Driving method, light source unit, illumination unit, exposure device, and exposure method

Abstract

A method for driving a light source element, wherein if a first current value is supplied when the temperature of the light source element is within a first temperature range, the light source element emits light with a first luminous intensity. The method for driving the aforementioned light source element includes: when the aforementioned light source element is in a state of emitting light with the aforementioned first luminous intensity, supplying current to the aforementioned light source element with a second current value lower than the aforementioned first current value; and increasing the current value supplied to the aforementioned light source element from the aforementioned second current value to the aforementioned first current value.

Description

Drive method, light source unit, illumination unit, exposure device, and exposure method Regarding a drive method, a light source unit, an illumination unit, an exposure device, and an exposure method. In recent years, as a display element for personal computers or televisions, liquid crystal display panels have been widely used. A liquid crystal display panel is manufactured by forming a circuit pattern of thin film transistors on a plate body (glass substrate) by a lithography technique. As a device for performing this lithography process, an exposure device that projects and exposes the original drawing pattern formed on a photomask onto a photoresist layer on a plate body via a projection optical system is used (for example, refer to Patent Document 1). In a light source used in various optical devices including the above exposure device, it is required to stabilize the light emission amount. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-207251 [Problems to be Solved by the Invention] According to a first aspect of the disclosure, a drive method for a light source element, which is a drive method for a light source element that emits light with a first light emission amount when a current of a first current value is supplied while the temperature of the light source element is within a first temperature range, includes: when making the light source element emit light with the first light emission amount, starting to supply a current to the light source element with a second current value lower than the first current value; increasing the current value of the current supplied to the light source element from the second current value to the first current value. According to a second aspect of the disclosure, a light source unit includes: a plurality of light source elements two-dimensionally arranged on the surface of a fixed object, each of which emits light with a first light emission amount when a current of a first current value is supplied while its temperature is within a first temperature range; a control unit that controls the value of the current supplied to the plurality of light source elements; the control unit starts to supply a current to the plurality of light source elements with a second current value lower than the first current value when making the plurality of light source elements emit light with the first light emission amount, and increases the current value of the current supplied to the plurality of light source elements from the second current value to the first current value. According to a third aspect of the disclosure, an illumination unit includes: a light source unit as described above; an illumination optical system that guides the light emitted from the light source unit to an object to be irradiated. According to a fourth aspect of the disclosure, an exposure device includes: an illumination unit as described above; a projection optical system that projects the pattern image of a photomask illuminated by the illumination unit onto a photosensitive substrate. According to a fifth aspect of the disclosure, an exposure method is an exposure method using the exposure device as described above, including: illuminating a photomask by the illumination unit, and projecting the pattern image of the photomask onto a photosensitive substrate using the projection optical system. According to the aspect disclosed in the sixth aspect, a driving method for a light source element, which is a driving method for a light source element that emits light with a first light emission amount when a current with a first current value is supplied, includes: when the light source element is in a state of emitting light with the first light emission amount, supplying a current with a second current value lower than the first current value to the light source element; increasing the current value of the current supplied to the light source element from the second current value to the first current value. In addition, the configuration of the following embodiments can be appropriately improved. Furthermore, at least a part can be replaced with other components. In addition, for components whose configuration is not particularly limited, they are not limited to the configuration disclosed in the embodiments and can be arranged at positions where their functions can be achieved. Regarding the exposure apparatus 10 of an embodiment, it will be described based on FIGS. 1 to 12. (Configuration of the exposure apparatus) First, the configuration of the exposure apparatus 10 of this embodiment will be described. FIG. 1 is a diagram schematically showing the configuration of the exposure apparatus 10 of this embodiment. The exposure apparatus 10 is a scanning stepper (scanner) that transfers the pattern formed on the mask MSK onto the plate body P by driving the mask MSK and the glass substrate (hereinafter referred to as "plate body") P in the same direction at the same speed relative to the projection optical system PL. The plate body P is, for example, a rectangular glass substrate used in a liquid crystal display device (flat panel display), and the length of at least one side or the diagonal length is 500 mm or more. In the following content, the direction in which the mask MSK and the plate body P are driven during scanning exposure (scanning direction) is the X-axis direction, the direction in the horizontal plane orthogonal to this direction is the Y-axis direction, the direction orthogonal to the X-axis direction and the Y-axis direction is the Z-axis direction, and the rotation (tilt) directions around the X-axis, Y-axis, and Z-axis are the θx, θy, and θz directions, respectively. The exposure apparatus 10 includes an illumination system IOP, a mask stage MST that holds the mask MSK, a projection optical system PL, a main body 70 that supports the above-mentioned components, a substrate stage PST that holds the plate body P, and a control system for the above-mentioned components, etc. The control system controls each part of the configuration of the exposure apparatus 10 as a whole. The main body 70 includes a base (vibration isolation table) 71, support columns 72A and 72B, an optical table 73, a support body 74, and a sliding guide 75. The base (vibration isolation table) 71 is disposed on the ground F and supports the support columns 72A, 72B, etc. after removing the vibration from the ground F. The support columns 72A and 72B respectively have a frame shape, and the support column 72A is disposed inside the support column 72B. The optical table 73 has a flat plate shape and is fixed to the ceiling portion of the support column 72A. The support body 74 is supported on the ceiling portion of the support column 72B via the sliding guide 75. The sliding guide 75 includes a balloon lifter and a positioning mechanism, and positions the support body 74 (i.e., the mask stage MST described later) at an appropriate position in the X-axis direction relative to the optical table 73. The illumination system IOP is disposed above the main body 70. The illumination system IOP irradiates the illumination light IL onto the mask MSK. The detailed configuration of the illumination system IOP will be described later. The mask stage MST is supported by the support body 74. On the mask stage MST, a mask MSK having a pattern surface (the lower surface in FIG. 1) formed with a circuit pattern is fixed, for example, by vacuum adsorption (or electrostatic adsorption). The mask stage MST is driven, for example, by a drive system including a linear motor with a predetermined stroke in the scanning direction (X-axis direction), and is slightly driven in the non-scanning directions (Y-axis direction and θz direction). The position information (including the rotation information in the θz direction) in the XY plane of the mask stage MST is measured by an interferometer system. The interferometer system irradiates a length measurement beam onto a moving mirror (or a mirror surface processed reflection surface (not shown)) provided at the end of the mask stage MST, and measures the position of the mask stage MST by receiving the reflected light from the moving mirror. The measurement result is supplied to a control device (not shown), and the control device drives the mask stage MST via the drive system according to the measurement result of the interferometer system. The projection optical system PL is disposed below the mask stage MST (-Z side) and is supported by the optical table 73. The projection optical system PL is configured, for example, in the same manner as the projection optical system disclosed in the specification of U.S. Patent No. 5,729,331, and includes a plurality of (e.g., 7) projection optical units 100 (multi-lens projection optical units) arranged in a staggered manner in the projection area of the pattern image of the mask MSK, and forms an image field in a rectangular shape with the Y-axis direction as the length direction. Here, four projection optical units 100 are arranged at a predetermined interval in the Y-axis direction, and the remaining three projection optical units 100 are separated from the four projection optical units 100 toward the +X side and are arranged at a predetermined interval in the Y-axis direction. Each of the plurality of projection optical units 100 is used, for example, to form an erect and positive image with an equal magnification system having telecentricity on both sides. In addition, the plurality of projection areas of the projection optical units 100 arranged in a staggered manner are collectively referred to as the exposure area. When illuminating the illumination area on the reticle MSK with the illumination light IL from the illumination system IOP, through the illumination light IL passing through the reticle MSK, via the projection optical system PL, the projected image (partial erect image) of the circuit pattern of the reticle MSK in the illumination area is formed on the irradiation area (exposure area (conjugate to the illumination area)) on the plate body P disposed on the image plane side of the projection optical system PL. Here, a photoresist (sensitizer) is coated on the surface of the plate body