WO2012126805A1

WO2012126805A1 - Projection of digital image data with a high light yield

Info

Publication number: WO2012126805A1
Application number: PCT/EP2012/054583
Authority: WO
Inventors: Michael Schulz-Grosser; Udo Schauss
Original assignee: Jos. Schneider Optische Werke Gmbh
Priority date: 2011-03-18
Filing date: 2012-03-15
Publication date: 2012-09-27
Also published as: DE102011014500A1

Abstract

The invention relates to a projection lens, which projects digital image data from two imaging units (102, 104) onto a projection screen (113). The light of the two imaging units (102, 104) is mutually perpendicularly polarised. The projection lens (106) has two identical first partial lenses (108, 110) which face the imaging units (102, 104), a second partial lens (112) which faces the screen (113), and a polarising beam combiner (200). The polarising beam combiner (200) is arranged between the first partial lens (108, 110) and the second partial lens (112). Each of the two first partial lenses (108, 110) forms a digital projection lens (106) together with the polarising beam combiner (200) and the second partial lens (112). In the process, the polarising beam combiner (200) combines the light (216, 218) of the two imaging units (102, 104) to form a common beam path (219), as a result of which an extremely high light yield is achieved.

Description

Projection of digital image data with high luminous efficacy

description

Field of the invention

The invention relates to a pro ektionsob ektiv for the projection of digital image data. Such lenses are mainly used in digital video technology for the projection of digitally recorded images in cinemas, in advertising or in presentations.

State of the art

In the projection of digital image data, digital electrical image signals are converted into optical information and projected onto a projection screen.

Important digital projection technologies include Liquid Crystal Display (LCD) technology and DLP technology (Digital Light Processing).

The DLP technology uses matrices from microelectromechanical mirror systems (Digital Mirror Device, DMD) which project or block incident light onto a projection screen through a projection lens, depending on the position of the individual mirror elements of the matrices. Conventional LCD pro ectors operate transmissively, ie an LCD is located in front of the proctor lamp and controls the light intensity.

Projectors with Liquid Crystal on Silicon (LCoS) technology work in a similar way to DLP devices. Instead of a chip with small mirrors, however, an LCD is used. This also reflects the light of the projector lamp on a screen. Contrast and black level correspond to those of the DLP projectors. In contrast to DMD chips, however, LCoS chips do not require any bars between the individual pixels, which results in a higher light output.

Since in the digital projection space-consuming optical elements such. B. a Strahlenvereiniger, be integrated between the image information source (LCD, LCoS, DLP chip) and ejjektobjektiv projective, projection lenses for the digital projection have a high cutting width. The

Cutting distance is defined here as the distance of the last object-side lens surface from the object-side focal plane.

The use of digital projection equipment, especially in public institutions and for advertising and cinema is constantly increasing and requires to improve the image quality for these purposes, an increasingly greater resolution of the projection lenses used here.

In order to obtain a sufficiently high-contrast image in this projection method, it is necessary that the projection objectives used for this purpose have a high modulation transfer function (MTF).

In addition, the lateral chromatic aberration (lateral chromatic

Aberration) should be as low as possible, ie points of different colors must be projected by the projection lens as much as possible in the same way. In addition, pro ective ective for digital projection using DMDs must have a largely object-side telecentric beam path. This is due to the fact that the beam combiner can only supply the lens with light below a certain critical angle. Even when projecting using a beam combiner, a certain angle must not be exceeded because the dichroic layers in the beam combiner otherwise cause a color shift (colorshading).

Obj ektseitige telecentricity means that the entrance pupil is almost at infinity. In other words, the main rays emanating from the points of the object (ie rays through the center of the entrance pupil) run parallel to the optical axis or do not exceed a certain tolerance angle.

In addition to the o. G. Requirements for the optical parameters of the projection lenses is a serious problem in the digital projection on large screens, the light output.

