Patent ID: 12235466

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following description is disclosed to enable any person skilled in the art to make and use the present invention. Preferred embodiments are provided in the following description only as examples and modifications will be apparent to those skilled in the art. The general principles defined in the following description would be applied to other embodiments, alternatives, modifications, equivalents, and applications without departing from the spirit and scope of the present invention.

It is appreciated that the terms “longitudinal”, “transverse”, “upper”, “lower”, “front”, “rear”, “left”, “right”, vertical”, “horizontal”, “top”, “bottom”, “exterior”, and “interior” in the following description refer to the orientation or positioning relationship in the accompanying drawings for easy understanding of the present invention without limiting the actual location or orientation of the present invention. Therefore, the above terms should not be an actual location limitation of the elements of the present invention.

It is appreciated that the terms “one”, “a”, and “an” in the following description refer to “at least one” or “one or more” in the embodiment. In particular, the term “a” in one embodiment may refer to “one” while in another embodiment may refer to “more than one”. Therefore, the above terms should not be an actual numerical limitation of the elements of the present invention.

The existing three-dimensional sensing device, such as smart phones, tablet computers, lidar, wearable devices, somatosensory interactive equipment, VR equipment, AR equipment, industrial testing equipment, ranging equipment or stereo imaging equipment, generally comprises a complicated optical system. Accordingly, such system comprises a plurality of independent optical components to correct the off-axis distortion, wherein such system has disadvantages of inconvenience to assemble and adjust, large modular size, and higher cost, such that the existing technologies are hard to promote and to be widely used. As shown inFIGS.1to3B, a light field modulator10of a light modulator according to a preferred embodiment of the present invention is illustrated to solve the above mentioned problems. The light field modulator10is configured for modulating a light beam to achieve a uniform light effect and to correct an off-axis distortion at the same time.

Specifically, as shown inFIGS.1to3, the light field modulator10comprises at least one beam homogenizer11and a curved light transmitting substrate12having at least one curving surface120, wherein the beam homogenizer11is formed on the curving surface120of the curved light transmitting substrate12. Preferably, the microstructures of the beam homogenizers11are arranged along the curving surface120of the curved light transmitting substrate12. In other words, the beam homogenizer11is integrally formed with the curved light transmitting substrate12, such that the light field modulator10is implemented as a curved light modulator. It should be understood that the curved light transmitting substrate12can be, but is not limited to, made of transparent materials such as glass, resin, plastic, polymer materials, etc., as long as it can allow light beams to pass through.

It is worth mentioning that since the beam homogenizer11can homogenize the light beam, and the curved light transmitting substrate12can deflect the light beam to adjust a divergence angle range of the light beam. Therefore, modulating the light beam by the light field modulator10is to uniformly illuminate the target area, to reduce the off-axis distortion, and to minimize the energy loss, so as to enhance the uniformity of illumination and energy utilization, and to ensure a sufficient high window efficiency.

In one example, as shown inFIG.1, the curved light transmitting substrate12, which is embodied, but not limited to, as a curved lens, has a light incoming surface121and a light outgoing surface122opposite to the light incoming surface121, wherein the light incoming surface121of the curved light transmitting substrate12is curved to serve as the curving surface120of the curved light transmitting substrate12, while the light outgoing surface122of the curved light transmitting substrate12is flat. The beam homogenizer11is disposed on the light incoming surface121of the curved light transmitting substrate12, i.e. the beam homogenizer11is formed on the curving surface120of the curved light transmitting substrate12. It should be understood that the light beam enters from the light incoming surface121of the curved light transmitting substrate12and exits from the light outgoing surface122of the curved light transmitting substrate12.

It is appreciated that in another example, the light incoming surface121of the curved light transmitting substrate12can be configured as a flat surface while the light outgoing surface122of the curved light transmitting substrate12can be configured as a curved surface to serve as the curving surface120of the curved light transmitting substrate12, wherein the beam homogenizer11is disposed on the light outgoing surface122of the curved light transmitting substrate12.

More specifically, in a specific example of the present invention, the beam homogenizers11are attached to the curved light transmitting substrate12along the curvature thereof.

It should be appreciated that in another specific example of the present invention, the beam homogenizers11are integrally formed on the curving surface120of the curved light transmitting substrate12. In other words, the beam homogenizers11and the curved light transmitting substrate12are integrated to form a single member. Therefore, the light field modulator10of the present invention is highly integrated, easy to assemble and adjust, light weight, small size, and low cost, so as to enable the light filed modulator10equipping with the electronic device or system in an integrated and light weight manner.

