JP2000112027A - Projection type picture display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture display device with a simple constitution by which the display of a bright picture is restarted even right after the completion of picture display. SOLUTION: A rear projection type television 1 constituted as a device using a metal halide lamp 81 as a light source is provided with a turning-on circuit 61 which uses the ignition voltage of two levels, high and low. It is turned on by low ignition voltage applied to when the temperature of the lamp 81 is low, and is turned on by high ignition voltage applied to when the temperature of the lamp 81 is high. Thus, the lamp 81 is surely turned on even when the temperature of it is high right after turning off, and also the restarting of the picture display is made possible even right after the completion of the picture display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a projection type image display device, and more particularly to a projection type image display device using an arc discharge lamp as a light source for image projection.

[0002]

2. Description of the Related Art There is a projection type image display apparatus which modulates light according to an image and projects the modulated light onto a screen to display an image. Such a projection type image display device is used to present an image to many people at once, and in recent years,
It is also being used for relatively large-screen televisions. As a light source for image projection, a light source having a large amount of light emission is preferable in order to display a bright image, and an arc discharge lamp represented by a metal halide lamp is generally used.

In an arc discharge lamp, it is necessary to ionize a sealed gas in order to shift from a turned-off state to a turned-on state. For this reason, a projection type image display device applies a predetermined ignition voltage to the lamp for about one second. I do.
The lit lamp generates heat and becomes high in temperature, but cools down gradually after returning to the room temperature. Next, when an image is displayed, the projection type image display device applies the ignition voltage again to turn on the lamp.

However, in an arc discharge lamp, the difficulty of ionization of a gas changes depending on the temperature. Therefore, the ignition voltage required to start lighting differs depending on whether the lamp is at a low temperature or a high temperature. For example, in the case of a standard metal halide lamp, the lamp is lit by applying a voltage of 5 to 20 kV at a low temperature, but cannot be lit at a high temperature unless a voltage of 20 to 45 kV is applied.

Therefore, immediately after the display of an image is completed, that is, immediately after the arc discharge lamp has been turned off, the lamp cannot be restarted and the display of the image cannot be resumed while the lamp is at a high temperature. is there. For example, in a projection-type image display device configured as a television, if the user accidentally touches a switch of the remote control device to terminate the display, the display cannot be resumed for a while, and during that time, the user cannot watch the television. Will not be able to.

Some proposals have been made as a countermeasure against this inconvenience. For example, Japanese Patent Application Laid-Open No. Hei 7-319068 has two metal halide lamps, and immediately turns off the other immediately after turning off one of them. A device that allows display to be resumed in a timely manner is disclosed. JP-A-2-690
No. 84 proposes a device having a delay function that does not turn off the lamp for a certain period of time even if the user performs a light-off operation. Japanese Utility Model Laid-Open Publication No. 4-33034 discloses a metal halide lamp and an auxiliary lamp such as a halogen lamp which can be turned on more quickly than this. When the display is restarted immediately after the metal halide lamp is turned off, the auxiliary lamp is used for a certain time. A lighting device is disclosed.

In the devices disclosed in these publications, the display can be resumed immediately after the lamp is turned off, and the inconvenience of making the user wait is eliminated.

[0008]

However, in a method in which two lamps are provided and one is turned on immediately after the other is turned off, it is necessary to always have two lamps that can be turned on. Sometimes it is not possible to quickly resume the image display. In the method of delaying turning off, it is impossible to relight immediately after turning off the light after the delay time has elapsed. Further, in a method including an auxiliary lamp that is quickly turned on, since the amount of light emitted from such an auxiliary lamp is small, only an image with insufficient brightness can be displayed for a certain period of time after the display is restarted.

The present invention has been made in view of the above problems, and has as its object to provide a projection-type image display device having a simple configuration capable of restarting display of a bright image immediately after the end of image display.

[0010]

According to the present invention, there is provided a projection type image display apparatus using an arc discharge lamp as a light source for image projection, wherein a lighting means for outputting a plurality of stages of ignition voltages is provided. The ignition voltage to be supplied to the arc discharge lamp is selected from a plurality of levels of ignition voltage according to the state of the arc discharge lamp.

The arc discharge lamp is turned on at any time by setting the lowest voltage value of the ignition voltage in a plurality of stages for lighting at room temperature and the highest voltage value for lighting at the temperature of the lamp immediately after turning off. Thus, the display of the image can be reliably restarted not only when a long time has elapsed since the end of the display but also immediately after the end of the display. Since the display of the image is restarted by re-lighting the same lamp, the configuration is not complicated, and the brightness of the image when the display is restarted is almost the same as the brightness of the normal image. If an intermediate voltage is set between the minimum and maximum voltages, even if the lamp has cooled to some extent after turning off the lamp, it is possible to apply an unnecessarily high voltage to damage the lamp electrodes. Image display can be resumed while minimizing it.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the projection type image display device of the present invention will be described with reference to the drawings. FIG.
FIG. 1 schematically shows the configuration of an image display of a projection type image display device (hereinafter, also simply referred to as a projection display device) 1 of the present embodiment. The projection display device 1 receives a television signal, modulates light from a light source with the RGB signals, projects the modulated light onto a screen from the back side, and displays a color image on the screen. It is configured as a television.

