JPH05181605A - Projection display device with coordinate reading function and its display screen and display - Google Patents

Abstract

PURPOSE:To automatically secure the correspondence between a screen coordinate system and an image coordinate system. CONSTITUTION:A projector 6 projects the image on a display screen 1. When a point is pointed on the screen 1 by a position pointer 2, a coordinate calculating means 3 calculates the coordinates of the pointed point. The 1st and 2nd photodetecting means 4 and 5 provided on the screen 1 detect the light of the images and output the detection signals. The 1st and 2nd image position storage means 7 and 8 store the image position signals xpos and ypos sent from the projector 1 when the detection signals are inputted. A coordinate transforming means 9 secures the correspondence between a screen coordinate system and an image coordinate system and performs the transformation of coordinates based on the coordinates of both means 4 and 5 shown on the screen 1 and the image coordinates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device with a coordinate reading function, which has a function of displaying display information input from an external device such as a computer on a screen and outputting the position on the screen to the external device. It is a thing.

[0002]

2. Description of the Related Art Conventionally, there is known a display device-integrated coordinate reading device for directly pointing a displayed image and inputting its position. As a device similar to this device, there is a device that uses a coordinate reading device as a display screen to project and display an image on the display screen, and reads the coordinates of the position by pointing on the screen.

For example, as shown in FIG. 10, the tablet 101 which is the coordinate reading plate of the coordinate reading device is used as a display screen, and image information output from the computer 110 is projected and displayed on the tablet 101 by the projection device 106. On the other hand, when the position pointer 102 points on the tablet 101, the coordinates of the point pointed are calculated by the coordinate calculation means 103 and output to the computer 110.

At this time, generally, the coordinate system of the coordinate reading device and the coordinate system of the displayed image do not match, so that the computer needs to make correspondence between the tablet coordinate system and the image coordinate system by a program. .. This relationship is shown in FIG.
Explained by. The coordinate system of the coordinate reading device is generally fixed to the tablet 101. In the figure, this coordinate system is represented by xoy. The scale on the coordinate axis is generally predetermined in units of mm or inch, which are units of length.

On the other hand, the coordinate system of the image 111 displayed on the tablet 101 is a coordinate system defined for the displayed image 111 and has no relation to the coordinate system of the coordinate reading device. For example, when the tablet 101 is tilted as shown in the figure, the directions of the coordinate axes of the two do not match. Further, the size of the image 111 can be changed depending on the distance between the tablet 101 as a screen and the projection device 106, and the position where the image 111 is displayed is also free, so that the scale of the coordinate axis and the origin of the coordinate axis are also set. It will not match.

An example of an application of such a device is an application in which the position indicator 102 traces on the tablet 101 and displays it as a locus. When used in such an application, it is obvious that the locus cannot be displayed at the position designated by the position indicator unless the coordinate system of the coordinate reading device and the coordinate system of the image match.

Therefore, in the conventional application, the display position and the size of the image 111 on the tablet 101 are measured in advance, and the information is given to the computer program so that the coordinate system of the coordinate reading device and the coordinate system of the image are set. It was converting. For example, the positions in the coordinate system of the coordinate reading device of points whose positions in the image coordinate system are determined, such as points O and A on the image shown in FIG. 11, are measured. By taking correspondence between the two points, it is possible to take correspondence regarding scaling, rotation, and parallel movement of both coordinate systems.

[0008]

However, the image on the screen is not always fixed, and it is sometimes desired to move or enlarge the image.
Moreover, it is possible that the user may unintentionally move during use.
The conventional device has a problem that it is very difficult to use because it is necessary to take the above-mentioned measures one by one in such a case. There has been a demand for a projection display device in which the position of the image with respect to the coordinate reading device is automatically made to correspond, and the coordinate system of the coordinate reading device and the coordinate system of the image always correspond.

The present invention has been made in order to meet such a demand, and its first object is to establish a coordinate system of a screen for displaying an image (equal to the coordinate system of a coordinate reading device in the prior art). It is to realize a projection display device with a coordinate reading function having a function of automatically associating with a coordinate system of a displayed image. A second object of the present invention is to realize a display screen used for constructing such a projection display device with a coordinate reading function.

A third object of the present invention is to realize a display device used to construct such a projection display device with a coordinate reading function.

