JP2015225213A - Image projection device and program for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform excellent cooling, without increasing the size of a fan, in an image projection device.SOLUTION: The image projection device projects an image by using light from a light source 1 and can select a plurality of projection modes different in projection brightness and a plurality of installation attitudes. The device includes control means 12 and 9 for controlling electric power supplied to the light source and temperature detection means 10 for detecting the ambient temperature of the device. The control means change the electric power, according to the fact that the ambient temperature detected by the temperature detection means reaches a threshold. The control means change the threshold, according to at least one of the selected installation attitude and the selected projection mode.

Description

  The present invention relates to an image projection apparatus such as a liquid crystal projector.

  The above image projection devices are used for various applications such as presentations, home theaters, planetariums, etc., and select multiple projection modes so that the brightness (projection brightness) of the projected image can be obtained according to each application Many are possible. Also, with respect to the method of installing the image projection apparatus, a plurality of installation postures such as stationary, ceiling suspension, upward and downward can be selected. On the other hand, light sources (lamps) and optical elements (liquid crystal panels, polarizing plates, etc.) that generate heat are disposed inside the image projection apparatus, and these need to be sufficiently cooled. An electric fan for generating an air flow is generally used for cooling in the image projection apparatus. The rotation speed of the fan is often controlled according to the ambient temperature (environment temperature) of the image projection apparatus. Specifically, the rotational speed of the fan is increased or decreased according to the increase or decrease of the environmental temperature detected by the temperature sensor to a predetermined temperature threshold.

  However, the cooling efficiency (particularly the exhaust efficiency) of the image projection apparatus varies depending on the installation posture. Although it is possible to increase the size of the fan so that sufficient cooling can be performed even in an installation posture where the cooling efficiency is not high, there is a problem in that this increases the size of the entire apparatus.

  Patent Document 1 discloses an image projection apparatus that changes the output of a light source in a stepwise manner according to the environmental temperature detected by a temperature sensor.

JP 2003-43585 A

  However, just by changing the output of the light source stepwise according to the environmental temperature as in the image projection apparatus disclosed in Patent Document 1, the brightness (projection luminance) of the projected image is frequently accompanied by a change in the environmental temperature. It may darken or become brighter and may cause discomfort to the viewer. Further, when a plurality of projection modes can be selected, it may not be appropriate to change the output of the light source at the same environmental temperature regardless of the projection mode. For example, the original light source setting output is different between a presentation projection mode for projecting a bright image and a home theater projection mode for projecting a dark image. If the output of the light source is changed at the same environmental temperature in these projection modes, the cooling becomes insufficient in the former projection mode, or the image becomes too dark although the cooling is sufficient in the latter projection mode.

  The present invention provides an image projecting apparatus and a control program for the image projecting apparatus that can perform good cooling without increasing the size of a fan.

  An image projection apparatus according to an aspect of the present invention projects an image using light from a light source, and can select a plurality of projection modes having different projection luminances and can select a plurality of installation postures. The image projection apparatus includes a control unit that controls electric power supplied to the light source, and a temperature detection unit that detects an ambient temperature of the image projection apparatus. The control means changes the power in response to the ambient temperature detected by the temperature detection means reaching a threshold value. Furthermore, the control means changes the threshold according to at least one of the selected installation posture and the selected projection mode.

  In addition, a control program according to another aspect of the present invention projects an image using light from a light source, and can select a plurality of projection modes having different projection luminances and a plurality of installation postures. A computer program for causing a computer provided in a simple image projection apparatus to control power supplied to a light source. The control program acquires the ambient temperature of the image projection apparatus, and changes the power in response to the acquired ambient temperature reaching a threshold value. Furthermore, the control program changes the threshold value according to at least one of the selected installation posture and the selected projection mode.

  According to the present invention, since the ambient temperature threshold value for changing the power supplied to the light source (light source output) is changed according to the projection mode and the installation posture, the ambient temperature can be changed without increasing the size of the fan. The change of the output of the accompanying light source can be performed appropriately. Thereby, the inside of the image projection apparatus can be favorably cooled in each projection mode and each installation posture.

