DMD assembly and DLP projector comprising the same

Abstract

A DMD assembly comprises a first clamping element (12), a second clamping element (14), a number of screws (50) and corresponding receptacles (56), and force determining elastic elements. The first clamping element (12) and the second clamping element (14) are adapted to receive between them at least a DMD (16), an interposer (20), and a printed circuit board (22). The screws (50) and the corresponding receptacles (56) are arranged for forcing the first and the second clamping elements towards each other to fixedly clamp together at least a DMD (16), an interposer (20) and a printed circuit board (22). The force determining elastic elements are wave springs (48) and are arranged between each screw (50) and each receptacle (56) in order to determine the force forcing the first and the second clamping elements towards each other.

Description

[0001] D / BARUXR-024-DE

[0002] B240005 Description

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[0004] BARCO NV

[0005] 8500 Kortrijk, BE

[0006] DM D ASSEMBLY AND DLP PROJECTOR COMPRISING THE SAME

[0007] TECHNICAL FIELD

[0008] The invention relates to an assembly of a digital micromirror device, such devices being commonly known under the abbreviation DMD, a digital light processing 5 projector, commonly known as DLP projector, comprising such DMD assembly.

[0009] TECHNICAL BACKGROUND

[0010] 0 DMDs are a type of spatial light modulator used in various applications, including DLP projectors. DMDs consist of an array of tiny mirrors, each of which can be individually controlled to reflect light in a specific direction. This allows the DMD to modulate the intensity and direction of light to create an image.

[0011] In a DLP projector, the DMD is a core component that plays a central role in image projection. The DMD receives light from a light source and reflects it towards a projection lens, which then projects the image onto a screen. The quality of the projected image is largely dependent on the performance and stability of the DMD.

[0012] 0 DMDs are typically produced by specialized companies and are bought as separate components by manufactures of apparatus employing the DMDs. For its intendedD / BARUXR-024-DE

[0013] B240005 Description

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[0015] specific purpose in a respective complex apparatus such as a DLP projector, a DMD needs to be connected to a printed circuit board carrying respective hardware for powering and controlling the DMD, which is typically done by arranging the DMD, a so-called interposer acting as an electric interface, and the printed circuit board in 5 that order between two clamping elements and forcing the clamping elements together by means of screws. Surrounding the array of mirrors, the DMD is provided with a mounting surface area against which one of the clamping elements is acting. This clamping element has an opening to expose the array of mirrors.

[0016] While this "clamping together" sounds easy, it is in fact a delicate process, as it involves numerous tasks and needs to meet a couple of design and structural requirements. For example, the clamping force applied via the screws to the DMD to ensure its proper alignment and stability must be managed. Too much force can damage the DMD, while too little force can result in misalignment or instability. 5

[0017] In addition to mechanical stability, thermal management is another major consideration in DMD mounting. The DMD generates heat during operation, which can affect its performance and lifespan if not properly managed. Therefore, the mounting structure needs to incorporate a heat sink or a similar thermal

[0018] 0 management component to dissipate the heat generated by the DMD.

[0019] To work best, the heat sink needs to be brought into contact with the DMD. While in theory the contact between heat sink and DMD could also be indirect if some kind of adapter made of a material having a good thermal conductivity is interposed 5 between the DMD and the heat sink, which however would just add another component, direct contact between the heat sink and the DMD is preferred.

[0020] To ensure proper direct contact between the heat sink and the DMD, the heat sink typically comprises a portion called a cooling stud having a contact surface that in 0 shape and size basically corresponds to a so-called thermal interface area provided on the DMD, typically on a side opposite the side with DMD's mirrors. To expose this thermal interface area, while allowing the DMD to be clamped together with the interposer, the DMD comprises an electrical interface area surrounding the thermalD / BARUXR-024-DE

[0021] B240005 Description

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[0023] interface area. This electrical surface area also acts as a counterpart for the mounting surface area, that is the clamping forces holding the DMD act on these two areas. The interposer has an electrical interface area basically corresponding in shape and size to the electrical interface area of the DMD, and an opening exposing 5 the thermal interface area. The printed circuit board also has such opening, so that the cooling stud can be brought through the openings in the printed circuit board and the interposer into contact with the thermal interface area of the DMD.

[0024] The cooling stud's contact surface is pressed against the thermal interface area by forcing the heat sink with screws towards the DMD. Again, the force applied to the DMD, this time by the cooling stud, must be carefully managed, as too much force can damage the DMD, while too little force can result in instability and poor thermal contact.

