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EP-3788946-B1 - DEVICE FOR HEAT DISSIPATION AND USE OF SUCH A DEVICE

EP3788946B1EP 3788946 B1EP3788946 B1EP 3788946B1EP-3788946-B1

Inventors

  • Heni, Andreas
  • KUPFERSCHMID, MARKUS
  • Ulmschneider, Daniel
  • Forster, Jonas

Dates

Publication Date
20260513
Application Date
20200820

Claims (15)

  1. Apparatus (10) for heat dissipation, comprising a heat source (12), a heat sink (14) and a heat conducting element (16), wherein the heat conducting element guides heat energy (E) along a heat conducting path (18) from the heat source to the heat sink, and wherein the heat conducting element (16) is arranged on the heat source (12) and on the heat sink (14) in such a way, and changes physically as the temperature of the heat conducting element (16) increases in such a way that a) a first cross-sectional area (A) between the heat source (12) and the heat conducting element (16) and/or a second cross-sectional area between the heat conducting element (16) of the heat sink (14) increases, and/or b) the length (d) of the heat conducting path (18) becomes shorter.
  2. Apparatus according to claim 1, wherein the heat conducting element (16) has a heat pipe (26) or is passed through by a fluid, in order to increase heat dissipation.
  3. Apparatus according to either of the preceding claims, wherein the heat source (12) has a first recess (20) in which a first portion (22) of the heat conducting element (16) is arranged, or the heat conducting element has a first recess in which a first portion of the heat source is arranged.
  4. Apparatus according to any of the preceding claims, wherein the heat sink (14) has a second recess (28) in which a second portion (30) of the heat conducting element (16) is arranged, or the heat conducting element (16) has a second recess in which a second portion of the heat sink (14) is arranged.
  5. Apparatus according to claim 4, wherein the second recess (28) is guided through the heat sink (14) and the heat conducting element (16) is guided through the heat sink (14) in the second recess (28).
  6. Apparatus according to any of the preceding claims, wherein the heat source (12), the heat sink (14) and the heat conducting element (16) are arranged in a straight line, in particular along a common longitudinal central axis (34).
  7. Apparatus according to any of the preceding claims, wherein the heat source (12), the heat sink (14) and the heat conducting element (16) are arranged within a housing, wherein a face (38) of the heat source (12) facing away from the heat conducting element (16) and/or a face (40) of the heat sink (14) facing away from the heat conducting element (16) is arranged on the housing (36).
  8. Apparatus according to claim 7, wherein an image sensor (42) is formed on the face (38) of the heat source (12) facing away from the heat conducting element (16), which image sensor has a visual axis (44) which is directed out of the housing through an opening (46) in a wall (48) of the housing (36).
  9. Apparatus according to any of the preceding claims, wherein the apparatus (10) further has a control element (50) which absorbs heat energy from the heat source (12) and exerts increasing pressure on the heat conducting element (16) as the temperature increases.
  10. Apparatus according to claim 9, wherein the apparatus (10) comprises a lever (52) having a first lever arm (54) and a second lever arm (56), wherein the control element (50) exerts increasing pressure on the first lever arm (54) as the temperature increases, so that the second lever arm (56) exerts pressure on the heat conducting element (16) by means of the heat sink (14).
  11. Apparatus according to any of claims 1 to 8, wherein the apparatus (10) further comprises a control element (62) which absorbs heat energy from the heat source (12) and, as the temperature increases, at least a portion of the control element (62) moves toward the heat conducting element (16) or increases pressure on the heat conducting element (16).
  12. Apparatus according to any of claims 9 to 11, wherein the control element (62) is designed as a first strip (64) and has a counterpart element (66) which is fixedly arranged as a second strip on the control element (62), wherein the counterpart element (66) is made of a material which has a different heat expansion coefficient than the control element (62), wherein the control element (62) is arranged together with the counterpart element (66) in such a way that the control element (62) presses against the heat conducting element (16) with increasing pressure as the temperature increases, and the heat conducting element (16) is optionally designed as a heat conducting pad, the thickness of which decreases as pressure exerted by the control element (62) increases.
  13. Apparatus according to claim 12 or 13, wherein the heat conducting element (16) has a first comb-like element (68) and a second comb-like element (70) which are complementary to one another and mesh with one another, wherein the first comb-like element (68) is arranged on the control element (62) and the second comb-like element (70) is arranged on the heat sink (14), wherein the first comb-like element (68) and the second comb-like element (70) push further into one another as pressure from the control element (62) increases.
  14. Video endoscope (80) comprising an apparatus (10) according to any of the preceding claims, wherein the heat source (12) has an image sensor (42).
  15. Use of an apparatus (10) according to any of the preceding claims for heat dissipation in a video endoscope (80).

