DE102007040596A1 - Lamp, for doctors and dentists, has a LED with a heat-conductive filling material and lacquer between the lamp and the base plate and filling the drillings for the electrical connections - Google Patents

Abstract

The lamp has a LED within a housing (GH) with electrical contacts through a base plate (GP). A heat-conductive LED section (HS) has drillings for the electrical contacts followed by a coupling (SO) with passages for the electrical connections. The space between the LED and the heat-conductive section is filled with a heat-conductive material, including the drillings. This increases the contact surface between the heat-conductive section and the LED with heat conduction to the coupling also through the electrical connections. A heat-conductive lacquer (W) is additionally at the edge transit between the mantle of the heat-conductive section of the LED and the base plate and/or LED housing.

Description

The The invention relates to a hand-held device for illuminating a the body to be examined or treated in accordance with the Claim 1.

Medical / dental hand instruments with a lighting device or dental curing device with light have long been known. For example, is from the DE 698 16 716 T2 a dental handpiece with a main part, which contains a turbine head, a coupling and a light source for illuminating the treatment site in the mouth of the patient known. To avoid a halogen lamp with a filament, the light source is a semiconductor device arranged in the turbine head. The optical semiconductor device may be a light emitting diode (LED), in particular a visible light emitting diode (VLED), which has a long life, such as at least 10,000 hours. The VLED is located in the lower distal region of the neck near the head and electrically connected to an external supply source. For this purpose, the VLED is connected to lead wires that pass through the turbine head to contacts at the proximal end of the turbine head. The contacts are in turn connected to contacts in the coupling to provide an electrical connection between the turbine head and the coupling. A projection window aligned with the VLED is provided in the lower distal end region of the neck so that light emitted by the VLED is directed to the tip of the tool to illuminate the treatment site in a patient's oral cavity. Alternatively, the VLED may also be located in the head of the handpiece, in which case the light projection window is aligned with the VLED on the head so that illumination of the treatment site may be effected as described above. Having the illuminator positioned in the head or neck of the handpiece for direct illumination of the treatment site eliminates the need for expensive optical fibers, such as a fiber rod or glass fibers, and minimizes attenuation of the light. Furthermore, the construction of the handpiece is simplified and the cost is reduced.

In further education this is from the EP 1 093 765 A2 a lighting device for a dental or medical instrument, which has a plurality of LEDs and associated holders. The LEDs are arranged so that a lateral lighting without shadows is possible.

A similar lighting device for a medical or dental hand instrument is from the DE 10 2004 006 805 A1 known. In order to display additional information in the field of view of the practitioner, for example to indicate whether caries is present at a site to be treated, means for adding colored light to the illumination cone are provided. The admixture of colored light to the basic lighting is when using sufficiently bright light bulbs clearly perceive for the practitioner and thus allows him to ergonomically provide the additional information.

For example reflect teeth, as well as the adjacent mouth / throat area the incident light and make its color for the practitioner easily recognizable. Preferably, the illumination device is through a white light emitting light source, in particular a white LED is formed. Alternatively, the Means for adding colored light at least one colored light emitting diode, even when using only a single color through a different Intensity of the mixed color different information can be represented. One more way to represent different information or the amount increase the displayable information is to to provide several light-emitting diodes in different colors or it a multicolor LED can be provided, which in one first mode white light to illuminate the body to be examined or to be treated, and those in a second mode of light emitted to display additional Information opposite the first mode colored Light is mixed. Also, funds may be available locally Added mixing colored light to the illumination cone which makes the site to be examined or treated neutral in color, ie illuminated white or whitish and the color-coded additional information in their immediate vicinity, namely still shown within the illumination cone becomes. In particular, the hand instrument has a housing with a handpiece, at the distal end of the illumination cone exit. For this the handpiece contains prefers a light guide, which the illumination light and the colored light to display additional information about the distal End of the handpiece leads. Alternatively, this indicates Enclosure for displaying additional information for an operator of the hand instrument an illuminable segment area on. It is preferred if the illuminable segment area a arranged on the distal end of the handpiece light segment, in particular one arranged at the distal end of the handpiece Includes light ring. Also, the illuminable segment area can continue towards the proximal end of the handpiece or at one the handpiece adjoining hose are arranged where he can be seen out of the corner of the eye for the operator is.

