JP2011209394A - Projector and focus adjustment method - Google Patents

Abstract

Provided are a projector and a focus adjustment method capable of suppressing a change in a focus position of a projection optical apparatus.
The projector includes a projection optical device that projects an image. The projection optical device 4 includes a first lens group 411 whose focal position changes to a position far from the projection optical device 4 and a second lens group 412 that changes to a close position in response to a temperature rise. The projector includes a heating unit 5 that heats at least one of the first lens group 411 and the second lens group 412, and a control unit that controls the heating unit 5. The heating unit 5 is controlled by the control unit so as to eliminate the fluctuation of the focal position of the projection optical apparatus 4 due to the temperature rise.
[Selection] Figure 2

Description

  The present invention relates to a projector and a focus adjustment method.

Conventionally, a light source device, a light modulation device that modulates a light beam emitted from the light source device to form image light according to image information, and a projection that enlarges and projects the image light onto a projection surface such as a screen A projector including an optical device is known. As such a projection optical apparatus, a combined lens in which a plurality of lenses such as a zoom lens and a focus lens are provided in a lens barrel is often employed.
By the way, when an image corresponding to the image light projected from the projection optical device is clearly displayed on the projection surface when the projector is used, it is necessary to adjust the focal position of the projection optical device. On the other hand, a projector that automatically adjusts the focal position of a projection optical device is known (see, for example, Patent Document 1).
In the projector (projection display device) described in Patent Document 1, the distance between the projection optical device (projection lens) and the screen is measured with an invisible light beam, and the focus of the projection optical device is automatically adjusted to the optimum focus position. By doing so, operability and accuracy of focus adjustment are achieved.

JP-A-3-149538

However, in the projector described in Patent Document 1, since the focal position of the projection optical apparatus is adjusted based on the distance between the projector and the screen, the deviation of the focal position of the projection optical apparatus caused by temperature cannot be corrected. There is.
More specifically, when the projector is used, the image light is transmitted through the plurality of lenses of the projection optical apparatus, so that the temperature of each lens rises. Here, some of the plurality of lenses have lens characteristics (curvature, refractive index, etc.) that change according to temperature, and the distance between the lenses may change due to temperature changes of the lens barrel. In such a case, the focal position of the entire projection optical apparatus changes between a low temperature (for example, at the start of use) and a high temperature (for example, after a predetermined time has elapsed since the start of use). For this reason, there is a problem that the focal position of the projection optical apparatus set based on the above-mentioned distance changes between a low temperature and a high temperature, and the projected image cannot be displayed clearly. Therefore, there has been a demand for a configuration that can suppress fluctuations in the focal position of the projection optical apparatus.

  The objective of this invention is providing the projector and focus adjustment method which can suppress the fluctuation | variation of the focus position of a projection optical apparatus.

  The projector of the present invention is a projector including a projection optical device that projects an image, and the projection optical device includes a first lens group in which a focal position fluctuates to a position far from the projection optical device according to a temperature rise, and The projector includes a second lens group that fluctuates in a close position, and the projector includes a heating unit that heats at least one of the first lens group and the second lens group, and a control unit that controls the heating unit. And the control means controls the heating means so as to eliminate fluctuations in the focal position of the projection optical apparatus accompanying a temperature rise.

  According to the present invention, when the focus position of the projection optical apparatus fluctuates due to a rise in the temperature of the projection optical apparatus, the first change is made so as to eliminate the fluctuation of the focus position of the projection optical apparatus accompanying the temperature rise. Since at least one of the lens group and the second lens group is heated, the variation in the focal position becomes small. Accordingly, a change in the focal position of the projection optical apparatus can be suppressed, so that a clear image display state can be maintained.

Here, in order to adjust the temperature of the lens group, a configuration in which cooling means for cooling the lens group is provided is conceivable. An example of such cooling means is a fan that blows cooling air. However, in the case where such a fan is provided, there is a problem in that the noise of the projector is hindered because wind noise is generated due to the blowing of cooling air.
On the other hand, for example, by employing a heater as the heating means, it is possible to suppress the generation of noise such as wind noise, and the projector can be made quieter than when the cooling means is employed.

