CN101290366B

CN101290366B - Polarization beam splitter and polarization conversion element

Info

Publication number: CN101290366B
Application number: CN2007103076093A
Authority: CN
Inventors: 前田育夫; 柴田一司
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2006-12-28
Filing date: 2007-12-28
Publication date: 2011-06-08
Anticipated expiration: 2027-12-28
Also published as: TWI381192B; JP5209932B2; TW200844481A; JP2008181074A; CN101290366A

Abstract

A polarization beam splitter is effective when light to undergo polarization-splitting has an incidence angle that falls in a range of 54 degrees through 66 degrees. The polarization beam splitter includes, between two transparent substrates, an adhesive layer configured to adhere to a first transparent substrate of the two transparent substrates, two or more types of dielectric multilayer films having different design basis wavelengths, and a single-layer dielectric film. The dielectric multilayer films and the single-layer dielectric film form a polarization split film, which performs a polarization split function with respect to light that is substantially in the visible wavelength region.

Description

Polarization beam apparatus and polarization conversion device

Technical field

The present invention relates to polarization beam apparatus (polarization beam splitter) and polarization conversion device.

Background technology

Polarization beam apparatus generally includes the polarization separating film that is interposed between a pair of transparency carrier.Polarization beam apparatus is separated into the have orthogonal plane of polarization optical element of " transmitted light and reflected light " with incident light.Polarization beam apparatus is used for various types of optical device.

When polarization beam apparatus is used for " using monochromatic optical device " as optical pickup apparatus, can be than being easier to realize good polarization separation characteristic.But, when polarization beam apparatus is used as polarization conversion device in the liquid crystal projection apparatus, then need " having good polarization separation characteristic " at whole visible wavelength range.

Patent documentation 1 has disclosed a kind of polarization beam apparatus, and wherein polarization separating film forms dielectric multilayer film (dielectric multiplayer film), thereby realizes good polarization separation characteristic on visible wavelength range.

In the polarization beam apparatus that patent documentation 1 discloses, dielectric multilayer film is arranged between two transparency carriers.Each dielectric multilayer film is by alternately gas deposition high index of refraction material and low-refraction material form.Dielectric multilayer film is " two dielectric multilayer films of corresponding different designs basis wavelength ".Above-mentioned two dielectric multilayer films have different " combination of high index of refraction material and low-refraction material ".High index of refraction material in two dielectric multilayer films all has 2.6 or bigger refractive index.

According to the specific embodiment of patent documentation 1, realized good polarization separation characteristic.Particularly, the incident angle scope is 45 degree ± 2 degree relatively, and wavelength coverage is the light of 410nm to 700nm, and the transmissivity of P polarized component is 80% or higher, and the transmissivity of S polarized component is 0% substantially.

The embodiment of record not have detailed description " in the light beam diffusion barrier in each dielectric multilayer film the quantity of laminate layers (laminated layer) " in the patent documentation 1.The present inventor has designed a kind of film according to the summary of the invention that patent documentation 1 discloses.When the quantity of laminate layers was roughly 60, P polarized component relative wavelength scope is 400nm to the optical transmission rate of 700nm was 80% or higher.But the S polarized component is 400nm to the optical transmission rate of 700nm with respect to wavelength coverage is about 15%, is not enough with regard to it with regard to aspect the polarization separation properties.

When the quantity of the laminate layers of dielectric multilayer film is roughly 120, the relative wavelength scope be 400nm to 550nm, the transmissivity of P polarized component be substantially 100% and the transmissivity of S polarized component be 0% substantially, it has very good polarization separation function.But, can realize that the relative visible wavelength range of wavelength coverage of good separation characteristic is narrow.Therefore, can not realize the polarization separation function to ruddiness.

Consider from the foregoing aspect, in order to realize in each dielectric multilayer film, need seeming the very large laminate layers of quantity as the good polarization separation function described in the polarization beam apparatus that discloses among patent documentation 1 embodiment.If the laminate layers quantity of each dielectric multilayer film is too much, forming polarization separating film will expend time in, and this is unfavorable for improving the efficient of making polarization beam apparatus.

And, in the polarization beam apparatus that patent documentation 1 embodiment describes, used " glass of high refractive index " with 1.85 refractive indexes.This means that the high index of refraction material demand that uses in the dielectric multilayer film has very high 2.6 refractive index or higher refractive index.This glass of high refractive index and high index of refraction material all compare expensive, and this makes and is unfavorable for producing polarization beam apparatus in batches with low-cost and high-level efficiency.

Patent documentation 1: Japanese Unexamined Patent Application No.H11-211916.

Summary of the invention

The invention provides a kind of polarization beam apparatus and a kind of polarization conversion device, in order to eliminate one or more above-mentioned rough sledding.

The preferred embodiments of the present invention provide a kind of polarization beam apparatus and a kind of polarization conversion device that comprises this polarization beam apparatus, wherein polarization separating film laminate layers with lesser amt in each dielectric multilayer film forms, and at whole wide visible wavelength range, be specially the scope of 400nm, realize good polarization separation function to 750nm.

Embodiments of the invention provide a kind of polarization separation polarization of incident light beam splitter that is used for, wherein when the light that will carry out polarization separation have fall into 54 spend in 66 degree scopes incident angle the time, this polarization beam apparatus is effective, this polarization beam apparatus comprises between two transparency carriers: bonding coat is configured to adhere to first transparency carrier in two transparency carriers; Two or more have the dielectric multilayer film of different designs basis wavelength; Individual layer dielectric film (dielectric film), wherein two or more dielectric multilayer films comprise high refractive index film, middle refractive index film, each has the optical thickness according to respective design basis wavelength, and wherein high refractive index film and middle refractive index film alternatively laminated form the multilayer of even number; The individual layer dielectric film is set in place on a side of the bonding coat of the dielectric multilayer film of bonding coat side, and this individual layer dielectric film is with identical corresponding to the film of the described ground floor that is arranged in a dielectric multilayer film on the bonding coat side; Two or more dielectric multilayer films and individual layer dielectric film form polarization separating film, and this polarization separating film comprises the light execution polarization separation function of whole visible wavelength ranges relatively substantially.

According to one embodiment of present invention, a kind of polarization beam apparatus and a kind of polarization conversion device that comprises this polarization beam apparatus are provided, wherein polarization separating film can be formed by the laminate layers of the lesser amt in each dielectric multilayer film, and relatively incident angle fall into 54 spend to 66 the degree scopes light, in the wide visible wavelength range from 400nm to 750nm, realize good polarization separation function.

Each transparency carrier is made by low-cost, that be easy to get, that refractive index falls into 1.46 to 1.58 scopes optical glass, as BK7.High refractive index film in each dielectric multilayer film can be made by the lower cost materials of refractive index about 2.3, as Nb ₂O ₅Therefore, can provide low-cost polarization beam apparatus.

Polarization beam apparatus according to the embodiment of the invention has excellent polarization separation characteristic, thereby can realize good polarization conversion characteristics with the polarization conversion device that this polarization beam apparatus forms.

Description of drawings

Other purpose of the present invention, characteristics and advantage can be read following detailed and apparent in conjunction with the drawings, wherein:

Fig. 1 is the synoptic diagram that is used to describe according to the polarization beam apparatus of the embodiment of the invention;

Fig. 2 is the figure of polarization separation function that is used to describe the polarization beam apparatus of the example 1 according to the present invention;

Fig. 3 A and Fig. 3 B are the figure how the polarization separation function that is used to describe the polarization beam apparatus of the example 1 according to the present invention depends on incident angle;

Fig. 4 A and Fig. 4 B are the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 1 of the present invention and 2;

Fig. 5 A and Fig. 5 B are the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 3 of the present invention and 4;

Fig. 6 A and Fig. 6 B are the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 5 of the present invention and 6;

Fig. 7 A and Fig. 7 B are the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 7 of the present invention and 8;

Fig. 8 is the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 9 of the present invention;

Fig. 9 is the figure that is used to describe the polarization separation function of carrying out when first multilayer film of invention example 1 only is provided;

Figure 10 is the figure that is used to describe the polarization separation function of carrying out when second multilayer film of invention example 1 only is provided;

Figure 11 is the figure that is used to describe the polarization separation function of carrying out when the 3rd multilayer film of invention example 1 only is provided;

Figure 12 is the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 10 of the present invention;

Figure 13 is the figure that is used to describe the polarization separation function of carrying out when the second and the 3rd multilayer film of invention example 1 only is provided;

Figure 14 is the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 11 of the present invention;

Figure 15 is the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 12 of the present invention;

Figure 16 A shows the polarization conversion device according to the embodiment of the invention, and Figure 16 B shows conventional polarization conversion device;

Figure 17 is the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 13 of the present invention;

Figure 18 is the figure that is used to describe according to the polarization separation function of the polarization beam apparatus of example 14 of the present invention;

Figure 19 is used for relatively when taking place to absorb in the film according to the polarization beam apparatus of example 1 with according to the figure of the characteristic variations between the polarization beam apparatus of variation 13; And

Figure 20 A is the peaked figure that the various combination that is included in the laminate layers quantity in corresponding first multilayer film to the, three multilayer films is surveyed and drawn the S polarization to Figure 20 F.

Embodiment

With reference to accompanying drawing, embodiments of the invention are described.

Fig. 1 is the synoptic diagram that is used to describe according to the polarization beam apparatus 10 of the embodiment of the invention.

Polarization beam apparatus 10 polarization separation incident lights shown in Figure 1.The incident angle that carries out the light of polarization separation is set at 60 degree.