In particular, the LCD or LCoS projection media used in the digital projection are highly sensitive to temperature and therefore can not be loaded with arbitrarily high light output, which leads to a limitation of the brightness on the screen. task

The object of the invention is to significantly increase the luminous efficacy in the digital projection.

solution

This object is achieved by the invention with the features de: independent claims. Advantageous developments of the invention are characterized in the subclaims. The wording of all claims is hereby incorporated by reference to the stop this description. The invention also includes all reasonable and in particular all mentioned combinations of independent and / or dependent claims.

A projection objective for projecting digital image data from two imaging units onto a projection screen is proposed. The light of the two imaging units is polarized perpendicular to each other.

The proposed projection lens has the following elements:

a) two, the imaging units facing, identical first part lenses;

b) a second partial objective facing the projection screen, and

c) a polarizing beam combiner.

The polarizing beam combiner is disposed between the first sub-objective and the second sub-objective. Each of the two first part lenses, together with the polarizing beam combiner and the second part objective, form a digital projection objective, wherein the polarizing beam combiner combines the light of the two imaging units into a common beam path.

LCD and LCoS projectors radiate polarized light as a matter of principle. They can therefore serve as imaging units for the proposed projection objective.

In the projection objective according to the invention, the two partial lenses receive light from one projector / imaging unit each. The light of one projector must therefore be rotated in its direction of polarization by 90 ° with respect to the light of the other projector / the other imaging unit, so that it can be merged lossless with the polarizing Strahlenvereiniger with the light of the second projector. This almost leads to a doubling of the light output. The imaging units provide the (possibly digital) image content to be pro iced, ie they provide light that transports the image content. The projection objective according to the invention is capable of projecting the image contents of two imaging units. Each of the imaging units contains at least one projection medium.

The LCD or LCoS chips commonly used today as projection media basically provide polarized light. This can be a 1-chip, 2-chip or 3-chip project.

Each imaging unit can have either one projection medium or several, in particular three projection media. Typically, three projection media would be used for the three colors red, green and blue.

The structure of the proposed projection lens is suitable for both 1-chip and 3-chip projection in the imaging units.

In a 1-chip projection, the colors required for the colored projection are usually successively projected by a so-called color wheel or filter wheel. In a 3-chip project, one chip is used for the three colors red, green and blue. The three colors are then merged into one ray unit cube. For the proposed structure, this would be done for each of the two light entry channels.

The system is not suitable for the use of colored LED chips or a DMD, since these i. d. R. do not emit polarized light.

The light generation in the proposed solution can, as usual, for. B. be realized by lamps.

The term "projection objective" encompasses the combination of lenses and ray unit cubes The partial objectives are typically arranged at an angle of 90 ° to one another. net. In this case, all of the partial optics and the radiation unit cube are integrated into a common structural unit which has connecting surfaces for the imaging units.

The production media and any ray unit cubes belonging to the projection media are considered part of the projector / imaging unit.

The polarizing beam combiner expediently consists of two 90 ° prisms, which are each characterized by a refractive index nP. An interference layer system is arranged between the hypotenuse surfaces of the prisms, wherein in the interference layer system a layer of a material H with a refractive index nH> nP and a layer of a material L with a refractive index nL <nP follow one another alternately.

For connecting the two prisms and the interference layer system with each other, at least one layer of an optical cement having a refractive index nL <nKitt <nP <nH is provided.

In this case, the interference layer system is designed with the layer sequence, as stated in Table 4 below. The respective layer thickness is given in micrometers.

Layer code letter thickness

of [μπι]

material

1H0, 126190

2 L 0, 078320

3H0, 139240

4L 0, 100280

5H 0, 120280

6 L 0, 117210

7H 0, 121100

8 L 0, 134560

9 H 0, 039780

10 L 0, 183640

11 H 0, 042200

12 L 0, 234140

13 H 0, 027570 Layer code letter thickness

of [μπι]

material

14 L 0, 174280

15 H 0, 038340

16 L 0, 114910

17 H 0, 062870

18 L 0, 049640

19 H 0, 078490

20 L 0, 017000

21 H 0, 056480

Table 4

The material used for the interference layer system is preferably a material of low refractive index with a refractive index of 1.46 <nL <1.475, in particular quartz S1O ₂ , and as material H niobium pentoxide Nb ₂ Ü5 or titanium dioxide T1O ₂ with refractive index nH> 2.25.

