JP5144029B2 - Spatial light modulation system, driving method thereof and projector - Google Patents

Description

  The present invention relates to a spatial light modulation system, that is, a spatial light modulation device such as DMD (Digital Micromirror Device: trademark of Texas Instruments Inc., USA) and the like, and the spatial light modulation device for performing light modulation. The present invention relates to a system including a light source that emits light and a control circuit that controls the light source, and a driving method thereof. The present invention also relates to a projector incorporating the spatial light modulation system according to the present invention as described above, and further to a projector employing the method for driving the spatial light modulation system according to the present invention.

  In the field of presentation or video projection, it is installed in a front projection type projector that projects an image represented by an image signal input from a computer or various video playback devices onto an external screen or the like, or in a box-shaped housing. A DLP (Digital Light Processing: trademark (hereinafter abbreviated as US) Texas Instruments) system such as a rear projector TV that projects an image from a projector to a screen provided on one side of a housing is used. Such a DLP system generates modulated light representing an image obtained by modulating light emitted from a light source based on an image signal by providing an image signal as digital data to a spatial light modulator, specifically a DMD or the like. The generated modulated light is projected onto the screen.

  By the way, in the DLP system as described above, conventionally, light of each color of R (red), B (blue), G (green) and sometimes white light is time-divided into one plate-like spatial light modulator. In general, a color image is projected by projecting with R, and in general, light of each color R (red), B (blue), and G (green) is projected to each of the three spatial light modulators. There exists a method of projecting a color image by generating modulated light and combining them.

  The former method is generally called a single plate method. In this single-plate method, the light source emits light by rotating a color wheel in which filter segments that transmit each chromatic (R, B, G) light and, in some cases, white light are arranged in the circumferential direction. The light (white light) is separated into each chromatic color and, in some cases, white, and is given to the spatial light modulator in a time-sharing manner.

  By the way, in the above-described single-plate DLP system, filter segments that transmit light of three colors or four colors are arranged on a color wheel, and a modulation period (a component of each color of an image signal is separated) by a spatial light modulator. Thus, it is necessary to rotate each of them in synchronization with the period given to the spatial light modulator. In such a conventional single-plate DLP system, a phenomenon called color separation and color break-up, which degrades image quality, is known.

  Color separation means that images of the three primary colors R, B, and G are separated and viewed when the observer's line of sight moves on an image projected from a single-plate DLP system as described above onto a screen or the like. It is a phenomenon. On the other hand, color breakup is a phenomenon in which images of three primary colors are separated and visually recognized by an observer when a moving image is projected onto a screen or the like. In either case, it is possible to reduce the color wheel by increasing the number of color divisions or increasing the number of rotations. However, in order to do so, it is necessary to improve the accuracy of the color wheel rotation system, improve the frequency of image display, and the like, which causes an increase in cost. Such a problem is not a problem that does not occur because a color wheel is not used in a method that is not a single plate method as described above, for example, a three plate method. However, the three-plate system has a relatively large overall structure and is complicated, and therefore has to be expensive. For this reason, some improvement measures are required even in a single-plate system having a relatively simple configuration and a small size.

  Under such circumstances, for example, Patent Document 1 discloses an invention of a spatial light modulation system that does not use a color wheel even though it is a single plate system. In the invention disclosed in Patent Document 1, the LEDs of the three primary colors are caused to emit light sequentially, so that the number of color divisions of the color wheel described above is increased or the number of rotations is increased. Similar effects are obtained.

  FIG. 7 is a timing chart showing the display timing of each color for one frame of an image signal in a single-plate DLP system using a conventional general color wheel. In this example, the period of one frame shown in FIG. 7A is a display period for sequentially displaying R, B, and G colors as shown in FIGS. 7B, 7C, and 7D, respectively. (Subframes SFR, SFB, SFG) are divided into three equal parts, and within the periods of the subframes SFR, SFB, SFG for the respective colors as shown in FIGS. 7 (e), (f), (g). The rotation of the color wheel is synchronized so that the light from the light source is transmitted through the filter segment of each color (R, B, G) corresponding to the color wheel. Therefore, as shown in FIG. 7 (h), an image obtained by decomposing the image signal into R, B, and G color components is displayed in each color in each subframe between one frame of the image signal. In the human eye, images of each color of R, B, and G in the same frame of the image signal are visually recognized in one frame period, and these are visually recognized as color images by the afterimage phenomenon.

  On the other hand, FIG. 8 is a timing chart simply showing the display timing of each color of the invention disclosed in Patent Document 1 which is the prior art. In the invention disclosed in Patent Document 1, the period of one frame of the image signal shown in FIG. 8 (a) is divided into eight subframes SF1 to SF8, and R, B, G in each subframe. Each color component is displayed. Specifically, the first display period of the R component shown in FIG. 8B is the first display period of the B component as shown in FIG. 8C, and the next is the display of FIG. ) Is the first display period of the G component. The first sub-frame SF1 is constituted by the first display periods of these R, B, and G colors. Then, the first display period of the last G component of the first subframe SF1 is followed by the second subframe SF2, the first of which is the second display period of the R component, and the second is the second display period of the B component. 2 is the second display period, and the next is the second display period of the G component. Hereinafter, in each of the subframes SF3 to SF8, there are display periods for the colors R, B, and G, respectively.

  On the other hand, as shown in FIGS. 8E to 8G, the light emission periods of the respective colors are synchronized in the display periods of the R, B, and G colors of the subframes SF1 to SF8. The light emission times of these colors are very short compared to the prior art using the color wheel shown in FIG. 7 and very frequently. However, as described above, the light emission times of the colors R, B, and G are as follows. This can be realized by the light speed response of the LED as a light source for emitting light.

  Therefore, in the timing chart in the case of the prior art using the color wheel shown in FIG. 7, the display period of each color is once in one frame period. Then, as shown in FIG. 8 (h), each is dispersed eight times. Therefore, in the invention disclosed in Patent Document 1, it is possible to obtain substantially the same effect as when the color wheel is rotated at a high speed, so that the possibility of occurrence of color separation and color breakup is reduced. The In addition, the invention disclosed in Patent Document 1 does not use a color wheel that is rotationally driven, so that vibration, noise, and the like are not generated, and a white light lamp that generates high heat is not used as a light source. Is also advantageous.

  By the way, in the conventional DLP system, in order to express the gradation of the color, the time during which the spatial light modulator actually reflects the light of the color while the light of each color is irradiated on the spatial light modulator. Processing to adjust the length was performed. For example, in order to simplify the explanation, when considering a case where gradation is expressed by 2 bits, the time corresponding to the second bit is set to half of the time corresponding to the first bit. As a result, when the time corresponding to the first bit is “1”, the combinations of the first bit and the second bit are “0”, “0.5”, “1.0”, “1.5”. 4 times can be set, so that four gradations can be expressed.

