CN101111794B - Optical system and corresponding optical element - Google Patents

Abstract

The invention relates to an optical system (1100) comprising: - at least one source of illumination (30) designed to produce an illuminating beam (35) ; and - at least one imager (34) able to produce an imaging beam (37) when illuminated by the said illuminating beam; the said system being characterized in that it further comprises : - collimating means (1101) for collimating the said illuminating beam; and - at least one optical element (1101) comprising, on a first surface, means for redirecting part of the said illuminating beam towards the said imager, so as to illuminate the said imager and for adapting the shape of the said beam to suit the said imager.

Description

Optical system and corresponding optical element

Technical field

The present invention relates to field of image projection.More particularly, the present invention relates to a kind of illuminator of imager of the video projector that is used for front projection type or back projection type.

Background technology

According to background technology,, use illuminator 10 illumination imagers 11 as with reference to illustrated in fig. 1.

Usually, illuminator 10 comprises:

Lighting source 100 with ellipsoidal reflector;

Colour wheel 107;

Rectangular light guide 102; With

The system of several relay lenss 104 to 106.

In the along of the ellipsoidal reflector of light source 100,101 illuminations of lighting source 100 usefulness light beams are arranged on the colour wheel 107 of rectangular light guide 102 porch.Rectangular light guide 102 is used for converting the circular cross section of illuminating bundle to rectangular cross section, thereby makes light beam spatially relatively evenly.

The outgoing beam of photoconduction 102 is imaged on the imager 11 through relay lens system, has at least two relay lenss here, but normally three or four, and lighting source is (telecentric) of telecentric iris preferably also.

If imager 11 is trade marks is DMD (digital micro-mirror device) type of Texas Instrument

; Then, between illuminator 10 and imager 11, TIR prism 12 is set for split beam.If imager 11 is transmission-type LCD (Liquid Crystal Display) types; Then just do not need TIR prism 12; If perhaps imager 11 is LCOS (Liquid Crystal On Silicon) types, then replace TIR prism 12 by PBS (Polarizing Beam Splitter).

The major defect of this background technology is the quantity (generally being a photoconduction and at least two relay lenss) of optical module and the numerical aperture (from f2/2.5 to f/3.0) that with regard to efficient, obtains superperformance; Thereby applied strict condition to projecting lens, the structure of the projecting lens in the especially shallow depth projection appearance (shallow depthprojector).

Summary of the invention

An object of the present invention is to eliminate these shortcomings of background technology.

More particularly, an object of the present invention is to reduce the quantity of optical module required in the image projector.

For this reason, the present invention proposes a kind of optical system, it comprises:

At least one lighting source, it is designed to produce the illuminating bundle that focuses on the focal region; With

At least one imager, it can produce imaging beam when being thrown light on by said illuminating bundle;

Said system is characterized in that it further comprises:

Calibrating installation is used to calibrate the said illuminating bundle from said focal region; With

At least one optical element; It comprises following apparatus on the first surface of said at least one optical element; This device is used for said imager is arrived in the said illuminating bundle break-in of part, thereby throws light on said imager, and is used to make the shape of said light beam and said imager to match.

Advantageously, said calibrating installation is calibrated said illuminating bundle in the following manner, and promptly said light beam is from the value of its optical axis deviation absolute value less than 6 °.

According to specific characteristic, said first surface reflects said illuminating bundle.

According to another characteristic, calibrating installation comprises the lens that at least one separates with optical element.

According to preferable feature, said optical element comprises and said first surface opposing second surface that said second surface part at least forms said calibrating installation.

Advantageously, said second surface is sphere or aspheric.

According to specific characteristic, said first surface reflects said illuminating bundle.

Preferably, said first surface converts said illuminating bundle the light beam of similar rectangular cross section to, and said imager is a rectangle.

Preferably; Said first surface comprises facet; Each facet can both be with the said illuminating bundle break-in of part to said imager; Be formed for thus the throwing light on light beam of break-in of said imager, the light beam of said break-in is relevant with all facets, and all facets have and are fit to the global shape that matches with said imager.

Advantageously, each said facet all is the plane.

Preferably, each said facet all is rectangle or foursquare.

According to a favourable characteristic, optical system comprises that colour wheel focuses on the device on the colour wheel of along with being used for illuminating bundle, and calibrating installation has the focus as they focuses.

Advantageously, system comprises the projecting lens that is used for the projection imaging light beam and is used for the device and the rear projection screen of folding imaging beam.

According to another preferable feature; Said first surface comprises the surface that at least one is continuous; This continuous surface is designed to the said illuminating bundle break-in of part at least to said imager; Form the light beam of the break-in of the said imager of illumination thus, the light beam of this break-in is relevant with whole said first surface, and said first surface has the suitable global shape that matches with said imager.

Advantageously, said continuous surperficial or each said continuous surface all is no ridge.

According to the characteristic of a characteristic, said continuous surface is obeyed and is belonged to following group equation:

Polynomial equation;

Trigonometric equation;

Batten equation (spline); With

The combination of polynomial equation, trigonometric equation and/or batten equation.

According to specific characteristic, it is no ridge that said first surface has nonplanar facet and/or said first surface.

Advantageously, said first surface comprises:

At least the first district; It comprises the surface that at least one is continuous; This continuous surface is designed to the said illuminating bundle break-in of part at least to said imager; Form the light beam of the break-in of the said imager of illumination thus, the light beam of this break-in is relevant with whole said first surface, and said first surface has the suitable global shape that matches with said imager; With

At least the second district; It comprises facet; Each facet can both be with the said illuminating bundle break-in of part to said imager; Form the light beam of the break-in of the said imager of illumination thus, the light beam of said break-in is relevant with all facets, and all facets have the suitable global shape that matches with said imager.

Preferably, the area of said first surface is less than or equal to 16cm ²

According to a favourable characteristic, the aperture of illuminating bundle of leaving said optical element is between 3.2 and 5.

According to a preferable feature, said optical element is configured and disposed in the following manner, promptly reproduces the illuminating light flux of at least 95% the said optical element of illumination through said first surface.

According to a specific characteristic, system comprises colour wheel and the said colour wheel that is used for said illuminating bundle is focused on said focal region, and said calibrating installation has the point that is positioned at said focal region, as their focus.