The prisms consist of a glass having a refractive index of 1.7000 to 1.8000, in particular of 1.74950, and an Abbe number Vd of 25.0 to 55.0, in particular of 35.33, in particular of the glass with International Glass Code 750353 (trade name N-LAF7 from Schott and S-NBH51 from Ohara).

In the prior art, there are polarizing beam splitter cubes which could also be used as beam combiners in the reverse beam path, eg. MacNeille type (see, for example, US Pat. No. 2,403,731), which are characterized in that they transmit the parallel-oscillating light very well (Tp> 97%) and almost completely reflect the perpendicularly oscillating light (Rs> 99%). However, the acceptance angle is very small, d. H. the angle under the rays of light may enter, so that the function is given.

Recent developments show that there are also polarizing beam splitter cubes for a narrowband wavelength range, ie only for part of the visible light allow a higher acceptance angle (see, for example, DE 10 315 688 AI).

Compared to the beam splitter type MacNeille (see above), the proposed polarizing beam combiner has a much larger acceptance angle. In addition, he is broadband; it captures the entire visible spectral range.

The invention also includes a pro ektionssystem for projection of digital image data with the following components:

a) two imaging units, wherein the light of the two imaging units is polarized perpendicular to each other; and

b) a projection lens according to the structure described above.

Further details and features will become apparent from the following description of preferred embodiments in conjunction with the subclaims. In this case, the respective features can be implemented on their own or in combination with one another. The possibilities to solve the problem are not limited to the embodiments. For example, area information always includes all - not mentioned - intermediate values and all imaginable subintervals.

The embodiments are shown schematically in the figures. The same reference numerals in the individual figures designate the same or functionally identical or with respect to their functions corresponding elements. 1 shows a schematic representation of the basic optical structure of the projection system;

Fig. 2 is a schematic representation of the basic structure of the polarizing Strahlenvereinigers; 3 shows a schematic illustration of an exemplary embodiment of the principal lens arrangement of the projection objective with the two first and the second partial objective as well as an inserted polarizing one

Beam combiner;

Fig. 4 is a graph showing the course of the reflection of the p-light, plotted against the wavelength and field angle of the 43 mm objective; and

5 shows a graph of the course of the transmission of the s-light, plotted against the wavelength and the field angle of the 43 mm objective.

The technical data of three exemplary embodiments of the projection objective according to the schematic representation in FIG. 3 are listed in Tables 1 to 3. In detail shows:

Tab. 1 is a list of the radii, the thicknesses or air spacings, the refractive indices and the Abbe numbers of a first exemplary embodiment of the projection objective shown in FIG. 3;

Tab. 1A is a list of the aspheric coefficients of the first embodiment of the projection objective shown in FIG. 3;

Tab. 2 is a list of the radii, the thicknesses or air spacings, the refractive indices and the Abbe numbers of a second embodiment of the projection objective shown in FIG. 3;

Tab. 2A is a list of the aspheric coefficients of the second exemplary embodiment of the projection objective shown in FIG. 3;

Table 3 shows a list of the radii, the thicknesses or air spacings, the refractive indices and the Abbe numbers of a third exemplary embodiment of the e ective ective (not shown in the figures);

Tab. 3A is a list of the aspheric coefficients of the third embodiment of the projection lens.

1 shows a preferred exemplary embodiment of a projection system 100 in its basic structure, consisting of the projection objective 106 and two imaging units 102, 104. The projection objective 106 has two first partial objectives 108, 110 and a second partial objective 112. The two first partial lenses 108, 110 face the imaging units 102, 104, while the second partial objective 112 faces a projection screen 113. The imaging units also have a beam combiner 105, 107. The beam combiner 105 has a light exit surface 105a, a light entry surface 105b and a transparent plate 105c with a light entry surface 105d. The beam combiner 107 in the lateral beam path is configured identically.