  In a normal DLP system, the gradation of each color is generally controlled by 8 bits, and the display time is shortened by half in the order from the 1st bit to the 8th bit, or conversely by 2 times. Therefore, 256 gradations can be expressed. On the other hand, since the spatial light modulation device is turned on / off by the digital data corresponding to the element that displays each pixel, the input image data and the brightness (intensity) of the modulated light are simply controlled when gradation control is performed. Although the relationship of corresponds to a straight line, a so-called gamma curve cannot be expressed. This is because, in order to express the gamma curve, it is necessary to change the brightness of the modulated light more finely in the low gradation part, but for this purpose, the number of gradations is insufficient in 256 gradations.

  In order to cope with such a shortage of the number of gradations, conventionally, image processing is performed before giving data to the spatial light modulator, for example, using a technique called area gradation which is a kind of so-called error dispersion method. It corresponded. For example, when there is a region in which four pixels of the same color are gathered in a matrix, for example, only two of the pixels are displayed (turned on), thereby increasing the brightness of the entire four pixels. This is a technique of reducing the gradation value to 1/2, in other words, converting the gradation value to 1/2. In this case, when the display pixel is fixed, two of the four pixels are displayed as black dots continuously. For example, by changing the display pixel at every display cycle at random. Prevent black spots from being identified. However, since any two of the four pixels that should be displayed in the same color are not displayed, noise that flickers the image is mixed.

In FIG. 8, the display periods of eight times for each of the colors R, B, and G are shown as the same length, but in actuality, eight times for each color in order to perform gradation expression as described above. The length of the display period is different. Specifically, as shown in the timing chart of FIG. 9, when the time of each of the first display periods R1, B1, G1 of R, B, G is “1”, the second of R, B, G Each of the display periods R2, B2, and G2 is “½”, and is shortened to “1/4”, “1/8”, and so on. In the invention described in the cited document 1, gradation expression can be performed in this way (in contrast to the above-described example, the gradation may be increased by a factor of two).
JP 2005-25160 A

  However, since the invention described in Patent Document 1 can obtain substantially the same effect as when the color wheel is rotated at a high speed, a phenomenon called color separation and color breakup occurs. It may be effective as a countermeasure against doing. However, when the display state is low gradation, noise due to the error diffusion method is conspicuous, and there is a problem that display quality is deteriorated.

  The present invention has been made in view of the circumstances as described above, and the occurrence of phenomena called color separation and color breakup, which existed in a conventional DLP system using a color wheel in a single plate system, has been made. The main object of the present invention is to provide a spatial light modulation system and a driving method thereof that can reduce the occurrence of noise caused by the error diffusion method that is conspicuous when the display state is low gradation. The present invention also relates to a projector incorporating the spatial light modulation system as described above, and further to a projector employing a driving method of the spatial light modulation system.

The spatial light modulation system according to the present invention includes a plurality of light sources that emit light of different chromatic colors, and an image signal corresponding to the chromatic light emitted by the plurality of light sources, respectively. In addition, the period of one frame of the image signal is divided into a plurality of periods in which the display time sequentially changes for each of the plurality of chromatic colors, and each subframe is displayed. A spatial light modulator that controls whether or not to express the gradation of each chromatic color component, and a plurality of chromatic color components corresponding to the chromatic color light emitted by each of the plurality of light sources The spatial light modulation device control means for separating and supplying the spatial light modulation device to the spatial light modulation device, the timing at which the spatial light modulation device converts the image signal into modulated light respectively representing a plurality of chromatic color components, and the plurality of light sources Have In the spatial light modulation system comprising a light source control means to synchronize the timing of emission colors of light, the light source control means includes a storage means for storing data that defines a different value depending on each sub-frame, sub Pulse signal generating means for generating a pulse signal having a cycle shorter than each period of the frame and having a duty ratio corresponding to the data stored in the storage means, and pulses generated by the pulse signal generating means characterized Rukoto and a driving means for emitting the light of the chromatic color in each of the light source in accordance with the duty ratio of the signal.

In such a spatial light modulation system according to the present invention, when displaying an image component of a color corresponding to chromatic light emitted from each light source, the light emission period of the corresponding color changes.
In addition , each light source emits chromatic color light according to the duty ratio of the pulse signal having a duty ratio corresponding to data set to a different value according to the subframe obtained by dividing one frame of the image signal into a plurality of subframes.

Furthermore, the spatial light modulation system according to the present invention is the above-described spatial light modulation system invention, wherein the light source emits chromatic light emitted from each of the light sources, and the light sources according to the detection results of the detection means. The light source control means further comprises correction means for generating correction data for changing the light emission period of the chromatic light emitted from each of the light sources, and correction data storage means for storing the correction data generated by the correction means. , Data correction means for correcting the data stored in the storage means with correction data stored in the correction data storage means , and the pulse signal generation means corresponds to the data corrected by the data correction means. A pulse signal having a duty ratio and having a cycle shorter than the period of the subframe is generated, and the driving means is configured such that the pulse signal generating means Wherein the chromatography data correcting means are so as to emit light chromatic respectively the light sources in accordance with the duty ratio of the pulse signal generated in response to the correction data.

  In such a spatial light modulation system according to the present invention, in the invention of the spatial light modulation system, correction data for changing the light emission period of chromatic light emitted by each light source according to the detection result by the detection means Is generated. Then, a pulse signal having a duty ratio corresponding to the data corrected by the correction data is generated, and each light source emits chromatic light according to the duty ratio of the pulse signal.

  Furthermore, the spatial light modulation system according to the present invention is the spatial light modulation system according to any one of the above spatial light modulation systems, wherein the plurality of chromatic colors are red, blue, and green, and the light source control means emits light of each color. The light source is configured to emit white light or light of any color of cyan, magenta, and yellow by selectively emitting all or any two of the light sources.

  In such a spatial light modulation system according to the present invention, in any one of the spatial light modulation system inventions described above, white light, cyan, magenta, or yellow can be obtained by a combination of light sources that emit red, blue, and green light. Emits light of any color.

