• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    The present invention relates to an imaging system comprising at least one laser light source with a wavelength in the visible spectral range and a beam guidance element with high resistance to solarization at high beam power densities. The invention also relates to the use of the imaging system, in particular in projectors and in material processing.
    公开号:BE1028287B1
    申请号:E20215381
    申请日:2021-05-12
    公开日:2022-03-04
    发明作者:Sebastian Leukel；Volker Hagemann；Peter Nass；Uwe Petzold；Ralf Jedamzik
    申请人:Schott Ag；
    IPC主号:
    专利说明:

    ! The present invention relates to an imaging system comprising at least one laser light source with a wavelength in the visible spectral range and a beam guiding element with high solarization resistance at high beam power densities. The invention also relates to the use of the imaging system, particularly in projectors and in material processing. US 2018/0136446 A1 discloses a TIRF microscope (TIRF: English for “fota/internal reflection fluorescence”). US 5,925,468 A discloses an optical device combining a UV blocking glass and a solarization resistant glass. Light sources for projectors are currently undergoing a change from xenon to laser phosphors and pure RGB laser sources with constantly increasing luminous flux and power densities. Today's cinema projectors with laser sources, for example, achieve a luminous flux of up to
    75,000 lumens and areal power densities of up to 50 W/em or more. With increasing luminous flux and power density, the thermal load on optical components increases, which impairs the quality of the projection and the long-term stability. The optical system of a cinema projector usually consists of a large-volume prism arrangement and a projection lens. The prism arrangement in particular is exposed to high thermal stress. The demands on optical glasses with regard to low absorption losses, ie maximum transmission and low tendency to solarization, ie low induced absorption losses in use, are therefore constantly increasing. Traditional xenon-based cinema projectors have a maximum luminous flux of up to 45,000 lumens. In modern laser-based projectors, however, luminous fluxes of up to 75,000 lumen and surface power densities of up to 50 W/cm or more achieved. A strong blue laser excites the emission of yellow light in a converter. The green and yellow channels are extracted from the yellow light using dichroic filters. Part of the blue light is used for the blue channel. All three channels are then used for the projection. The projection system often consists of a complex array of prisms to direct the individual color channels to the DLP chips and mix the signals to form the image. The optical path length can be greater than 100 to 200 mm. Any light absorption within the prism assembly will result in temperature gradients and thermal lensing. The prism glass should therefore have the highest possible transmission in the visible wavelength range. Solarization effects in the glass are other effects that are becoming increasingly important as the luminous flux of the projectors increases. Absorption-induced generation of
    Defect centers in the prism glass can lead to a reduction in transmission, which in turn is associated with thermal lens effects.
    However, such solarization effects are not only relevant in the optical systems of modern projectors. Such phenomena also play an increasing role in applications in material processing.
    It is therefore an object of the present invention to provide imaging systems with beam guidance elements that have high solarization resistance in the visible spectral range, particularly in the blue spectral range, and can therefore be used excellently in projectors, but also in applications in material processing.
    Imaging systems are, in particular, systems with at least one light source and at least one beam guidance element, in particular lenses, prisms, aspheres and/or fiber optic rods. Such fiber optic rods use total reflection at the glass-air boundary and typically have a length of no more than 300 mm. Such imaging systems are used, for example, in projectors, in particular in cinema projectors. In this connection, an imaging system ensures that an image that the observer can see, for example on a screen, is generated by means of targeted beam guidance of the light from the light source. The highest power densities usually occur in the prisms, especially in prisms that mix the color channels. It is therefore particularly important to provide such prism beam guidance elements from materials that can withstand these power densities without relevant solarization effects occurring. Imaging systems are also used in material processing. Through targeted beam guidance, the light from the light source can be focused on the material to be processed in such a way that the energy input of the light radiation can be used for material processing.
    The object is solved by the subject matter of the patent claims. The object is achieved in particular by an imaging system comprising a) at least one laser light source selected from the group consisting of a laser light source B with a wavelength As in the spectral range of 380 nm to 490 nm, a laser light source G with a wavelength As in the spectral range of > 490 nm to 585 nm and a laser light source R with a wavelength Ar in the spectral range of > 585 nm to 750 nm, and b) a beam guiding element, wherein the laser light source is suitable, in at least one point of the beam guiding element, an average areal power density of more than 10 W /cm and the beam guiding element consists of a glass with a quality factor F(436 nm) = S(436 nm)*(Exto(436 nm) + Ext: (436 nm))/k, where F(436 nm) < 700 ppm/W.
    The imaging system according to the invention can include further components, for example imaging chips (in particular DLP chips) and/or projection optics.
    The imaging system according to the invention can include a laser light source B with a wavelength As in the spectral range from 380 nm to 490 nm. The imaging system preferably comprises a laser light source B with a wavelength Às in the spectral range from 400 nm to 480 nm, more preferably from 420 nm to 470 nm, more preferably from 425 nm to 460 nm, more preferably from 430 nm to 450 nm The imaging system according to the invention can include a laser light source G with a wavelength Ac in the spectral range from >490 nm to 585 nm. The imaging system preferably comprises a laser light source G with a wavelength As in the spectral range from 510 nm to 580 nm, more preferably from 520 nm to 570 nm, more preferably from 530 nm to 560 nm, more preferably from 540 nm to 550 nm The imaging system according to the invention can include a laser light source R with a wavelength Ar in the spectral range from >585 nm to 750 nm. The imaging system preferably comprises a laser light source R with a wavelength λr in the spectral range from 600 nm to 720 nm, more preferably from 610 nm to 700 nm, more preferably from 620 nm to 680 nm, more preferably from 630 nm to 660 nm preferably from 640 nm to 650 nm. The imaging system according to the invention can have exactly one laser light source selected from the group consisting of a laser light source B with a wavelength Às in the spectral range from 380 nm to 490 nm, a laser light source G with a wavelength Ac in the spectral range of > 490 nm to 585 nm and a laser light source R with a wavelength Ar in the spectral range from >585 nm to 750 nm. According to the invention, for example, imaging systems that have only one laser light source B with a wavelength As in the spectral range from 380 nm to 490 nm, or only one laser light source G with a wavelength As in the spectral range from >490 nm to 585 nm or only one laser light source R with a wavelength Ar in the spectral range from >585 nm to 750 nm.
    In other embodiments, the imaging system according to the invention can have exactly two laser light sources selected from the group consisting of a laser light source B with a wavelength Às in the spectral range from 380 nm to 490 nm, a laser light source G with a wavelength Ac in the spectral range from > 490 nm to 585 nm and one Laser light source R with a wavelength Ar in the spectral range from > 585 nm to 750 nm include. According to the invention, for example, imaging systems that have exactly one laser light source B with a wavelength Às in the spectral range from 380 nm to 490 nm and exactly one laser light source G with a wavelength Ac in the spectral range from > 490 nm to 585 nm, but no laser light source R with a wavelength Ar in the spectral range from> 585 nm to 750 nm. According to the invention are also imaging systems that have exactly one laser light source B with a wavelength As in the spectral range from 380 nm to 490 nm and exactly one laser light source R with a wavelength Ar in the spectral range from >585 nm to 750 nm, but no laser light source G a wavelength Ac in the spectral range from > 490 nm to 585 nm. Also according to the invention are imaging systems that have exactly one laser light source R with a wavelength Ar in the spectral range from >585 nm to 750 nm and exactly one laser light source G with a wavelength As in the spectral range from >490 nm to 585 nm, but no laser light source B with a Wavelength Às in the spectral range from 380 nm to 490 nm.