1 is a diagram illustrating a configuration of a liquid crystal projector that is Embodiment 1 of the present invention. FIG. FIG. 3 is a block diagram illustrating a configuration for controlling lamp output in the first embodiment. 5 is a flowchart illustrating processing for setting a temperature threshold in the first embodiment. 5 is a flowchart illustrating processing for controlling lamp output in the first embodiment. The figure which shows the correction value for every installation attitude | position for correcting the temperature threshold value in Example 1, and projection mode. The figure which shows the temperature threshold value for every combination of the installation attitude | position and projection mode in Example 1. FIG. 3 is a flowchart illustrating processing for controlling lamp output and fan rotation speed in the first embodiment.

Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of a liquid crystal projector (hereinafter simply referred to as a projector) as an image projection apparatus that is Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a lamp (discharge arc tube) as a light source, and an ultrahigh pressure mercury lamp or the like is used. In addition, you may use light-emitting bodies other than a lamp, such as LED and a laser element, as a light source. α denotes an illumination optical system that guides light from the lamp 1 to the color separation / synthesis optical system β. The illumination optical system α includes a polarization separation element that converts non-polarized light from the lamp 1 into linearly polarized light, a fly-eye lens that divides the light from the lamp 1 into a plurality of light beams, and the plurality of divided light beams, which will be described later. A condenser lens or the like to be superimposed on the liquid crystal panel is included.

  The color separation / synthesis optical system β splits the white light from the illumination optical system α into red (R) light, green (G) light, and blue (B) light, and R, G, and B light modulation elements To a liquid crystal panel (not shown). Further, the color separation / synthesis optical system β combines the R light, G light, and B light modulated by the liquid crystal panel and guides them to the projection lens (projection optical system) 2. The projection lens 2 guides the combined RGB light to a projection surface such as a screen (not shown).

  Reference numeral 3 denotes an air inlet as an opening formed in the housing 13 of the projector, and includes an air filter (not shown) for preventing dust from entering the housing 13. In addition to the lamp 1, the illumination optical system α, and the color separation / synthesis optical system β, the housing 13 includes cooling fans 4, 5, 6, an exhaust fan 7, a power supply unit 8, a power change unit 9, a main controller 12, a temperature, The sensor 10 and the attitude sensor 11 are accommodated.

  Among the cooling fans 4 to 6, 4 is a lamp cooling fan for cooling the lamp 1 which is a heating element. Reference numeral 5 denotes an illumination system cooling fan that cools the illumination optical system α (mainly a polarization conversion element or the like) with air (outside air) taken from the intake port 3. Reference numeral 6 denotes a color separation / synthesis cooling fan that cools the color separation / synthesis optical system β (mainly a liquid crystal panel or a polarizing plate serving as a heating element) including the liquid crystal panel by air taken in from the air inlet 3. Reference numeral 7 denotes an exhaust fan that exhausts air that has been used for cooling in the housing 13 and has become hot to the outside of the housing.

  FIG. 2 shows a configuration of a light source power control system that includes the main controller 12, the power changing unit 9, the power supply unit 8, the temperature sensor 10, and the attitude sensor 11 and that controls the power supplied to the lamp 1.

  The power supply unit 8 supplies power for light emission to the lamp 1. The power changing unit 9 changes the power supplied from the power supply unit 8 to the lamp 1 according to a command signal from the main controller 12 described later.

  The temperature sensor 10 is a temperature sensor as temperature detecting means for detecting an ambient temperature (hereinafter referred to as an environmental temperature) that is a temperature around the projector. The temperature sensor 10 is composed of an IC that outputs a voltage proportional to the environmental temperature. The temperature sensor 10 is preferably disposed at a position where the ambient temperature around the housing 13 can be accurately detected, for example, in the vicinity of the air inlet 3.

  The attitude sensor 11 is composed of an IC that detects the attitude of the projector and outputs an electrical signal. Depending on the output from the attitude sensor 11, the projector installation method (installation attitude) can be either a stationary installation on a desk, a ceiling hanging upside down from the ceiling, or an image projected onto the ceiling It is possible to determine whether the image is upward or the image is projected downward toward the floor.

