Patent Description:
Known is a light source device including a plurality of light emitting elements which are arranged along a predetermined direction in a housing having a great length along the predetermined direction. In the above-described light source device, an intake port and an exhaust port are respectively provided in one end and the other end of the predetermined direction in the housing, to cool the plurality of light emitting elements, in one instance. However, in such an instance, a light emitting element in one end is cooled to a greater extent than a light emitting element in the other end, and thus, light outputs of the plurality of light emitting elements cannot be equalized. Meanwhile, in the above-described light source device, an intake port is provided in a side surface between the one end and the other end in the housing and an exhaust port is provided in the other end of the housing, to cool the plurality of light emitting elements, in another instance. However, in such an instance, a light emitting element in the other end is cooled to a greater extent than a light emitting element in one end, and thus light outputs of the plurality of light emitting elements cannot be equalized.

As a technique for uniformly cooling the plurality of light emitting elements in the above-described light source device, devices described in <CIT> and <CIT> are known, for example. In an LED lighting device described in <CIT>, an LED-equipped substrate which is equipped with a plurality of LEDs is mounted onto a heat dissipation block, and heat of the LEDs is dissipated by the heat dissipation block. In the LED lighting device described in <CIT>, a first channel through which a refrigerant flows from one end to the other end of the heat dissipation block, and a second channel through which a refrigerant flows from the other end to one end of the heat dissipation block, are provided. Thus, the plurality of light emitting elements are cooled.

In an LED unit described in <CIT>, a plurality of LEDs are mounted onto a heat dissipation member including a channel through which a refrigerant flows along a lengthwise direction. In the LED unit described in <CIT>, a refrigerant is introduced into a channel from a lengthwise center, and the foregoing channel includes a channel through which a refrigerant flows from a lengthwise center to one end, and a channel through which a refrigerant flows from a lengthwise center to the other end. Thus, a plurality of light emitting elements are cooled.

In a light source device, it is required to equalize temperatures of a plurality of light emitting elements so that respective light outputs of the plurality of light emitting elements are kept constant. In this regard, because of inclusion of a plurality of exhaust portions, a need of providing a plurality of channels for a refrigerant, or the like, the above-described conventional techniques still have room for improvement from a viewpoint of reducing the number of components or simplifying a configuration. In particular, in a light source device mounted onto a UV printing apparatus, for example, positions and the numbers of intake ports and exhaust ports of the light source devices are limited in order to reduce an influence of air upon an illuminated object (a printed material on which UV-light-curing ink deposits), in some cases.

It is an object of one aspect of the present invention to provide a light source device which can equalize temperatures of a plurality of light emitting elements. <CIT> describes an irradiation device with a top housing hinged to a lower housing. The substrate is transported in a passage between the two housing parts.

A light source device is described in appended claim <NUM>. Other aspects of the invention are described in the dependent claims.

Hereinafter, an embodiment will be described in detail with reference to the drawings. In the following description, the same or corresponding elements will be denoted by the same reference numerals, and duplicated description will be avoided.

As shown in <FIG> and <FIG>, a light source device <NUM> is a high-power air-cooled LED light source for use in printing, for example. The light source device <NUM> can be used as a light source unit which has a great length and is mounted onto a UV printing apparatus (UV printer), for example. The light source device <NUM> emits light such as ultraviolet light, and dries ink, for example. The light source device <NUM> includes a housing <NUM>, a plurality of LED substrates <NUM>, a supporting block <NUM>, a plurality of heat sinks <NUM>, a pair of driving circuits <NUM>, a radial-flow fan <NUM>, and a light shielding case <NUM>.

It is noted that for convenience in description, description will be made assuming that a lengthwise direction (predetermined direction) of the housing <NUM> is an "X direction", a direction in which light is emitted from LED elements <NUM> of the LED substrates <NUM>, being perpendicular to an X direction, is a "Y direction", and a widthwise direction of the light source device <NUM>, being orthogonal to an X direction and a Y direction is a "Z direction". Also, description will be made assuming that a side toward which the LED elements <NUM> emit light is a "lower side" and a side opposite thereto is an "upper side".

