Lighting module for a motor vehicle

Abstract

The invention relates to a lighting module (1) for a motor vehicle, characterised in that it comprises: - a housing (2), - at least one printed circuit board (4A, 4B) to which at least one light source (5A, 5B) is attached, - a primary lens (6) intended to shape a light beam produced by the at least one light source, and - a heat sink (7) intended to dissipate the heat produced by the lighting module, the primary lens being held clamped between the housing and the heat sink.

Description

Light module for a motor vehicle Technical field of the invention

[0001] The invention relates to a light module for a motor vehicle. State of the prior art

[0002] Light modules for motor vehicles generally provide lighting and / or signaling functions. Light modules generally comprise a housing accommodating at least one light source and an optical lens configured to shape a light beam produced by the at least one light source. In order to produce a light beam of a very specific shape and correctly positioned in space, the at least one light source and the optical lens must be positioned, oriented and fixed with great precision. Otherwise, the light beam produced by the light module may not effectively illuminate the vehicle's surroundings, and / or dazzle other road users, and / or project light patterns with blurred contours.

[0003] The method of fixing the optical lens can also lead to disruption of the light beam coming from the optical module. Indeed, in certain circumstances, the fixing means used generate mechanical stresses and deformations of the optical lens. These stresses and / or deformations lead to deflecting the light rays along undesired trajectories, and therefore to degrading the lighting function performed by the light module.

[0004] Furthermore, the light modules known from the state of the art generally include many parts to be assembled. Their manufacturing process is therefore relatively complex. These light modules are also heavy and bulky. Presentation of the invention

[0005] The aim of the invention is to provide a light module which overcomes the above drawbacks and improves the light modules known from the prior art.

[0006] More specifically, a first object of the invention is a light module that is simple to manufacture and comprises an optical lens fixed in such a way as to avoid any stress and / or deformation of the optical lens.

[0007] The invention relates to a light module for a motor vehicle, the light module comprising:- a housing,- at least one printed circuit board on which at least one light source is fixed,- a primary lens intended to shape a light beam produced by the at least one light source, and- a heat sink intended to dissipate heat produced by the light module, the primary lens being held between the housing and the heat sink.

[0008] The heat sink may be secured to the housing by a set of securing screws, and the primary lens may include a set of apertures, at least one securing screw passing through at least one aperture of the primary lens.

[0009] Said fixing screws may be without contact with the primary lens.

[0010] The at least one printed circuit board may be held sandwiched between the housing and the heat sink, with one face of the at least one printed circuit board directly abutting the primary lens.

[0011] The primary lens may include at least two first centering elements cooperating with the at least one printed circuit board to position the primary lens relative to the at least one printed circuit board.

[0012] The heat sink may include at least two second centering members cooperating with the at least one printed circuit board to position the heat sink relative to the at least one printed circuit board.

[0013] The primary lens can be a monolithic element made of transparent plastic, and it can be obtained by molding.

[0014] The at least one light source may comprise at least one first light source and at least one second light source, the primary lens being configured to shape a light beam produced by the at least one first light source to produce a first light function, in particular a light function of the dipped beam type, the primary lens being configured to shape a light beam produced by the at least one second light source to produce a second light function, in particular a light function of the high beam type.

[0015] The primary lens may comprise at least one first input diopter intended to receive light rays produced by the at least one first light source, at least one second input diopter, distinct from the at least one first input diopter and intended to receive light rays produced by the at least one second light source, and a single output diopter through which the light rays produced by the at least one first light source and by the at least one second light source are intended to exit the primary lens.

[0016] The primary lens may comprise a first reflection surface and a second reflection surface, at least a portion of the light rays produced by the at least one light source being intended to be reflected on the first reflection surface and then on the second reflection surface before exiting the primary lens. Presentation of figures

[0017] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of a particular embodiment made without limitation in relation to the attached figures among which:

[0018] This is a first perspective view of a light module according to one embodiment of the invention.

[0019] This is a second perspective view of the light module.

[0020] This is a third perspective view of the light module, with a housing and secondary lens of the light module obscured.

[0021] This is a fourth perspective view of the light module, with the light module housing and secondary lens hidden.

[0022] This is a perspective view of two printed circuit boards each with light sources and a heat sink for the light module of the.

[0023] This is a perspective view of a heat sink plate of the light module of the.