  Note that the posture sensor 11 is not necessarily provided, and the user selects (inputs) whether the installation posture is stationary, ceiling-mounted, upward, or downward through an operation unit (for example, an on-screen operation menu) of the projector. Also good.

  The main controller 12 is a computer composed of a CPU, a ROM, and the like. The main controller 12 controls the power supplied to the lamp 1, that is, the output of the lamp 1, through the power supply controller 9 described above, and controls all other operations in the projector according to the computer program. The main controller 12 and the power supply controller 9 constitute control means.

  The main controller 12 controls the power supplied to the lamp 1 (the output of the lamp 1) according to the projection mode selected by the user through the operation unit. In this embodiment, there are a standard mode, a presentation mode, and a cinema mode as a plurality of projection modes, and the user selects a projection mode according to the application from these.

  FIG. 5 shows a comparison between the required brightness of the projected image (projection luminance) required in the standard mode, presentation mode, and cinema mode and the quietness required for the operation sound of the projector (mainly the sound emitted from the cooling fan). Yes. The standard mode is a standard projection mode of the projector, and the projection brightness and silence in this standard mode are standard (represented by “medium” and “◯”, respectively).

  The presentation mode is a projection mode suitable for a presentation performed by projecting a clear image in a bright conference room. The projection brightness required in this presentation mode is higher than that in the standard mode, and the required quietness is lower than that in the standard mode (Δ).

  The cinema mode is a projection mode suitable for viewing an image such as a movie in a dark room. The projection brightness required in this presentation mode is lower than that in the standard mode, and the required quietness is higher than in the standard mode (（).

  Next, control of the output of the lamp 1 (hereinafter referred to as lamp output) performed by the main controller 12 through the power changing unit 9 will be described with reference to the flowcharts of FIGS. The main controller 12 executes this control according to a power control program that is a computer program.

  First, the setting process of the temperature thresholds TH1 and TH2 used for controlling the lamp output will be described with reference to the flowchart shown in FIG. In step S <b> 1, the main controller 12 detects the installation posture of the projector based on the output from the posture sensor 11. As described above, when the installation posture is input by a user operation, the main controller 12 captures the input installation posture in this step.

  Next, in step S2, the main controller 12 determines whether or not the detected (or captured) installation posture is stationary. If it is deferred, the process proceeds to step S5, and if it is not deferred, the process proceeds to step S3.

  In step S3, the main controller 12 determines whether or not the installation posture is suspended from the ceiling. If it is a ceiling suspension, it will progress to step S6, and if it is not a ceiling suspension, it will progress to step S4.

  In step S4, the main controller 12 determines whether or not the installation posture is upward. If it is upward, the process proceeds to step S7. If it is not upward, that is, it is downward, the process proceeds to step S8.

  In step S3, the main controller 12 sets 1 to the attitude flag FA. Similarly, in steps S6, S7, and S8, the main controller 12 sets 2, 3, and 4 to the attitude flag FA.

  Next, in step S9, the main controller 12 determines whether or not the currently set projection mode is the standard mode. If it is the standard mode, the process proceeds to step S11, and if it is not the standard mode, the process proceeds to step S10.

  In step S10, the main controller 12 determines whether or not the currently set projection mode is the presentation mode. If it is the presentation mode, the process proceeds to step S12. If it is not the presentation mode, that is, if it is the cinema mode, the process proceeds to step S13.

  In step S11, the main controller 12 sets 1 to the mode flag FM. Similarly, in steps S12 and S13, the main controller 12 sets 2 and 3 to the mode flag FM, respectively.

  Next, in step S14, the main controller 12 sets a temperature threshold corresponding to the combination of the attitude flag FA and the mode flag FM, that is, the combination of the installation attitude and the projection mode. In this embodiment, as the temperature threshold, the temperature threshold (first threshold) TH1 used when the environmental temperature detected by the temperature sensor 10 (hereinafter also referred to as a detected temperature) is increasing, and the detected temperature decreases. Temperature threshold value (second threshold value) TH2 to be used. TH1 is a temperature at which the lamp output is lowered when the detected temperature rises and reaches this temperature. TH2 is a temperature at which the lamp output is increased when the detected temperature decreases and reaches this level. TH1 and TH2 have a relationship of TH1> TH2 regardless of the combination of the installation posture and the projection mode.

