Embodiment
With reference to embodiment and compare accompanying drawing the present invention is described in further details, for a better understanding ofThe present invention, but following embodiments are not intended to limit the scope of the invention.
Depth camera is broadly divided into structure light depth camera, TOF depth cameras and binocular vision depth camera by species.
Encoded standard knots are projected into space using laser projection device based on the trigon depth camera of structure lightThe difference of target depth is modulated normal structure light pattern in structure light pattern, space, is obtained by the related scheduling algorithm of imageThe difference of structure light image and normal structure light pattern after modulation is taken, it is deep with target to set up the difference according to structure light trigonometryRelation between degree can solve the depth image of whole object space.
Depth camera based on time flight method, to objective emission laser pulse, is filled using laser projection device by light-receivingPut acquisition pulse and record the light flight time for being transmitted into reception, the depth map of target can be calculated according to the flight timePicture.
Depth camera based on Binocular Vision Principle, substantially similar to structure light trigonometry principle, difference is structureLight trigonometry is actively to measure, and binocular vision is then passive measurement.Difference of the image obtained using left and right camera on parallaxNot, the depth value for further calculating target after the parallax using triangulation principle and is obtained by vision algorithm.
Usually, be required in first two depth camera by means of laser projection device come into space projection optics believeNumber, and for binocular vision depth camera, also can usually increase object in space using laser projection device at presentTexture information is to improve measurement accuracy.Because laser projection device is abnormal important for depth camera, often laser projectionPerformance, volume, the power consumption of device will directly affect precision, volume of depth camera etc..
The present invention proposes a kind of laser projection device and the depth camera based on this.Will be to laser in explanation belowIllustrated exemplified by projection arrangement and depth camera, but be not meant to that this laser projection device is only capable of applying in depth phaseIn machine, every direct or indirect utilization program is intended to be included within protection scope of the present invention in any other device.
The depth camera side schematic view based on structure light shown in Fig. 1.The main building block of depth camera 101 has laserModule 104, collection module 105, mainboard 103 and processor 102 are projected, RGB camera is further provided with some depth cameras107.Optical projection module 104, collection module 105 and RGB camera 107 are generally mounted at same depth camera planeOn, and in same baseline, each module or camera correspond to a light portal 108.Usually, processor 102 is collectedInto on mainboard 103, and optical projection module 104 is connected with collection model 105 by interface 106 with mainboard, in one kind implementationInterface described in example is FPC interfaces.Wherein, optical projection module is used to project encoded structure light figure into object spaceCase, collection module is collected after the structure light image by the processing of processor so as to obtain the depth image of object space.
In the present embodiment, structure light image be infrared laser speckle pattern, pattern have distribution of particles relatively uniform butWith very high local irrelevance, local irrelevance here refers to that each sub-regions are all with higher only in patternOne property.It is corresponding collection module 105 be and the corresponding infrared camera of optical projection module 104.Depth map is obtained using processorAs in particular to receiving after the speckle pattern collected by collection module, by calculating speckle pattern and reference speckle patternBetween deviation value further obtain depth image.
The array laser projection arrangement of the present embodiment, also known as laser projection module, as shown in Fig. 2 being laser projection in Fig. 1A kind of embodiment of module 104.Laser projection module 104 include base 201, light source, microlens array, main lens 205 andDiffraction optical element (DOE) 206.Base 201 is used for fixed light source, is also used for providing radiating, electrical connection in certain embodimentsDeng effect, such as the base collectively constituted by radiating piece, circuit board.The light source of laser projection module 104 includes multiple sub-light sourcesFor launching multiple beamlets, light source can be the LASER Light Sources, the species of light source such as visible ray, black light be for example infrared, ultravioletCan be edge emitting laser can also vertical cavity surface laser, in order that overall projection arrangement small volume, optimal schemeIt is to select the VCSEL array being made up of multiple vertical cavity surface generating laser VCSEL as light source.Illustrate for convenience in figure,3 sub-light source VCSEL 202 are only listed on one-dimensional, in fact VCSEL array is to fix X-Y scheme by multiple VCSEL202The two-dimension light source of case arrangement.In order that the pattern that laser projection device is launched has the characteristic such as uniform, uncorrelated, VCSEL gustsIn row VCSEL 202 arrangement pattern be irregular pattern, i.e. VCSEL light source not with regular array, but with certainIrregular pattern arrangement.In certain embodiments, the overall size of VCSEL array is only in micron dimension, such as 5mm*5mm is bigIt is small, tens even up to a hundred VCSEL light sources are arranged above, and the distance between each VCSEL light source is in micron dimension, thanSuch as 10 μm.