The housing <NUM> is in a form of a rectangular box having a great length along an X direction. The housing <NUM> is formed of metal. The housing <NUM> holds the LED substrates <NUM>, the supporting block <NUM>, the heat sinks <NUM>, and the driving circuits <NUM>.

In one end surface (one end) 10a on one side of the housing <NUM> in an X direction, a first intake port <NUM> through which air is sucked into the housing <NUM> from the outside is provided. The first intake port <NUM> is formed so as to open outward in an X direction. A filter 11a formed of urethane or the like, for example, is attached to the first intake port <NUM>. A grip unit <NUM> for gripping the housing <NUM> is provided in the one end surface 10a.

In the other end surface (the other end) 10b on the other side of the housing <NUM> in an X direction, an exhaust port <NUM> through which air is discharged to the outside from the housing <NUM> is provided. The exhaust port <NUM> is connected with a blower <NUM> which sucks air, via a pipe <NUM> having bellows. Accordingly, in the housing <NUM>, a pressure of air on one side in an X direction is higher than that on the other side, and air flows from one side to the other side in an X direction. In the following description, one side in an X direction will be also referred to as an "upstream side", and the other side in an X direction will be also referred to as a "downstream side".

As shown in <FIG>, the housing <NUM> includes a body section <NUM> and a downstream section <NUM> located downstream of the body section <NUM>. An outline of the body section <NUM> takes a shape of a rectangular parallelepiped having a great length along an X direction. An end surface on an upstream side of the body section <NUM> corresponds to the above-described one end surface 10a. In the body section <NUM>, the LED substrates <NUM>, the supporting block <NUM>, and the heat sinks <NUM> are placed. In an upstream portion of a lower surface (lower side surface) of the body section <NUM>, a communication port <NUM> which communicates with a later-described light-shielding-case exhaust port <NUM> of the light shielding case <NUM>, is formed. A lid unit <NUM> in which a plurality of slits are formed is attached to the communication port <NUM>. In a downstream portion of the body section <NUM>, a buffer unit <NUM> serving as a buffer space for buffering an air flow is provided.

The body section <NUM> includes a lower sidewall unit <NUM>, an upper sidewall unit <NUM>, and a pair of sidewall units <NUM> and <NUM> which are continuous with those sidewall units <NUM> and <NUM> and are opposite to each other along a Z direction. In the lower sidewall unit <NUM>, a light emission window <NUM> which allows light provided from the LED substrates <NUM> to pass therethrough is provided. Each of the upper sidewall unit <NUM> and the pair of sidewall units <NUM> and <NUM> which are opposite to each other along a Z direction is configured to have a double-wall structure. The sidewall unit <NUM> includes an outer sidewall 21o and an inner sidewall 21i. The sidewall unit <NUM> includes an outer sidewall 22o and an inner sidewall 22i. The sidewall unit <NUM> includes an outer sidewall 23o and an inner sidewall 23i.

Each of the outer sidewalls 21o, 22o, and 23o is a flat-plate-shaped wall member which forms a periphery of the body section <NUM> (between the first intake port <NUM> and the exhaust port <NUM>). The outer sidewall 21o is provided orthogonally to, and continuously with, the outer sidewalls 22o and 23o. The inner sidewalls 21i, 22i, and 23i are flat-plate-shaped wall members which are placed inwardly with respect to the outer sidewalls 21o, 22o, and 23o, respectively. The inner sidewall 21i is provided orthogonally to, and continuously with, the inner sidewalls 22i and 23i. The inner sidewalls 21i, 22i, and 23i extend along an X direction from a position located downstream of the first intake port <NUM> by a predetermined distance, to the buffer unit <NUM>. Lower ends of the inner sidewalls 22i and 23i are positioned in the neighborhood of centers of a Y direction in the outer sidewalls 22o and 23o.

