JP2014126836A - Illumination device, projection device, scanner, and exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination device capable of minimizing loss of diffracted light and accurately identifying presence of change in characteristics of a diffraction optical element using a simple configuration.SOLUTION: An illumination device 10 includes; a light source 11; a diffraction optical element 12 having a first element 121 and a second element 122, of which the first element diffracts light emitted from the light source to illuminate an illuminating target area with diffracted light L11 and the second element diffracts the light emitted from the light source in a different direction from a diffraction direction of the first element; a first photodetector 13 which detects at least a portion of regular reflection light L12 reflected from an incident surface of the diffraction optical element; a second photodetector 14 which detects at least a portion of diffracted light L13 generated by the second element of the diffraction optical element; and a determination unit 15 which computes a relative value from a first detection value detected by the first photodetector and a second detection value detected by the second photodetector and determines whether characteristic of the diffraction optical element has changed or not based on changes in the relative value and the first detection value.

Description

  The present invention relates to an illumination device, a projection device, a scanner, and an exposure device that include a diffractive optical element that diffracts incident light and that can determine whether or not the characteristics of the diffractive optical element have changed.

  A technique for configuring a projection device, a scanner, an exposure device, and the like using an illumination device including a diffractive optical element has been proposed. In such an apparatus, it is preferable that the presence or absence of deterioration of the diffractive optical element due to secular change or the like can be detected from the viewpoints of safety and maintainability.

  For example, in Patent Document 1, a part of the light diffracted by the diffractive optical element is branched using a beam splitter or the like, and the presence or absence of deterioration of the diffractive optical element is detected based on the detection result of the branched light. Technology is disclosed.

  In Patent Document 2, detection light is incident on an optical element such as a lens from a direction different from incident light, reflected light of the detection light is detected by a detector, and whether or not the optical element is damaged is detected based on the detection result. Technology is disclosed. It is also conceivable to apply this technique to a diffractive optical element.

JP 2012-32379 A JP 2009-134217 A

  However, in the technique described in Patent Document 1, since a part of necessary diffracted light used for illumination is branched, the use efficiency of light is reduced when it is incorporated in an illumination device or the like. Further, since optics such as a beam splitter for branching is required, the optical system becomes complicated.

  Further, the technique described in Patent Document 2 requires a light source having a different wavelength for detection light or an element for converting to a different wavelength, so that the optical system becomes complicated.

  Furthermore, in both of the above techniques, when the detection value of the detector changes, it is caused by deterioration of the diffractive optical element or is already incident on the diffractive optical element due to the state of the optical path before the diffractive optical element. It is impossible to grasp whether the cause is that the amount of light to be reduced is the cause. When the amount of light incident on the diffractive optical element is reduced, it may be caused by, for example, a decrease in the output of the light source or deterioration of optics before the diffractive optical element. That is, it cannot be accurately determined whether or not the characteristics of the diffractive optical element have changed.

  Accordingly, an object of the present invention is to provide an illuminating device that can accurately determine whether or not the characteristics of a diffractive optical element have changed with a simple configuration, with a minimum loss of diffracted light.

The lighting device according to the present invention comprises:
A light source;
A diffractive optical element including a first element and a second element, wherein the first element diffracts light emitted from the light source, illuminates an illumination area with the diffracted light, and the second element A diffractive optical element that diffracts light emitted from the light source in a direction different from the diffraction direction of the first element;
A first photodetector for detecting at least part of the specularly reflected light reflected by the incident surface of the diffractive optical element;
A second photodetector for detecting at least part of the diffracted light generated by the second element of the diffractive optical element;
A relative value between the first detection value of the first photodetector and the second detection value of the second photodetector is calculated, and based on a change in the relative value and the first detection value. A determination unit for determining whether or not the characteristics of the diffractive optical element have changed,
Is provided.

In the lighting device according to the present invention,
The determination unit may determine that the characteristics of the diffractive optical element have changed in the first case where the first detection value does not change and the relative value changes.

In the lighting device according to the present invention,
In the second case where the first detection value decreases and the relative value does not change, the determination unit does not change the characteristics of the diffractive optical element and is incident on the diffractive optical element. It may be determined that the amount of light has decreased.

In the lighting device according to the present invention,
The first element and the second element may have the same incident angle of light from the light source and the same diffraction wavelength.