According to a favorable characteristics, system comprises device and the rear projection screen that is used to throw the projecting lens of said imaging beam and/or is used for folding said imaging beam.

The invention still further relates to a kind of optical element that is used for video projector's illuminator; It comprises first surface; It is characterized in that; Said first surface is designed to the illuminating bundle of break-in incident in the following manner, and promptly being had in given plane by the light beam of said first surface break-in almost is the global shape of rectangle.

According to a favorable characteristics; Said first surface comprises facet and/or continuous surface; Said facet and/or continuous surface are designed to the illuminating bundle of the said incident of break-in in the following manner, i.e. it almost is the global shape of rectangle that the light beam of said break-in has in given plane.

According to a specific characteristic, said first surface reflects.

According to favourable deformation program, system comprise with said this surface difference of first surface opposing second surface seldom be plane or comprise will be from the calibrating installation of the similar calibration of illuminating bundle in any or a zone with the form of independent point.

According to another characteristic, said first surface reflects.

Advantageously, first surface comprises the calibrating installation of the illuminating bundle that is used to calibrate said incident.

Description of drawings

Through description with reference to the accompanying drawings, will understand the present invention better, and other details and advantage will become obviously, wherein:

Fig. 1 shows known illuminator;

Fig. 2 is the very schematically calcspar according to the rear projector of one embodiment of the invention;

Fig. 3 has represented the illuminator of in the rear projector of Fig. 2, using;

Fig. 4 shows the illuminator according to distortion embodiment of the present invention;

Fig. 5 and 6 has represented the details of the illuminator of Fig. 3 and 4;

The angle that Fig. 7 and 8 has described the light beam on the imager of the system known per of Fig. 1 own distributes;

The angle that Fig. 9 and 10 shows the light beam on the imager of the system that accordings to Fig. 2 of the present invention distributes;

Figure 11 to 14 has described the illuminator and corresponding lens according to distortion embodiment of the present invention;

Figure 15 and 16 shows the lighting pattern on the imager of the illuminator of Figure 12;

Figure 17 has represented the angle of inciding the light beam on Figure 12 illuminator imager and has distributed;

Figure 18 to 25 shows the illuminator according to distortion embodiment of the present invention;

Figure 26 to 32 has represented the lens with continuous surface that use in the system in Figure 20 to 25.

Embodiment

General Principle of the present invention is through using optical module reflection or transmission; The incident illumination light beam break-in in the district of self-focusing in the future; On at least one surface on this optical module surface, comprise and being used for the device of partial illumination light beam break-in to imager; Said optical module is provided with respect to the focal region, and structure, i.e. its illumination imager or change the shape of final light beam so that light beam is adapted to imager in the following manner.

Thereby the surperficial shape of at least one of said optical module makes the illuminating bundle break-in, in order to the imager that roughly throws light on equably.

According to each embodiment, this or these surface comprises at least one continuous surface (it is according to the density or the xsect of the alteration of form light beam of imager) and/or smooth facet (it converts incident beam to a plurality of independently light beams (it forms final light beam)).

The incident illumination light beam that is generally circle or oval cross section when getting into optical module is converted into the light beam (in the situation of rectangle imager) of the rectangular cross section of illumination imager; The homogeneity of imager integral illumination is controllable, thereby the illumination on the screen of projected image itself roughly is uniform.

Several embodiments of the present invention also have uses extremely thin advantages of optical components, and this extremely thin optical element uses less material and occupies very little space.

Use projector of the present invention also to have following advantage, can with the oval lenses for compatibility that in lens isis, has elliptical openings, thereby can improve the contrast of projected image, and not have extra loss, have less pupil size simultaneously.

Fig. 2 is the very schematically calcspar according to the rear projector 2 of first embodiment of the present invention.

Projector 2 comprises:

Illuminator 20;

Illuminating bundle 26 that reception is produced by illuminator 20 and the object lens 21 that produce light beam 25;

Rear projection screen 24 by light beam 25 illuminations; With

Thereby light beam 25 is folding and make that the degree of depth P of projector 2 reduces two folding mirrors 22 and 23.

Object lens 21, catoptron 22 and 23 and screen 24 and their setting be very known to those skilled in the art, will be not described in detail.

Fig. 3 shows in detail the illuminator 20 with transmission-type imager, and it comprises:

Produce the projection lamp 30 of illuminating bundle 35;

The colour wheel 31 of crosscut illuminating bundle 35;

Lens 32 are used to calibrate illuminating bundle 35, thereby produce the light beam 38 (if be no more than 6 ° of plus or minus from optical axis deviation, just thinking here that then light beam is similar calibration) of similar calibration;

Refraction optical element 33 comprises facet on one surface, and it converts light beam 38 to a plurality of light beams 36;

The imager 34 of transmission-type (transmission-type LCD), it almost perpendicular to the axle of light beam 36, by almost illumination equably of light beam 36, and produces imaging beam 37.

Facet described here is the surface that is limited on one or more ridges.

Projection lamp 30 comprises ellipsoidal reflector and the light source that is positioned at first along of ellipsoidal reflector, locates at the focus point (or district of partial points form) corresponding to second along, and ellipsoidal reflector focuses on illuminating bundle 35 on the colour wheel 31.

What optical element 33 was separated with imager 34 centers is following a kind of parameter apart from d2, and this parameter is used for the performance (luminous flux, uniformity coefficient and/or aperture) that the size of calibration degree (depend on lamp 30 with arc sizes lens 32), imager 34 according to light beam 38, the orientation that is positioned at facet on aperture and the optical element 33 of object lens of imager 34 back are come optimization system.For example, be measured as 0 for striding across diagonal line " 55 imager 34, d ' 2 is chosen as and equals 80mm, and d ' 2 is preferably between 50mm and 110mm.

Two vertical axle O ' x and O ' y have been confirmed in the plane of imager 34, and O ' is that central point, each O ' x and the O ' y of imager 34 is perpendicular to a side of imager 34.Equally, the central point on surface that comprises the optical element 33 of facet is expressed as O (O and O ' are along the optical axis setting of optical system), thereby can confirm that an Ox is parallel to O ' x, and an axle Oy is parallel to O ' y.

According to the complicated more distortion embodiment of the present invention, can use LCOS system relevant or the DMD relevant with the TIR prism with PBS.

