LED light source device

An LED light source device capable of making the amount of light of an emitting region a predetermined amount of light or more and uniformizing the amount of light is provided. The LED light source device 1 includes an ultraviolet LED array 3 including an LED juxtaposition region R in which LEDs 10 that emit ultraviolet light toward the front are juxtaposed, and a light transmitting member 4 provided on the front side of the LED juxtaposition region R of the ultraviolet LED array 3 so as to be opposed thereto, showing a rectangular parallelepiped outer shape, and formed of a material containing quartz. At a front surface 10a of the LED 10, an emitting surface S surrounded by a marginal portion 11 of a predetermined width H and for emitting the ultraviolet light is provided. Here, when viewed from the front, an end of the light transmitting member 4 is located between inside by ½ of the predetermined width H and outside by ½ of the predetermined width H with respect to an end of the LED juxtaposition region R of the ultraviolet LED array 3.

TECHNICAL FIELD

The present invention relates to an LED light source device that emits ultraviolet light.

BACKGROUND ART

As a conventional LED light source device, there has been known one described in, for example, the following patent document 1. In such an LED light source device, a translucent member made of acrylic is disposed on a front side of an LED array for which LEDs that emit visible light forward are juxtaposed, and a space between the LED array and translucent member is sealed by a transparent resin made of silicone. Then, visible light from the LEDs is emitted via the transparent resin and translucent member.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

Here, in such an LED light source device as described above, for example, when ultraviolet light is emitted to perform a process using light energy of the ultraviolet light, its processing ability greatly depends on the amount of light, and thus it is particularly demanded to make the amount of light of an emitting region a predetermined amount of light or more and uniformize the amount of light. However, in such an LED light source device as described above, the amount of light easily decreases at end portions of the emitting region, and the distribution of the amount of light easily shows a so-called fat-tailed state, and thus it is difficult to make the amount of light of the emitting region a predetermined amount of light or more and uniformize the amount of light.

Therefore, it is an object of the present invention to provide an LED light source device capable of making the amount of light of the emitting region a predetermined amount of light or more and uniformizing the amount of light.

Solution to Problem

In order to achieve the above-described object, an LED light source device according to the present invention includes an ultraviolet LED array including an LED juxtaposition region in which LEDs that emit ultraviolet light toward the front are juxtaposed, and a light transmitting member provided on the front side of the LED juxtaposition region of the ultraviolet LED array so as to be opposed thereto, showing a rectangular parallelepiped outer shape, and formed of a material containing quartz, in which at a front surface of the LEDs, an emitting surface surrounded by a marginal portion of a predetermined width and for emitting the ultraviolet light is provided, and when viewed from the front, an end of the light transmitting member is located between inside by ½ of the predetermined width and outside by ½ of the predetermined width with respect to an end of the LED juxtaposition region of the ultraviolet LED array.

In this LED light source device, because ultraviolet light emitted from the LEDs repeats total reflection inside the light transmitting member to be output forward, the peak amount of light in the output ultraviolet light (hereinafter, referred to as “output light”) can be increased. Here, because the light transmitting member shows a rectangular parallelepiped outer shape, ultraviolet light emitted from the LEDs can be reliably led to the light transmitting member, and a decrease (loss) in the amount of output light can be suppressed. Further, in addition thereto, when viewed from the front, because the ends of the light transmitting member are located between inside by ½ of the predetermined width and outside by ½ of the predetermined width with respect to the ends of the LED juxtaposition region of the ultraviolet LED array, respectively, the amount of light of the emitting region can be made a predetermined amount of light or more and uniformized. This is because of the following: as shown in, for example,FIG. 14, when the ends of the light transmitting member are too far apart inside from the ends of the LED juxtaposition region, respectively (broken line in the figure), there is provided a distribution of the amount of light gathering toward the center of the emitting region, so that the peak amount of light is increased, but the amount of light at end portions of the emitting region is low; moreover, when the ends of the light transmitting member are too far apart outside from the ends of the LED juxtaposition region, respectively (dotted line in the figure), the distribution of the amount of light shows a so-called fat-tailed state, and the peak amount of light decreases; and on the other hand, when the ends of the light transmitting member are located in a range of being inside by ½ of the predetermined width to outside by ½ thereof with respect to the ends of the LED juxtaposition region, respectively, (solid line in the figure), it becomes possible to sufficiently secure the peak amount of light while increasing the degree of rising and falling in the distribution of the amount of light.

Moreover, it is preferable that the light transmitting member is in contact with a front surface of the LEDs. In this case, ultraviolet light emitted from the LEDs can be more reliably led to the light transmitting member, and it becomes possible to suppress a decrease in the amount of light in the emitting region.

Moreover, it is preferable that the ultraviolet LED array includes a plurality of LED units each including a substrate and the LEDs juxtaposed so as to be adjacent to each other on a front surface side of the substrate, and the LED units are juxtaposed so that the LEDs are adjacent. In this case, the LEDs can be easily provided in a dense arrangement, and it becomes possible to obtain a large amount of light uniformly in the emitting region.

At this time, it is preferable that the LEDs show a rectangular parallelepiped outer shape, and are disposed on the substrate so that a side surface thereof is located on the same plane as a side surface of the substrate or disposed on the substrate so that a side surface thereof projects to the outside further than a side surface of the substrate. In this case, the LEDs between the juxtaposed LED units are also provided in a more dense arrangement.