The spatial light modulation system driving method according to the present invention includes a plurality of light sources that respectively emit light of different chromatic colors, and a plurality of chromatic colors corresponding to the chromatic light that the plurality of light sources emit respectively. converts the modulated light representing the components, the period of one frame of images signals, the plurality of chromatic color separately, and each subframe is divided into a plurality of periods in which the display time is changed sequentially, each sub-frame In the method of driving a spatial light modulation system comprising a spatial light modulation device that expresses the gradation of each chromatic color component depending on whether or not the display is performed, the sub-frame displays different colors with the same display time. The period is continuous, and the light source of the corresponding color in the plurality of light sources is synchronized with the display period of each color included in each subframe , and has a cycle shorter than each period of the subframe. , each And characterized in that light by a pulse signal of different duty ratios corresponding to the subframe.

  In such a driving method of the spatial light modulation system according to the present invention, images of each color separated into a plurality of chromatic colors are displayed a plurality of times during one frame of the image signal, and the light emission period of the light source is set in each of them. Since it can be changed, it is possible to display an image with a finer gradation than in the past.

The spatial light modulation system driving method according to the present invention is the above-described spatial light modulation system driving method invention, wherein a duty ratio of a pulse signal for causing the plurality of light sources to emit light corresponding to the length of display time of a subframe is set. It is characterized by adjusting the size .

  In such a spatial light modulation system according to the present invention, in the above-described spatial light modulation system invention, when the display time is long, the duty ratio of the pulse signal for causing the light source to emit is increased, and conversely, the display time is short. Since the duty ratio of the pulse signal for causing the light source to emit is reduced, the contrast of the image is increased.

  Furthermore, the spatial light modulation system driving method according to the present invention is the above-described spatial light modulation system driving method invention, wherein the duty cycle of the pulse signal for causing the plurality of light sources to emit light is directly proportional to the display time length of each subframe. It is characterized by different ratios.

  In such a spatial light modulation system according to the present invention, in the invention of the spatial light modulation system described above, when the display time is long, it becomes possible to increase the duty ratio of the pulse signal for causing the light source to emit light. When the display time is short, the duty ratio of the pulse signal for causing the light source to emit light can be reduced.

  The spatial light modulation system driving method according to the present invention is any one of the above-described spatial light modulation system driving methods, wherein the chromatic color light emitted from each of the light sources is detected by a detection means, A duty ratio of a pulse signal for causing the plurality of light sources to emit light is changed according to a difference between a detection result by the detection means and a predetermined value.

  In such a spatial light modulation system according to the present invention, in any one of the spatial light modulation system inventions described above, a pulse signal for causing a plurality of light sources to emit light according to a difference between a detection result by the detection means and a predetermined value. The duty ratio is changed.

  Furthermore, the driving method of the spatial light modulation system according to the present invention is any one of the above-described driving methods of the spatial light modulation system, wherein the plurality of chromatic colors are red, blue and green, and all of the light sources Alternatively, white light or light of any color of cyan, magenta, and yellow is emitted by selectively emitting any two of them.

  In such a spatial light modulation system according to the present invention, in any one of the spatial light modulation system inventions described above, white light or cyan, magenta, and yellow light can be obtained by combining light sources that emit red, blue, and green light. It becomes possible to emit light of any color.

  Furthermore, a projector according to the present invention includes any one of the spatial light modulation systems described above and a projection lens that projects the modulated light converted by the spatial light modulation device.

  In such a projector according to the present invention, a projector having the characteristics of any one of the spatial light modulation systems described above is realized.

  Still further, a projector according to the present invention is a projector including a spatial light modulation system and a projection lens that projects the modulated light converted by the spatial light modulation device, and the spatial light modulation system is any one of the above. It is driven by the driving method of one spatial light modulation system.

  In such a projector according to the present invention, a projector having the characteristics of the driving method of any one of the spatial light modulation systems described above is realized.

  According to the spatial light modulation system according to the present invention as described above, when displaying an image component of a color corresponding to chromatic light emitted by each light source, the display time of each color and the light emission period of the corresponding color light source Since the brightness of the image can be adjusted by combining with the above, it becomes possible to express a finer gradation and to easily express a so-called gamma curve.

  Also, according to the spatial light modulation system of the present invention, in the above spatial light modulation system invention, pulses of a duty ratio corresponding to data set to different values according to subframes obtained by dividing one frame of an image signal into a plurality of subframes Each light source emits chromatic light according to the duty ratio of the signal, so power consumption is reduced compared to changing the length of the image display period while maintaining the light source at a constant emission intensity It becomes possible to do.

  Further, according to the spatial light modulation system of the present invention, in the spatial light modulation system invention, correction data for changing the light emission period of the chromatic light emitted from each light source according to the detection result by the detection means. Therefore, strict adjustment during manufacture is not necessary, and it is possible to compensate for aging of the LED.

  Furthermore, according to the spatial light modulation system according to the present invention, in any one of the spatial light modulation system inventions described above, only white light or cyan, magenta, Since it is possible to cope with the case where light of any color of yellow is required, it is possible to cope with an application in which the luminance of an image called a so-called data projector is given priority only by light emission control of the light source. At the same time, it becomes possible to easily perform finer color expression using intermediate colors such as cyan, magenta, and yellow.

  According to the driving method of the spatial light modulation system according to the present invention as described above, an image of each color separated into a plurality of chromatic colors is displayed a plurality of times during one frame of the image signal, and each of the light sources of the light source is displayed. Since the light emission period can be changed, the brightness of the image can be adjusted by a combination of the display time of each color and the light emission period of the corresponding color light source. A so-called gamma curve can be easily expressed.

  Further, according to the method for driving a spatial light modulation system according to the present invention, in the above-described invention for the method for driving a spatial light modulation system, when the display time is long, the light emission period of the light source becomes long, and conversely, the display time is short. Since the light emission period of the light source is shortened, an image with higher contrast can be displayed.

  Furthermore, according to the method for driving a spatial light modulation system according to the present invention, in the invention for the method for driving a spatial light modulation system, the gradation can be lowered more particularly in the low gradation portion of the image. It is possible to express a gamma curve without performing image processing.

  Furthermore, according to the method for driving a spatial light modulation system according to the present invention, correction data for changing the light emission period of chromatic light emitted from each light source is generated in the invention for the method for driving a spatial light modulation system. Therefore, strict adjustment at the time of manufacture becomes unnecessary, and it becomes possible to compensate for aging of the LED.

  Furthermore, according to the method for driving a spatial light modulation system according to the present invention, in any one of the inventions for the method for driving a spatial light modulation system described above, only a light source that emits R, B, and G light is used. Since light or cyan, magenta, or yellow light is necessary, it is possible to cope with light source light emission control only in applications where priority is given to image brightness, so-called data projectors. In addition, it is possible to easily perform finer color expression using intermediate colors such as cyan, magenta, and yellow.

