JP2008009074A - Display device and display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To excellently display an image, when a light beam is to be scanned using a projector. <P>SOLUTION: A laser beam modulated by an image signal constituted of odd frames and even frames is emitted, the emitted laser beam is two-dimensionally scanned in the horizontal oscillation direction and the vertical oscillation direction of the image, and the scanned laser beam is projected to display an object to be displayed. As scanning, the scanning locus of the image signal of the odd frames (Fig. 5(a)) and the scanning locus of the image signal of the even-numbered frames (Fig. 5(b)) are set inverted in phase to each other, and the beginning positions of describing of the respective frames are set to be different from each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device and method suitable for application to a projector device that scans using, for example, a scanning device that performs reciprocal scanning of a laser beam emitted from a laser light source and displays an image on a screen.

  Conventionally, in order to project an image on a screen, for example, an LCD (Liquid Crystal Display) type projector apparatus has been put into practical use. The LCD projector device transmits or reflects light from a light source by an LCD panel that displays an image, and projects the transmitted or reflected light on a screen. On the other hand, in recent years, a technique for performing two-dimensional scanning on a screen using a resonant optical scanner such as a MEMS (Micro Electro Mechanical Systems) device has been proposed in order to reduce the size of a projector apparatus. In this case, laser light is used as a light source, the laser light is directly modulated with an image signal, and then the modulated laser light is two-dimensionally scanned with a resonance type optical scanner.

  When a laser light source is used as the light source of the projector device, the size of the light source can be made smaller than before. For this reason, it has become possible to reduce the overall size of the projector apparatus by replacing a large-sized light source, such as a xenon lamp or an ultrahigh pressure mercury lamp, which has been conventionally used as a light source in the projector apparatus, with a laser apparatus. .

Patent Document 1 describes a technique for displaying an image on a screen using a semiconductor laser.
Japanese Patent Laid-Open No. 2002-357883

  By the way, horizontal scanning of a laser beam using a resonance type optical scanner is performed by a sine wave. And the direction which a laser beam scans horizontally is not a one-side direction but a reciprocating direction. For this reason, the scanning line drawn by the laser beam has a different inclination depending on the direction. Here, an example of the inclination of a scanning line drawn by conventional scanning will be described with reference to FIG. When horizontal scanning is performed using a resonance type optical scanner, among the scanning lines of the laser beam for one cycle of the sine wave, the scanning line T1 in the first half cycle is lowered to the right, and the scanning line T2 in the latter half cycle is lowered to the left. For this reason, the vertical spacing of the scanning lines at the right end R1 of the screen is close. On the other hand, the vertical spacing of the scanning lines at the left end L1 of the screen becomes rough. Further, since the horizontal scanning of the laser beam is performed in the reciprocating direction, the scanning lines repeat the same pattern as the scanning lines T1 and T2. Then, the upper and lower intervals of the scanning lines at the right end portion R2 become sparse. On the other hand, the upper and lower intervals of the scanning lines at the left end L2 of the screen become dense.

  As a result, the intended resolution is obtained because the distance between the upper and lower scanning lines is substantially constant at the center of the screen. However, since the vertical intervals of the scanning lines can be unevenly distributed at the left and right ends of the screen, only about half the intended resolution can be obtained.

  The present invention has been made in view of such circumstances, and an object of the present invention is to display an image satisfactorily when scanning a light beam using a projector device.

The present invention modulates and emits a laser beam with an image signal composed of odd frames and even frames, and two-dimensionally scans the emitted laser beam with horizontal and vertical vibrations of the image. The present invention is applied to one that projects a scanned laser beam and displays it.
For scanning, the scanning trajectory of the odd-numbered frame image signal and the scanning trajectory of the even-numbered frame image signal at the time of scanning are set to the inverted phase, and the drawing start position of each frame is set to a different position.

  By doing so, different positions are scanned by the even-line scan lines and the odd-frame scan lines.

Further, the present invention modulates and emits a laser beam with an image signal comprising one frame of an odd field and an even field, and the emitted laser beam is divided into a horizontal vibration and a vertical vibration of an image. The two-dimensional scanning is applied to the one that projects the scanned laser beam and displays it.
As the scanning, the phase of the scanning trajectory of the odd-numbered field image signal and the scanning trajectory of the even-numbered field image signal at the time of scanning is set to be reversed, and the drawing start position of each field is set to a different position.

  By doing so, different positions are scanned by the even-line scan lines and the odd-field scan lines.

  According to the present invention, different positions are scanned by the even-line scan lines and the odd-frame scan lines, so that the screen is scanned more densely than when scanning at the same phase in each frame. The display image resolution can be improved. In particular, there is an effect that it is possible to suppress resolution degradation at the left and right ends of the screen.

  Also, since even-numbered field scanning lines and odd-numbered field scanning lines scan different positions, the screen is scanned more densely than when scanning in the same phase in each field. The resolution can be improved. In particular, there is an effect that it is possible to suppress resolution degradation at the left and right ends of the screen.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. The present embodiment is an example applied to a projector device that scans a laser beam emitted from a laser device on a screen and displays an image.

