The present invention relates to a play assist device which shows guiding indication produced from music data to a player for guiding how to play a keyboard instrument, such as a piano, electronic piano, electronic keyboard, and organ.
Play assist devices for such keyboard instruments are known which provide guiding indication of a note to be played by means of LEDs, for example, by single light indication, at a position corresponding to each key of a keyboard instrument, so as to enable the player to play a music piece according to the guidance of the guiding indication on a display without referring to a score. This type of play assist devices is suitable for beginners who cannot read scores, but are not sufficiently functional for players who can manage to read scores and want to advance to a higher level. In this regard, a play assist device is also known which displays a part of a score of music to be played on a guide display of a liquid crystal device, and guides a player by successively showing with LEDs the relevant positions on the score and on the key to be played (e.g., see Patent Publication 1). With this play assist device, the relationship between notes on a score and keys of a keyboard is expressly shown, and the ability of players to read scores may be expected to be improved.
As another type of a play assist device for keyboard instruments, there is also known a device for guiding fingering. A keyboard instrument is ideally played with ten fingers of the right and left hands. If a player plays according to a play assist device with only one finger, his/her skill may not be expected to be improved. Fingering gives directions on which note is to be played with which finger, and is usually indicated on a score by numbers from 1 to 5 each assigned to each finger from the thumb to the little finger. A play assist device using this is also known which provides a guide in fingering not only by indicating the numbers for fingering near the notes or on the score shown on the guide display, but also by displaying an image of fingers to indicate which finger should be used to press a key (e.g., see Patent Publication 2).
Incidentally, aside from the discussion about play assist devices, there are known, as general display means using light, liquid crystal displays (LCDs) and electroluminescence (EL) having light sources such as incandescent bulbs, fluorescent tubes, cold-cathode tubes, light emitting diodes (LEDs), or laser diodes (LDs), as well as stereo image reproduction apparatus for displaying an image stereoscopically (e.g., see Patent Publication 3), hologram devices (e.g., see Patent Publication 4), or electric holography technique developed by NHK SCIENCE & TECHNOLOGY RESEARCH LABORATORIES.
In the conventional play assist devices which display a score, however, the LCD display for this purpose is merely of such a size as to display a score by one measure. In addition, the player cannot see both the keyboard and the displayed score simultaneously, so that he eventually relies on the light of the LED and the like which is lit at a position corresponding to the key to be pressed.
The present invention aims to solve such conventional problems. It is an object of the present invention to provide a play assist device which enables a player to learn efficiently how to read and play a score.
In order to achieve the above object, according to the present invention, there is provided a play assist device comprising: display means for displaying upper and lower staves of a grand staff independently by a predetermined range; projecting means for projecting images of said upper and lower staves of a grand staff above or onto a keyboard; pressed key detection means for detecting a pressed key; and control means for shifting said upper and lower staves so that a note to be played in the upper and lower staves is located at a position above or on a keyboard corresponding to said note. With this structure, according to music data containing information about notes and musical notation on the score of music to be played, the control means causes the display means to display a desired number of measures of the upper and lower staves of a grand staff, for example, two measures including the measure to be played now and the measure to be played next, and every time each measure is played, the display is renewed sequentially. The control means also determines whether or not to shift the upper and lower staves according to a play mode, wherein the conditions for shifting the upper and lower staves have been set up. When the control means decides to shift the upper and lower staves, it does so that the note to be played in the upper and lower staves is located at a position above or on the keyboard corresponding to the note. Thus the player may easily see the physical correspondence between the position of a note on the score shown on the display means and the position of a key of the keyboard to be actually pressed, which assists the player to clearly understand the positional relationship between the notes and the keys to be pressed. As a result, the player may efficiently learn how to read and play a score, and easily learn a skill to play from the score without relying on the play assist device.
Incidentally, the upper staff of a grand staff is a treble clef staff, and the lower staff a bass clef staff.
According to the present invention, the display means is also characterized by displaying an image of fingers at a position on the keyboard corresponding to the note to be played in the upper and lower staves. With this feature, the positional relationship between the notes and the keys to be pressed is specified, so that the player may efficiently learn how to read and play a score.
According to the present invention, the control means is also characterized by determining whether or not to proceed with the music data in accordance with a play mode, wherein the conditions for proceeding with the music data have been set up. With this feature, the control means may proceed with the music data sequentially according to the play mode, irrespective of the determination of the state of play, or proceed with the music data except when the player does not press a key even after the lapse of the time period designated by each note in the music data or of a predetermined period of time, or except when the player presses a wrong key.