Polarization beam apparatus 10 is included in being used between a pair of

transparency carrier

11,12 and adheres to one the bonding coat 14 and the polarization separating film 13 of described transparency carrier.

As shown in fig. 1, the shape of cross section of each

transparency carrier

11,12 is trapezoidal.Each trapezoidal base angle is set at 60 degree.When watching in the figure perpendicular to the mode of left side incidence surface, the incident light LI that carry out polarization separation is from left side incident transparency carrier 11.Therefore, incident light LI on polarization separating film 13 with 60 the degree the incident angle incidents.

On polarization separating film 13 in the light beam of incident, be reflected from polarization separating film 13 perpendicular to the polarized component in the plane of figure, and when when watching in the drawings perpendicular to the mode of right side exit surface, from the right side of transparency carrier 11 with S polarization LS outgoing polarization beam apparatus 10.And the polarized component transmission that is parallel to this figure is by polarization separating film 13 and bonding coat 14, when when watching in the drawings perpendicular to the mode of right side exit surface, from the right side of transparency carrier 12 with P polarization LP outgoing polarization beam apparatus 10.Therefore, be polarized with the incident light LI of 60 degree angle incidents polarization beam apparatus 10 shown in Figure 1 and be separated into S polarization LS and P polarization LP; S polarization LS and P polarization LP have the angle (includedangle) of 60 degree.

Angle between S polarization LS and the P polarization LP can become other angle that is different from 60 degree, this is to realize by base angle on adjustment transparency carrier 11 right sides and the base angle on transparency carrier 12 right sides, and the surface and the surface that P polarization LP outgoing polarization beam apparatus 10 is set of S polarization LS outgoing polarization beam apparatus 10 promptly is set.

Polarization separating film 13 comprises the dielectric multilayer film of two or more corresponding different designs basis wavelength.

In two or more dielectric multilayer films every kind high refractive index film and middle refractive index film that all has according to the optical thickness of respective design basis wavelength by alternatively laminated forms.Polarization separating film 13 has basic corresponding visible wavelength range polarisation of light separation function.

Be the example of polarization beam apparatus 10 shown in Figure 1 below.

＜example 1 〉

As shown in Figure 1, be designed to have the incident angle of 60 degree according to the polarization beam apparatus of example 1.Table 1 has shown the structure according to the polarization beam apparatus of example 1.

(table 1)

Term in the table 1 is as described below." layer " a pair of transparency carrier of expression and dielectric film in the hurdle of going up most.At " substrate " on table 1 top transparency carrier 11 corresponding shown in Figure 1.The transparency carrier 12 that " substrate " of table 1 bottom is corresponding shown in Figure 1.The transparency carrier that numerical value 1 to 46 in each layer (below be called level number 1 to 46) expression is piled up and the order of dielectric film.The material of " material " expression transparency carrier and dielectric film.The above-mentioned design basis wavelength of " centre wavelength " expression.The refractive index of " refraction coefficient " expression transparency carrier and dielectric film.For each dielectric film, the product of " thickness " expression film refractive index and film self physical thickness, corresponding above-mentioned optical thickness." physics thickness " expression aforesaid film self thickness.

For the centre wavelength of design basis wavelength is expressed as " λ 0 ".Refractive index is expressed as " n ".The physics thickness is expressed as " d ".Therefore, thickness is expressed as " nd ".In example 1, the thickness of all films " nd " all is set to λ 0/4 (=0.25 λ is expressed as 0.25 λ in table 1).

First multilayer film in the table 1, the corresponding above-mentioned dielectric multilayer film of second multilayer film and the 3rd multilayer film.First to the 3rd multilayer film has different central wavelength lambda 0, i.e. the design basis wavelength.

In the hurdle of the material of each dielectric film, Nb ₂O ₅Corresponding Nb ₂O ₅Nb ₂O ₅/ SiO ₂Corresponding Nb ₂O ₅And SiO ₂Potpourri.Identical expression can be used for following description.

Each transparency carrier (" substrate " of table 1 top and bottom) is made by the material that is called BSC7 (title of the product that HOYA company makes), and it is to use optical glass material the most widely, is commonly referred to BK7, has 1.52 refractive index.

The dielectric film that forms level number 1 on table 1 head substrate (transparency carrier 11 among Fig. 1) is made thickness 0.25 λ 0 to obtain relative central wavelength lambda 0=840nm.Particularly, be arranged on film Nb ₂O ₅/ SiO ₂Nb in the potpourri ₂O ₅And SiO ₂Blending ratio to obtain 1.572 refractive index.The actual physics thickness is 133.60nm, and optical thickness is 133.60 * 1.572=210.0=840/4.In corresponding two the middle refractive index films of the dielectric film of level number 1 one, dielectric multilayer film is sandwiched between between two middle refractive index films (below be called " insert and put with in refractive index film ").

First multilayer film (first kind of dielectric multilayer film) comprises 14 layers of corresponding level number 2 to 15, has the centre wavelength (first kind of design basis wavelength) of λ 0=610nm.In first multilayer film, the layer of even number level number is by high index of refraction material Nb ₂O ₅Make (at the refractive index n H1=2.213 of centre wavelength 610nm).In first multilayer film, the layer of odd number level number is by middle refractive index substance Nb ₂O ₅/ SiO ₂Make, wherein regulate mixing ratio in the mode of the refractive index n L1=1.613 of centre wavelength 610nm with acquisition.High refractive index film and middle refractive index film alternatively laminated are to form 14 layers in first multilayer film.

High refractive index film has 68.90 physics thickness (d), 2.213 refractive index (n), thereby thickness (nd) is 68.90 * 2.213=152.4=610/4.Middle refractive index film has 94.60 physics thickness (d), 1.613 refractive index (n), thereby thickness (nd) is 94.60 * 1.613=1 52.5=610/4.

Second multilayer film (dielectric multilayer film in second) comprises 14 layers of corresponding level number 16 to 29, has the centre wavelength (second kind of design basis wavelength) of λ 0=830nm.In second multilayer film, the layer of even number level number is by high index of refraction material Nb ₂O ₅Make (at the refractive index n H2=2.170 of centre wavelength 830nm).In second multilayer film, the layer of odd number level number is by middle refractive index substance Nb ₂O ₅/ SiO ₂Make, wherein regulate mixing ratio in the mode of the refractive index n L2=1.623 of centre wavelength 830nm with acquisition.High refractive index film and middle refractive index film alternatively laminated are to form 14 layers in second multilayer film.

High refractive index film has 95.60 physics thickness (d), 2.170 refractive index (n), thereby thickness (nd) is 95.60 * 2.170=207.5=830/4.Middle refractive index film has 127.9 physics thickness (d), 1.623 refractive index (n), thereby thickness (nd) is 127.9 * 1.623=207.5=830/4.

The 3rd multilayer film (dielectric multilayer film in the 3rd) comprises 14 layers of corresponding level number 30 to 43, has the centre wavelength (the third design basis wavelength) of λ 0=940nm.In the 3rd multilayer film, the layer of even number level number is by high index of refraction material Nb ₂O ₅Make (at the refractive index n H3=2.159 of centre wavelength 940nm).In the 3rd multilayer film, the layer of odd number level number is by middle refractive index substance Nb ₂O ₅/ SiO ₂Make, wherein regulate mixing ratio in the mode of the refractive index n L3=1.616 of centre wavelength 940nm with acquisition.High refractive index film and middle refractive index film alternatively laminated are to form 14 layers in the 3rd multilayer film.

High refractive index film has 108.8 physics thickness (d), 2.159 refractive index (n), thereby thickness (nd) is 108.8 * 2.159=235=940/4.Middle refractive index film has 145.4 physics thickness (d), 1.616 refractive index (n), thereby thickness (nd) is 145.4 * 1.616=235=940/4.

In first to the 3rd multilayer film, the 3rd multilayer film is positioned on bonding coat (level number 46) side.Be deposited on dielectric film (level number 44) on the 3rd multilayer film and be with first tunic identical (having identical component and thickness) of the 3rd multilayer film (be the individual layer dielectric film of level number 30; Particularly, this film (refractive index in 940nm centre wavelength is nH3=2.159) is by high index of refraction material Nb ₂O ₅Make.

Dielectric film (level number 45) is formed on the individual layer dielectric film (level number 44).The thickness that dielectric film (level number 45) is used to be implemented in 840nm centre wavelength is 0.25 λ 0.Particularly, at film Nb ₂O ₅/ SiO ₂Nb is set in the potpourri ₂O ₅And SiO ₂Blending ratio to realize 1.572 refractive index.The actual physics thickness is 133.60nm, and optical thickness is 133.60 * 1.572=210.0=840/4.The dielectric film of level number 45 is identical with the dielectric film of level number 1, constitutes a pair of middle refractive index film that inserts and puts usefulness with the dielectric film of level number 1.

The dielectric film of level number 45 adheres on another substrate (transparency carrier 12 corresponding shown in Figure 1) by the bonding coat (level number 46) that is made of bonding agent.The bonding agent that constitutes bonding coat can be commercially available epoxy adhesive.

As mentioned above, polarization separating film can only form with first to the 3rd multilayer film (level number 2 to 43) and individual layer dielectric film (level number 44).In example 1, these films form polarization separating film with the middle refractive index film (level number 1 and 45) that inserts and puts usefulness.

As shown in Figure 1, the shape of cross section of each transparency carrier is trapezoidal, and first to the 3rd multilayer film is interposed between two transparency carriers.These trapezoidal base angles are set at 60 degree.Incident light LI is from a side directive transparency carrier 11 of transparency carrier, and incides on the polarization separating film in the modes of 60 degree incident angles.