Moreover, it is preferable to include a metal plate provided on a rear surface side of the substrate, and thermally connected with the LEDs via a through-hole formed in the substrate, and a heat sink thermally connected with the metal plate. In this case, the heat dissipation performance of the LEDs can be improved, and the operation stability of the LEDs can be improved.

Moreover, it is preferable that the light transmitting member is fixed by a pair of opposing side surfaces thereof being sandwiched by pressing members via interposing members. In this case, a situation such that ultraviolet light causes insufficient fixation of the light transmitting member can be prevented, and it becomes possible to stably fix the light transmitting member.

At this time, it is preferable that the interposing member is formed of a material containing a fluororesin. In this case, the ultraviolet resistance property and heat resistance property can be improved with regard to fixation of the light transmitting member.

Moreover, it is preferable that the pressing member has a screw mechanism. In this case, it becomes possible to easily fine adjust the fixing position of the light transmitting member.

Moreover, it is preferable to include a case for housing the ultraviolet LED array and the light transmitting member, and that in a front cover of the case, a pair of wall portions extending in a long side direction of the light transmitting member are formed, and the light transmitting member is fixed to the front cover by being sandwiched by the pair of wall portions via a resin member. In this case, it becomes possible to easily perform positioning of the light transmitting member for fixing the light transmitting member.

At this time, it is preferable that the resin member is an O-ring provided so as to wind around side surfaces of the light transmitting member. In this case, the light transmitting member can be easily fixed.

Moreover, it is preferable that the light transmitting member is fixed by adhesion with respect to the ultraviolet LED array. In this case, it becomes possible to stably fix the light transmitting member.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the amount of light of the emitting region can be made a predetermined amount of light or more and uniformized.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. The same or corresponding components are denoted with the same reference signs in the figures, and overlapping description will be omitted. It is noted that terms “upper,” “up,” “lower,” “down,” “left,” and “right” are used for descriptive purposes based on the states shown in the drawings.

FIG. 1is a front perspective view showing an LED light source device according to an embodiment of the present invention, andFIG. 2is a front perspective view showing a state without a front cover of the LED light source device ofFIG. 1. As shown inFIGS. 1 and 2, the LED light source device1of the present embodiment includes, inside a case2having a rectangular parallelepiped outer shape that forms its enclosure, an ultraviolet LED array3, a light transmitting member4, and a heat sink5(refer toFIG. 9). The LED light source device1performs, for example, resin curing or ink drying by irradiation with ultraviolet light (referred to also as ultraviolet rays or UV light) as LED light through an opening O formed in a front cover2a.

In the ultraviolet LED array3, a plurality of LEDs (Light-Emitting Diodes)10that emit ultraviolet light toward the front are juxtaposed in a matrix to form an LED juxtaposition region R. In the ultraviolet LED array3here, the LED juxtaposition region R as a disposition area in which a plurality of LEDs10are disposed is formed by juxtaposing LED units20(refer toFIG. 5), for each of which a plurality of LEDs10are unitized, so as to be adjacent in the left and right direction. The LED juxtaposition region R is surrounded by an outermost margin of the ultraviolet LED array3(LEDs10) when viewed from the front (ultraviolet emitting side). The LED juxtaposition region R of the present embodiment consists of two upper and lower rows of 45 LEDs10from side to side (a total of 90 LEDs) juxtaposed, and is provided as a region having an oblong shape whose short side direction is the up and down direction and whose long side direction is the left and right direction in a front view.

FIG. 3is a schematic view showing a part of a section along a line ofFIG. 2,FIG. 4is a schematic view showing a part of a section along a line IV-IV ofFIG. 2, andFIG. 5is a front perspective view showing an LED unit of the LED light source device ofFIG. 1. As shown inFIGS. 3 to 5, the LED unit20includes a substrate21, LEDs10juxtaposed in a plural number on the side of a front surface21aof the substrate21, and a thermally conductive plate (metal plate)22fixed to the side of a rear surface (back surface)21bof the substrate21.

The LED10is an ultraviolet light emitting chip type light emitting element for which semiconductor crystals15are housed inside a housing X showing a rectangular parallelepiped outer shape and sealing is provided by a glass plate14, and emits a high output ultraviolet light. The LED10(housing X) has a square shape when viewed from a front surface10athereof from which ultraviolet light is emitted, and has, for example, widths of vertically 7 mm×horizontally 7 mm.

Specifically, in the LED10, a recess portion12having a circular section is formed in such a manner so as to be surrounded by a frame-shaped marginal portion11having a predetermined width H when viewed from the front. In other words, the LED10has a recess portion12formed inside a rectangular frame-shaped marginal portion11having a predetermined width H. Further, at a bottom surface12aof the recess portion12, a recess portion13having a circular section is formed.

At the side of the front surface10ainside of the recess portion12, a glass plate14that transmits ultraviolet light is provided so as to be the same plane as the front surface10a, and the inside of the LED10is thereby sealed. The glass plate14forms an emitting surface S to emit ultraviolet light. At a bottom surface13aof the recess portion13, semiconductor crystals15for producing ultraviolet light are fixed. Moreover, an inner side surface of the recess portion13is provided as a reflecting surface13bthat inclines so as to expand forward in order to reflect ultraviolet light toward the front.