Fig. 4 shows in detail the illuminator 40 of being out of shape embodiment according to the present invention.

Use identical reference marker with illuminator 20 and 40 components identical (especially lamp 30, wheel 31, lens 32), will be not described in detail.

Illuminator 40 further comprises:

Light beam 38 is converted to the optical element 41 of a plurality of light beams 42;

The imager 43 of reflection-type (DMD); Tilt a little 24 ° angle of its axle with respect to light beam 36; By almost illumination equably of light beam 36; And producing imaging beam 45 (it does not have crosscut optical element 41 or lens 32) respectively and corresponding to undesirable light beam 44 of light beam 42, this light beam 42 is to be produced by imager 43 reflections no matter imager 43 is positioned at active position or is positioned under the situation of inoperative position.

With lens 32 separate with optical element 41 preferably short as much as possible apart from d ' 1.According to a distortion embodiment of the present invention, this is zero apart from d ' 1.

With optical element 41 separate with the center of imager 43 apart from d ' the 2nd, following a kind of parameter, this parameter can be used for calibration degree (depend on lamp 30 with arc sizes lens 32), imager 43 according to light beam 38 size, be positioned at performance (luminous flux, uniformity coefficient and/or the aperture) optimization of the orientation of facet on aperture and the optical element 41 of object lens of imager 43 back with system.For example, be measured as 0 for striding across diagonal line " 55 imager 43, d ' 2 is chosen as and equals 80mm, and d ' 2 is preferably between 50mm and 110m.

Two vertical axle O ' x and O ' y ' have been confirmed in the plane of imager 43, and O ' is that central point, each O ' x and the O ' y ' of imager 43 is perpendicular to a side of imager 43.Equally, the central point on surface that comprises the optical element 41 of facet is expressed as O (O and O ' are arranged on the optical axis of optical system), thereby can confirm that an Ox is parallel to O ' x, and axle Oy is perpendicular to optical axis and Ox.

According to the complicated more distortion embodiment of the present invention, can use LCOS system relevant or the DMD relevant with the TIR prism with PBS.

Optical element 33 (or 41) comprises that perpendicular to the flat surfaces of illuminating bundle 38 and apparent surface 39 surface 39 is preferably on illuminating bundle outgoing one side.A part has been shown among Fig. 6 should surface 39; This part surface 39 comprises the part of being made up of facet 330 to 33n; Each facet 330 to 33n all is designed to a part of illuminating bundle 38 towards imager 34 (or 43) break-in, thereby almost throws light on imager 34 (or 43) equably.Preferably, facet is foursquare.The quantity of facet is preferably greater than or equals 12 and be less than or equal to 64 (quantity of facet is many more, and homogeneity is good more, but opposite, and the local loss of facet contact is just big more).For example, compromise preferably is that optical element has 36 facets.Each facet is especially so design all, (rectangle in other words) that promptly all facets produce the imager shape together almost be focused on the imager, uniformly and the illuminating bundle of smaller aperture due.For its two surfaces, optical element 33 (or 41) can cast in single operation in the B270 glass.

The surface 39 that comprises facet is considered to useful surface, and optical element 33 is preferably with respect to focal region and lighting source setting, and is configured to reproduce at least 95% the illuminating light flux that is used for illumination optical device through surface 39.

Projection lamp 30 for example is short-arc lamp (Phoenix

lamp for example; Specified 150 watts, has 1.0mm electric arc).For the lamp of given pattern, the space distribution of in the plane of the imager light of can calculating to a nicety very much and angle distribute, but in this situation the facet of gauging surface 39.

With lens 32 separate with optical element 33 preferably short as much as possible apart from d1.According to distortion embodiment of the present invention, this is zero apart from d1.

What optical element 33 was separated with the center of imager 34 is following a kind of parameter apart from d2, and this parameter can be used for the performance (luminous flux, uniformity coefficient and/or aperture) that the size of calibration degree (depend on lamp 30 with arc sizes lens 32), imager 43 according to light beam 38, the orientation that is positioned at facet on aperture and the optical element 33 of object lens of imager 34 back are come optimization system.For example, be measured as 0 for striding across diagonal line " 55 imager 34, d2 is chosen as and equals 80mm, and d2 is preferably between 50mm and 110mm.

In the description of use perpendicular to the imager of the light beam of illumination its (imager 34), simple in order to calculate, suppose that the surface portion 39 that comprises facet has with respect to axle Ox and four symmetrical in pairs quadrants of Oy.Similarly, can on imager, define with respect to axle O ' x and symmetrical in pairs four quadrants 340 to 343 of O ' y.Thereby; As shown in Figure 5; In 39 4 quadrants in surface each all be preferably relevant with the quadrant of the imager 34 of facing it 340 to 343 (in other words; The volume that is limited plane xOz and yOz (or xO ' z and yO ' z) (direction Oz and O ' z represent the direction of optical axis) is identical), thus the whole aperture of restriction illuminating bundle and imaging beam.Each facet 330 to 33p in 39 first quadrant of surface all reflects a part of incident beam, and the district 3401 of first quadrant 340 of its guiding imager 34 is arrived 340p.

More particularly; Quadrant 340 is divided into the individual fragment 3401 to 340p of p (equaling product rm); For in the fragment 3401 to 340p each, the facet of first quadrant on surface 39 is through predetermined function, and preferably the fragment through bijective function and quadrant 340 is relevant (for example defines r row and m row in first quadrant of surface 39 and imager 34; Row (or row) with surface 39 is relevant with the row (or row) of imager successively then, and is perhaps selectively fully at random relevant).

Next, calculate the center leave facet and incidence point average angle corresponding to the light beam 36 at appropriate section center.Calculate the degree of tilt of the facet that on exit direction, is refracted into irradiating light beam 38 then according to the average angle that is calculated.

This can obtain p facet, and each all has uses the vector refraction normal that equation calculated:

$\stackrel{\→}{l^{\′}}=n\stackrel{\→}{l}+J\stackrel{\→}{s}$ (J representes to reflect function).

