Light irradiation testing device

Abstract

To properly cool a LED light source in a light irradiation test device using the LED light source, and to keep illuminance therein.SOLUTION: A light irradiation test device 1 comprises: a sample stage 6 on which a sample 7 is loaded; at least one LED light source 8 that has a light emission surface 8a facing the sample stage 6, and irradiates the sample 7 with light from the light emission surface 8a; a thermal conductor 9 that is arranged so as to contact with a rear surface 8b of the LED light source 8; a cooling pipe 10 that is arranged across at least one part of the thermal conductor 9 on a rear surface 8a side of the LED light source 8, in which a coolant 11 flows; and a ventilator 12 that ventilates cooling air 13 into the LED light source 8. The cooling air 13 ventilated from the ventilator 12 is configured to be guided to the light emission surface 8a of the LED light source 8. A temperature of the cooling air 13 is equal to or less than that of the coolant 11.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to a light irradiation test apparatus used for a light resistance test or the like.

Background Art

[0002] The light resistance test is a test for evaluating the degree of deterioration or the like of a sample by irradiating the sample with light from a light source. In such a light resistance test, a light irradiation test apparatus that irradiates light on a sample under various environments is used. As the light source of a conventional light irradiation test apparatus, an incandescent bulb, an arc lamp, or the like has been used (see Patent Documents 1 and 2).

[0003] In recent years, lighting devices using LED light sources have been becoming popular. Since the materials constituting a lighting device using an LED light source need to have resistance to the light irradiated from the LED light source, a light resistance test must be performed to select a material having excellent light resistance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0008] To achieve the above objective, the light irradiation test apparatus according to the present invention comprises a sample stage on which a sample is placed, at least one LED light source having a light-emitting surface facing the sample stage and irradiating the sample with light from the light-emitting surface, a heat conductor arranged to be in contact with the back surface of the LED light source opposite to the light-emitting surface, a cooling pipe arranged on the back side of the LED light source with at least a portion of the heat conductor in between and through which a cooling liquid flows, and a blower that blows cooling gas to the LED light source, wherein the cooling gas blown from the blower is guided to the light-emitting surface of the LED light source.

[0009] According to the light irradiation test apparatus of the present invention, the back side of the LED light source can be strongly cooled by a cooling liquid, while the light-emitting side of the LED light source can be gently cooled by a cooling gas. Therefore, by combining cooling with a cooling liquid and cooling with a cooling gas, the LED light source can be appropriately cooled without overcooling, allowing light irradiation tests to be performed while maintaining high illuminance.

[0010] Furthermore, in the light irradiation test apparatus according to the present invention, the air outlet of the blower may face the circumferential surface connecting the light-emitting surface and the back surface of the LED light source. In this case, the cooling gas blown from the blower can be guided from the circumferential surface side to the light-emitting surface side of the LED light source. In this case, if the edge of the air outlet on the sample stage side is located closer to the sample stage than the light-emitting surface of the LED light source, the cooling gas blown from the blower can be reliably guided to the light-emitting surface of the LED light source. Also, if the edge of the air outlet on the opposite side of the sample stage is located further away from the sample stage than the heat conductor, the back side of the LED light source can also be cooled by the cooling gas blown from the blower. In other words, the entire light source chamber in which the LED module having the LED light source, heat conductor and cooling tube is arranged can be cooled, thereby further improving the cooling efficiency of the LED light source.

[0011] Furthermore, in the light irradiation test apparatus according to the present invention, a light-transmitting partition member may be further arranged between the LED light source and the sample stage. In this case, the light source chamber where the LED module is placed and the test chamber where the sample stage is placed are separated by the partition member, thereby further improving the cooling efficiency of the LED light source by the cooling tube and blower. [Effects of the Invention]

[0012] According to the present invention, in a light irradiation test apparatus using an LED light source, the LED light source can be appropriately cooled to maintain illuminance. [Brief explanation of the drawing]

[0013] [Figure 1] This is a cross-sectional view of the light irradiation test apparatus according to Embodiment 1. [Figure 2] This is a cross-sectional view of a light irradiation test apparatus according to a modified example of Embodiment 1. [Figure 3] This is a cross-sectional view of the light irradiation test apparatus according to Embodiment 2. [Figure 4] This is a cross-sectional view of the light irradiation test apparatus according to Embodiment 3. [Modes for carrying out the invention]

[0014] (Embodiment 1) The light irradiation test apparatus 1 according to Embodiment 1 will be described below with reference to Figure 1.

[0015] As shown in Figure 1, the interior of the housing 2 of the light irradiation test apparatus 1 is divided into a test chamber 4 and a light source chamber 5 by a partition member 3 that transmits the irradiated light, for example. The housing 2 may be made of stainless steel, for example. The partition member 3 may be made of heat-resistant glass, for example. In this embodiment, the test chamber 4 is located on the lower side and the light source chamber 5 is located on the upper side in the vertical direction.

