JP2021073652A - Light source device - Google Patents

Abstract

To provide a light source device which includes a plurality of LED elements and which can restrain illuminance from being decreased by a positional deviation.SOLUTION: A light source device includes: a light source part in which a plurality of LED elements are arrayed; a first optical system that collimates each ray of light emitted from the light source part; and a second optical system that gathers the plurality of rays of light emitted from the first optical system. At least one of the light source part and the first optical system comprises an adjustment mechanism for adjusting a relative positional relationship between the light source part and the first optical system.SELECTED DRAWING: Figure 1

Description

The present invention relates to a light source device, and more particularly to a light source device including a plurality of LED elements.

Conventionally, light processing technology utilizing light has been used in various fields. For example, an exposure apparatus is used for microfabrication using light. In recent years, exposure technology has been developed in various fields, and is used for producing relatively large patterns and three-dimensional microfabrication among microfabrication. More specifically, exposure technology is used, for example, in the production of LED electrode patterns and the manufacturing process of MEMS (Micro Electro Mechanical Systems) represented by acceleration sensors.

In these light processing techniques, a discharge lamp having high brightness has long been used as a light source. However, with the recent progress of solid-state light source technology, it has been studied to use a light source in which a plurality of LED elements are arranged. As such a technique, for example, Patent Document 1 discloses an exposure apparatus in which a unit composed of a plurality of LED elements is used as a light source and a fly-eye lens is arranged between the light source and a mask.

Japanese Unexamined Patent Publication No. 2004-335953

Compared with a light source device in which the light source is composed of a lamp, the emitted luminous flux is smaller when the light source is composed of an LED element. Therefore, in order to configure a light source device that realizes a high light output, it is necessary to collect the emitted light from a plurality of LED elements as much as possible. At this time, if a positional shift occurs between the plurality of LED elements and the subsequent optical system, it is not possible to guide a sufficient amount of light to the target optical system for which light is used. Such misalignment occurs more or less inevitably.

In view of the above problems, it is an object of the present invention to provide a light source device including a plurality of LED elements, which can suppress a decrease in illuminance due to misalignment.

The light source device according to the present invention is
A light source unit in which multiple LED elements are arranged, and
The first optical system that collimates the light emitted from the light source unit, and
A second optical system that collects a plurality of lights emitted from the first optical system is provided.
At least one of the light source unit and the first optical system is provided with an adjusting mechanism for adjusting the relative positional relationship between the light source unit and the first optical system.

As described above, the light emitted from one LED element has a lower brightness than the lamp. Therefore, when it is assumed that the light source is used as a light source for an application that requires a large amount of light, such as an exposure apparatus, it is important to collect the light of many LED elements without reducing the brightness as much as possible. ..

According to the above configuration, the light emitted from the plurality of LED elements is collimated in the first optical system and then condensed. As a result, the emitted light from each LED element can be imaged at the condensing position. Further, the emitted light from each LED element can narrow the distance between the emitted light fluxes by adjusting the arrangement of the collimating lens (first optical system), and a light source having a small non-light emitting region is configured. As a result, a light source device having high brightness is realized.

Then, in such a configuration, if a misalignment occurs between the light source unit and the first optical system, it is assumed that the amount of light guided to the subsequent stage of the second optical system decreases. Specifically, for example, if the positional relationship between each LED element and the corresponding collimating lens (first optical system) is individually deviated, the focusing position of the second optical system will be changed. It will be displaced, and it will be difficult to efficiently guide the light to the subsequent stage of the second optical system. As a result, the amount of light guided to the subsequent stage of the second optical system is reduced, and when used as an exposure apparatus, for example, the illuminance on the exposed surface is reduced.

According to the above configuration, an adjustment mechanism for adjusting the relative positional relationship between the light source unit and the first optical system is provided. Therefore, even when the light source device is installed in a state where the position shift occurs between each LED element included in the light source unit and the corresponding collimating lens (first optical system), the adjustment mechanism By adjusting through the light source, it is possible to correct the deviation of the light source position due to the second optical system, and the light is efficiently guided to the subsequent stage of the second optical system.