In the lighting device according to the present invention,
The area of the incident surface of the second element may be set to a minimum value at which at least a part of the diffracted light generated by the second element can be detected by the second photodetector.

In the lighting device according to the present invention,
The incident surface of the first element and the incident surface of the second element may constitute the same plane.

In the lighting device according to the present invention,
The second element may be stacked on the first element.

In the lighting device according to the present invention,
An antireflection layer may be provided on at least one of the incident surface and the back surface of the diffractive optical element.

In the lighting device according to the present invention,
Between the first photodetector and the diffractive optical element, and between the second photodetector and the diffractive optical element, the light reaching the first and second photodetectors You may provide the light quantity adjustment filter which reduces a light quantity.

In the lighting device according to the present invention,
In the first case and the second case, the light source may include a control unit that stops emission of light.

In the lighting device according to the present invention,
You may provide the display part which displays 1st error information in the said 1st case, and displays 2nd error information in the said 2nd case.

The projection apparatus according to the present invention
A lighting device;
A spatial light modulator illuminated by the illumination device;
A projection optical system that projects a modulated image obtained on the spatial light modulator onto a screen;
With
The lighting device includes:
A light source;
A diffractive optical element including a first element and a second element, wherein the first element diffracts light emitted from the light source, illuminates the spatial light modulator with diffracted light, and The second element diffracts the light emitted from the light source in a direction different from the diffraction direction in the first element;
A first photodetector for detecting at least part of the specularly reflected light reflected by the incident surface of the diffractive optical element;
A second photodetector for detecting at least part of the diffracted light generated by the second element of the diffractive optical element;
A relative value between the first detection value of the first photodetector and the second detection value of the second photodetector is calculated, and based on a change in the relative value and the first detection value. A determination unit for determining whether or not the characteristics of the diffractive optical element have changed,
Have

The scanner according to the present invention
An illumination device for illuminating a scan object;
An information acquisition unit that acquires surface information of the illuminated scan object;
With
The lighting device includes:
A light source;
A diffractive optical element including a first element and a second element, wherein the first element diffracts light emitted from the light source, illuminates the scan object with diffracted light, and The diffractive optical element diffracts the light emitted from the light source in a direction different from the diffraction direction in the first element;
A first photodetector for detecting at least part of the specularly reflected light reflected by the incident surface of the diffractive optical element;
A second photodetector for detecting at least part of the diffracted light generated by the second element of the diffractive optical element;
A relative value between the first detection value of the first photodetector and the second detection value of the second photodetector is calculated, and based on a change in the relative value and the first detection value. A determination unit for determining whether or not the characteristics of the diffractive optical element have changed,
Have

An exposure apparatus according to the present invention comprises:
A lighting device;
A spatial light modulator illuminated by the illumination device,
The light modulated by the spatial light modulator is guided to the surface of the photosensitive medium,
The lighting device includes:
A light source;
A diffractive optical element including a first element and a second element, wherein the first element diffracts light emitted from the light source, illuminates the spatial light modulator with diffracted light, and The second element diffracts the light emitted from the light source in a direction different from the diffraction direction in the first element;
A first photodetector for detecting at least part of the specularly reflected light reflected by the incident surface of the diffractive optical element;
A second photodetector for detecting at least part of the diffracted light generated by the second element of the diffractive optical element;
A relative value between the first detection value of the first photodetector and the second detection value of the second photodetector is calculated, and based on a change in the relative value and the first detection value. A determination unit for determining whether or not the characteristics of the diffractive optical element have changed,
Have

  According to the present invention, it is possible to accurately determine whether or not the characteristics of the diffractive optical element have changed with a simple configuration, with a minimum loss of diffracted light.

It is a figure which shows schematic structure of the illuminating device which concerns on 1st Embodiment. (A) is a top view of the diffractive optical element of FIG. 1, (b) is AA sectional drawing of a diffractive optical element, (c) is AA of the diffractive optical element which concerns on a modification. It is sectional drawing. It is a figure which shows schematic structure of the illuminating device which concerns on 2nd Embodiment. It is a figure which shows schematic structure of the illuminating device which concerns on 3rd Embodiment. It is a figure which shows schematic structure of the projection type video display apparatus concerning 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

(First embodiment)
FIG. 1 is a diagram illustrating a schematic configuration of a lighting device 10 according to the first embodiment. 2A is a plan view showing the diffractive optical element 12 of FIG. 1, FIG. 2B is a cross-sectional view of the diffractive optical element 12, and FIG. 2C is a modified example. It is AA sectional drawing of the diffractive optical element 12 which concerns on.

