Optical assembly, optical device and associated manufacturing process
The optical assembly with a shoulder and confined fixing joint addresses overflow and non-uniformity issues, ensuring optimal performance and hermeticity by containing the bonding agent, thus improving the optical device's reliability.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- THALES SA
- Filing Date
- 2024-12-09
- Publication Date
- 2026-06-12
AI Technical Summary
Existing optical assemblies face issues with overflow of solder or adhesive onto optical areas, leading to reduced field of view and non-uniform assembly joints that compromise hermeticity and reliability.
An optical assembly design featuring a support with an opening and an optical filter having a shoulder, with a fixing joint confined between the shoulder and the support, ensuring uniform distribution of the bonding agent and preventing overflow onto optical zones.
The design achieves optimal optical performance and hermeticity by containing the bonding agent within the fixing joint, enhancing the assembly's uniformity and airtightness.
Smart Images
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Abstract
Description
Title of the invention: Optical assembly, optical device and associated manufacturing process
[0001] The present invention relates to an optical assembly, in particular comprising an optical filter and a support.
[0002] In many optical devices, such as optical detectors for example, it is common to assemble an optical filter and a support intended to encapsulate at least one optoelectronic component.
[0003] The optical filter is generally a planar optical filter comprising two optical zones facing each other and giving particular optical properties to the optical flow passing through them.
[0004] Such an optical filter is generally assembled to a metal support by gluing or brazing.
[0005] However, such an assembly is generally unsatisfactory.
[0006] Indeed, there is a risk of the solder or adhesive bonding the filter to the substrate overflowing, particularly on one of the optical areas. Such overflow limits the field of view of the optical device, and in particular that of the encapsulated optoelectronic component, and thus leads to a reduction in its performance.
[0007] Furthermore, there is a risk of non-uniformity in the assembly joint, which can lead to a lack of hermeticity or sealing of the optical device. This can, in particular, have negative consequences on the lifespan and reliability of the encapsulated optoelectronic components.
[0008] The aim of the invention is therefore to overcome these drawbacks, and in particular to offer an optical assembly with a satisfactory assembly between the optical filter and the support.
[0009] To this end, the invention relates to an optical assembly comprising: - a support including an opening; - an optical filter defining at least one optical zone and including a shoulder, with at least one optical zone of the filter facing the aperture of the support; and - a fixing joint for the optical filter in the support, the fixing joint being confined between the shoulder and the support.
[0010] The shoulder formed on the optical filter allows the fixing joint to be contained and thus prevents it from protruding, thereby ensuring optimal optical performance. Furthermore, during the assembly of the optical filter in the support, The shoulder allows for a uniform fixing joint and therefore guarantees the airtightness of the optical assembly thus obtained.
[0011] According to other advantageous aspects of the invention, the optical assembly comprises one or more of the following features, taken individually or in all technically possible combinations:
[0012] - The shoulder is defined outside of at least one optical zone.
[0013] - The optical filter comprises an upper face and a lower face opposite each other one from the other, each of the upper and lower faces comprising an optical zone.
[0014] - The optical filter comprises an upper portion extending between the face upper and shoulder and a lower portion extending between the shoulder and the lower face.
[0015] - The fixing joint is formed by the solidification of a bonding agent confined between the shoulder and the support.
[0016] - The support comprises an upper wall in which the opening is defined, one of the optical zones of the optical filter extending in continuity with the upper wall.
[0017] The invention also relates to an optical device comprising an optical assembly as described above.
[0018] The invention also relates to a method for manufacturing an optical assembly comprising the following steps: a. provision of a support, including an aperture and an optical filter defining at least one optical zone; b. definition of a shoulder on the optical filter; c. arrangement of the optical filter in the support so that the optical area of the optical filter is opposite the opening of the support; and d. formation of a fixing joint by the solidification of a bonding agent confined between the shoulder and the support.
[0019] According to other advantageous aspects of the invention, the manufacturing process comprises one or more of the following features, taken individually or in all technically possible combinations:
[0020] - Step d) includes distributing the binding agent in liquid form onto the shoulder.
[0021] - Step b) is carried out by laser or mechanical cutting.