P. By synchronously driving the reticle stage MST and the substrate stage PST, that is, driving the reticle MSK relative to the illumination area (illumination light IL) in the scanning direction (X-axis direction), and driving the plate body P relative to the exposure area (illumination light IL) in the same scanning direction, the plate body P is exposed and the pattern of the reticle MSK is transferred onto the plate body P. The substrate stage PST is disposed on the base (vibration isolation table) 71 below ( -Z side) the projection optical system PL. On the substrate stage PST, the plate body P is held via a substrate holder (not shown). The position information (including rotation information (yaw amount (rotation amount θz in the θz direction), pitch amount (rotation amount θx in the θx direction), roll amount (rotation amount θy in the θy direction))) in the XY plane of the substrate stage PST is measured by an interferometer system. The interferometer system irradiates a length measurement beam from the optical bench 73 to a moving mirror (or a mirror surface processed reflecting surface (not shown)) provided at the end of the substrate stage PST, and measures the position of the substrate stage PST by receiving the reflected light from the moving mirror. The measurement result is supplied to a control device (not shown), and the control device drives the substrate stage PST according to the measurement result of the interferometer system. In the exposure apparatus 10, before exposure, alignment measurement (for example, EGA, etc.) is performed, and using the result, the plate body P is exposed in the following process. First, according to the instruction of the control device, the reticle stage MST and the substrate stage PST are synchronously driven in the X-axis direction. Thereby, scanning exposure to the first irradiation area on the plate body P is performed. When the scanning exposure to the first irradiation area ends, the control device moves (steps) the substrate stage PST to the position corresponding to the second irradiation area. Thereafter, scanning exposure to the second irradiation area is performed. Similarly, the control device repeats the stepping between the irradiation areas of the plate body P and the scanning exposure to the irradiation areas, and transfers the pattern of the reticle MSK to all the irradiation areas on the plate body P. (Configuration of the illumination system IOP) Next, the configuration of the illumination system IOP in this embodiment will be described. The illumination system IOP includes a plurality of illumination units 90 corresponding to each of the plurality of projection optical units 100 included in the projection optical system PL. FIG. 2 is a diagram schematically showing the configuration of the illumination unit 90. As shown in FIG. 2, the illumination unit 90 includes a first light source unit OPU1, a second light source unit OPU2, and an illumination optical system 80. (Configuration of the light source unit) The first light source unit OPU1 includes a first light source array 20A, a first magnification optical system 30A, and a first control unit CTR1. The second light source unit OPU2 includes a second light source array 20B, a second magnification optical system 30B, and a second control unit CTR2. FIG. 3(A) is a plan view schematically showing the configuration of the first light source array 20A and the second light source array 20B. The first light source array 20A includes, for example, a plurality (5×5 in FIG. 3(A)) of LED (Light Emitting Diode) chips 23A arranged on a substrate 21A. The number of LED chips 23A can be appropriately changed as needed. The plurality of LED chips 23A each have a light emitting portion 231A, and the peak wavelength of the light emitted from the light emitting portion 231A is in the range of 380 to 390 nm. That is, the light emitting portion 231A is an ultraviolet LED (UV LED). The peak wavelength of the light emitted from the light emitting portion 231A is preferably 385 nm. The light emitting surface of the light emitting portion 231A is square, and the length of one side is a1. The LED chips 23A are arranged at a pitch P1. The pitch P1 is the distance between the centers of adjacent LED chips 23A. The second light source array 20B includes, for example, a plurality (5×5 in FIG. 3(A)) of LED chips 23B arranged on a substrate 21B. The number of LED chips 23B can be appropriately changed as needed. The plurality of LED chips 23B each have a light emitting portion 231B, and the peak wavelength of the light emitted from the light emitting portion 231B is in the range of 360 to 370 nm. That is, the light emitting portion 231B is a UV LED. The peak wavelength of the light emitted from the light emitting portion 231B is preferably 365 nm. The light emitting surface of the light emitting portion 231B is square, and the length of one side is a2. The LED chips 23B are arranged at a pitch P2. The pitch P1 of the LED chips 23A and the pitch P2 of the LED chips 23B can be the same or different. In addition, the length a1 of one side of the light emitting surface of the light emitting portion 231A and the length a2 of one side of the light emitting surface of the light emitting portion 231B can be the same or different. Further, the LED chips 23A and the LED chips 23B may be arranged not on a substrate but, for example, on a heat sink. FIG. 3(B) is a diagram schematically showing the internal configurations of the first light source unit OPU1 and the second light source unit OPU2. In addition, since the internal configurations of the first light source unit OPU1 and the second light source unit OPU2 are the same, the configuration of the first light source unit OPU1 will be mainly described herein. Here, the two directions in which the LED chips 23A are arranged are the X1 direction and the Y1 direction. The X1 direction is orthogonal to the Y1 direction. In addition, the direction orthogonal to the X1 direction and the Y1 direction is the Z1 direction. The Z1 direction is substantially parallel to the optical axis OA of the light emitted from the light emitting portion 231A. In FIG. 3(B), for clarity of the drawing, only 4 LED chips 23A arranged in a row along the Y1 direction are shown. As shown in FIG. 3(B), the first magnification optical system 30A is a magnification optical system for respectively forming magnified images of the light emitting portions 231A of the respective LED chips 23A on a predetermined plane PP. The first magnification optical system 30A includes a plurality of lens portions 31A arranged corresponding to the arrangement of the LED chips 23A. Each lens portion 31A is a two-sided telecentric optical system that magnifies and projects the light emitting portion 231A at a magnification M1 of (pitch P1 of the LED chip 23B) / (length a1 of one side of the light emitting surface of the light emitting portion 231A) or more. The second magnification optical system 30B is a magnification optical system for respectively forming magnified images of the light emitting portions 231B of the respective LED chips 23B on a predetermined plane PP. The second magnification optical system 30B includes a plurality of lens portions 31B arranged corresponding to the arrangement of the LED chips 23B. Each lens portion 31B is a two-sided telecentric optical system that magnifies and projects the light emitting portion 231B at a magnification M2 of (pitch P2 of the LED chip 23A) / (length a2 of one side of the light emitting surface of the light emitting portion 231B) or more. In the present embodiment, each of the lens portion 31A and the lens portion 31B includes 4 plano-convex lenses, but is not limited thereto. For example, each of the lens portion 31A and the lens portion 31B may include 2 biconvex lenses, or may include 3 biconvex lenses. In addition, for example, each of the lens portion 31A and the lens portion 31B may include a plano-convex lens and a biconvex lens. The first control unit CTR1 controls the current value of the current supplied to the LED chips 23A included in the first light source array 20A. The second control unit CTR2 controls the current value of the current supplied to the LED chips 23B included in the second light source array 20B. FIG. 4 is a diagram illustrating the relationship between the temperatures of LED chips 23A and 23B and the light emission amounts of light emitting portions 231A and 231B. As shown in FIG. 4, for the light emitting portions 231A and 231B of the LED chips 23A and 23B, when the temperatures of the LED chips 23A and 23B are within the range of temperature T1 to temperature T2 (> T1) (first temperature range), if a current of a first current value CV1 is supplied, light is emitted with a first light emission amount LA1. The first temperature range is, for example, 20°C to 90°C, and may also be 20°C to 50°C. In addition, for the light emitting portions 231A and 231B of the LED chips 23A and 23B, when the temperatures of the LED chips 23A and 23B are within the range of temperature T3 to temperature T4 (> T3) (second temperature range), if a current of a third current value CV3 lower than the first current value CV1 is supplied, light is emitted with a second light emission amount LA2. Additionally, temperature T3 is lower than temperature T1, and temperature T4 is lower than temperature T2. In the present embodiment, when the first control unit CTR1 causes the light emitting portion 231A of the LED chip 23A in a state where the temperature is lower than the temperature T1 and no current is supplied to emit light with the first light emission amount LA1, the current supply to the LED chip 23A starts with a second current value CV2 lower than the first current value CV1. In addition, when the second control unit CTR2 causes the light emitting portion 231B of the LED chip 23B in a state where the temperature is lower than the temperature T1 and no current is supplied to emit light with the first light emission amount LA1, the current supply to the LED chip 23B starts with a second current value CV2 lower than the first current value CV1. Thereby, the time until the light emitting portions 231A and 231B of the LED chips 23A and 23B reach stable light emission with the first light emission amount LA1 can be shortened. This will be described in detail. In addition, in the present embodiment, the so-called "the light emitting portion 231A of the LED chip 23A stably emits light with the first light emission amount LA1" means that, with respect to the first light emission amount LA1, the ratio of the difference ΔLAt (= LAt - LA1) between the light emission amount LAt at a certain time point t after the start of the current supply to the LED chip 23A and the first light emission amount LA1 (referred to as the light emission amount deviation rate), that is, ΔLAt / LA1 × 100 [%] is within the range of ±1%. The reason is that in the situation where the light emission amount deviation rate is within the range of ±1%, the difference in the light emission amount of the light emitting