A DENTAL LIGHT IRRADIATION DEVICE

Abstract

A dental light irradiation device (1) which has a light emitting diode/LED (15) and a heat sink (16) for dissipating heat generated by the LED. The heat sink (16) is formed of a composition which includes a polymer and a filler. The filler provides the composition with increased thermal conductivity relative to the polymer alone. The invention helps maximizing the convenience in handling of dental light devices.

Claims

1. A dental light irradiation device, comprising a light emitting diode (LED) and a heat sink for dissipating heat that is generated by the LED, the heat sink being formed of a composition which comprises a polymer and a filler which provides the composition with increased thermal conductivity relative to the polymer alone.

2. The dental light irradiation device of claim 1, further comprising at least one metal heat dissipation layer which is arranged between the LED and the heat sink for picking up heat generated by the LED, dissipating the heat within the heat dissipation layer and conducting the heat into the heat sink.

3. The dental light irradiation device of claim 1, wherein the heat dissipation layer is formed by an electric conductor for electrically powering the LED.

4. The dental light irradiation device of claim 1, wherein the filler comprises boron nitride.

5. The dental light irradiation device of claim 1, wherein the filler content is within a range of 10% per weight and 60% per weight.

6. The dental light irradiation device of claim 1, wherein the polymer comprises or is formed of a polypropylene, polyethylene, polyamide, polycarbonate, liquid crystal polymer, polyethylene terephthalate, polyphenylene sulfide, polyphthalamide or polybutadiene terephthalate.

7. The dental light irradiation device of claim 1, wherein the composition provides the heat sink with an electric insulating property, the heat sink thus having an electrical resistance of more than 10 000 M.

8. The dental light irradiation device of claim 1, wherein the heat sink supports the LED and forms at least part of a tubular reflector, the LED having an angle of radiation, and wherein the reflector extends circumferentially about a symmetry axis of the angle of radiation.

9. The dental light irradiation device of claim 8, wherein the heat sink forms the reflective surface of the reflector.

10. The dental light irradiation device of claim 1, wherein the heat sink forms at least a portion of an outer surface of the device.

11. The dental light irradiation device of claim 1, wherein the heat sink carries and/or embeds components of electric circuitry for controlling the device.

12. The dental light irradiation device of claim 1, comprising a temperature sensor which sensing portion is embedded within the heat sink.

13. The dental light irradiation device of claim 1, comprising a body which forms toward a rear end of the device a handle portion of the device, and an elongated light output tip toward a front end of the device for emitting light generated by the LED.

14. The dental light irradiation device of claim 13, wherein the light output tip forms a lighting unit adjacent the front end of the device, and wherein the lighting unit comprises the LED.

15. The dental light irradiation device of claim 14, wherein the heat sink extends monolithically between the body and the lighting unit.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0026] FIG. 1 is a cross-sectional view of a dental light irradiation device according to an embodiment of the invention;

[0027] FIG. 2 is a detail view relating to a dental light irradiation device according to an embodiment of the invention;

[0028] FIG. 3 is a perspective view of a heat sink as it may be used with a dental light irradiation device according to an embodiment of the invention; and

[0029] FIG. 4 is a cross-sectional view of a further heat sink and an LED module as they may be used with a dental light irradiation device according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0030] FIG. 1 shows an example of a dental light irradiation device 1 according to the invention. The device 1 has a body 11 and an elongated light output tip 12. The body 11 extends toward a rear end 13 of the device 1 and further forms a handle portion 111. The handle portion 111 allows holding of the device 1 by a user. The light output tip 12 extends toward a front end 14 of the device. The light output tip 12 is shaped and dimensioned so that it can enter a patient's mouth for example for light hardening a dental filling material in one or more of the patient's teeth. The light output tip 12 has a light output 121 for emitting light which is generated by an LED module 15. The LED module 15 in the example comprises at least one high power LED. In particular the LED module 15 is configured for emitting blue light as specified herein.

[0031] The device 1 has a heat sink 16 formed of a composition which comprises a polymer and a filler. The filler provides the composition with increased thermal conductivity compared to the same polymer without the filler. In the example the heat sink 16 extends between the light output tip 12 and the body 11. In particular, the heat sink 16 has a front end 161 which is arranged adjacent the front end 14 of the device 1 and rear end 162 arranged within the body 11. A portion of the heat sink 16 at the front end 161 carries the LED module 15 and further forms a reflector 163 which extends circumferentially around the LED module 15. The reflector is cone-shaped and has a cone, angle of about 50 degrees, widening toward a direction in which the LED module 15 (or the LED) emits light. The angle is measured in a plane through the axis of symmetry of the cone between opposite sides of the reflective surface. The reflector 163 in the example is not coated or mirrored but is provided with the reflective properties by the composition from which the heat sink 16 is made. A further portion of the heat sink 16 at the rear end 162 is configured for carrying electric circuitry 17 for controlling the device 1. The heat sink 16 therefore has means 164 for mechanically retaining the electric circuitry 17 on the heat sink. Such means may comprise pins, screw-holes, retainers and/or other structures, as appropriate.

