JP2006184234A - Light source device and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device and a lighting system capable of adjusting freely a spectrum distribution of output light, while keeping a small size. <P>SOLUTION: This light source device/lighting system includes a light source 16, a dispersion means 13 for dispersing the light from the light source into lights of respective wavelength components, adjusting means 14, 25 for dimming individually the each light of the each wavelength component dispersed by the dispersion means, and for adjusting an intensity ratio of the lights of the respective wavelength components, and combining means 13, 24, 25 for combining the lights of the respective wavelength components with the intensity ratio regulated by the regulation means, to be output, and the dispersion means and the combining means include a common member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light source device and an illumination device, and more particularly to a light source device and an illumination device suitable for inspection of a light receiving element in a manufacturing process of a light receiving element such as a solid-state imaging element.

As a light source device capable of producing light having an arbitrary spectral distribution, the one disclosed in Patent Document 1 is known. In this device, light emitted from a light source is converted into parallel light by a lens, the parallel light is dispersed using a spectroscopic means, a rectangular spectral image is formed by a cylindrical lens, and the wavelength is measured by a spatial filter such as a liquid crystal panel. After the amount of light is controlled every time, wavelength light is mixed using an optical mixing means to create an arbitrary spectral distribution.
JP-A-4-297225

However, in the light source device described above, since an optical system from the light source to the spatial filter and an optical system from the spatial filter to the emission side are respectively arranged, it is inevitable to increase the size of the device. For example, when used for inspection of a light receiving element such as a solid-state imaging element, it is particularly necessary to reduce the size of the light source device because it is necessary to further arrange a light source uniformizing device or the like.
An object of the present invention is to provide a light source device and an illuminating device that can freely adjust the spectral distribution of output light while being small in size.

  The light source device according to claim 1, wherein the light source device, the dispersion means for dispersing the light from the light source into the light of each wavelength component, and the light of each wavelength component dispersed by the dispersion means are individually dimmed. Adjusting means for adjusting the intensity ratio of the light of each wavelength component; and combining means for combining and outputting the light of each wavelength component whose intensity ratio is adjusted by the adjusting means; and The synthesizing means includes a common member.

  According to a second aspect of the present invention, in the light source device according to the first aspect, the dispersing means includes a spectral member that splits the light from the light source, and a first member that guides the light from the light source to the spectral member. An incident optical system; and a second incident optical system that guides light from the spectral member to the adjusting unit. The combining unit includes a combining member that combines the light from the adjusting unit, and the adjusting unit. A first emission optical system that guides the light to the synthesis optical system, and a second emission optical system that emits the light from the synthesis member. The spectroscopic member and the synthesis member include the first emission optical system. The incident optical system and the second incident optical system each include a common member.

  According to a third aspect of the present invention, in the light source device according to the first or second aspect, the dispersion unit disperses light from the light source into light of each wavelength component to form a spectral image, The adjusting means has a plurality of micromirrors arranged on the spectral image forming surface and arranged along the dispersion direction of the light of each wavelength component, and in the reflection direction of the light incident on each of the micromirrors. Accordingly, the light of each wavelength component is individually reduced.

According to a fourth aspect of the present invention, in the light source device according to the third aspect, the plurality of micromirrors are arranged such that the gaps between the micromirrors are inclined with respect to the arrangement direction. .
According to a fifth aspect of the present invention, in the light source device according to the third aspect, each of the micromirrors is smaller in size with respect to the arrangement direction than the image of each wavelength component in the spectral image. .

  According to a sixth aspect of the present invention, in the light source device according to the first or second aspect, the dispersion unit disperses the light from the light source into light of each wavelength component and converts the light into linearly polarized light to obtain a spectrum. An image is formed, and the adjusting means has a plurality of liquid crystal cells arranged on the spectral image forming surface and arranged along the dispersion direction of the light of each wavelength component, and is incident on each of the liquid crystal cells. The light of each wavelength component is individually attenuated according to the amount of rotation of the polarization plane of the linearly polarized light.

A seventh aspect of the present invention is the light source device according to the sixth aspect, wherein the plurality of liquid crystal cells are arranged so that a boundary line between the liquid crystal cells is inclined with respect to an arrangement direction thereof. is there.
According to an eighth aspect of the present invention, in the light source device according to the sixth aspect, each of the liquid crystal cells is smaller in size with respect to the arrangement direction than the image of each wavelength component in the spectral image. .

  The invention according to claim 9 is the light source device according to any one of claims 3 to 8, wherein the dispersion unit generates a parallel light based on the light from the light source; A dispersion unit that gives a wavelength dispersion action to the parallel light, a selection unit that selects a diffracted light of one order different from the 0th-order diffracted light among the diffracted light generated from the dispersion unit, and a selection unit selected by the selection unit And a condensing unit that condenses one order of diffracted light to form the spectrum image.

  A tenth aspect of the present invention is the light source device according to any one of the first to ninth aspects, and an optical system that uniformizes a light amount distribution of output light from the light source device and guides it to a light irradiation surface. It is equipped with.

