is finally connected to a Pin (Pin) to realize the electrification of each light emitting chip. Alternatively, the gold wire may be fixed to the metal substrate by means of gluing.
In one embodiment, the metal substrate in the laser array is preferably a copper substrate, which has good thermal conductivity and a thickness selected from the range of 1mm to 3 mm.
In one embodiment, the light beams emitted by the light emitting chips in the laser array may be all blue, green, or red; or one part of the light-emitting chips can emit blue light, and the other part of the light-emitting chips can emit red light or green light; and a part of the light emitting chips can emit blue light, a part of the light emitting chips can emit red light, and a part of the light emitting chips can emit green light.
In one embodiment of the present invention, if a plurality of light emitting chips in the laser array emit light of the same color, whether blue, red or green, wavelengths of light beams emitted by adjacent light emitting chips in the plurality of light emitting chips are different, that is, there is a certain wavelength difference. By adopting the design scheme, the time coherence influence between adjacent laser beams can be greatly reduced, and the speckle influence of laser display is reduced. In this embodiment, the wavelength difference is preferably at least 1nm, and more preferably 2 nm.
When the light emitting chip emits blue laser and red laser, the light emitting chip emitting blue laser and the light emitting chip emitting red laser are consistent with the arrangement rule of the first light transmitting unit and the second light transmitting unit. Therefore, the blue laser and the red laser have different wavelengths and different polarization states, and are beneficial to jointly dissipating the spots from two dimensions of time coherence and space coherence.
As shown in fig. 7A, a schematic diagram of a light emitting surface structure of a two-color laser array is shown, where a red laser emitting chip and a blue laser emitting chip may be arranged adjacent to each other, a first light transmitting unit and a second light transmitting unit respectively cover the light emitting surfaces of the blue laser emitting chip and the red laser emitting chip, and are also arranged at intervals, taking the first light transmitting unit as a quarter wave plate, and the second light transmitting unit as flat glass as an example, the first light transmitting units in the first row and the third row respectively normally transmit blue laser, and the second light transmitting units in the second row and the fourth row respectively transmit red laser whose polarization state is reversed.
Certainly, the red laser light emitting chips and the blue laser light emitting chips may also be arranged at intervals in rows or columns, for example, the first row and the third row are blue laser light emitting chips, the second row and the fourth row are red laser light emitting chips, and the first light transmitting unit and the second light transmitting unit are not arranged in rows or columns but arranged adjacently in pairs according to a checkerboard, so that a plurality of laser beams with different wavelengths and different polarization states can be obtained, and even if the wavelengths are the same, the polarization states can also be different, so that the speckle contrast of the laser beams in the polarization states can be reduced, and a better speckle elimination effect can be obtained.
As shown in fig. 7B, a schematic diagram of a light emitting surface structure of a three-color laser array is shown, wherein among a plurality of light emitting chips arranged in an array, red, green and blue three-color laser light emitting chips are included, wherein the first row and the second row are blue laser light emitting chips, the third row is a red laser light emitting chip, the fourth row is a green laser light emitting chip, wherein the first and third rows are provided with first light-transmitting units, the second and fourth rows are provided with second light-transmitting units, thus, the polarization states of the blue laser transmitted by the first row and the second row of light-transmitting units are different, the polarization states of the blue laser transmitted by the second row of light-transmitting units are different from the polarization states of the red laser transmitted by the third row of light-transmitting units, the polarization states of the red laser transmitted by the third row of light-transmitting units are different from the polarization states of the green laser transmitted by the fourth row of light-transmitting units, so that the whole laser array can emit a plurality of laser beams with different wavelengths and different polarization states.
The multicolor laser array in the above embodiment can emit laser beams with multiple wavelengths and different polarization states, and can also reduce the speckle effect of the laser beams based on the principle of reducing the speckle contrast with the polarized light, which is not described herein again.
Example II,
The invention also provides a laser light source, as shown in fig. 8, which comprises a laser array 801 and a converging and shaping component 802, wherein the converging and shaping component 802 converges and shapes laser beams emitted by the laser array 801 to form illumination beams, and the illumination beams are homogenized by a homogenizing part 803 and then emitted into an optical machine. The light uniformizing unit 803 may be a light guide or a fly eye lens. Before entering the laser beam after shaping, the laser beam may enter the leveling part 803 or after being leveled by the leveling part 803, and may pass through a moving diffusion wheel, a diffusion sheet, or a phase adjusting device, for example, to perform speckle reduction.
