Light Source Module

Abstract

The present invention relates to a light source module comprising a light source, which light source module comprises cooling means for cooling the light source base, which light source module further comprises a dechroic reflector, where at least one heat sink surrounds the dechroic reflector. The object of the present invention is to reduce the temperature at the lamp base to increase the lifetime of a lamp. This can be achieved by a light source module that comprises at least a first heat sink, which first heat sink comprises a number of dishes, which dishes are formed to achieve air gabs there between, which dishes comprises at least one opening for the dechroic reflector, which dishes are placed radially around the dechroic reflector, which air gabs between the dishes are directed mostly perpendicularly to a centre axis of the light source module. Hereby, it is achieved that most of the infrared light, which is radiated in the direction of the dechroic reflector is absorbed in the dishes of the heat sink, and because the direction of the dishes is perpendicular to the main axis of the lamp module, the dishes conduct the heat radially towards the outer surface of the dishes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a sectional view of a first possible embodiment of a light source module,

FIG. 2 shows a sectional view of a second possible embodiment of the invention,

FIG. 3 shows a third sectional view of the invention according to a third embodiment of the invention, and

FIG. 4 shows a fourth sectional view of the invention comprising a motor for moving the lamp.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a light source module 2 comprising a light source 4 connected to a light source base 6 where a reflector 7 is placed between the light source 4 and the light source base 6. Cooling means 8 for cooling the light source base 6 is shown which could be in form of means 24 for generating forced air, or a kind of passive means could be used. A lamp socket 9 is connected to the lamp base 6. A dechroic reflector 10 partly surrounds the light source 4 where a heat sink 12 is shown outside the reflector 10. The heat sink 12 is formed of a number of dishes 14 between which dishes 14, air gabs 16 exist. The dishes 14 and also the air gabs 16 are orientated perpendicularly to the centre axis 18 of the light source 2. Between the dishes 14 and the dechroic reflector 10, an air gab 20 is shown.

In operation, the light source module 2 will operate in that the light source 4 generates light which light contains visible light but also have a great amount of infrared light. The dechroic reflector 10 reflects most of the visible light and leads a great part of the infrared light through. The infrared light is, therefore, absorbed by the heat sink 12 because the infrared light which passes through the reflector 10 heats the dishes 14 where most of the infrared light is absorbed. A further reflector 7 reflects visible light as well as infrared light back towards the light generating means 4 or the heat sink 12. In this way, the light source base 6 is prevented from being heated up by the radiation generated by the light source 4. The dishes 14 of the heat sink 12 are heated by the absorbed infrared light, and the dishes heat the air there between so the convectional flow of air will start in the air gabs 16 between the dishes 14. This air flow will also start a circulation of air in the air gab 20 between the dechroic reflector 10 and the dishes 14. Also around the reflector 7, an air flow will start probably because the convectional air flow through the air gabs 16 will generate a lower pressure around the light source 4 so air will be forced around the reflector 7 towards the light source 4. This assures a constant air flow towards and around the light source base 6 which is then kept at a relatively low temperature which will reduce the oxidation of the electrical terminals 50, 52. If a high temperature occurs at the terminals 50, 52, an oxidation will take place along the terminals 50, 52 through the glass bulb, and corrosion will start and reduce the cross section of the connectors. The corrosion might generate a small opening towards the filament 54 inside the glass bulb. As soon as oxygen has access to the inside of the bulb, a light source will be destroyed. Another possible destruction is simply that the corrosion reduces the cross-sectional of the terminal so that the electrical resistance increases, and the terminal is burned away which is also destructive to the light source.

FIG. 2 shows the same elements with the same reference numbers as used in FIG. 1 with the difference that cooling means 8 is formed by a second heat sink 22 which heat sink comprises dishes 60 where air gabs 62 are formed between these dishes.

The functions of the invention shown in FIG. 2 are mostly like the one described in FIG. 1, and it only differs in the use of the heat sink 22. The light source base 6 will in all circumstances be heated to a certain extent because the terminals 50, 52 are heat conductive. Also electrical resistance might occur in these terminals, and the way the terminals are connected to the lamp socket 9 might result in a small electrical resistance which leads to heating. Heat will be radiated from the light source base 6 towards the dishes 60, and an air flow will be generated in the air gabs 62 between the dishes 60. This can lead to an air flow around the light source base 6 which in this way is cooled to a temperature below the specified maximum temperature for the light source base which will increase the lifetime of the light source 4.

FIG. 3 shows a third embodiment of the invention 202, which differs from FIG. 1 and FIG. 2 in that a housing 26 surrounds the light source base 6. Connected to the housing 26, means 24 for generating forced air is shown which means 24 could be in form of a small blowing unit which through an opening 28 in the housing 26 blows air towards the light source base 6. This also leads to an increasing pressure in the light source housing 26. A further difference to FIG. 1 and FIG. 2 is that a reflective heat filter 32 is shown in front of the dechroic reflector 10. This heat filter 32 is in two parts having an angle towards the centre axis 18 of the light source module where a third heat sink 70 continues where the first heat sink 12 ends. The third heat sink 70 is formed of dishes 72, and between these dishes, air gabs 74 are formed.