Recently, dental curing devices have been developed that use multiple light sources, such a design including a plurality of LEDs mounted on one or more heat sinks. To effectively dissipate heat from the tip of the dental curing device, which is generated by one or more LEDs, this includes according to the DE 10 2004 061 551 A1 an elongated housing having a proximal end and a distal end, a light source mounted to the far end of the housing, electronic circuitry disposed at least partially within the housing between the proximal end and the far end, a metallic heat sink region adjacent the light source, and extending within a portion of the housing and including a polymer-based heat sink portion adjacent to the metallic heat sink portion and extending within a further portion of the housing. The polymer-based thermal conductive area at least partially surrounds the electronic circuitry and extends within a portion of the wand housing that is gripped by the user during use. The thermally conductive portion of the polymer-based heat sink may be adjacent to the electronic circuitry of the dental curing device without causing problems of electrical conductivity (eg, a short circuit in the electronic circuitry) that would cause a metallic heat sink. Unlike metals, thermally conductive polymer can be introduced into the rod cavity at a relatively low temperature (eg, room temperature) so as to enclose the circuitry without damaging it. Since the heat sink can extend substantially the entire length of the rod, it can effectively dissipate heat from the tip of the dental curing device down to the area of the rod that is gripped by the user. In a further development, the metallic region of the heat sink is separated from the rod housing by an air gap. The air gap provides insulation resulting in less heat diffusion from the rod housing of the dental curing device to the area around the tip of the curing device, resulting in a cooler tip. In addition, at least a portion of the heat-conducting polymer portion of the heat sink may be in direct contact with the rod housing to allow the rod housing to dissipate heat from the patient's mouth and to the portion of the rod housing that is grasped by the dental practitioner. The metallic region of the heat sink may comprise aluminum, brass, copper, steel, silver, or other thermally conductive metals, or a ceramic material based on at least one metal oxide, or a combination thereof. The polymer-based heat sink region may comprise one or more polymers (eg, epoxy or silicone) that are sufficiently thermally conductive to further dissipate heat away from the metallic heat sink region. The polymer-based heat sink region may be in a solid, liquid, gel or other desired physical state. In one embodiment, the polymer or resin is filled with a thermally conductive filler (eg, carbon fibers, graphite particles, ceramic materials, and the like) to increase the thermal conductivity of the polymer-based heat sink region.

It is also known to stick chips for emitting light on a metallic body. Although in such a solution, the thermal resistance between the chip and heat sink is lower than when integrated in a plastic housing / plastic module, yet here, too, the adhesive layer acts as a thermal barrier, so that there is a risk of overheating of the chip or chips. To avoid this is out of the EP 1 228 738 A1 a dental curing device is known in which the semiconductor radiation source is formed as an array of individual radiation sources, which are soldered onto a common base body. The resulting radiant heat on the chip is dissipated via the Wärmeleitverbindung immediately on a fairly large base body, which is then heated but this will be well cooled after he can have a large surface area. In particular, it is provided to arrange each chip in a recess in the base body opposite the surface sunk. This solution results in even further improved light efficiency. The trough is preferably mirrored inside and acts as a micro-reflector, wherein the surface of the light-emitting chip can be arranged in the focal point of the microreflector thus formed. The emitted radiation to the side can be focused in this way, so that the light losses are significantly reduced by misdirection of the radiation. In this context, it is also possible to provide different colors of the emission spectra of the individual chips and to carry out a single control. For example, red light can also be deliberately emitted if a heat treatment is to be carried out by means of the light curing device. In a further preferred embodiment, which is also suitable for high-performance chips, the so-called flip-chip technique can be used. In this case, the contact is made on the underside of the chip and the light output on the top. In this solution, the use of bonded leads is unnecessary after a direct contact can be made, for example by soldering. Furthermore, it is provided to conduct the heat from the base body via a so-called heat pipe to the rear. There, it can be practically dissipated by the ambient air, so that even bladeless can be worked in this solution. The base body can be two in itself be layered, with a metallic surface layer and a ceramic base. In this case, a rather large heat capacity can still be achieved, especially if the metallic surface layer completely surrounds the ceramic body and / or silicon body. The base body can be formed substantially dome-shaped, with a shape that fits exactly into the socket for a previously used halogen incandescent lamp with reflector. The socket has on its outer side cooling ribs, and preferably the base body is then connected via thermal grease to the socket. Replacement is usually not required during the life of the photocuring device after LED chips have a very long life, resulting in savings in maintenance costs compared to the light curing devices with halogen incandescent. Finally, it is provided to intensify the emitted light radiation through a prism body on a cross-section reduced surface. This prism body is designed in such a way that it displaces the light radiation emitted by the individual radiation sources in the outer region of the base body toward the center, so that they can be introduced into the light-conducting rod with virtually no loss. The prism body may also be surrounded on the outside by a heat sink which has longitudinal ribs on its outer circumference, which improve heat dissipation.