Wherein:

Incident and emergent ray correspond respectively to vector l and l ';

N is the refractive index of the material (for example glass or transparent plastic) of element 33;

S representes the normal of faceted surface;

The value of J equals

$J=\stackrel{\→}{l^{\′}}\stackrel{\→}{s}-n\stackrel{\→}{l}\stackrel{\→}{s}$

Wherein, $S=\left(\begin{array}{c}x\\ y\\ z\end{array}\right);$ And $l^{,}=\left(\begin{array}{c}{u}^{\′}\\ v^{\′}\\ w^{\′}\end{array}\right)$

Then, if we establish α=(u '-nu), b=(v '-nv), c=(w ,-nw)

Then we the normal to a surface s that sees just is expressed as:

$\stackrel{\→}{s}=\left(\begin{array}{c}\frac{a}{\sqrt{a^2+b^2+c^2}}\\ \frac{b}{\sqrt{a^2+b^2+c^2}}\\ \frac{c}{\sqrt{a^2+b^2+c^2}}\end{array}\right)$

Be directed to each facet and carry out this processing successively, thereby obtain all arrangements.

During all light in describing four quadrants, imager 34 equably almost can throw light on.The aperture number of 90% luminous flux of can calculate total luminous flux (as number percent), capturing as the illumination uniformity of highest luminance number percent and by pupil by total luminous flux of lamp emission.Each system is characterized in that; Three parameters

(luminous power of luminous flux on the imager 34), f ( light beam 36 and 37 aperture number) and the u (homogeneity of illumination on the imager 34; It is corresponding to the ratio between minimum illumination and the highest luminance); All can confirm desired value (merit value) to each system; For desirable minimum uniform property; It is provided by following formula:

represent v, what M need be big as far as possible is big.The value of v for example equals 20%.

Can use other desired values according to changing.Thereby; For the homogeneity that satisfies; Can use following index formula: for the shadow mouth that reduces luminous flux to, also can use following formula:

Usually, can use the index formula of following form:

Wherein p and r represent integer (for example 1,2 or 3) or mark (for example 1/2), can choose as weighting parameters, are respectively applied for and estimate homogeneity and luminous flux.

Usually; Target function is the function of u and f; According to parameters needed; Can be to , more or less weighting of U and f.

According to distortion embodiment of the present invention, target function is considered by in thin rear projector or project image onto inhomogeneity loss on the screen that variation produced of incident angle near the projector the screen.For example through on the cross direction of imager, optical element being cut into inch strips the parameter function, every all is assigned specific uniformity ratio then, thereby compensation is because the inhomogeneity variation that geometric configuration caused of onscreen system.

Usually, the present invention can obtain homogeneity function arbitrarily: for this reason, all requirements are to make target function consider ideal uniform property, above parameter υ (smallest ideal homogeneity) in the index formula depend on the point on the imager of being considered.

The present invention also allows the illumination of Any shape, especially trapezoidal, hexagonal, oval-shaped etc.

In addition, the present invention and off-axis illumination (off-axis illumination) (wherein imager is not along the optical axis setting of system) compatibility can make the luminous flux loss minimum, and keep desirable form.

According to the computerized method of calculating said facet; Can preferably confirm more (generally being 10000) possible illuminator according to following algorithm; And select best one:, confirm to pass the incidence point of average light on imager at facet center arbitrarily for each facet; Calculate the orientation s of each facet then and depict all light that pass this facet.Next, brightness is added and, and parameter function.Can be according to the decline figure of index with system level, take best one (relevant with the highest M value that is obtained in other words one); Higher indicatrix can be guaranteed good homogeneous property, higher luminous flux and suitable aperture number.

Optical element 33 or 41 facet are preferably square or rectangle.According to various distortion of the present invention, optical element 33 or 41 facet can be arbitrary forms, and it can be identical or different.As one preferred, facet is set up in parallel with the mode of avoiding undesirable outgoing beam.Specifically, according to various distortion of the present invention, facet is arranged side by side with hexagon or leg-of-mutton shape.

According to a distortion embodiment of the present invention, keep the quadrant of optical element 33, the quadrant of optical element 33 is not symmetrical.Calculate the facet in each quadrant then separately, so that the homogeneity optimization on the imager 34 (can spill on the next quadrant) with the light beam of a quadrant dependence.

According to the present invention, two adjacent facets needn't have common ridge.According to several embodiments of the present invention; Optical element comprises the adjacent facet of different orientation; Border between them is not orthogonal to the normal of each facet: in this situation, corresponding facet does not have common ridge (this facet for example is the facet 330 and 331 among Fig. 6).As a reference, corresponding facet is connected by a surface in this situation, and the size on said surface is as much as possible little, with the loss of restriction luminous flux.

When the light beam off plumb imager that uses with illumination its (imager 43), have four quadrants cutting apart by axle Ox and Oy for the surface portion of simplifying calculating, suppose the optical element 41 that comprises facet.Similarly, axle O ' x has confirmed four quadrants that separate with O ' y ' on imager 43.Thereby; All preferred quadrant dependence (volume identical (direction Oz and O ' z represent the direction of optical axis) that defines by face xOz and yOz (or xO ' z and y ' O ' z) in other words, thereby total aperture of limiting illuminating bundle and imaging beam of imager 43 with in the face of it of each of four quadrants on element 41 surface.The orientation of the facet in four quadrants does not show specific symmetry, and the facet in each quadrant of preferred calculating optical element 41 separately is with the homogeneity optimization with imager 43 places.

According to distortion embodiment of the present invention, use the imager of the LCOS type relevant or the imager of the imager replacement DMD type of relevant transmission LCD type with the TIR prism with PBS.According to distortion embodiment of the present invention, maximum for the aperture that makes imaging and illuminating bundle, between optical element that is cut into facet and imager, insert object lens.According to these distortion embodiments, the calculating of the facet of optical element will be considered extra reflection and/or refraction (for example when inserting object lens, for the central ray of facet, the orientation of calculating facet will be considered the extra birefringence of institute's insertion lens).

Figures 7 and 8 describe the per se known system 10 of Figure 1 on an imaging beam 11 and two angular directions?

70 and?

71 on the angular distribution (obtained by simulation).According to Fig. 7 (or 8), for the aperture of 2.65 (or 3.5), said distribution spatially not have restriction (perhaps being limited by the marking of the light beam on the imager 11 respectively).Notice and do not exist the center of illumination to have blackening 72 corresponding to light source.In this situation, do not use illuminator to improve its ability.