Based on the above, the predetermined width H of the LED10in the present embodiment means the width of the frame11of the housing X that surrounds the glass plate14serving as the emitting surface S of the LED10. In other words, the predetermined width H corresponds to the length of a part where a straight line that is extended from the center of the recess portion12to the periphery of the LED juxtaposition region R intersects the marginal portion11of the LED10when viewed from the front. Here, the predetermined width H is provided as 2 mm. In the following, the predetermined width H is considered to be two times (that is,2α) a predetermined value α, and the predetermined value α is therefore provided as 1 mm.

FIG. 6is a rear perspective view showing an LED in the LED unit of the LED light source device ofFIG. 1. As shown inFIG. 6, at both end portions of a rear surface10b(surface on the opposite side to the front surface10a), a cathode terminal16aand an anode terminal16bthat extend in parallel are provided. Between the cathode terminal16aand the anode terminal16bin the rear surface10b, a metallic heat dissipating surface17showing a rectangular shape is provided as a surface to cool the LED10.

FIG. 7is a front view showing a substrate in the LED unit of the LED light source device ofFIG. 1. As shown inFIG. 7, the substrate21shows a rectangular plate shape whose two opposing sides have linear portions, and includes a plurality of through-holes24for bringing the LEDs10into contact with the thermally conductive plate22. The through-holes24are provided so as to correspond to the juxtaposed LEDs10, and here, extend in the up and down direction and are formed in four columns in the left and right direction. Moreover, the substrate21is formed with a pair of through-holes25through which screws31(refer toFIG. 2) to fix the LED unit20to the inside of the case2are inserted, respectively.

Moreover, at an upper portion of the substrate21, a power supply wiring portion26is provided. The power supply wiring portion26, which is a collection of electrical wiring patterns (not shown) provided on the substrate21and to be electrically connected to the LEDs10, provides an integrated power supply portion for the LEDs10. As shown inFIG. 9, the power supply wiring portion26is electrically connected by a wiring8with respect to a circuit element and the like of a substrate33fixed to an upper cover2c.

FIG. 8(a) is a front view showing a thermally conductive plate in the LED unit of the LED light source device ofFIG. 1, andFIG. 8(b) is a sectional view along a line VIII(b)-VIII(b) ofFIG. 8(a). As shown inFIGS. 8, one thermally conductive plate22is provided for each substrate21to function as a thermally conductive member that conducts heat of the multiple LEDs10to the heat sink5collectively, and is formed of, for example, a metallic material with a high thermal conductivity such as copper. At a front surface22aof the thermally conductive plate22, a plurality of projecting portions27extending in the up and down direction are formed as portions that enter into the through-holes24of the substrate21, and make contact with the heat dissipating surfaces17of the LEDs10, respectively. The projecting portions27project at least as thick as the substrate21. Moreover, in the thermally conductive plate22, a pair of through-holes35that communicate with the through-holes25of the substrate21, respectively, are formed. The thermally conductive plate22has such a size and shape so as to fit inside the rear surface21bof the substrate21.

As shown inFIG. 5, in the LED unit20including such LEDs10, substrate21, and thermally conductive plate22as in the above, a plurality of LEDs10are juxtaposed on each of the through-holes24,24,24,24in the front surface21aof the substrate21while the terminals16a,16bof the LEDs10and the power supply wiring portion26are electrically connected via electrical wiring patterns (not shown). Here, two rows and four columns of LEDs10with their mutual side surfaces made adjacent are disposed and fixed to the substrate21. Moreover, the LEDs10and the substrate21are disposed so that, at each of both side portions in the left and right direction being a juxtaposing direction of the LED units20, side surfaces10cof the LEDs10lie along a side surface21cof the substrate21and are adjacent thereto. In greater detail, the side surfaces10cof the LEDs10are located on the same plane as (become flush with) the side surface21cof the substrate21.

Simultaneously therewith, as shown inFIGS. 3 and 4, the projecting portions27of the thermally conductive plate22disposed so as to fit inside the rear surface21bof the substrate21with the substrate21sandwiched enter into the through-holes24, respectively, while the thermally conductive plate22is fixed by brazing to the heat dissipating surfaces17(refer toFIG. 6) of the rear surfaces10bof the LEDs10. Accordingly, the LEDs10, the substrate21, and the thermally conductive plate22are united, while the heat dissipating surfaces17(refer toFIG. 6) of the rear surfaces10bof the LEDs10are thermally connected to the thermally conductive plate22. Further, by juxtaposing the LED units20in the left and right direction inside the case2so that left and right side surfaces of the neighboring LED units20are adjacent to each other and, more preferably, without a gap therebetween, an ultraviolet LED array3in which the LEDs10are successively disposed in an adjacent manner is formed.

FIG. 9is a front perspective view showing a part of a state without a front cover and an upper cover of the LED light source device ofFIG. 1. As shown inFIG. 9, the heat sink5, which dissipates heat of the LEDs10, is formed of, for example, an aluminum material. The heat sink5, as shown inFIG. 4, includes a main body28having a fin structure where a plurality of metal plates are stacked in the left and right direction apart from each other and a plate-shaped joint portion29that fixes the main body28and joins the main body28to the thermally conductive plate22.

The heat sink5is disposed on a rear side of the LED unit20inside the case2. Simultaneously therewith, its joint portion29is brought into contact with the thermally conductive plate22of the LED unit20via a resin (grease) with a high thermal conductivity. Further, the heat sink5and the LED unit20are joined and fixed to each other by the screws31inserted though the through-holes25,35of the LED unit20. By thus bringing the joint portion29and the thermally conductive plate22into contact via the grease, heat dissipation performance can be improved through improvement in adhesion.