In the projection lens 106 except the partial lenses

108, 110 and 112 nor a polarizing beam combiner 200 integrated. The polarizing beam combiner 200 is arranged in the air space between the two first partial lenses 108, 110 and the second partial lens 112.

The two first partial lenses 108, 110 are each arranged in front of an entrance surface of the polarizing Strahlenvereinigers 200 at an angle of 90 ° to each other. The optical structure of the two first partial lenses 108, 110, as well as their arrangement between the imaging units 102, 104 and the respective entry surfaces of the polarizing Strahlenvereinigers 200 match.

The basic structure of the described projection system 100 can be based on various cinema projection objective for digital projection. Projection lenses for digital projection usually have a telecentric structure, which is why they also have a large airspace in the middle of the lens or in the middle of the lens. This air space is suitable for incorporating the polarizing beam combiner cube 200 proposed here. As a result, starting from a known projection lens for digital cinema projection, on the one hand the beam unit cubes 200 described here can be installed in the large air space in the center of the objective 106, on the other hand it is possible to use the lens group 110 which is located between the beam unit cubes 200 and the imaging unit 104 are mounted with respect to the lens group 108 identically offset by 90 ° to provide the digital projection objective according to the invention.

The polarizing beam combiner 200 shown in FIG. 2 consists of two identical 90 ° prisms 202, 204 with a refractive index nP. The prisms consist of a glass with a refractive index of 1.7 to 1.8, in particular of 1.74950, and an Abbe number of 25.0 to 55.0, in particular of 35.33, and in particular from the glass with the international glass code 750353.

Between the hypotenuse surfaces 206, 208 of the two prisms 202, 204, an interference layer system 210 is arranged. The interference layer system 210 is evaporated on the hypotenuse surface 206 of the prism 202. In the interference layer system 210 are a total of 21 layers, namely layers of a material H with a refractive index nH> nP and layers of a material L with a refractive index nL <nP, alternately consecutive in the layer sequence 212 (from 1 to 21 according to Table 4 ) arranged. The connection of the two prisms 202, 204 and the interference layer system 210 with each other is realized by the layer 214 of an optical cement, which is arranged between the interference layer system 210 and the Hypotenusefläche 208 of the prism 204.

The incident laterally into the lens 106 light 216 defines together with the e ektionswand 113 towards running light a plane. Light whose polarization direction lies in this plane is referred to as being parallel polarized (p light), in this case light of the beam path 218. Light polarized perpendicular to this plane is referred to as s light, in this case light of the beam path 216.

The beam combiner cube 200 reflects the s-light 216 at its diagonal center plane 210 and transmits the p-light 218. In the embodiment shown in FIGS. 1 and 2, therefore, the straight-through light 218 is p-light or 90 ° Angle for this purpose in the lens 106 coupled light 216 s light. Both beam paths 216, 218 are thus combined with each other in beam splitter cube 200 to form beam path 219 and thus pass through second sub-objective 112 in the direction of projection screen 113.

For the definition of the polarization directions of the coupled partial beams 216, 218, there are several common possibilities. These include, for example, the use of a Lambda quarter plate. But it is just as possible, already at

Set up the LCD or LCoS projection media to set or set the polarization direction.

