JP2007133094A - Projector and light adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector improved so that the white balance and the color reproducibility of a projected image can be freely adjusted, and utilized under any circumstances, and to provide a light adjusting method. <P>SOLUTION: In the projector 1 which projects the image by generating a plurality of color light beams in a time-division manner by using a color wheel (color generating means) 12 and projecting the generated light beams, a pulse current having a polarity, a level and time width corresponding to each color light beam is superposed on a DC current to be supplied to a light source 11 synchronizing with generating each of the plurality of color light beams. The emitted light quantity of the light source is changed, and the light quantity of each of the plurality of color light beams is changed. By changing the light quantities of the plurality of color light beams respectively, the white balance and the color reproducibility of the image are freely adjusted. By switching the combination of the light quantities of the plurality of color light beams in accordance with using circumstances such as circumstances where brightness is regarded as important or circumstances where the color reproducibility is regarded as important, the appropriate image in accordance with the circumstances is projected under any circumstances. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projector for projecting an image by generating a plurality of colors of light from white light from a light source in a time division manner and projecting the generated light, and a light adjustment method for adjusting light projected by the projector.

  In the field of presentation or video projection, a projector that projects an image onto an external screen or wall by projecting light to the outside is used. Such a projector forms an image based on image data on an image device such as a liquid crystal panel or DMD (Digital Micromirror Device), and projects light reflected or transmitted by the image device to the outside. An image on the image device is projected to the outside. As a method of projecting a color image by such a projector, there is a method of projecting a color image by projecting images of each color of R (red), G (green), and B (blue) in a time division manner.

  A projector that projects a color image in a time-sharing manner includes a disk-shaped color wheel that is divided into RGB color filters around a rotation axis, and allows light from a light source to pass through the rotating color wheel and light that has passed through the color wheel. Is projected onto the image device, and the image is projected by the light reflected by the image device or the light transmitted through the image device. The white light from the light source passes through the rotating color wheel and is applied to the image device, so that light of each color of RGB is applied to the image device in a time-sharing manner. The image device forms an image for each color in synchronization with the rotation of the color wheel, and the image of each color is projected in a time division manner. A user who views the image projected by the projector recognizes that the image of each color projected in time division is a color image.

The configuration of the color wheel provided in the projector is determined according to the specifications of the projector so that the brightness, color reproducibility, and white balance of the image projected by the projector are in a predetermined state. For example, the brightness of the image is improved by increasing the proportion of the G filter in the color wheel or adding a W filter that transmits white light into the color wheel. In addition, an ND (Neutral Density) G filter having a lower transmittance for transmitting the G light than the G filter is used in the color wheel. In addition, the number of color gradations is increased, and the color reproducibility of the image is improved particularly in a low luminance region. In Patent Document 1, a specific one of a plurality of filters included in a color filter is identified by superimposing a pulse on the current supplied to the light source in synchronization with the light from the light source being transmitted. A technique for improving the color reproducibility of an image by increasing the amount of light of each color is disclosed. In the field of projectors using an AC lamp as a light source, a technique for superimposing a pulse on an AC current supplied to a light source is disclosed in Patent Document 2, and an image can be obtained by increasing the amount of light of a specific color using this technique. Patent Document 3 discloses a technique for adjusting the gradation of the above.
JP 2004-212890 A Japanese National Patent Publication No. 10-501919 JP 2002-49097 A

  As described above, the brightness, color reproducibility, and white balance of the image projected by the projector are determined by the configuration of the color wheel, so it is difficult to arbitrarily adjust the state of the image according to the usage status of the projector. There is a problem that there is. In particular, there is a trade-off between image brightness and color reproducibility, so it can be used in both situations where brightness is important for presentations and other situations where importance is placed on color reproducibility such as video projection. It is difficult to realize a projector.

  Further, in a projector having a color wheel having an ND filter, an ordinary filter and an ND filter having a light transmittance lower than that of the filter, such as a G filter and an NDG filter, transmit light to be transmitted. Since the wavelengths do not exactly match, there is a problem that the white balance changes. Further, since it is necessary to create a color wheel to which an ND filter is added, there is a problem that the cost of the projector increases. Further, as the number of ND filters increases, the ratio of the boundary area between the filters in the color wheel increases. Of the light from the light source, the light that has passed through the boundary region between the filters cannot be used for image formation because the color is not separated. Therefore, there is a problem that the use efficiency of light from the light source deteriorates and the brightness of the image decreases due to an increase in the ratio of the boundary area between the filters.