[0011]

In order to solve the above problems, in the first aspect of the present invention, a display screen for displaying a projected image and coordinates in a screen coordinate system set on the display screen are calculated. A coordinate calculating means for projecting, a projection device for projecting a display image on a display screen,
Projection is performed by first and second light detecting means provided on the display surface of the display screen and separated from each other and detecting light emitted from the projection device, and by detecting the first and second light detecting means. A first memory for storing the positions of these light detecting means in the image coordinate system based on a display signal generated by the device.
And the second image position storage means, and based on the image positions stored in these first and second image position storage means, one of the coordinates in the screen coordinate system and the coordinates in the image coordinate system in the other coordinate system. The projection display device with the coordinate reading function is configured by providing the coordinate conversion means associated with the coordinates.

[0012]

In the projection display device with the coordinate reading function configured as described above, when the projection device projects an image on the display screen, the projection device projects the first and second light detecting means provided on the display screen. Detect light.
Since the display signal at the detected time represents the position of these light detecting means in the image coordinate system,
The first and second image position storage means store the position. Since the coordinates of the light detecting means in the screen coordinate system are predetermined, the coordinates of the screen coordinate system and the image coordinate system at the two points can be associated with each other. The coordinate conversion means associates one of the coordinates in the screen coordinate system and the coordinates in the image coordinate system with the coordinates in the other coordinate system based on the coordinates in the two coordinate systems. Since these processes are automatically performed while the image is displayed, the coordinate system of the screen displaying the image and the coordinate system of the displayed image can be automatically associated with each other.

[0013]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram of a projection display device with a coordinate reading function according to this embodiment. In FIG. 1, reference numeral 1 is a display screen on which an image projected is displayed. A position indicator 2 indicates the reading position on the display screen 1. Further, 3 is a coordinate calculating means for calculating coordinate values based on a signal generated by the connection between the display screen 1 and the position indicator 2. Functionally, the part composed of the display screen 1, the position indicator 2, and the coordinate calculating means 3 is functionally equivalent to the coordinate reading device. Various configurations of the coordinate reading device have been proposed, and the present invention can be realized with any configuration. Detailed description of this part is omitted. The coordinate system of the coordinates read on the screen 1 is called a "screen coordinate system".

The display screen 1 has a first light detecting means 4
And a second light detecting means 5 are provided. The two are provided at positions distant from each other and at a position where an image projected from the projection device 6 described later is displayed, and the position is predetermined by coordinate values in the screen coordinate system. The first and second light detecting means 4 and 5 output the detection signal det1 or det2 when receiving light having a certain intensity or more. Since the purpose is to detect the light of the image projected from the projection device 6 to be described later, a threshold value for detection is set so that only this light is detected and external light is not detected. ..

Reference numeral 6 is a projection device for projecting image information input from the computer 10 onto the display screen 1. A projection device of either the raster scan system or the random scan system may be used, but the display position signal xp is externally provided.
It has a function of outputting os and ypos. Note that, hereinafter, the coordinate system in which the display position signals xpos and ypos are expressed is referred to as an “image coordinate system”.

Reference numeral 7 is a first image position storage means, and 8 is a second image position storage means. Detection signals det1 and det2 output from the first and second light detection means 4 and 5, respectively.
, And the display position signal xpos, y at that time
Remember pos. The projection device 6 and the first and second image position storage means 7 and 8 will be described in more detail with reference to FIG. First, the projection device 6 is schematically shown as a horizontal display position counter 61, a vertical display position counter 62, and a display element 6.
3, a display control device 64. If the projection device 6 is a raster scan type projection device, the horizontal display position counter 61 and the vertical display position counter 62 are used to determine the position on the display element 63, and the position is turned on / off by the image data dd. Display the image. Therefore, the output of the horizontal display position counter 61 is the horizontal coordinate xpos in the image coordinate system, and similarly, the output of the vertical display position counter 62 is the vertical coordinate ypos in the image coordinate system.

The first image position storage means 7 is composed of an X1 register 71 and a Y1 register 72, and de
By inputting t1, xpo is stored in the X1 register 71.
ys is stored in the Y1 register 72. The second
The image position storage means 8 is composed of an X2 register 81 and a Y2 register 82. By inputting det2, xpos is stored in the X2 register 81 and ypos is stored in the Y2 register 82. The values of the display position signals xpos and ypos stored here indicate the coordinates in the image coordinate system of the first and second light detecting means.