The optical arrangement shown in FIG. 3 as an exemplary embodiment of the proposed projection objective 106 has the following elements in the p-ray path 218, 219, viewed in the order from the projection wall 113, ie from left to right, in total: a first negative meniscus lens 304, the convex surface 302 facing the projection wall 113;

a second negative meniscus lens 310, the convex surface 308 facing the projection wall 113;

a third biconcave lens 316, the lower concave ones

Surface 314 of the projection screen 113 faces;

a fourth positive meniscus lens 322, the concave surface 320 facing the projection screen 113;

a fifth positive meniscus lens 328, the convex surface 326 facing the projection screen 113;

a sixth positive meniscus lens 334, the convex surface 332 facing the projection wall 113;

a seventh negative meniscus lens 340, the convex surface 338 facing the projection wall 113;

a combiner cube 200;

an eighth biconvex lens 350, the lower curved surface 348 facing the projection screen 113;

a ninth negative meniscus lens 356, the concave surface 352 facing the projection screen 113;

a tenth biconcave lens 362, the lower concave

Surface 360 of the projection screen 113 faces;

an eleventh biconvex lens 368 with its more domed surface 366 facing the projection screen 113; and

a twelfth biconvex lens 374, its more curved surface 372 facing the projection screen 113.

The eighth and ninth lenses 350, 356 are cemented together and form a doublet.

The first to seventh lenses are optical elements of the second partial objective 112, while the eighth to twelfth lenses are optical elements of the first partial objective 110 in the p-beam path 218.

The further first partial objective 108, which in the s-ray path 216 at an angle of 90 ° to the p-beam path 218th when viewed from the polarizing beam combiner 200, consists of the following lenses:

a biconvex lens 378,

a negative meniscus lens 380,

a biconcave lens 382,

a biconvex lens 384, and

a further biconvex lens 386.

The lens arrangement, the lens shapes and optical data of the lenses of the subobjective 108 in the s beam path are identical to those of the lenses of the sub-component 110 in the p beam path.

The precise details of the technical data, such as radii, thicknesses or air spacings, refractive indices and Abbe numbers, the lens arrangement shown schematically in Fig. 3, which form a suitable projection lens together with the polarizing beam combiner described in Fig. 2, can be found for three concrete embodiments in Tab. 1 to 3.

Table 1 shows the optical data of a projection lens 106 with a f-number of 2.5 and a focal length of 43 mm.

Table 2 shows the data of a projection lens 106 with a f-number of 2.5 and a focal length of 38 mm.

Table 3 lists the data (radii, thicknesses, refractive indices and Abbe numbers) of a third embodiment of the projection lens with a f-number of 2.5 and a focal length of 60 mm. The projection lens of this third example is not shown in the figures. It differs from the schematic structure of FIG. 3 in that the second partial objective 112 has only 6 lenses instead of seven lenses. The basic structure of Table 3 is analogous to Tables 1 and 2, but contains no reference numerals.

In Tables 1A and 2A, the respective aspherical data of the projection objectives 106 shown in Fig. 3 and Tables 1 and 2, respectively, are listed

- Table 1A for the lens with 43 mm focal length acc. Tab. 1, and

- Table 2A for the lens with 38 mm focal length acc. Tab. 2, together with the respective associated reference numerals.

Table 3A lists the aspherical data for the 60mm focal length projection objective as shown in Table 3. The abbreviations or coefficients are used in

Explained briefly below. The surface of an aspherical lens can be generally described by the following formula:

Z =

in which

z is the arrow height (in mm) with respect to the axis perpendicular

Plane, ie the direction of the deviation from the plane perpendicular to the optical axis, d. H. in the direction of the optical axis.

C indicates the so-called vertex curvature. It serves for

Description of the curvature of a convex or concave

Lens surface and is calculated from the reciprocal of the

Radius.

y indicates the distance from the optical axis (in mm), y is a radial coordinate. K indicates the so-called cone constant.

A ₂ , A, A ₆ , A ss, A _{10 represent} the so-called aspheric coefficients, which are the coefficients of a polynomial winding of the function describing the surface of the asphere.

Characteristics of the pro ektionsob ektivs with 43 mm focal length are shown graphically in Figures 4 and 5.

Fig. 4 shows for the 43 mm project ektionsobj ektiv a spatial representation of the graphical progression of the transmission 400 of the light in the p-beam at different field angles, while in Fig. 5 for this purpose, the graphic course of the reflection 500 of the light in the s-ray path will be shown.

