CN102914870A - Device for compensating optical focal plane based on wedge-shaped prism - Google Patents

Abstract

The invention discloses a device for compensating an optical focal plane based on a wedge-shaped prism. The device comprises an imaging optical system and a prober focal plane, and two right-angle wedge-shaped prisms between light paths of the imaging optical system and the prober focal plane; each right-angle wedge-shaped prism comprises a first wedge-shaped prism and a second wedge-shaped prism; inclined surfaces of the first right-angle wedge-shaped prism and the second right-angle wedge-shaped prism are adhered to form a parallel plane; a light beam sequentially passes through the first right-angle wedge-shaped prism and the second right-angle wedge-shaped prism, and is imaged at the position on the prober focal plane in a focusing manner; and the thickness of the parallel plane consisting of the two wedge-shaped prisms on an optical axis direction is changed by moving at least one of the two right-angle wedge-shaped prisms along the direction of the inclined surfaces of the first right-angle wedge-shaped prism and the second right-angle wedge-shaped prism, so that a light distance is changed for focusing. With the adoption of the device provided by the invention, the position of an image surface is continuously changed by moving the wedge-shaped prisms, so that the defocus compensation of the image surface can be realized.

Description

Device based on prism wedge compensate for optical focal plane

Technical field

The present invention relates to optical technical field, relate in particular to a kind of device based on prism wedge compensate for optical focal plane.

Background technology

Optical system when causing out of focus, need to be carried out defocusing compensation due to a variety of causes (such as zoom process, perhaps temperature variation) to system.And existing optical focal plane compensating machanism usually general be the mechanical type focus control, control the position of one or more pieces optical elements by focus control, defocusing amount is eliminated at the interval that changes optical element.But can affect the aberration of system when compensating out of focus by mobile lens.

Summary of the invention

In view of above-mentioned analysis, the present invention aims to provide a kind of device based on prism wedge compensate for optical focal plane, in order to address the above problem.

Purpose of the present invention mainly is achieved through the following technical solutions:

A kind of device based on prism wedge compensate for optical focal plane comprises: imaging optical system and detector focal plane, and two right angle prism wedges between the light path of described imaging optical system and described detector focal plane;

Described right angle prism wedge comprises the first prism wedge and the second prism wedge, and the inclined-plane of described the first right angle prism wedge and described the second right angle prism wedge fits together, and both is inverted to coordinate to consist of a parallel flat;

Light beam passes described the first right angle prism wedge and described the second right angle prism wedge successively, and at place, described detector focal plane focal imaging, move at least one in two described right angle prism wedges by the bevel direction along described the first right angle prism wedge and described the second right angle prism wedge, change on optical axis direction the thickness of the parallel flat that two prism wedges form and then change light path and focus.

Preferably, described the first prism wedge and described the second prism wedge shape and size are identical.

Preferably, described the first right angle prism wedge comprises the first faceted pebble, the second faceted pebble and the first inclined-plane;

Described the second right angle prism wedge comprises the 4th faceted pebble, the 5th faceted pebble and the second inclined-plane;

Described the first faceted pebble parallels with described the 5th faceted pebble, and described the first faceted pebble is all vertical with optical axis direction with described the 5th faceted pebble;

Described the second faceted pebble and described the 4th faceted pebble parallel, and described the second faceted pebble is all parallel with optical axis direction with described the 4th faceted pebble.

Preferably, described the first right angle prism wedge also comprises the 3rd faceted pebble, and described the 3rd faceted pebble is parallel with described the second faceted pebble, and described the second faceted pebble and described the 3rd faceted pebble are positioned at the two ends of described the first faceted pebble;

Described the second right angle prism wedge also comprises the 6th faceted pebble, and described the 6th faceted pebble is parallel with described the 4th faceted pebble, and described the 4th faceted pebble and described the 6th faceted pebble are positioned at the two ends of described the 5th faceted pebble.

