JP2002258406A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device which has a housing internal temperature detecting means and a lamp power control means and controls lamp power according to the temperature information obtained by the temperature detecting means and then protects a housing. SOLUTION: The electric power of a lamp 3 as a heat source is adjusted by controlling the lamp power control part 2 according to the temperature information from the temperature detecting means 1 to suppress the rise of the temperature in the housing, thereby protecting the housing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device such as a liquid crystal projector, and more particularly to a power control method.

[0002]

2. Description of the Related Art In a conventional projection display device, when the temperature inside a housing rises due to factors such as heat generation of a lamp and rise in outside air temperature, a method shown in FIG. 6 is used as a method for suppressing the rise in temperature. . That is, by controlling the fan speed control means 4 based on the temperature information from the temperature detection means 1, the supply / exhaust amount of the cooling fan 5 is adjusted to suppress a rise in the temperature inside the housing, thereby protecting the housing. It is.

[0003]

However, in this conventional method, the fan speed is increased as the temperature inside the housing increases, and a problem arises that fan noise increases. The projection display device is often used in a relatively quiet place such as a meeting or watching a movie. For these uses, it is desired that the fan noise be as quiet as possible.

An object of the present invention is to control a lamp power as a heat source without performing a fan speed control which causes an increase in fan noise when a temperature in a housing rises. Accordingly, an object of the present invention is to provide a projection display device that suppresses a rise in temperature inside a housing.

[0005]

According to another aspect of the present invention, there is provided a projection display apparatus including a temperature detecting means in a housing and a lamp power control means, wherein temperature information obtained from the temperature detecting means is provided. To provide a method of controlling the lamp power according to

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION
Temperature detecting means for detecting the temperature in the housing, and lamp power controlling means for controlling the power of the lamp as a light source, wherein the lamp power controlling means A projection display device characterized by controlling electric power, and has an effect of preventing a rise in temperature inside a housing and increasing protection of the housing without increasing fan noise.

Next, the invention according to claim 2 of the present invention is:
Temperature detecting means for detecting the temperature in the housing, and lamp power switching means for switching the power of the lamp as a light source in a stepwise manner, wherein the lamp power switching means switches the detected temperature when lowering the power. A projection display device characterized in that the temperature is set to be higher than the detected temperature at the time of switching to increase power, and has an effect of preventing frequent lamp power switching and suppressing flickering of image brightness.

Further, the invention according to claim 3 of the present invention provides:
When the temperature information obtained from the temperature detecting means after the lamp is turned on is between the detected temperature when the lamp power switching means switches to lower the power and the detected temperature when the power is switched to increase the power. 3. The projection display device according to claim 2, wherein the lamp power control is switched to the high power control side once, and the lamp power control is easily shifted to the high power control side.
This has the effect of displaying an image in a brighter state.

(Embodiment) The first aspect of the present invention will be described below.
The embodiment of the invention described in (1) will be described with reference to FIG.

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention. In FIG. 1, 1 is a temperature detecting means, 2
Denotes lamp power control means, and 3 denotes a lamp.

In FIG. 1, by controlling a lamp power control means 2 on the basis of temperature information from a temperature detection means 1, the power of a lamp 3 serving as a heat source is adjusted to suppress a rise in temperature inside the housing, and Protect your body.

As an example of the embodiment of the present invention, a case where the lamp power is switched stepwise according to the temperature information from the temperature detecting means 1 will be described as an example.

FIG. 2 is a diagram showing the relationship between the temperature inside the housing and the lamp power according to the first embodiment of the present invention. As the temperature in the housing increases, the lamp power is reduced to W as shown in FIG.
1, W2 and W3 are gradually reduced. By reducing the lamp power serving as a heat source in this manner, an increase in the temperature inside the housing can be suppressed.

According to the present embodiment, it is possible to prevent the temperature inside the housing from rising and to protect the housing without increasing the fan noise.