According to the present invention, the play assist device further includes position adjusting means for adjusting the position of the images of the upper and lower staves projected above or on the keyboard. With this feature, the position of the score image and the like projected above or on the keyboard may be changed and adjusted to a position easily visible to the player. The same is true for a fingering mark or an image of fingers.
According to the present invention, at least the measure to be played now and the measure to be played next of the upper and lower staves of a grand staff are displayed, and every time the measure to be played now is finished, the measure to be played next is displayed as a new measure to be played now. With this feature, the player may always see not only the notes contained in the measure to be played now, but also the notes in the measure to be played next while he plays.
According to the present invention, information about the position on the keyboard corresponding to each note in the upper and lower staves of a grand staff, and information about a distance between notes in the upper and lower staves are stored in advance, and the control means shifts the upper and lower staves in accordance with the stored information about the position on the keyboard and the information about the distance. With this feature, the control means may shift the upper and lower staves, when desired, so that the note to be played is located at a position on or above the key to be pressed corresponding to the note. Incidentally, as used herein, the term “information about a distance” means information for shifting the upper and lower staves displayed on the display means or information for adjusting the position or angle of the display means or the projecting means.
According to the present invention, the control means measures the time from causing display of the upper and lower staves until the pressed key detection means detects pressing of a key, and reflects the measured time to the play mode. With this feature, a play mode may be set automatically depending on the state of play of the player, so that the player may efficiently learn how to read and play a score.
According to the present invention, the control means synchronizes duration of notes in the upper and lower staves in the music data by the measure, and when a note in the upper staff is to be played simultaneously with a note in the lower staff, the control means proceeds with a subsequent process only when it acquires both of the notes via the pressed key detection means detecting corresponding keys. This feature allows the player to play the upper and lower staves in the music data in synchronization with each other, so that the player may efficiently learn how to read and play the upper and lower staves.
According to the present invention, the play assist device may be set to automatically play the upper or lower staff of the grand staff. With this feature, it is possible to set the lower staff to be played automatically when the player is to play only the upper staff, or to set the upper staff to be played automatically when the player is to play only the lower staff, so that the player may efficiently learn how to read and play the upper and lower staves.
According to the present invention, the control means synchronizes display of notes to be played simultaneously when the upper and lower staves contain notes of different values. This feature allows the player to play the upper and lower staves in synchronization, so that the player may efficiently learn how to read and play the upper and lower staves.
As discussed above, the play assist device according to the present invention comprises display means for displaying upper and lower staves of a grand staff independently by a predetermined range; projecting means for projecting images of the upper and lower staves of a grand staff above or onto a keyboard; pressed key detection means for detecting a pressed key; and control means for shifting the upper and lower staves so that a note to be played in the upper and lower staves is located at a position above or on the keyboard corresponding to the note. With this structure, according to music data containing information about notes and musical notation on the score of music to be played, the control means causes the display means to display a desired number of measures of the upper and lower staves of a grand staff, for example, two measures including the measure to be played now and the measure to be played next, and every time each measure is played, the display is renewed sequentially. The control means also determines whether or not to shift the upper and lower staves according to a play mode, wherein the conditions for shifting the upper and lower staves have been set up. When the control means decides to shift the upper and lower staves, it does so that the note to be played in the upper and lower staves is located at a position above or on the keyboard corresponding to the note. Thus the player may easily see the physical correspondence between the position of a note on the score shown on the display means and the position of a key of the keyboard to be actually pressed, which assists the player to clearly understand the positional relationship between the notes and the keys to be pressed. As a result, the player may efficiently learn how to read and play a score, and easily learn a skill to play from the score without relying on the play assist device.