[0024] This is a first perspective view of a primary lens of the light module of the.

[0025] This is a second perspective view of the primary lens of the light module of the.

[0026] This is a first sectional view along a longitudinal and vertical plane of a part of the light module of the.

[0027] This is a second sectional view along a longitudinal and vertical plane of a part of the light module of the.

[0028] This is a perspective view of a light module housing. Detailed description

[0029] Figures 1 and 2 schematically illustrate a light module 1 according to one embodiment of the invention. The light module 1 is intended to be integrated into the front of a motor vehicle to perform a function of lighting the environment of the vehicle. The light module 1 is in particular intended to produce a dipped beam type light beam, allowing the lighting of the environment in front of the vehicle without dazzling motorists traveling in the opposite direction. The light module 1 is also intended to produce a high beam type light beam allowing more powerful, and more distant lighting of the environment in front of the vehicle, when no other motorist is traveling in the opposite direction.

[0030] Alternatively, the invention could also be transposed to a light module intended to perform a different lighting function and / or a signaling function, and / or to a light module arranged at the rear or on the sides of a motor vehicle.

[0031] In this description and in the figures, the X axis designates the longitudinal axis of the vehicle. When moving forward and in a straight line, the vehicle moves from the rear to the front in a direction parallel to its longitudinal axis. The X axis is oriented from the front to the rear of the vehicle, that is to say in the direction of reverse travel. The Y axis designates the transverse axis of the vehicle. The Y axis is oriented from left to right, left and right being defined according to the point of view of a driver of the vehicle. The Z axis designates the axis perpendicular to the X axis and the Y axis. The vehicle is considered to be resting on horizontal ground. The Z axis is a vertical axis, oriented from bottom to top. The X, Y and Z axes form an orthogonal reference frame. This same reference frame, defined with reference to a vehicle, will also be used to describe the light module 1, even considered outside the vehicle, since it is intended to be mounted in a specific orientation in the vehicle.

[0032] The light module 1 comprises a housing 2, also called a casing, forming a protective envelope around the various components of the light module 1. In particular, the light module is fixed to the vehicle via its housing 2. For this purpose, the housing comprises a set of fixing holes 3 intended to cooperate with fixing screws. The fixing holes 3 are in particular fixing wells and are arranged on a rear face of the housing 2. The fixing wells extend parallel to the X axis.

[0033] The housing 2 is advantageously a monolithic element, made of plastic, in particular obtained by molding. It comprises in particular a lower wall, an upper wall and side walls. It also comprises a front opening through which light rays can be emitted, and a rear opening allowing, among other things, the assembly of different components within it.

[0034] In addition to the housing 2, the light module 1 comprises at least one printed circuit board 4A, 4B on which at least one light source 5A, 5B is fixed, a primary lens 6 intended to shape a light beam produced by the at least one light source, and a heat sink 7 intended to dissipate heat produced by the light module, and in particular the heat produced by the at least one light source 5A, 5B when the latter is switched on.

[0035] In addition, the light module 1 also comprises a secondary lens 8, positioned downstream of the primary lens 6 in the direction of propagation of the light rays. The secondary lens 8 is arranged at the front opening of the housing 2, at the front of the light module 1. The secondary lens 8 covers the primary lens 6. The secondary lens 8 may be intended to carry out a second shaping of the light beam coming from the primary lens 6. The secondary lens 8 may be fixed to the housing 2, in particular clipped against the housing 2. The secondary lens 8 may comprise an exit diopter of generally spherical shape, possibly provided with a surface structuring.

[0036] In Figures 3 and 4, the light module 1 is shown without the housing 2 and without the secondary lens 8, so as to clearly visualize the at least one printed circuit board 4A, 4B, the primary lens 6, and the heat sink 7.

[0037] As can also be seen in the, the at least one printed circuit board comprises a first printed circuit board 4A and a second printed circuit board 4B separate from the first printed circuit board 4A. The two printed circuit boards 4A, 4B extend parallel to the Y and Z axes and are offset from each other along the X axis. The first printed circuit board 4A is positioned below the second printed circuit board 4B and further back compared to the second printed circuit board 4B. At least one first light source 5A is attached to the first printed circuit board 4A and at least one second light source 5B is attached to the second printed circuit board 4B.