  According to the present invention, the spectral distribution of output light can be freely adjusted while being small.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
As illustrated in FIG. 1, the light source device 10 according to the first embodiment includes a light source unit 11, a relay optical system 12, a spectroscope 13, a mirror array unit 14, and a controller 15. In general, light from the light source unit 11 enters the mirror array unit 14 via the relay optical system 12 and the spectroscope 13. This optical path is shown by point hatching in FIG. The light reflected by the mirror array unit 14 becomes output light L _OUT via the spectroscope 13 and the relay optical system 12. This optical path is shown by point hatching in FIG.

  The light source unit 11 includes a lamp 16, an elliptical mirror 17, and a concave mirror 18. The lamp 16 is a white light source such as a xenon lamp or a halogen lamp, and emits light to the front elliptical mirror 17 side and the rear concave mirror 18 side. Since the position of the lamp 16 corresponds to the first focal point 7A of the elliptical mirror 17, the light emitted in front of the lamp 16 is reflected by the elliptical mirror 17 and then condensed on the second focal point 7B of the elliptical mirror 17 (FIG. 2).

  Further, since the center point of the concave mirror 18 is at the first focal point 7A of the elliptical mirror 17, the light emitted behind the lamp 16 is reflected by the concave mirror 18 and returned to the elliptical mirror 17, and the second of the elliptical mirror 17 is reflected. Condensed to the focal point 7B. By disposing the concave mirror 18 behind the lamp 16, the light from the lamp 16 can be used efficiently. The light collected at the second focal point 7B of the elliptical mirror 17 is roughly in the range indicated by point hatching in FIG. The lamp 16 corresponds to “light source” in the claims.

  The relay optical system 12 includes a light source side slit 21, a light source side lens 22, a prism 23, a lens 24, an output side lens 25, and an output side slit 26. The position of the light source side slit 21 corresponds to the second focal point 7B of the elliptical mirror 17 of the light source unit 11, and all the light from the lamp 16 is condensed on the light source side slit 21. An image of the lamp 16 is formed in the light source side slit 21.

The light L1 that has passed through the light source side slit 21 becomes parallel light through the light source side lens 22 (see FIG. 2), and after being bent by the prism 23, passes through half of the effective range of the lens 24 (left side in the figure). Then, the light is condensed on the slit 31 of the spectroscope 13. At this time, an image of the light source side slit 21 is formed in the slit 31.
When the lens 24 is viewed from the slit 31 side of the spectroscope 13 along the optical axis 2A of the lens 24, the passing position of the light L1 in the lens 24 is as shown in FIG. FIG. 4A also shows the effective range of the light source side lens 22. Since the passing position of the light L1 is decentered from the optical axis 2A of the lens 24, the light L1 (FIG. 2) that passes through the lens 24 and enters the slit 31 of the spectroscope 13 is relative to the optical axis 2A of the lens 24. The light travels diagonally and intersects the optical axis 2A on the arrangement surface of the slit 31 of the spectroscope 13.

  The spectroscope 13 includes a slit 31, a prism 32, an aspherical mirror 33, and a reflective grating 34. An extension of the optical axis 2A in the spectroscope 13 is referred to as an “optical axis 3A”. The optical axis 3 </ b> A is bent by the prism 32, bent by the aspherical mirror 33, bent by the grating 34, bent again by the aspherical mirror 33, and then reaches the mirror array unit 14. The optical axis 3A has a substantially Σ shape.

  The light L1 collected on the slit 31 of the spectroscope 13 by the lens 24 passes through the slit 31, and is bent by the prism 32, and is one side with respect to the optical axis 3A (upper side along the plane of FIG. 2). To the light path. Then, it becomes parallel light (L 1) via the aspherical mirror 33 and enters the grating 34. The grating 34 is a planar diffraction grating in which a large number of linear grooves are arranged one-dimensionally at equal intervals. The direction of the straight groove is the vertical direction along the paper surface of FIG.

  For this reason, the parallel light (L1) incident on the grating 34 is subjected to wavelength dispersion action there, and becomes diffracted light (L1) traveling at different angles for each wavelength component of the parallel light (L1). The wavelength dispersion of the diffracted light (L1) by the grating 34 is generated in the direction perpendicular to the paper surface of FIG. The diffracted light (L1) is a diffracted light of an order different from that of the 0th order diffracted light (for example, 1st order diffracted light). The aspherical mirror 33 functions as means for generating parallel light (L1) (a “generation unit” in the claims). The grating 34 functions as means for giving a wavelength dispersion action to the parallel light (L1) (“dispersion part” in the claims).

  The diffracted light (L1) from the grating 34 is schematically illustrated, for example, as shown in FIG. FIG. 5A shows the chromatic dispersion direction of the diffracted light (L1) aligned on the paper surface, and the viewing direction is 90 ° different from FIG. In FIG. 2, the wavelength dispersion direction is a direction perpendicular to the paper surface. As can be seen from FIG. 5A, the light of the wavelength components λ1 to λn of the diffracted light (L1) is generated in different directions from the grating 34 and travels toward the aspherical mirror 33. In FIG. 5A, the wavelength components λ1 to λn of the diffracted light (L1) are shown to be discontinuous, but are actually continuous.