  In the technique disclosed in Patent Document 1, since the light amount of a specific color is increased by superimposing a pulse on the current supplied to the light source, the ratio with the light amount of other colors is changed, and the white balance of the image is changed. Change. Therefore, it is necessary to superimpose pulses within a range where the white balance does not deteriorate, and there is a problem that the degree of freedom for adjusting an image is limited.

  The present invention has been made in view of such circumstances, and an object of the present invention is to change the amount of light of a plurality of colors that are repeatedly generated, thereby changing the white balance and color reproduction of a projected image. It is an object of the present invention to provide a projector that can freely adjust the characteristics.

  Another object of the present invention is to avoid the problems caused by the ND filter by realizing the same color reproducibility as when the ND filter is used without using the ND filter. It is to provide a projector.

  Still another object of the present invention is to adjust both brightness and color reproducibility by adjusting brightness and color reproducibility of an image to be projected according to usage conditions. Another object of the present invention is to provide a projector that can be used in the above situation and a light adjustment method for realizing the projector.

  The projector according to the present invention includes a light source that emits light with a light amount corresponding to the magnitude of a direct current supplied from a power supply, and a color that repeatedly generates a plurality of colors of light in a predetermined order from the light generated by the light source. In a projector comprising a generation unit and a unit that sequentially projects light of each color generated by the color generation unit, the color generation unit synchronizes with the generation of each of a plurality of colors of light. And a current control means for superimposing a pulse current having a predetermined polarity, magnitude and time width on the direct current corresponding to each of the above.

  In the projector according to the aspect of the invention, the current control unit may be a plurality of types of pulses having different sizes from each other in synchronization with the color generation unit repeatedly generating light of a specific color included in the plurality of colors of light. A means for superimposing each of the currents on the direct current in a predetermined order is provided.

  In the projector according to the aspect of the invention, the current control unit may generate each individual color generated by the color generation unit in synchronization with the color generation unit repeatedly generating light of a specific color included in the light of the plurality of colors. It has means for superimposing a pulse current having a time width shorter than the length of time that the light of the specific color lasts on the direct current.

  The projector according to the present invention includes a light source that emits light with a light amount corresponding to the magnitude of a direct current supplied from a power supply, and a color that repeatedly generates a plurality of colors of light in a predetermined order from the light generated by the light source. In a projector including a generating unit and a unit that sequentially projects light of each color generated by the color generating unit, a pulse superimposing unit that superimposes a pulse current on the direct current, and a specific color generated by the color generating unit Means for storing a plurality of types of correspondence relationships in which the light and the polarity, magnitude, and time width of the pulse current superimposed on the DC current by the pulse superimposing unit are stored; and the plurality of types of the correspondence relationships stored by the unit. The selection means for selecting one of the correspondence relationships from among the correspondence, and the correspondence selected by the selection means to the pulse superimposing means in synchronization with the light generation means generating light of a specific color. Engaged by characterized in that it comprises a means for superimposing the polarity associated with the particular color of light, a pulse current having a magnitude and duration to the DC current.

  In the projector according to the aspect of the invention, the correspondence relationship may be that any polarity of positive or negative polarity of the pulse current is associated with light of a specific color, and the pulse superimposing unit is the selection unit. According to one of the correspondences selected by the above, a pulse current having either positive or negative polarity can be superimposed on the direct current.

  The light adjustment method according to the present invention repeatedly generates light of a plurality of colors in a predetermined order from light generated by a light source that emits light with a light amount corresponding to the magnitude of a direct current supplied from a power supply, and sequentially projects the light. In the method of adjusting the light projected by the projector, the polarity, size, and time width that are predetermined in association with the light of the specific color are synchronized with the generation of the light of the specific color by the projector A correspondence relationship in which the specific color light and the polarity, the magnitude, and the time width of the pulse current are associated with each other is superimposed on the direct current with a plurality of types according to the usage status of the projector. It is characterized by switching from the corresponding relationship.

  In the present invention, a projector that repeatedly generates light of a plurality of colors such as RGB from light from a light source that emits white light with a light amount corresponding to the magnitude of a direct current, and projects an image using the generated light of each color In synchronism with the generation of each of the light of multiple colors, a direct current is generated by superimposing a pulse current having a polarity, magnitude, and time width corresponding to each color of light on the direct current to the light source. As a result, the amount of light emitted from the light source changes, and the amount of light of each of the plurality of colors changes.