Description

The present invention relates to a heat dissipation device comprising a heat source, a heat sink, and a heat-conducting element. The invention further relates to the use of such a heat dissipation device in a video endoscope. In medical technology, monitoring and controlling temperature and heat, the so-called thermal management, presents a major challenge, especially with surgical instruments. Electrical components and the necessary lighting generate waste heat in confined spaces, which can only be dissipated with considerable design effort due to the limited space. US 2017/0258309 A1 Disclosure is of an endoscopic instrument with a heat-generating component that is thermally coupled to a heat sink via a movable contact structure. The movable contact structure accommodates the relative movement between the heat conductor and the heat sink in order to maintain the thermal coupling between these elements and to prevent damage to such thermal coupling when the instrument is exposed to elevated temperatures, for example during autoclaving. US 3,391,728 discloses a heat source and a heat sink separated by liquid metal contained in a sealed housing which includes a bellows and touches the heat source and the heat sink, as well as means which respond to the temperature of the heat source to physically control the pressure on the liquid metal, whereby a reduced pressure causes the liquid heat conductor to be moved away from the interface between the heat source and the heat sink. The object of the present invention is to provide a heat dissipation device that ensures reliable alignment of several electronic components relative to one another, even in confined spaces. Furthermore, a corresponding application is to be demonstrated. According to a first aspect of the invention, the problem is solved by a device for heat dissipation comprising a heat source, a heat sink and a heat conducting element, wherein the heat conducting element carries heat energy from the heat source to the heat sink along a heat conduction path, and wherein the heat conducting element is arranged at the heat source and the heat sink in such a way that a) a first cross-sectional area between the heat source and the heat conducting element and/or a second cross-sectional area between the heat conducting element and the heat sink increases, and/or b) the length of the heat conduction path decreases. In connection with the invention, the inventors recognized that there are particular challenges involved in dissipating heat from two components that need to be positioned precisely relative to each other. With known devices, heat dissipation can be achieved by removing heat from both components, but it is not guaranteed that the components will remain at approximately the same temperature. Such a temperature difference can arise, for example, if the heat flow from the first component (the heat source) to a corresponding heat sink differs from the heat flow from the second component to the heat sink. Furthermore, it is possible that the two components, even if identical in construction, heat up differently. This presents a new challenge, especially for multi-channel endoscopes or exoscopes, where the optimal alignment and adjustment of the two optical channels relative to each other is crucial. A special feature of the invention is that heat dissipation is controlled by a passive design. This utilizes the physical principle that the heat flow between a heat source and a heat sink is greater the larger the cross-sectional area A of the heat path between the heat source at temperature T1 and the heat sink at temperature T2 , and/or the shorter the length d of the heat path. This physical principle is described by the following formula: Q˙=α⋅Ad⋅T1−T2 In this context, the cross-sectional area should be understood specifically as the effective cross-sectional area, and the length specifically as the effective length. This means that the cross-sectional area and/or the length that influences the heat flow according to the formula mentioned above should be considered. Since the device can be implemented using only passive elements, it is particularly suitable for use in confined spaces. Furthermore, the absence of active components allows for exceptionally long, trouble-free operation. It is, of course, possible to equip the device with additional active components for monitoring and control, such as a temperature sensor or a temperature controller for the heat sink. However, for certain applications, the fact that the passive design alone can provide temperature control is considered advantageous. The temperature control works in principle as follows: If the temperature at the heat source rises, the heat transfer element also heats up. The physical properties of the heat transfer element, including its spatial configuration, are chosen such that its physical changes either increase the cross-sectional area of the heat path or shorten the effective length