CN115654424A - Light homogenizing rod, light homogenizing rod module, light source system and parameter adjusting method - Google Patents
Light homogenizing rod, light homogenizing rod module, light source system and parameter adjusting method Download PDFInfo
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Abstract
The invention provides a light homogenizing rod, a light homogenizing rod module, a light source system and a parameter adjusting method. The light homogenizing rod at least comprises: the light homogenizing rod comprises a rod body, an incident plane and an emergent plane, wherein the rod body of the light homogenizing rod is a cylinder, a polygonal prism or a conical prism, the emergent plane is a frosted plane, and the surface of the emergent plane is in a diffuse reflection state so as to increase the emergent angle of light rays, so that the capability of light homogenizing and color mixing is improved, and the illuminance uniformity and the color uniformity of emergent light spots are uniformly distributed on a target plane; the light homogenizing rod, the light homogenizing rod module and the light source system have the advantages of low cost, easiness in implementation and high illuminance and color uniformity, can be widely applied to illumination of machine vision and microscopic imaging systems, and particularly have strict requirements on spectral components, illuminance and color distribution of illumination.
Description
Technical Field
The invention relates to the field of optical systems, in particular to a light homogenizing rod, a light homogenizing rod module, a light source system and a parameter adjusting method.
Background
LED light sources are gradually replacing incandescent lamps, energy saving lamps and other light sources in the general illumination field, and are also gradually replacing halogen lamps, mercury lamps and other light sources in machine vision and microscopic imaging systems. LED chips made of different semiconductor material processes can produce visible light of different spectra, as well as light in the near infrared and ultraviolet bands. The multispectral LED chip with high integration has the light modulation advantage incomparable to the traditional light source, avoids the realization form that the traditional multispectral light source adopts a single broad-spectrum light source and a multi-channel optical filter, and can realize the random combination of spectrum and light color.
In the optical design of a multispectral light source, a lens is mostly used for randomly combining the spectrum and the light color, so that the requirement of illumination is met, but the lens profile is too complex, is difficult to process, has higher implementation cost, and is difficult to realize uniform light mixing in a short distance. The invention provides a method for adjusting parameters of a light homogenizing rod based on a multi-channel LED chip, which can achieve the effect of uniform light mixing and color mixing in a short distance, compared with other optical modules, the light homogenizing rod is lower in manufacturing cost, and the light transmittance can reach 92% due to the common high molecular compound PMMA material, so that the light homogenizing rod is obviously superior to a diffuser with the same low cost.
Disclosure of Invention
The invention aims to provide a light guide and uniformizing system design realizing method for uniformly mixing light emitted by an LED light source with a plurality of different spectral channels; at the emitting end of the system, the light emitted by the LED chips with different spectral channels can be uniformly mixed, so that the illumination and the color of the emitted light are uniformly distributed on a target plane.
To achieve the above objects and other advantages in accordance with the present invention, a first object of the present invention is to provide a light distribution bar, comprising:
the rod body, the incident plane and the emergent plane; wherein the content of the first and second substances,
the rod body is a cylinder, a polygonal prism or a conical prism;
the incident surface is a smooth plane;
the emergent plane is a frosted plane, and the surface of the emergent plane is in a diffuse reflection shape, so that the emergent angle of the light is increased; the dodging rod realizes the effect of color mixing and dodging.
Preferably, the exit plane surface roughness is 0.2 μm Ra 0.6. Mu.m.
Preferably, the exit plane is sanded with 250-350 mesh sandpaper.
A second objective of the present invention is to provide a light homogenizing rod module, which is characterized in that the light homogenizing rod module includes at least two light homogenizing rods as described above, wherein the exit surfaces of the adjacent light homogenizing rods are closely attached to the incident surface, so that the light guided out by one light homogenizing rod directly enters into the other light homogenizing rod.
