JP2016103423A - Light source device and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a high efficient connection of coherent light fluxes ejected from a plurality of element light sources into an optical fiber and accomplish an effective cooling for the element light sources.SOLUTION: This light source device comprises a plurality of element light sources for radiating coherent light fluxes; a reflection mirror for shortening a spacing between the coherent light fluxes; a light collection optical element for converting ejected light fluxes into a collective light flux to form a high density light irradiation region; an optical fiber holder; a base block on which the element light sources and reflection mirror, light collective optical element and optical fiber holder are placed and also acting a thermal radiator for cooling the element light sources; and a fluid mechanism of flowing cooling fluid for cooling the base block. A surface on which the element light sources are mounted is formed in a stairs manner and each of the element light sources is placed at any one of the surface stages and there is provided a fluid flow passage to cause the cooling fluid to act on the lower surface of the block and a direction of flow of the cooling fluid may become a direction in height difference at the staircase surfaces at the base block.SELECTED DRAWING: Figure 2

Description

  The present invention, for example, the light emitted from a solid-state light source such as a semiconductor laser, which is preferably used as a light source for an optical device such as a projector or a light source for an exposure device in a light irradiation process in the manufacturing process, The present invention relates to a light source device that is used via an optical fiber, and that can perform desired cooling on each of a plurality of element light sources constituting the light source device using a simple fluid mechanism.

For example, optical devices for image display, such as DLP (TM) projectors and liquid crystal projectors, and exposure devices for photomask transfer, annealing, etc., have so far had high brightness such as xenon lamps and ultra-high pressure mercury lamps. A discharge lamp (HID lamp) or a halogen lamp has been used.
However, the lamps described above have drawbacks such as low conversion efficiency from input power to optical power, that is, large heat loss or short life.
In recent years, solid light sources such as LEDs and semiconductor lasers have attracted attention as alternative light sources that have overcome these drawbacks.
Among them, the LED has a smaller heat loss and a longer life than the discharge lamp, but the emitted light has no directivity like the discharge lamp. However, in applications where only light in a specific direction can be used, there is a problem that the light use efficiency is low.

On the other hand, for semiconductor lasers, as in the case of LEDs, the heat loss is small, the lifetime is long, and the directivity is high, so that only light in a specific direction can be used, such as the projectors and exposure apparatuses described above. Also, there is an advantage that the light use efficiency is high.
In addition, the high directivity makes it possible to perform optical transmission with high efficiency, so it is possible to separate the installation location of the semiconductor laser from the location where the light is used, such as a projector. The degree of freedom can be increased.

However, there is a problem that speckle noise is generated in the semiconductor laser.
Here, the speckle is a coherent light generated by wavelength conversion of laser light from a semiconductor laser or other laser or laser light (using a nonlinear optical phenomenon such as harmonic generation or optical parametric effect). Granular and speckled patterns that inevitably appear when light is projected, especially when used in combination with optical fibers, and the effect becomes noticeable, producing images for viewing like the projectors mentioned above This is a very troublesome phenomenon that significantly deteriorates the image quality in applications where the photomask pattern is precisely exposed on the coating made of photosensitive material, so many improvements have been proposed for a long time. Has been.
For example, using a diffuser plate, fly eye integrator, rod integrator, lens array, beam splitter, multiple reflection element, etc., the light beam from the coherent light source is divided in the cross section perpendicular to the optical axis and superimposed, A phase, polarization state, delay, etc. depending on the position of the cross section perpendicular to the optical axis of the light beam is added, and the split state and the applied state are changed with time by rotating, vibrating, or swinging the optical element. Or mixing light beams from a plurality of coherent light sources having slightly different wavelengths.

Among these devices, the most frequently used means is to use a diffusion plate. However, when this means is used alone, the speckle noise reduction ability increases as the degree of diffusion increases. Since there is a trade-off relationship in which the utilization efficiency is lowered, there are few that reduce speckle noise by relying on the function of the diffuser alone, and most of them use other means in combination as described above.
For example, Japanese Patent Laid-Open No. 51-064325 describes a technique for rotating a ground glass disk as a diffusion plate in a character pattern generator using a laser in order to prevent a decrease in resolution due to speckle. There are a large number of publications that propose similar techniques.
However, as described above, the stronger the degree of diffusion, the higher the speckle noise reduction capability. On the other hand, it is unavoidable that the light use efficiency is reduced. It is strongly desired to establish a speckle noise reduction technology that does not require the use of a strong diffusing plate and that does not require a rotation mechanism, a vibration mechanism, or a high-performance optical element that causes high costs.

For example, Japanese translations of PCT publication No. 2004-503923 describes a technique using a plurality of laser elements that define the relationship between spectral width and center wavelength shift, and Japanese Patent Application Laid-Open No. 2004-146793 discloses a plurality of different wavelengths. A technique relating to an exposure apparatus using light of a semiconductor laser is described.
These technologies are advantageous in that they do not require a rotating mechanism, a vibration mechanism, or a high-performance optical element, but a large number of semiconductor laser elements are prepared in order to achieve this. Therefore, it is necessary to configure a semiconductor laser element set that can realize the desired wavelength distribution, which also increases the cost.

Of course, speckle noise is not a fatal problem in all lighting devices that irradiate light on an object. Depending on the application, there may be some speckle noise. Even if a semiconductor laser is used, if it is not operated while it is sufficiently cooled, an effective cooling mechanism is required to damage it or shorten its life. This is an issue inseparable from mounting technology.
In addition, when the emitted light from a plurality of semiconductor lasers is to be transmitted through a single optical fiber, the diameter of the optical fiber core that is the light transmission path is narrow, and the incident angle of light that can be transmitted by the optical fiber is limited. In other words, since there is an upper limit on the NA, an effective optical element arrangement in the optical system for realizing highly efficient coupling to the optical fiber is required, which is also inseparable from the semiconductor laser mounting technology in the apparatus. It is a difficult task.

