CN2339999Y - Device for regulating illumination intensity distribution of imaging apparatus - Google Patents

Abstract

The utility model relates to a device for regulating illumination intensity distribution of an imaging apparatus, which comprises a lens assembly and an aperture diaphragm. The lens assembly is at least composed of a lens. The aperture diaphragm is provided with a light-transmitting part. The imaging apparatus is characterized in that an imaged object forms an image after passing through the lens assembly and the aperture diaphragm, an image of the aperture diaphragm formed by the lens assembly between the aperture diaphragm and the imaged object of the whole imaging device is a pupil, and a light regulating diaphragm is longitudinally arranged on the front or the rear of the first piece of lens of the lens assembly. The light regulating diaphragm causes the image of the imaged object to have a uniform luminance from the different points of the imaged object to the different zones of the light-transmitting part of the pupil.

Description

A kind of adjustment Illumination Distribution device of imaging device

The utility model relates to a kind of adjustment Illumination Distribution device of imaging device, particularly relates to the adjustment Illumination Distribution device of the more uniform imaging device that a kind of illumination that makes imaging can distribute.

When using peripheral equipment scanner (SCANNER) the scanning picture of computer or literal in the past, the situation brighter in the middle of the image that is presented has, that both sides are darker, this situation also can occur in the application such as camera of optical device, the camera of wide-angle lens particularly, this is because the cos biquadratic effect (cosine fourth Law) of light source in imaging device causes, as shown in Figure 1, 2, make uniformly light-emitting thing (line source) 10 after general imaging device 11 imagings 12, brighter in the middle of the Illumination Distribution of imaging place presents, both sides are darker.Shown in the figure: E: as illumination, E0: the illumination on optical axis, E (x=0)=E0, Φ: visual angle, hi: image height, si: image distance, Φ=tan ^-1Hi/2/si θ: incident angle, θ=tan ^-1| x|/si.

Revise this illumination cosine biquadratic effect (the imaging Illumination Distribution state brighter just, that both sides are darker), the general practice has two kinds:

One, modification is shone by the brightness of the light source of imaging thing:

(1) block light source in the middle of partly brightness, make illumination in the middle of imaging place level off to the illumination of both sides.

(2) add the illumination of intense light source both sides, make the illumination of the imaging place both sides illumination in the middle of can leveling off to.

Though this method has certain effect, but make cost increase.

Two, as shown in Figure 3, add a slice with respect to the shading baffle plate 13 of incident angle θ horizontally set between by imaging thing (line source) 10 and picture 12 with the restriction luminous flux, and the height (centre is higher, both sides are lower) that utilizes this shading baffle plate 13 is adjusted the number of restriction luminous flux, because it is higher in the middle of this shading baffle plate 13, can stop more light, both sides are lower, can allow more light pass through, and use and revise cosine biquadratic effect.But this method still has following shortcoming: this shading baffle plate 13 is with plastic rubber ejaculate molding, and the tolerance of ejaculation is big, makes that the shape of this shading baffle plate 13 is inaccurate.

The purpose of this utility model is to provide a kind of method and device of adjustment Illumination Distribution of imaging device, can be modified to the cosine biquadratic effect of picture, makes the Illumination Distribution of picture more even.

The technical solution of the utility model is to provide a kind of device of adjustment Illumination Distribution of imaging device, it is characterized in that: by first lens front in lens combination, the back vertically is provided with the light tight light modulation diaphragm of a tool proper width, and in an optical device, put the aperture diaphragm of a light-permeable, by by difference on the imaging thing toward people's pupil center when looking, this light modulation diaphragm or its picture can cover the printing opacity zones of different partly of this people's pupil, just this light modulation diaphragm or its look like to cover the position of people's pupil, can move with viewing angle is different, and reach by the imaging thing after passing through this lens combination and this aperture diaphragm, the Illumination Distribution of picture is a specific function, particularly distributes uniformly.

Technical solutions of the utility model also are to provide following supplementary features:

The shape of this light modulation diaphragm is to cooperate by the Illumination Distribution of imaging thing, this aperture diaphragm printing opacity shape partly and the Illumination Distribution of the picture desiring to reach.

A kind of device of adjustment Illumination Distribution of imaging device, comprise a lens combination and an aperture diaphragm of forming by at least one lens, this aperture diaphragm has a printing opacity partly, this imaging device is by the imaging behind this lens combination of process and this aperture diaphragm of imaging thing with one, at the aperture diaphragm of being formed by the lens combination between the imaging thing of this aperture diaphragm and whole imaging device similarly is people's pupil

More comprise first lens light modulation diaphragm afterwards that is located at this lens combination.