  First, an example of the overall configuration of the projector apparatus 100 will be described with reference to FIG. The projector device 100 includes an image signal supply device 1 that performs a conversion process on an image signal, supplies the image signal converted by the image signal supply device 1 to a light source 2 that emits a laser beam, and performs a modulation process on the laser beam. Applied. The light source 2 is a semiconductor laser device, for example. The laser beam emitted from the light source 2 is reflected by the two-axis MEMS scanner 10 configured to scan with two axes of a main axis and a sub-axis orthogonal to the main axis. The laser beam reflected by the two-axis MEMS scanner 10 is projected onto a two-dimensional plane screen 4 via a projection optical system 3 composed of a lens, a mirror and the like, thereby displaying an image. The biaxial MEMS scanner 10 includes a scan mirror on the main axis, and performs horizontal scanning and vertical scanning. The scanning direction 7 of the main axis is the horizontal direction of the screen 4, and horizontal resonance vibration of the sine wave 5 is performed. This horizontal resonance vibration is performed in synchronization with the horizontal frequency of the image signal. The scanning direction 8 of the secondary axis is the vertical direction of the screen 4, and the vertical resonance vibration of the sawtooth wave 6 is performed. This vertical resonance vibration is performed in synchronization with the vertical frequency of the image signal.

  In the projector apparatus 100 of this example, the laser beam emitted from the light source 2 is two-dimensionally scanned by the two-axis MEMS scanner 10 using the horizontal vibration and the vertical vibration of the image. Then, the scanning trajectory of the odd-numbered frame image signal and the scanning trajectory of the even-numbered frame image signal are set to the inverted phases. Further, the drawing start position of each frame is set to a different position by the biaxial MEMS scanner 10. In this way, an image is displayed by scanning an odd frame and an even frame obtained by inverting the phase of the odd frame. The details of the odd frame scan and the even frame scan will be described later.

  Next, an example of the external configuration of the biaxial MEMS scanner 10 will be described with reference to FIG. The biaxial MEMS scanner 10 includes a scan mirror 18 that reflects a laser beam, a rectangular inner frame portion 19 that supports the scan mirror 18, a rectangular outer frame portion 20 that supports the inner frame portion 19, and an inner frame. It is comprised with the sub-axis electromagnetic drive magnets 11a and 11b which drive the part 19 electromagnetically. The scan mirror 18 and the inner frame portion 19 oscillate around the directions orthogonal to each other. In this example, the axis that vibrates the inner frame portion 19 is the secondary axis, and the axis that vibrates the scan mirror 18 is the main axis. The countershaft electromagnetic drive magnets 11 a and 11 b are configured to sandwich the outer frame portion 20.

  The outer frame portion 20 is formed with auxiliary shaft torsion bars 12 a and 12 b that support the inner frame portion 19 in the direction of the rotation axis of the inner frame portion 19. The countershaft torsion bars 12 a and 12 b are members that support the inner frame portion 19 so as to be twisted to the left and right by a certain angle, and are integrally formed with the outer frame portion 20.

  In the vicinity of the apex in the diagonal direction of the outer frame portion 20, auxiliary shaft electrodes 14 a and 14 b serving as current input / output portions are provided. A conductive wire connected to the countershaft electrode 14 a is laid on the inner frame portion 19 via a countershaft torsion bar 12 a that supports the inner frame portion 19. The conducting wire disposed in the inner frame portion 19 forms the secondary shaft electromagnetic drive coil 13 of several turns along the edge of the inner frame portion 19. And a conducting wire is connected to the countershaft electrode 14b via the countershaft torsion bar 12b.

  The inner frame portion 19 generates an electromagnetic force when an AC voltage (driving frequency is 60 Hz, for example) is applied to the auxiliary shaft electrodes 14a and 14b from an AC power source (not shown), and the auxiliary shaft torsion bar 12a. , 12b is vibrated by the twisting action. The driving method of the secondary shaft is electromagnetic, the vibration method is non-resonant, and the vibration waveform is a sawtooth wave.

  The outer frame portion 20 includes main shaft electrodes 15a and 15b in the vicinity of the apex in the diagonal direction different from the diagonal direction of the sub shaft electrodes 14a and 14b. A conductive wire (not shown) is connected from the main shaft electrode 15 a to the inner frame portion 19 via a sub shaft torsion bar 12 b that supports the inner frame portion 19.

  The inner frame portion 19 is provided with main shaft torsion bars 16 a and 16 b that support the scan mirror 18 in the direction of the rotation axis of the scan mirror 18. The main shaft torsion bars 16 a and 16 b are members that support the scan mirror 18 so as to be twisted to the left and right by a certain angle, and are integrally formed with the inner frame portion 19. On both sides of the main shaft torsion bars 16a and 16b, rotation-side electrodes 17a and 17b, which are fine electrodes, are formed like comb teeth.

  Further, a fine electrode fixed side electrode having a comb-like shape is formed on the inner frame portion 19 so as to mesh with the respective rotation side electrodes 17a and 17b. The conducting wire connected to the inner frame portion 19 is connected to the main shaft electrode 15b via the sub shaft torsion bar 12b.