As a proposal aiming at effective cooling of a plurality of semiconductor lasers just described and high-efficiency coupling of emitted light of a plurality of semiconductor lasers to an optical fiber, for example, Japanese Patent Application Laid-Open No. 2014-175626 has a stepped shape. By installing the semiconductor laser array at each stage of the heat sink, the beams from the plurality of semiconductor laser arrays can be made into a single combined light beam with as close as possible beam spacing, and a condensing lens Describes a light source device that can be coupled to a single optical fiber with high efficiency.
However, since this technique mounts a plurality of small semiconductor laser chips alone on a heat sink, it cannot be applied to a large semiconductor laser such as a form housed in a can-type envelope. It was.

JP-A-51-064325 Special table 2004-503923 JP 2004-146793 A JP 2014-175626 A

  A problem to be solved by the present invention is a light source device that achieves efficient cooling of an element light source by coupling coherent light beams from a plurality of element light sources such as semiconductor lasers to an optical fiber with high efficiency. It is to provide.

The light source device of the first invention in the present invention includes a plurality of element light sources (U1, U2,...) That emit coherent light beams (F1, F2,...) That form a distant image,
Correspondence is determined for each of the element light sources (U1, U2,...), And only the coherent light beams (F1, F2,...) From the corresponding element light sources (U1, U2,...) Are reflected, Reflectors (R1, R2,...) For shortening the interval between the coherent light beams (F1, F2,...);
The coherent light beams (F1, F2,...) Reflected by the reflecting mirrors (R1, R2,...) Are incident, and the incident light beams are converted into a focused light beam (Fg) to be irradiated with a high-density light irradiation region (Ag). A condensing optical element (Eg) for forming
An optical fiber holder (Er) for holding the optical fiber (Ef) so that the end face of the core is positioned in the vicinity of the high-density light irradiation region (Ag);
The element light sources (U1, U2,...) And the reflecting mirrors (R1, R2,...), The condensing optical element (Eg), and the optical fiber holder (Er) are placed on the optical fiber holder (Er) and fixed thereon. A base (B) that also serves as a heat radiator for cooling the element light sources (U1, U2,...);
A fluid mechanism (Cs) for flowing a cooling fluid for cooling the base (B);
A light source device comprising:
When the surface (Su) on which the element light sources (U1, U2,...) Of the base (B) are placed is viewed as an upper side, the surface (Su) is formed in a step shape and the element light sources ( Each of U1, U2,...) Is placed on one of the steps of the surface (Su),
A fluid flow path (Cr) is provided so that the cooling fluid of the fluid mechanism (Cs) acts on the lower surface (Sc) of the base (B), and the flow direction of the cooling fluid is: It is the direction of the height difference of the stepped surface (Su) in the base (B).

  The light source device according to a second aspect of the present invention is characterized in that the flow direction of the cooling fluid is a direction from the higher side to the lower side of the stepped surface (Su) of the base (B). To do.

  The light source device according to a third aspect of the present invention is characterized in that the flow direction of the cooling fluid is a direction from a lower side to a higher side of the stepped surface (Su) of the base (B). To do.

  A light source device according to a fourth aspect of the present invention includes at least two systems of a first fluid mechanism (Cs1) and a second fluid mechanism (Cs2) as the fluid mechanism, and the first fluid mechanism. The direction of the cooling fluid flowing through (Cs1) is different from the direction of the cooling fluid flowing through the second fluid mechanism (Cs2).

  A light source device according to a fifth aspect of the present invention includes at least two systems of a first fluid mechanism (Cs1) and a second fluid mechanism (Cs2) as the fluid mechanism, and the first fluid mechanism. The direction and flow rate of the cooling fluid that flows through (Cs1) and the direction and flow rate of the cooling fluid that flows through the second fluid mechanism (Cs2) can be independently controlled.

  In the light source device according to a sixth aspect of the present invention, the lower surface (Sc) of the base (B) includes a protruding structure (Cb) for increasing the surface area on which the cooling fluid acts. In addition, the amount of increase in surface area due to the protruding structure (Cb) varies depending on the direction of the height difference of the stepped surface (Su) in the base (B). .

  A lighting device according to a seventh aspect of the present invention is a light source device (Uo) according to the first aspect of the present invention and a drive circuit (P1, P2, which feeds power to the light emitting elements of the element light sources (U1, U2,...). ...), a fluid mechanism drive control circuit (Uc) for driving the fluid mechanism (Cs), and the optical fiber (Ef) having one end held by the optical fiber holder (Er). The object (Wk) is irradiated with an irradiation light beam (Fw) emitted from the other end of the fiber (Ef).

  It is possible to provide a light source device that achieves efficient cooling of an element light source by coupling coherent light beams from a plurality of element light sources such as semiconductor lasers to an optical fiber with high efficiency.

The schematic diagram which simplifies and shows a part of light source device of this invention is represented. The schematic diagram which simplifies and shows the light source device of this invention is represented. The schematic diagram which simplifies and shows a part of light source device of this invention is represented. The schematic diagram which simplifies and shows one form of the one part of the Example of the light source device of this invention is represented. The schematic diagram which simplifies and shows one form of the one part of the Example of the light source device of this invention is represented. The schematic diagram which simplifies and shows one form of the one part of the Example of the light source device of this invention is represented. The conceptual diagram which simplifies and shows one form of the one part of the Example of the light source device of this invention is represented. The figure which simplifies and shows one form of the Example of the light source device of this invention is represented.

First, the form for implementing this invention is demonstrated using FIG. 1 which is a schematic diagram which simplifies and shows a part of light source device of this invention.
Each of the element light sources (U1, U2,...) Includes a light emitting element such as a semiconductor laser and a collimator optical element (for example, a collimator lens) that converts the emitted light into a light beam that forms a distant image. A coherent light beam (F1, F2,...) Close to a light beam or a parallel light beam is output.

