JP6124359B2 - Projector and control method thereof - Google Patents

Description

  The present invention relates to a projector and a control method thereof.

  In recent years, in projectors that project video light based on video signals, reducing power consumption during projection has become an important issue.

  Therefore, Patent Document 1 (Japanese Patent Application Laid-Open No. 11-65528) includes a lamp and a display element that attenuates light emitted from the lamp in accordance with a video signal and emits it as video light, and has a predetermined period. A projector is disclosed that reduces the lamp power and corrects the video signal as the maximum value (peak level) of the amplitude of the video signal is lower. According to this projector, when the lamp power is lowered, the image signal is corrected so that the amount of the image light is the same as that when the lamp power is projected without lowering the lamp power. It is possible to project with less power consumption.

JP-A-11-65528

  In general, a discharge lamp is used as a projector lamp. During the operation of the lamp, a halogen cycle occurs in which the electrode material evaporated from the electrodes accompanying the discharge between the electrodes of the lamp adheres to the electrodes again by the action of the halogen gas sealed in the arc tube of the lamp. By appropriately controlling the halogen cycle, it is possible to suppress lamp life reduction and flicker generation. Here, in order to appropriately control the halogen cycle, it is important to control the lamp power and the lamp temperature.

  In general, the lamp temperature is controlled by cooling the lamp using a fan. Here, if the lamp power is changed rapidly, the lamp temperature also changes rapidly, and the cooling using the fan is not in time, making it difficult to keep the lamp temperature in an appropriate state.

  In the projector disclosed in Patent Document 1, since the lamp power is changed without considering the lamp temperature control, it is difficult to keep the lamp temperature in an appropriate state due to the change in the lamp power. If the lamp temperature is not kept in an appropriate state, the characteristics of the lamp will deteriorate, causing problems such as a reduction in life and occurrence of flicker.

  An object of the present invention is to provide a projector capable of solving the above-described problems and a control method therefor.

In order to achieve the above object, the projector of the present invention provides:
A projector that projects video light based on a video signal corresponding to an external video signal given from the outside,
A lamp,
A display element that modulates the light emitted from the lamp according to the amplitude of the video signal and emits the light as the video light;
In accordance with the external video signal, a power value of lamp power for driving the lamp is specified, and a power control signal for gradually changing the lamp power to the specified power value is generated, and the lamp is set to the specified power value. Specifying the amplitude value of the video signal in which the light amount of the video light projected when the power is changed is substantially the same as the light amount of the video light when projected without changing the lamp power; A control unit that generates an amplitude control signal that gradually changes the amplitude of the video signal to the specified amplitude value;
A lamp driving unit that supplies lamp power to the lamp according to the power control signal generated by the control unit;
An amplitude modulation unit that adjusts the amplitude of the video signal in accordance with the amplitude control signal generated by the control unit and drives the display element in accordance with the video signal in which the amplitude has been adjusted,
When the control unit outputs the power control signal that lowers the lamp power when the amplitude of the external video signal decreases, increases the lamp power when the amplitude of the external video signal increases, and increases the lamp power Even if the amplitude of the external video signal decreases, the lamp power is controlled to increase until the power value specified before the amplitude of the external video signal decreases .

In order to achieve the above object, a projector control method according to the present invention includes:
A control method for a projector, comprising: a lamp; and a display element that modulates light emitted from the lamp in accordance with an amplitude of a video signal corresponding to an external video signal given from outside and emits the light as video light. And
The control unit specifies a power value of lamp power for driving the lamp in accordance with the external video signal, generates a power control signal for gradually changing the lamp power to the specified power value, and the specified The amplitude value of the video signal in which the light quantity of the image light projected when the lamp power is changed to the power value is substantially the same as the light quantity of the video light when projected without changing the lamp power And generating an amplitude control signal that gradually changes the amplitude of the video signal to the specified amplitude value,
A lamp driving unit supplies lamp power corresponding to the power control signal generated by the control unit to the lamp,
An amplitude modulation unit adjusts the amplitude of the video signal in accordance with the amplitude control signal generated by the control unit, and drives the display element in accordance with the video signal in which the amplitude is adjusted,
When the control unit outputs the power control signal that decreases the lamp power when the amplitude of the external video signal decreases, increases the lamp power when the amplitude of the external video signal increases, and increases the lamp power Even if the amplitude of the external video signal decreases, the lamp power is controlled to increase until the power value specified before the amplitude of the external video signal decreases .

