DE102005051807A1 - Circuit board e.g. for SMD components, has unit provided with retention zone comprising neck and thickening connected to neck - Google Patents

Abstract

A circuit board is equipped with electrical components and at least one unit, in which the respective unit has a retention zone which comprises a neck and a thickening connected to the neck, and in which the thickening is retained in the region of a plated through metallised aperture of the circuit board and held by solder material. Independent claims are included for the following. (A) A light-guide; and (B) A light-guide arrangement.

Description

The The invention relates to a printed circuit board, a light guide and a Optical fiber arrangement.

At the Manufacture of electronically populated printed circuit boards are SMD placement machines known, the electrical components, such as capacitors, resistors, integrated circuits, remove a memory and onto the circuit board position. The previously applied adhesive solder paste holds the components while the subsequent passage through a furnace. It stores and connects to be soldered to metallic surface areas, like metallic traces on the circuit board and metallic ones Feet of the Components. The resulting solder joint exercises so mechanical holding forces between the metallic areas of both parts, ie component and circuit board, off. About that It goes without saying causes an electrical contact. The memories often exist from long ribbons, in which similar components are arranged one behind the other. When loading Then the tape is successively emptied and the removed component fitted on the circuit board.

From the US Pat. No. 6,159,045 is an electrical component, that is, an electrical component, known, which in addition to the metallic solder joints also receives an increase in the holding force for the component from a thickened area stuck in a via, as in 5 is shown.

It Light guides are known, although by hand with a printed circuit board or a housing get connected.

Of the The invention is therefore based on the object to develop a printed circuit board, as possible little manual loading necessary is.

According to the invention Task with the circuit board according to claim 1, in the light guide according to claim 10 and in the light guide assembly according to the solved in claim 14 specified characteristics.

Important features of the invention in the printed circuit board are that it is fitted with electrical components and at least one component,
wherein the respective component has at least one holding region, which comprises a constriction and an adjoining thickening,
wherein the thickening is provided in the region of a via of the printed circuit board and is held by solder.

From The advantage here is that an otherwise handzubestückendes part now from the placement machine Equipped in a similar way is as well as electrical components. These are in the Component not an electrical component but a different kind. It has no electrical contacts or metallic contact areas. Especially is a component of a light guide made of special plastic used, has the appropriate properties.

at an advantageous embodiment is the item to be soldered with metallized areas connected to the via, in particular cohesively. Advantageous is there that a mechanically stable connection of the soldering provided is.

at According to an advantageous embodiment, the component is a light guide. The advantage here is that the light guide through the furnace together can be moved with the other electrical components and the previously applied solder paste holding him mechanically. Thus, he does not have to be populated by hand and he can an electrical component can be equipped by the machine.

at an advantageous embodiment, the component is made of a plastic, on the one hand has such low absorption of light that the Component is used as a light guide, and on the other hand a such low surface tension to the item to be soldered that wetting of essential parts of the holding area accomplished is, in particular without significant air or inert gas inclusions. From The advantage here is that without the inclusions and with good wetting a mechanically stable connection can be realized. Besides that is it surprisingly that a plastic is used, which despite the exposure At the high furnace temperatures light is absorbed only slightly, leaving the light guide receives its function of transmission of light. The temperatures can go up 240 ° C or even 260 ° C.

at An advantageous embodiment is at the light guide at least a lens for radiating the irradiated in the light guide Light formed. The advantage here is that the lens can be used as a diffuser is. This is the surface the lens in addition roughened executable.

In an advantageous embodiment, a light-emitting means is provided between the printed circuit board and the light guide, in particular SMD-mountable LED, wherein contacts of the light-emitting means with electrical conductor tracks of the printed circuit board are in electrical connection. In particular, the optical fiber exercises housing forming property, in particular therefore mechanical protective function, for the light source from, in particular at least partially surrounds the light source. The advantage here is that the light source can be fitted on the circuit board and then the light guide can be placed over it on the circuit board, so can be fitted. Thus, the light emerging from the light source is easily trappable by the light guide.

Especially the light guide is designed according to its mechanical form as well as with a light-attenuating Color processed on one side to an unwanted coupling of the light on Directly placed next to prevent light guide. This is a juxtaposition of several optical fibers directly next to each other easily possible without a crosstalk of the light from one to the other light guide.

at an advantageous embodiment is the plastic of the type PES or PSU, in particular he therefore the class of polysulfones or polyethersulfones. From The advantage here is that the plastic has the mentioned properties of the surface tension, of absorption and additionally having mechanically sufficient strength.

at an advantageous embodiment of the light guide is together with the components of the soldering process an environment exposed in the oven below 260 ° C, in particular below 240 ° C. Advantageous is that the plastic after soldering, so after driving through of the furnace, having its stated properties.