Each of the element light sources (U1, U2,...) Is installed on a base (B), and a surface (Su) on the base (B) on which the element light sources (U1, U2,...) Are installed. ) Is formed in a stepped shape, and the element light sources (U1, U2,...) Are placed on any of the steps of the surface (Su), and the surface (Su) is provided by means such as screwing (not shown). ) And the heat generated in the element light sources (U1, U2,...) Is discharged to the base (B).
Each of the element light sources (U1, U2,...) Is associated with a reflecting mirror (R1, R2,...) Responsible for reflecting the coherent light flux (F1, F2,...) From the element light source. The reflecting mirrors (R1, R2,...) Are arranged so as to reflect only the coherent light beams (F1, F2,...) From the corresponding element light sources (U1, U2,...).

For example, the element light source (U1) and the reflecting mirror (R1) are arranged on the uppermost stage, and the element light source (U2) and the reflecting mirror (R2) are arranged on the second stage from the top, The reflecting mirror (R1) reflects only the coherent light beam (F1) and passes just above the lower reflecting mirror, and the reflecting mirror (R2) reflects only the coherent light beam (F2). Then, the element light source and the reflecting mirror are allowed to function such that the light passes through the reflecting mirror in the lower stage, and the same is applied to the lower stage, so that the coherent light beams (F1, F2,... ) The mutual interval can be shortened.
In the figure, the same identification symbol is assigned to the light beam produced by reflecting the coherent light beam (F1, F2,...) Or the like by a reflecting mirror.

The coherent light beams (F1, F2,...) Reflected by the reflecting mirrors (R1, R2,...) And shortened from each other are incident on a condensing optical element (Eg) composed of a lens or the like and converged. It is converted into (Fg) to form a high-density light irradiation region (Ag).
By holding one end of the optical fiber (Ef) so that the end face of the core is positioned in the vicinity of the high-density light irradiation region (Ag), the coherent luminous flux (F1, F2,...) Is converted into the optical fiber (Ef). It is possible to output a light beam from the other end of the optical fiber (Ef).

The holding of the condensing optical element (Eg) and the optical fiber (Ef) will be described with reference to FIG. 2 which is a schematic diagram showing the light source device of the present invention in a simplified manner.
In the figure, the optical fiber (Ef) itself is held by a ferrule (Eh) together with a protective coating (Es), and a fixing nut (Ehn) is added to form an optical fiber connector plug (Ep). Eh) is held by an optical fiber holder (Er) as an optical fiber connector receptacle, and the optical fiber holder (Er) is fixed to the base (B) via the optical fiber connector receptacle holder (He). To do.
The optical fiber holder (Er) has a male screw cut, and the ferrule (Eh) is made to be the optical fiber holder (Er) by tightening the fixing nut (Ehn) having a female screw cut. Is assumed to be fixed.

The light source device of the present invention is further provided with a fluid mechanism (Cs) for cooling the base (B), which is the element light source (U1, U2,...) In the base (B). When the surface (Su) on which the substrate is placed is viewed as being on the upper side, the fluid flow path (Cr) is formed on the surface (Sc) so that the cooling fluid acts on the lower surface (Sc) of the base (B). It is configured to be in contact with Sc).
In the figure, it is assumed that the cooling fluid is air driven by a fan (Cf).
The flow direction of the cooling fluid is set to the direction of the height difference of the stepped surface (Su) in the base (B), that is, the arrow (D1) or the arrow (D2).

Here, the meaning and importance of shortening the interval between the coherent light beams (F1, F2,...) And making them dense will be supplemented.
If, for example, it is assumed that all the element light sources (U1, U2,...) Are simply arranged two-dimensionally without considering the shortening of the interval, the coherent luminous flux ( The two-dimensional spacing between F1, F2,... Is very sparse.
In order to condense such a sparse coherent light beam (F1, F2,...) On the core of the optical fiber (Ef), the condensing optical element (Eg) has a larger diameter than the dense case. However, this itself is disadvantageous because it increases the size and cost of the light source device.

Even if the inconvenience is ignored, in order to keep the angle of the focused light beam (Fg) within the NA of the optical fiber, the focal length of the condensing optical element (Eg) must be increased. Spots formed on the end face of the optical fiber (Ef) by each of the light beams (F1, F2,...) Have a large area due to the influence of diffraction, and are also astigmatism spots peculiar to the semiconductor laser. Since the asymmetric shape is also enlarged, depending on conditions, there is a risk that it will not fit within the core diameter of the optical fiber.
Further, in each direction of the coherent light beams (F1, F2,...), The amount of deviation of the spot position on the end face of the optical fiber (Ef) becomes large when there is an error instead of being strictly parallel to the optical axis. Therefore, high accuracy is required to adjust the angle of the coherent light beams (F1, F2,...).
Incidentally, the area of the spot, the astigmatism asymmetric shape, and the degree of the phenomenon that the spot position deviation amount increases are proportional to the focal length of the condensing optical element (Eg).
Therefore, it can be understood that it is extremely important to make the two-dimensional spacing between the coherent light beams (F1, F2,...) As close as possible.

In the case where the flow direction of the cooling fluid in the fluid mechanism (Cs) is the direction from the higher side to the lower side of the stepped surface (Su) in the base (B), the base The thickest part of (B), that is, the part with the lowest cooling efficiency becomes the most upstream of the fluid flow path (Cr), and the cold wind acts on the contrary, and the thinnest part of the base (B), that is, the cooling. Since the portion with the highest efficiency is the most downstream of the fluid flow path (Cr) and the warm wind acts, the cooling efficiency for the entire element light source (U1, U2,...) Is made uniform, and therefore the element light source Effective cooling can be realized.
As a result, if the input power to each of the element light sources (U1, U2,...) Is the same, the temperatures of the light emitting elements of the element light sources (U1, U2,. It becomes possible to maintain an ideal state.