Polarization beam apparatus according to example 1 has following structure.

As mentioned above, can in the wide visible wavelength range from 400nm to 750nm, realize good polarization separation function according to the polarization beam apparatus of the embodiment of the invention.As mentioned above, utilize the polarization beam apparatus of example 1, can realize very good polarization separation function.Particularly, incident angle is the incident light of 60 degree relatively, and in surpassing the 380nm and the wide wavelength coverage between the 780nm of visible wavelengths scope, the transmissivity of p polarization LP is 95% or bigger, and the transmissivity of S polarization LS is 0% substantially.

Function according to first to the 3rd multilayer film in the polarization beam apparatus of example 1 is described below.

Incident light LI is with incident angle directive first multilayer film of 60 degree.Thereby, the direction of propagation of transmittance first multilayer film relatively with first multilayer film in the thickness direction of each dielectric film tilt, thereby the actual range of transmission dielectric film is greater than actual thickness.The actual range of transmission dielectric film is called " the effective thickness of optics ".Obtain the effective thickness of optics in the following manner; The distance of transmission dielectric film is converted into the situation of the vertical directive film of light when light inclination directive film.

In first multilayer film, be 494/4nm about the effective thickness of the optics of high refractive index film, be 360/4nm about the optics net thickness of middle refractive index film.It is the polarization separation of the wavelength coverage at center that first multilayer film is responsible for 427nm, and 427nm is the mean value of two aforementioned thicknesses.

Similarly, in second multilayer film, be 672/4nm about the effective thickness of the optics of high refractive index film, be 490/4nm about the optics net thickness of middle refractive index film.It is being the polarization separation of the wavelength coverage at center with 581nm that second multilayer film is responsible for, and 581nm is the mean value of two aforementioned thicknesses.

In the 3rd multilayer film, be 761/4nm about the effective thickness of the optics of high refractive index film, be 555/4nm about the optics net thickness of middle refractive index film.It is being the polarization separation of the wavelength coverage at center with 658nm that the 3rd multilayer film is responsible for, and 658nm is the mean value of two aforementioned thicknesses.

So, carrying out with about 427nm by first multilayer film is the polarization separation of the wavelength coverage at center, by second multilayer film carry out with about 581nm be the center wavelength coverage polarization separation and be the polarization separation of the wavelength coverage at center by the execution of the 3rd multilayer film with about 658nm.In a word, can in the wavelength coverage between the 780nm, reach good polarization separation function at 380nm.

Fig. 2 shown when the light of wanting polarization separation with 60 the degree incident angle incident examples 1 shown in polarization beam apparatus the time the polarization separation function.Z-axis represents with % to be the transmissivity of unit, and transverse axis represents with nm to be the wavelength of unit.

In Fig. 2, with the transmissivity of the curve representation P polarization of reference marker 2-1 mark, it is 95% or bigger at the 380nm that exceeds visible wavelength range in the wavelength coverage of 800nm.With the transmissivity of the curve representation S polarization of reference marker 2-2 mark, it is 0% in theory, when being 0% at 380nm substantially in the wavelength coverage of 780nm.

As mentioned above, be the incident beam of design load 60 degree according to the polarization beam apparatus of example 1 about incident angle, in the wavelength coverage of 780nm, represented fabulous polarization separation function at the 380nm that exceeds visible wavelength range.Polarization separating film comprises 45 layers altogether, and it belongs to the smallest number rete; Particularly, 43 layers (level number 2 to 44) and individual layer dielectric film in first to the 3rd multilayer film, and the two-layer middle refractive index film (level number 1 and 45) that is folded in 43 interlayers.Transparency carrier is made by the low BK7 of inexpensive refractive index.The refractive index of the high refractive index film in the multilayer film is about 2.2.

So, adopt inexpensive material to be used for transparency carrier according to the polarization beam apparatus of example 1, and have the little rete of quantity (45 layers).Therefore, time and cost that deposition needs have been reduced.Therefore, this polarization beam apparatus can low-costly be made, and can represent good polarization separation function at wide visible wavelength range.

Fig. 3 A and Fig. 3 B have shown under the polarization beam apparatus situation that be designed into firing angle directive according to the present invention example 1 of the light beam of wanting polarization separation with 60 degree deviation ± 6 degree, the transmissivity of P polarization and S polarization.

In example 1, the shape of cross section of transparency carrier is trapezoidal, and each trapezoidal base angle is 60 degree.Light beam is to be designed into firing angle directive transparency carrier perpendicular to the mode on trapezoidal inclined-plane with 60 degree.Therefore, light beam directly extends to polarization separating film with 0 degree refraction angle directive incidence surface with 60 incident angles of spending.

When incident angle departs from 60 degree angle ± 6 when spending, incident angle departs from direction ± 6 degree on vertical trapezoidal inclined-plane.As a result, reflect at the relative transparency carrier of incidence surface.Therefore, at the departure degree of the incident angle of polarization separating film for departing from 60 degree ± 6 degree; Consider the refractive index (=1.52) of transparency carrier (BK7), the incident angle at the polarization separating film place departs from ± and 3.95.

In Fig. 3 A and Fig. 3 B, curve 2-1 and curve 2-2 represent respectively with the transmissivity (Fig. 3 A) of the P polarization of the incident angle of 60 degree and the transmissivity (Fig. 3 B) of S polarization.This is identical with curve 2-1 and 2-2 shown in Figure 2.In Fig. 3 A, curve 3-1 and 3-2 represent when the incident angle at polarization separating film it is the transmissivity of the P polarization of 56.05 degree and 63.95 when spending respectively.Is 80% or bigger at 350nm to the wavelength coverage internal transmission factor between the 800nm.In Fig. 3 B, curve 3-3 and 3-4 represent when the incident angle at polarization separating film it is the transmissivity of the S polarization of 56.05 degree and 63.95 when spending respectively.Substantially is 0% at 400nm to the wavelength coverage internal transmission factor between the 775nm.

As mentioned above, be 60 to compare when spending with incident angle, when incident angle departed from 60 degree ± 6 and spends, the polarization separation effect is variation slightly.But from actual aspect, this polarization separation effect is enough to be used in actual use.

When the polarization beam apparatus of example 1 is used for liquid crystal projection apparatus, after the light that light source sends becomes collimated light, can see slight direction scattering; Typically, light is to the scope inscattering at ± 4 degree.The polarization beam apparatus of example 1 can be allowed this scattering, because as mentioned above, even it has the polarization separation function that also is enough to be used in actual use when incident angle variation about ± 6 is spent.

In example 1, a pair of transparency carrier that inserts and puts polarization separating film is therebetween made by BK7.But the material of transparency carrier is not limited to BK7; This material can be to have refractive index to fall into optical glass in 1.46 to 1.58 scopes.In the distortion of example 1, first to the 3rd multilayer film, insert and put with in the refractive index film have identical refractive index with bonding coat, and optical glass is made by the optical glass with different refractivity.

＜variation 1 〉

In variation 1, transparency carrier has 1.48 refractive index (similar to example 1, the shape of cross section of transparency carrier is that the base angle is the trapezoidal of 60 degree, and incident angle is set at 60 degree).

Fig. 4 A has shown the transmissivity (curve 4-1) of the P polarization of variation 1 and the transmissivity (curve 4-2) of S polarization.The transmissivity of P polarization is 80% or bigger at 360nm in the wavelength coverage of 800nm, and the transmissivity of S polarization is 0% at 400nm in the wavelength coverage of 800nm substantially, and this shows good polarization separation function.

＜variation 2 〉

In variation 2, transparency carrier has 1.58 refractive index (similar to example 1, the shape of cross section of transparency carrier is that the base angle is the trapezoidal of 60 degree, and incident angle is set at 60 degree).

Fig. 4 B has shown the transmissivity (curve 4-3) of the P polarization of variation 2 and the transmissivity (curve 4-4) of S polarization.The transmissivity of P polarization is 80% or bigger at 350nm in the wavelength coverage of 800nm, and the transmissivity of S polarization is 0% at 350nm in the wavelength coverage of 750nm substantially, and this shows good polarization separation function.

In other variation of example 1, change the refractive index of the middle refractive index film in first to the 3rd multilayer film below.

＜variation 3 〉

In variation 3, middle refractive index film is (by Nb ₂O ₅And SiO ₂The film that potpourri is made) has 1.58 refractive index.

Fig. 5 A has shown the transmissivity (curve 5-1) of the P polarization of variation 3 and the transmissivity (curve 5-2) of S polarization.The transmissivity of P polarization is 85% or bigger at 350nm in the wavelength coverage of 800nm, and the transmissivity of S polarization is 0% at 380nm in the wavelength coverage of 780nm substantially, and this shows good polarization separation function.

＜variation 4 〉

In variation 4, middle refractive index film is (by Nb ₂O ₅And SiO ₂The film that is mixed and made into) has 1.72 refractive index.

Fig. 5 B has shown the transmissivity (5-3) of P polarization of variation 4 and the transmissivity (curve 5-4) of S polarization.The transmissivity of P polarization is 84% or bigger at 350nm in the wavelength coverage of 800nm, and the transmissivity of S polarization is below 5% at 420nm in the wavelength coverage of 780nm, and this has shown is enough to be used in the polarization separation of actual use function.

Each of the refractive index 1.58 of the middle refractive index film in the variation 3 and the refractive index 1.72 of the middle refractive index film in the variation 4 all is the central value at the 550nm wavelength.This value is at 610nm, and the practical center wavelength of 830nm and 940nm is respectively 1.572,1.553 and 1.546 in variation 3, be respectively 1.711,1.693 and 1.688 in variation 4.