In the projector according to the aspect of the invention, the control unit may obtain information relating to fluctuations in the first lens group and the second lens group, respectively, relating to fluctuations in the focal position of the projection optical apparatus as the temperature rises. , Calculating a difference between the fluctuation-related information acquired by the information acquisition unit at a predetermined timing and the fluctuation-related information acquired by the information acquisition unit after the predetermined timing, and controlling the heating unit according to the difference It is preferable to have a heating control unit.
Here, the variation-related information includes information based on the temperature of the lens group (including the vicinity temperature) detected by the temperature sensor.

According to the present invention, the difference between the fluctuation related information acquired at a predetermined timing and the fluctuation related information acquired after the predetermined timing is calculated, and the heating unit is controlled according to the difference. As a result, the variation amount of the focal position after the predetermined timing with respect to the focal position at the predetermined timing can be determined by the difference, and the lens group can be heated according to the variation amount.
For example, when the heating means is a heater, by appropriately setting the applied voltage to the heater, the heater set temperature, the heater heating time, etc. corresponding to the focal position fluctuation amount, the lens group corresponding to the fluctuation amount Heating can be performed appropriately.

The focus adjustment method of the present invention is a focus adjustment method for a projection optical device, the first lens group of the projection optical device having a focal position that fluctuates to a position far from the projection optical device according to a temperature rise, and In the second lens group that fluctuates to a close position, an information acquisition procedure for respectively acquiring fluctuation-related information regarding fluctuations in the focal position of the projection optical apparatus accompanying a temperature rise, And a heating control procedure for controlling a heating means for heating at least one of the first lens group and the second lens group so as to eliminate the variation of the focal position of the projection optical apparatus. .
According to the present invention, when the focus position of the projection optical apparatus fluctuates due to an increase in the temperature of the projection optical apparatus, the first lens is arranged so as to eliminate the fluctuation of the focus position of the projection optical apparatus accompanying the temperature increase. Since at least one of the group and the second lens group is heated, the same effect as that of the projector described above is obtained.

FIG. 1 is a schematic diagram illustrating a configuration of a projector according to a first embodiment of the invention. The schematic diagram which shows the structure of the projection optical apparatus in the said embodiment, a heating unit, and a temperature sensor. The figure which shows the structure of the control unit in the said embodiment. The flowchart which shows the temperature control process performed by the control unit in the said embodiment. The figure which shows an example of the table memorize | stored in the memory | storage part in the said embodiment.

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
[Configuration of projector]
FIG. 1 is a schematic diagram illustrating a configuration of a projector 1 according to the present embodiment.
The projector 1 according to the present embodiment modulates a light beam emitted from a light source device 311 provided therein to form an image according to image information, and the image is projected onto a projection surface W (FIG. 2). (Refer to) Enlarged projection. As shown in FIG. 1, the projector 1 includes an exterior housing 2, an image forming device 3, a projection optical device 4, a heating unit 5, a control unit 6, and a temperature sensor 7.
Among these, the exterior housing 2 is a housing formed entirely in a substantially rectangular parallelepiped shape with synthetic resin or metal, and accommodates and arranges the above-described devices 3 and 4 and the units 5 and 6 inside.

[Configuration of image forming apparatus]
The image forming apparatus 3 is an optical apparatus that forms image light according to image information under the control of the control unit 6. The image forming apparatus 3 accommodates and arranges the illumination optical device 31, the color separation optical device 32, the relay optical device 33, and the electro-optical device 34 at predetermined positions on the illumination optical axis A set therein. And an optical component casing 35 that supports a projection optical device 4 to be described later.

The illumination optical device 31 includes a light source device 311, a pair of lens arrays 312 and 313, a polarization conversion element 314, and a superimposing lens 315.
The color separation optical device 32 includes dichroic mirrors 321 and 322 and a reflection mirror 323, and the relay optical device 33 includes an incident side lens 331, a relay lens 333, and reflection mirrors 332 and 334.
The electro-optical device 34 includes a field lens 341, three liquid crystal panels 342 as light modulators (the liquid crystal panels for red light, green light, and blue light are respectively 342R, 342G, and 342B), and Three incident-side polarizing plates 343, a viewing angle compensation plate 344, an outgoing-side polarizing plate 345, and a cross dichroic prism 346 as a color synthesizing optical device are provided.