On the other hand, when the flow direction of the cooling fluid is the direction from the lower side to the higher side of the stepped surface (Su) of the base (B), the most of the base (B) The thin part, that is, the part with the best cooling efficiency is the most upstream of the fluid flow path (Cr), and the cold wind acts on the contrary. The thickest part of the base (B), that is, the part with the worst cooling efficiency. Is the most downstream of the fluid flow path (Cr) and the warm wind acts, so that the cooling efficiency of the entire element light source (U1, U2,...) Is made non-uniform, and therefore effective cooling of the element light source is achieved. Can be realized.
As a result, if the input power to each of the element light sources (U1, U2,...) Is the same, the temperature of the element light source (U1) mounted at the thickest part of the base (B) becomes the highest. The temperature of the element light source mounted at the thinnest part of the base (B) is lowest, and the temperature of the light emitting elements of the element light sources (U1, U2,...) Is intentionally made uneven. be able to.

In many semiconductor lasers, there is a characteristic that the emission wavelength depends on temperature, and this characteristic is usually regarded as a defect, but in the present invention, this characteristic is effectively used.
Assuming that the light emitting elements of the element light sources (U1, U2,...) Are semiconductor lasers, the temperatures of the light emitting elements are unevenly distributed in this manner and appropriately distributed in a specific temperature range, so that their emission wavelengths Is distributed in a specific range, and a state in which light beams from a plurality of coherent light sources having slightly different wavelengths are mixed is realized, which is effective in reducing speckle noise.

  In the case of the fluid mechanism just described, whether the cooling fluid flows in any direction of the height difference of the stepped surface (Su) in the base (B), the element is used for safe driving of the light emitting element. The required flow rate required by the whole of the light sources (U1, U2,...) Must be flowed, and once the flow rate is determined, the temperature of each light emitting element of the element light sources (U1, U2,. (Temperature difference) is determined, and the degree of freedom for providing a temperature distribution range to each light emitting element is insufficient.

Therefore, improvement of the cooling fluid mechanism for compensating for the lack of flexibility will be described with reference to FIG. 3 which is a schematic diagram showing a part of the light source device of the present invention in a simplified manner.
(B) of this figure is the figure which looked at the fluid mechanism from the direction in which the lower surface (Sc) of the base (B) is the front, and (a) is the flow of cooling fluid, or It is the figure which looked at the fluid mechanism along the direction which flows.
In addition, in this figure, description of the said element light sources (U1, U2, ...) etc. which are mounted on the said surface (Su) is abbreviate | omitted.

The light source device shown in the figure includes two independent fluid mechanisms, a first fluid mechanism (Cs1) and a second fluid mechanism (Cs2).
In the first fluid mechanism (Cs1), the cooling fluid driven by the fan (Cf1) flows through the fluid flow path (Cr1) defined by the fluid guide walls (Cg1, Cg2), and the second fluid mechanism In (Cs2), the fluid flow path (Cr2) defined by the fluid guide walls (Cg2, Cg3) is configured such that the cooling fluid driven by the fan (Cf2) flows.
Incidentally, in order to improve the thermal coupling between the base (B) and the fluid flow path (Cr1, Cr2) and improve the cooling efficiency, the surface (Sc) has a surface area on which the cooling fluid acts. A projecting structure (Cb) to be increased, that is, a radiation fin is provided.

  Then, for example, the first fluid mechanism (Cs1) is set so that the direction of the cooling fluid flowing through the first fluid mechanism (Cs1) is different from the direction of the cooling fluid flowing through the second fluid mechanism (Cs2). ), The flow direction of the cooling fluid is a direction from the higher side to the lower side of the stepped surface (Su) of the base (B), and the second fluid mechanism (Cs2) The functions of the fans (Cf1, Cf2) are set so that the fluid flow direction is a direction from the lower side to the higher side of the stepped surface (Su) of the base (B).

  With this configuration, the cooling capacity of the entire fluid mechanism is defined by the sum of the flow rates of the cooling fluids of the first and second fluid mechanisms (Cs1, Cs2), and the element light sources (U1, U2, ...) Since the temperature distribution of each light emitting element is defined by the balance of the flow rate of the cooling fluid of the first and second fluid mechanisms (Cs1, Cs2), the above-described lack of freedom is compensated. be able to.

Further, according to the situation of the light source device at that time, that is, according to the necessity of the speckle noise reduction function, the distribution range of the temperature of the light emitting elements of each of the element light sources (U1, U2,...) The direction and flow rate of the cooling fluid flowing through the first fluid mechanism (Cs1) and the direction and flow rate of the cooling fluid flowing through the second fluid mechanism (Cs2) in the configuration of the fluid mechanism described above, respectively. Independently, it is preferable to enable dynamic control.
At that time, the first fluid mechanism (Cs1) and the second fluid mechanism (Cs2) can be controlled to flow in the same direction, or the first fluid mechanism (Cs1) and the second fluid mechanism (Cs1) can be controlled. It is also possible to control so that the ratio of the respective flow rates is set in multiple steps or substantially continuously after flowing in a direction different from that of the fluid mechanism (Cs2).

In this case, these dynamic controls can be achieved by dynamically controlling the input power to the fans (Cf1, Cf2).
In addition, a temperature sensor is provided for each of the element light sources (U1, U2,...) So that the temperature of each light emitting element can be measured, and the detected temperature value of each temperature sensor has an intended distribution. It is more preferable to feedback control the input power to (Cf1, Cf2).