  As illustrated in FIG. 1, the illumination device 10 includes a light source 11 that emits light L10, a diffractive optical element 12, a first photodetector 13, a second photodetector 14, a determination unit 15, Is provided. The first photodetector 13, the second photodetector 14, and the determination unit 15 can also be referred to as a diffractive optical element characteristic tracking device or a diffractive optical element characteristic evaluation device.

  As shown in FIG. 2, the diffractive optical element 12 includes a first element 121 and a second element 122. The rectangular first element 121 is provided on the substrate 123. The second element 122 is provided in the vicinity of two vertices of the first element 121 so as to be embedded in the first element 121. The incident surface 12 a of the first element 121 and the incident surface 12 a of the second element 122 constitute the same plane as the incident surface 12 a of the diffractive optical element 12.

  The area of the incident surface 12 a of the first element 121 is larger than the area of the incident surface 12 a of the second element 122. The area of the incident surface 12a of the second element 122 is preferably narrow as long as diffracted light can be detected as will be described later.

  As shown in FIG. 1, the first element 121 diffracts the light L10 emitted from the light source 11 and illuminates the illumination area with a diffracted light L11 of a predetermined order. In the present embodiment, the diffracted light L11 having a predetermined order is a first-order diffracted light.

  The second element 122 diffracts the light L10 emitted from the light source 11 in a direction different from the diffraction direction in the first element 121.

  The first element 121 and the second element 122 have the same incident angle of the light L10 emitted from the light source 11 and the same diffraction wavelength.

The first element 121 and the second element 122 are reflective diffractive optical elements, and the first-order diffracted light L11 is emitted from the incident surface 12a of the diffractive optical element 12.
The first element 121 and the second element 122 may be, for example, a volume hologram recording medium, or a relief or embossed hologram recording medium.

  When the first element 121 and the second element 122 are volume hologram recording media, as an example of a method for manufacturing the diffractive optical element 12, first, a hologram is formed in a region on the substrate 123 where the first element 121 is formed. A photosensitive material is formed.

  Next, the hologram photosensitive material is exposed in a state where a region for forming the second element 122 is masked to form the first element 121.

  Next, the hologram photosensitive material is exposed in a state where the first element 121 is masked to form the second element 122.

  2C, the second element 122 may be stacked on the first element 121. As shown in FIG. In this case, a layer 124 such as glass or a film is laminated on the first element 121 on which the second element 122 is not laminated so that irregularities are not formed on the incident surface 12a.

  Returning to FIG. 1, part of the light L <b> 10 incident on the diffractive optical element 12 is specularly reflected, that is, specularly reflected by the incident surface 12 a of the diffractive optical element 12.

  The first photodetector 13 detects at least a part of the regular reflection light L12 specularly reflected by the incident surface 12a of the diffractive optical element 12, and outputs a first detection value corresponding to the detected light amount. In the present embodiment, it is assumed that the first photodetector 13 detects the specularly reflected light L12 that is specularly reflected by the incident surface 12a of the first element 121 of the diffractive optical element 12.

  The light source 11 and the diffractive optical element 12 are arranged so that the regular reflection light L12 is reflected at a position different from the position of the light source 11. That is, the light source 11 and the diffractive optical element 12 are arranged so that the light L10 does not enter perpendicularly to the incident surface 12a.

The second photodetector 14 detects at least a part of the diffracted light L13 generated by the second element 122 of the diffractive optical element 12, and outputs a second detection value corresponding to the detected light amount.
As described above, since the diffracted light L13 is diffracted in a direction different from that of the diffracted light L11, it is diffracted light that does not illuminate the illumination area, that is, diffracted light that does not enter the illumination area. In the present embodiment, it is assumed that the diffracted light L13 is first-order diffracted light.

  The area of the incident surface 12a of the second element 122 is set to a minimum value at which at least part of the diffracted light L13 generated by the second element 122 can be detected by the second photodetector 14. preferable. By setting it as such an area, the loss by which the light L10 is diffracted by the second element 122 can be minimized.

