JP3177362B2 - Projection display device - Google Patents

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 which displays a video signal using, for example, a liquid crystal display panel and a light source lamp.

[0002]

2. Description of the Related Art FIG. 4 is a diagram showing a conventional circuit block. The input video signal is converted by the video signal processing circuit 1 into a displayable video signal. This video signal is LC
In order to drive a D (Liquid Crystal Device) panel 3, the LCD drive circuit 2 changes to a video drive signal. The obtained video drive signal drives the LCD panel 3, and the light from the light source 5 causes the image to be displayed on the screen 4.
It is projected on. The voltage supply circuit 6 supplies voltages to various circuits such as the video signal processing circuit 1 and the LCD drive circuit 2, and supplies the light source 5 with a high voltage for driving the light source when the power is turned on and a voltage during normal use.

The control circuit 7 controls the voltage supply circuit 6 and controls whether to output a voltage from the voltage supply circuit 6. Then, the lighting detection circuit 8 detects whether or not the light source 5 is turned on by the voltage supply circuit 6. If the detection circuit 8 determines that the light source 5 is not lit, the control circuit 7 outputs a control signal to the voltage supply circuit 6 to stop the voltage supply. When detecting that the light is turned on, the control circuit 7 outputs a control signal for setting the video signal to a predetermined level (for example, a black level) to the video mute circuit 9 for a certain period from the time of lighting, and the video mute circuit 9 The video signal processing circuit 1 mutes the video signal.

Further, the display generation circuit 10 receives the lit information from the control circuit 7 and outputs the character signal in order to make a description to mute the video signal on the screen.

[0005] For example, a character for performing a wait display such as "Please wait for a while" or a timer display such as a remaining mute time indicating how long the video mute is released is generated. Superimposed on the signal. Here, the video signal is set to a predetermined level by the video mute circuit 9, and a character signal is superimposed on the video signal.

The operation unit 12 is a part for inputting all operations of the viewer and the user, and is an input means such as a remote control device (remote controller) and a keyboard.

Circuits such as a control circuit 7, a lighting detection circuit 8, a mute circuit 9, and a display generation circuit 10 are provided in a CPU indicated by a dashed line, and a voltage is constantly applied from a power supply.

Next, the operation will be described with reference to FIG. FIG. 5 is a time chart showing the power on / off state. FIG. 5a shows the power on / off, FIG.
Indicates ON / OFF of the light source, and FIG. 9C indicates whether or not there is an output from the LCD panel.

For convenience, the light source is shown as being capable of being turned on at the same time that the power is turned on. However, in practice, the light source is turned on with a certain time lag. The time lag depends on the type of gas sealed inside the light source and its mixing ratio,
Alternatively, it changes due to various factors such as the excited state and temperature of the gas and the temperature of the outside air, and is shown here without taking this into consideration.

First, at time T11, the operation unit 12 is operated, and the control circuit 7 outputs a control signal to supply power to the voltage supply circuit 6. The voltage supply circuit 6 supplies a voltage to various signal processing circuits such as the video signal processing circuit 1 and the LCD drive circuit 2 and applies a high voltage capable of driving the light source 5 to the light source.

Then, the gas in the light source is excited and becomes active. However, it cannot be driven immediately due to the characteristics of the LCD panel.
Color unevenness will occur on the top. The cause of the color unevenness is that, due to the structure of the liquid crystal panel, the liquid crystal is sandwiched by a substrate such as glass, and the liquid crystal becomes uneven when the liquid crystal is sandwiched. It is conceivable that the liquid crystal is deviated because the surface is not uniform. In addition, the color unevenness of the liquid crystal panel R
Of (red) G (green) and B (blue), green is most likely to occur.

Therefore, after the lighting of the light source 5 is detected, L
The video signal is muted for a time Ta until the CD panel is stabilized. This is because the control circuit 7 that has detected the lighting outputs the mute signal from the mute generation circuit 9 for the time Ta, and switches the video signal to a predetermined level. As a result, the video signal processing circuit 1 operates at time T11.
The video signal is made valid with a delay of the time Ta.

Next, at time T12, after the power is cut off by the operation unit 12, the time t
The case where the power is supplied (turned on again) at time T13 after elapse of b will be described. Since this time tb is shorter than the time Tx during which the light source 5 can be cooled and turned on again, the light source 5 cannot be turned on at time T13. Therefore, non-lighting is detected by the light-on detection circuit 8, and a control signal for stopping the voltage supply circuit 6 is output from the control circuit 7 by the non-lighting detection signal. Therefore, the voltage supply is cut off at time T14. The period between times T14 and T13 is the time required for detection, and the shorter the time, the more effective.

