JP2011103261A - Light source unit using light-emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source unit using light-emitting elements, wherein a plurality of light-emitting elements that constitute a light-emitting source can be cooled efficiently with high uniformity, thereby suppressing decline in the light emitted intensity, as well as, uneven illumination at the face to be illuminated. <P>SOLUTION: The light source unit using light-emitting elements includes a heat sink upon which a plurality of light-emitting units, with each of which being constituted of one or more light-emitting elements, are arranged at the top face thereof. The heat sink is provided with one or more cooling flow paths for allowing a cooling medium flow on one or the plurality of light-emitting units at an upper-face side level of the heat sink. Flow-in ports and flow-out ports for the cooling medium provided within the cooling flow paths are connected to a supply flow path and a discharge flow path for the cooling medium which are formed at level lower than a face-side level of the heat sink than the cooling flow paths. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light-emitting element light source unit including a plurality of light-emitting portions composed of light-emitting elements such as LED (Light Emitting Diode) elements, and more particularly, to be suitably used as a fixing light irradiator in a photo-curable inkjet printer apparatus. The present invention relates to a light-emitting element light source unit that can

Recently, in a photo-curable ink jet printer apparatus, a light emitting device such as an LED element is used as a fixing light irradiator (see, for example, Patent Document 1), and the LED element emits light. A fixing light irradiator as a source is usually configured by arranging a large number of LED elements at a high density in order to obtain a desired light emission intensity.
However, in such a fixing light irradiator, heat is generated as the LED element emits light, and 80 to 90% of the input power is converted into heat. Each of the LEDs easily rises in temperature due to its own heat generation or heat received from the surroundings, and the light emission efficiency of the LED element itself is lowered due to this.
In other words, when the luminous efficiency of some of the LED elements constituting the fixing light irradiator is reduced, the illuminance unevenness occurs on the irradiated surface. Will cause poor fixing locally. Further, when the light emission efficiency is lowered in all of the many LED elements constituting the fixing light irradiator, fixing failure occurs over the entire printed image to be obtained.

On the other hand, in order to dissipate the heat generated from the LED element, it is proposed to cool the LED element by arranging the LED element on a heat sink in which a circulation channel for circulating a cooling medium is formed. (For example, see Patent Document 2).
In Patent Document 2, as shown in FIG. 11, the flow passage 65 is specifically disposed on the heat sink 67 so as to be close to each of a plurality (five in FIG. 11) of LED elements 66. The plurality of LED elements 66 are meandered so as to pass through all regions immediately below them.

However, in order to cool the LED element with high efficiency by the heat sink provided with the circulation channel of the cooling medium, the thermal resistance is reduced by providing the circulation channel in the vicinity of the LED element, and the cooling medium of the heat sink Since it is necessary to increase the contact area of the heat sink with the cooling medium in order to increase the efficiency of heat conduction between the two, the following problems arise when trying to cool a large number of LED elements.
That is, as the flow path length of the flow path becomes longer and the required flow rate of the coolant increases, the pressure loss increases, so that the required amount of coolant can be circulated in the flow path. Therefore, the flow rate of the cooling medium is reduced, and accordingly, the contact area between the cooling medium and the heat sink is reduced, and the LED element cannot be sufficiently cooled.
In addition, in the flow channel, a large temperature difference occurs between the cooling medium on the upstream side and the downstream side, that is, a large temperature gradient occurs, so that a large number of LED elements cannot be uniformly cooled.

JP 2007-210167 A JP 2005-338251 A

  The present invention has been made based on the circumstances as described above, the purpose of which can efficiently and efficiently cool a plurality of light emitting elements constituting a light emitting source, An object of the present invention is to provide a light emitting element light source unit capable of suppressing a decrease in light emission intensity and generation of illuminance unevenness on a light irradiated surface.

The light emitting element light source unit of the present invention is a light emitting element light source unit including a heat sink in which a plurality of light emitting units each including one or more light emitting elements are positioned on the upper surface.
The heat sink includes a cooling channel for circulating a cooling medium corresponding to one or a plurality of light emitting units on the upper surface side level, and an inlet and an outlet of the cooling medium in the cooling channel are respectively It is connected to a cooling medium supply channel and a cooling medium discharge channel formed at a lower surface side level than the cooling channel.

