Miniaturized optical devices, such as spectrometers and spectrometer modules, and their manufacture

Abstract

A method for manufacturing an optical device comprising providing a plurality of initials bars each having a first side face presented with a first optical component arrangement; positioning the initial bars in a row with their first side faces facing a neighboring one of the initial bars; fixing the initial bars to obtain a bar arrangement; obtaining prism bars by segmenting the bar arrangement by at least one of the steps: conducting a plurality of cuts so that each prism bar comprises a portion of at least two different ones of the initial bars, separating the bar arrangement into sections along cut lines or by creating cut faces at an angle with initial-bar directions; dividing the first optical component arrangement for obtaining a plurality of passive optical components, wherein each prism bar comprises one or more passive optical components comprising a first reflective face each which is of non-planar shape; segmenting prism bars into parts.

Claims

1. A method for manufacturing an optical device, the method comprising a) providing a plurality of bars referred to as initial bars, each initial bar extending along a respective initial-bar direction from a first bar end to a second bar end and having a first side face extending from the first bar end to the second bar end, a first optical component arrangement being present at the first side face; b) positioning the initial bars in a row with their respective initial-bar directions aligned parallel to each other and with their respective first side faces facing towards a neighboring one of the initial bars; c) fixing the plurality of initial bars with respect to each other in the position achieved in step b) to obtain a bar arrangement; the method further comprising d0) obtaining bars referred to as prism bars by carrying out at least one of steps d), d′), d″): d) segmenting the bar arrangement into the prism bars each of which comprises a portion of at least two different ones of the plurality of initial bars, by conducting a plurality of cuts through the bar arrangement; d′) segmenting the bar arrangement into the prism bars by separating the bar arrangement into sections along cut lines, wherein the cut lines are at an angle with the initial-bar directions; d″) segmenting the bar arrangement into the prism bars by separating the bar arrangement into sections by creating cut faces which are at an angle with respect to the initial-bar directions; wherein the segmenting the bar arrangement into the prism bars comprises dx) dividing the first optical component arrangement for obtaining a plurality of passive optical components, wherein each of the prism bars comprises one or more of the passive optical components comprising a first reflective face each which is of non-planar shape; the method further comprising e) segmenting the prism bars into parts.

2. The method according to claim 1, wherein step c) comprises attaching the initial bars to a first substrate.

3. The method according to claim 2, wherein the first substrate comprises at least one protrusion protruding between neighboring initial bars in the bar arrangement.

4. The method according to claim 3, wherein the protrusion functions as a baffle in the optical device.

5. The method according to claim 2, wherein the first substrate comprises at least one transparent portion adjoining open space present between neighboring initial bars in the bar arrangement.

6. The method according to claim 5, wherein the at least one transparent portion is a material transparent portion.

7. The method according to claim 1, wherein the first optical component arrangement comprises an array of distinct passive optical components.

8. An optical device comprising; a first outer side panel; a first member including a first base face and a second base face, and a first reflective face and a second reflective face, the second reflective face facing the first reflective face; wherein the first base face is aligned parallel to the first outer side panel and attached thereto; wherein at least one of the first and second reflective faces is of non-planar shape; and wherein the optical device further comprises a focusing element including the first or second reflective face; or the first outer side panel includes a baffle; or the first outer side panel includes a transparent portion.

9. An optical device comprising: a first outer side panel; a first member including a first base face, a second base face, a first reflective face, and a second reflective face, the second reflective face facing the first reflective face; a second member including a first further base face, a second further base face, and the second reflective face; a third outer side panel aligned parallel to the first outer side panel; a diffractive element including the first reflective face or the second reflective face; a focusing element including the first reflective face or the second reflective face; wherein the first base face is aligned parallel to the first outer side panel and attached thereto, wherein at least one of the first and second reflective faces is of non-planar shape; wherein the first further base face is aligned parallel to the first outer side panel and attached thereto, wherein the second base face and the second further base face are aligned parallel to the third outer side panel and attached thereto; and wherein the optical device defines an optical path for light entering the optical device, wherein light propagating along the optical path for light is diffracted by the diffractive element and focused by the focusing element.