The almost elliptical scan mirror 18 is an SOI (Silicon On Insulator) substrate in which an oxide layer such as silicon dioxide (SiO ₂ ) and a semiconductor film such as silicon are sequentially laminated on the surface of a holding substrate made of, for example, silicon. Thus, the semiconductor substrate is formed by removing the holding substrate and the oxide layer selectively. The flat surface of the semiconductor film is used as the scan mirror 18 that becomes the light incident surface. A reflective film such as aluminum (Al) or gold (Au) is formed on the flat surface of the scan mirror 18 to increase the reflectance.

  The scan mirror 18 is driven by applying an AC voltage substantially equal to the resonance frequency of the scan mirror 18 (drive frequency is, for example, 16 kHz) to the spindle electrodes 15a and 15b from an AC power source (not shown). The main shaft torsion bars 16a and 16b vibrate due to the twisting action. The driving method of the main shaft is an electrostatic method, the vibration method is a resonance method, and the vibration waveform is a sine wave.

  Next, a configuration example of the image signal supply device 1 that supplies an image signal to the light source 2 will be described with reference to FIG. First, an image signal is supplied to the image signal supply device 1 from an image signal source (not shown). The image signal supply apparatus 1 includes an input unit 21 as an input unit for an image signal, and supplies the input image signal to a horizontal direction conversion unit 22 that performs a predetermined conversion process. The horizontal direction conversion unit 22 performs processing such as affine transformation on the supplied image signal.

  The image signal processed by the horizontal direction conversion unit 22 is stored in the line buffer 26 by the FIFO (First In First Out) method. The line buffer 26 is provided with regions [1] to [n] in the same number (n) as the number of pixels in one line constituting the horizontal data line. The image signal output by the horizontal direction conversion unit 22 is stored in the area [n] of the line buffer 26. The image signal stored in the area [n] of the line buffer 26 is the area [1] in the order of the areas [n−1], [n−2],... As the subsequent image signal is stored in the line buffer 26. Move up. Thus, the image signal for one line is stored in the line buffer 26. The image signal is extracted from the area [1]. The image signal output from the horizontal direction conversion unit 22 and the image signal extracted from the area [1] of the line buffer 26 are supplied to multipliers 31a and 32b and multiplied by coefficients A and B, which will be described later. The image signals multiplied by the coefficients A and B are added by an adder 32 and supplied to line buffers 27 and 28 described later.

  Further, a vertical line counter 23 for counting the number of data lines in the vertical direction is provided. The vertical line counter 23 counts the number of vertical lines scanned by the laser beam from the upper end of the screen. The output of the vertical direction line counter 23 is supplied to the horizontal direction pixel counter 24, and the position of the horizontal direction pixels scanned by the laser beam is counted.

  In the present embodiment, the scanning lines for scanning odd frames or even frames are configured to adjust the luminance with reference to two data lines adjacent to the scanning lines. In order to adjust the luminance, a coefficient for obtaining an appropriate luminance corresponding to the scanning position from the number of vertical lines counted by the vertical direction line counter 23 and the number of horizontal pixels counted by the horizontal pixel counter. A and B are stored in the A / B coefficient table 25. The A / B coefficient table 25 supplies the coefficients A and B to the multipliers 31a and 32b.

  When the reciprocating scanning is performed in the horizontal direction, a scanning line is drawn to the lower right or the lower left. In this example, two lines of line buffers 27 and 28 are prepared in order to change the arrangement of pixels according to the scanning direction of the laser beam. The line buffer 27 stores an image signal for outputting the scanning line to the lower right, and the line buffer 28 stores the image signal for outputting the scanning line to the lower left. The output unit 29 that outputs the image signal to the light source 2 moves the output pointer 29a that designates the area in which the image signal is stored for each of the line buffers 27 and 28, and reads the image signal. At this time, the horizontal pixel counter 24 moves the horizontal pointers 30a and 30b with respect to the line buffers 27 and 28, respectively, and counts the positions of the pixels in the horizontal direction scanned by the laser beam. The output pointer 29a is switched by the line buffer switching unit 29b. The line buffers 27 and 28 to be read are switched according to the direction in which the laser beam scans.

  Next, an example of scanning lines drawn on the screen 4 will be described with reference to FIGS. The image signal supply apparatus 1 of the present example generates odd-numbered frame scan lines and even-numbered frame scan lines using image signals generated from two adjacent data lines. FIG. 4 shows scan lines for even frames with respect to the relationship between data lines and scan lines. A horizontal solid line represents a data line, and a plurality of points represent pixels generated on an even frame scan line. The pixel group p1 that forms the scanning line that descends to the left is generated based on the image signals of the data lines d1 and d2.

  Next, an example of scanning lines drawn on the screen 4 will be described with reference to FIG. FIG. 5A shows an example of scan lines in odd frames. FIG. 5B shows an example of even-line scan lines.

  In FIG. 5A, which is a scan line of an odd frame, the waveform of the alternate long and short dash line is shown as the scan line s1. The scanning line s1 draws a sine waveform having amplitudes at both left and right sides of the screen 4. The scanning line s1 starts scanning from the scanning start position c1 of the scanning line s1 at the upper left corner of the screen 4, and repeats a sine waveform that descends to the right end and descends to the left end.