In the light emitting element light source unit of the present invention, the heat sink is provided with a plurality of cooling channels, and the inlet and outlet of each of the plurality of cooling channels are a common supply channel and a common discharge channel. It is preferable that they are connected.
In the light emitting element light source unit having such a configuration, the length of the path from the most upstream position of the supply flow path to the most downstream position of the discharge flow path via the cooling flow path is the same for each cooling flow path. It is preferable that

  In the light emitting element light source unit of the present invention, it is preferable that the cooling flow path is annular, and the inlet and outlet of the cooling medium are provided at symmetrical positions.

  In the light emitting element light source unit of the present invention, it is preferable that all the light emitting elements constituting the plurality of light emitting portions are arranged in the region immediately above the cooling flow path.

  The light-emitting element light source unit of the present invention is used as a fixing light irradiator of a photocurable ink jet printer apparatus.

In the light emitting element light source unit of the present invention, the flow path of the cooling medium provided in the heat sink includes a cooling flow path, a supply flow path, and a discharge flow path, and the supply flow path and the discharge flow path are The cooling medium flowing through the supply flow path rises in temperature due to heat received from the light emitting element because it is disposed at the lower surface side than the cooling flow path, that is, at a position level away from the upper surface where the light emitting element is disposed. Therefore, a large temperature gradient does not occur in the supply channel. Moreover, due to its structure, a plurality of cooling flow paths can be connected in parallel by the supply flow path and the discharge flow path, thereby allowing the cooling medium to circulate corresponding to the light emitting section without causing a large pressure loss. Since the total flow path length of the cooling flow path can be increased, the required amount of cooling medium can be circulated, and the contact area between the cooling medium and the heat sink can be increased, Since a cooling medium having the same temperature as that of the upstream side of the supply flow path can flow into each cooling flow path, the light emitting element can be cooled with the cooling medium with high efficiency.
Therefore, according to the light emitting element light source unit of the present invention, the plurality of light emitting elements constituting the light emitting source can be cooled efficiently and with high uniformity, thereby reducing the emission intensity and reducing the light irradiation surface. Generation of uneven illuminance can be suppressed.

It is an explanatory perspective view which shows an example of a structure of the light emitting element light source unit of this invention. It is an expanded sectional view for description of the light emitting element light source unit of FIG. It is an expansion perspective view for description which shows the front side of the light source module which comprises the light emitting element light source unit of FIG. It is a perspective view for explanation which shows the back side of the light source module which constitutes the light emitting element light source unit of FIG. It is explanatory drawing which shows the state which looked at the front of the light source module which comprises the light emitting element light source unit of FIG. 1 from upper direction. It is explanatory drawing which shows typically the heat sink which comprises the light emitting element light source unit of FIG. 1, (a) is explanatory drawing which shows the state which looked at the flow path of the cooling medium currently formed in the heat sink from the upper direction, (A) is explanatory drawing which shows the state which looked at the flow path of the cooling medium currently formed in the heat sink from the one side surface side. It is explanatory drawing which shows an example of a structure of the principal part of the photocurable inkjet printer apparatus which used the light emitting element light source unit of this invention as a light irradiation device for fixing. It is explanatory drawing which shows typically the heat sink which concerns on the other structure of the light emitting element light source unit of this invention, (a) is explanatory drawing which shows the state which looked at the flow path of the cooling medium currently formed in the heat sink from the upper direction (A) is explanatory drawing which shows the state which looked at the flow path of the cooling medium currently formed in the heat sink from the one side surface side. It is explanatory drawing which shows typically the heat sink which comprises the light emitting element light source unit used in the comparative experiment example 1, (A) is the description which shows the state which looked at the flow path of the cooling medium currently formed in the heat sink from the upper direction. (A) is explanatory drawing which shows the state which looked at the flow path of the cooling medium currently formed in the heat sink from the one side surface side. It is a graph which shows the relationship between the flow volume of the cooling medium in Example 1 and a comparative example, and a pressure loss. It is explanatory drawing which shows the structure of the heat sink for cooling the LED element arrange | positioned in the upper surface conventionally used.