  In the present invention, the projector generates a plurality of types of pulse currents having different sizes from each other in a predetermined order in synchronization with the repeated generation of light of a specific color included in the light of a plurality of colors. By superimposing on the current, light having the same color but different light amounts can be generated in a predetermined order. Accordingly, light having the same color and different light amounts can be projected in a time division manner, and the number of gradations of the color included in the image projected by the projector can be increased.

  In the present invention, the projector generates a pulse current having a time width shorter than the length of time for which the light of the specific color continues in synchronization with the generation of the light of the specific color included in the light of the plurality of colors. By superimposing on the direct current to the light source, light of the same color and different light amounts can be generated in a predetermined order, and the number of gradations of that color included in the image projected by the projector can be increased.

  In the present invention, the projector stores a plurality of types of correspondence between the light of each color to be generated and the polarity, magnitude, and time width of the pulse current, and the user's instruction or the like is selected from the plurality of types of correspondence. By selecting one correspondence with the above, and superimposing the pulse current according to the selected correspondence on the direct current to the light source in synchronization with the generation of light of each color, The correspondence relationship between the light and the polarity, magnitude and time width of the pulse current is switched. Accordingly, it is possible to switch the combination of the light amounts of a plurality of colors generated by the projector according to the usage status of the projector.

  Furthermore, in the present invention, the projector may superimpose a pulse current having an arbitrary polarity of positive or negative polarity on the direct current to the light source according to the correspondence between the light of each color to be generated and the polarity of the pulse current. Therefore, it is possible to more freely control the combination of the light amounts of the respective colors projected by the projector.

  In the present invention, the white balance is predetermined by changing the amount of light of one color by changing the amount of light of one color by changing the amount of light of each of the plurality of colors generated by the projector. The color reproducibility of the projected image can be adjusted by using the generated light of multiple colors while adjusting it so that it falls within the range, so that the white balance and color reproducibility of the projected image can be freely adjusted. It becomes possible.

  In the present invention, a plurality of types of pulse currents having different sizes or a pulse current having a time width shorter than the length of time for which light continues is superimposed on the direct current to the light source, so that the ND Without using a filter, it is possible to generate light of the same color and different amounts of light in a predetermined order. Therefore, an ND filter such as a change in white balance, an increase in the cost of a projector, and a deterioration in use efficiency of light emitted from a light source As in the case of using the ND filter, the color reproducibility can be improved by increasing the number of gradations of the image to be projected, while avoiding the problems caused by using the ND filter.

  In the present invention, the combination of the light amounts of a plurality of colors to be generated can be switched. Therefore, in a situation where importance is attached to the brightness of a presentation or the like, the light amount of each color is adjusted so that the image becomes bright, and the video is displayed. The brightness of the image, such as the situation in which it is projected, should be as bright as a movie theater, and a certain level of brightness is not necessary, but in situations where emphasis is placed on the color reproducibility of the image, the color reproduction of the image It is possible to project an appropriate image according to the situation, such as adjusting the amount of light of each color so as to improve the performance, including the situation where the brightness of the image is emphasized and the situation where the color reproducibility is emphasized A projector that can be used in any situation can be realized.

  Further, according to the present invention, it is possible to superimpose a pulse current having an arbitrary polarity of positive or negative polarity on a direct current to the light source according to the correspondence between the light of each color to be generated and the polarity of the pulse current. By doing so, it is possible to freely control the combination of the amount of light of each color projected by the projector, so the brightness, white balance and color reproducibility of the image projected by the projector can be freely adjusted according to the usage status of the projector The present invention has excellent effects, such as being able to be adjusted.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
FIG. 1 is a block diagram showing the internal configuration of the projector of the present invention. White arrows in the figure indicate light. The projector 1 includes a light source 11 using a DC lamp that emits white light, such as a halogen lamp, a metal halide lamp, or an ultrahigh pressure mercury lamp, a color wheel 12 that allows light from the light source 11 to pass through, and an image device 13 that forms an image. And a projection optical system 14 that projects light from the image device 13 to the outside. The light source 11 emits light when supplied with a direct current, and emits light with a light amount corresponding to the magnitude of the supplied direct current.

