JP2014235220A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device that does not cause discomfort of a user, and enables an enhanced life of an optical element including an image conversion element.SOLUTION: The projection type display device comprises: an image conversion element; an illumination optical system that illuminates the image conversion element; a projection optical system that projects light converted by the image conversion element to a projected plane; a cooling fan; and control means that controls the number of rotations of the fan. The control means controls the fan in a first mode that makes the number of rotations of the fan stationary in a first environment temperature area, and controls the fan in a second mode that changes the number of rotations of the fan from the number of rotations in the first mode in a second environment temperature area different from the first environment temperature area.

Description

  The present invention relates to a projection display device such as a liquid crystal projector provided with a cooling fan for cooling a heat generating part in the device.

  In recent years, the demand for projection display devices typified by liquid crystal projectors is rapidly expanding. As demand increases, there are various uses such as presentations, home theaters, planetariums, and the specifications and functions vary depending on the purpose. Examples of required specifications include a lightweight model pursuing portability and a high luminance model pursuing image quality.

  Furthermore, with regard to the usage environment and cooling fan output, the amount of noise change is 1 dB or less at time intervals of 10 seconds or more so that the change in sound is not uncomfortable when watching a quiet scene of a movie. A model in which the fan output is changed step by step is also known (Patent Document 1).

JP 2006-58804 A

  Here, in various usage environments, when the output of the cooling fan that cools the heat generating part in the apparatus is always constant, the heat generating part (for example, an optical element including an image modulation element) is used in a high temperature environment. ) Also rises, and the lifetime of the optical element including the image modulation element is shortened. On the other hand, if the fan output is constantly changed according to the environmental temperature, the noise from the fan increases as the environmental temperature rises, and there is a concern that the user may feel the sound change uncomfortable.

An object of the present invention is to provide a projection display device that does not cause discomfort to the user and can extend the life of an optical element including an image modulation element.

  To achieve the above object, a projection display apparatus according to the present invention projects an image modulation element, an illumination optical system that illuminates the image modulation element, and light modulated by the image modulation element onto a projection surface. A projection optical system; a cooling fan; and control means for controlling the rotational speed of the fan. The control means is configured to make the rotational speed of the fan constant in a first environmental temperature region. The fan is controlled in a mode, and the fan is controlled in a second mode in which the rotational speed of the fan is changed from the rotational speed in the first mode in a second environmental temperature region different from the first environmental temperature region. It is characterized by that.

ADVANTAGE OF THE INVENTION According to this invention, a user's discomfort is not produced and the lifetime of the optical element containing an image modulation element can be achieved.

FIG. 5A is a relationship diagram between an environmental temperature and a fan output in the projection display apparatus according to the embodiment of the invention, and FIG. 5B is a flowchart of fan drive control. 1 is a schematic diagram of a cooling configuration of a projection display device according to an embodiment of the present invention. 1 is a schematic configuration diagram of a color separation / synthesis optical system according to an embodiment of the present invention. It is a block block diagram regarding the fan drive control of the projection type display apparatus which concerns on embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<< First Embodiment >>
(Projection type display device)
The projection display apparatus according to the first embodiment of the present invention will be described below with reference to FIGS. In FIG. 2, which is a schematic diagram of the cooling configuration of the projection display device, and in FIG. 3, which is a schematic diagram of the configuration of the color separation / combination optical system, α is an illumination optical system that receives light from the lamp 1 (common to a plurality of image modulation elements). ). Further, β is a color separation / synthesis optical system provided with image modulation elements (liquid crystal panels) for three colors of R, G, and B that receive light emitted from the illumination optical system.

  In FIG. 2, reference numeral 1 denotes a lamp as a light source (for example, a halogen lamp, a xenon lamp, a metal halide lamp, or an ultrahigh pressure mercury lamp). Reference numeral 2 denotes a projection lens unit serving as a projection optical system for projecting an image on a screen (projected surface) (not shown) upon incidence of light emitted from the color separation / synthesis optical system β.

  In FIG. 3, the illumination light transmitted through the polarization separation element 30 is separated into light of a plurality of wavelength bands by the cross dichroic prism 15. The dichroic film 15a has a characteristic of reflecting light in the blue wavelength band and transmitting light in the red and green wavelength bands. The dichroic film 15b has a characteristic of reflecting light in the red wavelength band and transmitting light in the blue and green wavelength bands. That is, light in the blue wavelength band of the illumination light is reflected by the dichroic film 15a, and light in the red wavelength band is reflected by the dichroic film 15b. Light in the green wavelength band is transmitted through both the dichroic film 15a and the dichroic film 15b.