Referring back toFIG. 2, similar to the ultraviolet LED array3, the light transmitting member4shows a rectangular parallelepiped outer shape whose short side direction is the up and down direction and whose long side direction is the left and right direction and having a thickness smaller than the length in the short side direction, and is made of quartz. The light transmitting member4has a function as a lens or a mixing member, and repeatedly totally reflects inside ultraviolet light emitted from the LEDs10to increase the peak amount of ultraviolet light while uniformizing the amount of light. The light transmitting member4is subjected to mirror polishing at its outer surface. The thickness of the light transmitting member4is 3 mm to 20 mm, and more preferably, 4 mm to 12 mm, and in the present embodiment, provided as 5 mm.

The light transmitting member4, as shown inFIGS. 3 and 4, is provided on the front side of the LED juxtaposition region R of the ultraviolet LED array3so as to be opposed thereto. Specifically, the light transmitting member4is brought into contact at its rear surface4bwith the front surfaces10aof the LEDs10. Further, as shown in FIG.2, both end portions in the long side direction of the light transmitting member4are retained and fixed to the joint portion29of the heat sink5by end retaining portions41, and an intermediate portion in the long side direction is retained and fixed to the joint portion29by an intermediate retaining portion51via the LED unit20.

Here, as shown inFIG. 4, each of the one end and the other end in the long side direction (left and right direction) of the light transmitting member4is located inside by the predetermined value α with respect to each of the one end and the other end of the LED juxtaposition region R of the ultraviolet LED array3, when viewed from the front. That is, when viewed from the front, the ends in the long side direction of the light transmitting member4recede inside by ½ of the predetermined width H of the marginal portion11with respect to the ends of the LED juxtaposition region R of the ultraviolet LED array3, respectively. In other words, the LED juxtaposition region R projects by the predetermined value α (½ of the predetermined width H) with respect to the light transmitting member4in the long side direction.

Moreover, as shown inFIG. 3, one end and the other end in the short side direction (up and down direction) of the light transmitting member4are also located inside by the predetermined value α with respect to one end and the other end of the LED juxtaposition region R of the ultraviolet LED array3, respectively, when viewed from the front. That is, when viewed from the front, the ends in the short side direction of the light transmitting member4recede inside by ½ of the predetermined width H of the marginal portion11with respect to the ends of the LED juxtaposition region R of the ultraviolet LED array3, respectively. In other words, the LED juxtaposition region R projects by the predetermined value α with respect to the light transmitting member4in the short side direction.

Alternatively, in the present embodiment, as shown inFIG. 10, when viewed from the front, the ends in the long side direction of the light transmitting member4may be located outside by the predetermined value α (½ of the predetermined width H) with respect to the ends of the LED juxtaposition region R of the ultraviolet LED array3, respectively, in other words, the LED juxtaposition region R may recede inside by the predetermined value α with respect to the light transmitting member4in the long side direction. Moreover, as shown inFIG. 11, when viewed from the front, the ends in the short side direction of the light transmitting member4may be located outside by the predetermined value α (½ of the predetermined width H) with respect to the ends of the LED juxtaposition region R of the ultraviolet LED array3, respectively, in other words, the LED juxtaposition region R may recede inside by the predetermined value α with respect to the light transmitting member4in the short side direction.

Specifically, it suffices that the ends of the light transmitting member4of the present embodiment, in each of the long side direction and short side direction are located in a range of being inside by the predetermined value α (½ of the predetermined width H) to outside by the predetermined value α with respect to the ends of the LED juxtaposition region R, respectively, when viewed from the front. That is, it suffices to satisfy the condition of the following equation (1) representing a positional relationship when the light transmitting member4is disposed in terms of each of the long side direction and short side direction.
[End of LED juxtaposition region R−predetermined value α]≦[End of light transmitting member4]≦[End of LED juxtaposition region R+predetermined value α]  (1)

As an equation representing a size of the light transmitting member4such as to satisfy the above equation (1) in terms of each of the long side direction and short side direction, the following equation (2) can be mentioned. In connection to this, in the following equation (2), the width of the LED juxtaposition region R can be substituted by (LED width β×number n of LEDs) when the LEDs10are arrayed in close contact without a gap.
[Width of LED juxtaposition region R−2×predetermined value α]≦[Width of light transmitting member4]≦[Width of LED juxtaposition region R+2×predetermined value α]  (2)

As shown inFIG. 12, both end portions in the long side direction of the light transmitting member4are retained and fixed to the joint portion29by the end retaining portions41, respectively, as described above. The end retaining portion41includes a stay42provided at an end portion of the joint portion29, a pressing member43fixed to the stay42so as to be movable in the left and right direction, for pressing a left or right side surface4cof the light transmitting member4, and an interposing member44interposed between the pressing member43and the light transmitting member4.

The stay42shows an L-shape in section created by bending a plate, and includes a base portion42xthat extends in the left and right direction and a projecting portion42ythat continues from the inside in the left and right direction of the base portion42xand extends so as to project forward. The base portion42xis fixed to the end portion of the joint portion29of the heat sink5by a screw45. In the projecting portion42y, a through-hole46is provided, and at an inner peripheral surface of the through-hole46, a female screw47to be screwed with the pressing member43is formed.

The pressing member43uses a screw, at an outer peripheral surface of which a male screw48is formed. The interposing member44is provided as a plate member formed of a material containing a fluororesin. As the material of the interposing member44, Teflon (registered trademark) is used, for example.

