CN1996120A - Grating trim retarders - Google Patents

Abstract

A grating trim retarder fabricated from a form-birefringent multi-layer dielectric stack including at least one anti-reflection coating and supported on a transparent substrate is provided. The form-birefringent dielectric stack includes an axially-inhomogeneous element in the form of a -C-plate grating and a transversely-inhomogeneous element in the form of an A-plate grating. Each of the -C-plate and the A-plate gratings are fabricated with dimensions such as to form a zeroth order sub-wavelength grating structure. Fabricating the grating trim retarder with anti-reflection coatings and/or a segment where the -C-plate and A-plate grating overlap enables the in-plane and out-of-plane retardances to be tailored independently according to the desired application.

Description

Grating trim retarders

Technical field

[01] the application relates generally to light delay device, is specifically related to grating trim retarders (grating trim retarder) and/or comprises the little display projection system based on LCD of this grating trim retarders.

Background of invention

[02] LCD (LCD) is widely used in the projection display of large screen television and monitor.In these optical projection systems based on LCD, high-power light beam before inciding the LCD panel via polarizer.Polarization of incident light is controlled on LCD panel individual element ground and with its corresponding polarizer/analyzer that leads again, it makes the light with suitable polarization be directed to the projecting lens that projects image onto screen again then.

[03] a kind of successful especially optical projection system based on LCD is based on the LCoS micro display system of WGP, and it uses wire-grid polarizer (WGP) and liquid crystal over silicon (LCoS) panel.When comparing with other little display techniques such as transmissive type liquid crystal display (xLCD), Digital Light Processor (DLP) and direct-view LCD, this micro display system is proved can show high resolving power and hi-vision contrast, it generally use three or the more little display panel of polylith (as every a kind of former colour band of correspondence) to improve screen intensity.

[04], shown the LCoS micro display system based on WGP of traditional 3-panel with reference to figure 1.This micro display system comprises it for example being the light source 5 and the lamp rod 7 of high-voltage discharge tube.The cone-shaped beam homogenising that lamp rod 7 produces light source 5 is to guarantee the space even light distribution.As selection, lamp rod 7 is the polarization conversion light pipes (PCLP) that are used to produce linearly polarized light.The first lens 8a will be delivered to first folding mirror (folding mirror) 9 from the light of lamp rod 7, and this first folding mirror 9 guides to first dichroic filter 10 with light.This first dichroic filter 10 is isolated blue light from all the other light, and the guiding blue light is through the second lens 8b and the 3rd lens 8c and second folding mirror 17 and the 3rd folding mirror 16 to the one LCoS display panel 20a.All the other light that are transmitted through dichroic filter 10 are directed through the 4th lens 8d and the 5th lens 8e and the 4th folding mirror 11 to second dichroic filters 12.Second dichroic filter 12 is divided into green glow and ruddiness with all the other light, and the former is directed to the 2nd LCoS display panel 20b for it, and its latter is directed to the 3rd LCoS display panel 20c.

[05] before arriving each LCoS display panel 20a, 20b and 20c, incident light is at first respectively by WGP15, WGP 14 and WGP 13 and adjustment delay compensator 21a, 21b and 21c.Each WGP 15, WGP 14 are the polarizer/analyzers that is formed by many parallel microfilaments (microwires) with WGP 13, the light of these microfilaments transmission polarization states and the direction quadrature of parallel microfilament, and the polarization by reflection attitude light parallel with these direction (for example, if polarizer is designed to by horizon light or P polarized light, as shown in Figure 1, microfilament will be perpendicular to the plane of Fig. 1).Each LCoS panel 20a, 20b and 20c individual element ground change the corresponding WGP 15 of light reflected back, WGP 14 and the WGP 13 after the linear polarization polarization of incident light also will be modulated.Because the propagation principal direction that each among WGP 15, WGP 14 and the WGP 13 all is oriented at relative light approximately ± 45 ° locate, so except as polarizer/analyzer, among WGP 15, WGP 14 and the WGP 13 each is also all as optical splitter, be used for by along and the output light path of input path quadrature is handled or deflection from the light of each LCoS panel reflection, incident light is separated from emergent light.More specifically, each among WGP 15, WGP 14 and the WGP 13 all reflexes to X-cube 19 with the S polarized light polarized light of the pixel half-twist that is in " energising " state (for example by).X-cube 19 is assembled (just assembling) image from each channel in three color channels, and by projecting lens 18 final image is projected (not shown) on the giant-screen.As selection, each color channel further comprises Prepolarization device (not shown) and/or delustring analyzer (clean-up analyzer) (not shown), and for example this can comprise one or more WGP and/or dichroic sheet polarizers.

[06] adjusting delay compensator 21a, 21b and 21c (be called for short and adjust delayer) here is the compensating element, that is used for improving the contrast performance grade of micro display system, and the residual birefringence that this contrast performance grade also is in the LCoS panel of dark state (as " closing " state) limits.Especially, each adjusts delayer 21a, 21b and 21c introduces phase delay, and this phase delay has been eliminated the delay that inherent birefringence caused by corresponding LCoS panel.Unless stated otherwise, term used herein " delay " or " delaying " are meant and the relative linear delay amount of circle retardation.Linear delay is the product of the thickness of the refringence of two quadratures and optical element.Linear delay causes two phase differential between the orthogonal linear polarisation, and one of them polarization direction is calibrated the very axle that is parallel to the linear delay device, and another polarization direction is calibrated the ordinary axle that is parallel to the linear delay device.Circle delay on the other side causes the relative phase difference between right-circularly polarized light and the left circularly polarized light.

[07] wire delay can be used to postpone or the face external delays in the description face.Be represented as in the face of optical path difference and postpone, be meant the difference between the refractive index and the product of optical element physical thickness in the face of two quadratures.The face external delays is meant along the refractive index of optical element thickness direction (z direction) and the difference of an interior refractive index of face (or mean value of the interior refractive index of face) and the product of optical element physical thickness.Normal incidence light in cone-shaped beam only exists in the face and postpones, and comprises that having experienced simultaneously in the face from axial ray of oblique ray (oblique rays) (just non-perpendicular but along main S plane and P plane) and oblique ray (skewrays) (just non-perpendicular and away from S plane and the incident of P plane) postpones and the face external delays.Especially, in birefringent medium,, do not observe delay in the face for the small probability situation of 90 ° of ray angles.

[08] in the situation of not adjusting delayer 21a-c, because the residual birefringence of LCoS panel 20a-c, the polarized light of the P polarization of every little display panel of irradiation is in reflex time quilt elliptic polarizationization a little under dark state (" closing " state).When the elliptically polarized light that comprises P component and S component is transferred to corresponding WGP 15, WGP 14, WGP 13, the S component is reflected back toward the X-cube, allows dark state light to leak on the giant-screen like this, and then has limited the contrast of optical projection system.

[09] postpone in the face of the delay that is produced by the residual birefringence of LCoS panel 20a-c by affording redress, the use of adjusting delayer 21a-c has improved contrast level.More specifically, adjust delayer 21a-c and be directed the slow axis that makes them and be set on the orientation with slow axis (being called " the intersecting axle ") perpendicular array of LCoS panel 20a-c, and the fast axle of adjusting delayer 21a-c is set on the orientation of arranging with the fast axle orthogonal azimuths of LCoS panel 20a-c.Term slow axis used herein (SA) and fast axle (FA) are meant when two Orthogonal Double refraction axis when the normal incidence slotted line postpones.Especially, for the negative external delays component of wide-angle incident, SA and FA orientation are along with changing from the axle irradiation and changing the effect of the SA/FA that also can reverse.

[10] because adjusting the slow axis of delayer 21a-c and LCoS panel 20a-c is set on the orthogonal orientation angular range, from adjusting delayer 21a-c to LCoS panel 20a-c, the effect of fast/slow axis is exchanged for normal incident light.In other words, the light with special polarization state is alternately postponed more lessly then adjusting delayer 21a-c and LCoS panel 20a-c respectively, and perhaps vice versa.Actual effect is that incident light polarization is had the zero relative delay, does not therefore change polarization state (that is to say that output light is not by elliptic polarization).Corresponding WGP 15, WGP 14, WGP 13 and/or optional depolarizer (clean-up polarizer) have stopped output light then, can not appear on the screen to such an extent as to dark status panel light leaks.Because adjust the output that delayer 21a-c does not have obviously to change the panel "on" position, the contrast of gained (standard-sized sheet/complete shut-down) is good subsequently.

[11], further show the principle of work that each adjusts delayer 21a-c among Fig. 2 with reference to the magnetic core optical device (core optics) of single channel photo engine (light engine).These magnetic core optical device comprise Prepolarization device 30, WGP31, adjustment delayer 32, homeotropic alignment to row (VAN) type LCoS panel 33 and depolarizer (not shown).In operation, the light of the unpolarized or partial polarization that is sent by prime illumination (not shown) passes Prepolarization device 30 to obtain the P polarized light.This light passes WGP 31, and its polarization extinction ratio is enhanced.Adjust delayer 32 preconditioning incident P light beams and produce oval output.Ideally, the ellipticity that is incident on the polarized light of (this panel is in secretly and (closes) in the state) on the LCoS panel 33 can not be realized by the panel delay of remnants.Reflected light is finished by VAN-LCoS panel 33 and after adjusting the binary channels of delayer 32, is therefore still being kept the P polarization.Remaining P polarized component by WGP 31 transmission is projected back illuminator, and finally is depleted.

[12] as indicated above, adjusting delayer 32 provides under off status the A-panel that postpones coupling in the face with corresponding LCoS panel 33 to postpone ideally.Because the manufacturing tolerance in device thickness, material birefringence control and the operation drift (temperature, mechanical stress etc.), LCoS panel 33 postpones all to be tending towards changing in each component with the A-panel of adjusting delayer 32 yet in fact.Therefore in order to ensure sufficient compensation, on adjustment delayer 32, provide usually to have the higher A-panel delay of delay that shows than LCoS panel 33.For example, having adjustment delayer that 10nm A-panel postpones (at 550nm wavelength place) is used to compensation usually and shows that 2nm A-panel postpones the VAN type LCoS at (at 550nm wavelength place).

[13] known to those of skill in the art as those, with respect to above-mentioned nominal intersecting axle configuration, this mispairing of A-panel numerical value need be adjusted the skew of the optical axis of delayer 32.In other words, adjusting delayer makes it be mated (clocked-in) away from the intersecting axle configuration by rotating its azimuth direction.For example, referring to J.Chen, M.G.Robinson and G.D.Sharp, " General Methodology for LCoS Panel Compensation (conventional method that is used for the compensation of LCoS panel); " SID 04, Digest, pp.990-993,2004. Fig. 3, the document shows the relative orientations arc angular direction of LCoS panel and adjusts the delayer slow axis, illustrate in adjacent quadrant, how the adjustment delayer of higher value passes through angle φ quilt " (clocked) synchronously " away from S plane of polarization and P plane of polarization.As mentioned above, when the slow axis of VAN-LCoS panel is divided S and P plane of polarization equally with fast axle, when LCoS postpones very little (for example＜＜λ/50), postpone to reach quarter-wave for adjusting delayer A-panel, overclocking angle (over-clocking angle) φ is provided by following formula:

$\mathrm{\φ}\≈\frac{{\cos }^{-1}\left(\right[{\mathrm{\Γ}}_a\left(\mathrm{LC}\right)/{\mathrm{\Γ}}_a\left(\mathrm{TR}\right)\left]\right)}{2}$

Wherein, Г _a(TR) be that the A-panel of adjusting delayer postpones Г _a(LC) be the A-panel delay of LCoS.Therefore, postpone in LCoS shows the 2mm face, the adjustment delayer provides when the face of about 10nm is interior to postpone, and the overclocking angle is about 39 °.

[14] postpone except providing in the face, adjusting delayer 32 also can provide the face external delays to increase the visual field usually.More specifically, adjust delayer and generally include the C-panel compensating unit that is used for the A-panel compensating unit that postpones in the complementary area and is used for the displaying negative birefringence of complementary area external delays.As selection, these global functions A/-C-panel is adjusted delayer and is also comprised the O-panel component.The A-panel be its very axle be parallel to the birefringent optical element of panel place planar orientation.The C-panel is its very birefringent optical element perpendicular to panel place planar orientation (that is to say, be parallel to the normal incidence direction of light).The O-panel is its very birefringent optical element of axle (being its optical axis or c axle) and plane, panel place bevel orientation.

[15] some examples that are used to form the material of A-panel component comprise the uniaxial tension polymer film such as polyvinyl alcohol (PVA) (PVA) film or polycarbonate (PC) film, the uniaxial orientation film of liquid crystal polymer (LCP) material is such as two organic thin slices of non-inclination of acetate fiber, birefringece crystal and inorganic thin film.Some materials that are used to form the C-panel component comprise discoid liquid crystal (discotic) film and with the liquid crystal polymer (LCP) of linear photopolymerization (LPP) technology orientation.For the latter, cholesteric LCP layer must have short pitch (that is, shorter than the minimal wave length in operating wavelength range) and the reflection at peak in the UV ultraviolet light range.The adjustment delayer based on LCP/LPP that is produced has been proved in reliability, homogeneity and has been easy to reach the party in delay mask very many purposes, and in addition, this adjustment delayer also is proved contrast compensation and the environmental stability that provides good.

[16] also increasing to the concern of adjusting delayer, birefringence produces (that is form birefringent) rather than above-mentioned molecular briefringence by the layout of diffraction element in this adjustment delayer.

[17] the known holographic element that is constructed to approach (promptly not being volume edogram) and to have much larger than the diffraction grating of the characteristic dimension of the optical wavelength that is used to produce diffraction output be polarization sensitive basically.According to the scalar diffraction theory that the hypothesis paraxial ray is propagated, the diffraction output at each m level place is calculated by following formula:

$\sin \left({\mathrm{\θ}}_m\right)=\frac{\mathrm{m\λ}}{\mathrm{\Λ}},$ And

$I_m={\left(\frac{2}{\mathrm{m\π}}\right)}^2,$

Wherein λ is an optical wavelength; M is the odd level of diffraction; θ is angle of diffraction (supposing normal incidence in air turnover medium); Λ is a raster pitch.

[18] this intensity expression formula comprises implicit hypothesis horizontal, pure phase position binary raster.In other words, suppose that this grating has the modulation pattern that is substantially perpendicular to the device normal, and the essentially no loss of this grating, and this modulation is subjected to the influence of phase encoding rather than intensity coding.Also suppose grating be rule and do not have pixelation and no shadow zone (dead-space) effect.For the situation with pixelation/no shadow zone (that is, non-50% dutycycle square-wave grating) and general hologram pattern, the expression formula that can obtain more heterogeneous pass is with the output of prediction at each angle of diffraction place.For example, referring to K.L.Tan et al., " Dynamic holography for optical interconnections.II.Routingholograms with predictable location and intensity of each diffraction order ", J.Opt.Soc.Am.A, 18 (1), pp.205-215,2001.

[19] still, if the transverse diffraction grating has the characteristic dimension of the part of the optical wavelength that just is used to produce diffraction output, have only Zero-order diffractive will be reflected/transmission so.All other level fade away (being that non-zero order begins decay outside distance grating planar certain distance).Grating is that polarization is relevant at present.For one-dimensional grating, be parallel and perpendicular to the P face (also being the TM ripple) and the S face (also being the TE ripple) of grating vector respectively, complex amplitude transmission/reflection has different characteristics.In addition, at the normal incidence place, very important with the difference of the effective refractive index that is orthogonal to grating vector along grating vector.Grating is the birefringence element with effective extraordinary refractive index and ordinary refractive index at present.Zero level sub-wave length grating (ZOG) is the form birefringent element, and wherein the index modulation of grating (and so phase modulation (PM)) is (promptly along the grating vector direction) laterally heterogeneous.Vector diffraction computational tool (perhaps model analysis or accurate coupled waves analysis) needs prediction this transmission/reflection complex amplitude amount.

[20] for many years, for example the grid structural detail of metal gate polarizer is obtainable for IR wavelength and microwave frequency.The demand of making these elements with the sub-wavelength characteristic dimension is to satisfy easily, because the wavelength of these application need electromagnetism (EM) radiation is in micron arrives submillimeter scope.Recently, make in the progress of semiconducter IC (integrated circuit) technical elements and can obtain such photoetching technique: making can be manufactured less than the transistor gate size of about 90nm, and about 100nm characteristic dimension of visible band application required (promptly in about 400nm to 700nm scope) therefore can be provided.

[21], simple, one dimension binary grid structure are shown with reference to figure 4.Laterally grid structure 100 comprises three main elements: second group of parallel lines 120 of first group of parallel lines 110 of first material, second material that intersects with first group of line, the substrate 130 of the substantial transparent of these two groups of lines is installed on it.The wire-grid polarizer that this basic surface relief structure can be sold with commerce (for example, by Moxtek) form obtain, wherein first group of line formed by evaporation aluminium (and/or other dielectric material), and second group of line is simple air-gap (for example, when space that the Al layer produces during by partial etching).Other optical film (optical stack) such as the antireflection on the second surface that is coated in substrate usually (AR) layer is not shown.The current potential etch stop layer and the overlayer of optical grating construction are also not shown.

[22] although binary (rectangle) grating pattern is described, laterally non-uniform Distribution (along the x direction) also can be zigzag (triangle), glitter, sinusoidal, trapezoidal etc.All comprise two or more light paths each modulation period along the device normal direction.This point can be by producing two or more different materials or accomplished by the combination of material and physical layer thickness variation at same height (being same physical thickness).Although should be noted in the discussion above that these two material/zones provide different bit phase delays in theory, in fact, owing to light can't be offered an explanation the sub-wavelength pitch and produced this average effect.Illustrate on the conical erecting frame of this grating device in the dextrorotation XYZ coordinate system, and have along the incidence electromagnetic radiation of wave vector 140 directions in plane 141.The plane of incidence 141 constitutes position angle 146 with the plane (being the XZ plane) that comprises grating vector.Incident vector 140 tilts at incident polar angle (AOI) 147 places with respect to device normal direction 145.In display application, position angle 146 changes in 0-360 ° of scope, and polar angle 147 is provided by semi-cone angle.In general the application, the cone axis of incident EM ripple can with or not consistent with the device normal.

[23] for the wire grating polarizer, this grid device transmission substantial linear and be parallel to grating vector first polarization of (promptly being parallel to X-axis), and second polarization reflection substantial linear and that be parallel to line direction (promptly be parallel to Y-axis or perpendicular to grating vector).For gate device, effectively MEDIUM THEORY (EMT) is applied to producing approximate effective ordinary refractive index n _o, and effective extraordinary refractive index n _eZero level effective refractive index n _o ⁰And n _e ⁰Provide by following formula:

$n_o^0=\sqrt{f{\left(n_1\right)}^2+(1-f){\left(n_2\right)}^2}$ And $n_e^0=1/\sqrt{f/{\left(n_1\right)}^2+(1-f)/{\left(n_2\right)}^2}$

N wherein ₁And n ₂It is respectively the refractive index of first material and second material; F is the dutycycle of the width of first material to the grating cycle.Top EMT formula can be applicable to the quasistatic limit of grating cycle near 0 width.In actual applications, one group of second level EMT expression formula is to effective refractive index n _oAnd n _eProvide better approximate:

$n_o^0=\sqrt{{\left(n_o^0\right)}^2+{\left(\frac{p}{\mathrm{\λ}}\right)}^2\frac{{\mathrm{\π}}^2}{3}{f}^2{(1-f)}^2[{\left(n_1\right)}^2-{\left(n_2\right)}^2{]}^2}$ And

${\mathrm{<figure-callout\; id="0"\; label="n\; e"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}_e^{}=\sqrt{{\left(n_e^0\right)}^2+{\left(\frac{p}{\mathrm{\&lambda;}}\right)}^2\frac{{\mathrm{\&pi;}}^2}{3}{f}^2{(1-f)}^2[1/{\left(n_1\right)}^2-1/{\left(n_2\right)}^2{]}^2{\left(n_o^0\right)}^2{\left(n_e^0\right)}^6}---\left(2\right)$

Wherein, zero utmost point effective refractive index n _e ⁰And n _o ⁰Be used for information, further limit the approximate effective refractive index n in the second level according to operation wavelength λ, raster pitch p and dutycycle f _e ⁰And n _o ⁰

[24] according to the EMT theory, horizontal non-homogeneous grating is effective birefringent medium, and it comprises and has effective refractive index n _e, be parallel to the e ripple axle of grating vector (X-axis) orientation.This point is shown by equivalent devices 150 in Fig. 5.Has ordinary refractive index n _o O ripple axle 152 perpendicular to having extraordinary refractive index n _e E ripple axle 153, and be positioned at the YZ plane.This EMT layer has n _e＜n _oNegative birefringence.If Lamellar grating comprises dielectric grid rather than metal gate, two be substantially zero so to attenuation characteristic, lag characteristic is essentially single (unity).In this case, produce A-panel delayer with delay in the face.For this grating, postpone to be (n _o-n _e) h, wherein h is a grating bed thickness 151.This delayer is called as A-panel delayer, and meaning it is the A-panel delayer with negative birefringence.Its importance is to postpone to distribute the AOI along the e corrugated is shown increase with the AOI appropriateness rather than the faint reduction under the situation that positive A-panel component exists.

[25] at US patent No.6, in 532,111, people such as Kurtz propose the line of dielectric grid polarizer that formed by horizontal non-homogeneous non-conductive wire grid construction, and wherein the etching base is to form by the multilayer dielectric film.Although this wire grid devices is applicable to visible waveband and uses that the polarization of wiregrating (two to decay diattenutation) characteristic is very high, therefore, this device reflecting properties is too strong and can not be with adjusting delayer.

[26] being used for the dielectric grid optical delay that achromatism, high-magnitude postpone to use is proposed (promptly by people such as Bokor, N.Bokor et al., " Achromatic phase retarder by slanted illumination of a dielectricgrating with period comparable with the wavelength ", Appl.Opt.40, (13) pp.2076-2080,2001).But,, use it for parallel beam and mean that it is inappropriate using for the little display image based on LCD of routine because the device that is proposed needs high angle circular cone mount pad.In addition ,-lacking of C-panel feature make this equipment especially be unsuitable for the projection contrast compensation.