    The imaging system according to the invention particularly preferably comprises exactly three laser light sources selected from the group consisting of a laser light source B with a wavelength As in the spectral range from 380 nm to 490 nm, a laser light source G with a wavelength Ac in the spectral range of >490 nm to 585 nm and a laser light source R with a wavelength Ar in the spectral range from> 585 nm to 750 nm a wavelength Às in the spectral range from > 490 nm to 585 nm and a laser light source R with a wavelength Ar in the spectral range from > 585 nm to 750 nm.
    The laser light source B with a wavelength As in the spectral range from 380 nm to 490 nm, the laser light source G with a wavelength Ac in the spectral range from > 490 nm to 585 nm and/or the laser light source R with a wavelength Ar in the spectral range from > 585 nm to 750 nm nm is suitable, in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm, more preferably at least 0.5 cm, more preferably at least 1 cm, more preferably at least 2 cm, more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guiding element has an average areal power density of more than 10 Wem to create. The laser light source is preferred (in particular the laser light source B with a wavelength Às in the spectral range from 380 nm to 490 nm, the laser light source G with a wavelength Ac in the spectral range from > 490 nm to 585 nm and/or the laser light source R with a wavelength Ar in the spectral range from> 585 nm to 750 nm) suitable in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm”, more preferably at least 0.5 cm”, more preferably at least 1 cm”, more preferably at least 2 cm”, more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element has an average areal power density of more than 10 W/cm to 75 W/cm”, more preferably from 15 W/cm to 60 W/cm , more preferably from 20 W/cm up to 50 W/cm2, for example 25 W/m up to 45 W/cm or 30 W/cm up to 40 W/cm to create.
    The laser light source B is preferably suitable in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm, more preferably at least 0.5 cm, more preferably at least 1 cm, more preferably at least 2 cm. , more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element has an average surface power
    > BE2021/5381 density greater than 10 W/cm to create. More preferably, the laser light source B is suitable in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm, more preferably at least 0.5 cm, more preferably at least 1 cm, more preferably at least 2 cm ”, more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element an average areal power density of more than 10 W/cm to 75 W/cm , more preferably from 15 W/cm to 60 W/cm , more preferably from 20 W/cm up to 50 W/cm , for example 25 W/cm2 up to 45 W/cm or 30 W/cm up to 40 W/cm to create.
    The laser light source G is preferably suitable in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm², more preferably at least 0.5 cm”, more preferably at least 1 cm”, more preferably at least 2 cm”. , more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element an average areal power density of more than 10 W/cm to create. More preferably, the laser light source G is suitable in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm, more preferably at least 0.5 cm, more preferably at least 1 cm, more preferably at least 2 cm ”, more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element an average areal power density of more than 10 W/cm to 75 W/cm”, more preferably from 15 W/cm to 60 W/cm , more preferably from 20 W/cm up to 50 W/cm , for example 25 W/cm2 up to 45 W/cm or 30 W/cm up to 40 W/cm to create.
    The laser light source R is preferably suitable in at least one point of the beam guidance element, preferably on an area of at least 0.1 cm, more preferably at least 0.5 cm, more preferably at least 1 cm, more preferably at least 2 cm. , more preferably at least 3 cm”, more preferably at least 5 cm , more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element an average areal power density of more than 10 W/cm to create. More preferably, the laser light source R is suitable in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm, more preferably at least 0.5 cm, more preferably at least 1 cm, more preferably at least 2 cm ”, more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element an average areal power density of more than 10 W/cm to 75 W/cm , more preferably from 15 W/cm to 60 W/cm , more preferably from 20 W/cm up to 50 W/cm , for example 25 W/cm up to 45 W/cm or 30 W/cm up to 40 W/cm to create.
    The laser light source B, the laser light source G and the laser light source R are preferably suitable in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm, more preferably at least 0.5 cm, more preferably at least 1 cm ”,
    more preferably at least 2 cm”, more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element an average areal power density of more than 10 W/cm The laser light source B, the laser light source G and the laser light source R are more preferably suitable in at least one point of the beam guidance element, preferably on a surface of at least 0.1 cm, more preferably at least 0.5 cm , more preferably at least 1 cm”, more preferably at least 2 cm”, more preferably at least 3 cm”, more preferably at least 5 cm”, more preferably at least 7 cm”, more preferably at least 9 cm of the beam guidance element an average areal power density of more than 10 Wm to 75 W/cm”, more preferably from 15 W/m to 60 W/cm2, more preferably from 20 W/cm up to 50 W/cm , for example 25 W/cm up to 45 W/cm or 30 W/cm to 40 W/cm The imaging system according to the invention comprises a beam guidance element which consists of a glass which has a quality factor F(436 nm)=S(436 nm)*(Exto(436 nm)+Ext:(436 nm))/k , where F(436 nm) < 700 ppm/W. Under the irradiation of energetic photons in the UV range, defects are induced in materials, which lead to changes in the spectral transmission. If these are in the visible spectral range, this is accompanied by undesired color changes. This phenomenon is particularly undesirable for glass optical components. Surprisingly, it has now been shown that at high laser power densities, defect centers can also be induced in the visible spectral range, e.g. at 450 nm (=solarization), as is only the case with conventional light sources if they emit in the UV/NUV. Without being restricted to a specific explanation, it is assumed here that the occurrence of solarization effects when irradiated with visible light can be attributed in particular to non-linear effects associated with the high power densities. With excitation with sufficient power density, two-photon absorption could occur, which corresponds to the energy of a photon at half the wavelength (e.g. 450 nm / 2 = 225 nm) and thus corresponds to UV absorption. In contrast to conventional UV solarization, this effect is generally not limited to a volume of the glass near the surface facing the light source, but can take place along the entire length of the optical path. The defect centers formed induce new absorption bands that reduce the transmitted intensity. The induced absorption bands are accompanied by an increase in temperature within the optical material/glass; Since the refractive index and the geometric path change with temperature, the wavefront is delayed and undesirable imaging errors occur.
    This results in particularly high demands on the material of beam guidance elements that are used in imaging systems that include laser light sources that are suitable for an average surface power in at least one point of the beam guidance element.
    density of more than 10 W/cm to create. One object of the present invention is therefore to provide imaging systems that avoid or at least greatly reduce unwanted imaging errors.
    An exemplary embodiment of an imaging system of the present invention is shown schematically in FIG. According to this embodiment, the imaging system is a DLP projector. The term "DLP" is an abbreviation for the English term "Digital Light Processing". The imaging system according to the invention shown in Figure 1 comprises a laser light source 1 and a beam guiding element 2. According to the invention, the imaging system comprises at least one laser light source selected from the group consisting of a laser light source B with a wavelength As in the spectral range from 380 nm to 490 nm, a Laser light source G with a wavelength Ac in the spectral range from > 490 nm to 585 nm and a laser light source R with a wavelength Ar in the spectral range from > 585 nm to 750 nm. It is therefore also possible that more than one of the laser light sources mentioned is present in the imaging system according to the invention, in particular a blue laser light source, a green laser light source and a red laser light source. The laser light source 1, shown for simplification as a single box in FIG. 1, can represent, for example, three differently colored diode lasers, in particular a blue diode laser, a green diode laser and a red diode laser. It is also possible that only a single laser light source is present, for example a blue laser light source. In some embodiments, with the aid of a converter, in particular a ceramic converter, blue light emitted by a blue laser light source can be converted via luminescence into light with a longer wavelength, for example into yellow, green, red and/or yellow-green light.