In the laser projection module of the present embodiment, microlens array includes multiple lenticule units 204, each lens unit204 correspond with the VCSEL light source of each in VCSEL array 202 respectively, i.e., each lenticule unit 204 in microlens arrayArrangement and each VCSEL light source 202 it is consistent, i.e., quantity is equal, and arrangement pattern is also identical.Each lenticule unit 204 is distinguishedLight beam and diverging for receiving corresponding VCSEL light source 202.Microlens array receives the light beam from light source, and to light beamDissipated, in order to reach the effect of diverging, lenticule unit 204 comprises at least a lens face 203, lens face one hereAs be concave spherical surface.In some embodiments, it is also possible to be aspherical, such as in one embodiment when light beam of light source be shaped as it is ellipseWhen circular, oval-shaped beam can not only be dissipated by cylindrical lens face, also carry out shaping to form circular light beam；AgainCircular light beam is such as shaped to the light beam shape with uniform shapes in an embodiment by the non-spherical lens of particular designShape, this set can cause the light beam that overall laser projection device is launched not only to have the effect of diverging, and its spot also hasThere is unified non-circular shape, be conducive to improving the accuracy of depth calculation in some cases；And for example in one embodiment,By the non-spherical lens of particular design to eliminate the ball-shaped aberration of lens to form more accurate speckle patterns.
When the lens unit of each in microlens array 204 only has a lens face 203, lens face 203 can be placed inTowards light source can also be placed in backlight while.In certain embodiments, each lens unit can also twoThere is lens face in face.
The lens unit of each in microlens array 204 is corresponded with the VCSEL light source of each in VCSEL array 202 respectively,Each VCSEL light source 202 is consistent in the arrangement of each lens unit 204 and VCSEL array i.e. in microlens array, i.e. quantity phaseDeng, arrangement pattern it is identical.Each lenticule unit 204 is respectively used to receive light beam and the diverging of corresponding VCSEL light source 202.The geometry of lenticule unit 204 can have various shapes, than six shown in round-shaped and Fig. 3 b as shown in Figure 3 aAngular shape or unshowned square, diamond shape etc..
In certain embodiments, lenticule unit 204 can also have a variety of geometries to collectively form, such as same micro-Half lenticule unit is hexagonal configuration in lens array, and second half lens unit is a kind of round-shaped, preferred embodiment partyFormula as shown in Figure 3 c, is mutually in staggered distribution between different shapes.This embodiment is advantageous in that, will be of different shapes micro-VCSEL light source corresponding to lens is separately controlled, such as the corresponding VCSEL light source of hexagonal configuration lenticule unit with it is round-shapedThe corresponding VCSEL light source of lenticule unit is grouped control, it is possible to achieve independent to open and synchronous opening, thus can obtainShape difference or the different transmitting beam pattern of density.Such as individually open corresponding to hex shape lenticule unitVCSEL light source, compared with individually opening the VCSEL light source corresponding to round-shaped lenticule unit, emitted beam patternShape it is different；Hexagon or the VCSEL light source corresponding to round-shaped lenticule unit are such as only opened, it is and fully openVCSEL light source is compared, and the density of emitted beam pattern is also different.It is to be appreciated that only being listed in explanation hereIt is divided into two groups of example, in fact, a greater variety of packets can also be carried out, for corresponding to same shaped microlenses unitVCSEL light source can also be grouped control, even, independent control can be carried out to each VCSEL light source.
When the shape of lenticule unit 204 is different, its corresponding focal length typically also has difference, when microlens array withThe timing of the distance between VCSEL array one, the focal length of lenticule unit is different, can cause the VCSEL light source of each in VCSEL arrayThe cross-sectional sizes of final outgoing beam also can be different.Even if lenticule unit is same shape, can also be by lenticule unitFocal length be arranged to difference to produce the discrepant transmitting beam pattern of size, in theory for, this mode can improve hairThe non-correlation degree of irradiating light beam pattern, can increase the cost of manufacture but then.