Preferably, the length of the intersection of described the first faceted pebble and described the second faceted pebble is Y, Y 〉=X ₀, t ₁Be the length on another limit of described the second faceted pebble, t ₁Scope be

t ₂Length for the limit of corresponding described the 6th faceted pebble in another limit of described the second faceted pebble;

The length on another limit of described the first faceted pebble is X, and described right angle prism wedge along the movably distance of maximum on this limit is $\±{\mathrm{\Δx}}_{\max }=\frac{{\±\mathrm{nd}}_{\max }}{(n-1)\tan \mathrm{\α}},$ $X>X_0+\frac{{2\mathrm{nd}}_{\max }}{(n-1)\tan \mathrm{\α}};$

The angle that described the second faceted pebble is corresponding is wedge angle α, and the angle of total reflection of described prism wedge is The scope of described wedge shape corner angle α is:

And t ₁-t ₂=Xtan α;

The length on the limit of described the 6th faceted pebble that the length on another limit of described the second faceted pebble is corresponding with it and be T, T=t ₁+ t ₂, described parallel flat along the maximal value of the thickness change of optical axis direction is ${\mathrm{\&Delta;T}}_{\max }=\frac{{2d}_{\max }n}{n-1},$ In when, skew occuring $T<L-L_1-\frac{{2d}_{\max }n}{n-1};$

Wherein, L is the distance between optical system and detector focal plane, L ₁Be the distance between described parallel flat and described detector focal plane, X ₀That distance between described parallel flat and described detector focal plane is L ₁Light beam clear aperture on described first faceted pebble of Shi Suoshu the first right angle prism wedge, n is the refractive index of described right angle prism wedge, d is the defocusing amount of optical system focal plane, ± d _maxBe the maximum defocus amount of optical system focal plane, Δ x be described right angle prism wedge along the rate of travel perpendicular to optical axis direction, Δ T be described right angle prism wedge along the rate of travel that is parallel to optical axis direction, β is picture side's aperture angle of optical system.

Beneficial effect of the present invention is as follows:

A kind of device based on prism wedge compensate for optical focal plane provided by the invention, by adjusting the position of two prism wedges, make the section thickness difference of the parallel flat of prism wedge composition, thereby the change light path reaches the defocusing compensation to system, the present invention can change image planes position generation by mobile prism wedge continuously, be that the defocusing compensation amount can realize continuous variation, do not need other elements in mobile original system, can when not changing system aberration, image planes not carried out defocusing compensation as far as possible.

Other features and advantages of the present invention will be set forth in the following description, and becoming apparent from instructions of part perhaps understood by implementing the present invention.Purpose of the present invention and other advantages can realize and obtain by specifically noted structure in the instructions of writing, claims and accompanying drawing.

Description of drawings

Fig. 1 is the device schematic diagram of the prism wedge compensate for optical focal plane of the embodiment of the present invention;

Fig. 2 is the schematic perspective view of the first prism wedge of the embodiment of the present invention;

Fig. 3 is the schematic perspective view of the second prism wedge of the embodiment of the present invention;

The 1-optical system, 2-the first prism wedge, 3-the second prism wedge, 4-detector focal plane, 5-the first faceted pebble, 6-the second faceted pebble, 7-the 3rd faceted pebble, 8-the first inclined-plane, 9-the second inclined-plane, 10-the 4th faceted pebble, 11-the 5th faceted pebble, 12-the 6th faceted pebble.

Embodiment

Specifically describe the preferred embodiments of the present invention below in conjunction with accompanying drawing, wherein, accompanying drawing consists of the application's part, and is used for explaining together with embodiments of the present invention principle of the present invention.For clear and simplification purpose, when it may make theme of the present invention smudgy, with illustrating in detail of known function and structure in omission device described herein.

Embodiment 1

The embodiment of the present invention provides a kind of device based on prism wedge compensate for optical focal plane, referring to Fig. 1-3, comprising:

Imaging optical system 1 and detector focal plane 4, and two right angle prism wedges on the light path between described imaging optical system and described detector focal plane; Specifically as shown in Figure 1.

described prism wedge comprises the first prism wedge 2 and the second prism wedge 3, described the first prism wedge 2 and described the second prism wedge 3 shapes and size are identical, the inclined-plane of described the first prism wedge 2 and described the second prism wedge 3 fits together, both be inverted to coordinate and consist of a parallel flat, light beam passes described the first prism wedge 2 and described the second prism wedge 3 successively, and at described detector focal plane 4 place's focal imagings, move at least one in two prism wedges by the bevel direction along described prism wedge, change the thickness of the parallel flat of two prism wedge compositions on optical axis direction and then change light path and focus, as shown in Figure 1, the imaging point of dotted line is the imaging point before adjusting, the imaging point of solid line is the imaging point after adjusting by prism wedge.

As shown in Fig. 2 and 3, described the first prism wedge 2 comprises the first faceted pebble 5, the second faceted pebble 6, the 3rd faceted pebble 7 and the first inclined-plane 8; As AA in figure ₁D ₁D is described the first faceted pebble, and ABCD is described the second faceted pebble 6, A ₁B ₁C ₁D ₁Be the 3rd faceted pebble 7, BCC ₁B ₁Be described the first inclined-plane 8.