An inter-wall space <NUM> in which air sucked through the first intake port <NUM> and the communication port <NUM> is allowed to flow along an X direction is formed between the outer sidewalls 21o, 22o, and 23o and the inner sidewalls 21i, 22i, and 23i, respectively. The inter-wall space <NUM> has an inverted-U-shaped longitudinal section in a state shown in <FIG>. Clearances between the outer sidewalls 22o and 23o and the inner sidewalls 22i and 23i are enclosed by lower ends of the inner sidewalls 22i and 23i. In such the inter-wall space <NUM>, portions on an upstream side and a downstream side communicate with the housing <NUM>, and a lower end is blocked.

An outline of the downstream section <NUM> takes a shape of a rectangular parallelepiped of which upper portion protrudes over the body section <NUM>. The downstream section <NUM> is provided continuously with the body section <NUM>. An end surface of the downstream section <NUM> on a downstream side corresponds to the above-described other end surface 10b. The downstream section <NUM> is partitioned into a wire holding space <NUM> and a ventilation space <NUM> by a partition plate <NUM> in a shape of a flat plate extending along an X-Z plane. The wire holding space <NUM> is a space above the partition plate <NUM> in the downstream section <NUM>, and is defined (demarcated) in an upper portion within the downstream section <NUM>. In the wire holding space <NUM>, a wire C1 is collectively held. The ventilation space <NUM> is a space in which air flows, and communicates with the body section <NUM> and the exhaust port <NUM>. The ventilation space <NUM> is a space below the partition plate <NUM> in the downstream section <NUM>. In the ventilation space <NUM>, the pair of driving circuits <NUM> are placed.

The LED substrates <NUM> include substrates each of which forms a predetermined circuit and has a shape of a rectangular plate, and the LED elements <NUM> serving as light emitting elements which are arranged side by side with predetermined pitches along an X direction and a Y direction on those substrates. The LED elements <NUM> emit light such as ultraviolet light downward. The LED substrates <NUM> are arranged side by side along an X direction on a lower surface of the supporting block <NUM>. Accordingly, several to several hundreds of LED elements <NUM> are arranged along at least an X direction in the housing <NUM>. Light emitted from each of the LED elements <NUM> of the plurality of LED substrates <NUM> is irradiated, via the light emission window <NUM> of the housing <NUM>, to an illuminated object which passes through a later-described passage area R. As an illuminated object, a printed material on which light-(UV-light-) curing ink deposits is cited, for example.

The supporting block <NUM> is formed of metal and is placed on a lower side in the body section <NUM> of the housing <NUM>. The plurality of LED substrates <NUM> are arranged side by side along an X direction on a lower surface of the supporting block <NUM>. On an upper surface of the supporting block <NUM>, the plurality of heat sinks <NUM> are arranged side by side along an X direction. Notches <NUM> each of which is a portion cut out in a rectangular shape in a longitudinal section are formed to extend along an X direction, on lower sides of opposite ends of a Z direction in the supporting block <NUM> (refer to <FIG>). The notches <NUM>, in collaboration with the sidewall unit <NUM> of the housing <NUM>, form lower spaces <NUM>. In other words, the lower spaces <NUM> are defined by the notches <NUM> and the sidewall unit <NUM>.

The lower space <NUM> extends from an upstream portion of the body section <NUM> to a position ahead of the buffer unit <NUM> (a position located upstream of the buffer unit <NUM>) along an X direction. The lower space <NUM> is partitioned into an upper portion and a lower portion by a partition plate <NUM>. Accordingly, in the lower space <NUM>, a first lower space <NUM> and a second lower space <NUM> above the first lower space <NUM> are formed. The first lower space <NUM> mainly serves as a space in which air sucked through the first intake port <NUM> and the communication port <NUM> is allowed to flow along an X direction. The first lower space <NUM> allows air to flow along an inner surface of the sidewall unit <NUM> of the housing <NUM>, to thereby suppress temperature rise of the sidewall unit <NUM>. The second lower space <NUM> mainly serves as a space in which a wire C2 is collectively held.