The third invention aims to provide a parameter adjusting method of a light homogenizing rod, which is characterized by comprising the following steps:
acquiring a first parameter group of target emergent light spot characteristic information to determine the cross-sectional shape of the target dodging rod, wherein the first parameter group at least comprises: the illumination uniformity ratio alpha of incident light, two side lengths h and w of the cross section of the target dodging rod, and the maximum aperture angle of the light incident into the dodging rod
A target uniformity of the excident light spot, wherein the target uniformity U comprises: target illuminance uniformity U i And target color uniformity U c ；
According to the illumination uniformity ratio alpha of incident light, two side lengths h and w of the cross section of the target dodging rod and the maximum aperture angle of the light incident into the dodging rod
Calculating the length L of the dodging rod d ，
Acquiring the roughness of an emergent plane of the dodging rod;
illumination uniformity U of emergent light spots of each single spectrum channel based on single spectrum channel LED chip simulation i ’；
Judging the illuminance uniformity U of the emergent light spot i ' whether greater than the target illuminance uniformity U i ；
If yes, the length L of the dodging rod d Is the target length L of the dodging rod under the condition of the current first parameter group m (ii) a If not, adjusting the first parameter group and repeating the steps until the uniformity U meeting the target illumination intensity is obtained i The first parameter group and the length L of the light homogenizing rod d ；
It is further preferred that the uniformity of illumination U of the exit spots when used in a single channel i ' greater than the target illuminance uniformity U i Then, the color uniformity U of the emergent light spots of the multispectral channels obtained based on the simulation of the multispectral channel LED chips is judged c Whether greater than a target color uniformity U c ；
If so, the first parameter group is the design parameter of the target dodging rod; if not, adjusting the first parameter set until obtaining the color uniformity U meeting the target c The first parameter group and the length L of the light homogenizing rod d 。
Preferably, the ratio of the uniformity of illuminance of the integrator bar to the length of the integrator bar is as follows:
preferably, the uniformity of illumination U of the excident light spot of each single spectral channel is simulated i ': obtaining the minimum value E of the illumination of the emergent facula min And maximum value E max Illuminance uniformity U of the emergent light spot i ’＝E min /E max 。
Preferably, the color uniformity U of the emergent light spot of the multi-spectral channel is simulated c ': obtaining the coordinates (u ', v') of the standard color points, the number M of sampling points on the surface of the emergent light spot, and the average value coordinates (u) of all the sampling points m ′,v m ') setting a constant k for color uniformity; where the subscript m is used to denote the average value.
Preferably, the number M of sampling points on the surface of the emergent light spot, and the average value coordinate (u ', v ') of all the sampling points are obtained according to the standard color point coordinates (u ', v m ′,v m '), the root mean square of the color point coordinate differences is calculated,
color uniformity U of the emergent light spot c ’＝100/(1+k·Δuv)。
Further preferably, the adjusting method further comprises: the device is used for judging whether the uniformity of the emergent light spots of the light homogenizing rod module consisting of a plurality of light homogenizing rods meets the uniformity of the target emergent light spots of the light homogenizing rod module; if yes, determining the number of the dodging rods; if not, adjusting the number of the dodging rods, simulating the uniformity of the emergent light spots, and repeating the steps; wherein the number includes two or more by number.
A fourth object of the present invention is to provide a light source system, comprising at least: the LED light source comprises an LED chip, a constant voltage source, a constant current source, a spectrum controller and a light guiding and homogenizing system;
the spectrum controller calculates driving signals of all spectrum channels to generate target spectrums;
the constant current source is connected with the spectrum controller and used for receiving the driving signals of the spectrum channels sent by the spectrum controller so as to configure the current amplitude of each channel;
the LED chip is driven by the constant current source;
the constant voltage source supplies power to the spectrum controller and the constant current source;
the light guide and uniformizing system comprises the above uniformizing rod or the above uniformizing rod module.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a light homogenizing rod based on an LED chip, which can achieve the effect of uniform mixed light and color mixing in a short distance, has better illumination uniformity and color uniformity, is lower in manufacturing cost compared with other optical modules, is made of common high polymer compound PMMA material, has the light transmittance reaching 92 percent, and is obviously superior to a diffuser with the same low cost.
Compared with the prior art, the light source system and the light homogenizing rod provided by the invention have the advantages of low cost, easiness in implementation and high illuminance and color uniformity, and can be widely applied to illumination of machine vision and microscopic imaging systems, particularly under the condition of strict requirements on spectral components, illuminance and color distribution of illumination.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to make the technical solutions of the present invention practical in accordance with the contents of the specification, the following detailed description is given of preferred embodiments of the present invention with reference to the accompanying drawings. The detailed description of the present invention is given in detail by the following examples and the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
FIG. 1 is a schematic diagram of a single integrator bar with a square cross-section according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a light homogenizing rod dual-rod module according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of another type of light homogenizing rod dual-rod module with another cross section according to an embodiment of the present invention;
FIG. 4 is a flowchart of a method for adjusting parameters of an optical integrator according to an embodiment of the present invention;
FIG. 5 is a flowchart of a method for adjusting parameters of an optical integrator according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a light source system according to an embodiment of the present invention;
in the drawings, 11, a light homogenizing rod with a square section; 12, an exit end face with diffusion effect; 20, an LED light source; 21, a dodging bar near the light source; 22, a light homogenizing bar remote from the light source; 31. 32, two cylindrical light homogenizing rods with frosted emergent planes; 41, a spectrum controller; 42, a multi-channel constant current source; 43, multispectral LED chip; 44, a light guide and uniformizing system; 45, a multi-channel constant voltage source.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.