In a word, by the independent of each VCSEL light source, packet and integrally control, and to lenticule in VCSEL arraySetting in array in terms of lenticule cell configuration, focal length, can launch the different hair such as shape, size, densityIrradiating light beam is to meet different application demands.
Fig. 2 is returned to, lenticule unit 204 can regard beam divergence, its reverse extending line intersection point as focal plane 207, fromThe angle of imaging is light source in focal plane 207 into the virtual image, and usually focal plane 207 is located at the backlight side of light source.In lenticule listMain lens 205 is provided with after member 204, main lens 205 is used to the light beam of microlens array carrying out secondary focusing imaging, the opposing partyFace main lens 205 also plays the effect for being diffused beamlet, and diffusion here is referred to by the light beam by main lensFor the light beam of the surface of emission of VCSEL light source 202, the diameter of light beam is extended.Pass through multiple light of main lens 205Beam is transferred to diffraction optical element (DOE) 206, and is expanded by DOE206 with integral multiple.If than VCSEL light source 202Quantity is the beamlet of 100, i.e., 100, by being expanded after DOE with 500 times, ultimately forms the pattern of 50000 spotsProject in space.It should be noted, overlapping phenomenon occurs in the spatially different distance of this 50000 spots, thereforeOften spot number can be less than 50000.In other words, DOE effect is that the pattern for being formed light source 202 is carried out into spaceDuplication again, it should be noted that due to pattern density to be improved, when being replicated, had between two adjacent width patternsPartly overlap, overlapping another effect is can to improve the uncorrelated degree of global pattern.
Main lens 205 and DOE206 can be fabricated on same optical element in certain embodiments, to reach contractingThe effect of small size, the optical element has two surfaces, is respectively intended to perform the function of lens and diffraction optical element.
In the present embodiment, diffraction optical element 206 is DOE, and DOE is configured to receive the light beam of main lens transmitting and defeatedGo out structured light, what feature (such as spot or point) sum that its structure light includes included more than the light beam that main lens is sentFeature sum.Using this optical element, it can make have in the structured pattern of output more more special than in VCSEL unitLevy.So as to, if it is desired to the structured light pattern with 1,000 features is produced, then 1,000 are not needed in VCSEL arrayVCSEL units, can effectively reduce the overall size and volume of VCSEL array, and reduce overall size and cost.ReplacingIn embodiment, diffraction optical element is implemented as microlens array or grating.
In the laser projection module of the present embodiment, the distance between microlens array and VCSEL array light source need to carry outEspecially set, usually need to meet two conditions, one is to ensure each lenticule unit only by the light of single VCSEL light sourceInterference is not had between beam, adjacent beams；Two be that VCSEL array light source is preferably located within 1 times of focal length of lenticule unit, to protectCard light beam fully spreads.It is not the limit to the solution of the present invention it should be noted that only giving a kind of optimal case hereSystem.In addition, the distance between main lens and microlens array should typically be less than the focal length of main lens, a kind of preferred embodiment partyIn formula, this distance is less than main lens focal length and lenticule unit focal length sum.The distance between main lens and microlens arrayAbove-mentioned condition is only met, the secondary imaging light path that both form could realize lower multiplication factor.
The light path arrangement figure of the laser projection device of the present invention, is in fact also the secondary imaging to light source, with existing skillThe light path arrangement figure of single lens is compared in art, and the multiplication factor of secondary imaging can be adjusted, and the integrated level of system is higher.MeshThe multiplication factor of preceding single lens is general at 200 times or so, and the optical system that the present invention is made up of microlens array and main lensThe multiplication factor of system can then realize any multiple between 40~200.Smaller multiplication factor then means what is ultimately formedSpeckle pattern is more concentrated, and identical luminous power can be for transmission to farther distance and the higher pattern quality of holding, depthFigure computational accuracy will be higher.Need, such as telemeasurement, then can adjust micro- according further to different application scenariosThe distance between lens array and main lens are to increase multiplication factor, so that increase the projection spot size of laser projection module, withEnsure the speckle patterns for remaining to when remote obtain better quality, it is on the contrary then reduce multiplication factor.Adjust when mounted micro-The distance between lens array and main lens, the multiplication factor of laser projection device is it has been determined that multiplication factor after installationCan be any one numerical value between 40-200, compared to existing use different focal lens laser projection device andSpeech, because the multiplication factor of current single lens is generally 200 or so, it is impossible to realize that lower multiplication factor makes to ultimately formSpeckle pattern more concentrate, therefore, laser projection device of the invention, either in cost or implementation, all than existingSome laser projection devices have bigger advantage.
