JP2002351612A - Coordinate input device, its control method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coordinate input device capable of outputting coordinates at a low cost, with high accuracy and high resolution without lowering a coordinate detection sampling rate, its control method and a program. SOLUTION: An optical signal from an optical spot having a plurality of detection areas, in which detecting operations in the respective detection areas are independently controlled is detected by a linear sensor. A detecting operation in a first detection area among the plurality of detection areas is performed for first prescribed time and presence/absence of the optical signal from the optical spot is judged based on a detection result from the first detection area. When the optical signal is judged to exist, the detecting operation in the first detecting area is further performed for second prescribed time. On the other hand, when no optical signal is judged to exist, a detecting operation is performed other detection areas except the first one for the first prescribed time, the presence/absence of the optical signal from the optical spot is judged based on the detection result from the first detection area and a detecting operation in the detection area in which the optical signal is judged to exist is further performed for the second prescribed time. And a coordinate value corresponding to the optical spot is calculated based on the detection result from the detection area in which the optical signal is judged to exist.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device for generating a light spot by irradiating light from a pointing tool onto a coordinate input screen and generating coordinates corresponding to the light spot, a control method therefor, and a program. Things.

[0002]

2. Description of the Related Art As a conventional coordinate input device, a light spot on a screen is imaged using a CCD area sensor or a linear sensor, and image processing using barycentric coordinates or pattern matching is performed to calculate coordinate values. An output device and a device using a position detecting element called a PSD (an analog device capable of obtaining an output voltage corresponding to the position of a spot) are known.

[0003] For example, Japanese Patent Publication No. 7-76902 discloses an apparatus for detecting a coordinate by imaging a light spot with a parallel beam of visible light with a video camera and simultaneously transmitting and receiving a control signal with infrared diffused light. ing. Japanese Patent Application Laid-Open No. 6-274266 discloses an apparatus for detecting coordinates using a linear CCD sensor and a special optical mask.

On the other hand, Japanese Patent Publication No. 2503182 discloses that
A configuration using a PSD and a method of correcting output coordinates are disclosed.

[0005] In recent years, the brightness of the screen of a large screen display has been improved, and it has become possible to sufficiently use it even in a brightly illuminated environment, and the demand is expanding. The coordinate input device is increasingly required to be resistant to disturbance light so that it can be used in an environment combined with such a large-screen display. Also, in recent years, devices using infrared rays as wireless communication means have been increasing, and disturbance light has been increasing for both infrared rays and visible light. Therefore, resistance to disturbance light is one of the important characteristics of the device. It is.

However, the aforementioned Japanese Patent Publication No. 7-76902
As can be seen from JP-A-6-274266 and JP-A-6-274266, in a device using a conventional CCD sensor, disturbance light can be suppressed only by an optical filter. On the other hand, as disclosed in Japanese Patent Publication No. 2503182, P
In an apparatus using SD, the influence of disturbance light can be suppressed by frequency-modulating the light intensity and synchronously detecting this modulated wave. Therefore, when used in combination with an optical filter, it has a strong characteristic against disturbance light. ing. However, this kind of coordinate input device has a problem in principle in terms of improvement in resolution. In other words, since the dynamic range of the sensor output voltage directly corresponds to the input range,
For example, when the whole is decomposed into 1000 coordinates, an S / N ratio of at least 60 dB or more is required. further,
As described in Japanese Patent Publication No. 2503182, digital correction of a linearity error is essential, so that a high-precision analog circuit, a multi-bit AD converter, and an arithmetic circuit are required. Further, since the S / N ratio of the sensor output signal depends on the amount of light and the sharpness of the light spot, suppression of disturbance light alone is not sufficient, and a bright and highly accurate optical system is also required. For this reason, the device itself is very expensive and large.

Further, as a technique for increasing the resolution by using a CCD sensor, Japanese Patent Publication No. 7-76902 discloses that a plurality of video cameras are used at the same time. become. Also,
In the case of a single video camera having a large number of pixels, the size and cost are further increased as compared with the case of using a plurality of cameras. Further, in order to achieve a resolution higher than the number of pixels by image processing, high-speed processing of enormous image data is required, which is very large and expensive for real-time operation.

In Japanese Patent Application Laid-Open No. Hei 6-274266, a high resolution is obtained by a special optical mask and signal processing.
If the N ratio can be secured, high resolution can be achieved. However, in reality, the image is linear in a linear sensor,
Since it cannot be separated from disturbance light in a plane as compared with an area sensor serving as a point image, there is a problem that it is easily affected by disturbance light and is practical only in a special environment where disturbance light is small.

In view of the above, a coordinate input device which is hardly affected by disturbance light, has high accuracy, and is relatively inexpensive is disclosed in
No. 1-219253, JP-A-2000-112644
Also, a coordinate input device using a photoelectric conversion element and an electronic shutter function as disclosed in Japanese Patent Application Laid-Open No. H10-209,086 is disclosed.

[0010]

Various coordinate input devices are known as shown in the prior art. However, from the viewpoint of the coordinate calculation accuracy or the resolution, as described above, it is expensive and large. There is a problem that it becomes something.

Further, in the case of a coordinate input device using a photoelectric conversion element and an electronic shutter function as disclosed in JP-A-11-219253 and JP-A-2000-112644, a writing instrument is provided. The light emitting member such as the LED blinks, and the electronic shutter is operated in synchronization with the blinking, and a signal when the light emitting member is turned on and a signal when the light emitting member is not turned on are respectively accumulated by the photoelectric conversion sensor, and the accumulated lighting is performed. By outputting a difference signal between a signal at the time of lighting and a signal at the time of non-lighting, a signal of disturbance light is removed, and only a light signal of the light emitting member is purely extracted. Further, the coordinate input device employs an optical system that forms an image of the light of the light emitting member on a light receiving surface of a photoelectric conversion sensor, but focuses on purpose so that the light is incident on a plurality of photoelectric conversion sensors. The configuration is such that the coordinate calculation resolution is improved by performing a shift (out-of-focus state) and performing calculations using output signals of a plurality of photoelectric conversion sensors on which light has entered.

In other words, since the light of the light spot is incident on the plurality of pixels in a deliberately blurred state, of the plurality of photoelectric conversion sensors, the photoelectric concentration sensor is the most concentrated. With the conversion sensor at the center, the left and right photoelectric conversion sensors output weaker optical signals as the distance from the center photoelectric conversion sensor increases. If the signal output from each of the plurality of photoelectric conversion sensors is plotted on the horizontal axis and the output signal level of each photoelectric conversion sensor is plotted on the vertical axis, the signal from the central photoelectric conversion sensor becomes the peak level. As
A mountain-shaped signal waveform is obtained (see FIG. 13 as an example). By calculating the position of the center of gravity from the signal waveform of the chevron, it is possible to maintain the coordinate calculation resolution at a certain level or more even with a relatively small number of photoelectric conversion sensors (the number of pixels).

However, in order to ensure higher-resolution coordinate calculation performance with such a configuration, coordinate calculation is performed using more information of the photoelectric conversion sensor (that is, coordinate calculation is performed).
Need to be more defocused).
In this case, since the output signal of the photoelectric conversion sensor whose distance from the photoelectric conversion sensor at which the signal level naturally peaks becomes larger becomes smaller, the signal S of the photoelectric conversion sensor becomes smaller.
It is necessary to sufficiently consider / N. In order to obtain signal reliability, the amount of light emission per unit time of the light emitting means built in the writing instrument is increased, or the light conversion sensor side is set to a longer integration time, which is a time for capturing light. There is a need.

The former method of increasing the amount of light emitted by the light-emitting means per unit time has, of course, a limit due to the restriction of the light-emitting means, and also leads to an increase in power consumption, and the consumption of batteries and the like built in the writing instrument is reduced. Become intense, increase running costs, or charge system becomes an indispensable configuration, greatly affecting the weight and shape as a writing instrument,
Causes a major obstacle in practical use.

On the other hand, the latter method of increasing the integration time, which is the time for capturing light, causes a decrease in the coordinate sampling rate. That is, for example, when a sufficiently reliable signal can be obtained with an integration time of about 20 msec, the coordinate output can be performed 50 times per second without considering the coordinate calculation time. If the integration time is set to 40 msec in order to achieve more resolution and obtain a reliable signal in order to realize the resolution, the coordinate sampling rate is 25 times / sec, which is extremely degraded in performance.