portion 231A of the LED chip 23A does not affect the exposure. As a first comparative example, a case will be described in which when the light emitting portion 231A of the LED chip 23A of the first light source array 20A in a state where the temperature is lower than the temperature T1 and no current is supplied is caused to emit light with the first light emission amount LA1, the current is supplied to the LED chip 23A with the first current value CV1 from the start of the current supply. FIG. 5(A) is a chart showing the measurement results of the light emission amount of the light emitting portion 231A of the LED chip 23A in Comparative Example 1. In FIG. 5(A), the vertical axis represents the light emission amount deviation rate, and the horizontal axis represents the elapsed time from the start of current supply. FIG. 5(B) is a chart obtained by magnifying the range of the light emission amount deviation rate of 0% to 2% on the vertical axis in FIG. 5(A). FIG. 6 is a diagram showing the output with respect to the elapsed time in Comparative Example 1. The output [%] is the ratio of the current value CVt of the current supplied to the LED chip 23A at a certain time point t to the first current value CV1 (output [%] = CVt / CV1 × 100). As shown in FIG. 6, in Comparative Example 1, the output is 100% and fixed from the start of current supply. That is, in Comparative Example 1, current is supplied to the LED chip 23A at the first current value CV1 from the start of current supply. As shown in FIG. 5(A), when current supply to the LED chip 23A is started at the first current value CV1, the light emitting portion 231A of the LED chip 23A emits light with a light emission amount higher than the first light emission amount LA1, and the light emission amount decreases with the passage of time. This phenomenon is because the light emission amount of the light emitting portion 231A provided in the LED chip 23A decreases as the temperature of the LED chip 23A rises. More specifically, at the time point when current supply to the LED chip 23A is started, since the temperature of the LED chip 23A is low, the light emission amount of the light emitting portion 231A of the LED chip 23A is high. Thereafter, the light emission amount decreases as the temperature of the LED chip 23A rises. Thereafter, at the time point when about 80 seconds have elapsed from the start of current supply, the light emission amount of the light emitting portion 231A of the LED chip 23A becomes stable within the range of the light emission amount deviation rate of ±1%. FIG. 7(A) is a chart showing the measurement results of the light emission amount of the light emitting portion 231A of the LED chip 23A in the present embodiment, and FIG. 7(B) is a chart obtained by magnifying the range of the light emission amount deviation rate of 0% to 2% in FIG. 7(A). In addition, FIG. 8(A) is a diagram showing the output of the first control unit CTR1 with respect to the elapsed time in the present embodiment, and FIG. 8(B) is a chart obtained by magnifying the range of the output of 98% to 100% in FIG. 8(A). As shown in FIG. 8(A), in the present embodiment, the first control unit CTR1 starts current supply with an output current lower than 100%, and increases the output with the passage of time. That is, current supply to the LED chip 23A is started with a second current value CV2 lower than the first current value CV1 (in FIG. 8(A), a current value of about 89% of the first current value CV1), and the current value of the current supplied to the LED chip 23A is increased with the passage of time. Thus, as shown in FIGS. 7(A) and 7(B), the luminous flux deviation rate is within the range of ±1% from the start of current supply. That is, the current value of the current supplied to the LED chip 23A emits light with a first luminous flux LA1 before the current value of the current supplied to the LED chip 23A changes from the second current value CV2 to the first current value CV1. This phenomenon is considered to be because when the temperature of the LED chip 23A is low, the first luminous flux LA1 can be obtained with a current value lower than the first current value CV1. By increasing the current value corresponding to the temperature rise of the LED chip 23A, the current value suitable for obtaining the first luminous flux LA1 at each temperature can be supplied to the LED chip 23A. After the current value of the current supplied to the LED chip 23A becomes the first current value CV1, the LED chip 23A continues to emit light with the first luminous flux LA1. How to increase the output (the current value of the current supplied to the LED chip 23A) can be determined from the change in the luminous flux deviation rate obtained when starting to supply current to the LED chip 23A at the first current value CV1 (FIGS. 5(A) and 5(B)). For example, in the case of the change in the luminous flux deviation rate shown in FIGS. 5(A) and 5(B), the slope of the luminous flux deviation rate between the elapsed time t1 and the elapsed time t2 can be obtained from the luminous flux deviation rate at the elapsed time t1 and the luminous flux deviation rate at the elapsed time t2, and the increase ratio (increase amount) of the output between the elapsed time t1 and the elapsed time t2 can be determined based on this slope. Alternatively, it is also possible to increase the output at a certain ratio based on the value obtained by dividing the time from the start of current supply until the luminous flux deviation rate enters the range of ±1% by the change amount of the luminous flux deviation rate (the average slope of the luminous flux deviation rate). In this embodiment, the slope of the luminous flux deviation rate in adjacent measurement times is obtained, and the increase ratio of the output is determined from this slope of the luminous flux deviation rate. Therefore, the shapes of the output charts shown in FIGS. 8(A) and 8(B) are the shapes obtained by flipping the shapes of the luminous flux deviation rate charts shown in FIGS. 5(A) and 5(B) up and down, respectively. As described above, by starting to supply current to the LED chip 23A with a second current value CV2 lower than the first current value CV1 (for example, a current value of about 89% of the first current value CV1) and increasing the current value of the current supplied to the LED chip 23A over time, the time until the light emitting portion 231A of the LED chip 23A stably emits light with the first luminous flux LA1 can be shortened. In addition, although the light emitting portion 231A of the LED chip 23A has been described, the same applies to the light emitting portion 231B of the LED chip 23B. In addition, for example, based on the luminous flux deviation rate (refer to FIG. 7(A)) achieved by changing the output as shown in FIG. 8(A), the first control unit CTR1 further corrects the output. In this case, as long as the luminous flux deviation rate shown in FIG. 7(A) is reflected in the output shown in FIG. 8(A) to create a chart of the new output, the first control unit CTR1 can change the output based on this chart of the new output. Thereby, the time until the light emitting portion 231A of the LED chip 23A emits light stably at the first luminous flux LA1 can be further shortened. The correction of the output based on the luminous flux deviation rate can also be performed multiple times. In addition, the first control unit CTR1 can also perform machine learning using the data of the luminous flux deviation rate and the output data as teacher data, and use the obtained learned model to determine the output. Next, a case where the light emitting portion 231A of the LED chip 23A that is supplied with the first current value CV1 and emits light at the first luminous flux LA1 is caused to emit light at a second luminous flux LA2 lower than the first luminous flux LA1 will be described. As described above, when the temperature of the LED chip 23A is within the range of temperature T3 to temperature T4 (second temperature range), the light emitting portion 231A of the LED chip 23A emits light at the second luminous flux LA2 when a current of a third current value CV3 lower than the first current value CV1 is supplied (refer to FIG. 4). In this case, the first control unit CTR1 reduces the current value of the current supplied to the LED chip 23A from the first current value CV1 to the third current value CV3. More specifically, the current value of the current supplied to the LED chip 23A is reduced from the first current value CV1 to the third current value CV3 over time. Thereby, the time until the light emitting portion 231A of the LED chip 23A emits light stably at the second luminous flux LA2 can be shortened. This will be described. In addition, in this embodiment, the so-called "the light emitting portion 231A of the LED chip 23A emits light stably at the second luminous flux LA2" means that the ratio of the difference ΔLAt (= LAt - LA2) between the luminous flux LAt at a certain time point t and the second luminous flux LA2 with respect to the second luminous flux LA2 (referred to as the luminous flux deviation rate), that is, ΔLAt / LA2 × 100 [%] is within the range of ± 1%. As Comparative Example 2, a case where, when the light emitting portion 231A of the LED chip 23A that is supplied with the current of the first current value CV1 and emits light at the first luminous flux LA1 is caused to emit light at the second luminous flux LA2, the current value of the current supplied to the LED chip 23A is immediately changed from the first current value CV1 to the third current value CV3 will be described. FIG. 9(A) is a chart showing the simulation result of the luminous flux of the light-emitting part 231A of the LED chip 23A in Comparative Example 2. FIG. 9(B) is a chart obtained by magnifying the range of the luminous flux deviation rate from -2% to 0% and the elapsed time from 0 second to 50 seconds in FIG. 9(A). In FIG. 9(A), the vertical axis represents the luminous flux deviation rate, and the horizontal axis represents the elapsed time from the start of the control for changing the luminous flux of the light-emitting part 231A of the LED chip 23A from the first luminous flux LA1 to the second luminous flux LA2. The luminous flux deviation rate in FIG. 9(A) is the ratio (=ΔLAt / LA2) of the difference ΔLAt (=LAt - LA2) between the luminous flux LAt at the elapsed time t with respect to the second luminous flux LA2 and the second luminous flux LA2. FIG. 10 is a chart showing the output with respect to the elapsed time in Comparative Example 2. In addition, the third current value CV3 is assumed to be a current value that is 50% of the first current value CV1. Therefore, the so-called output of 50% means that the current value of the current supplied to the LED chip 23A is the third current value CV3. As shown in FIG. 9(B), in Comparative Example 2, the output with respect to the elapsed time is maintained at 50%. That is, in Comparative Example 2, immediately after the control for changing the