Fig. 7 has shown the loss of light.What taken place is, when leaving photoconduction 102, has ± 30 ° angle.Lens 103 to 106 can reduce this angle, can this angle be reduced to ± 12 °, keep magnification simultaneously.Still reduced flux illumination than (etendue) (emittance area of photoconduction multiply by radiative solid angle in other words).

For the DMD of size HD3S (diagonal line measure 0 " 55), this system requirements uses the object lens with aperture between 2.4 and 2.8, and this size is higher relatively, needs use to have the object lens of a plurality of field lenses (fieldlens).

Fig. 9 and 10 shows at the angle according to the light beam on two angular direction

70 and

71 on the imager 34 of the present invention and distributes (obtaining through simulation), and this distribution table is shown it by the marking space constraint of the light beam on the imager 34.In Fig. 9 (or 10); This distribution table is shown and on all directions, has 3.5 aperture (or on direction

, be 3.5, on direction

, be 4.5).Can see and not have blackening in the center.Thereby the flux illumination ratio of illumination is optimized.

For aperture in one direction is 4.5, is 3.5 optical element 33 on another direction, has improved contrast, has removed the oval iris diaphragm (elliptical iris) that allows higher diffraction orders.

Thereby the present invention is consistent with the aperture of the optical element 33 of scope between 3.5 and 4.5 (comprising).Therefore corresponding object lens 21 needn't comprise field lens, therefore squint than the object lens with the systems compliant of Fig. 1.

In addition,, on the direction of propagation, have minimal interruption, can exempt the optical element that is used for illuminating bundle is separated with imaging beam (for example field lens or TIR prism (when imager is the transmission LCD type) for optical element 33.

Figure 11 and 12 shows illuminator 1100 and 1200 respectively; Comprise optical element 1101 and 1201 respectively; Its surface with calibration incident beam with comprise the second surface of facet, this second surface respectively with element 33 noted earlier and 41 cut apart by facet surperficial similar.System 1100 and 1200 advantageously replaces the system 20 in the projector 2, and their volume is less and implement simple (assembly is less).

More particularly, system 1100 and 1200 comprises the element of the system of being similar to 20 and 40, is not described further (especially projection lamp 30 and colour wheel 31) here.

System 1100 (or 1200) comprises optical element 1101 (or 1201), and this optical element comprises first surface 142 and relative illuminated second surface 140, with reference to Figure 13 (front view) and 14 (side views).

First surface 142 comprises zone 130, and this zone 130 is around rectangular area 131 and comprise that the square facet 1310 that is set up in parallel arrives 131p.Second surface 140 calibration illuminating bundles 35, thus be created in the light beam of propagating away from first surface 131 in the optical element 1101 that almost is calibrated.Second surface 140 is (forms that for example have Conical Lenses) sphere or aspheric.

Each all is designed to the facet of first surface 131 a part of illuminating bundle 35 break-ins to towards imager 34, thus with the similar mode of mode of the facet that calculates front illumination component 33, imager 34 equably almost throws light on.

According to distortion embodiment of the present invention, the zone 131 that comprises facet has non-rectangular shape, for example is strict circle (the edge facet that was cut), perhaps much the same circle (for example on whole surf zone, having same facet).

According to distortion embodiment of the present invention, zone 131 has occupied whole first surface 142.

Should be noted that element 1101 sizes are less relatively, the thickness e of edge surface 142 less (element 1101 is thinner), preferable range 3 and 5mm between.

Except considering that distance that imager 43 separates with element 1201 (this distance preferably is chosen for the minor increment that imaging beam 45 is not intersected with optical element 1201) and imager 43 calculate the facet with respect to the inclination from the light beam 42 of element 1201, element 1201 is similar to element 1101.

Figure 15 and 16 shows the illumination of the incident beam 42 on the imager 43, on imager 43, does not have and have the restriction of the marking of light beam 42 respectively.Bright spot is represented highest luminance.

Thereby the illumination difference that can see imager 43 seldom is uniformly, and most of light beam imager 43 that all throws light on, thereby it is higher to show the efficient of illumination imager.

In addition, illuminator 1100 and 1200 quality are similar to the quality of illuminator 20 and 40.

The angle that Figure 17 shows incident beam 42 on the imager with aperture 4 43 distributes.

Illumination relevant with Figure 15 to 17 and angle distribute corresponding to the imager that uses the DMD type, and still the imager (especially transmission LCD and LCOS imager) for other types also is effective.Can find out that the present invention allows to use the aperture more medium and small than prior art (for example the aperture is 4, rather than 2.5, keeps identical luminous flux simultaneously).

Figure 18 has shown the projector 180 that uses the optical element 181 with facet, and each facet is all towards imager 34 reflecting incident light bundles, and optical element 181 is by light beam 38 illuminations of similar calibration.

More particularly, projector 180 comprises the source electrode similar elements with projector 20, especially projection lamp light source 30, colour wheel 31, lens 32 and imager 34, and they adopt identical reference marker, no longer describe.

Each facet of element 181 is the plane preferably, and the angle that becomes to be scheduled to the optical axis of incident beam 38, thus with the break-in of partial illumination light beam to imager 34.According to distortion embodiment of the present invention, facet is not the plane, but slight curvature, for the orientation of calculating them is approximately smooth surface with them.

For the deformation program that uses reflective-mode and calculating facet, it is (element 181) situation of refraction through especially, is appreciated that the optical element 33 with facet is situations of refraction.

Thereby; According to the computerized method that is used to calculate facet; Algorithm below preferred the use is confirmed a plurality of (generally being 10000) possible illuminator, and best one is chosen as: for each facet, confirm to pass the incidence point of average light on imager at facet center arbitrarily; The orientation s of computing element 181 each facet then, and depict all light that pass this facet.Next, illumination is added and, and parameter function a target function of listing above for example using.System arranges according to the descending order of desired value, adopts best one (relevant with the highest M value that is obtained in other words those); Higher desired value can be guaranteed homogeneity preferably, higher luminous flux and suitable aperture number.

The facet of optical element 181 is preferably foursquare or rectangle.According to each distortion embodiment of the present invention, they can be arbitrary form, identical or different.As preferred scheme, facet is arranged side by side, to avoid undesirable outgoing beam.Specifically, according to various distortion embodiments of the present invention, facet is arranged side by side with hexagon or triangle.