With respect to the protruding structure (Cb) described in FIG. 3, the fluid mechanism functions effectively for cooling the base (B) in both cases where there is only one system and when there are a plurality of systems. When this is provided, the amount of increase in surface area due to the protruding structure (Cb) may be changed depending on the direction of the level difference of the stepped surface (Su) in the base (B). .
At this time, if the increase in surface area due to the protruding structure (Cb) is large at the thick part of the base (B) and small at the thin part, the element light sources (U1, U2,...) Each element light source (U1, U2,...) Can be reduced by narrowing the temperature distribution range of each light emitting element, and conversely, by reducing the temperature at the thick part of the base (B) and increasing it at the thin part. Since there is an effect of widening the temperature distribution range of the light emitting element, the shape of the protruding structure (Cb) may be determined according to the effect to be obtained.
In the case where the fluid mechanism is as shown in FIG. 3 having a plurality of systems, the first fluid mechanism (Cs1) and the second fluid mechanism (Cs2) are caused by the protruding structure (Cb). You may make it the way of a change when the increase amount of a surface area changes depending on the direction of the height difference of the step-like surface (Su) in the said base (B).

Some supplements will be described for the embodiments of the light source device of the present invention described so far.
When the coherent light beams (F1, F2,...) Emitted from the element light sources (U1, U2,...) Are parallel light beams that form an infinite image, they are input to the condensing optical element (Eg). If the principal rays of the coherent light beams (F1, F2,...) Are made parallel to the axis of the condensing optical element (Eg), the focused light beam (Fg) is condensed. All the light beams form an image at the focal point of the optical element (Eg) to form the high-density light irradiation region (Ag). In this case, the power density of the high-density light irradiation region (Ag) is high. Therefore, the end face of the optical fiber (Ef) may be broken.

In such a case, even if each of the coherent light beams (F1, F2,...) Emitted from the element light sources (U1, U2,...) Is a parallel light beam forming an infinite image, If the principal rays of the coherent light beams (F1, F2,...) Input to the condensing optical element (Eg) are focused on a certain point on the axis of the condensing optical element (Eg), this Since the point is the entrance pupil of the condensing optical element (Eg), the focused light beam (Fg) forms an exit pupil before the focal point of the condensing optical element (Eg), and this is irradiated with the high-density light. If the region (Ag) is formed on the core end face of the optical fiber (Ef), the problem that the power density of the high-density light irradiation region (Ag) becomes too high can be avoided.
Alternatively, each of the coherent luminous fluxes (F1, F2,...) Emitted from the element light sources (U1, U2,...) Forms an image at a distance but a finite distance, for example, a negative distance, not infinity. After adjusting the collimator optical element of the element light source (U1, U2,...) So as to be a divergent light beam that is nearly parallel, the coherent light beam (F1) input to the condensing optical element (Eg) , F2,...) If the principal rays are parallel to the axis of the converging optical element (Eg), that is, telecentric, the focused light beam (Fg) is converted into the converging optical element (Eg). ) Is formed on the core end face of the optical fiber (Ef) as the high-density light irradiation region (Ag), and the power density of the high-density light irradiation region (Ag) is as follows. High It is possible to avoid the now too problem.

In addition to the types of light emitting elements of the element light sources (U1, U2,...), In addition to the semiconductor laser described above, for example, non-linear optical phenomena such as harmonic generation and optical parametric effects are used for the emitted light of the semiconductor laser. Then, a light source for wavelength conversion may be used.
Further, in FIG. 1, the reflecting mirrors (R1, R2,...) Are drawn like a prism, but this is performed on a predetermined surface of the prism made of glass with a required dimensional accuracy. It is assumed that a dielectric multi-layer coating corresponding to the wavelength is applied to form a high-reflectivity surface, and is adhesively fixed to the base (B). For example, a mirror holder that can finely adjust the rotation and tilt angle A movable mirror equipped with a plane mirror may be used.
Furthermore, in FIG. 2, although the example of the said optical fiber holder (Er) which hold | maintains the said optical fiber (Ef) indirectly through the said ferrule (Eh) was described, the said optical fiber holder (Er) was described. ) May be configured to directly hold the optical fiber (Ef) itself without passing through the ferrule (Eh).
In addition, although the said optical fiber connector receptacle holder (He) has drawn what has the function of the holder with respect to the said condensing optical element (Eg), you may make it provide and hold | maintain another holder.
Moreover, although the example which uses an air-cooling type about the said fluid mechanism (Cs) was described, the cooling method by other types of fluid mechanisms, such as a water cooling type, may be sufficient, for example.

It has been described that the surface (Su) on which the element light sources (U1, U2,...) Are placed is formed in a staircase shape. Here, the staircase shape refers to the surface of each step having a single plane. It is not meant to be limited to what is made.
For example, in FIG. 1 and the like, the element light source (U1) and the reflecting mirror (R1) are on the uppermost stage forming a single plane, and the element light source (U2) and the reflecting mirror (R2) are single. The reflecting mirrors (R1, R2,...) Are assumed to be short, for example, and instead of the surface (the surface) at the position where they are placed, Su) is raised in a trapezoidal shape, so that the required height is realized as the height of the uppermost part of the reflecting mirrors (R1, R2,...). As a result, the surface of each step is single. You may comprise so that it may not be a plane.
Alternatively, the back surface of the element light source (U1, U2,...), That is, the contact surface with the surface (Su) in the element light source (U1, U2,...) Is drawn as a simple plane. When the back surface of the light source (U1, U2,...) Is a surface having a complicated shape, for example, having unevenness, the surface (Su) exhibits a complementary shape (opposite shape) at the position where they are placed. Therefore, good thermal contact may be realized, and as a result, the surface of each step may not be a single plane.