As a method of improving the resolution and accuracy, a method of increasing the number of photoelectric conversion sensors is also effective. That is, for example, a distance of 1 meter is measured by 64 photoelectric conversion sensors (64 pixels) or 128 pixels (12 pixels).
It is self-evident that the resolution of the latter is naturally higher depending on whether the measurement is performed with 8). However, such a configuration naturally increases the number of photoelectric conversion elements, and thus causes an increase in cost or a need to improve the drive processing capability of the photoelectric conversion sensor. A new problem will arise.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is a coordinate input device capable of outputting coordinates with high accuracy and high resolution at low cost without lowering the sampling rate for calculating coordinates. And its control method,
The purpose is to provide the program.

[0018]

A coordinate input device according to the present invention for achieving the above object has the following arrangement.
That is, a coordinate input device that irradiates the coordinate input screen with light from the pointing tool to generate a light spot and generates coordinates corresponding to the light spot, and has a plurality of detection areas. Detecting means for detecting an optical signal from the light spot, wherein the detecting operation is independently controlled, and driving means for executing a detecting operation in a first detecting area of the plurality of detecting areas for a first predetermined time Determining means for determining the presence or absence of an optical signal from the light spot based on a detection result from the first detection area obtained by the driving means; and determining that the optical signal is present. A first control unit for controlling the driving unit so as to further execute a detection operation of the first detection region for a second predetermined time; and the first detection unit, wherein the determination unit determines that there is no optical signal. Other detection area other than area A second control unit that executes the driving unit and the determination unit, and controls the driving unit to further execute a detection operation of a detection region determined to have the optical signal for a second predetermined time; And a coordinate calculation means for calculating a coordinate value corresponding to the light spot based on a detection result from a detection area determined to have the optical signal by the determination means.

Preferably, the determination means determines that there is an optical signal from the light spot when a detection result from the first detection area is equal to or more than a predetermined value.

Preferably, the detecting means is physically composed of a plurality of sensors, and the plurality of detection areas correspond to the detection areas of each of the plurality of sensors.

Preferably, the detecting means includes one sensor, and the plurality of detection areas correspond to each area group obtained by dividing the detection area of the sensor into a plurality of groups.

Preferably, the first detection area is:
It corresponds to the central area on the coordinate input screen.

Preferably, the apparatus further comprises selection means for selecting the first detection area based on an output interval of a calculation result of the coordinate calculation means.

A control method of a coordinate input device according to the present invention for achieving the above object has the following configuration. That is,
A method for controlling a coordinate input device that irradiates a coordinate input screen with light from a pointing tool to generate a light spot and generates coordinates corresponding to the light spot, comprising: detecting a light signal from the light spot. A driving step of executing a detection operation in a first detection area for a first predetermined time among a plurality of detection areas whose operations are independently controlled, and a detection result from the first detection area obtained by the driving step. A determination step of determining the presence or absence of an optical signal from the light spot based on the determination based on the determination of the presence of the optical signal; and a detection operation of the first detection area is further performed for a second predetermined time. When the first control step of controlling the driving step and the determining step determine that there is no optical signal, the driving step and the determining step are performed on other detection areas other than the first detection area. And the light A second control step of controlling the driving step so as to further execute a detection operation of the detection area determined to have the signal, and a detection area determined to have the optical signal by the determination step A coordinate calculation step of calculating a coordinate value corresponding to the light spot based on a detection result from the light spot.

A program according to the present invention for achieving the above object has the following configuration. That is, a program that causes a computer to control a coordinate input device that generates light spots by irradiating light from a pointing tool onto a coordinate input screen and generates coordinates corresponding to the light spots. Of a plurality of detection areas in which detection operations for detecting the optical signal are independently controlled, and a program code of a driving step for executing a detection operation in the first detection area for a first predetermined time, and the driving step obtains the program code. A program code for a determination step of determining the presence or absence of an optical signal from the light spot based on a detection result from the first detection area;
When the determination step determines that the optical signal is present, a program code of a first control step for controlling the driving step so as to further execute a detection operation of the first detection region for a second predetermined time; When it is determined that the optical signal does not exist, the driving step and the determining step are performed on other detection areas other than the first detection area, and the detection operation of the detection area determined to have the optical signal is performed. Based on a program code of a second control step for controlling the driving step so as to further execute the second predetermined time, and a detection result from a detection area determined to have the optical signal by the determination step. A program code for a coordinate calculation step for calculating a coordinate value corresponding to the light spot.

[0026]

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

First, the schematic configuration of the optical coordinate input device according to the present invention will be described with reference to FIG.

FIG. 1 is a diagram showing a schematic configuration of a coordinate input device according to the present embodiment.

The coordinate input device is roughly divided into an indicator 4 for forming a light spot 5 on a screen 10 as a coordinate input surface, and a coordinate detector 1 for detecting the position coordinates of the light spot 5 on the screen 10 and the like. Consists of FIG. 1 shows a screen 10 as an output device together with those configurations.
2 shows a projection display 8 for displaying an image, position coordinates, and the like.

The coordinate detector 1 includes a coordinate detection sensor unit 2 and
A controller 3 for controlling the coordinate detection sensor unit 2 and calculating coordinates, a light receiving element 6, a signal processing unit 7, and a nonvolatile memory 9 such as an EEPROM for storing various set values.
It is composed of Screen 10 of light spot 5
A control signal corresponding to the above coordinate position and the state of each switch of the indicating tool 4 described later is detected, and the information is communicated by the controller 3 to an external connection device (not shown).

The projection display device 8 includes an image signal processing unit 81 to which an image signal from a display signal source, which is an external connection device such as a host computer (not shown), is input, a liquid crystal panel 82 controlled by the image signal processing unit 81, Lamp 83, mirror 8
4. An illumination optical system including a condenser lens 85, and a projection lens 86 for projecting an image of the liquid crystal panel 82 onto the screen 10,
Can be displayed. Since the screen 10 has an appropriate light diffusing property in order to widen the observation range of the projected image, the light beam emitted from the pointing tool 4 is also diffused at the position of the light spot 5, and the position on the screen and A part of the light diffused at the position of the light spot 5 enters the coordinate detector 1 irrespective of the direction of the light beam.

With this configuration, by inputting character information and line drawing information on the screen 10 by the pointing tool 4 and displaying the information on the projection display device 8, it is as if "paper and pencil". In addition to enabling input / output of information in a relationship, it is configured such that input operations such as button operation and icon selection can be freely performed. <Detailed Description of Pointing Tool 4> FIG. 2 is a diagram showing a detailed configuration of the pointing tool of the present embodiment.

The pointing device 4 is a light emitting element 4 such as a semiconductor laser for emitting a light beam or an LED for emitting infrared light.
1, a light emission control unit 42 for driving and controlling the light emission, a power supply unit 44, operation switches 43A to 43D, a power supply unit 44 such as a battery, and a cap 46 made of a detachable translucent member that covers the light emitting element 41. And built-in. The light emission control unit 42 changes the state of the operation switches 43A to 43D.
Light emission control in which a control signal is superimposed is performed by ON (ON) / OFF (OFF) of light emission and a modulation method described later.

FIG. 3 is a diagram showing an operation mode of the pointing device of the present embodiment.

The switches A to D correspond to the switch 43A of FIG.
~ 43D. In FIG. 3, “light emission” corresponds to a light emission signal (coordinate signal), and “pen down” and “pen button” correspond to control signals.

The operator holds the pointing device 4 and holds the screen 1
Point its tip at zero. At this time, the switch 43A is arranged at a position where the thumb naturally touches, and when pressed, the light beam 45 is emitted. As a result, the light spot 5 is generated on the screen 10, and the coordinate signal starts to be output by a predetermined process. However, in this state, the pen down and pen button control signals are OFF. For this reason, on the screen 10, only the indication of the position indicated to the operator by the movement of the cursor or the switching of the highlight of the button is performed.

By pressing the switches 43C and 43D arranged at positions where the index finger and the middle finger naturally touch, the control signal of the pen down and the pen button becomes a signal superimposed on the light emission signal as shown in FIG. . That is, by pressing the switch 43C, a pen-down state is established, and screen control such as starting input of characters and line drawings and selecting and determining a button can be executed. Switch 43
By pressing D, the state of the pen button is established, and it is possible to correspond to another function such as calling a menu. This allows the operator to quickly and accurately draw characters and figures at any position on the screen 10 with one hand,
By selecting buttons and menus, it can be operated lightly.