[27] in US patent No.20050045799, people such as Deng propose can to debate photoetching method by oversubscription by the achromatic basically light delay device that dielectric grid forms and make.The device 200 that is proposed in Fig. 6 comprises the horizontal non-homogeneous grating 210 that is installed in etch stop layer 230 tops and is covered by overlayer 240.This grating comprises at least two face shapes (profile) 211 and 216, and each face shape can be a multilayer.Usually structure 216 is set to the spacing between " wall " 211.These walls are by the remaining pedestal of etching technics.By oblique evaporation plating cap rock, therefore can not insert basically in the space between the wall.Grating 210 with and process required layer 230 and 240 and be installed on the transparency carrier 220, it is 250 and 260 that the outside surface of the device that is produced is coated with multilayer AR film.The enlarged drawing of optical grating construction 210 is described in Fig. 7.Grating 210 has layer thickness h, and the width of wall 211 and spacing 216 is respectively w ₁And w ₂Dutycycle f is provided by following formula:

f＝w ₁/(w ₁+w ₂) (3)

And EMT expression formula (1) and (2) can be used for approximate effective ordinary refractive index and extraordinary refractive index.The difference of these refractive indexes provides effective birefringence, and this effective birefringence is a negative value.Although the light delay devices that the people proposed such as Deng have been used for comprising the multiple optical application of polarizer, isolator, AR design, but it is unsuitable for using based on the little display image of LCD usually, projection application particularly, because its shortage-C-panel component and the reflection of high cross polarization, the latter should be owing to birefringent use in the efficient face.

[28] at US patent No.5, in 196,953, people such as Yeh propose the form birefringent light delay device, and wherein this form birefringent is produced by axial heterogeneous texture rather than above-mentioned horizontal heterogeneous texture.Axially heterogeneous texture comprises first series of strata with first refractive index, and these first series of strata replace with second series of strata with second refractive index.Select first and second refractive index value and the bed thickness in first and second are so that this structure provides-the C-panel feature.More specifically, produce following formula:

|Δn _L|d _L＝|Δn _C|d _C

Wherein Δ n is birefringence, and d is a bed thickness, and subscript " L " and " C " refer to switchable LC layer and dielectric form birefringent compensator in display panel respectively.In a preferred embodiment, the low-refraction value n in the LC layer _oWith high index of refraction value n _ePartly be complementary with compensator.Unfortunately, this method has greatly limited dielectric form birefringent compensator type of material as used herein, and need be to the accurate measurement of material constant and coating thickness.In addition, for big C value, with n _oAnd n _eBe restricted to the n of LC layer _oAnd n _eNeed very thick coating.

[29] in US patent No.20050128391A1, people such as Tan have disclosed a kind of adjustment delayer, and wherein form birefringent is also produced by axial heterogeneous texture.More specifically, people such as Tan instruction form birefringent (FB) is provided axial non-homogeneous birefringent structure easily and one or more layers antireflection (AR) coating is combined has to provide-the FBAR element of C-panel feature.Advantageously, because FB shows negative (C-panel) face external delays, the AR coating is general shows that positive (+C-panel) face external delays, total reflection and clean C postpone all by tuning to satisfy compensation LCoS panel and/or the necessary condition of employed other polarization sensitive device in optical projection system expediently.

[30] with reference to figure 8, FBAR adjust delayer 300 comprise A-panel component 310 and-C-panel component 350, the both is installed on the transparency carrier 390.The A-panel component generally comprises the molecular briefringence layer 320 that has the refractive index match layer and/or process required layer 321 and 322.-C-panel component comprises the alternately refractive index assembly of thin films 360 of the form birefringent of showing axial orientation.Similarly ,-C-panel component 350 can comprise refractive index match layer 361 and 362.The whole film that comprises refractive index match layer 361 and 362 is 350 to help total-C-panel feature and adjust the AR performance of delayer 300.

[31] with reference to figure 9, axially heterogeneous texture 360 comprises the alternately assembly of thin films of refractive index, and this assembly of thin films has first multilayer 370 and second multilayer 380, and wherein every layer of first multilayer 370 all has first refractive index n ₁With first thickness d ₁, every layer of second multilayer 380 all has second refractive index n ₂With second thickness d ₂, second multilayer 380 and first multilayer 370 alternate.Dutycycle is provided by following formula:

f＝d ₁/(d ₁+d ₂) (4)

EMT formula, formula (1) and (2) can be used for the approximate Double refracting characteristic, although be enough to handle axial isotropy thin layer heterogeneous based on the film counter of matrix, and are not horizontal homogeneous isotropism thin layer.

[32]-C-panel-form birefringence AR can be conceptualized as negative mono-axial refractive index curve, such as the equivalent devices among Figure 10 350 description.Refractive index curve is in the form of annular discs, and e ripple axle 353 is parallel to z axle orientation, and o ripple axle 352 quilts are perpendicular to e ripple axle orientation and be arranged in the multilayer film plane.

[33] be increased to several thousand to one (for example from hundreds of than one with picture contrast although shown the global function A/-C-panel delayer that comprises low reflective design with the LCoS display system of VAN pattern, referring to K.Tan et al., " Designand characterization of a compensator for high contrast LCoS projection systems ", SID 2005, p.1810,2005), still be desirable to provide the adjustment delayer of improvement.

Summary of the invention

[34] the present invention relates to comprise the light delay device of horizontal and axial heterogeneous texture.Particularly, the present invention relates to comprise A-panel grating and-the adjustment delayer of C-panel grating, A-panel grating has along the periodic regions of the transverse plane of device ,-C-panel grating has along the periodic regions of device normal.The thickness of the width of the periodicity wall in A-panel grating and the periodicity layer in-C-panel grating is chosen as the mark of operation wavelength so that the form birefringent effect to be provided.These zero level gratings are coupled so that low reflection, global function adjustment delayer to be provided with one or more layers AR coating easily, and this adjustment delayer helps improving the picture contrast based on little display image browser of polarization.

[35] the invention further relates to the projection display system based on polarization (for example, having reflective liquid crystal over silicon (LCoS) or transmissive liquid crystal display (xLCD) panel) that comprises global function adjustment delayer (that is, having horizontal and axial heterogeneous texture).In these optical projection systems, global function adjustment delayer is generally comprised as resolution element or is integrated with another optical element.For example, for the latter, global function adjustment delayer is integrated into a substrate easily or clamps in two substrates of liquid crystal display.

[36] advantageously, the birefringence that this global function is adjusted delayer mainly by the A-panel and-C-panel grating produces, these two gratings all are Zero-order diffractive structure (that is, horizontal raster do not produce horizontal space filtering, and axially grating does not produce longitudinal mode filtering (wavelength)).In other words, the birefringence of this global function adjustment delayer is mainly produced by the structure (form) of basic optical element.Therefore, adjust delayer and make by multiple material (for example full-inorganic dielectric) easily, and generally can not lose its birefringence owing to time and/or high flux exposure.In addition, because birefringence is mainly produced by structure, device specification adapts to different application/environment easily by changing structure, for example, the A-panel and-C-panel grating can independently be revised and/or overlapping so that the expection device specification to be provided.

[37] obvious, the present invention is desirable to provide a kind of for any wavelength in required AR scope, be illustrated in the A-panel that changes between the 1nm-400nm postpone and between 0nm to 1000nm, change-light delay device that the C-panel postpones.Particularly, the invention provides a kind of for any wavelength in required AR scope, be illustrated in that the A-panel that changes between the 1nm-250nm postpones and 0nm to change between-the 1000nm-global function that the C-panel postpones adjusts delayer.For the A-panel and-partially overlap at least embodiment of (coincide) of C-panel grating, the A-panel postpones generally littler.

[38] according to an aspect of the present invention, a kind of light delay device is provided, this light delay device comprises: comprise first multilayer with first refractive index and first thickness and have second refractive index and the axial non-homogeneous element of second multilayer of second thickness, this first multilayer and this second multilayer alternately select this first thickness and second thickness and this first refractive index and this second refractive index that the zero level sub-wavelength grate structure of negative face external delays is provided with formation; Comprise more than first zones with first refractive index and first width and horizontal non-homogeneous element with more than second zones of second refractive index and second width, more than second zones in these more than first zones and this alternately select this first width and this second width and this first refractive index and this second refractive index to provide the zero level that postpones in face sub-wavelength grate structure with formation; And at least one substrate that is used to support this axial non-homogeneous element and horizontal non-homogeneous element.

[39] according to another aspect of the present invention, provide a kind of light delay device that adopts to strengthen based on the system contrast method in the optical projection system of liquid crystal display, this method comprises: the location is as the light delay device that arbitrary claim limited among the claim 1-10, so that the residual retardance of the display panels in this optical projection system is compensated basically in optical projection system.

[40] according to another aspect of the present invention, provide a kind of optical projection system based on LCD, this optical projection system comprises: light source; First polarizer, the light that is used to receive from this light source also transmits first linearly polarized light with first linear polarization axle; Display panels is used for this first linearly polarized light of optical modulation, and this display panels has residual birefringence; Second polarizer is used to receive the light after the optical modulation, and is used to transmit second linearly polarized light with second linear polarization axle; Projecting lens is used for this second linearly polarized light is incident upon display screen; And light delay device, being used to compensate the residual birefringence of this display panels, arbitrary claim limits among this light delay device such as the claim 1-10.

[41] according to another aspect of the present invention, provide a kind of manufacture method of light delay device, this method comprises: deposition replaces refractive index multi-layer thin membrane system on substrate, and alternately refractive index multi-layer thin membrane system provides-C-panel optical grating construction; And the thickness section etching that will replace refractive index multi-layer thin membrane system for the transverse area that replaces so that A-panel optical grating construction to be provided.

[42],, should use these definition unless in claims or in the other parts of instructions, provide different definition for the term that defines below.

[43] term " coherent optics layer " is understood to include the thin layer with the thickness that is equal to or less than the illumination wavelengths grade.

[44] term " noncoherence optics layer " is understood to include for having much larger than the substrate of the film of the thickness of illumination wavelengths.

[45] term " relevant coupling " is understood to include a plurality of sections of cascade of the film system that does not adopt the noncoherence optics layer.

[46] term " incoherent coupling " is understood to include a plurality of sections of cascade of the film system that is separated by the noncoherence optics layer.

[47] term " conforming layer " is understood to include the coherent optics layer, and refractive index is uniform on the degree of depth of layer and lateral dimension basically in this optical layers.

[48] term " heterosphere " is understood to include the coherent optics layer, and refractive index is uneven on the degree of depth of layer and/or lateral dimension basically in this optical layers.

[49] term " evenly delayer " is understood to include the light delay element, in the face that in this light delay element, postpones and the degree of depth of the outer component leap of face element evenly distribute.

[50] term " non-homogeneous delayer " is understood to include the light delay element, in the face that in this light delay element, postpones with face outside component be distributed on the different sections of secondary element the incoherent or relevant coupling of all these different Duan Douke.

[51] term " EMT " is interpreted as being meant effective MEDIUM THEORY, and wherein periodic isotropic refractive index structure is described to have the negative single axial birefringence layer of effective ordinary refractive index and effective unusual refractive index.

[52] term " IMM " is interpreted as being meant the three-dimensional refractive index mixture model, and wherein periodic thin isotropic refractive index structure is described to the twin shaft birefringent layers that has effective principal refractive index along x, y, z refractive index curve direction.

[53] term " RCWA " is interpreted as being meant accurate coupled waves analysis, and it adopts the vector diffraction equation to solve the boundary condition of diffraction structure, and this diffraction structure has the width and the depth profile of illumination wavelengths grade.

[54] term " A-panel " is understood to include the retarder element that plane that its C-axle is parallel to this device is oriented.

[55] term " C-panel " is understood to include its C-axle and is parallel to the retarder element that this device normal direction is oriented.

[56] term " in the face " is interpreted as being described as being parallel to the plane of device, for example delay in birefringence in the face, the face, the interior delayer axle of face etc.

[57] term " face is outer " is interpreted as being described as being parallel to the device normal, for example outer birefringence of face, face external delays etc.

[58] term " delay or postpone " is interpreted as being meant the multiplying each other of thickness of the difference of two orthogonal indices and optical element.

[59] term " face in postpone " is interpreted as being meant the difference of refractive index in the face of two quadratures and the product of optical element thickness.

[60] term " face external delays " is interpreted as being meant refractive index and the difference of an interior refractive index of face and the product of optical element physical thickness along optical element thickness direction (z direction).Perhaps, this term can be regarded as the difference that is meant the mean value of refractive index in the refractive index of optical element thickness direction (z direction) and the face and the product of optical element physical thickness.

[61] term " birefringence " is interpreted as being meant and has a plurality of different refractive indexes.

[62] term " single shaft " is interpreted as being meant and has two different refractive indexes (for example, two among nx, ny and the nz equate basically at least).

[63] term " polarizer " is understood to include the device that is commonly referred to " analyzer ".

[64] term " horizontal non-homogeneous grating " is understood to include the structure that has periodic refractive index modulation (and modulate mutually the position) on the direction of device plane being parallel to.

[65] term " axial non-homogeneous grating " is understood to include the structure that has periodic refractive index modulation (and phase modulation (PM)) on the direction that is parallel to the device normal.

Description of drawings

[66] according to following detailed instructions, in conjunction with the accompanying drawings, more feature and advantage of the present invention will become clear, wherein:

[67] Fig. 1 be prior art, based on the synoptic diagram of liquid crystal over silicon (LCoS) projection light engines of 3-panel wire-grid polarizer (WGP);

[68] Fig. 2 illustrates twice and passes LCoS panel and adjustment delayer, the maintenance of linear polarization;

[69] Fig. 3 is LCoS panel and the synoptic diagram of adjusting the relative orientations arc angular range of delayer slow axis;

[70] Fig. 4 is illustrated in the one-dimensional grating structure in the circular cone assembly bench;

[71] Fig. 5 illustrates the effective A-panel delayer with negative form birefringent;

[72] Fig. 6 is the synoptic diagram with light delay device of horizontal non-homogeneous form birefringent grating;

[73] Fig. 7 is the enlarged drawing of horizontal non-homogeneous form birefringent grating;

[74] Fig. 8 is the synoptic diagram that comprises the global function light delay device of axial non-homogeneous form birefringent grating;

[75] Fig. 9 is the enlarged drawing of axial non-homogeneous form birefringent grating;

[76] Figure 10 illustrates the effectively negative C-panel delayer with negative form birefringent;

[77] Figure 11 is the synoptic diagram of global function grating trim retarders according to an embodiment of the invention; Be included in the non-homogeneous cascade of laterally non-homogeneous (A-panel) and axially non-homogeneous (C-panel) the form birefringent element on the opposite side of substrate;

[78] Figure 12 illustrates modular pair of optical path modulation of A-panel-form birefringence element;

[79] Figure 13 illustrates and is used for the modular minimum grating pitch length that visible band is used;

[80] Figure 14 illustrates interior delay of the significant surface that is used for some modular binary dielectric/airlight grid delay devices that GSolver calculates;

[81] Figure 15 is the synoptic diagram of global function grating trim retarders in accordance with another embodiment of the present invention; Be included in the non-homogeneous cascade of laterally non-homogeneous (A-panel) and axially non-homogeneous (C-panel) the form birefringent element on the same side of substrate;

[82] Figure 16 is the synoptic diagram of global function grating trim retarders in accordance with another embodiment of the present invention, is included in the non-homogeneous cascade of laterally non-homogeneous (A-panel) and axially non-homogeneous (C-panel) form birefringent element and axially non-homogeneous (C-panel) form birefringent element on the opposite side of substrate of a side of substrate;

[83] Figure 17 is the synoptic diagram of global function grating trim retarders in accordance with another embodiment of the present invention, comprise laterally non-homogeneous (A-panel) the form birefringent element that is positioned at same position with axial non-homogeneous (C-panel) form birefringent element, the both is positioned at the same side of substrate;

[84] Figure 18 is the synoptic diagram of global function grating trim retarders in accordance with another embodiment of the present invention, it is meant the FBAR of etching, comprise laterally non-homogeneous (A-panel) the form birefringent element that is positioned at same position with axial non-homogeneous (C-panel) form birefringent element, the both is positioned at the same side of substrate;

[85] Figure 19 illustrates along effective slow axis (bottom) that is similar to etching FBAR coating shown in Figure 180 and the effectively clean delay distribution of fast axle (top), and by modelling so that 20% dutycycle, the height of 130nm and the cycle of 200nm to be provided.

[86] Figure 20 illustrate with λ=550nm place-nominal of 250nm-C-postpone design, adopt GSolver (bottom dotted line) to calculate and the A-panel of FBAR coating that postpones the etching of (top " o " line) as EMT postpones;

[87] Figure 21 a illustrates the compensation leakage intensity that etching FBAR adjusts the cascade of delayer and VAN pattern LCoS panel, and more specifically, the binary channels forward direction that illustrates with respect to the visual angle leaks;

[88] Figure 21 b illustrates the compensation that etching FBAR adjusts the cascade of delayer and VAN pattern LCoS panel and leaks intensity, more specifically, illustrates separately with respect to the backreflection of the adjustment delayer at visual angle and leaks;

[89] Figure 22 a is the clean linear delay figure that postpones of binary channels that the relative visual angle of etching FBAR is shown;

[90] Figure 22 b is the clean linear delay figure that postpones of binary channels that the VAN pattern LCoS type with the delay of 2/250nm A/-C-panel is shown;

[91] Figure 23 a is the linear delay figure (that is, display system postpones only) that the binary channels residual retardance component of two step FBAR/BBAR of etchings and VAN pattern LCoS panel is shown;

[92] Figure 23 b illustrates the FBAR/BBAR of two step etchings and the slow axis orientation of VAN pattern LCoS panel;

[93] Figure 24 is the synoptic diagram of global function grating trim retarders according to another embodiment of the invention, and the film that replaces when top is that it is called as etching BBAR when being wideband A R coating;

[94] Figure 25 illustrates the A-panel delay of adopting GSolver (dotted line) to calculate and postponing the etching BBAR coating of (" o " line) as EMT, wherein SiO ₂The dutycycle of/air dielectric grid is 20%, highly be 200nm for 130nm, cycle;

[95] Figure 26 a illustrates the compensation leakage intensity that etching BBAR/FBAR adjusts the cascade of delayer and VAN pattern LCoS panel, and more specifically, the binary channels forward direction that relative visual angle is shown leaks;

[96] Figure 26 b illustrates the compensation leakage intensity that etching BBAR/FBAR adjusts the cascade of delayer and VAN pattern LCoS panel, more specifically, the backreflection at visual angle relatively is shown separately leaks;

[97] Figure 27 illustrates the A-panel delay of adopting GSolver (dotted line) to calculate and postponing the etching BBAR coating of (" o " line) as EMT, wherein SiO ₂The dutycycle of/air dielectric grid is 50%, highly be 200nm for 65nm, cycle;

[98] Figure 28 a illustrates the compensation leakage intensity that etching BBAR/FBAR adjusts the cascade of delayer and VAN pattern LCoS panel, and more specifically, the binary channels forward direction that relative visual angle is shown leaks;

[99] Figure 28 b illustrates the compensation leakage intensity that etching BBAR/FBAR adjusts the cascade of delayer and VAN pattern LCoS panel, more specifically, the backreflection at visual angle relatively is shown separately leaks;

[100] Figure 29 illustrates and has dutycycle and be 20%, highly be the SiO of 200nm for 130nm, cycle ₂The normal incidence reflectance spectrum of the etching BBAR of/air dielectric grid, this figure comprise and penetrate (Rpp and Rss) reflectance spectrum and cross polarization (Pps and Rsp) reflectance spectrum;

[101] Figure 30 illustrates and has dutycycle and be 50%, highly be the SiO of 200nm for 65nm, cycle ₂The normal incidence reflectance spectrum of the etching BBAR of/air dielectric grid, this figure comprise and penetrate (Rpp and Rss) reflectance spectrum and cross polarization (Rps and Rsp) reflectance spectrum;

[102] Figure 31 is illustrated in given dutycycle and sentences SiO ₂With EMT refractive index (top) and the birefringence (bottom) of air as the binary raster of component material;

[103] Figure 32 illustrates the A-panel delay of adopting GSolver (dotted line) to calculate and postponing the etching BBAR coating of (" o " line) as EMT, wherein SiO ₂/ Al ₂O ₃The dutycycle of dielectric grid is 50%, highly is 610nm, and the cycle is 200nm;

[104] Figure 33 illustrates that to have dutycycle be 50%, highly is 610nm, and the cycle is the SiO of 200nm ₂/ Al ₂O ₃The normal incidence reflectance spectrum of the etching BBAR of dielectric grid, this figure comprise and penetrate (Rpp and Rss) reflectance spectrum and cross polarization (Rps and Rsp) reflectance spectrum;

[105] Figure 34 a illustrates etching SiO ₂/ Al ₂O ₃BBAR/FBAR adjusts the compensation leakage intensity of the cascade of delayer and VAN pattern LCoS panel, and more specifically, the binary channels forward direction that relative visual angle is shown leaks;

[106] Figure 34 b illustrates etching SiO ₂/ Al ₂O ₃BBAR/FBAR adjusts the compensation leakage intensity of the cascade of delayer and VAN pattern LCoS panel, more specifically, the backreflection of the TR at visual angle relatively is shown separately leaks;

[107] Figure 35 illustrates the synoptic diagram of global function grating trim retarders according to another embodiment of the present invention, this delayer is included in the non-homogeneous cascade of laterally non-homogeneous (A-panel) and axially non-homogeneous (C-panel) the form birefringent element in the flaky texture, each birefringence element of coating on the substrate that separates;

[108] Figure 36 illustrates the synoptic diagram of global function grating trim retarders according to another embodiment of the present invention, wherein this grating delayer is integrated in the cover glass of LCoS panel, and wherein this grating delayer has laterally (A-panel) and axially non-homogeneous (but relevant) cascade of (C-panel) form birefringent element;

[109] Figure 37 illustrates the synoptic diagram of global function grating trim retarders according to another embodiment of the present invention, wherein this grating delayer is integrated in the cover glass of LCoS panel, and wherein this grating delayer has laterally non-homogeneous (A-panel) and the non-homogeneous cascade that accounts for axially non-homogeneous (C-panel) form birefringent element of same position;

[110] Figure 38 transmissivity that calculates and transmission of being illustrated in the coated film system of being made by the low-index material unit of the high-index material of the 30nm of 10 pairs of repetitions and 50nm at 45 ° of incident angle places postpones;

[111] Figure 39 is the binary raster synoptic diagram of the etching on the etching terminal;

[112] Figure 40 is the synoptic diagram of etch substrate;

[113] Figure 41 illustrates birefringence in the simulation significant surface of the thin binary raster that is installed on float glass process Pyrex (Borofloat) substrate, is made by 50% float glass process borosilicate (Borofloat) glass and 50% air.