Example 1
The present embodiment provides a light uniformizing bar, as shown in fig. 1, including:
a rod body, an incident plane, an exit plane, wherein
The rod body is a cylinder, a polygonal prism or a conical prism,
the incident plane is a smooth plane and the incident plane is a smooth plane,
the exit plane is the dull polish plane, and its surface forms diffuse reflection form for the exit angle of light increases, wherein, dodging stick realizes the even light effect of colour mixture.
Preferably, the rod body of the light homogenizing rod can be a cylinder, a polygonal prism or a tapered prism. Taking a square prism as an example, light rays enter from one end of the light homogenizing rod, are subjected to multiple Fresnel reflections on a symmetrical surface in the cylinder and then exit from the other end face, and the reflected light rays each time can be regarded as light rays generated by a new virtual light source; the cross section is square, regular hexagon and the like, and the shape meeting the 'mirror surface fit' has better light homogenizing effect.
It is further preferred that the cross-section also determines the shape of the excident light spot. In some embodiments, the exit spot of a prismatic integrator bar of square cross-section is shaped such that the region of most concentrated intermediate illumination is a square, while the surrounding regions have an unclear region of lower brightness due to stray light. Thus, the shape of the cross-section is chosen so that it covers the entire chip surface, both in terms of size and shape of the target spot.
Preferably, in order to achieve a better color mixing effect of the color lights emitted by the light homogenizing rods, the invention is based on the light mixing principle of a random scattering diffuser, namely, a random phase profile with some typical proportions is created at the front end of the light beam, so that the invention has the advantages of low cost and incoherent illumination system with a light source with a high divergence angle, and the emitting plane of each light homogenizing rod is ground into a frosted plane from a smooth plane, so that the emitting angle of the light rays is increased, and the different color lights are mixed more uniformly. In order to avoid excessive sanding resulting in too great a loss in light efficiency, the exit plane may be sanded using 250-350 mesh sandpaper to produce a surface roughness of 0.2 μm Ra 0.6. Mu.m. Among them, the exit plane is preferably sanded with 320-mesh sandpaper to a slightly frosted degree, i.e., haze, which is inversely proportional to light transmittance, and thus excessively high frosting degree is not recommended. As shown in fig. 1, 11 is a light homogenizing rod with a square cross section, and 12 is an exit plane with a diffusion effect.
The embodiment provides a dodging stick, change the exit plane of dodging stick into dull polish plane by smooth plane for the exit angle increase of light, in order to increase the number of reflections, thereby improve dodging ability, and then make different chromatic light mix more evenly, can realize obtaining the effect of even mixed light colour mixture in comparatively closely, compare in other optical module, dodging stick manufacturing cost is lower, the preparation of macromolecular compound PMMA material commonly used, the luminousness can reach 92%, is showing and is being superior to the diffuser of same low-cost.
Example 2
The embodiment provides a light homogenizing rod module, as shown in fig. 2, the light homogenizing rod module includes at least two light homogenizing rods as described above, and the light homogenizing rods are combined to form the light homogenizing rod module, wherein the exit surfaces of adjacent light homogenizing rods are tightly attached to the entrance surface without an air gap, so that light guided out by one light homogenizing rod directly enters the other light homogenizing rod; where 20 is the LED light source, 21 is the single bar closer to the light source, and 22 is the single bar further from the light source. The emergent end faces of the two single rods are both lightly frosted planes.
Preferably, the light homogenizing rod module is actually equivalent to that a plurality of random scattering diffusion plates are inserted into the middle of one light homogenizing rod, so that after the light with multiple spectrums is transmitted in a distance in the light homogenizing rod, the light is firstly diffused and then is continuously transmitted and mixed along the other light homogenizing rod. Compared with the design that a plurality of plane diffusers are inserted in the middle of a longer single-rod dodging rod, the multi-rod combined design provided by the embodiment only needs to splice a plurality of dodging rods with frosted end faces, so that the difficulty and the cost of the manufacturing process are greatly reduced.