The laser array 801 in this embodiment may be any one of the examples of the laser array in the embodiments, and due to the adoption of the laser array, coherent characteristics or speckle effect of a laser beam can be suppressed from a source, a high-quality illumination beam is provided, more importantly, the use of a speckle elimination component in an optical path can be greatly simplified, the optical path architecture is simplified, and miniaturization is facilitated.
Example III,
The invention further provides a laser projection device, as shown in fig. 9, which includes a laser light source 901, an optical modulation device 902, and a projection lens 903, where the laser light source 901 emits a laser beam to form an illumination beam to irradiate the optical modulation device 902, specifically, to irradiate the optical modulation device 902, in a DLP architecture, the optical modulation device 902 may specifically be a DMD digital micromirror array including millions of tiny mirrors, the optical modulation device 902 modulates the illumination beam according to a driving signal corresponding to an image display signal, and the modulated light beam enters the projection lens to be imaged, where the laser light source is the laser light source in the above embodiment. The laser projection device provided in this embodiment may be a laser projector or a laser projection television, where the laser light source can improve a high-quality illumination beam, reduce a speckle effect, and facilitate simplification of an optical architecture to achieve miniaturization of the laser projection device.
In the description herein, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A laser array includes a light emitting portion that emits a laser beam, and a light transmitting portion that is provided along a light emitting direction of the light emitting portion and transmits the laser beam;
wherein the light-transmitting portion includes a first light-transmitting region and a second light-transmitting region, and the first light-transmitting region and the second light-transmitting region are arranged so that the light beams transmitted through the two regions from the light-emitting portion have polarization states of linear polarization and circular polarization, respectively.
2. The laser array of claim 1, wherein the light emitting section comprises at least a plurality of light emitting chips, a metal substrate, the plurality of light emitting chips being disposed on the metal substrate; the metal substrate of the light-transmitting part is matched to form a sealed space; the light emitting chips are all arranged in the sealed space.
3. The laser array of claim 1 or 2, wherein the light-transmissive portion comprises a window support, and the first light-transmissive region and the second light-transmissive region respectively comprise a plurality of first light-transmissive units and second light-transmissive units, and the plurality of first light-transmissive units and the second light-transmissive units are adhered to the window support; or,
the light transmission part comprises a light transmission glass plate, and the first light transmission area and the second light transmission area are formed on the light transmission glass plate through regional film coating.
4. The laser array of claim 3, wherein the first and second light-transmissive units are arranged in rows or columns.
5. The laser array of claim 3, wherein each of the first light-transmissive cells and each of the second light-transmissive cells are arranged adjacent to each other.
6. The laser array of any of claims 1 to 5, wherein one of the first and second light transmissive regions is a flat glass or a diffuser and the other is a quarter-wave plate.
7. The laser array of any one of claims 1 to 5, further comprising a collimating section, wherein the collimating section comprises a plurality of collimating lens units, and the number of the collimating lens units is equal to the number of the light emitting chips.
8. The laser array of claim 6 or 7, wherein the light emitting chip emits light beams with one of blue, green and red colors;
or the color of the light beam emitted by the light-emitting chip is any two of blue, green and red;
or the light-emitting chip emits blue laser, red laser and green laser.
9. A laser light source comprising the laser array according to any one of claims 1 to 8, and a converging/shaping member for converging and shaping a laser beam emitted from the laser array to form an illumination beam.