  The determination unit 15 calculates a relative value between the first detection value of the first photodetector 13 and the second detection value of the second photodetector 14, and calculates the relative value and the first detection value. Based on the change, it is determined whether or not the characteristics of the diffractive optical element 12 have changed. The relative value is “first detection value / second detection value” or “second detection value / first detection value”.

  Specifically, the determination unit 15 determines that the characteristic of the diffractive optical element has changed in the first case where the first detection value does not change and the relative value changes. Here, the “characteristics of the diffractive optical element” means the diffraction efficiency of the diffractive optical element.

  The light quantity of the regular reflection light L12 is determined by the light quantity of the incident light L10 and the refractive index of the diffractive optical element 12. Therefore, if the light amount of the light L10 is constant, the light amount of the regular reflection light L12 is substantially constant regardless of whether the characteristics of the diffractive optical element 12 have changed. That is, the first photodetector 13 detects the light amount of the light L10 incident on the diffractive optical element 12.

  Here, when the diffraction efficiency is reduced due to deterioration or deficiency of the second element 122 of the diffractive optical element 12, the light amount of the first-order diffracted light L13 is reduced. Accordingly, the second detection value is lowered. At this time, since the first detection value does not change as described above, the relative value of the first detection value and the second detection value changes.

  Therefore, as described above, it can be determined that the characteristics of the diffractive optical element 12 have changed, that is, have deteriorated. When the second element 122 is deteriorated or missing, it is highly likely that the first element 121 provided adjacent to the second element 122 is also deteriorated or missing due to secular change or the like. .

  In addition, in the second case where the first detection value decreases and the relative value does not change, the determination unit 15 does not change the characteristics of the diffractive optical element 12, that is, the diffraction efficiency, and the diffractive optical element 12 It is determined that the amount of the light L10 incident on the light has decreased. In this case, the second detection value is also decreased.

  Possible causes of the decrease in the amount of light L10 incident on the diffractive optical element 12 include, for example, a decrease in the amount of light emitted from the light source 11 or a change in the direction of the light source 11. Further, when a lens is provided between the light source 11 and the diffractive optical element 12, it is conceivable that the direction of the lens has changed.

  As described above, according to the present embodiment, the light amounts of the specularly reflected light L12 of the first element 121 and the first-order diffracted light L13 of the second element 122 are detected, and diffractive optics is based on these changes. It is determined whether or not the characteristics of the element 12 have changed. Therefore, it is possible to determine whether or not the characteristics of the diffractive optical element 12 have changed without adding optics other than the first and second photodetectors 13 and 14. That is, it is possible to determine whether or not the characteristics of the diffractive optical element 12 have changed with a simple configuration.

  Further, since the regular reflection light L12 and the first-order diffracted light L13 that are not used for illumination are detected, the loss of the diffracted light is minimized and the necessary diffracted light is used as the illumination light. It can be determined whether or not the characteristics of the diffractive optical element 12 have changed.

  Furthermore, since it is possible to specify which of the characteristics of the diffractive optical element 12 itself and the characteristics of the light source 11 has changed, it is possible to accurately determine whether the characteristics of the diffractive optical element 12 have changed.

  In addition, since the first element 121 and the second element 122 are provided adjacent to each other and have the same diffraction wavelength and the same incident angle for diffraction, it is not necessary to provide two light sources. It can be determined whether or not the characteristics of the diffractive optical element 12 have changed. That is, it does not require branch optics or another light source.

  Further, the incident surface 12a of the first element 121 and the incident surface 12a of the second element 122 constitute the same plane, or the second element 122 is laminated on the first element 121. Therefore, the diffractive optical elements having two types of diffraction performance, that is, the first and second elements 121 and 122 can be easily incorporated in one diffractive optical element 12.

  Various modifications can be made to the first embodiment. For example, the first photodetector 13 may detect specularly reflected light that is specularly reflected by the incident surface 12 a of the second element 122.

  Further, the diffracted light L13 detected by the second photodetector 14 is not limited to the first-order diffracted light, but may be diffracted light of another order such as a −1st-order diffracted light or a second-order diffracted light.

  Further, the diffracted light L11 having a predetermined order is not limited to the first-order diffracted light but may be diffracted light of another order such as a second-order diffracted light.