  After that, the light of each wavelength component λ1 to λn of the diffracted light (L1) is incident again on the aspherical mirror 33 and reflected (FIG. 2), and becomes the condensed light (L1) and enters the mirror array unit 14. . This condensed light (L1) is schematically illustrated as shown in FIG. 5B, for example. FIG. 5B shows the wavelength dispersion direction of the condensed light (L1) aligned with the paper surface as in FIG. 5A. In the case of the condensed light (L1), the light of each wavelength component λ1 to λn is generated from the aspherical mirror 33 in the same direction and is incident on the mirror array unit 14 at the same angle.

  In addition, the light of each wavelength component λ1 to λn of the condensed light (L1) is collected on the reflecting surface 4A of the mirror array unit 14 (FIG. 5B, FIG. 2). The condensing position is different for each wavelength component λ1 to λn, and is gradually shifted along the wavelength dispersion direction. Therefore, an elongated spectrum image (L1) as shown in FIG. 6 is formed on the reflection surface 4A of the mirror array unit 14. FIG. 6 is a view of the reflection surface 4A and the spectrum image (L1) of the mirror array unit 14 from the aspherical mirror 33 side along the optical axis 3A. The spectrum image (L1) is formed by collecting images of continuous wavelength components λ1 to λn. The wavelength dispersion direction of the spectrum image (L1) coincides with the longitudinal direction.

  The spectroscope 13 transmits light from the light source unit 11 through the relay optical system 12 in the optical path from the lamp 16 to the mirror array unit 14 (hereinafter referred to as “outward path”) of the light source device 10 (FIG. 2) of the first embodiment. L1 is taken in and functions as means for dispersing the light L1 into light of each of the wavelength components λ1 to λn (“dispersing means” in the claims). Further, the spectroscope 13 in the forward path forms the spectrum image (L1) as shown in FIG. 6 by dispersing the light L1 into light of each wavelength component λ1 to λn. The surface on which the spectrum image (L1) is formed substantially coincides with a reflecting surface 4A of the mirror array unit 14 described below.

  As shown in FIG. 7A, the mirror array unit 14 is provided with a plurality of micro mirrors 41a, 41b,. Each of the micromirrors 41a, 41b,... Constitutes a reflection surface 4A of the mirror array unit 14 by each reflection surface. Moreover, it arrange | positions on the formation surface of the spectrum image (L1) shown in FIG. 6, and is arranged one-dimensionally along the dispersion direction (namely, wavelength dispersion direction) of each wavelength component (lambda) 1-lambdan.

Further, the micromirrors 41a, 41b,... Are all flat rectangular mirrors having the same size, and are regularly arranged in a state where they are aligned vertically and horizontally. The size D in the arrangement direction of the micromirrors 41a, 41b,... Is determined so that the wavelength range δ of the condensed light (L1) incident on each micromirror is about 20 nm, for example.
Furthermore, each micromirror (the micromirror 41a is illustrated in FIG. 7B) is also provided with a hinge 42 for inclining it. In FIG. 7B, the hinge 42 is shown enlarged for easy understanding. In the first embodiment, the hinge 42 is provided in parallel to the wavelength dispersion direction. Therefore, the micromirrors 41a, 41b,... Can be individually tilted around the rotation axis parallel to the wavelength dispersion direction (FIG. 7C). The inclination angle is continuously variable within a certain range and can be adjusted according to a control signal from the controller 15 shown in FIG.

In the following description, the state in which the reflecting surfaces of the micromirrors 41a, 41b,... Are perpendicular to the optical axis 3A of the spectroscope 13 is “reference state”, and the state inclined with respect to the optical axis 3A is “inclined state”. That's it. Note that the reflective surface of the micromirror in the reference state is parallel to the substrate of the mirror array unit 14.
When the micromirrors 41a, 41b,... Are in the reference state, the condensed light (L1) incident on the micromirrors 41a, 41b,... Is reflected there and then travels toward the aspherical mirror 33 again. (FIG. 3). This light L2 is guided to the optical path on the side opposite to the condensed light (L1) with respect to the optical axis 3A (lower side along the plane of FIG. 3). Further, the wavelength components λ1 to λn of the light L2 are generated in the same direction when the micromirrors 41a, 41b,... Are in the reference state, and when viewed from the side, the condensed light (L1) shown in FIG. ) Is the opposite light.

Then, the light again becomes parallel light (L 2) through the aspherical mirror 33 and enters the grating 34 again. This parallel light (L2) travels at different angles for each of the wavelength components λ1 to λn. If each of the micromirrors 41a, 41b,... Is in the reference state, the parallel light shown in FIG. The light is opposite to (L1).
The parallel light (L2) incident on the grating 34 is subjected to chromatic dispersion action there. The wavelength dispersion action at this time is an action opposite to the wavelength dispersion action (that is, the multiplexing action) received when the parallel light (L1) is incident on the grating 34 from the aspherical mirror 33. For this reason, the parallel light (L2) is diffracted light (L2) in which all the wavelength components λ1 to λn travel at the same angle by the multiplexing action of the grating 34 if each of the micromirrors 41a, 41b,. ).