Preferably, the rod bodies of the light homogenizing rods forming the light homogenizing rod module are the same or different, that is, the cross-sectional shapes of the exit surface and the incident surface of the adjacent light homogenizing rods can be different, and preferably, the exit surface of the light homogenizing rod with the same cross-sectional shape is closely attached to the incident surface.
Further preferably, the rod body of the light homogenizing rod can be a cylinder, a polygonal prism or a tapered prism. Taking a square prism as an example, light rays enter from one end of the light homogenizing rod, are subjected to multiple Fresnel reflections on a symmetrical surface in the cylinder and then exit from the other end face, and the reflected light rays each time can be regarded as light rays generated by a new virtual light source; as shown in fig. 3, 31 and 32 are two cylindrical light distributing rods with frosted exit planes.
Preferably, in order to further enhance the effect of uniform light and color mixing, the exit surfaces of the plurality of uniform light rods are tightly attached to the entrance surface, and no air gap is left for combination, so as to form a uniform light rod module, for example, the single rod size of the double-rod module is set to be 30mm, the exit surfaces of the double rods are both frosted planes, the distance between the target irradiation plane and the exit end surface of the module is 30mm, and calculation by using optical simulation software can prove that the mode of the double-rod combination has better illuminance and color uniformity than single-rod exit light. More specifically, when all four channels are illuminated, in a 10mm x 10mm spot range, the dual bar module achieves the result of: illuminance uniformity of 91.538% and color uniformity of 80.170%; the illumination and the color uniformity reach high indexes and can meet the requirements of microscopic imaging.
The even optical wand module that this embodiment provided uses a plurality of even optical wand combinations, and the even mixed colour of light effect of further reinforcing only needs the concatenation a plurality of even optical wand that have dull polish outgoing plane can, has easy realization, and is with low costs, and illuminance and colour degree of consistency are high advantage.
Example 3
The embodiment provides a method for adjusting parameters of a light bar, as shown in fig. 4, including the steps of:
s11: acquiring a first parameter group of target emergent light spot characteristic information, wherein the first parameter group at least comprises: the illumination uniformity ratio alpha of incident light, the two side lengths h and w of the cross section of the target dodging rod, and the maximum aperture angle of the light incident dodging rod
A target uniformity of the excident light spot, wherein the target uniformity U comprises: target illuminance uniformity U i And target color uniformity U c ；
S12: determining the cross section shape of the target dodging bar;
s13: according to the illumination uniformity ratio alpha of incident light, the two side lengths h and w of the cross section of the target light homogenizing rod and the maximum aperture angle of the light incident on the light homogenizing rod
Calculating the length L of the dodging rod d ，
S14: acquiring the roughness of an emergent plane of the dodging rod;
s15: illuminance uniformity U of emergent light spots of each single spectrum channel obtained based on single spectrum channel LED chip simulation i '; judging the illuminance uniformity U of the emergent light spot i ' whether or not greater than the target illuminance uniformity U i ；
S16: if yes, the length L of the dodging rod is equal to the length L of the dodging rod d Is the target length L of the dodging rod under the condition of the current first parameter group m (ii) a If not, adjusting a first parameter group and repeating the steps until the first parameter group which accords with the target illuminance uniformity and the length L of the dodging rod are obtained d ；
It is further preferred that the uniformity of illumination U of the excident light spot per single spectral channel is substantially uniform i ' greater than the target illuminance uniformity U i Then, the color uniformity U of the emergent light spots of the multispectral channels obtained based on the simulation of the multispectral channel LED chips is judged c ', whether greater than target color uniformity U c ；
If so, the first parameter group is the design parameter of the target dodging rod; if not, adjusting a first parameter group and repeating the steps until the first parameter group which accords with the target color uniformity and the length L of the dodging rod are obtained d 。
Preferably, the ratio of the uniformity of the illuminance of the light bar to the length of the light bar is expressed asThe following:
preferably, the illuminance uniformity U of the emergent light spot of each channel is judged i Whether greater than target illuminance uniformity U i Wherein the uniformity of the illumination of the emergent light spot is U i The calculation method of' is U i ’＝E min /E max ；E min And E max Respectively as the minimum value and the maximum value of the illumination intensity in the range of the light spots; uniformity of illumination U as each single channel in the LED chip i ' > 0.8, i.e. the uniformity U of the luminance of the emergent light spot of each channel i ' greater than target illuminance uniformity U i 。
Preferably, the target illuminance uniformity U i The value set to 0.8 is only a recommended value in this embodiment, and may be set according to actual situations, and this implementation is not particularly limited, where the illuminance uniformity is calculated by many methods, and different methods do not constitute a significant change to the method of the present invention.