In the end retaining portion41, by inserting the pressing member43through the through-hole46to screw the male screw48with the female screw47and moving by the screwing action the pressing member43to the inside in the left and right direction, the side surfaces4c,4c(refer toFIG. 2) of the light transmitting member4are sandwiched in the left and right direction via the interposing members44by means of tip portions43xof the pressing members43, respectively. Accordingly, the light transmitting member4is mechanically retained and fixed with respect to the joint portion29by a pressing force of screwing of the pressing members43via the interposing members44.

Moreover, as shown inFIG. 13, the intermediate portion in the long side direction of the light transmitting member4is retained and fixed to the joint portion29via the LED unit20by the intermediate retaining portion51, as described above. The intermediate retaining portion51includes main body blocks52,52provided as a pair so as to sandwich the light transmitting member4in the up and down direction, pressing members53fixed to the main body blocks52,52so as to be movable in the up and down direction, respectively, for pressing an upper or lower side surface4dof the light transmitting member4, and interposing members54each interposed between the pressing member53and the light transmitting member4.

The main body blocks52,52each show a rectangular parallelepiped outer shape whose long side direction is the left and right direction, and are respectively arranged so as to be opposed via the light transmitting member4. At both end portions in the left and right direction of the main body block52, through-holes52xthat communicate with the through-holes25,35of the LED unit20are provided. Moreover, in the main body block52, a through-hole52ythat extends in the up and down direction is provided, and at an inner peripheral surface of the through-hole52y, a female screw55to be screwed with the pressing member53is formed.

The pressing member53and the interposing member54are formed similarly to the pressing member43and the interposing member44, respectively. Specifically, the pressing member53uses a screw, at an outer peripheral surface of which a male screw56is formed. The interposing member54is a plate member formed of a material containing a fluororesin.

In the intermediate retaining portion51, the main body blocks52,52are disposed so that the through-holes52xand the through-holes25,35(refer toFIG. 5) of the LED unit20communicate with each other, and the screws31are inserted through the through-holes52x,25,35and screwed. Accordingly, the joint portion29of the heat sink5, the substrate33of the LED unit20, and the main body block52of the intermediate retaining portion51are fixed to each other.

In the fixed state, by inserting the pressing member53through the through-hole52yto screw the male screw56with the female screw55and moving by the screwing action the pressing member53to the inside in the up and down direction, the side surfaces4d,4dof the light transmitting member4are sandwiched in the up and down direction via the interposing members54by means of tip portions of the pressing members53, respectively. Accordingly, the light transmitting member4is further mechanically retained and fixed with respect to the joint portion29by a pressing force of screwing of the pressing members53via the interposing members54.

As shown inFIG. 9, a gap C is formed with the substrate33at a middle portion in the left and right direction of the main body block52of the intermediate retaining portion51. According to the gap C, interference between the intermediate retaining portion51and the power supply wiring portion26can be avoided, and it becomes possible to improve the heat dissipation performance of the LED unit20and, eventually, the heat dissipation performance of the LEDs10.

In connection to this, in the LED light source device1, a fan device (not shown) to send the air inside the case2out of the case2is disposed, as a cooling structure, behind the heat sink5. By the fan device, cooling air is led into the case2via a cooling vent K1(refer toFIG. 1) provided in the front cover2a, a cooling vent K2provided in a case side surface2d, and a cooling vent provided in a case lower surface2e. Then, the cooling air led inside flows rearward along the heat sink5to cool the heat sink5, and is led out of the case2from a rear surface2b(refer toFIG. 1) of the case2.

At this time, as shown inFIGS. 1 and 2, because the cooling vent K1is located above the power supply wiring portion26of the LED unit20in a state where the front cover2ais mounted, even when foreign matter such as emissions from an irradiation object enters inside through the cooling vent K1, adverse effects to be exerted on the power supply wiring portion26as a result of the foreign matter reaching the power supply wiring portion26can be suppressed. Further, because air can be led in and led out without being blocked by the LED unit20, the LEDs10can be suitably cooled, and it becomes possible to further improve the operation stability of the LEDs10.

In the LED light source device1configured as in the above, electricity is supplied to the LEDs10of each LED unit20via the power supply wiring portion26, and ultraviolet light is emitted forward from the LEDs10in the LED juxtaposition region R. The ultraviolet light is led to the light transmitting member4to repeat total reflection inside the light transmitting member4, and is increased in its peak amount of light and uniformized. Then, the ultraviolet light is output forward as an output light through an opening O of the front cover2a, and an irradiation object is irradiated with the ultraviolet light.

Meanwhile, when performing a process using light energy by an output light being ultraviolet light, it is preferable that the output light is a predetermined amount or more and uniform across the whole area of an emitting region being a region through which ultraviolet light is extracted from the light source (that is, the whole area of a light emitting surface of the light transmitting member4). However, conventionally, for reasons such that the amount of light of a single LED10is lower than that of a single discharge lamp, and there is a difference in the amount of light between a part where the LED10is disposed in the emitting region and a part between neighboring LEDs10,10, it has been considered difficult to uniformize the amount of light of the emitting region at a predetermined amount or more.