Imager 34 illustrated in fig. 18 is transmission LCD types.According to the distortion embodiment of the projector 180 of the optical element 181 with band facet relevant with lens 32, imager can be DMD or LCOS type.

Figure 19 has shown the projector 190 that uses the optical element 191 with facet, and each facet is all towards imager 43 reflecting incident light bundles 35, and optical element 191 is thrown light on from the light beam that is positioned at the focus on the colour wheel 31 35.

More particularly, projector 190 comprises the source electrode similar elements with projector 1200, especially projection lamp light source 30, colour wheel 31 and imager 34, and they adopt identical reference marker, no longer describe.

Each facet of element 191 is the plane preferably, and the angle that becomes to be scheduled to the optical axis of incident beam 35, thus with the break-in of partial illumination light beam to imager 43.

With with the facet of the similar mode computing element 191 of the facet of element 181, true below considering, i.e. specified point place on element 191 each facet, incident beam is from a bit (for all facets of element 191, incident angle is inequality).Facet (in other words in the following manner, promptly formed following a kind of light beam by all facet beam reflected, this BEAM SQUINT optical axis absolute value is less than 6 °) with the mode computing element 191 of similar calibration illuminating bundle.

Imager 43 illustrated in fig. 19 is reflection DMD types.According to the distortion embodiment that has the optical element 191 of facet and do not have the projector 190 of independent calibration lens, imager 43 is transmission-type LCD or LCOS type.

Preferably be out of shape embodiment according to the present invention; Optical element 33; 41,1101,1201; 181 and 191 surface portion ground with facet or all by one or more continuous, preferably do not have ridge surface and replace, calculate the shape of respective optical element to the mode of imager with partial illumination light beam break-in at least.Light beam by the optical element reorientation has following global shape; This global shape is fit to match with imager (for example DMD, LCOS or transmission-type LCD) and illuminating bundle is evenly distributed on the imager, and this light beam makes the illuminating light flux optimization.The effective surface zone of the optical element of illuminating bundle break-in is comprised wholly or in part that the fact on one or more continuous surfaces especially makes makes optical element and becomes and be easier to.Also can obtain the pupil illumination of fine structure, therefore be more prone to even reproduction.Figure 26 to 32 shows the optical module according to this advantageous version embodiment of the present invention, and Figure 20 to 25 shows and uses this this assembly and corresponding to the illuminator of the system 20 of rear projector shown in Fig. 22.

Except that in order almost to throw light on imager equably with the illuminating bundle break-in to the optical element of imager, Figure 20 (with Figure 21 to 25) has also shown the similar illuminator of illuminator with Figure 11 (and Figure 12,18,19,3 and 4).Therefore the mutual component of 4,12,18 and 19 descriptions is no longer described with reference to Fig. 3.

More particularly, Figure 20 shows the 1100 similar illuminators 201 with system, and it comprises the optical element 2001 of substituted component 1101.System 201 is simple (assembly is less) especially, and volume is not very big.

Optical element 2001 comprises the incidence surface and the exit surface of calibration incident illumination light beam; The shape of exit surface is such; It is its xsect of revising illuminating bundle; Thereby light beam has the similar xsect that is fit to match with imager (in the plane of imager, the xsect of light beam almost is a rectangle, and the light beam imager that almost throws light on equably).

Optical element 2001 is for example corresponding to the optical element 260 that illustrates with reference to Figure 26 (front view) and 30 (side views).In (on imager one side) on its exit surface, it comprise effective surperficial 262 with diameter be some peripheral surfaces 261 arbitrarily of dt.

Effective surface 262 is continuous no ridge surfaces (from this surperficial equation), thereby is easy to make (for example through casting).Its round diameter du for example equals 25mm.This diameter designs according to the size of imager, preferably less than 40mm, is more preferably less than 30mm.Thereby for the effective surface 262 of circle, the area on surface 262 is preferably less than 12.6cm ², be more preferably less than 7.1cm ²Diameter d t for example equals du+2 or 5mm.Usually, dt can not surpass du 5mm, can limit the size of optical element like this.

The shape of gauging surface 262, the imager thereby illuminating bundle almost throws light on equably limits the luminous flux loss simultaneously.Therefore it is not common shape (for example planar shaped, sphere or ellipse), but has specific shape on the contrary, and the xsect (generally being circular or oval) that this specifically revises illuminating bundle becomes the xsect of imager shape (generally being rectangle) with it.

Through the mode of example, for 0.56 " imager, the shape on surface 262 is described according to following polynomial expression:

Z(x，y)＝-4.239646304650×10 ^-2x ²-3.326380966712×10 ^-2y ²-

1.966671669322×10 ^-5x ⁴-6.198237634196×10 ^-5x ²y ²-

6.426453423140×10 ^-6y ⁴+2.266408826592×10 ^-7x ⁶-

2.855371168045×10 ^-7x ⁴y ²-1.055433102635×10 ^-7x ²y ⁴-

2.548116290879×10 ^-7y ⁶-1.548363766813×10 ^-9x ⁸-

1.043474004569×10 ^-9x ⁶y ²+7.842149369509×10 ^-9x ⁴y ⁴-

8.156691681376×10 ^-9x ²y ⁶+5.430240779746×10 ^-10y ⁸-

1.046483939550×10 ^-12x ¹⁰-6.225724849459×10 ^-13x ⁸y ²-

4.903772428275×10 ^-13x ⁶y ⁴-2.052417294871×10 ^-12x ⁴y ⁶-

1.305693189623×10 ^-12x ²y ⁸-8.508867125822×10 ^-13y ¹⁰

For surface this shape of 262, the distance between the center of imager and surface (on imager one side) is 80mm.In addition, make the field of illumination positively consistent with imager, surface 262 is in 15 ° of the direction towards the axle x rotations from axle y.

For 0.56 " imager and lamp with 1mm arc size, the optical element 2001 that so limits makes imager by 40.4% luminous flux illumination of light emitted, and homogeneity is 39.8, and the illuminating bundle that leaves optical element 2001 has 3.85 apertures.