[114] Figure 42 is the synoptic diagram that the book of effective form birefringent layers is piled up (book-stack) model;

[115] Figure 43 is the synoptic diagram of the 3D form birefringent model of A-panel grating;

[116] Figure 44 is the synoptic diagram of effective twin shaft A-panel of glimmer grid;

[117] Figure 45 a is illustrated in the transmission spectrum of match 40nm float glass process Pyrex (the Borofloat)/air glimmer grid on float glass process Pyrex (Borofloat) substrate;

[118] Figure 45 b is illustrated in the thin grating reflection of match 40nm float glass process Pyrex (Borofloat)/air on float glass process Pyrex (Borofloat) substrate;

[119] Figure 45 c is illustrated in the radiotransparency delay of match 40nm float glass process Pyrex (the Borofloat)/air glimmer grid on float glass process Pyrex (Borofloat) substrate;

[120] Figure 45 d is illustrated in the reflection linear delay of match 40nm float glass process Pyrex (the Borofloat)/air glimmer grid on float glass process Pyrex (Borofloat) substrate;

[121] radiotransparency with respect to incident angle that illustrates for 40nm float glass process Pyrex (the Borofloat)/air grating that adopts EMT result and new IMM equivalent layer of Figure 46 postpones to distribute;

[122] Figure 47 illustrates according in the face of the binary raster of EMT and IMM model and the outer birefringence of face;

[123] Figure 48 is the synoptic diagram of global function grating trim retarders according to an embodiment of the invention, and this delayer comprises and is coated in the lip-deep form birefringent membrane system of reticulate pattern (textured) and is applied in the 2nd AR on the second surface;

[124] Figure 49 is the synoptic diagram of global function grating trim retarders in accordance with another embodiment of the present invention, and this delayer comprises the form birefringent membrane system that is coated on first net grain surface and is applied in the second form birefringent membrane system on the second surface;

[125] Figure 50 is illustrated in 12 ° and locates along the plane that is parallel to grating vector with the modeled of unpolarized incident and total reflection of measuring;

[126] Figure 51 transmission that measures that the coating grating of (also along with perpendicular to grid stroke) is shown along fast axial plane and slow axis plane postpones to distribute;

[127] Figure 52 (a) illustrates initial master grating (seed grating) height between 25nm and 50nm and adopt the transmission delay spectrum that measures of grating of some band coatings of different FBAR designs;

[128] Figure 52 (b) illustrates the delay result corresponding to the measurement shown in Figure 52 (a), and initial master grating height some between 25nm and 50nm are the transmission delay spectrum that measures of the grating of band coating not;

[129] Figure 53 illustrates ruddiness, green glow and blue wave band VAN pattern LCoS photo engine contrast;

[130] Figure 54 is the synoptic diagram of global function grating trim retarders according to another embodiment of the present invention, and this global function grating trim retarders comprises the form birefringent membrane system that is coated on first net grain surface and is applied in the 2nd AR on second net grain surface; And

[131] Figure 55 is the synoptic diagram of global function grating trim retarders according to another embodiment of the present invention, and this delayer comprises the form birefringent membrane system on first net grain surface that is coated in the part cover glass that forms display panel.

[132] should be noted that similar elements is represented by same reference numbers in whole accompanying drawing.

Embodiment

[133], global function A/-C-panel grating trim retarders according to an embodiment of the invention is shown with reference to Figure 11.This global function A/-C-panel grating trim retarders 400 comprises horizontal non-homogeneous A-panel light grid element 410 and axially non-homogeneous-C-panel light grid element 450, and each optical grating element all (inherently) is connected to the apparent surface of transparency carrier 490.More specifically, horizontal non-homogeneous A-panel light grid element 410 is installed on the first surface of transparency carrier 490, and axially non-homogeneous-C-panel light grid element 450 is installed on the second surface of transparency carrier 490, this horizontal non-homogeneous A-panel light grid element 410 is grating antireflection (AR) elements, and this axially non-homogeneous-C-panel light grid element 450 is form birefringent antireflection (FBAR) elements.

[134] A-panel grating AR element 410 comprise horizontal raster 420, optionally etching to stop film be 421 (for example, comprise one deck or more multi-layered etch stop layer), optionally epiphragma is 422 (for example, comprise one deck or more multi-layered) and outside surface AR film be 423 (for example, comprising one deck or more multi-layered).Horizontal raster 420 comprises more than first zone 430, and each zone all has w ₁First width and in first total phase delay at normal incidence place, more than 430 and second zones, more than first zone 440 alternately, each of these more than second regional 440 all has w ₂Second width and in second total phase delay at normal incidence place.Preferably, the width w of first area ₁Width w with second area ₂The mark (fraction) that is operation wavelength is with the way of realization birefringence effect.For example, for the 380nm-800nm wave band, dutycycle between 20%-80%, pitch (pitch) between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Obviously, just these parameters are described for the purpose of example.Select other wave band, dutycycle and/or pitch according to concrete application.For example, provide the raster pitch of about 400nm will make light delay device can be used as the zero level sub-wave length grating of 780nm-1550nm wave band.In these cases, can increase the grating height with in the face of 100nm, postponing of realizing expecting, and it is high especially to make the grating height compare with the raster mode width up to about 400nm.For normal incident light, all comprise two or more different light path zones each modulation period, the result, horizontal raster 420 generally needs two or more materials.First kind of material is used for more than first zone 430, and second kind of material is used for more than second zone 440.Under the simplest situation, first kind of material is solid, and second kind of material is air, another kind of gas or vacuum.At this moment, zone 430 forms a plurality of stylobates (wall) more than first, more than second zone 440 are air-gaps so that viewgraph of cross-section corresponding to stylobate groove cycle face shape.Replacedly, first and second kinds of materials all are solids, and selected with the first area 430 that is provided at the normal incidence place and the optical path difference between the second area 440.When first and second kinds of materials all are solid, can adopt above-mentioned etching technics to make grating, perhaps adopt to be exposed to relevant UV light beam and to get off to make grating.Usually select first and second kinds of materials and width w ₁And w ₂So that this structure forms one dimension, the zero level sub-wave length grating that form birefringent in the face is provided.For first and/or second kind of material, suitable solid material comprises organic and inorganic dielectric.For example, Chang Yong dielectric thin film coatings material comprise such as SiO ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium, for example MgF ₂The metal oxide of fluoride, sulfide, silicon nitride etc.Alternatively, first and/or second material comprises assembly of thin films (multi-layer stack).The method that a kind of manufacturing has an A-panel grating of the groove that multilayer film fills comprise etch these grooves with diffraction pattern is provided, the multilayer film of deposition conformal on the substrate of patterning and polish whole film so that desired structure to be provided.The use of multilayer film stylobate makes total A-panel postpone dispersion surface shape and is corrected (for example, achromatic on wide wavestrip).

[135] although the viewgraph of cross-section of horizontal raster 420 is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, adopt two or more shapes.

[136] similarly, although horizontal raster structure 420 is described to the one-dimensional grating structure, and have clear and definite slow axis that comprises delayer in the significant surface and fast axle the orthogonal orientation angular direction the two-dimensional grating structure also within the scope of the invention.Postpone in the face to provide by the difference of the interior length of delay of face of (for example 90 ° of crossing A-panel gratings) along two orthogonal orientation angular direction.For two-dimentional A-panel grating arbitrarily, in non-90 ° of grating vector skews place, can determine along a pair of fast/the clean A-panel of slow axis postpones.If a plurality of A-panel gratings (one dimension or two-dimensional grating) are distributed on a plurality of thickness parts, produce three-dimensional A-panel grating.Similarly, postpone in washing one's face and fast/slow axis can be determined.

[137]-C-panel FBAR element 450 comprises that the refractive index alternate films is 460, the external refractive index match block 461 and inner refractive index match block 462.Axial-periodic structure 460 comprises first multilayer 470, and every layer all has first refractive index n ₁With first thickness d ₁, being arranged alternately with second multilayer 480, every layer of this second multilayer 480 all has second refractive index n ₂With second thickness d ₂Preferably ,-the bed thickness d of first multilayer in the C-panel grating ₁Bed thickness d with second multilayer ₂Be that (for example the mark of λ=550nm) is to provide one-dimensional grating structure and way of realization birefringence effect for operation wavelength.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.For the 380nm-800nm wave band, dutycycle between 20%-80%, the bed thickness d of refractive index alternate films system ₁Or d ₂Generally much larger than about 1nm and much smaller than about 100nm.Obviously, bed thickness d ₁Or d ₂Along with dutycycle and/or wave band and change.For example, although for about 50% dutycycle, bed thickness d ₁Or d ₂Be generally less than about 70nm, but for the narrow wavelength coverage near 800nm, bed thickness will reach about 200nm.When dutycycle generally between 5%-95%, by with bed thickness d ₁Or d ₂Elect similar basically or identical (for example, dutycycle is near about 50%) as, form birefringent is maximized usually.Therefore, more common dutycycle is at 20%-80%, and is perhaps more common at 30%-70%.Although alternate films is 460 to be illustrated as only two-layer different layer material, adopt also within the scope of the invention more than two kinds of different layer materials.First and/or the material that is fit to of the second layer comprise organic and inorganic dielectric matter.n ₁And n ₂Between bigger difference (, being preferably greater than 0.7) for example greater than 0.5 generally will maximize form birefringent and minimize the thickness of coating.For example, comprise 71 pairs of tantalums and silicon layer-C-panel grating estimated that these tantalum layers and silicon layer have nominal index of refraction 2.20 and 1.46 respectively at λ=550nm place to be provided at ± the clean delay of pact-6.3nm at the angle places that inject air of 12 degree.

[138] FBAR element 450 is provided at the insignificant delay in normal incidence place.In oblique incidence place, FBAR element 450 is realized the mark that its nominal-C-panel postpones.FBAR element 450 plays the effect of C tangent plane single axial birefringence element effectively, and its optical axis is parallel to the equipment access normal orientation.

[139] each-C-panel and A-panel light grid element in, AR layer 423,421,461 and 462 all is added at the interface to reduce the material interface reflection.These AR coatings play the effect at the refractive index match layer at the interface of refractive index sudden change.The AR coating also provides extra face external delays component, and this face external delays component should be included in total delay and the phase differential when making grating trim retarders.It is 421 that selectable, as can to comprise one or more layers etching stops film, and selectable, as can to comprise one or more layers cap rock (cap-stack) 422, normally needs for etched diffraction grating.Usually, therefore cap rock can not inserted in the space between the wall basically by oblique evaporation.Glass substrate 490 generally is parallel plane face glass substrate, and it is for example thick for about 1mm.Replacedly, substrate is made by other transparent materials that mechanical support is provided.

[140] the A-panel grating AR element of being made by multi-layer thin rete uniform, patterning 410 all is basic AR functional block with the FBAR element 450 that comprises refractive index alternate multi-layered film system and relevant refractive index match layer.Term " A-panel grating " is meant the optical grating construction that postpones (major function) in the generation face and generally have negative effective birefringence (that is ,-A-panel component) in this application.Term " C-panel grating " is meant generation face external delays and generally has the optical grating construction of negative effective birefringence (that is ,-C-panel component) in this application.Optionally, A-panel grating also produces second external delays.

[141] adopt the A-panel of horizontal raster (being surface relief structure) postpone to go to compensate FBAR film system-the C-panel postpones to advantageously provide in the display surface and the adjustment delayer of face external delays, and therefore be applicable to the residual retardance that compensates the LCD panel, particularly use the residual retardance of the LCD panel in projection application.

[142] in addition, made by isotropic material (promptly not needing the molecular briefringence material) fully easily because this global function A/-C-panel is adjusted delayer, the scope of suitable manufactured materials is quite wide and can select to be fit to the layer material of specific demand.For example, (that is, high flux the demand of) strictness is adjusted delayer easily fully by the inorganic dielectric layer manufacturing in order to satisfy high temperature, high-brightness environment based on the optical projection system of polarization.Advantageously, the employing of inorganic dielectric layer also allows the selective refraction rate to adjust delayer and/or control cross polarization reflectance so that low reflection to be provided.

[143] global function C/A panel adjustment delayer 400 can be made into model.To the Model Calculation of the A-panel grating binary diffraction pattern that a plurality of stylobates (wall) and a plurality of air-gaps replace that is done-is assumed to be.The synoptic diagram of the required lateral light paths modulation of the panel of A-shown in Figure 12 grating.The difference of the total phase delay in the total phase delay in first grating region (stylobate) and second grating region (groove that atmosphere is filled) produces horizontal raster (index modulation with Δ (nh)), wherein, these two zones are located at same physical height h (being that airspace is considered to optical layers).When the pitch of this grating is sub-wavelength, can obtain along effective extraordinary refractive index of grating vector with perpendicular to effective ordinary refractive index of grating vector.Form birefringent effect that Here it is.The difference of effective refractive index produces the A-panel and postpones.Calculate refractive index in the approximate significant surface of A-panel grating 410 by the dutycycle of considering binary modulation, the dutycycle of this binary modulation is based on the width w of first modulation areas ₁Width w with second modulation areas ₂, grating height h, and by using formula (1) and (3).

[144] these model hypothesis binary grid are mounted on the transparency carrier, (that is, the refractive index at λ=550nm place is 1.65 Al not possess the aluminium oxide of etch stop layer, cap rock or other AR layers ₂O ₃) grid.Model result described herein is calculated by the full vector RCWA grating counter of GSolver (by Grating Solver Development Company, Allen, Texas, 4.20b version).The complex amplitude of zero level transmission and reflection has been used for postponing to calculate.The oxidation alum gate is fixed on 47% place of raster pitch, and pitch changes between 100nm-500nm.The height stuck-at-70nm of aluminium oxide stylobate.Figure 13 shows the visible waveband for 400nm-700nm (near band edge), and zero level transmission (0T is in last figure) and reflection (OR is in figure below) distribute to raster pitch length.Remaining level in GSolver calculates is ± 20, and adopted the total dispersion data of aluminium oxide and Corning 1737F glass substrate.Obviously, at about 50: 50 dutycycle place, grating length must be less than the zero order light matrix effect of about 250nm to realize using for from the whole visible waveband of 400nm wavelength or longer beginning.Parallel and vertical polarization input is meant the linear polarization that is parallel and perpendicular to grating vector (promptly vertical respectively and parallel and line direction).At given raster pitch place, for zero level, vertical polarization input is diffracted into the multistage of diffraction efficiency with reduction, and its diffraction is more much harder than the parallel polarization input.In real system is used, can not guarantee incident polarization be linear and parallel/perpendicular to grating vector (position angle that promptly comprises taper incident and delayer is synchronous).

[145], has the monox (SiO of 53%, 47% and 53% dutycycle respectively with reference to Figure 14 ₂), aluminium oxide (Al ₂O ₃) and tantalum oxide (Ta ₂O ₅) postpone result of calculation in the face of dielectric grid and be illustrated.The air-gap between the dielectric grid line, the A-panel raster pitch of 150nm, the stylobate height of 170nm calculate-are supposed in the interior delay of the face that adopts GSolver to obtain.Nominal index of refraction at monox, aluminium oxide and the tantalum oxide at λ=550nm place is respectively 1.485,1.66,2.18.Monox, aluminium oxide and the titania meterial of total dispersion have been adopted.The result shows dielectric/air grating at λ=550nm place, and the A-panel that produces about 14nm, 24nm and 67nm for monox, aluminium oxide and titanium dioxide dielectric/air grille equipment respectively postpones.Typical VAN pattern of length of delay adequate remedy and twisted nematic (TN) LCoS panel in these faces.In fact, postpone in A-panel delayer and the LCoS face not match unsatisfactory be because tuning curve (rotation of the contrast relative bearing) extrasensitivity that is produced.Yet highly effectively birefringent use is relevant with the reflection of polarization that highly intersects in the face.These results represent that clearly dielectric grid makes A-panel delay element have in the face of enough delays with the LCoS panel remnants of compensate for typical and postpones.

[146] whole contrast strengthens the low reflection of general demand side external delays compensation and whole adjustment delayer compensator element.The example of the Model Calculation of right-C-panel grating is disclosed in US patent disclosure No.20050128391A1.By the dutycycle of considering binary modulation calculate and adopt in the approximate significant surface of formula (1) and (4) calculatings-C-panel grating 450/face outside refractive index, the dutycycle of this binary modulation is respectively based on the bed thickness d of first and second multilayers in the refractive index alternate films is ₁And d ₂

[147] with reference to Figure 15, it illustrates global function A/-C-panel grating trim retarders according to another embodiment of the present invention.This global function A/-C-panel grating trim retarders 500 comprise A-panel light grid element 510 ,-C-panel light grid element 530, transparency carrier 540 and AR coating 545.More specifically, A-panel light grid element 510 and-C-panel light grid element 530 relevant couplings and being arranged on the first surface of transparency carrier 540, and AR coating 545 is arranged on the second surface of transparency carrier 540.

[148] A-panel light grid element 510 comprises laterally heterogeneous, periodic refractive index modulator element 515, and this modulator element 515 is provided with selectable cap rock 516 and outside surface AR film is 517.This periodic refractive index modulator element 515 comprises more than first zones 520 that replace with more than second zones 525, wherein, is respectively applied for the material and the width w of first area 520 and second area 525 ₁And w ₂It is selected so that this structure forms the zero level sub-wave length grating that form birefringent in the face is provided.For example, at the 380nm-800nm wave band, dutycycle between 20%-80%, pitch between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Be applicable to first and/or some examples of the material of second kind of material comprise atmosphere, organic dielectric, inorganic dielectric, this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), fluoride (MgF for example ₂), sulfide and nitride (for example silicon nitride).Alternatively, first and/or second material comprises assembly of thin films.A kind of manufacture method that comprises the A-panel grating of assembly of thin films comprise etch a plurality of grooves with diffraction pattern is provided, the assembly of thin films of deposition conformal on the substrate of patterning, the whole film of polishing system to be to provide desired structure, sedimentary veneer and deposit outside surface AR film system alternatively.The use of assembly of thin films advantageously makes total A-panel postpone dispersion surface shape and is corrected (for example, achromatism on wide wavestrip).Although the viewgraph of cross-section of periodic structure is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, adopt two or more shapes.

[149]-C-panel light grid element 530 comprises that being coupled to refractive index matching film is that 536 and 537 axially heterogeneous, refractive index are periodic modulation element 535.This axial cyclic element 535 comprises first multilayer, and every layer all has first refractive index and first thickness, is arranged alternately with second multilayer, and every layer of this second multilayer all has second refractive index and second thickness.Select in first and second multilayers every layer material and bed thickness to provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all much larger than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two-layer different layer material, adopt also within the scope of the invention more than two kinds of different layer materials.First and/or the material that is fit to of the second layer comprise organic and inorganic dielectric matter.

[150] each-C-panel and A-panel light grid element in, AR layer 517,537,536 and 545 all is added on the interface to reduce the material interface reflection.These AR coatings play the effect at the refractive index match layer at the interface of refractive index sudden change.The AR coating also provides extra face external delays component, and this face external delays component will be included in total delay and the phase differential when making grating trim retarders.The selectable cap rock 516 that comprises one or more layers normally needs for dielectric/atmosphere grid etched diffraction grating.Usually, therefore cap rock can not inserted in the space between the wall basically by oblique evaporation.Glass substrate generally is parallel plane face glass substrate, and it is for example thick for about 1mm.Replacedly, substrate is made by other transparent materials that mechanical support is provided.

[151] element 510 and 530 relevant cascade form and advantageously provide in the display surface and the total AR film system of the compensating element, of face external delays, these two elements all are connected to a side of transparency carrier, and therefore be applicable to the residual retardance that compensates the LCD panel, particularly use the residual retardance of the LCD panel in projection application.

[152] in addition, made by isotropic material (promptly not needing the molecular briefringence material) fully easily because the global function A/-C-panel that produced is adjusted delayer, the scope of suitable manufactured materials is quite wide and can select to be fit to the layer material of specific demand.For example, (that is, high flux the demand of) strictness is adjusted delayer easily fully by the inorganic dielectric layer manufacturing in order to satisfy high temperature, high-brightness environment based on the optical projection system of polarization.Advantageously, the employing of inorganic dielectric layer also makes it possible to the selective refraction rate and adjusts delayer and/or the reflection of control cross polarization so that low reflection to be provided.

[153] with reference to Figure 16, it illustrates global function A/-C-panel grating trim retarders according to another embodiment of the present invention.This global function A/-C-panel grating trim retarders 550 comprises that the A-panel light grid element 560 on the first surface that is positioned at transparency carrier 590, the first form birefringent AR film that is positioned on the A-panel light grid element 560 are 580.The second form birefringent AR film that is positioned on the opposing second surface of transparency carrier 590 is 585.More specifically, first-C-panel light grid element 580 coherently is bonded to the first surface of A-panel light grid element 560, and second-C-panel light grid element coherently the level be associated on the second surface of transparency carrier 590.

[154] A-panel light grid element 560 comprises that laterally heterogeneous, refractive index is periodic modulation element 565, etch stop layer 566 and cap rock 567, and both are the required layers of optional etching technics for the backs.This periodic refractive index modulator element 565 comprises and more than second more than first zones 570 that zone 575 replaces, and wherein, is respectively applied for the width (w for example of first area 570 and second area 575 ₁And w ₂) and material selected so that this structure forms the zero level sub-wave length grating that form birefringent in the face is provided.For example, at the 380nm-800nm wave band, dutycycle between 20%-80%, pitch between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Some examples that are applicable to the material of first and/or second material comprise air, organic dielectric, inorganic dielectric, and this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), fluoride (MgF for example ₂), sulfide and nitride (for example silicon nitride).Alternatively, first and/or second material comprises assembly of thin films.A kind of manufacture method with A-panel grating of assembly of thin films filling slot comprise etch these grooves with diffraction pattern is provided, the assembly of thin films of deposition conformal on the substrate of patterning, the whole film of polishing system with provide desired structure, and the remaining arbitrarily layer/film of deposition be.The use of assembly of thin films advantageously makes total A-panel postpone dispersion surface shape and is corrected (for example, achromatism on wide wavestrip).Although the viewgraph of cross-section of periodic structure is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, adopt two or more shapes.