A switch 4 is provided at the tip of the pointing device 4.
A switch 3B is provided and operates when the pointing tool 4 is pressed against the screen 10. The operator grips the pointing device 4 and touches the tip of the pointing device on the screen 10.
, A pen-down state is established, so that a natural pen input operation can be performed without performing extra button operations.

The switch 43A has a role of a pen button. Of course switch 43A without pressing on the screen
You can also move the cursor only by pressing. Actually, the operability and accuracy are much better when the characters and graphics are input directly from the screen than when the characters or figures are input from the screen. In the present embodiment, even if the user is away from the screen by using the four switches, or immediately before, a natural and comfortable operation can be performed, and the user can use the switch depending on the case. I have. Furthermore, if it is only for direct input (not used as a pointer), a diffused light source may be used instead of a light beam.
Can also be used.

Further, when two kinds of pointing tools 4 for proximity and remote use are used as described above, two or more persons operate simultaneously, or a plurality of pointing tools 4 having different attributes such as color and thickness are used. For this reason, the light emission control unit 42 is set to transmit a unique ID number together with a control signal. In accordance with the transmitted ID number, attributes such as the thickness and color of the drawn line are determined by software on the external connection device side, and the setting can be changed by a button or menu on the screen 10. Can be. For this operation, an operation button or the like may be separately provided on the indicating tool 4 to transmit a change instruction signal. For these settings, the state is maintained in the indicating tool 4 or the coordinate detector 1. It is also possible to configure so that attribute information, instead of the ID number, is transmitted to the externally connected device.

Further, such additional operation buttons can be set so that other functions, such as blinking of a display device, switching of a signal source, operation of a recording device, and the like, can be performed.
Further, by providing pressure detection means in one or both of the switches 43A and 43B, pen pressure detection is performed, and various useful signals such as transmission of this pen pressure data together with a control signal can be transmitted. is there.

When the switch 43A or the switch 43B of the pointing device 4 is turned on, light emission is started, and the light emission signal is a header consisting of a reader unit composed of a relatively long continuous pulse train and a code (a maker ID or the like) following the reader unit. The information is sequentially output according to a predetermined order and format of a transmission data string including a pen ID and a control signal (see FIG. 5, LSG signal).

In the embodiment of the present invention, in each data bit, the "1" bit is formed in a modulation format having an interval twice as long as the "0" bit. Various types can be used. However, as will be described later, it is desirable that the average amount of light is constant for coordinate detection, and that the clock component is sufficiently large for tuning the PLL. Considering that there is no problem even if the degree is relatively high, in the present embodiment, 6 bits (6 bits) are used.
4) data is 1 and 0 of a 10-bit length code.
Are the same and the number of consecutive 1s or 0s is 3 or less.
It is encoded by a method of assigning it to eight codes. By employing such an encoding method, the average power becomes constant and a sufficient clock component is included, so that a stable synchronization signal can be easily generated at the time of demodulation.

As described above, the pen down and pen button control signals are 2 bits, but must also transmit other long data such as ID. Therefore,
In this embodiment, the first two bits are a control signal, the next two bits are a content identification code (for example, the pen pressure signal is 00, the ID is 11, etc.), and the next two bits are these bits. Parity, and subsequently, 16-bit data and 2-bit parity are arranged to form one block of data. When such data is encoded by the method described above, a signal having a length of 40 bits is obtained.
A 10-bit sync code is added to the head of the code. This sync code is distinguished from a data word by using a special code of 4 0s, 5 consecutive 1s, or an inverted pattern thereof (switching depending on whether the end of the previous block is 1 or 0). It is easy to identify the position even in the middle of the data string and restore the data. Therefore, one block becomes a transmission signal having a length of 50 bits, which means that the control signal and data such as a 16-bit ID or writing pressure are transmitted.

In this embodiment, the first frequency is 60 kHz.
The second frequency is 7.5 kHz, which is 1/8 of the above.
Since the above-described coding method is employed, the average transmission bit rate is 2/3 of 5 kHz. Furthermore, since one block is 50 bits, 100 Hz is 1 bit.
This means that 24-bit data is transmitted in the block. Therefore, the effective bit rate excluding parity is 2
000 bits / sec. Although the redundancy is high,
This method can prevent erroneous detection and facilitate synchronization with a very simple configuration. In addition, by using a phase synchronization signal for sensor control described later and a check for a repetition period of a sync code, even if a short dropout occurs in the signal, the signal can be followed. The discrimination from the case where a quick operation such as double tap is performed can be surely performed by the presence or absence of the header signal. <Detailed Description of Coordinate Detector 1> FIG. 4 is a diagram showing a detailed configuration of the coordinate detector of the present embodiment.

The coordinate detector 1 includes a light receiving element 6 for detecting the amount of light with high sensitivity by a condensing optical system, and two linear sensors 20 for detecting an arrival direction of light by an imaging optical system.
X, 20Y. Then, the light beam from the light emitting element 41 incorporated in the pointing device 4 receives the diffused light from the light spot 5 generated on the screen 10. <Explanation of Operation of Light-Condensing Optical System> The light-receiving element 6 is provided with a light-condensing lens 6A as a light-condensing optical system, and detects a light amount of a predetermined wavelength with high sensitivity from the entire range on the screen 10. This detection output is detected by the frequency detection unit 71, and then demodulated by the control signal detection unit 72 into a digital signal including data such as a control signal (a signal superimposed by the light emission control unit 42 of the indicator 4).

A timing chart in the operation of restoring the control signal will be described with reference to FIG.

FIG. 5 is a timing chart in the control signal restoring operation of the present embodiment.

The data signal composed of the bit string as described above is detected by the light receiving element 6 as a light output signal LSG.
The frequency is detected by the frequency detector 71. The frequency detection unit 71
The optical output signal LSG is configured to be tuned to the pulse period of the highest first frequency in the optical output signal LSG. When used in combination with an optical filter, it is not affected by disturbance light.
The modulation signal CMD is demodulated. This detection method is similar to a widely used infrared remote controller, and is a highly reliable wireless communication method.

In this embodiment, the first frequency is set to 60 KHz, which is higher than that of a generally used infrared remote controller, so that no malfunction occurs even when used at the same time. The first frequency can be set to the same band as a generally used infrared remote controller. In such a case, malfunction is prevented by identifying the first frequency with an ID or the like.

The modulated signal CMD detected by the frequency detection unit 71 is interpreted as digital data by the control signal detection unit 72, and the above-described control signals such as pen-down and pen buttons are restored. The restored control signal is sent to the communication control unit 33. The modulation signal C
The code modulation cycle, which is the second frequency included in the MD, is detected by the sensor control unit 31, and this signal controls the linear sensors 20X and 20Y. That is, the sensor control section 31 resets at the timing of the header section (HEADER) shown in FIG. 5, and thereafter generates a signal LCK synchronized in phase with the falling edge of the modulation signal CMD.

Therefore, the generated signal LCK is a signal of a constant frequency synchronized with the presence or absence of light emission of the indicator 4. Further, from the modulation signal CMD, a signal LON indicating presence / absence of light input and a sensor reset signal RCL activated by the signal LON are generated. While the sensor reset signal RCL is at the high level, the two linear sensors 20X and 20Y are reset, and a synchronous integration operation described later is started at the falling timing of the sensor reset signal RCL synchronized with the rising of the signal LCK.

On the other hand, the control signal detecting section 72 detects the header section, and confirms that the input from the pointing device 4 has been started instead of other devices or noises. Is transmitted to the sensor control unit 31, the signal CON indicating the validity of the operation of the linear sensors 20X and 20Y is set to a high level, and the operation of the coordinate calculation unit 32 is started.

FIG. 6 shows a timing chart at the end of the series of operations when the light output signal LSG is lost. When the modulation signal CMD detected from the optical output signal LSG keeps the low level for a certain period of time or more, the signal LON indicating the presence or absence of the optical input goes low, and the signal CON indicating the validity of the sensor operation also goes low. As a result, the output operation of the coordinates by the linear sensors 20X and 20Y ends. <Description of Operation of Imaging Optical System> FIG. 7 shows a linear sensor 20X,
It is a figure which shows arrangement | positioning relationship of 20Y.

Referring to FIG. 7, for the sake of simplicity, an embodiment of the basic arrangement of the linear sensors 201X and 20Y will be described first. FIG. 7 shows an arrangement relationship between the two linear sensors 20X and 20Y, and an image of the light spot 5 is formed by the cylindrical lenses 90X and 90Y as the imaging optical system. Images 91X and 91Y are linearly formed on 21Y. By arranging these linear sensors 20X and 20Y accurately at right angles, an output having a peak at a pixel reflecting the X coordinate and the Y coordinate is obtained.