Finally, a similar dental curing device with a tubular housing and with various means for cooling the light sources from the WO 2004/0011848 A2 known, whereby the LEDs can be operated with 4 times the power. All described embodiments, the combination of metallic heat sink area and thus in contact heat pipe is common. Specifically, in one embodiment, coolant (eg, water) from the heat sink area is directed by a pump through channels of the heat pipe into the high power LED. In a further embodiment, the heat pipe has a dual function, namely on the one hand to produce an electrical connection between the battery and arranged at the free end of the heat pipe high-power LED and on the other hand, to direct the heat of the LED back to the heat sink area. In another embodiment, a heat sink made of copper is provided for an array of LEDs, which configures a cavity in which the heat pipes are introduced into the cavity and the steam then settles in the cavity. In another embodiment, the LED package is disposed on a conductive substrate which is connected to a heat pipe. In further embodiments, a blower for the heat sink area is provided to improve the cooling capacity or the heat pipe itself is configured at one end as a condenser (cold end) and is cooled by the blower. In another embodiment, between the heat pipe and the tubular housing of the dental curing device, preferably between the center and other free end, provided a material on heating the physical state (from solid to liquid) changing material, such as paraffin or copper wool.

As the above assessment of the state of the art shows, are differently designed medical / dental Hand instruments with a lighting device or dental curing devices known with light. In practice, however, lacks a cost-effective and equipped with commercially available conventional LEDs Hand-held device, which without the use of expensive coolant, For example, heatpipes in combination with heat sinks or additional cooling with fan or design of Kühlmittelkanaälen, a Operation with increased power in a certain temperature range allows. This is particularly important because the medical Equipment manufacturing industry as extreme progressive, development-friendly industry, which quickly picks up on improvements and simplifications and in the act is implemented.

Of the Invention is compared to the known lighting means for handheld devices the task, this way further develop that cost the user a cost manufacturable semiconductor illumination (LED) available which is an operation with increased performance in a certain temperature range allows.

• – eine Halbleiter-Strahlungsquelle mit Gehäusehaube und mit durch eine Grundplatte hindurchgeführte elektrische Anschlüsse,
• – ein an die Grundplatte anschließendes und damit in Kontakt stehendes wärmeleitendes LED-Teil mit Bohrungen für das Durchführen der elektrischen Anschlüsse,
• – ein dem wärmeleitenden LED-Teil nachgeordnetes Kupplungsteil mit Ausnehmungen für das Führen der elektrischen Anschlüsse und
• – eine den noch vorhandenen Raum zwischen Grundplatte der Halbleiter-Strahlungsquelle und LED-Teil einschließlich der Bohrungen ausfüllende Wärmleitsubstanz,

so dass die Kontaktfläche zwischen LED-Teil und Halbleiter-Strahlungsquelle vergrößert ist und die Wärmeableitung zum Kupplungsteil auch über die elektrischen Anschlüsse erfolgt.This object is achieved in an illumination means, in particular for a hand-held device for illuminating a point to be examined or treated, according to claim 1, which comprises:

• A semiconductor radiation source with a housing cover and with electrical connections passed through a base plate,
• A thermally conductive LED part adjoining the base plate and thus in contact with bores for passing through the electrical connections,
• - A the heat-conducting LED part downstream coupling part with recesses for guiding the electrical connections and
• A still existing space between the base plate of the semiconductor radiation source and the LED part including the boreholes filling the heat transfer substance,

so that the contact area between the LED part and the semiconductor radiation source is increased and the heat dissipation to the coupling part also takes place via the electrical connections.