  Furthermore, at least one of the first element 121 and the second element 122 may be a transmissive diffractive optical element. However, in the stacked structure shown in FIG. 2C, the second element 122 is preferably a reflective diffractive optical element for the following reason. When the second element 122 is a transmission type and the first element 121 is a reflection type, the light diffracted by the second element 122 is incident on the first element 121, so that the incident angle changes and the first element 121 The diffracted light will be affected. Alternatively, when the diffracted light reflected by the first element 121 returns to the second element 122, it is also diffracted there, so that the diffracted light has another effect, and the light diffracted by the first element 121 is used. Efficiency may be reduced.

  Further, the position, number, and shape of the second element 122 are not limited to the example illustrated in FIG. For example, the second element 122 may be provided in a rectangular shape along one side of the first element 121. Depending on the usage situation, the end of the first element 121 has such a performance in the sense that the second element 122 is arranged at a position where the light diffracted by the first element 121 can be efficiently used. Good.

  Furthermore, an antireflection layer may be provided on at least one of the incident surface 12a and the back surface of the diffractive optical element 12. According to the antireflection layer on the incident surface 12a, the amount of light lost by reflection can be reduced. According to the antireflection layer on the back surface, the amount of light reflected to the light source 11 side on the back surface of the diffractive optical element 12 can be reduced. However, the antireflection layer on the incident surface 12a is capable of obtaining the regular reflection light L12 having a light quantity that can be detected by the first photodetector 13.

  Also, the first photodetector 13 and the second light detection are provided between the first photodetector 13 and the diffractive optical element 12 and between the second photodetector 14 and the diffractive optical element 12. A light amount adjustment filter for reducing the amount of light reaching the device 14 may be provided. As a result, the first and second photodetectors 13 and 14 having a low detectable maximum light amount can be used.

(Second Embodiment)
FIG. 3 is a diagram illustrating a schematic configuration of the illumination device 10a according to the second embodiment. As illustrated in FIG. 3, the lighting device 10 a further includes a control unit 16 in addition to the lighting device 10 of the first embodiment. Since the other configuration is the same as that of the first embodiment shown in FIGS. 1 and 2, the same components are denoted by the same reference numerals and description thereof is omitted.

  The control unit 16 is the same as the first case described in the first embodiment in which the first detection value does not change and the relative value changes, and the first detection value decreases and the relative value changes. In the second case, the light source 10 stops the emission of the light L10.

  Thereby, the emission of the light L10 can be stopped in the first case, that is, when the characteristics of the diffractive optical element 12 are changed, and in the second case, that is, when the characteristics on the light source 11 side are changed. , Can improve safety.

  For example, when the characteristics of the diffractive optical element 12 change, that is, when the diffraction efficiency decreases due to deterioration or defect of the diffractive optical element 12, the light amount of the first-order diffracted light L13 decreases and the zero-order diffracted light The amount of light increases. In this case, by stopping the emission of the light L10, it is possible to prevent the 0th-order diffracted light having an increased amount of light from continuing to be emitted.

  Further, for example, by stopping the emission of the light L10 when the characteristics on the light source 11 side change, it is possible to prevent the light L10 from continuing to be emitted in an unexpected direction due to the change in the direction of the light source 11.

  Note that if the characteristic change on the light source 11 side and the characteristic change of the diffractive optical element 12 are within the allowable ranges, whether or not the first detection value has decreased and the relative value does not stop the emission of the light L10. You may provide the threshold value for each determining whether it changed.

(Third embodiment)
FIG. 4 is a diagram illustrating a schematic configuration of the illumination device 10b according to the third embodiment. As shown in FIG. 4, the illuminating device 10b is further provided with the display part 17 in addition to the illuminating device 10a of 2nd Embodiment. Since other configurations are the same as those of the first and second embodiments of FIGS. 1 to 3, the same components are denoted by the same reference numerals and description thereof is omitted.

  The display unit 17 displays the first error information in the first case and the second error information in the second case in accordance with the control of the control unit 16. The display unit 17 may be provided in an operation unit (not shown) in which the user operates the operation of the lighting device 10b.

  The display unit 17 may display the first and second error information, for example, by turning on or blinking an error lamp. In this case, the first error information and the second error information may have different error lamp lighting patterns, lighting wavelengths, blinking cycles, and the like.

