JP3946120B2 - LCD projector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal projector.
[0002]
[Prior art]
The liquid crystal projector is equipped with a light source lamp, but the light source lamp has characteristics that when the lamp is lit at a high temperature, the lamp lighting performance is deteriorated and the life of the lamp is adversely affected. Yes.
[0003]
Therefore, when the light source lamp is extinguished, a cooling operation is performed such that the cooling fan is driven for a certain period of time, and after that, a transition is made to a standby state where lamp relighting can be accepted.
[0004]
However, when the AC input voltage is supplied again immediately after the AC input voltage supply is forcibly cut off in the lamp lighting state or the cooling operation state (hereinafter referred to as the cooling state). In this case, since the lamp lighting operation is performed, the light source lamp may be turned on again without being sufficiently cooled.
[0005]
When the AC input voltage is forcibly cut off, the AC power switch is turned off when the AC plug of the liquid crystal projector is removed from the AC outlet, or when the AC power switch is provided in the liquid crystal projector. There is a case.
[0006]
[Problems to be solved by the invention]
In the present invention, when the supply of the AC input voltage is forcibly cut off in the lamp lighting state or the cooling state, and the AC input voltage is supplied again immediately thereafter, the light source lamp is turned on with the lamp temperature being high. It is an object of the present invention to provide a liquid crystal projector capable of preventing the above.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a temperature sensor for detecting the ambient temperature of the light source lamp, and whether or not the detected temperature of the temperature sensor is below an allowable value when a lamp lighting command is input in the standby state. A means for determining, a means for turning on the light source lamp when the detected temperature of the temperature sensor is below the allowable value, and a light source lamp by driving the cooling fan for a certain period when the detected temperature of the temperature sensor exceeds the allowable value It is characterized in that it is provided with means for making it stand-by after performing a cooling operation such as cooling.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0009]
FIG. 1 shows the configuration of a light source lamp and a cooling fan control circuit of a liquid crystal projector.
[0010]
An operation signal from an operation unit 2 (an operation unit provided on the remote control or the liquid crystal projector main body) 2 is input to the CPU 1. Connected to the CPU 1 is a temperature sensor 3 provided in the liquid crystal projector main body and for detecting the ambient temperature of the light source lamp 5. Connected to the CPU 1 are a lighting circuit (lamp lighting circuit) 4 for the light source lamp 5 and a driving circuit (fan driving circuit) 6 for the cooling fan 7. The CPU 1 is also connected to a main power circuit 8 for supplying power to the lamp lighting circuit 4 and the fan drive circuit 6.
[0011]
FIG. 2 shows the operation of the CPU 1.
[0012]
When the power supply to the CPU 1 is turned on, that is, when the supply of the AC input voltage is started (step 1), the power is supplied to the CPU 1, but other circuits (for inputting the operation signal to the CPU 1) (Excluding the circuit) is in a standby state where no power is supplied (step 2).
[0013]
When a lamp lighting command is input from the operation unit 2 in the standby state (step 3), it is determined whether or not the temperature detected by the temperature sensor 3 (lamp ambient temperature) is equal to or lower than a predetermined allowable value (step 3). 4).
[0014]
When the detected temperature is less than the allowable value, the lamp is turned on (step 5). In the lamp lighting state, the light source lamp 5 is turned on and power is supplied to all circuits. Further, the cooling fan 7 is driven according to the temperature detected by the temperature sensor 3 or another temperature sensor (not shown).
[0015]
When a lamp turn-off command is input from the operation unit 2 in the lamp lighting state (step 6), the light source lamp 5 is turned off and the cooling fan 7 is driven for a certain period of time (step 7). . When the cooling state is finished and the cooling fan 7 is stopped, the standby state of Step 2 is restored.
[0016]
If it is determined in step 4 that the temperature detected by the temperature sensor 3 exceeds the allowable value, the cooling fan 7 is driven for a certain period of time (step 8). When the cooling state is finished and the cooling fan 7 is stopped, the standby state of Step 2 is restored.
[0017]
When the supply of the AC input voltage is forcibly cut off in the lamp lighting state of step 5 or the cooling state of step 7, and the AC input voltage is supplied again immediately thereafter, the temperature of the light source lamp 5 is an allowable value. The light source lamp 5 is not lit even if a lamp lighting command is input at such a time.
[0018]
That is, when the supply of the AC input voltage is forcibly cut off in the lamp lighting state or the cooling state, and the AC input voltage is supplied again immediately thereafter, the process proceeds from step 1 to step 2 to enter the standby state. In this state, when a lamp lighting command is input from the operation unit 2, the process proceeds from step 3 to step 4, and it is determined whether or not the temperature detected by the temperature sensor 3 is equal to or less than an allowable value. At this time, if the ambient temperature of the light source lamp 5 is higher than the allowable value, the light source lamp 5 is not turned on, and the process proceeds to step 8 to enter a cooling state. That is, the light source lamp 5 is cooled.
[0019]
The allowable value is preferably set so that it can be changed depending on the characteristics of the light source lamp used, the state (size, installation environment) of the liquid crystal projector, and the like.
[0020]
【The invention's effect】
According to the present invention, when the supply of the AC input voltage is forcibly cut off in the lamp lighting state or the cooling state, and the AC input voltage is supplied again immediately thereafter, the light source lamp is turned on with the lamp temperature being high. Can be prevented.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a control circuit for a light source lamp and a cooling fan of a liquid crystal projector.
FIG. 2 is a flowchart showing the operation of the CPU 1;
[Explanation of symbols]
1 CPU
2 Operation section 3 Temperature sensor 4 Lamp lighting circuit 5 Light source lamp 6 Fan drive circuit 7 Cooling fan 8 Main power supply circuit

Claims (1)

A temperature sensor for detecting the ambient temperature of the light source lamp,
Means for determining whether or not the temperature detected by the temperature sensor is less than or equal to an allowable value when a lamp lighting command is input in a standby state;
Means for turning on the light source lamp when the temperature sensor detected temperature is below the allowable value, and cooling the light source lamp by driving the cooling fan for a certain period when the temperature sensor detected temperature exceeds the allowable value Means to put into standby after cooling operation,
LCD projector equipped with.

Images