The two progress graphics 400 and 500 illustrate that with the projection objective 106 according to the invention, an extremely high light output is realized with respect to the light passing through the second partial objective 112 in the direction of the projection wall 113 in the common beam path 219, this result being due to the excellent reflection or reflection. Transmissionsseigenschaften the polarizing Strahlenvereiniger- cube 200 is justified. One recognizes both the large spectral width or homogeneity, as well as the large acceptance angle.

There are numerous modifications and developments of the described embodiments be realized. So z. B. fertilize all measurements of thicknesses or distances or radii basically scalable for different focal lengths and applicators. Tab. 1

Focal length 43 mm / screen k

Reference ^¬ Radius Thickness or refractive index Abbe number sign [mm] Air distances n _d v _d

[Mm]

302,112,000

304 5, 500 1, 75520 27, 51

306 89, 801

14, 800 1, 00000

308 485, 556

310 6, 000 1, 43875 94, 99

312 79, 769

44, 830 1, 00000

314-1689, 191

316 6, 000 1, 49700 81, 54

318 72, 541

39, 000 1, 00000

320-346, 619

322 25, 000 1, 48749 70.41

324-77, 200

18, 750 1, 00000

326 45, 620

328 5, 300 1, 48749 70.41

330 45, 620

9, 000 1, 00000

332 64, 831

334 7, 450 1, 55836 54, 01

336 155, 029

24, 750 1, 00000

338 82, 975

340 5, 710 1, 43875 94, 99

* 342 31, 832

33, 700 1, 00000

220 INFINITE

200 40, 000 1, 61340 44, 27

205 INFINITE

21, 300 1, 00000

348,394,723

350 14, 570 1, 56907 71, 31

352-41,256

356 23, 340 1, 61336 44.49

358-68665

8, 370 1, 00000

360 -1689,191

362 4, 940 1, 61336 44.49

364 53,570 Reference ^¬ Radius Thickness or refractive index Abbe number sign [mm] Air distances n _d v _d

[Mm]

5, 140 1, 00000

366 61,551

368 15, 000 1, 43875 94, 99

370-165,829

0, 120 1, 00000

372 129,729

374 6, 000 1, 43875 94, 99

376-336,970

12, 000 1, 00000

105a INFINITE

105 116, 500 1, 51680 64, 17

105b INFINITE

105c 3, 000 1, 50847 61, 19

105d INFINITELY

* = aspherical surface

Tab. 1A

Tab. 2

Focal length 38 mm / aperture k

[Mm]

* 302 146, 891

304 6, 000 1, 59240 68, 36

306 72, 253

15, 000 1, 00000

308 359, 880

310 6, 000 1, 43875 94, 99

312 93, 513

44, 830 1, 00000

314-1689, 191

316 6, 000 1, 49700 81, 54

318 84, 636

39, 000 1, 00000

320-654, 855

322 25, 000 1, 48749 70.41

324-84, 969

18, 750 1, 00000

326 50, 849

328 5, 300 1, 48749 70.41

330 53, 802

7, 500 1, 00000

332 68, 600

334 7, 450 1, 55836 54, 01

336 133, 938

24, 750 1, 00000

338 71, 057

340 5, 710 1, 43875 94, 99

342 31, 832

* 342 31, 832 0, 010 1, 48749 70.41

33, 700 1, 00000

220 INFINITE

200 40, 000 1, 74950 35, 33

205 INFINITE

19, 300 1, 00000

348 1062, 002

350 14, 570 1, 56907 71, 31

352-43, 173

356 23, 340 1, 61336 44.49

358-67, 782

8, 370 1, 00000

360-748, 944 Reference ^¬ Radius Thickness or refractive index Abbe number sign [mm] Air distances n _d v _d

[Mm]