The heat sinks <NUM> are heat dissipation members which are thermally connected with the LED elements <NUM> of the LED substrates <NUM>. The plurality of (three in this embodiment) heat sinks <NUM> are placed on an upper surface of the supporting block <NUM>, so as to be arranged at predetermined intervals along an X direction. The heat sink <NUM> includes a base <NUM> and a plurality of heat dissipation fins <NUM>.

The base <NUM> takes a shape of a rectangular plate. The base <NUM> is connected with an upper surface of the supporting block <NUM>. Accordingly, the base <NUM> is thermally coupled to the LED elements <NUM> of the LED substrates <NUM> via the supporting block <NUM>. The heat dissipation fin <NUM> takes a shape of a flat plate having a width along a Z direction and a great length along an X direction. The heat dissipation fins <NUM> are arranged so as to be stacked at some intervals along a Z direction. The heat dissipation fins <NUM> are erected on the base <NUM>.

In the heat dissipation fins <NUM>, notches <NUM> are formed. The notches <NUM> are portions resulted from cutting-out of respective portions of the plurality of heat dissipation fins <NUM>. More specifically, the notches <NUM> are portions resulted from cutting-out of respective upper corners of the plurality of rectangular heat dissipation fins <NUM> in rectangular shapes when seen from a Z direction. That is, when seen from a Z direction, the heat dissipation fin <NUM> has a shape which protrudes upward in a form of a rectangular pulse, and the notch <NUM> is formed by a level difference provided in each of opposite ends of an X direction in the heat dissipation fin <NUM>. The notch <NUM> in this embodiment extends to the neighborhood of a center of a Y direction in the heat dissipation fin <NUM> (refer to <FIG>).

The heat dissipation fins <NUM> are erected in an area not including opposite ends of a Z direction on the base <NUM>. In other words, an area where the heat dissipation fins <NUM> are not provided is formed in each of opposite ends of a Z direction on the base <NUM>. In the opposite ends of a Z direction on the base <NUM>, the sidewall units <NUM> and <NUM> each having a double-wall structure are placed respectively.

The driving circuits <NUM> are electric driving-circuit boards for driving the light source device <NUM>. The driving circuits <NUM> are placed so as to be paired with each other in the ventilation space <NUM> of the downstream section <NUM>. Accordingly, the driving circuits <NUM> are placed downstream of the LED substrates <NUM> by a predetermined distance or larger along an X direction. In this embodiment, the driving circuits <NUM> are located downstream of the LED substrates <NUM> by some distance with the buffer unit <NUM> being interposed therebetween.

The pair of driving circuits <NUM> are placed in such a manner that respective component mounting surfaces 60a face each other along a direction crossing an X direction (a Y direction in this embodiment). More specifically, one of the driving circuits <NUM> is placed on a lower side in the ventilation space <NUM> in such a manner that the component mounting surface 60a faces upward. The other of the driving circuits <NUM> is placed on an upper side in the ventilation space <NUM> in such a manner that the component mounting surface 60a faces downward.

The driving circuit <NUM> includes a circuit heat sink <NUM> which dissipates heat of the driving circuit <NUM>. The circuit heat sink <NUM> is provided in the component mounting surface 60a. The pair of driving circuits <NUM> are placed in such a manner that the respective circuit heat sinks <NUM> do not overlap each other along an X direction. In an example shown in the drawings, the pair of driving circuits <NUM> have a positional relationship in which the driving circuits <NUM> are symmetrical with respect to a point between the driving circuits <NUM> when seen from a Z direction.

The radial-flow fan <NUM> is fixed to a lower surface of the downstream section <NUM> of the housing <NUM>. The radial-flow fan <NUM> sucks air from a lower side along a Y direction and feeds the air under pressure to one side of an X direction (an upstream side of air in the housing <NUM>).