A first embodiment of the play assist device according to the present invention will be explained. Referring to
The dot matrix display 41 is vertically segmented into three areas, 41a, 41b, and 41c, with the first area 41a displaying a score, various messages, or the like, the second area 41b displaying fingering marks m, and the third area 41c displaying an image of fingers. The lens plate 42 is similarly segmented into fly's eye lens 42a corresponding to the first area 41a of the dot matrix display 41, single lens array 42b corresponding to the second area 41b, and space 42c corresponding to the third area 41c. In another embodiment, the lowermost third area 41c of the dot matrix display 41 and the lowermost space 42c of the lens plate 42 may be dispensed of. In yet another embodiment, the projecting means maybe provided corresponding to the second area 41b only, and not to the first area 41a. In addition, a position adjusting function may be provided for moving and adjusting the positions of the image of a score and the like, the fingering marks, or the image of fingers projected above the keyboard, into positions easily viewable to the player. The position adjusting function may include adjustments of the position or the angle of the dot matrix display 41 or the lens plate 42, and provided on either or both of these. A finger screw may be provided on either or both lateral ends of the dot matrix display 41 and/or lens plate 42, and the position and the angle of the dot matrix display 41 and/or the lens plate 42 may be adjusted by manipulating the screws. In this way, the image of a score and the like, the fingering marks, and the image of fingers projected above the keyboard may be moved and adjusted to a position viewable to the player, e.g., from the front to the rear of the keyboard 2 as seen by the player. Incidentally, the means for the three-dimensional display are not limited to the display means and the projecting means as discussed above, and may suitably be modified.
The score displayed in the first area 41a is a predetermined range of the upper staff (treble clef staff) and the lower staff (base clef staff) of a grand staff displayed independently from each other and in accordance with the music data stored in the memory of the play assist device 3. The music data includes note information, such as note values and tone pitch, and musical notation information, such as rhythm and sound intensity, which are obtained by loading the upper staff (treble clef staff) and the lower staff (base clef staff) of an original grand staff as image data, and matching the notes, musical notation, and the like shown in the loaded image data. At least the measure to be played now and the measure to be played next of the upper and lower staves are shown, and every time the measure to be played now is finished, the measure to be played next is shown as a new measure to be played now. In this way, the player may visually observe not only the notes contained in the measure to be played now, but also the notes in the measure to be played next, while he plays. In addition, a measure having played in the past of the upper and lower staves may also be displayed. In this way, the player may also visually observe a measure having played in the past. The fly's eye lens 42a of the lens plate 42 corresponds to the first area 41a, and the two together form a three-dimensional display which forms, above the keyboard 2, a virtual stereo image 43, such as an image of the notes and the like displayed in the first area 41a.
In this way, image data of the upper and lower staves of a grand staff to be displayed in the first area 41a is respectively formed, for example, in advance by the measure, associated with music data containing information about the value and pitch of each note on the score and information about musical notation, such as rhythm and intensity, and stored in a memory. The stored image data is suitably selected via a liquid crystal driver, and displayed in the first area 41a of the dot matrix display 41 as shown in
The fingering mark m displayed in the second area 41b of the dot matrix display 41 is displayed correspondingly at a position of the key to be pressed as shown in
Alternatively, the second area 41b does not have to be configured as part of the dot matrix display 41, but may be formed as LED array 46 as shown in
Referring to
A hologram display utilizing this rainbow hologram technique according to an embodiment of the present invention will be discussed. First, a master hologram is produced by capturing, by means of a CCD camera as the master hologram plate 112 in
The guide display 4 is configured as discussed above. In the above discussion, the score displayed in the first area 41a has been explained as being displayed in three dimensions, but two dimensional display may also be conceivable. For example, an image of the upper and lower staves of a grand staff may be displayed in two dimensions by providing a small sized dot matrix display of high integration density having dots at least comparable in number to those of the first area 41a of the dot matrix display 41, and providing, as shown in
In this way, the image data of the upper and lower staves of a grand staff is respectively formed, for example, in advance by the measure, and stored in a memory. The stored image data is suitably selected via a liquid crystal driver, displayed on the transmissive LCD 51, and projected through the toric lens 52, so that the reproduced image is displayed in two dimensions the keyboard 2 as shown in
The external memory 15 stores music data as discussed above. The music data has been created in accordance with the value and pitch of each note on a score of a piece to be played by a player, rhythm and sound intensity according to each musical notation, and the like. When being stored, the music data is associated with respective image data of the upper and lower staves and image data of fingers to be displayed on the dot matrix display 41. In this way, the image data of the respective upper and lower staves and the image data of fingers may be displayed in synchronization with the progress of the music data.
In the pressed key detection unit 16, a transmission or reflective photocoupler is used to detect positional displacement of a pressed key, to thereby detect pressing and/or releasing of a key.
The state-of-play determination unit 17 acquires play data, such as the position of a key 2 pressed by the player (sound pitch), the duration of sound from pressing to release of a key (note value), rhythm, intensity, and the like, via the pressed key detection signal obtained by the control unit 12, and compares the acquired play data with the music data acquired from the RAM 14 through the control unit 12, to thereby determine the state of playas needed. The result of the determination is sent to the control unit 12, and when, for example, the play data is faster than the music data, the control unit 12 causes the first area 41a of the dot matrix display 41 to display “PLAY MORE SLOWLY” or the like for notification to the player.