The linear sensors 20X, 20
Y is controlled by the sensor control unit 31, and an output signal is sent to the coordinate calculation unit 32 as a digital signal by an AD conversion unit 31 </ b> A connected to the sensor control unit 31. The coordinate calculation unit 32 calculates an output coordinate value from the input digital signal, and outputs the calculation result together with data such as a control signal from the control signal detection unit 72 via the communication control unit 33 to an external device using a predetermined communication method. It is sent to a control device (not shown). In addition, when performing an unusual operation (for example, setting a user calibration value) such as at the time of adjustment, a mode switching signal is transmitted from the communication control unit 33 to the sensor control unit 31 and the coordinate calculation unit 32.

In the present embodiment, defocusing is intentionally performed using a focus adjustment or a diffusion film so that the image of the light spot 5 has an image width several times as large as the pixels of the linear sensors 20X and 20Y. I have. According to experiments using a 1.5 mm diameter plastic cylindrical lens, a pixel pitch of about 15 μm, a linear CCD of 64 effective pixels, and an infrared LED, the sharpest image can be obtained over an entire angle of view of about 40 degrees. The image width becomes 15 μm or less. In such a state, it has been found that the result of the inter-pixel division calculation is distorted stepwise.

When the position of the lens was adjusted so that the image width was about 30 to 60 μm, very smooth coordinate data was obtained. Of course, if the image is largely blurred, the peak level will be reduced. Therefore, an image width of about several pixels is optimal. The use of a CCD with a small number of pixels and a moderately blurred optical system is one of the points of the present invention. By using such a combination, the amount of operation data is small, and a small sensor and optical system are required. In addition, a high-resolution, high-accuracy, high-speed and low-cost coordinate input device can be realized.

The X-coordinate detecting linear sensor 20X and the Y-coordinate detecting linear sensor 20Y arranged in an array have the same configuration. The detailed configuration will be described with reference to FIG.

FIG. 8 is a diagram showing a detailed configuration of the linear sensor of this embodiment.

The sensor array 21 serving as a light receiving portion is composed of N pixels (for example, a sensor array in which 64 photoelectric conversion elements are linearly arranged, and is defined as 64 pixels in this case). The charge according to the amount is stored in the integration unit 22. The N integrating units 22 can be reset by applying a voltage to the gate ICG, so that the electronic shutter operation can be performed. The electric charge stored in the integration unit 22 is transferred to the storage unit 23 by applying a pulse voltage to the electrode ST. The storage unit 23 includes 2N IRCLKs synchronized with the light emission timing of the indicator 4.
Electric charges are separately stored corresponding to the H (high level) and L (low level) of the signal. Thereafter, the charges separately accumulated in synchronization with the blinking of the light are transferred to the 2N linear CCD units 25 via the 2N shift units 24 provided for simplifying the transfer clock. Is done.

Thus, the linear CCD section 25 has N
The electric charges corresponding to the blinking of the light output from the sensor output of the pixel are stored adjacent to each other. These linear CCDs
The charges arranged in the part 25 are 2N ring CCs.
The data is sequentially transferred to the D unit 26. This ring CCD 26
After being emptied by the CLR unit 27 by the CLR signal, the charges from the linear CCD unit 25 are sequentially accumulated.

The charges thus accumulated are read out by the amplifier 29. The amplifier 29 is non-destructive and outputs a voltage proportional to the accumulated charge amount. In practice, the difference between the adjacent charge amounts, that is, the light emitting element 4
A value obtained by subtracting the charge amount at the time of non-lighting from the charge amount at the time of lighting 1 is amplified and output.

At this time, the obtained linear sensors 20X, 2
An example of the 0Y output waveform will be described with reference to FIG. 9 (the horizontal axis is the CCD pixel number, and the vertical axis is the output level).

In FIG. 9, the waveform B is a waveform when only the signal when the light emitting element 41 is turned on is read out, and the waveform A is a waveform when the light emitting element 41 is not turned on, that is, only the disturbance light (see FIG. 9). As shown in FIG. 8, the charges of the pixels corresponding to the waveforms of A and B are arranged adjacent to each other on the ring CCD section 26). The amplifier 29 non-destructively amplifies and outputs the difference value (the waveform of B-A) between the adjacent charge amounts. As a result, it is possible to obtain a signal of only the light from the indicator 4. It is possible to input coordinates stably without being affected by disturbance light (noise).

If the maximum value of the waveform B-A shown in FIG. 9 is defined as the PEAK value, the linear sensor 2
If the accumulation time during which each of the linear sensors 0X and 20Y functions is increased, the PEAK value increases in accordance with the time.
In other words, if the time corresponding to one cycle of the IRCLK signal is defined as a unit accumulation time and the number of accumulations n is defined using the unit as the unit, the PEAK value increases by increasing the number of accumulations n. Then, by detecting that the PEAK value has reached the predetermined magnitude TH1, it is possible to always obtain an output waveform of a constant quality.

On the other hand, when the disturbance light is very strong, the ring CC may reach the peak before the peak of the differential waveform BA becomes sufficiently large.
There is a possibility that the transfer charge of the D section 26 is saturated. In consideration of such a case, the SKIM unit 28 having a skim function is provided in each of the linear sensors 20X and 20Y.
Is attached. The SKIM unit 28 monitors the level of the non-lighting signal, and in FIG. 10, when the signal level exceeds a predetermined value at the n-th An (in FIG. 10, a dashed line).
A certain amount of charge is extracted from each of the pixels A and B. As a result, in the next (n + 1) -th time, a waveform as shown in An + 1 is obtained, and by repeating this, even if there is extremely strong disturbance light, signal charges can be accumulated without being saturated.

Therefore, even if the amount of blinking light from the pointing device 4 is weak, by continuing the integration operation many times, a sufficiently large signal waveform can be obtained.
In particular, when a light source in the visible light range is used for the indicator 4, the display image signal is superimposed. Therefore, by using the above-described skim function and difference output, it is possible to obtain a sharp waveform with very little noise. Becomes

When extremely strong disturbance light is incident, the PEAK value may be monitored, and the accumulation operation may be stopped when the PEAK value reaches a predetermined level. That is,
In such a case, a sufficiently high quality output waveform can be obtained without increasing the number of accumulations, so that highly reliable coordinate calculation can be performed. At the same time, since the number of times of accumulation is relatively small, the coordinate sampling rate per unit time is improved as compared with the case where the incident light is weak (for example, the coordinate calculation at 20 points / sec is 40 points / second). (Meaning that the coordinate calculation can be performed at a speed as high as a second).

Next, the operation control of the linear sensors 20X and 20Y will be described with reference to FIG.

FIG. 11 is a flowchart showing the operation control of the linear sensor according to this embodiment.

When the sensor control section 31 starts the sensor control operation, the signal CON is monitored in step S102. When the signal CON is at the high level (YES in step S102), the process proceeds to step S103.
The flag pon is set to 1 and the number of accumulations n is reset to 0. Then, in step S104, it is determined whether the PEAK value (peak level) of the sensor output is greater than a predetermined value TH1.

If the PEAK value is less than the predetermined value TH1 (NO in step S104), it is determined in step S105 whether the number of accumulations n is greater than a first predetermined number n0. If the number of accumulations n is less than the first predetermined number of times n0 (NO in step S105), the process proceeds to step S106, where the number of accumulations n is incremented by one, and step S1 is performed.
Return to 04. On the other hand, when the PEAK value is larger than the predetermined value TH1 (YES in step S104), or when the accumulation number n is larger than the first predetermined number n0 (step S1).
(YES in 05), the process proceeds to step S107, where the integration stop signal RON becomes high level (HI), and the integration operation is stopped. Then, the coordinate value calculation process by the coordinate calculation unit 32 is started.

Thereafter, in step S108, it is determined whether or not the number of accumulations n is greater than a second predetermined number of times n1. When the number of accumulations n is less than the first predetermined number of times n1 (NO in step S108), the process proceeds to step S109, the number of accumulations n is incremented by 1, and the process returns to step S108. On the other hand, when the accumulation number n is larger than the second predetermined number n1 (YES in step S108), step S110 is performed.
, The integration stop signal RON goes low, and at the same time, the sensor reset signal RCL goes high for several times (two times in FIG. 6) the period of the signal LCK. Next, in step S112, the signal CON is monitored. When the signal CON is at a high level (Y in step S112)
ES), and proceed to step S103. On the other hand, if the signal CON is at the low level (NO in step S112), the process proceeds to step S111 and waits for one processing cycle.

