JP4654832B2 - Image display device and control method of image display device - Google Patents

Description

  The present invention relates to an image display device and a method for controlling the image display device, and more particularly to a technique of an image display device that displays an image by scanning a laser beam modulated according to an image signal.

In recent years, a laser projector that displays an image by scanning a laser beam has been proposed as an image display device that displays an image. Laser light is characterized by high monochromaticity and directivity. For this reason, the laser projector has an advantage that an image with good color reproducibility can be obtained. When an image is displayed by scanning with laser light, it is required to modulate the laser light at a high frequency as the image is made high resolution. For example, when a full high-definition image of 1920 × 1080 pixels is displayed by scanning a single laser beam, if one frame period is 1/60 seconds, the modulation of the laser beam is performed at a very high frequency of about 130 MHz. There is a need to do. Further, when using pulse width modulation (hereinafter referred to as “PWM”) for changing the pulse width for turning on the laser light in accordance with the image signal, when n-bit gradation expression is performed, A modulation frequency of 2 ⁿ times is required.

  When an image is displayed by scanning with laser light, it is necessary to increase the output of the laser light as the screen for displaying the image becomes larger. For example, in order to display an image with a luminance of 500 nits on a 60-inch screen, an output of 5 to 10 watts is required. When such a high output is provided by a single laser beam, a very large and expensive laser light source is required. Thus, since it is extremely difficult to display an image by scanning a single laser beam, a technique for displaying an image by scanning a plurality of laser beams has been proposed (for example, Patent Documents). 1). When scanning a plurality of laser beams, the modulation frequency can be reduced by assigning the scanning region to each laser beam. Also, the output per laser beam can be reduced in inverse proportion to the number of laser beams.

JP 2003-172900 A

  When an image is displayed using a plurality of laser beams, the image may be uneven due to differences in the brightness of the laser beams due to factors such as individual differences in laser light sources. According to the technique proposed in Patent Document 1, a plurality of laser beams are overlapped and scanned, and brightness differences of the plurality of laser beams are integrated and recognized, thereby leveling the difference in the brightness of the laser beams. Is possible. However, when the brightness of a plurality of laser beams changes in the same tendency due to factors such as temperature changes, uneven brightness occurs even if the brightness of the plurality of laser beams is leveled. When the brightness of a plurality of laser beams changes with the same tendency, the brightness of the plurality of laser beams is adjusted by using Auto Power Control (hereinafter referred to as “APC”). It is possible. Conventionally, APC is performed by measuring light supplied from a light source and feeding back measurement results so that the brightness is substantially constant. In this case, since it is difficult to sufficiently cope with a large change or abrupt change in the amount of laser light caused by the occurrence of electrical noise, image display is performed with insufficient brightness correction. Could be continued. In particular, when performing high-speed scanning with laser light, even if a delay in correcting brightness unevenness occurs on the order of microseconds, display is performed at a gradation different from the image signal in hundreds to thousands of pixels. Therefore, there is a problem that noticeable brightness unevenness is likely to occur. The present invention has been made in view of the above-described problems. An image display apparatus capable of sufficiently reducing brightness unevenness using a plurality of light beams and capable of displaying a high-quality image, and control of the image display apparatus. It aims to provide a method.

  In order to solve the above-described problems and achieve the object, according to the present invention, an image display device that displays an image by scanning a plurality of light beams, the light source unit that supplies the light beams, and the light source And a scanning unit that scans the light beam from the first part in the irradiated region in a first direction and a second direction substantially orthogonal to the first direction, and the light source unit sequentially outputs the plurality of light beams. Driven to express gradation by scanning, and corrects the light quantity of another beam light different from the one light beam according to the light quantity of at least one of the light beams. An image display device that is driven can be provided.

  It is assumed that the light amount of a certain light beam among a plurality of light beams has decreased. In this case, in order to compensate for such a decrease in the amount of light, correction is performed to increase the amount of other light beams that are scanned after the light beam whose light amount has decreased. In this way, it is possible to reduce the occurrence of uneven brightness due to a change in the amount of light for each beam. In the present invention, even when the brightness of a plurality of light beams changes with the same tendency, the brightness unevenness can be reduced by correcting the light amount of the light beams. In addition, even when there is a significant change or abrupt change in the light amount of the beam light, it is sufficient to correct the light amount when another beam light scans after the beam light whose light amount has decreased. It is also possible to reduce brightness unevenness due to a delay in correction. As a result, the brightness unevenness can be sufficiently reduced by using a plurality of light beams, and an image display device capable of displaying a high-quality image can be obtained.