Important Features of the invention in the light guide are that a first side surface with a light-attenuating Color and / or coating is provided. The advantage here is that Light guide are lined up. The crosstalk is reduced. Because the transgressing Light is attenuated.

at an advantageous embodiment weakens the lichtabschwächenden Color and / or coating passing through the first side surface Turn off the light or weaken it. From The advantage here is that absorbent coatings or colors are usable. Thus, light that emerges is absorbed and can not enter an adjacent optical fiber. Analog becomes from the outside coming light, for example coming from another light guide Light is prevented from entering and therefore can not disturb.

at an advantageous embodiment is the lichtabschwächende color and / or coating an at least partially light-reflecting or light-absorbing coating. The advantage here is that Also, a reflective layer can be applied. This can be through a thin one metallic coating can be produced while maintaining a high Achieve efficiency in the prevention of crosstalk.

at an advantageous embodiment has the opposite second side surface Such a recess that only a part of the first side surface of a another, directly parallel, adjacent light guide touching is. The advantage here is that less area is touching, in particular So a big one Part of the area instead on touch kept at a distance in a simple and cost-effective manner. Thus, the crosstalk further reducible. Preferably, the first side surface is hereby even and the second side surface consists of two parallel subregions, which are arranged offset are. Here then the smaller part is touching the first side surface of the adjacent light guide and the larger portion spaced. Preferably this distance is more than a half or a whole wavelength. ever bigger the The distance the lower the crosstalk. This even decreases exponentially with the distance.

Important Features of the fiber optic array are that two or more above described light conductors side by side on a circuit board are arranged, in particular touching or with a smaller Distance as a quarter of the light to be transmitted. Is an advantage thereby that compact arrangements are made possible, with which the Display means consist of several small areas, one of which Optical fibers are supplied.

Of the Optical fiber passes the light generated by the bulb to the display surface, ie the space area, which should have the luminous surface areas. For this purpose, a ball lens is preferably formed on the light guide, the as uniform a glow as possible Provides in all directions, as it has a smaller diameter has as the light-transmitting portion of the light guide.

Further Advantages emerge from the subclaims.

1

component

2

circuit board

3

via, metallized surface area

4

solder

5

narrowing

6

thickening

20

lens

21

contact areas

22

Lamp

31

optical fiber

32

narrowing

33

thickening

34

Side surface, black printed

35

lens

36

recess

37

sloping surface

The Invention will now be explained in more detail with reference to figures:

In the 1 an arrangement according to the invention is shown symbolically in sectional view.

The printed circuit board has a recess, which has a metallized surface region at its edge region, on which solder is soldered 4 connect with the soldering process. The component 1 is designed with a holding area that has a narrowing 5 and a thickening 6 includes. These two areas are designed such that at least the thickening is provided in the region of the recess of the printed circuit board.

Consequently is the component by means of a machine, for example by means of an SMD placement machine, automatically equippable. The component is, for example, in one of bands Memory can be arranged. So a band contains serially in succession arranged copies of the component.

Especially is advantageous in further embodiments of the invention that the component is not an electrical component but a plastic part, such as optical fibers.

Because the thickening is made of plastic and is surrounded by the item to be soldered in the area of the through-hole. The item to be soldered connects on the one hand with the metallized areas of the via and on the other hand surrounds the item to be soldered the plastic surface the component immediately. The surface tension of the plastic to the item to be soldered is so chosen that the plastic is wetted without significant inert gas or air pockets result.

This is therefore surprising because the plastic as well yet the property has little to absorb light and therefore the Component executable as a light guide is.

at further embodiments of the invention the recess is designed as a bore.

at further embodiments of the invention has the light guide as a component more than just a holding area. It is held by several vias. In particular, will in the intermediate region between the light guide and the printed circuit board provided a light source, which itself is SMD-populated. It therefore has electrical connections on to tracks of the circuit board. The light guide surrounds, so to speak the bulb. Therefore, there is also a mechanical protection from the light guide for the Lamps running.

at In SMD technology, the devices are placed on the solder paste-wetted circuit board stocked, so positioned. Thereafter, the printed circuit board is equipped by a Oven driven. This creates the solder joint between the components and the metallic traces of the circuit board by change the solder paste.

Of the Fiber optic radiates mainly Significant proportions of the light received by the bulb over a lens formed on it in one direction, the axis of which is perpendicular is provided to the normal direction of the circuit board.

at other embodiments of the invention Other directions in which the light is steerable are also advantageous is.

This is in 2 symbolically represented:
The Lens 20 is at the light guide, so the component 1 formed and the bulbs 22 is at the contact areas 21 with conductor tracks of the printed circuit board in soldered connection for mechanical holding and for electrical connection.

at further embodiments of the invention is the plastic of the type PES or PSU, in particular he belongs the class of polysulfones or polyethersulfones. Advantageous is that the plastic the mentioned properties of the surface tension, of absorption and additionally having mechanically sufficient strength. Besides that is the light guide together with the components in the PCB close Areas with solder paste provided and is the soldering process exposed in the oven to an ambient temperature below 260 ° C, especially below 240 ° C. The advantage here is that the plastic after driving through the furnace has the properties mentioned.

