JP2000284908A - Device with integrated input and output - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently ensure the input light quantity of a pen from the screen of an optical coordinate input device. SOLUTION: A screen is constituted of a Fresnel plate constituted of Fresnel lenses for making image light beams from projecting lens in parallel with the optical axes and a lenticular plate 10-2 constituted of lenticular lenses 10-2-1 for performing diffusing action in the horizontal direction. Then, the lenticular lens 10-2-1 is provided with an optical characteristics region in which the pen input light can be made in parallel with the optical axis of the image projected light. Thus, the Fresnel effect can be increased, and converging characteristics can be more improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an integrated input / output device including a coordinate input device used in a large display system. More specifically, the present invention relates to an input / output integrated device including a coordinate input device used for controlling an externally connected computer or writing characters, graphics, and the like by inputting coordinates on a screen of a large display with a pointing tool. .

[0002]

2. Description of the Related Art A conventional coordinate input device captures a light spot from a light-emitting pen or the like on a screen using a CCD area sensor or a linear sensor, and performs image processing such as using barycentric coordinates or pattern matching. And those that calculate and output coordinate values and those that use a position detecting element called PSD (an analog device that can obtain 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 No. 2503182 discloses that PS
Regarding an apparatus using D, a configuration 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 use it in a brightly lit environment. Demand is expanding because an integrated device can be configured.

[0006] 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.

In recent years, the number of devices using infrared rays as wireless communication means has increased, and the amount of disturbance light has increased in both infrared and visible light. One of the characteristics.

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, the above-mentioned patent application No. 2503l
As in No. 82, in a device using a PSD, the light intensity is frequency-modulated, and the modulated wave is synchronously detected, so that the influence of disturbance light can be suppressed. Have strong characteristics.

[0010] In addition, the resolution of the large-screen display has been improved as well as the brightness. For this reason, it is necessary to improve the resolution of the coordinate input device, but there is a problem in this respect in a device using a PSD that is strong against disturbance light.

That is, since the dynamic range of the sensor output voltage directly corresponds to the input range, for example, when the whole is decomposed into coordinates of 1000, at least 6
Since an S / N ratio of 0 dB or more is required, and digital correction of a linearity error is indispensable, as described in the above-mentioned Japanese Patent No. 2503182, a high-precision analog circuit and a multi-bit AD converter are required. 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 the simultaneous use of a plurality of video cameras. 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, and it is very large and expensive for real-time operation. .

In Japanese Patent Application Laid-Open No. 6-274266, high resolution can be obtained by using a special optical mask and signal processing.
If the N ratio can be secured, high resolution can be achieved.

However, in actuality, the linear sensor forms an image in a linear manner, and cannot separate the light from disturbance light in a plane as compared with an area sensor that forms a point image. There is a problem that it is practical only in a special environment with little light.

When the coordinate input device is combined with a projection type large screen display, a screen used for the projection type large screen display is designed to secure a wide viewing angle on the front side which is an input side and a screen viewing side. It is a known technique to use a screen having a Fresnel lens and a lenticular lens surface, and to additionally use a diffusing material or the like.

However, if this screen is used in a device combining the coordinate input device and the projection type large screen display without simply considering the position of the sensor, the light of the light spot from a pointing tool such as a pen is There is a problem that the light is not collected and the light quantity is insufficient. Furthermore, for example,
As disclosed in 58-59436, a convex lenticular lens having a curvature in the horizontal direction is provided on both front and back sides, and in order to improve contrast, the lenticular lens is provided on the viewing side (image light output side) to improve contrast. There is known a screen configuration in which a flat black-like thin surface (black stripe) facing a valley on the back surface of a lenticular lens is formed together with a Fresnel plate.

However, when detecting the coordinates of a light spot from a pointing tool such as a pen on the screen screen, the light input to the sensor is blocked by the black stripe, and a sufficient amount of detected light cannot be secured. There is. In such a case, FIGS. 13A and 13B
As shown by, it is easily devised to use a wrench plate that does not form a black stripe on a plane facing the valley on the back surface of the lenticular lens.