In addition, the microlens array that the present invention is constituted using concavees lens, at least following two for convex lensThe advantage of aspect.One side concavees lens are spread VCSEL light source light beam, cause the hot spot on DOE more big and equalEven, the intensity of the structured light patterns of formation can be more uniform；Another aspect concavees lens to light beam due to playing diffusion, and light beam existsProject module internal distribution relatively uniform, and convex lens then can be high in inside generation focus, the i.e. luminous power for projecting modulePoint so that the too high final influence projection quality of temperature of projection module.
Fig. 4 is single VCSEL structural representation.In Fig. 4,401 be single VCSEL, and usually, VCSEL's is activeLayer 405 is in centre, and what is be connected with active layer is limiting layer 406, and the effect of limiting layer is for controlling light field and electric current to realizeThere is the semiconductor mirror 404 and 407 of p-type and N-type at control to laser shape etc., active layer two ends, speculum 407 it is anotherSide is top electrodes 408 (P poles, positive pole), and the side of speculum 404 is Semiconductor substrate 403 and bottom electrode 402 respectively(N poles, negative pole).
In certain embodiments, VCSEL array light source can also be packaged into chip by special purposes, similar to electricityThe chips such as the CPU of brain, both positive and negative polarity is connected by being connected to pin in the same side with the external world.For depth phase of the present inventionFor machine embodiment, in order to reach the effect of small volume, a kind of preferably processing mode is directly partly to lead unencapsulated VCSELBody section chip is placed on base 201.The bottom of chip is connected with negative pole, and top is connected with positive pole.
Shown in Fig. 5 is laser projection device schematic diagram according to another embodiment of the present invention, is laser projection mould in Fig. 1Another embodiment of group 104, including base 201, VCSEL array light source, microlens array, main lens 205 and diffraction lightLearn element (DOE) 206.Microlens array include multiple lenticule units 204, each lens unit 204 respectively with VCSEL arrayIn each VCSEL light source 202 correspond, i.e., the arrangement of each lenticule unit 204 and each VCSEL light in microlens arraySource 202 is consistent, i.e., quantity is equal, and arrangement pattern is also identical.Each lenticule unit 204 is respectively used to receive corresponding VCSELThe light beam of light source 202 and diverging., in the present embodiment, will be micro- in order to further reduce the overall volume of laser projection deviceMirror unit 204 carried out with VCSEL light source 202 it is integrated, it is integrated after situation as figure 5 illustrates, this mode can cause laser projectionThe overall volume of device is smaller, and lenticule unit 204 and VCSEL light source 202 are by the strict one-to-one relation of holding, noIt can be influenceed by error caused by installing etc..
The details of the VCSEL light source 501 of integral micro-lens will be further described in Fig. 6.VCSEL active layer 605 in centre,What is be connected with active layer is limiting layer 606, and the effect of limiting layer is to realize to laser shape etc. for controlling light field and electric currentControl, there be the semiconductor mirror 604 and 607 of p-type and N-type at active layer two ends, and the opposite side of speculum 607 is top electricityPole 608 (P poles, positive pole), the side of speculum 604 is Semiconductor substrate 603 and bottom electrode 602 (N poles, negative pole) respectively.Laser beam is sent between P poles 608, by making lenticule 609 on speculum 607 to realize integrated effect, such as is existedBy depositing SiO on speculum 607 in a kind of embodiment2-Si3N4So as to form lenticule.The VCSEL battle arrays of integral micro-lensRow 701 are as shown in fig. 7, the VCSEL light source 601 of integral micro-lens is arranged in Semiconductor substrate 702 with irregular pattern, eachLight source surface has and its one-to-one lenticule.