[0016] A sample stand 6 is placed inside the test chamber 4, and during the light irradiation test, the sample 7 to be tested is placed on the sample stand 6. The sample stand 6 is preferably made of a material with multiple through holes, such as wire mesh or expanded metal. Such a material can suppress heat accumulation in the sample stand 6, thereby suppressing heat conduction from the sample stand 6 to the placed sample 7, and thus minimizing the temperature influence on the sample 7. The sample stand 6 may also be provided with means for fixing the sample 7, such as a suction means. The sample stand 6 may be held in place by a holding member (not shown) provided at the bottom of the test chamber 4, for example. Alternatively, hooks for adjusting the position of the sample stand 6 may be provided on both opposing inner wall surfaces of the test chamber 4, and the sample stand 6 may be supported on these hooks.

[0017] Inside the light source chamber 5, at least one LED light source 8 is arranged to irradiate the sample 7 with light through the partition member 3. The LED light source 8 is positioned so that its light-emitting surface 8a and the sample stage 6 face each other. In this embodiment, the light-emitting surface 8a of the LED light source 8 is set to be parallel to the horizontal plane.

[0018] As the LED light source 8, for example, LED chips such as COB (chip-on-board) or SMD (surface-mount device) may be used, but it is preferable to use COB for light irradiation tests that require particularly high illumination. There may be only one LED light source 8, but multiple LED light sources 8 may be used to perform light irradiation tests with higher illumination. In the latter case, multiple LED light sources 8 may be arranged in a matrix. The wavelength of the light emitted from the LED light source 8 should be appropriately selected according to the environment in which the sample 7 is used. For example, if indoor use is assumed, an LED light source 8 that emits light in the visible light range (wavelength 380nm to 780nm) can be selected.

[0019] A heat conductor 9 is arranged so as to contact the back surface 8b (the surface opposite to the light emitting surface 8a) of the LED light source 8. The constituent material of the heat conductor 9 is not particularly limited as long as it has a high thermal conductivity, but for example, aluminum may be used in terms of cooling efficiency. The heat conductor 9 is held by, for example, a holding member (not shown) provided on the side wall portion or the ceiling portion of the light source chamber 5. The LED light source 8 is attached to the heat conductor 9.

[0020] A cooling pipe 10 is arranged on the back surface 8b side of the LED light source 8 while sandwiching at least a part of the heat conductor 9. A coolant 11 such as cooling water flows through the cooling pipe 10. The cooling pipe 10 is connected in a circulating manner to a refrigerator (not shown) arranged outside the housing 2. In the present embodiment, as an example, the cooling pipe 10 is embedded in the heat conductor 9 along the arrangement of the LED light sources 8. The temperature of the coolant 11 can be adjusted by the refrigerator used, but it may be set to about 28 to 32°C, for example.

[0021] A first air outlet 12a of a first blower 12 such as a blower fan is provided on the side wall portion of the light source chamber 5. That is, in the present embodiment, the first air outlet 12a faces the peripheral surface (the surface connecting the light emitting surface 8a and the back surface 8b) of the LED light source 8. The main body portion (not shown) of the first blower 12 is arranged outside the housing 2, and an air duct extends from the main body portion to the first air outlet 12a. An exhaust port (not shown) is provided on the side wall portion or the ceiling portion of the light source chamber 5.

[0022] The first blower 12 blows a cooling gas 13 such as cooling air to the LED light source 8. The first blower 12 may have a temperature adjustment function. The temperature of the cooling gas 13 can be adjusted by the first blower 12 used, but it may be set to about 25 to 35°C, for example.

[0023] In this embodiment, the light irradiation test apparatus 1 is configured such that the cooling gas 13 blown from the first blower 12 is guided to the light-emitting surface 8a of the LED light source 8. Specifically, the edge of the first air outlet 12a of the first blower 12 on the test chamber 4 side (i.e., the sample stage 6 side) is located closer to the sample stage 6 than the light-emitting surface 8a of the LED light source 8. For example, the edge of the first air outlet 12a on the sample stage 6 side is located closer to the sample stage 6 by a distance d in the vertical direction compared to the light-emitting surface 8a of the LED light source 8. Furthermore, the edge of the first air outlet 12a of the first blower 12 on the opposite side of the test chamber 4 (i.e., the opposite side of the sample stage 6) is located on the opposite side of the sample stage 6 than the heat conductor 9.