The light shielding case <NUM> is in a form of a rectangular box which has a great length along an X direction and is flattened along a Y direction. The light shielding case <NUM> is formed of metal. The light shielding case <NUM> is removably attached on a lower side in the body section <NUM> of the housing <NUM>, and protects the light emission window <NUM> of the body section <NUM> from light. The light shielding case <NUM> is inserted into an air-outlet side of the radial-flow fan <NUM>, and the inside of the light shielding case <NUM> communicates with an air-outlet side of the radial-flow fan <NUM>. In an upper surface of the light shielding case <NUM>, a groove <NUM> which defines the passage area R is formed. The passage area R is an area where an illuminated object passes along a Z direction. A bottom surface of the groove <NUM> faces the light emission window <NUM>. In an upper surface on one side in an X direction in the light shielding case <NUM>, the light-shielding-case exhaust port <NUM> through which air is discharged from the light shielding case <NUM> is formed. The light-shielding-case exhaust port <NUM> communicates with the communication port <NUM> of the housing <NUM> while the light shielding case <NUM> is attached to the housing <NUM>.

Within the light shielding case <NUM> configured in the above described manner, air which is sucked and fed under pressure by the radial-flow fan <NUM> flows from the other side to one side in an X direction (in a direction reverse to a direction of an air flow in the housing <NUM>) in the light shielding case <NUM>. Accordingly, a bottom surface of the groove <NUM> of which temperature is increased by light which is provided through the light emission window <NUM> and falls on the bottom surface, is cooled. The air flows into an upstream portion of the housing <NUM> through the light-shielding-case exhaust port <NUM> via the communication port <NUM>, and merges with air sucked through the first intake port <NUM>. As a result of this, the air sucked through the first intake port <NUM> flows from one side to the other side in an X direction, together with the air provided from the light shielding case <NUM>.

It is noted here that a space <NUM> of which downstream side (the other side in an X direction) faces the heat sinks <NUM> is formed in the housing <NUM>. In other words, upstream sides of the heat dissipation fins <NUM> of the heat sinks <NUM> face the space <NUM>. The heat dissipation fins <NUM> are placed downstream of the space <NUM>.

The space <NUM> is a place where the heat dissipation fins <NUM> are not provided in the housing <NUM>. The space <NUM> has a certain volume or higher. The space <NUM> is a vacant place in the housing <NUM>. The space <NUM> is formed between a pair of adjacent heat sinks <NUM>. The space <NUM> is defined by the notches <NUM> formed in the respective heat dissipation fins <NUM> of a pair of adjacent heat sinks <NUM>. More specifically, the space <NUM> is defined by the respective notches <NUM> of a pair of adjacent heat sinks <NUM> and the inner sidewalls 21i, 22i, and 23i, and takes a shape of a rectangular parallelepiped.

A plurality of (two in this embodiment) second intake ports <NUM> through which air is sucked from the outside into the space <NUM> are provided in each of the respective side surfaces 22a and 23a of the pair of sidewall units <NUM> and <NUM> in the body section <NUM>. That is, the plurality of second intake ports <NUM> which connect the space <NUM> directly to the outside are formed in each of the side surfaces 22a and 23a between the first intake port <NUM> and the exhaust port <NUM> in the housing <NUM>.

The second intake port <NUM> opens in a Z direction. The second intake port <NUM> includes an outer lid in which a plurality of slits are formed. A filter <NUM> formed of urethane or the like, for example, is attached to the second intake port <NUM>. The second intake port <NUM> is provided in a position where the second intake port <NUM> overlaps the space <NUM> when seen from a Z direction. The space <NUM> is positioned in the neighborhood of (around) the second intake ports <NUM>. The second intake port <NUM> which is formed in the side surface 22a and the second intake port <NUM> which is formed in the side surface 23a face each other along a Z direction. The second intake ports <NUM> are provided in an upper end (that is, an end spaced apart from an illuminated object) of each of the side surfaces 22a and 23a.

The second intake ports <NUM> are provided so as not to communicate with the inter-wall space <NUM> while communicating with the space <NUM>. For example, the second intake port <NUM> includes a through hole which penetrates the outer sidewall 22o and the inner sidewall 22i, and the through hole is closed to the outer sidewall 22o and the inner sidewall 22i. The second intake port <NUM> penetrates the inter-wall space <NUM> until it reaches the space <NUM> while keeping itself from communicating with the inter-wall space <NUM>.