  Furthermore, according to the projector of the present invention, the brightness of the image can be adjusted by a combination of the display time of each color and the light emission period of the corresponding color light source. A curve can be easily expressed. In addition, it is possible to deal with an application in which the luminance of an image called a so-called data projector is given priority only by controlling the light emission period, and further using intermediate colors such as cyan, magenta, and yellow. It is also possible to express finer colors easily, and it is possible to reduce power consumption compared to changing the length of the image display period while maintaining the light source at a constant light emission intensity. Become.

  Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof. FIG. 1 is a schematic diagram showing a configuration example of a main part when an embodiment of a spatial light modulation system according to the present invention is incorporated in a projector as an example of a DLP system.

  A projector incorporating a spatial light modulation system according to the present invention decomposes each frame of an image signal to be displayed inputted from the outside into components of a plurality of chromatic colors, for example, R, B, G (red, blue, green). Then, the DMD driving circuit 11 for generating the image data signal DS for each chromatic color, and the reflection angles of a number of micromirrors are controlled according to the image data signal DS for each chromatic color generated by the DMD driving circuit 11 in units of frames. (On / off) DMD 12 as a spatial light modulation device that modulates projection light for each chromatic color from the LED circuit 15 to be described later and modulates the projection light into an image for each chromatic color And a projection lens 13 for projecting modulated light for each chromatic color, which is spatially modulated by the DMD 12, onto an external screen or the like.

  The modulated light for each chromatic color projected from the projection lens 13 to an external screen or the like in a time-sharing manner is synthesized by the afterimage effect by the human eye and recognized as a color image.

  Further, the projector incorporating the spatial light modulation system according to the present invention controls the light emission timings of the three colors R, B, and G in synchronization with the image data for each chromatic color generated by the DMD driving circuit 11. The LED drive circuit 14, the LED circuit 15 that emits light of three colors of R, B, and G controlled by the LED drive circuit 14, and the three colors of light of R, B, and G emitted from the LED circuit 15 And an optical system 16 for projecting to the DMD 12. The LED drive circuit 14 has an LED control signal LEDCS for controlling the light emission timing of the LED for each chromatic color in synchronization with the image data of each chromatic color generated by the DMD drive circuit 11. It is given from the drive circuit 11. As will be described in detail later, the LED control signal LEDCS given from the DMD driving circuit 11 to the LED driving circuit 14 is specified by a subframe signal SFS for specifying each subframe within one frame period and the subframe signal SFS. And a subframe period signal SFPS for specifying a period during which light of each color of R, B, and G within each subframe period is to be emitted. Therefore, the sub-frame period signal SFPS includes an R-light subframe period signal RSFPS that specifies a period in which R light should be emitted, and a B-light subframe period signal BSFPS that specifies a period in which B light should be emitted. And a G light subframe period signal GSFPS for specifying a period during which the G light should be emitted.

  The spatial light modulation system according to the present invention can be applied to a so-called front projection method for projecting an image to an external screen or the like, and a rear projection method for projecting from the back of the screen. The present invention can also be applied to an application in which an image is directly displayed on a liquid crystal panel as a spatial light modulator. In the present embodiment, the DMD 12 is provided as a spatial light modulation device, but other types of spatial light modulation devices such as a liquid crystal panel can be used as long as they can respond at high speed.

  The optical system 16 includes appropriate lenses, rod integrators, reflectors, and the like for projecting light of three colors R, B, and G emitted from the LED circuit 15 to the DMD 12, but is known per se. Since it is a technique, detailed description is omitted. The projection lens 13 is also generally composed of a plurality of lenses, and includes a focus adjustment mechanism, a zoom mechanism, and the like. However, since this is a known technique, a detailed description thereof will be omitted. Further, when white light is used in addition to light of the three colors R, B, and G, white light is emitted by simultaneously emitting light of the three colors R, B, and G in the LED circuit 15. However, it is also possible to emit light of intermediate colors of cyan, magenta, and yellow by selectively emitting any two colors simultaneously.

  FIG. 2 is a block diagram showing the configuration of the LED circuit 15 and the LED drive circuit 14. In FIG. 1, the LED circuit 15 and the LED drive circuit 14 are shown as separated components for convenience, but both are integrally configured as shown in FIG. 2. The LED driving circuit 14 and the LED circuit 15 include individual circuits for light of each color of R, B, and G. Since each of them has the same configuration, a circuit for R light will be described below as an example. .

  The circuit for R light is configured by connecting in parallel a plurality of R light emitting circuits that individually emit red light (R light). The R light emitted from each R light emitting circuit travels on the same optical axis in the direction of the R light collective reflector 15MR to become combined R light. Specifically, the LED 152R that emits red light (R light), the reflecting mirror 151R that reflects the R light emitted by the LED 152R in the direction of the R light collecting reflector 15MR, and the on / off of the LED 152R are controlled. The switch 153R constitutes a set of R light emitting circuit. The control terminal of the switch 153R of each R light emitting circuit is connected to the R light drive circuit 14R. Also, one end of the LED 152R of each R light emitting circuit is connected to the R light power supply 150R, and the other end is connected to the ground terminal via each switch 153R.

  Therefore, when the R light drive circuit 14R outputs an ON signal and is input to the control terminal of each switch 153R, each LED 152R connected to each switch 153R has one end to the R light power supply 150R and the other end to the other. Each LED 152R emits R light because it is connected to the ground terminal. In the following, in each of the R light emitting circuits, the side closer to the collective reflecting mirror 15MR is referred to as the downstream side, and the far side is referred to as the upstream side.

  Each reflecting mirror 151R reflects the R light emitted by the LED 152R of the R light emitting circuit to which the reflecting mirror 151R belongs in the direction of the R reflecting collective mirror 15MR, and linearly transmits the R light emitted by the upstream LED 152R. Is used. Therefore, the R light emitted by each LED 152R is reflected on the same optical axis by the reflecting mirror 151R of the respective R light emitting circuit in the direction of the R light collecting reflector 15MR, and at the downstream side, the reflecting mirror 151R of the R light emitting circuit. However, on the extension of this optical axis, a collective reflecting mirror 15MR for R light is provided. Accordingly, each LED 152R of the plurality of R light emitting circuits included in the R light circuit emits light at the same timing, so that the intensity of the R light (synthetic R light) reaching the collective reflecting mirror 15MR according to the interval between the light emitting groups ( (Brightness) can be adjusted.

  In other words, the intensity (brightness) of the combined R light is controlled according to the period of the ON signal output from the R light drive circuit 14R.