Preferably, the color uniformity U of the multi-spectral channel emergent light spot obtained by the simulation c ': acquiring a second parameter set of emergent light spot characteristic information of a multi-spectral channel, wherein the second parameter set comprises: standard color point coordinates (u ', v '), the number M of sampling points on the surface of the emergent light spot, and the average value coordinates (u ' of all the sampling points) m ′,v m '), wherein subscript m is used to label the average, setting a constant k for color uniformity;
calculating a root mean square of the color point coordinate difference based on the second parameter set,
wherein the color uniformity U of the emergent light spot c ’＝100/(1+k·Δuv)。
Preferably, the number of the dodging rods of the dodging rod module is increased, so that emergent light spots have better illuminance and color uniformity, and the effect of mixed light and mixed color is improved; in some embodiments, at least two of the exit surfaces of the light uniformizing rods described in embodiment 1 are attached to the incident surface, so that the light guided out by one light uniformizing rod directly enters into another light uniformizing rod, and when the illuminance uniformity of each single channel and the color uniformity of light spots output by multiple channels simultaneously are determined, the parameter adjusting method of the light uniformizing rod is also adopted to determine whether the design requirements are met; if yes, determining the number of the dodging rods; if not, adjusting the number of the light homogenizing rods, simulating the uniformity of the emergent light spots, and repeating the steps until the number of the light homogenizing rods which accord with the target illuminance uniformity and the target performance uniformity is obtained;
preferably, the dodging effect of the dodging stick is related to its cross-sectional shape, which is determined by the shape of the area of maximum concentration of the illuminance in the middle of the excident light spot. The cross section is square, regular hexagon and the like, and the shape meeting mirror surface fitting has better light homogenizing effect.
It is further preferred that the cross-section also determines the shape of the excident light spot. The emergent light spot of the prismatic light homogenizing rod with a square cross section is in a shape that the area with the most concentrated middle illumination intensity is a square, and the surrounding area has an area with unclear boundary and low brightness due to the influence of stray light. The shape of the cross-section is therefore chosen such that it covers the entire chip surface, both in view of the chip size and in view of the shape of the target spot.
Preferably, the dodging effect of the dodging stick is also related to the rod length. Other conditions are the same, the longer the rod is, the more times the light is reflected in the cylinder, and the better the light homogenizing effect is. The good light homogenizing effect can be achieved within 10 reflection times. But after the reflection times reach a certain value, the length of the rod is increased, and the light homogenizing effect cannot be obviously increased. The emergent intensity will be weakened while the length of the rod is increased, the illumination efficiency will be reduced, and the size of the whole set of illumination system will be increased accordingly, so that the rod length cannot be pursued blindly when the illumination system is designed by using the light-homogenizing rod, and the length of the rod needs to be set according to actual needs.
Preferably, the size of the light homogenizing rod is designed mainly considering the illumination intensity and the color uniformity, and the light efficiency of the emergent light is considered. To ensure the color uniformity of the emergent light spot, the illumination uniformity of each channel of light emitted independently must be ensured. The relationship between the illuminance uniformity of the light homogenizing rod and the length thereof is as follows:
wherein L is d Which represents the length of the light homogenizing bar,
is the maximum aperture angle of the light incident on the integrator rod, and h and w represent the two side lengths of the integrator rod interface. The dimensionless parameter α is the ratio of the illuminance uniformity, i.e., corner illuminance/center illuminance; generally, alpha is more than or equal to 2.5, so that ideal uniformity can be achieved.
Preferably, in order to enable the color light emitted by the light homogenizing rod to have a better color mixing effect, the light homogenizing device is based on the light mixing principle of the random scattering diffuser, the emitting surface of each light homogenizing rod is changed from a smooth plane to a frosted plane, and the surface of each light homogenizing rod forms a diffuse reflection shape, so that the emitting angle of light is increased, and further different color lights are mixed more uniformly. In order to avoid too large light efficiency loss caused by excessive sanding, the emergent plane can be sanded by using sand paper of 250-350 meshes so as to generate surface roughness of Ra being more than or equal to 0.2 mu m and less than or equal to 0.6 mu m; wherein the roughness may also be expressed as frostiness or haze. The exit plane is preferably sanded with 320 grit sandpaper to a slightly frosted extent, i.e., haze, which is inversely proportional to light transmission, so excessively high frosting is not recommended.