    In the DLP projector shown in FIG. 1, the laser light source 1 emits blue, green and red light (shown by the arrow 5). This can be achieved, for example, in that the laser light source 1 represents the presence of a blue, a green and a red diode laser. It is also possible that only a blue laser is present and the additionally emitted green and red light is generated by the use of converter material. The three colors 5 emitted by the laser light source 1 reach the beam guiding element 2 after leaving the laser light source 1. The beam guiding element 2 comprises at least one prism and can also represent a prism arrangement comprising several prisms, for example. A prism arrangement can consist of two or three prisms, for example. The arrow 6 shows that the beam guidance element 2 deflects the light of the three colors emitted by the laser light source 1 onto imaging chips 3 . The light of each of the three colors (blue, green and red) is preferably deflected onto an imaging chip 3 each.
    For the sake of simplicity, only a single box, which represents the imaging chips 3, is shown in FIG. Preferred imaging chips 3 are DLP chips 3. The imaging system preferably includes an imaging chip 3 for each color channel. The case shown in Figure 1
    ten therefore preferably represents three imaging chips 3 (one each for blue, green and red), in particular three DLP chips 3.
    The images generated by the DLP chips 3 (in particular an image each in blue, green and red) then reach the beam guidance element 2 , in particular the prism 2 or the prism arrangement 2 . This is shown by the arrow 7 .
    The beam guidance element 2 then ensures that a composite color image reaches the projection optics 4 . This is shown by arrow 8.
    Very high surface power densities can occur, particularly in the area of the beam guidance element 2 . It is therefore important that the beam guidance element 2 consists of a glass which has a quality factor according to the invention.
    The object is achieved in particular in that the beam guidance element consists of a glass that has a quality factor F(436 nm) = S(436 nm)*(Exto(436 nm) + Ext:(436 nm))/k, where F (436 nm) is < 700 ppm/W.
    The quality factor F takes various factors into account which, in the combination found here, lead to a reduction in imaging errors. Both wavelength-dependent and wavelength-independent factors are taken into account. The quality factor F(436nm) at a wavelength of 436 nm is representative of the behavior of the glass in the spectral range from 380 nm to 490 nm. This range in turn is representative of the behavior of the glass in the entire visible spectral range. According to the invention, F(436 nm)<700 ppm/W applies.
    The behavior of the glass at wavelengths outside the range from 380 nm to 490 nm can in some cases, albeit to a lesser extent, contribute to aberrations. In principle, the figure of merit F(436 nm) is sufficient to describe the quality of the glass. ses. In certain cases, however, it can make sense to analyze not only the behavior of the glass at a wavelength of 436 nm but also its behavior at a wavelength of 546 nm, which is representative of the wavelength range from > 490 nm to 585 nm, and/or at a wavelength of 644 nm, which is representative of the wavelength range from > 585 nm to 750 nm. The beam guidance element preferably consists of a glass which has a quality factor F(546 nm)=S(546 nm)*(Exto(546 nm)+Ext:(546 nm))/k, where F(546 nm)< 215 ppm/W, and/or which has a figure of merit F(644 nm) = S(644 nm)*(Exto(644 nm) + Ext; (644 nm))/k, where F(644 nm) < 85 ppm/W is.
    A quality factor F(RGB) can be determined from the behavior of the glass at 436 nm, 546 nm and 644 nm. The beam guidance element preferably consists of a glass which has a quality factor F(RGB)=F(436 nm)+F(546 nm)+F(644 nm)=S(436 nm)*(Exto(436 nm)+Ext:( 436nm))/k + S(546nm)*(Exto(546nm) + Ext:(546nm))/k + S(644nm)*(Exto(644nm) + Ext:(844nm)) /k, where F(RGB) < 1000 ppm/W.
    The figure of merit F takes into account the thermality S(A), the non-induced extinction Exto(A), the induced extinction Ext:() and the thermal conductivity k of the glass. thermality, non-
    BE2021/5381 induced absorbance and induced absorbance are wavelength dependent quantities.
    The thermal conductivity is independent of the wavelength.
    The non-induced extinction Exto(A) can serve as a measure of the extinction in the as-delivered condition or before the intended use.
    The induced extinction Ext:(A) can be used as a measure for the
    appropriate operation serve potentially induced extinction.
    According to the invention, F(436 nm)<700 ppm/W applies.
    F(436 nm) is preferably at most 600 ppm/W, more preferably at most 500 ppm/W, more preferably at most 400 ppm/W, more preferably at most 350 ppm/W, more preferably at most 300 ppm/W, more preferably at most - at least 275 ppm/W, more preferably at most 250 ppm/W, more preferably at most 225 ppm/W, more preferably at most 210 ppm/W, more preferably at most 200 ppm/W, more preferably at most 150 ppm/W, further preferably at most 100 ppm/W, more preferably at most 75 ppm/W, more preferably at most 50 ppm/W, more preferably at most 25 ppm/W, more preferably at most 20 ppm/W, more preferably at most 15 ppm/W, more preferably at most 10ppm/W.
    In some embodiments, F(436 nm) is at least 0.1 ppm/W, at least 0.5 ppm/W, at least 1 ppm/W, or at least 2 ppm/W.
    F(546 nm)<215 ppm/W preferably applies.
    More preferably F(546 nm) is at most 200 ppm/W, more preferably at most 175 ppm/W, more preferably at most 150 ppm/W, more preferably at most 125 ppm/W, more preferably at most 100 ppm/W, more preferably at most 90 ppm/W, more preferably at most 80 ppm/W, more preferably at most 70 ppm/W, more preferably at most 60 ppm/W, more preferably at most 50 ppm/W, more preferably at most 40 ppm/W, more preferably at most 30 ppm/W, more preferably at most 20 ppm/W, more preferably at most 15 ppm/W, more preferably at most 10 ppm/W, more preferably at most 8 ppm/W, more preferably at most 6 ppm/W, more preferably at most at least 5 ppm/W.
    In some embodiments, F(546 nm) is at least 0.001 ppm/W, at least 0.005 ppm/W, at least 0.01 ppm/W, at least 0.02 ppm/W, at least 0.1 ppm/W, at least 0.5 ppm /W or at least 1 ppm/W.
    F(644 nm)<85 ppm/W preferably applies.
    More preferably, F(644 nm) is at most 80 ppm/W, more preferably at most 75 ppm/W, more preferably at most 70 ppm/W, more preferably at most 65 ppm/W, more preferably at most 60 ppm/W, more preferably at most 55 ppm/W, more preferably at most 50 ppm/W, more preferably at most 45 ppm/W, more preferably at most 40 ppm/W, more preferably at most 35 ppm/W, more preferably at most 30 ppm/W, more preferably at most 25 ppm/ W, more preferably not more than 20 ppm/W, more preferably not more than 15 ppm/W, more preferably not more than 10 ppm/W, more preferably not more than 8 ppm/W, more preferably not more than 6 ppm/W, more preferably not more than 5 ppm/W W
    In some embodiments, F(546 nm) is at least 0.001 ppm/W, at least 0.005 ppm/W, at least 0.01 ppm/W, or at least 0.02 ppm/W, at least 0.1 ppm/W, at least 0.5 ppm /W or at least 1 ppm/W.
