JP5672019B2 - Position detection system and position detection method - Google Patents

Description

  The present invention relates to a position detection system and a position detection method using an image display device.

  An input system that detects the position of an indicator (such as an electronic pen) that indicates an arbitrary point in an image projected on a screen from a projector and displays an image corresponding to the position is disclosed in Patent Document 1. The input system disclosed in Patent Document 1 can display an image corresponding to the position of the indicator without using a special screen by executing a calibration process in advance.

JP 2010-113598 A

  However, the calibration process requires a certain time. For this reason, even if the user installs a position detection system (input system), there is a problem that the position detection system cannot be used until the calibration process is completed.

  The present invention has been made in view of the above points, and can display an image corresponding to the position of the indicator without using a special screen and without performing a calibration process. An object is to provide a position detection system and a position detection method using the apparatus.

The present invention has been made in order to solve the above-described problem, and includes an indicator that receives a light pulse, detects a timing of the light pulse, and a transmission unit that transmits a signal representing the timing. A receiving unit that receives a signal representing the timing from the transmitting unit, a plurality of light sources that project light pulses at a specific timing for each light source, and an area obtained by dividing the screen into a plurality of regions, and the timing An image display device comprising: a control unit that detects a position of the indicator on the screen on which an image is displayed based on a signal to be displayed.
With this configuration, since the position detection system detects the position of the indicator on the screen based on the timing of the light pulse, the position of the indicator is not required without using a special screen and performing a calibration process. It is possible to display an image in accordance with (interactive operation).

Further, according to the present invention, each light source projects a light pulse at a timing specific to each light source to the region corresponding to the light source and a region adjacent to the region, and the control unit includes: The position detection system is characterized in that the position of the indicator is detected based on timings of a plurality of light pulses from one light source and one or more light sources adjacent to the light source.
With this configuration, the position detection system detects the position of the indicator on the screen based on each timing of a plurality of light pulses from one light source and one or more light sources adjacent to the light source. Thus, an image corresponding to the position of the indicator can be displayed.

Further, the present invention is the position detection system, wherein the control unit detects the position of the indicator based on a ratio of the intensity of each light pulse from a plurality of adjacent light sources.
With this configuration, the position detection system detects the position of the indicator based on the ratio of the intensity of each light pulse from a plurality of adjacent light sources, thereby displaying an image corresponding to the position of the indicator. be able to.

Further, in the present invention, the control unit detects the position of the indicator based on an interval between a first pulse from a plurality of light sources and a second pulse following the first pulse. It is.
With this configuration, the position detection system detects the position of the indicator based on the interval between the first pulse from the plurality of light sources and the subsequent second pulse, so that an image corresponding to the position of the indicator is displayed. Can be displayed.

The present invention also includes a sensor that receives a light pulse and detects a timing of the light pulse, a control unit that detects a position of the device on a screen on which an image is displayed based on the timing, and the position An indicator having a transmission unit that transmits a signal representing the position, a reception unit that receives the signal representing the position from the transmission unit, and a timing specific to each light source with respect to the area obtained by dividing the screen into a plurality of areas A position detection system comprising: an image display device having a plurality of light sources for projecting light pulses.
With this configuration, since the position detection system detects the position of the indicator on the screen based on the timing of the light pulse, the position of the indicator is not required without using a special screen and performing a calibration process. It is possible to display an image in accordance with (interactive operation).

Moreover, the present invention is a position detection system comprising a plurality of the indicators.
With this configuration, the position detection system can display images corresponding to the positions of a plurality of indicators (multi-touch).

The present invention is also a position detection method in a position detection system, wherein a sensor included in the indicator receives a light pulse and detects a timing of the light pulse, and a transmission unit included in the indicator includes: A step of transmitting a signal representing timing, a step of receiving a signal representing the timing from the transmitting unit, and a plurality of light sources included in the image display device dividing the screen into a plurality of parts. The indicator on the screen on which an image is displayed on the basis of a step of projecting a light pulse to the region at a timing specific to each light source, and a control unit provided in the image display device based on a signal representing the timing And a step of detecting the position of the position.
By this method, since the position detection system detects the position of the indicator on the screen based on the timing of the light pulse, it is possible to use the indicator without using a special screen and performing the calibration process. An image corresponding to the position can be displayed.