Described the second prism wedge 3 comprises the 4th faceted pebble 10, the 5th faceted pebble 11, the 6th faceted pebble 12 and the second inclined-plane 9, as H in figure ₁E ₁EH is described the second inclined-plane 9, E ₁F ₁G ₁H ₁Be described the 4th faceted pebble 10, G ₁F ₁FG is described the 5th faceted pebble 11, and EFGH is described the 6th faceted pebble 12.

Light beam enters described the first prism wedge 2 along described the first faceted pebble 5, passes described the first inclined-plane 8 and described the second inclined-plane 9, passes from described the 5th faceted pebble 11 of described the second prism wedge 3.

Described the second faceted pebble 6 is all parallel with optical axis direction with described the 4th faceted pebble 10.Described the first faceted pebble 5 is all vertical with optical axis direction with described the 5th faceted pebble 11.

The length Y of described the first faceted pebble 5 and the intersection of described the second faceted pebble 6, i.e. the length Y of the AD Y 〉=X that should satisfy condition ₀

By the maximum focusing amount ± d of optical system _maxCan draw, the vertical range of the transportable maximum of prism wedge is

The minimum overall length of prism wedge should be not less than

The AA of described the first faceted pebble 5 ₁The length on limit is X, and is wherein said

If optical system requires the maximum focusing amount that parallel flat can be realized to be ± d _max, by the character of parallel flat, can draw parallel flat and along the maximum that the thickness of optical axis direction need to change be

When described prism wedge is offset, the satisfying with T of the limit of described the 6th faceted pebble that another limit of the second faceted pebble 6 is coupled

Be the length of AB+EF $T<L-L_1-\frac{{2d}_{\max }n}{n-1};$

Angle between the first faceted pebble 5 of described the first prism wedge 2 and described the first inclined-plane 8 is α, the key groove α of prism wedge is larger, its focusing amount d that produces when same skew occurs can be larger, but total reflection occurs when preventing that light beam from passing through prism wedge, and the incident angle on prism wedge inclined-plane should be less than its angle of total reflection α _maxCan obtain its angle of total reflection by snell law

N is the refractive index of prism wedge material, and β is picture side's aperture angle of optical system.The angle α of prism wedge should satisfy

And AB-A ₁B ₁=Xtan α.

The thickness of the webbing of described the first prism wedge is that the second faceted pebble is along the length of side AB of optical axis direction; The thickness of featheredge is that the 3rd faceted pebble is along the length of side A of optical axis direction ₁B ₁A ₁B ₁A should satisfy condition ₁B ₁〉=0.By front AB-A ₁B ₁=Xtan α, AB+EF=T, The thickness A B that can obtain the first prism wedge 2 webbings should satisfy condition $X\tan \mathrm{\&alpha;}<\mathrm{AB}<\frac{1}{2}L-\frac{1}{2}{L}_1-\frac{d_{\max }n}{n-1}+\tan \mathrm{\&alpha;}.$

Wherein, L is the distance that optical system arrives the detector focal plane, i.e. rear cut-off distance; L ₁Distance for parallel flat range finder focal plane; L ₀The horizontal range of placing other element headspaces in mechanical hook-up and focus planardetector assembly, L ₁〉=L ₀X ₀To be L when parallel flat to detector focal plane distance ₁The time, the light beam clear aperture on first prism wedge the first faceted pebble; N is the refractive index of prism wedge material; D is the defocusing amount of optical system focal plane; ± d _maxMaximum defocus amount for optical system focal plane; Δ x is that prism wedge is along the rate of travel perpendicular to optical axis direction; Δ T is that prism wedge is along the rate of travel that is parallel to optical axis direction.

The side of described the first prism wedge 3 and described the second prism wedge 4 can be right-angled trapezium, can be also complete right-angle triangle, works as A ₁B ₁＞0 is right-angled trapezium, works as A ₁B ₁=0 is right-angle triangle.

As known from the above, when optical system zoom amount be d _maxThe time, the first prism wedge and the second prism wedge are relatively moved in the direction perpendicular to optical axis Relatively move along the direction that is parallel to optical axis

Image plane focusing can be completed focusing to the detector focal plane.