[0032] The device 1 further has a housing 18 which encapsulates the heat sink 16 with the electric circuitry 17 and the LED module 15. The heat sink 16 is circumferentially spaced from the housing, except for some spacers (not illustrated) which hold the heat sink 16 in place relative to the housing 18. The housing 18 may be generally made of metal except for the light output 121 which is made of a light transmissible (for example transparent) material, like glass or plastic.

[0033] The device 1 in this example further comprises a first knob 21 and a second knob 22. The first knob 21 is an activator for switching the device 1 on or off. The second knob 22 is a selector for pre-selecting an operating time period for which the device 1 operates before it switches off automatically. For the purpose of the present specification switching the device 1 on causes the device 1 to operate and an operation causes the device to emit light via the light output. Further switching the device 1 off causes the device 1 the device to suspend the emission of light via the light output. The device 1 has further functionality which is independent or at least not directly dependent on the operation of the device. The device has, for example, a battery 19, which may be charged or chargeable independent from any operation of the device 1.

[0034] FIG. 2 shows the LED module 15 in more detail. The LED module 15 in this example has a LED semiconductor 151 which is bonded to two conductors 152a, 152b. The LED semiconductor 151 is covered by a transparent lens 155. The lens 155 is preferably formed by an overmold over the semiconductor. Such an overmold may be made of a hardened transparent resin, for example. The conductors 152a, 152b provide for electrically connecting the LED semiconductor 151 with a power source. The conductors 152a, 152b are each configured to comprise or form a heat dissipation layer 153a, 153b. Each heat dissipation layer 153a, 153b is formed by a sheet-like section that is formed by the respective conductor 152a, 152b. Such sheet-like section is relatively flat and forms at least one relatively large major surface. For example, the sheet-like section may be widened with respect to adjacent sections of the conductor in one dimension laterally of a dimension along which the conductor extends. The size in the third dimension of the sheet-like layer may correspond to or may be smaller than the size of the conductor in the same dimension.

[0035] The heat dissipation layers 153a, 153b are arranged with their major surface in contact with the heat sink 16. For example, the heat dissipation layers 153a, 153b may be embedded within the heat sink 16 (not visible in this view). Such an embedding may be achieved by molding the heat sink 16 over heat dissipation layers 153a, 153b. Thus, heat conducted from the LED semiconductor 151 can be transferred by conduction via the relatively large major surface into the heat sink 16. Therefore, the heat can be conveyed into the heat sink 16 relatively rapidly. Further, because the heat dissipation layer 153a, 153b is relatively flat, the heat capacity of the heat dissipation layer 153a, 153b is relatively low so that a relatively low amount of heat is captured in the heat dissipation layers 153a, 153b. The conductors 152a, 152b may be configured as a lead frame or may be part of a circuit board. A circuit board 154 is shown in the example.

[0036] FIG. 3 shows an alternative heat sink 16 that is formed of a composition which comprises a polymer and a filler providing the composition with increased thermal conductivity relative to the polymer alone. The front end 161 of this heat sink 16 is configured to cooperate with a light guide (not shown) that guides light generated at the front end 161 toward a light output. Such a light device is for example disclosed in WO 2010/068435 A1. In this example the LED module (not shown) is arranged on the front end 161 of the heat sink 16. Therefore a portion of the heat sink 16 at the front end 161 may form a reflector (not illustrated) which extends circumferentially around the LED module as described above. The heat sink 16 has a portion at the rear end 162 of the heat sink for carrying electric circuitry (not illustrated) for controlling the device 1. The heat sink 16 therefore has means 164 for mechanically retaining the electric circuitry 17 on the heat sink. Such means in the example comprise screw-holes.

[0037] FIG. 4 shows a further alternative heat sink 16 that is formed of a composition which comprises a polymer and a filler providing the composition with increased thermal conductivity relative to the polymer alone. In this embodiment the LED module 15 has an angled circuit board 154 forming a first portion 154a and a second portion 154b. At least one of the conductors 152a of the LED module 151 continues between the first and second portion 154a, 154b. The LED module 151 is arranged on the first portion 154a of the circuit board 154 and electrically connected to two conductors (of which only conductor 152a is visible in this view). The second portion 154b forms electric circuitry 17 for controlling the device of the invention. The conductor 152a forms a heat dissipation layer at least within a portion of the second portion 154b as described in the example of FIG. 2. Further also the further conductor forms a heat dissipation layer at least within a portion of the second portion 154b as described in the example of FIG. 2. For example, the two heat dissipation layers may be arranged side by side over the full length of the heat sink 16. The length of the heat sink is the dimension of the heat sink 16 between the front end 161 and the back end 162 of the heat sink 16. The heat sink 16 as illustrated in this example may be used in combination with a light guide (not shown) as described in the example of FIG. 3.