  In this way, by changing the temperature threshold value used when the detected temperature rises and falls, the projection output brightness that causes the user to feel uncomfortable by repeating the slight increase / decrease in the environmental temperature and the increase / decrease in the lamp output is repeated. The occurrence of repeated fluctuations can be avoided.

  FIG. 5 shows TH1 and TH2 for each combination of installation posture and projection mode. The reason why TH1 and TH2 are made different according to the installation posture is that, due to the positional relationship of the exhaust fan 7 provided in a part of the housing 13, a difference in exhaust efficiency by the exhaust fan 7 occurs depending on the installation posture. In the projector of this embodiment, the exhaust fan 7 is disposed on the opposite side of the housing 13 from the projection lens 2 and exhausts in the direction opposite to the image projection direction from the projection lens 2. For this reason, as shown in FIG. 5, the exhaust efficiency for both stationary and ceiling suspensions is a standard value (“medium”). Compared to these, the exhaust efficiency in the upward direction is low, and the exhaust efficiency is in the downward direction. Efficiency is high.

  Also, the reason why TH1 and TH2 are made different according to the projection mode is that the projection brightness required for each projection mode is different from each other as described above. This is because more heat is generated from the synthetic optical systems α and β.

  In the present embodiment, TH1 and TH2 in the standard mode for stationary and ceiling suspension are respectively assumed to be standard values A and B (where A> B). On the other hand, TH1 and TH2 in the presentation mode in which the projection brightness is higher than the standard mode in the same stationary and ceiling suspension are respectively set as Ax and Bx lower than A and B. On the other hand, TH1 and TH2 in the cinema mode (second projection mode) where the projection brightness is lower than that in the standard mode (first projection mode) in the same stationary and ceiling suspension are respectively higher than A and B, A + y and B + y. And x and y are correction values for correcting A and B in the presentation mode and the cinema mode, respectively.

  In addition, TH1 and TH2 in the upward standard mode, which has lower exhaust efficiency than stationary and ceiling suspension, are An and Bn, which are lower than A and B, respectively. On the other hand, TH1 and TH2 in the same upward presentation mode and cinema mode are denoted as Anx, Bnx, and An + y, Bn + y, respectively. n is a correction value for correcting A and B in the upward direction.

  Furthermore, TH1 and TH2 in the downward standard mode, which has higher exhaust efficiency than stationary and ceiling suspension, are set to A + m and B + m higher than A and B, respectively. On the other hand, TH1 and TH2 in the same downward presentation mode and cinema mode are A + mx, B + mx, and A + m + y, B + m + y, respectively. m is a correction value for correcting A and B in the downward direction.

  FIG. 6A shows TH1 = A and TH2 = B in the standard mode for stationary and ceiling suspension. FIG. 6B shows TH1 = Ax and TH2 = Bx in the presentation mode for stationary and ceiling suspension, and TH1 = A + y and TH2 = B + y in the cinema mode for stationary and ceiling suspension. ing. FIG. 6C shows TH1 = A−n and TH2 = B−n in the upward presentation mode. FIG. 6D shows TH1 = A + m and TH2 = B + m in the downward presentation mode.

  Thus, in this embodiment, the temperature thresholds TH1 and TH2 that decrease and increase the lamp output are corrected (changed) in accordance with the combination of the installation posture and the projection mode.

  In addition, although the present Example demonstrates the case where a temperature threshold value is changed according to both an installation attitude | position and projection mode, you may change a temperature threshold value according to one of an installation attitude | position and projection mode. That is, the above-described effect can be obtained by changing the temperature threshold according to at least one of the installation posture and the projection mode.

  Finally, in step S15, the main controller 12 determines whether or not the projection mode has been changed by the user through the operation unit. When the projection mode is changed, the process returns to step S9 to update the mode flag (steps S9 to S13), and in step S14, temperature thresholds TH1 and TH2 corresponding to the new projection mode are set.