After that, the diffracted light (L2) becomes condensed light (L2) through the aspherical mirror 33, is bent by the prism 32, and then condensed on the slit 31 (FIG. 3). The light L2 collected on the slit 31 by the aspherical mirror 33 passes through the slit 31, and then returns from the spectroscope 13 to the relay optical system 12.
In the relay optical system 12, the light L <b> 2 enters and passes through the remaining half (right side of the drawing) of the effective range of the lens 24. The light L <b> 2 that has passed through the lens 24 is parallel light, is bent by the prism 23, and then condensed on the output side slit 26 via the output side lens 25. Then, it passes through the output slit 26 and becomes output light L _OUT .

In the optical path from the mirror array unit 14 to the output-side slit 26 of the relay optical system 12 (hereinafter referred to as “return path”), the spectroscope 13 and the lenses 24 and 25 each have a wavelength of the light L2 from the mirror array unit 14. It functions as means for combining and outputting the light of the components λ1 to λn (“combining means” in the claims).
Here, the passing position of the light L2 in the lens 24 is as shown in FIG. FIG. 4B also shows the effective range of the output side lens 25. If the micromirrors 41a, 41b,... Of the mirror array unit 14 are in the reference state, the effective range of the output side lens 25 and the passing positions of the wavelength components λ1 to λn of the light L2 coincide with each other and overlap each other. .

Therefore, if each of the micromirrors 41a, 41b,... Is in the reference state, each wavelength component λ1 to λn of the light L2 can pass through the output side lens 25 without being vignetted by the effective range of the output side lens 25. The output light L _OUT passes through the output side slit 26. The spectral distribution of the output light L _OUT at this time is determined by the spectral distribution of the light emitted from the lamp 16 and the spectral characteristics of the optical system such as the grating 34. FIG. 8 shows an example of the spectral distribution of the output light L _OUT . In FIG. 8, the horizontal axis represents wavelength and the vertical axis represents intensity.

In the light source device 10 of the first embodiment, in order to change the spectral distribution of the output light L _OUT , each micro mirror 41a, 41b,... Of the mirror array unit 14 (FIG. 7) may be individually inclined.
For example, when one micromirror 41d is tilted (FIG. 9 (a)), the light L2 reflected by the micromirror 41d (the wavelength components included therein are denoted by λ _41d to λ _41d + δ) Depending on the tilt angle of the mirror 41d, it is generated in a direction different from the light L2 in the reference state. Therefore, when the light L2 enters the lens 24 of the relay optical system 12 via the spectroscope 13 (FIG. 3), the position of the light L2 is indicated by an arrow from the effective range of the output side lens 25 as shown in FIG. Will shift in the direction.

Then, the portion L2 (1) out of the effective range of the output side lens 25 in the light L2 in FIG. 4C is vignetted when passing through the output side lens 25 and overlaps the effective range of the output side lens 25. Only the portion L2 (2) that is present passes through the output side lens 25 without vignetting. Then, a part of the light L2 (2) that has passed through the output side lens 25 passes through the output side slit 26 and then becomes the output light L _OUT .

The spectral distribution of the output light L _OUT at this time is different from the spectral distribution of FIG. 8, for example, as shown in FIG. 9B. In the spectral distribution of FIG. 9B, the intensity is attenuated and dimmed in the wavelength range of the light L2 reflected by the tilted micromirror 41d (each wavelength component λ _{41d to} λ _41d + δ). .
Further, when the inclination angle of the micro mirror 41d is changed, the reflection direction of the light L2 reflected by the micro mirror 41d is changed, and the amount of vignetting when passing through the output side lens 25 is changed, so that the spectrum of the output light L _OUT is changed. In the distribution (FIG. 9B), the amount of light reduction in the wavelength range (each wavelength component λ _{41d to} λ _41d + δ) of the micromirror _41d can be changed. This amount of light reduction is proportional to the tilt angle of the micromirror 41d (not directly proportional).

The same applies to the other micromirrors 41a, 41b,..., And when the micromirrors 41a, 41b,... Are individually inclined, the wavelength ranges corresponding to the micromirrors 41a, 41b,. _{41a ~λ 41a + δ, λ 41b} ~λ 41b + δ, in ...) it can be individually dimmed to. Furthermore, the amount of light reduction can be changed in proportion to each inclination angle.

In the light source device 10 of the first embodiment, the mirror array unit 14 and the output side lens 25 are in the reflection direction (see FIG. 9A) of the light (L1) incident on each of the micromirrors 41a, 41b,. Accordingly, each wavelength component λ1 to λn of the light (L2) is individually dimmed and functions as means for adjusting the intensity ratio (“adjustment means” in the claims). Then, the light L2 of the wavelength components λ1 to λn whose intensity ratio is adjusted is output in a combined state (output light L _OUT ).

Therefore, according to the light source device 10 of the first embodiment, the spectral distribution of the output light L _OUT can be freely adjusted by individually setting the micromirrors 41a, 41b,. Can do. As a result, output light L _OUT having an arbitrary spectral distribution can be obtained. Further, the light amount of the output light L _OUT can be easily adjusted by adjusting the mirror array unit 14.