It is worth mentioning that a person who skilled in the art can understand that the above specific integration structure of the beam homogenizer11and the curved light transmitting substrate12is an example, and should not be limited for the light modulator10of the present invention.

Furthermore, the beam homogenizer11should not be limited, for example, but not limited to, as a micro lens array constructed by convex lenses, micro lens array composed of concave lenses, regular micro lens array, random micro lens array, spherical lens array or aspheric lens array, etc.

Furthermore, the curved light transmitting substrate12(such as the curved lens) should not be limited, for example, but not limited to, as a plano-convex aspheric cylindrical lens, such as a spherical lens, aspherical lens, plano-convex lens Plano-concave lenses, bi-convex lenses, bi-concave lenses, meniscus lenses, etc., wherein the aspheric lens surface is expressed as:

z=ρ2R⁡(1+1-(1+k)⁢(ρ2)R2)+A4⁢ρ4+A6⁢ρ6+A8⁢ρ8+A10⁢ρ10+A12⁢ρ12+…

In one example of the present invention, the curved lens is implemented as a plano-convex aspheric cylindrical lens, and its surface shape is set as:

z=Y2R⁡(1+1-(1+k)⁢(Y2)R2)+A4⁢Y4+A6⁢Y6+A8⁢Y8+A10⁢Y10+A12⁢Y12wherein, the parameters of the curved lens as shown in Table 1.

TABLE 1R1.36 mmk−0.792A4−4.73E−03A6−8.00E−04A8−3.34E−04A102.24E−04A12−6.08E−05

According to the preferred embodiment, the beam homogenizer11provided on the curved lens is a micro lens array, and the direction of the micro lens is aligned with the surface normal of the curved lens, wherein the surface configuration of each micro lens is set as:

z=cx⁢x2+cy⁢y21+1-(1+kx)⁢cx2⁢x2-(1+ky)⁢cy2⁢y2wherein cxand cyare the curvatures of the micro lens in the X and Y directions, and kxand kyare the corresponding conic coefficients. The parameters of the micro lens are shown in Table 2. The light path diagram corresponding to this specific example is shown inFIG.3.

TABLE 2cx−8.84 mm−1cy−2.5 mm−1kx−1.12ky−1.08

In one example of the present invention, the light field modulator10can incorporate with a random micro lens array, wherein the surface configuration of each micro lens is set as:

z=cr21+1-(1+k)⁢c2⁢r2+∑i=1N⁢Ai⁢Ei⁡(x,y)
wherein,

cr21+1-(1+k)⁢c2⁢r2
is a basic aspheric term, where c is the curvature and k is the conic coefficient,

∑i=1N⁢Ai⁢Ei⁡(x,y)
is an extended polynomial, where N is the number of polynomials, and Ai is the coefficient of the ithextended polynomial term. The polynomial Ei(x,y) is the power series of x and y. The first item is x, then y, then x*x, x*y, y*y, . . . , etc.

It is worth mentioning that different microstructures of the beam homogenizer11of the light field modulator10can incorporate with different surface parameters. After the modulation of the different microstructures of the light field modulator10, the corresponding light beam can illuminate the corresponding target area to fulfill specific requirements. In other words, the present invention provides a predetermined flexibility to adjust the light field distribution by controlling the surface configuration of the microstructure in the light field modulator10so as to meet the specified light field requirements.

It is worth mentioning thatFIGS.4A to4Cillustrate a first alternative mode of the light field modulator10as a first modification thereof according to the above preferred embodiment of the present invention. Comparing to the preferred embodiment of the present invention, the difference between the first alternative mode and the preferred embodiment of the light field modulator10is that: there are two beam homogenizers11in the light field modulator10, wherein one of the beam homogenizers11is formed on the light incoming surface121of the curved light transmitting substrate12while another beam homogenizer11is formed on the light outgoing surface122of the curved light transmitting substrate12.