The description of the configuration will be continued with reference to FIG. 1 again.
Reference numeral 9 denotes a coordinate conversion means, which is the coordinates of the first and second light detection means 4 and 5 in the screen coordinate system and the image coordinate system stored in the first and second image position storage means 7 and 8. On the basis of the coordinates in (1), one of the coordinates in the screen coordinate system and the coordinates in the image coordinate system is associated with the coordinates in the other coordinate system.

In order to make the description more concrete, the association between the coordinates in the screen coordinate system and the coordinates in the image coordinate system is "converting the coordinates in the screen coordinate system into the coordinates in the image coordinate system". To do. With this definition, the coordinate calculation means 9 is stored in the screen coordinate system of the first and second light detection means 4 and 5 and in the first and second image position storage means 7 and 8. It can be said that the coordinates in the screen coordinate system are converted into the coordinates in the image coordinate system based on the coordinates in the image coordinate system.

Before describing the operation here, the coordinate conversion process performed by the coordinate conversion means 9 will be described.
FIG. 3 is an explanatory view showing a screen coordinate system and an image coordinate system. The coordinate axis xoy indicates the coordinate axis of the screen coordinate system, and the coordinate axis XOY indicates the coordinate axis of the image coordinate system. The screen coordinate system is rotated by the angle θ. This indicates that the display screen is rotated with respect to the display image.

A point P1 is a position where the first light detecting means 4 is provided, and a point P2 is a position where the second light detecting means 5 is provided. The point P is an arbitrary input point. Point P1
And a point P2 in the screen coordinate system P1 (x1, y
1) and P2 (x2, y2) are known. Coordinates P1 (X1, Y1) in those image coordinate systems are stored in the first image position storage means 7, and P2 (X2, Y2) are stored in the second image position storage means 8. These are detected and known during operation. The point P is designated by the position indicator 2 so that the coordinate P in the screen coordinate system
(X, y) is calculated.

The coordinate conversion processing performed here is the coordinate P1.
(X1, y1), P2 (x2, y2), P1 (X1, Y
1) and P2 (X2, Y2), the coordinate P (x, y) of the input point P in the screen coordinate system is coordinate P in the image coordinate system.
It is to convert to (X, Y). This process is accomplished by three processes of enlargement / reduction of the coordinate system, rotation and translation. This processing is performed by the following steps, for example.

First, the coordinate system xoy is enlarged / reduced, and the coordinate system which is made to coincide with the scale of the coordinate system XOY is defined as qor. (Not shown) Then, in this coordinate system, the following definition is made. P (q, r) Coordinates of point P after enlargement / reduction P1 (q1, r1) Coordinates of point P1 after enlargement / reduction G G Scale of coordinate system xoy is coordinate system X
Enlargement ratio for enlarging / reducing to the OY scale The reduced / enlarged coordinates of the point P and the point P1 are obtained by (Equation 1) to (Equation 5). (In the following equation, * is a multiplication symbol, / is a division symbol, ** is a power symbol, sqrt ().
Is a function for obtaining the square root. ) Q = G * x (Equation 1) r = G * y (Equation 2) q1 = G * x1 (Equation 3) r1 = G * y1 (Equation 4) where G = sqrt ((X2-X1) ** 2+ (Y2-Y1) ** 2) / (x2-x1) (Equation 5) Next, the coordinate system qor is rotated around the origin o to obtain the coordinate system X.
A soot is defined as a coordinate system that matches the OY direction. (Not shown) Then, in this coordinate system, the following definition is made.

P (s, t) Coordinates of the point P after rotation P1 (s1, t1) Coordinates of the point P1 after rotation The rotated coordinates of the point P and the point P1 are the following (formula 6) to (formula 1).
2) required. s = (q-r * tan θ) * cos θ (Equation 6) t = (r / cos θ) + (q-r * tan θ) * sin θ (Equation 7) s1 = (q1-r1 * tan θ) * cos θ (Equation 8) ) T1 = (r1 / cos θ) + (q1-r1 * tan θ) * sin θ (formula 9) where cos θ = (X2-X1) / sqrt ((X2-X1) ** 2+ (Y2-Y1) ** 2 ) (Formula 10) sin (theta) = (Y2-Y1) / sqrt ((X2-X1) ** 2+ (Y2-Y1) ** 2) (Formula 11) tan (theta) = (Y2-Y1) / (X2-X1) ( (Equation 12) Further, the coordinate system sot is moved in parallel to match the coordinate system XOY. The translated coordinates are obtained by the following (Equation 13) and (Equation 14).

