JP2009109956A - Projector device and method for controlling luminance of its light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector device achieving reduction of parts cost by measuring luminance of a plurality of light sources by one photodetector 4. <P>SOLUTION: The projector device includes a light source driving part 1 calculating the luminance of each of the plurality of light sources and controlling the luminance, one photodetector 4 measuring the luminance of the plurality of light sources, a luminance measuring part 3 converting a signal from the photodetector 4 into luminance information, and a light source output characteristic storage part 2 storing the characteristic of the light source. Measurement and adjustment of the luminance of the light source are performed by one photodetector 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

    The present invention relates to a projector device that projects an image on a screen such as a liquid crystal projector.

  In the conventional projector apparatus, three light detection elements for detecting the luminance of the red, blue, and green light sources are provided in the paths of the respective light sources, so that the luminance balance of the target red, green, and blue light sources obtained in advance is obtained. The luminances of the red, green, and blue light sources are adjusted so that

By such control, it is possible to prevent luminance deterioration correction of the light source, white balance deviation correction, and color reproducibility deterioration.
JP 2005-208231 A

  In the conventional configuration, a light detection element for adjusting the luminance of the light source is required for each of the red, blue, and green light sources, which increases the component cost.

  Therefore, an object of the present invention is to provide a projector apparatus that can reduce the component cost by measuring the luminance of a plurality of light sources with a single light detection element.

In order to solve the conventional problem, the projector device of the present invention is
A video display unit;
For this video display unit, the video light conversion unit that synthesizes the irradiation light from the light source and the input video signal, converts the input video signal, and projects the video signal;
A plurality of light sources for inputting irradiation light to the image conversion unit;
A light source driving unit for calculating the brightness of each of the plurality of light sources and controlling the brightness;
One photodetecting element for measuring the luminance of the plurality of light sources;
It is comprised from the brightness | luminance measurement part which converts the signal from this photon detection element into brightness | luminance information.

  Thereby, the intended purpose can be achieved.

As described above, according to the invention described in claim 1,
In the process of projecting the video signal by synthesizing the input video signal with the irradiation light from multiple light sources and converting it to the video display unit,
The luminance of the plurality of light sources is measured by a single light detection element,
By calculating the luminance of each of the plurality of light sources and controlling the luminance, the component cost can be further reduced.

  Embodiments of a projector apparatus according to the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a functional block diagram showing the configuration of the projector apparatus according to the first embodiment of the present invention.
In contrast to the video display unit 300 configured with a screen or the like, the video conversion unit 200 synthesizes the irradiation light from the light source unit 100 and the input video signal S01 to convert it into a video signal, and projects the video signal.

In the light source unit 100 including a plurality of light sources that input irradiation light to the video conversion unit 200, the light source driving unit 1 that calculates the luminance of each of the plurality of light sources and controls the luminance,
One photodetecting element 4 for measuring the luminance of the plurality of light sources;
It is comprised from the brightness | luminance measurement part 3 which converts the signal from this photon detection element 4 into brightness | luminance information.

  With this configuration, the light source driving unit 1 performs adjustment so that the luminance of the plurality of light sources in the light source unit 100 becomes the target luminance. The luminance value of the target light source may be stored in advance in the light source output characteristic storage unit 2, may be set according to the input video signal S01, or may be set by the user of the projector device. good.

  Next, the configuration of the projector apparatus according to the first embodiment of the present invention will be described in more detail. FIG. 2 is a system configuration diagram showing the configuration of the projector apparatus according to the first, second, and third embodiments of the present invention.

  In FIG. 2, the luminance measurement unit 3 converts a conversion current S05 output from the light detection element 4 that converts incident light into a current, and outputs the converted current S05 as a measurement luminance S06 to the light source driving unit 1. The light source drive unit 1 receives the measured luminance S06 and the light source output characteristics S02 of the red, green, and blue light sources stored in the light source output characteristic storage unit 2, and emits red and red light sources 101R and green. The red light source driving current S03R, the green light source driving current S03G, and the blue light source driving current S03B, which are current values for driving the green light source 101G and the blue light source 101B that emit blue light, are output.

  Further, the light source drive unit 1 outputs the change information S04 to the light source output characteristic storage unit 2, so that the light source output characteristic storage unit 2 updates the light source output characteristic. The red light source shaping optical lens 102R shapes the light emitted by the red light source 101R, the green light source shaping optical lens 102G shapes the light emitted by the green light source 101G, and the blue light source shaping optical lens 102B is produced by the blue light source 101B. Shaping the light to irradiate. The red reflector 103 </ b> R reflects a part of the light shaped by the red light source shaping optical lens 102 </ b> R to the light detection element 4.