The embodiment provides a parameter adjustment method for a light homogenizing rod, which realizes the effect of obtaining uniform mixed light and color mixing in a short distance, has lower cost and easier realization, improves the mixed light and color mixing effect of the light homogenizing rod, and is obviously superior to other optical system elements; the designed light-homogenizing rod with proper length can be widely used for illumination of machine vision and microscopic imaging systems, especially under the condition of strict requirements on spectral components, illumination intensity and color distribution of illumination.
Example 4
The embodiment provides a method for adjusting parameters of a light bar, as shown in fig. 5, including the steps of:
s21: acquiring a first parameter group of target emergent light spot characteristic information, wherein the first parameter group at least comprises: the illumination uniformity ratio alpha of incident light, the two side lengths h and w of the cross section of the target dodging rod, and the maximum aperture angle of the light incident dodging rod
A target uniformity of the excident light spot, wherein the target uniformity U comprises: target illuminance uniformity U i And target color uniformity U c ；
S22: determining the cross-sectional shape of the target dodging rod;
s23: according to the illumination uniformity ratio alpha of incident light, the two side lengths h and w of the cross section of the target light homogenizing rod and the maximum aperture angle of the light incident on the light homogenizing rod
Calculating the length L of the light homogenizing rod d ，
S24: acquiring the roughness of an emergent plane of the dodging rod;
s25: illumination uniformity U of emergent light spots of each single spectrum channel based on single spectrum channel LED chip simulation i ' judging to obtain the illuminance uniformity U of the emergent facula i ' greater than the target illuminance uniformity U i ；
S26: color uniformity U of emergent light spots of multispectral channels obtained based on simulation of multispectral channel LED chips c '; judging the color uniformity U of the emergent light spot c Whether greater than a target color uniformity U c ；
S27: if yes, the first parameter group is the design parameter of the target dodging rod; if not, adjusting the first parameter group and repeating the steps until the color uniformity U meeting the target is obtained i ' the first parameter set and the length L of the light homogenizing bar d 。
Further preferably, the color uniformity U of the emergent light spot of the multispectral channel is judged c ' whether greater than target color uniformity U c : uniformity of illuminance U of emergent light spot of each channel i ' greater than target illuminance uniformity U i When is U i ’≥U i Continuously judging the color uniformity U of the multi-channel emergent light spot c ' whether or not the target color uniformity U is large c . Wherein, the color uniformity can be calculated according to the following formula: u shape c ’＝100/(1+k·Δuv)，
k is a constant for setting the color uniformity range, and can be set according to actual conditions, and the embodiment is not particularly limited; Δ uv is a parameter characterizing color heterogeneity, in particular the root mean square value of the color coordinate difference
Wherein (u ', v') are the color coordinates of the CIE1976 standard, in further embodiments the color coordinates are the CIE1931 xy coordinate system. M is the number of samples on the illuminated surface (u) m ′,v m ') represents the average of all sample points, and the subscript m is used to mark the average. When the color uniformity of multiple channels is U c ' whether or not the target color uniformity U is large c When the color uniformity U is c And when the color uniformity of the emergent light spot is greater than or equal to 0.75, the color uniformity of the emergent light spot meets the design requirement.
Preferably, wherein the target color uniformity U c The setting of 0.75 is only a recommended value of the embodiment, and the specific numerical value may be set according to the actual situation, which is not specifically limited in this embodiment; in addition, as the color uniformity is more difficult to realize than the contrast uniformity, a reference value with a lower index than the contrast uniformity is adopted; the definition or judgment method of the color uniformity is variousThe use of different methods does not constitute a significant change to the method proposed by the present invention.
The embodiment provides a parameter adjustment method for a light homogenizing rod, which realizes the effect of obtaining uniform mixed light and color mixing in a short distance, has lower cost and easier realization, improves the mixed light and color mixing effect of the light homogenizing rod, and is obviously superior to other optical system elements; the light-homogenizing rod with proper length can be widely used for illumination of machine vision and microscopic imaging systems, especially under the condition of strict requirements on spectral components, illumination and color distribution of illumination.