[0022] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:
[0023] [Fig. 1] [Fig. 1] is a schematic representation of an optical device according to a particular embodiment of the invention; and
[0024] [Fig.2] [Fig.3] Figures 2 and 3 are schematic representations of different stages of a manufacturing process for an optical assembly according to the invention.
[0025] Fig. 1 shows an optical device 10 comprising an optical assembly 12.
[0026] The optical device 10 includes, for example, an optoelectronic component 14.
[0027] The optoelectronic component 14 is in particular a photodiode.
[0028] In the particular embodiment of [Fig.1], the optical device 10 is an optical detector.
[0029] As illustrated in [Fig.2], the optical assembly 12 includes a support 16, an optical filter 18 and a fixing joint 20.
[0030] In particular, in the particular embodiment of [Fig.1], the optical assembly 12 defines a filtered hood of the optical detector 10, in particular encapsulating the optoelectronic component 14.
[0031] For example, in the particular embodiment of [Fig.1], the support 16 defines the cover of the optical detector 10.
[0032] More specifically, the support 16 comprises an upper wall 22 and a peripheral wall 24.
[0033] In the embodiments illustrated in the Figures, the upper wall 22 is substantially circular and the peripheral wall 24 is cylindrical.
[0034] Alternatively, the upper wall 22 has a rectangular shape, and for example a square one.
[0035] The upper wall 22 has for example a transverse dimension, for example a diameter, between 1 mm and 5 cm.
[0036] The upper wall 22 has for example a thickness extending between an inner face 23 and an outer face 25 of between 0.1 mm and 2 mm.
[0037] The support 16 is, for example, metallic, in particular made of iron / nickel / cobalt.
[0038] As can be seen in [Fig. 2], the support 16 includes an opening 26.
[0039] In the particular embodiment of [Fig.1], the opening 26 is defined in particular with regard to the optoelectronic component 14, so as in particular to define the field of view (illustrated in dotted lines on [Fig.1]) of said component 14.
[0040] In particular, the opening 26 is defined on the upper wall 22 of the support 16.
[0041] More precisely, the opening 26 is through, that is to say it extends from the external face 25 to the internal face 23.
[0042] The opening 26 is for example a circular opening, in particular with a diameter between 0.5 mm and 4 cm.
[0043] Alternatively, the opening 26 is, for example, a rectangular opening.
[0044] The optical filter 18 is, for example, a device that allows a portion of the incident optical flux to pass through. The outgoing optical flux, for example, has optical properties different from the incident optical flux. The path of the optical flux is, for example, modified at the interfaces of the optical filter 18.
[0045] For example, the optical filter 18 is an absorption optical filter, which for example transmits or absorbs part of the optical flux depending on its wavelength.
[0046] The optical filter 18 is for example made of glass, for example treated glass or colored glass, of Silicon or of Germanium.
[0047] In particular, the optical filter 18 defines at least one optical zone 28, that is to say, an area of incidence and / or exit of the optical flux.
[0048] For example, the optical filter 18 is a plane filter.
[0049] Alternatively, the optical filter 18 is a domed filter.
[0050] More specifically, the optical filter 18 comprises an upper face 30 and a lower face 32 facing each other. The lower face 32 is, for example, oriented towards the interior of the optical device 10 and the upper face 30 towards the exterior.
[0051] In particular, each of the upper face 30 and lower face 32 includes an optical zone 28.
[0052] More specifically, the optical filter 18 is adapted so that an optical flux passes through said filter 18 from one face 30, 32 to the other.
[0053] In other words, the optical filter 18 is configured so that an optical flow enters through the optical zone 28 of one of the upper 30 and lower 32 faces and exits through the optical zone 28 of the other of the upper 30 and lower 32 faces with different optical properties.
[0054] In the particular embodiment of [Fig.1] with the optical device 10, the optical flux from outside enters through the optical zone 28 of the upper face 30, passes through the optical filter 18 and exits through the optical zone 28 of the lower face 32 towards the optoelectronic component 14.
[0055] In the preferred embodiment illustrated, the upper 30 and lower faces 32 have a substantially circular shape. The optical zone 28 of each of the upper 30 and lower 32 faces preferably also has a circular shape.
[0056] Alternatively, the upper 30 and lower 32 faces have a substantially rectangular shape, particularly in the case where the upper wall 22 also has a rectangular shape. In this case, the optical zone 28 of each of the upper 30 and lower 32 faces preferably also has a rectangular shape.