The shape of this light modulation diaphragm is to cooperate by the Illumination Distribution of imaging thing, this aperture diaphragm printing opacity shape partly and the Illumination Distribution of the picture desiring to reach.

The utility model compared with the prior art advantage and good effect is very obvious, and advantage of the present utility model as shown from the above technical solution is:

One, the utility model is by in the front of first lens of lens combination or the pre-position of back, vertically be provided with one light tight and have a light modulation diaphragm of preset width, make the position that the picture of this light modulation diaphragm or light modulation diaphragm covers people's pupil to move with viewing angle is different, reach by the imaging thing by after this lens combination and this aperture diaphragm imaging, as Illumination Distribution be uniform.

Two, the cosine biquadratic effect of light modulation diaphragm correction light source of the present utility model is more in the past than the simple shape that adopted the shading baffle plate, more convenient on making, must not increase extra cost of parts, and must not do too many modification to original mechanism, and only utilized the shape of shading baffle plate to match with shading baffle plate correction cosine biquadratic effect with aperture diaphragm printing opacity shape partly in the past, do not utilize the position that the shading baffle plate covers people's pupil to move with viewing angle is different, so the utility model is than in the past with shading baffle plate correction cosine biquadratic effect Cui more.

Be elaborated below by most preferred embodiment and accompanying drawing device to the adjustment Illumination Distribution of a kind of imaging device of the present utility model, in the accompanying drawing:

Fig. 1 is that the uniformly light-emitting thing is after general imaging device imaging, at the Illumination Distribution figure of imaging place.

Fig. 2 is the thing-as concerning synoptic diagram of the general imaging device of Fig. 1.

Fig. 3 is generally in order to revise the shading baffle plate synoptic diagram of cos biquadratic effect.

Fig. 4 is the utility model than the thing of Cui embodiment-as concerning schematic side view.

Fig. 5 is that the part of Fig. 4 is amplified schematic top plan view.

Fig. 6 is that equivalent people's pupil and light modulation location of aperture concern synoptic diagram.

(incident angle θ is between 0 and tan ^-1Between (W RS/2/d).)

Fig. 7 is that equivalent people's pupil and light modulation location of aperture concern synoptic diagram.

(incident angle θ is between tan ^-1(W RS/2/d) and tan ^-1((r-W RS/2)

/ d) between).

Fig. 8 is that equivalent people's pupil and light modulation location of aperture concern synoptic diagram.

(incident angle θ is between tan ^-1((r-W RS/2)/d) and tan ^-1((r+W RS

/ 2)/d).

Fig. 9 is attenuation rate α ≡ Tcos ⁴θ and incident angle θ concern synoptic diagram.

Figure 10 is that equivalent people's pupil and light modulation location of aperture concern synoptic diagram.

(incident angle θ=0)

As shown in Figure 4, the device of the adjustment Illumination Distribution of imaging device of the present utility model, comprise a lens combination 2 of forming by at least one lens, an aperture diaphragm 3 and a light modulation diaphragm 6, this lens combination 2 comprises first lens 20 and last lens 21, set lens numbers can be decided according to device requirement between these first lens 20 and last lens 21, in the present embodiment, between these first lens 20 and last lens 21, other lenses is not set, only this aperture diaphragm 3 is set between the two at it, this aperture diaphragm 3 be in the optical device except light modulation diaphragm 6, the element of restriction luminous flux maximum, this aperture diaphragm 3 has a printing opacity part 30, this printing opacity part 30 is circular, square, rectangle, triangle or other shapes, be to adopt circle in the present embodiment, this imaging device make one by imaging thing 4 through the 3 back imagings of this lens combination 2 and this aperture diaphragm, and the aperture diaphragm of being formed at first lens 20 by between the imaging thing 4 of this aperture diaphragm 3 and whole imaging device 3 similarly is to adopt people's pupil 31.

Pre-position in the front of first lens 20 of this lens combination 2 is provided with this lighttight light modulation diaphragm 6, this light modulation diaphragm 6 is to adopt vertical setting, and has a predetermined width, the shape of this light modulation diaphragm 6 must cooperate by the luminous Illumination Distribution of imaging thing 4 (line source), this aperture diaphragm 3 printing opacities partly 30 shape and the institute picture desiring to reach Illumination Distribution and designed, the shape of this light modulation diaphragm 6 is employing rectangles in the present embodiment.