  As a result, the illumination light is separated into light 16r in the red wavelength band, light 16g in the green wavelength band, and light 16b in the blue wavelength band indicated by a thin solid line in FIG. The light 16r, 16b, and 16g (hereinafter also referred to as color light) in each wavelength band illuminate the image display elements 18r, 18g, and 18b (light modulation elements) corresponding to the respective color lights.

  The image display elements 18r, 18g, and 18b are elements that change (modulate) and reflect the polarization state of illumination light according to an image signal. The image lights 19r, 19g, and 19b (thin broken lines) reflected by the image display elements 18r, 18g, and 18b enter the cross dichroic prism 15 again. The image light 19b in the blue wavelength band passes through the dichroic film 15b, is reflected by the dichroic film 15a, and is emitted to the polarization separation element 30 side.

  The image light 19r in the red wavelength band passes through the dichroic film 15a, is reflected by the dichroic film 15b, and is emitted to the polarization separation element 30 side. The image light 19g in the green wavelength band passes through both the dichroic film 15a and the dichroic film 15b and is emitted to the polarization separation element 30 side.

  As described above, the image lights 19r, 19g, and 19b are combined by the dichroic film 15a and the dichroic film 15b, and are emitted from the cross dichroic prism 15 as the combined image light 25 (thick broken line in FIG. 1). The emitted synthetic image light 25 is guided to the projection lens unit 2 by the polarization separation element 30 and projected onto the screen (projection surface). The polarization separation element 30, the cross dichroic prism 15, and the phase difference plates 17r, 17g, and 17b are color separation / combination optical systems.

  Returning to FIG. 2, reference numeral 3 denotes an intake port including an air filter (not shown) that suppresses dust from entering the housing when the outside air is inhaled. Reference numeral 4 denotes a lamp cooling fan for cooling the lamp 1, and 5 denotes an illumination optical system cooling fan for cooling the illumination optical system α, which is the air sucked in outside air from the air inlet 3. Reference numeral 6 denotes air that sucks outside air from the air inlet 3, a color separation / synthesis optical system cooling fan for cooling the color separation / synthesis optical system β, and 7, exhaust that exhausts high-temperature air inside the enclosure to the outside of the enclosure. I am a fan. In addition, 8 is the exterior cabinet for accommodating the members 1-7 mentioned above.

  The projection display device according to the present embodiment is conceptually expressed as follows. That is, a plurality of image modulation elements corresponding to different color lights are illuminated with a first optical system (α, β) that illuminates each image modulation element with different color light and the first optical system. A second optical system (β) for synthesizing different color lights from a plurality of image modulation elements is provided. Furthermore, a projection optical system (2) for projecting light modulated by a plurality of image modulation elements via the first optical system and the second optical system onto the screen surface is provided.

  And the fan (4, 5, 6, 7) which cools the heat-emitting part in an apparatus and the control means (22) which control the rotation speed of a fan are provided. The control means includes a first mode in which the rotational speed of the fan is made constant in the first environmental temperature region, a second mode in which the rotational speed of the fan is changed in a second environmental temperature region different from the first environmental temperature region, Do one of the following: In addition, said 1st optical system illuminates each image modulation element with a different color light by color-separating after passing through the 1st illumination optical system and the 1st illumination optical system common to each image modulation element A second illumination optical system.

(Fan control method)
Next, FIG. 4 shows a block configuration related to the above-described four fans, that is, three cooling fans (the lamp cooling fan 4, the illumination optical cooling fan 5, and the color separation / synthesis optical system cooling fan 6) and the exhaust fan 7. Will be explained. Reference numeral 20 denotes a temperature sensor as environmental temperature detection means for detecting the environmental temperature in which the apparatus is installed. Here, the temperature sensor 20 is an IC that outputs a voltage proportional to the temperature, and is provided at a position that appropriately detects the ambient temperature of the exterior cabinet 8. For example, the vicinity of the intake port 3 is preferable as the installation position of the temperature sensor 20.