In other variation of example 1, change the refractive index of the high refractive index film in first to the 3rd multilayer film below.

＜variation 5 〉

In variation 5, high refractive index film is (by Nb ₂O ₅The film of making) has 2.086 refractive indexes.

Fig. 6 A has shown the transmissivity (curve 6-1) of the P polarization of variation 5 and the transmissivity (curve 6-2) of S polarization.The transmissivity of P polarization is 95% or bigger at 350nm in the wavelength coverage of 800nm, and the transmissivity of S polarization is below 5% at 400nm in the wavelength coverage of 750nm, and this has shown is enough to be used in the polarization separation of actual use function.

＜variation 6 〉

In variation 6, high refractive index film is (by Nb ₂O ₅The film of making) has 2.336 refractive indexes.

Fig. 6 B has shown the transmissivity (curve 6-3) of the P polarization of variation 6 and the transmissivity (curve 6-4) of S polarization.The transmissivity of P polarization is 90% or bigger at 400nm in the wavelength coverage of 800nm, and the transmissivity of S polarization is 0% at 400nm in the wavelength coverage of 800nm substantially, and this has shown is enough to be used in the polarization separation of actual use function.

Each of the refractive index 2.086 of the high refractive index film in the variation 5 and the refractive index 2.336 of the high refractive index film in the variation 6 all is the central value at the 550nm wavelength.This value is at 610nm, and the practical center wavelength of 830nm and 940nm is respectively 2.063,2.020 and 2.009 in variation 5, be respectively 2.313,2.271 and 2.259 in variation 6.

In other variation of example 1, the structure of first to the 3rd multilayer film is identical with example 1 below, changes the refractive index of the middle refractive index film (level number 1 and 45) that inserts and puts usefulness.

＜variation 7 〉

In variation 7, insert and put with in the refractive index film (by Nb ₂O ₅And SiO ₂The film that is mixed and made into) has 1.555 refractive index.

Fig. 7 A has shown the transmissivity (curve 7-1) of the P polarization of variation 7 and the transmissivity (curve 7-2) of S polarization.The transmissivity of P polarization is 100% at 400nm in the wavelength coverage of 800nm substantially, and the transmissivity of S polarization is 0% at 400nm in the wavelength coverage of 780nm substantially, and this shows enough polarization separation functions.

＜variation 8 〉

In variation 8, insert and put with in the refractive index film (by Nb ₂O ₅And SiO ₂The film that is mixed and made into) has 1.65 refractive index.

Fig. 7 B has shown the transmissivity (curve 7-3) of the P polarization of variation 8 and the transmissivity (curve 7-4) of S polarization.The transmissivity of P polarization is 95% or bigger at 400nm in the wavelength coverage of 800nm substantially, and the transmissivity of S polarization is 0% at 390nm in the wavelength coverage of 780nm degree substantially, and this shows enough polarization separation functions.

The refractive index 1.555 that inserting and putting refractive index film in the usefulness in the variation 7 and each of the refractive index 1.65 that inserting and putting refractive index film in the usefulness in the variation 8 all are the central values at the 550nm wavelength.This value is at 610nm, and the practical center wavelength of 830nm and 940nm is respectively 1.547,1.527 and 1.521 in variation 7, be respectively 1.641,1.623 and 1.616 in variation 8.

As described in example 1 and variation 2 to 8, the transparency carrier that utilizes refractive index to fall in 1.48 to 1.58 scopes obtains good polarization separation characteristic, and the optical glass that utilizes refractive index to fall in 1.46 to 1.58 scopes obtains splendid effect.For example, in image display, if when transparency carrier has the refractive index that falls in 1.46 to 1.58 scopes, in 400nm arrives the wavelength coverage of 750nm, the transmissivity of P polarization is 80% or bigger substantially, and the transmissivity of S polarization is 0% substantially, so polarization beam apparatus is applicable.In first to the 3rd multilayer film, in refractive index is in 1.58 to 1.72 scopes when (in the value of wavelength 555nm) in the refractive index film have good polarization separation characteristic, high refractive index film has good polarization separation characteristic in the time of in refractive index is in 2.086 to 2.336 scopes, insert and put in the time of in refractive index is in 1.565 to 1.65 scopes with in the refractive index film have good polarization separation characteristic.

Below, the technical meaning of refractive index film during description inserts and puts and uses.

＜variation 9 〉

Example 1 comprises insert and put therebetween multilayer film insert and put with in refractive index film (level number 1 and 45) be not included in the polarization beam apparatus of variation 9.

Fig. 8 has shown the transmissivity (curve 8-1) of the P polarization of variation 9 and the transmissivity (curve 8-2) of S polarization.The transmissivity of P polarization is 95% or bigger at 380nm in the wavelength coverage of 800nm substantially, and the transmissivity of S polarization is 0% at 400nm in the wavelength coverage of 780nm substantially, and this shows enough polarization separation functions.But the polarization separation performance plot of comparison diagram 8 and Fig. 2 (example 1) can be found following difference.In example 1, the transmissivity of P polarization is 97% or bigger (Fig. 2) in the 800nm wavelength coverage at 380nm.In variation 9, the transmissivity of P polarization is trickle vibration in the scope that is centered on by the square-shaped frame among Fig. 8, that is, and and in 400nm arrives the wavelength coverage of 800nm.

This trickle vibration in the P polarization transmission rate becomes fluctuation.But,, can alleviate the fluctuation in the P polarization transmission rate by the refractive index film in the usefulness that inserts and puts that inserts and puts multilayer film therebetween is set.Although need not insert and put therebetween multilayer film insert and put with in the refractive index film polarization separation function that also can obtain to be enough to be used in actual use, by setting insert and put therebetween polarization separating film insert and put with in the refractive index film can further improve spectral-transmission favtor.

As mentioned above, in example 1, it is the polarization separation of the wavelength coverage at center that first multilayer film is responsible for 427nm, and it is the polarization separation of the wavelength coverage at center that second multilayer film is responsible for 581nm, and the 3rd multilayer film to be responsible for 658nm be the polarization separation of the wavelength coverage at center.

Polarization separation characteristic in an above situation using first to the 3rd multilayer film is described below.

At first, the only situation of first multilayer film of use-case 1 is described.

(being arranged in the substrate at top in the table 1) and being provided with corresponding level number 1 on the substrate of example 1 inserts and puts with refractive index film (central wavelength lambda 0=840nm, material: Nb ₂O ₅/ SiO ₂, refractive index 1.572, physics thickness: 133.60nm).First multilayer film of 14 layers that comprise corresponding instance 1 level number 2 to 15 is set at its top.Dielectric film is set as the individual layer dielectric film at its top, has structure identical and thickness (central wavelength lambda 0=610nm, material: Nb with the dielectric film of corresponding level number 2 ₂O ₅, refractive index 2.213, physics thickness: 68.90nm), thereby form 16 layers.Its top be provided with layer with level number 1 identical insert and put with in the refractive index film, thereby formation always has 17 layers polarization separating film.At last deposition insert and put with in the refractive index film adhere to another substrate (be positioned in the table 1 bottom substrate) with bonding coat.

According to table 1, table 2 has shown this structure.

(table 2)

Fig. 9 has shown the transmissivity (curve 9-1) of the P polarization in afore-mentioned and the transmissivity (curve 9-2) of S polarization.Obtain good polarization separation function in the wavelength coverage that with 427nm is the center.

The only situation of second multilayer film of use-case 1 is described below.

On the substrate of example 1, (be arranged in the substrate at top in the table 1) and be provided with inserting and putting of corresponding level number 1 with refractive index film (central wavelength lambda 0=840nm, material: Nb ₂O ₅/ SiO ₂, refractive index 1.572, physics thickness: 133.60nm).Second multilayer film of 14 layers that comprise corresponding instance 1 level number 16 to 29 is set at its top.Dielectric film is set as the individual layer dielectric film at its top, its dielectric film identical (central wavelength lambda 0=830nm, material: Nb with corresponding instance 1 level number 16 ₂O ₅, refractive index 2.170, physics thickness: 95.60nm), thereby form 16 layers.Its top be provided with layer with level number 1 identical insert and put with in the refractive index film, thereby formation always has 17 layers polarization separating film.At last deposition insert and put with in the refractive index film adhere to another substrate (be positioned in the table 1 bottom substrate) with bonding coat.

According to table 1, table 3 has shown this structure.

(table 3)

The layer of level number 16 to 29 in the layer corresponding instance 1 of level number 2 to 15 in the table 3.

Figure 10 has shown the transmissivity (curve 10-1) of the P polarization in afore-mentioned and the transmissivity (curve 10-2) of S polarization.Obtain good polarization separation function in the wavelength coverage that with 581nm is the center.

The only situation of the 3rd multilayer film of use-case 1 is described below.

On the substrate of example 1, (be arranged in the substrate at top in the table 1) and be provided with inserting and putting of corresponding level number 1 with refractive index film (central wavelength lambda 0=840nm, material: Nb ₂O ₅/ SiO ₂, refractive index 1.572, physics thickness: 133.60nm).The 3rd multilayer film of 14 layers that comprise corresponding instance 1 level number 30 to 43 is set at its top.Dielectric film is set as the individual layer dielectric film at its top, its dielectric film identical (central wavelength lambda 0=940nm, material: Nb with corresponding instance 1 level number 30 ₂O ₅, refractive index 2.159, physics thickness: 108.80nm), thereby form 16 layers.Its top be provided with layer with level number 1 identical insert and put with in the refractive index film, thereby formation always has 17 layers polarization separating film.At last deposition insert and put with in the refractive index film adhere to another substrate (be positioned in the table 1 bottom substrate) with bonding coat.