The operation input unit 18 designates a play mode and instructs what is to be displayed, through a mouse, trackball, pad, or keyboard. The operation input unit 18 may be provided on the front surface of the dot matrix display 41 as a touch panel on which a player may write with a light pen and/or a finger. The play mode sets the processing to be done by the control unit 12 according to a play level, and includes the predetermined conditions for proceeding with the music data, shifting the upper and lower staves, and the like. The control unit 12 determines the progress of the music data and the shift of the upper and lower staves, according to the established play mode. For example, a play mode for advanced players is set so that the control unit 12 sequentially proceeds with the music data independent of the play state determined by the state-of-play determination unit 17, and the upper and lower staves are not shifted. A play mode for intermediate players is set so that the music data sequentially proceeds except when the state of play determined by the state-of-play determination unit 17 indicates that the player does not press a key even after the lapse of the time designated by a note in the music data or of a predetermined time period, or the player presses a wrong key, and when the player does not press a key even after the lapse of the time designated by a note in the music data or of a predetermined time period, or the player presses a wrong key, the upper and lower staves are shifted so that the note to be played is positioned on or near the corresponding key. A play mode for beginners is set so that the music data sequentially proceeds except when the state of play determined by the state-of-play determination unit 17 indicates that the player does not press a key even after the lapse of the time designated by a note in the music data or of a predetermined time period, or the player presses a wrong key, and the upper and lower staves are shifted so that the note to be played is always positioned on or near the corresponding key.
The control unit 12 shifts the upper and lower staves, when desired, so that the note to be played is positioned above or on the corresponding key. In order for the control unit 12 to process the shift, the external memory 15 stores in advance information about the position of a key corresponding to each note and the distance between adjacent notes in the music data. For example, when the music data contains notes “D”, “F”, and “E” in this order, the information about the key position is stored in numerals, i.e., “2”, “4”, and “3”, and the information about the distance between adjacent notes is stored as a difference between the positional information of the adjacent notes, i.e., “+2” and “−1”. In this way, the upper and lower staves may be shifted, when desired, by the control unit 12, so that the note to be played is positioned above or on the corresponding key. In addition, the external memory 15 stores in advance information about the position of a key corresponding to the pitch. For example, according to the pitches “C, D, E, F, G, A, B, C”, information about the key positions is stored in numerals, i.e., “1, 2, 3, 4, 5, 6, 7, 8”. The control unit 12 may acquire information about the distance between notes in the upper and lower staves from the difference between the pitch of the note currently being played (e.g., “4” for F) and the pitch of the note to be played next (“3” for E) (the difference being “−1”) or the pitch of the note previously played (“2” for D) (the difference being “+2”). In this way, the upper and lower staves may be shifted by the control unit 12, when desired, so that the note to be played is positioned above or on the corresponding key. Incidentally, as used herein, the information about the distance means information for shifting the upper and lower staves displayed on the dot matrix display 41 or for adjusting the position and angle of the dot matrix display 41 and the lens plate 42. The control unit 12 inputs the information about the distance to the liquid crystal drive 11, by which the latter drives shift of the image data of the upper and lower staves displayed on the dot matrix display 41, or adjustment of the position and angle of both or either of the dot matrix display 41 (or the transmissive LCD 51) and the lens plate 42 (or the toric lens 52) (see
Next, specific examples of the play assistance using the play assist device 3 of the present invention will be explained for each play level. According to the present embodiment, the player may arbitrarily choose via the operation input unit 18 a play mode from Level 1 to Level 5 as follows, according to the skill of the player.
Level 1: Level 1 is for advanced players. The first area 41a sequentially displays the upper and lower staves of a grand staff by an arbitrary number of measures, e.g. by two measures, and the image thereof is projected onto the display position corresponding to the space above or the surface of the keyboard 2 in the approximate center thereof. As means for highlighting the note to be played now, aside from the blinking display as shown in
Level 2: Level 2 is for intermediate players, and is applied when the player does not press a key even after the lapse of the time designated by a note in the music data or of a predetermined time period, or the player presses a wrong key. In this Level 2, an image of a grand staff is initially displayed at the display position in approximately the center of the keyboard 2 as in Level 1. When the player does not press a key even after the lapse of a predetermined time period, or the player presses a wrong key, the image of the upper staff is shifted to near the position of the key supposed to be pressed with a right hand finger, and the lower staff near the position of the key supposed to be pressed with a left hand finger. That is, the approximate position of the key to be pressed is shown to the player so that he could confirm which key is to be pressed. Here, the distance between the notes in the image of the upper and/or lower staff may be made smaller than the width of a key to be pressed so that a plurality of notes are shown within the width. In this way, the player may be given an opportunity to think which note corresponds to which key, which improves his score reading ability.