The plurality of LED elements are arranged on a predetermined plane, and the plurality of LED elements are arranged on a predetermined plane.
The adjusting mechanism may be configured so that the relative positional relationship between the light source unit and the first optical system can be adjusted in a direction parallel to the predetermined plane.

Further, the adjusting mechanism may be configured so that at least one of the light source unit and the first optical system can be rotated on a plane parallel to the predetermined plane.

Further, as a specific embodiment, the LED board in which the light source unit is housed may be provided, and the adjusting mechanism may be attached to the LED board, or a lens holder in which the first optical system is housed. The adjustment mechanism may be attached to the lens holder.

Further, in the above configuration, the incident surface may include an integrator optical system arranged at the focal position of the second optical system.

The light emitted from the LED element has a smaller luminous flux than the lamp. Therefore, for example, in order to use it as a light source device for exposure, it is necessary to collect the emitted light from a plurality of LED elements as much as possible. For this purpose, it is necessary to increase the number of LED elements arranged as a light source.

By the way, since the wiring pattern for power supply is indispensable for the LED element, the LED element itself cannot be arranged completely in close contact with each other. That is, when arranging a plurality of LED elements, there is no choice but to leave a certain distance between adjacent LED elements. The region forming this interval constitutes a region (non-light emitting region) that does not emit light. Therefore, even if a plurality of LED elements are simply arranged and the emitted light from each LED element is collected, a non-light emitting region is inevitably generated. Therefore, simply condensing the light emitted from the plurality of LED elements causes a decrease in the brightness on the irradiation surface.

According to the above configuration, the light emitted from the plurality of LED elements is collimated in the first optical system and then condensed. As a result, the emitted light from each LED element can be imaged at the condensing position. Further, the emitted light from each LED element can narrow the distance between the emitted light fluxes by adjusting the arrangement of the collimating lens (first optical system), and a light source having a small non-light emitting region is configured. .. As a result, a light source device having high brightness is realized.

Further, the integrator optical system may be composed of a light guide member that guides the light incident from the incident surface to the injection surface while repeatedly reflecting the light on the inner surface.

According to this configuration, light having high radiant intensity is focused on the incident surface of the light guide member, so that light having high brightness and uniform illuminance distribution is emitted from the emission surface of the light guide member. be able to. The light guide member may be, for example, a rod integrator or a light tunnel.

Further, the integrator optical system may be composed of a fly-eye lens in which a plurality of lenses are arranged in a matrix.

The fly-eye lens can make the illuminance distribution on the irradiation surface uniform. As a result, it is possible to realize a light source device having high brightness and a uniform illuminance distribution.

According to the present invention, in a light source device provided with a plurality of LED elements, even when a positional deviation occurs between the optical system and the LED element, it is possible to suppress a decrease in brightness and illuminance due to the positional deviation. Can be done.

It is a drawing which shows typically an example of the optical system of a light source apparatus. It is a drawing which shows typically an example of the arrangement relation between a light source part and the first optical system. It is a drawing which shows typically an example of the arrangement relation between a light source part and the first optical system. It is a drawing which shows typically an example of the arrangement relation between a light source part and the first optical system. It is a drawing which shows typically the image on the incident surface of a rod integrator before the position adjustment. It is a drawing which shows typically the image on the incident surface of a rod integrator after the adjustment of the first step. It is a drawing which shows typically the image on the entrance plane of a rod integrator after the adjustment of the 2nd step. It is a drawing which shows typically the image on the incident surface of a rod integrator after the adjustment of the 3rd stage. It is a drawing which shows typically an example of the arrangement relation between a light source part and the first optical system. It is a drawing which shows typically an example of the arrangement relation between a light source part and the first optical system. It is a drawing which shows typically an example of the optical system of a light source apparatus. It is a drawing which shows typically an example of the structure of an exposure apparatus.

Hereinafter, the light source device of the present invention will be described with reference to the drawings. The dimensional ratio in each figure does not always match the actual dimensional ratio.