[0038] The printed circuit boards 4A, 4B, commonly referred to as PCBs, comprise conductive electrical tracks and electrical or electronic components configured to supply the light sources 5A, 5B with electrical energy. The printed circuit boards 4A, 4B each further comprise an electrical connector 9A, 9B intended to be connected to an electronic control unit. The switching on of each light source can be controlled individually by the electronic control unit. Each light source 5A and / or 5B can be intended to illuminate a distinct portion of the space. The selective switching on of each light source thus makes it possible to compose light beams of various shapes, and thus makes it possible to perform various lighting functions.

[0039] The light sources 5A, 5B may each comprise at least one light-emitting diode. Alternatively, other types of light sources could be envisaged. In this case, the at least one first light source 5A comprises six light-emitting diodes distributed along a first axis parallel to the Y axis and spaced apart from each other. The at least one second light source 5B comprises a set of light sources placed side by side along a second axis parallel to the Y axis. Alternatively, the number and / or arrangement of the first or second light sources 5A, 5B could be different.

[0040] Referring to Figures 5 and 6, the heat sink 7 comprises a heat sink plate 10 in contact with each of the two printed circuit boards 4A, 4B. The heat sink plate is in contact with a rear face of each printed circuit board 4A, 4B while the light sources 5A, 5B are arranged on front faces of these same printed circuit boards 4A, 4B. A heat conductive paste may be extended between each printed circuit board 4A, 4B and the heat sink plate 10 to ensure good heat conduction. The heat sink plate 10 is made of a material capable of efficiently conducting heat, in particular metal. The heat sink plate 10 may be made of a metal sheet cut and folded into a suitable shape. In particular, the dissipating plate 10 comprises two folds substantially at 90° separating two vertical surfaces against which the printed circuit boards 4A, 4B rest.The heat sink 7 also comprises a set of cooling fins 11 fixed on a rear face of the heat sink plate 10, to increase the heat exchange surface between the heat sink 7 and the ambient air. The cooling fins 11 may be made of metal. They may in particular be made of sheets folded into a "U" shape.

[0041] The primary lens 6 is notably illustrated in FIGS. 7 and 8. The primary lens 6 is configured to shape the light beam produced by the light sources 5A and 5B. In particular, the primary lens 6 is on the one hand configured to shape the light beam produced by the at least one first light source 5A to produce a first light function, notably a light function of the dipped beam type. On the other hand, the primary lens 6 is configured to shape a light beam produced by the at least one second light source 5B to produce a second light function, notably a light function of the high beam type.

[0042] Advantageously, the at least one second light source 5B and the primary lens 6B are configured to provide a light beam complementary to the light beam from the at least one first light source 5A to perform the main beam type light function. Thus, the main beam type light beam is obtained by the simultaneous switching on of the light sources 5A and 5B.

[0043] The primary lens 6 is a monolithic element, i.e. made of a single piece. The primary lens 6 is made of transparent plastic and is obtained by molding.

[0044] The primary lens 6 comprises at least one first input diopter 12A intended to receive light rays produced by the at least one first light source 5A, and at least one second input diopter 12B, distinct from the at least one first input diopter 12A and intended to receive light rays produced by the at least one second light source 5B. The input diopters 12A and 12B are distinct and positioned respectively opposite the light sources 5A and 5B. In this case, the primary lens 6 comprises six first input diopters 12A, each opposite one of the six light sources 5A. Each first input diopter 12A can be positioned at the top of a conical portion of the primary lens 6, in the lower part of the primary lens.The second input diopter 12B can be positioned on a flat face of the primary lens 6 and / or at the interface between two flat surfaces of the primary lens 6, in the upper part of the primary lens.

[0045] At least one input diopter, and in particular the second input diopter 12B, may comprise an edge 13 extending generally parallel to the Y axis, and the shape of which gives the light beam coming from the primary lens a particular shape. In particular, the edge 13 comprises an asymmetrical shape between its right part and its left part, making it possible to produce an asymmetrical light beam, called a "cut-off" light beam, which makes it possible to avoid dazzling motorists traveling in the opposite direction. For lighting devices intended to equip motor vehicles with right-hand drive, the left part of the light beam illuminates less high along the Z axis than the right part of this light beam. The shape of the edge 13 can therefore be adapted to equip motor vehicles with left-hand drive.