Embodiments of the present invention will be described below.
1 is an explanatory perspective view showing an example of the configuration of the light emitting element light source unit of the present invention, FIG. 2 is an enlarged sectional view for explaining the light emitting element light source unit of FIG. 1, and FIG. FIG. 4 is an explanatory enlarged perspective view showing a front surface (light emitting surface) side of a light source module constituting the light emitting element light source unit of FIG. 4, and FIG. 5 is a perspective view, and FIG. 5 is an explanatory view showing a state in which the front surface of the light source module constituting the light emitting element light source unit of FIG. 1 is viewed from above.
The light-emitting element light source unit 10 uses the light-emitting element 23 as a light-emitting source, and is used as, for example, a fixing light irradiator in a photo-curable ink jet printer apparatus. The arranged rectangular substrate 21 includes a light source module 11 configured to be positioned on the upper surface (upper surface in FIG. 3) of the heat sink 30 having a substantially U-shaped appearance. It is configured to be covered with an aluminum cover member 13. The cover member 13 is provided with a power supply connector 18 for connecting to an external power source and a light irradiation window 17 made of borosilicate glass for protecting the light emitting element 23 provided on the substrate 21. Further, the outer surface of the cover member 13 is subjected to black alumite treatment from the viewpoint of preventing light scattering, and is provided on the region of the inner surface from the substrate 21 to the light irradiation window 17, that is, the substrate 21. In the region 13A surrounding the space where the light path from the plurality of light emitting elements 23 to the light irradiation window 17 is formed, the light from the plurality of light emitting elements 23 is transmitted from the light irradiation window 17 with high efficiency. Mirror finish is given from the viewpoint of radiation.
In the example of this figure, the substrate 21 is fixed to the upper surface of the heat sink 30 by screws 19, and heat transfer grease is applied between the substrate 21 and the heat sink 30 from the viewpoint of thermal conductivity.

On the surface of the substrate 21, a plurality (48 in the example in the figure) of light emitting units 22 are arranged in two rows at equal intervals (a pitch of 4.6 mm in the example in the figure). A plurality (six in the illustrated example) of connectors 24 for supplying power to the light emitting elements 23 constituting the light emitting unit 22 are provided on the back surface.
In the example of this figure, each of the plurality of light emitting units 22 is composed of one light emitting element 23, and eight light emitting elements 23 constituting these light emitting units 22 are electrically connected in series. The eight light emitting elements 23 connected in series are electrically connected to one connector 24.

As the light emitting element 23, an LED element, an LD element (laser diode element) or the like is used. Specifically, for example, those having peak emission wavelengths of 365 nm, 385 nm, 405 nm, and 450 nm are used as the LED element.
In the example of this figure, an LED element is used as the light emitting element 23.

As a base material which comprises the board | substrate 21, the appropriate thing according to the kind etc. of the light emitting element 23 is used, For example, the thing made from aluminum nitride etc. can be used.
In the example of this figure, a substrate made of aluminum nitride having a width of 16 mm, a length of 113 mm, and a thickness of 0.6 mm is used.

The heat sink 30 is for cooling the light emitting element 23 constituting the light emitting unit 22 located on the upper surface. For example, the heat sink 30 has, for example, cooling water in a heat sink body 31 having a substantially U-shaped appearance made of copper. A flow channel for circulating a cooling medium such as a supply channel 34 for supplying a cooling medium to the flow channel, and a discharge for discharging the cooling medium from the flow channel are formed. The portion 35 is provided in a region other than the region where the substrate 21 is located on the outer surface of the heat sink main body 31.
In the example of this figure, the supply part 34 is formed at the end of one protrusion (left side in FIG. 3) of the heat sink main body 31, and the discharge part 35 is formed at the end of the other protrusion.