In this regard, because the light transmitting member4shows a rectangular parallelepiped outer shape in the present embodiment, reflection and the like when leading ultraviolet light emitted from the LEDs10to the light transmitting member4can be suppressed as compared to when, for example, a member showing a columnar outer shape (a so-called round rod lens) is used as the light transmitting member4. That is, ultraviolet light can be reliably led to the light transmitting member4, and a decrease (loss) in the amount of output light can be suppressed.

Additionally, as described above, the ends of the light transmitting member4of the present embodiment are located in a range of being inside by ½ of the predetermined width H of the marginal portion11surrounding the emitting surface S to outside by ½ of the predetermined width H with respect to the ends of the LED juxtaposition region R, respectively, when viewed from the front in each of the long side direction and short side direction. Therefore, the amount of light of the emitting region can be made a predetermined amount of light or more and uniformized. This is for the following reasons.

FIG. 14is a graph showing a relationship between the position and light output (amount) of output light in the LED light source device ofFIG. 1. The position (horizontal axis) in the figure shows positions along the long side direction (or short side direction) passing through the emitting region, and the center of the emitting region is represented by a reference (0 mm).

As shown by the broken line ofFIG. 14, when the ends of the light transmitting member4are too far apart inside from the ends of the LED juxtaposition region R, respectively ([End of light transmitting member4]<[End of LED juxtaposition region R]−[Predetermined value α]) in the long side direction, there is provided a distribution of the amount of light gathering toward the center of the emitting region, and the peak amount of light is increased, but the amount of light at end portions of the emitting region is low.

Moreover, as shown by the dotted line ofFIG. 14, when the ends of the light transmitting member4are too far apart outside from the ends of the LED juxtaposition region R, respectively ([End of light transmitting member4]>[End of LED juxtaposition region R]+[Predetermined value α]), the distribution of the amount of light shows a so-called fat-tailed state where the amount of light gradually decreases at end portions, and the peak amount of light decreases. Therefore, in these cases, it is difficult to make the amount of light a predetermined amount of light or more and uniformize the amount of light in the whole area of the emitting region.

On the other hand, as in the present embodiment shown by the solid line ofFIG. 14, when the ends of the light transmitting member4are located in an optimum range ([End of LED juxtaposition region R]—[Predetermined value α]≦[End of light transmitting member4]≦[End of LED juxtaposition region R]+[Predetermined value α]), the peak amount of light can be sufficiently secured, and a rise and fall in the distribution of the amount of light can be made steep to reduce the area of decrease in the amount of light at end portions of the emitting region. Therefore, it becomes possible to make the amount of light of the emitting region a predetermined amount of light or more and uniformize the amount of light.

In addition, as shown by the alternate long and short dashed line ofFIG. 14, it can be understood that, when a round rod lens was used as the light transmitting member4, not only is the peak amount of light low but the use efficiency of ultraviolet light emitted from the LEDs10(integral amount of output light) has also decreased. That is, it can be understood that, in this case, ultraviolet light that had needed to enter the light transmitting member4was intercepted, and the amount of extraction of ultraviolet light from the light transmitting member4was also reduced, and thus the amount of output light has decreased. Moreover, as shown by the alternate long and two short dashed line ofFIG. 14, it can be understood that, when the light transmitting member4was not provided, the peak amount of light has considerably decreased, and a remarkable fat-tailed state was brought about. In connection to this, when a reflector is used in place of the light transmitting member4, loss occurs in reflection of ultraviolet light, and thus loss in the amount of light is increased also in this case.

Moreover, in the present embodiment, as described above, the rear surface4bof the light transmitting member4is in contact with the front surfaces10aof the LEDs10, ultraviolet light emitted from the LEDs10can be reliably led to the light transmitting member4, and it becomes possible to suppress a decrease in the amount of light. As a result, in the LED light source device1, a large amount of output light can be obtained in the emitting region. Moreover, the ultraviolet LED array3and the light transmitting member4come into surface contact, so that a change in the emitting condition of output light as a result of a change in the positional relationship between the ultraviolet LED array3and the light transmitting member4due to an external factor such as vibration can be suppressed.

Moreover, in the present embodiment, as described above, the LEDs10are unitized as the LED unit20. Therefore, handling of the LEDs10in replacement and in manufacturing can be facilitated. Furthermore, the plurality of LED units20are, with the LEDs10juxtaposed so as to be adjacent to each other on the side of the front surface33aof the substrate33, juxtaposed so that the LEDs10are adjacent between the neighboring LED units20. Therefore, the LEDs10can be easily provided in a dense arrangement, and it becomes possible to obtain a large amount of light uniformly in the emitting region.

Moreover, in the present embodiment, as described above, the LEDs10are disposed on the substrate21so that, in the LED unit20, the side surfaces10cof the LEDs10and the side surface21c of the substrate21form the same plane (that is, so that the peripheries of the LEDs10and the periphery of the substrate33become coincident). Therefore, by juxtaposing the LED units20adjacently (making the LED units20neighbor without a gap) according to the emitting region, the LEDs10between the LED units20can also be provided in a dense arrangement, and eventually, the LEDs10can be provided in a dense arrangement for the light source as a whole. As a result, it becomes possible to obtain a larger amount of light uniformly in the emitting region. The same plane in the above implies not only “completely the same” planes but also “substantially the same” planes, in which variations due to, for example, dimensional tolerances and errors in manufacturing are included.