The projection display device 1 includes a screen 50 for displaying an image, a light source unit 2 for supplying light for image projection.
0, a modulation unit 30 for modulating light from the light source unit 20 with RGB signals, a projection unit 40 for enlarging the modulated light and projecting it on a screen 50 to form an image, and a housing 10 for accommodating all of them. The projection display device 1 uses a metal halide lamp 81, which is a type of arc discharge lamp, as a light source for image projection. The lamp 81 is replaceable and emits white light.

The light source section 20 is provided with two mounting sections 21 for mounting the lamps 81.
1 can be mounted simultaneously. However, instead of turning on the two mounted lamps 81 at the same time, only the lamp 81 mounted on the mounting portion 21 at the position indicated by the symbol A is turned on, and the mounting portion at the position indicated by the symbol B is turned on. The lamp mounted on 21 is not turned on. Position A
Is called a lighting position, and the position B is called a non-lighting position. Non-lighting position B
The lamp at is a spare lamp.

Between the lighting position A and the modulator 30, a polarization converter 28 for aligning the light of the lit lamp 81 to one of P-polarized light and S-polarized light is disposed. As a result, all the light from the light source unit 20 is converted into polarized light suitable for the liquid crystal panel of the modulation unit 30 described later, and is guided to the modulation unit 30.

An openable / closable door 11 is provided at a portion of the housing 10 facing the non-lighting position B at the lower front surface. By opening the door 11, the lamp can be removed from the mounting portion 21 at the non-lighting position B through the opening, and the lamp can be mounted on the mounting portion 21. FIG. 1 shows a state immediately before a spare lamp is mounted on the mounting portion 21 in the non-lighting position B, and the spare lamp is not shown. When the mounting portion 21 is in the lighting position A, the lamp 81 of the mounting portion 21 cannot be touched, and the lamp 81 cannot be replaced.

The two mounting portions 21 are movable so as to be alternately arranged at a lighting position A and a non-lighting position B. Specifically, the mounting section 21 is held by a holding section 22 having a rotating shaft 23, and the light source section 20 includes a holding section 22.
Is provided with a motor 24 for rotating. A gear 26 and a gear 27 that mesh with each other are fixed to the rotating shaft 23 of the holding unit 22 and the rotating shaft 25 of the motor 24, respectively. The rotation of the motor 24 causes the holding unit 22 to rotate and the mounting unit 21 to also rotate. . When one of the two mounting portions 21 is in the lighting position A, the other is in the non-lighting position B
, The lighting position A and the non-lighting position B and the two mounting portions 21 are arranged symmetrically with respect to the rotation axis 23.

Incidentally, three or more mounting portions 21 may be provided, and the non-lighting position B may be set to two or more, so that a plurality of spare lamps may be mounted. In that case, the door 11 may be formed so as to be large so as to face all the non-lighting positions B, or may be sized to face only one non-lighting position B. Even in a configuration including three or more mounting portions 21, the lighting position A and the non-lighting position B and the mounting portion 21 are arranged rotationally symmetrically with respect to the rotation shaft 23.

The modulating unit 30 separates the white light supplied from the light source unit 20 into light of three primary colors of R, G, and B, and modulates the separated three colors of light individually. The light of the colors is synthesized and guided to the projection unit 40. The modulation unit 30 includes
Three color filters 31, 32, 33 for decomposing the light from the light source unit 20, three transmissive liquid crystal panels (LCD) 36, 37, 38 for modulating the decomposed light,
A cross prism 39 for synthesizing the modulated light is provided.

The filters 31, 32, and 33 reflect R light and transmit other light, G light reflects and transmits other light, and B light reflects and transmits other light. What is transmitted. These filters 31, 32, 3
Numeral 3 is arranged on the optical path of light incident from the light source unit 20 at an angle of 45 ° with respect to the optical path, and reflects light in parallel in the same direction. The cross prism 39 is arranged at a position to directly receive the reflected light of the central filter 32.
On the sides of the cross prism 39, total reflection mirrors 34a and 34b for guiding the reflected lights of the filters 31 and 33 to the cross prism 39 are provided.

The LCDs 36, 37, and 38 are for modulating R light with an R signal among RGB signals, for modulating G light with a G signal, and for modulating B light with a B signal. , And arranged perpendicular to the reflected light from the mirror 34a, the filter 32, and the mirror 34b, respectively. Filter 3
1, 32, and 33 and the LCDs 36, 37, and 38 may be arranged so that light and signals correspond to each other, and there is no other restriction on the order of arrangement.