Then, in the heat sink 30, the cooling medium flow path is, as shown in FIG. 6, a cooling flow path 45 provided parallel to the upper surface of the heat sink 30 at the upper surface side level in the upper surface side portion 32 of the heat sink 30. A supply flow path 43 and a discharge flow path 44 provided in parallel to the upper surface of the heat sink 30 are provided at the lower surface side level in the lower surface portion 33 located on the lower surface side of the cooling flow channel 45. . As described above, the cooling flow path 45 formed at different position levels in the thickness direction of the heat sink 30, the supply flow path 43 and the discharge flow path 44 are the cooling medium inlet formed in the cooling flow path 45. 46 and the outlet 47 respectively communicate with the supply channel 43 through an inflow path 48 extending in the thickness direction of the heat sink 30, while an outflow path 49 in which the outlet 47 extends in the thickness direction of the heat sink 30. Are connected by communicating with the discharge flow path 44 via.
In the example of this figure, the supply channel 43 is connected to the supply unit 34 via a supply channel 41 extending in the thickness direction of the heat sink 30 at a supply opening 43A formed at one end thereof, and the discharge channel 43 44 is connected to the discharge part 35 through a discharge path 42 extending in the thickness direction of the heat sink 30 in a discharge opening 44A formed at one end thereof.

The cooling channel 45 is for circulating a cooling medium corresponding to the light emitting unit 22 on the substrate 21, and in this cooling channel 45, heat of the light emitting elements 23 constituting the light emitting unit 22 is transferred to the substrate 21 and the cooling channel 45. Heat is received by the cooling medium via the heat sink body 30, and the light emitting element 23 is thereby cooled.
In the example of this figure, the cooling channel 45 has a rectangular shape with a cross-sectional shape having a width of 3 mm and a height of 1 mm.

Further, from the viewpoint of increasing the cooling efficiency of the heat sink 30, a plurality of cooling channels 45 are provided according to, for example, the number and arrangement state of the light emitting elements 23 constituting the plurality of light emitting units 22 on the substrate 21. It is preferable that
In the case where a plurality of cooling channels 45 are provided, these plurality of cooling channels 45 preferably have the same shape (specifically, the overall shape and the cross-sectional shape).
In the example of this figure, three cooling channels 45 are provided so as to correspond to a total of 16 light emitting elements 23 arranged in two rows, respectively, and these three cooling channels 45 45 has the same shape.

The cooling channel 45 is provided at a position level close to the upper surface of the upper surface side portion 32 of the heat sink 30 from the viewpoint of increasing the cooling efficiency by reducing the thermal resistance between the light emitting element 23 and the light emitting element 23. It is preferable.
In the example of this figure, each of the cooling channels 45 is formed so that the depth from the upper surface of the heat sink 30 is 1 mm, that is, the distance from the upper surface is 1 mm.

In addition, the cooling flow path 45 is preferably provided so that all of the light emitting elements 23 constituting the plurality of light emitting units 22 in the substrate 21 are arranged in a region immediately above the cooling flow path 45.
By arranging all the light emitting elements 23 constituting the plurality of light emitting units 22 in the region immediately above the cooling flow path 45, the thermal resistance between the cooling flow paths 45 is made uniform in each of the plurality of light emitting elements 23. Can be achieved.

The shape (the entire shape) of the cooling channel 45 is not limited. However, the cooling channel 45 is preferably annular, and in the case of an annular shape, the inlet 46 and the outlet 47 are connected to the cooling channel 45. It is preferable that they are provided symmetrically with respect to the center point of the ring.
Since the entire shape of the cooling channel 45 is annular, the cooling medium flowing in from the inlet 46 has two paths toward the outlet 47, that is, two branch paths are formed in the cooling channel 45. In addition, since the inlet 46 and the outlet 47 are in a symmetrical position, the length of the path from the inlet 46 to the outlet 47 in each of the two branch paths is the same. The cooling efficiency for each of the plurality of light emitting elements 23 by the cooling medium can be increased and made uniform.
In the example of this figure, the cooling channel 45 has a rectangular shape as a whole, and the inflow port 46 and the outflow port 47 are symmetrical positions corresponding to the respective midpoints on the two long sides of the rectangle. Is formed.

  As a specific example of the overall shape of the cooling channel and the formation position of the inlet and outlet, in addition to the example in this figure, for example, the overall shape is a rectangular ring, and the inlet and outlet are symmetrical on the diagonal line. Are formed in various positions, the entire shape is annular, the inlet and the outlet are formed in symmetrical positions, and the entire shape is U-shaped, and flows at one end. Examples include an inlet formed and an outlet formed at the other end.