  Further, according to a preferred aspect of the present invention, it is desirable that the light source unit is further driven so as to correct the amount of light of one beam. By correcting the light amount of the single beam light whose light amount has changed by feedback, the brightness unevenness can be further reduced.

  Further, according to a preferred aspect of the present invention, it is desirable that the light source unit is driven so as to correct the light amount of the beam light to be scanned next to one of the other light beams. Thereby, uneven brightness can be reduced with a simple configuration.

  According to a preferred aspect of the present invention, the light source unit is driven so as to correct the light quantity of the beam light scanned after the beam light scanned after the one beam light among the other light beams. desirable. By correcting the light amount of the light beam scanned after the light beam next to the one light beam, it is possible to gain time until the correction is performed. Thereby, correction of the light quantity of beam light can be performed reliably. Further, an expensive circuit or the like for performing high-speed light amount control is not necessary, and the manufacturing cost can be reduced.

  According to a preferred aspect of the present invention, the scanning unit is driven such that the frequency at which the beam light is scanned in the first direction is higher than the frequency at which the beam light is scanned in the second direction. It is desirable that the unit is configured so that the spots of the light beams of the same color are juxtaposed in the second direction in the irradiated region. The light beams of the same color are light beams having wavelength regions that are substantially the same or approximate to each other. By supplying a plurality of light beams of the same color so that the spots are arranged in parallel, gradation can be expressed by sequentially scanning the plurality of light beams. Further, the output can be shared by a plurality of light beams.

  Further, as a preferred aspect of the present invention, the light source unit is preferably configured so that the spots are arranged in parallel at intervals set in units of the width of the scanning line that scans the beam light in the first direction. For example, assume that a plurality of light beams are scanned for each row. By arranging the spots in parallel at an interval set with the scanning line width as a unit, it is possible to gain time until the next beam light scans after one beam light scans. This makes it possible to reliably correct the amount of light at the time when the next light beam scans. Further, an expensive circuit or the like for performing high-speed light amount control is not necessary, and the manufacturing cost can be reduced.

  Moreover, as a preferable aspect of the present invention, a first light source unit for scanning a plurality of light beams in the first region of the irradiated region and a plurality of beams in the second region of the irradiated region. A second light source unit for scanning light, a part of the first region and a part of the second region overlap each other, and the first light source unit and the second light source unit In the portion where the first and second regions overlap, the beam has a light amount distribution such that the light amount of the light beam from the second light source unit increases as the light amount of the light beam from the first light source unit decreases. It is desirable to supply light. By sharing the scanning area with the light beam from the first light source unit and the light beam from the second light source unit, the modulation frequency for modulating the light beam can be reduced. Further, the light amount distribution is such that the light amount of the light beam from the second light source unit increases as the light amount of the light beam from the first light source unit decreases at the portion where the first region and the second region overlap. As a result, the joint between the first region and the second region can be made inconspicuous. Thereby, a high quality image can be displayed with a low modulation frequency.

  As a preferred aspect of the present invention, it is desirable that the light source unit is driven so as to express the maximum gradation with a light amount smaller than the maximum light amount that can be supplied for a plurality of light beams. By setting the light amount smaller than the maximum light amount that can be supplied as the maximum gradation, it is possible to secure a large increase amount of the light amount for correction. For example, even if the supply of one light beam is stopped due to some trouble, it is possible to continue image display with another light beam by securing a large increase in the amount of light for correction. It becomes possible.

  Furthermore, according to the present invention, there is provided a control method for an image display device that displays an image by scanning a beam of light, the beam light supplying step for supplying a plurality of light beams, and the beam light in an irradiated region. A first step, a scanning step of scanning in a second direction substantially orthogonal to the first direction, a light amount detection step of detecting a light amount of at least one of the plurality of light beams, and a light amount detection step A method for controlling an image display apparatus, comprising: a light amount correction step of correcting a light amount of another beam light different from the one light beam according to the detected light amount of the one light beam. be able to. When a change in the light amount of one light beam is detected in the light amount detection step, the light amount of the other light beam is corrected in the light amount correction step. In this way, it is possible to reduce the occurrence of uneven brightness due to a change in the amount of light for each beam. According to the present invention, even when the brightness of a plurality of light beams changes with the same tendency, the brightness unevenness can be reduced by correcting the light amount of the light beams. In addition, even when there is a significant change or abrupt change in the light amount of the beam light, it is sufficient to correct the light amount when another beam light scans after the beam light whose light amount has decreased. It is also possible to reduce brightness unevenness due to a delay in correction. Thereby, brightness unevenness can be sufficiently reduced using a plurality of light beams, and a high-quality image can be displayed.