[0046] The primary lens 6 also comprises a single exit diopter 14 through which the light rays produced by the light sources 5A and 5B are intended to exit the primary lens. The exit diopter 14 may comprise a spherical or substantially spherical shape. The light rays generated by the at least one first light source are therefore mixed with the light rays generated by the at least one second light source at the exit of the primary lens 6.

[0047] The primary lens 6 further comprises a first reflection surface 15 and a second reflection surface 16. As shown in the with arrows F1, F2 and F3, the light rays from the first light sources 5A enter the primary lens 6 through the first entrance diopter 12A, then are reflected on the first reflection surface 15 and then on the second reflection surface 16 before exiting the primary lens through the exit diopter 14. The first reflection surface 15 is positioned on a face parallel to the Y axis and inclined forward and upward. The first reflection surface 15 deflects the light rays by an angle roughly equal to 90° upward. The first reflection surface 15 may comprise the shape of a Fresnel lens surface, as seen in the. The second reflection surface 16 is positioned at the level of the second entrance diopter 12B, close to the edge 13.The light beam obtained with the first light sources 5A can thus include a cutoff as defined previously.

[0048] Since the light rays undergo reflections inside the primary lens 6, it is understood that the relative positioning between the first light sources 5A and the primary lens 6 must be very precise. Indeed, a small deformation of the primary lens and / or a small offset between the first light sources 5A and the primary lens 6 can, through the play of the different reflections on the reflection surfaces 15 and 16, lead to a significant deformation and / or positioning defect of the light beams at the output of the primary lens 6.

[0049] To prevent any deformation of the primary lens 6, it is held between the housing 2 and the heat sink 7. In other words, the primary lens 6 is sandwiched between the housing 2 and the heat sink 7. This reduces the mechanical stresses exerted against the primary lens 6, which limits or even prevents any deformation of the primary lens 6.

[0050] For this purpose, the light module 1 comprises a set of fixing screws 17 cooperating with the heat sink 7 and the housing 2. The fixing screws 17 tend to tighten the heat sink against the housing. The primary lens 6 interposed between the heat sink 7 and the housing 2 is thus blocked between these two components.

[0051] In this case, the light module comprises three fixing screws 17. However, as a variant this number could be different, for example, two, four or five fixing screws 17. The fixing screws 17 cooperate with fixing wells 18 formed in the housing 2. The fixing wells 18 are blind holes, preferably pre-threaded. Each fixing screw 17 extends parallel to the X axis and passes through an opening 19 provided in the heat sink plate 10 for this purpose. Each fixing screw 17 comprises a screw head bearing against the rear face of the heat sink plate 10 and a threaded portion screwed into a fixing well 18.

[0052] As also shown in the, the primary lens 6 comprises openings 20 through which the fixing screws 17 pass. The openings 20 are large enough so that the fixing screws are not in contact with the primary lens 6. In particular, the threaded portion of the fixing screws 17 passes through each opening 20 but does not touch the edges of these openings. The openings 20 are unthreaded. The fixing screws 17 thus do not generate any additional mechanical stress on the primary lens 6. According to the embodiment shown, the openings 20 have a closed contour. Alternatively, the openings 20 could also have an open contour, as is for example the case of the opening 20' visible in the.

[0053] The two printed circuit boards 4A and 4B are also held between the housing 2 and the heat sink 7. A first face of each printed circuit board 4A, 4B bears directly against the primary lens 6. A second face of each printed circuit board 4A, 4B bears directly against the heat sink 7. More precisely, a front face of each printed circuit board 4A, 4B bears directly against a rear face of the primary lens 6. A rear face of each printed circuit board 4A, 4B bears directly against a front face of the heat sink plate 10. It is therefore understood that the primary lens 6 bears against the heat sink 7 via the printed circuit boards 4A, 4B on the one hand, and on the other hand that the printed circuit boards 4A, 4B bear against the housing 2 via the primary lens 6.The primary lens 6 can therefore be without direct contact with the heat sink 7 and the printed circuit boards 4A, 4B can be without direct contact with the housing 2.

[0054] With reference to the, the primary lens 6 comprises a set of bearing surfaces 21 by means of which it bears on the printed circuit boards 4A and 4B. The bearing surfaces 21 extend parallel to the Y and Z axes. The bearing surfaces are provided around the openings 20 and at the end of pads provided for this purpose. The bearing of the printed circuit boards against the bearing surfaces 21 makes it possible to precisely define the relative position between the primary lens 6 and the light sources 5A and 5B along the X axis.