Accordingly, when the light beam is modulated by the light field modulator10, the light beam will pass through the two beam homogenizers11and one curved light transmitting substrate12, such that the light beam will be homogenized twice via the two beam homogenizers11. Between the two uniforms of the light beam, the light beam is deflected and adjusted its divergence angle range via the curved light transmitting substrate12. In other words, the light field modulator10of the present invention combines the two beam homogenizers11on two opposite surfaces of the curved light transmitting substrate12to simplify the microstructure of the beam homogenizers11and to create two relatively simple microstructures on two surfaces of the curved light transmitting substrate12. Therefore, the present invention can effectively simplify the complicated structure and manufacturing process of the light field modulator10, enhance the design and processing flexibility of the light field modulator10, and reduce the manufacturing cost of the light field modulator10at the same time.

Furthermore, in one example as shown inFIGS.4A to4C, the light incoming surface121of the curved light transmitting substrate12is configured in a first direction of a one-dimensional regular micro lens array to mainly adjust the light beam with the uniform light effect in the first direction. The surface configuration of the one-dimensional regular micro lens array is set as:

z=4.4⁢x21+1+1.95⁢x2

Correspondingly, the light outgoing surface122of the curved light transmitting substrate12is configured in a second direction of a one-dimensional random micro lens array to mainly control the light beam with the uniform light effect in the second direction. The one-dimensional random micro lens array is set as:

z=cy21+1-(1+k)⁢y2
wherein c is set with a value between 1 and 2.5, and k is set as a value between −1.2 and −0.9.

Preferably, one of the beam homogenizers11is arranged on one side of the curved light transmitting substrate12in the first direction, while another one of the light homogenizing elements11is arranged on an opposed side of the curved light transmitting substrate12in a second direction, wherein the first direction and the second direction are orthogonal. By adjusting the light beams with the uniform light effect in the first and second directions each light beam can uniformly illuminate the corresponding area after penetrating through the light field modulator10, as shown inFIGS.5A and5B. In other words, the light field modulator10of the present invention can significantly correct the distortion of the illumination light area, reduce energy loss, and improve uniformity and window efficiency of the module.

It is worth mentioning that the surface configuration of the one-dimensional regular micro lens array is merely an example, and should not be a limited for the scope of the light field modulator10of the present invention. For example, in one embodiment of the present invention, the beam homogenizer11is embodied as the one-dimensional regular micro lens array, wherein the surface configuration of the one-dimensional regular micro lens array is set as:

z=cx⁢x21+1-(1+kx)⁢x2⁢⁢or⁢⁢z=cy⁢y21+1-(1+ky)⁢y2wherein the value range of each of cxand cyis from −40 mm-1 to 40 mm−1, the value range of each of kxand kyis from −100 to 100. In another example of the present invention, the beam homogenizer11can be embodied as the one-dimensional random micro lens array, wherein the one-dimensional random micro lens array is set as:

z=cx⁢x21+1-(1+kx)⁢x2⁢⁢or⁢⁢z=cy⁢y21+1-(1+ky)⁢y2
wherein the value range of each of cxand cyis from −40 mm-1 to 40 mm−1, the value range of each of kxand kyis from −100 to 100.

In addition, the one-dimensional structure provided on the two surfaces of the curved light transmitting substrate12is simplified to simplify the design and manufacturing process of the light field modulator10, so as to reduce the manufacturing cost of the light field modulator10.

It is worth mentioning that according to the first alternative mode of the present invention, since the light incoming surface121of the curved light transmitting substrate12is a curve surface while the light outgoing surface122of the curved light transmitting substrate12is a flat surface, the light beam is configured not only for being initially uniformed by the beam homogenizer11at the light incoming surface121of the curved light transmitting substrate12but also for performing off-axis distortion correction on the light field formed by the light beam at the same time. Then, after the light beam is deflected and adjusted its divergence angle range through the curved light transmitting substrate12, the light beam is configured for being secondly uniformed by the beam homogenizer11at the light outgoing surface122of the curved light transmitting substrate12so as to further improve the uniformity of the light field

In order to further improve the off-axis distortion correction of the light field modulator10, a second alternative mode of the preferred embodiment is shown inFIG.6as another modification of the preferred embodiment. Comparing to the first alternative mode of the present invention, the difference of the second alternative mode to the first alternative mode is that: both of the light incoming surface121and the light outgoing surface122of the curved light transmitting substrate12are curved surfaces, wherein the light beam is configured not only for being initially uniformed by the beam homogenizer11at the light incoming surface121of the curved light transmitting substrate12but also for performing off-axis distortion correction on the light field formed by the light beam at the same time. Then, after the light beam is deflected and adjusted its divergence angle range through the curved light transmitting substrate12, the light beam is configured for being secondly uniformed and for being corrected the off-axis distortion at the same time by the beam homogenizer11at the light outgoing surface122of the curved light transmitting substrate12so as to further improve the uniformity of the light field and further improve the off-axis distortion correction for the light beam.