Example 5
The present embodiment provides a light source system, which is designed based on the optical principle of a light homogenizing rod, as shown in fig. 6, and includes: the LED light source comprises an LED chip, a constant voltage source, a constant current source, a spectrum controller and a light guiding and homogenizing system; wherein the content of the first and second substances,
the spectrum controller 41 is a spectrum controller, and can be operated in an embedded microprocessor MCU or a CPU of a PC, and the spectrum controller 41 calculates driving signals of each spectrum channel to generate a target spectrum;
42 is a multi-channel constant current source, which is connected to the spectrum controller and is used for receiving the driving signal of each spectrum channel sent by the spectrum controller to configure the current amplitude of each channel;
43 is a multispectral LED chip driven by a multichannel constant current source;
44 is a light guide and uniformizing system, which comprises the single uniformizing rod or the uniformizing rod module;
and 45, a multi-channel constant-voltage source supplies power to the spectrum controller and the multi-channel constant-current source.
Preferably, the light guide and uniformizing system comprises the uniformizing bar of embodiment 1 or the uniformizing bar module of embodiment 2.
Preferably, based on an RGBW four-in-one LED chip, the size of the chip is 5mm multiplied by 5mm, and bare chips of four channels are transversely arranged; in an ideal state, the LED is a standard lambertian light source, and the maximum exit angle thereof is 120 °; the even optical system of leaded light includes an even optical stick module, even optical stick module includes two even optical sticks, and the size is 35mm, and two even optical stick exit surfaces are dull polish plane, and the exit end face of even optical stick module of target illumination plane distance is 30mm, and when four passageways all sent out light, at 10 mm's facula within range, the even optical system of leaded light realized: the uniformity of the illuminance of an emergent light spot of the light guide and uniformization system is 88.69 percent when a red light channel is singly started; the single green light channel is opened, and the illuminance uniformity of the emergent light spot of the light guide and dodging system is 89.60%; the uniformity of the illumination of the emergent light spots of the light guide and uniformizing system is 90.22 percent by singly opening the blue light channel; the uniformity of the illumination of the emergent light spots of the light guide and uniformization system is 86.07 percent by using a single white light channel; when the four-color light channel is fully opened, the illumination uniformity of the emergent light spots of the light guide and uniformization system is 92.18%; when the four-color light channel is fully opened, the color uniformity of the emergent light spots of the light guide and uniformization system is 80.384%; as shown in table 1:
TABLE 1
| Single-opening red channel | Single green channel | Single open blue channel | Single-opening white channel | Four-channel full-open | |
| Illuminance uniformity (%) | 88.69 | 89.60 | 90.22 | 86.07 | 92.18 |
| Color uniformity (%) | / | / | / | / | 80.384 |
As can be seen from Table 1, the illuminance uniformity and the color uniformity both reach very high indexes, so that the design of the light guide and uniformizing system can meet the requirements of microscopic imaging; in conclusion, the light homogenizing rod module has better illuminance uniformity and color uniformity than the emergent light of a single-rod light homogenizing rod.
The light source system provided by the embodiment has the advantages of low cost, easy realization and high illumination and color uniformity, and can be widely applied to illumination of machine vision and microscopic imaging systems, particularly under the condition of strict requirements on spectral components, illumination and color distribution of illumination.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments.
The foregoing is merely an example of the present specification and is not intended to limit one or more embodiments of the present specification. Various modifications and alterations to one or more embodiments described herein will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of the present specification should be included in the scope of claims of one or more embodiments of the present specification.
Claims (10)
1. A light homogenizing rod, comprising:
the rod body, the incident plane and the emergent plane; wherein the content of the first and second substances,
the rod body is a cylinder, a polygonal prism or a conical prism;
the incident surface is a smooth plane;
the emergent plane is a frosted plane, and the surface of the emergent plane is in a diffuse reflection shape, so that the emergent angle of the light is increased; wherein, the dodging stick realizes the effect of color mixing and dodging.
2. The light homogenizing rod of claim 1 wherein the exit plane surface roughness is 0.2 μm Ra 0.6 μm.
3. The light distribution rod of claim 2, wherein the exit plane is sanded with 250-350 mesh sandpaper.
4. An integrator module comprising at least two integrator rods according to any of claims 1 to 3, wherein the exit surfaces of adjacent integrator rods are in close contact with the entrance surface, so that light from one integrator rod directly enters into another integrator rod.