That is, while the signal CON is at the high level, this operation is repeated, and the coordinate value calculation is performed at intervals determined by the predetermined number n1. Also, under the influence of garbage,
Step S111 is provided so that the state is maintained only once even if the signal CON drops. if,
If the signal CON is at the low level for two consecutive periods (NO in step S102), the process proceeds to step S113, where the flag pon is reset to 0, a state waiting for a sync signal is returned, and the state returns to the initial state.

This dropout countermeasure portion can be longer than one cycle, and may be shortened if the disturbance is small. Note that the same operation can be performed by setting one cycle here as a natural number multiple of the above-described data block cycle and matching the sync code timing, and using a sync code detection signal instead of the signal CON.

The light of the indicator 4 reaching the coordinate detector varies due to the consumption of the power supply (battery) 44 built in the indicator 4 and also varies depending on the attitude of the indicator 4. In particular, when the light diffusing property of the screen 10 is small, the front luminance of the displayed image is improved, but the fluctuation of the amount of light input to the linear sensors 20 </ b> X and 20 </ b> Y due to the posture of the pointing tool 4 increases. However, according to the present invention, even in such a case, the number of integrations automatically follows and an always stable output signal can be obtained, so that stable coordinate detection can be performed. Also, when light is incident on the linear sensors 20X and 20Y without being scattered much as a pointer, considerably intense light enters, but it is clear that stable coordinates can be detected even in such a case. .

Further, the LE used by directly touching the screen is used.
When a pen using D and a pointer are used together, LEDs having a larger light amount can be used. Therefore, the first predetermined number n0 and the second predetermined number n which are the integration times shown in FIG.
Switching is performed by determining whether 1 is a pen or a pointer based on an ID signal, and it is also possible to set a high coordinate sampling rate for a pen and a low coordinate sampling rate for a pointer. Actually, a delicate drawing operation like character input cannot be performed with a pointer. Rather, it is more convenient to draw a smooth line at a low coordinate sampling rate, and it is effective to provide such switching.

As described above, the high-frequency carrier is added to the blinking light, and the timing of the integration operation is controlled by the demodulated signal of a predetermined period obtained by frequency-detecting the carrier. The image unit and the image unit can be synchronized cordlessly, and an easy-to-use coordinate input device can be realized. Further, by using a laser beam, it is possible to easily perform the operation at a position away from the screen. Further, since the integration control means for detecting that the peak level in the difference signal from the integration section exceeds a predetermined level and stopping the integration operation is provided, the signal of the light spot image having a substantially constant level even when the light amount changes. Can be created, whereby a stable and high-resolution coordinate calculation result can always be obtained. <Coordinate Value Calculation> The coordinate calculation process in the coordinate calculation unit 32 will be described.

The output signals (difference signals from the amplifier 29) of the two linear sensors 20X and 20Y obtained as described above are converted into digital signals by an AD conversion unit 31A provided in the sensor control unit 31, and the coordinate calculation unit 32,
Coordinate values are calculated. First, the coordinate values are calculated using the X coordinate,
For the output in each direction of the Y coordinate, the linear sensor 20X,
The coordinate value (X1, Y1) of 20Y is obtained. Since the calculation process is the same as the X coordinate and the Y coordinate, only the calculation of the X coordinate value will be described.

Next, a processing flow of the coordinate calculation processing of the present embodiment will be described with reference to FIG.

FIG. 12 is a flowchart showing a processing flow of the coordinate calculation processing of the present embodiment.

First, at the start of the process, a counter for counting the number of processes is set to cont = 0.

Next, in step S202, difference data Dx which is a difference signal of each pixel at an arbitrary coordinate input point is obtained.
(N) (for example, the number of pixels n = 64) is read. next,
In step S203, an average value of output values of each pixel (64 pixels) is derived, and Vth1 to which a predetermined offset amount Voff is added is defined. This Vth1 is used as a first threshold for determining the validity of the output signal (see FIG. 13A). In other words, Vth1 varies depending on the amount of light input to the linear sensor, that is, the signal level, and also depends on the output voltage when the above-mentioned amount of light is not incident at all. And the optimum threshold level can be automatically set.

Next, in step S204, a peak pixel n _peak having the maximum value of the difference data Dx (n) is detected. In step S205, the peak pixel n _peak
Output value of the m-th pixel before and after, Dx (n _peak −m), D
x (n _peak + m) is obtained, and the values are compared. Next, in steps S206 and S207, the second threshold value Vth2 is set to Dx (n _peak −m), Dx
(N _peak + m). In this embodiment, the signal levels are smaller value to a threshold level, the state of the case of the m = 3 shown in FIG. 13 (b), the threshold is set to Dx (n _{pe ak} -m) It is understood that. In the case of this embodiment, at both signal levels,
Although the smaller value is adopted as the threshold level,
The same effect can be obtained by increasing the value of m and adopting a higher signal level as the threshold level.

Next, in step S208, the first threshold value Vth1 is compared with the second threshold value Vth2. Second threshold V
When th2 is equal to or greater than the first threshold value Vth1 (step S20)
(YES at 8), assuming that valid light has sufficiently entered, and executes coordinate calculation from step S209. On the other hand, when the second threshold value Vth2 is less than the first threshold value Vth1 (NO in step S208), the process is stopped because sufficient light is not obtained.

In step S209, the second threshold V
E which is a difference between th2 and difference data Dx (n) of each pixel.
x (n) is stored in the nonvolatile memory 9. Next, in step S210, an effective pixel for coordinate calculation is determined. The output value of this effective pixel is the second threshold value Vth2
And that the continuous pixels including the peak pixels n _peak exceeding, the minimum value n _min of the previous output value of the pixel group of pixels that exceeds the second threshold value Vth2 continuously peak pixel n _peak, peak pixel n the output value of the pixel group after the _peak is continuous to the maximum value n _max of the pixels exceeds a second threshold value Vth2 is effective pixels. As an example, in FIG. 13C, the minimum value n _min is n
the difference data _peak -m is Dx (n _{p eak} -m), the difference data by the maximum value n _max is n _peak + m + 1 becomes _{Dx (n peak + m + 1} ). In this case, the output value of the pixel of n _peak + m is greater than n _peak + m + 1 is also used as valid data when the coordinate calculation. FIG.
In 3 (c), there are other pixels exceeding the second threshold value Vth2, but they do not satisfy the continuity condition, and thus are not effective pixels.

Using the output value of the effective pixel, step S2
At 11, pixel coordinates X1 on the linear sensor 20X are calculated. In the present embodiment, the center of gravity of the output data is calculated by the center of gravity method. However, the mathematical method for obtaining the pixel coordinates X1 includes, for example, a method for obtaining the peak value of the output data Ex (n) (for example, by a differentiation method), and is not limited to the calculation method.

Next, a method for obtaining the position coordinates of the pointing tool 4 from the derived pixel coordinates X1 will be described. Here, in order to calculate the coordinates from the pixel coordinates X1 of the output data, it is necessary to calculate a predetermined value for setting the reference point at the time of the initial operation.
It is determined whether it is a routine for calculating the predetermined value (reference point setting mode) or a mode for calculating a normal coordinate value based on the predetermined value (coordinate calculation mode).

The reference point setting mode is normally performed at the time of shipment from the factory, and is executed based on an instruction from a predetermined switch or the indicator 4 provided in the main body of the coordinate input device.

In step S212, the reference point setting mode
If it is a mode, at least two
Coordinates of known points (αcont, βcont) and their centroids
X1 _contIs calculated. Specifically, first, step S2
13, the screen when the counter cont = 0
Indicates the coordinate value (α0, β0) of the first known point on 10
Then, the processing in steps S202 to S212 described above is performed.
By executing the processing, the coordinate value and the center of gravity value X1₀Calculate
Then, the obtained result is stored in the nonvolatile memory 9.

Next, in step S214, the counter cont is incremented by one. Then, in step S215, the counter value of the counter cont is 1
It is determined whether it is greater than. If it is not greater than 1 (NO in step S215), the process proceeds to step S202, in which the coordinates of the second known point (α1, β1) are specified, and the above-described processes of steps S202 to S212 are executed. Accordingly, in step S213, to calculate the coordinate values and the centroid value X1 _1, the results obtained are stored in the nonvolatile memory 9. Then, in step S214,
The counter cont is incremented by one, and the counter value becomes one. Thus, in step S215, the counter value of the counter cont becomes larger than 1, and the process ends.