[0055] As can also be seen in the, the printed circuit boards 4A and 4B each comprise openings 22 through which the fixing screws 17 pass. The openings 22 are sufficiently large so that the fixing screws 17 are without contact with the printed circuit boards 4A, 4B. In particular, the threaded portion of the fixing screws 17 passes through each opening 22 but does not touch the edges of these openings. The openings 22 are unthreaded. The fixing screws 17 thus do not generate any additional mechanical stress on the printed circuit boards 4A, 4B.

[0056] The primary lens 6 further comprises at least two first centering elements 23A cooperating with the first printed circuit board 4A to position the primary lens 6 relative to the first printed circuit board. Similarly, the primary lens 6 comprises at least two first centering elements 23B cooperating with the second printed circuit board 4B to position the primary lens relative to the second printed circuit board. The first centering elements 23A, 23B may take the form of pins of generally cylindrical or frustoconical shape, and extending parallel to the X axis towards the rear. The first centering elements 23A, 23B cooperate with openings 24A, 24B provided respectively in the printed circuit boards 4A, 4B for this purpose.The cooperation of the first centering elements 23A, 23B with the openings 24A, 24B makes it possible to precisely position the printed circuit boards 4A, 4B (and therefore the light sources 5A, 5B fixed to the printed circuit boards) relative to the primary lens 6 along the Y and Z axes, which makes it possible to achieve significant precision and optical performance. The centering elements 23A and 23B therefore pass through the printed circuit boards 4A and 4B. The use of two centering elements for each printed circuit board 4A, 4B makes it possible to avoid rotation of the printed circuit board around a centering element. Alternatively, a number of centering elements greater than or equal to three could be envisaged.

[0057] The distal end of the first centering elements 23A, 23B protrudes from the rear face of the printed circuit boards 4A and 4B. In order to avoid contact between the first centering elements 23A, 24B and the heat sink 7, the latter comprises holes 31 through which the centering elements 23A and 23B pass. The first centering elements 23A, 24B nevertheless remain without contact with the edges of the holes 31.

[0058] Advantageously, and as can be seen in the, the heat sink 7 comprises two second centering elements 25A cooperating with the first printed circuit board 4A to position the heat sink relative to the first printed circuit board. Similarly, the heat sink 7 comprises three second centering elements 25B cooperating with the second printed circuit board 4B to position the heat sink relative to the second printed circuit board. The second centering elements 25A, 25B may take the form of pins of generally cylindrical or frustoconical shape, and extending parallel to the X axis forward from the heat sink plate 10. The second centering elements 25A, 25B cooperate with openings 26A, 26B provided respectively in the printed circuit boards 4A, 4B for this purpose.The cooperation of the second centering elements 25A, 25B with the openings 26A, 26B makes it possible to precisely position the printed circuit boards 4A, 4B (and therefore the light sources 5A, 5B fixed to the printed circuit boards) relative to the heat sink along the Y and Z axes, which makes it possible to achieve efficient cooling of the light sources 5A, 5B.

[0059] Finally, the housing 2 comprises three third centering elements 27 cooperating with the primary lens 6 to position the primary lens relative to the housing, and in particular to position the primary lens 6 relative to the secondary lens 8 and relative to the vehicle, since the secondary lens 8 is fixed to the housing and the housing itself is fixed to the vehicle. The third centering elements 27 may take the form of pins of generally cylindrical or frustoconical shape, and extend parallel to the X axis towards the rear. The third centering elements 27 cooperate with openings 28 provided in the primary lens 6 for this purpose. The openings 28 have an elongated oval shape parallel to the Y axis or parallel to the Z axis. The cooperation of the third centering elements 27 with the openings 28 makes it possible to precisely position the primary lens 6 relative to the housing 2 along the Y and Z axes.The third centering elements 27 further pass through holes 29 provided in the first printed circuit board 4A and through holes 30 provided in the heat sink 7, in particular in the heat sink plate 10. The third centering elements 27 nevertheless remain without contact with the edges of the holes 29 and without contact with the edges of the holes 30.