  Other B light circuits and G light circuits have basically the same configuration as the R light circuit described above. However, the B light collective reflecting mirror 15MB linearly transmits the R light reflected by the R light collective reflecting mirror 15MR and transmits the B light emitted by each of the B light LEDs 152B itself. It is a half mirror that reflects on the same optical axis as the optical axis. On the other hand, the G light collective reflector 15MG linearly transmits the G light emitted by each G light LED 152G and is reflected by the R light collective mirror 15MR and the B light collective mirror 15MB. The R light and the B light are reflected on the optical axis through which the G light passes through the G light collective reflecting mirror 15MG. Therefore, finally, the R, B, and G lights are emitted on the same optical axis from the G light collecting reflector 15MG. The R, B, and G lights emitted from the G light collective reflecting mirror 15MG are projected to the DMD 12 via the optical system 16.

  As described above, when white light is required, white light can be projected onto the DMD 12 by simultaneously emitting light of each color in the R light circuit, the B light circuit, and the G light circuit. Become. In addition, even when intermediate colors other than R, B, and G light, that is, cyan, magenta, and yellow light are required, the R light circuit, the B light circuit, and the G light circuit are selectively made to emit light simultaneously. It becomes possible to project the light of the color to the DMD 12.

  FIG. 3 is a block diagram showing a specific configuration example of the drive circuit 14 together with the LED circuit 15. However, here, as an example, a specific configuration example of the R light drive circuit 14R together with the R light LED circuit 15R is shown.

  The R light drive circuit 14R is stored at an address recorder 141R to which the subframe signal SFS included in the LED control signal LEDCS output from the DMD drive circuit 11 is given, and at an address corresponding to the decoding result of the address recorder 141R. Adjustment value memory 142R and correction value memory 144R that output data (adjustment data), read registers 143R and 145R that temporarily store data output from the adjustment value memory 142R and correction value memory 144R, and both registers An adder circuit 146R for adding data temporarily stored in 143R and 145R, a reload register 147R for loading and temporarily storing data of the addition result by the adder circuit 146R, a counter 149R for counting a predetermined clock CLK, Reload The comparator 148R that compares the data temporarily stored in the register 147R with the count value of the counter 149R and outputs a logic signal (comparison result signal RS) according to the comparison result, and the comparison result signal RS output by the comparator 148R And a two-input AND gate 155 to which an R light subframe period signal RSFPS included in the LED control signal LEDCS output from the DMD control drive circuit 11 is provided.

  Note that the output signal of the AND gate 155R is supplied to the pre-driver 156R. When the output signal of the AND gate 155R is “H (significant)”, the pre-driver 156R outputs an electrical signal that can turn on each switch 153R that is a transistor, and the output signal of the AND gate 155R is “L ( In other words, the amplifier does not output an electric signal that can turn on each switch 153R as a transistor, that is, outputs a drive current that turns off each switch 153R.

  The above-described subframe signal SFS is a signal indicating the period of each subframe obtained by dividing one frame of image data. The R light subframe period signal RSFPS is a period allocated for R light within the period of each subframe specified by the subframe signal SFS, more specifically, a period during which R light should be emitted. It is a signal which shows.

  The G light and B light drive circuits 14G and 14B other than the R light have the same configuration, and their operations are the same as those of the R light drive circuit 14R described below. However, the subframe signal SFS is supplied to the address decoders 141R, 141B, and 141G for the light of each color, but the subframe period signal SFPS is a signal for each color (RSFPS, BSFPS, GSFPS) for each color. Are provided to the drive circuits 14R, 14B, and 14G, respectively. Specifically, the R light subframe period signal RSFPS is a signal that becomes significant in the period allocated as the period during which the R light within each subframe period should be emitted, and is provided to the R light drive circuit 14R. . The sub-frame period signal BSFPS for B light is a signal that becomes significant in the period assigned as the period during which the B light within each sub-frame period should be emitted, and is given to the drive circuit 14B for B light. The sub-frame period signal GFPPS for G light is a signal that becomes significant during the period assigned as the period during which G light within each sub-frame period should be emitted, and is supplied to the drive circuit 14G for G light.

  Specifically, the R light LED circuit 15R has a plurality of LEDs 152R that emit a plurality of red lights (R light) each having one end connected to the R light power source 150R, and one end connected to the other end of each LED 152R. And a switch 153R which is a transistor formed. The other end of each switch 153R is installed, and the gate of each switch 153R is connected to the output terminal of the pre-driver 156R. Accordingly, the switches 153R are turned on / off according to the drive current output from the pre-driver 156R, and as a result, the LEDs 152R are controlled to emit light / not emit light simultaneously.

  The address decoder 141R is supplied with the subframe signal SFS from the DMD driving circuit 11. As described above, the subframe signal SFS is a signal indicating that it is the period of each subframe obtained by dividing each frame. The address decoder 141R decodes the subframe signal SFS to output any data in the adjustment value memory 142R to the read register 143R. Specifically, the adjustment value memory 142R (and the correction value memory 144R) stores the same number of adjustment value data (and correction value data) as the number of bits for expressing the gradation of each color. For example, in the case of 4-bit gradation, four adjustment value data (and correction value data) are stored in the adjustment value memory 142R (and correction value memory 144R). Then, the address decoder 141R outputs to the read register 143R the data of the adjustment value corresponding to the result of decoding the subframe signal SFS, in other words, the adjustment value corresponding to the subframe at that time.

  The adjustment value data stored in the adjustment value memory 142R is, for example, “100” for the first subframe, “50” for the second subframe, and “50” for the third subframe. For example, “25” and “12” for the fourth subframe are sequentially reduced according to the order of the subframes. However, although the correction value data stored in the correction value memory 144R is set regardless of the order of the subframes, details will be described later.

  The adjustment value data read from the adjustment value memory 142R and temporarily stored in the read register 143R is read to the comparator 148R through the adder 146R and temporarily stored in the reload register 147R. Here, it is assumed that addition is not performed in adder 146R (correction value data is “0”), and the operation when addition is performed will be described later.

  On the other hand, the counter 149R counts a predetermined clock CLK, and the count value is read to the comparator 148R. The comparator 148R compares data temporarily stored in the reload register 147R (added value of adjustment value data and correction value data) with the count value of the counter 149R. Specifically, the operation of the comparator 148R outputs the comparison result signal RS of “H (high level: significant)” until the count value of the counter 149R reaches the data temporarily stored in the reload register 147R, and thereafter Outputs a comparison result signal RS of “L (low level: useless)”. When the counter value of the counter 149R reaches a predetermined value, that is, when it overflows, the count value up to that point is automatically reset and starts counting the predetermined clock CLK again.