According to another example of the present invention as shown inFIG.7, the present invention further comprises a detection module1operatively connected to the light field modulator10, wherein the detection module1has a detection area200configured for detecting depth image information therewithin. Furthermore, as shown inFIG.8, the detection module1can be installed into an electronic device. In other words, the electronic device is constructed to have at least one detection module1operatively connected to an electronic device body300, such that the electronic device is able to acquire real three-dimensional information within the detection area200.

It is worth mentioning that the specific implementation of the electronic device body300or the electronic device should not be limited. For example, the electronic device can be embodied as, but not limited to, a smart phone, a tablet computer, a wearable device, a somatosensory interaction device, a VR device, an AR device, a distance measuring device, a 3D imaging device, or other electronic devices known to those skilled in the art. Furthermore, a person who skilled in the art should understand that the above mentioned application of the detection module1is only an example and should not be limited for the scope of the detection module1of the present invention. The detection module1can also be applied to other fields. For example, the detection module1can be applied to, but not limited to, gesture sensing or proximity detection of user interfaces, computers, household appliances, industrial automation, intelligent robots, drone, Internet, or other fields.

Furthermore, as shown inFIG.9, the detection module1can divide the detection area200into a plurality of designated areas201, wherein the designated areas201are detected at a predetermined time sequence, such that when the designated areas201are completely detected in time sequence, the real three-dimensional information in the detection area200is obtained.

Specifically, as shown inFIGS.7and9, the detection module1further comprises a detection light source20and a light receiving device30incorporating with the light field modulator10, wherein the detection light source20is configured to emit a plurality of detection light at a predetermined time sequence and to propagate to the designated areas201of the detection area200after being modulated by the light field modulator10. When an object is located at one of the designated areas201of the detection area200, the detection light will be reflected by the object to form a reflected light. The light receiving device30is configured to receive the reflected light and combines the detection light and its related information representing the depth image information of the designated area201. It should be understandable that the light receiving device30is configured to calculate the corresponding depth information of the detection area200by measuring the flight time of the photon. Alternatively, the light receiving device30can calculate the corresponding depth information of the detection area200according to information such as the phase difference between the detection light and the reflected light.

It is worth mentioning that, according to the above preferred embodiment of the present invention, as shown inFIG.9, the detection light source20comprises a plurality of illumination light sources21which are independently operated, wherein the illumination light sources21are configured corresponding to the designated areas201of the detection area200respectively. The illumination light sources21are switched on at the predetermined time sequence, such that the illumination light sources21are configured to sequentially generate the detection light to the designated areas201in order to detect the depth image information at each of the designated areas201. In other words, the illumination light sources21are switched on sequentially to generate the detection light, the power supply for the illumination light sources21will be substantially reduced so as to reduce the power consumption of the detection module1. Furthermore, under the same power supply condition, comparing to the existing ToF detection device, the detection module1of the present invention is able to acquire longer detection distance and to improve the detection range of the detection module1, so as to achieve the features of long-distance detection and low power consumption of the detection module of the present invention.

It is worth mentioning that the specific number of the illumination light sources21of the detection light source20should not be limited, wherein two or more of the illumination light sources21of the detection light source20may be implemented in the present invention. For example, four illumination light sources21are used, or a light emitting surface of the detection light source20is evenly divided into 4 sub-light-emitting surfaces in a 2*2 manner. Alternatively, fourteen illumination light sources21are used, or the light emitting surface of the detection light source20is evenly divided into 14 sub-light-emitting surfaces in a 2*7 manner. For another example, twelve illumination light sources21are used, or the light emitting surface of the detection light source20is evenly divided into 12 sub-light-emitting surfaces in a 1*12 manner. Furthermore, the type of the illumination light source21of the detection light source20should not be limited. For example, the illumination light source21can be, but not limited to, a VCSEL (Vertical Cavity Surface Emitting Laser) light source, EEL (side emitting laser) light source or LED (light emitting diode) light source. A person who skilled in the art should understand that the specific implementations or examples of the illumination light source21and the detection light of the detection light source11are merely illustrative, and should not be limited for the scope of the detection module1of the present invention.