  In such an image forming apparatus 3, the illumination optical device 31 emits a light beam whose illuminance in the illumination area is substantially uniform. , Blue (B). Each separated color light is modulated by each liquid crystal panel 342 according to image information, and an image for each color light is formed. Then, the image for each color light is synthesized by the cross dichroic prism 346 and enlarged and projected on the projection surface W (see FIG. 2) by the projection optical device 4.

[Configuration of projection optical device]
FIG. 2 is a schematic diagram illustrating the configuration of the projection optical device 4, the heating unit 5, and the temperature sensor 7.
The projection optical device 4 forms an image formed by the image forming device 3 on the projection surface W and enlarges and projects the image. As shown in FIG. 2, the projection optical device 4 includes three lens groups 41 (first lens group 411, second lens group 412, and third lens group 413 from the side close to the projection surface W). And a lens barrel 42 that houses each lens group 41 therein. The “lens group” refers to a group of one or more lenses having a predetermined function.

  In the first lens group 411, as the temperature of the first lens group 411 increases, the focal position of the projection optical apparatus 4 moves away from the projection optical apparatus 4 along the illumination optical axis A (“+” in FIG. 2). ”Direction). On the other hand, the second lens group 412 has a characteristic that the focal position fluctuates in the direction approaching the projection optical device 4 (the “−” direction in FIG. 2) as the temperature of the second lens group 412 increases. The third lens group 413 has a characteristic that the focal position does not change even if a temperature change occurs in the third lens group 413.

Here, the focal position of the projection optical apparatus 4 varies depending on the lens characteristics of the lens group 41 and the inter-lens distance that change according to the temperature.
More specifically, as shown in FIG. 2, when the temperature change occurs in the projection optical device 4, the focus position of the projection optical device 4 is changed from the focus position P before the temperature change to the illumination optical axis A as shown by the broken line. Along the direction of the projection optical apparatus 4 (position indicated by the position P1) or the direction of moving away (position indicated by the position P2). In such a case, a so-called focus shift occurs in the projected image.
Therefore, in the present embodiment, the fluctuation of the focal position of the projection optical device 4 due to this temperature change is suppressed by the following configuration.

[Configuration of heating unit]
The heating unit 5 corresponds to the heating means of the present invention and is for heating the lens group 41. The heating unit 5 includes a heater 51 that heats the first lens group 411 and a heater 52 that heats the second lens group 412. The configurations of the heaters 51 and 52 are not particularly limited as long as they can heat the corresponding lens groups 411 and 412 and heat the entire lenses of the lens groups 411 and 412 to a uniform temperature. Specifically, the heaters 51 and 52 can be configured by covering the peripheral portions of the lens groups 411 and 412 with heating wires.

[Configuration of temperature sensor]
The temperature sensor 7 is a detection unit that detects the temperature of the lens group 41 under the control of the control unit 6 described later. Specifically, the temperature sensor 7 detects the temperature near the lens group 41. The temperature sensor 7 includes a first sensor 71 and a second sensor 72 that detect temperatures near the first lens group 411 and the second lens group 412, respectively.

[Configuration of control unit]
FIG. 3 is a diagram showing the configuration of the control unit 6.
The control unit 6 corresponds to the control means of the present invention, and controls the operation of the entire projector 1 autonomously or according to the operation of the user. For example, the control unit 6 controls the heating state by the heaters 51 and 52 described above. For this reason, the control unit 6 has the information acquisition part 61, the difference calculation part 62, the difference determination part 63, the heating control part 64, and the memory | storage part 65, as shown in FIG.
And the control unit 6 performs the following temperature control processing by these each part. It is assumed that various programs and data necessary for control by the control unit 6 are stored in the storage unit 65.

[Temperature control processing]
FIG. 4 is a flowchart showing the temperature control process executed by the control unit 6.
When the power of the projector 1 is turned on and the light beam is emitted from the light source device 311, the control unit 6 described above executes a temperature control process described below to suppress the variation in the focal position of the projection optical device 4. . Specifically, this temperature control process is performed in accordance with a temperature control program stored in the storage unit 65.