  The color wheel 12 is configured by arranging a plurality of filters each transmitting light of a specific color around the central axis of the disk, and a motor is directly connected to the central axis, for example, at a rotational speed of 60 Hz, the central axis Is configured to be rotated by a motor about the rotation axis. The color wheel 12 includes, for example, three color filters that allow each color of RGB to pass therethrough, and, for example, uses four color filters obtained by adding a W filter that passes white light to RGB. The projector 1 irradiates the rotating color wheel 12 with white light from the light source 11 by an optical system (not shown), and the white light sequentially passes through the filters of each color by the rotation of the color wheel 12, so that a plurality of colors such as RGB or RGBW are obtained. The light is repeatedly generated. In this way, the color wheel 12 functions as color generation means according to the present invention.

  The image device 13 is a planar device using a liquid crystal panel, DMD, or the like, and is configured to form an image for each color of RGB in a time division manner. The projection optical system 14 includes a prism, a projection lens, a mechanism for driving the projection lens, and the like. The projector 1 irradiates the image device 13 with light of each color that has passed through the color wheel 12 by an optical system (not shown), and the image device 13 forms an image corresponding to the light of the emitted color, and the image device that forms the image The light reflected on 13 is projected to the outside by the projection optical system 14. In this way, each color image is projected onto an external screen or wall in a time-sharing manner, and is recognized as a color image by the user. The projector 1 may be configured to pass the light from the color wheel 12 instead of reflecting it on the image device 13.

  The projector 1 also includes a control processing unit 25 including a processor that performs calculation, a ROM that stores information such as programs necessary for the calculation, and a RAM that stores temporarily generated information. The control processing unit 25 includes: A process for controlling the overall operation of the projector 1 is performed. The projector 1 also includes a color wheel control circuit 23 that performs processing related to the rotation of the color wheel 12 such as processing for detecting the rotational position of the color wheel 12 and processing for controlling the rotational speed of the color wheel 12. The circuit 23 is connected to the control processing unit 25. The image device 13 is connected to an image device control circuit 24 that performs processing for forming an image on the image device 13. The image device control circuit 24 is connected to a control processing unit 25. In addition, the control processing unit 25 receives a receiving unit 26 that receives image data transmitted from an external device such as a personal computer (PC) or a video reproduction device, and various processing instructions such as a hue switching instruction. An operation unit 27 that is received by operation is connected.

  The projector 1 further includes a power supply circuit 21 and a direct current ballast circuit 22 that supplies the current from the power supply circuit 21 to the light source 11 with a stable direct current, and the light source 11 is connected to the direct current ballast circuit 22 through a power line. The ballast circuit 22 is connected to the control processing unit 25 by a signal line. The DC ballast circuit 22 supplies a stabilized DC current to the light source 11, while generating a pulse current having an arbitrary polarity, magnitude, and time width according to control from the control processing unit 25, and generating the generated pulse current. In this configuration, it can be superimposed on a direct current supplied to the light source 11. The control processing unit 25 associates each of the light of a plurality of colors generated when the light from the light source passes through the color wheel 12 with the polarity, magnitude, and time width of the pulse current generated by the DC ballast circuit 22. I remember the information I put. Based on the stored information, the control processing unit 25 synchronizes the generation of light of a specific color with the DC ballast circuit 22 in the polarity and magnitude associated with the light of the specific color. In this configuration, a pulse current having a length and a time width is superimposed on a direct current to the light source 11. In this way, the DC ballast circuit 22 and the control processing unit 25 function as current control means according to the present invention. Since the light source 11 emits light with a light amount corresponding to the magnitude of the supplied direct current, for example, the direct current ballast circuit 22 applies a positive polarity pulse current to the light source 11 in synchronization with the generation of R light. When superimposed on the current, the magnitude of the direct current supplied to the light source 11 increases and the amount of R light increases.