10. The optical device of claim 9, further comprising an entrance slit at a beginning of the optical path for light and a collimating element situated along the optical path for light between the entrance slit and the diffractive element.

11. A compound optical device including a first optical device and a second optical device, the first optical device and the second optical device each comprising: a first outer side panel; a first member including a first base face, a second base face, a first reflective face, and a second reflective face, the second reflective face facing the first reflective face; wherein the first base face is aligned parallel to the first outer side panel and attached thereto, and wherein at least one of the first and second reflective faces is of non-planar shape; and wherein the first optical device and the second optical device are fixed relative to one another and the compound optical device defines a light path for light entering the compound optical device, wherein the light path runs inside the first optical device and inside the second optical device.

12. The compound optical device of claim 11, wherein the first optical device and the second optical device are stacked upon each other.

13. The compound optical device of claim 12, wherein the first outer side panel of the first optical device is aligned perpendicularly to the first outer side panel of the second optical device.

14. The compound optical device of claim 12, wherein the first outer side panel of the first optical device is aligned parallel to the first outer side panel of the second optical device.

15. The compound optical device of claim 14, wherein the first outer side panel of the first optical device and the first outer side panel of the second optical device are arranged in different planes, which are arranged at a distance to each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Below, the invention is described in more detail by means of examples and the included drawings. In the drawings, same reference numerals refer to same or analogous elements. The figures show schematically:

(2) FIGS. 1a-1c schematical illustrations in a top view of a manufacture of initial bars;

(3) FIGS. 2a-2c schematical illustrations in a cross-sectional view of a manufacture of initial bars;

(4) FIGS. 3a-3c schematical illustrations in a cross-sectional view of a positioning of initial bars using a jig;

(5) FIG. 4 a schematical illustration in a cross-sectional view of a positioning of initial bars using another jig;

(6) FIG. 5 a schematical illustration in a top view of a manufacture of a bar arrangement;

(7) FIG. 6 a schematical illustration in a cross-sectional view of the manufacture of a bar arrangement illustrated in FIG. 11b;

(8) FIG. 7 a schematical illustration in a top view of a manufacture of prism bars from the bar arrangement of FIGS. 11c, 12c;

(9) FIG. 8 a schematical illustration in a cross-sectional view of the manufacture of prism bars illustrated in FIG. 13;

(10) FIG. 9 a schematical cross-sectional view of a prism bar;

(11) FIG. 10 a schematical illustration in a cross-sectional view of an attaching of the prism bar of FIG. 17 to a second substrate with baffles for manufacturing a type II-like optical device;

(12) FIG. 11 a schematical cross-sectional view of a type II-like optical device constituting a module for a spectrometer;

(13) FIG. 12 a schematical cross-sectional view of a type II-like optical device constituting a spectrometer;

(14) FIG. 13a a schematical rear view of a compound optical device;

(15) FIG. 13b a schematical cross-sectional side view of the compound optical device of FIG. 13a;

(16) FIG. 14a a schematical rear view of a compound optical device;

(17) FIG. 14b a schematical cross-sectional top view of the compound optical device of FIG. 14a;

(18) FIG. 15 a schematical rear view of a compound optical device;

(19) FIG. 16 a schematical rear view of an initial bar with passive optical components on a precursor bar;

(20) FIG. 17 a schematical perspective view of an initial bar with a continuous optical structure.

(21) The described embodiments are meant as examples or for clarifying the invention and shall not limit the invention.

DETAILED DESCRIPTION OF THE INVENTION

(22) In the following, ways of manufacturing optical devices are explained. In some of the Figures, small coordinate systems are symbolized for explaining the orientation of the illustrated parts. Therein, x, y, z designate coordinates related to the initial bars, while x′, y′, z′ designate coordinates related to prism bars.

(23) The manufacturing can be accomplished on wafer level, thus making possible to manufacture high numbers of high precision parts within a relatively small period of time and/or by means of a relatively low number of processing steps.

(24) FIGS. 1a-1c are schematical illustrations in a top view of a manufacture of initial bars 2.