  According to the present invention, since the position detection system detects the position of the indicator on the screen based on the timing of the light pulse, the instruction is performed without using a special screen and without executing the calibration process. An image corresponding to the position of the vessel can be displayed.

It is a figure showing the structure of the position detection system in one Embodiment of this invention. It is a figure showing the structure of the projection part in one Embodiment of this invention. It is a figure showing the structure of the red light source part in one Embodiment of this invention. It is a figure showing the optical pulse projected with the intrinsic | native timing for every light source in one Embodiment of this invention. It is a figure showing the relationship between a screen position and light intensity in one Embodiment of this invention. It is a figure showing the positional relationship of the area | region and projection range in one Embodiment of this invention. It is a figure showing the relationship between the light pulse projected on the liquid crystal light valve and the light pulse projected on the screen in one Embodiment of this invention. It is a figure showing the light pulse projected on the screen in one Embodiment of this invention. It is a figure for demonstrating the method to detect the inclination of the vector according to the designated position in one Embodiment of this invention. It is a figure for demonstrating the method to detect the indication position in one Embodiment of this invention. It is a flowchart showing the procedure in which position detection system detects an indication position in one embodiment of the present invention.

[First Embodiment]
A first embodiment of the present invention will be described in detail with reference to the drawings. In the position detection system, the indicator receives a light pulse on the screen and transmits a signal indicating the timing of the received light pulse. Further, the position detection device receives a signal representing the timing of the light pulse, and detects the position of the indicator on the screen based on the received signal. The image display device displays an image corresponding to the detected position of the indicator.

  FIG. 1 shows the configuration of the position detection system. The position detection system includes an image display device 1000 and an indicator 2000. The indicator 2000 is a pointing device (for example, an electronic pen) for indicating a position on the screen. The indicator 2000 includes a photodiode 2010, an A / D conversion unit 2020, and a transmission unit 2030.

  The photodiode 2010 receives the light pulse and detects the intensity of the received light pulse. The A / D converter 2020 outputs a digital signal indicating the timing of the light pulse detected by the photodiode 2010. Here, the timing of the light pulse is detected by, for example, a voltage difference corresponding to the amount of received light.

  The transmission unit 2030 transmits a signal representing the timing of the optical pulse. Note that a plurality of indicators 2000 may be provided in the position detection system (multi-touch). In this case, the transmission unit 2030 transmits an identification number for identifying each indicator.

The image display device 1000 includes a position detection device 1100 and a projection unit 1200. The position detection apparatus 1100 includes a control unit 1110, a liquid crystal drive unit 1120, a signal generation unit 1130, a red light source drive unit 1140R, a green light source drive unit 1140G, a blue light source drive unit 1140B, and a reception unit 1150. .

  The reception unit 1150 receives a signal representing the timing of the optical pulse from the transmission unit 2030 of the indicator 2000 and transfers it to the control unit 1110. When a plurality of indicators 2000 are provided in the position detection system, the reception unit 1150 transfers a signal indicating the timing of the light pulse to the control unit 1110 for each received identification number.

  FIG. 2 shows the configuration of the projection unit. The projection unit 1200 includes a cross dichroic prism 400 and a projection optical system 500. The projection unit 1200 includes a red light source unit (R-LED array) 100R, a red light collimator optical system 200R, and a red light liquid crystal light valve 300R. The projection unit 1200 includes a green light source unit (G-LED array) 100G, a green light collimator optical system 200G, and a green light liquid crystal light valve 300G. The projection unit 1200 includes a blue light source unit (B-LED array) 100B, a blue light collimator optical system 200B, and a blue light liquid crystal light valve 300B. Each light source unit may be provided in the position detection device 1100 instead of the projection unit 1200.