According to table 1, table 4 has shown this structure.

(table 4)

The layer of level number 30 to 43 in the layer corresponding instance 1 of level number 2 to 15 in the table 4.

Figure 11 has shown the transmissivity (curve 11-1) of the P polarization in afore-mentioned and the transmissivity (curve 11-2) of S polarization.Obtain good polarization separation function in the wavelength coverage that with 658nm is the center.

Variation 10 to example 1 distortion is described below.In variation 10, combine first and second multilayer films of example 1.

＜variation 10 〉

(being arranged in the substrate at top in the table 1) and being provided with corresponding level number 1 on the substrate of example 1 inserts and puts with refractive index film (central wavelength lambda 0=840nm, material: Nb ₂O ₅/ SiO ₂, refractive index 1.572, physics thickness: 133.60nm).First multilayer film of 14 layers that comprise corresponding instance 1 level number 2 to 15 is set at its top.Second multilayer film of 14 layers that comprise corresponding instance 1 level number 16 to 29 is set at its top.Dielectric film is set as the individual layer dielectric film at its top, its dielectric film identical (central wavelength lambda 0=830nm, material: Nb with corresponding level number 16 ₂O ₅, refractive index 2.170, physics thickness: 95.60nm), thereby form 30 layers.Its top be provided with layer with level number 1 identical insert and put with in the refractive index film, thereby formation always has 31 layers polarization separating film.At last deposition insert and put with in the refractive index film adhere to another substrate (be positioned in the table 1 bottom substrate) with bonding coat.

According to table 1, table 5 has shown this structure.

(table 5)

The layer of level number 2 to 29 in the layer corresponding instance 1 of level number 2 to 29 in the table 5.

Figure 12 has shown the transmissivity (curve 12-1) of the P polarization in afore-mentioned and the transmissivity (curve 12-2) of S polarization.P polarization transmission rate is 97% or bigger at 400nm in the 800nm wavelength coverage, and S polarization transmission rate is 0% at 400nm in the 650nm wavelength coverage substantially.Figure 12 has shown the product of the polarization separation characteristic of Fig. 9 and Figure 10.

In this case, the wavelength coverage that can carry out polarization separation be 400nm to 650nm, it slightly is narrower than the wavelength coverage of the 380nm of example 1 to 780nm.But, this wavelength coverage (400nm is to 650nm) covers visible wavelength range substantially, thereby also allows the actual use as polarization beam apparatus.

That is to say,,, just satisfy polarization beam apparatus according to the embodiment of the invention as variation 10 as long as comprise at least two dielectric multilayer films with different designs wavelength.

Fig. 9, the polarization separation characteristic of the example 1 that the product of the polarization separation characteristic of Figure 10 and Figure 11 is corresponding shown in Figure 2.

Situation in conjunction with the second and the 3rd multilayer film in the example 1 is described below.On the substrate of example 1, (be arranged in the substrate at top in the table 1) and be provided with inserting and putting of corresponding level number 1 with refractive index film (central wavelength lambda 0=840nm, material: Nb ₂O ₅/ SiO ₂, refractive index 1.572, physics thickness: 133.60nm).Second multilayer film of 14 layers that comprise corresponding instance 1 level number 16 to 29 is set at its top.The 3rd multilayer film of 14 layers that comprise corresponding instance 1 level number 30 to 43 is set at its top.Dielectric film is set as the individual layer dielectric film at its top, its dielectric film identical (central wavelength lambda 0=940nm, material: Nb with corresponding instance 1 level number 30 ₂O ₅, refractive index 2.159, physics thickness: 108.80nm), thereby form 30 layers.Its top be provided with layer with level number 1 identical insert and put with in the refractive index film, at last deposition insert and put with in the refractive index film adhere to another substrate (substrate bottom being positioned in the table 1) with bonding coat.

According to table 1, table 6 has shown this structure.

(table 6)

The layer of level number 16 to 43 in the layer corresponding instance 1 of level number 2 to 29 in the table 6.

As shown in figure 13, the product of corresponding Figure 10 of polarization separation characteristic in this case and polarization separation characteristic shown in Figure 11.In this case, P polarization transmission rate (curve 13-1) is good, but S polarization transmission rate (curve 13-2) becomes big at 400nm in the short wavelength range of 530nm.Therefore, the polarization separation function can not realize on whole visible wavelength range.But 530nm can obtain effective polarization separation function to the interior light of 780nm wavelength coverage relatively.Therefore, polarization beam apparatus is beneficial to as the polarization color filter that separates green color component from visible light.

And, be 8 to 20 according to the quantity of the laminate layers in each of the two or more dielectric multilayer films in the polarization separating film of the polarization beam apparatus of the embodiment of the invention, be preferably 12 to 16.In example 1 and above-mentioned its variation, the laminate layers quantity of the dielectric film in each dielectric multilayer film is 14.In variation 11, the laminate layers quantity of dielectric film is 12, and in variation 12, the laminate layers quantity of dielectric film is 10.

＜variation 11 〉

In variation 11, first multilayer film described in the example 1 has 12 layers of dielectric film of corresponding instance 1 level number 2 to 13.In variation 11, second multilayer film described in the example 1 has 12 layers of dielectric film of corresponding instance 1 level number 16 to 27.In variation 11, the 3rd multilayer film described in the example 1 has 12 layers of dielectric film of corresponding instance 1 level number 30 to 41.The dielectric film that corresponding instance 1 level number 44 is set at the top of the 3rd multilayer film is as individual layer dielectric film (identical with first dielectric film layer in the 3rd multilayer film, i.e. the dielectric film of level number 30).At its top, through corresponding instance 1 level number 45 insert and put with in refractive index film and bonding coat substrate is set.

Figure 14 has shown the transmissivity (curve 14-1) of the P polarization of variation 11 and the transmissivity (curve 14-2) of S polarization.The transmissivity of P polarization is 97% or bigger at 400nm in the wavelength coverage of 800nm, and the transmissivity of S polarization is 0% at 400nm in the wavelength coverage of 750nm substantially, and this has shown enough polarization separation functions of relative visible wavelength range.

＜variation 12 〉

In variation 12, first multilayer film described in the example 1 has 10 layers of dielectric film of corresponding instance 1 level number 2 to 11.In variation 12, second multilayer film described in the example 1 has 10 layers of dielectric film of corresponding instance 1 level number 16 to 25.In variation 12, the 3rd multilayer film described in the example 1 has 10 layers of dielectric film of corresponding instance 1 level number 30 to 39.The dielectric film that corresponding instance 1 level number 44 is set at the top of the 3rd multilayer film is as individual layer dielectric film (identical with first dielectric film layer in the 3rd multilayer film, i.e. the dielectric film of level number 30).At its top, through corresponding instance 1 level number 45 insert and put with in refractive index film and bonding coat substrate is set.

Figure 15 has shown the transmissivity (curve 15-1) of the P polarization of variation 12 and the transmissivity (curve 15-2) of S polarization.The transmissivity of P polarization is 97% or bigger at 400nm in the wavelength coverage of 800nm, and the transmissivity of S polarization is 0% at 400nm in the wavelength coverage of 750nm substantially, and this has shown enough polarization separation functions of relative visible wavelength range.By Figure 14 relatively and 15 clearly visible, when the laminate layers quantity in the multilayer film reduced, the transmissivity of S polarization (curve 15-2) can increase in by the short wavelength range of reference marker 15a mark and in by long wavelength's scope of the mark 15b mark among reference Figure 15.And, along with the minimizing of lamination number of plies amount in the multilayer film, can effectively use the wavelength coverage of polarization beam apparatus to narrow down.Be in actual use consideration in the visible wavelength range, the minimum number of laminate layers should be about 8.

When the polarization beam apparatus according to the embodiment of the invention was used for projector, the number of plies of each in first to the 3rd multilayer film preferably fell in 12 to 16 the scope, to satisfy following design conditions: incident angle is 60 degree; In the visible wavelength range of 700nm, the transmissivity of P polarization is 95% or bigger at 400nm, and the transmissivity of S polarization is less than 1%.

In example 1 and variation thereof, suppose in each dielectric multilayer film of corresponding different designs basis wavelength, to be provided with the laminate layers of equal number.And wavelength coverage is based on whole visible region (400nm is to 700nm).But, in being usually used in the extra-high-pressure mercury vapour lamp of projector, almost not smaller or equal to 420nm with more than or equal to any wavelength of 680nm.Therefore, in the research below, suppose effective wavelength range be 420nm to 680nm, the transmissivity of S polarization less than 5% (with as above-mentionedly have the situation of 8 laminate layers identical), the laminate layers of any amount can be arranged in each basic wavelength.Therefore, Ceng sum can further reduce.

The

variation

13 and 14 that describes below has such structure.

＜variation 13 〉

In the polarization beam apparatus according to variation 13, first multilayer film of example 1 has eight layers in variation 13, and second multilayer film of example 1 has six layers in variation 13, and the 3rd multilayer film of example 1 has four layers in variation 13.

According to table 1, table 7 has shown this structure.

(table 7)

Figure 17 is similar to Fig. 2, has shown the characteristic according to the polarization separation function of the polarization beam apparatus of variation 13.