[0057] In particular, each optical zone 28 extends over the entirety of the corresponding upper face 30 or lower face 32.
[0058] The optical filter 18 includes a shoulder 34.
[0059] In particular, the optical filter 18 comprises an upper portion 36 extending between the upper face 30 and the shoulder 34 and a lower portion 38 extending between the shoulder 34 and the lower face 32.
[0060] Advantageously, as can be seen in [Fig.2], the transverse dimension of the upper portion 36 is less than that of the lower portion 38, so that the shoulder 34 defines a bearing surface 33, in particular oriented towards the upper face 30.
[0061] The bearing surface 33 is for example substantially parallel to each of the upper face 30 and the lower face 32 of the optical filter 18.
[0062] More specifically, in the illustrated embodiment, the shoulder 34 is composed in particular of the bearing surface 33, which defines the upper face of the lower portion 38 of the filter 18, and a step defined by the peripheral wall of the upper portion 36. The bearing surface 33 is, for example, perpendicular to the step. In the particular embodiment illustrated in the Figures, each of the upper portion 36 and the lower portion 38 is cylindrical.
[0063] In particular, the diameter of the upper portion 36 is less than that of the lower portion 38.
[0064] More specifically, the bearing surface 33 is annular.
[0065] Preferably, the shoulder 34 is defined outside the optical zone 28 of each of the upper 30 and lower 32 faces.
[0066] Preferably, in the embodiment illustrated in the Figures, the shoulder 34 is defined on the entire perimeter of the optical zone 28 of the upper face 30, and more precisely on the perimeter of the upper face 30.
[0067] For example, the upper portion 36 has a diameter between 0.5 mm and 4 cm and the lower portion 38 has a diameter between 0.6 mm and 4.1 cm.
[0068] Preferably, the upper portion 36 has a diameter substantially equal to that of the opening 26 provided in the support 16.
[0069] In particular, when the optical assembly 12 is assembled, at least a part of the upper portion 36, and in particular the upper face 30 of the optical filter 18, and more specifically its optical area 28, extends into the opening 26 of the support 16, as can be seen in particular in [Fig.2].
[0070] More specifically, the bearing surface 33 defined by the shoulder 34 extends opposite the inner face 23 of the upper wall 22 of the support 16.
[0071] Advantageously, the optical zone 28 of the upper face 30 of the optical filter 18 extends in continuity with the upper wall 22 of the support 16, and in particular with its external face 25, which makes it possible to optimize the field of view of the optoelectronic component 14 as can be seen in particular in [Fig.1].
[0072] The fixing joint 20 fixes the optical filter 18 in the support 16.
[0073] More specifically, the fixing joint 20 extends between the shoulder 34 formed on the optical filter 18 and the support 16.
[0074] More specifically, the fixing joint 20 extends between the bearing surface 33 defined by the shoulder 34 and the inner face 23 of the upper wall 22 of the support 16.
[0075] Advantageously, the fixing joint 20 extends over the entire bearing surface 33 defined by the shoulder 34.
[0076] In a particular embodiment illustrated in the Figures, the fixing joint 20 has an annular shape, in particular extending over the entire annular bearing surface 33 of the shoulder 34.
[0077] The fixing joint 20 is formed by the solidification of a binding agent 40 confined between the shoulder 34 and the support 16, and in particular between the bearing surface 33 defined by the shoulder 34 and the inner face 23 of the upper wall 22 of the support 16.
[0078] By solidification, we mean, here, the change from the liquid or viscous state to the solid state.
[0079] More specifically, as will be explained in more detail below, during the assembly of the optical filter 18 in the support 16, the binding agent 40 in liquid form, for example deposited on the bearing surface 33 of the shoulder 34, solidifies, for example by cooling or by heating, between the bearing surface 33 of the shoulder 34 and the inner face 23 of the upper wall 22 of the support 16.
[0080] The bonding agent 40 is for example chosen from a solder or an adhesive.
[0081] For example, the bonding agent 40 is a high-temperature hard solder, for example made of tin, silver, copper or lead.
[0082] Alternatively, the bonding agent 40 is a liquid adhesive, in particular a silicone or an epoxy resin.
[0083] According to another variant, the bonding agent 40 is a low-temperature flexible solder, for example indium.