Surface 262 (more generally; All surface according to optical element of the present invention or system; Especially the surface of confirming with reference to Figure 20 to 32) be repeated the calculating optimumization of cycle calculations machineization, confirm the surface according to each repeating step, and calculate corresponding target function.As stated; System performance is confirmed by three parameters:

(luminous power on the imager 34 or luminous flux), f (light beam 36 and 37 aperture number (or numerical aperture) and u (homogeneity of the illumination on the imager 34, it is corresponding to the ratio of minimum illumination and highest luminance).With with the described similar mode of optical element that is used to confirm to have facet before; For example target function is

; Wherein p and r represent integer (for example 1; 2 or 3) or mark (for example 1/2), they are selected as the weighting parameters that is respectively applied for weighting homogeneity and luminous flux.Usually; Target function is

; The function of u and f; More or less to

, u and f carry out weighting (possibly consider the minimum or maximum restriction to one or more parameters) according to this parameter or favourable parameter.Preferably through surface deformation is come simultaneously with these three value optimizations.At first, with the form of equation, for example first surface is confirmed in the combination of polynomial expression, trigonometric expression or batten equation or polynomial equation, trigonometric equation and batten equation.Next, calculate corresponding target function, then target function and first surface are preserved the surface as optimized target function.Begin the double counting operation then.According to the step that repeats; Parameter (for example coefficient, phase place or the pulse value in polynomial expression or the trigonometric equation) through changing surface equation is confirmed distortion and surface equation (this surface can be known as and work as front surface); Describe out corresponding to when 100000 light of front surface, calculate corresponding target function then and the comparing of the optimizer system on the surface confirmed with the front, confirm corresponding to optimal parameter function surface.If target function is higher, then works as front surface and just become the surface of optimal parameter function, and preserve its equation and target function.For example when having obtained minimum target function value (in other words for example when target function on predetermined threshold value or when equaling this predetermined threshold value or when it no longer increases after predetermined repeat number) and/or when carrying out the repeating step of minimum number, stop calculating.

According to the embodiment of a distortion, optical element 2001 is for example corresponding to reference to the optical element 270 when the front is seen shown in Figure 27.On its exit surface, element 270 comprises effective surface 272 and the peripheral surface 271 that is similar to surface 261.

Effective surface 272 comprises four continuous basic surface that are arranged side by side 2720 to 2723, and each all is no ridge.Surface 272 is that diameter is the circle of du, and its periphery is similar to the periphery on surface 262.

The shape of gauging surface 272, the imager thereby illuminating bundle almost throws light on equably limits the luminous flux loss simultaneously.Basic surface 2720 to 2723 similar relevant (producing each surface all similar illumination and its corresponding a part of imager equably of illuminating bundle) with the part imager; Perhaps on the other hand; Basic surface 2720 to the 2723 not any specific region with imager is relevant, is on the whole the illuminating light flux imager that throws light on equably.Basic surface 2720 to 2723 can be similar (can reduce in order to confirm their required calculated amount) or not similar.According to the present invention, effective surface comprises the basic surface of a plurality of continuous no ridges, and these surperficial quantity needn't equal four, but can be two, three, six, eight etc., more generally, can be any numerical value.As a preferred scheme, although not necessarily, tie point itself is continuous between two adjacent basic surface, does not have unexpected interruption.

Equally, the border between the basic surface needs not to be straight.Thereby with shown in the side view, according to a distortion embodiment, optical element 2001 is for example corresponding to optical element 320 like Figure 32.Optical element 320 comprises the incidence surface 3203 and the useless peripheral surface 3201 of optics of the function of calibrating illuminating bundle.On its exit surface, element 320 comprises effective surface (having the diameter d u that describes like the front), and this effective surface itself comprises two concentric and continuous basic surface 3204 and 3202.Center surface 3204 is recessed spheries; It produces the light beam of non-uniform illumination imager.Surface 3202 around it has following shape, and this shape can be revised the inhomogeneity defective of illumination imager.Surface 3202 can have or not have ridge.

According to the embodiment of a distortion, optical element 2001 for example corresponding to respectively with reference to the optical element 280 or 290 shown in Figure 28 and 29, wherein, Figure 28 and 29 is front views.

On its exit surface, element 280 (or 290) comprises effective surface (or 292) and is similar to the peripheral surface 271 (or 291) on surface 261.

The effective surface of element 280 is circular, has the diameter that equals du.It comprises the continuous zone 282 (having or do not have ridge) that the center has the zone 283 of facet and centers on it; Zone 283 preferably foursquare (are easy to realize foursquare zone, can make it have facet foursquare and that shape is identical) with facet.

The effective surface of element 290 is foursquare, and side is long to be du, preferably is shorter than or equals 4mm (therefore the area of square effective surface preferably is less than or equal to 16mm2).It comprises the central area 292 and the peripheral zone with facet 293 with continuous surface.282 and 283 (or 292 and 293), zone similar relevant (producing each surface all similar illumination and its corresponding a part of imager equably of illuminating bundle) with the part imager; Perhaps on the other hand; Any specific region with imager is not relevant for they, is on the whole the illuminating light flux imager that throws light on equably.Can calculate a zone simply, and the imager that throws light on unevenly.The additional zone of effective coverage has the shape of so confirming, promptly it can revise the inhomogeneity defective of illumination imager.Especially, if replenish the zone corresponding to zone with facet, then can be to calculate its surface with reference to the similar mode of the mode with facet shown in Figure 5 with calculating.

Certainly, according to the optical element that the present invention can obtain other distortion, it uses at least one zone with facet and at least one continuous zone.According to the present invention, those skilled in the art especially can expect more having the zone and/or the more zone corresponding to continuous non-planar surface of facet.Those skilled in the art also can expect needing not to be the zone boundary of square or circular (for example triangle, hexagon, rule or irregular).

Figure 21 shows the illuminator 201 of the system of being similar to 1200, and it comprises the element 2101 of substituted component 1201.System 201 is simple (assembly is few) especially, and volume is not very big.

According to the present invention, remove the shape of effective surface of illuminating bundle break-in of the imager 43 that will throw light on, optical element 2101 is similar to element 2001, and said imager 43 is with respect to throwing light on its inclined light shaft of illuminating bundle 2102.Specifically, optical element 2101 has following one-piece construction (type of incidence surface, peripheral surface and effective surface), its corresponding to optical element with reference to the general structure compatible of Figure 26 to 30 and 32 described elements.Therefore this structure is no longer described.