The allows illumination means according to the invention an operation with increased performance in a given Temperature range and is commercially based on the basis LEDs can be produced with low production costs. The spread Heat is provided by heat radiation, heat conduction and heat flow (convection). thermal radiation also allows the release of heat into the vacuum, it depends only on the temperature of the radiating body and regardless of the temperature of the environment. The heat radiation depends on the temperature of the radiator / body and also on the nature of its surface. The Heat conduction occurs only in matter, d. H. in the body, and requires a temperature gradient in it. If a body does not constantly heat in one place feeds or removes, so are all temperature differences in it over time, through a heat flow, which flows from higher to lower temperature. Metals are relatively good heat conductors, for example copper with a thermal conductivity of 0.93 cal / cm · s · k in the temperature range between 0 ° C and 100 ° C or Aluminum with a thermal conductivity of 0.55 cal / cm · s · k in the temperature range between 0 ° C and 200 ° C, while plastics are generally worse Are heat conductors. The heat transfer from a body of a certain temperature to its environment is described by the heat transfer value and the heat transfer through a body, for example a plate is described by the heat transfer value. Of the Heat transfer value depends, as already described above, strongly on the surface texture from and the heat transfer value of the material thickness / plate thickness. The illumination means according to the invention has the advantage of being surprisingly simple and inexpensive Way the ratio of heat transfer value too Heat transfer value (by filling in the remaining Space between base plate of the semiconductor radiation source and LED part including holes with thermal conductivity) was optimized so that a particularly effective heat dissipation is guaranteed.

In Further development of the invention are, according to claim 2, at least portions of the housing cover and the edge region the base plate coated with a thermally conductive varnish or wetted.

These Development of the invention has the advantage that by molding, at least part of the housing cover and the edge region the base plate whose thermal conductivity or Heat capacity is increased. Especially Can spread heat within the body (Housing cover, base plate or LED part) take place thereby, that the base plate on which the housing cover or the LED part is attached or rests, at least one area of increased thermal conductivity by using this as a Component made of a thermally conductive plastic in multi-component injection molding or by molding an insert made of a thermally conductive Plastic or made of metal. In detail, you can to increase the thermal conductivity plastics be compounded with metal or ceramic powders. In cases, where using metal powder, the increased electrical Conductivity of the plastic is undesirable (because of guiding the connections of the semiconductor radiation source), can ceramic fillers such as silicate oxide, Alumina or beryllium oxide are used. Targeted introduced Anisotropies of thermal conductivity with a Preferred direction, z. B. by fibrous fillers, Serve to direct the heat through the component of the body (in particular Base plate and LED part). Alternatively, it is possible only work with an injection molding component and prefabricated Inserts made of thermally conductive plastic or ceramic or metal, e.g. As magnesium or aluminum, to introduce into the plastic.

Further Advantages and details can be found in the following description of preferred embodiments of the invention with reference refer to the drawing. In the drawing shows:

1a and 1b in side view and in perspective, a first embodiment and

2a and 2 B in section a second and third embodiment of the illumination means according to the invention.

1a and 1b show in side view and in perspective a first embodiment of the illumination means according to the invention, which can be used in particular for a hand-held device for illuminating a site to be examined or treated. In this case, a round LEDs in wired form is shown in detail, the illumination means comprises a semiconductor radiation source LED with housing cover GH and passed through a base plate GP electrical connections, a subsequent to the base plate GP and thus in contact heat conductive LED part HS with holes for carrying out the electrical connections, a heat-conducting LED part HS downstream coupling part SO with recesses for guiding the electrical connections and the remaining space between the base plate GP of the semiconductor radiation source LED and LED part HS including the holes ausfüllende Wärmsitsubstanz WL on. If semiconductor radiation source LED with largely square end face of the housing hood GH are used (so-called FormLEDs = rectangular LEDs), then this can be done rows and thus only needs a rectangular opening in the front panel of the device / instrument (area LEDs, ie direct mounting behind the front panel). It can also take into account the fact that the visibility of optical information depends not only on the luminous flux of the source, but at the same luminous flux and on the surface of the light exit. In particular, the rectangles can be strung together seamlessly; When using optical fibers, a small distance between the rectangular outlets is required to avoid crosstalk.