Then, unless there is a request from the viewer or the operator and the operation of the operation unit 12 is not performed, the re-lighting is not performed. At the time T15, when the relighting operation is performed, the power supply is started, the power is sufficiently cooled during the power-on time, and the time exceeds the relightable time Tx, so that the light source 5 relights. The video signal is muted during the liquid crystal drive time Ta from the re-lighting, and the video signal becomes valid after the lapse of the time Ta.

Also, when the voltage supply is cut off at time T16 and then cooled sufficiently and the voltage is supplied at time T17, the light source 5 is similarly turned on again, and the light source 5 is again turned on for a time Ta after the relighting.
After that, the video signal becomes valid.

Here, the time Ta varies depending on the liquid crystal panel, and is not a fixed time.
The time (sec) and the time Tx also vary, but are 60
The time of (sec) is normal.

When the image mute is performed in these states, the display generation circuit 10 displays a wait display such as "Please wait for a while" or the remaining time until the mute is released (for example, "15 seconds"). Is displayed. This residue is reduced as needed and is displayed sequentially.

Thus, it is possible to prevent the display of an unnecessary image to the viewer without displaying the color unevenness of the LCD panel when the power is turned on.

[0019]

However, the accuracy of the lamp, which is a light source, has been improved, and it has become possible to relight the lamp again without a long cooling period. In addition, the LCD panel does not become non-active instantaneously even when the power is turned off, but remains in a state where it can be immediately activated for a while.

Nevertheless, in the above-mentioned conventional example, a certain time was required until re-input.

[0021]

According to the present invention, there is provided a signal processing means for converting an input video signal into a signal from a liquid crystal panel means, a light source means for projecting a signal from the liquid crystal panel means to a display means, The video signal is set to a predetermined level, a video control unit for invalidating the video signal, a voltage supply unit for supplying a voltage to each of the units, and a lighting detection unit for detecting lighting of the light source. In a projection display device that invalidates a video signal for a set time from the time of lighting, a time counting unit that counts the non-lighting time of the light source, based on the counted time of the time counting unit,
An object of the present invention is to provide a projection display apparatus characterized by setting an invalid time of the video control means.

Further, according to the present invention, there is provided a signal processing means for converting an input video signal into a signal from a liquid crystal panel means, a light source means for projecting a signal from the liquid crystal panel means to a display means, A video control means for setting a level and invalidating a video signal, a voltage supply means for supplying a voltage to each of the means, a display signal generating means for superimposing a character or the like on the video signal, and detecting lighting of the light source And a time counting means for counting the non-lighting time of the light source, wherein the time counting means counts the non-lighting time of the light source. Based on the time counted by the means, the invalid time of the video control means is set, and the display time or display content of the output character signal of the display generating means is changed. There is provided a projection display device.

Further, according to the present invention, there is provided a signal processing means for converting an input video signal into a signal from a liquid crystal panel means, a light source means for projecting the signal from the liquid crystal panel means to a display means, Level, and a video control unit for invalidating a video signal; a voltage supply unit for supplying a voltage to each unit; and a lighting detection unit for detecting lighting of the light source. In a projection type display device for invalidating a video signal for a given time, a time counting means for counting a non-lighting time of the light source, and an invalid time of the video control means based on the counted time of the time counting means. When the counting time exceeds at least the driving time from when the liquid crystal panel is turned on to the time when the liquid crystal panel can normally project a video signal, the counting time is referred to as the driving time. There is provided a projection display device characterized by comprising a dead time setting means for properly.

[0024]

According to the present invention, a non-lighting time of a light source is detected, and a video mute period at the time of relighting is set based on the detection.

[0025]

FIG. 1 is a block diagram showing an embodiment of the present invention.
The same reference numerals as in the conventional example are assigned the same reference numerals and explanations are omitted.

Reference numeral 13 denotes a timer circuit of counting means, which inputs the data of the non-lighting time obtained by the control circuit 7 from the signal from the light-on detection circuit 8 and counts the non-lighting time. This is included in the CPU.

FIG. 2 is a time chart showing the power on / off state of the embodiment of the present invention. These FIGS. 1 and 2
The operation will be described with reference to FIG.

First, at time T1, the operation unit 12 is operated, and the control circuit 7 outputs a control signal to the power supply circuit 6 to supply power. The voltage supply circuit 6 supplies a voltage to various signal processing circuits such as the video signal processing circuit 1 and the LCD drive circuit 2 and applies a high voltage capable of driving the light source 5 to the light source.

At this time, the light source 5 'is turned on at time T as shown in FIG.
Lights up at 1. Here, the time required for turning on the light source is omitted. The video signal is muted for the time Ta from the detection of the lighting of the light source 5 'to the stabilization of the LCD panel as shown in FIG. 2c. This is because the control circuit 7 that has detected the lighting outputs the mute signal from the mute generation circuit 9 for the time Ta, and switches the video signal to a predetermined level. As a result, the video signal processing circuit 1 validates the video signal with a delay of the time Ta from the time T1. This is to prevent color unevenness.