First, the object on which the cooling fluid of the fluid mechanism (Cs) acts is viewed so that the surface (Su) on the base (B) on which the element light sources (U1, U2,...) Are placed is on the upper side. In this case, the lower surface (Sc) of the base (B) has been described. However, this surface means that the surface ( You may prescribe | regulate by the phrase called the surface which opposes Su).
However, the reason for not doing so is because the surface (Su) is not a single surface but a complex surface composed of a plurality of surfaces, and feared that the word “facing” could cause confusion. is there.
Therefore, in other words, the target to which the cooling fluid of the fluid mechanism (Cs) acts is a local surface that is visible due to the stepped structure or irregularities of the surface (Su). In other words, it is a surface facing the surface (Su) when viewed as a whole.
Further, at this time, it is natural that the opposing surfaces are not defined to be exactly parallel planes from the purpose of the present invention.

Examples of the light source device of the present invention will be described below.
FIG. 4 is a schematic diagram showing a simplified form of a part of the embodiment of the light source device of the present invention.
FIG. 1 shows that one of the element light sources (U1, U2,...) Is arranged on one step of the stepped surface (Su), but in the case of the light source device of FIG. The element light sources (U1, U1 ′) are arranged on the second stage, the element light sources (U2, U2 ′) are arranged on the second stage from the top, and the other stages are similarly arranged.
However, in this case, each of the reflecting mirrors (R1, R2,...) Collects the coherent light beam (F1, F1 ′) and the coherent light beam (F2, F2 ′) from the opposing direction, respectively, and collects optical elements (not shown). ) Are provided so as to be reflected in the direction of), but naturally, this may be divided into two parts having one reflective surface.
Therefore, when each step of the stepped surface (Su) is configured by this arrangement method, twice as many coherent light beams as those in FIG. 1 can be incident on the condensing optical element.

On the other hand, the light source device shown in FIG. 5, which is a schematic diagram showing a form of a part of a part of the embodiment of the light source device of the present invention, is not in the opposite direction as shown in FIG. 4 but in the same direction. A plurality of element light sources (U1, U1 ′, U1 ″) that emit coherent luminous fluxes (F1, F1 ′, F1 ″) that are directed are arranged in one stage.
This figure shows only the arrangement example of the uppermost step of the stepped surface (Su), but the second step from the top and subsequent steps may be arranged in the same manner. The number of element light sources arranged every time may not be the same.
Further, by combining this arrangement method and the arrangement method described in FIG. 4, for example, the element light sources facing each of the element light sources (U1, U1 ′, U1 ″) can be arranged. .

Next, the form for implementing this invention is demonstrated using FIG. 6 which is a figure which simplifies and shows one form of the Example of the light source device of this invention.
(A) of this figure shows the internal structural example about one of the said element light sources (U1, U2, ...), The assembly structure for mounting | wearing a light emitting element with a collimator optical element, ( b) represents a state in which the lens holder (Hz1, Hz2,...) to which the collimator (Ec) is fixed is attached to the light emitting element, and a state in which the light emitting element is mounted on the heat sink (Hs). For example, a part of an integrated light source in which a plurality of element light sources can be used as the element light sources (U1, U1 ′,...) Shown in FIG.

The light-emitting element of this figure is covered with an envelope composed of metal case portions (My1, My2,...) And a light transmission window portion (not shown), and also includes energization terminals (TyA, TyB). In general, it has a structure called a can type.
In order to emit a light beam that generates a distant image point in a direction perpendicular to the structural reference plane (Pz1, Pz2,...) Of the metal case portion (My1, My2,...) Of the light emitting element. In order to install the collimator (Ec), the collimator (Ec) is first fixed to the lens mount (Hz1 ′, Hz2 ′,. The lens mount (Hz1 ′, Hz2 ′,...) Is fixed to the lens holder (Hz1, Hz2,...) Fixed to the light emitting element by means of, for example, adhesion. The collimator (Ec) is fixed to Hz1, Hz2,.
That is, when the collimator (Ec) is fixed to the lens holder (Hz1, Hz2,...), The lens mount (Hz1 ′, Hz2 ′,...) Is interposed between them instead of directly fixing. .

By adopting such a structure, if the collimator (Ec) is fixed to the lens mount (Hz1 ′, Hz2 ′,...) So that there is no eccentricity, it is fixed to the light emitting element. The lens holder (Hz1, Hz2,...) Is caused to emit light by causing a current to flow through the light emitting element, and a light beam that has passed through the collimator (Ec) is in a predetermined collimated state (an image conjugate with the active region of the light emitting element). While performing optical observation so that an image is formed at a predetermined position), a position in the optical axis direction (and a position in a plane perpendicular to the optical axis direction) is driven to a predetermined position, and the lens mount (Hz1 ′, Hz2 ′,... ) Can be fixed to the lens holder (Hz1, Hz2,...).
FIG. 6B shows an adhesive potting (HpA) for fixing the collimator (Ec) and an adhesive potting (HpB) for fixing the lens mounts (Hz1 ′, Hz2 ′,...). However, it is not necessary to apply to the entire periphery of the collimator (Ec) or the lens mount (Hz1 ′, Hz2 ′,...), And it may be from two to three places around the periphery.

As described above, each of the element light sources (U1, U2,...) Is configured, and these are integrated and mounted on the common heat sink (Hs), thereby configuring one of the integrated light sources. be able to.
When the heat sink (Hs) is made of a metal material such as aluminum, the lens holder (Hz1, Hz2,...) That is interposed between the heat sink (Hs) and the metal case (My1, My2,...) When it is necessary to be an insulating member, it is made of a material such as ceramic having good thermal conductivity.