    The beam guidance element therefore preferably consists of a glass which has a quality factor F(RGB)=F(436 nm)+F(546 nm)+F(644 nm)=S(436 nm)*(Exto(436 nm)+Ext: (436nm))/k + S(546nm)*(Exto(546nm) + Ext:(546nm))/k + S(644nm)*(Exto(644nm) + Ext:(644nm) )/k, where F(RGB) < 1000 ppm/W. Preferably F(RGB) is at most 900 ppm/W, more preferably at most 800 ppm/W, more preferably at most 700 ppm/W, more preferably at most 600 ppm/W, more preferably at most 500 ppm/W, more preferably at most 400 ppm/W W, more preferably at most 350 ppm/W, more preferably at most 300 ppm/W, more preferably at most 250 ppm/W, more preferably at most 200 ppm/W, more preferably at most 150 ppm/W, more preferably at most 100 ppm/W W, more preferably at most 80 ppm/W, more preferably at most 60 ppm/W, more preferably at most 50 ppm/W, more preferably at most 40 ppm/W, more preferably at most 30 ppm/W, more preferably at most 25 ppm/ W, more preferably at most 20 ppm/W. In some embodiments, F(RGB) is at least 0.5 ppm/W, at least 1 ppm/W, at least 2 ppm/W, or at least 5 ppm/W.
    A variable that has a significant influence on the quality factor F is the wavelength-dependent thermality S(A). Thermality describes the relative change in the optical path s = (n-1)*d with temperature T, where n is the refractive index and d is the sample thickness. The following applies: S =1/s*ds/dT. Since both d=d(T) and n=n(T) we have: S=1/s * (dn/dT*d + (n-1) dd/dT). Accordingly, S=1/(n-1)*dn/dT + 1/d*dd/dT=1/(n-1)*dn/dT + CTE. The CTE is the thermal expansion coefficient or thermal expansion coefficient (English: "coefficient of thermal expansion").
    The coefficient of thermal expansion is preferably determined as described under DIN 51045-1:2005-08 and DIN ISO 7991 1998-02. A glass sample of defined length is prepared and the relative change in length (DeltaL/L) per temperature interval (Delta T) is measured in a dilatometer. For the calculation of the thermality S(), the average coefficient of thermal expansion in a temperature range from -30°C to +70°C is preferably used. A low coefficient of thermal expansion is advantageous, particularly in a temperature range from -30°C to 70°C (CTE (-30/70)). The CTE (−30/70) is preferably in a range from 3.0 to 14.0 ppm/K, in particular from 4.0 to 10.0 ppm/K, from 4.5 to 9.5 ppm/K K, from 5.0 to 8.0 ppm/K, and/or from 5.5 to 7.5 ppm/K, for example from 5.6 to 7.3 ppm/K or from 5.7 to 7.2 ppm/K
    The determination of dn/dT can be done with a prism spectrometer (with a whole prism) placed in a temperature chamber. Measurement is preferred in a configuration in which the total deflection angle is minimal, since the refractive index can then only be calculated from the deflection angle and the known prism angle.
    However, dn/dT is particularly preferably determined using the half-prism method. To do this, the sample is placed in the form of a half prism in a temperature-controlled sample chamber.
    Il BE2021/5381 The prism is irradiated with light of different wavelengths and the deflection angle is determined in each case.
    The temperature in the chamber is varied.
    This gives the refractive index as a function of wavelength and temperature.
    The average dn/dT in a temperature range from +20°C to +40°C is preferably used to calculate the thermality S(A).
    In order to keep the extent of thermal lens effects as small as possible, it is advantageous if the change in the refractive index with temperature (dn/dT) is as small as possible, in particular within a temperature range of 20.degree. C. to 40.degree.
    The mean dn/dT at a wavelength of 436 nm, 546 nm and/or 644 nm in a temperature range from 20° C. to 40° C. is preferably in a range from 0.1 to 8.0 ppm/K, in particular from 0.2 to 7.0 ppm/K, from 0.3 to 6.0 ppm/K and/or from 0.4 to 5.0 ppm/K, the details relating to the absolute value (amount) of the mean obtain dn/dT.
    As described above, the induced absorption bands are accompanied by an increase in temperature within the glass, resulting in a wavefront delay and undesirable aberrations when the refractive index and geometric path change with temperature.
    The change in the optical path with temperature (the thermality S) is therefore preferably small.
    In this way, imaging errors can be minimized even if induced absorption bands occur.
    S(436 nm) is preferably at most 50 ppm/K, more preferably at most 30 ppm/K, more preferably at most 25 ppm/K, more preferably at most 20 ppm/K, more preferably at most 15 ppm/K, more preferably at most 10 ppm/K.
    In some embodiments, S(436 nm) is at least 0.1 ppm/K, at least 0.5 ppm/K, at least 1 ppm/K, or at least 2 ppm/K.
    S(546 nm) is preferably at most 50 ppm/K, more preferably at most 30 ppm/K, more preferably at most 25 ppm/K, more preferably at most 20 ppm/K, more preferably at most 15 ppm/K, more preferably at most 10 ppm/K.
    In some embodiments, S(546 nm) is at least 0.1 ppm/K, at least 0.5 ppm/K, at least 1 ppm/K, or at least 2 ppm/K.
    S(644 nm) is preferably at most 50 ppm/K, more preferably at most 30 ppm/K, more preferably at most 25 ppm/K, more preferably at most 20 ppm/K, more preferably at most 15 ppm/K, more preferably at most 10 ppm/K.
    In some embodiments, S(644 nm) is at least 0.1 ppm/K, at least 0.5 ppm/K, at least 1 ppm/K, or at least 2 ppm/K.
    S(436 nm), S(546 nm) and S(644 nm) are preferably at most 50 ppm/K, more preferably at most 30 ppm/K, more preferably at most 25 ppm/K, more preferably at most 20 ppm/K , more preferably at most 15 ppm/K, more preferably at most 10 ppm/K.
    In some embodiments, S(436 nm), S(546 nm), and S(644 nm) are at least 0.1 ppm/K, at least 0.5 ppm/K, at least 1 ppm/K, or at least 2 ppm/K .
    Other important quantities are the non-induced extinction Exto and the induced extinction Ext. Ext:() describes the (compared to Exto(A)) additional extinction per cm at the wavelength À after irradiation of the sample. The induced extinction Ext: depends, among other things, on the type of radiation source. A test with a high-pressure mercury lamp (HOK 4) has proven to be advantageous for evaluating materials with regard to their solarization stability. According to the invention, the induced extinction Ext:(A) describes the (compared to Exto(A)) additional extinction per cm at the wavelength À of a sample with a sample thickness d of 10 mm after irradiation with a HOK 4 lamp for 15 hours. In contrast, the non-induced extinction Exto() describes the extinction per cm at the wavelength À of a sample with a sample thickness d of 10 mm before irradiation. A HOK 4/120 lamp from Philips is preferably used. The spectrum of this HOK 4/120 lamp is shown in FIG. The distance between the lamp and the sample is 7 cm. The power density is preferably 25 mW/cm². The sample size is preferably 20 mm x 30 mm x 10 mm. As already described above, the dimension of 10 mm is referred to as sample thickness d.
