CN103412352B - Lobster eye lens adopting tail end light absorbing coating to inhibit stray light generation - Google Patents

Abstract

The lobster eye lens for inhibiting stray light to generate using end light-absorbing coating,Belong to bionics optics technical field,To solve the prior art, that there are the efficiencies of light energy utilization is low,The coating of front does not have the problem of practical application,Lobster eye lens of the invention are made of many minim channel pipes,Each channel is made of four trapezoidal reflecting walls,When light passes through micro channel array,Only when light reflects odd times in the horizontal and vertical directions,Light emits to focal point,Effectively imaging,The present invention carries out coating treatment to horizontal and vertical conduit wall end,So that even reflection veiling glare is absorbed,And meet horizontal direction coated length Vertical direction coated length The cross coke arm of cross picture point can effectively be inhibited in this way, while eliminating the spuious ambient noise light in image planes, greatly improve the focusing quality of lobster eye lens.

Description

End light-absorbing coating is adopted to suppress the lobster eye lens of parasitic light generation

Technical field

The present invention relates to a kind of lobster eye lens adopting end light-absorbing coating to suppress parasitic light generation, obvious inhibiting effect can be had to the burnt arm of the cross of cross picture point, eliminate spuious to the ground unrest light in image planes simultaneously, this will improve the focusing quality of lobster eye lens greatly, belongs to bionics optics technical field.

Background technology

Lobster eye lens is made up of some micro-channel tubes 1, as shown in Figure 1, each micro-channel tubes 1 has oneself optical axis, micro-channel tubes 1 is the positive quadrangular frustum pyramid shaped of α in drift angle, four isosceles trapezoid side inner walls of positive truncated rectangular pyramids are reflecting wall 2, the limit, four, bottom surface of positive truncated rectangular pyramids forms the outer rim of micro-channel tubes 1, the outer rim of each micro-channel tubes 1 is positioned on the sphere that radius is R, each micro-channel tubes 1 axis is each orientation of same spheroid, the radius of pitch orientation, the lobster eye lens that each micro-channel tubes 1 is formed is a spheroid, certain spherical crown of this spheroid is also a kind of lobster eye lens, be called spherical crown lobster eye lens.

The imaging process of lobster eye lens is as follows, see shown in Fig. 1, Fig. 2, incident light divides three kinds of situations by lobster eye lens, and the first situation is that incident light a, b are through reflecting wall 2 primary event, converge on the cross focal line of sphere focal plane 3, image device 4 is formed cross picture.The second situation be incident light c through neighboring reflection wall 2 liang of secondary reflections, converge in the center of the cross focal line on sphere focal plane 3, image device 4 form desirable picture point.The third situation is that incident light d reflection is directly transmitted on sphere focal plane 3, formation background light on image device 4.Further, lobster eye lens is imaged as real image.A lobster eye lens has some optical axises, the object point of any position and the line of lobster eye lens center O can regard optical axis as, and light finally all can converge on sphere focal plane 3, so lobster eye lens only has aberration on axle, specifically spherical aberration on axle, without oblique spherical aberration.Because lobster eye lens is imaged as reflective, so without any aberration.Complete lobster eye lens is a spheroid, so, can Large visual angle imaging, visual field reaches 360 °.Lobster eye lens can be used in x-ray imaging, has the feature of single structure, and structure is simple, compact, lightweight.

But in lobster eye simulation optical system, there is obvious parasitic light, and kind is many, comprise bias light and disperse parasitic light, and when light reflects odd-times in level and vertical direction, light reflection is to focus place, when light reflects odd-times in the horizontal or vertical directions, and when reflecting even-times in the other direction, the two-arm that reflection ray will be turned back to cross focal line, become and disperse parasitic light, when light all reflects even in the two directions or directly will become background light through light during lobster eye lens micro-channel tubes without reflection, reduce focus contrast.

Prior art utilizes the method for two ends light-absorbing coating to absorb parasitic light and bias light, but it is low to there is the efficiency of light energy utilization, and front end coating is without shortcomings such as actual work use.