The cross prism 39 is a regular quadrangular prism formed by joining four prisms each being a right-angled isosceles triangular prism. The joining surface of each prism is a half mirror, and is inclined by 45 ° with respect to each of the three colors of incident light. The cross prism 39 transmits the light from the LCD 37, and
By reflecting the light from D36 and the light from LCD 38, the modulated three colors of light are combined and guided to the projection unit 40.

The distance between the filter 31 and the filter 32,
Distance between filter 32 and filter 33, filter 3
The distance between the mirror 1 and the mirror 34a and the distance between the filter 33 and the mirror 34b are all set to be equal.
The distance 36 and the distance between the mirror 34b and the LCD 38 are all set equal. Therefore, filter 31
The optical path length from the filter 31 to the LCD 36 via the mirror 34a is equal to the optical path length from the filter 31 to the LCD 37 via the filter 32.

On the other hand, from the filter 31 to the filter 3
The optical path to the LCD 38 via the mirrors 2 and 33 and the mirror 34b is longer than the above-mentioned optical paths, and between the filter 32 and the filter 33 and between the filter 33 and the mirror 34b in order to make the actual optical path length the same. Are provided with relay lenses 35a and 35b, respectively. It is not always necessary to provide two relay lenses, and one relay lens corresponding to the two relay lenses 35a and 35b is used.
One relay lens may be provided somewhere on the optical path from the filter 32 to the LCD 38.

The projection section 40 includes a projection lens 41 and a total reflection mirror 42. The projection lens 41 is a cross prism 3
The light after the modulation synthesized by 9 is emitted upward, and the mirror 42 reflects the light from the projection lens 41 toward the front screen 50. As a result, light representing an image of three colors forms an image on the screen 50, and
A color image is displayed above.

Since the projection display device 1 is configured as a television, the size of the screen 50 and the cross prism 3
The optical path length from 9 to the screen 50 is constant,
Therefore, it is not necessary for the projection lens 41 to have a focus adjustment function. However, in order to prevent the display image from being blurred due to a small assembly error, the projection lens 41 is set so that the focus can be finely adjusted.

The structure in which the light projected from the projection lens 41 is reflected by the total reflection mirror 42 enables the projection lens 41 to be kept small while keeping the size of the projection display device 1 small.
It is possible to display a large image by lengthening the optical path from to the screen 50. The total reflection mirror 42 may be flat, or may be convex to make the displayed image larger. The position and orientation of the modulation unit 30 and the projection lens 41 are changed so that the optical axis of the projection lens 41 is
, The mirror 42 can be omitted.

The screen 50 is made semi-transparent with fine irregularities uniformly formed on the surface, and the light projected and imaged from the back side of the screen 50 is guided to the front side and diffused. Therefore, an observer located on the front side of the screen 50 can view an image on the screen 50 from any direction on the front side of the screen 50.

In the projection display device 1, as described above, the replaceable lamp 81 is used as the light source. However, instead of replacing the lamp 81 alone, the lamp unit is replaced by using a lamp unit incorporating the lamp 81. I do. The metal halide lamp becomes hot at the time of lighting, and may explode if flammable dirt such as grease adheres to the surface of the glass of the lamp. By replacing the lamp unit instead of the lamp alone, the possibility that the user directly touches the lamp and sebum adheres to the glass is greatly reduced, and the risk of explosion is prevented.

The metal halide lamp has a feature that the amount of light emission is large, but also has a disadvantage that the glass deteriorates as the lighting time increases, and the glass is exploded when used in a state of advanced deterioration. For this reason, considering the relationship between the lighting time and the degree of deterioration,
The lifetime that guarantees the safe lighting time is determined at the time of manufacture. In the projection display device 1 and the lamp unit used for the same, measures are taken against the risk of turning on the lamp for a long time.

FIG. 2 shows the configuration of the lamp unit 80 and the mounting portion 21 used in the projection display device 1, and FIG. 3 shows the mounting portion 21 with the lamp unit 80 mounted. The lamp unit 80 includes a metal halide lamp 81, a parabolic total reflection mirror (reflection umbrella) 82, a lamp holding unit 83 that integrally holds the lamp 81 and the mirror 82 and is provided with a terminal 84 of the lamp 81, and a lamp 81. And a memory 85 for storing various information relating to The lamp 81 is disposed at the focal position of the mirror 82, and the light reflected by the mirror 82 becomes substantially parallel light.