    It is advantageous if Exto and Ext: are small. The sum of both values thus contributes to the quality factor F.
    A low non-induced extinction Exto is advantageous because there is a low initial extinction without previous irradiation with the HOK 4 lamp.
    A low induced extinction Ext: is also advantageous. It indicates that there is no excessive extinction even after irradiation and is therefore a measure of the solarization resistance.
    The extinction Ext(A) is calculated as the quotient of the natural logarithm of the quotient of incident radiation lo and exiting radiation | the wavelength À as the dividend and the sample thickness d as the divisor: Ext(A) = In(lo/l)/d. In this way, both Exto and Ext; to be determined. As already described above, the sample thickness d is 10 mm according to the invention.
    Exto(436 nm) is preferably less than 0.01/cm, more preferably at most 0.008/cm, more preferably at most 0.005/cm, more preferably at most 0.004/cm, more preferably at most 0.003/cm, more preferably at most 0.002/cm. In some embodiments, Exto(436 nm) is at least 0.0001/cm, at least 0.0002/cm, at least 0.0003/cm, or at least 0.0005/cm.
    Exto(546 nm) is preferably less than 0.01/cm, more preferably at most 0.008/cm, more preferably at most 0.005/cm, more preferably at most 0.004/cm, more preferably at most 0.003/cm, more preferably at most 0.002/cm, more preferably less than 0.0015/cm, more preferably less than 0.001/cm. In some embodiments
    Exto(546 nm) at least 0.0001/cm, at least 0.0002/cm, at least 0.0003/cm or at least 0.0005/cm. Exto(0.44 nm) is preferably less than 0.01/cm, more preferably at most 0.008/cm, more preferably at most 0.005/cm, more preferably at most 0.004/cm, more preferably at most 0.003/cm, more preferably at most 0.002/cm, more preferably less than 0.0015/cm. In some embodiments, Exto(644 nm) is at least 0.0001/cm, at least 0.0002/cm, at least 0.0003/cm, or at least 0.0005/cm. Exto(436 nm), Exto(546 nm) and Exto(644 nm) are preferably less than 0.01/cm, more preferably at most 0.008/cm, more preferably at most 0.005/cm, more preferably at most 0.004/cm, more preferably at most 0.003/cm, more preferably at most 0.002/cm. In some embodiments, Exto(436nm), Exto(546nm), and Exto(644nm) are at least 0.0001/cm, at least 0.0002/cm, at least 0.0003/cm, or at least 0.0005/cm. Ext:(436 nm) is preferably less than 0.3/cm, more preferably at most 0.2/cm, more preferably at most 0.1/cm, more preferably at most 0.08/cm, more preferably at most 0.06/cm cm, more preferably at most 0.04/cm, more preferably at most 0.02/cm, more preferably at most 0.01/cm, more preferably at most 0.009/cm, more preferably at most 0.008/cm, more preferably at most 0.007/cm cm, more preferably at most 0.006/cm. In some embodiments, Ext:(436 nm) is at least 0.0005/cm, at least 0.001/cm, at least 0.0015/cm, or at least 0.02/cm.
    Ext:(546 nm) is preferably less than 0.3/cm, more preferably at most 0.2/cm, more preferably at most 0.1/cm, more preferably at most 0.08/cm, more preferably at most 0.06/cm cm, more preferably at most 0.04/cm, more preferably at most 0.02/cm, more preferably at most 0.01/cm, more preferably at most 0.009/cm, more preferably at most 0.008/cm, more preferably at most 0.007/cm cm, further preferably at most 0.006/cm, further preferably at most 0.005/cm, further preferably at most 0.004/cm, further preferably at most 0.003/cm. In some embodiments, Ext:(546 nm) is at least 0.0001/cm, at least 0.0002/cm, at least 0.0003/cm, or at least 0.0005/cm.
    Ext:(644 nm) is preferably less than 0.3/cm, more preferably at most 0.2/cm, more preferably at most 0.1/cm, more preferably at most 0.08/cm, more preferably at most 0.06/cm cm, more preferably at most 0.04/cm, more preferably at most 0.02/cm, more preferably at most 0.01/cm, more preferably at most 0.009/cm, more preferably at most 0.008/cm, more preferably at most 0.007/cm cm, further preferably at most 0.006/cm, further preferably at most 0.005/cm, further preferably at most 0.004/cm, further preferably at most 0.003/cm. In some embodiments, Ext:(644 nm) is at least 0.0001/cm, at least 0.0002/cm, at least 0.0003/cm, or at least 0.0005/cm.
    Preferably, Ext:(436 nm), Ext:(546 nm) and Ext:(644 nm) are less than 0.3/cm, more preferably at most 0.2/cm, more preferably at most 0.1/cm, more preferably at most
    0.08/cm, more preferably at most 0.06/cm, more preferably at most 0.04/cm, more preferably at most 0.02/cm, more preferably at most 0.01/cm, more preferably at most 0.009/cm , more preferably at most 0.008/cm, more preferably at most 0.007/cm, more preferably at most 0.006/cm.
    In some embodiments, Ext:(436 nm), Ext:(546 nm), and Ext; (644 nm) at least 0.0001/cm, at least 0.0002/cm, at least 0.0003/cm or at least 0.0005/cm.
    Another important parameter is the thermal conductivity k.
    Thermal conductivity is the product of density, specific heat capacity and thermal diffusivity.
    The density is preferably determined according to the Archimedes principle (in particular ASTM C693:1993). In order to determine the temperature dependency of the density, the expansion behavior is preferably determined by means of dilatometry, as described under DIN 51045-1:2005-08 and DIN ISO 7991:1998-02.
    The specific heat capacity is preferably determined using DSC (dynamic differential calorimetry; English: "differential scanning calorimetry" in accordance with DIN 51007:2019-04.
    The thermal conductivity is preferably determined using flash analysis in accordance with ASTM E1461:2013.
    A high thermal conductivity k limits the stationary increase in temperature of the optical glass in the beam path.
    The thermal conductivity k is preferably more than 0.005 W/(cm*K), more preferably at least 0.006 W/(cm*K), more preferably at least 0.007 W/(cm*K), more preferably at least 0.008 W/(cm*K ), for example at least 0.009 W/(cm*K) or at least 0.010 W/(cm*K). In some embodiments, the thermal conductivity k is at most 0.050 W/(cm*K), at most 0.040 W/(cm*K), at most 0.030 W/(cm*K), at most 0.020 W/(cm*K) or at most 0.015 W /(cm*K). As described above, the beam guidance elements are made of a glass that is particularly resistant to solarization, particularly in the blue spectral range.
    This is advantageous for corresponding applications in projectors and in material processing, as it drastically reduces the occurrence of thermal lens effects.
    Other aspects can also contribute to the reduction of thermal lens effects.
    For example, with a given local deposited heat output (due to absorption of the laser light), the stationary temperature difference that occurs with increasing heat conduction becomes smaller and thus the temperature-induced aberrations.
    A high thermal conductivity k is therefore advantageous.
    Depending on the area of application, the refractive index can also play a role.
    The refractive index is preferably in a range from 1.45 to 1.65 at a wavelength of 436 nm, 546 nm and/or 644 nm. It has been shown that a wide variety of glass families can be used in order to obtain a glass with a figure of merit according to the invention.