Level 3: Level 3 is for intermediate players lower than Level 2, and is applied when the player does not press the key corresponding to the note to be played even after the lapse of the designated time or of a predetermined time period, or the player presses a wrong key. In this Level 3, an image of a grand staff is initially displayed at the display position in approximately the center of the keyboard 2 as in Level 1. When the player does not press a key even after the lapse of a predetermined time period, or the player presses a wrong key, the image of the upper staff is shifted to the key corresponding to the note supposed to be played with a right hand finger, and the lower staff to the key corresponding to the note supposed to be played with a left hand finger, as shown in
Level 4: Level 4 is for beginners lower than Level 3, and is applied when the player does not press a key even after the lapse of the time designated by a note in the music data or of a predetermined time period, or the player presses a wrong key. In this Level 4, an image of a grand staff is initially displayed at the display position in approximately the center of the keyboard 2 as in Level 1. When the player does not press a key even after the lapse of a predetermined time period, or the player presses a wrong key, the image of the upper staff is shifted to the key corresponding to the note supposed to be played with a right hand finger, and the lower staff to the key corresponding to the note supposed to be played with a left hand finger, as shown in
Level 5: Level 5 is for beginners still lower than Level 4. From the start of the play, as shown in
The player chooses one of the play modes of Levels 1 to 5 discussed above at the start of his play, but may change the mode even in the middle of the play. The control unit 12 may measure the time from causing display of the upper and lower staves until the pressed key detection unit 16 detects the key, and reflect the measured time to the play mode. That is, the play mode may be set and changed automatically in accordance with the state of play of the player. For example, in accordance with the state of play of the player, the play mode may be changed automatically from Level 1 through Level 2 to Level 3. In this way, the player may efficiently learn how to read and play a score. Incidentally, in this embodiment of the present invention, for the sake of convenience in explanation, the play level has been graded in five stages for the discussion of the set up of the conditions for the progress of music data or shift of the upper and lower staves. However, more detailed, various conditions may be set. For example, it is conceivable to set the conditions so that the player plays only the upper or lower staff. When the player plays only the upper staff, the lower staff may be set to be played automatically, whereas when the player plays only the lower staff, the upper staff may be set to be played automatically. In a lower level, it is conceivable to set the conditions so as to be switched to automatic playing to automatically conform to the progress of music data.
It may be made optional to return the image of a score to the initial, central display position when the player presses a correct key. In displaying a score in the first area 41a, the measure currently being played may be displayed in color, and the background color of the measure may be changed sequentially according to the progress of the notes, while the changing color may blink to the tempo represented by a metronome marking, so that the player may feel the tempo of the music. When a plurality of notes are highlighted to play, i.e., in case of a chord or polyphony, the correspondence between the highlighted notes and the actual keys to be pressed may be indicated so that the highlighted notes stay above a key most suitable for fingering. For example, when the music data contains notes representing a chord or polyphony, it is preferred to configure the settings so that each of the notes is displayed at its corresponding key. The control unit 12 may synchronize the duration of notes in the upper and lower staves by the measure, and when a note in the upper staff is supposed to be played simultaneously with a note in the lower staff, the control unit 12 proceeds with the subsequent process only when it acquires both of the notes via the pressed key detection unit 16 detecting the corresponding keys. This allows the player to play the upper and lower staves in the music data in synchronization with each other, to learn efficiently how to read and play the upper and lower staves. In other words, the upper and lower staves in the music data are set to synchronize for each measure, and when certain notes in the music data are supposed to be played with the right and left hands simultaneously, the control unit 12 takes it as an error to press only a key corresponding to the note in the upper staff or to press only a key corresponding to the note in the lower staff. Only when both of the notes are acquired via the pressed key detection unit 16 detecting the corresponding keys, the control unit 12 proceeds with the subsequent process. In this way, the music data may proceed, with the upper and lower staves in synchronization with each other for each measure, and the player may learn efficiently how to read and play the upper and lower staves. In the score displayed in the first area 41a, the order of the notes to be played may be indicated based on the information about the notes and the musical notation in the music data. In this way, the player by himself may play the upper and lower staves in synchronization with each other, and efficiently learn how to read and play a score. As shown in