luminous flux of the light-emitting part 231A of the LED chip 23A from the first luminous flux LA1 to the second luminous flux LA2 is started, the current is supplied to the LED chip 23A at the third current value CV3. When the current value supplied to the LED chip 23A is immediately changed from the first current value CV1 to the third current value CV3, as shown in FIG. 9(A), the light-emitting part 231A of the LED chip 23A emits light with a luminous flux lower than the second luminous flux LA2, and the luminous flux increases with the passage of time. This phenomenon is because at the time point when the current supply to the LED chip 23A is started at the third current value CV3, the temperature of the LED chip 23A is higher than the temperature T4, so the luminous flux of the light-emitting part 231A of the LED chip 23A becomes lower. Thereafter, the luminous flux increases as the temperature of the LED chip 23A decreases. Thereafter, at the time point when about 6 seconds have elapsed after the current value supplied to the LED chip 23A is made the third current value CV3, within the range where the luminous flux deviation rate becomes ±1%, the luminous flux of the light-emitting part 231A of the LED chip 23A becomes stable. FIG. 11(A) is a chart showing the simulation result of the luminous flux of the light-emitting part 231A of the LED chip 23A in this embodiment. FIG. 11(B) is a chart obtained by magnifying the range of the luminous flux deviation rate from -2% to 0% and the elapsed time from 0 second to 50 seconds. In addition, FIG. 12 is a chart showing the output of the first control unit CTR1 with respect to the elapsed time in this embodiment. In the present embodiment, when the first control unit CTR1 starts to control the light emission amount of the light emitting unit 231A of the LED chip 23A to change from the first light emission amount LA1 to the second light emission amount LA2, the current value of the current supplied to the LED chip 23A is made lower than the first current value CV1 and higher than the third current value CV3, and the current value of the current supplied to the LED chip 23A is decreased to the third current value CV3 over time. For example, the first control unit CTR1 makes the current value 1 / 10 second after starting to control the light emission amount of the light emitting unit 231A of the LED chip 23A to change from the first light emission amount LA1 to the second light emission amount LA2 be about 56% of the first current value CV1, and makes the current value 2 / 10 second after be about 55% of the first current value CV1. As described above, in the present embodiment, when the first control unit CTR1 starts to control the light emission amount of the light emitting unit 231A of the LED chip 23A to change from the first light emission amount LA1 to the second light emission amount LA2, a current with a value lower than the first current value CV1 and higher than the third current value CV3 is supplied to the LED chip 23A, and the current value is decreased over time. Thereby, as shown in FIGS. 11(A) and 11(B), the light emission amount deviation rate is within the range of ±1% from the start of the control for changing the light emission amount of the light emitting unit 231A of the LED chip 23A from the first light emission amount LA1 to the second light emission amount LA2. This phenomenon is considered to be because at the start of the control, the temperature of the LED chip 23A is higher than the temperature T4 and the light emission efficiency of the LED chip 23A is low, the second light emission amount LA2 can be obtained with a current value higher than the third current value CV3, and by decreasing the current value in correspondence with the decrease in the temperature of the LED chip 23A, a current with a current value suitable for obtaining the second light emission amount LA2 can be supplied to the LED chip 23A at each temperature. How to decrease the output (the current value of the current supplied to the LED chip 23A) can be determined from the change in the light emission amount deviation rate obtained when supplying a current to the LED chip 23A at the third current value CV3 from the start of the control for making the light emission amount of the light emitting unit 231A of the LED chip 23A be the second light emission amount LA2 (FIGS. 9(A) and 9(B)). For example, in the case of the change in the light emission amount deviation rate shown in FIG. 9(A), the slope of the light emission amount deviation rate between the elapsed time t1 from the start of control and the light emission amount deviation rate at the elapsed time t2 can be obtained from the light emission amount deviation rate at the elapsed time t1 and the light emission amount deviation rate at the elapsed time t2. Based on this slope, the reduction ratio (reduction amount) of the output between the elapsed time t1 and the elapsed time t2 is determined. Alternatively, it is also possible to reduce the output by a certain ratio based on the value obtained by dividing the time from the start of control until the light emission amount deviation rate enters the range of ±1% by the change amount of the light emission amount deviation rate (average slope of the light emission amount deviation rate). In the present embodiment, the slope of the light emission amount deviation rate in adjacent measurement times is obtained, and the reduction ratio of the output is determined from the slope of the light emission amount deviation rate. Therefore, the shape of the output chart shown in FIG. 12 is the shape obtained by flipping the shape of the light emission amount deviation rate chart shown in FIG. 9(A) upside down respectively. As described above, in the case where the light emitting portion 231A of the LED chip 23A is changed from the state of emitting light with the first light emission amount LA1 to the state of emitting light with the second light emission amount LA2 (< the first light emission amount LA1), at the start of control, a current with a value lower than the first current value CV1 and higher than the third current value CV3 is supplied to the LED chip 23A, and the current value of the current supplied to the LED chip 23A is decreased to the third current value CV3 over time, so that the time until the light emitting portion 231A of the LED chip 23A stably emits light with the second light emission amount LA2 can be shortened. In addition, although the light emitting portion 231A of the LED chip 23A has been described, the same applies to the light emitting portion 231B of the LED chip 23B. In addition, for example, the first control unit CTR1 can further correct the output based on the light emission amount deviation rate (refer to FIG. 11(A)) achieved by changing the output as shown in FIG. 12. In this case, as long as the light emission amount deviation rate shown in FIG. 11(A) is reflected in the output shown in FIG. 12 to create a new output chart, and the output is changed by the first control unit CTR1 based on this new output chart. Thereby, the time until the light emission amount of the light emitting portion 231A of the LED chip 23A becomes stable can be further shortened. The correction of the output based on the light emission amount deviation rate can also be performed multiple times. In addition, the first control unit CTR1 can also perform machine learning using the light emission amount deviation rate data and the output data as teacher data, and use the obtained learned model to determine the output. (Configuration of the illumination optical system 80) Referring again to FIG. 2, the configuration of the illumination optical system 80 will be described. The illumination optical system 80 includes a first condenser optical system 81A including a first dichroic mirror DM1, a second condenser optical system 81B, a second dichroic mirror DM2, an imaging optical system 83, a fly-eye lens FEL, an aperture stop 85, and a condenser optical system 84. The first condenser optical system 81A forms the pupil of the magnified image of the light emitting part 231A formed by the first magnifying optical system 30A. That is, the rear focal point position of the first condenser optical system 81A becomes the position of the pupil. The first condenser optical system 81A has a first dichroic mirror DM1 in the middle of the optical path, which reflects at least a part of the light with a peak wavelength of 385 nm. Thereby, the light beam is incident on the second dichroic mirror DM2. In addition, the first condenser optical system 81A may be configured without the first dichroic mirror DM1. In this case, it is only necessary to appropriately adjust the arrangement of the first light source unit OPU1 and the lenses of the first condenser optical system 81A so that the light beam is incident on the second dichroic mirror DM2. Furthermore, the first condenser optical system 81A may be composed of a single lens or a lens group including a plurality of lenses. The second condenser optical system 81B forms the pupil of the magnified image of the light emitting part 231B formed by the second magnifying optical system 30B. That is, the rear focal point position of the second condenser optical system 81B becomes the position of the pupil. The second condenser optical system 81B may be composed of a single lens or a lens group including a plurality of lenses. The second dichroic mirror DM2 transmits at least a part of the light with a peak wavelength of 385 nm and reflects at least a part of the light with a peak wavelength of 365 nm. Thereby, a combined image is formed by overlapping the pupil image formed by the first condenser optical system 81A and the pupil image formed by the second condenser optical system 81B. In this embodiment, the second dichroic mirror DM2 overlaps the pupil image formed by the first condenser optical system 81A and the pupil image formed by the second condenser optical system 81B to form a combined image. That is, the second dichroic mirror DM2 is arranged at a position that is both the rear focal point position of the first condenser optical system 81A and the rear focal point position of the second condenser optical system 81B. Thereby, the second dichroic mirror DM2 performs Köhler illumination on the light emitted from the first light source unit OPU1 and the light emitted from the second light source unit OPU2. By Köhler illumination, the change in the illuminance of the light beam of the pupil image formed by the first condenser optical system 81A and the change in the illuminance of the light beam of the pupil image formed by the second condenser optical system 81B can be made smaller. In addition, not limited to the configuration of this embodiment, the first condenser optical system 81A and the second condenser optical system 81B may also be configured to perform critical lighting in which an image of the first light source unit OPU1 and an image of the second light source unit OPU2 are respectively formed on the second dichroic mirror DM2. In the