  According to the present invention, the projector can project the same amount of image light with less power consumption, suppress the change in lamp temperature, and reduce the deterioration of lamp characteristics.

It is a figure which shows the structure of the projector of one Embodiment of this invention. It is a figure which shows the relationship between the lamp electric power value with respect to the peak level of a video signal, and the amplitude value of a video signal. It is a figure for demonstrating operation | movement of the projector shown in FIG. It is a figure for demonstrating other operation | movement of the projector shown in FIG.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings.

  FIG. 1 is a diagram showing a configuration of a projector 10 according to an embodiment of the present invention.

  A projector 10 shown in FIG. 1 includes a peak level detection unit 11, a gain calculation unit 12, a lamp driving unit 13, a lamp 14, a temperature control unit 15, an amplitude modulation unit 16, a display element driving unit 17, Display element 18. In FIG. 1, a white arrow indicates a light beam. The gain calculation unit 12 is an example of a control unit.

  The video signal given from the outside is input to the peak level detection unit 11 and the amplitude modulation unit 16.

  The peak level detection unit 11 detects a peak level in a predetermined period of the input video signal and outputs a peak level detection value to the gain calculation unit 12.

  The gain calculation unit 12 specifies the power value P of the lamp power and the amplitude value A of the video signal according to the peak level detection value input from the peak level detection unit 11. The gain calculation unit 12 specifies the power value P and the amplitude value A as follows, for example.

First, the gain calculation unit 12 calculates the gain G = V ₁ / V ₀ . V ₁ is a peak level detection value, and V ₀ is a predetermined value set in advance as a standard peak level of the video signal. Hereinafter, V ₀ is referred to as a reference peak level.

Next, the gain calculation unit 12 specifies the power value P from the power value P = P ₀ · G. P ₀ is a predetermined value set in advance as a standard lamp power value. Hereinafter, P ₀ is referred to as a reference lamp power value.

Further, the gain calculation unit 12 specifies the amplitude value A from the amplitude value A = A ₀ / G. A ₀ is the amplitude value of the original video signal input from the outside.

  FIG. 2 is a diagram illustrating a relationship between the peak level detection value and the power value P and the amplitude value A specified according to the peak level detection value. In FIG. 2, the horizontal axis indicates the peak level detection value, and the peak level detection value increases as it goes to the right. In FIG. 2, the solid line indicates the power value P, and the dotted line indicates the amplitude value A.

  As shown in FIG. 2, the power value P is proportional to the peak level detection value, and the amplitude value A is inversely proportional to the peak level detection value.

  When the power value P and the amplitude value A are specified, the gain calculation unit 12 generates a power control signal that gradually changes the lamp power up to the power value P and outputs the power control signal to the lamp driving unit 13. The gain calculation unit 12 generates an amplitude control signal that gradually changes the amplitude of the video signal up to the amplitude value A, and outputs the amplitude control signal to the amplitude modulation unit 16.

  The lamp drive unit 13 supplies the lamp 14 with lamp power corresponding to the power control signal input from the gain calculation unit 12.

  The lamp 14 is driven by the lamp power supplied from the lamp driving unit 13 and emits light that illuminates the display element 18.

  The temperature control unit 15 controls the lamp temperature of the lamp 14 using, for example, a fan.

  The amplitude modulation unit 16 adjusts the amplitude of the original video signal in accordance with the amplitude control signal input from the gain calculation unit 12, and outputs the video signal with the adjusted amplitude to the display element driving unit 17.

  The display element driving unit 17 drives the display element 18 in accordance with the video signal input from the amplitude modulation unit 16.

  The display element 18 is driven by the display element driving unit 17, modulates the light emitted from the lamp 14 according to the amplitude of the video signal, and emits it as video light. Here, it is assumed that the light emitted from the lamp 14 increases as the amplitude of the video signal decreases, and attenuates as the amplitude of the video signal increases. In other words, the video light is darker as the amplitude of the video signal is smaller, and brighter as the amplitude of the video signal is larger.

  Next, the operation of the projector 10 will be described with reference to FIG.

  3A shows a timing chart of peak level detection values, FIG. 3B shows a timing chart of lamp power values, and FIG. 3C shows a timing chart of amplitude values of video signals. Indicates.

  The peak level detection unit 11 detects the peak level of the video signal given from the outside, and outputs the peak level detection value to the gain calculation unit 12.