As the element light source in the light source device of the present invention, a semiconductor laser array device can be used in addition to the discrete type semiconductor laser light source shown in FIG. 6, and this is part of the embodiment of the light source device of the present invention. 7 will be described with reference to FIG. 7, which is a conceptual diagram showing a simplified form.
As shown in FIG. 4A, semiconductor laser active regions (As, As ′,...) Are arranged in a line on the end face of the semiconductor laser array device (LDA), and each of the semiconductor laser active regions (As , As ′,...) Emits divergent light.
Regardless of whether it is a discrete type or an array type, the divergence angle of the radiated light beam of an edge-emitting semiconductor laser increases due to the effect of diffraction, and the divergence angle in the direction perpendicular to the substrate surface (of the semiconductor chip of the semiconductor laser) As shown in the peripheral rays (Lms1A, Lms2A), there is a feature that the bottom surface (CiA) of the cone that is particularly large, that is, the radiation angle region, becomes a significant ellipse instead of a circle.

A collimator lens is used to convert this radiated light beam into a parallel beam, but it is necessary to use a short focal length in accordance with a component in a direction perpendicular to the substrate surface having a large divergence angle.
Even if such a collimator lens is used, in the case of a discrete type semiconductor laser, there is no major problem as long as the beam is flat, but in the case of an array type semiconductor laser, the semiconductor laser active region ( When all the radiated light fluxes of As, As ′,... Are converted into parallel beams by one collimator lens, the main length of each of the semiconductor laser active regions (As, As ′,...) Is reduced because the focal length is short. The problem arises that the rays have a large angle with each other.

Therefore, it is possible to use a radiation angle correction lens array (Ey) as shown in FIG.
The radiation angle correction lens array (Ey) individually collimates each of the radiation beams from the semiconductor laser active region (As, As ′,...), And is in a direction perpendicular to the substrate surface. In order to solve the problem of a large divergence angle, each refracting surface of the radiation angle correcting lens array (Ey) is not a spherical surface but has a radius of curvature different in a direction parallel to a direction perpendicular to the substrate surface, for example, a toric surface. To do.
This reduces the divergence angle in the direction parallel to the substrate surface, as in the case of the peripheral rays (Lms1, Lms2), and further reduces the divergence angle in the direction perpendicular to the substrate surface. The divergence angle in the direction parallel to and perpendicular to the substrate surface is made the same level.

  Since the chief rays (Lps) from the respective semiconductor laser active regions (As, As ′,...) Are parallel to each other, the beam train is compact and includes the radiation angle correction lens array (Ey) shown in FIG. The semiconductor laser array device (LDA) is preferably used as an integrated light source that replaces the element light sources (U1, U1 ′,...) Shown in FIG.

  Instead of realizing the toric surface, a curvature in a direction perpendicular to the substrate surface, a cylindrical lens common to the semiconductor laser active region (As, As ′,...), And a curvature in a direction parallel to the substrate surface are provided. And an array of individual cylindrical lenses in each of the semiconductor laser active regions (As, As ′,...), And the function similar to that of the radiation angle correction lens array (Ey) can be achieved by the combination thereof. Can be realized.

Next, an illuminating device constructed by mounting the light source device of the present invention will be described with reference to FIG. 8 which is a diagram showing a simplified form of one embodiment of the light source device of the present invention.
The main body of the illuminating device of the present invention includes a drive circuit (P1, P2,...) That supplies power to the light emitting elements of the element light sources (U1, U2,...) Of the light source device (Uo) of the present invention, and a fluid mechanism (Cs). ) And a fluid mechanism drive control circuit (Uc) for driving the fan (Cf), and an integrated control circuit (not shown). The drive circuit (P1, P2,...) And the fluid mechanism drive The control circuit (Uc) is controlled by the integrated control circuit.
One end of the optical fiber (Ef) is configured as an optical fiber connector plug (Ep), which is held by an optical fiber holder (Er), and the other end of the optical fiber (Ef) is also an optical fiber holder. (Epw), which is held by the optical fiber holder (Erw) of the irradiation optical system (Uw).

The emitted light from the element light sources (U1, U2,...) Is incident on one end of the optical fiber (Ef), propagates through the optical fiber (Ef), and the optical fiber (Ef). Is irradiated from the other end of the laser beam, converted into an irradiation light beam (Fw) having a small divergence angle by a collimator (Ec), and then irradiated onto the object (Wk).
In addition, the kind of light emitting element of each of the element light sources (U1, U2,...) Is selected so that the light emission wavelength is an optimum wavelength according to the purpose of light irradiation to the object (Wk). .
For example, infrared is selected for heating, ultraviolet is used for curing organic materials, and ultraviolet is used for photosensitivity. For example, an appropriate material having a visible wavelength suitable for the sensitivity of the photosensitive material is selected.

The integrated control circuit determines the polarity of the fan (Cf) according to the operation mode of the lighting device.
Specifically, when the operation mode is the uniform cooling mode of the light emitting element, the flow direction of the cooling fluid is a direction from the higher side to the lower side of the stepped surface (Su) in the base (B). When the operation mode is the speckle noise reduction mode, the flow direction of the cooling fluid is a polarity in a direction from the lower side to the higher side of the stepped surface (Su) of the base (B). To do.
Each of the element light sources (U1, U2,...) Includes a temperature sensor (not shown) so that the integrated control circuit can acquire the detected temperature value of each temperature sensor. The circuit controls the input power to the fan (Cf) so that the highest value among all the detected temperature values becomes an intended value.

As the light source device of the present invention, three types, one emitting red, one emitting green, and one emitting blue, are prepared, and an illumination device that emits three primary colors of R, G, B (red, green, blue) is configured. Using this, for example, a projector can be realized.
In this case, for example, light is output from the optical fiber separately for each of R, G, and B, and each of the two-dimensional light modulation elements of R, G, and B is illuminated via a light uniformizing means such as a rod integrator. What is necessary is just to comprise so that each image of R, G, B produced | generated by dimension modulation may be superimposed, and an image may be projected on a screen via a projection lens.
Alternatively, by using a portion other than the light source of a projector using a xenon discharge lamp or a mercury lamp as a light source, the light flux from the illumination device emitting the three primary colors R, G, and B is substituted for the light flux by the discharge lamp. The projector may be realized by inputting as a white light beam.
In application to such a projector, it is preferable to select the speckle noise reduction mode as the operation mode described above.