  By the way, as described above, when gradation is expressed by 4 bits, one frame is divided into four subframes. In this case, the period corresponding to the count value at which the counter 149R overflows is set to be the same as or longer than the period of the shortest subframe. More specifically, it is desirable that the period of the shortest subframe is set to be the same as the period corresponding to the count value at which the counter 149R overflows, or set to an integral multiple. For example, when the counter 149R overflows with the count value “128”, the period of 128 cycles of the predetermined clock CLK is set to be the same as the period of the shortest subframe, or the period of 128 cycles of the predetermined clock CLK is It is desirable to set to 1 / integer (1/2, 1/4, 1/8, etc.) of the shortest subframe period.

  The AND gate 155R has two inputs as described above, and in addition to the comparison result signal RS of the comparator 148R described above, the subframe period for the R light as described above included in the LED control signal LEDCS output from the DMD driving circuit. The signal SFPS is given. Therefore, the AND gate 155R is “H (significant)” only when the comparison result signal RS output from the comparator 148R is “H (significant)” and the R light subframe period signal RSHPS is “H (significant)”. Significant) "signal is output. Then, while the “H” signal is output from the AND gate 155R, the pre-driver 156R supplies a drive signal DS that can turn on each switch 153R, which is a transistor, to each gate.

  Each switch 153R, which is a transistor, receives an ON signal from its pre-driver 156R to its gate, whereby each LED 152R that emits red light (R light) emits light. Needless to say, when the output signal from the AND gate 155R becomes “L”, the drive signal DS output from the pre-driver 156R also becomes “L” (off signal), and thus the light emission of each LED 152R stops.

  Although the configuration and basic operation of the R light drive circuit 14R have been described above, the other B light drive circuit 14B and the G light drive circuit 14G have the same configuration, and therefore the basic operation of each is also the same. This is the same as that of the R light drive circuit 14R described above.

  Incidentally, as shown in FIG. 3, the R light emission circuit is provided with an R light optical sensor 157R for detecting the light emission amount of each LED 152R. An R light subframe period signal RSFPS is input to the R light optical sensor 157R. The R light optical sensor 157R integrates and detects the light emission amount (brightness) of each R light LED 125R only during the period when the R light subframe period signal RSFPS is input. It is configured. The detection result of the optical sensor 157R is given to the correction circuit 158R for R light as the detection signal RFBS.

  The R light correction circuit 158R stores a design value of the amount of R light emitted by the adjustment value data stored in the R light adjustment value memory 142R corresponding to each subframe. Therefore, the R light correction circuit 158R compares the detection signal RFBS of the R light optical sensor 157R with the design value stored in advance, thereby determining the actual light emission amount and the design value of the R light emission circuit. If there is a difference greater than or equal to a predetermined value, correction value data for correcting the difference is stored in the correction value memory 144R.

  Further, the adjustment device 159R for R light is prepared for manual adjustment by the user. That is, when the user wants to increase / decrease the red component of the projected image, it is possible to store arbitrary correction value data in the correction value memory 144R by operating the adjustment device 159R for R light.

  Note that the above-described optical sensor 157R, correction circuit 158R, adjustment device 159R, and the like are similarly provided in the other light emitting circuits for B light and G light. However, the operation of these elements will be described later.

  FIG. 4 is a timing chart showing an example of the relationship between the count value of the counter 149R and the output signal of the comparator 148R.

  As shown in FIG. 4 (a), the counter 149R starts counting the predetermined clock CLK from the count value “0”, overflows to “128”, overflows, and the count value is reset to “0”. The operation of starting counting, overflowing with the count value “128”, and resetting the count value to “0” is repeated. For example, when “100” is read from the adjustment value memory 142R as the adjustment value data to the read register 143R (assuming that correction value data is not added) and held in the reload register 147R, FIG. ), The output signal of the comparator 148R is “H” when the count value of the counter 149R is “0” to “100”, and “L” when the count value of the counter 149R becomes “101”. Turn to. Thereafter, the output signal of the comparator 148R remains “L” until the count value of the counter 149R reaches “128” and overflows, and when the count value of the counter 149R reaches “128” and overflows, the counter 149R is reset. Since the count value becomes “0”, the output signal of the comparator 148R changes to “H” again.

  Similarly, for example, when “50” is read as the adjustment value data from the adjustment value memory 142R to the read register 143R and held in the reload register 147R, the output signal of the comparator 148R as shown in FIG. Is “H” when the count value of the counter 149R is from “0” to “50”, and when the count value of the counter 149R becomes “51”, the counter value changes to “L”. Thereafter, the output signal of the comparator 148R remains “L” until the count value of the counter 149R reaches “128” and overflows, and when the count value of the counter 149R reaches “128” and overflows, the counter 149R is reset. Since the count value becomes “0”, the output signal of the comparator 148R changes to “H” again.

  The same applies to the cases where the adjustment value data is “25” and “12”, as shown in FIGS. 4D and 4E.

  From the above, the duty of the output signal from the comparator 148R, in other words, the ON signal output from the pre-driver 156R changes in direct proportion to the adjustment value data held in the reload register 147R. This means that the light emission of each R LED 152R is PWM-controlled in direct proportion to the adjustment value data output from the adjustment value memory 142R.

  FIG. 5 shows the output signal of the comparator 148R (FIG. 5A), the R light subframe period signal RSFPS (FIG. 5B), and the light emission period of each LED 152R for R light (FIG. 5C). It is a timing chart which shows the relationship.

  The output signal of the comparator 148R shown in FIG. 5 (a) is a solid line when the adjustment value data shown in FIG. 4 (a) is “100”, and the output signals are also “50”, “25”, and “12”. Each is indicated by a broken line. In a period in which the R light subframe period signal RSFP shown in FIG. 5B is “H (significant)”, a pulse signal having a duty ratio corresponding to the adjustment value data designated by the subframe signal SFS is compared with the comparator 148R. Output as an output signal, the light emission period of each LED 152R for R light shown in FIG. 5 (c) also emits light with a duty ratio corresponding to the adjustment value data specified by the subframe signal SFS. That is, the duty ratio according to the adjustment value data (adjustment value data corresponding to the subframe indicated by the subframe signal SFS) specified by the subframe signal SFS in the adjustment value data stored in the adjustment value memory 142R. Each LED 152R for R light emits light. In other words, the duty according to the adjustment value data (adjustment value data corresponding to the subframe indicated by the subframe signal SFS) specified by the subframe signal SFS in the adjustment value data stored in the adjustment value memory 142R. Each LED 152R for R light emits light with a brightness proportional to the ratio.

  Although the above description relates to the R light emitting circuit, it is obvious that the other B light emitting circuits and the G light emitting circuit operate in exactly the same manner as the R light emitting circuit.