[0025] 5 A particular challenge is the fact that the thermal interface area on the one hand and the electrical interface area and the mounting surface area on the other hand have different pressure tolerances, i.e. the force, with which the cooling stud's contact surface should be pressed against the thermal interface area and the clamping force acting on the electrical interface area and the mounting surface area are different.

[0026] 0 Typically, the force that should be applied by the cooling stud's contact surface on the thermal interface area is only about half of the clamping force.

[0027] To at least partially address the different problems involved with DMD mounting, both CN 111679396 A and US 11,265,521 B2 disclose DMD mounting structures 5 employing helical springs arranged somewhere along the screws and the respective elements. When the spring rate is known, i.e. when it is known, how much force required to compress (or extend) a spring by a unit distance, the springs can be used to determine and thus control the clamping forces and the force applied by the cooling stud's contact surface.

[0028] 0

[0029] However, as space is typically very limited in complex apparatus employing DM Ds, the final assembly obtained by using the DMD mountain structure to clamp together a DMD, an interposer and a printed circuit board and attaching a heat sink should beD / BARUXR-024-DE

[0030] B240005 Description

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[0032] very compact. Moreover, as the heat sink is attached to the DMD mounting structure, and the cooling stud in fact passes through clamping elements, the printed circuit board and the interposer before it finally reaches the thermal interface area, it needs to have in the hitherto known mounting structures a substantial length, which 5 delimits the cooling capabilities of the heat sink. The thermal resistivity of the cooling stud is proportional to its length divided by the size of its contact surface. Hence, as the contact surface is determined by the thermal interface area of the DMD, the shorter the cooling stud the smaller its thermal resistivity and the better the cooling effect.

[0033] In summary, the mounting of a DMD in a device such as an DLP projector involves a delicate balance of mechanical stability and thermal management. The choice of materials and design of the mounting structure for holding the DMD in place play a central role in achieving this balance, influencing the performance, reliability, and 5 lifespan of the DMD and, consequently, the quality of the projected image. Hence, there is a need for an improved mounting structure for holding the DMD in place.

[0034] DISCLOSURE OF THE INVENTION

[0035] 0

[0036] The invention aims at solving the aforementioned problems associated with the hitherto known DMD mounting structures and DMD assemblies.

[0037] The problems are solved by a DMD assembly according to claim 1. Independent claim 15 is directed to a DLP projector comprising a DMD assembly according to the invention. Advantageous embodiments are defined in the dependent claims.

[0038] According to the invention, a DMD assembly, comprises a first clamping element and a second clamping element, a number of screws and corresponding

[0039] 0 receptacles, and force determining elastic elements arranged between each screw and each receptacle. The first clamping element and the second clamping element are adapted to receive between them at least a DMD, an interposer, and a printed circuit board. The screws and the corresponding receptacles are adapted for forcingD / BARUXR-024-DE

[0040] B240005 Description

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[0042] the first and the second clamping elements towards each other to fixedly clamp together at least a DMD, an interposer and a printed circuit board arranged between the clamping elements. The force determining elastic elements are wave springs adapted to determine the force forcing the first and the second clamping elements 5 towards each other.

[0043] Surprisingly, using wave springs instead of the hitherto employed helical springs provides numerous advantages over the prior art, making the DMD assembly more compact and hence facilitating reducing the length of the cooling stud thereby effectively increasing its cooling capabilities. Wave springs offer a lower working height: Wave springs can achieve the same force and deflection as helical springs while occupying less space axially. The wave-shaped profile provides more consistent force distribution across the spring's surface area, and the wave design distributes stress more evenly, potentially increasing the spring's lifespan and 5 reliability.

[0044] While wave springs can be formed from various wire types, typically flat wire is preferred, which contributes not only to a compact profile and specific forcedeflection characteristics, but also positively affects factors such as the spring's 0 height, load capacity, and deflection properties. Flat wire construction allows for more consistent and predictable force distribution compared to round wire, but the optimal choice can depend on the specific application requirements.