[155] first-C-panel light grid element 580 comprise that being coupled to refractive index matching film is that 582 and 583 refractive index alternate films is 581.Similarly, second-C-panel light grid element 585 comprises that being coupled to refractive index matching film is that 587 and 588 refractive index alternate films is 586.The refractive index alternate films be 581 and 586 and film be 360 similar.More specifically, each alternate films is 581 and 586 all to comprise first multilayer, and every layer all has first refractive index and first thickness, is arranged alternately with second multilayer, and every layer of this second multilayer all has second refractive index and second thickness.Select in first and second multilayers every layer material and bed thickness to provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all much larger than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two-layer different layer material, adopt also within the scope of the invention more than two kinds of different layer materials.First and/or the material that is fit to of the second layer comprise organic and inorganic dielectric matter.

[156] each-C-panel and A-panel light grid element in, AR layer 583,582,588 and 587 all is added on the interface to reduce the material interface reflection.These AR coatings play the effect at the refractive index match layer at the interface of refractive index sudden change.The AR coating also provides extra face external delays component, and this face external delays component will be included in total delay and the phase differential when making grating trim retarders.Selectable etch stop layer 566 and cap rock 516 normally need for dielectric/air grille etched diffraction grating, and this etch stop layer and cap rock can comprise one or more layers.Usually, therefore cap rock can not inserted in the space between the wall basically by oblique evaporation.Glass substrate generally is parallel plane face glass substrate, and it is for example thick for about 1mm.Replacedly, substrate is made by other transparent materials that mechanical support is provided.

[157] element 560 and 580 relevant cascade form and advantageously provide in the display surface and the total AR film system of the compensating element, of face external delays, these two elements all are connected to a side of transparency carrier, and therefore be applicable to the residual retardance that compensates the LCD panel, particularly use the residual retardance of the LCD panel in projection application.The incoherent cascade of element 585 provides extra design flexibility and/or mechanical stability.

[158] in addition, made by isotropic material (promptly not needing the molecular briefringence material) fully easily because the global function C/A that produced adjusts delayer, the scope of suitable manufactured materials is quite wide and can select to be fit to the layer material of specific demand.For example, (that is, high flux the demand of) strictness is adjusted delayer easily fully by the inorganic dielectric layer manufacturing in order to satisfy high temperature, high-brightness environment based on the optical projection system of polarization.Preferably, the employing of inorganic dielectric layer also makes it possible to the selective refraction rate and adjusts delayer and/or the reflection of control cross polarization so that low reflection to be provided.

[159] obvious, although first-C-panel light grid element 580 is illustrated as coherently being coupled to the A-panel light grid element 560 that is positioned on its upper surface, also-C-panel light grid element 580 coherently can be coupled to the lower surface of A-panel light grid element 560 so that it is sandwiched between A-panel light grid element 560 and the substrate 590.

[160] in reference Figure 11,15 and 16 described each embodiment, all be by A-panel grating is formed the element that separates and makes the global function grating with-C-panel grating.Replacedly, the manufactured so that A-panel grating of this global function grating and-C-panel grating at least part coincide (promptly in the space, occupying same position).

[161] with reference to Figure 17, it illustrates global function A/-C-panel grating trim retarders in accordance with another embodiment of the present invention.This global function A/-C-panel grating trim retarders 600 comprise A-panel light grid element 610 ,-C-panel light grid element 650, transparency carrier 690 and AR coating 695.More specifically, A-panel light grid element 610 and-even element on the overlapping first surface that is positioned at transparency carrier 690 with formation of C-panel light grid element 650, and AR coating 695 is arranged on the second surface of transparency carrier 690.

[162] A-panel light grid element 610 comprises laterally heterogeneous, periodic refractive index modulator element, and this modulator element comprises more than first zone 620, and each zone all has w ₁First width and in first total phase delay at normal incidence place, more than 620 and second zones, more than first zone 630 alternately, each of these more than second regional 630 all has second width of w2 and in second total phase delay at normal incidence place.Width w ₁And w ₂It is selected so that this modulator element forms the zero level sub-wave length grating that form birefringent in the face is provided.For example, at the 380nm-800nm wave band, dutycycle between 20%-80%, pitch between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Although the viewgraph of cross-section of periodic structure is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, adopt two or more shapes.

[163], be that the groove of h forms more than 620 and second zones 630, more than first zone to form a plurality of degree of depth by etching-C-panel light grid element 650 (before outside surface AR coating 640 is set) according to preferred embodiment.Groove 630 generally is filled with air/atmosphere.Replacedly, these grooves are filled (for example, filling with another kind of dielectric material) contrast of refractive index with reduction grating ridge 620 and grating groove 630, thereby reduce the backreflection that integrated A/-C-panel is adjusted delayer.

[164]-C-panel light grid element 650 comprises that refractive index alternate films system and refractive index matching film are 640 and 660.Refractive index alternate films system comprises first multilayer 670, and every layer all has first refractive index and first thickness d ₁, being arranged alternately with second multilayer 680, every layer of this second multilayer 680 all has second refractive index and second thickness d ₂Select in first multilayer 670 and second multilayer 680 every layer material and bed thickness, provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all much larger than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two-layer different layer material, adopt also within the scope of the invention more than two kinds of different layer materials.First and/or the material that is fit to of the second layer comprise organic and inorganic dielectric matter.Some examples commonly used that are used to form the material of dielectric film layer comprise SiO ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium, MgF ₂, sulfide, silicon nitride.

[165] AR layer 640,660 and 695 all is added at the interface to reduce the material interface reflection.These AR coatings play the effect at the refractive index match layer at the interface of refractive index sudden change.Cap rock 640 also plays the effect of protective seam alternatively.The AR coating provides extra face external delays component, and this face external delays component will be included in total delay and the phase differential when making grating trim retarders.Glass substrate generally is parallel plane face glass substrate, and it is for example thick for about 1mm.Replacedly, substrate is made by other transparent materials that mechanical support is provided.

[166] element 610 and 650 overlapping cascade form and advantageously provide in the display surface and the total AR film system of face external delays, and these two elements all are connected to a side of transparency carrier.More specifically, the sub-wavelength longitudinal refractive index distributes, and comprises more than first alternating layer 670 and 680 in the zone 620, produce form birefringent-C-panel component, and sub-wavelength lateral refraction rate distributes, and comprises zone 620 and 630 alternately, produces form birefringent A-panel component.The FBAR film of composition is not to provide remaining-C-panel to postpone.In VAN pattern LCoS photo engine, LC C-panel postpones often to reach λ ₀/ 2 values.And the A-panel component is relatively lessly at about λ ₀/ 100, λ wherein ₀Be the nominal center wavelength.As a result, the A-panel slot generally is that the thick mark of micron order (supposing typical 1.50 dielectric refractive index and air binary raster) and whole FBAR film system may be several micron thickness.

[167] advantageously, this global function, that uniformly the A/-C-panel is adjusted the manufacturing of delayer is simple relatively and need the material of minimum number.In addition, all made by isotropic material (promptly not needing the molecular briefringence material) easily because the global function C/A that produced adjusts delayer, the scope of suitable manufactured materials is quite wide and can select layer material to adapt to specific demand.For example, (that is, high flux the demand of) strictness is adjusted delayer easily all by the inorganic dielectric manufacturing in order to satisfy high temperature, high-brightness environment based on the optical projection system of polarization.Advantageously, the use of inorganic dielectric layer also makes it possible to the selective refraction rate and adjusts delayer and/or the reflection of control cross polarization so that low reflection to be provided.

[168] with reference to Figure 18, it illustrates global function A/-C-panel grating trim retarders in accordance with another embodiment of the present invention.This global function A/-C-panel grating trim retarders 700 comprise A-panel light grid element 710 ,-C-panel light grid element 730, transparency carrier 740 and AR coating 745.More specifically, A-panel light grid element 710 and-even element on the overlapping first surface that is positioned at transparency carrier 740 with formation of C-panel light grid element 730, and AR coating 745 is set on the second surface of transparency carrier 740.

[169] A-panel light grid element 710 is laterally heterogeneous, periodic refractive index modulator elements, and this modulator element comprises more than first zone 720, and each zone all has w ₁First width and at first total bit phase delay at normal incidence place, more than 720 and second zones, more than first zone 725 alternately, each of these more than second regional 725 all has w ₂Second width and at second total bit phase delay at normal incidence place.Width w ₁And w ₂It is selected so that this modulator element forms the zero utmost point sub-wave length grating that form birefringent in the face is provided.For example, at the 380nm-800nm wave band, dutycycle between 20%-80%, pitch between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Although the viewgraph of cross-section of periodic structure is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, adopt two or more shapes.

[170] according to preferred embodiment, forming a plurality of degree of depth by etching-C-panel light grid element 730 (after outside surface AR coating 737 is set) is that the groove of h forms more than 720 and second zones 725, more than first zone.Preferably, the expection effective refractive index of the layer that will be etched when designing the AR characteristic of FBAR film system is taken into account.For example for general FBAR film system, wherein form at two kinds of materials, outermost layer is SiO in low-high index of refraction system ₂(n=1.485).SiO with 50% dutycycle ₂/ air grille, birefringence is in approximate effective extraordinary refractive index, ordinary refractive index and the face:

n _e=1.1730, n _o=1.2659 and Δ n=-0.093 (5)

[171] obvious, the SiO of 50% dutycycle ₂The big Δ n value of/air dielectric grid provides does not wish the high backreflection that exists in very-high performance LCoS photo engine.Second dielectric material is inserted air-gap so that the birefringence reduction is feasible in total face, and still, the AR coating that the effective mono-axial refractive index that is produced needs to add probably is to be passed to air with A-panel grating.The filling of grating groove and extra AR layer has all increased cost.Replacedly, reduced or increased SiO from 50: 50 ₂The dutycycle of/air grille.For example, 20%SiO ₂The approximate effective single shaft characteristic of stylobate width below the raster pitch ratio provides:

n _e=1.0596, n _o=1.1140 and Δ n=-0.0544 (5)

Because birefringence is lowered in the face, the adjustment delayer that is produced is better for low reflective application.

[172]-C-panel light grid element 730 be comprise refractive index film alternately be 735 and refractive index matching film be 736 and 737 FBAR element.Alternately the refractive index film is 735 to be made of first multilayer that for example replaces with second multilayer, and every layer of this first multilayer all has first refractive index and first thickness, and every layer of this second multilayer all has second refractive index and second thickness.Select in first multilayer and second multilayer every layer material and bed thickness, provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises the layer between about 10-500, and more typical is layer between the 50-110.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although the alternate films of being discussed system only has two-layer different layer material, employing more than two kinds different layers material also within the scope of the invention.Be used for first and/or the suitable material of the second layer comprise organic and inorganic dielectric.Some examples commonly used that are used to form the material of (dielectric) thin layer comprise SiO ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium, MgF ₂, sulfide, silicon nitride.

[173] AR layer 737,736 and 745 is added at the interface to reduce the material interface reflection.These AR coatings are as the refractive index match layer at the interface in the refractive index sudden change.The AR coating provides extra face external delays component, and this face external delays component will be included in total delay and the phasic difference when making grating trim retarders.Glass substrate generally is the parallel glass plate substrate of face, and it is for example thick for about 1mm.Selectively, substrate is made by other transparent materials that mechanical support is provided.

[174] element 710 and 730 overlapping cascade form and advantageously provide in the display surface and the total AR film system of face external delays, and the overlapping cascade of these two elements is coupled to a side of transparency carrier.More specifically, the sub-wavelength longitudinal refractive index distribution that comprises the alternating layer 735 in the individual zone 720 more than first produces form birefringent-C-panel component, and comprises that the sub-wavelength lateral refraction rate distribution of zone 720 alternately and 725 produces form birefringent A-panel component.The FBAR film of patterning is not to provide remaining-C-panel to postpone.In VAN pattern LCoS photo engine, LC C-panel postpones often to reach λ 0/2 value.And the A-panel component is relatively lessly at about λ ₀/ 100, wherein λ 0 is the nominal center wavelength.As a result, the A-panel slot generally is the mark (supposing typical 1.50 dielectric refractive index and air binary raster) of micron thickness and whole FBAR film system may be several micron thickness.

[175] advantageously, this global function, that uniformly the A/-C-panel is adjusted the manufacturing of delayer is simple relatively and need the material of minimum number.In addition, made by isotropic material (promptly not needing the molecular briefringence material) fully easily because the global function C/A that produced adjusts delayer, the scope of suitable manufactured materials is quite wide and can select to be fit to the layer material of specific demand.For example, (that is, high flux the demand of) strictness is adjusted delayer easily all by the inorganic dielectric layer manufacturing in order to satisfy high temperature, high-brightness environment based on the optical projection system of polarization.Advantageously, the use of inorganic dielectric layer also makes it possible to the selective refraction rate and adjusts delayer and/or the reflection of control cross polarization so that low reflection to be provided.

[176] drawn an assessment result on axle and axle of adjusting delayer with reference to the described global function A/-C-panel of Figure 18 among Figure 19 and 20 respectively.Purpose is that the FBAR that nominal-C-of @ λ=550nm-250nm postpones designs generation slow axis (SA) plane and the clean delay distribution of fast axial plane (FA) as shown in figure 19." intersection " is meant along effective slow axis and (trends towards negative value, and grid bearing) and effectively fast axle (trend towards on the occasion of, and grating vector) clean delay distributes, and thin solid line is the film interference Simulation result with A-panel grating layer of being represented by effective mono-axial refractive index.In the interference thin film model, outermost SiO ₂/ air grille is represented with 20% dutycycle by the effective mono-axial refractive index of effective MEDIUM THEORY (EMT).Except that the face external delays, these postpone to distribute and those very couplings that postpone to distribute that produced by GSolver.A-panel grating has 20%SiO ₂The perfect rectangular modulation of dutycycle, 200nm periodic width and 130nm stylobate height distributes.For the design of 490nm and 590nm wave band, less than 0.5nm, this goes up the error that postpones and comprises an EMT layer model that upward postpones that calculates with respect to GSolver the error of delay on required wave band on the axle.These errors are provided by the difference in two curves among Figure 20.，

[177] full dielectric grating trim retarders has been fixed to conical illumination, the SiO of remaining 20% cycle umber (peroid fraction) after the top layer of the FBAR coating of this full dielectric grating trim retarders is etched ₂Grating layer is represented by zero level EMT refractive index.This makes it possible to calculate this numerical value device with 4 * 4 matrix computations programs.Adjust delayer and be designed to have about 6.5nm/-220nm A/-C-panel delay.LCoS postpones expression by 2nm/250nm A/C-, and this 2nm/250nm A/C-postpones to be provided by the outer LC localizer inclination angle of 84.5 ° of faces.This simulation in atmosphere (f/2.4 system) have be parallel to adjust delayer compensator and LCoS level (stage) along the diminished shaft of device normal direction orientation ± carry out on 12 ° of circular cones.The LCoS layer has n respectively at λ=550nm place _o=1.50 and n _e=1.65 refractive index.This adjusts the interior and outer residual retardance of face of face of delayer compensation VAN-LCoS.The cross polarization of binary channels transmission is revealed (by adjusting delayer and LCoS level, be defined as forward direction herein and reveal) and has been modeled as less than 0.006%, and this value on average draws on the circular cone at single wavelength place.This has provided 17,300: 1 forward direction contrast.Do not consider to pass the light component of the adjustment delayer in the first passage, reflection is revealed (only adjust delayer, be defined as reverse leakage herein) total contrast is defined as 18,700: 1.In addition, the obtainable best baseline contrast of the optical element of other in the photo engine (such as polarizer, PBS etc.) decision.For design photo engine preferably, the optimal limit contrast can be 10,000: 1.According to the forward direction of conoscope, oppositely and reveal relevant of baseline and, adopt FBAR after the etching as adjusting delayer, about 36 ° from the toning of intersecting axle orientation, the conoscope system contrast is estimated as 4,700: 1.Draw forward direction among Figure 21 (a) and Figure 21 (b) respectively and oppositely revealed circular cone.

[178] be moved out of from its exemplary position when adjusting delayer, and when the combination that panel is in the high-quality catoptron of closed condition and is in the quarter-wave plate catoptron of open mode substituted, system's baseline contrast was the suitable optical contrast ratio of the taper weighting of this optical system.This baseline takeoff crossed-polarizer and polarization beam apparatus reveal light from axle.The axle of Prepolarization device and delustring polarizer is gone up polarization contrast and can be obtained from the WGP data of being announced.Suppose that WGP only is used as beam splitting device and Prepolarization device and delustring polarizer and is made by the dichroic sheet, be incident on the approximate product by WGP transmission-polarizing contrast and the positive contrast of dichroic transmission sheet of the polarisation of light contrast of adjusting on the delayer so: 450 * 1000 provide.In backward channel, the polarization contrast of WGP reflection is variation significantly, the intersection analyzer is provided 30 * 1000 the last polarization contrast of axle.These two polarization extinction ratios (inverse of polarization contrast) are used as Jones (Jones) vector of input polarization device and output polarization device in 4 * 4 matrix models.System's baseline contrast should be considered the off-axis effect of crossed-polarizer.

[179] Figure 22 (a) and Figure 22 (b) illustrate the binary channels transmission delay figure that adjusts delayer (TR) and LCoS level respectively.The slow axis of LCoS device is oriented at 45 °/-135 ° view plane places.Along this slow axis plane, because+C-panel effect, the clean delay increases away from normal incidence.On the contrary, because-C-panel effect, the clean delay that the slow axis plane of TR postpones (along-9 °/171 ° view planes) reduces away from normal incidence, and combination and their the correlation delay axle figure of this two width of cloth delay figure provide low-down leakage taper intensity.The coherent combination of TR and LCoS level has provided clean the delay and the axle orientation of system as shown in Figure 23 (a) and Figure 23 (b).Optical projection system is had the TR that doubles on the retardation axis that is arranged essentially parallel to main (i.e. " S " and " P ") plane to postpone by surplus.This system is finalized to have apart from the about 1 ° mean axis skew of principal plane.

[180] with reference to Figure 24, it illustrates global function A/-C-panel grating trim retarders according to another embodiment of the present invention.This global function A/-C-panel grating trim retarders 750 comprises A-panel light grid element 760, first-C-panel light grid element 780, transparency carrier 790 and second-C-panel light grid element 785.More specifically, A-panel light grid element 760 and first-C-panel light grid element 780 be overlapping to be positioned at even element on the first surface of transparency carrier 790 with formation, and second-C-panel light grid element 785 (inherently) is connected on the second surface of transparency carrier 790.

[181] A-panel light grid element 760 is laterally heterogeneous, periodic refractive index modulator elements, and this modulator element comprises more than first zone 770, and each zone all has w ₁First width and in first total phase delay at normal incidence place, more than 770 and second zones, more than first zone 775 alternately, each of these more than second regional 775 all has w ₂Second width and in second total phase delay at normal incidence place.Width w ₁And w ₂It is selected so that this modulator element forms the zero utmost point sub-wave length grating that form birefringent in the face is provided.For example, at the 380nm-800nm wave band, dutycycle between 20%-80%, pitch between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Although the viewgraph of cross-section of periodic structure is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, adopt two or more shapes.

[182], be that the groove of h forms more than 770 and second zones 775, more than first zone to form a plurality of degree of depth by etching-C-panel light grid element 650 (after outside surface AR coating 783 is set) according to preferred embodiment.Preferably, when designing the AR characteristic of FBAR film system, the expection effective refractive index of the layer after the etching is taken into account.Groove 775 generally is filled with air, other gas or is in vacuum.Selectively, these grooves are filled with other dielectric material to reduce birefringence in total face.Alternatively, recently reduce birefringence in total face by reduced or increased duty from 50: 50.

[183] first-C-panel light grid element 780 be comprise refractive index film alternately be 781 and refractive index matching film be 782 and 783 FBAR element.Alternately the refractive index film is 781 to be formed by first multilayer that for example replaces with second multilayer, and every layer of this first multilayer all has first refractive index and first thickness, and every layer of this second multilayer all has second refractive index and second thickness.

[184] similar, second-C-panel light grid element 785 be comprise refractive index film alternately be 786 and refractive index matching film be 787 and 788 FBAR element.Alternately the refractive index film is 786 to be formed by first multilayer that for example replaces with second multilayer, and every layer of this first multilayer all has first refractive index and first thickness, and every layer of this second multilayer all has second refractive index and second thickness.

[185], select in first and second multilayers every layer material and bed thickness to provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms to first-C-panel light grid element 780 and second-C-panel light grid element 785 each.Usually, to first-C-panel light grid element 780 and second-C-panel light grid element 785 each, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.To first-C-panel light grid element 780 and second-C-panel light grid element 785 each, every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Dutycycle is generally between 5%-95%, more typically between 20%-80%.Although the alternate films of being discussed system only has two-layer different layer material, adopt also within the scope of the invention more than two kinds of different layer materials.First and/or the material that is fit to of the second layer comprise organic and inorganic dielectric matter.First-C-panel light grid element 780 and second-C-panel light grid element 785 will be made by same material or different materials.Some examples commonly used that are used to form the material of dielectric film layer comprise SiO ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium, MgF ₂, sulfide, silicon nitride.

[186] AR layer 783,782,788 and 787 is added at the interface to reduce the material interface reflection.These AR coatings are as the refractive index match layer at the interface in the refractive index sudden change.The AR coating provides extra face external delays component, and this face external delays component will be included in total delay and the phasic difference when making grating trim retarders.Glass substrate generally is the parallel glass plate substrate of face, and it is for example thick for about 1mm.Selectively, substrate is made by other transparent materials that mechanical support is provided.

[187] element 760 and 780 overlapping cascade form and advantageously provide in the display surface and the total AR film system of face external delays, and these two elements all are connected to a side of transparency carrier.More specifically, the sub-wavelength longitudinal refractive index distribution that comprises the alternating layer 781 in the individual zone 770 more than first produces form birefringent-C-panel component, and comprises that the sub-wavelength lateral refraction rate distribution of zone 770 alternately and 775 produces form birefringent A-panel component.The FBAR film system of the not patterning in first-C-panel light grid element 780 and the second-C-panel light grid element 785 provides remaining-C-panel to postpone.