It is appreciated that, in another example of the present invention, the detection light source20can be constructed to have only one illumination light source21, wherein the illumination light source21is configured to generate the detection light in a regional manner through the light field modulator10, so as to illuminate the designated area as required. Therefore, different designated areas are controllably illuminated to complete the regional detection via the detection module1.

It is worth mentioning that the light field modulator10of the present invention is able to solve the problem of distortion when the detection light emitted by the illumination light source21passes through a conventional uniform element. Specifically, according to the different arrangements of the illumination light source21of the detection light source20, the off-axis amounts of the illumination light source21at different positions are different. When the detection light generated by each illumination light source21passes through a conventional modulator, the center direction of the detection light is deflected at different angles. The closer the illumination light source21to the edge is, the greater the deflection angle of the detection light is. The distortion must be accurately corrected at the illuminating light area where the greater distortion occurs. Since the amount of distortion of the illumination light area formed by the detection light from the illumination light source21at different positions are different, the distortion must be corrected in these positions, such that it is difficult for the manufacturers to design, process, and assemble the detection module1.

In other words, as different positions and/or different angles of light beams correspond to different off-axis amounts, when different light beams pass through the conventional beam homogenizer the central direction of the light beam is deflected at different angles, wherein the closer to the edge is, the greater the deflection angle of the light beam is. Therefore, the distortion must be accurately corrected at the illuminating light area where the greater distortion occurs. However, since the amount of distortion of the illumination light zone formed by the light beams at different positions are different, the distortion must be corrected in a regional manner, which is difficult to design, process, and assemble.

In one example, without accurately correcting the distortion,FIGS.10A to10Fsequentially illustrate that the illumination light source21generates the light beams to illumination light zones at positions from close to the optical axis to far away from the optical axis.FIG.10Gis a schematic diagram of the illumination light zones formed by all the light beams. Accordingly, the illumination light zone illuminated by the detection light near the center is formed in a rectangular shape that the long sides thereof are extended in the horizontal direction while the illumination light zone illuminated by the detection light near the edge is formed in an arc-shape. However, the designated area201of the target area200is still formed in a rectangular shape, such that only a small area at the center of the designated area201will be an effective area among all of the designated areas201illuminated by the detection light. In other words, the farther the illumination light source21deviates from the optical axis, the greater the distortion of the illumination light zone formed by the detection light is. As a result, the lighting uniformity is poor, the energy utilization is low, the energy loss at the edge is huge, and the window efficiency is low due to the large off-axis distortion.

Since the detection light generated by the illumination light source21at different positions has almost no distortion in the illumination light zone after the light beams pass through the light field modulator10of the present invention, and there is no need to individually correct the distortion of each designated area. For example, without accurately correct the distortion,FIGS.11A to11Fsequentially illustrate that the illumination light source21generates the light beams to illumination light zones at positions from close to the optical axis to far away from the optical axis.FIG.11Gis a schematic diagram of the illumination light zones formed by all the light beams from the illumination light source21. Accordingly, the illumination light zone illuminated by the detection light from the illumination light source21close to the optical axis has a rectangular shape with the long sides in the horizontal direction. The illumination light zone illuminated by the detection light from the illumination light source21far away from the optical axis also has a rectangular shape with the long sides in the horizontal direction. So, a large area at the center of the designated area201will be an effective area among all of the designated areas201illuminated by the detection light. Therefore, the light field modulator10can significantly correct the distortion of the illumination light zone, reduce the energy loss, improve the lighting uniformity and the window efficiency of the detection module1.

It is worth mentioning that it should not be limited to the specific example of the light field modulator10of the detection module1. For example, the beam homogenizer11of the light field modulator10can use, but not limited to, a diffraction-based method to modulate the detection light, wherein the beam homogenizer11of the light field modulator10can be a DOE (Diffractive Optical Element) homogenizing layer.

Of course, the traditional homogenizing layer can modulate the detection light based on the scattering principle by adding chemical particles as scattering particles in the homogenizing base material, such that when the light passes through the homogenizing layer, the light will continuously refract, reflect and scatter in two media with different refractive indexes to produce optical homogenization effect. However, such homogenizer based on the scattering principle will inevitably absorb the light by the scattering particles, resulting in low light energy utilization. Furthermore, The light field is uncontrollable, it is difficult to flexibly form the specified light field distribution according to the specified requirements, and it is also prone to uneven light field and “hot spots”.