For example, when the micromirrors 41a, 41b,... Are all in the reference state, white light having a spectral distribution as shown in FIG. 8 can be obtained as the output light _LOUT . Further, the color temperature of the output light L _OUT can be adjusted as in the case of using the conventional dielectric multilayer filter. Further, similarly to the case of using a conventional monochromator, monochromatic light having a narrow wavelength range can be obtained as the output light L _OUT, and the wavelength range of the monochromatic light can be adjusted. Further, the light source device 10 of the first embodiment can be used as a light source device for measuring the efficiency of the solar cell, and the sunlight spectrum can be simulated.

The wavelength resolution of the light source device 10 of the first embodiment depends on the size D (FIG. 7A) in the arrangement direction of the micromirrors 41a, 41b,. When the wavelength range δ of the light (L1) incident on each micromirror is, for example, about 20 nm, the wavelength resolution is also about 20 nm. In this case, the spectral distribution of the output light L _OUT can be adjusted in detail with a wavelength resolution of about 20 nm.

In actual adjustment, the correspondence between the tilt angles of the micromirrors 41a, 41b,... And the light reduction amounts of the respective wavelength components λ1 to λn is stored in advance as a table (or calculation formula) in the memory of the controller 15 (FIG. 1). The Further, the spectrum distribution (for example, FIG. 8) when all the micromirrors 41a, 41b,... Are set in the reference state is also stored in the memory in advance. Then, the controller 15 adjusts the spectral distribution of the output light L _OUT according to the following procedures [1] to [3].

[1] In accordance with an instruction from the outside, the light reduction amount of each wavelength component λ1 to λn necessary for realizing a desired spectral distribution is changed to a wavelength range corresponding to each of the micromirrors 41a, 41b,. _{λ 41a ~λ 41a + δ, λ} 41b ~λ 41b + δ, ...) is calculated for each. [2] Based on each calculated light reduction amount, the “correspondence relationship between the inclination angle and the light reduction amount” is referred to, and the inclination angles of the micromirrors 41a, 41b,. [3] The micromirrors 41a, 41b,... Are controlled based on the obtained inclination angle.

As described above, in the light source device 10 of the first embodiment, the controller 15 controls the light reduction amount of each wavelength component λ1 to λn according to an instruction from the outside, and the intensity ratio of each wavelength component λ1 to λn as instructed. Is set ("setting means" in claims). As a result, a desired spectral distribution can be realized as the spectral distribution of the output light L _OUT from the light source device 10. Here, the open loop control has been described as an example.

Furthermore, in the light source device 10 of the first embodiment, there are a number of outgoing paths from the lamp 16 of the light source unit 11 to the mirror array unit 14 and a return path from the mirror array unit 14 to the output slit 26 of the relay optical system 12. Since the optical elements (23, 24, 31 to 34) are shared, the apparatus can be downsized.
Further, in the light source device 10 of the first embodiment, the order cut filter 19 as shown in FIG. 10 is arranged in front of the reflecting surface 4A of the mirror array unit 14, so that it is possible to cope with a broad spectrum distribution. When the spectrum distribution is broadened, there is a possibility that high-order light having a short wave component is superimposed on the long wave side. If unnecessary high-order light is superimposed, it becomes difficult to accurately adjust the spectral distribution.

The order cut filter 19 shown in FIG. 10 is means for selecting one order diffracted light (for example, the first order diffracted light) different from the zeroth order diffracted light from the diffracted light generated from the grating 34 (“selection unit” in the claims). Function as. Specifically, the filter is composed of a long-wave filter 9A and a short-wave filter 9B, and the high-order light of unnecessary short-wave components (components having a wavelength λ _CUT or less) is blocked by the long-wave filter 9A, thereby _reducing one order. Only the diffracted light is selected. The short wave filter 9B is a dummy glass provided to adjust the optical path length.

  As described above, by arranging the order cut filter 19 in front of the reflecting surface 4A of the mirror array unit 14, even when the spectrum distribution is broadened, only one order of diffracted light is always guided to the mirror array unit 14. Thus, a spectral image (L1) can be formed. Therefore, even when the spectral distribution is broadened, the spectral distribution can be adjusted accurately. Furthermore, since the spectral distribution is broadened, the degree of freedom in adjusting the spectral distribution is increased.

Furthermore, when the homogenization optical system 60 of FIG. 11 is arranged at the subsequent stage of the light source device 10 of the first embodiment, and the illumination device (10, 60) is configured by the light source device 10 and the homogenization optical system 60, the light The irradiation surface 60A can be uniformly illuminated with light having various spectral distributions. The uniformizing optical system 60 in FIG. 11 is an optical system that uniformizes the light amount distribution of the output light L _OUT from the light source device 10 and guides it to the light irradiation surface 60A.

More specifically, the output light L _OUT from the light source device 10 becomes parallel light through the lens 61 and enters the fly-eye lens 62. On the exit side of the fly-eye lens 62, the same number of condensing points as the lens elements appear. Condensed light from each lens element of the fly-eye lens 62 becomes parallel light via the lens 63 and overlaps on the arrangement surface of the field stop 64 to illuminate the field stop 64 uniformly.