  FIG. 3 shows the configuration of the red light source unit. The red light sources 101R to 112R are, for example, LEDs (Light Emitting Diode), and project red light LR. Each light source has a unique timing for each light source with respect to a region corresponding to its own light source and a region adjacent to the region among regions obtained by dividing the screen 3000 into a plurality of regions (described later with reference to FIGS. 5 and 6). Project a light pulse.

  The red light sources 101R to 112R are arranged in, for example, 3 rows and 4 columns so as to have a shape similar to the red light liquid crystal light valve 300R (see FIG. 2). The green light source unit 100G and the blue light source unit 100B have the same shape as the red light source unit 100R.

  Returning to FIG. 2, the description of the configuration of the projection unit will be continued. The red light collimator optical system 200R includes a plurality of lenses, and uniformizes the illuminance distribution of the red light LR projected by the red light source unit 100R in the red light liquid crystal light valve 300R. The same applies to the green light collimator optical system 200G and the blue light collimator optical system 200B.

  The red light liquid crystal light valve 300R, the green light liquid crystal light valve 300G, and the blue light liquid crystal light valve 300B are light modulation elements. The red light LR modulated by the red light liquid crystal light valve 300 </ b> R enters the cross dichroic prism 400. The green light LG modulated by the green light liquid crystal light valve 300G enters the cross dichroic prism 400 from a direction different from that of the red light LR. Further, the blue light LB modulated by the blue light liquid crystal light valve 300B enters the cross dichroic prism 400 from a different direction from the red light LR and the green light LG.

  The cross dichroic prism 400 has a structure in which right-angle prisms are bonded together. On the inner surface of the structure, a mirror surface that reflects the red light LR and a mirror surface that reflects the blue light LB are formed in a cross shape. Yes. The red light LR, the green light LG, and the blue light LB are combined by these mirror surfaces, and the combined light forms an image.

  The projection optical system 500 has a projection lens. The image formed by the cross dichroic prism 400 is enlarged and projected onto the screen 3000 by the projection lens. In this way, the projection unit 1200 projects an image on the screen 3000 (screen) using the light emission of each light source unit.

  Returning to FIG. 1, the description of the configuration of the position detection system will be continued. The control unit 1110 receives an image signal and a control signal. The control unit 1110 performs predetermined signal processing on the image signal based on the control signal. The control unit 1110 is, for example, a DSP (Digital Signal Processor). Further, the control unit 1110 outputs a synchronization signal synchronized with the image display timing to the signal generation unit 1130. Here, the synchronization signal is, for example, a vertical synchronization signal (Vsync).

  A signal representing the timing of the optical pulse is input from the receiving unit 1150 to the control unit 1110. When the position detection system includes a plurality of indicators 2000, an identification number for identifying each indicator is input to the control unit 1110 from the reception unit 1150. The control unit 1110 detects a position on the screen (hereinafter referred to as “indicated position”) instructed by the indicator 2000 based on a signal representing the timing of the light pulse. Here, the control unit 1110 detects the indicated position based on each timing of a plurality of light pulses from one light source and one or more light sources adjacent to the light source. A method for detecting the designated position will be described later with reference to FIGS. 4 and 9 to 11.

  The control unit 1110 outputs an image signal representing an image (interactive image) corresponding to the designated position to the liquid crystal driving unit 1120. For example, the control unit 1110 outputs an image signal representing an image in which the cursor is superimposed on the designated position to the liquid crystal driving unit 1120 so that the cursor is displayed at the designated position.

  A liquid crystal drive unit (light modulation element drive unit) 1120 drives each liquid crystal light valve (light modulation element) (see FIG. 2) in accordance with an image signal representing an image corresponding to the designated position. The signal generation unit 1130 controls the red light source driving unit 1140R, the green light source driving unit 1140G, and the blue light source driving unit 1140B in synchronization with the synchronization signal.

