JP2012084565A - Heat dissipation sheet and lighting device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat dissipation sheet which can be reduced in tackiness while ensuring heat dissipation, and a lighting device using the same.SOLUTION: A heat dissipation sheet 200 comprises a sheet containing an organic material as a main material, and a metal layer formed on at least one surface of the sheet. A Martens hardness, a creep rate, and an elastic modulus of the sheet are within ranges of 0.01-0.60 N/mm, 0.5-20.0%, and 5.0-30.0%, respectively.

Description

  Embodiments described herein relate generally to a heat dissipation sheet that dissipates heat generated by a light emitting element such as a light emitting diode, and an illumination device that uses the heat dissipation sheet.

  In recent years, electronic devices have been miniaturized, and electronic components are mounted on a substrate at high density. For this reason, the clearance between the electronic components is reduced, and heat radiation generated in each electronic component is a problem. In particular, in a lighting device (LED module) using a light emitting element such as an LED chip (light emitting diode), as the temperature of the light emitting element rises, the light output decreases and the life is affected. For this reason, in an illumination device using a solid light emitting element such as an LED chip or an EL element as a light source, it is necessary to efficiently dissipate the generated heat to suppress the temperature rise of the light emitting element in order to improve the lifetime and the light emission efficiency. is there.

  In a conventional electronic device, in order to improve the heat dissipation of heat generated in the electronic component, between the substrate on which the electronic component is mounted and a heat radiating member (for example, a heat radiating plate or a housing), or between the electronic component and the heat radiating member, In the meantime, it has been proposed to interpose a heat dissipation sheet mainly composed of a silicone gel having high thermal conductivity (see, for example, Non-Patent Document 1).

Fuji Molecular Industry Co., Ltd. homepage, Sircon series, [online], [Search September 27, 2010], Internet <URL: http://www.fujipoly.co.jp/products/sarcon_02_03/xr-j/index .htm>

For example, when the heat dissipation sheet is used in a lighting device, the heat dissipation sheet is used with the heat dissipation sheet sandwiched between a lamp unit and a socket to which the lamp unit is attached. There is a type in which the lighting unit is fixed (twisted and locked) to the socket by rotating (turning) the lamp unit, but the conventional heat radiation sheet has high adhesiveness (tag property), and while rotating the lamp unit Since the heat dissipation sheet does not slip between the lamp unit and the socket when fixed, there is a problem in that the heat dissipation sheet is twisted and heat dissipation is reduced. Further, when the lamp unit is rotated, a shearing force is generated in the heat radiating sheet, so that the durability of the heat radiating sheet is deteriorated and cannot be used repeatedly.
An embodiment of the present invention was made to solve such a problem, and an object thereof is to provide a heat radiating sheet with reduced adhesiveness while securing heat radiating properties and a lighting device using the heat radiating sheet. And

  The heat dissipation sheet according to the embodiment includes a sheet having an organic material as a base material and a metal layer formed on at least one surface of the sheet.

  According to the present invention, since the metal layer is formed on at least one surface of a sheet having an organic material as a base material, it can be expected that adhesiveness is reduced while ensuring heat dissipation.

It is an external appearance perspective view of the illuminating device which concerns on embodiment. It is sectional drawing of the illuminating device which concerns on embodiment. It is a figure for demonstrating the characteristic of a sheet | seat. It is a figure which shows the relationship between the thermal resistance of a thermal radiation sheet, and a load (pressure). It is a figure which shows the change of the thermal resistance of a thermal radiation sheet.

(Embodiment)
An illuminating device according to an embodiment includes a lamp unit including a light emitting unit, a socket that supplies electric power to the lamp unit and that is detachably fixed by rotation, and is interposed between the lamp unit and the socket. And a heat dissipating sheet that transfers heat generated in the lamp unit to the socket. The heat dissipation sheet is pressed at a pressure of 1.85 to 3.00 kPa. The heat dissipation sheet includes a sheet having an organic material as a base material and a metal layer formed on at least one surface of the sheet. Furthermore, the Martens hardness, creep rate, and elastic modulus of the sheet are in the range of 0.01 to 0.60 N / mm ² , 0.5 to 20.0%, and 5.0 to 30.0%, respectively.