By the above processing, the coordinate values (α
0, β0) and (α1, β1), and their centroid values X1 ₀ , X1
₁ is stored in the nonvolatile memory 9 as a reference point.

On the other hand, if it is determined in step S212 that the current mode is not the reference point setting mode, that is, if it is in the ordinary coordinate calculation mode, the coordinates of the calculation target are calculated in step S216 using the coordinate values of the reference points stored in the nonvolatile memory 9. The X coordinate of the coordinate input point is calculated. Step S217
In order to provide a higher-performance coordinate input device, coordinate values are corrected as necessary (for example, distortion is corrected by a software operation to correct lens aberration of an optical system). To determine the coordinate values.

The determined coordinate values can be output as they are in real time, or data can be thinned out according to the purpose (for example, only one data is output for every ten determined coordinates). Needless to say, it is important when assuming the following specifications.

The stability of the user's hand differs between the case where the pointing tool 4 is used like a pen and the case where the pointing tool 4 is used away from the screen as a pointer. When used as a pointer, the cursor on the screen will tremble finely, so it is easier to use such a fine movement. On the other hand, when used like a pen, it is required to follow as quickly as possible. In particular, when writing a character, if a small quick operation cannot be performed, the input cannot be performed correctly.

In the present embodiment, since the ID is transmitted by the control signal, it is possible to determine whether or not the pointer is of the pointer type based on whether or not the switch at the tip is pressed. You can determine whether you are using. If it is a pointer, for example,
The coordinate values (X-1, Y-1) and (X-
By calculating the moving average using (2, Y-2) and calculating the current output coordinate values (X, Y), a configuration with less blur and good operability is obtained.

In the present embodiment, a simple moving average is used for coordinate calculation when the pointer is used as a pointer. However, as a function used for smoothing processing for calculating such a moving average, other functions are used. Various methods can be used, such as non-linear compression of the absolute value of the difference according to the magnitude, and non-linear compression of the difference from the predicted value based on the moving average using the predicted value. In other words, the control signal can switch the level of smoothing to a higher level when the pointer is used as a pointer and to switch to a lower level when the pointer is used as a pen. Therefore, it is possible to realize convenient states, and the effect of the present invention is great also in this respect.

Note that these coordinate calculation processes are performed when the coordinate sampling rate is 100 Hz, as described above.
The processing may be completed within 0 msec, and the data is 64 pixels ×
Since it is very small, that is, 8 bits of 2 (X and Y) × AD conversion circuits, and no convergence operation is required, a low-speed 8-bit one-chip microprocessor can sufficiently perform processing. This is advantageous not only in terms of cost, but also in that specifications can be easily changed, development time can be shortened, and various derivative products can be easily launched. In particular, there is no need to develop a dedicated LSI for performing high-speed image data processing as in the case of using an area sensor, and the advantages such as development cost and development period are very large.

The data signal indicating the coordinate value (X, Y) calculated by the coordinate calculation processing as described above is sent from the coordinate calculation unit 32 to the communication control unit 33. This communication control unit 3
3, the data signal and the control signal from the control signal detection unit 72 are input. The data signal and the control signal are both converted into a communication signal of a predetermined format and sent to an external display control device. Thus, various operations such as input of a cursor, a menu, characters and line drawings on the screen 10 can be performed. As described above, even when a linear sensor composed of 64 pixels of photoelectric conversion elements is used, a resolution of more than 1000 and sufficient accuracy can be obtained, and both the linear sensor and the optical system can be small in size and low in cost. Thus, it is possible to obtain a coordinate input device that can also have a very small configuration in the arithmetic circuit.

When the sensor is configured as an area sensor and the resolution is doubled, a quadruple number of pixels and calculation data are required. On the other hand, when the sensor is configured as a linear sensor. , X coordinate and Y coordinate need only be doubled. Therefore, it is easy to increase the number of pixels to achieve higher resolution.

As described above, according to the present embodiment, the difference signal is calculated by separately integrating the signals at the time of lighting and the time of non-lighting of the light spot blinking at a predetermined cycle by the pointing tool 4. Since the position of the peak pixel is determined with high accuracy, high-precision, high-resolution coordinate values can be obtained.
Further, the influence of disturbance light can be suppressed, and a small, lightweight, low-cost coordinate input device can be realized.

Now, the enlargement and high definition of the display device 8 have been remarkable recently.
2. Description of the Related Art Large-size display devices such as inch-size display devices are becoming widespread, and it is necessary to consider further increase in size. As a coordinate input device corresponding thereto, the coordinate input device as in the present embodiment can cope with the expansion of the coordinate input effective area by appropriately setting the optical system, particularly the optical path length, The absolute accuracy of the coordinate input device,
The resolution will be reduced. For example, in the case of a coordinate input effective area with a diagonal of 50 inches, the coordinate calculation resolution is 1 mm.
If it is assumed that only a change in the optical path length corresponds to a diagonal of 70 inches, the coordinate calculation resolution is reduced to about 1.4 mm. Therefore, it is important to realize a higher-resolution coordinate input device in view of an increase in the size of the device.

However, with such a configuration, in order to ensure higher-resolution coordinate calculation performance, it is necessary to perform coordinate calculation using more output information from the linear sensors. For example, A) the image forming optical system is defocused and the light spot 5
From the light source can be incident on more linear sensors.

B) The number of photoelectric conversion elements constituting the linear sensor is increased. However, each of the methods has the following adverse effects.

In the method A), since the light from the light spot 5 is blurred, it is apparent that the signal level output from each pixel on the linear sensor is reduced as a whole. Further, since the signal level used in calculating the coordinates becomes smaller as a whole, the number of a series of effective pixels including the peak pixel on the linear sensor increases, so that the S / N ratio of the signal of the linear sensor is reduced. Need to be considered enough.

Therefore, in order to obtain the reliability of the output signal, the amount of light emission per unit time of the light emitting element 41 incorporated in the indicator 4 must be increased or the light from the indicator 4 must be It is necessary to make the integration time, which is the time for taking in, longer.

The method of increasing the amount of light emitted by the light emitting element 41 of the pointing device 4 per unit time has, of course, limitations due to the restrictions imposed by the light emitting element 41 and also results in an increase in power consumption. As a result, the power supply unit 44 incorporated in the pointing device 4 is greatly consumed, the running cost is increased, or a charging method is indispensable. Causes major obstacles.

The method of making the integration time, which is the time for taking in the light from the pointing device 4 longer, causes a decrease in the coordinate calculation sampling rate. That is, for example, 20
If a sufficiently reliable output signal can be obtained with an integration time of about msec, 1
Although 50 coordinate outputs per second are possible, the integration time is 40 msec in order to defocus more and realize a reliable output signal in order to achieve higher resolution.
Then, the coordinate output sampling rate is 25 times /
Secondly, there is an adverse effect that performance is extremely deteriorated.

On the other hand, in the method B), for example, depending on whether the distance of 1 meter is measured by 64 photoelectric conversion elements (64 pixels) or 128 (128 pixels), It is self-evident that the latter has higher resolution. However, such a configuration increases the number of drive circuits for driving the number of photoelectric conversion elements by the number of the circuits, and increases the cost. Further, in order to prevent the coordinate calculation sampling rate from lowering, higher-speed processing is required, and a significant increase in cost is inevitable.

Therefore, in order to solve such a problem, the present invention constitutes a coordinate input device having an imaging optical system as shown in FIG. Although FIG. 14 describes only the X-axis direction, the Y-axis direction has the same configuration.

FIG. 14 is a diagram showing a configuration example of an image forming optical system according to the present embodiment.

The configuration shown in FIG. 14 is for increasing the number of photoelectric conversion elements in the X-axis and Y-axis directions as compared with the imaging optical system described above with reference to FIG. That is, as shown in the drawing, two linear sensors 20X are used, each of which has a photosensitive unit 21XL, 21XR.
20XL and respective linear sensors 20XR, 20X
The cylindrical lenses 90XR and 90XL corresponding to L are configured. As a result, the number of pixels in the X-axis direction is doubled, that is, the coordinate calculation resolution is doubled, and it can be expected that the coordinate calculation accuracy and the resolution are significantly improved.

FIG. 15 is a view of the image forming optical system of FIG. 14 viewed from the upper side. When the pointing tool 4 is located on the right side of the screen 10 which is a coordinate input surface, the light spot 5 is Light is incident, and when the indicator 4 is on the left side of the screen 10, the light of the light spot 5 is incident on the linear sensor 20XL.