[0084] According to another variant, the bonding agent 40 is a glass sealant, for example in the form of a glass preform.
[0085] A method for manufacturing such an optical assembly 12 will now be described.
[0086] The process includes a first step a) of providing a support 16 and a raw 18A optical filter.
[0087] The supplied support 16 includes an opening 26.
[0088] Preferably, the support 16 is as described above.
[0089] In particular, the support 16 comprises an upper wall 22 defining a inner face 23 and an outer face 25, the opening 26 being provided on said upper wall 22.
[0090] The supplied raw optical filter 18A defines at least one optical zone 28.
[0091] In particular, the raw optical filter 18A supplied is a planar optical filter comprising an upper face 30 and a lower face 32 facing each other, in particular each defining an optical zone 28.
[0092] Preferably, the raw 18A optical filter is substantially cylindrical, as can be seen in [Fig.2].
[0093] The process then includes a step b) of defining a shoulder 34 on the raw optical filter 18A, in particular so as to define the optical filter 18 as described above.
[0094] Preferably, this step b) is carried out by laser cutting.
[0095] Alternatively, this step b) is carried out by mechanical cutting, in particular by milling.
[0096] In particular, the raw optical filter 18A is cut so as to define the shoulder 34 with the bearing surface 33, in particular substantially parallel to each of the upper face 30 and the lower face 32.
[0097] For example, the raw optical filter 18A is cut so as to reduce the diameter only over a part of its height, and thus define the upper portion 36 as described above.
[0098] The process then includes a step c) of arranging the optical filter 18 and a binding agent 40 in the support 16.
[0099] In particular, as can be seen in [Fig.3], the optical filter 18 is arranged in the support 16, so that the optical area 28 of its upper face 30 is opposite the opening 26 of the support 16, and more specifically that the bearing surface 33 of the shoulder 34 of the optical filter 18 is opposite the inner face 23 of the upper wall 22 of the support 16.
[0100] As can be seen in the next step in [Fig.3], the bonding agent 40 is inserted between the optical filter 18 and the support 16, and more precisely between the bearing surface 33 of the shoulder 34 of the optical filter 18 and the inner face 23 of the upper wall 22 of the support 16.
[0101] In particular, the binding agent 40 in liquid form, which is for example an adhesive, is deposited between the bearing surface 33 of the shoulder 34 of the optical filter 18 and the inner face 23 of the upper wall 22 of the support 16.
[0102] The process then includes a step d) of forming a fixing joint 20 by solidification of the binding agent 40 confined between the shoulder 34 and the support 16.
[0103] Advantageously, the step formed by the shoulder 34, i.e. the difference in height between the bearing surface 33 of the shoulder 34 and the upper face 30 of the optical filter 18, confines the binding agent 40 between the shoulder 34 and the support 16, and in particular between the bearing surface 33 of the shoulder 34 of the optical filter 18 and the inner face 23 of the upper wall 22 of the support 16.
[0104] In particular, during step d), the binding agent 40 in liquid form is distributed in the shoulder 34, for example following pressure exerted between the optical filter 18 and the upper wall 22 of the support 16
[0105] More specifically, due to the confinement of the binding agent 40 by the shoulder 34, the binding agent 40 in liquid form moves in the shoulder 34, in particular between the bearing surface 33 of the shoulder 34 of the optical filter 18 and the inner face 23 of the upper wall 22 of the support 16. This movement leads in particular to a distribution of the binding agent 40 along the shoulder, and preferably in a uniform manner.
[0106] As illustrated in [Fig.3], the binding agent 40 is advantageously distributed over the entire circumference of the shoulder 34.
[0107] Following this distribution of the binding agent 40, it is solidified so as to form the fixing joint 20.
[0108] This solidification is achieved for example by cooling, by reducing the pressure and / or by drying.
[0109] Such an optical assembly 12 is particularly advantageous and makes it possible in particular to obtain a satisfactory assembly of the optical filter 18 in the support 16.
[0110] In particular, the shoulder 34 provided on the optical filter 18 makes it possible to confine the binding agent 40 between the bearing surface 33 of the shoulder 34 of the optical filter 18 and the inner face 23 of the upper wall 22 of the support 16, and therefore out of the optical zones 28 of the optical filter 18.