    The glass is preferably selected from the group consisting of fluorophosphate glass, silicate glass, borosilicate glass, niobium phosphates and aluminoborosilicate glass. The refining agents used are particularly relevant, as explained below.
    The beam guidance element preferably consists of a glass comprising the following components in the stated proportions (in % by weight). Per TE) around (© w# |
    CO CE mm (© = | w (© FF | w (© >» | w (© = | mo EP | me (© >» | w (© = | w (© = | wm (© = | um (© 5 | w EE | $ej = mu j = ma (© = | pr (6 = | mo (© w# | mo © | Ca The glass of the invention may be, for example, a fluorophosphate glass. A particularly preferred fluorophosphate glass of the invention comprises the following components in the stated proportions (in % by weight).
    DC um (© F | uw (© FF | w (© F | w EE w © F | mo |T w | w «ë@ | MOSS
    SE Las 8 EF) me © 5 _ Ma B LE pe BP |] The fluorophosphate glass according to the invention preferably contains less than 0.3% by weight, more preferably at most 0.2% by weight, more preferably at most 0.1% by weight. -% of each of the components SiO2, B2O3, Li2O, NazO, K2O, ZnO, TiO2, ZrO2, La20O3, Sb2Os, As20O3 and SNO2 or is particularly preferably even free of these components. The fluorophosphate glass preferably contains Al2O3 in a proportion of 7.5 to 22.5% by weight, more preferably 10 to 20% by weight, more preferably 14 to 19% by weight. The fluorophosphate glass preferably contains MgO in a proportion of 1.5 to 7.5% by weight, more preferably 2 to 5% by weight, more preferably 2.5 to 3.5% by weight. The fluorophosphate glass preferably contains CaO in a proportion of 7.5 to 15% by weight, more preferably 9 to 14% by weight, more preferably 10 to 13% by weight. The fluorophosphate glass preferably contains BaO in a proportion of 11 to 25% by weight, more preferably 12 to 20% by weight, more preferably 13 to 17% by weight. The fluorophosphate glass preferably contains SrO in a proportion of 15 to 24% by weight, more preferably 16 to 23% by weight, more preferably 16.5 to 22% by weight. The fluorophosphate glass preferably contains P2Os in a proportion of 6 to 12% by weight, more preferably 7 to 11% by weight, more preferably 8 to 10% by weight. The fluorophosphate glass preferably contains F in a proportion of 20 to 40% by weight, more preferably 25 to 35% by weight, more preferably 27.5 to 32.5% by weight. The glass of the invention can be, for example, a silicate glass. A particularly preferred silicate glass of the invention comprises the following components in the indicated proportions (in % by weight). ee uw © FE | mo © FF | mo |@ = | œ B B] EB |
    EE ra EB | re | | mo € |w |
    A va PP | The silicate glass according to the invention preferably contains less than 0.3% by weight, more preferably at most 0.2% by weight, more preferably at most 0.1% by weight of each of the components B2O3, Al2O3, MgO, CaO, SrO, TiO2, P2Os, F, Sb2O3 and As2O3 or is particularly preferably even free of these components. The silicate glass preferably contains SiO2 in a proportion of 35 to 50% by weight, more preferably 37.5 to 47.5% by weight, more preferably 40 to 45% by weight. The silicate glass preferably contains Li:O in a proportion of 0.2 to 4% by weight, more preferably 0.4 to 2% by weight, more preferably 0.5 to 1.5% by weight. The silicate glass preferably contains NazO in a proportion of 2 to 15% by weight, more preferably 3 to 10% by weight, more preferably 4 to 7.5% by weight. The silicate glass preferably contains K2O in a proportion of 1 to 10% by weight, more preferably 1.5 to 7.5% by weight, more preferably 2 to 5% by weight. The sum of the proportions of the alkali metal oxides (R2O) in the silicate glass is preferably in a range from 1 to 20% by weight, more preferably from 2 to 15% by weight, more preferably from 5 to 12.5% by weight. . In addition to Li2O, Na2O and/or K:O, the glass preferably contains no further alkali metal oxides. The silicate glass preferably contains BaO in a proportion of 2 to 25% by weight, more preferably 5 to 20% by weight, more preferably 7.5 to 15% by weight. The silicate glass preferably contains ZnO in a proportion of 5 to 30% by weight, more preferably 10 to 27.5% by weight, more preferably 15 to 25% by weight. The silicate glass preferably contains ZrO2 in a proportion of 1.5 to 10% by weight, more preferably 2 to 8.5% by weight, more preferably 3 to 7% by weight. The silicate glass preferably contains La:O3 in a proportion of 2 to 20% by weight, more preferably 5 to 15% by weight, more preferably 7.5 to 12.5% by weight. The silicate glass preferably contains SnO2 in a proportion of 0.05 to 0.4% by weight, more preferably 0.1 to 0.35% by weight, more preferably 0.15 to 0.25% by weight. -%.
    The glass of the invention can be, for example, a borosilicate glass.
    A particularly preferred borosilicate glass of the invention comprises the following components in the indicated proportions (in % by weight). |] mw Ee ml | | we PF | mo BE where B PF | œ B|w| w B | w | w EB | w le | | mm @ |; | a Ba EE ra EB re |» | mo je jo | mo Ee | va B | The borosilicate glass according to the invention preferably contains less than 0.3% by weight, more preferably at most 0.2% by weight, more preferably at most 0.1% by weight of each of the components Al2O3, Li2O, MgO, ZnO, SrO, ZrO:, La2OO3, P2O5, As2O3 and SnO: or is particularly preferably even free of these components.
    The borosilicate glass preferably contains SiO2 in a proportion of 52.5 to 77.5% by weight, more preferably 55 to 75% by weight, more preferably 57.5 to 72.5% by weight. The borosilicate glass preferably contains B203 in a proportion of 5 to 25% by weight, more preferably 7.5 to 20% by weight, more preferably 9 to 19% by weight. The borosilicate glass preferably contains Na2O in a proportion of 0 to 17.5% by weight, more preferably 0 to 15% by weight, more preferably 0 to 12.5% by weight. In certain embodiments, the glass contains at least 2%, at least 5% or even at least 8% by weight Na:O. The borosilicate glass preferably contains K2O in a proportion of 2 to 24% by weight, more preferably 4 to 23% by weight, more preferably 6 to 22% by weight.
    The sum of the proportions of the alkali metal oxides (R2O) in the borosilicate glass is preferably in a range from 5 to 30% by weight, more preferably from 10 to 25% by weight, more preferably from 15 to 22% by weight. In addition to Na:O and/or K2O, the glass preferably contains no further alkali metal oxides.
    The borosilicate glass preferably contains CaO in a proportion of 0 to 5% by weight, more preferably 0 to 2% by weight, more preferably 0 to 1% by weight. In certain embodiments, the glass contains at least 0.1% or at least 0.2% by weight of CaO.
    The borosilicate glass preferably contains BaO in a proportion of 0 to 5% by weight, more preferably 0 to 3.5% by weight, more preferably 0 to 2% by weight. In certain embodiments, the glass contains at least 0.1% by weight BaO.
    The borosilicate glass preferably contains TiO2 in a proportion of 0 to 2% by weight, more preferably 0 to 1% by weight, more preferably 0 to 0.5% by weight. In certain embodiments, the glass contains at least 0.1% by weight TiO.2.