[0024] A second air outlet 14a of a second blower 14, such as a blower fan, is provided on the side wall of the test chamber 4 to maintain a predetermined temperature inside the test chamber 4. The main body (not shown) of the second blower 14 is located outside the housing 2, and a blower pipe extends from the main body to the second air outlet 14a. An exhaust port (not shown) is provided on the side wall or bottom of the test chamber 4. The second blower 14 blows a gas 15, such as air, onto the sample 7. The second blower 14 may have a temperature control function. The temperature of the gas 15 can be adjusted by the second blower 14 used, but it may be set to approximately 60-120°C when the LED light source 8 is lit.

[0025] Although not shown in the illustration, the light irradiation test apparatus 1 may have an operating section (e.g., a touch panel) on the outer wall surface of the housing 2 for operating the LED light source 8, blowers 12, 14, etc.

[0026] As described above, the light irradiation test apparatus 1 of this embodiment allows for strong cooling of the back surface 8b of the LED light source 8 by the coolant 11, while the light-emitting surface 8a of the LED light source 8 is gently cooled by the cooling gas 13. Therefore, by combining cooling with the coolant 11 and cooling with the cooling gas 13, the LED light source 8 can be appropriately cooled without overcooling, allowing for light irradiation testing while maintaining high illuminance. Furthermore, it prevents the LED light source 8 from overheating and failing. In particular, when the illuminance of the LED light source 8 is around 3 million lux or higher, the LED light source 8 accumulates heat and becomes hot, requiring cooling with the coolant. In this case, the aforementioned effects of the light irradiation test apparatus 1 of this embodiment are significant.

[0027] Furthermore, in the light irradiation test apparatus 1 of this embodiment, the air outlet 12a of the blower 12 faces the circumferential surface connecting the light-emitting surface 8a and the back surface 8b of the LED light source 8, so that the cooling gas 13 blown from the blower 12 can be guided from the circumferential surface side to the light-emitting surface 8a side of the LED light source 8. In this case, the edge of the air outlet 12a on the sample stage 6 side is located closer to the sample stage 6 than the light-emitting surface 8a of the LED light source 8, so that the cooling gas 13 blown from the blower 12 can be reliably guided to the light-emitting surface 8a of the LED light source 8. Also, since the edge of the air outlet 12a opposite to the sample stage 6 is located on the opposite side of the sample stage 6 than the heat conductor 9, the back surface 8b side of the LED light source 8 can also be cooled by the cooling gas 13 blown from the blower 12. In other words, the entire light source chamber 5 in which the LED module having the LED light source 8, heat conductor 9, and cooling tube 10 is arranged can be cooled, so that the cooling efficiency of the LED light source 8 can be further improved.

[0028] Furthermore, in the light irradiation test apparatus 1 of this embodiment, a partition member 3 that transmits light irradiated from the LED light source 8 is placed between the light source chamber 5 and the test chamber 4 (i.e., between the LED light source 8 and the sample stage 6), thereby further improving the cooling efficiency of the LED light source 8 by the cooling pipe 10 and the blower 12.

[0029] In this embodiment, the temperature of the cooling gas 13 may be set to be equal to or lower than the temperature of the coolant 11. Doing so makes it less likely for condensation to occur inside the light source chamber 5, thereby suppressing the occurrence of failures of the LED light source 8 and other components. For example, the temperatures of the cooling gas 13 and the coolant 11 may both be set to 30°C. Furthermore, in order to further suppress the occurrence of condensation inside the light source chamber 5, a dehumidifying means, such as a desiccant, may be provided inside the light source chamber 5.

[0030] (Modified version of Embodiment 1) The following describes a modified light irradiation test apparatus 1 according to Embodiment 1, with reference to Figure 2. In Figure 2, the same reference numerals are used for the same components as in Embodiment 1 shown in Figure 1.

[0031] The difference between this modified light irradiation test apparatus 1 and Embodiment 1 is that, as shown in Figure 2, the test chamber 4 and the light source chamber 5 are arranged horizontally. Here, the light-emitting surface 8a of the LED light source 8 is set to be parallel to the vertical plane. That is, the LED light source 8 emits light in the horizontal direction.

[0032] The same effects as in Embodiment 1 can be obtained with the modified light irradiation test apparatus 1 described above.

[0033] (Embodiment 2) The light irradiation test apparatus 1 according to Embodiment 2 will be described below with reference to Figure 3. In Figure 3, the same reference numerals are used for the same components as in Embodiment 1 shown in Figure 1.

[0034] The difference between the light irradiation test apparatus 1 of this embodiment and Embodiment 1 is that, as shown in Figure 3, the edge of the first air outlet 12a of the first blower 12 on the test chamber 4 side (i.e., the sample stage 6 side) is located on the opposite side of the sample stage 6 from the light-emitting surface 8a of the LED light source 8, while a guide member 21 is provided between the LED module having the LED light source 8, heat conductor 9, and cooling tube 10 and the first air outlet 12a to guide the cooling gas 13 blown from the first blower 12 to the light-emitting surface 8a of the LED light source 8.

