The present invention refers to a method for producing a molded cap and to a molded cap.

BACKGROUND

Molded caps and particular molded caps with a transparent window are often used as receptacles for optoelectronic components. In some applications involving laser elements as optoelectronic components, such transparent windows are not only used for light forming, but also for security purposes, namely to prevent in juries in case a user looks directly into the laser light. Hence, such transparent window, or generally the transparent element or more particular the transparent lens must not only be placed securely within the cap. It has also to be ensured that not damage occurs during manufacturing and later use. For example, the lens should be rigidly fixed and not drop or crack during manufacture or later use. To detect such occurrences, usually electronic measures are taken. However, the usual man ufacturing processes either lead to issues with the transparent window being polluted or still include the above-mentioned risks.

In summary, the desire remains to obtain a more efficient man ufacturing method for producing those caps.

SUMMARY OF THE INVENTION

The inventors realized that one main issues lies in the handling of glue, as it not only may pollute portion of the transparent window to be kept clean, the glue may also lose its adhesion resulting in either cracks or partial drop of the transparent window. This issue may increase due to temperature differences, resulting in different stress on the respective elements. The inventors therefore propose a different manufacturing method, in which a transparent element is embedded within the mold material, thus keeping the transparent element in proper position, while at the same time reducing the likelihood of damages or cracks in the transparent element or preventing it from becoming lose.

In some aspects, a method of manufacturing a molded cap is proposed, wherein the molded cap comprises a transparent element and a receptacle for an optoelectronic component. In a first step, a mold bottom base having a protruding pillar with a depositing area is provided. A transparent element is arranged onto the depositing area of the protruding pillar, such that a surrounding edge portion of the transparent element extends beyond the depositing area. A mold top base having a protruding circumferential strip with a sealing surface is then provided. The sealing surface is placed onto the transparent element such the surrounding edge portion of the transparent element remains uncovered by the sealing surface. Finally, a mold component is filled into a space between the surrounding edge portion and the protruding pillar and between the surrounding edge portion and the protruding circumferential strip. The filling of the mold material will encapsulate the surrounding edge portion from both sides and hold them rigidly tight, thereby forming the molded cap. The proposed method encapsulates the cap completely from both sides. Contrary to conventional method, wherein the transparent element is placed on a previously molded cap, the present dis closure proposes to process the transparent element when forming the cap. This enables a direct connection between the molded material and the transparent element without additional use of a glue.

Some aspects relates to the processing and preparation of the transparent element. In a first step, the transparent element is produced and provided for further processing. The production of the element is done independent from the further processing of the transparent element. The transparent element is gripped and positioned over the protruding pillar. For this purpose, there are various possibilities to grip the transparent element. In some aspects, the transparent element is gripped on the edge portion. Alternatively, the transparent element can be sucked on a surface portion, which is subsequently facing the top mold base. After orienting the gripped element properly, it can be released onto the protruding pillar. Such approach also enables re-positioning the transparent element in case it has wrongly or not properly positioned.

In some further aspects, the transparent element is sucked onto a surface of the protruding pillar. The protruding pillar may include one or more suction holes to suck the transparent ele- ment onto the surface. This will place the transparent element firmly onto the pillar, which is suitable when mold material is later filling the space. Of course in some aspects more than one pillar can be arranged on which subsequently a plurality of lenses or other transparent elements can be placed upon.

The mold material will encapsulate the edge portions of the transparent element. In some aspects, a size of a surface facing the mold top base of the surrounding edge portion encapsulated in mold component is substantially equal to a size of a surface facing the mold bottom base of the surrounding edge portion encapsulated in mold component. In some other aspects, the size of the respective are different. Encapsulating the transparent element with different sizes can be beneficial depending on the application.

Some other aspects related to the structure of the mold tool. In some aspects, the circumferential side surfaces of the pro truding pillar is inclined towards a virtual center of the pillar. Likewise, side surfaces of the circumferential protrud- ing strip facing outwards can be inclined towards a virtual center of the circumferential protruding strip. The inclination enables the mold tool to be easier separated and reduce the risk that mold material gets stuck or is ripped apart thereby reduc ing the grip on the transparent element. In some aspects, the transparent element is a transparent window. However, the trans- parent element may also comprise a light forming element like a lens or a filter. Generally speaking, the transparent element can include one or more light-forming, light-directing or light filtering functionality. In some aspects, the transparent ele ment can form a dome shape or include a grooved lense and the like

The transparent element may comprise a rectangle or a square, also ellipsoid and other forms may also be possible. The sur rounding portion may follow with its shape the area, which is used for the light, although it may vary therefrom. For example, portions of the transparent element that are intended for light to feed through may comprise a shape that is different from the surrounding edge. This will enable encapsulating the surround ing edge portion in the desired manner improving stability and reducing the risk for cracks or unintended drops.