However, in this case, with respect to the image light as shown in FIG. 13A, strong diffusion in the horizontal direction occurs with respect to a group of light rays (arrows →) parallel to the optical axis of the image light after passing through the Fresnel plate. Although there is an effect of improving the viewing angle, the light beam (arrow ←) from a pointing tool such as a pen is incident on any of the above-mentioned lens portion and the above-mentioned plane and is parallel to the optical axis to the Fresnel plate. There is a problem that the light is not a light beam but a diffused light, and a sufficient amount of detected light cannot be secured to the sensor.

It is an object of the present invention to provide a high-resolution and high-performance coordinate input device that secures a sufficient amount of incident light on a sensor while maintaining a wide viewing angle of a projected image.

[0022]

In order to solve the above-mentioned problems, the present invention provides an image pickup device for irradiating a predetermined position on a coordinate input screen with light from a pointing tool to generate a light spot and picking up the light spot. A coordinate input device comprising: means for generating a coordinate output signal corresponding to a predetermined position on the coordinate input screen of the spot from an output signal of the imaging means; and projecting an image on the coordinate input screen to form an image. An input / output integrated device comprising projection type display means for causing the image input means to be disposed substantially in the vicinity of a projection lens of the projection type display means, and displaying the coordinate input screen with image projection light on the image projection side. A Fresnel plate having a Fresnel lens parallel to the optical axis of the projection lens and condensing the light from the pointing tool to the imaging means, and a lenticular lens for diffusing image projection light on the coordinate input surface side. Be comprised of the wrench plate for providing input and output integrated device according to claim.

Preferably, in the present invention, the object-side focal point of the Fresnel lens substantially coincides with the exit position of the projection lens of the projection display unit and the sensor position of the imaging unit of the coordinate input device. It is characterized by the following. Also, preferably, the present invention is characterized in that the wrench plate has an optical characteristic region that is substantially parallel to the optical axis of the projection lens after light from the pointing tool is transmitted. Preferably, the present invention is characterized in that the optical characteristic region of the wrench plate is constituted by a convex curvature surface on the coordinate input surface side and a concave curvature surface on the image projection side.

[0024]

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

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

First, the schematic configuration of an optical coordinate input device according to the present invention will be described with reference to FIG. 1. This device is roughly divided into an indicator for forming a light spot on a screen 10 which is a coordinate input surface. 1 and a coordinate detector 1 for detecting the position coordinates and the like of the light spot 5 on the screen 10. FIG. Is displayed.

Next, the schematic structure of the pointing device 4 will be described with reference to FIG.

The indicating tool 4 includes a light emitting element 41 such as a semiconductor laser or an LED for emitting an infrared light beam, a light emitting control means 42 for driving and controlling the light emission, a plurality of operation switch means 43, and a power supply such as a battery. Means 44.
The light emission control means 42 performs light emission control in which a control signal is superimposed by ON (ON) / OFF (OFF) of light emission and a modulation method described later according to the state of the operation switch 43.

The coordinate detector 1 shown in FIG. 1 comprises a coordinate detection sensor unit 2, a controller 3 for controlling the sensor unit and calculating coordinates, a control signal detection sensor 6, and a signal processing unit 7. The controller 3 detects the coordinate position of the light spot 5 on the screen 10 and a control signal corresponding to the state of each switch of the indicator 4 described later, and communicates the information to an external connection device (not shown) by the controller 3. I have to.

The projection display device 8 shown in FIG. 1 includes an image signal processing section 81 to which an image signal is input from a display signal source which is an external connection device such as a computer (not shown), and a liquid crystal controlled by the image signal processing section 81. Panel 82, lamp 83, mirror 8
4. An illumination optical system composed of a condenser lens 85 and a projection lens 86 for projecting an image of the liquid crystal panel 82 on the screen 10 so that desired image information can be displayed on the screen 10.
Can be displayed.

In order to widen the observation range of the projected image, the screen 10 is arranged in a horizontal direction with the Fresnel plate 10-1 on the image projection side, which is made up of a Fresnel lens for making the image light beam from the projection lens 86 parallel to its optical axis. Wrench plate 10 on the coordinate input surface side made of a lenticular lens that diffuses
In addition, in order to secure an appropriate visual field range also in the vertical direction, a light diffusing agent is added to the Fresnel plate 10-.
1 and the wrench plate 10-2.

The Fresnel plate 10-1 makes the image light beam parallel to its optical axis and converts the light beam input to the screen 10 by the pointing tool 4 into the coordinates constituting the coordinate detector 1 as an image pickup means. It functions to direct the detection sensor unit 2 and the control signal detection sensor 6.