illumination unit 90, a detector DT10 for monitoring light with a peak wavelength of 385 nm, a detector DT20 for monitoring light with a peak wavelength of 365 nm, and a detector DT30 for monitoring light with a peak wavelength of 385 nm and light with a peak wavelength of 365 nm are provided. Specifically, the detector DT10 detects the illuminance of light with a peak wavelength of 385 nm reflected by the first dichroic mirror DM1. The detector DT20 detects the illuminance of light with a peak wavelength of 365 nm reflected by the second dichroic mirror DM2. The detector DT30 detects the illuminance of 385 nm light accidentally reflected by the second dichroic mirror DM2 and the illuminance of 365 nm light accidentally transmitted through the second dichroic mirror DM2. The detection results of the detectors DT10 to DT30 are output to the first control unit CTR1 and the second control unit CTR2. Based on the detection results of the detectors DT10 to DT30, the first control unit CTR1 and the second control unit CTR2 control values such as the current supplied to the LED chips 23A and 23B respectively provided in the first light source unit OPU1 and the second light source unit OPU2. The imaging optical system 83 is a two-sided telecentric optical system that projects the composite image synthesized by the second dichroic mirror DM2 onto the incident end of the fly-eye lens FEL at an equal magnification. In addition, the imaging optical system 83 can also project the composite image synthesized by the second dichroic mirror DM2 onto the incident end of the fly-eye lens FEL at a reduced magnification. The fly-eye lens FEL is formed, for example, by arranging a plurality of lens elements having a positive refractive power vertically and horizontally and densely with their optical axes parallel to the reference optical axis AX. Each lens element constituting the fly-eye lens FEL has a rectangular cross-section similar to the shape of the illumination field to be formed on the reticle MSK (and further the shape of the exposure area to be formed on the plate body P). Therefore, the light beam incident on the fly-eye lens FEL is wavefront-divided by the plurality of lens elements, and a light source image is formed at or near the rear focal plane (exit surface) of each lens element. That is, at or near the rear focal plane (exit surface) of the fly-eye lens FEL, a substantially planar light source, i.e., a secondary light source, composed of a plurality of light source images is formed. The light beam from the secondary light source formed at or near the rear focal plane (exit surface) of the fly-eye lens FEL is incident on the aperture stop 85 disposed nearby. In addition, in this embodiment, the rear focal plane (exit surface) of the fly-eye lens FEL is optically conjugate with the first light source array 20A and the second light source array 20B. The aperture stop 85 is disposed at a position optically substantially conjugate with the entrance pupil plane of the projection optical system PL and has a variable aperture for defining a range contributing to the illumination of the secondary light source. Further, the aperture stop 85 sets the σ value (the ratio of the aperture of the secondary light source image on the pupil plane to the aperture of the pupil plane of the projection optical system) that determines the illumination conditions to a desired value by changing the aperture diameter of the variable aperture. The light from the secondary light source passing through the aperture stop 85 is condensed by the condenser optical system 84 and then illuminates the reticle MSK with a predetermined pattern overlappingly. In addition, the wavelengths of the light emitted from the first light source unit OPU1 and the second light source unit OPU2 are not limited to the above, and the first light source unit OPU1 and the second light source unit OPU2 may be constituted by appropriately combining LED chips that emit light having a peak wavelength in the range of 360 to 440 nm. For example, the peak wavelength of the light emitted from the light emitting portion 231A of the LED chip 23A may also be in the range of 400 to 410 nm. For example, it may also be configured such that the first light source unit OPU1 emits light with a peak wavelength of 405 nm, and the second light source unit OPU2 emits light with a peak wavelength of 365 nm. In addition, it may also be configured such that the first light source unit OPU1 emits light with a peak wavelength of 395 nm, and the second light source unit OPU2 emits light with a peak wavelength of 385 nm. The combination of the wavelengths of the light emitted from the first light source unit OPU1 and the light emitted from the second light source unit OPU2 is not limited to the above examples. In addition, when the combination of the wavelength of the light emitted from the first light source unit OPU1 and the wavelength of the light emitted from the second light source unit OPU2 is a combination other than this embodiment, it is preferable to appropriately change the material of the dichroic mirror according to the wavelength used. As described in detail above, according to this embodiment, the first light source unit OPU1 includes: a plurality of LED chips 23A two-dimensionally arranged on the surface of the substrate 21A, which emit light with a first light emission amount LA1 when a current of a first current value CV1 is supplied within the temperature range of T1 to T2; and a first control unit CTR1 that controls the value of the current supplied to the plurality of LED chips 23A. When the first control unit CTR1 makes the plurality of LED chips 23A emit light with the first light emission amount LA1, the supply of current to the plurality of LED chips 23A starts with a second current value CV2 lower than the first current value CV1, and the current value of the current supplied to the LED chips 23A is increased from the second current value CV2 to the first current value CV1. Thereby, since the current is supplied to the LED chips 23A with a current value corresponding to the temperature rise of the LED chips 23A, the time until the light emitting portion 231A of the LED chips 23A stably emits light with the first light emission amount LA1 can be shortened. In addition, in the present embodiment, when the temperature of the plurality of LED chips 23A is within the range of temperature T3 to temperature T4 and a third current value CV3 lower than the first current value CV1 is supplied, the plurality of LED chips 23A emit light with a second light emission amount LA2 lower than the first light emission amount LA1. When the first control unit CTR1 causes the LED chip 23A supplied with the current having the first current value CV1 and emitting light with the first light emission amount LA1 to enter a state of emitting light with the second light emission amount LA2, the current value of the current supplied to the LED chip 23A is reduced from the first current value CV1 to the third current value CV3. Specifically, the first control unit CTR1 reduces the current value of the current supplied to the LED chip 23A from the first current value CV1 to the third current value CV3 over time. More specifically, the first control unit CTR1 supplies a current value lower than the first current value CV1 and higher than the third current value CV3 to the LED chip 23A, and reduces the current value of the current supplied to the LED chip 23A to the third current value CV3 over time. Thereby, since the current is supplied to the LED chip 23A at a current value corresponding to the decrease in the temperature of the LED chip 23A, the time until the light emitting unit 231A of the LED chip 23A stably emits light with the second light emission amount LA2 can be shortened. (First Modification) The lighting unit to which the first light source unit OPU1 and the second light source unit OPU2 are applied is not limited to the above-described embodiment. FIG. 13 is a schematic diagram showing the configuration of the lighting unit 90A according to the first modification. The lighting unit 90A includes a first light source unit OPU1, a second light source unit OPU2, and a lighting optical system 80A. Since the first light source unit OPU1 and the second light source unit OPU2 are the same as those in the above-described embodiment, detailed description thereof will be omitted. The lighting optical system 80A includes a first condenser optical system 81A1, a second condenser optical system 81B1, a third dichroic mirror DM3, an imaging optical system 83A, a fly-eye lens FEL, an aperture stop 85, and a condenser optical system 84A. The first condenser optical system 81A1 is disposed on or near the above-described predetermined surface PP, and forms a pupil of an enlarged image of the light emitting unit 231A formed by the first magnifying optical system 30A. The first condenser optical system 81A1 may be constituted by a single lens or a lens group including a plurality of lenses. The second condenser optical system 81B1 is disposed on or near the above-described predetermined surface PP, and forms a pupil of an enlarged image of the light emitting unit 231B formed by the second magnifying optical system 30B. The second condenser optical system 81B1 may be constituted by a single lens or a lens group including a plurality of lenses. The third dichroic mirror DM3 transmits at least a part of the light with a peak wavelength of 385 nm and reflects at least a part of the light with a peak wavelength of 365 nm. Thereby, a composite image is formed by overlapping the pupil image formed by the first condenser optical system 81A1 and the pupil image formed by the second condenser optical system 81B1. The imaging optical system 83A is a two-sided telecentric optical system that projects the composite image synthesized by the third dichroic mirror DM3 onto the incident end of the compound eye lens FEL at an equal magnification. In addition, the imaging optical system 83A can also project the composite image synthesized by the third dichroic mirror DM3 onto the incident end of the compound eye lens FEL at a reduced magnification. The light beam incident on the compound eye lens FEL is wavefront-divided by a plurality of lens elements 60, and a light source image is formed respectively at the rear focal plane or near it of each lens element 60. The light beam from the secondary light source formed at the rear focal plane or near it of the compound eye lens FEL is incident on the aperture stop 85 arranged near it. The light from the secondary light source passing through the aperture stop 85, after being condensed by the condenser optical system 84A, illuminates the mask MSK with a predetermined pattern superimposed. The projection optical system PL of the first modification is an Offner type optical system supported by the optical table 73 below the mask stage MST (-Z side). The projection optical system PL forms, for example, an arc-shaped image field with the Y-axis direction as the length direction. When the illumination