Therefore, the light from the pointing device 4 is incident on at least one of the linear sensors 20XR and 20XL. When the indicator 4 is located near the center, light may be incident on both the linear sensors 20XR and 20XL, and which of the linear sensors will be used to calculate the coordinates will be described later.

However, this linear sensor 20X
If a drive circuit for driving R and 20XL is provided, the cost doubles. If one drive circuit is used, the linear sensors 20XR and 20XL operate in a time-division manner (for example, alternately). Operation). In that case, to obtain a signal for which coordinates can be calculated, for example, 20 ms
If ec is required, alternate driving takes 40 msec, and the coordinate sampling rate is reduced by half. Therefore, the present invention suppresses the cost increase and does not lower the coordinate sampling rate as much as possible.
A high-precision, high-resolution coordinate input device is realized.

FIG. 1 shows an operation for realizing this.
6, a specific description will be given with reference to FIG.

FIG. 16 is a flowchart showing a processing flow of the coordinate calculation processing of this embodiment.

Since the calculation process is the same as the X coordinate and the Y coordinate, only the calculation of the X coordinate value will be described.

First, in step S302, a counter G_no = 0 for selecting one of the two linear sensors in the same direction is reset. For example, when the counter G_no = 1, the linear sensor 20XR is selected,
Assume that the counter G_no = 2 is designed to select 20XL.

Next, in step S303, the counter value of the counter G_no is incremented by one. next,
In step S304, it is determined whether the counter value of the counter G_no exceeds a maximum value Nmax (in the present embodiment, the maximum value Nmax = 2). If it exceeds the maximum value Nmax (YES in step S304), the process ends. On the other hand, if it does not exceed the maximum value Nmax (NO in step S304), the process proceeds to step S305.

In step S305, the counter G_n
Select the linear sensor corresponding to the counter value of o. Next, in step S306, the linear sensor is operated for a first predetermined time, and the light emitted from the indicator 4 is detected. This first predetermined time is set to a value sufficiently smaller than the time required to acquire an output signal enabling coordinate calculation from the linear sensor. This first
FIG. 17A shows an example of an output signal from the linear sensor when the linear sensor is driven for a predetermined time. The output signal is compared at a predetermined threshold level V to distinguish it from the noise level. If there is an output signal at or above the threshold level V, it is assumed that the light from the indicator 4 has been detected by the linear sensor.

Therefore, in step S307, based on the result of the comparison, it is determined whether or not the light emitted from the pointing device 4 is detected by the linear sensor. If no light is detected (NO in step S307), step S3
Return to 03. On the other hand, when light is detected (step S30)
(YES at 7), the process proceeds to step S308.

In step S308, the linear sensor is further driven for a second predetermined time, and an output signal enabling coordinate calculation is obtained from the linear sensor. FIG. 17B shows an example of an output signal from the linear sensor when the linear sensor is driven for the second predetermined time.

On the other hand, if it is determined in step S307 that the linear sensor has failed to detect the light from the pointing device 4, the process returns to step S303, where the counter G_no is incremented by 1, and another linear sensor is selected in step S305. Execute the processing of

In the above processing, when light from the pointing device 4 cannot be detected by any of the linear sensors, that is, when the counter G_no exceeds Nmax in step S304, a coordinate input operation by the pointing device 4 is being performed. If not, the process ends.

In the above processing, the counter G_no =
1, that is, the linear sensor 20XR can detect light from the pointing tool 4 and output an output signal capable of calculating coordinates to the linear sensor 2XR.
Time for acquiring from 0XR is 20 msec (for example, first predetermined time 5 msec, second predetermined time 15 msec)
In the case of (sec), the coordinates can be calculated at that time.

On the other hand, when coordinates are not calculated by the first linear sensor 20XL, the second linear sensor 20XL
In this case, the first linear sensor 20XR has a first predetermined time of 5 msec, and the second linear sensor 20XL has a first predetermined time of 5 msec. The predetermined time takes 15 msec, and the processing time for the two linear sensors is 25 msec in total, and the coordinate calculation processing of the present embodiment can be completed in 25 msec. That is, it is possible to prevent a significant decrease in the coordinate calculation sampling rate as compared with the conventional example in which the coordinate calculation processing is completed in 40 msec.

The image forming optical system may have a configuration as shown in FIG.

FIG. 18 is a diagram showing another example of the configuration of the imaging optical system of the present embodiment.

The image forming optical system shown in FIG.
This is a configuration in the case where the number of photoelectric conversion elements constituting the linear sensor is greatly increased. However, driving all the photoelectric change elements at the same time leads to a significant cost increase as described above. Therefore, in the present embodiment, each photoelectric conversion element is divided into a plurality of groups, and the groups are configured to operate independently in units of the groups.

Referring to FIG. 18, when the first area, which is the center of the screen 10, is pointed by the pointing tool 4, the group of photoelectric conversion elements that receive light from the pointing tool 4 is changed to the first group.
Similarly, when the area 4 and the second area and the third area, which are both peripheral portions of the screen 10, are designated by the indicator 4, the group of the photoelectric conversion elements that receive the light from the indicator 4 is referred to as the area light receiving group. Two areas and a third area light receiving group. Further, in the vicinity of the boundary between the first to third regions on the screen 10, light is incident on the plurality of light receiving groups, and corresponds to the plurality of regions on which the light from the pointing tool 4 is incident. It is configured to calculate coordinates using an optical output signal from a photoelectric conversion element of one of the light receiving groups.

The coordinate calculation process is performed in the same manner as in FIG.
Can be performed. That is, by applying FIG. 16 to each of the first to third area light receiving groups, the same coordinate calculation processing can be executed. In this case, Nmax = 3. In the case of the configuration of the imaging optical system in FIG. 18, the processing time for the three first to third area light receiving groups is 30 msec, and the coordinate calculation processing can be completed in 30 msec. Also in this case, it is possible to prevent a significant reduction in the coordinate calculation sampling rate as compared with the conventional example.

With the above configuration, the cost can be reduced and the coordinate calculation sampling rate can be reduced.
The coordinates can be calculated with high accuracy and high resolution.
In addition to this, the coordinate calculation sampling rate can be further improved. The coordinate calculation process in this case will be described with reference to FIG.

FIG. 19 is a flowchart showing a modification of the processing flow of the coordinate calculation processing according to the present embodiment.

FIG. 19 is a modification of the flowchart of FIG. 16 in which the order of selecting a plurality of linear sensors as shown in FIG. 14 or a plurality of light receiving groups as shown in FIG. 18 is devised.

First, in step S402, it is determined whether the coordinate input device is outputting coordinate values continuously or intermittently / instantly. As described above, this type of coordinate input device can output coordinate values in units such as 20 points / second. Therefore, when coordinates are continuously input (such as when writing), coordinate values are always output within a predetermined time, and if the time is monitored, continuous It is possible to determine whether coordinates have been input or not.

If the coordinate values have not been output continuously (NO in step S402), in step S403
A function F for determining a linear sensor / light receiving group to be processed based on the counter value of the counter G_no is a function
Determined as Func.1. On the other hand, when the coordinate values are not continuously output (YES in step S402), step S4
Go to 04.

The function Func.1 is defined so as to select a linear sensor / light receiving group in order from a region having a high probability of inputting coordinates. For example, in FIG. 18, since it is considered that the instruction near the center of the display area, that is, near the center of the coordinate input effective area is considered to be the most frequent, the linear sensor / light receiving group that can first detect the light spot on that area , And sequentially define a linear sensor / light receiving group capable of detecting a light spot on a high-frequency area. Selected linear sensor /
If the coordinate value can be calculated in the light receiving group, it is possible to proceed to the next coordinate sampling operation, so that the stochastically highest coordinate sampling rate can be obtained.

On the other hand, if the coordinate values are continuously output, the coordinate value output immediately before is known, and in step S413, selection information (counter) indicating the linear sensor / light receiving group that output the coordinate values is output. G_no is stored in the nonvolatile memory 9. Therefore,
In step S404, the selection information is read.
Then, in step S405, a function F for determining a linear sensor / light receiving group to be processed is determined as a function Func.2 based on the counter G_no.

When the coordinate values are continuously output,
Since the coordinate value output at a certain point in time is very likely to be near the coordinate value output immediately before, the function Func.
Linear sensor with the previously output coordinate value as the detection range
The linear sensor / light receiving group is defined so as to select the light receiving group, and sequentially selects the linear sensor / light receiving group whose detection range is a region far from the coordinate value detected immediately before. With this configuration, it is possible to stochastically obtain the highest coordinate sampling rate.