The memory 85 is a nonvolatile and rewritable E
It is an EPROM having input / output terminals 86 and fixed to the lamp holding section 83. When the lamp unit 80 is manufactured, the memory 85 stores the rated output of the lamp 81, the luminous efficiency, the life when the lamp is lit at the rated output, the relationship between the output and the deterioration speed, the relationship between the output and the color temperature of the emitted light, and the lamp 81. The relationship between the temperature and the ignition voltage required for lighting is written. The projection display device 1 reads these pieces of information on the lamp 81 from the memory 85 and uses them for controlling the operation. In particular, regarding the life of the lamp 81, when the lamp 81 is turned on, the remaining life is calculated from the lighting time, and the content stored in the memory 85 is rewritten.

The mounting portion 21 is formed in a cylindrical shape, has an opening 21a at the front end, and has a door 21b at the rear end. The door 21b is provided with a terminal 21c for supplying power to the lamp 81 and a terminal 21d for inputting and outputting data from and to the memory 85. The lamp unit 80 is inserted into the mounting portion 21 from the rear as indicated by the arrow in FIG. 2, the front edge of the parabolic mirror 82 abuts on the periphery of the opening 21a, and the terminal of the closed door 21b is closed. The terminals 84 and 86 abut against the mounting portions 21c and 21d, respectively.
Fixed inside.

In order to keep the door 21b closed, the door 2
A claw 21e is formed at the end of 1b, and a groove 21f that engages with the claw 21e is formed on the outer peripheral surface of the mounting portion 21.
The door 21b has elasticity, and the engagement between the claw 21e and the groove 21f is released by lightly operating the end with a fingertip,
The door 21b opens. Therefore, the attachment / detachment of the lamp unit 80 to / from the mounting portion 21 is easy.

FIG. 4 shows an outline of a circuit configuration relating to the display of an image on the projection display device 1. The projection display device 1 includes a mounting unit 2
Lighting circuit 6 that supplies power to 1 to light lamp 81
1. Lamp 8 mounted on mounting section 21 at lighting position A
1, a temperature sensor 62 for detecting the temperature, a door open / close sensor 63 for detecting the open / close state of the door 11 provided opposite the non-lighting position B, a driver 64 for driving the motor 24, A switch 65 is provided that closes when the lighting position is in the non-lighting position B and opens when the lighting position is between the lighting position A and the non-lighting position B.

From the lighting circuit 61, a power supply wiring 61 is provided.
a is provided up to the lighting position A. The end of the wiring 61a is exposed to the lighting position A as a connection terminal, and is automatically connected to the terminal 21c of the mounting portion 21 that has moved to the lighting position A. On the other hand, no wiring for power supply is provided from the lighting circuit 61 to the non-lighting position B, and no power is supplied to the mounting portion 21 at the non-lighting position B.

The projection display device 1 also drives the LCDs 36, 37 and 38 according to the R, G and B signals to modulate the R, G and B lights.
6. A WB adjustment unit 67 that supplies the R signal, the G signal, and the B signal to the LCD driver 66, and adjusts the white balance (WB) of the displayed image by changing the intensity of these three signals. Light emitting diode (LED) 6
8, 69, an operation unit 70 and a controller 71 operated by a user.

The projection display device 1 also includes a signal processing circuit (not shown) well-known in the television arts for receiving a television signal and generating an RGB signal.
The RGB signal is supplied to the adjustment unit 67 from the signal processing circuit. Note that the RGB signals reproduced by the video reproducing device can be supplied to the WB adjustment unit 67.

The controller 71 is composed of a microcomputer. The lighting circuit 61 turns on the lamp 81, the driver 64 drives the motor 24, and the LCD driver 66
Of LCDs 36, 37, and 38 by WB adjustment unit 67
, And controls the operation of a signal processing circuit (not shown). The controller 71 is a lamp 81
The controller 71 has a timer 71c for measuring the time it has been turned on. At the lighting position A and the non-lighting position B from the controller 71, input / output wirings 71a and 71b of the memory 85 of the lamp unit 80 are provided, respectively. I have. The ends of the wires 71a and 71b are connection terminals, and are exposed at a lighting position A and a non-lighting position B.
It is automatically connected to the terminal 21d of the mounting portion 21 that has moved to the non-lighting position B.

The controller 71 automatically arranges the mounting portion 21 in which the lamp unit 80 having the remaining life of the lamp 81 is mounted at the lighting position A in order to avoid the danger of lamp rupture. For this purpose, the remaining life of the lamp 81 is read from the memory 85 of each lamp unit 80 before displaying an image. When there is no remaining life, that is, when the remaining life is 0 or less, the mounting portion 21 is set to “lighting disabled”, and when the lamp unit 80 is not mounted, the mounting portion 21 is set to “lighting disabled”. . Lamp 81
The mounting part 21 to which the lamp unit 80 having the remaining life of the lamp is mounted is set to “lighting enabled”.