When this light modulation diaphragm 6 be provided in a side of these first lens 20 and by imaging thing 4 between the time, then looked toward these people's pupil 31 central points by difference on the imaging thing 4 by this, this light modulation diaphragm 6 all covers the zones of different of the printing opacity part 310 of this people's pupil 31, that is to say that the position that this light modulation diaphragm 3 covers people's pupil 31 can move with viewing angle is different, can reach this by imaging thing 4 by behind this lens combination 2 and this aperture diaphragm 3, the Illumination Distribution of picture is uniformly, just can reach the cosine biquadratic effect that is modified to picture.

As shown in Figure 5, be that the part of Fig. 4 is amplified schematic top plan view, wherein:

EP (Entrance Pupil): be people's pupil 31;

RS (Rectifying Stop): be light modulation diaphragm 6;

D: be spacing for RS and EP, h0: by the height of imaging thing 4;

θ: be incident angle, just the angle of this chief ray 40 and optical axis 41 (Optical Axis).Should be considered as pointolite by each point on the imaging thing 4, its light that sends has only facing to this people's pupil 31 opens luminous energy in the solid angle by optical device, and in this light cone, this road light by these people's pupil 31 central points is chief ray (Chief Ray) 40;

φ: be the angle of two light, these two light are to be sent by the object point on this optical axis 41, and pass through the edge of this people's pupil 31.

The utility model can reach the cosine biquadratic effect that is modified to picture really than the device of Cui embodiment, just flatten the purpose of illumination side's cloth, as Fig. 6,7, the 8th, concern synoptic diagram in the position of these light modulation diaphragm 6 locational equivalent people's pupils 60 and light modulation diaphragm 6 among Fig. 4, when incident angle θ not simultaneously, logical light area is also inequality: one, at first, cooperate shown in Fig. 5,6 r=Z RStan φ/2

(r, as shown in Figure 6)

As 0＜θ＜tan ^-1W RS/2/d

Calculate right half of photic zone area

A1=πr ²/2-[(r ²sinψ·cosψ)+r ²(π/2-ψ)]，

Calculate left half of photic zone area

A2=πr ²/2-[(r ²sinψ′·cosψ′)+r ²(π/2-ψ′)]

So, always lead to light area A=A1+A2 two, follow, cooperate shown in Fig. 5,7 r=Z RStan φ/2

Work as tan ^-1W RS/2/d＜θ＜tan ^-1((r-W RS/2)/d)

Calculate right half of photic zone area

A1=πr ²/2-[(r ²sinψ·cosψ)+r ²(π/2-ψ)]，

Calculate left half of photic zone area

A2=πr ²/2+[(r ²sinψ′·cosψ′)+r ²(π/2-ψ′)]

So, shown in always logical light area A=A1+A2 three, cooperation Fig. 5,8, r=Z RStan φ/2

Work as tan ^-1((r-W RS/2)/d)＜θ＜tan ^-1((r+W RS/2)/d)

Total logical light area A=π r ²-[r ²ψ '-r ²Sin ψ ' cos ψ ']

From the above, because former logical light area is π r ², therefore comparing with former logical light area, present transmittance is T=A/ π r ², adding cosine biquadratic effector, the Illumination Distribution that arrives image planes at last is

Ei ≡ EoTcos ⁴θ k, wherein:

Eo: by the Illumination Distribution of imaging thing, K: constant.

Other defines attenuation rate α ≡ Tcos ⁴θ

If d=2.91mm, r=1mm, W RS=0.436mm, the graph of a relation of attenuation rate α and incident angle θ then, as shown in Figure 9, the ratio of its maximal value and minimum value is 1.04, and the attenuation rate α=cos that in the past caused because of cosine biquadratic effect ⁴The maximal value of θ (T=1) and the ratio of minimum value then are 1.38, therefore, by the use of this light modulation diaphragm 6 of the present utility model, can reach the cosine biquadratic effect that is modified to picture, the purpose of leveling Illumination Distribution.