[0045] The preferred flat profile of wave springs makes them easier to center in an

[0046] 5 assembly. The wider contact area of wave springs offers improved resistance to lateral movement. The wave pattern can be adjusted to achieve specific forcedeflection curves. Wave springs exhibit less tendency to resonate at certain frequencies compared to helical springs and offer improved vibration damping characteristics, which is particularly beneficial in DMD applications, where

[0047] 0 minimizing vibrations is crucial for maintaining image quality. The unique waveshaped profile of these springs helps absorb and dissipating vibrational energy more effectively. Due to their flatter profile and larger contact area, wave springs madeD / BARUXR-024-DE

[0048] B240005 Description

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[0050] from flat wire generally offer improved thermal conductivity and thus contribute to dissipate heat generated by a DMD in use.

[0051] Wave springs generally provide more precise and consistent force application 5 across their surface area. This uniform force distribution is advantageous for ensuring even pressure on the DMD, which may contribute to improved alignment stability and potentially enhance the overall optical performance of the device.

[0052] Moreover, wave springs and helical springs operate on different mechanical principles: Wave springs primarily rely on bending forces, while helical springs operate through torsional forces. When a load is applied to a wave spring, its waves begin to flatten, generating an upward force that allows for both axial and radial load transmission, which contributes to more consistent and predictable force application in a DMD mounting structure, enhancing the stability and reliability of the assembly. In contrast, helical springs twist as they compress, which results in not all force 5 being perfectly aligned with the axis. This twisting action during compression may, in some cases, lead to buckling of the helical spring.

[0053] The compact nature of wave springs allows for a reduction in the overall size of the DMD assembly. This size reduction leads to weight savings in the final assembly. 0

[0054] Wave springs may also offer greater design flexibility in some instances. Their unique shape allows for customization of spring characteristics, such as forcedeflection curves, by adjusting parameters like the number of waves, wave height, and material thickness. This adaptability enables fine-tuning of the mounting

[0055] 5 structure's performance to meet specific application requirements.

[0056] According to a preferred embodiment, the receptacles are threaded sleeves or threaded bores arranged on or in one of the first and the second clamping elements. This contributes to the compactness of the DMD assembly, since no separate 0 elements such as nuts are necessary. Moreover, threaded sleeves can advantageously have a double function and act as centering elements for other components.D / BARUXR-024-DE

[0057] B240005 Description

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[0059] According to another preferred embodiment, the wave springs are arranged between a screw head and a side of one of the clamping elements that in the mountain state faces away from the other clamping element. In that way, the wave springs act as washers preventing direct abrasive contact between the screw head 5 and the respective clamping element. While in principle the wave springs could also be arranged for example between the first and the second clamping elements, the preferred arrangement facilitates assembling since the wave springs may be put on the respective screws, and the screws may then easily be mounted holding the wave springs.

[0060] According to another preferred embodiment, the first clamping element may be a mounting plate having a DMD receptacle with an opening for exposing the mirrors of a DMD, and receptacles for receiving the screws. Surrounding the opening for exposing the mirrors, a recess or indentation for receiving the mounting surface area 5 of a DMD and centering the DMD may be provided. When the first clamping element is such mounting plate, the second clamping element may advantageously be a pressing plate having an opening to expose the side of an DMD opposite its mirrors and centering sleeves for each wave spring.

[0061] 0 According to another preferred embodiment, the second clamping element may further comprise a number of threaded sleeves or threaded bores for receiving mounting screws for attaching heat sink to the second clamping element. This provides another big advantage over the DMD mounting known from the aforementioned two prior art documents, which teach that the "attaching" screws, 5 i.e. the screws for attaching the heat sink, are screwed into the "clamping" screws, i.e. the screws for clamping together the first and the second clamping elements; when in such arrangement a clamping screw loosens, automatically the contact between the DMD's thermal interface area and the cooling stud loosens. Moreover, as the axes of a clamping screw and the respective attaching screw are coaxial, 0 effectivity elongating the clamping screws, high torque forces may act on the first clamping element.D / BARUXR-024-DE

[0062] B240005 Description

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[0064] The DMD assembly according to the invention may comprise a DMD, an interposer, and a printed circuit board arranged in that order between the first and the second clamping element.

[0065] 5 According to a preferred embodiment, the DMD assembly further comprises a heat sink attached to the second clamping element having a cooling stud in contact with a side of the DMD opposite its mirrors.

[0066] According to another preferred embodiment, the heat sink is a fluid-cooled heat sink.

[0067] Attaching a heat sink is attached may be done via mounting screws. In such case, force determining elastic elements may be arranged between a head of each mounting screw and the heat sink. These elastic elements may be wave springs or conventional helical springs, as the forces from the mounting screws to be

[0068] 5 determined by these elastic elements are, as explained above, are generally lower than those applied by the clamping screws and the length of the springs has no impact on the length of the cooling stud.