  The red light source driving unit 1140R drives the red light source unit 100R in accordance with control by the signal generation unit 1130. Here, the red light source driving unit 1140R individually generates a light pulse whose timing is unique for each of the red light sources 101R to 112R (see FIG. 3) from each light source with respect to an area on the screen 3000 corresponding to the own light source. Project. The same applies to the green light source driving unit 1140G and the blue light source driving unit 1140B.

Next, the light pulse will be described.
FIG. 4 shows light pulses projected at a timing specific to each light source. In the light pulse, the interval between the start pulse and the subsequent position detection pulse is unique for each light source. Here, each start pulse is projected from each light source at the same timing.

  In FIG. 4, the light pulse emitted from the red light source 101R has the shortest interval between the start pulse and the position detection pulse. Further, the light pulse emitted from the red light source 112R has the longest interval between the start pulse and the position detection pulse. Here, the longest interval between the start pulse and the position detection pulse is determined in advance as a time required to detect all the position detection pulses. Hereinafter, the description will be continued assuming that the light pulse is emitted from each light source with the same intensity. Note that the intensity (level) of light other than the light pulse may vary depending on the image displayed on the screen, for example.

  The designated position (coordinates) on the screen on which the image is displayed is detected by the control unit 1110 based on a signal representing the timing of the light pulse. The time interval between the light pulses is measured by the control unit 1110 by updating the counter at a predetermined period. Here, the detection cycle, which is the interval between the start pulse and the next start pulse, is shorter than the display cycle of one frame image, for example, 1 [ms]. Since the detection cycle is shorter than the display cycle of one frame image, the control unit 1110 can detect the designated position in a short time. In addition, the user can view the projected image almost without being affected by the change in the amount of light caused by the light pulse.

  FIG. 5 shows the relationship between the screen position and the light intensity. The screen 3000 is divided in advance into areas of 3 rows and 4 columns corresponding to each light source (see FIG. 3). For example, the area 1 of the screen 3000 corresponds to the red light source 101R. For example, the area 2 of the screen 3000 corresponds to the red light source 102R. Similarly, areas 3 to 12 of the screen 3000 correspond to the red light sources 103R to 112R, respectively. The same applies to the green light source unit 100G and the blue light source unit 100B (see FIG. 2).

  As shown in the lower part of FIG. 5, the light pulse is projected from each light source to the region and a region adjacent to the region. Thereby, the light intensity in the screen 3000 becomes substantially uniform.

  The light pulse projected on the screen 3000 may be projected from any of the red light source unit 100R, the green light source unit 100G, and the blue light source unit 100B. Below, the case where the light pulse projected on the screen 3000 is projected from the red light source part 100R as an example is demonstrated.

  FIG. 6 shows the positional relationship between the area and the projection range. In FIG. 6, each center of the projection range (circular shape) on which the light pulse is projected and each center of the region are determined at the same position. A point shown in the region 6 (a point indicated by an arrow in the figure) represents a designated position. In the following, it is assumed that the indicated position is included in a projection range by the light source 102R, a projection range by the light source 106R, and a projection range by the light source 107R as an example.

  FIG. 7 shows the relationship between the light pulse projected on the liquid crystal light valve and the light pulse projected on the screen. In FIG. 7, the light pulse transmitted through the pixel region 306 </ b> R constituting the red light liquid crystal light valve 300 </ b> R is projected onto the region 6 of the screen 3000. Hereinafter, the position where the light pulse projected to the indicated position has passed through the liquid crystal light valve is referred to as “transmission position”.

  Further, it is assumed that the distance from the red light source 106R to the transmission position is shorter than the distance from the red light source 102R to the transmission position and the distance from the red light source 106R to the transmission position. As a result, even when light pulses having the same intensity are emitted from the red light source 102R and the red light source 106R, the light pulse projected from the red light source 102R at the transmission position is more than the light pulse projected from the red light source 106R. The intensity decreases according to the path distance of the light pulse.