Accordingly, the coordinate detection sensor section 2 and the control signal detection sensor 6 are disposed substantially in the vicinity of the projection lens 86. More preferably, the object-side focal point of the Fresnel lens of the Fresnel plate 10-1 is adjusted to the projection side. The lens 86 is disposed so as to substantially coincide with the emission position and the positions of the coordinate detection sensor unit 2 and the control signal detection sensor 6.

FIG. 1 shows an embodiment in which the coordinate detection sensor unit 2 and the control signal detection sensor 6 which are smaller than the projection lens 86 are arranged around the projection lens 86.

The object-side focal point of the Fresnel lens of the Fresnel plate 10-1 is slightly shifted from the emission position of the projection lens 86 by the coordinate detection sensor unit 2 and the control signal detection sensor 6.
May be shifted to the position side. Actually, as described above, since the screen 10 has a diffusion characteristic, the light beam from the pointing tool 4 has a certain width, and the input of the pointing tool 4 to the screen 10 as shown in FIG. Regardless of whether the position is the position of (a) or the position of (b), the light beam from the pointing tool 4 is efficiently transmitted to the coordinate detector 1.
Can be incident on the coordinate detection sensor unit 2 and the control signal detection sensor 6.

Further, in order for the light of the light spot 5 to be incident on the coordinate detector 1 more efficiently, the light from the pointing tool 4 passes through the wrench plate 10-2 and then the Fresnel lens of the Fresnel plate 10-1. It is desirable that the wrench plate 10-2 has optical characteristics such that the wrench plate 10-2 becomes parallel to the optical axis before the light is incident on the optical axis.
A detailed description of the configuration of the wrench plate 10-2 having the region having the characteristics will be described later.

With such a configuration, character information and line drawing information are input on the screen 10 by the pointing tool 4 and the information is displayed on the projection display device 8, so that it is as if "paper and pencil". In addition to enabling input and output of information in such a relationship, the configuration is such that input operations such as button operation and icon selection can be freely performed.

Hereinafter, details of the optical coordinate input device of the present invention will be specifically described.

<Detailed Description of Pointing Tool 4> FIG. 3 is a schematic structural view of the pointing tool 4, and includes a light emitting element 41 composed of a semiconductor laser for emitting an infrared light beam, and a light emission control means 42 for driving and controlling the light emission. , A power supply unit 44, and four operation switches 43A to 43D in the embodiment of the present invention. The light emission control means 42 includes four operation switches 43
ON / OFF of light emission depending on the state of A to 43D
(Off) and a light emission control in which a control signal is superimposed is performed by a modulation method described later. FIG. 14 shows the operation mode of the pointing device 4, and the switches A to D correspond to the switches 43A to 43D in FIG. In FIG. 14,
“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. 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 switches 43C and 43D arranged at positions where the forefinger and the middle finger naturally touch, the pen down and pen button control signals become signals 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.
Thus, the operator can operate lightly and quickly by drawing a character or a figure or selecting a button or a menu at an arbitrary position on the screen 10 with one hand.

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.
, The pen-down state is established, so that a natural 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 figures are directly touched on the screen than when the characters and figures are input off the screen. The present embodiment is configured such that natural and comfortable operation can be performed even when the user is away from the screen or immediately before using the four switches, and can be used properly depending on the case. ing. 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 operating tools are operated at the same time, or a plurality of pointing tools 4 having different attributes such as color and thickness are used. Therefore, the light emission control means 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 indicator 4 to transmit a change instruction signal.
It is also possible to hold the state inside or in the coordinate detector 1 so as to transmit not the ID number but the attribute information 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 a pressure detecting means in one or both of the switches 43A and 43B, pen pressure detection is performed, and various useful signals such as transmitting this pen pressure data together with a control signal can be transmitted. is there.

When the switch 43A or the switch 43B of the indicator 4 is turned on, light emission is started, and the light emission signal is composed of a reader unit composed of a relatively long continuous pulse train and a code (such as a maker ID) following the reader unit. The information is output first in accordance with a predetermined order and format of a transmission data string including a pen ID and a control signal (see FIG. 7, LSG signal).