Of the LED part HS is preferably designed such that in the semiconductor radiation source LED absorbed amount of heat absorbed as quickly as possible and can be forwarded in it. LED part and coupling part SO are in particular made of a solid material in milling technology or manufactured by injection molding, and not as usual thin-walled, so by the higher amount of material the heat capacity is maximized. The coupling part SO becomes. according to the specifications of the device / instrument adjusted (so is of the device / instrument and its electrical contacting dependent). By the flat Structure of the surface on the LED side, also touched a standard LED the LED part HS on as large as possible Surface, thereby providing better heat dissipation to LED part HS and coupling part SO towards is achieved. The remaining one Space between the LED part HS and LED (two solids touch only at three points) is caused by the heat transfer substance WL (also networkable) completed. For better mechanical strength In addition, the semiconductor radiation source LED or the base plate GP with the LED part HS are glued together. In particular, the LED part HS is constructed so that by the attachment the thermal conductivity substance WL, this possibility has to capillate in the two holes of the LED part HS and thus the contact area between the semiconductor radiation source LED is enlarged again, so that the heat dissipation to the LED part HS also via the LED connections.

2a and 2 B show in section a second and third embodiment of the illumination means according to the invention. In addition, at least the edge region at the transition between the jacket of the heat-conducting LED part HS and the baseplate GP and / or housing hood GH of the semiconductor radiation source LED is coated or wetted with heat-conducting lacquer W. The heat-conducting lacquer W is transparent (see 2 B ; being compared to in 2a illustrated embodiment, no masking is required) or dyed and can also be applied as a continuous enveloping layer (for example, by dipping). All embodiments have in common that the measures according to the invention, which do not involve a high cost, can also be subsequently applied to conventional light-emitting diodes without the usually long service life of light-emitting diodes being shortened during operation as a high-power light-emitting diode. In particular, a lighting means with heat spreading by Wärmeleitbeschichtung or Wärmeleitsubstanz is realized in a simple manner.

in the Under the invention, at least the housing cover GH to be surrounded by an enclosure and in the thereby designed Space is filled with a liquid; The envelope can be used as a plastic molding with a transparent light passage surface be produced, which at the same time a particularly effective heat dissipation guaranteed; the wrapper may consist of two half-shells exist, which are bonded together by gluing, wherein the lighting means due to the few zusammenzusügenden Parts can be produced fully automatically; the liquid is transparent (eg distilled water) or colored u. a ..

The Invention is not limited to the illustrated and described embodiments but also includes all within the meaning of the invention equivalent designs. Furthermore, the invention so far not yet on the defined in claim 1 feature combination but can also be limited by any other Combination of certain characteristics of all disclosed Be defined individual characteristics. This means that basically virtually every single feature of claim 1 omitted or by at least one elsewhere disclosed in the application Single feature can be replaced.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 69816716 T2 [0002]
• - EP 1093765 A2 [0003]
• - DE 102004006805 A1 [0004]
• - DE 102004061551 A1 [0006]
• - EP 1228738 A1 [0007]
• - WO 2004/0011848 A2 [0008]

Claims (8)

Lighting means, in particular for a handheld device for illuminating a to be examined or body to be treated, which has: A semiconductor radiation source (LED) with housing cover (GH) and with through a base plate (GP) guided electrical connections, - one to the base plate (GP) subsequent and thus in contact vertical heat conducting LED part (HS) with holes for performing the electrical connections, - one the heat-conducting LED part (HS) downstream coupling part (SO) with recesses for passing the electrical Connections and - one remaining Space between base plate (GP) of the semiconductor radiation source (LED) and LED part (HS) including holes filling Thermal conductivity (WL), so that the contact surface Increased between LED part (HS) and semiconductor radiation source (LED) is and the heat dissipation to the coupling part (SO) also over the electrical connections are made. Lighting means according to claim 1, characterized that at least portions of the housing cover (GH) and the Edge area of the base plate (GP) with a heat-conducting lacquer (W) are coated or wetted. Lighting means according to claim 2, characterized that in addition at least the edge area at the transition between jacket of the heat-conducting LED part (HS) and base plate (GP) and / or housing cover (GH) of the semiconductor radiation source (LED) coated with thermal conductive paint (W) or wetted. Lighting means according to claim 2 or 3, characterized in that the heat-conducting lacquer (W) is transparent or colored. Lighting means according to claim 1, characterized that the thermal conductivity substance (WL) is a conductive adhesive or a Conductive paste is. Lighting means according to claim 1, characterized that LED part (HS) and coupling part (SO) made of solid material with good Heat dissipation and heat capacity designed is. Lighting means according to claim 1, characterized that at least the housing cover (GH) of a sheath is surrounded and that in the space designed by a Liquid is filled. Lighting means according to claim 7, characterized that the liquid is transparent or colored is.