Moreover, it is preferable that the cooling flow path 45 is provided with many columnar portions extending in a direction perpendicular to the flow direction of the cooling medium.
By providing a large number of columnar portions in the cooling flow path 45, the contact area between the heat sink 30 and the cooling medium in the cooling flow path 45 can be increased, and the cooling medium in the cooling flow path 45 can be increased. Since the flow can be turbulent, heat transfer between the heat sink 30 and the cooling medium can be increased.
In the example of this figure, the cooling flow path 45 extends in the thickness direction of the heat sink 30 (vertical direction in FIG. 3), and each end thereof is joined to the mutually opposing wall surfaces of the cooling flow path 45. A large number of columnar portions are formed.

In the supply flow path 43 and the discharge flow path 44, the supply flow path 43 circulates the cooling medium toward the inlet 46 of the cooling flow path 45, while the discharge flow path 44 is an outlet 47 of the cooling flow path 45. In the case where a plurality of cooling channels 45 are provided, a common supply to the plurality of cooling channels 45, that is, a common supply of the plurality of cooling channels 45 is provided. By connecting to the flow path 43 and the common discharge flow path 44, these cooling flow paths 45 can be connected in parallel.
These supply flow path 43 and discharge flow path 44 preferably have the same shape (specifically, the overall shape and the cross-sectional shape) and are provided in parallel.
In the example of this figure, each of the supply flow path 43 and the discharge flow path 44 is a rectangular shape having an overall shape of a straight line and a cross-sectional shape of a width of 2.5 mm and a height of 5 mm.

In the flow path of the cooling medium configured such that the plurality of cooling flow paths 45 are connected in parallel by the supply flow path 43 and the discharge flow path 44, the cooling medium supplied from the supply unit 34 reaches the discharge unit 35. Are formed by the number of the cooling flow paths 45 connected in parallel by the supply flow path 43 and the discharge flow path 44, and the plurality of paths are the most upstream of the supply flow path 43. The length of the path from the supply opening 43A, which is the position, to the discharge opening 44A, which is the most downstream position of the discharge flow path 44, via the cooling flow path 45 is about each of the plurality of cooling flow paths 45. Are preferably the same.
In the example of this figure, between the supply opening 43A and the discharge opening 44A, the cooling flow path 45A located on the most upstream side of the supply flow path 43 and the cooling located on the most downstream side of the supply flow path 43. The three cooling channels 45, that is, the channel 45 C and the cooling channel 45 B positioned between the cooling channel 45 A and the cooling channel 45 C, are provided between the supply channel 43 and the discharge channel 44. Two branch paths are formed, thereby forming three paths having the same lengths: a path passing through the cooling flow path 45A, a path passing through the cooling flow path 45B, and a path passing through the cooling flow path 45C. Has been.

  Since all the lengths of the path from the supply opening 43A to the discharge opening 44A through each of the plurality of cooling flow paths 45 are the same, the flow path resistance in each path becomes equal. Therefore, an equal amount of cooling medium flows into each of the plurality of cooling channels 45, that is, the cooling medium supplied from the supply channel 41 to the supply channel 43 is supplied to each of the plurality of cooling channels 45. Can be distributed evenly.

  In the light emitting element light source unit 10 as described above, the cooling medium is supplied from the supply unit 34 to the heat sink 30 and supplied from the supply unit 34 in a state where the light emitting element 23 constituting the light source is emitting light. The cooled cooling medium is distributed and introduced into each of the plurality of cooling channels 45 via the supply channel 41 and the supply channel 43, and after passing through each of the plurality of cooling channels 45, the discharge channel 44. In addition, the cooling medium is discharged from the discharge portion 35 to the outside of the heat sink 30 through the common outflow path 42, and the cooling medium flows in the heat sink 30 in this way, thereby the cooling medium flowing through the heat sink body 31 and the cooling flow path 45. Each of the light emitting elements 23 is cooled.