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

  FIG. 1 shows a schematic configuration of an image display apparatus 100 according to Embodiment 1 of the present invention. The image display device 100 is a so-called rear projector that supplies laser light to one surface of the screen 110 and observes an image by observing light emitted from the other surface of the screen 110. The image display apparatus 100 displays an image by scanning laser light, which is a plurality of light beams, in the X direction that is the horizontal direction and the Y direction that is the vertical direction.

  FIG. 2 shows a schematic configuration of the laser apparatus 101. The laser device 101 includes an R light source 121 </ b> R that supplies red laser light (hereinafter referred to as “R light”) that is beam light, and green laser light (hereinafter referred to as “G light”) that is a beam light. Light source unit 121G for supplying G light and B light source unit 121B for supplying blue laser light (hereinafter referred to as “B light”) which is beam light.

  Each color light source unit 121R, 121G, 121B supplies five laser lights of the same color modulated according to the image signal. As the modulation according to the image signal, either amplitude modulation or pulse width modulation may be used. The laser device 101 is provided with two dichroic mirrors 124 and 125. The dichroic mirror 124 transmits R light and reflects G light. The dichroic mirror 125 transmits R light and G light and reflects B light. The R light from the R light source unit 121 </ b> R passes through the dichroic mirrors 124 and 125 and is then emitted from the laser device 101.

  The G light from the G light source 121G is reflected by the dichroic mirror 124, whereby the optical path is bent by approximately 90 degrees. The G light reflected by the dichroic mirror 124 passes through the dichroic mirror 125 and is then emitted from the laser device 101. The B light from the B light source 121B is reflected by the dichroic mirror 125, so that the optical path is bent by approximately 90 degrees. The B light reflected by the dichroic mirror 125 is emitted from the laser device 101. In this way, the laser device 101 supplies R light, G light, and B light modulated according to the image signal.

  Returning to FIG. 1, the laser light from the laser device 101 enters the scanning unit 200 after passing through the illumination optical system 102. The light from the scanning unit 200 enters the reflection unit 105 after passing through the projection optical system 103. The illumination optical system 102 and the projection optical system 103 image the laser light from the laser device 101 on the screen 110. The reflection unit 105 reflects the laser light from the scanning unit 200 toward the screen 110. The housing 107 seals the space inside the housing 107.

  The screen 110 is provided on a predetermined surface of the housing 107. The screen 110 is a transmissive screen that transmits laser light modulated in accordance with an image signal. The light from the reflection unit 105 enters from the surface of the screen 110 on the inner side of the housing 107 and then exits from the surface on the viewer side. An observer observes the image by observing light emitted from the screen 110.

  FIG. 3 shows a schematic configuration of the scanning unit 200. The scanning unit 200 has a so-called double gimbal structure having a reflection mirror 202 and an outer frame portion 204 provided around the reflection mirror 202. The outer frame portion 204 is connected to a fixed portion (not shown) by a torsion spring 206 that is a rotating shaft. The outer frame portion 204 rotates around the torsion spring 206 using the twist of the torsion spring 206 and the restoration to the original state. The reflection mirror 202 is connected to the outer frame portion 204 by a torsion spring 207 that is a rotation axis substantially orthogonal to the torsion spring 206. The reflection mirror 202 reflects the laser light from the laser device 101. The reflection mirror 202 can be configured by forming a highly reflective member, for example, a metal thin film such as aluminum or silver.

  The reflection mirror 202 is displaced so that the laser beam is scanned in the Y direction (see FIG. 1) on the screen 110 when the outer frame portion 204 rotates about the torsion spring 206. The reflection mirror 202 rotates about the torsion spring 207 using the twist of the torsion spring 207 and the restoration to the original state. The reflection mirror 202 is displaced so as to scan the laser beam reflected by the reflection mirror 202 in the X direction by rotating about the torsion spring 207. Thus, the scanning unit 200 repeatedly scans the laser light from the laser device 101 in the X direction and the Y direction.