[0035] The same effects as in Embodiment 1 can be obtained with the light irradiation test apparatus 1 of this embodiment described above.

[0036] In this embodiment, instead of installing the guide member 21, the air pipe of the first blower 12 may be extended into the light source chamber 5, and the first air outlet 12a may be positioned near the light-emitting surface 8a of the LED light source 8.

[0037] (Embodiment 3) The light irradiation test apparatus 1 according to Embodiment 3 will be described below with reference to Figure 4. In Figure 4, the same reference numerals are used for the same components as in Embodiment 1 shown in Figure 1.

[0038] The difference between the light irradiation test apparatus 1 of this embodiment and Embodiment 1 is that, as shown in Figure 4, the first air outlet 12a of the first blower 12 is provided on the ceiling of the light source chamber 5, while a guide member 22 is provided between the LED module having an LED light source 8, a heat conductor 9, and a cooling pipe 10 and the side wall of the light source chamber 5 to guide the cooling gas 13 blown from the first blower 12 to the light-emitting surface 8a of the LED light source 8. That is, the cooling gas 13 blown out from the first air outlet 12a on the ceiling of the light source chamber 5 travels along the side wall of the light source chamber 5 along the surface of the heat conductor 9 opposite to the LED light source 8, bypasses the LED module by the guide member 22, and reaches the light-emitting surface 8a of the LED light source 8.

[0039] The same effects as in Embodiment 1 can be obtained with the light irradiation test apparatus 1 of this embodiment described above.

[0040] In this embodiment, the air duct of the first blower 12 may penetrate the ceiling of the light source chamber 5 and terminate at the first air outlet 12a, or it may penetrate the side wall of the light source chamber 5, extend along the ceiling of the light source chamber 5 to near the center of the ceiling, and terminate at the first air outlet 12a. In other words, in this embodiment and other embodiments (including modified versions), the path of the air duct from the main body of the first blower 12 to the first air outlet 12a, and the position where the air duct penetrates the housing 2 are not particularly limited.

[0041] Furthermore, a lightfastness test method is provided for testing the lightfastness of a sample 7 using the light irradiation test apparatus 1 according to each of the embodiments (including modified examples) described above. According to this lightfastness test method, since it is possible to irradiate the sample with high-intensity light from the LED light source 8, lightfastness can be evaluated in a short period of time. Moreover, if the wavelength of the light irradiated from the LED light source 8 is in the visible light region (wavelength 380nm to 780nm), the lightfastness of the sample 7 for indoor use can be appropriately evaluated.

[0042] While embodiments and modifications have been described above, it will be understood that a variety of changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, these embodiments and modifications may be combined or substituted as appropriate, as long as they do not impair the functions of the subject matter of this disclosure. Moreover, the terms “first,” “second,” etc., described above are used to distinguish the phrases to which these terms are attached, and do not limit the number or order of such phrases. [Explanation of Symbols]

[0043] 1. Light irradiation test apparatus 1 2 Housing 3. Partition members 4. Examination Room 5 Light source room 6. Sample stage 7 samples 8 LED light sources 8a Light-emitting surface 8b Back 9. Thermal conductors 10 Cooling pipe 11 Coolant 12 1st blower 12a First air outlet 13 Cooling gas 14 2nd blower 14a Second air outlet 15 Gases 21 Guide member 22 Guide member

Claims

1. A sample stand on which the sample is placed, At least one LED light source having a light-emitting surface facing the sample stage, which irradiates the sample with light from the light-emitting surface, A heat conductor is arranged so as to be in contact with the back surface opposite to the light-emitting surface of the LED light source, A cooling pipe is provided on the back side of the LED light source, with at least a portion of the heat conductor sandwiched between them, through which a cooling liquid flows; The LED light source is provided with a fan that blows cooling gas onto it. The cooling gas blown from the blower is configured to be guided to the light-emitting surface of the LED light source, A light irradiation test apparatus in which the temperature of the cooling gas is less than or equal to the temperature of the cooling liquid at the inlet of the cooling tube.

2. The air outlet of the blower is provided on the side wall of the light source chamber where the LED light source is located and is directly connected to the main body of the blower. The light irradiation test apparatus according to claim 1, wherein the cooling gas is blown directly from the air outlet to the LED light source.

3. The light irradiation test apparatus according to claim 1, wherein a guide member for guiding the cooling gas to the light-emitting surface of the LED light source is provided inside the light source chamber where the LED light source is arranged.

4. The light irradiation test apparatus according to any one of claims 1 to 3, wherein the temperature of the cooling gas used to cool the LED light source is 25 to 35°C.

5. The aforementioned LED light source is a chip-on-board LED chip, The light irradiation test apparatus according to any one of claims 1 to 4, wherein the illuminance of the LED light source is 3 million lux or more.

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