  Next, the operation of the projector 1 of the present invention having the above configuration will be described. The control processing unit 25 receives the image data received by the receiving unit 26, and accepts an instruction to adjust the brightness, color reproducibility, or white balance of the image when the user operates the operation unit 27. The control processing unit 25 causes the color wheel control circuit 23 to rotate the color wheel 12, and the light from the light source 11 passes through one of the filters forming the color wheel 12, and light of a color corresponding to the passed filter is generated. Is done. The color wheel control circuit 23 detects the rotational position of which filter in the color wheel 12 is passing light. Further, the control processing unit 25 controls the operation of the DC ballast circuit 22 in accordance with the rotational position of the color wheel 12 detected by the color wheel control circuit 23, thereby storing the light in synchronism with the generation of light of each color. Based on this information, a pulse current having polarity, magnitude and time width associated with each color light is superimposed on the DC current to the light source 11 in the DC ballast circuit 22. In addition, the control processing unit 25 controls the operation of the image device control circuit 24 in accordance with the rotational position of the color wheel 12 detected by the color wheel control circuit 23, and in synchronization with the generation of light of each color, An image for each color based on the image data is formed in the image device 13 by time division. In this way, light of each color is irradiated onto the image device 13 in a time-division manner with a predetermined light amount, and the light reflected by the image device 13 that formed the image for each color is projected by the projection optical system 14 and is used for each color. The image is projected in time division.

  Next, the light adjustment method of the present invention will be described using an example of the correspondence relationship between the color of light generated by the projector 1 and the pulse current. FIG. 2 is a timing chart showing an example of control of the direct current supplied to the light source 11 when the color wheel 12 is composed of RGB filters. The horizontal axis in the figure is time, and FIG. 2A shows which color of light is generated by passing light from the light source 11 through any filter in the color wheel 12 at each time point. Shown in RGB. The length of the period in which the light of each color of RGB is generated is shown almost evenly in the drawing, but in reality, it is a length corresponding to the proportion of the filters of each color in the color wheel 12, Generally unequal. In this case, the color wheel 12 may have a configuration in which three colors of RGB filters are divided around the central axis, and six filters each including two filters for each color have six filters around the central axis. A divided configuration may be used. FIG. 2 (b) shows a direct current with no superimposed pulse current. In a state in which the DC ballast circuit 22 supplies a direct current as shown in FIG. 2B to the light source 11, the light source 11 emits white light with a substantially constant light amount, and the light of each color is defined by the configuration of the color wheel 12. It is generated with the amount of light.

  FIG.2 (c) shows the direct current which superimposed the pulse current in order to adjust the light of each color. In synchronism with the generation of G light by passing white light from the light source 11 through the G filter in the color wheel 12, a pulse current having a positive polarity and a predetermined magnitude is superimposed. Yes. Further, in synchronization with the generation of light of R color, a pulse current having a positive polarity and larger in magnitude than the pulse current of G color is superimposed. The control processing unit 25 stores information indicating the correspondence relationship between the light of each color and the polarity, magnitude, and time width of the pulse current, and the control processing unit 25 provides a light adjustment instruction by the operation of the user. 27, the operation of the DC ballast circuit 22 is controlled so that the pulse current in accordance with the correspondence indicated by the stored information is superimposed on the DC current to the light source 11. The direct current ballast circuit 22 superimposes a pulse current on the direct current supplied to the light source 11 according to the control of the control processing unit 25 so that the direct current as shown in FIG.

  As the direct current to the light source 11 increases in synchronization with the white light from the light source 11 passing through the G filter, the amount of light emitted from the light source 11 increases, and the amount of generated G color increases. To do. Similarly, the light quantity of the generated R color further increases than the light quantity of the G color. Since the light emission spectrum of the light source 11 normally used in the projector 1 has a small R wavelength component, the color reproducibility of the image is adjusted so that red can be reproduced better by increasing the light quantity of the R color. Can do. In the technique disclosed in Patent Document 1, since only the light quantity of R color is increased, the light quantity of R color protrudes and the white balance changes. In the present invention, by changing the amount of light of a plurality of colors such as R and G, the amount of light of each color can be adjusted to adjust the color reproducibility of the image and the white balance. That is, according to the present invention, the color of an image can be adjusted more freely than in the past while adjusting the amount of light of one color in accordance with the change of the amount of light of one color so that the white balance does not change significantly. It becomes possible to adjust the reproducibility. The control processing unit 25 stores information that defines the correspondence between the light of each color and the polarity, magnitude, and time width of the pulse current so that the white balance is within a predetermined range, and the control processing unit 25 performs direct current according to the stored information. By controlling the operation of the ballast circuit 22, the color reproducibility of the image is improved and the white balance is adjusted.

  Thus, in the present invention, in synchronization with the generation of light of a specific color, a pulse current having a predetermined polarity, magnitude, and time width is superimposed on the direct current supplied to the light source 11, The amount of light of a specific color changes. Thereby, the light quantity of each color changes from the light quantity prescribed | regulated by the structure of the color wheel 12, and the color reproducibility of the image which the projector 1 projects can be adjusted. In addition, the color reproducibility and white balance of the image projected by the projector 1 can be freely adjusted by superimposing a pulse current corresponding to each color on the direct current to the light source 11 in synchronization with the generation of light of multiple colors. can do.