[0069] According to another preferred embodiment, in which the first clamping element is a 0 mounting plate, at least a first, preferably a first and second seal are arranged on one respectively on both sides of the mounting plate around the DMD. Such seals may prevent in particular dust particulates from entering the DMD assembly and affecting for example the printed circuit board or the DMD. The DMD may be glued to the mounting plate.

[0070] According to another preferred embodiment, the DMD and the side of the DMD facing the receptacle and / or the interposer and the side of the DMD facing the interposer and / or the printed circuit board and the side of the interposer facing the printed circuit board may be provided with centering protrusions and corresponding 0 recessions / openings, advantageously facilitating putting together the assembly.

[0071] According to another preferred embodiment, an insulating layer is provided between the second clamping element and the printed circuit board.D / BARUXR-024-DE

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[0074] Further advantages and details of the invention will become apparent from the following detailed description of preferred embodiments in conjunction with the drawing, which comprises six figures.

[0075] 5

[0076] BRIEF DESCRIPTION OF THE DRAWING

[0077] Fig. 1 shows is a perspective view of a DMD assembly according to one embodiment of the invention in the mounted state.

[0078] Fig. 2 is a top view onto the DMD assembly according to Fig. 1.

[0079] Fig. 3 is a sectional view along the line Ill-Ill in Fig. 2, seen along in the direction as indicated by the arrows iii in Fig. 2.

[0080] 5

[0081] Fig. 4 is a partially exploded of the DMD assembly according to Fig. 1.

[0082] Fig. 5 is a perspective view of a heat sink usable in another embodiment of the invention.

[0083] 0

[0084] Fig. 6 is another perspective view of the heat sink according to Fig. 5.

[0085] DESCRIPTION OF PREFERRED EMBODIMENTS

[0086] 5 In Figures 1 to 4, a DMD assembly 10 according to one embodiment of the invention is shown. It should be noted that in order to avoid overloading the figures, generally not all elements shown are provided with reference numbers. For example, when numerous identical screws, through holes, springs etc. are present, only some are provided with reference numbers.

[0087] 0

[0088] The assembly 10 comprises a mounting plate 12, acting as the first clamping element, and a pressing plate 14, acting as a second clamping element. Arranged between these clamping elements are a DMD 16, a first seal 18, an interposer 20D / BARUXR-024-DE

[0089] B240005 Description

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[0091] and a printed circuit board 22. The first seal 18 surrounds the DMD 16 and has an opening 24 substantially complementary in shape and size to the parts of the DMD it surrounds.

[0092] 5 The assembly 10 further comprises a heat sink denoted in its entirety by 26. In the embodiment shown in figures 1 to 4, the heat sink is a liquid-cooled and comprises a cooling plate 28 with a cooling stud 30 and a cooling element 32 attached to the cooling plate and adapted to circulate a cooling liquid entering and leaving the cooling element 32 via perspective spigots 34, 36. The cooling plate 28 as a double function and provides not only the cooling stud 30 and hence the thermal contact to the DMD 16, but has a number of through holes 38, allowing mounting screws 40 to pass through the cooling plate 28 to respective threaded sleeves 42 provided on the pressing plate 14 while providing abutment surfaces for helical springs 44 used to determine the forces provided by the screws 40 pressing via their screw heads the 5 helical springs against the cooling plate 28 and hence the cooling stud 30 against the DMD 16. In the shown embodiment, helical springs 44 are used, but depending on the overall design needs wave springs might be used as well.

[0093] Besides the threaded sleeves 42, the pressing plate 14 also comprises centering 0 sleeves 46 for aligning wave springs 48. The centering sleeves 46 are arranged around respective through holes allowing clamping screws 50 to pass through the pressing plate 14. The surface of the pressing plate 14 surrounding the centering sleeves 46 acts as abutment surface for one end of each wave spring 48, while the heads 52 of the clamping screws 50 provide abutment surfaces for the opposite 5 ends of each wave spring 48. So-called shoulder screws 50 are used as clamping screws, their heads 52 making washers unnecessary and thus further contributing to reducing the height of the mounting assembly. The printed circuit board 22 is also provided with respective through holes 54, allowing the screws 50 to pass to respective threaded sleeves 56 provided on the mounting plate 12 for receiving the 0 screws 50.