  FIG. 1 is an external perspective view of a lighting device 1 according to the embodiment. FIG. 2 is a cross-sectional view of the lighting device 1 according to the embodiment. FIG. 3 is a diagram for explaining the characteristics of the sheet. Hereinafter, with reference to FIGS. 1-3, the illuminating device 1 which concerns on embodiment is demonstrated in detail.

  As shown in FIG. 1, the lighting device 1 according to the embodiment includes a lamp unit 100, a heat radiation sheet 200 that transmits heat generated in the lamp unit 100 to a socket 300, and a socket 300 for attaching the lamp unit 100. . In addition, x in FIG. 1 has shown the ceiling.

(Lamp unit 100)
As shown in FIG. 2, the lamp unit 100 includes an LED chip 101 as a light emitter, a substrate 102 on which the LED chip 101 is mounted, and a control circuit that controls lighting, extinction, dimming, toning, and the like of the LED chip 101. 103, a substrate 104 on which the LED chip 101 is mounted, and a housing 104 that accommodates the control circuit 103, a terminal 105 that receives power and a control signal supplied via a socket 300 described later, and a cover 106.

  One or more LED chips 101 are mounted on the substrate 102 by a chip-on-board method. The number of LED chips 101 mounted is arbitrary. In order to realize white light, three LED chips 101 that emit blue, green, and red light may be mounted on the substrate 102, or LED chips 101 that emit blue light may be mounted on the substrate 102. .

  The substrate 102 is made of a metal, for example, a material having good heat conductivity and excellent heat dissipation, such as aluminum. When the substrate 102 is an insulating material, a ceramic material or a synthetic resin material that has relatively good heat dissipation characteristics and excellent durability can be used. When a synthetic resin material is used, it can be formed of, for example, a glass epoxy resin. Wiring is formed on the surface side of the substrate 102, and the LED chip 101 emits light by electric power supplied from the control circuit 103 via the wiring formed on the surface.

  The control circuit 103 converts an AC voltage 100V supplied via a terminal 105, which will be described later, into a DC voltage 24V, supplies the DC voltage to the LED chip 101 via the substrate 102, and outputs a control signal transmitted via the terminal 105. Based on this, the LED chip 101 is controlled to be turned on / off, dimmed, and toned. The substrate 102 and the control circuit 103 are fixed to the housing 104 by a locking member such as a screw (not shown).

  The housing 104 accommodates the substrate 102 and the control circuit 103 on which the LED chip 101 is mounted, and supports the substrate 102 and the control circuit 103. The housing 104 is provided with an engaging projection 104a (not shown in FIG. 1 because it is on the back side of the lamp unit 100) for fixing the lamp unit 100 to the socket 300. The terminal 105 receives power and a control signal supplied through the socket 300. The cover 106 forms a globe of the lamp unit 100 and is made of a transparent or translucent member having light diffusibility, such as glass or an organic material.

  The heat dissipation sheet 200 includes a sheet 201 having an organic material as a base material and a metal layer 202 formed on one surface of the sheet. The heat radiating sheet 200 has a function of transmitting heat generated in the lamp unit 100 to a heat radiating plate 301 provided in a socket 300 described later.

(Sheet 201)
The sheet 201 is made of a polymer gel sheet containing an inorganic filler. The filler is made of a material having good thermal conductivity and excellent heat dissipation, such as alumina (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), carbon (C), and the like. These fillers may contain what was processed into powder form (particulate form) in the polymer gel.

  The polymer gel sheet is made of silicone or acrylic, and may be hard enough to maintain the shape. Silicone gel is more suitable as a base material for the sheet 201 because it has less change with time than acrylic gel. Moreover, it is preferable that the ratio of the filler added to a polymer gel sheet is 10-80 wt%. When the addition amount is small, the thermal conductivity is lowered, and when the addition amount is too large, the adhesion of the sheet 201 may be impaired.

  Next, the characteristics (Martens hardness, creep rate, elastic modulus) of the sheet 201 will be described with reference to FIG.

(Martens hardness)
Martens hardness is obtained by the measurement method specified in ISO14577-1 Metallic materials-Instrumented indentation test for hardness and materials parameters Part1: Test method "Metal materials-Indentation test for hardness and material parameters" It is a physical property value. This physical property value was calculated using the load and the indentation depth.