Thus, the flow path of the cooling medium provided in the heat sink 30 constituting the light emitting element light source unit 10 includes the cooling flow path 45, the supply flow path 43 and the discharge flow path 44, and the supply flow path 43 and the discharge channel 44 are disposed at a position level away from the upper surface where the light emitting element 23 on the lower surface side of the cooling channel 45 is disposed, so that the cooling medium flowing through the supply channel 43 is Since the temperature rise due to heat received from the light emitting element 23 is suppressed, a large temperature gradient does not occur in the supply flow path 43.
Moreover, the heat sink 30 has a structure in which a plurality of cooling flow paths 45 are connected in parallel by the supply flow path 43 and the discharge flow path 44 in accordance with, for example, the number and arrangement state of the light emitting elements 23 constituting the light emission source. As a result, the total flow path length of the cooling flow path for circulating the cooling medium corresponding to the light emitting section 22 can be increased without causing a large pressure loss. An amount of the cooling medium to be circulated, and the contact area between the cooling medium and the heat sink 30 can be increased, and the upstream side of the supply flow path 43 with respect to each of the cooling flow paths 45. Since the cooling medium having the same temperature can be introduced, the light emitting element 23 can be cooled with the cooling medium with high efficiency.
Therefore, according to the light emitting element light source unit 10, the plurality of light emitting elements 23 constituting the light emitting source can be cooled efficiently and with high uniformity, thereby reducing the emission intensity and the illuminance on the irradiated surface. The occurrence of unevenness can be suppressed.
Here, according to the light emitting element light source unit 10 shown in the figure, as is apparent from an experimental example to be described later, in all of the light emitting elements 23 bonded on the substrate 21, the junction portion (semiconductor bonding portion). ) Is 60 ° C. or lower and can be within a temperature range of ± 1 ° C.

  In the light emitting element light source unit 10, the length of the path from the supply opening 43 </ b> A of the supply flow path 43 to the discharge opening 44 </ b> A of the discharge flow path 44 through each of the plurality of cooling flow paths 45. Since the same amount of the cooling medium can be caused to flow into each of the plurality of cooling flow paths 45 connected in parallel by the supply flow path 43 and the discharge flow path 44, The cooling efficiency for each of the plurality of light emitting elements 23 by the medium can be further uniformed.

As shown in FIG. 7, the light emitting element light source unit 10 is suitably used as a fixing light irradiator in a photocurable ink jet printer apparatus.
In the photocurable ink jet printer apparatus, for example, a fixing light irradiator composed of a light emitting element light source unit 10 is integrally disposed adjacent to an ink jet head 51 that ejects photocurable ink, When the photocurable ink is ejected from the head 51 to the print medium 52 such as paper, the print medium 52 to which the ejected ink is attached is irradiated with light, whereby the print medium 52 is exposed to the ink. Is fixed or assumed.
In the process of fixing or assuming the ink on the print medium 52 by such a photo-curing type ink jet printer apparatus, one or both of the head 51 and the print medium 52 are moved, whereby the head 51 and the print medium 52 are moved. As shown by the arrows in FIG.

  According to such a photo-curable inkjet printer apparatus, light having a sufficient light emission intensity can be emitted from the fixing light irradiator to the print medium 52 to which the ink is adhered without uneven irradiation. The printed image obtained can be of good image quality.

In the light emitting element light source unit of this invention, it is not limited to said embodiment, A various change can be added.
For example, in a light emitting element light source unit, a light emitting element constituting a light emitting unit is directly arranged on the upper surface of a heat sink, and a wiring pattern is applied to the upper surface of the heat sink, that is, the heat sink has a function as a substrate. It may be of a different configuration.
In such a case, since the light emitting element is directly cooled by the heat sink, the light emitting element can be cooled more effectively.

In addition, the heat sink may have a configuration in which a heat transfer suppression unit including a slit or the like is provided between the supply channel and the discharge channel.
In such a case, the heat transfer suppression unit can suppress the transfer of heat between the supply flow path and the discharge flow path, so that the heat reception from the cooling medium flowing in the discharge flow path. As a result, it is possible to suppress the temperature gradient of the cooling medium from increasing in the supply flow path and the occurrence of a temperature gradient, so that the light emitting element can be cooled more efficiently.