5. A parameter adjusting method of a light homogenizing rod is characterized by comprising the following steps:
acquiring a first parameter group of target emergent light spot characteristic information to determine the cross-sectional shape of the target dodging rod, wherein the first parameter group at least comprises: the illumination uniformity ratio alpha of incident light, two side lengths h and w of the cross section of the target dodging rod, and the maximum aperture angle of the light incident into the dodging rod
A target uniformity of the excident light spot, wherein the target uniformity U comprises: target illuminance uniformity U i And target color uniformity U c ；
According to the illumination uniformity ratio alpha of incident light, two side lengths h and w of the cross section of the target dodging rod and the maximum aperture angle of the light incident into the dodging rod
Calculating the length L of the light homogenizing rod d ，
Acquiring the roughness of an emergent plane of the dodging rod;
illumination uniformity U of emergent light spots of each single spectrum channel based on single spectrum channel LED chip simulation i ’；
Judging the illuminance uniformity U of the emergent light spot i ' whether or not greater than the target illuminance uniformity U i ；
If yes, the length L of the dodging rod d Is the target length L of the dodging rod under the condition of the current first parameter group m (ii) a If not, adjusting the first parameter group and repeating the steps until the uniformity U meeting the target illumination intensity is obtained i The first parameter group and the length L of the light homogenizing rod d 。
6. The method as claimed in claim 5, wherein the uniformity of illumination U of the emergent light spot of a single channel is determined i ' result is greater than the target illuminance uniformity U i The method also comprises the following steps: judging the color uniformity U of the emergent light spot of the multispectral channel obtained by simulating the LED chip based on the multispectral channel c Whether greater than a target color uniformity U c ；
If so, the first parameter group is the design parameter of the target dodging rod; if not, adjusting the first parameter set until obtaining the color uniformity U meeting the target c The first parameter group and the length L of the light homogenizing rod d 。
7. The method as claimed in claim 5, wherein the calculating the length of the light bar is performed by calculating the ratio of the uniformity of the illuminance of the light bar to the length thereof as follows:
8. the method as claimed in claim 5, wherein the uniformity of illuminance U of the emergent light spot of each single spectral channel is simulated i ': obtaining the minimum value E of the illumination of the emergent facula min And maximum value E max Wherein, U i ’＝E min /E max 。
9. The method as claimed in claim 6, wherein the color uniformity U of the emergent light spot of the analog multi-spectral channel is adjusted c ’：
Acquiring a second parameter set of emergent light spot characteristic information of a multi-spectral channel, wherein the second parameter set comprises: standard color point coordinates (u ', v'), number M of sampling points on the surface of the emergent light spot, and average value coordinates (u) of all sampling points m ′,v m ') setting a constant k for color uniformity;
calculating a root mean square of the color point coordinate difference based on the second parameter set,
the color uniformity U of the emergent light spot c ’＝100/(1+k·Δuv)。
10. A light source system, comprising at least: the LED light source comprises an LED chip, a constant voltage source, a multi-channel constant current source, a spectrum controller and a light guide and uniformizing system;
the spectrum controller calculates driving signals of all spectrum channels to generate target spectrums;
the constant current source is connected with the spectrum controller and is used for receiving driving signals of all spectrum channels sent by the spectrum controller so as to configure the current amplitude of each channel;
the LED chip is driven by the constant current source;
the constant voltage source supplies power to the spectrum controller and the constant current source;
wherein the light guide and dodging system comprises the dodging bar of the above claims 1-3 or the dodging bar module of claim 4.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211357233.8A CN115654424A (en) | 2022-11-01 | 2022-11-01 | Light homogenizing rod, light homogenizing rod module, light source system and parameter adjusting method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211357233.8A CN115654424A (en) | 2022-11-01 | 2022-11-01 | Light homogenizing rod, light homogenizing rod module, light source system and parameter adjusting method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117518336A (en) * | 2024-01-08 | 2024-02-06 | 中国科学院苏州生物医学工程技术研究所 | Ultrashort dodging system |
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- 2022-11-01 CN CN202211357233.8A patent/CN115654424A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117518336A (en) * | 2024-01-08 | 2024-02-06 | 中国科学院苏州生物医学工程技术研究所 | Ultrashort dodging system |
| CN117518336B (en) * | 2024-01-08 | 2024-04-12 | 中国科学院苏州生物医学工程技术研究所 | Ultrashort dodging system |
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