In the characteristic of polarization separation function shown in Figure 17, in 420nm arrives the 680nm wavelength coverage, the transmissivity of P polarization (curve 17-1) is 98% or bigger (average 99% or bigger), the transmissivity of S polarization (curve 17-2) is (average below 1%) below 3%, and this has shown the characteristic that is enough to be used in actual use.

When first multilayer film comprises 8 layers, second multilayer film and the 3rd multilayer film add and comprise 10 layers together, the similar characteristic of polarization separation function shown in Figure 17.

If the laminate layers quantity in each multilayer film further reduces than variation 13, the performance of polarization beam apparatus can variation.The restriction that polarization beam apparatus stands exemplary application can change according to the needs specification of wanting using system.But, if the transmissivity of S polarization is about 10% (average about 3%) at 420nm in the wavelength coverage of 680nm, laminate layers quantity can be reduced to 6 layers in first multilayer film, add at the second and the 3rd multilayer film to be reduced to 8 layers (i.e. laminate layers quantity in second multilayer film and the laminate layers quantity in the 3rd multilayer film) together.

＜variation 14 〉

In the polarization beam apparatus according to variation 14, first multilayer film of example 1 has 6 layers in variation 14, and second multilayer film of example 1 has 6 layers in variation 14, and the 3rd multilayer film of example 1 has 2 layers in variation 14.

According to table 1, table 8 has shown this structure.

(table 8)

Figure 18 is also similar to Fig. 2, has shown the characteristic according to the polarization separation function of the polarization beam apparatus of variation 14.In the characteristic of polarization separation function shown in Figure 180, in 420nm arrives the 680nm wavelength coverage, the transmissivity of P polarization (curve 18-1) is 98% or bigger (average 99% or bigger), and the transmissivity of S polarization (curve 18-2) is 10% (average about 3%) to the maximum.

These values whether stand actual use depend on will with the spectral characteristic of lamp and whole optical system need specification.The situation that therefore, may have the discontented full border of the polarization separation function service condition of variation 13.Yet,, also can satisfy the condition of actual use even the polarization separation function of numeric ratio variation 14 is poor.

That is to say that in being applied to the polarization beam apparatus of certain system, this system comprises the restricted light source of wavelength coverage, as the LED that is used to throw light on, and does not need to obtain to run through the good characteristic of whole visible range.As long as correspondence will with the wavelength coverage of LED wavelength in to obtain good characteristic be exactly gratifying.Therefore, as long as can obtain the characteristic of good polarization separation function in the wavelength coverage of actual needs, actual just the use is not subjected to reduce the influence of laminate layers quantity in each multilayer film of polarization beam apparatus.

The reduction of cost is not the unique advantage that obtains by the laminate layers quantity that reduces in each stage construction of polarization beam apparatus.If absorb in the film of the multilayer film in being included in polarization beam apparatus, the characteristic of polarization beam apparatus will be because of this absorption variation.But by reducing lamination number of plies amount in each multilayer film, this variation will effectively be alleviated.

For example, at Nb as the middle refractive index film in the polarization beam apparatus that is included in according to the present invention example or variation ₂O ₅And SiO ₂Mixture layer in, can in relying on the particular range of wavelengths of acceptance condition, absorb.As a result, the characteristic variation of polarization beam apparatus.But, cause the quantity of the middle refractive index film of this absorption by minimizing, can alleviate the degree of individual features variation.

Figure 19 is relatively when absorb taking place, according to the characteristic (having 14 layers, 14 layers and 14 layers of combination) of the polarization beam apparatus of example 1 with according to the figure of the characteristic (having 8 layers, 6 layers and 4 layers of combination) of the polarization beam apparatus of variation 13.

As shown in figure 19, when not absorbing in the film, (when seeing in the drawings, be not positioned at left hand edge), in example 1 than in variation 13, obtain more substantial effective light.But (when seeing in the drawings, to the right), example 1 has shown than variation 13 is effectively having bigger consumption on the light quantity because the degree of absorption in the film increases.Therefore, when the absorption in the film increased to a certain degree, effective light quantity in the variation 13 was greater than example 1, thereby the performance advantage of these two examples will be conversely.Therefore as long as will use the required specification of system of polarization beam apparatus not have problems relatively, reduce that lamination number of plies amount is favourable in each multilayer film.Particularly, provide to comprise the multilayer film polarization beam apparatus cheaply, it can effectively alleviate by absorbing the polarization beam apparatus characteristic variation that causes in the film.

Clearly visible from Figure 17 and Figure 18, the performance of the transmissivity major decision polarization beam apparatus of S polarization.

Figure 20 A is the different relatively combinations that are included in the laminate layers quantity in each layer in first multilayer film to the, three multilayer films to Figure 20 F, the maximal value of mapping S polarization transmission rate (below be called " max value ").

To Figure 20 F, if the laminate layers quantity in first multilayer film is 8 layers or more (Figure 20 A is to Figure 20 D), select the suitable number of plies by in the second and the 3rd multilayer film each with reference to Figure 20 A, the maximal value of S polarization transmission rate is 5% or littler.But if first multilayer film has 6 layers, the maximal value of S polarization transmission rate is 10% to 15% (Figure 20 E).If first multilayer film has 4 layers, the maximal value of S polarization transmission rate will be above 15% (Figure 20 F).Consider that being restricted to of S polarization transmission rate 10% to 15% just can stand actual use.Therefore, the laminate layers quantity in first multilayer film is at least 6 layers.For obtaining higher performance, the laminate layers quantity in first multilayer film is for more than at least 8 layers.

About second multilayer film and the 3rd multilayer film, the laminate layers quantity in " second multilayer film+the 3rd multilayer film " is at least 6 layers (when first multilayer film comprises 6 layers or 8 layers respectively shown in Figure 20 E and Figure 20 D).For obtaining high-performance, the laminate layers quantity in " second multilayer film+the 3rd multilayer film " is at least 10 layers.When first multilayer film comprises 8 layers (Figure 20 D), can obtain 5% S polarization transmission rate, " second multilayer film+the 3rd multilayer film " comprises 8 layers (in second multilayer film 6 layers and the 3rd multilayer films 2 layers).For stably obtaining 5% or littler S polarization transmission rate, can consider in " second multilayer film+the 3rd multilayer film ", to comprise 10 layers.

So for obtaining to need other performance of level, the following setting of the minimum number of plies in each multilayer film: first multilayer film comprises 6 layers, " second multilayer film+the 3rd multilayer film " comprises 6 layers; Perhaps first multilayer film comprises 8 layers, and " second multilayer film+the 3rd multilayer film " comprises 10 layers.

To shown in the 20F, along with the increase of aforementioned lamination number of plies amount, performance will further strengthen as Figure 20 A.Therefore, the upper limit that does not have laminate layers in theory for the consideration of performance.But if very many laminate layers (as above 100 layers) are arranged, actual performance can be because of the absorption variation.For the purpose of practicality, be in the consideration of making efficient and cost, deposit required minimum lamination number of plies amount.Therefore, it is insignificant that the upper limit is set, and is significant and aforesaid lower limit is set.And the lower limit of laminate layers quantity is not limited to above-mentioned situation, because under actual environment, can have scrambling in equipment or material when sedimentary deposit.Therefore, in order stably to obtain desirable characteristics, need the degree of freedom that increases laminate layers quantity.

In example 1, insert and put refractive index film in the usefulness, first to the 3rd multilayer film and the monofilm transparency carrier 11 from Fig. 1 begins to form and lamination successively.Form at last insert and put with in refractive index film (level number 45) adhere to another transparency carrier by bonding coat (level number 46).Perhaps, can from another transparency carrier begin to form or the dielectric film of lamination example 1 (with begin from level number 45 to the order of level number 1), level number 1 insert and put with in the refractive index film adhere to top transparent substrate by bonding coat.

In this case, the dielectric film of corresponding instance 1 level number 44 to 31 is included in first multilayer film.The dielectric film of corresponding instance 1 level number 30 to 17 is included in second multilayer film.The dielectric film of corresponding instance 1 level number 16 to 3 is included in the 3rd multilayer film.The dielectric film of corresponding instance 1 level number 2 is as the individual layer dielectric film.

Figure 16 has shown the polarization conversion device according to the embodiment of the invention.

At the polarization conversion device shown in Figure 16 A is to be used to receive the incident light LI of natural light or random polarization attitude and to send the optical element with common polarization direction light.

Reference symbol IS represents incidence surface, incident light LI vertical incidence surface IS.Reference symbol OS expresses reflective surface.Incidence surface IS and exit surface OS are parallel to each other.

Part by reference marker 20 expressions is represented transparency carrier, reference letter M represents that polarization separating film (particularly, polarization separating film M comprises two or more at least dielectric multilayer films, individual layer dielectric film and bonding coat, they be sandwiched between described in example 1 and the variation 2 to 13 inserting and putting with between the refractive index film).

A plurality of polarization separating film M are equidistant mutually with parallel, thereby constitute the polarization separation membrane array.Each transparency carrier 20 is arranged between two adjacent polarization separating film M and by it to be shared.Particularly, each polarization separating film M upward forms by of being deposited in two transparency carriers 20 that insert and put polarization separating film M, and bonded layer adheres on another substrate 20.That is to say that the polarization separating film array that comprises polarization separating film M and be arranged on the transparency carrier 20 between the polarization separating film M forms wherein multilayer according to the structure of the polarization beam apparatus mutual superposition of above-mentioned arbitrary example, thereby forms in conjunction with monolithic entity.Particularly, the transparency carrier 20 that the surface segmentation that the edge is parallel to each other is shared is to form dividing surface, and the relative polarization separating film M of each dividing surface becomes 60 angle.This dividing surface is as incidence surface IS and exit surface OS.And when when seeing perpendicular to the direction of previous segmentation surface (incidence surface/exit surface) (when seeing in the drawings, being the direction from top and bottom portion), the polarization separating film M that is included in the polarization separation array closely arranges mutually.