Further, in the heat sink, the heat sink body has different materials in the upper surface side portion where the cooling flow path is provided and the lower surface side portion where the supply flow path and the discharge flow path are provided, and the lower surface side portion is the upper surface side portion. It may be made of a material having a lower thermal conductivity than
In such a case, since it is possible to suppress the transfer of heat between the supply flow path and the discharge flow path by making the material of the lower surface side portion low in thermal conductivity, The temperature of the cooling medium rises in the supply flow path due to heat received from the cooling medium flowing in the discharge flow path, and a temperature gradient can be suppressed, so that the light emitting element can be cooled more efficiently. Can do.
Even in such a case, the light-emitting element can be cooled more efficiently by providing a heat transfer suppression unit including a slit or the like between the supply channel and the discharge channel.

Further, as shown in FIG. 8, the light emitting element light source unit includes a plurality of cooling medium circulation channels in the heat sink 30 according to the number or arrangement state of the light emitting elements 23 constituting the light emitting source (in the example of FIG. 8). A plurality of cooling channel parallel connection channels 40 in which three cooling channels 45 are connected in parallel by one supply channel 43 and one discharge channel 44 (three in the example of FIG. 8). However, a configuration in which the common supply channel 55 and the common discharge channel 56 are connected in parallel may be used. The common supply channel 55 is connected to a supply path 41 that communicates with the supply unit, and the common discharge channel 56 is connected to a discharge channel 42 that communicates with the discharge unit.
According to the light emitting element light source unit having such a configuration, a larger number of light emitting elements 23 can be used as light emitting sources.
Even in such a case, it is possible to cool the light emitting element more efficiently by providing a heat transfer suppressing portion including the slit 37 between the supply flow path 43 and the discharge flow path 44.
In the example of this figure, a slit 37 having a width of 5 mm is formed between the supply flow path 43 and the discharge flow path 44 between the cooling flow path parallel connection flow paths 40 adjacent to each other.

  Examples of experiments conducted for confirming the effects of the present invention will be described below.

[Experimental Example 1]
A light-emitting element light source unit (hereinafter, also referred to as “light-emitting element light source unit (1)”) having the configuration of FIG. 1 was manufactured.
The substrate constituting this light-emitting element light source unit (1) has 48 light-emitting portions each made up of one LED element having a peak emission wavelength of 365 nm arranged in two rows at a pitch of 4.6 mm, 16 mm wide, vertically It is made of aluminum nitride having a thickness of 113 mm and a thickness of 0.6 mm.
The heat sink includes a heat sink body made of copper, the cross-sectional shape is a circular shape (cross-sectional area of 12 mm ² ), the cross-sectional shape is a rectangular shape with a width of 2.5 mm and a height of 5 mm,
An inflow channel having a circular cross-sectional shape (cross-sectional area of 3 mm ² ), a rectangular cooling channel having a cross-sectional shape of 3 mm in width and a height of 1 mm, an outflow channel having a circular cross-sectional shape (cross-sectional area of 3 mm ² ), The discharge channel has a rectangular shape with a cross-sectional shape of 2.5 mm in width and a height of 5 mm, and a discharge channel with a circular cross-section (cross-sectional area of 12 mm ² ), and is discharged from the supply opening through the cooling channel. A flow path having a length of three paths of 164 mm up to the service opening is formed.

About the produced light emitting element light source unit (1), the cooling medium which consists of cooling water with a temperature of 25 degreeC with respect to the inside of a heat sink is supplied by various conditions (total amount of cooling water), and circulation of the cooling medium formed in the heat sink The pressure loss in the flow path was confirmed. The results are shown by curve (A) in FIG.
In addition, for each of the three paths from the supply opening to the discharge opening through the cooling channel, the condition of the cooling medium to the heat sink is 1 liter / min (the cooling medium inflow condition in each cooling channel) Was 14.5 kPa when the pressure loss was confirmed at a rate of 1/3 liter / min.

  In addition, for the light emitting element light source unit (1), a cooling medium is supplied to the heat sink at a condition of 1 liter / min (the cooling medium inflow condition in each cooling channel is 1/3 liter / min). The rising temperature in the supply channel was confirmed from the temperature difference between the temperature of the cooling medium in the supply opening and the temperature of the cooling medium at the inlet of the cooling channel located on the most downstream side of the supply channel. It was 5 ° C. Further, when the temperature of the junction (semiconductor junction) in each light emitting element emitting light under the condition of a calorific value of 170 W was confirmed, it was 60 ° C. or less and the temperature range was within ± 1 ° C. It was.