  An A / D converter 21 is an electronic circuit that converts an analog electrical signal into a digital electrical signal. The analog electric signal as a detection result output from the temperature sensor 20 is converted into a digital electric signal via the A / D converter 21 and input to the control device 22. The control device 22 is configured by a CPU, a ROM, and the like, and performs operation control of the plurality of cooling fans described above according to a program stored in the control device 22.

  23A, 23B, and 23C are integrators, and the output obtained by the PWM control (pulse width modulation control) from the control device 22 is converted into analog via the integrator 23 and input to the drivers 24A, 24B, and 24C. The drivers 24A, 24B, and 24C are electronic circuits that have a function of supplying power to the plurality of fans described above to operate them and shut them off.

  Here, with respect to the fan output, a ratio (= fan duty) between the time of one cycle in PWM (pulse width modulation) control and the time of pulse HIGH (high level) (time when the pulse is turned on) is involved. The fan speed is changed by changing the fan duty.

(Fan control method when environmental temperature changes)
Next, the details of the fan control method when the environmental temperature changes will be described with reference to the flowchart of FIG. The control device 22 acquires the environmental temperature from the temperature sensor 20 at regular time intervals, and determines whether to change the fan output according to the result. When the environmental temperature is equal to or higher than the threshold value, the fan drive duty is determined by adding the value obtained by multiplying the temperature proportional constant A of each fan by the difference ΔT between the detected temperature and the threshold to the normal drive duty of each fan. When the environmental temperature is lower than the threshold value, the normal driving duty of each fan is set.

  Here, as a threshold value for determining whether or not to change the fan output, it is generally desirable to set the threshold value to be equal to or higher than the upper limit value of the environmental temperature spent by the user. For example, Article 5 (3) of the Sanitary Standard Regulations stipulates that efforts must be made to bring the room temperature of the establishment to 17 to 28 ° C. Accordingly, it is assumed that the user is generally within the room temperature, and it is rare that the user is in the vicinity of the projector in an environment exceeding 30 ° C.

  For this reason, for example, by setting 30 ° C. as a threshold value, in a temperature region where the user is 30 ° C. or less (first environmental temperature region), the fan is driven with a constant fan duty, so that the noise becomes constant and the noise changes. There is no discomfort. Here, the first environmental temperature region is preferably a region having a width of 5 degrees or more. On the other hand, by changing the fan duty in the second environmental temperature region exceeding 30 ° C., the lifetime of the optical elements such as the illumination optical system α and the color separation / synthesis optical system β described above including the image modulation element is increased. Can do.

(Fan control method when usage environment changes)
Here, as a factor for changing the fan duty, a change from the normal environment (reference environment) of the use environment is also one factor. For example, the external atmospheric pressure can be cited as a factor for changing the fan duty.

  Therefore, when the usage environment is different from the normal environment (reference environment), as shown in FIG. 1 (b), the fan duty determined according to the environmental temperature is multiplied by the usage environment proportional constant B. It is desirable to use a drive fan duty. When the usage environment is a normal environment (reference environment), add the above-mentioned fan drive duty (the normal drive duty of each fan multiplied by the temperature proportionality constant A of each fan multiplied by the difference ΔT between the detected temperature and the threshold value) Used). As with the temperature proportional constant A, the usage environment proportional constant B has a given value for each fan.

  FIG. 1A shows changes in the fan duty with respect to changes in the environmental temperature in the fan control method. In FIG. 1 (a), the solid line is the normally driven fan duty. The threshold of the fan duty variable range and the fan duty invariable range is 30 ° C., the fan is driven with a constant fan duty below 30 ° C., and the fan duty increases in proportion to the environmental temperature above 30 ° C. I understand. When the usage environment changes (when the installation altitude of the device is higher than the reference altitude, such as at high altitudes), the normal drive fan duty is set to a constant multiple (greater than 1) as indicated by a broken line.

  The above is the case where the installation altitude of the apparatus is different from the reference altitude. However, when the installation attitude of the apparatus is different from the reference attitude, it is preferable to increase the rotation speed of the fan from the rotation speed in the reference attitude. Further, when the power supply voltage of the device is different from the reference power supply voltage, it is preferable to increase the rotational speed of the fan from the rotational speed at the reference power supply voltage.

  With the fan drive control method as described above, the noise level is kept constant in a room temperature environment where the user is close to the projector, and the fan output is changed in a high temperature environment where the user is far from the projector. The lifetime of the element can be increased.