When the polarization conversion device shown in incident light LI (being described as collimated light beam for the sake of simplicity) the directive figure, incident light LI incides on each polarization separating film M with the incident angle of 60 degree.Above-mentioned P polarized component is passed each polarization separating film M, becomes transmitted light beam LT.Simultaneously, the S polarized component is from each polarization separating film S reflection.The S polarized component transmission transparency carrier 20 of reflection, from adjacent polarization separating film M secondary reflection again, when seeing in the drawings, this adjacent polarization separating film M is near the right side of the polarization separating film M of S polarized component first reflection.Then, the S polarized component with the folded light beam LR that is parallel to transmitted light beam LT from exit surface OS outgoing.That is to say, from transmitted light beam LT and all edge direction propagation identical of folded light beam LR of exit surface OS outgoing with incident light LI.

On the exit surface OS of polarization conversion device, 1/2 equidistant wave plate 30 is set, each has along extending to rectangular shape perpendicular to the direction of figure.Each 1/2 wave plate 30 revolves around the polarizing coating of transmitted light beam LT and turn 90 degrees.

The width of each 1/2 wave plate 30 is half of adjacent polarization separating film M spacing among the figure.Because transmitted light beam LT transmission 1/2 wave plate 30, its plane of polarization revolves and turn 90 degrees.Therefore, the plane of polarization of transmitted light beam LT and direction identical (perpendicular to the direction of figure) from the folded light beam LR of polarization separating film M reflection.

In this way, as the incident light LI that incides on the polarization separating film M, the light of natural light or random polarization attitude is converted to the light beam of single polarization state.Light beam after the conversion is from the outgoing of polarization separation membrane array.

In the example shown in Figure 16 A, the polarizing coating of the transmitted light beam LT of transmission-polarizing diffusion barrier M is revolved by 1/2 wave plate 30 and turn 90 degrees; But, the invention is not restricted to this.Incide on 1/2 wave plate 30 from the folded light beam LR of polarization separating film M reflection, thereby its plane of polarization turn 90 degrees to revolve along the mode identical with the direction of transmitted light beam LT.

In above-mentioned example, the pitch angle of relative incidence surface/exit surface of polarization separating film M is 60 degree, the invention is not restricted to this.For example, the pitch angle can be the value near 60 degree that falls in 60 ± 6 degree scopes.

Figure 16 B has shown conventional polarization conversion device, and wherein relative incidence surface IS with reflectance coating R1 of polarization separating film M1 and exit surface OS inclination 45 degree, and alternately arrangement insert and put transparency carrier 21 therebetween.

Incide the incident light LI of polarization separating film M1,,, and be separated into transmitted light beam LT and folded light beam LR according to individual polarized component process polarization separation as the light of natural light or random polarization attitude.Folded light beam LR is from the reflectance coating R1 reflection adjacent with polarization separating film M1, and its plane of polarization turn 90 degrees to be revolved by 1/2 wave plate 30 along the mode identical with the direction of transmitted light beam LT.Therefore, the plane of polarization of outgoing beam is along identical direction.

The polarization conversion device according to the embodiment of the invention shown in conventional polarization conversion device shown in the comparison diagram 16B and Figure 16 A is according to the polarization conversion device of embodiment of the invention needs reflectance coating R1 not.Therefore,, thereby have simple structure, help making according to half of the transparency carrier laminate layers quantity of the conventional polarization conversion device of the polarization conversion device of an embodiment of the invention needs.

According to one embodiment of present invention, provide and be used for polarization separation polarization of incident light beam splitter.

When the incident angle of the light of wanting polarization separation falls into 54 when spending in the scopes of 66 degree, polarization beam apparatus works.

Generally, according to the Bu Lusaite condition, spend when 60 spend from 54 when incident angle and can obtain best polarization separation characteristic.Embodiments of the invention have effectively utilized this condition.That is to say about working, promptly to have good polarization separation characteristic with light near the ranges of incidence angles incident of Bu Lusaite condition according to the polarization beam apparatus of the embodiment of the invention.

When incident angle falls into 54 when spending in 66 degree scopes, polarization beam apparatus has good polarization separation characteristic.Therefore, when the incident light height collimated, incident light can be arranged to especially have and be fallen into 54 incident angles of spending in the 66 degree scopes.

And, consider in the incident light of directive polarization beam apparatus, to have small direction scattering.For example, if the scattering of incident angle in ± Δ θ scope, spread is 60 degree by the reference incident angle that is arranged so that directive polarization beam apparatus light in ± 6 degree, can realize good polarization separation function to the incident light of incident angle in 60 ± 6 degree scopes.

This polarization beam apparatus comprises a pair of transparency carrier, inserts and puts bonding coat between the transparency carrier, two or more dielectric multilayer films and individual layer dielectric film.

Bonding coat is used for adhering to first transparency carrier of two transparency carriers.

Two or more dielectric multilayer films have different designs basis wavelength.

Every kind of two or more dielectric multilayer films comprises high refractive index film and middle refractive index film, and each has the thickness according to respective design basis wavelength.High refractive index film and middle refractive index film alternatively laminated are to form even level.Because form the even number laminate layers in each dielectric film, a dielectric film that is positioned at each dielectric multilayer film end is a high refractive index film, and another is middle refractive index film.

The individual layer dielectric film is arranged on the bonding coat side that is positioned at the dielectric multilayer film on the bonding coat in two or more dielectric multilayer films.Individual layer dielectric film and the corresponding film identical (having identical structure and thickness) that is arranged on the ground floor (from from bonding coat dielectric film layer farthest) of the dielectric multilayer film on the bonding coat.

Two or more dielectric multilayer films and individual layer dielectric film form polarization separating film, and this polarization separating film comprises the light execution polarization separation function of visible wavelength region relatively substantially.

Remark additionally below, two or more dielectric multilayer films form by sequential aggradation and laminate layers on of two transparency carriers.The top of the dielectric multilayer film of Xing Chenging in the end, the deposited monolayers dielectric film.This individual layer dielectric film have with the corresponding last dielectric multilayer film that forms in the identical structure and the thickness of film of ground floor.

The shape of transparency carrier is a parallel substrate, but the invention is not restricted to this.The shape of transparency carrier can be that Dove prism or base angle are set at the Dove prism identical with incident angle.

The light of wanting polarization separation incides on the polarization separating film through inciding a transparency carrier that inserts and puts polarizing coating.Therefore, 54 degree come the directive incidence surface if incident angle for example is set at, this incidence surface is that incident has the side (inclined-plane) that the base angle is the transparency carrier of 60 trapezoidal cross-sections of spending, and spends less than 54 according to the reflective functions of transparency carrier in the incident angle of polarization separating film.

The high index of refraction of high refractive index film is usually the high index of refraction of definition, promptly more than or equal to 2.0.The middle refractive index of middle refractive index film falls in 1.56 to 1.78 scopes, and it is between the high index of refraction and common fixed middle refractive index of definition usually.

In two transparency carriers of light beam diffusion barrier, the optical glass that at least one dielectric multilayer film deposition second transparency carrier (for by the bonding transparency carrier of bonding coat) is thereon preferably fallen in 1.46 to 1.58 scopes by refractive index is made.

In the dielectric multilayer film with different designs basis wavelength, high refractive index film is by Nb ₂O ₅Make, middle refractive index film is by Nb ₂O ₅And SiO ₂Potpourri make.The refractive index of refractive index film is by Nb in having in each in the wavelength dielectric multilayer film on different designs basis ₂O ₅And SiO ₂The composite rate adjustment.And, have in the dielectric multilayer film of different designs basis wavelength each high refractive index film and in each the optical thickness of refractive index film can be set at λ/4 about the design basis wavelength X.

Laminate layers quantity in every kind of two or more dielectric multilayer films in the polarization beam apparatus falls in 8 to 20 scopes, preferably falls in 12 to 16 the scope.Consider the polarization separation function, laminate layers quantity can be greater than 20.But, comprise 20 or the dielectric multilayer film of more multi-layered number to form time of needs long, this has reduced the efficient of manufacturing polarization beam apparatus.Therefore, consider manufacturing cost, 20 layers is suitable quantity.

In above-mentioned polarization beam apparatus, two or more dielectric multilayer films and individual layer dielectric film be interposed in two insert and put with between the refractive index film.The refractive index film was preferably by Nb during each inserted and put and uses ₂O ₅And SiO ₂Potpourri make, have the refractive index of refractive index film in being different from the dielectric multilayer film.The optical thickness of refractive index film preferably was set at Λ/4 with respect to the wavelength Λ of the arbitrary design basis wavelength that is different from two or more dielectric multilayer films during each inserted and put and uses.

In above-mentioned polarization beam apparatus, three kinds of dielectric multilayer films and individual layer dielectric film are interposed between two transparency carriers.The design basis wavelength of three kinds of dielectric multilayer films can be set at λ 1=610[nm respectively], λ 2=830[nm] and λ 3=940[nm].Three kinds of dielectric multilayer films and individual layer dielectric film be sandwiched between insert and put with between the refractive index film.Define each wavelength X that inserts and puts refractive index film optical thickness in the usefulness and be preferably set to 840nm.

In above-mentioned polarization beam apparatus, have λ 1=610[nm], λ 2=830[nm] and λ 3=940[nm] every kind of three kinds of dielectric multilayer films of design basis wavelength has 14 laminate layers respectively.