  Next, a lamp output control process using the temperature thresholds TH1 and TH2 set as described above will be described with reference to the flowchart shown in FIG. In step S <b> 21, the main controller 12 acquires (detects) the current environmental temperature Tc as the detected temperature through the temperature sensor 10.

  In step S22, the main controller 22 calculates a difference ΔT between the current environmental temperature Tc and the previously acquired environmental temperature Tp. After that, the main controller 12 stores the current environmental temperature Tc as the previous environmental temperature Tp used for the calculation in the next step S22.

  Next, in step S23, the main controller 12 determines whether or not ΔT calculated in step S22 is positive (+), that is, whether or not the current environmental temperature Tc has increased with respect to the previous environmental temperature Tp. . If the main controller 12 determines that the environmental temperature Tc has increased, the process proceeds to step S24. If ΔT is negative (−), that is, if the current environmental temperature Tc has decreased with respect to the previous environmental temperature Tp. Proceed to step S25. When ΔT is 0, the main controller 12 returns to step S21 and again detects the current (next) environmental temperature Tc.

  In step S24, the main controller 12 determines whether or not the current environmental temperature Tc is equal to or higher than the temperature threshold TH1 (whether or not it has reached the temperature threshold TH1). If Tc is greater than or equal to TH1, the process proceeds to step S26, and if not, the process returns to step S21.

  In step S <b> 26, the main controller 12 reduces the power supplied to the lamp 1 through the power changing unit 9 by a predetermined amount, thereby reducing the lamp output. Then, the process returns to step S21.

  On the other hand, in step S25, the main controller 12 determines whether or not the current environmental temperature Tc is equal to or lower than the temperature threshold value TH2 (whether or not it has reached the temperature threshold value TH2). If Tc is equal to or less than TH2, the process proceeds to step S27, and if not, the process returns to step S21.

  In step S27, the main controller 12 increases the power supplied to the lamp 1 through the power changing unit 9 by a predetermined amount to increase the lamp output. Then, the process returns to step S21.

  As described above, in this embodiment, the temperature thresholds TH1 and TH2 are corrected (changed) in accordance with at least one of the selected installation posture and the selected projection mode. For this reason, without changing the size of the cooling fan or exhaust fan, the lamp output is appropriately changed in accordance with the environmental temperature fluctuation in each installation posture and each projection mode, and the inside of the projector (heating element) is cooled well. Can be done.

  Next, a second embodiment of the present invention will be described. Since the configuration of the projector in the present embodiment is the same as that in the first embodiment, the same reference numerals as those in the first embodiment are given to the respective components.

  In the first embodiment, the case where the lamp output is decreased or increased immediately in response to the current environmental temperature Tc reaching the temperature threshold value TH1 or the temperature threshold value TH2 has been described. However, the rotation speeds of the cooling fans 4 to 6 and the exhaust fan 7 may be increased or decreased before the lamp output is changed. However, in the cinema mode, a higher silence and a projection brightness that is not too bright are required compared to the standard mode and the presentation mode. For this reason, the lamp output is decreased without increasing the rotational speed of the cooling fans 4 to 6 and the exhaust fan 7 (hereinafter referred to as fan rotational speed), or the fan rotational speed is decreased without increasing the lamp output. You may do it.

  The flowchart of FIG. 7 shows the control processing of the lamp output and the fan rotation speed in the present embodiment using the temperature thresholds TH1 and TH2 set in the same manner as in the first embodiment. Note that steps S21 to S27 in FIG. 7 are the same as steps S21 to S27 shown in FIG.

  The main controller 12 having determined that the current environmental temperature Tc is equal to or higher than the temperature threshold value TH1 in step S24 determines whether or not the currently set projection mode is the cinema mode in step S31. When the current projection mode is the cinema mode, the main controller 12 proceeds to step S26 and decreases the lamp output. On the other hand, if the current projection mode is not the cinema mode (standard mode or presentation mode), the process proceeds to step S32.