When the mounting portion 21 at the lighting position A cannot be turned on, it is determined whether or not the mounting portion 21 at the non-lighting position B can be turned on. A. When it is impossible to light any of the mounting portions 21 in the lighting position A and the lighting position B, the LED 68 is turned on to issue a warning.

When ending the display of an image, that is, when turning off the lamp 81 at the lighting position A, the controller 71 calculates the latest value of the remaining life by subtracting the lighting time measured by the timer 71c from the remaining life before lighting. The calculated value is written in the memory 85 of the lamp unit 80 to update the stored remaining life. At this time, the remaining life is calculated at the time when the display end instruction is given from the user via the operation unit 70, and when the calculated remaining life is equal to or less than the predetermined time H, the mounting unit 21 at the non-lighting position B is turned off. It is determined whether lighting is possible. If the mounting portion 21 at the non-lighting position B cannot be turned on, a message indicating that the lamp unit 80 having the remaining life of the lamp 81 should be mounted to the mounting portion 21 at the non-lighting position B is displayed on the screen 50 for about several seconds. For a short time. Thereafter, the lamp 81 is turned off.

This display is, for example, "The lamp is approaching the end of its life. Install a new spare lamp in the spare lamp holder." The user who sees this display mounts a new lamp unit 80 in the mounting portion 21 at the non-lighting position B at an appropriate time.

The predetermined time H is set to be about twice or more the average value of one image display time. In the projection display device 1 of the present embodiment configured as a television, 3 to 4 hours are appropriate. This is to ensure the remaining life and enable the next image display even when a new lamp unit 80 is not mounted. Even if the remaining life is exhausted while the lamp 81 is turned on, the lamp 81
Continue lighting. Even if the remaining life is exhausted, the lamp does not immediately burst, and the display of the image must be interrupted in order to arrange the lamp 81 at the non-lighting position B at the lighting position A to avoid the inconvenience. It is. In order to shorten the lighting time beyond the service life as much as possible, the predetermined time H is preferably set to about twice or more the average value of the time of one image display.

The user opens the door 11 and mounts a new lamp unit 80 on the mounting portion 21 at the non-lighting position B. The controller 71 controls the lighting circuit 61 to turn on the lamp 81 at the lighting position A. The driving of the motor 24 is prohibited while the temperature of the lamp 81 at the lighting position A detected by the temperature sensor 62 is equal to or higher than a predetermined temperature.
As a result, the high-temperature lamp 81, which has just been turned off, moves to the non-lighting position B, and the danger of the user touching and burning the lamp 81 is prevented.

The controller 71 prohibits the driving of the motor 24 while the door opening / closing sensor 63 detects that the door 11 is open, and detects that the door 11 is opened while the motor 24 is driving. Motor 24
To stop. Accordingly, the mounting portion 21 rotates only while the door 11 is closed, and the danger of the user's fingertip being pinched by the rotating mounting portion 21 or the holding portion 22 is prevented. While the door 11 is open, the LED 69 is turned on to warn of forgetting to close.

The driving of the motor 24 for rotating the mounting section 21 is stopped when the switch 65 is closed. Therefore, even if the driving of the motor 24 is interrupted due to the opening of the door 11 and the position of the mounting unit 21 cannot be determined, the driving of the motor 24 is resumed, so that the mounting unit 21 is turned on and off. B can be reliably positioned.

In a metal halide lamp as an arc discharge tube, an ignition voltage for starting lighting differs depending on whether the lamp is at a low temperature or a high temperature. At low temperatures, the enclosed gas is easily ionized, and can be turned on with a low ignition voltage. On the other hand, at a high temperature, the sealed gas is hardly ionized, and cannot be turned on unless a high ignition voltage of about 2 to 10 times the low ignition voltage is applied.

In the projection display device 1, the lighting circuit 61 is configured to output two high and low ignition voltages in order to enable the image display to be resumed immediately after the end of the image display. The controller 71 gives an instruction to the lighting circuit 61 to output one of the ignition voltages depending on whether the temperature of the lamp 81 at the lighting position A detected by the temperature sensor 62 is equal to or lower than a predetermined temperature. . By applying a low ignition voltage when the detected temperature is equal to or lower than a predetermined temperature, the lamp 81 can be turned on while preventing damage to the electrodes, and by applying a high ignition voltage when the temperature is high, the light is turned off. The lamp can be reliably turned on immediately after.

Note that, instead of selecting the ignition voltage according to the detected temperature, it is also possible to select the ignition voltage according to the elapsed time from turning off the light. For example, a high ignition voltage is selected within 80 seconds after the light is turned off, and a low ignition voltage is selected if the time exceeds 80 seconds after the light is turned off. Alternatively, an ignition voltage intermediate between two high and low ignition voltages may be set, and any one of the ignition voltages may be selected according to the temperature of the lamp 81 or the elapsed time after the lamp 81 is turned off. Further, the ignition voltage may be continuously varied within a range between the lowest voltage and the highest voltage which is about ten times the same, and the ignition voltage according to the state of the lamp 81 may be applied.