Summary of the invention

Utilize the method for two ends light-absorbing coating to absorb parasitic light and bias light and the efficiency of light energy utilization existed is low to solve prior art, front end coating is without the problem of actual work, a kind of lobster eye lens adopting end light-absorbing coating to suppress parasitic light generation is proposed, the generation of lobster optics of the eye system internal reflection parasitic light can be suppressed, alleviate the impact of parasitic light on image quality, can the efficiency of light energy utilization be improved simultaneously, light-absorbing coating is effectively played a role.

In order to solve the problem, technical scheme of the present invention is as follows:

End light-absorbing coating is adopted to suppress the lobster eye lens of parasitic light generation, be made up of multiple micro-channel tubes 1, each micro-channel tubes 1 is the positive quadrangular frustum pyramid shaped of α in cone apex angle, four isosceles trapezoid side inner walls of positive truncated rectangular pyramids are reflecting wall 2, the outer rim of each micro-channel tubes 1 is positioned on the sphere that radius is R, in space, the label of any micro-channel tubes 1 is (i, j)

The length formula of the light-absorbing coating 5 on the reflecting wall 2 of the horizontal direction of (i, j) micro-channel tubes 1 of described lobster eye lens is: ${L^j}_{\mathrm{coating}}=\frac{(R-t)\mathrm{\α}}{\tan \left((j+N-1)\mathrm{\α}\right)},$

The length formula of the light-absorbing coating 5 on the reflecting wall 2 of the vertical direction of (i, j) micro-channel tubes 1 of described lobster eye lens is: ${L^i}_{\mathrm{coating}}=\frac{(R-t)\mathrm{\α}}{\tan \left((i+N-1)\mathrm{\α}\right)},$

In formula: t is channel depth, N is order of reflection, and R is the radius of micro-channel tubes 1 outward flange place sphere, and α is the cone apex angle of micro-channel tubes 1, and i represents horizontal coordinate, and j represents vertical coordinate.

The invention has the beneficial effects as follows: the application of the invention describe when adopting the lobster eye lens of end light-absorbing coating to focus on, effectively can suppress the veiling glare formed by multiple reflections, also have certain inhibiting effect to cross picture.Carry out modeling comparative analysis by using Stray light analysis software to show, under the prerequisite not reducing gonglion illumination, use the lobster eye lens of end absorber coatings significantly can suppress the veiling glare level of the burnt arm of cross, thus the contrast of signal to noise ratio (S/N ratio) and image can be significantly improved.

Accompanying drawing explanation

Fig. 1 is lobster eye lens imaging system schematic diagram.

Fig. 2 is that incident light wave is by lobster eye lens imaging optical path schematic diagram.

Fig. 3 is the schematic diagram that in lobster eye lens micro-channel tubes, incident parallel light produces the rear outgoing of odd reflection.

Fig. 4 is the schematic diagram that after parallel input light produces even reflection in lobster eye lens micro-channel tubes, outgoing becomes parasitic light.

Fig. 5 is that in lobster eye lens micro-channel tubes, parallel input light part produces odd reflection, and after the reflection of part even, outgoing becomes the schematic diagram of bias light.

Fig. 6 is the end light-absorbing coating structural representation of the present invention.

Fig. 7 is lobster eye lens structural parameters schematic diagram.

In Fig. 8, a is existing lobster eye lens illuminance of image plane design sketch; B is existing lobster eye lens illuminance of image plane curve map.

Fig. 9 is that the present invention adopts end light-absorbing coating to suppress the lobster eye lens design sketch of parasitic light generation.

In Figure 10, a is that the present invention adopts end light-absorbing coating to suppress the lobster eye lens illuminance of image plane design sketch of parasitic light generation; B is that the present invention adopts end light-absorbing coating to suppress the lobster eye lens illuminance of image plane curve map of parasitic light generation.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further details.