Next, at time T2, after the power is cut off by the operation unit 12, the time tb
A case in which power is supplied (turned on again) at time T3 after the lapse has been described. Since the light-emitting time Tx 'of the light source 5' is extremely shorter than the conventional light-emitting time Tx of the light source 5, re-lighting can be performed at time T3 when the time tb has elapsed.
Therefore, the non-lighting is detected by the lighting detection circuit 8 as in the conventional example, and a control signal for stopping the voltage supply circuit 6 is output from the control circuit 7 by the non-lighting detection signal,
The voltage supply is not interrupted.

The time tb is shorter than the time Ta required for the LCD panel 3 to stabilize.
Reduces the video mute period from the time Ta to the time tb. Thereby, the time until the video is displayed can be reduced. This time is a count signal output from the control circuit 7 to the timer circuit 13 in response to a signal from the lighting detection circuit 8 and counted by the timer circuit 13, and time data is output to the control circuit 7 as needed.

Next, when the voltage supply is cut off at time T4 and then cooled sufficiently and the voltage is supplied at time T5, the light source 5 'is similarly turned on again, and after a time Ta from the re-lighting, The video signal becomes valid. This is because the time tc from power-off to re-lighting is longer than the time Ta.

When the time tc has elapsed, the LCD panel 3
Becomes non-active, and the LCD panel 3 is activated after the power is turned on again at time T5. Therefore, the video mute time is set so that the video signal is unmuted after the time Ta.

That is, if the power-off time exceeds the stabilization time Ta of the LCD panel 3, the video mute time is reduced to the time Ta.
By doing so, video mute is not performed unnecessarily.

Thus, it is possible to prevent the display of an unnecessary image to the viewer without displaying the color unevenness of the LCD panel when the power is turned on. In addition, the video mute time can be varied according to the power-off time, and the video mute can be performed in a minimum time.

Next, specific control will be described with reference to the flowchart of FIG.

First, this flowchart is started in step 101 of FIG. At that time, Tm indicating the mute time
Is reset (to Tm = Ta). In step 102, power on / off is confirmed. This corresponds to the control circuit 7
By confirming the state of the voltage supply circuit 6 by
Can be determined. Even in other cases, the control circuit 7 may provide a power on / off flag and confirm the flag. In order to explain step by step, it is assumed here that the power-on operation is performed when the power is turned off, and that step 10 is performed.
Go to 3.

In step 103, it is confirmed whether or not the light source (lamp) 5 'is turned on. If it is lit, the process returns to step 102. If not, the process proceeds to step 104 to perform a lighting operation. In step 104, a signal indicating that the power-on operation has been performed is output from the control circuit 7 to the voltage supply circuit 6. Then, the power supply circuit operates to supply a voltage to each circuit (step 105), and applies a high voltage to the light source 5 'for several seconds to drive the light source 5' (step 106).

Then, in step 107, it is determined whether or not the light source 5 'is turned on. Normally, the light source 5 ′ is turned on by the application of the high voltage in step 106, but if lighting is not performed for some reason, the non-lighting is detected by the lighting detection circuit 8 (step 110), and the control circuit 7 A signal to stop supplying voltage is output to the supply circuit 6 (step 111).

When the light source 5 'is turned on, processing is performed in a video mute processing loop shown in FIG. Then, a normal voltage is supplied to each circuit to reproduce a video signal (step 109).

This video mute processing loop is performed according to the flowchart in FIG. First, a mute process is started (step 201), and a video mute process is performed. In this video mute processing, the video mute time Tm is determined from the control circuit 7 to the mute processing circuit 9 based on the non-lighting detection time from the lighting detection circuit 8. This time Tm corresponds to steps 112 to 1 of a flowchart described later.
14 is set.

When the power is first turned on, the time Tm is set to Ta.
And video mute processing is performed until the time Tm becomes zero. That is, the mute is performed for the time Tm. When the mute process is performed for the time Tm, the mute process ends, and the process proceeds to step 109. And step 10
9 is performed.

Thereafter, the process returns to step 102, and the same flowchart of steps 102-103-102-103-102-.

Therefore, when the power-off operation is performed, it is determined in step 102 that the power is off, and the mute time Tm is increased in step 112. After the power is turned on, the time Tm becomes zero due to the operation of the mute process, and the time Tm is increased from zero (step 11).
2). In step 113, the time Tm is compared with the time Ta required for stabilizing the LCD panel. In this comparison, if the time Tm is shorter, the process returns to step 102. If the time Tm is longer, the fixed value of the time Ta is substituted for the time Tm in a step 114, and
Return to. Steps 102-112-113 (-114) -102- are performed until the power-on operation is performed.
.. Are repeatedly operated.