FIG. 1 is a drawing schematically showing an example of an optical system of a light source device. The light source device 1 includes a light source unit 2, a first optical system 5, a second optical system 7, and an integrator optical system 8. In the light source device 1 of the present embodiment, the light source unit 2 is housed in the LED board 22, and the first optical system 5 is housed in the lens holder 23. Although not shown in FIG. 1, the LED board 22 and the lens holder 23 are configured so that the relative positional relationship between them can be adjusted. An example of a specific configuration will be described later.

The light source unit 2 includes a plurality of LED elements 3. In the present embodiment, as an example, the plurality of LED elements 3 are arranged on a predetermined plane. However, in the present invention, the arrangement mode of the plurality of LED elements 3 may be any.

The first optical system 5 is an optical system that collimates the light emitted from the plurality of LED elements 3, and a plurality of collimating lenses 6 are arranged and configured corresponding to each LED element 3.

The second optical system 7 is an optical system that focuses the light emitted from the first optical system 5 on the focal point 7f of the second optical system 7.

In this embodiment, the integrator optical system 8 is composed of a rod integrator 9. The rod integrator 9 is arranged so that its incident surface 9a is at the position of the focal point 7f of the second optical system 7. However, in the present specification, "placed in the focal position" means that the focal length is completely aligned with the focal length, and that the focal length is moved in a direction parallel to the optical axis 11 by ± 10%. It shall be a concept including position. The optical axis 11 in FIG. 1 is an axis orthogonal to the incident surface of the integrator optical system 8, that is, the incident surface 9a of the rod integrator 9.

The rod integrator 9 is a light guide member having a function of equalizing the illuminance distribution of light on the injection surface 9b by guiding the light incident on the incident surface 9a to the injection surface 9b while repeating total reflection on the side surface. This is an example of (optical guide). Such a light guide member is composed of, for example, a columnar member made of a light-transmitting material such as glass or resin, a hollow member whose inner surface is made of a reflector, and the like. The latter configuration is sometimes referred to as a light tunnel in particular. In the light guide member, a plurality of optical paths may be divided in a direction parallel to the optical axis.

2, FIG. 3, and FIG. 4 are drawings showing an example of the arrangement relationship between the light source unit 2 and the first optical system 5, respectively. In the example shown in FIG. 2, the LED board 22 in which the light source unit 2 is housed and the lens holder 23 in which the first optical system 5 is housed are integrally held by screws or the like. Note that FIG. 2 shows a clamping screw 41 provided separately from the screw. The clamping screw 41 is an example of the adjusting mechanism.

FIG. 3 is an example of a schematic plan view when the inside of FIG. 2 is viewed from the LED board 22 side. Further, FIG. 4 is a perspective view schematically showing the inside of FIG. 2. In this example, the LED board 22 and the lens holder 23 are configured so that the positional relationship can be adjusted by the three clamping screws 41 and the two ball plungers 42. In FIG. 4, for convenience of illustration, a part of the clamping screw 41 and the ball plunger 42 are not shown.

The ball plunger 42 has a built-in spring. When the three clamping screws 41 are pushed and pulled in a state where the screws between the LED board 22 and the lens holder 23 are slightly loosened, the hard ball at the tip of the ball plunger 42 moves. By this movement, the relative positional relationship between the LED board 22 and the lens holder 23 can be adjusted. Specifically, as shown in FIG. 3, movement in the X direction, movement in the Y direction, and rotational movement in the θ direction are possible. It should be noted that a plurality of LED elements 3 are arranged on a plane (XY plane) composed of the X direction and the Y direction referred to here.

The relative positional relationship between the LED board 22 and the lens holder 23 is actually operated by operating the adjustment mechanism (clamping screw 41 in this example) with the plurality of LED elements 3 constituting the light source unit 2 lit. The image of the rod integrator on the incident surface 9a was measured while adjusting the above. Each figure of FIGS. 5A to 5D is a schematic representation of a photograph of an image at each time point. In each figure, the reference region is indicated by reference numeral 61, and the region appearing as an image is indicated by reference numeral 60. Further, the position at the center of the image 60 is indicated by reference numeral 62. Here, it is assumed that the light source unit 2 is configured by arranging 85 LED elements 3 in an area of 80 mm □.