As shown in Fig. 1, Fig. 7, Fig. 9, a kind of lobster eye lens adopting end light-absorbing coating to suppress parasitic light generation, be made up of some micro-channel tubes 1, each micro-channel tubes 1 is the positive quadrangular frustum pyramid shaped of α in cone apex angle, four isosceles trapezoid side inner walls of positive truncated rectangular pyramids are reflecting wall 2, the outer rim of each micro-channel tubes 1 is positioned on the sphere that radius is R, according to the center subtended angle of the vertical outer reflecting walls 2 of each micro-channel tubes 1 corresponding cone apex angle α multiple carries out vertical dimension numbering to micro-channel tubes 1, and the channel unit label of positioned proximate central axis is 1, by that analogy.In like manner, the center subtended angle of outer reflecting walls 2 in the horizontal direction corresponding α multiple forms the label of another dimension, and the channel unit label of positioned proximate central axis is 1.Unified label (i, j) can be adopted to represent to channel unit any in space like this, then the channel unit label of the micro-channel tubes 1 of positioned proximate central axis is (1,1).Light-absorbing coating 5 length formula on vertical direction on reflecting wall 2 corresponding to (i, j) channel unit is:

${L^j}_{\mathrm{coating}}=\frac{(R-t)\mathrm{\α}}{\tan \left((j+N-1)\mathrm{\α}\right)}$ ①，

The length formula of the light-absorbing coating 5 on the reflecting wall 2 in the horizontal direction of same channel unit (i, j) is:

${L^i}_{\mathrm{coating}}=\frac{(R-t)\mathrm{\α}}{\tan \left((i+N-1)\mathrm{\α}\right)}$ ②，

In formula: t is channel depth, N is order of reflection, and R is the radius of micro-channel tubes 1 outward flange place sphere, and α is the cone apex angle of micro-channel tubes 1, and i represents horizontal coordinate, and j represents vertical coordinate.

The optical absorption coating that end light-absorbing coating 5 adopts is pitch-dark, can absorb the luminous energy of 90% ~ 99%.

Analysis is carried out so that the present invention to be described to the reflection direction in single micro-channel tubes on a direction below.

Suppose that object point at infinity, the light arriving lobster eye lens is parallel rays.When parallel rays reflects through micro-channel tubes 1 inwall, three kinds of reflected version can be produced: all light produces the rear outgoing of odd-times reflection; Whole light produces the rear outgoing of even reflection; Part light produces odd-times (or even-times) reflection, outgoing after all the other light generation even-times (or odd-times) reflection simultaneously.The odd even time change of this order of reflection is the function at parallel rays and micro-channel tubes 1 spatial relation β angle, sees Fig. 3 to Fig. 5, and the odd even time change corresponding to this order of reflection of micro-channel tubes 1 determined is continuous print.Simultaneously, trace is carried out known by the coboundary light of the parallel beam to incidence channel and lower limb light, the veiling glare that all even reflections produce all is produced by lower reflecting wall 2, and the microchannel reflecting wall 2 also just near central vision in micro-channel tubes 1 produces.Therefore, absorber coatings process can be done to the part of reflection even veiling glare, use efficiency light absorbing material to be attached to the corresponding reflecting part of micro-channel tubes 1 inwall, reach the object eliminating even veiling glare.

The light-absorbing coating 5 length L using following relational expression to carry out on the reflecting wall 2 of each micro-channel tubes 1 determines, as shown in Figure 7:

round numbers, determines lower limb light reflection number of times; 3.

N _upper=N _lower+ 1 determines coboundary light reflection number of times; 4.

N=[N _upper; N _lower] get even number, calculate parasitic reflection number of times; 5.

determine the length of absorber coatings; 6.

Wherein, t is the micro-channel tubes degree of depth, and α is micro-channel tubes cone apex angle, and R is the radius of micro-channel tubes 1 outer rim place sphere.γ is outgoing parallel rays and reflecting wall 2 angulation, as shown in Figure 6,

γ＝（β+N）α ⑦

β＝(j-1)α ⑧

7., 8. formula is brought into formula 6. in, show that formula is 1..