In the VCSEL array 701 of integral micro-lens, the control to the VCSEL light source 601 of each integral micro-lens can haveDifferent patterns, in one embodiment, all VCSEL light sources are in synchronized control opening with closing；In another embodimentIn, VCSEL light source is controlled to produce different illumination density by independent or packet.The shape of single VCSEL light source, area also may be usedTo differ.
In certain embodiments, the VCSEL array light source of integral micro-lens can also be packaged into by special purposesChip, similar to chips such as the CPU of computer, both positive and negative polarity is connected by being connected to pin in the same side with the external world.For this hairFor bright described depth camera embodiment, in order to reach the effect of small volume, a kind of preferably processing mode is directly will notThe VCSEL semiconductor slice chips of encapsulation are placed on base 201.The bottom of chip is connected with negative pole, and top is connected with positive pole.
In another embodiment, laser projection device can utilize wafer scale optical technology, slot on a semiconductor substrate,Light source VCSEL202, lenticule unit 204, main lens 205 and diffraction optical element 206 are all directly produced on semiconductor liningIn the fluting at bottom.On the one hand the benefit of this technique reduces the volume of overall module, on the other hand can be same on waferWhen make multiple modules, it is last it is cleaved form multiple independent modules, so as to increase substantially production efficiency.
, can be directly by unencapsulated VCSEL semiconductor slices for laser projection device in order to further reduce volumeChip is placed on base 201, the bottom cathode connection of chip, the connection of top positive pole.To be cut into slices core with VCSEL in the following descriptionIllustrated exemplified by piece, it will be appreciated that encapsulation chip is also contained in protection scope of the present invention.In following elaboration,In order to make it easy to understand, will be with the word such as " chip ", " array chip " come instead of VCSEL array mentioned above.
Chip has been required for carrying and bindiny mechanism, to ensure the normal function of chip.Its promising independence of such as computer CPUThe bite type connection of design and fixed mechanism；For the little special chip of some caloric values, pin and mainboard directly can be passed throughIt is joined directly together；And for chip of the present invention, typically there is higher caloric value, and need firm fixed dressPut.VCSEL array chip is due to being for launching light beam, it is necessary to larger power, caloric value is larger, further needing exist for being integratedInto the micromodule equipment of small volume, heat dissipation problem needs to solve；On the other hand, for depth camera, laser projection mouldThe relative position requirement of group is consolidated very much, to ensure to have stabilization, accurate depth image to export.Therefore, VCSEL array chipCarrying requires both to possess small volume in order to integrated with bindiny mechanism, preferable heat dispersion is needed again and firmConnection.
The laser projection device of the present invention is realized small volume using a kind of special structure type in depth camera, dissipatedThe advantages of heat is high, the structure is in the bottom of laser projection device, specifically, including support member, for carrying chip；RadiatingPart, scatters and disappears for the heat that produces chip；Control unit, works for control chip, and the base 201 in Fig. 2 is useIn carrying and connecting VCSEL array chip, in embodiment 4-8, base 201 is configured to chip insertion as illustrated in figs. 8-11Device 801, i.e. base 201 play the triple role of support, radiating and control chip；Chip is specially VCSEL array chip806；Control unit is specially circuit board 803, accesses electrode to power or control VCSEL array chip by its interface 804806；Support member and thermal component are specially same part, i.e. substrate 802.
In the present embodiment, base 201 is configured to chip flush mounting 801 as shown in Figure 8.In the present embodiment,Chip is specially VCSEL array chip 806；Control unit specifically be circuit board 803, by its interface 804 access electrode withPower supply or control VCSEL array chip 806；Support member and thermal component are specially same part, i.e. substrate 802, are used forPlace and carry chip, and be connected with chip and to play a part of radiating and/or electrode connection, conventional material for copper it is gold-plated,Ceramics etc..The device easily can be attached with other control units such as mainboard, and can stably support chip.