  FIG. 2D shows a direct current in which a pulse current is superimposed to increase the number of gradations of the image projected by the projector 1. A pulse current is superimposed in synchronization with the generation of light of R color, and further, a pulse current is superimposed every other time in synchronization with the repeated generation of light of G color. Yes. Since the G light in which the pulse current is superimposed on the direct current supplied to the light source 11 and the G light in which the pulse current is not superimposed are alternately generated, the G light having a large light amount and the light amount are small. G light is generated alternately. When two types of light having different amounts of light are projected, even if the image is projected by forming the same image with the image device 13, the brightness of the projected image is different from each other. Therefore, by projecting light of the same color and different amounts of light in a time-sharing manner, the number of gradations of that color included in the image projected by the projector 1 can be increased. In the conventional technique, two types of G light having different light amounts are generated by adding an NDG filter in the color wheel 12, but in the present invention, the light of G color is generated repeatedly. Thus, by superimposing the pulse current every other time, two types of G light having different light amounts are generated in a time-sharing manner. That is, in the present invention, the number of gradations of the image projected by the projector 1 can be increased without using an NDG filter.

  Thus, in the present invention, in synchronization with repeatedly generating light of a specific color, a plurality of types of pulse currents having different sizes are superimposed on the direct current to the light source 11 in a predetermined order, Without using the ND filter, it is possible to generate light of the same color and different light amounts in a predetermined order. Therefore, in the present invention, the ND filter is used while avoiding problems caused by using the ND filter, such as a change in white balance, an increase in the cost of the projector 1, and a deterioration in the utilization efficiency of light emitted from the light source 11. Similarly to the case, the color reproducibility can be improved by increasing the number of gradations of the image projected by the projector 1.

  FIG. 2E shows another example of a direct current in which a pulse current is superimposed so as to increase the number of gradations of an image projected by the projector 1. In synchronization with the generation of the G color light, a pulse current having a time width shorter than the length of time that the G color light continues is superimposed. During the period in which the light of G color is generated, the amount of light is large while the pulse current is superimposed on the direct current supplied to the light source 11, and the amount of light is smaller while the pulse current is not superimposed. Become. Therefore, even when the pulse current is superimposed as shown in FIG. 2E, two types of G light having different light amounts are generated in a time-sharing manner, as in the case where the pulse current is superimposed as shown in FIG. In addition, the number of gradations of the image projected by the projector 1 can be increased without using an NDG filter. Thus, in synchronization with the generation of the light of the specific color, the pulse current having a time width shorter than the length of time that the light of the specific color continues is superimposed on the direct current to the light source 11. Without using an ND filter, it is possible to generate light of the same color and different light amounts in a predetermined order, and without using an ND filter, the number of gradations of an image projected by the projector 1 can be increased. Reproducibility can be improved. In the present invention, as described above, a plurality of types of pulse currents having different sizes or a pulse current having a time width shorter than the length of time during which light continues is superimposed on the direct current supplied to the light source 11. G light is the most effective light for changing the amount of light by the same method, but the color reproducibility of the image is improved by changing the amount of light using the same method for R or B light. A further improvement effect can be obtained.

  FIG. 3 is a timing chart showing a control example of the direct current supplied to the light source 11 when the color wheel 12 is composed of RGBW four-color filters. The horizontal axis in the figure is time, and W in FIG. 3A indicates that white light is generated by passing light from the light source 11 through a W filter that allows white light to pass through. By using such a color wheel 12, the projector 1 projects white light in a time division manner in addition to light of each color of RGB. FIG. 3B shows a direct current on which a pulse current is superimposed in order to improve the brightness of the image projected by the projector 1. A pulse current is superimposed in synchronism with the generation of light of G color, and further from the pulse current of G color with a positive polarity in synchronization with the generation of R color and white light. The pulse current having a large size is superimposed. Since the white light contains about three times the amount of light as compared to the light of each color of RGB, the brightness of the image projected by the projector 1 is projected by time-sharing the white light in addition to the light of each color of RGB. Will improve. By supplying a direct current as shown in FIG. 3B to the light source 11, the amount of white light increases, and the projector 1 can project an image with improved brightness.