As an example, the clamping screw 41 can be moved in the front-rear direction of 0.4 mm by making one round, and can be moved by 0.1 mm by making a quarter turn. Further, as shown in FIG. 3, the lens holder 23 can be rotated with respect to the LED board 22 by relatively moving the two clamping screws 41 provided on the same side. As an example, assuming that the distance between the two clamping screws 41 is 60 nm, in order to rotate the light source unit 2 of 80 mm □ by 1 °, the relative positional relationship between the two clamping screws 41 is about 1 mm. It can be realized by shifting (two and a half laps). At this time, the relative positional relationship may be shifted by advancing or retreating only one of the two clamping screws 41, and one of them may be advanced and the other may be retracted. By making it, the relative positional relationship may be shifted.

FIG. 5A corresponds, for example, at the initial stage. According to FIG. 5A, it can be seen that the center 62 of the image is deviated from the center O of the reference region 61. Further, since the image 60 has a circular shape and the image 60 is blurred, it can be seen that it cannot be said that the light from each LED element 3 is focused on substantially the same place. Such a situation suggests that the position shift occurs between the light source unit 2 and the first optical system 3.

FIG. 5B is a result of measurement after the lens holder 23 is rotated and moved by 1 ° with respect to the LED board 22 by operating the adjustment mechanism from the state of FIG. 5A. The image 60 shown in FIG. 5B shows a rectangular shape corresponding to the shape of the light source unit 2, and it can be seen that the image is clearly projected as compared with the state of FIG. 5A. As a result, it can be seen that the center of the LED element 3 and the optical axis of the corresponding collimating lens 6 are closer than in the state of FIG. 5A.

FIG. 5C is a result of measurement after moving the lens holder 23 with respect to the LED board 22 by 0.2 mm in the X direction by further operating the adjustment mechanism from the state of FIG. 5B. Further, FIG. 5D is a result of measurement after moving the lens holder 23 with respect to the LED board 22 by 0.2 mm in the Y direction by further operating the adjustment mechanism from the state of FIG. 5C. .. Compared with the state of FIG. 5B, the position of the center 62 of the image 60 is closer to the center O of the reference region 61 in the state of FIG. 5C, and in the state of FIG. 5D, the center 60 of the image 60 is further referred to as the reference region. It is approaching the center O of 61.

By operating the adjusting mechanism in this way, the light emitted from the plurality of LED elements 3 can be collected at almost one point, and the condensing position thereof can be adjusted. In particular, by moving the condensing position to the central portion of the light incident surface 9a of the rod integrator 9, high-illuminance light can be guided on the light emitting surface 9b of the rod integrator 9.

In the present embodiment, the case where the clamping screw 41 is used as the adjusting mechanism has been described, but the adjusting mechanism is not limited to this configuration. For example, as shown in FIG. 6A, the cam 44 may be used, or the pin 45 may be used. In the configuration of FIG. 6A, the rotation shaft of the cam 44 may be attached to the lens holder 23 or the LED board 22. Further, in the configuration of FIG. 6B, the base portion of the pin 45 may be attached to the lens holder 23 or the LED board 22.

[Another Embodiment]
Hereinafter, another embodiment will be described.

<1> As shown in FIG. 7, the integrator optical system 8 may be composed of the fly-eye lens 10. Also in this case, high-intensity light is focused on the incident surface of the fly-eye lens 10, and high-intensity light is emitted from the fly-eye lens 10. In the other configuration described above, the integrator optical system 8 may be configured by the fly-eye lens 10.

<2> The above-mentioned light source device 1 can be used as a light source for an exposure device or a projector. FIG. 8 is a drawing schematically showing the configuration of an exposure apparatus including the light source apparatus 1.