  Thus, the user can easily visually grasp whether the characteristic of the diffractive optical element 12 has changed or whether the characteristic on the light source 11 side has changed. Therefore, in a state where the light source 10 stops the emission of the light L10, the diffractive optical element 12 or the replacement or adjustment of the light source 11 is appropriately performed according to the displayed first or second error information. It can be carried out.

(Fourth embodiment)
This embodiment relates to a projection-type image display device using the illumination device 10a of the second embodiment.

  FIG. 5 is a diagram showing a schematic configuration of a projection display apparatus according to the fourth embodiment. As shown in FIG. 5, the projection display apparatus includes a projection device 100 and a screen 110.

  The projection device 100 includes an illumination device 10a, a lens group 18, a half-wave plate 20, a polarization beam splitter 30, a spatial light modulator 40, and a projection optical system 50. The projection device 100 has the same configuration as a known projection device except that the illumination device 10a includes first and second photodetectors 13 and 14, a determination unit 15, and a control unit 16. Therefore, detailed description of the same parts as those of the well-known projection apparatus is omitted.

  The lens group 18 is provided between the light source 11 and the diffractive optical element 12 of the illumination device 10a, spreads the light L10 emitted from the light source 11 to a desired diameter, and enters the incident surface 12a of the diffractive optical element 12.

  The diffractive optical element 12 diffracts the incident light L10 and illuminates the spatial light modulator 40 with the first-order diffracted light L11.

  Specifically, the half-wave plate 20 aligns the polarization components of the first-order diffracted light L11 from the diffractive optical element 12.

The polarization beam splitter 30 changes the traveling direction of the light from the half-wave plate 20 and guides it to the spatial light modulator 40. That is, the spatial light modulator 40 is illuminated by the illumination device 10a.
The spatial light modulator 40 includes, for example, LCOS (Liquid Crystal On Silicon), DMD (Digital Micromirror Device), and the like, and a modulated image is formed by the reflected light from the spatial light modulator 40.

The polarization beam splitter 30 guides the light to the projection optical system 50 without changing the traveling direction of the light forming the modulated image.
The projection optical system 50 projects a modulated image obtained on the spatial light modulator 40 onto the screen 110.

  According to such a projection apparatus 100, the state of the diffractive optical element 12 can be monitored in real time as described in the second embodiment while projecting a modulated image on the screen 110.

In addition, it may replace with the illuminating device 10a of 2nd Embodiment, and you may use the illuminating devices 10 and 10b of 1st or 3rd embodiment.
The illumination devices 10, 10a, and 10b of the first, second, and third embodiments are not limited to the projection device 100 configured as described above, and illuminate the spatial light modulator 40 with diffracted light from the diffractive optical element 12. The present invention can be applied to various projection apparatuses configured to do this.

  Furthermore, various apparatuses other than the projection apparatus and the projection display apparatus can be configured by using the illumination apparatuses 10, 10a, and 10b of the first, second, or third embodiment.

  For example, you may comprise the scanner provided with the illuminating device 10, 10a, 10b which illuminates a scan target object, and the information acquisition part which acquires surface information, such as the image of the illuminated scan target object.

In addition, the illumination devices 10, 10 a, and 10 b and the spatial light modulator illuminated by the illumination devices 10, 10 a, and 10 b are provided, and light modulated by the spatial light modulator is guided to the surface of the photosensitive medium. An exposure apparatus for manufacturing a semiconductor element may be configured. The spatial light modulator can form a modulated image (light image) having a fine pattern on a photosensitive medium by selecting and transmitting light for each pixel. The photosensitive medium is, for example, a semiconductor wafer coated with a resist pattern, a film coated with a photosensitive agent, or the like.
Also in these scanners and exposure apparatuses, the same effects as in the fourth embodiment can be obtained.