[188] advantageously, this global function, that uniformly the A/-C-panel is adjusted the manufacturing of delayer is simple relatively and need the material of minimum number.In addition, all made by isotropic material (promptly not needing the molecular briefringence material) easily because the global function C/A that produced adjusts delayer, the scope of suitable manufactured materials is quite wide and can select to be fit to the layer material of specific demand.For example, (that is, high flux the demand of) strictness is adjusted delayer easily all by the inorganic dielectric layer manufacturing in order to satisfy high temperature, high-brightness environment based on the optical projection system of polarization.Advantageously, the use of inorganic dielectric layer also makes it possible to the selective refraction rate and adjusts delayer and/or the reflection of control cross polarization so that low reflection to be provided.Yet, two incoherent couplings-C-panel component 780 and 785 provide produced bigger design flexibility also/or be controlled on the transparency carrier 790 coating stress that uses.

[189] according to another embodiment of the invention, first-C-panel light grid element 780 is replaced by common wideband A R coating (BBAR).At this moment, A-panel light grid element 760 be etched into BBAR coating and A-panel light grid element 760 and-the 785 incoherent couplings of C-panel light grid element.Thereby produce non-homogeneous A/-C-panel delayer.

[190] the BBAR film after the etching is 780 with GSolver typing, postpones in the face to the BBAR after the 420nm-700nm wave band etching shown in Figure 25.A-panel grating has 20%SiO ₂The perfect rectangular modulation of dutycycle, 200nm periodic width and 130nm stylobate height distributes.The axial delay of adopting GSolver (dotted line) to calculate is except very short wavelength place.On the contrary, comprise the product of the pre-measuring tool of Interference Model of EMT layer (" o " line) with Δ nd in the increase face of wavelength increase.For for the nominal 6.5nm of λ=550nm delayer, to compare with the GSolver model, the error of the delay of Interference Model on whole visible waveband is less than 0.7nm.

[191], be included in the 20%SiO that has on first glass surface for the taper performance ₂The grating delayer of BBAR after the etching of dutycycle and the suitable FBAR on relative glass surface (having pact-220nm C-postpones) is finalized.A-panel grating layer is represented by its EMT refractive index.Forward direction and reverse cross polarization leakage intensity are shown respectively in Figure 26 a and 26b.At λ=550nm place, the forward direction contrast reaches about 22,000: 1 and the reverse contrast degree is 16,700: 1.These results are identical with FBAR grating delayer after the etching.Because adopt thick substrate (about 0.7mm) as the coherent optics layer in 4 * 4 simulations, the reverse leakage of conoscope illustrates some stochastic errors.System contrast is estimated 4,900: 1, and system's baseline contrast is 10,000: 1.

[192] though 20%SiO ₂Two simulative examples of the dielectric grid delayer of etching have all been realized birefringence in about 0.05 the face (the physical grating thickness of 130nm and in the delay of λ=6.5nm of 550nm place), can be with 50: 50 SiO ₂/ air grille is with the retroaction typing of Δ n in the big face.With 20%SiO ₂/ air grille (formula 5) is compared, for 50%SiO ₂/ air grille, the Δ n that zero level EMT model prediction is almost double.The normal incidence place is with GSolver this 50% (SiO that finalizes the design on visible waveband ₂/ air) grid.Figure 27 illustrates for the axle of EMT4 * 4 matrixes (" o " line) model and GSolver (dotted line) model and goes up delay.Obviously, the EMT model has obviously been over-evaluated attainable interior birefringence.The thickness of grating layer is 65nm.The EMT model estimates that axle upward postpones to be about 6.5nm, and the GSolver model is given in the only delay of about 4.7nm of λ=550nm place.Therefore Δ n is-4.7/65 or-0.07 in the significant surface.

[193] Δ n place in raised floor shows respectively among Figure 28 (a) and 28 (b) for forward direction and back to the conoscope LCoS compensation of revealing.The first surface of grating delayer is fastened at multilayer AR film has 50%SiO ₂/ air grille, the second surface of grating delayer are rectangle FBAR coatings, provide pact-220nm C-to postpone.The forward direction contrast is 22,700: 1, quite be similar to the BBAR grating delayer of 20% etching.But, when Δ n in the significant surface along with from the increase of the dutycycle of 20%-50% and from approximately-0.05 when increasing to approximately-0.07, the reverse contrast degree is approximate to dividing to 9,000: 1.As the result of low reverse contrast, system contrast is estimated 3,900: 1, and at the SiO of 20% dutycycle ₂Degenerate 20% on the/air grille delayer.

[194] aspect the conoscope contrast performance of estimating all three grating delayer examples, suppose that grating layer is by the EMT model representation of interfering at 4 * 4 matrixes in calculating.This hypothesis is roughly effective.Show 20%SiO among Figure 29 and 30 respectively ₂/ air grille delayer and 50%SiO ₂The normal incidence reflectance spectrum of/air grille delayer.More specifically, the top of Figure 29 illustrates passes (through) (Rpp and Rss) reflectance spectrum, and the bottom of Figure 29 illustrates cross polarization (Rsp and Rps) reflectance spectrum.Similarly, the top of Figure 30 illustrates and penetrates (Rpp and Rss) reflectance spectrum, and the bottom of Figure 30 illustrates cross polarization (Rsp and Rps) reflectance spectrum.Obviously, for two dutycycles, the cross polarization spectrum is overlapping fully.GSolver result draws with " o " mark, and the result of EMT Interference Model draws with ". " mark.SiO ₂The dutycycle of/air dielectric grid is 20%, highly is 130nm, and the cycle is 200nm.Obviously, diffraction model (calculating with GSolver) and 4 * 4 matrix models (calculating by represent thin grating layer with the EMT refractive index) produce detailed reflection trend.According to desirable crossed-polarizer, the cross polarization of these two grating delayers is revealed at λ=550nm place approximate respectively 8e ^-5And 7e ^-4In fact, the existence of illumination circular cone and imperfect crossed-polarizer makes that the backreflection contrast of these two grating delayers is respectively 17,000: 1 and 9,000: 1.

[195] expection needs in the significant surface birefringence to realize high-contrast compensation less than-0.02 grating trim retarders.According to SiO ₂With the binary system of air grille, select to dwindle dutycycle and be restricted as birefringent mode in the reduction face.Figure 31 illustrates birefringent estimation in the significant surface according to the EMT model.SiO ₂The refractive index of material at λ=550nm place is 1.4747.For have can with SiO ₂Any dielectric/air grille of the refractive index of comparing, expection need be less than 10% dutycycle to obtain less than 0.02 | Δ n|.This must produce multiple coordination between grid cycle, grid height and stylobate width (dutycycle).In order to improve the backreflection contrast limit (its cover total system contrast performance and do not consider that the twin-stage compensation renders a service), must be from 20%SiO ₂Birefringence begins further to reduce birefringence in the face in the face that/air grille realizes.Reducing the birefringent mode of effective EMT is with the SiO after the another kind of dielectric material filling etching ₂The groove of layer.

[196] with 50% SiO ₂(nominal index of refraction λ and Al with 1.4747@ λ=550nm ₂O ₃The interior birefringence of significant surface that (nominal index of refraction with 1.6637@ λ=550nm) formed and constituted the double base material system of A-panel grating is-0.0114.The GSolver model is to the thick SiO of 610nm ₂/ Al ₂O ₃Dielectric grid returns～postpones in the face of 6.8nm, and providing effective Δ n is-0.0111.Figure 32 illustrates the transmission delay spectrum of the BBAR with this dielectric grid.The polarization leakage of intersecting on the axle is estimated at 3e ^-6, than unfilled 20%SiO ₂The high order of magnitude of/air grille.Figure 33 illustrates the normal incidence reflection and reveals curve.More specifically, the top of Figure 33 illustrates and penetrates (Rpp and Rss) reflectance spectrum, and the bottom of Figure 33 illustrates cross polarization (Rsp and Rps) reflectance spectrum.The cross polarization spectrum is overlapping fully.GSolver result draws with " o " mark, and the result of EMT Interference Model draws with ". " mark.SiO ₂/ Al ₂O ₃The dutycycle of dielectric grid is 50%, highly is 610nm, and the cycle is 200nm.Grid delay device after using this to fill shown in Figure 34 (a) and 34 (b) and same LCoS model, the twin-stage TR/LCoS result of calculation under the circular cone irradiation.Obviously, be similar to the embodiment 400 among Figure 11, this grating delayer has the SiO that is buried in the wideband A R film system ₂/ Al ₂O ₃Dielectric grid.The FBAR film system that has the 220nmC-delay at λ=550nm place is positioned on the second surface of transparency carrier.Forward direction, oppositely and the total system contrast estimate it is respectively 24,600: 1,165,000: 1 and 6,800: 1.Because suitable light weighting, baseline contrast are 10,000: 1 panchromatic photo engine will be with approximate its green channel contrast 6,800: 1 running.

[197] with reference to Figure 35, it illustrates global function A/-C-panel grating trim retarders according to another embodiment of the present invention.This global function A/-C-panel grating trim retarders 800 comprises the A-panel light grid element 810 that is positioned on first transparency carrier 890 and is positioned on second transparency carrier 891-C-panel light grid element 850 that these two optical grating elements all are connected to each other by glue-line 895.More specifically, A-panel light grid element 810 and-C-panel light grid element 850 cambium layer structures.

[198] A-panel light grid element 810 comprises laterally heterogeneous, periodic refractive index modulator element 820, etching stop film be 821 and optionally outside surface AR film be 822 to be coupling on this modulator element.This periodic refractive index modulator element 820 comprises more than first zones 830 that replace with more than second zones 840, wherein selects the width w of first area 830 and second area 840 ₁And w ₂And material is so that this structure forms the zero utmost point sub-wave length grating that form birefringent in the face is provided.For example, at the 380nm-800nm wave band, dutycycle between 20%-80%, pitch between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Be applicable to first and/or some examples of the material of second kind of material comprise atmosphere, organic dielectric, inorganic dielectric, this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), fluoride (MgF for example ₂), sulfide and nitride (for example silicon nitride).Alternatively, first and/or second material comprises assembly of thin films.A kind of manufacture method that comprises the A-panel grating of assembly of thin films comprise etch a plurality of grooves with diffraction pattern is provided, the assembly of thin films of deposition conformal on the substrate behind the patterning, the whole film of polishing system to be to provide desired structure, sedimentary mantle and deposit outside surface AR film system alternatively.The use of assembly of thin films advantageously makes total A-panel postpone dispersion surface shape and is corrected (for example, achromatism on whole wavestrip).Although the viewgraph of cross-section of periodic structure is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, use two or more shapes.

[199]-C-panel light grid element 850 comprises that being connected to refractive index matching film is 861 and 862 axially heterogeneous, periodic refractive index modulator element 860.This axial cyclic element 860 comprises first multilayer 870, and every layer all has first refractive index and first thickness, is arranged alternately with second multilayer 880, and every layer of this second multilayer all has second refractive index and second thickness.Select in first and second multilayers every layer material and bed thickness to provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can minimize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two kinds of different layer materials, adopt also within the scope of the invention more than two kinds of different layer materials.First and/or the material that is fit to of the second layer comprise organic and inorganic dielectric.

[200] each-C-panel and A-panel light grid element in, AR layer 822,862 and 861 all is added on the interface to reduce the material interface reflection.These AR coatings are as the refractive index match layer at the interface in the refractive index sudden change.The AR coating also provides extra face external delays component, and this face external delays component will be included in total delay and the phase differential when making grating trim retarders.General each glass substrate 890 and 891 all is the parallel face glass substrate of face, and it is for example thick for about 1mm.Selectively, substrate is made by other transparent materials that mechanical support is provided.

[201] element 810 and 850 relevant cascade form and advantageously provide in the display surface and the compensating element, of face external delays, and therefore are applicable to the residual retardance of compensation LCD panel, the residual retardance of the LCD panel that particularly adopts in projection application.In addition, because-C-panel grating do not have retardation axis in the face, and the global function that is produced is adjusted delayer and is not limited to the horizontal orientation error.

[202] because the global function C/A that produced adjusts delayer is all made by isotropic material (promptly not needing the molecular briefringence material) easily, the scope of suitable manufactured materials is quite wide and can select to be fit to the layer material of specific demand.For example, (that is, high flux the demand of) strictness is adjusted delayer easily all by the inorganic dielectric layer manufacturing in order to satisfy high temperature, high-brightness environment based on the optical projection system of polarization.Advantageously, the use of inorganic dielectric layer also makes it possible to the selective refraction rate and adjusts delayer and/or the reflection of control cross polarization so that low reflection to be provided.

[203] in little display projection system of the separative adjustment retarder element of compensation as shown in Figure 2, have at least two unnecessary AR coated surfaces.By a part that make to adjust the delayer assembly and become LCoS or xLCD covered substrate avoided to these AR coatings (that is, adjusting on the delayer for one, one on display panel, face with each other) demand.

[204], the LCoS device 900 that comprises integrated adjustment delayer and display panel covered substrate is shown with reference to Figure 36.A-panel grating/-C-panel grating trim retarders subcomponent 960 comprises the A-panel light grid element 910 of relevant being coupled to-C-panel light grid element 930, the both is arranged on the first surface of transparent covered substrate 990.The second surface of transparent covered substrate 990 forms liquid crystal cells subcomponent 950 with second substrate 995 of display.The top-level metallic reverberator of this adjustment delayer subcomponent 960 on being disposed in silicon backboard (substrate) 995 forms the lc unit gap, and LC molecule 955 is arranged in this cell gap.

[205] A-panel light grid element 910 comprises laterally heterogeneous, periodic refractive index modulator element 915, covering layer film be 916 and outside surface AR film be 917 to be arranged on this modulator element.This horizontal raster element 915 comprises more than first zones 920 that replace with more than second zones 925, wherein selects the width w of first area 920 and second area 9250 ₁And w ₂With material so that this structure forms the zero utmost point sub-wave length grating that form birefringent in the face is provided.For example, at the 380nm-800nm wave band, dutycycle between 20%-80%, pitch between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Be applicable to first and/or some examples of the material of second kind of material comprise atmosphere, organic dielectric, inorganic dielectric, this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), fluoride (MgF for example ₂), sulfide and nitride (for example silicon nitride).Alternatively, first and/or second material comprises assembly of thin films.The use of assembly of thin films advantageously makes total A-panel postpone dispersion surface shape and is corrected (for example, achromatism on whole wavestrip).Although the viewgraph of cross-section of periodic structure is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, adopt two or more shapes.

[206]-C-panel light grid element 930 comprises that being connected to refractive index matching film is 936 and 937 axially heterogeneous, periodic refractive index modulator element 935.This axial cyclic element 935 comprises first multilayer, and every layer all has first refractive index and first thickness, is arranged alternately with second multilayer, and every layer of this second multilayer all has second refractive index and second thickness.Select in first and second multilayers every layer material and bed thickness to provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises the layer between about 10-500, and more typical is layer between about 50-110.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can minimize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two kinds of different layer materials, adopt also within the scope of the invention more than two kinds of different layer materials.First and/or the material that is fit to of the second layer comprise organic and inorganic dielectric.[207] each-C-panel and A-panel light grid element in, AR layer 917,937 and 936 all is added on the interface to reduce the material interface reflection.These AR coatings are as the refractive index match layer at the interface in the refractive index sudden change.The AR coating also provides extra face external delays component, and this face external delays component will be included in total delay and the phase differential when making grating trim retarders.

[208] routinely, liquid crystal cells subcomponent 950 also comprises oriented layer 956 and preceding transparency conductive electrode 957, and this oriented layer for example is the inorganic layer of polymeric layer or inclination evaporation, and this preceding transparency conductive electrode is for example made by tin indium oxide (ITO).Sentence VAN-model LC orientation in pre-tilt angle 970 this LCoS display is shown.According to the overclocking among Fig. 3 (over-clocking) compensation image, relevant LC dip plane generally is not parallel to and also is not orthogonal to grating vector (being shown parallel among Figure 26) and is oriented.Because the use of positive single shaft LC material in pre-tilt and the display, the remaining A/-C-panel that is in the display of light closure state postpones by integrated adjustment delayer compensator 960 compensation.

[209] in order to provide high yield integrated compensator/display, consider the interior delay amplitude of nominal plane of two retarder element, can be offset by the rough position angle that mechanical rotation covered substrate in this device plane applies between (impose) adjustment retarder element 960 and the display element 950.The independent accurate adjustment of each integrated compensator/display can comprise other non-mechanical means, for example LC pitch angle voltage is switched to closed condition and always reveals intensity with further reduction.Be the content of disclosed more on-mechanical accurate adjustment in the US temporary patent application submitted on October 18th, 2005 number 60/727,969.Should be noted that, if the considerable part of the feasible voltage that is applied of ITO layer can be passed the LC layer (promptly, the ITO layer does not insulate with the LC layer basically mutually), so A-panel grating 910 and-C-panel grating 930 elements optionally are distributed to two surfaces of covered substrate 990.

[210], the LCoS device 1000 that comprises integrated grating adjustment delayer and display panel covered substrate is shown with reference to Figure 37.The grating trim retarders subcomponent comprises FBAR coating 1030 and is the A-panel grating 1015 that 1030 outside surface produces by etching FBAR film, FBAR coating 1030 played before any etching of the parallel groove on the coated film-and the effect of C-panel grating.Overlapping A-panel grating and-C-panel light gate region (being that the degree of depth is the zone 1020 and 1025 of h) provides uniform A/-C-panel retarder element.FBAR 1030 after the etching and refractive index matching film are 1036 and 1037 to be disposed in together on the first surface of first transparency carrier 1090.The second surface of transparent covered substrate 1090 forms liquid crystal cells subcomponent 1050 with second substrate 1095 of display.The top-level metallic reverberator of FBAR after the etching on being disposed in silicon backboard (substrate) 1095 forms the lc unit gap, and LC molecule 1 055 is arranged in this cell gap.

[211] A-panel grating 1015 is laterally heterogeneous, periodic refractive index modulator elements, and this modulator element comprises more than first zone 1020, and each zone all has w ₁First width and in first total phase delay at normal incidence place, more than 1020 and second zones, more than first zone 1025 alternately, each of these more than second regional 1025 all has w ₂Second width and in second total phase delay at normal incidence place.Select width w ₁And w ₂So that this modulator element forms the zero utmost point sub-wave length grating that form birefringent in the face is provided.For example, at the 380nm-800nm wave band, dutycycle between 20%-80%, pitch between 100nm-250nm, the first width w ₁With the second width w ₂Generally between 20nm-200nm, modulation height h is generally between 10nm and 3 μ m.Although the viewgraph of cross-section of periodic structure is shown to have binary (rectangle) pattern, other diffraction surfaces shape is also contained within the scope of the present invention.For example, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine or trapezoidal grating pattern.Alternatively, in same A-panel grating, adopt two or more shapes.

[212], form more than 1020 and second zones 1025, more than first zones to form the groove that a plurality of degree of depth are h by etching-C-panel light grid element 1030 (before outside surface AR coating 1037 is provided) according to preferred embodiment.Groove 1025 generally is filled with air/atmosphere.Selectable, fill the contrast of refractive index of (for example) these grooves, thereby reduce the backreflection that integrated A/-C-panel is adjusted delayer with reduction grating ridge 1020 and linear grating groove 1025 with another kind of dielectric material.

[213]-C-panel light grid element 1030 comprises that alternately refractive index film system and refractive index matching film are 1037 and 1036.Alternately refractive index film system comprises first multilayer, and every layer all has first refractive index and first thickness, is arranged alternately with second multilayer, and every layer of this second multilayer all has second refractive index and second thickness.Select in first and second multilayers every layer material and bed thickness to provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can minimize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two kinds of different layer materials, adopt also within the scope of the invention more than two kinds of different layer materials.First and/or the material that is fit to of the second layer comprise organic and inorganic dielectric.Some examples commonly used that are used to form the material of dielectric film layer comprise SiO ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium, MgF ₂, sulfide, silicon nitride.

[214] AR layer 1037 and 1036 is added on the interface to reduce the material interface reflection.These AR coatings are as the refractive index match layer at the interface in the refractive index sudden change.Overlayer 1037 has also played the effect of protective seam alternatively.The AR coating provides extra face external delays component, and this face external delays component will be included in total delay and the phase differential when making grating trim retarders.

[215] routinely, liquid crystal cells subcomponent 1050 also comprises oriented layer 1056 and preceding transparency conductive electrode 1057, and this oriented layer for example is the inorganic layer of polymeric layer or inclination evaporation, and this preceding transparency conductive electrode is for example made by tin indium oxide (ITO).Sentence VAN-model LC orientation in pre-tilt angle 1070 this LCoS display is shown.According to the covering among Fig. 3 coupling compensation image, relevant LC dip plane generally is not parallel to and also is not orthogonal to grating vector (although being shown parallel among Figure 37) and is oriented.Because the use of positive single shaft LC material in pre-tilt and the display, the remaining A/-C-panel that is in the display of light closure state postpones by integrated adjustment delayer compensator 1030 compensation.

[216] element 1015 and 1030 stack cascade form and advantageously provide in the display surface and the total AR film system of the compensating element, of face external delays, these two elements all are coupled to a side of transparency carrier 1090, more specifically, the sub-wavelength longitudinal refractive index distribution that comprises the alternating layer 1035 in the individual zone 1020 more than first produces form birefringent-C-panel component, and comprises that the sub-wavelength lateral refraction rate distribution of zone 1020 alternately and 1025 produces form birefringent A-panel component.The FBAR film of patterning is not to provide remaining-C-panel to postpone.

[217] in reference Figure 17,18,24,37 described the foregoing descriptions, adjustment delayer based on global function A/-C-panel grating comprises horizontal A-panel grating heterogeneous and axially heterogeneous-C-panel grating, wherein makes these gratings so that its (to small part) overlaps (promptly accounting for same position in the space).Although A-panel grating and-thin layer of C-panel grating is considered to according to the relevant coupling of optical interference, still the lag characteristic of each A-panel grating section and-C-panel grating section is different and its characteristic is described by its oneself refractive index curve model.Although this point provides the different choice of these two sections of structure on one or two surface of transparency carrier, and simplified manufacturing process, but for high-performance modulation delayer was used, birefringence was always best in the significant surface of the A-panel grating that is produced.For example, referring to K.Tan et al., " Design and characterization of a compensator forhigh contrast LCoS projection systems ", SID 2005, p.1810,2005.In addition, if coated technique can't carry out real conformal deposit, conventional thin film sputtering technology can produce hole under coating deposited.The coating material flux (flux) of photographic fixing and shortage certain angle scope is the main cause that forms top cover (roof) structure hole.