  FIG. 4 illustrates a configuration for driving the scanning unit 200. Assuming that the side on which the reflection mirror 202 reflects the laser light is the front side, the first electrodes 301 and 302 are spaces on the back side of the outer frame portion 204 and are provided at substantially symmetrical positions with respect to the torsion spring 206. Yes. When a voltage is applied to the first electrodes 301 and 302, a predetermined force corresponding to the potential difference, for example, an electrostatic force, is generated between the first electrodes 301 and 302 and the outer frame portion 204. The outer frame portion 204 rotates about the torsion spring 206 by alternately applying a voltage to the first electrodes 301 and 302.

  Specifically, the torsion spring 207 includes a first torsion spring 307 and a second torsion spring 308. A mirror-side electrode 305 is provided between the first torsion spring 307 and the second torsion spring 308. A second electrode 306 is provided in the space behind the mirror side electrode 305. When a voltage is applied to the second electrode 306, a predetermined force according to the potential difference, for example, an electrostatic force, is generated between the second electrode 306 and the mirror side electrode 305. When a voltage having the same phase is applied to any of the second electrodes 306, the reflection mirror 202 rotates about the torsion spring 207. The scanning unit 200 rotates the reflection mirror 202 in this way, thereby scanning the laser light in the two-dimensional direction. The scanning unit 200 can be created by, for example, MEMS (Micro Electro Mechanical Systems) technology.

  For example, during one frame period of the image, the scanning unit 200 reflects the laser beam so as to reciprocate the laser beam a plurality of times in the X direction that is the main scanning direction while scanning the laser beam once in the Y direction that is the sub scanning direction. 202 is displaced. Assuming that the X direction is the first direction and the Y direction is the second direction substantially orthogonal to the first direction, the scanning unit 200 has a frequency at which the laser beam is scanned in the first direction. Driven to be higher than the frequency of scanning light. In order to scan the laser beam in the X direction at high speed, it is desirable that the scanning unit 200 be configured to resonate the reflecting mirror 202 around the torsion spring 207. By causing the reflection mirror 202 to resonate, the amount of displacement of the reflection mirror 202 can be increased. By increasing the displacement amount of the reflection mirror 202, the scanning unit 200 can efficiently scan the laser beam with less energy. The reflection mirror 202 may be driven by an operation other than the resonance operation.

  The scanning unit 200 is not limited to the configuration driven by the electrostatic force corresponding to the potential difference. For example, the structure driven using the expansion-contraction force or electromagnetic force of a piezoelectric element may be sufficient. The scanning unit 200 may include a reflection mirror that scans the laser light in the X direction and a reflection mirror that scans the laser light in the Y direction. Furthermore, the scanning unit 200 is not limited to a configuration using a galvanometer mirror, and may use a polygon mirror that rotates a rotating body having a plurality of mirror pieces.

  FIG. 5 illustrates the optical path of the laser light from the R light source unit 121R. Here, the configuration for supplying the laser light from the R light source unit 121R among the light source units for each color light will be described as a representative example, and illustrations of components unnecessary for the description are omitted. The R light source unit 121 </ b> R includes five laser elements 501. The laser element 501 is, for example, an edge emitting semiconductor laser. Each laser element 501 supplies laser light modulated independently.

  The illumination optical system 102 provided between the R light source unit 121 </ b> R and the scanning unit 200 can be configured by combining a convex lens 502 and a concave lens 503. The illumination optical system 102 adjusts the interval between the five laser beams by the convergence effect of the convex lens 502 and the diffusion effect of the concave lens 503. The projection optical system 103 between the scanning unit 200 and the screen 110 projects the laser light from the R light source unit 121 </ b> R onto the screen 110. By using the illumination optical system 102 and the projection optical system 103, a high-definition image can be displayed on the screen 110. The five laser elements 501 are not limited to a configuration in which all the laser elements 501 are integrally arranged, and may be arranged apart from each other according to a desired interval of the laser light.

  A detector (not shown) that detects the amount of laser light supplied from the laser element 501 is provided inside each laser element 501. The amount of laser light supplied from each laser element 501 can be monitored by the detector. The detector is not limited to one that detects the amount of laser light inside the laser element 501, but may be one that detects laser light outside the laser element 501.

  FIG. 6 illustrates the pixels P formed in the irradiated area of the screen 110. In the image display apparatus 100, n pixels P in the Y direction and m pixels P in the X direction are formed by the laser light modulated according to the image signal. Here, it is assumed that an arbitrary pixel P is represented as Pij, with the coordinate in the X direction as i (= 1 to m) and the coordinate in the Y direction as j (= 1 to n) with the upper left portion of the irradiated region as a reference.