(25) FIGS. 2a-2c are schematical illustrations in a cross-sectional view of the manufacture of initial bars 2.

(26) FIGS. 1a, 2a illustrate a plate 6 having an upper face 6a and a lower face 6b, wherein first passive optical components 21p are present at face 6a, and second passive optical components 23p are present at face 6b. The passive optical components 21p, 23p can be reflective passive optical components. The passive optical components can be, e.g., produced using a replication technique, e.g., with a subsequent coating step to provide reflectivity. Between replication material from which the passive optical components are formed, a core 6c can be present.

(27) The passive optical components can be, e.g., curved mirrors or gratings, e.g., curved gratings.

(28) In FIGS. 1b, 2b, separation lines are indicated by dashed lines, which are also symbolized in the coordinate systems. By separating plate 6 along these lines, a plurality of initial bars 2 is obtained, as illustrated in FIGS. 1c, 2c.

(29) Each initial bar 2 has a first bar end 28 and a second bar end 29 and four side faces 21, 22, 23, 24, wherein a plurality of passive optical components 21p is present at first side face 21, and a plurality of passive optical components 23p is present at third side face 23.

(30) The initial bars are, in some embodiments, congeneric. But this does not need to be the case.

(31) Furthermore, passive optical components 21p and 23p do not need to be congeneric passive optical components; they do not even have to be produced and placed, respectively, in the same way.

(32) And still furthermore, not all passive optical components 21p need to be congeneric. E.g., two or more different (non-congeneric) passive optical components can be present at the first side face 21. The same can apply to passive optical components 23p.

(33) In order to produce a bar arrangement 20 (cf., e.g., FIGS. 5, 6), the initial bars 2 have to be positioned suitably. Therein, side faces 21, 23 of the initial bars 2 at which passive optical components are present face each other. I.e. with respect to the mutual orientation the initial bars have during separation of plate 6 (cf. FIGS. 1c, 2c), each initial bar is rotated by 90° about the y axis corresponding to an initial-bar direction D, cf. FIG. 1c.

(34) One way of positioning the initial bars 2 is to use a jig 8 as illustrated in FIGS. 3a-3c.

(35) FIGS. 3a-3c are schematical illustrations in a cross-sectional view of a positioning of initial bars 2 using a jig 8.

(36) Jig 8 has a plurality of protrusions 81 on which an initial bar 2 can be positioned each. After attaching initial bars 2 to protrusions 81, spacers 8a are inserted between the initial bars 2 (cf. FIG. 3b). The spacers 8a can also be considered shims.

(37) By application of a force, e.g., by a spring or by applying a vacuum, a suitable, e.g., equidistant, spacing of the initial bars 2 is achieved, cf. FIG. 3c.

(38) Also other jigs can, alternatively, be used, e.g., jig 8′ as illustrated in FIG. 4.

(39) FIG. 4 is a schematical illustration in a cross-sectional view of a positioning of initial bars 2 using another jig 8′.

(40) Jig 8′ has grooves into which initial bars 2 can be inserted, thus ensuring a precise mutual alignment of the initial bars 2.

(41) A jig is used for the positioning only and will be removed later.

(42) Positioning the initial bars alone or together with further bars (an option which is generally described in above-cited WO 2016/076797, e.g., FIGS. 27-37 therein) without using a jig is possible, too, e.g., by simply pushing the bars against each other, each one against its one or two neighboring ones (cf., e.g., FIGS. 27a, 28a in WO 2016/076797).

(43) FIG. 5 is a schematical illustration in a top view of a manufacture of a bar arrangement 20, e.g., based on bars positioned as described above. FIG. 6 is a schematical illustration in a cross-sectional view of the manufacture of a bar arrangement illustrated in FIG. 5.

(44) In FIGS. 5, 6, the initial bars are positioned as required for the desired bar arrangement. A jig possibly used for the positioning of the initial bars 2 is not illustrated here. The initial bars 2 can be fixed relative to each other by attaching one or two substrates 11, 12 to the bar arrangement 20. After attachment to a first substrate 11, a jig, if applied before, can be removed from the bar arrangement. However, the positioned initial bars as illustrated, e.g., in FIGS. 5, 6, but without a substrate can represent a bar arrangement, too.