[218] for avoiding these problems; replacedly design the texture surface grating so that coated technique is filled linear grating groove fully to guarantee the exposure reliability of environment and luminous flux; and make the A-panel produced postpone to be distributed in thicker birefringent film to fasten, thereby produce the low-birefringence delayer that comprises that equally an amount of negative C-panel postpones.More specifically, suggestion adopts the coated technique of more effectively filling these grooves to make A-panel grating, simultaneously, duplicates initial optical grating construction basically so that A-panel optical grating construction extends into C-panel optical grating construction.

[219] front has proposed grating replication, and wherein the RF bias sputtering is used for thickness " automatically cloning " master grating by deposited film.Particularly, proposed to duplicate stable horizontal raster pattern by each continuous right coated material by between RF sputtering sedimentation and RF ise, selecting suitable balance.For example, referring to S.Kawakami et al., " Mechanism of shape formation of three dimensional peroidic nanostructures by biassputtering ", Appl.Phys.Lett., 74 (3), pp.463-465,1999 and/or and T.Sato et al., " Photoniccrystals for the visible range fabricated by autocloning technique and their applications ", Opt.Quant.Elect., 34 pp.63-70,2002, confirmed that wherein light delay device can be by duplicating the surface preparation of the periodic patterns with little side direction pitch (and cycle) to 180nm automatically.The layer of deposition is constructed to high reflective mirror, and this high reflective mirror has the center and is being longer than predetermined first order reflection of using the wavelength place of wavelength window.According to back one piece of document, an automatic replica delay device has the thickness of 167nm for every pair of monox/tantalum oxide layers.Repeat this cycle 10 times A-panel delay (or delay of 174nm) with about 0.87 π of obtaining at λ=400nm place.The termination zone center is at about λ=600nm, and the delayer intention is used in λ=400nm place.

[220] there are several problems in these grating retarder arrangement that the LCoS compensator is used.By using the wavelength region may between first order reflection and the more senior secondary reflection, obtain positive face external delays compensation.In addition, birefringence is used and Yan Taida for low reflection compensation device in the significant surface of this design.In delay place of～174nm, effectively Δ n is about 0.1, and each effective Δ n realizes with the 167nm in about 10 cycles.Obviously, for for the application of UV/ visible waveband, whether automatically these documents do not have open clone method that the transversely zero level grating on plane and device normal can be provided.

[221] substrate/(LH) the high reflective mirror design conduct of ^10/ atmosphere can be by an example of the firm and hard existing delay that is coated with dielectric film, wherein L is the low-index material such as monox, H is the high-index material such as tantalum oxide, and the two is all enough transparent on the visible wavelength band.It (that is is at λ, that the size of these layers is designed in central wavelength ₀The quarter-wave at=300nm place) produces the quarter-wave optical thickness.L that is produced and H thickness are about 50nm and 30nm respectively.50nm monox and right transmissivity that calculates and the transmission of 30nm tantalum oxide that Figure 38 is illustrated in the 10 pairs of repetitions in 45 ° of incident angle places postpone.First order reflecrtive mark is 395.At the wavelength place of being longer than first order reflected waveband 396, obtain high transmission throughput and negative transmission delay.If the delay that stands at the non-normal incidence P of place polarized light is greater than the S polarized light, the symbol of delay is being for just, and if the delay that stands at the non-normal incidence P of place polarized light less than the S polarized light, the symbol of delay is for negative.For being shorter than first order reflection but be longer than the next more wavelength of senior reflection 397, delay is positive.The panel that should be noted that this dielectric coated only produces+delay of C/-C-panel.For normal incident light, the clean delay is zero.More particular contents of the C-panel delay that is coated with film are disclosed in the US temporary patent application 60/803,735 that is to submit on June 2nd, 2006.

[222] in order to reduce interference effect, axially grating should be configured to the zero level grating, and paired high/low index layer should be thinner than the operation wavelength of expectation far away.In this case, provide negative face external delays.Use this film coating by going up, obtain birefringence in the bottom surface equally at " mother " grating (that is, the initial surface releasing structure).More specifically, be distributed in unmodulated coating dielectric layer that coated film fastens and provide in the face and postpone by a series of.

[223] Figure 39 and 40 illustrates initial etching, some examples of " mother " grating of pre-coated.With reference to Figure 39, master grating 1400 comprises non-reticulate pattern substrate 1490, be deposited on the etch stop layer 1421 on this non-reticulate pattern substrate 1490 and be deposited on dielectric on the etch stop layer 1421.For example adopt photoetching and etching or stripping technology with this dielectric patternization to form binary raster 1420, this binary raster comprises a plurality of first grating stylobates 1430 with first width 1431 that are arranged alternately with the second grating groove 1440 with second width 1441.Preferably, this first and second width is a sub-wavelength dimensions.The height of this A-panel grating 1420 is 1427, is suitable for continuous electric medium coating deposition.The dielectric substance of making grating stylobate 1430 is different with the material of grating substrate 1490.

[224], the another kind of method that realizes master grating 1405 is shown with reference to Figure 40.Master grating 1405 directly is etched into substrate 1495, has or do not have the photoresist of peeling off pattern.Master grating comprises binary raster element 1425, and this binary raster comprises a plurality of first grating stylobates 1435 with first width 1436 that the second grating groove 1445 with second width 1446 is arranged alternately.The height of this A-panel grating 1425 is 1427, is suitable for continuous electric medium coating deposition.The dielectric substance of making grating stylobate 1435 is identical with the material of grating substrate 1495.

[225], obtain form birefringent A-panel by the periodicity sub-wavelength binary modulation on master grating according to zero level EMT formula (1).The dutycycle of this grating is provided by formula (3).As an example, the grating that has refractive index and be an air channels of 1.46 stylobate and 50: 50 space ratios provides birefringence in 0.0846 the significant surface:

${\mathrm{<figure-callout\; id="0"\; label="n\; o"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}_o^{}=1.2513,$ $n_e^0=1.1680,$ $\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}^0=n_e^0-{\mathrm{<figure-callout\; id="0"\; label="n\; o"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}_o^{}=-0.0846---\left(5\right)$

[226] as shown in Figure 5, effectively the mono-axial refractive index curve is discoid, has negative birefringence.For the extremely thin grating layer that highly is h, h＜＜λ, wherein λ is an operation wavelength, secondary EMT in zero level EMT in the formula (1) and the formula (2) can't calculate to a nicety effective refractive index and effectively birefringence, this zero level and secondary EMT comprise the additional parameter such as grating space p and operation wavelength λ.(for example can reckon with other secondary EMT formula, referring to C.W.Haggans et al., " Effective-medium theory of zeroth order lamellar gratings inconical mountings ", J.Opt.Soc.Am.A, 10, pp.2217-2225,1993) also be coarse for extremely thin grating.For the effective refractive index and the birefringence of the one dimension binary raster of evaluation rule, adopt RCWA model (Grating Solver Development Company, Allen, Texas, version 4.20b).Binary raster is configured to the glass raster (being similar to device 1405) of etching.Selected baseplate material is Xiao Te float glass process Pyrex (Schott Borofloat).Be starkly lower than with birefringence in the significant surface of float glass process borosilicate (Borofloat) glass of 150nm and 200nm grating cycle, 50% dutycycle etching (in the nano level transmission plane in normal incidence place, postponing ratio) and adopt birefringence in the significant surface that zero level and secondary EMT formula estimate with the physical height of nano level individual layer grating.These GSolver analog results are shown in Figure 41, λ=550nm.The grating height is displaced to 500nm from 10nm, is step-length (step) with 10nm.Birefringence illustrates the attenuation steps function along with the vibration growth that produces at big highly place owing to interference effect in the significant surface after this typing.At selected grating height place, the optical thickness of ordinary wave less than quarter-wave (that is, $h<\mathrm{\&lambda;}/4/n_o^0,$ In this simulative example corresponding to the physical height of 110nm), according to the EMT formula attainable comprehensively in birefringence be reduced.In fact, can be applicable in the horizontal binary raster in order to make the EMT formula, grid line must be quite thick.The sheet of simulation stacked series of parallel in vertical plane, its width and length are much larger than operation wavelength.Should " book is piled up (book-stack) " model shown in Figure 42.Optical device 1460 has periodic first medium " thin slice " 1461 in the middle of second medium 1462 that is layered on the substrate 1469.Do not lose ubiquity ground, can not think and carry out apart from 1465 with fixed knot along X-axis that this is stacked.Each " wave plate " all has wavelength width 1466 and the height 1467 in use.But even for normal incident light, for the way of realization birefringence, raster pitch 1465 is much smaller than this wavelength (that is interior the or A-panel delay of generation face).

[227] in fact, book is piled up model and improper.The horizontal expansion of optical element is generally much larger than illumination wavelengths.Because the use of form birefringent zero level grating, grid line far is narrower than optical wavelength.The height dimension of grid line is the parameter of interference of light design.This parameter is generally less than illumination wavelengths or can compares with illumination wavelengths.Satisfy at the grating height under the situation of its height condition, birefringence is cancelled in the attainable significant surface.Grating can think to immerse the many small sheet of first material in second material medium.This point shown in Figure 43.For given volume, device 1470 comprises many first material block 1471, and their longitudinal axis is parallel to Y-axis and is oriented on a very long segment distance.Remaining volume is filled by second material 1472.The order that is installed in first and second materials on the substrate 1479 along XZ cross-sectional view arbitrarily might not generation rule grating stylobate/groove structure.This material volume has height 1473, and this highly is shorter than optical wavelength and can compares with optical wavelength.On the contrary, this volume is infinite along Y-axis 1474 with along the horizontal expansion of X-axis 1475 with respect to optical wavelength.First and second materials are dielectrics and do not possess polarizability.The distribution simulation of first and second materials is the birefringence liquid crystal molecule (distribution with positive single shaft LC of tension shape) in host's potpourri.According to law of averages, first dielectric volume fraction is f ₁Second dielectric volume fraction is f ₂The 3rd dielectric volume fraction is f ₃Deng.According to these volume fractions of having determined, illustrate three-dimensional (3D) the refractive index mixture model (IMM) of single grating layer.Mix for two or more materials, zero level EMT formula is employed to produce effective refractive index and birefringent first estimation:

${\mathrm{<figure-callout\; id="0"\; label="n\; o"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}_o^{}=\sqrt{f_1{\left(n_1\right)}^2+f_2{\left(n_2\right)}^2+...f_i{\left(n_i\right)}^2+...f_N{\left(n_N\right)}^2}---\left(6\right)$

$n_e^0=1/\sqrt{f_1{\left(n_1\right)}^2+f_2{\left(n_2\right)}^2+...f_i{\left(n_i\right)}^2+...f_N{\left(n_N\right)}^2}---\left(7\right)$

$\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}^0=n_e^0-n_o^0---\left(8\right)$

Wherein, in the N material unit of the being blended in grating volume; The component material refractive index n ₁To n _NBe that wavelength is relevant; Δ n ⁰Be zero level EMT birefringence (ZOB), this value is generally negative.

[228] in order when the individual layer grating far is thinner than optical wavelength, to embody the birefringence effect that reduces, plug-type model has been proposed." pushing away " function comes comfortable grating height near optical wavelength or the birefringent exponential increase of full zero level when thicker; " draw " function from the exponential damping item, it has reduced ZOB when infinite at raster pitch on assigned direction.Along the unit bodies grid (X, Y, Z) effective refractive index of these on the direction (nx, ny, nz) be shown as follows:

$n_x={\mathrm{<figure-callout\; id="0"\; label="n\; o"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}_o^{}+\exp (-\mathrm{\&alpha;}{p}_x/\mathrm{\&lambda;})\&times;[1-\exp (-\mathrm{\&delta;h}/\mathrm{\&lambda;})\&times;(n_e^0-n_o^0)]---\left(9\right)$

$n_y={\mathrm{<figure-callout\; id="0"\; label="n\; o"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}_o^{}+\exp (-\mathrm{\&beta;}{p}_y/\mathrm{\&lambda;})\&times;[1+\exp (-\mathrm{\&delta;h}/\mathrm{\&lambda;})\&times;(n_e^0-n_o^0)]---\left(10\right)$

$n_z={\mathrm{<figure-callout\; id="0"\; label="n\; o"\; filenames="A20061013809300791.png,A20061013809300811.png"\; state="\{\{state\}\}">n</figure-callout>}}_o^{}+\exp (-\mathrm{\&gamma;}{p}_z/\mathrm{\&lambda;})\&times;[1-\exp (-\mathrm{\&delta;h}/\mathrm{\&lambda;})\&times;(n_e^0-n_o^0)]---\left(11\right)$

Wherein (α, beta, gamma) be respectively along (X, Y, Z) the ZOB attenuation coefficient of direction, it is determined by data fitting; (p _x, p _y, p _z) in unit bodies grid (X, Y, Z) pitch on the direction; H is the grating height; δ is the ZOB growth factor; λ is an optical wavelength.Birefringence is illustrated as initial GSolver data in Figure 41 in the face of the match at λ=550nm place.For 150nm and 200nm Borofloat/ air grille, (α, beta, gamma δ) are [0.17,0.1,0.1,12.0] to fitting coefficient.

[229] second aspect that adopts the EMT formula to describe the main error of A-panel grating is the face external delays.Usually hypothesis grating positive dirction has ordinary refractive index.Therefore, one of the equivalent model of binary raster negative mono-axial refractive index curve that to be its e ripple axle point to along grating vector (for example, X-axis).This is approximate true for thick grating.For the glimmer grid, the equivalent single layer birefringence model is more near the refractive index curve figure shown in Figure 44.Effective twin shaft refractive index curve of the thin binary raster of birefringent layers 1450 expressions.Grating height and equivalent model thickness h are by 1451 expressions.Three main refractive index (n _x, n _y, n _z) respectively by 1452,1453 and 1454 expressions.Replace the n in the thick binary raster _y=n _z=n _oAnd n _x=n _e, more accurate IMM model provides n _y＞n _xAnd n _z≈ n _xBy curve fitting intensity in transmission and reflection strength and postpone to distribute incident angle is determined positive single shaft refractive index curve a little less than this.By n is set _a＜n _b＜n _cThis equivalence birefringent layers is classified as weak twin shaft medium, wherein (n _a, n _b, n _c) be the material coordinate system (when representing with laboratory coordinate system with (n _x, n _y, n _z) relatively) and in main refractive index.

[230] example of data fitting shown in Figure 45 (a) to (d).The Borofloat glass/air grid that 40nm is high simulated in GSolver.Its compound field output to a series of polar angles and observed azimuth is output to the data fitting program.Set up IMM so that the equivalent single layer birefringent medium produces identical intensity and postpones angular spectrum in transmission and reflection.At the data fitting wavelength place of 550nm, IMM provides:

[n _x，n _y，n _z]＝[1.1803，1.2338，1.1960] (12)

[231] with reference to Figure 45 (a), it is illustrated in the transmission spectrum of the 40nm Borofloat glass/air glimmer grid of the match on the Borofloat substrate.Triangular marker is corresponding to fitting data, and dotted line is exported corresponding to the GSolver compound field.φ _vThree azimuthal plane of=0,45 and 90 ° are by match.Tpp (the p polarization is gone into, and the p polarization goes out) transmission becomes big along with the AOI on whole incident orientation plane and is tending towards rising, and Tss (the s polarization is gone into, and the s polarization goes out) becomes big along with the AOI on whole incident orientation plane and is tending towards descending.With reference to Figure 45 (b), it is illustrated in the reflectance spectrum of the 40nm Borofloat glass/air glimmer grid of the match on the Borofloat substrate.Circular mark is corresponding to fitting data, and dotted line is exported corresponding to the GSolver compound field.φ _vThree azimuthal plane of=0,45 and 90 ° are by match.Rpp (the p polarization is gone into, and the p polarization goes out) transmission becomes big along with the AOI on whole incident orientation plane and is tending towards descending, and Rss (the s polarization is gone into, and the s polarization goes out) becomes big along with the AOI on whole incident orientation plane and is tending towards rising.With reference to Figure 45 (c), its radiotransparency that is illustrated in the 40nm Borofloat glass/air glimmer grid of the match on the Borofloat substrate postpones, and the reflection linear delay of the 40nm Borofloat glass/air glimmer grid of the match on the Borofloat substrate shown in Figure 45 (d).Obviously, the delay on transmission and reflection direction distributes and departs from GSolver 0.2nm as a result at most.To the intensity error of reflection less than to the intensity error of transmission (in this grating example up to 1% error).

[232] these simulations show that the main refractive index result of the match in (12) is more accurate than the prediction of the EMT in (5) for intensity difference and phase differential (promptly postponing) quantity.In other words, the main refractive index of match is more near the interference pattern of glimmer grid.The EMT of example grating and the angle of IMM model are postponed to be distributed in to provide contrast among Figure 46.More specifically, for 40nm Borofloat, provided and adopted air grating that EMT result and new IMM equivalent layer calculate and by the radiotransparency that the target data that GSolver produces is compared postpone the to distribute result of relative incident angle.EMT not only dopes birefringence n α in the wrong face, and the outer birefringence nc of face obviously also is wrong.The birefringence element of these quadratures is defined as:

Δ n _α=n _y-n _xAnd Δ n _c=n _z-(n _y+ n _x)/2 (13)

[233] obvious, the EMT model provides Δ n _cAs ZOB (the Δ n of half _c=Δ n ⁰).But the IMM model prediction does not almost have the outer birefringence of face.The spectrum of these birefringence elements of the wave band of 400nm-700nm shown in Figure 47 (EMT and IMM model).The glimmer grid preferably are fixed to weak twin shaft layer (with IMM) rather than negative single shaft layer (with EMT).As shown in figure 46, the EMT model provides the function of the bigger variation of clean delay as incident angle.

[234] in given X-ray grid (i.e. the grating vector that points to along X-axis) example, birefringence increases along with the increase of grating height on the axle, wherein n _xReduce n _yAnd n _zIncrease.The indicatrix of individual layer grating is described from positive twin shaft media variations to negative twin shaft medium, and finally by locating to adopt the negative single shaft medium of EMT model fully to represent at big grating height (greater than the quarter-wave optical thickness of employing zero level EMT ordinary refractive index).Under the situation of big grating height, it is enough and n that book is piled up model _x=n _y, be better than having on long range direction and n at little grating height _z≈ n _xThe excellent at random model of 3D.Represent the glimmer grid with more accurate birefringence IMM model, the interchangeable embodiment of the present invention obtains describing and simulation (promptly as film system).

[235], global function A/-C-panel grating trim retarders according to another embodiment of the present invention is shown with reference to Figure 48.This global function A/-C-panel grating trim retarders 1500 comprise the first film on the first surface that is positioned at transparency carrier 1590 be 1505 and second film that is positioned on the second surface of transparency carrier 1590 be 1595.The first film is 1505 the 3rd interludes 1562 that comprise with axial periodic refractive index modulator element 1560 heterogeneous first section, comprise second section of horizontal periodic refractive index modulator element 1522 heterogeneous and axially non-homogeneous and horizontal periodic refractive index modulator element heterogeneous are provided.Usually, postpone in first section 1560 display surface external delays, second section 1522 display surface, interlude 1562 is simultaneously in the display surface and the face external delays.First film is 1505 to comprise that also it is 1521 and outside surface AR layer 1561 that optional etching stops film.The outside surface AR layer 1561 and second film are 1595 all to provide anti-reflection function, and the outside surface AR layer 1561 and second film are 1595 generally to be the dielectric thin layer.

[236] generally forming the first film by deposition form birefringent antireflection (FBAR) film system on master grating is 1505.Master grating 1522 comprises a plurality of stylobates that are arranged alternately with a plurality of grooves (being illustrated as being filled with part FBAR film system), and this master grating 1522 is horizontal periodic refractive index modulator elements heterogeneous.Preferably, select the width of these stylobates and groove so that this master grating and/or FBAR wavy (undulating) section forms the horizontal zero level sub-wave length grating that form birefringent in the face is provided.Generally by being the master grating 1522 of net grain surface in essence from being positioned at etch stop layer 1521 etchings on the glass substrate 1590 or peeling off the top dielectric preparation.Replacedly, adopt another kind of technology to prepare patterned surface, space.For example, this master grating replacedly be prepared as patterning on etch substrate (for example shown in Figure 40), the transparency carrier the photoresist layer, comprise dielectric 1/ dielectric 2 patterns of physical step etc.For the application in the 380nm-800nm wave band, master grating 1522 generally has the raster pitch less than about 250nm, the dutycycle that changes, the height of the modulation between the 5nm-200nm in 5%-95% (more preferably at 20%-80%) scope.Some examples that are applicable to the material of master grating comprise organic dielectric and inorganic dielectric, and this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), for example MgF ₂Fluoride, sulfide, silicon nitride etc.Except shown in binary (rectangle) master grating pattern, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine, and/or the trapezoidal grating pattern.In fact, any patterned layer that plays the sedimentary deposit effect of disturbing continuously coating all can be used as master grating.

[237] comprising first section 1560 with the FBAR film of interlude 1562 is 1550 to be illustrated as being formed by two kinds of different materials.As shown in Figure 48, first section 1560 is axially heterogeneous, periodic refractive index modulator elements, and this first section 1560 comprises first multilayer 1570, and every layer all has first refractive index and the first thickness 1571d ₁, being arranged alternately with second multilayer 1580, every layer of this second multilayer 1580 all has second refractive index and the second thickness 1581d ₂Select in first multilayer and second multilayer every layer material and bed thickness, provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two-layer different layer material, can adopt more than two kinds of different layer materials.The material that is fit to of first and/or second multilayer comprises organic and inorganic dielectric matter.