  In step S32, the main controller 12 confirms whether or not the fan speed can be increased, that is, whether or not the current fan speed has reached the maximum. If the fan speed can be increased, the main controller 12 proceeds to step S33, otherwise proceeds to step S26 to reduce the lamp output.

  In this way, in the standard and presentation modes where high silence is not required, the fan rotation speed is first increased before the lamp output is reduced, so that the projector can be cooled well while maintaining bright projection brightness. it can. On the other hand, by reducing the lamp output without increasing the fan rotation speed in the cinema mode, the inside of the projector can be favorably cooled while maintaining high silence.

  In step S33, the main controller 12 increases the fan output by a predetermined amount. Then, the process returns to step S21.

  In step S25, the main controller 12 having determined that the current environmental temperature Tc is equal to or lower than the temperature threshold value TH2 determines in step S34 whether or not the currently set projection mode is the cinema mode. If the current projection mode is not the cinema mode, the main controller 12 proceeds to step S27 and increases the lamp output. On the other hand, if the current projection mode is the cinema mode, the process proceeds to step S35.

  In step S35, the main controller 12 checks whether or not the fan output can be reduced, that is, whether or not the current fan output is in the lowest state. If the fan output can be reduced, the main controller 12 proceeds to step S36, otherwise proceeds to step S27 to increase the lamp output.

  In step S36, the main controller 12 decreases the fan output by a predetermined amount. Then, the process returns to step S21.

  As described above, in the standard and presentation modes where brighter projection brightness is preferred, the lamp output is increased without lowering the fan speed. Thereby, even when the lamp output once decreases in step S26, the desired projection luminance can be recovered early. On the other hand, by lowering the fan speed first before increasing the lamp output in the cinema mode, it is possible to cool the inside of the projector satisfactorily while ensuring projection brightness that is not too bright and higher noise reduction.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

1 Lamp 9 Power Changer 10 Temperature Sensor 11 Attitude Sensor 12 Main Controller

Claims (6)

An image projection apparatus that projects an image using light from a light source and is capable of selecting a plurality of projection modes with different projection luminances and capable of selecting a plurality of installation postures,
Control means for controlling the power supplied to the light source;
Temperature detecting means for detecting the ambient temperature of the image projection device,
The control means changes the power in response to the ambient temperature detected by the temperature detection means reaching a threshold value,
An image projection apparatus, wherein the threshold value is changed according to at least one of the selected installation posture and the selected projection mode. The threshold includes a first threshold used when the ambient temperature increases and a second threshold used when it decreases.
The image projector according to claim 1, wherein the controller changes both the first and second thresholds according to at least one of the selected installation posture and the selected projection mode. A fan for cooling the inside of the image projection apparatus;
3. The image projection according to claim 1, wherein the control unit changes a rotation speed of the fan according to at least one of the selected installation posture and the selected projection mode. 4. apparatus. As said projection mode, it has the 1st projection mode and the 2nd projection mode in which quietness is calculated | required rather than this 1st projection mode,
The control means includes
When the first projection mode is selected, the rotational temperature of the fan is increased in response to the ambient temperature increasing and reaching the threshold,
4. The image projection apparatus according to claim 3, wherein when the second projection mode is selected, the power is decreased in response to the ambient temperature increasing and reaching the threshold value. 5. As said projection mode, it has the 1st projection mode and the 2nd projection mode in which quietness is calculated | required rather than this 1st projection mode,
The control means includes
When the first projection mode is selected, the power is increased in response to the ambient temperature decreasing and reaching the threshold;
4. The image projection according to claim 3, wherein when the second projection mode is selected, the rotation speed of the fan is decreased in response to the ambient temperature decreasing and reaching the threshold value. 5. apparatus. Projects an image using light from a light source and supplies the light source to a computer provided in an image projection apparatus capable of selecting a plurality of projection modes having different projection brightness and capable of selecting a plurality of installation postures. A computer program for controlling the power to be generated,
Obtaining the ambient temperature of the image projection device;
Changing the power in response to the acquired ambient temperature reaching a threshold;
A control program for an image projection apparatus, wherein the threshold value is changed according to at least one of the selected installation posture and the selected projection mode.