It is assumed that the peak level detection value of the video signal has dropped to 80% of the reference peak level V ₀ at time t1. In this case, the gain calculation unit 12 calculates G = 0.8, sets the power value P to 0.8 times the reference lamp power value P ₀ , that is, 80%, and sets the amplitude value A to the original video signal. 1 / 0.8 times, that is, 125%.

  Next, the gain calculation unit 12 outputs a power control signal for gradually decreasing the lamp power to the power value P to the lamp driving unit 13, and an amplitude control signal for gradually increasing the amplitude of the video signal to the amplitude value A. Output to the amplitude modulation section 16.

  In response to the power control signal, the lamp driving unit 13 gradually decreases the lamp power to the power value P from time t1 to time t2, as shown in FIG. The time from time t1 to time t2 is approximately several seconds to several tens of seconds.

  The amplitude modulation unit 16 gradually increases the amplitude of the video signal to the amplitude value A from time t1 to time t2, as shown in FIG. 3C, according to the amplitude control signal.

It is assumed that the peak level detection value has increased to the reference peak level V ₀ at time t4. In this case, the gain calculation unit 12 calculates G = 1.0, sets the power value P to 1.0 times the reference lamp power value P ₀ , that is, 100%, and sets the amplitude value A to the original video signal. Is 1.0 times, that is, 100%.

  Next, the gain calculation unit 12 outputs a power control signal for gradually increasing the lamp power to the power value P to the lamp driving unit 13, and an amplitude control signal for gradually decreasing the amplitude of the video signal to the amplitude value A. Output to the amplitude modulation section 16.

  In response to the power control signal, the lamp driving unit 13 gradually increases the lamp power to the power value P from time t4 to time t6 as shown in FIG.

  The amplitude modulation unit 16 gradually decreases the amplitude of the video signal to the amplitude value A from time t4 to time t6 as shown in FIG.

  When the lamp power is lowered, the light amount of the lamp 14 is also reduced, but the amplitude of the video signal is increased in accordance with the decrease of the lamp power so that the light emitted from the lamp 14 by the display element 18 is attenuated small. Therefore, it is possible to project image light having the same brightness as that in the case where the lamp power is not lowered with less power consumption. Further, since the lamp power is gradually changed, the lamp temperature does not change rapidly, and the temperature control unit 15 can maintain the lamp temperature in an appropriate state.

  Since the maximum amplitude of the video signal that can be expressed by the display element 18 is limited, if the amplitude of the video signal is increased too much, the video signal is saturated and a problem that the bright gradation cannot be reproduced occurs in the projected video. .

  Therefore, in the following, a method for controlling the amplitude value of the video signal different from that shown in FIG.

  FIG. 3D shows an example of a timing chart of the amplitude values of the different video signals.

  First, the case where the peak level of the video signal increases at time t4 will be described.

  When the gain calculation unit 12 specifies the power value P and the amplitude value A, the gain calculation unit 12 outputs the power control signal to the lamp driving unit 13 and the amplitude control signal to the amplitude modulation unit 16.

  Here, the gain calculation unit 12 makes the amplitude control signal, which is the time for changing the amplitude of the video signal to the amplitude value A, shorter than the power control time, which is the time for changing the lamp power to the power value P. Is output to the amplitude modulation section 16.

  The amplitude modulation unit 16 changes the amplitude of the video signal according to the amplitude control signal. Specifically, as shown in FIG. 3 (d), the amplitude modulation unit 16 amplitudes the amplitude of the video signal from time t4 to time t5 earlier than time t6 when the lamp power becomes the power value P. Decrease to value A.

After time t3, the amplitude of the video signal is 125% of the amplitude of the original video signal. Assuming that this amplitude is the maximum amplitude of the video signal that can be expressed by the display element 18, in this state, when the peak level of the video signal increases from 80% to 100% of the reference peak level V ₀ , the amplitude value is increased. A video signal having a gradation between 80% and 100% is saturated, and a bright gradation cannot be reproduced.

  However, as shown in FIG. 3D, the time during which the video signal is saturated is shortened by setting the amplitude of the video signal to the amplitude value A without waiting for the lamp power to reach the power value P. Can do. If the amplitude control time and the power control time do not match, the brightness of the projected image will change temporarily, but the change in brightness is less visible compared to when the video signal is saturated, Problems with projected images can be reduced. Further, by changing the lamp power and the amplitude of the video signal continuously instead of stepwise, it is possible to make the change in brightness less visible.