  The present invention relates to a light source for a solid-state light source such as a semiconductor laser, which is preferably used as a light source for an optical device such as a projector or a light source for an exposure device in a light irradiation process in a manufacturing process. The light source device can be used in an industry that designs and manufactures a light source device that can provide desired cooling to each of a plurality of element light sources constituting the light source device using a simple fluid mechanism. is there.

Ag High-density light irradiation region As Semiconductor laser active region As ′ Semiconductor laser active region B Base Cb Projection structure Cf Fan Cf1 Fan Cf2 Fan Cg1 Fluid guide wall Cg2 Fluid guide wall Cg3 Fluid guide wall CiA Bottom surface Cr Fluid channel Cr1 Fluid flow Path Cr2 Fluid channel Cs Fluid mechanism Cs1 Fluid mechanism Cs2 Fluid mechanism D1 Arrow D2 Arrow Ec Collimator Ef Optical fiber Eg Condensing optical element Eh Ferrule Ehn Fixed nut Ep Optical fiber connector plug Epw Optical fiber holder Er Optical fiber holder Erw Light Fiber holder Es Protective coating Ey Radiation angle correction lens array F1 Coherent light beam F1 ′ Coherent light beam F1 ”Coherent light beam F2 Coherent light beam F2 ′ Coherent light beam Fg Focused light beam Fw Irradiation light beam He Optical fiber connector receptacle Tackle holder HpA Adhesive potting HpB Adhesive potting Hs Heat sink Hz1 Lens holder Hz1 ′ Lens mount Hz2 Lens holder Hz2 ′ Lens mount LDA Semiconductor laser array device Lms1 Peripheral light Lms1A Peripheral light Lms2 Peripheral light Lms2A Peripheral light Lps Main light My1 Metal case part My2 Metal Case P1 Drive Circuit P2 Drive Circuit Pz1 Reference Surface Pz2 Reference Surface R1 Reflector R2 Reflector Sc Surface Su Surface TyA Energizing Terminal TyB Energizing Terminal U1 Element Light Source U1 'Element Light Source U1 "Element Light Source U2 Element Light Source U2' Element Light source Uc Fluid mechanism drive control circuit Uo Light source device Uw Irradiation optical system Wk Object

Claims (7)

A plurality of element light sources (U1, U2,...) That emit coherent light beams (F1, F2,...) That form a distant image;
Correspondence is determined for each of the element light sources (U1, U2,...), And only the coherent light beams (F1, F2,...) From the corresponding element light sources (U1, U2,...) Are reflected, Reflectors (R1, R2,...) For shortening the interval between the coherent light beams (F1, F2,...);
The coherent light beams (F1, F2,...) Reflected by the reflecting mirrors (R1, R2,...) Are incident, and the incident light beams are converted into a focused light beam (Fg) to be irradiated with a high-density light irradiation region (Ag). A condensing optical element (Eg) for forming
An optical fiber holder (Er) for holding the optical fiber (Ef) so that the end face of the core is positioned in the vicinity of the high-density light irradiation region (Ag);
The element light sources (U1, U2,...) And the reflecting mirrors (R1, R2,...), The condensing optical element (Eg), and the optical fiber holder (Er) are placed on the optical fiber holder (Er) and fixed thereon. A base (B) that also serves as a heat radiator for cooling the element light sources (U1, U2,...);
A fluid mechanism (Cs) for flowing a cooling fluid for cooling the base (B);
A light source device comprising:
When the surface (Su) on which the element light sources (U1, U2,...) Of the base (B) are placed is viewed as an upper side, the surface (Su) is formed in a step shape and the element light sources ( Each of U1, U2,...) Is placed on one of the steps of the surface (Su),
A fluid flow path (Cr) is provided so that the cooling fluid of the fluid mechanism (Cs) acts on the lower surface (Sc) of the base (B), and the flow direction of the cooling fluid is: A light source device characterized by being in a direction of a difference in height of the stepped surface (Su) in the base (B). 2. The light source device according to claim 1, wherein a flow direction of the cooling fluid is a direction from a higher side to a lower side of the stepped surface (Su) of the base (B). 2. The light source device according to claim 1, wherein the flow direction of the cooling fluid is a direction from a lower side to a higher side of the stepped surface (Su) of the base (B). The fluid mechanism includes at least two systems of the first fluid mechanism (Cs1) and the second fluid mechanism (Cs2), the direction of the cooling fluid flowing through the first fluid mechanism (Cs1), The light source device according to claim 1, wherein the direction of the cooling fluid flowing by the second fluid mechanism (Cs2) is different. As the fluid mechanism, at least two systems of the first fluid mechanism (Cs1) and the second fluid mechanism (Cs2) are provided, and the direction and flow rate of the cooling fluid flowing through the first fluid mechanism (Cs1) The light source device according to claim 1, wherein the direction and flow rate of the cooling fluid flowing by the second fluid mechanism (Cs2) can be independently controlled. The lower surface (Sc) of the base (B) has a protruding structure (Cb) for increasing the surface area on which the cooling fluid acts, and the surface area due to the protruding structure (Cb). 2. The light source device according to claim 1, wherein the amount of increase varies depending on the direction of the height difference of the stepped surface (Su) in the base (B). The light source device (Uo) according to claim 1, a drive circuit (P1, P2,...) That supplies power to each light emitting element of the element light sources (U1, U2,...), And the fluid mechanism (Cs) are driven. A fluid mechanism drive control circuit (Uc) and an optical fiber (Ef) having one end held by the optical fiber holder (Er), and an irradiation light beam emitted from the other end of the optical fiber (Ef) An illumination device that irradiates an object (Wk) with (Fw).

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