In above-mentioned polarization beam apparatus, can change three kinds of numbers of plies in the dielectric multilayer film.If the number of plies is the design basis wavelength is λ 1=610[nm] dielectric multilayer film at least 6 layers and the design basis wavelength be λ 2=830[nm] dielectric multilayer film and design basis wavelength be λ 3=940[nm] dielectric multilayer film at least 6 layers the combination of adding up, can obtain to be used for the polarization separating film of actual use, decision design basis wavelength is λ 1=610[nm] dielectric multilayer film at least 8 layers and the design basis wavelength be λ 2=830[nm] dielectric multilayer film and design basis wavelength be λ 3=940[nm] dielectric multilayer film at least 10 layers the combination of adding up.

Each high refractive index film, the refractive index product of middle refractive index film and corresponding its film thickness (physical thickness) of the optical thickness that inserts and puts refractive index film in the usefulness and film component.

In above-mentioned polarization beam apparatus, high refractive index film is by Nb ₂O ₅Make, middle refractive index film is by Nb ₂O ₅And SiO ₂Potpourri make.By carrying out Nb reactive sputter-deposition high refractive index film.By carrying out refractive index film in Si reactive sputtering and the Nb reactive sputter-deposition simultaneously.

But carry out Si reactive sputtering and Nb reaction simultaneously when forming in the deposition refractive index film, can by regulate Si sputter intensity and Nb sputter intensity to make a gesture of measuring regulate in the refractive index of refractive index film.Nb ₂O ₅Has about 2.34 high index of refraction, SiO ₂Has about 1.43 low-refraction.

When carrying out Si reactive sputtering and Nb reactive sputtering simultaneously, reaction simultaneously produces SiO ₂And Nb ₂O ₅The component of deposited film becomes by Nb ₂O ₅And SiO ₂Potpourri constitutes.So, by regulate Si sputter intensity and Nb sputter intensity to making a gesture of measuring and control SiO as film component ₂And Nb ₂O ₅Mixing ratio can access the arbitrary refractive index between 1.43 to 2.34.

Middle refractive index film is adjusted to linearity and has middle refractive index (for example, about 1.56 to 1.75).So, with the mode that realizes refractive index in this design regulate Si sputter intensity and Nb sputter intensity to making a gesture of measuring.

Simultaneously, by Nb ₂O ₅The high refractive index film of making can be by the Nb that is produced by the Nb reactive sputtering ₂O ₅Nb with the deposition generation ₂O ₅Film forming forms.Utilize reactive sputtering, mainly produce Nb ₂O ₅But the material of generation is not 100% Nb ₂O ₅Meeting produces being different from of trace simultaneously but is similar to Nb ₂O ₅Material.

Therefore, the composition of the high refractive index film of actual deposition is not pure Nb ₂O ₅, but have a small amount of dissimilar material to mix.And the packed density of film is inhomogeneous.Therefore, by Nb ₂O ₅The refractive index of the high refractive index film of making changes in 2.07 to 2.34 scopes.But by regulating mode of deposition to obtain constant refractive index, the refractive index of high refractive index film can good repeatability be controlled in constant level.Therefore, this inhomogeneous material does not have adverse influence to high refractive index film.

In above-mentioned polarization beam apparatus, a pair of transparency carrier is made by BK7.

Polarization conversion device according to the embodiment of the invention comprises a plurality of any above-mentioned polarization beam apparatus with multiple layer (multiple tiers) stack, thereby forms the polarization separation array.Adjacent and parallel polarization separating film is shared public transparency carrier in the described transparency carrier.The transparency carrier of sharing is cut apart along the plane that is parallel to each other and is formed dividing surface, and the relative polarization separating film of each dividing surface becomes the angle of basic 60 degree.But when seeing perpendicular to the direction of dividing surface, the polarization separating film that is parallel to each other is closely contact or contiguous the setting mutually.The incident light of wanting polarization separation is from a cutting surface directive polarization separation membrane array as incidence surface.Incident light is separated into transmitted light and reflected light at each polarization separating film according to corresponding polarized component, reflected light is in the following manner from the polarization separating film reflection adjacent with this polarization separating film, that is, propagate along the direction identical with the incident light direction from another light as the dividing surface outgoing of exit surface.On the dividing surface of the exit surface of another conduct, be positioned at transmitted light or reflected light part from its outgoing, half-wave plate is set, thereby obtains light with single polarization state.

In above-mentioned polarization conversion device, when from incident direction and exit direction at least one seen, 60 degree that tilt of at least one in relative incidence surface of all polarization separating films and the exit surface, polarization separating film is provided with mutually in intimate contact.

The invention is not restricted to specifically described embodiment, can change without departing from the present invention and be out of shape.

The application is based on the Japan of submitting on Dec 28th, 2006 patented claim No.2006-356390 and Japan of submitting on October 12nd, 2007 patented claim No.2007-266540 formerly formerly, and its full content is incorporated instructions into as a reference.

Claims

1. one kind is used for polarization separation polarization of incident light beam splitter, wherein when the light of wanting polarization separation have fall into 54 spend in 66 degree scopes incident angle the time, this polarization beam apparatus works, this polarization beam apparatus comprises between two transparency carriers:

Be configured to adhere to the bonding coat of first transparency carrier in two transparency carriers;

Two or more have the dielectric multilayer film of different designs basis wavelength; And

The individual layer dielectric film, wherein:

The shape of cross section of described two transparency carriers is trapezoidal, and described trapezoidal base angle is 60 degree;

Every kind of two or more dielectric multilayer films comprises high refractive index film and the middle refractive index film that has according to the optical thickness of respective design basis wavelength, and described high refractive index film and middle refractive index film alternatively laminated are to form even level;

The individual layer dielectric film is set in place on the bonding coat side of the dielectric multilayer film on the bonding coat side, and this individual layer dielectric film and a film are of identical composition and thickness, and a described film is corresponding with the described ground floor that is arranged in the dielectric multilayer film on the bonding coat side;

Two or more dielectric multilayer films and individual layer dielectric film form polarization separating film, and this polarization separating film is in the light of visible wavelength region relatively substantially and carries out the polarization separation function;

Described two or more dielectric multilayer films and described individual layer dielectric film be sandwiched between two insert and put with between the refractive index film, each insert and put with in the refractive index film by Nb ₂O ₅And SiO ₂Potpourri make, and have with dielectric multilayer film in the different refractive index of middle refractive index film, each insert and put with in optical thickness of refractive index film be set at Λ/4 with respect to the wavelength Λ that is different from arbitrary described design basis wavelength;

Described insert and put with in the refractive index of refractive index film be in 1.565 to 1.65 the scope;

In two transparency carriers, at least the second transparency carrier is made by the optical glass that refractive index falls in 1.46 to 1.58 scopes, and this second transparency carrier deposits a dielectric multilayer film;

In the dielectric multilayer film with different designs basis wavelength, high refractive index film is by Nb ₂O ₅Make, middle refractive index film is by Nb ₂O ₅And SiO ₂Potpourri make;

The refractive index of refractive index film is by Nb in each ₂O ₅And SiO ₂Mixing ratio regulate; And

The optical thickness of each high refractive index film and middle refractive index film is set at λ/4 with respect to the design basis wavelength X.

2. polarization beam apparatus according to claim 1, wherein: every kind laminate layers quantity of described two or more dielectric multilayer films falls into 8 to 20 scope or 12 to 16 scope.

3. polarization beam apparatus according to claim 1, wherein:

Three kinds of dielectric multilayer films and individual layer dielectric film are sandwiched between between two transparency carriers;

The design basis wavelength of these three kinds of dielectric multilayer films is respectively λ 1=610[nm], λ 2=830[nm] and λ 3=940[nm].

4. polarization beam apparatus according to claim 3, wherein:

Described three kinds of dielectric multilayer films and described individual layer dielectric film be sandwiched between two insert and put with between the refractive index film, each insert and put with in the refractive index film by Nb ₂O ₅And SiO ₂Potpourri make, and have with dielectric multilayer film in the different refractive index of middle refractive index film, each insert and put with in optical thickness of refractive index film be set at Λ/4 with respect to the wavelength Λ that is different from arbitrary described design basis wavelength; And

Qualification insert and put with in each the wavelength Λ of optical thickness of refractive index film be set to 840nm.

5. polarization beam apparatus according to claim 3, wherein:

Have λ 1=610[nm respectively], λ 2=830[nm] and λ 3=940[nm] in three kinds of dielectric multilayer films of design basis wavelength every kind comprises 14 laminate layers.

6. polarization beam apparatus according to claim 3, wherein:

The number of plies of described three kinds of dielectric multilayer films is, have at least 6 laminate layers in the dielectric multilayer film of λ 1 design basis wavelength and have the dielectric multilayer film and combination of λ 2 design basis wavelength with at least 6 laminate layers of adding up in the dielectric multilayer film of λ 3 design basis wavelength, or, have at least 8 laminate layers in the dielectric multilayer film of λ 1 design basis wavelength and have the dielectric multilayer film and combination of λ 2 design basis wavelength with at least 10 laminate layers of adding up in the dielectric multilayer film of λ 3 design basis wavelength.

7. polarization beam apparatus according to claim 1, wherein:

The refractive index film is by carrying out the Si reactive sputtering simultaneously and the Nb reactive sputtering deposits in described; And

Described high refractive index film deposits by carrying out the Nb reactive sputtering.

8. polarization beam apparatus according to claim 1, wherein:

Described two transparency carriers are made by BK7.