In this embodiment, 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 be constant for coordinate detection, and that the clock component be sufficiently large for tuning the PLL. In consideration of, for example, that there is no problem even if the redundancy is relatively high, in the present embodiment, 6-bit (64) data has the same number as 1 and 0 in a 10-bit length code, and The number of consecutive 1s or 0s is 3
It is encoded by a method of allocating to the following 108 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 other long data such as ID must be transmitted. Therefore,
In this embodiment, the first two bits are a control signal, the next two bits are a content identification code (for example, a pen pressure signal is 00, the ID is 11, etc.), and the next two bits are 24 bits as one block.
The bits are composed of these parities, and subsequently 16-bit data and 2-bit parities 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 consists of four 0s and five 1s,
Alternatively, it is easy to identify a data word by using a special code of its inverted pattern (the end of the previous block is switched depending on whether the end is 1 or 0), and the position is surely identified even in the middle of the data string. Data can be restored. 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.
Although the second frequency is set to 7.5 kHz, which is 1/8 of z, the average transmission bit rate is 2/3, that is, 5 kHz because the above-described encoding method is adopted. Further, since one block is 50 bits, 24 bits of data are transmitted at 100 Hz. Therefore, the effective bit rate excluding parity is 2000 bits / second. As described above, although the redundancy is high, it is a method that can prevent erroneous detection and facilitate synchronization with a very simple configuration.

Further, by using a phase synchronization signal for sensor control, which will be described later, and checking the repetition period of the 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 pen-up or 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 the internal configuration of the coordinate detector 1. This coordinate detector 1
Is provided with a light receiving element 6 for detecting the amount of light with high sensitivity by a condensing optical system, and two linear sensors 20X and 20Y for detecting an arrival direction of light by an imaging optical system. Light beams from the built-in light emitting element 41 receive diffused light from the light spot 5 generated on the screen 10.

<Explanation of Operation of Condensing Optical System> The light receiving element 6 is provided with a condensing lens 6a as a condensing optical system, and detects a light amount of a predetermined wavelength with high sensitivity from the entire range on the screen 10. I do. This detection output is output by the frequency detection means 71
After the detection, the control signal detecting means 72 demodulates a digital signal including data such as a control signal (a signal superimposed by the light emission control means 42 of the indicator 4).

FIG. 7 is a timing chart for explaining the operation of restoring the control signal. The data signal composed of the bit string as described above is output from the light receiving element 6 to the light output signal LS
It is detected as G and detected by the frequency detecting means 71.
The frequency detecting means 71 is configured to tune to the pulse period of the first frequency highest in the optical output signal LSG, and is used without being affected by disturbance light by being used in combination with an optical filter. Demodulate the signal CMD.
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. This first
Can be set to the same band as that of a generally used infrared remote controller. In such a case, malfunction is prevented by identifying the frequency with an ID or the like.

The modulated signal CMD detected by the frequency detecting means 71 shown in FIG. 4 is interpreted as digital data by the control signal detecting means 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 means 33. The code modulation period, which is the second frequency included in the modulation signal CMD, is detected by the sensor control means 31, and the signals are used to control the linear sensors 20X and 20Y. That is, the sensor control means 31 resets at the timing of the header section shown in FIG. 7, 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 pointing device 4.

From the modulation signal CMD, a signal LON indicating the presence or absence of an optical input and a sensor reset signal RCL activated by the signal LON are generated. While the sensor reset signal RCL is at a 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, when the control signal detecting means 72 detects the header portion and confirms that the input from the pointing device 4 has been started, not other equipment or noise, a signal indicating this confirmation is transmitted to the communication control means 33. Is transmitted to the sensor control means 31 and 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 means 32 is started.

FIG. 8 is 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. 5 shows an arrangement relationship between the two linear sensors 20X and 20Y. By the cylindrical lenses 90X and 90Y as the imaging optical system, the image of the light spot 5 is linearly formed on the photosensitive portions 21X and 21Y of each sensor.
An image is formed on 1X and 91Y. By accurately arranging these two sensors at right angles, an output having a peak at a pixel reflecting the X coordinate and the Y coordinate is obtained. These two sensors are controlled by the sensor control means 31, and the output signal is sent to the coordinate calculation means 32 as a digital signal by the AD conversion means 31A connected to the sensor control means 31 to calculate the output coordinate value, The result is transmitted to an external control device (not shown) by a predetermined communication method via the communication control means 33 together with data such as a control signal from the control signal detection means 72.