During the molding process and the pressure exerted, some mold material can spoil under the sealing surface of the mold top base. To prevent this material from leaking through the space between the sealing surface and the transparent element, it is proposed in some aspects to provide a width of the protruding circumferential strip 2b at least equal compared to a width of the surrounding edge remaining uncovered by the sealing surface. Thus, the width of the protruding circumferential strip is ad- justed such that the pressure exerted by the sealing surface onto the transparent element is large enough to prevent leakage. In some aspects, the pressure exerted by the sealing surface onto the transparent element is at least equal to the pressure exerted by the mold material or to the pressure of the mold when filling the space inside the mold tool Some aspects are related to a mold cap. The mold cap comprises a cavity adapted to receive an optoelectronic component. The cavity also comprises a top surface including an opening therein. In a fully assembled stage, the top surface will cover the optoelectronic component placed inside the cavity. The top surface comprises a non-transparent mold material. A transpar ent element is arranged inside the opening. The transparent element comprises a surrounding edge portion that is encapsu lated within the non-transparent mold material, thus securing the transparent element tightly with the mold material and the molded cap. In addition, a top surface of the transparent ele ment is recessed with regard to an edge of the opening.

The transparent element may include a light forming element, a lens, a filter or any other light directing element. Further examples for such transparent element are provided in this dis closure. The surrounding edge portions may include different forms to ensure proper grip and encapsulation. In some aspects, the surrounding edge portion of the transparent element comprise the shape of a rectangle and in particular a square. In some further aspects, the side edged of the opening, in which the transparent element is embedded is inclined. The edges are in clined in direction to the transparent element towards a center of the opening when viewed in a cut view.

SHORT DESCRITPITON OF THE DRAWINGS

Further aspects and embodiments in accordance with the proposed principle will become apparent in relation to the various em bodiments and examples described in detail in connection with the accompanying drawings in which

Figure 1 shows a perspective view of a molded cap in accordance with some aspects of the present disclosure; Figure 2 illustrates a side view of a preparatory step in a molding tool to illustrate some relevant aspects of the present disclosure; Figure 3 shows a top view on a portion of a molded cap to further illustrate some aspects of the present disclosure;

Figure 4 shows various method steps of a method for producing a molded cap in accordance with some aspects of the present invention.

DETAILED DESCRIPTION

The following embodiments and examples disclose different as pects and their combinations according to the proposed princi- pie. The embodiments and examples are not always to scale. Likewise, different elements can be displayed enlarged or re duced in size to emphasize individual aspects. It goes without saying that the individual aspects of the embodiments and ex amples shown in the figures can be combined with each other without further ado, without this contradicting the principle according to the invention. Some aspects show a regular struc ture or form. It should be noted that in practice slight dif ferences and deviations from the ideal form may occur without, however, contradicting the inventive idea.

In addition, the individual figures and aspects are not neces sarily shown in the correct size, nor do the proportions between individual elements have to be essentially correct. Some aspects are highlighted by showing them enlarged. However, terms such as "above", "above" "below", "below" "larger", "smaller" and the like are correctly represented with regard to the elements in the figures. Therefore, it is possible to deduce such rela tions between the elements based on the figures. Figure 1 illustrates an embodiment of the molded cap 1 in ac cordance with several aspects of the present disclosure. The molded cap 1 includes a cavity 12, which is formed as a recep tacle for an optoelectronic component to be placed within cavity 12. An opening 11 is arranged on the cover of cavity 12 (which in view of figure 1 is the top of cavity 12), in which a transparent element 2 in form of a lens is embedded into.

For the purpose of simplification, the transparent element 2 may be referred to herein as lens 2. However, it is understood, that transparent element 2 can form any kind of light-directing, light-forming and light-filtering element. To this extent, lens 2 as the transparent element is therefore considered as a non limiting example. Lens 2 comprises a rectangular shape and is arranged substantial centrally over opening 11. Opening 11 and lens 2 together form a recess with side surfaces 13, the side surfaces 13 being part of the cover of molded cap 1. In this example side surface 13 is inclined towards the center of open ing 11, when looked from the top view onto cap 1.

In accordance with the present disclosure, lens 2 is embedded within the mold material of cap 1. Hence, certain areas of lens 2, further referred to as edge portion of lens 2 or edge portions of transparent element 2, are encapsulated by the mold material from both sides. As a result, lens 2 is tightly fixated within the mold material and thus forms an integrated part of the molded cap 1.