  FIG. 3C shows a DC current on which a pulse current is superimposed in order to emphasize the color reproducibility of the image projected by the projector 1. A pulse current is superimposed on the direct current to the light source 11 in synchronization with the generation of light of R color, and the direct current to the light source 11 in synchronization with the generation of light of G color and white. The superposed pulse current is smaller in magnitude than the R-color pulse current. The white light transmitted by the W filter included in the color wheel 12 includes light of a color other than RGB that is light having an intermediate wavelength of the light transmitted by each of the RGB filters. Therefore, the color wheel including the W filter. When 12 is used, the brightness of the image is improved, but the color reproducibility of the image is deteriorated due to the mixture of light of colors other than RGB. Therefore, by supplying a direct current as shown in FIG. 3C to the light source 11, the brightness of the image projected by the projector 1 is reduced by increasing the light quantity of R and reducing the light quantity of white. Color reproducibility can be improved.

  The projector 1 of the present invention can switch the direct current supplied from the direct current ballast circuit 22 to the light source 11 between the direct current as shown in FIG. 3B and the direct current as shown in FIG. It has become a structure. That is, the control processing unit 25 stores a plurality of types of information indicating the correspondence between the generated light of each color and the polarity, magnitude, and time width of the pulse current, and instructs the light adjustment by the user's operation. When received by the operation unit 27, one information is selected from a plurality of types of information to be stored, and a pulse current according to the correspondence indicated by the selected information is superimposed on the direct current to the light source 11. The operation of the DC ballast circuit 22 is controlled. Thus, the DC ballast circuit 22 functions as a pulse superimposing unit according to the present invention, and the control processing unit 25 functions as a selecting unit according to the present invention.

  Thereby, the projector 1 supplies a direct current as shown in FIG. 3B to the light source 11 to improve the brightness of the image in a situation where the brightness is important such as a presentation, and reproduces a color such as a projected image. In a situation where importance is placed on the property, a direct current as shown in FIG. 3C can be supplied to the light source 11 to improve the color reproducibility of the image. Therefore, in the present invention, regardless of the configuration of the color wheel 12 included in the projector 1, any projector 1 including a situation where importance is given to brightness such as presentation and a situation where importance is attached to color reproducibility such as video projection. It is possible to realize the projector 1 that can project an appropriate image according to the situation even in the usage situation.

  FIG. 4 is a timing chart showing a control example of the direct current supplied to the light source 11 when the color wheel 12 includes a complementary color filter. The horizontal axis in the figure is time, and the YMC in FIG. 4A generates light of each color by passing light from the light source 11 through a complementary color filter that passes yellow, magenta, and cyan light, respectively. It is shown that. In the direct current shown in FIG. 4B, the pulse current is superimposed in synchronization with the generation of Y and M light, and is larger in synchronization with the generation of G, R, and C light. A pulse current having a large length is superimposed. In the direct current shown in FIG. 4C, the pulse current is superimposed in synchronization with the generation of B and G light, and the magnitude is increased in synchronization with the generation of Y, R, and C light. A pulse current having a large current is superimposed. By superimposing the pulse current on the direct current to the light source 11 in this way, the amount of light of each color changes, and even when the color wheel 12 including a complementary color filter is used, the white balance of the image projected by the projector 1 is predetermined. While adjusting to be within the range, the brightness and color reproducibility of the image can be adjusted according to the situation.

  In the present embodiment, when a pulse current is superimposed on a direct current supplied to the light source 11, a pulse current with a positive polarity is superimposed in synchronization with the generation of light of a color that should increase the amount of light. However, the projector 1 of the present invention is not limited to this. The light source 11 supplies a pulse current having a negative polarity in synchronization with the generation of light of a color whose light amount should be reduced. The form which performs the process superimposed on the direct current to the may be sufficient. Further, the projector 1 of the present invention superimposes a positive polarity pulse current on the direct current to the light source 11 in synchronism with the generation of light of one color, and generates light of other colors. In accordance with the information indicating the correspondence between the light of each color and the polarity of the pulse current so that a negative polarity pulse current is superimposed on the direct current to the light source 11 in synchronization, any polarity of positive or negative polarity The form which can perform the process which superimposes this pulse current on the direct current to the light source 11 may be sufficient. In the case of this form, it becomes possible to more freely control the combination of the light amounts of the respective colors projected by the projector 1, so that the brightness, white balance and image of the image projected by the projector 1 according to the usage status of the projector 1 can be controlled. Color reproducibility can be freely adjusted.