In this connection, a cover <NUM> with which the passage area R is covered is attached to a lower end of each of the side surfaces 22a and 23a of the housing <NUM>. The cover <NUM> is a plate member having a width along a Z direction and a great length along an X direction. The cover <NUM> protects the passage area R from light.

As described above, in the light source device <NUM>, while air sucked through the first intake port <NUM> on one side in an X direction is flowing along an X direction toward the exhaust port <NUM> on the other side in the housing <NUM>, fresh air provided from the outside is sucked into the space <NUM> in the housing <NUM> via the second intake ports <NUM> in the side surfaces 22a and 23a. Since a downstream side of the space <NUM> faces the heat dissipation fins <NUM> of the heat sinks <NUM>, the fresh air sucked into the space <NUM> easily flows into the heat sinks <NUM> (among the heat dissipation fins <NUM>) on a downstream side.

Accordingly, temperature rise of the LED elements <NUM> which are provided on a side close to the exhaust port <NUM> and are easily subjected to temperature rise can be effectively suppressed. A temperature gradient among the plurality of LED elements <NUM> can be reduced, and a difference in temperature between the LED element <NUM> in the neighborhood of the first intake port <NUM> and the LED element <NUM> in the neighborhood of the exhaust port <NUM> can be reduced, so that temperatures of the plurality of LED elements <NUM> can be equalized. An efficiency of cooling the light source device <NUM> as a whole can be increased, which makes it possible to miniaturize the device. An illuminance gradient among the plurality of LED elements <NUM> is reduced, so that a difference in illuminance between the LED element <NUM> in the neighborhood of the first intake port <NUM> and the LED element <NUM> in the neighborhood of the exhaust port <NUM> can be reduced.

In the light source device <NUM>, the space <NUM> is defined by the notches <NUM> formed in the heat dissipation fins <NUM>. Because of such a configuration of the space <NUM>, it is possible to effectively achieve a technique in which fresh air is sucked from the outside via the second intake ports <NUM> and is allowed to flow among the heat dissipation fins <NUM>.

In the light source device <NUM>, the space <NUM> is formed between a pair of adjacent heat sinks <NUM>. In this situation, in a case where the plurality of heat sinks <NUM> are placed, the space <NUM> can be efficiently formed.

In the light source device <NUM>, the space <NUM> is defined by the notches <NUM> formed in the respective heat dissipation fins <NUM> of a pair of adjacent heat sinks <NUM>. Because of such a configuration of the space <NUM>, in a case where the plurality of heat sinks <NUM> are placed, it is possible to effectively achieve a technique in which fresh air is sucked from the outside via the second intake ports <NUM> and is allowed to flow among the heat dissipation fins <NUM>.

In the light source device <NUM>, the second intake ports <NUM> are provided in respective ends on an upper side spaced apart from an illuminated object in the side surfaces 22a and 23a. In this situation, mist or the like which is possibly produced from an illuminated object can be prevented from being sucked into the housing <NUM> via the second intake ports <NUM>.

In the light source device <NUM>, each of the sidewall units <NUM>, <NUM>, and <NUM> of the housing <NUM> has a double-wall structure, and the inter-wall space <NUM> in which air sucked through the first intake port <NUM> is allowed to flow along an X direction is formed. The second intake ports <NUM> are provided so as not to communicate with the inter-wall space <NUM> while communicating with the space <NUM>. Accordingly, air sucked through the first intake port <NUM> is allowed to flow in the inter-wall space <NUM>, and so it is possible to surely allowing outside fresh air sucked through the second intake ports <NUM> to flow into not the inter-wall space <NUM>, but the space <NUM>, and then, among the heat dissipation fins <NUM>, while suppressing temperature rise of the sidewall units <NUM>, <NUM>, and <NUM> of the housing <NUM>.