X = s + (X1-s1) (Equation 13) Y = s + (Y1-t1) (Equation 14) As described above, the coordinate P (x, y) of the input point P in the screen coordinate system is an image. It is converted into coordinates P (X, Y) in the coordinate system. Next, the operation will be described. The description of the operation of the part as the coordinate reading device, which is composed of the display screen 1, the position indicator 2, and the coordinate calculating means 3, is omitted, and here, the detection of the image position will be mainly described.

In this embodiment, the projection device 6 is described as a raster scan type. This system is shown in Figure 4.
The image 11 is displayed by the scanning line 11a as shown in FIG. Here, for the sake of explanation, the scanning line 11a is sequentially scanned from the bottom to the top of the image. This order is not general, but it is assumed in this way in the context of the coordinate transformation process already described.

In FIG. 4, the third scanning line from the bottom crosses over the first light detecting means 4, and the sixth scanning line from the bottom crosses over the second light detecting means 5. As the scanning line crosses over it, each photodetecting means detects the light of the scanning line and outputs a detection signal. The above operation will be described with reference to the timing chart of FIG. 5 and the configuration diagram of FIG. The horizontal display position counter 61 outputs the horizontal display position signal xpos, and the vertical display position counter 62 outputs the vertical display position signal yp.
os is sequentially output to scan the image. The display position signal ypos in the vertical direction is ypos1, ypos in order from the bottom.
2, and the horizontal display position signal xpos is xpos1, x in order from the left at the determined ypos.
It is output while increasing as pos2 .... Display element 6
It is assumed that 3 emits light when the image data dd is 1, and assuming that the image data dd is always 1, scanning lines in the light emitting state are sequentially scanned from the bottom on the screen by the above operation. Will be displayed.

When the image and the light detecting means are in the relationship shown in FIG. 4, ypos3 is output, and the light from the scanning line hits the first light detecting means 4 at the time when some xpos has advanced, and the first light detecting means 4 is detected. The light detecting means 4 outputs a detection signal det1. In FIG. 5, xpos at that time is shown as xpos5. Similarly, ypos is ypos6 and xpos is x.
At pos25, the second light detecting means 5 detects the light from the scanning line and outputs the detection signal det2.

The first image position storage means 7 detects the detection signal de.
By inputting t1, xpos at that time
= Xpos5 and ypos = ypos3 are stored. The second image position storage means 8 receives the detection signal det2, so that xpos = xpos2 at that time.
5, ypos = ypos6 is stored. The values of xpos and ypos stored in this way become the coordinates in the image coordinate system of the first and second light detecting means.

In the above description, the case where the image data dd is always 1 has been described. However, even when a general image is displayed, light may hit the light detecting means. The coordinates in the image coordinate system can be detected. When the image data dd is 0, it cannot be detected, but in that case, the content of the image position storage means is not updated, and the previously detected value remains unchanged. There is no inconvenience to the subsequent processing.

Further, it is possible to increase the number of the light detecting means and the image position storing means corresponding to the light detecting means, identify the light detecting means to which the light is applied, and select two of the light detecting means. .. The processing for performing coordinate conversion by the coordinate conversion means 9 based on the coordinates of the light detection means in the screen coordinate system and the coordinates stored in the image position storage means is as already described. These processes can be easily realized by, for example, digital arithmetic processing by a program of a microprocessor.

Next, some other modifications of the above embodiment will be described. First, in the above embodiment, the association between the coordinates in the screen coordinate system and the coordinates in the image coordinate system performed by the coordinate conversion means 9 is described as "converting the coordinates in the screen coordinate system into the coordinates in the image coordinate system". did.
However, this is just an example, and other associations are possible. For example, it is conceivable to convert the coordinates in the image coordinate system into the coordinates in the screen coordinate system, or to convert into the coordinates of a third coordinate system different from both coordinate systems. The type of association may be determined by the application.

The image coordinate system and screen coordinate system in the above embodiment are not limited to those described above. For example, in a raster scan type projection apparatus, vertical scanning is normally performed from top to bottom. Therefore, the coordinates ypos in the image coordinate system are opposite to the above description in the positive and negative directions. However, even in such a case, it is possible to make the correspondence between the screen coordinate system and the image coordinate system by appropriate processing, and convert the coordinate in the screen coordinate system into the coordinate in the image coordinate system in the same manner as above. be able to.