Moreover, in the present embodiment, as described above, the heat dissipating surfaces17of the LEDs10are connected to the thermally conductive plate22via the through-holes24formed in the substrate33, and the heat sink5is connected to the thermally conductive plate22. Therefore, the heat dissipation performance of the LEDs10can be improved, and it becomes possible to improve the operation stability of the LEDs10and prevent output degradation and shortened lifetime of the LEDs10. Particularly, the thermally conductive plate22is not provided for each LED10, but a plurality of LEDs10are collectively connected to the thermally conductive plate22, and thus a heat dissipation plate of a larger heat capacity can be used. As a result, in the LED light source device1, a large amount of output light can be stably obtained.

Moreover, in the present embodiment, as described above, the side surfaces4c,4cof the light transmitting member4are sandwiched by a pressing force of screwing of the pressing members43via the interposing members44, and the side surfaces4d,4dof the light transmitting member4are sandwiched by a pressing force of screwing of the pressing members53via the interposing members54, and accordingly, the light transmitting member4is fixed. By thus fixing the light transmitting member4by mechanical retention, for example, a situation where an adhesive deteriorates under the influence of ultraviolet light when the light transmitting member4is fixed by only adhering fixation, resulting in an insufficient fixing ability can be prevented, and it becomes possible to stably fix the light transmitting member4over a long period of time.

Moreover, as in the above, the interposing members44,54are formed of a material containing a fluororesin that hardly deteriorates because of having high resistance against ultraviolet light and high temperature. Therefore, the ultraviolet resistance property and heat resistance property can be improved with regard to fixation of the light transmitting member. Additionally, because the fluororesin-containing material is softer than quartz, direct exertion of a concentrated stress due to screwing of the pressing members43,53on the light transmitting member4that is a fragile quartz member can be suppressed.

Moreover, screws are used as the pressing members43,53(the pressing members43,53have screw mechanisms), and the light transmitting member4is fixed by a pressing force of screwing, and thus fine adjustment of the pressing force, fine adjustment of the fixing position, and the like can be easily performed.

Moreover, in the present embodiment, the joint portion29, the substrate33, and the main body block52are fixed to each other by inserting the screws31through the through-holes52xof the main body blocks52,52and the through-holes25,35of the LED unit20and screwing. Therefore, it becomes possible to use a fixing structure of the intermediate retaining portion51also as a fixing structure of the LED unit20.

In connection to this, when lamps are used as a light source as in a conventional light source device, the light source has a short lifetime, and it has been difficult to irradiate a heat-sensitive irradiation object, but by using LEDs10as in the present embodiment, it becomes possible to prolong the lifetime, and it becomes possible to irradiate also a heat-sensitive irradiation object. Moreover, the light transmitting member4functions also as, for example, a window member for preventing contamination of the LEDs10due to foreign matter from an irradiation object.

In the above, a preferred embodiment of the present invention has been described, but the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the light transmitting member4is fixed only by mechanical retention with respect to the ultraviolet LED array3, but in addition to this, for example, as shown in the following, the light transmitting member4may be fixed by adhesion with respect to the ultraviolet LED array3.

FIG. 15(a) is a sectional view corresponding toFIG. 3showing an example when the light transmitting member4is fixed by adhesion with respect to the ultraviolet LED array3, andFIG. 15(b) is a sectional view corresponding toFIG. 3showing another example when the light transmitting member4is fixed by adhesion with respect to the ultraviolet LED array3. As shown inFIG. 15(a), when the ends of the light transmitting member4are located inside with respect to the ends of the LED juxtaposition region R, respectively, an adhesive B may be provided in a fillet shape between the front surface10aof the LED10and a side surface49of the light transmitting member4to fix the light transmitting member4by adhesion. Moreover, as shown inFIG. 15(b), when the ends of the light transmitting member4are located inside with respect to the ends of the LED juxtaposition region R, respectively, an adhesive B may be provided in a fillet shape between a side surface19of the LED10and the rear surface4bof the light transmitting member4to fix the light transmitting member4by adhesion.

Thus, by fixing the light transmitting member4by adhesion with respect to the ultraviolet LED array3, the light transmitting member4can be fixed stably and at a low cost. Moreover, in the case of adhesion fixation by providing an adhesive B between the side surface19of the LED10and the rear surface4bof the light transmitting member4, because the adhesive B is disposed on the rear side further than the front surface10aincluding the emitting surface S of the LED10, exertion of adverse effects of ultraviolet light on the adhesive B can be suppressed.

Moreover, in the above-described embodiment, the LEDs10are disposed on the substrate21so that the side surfaces10cof the LEDs10are located on the same plane as the side surface21cof the substrate21, but the LEDs10may be disposed on the substrate21so that the side surfaces10cof the LEDs10project to the outside further than the side surface21c of the substrate21(so that the LEDs10protrude from the substrate21), and the same advantageous effects are obtained.

Moreover, the light transmitting member4of the above-described embodiment is sandwiched and fixed in the long side direction by a pressing force of screwing of the pressing member43, and is sandwiched and fixed in the short side direction by a pressing force of screwing of the pressing member53, but the light transmitting member4may be sandwiched in either the long side direction or short side direction. At this time, it is preferable to sandwich the light transmitting member4in the long side direction because the effect to be exerted on the fixing ability of the light transmitting member4is great as compared with when sandwiching the light transmitting member4in the short side direction. The mechanical retention may be used together with adhesion fixation of the light transmitting member4as in the above, and in some cases, only adhesion fixation may be performed to make mechanical retention unnecessary.