<FIG> is a perspective view for showing a simulation result of an air flow around the second intake ports <NUM>. In <FIG>, an air flow is shown by stream lines. The simulation result in <FIG> indicates that fresh air which is sucked into the space <NUM> in the housing <NUM> via the second intake ports <NUM> can be surely allowed to flow among the heat dissipation fins <NUM> on a downstream side.

<FIG> is a section view for showing a simulation result of temperature distribution in the housing <NUM>. In <FIG>, a level of a temperature is shown by a color gradation, and a darker color means a lower temperature. A section in <FIG> corresponds to a section in <FIG> except that the buffer unit <NUM> and the radial-flow fan <NUM> are omitted. The simulation result in <FIG> indicates that temperature rise of the LED element <NUM> which is provided on a side close to the exhaust port <NUM> and is easily subjected to temperature rise is suppressed and a temperature gradient among the plurality of LED elements <NUM> is reduced, so that temperatures of the plurality of LED elements <NUM> can be equalized.

In the light source device <NUM>, a temperature of the light shielding case <NUM> may possibly be increased to approximately <NUM>, for example, when light emitted via the light emission window <NUM> falls on the light shielding case <NUM>. In this situation, a temperature of the sidewall unit <NUM> on a lower side in the housing <NUM> may possibly be increased under the influence of heat of the light shielding case <NUM>. In this regard, in the light source device <NUM>, the lower space <NUM> (the first lower space <NUM>) in which air is allowed to flow along an inner surface of the sidewall unit <NUM> of the housing <NUM> is provided. This can suppress temperature rise of the sidewall unit <NUM>.

In the light source device <NUM>, the filter <NUM> is attached to the second intake port <NUM>. Accordingly, dust can be prevented from entering into the housing <NUM> via the second intake port <NUM>.

In the light source device <NUM>, the driving circuits <NUM> are placed downstream of the LED substrates <NUM> by a predetermined distance or larger along an X direction. More specifically, the driving circuits <NUM> are located downstream of the LED substrates <NUM> by some distance with the buffer unit <NUM> being interposed therebetween, and are provided in an end on a downstream side in the housing <NUM> in this embodiment. Accordingly, it is possible to prevent heat of the driving circuits <NUM> from adversely affecting cooling of the LED elements <NUM>. The driving circuits <NUM> are cooled by air used for cooling the LED elements <NUM>, and thus, an efficiency of cooling of the light source device <NUM> as a whole can be increased. The driving circuits <NUM> can be cooled by air of which flow is buffered by the buffer unit <NUM>.

The light source device <NUM> includes the pair of driving circuits <NUM>. The pair of driving circuits <NUM> are placed in such a manner that the respective circuit heat sinks <NUM> do not overlap each other along an X direction. This configuration allows heat of the respective circuit heat sinks <NUM> to be effectively dissipated by air flowing along an X direction.

In the light source device <NUM>, the downstream section <NUM> of the housing <NUM> is partitioned into the wire holding space <NUM> and the ventilation space <NUM> by the partition plate <NUM>. Accordingly, a space in which the wire C1 is held and a space in which air flows are separated from each other, so that it is possible to prevent an air flow from becoming turbulent due to presence of the wire C1.

The light source device <NUM> includes the light shielding case <NUM>. With the light shielding case <NUM>, it is possible to shut out light emitted via the light emission window <NUM> while forming the passage area R where an illuminated object passes or is placed.

In the light source device <NUM>, in a space inside the light shielding case <NUM>, air flows in a reverse direction (from the other side to one side in an X direction) with respect to an air flow in the housing <NUM>. With this configuration, by causing air to flow within the light shielding case <NUM>, it is possible to effectively cool a downstream side of the housing <NUM> which is easily subjected to temperature rise while suppressing temperature rise of the light shielding case <NUM> due to light falling thereon via the light emission window <NUM>.

One aspect of the present invention is not limited to the above-described embodiment, and can be altered within a scope not changing the gist recited in claims, or can be applied to the other designs.