Although the raster scan type projection apparatus has been described in the above embodiment, the display position signals xpos and yp are also externally output to the random scan type projection apparatus.
The same operation can be performed by adding a function for outputting os. Further, some of the constituent elements of the above-described embodiments can be replaced by a computer and its program, and thus each element does not have to be clearly separated. For example, the first and second image position storage means 7 and 8 can be provided with an interface with the projection device 6 in a computer, and the storage section can be a computer memory. Similarly, the coordinate conversion means 9 can be replaced with a computer program by providing an interface on the computer. Various concrete configurations are conceivable.

Next, an embodiment of the second invention will be described. In the embodiment of the first aspect of the invention, the predetermined purpose cannot be achieved if the portion of the displayed image that is associated with the light detecting means is not always emitting light. The present invention has been improved to solve this problem. FIG. 6 shows a block diagram of a projection display device with a coordinate reading function according to the second invention. In FIG. 6, a reference image generating means 12 is newly provided. The reference image generating means is provided with an instruction switch 12a, and when this switch is pressed, the reference image data gdr is output to the projection device 16. The reference image data gdr is a signal that causes a portion of the image related to the light detecting means to emit light. Simply, the entire image may be made to emit light.

The projection device 16 also projects the reference image data gdr in addition to the image data gd from the computer 10. Image data gd and reference image data g
It may be switched with dr by an instruction from the instruction switch 12a, or may be ORed. Other parts are first
Is similar to the embodiment according to the invention. With such a configuration, the reference image can be arbitrarily displayed, so that the first and second light detection means 4 and 5 can detect the light of the image and achieve the predetermined purpose. become able to.

In the above description, the reference image generating means 12
Are provided independently, but they may be generated from the computer 10. Alternatively, the reference image gdr may be periodically generated, and the switch 12a may be omitted to achieve automation. Next, examples of the third and fourth inventions will be described. The first and second inventions relate to the projection display device with the coordinate reading function, whereas the third and fourth inventions relate to the display screen for constituting this device.

FIG. 7 shows a block diagram of the display screen according to the third invention, and FIG. 8 shows a block diagram of the display screen according to the fourth invention. In any structure, the elements of the respective parts are the same as those of the embodiment according to the first invention. The display screen according to the third invention is provided with a configuration for calculating coordinates and first and second light detecting means 4 and 5. The means for projecting the image, the means for storing the image position of each light detection means, and the means for converting the coordinates must be provided outside. The configuration provided outside can be realized by adding a simple interface to the computer except the means for projecting an image.

The present invention is significant in that a projection display device with a coordinate reading function can be configured by simply adding a simple device to the coordinate reading device when an environment for display has already been prepared. It is a thing. The display screen according to the fourth invention is for reducing the load on the external device side as compared with the third invention. A means for projecting an image and a computer may be connected to the outside. From the means for projecting the image, the display position signal xpos,
It is designed to input ypos.

Next, an embodiment of the fifth invention will be described. The third and fourth aspects of the invention relate to a display screen for constructing a projection display device with a coordinate reading function, while the fifth aspect of the invention relates to a display device. FIG. 9 shows a block diagram of a display device according to the fifth invention. The elements of each part are similar to those of the first embodiment. The present invention relates to a display device used in combination with the display screen according to the third invention. By comparing with the first invention in combination with the third invention, it can be understood that a projection display device with a coordinate reading function can be configured by this display device.

[0041]

As described above, according to the present invention, an image is displayed on a display screen corresponding to a tablet of a coordinate reading device, and a device for indicating an image and reading the coordinates detects light of the image. Means, image position storage means for storing the position of the light detection means in the image coordinate system, and coordinate conversion means for associating the screen coordinate system with the image coordinate system. It is configured such that one of the coordinate in the screen coordinate system and the coordinate in the image coordinate system is associated with the coordinate in the other coordinate system, based on the coordinate in the image coordinate system stored in the image position storage means.

Therefore, it is possible to realize a projection display device with a coordinate reading function that can automatically associate the coordinates read on the screen with the coordinates of the image coordinate system.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a projection display device with a coordinate reading function according to a first invention.

FIG. 2 is a detailed configuration diagram of the projection device and the first and second image position storage means of the projection display device with the coordinate reading function according to the first invention.

FIG. 3 is an explanatory diagram of correspondence between a screen coordinate system and an image coordinate system.

FIG. 4 is an explanatory diagram of an image display method.

FIG. 5 is a timing chart of signals of respective parts of the projection display device with a coordinate reading function according to the first invention.