Shown in Fig. 4,5, the utility model first is by the pre-position in first lens 20 front of this lens combination 2 than Cui embodiment, a rectangular light tight light modulation diaphragm 6 vertically is set, and this light modulation diaphragm 6 has a predetermined width, cooperate shown in Fig. 5,10, and the cooperation triangle formula, calculate 23 numbers such as certain position (Z RS) of this light modulation diaphragm 6 and width (W RS):

One, when incident angle θ is 0, the light that only sends seen at the imaging (temporarily not considering the influence of this light modulation diaphragm 6) for light source A place, light is subject to the size (people's pupil 31 diameters are W EP) of this people's pupil 31, one light cone can only be arranged by optical device lens combination 2, locate in certain position of this light modulation diaphragm 6 (Z RS), the sectional area size of light cone is A EP.

∴ φ is very little

∴tanφ=sinφ=W?EP/L0=φ,r=Z?RS·tan(φ/2)

A?EP=(Z?RS·W?EP/L0·1/2) ²·π=r ²·π

If two make θ=0 and θ=Φ=tan ^-1During h0/2/L0 (h0 is an object height), the attenuation rate α ≡ Tcos of the two ⁴θ equates.

(1) arrange earlier the position of this light modulation diaphragm 6, when making θ=Φ, this light modulation diaphragm 6 can not become barriers of luminous flux just, at this moment

T(θ=Φ)=1

Obtain cot φ=W RS/2/ (Z max-Z RS) by Fig. 5

Therefore, W RS=2 (Z max-Z RS) cot φ ... (A formula)

Z max=L0h0/ (ho+W EP) wherein, cot φ=h0/2/Z max

(2) then, control the width W RS of this light modulation diaphragm 6, so that

α=T(θ=0)=T(Φ)·cos ⁴Φ=cos ⁴Φ

As shown in figure 10, when θ=0, the sectional area of light modulation diaphragm shading is A RS

A?RS(W?RS·(r+rsinω)/2)·2=W?RS·r(1+sinω)

R=Z RStan (φ/2)=Z RSW EP/2L0 wherein

sinω=[1-(W?RS/2) ²/r ²] ^1/2

∴T=1-A?RS/A?EP

=1-W?RS{1+[1-(W?RS/2) ²/r ²] ^1/2}/

(Z?RS·W?EP/2L0·π)

=COS ⁴Φ ... (B formula)

Three, by (A), (B) two formulas, can draw W RS and Z RS

(1) puts (B) formula earlier in order

Z?RS·W?EP/2L0·π(1-COS ⁴Φ)

=W?RS{1+[1-(W?RS·L0/(Z?RS·W?EP)) ²] ^1/2}

Make Y=Z RS/W RS, Ki=W EP π (1-COS ⁴Φ)/and 2L0, K2=WEP/L0

Be inserted in (B) formula, then (K1Y-1) ²=1-1/ (K2 ²Y ²)

←K1 ²K2 ²Y ⁴-2K1K2 ²Y ³+1=0

← Y=γ 1, γ 2, γ 3, γ 4 (obtaining four roots) get separating for Y wherein

As Y=γ, Z RS=γ W RS then

(2) substitution (A) formula W RS=2 (Z max-Z RS) cot φ

Can obtain W RS=2Z maxcot φ/(1+2rcot) can be obtained this light modulation diaphragm 6 by above-mentioned calculating certain position Z RS, and the width W RS of this light modulation diaphragm 6, as long as after lighttight this light modulation diaphragm 6 set, just can make by this by difference on the imaging thing 4 toward this people's pupil 31 when looking, this light modulation diaphragm 6 all covers people's pupil 31 printing opacities zones of different partly of this aperture diaphragm 3, reach this by imaging thing 4 by after this lens combination 2 and 3 imagings of this aperture diaphragm, the Illumination Distribution of picture is uniformly, is modified to the cosine biquadratic effect of picture effectively.

Of the present utility model second is that lighttight light modulation diaphragm 61 is located at pre-position between this first lens 20 backs and the image planes 5 (about this second certain position calculation than light modulation diaphragm among the Cui embodiment than Cui embodiment, to calculate as after, and not in addition with graphic signal, in case of necessity can three examine shown in Figure 4), make when by this by imaging thing 4 on difference toward these people's pupil 31 centers when looking, the picture of light modulation diaphragm 61 covers partly 310 zones of different of these people's pupil 31 printing opacities, just this light modulation diaphragm 61 can move with viewing angle is different as 62 positions of covering people's pupil 31, reach by this this by imaging thing 4 by after this lens combination 2 and 3 imagings of this aperture diaphragm, the Illumination Distribution of picture is a specific function, particularly distributes uniformly.