  According to the spatial light modulation system according to the present invention as described above, light emission of each color by the R light circuit, the B light circuit, and the G light circuit corresponding to each color in the R, B, and G color display periods. The intensity can be PWM controlled. FIG. 6 is a timing chart showing an example of a driving method of the spatial light modulation system according to the present invention.

  For example, as shown in FIG. 6 (a), in the first subframe SF1 in one frame, the subframe period signals RSFPS for light for each color within the period of the subframe signal SFS0 indicating the first subframe SF1 A subframe indicating the second subframe SF2 when the length (time) of the first R, B, G display periods (R1, B1, G1) indicated by BSFPS and BSFPS is set to “1”, respectively. The length (time) of the second R, B, and G display periods (R2, B2, and G2) indicated by the subframe period signals RSFPS, BSFPS, and BSFPS for each color within the period of the signal SFS1 are as follows. The third R, B, respectively indicated by the optical subframe period signals RSFPS, BSFPS, BSFPS for each color within the period of the subframe signal SFS2 indicating the third subframe SF3 are respectively set to “1/2”. G display period (R3, B3, G3) length The length (time) is “1/4”, and the fourth subframe period signals RSFPS, BSFPS, and BSFPS for each color within the period of the subframe signal SFS3 indicating the fourth subframe SF4 are respectively indicated. Consider an example in which gradation representation is performed with 4 bits such that the length (time) of each of the R, B, and G display periods (R4, B4, and G4) is “1/8”. In this case, as shown in FIG. 6B, the light emission intensity of each color corresponding to each of the subframes SF1 to SF4 can be gradually reduced in four stages.

  Specifically, as described above in the adjustment value memories 142R, 142B, and 142G of the R light circuit, the B light circuit, and the G light circuit, the adjustment corresponding to the subframe signal SFS0 indicating the first subframe SF1. “100” as value data, “50” as adjustment value data corresponding to the subframe signal SFS1 indicating the second subframe SF2, and “50” as adjustment value data corresponding to the subframe signal SFS2 indicating the third subframe SF3. “25” is stored as adjustment value data corresponding to the subframe signal SFS3 indicating the fourth subframe SF4.

  In such a case, the first display period R1, B1, G1 of each color in the first subframe SF1 has a duty ratio of “100: 126”, and the second display of each color in the second subframe SF2. In the periods R2, B2, and G2, the duty ratio is “50: 126”, and in the third subframe SF3, the duty ratio is “25: 126” in the third display periods R3, B3, and G3 of the respective colors. In the fourth sub-frame SF4, the R-light drive circuit causes the LEDs 152R, 152B, and 152G for each color to emit light at a duty ratio of “12: 126” in the fourth display periods R4, B4, and G4 of the respective colors. 14R, B light drive circuit 14B, and G light drive circuit 14G are connected to switches 153R, 153B, 15 respectively. To control the G.

  Needless to say, the light emission control by the drive circuits 14R, 14B, and 14G as described above is synchronized with the timing at which the DMD drive circuit 11 drives the DMD 12 by the LED control signal LEDSC provided from the DMD drive circuit 11.

  In this manner, the light intensity of the light of each color from the light source is reduced by the PWM control in the subframe in which the display time for expressing the low gradation portion of the image is relatively short, so that it is included in the image signal. Since it is possible to express a portion having a low gradation degree with a lower gradation degree intentionally, it is possible to express a gamma curve.

  By the way, the optical sensor 157R of the circuit for R light shown in FIG. 3 is provided for detecting the light emission amount of each LED 125R for R light. The optical sensor 157R receives the R light subframe period signal RSFPS, and integrates the amount of light emitted from each LED 125R for R light during the period in which the R light subframe period signal RSFPS is input. Configured to detect. The detection result of the optical sensor 157R is given to the correction circuit 158R as a detection signal RFBS.

  Accordingly, when the detection result in any subframe of the optical sensor 157R does not match the design value, for example, the correction circuit 158R corrects the correction corresponding to the subframe in which the design value and the light emission amount (brightness) do not match. Correction value data is stored in the address of the value memory 144R. In the example shown in FIG. 3, “+3” is corrected as correction value data in the address of the correction value memory 144R corresponding to the first subframe, and correction is performed in the address of the correction value memory 144R corresponding to the second subframe. “−2” as the value data, “−1” as the correction value data for the address of the correction value memory 144R corresponding to the third subframe, and correction for the address of the correction value memory 144R corresponding to the fourth subframe. “0” is stored as value data.

  Further, the adjustment device 159R for R light is prepared for manual adjustment by the user. That is, when the user wants to increase or decrease the red component of the image actually projected on the screen or the like, the adjustment value data stored in the correction value memory 144R is changed by operating the adjustment device 159R for R light. Is possible. As a result, the red component of the projected image is increased or decreased according to the operation of the adjustment device 159R by the user.

  In the above description, the R light circuit has been described, but the other B light and G light circuits have the same configuration and the operation is also similar. Further, the adjustment circuit is not provided for individual colors, but a common adjustment circuit may be provided to adjust the overall color balance and the like.

  As described above in detail, according to the spatial light modulation system and the projector according to the present invention, the brightness of the image can be adjusted by combining the display time of each color and the light emission period of the corresponding color light source by PWM control. It becomes possible to express more detailed gradation and to easily express a so-called gamma curve. In addition, it is possible to reduce the amount of power used as compared with the case where the length of the image display period is changed while maintaining the light source at a constant light emission intensity. Furthermore, it is possible to cope with an application in which the luminance of an image called a data projector is given priority only by a light source that emits R, B, and G light only by light emission control of the light source. It is also possible to easily perform finer color expression using intermediate colors such as cyan, magenta, and yellow.

  Furthermore, according to the driving method of the spatial light modulation system and the projector according to the present invention, images of each color separated into a plurality of chromatic colors are displayed a plurality of times during one frame of the image signal, Since the light emission period can be changed by PWM control, the brightness of the image can be adjusted by combining the display time of each color and the light emission period of the corresponding color light source. Therefore, it becomes possible to express a finer gradation, to easily express a so-called gamma curve, and to display an image with higher contrast. Furthermore, it is possible to express a gamma curve without performing prior image processing. Furthermore, it is possible to reduce the amount of power used compared to the case where the length of the image display period is changed while maintaining the light source at a constant light emission intensity. Furthermore, it is possible to deal with an application in which the luminance of an image called a so-called data projector is prioritized only by PWM control of the light emission period of the light source, and intermediate colors such as cyan, magenta, and yellow are used. Thus, it is possible to easily perform finer color expression.