The reflective heat filter 32 reflects most of the infrared light contained in the light beam generated by the light source 4 and reflected by the dechroic reflector 10. Infrared light is reflected from the reflective heat filter 32 towards the heat sink 70 and towards the heat sink 12. In this way, it can be achieved that a very limited content of infrared light exists in the light beam that is delivered from the light source module and most of the heat generated by the infrared light is conducted away from the light source 4 and the light source base 6. The reflective heat filter can comprise more three angel formed filters forming a high number of reflective surfaces. Hereby the reflected infrared light is directed towards most of the dish formed heat sink. Even a conical formed mirror could be used for reflecting the infrared light. This will give a uniform distribution of the reflected infrared light over the dish formed heat sink

By assuring a higher pressure inside the housing 26, an air stream will be generated around the reflector 7 and into the air gab 20, by using the means 24 for generating forced air, the light source module could be used in every orientation without a critical increase of temperature in the light source base 6.

FIG. 4 shows the same elements as previous described with references to FIGS. 1-3 which are not repeated.

FIG. 4 shows a motor 80 connected to a spindle 82. The spindle cooperates with a screw 84 fixed to a fixture 90 where the lamp socket is fixed to the fixture. The motor is connected to the housing 26. Also connected to the housing, governing means 86 is shown which cooperates with sliding means 88 connected to the fixture 90.

Hereby, it is achieved that the position of the lamp can be controlled. An electronic control signal coming from a computer might control the movement of the motor. The effective cooling means around the lamp decreases the temperature inside the housing 26 to a level where a step motor can operate.

FIG. 5 shows an alternative embodiment for the inventions comprising the same elements as previous described with reference to FIG. 14, which are not repeated in the following.

The FIG. 5 shows a light trap 40, which stops visible light 104 from the lamb, so that the open heat sink 12 remains relatively dark during operation. The FIG. 5 also shows arrows indicating visible light 104 and IR light 106. IR light 106 is reflected back from the reflector 22 towards the reflector 10, where the IR light 106 passes through and is absorbed at dishes 14. Further the FIG. 5 contains arrows indicating the airflow 108. The figure shows air flow 108 on both sides of the reflector 10, and from the backside of the reflector 10 the air flow 108 into the openings 15 between the dishes 14.

Herby is achieved a highly effective cooling of the lamb 4 and the lamp socket 9. This will increase the lifetime of the lamp.

Claims

1. A light source module (2) comprising a light source (4), which light source is connected through a light source base (6), which light source module (2) comprises cooling means (8) for cooling the light source base (6), which light source module (2) further comprises a dechroic reflector (10), where at least one heat sink (12) is surrounding the dechroic reflector (10), characterised in that the light source module (2) comprises at least a first heat sink (12), which first heat sink (12) comprises a number of dishes (14), which dishes (14) are formed to achieve air gabs (16) there between, which dishes (14) comprises at least one opening for the dechroic reflector (10), which dishes (14) are placed radially around the dechroic reflector (10), which air gabs (16) between the dishes (14) are directed mostly perpendicularly to a centre axis (18) for the light source module (2), where the light source module comprises a further air gab (20) between the dechroic reflector (10) and the dish formed heat sink (12) where the said air gab (20) between the dechroic reflector (10) and the dish formed heat sink (12) is open towards the air gabs (16) between the dishes 14).

2. A light source module according to claim 1, characterised in that the cooling means for the light source base comprises a second heat sink (22), which heat sink (22) is cooled by air convection.

3. A light source module according to claim 1, characterised in that the cooling means (8) for the base comprises means (24) for generating a forced air flow around the light source base (6).

4. A light source module according to claim 3, characterised in that the light source base (6) is placed in a housing (26), which housing (26) comprises an inlet (28) for forced air and an outlet (30) connected towards the air gab (20) between the dechroic reflector (10) and the dish-shaped heat sink (12).

5. A light source module according to claim 1, characterised in that the light source module (2) comprises at least one heat filter (32) in the light path, which heat filter (32) reflect infrared light towards the heat sink (12).

6. A light source module according to claim 1, characterised in that the front (34) and rear surface (36) of the dish-shaped heat sink (12) are isolated by isolation means (38) towards other light source components.

7. A light source module according to claim 1, characterised in that the air gabs between the dishes forming the heat sink comprises a light trap (40) for collecting infrared radiation.

8. A light source module according to claim 1, characterised in that the housing (26) that surrounds the light source base (6) comprises at least one motor (42) for adjusting the position of the light source (4).

9. A light source module according to claim 8, characterised in that the light source base (6) is adjustable in the X, Y and Z direction by step motors (44, 46, 48) connected to internal or external control means.

10. Method for cooling a light source module, which light source module comprises a light source and a light source base which light source is surrounded by reflective means for reflecting visible light and passing infrared light towards a heat conducting heat sink for conducting absorbed heat from a light source towards the surroundings, characterised in that the heat sink is conducting the heat mostly into radial direction towards the outside of the light source module by a dish formed heat sink, where the dishes are directed mostly perpendicular to the centre axis of the light source module, where the light source module comprises a further air gab between the dechroic reflector and the dish formed heat sink where the said air gab between the dechroic reflector and the dish formed heat sink is open for air flow towards the air gabs between the dishes.