  As an example, it is assumed that the light pulse projected from the red light source 102R has an intensity of 20 at the transmission position. On the other hand, the intensity of the light pulse projected from the red light source 106R is 160 at the transmission position. These light pulses overlap each other at the transmission position.

  Here, the transmittance of the pixel region 306R is, for example, 50 [%] (= 0.50). The start pulse in which the start pulse projected from the red light source 102R and the start pulse projected from the red light source 106R overlap has an intensity of 90 (= (level 20 + level 160) × transmittance 0 at the indicated position on the screen 3000. .50). On the other hand, the position detection pulse projected from the red light source 102R has an intensity of 10 (= level 20 × 0.50) at the indicated position on the screen 3000. Similarly, the intensity of the position detection pulse projected from the red light source 106R is 80 (= level 160 × 0.50) at the indicated position on the screen 3000.

  FIG. 8 shows light pulses projected on the screen. Since the indication position is included in any of the projection range by the light source 102R, the projection range by the light source 106R, and the projection range by the light source 107R (see FIG. 6), the start pulse at the indication position is from the red light source 102R. The projected start pulse, the start pulse projected from the red light source 106R, and the start pulse projected from the red light source 107R are overlapped. In FIG. 8, the overlapping start pulses have an intensity of 100 (= (level 20 + level 160 + level 20) × transmittance 0.50). On the other hand, the position detection pulses are not overlapped because they are emitted at different timings. Therefore, to calculate the intensity of each position detection pulse at the indicated position, it is only necessary to multiply the intensity at the transmission position by the transmittance 0.50.

  Since the indication position is included in any of the projection range by the light source 102R, the projection range by the light source 106R, and the projection range by the light source 107R (see FIG. 6), the position detection pulse at the indication position includes a red light source. There are three position detection pulses, a position detection pulse projected from the red light source 106R, and a position detection pulse projected from the red light source 107R. In FIG. 8, the intensity of the position detection pulse projected from the red light source 102R is 10. The intensity of the position detection pulse projected from the red light source 106R is 80. The intensity of the position detection pulse projected from the red light source 107R is 10.

  In FIG. 8, the intensity of the overlapping start pulse: the intensity of the position detection pulse from the red light source 102R: the intensity of the position detection pulse from the red light source 106R: the intensity of the position detection pulse from the red light source 107R = 1.0: 0. 1: 0.8: 0.1. That is, the intensity of the position detection pulse from the red light source 102R: the intensity of the position detection pulse from the red light source 106R: the intensity of the position detection pulse from the red light source 107R = 1: 8: 1.

  FIG. 9 is a diagram for explaining a method of detecting the inclination of a vector corresponding to the designated position. The inclination of this vector is the inclination of the vector connecting from the center of the region 6 corresponding to the red light source 106R that has projected the position detection pulse having the largest intensity ratio among the position detection pulses (see FIG. 8) to the designated position. It is. Further, the control unit 1110 calculates the ratio between the intensity of the overlapping start pulse and the intensity of each position detection pulse (see FIG. 8) projected on the areas 2, 5, 7 and 10 adjacent to the area 6. The In addition, the control unit 1110 may calculate a ratio between the intensity of each position detection pulse projected on the regions 2, 5, 7, and 10 adjacent to the region 6.

The ratio of the overlap and the strength of the start pulses, the intensity of the red light source 105R or we projected position detection pulse is 100: 0. The ratio between the intensity of the overlapped start pulse and the intensity of the position detection pulse projected from the red light source 110R is also 100: 0. The ratio of the intensity of the overlapping start pulse and the intensity of the position detection pulse projected from the red light source 102R is 1: 0.1. The ratio between the intensity of the overlapped start pulse and the intensity of the position detection pulse projected from the red light source 107R is also 1: 0 . 1. From these intensity ratios, the control unit 1110 detects that the vector is inclined 45 degrees counterclockwise with respect to the horizontal direction (row direction) of the screen.