  Next, a case where the peak level of the video signal decreases at time t1 will be described.

  When the power calculation unit 12 specifies the power value P and the amplitude value A, the gain calculation unit 12 outputs a power control signal to the lamp driving unit 13 and outputs an amplitude control signal to the amplitude modulation unit 16.

  Here, the gain calculation unit 12 outputs an amplitude control signal that makes the amplitude control time longer than the power control time to the amplitude modulation unit 16.

  The amplitude modulation unit 16 adjusts the amplitude of the video signal according to the amplitude control signal. Specifically, as shown in FIG. 3D, the amplitude modulation unit 16 amplitudes the amplitude of the video signal from time t1 to time t3 later than time t2 when the lamp power becomes the power value P. Increase to value A.

Before time t1, the lamp power is 100% of the reference lamp power value P ₀ and the amplitude of the video signal is 100% of the amplitude of the original video signal. In this state, even if the peak level of the video signal becomes 80% of the reference peak level V ₀ , the video signal will not be saturated. Therefore, as shown in FIG. 3C, the amplitude control of the video signal and the lamp power control may be performed simultaneously. However, if the peak level of the video signal changes during control of the video signal amplitude or lamp power, the video signal may be saturated at that time. Therefore, the possibility that the video signal is saturated can be reduced by delaying the time taken for the amplitude control of the video signal from the time taken for the lamp power control. In other words, the saturation of the video signal is prevented by making the amplitude control time longer than the power control time.

  The operation when the peak level of the video signal changes while the lamp power is changing will be described with reference to FIG. 4A shows a timing chart of peak level detection values, FIG. 4B shows a timing chart of lamp power, and FIG. 4C shows a timing chart of amplitude values of video signals. Show. In FIG. 4, the same reference numerals are assigned to the same times as in FIG.

  When the peak level detection value decreases at time t1, the gain calculation unit 12 specifies the power value P and the amplitude value A, and outputs the power control signal to the lamp driving unit 13 and the amplitude control signal to the amplitude modulation unit 16. To do.

The lamp driving unit 13 reduces the lamp power according to the power control signal as shown in FIG. 4B, and the amplitude modulation unit 16 is shown in FIG. 4C according to the amplitude control signal. As described above, the amplitude of the video signal is increased. Here, it is assumed that the peak level of the video signal has increased to the reference peak level V ₀ at time t11 before the lamp power reaches the power value P.

  In this case, since the video signal may be saturated, the gain calculation unit 12 outputs a power control signal for increasing the lamp power to the lamp driving unit 13 and makes the amplitude control signal shorter than the power control time. Is output to the amplitude modulation section 16.

  As shown in FIG. 4C, the amplitude modulation unit 16 changes the amplitude of the video signal between time t11 and time t12 in accordance with the amplitude control signal. Further, the lamp driving unit 13 changes the lamp power between time t11 and time t13 as shown in FIG. 4B in accordance with the power control signal.

  Next, when the peak level detection value rises at time t4, the gain calculation unit 12 specifies the power value P and the amplitude value A, and sends the power control signal to the lamp driving unit 13 and the amplitude control signal to the amplitude modulation unit 16. Output to.

  As shown in FIG. 4B, the lamp driving unit 13 increases the lamp power from time t4 in response to the power control signal, and the amplitude modulation unit 16 in FIG. 4C according to the amplitude control signal. ), The amplitude of the video signal is reduced in the time from time t4 to time t14.

It is assumed that the peak level of the video signal has decreased at time t15 before the lamp power reaches the power value P.

  In this case, since there is no possibility that the video signal is saturated, the gain calculation unit 12 outputs a power control signal for increasing the lamp power to the lamp driving unit 13 as it is. Since the change direction of the lamp power remains constant, the temperature control unit 15 can easily control the lamp temperature.

  The operation of the lamp driving unit 13 when the peak level detection value decreases after time t13 is the same as the operation from time t1 to time t3 in FIG. The operation is the same as the operation from time t1 to time t3 in FIG.

  As described above, according to the projector 10 of the present embodiment, the power value of the lamp power is specified according to the peak level of the video signal, the lamp power is gradually changed to the power value, and the lamp power is changed according to the change in the lamp power. Then, the amplitude value of the video signal in which the light amount of the video light is constant is specified, and the amplitude of the video signal is gradually changed to the amplitude value.