  7 and 8 are diagrams for explaining scanning of laser light by the image display apparatus 100. FIG. The image display apparatus 100 causes the spots SP1 to SP5 to be arranged in parallel at the same pitch as the pixel P in the Y direction, and scans five rows of laser light for each row. The pitch of the pixels P in the Y direction is, in other words, the pitch of the scanning line that scans the laser beam in the X direction. If one side of the pixel P and the diameter of the spot SP are substantially the same, the interval between the laser beams is adjusted so that the spots SP are arranged in parallel without any gap.

  In FIG. 7, in the first scan SC1 in the X direction, the spot SP1 at the lower end of the spots SP1 to SP5 is moved from the left to the right on the pixels P in the first row (i = 1). Next, in the second scan SC2, the spot SP1 is moved on the second row (i = 2) of the pixels P, and the spot SP2 is moved on the first row of pixels P from right to left. After repeating such scanning, in the (n + 3) -th scan SC (n + 3) shown in FIG. 8, the spot SP4 is on the pixel P in the nth row (i = n) and the spot SP5 is in the (n−1) th row. The pixel P on (i = n−1) is moved from left to right. In the (n + 4) -th scan SC (n + 4), the spot SP5 is moved from the right to the left on the pixel P in the n-th row (i = n).

  In this way, the image display apparatus 100 sequentially scans all the pixels P with five laser beams while scanning the laser beams once in the Y direction. The light source unit is driven to express gradation by sequentially scanning five laser beams. Here, consider a case where 128 gradations are displayed in an arbitrary pixel Pij when the image display apparatus 100 expresses gradations with 8 bits. The light source unit changes the light amount by 8 bits for each of the five laser beams, and displays the 128 gradations by summing the light amounts of the five laser beams. Assuming that there is no output difference between the laser elements 501 (see FIG. 5) of the light source unit, the five laser beams are modulated to substantially the same amount of light corresponding to 128 gradations at the timing when each scans the pixel Pij. .

For example, it is assumed that the photodetector in the laser element 501 detects that the laser beam forming the spot SP1 has dropped to a light amount corresponding to 120 gradations at the timing of scanning the pixel Pij. In this case, the gradation of the pixel Pij is reduced to 126.4 gradation as calculated below.
(120 + 128 + 128 + 128 + 128) /5=126.4 (gradation)

In order to reduce the brightness change of the pixel Pij, the image display apparatus 100 corrects the light amount of the laser light forming the spot SP2 to a light amount corresponding to, for example, 136 gradations. In this case, even if the laser beam forming the spot SP1 decreases to a light amount corresponding to 120 gradations, the pixel Pij can be displayed with 128 gradations as calculated below.
(120 + 136 + 128 + 128 + 128) / 5 = 128 (gradation)

  As described above, the image display device 100 has a light source unit that corrects the light amount of the other laser light different from the one laser light according to the change in the light amount of one of the five laser lights. Drive. Furthermore, it is assumed that the laser beam forming the spot SP2 cannot be made into a light amount corresponding to 136 gradations, and is corrected to a light amount corresponding to, for example, 134 gradations. In this case, the pixel Pij can be displayed with 128 gradations by further correcting the light quantity of the laser light forming the spot SP3 to the light quantity corresponding to 130 gradations. Thus, it is also possible to correct the amount of laser light over a plurality of stages.

  In the present invention, even when the brightness of a plurality of laser beams changes with the same tendency, the brightness unevenness can be reduced by correcting the light amount of the laser beams. In addition, even when there is a significant change or abrupt change in the amount of laser light, it is sufficient to correct the amount of light at the time when another laser beam scans after the laser light whose amount of light has decreased. It is also possible to reduce brightness unevenness due to a delay in correction. As a result, the uneven brightness can be sufficiently reduced by using a plurality of light beams, and an effect that a high-quality image can be displayed is achieved.

  When scanning a plurality of laser beams, the output per laser beam can be reduced in inverse proportion to the number of laser beams. Therefore, a bright image can be displayed using a small and inexpensive laser element by scanning a plurality of laser beams.