The Martens hardness of the sheet 201 is in the range of 0.01 to 0.60 N / mm ² , and more preferably in the range of 0.01 to 0.30 N / mm ² . When the Martens hardness exceeds 0.60 N / mm ² , the sheet 201 becomes too hard to follow the shape of the heat sink 301 of the lamp unit 100 and the socket 300 and exists on the surfaces of the lamp unit 100 and the heat sink 301. It is impossible to fill in the minute unevenness. For this reason, bubbles are generated between the sheet 201 and the lamp unit 100 and between the sheet 201 and the heat dissipation plate 301. This bubble becomes a heat insulating material, and heat cannot be efficiently transferred from the lamp unit 100 to the heat radiating plate 301. Further, when the Martens hardness is less than 0.01 N / mm ² , the sheet 201 becomes liquid or gel, and the change with time due to drying of the liquid component contained in the polymer gel sheet is large, which is not suitable for long-term use.

(Creep rate)
The creep rate (also referred to as indentation creep rate) is the rate of change of depth (indentation depth) when the load is constant for a certain period of time. If the creep rate is C, it is expressed by the following equation (1). .
C = ((h2-h1) / h1) × 100 (1)
In equation (1), h1 is the depth when the set test load is reached (point B in FIG. 3), and h2 is the depth when the set test load is held (point C in FIG. 3).

  The creep rate of the sheet 201 is in the range of 0.5 to 20.0%, and more preferably in the range of 5.0 to 20.0%. If the creep rate is less than 0.5%, the sheet 201 is not easily deformed, so that it cannot follow the shape of the heat sink 301 of the lamp unit 100 and the socket 300, and the minute amount existing on the surfaces of the lamp unit 100 and the heat sink 301 is present. Can not fill the unevenness. For this reason, bubbles are generated between the sheet 201 and the lamp unit 100 and between the sheet 201 and the heat dissipation plate 301. This bubble becomes a heat insulating material, and heat cannot be efficiently transferred from the lamp unit 100 to the heat radiating plate 301. Further, when the creep rate exceeds 20.0%, there is a problem that the sheet 201 is easily deformed and easily cut off by a force applied from the outside.

(Elastic modulus)
The elastic modulus is a physical property value representing the difficulty of deformation, and is a proportional constant between stress and strain within the elastic change. In FIG. 3, the ratio between the depth at the point C and the depth at the point D, that is, the slope of the line segment connecting the points C and D is represented.

  The elastic modulus of the sheet 201 is in the range of 5.0 to 30.0%, and preferably in the range of 5.0 to 15.0%. If the elastic modulus exceeds 30%, the sheet 201 becomes too hard to follow the shape of the heat radiating plate 301 of the lamp unit 100 and the socket 300, and minute irregularities existing on the surfaces of the lamp unit 100 and the heat radiating plate 301 are formed. Can't fill. For this reason, bubbles are generated between the sheet 201 and the lamp unit 100 and between the sheet 201 and the heat dissipation plate 301. This bubble becomes a heat insulating material, and heat cannot be efficiently transferred from the lamp unit 100 to the heat radiating plate 301. On the other hand, if the elastic modulus is less than 5%, the sheet 201 becomes liquid or gel, and the change over time due to drying of the liquid component contained in the polymer gel sheet is large, which is not suitable for long-term use.

(Metal layer 202)
The metal layer 202 is formed on one surface of the sheet 201 in order to ensure slippage (non-tagging) when the lamp unit 100 is fixed to a socket 300 described later by a twist and lock method. By forming the metal layer 202, the frictional resistance with the lamp unit 100 or the heat sink 301 is reduced. For this reason, when the lamp unit 100 is rotated (turned), the heat radiating sheet 200 slides between the lamp unit 100 and the heat radiating plate 301, and the heat radiating sheet 200 also rotates in accordance with the rotation of the lamp unit 100. As a result, the heat dissipation sheet 200 can be prevented from being twisted and deformed.