In this temperature control process, as shown in FIG. 4, first, the information acquisition unit 61 acquires the initial temperature t0 detected by the temperature sensor 7 as initial information at a predetermined timing (step S1). Specifically, in the present embodiment, this predetermined timing is when the user adjusts the focal position of the projection optical device 4. When the initial temperature t0 is acquired, the difference (initial difference Δt0) is set to “0” and stored in the storage unit 65 as the previous difference.
Thereafter, the information acquisition unit 61 acquires the current temperature t detected by the temperature sensor 7 as current information (step S2).
Next, the difference calculation unit 62 calculates a difference Δt (Δt = t−t0) between the initial temperature t0 and the current temperature t (step S3).

Then, the difference determination unit 63 compares the calculated difference Δt with the previous difference stored in the storage unit 65 to determine whether there is a change in the difference, that is, whether a temperature change has occurred. (Step S4).
If it is determined in step S4 that there is no change in the difference, the processes in steps S2 to S3 are repeated.
On the other hand, if it is determined in step S4 that there is a change in the difference, the heating control unit 64 performs heating based on the LUT (Look-Up-Table) stored in the storage unit 65 as follows. The unit 5 is controlled (step S5).

FIG. 5 is a diagram illustrating an example of a table (LUT) stored in the storage unit 65.
This LUT associates the difference Δt with the fluctuation amount of the focal position due to the first lens group 411, and the difference Δt and the fluctuation amount of the focal position due to the second lens group 412. The fluctuation amounts “+” and “−” shown in FIG. 5 indicate the fluctuation amounts in the “+” and “−” directions shown in FIG. 2, respectively. The relationship shown in FIG. 5 can be obtained in advance by experimental results or the like.

For example, the heating control unit 64 controls the heating unit 5 as follows.
Specifically, when the initial temperature t0 is 10 ° C. and the difference Δt between the lens groups 411 and 412 is 10 ° C., that is, when the temperature t of the lens groups 411 and 412 is 20 ° C. (t0 + Δt), The focal position of the projection optical device 4 varies by 20 (20−40 = 20) mm in the “−” direction in FIG. 2. Therefore, in this case, the heating control unit 64 turns on the heater 51, and the temperature of the first lens group 411 is a temperature at which the fluctuation of the focal position of the projection optical device 4 due to the temperature rise, that is, specifically, Is heated to 30 ° C. (“initial temperature t 0 (10 ° C.)” + “Difference Δt (20 ° C.) at which fluctuation amount becomes +40 mm”). The temperature in the heating state can be monitored by the temperature detected by the temperature sensor 7. Thereby, the fluctuation | variation of the said focus position is eliminated.

  It is conceivable that the temperature of each lens group 41 differs depending on the difference in light absorption rate and the like. In this case, the difference Δt may be different between the lens groups 411 and 412. When the initial temperature t0 is 10 ° C., the difference Δt of the lens group 411 is 40 ° C., and the Δt of the lens group 412 is 10 ° C., that is, the temperature t of the lens group 411 is 50 ° C. and the temperature t of the lens group 412 is In the case of 20 ° C., the focal position of the projection optical device 4 varies by 40 (80−40 = 40) mm in the “+” direction in FIG. Therefore, in this case, the heating control unit 64 turns on the heater 52, and the temperature of the second lens group 412 is the temperature at which the fluctuation of the focal position of the projection optical device 4 due to the temperature rise is eliminated as in the case described above. Specifically, the heating is performed so as to be 30 ° C. (“initial temperature t0 (10 ° C.)” + “Difference Δt (20 ° C.) at which the fluctuation amount becomes −80 mm”). Thereby, the fluctuation | variation of the said focus position is eliminated.

  When the difference Δt in the first lens group 411 is 40 ° C. and the difference Δt in the second lens group 412 is 20 ° C., the focal position of the projection optical device 4 does not vary (80−80 = 0). Therefore, in this case, since the focal position does not change, the heating control unit 64 does not need to adjust the temperature of the lens groups 411 and 412.