  The light that has passed through the field stop 64 enters the light irradiation surface 60 </ b> A via the lens 65, the mirror 66, the aperture stop 67, and the projection lens 68. An image of the field stop 64 is projected onto the light irradiation surface 60A. The image of the field stop 64 projected on the light irradiation surface 60A becomes an actual illumination area. The size of the illumination area is obtained by multiplying the size of the field stop 64 by a magnification according to the ratio of the focal lengths of the lens 65 and the projection lens 68.

In the illuminating device (10, 60), the mirror array unit 14 of the light source device 10 is controlled by the controller 15 so that the spectral distribution of the output light L _OUT from the light source device 10 can be freely adjusted. 60A can be telecentric illuminated by uniform light with various spectral distributions. In place of the fly-eye lens 62 of the homogenizing optical system 60, a rod lens, a diffusion plate, or the like may be used.

  The illumination device (10, 60) can be used for inspection of a solid-state imaging device typified by a CCD or a CMOS sensor and various types of light-receiving elements. In this inspection, a test object such as a solid-state image sensor is arranged on the light irradiation surface 60A of the illumination device (10, 60), and the test is sequentially performed by uniform light of various spectral distributions from the illumination device (10, 60). Illuminate the object. Then, a tester checks whether the response under each lighting condition is as designed. At this time, the spectral sensitivity can be measured by irradiating monochromatic light having a narrow wavelength range.

In the light source device 10 of the first embodiment, the hinges 42 of the micromirrors 41a, 41b,... Of the mirror array unit 14 (FIG. 7) are provided in parallel to the wavelength dispersion direction, but the present invention is not limited to this. . For example, as shown in FIG. 12, each hinge 42 may be provided perpendicular to the wavelength dispersion direction. In this case, the passage position of the light L2 in the lens 24 of the relay optical system 12 is shifted from the effective range of the output side lens 25 in the direction of the arrow as shown in FIG.
(Second Embodiment)
In the light source device of the second embodiment, a mirror array unit 45 shown in FIG. 13 is provided instead of the mirror array unit 14 (FIGS. 7 and 12) of the light source device 10 of the first embodiment.

7 and 12, the gap between the micromirrors is perpendicular to the arrangement direction (wavelength dispersion direction) of the micromirrors 41a, 41b,. Since the wavelength light corresponding to the gap portion is not output, when the spectral distribution of the output light L _OUT is examined in detail, there are subtle ripples as shown in FIG. In order to suppress this, it is conceivable to reduce the gap, but there is actually a limit.

  Therefore, in the light source device of the second embodiment, the gap between the micromirrors is inclined with respect to the arrangement direction (wavelength dispersion direction) of the micromirrors 45a, 45b,... As in the mirror array unit 45 of FIG. In this manner, the micromirrors 45a, 45b,. By making the gap oblique, it is possible to disperse the wavelength light that cannot enter the gap and contribute to the output light in a wide wavelength range, and the ripple can be reduced (FIG. 13B).

In the mirror array unit 45, the hinges 46 of the respective micromirrors 45a, 45b,... May be provided in the direction as shown in FIG. 13 (c) or as shown in FIG. The passing position of the light L2 in the lens 24 of the relay optical system 12 is shifted obliquely in the direction of the arrow from the effective range of the output side lens 25 as shown in FIG.
Further, as shown in FIG. 15, the direction of the gap between the micromirrors of the mirror array unit 45 is such that one end 47A and the other end 47B of the gap between the micromirrors overlap with the spectrum image (L1) It is preferable to set the relationship. That is, for example, the other end 47B and the one end 47A of the adjacent gaps between the other end 47B of the gap between the micromirrors 45a and 45b and the one end 47A of the gap between the micromirrors 45b and 45c are in the wavelength dispersion direction. And a vertical positional relationship is preferable. In this case, gaps (that is, portions having low reflectivity) can be equally dispersed in all wavelength components λ1 to λn of the spectrum image (L1), and ripples can be reliably reduced.

In addition, in order to reduce the ripple (FIG. 14) in the spectrum distribution of the output light L _OUT , in addition to the above-described method of making the gap between the micromirrors oblique, the size related to the arrangement direction (wavelength dispersion direction) of each micromirror. A method is conceivable in which the height D is made smaller than the size E of the image of each wavelength component λ1 to λn (monochromatic image L1 (λ _J )) in the spectral image (L1) shown in FIG. FIG. 16 illustrates an example in which the size D of each micromirror is the same as that in FIG. 7 and the size E of the monochromatic image L1 (λ _J ) is widened. The wavelength resolution in this case depends not on the size D of each micromirror but on the size E of the monochromatic image L1 (λ _J ). The size E of the monochromatic image L1 (λ _J ) is determined by the imaging performance of the slit 31 of the spectroscope 13 (FIG. 2) and the optical system that forms the image (concave mirror 33 in this embodiment).
(Third embodiment)
As shown in FIG. 17, the light source device 70 of the third embodiment is provided with a polarizing element 71 between the prism 23 and the lens 24 of the relay optical system 12, and reflective liquid crystal instead of the MEMS mirror array unit 14. An element 72 is provided.