[0094] Besides the threaded sleeves 56, the mounting plate 12 comprises a receptacle 56 for receiving and aligning the DMD 16. The receptacle 58 is provided with anD / BARUXR-024-DE

[0095] B240005 Description

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[0097] opening 60 to expose the mirrors of the DMD 16. Surrounding the opening 60 in the receptacle 58 is an abutment surface 62 that effectively presses against the mounting surface area surrounding the mirrors of the DMD 16. The DMD 16 may be glued to the mounting plate 12, which could render a separate seal superfluous. 5

[0098] Although not shown in the schematic drawings, the DMD 16 comprises on its side opposite the mirrors an electrical surface area acting as a counterpart for the mounting surface area and surrounding a thermal interface area, against which the cooling stud 30 is pressed. The electrical surface area is provided with a number of electrical contacts, and the interposer 20 is designed to come into contact with these electrical contacts and in turn connecting them to the printed circuit board 22. To ensure proper alignment of the interposer 20 and the DMD 16, the DMD is provided with a number of recessions 64 while the interposer 20 is provided with corresponding centering protrusions (not visible in the drawings). Similarly, for 5 alignment with the interposer 20, the printed circuit board 22 is provided with a number of openings 66 while the interposer 20 is provided with corresponding centering protrusions 68. In use, the screws 50 are screwed into the threaded sleeves 56, the screw heads 52 pressing the wave springs 48 against the pressing plate 14, which in turn is pressed towards mounting plate 12, thus clamping together 0 the elements arranged between mounting plate 12 and pressing plate 14. As the spring rate is known, the force applied unto the pressing plate 14 and thus in particular unto the electrical surface area and the mounting surface area of the DMD 16 can be determined and hence applied in a controlled manner. In a typical application with a typical DMD, wave springs with a spring rate of about 12 to 15 5 N / mm may be used, having a working height (length between screw head 52 and abutment surface on pressing plate 14) of about 2 to 4 mm to apply the wanted forces. A typical helical spring for achieving the same forces would have a spring rate of about 20 to 25 N / mm and a working height of about 8 to 10 mm, hence rendering the assembly much thicker and requiring a much longer cooling stud. 0

[0099] The printed circuit board 22 is provided with electronic circuitry 70 and electrical connectors 72, only some of which have been provided with reference numbers.D / BARUXR-024-DE

[0100] B240005 Description

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[0102] To allow the cooling stud 30 to pass through unto the DMD 16, or to be precise unto its thermal interface area, the pressing plate 14 is provided with an opening 74, the printed circuit board 22 is provided with an opening 76, and the interposer 20 is provided with an opening 78. As probably best seen in Fig. 3, the inventive

[0103] 5 arrangement using wave springs 48 enables a very compact design of the DMD assembly and in particular a very low height between the mounting plate 12 and the pressing plate 14, which in turn allows the cooling stud 30 to be as short as possible, hence limiting its thermal resistance and improving the cooling of the DMD 16.

[0104] In the shown embodiment, the DMD assembly 10 also comprises a second seal 80 attached to the mounting plate 12 from the side opposite the receptacle 58. Such seal might 80 be provided with a self-adhesive surface for attaching it to the mounting plate 12, and comprises an opening 82 for exposing the mirrors of the 5 DMD 16. The mounting plate comprises a number of through holes 84 for mounting the DMD assembly 10 to other parts of an apparatus employing the assembly such as in particular a DLP projector.

[0105] Figures 5 and 6 show in two different perspective views a heat sink 86, which could 0 be used in an embodiment of the invention. This heat sink 86 is not liquid-cooled and comprises a number of heat exchange plates 88 in contact with the surrounding air. It should be noted that in the shown exemplary embodiment of a heat sink 86 the openings 90 for mounting screws and the orientation of the cooling stud 92 must of course be adapted to the position and orientation of the threaded sleeves 42 and 5 the openings 74, 76 and 78 when such heat sink 86 shall be used instead of the heat sink 26 in an assembly as shown in Fig. 4.D / BARUXR-024-DE

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[0108] LIST OF REFERENCE NUMBERS

[0109] 10 DMD Assembly

[0110] 12 first clamping element (mounting plate) 14 second clamping element (pressing plate) 16 DMD