(Modification)
As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various deformation | transformation is possible within the range of identity.

(Modification 1)
In the above-described embodiment, the second environmental temperature region is a higher temperature region than the first environmental temperature region, and in the second mode, the number of rotations of the fan is increased as the temperature rises. It is not limited to this. For example, in the second mode, the rotational speed of the fan may be increased compared to the first mode, and the rotational speed of the fan may be made constant in the second environmental temperature region.

(Modification 2)
In the above-described embodiment, the second environmental temperature region is higher than the first environmental temperature region. However, the second environmental temperature region is lower than the first environmental temperature region, and the second mode is set. Then, you may make it reduce the rotation speed of a fan with respect to a 1st mode. In this case, in the second mode, it is preferable to decrease the rotational speed of the fan in accordance with the temperature decrease.

(Modification 3)
The heat generating part in the apparatus is at least one of the above-described image modulation element, the optical element constituting the first optical system, and the optical element constituting the second optical system, as well as the power source and printed circuit board in the apparatus. It may be at least one of the following.

(Modification 4)
In the embodiment described above, for example, a plurality of liquid crystal panels are provided as image modulation elements. However, the present invention is not limited to this, and one liquid crystal panel or one image modulation element other than the liquid crystal panel is provided. It may be.

2 ・ ・ Projection lens unit (projection optical system) 4 ・ ・ Lamp cooling fan 5 ・ ・ Illumination optical system cooling fan 6 ・ ・ Color separation / combination optical system cooling fan 22 ・ ・ Control device, α ・ ・ Illumination optics System, β ・ ・ Color separation / synthesis optical system

Claims (14)

An image modulation element;
An illumination optical system for illuminating the image modulation element;
A projection optical system that projects the light modulated by the image modulation element onto a projection surface;
A cooling fan,
Control means for controlling the rotational speed of the fan,
The control means controls the fan in a first mode in which the rotation speed of the fan is constant in a first environmental temperature region, and in a second environmental temperature region different from the first environmental temperature region. A projection-type display apparatus, wherein the fan is controlled in a second mode in which the rotational speed of the fan is changed from the rotational speed in the first mode. Having environmental temperature detection means for detecting the environmental temperature where the device is installed;
2. The projection display device according to claim 1, wherein the control unit executes either the first mode or the second mode based on a detection result of the environmental temperature detection unit.   The projection display device according to claim 1, wherein the first environmental temperature region is a region having a width of 5 degrees or more.   A plurality of the image modulation elements are provided, and the illumination optical system includes a first illumination optical system common to each of the image modulation elements, and color separation after the color separation after passing through the first illumination optical system. 4. The projection display device according to claim 1, further comprising: a second illumination optical system that illuminates each of the image modulation elements. 5. The second environmental temperature region is a higher temperature region than the first environmental temperature region,
5. The projection type display device according to claim 1, wherein in the second mode, the number of rotations of the fan is increased with respect to the first mode. 6.   The projection display device according to claim 5, wherein in the second mode, the number of rotations of the fan is increased according to a temperature rise. The second environmental temperature region is a lower temperature region than the first environmental temperature region,
5. The projection type display device according to claim 1, wherein, in the second mode, the rotational speed of the fan is decreased with respect to the first mode. 6.   The projection display device according to claim 7, wherein, in the second mode, the rotational speed of the fan is decreased according to a temperature decrease.   9. The projection display device according to claim 1, wherein when the installation altitude of the apparatus is higher than a reference altitude, the rotational speed of the fan is increased from the rotational speed at the reference altitude.   10. The projection display device according to claim 1, wherein when the installation posture of the device is different from the reference posture, the rotational speed of the fan is increased from the rotational speed in the reference posture.   11. The projection display device according to claim 1, wherein when the power supply voltage of the device is different from the reference power supply voltage, the rotational speed of the fan is increased from the rotational speed of the reference power supply voltage.   2. The cooling fan cools at least one of the image modulation element, the optical element constituting the first optical system, and the optical element constituting the second optical system. 12. The projection display device according to any one of items 11 to 11.   12. The projection display device according to claim 1, wherein the cooling fan cools at least one of a power source and a printed circuit board in the device.   The projection display device according to claim 1, wherein the cooling fan cools a light source for illuminating the image modulation element.