  In the horizontal data lines d1 and d2 indicated by broken lines, there are pixels constituting the image. Here, it is assumed that the pixel G1 exists in the data line d1 and the pixel G2 exists in the data line d2. Assuming this, the pixels actually displayed are placed on the scanning line s1 at the horizontal position corresponding to the pixel G2. In this example, a pixel on the scanning line s1 is a pixel a1. The pixel a1 is a pixel calculated based on the pixel G2 of the data line d2. However, since the pixel a1 is on the sine wave scanning line s1, the pixel a1 is located at a position shifted from the position of the pixel G2.

  In FIG. 5B, which is a scanning line for even frames, the solid line waveform is shown as scanning line s2. The scanning line s2 is delayed by a half cycle with respect to the scanning line s1 of the one-dot chain line. The scanning starts from the scanning start position c2 of the scanning line s2 at the upper right corner of the screen 4, and the sine waveform descending to the left end and descending to the right end is repeated.

  On the horizontal data lines d1 and d2 indicated by broken lines, there are pixels constituting the image. Further, it is assumed that the pixel G1 exists on the data line d1 and the pixel G2 exists on the data line d2. Assuming this, the pixel actually displayed is placed on the scanning line s2 at the horizontal position corresponding to the pixel G2. In this example, a pixel on the scanning line s2 is a pixel a1 ′. The pixel a1 ′ is a pixel calculated based on the pixel G2 of the data line d2. However, since the pixel a1 ′ is on the sine wave scanning line s2, the pixel a1 ′ is located at a position shifted from the position of the pixel G2.

  The image signal supply device 1 of this example sets the luminance of the pixels displayed by the scanning lines based on the pixel data of a plurality of adjacent data lines. Therefore, in FIG. 5A, values corresponding to the distance from the pixel G1 and the pixel G2 with respect to the pixel a1 are stored in the A / B coefficient table 25 as coefficients A and B, respectively. Here, the coefficients A and B correspond to the internal division ratio for obtaining the luminance of the pixel on the scanning line s1 from the data line d1 and the data line d2. Similarly, in FIG. 5B, values corresponding to the distance from the pixel G1 and the pixel G2 for the pixel a1 ′ are stored in the A / B coefficient table 25 as coefficients B and A, respectively.

  In FIG. 5A, the pixel a1 is in the vicinity of the data line d1. However, in FIG. 5B, the pixel a1 ′ is in the vicinity of the data line d2. Here, it is assumed that after the odd-numbered frame is scanned by the scanning line s1, the even-numbered frame is scanned by the scanning line s2. At this time, if the image signal is not processed, the pixel appears to have moved from the pixel a1 to the position of the pixel a1 ′ even though the same pixel of the same image is displayed, and thus flickering occurs. Furthermore, since the pixel a1 is located in the vicinity of the data line d1, flickering becomes conspicuous if the luminance is different from that of the pixel G1.

  In order to prevent such flickering, the luminance of the pixels a1 and a1 ′ displayed on the scanning lines s1 and s2 is adjusted.

  Next, an example of image signal conversion processing performed using the image signal supply device 1 of this example will be described.

  First, when the scan mirror 18 is driven to resonate, the horizontal deflection amount is given by a sine wave. For this reason, when a scanning line is drawn with a constant number of clocks, the interval between pixels is not constant. For this reason, the horizontal direction conversion part 22 calculates each position of the horizontal direction of a pixel.

The calculation process of the horizontal direction conversion unit 22 is performed as follows. Assuming that the number of pixel clocks during one cycle is L, the horizontal position of the X clock with respect to the left side of the screen 4 is
L / 2 (1-cos (2πX / L))
Given in. here,
an integer part of m = {L / 2 (1-cos (2πX / L))},
n = {L / 2 (1-cos (2πX / L))}. Then the pixel position is
OUT (X) = (1−n) × IN (m) + n × IN (m + 1)
Is calculated as Here, IN () represents an input image signal. OUT () represents an output image signal.

  When the laser beam is reciprocated, the number of clocks is constant, so that the pixel density increases near the left and right ends of the screen 4. For this reason, the brightness near the left and right ends is higher than that near the center of the screen 4. In order to eliminate such luminance unevenness, the horizontal direction conversion unit 22 multiplies the luminance of each pixel by sin (2πX / L). In this way, the brightness of each pixel can be made uniform, and the unevenness of brightness can be eliminated.

  Next, an example of processing for placing pixels on the scan line s1 in the odd-numbered frame will be described. Of the horizontal lines, the image signal extracted from the area [1] of the line buffer 26 is multiplied by the multiplier 31b by the coefficient A extracted from the A / B coefficient table 25. On the other hand, for the image signal after one line corresponding to the area [1] of the line buffer 26 (supplied from the horizontal conversion unit 22), the coefficient B extracted from the A / B coefficient table 25 is multiplied by the multiplier 31a. Multiplied by. The coefficients A and B stored in the A / B coefficient table 25 are switched according to the direction in which the scanning line is drawn. Then, the image signal extracted from the line buffer 26 multiplied by the coefficient and the image signal after one line are added. The added image signal is stored in order from the area [n] in the line buffers 27 and 28 provided with the areas [1] to [n] for one line.

  The output unit 29 that reads the image signal moves the output pointer 29a for each area of the line buffer 27 or each area of the line buffer 28, and reads and outputs the image signal stored in each area.