In sum, a kind of device based on prism wedge compensate for optical focal plane that the embodiment of the present invention provides, by adjusting the position of two prism wedges, make the prism wedge section thickness different, thereby change light path and reach the defocusing compensation to system, the present invention can change image planes position generation by mobile prism wedge continuously, be that the defocusing compensation amount can realize continuous variation, do not need other elements in mobile original system, can when not changing system aberration, image planes not carried out defocusing compensation as far as possible.

The above; only for the better embodiment of the present invention, but protection scope of the present invention is not limited to this, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement are within all should being encompassed in protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claims.

Claims (5)

1. the device based on prism wedge compensate for optical focal plane, is characterized in that, comprising: imaging optical system and detector focal plane, and two right angle prism wedges between the light path of described imaging optical system and described detector focal plane;

Described right angle prism wedge comprises the first prism wedge and the second prism wedge, and the inclined-plane of described the first right angle prism wedge and described the second right angle prism wedge fits together, and both is inverted to coordinate to consist of a parallel flat;

Light beam passes described the first right angle prism wedge and described the second right angle prism wedge successively, and at place, described detector focal plane focal imaging, move at least one in two described right angle prism wedges by the bevel direction along described the first right angle prism wedge and described the second right angle prism wedge, change on optical axis direction the thickness of the parallel flat that two prism wedges form and then change light path and focus.

2. device according to claim 1, is characterized in that, described the first prism wedge and described the second prism wedge shape and size are identical.

3. according to claim 2 or 3 described devices, is characterized in that,

Described the first right angle prism wedge comprises the first faceted pebble, the second faceted pebble and the first inclined-plane;

Described the second right angle prism wedge comprises the 4th faceted pebble, the 5th faceted pebble and the second inclined-plane;

Described the first faceted pebble parallels with described the 5th faceted pebble, and described the first faceted pebble is all vertical with optical axis direction with described the 5th faceted pebble;

Described the second faceted pebble and described the 4th faceted pebble parallel, and described the second faceted pebble is all parallel with optical axis direction with described the 4th faceted pebble.

4. device according to claim 3, is characterized in that,

Described the first right angle prism wedge also comprises the 3rd faceted pebble, and described the 3rd faceted pebble is parallel with described the second faceted pebble, and described the second faceted pebble and described the 3rd faceted pebble are positioned at the two ends of described the first faceted pebble;

Described the second right angle prism wedge also comprises the 6th faceted pebble, and described the 6th faceted pebble is parallel with described the 4th faceted pebble, and described the 4th faceted pebble and described the 6th faceted pebble are positioned at the two ends of described the 5th faceted pebble.

5. device according to claim 4, is characterized in that,

The length of the intersection of described the first faceted pebble and described the second faceted pebble is Y, Y 〉=X ₀, t ₁Be the length on another limit of described the second faceted pebble, t ₁Scope be t ₂Length for the limit of corresponding described the 6th faceted pebble in another limit of described the second faceted pebble;

The length on another limit of described the first faceted pebble is X, and described right angle prism wedge along the movably distance of maximum on this limit is ${\&PlusMinus;\mathrm{\&Delta;x}}_{\max }=\frac{{\&PlusMinus;\mathrm{nd}}_{\max }}{(n-1)\tan \mathrm{\&alpha;}},$ $X>X_0+\frac{{2\mathrm{nd}}_{\max }}{(n-1)\tan \mathrm{\&alpha;}};$

The angle that described the second faceted pebble is corresponding is wedge angle α, and the angle of total reflection of described prism wedge is The scope of described wedge shape corner angle α is:

And t ₁-t ₂=Xtan α;

The length on the limit of described the 6th faceted pebble that the length on another limit of described the second faceted pebble is corresponding with it and be T, T=t ₁+ t ₂, described parallel flat along the maximal value of the thickness change of optical axis direction is ${\mathrm{\&Delta;T}}_{\max }=\frac{{2d}_{\max }n}{n-1},$ In when, skew occuring $T<L-L_1-\frac{{2d}_{\max }n}{n-1};$

Wherein, L is the distance between optical system and detector focal plane, L ₁Be the distance between described parallel flat and described detector focal plane, X ₀That distance between described parallel flat and described detector focal plane is L ₁Light beam clear aperture on described first faceted pebble of Shi Suoshu the first right angle prism wedge, n is the refractive index of described right angle prism wedge, d is the defocusing amount of optical system focal plane, ± d _maxBe the maximum defocus amount of optical system focal plane, Δ x be described right angle prism wedge along the rate of travel perpendicular to optical axis direction, Δ T be described right angle prism wedge along the rate of travel that is parallel to optical axis direction, β is picture side's aperture angle of optical system.

Images