When the low-temperature spare lamp 81 at the non-lighting position B is moved to the lighting position A when the lamp 81 at the lighting position A is at a high temperature, only a low ignition voltage is output. However, it is possible to restart the image display immediately after the end of the image display. However, the spare lamp is not always installed at the non-lighting position B, and even if it is installed, the spare lamp does not always have the remaining life.
The control lacks certainty. In addition, since the high-temperature lamp 81 immediately after the light is turned off is arranged at the non-lighting position B, there is a risk that the user may touch and burn the lamp. The above control of re-lighting the lamp 81 at the lighting position A by preparing two high and low ignition voltages is preferable in terms of both reliability and safety.

It is desirable that the brightness of the displayed image can be changed according to the brightness of the environment in order to improve the visibility of the image and reduce the power consumption. For this reason, in the projection display device 1, in order to continue lighting, the lighting circuit 61
, The voltage applied to the lamp 81 (hereinafter, referred to as a steady voltage) is made variable, and the controller 71 detects a brightness setting instruction given by the user via the operation unit 70,
It changes according to the instructions. The light emission amount of the lamp 81 changes according to the level of the steady voltage, and the screen 5
The amount of light projected to 0 changes and the brightness of the image changes.

In the metal halide lamp, when the amount of light emission, that is, the output wattage changes, the color temperature of the emitted light also changes. FIG. 9 illustrates the relationship between the output wattage and the color temperature. When the output wattage is high, the color temperature is low, and when the output wattage is low, the color temperature is high. Light is observed to be reddish at a low color temperature and bluish at a high color temperature. Therefore, in order to keep the color of the displayed image constant irrespective of its brightness, the setting of the white balance must be adjusted in accordance with the steady voltage applied to the lamp 81.

Therefore, the controller 71 controls the lighting circuit 6
1 according to the steady-state voltage value indicated to the LCD driver 66.
To change the intensity of each of the R, G, and B signals output to
An instruction is given to the B adjusting unit 67. Specifically, the intensity of the B signal with respect to the R signal is relatively increased when the steady voltage is increased, and relatively decreased when the steady voltage is decreased. This reduces redness when the image of the lamp 81 emits a large amount of light and displays an image brightly, and reduces blueness when the amount of light of the lamp 81 decreases and displays the image darkly, so that an image of a constant hue can always be displayed. it can.

As described above, the relationship between the output and the color temperature is stored in the memory 85 of the lamp unit 80, and the controller 71 reads out the relationship and uses it for controlling the white balance adjustment by the WB adjustment unit 67. Therefore, even if the lamps 81 having different wattages are used, an image having an appropriate color can always be displayed. Instead of storing the relationship between the output wattage and the color temperature in each lamp unit 80, the controller 71 stores the general relationship between the output wattage and the color temperature of the metal halide lamp, and stores this in the white balance. It may be used for adjustment control.

The operation section 70 is provided with an operation member for instructing the setting of the color tone.
The ratio of the R, G, and B signals obtained from the relationship between the output wattage and the color temperature is corrected in accordance with an instruction from the user. Therefore, the user can also set the color of the image to be displayed according to his / her preference.

Since the deterioration speed of the lamp 81 varies depending on the output at the time of lighting, in order to correctly determine the remaining life,
It is necessary to consider not only the time during which the lamp 81 is kept on, but also the output at that time. Therefore, in the projection display device 1, the time measured by the timer 71c for measuring the lighting time of the lamp 81 is variable. As described above, the lamp 81
Is stored in the memory 85 of the lamp unit 80, and the controller 71 refers to this information to change the clocking speed of the timer 71c according to the steady voltage value instructed to the lighting circuit 61. . Thereby, even if the output of the lamp 81 is changed according to the brightness of the environment,
The remaining time can be calculated correctly.

The control of the image display operation in the projection display device 1 will be described with reference to FIGS. FIG. 5 is a flowchart showing an outline of the entire control operation. When the power switch is operated to start supplying power to each unit of the projection display device 1 (step # 5), the controller 71
First, based on the presence or absence of the lamp unit 80 in the mounting unit 21 and the remaining life of the lamp 81 stored in the memory 85, a lamp for checking whether or not the lamp of each mounting unit 21 can be turned on. A check is performed, and the mountable unit 21 that can be turned on is arranged at the lighting position A (# 10).

Next, it is determined whether or not the start of the display is instructed by the switch for instructing the start and the end of the display provided on the operation unit 70 (# 15). If the start of display is not instructed, it waits for the instruction. When there is an instruction, a lighting start process for applying the ignition voltage to light the lamp 81 at the lighting position A is performed (# 2).
0). Thus, a color image corresponding to the television signal is displayed on the screen 50.