Moreover, in the above-described embodiment, the light transmitting member4and the LED10are in contact with each other, but a predetermined gap may be formed therebetween. Moreover, in the above-described embodiment, the marginal portion11has a rectangular frame shape, but the marginal portion is not limited hereto, and formed according to the shape of the front surface10aof the LED10, and may be formed as a region that is not flush with the emitting surface S in the front surface10a. For example, there may be a step-like shape such that the glass plate14to serve as the emitting surface S is placed on the marginal portion11.

Moreover, in the above-described embodiment, a plurality of

LEDs10are juxtaposed in a matrix to form an LED juxtaposition region R, but LEDs10may be juxtaposed in a line shape to form an LED juxtaposition region R. Moreover, in the LED10, the predetermined width H of the marginal portion11in the short side direction and the predetermined width H of the marginal portion11in the long side direction are provided as the same size, but these widths may be different. In this case, the predetermined value α corresponds to the predetermined width H in each of the short side direction and long side direction.

The LEDs10are disposed so as to closely contact each other in the drawings, but may be disposed with so small a gap therebetween as not to cause variation in the amount of light. In this case, manufacturing of the LED unit20and, eventually, the LED light source device1can be facilitated.

Moreover, fixation of the light transmitting member4is not limited to that of the above-described embodiment, and for example, the light transmitting member4may be fixed in the LED light source device1in the following manner.

FIG. 16is a rear view showing a light transmitting member,FIG. 17is a view showing a part ofFIG. 16in an enlarged manner, andFIG. 18is a schematic view corresponding toFIG. 3showing a light transmitting member. As shown inFIGS. 16 to 18, the light transmitting member4is attached to an inner surface side of the front cover2aof the case2via an O-ring (resin member)42.

At an upper side and a lower side of an opening O in the inner surface of the front cover2a, flanges41x,41yas wall portions extending in the left and right direction are provided, respectively. In the front cover2a, the width (length in the up and down direction) of the opening O is made substantially equal to the width (length in the up and down direction) of the light transmitting member4. The O-ring42is formed of a resin.

For the light transmitting member4here, specifically, the O-ring42is provided so as to wind around its side surfaces4c,4d, and the light transmitting member4is in this state fitted between the flanges41x,41yof the front cover2aso as to be sandwiched between the flanges41x,41y. That is, the light transmitting member4is fixed to the front cover2aas a result of its upper and lower surfaces being sandwiched via the O-ring42by the flanges41x,41y. Therefore, as shown inFIG. 18, the light transmitting member4is brought into contact with the LEDs10so as to be opposed to the front side of the LEDs10as well as fixed to the front cover2awhile being positioned with respect to the LEDs10and the opening O. As a result, the LEDs10face the outside through the opening O via the light transmitting member4.

According to the modification described in the above, because the light transmitting member4is attached to the inner surface side of the front cover2aby fixation via the O-ring42, positioning of the light transmitting member4can be easily performed for fixing the light transmitting member4, and it becomes possible to fix the light transmitting member4simply and accurately in the LED light source device1. Moreover, because the light transmitting member4can be detached from the side of the LEDs10only by removing the front cover2a, maintenance such as cleaning of the light transmitting member4is facilitated. Moreover, it becomes no longer necessary to unfix the light transmitting member4also in replacement of the LEDs10.

Moreover, in the above-described modification, as described above, no wall portions such as flanges are provided at sides in the left and right direction of the opening O, and the O-ring42is not pressed in the left and right direction. Accordingly, a force produced when the light transmitting member4provided with the O-ring42is attached to the front cover2acan be released in the left and right direction (that is, so-called relief portions can be formed in the left and right direction of the front cover2a), so that such attachment can be facilitated, and the possibility of damage to the light transmitting member4during attachment can be reduced. Moreover, the relief portions also allow releasing thermal stress in thermal expansion.

Moreover, in the above-described modification, as described above, the upper and lower side surfaces4d,4dof the light transmitting member4showing a shape that is long in the left and right direction are sandwiched for fixation, and thus the area to be involved in fixation can be increased as compared with when the left and right side surfaces4c,4cof the light transmitting member4are sandwiched for fixation, so that the light transmitting member4can be reliably fixed. Moreover, because the area to be involved in fixation can thus be increased, stress to act on the light transmitting member4when fixing the light transmitting member4can be reduced, and it becomes possible to reduce the possibility of damage to the light transmitting member4.

Moreover, in the above-described modification, as described above, the light transmitting member4is fixed via the O-ring42, and thus in the case of thermal expansion of the light transmitting member4, the O-ring42can be made to act as a buffer, and it becomes possible to further reduce the possibility of damage to the light transmitting member4.

Moreover, the thickness (length in the front and rear direction) of the O-ring42in the above-described modification is thinner than the thickness of the light transmitting member4. Accordingly, for example, a reduction in the amount of light as a result of the O-ring42entering into the emitting region of the LEDs10and a reduction in adhesion between the LEDs10and the light transmitting member4due to the O-ring42can be suppressed.

In addition, the light transmitting member4may be fixed by interposing a plate-shaped resin member between the light transmitting member4and the flanges41x,41yin place of the O-ring42. In connection to this, when the light transmitting member4is fixed by means of the O-ring42as in the above-described modification, the light transmitting member4can be easily fixed to the front cover2abecause of excellent handling ability of the O-ring42.

Industrial Applicability

According to the present invention, it becomes possible to make the amount of light of the emitting region a predetermined amount of light or more and uniformize the amount of light.

REFERENCE SIGNS LIST