  When drawing the scanning line s1 downward, the output pointer 29a is moved to the area [n] of the line buffer 27 and the image signal is read out. Then, the image signal is read out in the order of region [n−1],..., Region [2], region [1] of the line buffer 27, and the scanning line s1 is drawn.

  On the other hand, when drawing the scanning line s1 downward, the line buffer switching unit 29b is operated to switch the output pointer 29a so as to read the line buffer 28. Then, the output pointer 29a is moved to the area [1] of the line buffer 28, and the image signal is read out. Then, the image signal is read out in the order of region [2],..., Region [n−1], region [n] of the line buffer 28, and the scanning line s1 is drawn.

  Next, an example of processing for placing pixels on the scanning line s2 of the even frame will be described. Of the horizontal lines, the image signal extracted from the area [1] of the line buffer 26 is multiplied by the coefficient B extracted from the A / B coefficient table 25. On the other hand, the image signal corresponding to the area [1] after one line is multiplied by the coefficient A extracted from the A / B coefficient table 25. Then, the image signal extracted from the line buffer 26 multiplied by the coefficient and the image signal after one line are added. The added image signal is stored in order from the area [n] in the line buffers 27 and 28 provided with the areas [1] to [n] for one line.

  When drawing the scanning line s2, the order is reverse to that of the scanning line s1. First, when drawing the scanning line s2 downward, the output pointer 29a is moved to the area [1] of the line buffer 28, and the image signal is read out. Then, the image signal is read out in the order of region [2],..., Region [n−1], region [n] of the line buffer 28, and the scanning line s2 is drawn.

  On the other hand, when drawing the scanning line s2 downward, the line buffer switching unit 29b is operated to switch the output pointer 29a so as to read the line buffer 27. Then, the output pointer 29a is moved to the area [n] of the line buffer 27, and the image signal is read out. Further, the image signal is read out in the order of region [n−1],..., Region [2], region [1] of the line buffer 27, and the scanning line s2 is drawn.

  When drawing the scanning lines s1 and s2, the image signals corresponding to the next data line are stored in the order in which the data is read from the line buffers 27 and 28. In this way, the scanning line can be drawn in the left-right direction without any delay.

  In order to invert the phase of the scanning line, a detection unit (not shown) for detecting the frequency of the voltage supplied to the scan mirror 18 is provided to notify the image signal supply apparatus 1 of the detection result. The detected frequency oscillation of the scan mirror 18 and the image signal read from the output unit 29 are made to correspond to each other, and the laser beam is emitted from the light source 2 so that the phase is inverted and the scan lines of the odd and even frames are drawn. Can do.

  In the first embodiment described above, the output of the image signal is delayed by one line by sandwiching the line buffer 26 in order to reciprocately scan the scanning lines. Then, the image signal stored in the line buffer 26 and the image signal supplied from the horizontal direction conversion unit 22 are multiplied by the coefficient read from the A / B coefficient table 25 and added, so that the lower right and the left A downward scanning line was formed. Since the luminance of the scanning line is adjusted based on the luminance information of the data line adjacent to the scanning line, it is possible to suppress the flicker of the image projected on the screen.

  Further, after scanning an odd frame image, the phase of the odd frame is inverted to scan the even frame. By doing so, since scanning is performed with two frames whose phases are different by 180 degrees, there is an effect that the resolution of both the left and right ends can be improved. In addition, there is an effect that an image can be displayed brightly.

  Next, a second embodiment of the present invention will be described with reference to FIGS. The present embodiment is also an example applied to a projector apparatus that displays an image by scanning a laser beam emitted from a laser light source on a screen. Since the entire configuration example of the projector device and the two-axis MEMS scanner has the same configuration as that of the first embodiment already described, detailed description thereof will be omitted.

  An example of the internal configuration of the image signal supply device 40 that generates the image signal of this example will be described with reference to FIG. The image signal supply device 40 of this example includes a line buffer for two lines, and generates pixels on the scanning line from three data lines adjacent to the scanning line. An image signal source image signal (not shown) is supplied to the image signal supply device 40. The image signal supply device 40 includes an input unit 41 as an image signal input unit, and supplies the input image signal to a horizontal direction conversion unit 42 that performs a predetermined conversion process. The horizontal direction conversion unit 42 performs processing such as affine transformation on the supplied image signal.

  The image signal processed by the horizontal direction conversion unit 42 is stored in the line buffer 46a by the FIFO (First In First Out) method. The line buffer 46a and the line buffer 46b described later are provided with regions [1] to [n] in the same number (n) as the number of pixels in one line constituting the horizontal data line. The image signal output from the horizontal direction conversion unit 42 is stored in the area [n] of the line buffer 46a. The image signal stored in the region [n] moves to the region [1] in the order of the region [n−1], [n−2],... As the subsequent image signal is stored in the line buffer 46a. Thus, the image signal for one line is temporarily stored in the line buffer 46a. The image signal is extracted from the area [1] of the line buffer 46a.