[0111] 18 first seal

[0112] 20 interposer

[0113] 22 printed circuit board

[0114] 24 opening

[0115] 26 heat sink

[0116] 28 cooling plate

[0117] 30 cooling stud

[0118] 32 cooling element

[0119] 34 spigot

[0120] 36 spigot

[0121] 38 through holes

[0122] 40 mounting screw

[0123] 42 threaded sleeve

[0124] 44 helical spring

[0125] 46 centering sleeve

[0126] 48 wave spring

[0127] 50 clamping screw

[0128] 52 head of screw

[0129] 54 through hole

[0130] 56 threaded sleeve

[0131] 58 receptacle

[0132] 60 opening

[0133] 62 abutment surface

[0134] 64 recession

[0135] 66 opening

[0136] 68 centering protrusion

[0137] 70 electronic circuitryD / BARUXR-024-DE

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[0140] 72 electrical connector 74 opening

[0141] 76 opening

[0142] 78 opening

[0143] 80 second seal

[0144] 82 opening

[0145] 84 through hole

[0146] 86 heat sink

[0147] 88 heat exchange plate 90 opening

[0148] 92 cooling stud

Claims

D / BARUXR-024-DEB240005 Description- 15 -CLAIMSA digital micro-mirror device (DMD) assembly , comprisinga first clamping element (12) and a second clamping element (14), the 5 clamping elements adapted to receive between them at least a DMD (16), an interposer (20), and a printed circuit board (22),a number of screws (50) and corresponding receptacles (56) for forcing the first and the second clamping elements towards each other to fixedly clamp together at least a DMD, an interposer and a printed circuit board,force determining elastic elements arranged between each screw and each receptacle in order to determine the force forcing the first and the second clamping elements towards each other,characterized in thatthe elastic elements are wave springs (48).

52. The DMD assembly according to claim 1, characterized in that the receptacles are threaded sleeves or threaded bores (56) arranged on or in one of the first and the second clamping elements.0 3. The DMD assembly according to claim 1 or 2, wherein the wave springs (48) are arranged between a screw head (52) and a side of one of the clamping elements that in the mountain state faces away from the other clamping element.

4. The DMD assembly according to one of claims 1 to 3, wherein the first 5 clamping element is a mounting plate (12) havinga DMD receptacle (58) with an opening (60) for exposing the mirrors of a DMD, andreceptacles (56) for receiving the screws.0 5. The DMD assembly according to claim 4, wherein the second clamping element is a pressing plate (14) having an opening (74) to expose the side of an DMD opposite its mirrors and centering sleeves (46) for each wave spring.D / BARUXR-024-DEB240005 Description- 16 -6. The DMD assembly according to one of claim 1 to 5, wherein the second clamping element further comprises a number of threaded sleeves or threaded bores (42) for receiving mounting screws (40) for attaching heat sink to the second clamping element.

57. The DMD assembly (10) according to one of claims 1 to 6, further comprising:a DMD (16), an interposer (20), and a printed circuit board (22) arranged in that order between the first and the second clamping element.

8. The DMD assembly (10) according to claim 7, further comprising a heat sink (26) attached to the second clamping element having a cooling stud (30) in contact with a side of the DMD opposite its mirrors.5 9. The DMD assembly (10) according to claim 8, wherein the heat sink is a fluid-cooled heat sink (26).

10. The DMD assembly (10) according to claim 8 or 9 and claim 6, wherein the heat sink is attached to the pressing plate via mounting screws (40), further 0 comprising force determining elastic elements (44) arranged a head of each mounting screw and the heat sink.

11. The DMD assembly (10) according to one of claims 7 to 10 and claim 4, further comprising at least a first, preferably a first (18) and second seal (80) arranged on one respectively on both sides of the mounting plate around the DMD.

12. The DMD assembly (10) according to one of claims 7 to 11 and claim 4, whereinthe DMD and the side of the DMD facing the receptacle and / or0 the interposer and the side of the DMD facing the interposer and / orthe printed circuit board and the side of the interposer facing the printed circuit boardD / BARUXR-024-DEB240005 Description- 17 -are provided with centering protrusions (68) and corresponding recessions / openings (64, 66).

13. The DMD assembly (10) according to one of claims 7 to 12 and claim 4, 5 wherein the DMD is glued to the mounting plate.

14. The DMD assembly (10) according to one of claims 7 to 13, further comprising an insulating layer between the second clamping element and the printed circuit board.

015. A DLP projector comprising a DMD assembly (10) according to one of claims 1 to 14.

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