In order to perform an unusual operation (for example, setting of a user calibration value) such as adjustment, the communication control unit 33 sends the sensor control unit 31 and the coordinate calculation unit 3.
2, a mode switching signal is sent.

In the present embodiment, the focus is adjusted so that the image of the light spot 5 has an image width several times as large as the pixel of each sensor, and blur is intentionally caused. 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. An image width of 15 μm or less was obtained, and it was found that in such a state, the inter-pixel division calculation result was distorted in a stepwise manner.

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 embodiment. By using such a combination, the amount of operation data is small, and a small sensor and optical system can be used. An extremely 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, and the internal configuration is shown in FIG.

The sensor array 21 serving as a light receiving section is composed of N pixels (64 pixels in this embodiment), and charges corresponding to the amount of received light are stored in the integrating section 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 section 23 is composed of 2N pieces, and charges are separately stored corresponding to H (high level) and L (low level) of the signal LCK synchronized with the light emission timing of the indicator 4. After that, the electric charges separately accumulated in synchronization with the blinking of the light are stored in a circuit provided for simplifying the transfer clock.
The data is transferred to the 2N linear CCD units 25 via the N shift units 24.

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 signal RCL, 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.

The linear sensors 20X, 20 obtained at this time
FIG. 9 shows an example of the output waveform of Y. In the figure, 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 (shown in FIG. 6). As, ring CCD
26, the charges of the pixels corresponding to the waveforms of A and B are adjacently arranged.)

The amplifier 29 in FIG. 6 non-destructively amplifies and outputs the difference value (waveform B-A) of the adjacent charge amount, whereby the image of only the light from the indicator 4 is formed. A signal was obtained, and stable coordinate input was possible 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, if the accumulation time during which the sensor functions for light is increased, the PEAK value increases in accordance with the time. I do. In other words, if the time corresponding to one cycle of the signal LCK is defined as the unit accumulation time, and the number of accumulations n is defined in units of the accumulation time, the PEAK value increases by increasing the number of accumulations n, and the PEAK value becomes a predetermined large value. By detecting that the threshold value TH1 has been reached, 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 be used before the peak of the differential waveform BA becomes sufficiently large.
The transfer charge of D26 may be saturated. In consideration of such a case, the sensor is provided with a skim portion 28 having a skim function. The skim unit 28 monitors the level of the non-lighting signal, and in FIG.
When the signal level exceeds a predetermined value (indicated by a dashed line in the figure), a fixed amount of charge is extracted from each of the pixels A and B. Thus, in the next (n + 1) -th time, An + 1
By repeating this, even if there is extremely strong disturbance light, signal charges can be continuously accumulated without being saturated.

Therefore, even if the amount of blinking light 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, a signal of a display image 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. Become.

FIG. 11 shows a series of operations for sensor control of the linear sensors 20X and 20Y. The sensor control means 31 first starts a sensor control operation in step S101, and monitors the signal CON in step S102. When the signal CON goes high,
In step S103, the number of accumulations n is reset to 0, and in step S104, it is determined whether the PEAK value (peak level) of the sensor output is larger than a predetermined value TH1.

If less than TH1, step S10
At 5, it is determined whether the number of accumulations n exceeds a first predetermined number n0. If not, the process proceeds to step S106, and the number of accumulations n is incremented by one, and the process proceeds to step S10
Return to 4. If the PEAK value is greater than TH1 or if n exceeds n0, the process proceeds to step S107, where the integration stop signal RON becomes high level (H), and the integration operation is stopped. Then, the coordinate value calculation processing by the coordinate calculation means 32 is started.

Thereafter, step S108 and step S1
In the loop 09, when the second predetermined number of times n1 is exceeded, the integration stop signal RON goes low, and at the same time, the signal LCK
The sensor reset signal RCL is at the high level for several times (two times in FIG. 8) the cycle of the operation, and the process proceeds to step S112. This operation is repeated while the signal CON is at the high level, and the predetermined number of times n1 The coordinate value calculation is performed for each cycle determined by.