The heating control unit 64 heats both of the lens groups 411 and 412 using both of the heaters 51 and 52, so that the temperature of the lens groups 411 and 412 of the projection optical apparatus 4 increases with each other. The variation in the focal position may be eliminated by setting the temperature so as to eliminate the variation in the focal position. For example, when the initial temperature t0 is 10 ° C. and the difference Δt between the lens groups 411 and 412 is 10 ° C., that is, when the temperature t of the lens groups 411 and 412 is 20 ° C., the temperature of the lens group 411 is Specifically, heating is performed to be 50 ° C. (“initial temperature t0 (10 ° C.)” + “Difference Δt (40 ° C.) at which the fluctuation amount is +80 mm”), and the temperature of the second lens group 412 is specifically To 30 ° C. (“initial temperature t 0 (10 ° C.)” + “Difference Δt (20 ° C.) at which fluctuation amount becomes −80 mm”). This also eliminates fluctuations in the focal position.
In this way, the control unit 6 acquires the difference Δt as information (variation related information) related to the focal position of the projection optical apparatus 4 associated with the temperature rise by the above-described steps S1 to S3 (information acquisition procedure). The heating unit 5 is controlled based on the acquired difference Δt by the steps S4 and S5 (heating control procedure).

The projector 1 according to the present embodiment described above has the following effects.
When the temperature of the projection optical apparatus 4 rises and the focal position of the projection optical apparatus 4 fluctuates, the first lens group 411 and the first lens group 411 Since at least one of the second lens groups 412 is heated, the variation in the focal position is reduced. Therefore, since the change in the focal position of the projection optical device 4 during use of the projector 1 can be suppressed, a clear image display state can be maintained.
Further, by employing the heaters 51 and 52 as the heating unit 5, it is possible to suppress the generation of noise such as wind noise, and the noise of the projector 1 can be reduced compared to the case where the cooling unit is employed.

  Further, the control unit 6 calculates a difference Δt between the initial temperature t0 acquired at a predetermined timing and the current temperature t acquired after the predetermined timing, and controls the heating unit 5 according to the difference Δt. As a result, the fluctuation amount of the focal position after the predetermined timing with respect to the focal position at the predetermined timing can be determined by the difference Δt, so that the lens groups 411 and 412 can be heated according to the fluctuation amount.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
The projector according to the present embodiment has the same configuration and function as the projector 1 described above, but the control of the heating unit 5 in the heating control unit 64 described above is different from the projector 1. Specifically, the heating control unit 64 in the present embodiment controls the heating unit 5 with reference to the LUT described below in step S5 described above, using the LUT shown in FIG. 5 described above. This is different from the projector 1 that controls the projector 5. In the following description, parts that are the same as or substantially the same as those already described are assigned the same reference numerals and description thereof is omitted.

In the present embodiment, the storage unit 65 stores an LUT in which the difference Δt and the applied voltage to the heater 51 and the difference Δt and the applied voltage to the heater 52 are associated with each other. The relationship between the difference Δt and the applied voltage (V) can be obtained through experiments or the like in advance.
And in this embodiment, the heating control part 64 controls the heating by the heating unit 5 according to the difference (DELTA) t which the difference calculation part 62 calculated. That is, in step S4 described above, when the difference determination unit 63 determines that there is a change in the difference, the heating control unit 64 reads the LUT corresponding to the heater used for heating, and the difference calculated by the difference calculation unit 62 The drive of the heater is controlled with an applied voltage corresponding to Δt. Specifically, the heating control unit 64 performs control so that the voltage applied to the heater used for heating increases as the difference Δt increases. For example, when Δt of the lens groups 411 and 412 is 20 ° C., a voltage of 5 V is applied to the heater 51, and when Δt of the lens groups 411 and 412 is 40 ° C., respectively, Apply a voltage of 15V.

The projector 1 according to the present embodiment described above has the following effects in addition to the same effects as those of the first embodiment described above.
By controlling the heating unit 5 using the LUT in which the difference Δt and the voltage applied to the heaters 51 and 52 are associated with each other, there is no need to monitor the temperature of the lens group being heated, and the heating unit 5 is controlled. It can be simplified.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
In each said embodiment, although the projector 1 was provided with the projection optical apparatus 4 which has the three lens groups 41 (411-413), this invention is not limited to this. That is, the number of lens groups provided in the projection optical apparatus can be set as appropriate based on the characteristics, performance, manufacturing cost, and the like of the projection optical apparatus.