  The image signal supply device 40 of this example includes a line buffer 46b for storing data lines for two lines. Similarly to the line buffer 46a, the line buffer 46b is also provided with regions [1] to [n] in the same number (n) as the number of pixels of one line constituting the horizontal data line. The image signal extracted from the line buffer 46a is stored in the area [n] of the line buffer 46b. The image signal stored in the region [n] moves to the region [1] in the order of the region [n−1], [n−2],... As the subsequent image signal is stored in the line buffer 46b. Thus, the image signal for one line is temporarily stored in the line buffer 46b. The image signal is extracted from the area [1] of the line buffer 46b.

  The image signal output from the horizontal direction conversion unit 42 and the image signal extracted from the area [1] of the line buffer 46a are multiplied by coefficients A and B, which will be described later, stored in the multipliers 51a and 51b. The image signals multiplied by the coefficients A and B are added by an adder 52 and supplied to line buffers 47 and 48 described later.

  Similarly, coefficient B, which will be described later, stored in multipliers 51b and 51c for the image signal extracted from area [1] of line buffer 46a and the image signal extracted from area [1] of line buffer 46b. C is multiplied. The image signals multiplied by the coefficients B and C are added by an adder 52 and supplied to line buffers 47 and 48 described later.

  A vertical line counter 43 that counts the number of data lines in the vertical direction counts the number of vertical lines scanned by the laser beam from the upper end of the screen. On the other hand, the horizontal pixel counter 44 that counts the number of pixels in the horizontal direction counts the positions of the horizontal pixels scanned by the laser beam.

  The luminance of the scanning line that scans the odd or even frame is adjusted with reference to two data lines adjacent to the scanning line. In order to adjust the luminance, an appropriate luminance corresponding to the scanning position is obtained from the number of vertical lines counted by the vertical direction line counter 43 and the number of horizontal pixels counted by the horizontal pixel counter 44. The coefficients A, B, and C are stored in the A / B / C coefficient table 45. The A / B / C coefficient table 45 supplies the coefficients A and B to the multipliers 51a and 52b, and supplies the coefficients B and C to the multipliers 52b and 52c.

  Next, an example of scanning lines drawn on the screen 4 will be described with reference to FIGS. The image signal supply device 40 of this example generates an odd-numbered frame scan line and an even-numbered frame scan line using image signals generated from three adjacent data lines. FIG. 7 shows scan lines for even frames with respect to the relationship between data lines and scan lines. A horizontal solid line represents a data line, and a plurality of points represent pixels generated on an even frame scan line. The pixel group p12 of the second half of the left-down scanning line and the first half of the right-down scanning line are generated based on the image signals of the data lines d12 and d13. The pixel group p11 of the second half of the right-down scanning line and the first half of the left-down scanning line are generated based on the image signals of the data lines d11 and d12.

  When the laser beam is reciprocally scanned, a scanning line is drawn to the lower right or the lower left. Then, two lines of buffer buffers 47 and 48 are used to change the arrangement of pixels according to the direction of the scanning line. The line buffer 47 stores an image signal to be output to the lower right of the pixel groups p11 and p12. The line buffer 48 stores an image signal to be output to the lower left of the pixel groups p11 and p12. The output unit 49 that outputs the image signal to the light source reads the image signal for each of the line buffers 47 and 48 by using an output pointer 49a that designates an area in which the image signal is stored. The output pointer 49a is switched by the line buffer switching unit 49b, and the line buffers 47 and 48 to be read are switched.

  Here, an example of image signal conversion processing will be described. Here, the line buffer 46a stores an image signal corresponding to the data line d12, and the line buffer 46b stores an image signal corresponding to the data line d11. In the horizontal direction conversion unit 42, the image signal corresponding to the data line d13 is converted.

  First, when calculating an image signal corresponding to the pixel group p11, the image signal read from the line buffer 46a is multiplied by a coefficient B, and the image signal read from the line buffer 46b is multiplied by a coefficient C. Then, the image signal supplied from the horizontal direction conversion unit 42 is multiplied by a coefficient A. The image signals multiplied by the coefficients A, B, and C are added and stored in the line buffer 47 or 48. At this time, the value of the coefficient A is 0.

  When calculating the image signal corresponding to the pixel group p12, the image signal read from the line buffer 46a is multiplied by the coefficient B, and the image signal read from the line buffer 46b is multiplied by the coefficient C. Then, the image signal supplied from the horizontal direction conversion unit 42 is multiplied by a coefficient A. The image signals multiplied by the coefficients A, B, and C are added and stored in the line buffer 47 or 48. At this time, the value of the coefficient C is 0.

  In this example, the example in which the image signals of the pixel groups p11 and p12 in FIG. 5 are stored in the line buffers 47 and 48 has been described, but the processing for storing the subsequent image signals is similarly performed.

  Here, an example of the scanning lines drawn on the screen will be described with reference to FIG. Both the alternate long and short dash line and the solid line represent scanning lines, and draw a sine waveform having amplitudes at the left and right ends of the screen. The waveform of the alternate long and short dash line indicates the scan line s11 of the odd-numbered frame. The scanning line s11 repeats a sine waveform that starts scanning from the scanning start position c11 of the scanning line s11 at the upper left corner of the screen, descends to the right end, and returns to the left end. On the other hand, the solid waveform indicates the scanning line s12 of the even frame. The scanning line s12 is delayed by a half cycle with respect to the waveform of the alternate long and short dash line, starts scanning from the scanning start position c12 of the scanning line s12 in the upper right corner of the screen, returns to the left end, and returns to the right end. repeat.