10. A laser projection device is characterized by comprising a laser light source, an optical modulation device and a projection lens, wherein the laser light source emits a laser beam to form an illumination beam to irradiate the optical modulation device, the optical modulation device modulates the illumination beam according to a driving signal corresponding to an image display signal, and the modulated beam enters the projection lens to be imaged, wherein the laser light source is the laser light source according to claim 9.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
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| CN201811118508.6A CN110928123A (en) | 2018-09-19 | 2018-09-19 | Laser array, laser light source and laser projection equipment |
| PCT/CN2019/084117 WO2020057124A1 (en) | 2018-09-19 | 2019-04-24 | Laser array, laser light source and laser projection device |
| US16/708,406 US11467477B2 (en) | 2018-09-19 | 2019-12-09 | Laser array, laser source and laser projection device |
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| CN201811118508.6A CN110928123A (en) | 2018-09-19 | 2018-09-19 | Laser array, laser light source and laser projection equipment |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111683235A (en) * | 2020-06-03 | 2020-09-18 | 青岛海信激光显示股份有限公司 | Laser projection device |
Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5533152A (en) * | 1995-05-02 | 1996-07-02 | Eastman Kodak Company | Method and apparatus for coupling light emitted from a multi-mode laser diode array to a multi-mode optical fiber |
| JP2008064794A (en) * | 2006-09-04 | 2008-03-21 | Seiko Epson Corp | Image display device |
| CN102402015A (en) * | 2011-11-07 | 2012-04-04 | 中国人民银行印制科学技术研究所 | Thin film device and manufacturing method of thin film device |
| CN103376636A (en) * | 2012-04-26 | 2013-10-30 | 索尼公司 | Display unit and illumination device |
| CN103946737A (en) * | 2011-11-25 | 2014-07-23 | 西铁城控股株式会社 | Optical device |
| CN104220922A (en) * | 2012-03-27 | 2014-12-17 | 菲力尔系统公司 | Scalable laser with selectable divergence |
| CN105182674A (en) * | 2015-10-28 | 2015-12-23 | 中视迪威激光显示技术有限公司 | Laser light source special for laser projector |
| CN107178711A (en) * | 2016-03-11 | 2017-09-19 | 杭州华普永明光电股份有限公司 | Light emitting diode module and preparation method thereof and light fixture |
| CN107275463A (en) * | 2017-05-22 | 2017-10-20 | 申广 | A kind of New LED encapsulates manufacturing technology |
| CN107505807A (en) * | 2017-10-10 | 2017-12-22 | 青岛海信电器股份有限公司 | A kind of LASER Light Source and projection display apparatus |
| CN107980182A (en) * | 2015-08-31 | 2018-05-01 | 西铁城电子株式会社 | Light-emitting device and its manufacture method |
| CN207457625U (en) * | 2017-11-22 | 2018-06-05 | 歌尔科技有限公司 | Disappear speckle device, laser light source and laser projection system |
| CN110928120A (en) * | 2018-09-19 | 2020-03-27 | 青岛海信激光显示股份有限公司 | Laser array, laser light source and laser projection equipment |
| CN110928119A (en) * | 2018-09-19 | 2020-03-27 | 青岛海信激光显示股份有限公司 | Laser array, laser light source and laser projection equipment |
-
2018
- 2018-09-19 CN CN201811118508.6A patent/CN110928123A/en active Pending
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5533152A (en) * | 1995-05-02 | 1996-07-02 | Eastman Kodak Company | Method and apparatus for coupling light emitted from a multi-mode laser diode array to a multi-mode optical fiber |
| JP2008064794A (en) * | 2006-09-04 | 2008-03-21 | Seiko Epson Corp | Image display device |
| CN102402015A (en) * | 2011-11-07 | 2012-04-04 | 中国人民银行印制科学技术研究所 | Thin film device and manufacturing method of thin film device |
| CN103946737A (en) * | 2011-11-25 | 2014-07-23 | 西铁城控股株式会社 | Optical device |
| CN104220922A (en) * | 2012-03-27 | 2014-12-17 | 菲力尔系统公司 | Scalable laser with selectable divergence |
| CN103376636A (en) * | 2012-04-26 | 2013-10-30 | 索尼公司 | Display unit and illumination device |
| CN107980182A (en) * | 2015-08-31 | 2018-05-01 | 西铁城电子株式会社 | Light-emitting device and its manufacture method |
| CN105182674A (en) * | 2015-10-28 | 2015-12-23 | 中视迪威激光显示技术有限公司 | Laser light source special for laser projector |
| CN107178711A (en) * | 2016-03-11 | 2017-09-19 | 杭州华普永明光电股份有限公司 | Light emitting diode module and preparation method thereof and light fixture |
| CN107275463A (en) * | 2017-05-22 | 2017-10-20 | 申广 | A kind of New LED encapsulates manufacturing technology |
| CN107505807A (en) * | 2017-10-10 | 2017-12-22 | 青岛海信电器股份有限公司 | A kind of LASER Light Source and projection display apparatus |
| CN207457625U (en) * | 2017-11-22 | 2018-06-05 | 歌尔科技有限公司 | Disappear speckle device, laser light source and laser projection system |
| CN110928120A (en) * | 2018-09-19 | 2020-03-27 | 青岛海信激光显示股份有限公司 | Laser array, laser light source and laser projection equipment |
| CN110928119A (en) * | 2018-09-19 | 2020-03-27 | 青岛海信激光显示股份有限公司 | Laser array, laser light source and laser projection equipment |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111683235A (en) * | 2020-06-03 | 2020-09-18 | 青岛海信激光显示股份有限公司 | Laser projection device |
| CN111683235B (en) * | 2020-06-03 | 2022-04-05 | 青岛海信激光显示股份有限公司 | Laser projection device |
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Application publication date: 20200327 |