  The green reflector 103G reflects a part of the light shaped by the green light source shaping optical lens 102G to the light detection element 4. The blue reflector 103 </ b> B reflects a part of the light shaped by the blue light source shaping optical lens 102 </ b> B to the light detection element 4. The red incident reflection plate 104R reflects the shaped light that has not been reflected by the light detection element 4 in the red reflection plate 103R to the red spatial modulation element 201R.

  The blue incident reflection plate 104B reflects the shaped light that has not been reflected by the light detection element 4 in the blue reflection plate 103B to the spatial modulation element 201B. The spatial modulation element control unit 202 receives a red spatial modulation element control signal S07R, which is a control signal for the red spatial modulation element 201R, and a green, which is a control signal for the green spatial modulation element 201G, from an externally input video signal S01. A spatial modulation element control signal S07G for blue and a blue spatial modulation element control signal S07B which is a control signal for the blue spatial modulation element 201B are output. The combining optical lens 203 outputs the light modulated by the red spatial modulation element 201R, the green spatial modulation element 201G, and the blue spatial modulation element 201B as an output image S08. The output video S08 is projected onto the screen 302 through the projection optical lens 301.

  With such a configuration, the luminance of each of the plurality of light sources can be calculated by one photodetecting element 4 and can be produced at a lower component cost than a configuration using a plurality of photodetecting elements.

  Further, as an effect of the present invention, since the luminance of a plurality of light sources is measured by one photodetecting element 4, it is possible to perform measurement that is not affected by variations in the photodetecting elements as a measurement error.

A method for measuring the luminance of a plurality of light sources with one photodetecting element 4 will be described.
FIG. 3 shows a flowchart of a method for measuring the luminance of a plurality of light sources with one photodetecting element 4.

  First, in step 1, the luminances of a plurality of light sources are changed at different timings. For example, in the light source unit including the red light source 101R, the blue light source 101B, and the green light source 101G, for example, when it is desired to measure the current luminance of the red light source 101R, first, the red light source 101R, the blue light source 101B, and the green light source 101G are included. The luminance of the entire light source unit is measured by the light detecting element 4 (this luminance is set to L0), and then the luminance of only the red light source 101R is changed.

  In step 2, the brightness of a plurality of light sources is calculated from the amount of change in the brightness of the light source. This is the light detecting element 4 and measures the luminance after the red light source 101R changes. This is LGB.

  Here, the luminance of the light source and the characteristic of the set current are correlated, and the absolute value of the luminance of the light source with respect to the set current can be calculated by deriving the characteristic of the luminance with respect to the set current.

  As a method of deriving the luminance characteristics with respect to the set current, it may be derived by obtaining the amount of change in brightness, that is, the slope, with respect to the set current, assuming that both are in a proportional relationship, or several settings that take into account variations in the characteristics of the light source Several types of luminance value tables with respect to current may be provided for comparison.

  There may be a plurality of tables, and the tables may be updated by learning or newly added during video display.

  As a specific method of obtaining the luminance, the luminance change calculated by the difference of L0−LGB is LR1.

  This LR1 is defined as the amount of change in luminance with respect to the amount of change in set current, and selects which table characteristic the change in luminance belongs to the table of luminance values for the several set currents. To do.

  Based on the selected table, the characteristics of the setting current and the luminance in the red light source 101R are determined, and the absolute luminance with respect to the setting current of the red light source 101R can be calculated from the characteristics.

  In step 3, the calculated luminance of the light source is compared with the target luminance, and the luminance of the light source is adjusted so as to be the target luminance.

  By repeating the above procedure as many times as the number of light sources, it is possible to measure and adjust the luminance of the light sources with a single light detection element.

(Embodiment 2)
One method of measuring and adjusting the luminance of a light source in a projector apparatus is to set a white balance.

  Taking this white balance setting as an example, a method of creating a table of the relationship of luminance to the set current, and measurement of luminance and setting of white balance using the table will be described.

  The procedure for setting the white balance at startup will be described below.

  In the second embodiment, one frame of the input video signal S01 is composed of three colors of red, green, and blue. The red light source 101R, the green light source 101G, and the blue light source 101B are shown in FIGS. 4a, 4b, and 4c. The output characteristics of the current value and luminance value shown in FIG. Further, as shown in FIG. 5, the white balance is defined as a ratio of luminance values of red, green, and blue for each of a plurality of color temperatures, and current control is performed so that the luminance value becomes this ratio. White balance can be achieved.

  First, a description will be given of a method of creating a table of the relationship of the luminance with respect to the set current in the red light source 101R, the green light source 101G, and the blue light source 101B when the projector apparatus of the present invention is turned on.