  Note that the surface on which the metal layer 202 is formed is less likely to follow the minute irregularities (shape) on the surface of the heat radiating plate 301 of the lamp unit 100 or the socket 300, so that the thermal conductivity is higher than when the metal layer 202 is not formed. Will be slightly inferior. Therefore, the metal layer 202 is made of a metal having high thermal conductivity such as aluminum (Al), copper (Cu), iron (Fe), silver (Ag), tin (Sn), Au (gold), or an alloy thereof. Preferably, the thickness is preferably about 10 μm. The metal layer 202 may be formed on both surfaces of the sheet 201, but it is preferable to form the metal layer 202 only on one surface in consideration of thermal conductivity.

The metal layer 202 may be formed by adhering the above-described metal or alloy thin film to the sheet 201 with an adhesive or the like, and is formed using a vapor deposition method in which the above-described metal or alloy is evaporated to adhere to the sheet 201. May be. Alternatively, metal or alloy fine particles may be applied (printed). When the thickness d ₁ of the sheet 201 is smaller than the thickness d ₂ of the metal layer 202, the sheet 201 cannot follow the shape of the surfaces of the lamp unit 100 and the heat sink 301, and the lamp unit 100 and the heat sink 301 It is not possible to fill in minute irregularities present on the surface. For this reason, it is preferable that the thickness d _{1 of the} sheet 201 is larger than the thickness d ₂ of the metal layer 202 (d ₁ > d ₂ ).

(Socket 300)
As shown in FIG. 2, the socket 300 is attached to a ceiling, a wall, or the like, supports the lamp unit 100 in a detachable manner, and supplies power to the lamp unit 100. The socket 300 has a donut shape with a recessed central portion, and an engagement groove 300a that is detachably engaged with the engagement protrusion 104a of the lamp unit 100 is formed in the recess (recess). In addition, the socket 300 is formed with an insertion hole 300 b for inserting the terminal 105 of the lamp unit 100 into the socket 300.

A terminal (not shown) that engages with the terminal 105 of the lamp unit 100 and transmits electric power and a control signal to the terminal 105 of the lamp unit 100 is provided in the insertion hole 300b. The terminal is connected to a power line W _{1 for} supplying power from the outside of the socket 300 and a signal line W ₂ for transmitting a control signal. In addition, the socket 300 includes a heat radiating plate 301 for radiating heat transferred through the socket 200 on the bottom surface of the recess formed in the central portion.

  The heat radiating plate 301 radiates heat generated in the lamp unit 100. For this reason, the heat sink 301 is formed of a metal material or a resin material having a high thermal conductivity. Examples of the metal material include aluminum (Al) and copper (Cu). Moreover, when the heat sink 301 is formed with the resin material, it is preferable to carry out alumite treatment. The heat dissipation effect can be enhanced by anodizing.

  After the engagement protrusion 104a of the lamp unit 100 is aligned with the position of the engagement groove 300a of the socket 300, the convex portion 100a of the lamp unit 100 is inserted into the recess in the center of the socket 300, and the lamp unit 100 is inserted as indicated by the arrow in FIG. By rotating in the direction, the lamp unit 100 is detachably fixed to the socket 300 (twist and lock). In this embodiment, the lamp unit 100 is provided with the engagement protrusion 104a and the socket 300 is provided with the engagement groove 300a. However, the lamp unit 100 is provided with the engagement groove and the socket 300 is provided with the engagement protrusion. It may be.

Next, the effect | action of the illuminating device 1 comprised as mentioned above is demonstrated with reference to FIG.
When power is supplied from the control circuit 103 to the LED chip 101 via the substrate 102, the LED chip 101 emits light. Light generated by the LED chip 101 is emitted from the cover 106. At this time, the lamp unit 100 is heated by the heat generated by the light emission of the LED chip 101, but this heat is radiated from the lamp unit 100 to the heat radiating plate 301 of the socket 300 through the heat radiating sheet 200.