The exposure apparatus 19 is provided with a projection optical system 15 and a mask 16 after the integrator optical system 8, and is provided with a projection lens 17 as needed. The mask 16 is installed at a position projected by the projection optical system 15, and a photosensitive substrate 18 to be printed on the pattern image of the mask 16 is installed after the mask 16. When light is emitted from the light source unit 2 in this state, the light is condensed by the second optical system 7 and then irradiated to the projection optical system 15 as light having a uniform illuminance distribution by the rod integrator 9. Will be done. The projection optical system 15 projects the pattern image of the mask 16 onto the photosensitive substrate 18 directly or through the projection lens 17.

When the light source device 1 is used in the exposure device 19, an ultraviolet light emitting element is often used as the LED element 3. As described above, when the light emitted from the LED element 3 is ultraviolet light, the image cannot be visually recognized. In such a case, a plate coated with a phosphor is placed on the light incident surface of the integrator optical system 8 (the light incident surface 9a of the rod integrator 9), and the phosphor is excited by ultraviolet light to obtain an image. The relative positional relationship between the LED board 22 and the lens holder 23 may be adjusted by operating an adjustment mechanism (clamping screw 41, etc.) after making the image visible.

<3> In the above-described embodiment, the lens holder 23 can be moved with respect to the LED board 22 in the X direction, the Y direction, and the rotation direction on the XY plane, respectively. However, it may be configured to be movable in at least one of these directions, or may be configured to be movable in yet another direction (for example, a direction orthogonal to the XY plane). Further, the LED board 22 may be configured to be movable with respect to the lens holder 23.

<4> In each of the above-described embodiments, the light source device 1 may be provided with an optical system such as a catadioptric system as appropriate for the purpose of changing the optical path.

1: Light source device 2: Light source unit 3: LED element 5: First optical system 6: Collimating lens 7: Second optical system 7f: Focus of second optical system 8: Integrator optical system 9: Rod integrator 9a: Rod integrator Incident surface 9b: Ejection surface of rod integrator 10: Fly eye lens 11: Optical axis 15: Projection optical system 16: Mask 17: Projection lens 18: Photosensitive substrate 19: Exposure device 22: LED board 23: Lens holder 41: Clan Ping screw 42: Ball plunger 44: Cam 45: Pin 60: Image 61: Reference area 62: Center of image

Claims (9)

A light source unit in which multiple LED elements are arranged, and
A first optical system that includes a plurality of collimating lenses arranged corresponding to each of the plurality of LED elements and collimates the light emitted from the plurality of LED elements of the light source unit.
A second optical system that collects a plurality of lights emitted from the first optical system is provided.
An adjustment mechanism for adjusting the relative positional relationship between the light source unit and the first optical system to at least one of the light source unit and the first optical system to correct the condensing position by the second optical system. A light source device characterized by being equipped with. The plurality of LED elements are arranged on a predetermined plane, and the plurality of LED elements are arranged on a predetermined plane.
The adjustment mechanism according to claim 1, wherein the adjusting mechanism is configured to be able to adjust the relative positional relationship between the light source unit and the first optical system in a direction parallel to the predetermined plane. Light source device. The light source device according to claim 2, wherein the adjusting mechanism is configured so that at least one of the light source unit and the first optical system can be rotated on a plane parallel to the predetermined plane. An LED board containing the light source unit and
A lens holder containing the first optical system and a lens holder are provided.
Any of claims 1 to 3, wherein at least one of the LED board and the lens holder is provided with an adjusting mechanism for adjusting the relative positional relationship between the light source unit and the first optical system. The light source device according to item 1. The integrator optical system whose incident surface is arranged at the focal position of the second optical system is provided.
By adjusting the relative positional relationship between the light source unit and the first optical system, the adjustment mechanism can correct the focusing position of the integrator optical system on the incident surface by the second optical system. The light source device according to claim 4, wherein the light source device is configured. The light source device according to claim 4 or 5, wherein the adjusting mechanism is attached to the LED board. The light source device according to claim 4 or 5, wherein the adjusting mechanism is attached to the lens holder. The light source device according to claim 5, wherein the integrator optical system is composed of a light guide member that guides light incident from the incident surface to an emission surface while repeating reflection on the inner surface. .. The light source device according to claim 5, wherein the integrator optical system is composed of a fly-eye lens in which a plurality of lenses are arranged in a matrix.

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