Figure 2 shows a cut view of the molding tool, including the transparent element or lens 2 ready to be embedded within mold material during manufacture of the molded cap. Figure 2 shows a step within the method for producing a molded cap in accord ance with some aspects of the present disclosure.

The molding tool comprises a mold bottom base 20 and a mold top base 21. The mold bottom base 20 includes a flat portion as well as a protruding pillar 24.A depositing flat area 23 is arranged on its top surface. Throughout the depositing flat area 23, a plurality of suction holes 22 are included within pillar 24. The suction holes create a pressure difference towards the transparent element 2 being placed on the depositing carrier, thus sucking the transparent element towards the depositing area and holding it tight.The protruding pillar 24 further comprises an inclined side edge 25, wherein the inclination is directed towards the center of the pillar when viewed in a cut view from the bottom part towards the depositing area 23. The inclined side edge 25 of pillar 22 will enable an easier separation of the mold bottom base 20 after the mold material is filled in within the space 31 and 30 and subsequently cooled down.

Mold top base 21 includes a circumferential strip 26 encompass ing an empty space 27 in between. The circumferential strip 26 generally follows the shape of the transparent element and sur rounds a transmission portion 2c on the top lens surface 2b.

The circumferential strip 26 includes, -similar to pillar struc ture 24 of mold bottom base 20-, an inclined outer edge surface 29. The inclined outer edge surface 29 is facing the space 30 between the lens surface 2b and the mold top base 21. Similar to the inclined surface 25, the inclination of inclined edge surface 29 is directed towards the virtual center of the cir cumferential strip 26. After the molding is complete, the mold bottom base as well as the mold top base can be easily separated due to the respective inclined surfaces.

Circumferential strip 26 comprises a sealing surface 26a facing the top lens surface 2b. Said sealing surface 26a comprises a clamping boundary 32, said clamping boundary formed by the edge of the inclined surface 29 being in contact with top lens sur face 2b. As illustrated in Figure 2, the transparent element or lens 2 comprises a surrounding edge portion 40 extending beyond the pillar structure 24 or the circumferential strip 26. In other words, a portion of the top lens surface 2b and the bottom lens surface 2a extends beyond the sealing surface 26a and the depositing area 23, respectively. As a result, a space 31 is formed between the mold bottom base 20 and the surrounding edge portion 40 extending beyond the protruding pillar 24. Like wise, a small space 30 is formed between the surrounding edge portion 40 and the mold top base structure 21.

In accordance with aspects of the present disclosure and for molding the cap 1 as illustrated in figure 1, the mold bottom base portion 20 is provided. In a subsequent step, the trans parent element 2 is positioned over and then placed on the depositing area 23. For holding the transparent element 2 in place and clamping it onto the depositing area 23 of pillar 24, the suction holes 22 are sucked out. This will create a negative pressure holding transparent element to place.

In a next step, mold top base 22 is positioned above the trans parent element 2 and lowered onto element 2 until sealing sur- face 26a of the circumferential strip 26 touches of the top lens surface 2b.

Further, a pressure is exerted by mold top base 21 onto the lens via the sealing surface 26a to isolate space 27 within the circumferential strip 26 from outer space 30. This is necessary, as the mold material is being pressed with relatively high pressure into the space and towards the sealing surface and the circumferential strip.To prevent the mold material from leaking through the circumferential strip and flowing between the top lens surface 2b and the sealing surface 26a, mold top base 21 exerts the pressure onto the transparent element. As a result, when the mold material is pressed into the space 30 and 31, only a small so-called flash area 28 adjacent to the clamping bound ary 33 may be partially covered by residuals of the mold mate- rial. The dimension covered by the sealing surface in relation to other areas of the transparent element 2 is illustrated in Figure 3, showing a top view onto transparent element 2 and mold bottom base 20. Transparent element 2 comprises an outer edge portion 40 of a rectangular shape and surrounding the transmis sion portion 2c. Between transmission portion 2c and outer edge portion 40, circumferential area 2d including portion 28 and 2e is arranged. Areas 28 and 2e are covered by the sealing surface 26a of the mold top base 21. The clamping boundary 33 indicates the outer edge of the sealing surface 26a.