The liquid crystal element 72 is, for example, LCOS (Liquid Crystal on Silicon), and includes a plurality of liquid crystal cells 73a, 73b,... As shown in FIG. The liquid crystal cells 73a, 73b,... Are arranged on the surface on which the spectral image (L1) is formed, and are arranged one-dimensionally along the light dispersion direction (that is, the wavelength dispersion direction) of each wavelength component λ1 to λn. Yes.
In the light source device 70 of the third embodiment, light (L 1) that has been converted into linearly polarized light by passing through the polarizing element 71 enters the liquid crystal element 72 in the forward path from the lamp 16 to the liquid crystal element 72. A spectrum image (L1) similar to the above is formed on the incident surface of the liquid crystal element 72.

  In the liquid crystal element 72, for each liquid crystal cell 73a, 73b,..., The polarization plane of the incident linearly polarized light is rotated by an amount proportional to the applied voltage, and the linearly polarized light whose polarization plane is rotated is reflected. For this reason, the light (L2) emitted from the liquid crystal element 72 and returned to the polarizing element 71 is attenuated by an amount proportional to the amount of rotation of the polarization plane when passing through the polarizing element 71. For example, when the amount of rotation of the polarization plane is 90 °, almost all of the light is extinguished, but actually, it depends on the extinction ratio of the polarizing element 71.

As described above, in the light source device 70 of the third embodiment, by individually adjusting the amount of rotation of the polarization plane in each liquid crystal cell 73a, 73b,... Of the liquid crystal element 72, each wavelength component according to each amount of rotation. The light of λ1 to λn can be individually attenuated, and the spectral distribution of the output light L _OUT can be freely adjusted. As a result, output light L _OUT having an arbitrary spectral distribution can be obtained. Further, the light amount of the output light L _OUT can be easily adjusted by adjusting the mirror array unit 14.

In the light source device 70 of the third embodiment, it is preferable that the polarization direction of the polarizing element 71 is aligned with the direction in which the diffraction efficiency of the grating 34 is the highest in order to secure the light amount of the output light L _OUT .
Even when the liquid crystal element 72 is used, a delicate ripple is generated at the boundary line between the liquid crystal cells (see FIG. 14). Therefore, it is preferable to arrange each liquid crystal cell 73a, 73b,... So that the boundary line between the liquid crystal cells is inclined with respect to the arrangement direction (wavelength dispersion direction) of each liquid crystal cell 73a, 73b,. (See FIGS. 13 and 15). By making the boundary line between the liquid crystal cells oblique, the low reflectance portion can be dispersed in a wide wavelength range, and ripple can be reduced (see FIG. 13B).

Further, the size D related to the arrangement direction (wavelength dispersion direction) of each liquid crystal cell is set to the size of the image of each wavelength component λ1 to λn (monochromatic image L1 (λ _J )) in the spectral image (L1) shown in FIG. Ripple may be reduced by making it smaller than E.
Further, in the third embodiment, the order cut filter 19 shown in FIG. 10 can be arranged in front of the liquid crystal element 72 to cope with the broadening of the spectrum distribution of the output light L _OUT . Further, by combining with the uniformizing optical system 60 of FIG. 11, the light irradiation surface 60A can be telecentric illuminated with uniform light having various spectral distributions.
(Modification)
In the above-described embodiment, each micromirror (or liquid crystal cell) is open-loop controlled by the controller 15, but the present invention is not limited to this. The present invention can also be applied to the case where each micromirror (or liquid crystal cell) is closed-loop controlled by the controller 15. In this case, a mirror 81 that reflects only a part of the light and a small spectrophotometer 82 are arranged at the subsequent stage of the light source device (for example, between the lens 63 and the field stop 64 of the uniformizing optical system 80 shown in FIG. 20). The spectral distribution of the output light L _OUT is monitored, and the result is fed back to the controller 15.

Furthermore, in the above-described embodiment, an example has been described in which each micromirror (or liquid crystal cell) can be controlled in accordance with an instruction from the outside, but the present invention is not limited to this. The present invention can also be applied when the controller 15 is not provided in the light source device.
In the above-described embodiment, the forward path from the lamp 16 of the light source unit 11 to each micromirror (or liquid crystal cell) and the return path from each micromirror (or liquid crystal cell) to the output slit 26 of the relay optical system 12 In the above, an example in which a large number of optical elements (23, 24, 31 to 34) are shared has been described, but the forward path and the return path may be configured using different optical elements. An optical fiber may be used for introducing light from the light source unit 11 to the relay optical system 12 and for introducing light from the relay optical system 12 to the uniform optical systems 60 and 80.

  Furthermore, in configuring the light source device, the reflection type grating 34 is used, but a transmission type grating may be used. Instead of the reflective optical element such as the aspherical mirror 33, a transmissive optical element (lens) may be used.