[0060] To assemble the light module as described above, the following procedure can be used. First, the housing 2, the primary lens 6, the secondary lens 8, the printed circuit boards 4A, 4B equipped with their respective light sources 5A, 5B, the heat sink 7, and the fixing screws 17 are provided. Next, the primary lens 6 is inserted into the housing through the rear opening of the housing. The correct positioning along the Y and Z axes of the primary lens 6 relative to the housing 2 is obtained by cooperation of the third centering elements 27 with the openings 28. Next, the printed circuit boards 4A and 4B are inserted into the housing 2 through the rear opening of the housing. The correct positioning along the Y and Z axes of the printed circuit boards 4A and 4B relative to the primary lens 6 is obtained by cooperation of the first centering elements 23A, 23B with the openings 24A, 24B.Next, the heat sink 7 is inserted into the housing 2 through the rear opening of the housing. The correct positioning along the Y and Z axes of the heat sink 7 relative to the printed circuit boards 4A and 4B is obtained by cooperation of the second centering elements 25A, 25B with the openings 26A, 26B. Finally, the fixing screws 17 are screwed into the fixing wells 18 of the housing 2 to press the primary lens 6 against the housing 2, the printed circuit boards 4A and 4B against the primary lens 6, and the heat sink 7 against the printed circuit boards 4A and 4B. This provides a correct positioning of these components along the X axis. Finally, the secondary lens 8 can be fixed to the housing 2, in particular clipped to the housing 2, at its front opening.

[0061] The result is a light module 1 that is easy to manufacture and whose components are well positioned relative to each other in all three spatial directions. The primary lens 6 does not bear any unnecessary stress related to its attachment, which prevents any deformation of the latter. This achieves optimal optical precision.

Claims

Light module (1) for a motor vehicle, characterized in that it comprises:- a housing (2),- at least one printed circuit board (4A, 4B) on which at least one light source (5A, 5B) is fixed,- a primary lens (6) intended to shape a light beam produced by the at least one light source, and- a heat sink (7) intended to dissipate heat produced by the light module, the primary lens being held between the housing and the heat sink. Light module (1) according to the preceding claim, characterized in that the heat sink (7) is fixed to the housing (2) by a set of fixing screws (17), and in that the primary lens comprises a set of openings (20), at least one fixing screw passing through at least one opening of the primary lens. Light module (1) according to the preceding claim, characterized in that said fixing screws (17) are without contact with the primary lens (6). Light module (1) according to one of the preceding claims, characterized in that the at least one printed circuit board (4A, 4B) is held between the housing (2) and the heat sink (7), one face of the at least one printed circuit board being in direct contact with the primary lens (6). Light module (1) according to one of the preceding claims, characterized in that the primary lens (6) comprises at least two first centering elements (23A, 23B) cooperating with the at least one printed circuit board (4A, 4B) to position the primary lens relative to the at least one printed circuit board. Light module (1) according to one of the preceding claims, characterized in that the heat sink (7) comprises at least two second centering elements (25A, 25B) cooperating with the at least one printed circuit board (4A, 4B) to position the heat sink relative to the at least one printed circuit board. Light module (1) according to one of the preceding claims, characterized in that the primary lens (6) is a monolithic element made of transparent plastic, and in that it is obtained by molding. Light module (1) according to one of the preceding claims, characterized in that the at least one light source (5A, 5B) comprises at least one first light source (5A) and at least one second light source (5B), the primary lens (6) being configured to shape a light beam produced by the at least one first light source to produce a first light function, in particular a light function of the dipped beam type, the primary lens (6) being configured to shape a light beam produced by the at least one second light source to produce a second light function, in particular a light function of the main beam type. Light module (1) according to the preceding claim, characterized in that the primary lens comprises at least one first input diopter (12A) intended to receive light rays produced by the at least one first light source (5A), at least one second input diopter (12B), distinct from the at least one first input diopter and intended to receive light rays produced by the at least one second light source (5B), and a single output diopter (14) through which the light rays produced by the at least one first light source and by the at least one second light source are intended to emerge from the primary lens. Light module (1) according to one of the preceding claims, characterized in that the primary lens comprises a first reflection surface (15) and a second reflection surface (16), at least part of the light rays produced by the at least one light source (5A) being intended to be reflected on the first reflection surface then on the second reflection surface before exiting the primary lens.

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