  FIG. 9 shows a block configuration for controlling the image display apparatus 100. The image signal input unit 711 performs characteristic correction and amplification of the image signal input from the input terminal. For example, the image signal input unit 711 converts an analog image signal into a digital light source modulation intensity signal and outputs it. In addition, the image signal input unit 711 may output a digital image signal as a digital light source modulation intensity signal. The synchronization / image separation unit 712 separates the signal from the image signal input unit 711 into an image information signal, a vertical synchronization signal, and a horizontal synchronization signal for each of R light, G light, and B light, and outputs them to the control unit 713. To do. The image processing unit 721 in the control unit 713 divides the image information into information for each frame and outputs the information to the frame memory 714. The frame memory 714 stores the image signal from the image processing unit 721 in units of frames.

  The scanning control unit 723 of the control unit 713 generates a drive signal for driving the scanning unit 200 based on the vertical synchronization signal and the horizontal synchronization signal. The scan driver 715 drives the scanner 200 in response to a drive signal from the controller 713. In the scanning process, with this configuration, the laser beam is scanned in the X direction and the Y direction in the irradiated region. The horizontal angle sensor 716 detects the swing angle of the reflection mirror 202 (see FIG. 3) that scans the laser beam in the X direction on the screen 110. The vertical angle sensor 717 detects the swing angle of the reflection mirror 202 that causes the screen 110 to scan the laser beam in the Y direction. The signal processing unit 718 generates a frame start signal F_Sync from the displacement of the vertical angle sensor 717 and a line start signal L_Sync from the displacement of the horizontal angle sensor 716, and outputs them to the control unit 713.

  The control unit 713 generates a pixel timing clock based on the linear velocity calculated from the frame start signal F_Sync, the line start signal L_Sync, the vertical synchronization signal, and the horizontal synchronization signal. The pixel timing clock is a signal for knowing the timing at which the laser beam passes on each pixel, and is for causing the laser beam modulated in accordance with the image signal to enter an accurate position.

  The R light source driving unit 732R drives the R light source unit 121R based on the light source driving pulse signal from the light source control unit 722. The R light source driving unit 732R controls turning on and off of the five laser beams supplied from the R light source unit 121R according to the light source driving pulse signal. The G light source driving unit 732G also drives the G light source unit 121G in the same manner as the R light source driving unit 732R. Similarly to the R light source driving unit 732R, the B light source driving unit 732B drives the B light source unit 121B. Each color light source unit 121R, 121G, 121B is driven according to a drive signal whose pulse width is controlled according to an image signal. In the beam light supplying step, a plurality of laser beams are supplied with this configuration.

  FIG. 10 illustrates a configuration for correcting the amount of laser light from the R light source unit 121R. The image information signal generated by the image processing unit 721 is input to the five laser elements 501-1 to 501-5 via the R light source driving unit 732R. The detectors 602-1 to 602-5 are provided in the laser elements 501-1 to 501-5, respectively. The first correction unit 603-1 corrects the light amount of the laser light from the second laser element 501-2 based on the detection result by the first detection unit 602-1 that detects the laser light of the first laser element 501-1. To do.

  The second correction unit 603-2 corrects the light amount of the laser light from the third laser element 501-3 according to the detection result by the second detection unit 602-2 that detects the laser light of the second laser element 501-2. To do. The third correction unit 603-3 corrects the light amount of the laser light from the fourth laser element 501-4 according to the detection result by the third detection unit 602-3 that detects the laser light of the third laser element 501-3. To do. The 4th correction | amendment part 603-4 correct | amends the light quantity of the laser beam from the 5th laser element 501-5 according to the detection result by the 4th detection part 602-4 which detects the laser beam of the 4th laser element 501-4. To do.

  With this configuration, the image display apparatus 100 can drive the light source unit so as to correct the light amount of the laser light scanned next to the one laser light in accordance with the change in the light amount of the one laser light. It is possible to simplify the connection of the correction units 603-1 to 603-4 by correcting the light amount of the laser light scanned next to one laser light. Therefore, uneven brightness can be reduced with a simple configuration. In addition, according to the structure of a present Example, the light quantity of another laser beam cannot be correct | amended with respect to the light quantity change of the laser beam from the 5th laser element 501-5 scanned last among five laser beams. . On the other hand, as will be described later, it is possible to reduce the uneven brightness by correcting the amount of light by feedback based on the detection result of the laser beam from the fifth laser element 501-5.