  When drawing from the lower right half of the scanning line s11 to the lower left half, the output pointer 49a is moved to the area [n] of the line buffer 48 and the image signal is read out. Then, the image signal is read out in the order of region [n−1],..., Region [2], region [1] of the line buffer 48, and the scanning line s11 is drawn.

  On the other hand, when drawing from the lower left half of the scanning line s11 to the lower right half, the line buffer switching unit 49b is operated to switch the output pointer 49a to the line buffer 47. Then, the output pointer 49a is moved to the area [n] of the line buffer 47, and the image signal is read out. Then, the image signal is read out in the order of region [n−1],..., Region [2], region [1] of the line buffer 47, and the scanning line s11 is drawn.

  When drawing from the lower left half of the scanning line s12 to the lower right half, the output pointer 49a is moved to the area [n] of the line buffer 48 and the image signal is read out. Then, the image signal is read out in the order of region [n−1],..., Region [2], region [1] of the line buffer 48, and the scanning line s12 is drawn.

  On the other hand, when drawing from the lower right half of the scanning line s12 to the lower left half, the line buffer switching unit 49b is operated to switch the output pointer 49a to the line buffer 47. Then, the output pointer 49a is moved to the area [n] of the line buffer 47, and the image signal is read out. Further, the image signal is read out in the order of region [n−1],..., Region [2], region [1] of the line buffer 47, and the scanning line s12 is drawn.

  Then, the image signal corresponding to the next data line is stored in the line buffer in the order in which the data is read from the line buffer. In this way, the scanning line can be drawn in the left-right direction without any delay.

  In order to invert the phase of the scanning line, a detection unit (not shown) for detecting the frequency of the voltage supplied to the scan mirror is provided to notify the image signal supply device 40 of the detection result. By correlating the detected frequency oscillation of the scan mirror with the image signal read from the output unit 49 and emitting a laser beam from the light source, the scanning line can be drawn with the phase reversed.

  In the second embodiment described above, in order to reciprocately scan the scanning lines, the output of the image signal is delayed by a maximum of two lines across the line buffers 46a and 46b. Then, the image signal stored in the line buffers 46a and 46b and the image signal supplied from the horizontal direction conversion unit 42 are multiplied by the coefficient read from the A / B / C coefficient table 45, and added to the right. I tried to draw down and left-down scanning lines. In addition, after scanning an odd-numbered frame image, the phase of the odd-numbered frame is delayed by a half period to scan an even-numbered frame image. By doing so, since the frame is composed of two frames whose phases are different by 180 degrees, there is an effect that the resolution of both the left and right ends can be improved and the image can be displayed brightly.

  According to the first and second embodiments described above, the horizontal position (phase) at which scanning is started is changed for each frame in order to suppress a decrease in resolution near the left and right ends of the screen 4. By doing so, there is an effect that the resolution near the left and right ends of the screen 4 can be increased.

  In addition, when changing the horizontal position (phase) at which scanning is started for each frame, luminance information and the like are proportional to the distance from each line based on adjacent two or three line image signals. Apportioned to generate and display signals for each pixel. By doing so, there is an effect that it is possible to avoid a problem that the position of the pixel to be displayed is shifted depending on the frame and the display becomes unnatural.

  Further, by performing the horizontal direction conversion process performed in the horizontal direction conversion processing unit, most of the amplitude that the scan mirror resonates and scans can be used. For this reason, when compared with a projector apparatus using a light source having the same brightness, there is an effect that a brighter display can be achieved.

  In the first and second embodiments described above, horizontal scanning and vertical scanning are performed using a biaxial MEMS scanner, but the same operation can be performed even if the scanning direction is changed. For example, even if sine wave vibration is performed in the vertical direction and sawtooth vibration is performed in the horizontal direction, functions and effects similar to those of the first and second embodiments described above can be obtained.

  In the first and second embodiments described above, the present invention is applied to the projector apparatus, and the vertical scanning and the horizontal scanning are performed using the biaxial MEMS scanner. However, the scanning is performed using the display apparatus of other forms. May be performed. It goes without saying that the same functions and effects as those of the first and second embodiments described above can be obtained even when scanning is performed using another type of apparatus.

  In the first and second embodiments described above, the luminance is adjusted using the coefficients stored in the coefficient table. However, the hue, saturation, etc. may also be adjusted. . By doing in this way, there exists an effect that an image can be displayed more smoothly.

  In the first and second embodiments described above, the image signal to be placed on the scanning line is generated based on the adjacent two-line or three-line image signal. However, an image using more data lines than three lines is used. A signal may be generated. By doing so, there is an effect that a higher definition image can be obtained.

  Further, one frame may be divided into two fields composed of the same image, and the phase of scanning in the odd field and the even field may be reversed. In this way, it is possible to scan different positions between the even-line scan lines and the odd-field scan lines. Therefore, the screen is scanned more densely than in the case where scanning is performed in the same phase in each field, and the resolution of the display image can be improved. In particular, there is an effect that it is possible to suppress resolution degradation at the left and right ends of the screen. In addition, there is an effect that an image with less flicker can be obtained.