The display is continued until the end is instructed by the switch for instructing the start and the end of the display (# 3).
0). During this time, the lamp 81 is turned on according to the instruction from the user.
Is performed to change the brightness of the image by changing the steady-state voltage applied to # 1 (# 25). When the brightness of the image is changed, the process of adjusting the white balance and the process of changing the clock speed of the timer 71c are performed at the same time.

When there is an instruction to end the display (# 30), the remaining life of the lamp 81 is calculated, and if necessary, a process for prompting the replacement of the lamp unit 80 is performed (# 35). And
The lamp 81 is turned off (# 40), and the calculated remaining life is written into the memory 85 of the lamp unit 80 at the lighting position A (# 45). In addition, in preparation for the next display, step #
The same lamp check processing as in step 10 is performed (# 50), and the power supply is cut off by operating the power switch, thereby terminating the entire processing (# 55).

The flow of the lamp check process in steps # 10 and # 50 is shown in the flowchart of FIG. First, from the memory 85 of the lamp unit 80 mounted on the mounting portion 21 at the lighting position A and the lighting position B,
The information about the lamp 81 including the remaining life is read (step # 105). Then, depending on whether or not the lamp unit 80 has been mounted on the mounting portion 21 and whether or not the lamp 81 has a remaining life, as described above,
It is determined whether the mounting unit 21 can be turned on or off (# 110).

Next, it is determined whether or not the mounting portion 21 at the lighting position A can be turned on (# 115), and if it can be turned on, the process returns to FIG. When the mounting portion 21 at the lighting position A cannot light, it is determined whether the mounting portion 21 at the non-lighting position B can light (# 120). Mounting part 21 in non-lighting position B
If the lamp 81 cannot be turned on, the LED 68 is turned on to warn that the lamp 81 having the remaining life is not mounted (# 125), and the entire process is terminated.

When the mounting portion 21 at the non-lighting position B is lightable, the lamp 8 at the lighting position A detected by the temperature sensor 62
No. 1 is determined to be equal to or higher than a predetermined temperature (# 13).
0) If the temperature is equal to or higher than the predetermined temperature, wait until the temperature becomes lower than the predetermined temperature. If the temperature of the lamp 81 at the lighting position A is lower than the predetermined temperature, the door 1 detected by the door open / close sensor 63
1 is determined. When the door 11 is open, LE
By illuminating D69, a warning is given not to switch the lamp unit 80 (# 140), and the system waits for the door 11 to be closed.

When the door 11 is closed, the motor 2
By rotating the holding unit 22 by the drive of No. 4 to move the mounting unit 21 at the lighting position A to the non-lighting position B and the mounting unit 21 at the non-lighting position B to the lighting position A,
Is switched (# 145). Thus, the lamp 81 having the remaining life is arranged at the lighting position A, and the display can be started at any time, and the process returns to FIG.

The flow of the lighting start process in step # 20 of FIG. 5 is shown in the flowchart of FIG. First, based on the temperature of the lamp 81 at the lighting position A detected by the temperature sensor 62, it is determined whether or not re-lighting is performed immediately after turning off the light (step # 205). If the detected temperature is equal to or lower than the predetermined temperature and the light is not turned on immediately after the light is turned off, a standard ignition for applying a low ignition voltage to the lamp 81 from the lighting circuit 61 is performed (# 210). , And when the light is turned on immediately after the light is turned off, a high-pressure ignition for applying a high ignition voltage is performed (# 21).
5). Then, in order to measure the lighting time used for calculating the remaining life, the timer 71c is started (# 220), and the process returns to the process of FIG.

The ramp 81 in step # 35 of FIG.
FIG. 8 is a flowchart showing the flow of the process of calculating the remaining life and the process of requesting replacement of the lamp unit 80. First, from the remaining life read in step # 10 (FIG. 6, step # 105) of FIG. 5, step # 20 (FIG. 7, step # 22)
The remaining time of the lit lamp 81 at the lighting position A is calculated by subtracting the measurement time of the timer 72c started in step 0) (step # 305). Next, it is determined whether or not the calculated remaining life exceeds the predetermined time H (# 310), and if it has, the process returns to the process of FIG.

If the remaining life is equal to or less than the predetermined time H, it is determined whether or not the mounting portion 21 at the non-lighting position B is lightable (# 315). When the mounting portion 21 at the non-lighting position B is lightable, the process returns to the process of FIG.
The above message indicating that the lamp unit 80 having the remaining life should be mounted to the mounting portion 21 at the non-lighting position B is displayed (# 320), and the process returns to FIG.

This message need only be displayed for a time sufficient for the user to read it. Since the display time is as short as about several seconds, there is almost no error in the remaining time to be written to the memory 85 in step # 45 of FIG. If it is necessary to write a stricter remaining time into the memory 85, step #
The display time of this message may be subtracted from the remaining time calculated in 305.