FIG. 6 is a configuration diagram of a projection display device with a coordinate reading function according to a second invention.

FIG. 7 is a configuration diagram of a display screen according to a third invention.

FIG. 8 is a configuration diagram of a display screen according to a fourth invention.

FIG. 9 is a configuration diagram of a display device according to a fifth invention.

FIG. 10 is a configuration diagram of a conventional projection display device with a coordinate reading function.

FIG. 11 is an explanatory diagram of a usage state of a conventional projection display device with a coordinate reading function.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 display screen 2, 102 position indicator 3, 103 coordinate calculation means 4 first light detection means 5 second light detection means 6, 106 projection device 7 first image position storage means 8 second image position storage means 9 coordinate conversion means 10, 110 computer 12 reference image generation means 61 horizontal display position counter 62 vertical display position counter 63 display element 64 display control device det1, det2 detection signal xpos, ypos display position signal

Claims (5)

[Claims] 1. A display screen for displaying a projected image, coordinate calculation means for calculating coordinates of a designated position on a screen coordinate system set on the display screen, and an image displayed on the display screen. A projection device for projecting light and a part of a display surface of the display screen, which are spaced apart from each other, and which detects light emitted from the projection device.
Of the light detection means and the second light detection means, and the first light detection means detects the first light detection means, and the first light detection means detects the first light detection means. A first image position storage means for storing the position of the first light detection means, and a display signal generated by the projection device by being detected by the second light detection means,
Second image position storage means for storing the position of the second light detection means in the image coordinate system; and the first and second image position storage means.
Coordinate conversion means for associating one of the coordinates in the screen coordinate system calculated by the coordinate calculation means and one of the coordinates in the image coordinate system with the coordinates in the other coordinate system based on the image position stored in the image position storage means. A projection display device with a coordinate reading function, comprising: 2. The projection display device with a coordinate reading function according to claim 1, further comprising a reference image generating unit that outputs a reference image projected to be detected by the first light detecting unit and the second light detecting unit. .. 3. A display screen which constitutes a projection display device with a coordinate reading function together with a display device, the display screen for displaying a projected image, and an instruction on the screen coordinate system set on the display screen. Coordinate calculating means for calculating the coordinates of the selected position and outputting the coordinates to an external device, and detecting light emitted from the externally provided display device provided separately from each other on a part of the display surface of the display screen. A display screen of a projection display device with a coordinate reading function, comprising: a first light detecting means and a second light detecting means for outputting a detection signal to the outside. 4. A display screen which constitutes a projection display device with a coordinate reading function together with a display device, the display screen for displaying a projected image, and an instruction on a screen coordinate system set on the display screen. Calculating means for calculating the coordinates of the selected position, and first light detection provided on a part of the display surface of the display screen apart from each other to detect light emitted from the display device provided outside. Means and second light detecting means, and the first light detecting means in the image coordinate system set in the display image based on the display signal generated by the display device by detection by the first light detecting means. A first image position storing means for storing the position of the means, and a second image detecting means for detecting the position of the means in the image coordinate system based on a display signal generated by the projection device. Second image position storage means for storing the position of the second light detection means, and a screen calculated by the coordinate calculation means based on the image positions stored in the first and second image position storage means. A display screen of a projection display device with a coordinate reading function, comprising: a coordinate conversion unit that associates one of the coordinates in the coordinate system and the coordinates in the image coordinate system with the coordinates in the other coordinate system. 5. A coordinate calculation means for calculating coordinates of a designated position on a screen coordinate system set on the display screen, and a part of a display surface of the display screen, which are provided separately from each other, and A display device which constitutes a projection display device with a coordinate reading function together with a display screen having first light detecting means and second light detecting means for detecting emitted light and outputting a detection signal to the outside, the display comprising: A projection device for projecting a display image on a screen;
A first image position for storing the position of the first photodetector in the image coordinate system set for the display image based on the display signal generated by the projection device by the detection signal output by the photodetector. A second image that stores the position of the second light detection unit in the image coordinate system based on the display signal generated by the projection device by being detected by the storage unit and the second light detection unit. Based on the position storage means and the image positions stored in the first and second image position storage means, one of the coordinates in the screen coordinate system and the coordinates in the image coordinate system calculated by the coordinate calculation means is the other. A display device of a projection display device with a coordinate reading function, comprising: a coordinate conversion unit that associates the coordinate with the coordinate in the coordinate system.