Step S111 is provided so that the state is maintained only once even if the signal CON drops due to the influence of dust or the like. If the signal CON is at the low level for two consecutive periods, step S1
From step 02, the process proceeds to step S113, where the flag pon is reset to 0, and waits for a sync signal to return to step S101.

This dropout countermeasure portion can be longer than one cycle, and needless to say, may be eliminated if there is little disturbance. 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 incorporated 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 sensor due to the posture of the pointing tool 4 is increased.

However, in this embodiment, even in such a case, the number of integrations automatically follows, and a stable output signal can always be obtained. Is obtained. When the beam of the laser pointer is incident on the sensor without being scattered much, very strong 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 type using D and a laser pointer are used together, LEDs with a larger light amount can be used. Therefore, the number of integrations n0 and n1 shown in FIG. It is also possible to switch the sampling speed in the case of a pen and the sampling speed in the case of a pointer. Actually, it is impossible to draw a delicate drawing operation like a character input with a pointer. Rather, it is more convenient to draw a smooth line by low-speed sampling, and it is effective to provide such switching.

As described above, a high-frequency carrier is added to the blinking light, and the timing of the integration operation is controlled by a demodulated signal having a predetermined period obtained by frequency-detecting the carrier. This makes it possible to synchronize with the image transfer unit cordlessly, thereby realizing a convenient coordinate input device.

Further, by using a laser beam, there is also obtained an excellent advantage that the operation can be easily performed 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 means 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. This makes it possible to always obtain a stable and high-resolution coordinate calculation result.

<Coordinate Value Calculation> The coordinate calculation processing in the coordinate calculation means 32 of FIG. 4 will be described below.

The output signals (difference signal from the amplifier 29) of the two linear sensors 20X and 20Y obtained as described above are converted into digital signals by the AD conversion means 31A provided in the sensor control means 31, and the coordinate calculation means is used. 32, and the coordinate values are calculated. First, the calculation of the coordinate value is performed by X
Coordinate values (X1, Y1) on the sensor are obtained for output data in each direction of the coordinate and the Y coordinate. The arithmetic processing is the same as X and Y, so only X will be described.

FIG. 12 shows the flow of the coordinate calculation process.

In step S201, the process starts. In step S202, difference data Dx (n), which is a difference signal of each pixel at an arbitrary coordinate input point (a predetermined point whose coordinates are known in a reference point setting mode described later). (The number of pixels n = 64 in this embodiment) is read and stored in the buffer memory. Next, in step S203, the data value Ex (n) is compared with a preset threshold value V and is equal to or larger than the threshold value.
Is derived. Using this data, a coordinate X1 on the sensor is calculated in step S204. In the present embodiment, the center of gravity of the output data is calculated by the centroid method, but it goes without saying that there are a plurality of calculation methods such as a method of obtaining the peak value of the output data Ex (n) (for example, by a differential method).

In step S205, the mode of the coordinate calculation process is determined. In order to calculate the coordinates from the center of gravity X1 of the output data, it is necessary to obtain a predetermined value in advance,
A method of deriving the predetermined value (reference point setting mode) will be described.

Similarly, if only the X direction is described, points (α1, β) on the screen 10 where the X and Y coordinates are known are known.
In 1) and (α2, β2), position the indicating tool 4 and
Run each of the foregoing steps S202 to S204, the centroid value of the X-direction sensor obtained at each point, X1 _1, X1 ₂
, And their values, and the known coordinate values α ₁ and α ₂ are stored in step 210. Using this stored value, the X coordinate of the coordinate input point to be derived in step S206 can be calculated during normal coordinate calculation. In step S207, 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 in order to correct lens aberration of the optical system). To determine the coordinate values.

It is needless to say that the determined coordinates can be output as it is in real time, or data can be thinned out (for example, only one data is output for every ten determined coordinates) according to the purpose. However, it is important when the following specifications are assumed.

The stability of the user's hand differs between when the pointing tool 4 is used like a pen and when it 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. Especially when writing characters, if a small quick operation is not possible, it becomes impossible to input 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 and whether or not the tip switch is pressed. You can determine whether you are using.