[Comparative Experiment Example 1]
As shown in FIG. 9, a light emitting element light source unit having a configuration in which cooling channels 45 are connected in series (hereinafter, also referred to as “comparative light emitting element light source unit (1)”) was manufactured.
In this comparative light-emitting element light source unit (1), the three cooling channels 45 in the circulation channel of the cooling medium in the heat sink 60 have a rectangular channel 61 (width 2.5, height 5 mm). ) Have the same configuration as the light emitting element light source unit (1) except that they are connected in series.

  About the light emitting element light source unit (1) for a comparison, the pressure loss in the circulation channel of the cooling medium formed in the heat sink was confirmed in the same manner as in Experimental Example 1. The result is shown by the curve (B) in FIG.

From the result of FIG. 10, in the light emitting element light source unit (1), the pressure loss increases slightly as the supply amount of the cooling medium increases, but the increase rate is higher than that of the comparative light emitting element light source unit (1). It is clear that it is extremely small.
Specifically, for example, when the cooling medium is supplied under the condition of 1 liter / min, the pressure loss of the path related to one cooling channel in the light emitting element light source unit (1) is 0.0145 MPa. On the other hand, since the pressure loss in the comparative light emitting element light source unit (1) is 1.2 MPa, the comparative light emitting element light source unit (1) has a pressure of 80 times or more that of the light emitting element light source unit (1). It will be appreciated that a cooling medium needs to be supplied.

  From the result of the above experimental example, according to the light emitting element light source unit (1) according to the present invention, the total flow path of the flow path for circulating the cooling medium corresponding to the light emitting part without causing a large pressure loss. It has been confirmed that the length can be increased, and that the plurality of light emitting elements constituting the light emitting source can be cooled efficiently and with high uniformity.

DESCRIPTION OF SYMBOLS 10 Light emitting element light source unit 11 Light source module 13 Cover member 13A Area | region 17 Light irradiation window 18 Power supply connector 19 Screw 21 Board | substrate 22 Light emitting part 23 Light emitting element 24 Connector 30 Heat sink 31 Heat sink main body 32 Upper surface side part 33 Lower surface side part 34 Supply part 35 Discharge unit 37 Slit 40 Cooling flow path parallel connection flow path 41 Supply path 42 Discharge path 43 Supply flow path 43A Supply opening 44 Discharge flow path 44A Discharge openings 45, 45A, 45B, 45C Cooling flow path 46 Inlet 47 Outlet 48 Inflow path 49 Outflow path 51 Head 52 Print medium 55 Common supply flow path 56 Common discharge flow path 60 Heat sink 61 Flow path 65 Flow path 66 LED element 67 Heat sink

Claims (6)

In the light emitting element light source unit including a heat sink in which a plurality of light emitting units each including one or more light emitting elements are positioned on the upper surface,
The heat sink includes a cooling channel for circulating a cooling medium corresponding to one or a plurality of light emitting units on the upper surface side level, and an inlet and an outlet of the cooling medium in the cooling channel are respectively A light-emitting element light source unit, which is connected to a cooling medium supply channel and a cooling medium discharge channel formed at a lower surface side level than the cooling channel.   The heat sink is provided with a plurality of cooling channels, and the inlet and the outlet of each of the plurality of cooling channels are connected to a common supply channel and a common discharge channel. The light emitting element light source unit according to claim 1.   The length of the path from the most upstream position of the supply flow path to the most downstream position of the discharge flow path via the cooling flow path is the same for each of the cooling flow paths. The light emitting element light source unit of description.   The light-emitting element light source unit according to any one of claims 1 to 3, wherein the cooling channel is annular, and an inlet and an outlet of the cooling medium are provided at symmetrical positions.   The light emitting element light source unit according to any one of claims 1 to 3, wherein all of the light emitting elements constituting the plurality of light emitting units are arranged in a region immediately above the cooling flow path.   The light-emitting element light source unit according to claim 1, wherein the light-emitting element light source unit is used as a fixing light irradiator of a photo-curable ink jet printer apparatus.