In each of the embodiments, the heaters 51 and 52 are provided in the lens barrel 42. However, the present invention is not limited to this, and the heater 51 and 52 can be installed in any place as long as the corresponding lens group 41 and lens barrel 42 can be heated. Either the inside or outside of the lens barrel 42 may be used.
In each of the embodiments, the lens groups 411 and 412 are provided with the heaters 51 and 52, respectively, and either one is heated, but the present invention is not limited to this. For example, if it is known that the temperature fluctuates on either the positive side or the negative side due to a temperature rise, a heater may be provided only on one of them. Furthermore, a heater may be installed so as to correspond to three or more lens groups, and the focal position may be adjusted by controlling the operation of two or more heaters.
In each of the embodiments described above, the temperature in the vicinity of the lens groups 411 and 412 is detected as the temperature of the projection optical device 4, but is not limited thereto. For example, the temperature sensor 7 may be provided in the lens barrel 42 to directly detect the temperatures of the lens groups 411 and 412.

In each of the above-described embodiments, the predetermined timing is set when the user adjusts the focal position of the projection optical device 4. However, the present invention is not limited to this, and may be after the temperature of each lens group 41 is stabilized. .
In each of the above embodiments, the information acquisition unit 61 uses the temperature information detected by the temperature sensor 7 to acquire the fluctuation related information, but the present invention is not limited to this. For example, an elapsed time from the start of lighting of a light source used for image formation by a timer or the like may be acquired, and various processes may be performed based on the elapsed information. Further, for example, an APL (Average Picture Level) of an image projected through the projection optical apparatus may be acquired, and various processes may be performed based on the APL. In this case, an LUT in which the elapsed time, APL, and the focal position fluctuation amount are associated with each other may be used.
In the second embodiment, the voltage applied to the heater used for heating is controlled according to the difference Δt, but the control according to the difference Δt is not limited to this. For example, the set temperature of the heater, the heating time, and the like may be controlled according to the difference Δt.

  In each of the above embodiments, a projector using three light modulation devices is employed. However, the present invention is not limited to this. For example, a projector using only one light modulation device, a projector using two light modulation devices, or 4 A projector using two or more light modulation devices may be used. Moreover, although the liquid crystal panel was employ | adopted as a light modulation apparatus, you may employ | adopt light modulation apparatuses other than liquid crystals, such as a device using not only this but a micromirror. Further, instead of a transmissive light modulator, a reflective light modulator may be used.

  In each of the above embodiments, the projector 1 is configured as a front type projector in which the projection direction of the image on the projection surface and the observation direction of the image are substantially the same, but the present invention is not limited to this. For example, the present invention can be applied to a rear type projector in which the projection direction and the observation direction are opposite directions.

  The present invention can be used for a projector having a projection optical device that projects a formed image.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 4 ... Projection optical apparatus, 5 ... Heating unit (heating means), 6 ... Control unit (control means), 61 ... Information acquisition part, 64 ... Heating control part, 411 ... 1st lens group, 412 ... 1st 2 lens groups.

Claims (3)

A projector comprising a projection optical device for projecting an image,
The projection optical device has a first lens group whose focal position changes to a position far from the projection optical apparatus in response to a temperature rise, and a second lens group that changes to a close position,
The projector is
Heating means for heating at least one of the first lens group and the second lens group;
Control means for controlling the heating means,
The control means controls the heating means so as to eliminate the fluctuation of the focal position of the projection optical apparatus due to a temperature rise. The projector according to claim 1.
The control means includes
An information acquisition unit that respectively acquires fluctuation-related information related to fluctuations in the focal position of the projection optical apparatus accompanying a temperature increase in the first lens group and the second lens group;
Heating that calculates the difference between the fluctuation-related information acquired by the information acquisition unit at a predetermined timing and the fluctuation-related information acquired by the information acquisition unit after the predetermined timing, and controls the heating unit according to the difference And a control unit. A method for adjusting a focus of a projection optical device, comprising:
The projection optical apparatus according to the temperature increase in the first lens group that the focal position of the projection optical apparatus changes to a position far from the projection optical apparatus and the second lens group that changes to a close position in accordance with the temperature increase. An information acquisition procedure for acquiring variation-related information regarding the variation of the focal position of each,
Heating means for heating at least one of the first lens group and the second lens group so as to eliminate the fluctuation of the focal position of the projection optical apparatus due to the temperature rise based on the fluctuation related information. And a heating control procedure for controlling the focus adjustment method.

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