Preferably, according to the preferred embodiment of the present invention, as shown inFIG.9, the beam homogenizer11of the light field modulator10may be implemented as a light homogenizing layer based on the principle of light refraction, wherein the light field modulator10is divided into a plurality of the light modulation portions100. In one example, the number of the light modulation portions100of the light field modulator10is the same as the number of the illumination light sources21of the detection light source20, wherein the light modulation portions100are correspondingly set to the illumination light sources21in an one-to-one manner.

It should be understood that the homogenizing layer based on the principle of light refraction can also be based on a micro lens array for homogenizing light. In other words, the micro-concave-convex structure on the surface of the micro lens array will refract the light in different directions when passing through, so as to homogenize the light. Since such homogenization is entirely based on the refraction of light by the microstructure of its own surface, there is no light absorption by the scattering particles in the scattering type homogenization layer so as to increase the light energy utilization rate. As a result, by changing the shape and arrangement of the micro lens array, the diffusion angle, the space and energy distribution of the light field can be selectively adjusted.

Preferably, the number of the light modulation portions100of the light field modulator10is not equal to the number of the illumination light sources21of the detection light source20. In one example of the present invention, one light modulation portion100corresponds to at least two illumination light sources21. In another example of the present invention, at least two of the light modulation portions100correspond to one illumination light source21.

In one embodiment of the detection module1of the present invention, the illumination light source21of the detection light source20is configured to generate the detection light according to the predetermined time sequence and a predetermined rule. Specifically, the illumination light source21is configured to sequentially generate the detection light from left to right, right to left, top to bottom, bottom to top, counterclockwise or clockwise according to the predetermined time sequence in order to illuminate the corresponding designated area201. Furthermore, different illumination light sources21illuminate different designated areas201at different time, such that the detection of the entire detection area200will be completed after the end of the time period. It should be appreciated that in another example of the present invention, the illumination light sources21of the detection light source20can also be illuminated at the same time to increase the illumination power and expand the illumination range. If it is used in a distance measuring device, the detection distance can be increased.

For example, as shown inFIG.9, the detection light source20is constructed to have four illumination light sources21being evenly distributed and arrayed in a 2*2 manner. Correspondingly, the light field modulator10is constructed to have four light modulation portions100being evenly distributed and arrayed in a 2*2 manner. The illumination light sources21are configured to generate the detection light according to a predetermined time sequence and the predetermined rule to illuminate the designated areas201respectively. Alternatively, the illumination light source21of the detection light source20is configured to generate the detection light according to the predetermined timing, such that the illumination light source21is sequentially switched on to complete the illumination of the entire detection area200in one cycle.

It is worth mentioning that, as shown inFIG.12, the dimension of a single illumination light source21is set as W*H, wherein the horizontal and vertical distance between a center of one of the illumination light sources21and a center of the detection light source20are set as x and y respectively. A width gap between two adjacent illumination light sources21is set as GapWand a height gap between two adjacent illumination light sources21is set as GapH. Correspondingly, the diffusion angle of the light field modulator10is set as θDf-X, θDf-Y, and the focal length of the light field modulator10is set as fx, fy, then the field of view FOVx*FOVyof the illumination light source21are set as:

FOVx=arctan(x+W2fx)-arctan(x-W2fx)+θDf-XFOVy=arctan(y+W2fx)-arctan(y-W2fx)+θDf-Y

Since there is a gap formed between the adjacent illumination light sources21, obviously, there will also be a gap between the illumination light zones corresponding to the illumination light sources21, such that there will be a blind zone between the illumination light sources21to form the illumination light zones discontinuously (as shown inFIG.13). Therefore, if it is used in a three dimensional sensing device, mis-measurement will be happened.