362 4, 940 1, 61336 44.49

364 56, 766

5, 200 1, 00000

366 65, 394

368 15, 000 1, 43875 94, 99

370 -150, 993

0, 120 1, 00000

372 105, 507

374 6, 300 1, 43875 94, 99

376-392, 46

12, 000 1, 00000

105a INFINITE

105 116, 500 1, 51680 64, 17

105b INFINITE

105c 3, 000 1, 50847 61, 19

* = aspherical surface

Tab. 2A

Tab. 3

Focal length 60 mm / aperture k = 2.5

Area Radius Thickness or refractive index Abbe number

[mm] Air gaps n _d v _d

[Mm]

1 237, 317

6, 000 1, 64769 33, 79

2 90, 543

13, 180 1, 00000

3,186,318

6, 000 1, 49700 81, 54

4 54, 651

26, 800 1, 00000

5 -40, 056

10, 000 1, 51680 64, 17

6 -44, 104

0, 100 1, 00000

7 1115, 641

9, 300 1, 55836 54, 01

8-102, 323

3, 500 1, 00000

9 44, 310

9, 450 1, 56883 55, 98

10 51, 682

33, 320 1, 00000

11 47, 582

5, 710 1, 49700 81, 54

* 12 29, 523

30, 000 1, 00000

13 INFINITE

40, 000 1, 74950 35, 33

14 INFINITE

16, 800 1, 00000

15-397, 918

15, 570 1, 5924068, 36

16-37, 215

21, 600 1, 61340 44, 27

17 -62, 044

11, 390 1, 00000

18 -1544, 914

4, 940 1, 61336 44.49

19 57, 232

5, 000 1, 00000

20 66, 183

11, 700 1, 43875 94, 99

21-170, 217 Area Radius Thickness or refractive index Abbe number

[mm] Air gaps n _d v _d

[Mm]

0, 120 1, 00000

22 87, 283

7, 700 1, 43875 94, 99

23-597, 029

12, 000 1, 00000

24 INFINITE

116, 500 1, 51680 64, 17

25 INFINITE

3, 000 1, 50847 61, 19

26 INFINITE

0, 000 1, 00000

* = aspherical surface

Tab. 3A

reference numeral

100 Pro ection system

102 imaging unit

104 imaging unit

105 ray unit of the imaging unit in the p-ray path

105a light exit surface of the Strahlenvereinigers

105b light entrance surface of the beam combiner / surface of the transparent plate 105c

105c transparent plate

105d light entrance surface of the transparent plate 105c

106 Proposal-related

107 Radiation unit of the imaging unit in the s-beam path

108 first partial objective in the s-beam path

110 first partial objective in the p-beam path

112 second partial lens

113 projection screen

200 polarizing beam combiner

202 first prism of the polarizing beam combiner

203 entrance surface of the first prism

204 second prism of the polarizing beam combiner

205 entrance surface of the second prism

206 hypotenuse surface of the prism 1 of the polarizing

Beam combiner unifier

208 hypotenuse surface of the prism 2 of the polarizing

Beam combiner unifier

Interference layer system between the hypotenuse surfaces of the prisms of the polarizing beam combiner (layer sequence from 1 to 21)