  After the power is turned on, the light source driving unit 1 reads the ratio of red, green, and blue having a desired color temperature from the light source output characteristic unit 2 as the light source output characteristic S02. Here, the desired color temperature is a color temperature stored in the light source output characteristic storage unit 2.

  Next, the red light source driving current S03R of the red light source 101R is gradually increased, shaped by the red light source shaping optical lens 102R, reflected by the red reflecting plate 103R, and converted by the light detecting element 4. The current is converted into current S05 and output to the luminance measuring unit 3.

  The luminance measuring unit 3 outputs the conversion current S05 to the light source driving unit 1 as the measured luminance S06. At this time, the red light source driving current S03R and the measured luminance S06 are output to the light source output characteristic unit 2 as the change information S04. The light source output characteristic unit 2 updates the red light source current-luminance value table of FIG. 4A from the change information S04. This operation is repeated, and the red light source driving current S03R is increased until the measured luminance S06 reaches the target luminance. Here, the target luminance is the red luminance stored in the light source output characteristic storage unit 2.

  In this process, a table of the relationship of luminance with respect to the set current of the red light source 101R is created.

  Next, the green light source drive current S03G of the green light source 101G is gradually increased, shaped by the green light source shaping optical lens 102G, reflected by the green reflector 103G, and converted by the light detection element 4. The current is converted into current S05 and output to the luminance measuring unit 3. The luminance measuring unit 3 outputs the conversion current S05 to the light source driving unit 1 as the measured luminance S06. At this time, the green light source driving current S03G and the measured luminance S06 are output to the light source output characteristic unit 2 as the change information S04. The light source output characteristic unit 2 updates the green light source current-luminance value table of FIG. 4B from the change information S04. This operation is repeated, and the green light source driving current S03G is increased until the measured luminance S06 reaches the target luminance. Here, the target luminance is calculated by adding the red luminance and the green luminance stored in the light source output characteristic storage unit 2.

  In this process, a table of the relationship of the luminance with respect to the set current of the green light source 101G is created.

  Similarly, the blue light source drive current S03B of the blue light source 101B is gradually increased, shaped by the blue light source shaping optical lens 102B, reflected by the blue reflector 103B, and converted by the light detection element 4. The current is converted into current S05 and output to the luminance measuring unit 3. The luminance measuring unit 3 outputs the conversion current S05 to the light source driving unit 1 as the measured luminance S06. At this time, the blue light source driving current S03B and the measured luminance S06 are output to the light source output characteristic unit 2 as the change information S04. The light source output characteristic unit 2 updates the blue light source current-luminance value table of FIG. 4C from the change information S04. This operation is repeated, and the blue light source drive current S03B is increased until the measured luminance S06 reaches the target luminance. Here, the target luminance is calculated by adding the red luminance, the green luminance, and the blue luminance stored in the light source output characteristic storage unit 2.

  In this process, a table of the relationship of luminance with respect to the set current of the blue light source 101B is created.

  By the above procedure, it is possible to measure and adjust the luminance of the light source with a single light detection element during driving.

  Note that the configuration of the optical system described in this embodiment is merely an example, and the present invention is not limited thereto. Moreover, even if the order of colors is changed, the same method can be used. Further, the arrangement of the light sources can be realized by the same method even if they are exchanged.

  In addition, when the color temperature is changed by the operation of the viewer or the like, the white balance is not set again, but is set using the current-luminance value table created in the second embodiment, so that the white balance is instantaneously set. The balance can be changed.

(Embodiment 3)
In the projector apparatus, the brightness of the light source is increased by increasing the luminance of the light source with respect to the input video signal S01 of the bright video scene, and the brightness of the input video signal S01 of the dark video scene is decreased by decreasing the luminance of the light source. There is a control method called iris control as a method for increasing the contrast ratio and improving the sense of depth of an image.

  As an example of the present invention, in a projector apparatus using laser light sources of three colors of red, green, and blue, each light detection element 4 can control the brightness of red, green, and blue of the laser light source while performing the iris control. A method for measuring and controlling to the optimum luminance will be described.

  In the iris control, when a dark input video signal S01 is input, it is necessary to lower the laser light sources of three colors of red, green, and blue by the same ratio with respect to the maximum luminance. For example, when the ratio of reducing the luminance of the light source has to be reduced to 30% of the maximum luminance, all the light sources are not lowered at the same time, but are lowered separately one by one.

  For example, when lowering from the red light source 101R, first, the luminance of the entire current light source unit is measured from the light detecting element 4. This luminance is L0. Next, a red light source driving current S03R corresponding to a luminance of 30% is set, and the luminance of only the red light source is changed. This is LGB.

  Here, the luminance of the light source and the characteristic of the set current are correlated, and the absolute value of the luminance of the light source with respect to the set current can be calculated by deriving the characteristic of the luminance with respect to the set current.