Though the plurality of heat sinks <NUM> are provided in the above-described embodiment, a single heat sink <NUM> having a great length along an X direction may be provided as show in <FIG>, for example. The space <NUM> may be defined by the notches <NUM> which are grooves or recesses formed in the heat dissipation fins <NUM> of the single heat sink <NUM>.

Though the second intake ports <NUM> are provided in upper ends of the side surfaces 22a and 23a in the above-described embodiment, the positions of the second intake ports <NUM> in the side surfaces 22a and 23a are not limited to any specific positions. For example, as shown in <FIG>, the notches <NUM> each of which extends to a position near to the base <NUM> along a Y direction may be formed in the heat dissipation fins <NUM>, and the second intake ports <NUM> may be provided in longitudinal centers in the side surface 23a.

Though the space <NUM> is defined by the notches <NUM> provided in the heat dissipation fins <NUM> of the heat sinks <NUM> in the above-described embodiment, the notches <NUM> can be omitted on condition that a downstream side of the space <NUM> faces the heat dissipation fins <NUM>. For example, as shown in <FIG>, each of the heat dissipation fins <NUM> may be formed in a shape of a rectangular plate in which the notch <NUM> (refer to <FIG>) is not provided, and the space <NUM> may be formed between the plurality of heat sinks <NUM>.

Though the second intake ports <NUM> are provided in the side surfaces 22a and 23a in the above-described embodiment, configurations of the second intake ports <NUM> are not limited to that. The second intake ports <NUM> may be provided in at least one of the side surfaces 22a and 23a, and as alternative to that, or in addition to that, the second intake ports <NUM> may be provided in an upper side surface (a side surface of the sidewall unit <NUM>). Regarding the number of the second intake ports <NUM>, either one second intake port <NUM> or a plurality of second intake ports <NUM> may be provided in each side surface. The number of the second intake ports <NUM> may be determined in accordance with a temperature gradient among the plurality of LED elements <NUM>.

Each of the heat sinks <NUM> may include a heat pipe in the above-described embodiment. In the above-described embodiment, a third intake port through which air is sucked into the buffer unit <NUM> from the outside may be further included in a position where the third intake port faces the buffer unit <NUM> in a side surface between the first intake port <NUM> and the exhaust port <NUM> of the housing <NUM>.

Though the plurality of LED substrates <NUM> in which the plurality of LED elements <NUM> are provided are arranged side by side along an X direction in the above-described embodiment, the manner in which the LED substrates <NUM> and the LED elements <NUM> are arranged is not limited to any specific manner, and it will be sufficient if the plurality of LED elements <NUM> are arranged along at least an X direction. Also, a light emitting element is not limited to the LED element <NUM>, and the other known light emitting element may be used.

Claim 1:
A light source device comprising:
a housing (<NUM>) configured to have a great length along a predetermined direction (X);
a plurality of light emitting elements (<NUM>) disposed in the housing (<NUM>) and arranged along at least the predetermined direction (X);
one or a plurality of heat dissipation members (<NUM>) disposed in the housing (<NUM>) and thermally connected with the light emitting elements (<NUM>); and
a light shielding case (<NUM>), wherein
a first intake port (<NUM>) through which air is sucked into the housing (<NUM>) from outside is provided in one end (10a) on one side of the housing (<NUM>) in the predetermined direction (X),
an exhaust port (<NUM>) through which air is discharged to the outside from the housing (<NUM>) is provided in another end (10b) on an other side of the housing (<NUM>) in the predetermined direction (X),
the light shielding case (<NUM>) being removably attached to the housing (<NUM>),
the light shielding case (<NUM>) being configured to shut out light emitted from the light source device (<NUM>),
the housing (<NUM>) is provided with a light emission window (<NUM>) configured to allow light from the light emitting elements (<NUM>) to pass therethrough,
the light shielding case (<NUM>) is attached to the housing (<NUM>) so as to shield light from the light emission window (<NUM>), and
a surface of the light shielding case (<NUM>) is formed with a passage area (R) allowing passage of an illuminated object along a direction perpendicular to the predetermined direction (X),