Figure 24 (or 25) shows the illuminator 240 (or 250) of the system of being similar to 20 (or 40); It comprises the optical element 2401 (or 2501) of substituted component 38 (or 42); It has smooth incidence surface with can be with the effective surface of light beam break-in in the following manner; The illumination difference that is imager seldom is uniformly, and is identical with the respective surfaces of element 2001 (or 2101).Effectively, lens 32 are carried out the function of calibration incident beam, and this function is carried out by the incidence surface of optical element 2001 or 2101.Therefore descriptive system 240 and 250 no longer.

Figure 22 and 23 shows the illuminator 220 and 230 that is similar to system 180 and 190 respectively, and they comprise the optical element 2201 and 2301 of difference substituted component 181 or 191 respectively.

Optical element 2201 and 2301 comprises the effective surface of reflection; Its shape makes the xsect of illuminating bundle be modified; Thereby light beam has xsect that the similar shape that is fit to imager matches (in the plane of imager; The xsect of light beam almost is a rectangle, the light beam imager that almost throws light on equably).The reflecting surface of optical element 2301 is also calibrated the illuminating bundle of incident.

Effective surface is continuous no ridge surface, thereby makes easily.For example, as stated, it is that diameter is the circle of du.

According to the embodiment of various distortion, the effective surface of reflection comprises one or more continuous no ridge surfaces (pixel spare 270).According to other distortion embodiments of the present invention, the effective surface of reflection further comprises one or more zones (pixel spare 280 and 290) with facet.Those skilled in the art can adopt Figure 20, and 21 and 25 deformation programs to the transmissive element shown in 32 mate system 240 and the effective surface of 250 reflection among this paper.Therefore these deformation programs of the present invention are no longer described.

Certainly, the present invention is not limited to above-mentioned embodiment.

Specifically; The present invention can compatiblely use any imager or relate to the system of several imagers; This system for example comprises the optical element that has facet and/or have one or more continuous surfaces, the shaped design of this continuous surface several imagers that become to throw light on equably.

The present invention is also compatible to use several lighting sources, the optical element that this lighting source illumination has facet and/or has one or more continuous surfaces, the shaped design of this continuous surface at least one imager that becomes to throw light on equably.

In addition, the present invention can be advantageously utilised in the projector of front projection or back projection type.

Use the present invention of refraction optical element also compatible with the transparent refraction optical element that forms by any material (for example glass, birefringent material (quartz, kalzit, sapphire etc.) or plastics).

The light source of illumination can also be a light source (arc lamp etc.) arbitrarily, and it is relevant with the optical element that also is any kind, and this can go up at effective surface (facet cut apart and/or continuous) and obtain the illuminating bundle almost calibrated.

Those skilled in the art can also take other optical element, especially field lens, catoptron, optical fiber etc. to system of the present invention.

The optical element that use has facet and/or has a continuous surface is not limited to use has facet and/or continuous surface on first surface; Second surface is neutral or has the unzoned lens function; Also comprise following optical element; Thereby wherein first surface comprises facet and/or the continuous surface that itself and imager shape is matched the illuminating bundle break-in, second surface be the Fresnel lens-type or itself have facet.

The invention is not restricted to scenarios; Promptly wherein optical element comprises on first surface the device of partial illumination light beam break-in to imager; Thereby throw light on imager and the shape of light beam and imager are matched, these devices are (they are relevant with continuous surface or uncorrelated) reflection or reflection facet type.But; Facet can not be continuous surface (along the stretching surface that length the is limited on two relative ridges) replacement on plane what for example form bar shaped; Each bar shaped all is independent of another and reflects or the refractive break-in; Imager is arrived in the break-in of partial illumination light beam, thereby with its illumination, all these bar shapeds make together the shape of light beam and imager match.

The also compatible optical element that on one surface, comprises facet and bar shaped that uses of the present invention.

In addition, according to the present invention, the facet of optical element needs not to be smooth, but slight curvature.

Claims (12)

1. optical system, it comprises:

-at least one lighting source (30), it is designed to produce the illuminating bundle (35) that focuses on the focal region;

-at least one rectangle imager, it can produce imaging beam when being thrown light on by said illuminating bundle, and said imager has four quadrants;

-calibrating installation is used to calibrate the said illuminating bundle from said focal region;

-at least one optical element, it comprises:

-the adjacent facet on plane on the first surface of said at least one optical element; Said first surface has four quadrants; Each quadrant in these four quadrants and the different quadrant dependences of imager; Each facet in the adjacent facet on plane can both arrive the said illuminating bundle break-in of part towards said imager; The light beam of break-in of said imager thus is formed for throwing light on; The light beam of said break-in is relevant with the facet on all planes, and all facets have the suitable whole rectangular shape that matches with said rectangle imager, and it is relevant with the particular segment of the relevant quadrant of imager that each facet of any quadrant of first surface all passes through bijective function.

2. system according to claim 1 is characterized in that said calibrating installation is calibrated said illuminating bundle in the following manner, and promptly said light beam is from the value of its optical axis deviation absolute value less than 6 °.

3. system according to claim 1 and 2 is characterized in that said first surface reflects said illuminating bundle.

4. system according to claim 3 is characterized in that, said optical element comprises and said first surface opposing second surface that said second surface part at least forms said calibrating installation.

5. system according to claim 4 is characterized in that, said second surface is sphere or aspheric.

6. system according to claim 1 and 2 is characterized in that said first surface reflects said illuminating bundle.

7. system according to claim 1 and 2 is characterized in that the area of said first surface is less than or equal to 16cm ²

8. system according to claim 1 and 2 is characterized in that, the aperture of illuminating bundle of leaving said optical element is between 3.2 and 5.

9. system according to claim 1 and 2 is characterized in that said optical element is configured and disposed in the following manner, promptly reproduces the illuminating light flux of at least 95% the said optical element of illumination through said first surface.

10. system according to claim 1 and 2; It is characterized in that; It comprises colour wheel (31) and is used for said illuminating bundle is focused on the device on the said colour wheel of said focal region that said calibrating installation has the point that is positioned at said focal region, as the focus of said calibrating installation.

11. system according to claim 1 and 2 is characterized in that, it comprises the projecting lens (21) that is used to throw said imaging beam.

12. system according to claim 11 is characterized in that, it comprises device (22,23) and the rear projection screen (24) that is used for folding said imaging beam.

Images