(45) FIGS. 5, 6 illustrate attaching a first substrate 11 to bar arrangement 20. Similarly, a third substrate 13 can be attached to bar arrangement 20, cf. FIGS. 7, 8.

(46) FIG. 7 is a schematical illustration in a top view of a manufacture of prism bars 4 from the bar arrangement 20; and FIG. 8 is a schematical illustration in a cross-sectional view of the manufacture of prism bars 4 illustrated in FIG. 7.

(47) Substrates 11, 13 are illustrated to include optional protrusions which function as baffles b1, b3.

(48) In FIGS. 7, 8, the initial bars 2 are sandwiched between first and second substrates 11, 13. A wafer stack is obtained in which the initial bars 2 are positioned with respect to each other with high precision.

(49) In a next step, the obtained wafer stack is separated into bars referred to as prism bars. Therein, cut lines C of the separation are at an angle with the initial-bar lines D, e.g., at an angle of 45°, as illustrated.

(50) FIG. 9 is a schematical cross-sectional view of a prism bar 4, as obtained according to FIGS. 7, 8.

(51) In the coordinate system of the prism bar 4, x′ is a coordinate along the extension of the prism bar 4 (“prism bar direction”)—which runs somewhere (depending on the cutting angle) between the x and y coordinates of the initial bar coordinate system. It corresponds, in the produced optical device to a primary direction of the produced part or optical device. And z′ is a height coordinate of the prism bar 4—which corresponds to the opposite direction of the y coordinate.

(52) FIG. 10 is a schematical illustration in a cross-sectional view of an attaching of the prism bar 4 of FIG. 9 to a second substrate 12 for manufacturing a type II-like optical device. Second substrate 12—which can also be considered a “further substrate”—includes a plurality of optional protrusions. Those protrusions can function as baffles b2.

(53) It is possible to position a plurality of prism bars 4 on such a second substrate 12, e.g., using pick-and-place. However, it is possible to form a prism bar arrangement from a plurality of prism bars, by mutually aligning prism bars 4 and fixing them relative to each other, e.g., similarly to what is described for the formation of an (initial) bar arrangement, e.g., using a jig.

(54) The dashed lines indicate where separation of the prism bars takes place, so as to obtain parts which are type-II-like optical devices. For type-I-like optical devices, the separation would take place, e.g., in the middle between the dashed lines.

(55) Opposite to second substrate 12, a fourth substrate can be attached to the prism bars and to the prism bar arrangement, respectively, such that these are sandwiched between the second and the fourth substrate.

(56) FIG. 11 is a schematical cross-sectional view of an optical device of type II constituting a module for a spectrometer.

(57) It includes a first member 41 and a second member 42, at opposite ends of the optical device 1, which include passive optical components 21p and 23p, respectively.

(58) Second and fourth outer side panels 62, 64 of optical device 1 are visible in the cross-section of FIG. 11, whereas first and third outer side panels are above and below the drawing plane, respectively.

(59) Base faces of the members 41, 42 are parallel to and attached to the first and third outer side panels.

(60) The members 41, 42 are sections of the initial bars; the first and third outer side panels are sections of the first and third substrates, respectively, (which were included in the bar arrangement); and the second and fourth outer side panels are sections of the second and fourth substrates, respectively, (which were attached to the prism bars).

(61) In outer side panel 64, a transparent portion 64a is provided which establishes an entrance slit in the otherwise non-transparent panel.

(62) In outer side panel 62, a transparent portion 62a is provided to which a lens element 15 is attached, e.g., for focusing purposes. Otherwise, outer side panel 62 can be non-transparent panel.

(63) One or more of the outer side panels 62, 64 can include protrusions functioning as baffles. In FIG. 11, merely as an example, baffles b2 and b4 of outer side panels 62 and 64, respectively, are drawn.

(64) The transparent portions (such as transparent portions 62a and 64a) can be material, such as by including a transparent solid material (and no openings). But alternatively, any of the transparent portions can be an opening.