  As described above, the heat dissipating sheet 200 according to this embodiment includes the metal layer 202 made of a metal having high thermal conductivity or an alloy of these metals on one surface of the sheet 201, so that heat dissipation is ensured. Meanwhile, the tackiness can be reduced. For this reason, the frictional resistance between the lamp unit 100 and the heat dissipation plate 301 of the socket 300 when rotating the lamp unit 100 is reduced, and the heat dissipation sheet 200 can be prevented from being twisted and deformed. As a result, the adhesion between the lamp unit 100 and the heat radiation sheet 200 and the adhesion between the heat radiation sheet 200 and the heat radiation plate 301 can be maintained, and the heat radiation performance can be prevented from decreasing.

  Further, when the lamp unit 100 is rotated, the heat dissipation sheet 200 can be prevented from being deformed, so that the generation of shearing force can be prevented and the durability of the heat dissipation sheet 200 can be prevented from being lowered. it can.

Further, the Mantels hardness, creep rate, and elastic modulus of the sheet 201 of the heat dissipation sheet 200 are 0.01 to 0.60 N / mm ² , 0.5 to 20.0%, and 5.0 to 30.0%, respectively. Within the range, more preferably 0.01 to 0.30 N / mm ² , 5.0 to 20.0%, and 5.0 to 15.0%. 100 and the minute unevenness which exists in the surface of the heat sink 301 can be filled.

  For this reason, the contact area between the lamp unit 100 and the heat radiating plate 301 is increased, and the heat generated in the LED chip 101 of the lamp unit 100 can be efficiently radiated to the heat radiating plate 301 of the socket 300. For this reason, the temperature rise of the LED chip 101 of the lamp unit 100 can be suppressed to prevent the light output from decreasing.

Further, the sheet 201 of the heat dissipation sheet 200 is a filler having good thermal conductivity and excellent heat dissipation with respect to organic materials such as acrylic and silicone, such as alumina (Al ₂ O ₃ ), silicon oxide (SiO ₂ ). Since titanium oxide (TiO ₂ ), carbon (C), and the like are added at a rate of 10 to 80 wt%, heat is transmitted through these fillers, so that heat dissipation is further improved.

  Next, specific examples of the sheet according to the embodiment and evaluation results thereof will be described. In addition, in the state which formed the metal layer 202, since it is difficult to measure a Martens hardness, a creep rate, and an elasticity modulus, in the following Examples 1-3 and Comparative Examples 4-8, the metal layer 202 is formed. In other words, the Martens hardness, creep rate and elastic modulus of the sheet alone are measured. Moreover, the Martens hardness, creep rate, and elastic modulus of Examples 1 to 3 and Comparative Examples 1 to 5 were measured at room temperature using a general hardness measuring machine.

The measurement conditions of Martens hardness, creep rate, and elastic modulus are shown below.
Test mode: Load-unloading test test force: 1 mN
Minimum test force: 0.002 mN
Load speed: 3 (0.0500 mN / sec)
Load holding time: 10 sec
Unloading retention time: 0 sec

Example 1
In Example 1, an acrylic gel sheet to which 30 wt% of Al ₂ O ₃ (filler) was added was used as a sheet. The Martens hardness, creep rate, elastic modulus, and thermal resistance of the sheet of Example 1 were 0.20 N / mm ² , 10.0%, 9.0%, and 0.6 ° C./W, respectively.

(Example 2)
In Example 2, a silicone gel sheet added with 40 wt% of Al ₂ O ₃ (filler) was used as the sheet. The Martens hardness, creep rate, elastic modulus, and thermal resistance of the sheet of Example 2 were 0.30 N / mm ² , 6.0%, 30.0%, and 0.7 ° C./W, respectively.

(Example 3)
In Example 3, a silicone gel sheet added with 70 wt% of Al ₂ O ₃ (filler) was used as a sheet. The Martens hardness, creep rate, elastic modulus and thermal resistance of the sheet of Example 3 were 0.5 N / mm ² , 13.0%, 2.0% and 0.3 ° C./W, respectively.

(Comparative Example 1)
In Comparative Example 1, a silicone gel sheet added with 40 wt% of Al ₂ O ₃ (filler) was used as a sheet. The Martens hardness, creep rate, elastic modulus, and thermal resistance of the sheet of Comparative Example 1 were 0.00 N / mm ² , 0.0%, 0.0%, and 0.3 ° C./W, respectively.