  FIG. 11 illustrates an image display apparatus according to the first modification of the present embodiment. In the image display device 100 described above, the spots SP are arranged in parallel with no gap, whereas the present modification is different in that the spots SP are arranged in parallel at intervals corresponding to the width of one scanning line. The width of one scanning line is the same as the pitch of the pixels P in the Y direction. Only the laser beam forming the spot SP1 reciprocates once in the X direction by the first scan SC1 and the second scan SC2. Next, in the third scan SC3, the spot SP2 is moved from left to right on the pixel P in the first row, and the spot SP1 is moved from left to right on the pixel P in the third row. By repeating this scanning (n + 9) times, all the pixels P are sequentially scanned with five laser beams.

  According to the present modification, it is possible to gain time until scanning with the next laser beam after scanning with one laser beam, as compared with the image display device 100 described above. This makes it possible to reliably correct the amount of light at the time when the next laser beam scans. Further, an expensive circuit or the like for performing high-speed light amount control is not necessary, and the manufacturing cost can be reduced. Note that the interval between the spots SP is not limited to one scanning line, but may be set in units of the width of the scanning line, or may be two or more scanning lines.

  The image display apparatus 100 is not limited to a configuration that supplies five laser beams for each color light, and may be any configuration that supplies a plurality of laser beams for each color light. Moreover, it is not restricted to scanning each color light using the one scanning part 200, For example, it is good also as using a different scanning part for every color light. In this case, the number of laser beams may be varied for each color light. In addition, the light source unit for each color light is not limited to a configuration in which a plurality of laser elements 501 (see FIG. 5) are provided, and may have a configuration in which a plurality of light emitting units such as a surface emitting semiconductor laser is provided. Further, each color light source unit is not limited to a configuration in which the spots are arranged in parallel in the Y direction, but may be configured in such a manner that the spots SP are arranged in an array.

  FIG. 12 illustrates an image display apparatus according to the second modification of the present embodiment, and illustrates a configuration for correcting the amount of laser light from the R light source unit 121R. The present modification is characterized in that the amount of laser light scanned next to one laser beam and the amount of one laser beam are corrected in accordance with the change in the amount of one laser beam. Based on the detection result of the first detection unit 602-1, the first correction unit 603-1, in addition to the amount of laser light from the second laser element 501-2, laser light from the first laser element 501-1. The amount of light is also corrected. Similar to the first correction unit 603-1, the other correction units 603-2 to 603-5 other than the first correction unit 603-1 also adjust the amount of laser light from each laser element 501-2 to 502-5. Make corrections. As described above, the brightness unevenness can be further reduced by correcting the light amount of one laser light whose light amount has changed by feedback.

  FIG. 13 illustrates an image display apparatus according to the third modification of the present embodiment, and illustrates a configuration for correcting the amount of laser light from the R light source unit 121R. The present modification is characterized in that the light quantity of the laser light scanned after the laser light scanned after the one laser light is corrected in accordance with the change in the light quantity of the one laser light. For example, the first correction unit 603-1 is based on the detection result by the first detection unit 602-1, in addition to the second laser element 501-2, through the other correction units 603-2 to 603-4. The amount of laser light from at least one of the third laser element 501-3, the fourth laser element 501-4, and the fifth laser element 501-5 can be corrected. In this case, each laser beam from the third laser element 501-3, the fourth laser element 501-4, and the fifth laser element 501-5 corresponds to a laser beam scanned after the beam light after the one beam light. .

  By correcting the amount of light for the laser beam scanned after the laser beam next to the one laser beam, it is possible to earn time until the correction is performed. Thereby, correction of the light quantity of a laser beam can be performed reliably. Further, an expensive circuit or the like for performing high-speed light amount control is not necessary, and the manufacturing cost can be reduced.

  Further, it is desirable that each color light source unit is driven so as to express the maximum gradation with a light amount smaller than the maximum light amount that can be supplied for a plurality of laser beams. By setting the light amount smaller than the maximum light amount that can be supplied as the maximum gradation, it is possible to secure a large increase amount of the light amount for correction. For example, even if the supply of one laser beam is completely stopped due to some trouble, image display is continued with another laser beam by securing a large increase in the amount of light for correction. It becomes possible.

  FIG. 14 illustrates an image display apparatus according to Embodiment 2 of the present invention. The image display apparatus according to the present embodiment scans the first region with the laser beam from the first R light source unit 121R and the second region with the laser beam from the second R light source unit 1121R. And The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. As shown in FIG. 14, the second R light source unit 1121R has the same configuration as the first R light source unit 121R, and supplies laser light to the screen 110 through the same configuration. The five laser beams from the first R light source unit 121R scan the first region on the plus Y side of the irradiated region. The five laser beams from the second R light source 1121R scan the second region on the minus Y side of the irradiated region. For the G light and B light, two light source units are provided as in the case of R light.