In step S406, the counter G_n
Increment the counter value of o by one. Next, in step S407, it is determined whether the counter value of the counter G_no exceeds the maximum value Nmax. If it exceeds the maximum value Nmax (YES in step S407), the process ends. On the other hand, if it does not exceed the maximum value Nmax (NO in step S407), the process proceeds to step S408.

In step S408, the counter values are substituted into the functions Func.1 / Func.2 determined by the above processing, and the linear sensor / light receiving group indicated by the result is selected. Next, in step S409, the linear sensor / light receiving group is operated for a first predetermined time, and the light emitted from the indicator 4 is detected.

In step S410, the output signal is compared with the threshold level V to determine whether the linear sensor / light receiving group has detected light. If no light is detected (NO in step S410), the process returns to step S406. On the other hand, if light is detected (YE in step S410)
S), and proceed to step S411.

In step S411, the linear sensor / light receiving group is continuously driven for a second predetermined time.
An output signal enabling coordinate calculation is obtained from the linear sensor / light receiving group. Then, in step S413, the counter value of the counter G_no is stored as selection information in the nonvolatile memory 9, and the process ends.

An object of the present invention is to supply a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU or MPU) of the system or the apparatus. Can also be achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R / RW, DVD-ROM / RAM, magnetic tape, non-volatile memory card, ROM and the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts described above.

[0152]

As described above, according to the present invention,
A coordinate input device capable of outputting coordinates with high accuracy and high resolution at low cost without lowering the coordinate calculation sampling rate, a control method thereof, and a program can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a coordinate input device according to an embodiment.

FIG. 2 is a diagram showing a detailed configuration of a pointing device of the embodiment.

FIG. 3 is a diagram illustrating an operation mode of the pointing device according to the embodiment.

FIG. 4 is a diagram illustrating a detailed configuration of a coordinate detector according to the present embodiment.

FIG. 5 is a timing chart in a control signal restoring operation of the embodiment.

FIG. 6 is a timing chart of signals handled in the present embodiment.

FIG. 7 is a diagram showing an arrangement relationship of the linear sensor according to the embodiment.

FIG. 8 is a diagram showing a detailed configuration of the linear sensor of the present embodiment.

FIG. 9 is a diagram illustrating an example of an output waveform of the linear sensor according to the embodiment.

FIG. 10 is a diagram showing an example of an output waveform for explaining a skim operation of the linear sensor according to the embodiment.

FIG. 11 is a flowchart showing operation control of the linear sensor according to the embodiment.

FIG. 12 is a flowchart illustrating a processing flow of coordinate calculation processing according to the present embodiment.

FIG. 13 is an explanatory diagram related to coordinate calculation according to the present embodiment.

FIG. 14 is a diagram illustrating a configuration example of an imaging optical system according to the present embodiment.

FIG. 15 is a top view illustrating a configuration example of an imaging optical system according to the present embodiment.

FIG. 16 is a flowchart illustrating a processing flow of coordinate calculation processing according to the present embodiment.

FIG. 17 is a diagram illustrating an example of an output waveform of the linear sensor according to the embodiment.

FIG. 18 is a diagram illustrating another configuration example of the imaging optical system of the present embodiment.

FIG. 19 is a flowchart illustrating a modification of the processing flow of the coordinate calculation processing according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coordinate detector 2 Coordinate detection sensor part 3 Controller 4 Indicator 5 Light spot 6 Light receiving element 6a Condensing lens 7 Signal processing part 8 Projection display device 9 Non-volatile memory 81 Image signal processing part 82 Liquid crystal panel 83 Lamp 84 Mirror 85 Condenser Lens 86 Projection lens 20X, 20Y Linear sensor 21 Sensor array 22 Integrator 23 Shifter 24 Storage unit 25 Linear CCD 26 Ring CCD 27 Clear unit 28 Skim unit 29 Amplifier 31 Sensor control unit 31A AD conversion unit 32 Coordinate operation unit 33 Communication control Unit 71 Frequency detection unit 72 Control signal detection unit

Claims (13)

[Claims] 1. A coordinate input device for irradiating a coordinate input screen with light from a pointing tool to generate a light spot and generating coordinates corresponding to the light spot, comprising: a plurality of detection areas; Detecting means for detecting an optical signal from the light spot, wherein a detecting operation in the detecting area is independently controlled; and executing a detecting operation in a first detecting area among the plurality of detecting areas for a first predetermined time. A driving unit that determines whether or not there is an optical signal from the light spot based on a detection result from the first detection area obtained by the driving unit. If the determination is made, first control means for controlling the driving means so as to further execute the detection operation of the first detection area for a second predetermined time; and if the determination means determines that there is no optical signal, Other than the first detection area A second control for executing the driving means and the determination means for the detection area, and controlling the driving means so as to further execute a detection operation of the detection area determined to have the optical signal for a second predetermined time. Means for inputting coordinates, comprising: a coordinate calculation means for calculating a coordinate value corresponding to the light spot based on a detection result from a detection area determined to have the optical signal by the determination means. apparatus. 2. The apparatus according to claim 1, wherein the determination unit determines that there is an optical signal from the light spot when a detection result from the first detection area is equal to or more than a predetermined value. Coordinate input device. 3. The coordinate input device according to claim 1, wherein said detection means physically comprises a plurality of sensors, and said plurality of detection areas correspond to respective detection areas of said plurality of sensors. apparatus. 4. The apparatus according to claim 1, wherein said detection means comprises a single sensor, and said plurality of detection areas correspond to respective area groups obtained by dividing the detection area of said sensor into a plurality of groups. Coordinate input device as described. 5. The coordinate input device according to claim 1, wherein the first detection area corresponds to a central area on the coordinate input screen. 6. The coordinate input device according to claim 1, further comprising a selection unit that selects the first detection area based on an output interval of a calculation result of the coordinate calculation unit. 7. A control method for a coordinate input device that irradiates a coordinate input screen with light from a pointing tool to generate a light spot and generates coordinates corresponding to the light spot, wherein the light from the light spot is provided. A driving step of executing a detection operation in a first detection area for a first predetermined time among a plurality of detection areas in which detection operations for detecting signals are independently controlled; and the first detection area obtained by the driving step A determination step of determining the presence or absence of an optical signal from the light spot based on the detection result from the step (a). A first control step of controlling the driving step so as to execute for a predetermined time; and if the determining step determines that the optical signal is not present, the driving step and the driving step are performed for other detection areas other than the first detection area. The judgment And a second control step of controlling the driving step so as to further execute a detection operation of a detection region determined to have the optical signal for a second predetermined time; and A coordinate calculation step of calculating a coordinate value corresponding to the light spot based on a detection result from the detection area determined as above. 8. The method according to claim 7, wherein the determining step determines that there is an optical signal from the light spot when a detection result from the first detection area is equal to or more than a predetermined value. Control method of a coordinate input device. 9. The control method for a coordinate input device according to claim 7, wherein each of the plurality of detection areas physically corresponds to each detection area including a plurality of sensors. 10. The method according to claim 7, wherein the plurality of detection areas correspond to each area group obtained by dividing a detection area of one sensor into a plurality of groups. 11. The method according to claim 7, wherein the first detection area corresponds to a central area on the coordinate input screen. 12. The method according to claim 7, further comprising a selecting step of selecting the first detection area based on an output interval of a calculation result of the coordinate calculating step. . 13. A program that causes a computer to control a coordinate input device that generates a light spot by irradiating light from a pointing tool onto a coordinate input screen and generates coordinates corresponding to the light spot. A program code for a driving step of executing a detection operation in a first detection area for a first predetermined time among a plurality of detection areas in which detection operations for detecting an optical signal from a light spot are independently controlled; Based on the detection result from the first detection region obtained by the above, a program code of a determination step of determining the presence or absence of an optical signal from the light spot, and if the determination step determines that there is the optical signal, A program code of a first control step for controlling the driving step so as to further execute a detection operation of a first detection area for a second predetermined time; If it is determined that there is no light signal, the drive step and the determination step are performed on other detection areas than the first detection area, and the detection operation of the detection area determined to have the optical signal is further performed by a second predetermined A program code of a second control step of controlling the driving step so as to execute the time, and a coordinate corresponding to the light spot based on a detection result from a detection area determined to have the light signal in the determination step. A program code for a coordinate calculation step for calculating a value.