(Comparative Example 2)
In Comparative Example 2, an acrylic gel sheet added with 30 wt% of Al ₂ O ₃ (filler) was used as the sheet. The Martens hardness, creep rate, elastic modulus, and thermal resistance of the sheet of Comparative Example 2 were 0.40 N / mm ² , 3.0%, 50.0%, and 1.2 ° C./W, respectively.

(Comparative Example 3)
In Comparative Example 3, a silicone gel sheet added with 40 wt% of Al ₂ O ₃ (filler) was used as a sheet. The Martens hardness, creep rate, elastic modulus, and thermal resistance of the sheet of Comparative Example 3 were 0.70 N / mm ² , 1.0%, 30.0%, and 1.5 ° C./W, respectively.

(Comparative Example 4)
In Comparative Example 4, a silicone gel sheet added with 40 wt% of Al ₂ O ₃ (filler) was used as the sheet. The Martens hardness, creep rate, elastic modulus, and thermal resistance of the sheet of Comparative Example 4 were 0.55 N / mm ² , 0.3%, 30.0%, and 1.8 ° C./W, respectively.

(Comparative Example 5)
In Comparative Example 5, a silicone gel sheet to which 40 wt% of Al ₂ O ₃ (filler) was added was used as a release sheet. The Martens hardness, creep rate, elastic modulus, and thermal resistance of the sheet of Comparative Example 5 were 0.02 N / mm ² , 25.0%, 5.0%, and 1.2 ° C./W, respectively.

  Table 1 lists the measurement results of Martens hardness, creep rate, elastic modulus, and thermal resistance of Examples 1 to 3 and Comparative Examples 1 to 5. Samples A to C in Table 1 correspond to Examples 1 to 3 above, and Samples D to H correspond to Comparative Examples 1 to 5 above.

As apparent from Table 1, the Martens hardness, creep rate, and elastic modulus are in the range of 0.01 to 0.60 N / mm ² , 0.5 to 20.0%, and 5.0 to 30.0%, respectively. For the samples A to C of Examples 1 to 3 in the above, the thermal resistance is 0.6 ° C / W, 0.7 ° C / W, 0.3 ° C / W (less than 1 ° C / W), respectively. It can be seen that good thermal conductivity is obtained.

On the other hand, the comparative example 2 whose Martens hardness, a creep rate, and an elasticity modulus are not in the range of 0.01-0.60 N / mm < ² >, 0.5-20.0%, and 5.0-30.0%, respectively. For the samples E to H of -5, the thermal resistance is 1.2 ° C / W, 1.5 ° C / W, 1.8 ° C / W, 1.2 ° C / W (1 ° C / W or more), respectively It turns out that heat conductivity is inferior compared with sample AC of Examples 1-3.

Sample D of Comparative Example 1 has a Martens hardness, a creep rate, and an elastic modulus of 0.01 to 0.60 N / mm ² , 0.5 to 20.0%, and 5.0 to 30.0%, respectively. The thermal resistance is 0.3 ° C./W (less than 1 ° C./W) although it does not fall within the range, and the thermal conductivity seems to be good. However, the Martens hardness, creep rate, and elastic modulus are 0.0 N / mm ² , 0.0. % And 0.0%, the sheet becomes liquid or gel, and the change over time due to the drying of the liquid component contained in the sheet is so great that it cannot be put into practical use.

  Moreover, since the creep rate of the sample H of Comparative Example 5 is 25%, it seems that the sheet is easily deformed, the adhesion is improved, and the thermal resistance is lowered. However, in practice, the thermal resistance is high. This is because when the creep rate is high, the sheet is easily deformed, so that the sheet is greatly deformed due to the effect of a temporary load at the time of mounting the sheet, and a gap is formed between the substrate and the housing, and the adhesion is This is due to the damage.

As described above, from the results shown in Table 1, the Martens hardness, the creep rate, and the elastic modulus are 0.01 to 0.60 N / mm ² , 0.5 to 20.0%, and 5.0 to 30.0%, respectively. About sample AC of Examples 1-3 which are in the range, it turned out that heat resistance is low and favorable thermal conductivity is obtained.