If it is a pointer, for example, the output coordinate values (X-1, Y-1) and (X-2, Y
By calculating the moving average by using -2) and obtaining the current output coordinate values (X, Y), a configuration with less blur and good operability can be obtained. In this example, a simple moving average is used. However, as a function used for such smoothing processing, other than the above, a difference absolute value is nonlinearly compressed according to a magnitude, or a prediction value based on a moving average is used. Various methods such as non-linear compression of the difference from this can be used. In short, when using as a pointer, it is possible to increase the smoothing, otherwise it is possible to switch to a weaker by the control signal, so that it is possible to realize a convenient state for each. The effect of the present invention is great.

Note that, as described above, when the coordinate sampling frequency is 100 Hz,
msec, the original data is 64 pixels x
Since 2 (x and y) × AD conversion means are as small as 8 bits and no convergence operation is required, the processing can be sufficiently performed by a low-speed 8-bit one-chip microprocessor. 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) obtained by the above-described arithmetic processing is supplied to the coordinate arithmetic means 32.
Is sent to the communication control means 33. This communication control means 3
3, the data signal and the control signal from the control signal detecting means 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. This allows
Various operations such as input of a cursor and menu on the screen 10 and input of characters and line drawings can be performed. As described above, even when a sensor with 64 pixels is used, a resolution of more than 1000 and sufficient accuracy can be obtained, and both the sensor and the optical system can be configured in a small and low-cost configuration, and the arithmetic circuit is very small. A coordinate input device that can have a large-scale configuration can be obtained.

When the sensor is configured as an area sensor, doubling the resolution requires four times the number of pixels and calculation data. On the other hand, when the sensor is configured as a linear sensor, Only needs to double the number of pixels in each of the X and Y coordinates. Therefore, it is easy to increase the number of pixels to achieve higher resolution.

As described above, according to the present invention, the difference signal is obtained by separately integrating the light-on and light-off signals of the light spot which blinks at a predetermined cycle by the indicator to obtain the difference signal. Because it is configured to obtain the position with high accuracy, it is possible to obtain high-precision, high-resolution coordinate values, furthermore, it is possible to suppress the influence of disturbance light and realize a small, lightweight, low-cost device. The effect was obtained.

<Description of Screen> The screen 10 used in the above-described apparatus will be described in detail. As described above, the screen 10 is provided with the projection lens 86.
FIG. 2A is a diagram showing a Fresnel plate 10-1 made of a Fresnel lens that makes an image light beam from the lens parallel to its optical axis and a wrench plate 10-2 made of a lenticular lens that diffuses horizontally. FIG. 2B shows a horizontal cross-sectional structure of only the wrench plate 10-2 having the features of the present invention. 2 (a) and 2 (b) show the structure of the same wrench plate 10-2 of the present invention.
2A is a diagram illustrating an optical path of an image light beam from the projection lens 86, and FIG. 2B is a diagram illustrating an optical path of a light beam from the pointing tool 4 from the coordinate input surface side. .

Reference numeral 10-2-1 in FIG. 2 denotes a lenticular lens, which diffuses the image light beam from the projection lens 86, which is made substantially parallel by the Fresnel lens, in the horizontal direction as shown. FIGS. 2A and 2B show a configuration in which lenticular lenses 10-2-1 are provided on both surfaces. Also, the lenticular lens 10-2-1 on the image projection side is an elliptical surface, and the lenticular lens 10-2-1 on the coordinate input surface side is provided so that the focal point is the emission surface. The area required for emitting the image light is reduced. In addition, by increasing the power of the elliptical surface, the wrench plate 10-2 can be made thinner, and the diffusion angle of the image light can be increased. As described above, the area of the lenticular lens 10-2-1 on the coordinate input surface side related to the diffusion of image light is configured to be small, and the convex lens 10-2 is provided in other areas.
-2 is provided. Also, the convex lens 10-2 on the coordinate input surface side at the valley of the lenticular lens 10-2-1 on the image projection side.
The concave lens 10-2-3 is provided in a region facing -2.
As shown in FIG. 1B, the shape and curvature of this lens group are formed such that light from the pointing tool 4 on the coordinate input surface side is parallel to the optical axis of the image light after transmission.

The wrench plate 10- constructed as described above according to this embodiment
2, the optical path of the image light beam from the projection lens 86 is such that, as shown in FIG. 1A, the image light beam that has entered the region A in FIG. The image light is diffused by the lenticular lens 10-2-1 to widen the viewing angle. The image light beam incident on the A 'area corresponding to the concave lens 10-2-3 on the image projection side becomes parallel light in the front direction, but has little effect on the viewing angle because of its small area.