    The borosilicate glass preferably contains F in a proportion of 0 to 15% by weight, more preferably 0 to 12.5% by weight, more preferably 0 to 10% by weight. In certain embodiments, the glass contains at least 1% by weight, at least 2% by weight or even at least 5% by weight of F.
    The borosilicate glass preferably contains Sb2O3 in a proportion of 0.01 to 0.45% by weight, more preferably 0.01 to 0.4% by weight, more preferably 0.01 to 0.35% by weight .
    The glass of the invention may be, for example, an aluminoborosilicate glass. A particularly preferred aluminoborosilicate glass of the invention comprises the following components in the proportions indicated (in % by weight).
    ee mu ® w ® | w © Mon 9 | | œ BE w © PF | w © [B vw BE um © FE | a | Where € # | CO
    FU 88 2 mo je jo | mo Ee | The aluminoborosilicate glass according to the invention preferably contains less than 0.3% by weight, more preferably at most 0.2% by weight, more preferably at most 0.1% by weight of each of the components Li2O, MgO, CaO, SrO, TiO2, ZrO2, La2Os, P2O5, As2O3 and SnO: or is particularly preferably even free of these components.
    The aluminoborosilicate glass preferably contains SiO2 in a proportion of 62.5 to 77.5% by weight, more preferably 65 to 75% by weight, more preferably 67.5 to 72.5% by weight. The aluminoborosilicate glass preferably contains B2O: in a proportion of from 7.5 to 25% by weight, more preferably from 10 to 20% by weight, more preferably from 12.5 to 17.5% by weight. The aluminoborosilicate glass preferably contains Na2O in a proportion of 0.2 to 10% by weight, more preferably 0.5 to 5% by weight, more preferably 1 to 3% by weight.
    The aluminoborosilicate glass preferably contains K2O in a proportion of 2 to 17.5% by weight, more preferably 5 to 15% by weight, more preferably 10 to 14% by weight.
    The sum of the proportions of the alkali metal oxides (R2O) in the aluminoborosilicate glass is preferably in a range from 2 to 25% by weight, more preferably from 5 to 20% by weight, more preferably from 10 to 15% by weight. In addition to Na:O and/or K:O, the glass preferably contains no further alkali metal oxides.
    The aluminoborosilicate glass preferably contains BaO in a proportion of 0.02 to 5% by weight, more preferably 0.05 to 2% by weight, more preferably 0.1 to 1% by weight. The aluminoborosilicate glass preferably contains ZnO in a proportion of 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, more preferably 0.15 to 1% by weight.
    The aluminoborosilicate glass preferably contains F in a proportion of 0.1 to 5% by weight, more preferably 0.2 to 2% by weight, more preferably 0.5 to 1.5% by weight.
    The aluminoborosilicate glass preferably contains Sb2O3 in a proportion of 0.02 to 0.45% by weight, more preferably 0.05 to 0.4% by weight, more preferably 0.1 to 0.35% by weight .
    The refining agents used, as well as CeO2 and Fe2O3, are particularly relevant, regardless of the glass system used. The following information is therefore valid for all glass families.
    The glass is preferably free of CeO2 and Fe2Os. This allows particularly low exto values to be achieved.
    The proportion of As:O; in the glasses according to the invention less than 0.3% by weight, preferably at most 0.2% by weight, more preferably at most 0.1% by weight. Even more preferably, the glass is free from As2O3. As a result, particularly low Ext; Vverts can be achieved.
    The proportion of Sb2O3 in the glasses according to the invention is preferably at most 0.5% by weight, preferably at most 0.4% by weight, more preferably at most 0.3% by weight, for example at most 0.2% by weight or at most 0.1% by weight. The glass can even be free of Sb2O; be. This allows particularly low Ext: values to be achieved.
    The proportion of SnO2 in the glasses according to the invention is preferably at most 0.5% by weight, preferably at most 0.4% by weight, more preferably at most 0.3% by weight, for example at most 0.2% by weight or at most 0.1% by weight. The glass can even be free of SnOz. This allows particularly low Ext: values to be achieved.
    The proportion of the sum of As2O3+Sb2Os+SnO» is preferably at most 0.5% by weight, preferably at most 0.4% by weight, more preferably at most 0.3% by weight, for example at most 0.2% by weight % or at most 0.1% by weight. The glass can even be free from As2Os, Sb2O; and be SnO2. This allows particularly low Ext: values to be achieved. The glass can contain F, for example in a proportion of 0 to 45% by weight, in particular 0.5 to 42.5% by weight or 5 to 40% by weight. As a result, particularly low Ext; values can be achieved. The glass may also contain Cl, particularly due to Cl fining. The proportion is preferably <2% by weight, preferably <1.5% by weight, particularly preferably <1% by weight. If the Cl content is too high, this can lead to undesirable salt precipitation on the glass. When it is stated in this description that the glasses are free of a component or do not contain a certain component, this means that this component may at most be present as an impurity in the glasses. This means that it is not added in significant amounts. Insubstantial amounts according to the invention are amounts of less than 500 ppm, preferably less than 300 ppm, preferably less than 100 ppm, more preferably less than 50 ppm and most preferably less than 10 ppm, in each case on a weight basis. The beam guiding element is preferably a lens, a light guide rod, a prism or an asphere, particularly preferably a prism. The present invention also relates to a glass which has a figure of merit according to the invention. The present invention also relates to the use of an imaging system according to the invention, in particular in a projector, or in material processing. The invention also relates to a projector comprising an imaging system according to the invention, in particular a DLP projector. Description of the Figures Figure 1 shows schematically an embodiment of the present invention. An exemplary embodiment of the imaging system as a DLP projector is shown. The three colors blue, green and red (arrow 5) generated by the laser light source(s) 1 reach after leaving the
    Laser light source(s) 1, the beam guidance element 2. The beam guidance element 2 deflects the light onto imaging chips 3 (arrow 6). The images generated by the imaging chips 3 (in particular an image each in blue, green and red) then reach the beam guidance element 2 . This is shown by the arrow 7 . The beam guidance element 2 then ensures that a composite color image reaches the projection optics 4 . This is shown by arrow 8.
    Figure 2 shows the emission spectrum of the Philips HOK 4/120 lamp. The wavelength in nm is shown on the x-axis. The relative intensity compared to the maximum intensity is shown on the y-axis.
    Figure 3 is a bar graph showing the figure of merit F(436 nm) and the figure of merit F(RGB) for five Examples 1-5 of the invention and one Comparative Example A not of the invention.
    EXAMPLES Samples of five example glasses 1 to 5 according to the invention and a comparative example A not according to the invention with a sample thickness of 10 mm were each irradiated for 15 hours with an HOK 4 lamp. A Philips HOK 4/120 lamp was used. The spectrum of this HOK 4/120 lamp is shown in FIG. The distance between the lamp and the sample was 7 cm. The power density was 25 mW/cm². The sample size was mm x 30 mm x 10 mm. The compositions of the glasses are shown in Table 1 below (in % by weight).
    20 Table 1
    EN ae [EE [B Bo [B mo [EE
    CO won JE wp #7 [Ee 2 Mo | | Et ao 1902 | | Bao 1 192 9IM | | mo | 92 2OL2 | SrO 18 e= | | 8 | pe me | | 11° | | F | 1 FE me | | (FT | 1° FE P2O ra [LB
    EB JE mo | JB | | we | mo | | | 1 8 | a | | 2 | 0 The figure of merit F(436 nm), the figure of merit F(546 nm), the figure of merit F(644 nm) and the figure of merit F(RGB) were calculated using the formulas given above.