It is a figure which shows the whole structure of the light source device 10 of 1st Embodiment. The forward path from the lamp 16 to the mirror array unit 14 will be described. It is a figure explaining the return path from the mirror array part 16 to the output side slit 26. FIG. It is a figure explaining the passage position of light L1, L2 in the lens 24. FIG. It is a figure which shows typically the diffracted light (L1) from the grating 34, and the condensing light (L1) to the mirror array part 14. FIG. It is a figure explaining the spectrum image (L1) of a shape. It is a figure explaining the mirror array part. It is a figure explaining the spectrum distribution of the output light _LOUT when all the micromirrors 41a, 41b, ... are in a reference state. It is a diagram illustrating the reflected light L2 of the spectral distribution of the output light L _OUT when tilting the micromirror 41d. It is a figure explaining the order cut filter. FIG. 2 is a diagram showing a configuration when a uniformizing optical system 60 is arranged at the subsequent stage of the light source device 10. It is a figure explaining the other example of arrangement | positioning of the hinge 42 of each micromirror 41a, 41b, .... It is a figure which shows the structure of the mirror array part 45 of the light source device of 2nd Embodiment. It is a figure which expands and shows the ripple which appears in the spectrum distribution of output light _LOUT . FIG. 3 is a diagram illustrating a preferred configuration of a mirror array unit 45. It is a figure explaining the magnitude | size D of each micromirror, and the magnitude | size E of the monochrome image L1 ((lambda) _J ). It is a figure which shows the whole structure of the light source device 70 of 3rd Embodiment. It is a figure explaining liquid crystal cell 72a, 72b, ... of the liquid crystal element 72 of the light source device 70. FIG. It is a figure explaining the structural example which provides the spectrophotometer 82 in the back | latter stage of a light source device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,70 Light source device 11 Light source part 12 Relay optical system 13 Spectroscope 14,45 Mirror array part 15 Controller 16 Lamp 17 Elliptical mirror 18 Concave mirror 19 Order cut filter 21, 26, 31 Slit 22, 24, 25 Lens 23, 32 Prism 33 Aspherical mirror 34 Grating 41a, 45a Micro mirror 42, 46 Hinge 60, 80 Homogenizing optical system 62 Fly eye lens 64 Field stop 60A Light irradiation surface 71 Polarizing element 72 Liquid crystal element 82 Spectrophotometer

Claims (10)

A light source;
Dispersion means for dispersing light from the light source into light of each wavelength component;
Adjusting means for individually dimming the light of each wavelength component dispersed by the dispersing means, and adjusting the intensity ratio of the light of each wavelength component;
Combining means for combining and outputting the light of each wavelength component, the intensity ratio of which has been adjusted by the adjusting means,
The dispersion unit and the synthesis unit include a common member. The light source device according to claim 1,
The dispersing means includes a spectral member that splits the light from the light source, a first incident optical system that guides the light from the light source to the spectral member, and a second that guides the light from the spectral member to the adjusting means. The incident optical system,
The combining unit includes a combining member that combines the light from the adjusting unit, a first emission optical system that guides the light from the adjusting unit to the combining optical system, and a second unit that emits the light from the combining member. It consists of the injection optical system of
The light source device, wherein the spectroscopic member and the combining member, and the first incident optical system and the second incident optical system each include a common member. The light source device according to claim 1 or 2,
The dispersion means forms a spectral image by dispersing light from the light source into light of each wavelength component,
The adjusting means has a plurality of micromirrors arranged on the spectral image forming surface and arranged along the dispersion direction of the light of each wavelength component, and the reflection direction of the light incident on each of the micromirrors The light source device characterized in that the light of each wavelength component is individually dimmed according to the above. The light source device according to claim 3.
The plurality of micromirrors are arranged such that gaps between the micromirrors are inclined with respect to the arrangement direction. The light source device according to claim 3.
Each of the micromirrors has a size in the arrangement direction smaller than the size of each wavelength component in the spectrum image. The light source device according to claim 1 or 2,
The dispersing means disperses the light from the light source into light of each wavelength component and converts it into linearly polarized light to form a spectral image,
The adjusting means has a plurality of liquid crystal cells arranged on the spectral image forming surface and arranged along the dispersion direction of the light of each wavelength component, and the linearly polarized light incident on each of the liquid crystal cells. A light source device characterized by individually dimming light of each wavelength component according to the amount of rotation of the polarization plane. The light source device according to claim 6,
The plurality of liquid crystal cells are arranged so that a boundary line between the liquid crystal cells is inclined with respect to an arrangement direction thereof. The light source device according to claim 6,
Each of the liquid crystal cells has a size in the arrangement direction smaller than the size of each wavelength component image in the spectrum image. The light source device according to any one of claims 3 to 8,
The dispersion means includes a generation unit that generates parallel light based on light from the light source, a dispersion unit that imparts wavelength dispersion to the parallel light, and zero-order diffracted light among diffracted light generated from the dispersion unit. And a selection unit that selects one order of diffracted light, and a condensing unit that collects the one order of diffracted light selected by the selection unit and forms the spectrum image. Light source device. The light source device according to any one of claims 1 to 9,
An illuminating device comprising: an optical system that uniformizes a light amount distribution of output light from the light source device and guides it to a light irradiation surface.

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