When exerting pressure and subsequently filling a mold material into space as outlined with regard to Figure 2, portions of the mold material can be pressed between the sealing surface 26a and the top surface of lens. Therefore, the lateral dimensions of the sealing surface 26a and the pressure exerted during the mold process is chosen to ensure a tight seal between the outer space 30 and the inner space 27.it is noted that a larger pressure can result in a smaller sealing surface and vice versa. However, the pressure shall not be too high to avoid cracking or damaging the transparent element. Hence, it may be suitable to increase the sealing surface 26a, covering a larger area on the top lens surface. Hence, a sacrificial area 28 referred to as flash area 28 is provided on the sealing surface 26, in which portions of the mold material can flow or be pressed into. Mold material will form residuals on this area of the top lens surface. Neverthe less, the lateral dimension of the sealing surface 26a is large enough that no further mold material is pushed onto area 2e adjacent to the transmission portion 2c. In other words, while the flash area 28 may still comprise residual mold material, area 2e is supposed to be clean and free of any mold material. The covered lens surface 2d shall be selected such that mold material cannot be pressed inside space 27 and onto transmission portion 2c. Figure 4 illustrates the 5 main steps of the proposed method for producing a molded cap. In accordance with several aspects of the present disclosure, a molded cap comprises a transparent element and a receptacle or cavity for an optoelectronic com- ponent. A mold bottom base having a protruding pillar with depositing area is provided in step SI. The protruding pillar may include a plurality of suction holes to create a negative pressure, holding a transparent element to be arranged upon the protruding pillar in place.

In a subsequent step S2, a transparent element 2 is positioned and arranged on the depositing area 23 of the protruding pillar 24. The position is adjusted such that surrounding edge portion 40 of the transparent element 2 extends beyond the depositing area 23 of the protruding pillar 24. Hence, the transparent element 2 is larger than the depositing area 23 of the protrud ing pillar. In some aspects, the transparent element 2 is cen tered such that it virtual center lies directly above the vir tual center of the protruding pillar 24.

In some aspects of this particular step, the transparent element 2 is previously manufactured in one or several steps. It may be gripped, particularly along its edge portion or on its surface subsequently facing the top mold base. In the latter case, the transparent element may be sucked onto a gripper for a subse quent transfer. The so gripped or clamped transparent element is oriented over the protruding pillar and then released on the depositing area of the protruding pillar. In a next step, the transparent element may be sucked onto the depositing area hold- ing the transparent element in place.

In a next step S3, a mold top base 21 is provided having a protruding circumferential strip 26 with the sealing surface 26a. The circumferential strip 26 circumferences an area, which corresponds to or at least later encloses the transmission por tion of the transparent element. In step S4, the sealing surface 26a is placed onto the trans parent element such that surrounding edge portion of the trans parent element remains uncovered by the sealing surface. As a result, the surrounding edge portion of the transparent element protrude from the mold top base and mold bottom base into the empty space provided by the arrangement of the mold top base 21 and the mold bottom base facing each other.

After correct positioning of the mold top base, the mold top base will exert a certain pressure on to the sealing surface thereby tightly sealing the surface of the transparent element and separating the space within the circumferential strip from the outer space. This will ensure that the mold material being filled in a subsequent step within the space formed by the mold top base and the mold bottom base does not flow into the space created by the circumferential strip and onto the transmission portion of the transparent element.

Finally, a mold component is filled into the space between the surrounding edge portion and the protruding pillar and between the surrounding edge portion and the protruding circumferential strip. As a result, the mold material encapsulates the sur rounding edge portion of the transparent element, embedding the transparent element partially within the mold material. After cooling the mold material, the mold top base can be separated from the newly molded cap the mold top base is lifted away from the mold bottom base.

The present method disclosed herein is focused on the manufac- turing of a single molded cap. However, the method is not re stricted or limited to such individual mold process. Rather, the proposed method can be multiplied such that a mass transfer of transparent elements onto a plurality of pillars can be performed.A mold top base having a plurality of circumferential strips each with a sealing surface as disclosed herein can then be placed over the plurality of lenses resting on the respective depositing areas.

The method will therefore allow for a mass production, wherein the transparent elements in form of lenses or other light directing, light-forming or light-filtering elements are embed ded in the mold material of the molded cap. After producing a plurality of molded caps in accordance with the proposed prin ciple, these caps can be separated by mechanical means if nec- essary.

The transparent element being embedded within the mold material of the molded cap ensures a tight and safe arrangement with improved tolerances in comparison to conventional lens attach process. The risk for lens dropping is virtually avoided since the lens is now embedded within the mold material. The previ ously necessary attachment process, including gluing the lens onto the material is avoided, thereby eliminating potential issues with lens cracking during the gluing process. As a re- suit, safety for a user is improved and the subsequent pro cessing simplified.

REFERENCE LIST

1 molded cap

2 transparent element, lens 2a bottom lens surface 2b top lens surface 2c transmission portion 2d covered lens surface 2e area 11 cap opening 12 cap cavity 13 side edges 20 mold bottom base 21 mold top base 22 suction holes

23 depositing area

24 pillar

25 inclined side edge

26 strip 26a sealing surface

27 space

28 flash area 29 inclined strip surface

30, 31 mold space 33 clamping boundary

40 surrounding edge portions