  As a method of deriving the luminance characteristics with respect to the set current, it may be derived by obtaining the amount of change in brightness, that is, the slope, with respect to the set current, assuming that both are in a proportional relationship, or several settings that take into account variations in the characteristics of the light source Several types of luminance value tables with respect to current may be provided for comparison.

  There may be a plurality of tables, and the tables may be updated by learning or newly added during video display.

  As a specific method of obtaining the luminance, the luminance change calculated by the difference of L0−LGB is LR1.

  This LR1 is defined as the amount of change in luminance with respect to the amount of change in set current, and selects which table characteristic the change in luminance belongs to the table of luminance values for the several set currents. To do.

  Based on the selected table, the characteristics of the setting current and the luminance in the red light source 101R are determined, and the absolute luminance with respect to the setting current of the red light source 101R can be calculated from the characteristics.

  Next, the calculated luminance of the light source is compared with the target luminance, and the luminance of the light source is adjusted so as to be the target luminance.

  By performing the above procedure for the light sources of the green light source 101G and the blue light source 101B, it is possible to measure and adjust the luminance of the light source with a single light detection element 4.

  The target luminance corresponds to the luminance of the red light source 101R, the blue light source 101B, and the green light source 101G having a luminance ratio with respect to the target white balance.

  The laser light source can control the luminance by controlling the drive current, and the response speed of the luminance to the current can be a fast response on the order of several tens of microseconds.

  By using the above-described method, it is possible to perform iris control with an optimal white balance with a quick response that does not cause a sense of incongruity of video changes even when the viewer views the video.

  The projector device and the control method thereof according to the present invention are useful as a projector device in which the cost of parts is further reduced by adjusting a plurality of light sources with a single light detection element.

Functional block diagram of a projector apparatus in an embodiment of the present invention 1 is a system configuration diagram of a projector device according to an embodiment of the present invention. Flowchart of a method for measuring the luminance of a plurality of light sources in an embodiment of the present invention Red light source Current-luminance value table Green light source Current-luminance value table Blue light source Current-luminance value table Diagram showing color temperature ratio table

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source drive part 2 Light source output characteristic memory | storage part 3 Luminance measurement part 4 Photodetection element 100 Light source part 101R Red light source 101G Green light source 101B Blue light source 102R Red light source shaping optical lens 102G Green light source shaping optical lens 102B Blue light source shaping optics Lens 103R Red reflecting plate 103G Green reflecting plate 103B Blue reflecting plate 104R Red incident reflecting plate 104B Blue incident reflecting plate 200 Video conversion unit 201R Red spatial modulation element 201G Green spatial modulation element 201B Blue spatial modulation element 202 Spatial Modulation Element Control Unit 203 Synthetic Optical Lens 300 Image Display Unit 301 Projection Optical Lens 302 Screen S01 Input Video Signal S02 Light Source Output Characteristics S03R Red Light Source Drive Current S03G Green Light Source Drive Current S03B Blue Light Source Drive Current S04 Change Information S05 Conversion Current S06 Measurement Degree S07R red spatial modulation element control signal S07G green spatial modulation element control signal S07B blue spatial modulation element control signal S08 output video

Claims (4)

A video display unit;
For this video display unit, the video light conversion unit that synthesizes the irradiation light from the light source and the input video signal, converts the input video signal, and projects the video signal;
A plurality of light sources for inputting irradiation light to the image conversion unit;
A light source driving unit for calculating the brightness of each of the plurality of light sources and controlling the brightness;
One photodetecting element for measuring the luminance of the plurality of light sources;
A projector device comprising a luminance measuring unit that converts a signal from the light detection element into luminance information. The plurality of light sources are composed of a red light source, a green light source, and a blue light source whose brightness can be adjusted,
A light source output characteristic storage unit in which the luminances of the target red, green, and blue light sources are stored;
The light source drive unit separately changes the luminance of the red light source, the green light source, and the blue light source, and calculates the luminance of each of the red light source, the green light source, and the blue light source from the changed luminance, and the luminance is the light source. The brightness of the red light source, the green light source, and the blue light source is adjusted again so that the brightness of the target red, green, and blue light sources stored in the output characteristic storage unit is obtained. Projector device. A brightness control method for a light source of a projector device,
A first step of changing the luminance of the plurality of light sources at different timings;
A second step of calculating the luminance of a plurality of light sources from the amount of change in the luminance of the light source, using one photodetecting element;
And a third step of comparing the calculated luminance of the light source and the target luminance, and adjusting the luminance of the plurality of light sources so as to obtain the target luminance. Method. The brightness control method of the light source of the projector apparatus of Claim 3 with which the said 1st process, 2nd process, and 3rd process are performed at the time of iris control.

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