area on the mask MSK is illuminated by the illumination light IL from the illumination system IOP, the projection image (partially erect image) of the circuit pattern of the mask MSK in the illumination area is formed on the irradiation area (exposure area (conjugate to the illumination area)) of the plate body P arranged on the image plane side of the projection optical system PL through the projection optical system PL by the illumination light IL passing through the mask MSK. Thereby, the plate body P is exposed and the pattern of the mask MSK is transferred onto the plate body P. As shown in the second modification, the first light source unit OPU1 and the second light source unit OPU2 can also be applied to the light source of the exposure apparatus equipped with the Offner type projection optical system PL. (Second modification) As the luminous fluxes of the light-emitting portions 231A of the LED chips 23A and 231B of the LED chips 23B described above, they decrease when the temperatures of the LED chips 23A and 23B rise. In other words, the luminous efficiencies of the LED chips 23A and 23B decrease when the temperature rises. Therefore, it is preferable to respectively mount the first light source array 20A and the second light source array 20B on the heat dissipation portions to cool the LED chips 23A and 23B. FIG. 14(A) is a top view showing an example of the heat dissipation part 40 in the second modification, and FIG. 14(B) is a top view showing a state in which the first light source array 20A is mounted on the heat dissipation part 40. In FIGS. 14(A) and 14(B), the length direction of the heat dissipation part 40 is the X2 direction, the short side direction is the Y2 direction, and the thickness direction is the Z2 direction. The X2 direction, the Y2 direction, and the Z2 direction are orthogonal to each other. As shown in FIG. 14(A), the heat dissipation part 40 has a plurality of flow paths 403 that extend in the Y2 direction and in which refrigerant flows internally from a refrigerant inlet 401 provided at one end side in the Y2 direction of the heat dissipation part 40 toward a refrigerant outlet 402 provided at the other end side in the Y2 direction. In the second modification, among the LED chips 23A mounted on the substrate 21A of the heat dissipation part 40, the LED chips 23A adjacent to each other in the X2 direction are connected in series. Here, the set of the LED chips 23A connected in series is sequentially referred to as the first group G1, the second group G2, the third group G3, the fourth group G4, and the fifth group G5 from the refrigerant inlet 401 toward the refrigerant outlet 402 (see FIG. 14(B)). Therefore, in FIG. 14(B), for example, in the direction indicated by the arrow AR1 (+X2 direction), current flows to the LED chip 23A. On the other hand, the refrigerant in the heat dissipation part 40 flows in the direction indicated by the arrow AR2 (−Y2 direction). Since the cooling effect brought by the refrigerant is higher the closer to the refrigerant inlet 401, in the case where the same current value is supplied to all the LED chips 23A included in the first light source array 20A, the temperature of the LED chips 23A becomes higher from the refrigerant inlet 401 toward the refrigerant outlet 402. That is, the closer the LED chip 23A is to the refrigerant inlet 401, the lower its temperature. In the LED chips 23A connected in series, the current value of the current supplied to each LED chip 23A cannot be made different for each LED chip 23A. Therefore, the current value of the current supplied to the LED chips 23A connected in series is controlled to be the same in the wiring direction (X2 direction). Here, if there is a temperature difference between the LED chips 23A adjacent to each other in the wiring direction (X2 direction), it is difficult to correct the light emission amount of the light emitting part 231A of the LED chip 23A. Therefore, in the second modification, the substrate 21A is mounted on the heat dissipation part 40 such that the wiring direction of the LED chips 23A (refer to the arrow AR1) is orthogonal to the direction in which the refrigerant flows in the heat dissipation part 40 (refer to the arrow AR2). Configured in the manner shown in FIG. 14(B), for each LED chip 23A along the wiring direction (LED chips 23A included in the same group), the distance from each of them to the refrigerant inlet 401 is approximately equal, so their temperatures change in the same way. Therefore, by controlling the current value of the current supplied to each wiring (each group), the luminous fluxes of the light-emitting portions 231A of the respective LED chips 23A can be made uniform. Specifically, the current value of the current supplied to the LED chips 23A in the first group G1 close to the refrigerant inlet 401 is made the lowest, and for groups farther from the refrigerant inlet 401, the current value of the supplied current is made higher. Thereby, the luminous fluxes of the light-emitting portions 231A of the plurality of LED chips 23A included in the first light source array 20A can be made substantially the same, and the illuminance uniformity can be improved. The same applies to the LED chips 23B. Additionally, the LED chips 23A and the LED chips 23B can also be directly mounted on the heat dissipation portion 40. In the above-described embodiments and variations, the lighting units 90 and 90A include the first light source unit OPU1, the second light source unit OPU2, and the lighting optical systems 80 and 80A including the second dichroic mirror DM2, but are not limited thereto. For example, the lighting units 90 and 90A may have only either the first light source unit OPU1 or the second light source unit OPU2. In this case, the lighting optical systems 80 and 80A may have any configuration as long as they can guide the light emitted from the first light source unit OPU1 or the second light source unit OPU2 to the reticle MSK. In the above-described embodiments and their variations, it has been described that the exposure device is used in the manufacture of a liquid crystal display device (flat panel display), but the exposure device may also be one that exposes a silicon wafer to manufacture a semiconductor. The above-described embodiments are preferred examples of the present invention. However, it is not limited thereto, and various modifications can be made without departing from the gist of the present invention. 10: Exposure device 20A: First light source array 20B: Second light source array 21A, 21B: Substrate 23A, 23B: LED chip 231A: Light emitting part 231B: Light emitting part 30A: First magnifying optical system 30B: Second magnifying optical system 31A: Lens part 31B: Lens part 40: Heat dissipation part 401: Refrigerant inlet 402: Refrigerant outlet 403: Flow path 60: Lens element 70: Body 71: Base (vibration isolation table) 72A: Support column 72B: Support column 73: Optical platform 74: Support body 75: Sliding guide 80, 80A: Illumination optical system 81A: First condenser optical system 81A1: First condenser optical system 81B: Second condenser optical system 81B1: Second condenser optical system 83: Imaging optical system 83A: Imaging optical system 84: Condenser optical system 84A: Condenser optical system 85: Aperture stop 90, 90A: Illumination unit 100: Projection optical unit AR1: Arrow AR2: Arrow AX: Reference optical axis a1: Length of one side of the light emitting surface a2: Length of one side of the light emitting surface CTR1: First control unit CTR2: Second control unit CV1: First current value CV2: Second current value CV3: Third current value DM1: First dichroic mirror DM2: Second dichroic mirror DM3: Third dichroic mirror DT10: Detector DT20: Detector DT30: Detector F: Ground FEL: Compound eye lens G1: First group G2: Second group G3: Third group G4: Fourth group G5: Fifth group IL: Illumination light IOP: Illumination system LA1: First luminous flux LA2: Second luminous flux MSK: Reticle MST: Reticle stage OA: Optical axis OPU1: First light source unit OPU2: Second light source unit PL: Projection optical system P: Glass substrate PP: Predetermined surface PST: Substrate stage P1: Pitch P2: Pitch T1: Temperature T2: Temperature T3: Temperature T4: Temperature [Fig. 1] Fig. 1 is a schematic diagram showing the configuration of an exposure apparatus according to an embodiment. [Fig. 2] Fig. 2 is a schematic diagram showing the configuration of the illumination unit according to the present embodiment. [Fig. 3] Fig. 3(A) is a top view schematically showing the configuration of the first and second light source arrays, and Fig. 3(B) is a diagram schematically showing the internal configuration of the first and second light source units. [Fig. 4] Fig. 4 is a diagram illustrating the relationship between the temperature and the light emission amount of an LED chip. [Fig. 5] Fig. 5(A) is a chart showing the measurement results of the light emission amount of the light emitting portion of the LED chip in Comparative Example 1, and Fig. 5(B) is a chart obtained by magnifying the range of the light emission amount deviation rate of 0% to 2% in Fig. 5(A). [Fig. 6] Fig. 6 is a diagram showing the output with respect to the elapsed time in Comparative Example 1. [Fig. 7] Fig. 7(A) is a chart showing the measurement results of the light emission amount of the light emitting portion of the LED chip in the present embodiment, and Fig. 7(B) is a chart obtained by magnifying the range of the light emission amount deviation rate of 0% to 2% in Fig. 7(A). [Fig. 8] Fig. 8(A) is a diagram showing the output of the first control unit with respect to the elapsed time in the present embodiment, and Fig. 8(B) is a chart obtained by magnifying the range of the output of 98% to 100% in Fig. 8(A). [Fig. 9] Fig. 9(A) is a chart showing the simulation results of the light emission amount of the light emitting portion of the LED chip in Comparative Example 2, and Fig. 9(B) is a diagram obtained by magnifying the range of the light emission amount deviation rate of -2% to 0% and the elapsed time of 0 seconds to 50 seconds in Fig. 9(A). [Fig. 10] Fig. 10 is a diagram showing the output with respect to the elapsed time in Comparative Example 2. [Fig. 11] Fig. 11(A) is a chart showing the simulation results of the light emission amount of the light emitting portion of the LED chip in the present embodiment, and Fig. 11(B) is a diagram obtained by magnifying the range of the light emission amount deviation rate of -2% to 0% and the elapsed time of 0 seconds to 50 seconds. [Fig. 12] Fig. 12 is a diagram showing the output of the first control unit with respect to the elapsed time in the present embodiment. [Fig. 13] Fig. 13 is a schematic diagram showing the configuration of the illumination unit according to Modification 1. [Fig. 14] Fig. 14(A) is a top view showing an example of the heat dissipation portion in Modification 2, and Fig. 14(B) is a top view showing a state in which the first light source array is mounted on the heat dissipation portion.