It is the external block diagram which showed the example of the projector apparatus in the 1st Embodiment of this invention. It is the external block diagram which showed the example of the biaxial MEMS scanner in the 1st Embodiment of this invention. It is an internal block diagram which showed the example of the image signal supply apparatus in the 1st Embodiment of this invention. It is explanatory drawing which showed the example of the data line and scanning line in the 1st Embodiment of this invention. It is explanatory drawing which showed the example of the scanning line of the odd-numbered frame in the 1st Embodiment of this invention, and an even-numbered frame. It is an internal block diagram which showed the example of the image signal supply apparatus in the 2nd Embodiment of this invention. It is explanatory drawing which showed the example of the data line and scanning line in the 2nd Embodiment of this invention. It is explanatory drawing which showed the example of the scanning line of the odd-numbered frame in the 2nd Embodiment of this invention, and an even-numbered frame. It is explanatory drawing which showed the example of the conventional scanning line.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image signal supply apparatus, 2 ... Light source, 3 ... Projection optical system, 4 ... Screen, 5 ... Sine wave, 6 ... Saw tooth, 7 ... Main axis scanning direction, 8 ... Sub-axis scanning direction, 10 ... 2-axis MEMS scanner, 11a, 11b ... Magnets for secondary shaft electromagnetic drive, 12a, 12b ... Secondary shaft torsion bar, 13 ... Coil for secondary shaft electromagnetic drive, 14a, 14b ... Secondary shaft electrode, 15a, 15b ... Main shaft electrode, 16a, 16b ... Main shaft torsion Bars, 17a, 17b ... rotation side electrodes, 18 ... scan mirror, 19 ... inner frame part, 20 ... outer frame part, 21 ... input part, 22 ... horizontal conversion part, 23 ... vertical line counter, 24 ... horizontal Direction pixel counter, 25 ... A / B coefficient table, 26, 27, 28 ... line buffer, 29 ... output unit, 29a ... output pointer, 29b ... line buffer switching unit, 30a, 30b ... Flat pointer, 31a, 31b ... multiplier, 32 ... adder, 41 ... input unit, 42 ... horizontal direction conversion unit, 43 ... vertical direction line counter, 44 ... horizontal direction pixel counter, 45 ... A / B / C coefficient table 46a, 46b, 47, 48 ... line buffer, 49 ... output unit, 49a ... output pointer, 49b ... line buffer switching unit, 50a, 50b ... horizontal pointer, 51a, 51b, 51c ... multiplier, 52 ... adder, 100: Projector device

Claims (8)

An image signal supply unit for supplying an image signal composed of odd frames and even frames;
A light source unit that modulates and emits a laser beam according to an image signal supplied from the image signal supply unit;
The laser beam emitted from the light source unit is two-dimensionally scanned by horizontal and vertical vibrations of the image, and the scanning trajectory of the odd frame image signal and the scanning trajectory of the even frame image signal are inverted. And a scanning unit that sets the drawing start position of each frame to a different position.
And a projection optical unit that projects the laser beam scanned by the scanning unit. The display device according to claim 1,
The image signal of each scanning line scanned by the scanning unit is generated by adding signals of two or more horizontal lines of the image signal input to the image signal supply unit at a predetermined ratio. Characteristic display device. The display device according to claim 2, wherein
An image signal generated by adding two or more horizontal line signals of the image signal at a predetermined ratio is an image signal on a scanning locus corresponding to a sine wave in the scanning unit. Characteristic display device. A laser beam is modulated and emitted by an image signal composed of odd and even frames,
A display method in which the emitted laser beam is two-dimensionally scanned with a horizontal vibration and a vertical vibration of an image, and the scanned laser beam is projected and displayed.
The scanning trajectory of the odd-numbered frame image signal and the scanning trajectory of the even-numbered frame image signal at the time of performing the scanning are set to an inverted phase, and the drawing start position of each frame is set to a different position. And display method. An image signal supply unit that supplies an image signal in which one frame is constituted by an odd field and an even field;
A light source unit that modulates and emits a laser beam according to an image signal supplied from the image signal supply unit;
The laser beam emitted from the light source unit is two-dimensionally scanned by horizontal and vertical vibrations of the image, and the scanning trajectory of the odd field image signal and the scanning trajectory of the even field image signal are inverted. And a scanning unit that sets the drawing start position of each field to a different position.
And a projection optical unit that projects the laser beam scanned by the scanning unit. The display device according to claim 5, wherein
The image signal of each scanning line scanned by the scanning unit is generated by adding signals of two or more horizontal lines of the image signal input to the image signal supply unit at a predetermined ratio. Characteristic display device. The display device according to claim 6, wherein
An image signal generated by adding two or more horizontal line signals of the image signal at a predetermined ratio is an image signal on a scanning locus corresponding to a sine wave in the scanning unit. Characteristic display device. A laser beam is modulated and emitted by an image signal in which one frame is composed of an odd field and an even field,
A display method in which the emitted laser beam is two-dimensionally scanned with a horizontal vibration and a vertical vibration of an image, and the scanned laser beam is projected and displayed.
The scanning trajectory of the image signal of the odd field and the scanning trajectory of the image signal of the even field at the time of performing the scanning are set to the inverted phase, and the drawing start position of each field is set to a different position. And display method.

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