Accordingly, since the diffusion angle of the light field modulator10of the present invention can be adjusted, the illumination light zones corresponding to the adjacent illumination light sources21will be partially overlapped. As a result, the entire light field will be uniform to eliminate any blind spot so as to reduce the sensitivity of the assembling and adjustment processes for the detection light source20. Preferably, the diffusion angle of the light field modulator10of the present invention is adjusted to continuously illuminate the entire detection area200as (as shown inFIG.14):

θDF-X>2*arctan⁡(GapW2⁢fx);θDF-Y>2*arctan⁡(GapH2⁢fy)

In one example, the light field modulator10of the present invention can optimize the illumination effect at the junction of each of designated areas to partially overlap between adjacent designated areas. Accordingly, an area of a single designated area is w*h, and the actual illumination light zone formed by the corresponding detection light from the illumination light source through the light field modulator10of the present invention is w1*h1, where w1≥w, h1≥h, such that the proportion of partially overlap portion can be determined in combination with the light configuration to ensure not only high energy utilization, but also the light uniformity. In addition, the sensitivity of the assembling and adjustment process can be reduced, and the blind spots can be eliminated.

Furthermore, if two directions of the illumination light source of the FoV are different, for example, a linear light projector can be used for illuminating a linear area, 70°*5°. Multiple optical elements will be used in a conventional method, wherein some of the optical elements are configured to compress a small angle direction of the divergence angle, some of the optical elements are configured to stretch a large angle direction of the divergence angle, and some of the optical elements are configured to control the energy distribution of the illumination light zone. Accordingly, one optical element will be used in the present invention, such that the present invention is a single device to provide a highly integrated structure with features of easy to install and adjust, small size, low cost and easy to control the light distribution.

It is worth mentioning that, for detection modules used for three-dimensional sensing equipment such as solid-state scanning lidar, the light field modulator10of the present invention can adjust the surface configuration of the microstructure of the beam homogenizer11, to compensate the lens shading at the receiver of the module. It should be understood that the lens shading refers to the center area of the image being brighter and the surroundings being darker (as shown inFIG.15) because of the mechanical structure of the module itself and the optical characteristics of the lens. Specifically, on one hand, during manufacturing and assembling the module, there will be certain process deflects to affect the object light propagation in the module. On the other hand, the lens can be embodied as a convex lens, wherein the converging ability at the center portion of the convex lens has a much larger that at its edge portion, such that the light intensity at the center of the receiving end is greater than that at the edge portion thereof (it is also called light attenuation). For the lens without distortion, the attenuation of the illumination around the image is set corresponding to the attenuation law of cos4θ. However, when considering the lens structure and the distortion, the attenuation of the illumination around the image may no longer follow the attenuation law of cos4θ. In fact, lens shading always exists in the ToF detection module.

Preferably, the present invention is configured to adjust the surface configuration of the microstructure on the beam homogenizer11of the light field modulator10, that is, optimizes each parameter in

z=cx⁢x2+cy⁢y21+1-(1+kx)⁢cx2⁢x2-(1+ky)⁢cy2⁢y2
for forming an illumination light field that matches with the receiving lens to compensate the shading of the receiving lens. Each unit in the sensor can receive relatively uniform luminance, wherein the signal-to-noise ratio of each light field of view is relatively balanced, such that the detection distance will not be affected due to the lens shading. For example,FIGS.16A and16Bare the light intensity distribution schematic diagram and light intensity distribution curve of the illumination light field formed by the light field modulator10of the present invention respectively.

It is worth mentioning that since cxand cyare the main factors of the lighting FOV, the larger the absolute values of cxand cyare, the larger the lighting FOV is. Correspondingly, the setting of kxand kyare main factors of the surface configuration of the micro lens, and further affects the energy distribution of the light field. As shown inFIG.17, |k1|<|k2|<|k3|<|k4|, the light intensity distribution curve correspondingly changes in a regular manner, i.e. the greater the absolute value of k is, the more the energy of the light field converges around. Therefore, the light field modulator10of the present invention is able to adjust the surface parameters of the microstructure and to modulate the light range and light energy distribution.

According to another aspect of the present invention, as shown inFIG.18, the present invention further provides a modulation method of the light modulator, comprising the following steps.

S100: Homogenize a light beam through at least one beam homogenizer element11of the light field modulator10.

S120: Deflect the light beam through a curved light transmitting substrate12of the light field modulator10, and adjust a divergence angle range of the light beam, wherein the curved light transmitting substrate12has at least one curving surface120, wherein the beam homogenizer11is correspondingly formed on the curving surface120of the curved light transmitting substrate12to configure the microstructure of the beam homogenizer11on the curving surface120of the curved light transmitting substrate12.

One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.

It will thus be seen that the objects of the present invention have been fully and effectively accomplished. The embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.