As described above, in the projection type image display apparatus 1 of this embodiment, the remaining life of the lamp is stored in the lamp unit, and only the lamp having the remaining life is turned on. Is replaced so as to prevent the user from directly touching the lamp, so that there is almost no danger of the lamp exploding. Also, since only the lamp in the non-lighting position is replaceable, the high-temperature lamp is not moved to the non-lighting position, and the lamp moving mechanism is not driven when the lamp replacement door is open, There is no risk of the user being injured such as a burn.

Further, the brightness of the displayed image can be adjusted according to the environmental conditions, and the white balance is adjusted according to the brightness of the displayed image. And wasteful power consumption can be avoided. In addition, a high ignition voltage can be applied, and the display of an image can be easily restarted immediately after the end of the image display. Furthermore, since the necessity of lamp replacement is determined in advance and the fact is displayed at an appropriate time, it is easy to prepare a spare lamp.

Due to such features, the projection type image display device 1 has extremely high security, high quality of display image, excellent operability, and low power consumption, and is suitable as a home television. ing. Note that a sensor for detecting the brightness of the environment may be provided to adjust the brightness of the display image in accordance with the brightness of the environment. In this configuration, the power consumption can be further reduced. . Also in that case, the white balance is adjusted according to the brightness of the image to be displayed.

Although the example of the rear projection type television is shown here, the present invention can also be applied to a projection type image display device having a separate screen. For example, it is also suitable for a front projection type data projector. In this case, the focus adjustment function is provided on the projection unit so that the image formation position of the projection light can be changed according to the distance to the screen and the size of the display range can be changed according to the size of the screen. And a zoom function.

[0074]

According to the projection type image display device of the present invention, since the lamp can be turned on immediately after the arc discharge lamp is turned off, the display of the image is immediately resumed after the display of the image is completed. It is very easy to use. Moreover, since the same lamp is turned on again, the device configuration is not complicated, and a bright image can always be provided. By setting the ignition voltage in three or more stages, it is possible to reduce damage to the electrodes of the lamp and to maintain the performance of the lamp for a long period of time.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a configuration related to image display of an embodiment of a projection-type image display device of the present invention configured as a rear-projection television.

FIG. 2 is a diagram showing a configuration of a mounting portion of the projection type image display device and a lamp unit mounted on and used in the mounting portion.

FIG. 3 is a diagram showing a mounting portion of the projection type image display device in a state where a lamp unit is mounted.

FIG. 4 is a diagram schematically showing a circuit configuration related to image display of the projection type image display device.

FIG. 5 is a flowchart showing an outline of the entire control operation relating to image display of the projection type image display device.

FIG. 6 is a flowchart showing a lamp check process of the projection type image display device.

FIG. 7 is a flowchart showing a process of starting lighting of the projection type image display device.

FIG. 8 is a flowchart showing a process of calculating a remaining life of a lamp of the projection type image display apparatus and a process of requesting replacement of a lamp unit.

FIG. 9 is a diagram showing an example of the relationship between the output wattage of a metal halide lamp and the color temperature.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rear projection television (projection image display device) 10 housing 11 housing door 20 light source unit 21 mounting unit 21a opening 21b mounting unit door 21c power supply terminal 21d input / output terminal 22 holding unit 23 holding unit rotation axis 24 motor 25 Motor rotating shaft 30 Modulation unit 31, 32, 33 Color filter 34a, 34b Total reflection mirror 35a, 35b Relay lens 36, 37, 38 Transmission liquid crystal panel (LCD) 39 Cross prism 40 Projection unit 41 Projection lens 42 Total reflection mirror 50 Screen 61 Lighting circuit 61a Power supply wiring 62 Temperature sensor 63 Door open / close sensor 64 Motor driver 65 switch 66 LCD driver 67 White balance adjustment unit 68, 69 Light emitting diode 70 Operation unit 71 Controller 71a, 71b Input / output wiring 80 Puyunitto 81 metal halide lamp 82 total reflection mirror 83 lamp holding portion 84 lamp terminal 85 memory 86 memory terminal A turn-on position B OFF position

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideki Nagata 2-3-13 Azuchicho, Chuo-ku, Osaka City Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Akira Kawabata 2-3-3 Azuchicho, Chuo-ku, Osaka City No. 13 Osaka International Building Minolta Co., Ltd.

Claims (1)

[Claims] 1. A projection type image display device using an arc discharge lamp as a light source for image projection, comprising: lighting means for outputting a plurality of levels of ignition voltage, wherein the ignition voltage supplied to the arc discharge lamp is A projection-type image display device, wherein the ignition voltage is selected from among a plurality of levels of ignition voltage according to the state of an arc discharge lamp.