In like manner can release formula 2., namely try to achieve the length L of the end light-absorbing coating 5 on reflecting wall 2.

Embodiment 1:

According to above-mentioned analysis, ray machine modeling software FRED is used to carry out modeling to a lobster eye lens model, and to the comparative analysis using above-mentioned two kinds of coatings to carry out veiling glare inhibition.Structural parameters are as follows:

Channel depth t=20mm; Passage cone apex angle α=1 °; Outer rim radius of curvature R=102mm; Angle of half field-of view θ=15 °; While guarantee is compared with Large visual angle, there is good encircled energy at this lobster eye lens of image planes l=47.5mm place.

Hypothesis institute uses light-absorbing coating to giving tacit consent to the absorptivity that light wave has 100% simultaneously, and before and after comparison use coating, the illumination analysis that obtains is as follows:

As shown in Fig. 8 a, b, be the Illumination Distribution figure that common lobster eye lens is formed, in order to increase the contrast of image, having carried out to image process of taking the logarithm, therefrom can find out, the veiling glare of common lobster eye lens is cross distribution.

Carry out the process of latter end coating to above-mentioned lobster eye lens and eliminate veiling glare, light-absorbing coating length is as shown in the table:

Due to during multiple reflections from the unit that vertical label is 6, so end light-absorbing coating also from No. 6 unit arrange.Due to the symmetry of lobster eye lens, horizontal direction does same coating process.

As shown in Figure 9, for the present invention adopts end light-absorbing coating to suppress the lobster eye lens part-structure of parasitic light generation.

As shown in Figure 10 a, b, be the illumination figure using the lobster eye lens of end coating process to be formed in image planes, therefrom can find out, use end coating effectively can suppress the veiling glare formed by multiple reflections.Veiling glare dissipation region reduces, and the burnt arm of cross foreshortens to about 6CM from original 17CM.

Obviously can find out the veiling glare level using end light-absorbing coating can effectively reduce lobster eye lens, thus the contrast of signal to noise ratio (S/N ratio) and image can be significantly improved.

Claims (2)

1. adopt end light-absorbing coating to suppress the lobster eye lens of parasitic light generation, be made up of multiple micro-channel tubes (1), each micro-channel tubes (1) is the positive quadrangular frustum pyramid shaped of α in cone apex angle, four isosceles trapezoid side inner walls of positive truncated rectangular pyramids are reflecting wall (2), the outer rim of each micro-channel tubes (1) is positioned on the sphere that radius is R, and in space, the label of any micro-channel tubes (1) is (i, j), it is characterized in that

Light-absorbing coating (5) length formula of the horizontal direction reflecting wall (2) of (i, j) micro-channel tubes (1) of described lobster eye lens is: ${L^j}_{\mathrm{coating}}=\frac{(R-t)\mathrm{\α}}{\tan \left((j+N-1)\mathrm{\α}\right)},$

Absorber coatings (5) length formula of the vertical direction reflecting wall (2) of (i, j) micro-channel tubes (1) of described lobster eye lens is: ${L^i}_{\mathrm{coating}}=\frac{(R-t)\mathrm{\α}}{\tan \left((i+N-1)\mathrm{\α}\right)},$

In formula, t is channel depth, and N is order of reflection, and R is the radius of micro-channel tubes (1) place sphere, and α is the cone apex angle of micro-channel tubes (1), and i represents horizontal coordinate, and j represents vertical coordinate;

Cone apex angle α multiple corresponding to the center subtended angle of the vertical outer reflecting walls (2) of each micro-channel tubes (1) carries out vertical dimension numbering to micro-channel tubes (1), the cone apex angle α multiple corresponding to the subtended angle of center of outer reflecting walls (2) forms horizontal dimensions label in the horizontal direction, in space, the label of any micro-channel tubes (1) is (i, j), channel unit label is (1,1) is positioned proximate central axis.

2. employing end light-absorbing coating according to claim 1 suppresses the lobster eye lens that parasitic light produces, and it is characterized in that, the material of described absorber coatings (5) is pitch-dark.