  FIG. 10 is a diagram for explaining a method of detecting the designated position. The distance from the region 2 corresponding to the red light source 102R to the designated position is determined based on the fact that the ratio of the intensity of the position detection pulse projected from the red light source 102R is 0.1. It is detected by referring to (Up Table, LUT). In this look-up table, the relationship between the intensity ratio of the position detection pulse and the distance from the center of the region on the screen 3000 is measured and registered in advance.

  The designated position (coordinates) is detected by the control unit 1110 based on the vector inclination 45 degrees and the distance from the center of the region 2 to the designated position. When there are two light sources having the largest intensity ratio of light pulses, the designated position is at the boundary between regions corresponding to these light sources.

Next, a procedure for detecting the indicated position by the position detection system will be described.
FIG. 11 is a flowchart showing a procedure for the position detection system to detect the designated position. The procedure shown in FIG. 11 is executed at a predetermined detection cycle. It is assumed that control unit 1110 detects a start pulse in a signal representing the timing of the light pulse (step S1). The control unit 1110 updates a counter for measuring the interval between the light pulses in order to further detect the position detection pulse (step S2).

  The controller 1110 determines whether or not a position detection pulse has been detected, that is, whether or not data having a predetermined voltage difference in a signal representing the timing of the optical pulse has been detected (step S3). When the position detection pulse is not detected (step S3-NO), the process of the control unit 1110 returns to step S2. On the other hand, when the position detection pulse is detected (step S3-YES), the control unit 1110 detects which light source is the light source that projected the position detection pulse, based on the updated counter value. Further, the control unit 1110 detects the intensity of the position detection pulse based on the signal representing the timing of the light pulse (step S4).

  Control unit 1110 determines whether or not the predetermined maximum value matches the counter value (step S5). When the predetermined maximum value does not match the counter value (step S5-NO), the process of the control unit 1110 returns to step S2. On the other hand, when the predetermined maximum value matches the counter value (step S5-YES), the control unit 1110 calculates the ratio between the intensity of the overlapping start pulse and the intensity of other position detection pulses. Further, the control unit 1110 detects a region corresponding to the light source having the largest ratio between the intensity of the start pulse and the intensity of the position detection pulse (see FIG. 8) (step S6).

  The control unit 1110 detects the inclination of the vector according to the designated position (see FIG. 9). Further, the control unit 1110 refers to the look-up table and calculates the distance from the center of the region to the designated position based on the ratio to the intensity of the position detection pulse (see FIG. 10), thereby indicating the designated position ( Coordinates) is detected (step S7). In this way, since the designated position is detected based on the intensity ratio of the light pulses, the position detection system can display an image corresponding to the designated position without being affected by noise.

  In addition, the control part which detects an instruction | indication position may be provided in the indicator. In this case, the position detection system receives a light pulse and detects the timing of the light pulse, and a control unit that detects the position of the device on the screen on which an image is displayed based on the timing. (Not shown), an indicator having a transmission unit 2030 for transmitting the signal representing the position, a receiving unit 1150 for receiving the signal representing the position from the transmission unit 2030, and an area obtained by dividing the screen into a plurality of parts On the other hand, an image display device including a plurality of red light source units 100R, a green light source unit 100G, and a blue light source unit 100B that project light pulses at a timing specific to each light source is provided.

[Second Embodiment]
The second embodiment is different from the first embodiment in that the projection range in which the light pulse is projected does not overlap with other projection ranges. In the second embodiment, only differences from the first embodiment will be described.

  The red light sources 101R to 112R (see FIG. 3) project light pulses at a timing specific to each light source only in a region corresponding to the self light source. That is, each light source projects a light pulse only to a region corresponding to its own light source so that the projection range in which the light pulse is projected does not overlap with other projection ranges.

  Further, the control unit 1110 detects the position of the indicator 2000 for each region based only on the interval between the start pulse and the position detection pulse in the signal representing the timing. Since the projection ranges do not overlap each other, only one position detection pulse corresponding to the position of the indicator 2000 is detected in the signal representing the timing. The control unit 1110 detects that the designated position is within the region corresponding to this one position detection pulse.