Claims

1. A driving method for a light source element, wherein if a first current value is supplied when the temperature of the light source element is within a first temperature range, the light source element emits light with a first luminous intensity. The driving method for the aforementioned light source element includes: when the aforementioned light source element is in a state of emitting light with the aforementioned first luminous intensity, supplying current to the aforementioned light source element with a second current value lower than the aforementioned first current value; and increasing the current value supplied to the aforementioned light source element from the aforementioned second current value to the aforementioned first current value; wherein the aforementioned second current value is a predetermined current value, and in the aforementioned increasing step, the current value supplied to the aforementioned light source element is increased from the aforementioned second current value to the aforementioned first current value by a predetermined first proportion; wherein the aforementioned second current value and the aforementioned first proportion are determined based on the change in the luminous intensity offset rate of the aforementioned light source element when the current is supplied to the aforementioned light source element with the aforementioned first current value.

2. The driving method for the light source element as described in claim 1, wherein, In the aforementioned additional step, the current value supplied to the aforementioned light source element is increased from the aforementioned second current value to the aforementioned first current value over time.

3. The driving method for the light source element as described in claim 1, wherein, The aforementioned first ratio is a fixed ratio.

4. The driving method for the light source element as described in claim 1 or 2, wherein, Before the current value supplied to the aforementioned light source element changes from the aforementioned second current value to the aforementioned first current value, the aforementioned light source element emits light with the aforementioned first luminous intensity.

5. The driving method for the light source element as described in claim 4, wherein, After the current value supplied to the aforementioned light source element becomes the aforementioned first current value, the aforementioned light source element continues to emit light with the aforementioned first luminous intensity.

6. A driving method for the light source element as described in claim 1 or 2, wherein, The aforementioned first temperature range is 20℃~90℃.

7. A driving method for a light source element, wherein if a first current value is supplied to the light source element when its temperature is within a first temperature range, the light source element emits light with a first luminous intensity. The driving method comprises: when the light source element is in a state emitting light with the first luminous intensity, supplying current to the light source element with a second current value lower than the first current value; and increasing the current value supplied to the light source element from the second current value to the first current value; wherein the second current value is a predetermined current value, and in the increasing step, the current value supplied to the light source element is increased from the second current value to the first current value by a predetermined first proportion; wherein the second current value is determined based on the change in the luminous intensity shift rate of the light source element when current is initially supplied to the light source element with a fifth current value lower than the first current value and the current value supplied to the light source element is increased by a third proportion to the first current value, and is the current value at which current is initially supplied to the light source element. The aforementioned first ratio is determined based on the change in the light emission offset rate of the aforementioned light source element when the current supply to the aforementioned light source element starts from the aforementioned fifth current value and the current value supplied to the aforementioned light source element increases from the aforementioned third ratio to the aforementioned first current value. The aforementioned fifth current value and the aforementioned third ratio are determined based on the change in the light emission offset rate of the aforementioned light source element when the current supply to the aforementioned light source element starts from the aforementioned first current value.

8. A driving method for a light source element, wherein when the temperature of the light source element is within a first temperature range, it emits light with a first luminous intensity when a first current value is supplied, and when the temperature of the light source element is within a second temperature range, it emits light with a second luminous intensity lower than the first luminous intensity when a third current value lower than the first current value is supplied. The driving method for the aforementioned light source element includes: when the aforementioned light source element, which emits light with the first luminous intensity when supplied with the first current value, is in a state of emitting light with the second luminous intensity, supplying current to the aforementioned light source element with a fourth current value higher than the third current value; and reducing the current value supplied to the aforementioned light source element from the fourth current value to the third current value; wherein the fourth current value is a predetermined current value, and in the aforementioned reduction step, the current value supplied to the aforementioned light source element is reduced from the fourth current value to the third current value by a predetermined second proportion; The aforementioned fourth current value and the aforementioned second ratio are determined based on the change in the light emission offset rate of the aforementioned light source element when the current value supplied to the aforementioned light source element that emits light with the aforementioned first light emission amount changes from the aforementioned first current value to the aforementioned third current value.

9. The driving method for the light source element as described in claim 8, wherein, In the aforementioned reduction step, the current value supplied to the aforementioned light source element is reduced from the aforementioned fourth current value to the aforementioned third current value over time.

10. A method for driving a light source element as described in claim 8, wherein, The aforementioned second ratio is a fixed ratio.

11. A driving method for a light source element, wherein when the temperature of the light source element is within a first temperature range, it emits light with a first luminous intensity when a first current value is supplied, and when the temperature of the light source element is within a second temperature range, it emits light with a second luminous intensity lower than the first luminous intensity when a third current value lower than the first current value is supplied. The driving method for the aforementioned light source element comprises: when the aforementioned light source element, which emits light with the first luminous intensity when supplied with the first current value, is in a state of emitting light with the second luminous intensity, supplying current to the aforementioned light source element with a fourth current value higher than the third current value; and reducing the current value supplied to the aforementioned light source element from the fourth current value to the third current value; wherein the fourth current value is a predetermined current value, and in the aforementioned reduction step, the current value supplied to the aforementioned light source element is reduced from the fourth current value to the third current value by a predetermined second proportion; The aforementioned fourth current value is determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current supply to the aforementioned light source element starts at a sixth current value higher than the aforementioned third current value, and the current value supplied to the aforementioned light source element decreases by a fourth ratio to the aforementioned third current value. The aforementioned second ratio is determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current supply to the aforementioned light source element starts at the aforementioned sixth current value, and the current value supplied to the aforementioned light source element decreases by the aforementioned fourth ratio to the aforementioned third current value. The aforementioned sixth current value and the aforementioned fourth ratio are determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current value supplied to the aforementioned light source element is changed from the aforementioned first current value to the aforementioned third current value.

12. A driving method for a light source element as described in any of claims 1, 2, 7, 8, 9, and 11, wherein, The aforementioned light source element is an LED element.

13. A driving method for a light source element as described in any of claims 1, 2, 7, 8, 9, and 11, wherein, The peak wavelength of the light emitted from the aforementioned light source element is in the range of 360–370 nm.

14. A driving method for a light source element as described in any of claims 1, 2, 7, 8, 9, and 11, wherein, The peak wavelength of the light emitted from the aforementioned light source element is in the range of 380–390 nm.

15. A driving method for a light source element as described in any of claims 1, 2, 7, 8, 9, and 11, wherein, The peak wavelength of the light emitted from the aforementioned light source element is in the range of 400–410 nm.

16. A light source unit comprising: a plurality of light source elements arranged in two dimensions on the surface of a fixed object, each emitting light with a first luminous intensity when supplied with a first current value at a temperature within a first temperature range; and a control unit controlling the value of the current supplied to the plurality of light source elements; wherein, when the plurality of light source elements are in a state of emitting light with the first luminous intensity, the control unit supplies current to the plurality of light source elements starting with a second current value lower than the first current value, thereby increasing the current value supplied to the plurality of light source elements from the second current value to the first current value; wherein the second current value is a predetermined current value; and the control unit increases the current value supplied to the plurality of light source elements from the second current value to the first current value by a predetermined first proportion; wherein the second current value and the first proportion are determined based on the change in the luminous intensity offset rate of the plurality of light source elements when current is supplied to the plurality of light source elements starting with the first current value.

17. The light source unit as described in claim 16, wherein, The aforementioned control unit causes the current value supplied to the aforementioned plurality of light source elements to increase from the aforementioned second current value to the aforementioned first current value over time.