  FIG. 4 is a diagram showing the results of examining the relationship between the thermal resistance and the load (pressure) of the heat radiation sheet 200. In FIG. 4, the vertical axis represents thermal resistance (° C./W), and the horizontal axis represents pressure (Pa). As the sample in FIG. 4 (hereinafter referred to as a heat dissipation sheet), a sample in which aluminum (Al) was formed to 10 μm on one side of the sample C of Example 3 was used. Moreover, the prescale made from Fuji Film was used for the measurement of load (pressure). The prescale changes in color according to pressure and retains the color after the change. For this reason, it is possible to measure a pressure by observing the color of the prescale after pressurization. In addition, since the prescale serves as a sensor that detects the pressure of the entire film, the balance, distribution, size, and the like of the pressure on the entire plane can be accurately measured.

  As shown in FIG. 4, the thermal resistance is high until the pressure applied to the heat radiating sheet is up to 1850 Pa. However, when the pressure applied to the heat radiating sheet is 1850 Pa or higher, the thermal resistance decreases rapidly, and then the pressure applied to the heat radiating sheet increases. However, it can be seen that the thermal resistance is saturated at about 0.10 (° C./W). From the above, it can be seen that the load (pressure) to the heat dissipation sheet is preferably in the range of 1.85 to 3.00 kPa. If the pressure is less than 1.85 kPa, the thermal resistance is high, and if it exceeds 3.00 kPa, the heat radiating sheet is deformed, and there is a possibility that a gap is formed between the lamp unit 100 and the heat radiating plate 301 of the socket 300 and the adhesion is impaired. Because.

  FIG. 5 is a diagram showing the results of examining changes in the thermal resistance of the heat dissipation sheet. In FIG. 5, the vertical axis represents the rate of increase in thermal resistance (%), and the horizontal axis represents the heating time (hour). The rate of increase in thermal resistance was measured at a temperature of 150 ° C. and a load (pressure) of 2 kPa. As the sample in FIG. 5, the sample C of Example 3 and the sample C of Example 3 formed with 10 μm of aluminum (Al) on the entire surface on one side (heat radiation sheet) were used. In addition, a prescale manufactured by Fuji Film was used for the pressure measurement.

  The thermal resistance increase rate is the value obtained by dividing the thermal resistance of the heat dissipation sheet in the heated state by the thermal resistance (initial value) of the heat dissipation sheet in the unheated state, and how much the thermal resistance has increased or decreased from the initial value. Indicate. When the thermal resistance increase rate is positive (+), it indicates that the thermal resistance has increased from the initial value, and when the thermal resistance increase rate is negative (−), it indicates that the thermal resistance has decreased from the initial value.

  As shown in FIG. 5, it can be seen that there is no significant change in the rate of increase in thermal resistance regardless of the presence or absence of a metal film (aluminum), and that there are good results. In addition, although non-adhesiveness (non-tagging) was also confirmed, there was no problem such as the occurrence of adhesiveness (tagging) on the surface on which the metal film (aluminum) was formed.

  DESCRIPTION OF SYMBOLS 1 ... Illuminating device, 100 ... Lamp unit, 100a ... Convex part, 101 ... LED chip, 102 ... Board | substrate, 103 ... Control circuit, 104 ... Housing, 104a ... Engagement protrusion, 105 ... Terminal, 106 ... Cover, 200 ... Heat dissipation Sheet 201, sheet 202, metal layer, 300 socket, 300a engagement groove, 300b insertion hole, 301 heat sink.

Claims (4)

A sheet based on an organic material;
A metal layer formed on at least one surface of the sheet;
A heat dissipating sheet comprising: The Martens hardness, creep rate, and elastic modulus of the sheet are within a range of 0.01 to 0.60 N / mm ² , 0.5 to 20.0%, and 5.0 to 30.0%, respectively. The heat dissipation sheet according to claim 1, wherein A lamp unit incorporating a light emitting means;
A socket for supplying electric power to the lamp unit, and removably fixing the lamp unit by rotation;
The heat dissipation sheet according to claim 1 or 2, wherein the heat dissipation sheet is interposed between the lamp unit and the socket and transfers heat generated in the lamp unit to the socket.
A lighting device comprising:   The lighting device according to claim 3, wherein the heat dissipation sheet is pressed at a pressure of 1.85 to 3.00 kPa.

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