In the present embodiment, in order to reduce overall volume, what is taken is the shape of the increase hole in the middle of circuit board 803Formula, substrate 802 is glued with circuit board 803, and covers hole (usually, being overlapped in the middle of hole center and circuit board 802),Then chip is placed in hole and be connected with substrate.This set be advantageous in that can and meanwhile take into account circuit board and chip itBetween connection and integral thickness control.
In another embodiment, in chip flush mounting 801, as shown in figure 9, circuit board 803 is flexible PCB(FPC), substrate 802 is copper gilding, and VCSEL array chip 806 is located at hole center, and passes through conductive silver paste and substrate802 connections, substrate 802 is glued with circuit board 803.Some pads 805 are arranged around FPC hole, pad 805 passes through lineRoad is connected with interface 804.In fig .9, positive terminal pad is connected by gold thread 807 with VCSEL chips apex electrode 806, negative pole welderingDisk is directly connected by gold thread 808 with substrate 802, because substrate is connected with the bottom electrode of chip by conductive silver paste, thusAlso it is achieved that being indirectly connected with for pad and bottom electrode.Further, since VCSEL chips are connected with substrate 802, and substrate hasGood thermal conductivity, therefore the heat dissipation problem of VCSEL chips is also resolved.
In another embodiment, physical connection, such as bolt etc. are passed through between circuit board 803 and substrate 802.If utilizing glueWater is connected, and advantage is to be not take up space, simple operation, but has the disadvantage because the resistance of glue is larger, thus is unfavorable for radiating,Power consumption can be increased.Specific connected mode is not limited herein.
In another different embodiment, circuit board 803 is printed circuit board (PCB) and flexible PCB (FPC)With reference to, i.e. rigid-flexible circuit board, compared with FPC, PCB hardness is high, and load-carrying properties preferably, but connect then more difficult.CauseThis, in the present embodiment, employs position FPC where the mode of the two combination, i.e. interface, and at the position being connected with substrateUsing Rigid Flex.In other embodiments, circuit board 803 can be all using printed circuit board (PCB).
The connection of circuit board and chip and substrate, more clearly visible Figure 10.In Fig. 10, circuit board 803 passes through gold thread807 and 808 are connected with chip 806 and substrate 802 respectively.Usually, the bore hole size of circuit board should be greater than the chi of chip 806It is very little, on the one hand it is easily installed and reserves operation space for the connection of gold thread 808 and substrate 802, on the other hand further improvesThe heat dispersion of substrate 802.Hole it is generally circular or square, do not limit herein.
In other embodiments, the gold thread of connection any can also can realize the material being conductively connected for other.
Can be chip recessing in substrate to further reduce volume, as shown in figure 11, this mode can be withFurther reduce overall thickness.It should be noted that when substrate thickness itself with regard to it is relatively thin when it is not recommended that recessing, to avoid working asChip adstante febre can cause the deformation of base material.
In other embodiments, substrate can also be other Heat Conduction Materials, such as ceramic.Now, VCSEL chips and substrateOnly heat conduction is connected, and is conductively connected with the positive and negative electrode of circuit board, connected mode can take any other to realize and be conductively connectedMode, do not limit herein.
In other embodiments, substrate can also be designed to be adapted to the shape of radiating, such as increase the mode such as flabellum withIncrease area of dissipation etc..Carrying out substrate can also being attached with other heat sink materials in integrating process with the equipment such as mobile phoneWith heat radiation performance.
Laser projection device having thus described the invention, chip is fixed using chip flush mounting, byHole is opened up on control unit, and VCSEL array chip is embedded, can fully reduce the overall volume of device, simultaneouslyChip directly contacts connection with thermal component, and thermal component plays a part of supporting chip simultaneously, it is ensured that provide maximum to chipThe radiating of limit.Compared with prior art, small size, high radiating, low-power consumption can be not only realized, lower put can also be realizedThe image quality of big multiple and Geng Gao.
Above content is to combine specific preferred embodiment further description made for the present invention, it is impossible to assertThe specific implementation of the present invention is confined to these explanations.For those skilled in the art, do not taking offOn the premise of from present inventive concept, some equivalent substitutes or obvious modification can also be made, and performance or purposes are identical, all shouldWhen being considered as belonging to protection scope of the present invention.