  In the present embodiment, the control processing unit 25 stores information in which each color light generated by the color wheel 12 is associated with the polarity, magnitude, and time width of the pulse current generated by the DC ballast circuit 22. However, the projector 1 of the present invention is not limited to this, and the DC ballast circuit 22 stores information in which the light of each color is associated with the polarity, magnitude, and time width of the pulse current. Form may be sufficient. In the case of this form, the DC ballast circuit 22 selects the correspondence between the light of each color and the pulse current according to the control by the control processing unit 25, and the pulse current according to the selected correspondence is converted to the DC current to the light source 11. Superimpose.

  Further, in the present embodiment, the projector 1 of the present invention has shown a form of a front projection system that projects an image onto an external screen or the like, but is not limited thereto, and includes a transmissive screen (not shown), A rear projection system may be employed in which an image is projected onto the screen by projecting light from the rear surface of the screen with the projection optical system 14.

It is a block diagram which shows the internal structure of the projector of this invention. It is a timing chart which shows the example of control of the direct current supplied to a light source when a color wheel consists of a filter of three colors of RGB. It is a timing chart which shows the example of control of the direct current supplied to a light source when a color wheel consists of four color filters of RGBW. It is a timing chart which shows the example of control of the direct current supplied to a light source when a color wheel contains a complementary color filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 11 Light source 12 Color wheel (color generation means)
DESCRIPTION OF SYMBOLS 13 Image device 14 Projection optical system 21 Power supply circuit 22 DC ballast circuit 23 Color wheel control circuit 24 Image device control circuit 25 Control processing part

Claims (6)

A light source that emits light with an amount of light corresponding to the magnitude of a direct current supplied from a power source, a color generation unit that repeatedly generates light of a plurality of colors in a predetermined order from the light generated by the light source, and the color generation And a projector that sequentially projects light of each color generated by the means,
In synchronization with the generation of each of the plurality of colors of light by the color generation means, a pulse current having a predetermined polarity, size, and time width corresponding to each of the plurality of colors of light is converted into the DC current. A projector characterized by comprising current control means for superimposing on the projector. The current control means synchronizes with the repeated generation of light of a specific color included in the light of the plurality of colors by the color generation means in a predetermined order for each of a plurality of types of pulse currents having different sizes. The projector according to claim 1, further comprising means for superimposing the direct current on the direct current. The current control unit is configured to output each of the specific color lights generated by the color generation unit in synchronization with the color generation unit repeatedly generating the specific color light included in the light of the plurality of colors. The projector according to claim 1, further comprising means for superimposing a pulse current having a time width shorter than a length of a continuous time on the direct current. A light source that emits light with an amount of light corresponding to the magnitude of a direct current supplied from a power source, a color generation unit that repeatedly generates light of a plurality of colors in a predetermined order from the light generated by the light source, and the color generation And a projector that sequentially projects light of each color generated by the means,
Pulse superimposing means for superimposing a pulse current on the DC current;
Means for storing a plurality of types of correspondences in which light of a specific color generated by the color generation unit and the polarity, magnitude, and time width of the pulse current superimposed on the direct current by the pulse superimposing unit are associated with each other;
Selecting means for selecting one of the correspondence relationships from the plurality of types of correspondence relationships stored by the means;
In synchronization with the generation of light of a specific color by the color generation means, the polarity and magnitude associated with the light of the specific color according to the correspondence selected by the selection means to the pulse superimposing means. And a means for superimposing a pulse current having a time width on the direct current. In the correspondence, the polarity of the pulse current is associated with light of a specific color with an arbitrary polarity of positive or negative polarity,
The pulse superimposing means is configured to superimpose a pulse current having either positive or negative polarity on the direct current according to one of the correspondences selected by the selecting means. The projector according to claim 4. Adjusts light projected by a projector that repeatedly generates and projects light of a plurality of colors in a predetermined order from light generated by a light source that emits light in accordance with the magnitude of a direct current supplied from a power supply. In the method
In synchronization with the generation of light of a specific color by the projector, a pulse current having a predetermined polarity, magnitude and time width corresponding to the light of the specific color is superimposed on the direct current,
The correspondence relationship that associates the light of the specific color with the polarity, magnitude, and time width of the pulse current is switched from among a plurality of types of correspondence according to the use status of the projector. Adjustment method.

Images