In further embodiments of the invention, the plastic is chosen such that, although no wetting occurs, but the solder paste between the via and the constriction 32 Component can pass. The important thing is that after converting and curing the solder paste, a mechanical hold of the component is available. The better the wetting, the more mechanically strong the compound.

In 3 is a light guide 31 shown as an inventive component in an oblique view. In 4 is the same light guide 31 shown in another oblique view. He has two feet, a narrowing 32 and a thickening 33 include. Between the circuit board and the bottom of an LED is provided as a light source on the circuit board, whose light is deflected by the light guide and a substantial proportion of the lens 35 is emitted.

A the side surfaces is dyed black, in particular printed black. In this way it is achieved that unimportant Excess amounts of scattered light or no stray light emerges. Thus, it is possible that several such optical fibers on the circuit board directly next to each other, especially touching, are providable without stray light of an adjacent light guide enters and disturbs. The black color absorbs on the one hand from the light guide leaking and on the other hand light entering from the adjacent light guide. ever thicker the layer of black color the better the absorption pronounced.

For stringing together several optical fibers 30 So it is sufficient that always a side surface is colored. Because this then touches the other side surface of the adjacent light guide and absorbs its exiting stray light.

One so-called crosstalk of light is thus in such a parallel arrangement of at least allows two light guides.

Further improved is the suppression of crosstalk through the recess 36 , This is namely on the opposite side surface of the light guide 30 appropriate. Thus, the contact area is reduced and the crosstalk further reduced. Thus, even if the layer of black coloration is made only thin or small uncolored areas are present for reasons of production, the recess is reduced 36 the crosstalk considerably.

at further embodiments of the invention is also instead of the black color one Mirroring, so for example metallic coating used. However, these are slightly higher Costs to be considered.

at further embodiments of the invention is also instead of the black color one other light-attenuating Paint or coating can be applied.

The inclined surface 37 mainly serves to deflect the light radiated by the illuminant onto the lens 35 out. In this case, an angle of the skew relative to the normal of the printed circuit board between 40 ° and 50 ° is particularly advantageous.

The Normal of the black-colored side surface is perpendicular to the normal of the PCB.

The recess 36 is formed so deep that the distance from the directly adjacent arranged light guide in the non-contact area caused by the recess is greater than 0.1 mm, preferably greater than half or even a whole wavelength of the light emitted by the light source.

Claims (14)

Printed circuit board, on the electrical components and equipped at least one component is wherein the respective component at least one holding area having a constriction and a subsequent thickening includes, wherein the thickening in the region of a via the circuit board is provided and held by solder. Printed circuit board according to at least one of the preceding Claims, characterized in that the item to be soldered with metallized areas connected to the via, in particular cohesively. Printed circuit board according to at least one of the preceding Claims, characterized in that the component is a light guide. Printed circuit board according to at least one of the preceding Claims, characterized in that the component is made of a plastic is that on the one hand has such low absorption of light, that the component is usable as a light guide, and on the other hand such a low surface tension to the item to be soldered that wetting of essential parts of the holding area accomplished is, in particular without significant air or inert gas inclusions. Printed circuit board according to at least one of the preceding Claims, characterized in that at the light guide at least one lens formed to the radiation of the light irradiated in the light guide is. Printed circuit board according to at least one of the preceding claims, characterized in that a light-emitting means, in particular SMD-mountable LED, is provided between the printed circuit board and the light guide, whose contacts are electrically connected to electrical conductor tracks of the printed circuit board stands. Printed circuit board according to at least one of the preceding Claims, characterized in that the light guide housing forming property, in particular So mechanical protection function, for the bulbs exerts, in particular the illuminant at least partially surrounds. Printed circuit board according to at least one of the preceding Claims, characterized in that the plastic of the type PES or PSU is, in particular the class of polysulfones or polyethersulfones belongs. Printed circuit board according to at least one of the preceding Claims, characterized in that the light guide together with the components during the soldering process an environment in the oven of not more than 260 ° C is exposed, in particular below 240 ° C. Optical fiber, characterized in that a first side surface with a light-attenuating Color and / or coating is provided. Optical fiber according to at least one of the preceding Claims, characterized in that the light-attenuating color and / or coating that through the first side surface attenuates passing light or has weakened. Optical fiber according to at least one of the preceding Claims, characterized in that the light-attenuating color and / or coating an at least partially light-reflecting or light-absorbing Coating is. Optical fiber according to at least one of the preceding Claims, characterized in that the opposing second side surface a Such recess has that only a part of the first side surface of a another, directly parallel, adjacent light guide touching is. Optical fiber arrangement, comprising light guides according to at least one of the preceding claims, characterized, that the light guides arranged side by side on a circuit board are, in particular, touching or at a distance less than one quarter of the one to be conducted Light.