  The aspect of the present invention is not limited to the individual embodiments described above, and includes various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

10, 10a, 10b Illuminating device 11 Light source 12 Diffractive optical element 121 First element 122 Second element 13 First photodetector 14 Second photodetector 15 Determination unit 16 Control unit 17 Display unit

Claims (14)

A light source;
A diffractive optical element including a first element and a second element, wherein the first element diffracts light emitted from the light source, illuminates an illumination area with the diffracted light, and the second element A diffractive optical element that diffracts light emitted from the light source in a direction different from the diffraction direction of the first element;
A first photodetector for detecting at least part of the specularly reflected light reflected by the incident surface of the diffractive optical element;
A second photodetector for detecting at least part of the diffracted light generated by the second element of the diffractive optical element;
A relative value between the first detection value of the first photodetector and the second detection value of the second photodetector is calculated, and based on a change in the relative value and the first detection value. A determination unit for determining whether or not the characteristics of the diffractive optical element have changed,
A lighting device.   The lighting device according to claim 1, wherein the determination unit determines that the characteristic of the diffractive optical element has changed in the first case where the first detection value does not change and the relative value changes.   In the second case where the first detection value decreases and the relative value does not change, the determination unit does not change the characteristics of the diffractive optical element and is incident on the diffractive optical element. The lighting device according to claim 2, wherein it is determined that the amount of light has decreased.   The lighting device according to any one of claims 1 to 3, wherein the first element and the second element have the same incident angle of light from the light source and the same diffraction wavelength.   The area of the incident surface of the second element is set to a minimum value at which at least a part of the diffracted light generated by the second element can be detected by the second photodetector. The lighting device according to claim 4.   The illumination device according to any one of claims 1 to 5, wherein an incident surface of the first element and an incident surface of the second element constitute the same plane.   The lighting device according to claim 1, wherein the second element is stacked on the first element.   The illumination device according to claim 1, further comprising an antireflection layer on at least one of an incident surface and a back surface of the diffractive optical element.   Between the first photodetector and the diffractive optical element, and between the second photodetector and the diffractive optical element, the light reaching the first and second photodetectors The illumination device according to any one of claims 1 to 8, further comprising a light amount adjustment filter that reduces a light amount.   The lighting device according to claim 3, further comprising a control unit that causes the light source to stop emitting light in the first case and the second case.   The lighting device according to claim 10, further comprising: a display unit that displays first error information in the first case and displays second error information in the second case. A lighting device;
A spatial light modulator illuminated by the illumination device;
A projection optical system that projects a modulated image obtained on the spatial light modulator onto a screen;
With
The lighting device includes:
A light source;
A diffractive optical element including a first element and a second element, wherein the first element diffracts light emitted from the light source, illuminates the spatial light modulator with diffracted light, and The second element diffracts the light emitted from the light source in a direction different from the diffraction direction in the first element;
A first photodetector for detecting at least part of the specularly reflected light reflected by the incident surface of the diffractive optical element;
A second photodetector for detecting at least part of the diffracted light generated by the second element of the diffractive optical element;
A relative value between the first detection value of the first photodetector and the second detection value of the second photodetector is calculated, and based on a change in the relative value and the first detection value. A determination unit for determining whether or not the characteristics of the diffractive optical element have changed,
A projection device. An illumination device for illuminating a scan object;
An information acquisition unit that acquires surface information of the illuminated scan object;
With
The lighting device includes:
A light source;
A diffractive optical element including a first element and a second element, wherein the first element diffracts light emitted from the light source, illuminates the scan object with diffracted light, and The diffractive optical element diffracts the light emitted from the light source in a direction different from the diffraction direction in the first element;
A first photodetector for detecting at least part of the specularly reflected light reflected by the incident surface of the diffractive optical element;
A second photodetector for detecting at least part of the diffracted light generated by the second element of the diffractive optical element;
A relative value between the first detection value of the first photodetector and the second detection value of the second photodetector is calculated, and based on a change in the relative value and the first detection value. A determination unit for determining whether or not the characteristics of the diffractive optical element have changed,
Having a scanner. A lighting device;
A spatial light modulator illuminated by the illumination device,
The light modulated by the spatial light modulator is guided to the surface of the photosensitive medium,
The lighting device includes:
A light source;
A diffractive optical element including a first element and a second element, wherein the first element diffracts light emitted from the light source, illuminates the spatial light modulator with diffracted light, and The second element diffracts the light emitted from the light source in a direction different from the diffraction direction in the first element;
A first photodetector for detecting at least part of the specularly reflected light reflected by the incident surface of the diffractive optical element;
A second photodetector for detecting at least part of the diffracted light generated by the second element of the diffractive optical element;
A relative value between the first detection value of the first photodetector and the second detection value of the second photodetector is calculated, and based on a change in the relative value and the first detection value. A determination unit for determining whether or not the characteristics of the diffractive optical element have changed,
An exposure apparatus.

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