212 Direction of the defined layer sequence (from 1 to 21) 214 layer of optical cement

216 s beam path

218 p-ray path

219 common beam path

220 exit surface of the first prism

302 first surface of the lens 304

304 first lens (negative meniscus lens) of the second part

Obj ektivs

306 second surface of the lens 304

308 first surface of the lens 310

310 second lens (negative meniscus lens) of the second part

Obj ektivs

312 second surface of the lens 310

314 first surface of the lens 316

316 third lens (biconvex lens) of the second part

Obj ektivs

318 second surface of the lens 316

320 first surface of the lens 322

322 fourth lens (positive meniscus lens) of the second part

Obj ektivs

324 second surface of the lens 322nd

326 first surface of the lens 328

328 fifth lens (positive meniscus lens) of the second part

Obj ektivs

330 second surface of the lens 328

332 first surface of the lens 334

334 sixth lens (positive meniscus lens) of the second

Partial obj ective

336 second surface of the lens 334

338 first surface of the lens 340

340 seventh lens (negative meniscus lens) of the second

Partial obj ective

342 second surface of the lens 340 348 first surface of the lens 350

350 first lens of the first partial ektivs 110th

352 second surface of the lens 350 / first surface of the

Lens 356

356 second lens of the first part-ektivs 110th

358 second surface of the lens 356

360 first surface of the lens 362

362 third lens of the first partial lens 110

364 second surface of the lens 362

366 first surface of the lens 368

368 fourth lens of the partial lens 110

370 second surface of the lens 368

372 first surface of the lens 374

374 fifth lens of the first sub-objective 110

376 second surface of the lens 374

378 first lens of the first partial objective 108 in the s

Beam path (viewed from the polarizing beam combiner)

380 second lens of the first partial lens 108 in the s

Beam path (viewed from the polarizing beam combiner)

382 third lens of the first partial objective 108 in the s

Beam path (viewed from the polarizing beam combiner)

384 fourth lens of the first partial objective 108 in the s

Beam path (viewed from the polarizing beam combiner)

386 fifth lens of the first partial objective 108 in the s

Beam path (viewed from the polarizing beam combiner)

400 graphical progression of the transmission of the light in the p

beam path graphical course of the reflection of the light in the s

beam path

cited literature cited patent literature

DE 10 315 688 A1

US 2,403,731

Claims

claims

1. Pro ektionsob ektiv (106) for projecting digital image data from two imaging units 102, 104 on a projection screen (113),

wherein the light of the two imaging units (102, 104) is polarized perpendicular to each other,

wherein the projection objective (106) has the following elements:

a) two, the imaging units (102, 104) facing, identical first part lenses (108, 110);

b) a second partial objective (112) facing the screen (113);

c) a polarizing beam combiner (200);

d) wherein the polarizing beam combiner (200) between the first partial lenses (108, 110) and the second

Partial lens (112) is arranged;

e) wherein each of the first two partial lenses (108, 110) together with the polarizing beam combiner (200) and the second partial lens (112) form a digital projection lens (106); and

f) wherein the polarizing beam combiner (200) combines the light (216, 218) of the two imaging units (102, 104) into a common beam path (219).

2. projection lens (106) according to the preceding claim,

characterized,

that the polarizing beam combiner (200)

a) two 90 ° prisms (202, 204) with a refractive index nP and b) an interference layer system (210) arranged between the hypotenuse surfaces (206, 208) of the prisms (202, 204) having,

c) wherein in the interference layer system (210) a layer of a material H with a refractive index nH> nP and a layer of a material L with a refractive index nL <nP follow one another alternately, and

d) for the connection of the two prisms (202, 204) and the interference layer system (210) together at least one layer (214) of an optical cement having a refractive index nL <nKitt <nP <nH is provided;

e) wherein the interference layer system (210) is designed with the layer sequence as set out in the table below, wherein the respective layer thickness is given in micrometers:

Layer code letter layer thickness

of [μπι]

material

1H0, 126190

2 L 0, 078320

3H0, 139240

4L 0, 100280

5H 0, 120280

6 L 0, 117210

7H 0, 121100

8 L 0, 134560

9 H 0, 039780

10 L 0, 183640

11 H 0, 042200

12 L 0, 234140

13 H 0, 027570

14 L 0, 174280

15 H 0, 038340

16 L 0, 114910

17 H 0, 062870

18 L 0, 049640

19 H 0, 078490

20 L 0, 017000

21 H 0, 056480 f) wherein as material L a material having a refractive index of 1.46 <nL <1.475, in particular quartz S1O ₂ , and as material H niobium pentoxide Nb ₂ Ü5 or titanium dioxide T1O _{2 are provided} with the refractive index nH> 2.25.

3. Pro ektion system (100) for the projection of digital image data with the following components:

a) two imaging units (102, 104), wherein the light (216, 218) of the two imaging units (102, 104) is polarized perpendicular to each other; and

b) a projection lens (106) according to one of the preceding claims.