On the other hand, as shown in FIG. 1 (b), the optical path of the light beam from the pointing tool 4 from the coordinate input surface side is changed by the pointing tool 4 incident on the B lenticular lens 10-2-1 area. Although the light beam is diffused and emitted, the light beam from the pointing device 4 that has entered the region B ', which has conventionally occupied a considerable area, is
The coordinate detector 1 is constituted by the Fresnel plate 10-1 whose position and focus have been adjusted as described above by being parallel to the optical axis of the image light by the action of the convex lens 10-2-2 and the concave lens 10-2-3. Incident on the coordinate detection sensor unit 2 and the control signal detection sensor 6 efficiently.

[0101]

As described above, according to the present invention, the image pickup means is disposed substantially in the vicinity of the projection lens of the projection type display means, and the coordinate input screen is used to set the image projection light on the image projection side to the optical axis of the projection lens. A sensor comprising a Fresnel plate having a Fresnel lens that is parallel and condenses light from the pointing device to the imaging means, and a lenticular plate having a lenticular lens on the coordinate input surface side that diffuses image projection light, It has become possible to secure a sufficient amount of light incident on the substrate.

Further, the wrench plate has a lens area in which the light from the pointing tool is parallel to the optical axis after transmission of the light from the pointing tool. Thus, it is possible to provide a high-resolution and high-performance device.

[Brief description of the drawings]

FIG. 1 is an external schematic diagram showing the overall configuration of an input / output integrated device of the present invention.

FIG. 2 is an explanatory diagram illustrating features of the screen of the present invention.

FIG. 3 is a diagram showing a schematic configuration diagram of a pointing tool 4;

FIG. 4 is a diagram showing a schematic configuration of a coordinate detector 1;

FIG. 5 is a perspective view showing an arrangement relationship of linear sensors.

FIG. 6 is a block diagram showing an internal configuration of a linear sensor.

FIG. 7 is a timing chart of signal waveforms representing an operation of restoring a control signal from an output signal of a light receiving element.

FIG. 8 is a timing chart at the end of a series of operations for restoring a control signal from an output signal of a light receiving element.

FIG. 9 is a waveform chart showing an example of an output waveform of a linear sensor.

FIG. 10 is a waveform diagram showing a skim operation of the linear sensor.

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

FIG. 12 is a flowchart illustrating a coordinate calculation process.

FIG. 13 is an explanatory diagram illustrating features of a conventional screen.

FIG. 14 is a diagram showing an operation mode of the pointing device 4.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coordinate detector 2 Coordinate detection sensor part 4 Indicator 6 Control signal detection sensor 10 Screen 10-1 Fresnel plate 10-2 Wrench plate 20X, 20Y Imaging means 21 Sensor array 22 Integrating means 28 Skim means 29 Differential means 32 Coordinate calculating means 42 Emission control means

Claims (4)

[Claims] 1. An image pickup means for generating a light spot by irradiating a predetermined position on a coordinate input screen with light from a pointing device, and inputting the coordinate of the spot from an output signal of the image pickup means. An input / output integrated device comprising a coordinate input device comprising coordinate calculation means for generating a coordinate output signal corresponding to a predetermined position on the screen, and a projection type display means for projecting and forming an image on the coordinate input screen. The image pickup means is disposed substantially in the vicinity of the projection lens of the projection display means, and the coordinate input screen is set so that the image projection light on the image projection side is parallel to the optical axis of the projection lens, and An input / output device comprising: a Fresnel plate having a Fresnel lens for condensing light on the image pickup means; and a wrench plate having a lenticular lens for diffusing image projection light on the coordinate input surface side. Body device. 2. An object-side focal point of said Fresnel lens substantially coincides with an emission position of a projection lens of said projection display means and a sensor position of said imaging means of said coordinate input device. 2. The integrated input / output device according to 1. 3. The input / output integrated device according to claim 1, wherein the wrench plate has an optical characteristic region that is substantially parallel to the optical axis of the projection lens after light from the pointing tool is transmitted. . 4. The input / output integrated device according to claim 3, wherein the optical characteristic area of the wrench plate is constituted by a convex curvature surface on the coordinate input surface side and a concave curvature surface on the image projection side. .