[0111] Such a shoulder 34 therefore prevents the binding agent 40 from overflowing onto the optical zone(s) 28, which ensures optimal optical performance.
[0112] Furthermore, during the assembly of the optical filter 18 in the support 16, the shoulder 34 distributes the binding agent 40 uniformly between the bearing surface 33 of the shoulder 34 of the optical filter 18 and the inner face 23 of the upper wall 22 of the support 16.
[0113] Such a distribution makes it possible to obtain a uniform fixing joint 20 and therefore to guarantee the hermeticity of the optical assembly 12 thus obtained.
[0114] Moreover, such a spreading distribution of the binding agent 40 makes it possible to optimize the quantity of binding agent 40 used.
[0115] In addition, in the particular case where there is a flushness of the optical filter 18 with the support 16, a gain on the field of view of the component can also be obtained, due in particular to the difference in index between the optical filter 18 and its external environment.
[0116] In a variant of the invention (not illustrated), the transverse dimension of the upper portion 36 of the filter 18 is, for example, greater than that of the lower portion 38, so that the bearing surface 33 of the shoulder 34 is in particular oriented towards the lower face 32.
[0117] In this variant, the shoulder 34 is notably composed of the bearing surface 33, in particular which defines the lower face of the upper portion 36 of the filter 18, and of a step defined by the peripheral wall of the lower portion 38. The bearing surface 33 is for example perpendicular to the step.
[0118] In this variant, the optical filter 18 is arranged in the support 16, so that the optical area of its lower face 32 is opposite the opening 26 of the support 16, and more specifically that the bearing surface 33 of the shoulder 34 of the optical filter 18 is opposite the external face 25 of the upper wall 22 of the support 16.
[0119] In another embodiment of the invention, the binding agent 40 is in solid form when arranged between the support 16 and the optical filter 18 in step c).
[0120] For example, in this particular embodiment, the bonding agent 40 is a hard solder or a glass sealant, for example in the form of a preform.
[0121] In such an embodiment, the process includes a step of melting the binding agent 40, so that it passes into the liquid state, between step c) and step d).
[0122] This melting step is for example carried out by heating and / or by increasing pressure.
Claims
Demands
1. Optical assembly (12) comprising: a. a support (16) including an aperture (26); b. an optical filter (18) defining at least one optical zone (28) and including a shoulder (34), the at least one optical zone (28) of the filter (18) being opposite the aperture (26) of the support (16); and c. a fixing joint (20) of the optical filter (18) in the support (16), the fixing joint (20) being confined between the shoulder (34) and the support (16).
2. Optical assembly (12) according to claim 1, wherein the shoulder (34) is defined outside of at least one optical zone (28).
3. Optical assembly (12) according to claim 1 or 2, wherein the optical filter (18) comprises an upper face (30) and a lower face (32) facing each other, each of the upper (30) and lower (32) faces comprising an optical zone (28).
4. Optical assembly (12) according to claim 3, wherein the optical filter (18) comprises an upper portion (36) extending between the upper face (30) and the shoulder (34) and a lower portion (38) extending between the shoulder (34) and the lower face (32).
5. Optical assembly (12) according to any one of claims 1 to 4, wherein the fixing joint (20) is formed by the solidification of a binding agent (40) confined between the shoulder (34) and the support (16).
6. Optical assembly (12) according to any one of claims 1 to 5, wherein the support (16) comprises an upper wall (22) in which the aperture (26) is defined, one of the optical zones (28) of the optical filter extending in continuity with the upper wall (22).
7. Optical device (10) comprising at least one optical assembly (12) according to any one of claims 1 to 6.
8. A method for manufacturing an optical assembly (12) comprising the following steps:
9.
10. a. supply of a support (16), comprising an opening (26) and an optical filter (18) defining at least one optical zone (28); b. definition of a shoulder (34) on the optical filter (18); c. arrangement of the optical filter (18) in the support (16) such that the optical area (28) of the optical filter (18) is opposite the opening (26) of the support (16); and d. formation of a fixing joint (20) by the solidification of a binding agent (40) confined between the shoulder (34) and the support (16). Manufacturing method according to claim 8, wherein step d) comprises distributing the binding agent (40) in liquid form onto the shoulder (34). Manufacturing method according to claim 8 or 9, wherein step b) is carried out by laser or mechanical cutting.