Thus, the mute time Tm increases while the power is off, and the stabilization time Ta of the LCD panel 3 is increased.
Is exceeded, the time Tm becomes the same as the time Ta, so that the mute time Tm can be set according to the time from power-off to power-on.

Next, in the mute processing which is performed when the power is turned on and steps 102 to 103 to 109 are executed, the video signal is muted only during the mute time created in this loop.

Therefore, as shown in FIG. 2, the mute time can be changed according to the length of the power-off period (tb, tc).

As another embodiment, there is a method of reflecting a mute time on a display character as follows. In this method, the time data of the video mute time is received from the timer circuit 13 by the control circuit 7 and is output to the display generation circuit 10 so that the mute time is changed to display characters and superimposed on the video signal.

For example, in FIG.
Seconds, time tb is 20 seconds, and time tc is 40 seconds,
At time T3, 20 seconds of the time data is output from the timer circuit 13 to the control circuit 7, and the display generation circuit 10 creates a character signal such as "20 seconds remaining" accompanying the time data. Then, the character signal is superimposed on the video signal muted by the superimposing circuit 11. As a result, "20 seconds" can be displayed on the background of the predetermined level.

At time T1 and time T5, the time data is output from the timer circuit 13 to the control circuit 7, and the display generation circuit 10 creates a character signal such as "30 seconds remaining" in each case. Then, similarly, it is superimposed on the video signal, so that "30 seconds" can be displayed on the background of the predetermined level.

Then, the countdown is performed every second. When the display becomes "0 second", the video mute is released, and the display of the character signal "0 second" is released, and the video signal is released. Can be displayed.

Note that "+1" used in this flowchart is used.
Needless to say, 1 of “−1” does not have to be 1, and should be changed each time depending on the time taken for the loop in this flowchart. Further, since the mute time Tm is used as time data, it is better to treat the mute time Tm as data in units of seconds.

[0053]

According to the present invention, since the video mute time is set according to the length of the power-off period, even when the voltage is cut off,
When the LCD panel is ready to be activated immediately, the video mute period can be shortened, and the video can be viewed in a short time.

In addition, since the time until the video signal is displayed (ie, the time until the video mute is released) is displayed, the viewer can easily grasp the standby time.

[Brief description of the drawings]

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

FIG. 2 is a timing chart of an embodiment of the present invention.

FIG. 3 is a flowchart of an embodiment of the present invention.

FIG. 4 is a circuit block diagram of a conventional example.

FIG. 5 is a timing chart of a conventional example.

FIG. 6 is a diagram showing color unevenness of an LCD panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image processing circuit 2 LCD drive circuit 3 LCD panel 4 Screen 5 'Light source 6 Voltage supply circuit 7 Control circuit 8 Lighting detection circuit 9 Image mute circuit 10 Display generation circuit 11 Superposition circuit 12 Operation part 13 Timer circuit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/133 G09G 3/36

Claims (3)

(57) [Claims] 1. A signal processing means for converting an input video signal into a signal from a liquid crystal panel means, a light source means for projecting a signal from the liquid crystal panel means on a display means, and setting the video signal to a predetermined level. Image control means for invalidating a video signal, voltage supply means for supplying a voltage to each of the means,
In the projection display device, comprising lighting detection means for detecting lighting of the light source, and invalidating a video signal for a set time from the lighting of the light source, a time counting means for counting the non-lighting time of the light source, A projection-type display device, comprising setting an invalid time of the video control means based on the time counted by the time counting means. 2. A signal processing means for converting an input video signal into a signal from a liquid crystal panel means, a light source means for projecting a signal from the liquid crystal panel means on a display means, and setting the video signal to a predetermined level. Image control means for invalidating a video signal, voltage supply means for supplying a voltage to each of the means,
Display signal generating means for superimposing a character or the like on the video signal,
In the projection display device, comprising lighting detection means for detecting lighting of the light source, and invalidating a video signal for a set time from the lighting of the light source, a time counting means for counting the non-lighting time of the light source, And setting the invalid time of the video control means based on the time counted by the time counting means and changing the display time or display content of the output character signal of the display generating means. Type display device. 3. A signal processing means for converting an input video signal into a signal from a liquid crystal panel means, a light source means for projecting a signal from the liquid crystal panel means on a display means, and setting the video signal to a predetermined level. Image control means for invalidating a video signal, voltage supply means for supplying a voltage to each of the means,
In the projection display device, comprising lighting detection means for detecting lighting of the light source, and invalidating a video signal for a set time from the lighting of the light source, a time counting means for counting the non-lighting time of the light source, Based on the time counted by the time counting means, the invalid time of the picture control means is set, and at least the driving time from when the liquid crystal panel is turned on until the picture signal can be normally projected is counted. A projection display device comprising: an invalid time setting means for setting the counting time to be equal to the driving time when the time has elapsed.