18. The light source unit as described in claim 16, wherein, The aforementioned first ratio is a fixed ratio.

19. The light source unit as described in claim 16 or 17, wherein, Before the current value supplied to the aforementioned plurality of light source elements changes from the aforementioned second current value to the aforementioned first current value, the aforementioned plurality of light source elements emit light with the aforementioned first luminous intensity.

20. The light source unit as described in claim 19, wherein, After the current value supplied to the aforementioned plurality of light source elements becomes the aforementioned first current value, the aforementioned plurality of light source elements continue to emit light with the aforementioned first luminous intensity.

21. The light source unit as described in claim 16 or 17, wherein, The aforementioned first temperature range is 20℃~90℃.

22. A light source unit comprising: a plurality of light source elements arranged in two dimensions on the surface of a fixed object, each emitting light with a first luminous intensity when supplied with a first current value at a temperature within a first temperature range; and a control unit controlling the value of the current supplied to the plurality of light source elements; wherein, when the plurality of light source elements are in a state of emitting light with the first luminous intensity, the control unit supplies current to the plurality of light source elements starting with a second current value lower than the first current value, thereby increasing the current value supplied to the plurality of light source elements from the second current value to the first current value; wherein the second current value is a predetermined current value, and the control unit increases the current value supplied to the plurality of light source elements from the second current value to the first current value by a predetermined first proportion; The aforementioned second current value is determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current supply to the aforementioned light source element starts at a fifth current value lower than the aforementioned first current value, and the current value supplied to the aforementioned light source element increases by a third ratio to the aforementioned first current value. The aforementioned first ratio is determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current supply to the aforementioned light source element starts at the aforementioned fifth current value, and the current value supplied to the aforementioned light source element increases by the aforementioned third ratio to the aforementioned first current value. The aforementioned fifth current value and the aforementioned third ratio are determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current supply to the aforementioned light source element starts at the aforementioned first current value.

23. A light source unit comprising: a plurality of light source elements arranged in two dimensions on the surface of a fixed object, wherein each element emits light with a first luminous intensity when supplied with a first current value at a temperature within a first temperature range, and emits light with a second luminous intensity when supplied with a third current value lower than the first current value at a temperature within a second temperature range; and a control unit controlling the value of the current supplied to the plurality of light source elements; wherein the control unit, when the plurality of light source elements emitting light with the first luminous intensity when supplied with the first current value are in a state of emitting light with the second luminous intensity, supplies current to the plurality of light source elements with a fourth current value higher than the third current value, thereby reducing the current value supplied to the plurality of light source elements from the fourth current value to the third current value; wherein the fourth current value is a predetermined current value; and the control unit reduces the current value supplied to the plurality of light source elements from the fourth current value to the third current value by a predetermined second proportion; The aforementioned fourth current value and the aforementioned second ratio are determined based on the change in the emission offset rate of the aforementioned plurality of light source elements when the current value supplied to the aforementioned plurality of light source elements that emits light with the aforementioned first emission amount changes from the aforementioned first current value to the aforementioned third current value.

24. The light source unit as described in claim 23, wherein, The aforementioned control unit causes the current value supplied to the aforementioned plurality of light source elements to decrease from the aforementioned fourth current value to the aforementioned third current value over time.

25. The light source unit as described in claim 23, wherein, The aforementioned second ratio is a fixed ratio.

26. A light source unit comprising: a plurality of light source elements arranged in two dimensions on the surface of a fixed object, each emitting light with a first luminous intensity when supplied with a first current value at a temperature within a first temperature range, and emitting light with a second luminous intensity when supplied with a third current value lower than the first current value at a temperature within a second temperature range; and a control unit controlling the value of the current supplied to the plurality of light source elements; wherein the control unit, when the plurality of light source elements emitting light with the first luminous intensity at a current of the first current value are in a state of emitting light with the second luminous intensity, supplies current to the plurality of light source elements with a fourth current value higher than the third current value, thereby reducing the current value supplied to the plurality of light source elements from the fourth current value to the third current value; wherein the fourth current value is a predetermined current value; and the control unit reduces the current value supplied to the plurality of light source elements from the fourth current value to the third current value by a predetermined second proportion; The aforementioned fourth current value is determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current supply to the aforementioned light source element starts at a sixth current value higher than the aforementioned third current value, and the current value supplied to the aforementioned light source element decreases by a fourth ratio to the aforementioned third current value. The aforementioned second ratio is determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current supply to the aforementioned light source element starts at the aforementioned sixth current value, and the current value supplied to the aforementioned light source element decreases by the aforementioned fourth ratio to the aforementioned third current value. The aforementioned sixth current value and the aforementioned fourth ratio are determined based on the change in the luminous intensity shift rate of the aforementioned light source element when the current value supplied to the aforementioned light source element is changed from the aforementioned first current value to the aforementioned third current value.

27. The light source unit described in any of the following requests: 16, 17, 22, 23, 24, and 26, wherein... The aforementioned plurality of light source elements includes: a plurality of first light source elements arranged in a first direction and connected in series; and a plurality of second light source elements separated from the aforementioned plurality of first light source elements in a second direction orthogonal to the aforementioned first direction, arranged in the aforementioned first direction and connected in series; the aforementioned fixed object is a substrate mounted on a heat dissipation section; the aforementioned heat dissipation section has: a plurality of flow paths extending in the aforementioned second direction and internally flowing refrigerant from a refrigerant inlet disposed at one end of the aforementioned second direction to a refrigerant outlet disposed at the other end of the aforementioned second direction.

28. The light source unit described in any of the following requests: 16, 17, 22, 23, 24, and 26, wherein... The aforementioned plurality of light source elements includes: a plurality of first light source elements arranged in a first direction and connected in series; a plurality of second light source elements separated from the aforementioned plurality of first light source elements in a second direction orthogonal to the aforementioned first direction, arranged in the aforementioned first direction and connected in series; the aforementioned fixed object is a heat dissipation part; the aforementioned heat dissipation part has: a plurality of flow paths extending in the aforementioned second direction and internally flowing refrigerant from a refrigerant inlet provided at one end of the aforementioned second direction to a refrigerant outlet provided at the other end of the aforementioned second direction.

29. The light source unit described in any of the following requests: 16, 17, 22, 23, 24, 26, wherein... The aforementioned multiple light source elements are multiple LED elements.

30. The light source unit described in any of the following requests: 16, 17, 22, 23, 24, 26, wherein... The peak wavelength of the light emitted from the aforementioned plurality of light source elements is in the range of 360–370 nm.

31. The light source unit described in any of the following requests: 16, 17, 22, 23, 24, 26, wherein... The peak wavelength of the light emitted from the aforementioned plurality of light source elements is in the range of 380 to 390 nm.

32. The light source unit described in any of the following requests: 16, 17, 22, 23, 24, 26, wherein... The peak wavelength of the light emitted from the aforementioned plurality of light source elements is in the range of 400 to 410 nm.

33. The light source unit described in any of the following requests: 16, 17, 22, 23, 24, and 26, wherein... The aforementioned light source unit is used in the exposure device.

34. An illumination unit comprising: a light source unit as described in any one of claims 16 to 33; and an illumination optical system for guiding light emitted from the aforementioned light source unit to an irradiated object.

35. An illumination unit comprising: a plurality of light source units as described in any one of claims 16 to 33; and an illumination optical system comprising a synthesizing optical element for synthesizing light emitted from the plurality of the aforementioned light source units, and guiding the synthesized light emitted from the aforementioned synthesizing optical element to an irradiated object.

36. An exposure apparatus comprising: an illumination unit as described in claim 34 or 35; and a projection optical system for projecting a pattern image of a photomask illuminated by the aforementioned illumination unit onto a photosensitive substrate.

37. The exposure apparatus as described in claim 36, wherein, The aforementioned photosensitive substrate has at least one side with a length or diagonal length of 500 mm or more.

38. An exposure method using an exposure apparatus as described in claims 36 or 37, comprising: illuminating a photomask by means of the aforementioned illumination unit; and projecting a pattern image of the photomask onto a photosensitive substrate using the aforementioned projection optics system.

39. A method for driving a light source element, comprising: when the light source element is in a state of emitting light at the first luminous intensity, supplying current to the light source element at a second current value lower than the first current value; and increasing the current value of the current supplied to the light source element from the second current value to the first current value; wherein the second current value is a predetermined current value, and in the increasing step, the current value of the current supplied to the light source element is increased from the second current value to the first current value by a predetermined first ratio; wherein the second current value and the first ratio are determined based on the change in the luminous intensity offset rate of the light source element when the current is initially supplied to the light source element at the first current value.

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