[238] interlude 1562 that comprises axially non-homogeneous and horizontal non-homogeneous periodic refractive index modulation areas easily by with first section 1560 in the same material of employing make.In this case, generally deposition first section 1560 and interlude 1562 in same process for example, adopts conventional vacuum deposition process to deposit.Usually, deposition interlude 1562 is so that first pair of thin layer to the small part meets the shape of master grating and periodic undulations (undulation) along the plane of substrate 1590 is provided.The alternately index distribution (that is, at xsect with vertically on all provide periodic refractive index modulate) of device X-Y plane at a plurality of lengthwise positions place is provided in these 1510 generations that rise and fall.Therefore, form A-panel light grid element (little ridge (gratlet)) in X-Y cross-section with horizontal periodic refractive index modulation heterogeneous.Each little ridge all comprises more than first individual regional, and each of these more than first zones all have first width and first refractive index, and with more than second regional replacing, each of these more than second zones all have second width and second refractive index.The thickness of each little ridge and dutycycle all change (for example, surpassing 99% from changing into less than 1%) continuously.This fluctuating produces in the sensitive surface in coating and postpones.In fact, the initial net grain surface 1522 and the coating 1510 of wavy (undulating) are to postpone to work in 1505 the face to total film all.Obviously, postpone generally to postpone in the face greater than initial master grating in the face by coating design and/or coated technique introducing.Expediently, film is that 1505 material and bed thickness generally make interlude 1562 also can play the effect of inner refractive index match block.

[239] although only described wavy (undulating) layer according to interlude 1562, in fact, the border between the wavy and non-undulating horizon may not be clearly.In fact, whole in many cases film 1550 will be risen and fallen, outermost layer have minimum relief intensity (along the Wave crest and wave trough difference in height of coating surface＜＜1nm).Under any circumstance, postpone in the face to provide by Distribution Effect.More specifically, it is neighbouring maximum that delay is distributed in female layer in the face, and reduce gradually towards the direction of outermost coating.This distribution also is discontinuous, because a plurality of parts (fraction) that there is coating thickness in material variations in refractive index part in the transverse plane do not occurring.

[240] obvious, this global function A/-C-panel is adjusted delayer and is come down to the three-D volumes holographic element, and it has the horizontal modulation period constant with respect to thickness, and has the fluctuating range of warbling along film thickness direction.

[241] advantageously, provide and postpone in the face of delay and this global function A/-C-panel of negative face external delays is adjusted delayer and easily is manufactured to full dielectric and adjusts delayer with definition axle.In addition, postpone in the tru(e)ing face easily according to demands of applications (for example, special LCoS family device) and the amplitude of face external delays.In addition, the AR characteristic also is optimized to make the be not adjusted restriction of undesirable cross polarization reflection of delayer of compensation panel contrast.The Distribution Effect of the A-panel delay element in the coating has guaranteed low-birefringence (it helps to produce low cross polarization reflection) and has increased the band coating grating pair that the A-panel that does not have the coating grating postpones.The part conformal spreading that for example is provided with in the vacuum deposition chamber of routine guarantees not exist the cap structure hole.As a result, for using in the optical projection system based on polarization, it is desirable that this global function A/-C-panel is adjusted delayer.

[242], global function A/-C-panel grating trim retarders according to another embodiment of the present invention is shown with reference to Figure 49.This global function A/-C-panel grating trim retarders 1600 comprise the first film on the first surface that is positioned at transparency carrier 1690 be 1605 and second film that is positioned on the second surface of transparency carrier 1690 be 1655.

[243] the first film is 1605 the 3rd interludes 1662 that comprise with axial periodic refractive index modulator element 1660 heterogeneous first section, comprise second section of horizontal periodic refractive index modulator element 1622 heterogeneous and axially non-homogeneous and horizontal periodic refractive index modulator element heterogeneous are provided.Usually, postpone in first section 1660 display surface external delays, second section 1622 display surface, interlude 1662 is simultaneously in the display surface and the face external delays.First film is 1605 to comprise that also it is 1621 and outside surface AR layer 1661 that optional etching stops film.

[244] forming the first film by deposition form birefringent antireflection (FBAR) film system on master grating is 1605.Master grating 1622 is shown as including a plurality of stylobates that are arranged alternately with a plurality of grooves (being illustrated as being filled with part FBAR film system), and this master grating 1622 is horizontal periodic refractive index modulator elements heterogeneous.Preferably, select the width of these stylobates and groove so that the wavy section formation of this master grating and/or FBAR provides the horizontal zero level sub-wave length grating of form birefringent in the face.Generally by being the master grating 1622 of net grain surface in essence from being positioned at etch stop layer 1621 etchings on the transparency carrier 1690 or peeling off the top dielectric preparation.Replacedly, adopt another kind of technology to prepare patterned surface, space.For example, this master grating replacedly is prepared as patterned photoresist layer on etch substrate (for example shown in Figure 40), the transparency carrier, comprises dielectric 1/ dielectric 2 patterns of physical step etc.For the application in the 380nm-800nm wave band, master grating 1622 generally has the raster pitch less than about 250nm, the dutycycle that changes, the height of the modulation between the 5nm-200nm in 5%-95% (more preferably at 20%-80%) scope.Some examples that are applicable to the material of master grating comprise organic dielectric and inorganic dielectric, and this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), for example MgF ₂Fluoride, sulfide, silicon nitride etc.Except shown in binary (rectangle) master grating pattern, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine and/or trapezoidal grating pattern.In fact, any patterned layer that plays the sedimentary deposit effect of disturbing continuously coating all can be used as master grating.

[245] comprising first section 1660 with the FBAR film of interlude 1662 is 1650 to be shown by two kinds of different materials and to form.As shown in Figure 49, first section 1660 is axially heterogeneous, periodic refractive index modulator elements, and this first section 1660 comprises first multilayer 1670, and every layer all has first refractive index and the first thickness 1671d ₁, being arranged alternately with second multilayer 1680, every layer of this second multilayer 1680 all has second refractive index and the second thickness 1681d ₂Select in first multilayer and second multilayer every layer material and bed thickness, provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two-layer different layer material, can adopt more than two kinds of different layer materials.The material that is fit to of first and/or second multilayer comprises organic and inorganic dielectric matter.

[246] interlude 1662 that comprises axially non-homogeneous and horizontal non-homogeneous periodic refractive index modulation areas easily by with first section 1660 in the same material of employing make.In this case, generally deposition first section 1660 and interlude 1662 in same process for example, adopts conventional vacuum deposition process to deposit.Usually, deposition interlude 1662 is so that first pair of thin layer to the small part meets the shape of master grating and provide along the periodic undulations on the plane of substrate 1690.The alternately index distribution (that is, at xsect with vertically on all provide periodic refractive index modulate) of device X-Y plane at a plurality of lengthwise positions place is provided in these 1610 generations that rise and fall.Therefore, form the little ridge of A-panel in X-Y cross-section with horizontal periodic refractive index modulation heterogeneous.Each little ridge all comprises more than first individual regional, and each of these more than first zones all have first width and first refractive index, and with more than second regional replacing, each of these more than second zones all have second width and second refractive index.The thickness of each little ridge and dutycycle all change (for example, surpassing 99% from changing into less than 1%) continuously.This fluctuating produces in the sensitive surface in coating and postpones.In fact, initial net grain surface 1622 and wavy coating 1610 are to postpone to work in 1605 the face to total film all.Obviously, postpone generally to postpone in the face greater than initial master grating in the face by coating design and/or coated technique introducing.Expediently, film is that 1605 material and bed thickness generally make interlude 1662 also can play the effect of inner refractive index match block.

[247] although only described undulating horizon according to interlude 1662, in fact, the border between the wavy and non-undulating horizon may not be clearly.In fact, whole in many cases film 1650 will be risen and fallen, outermost layer have minimum relief intensity (along the Wave crest and wave trough difference in height of coating surface＜＜1nm).Under any circumstance, postpone in the face to provide by Distribution Effect.More specifically, it is neighbouring maximum that delay is distributed in female layer in the face, and reduce gradually towards outermost coating direction.This distribution also is discontinuous, because a plurality of parts that there is coating thickness in material variations in refractive index part in the transverse plane do not occurring.

[248] be that 1655 formation, second film is 1655 by the deposition second form birefringent AR film on the non-net grain surface of transparency carrier 1690.The 2nd FBAR comprises that the refractive index alternate films that generally comprises two or more materials is 1665, the external refractive index match block 1667 and inner refractive index match block 1668.Axial cyclic structure 1665 comprises first multilayer 1675, and every layer all has first refractive index and first thickness, is arranged alternately with second multilayer 1685, and every layer of this second multilayer all has second refractive index and second thickness.This FBAR element 1655 shows at the normal incidence place not to be had to postpone in the face.From axle incident place, e wave refraction rate is less than o wave refraction rate.This FBAR element 1655 shows negative face external delays.The external refractive index match block 1667 and inner refractive index match block 1668 all provide anti-reflection function, and these two match block generally all are the dielectric thin layers.

[249] obvious, this global function A/-C-panel is adjusted delayer and is come down to the three-D volumes holographic element, and it has the horizontal modulation period constant with respect to thickness, and has the fluctuating range of warbling along film thickness direction.

[250] preferably, provide and postpone in the face of delay and this global function A/-C-panel of negative face external delays is adjusted delayer and easily is manufactured to full dielectric and adjusts delayer with definition axle.In addition, postpone in the tru(e)ing face easily according to demands of applications (for example, special LCoS family device) and the amplitude of face external delays.In addition, the AR characteristic also is optimized to make the be not adjusted restriction of undesirable cross polarization reflection of delayer of compensation panel contrast.The Distribution Effect of the A-panel delay element in the coating has guaranteed low-birefringence (it helps to produce low cross polarization reflection) and has increased the band coating grating pair that the A-panel that does not have the coating grating postpones.The part conformal spreading that for example is provided with in the vacuum deposition chamber of routine guarantees not exist the cap structure hole.As a result, to adjust the optical projection system that delayer is used for based on polarization be desirable to this global function A/-C-panel.

[251] film design comprises that equivalent birefringence model is to show the thin grating layer of every layer of alternative materials in transverse plane.Provide simulation and the example total reflectance of measuring of the grating of band coating among Figure 50.The master grating that is used for result shown in Figure 50 has the grating degree of depth of about 40nm.The grating of second band coating has with respect to the delay distribution along the slow axis plane shown in Figure 51 and the incident angle of fast axial plane.In this case, with reference to negative uniaxial material refractive index { n in λ=550nm place standard _e=1.50, n _o=1.65}, C panel postpone to be fitted to pact-200nm.Some have the initial master grating height between 25-50nm and have various FBAR and repeat the transmission delay spectrum that measures to the band coating grating of thickness shown in Figure 52 (a).Depend on master grating and coated designs, the nominal radiotransparency at λ=550nm place postpones to change between 8nm-12nm.For relatively, be in the no coating grating of measurement between 1nm and the delay of 3nm radiotransparency at λ=550nm shown in Figure 52 (b).It is the result of distributed fluctuating in the coating that extra induction postpones.Wish to design in the face that has in the visible waveband scope and postpone up to tens nanometers, and tens delayers by a small margin that postpone to the negative C-panel of hundreds of.The light delay device of the band coating of the distributed grating of this employing has significantly improved the consecutive image contrast of LCoS photo engine.As an example, provided the relative closed condition contrast of the open mode with the VAN model LCoS photo engine that postpones in the nominal 2nm face among Figure 53.Conical illumination is arranged on f/2.5.Under this circular cone, all rays all are compensated after passing based on the adjustment delayer of full dielectric grating and Reflector Panel fully.Uncompensated panel contrast is about 2,000: 1, and provide nearly 7,000 based on the panel after the delayer compensation of grating: 1 continuous contrast.On visible waveband, these contrasts are fitted the light weighting.The contrast of wave band one by one shown in Figure 53.

[252], global function A/-C-panel grating trim retarders according to another embodiment of the present invention is shown with reference to Figure 54.This global function A/-C-panel grating trim retarders 1700 comprise the first film on the first surface that is positioned at transparency carrier 1790 be 1705 and second film that is positioned on the second surface of transparency carrier 1790 be 1755.

[253] the first film film is 1705 the 3rd interludes 1762 that comprise with axial periodic refractive index modulator element 1760 heterogeneous first section, comprise second section of horizontal periodic refractive index modulator element 1722 heterogeneous and axially non-homogeneous and horizontal periodic refractive index modulator element heterogeneous are provided.Usually, postpone in first section 1760 display surface external delays, second section 1722 display surface, interlude 1762 is simultaneously in the display surface and the face external delays.First film is 1705 to comprise that also it is 1721 and outside surface AR layer 1761 that optional etching stops film.

[254] forming the first film film by deposition form birefringent antireflection (FBAR) film system on master grating is 1705.Master grating 1722 is shown as including a plurality of stylobates that are arranged alternately with a plurality of grooves (being illustrated as being filled with part FBAR film system), and this master grating 1722 is horizontal periodic refractive index modulator elements heterogeneous.Preferably, select the width of these stylobates and groove so that the wavy section formation of this master grating and/or FBAR provides the horizontal zero level sub-wave length grating of form birefringent in the face.Generally by being the master grating 1722 of net grain surface in essence from being positioned at etch stop layer 1721 etchings on the transparency carrier 1790 or peeling off the top dielectric preparation.Replacedly, adopt another kind of technology to prepare patterned surface, space.For example, this master grating replacedly is prepared as patterned photoresist layer on etch substrate (for example shown in Figure 40), the transparency carrier, comprises dielectric 1/ dielectric 2 patterns of physical step etc.For the application in the 380nm-800nm wave band, master grating 1722 generally has the raster pitch less than about 250nm, the dutycycle that changes, the height of the modulation between the 5nm-200nm in 5%-95% (more preferably at 20%-80%) scope.Some examples that are applicable to the material of master grating comprise organic dielectric and inorganic dielectric, and this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), for example MgF ₂Fluoride, sulfide, silicon nitride etc.Except shown in binary (rectangle) master grating pattern, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, apart from string and/or trapezoidal grating pattern.In fact, any patterned layer that plays the sedimentary deposit effect of disturbing continuously coating all can be used as master grating.

[255] comprising first section 1760 with the FBAR film of interlude 1762 is to be shown by two kinds of different materials to form.As shown in Figure 54, first section 1760 is axially heterogeneous, periodic refractive index modulator elements, this first section 1760 comprises first multilayer 1770, every layer all has first refractive index and first thickness, be arranged alternately with second multilayer 1780, every layer of this second multilayer 1780 all has second refractive index and second thickness.Select in first multilayer and second multilayer every layer material and bed thickness, provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two-layer different layer material, can adopt more than two kinds of different layer materials.The material that is fit to of first and/or second multilayer comprises organic and inorganic dielectric matter.

[256] interlude 1762 that comprises axially non-homogeneous and horizontal non-homogeneous periodic refractive index modulation areas easily by with first section 1760 in the same material of employing make.In this case, generally deposition first section 1760 and interlude 1762 in same process for example, adopts conventional vacuum deposition process to deposit.Usually, deposition interlude 1762 is so that first pair of thin layer to the small part meets the shape of master grating and provide along the periodic undulations on the plane of substrate 1790.The alternately index distribution (that is, at xsect with vertically on all provide periodic refractive index modulate) of device X-Y plane at a plurality of lengthwise positions place is provided in these 1710 generations that rise and fall.Therefore, form the little ridge of A-panel in X-Y cross-section with horizontal periodic refractive index modulation heterogeneous.Each little ridge all comprises more than first individual regional, and each of these more than first zones all have first width and first refractive index, and with more than second regional replacing, each of these more than second zones all have second width and second refractive index.The thickness of each little ridge and dutycycle all change (for example, surpassing 99% from changing into less than 1%) continuously.This fluctuating produces in the sensitive surface in coating and postpones.In fact, initial net grain surface 1722 and wavy coating 1710 are to postpone to work in 1705 the face to total film all.Obviously, postpone generally to postpone in the face greater than initial master grating in the face by coating design and/or coated technique introducing.Expediently, film is that 1705 material and bed thickness generally make interlude 1762 also can play the effect of inner refractive index match block.

[257] second film are 1755 to comprise with axial periodic refractive index modulator element 1765 heterogeneous first section, the 3rd interlude 1767 that comprises second section of horizontal periodic refractive index modulator element 1727 heterogeneous and axial and horizontal periodic modulation heterogeneous zone is provided.Usually, postpone in first section 1765 display surface external delays, second section 1727 display surface, interlude 1767 is simultaneously in the display surface and the face external delays.Second membrane system 1755 comprises that also it is 1726 and outside surface AR layer 1766 that optional etching stops film.

[258] forming second film by deposition form birefringent antireflection (FBAR) film system on second master grating is 1755.Second master grating 1727 is shown as including a plurality of stylobates that are arranged alternately with a plurality of grooves (being illustrated as being filled with part FBAR film system), and this master grating 1727 is horizontal periodic refractive index modulator elements heterogeneous.Preferably, select the width of these stylobates and groove so that the wavy section formation of this master grating and/or FBAR provides the horizontal zero level sub-wave length grating of form birefringent in the face.Generally by being the master grating 1727 of net grain surface in essence from being positioned at etch stop layer 1726 etchings on the transparency carrier 1790 or peeling off the top dielectric preparation.Replacedly, adopt another kind of technology to prepare patterned surface, space.For example, this master grating replacedly is prepared as patterned photoresist layer on etch substrate (for example shown in Figure 40), the transparency carrier, comprises dielectric 1/ dielectric 2 patterns of physical step etc.For the application in the 380nm-800nm wave band, master grating 1727 generally has the raster pitch less than about 250nm, the dutycycle that changes, the height of the modulation between the 5nm-200nm in 5%-95% (more preferably at 20%-80%) scope.Some examples that are applicable to the material of master grating comprise organic dielectric and inorganic dielectric, and this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), for example MgF ₂Fluoride, sulfide, silicon nitride etc.Except shown in binary (rectangle) master grating pattern, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine and/or trapezoidal grating pattern.In fact, any patterned layer that plays the sedimentary deposit effect of disturbing continuously coating all can be used as master grating.

[259] comprising first section 1765 with the FBAR film of interlude 1767 is to be shown by two kinds of different materials to form.As shown in Figure 54, first section 1765 is axially heterogeneous, periodic refractive index modulator elements, this first section 1765 comprises first multilayer 1775, every layer all has first refractive index and first thickness, be arranged alternately with second multilayer 1785, every layer of this second multilayer 1785 all has second refractive index and second thickness.Select in first multilayer and second multilayer every layer material and bed thickness, provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two-layer different layer material, can adopt more than two kinds of different layer materials.The material that is fit to of first and/or second multilayer comprises organic and inorganic dielectric matter.

[260] interlude 1767 that comprises axially non-homogeneous and horizontal non-homogeneous periodic refractive index modulation areas easily by with first section 1765 in the same material of employing make.In this case, generally deposition first section 1765 and interlude 1767 in same process for example, adopts conventional vacuum deposition process to deposit.Usually, deposition interlude 1767 is so that first pair of thin layer to the small part meets the shape of master grating and provide along the periodic undulations on the plane of substrate 1790.The alternately index distribution (that is, at xsect with vertically on all provide periodic refractive index modulate) of device X-Y plane at a plurality of lengthwise positions place is provided in these 1715 generations that rise and fall.Therefore, form the little ridge of A-panel in X-Y cross-section with horizontal periodic refractive index modulation heterogeneous.Each little ridge all comprises more than first individual regional, and each of these more than first zones all have first width and first refractive index, and with more than second regional replacing, each of these more than second zones all have second width and second refractive index.The thickness of each little ridge and dutycycle all change (for example, surpassing 99% from changing into less than 1%) continuously.This fluctuating produces in the sensitive surface in coating and postpones.In fact, initial net grain surface 1727 and wavy coating 1715 are to postpone to work in 1755 the face to total film all.Obviously, postpone generally to postpone in the face greater than initial master grating in the face by coating design and/or coated technique introducing.Expediently, film is that 1755 material and bed thickness generally make interlude 1767 also can play the effect of inner refractive index match block.

[261] although only having described the first film according to interlude 1762 and 1767 is that 1705 and second film is the undulating horizon in 1755, in fact, the border between the wavy and non-undulating horizon may not be clearly.In fact, whole in many cases film 1705 and/or 1755 will be risen and fallen, outermost layer have minimum relief intensity (along the Wave crest and wave trough difference in height of coating surface＜＜1nm).Under any circumstance, postpone in the face to provide by Distribution Effect.More specifically, it is neighbouring maximum that delay is distributed in female layer in the face, and reduce gradually towards the direction of outermost coating.This distribution also is discontinuous, because a plurality of parts that there is coating thickness in material variations in refractive index part in the transverse plane do not occurring.

[262] grating that is included in cascade two band coatings heterogeneous on the single substrate helps the increase of obtainable delay.Usually, need the anglec of rotation of alignment light grid line 722 and 727, rather than these two groups of grid strokes of transverse translation.Any non-aligned of the anglec of rotation will show the reduction of the linear delay of adjusting delayer and the increase that circle postpones.The grating that is included in cascade two band coatings heterogeneous on the single substrate also provides the dichroic delayer, and wherein the grating of two band coatings is aligned with respect to their grid line non-parallel and non-perpendicularly.

[263] obvious, this global function A/-C-panel is adjusted delayer and is come down to the three-D volumes holographic element, and it has the horizontal modulation period constant with respect to thickness, and has the fluctuating range of warbling along film thickness direction.

[264] advantageously, provide and postpone in the face of delay and this global function A/-C-panel of negative face external delays is adjusted delayer and easily is manufactured to full dielectric and adjusts delayer with definition axle.In addition, postpone in the tru(e)ing face easily according to demands of applications (for example, special LCoS family device) and the amplitude of face external delays.In addition, the AR characteristic also is optimized to make the be not adjusted restriction of undesirable cross polarization reflection of delayer of compensation panel contrast.The Distribution Effect of the A-panel delay element in the coating has guaranteed low-birefringence (it helps to produce low cross polarization reflection) and has increased the band coating grating that the A-panel that does not have the coating grating relatively postpones.The part conformal spreading that for example is provided with in the vacuum deposition chamber of routine guarantees not exist the cap structure hole.As a result, to adjust the optical projection system that delayer is used for based on polarization be desirable to this global function A/-C-panel.

[265], the LCOS device 1800 that comprises integrated grating adjustment delayer and display panel covered substrate is shown with reference to Figure 55.The grating trim retarders sub-assembly comprises that film is 1805, and this film is the horizontal raster 1822 that postpones in the 1805 axial gratings 1860 that comprise the display surface external delays, the display surface and simultaneously in the display surface and the branch 1810 of face external delays.This film is 1805 to be positioned on the first surface of the first transparent covered substrate 1890, its also comprise refractive index matching film be 1861 and selectable etching to stop film be 1821.The second surface of transparent covered substrate 1890 forms liquid crystal display sub-assembly 1855 with second substrate 1895 of display.The top-level metallic reverberator of this adjustment delayer sub-assembly 1805 on being positioned at silicon backboard (substrate) 1895 forms the lc unit gap, and LC molecule 1 865 is arranged in this cell gap.