    For this purpose, the corresponding values of the thermality S, the non-induced extinction Exto and the induced extinction Ext; for the wavelengths 436 nm, 546 nm and 644 nm as well as the thermal conductivity k of the glass.
    The results are shown in Figure 3.
    Table 2 below summarizes the measurements and calculations.
    Table 2
    Ee Ee Es [Et os VBA
    S(436nm)
    S(546nm)
    S(644nm)
    Exto(436nm)
    Exto(546nm)
    Exto(644nm)
    Ext:(436nm)
    Ext:(546nm)
    Ext:(644nm)
    F(436nm
    F(546nm)
    F(644nm) F(RGB)
    pres |1ro—_|es [am on Je | It can be seen that glasses 1 to 5 according to the invention, in contrast to comparative example A, have a quality factor F(436 nm)<700 ppm/W, a quality factor F(546 nm)<215 ppm/W,
    have a figure of merit F(644 nm) < 85 ppm/W and a figure of merit F(RGB) < 1000 ppm/W.
    Example glass 3 and comparative example A have very similar compositions and differ essentially in that comparative example A contains a relevant proportion of As2O3. The result shows a much improved performance of example 3. Remarkably, the effect can be achieved with glasses from many different glass families. Examples 1 and 5 are borosilicate glasses, example 2 is an aluminoborosilicate glass, example 3 is a silicate glass and example 4 is a fluorophosphate glass. LIST OF REFERENCE NUMERALS 1 Laser light source(s) 2 Beam guiding element 3 Imaging chips 4 _ Projection optics 5 Light reaches the beam guiding element from the laser light source(s) 6 Light is deflected by the beam guiding element to the imaging chips 7 The images generated by the imaging chips reach the beam guiding element 8 A composite color image arrives to the projection optics
    权利要求:
    Claims (15)
    [1]
    1. Imaging system comprising a) at least one laser light source selected from the group consisting of a laser light source B with a wavelength λ8 in the spectral range from 380 nm to 490 nm, a laser light source G with a wavelength Ac in the spectral range from > 490 nm to 585 nm and a laser light source R with a wavelength Ar in the spectral range from > 585 nm to 750 nm, and b) a beam guidance element, wherein the laser light source B, the laser light source G and/or the laser light source R is suitable, in at least one point of the beam guidance element a middle Area power density of more than 10 W/cm and the beam guidance element consists of a glass with a quality factor F(436 nm) = S(436 nm) *(Exto(436 nm) + Ext:(436 nm))/k, where S(436 nm) the thermality at a wavelength of 436 nm, Ext:(436 nm) the additional absorbance at a wavelength of 436 nm compared to Exto(436 nm) of a sample with a thickness d of 10 mm after 15 hours irradiation with a ner HOK 4 lamp with a distance between the lamp and the sample of 7 cm, Exto(436 nm) is the absorbance at a wavelength of 436 nm of a sample with a thickness of 10 mm without irradiation with the HOK 4 lamp and k is the thermal conductivity , where the extinction is the quotient of the natural logarithm of the quotient of the incident radiation lo and the exiting radiation | with the wavelength À as the dividend and the sample thickness d as the divisor (Ext(A) = In(lo/)/d), and where F(436 nm) < 700 ppm/W.
    [2]
    2. Imaging system according to claim 1, comprising a laser light source B with a wavelength As in the spectral range from 380 nm to 490 nm, a laser light source G with a wavelength As in the spectral range from > 490 nm to 585 nm and a laser light source R with a Wavelength Ar in the spectral range from > 585 nm to 750 nm, where the laser light source B, the laser light source G and the laser light source R are suitable, an average areal power density of more than 10 W/cm in at least one point of the beam guidance element and the beam guiding element consists of a glass with a quality factor F(RGB) = F(436 nm) + F(546 nm) + F(644 nm) = S(436 nm)*(Exto(436 nm) + Ext:(436nm))/k + S(546nm)*(Exto(546nm) + Ext:(546nm))/k + S(644nm)*(Exto(644nm) + Ext:(844 nm))/k, where F(RGB) < 1000 ppm/W.
    [3]
    3. The imaging system of claim 2, wherein F(RGB) is at most 800 ppm/W.
    [4]
    4. The imaging system of at least one of the preceding claims, wherein the laser light source is a diode laser.
    [5]
    5. Imaging system according to at least one of the preceding claims, wherein the beam guiding element is a prism.
    [6]
    6. Imaging system according to at least one of the preceding claims, wherein the laser light source is suitable, in at least one point of the beam guidance element, has an average areal power density of 15 W/cm up to 60 W/cm to create.
    [7]
    7. Imaging system according to at least one of the preceding claims, wherein S(436 nm), S(546 nm) and S(644 nm) are at most 50 ppm/K.
    [8]
    8. The imaging system of at least one of the preceding claims, wherein Exto(436nm), Exto(546nm) and Exto(644nm) are less than 0.01/cm.
    [9]
    9. The imaging system of at least one of the preceding claims, wherein Ext:(436 nm), Ext:(546 nm) and Ext:(644 nm) are less than 0.3/cm.
    [10]
    10. Imaging system according to at least one of the preceding claims, wherein the thermal conductivity k is more than 0.005 W/(cm*K).
    [11]
    11. Imaging system according to at least one of the preceding claims, wherein the mean dn/dT at a wavelength of 436 nm, 546 nm and/or 644 nm in a temperature range of 20°C to 40°C is in a range of 0 .1 to 8.0 ppm/K.
    [12]
    12. Beam guiding element consisting of a glass having a figure of merit F(436 nm) = S(436 nm)*(Exto(436 nm) + Ext:(436 nm))/k, where F(436 nm) < is 700 ppm/W.
    [13]
    13. Glass having a figure of merit F(436nm) = S(436nm)*(Exto(436nm) + Ext:(436nm))/k, where F(436nm) < 700ppm/W is.
    [14]
    14. Use of an imaging system according to at least one of claims 1 to 11 in a projector or in material processing.
    [15]
    15. Projector comprising an imaging system according to at least one of claims 1 to
    11.
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    同族专利:
    公开号 | 公开日
    DE102020114365A1|2021-12-02|
    US20210373426A1|2021-12-02|
    BE1028287A1|2021-12-06|
    CA3119826A1|2021-11-28|
    CN113740937A|2021-12-03|
    JP2021189453A|2021-12-13|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5925468A|1996-04-12|1999-07-20|Corning Incorporated|Solarizaton resistant and UV blocking glass|
    US20180136446A1|2015-05-21|2018-05-17|Q-State Biosciences, Inc.|Optogenetics microscope|
    DE10108992C2|2001-02-23|2003-04-03|Schott Glas|Solarization-stable borosilicate glass and its uses|
    CN101431216B|2003-12-22|2010-11-03|松下电器产业株式会社|Semiconductor laser device and laser projector|
    DE102008010407B4|2007-02-26|2016-10-13|Z-Laser Optoelektronik Gmbh|Method and device for projecting an optical projection on a projection surface|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102020114365.6A|DE102020114365A1|2020-05-28|2020-05-28|Imaging system comprising beam guiding element with high solarization resistance in the visible spectral range|
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