  Further, according to the spatial light modulation system and the projector according to the present invention, it is possible to detect the light amount of each color actually emitted and automatically perform feedback control so as to obtain a design value. Therefore, it is not necessary to perform the process so carefully, and it is possible to automatically correct the aging of the LED.

  In the above-described embodiment, the case where gradation expression is performed with 4 bits is illustrated. However, this is for convenience of explanation, and gradation expression is performed with an arbitrary number of bits when designing an actual system. it can. In addition, the number of LEDs shown in FIG. 2 can also be provided with an arbitrary number (1 or 4 or more) in order to obtain a combined light having a required intensity. Furthermore, in the embodiment described above, light sources of three colors R, B, and G are used, but light sources of other colors may be used depending on the application.

It is a schematic diagram which shows the structural example of the principal part at the time of incorporating one Embodiment of the spatial light modulation system which concerns on this invention in the projector as an example of a DLP system. It is a block diagram which shows the structure of the LED circuit and LED drive circuit of the spatial light modulation system which concerns on this invention. It is a block diagram which shows the specific structural example of a drive circuit with the LED circuit of the spatial light modulation system which concerns on this invention. It is a timing chart which shows an example of the relationship between the count value of the counter of the spatial light modulation system which concerns on this invention, and the output signal of a comparator. FIG. 6 is a timing chart showing the relationship among the output signal (a) of the comparator of the spatial light modulation system according to the present invention, the subframe period signal for R light (b), and the light emission period (c) of each LED for R light. is there. It is a timing chart which shows an example of the drive method of the spatial light modulation system which concerns on this invention. It is a timing chart which shows the display timing of each color for 1 frame of the image signal in the single plate type DLP system using the conventional general color wheel. It is the timing chart which showed the display timing of each color of a prior art simply. It is the timing chart which showed the display timing of each color of a prior art simply.

Explanation of symbols

11 DMD drive circuit 12 DMD
13 Projection lens 14 LED drive circuit 14R, 14B, 14G Drive circuit 142R, 142B, 142G Adjustment value register 144R, 144B, 144G Correction value register 15R, 15B, 15G LED circuit 152R, 152B, 152G LED
147R, 147B, 147G Reload register 148R, 148B, 148G Comparator 149R, 149B, 149G Counter 153R, 153B, 153G Switch 155R, 155B, 155G AND gate 158R, 158B, 158G Correction circuit

Claims (10)

A plurality of light sources that respectively emit light of different chromatic colors, and an image signal corresponding to the chromatic light emitted by each of the plurality of light sources is converted into modulated light that represents each of a plurality of chromatic color components , and an image The period of one frame of the signal is divided into a plurality of periods in which the display time sequentially changes for each of the plurality of chromatic colors to form sub-frames, and whether each sub-frame is displayed or not is controlled. A spatial light modulator that expresses the gradation of a chromatic component, and a spatial light modulator that separates an image signal into a plurality of chromatic components corresponding to the chromatic light emitted by each of the plurality of light sources. Spatial light modulation device control means for supplying, timing for the spatial light modulation device to convert an image signal into modulated light representing each of a plurality of chromatic components, and timing for emitting chromatic light corresponding to the plurality of light sources Same In the spatial light modulation system comprising a light source control means for,
The light source control means,
Storage means for storing data set to different values according to each subframe;
Pulse signal generating means for generating a pulse signal having a cycle shorter than each period of the subframe and having a duty ratio corresponding to data stored in the storage means;
Driving means for causing each of the light sources to emit chromatic light according to the duty ratio of the pulse signal generated by the pulse signal generating means;
Spatial light modulation system characterized Rukoto equipped with. Detecting means for detecting chromatic light emitted by each of the light sources;
Correction means for generating correction data for changing a light emission period of chromatic light emitted by each of the light sources according to a detection result by the detection means;
Correction data storage means for storing correction data generated by the correction means, and
The light source control means includes data correction means for correcting data stored in the storage means with correction data stored in the correction data storage means ,
The pulse signal generation means has a duty ratio corresponding to the data corrected by the data correction means, and generates a pulse signal having a cycle shorter than the period of the subframe,
The drive means is configured to cause each of the light sources to emit chromatic light according to a duty ratio of a pulse signal generated in response to data corrected by the data correction means by the pulse signal generation means. The spatial light modulation system according to claim 1. The plurality of chromatic colors are red, blue, and green, and the light source control means selectively emits all or any two of the light sources that emit light of each color, whereby white light or cyan, magenta, 3. The spatial light modulation system according to claim 1, wherein the spatial light modulation system is configured to emit light of any one of yellow colors. 4. Different from the plurality of light sources chromatic light emitting respectively, converts the image signals into modulated light representing a plurality of chromatic color component corresponding to the chromatic color light by the plurality of light sources emit light, respectively, images signals The one frame period is divided into a plurality of periods in which the display time sequentially changes for each of the plurality of chromatic colors to form sub-frames, and each chromatic color component is determined by whether or not each sub-frame is displayed . In a driving method of a spatial light modulation system including a spatial light modulation device that expresses gradation ,
The sub-frame is configured such that display periods of different colors having the same display time are continuous,
A light source of a corresponding color among the plurality of light sources is synchronized with a display period of each color included in each subframe , and has a cycle shorter than each period of the subframe, and a different duty corresponding to each subframe. A method for driving a spatial light modulation system, characterized in that light is emitted with a pulse signal of a ratio. 5. The method of driving a spatial light modulation system according to claim 4, wherein the duty ratio of a pulse signal for causing the plurality of light sources to emit light is adjusted according to the length of display time of the subframe. 5. The method of driving a spatial light modulation system according to claim 4 , wherein a duty ratio of a pulse signal for causing the plurality of light sources to emit light is varied in direct proportion to the length of display time of each subframe. Detecting chromatic light emitted by each of the light sources by a detecting means,
The spatial light according to any one of claims 4 to 6 , wherein a duty ratio of a pulse signal for causing the plurality of light sources to emit light is changed in accordance with a difference between a detection result by the detection means and a predetermined value. A method for driving a modulation system. The plurality of chromatic colors are red, blue, and green. By selectively emitting all or any two of the light sources, white light or light of any color of cyan, magenta, and yellow is emitted. spatial light driving method of the modulation system according to any one of claims 4 to 7, characterized in that to. A spatial light modulator system according to any one of claims 1 to 3, the projector in which the spatial light modulator is characterized by comprising a projection lens for projecting the modulated light converted. A projector having a projection lens for projecting the spatial light modulation system, the modulated light in which the spatial light modulator is converted, space according to any one of the spatial light modulator system according to claim 4 to 8 A projector driven by a driving method of a light modulation system.

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