  Therefore, image light with the same brightness as when the lamp power is not lowered can be projected with less power consumption, and the lamp power is gradually changed so that the lamp temperature does not change abruptly. It is possible to keep the temperature in an appropriate state and reduce the deterioration of the lamp characteristics.

  In this embodiment, the example in which the peak level of the video signal is detected has been described. However, if the peak level is detected even for a very small region, the peak level may be increased more than necessary. . Therefore, instead of the peak level of the video signal, a histogram indicating the frequency of occurrence of each of the plurality of gradations shown in the video signal may be used. By using such a histogram, control of lamp power and the like according to the brightness of the entire image can be performed in the same manner as in the embodiment described.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

Claims (6)

A projector that projects video light based on a video signal corresponding to an external video signal given from the outside,
A lamp,
A display element that modulates the light emitted from the lamp according to the amplitude of the video signal and emits the light as the video light;
In accordance with the external video signal, a power value of lamp power for driving the lamp is specified, and a power control signal for gradually changing the lamp power to the specified power value is generated, and the lamp is set to the specified power value. Specifying the amplitude value of the video signal in which the light amount of the video light projected when the power is changed is substantially the same as the light amount of the video light when projected without changing the lamp power; A control unit that generates an amplitude control signal that gradually changes the amplitude of the video signal to the specified amplitude value;
A lamp driving unit that supplies lamp power to the lamp according to the power control signal generated by the control unit;
An amplitude modulation unit that adjusts the amplitude of the video signal in accordance with the amplitude control signal generated by the control unit and drives the display element in accordance with the video signal in which the amplitude has been adjusted,
When the control unit outputs the power control signal that lowers the lamp power when the amplitude of the external video signal decreases, increases the lamp power when the amplitude of the external video signal increases, and increases the lamp power Even if the amplitude of the external video signal decreases , the projector performs control to increase the lamp power until the power value specified before the amplitude of the external video signal decreases . The projector according to claim 1, wherein
When the amplitude of the external video signal increases while outputting the power control signal for lowering the lamp power, the control unit has the power value specified before the amplitude of the external video signal increases. A projector for performing control to increase the lamp power. The projector according to claim 1 or 2,
When the lamp power is increased, the control unit sets an amplitude control time, which is a time for changing the amplitude of the video signal to an amplitude value specified according to the external video signal, and the lamp power according to the external video signal. A projector that generates the amplitude control signal that is shorter than a power control time, which is a time for changing to a specified power value. A control method for a projector, comprising: a lamp; and a display element that modulates light emitted from the lamp in accordance with an amplitude of a video signal corresponding to an external video signal given from outside and emits the light as video light. And
The control unit specifies a power value of lamp power for driving the lamp in accordance with the external video signal, generates a power control signal for gradually changing the lamp power to the specified power value, and the specified The amplitude value of the video signal in which the light quantity of the image light projected when the lamp power is changed to the power value is substantially the same as the light quantity of the video light when projected without changing the lamp power And generating an amplitude control signal that gradually changes the amplitude of the video signal to the specified amplitude value,
A lamp driving unit supplies lamp power corresponding to the power control signal generated by the control unit to the lamp,
An amplitude modulation unit adjusts the amplitude of the video signal in accordance with the amplitude control signal generated by the control unit, and drives the display element in accordance with the video signal in which the amplitude is adjusted,
When the control unit outputs the power control signal that decreases the lamp power when the amplitude of the external video signal decreases, increases the lamp power when the amplitude of the external video signal increases, and increases the lamp power Even if the amplitude of the external video signal decreases , the projector control method performs control to increase the lamp power until the power value specified before the amplitude of the external video signal decreases . The projector control method according to claim 4,
Wherein the control unit, wherein the the amplitude of the external video signal is increased when the lamp has a power and outputting the power control signal to reduce the, before the electric power value identified before the amplitude increases of the external video signal A control method for a projector, wherein control for increasing the lamp power is performed. In the control method of the projector of Claim 4 or 5,
When the control unit increases the lamp power, an amplitude control time, which is a time for changing the amplitude of the video signal to an amplitude value specified according to the external video signal, and the lamp power according to the external video signal A method for controlling a projector, wherein the amplitude control signal is generated to be shorter than a power control time, which is a time for changing to a specified power value.

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