  With this configuration, the position detection system detects the position of the indicator for each region based on the interval between the start pulse and the position detection pulse unique to each light source. A corresponding image can be displayed.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  For example, in the above description, the LED array is used as the light source unit. However, the optical configuration is not limited to the configuration including the LED array as long as the light source can be controlled for each region of the projection screen. For example, the optical configuration may be a configuration in which light from an LD (Laser Diode) array can be shaped in an illumination area by a hologram element (diffractive optical element). Accordingly, the position detection system can illuminate the screen uniformly without waste while overlapping the illumination areas as compared with the case where the lens optical system is used.

  Note that the program for realizing the position detection system and the position detection method described above may be recorded on a computer-readable recording medium, and the program may be read into the computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible disk, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” is a volatile memory (RAM) inside a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

100R: Red light source (R-LED array), 101R to 112R ... Red light source (R-LED), 100G ... Green light source (G-LED array), 100B ... Blue light source (B-LED array), 200R ... Collimator optical system for red light, 200G ... collimator optical system for green light, 200B ... collimator optical system for blue light, 300R ... liquid crystal light valve (light modulation element) for red light, 302R, 306R, 310R ... pixel region , 300G: liquid crystal light valve for green light (light modulation element), 300B: liquid crystal light valve for blue light (light modulation element), 400: cross dichroic prism, 500: projection optical system, 1000: image display device, 1100: position Detection device, 1110 ... control unit (DSP), 1120 ... liquid crystal drive unit, 1130 ... signal generation unit, 1140R ... red Light source drive unit, 1140G ... green light source drive unit, 1140B ... blue light source drive unit, 1150 ... reception unit, 1200 ... projection unit, 2000 ... indicator (electronic pen), 2010 ... photodiode, 2020 ... A / D conversion unit, 2030 ... Transmitter, 3000 ... Screen

Claims (7)

A sensor that receives the light pulse and detects the timing of the light pulse;
A transmission unit for transmitting a signal representing the timing;
An indicator having
A receiver that receives a signal representing the timing from the transmitter;
A plurality of light sources that project light pulses at a specific timing for each light source, with respect to a region divided into a plurality of screens,
A control unit for detecting a position of the indicator on the screen on which an image is displayed based on a signal representing the timing;
An image display device comprising:
A position detection system comprising: Each light source projects a light pulse at a timing specific to each light source with respect to the region corresponding to the light source and a region adjacent to the region,
The control unit detects the position of the indicator based on each timing of a plurality of light pulses from one light source and one or more light sources adjacent to the light source. The described position detection system.   The position detection system according to claim 1, wherein the control unit detects the position of the indicator based on a ratio of the intensity of each light pulse from a plurality of adjacent light sources.   The said control part detects the position of the said indicator based on the space | interval of the 1st pulse from a several light source, and the 2nd pulse following this, The any one of Claim 1 to 3 characterized by the above-mentioned. The position detection system according to claim 1. A sensor that receives the light pulse and detects the timing of the light pulse;
Based on the timing, a control unit that detects the position of the device on the screen on which the image is displayed;
A transmitter for transmitting a signal representing the position;
An indicator having
A receiver that receives a signal representing the position from the transmitter;
A plurality of light sources that project light pulses at a specific timing for each light source, with respect to an area obtained by dividing the screen into a plurality of parts,
An image display device comprising:
A position detection system comprising:   6. The position detection system according to claim 1, wherein a plurality of the indicators are provided. A position detection method in a position detection system, comprising:
A sensor provided in the indicator receives the light pulse and detects the timing of the light pulse;
A transmitter provided in the indicator transmits a signal representing the timing;
A reception unit included in the image display device receives a signal representing the timing from the transmission unit;
A plurality of light sources included in the image display device projecting light pulses at a timing specific to each light source with respect to an area obtained by dividing the screen into a plurality of areas;
A control unit provided in the image display device detects a position of the indicator on the screen on which an image is displayed based on a signal representing the timing; and
A position detection method comprising:

Images