(65) Instead of lens element 15, another passive optical component could be provided; and the corresponding item could, alternatively or in addition, also be present on the inside of the optical device.

(66) Analogously, also at transparent portion 64a, a passive optical component could be provided.

(67) The passive optical component 21p at member 41 can be, e.g., a focusing mirror.

(68) The passive optical component 23p of member 42 can be, e.g., a curved diffraction grating.

(69) A cavity 9″ is enclosed by outer side panels 61, 62, 63, 64 and members 41, 42. This is an option for other embodiments, too. This protects the inside of the optical device, and in particular the surfaces of the of the passive optical components, from dirt.

(70) The optical device 1 illustrated in FIG. 11 defines a light path (illustrated by dotted arrows) for light entering the optical device through entrance slit 64a. Along the light path, the light is subsequently focused by mirror 21p, freed from stray light by the baffle including, e.g., baffles b2, b4, then diffracted and focused by curved grating 23p, to finally exit the optical device while being focused again, by lens element 15. The path (and in particular the angle) along which the light exits the optical device depends on the wavelength of the light.

(71) It can be sufficient to combine the optical device 1 of FIG. 11 with a detecting device such as a photodetector in order to obtain a full (but extremely small-sized) spectrometer.

(72) FIG. 12 is a schematical cross-sectional view of a type II-like optical device 1 constituting a spectrometer. This optical device is very similar to the one of FIG. 11, but it includes a detector 50, such as a one-dimensional or two-dimensional pixel arrangement, and the light path does not exit the optical device, but is detected by the detector 50, such that a transparent region 62a and a lens element 15 can be dispensed with. Second outer side panel 62 can be a printed circuit board to which detector 50 is attached and which has through contacts interconnecting electrical contacts of the detector 50 with outside contacts of the optical device (not specifically illustrated).

(73) For more complex devices, two or more of the described optical devices can be combined in a compound optical device.

(74) Producing compound optical devices can include, e.g., aligning a plurality of first prism bars relative to one another, so as to create a first prism bar arrangement, and aligning a plurality of second prism bars relative to one another, so as to create a second prism bar arrangement, and to attach the first prism bar arrangement to the second prism bar arrangement.

(75) FIGS. 13a and 13b schematically illustrate a compound optical device 100 in a rear view and in a cross-sectional side view, respectively. In this example, the first outer side panels 61i and 61j of the first optical device 1i and of the second optical device 1j, respectively, are aligned to lie in one and the same plane.

(76) FIGS. 14a and 14b schematically illustrate a compound optical device 100 in a rear view and in a cross-sectional top view, respectively. In this example, the first outer side panels 61i and 61j of the first optical device 1i and of the second optical device 1j, respectively, are aligned to lie in parallel, but distanced planes.

(77) As is readily perceived from the sketched light paths (dotted lines), valuable degrees of freedom in the optical design are opened up by the stacking of prism bars (e.g., in prism bar arrangements) or of the parts obtained by sectioning the prism bars or of prism bar arrangements.

(78) Further compound optical devices 100, e.g. as illustrated in a rear view in FIG. 15, can be produced when stacking is accomplished such that the first outer panel 61i of a first optical device 1i is aligned perpendicularly to the first outer panel 61j of a second optical device 1j.

(79) FIG. 16 is a schematical rear view of an initial bar 2 including passive optical components 21p on a precursor bar 21x. Passive optical components 21p can be pre-manufactured ones which are placed on the precursor bar 21x. Or, in another embodiment, the passive optical components 21p are produced and/or shaped on the precursor bar, e.g., using a replication process. The passive optical components 21p can be separate ones constituting an optical component arrangement including a plurality of distinct passive optical components.

(80) FIG. 17 is a schematical perspective view of an initial bar 2 with a continuous optical structure 21n. This continuous optical structure 21n can be, e.g., a curved mirror. It can be separated into distinct passive optical components at the time of producing the prism bars and of segmenting the bar arrangement, respectively. The outlined arrows indicate possible cutting planes.