Here, consider the case where the temperature in the housing is near the power switching temperature T1 or T2 in FIG. For example, when the temperature in the housing is near T1, the control shown in FIG. 3 is repeated. That is, when the temperature becomes slightly higher than T1, the lamp power is reduced from W1 to W2. As a result, the calorific value of the lamp decreases, the temperature in the housing falls below T1, and the lamp power is increased again from W2 to W1. Then, the calorific value of the lamp increases again, and the temperature inside the housing becomes higher than T1. As described above, in the method shown in FIG. 2 in which the lamp power is switched stepwise in response to the rise in the temperature inside the housing, when the temperature inside the housing is near the lamp power switching temperature, the lamp power switching is frequently repeated, and as a result, The problem that the brightness of the image flickers occurs.

FIG. 4 is a diagram showing the relationship between the temperature inside the housing and the lamp power according to the second embodiment of the present invention. As can be seen from a comparison with FIG. 2, the temperature in the case when switching is performed so as to reduce the power is set higher than the temperature in the case when switching is performed to increase the power. Thus, for example, once the temperature in the housing rises above T1, T
Until the lamp power becomes lower than 3, the lamp power is maintained in the state of W2, and as a result, it is possible to suppress the brightness of the image from flickering.

In the method shown in FIG. 4, if the temperature inside the housing is lower than T1 when the lamp is turned on, the lamp power is controlled at the maximum power W1, so that an image can be displayed in the brightest state. However, once the lamp is turned off in this state, generally even if the cooling fan continues to rotate for a while and continues to cool the inside of the housing, when the fan stops thereafter, the residual heat of the lamp stays in the housing, There is a case where the temperature in the case becomes higher than T1. When the lamp is turned on again in this state, the lamp power is controlled by W2. Even if the rotation of the cooling fan resumes, the heat trapped in the housing is gradually discharged, and even if the temperature in the housing drops to T4 (T3 <T4 <T1) and stabilizes, the lamp power remains at W2, It does not switch to W1. That is, if the temperature inside the housing is high due to the heat stored inside the housing when the lamp is turned on, an image may not be displayed in a bright state in some cases.

FIG. 5 is a diagram showing the relationship between the temperature in the housing and the lamp power according to the third embodiment of the present invention. In this method, after the lamp is turned on, when the time for discharging the heat trapped in the housing elapses, the temperature in the housing is switched between a temperature at which the lamp power is switched to lower and a power at which the power is increased. This is a method of switching to the high power side only once when the temperature of the hour is reached. The time during which the heat trapped in the housing is exhausted may be set to, for example, a time experimentally obtained. As a result, if the temperature inside the housing at the time when the heat trapped in the housing is discharged is, for example, T4 (where T3 <T4 <T1), the lamp power is switched from W2 to W1, and the lamp power is changed to the brightest state. Images can be displayed. That is, the lamp power control can be easily shifted to the high power control side, and the image can be displayed in a brighter state.

[0019]

As described above, according to the projection display device of the present invention, the temperature of the projection display device can be increased without increasing fan noise by detecting the temperature and controlling the power of the lamp. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the temperature in the housing and the lamp power according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a temperature T in the housing according to the first embodiment of the present invention.
Flow chart of lamp power control near 1

FIG. 4 is a diagram showing a relationship between a temperature in a housing and lamp power according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a temperature in a housing and lamp power according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Temperature detection means 2 Lamp power control means 3 Lamp 4 Fan speed control means 5 Fan

Claims (3)

[Claims] A temperature detecting means for detecting a temperature inside the housing; and a lamp power controlling means for controlling power of a lamp as a light source, wherein the lamp power is controlled in accordance with temperature information obtained from the temperature detecting means. A projection display device, wherein the control means controls the power of the lamp. A temperature detecting means for detecting a temperature inside the housing; and a lamp power switching means for switching power of a lamp as a light source in a stepwise manner. The lamp power switching means performs switching so as to reduce the power. Wherein the detected temperature at the time is set higher than the detected temperature at the time of switching to increase the power. 3. After the lamp is turned on, the temperature information obtained from the temperature detecting means includes a detected temperature when the lamp power switching means performs switching so as to reduce power and a detected temperature when performing switching to increase power. 3. The projection type display device according to claim 2, wherein when the power supply is changed, the power is once switched to the high power side.