As discussed above, with this embodiment, according to the music data containing information about notes and musical notation in the piece of music to be played, the display means displays a desired number of measures of the upper and lower staves of a grand staff, for example, two measures including the measure to be played now and the measure to be played next, and every time each measure is played, the display is renewed sequentially. It is determined whether or not to shift the upper and lower staves according to the play mode, wherein the conditions for shifting the upper and lower staves are established. The upper and lower staves are shifted, when desired, so that the note to be played is located at a corresponding position above or on the keyboard. Thus, the player may easily see the physical correspondence between the position of a note on the score shown on the display means and the position of a key of the keyboard to be actually pressed, which assists the player to clearly understand the positional relationship between the notes and the keys to be pressed. As a result, the player may efficiently learn how to read and play a score, and easily learn a skill to play from the score without relying on the play assist device. In accordance with the progress of the music data, after the pressed key detection unit 16 detects the key-pressing motion of the player, the position of the key supposed to be pressed next may be indicated sequentially with a fingering mark m and an image of fingers. Since such guiding indications are projected onto the corresponding key by means of the lens plate 42 arranged in the front, the player may see the keyboard to play with correct fingering. By comparing the play data detected by the pressed key detection unit 16 and the corresponding music data stored in the RAM 14, the state-of-play determination unit 17 can determine the state of play of the player, and continually determine as the music data proceeds whether the player can play correctly not only the pitch but also the intensity, duration, slur, staccato, tenuto, and the like, without interrupting the play. Thus automatic guidance of higher quality for playing an instrument may be realized.
In the present embodiment, notes and a score are displayed in the first area 41a in the uppermost section of the dot matrix display 41, a fingering mark in the second area 41b, and an image of fingers in the third area 41c as required, but this order may arbitrarily be changed, and notes and a score may be displayed in the lowermost third area. Alternatively, an image of fingers may be displayed in the first area 41a of the integral photography, and notes and a score in the third area 41c of the hologram display.
In the present embodiment, three-dimensional display technology is employed in the first area 41a to display a virtual stereo image. Instead, the first area 41a of the dot matrix display 41 may be made as an ordinary LCD dot matrix display and display a score thereon, a lens array having lenses corresponding to the respective keys of the keyboard 2 is arranged corresponding to and in front of this LCD dot matrix display, and a note on the score displayed on the LCD dot matrix display may be projected as an image of a note onto a corresponding key to be pressed. Since both the upper and lower staves of a grand staff are displayed on the LCD dot matrix, the lens array is correspondingly arranged in two rows or in partially separated two columns on right and left side of the middle C, so that both staves may be projected onto the keyboard 2. Even in this case, the guiding indication is not hidden by the hands of the player. Even if displayed at a position where it could be hidden by the hands of the player, the guiding indication is in practice projected onto the hands, so that the player may play, watching the guiding indication projected on his hands. The corresponding lens element itself of the lens array also sheds light, so that the guiding indication may be observed on the lens element. For the lens array, one-to-one erect imaging lens array or the like may be used. In any case, the guiding indication will not be hidden by the hands, and the player may play, watching the guiding indication, so that he can easily play even a piece which he has never played before.
In the discussions above, the fingering mark m displayed in the second area 41b is projected onto an appropriate key by the single lens array 42b. In this case, the position of the projected mark depends on the position of the first area 41b and the single lens array 42b, and the tilt and the focal length of each lens element of the single lens array 42b. Thus the single lens array 42 may be made independent from other parts, and mounted for back-and-forth tilting motion around the rotation axis provided on both sides in the center or lower part of the lens array, so that the position of projection may be adjusted. By adjusting the focal length and the tilt angle of the single lens array 42b, the fingering mark may be projected onto the overall surface of a relevant key. The fingering mark may, by default, point to the middle C key of the keyboard 2 upon power-on of the play assist device.
In the embodiments discussed above, a liquid crystal device is used as display means, but the dot matrix display 41 may be composed of light emitting diodes, organic EL, laser diodes, plasma, or the like. The projecting means may be a pinhole. The LCD may suitably be selected from transmissive LCD, reflective LCD, backlight LCD, or combinations thereof, depending on the state of use of each area.
Number | Date | Country | Kind |
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2007-161414 | Jun 2007 | JP | national |