One, as shown in Figure 4, see through first lens 20 imaging than the light modulation diaphragm of having tried to achieve among the Cui embodiment 6 with first, and by following formula in the hope of second the position than the light modulation diaphragm 61 of Cui embodiment:

-1/P+1/q=1/f1 wherein, f1: the focal length that is first lens 20.

P: be first the distance than 6 to first lens 20 of light modulation diaphragm of having tried to achieve among the Cui embodiment.

Q: be first the distance that looks like first lens 20 than the light modulation diaphragm 6 of having tried to achieve among the Cui embodiment.(P, q are to be initial point with first lens 20, be left+, be to the right-, f1 is during for poly-lens, f1＞0, and when f1 is divergent lens, f1＜0)

If the image space of being tried to achieve is between these last lens 21 and first lens 20, then this light modulation diaphragm 61 is arranged at this, otherwise, first picture than this light modulation diaphragm 6 of having tried to achieve among the Cui embodiment must be seen through last lens 21 imaging once more, in the hope of the position of this light modulation diaphragm 61, its formula is as follows:

-1/ (q-L)+1/q '=1/f2 wherein, q ': be the distance between the picture 62 that sees through the light modulation diaphragm 61 after these first lens 20 and last lens 21 imagings and last lens 21, symbol definition is identical with P, q.

F2: the focal length of these last lens 21, symbol definition is identical with f1.

L: the distance of first lens 20 and last lens 21.

Two, width

Through these first lens 20, its magnification M1=q/P,

Through these last lens 21, its magnification M2=q '/(q-L),

Therefore, overall amplification is M=M1M2, if former light modulation diaphragm width of having tried to achieve is W RS, and the second light modulation diaphragm width than Cui embodiment is W ' RS

(1) only try to achieve second the light modulation diaphragm 61, then be than Cui embodiment with these first lens 20 imaging:

W′RS=W?RS·M1

(2) with these first lens 20 and second lens 21 imaging and try to achieve second than Cui embodiment the light modulation diaphragm, then be:

W′RS=W?RS·M1·M2。

By above calculating, can obtain second certain position and the width W ' RS than the light modulation diaphragm of Cui embodiment, and original first just become second picture 62 than the light modulation diaphragm 61 of Cui embodiment than the light modulation diaphragm of trying to achieve among the Cui embodiment, as long as after should lighttight light modulation diaphragm 61 setting, just can make by this by difference on the imaging thing 4 toward this people's pupil 31 when looking, this light modulation diaphragm 61 as 62 people's pupil 31 printing opacities zoness of different partly of all covering this aperture diaphragm 3, reach this by imaging thing 4 by after this lens combination 2 and 3 imagings of this aperture diaphragm, the Illumination Distribution of picture is uniformly, effectively is modified to the cosine biquadratic effect of picture.

Claims (4)

1. the device of the adjustment Illumination Distribution of an imaging device, comprise a lens combination and an aperture diaphragm of forming by at least one lens, this aperture diaphragm has a printing opacity partly, this imaging device is by the imaging behind this lens combination of process and this aperture diaphragm of imaging thing with one, picture people pupil at the aperture diaphragm of being formed by the lens combination between the imaging thing of this aperture diaphragm and whole imaging device is characterized in that:

Also comprise one and a light modulation diaphragm in first lens front of this lens combination, this light modulation diaphragm is vertical setting, and when by this by the imaging thing on difference when looking toward this people's pupil center, can cover this people's pupil printing opacity zones of different partly.

2. the device of the adjustment Illumination Distribution of imaging device according to claim 1 is characterized in that:

The shape of this light modulation diaphragm is to cooperate by the Illumination Distribution of imaging thing, this aperture diaphragm printing opacity shape partly and the Illumination Distribution of the picture desiring to reach.

3. the device of the adjustment Illumination Distribution of an imaging device, comprise a lens combination and an aperture diaphragm of forming by at least one lens, this aperture diaphragm has a printing opacity partly, this imaging device is by the imaging behind this lens combination of process and this aperture diaphragm of imaging thing with one, the aperture diaphragm of being formed by the lens combination between the imaging thing of this aperture diaphragm and whole imaging device similarly be people's pupil, it is characterized in that:

More comprise first lens light modulation diaphragm afterwards that is located at this lens combination.

4. as the device of the adjustment Illumination Distribution of imaging device as described in the claim 3, it is characterized in that:

The shape of this light modulation diaphragm is to cooperate by the Illumination Distribution of imaging thing, this aperture diaphragm printing opacity shape partly and the Illumination Distribution of the picture desiring to reach.

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