[266] forming film by deposition form birefringent antireflection (FBAR) film system on master grating is 1805.Master grating 1822 is shown as including a plurality of stylobates that are arranged alternately with a plurality of grooves (being illustrated as being filled with part FBAR film system), and this master grating 1822 is horizontal periodic refractive index modulator elements heterogeneous.Preferably, select the width of these stylobates and groove so that the wavy section formation of this master grating and/or FBAR provides the horizontal zero level sub-wave length grating of form birefringent in the face.Generally by being the master grating 1822 of net grain surface in essence from being positioned at etch stop layer 1821 etchings on the transparency carrier 1890 or peeling off the top dielectric preparation.Replacedly, adopt another kind of technology to prepare patterned surface, space.For example, this master grating replacedly is prepared as patterned photoresist layer on etch substrate (for example shown in Figure 40), the transparency carrier, comprises dielectric 1/ dielectric 2 patterns of physical step etc.For the application in the 380nm-800nm wave band, master grating 1822 generally has the raster pitch less than about 250nm, the dutycycle that changes, the height of the modulation between the 5nm-200nm in 5%-95% (more preferably at 20%-80%) scope.Some examples that are applicable to the material of master grating comprise organic dielectric and inorganic dielectric, and this inorganic dielectric for example can be metal oxide (SiO for example ₂, Al ₂O ₃, Ta ₂O ₅, Nb ₂O ₅, HfO ₂, TiO ₂, niobium carbide, titanizing niobium), for example MgF ₂Fluoride, sulfide, silicon nitride etc.Except shown in binary (rectangle) master grating pattern, other possible diffraction surfaces shape comprises zigzag (triangle), glitters, sine and/or trapezoidal grating pattern.In fact, any patterned layer that plays the sedimentary deposit effect of disturbing continuously coating all can be used as master grating.

[267] comprising first section 1860 with the FBAR film of interlude 1862 is 1850 to be shown by two kinds of different materials and to form.As shown in Figure 55, first section 1860 is axially heterogeneous, periodic refractive index modulator elements, and this first section 1860 comprises first multilayer 1870, and every layer all has first refractive index and the first thickness 1871d ₁, being arranged alternately with second multilayer 1880, every layer of this second multilayer 1880 all has second refractive index and the second thickness 1881d ₂Select in first multilayer and second multilayer every layer material and bed thickness, provide the negative birefringent zero level sub-wave length grating of facial contour formula so that this structure forms.Usually, every layer of first and second multilayers generally all comprises about 10-500 layer, and more typical is about 50-110 layer.Bigger difference (for example greater than 0.5, being preferably greater than 0.7) generally will maximize form birefringent and minimize the thickness of coating between first and second refractive indexes.In addition, by with bed thickness d ₁Or d ₂Elect as and similar basically or identically generally also can maximize form birefringent.For the 380nm-800nm wave band, dutycycle is between 20%-80%, and every layer bed thickness of first and second multilayers is generally all greater than about 1nm and less than about 100nm.Although alternate films system is illustrated as only two-layer different layer material, can adopt more than two kinds of different layer materials.The material that is fit to of first and/or second multilayer comprises organic and inorganic dielectric matter.

[268] interlude 1862 that comprises axially non-homogeneous and horizontal non-homogeneous periodic refractive index modulation areas easily by with first section 1860 in the same material of employing make.In this case, generally deposition first section 1860 and interlude 1862 in same process for example, adopts conventional vacuum deposition process to deposit.Usually, deposition interlude 1862 is so that first pair of thin layer to the small part meets the shape of master grating and provide along the periodic undulations on the plane of substrate 1890.The alternately index distribution (that is, at xsect with vertically on all provide periodic refractive index modulate) of device X-Y plane at a plurality of lengthwise positions place is provided in these 1810 generations that rise and fall.Therefore, form the little ridge of A-panel in X-Y cross-section with horizontal periodic refractive index modulation heterogeneous.Each little ridge all comprises more than first individual regional, and each of these more than first zones all have first width and first refractive index, and with more than second regional replacing, each of these more than second zones all have second width and second refractive index.The thickness of each little ridge and dutycycle all change (for example, surpassing 99% from changing into less than 1%) continuously.This fluctuating produces in the sensitive surface in coating and postpones.In fact, initial net grain surface 1822 and wavy coating 1810 are to postpone to work in 1805 the face to total film all.Obviously, postpone generally to postpone in the face greater than initial master grating in the face by coating design and/or coated technique introducing.Expediently, film is that 1805 material and bed thickness generally make interlude 1862 also can play the effect of inner refractive index match block.

[269] although only described undulating horizon according to interlude 1862, in fact, the border between the wavy and non-undulating horizon may not be clearly.In fact, whole in many cases film 1850 will be risen and fallen, outermost layer have minimum relief intensity (along the Wave crest and wave trough difference in height of coating surface＜＜1nm).Under any circumstance, postpone in the face to provide by Distribution Effect.More specifically, it is neighbouring maximum that delay is distributed in female layer in the face, and reduce gradually towards the direction of outermost coating.This distribution also is discontinuous, because a plurality of parts that there is coating thickness in material variations in refractive index part in the transverse plane do not occurring.

[270] routinely, liquid crystal cells sub-assembly 1855 also comprises oriented layer 1866 and preceding transparency conductive electrode 1867, and this oriented layer for example is the inorganic layer of polymeric layer or inclination evaporation, and this preceding transparency conductive electrode is for example made by tin indium oxide (ITO).Sentence VAN-model LC orientation in pre-tilt angle 1868 this LCoS display is shown.According to the covering among Fig. 3 coupling compensation image, relevant LC dip plane generally is not parallel to and also is not orthogonal to grating vector (being shown parallel among Figure 55) and is oriented.Because the use of positive single shaft LC material in pre-tilt and the display, the remaining A/-C-panel that is in the display of light closure state postpones by integrated adjustment delayer compensator 1805 compensation.

[271] in order to provide high yield integrated compensator/display, consider the interior delay amplitude of nominal plane of two retarder element, can be offset by the rough position angle that mechanical rotation covered substrate in this device plane applies between (impose) adjustment retarder element 1805 and the display element 1855.The single accurate adjustment (part) of each integrated compensator/display can comprise other non-mechanical means, for example LC pitch angle voltage is switched to closed condition and always reveals intensity with further reduction.Should be noted that, thereby do not make the suitable major part of the voltage that applied can pass the LC layer if the ITO layer fully insulate with the LC layer), so A-panel grating 1822/1862 and-C-panel grating 1860/1862 element can be assigned to two surfaces of covered substrate.

[272] be similar to reference to Figure 17,18,24 and 37 embodiment that describe, manufactured so that the A-panel grating of the global function A/-C-panel grating trim retarders of describing with reference to Figure 48,49,54 and 55 and-C-panel grating partially overlaps (that is, occupying same position in the space) at least.More specifically, each among these embodiment all comprise provide A-panel grating performance and-overlay segment (for example series of layers) of C-panel grating performance.In reference Figure 17,18,24 and 37 embodiment that describe, overlay segment comprises the axial non-homogeneous zone that forms horizontal non-homogeneous grating stylobate.In reference Figure 48,49,54 and 55 embodiment that describe, overlay segment comprises the axial non-homogeneous zone of filling horizontal non-homogeneous master grating, with and/or determine that this master grating profile is to provide the axial non-homogeneous zone of the A-panel delay of increase by producing extra horizontal raster element (being little ridge).For example, for the latter and with reference to Figure 49, the first film film is 1605 to comprise axial non-homogeneous element 1650 and horizontal non-homogeneous element 1610, and wherein these two elements overlap in overlay segment 1662.

[273] in the above embodiments each, global function A/-C-panel is adjusted delayer and is integrated (that is, integrating with in the cover plate of reflective LCD panel) as compensator independently or with other optical element.Obviously, the foregoing description only is provided as an example, and for those skilled in the art, under the conditions without departing from the spirit and scope of the present invention, various changes, replacement structure and/or equivalent may be utilized.Particularly, although the adjustment delayer according to the VAN model LCoS that is used for compensating the projection display has been discussed the present invention, but it will be appreciated by those skilled in the art that, it also is useful that global function A/-C-grating light delay device provided by the invention adopts the transmission or the reflective LCD panel of other LC phase place/operator scheme (for example, vertical orientated to row, π unit to row, twisted-nematic, in-plane switching to row, planar orientation ferroelectrics etc.) for compensation.

[274] in addition, according to another embodiment, global function grating delayer is merged in one or two substrate of transmission type LCD panel, and wherein the orientation of grid stroke is constructed by the fast/slow axis of the relative LCD layer of scheduled volume.Aspect the overclocking coupling between grating delayer sub-assembly and LCD sub-assembly, the slow axis of A-panel delayer all needn't be oriented in vertical direction.The A-panel that is configured in the grating delayer sub-assembly in integrated compensator/display by this way by predetermined quantity postpone and-the C-panel postpones: the dark stage of the panel in the circular cone illumination (electricity drives or do not drive) has minimum as far as possible light and leaks to projection display screen.Replacedly, be used as in the transmission type LCD projector equipment independently contrast compensation device based on the optical delay of grating.

[275] although optical delay of the present invention is described to incorporate into the liquid crystal cells sub-assembly or as the autonomous device in the little display projection system of liquid crystal, that this optical delay and other optical element is integrated equally within the scope of the present invention.For example, according to other embodiment, light delay device is the part with optical device of wiregrating, and wherein this wiregrating provides two attenuation functions, and the grating delayer provides delay feature; The orientation of two attenuators (polarizer) and delayer is by non-parallel/non-perpendicular aligning.In general the application, assembling device is non-homogeneous elliptical polarizers, perhaps more preferably is non-homogeneous circuit polarizer.

[276] in addition, although described light delay device of the present invention, in using, other use this light delay device to be also included within the scope of the present invention according to the compensated birefringence in the display panels.For example, imagine that this light delay device is used for the embodiment that various CD and/or DVD use (for example, in the Polarization Control up to 800nm wavelength place).

[277] be meant the adjustment delayer that comprises dielectric layer although should also be noted that the foregoing description great majority, the present invention also comprises the grating light delay device of the layer that comprises other type.For example, the grating delayer design that comprises semiconductor layer can be applicable to infrared and near infrared (IR/NIR) wavelength applications in, wherein this semiconductor is transparent on substantially and its purpose is to produce the big delay with the surface structure that is rather narrow and/or the repeat layer that quite approaches in the C-panel postpones.In addition, according to some embodiment, comprise that the reflective multilayer film of A-panel and C-panel grating can be designed and be manufactured on the transparent or opaque substrate.In addition, also have some other embodiment to comprise: one or more layers the thin metal film in-C-panel grating or around it to be merged into the induction transmission film, so that the UV/IR except that delay compensation to be provided cutoff wavelength.

[278] be also noted that, although be described to have periodic modulation by delayer in the face that on master grating, applies the film coating acquisition, and this delayer target is evenly to postpone and axial distribution, A-panel raster pitch can be trimmed in the above described manner crosses over the XY changes in coordinates, and/or aim at grating vector (and grid stroke direction) in the mode of spatial variations so that can obtain the space variable delayer.This equipment may be useful aspect the point-spread function of shaping optical system, perhaps may be used for polarizer.

[279] in each of superincumbent embodiment, generally adopt a kind of manufacturing FBAR (comprising wavy FBAR) in the multiple deposition technique well known in the art.For example, some deposition techniques commonly used comprise chemical vapor deposition (CVD), plasma enhanced CVD, electron beam evaporation, thermal evaporation, sputter and/or ald.Obviously, can in sputtering chamber commonly used, deposit these coatings.

[280] in each of superincumbent embodiment, generally adopt a kind of manufacturing A-panel grating in multiple deposition technique well known in the art and the photoetching composition technology.According to an embodiment, form A-panel grating by deposition-etch stop layer on transparency carrier, this etch stop layer for example can be the 10nm alumina layer.Then for example can be by the etch stop layer of above-mentioned a kind of deposition technique coating to form stylobate with the coating of one or more layers dielectric layer, this one or more layers dielectric layer for example is the 50nm silicon oxide layer.This one or more layers dielectric layer has patterned resist layer, and it is by adopting a kind of formation the in the multiple photoetching technique.For example, some photoetching techniques commonly used comprise nano print photoetching, holography/interference lithography, beamwriter lithography, X-ray lithography or photoetching process.In case form the resist layer have pattern, this is with this one or more layers dielectric layer of a kind of etching in the multiple lithographic technique.For example, some lithographic techniques commonly used comprise reactive ion etching, plasma etching and wet etching.After the etching technics, finish the removal of photoresist and the deposition of light cap rock.Preferably, cap rock deposits so that this cap rock is not filled these grooves basically with the angle that tilts.Subsequently, AR is coated with and is deposited upon on the cap rock, and this AR coating for example is MgF ₂Quarter-wave layer.

[281] replacedly, etching and form A-panel grating not.For example, according to an embodiment, this one or more layers dielectric layer intention forms and is deposited on the stylobate that is coated with on the patterned sacrifice layer.By this sacrifice layer of continuous flushing, expose stylobate.

[282] only provided by A-panel grating (for example, not having wavy FBAR) among the embodiment that postpones in the face, A-panel grating selectively adopts the Fiber Bragg Grating FBG manufacturing technology to form.When producing Fiber Bragg Grating FBG, the UV light beam that causes disturbs and produces to change and mix the diffraction pattern of Ge fiber core refractive index.When these technology were used to make grating trim retarders, planar substrates or its coating were doped with suitable material interfering the UV light beam with after producing the horizontal raster pattern by being exposed in the surface.Other technology comprises with the mask motherboard carries out the nanoscale impression, and it can comprise or not comprise substep-iterative process.

[283] as for being applicable to the manufacturing process that produces the master grating pattern, suitable when the above-mentioned technology of expection stylobate/groove structure is provided, for example interference lithography and nanoscale stamping technique.Other technology is included in and produces LC oriented layer, fixed bed and have the inclination evaporation of adopting in the dielectric film of rod structure.For example, SIO _xOriented layer has the nanometer groove and total bed thickness is generally less than 10nm.This can be made as thickness and the cycle that is applicable to as master grating.The optical device of the general type by on substrate, can obtaining to be called structural membrane (STF) with inclination flux angle evaporation.Column construction be porous and seal coat generally be used for the reinforcing membrane reliability.According to the present invention, seal coat can be the FBAR design, and wherein, after the routine coating, postponing in the face of column construction layer is further increased.The groove of the master grating layer of porous is by complete filling, and it helps the reliability aspect.Another method of patterned substrate can comprise that " punching press " that be similar to CD (CD) duplication process goes out the non-birefringence organic layer of spin coating on the substrate, carries out nano-pattern by exerting pressure and transmit or the like.At C.H.Chiu et al., " Nanoimprinting-lithography-induced self-aligned liquid crystal for novelmultifunctional optical films ", Appl.Phys.Lett.88 has described the latter in 073509 (2006) in more detail.

[284] therefore, scope of the present invention is only limited by the scope of additional claims.

Claims (31)

1, a kind of optical delay, this optical delay comprises:

Comprise first multilayer and have second refractive index and the axial non-homogeneous element of second multilayer of second thickness with first refractive index and first thickness, described first multilayer and described second multilayer alternately select described first thickness and second thickness and described first refractive index and described second refractive index that the zero level sub-wavelength grate structure of negative face external delays is provided with formation;

Comprise more than first zones with first refractive index and first width and horizontal non-homogeneous element with more than second zones of second refractive index and second width, described more than first zones are alternately regional with described more than second, select described first width and described second width and described first refractive index and described second refractive index to provide the zero level that postpones in face sub-wavelength grate structure with formation;

Be used to support at least one substrate of described axial non-homogeneous element and described horizontal non-homogeneous element.

2, optical delay according to claim 1 comprises overlay segment, partially overlaps at least at horizontal non-homogeneous element described in the described overlay segment and described axial non-homogeneous element, and described overlay segment provides simultaneously and postpones in the face and negative face external delays.

3, optical delay according to claim 2, wherein said overlay segment comprises the etch areas of described axial non-homogeneous element.

4, optical delay according to claim 3, the modulation height of wherein said horizontal non-homogeneous grating is between 10nm-3 μ m.

5, optical delay according to claim 2, wherein said overlay segment comprise wavy section of described axial non-homogeneous element.

6, optical delay according to claim 5, wherein said wavy section comprises a plurality of undulating horizons of determining horizontal non-homogeneous master grating profile.

7, optical delay according to claim 6, the modulation height of wherein said master grating is between about 5nm-200nm.

8, optical delay according to claim 6, the dutycycle of wherein said master grating is between about 20%-80%.

9, optical delay according to claim 6, wherein said master grating provide in first and postpone, and described wavy section provides delay in second, and postpones in wherein said second to postpone in described first.

10, optical delay according to claim 6, wherein said a plurality of undulating horizons have same modulation period, and the modulation of wherein said a plurality of undulating horizons height is along with the distance with described master grating reduces gradually.

11, according to the described optical delay of each claim among the claim 2-10, wherein said axial non-homogeneous element is a form birefringent film antireflection element.

12, optical delay according to claim 11, wherein said at least one substrate comprises the substrate of substantial transparent, and wherein said form birefringent film antireflection element and described horizontal non-homogeneous element are positioned on first side of substrate of described substantial transparent, and antireflecting coating is positioned on second opposite side of substrate of described substantial transparent.

13, optical delay according to claim 11, wherein said at least one substrate comprises the substrate of substantial transparent, and wherein said form birefringent film antireflection element and described horizontal non-homogeneous element are positioned on first side of substrate of described substantial transparent, and the second form birefringent film antireflection element is positioned on second opposite side of substrate of described substantial transparent.

14, optical delay according to claim 11, wherein said at least one substrate comprises first substrate that is connected to second substrate, and at least one in described first substrate and described second substrate is used to support described axial non-homogeneous element and horizontal non-homogeneous element.

15, optical delay according to claim 11, wherein said at least one substrate are the covered substrates in the display panels, and wherein said axial non-homogeneous element and described horizontal non-homogeneous element are positioned on first side of described covered substrate.

16, optical delay according to claim 11, wherein said horizontal non-homogeneous element comprises the zone that is etched of described form birefringent film antireflection element.

17, optical delay according to claim 11, wherein said form birefringent film antireflection element comprises at least one antireflecting coating, is used to be reduced in the reflection at least one place of grating-grated interface, air-grated interface, substrate-grated interface and substrate-air interface.

18, optical delay according to claim 17, wherein select described first and second refractive indexes and described first and second thickness of described first and second multilayers, to be provided for compensating the birefringence of display panels and birefringent external delays of described at least one antireflecting coating.

19, according to the described optical delay of each claim among the claim 1-10, wherein said axial non-homogeneous element is transparent at the 380nm-800nm wave band, and the face external delays of 0nm to 1000nm scope is provided for any wavelength between the 380nm-800nm.

20, optical delay according to claim 19, wherein said horizontal non-homogeneous element is transparent at the 380nm-800nm wave band, and provides for any wavelength between the 380nm-800nm in the face of 1nm to 250nm scope and postpone.

21, according to the described optical delay of each claim among the claim 1-10, each all is made of wherein said horizontal non-homogeneous element and described axial non-homogeneous element isotropic material.

22, according to the described optical delay of each claim among the claim 1-10, each all is made of wherein said horizontal non-homogeneous element and described axial non-homogeneous element dielectric material.

23, according to the described optical delay of each claim among the claim 1-10, wherein said horizontal non-homogeneous element, described axial non-homogeneous element and described at least one substrate are formed for compensating the full-inorganic dielectric of the residual birefringence in the display panels and adjust delayer.

24, according to the described optical delay of each claim among the claim 1-10, wherein select described more than first zones and described more than second zones of described first multilayer of described axial non-homogeneous element and described second multilayer, described horizontal non-homogeneous element, to strengthen based on the system contrast in little display projection system of polarization.

25, according to the described optical delay of each claim among the claim 1-10, every layer described first refractive index of wherein said first multilayer and described second multilayer and the difference of described second refractive index are greater than about 0.5.

26, a kind of optical delay that adopts is to strengthen based on the system contrast method in the optical projection system of liquid crystal display, and described method comprises:

The location is as the optical delay that each claim limited among the claim 1-10, so that the residual retardance of the display panels in described optical projection system is compensated basically in described optical projection system.

27, a kind of optical projection system based on LCD, described optical projection system comprises:

Light source;

First polarizer, its light that is used to receive from described light source also transmits first linearly polarized light with first linear polarization axle;

Display panels, it is used for described first linearly polarized light of optical modulation, and described display panels has residual birefringence;

Second polarizer, it is used to receive the light through optical modulation, and is used to transmit second linearly polarized light with second linear polarization axle;

Projecting lens, it is used for described second linearly polarized light is projected in display screen; And

Optical delay, it is used to compensate the residual birefringence of described display panels, and each claim limits among described optical delay such as the claim 1-10.

28, a kind of manufacture method of light delay device, described method comprises:

Net grain surface is provided on substrate, and described net grain surface is showed the interior birefringence of appearing; And

The multi-layer thin membrane system that the deposition refractive index replaces on described net grain surface, so that described thin layer constitutes the profile of described net grain surface basically so that a plurality of undulating horizons to be provided, described a plurality of undulating horizons are showed appear interior birefringence and the outer birefringence of face.

29, the manufacture method of optical delay according to claim 28, wherein deposit described alternately refractive index multi-layer thin membrane system so that described multilayer undulating horizon has same modulation period, and make the modulation height of described multilayer undulating horizon along with reducing gradually with the distance of described net grain surface.

30, the manufacture method of optical delay according to claim 29, wherein, deposit multi-layer thin membrane system that described refractive index replaces so that described light delay device is provided at that A-panel in the preset range postpones and-the C-panel postpones, to improve the system contrast grade based on the optical projection system of LCD.

31, a kind of manufacture method of optical delay, described method comprises:

The multi-layer thin membrane system that the deposition refractive index replaces on substrate, the multi-layer thin membrane system that described refractive index replaces provides-C-panel optical grating construction; And

The thickness section etching of the multi-layer thin membrane system that described refractive index is replaced for the transverse area that replaces so that A-panel optical grating construction to be provided.

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