  FIG. 15 describes the first region and the second region in detail. In FIG. 15, the irradiated area AR0 is formed by overlapping a part AR12 on the lower side of the first area AR1 and a part AR22 on the upper side of the second area AR2. The irradiated area AR0 is formed by matching the positions AA and BB of the first area AR1 and the second area AR2.

  Of the first region AR1, the portion AR11 other than the portion AR12 that is overlapped with the second region AR2 performs gradation expression using only the five laser beams from the first R light source unit 121R. For the portion AR12, gradation expression is performed using the five laser beams from the first R light source unit 121R and the five laser beams from the second R light source unit 1121R. In addition, the first R light source 121R is driven so that the amount of light decreases in the portion AR12 as it goes downward, which is the second region AR2.

  Of the second region AR2, the portion AR21 other than the portion AR22 to be overlapped with the first region AR2 performs gradation expression using only the five laser beams from the second R light source unit 1121R. For the portion AR22, gradation expression is performed using the five laser beams from the second R light source unit 1121R and the five laser beams from the first R light source unit 121R. In addition, the second R light source 1121R is driven so that the amount of light decreases in the portion AR22 as it goes upward, which is the first area AR1 side. The first R light source unit 121R and the second R light source unit 1121R have lasers from the second R light source unit 1121R as the amount of laser light from the first R light source unit 121R decreases in the portions AR12 and AR22. Laser light is supplied so as to obtain a light amount distribution that increases the amount of light.

  By dividing the scanning region by the laser light from the first R light source 121R and the laser light from the second R light source 1121R, the modulation frequency for modulating the laser light can be reduced. In addition, the laser light from the second R light source 1121R decreases as the amount of laser light from the first R light source 121R decreases in the portions AR12 and AR21 where the first region AR1 and the second region AR2 overlap. By making the light amount distribution such that the amount of light increases, the joint between the first area AR1 and the second area AR2 can be made inconspicuous. Thereby, a high quality image can be displayed with a low modulation frequency.

  FIG. 16 shows a schematic configuration of an image display apparatus 1700 according to the third embodiment of the present invention. The image display device 1700 is a so-called front projection projector that supplies laser light to a screen 1705 provided on the viewer side and observes an image by observing light reflected by the screen 1705. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. Laser light from the scanning unit 200 passes through the projection optical system 103 and then enters the screen 1705. In the case of this embodiment as well, uneven brightness can be sufficiently reduced by using a plurality of light beams, and a high-quality image can be displayed.

  In the above embodiment, each color light source unit uses a semiconductor laser. However, the present invention is not limited to this as long as it can supply beam-shaped light. For example, each color light source unit may be configured to use a liquid laser or a gas laser in addition to a solid-state light emitting element such as a solid-state laser and a light-emitting diode element (LED).

  As described above, the image display device according to the present invention is suitable for displaying an image using a plurality of light beams.

1 is a diagram illustrating a schematic configuration of an image display apparatus according to Embodiment 1 of the present invention. The figure which shows schematic structure of a laser apparatus. The figure which shows schematic structure of a scanning part. The figure explaining the structure for driving a scanning part. The figure explaining the optical path of the laser beam from the light source part for R light. The figure explaining the pixel formed in the to-be-irradiated area | region of a screen. 6A and 6B illustrate scanning of laser light by an image display device. FIG. 10 is another diagram illustrating scanning of laser light by the image display device. The figure which shows the block structure for controlling an image display apparatus. The figure explaining the structure for correct | amending the light quantity of a laser beam. FIG. 6 is a diagram illustrating an image display device according to a first modification of the first embodiment. FIG. 6 is a diagram illustrating an image display device according to a second modification of the first embodiment. FIG. 6 is a diagram illustrating an image display device according to a third modification of the first embodiment. FIG. 6 is a diagram illustrating an image display device according to a second embodiment of the invention. The figure explaining the 1st field and the 2nd field. FIG. 9 is a diagram illustrating a schematic configuration of an image display device according to a third embodiment of the invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Image display apparatus, 101 Laser apparatus, 102 Illumination optical system, 103 Projection optical system, 105 Reflection part, 107 Housing | casing, 110 Screen, 200 scanning part, 121RR Light source part for 121R G light source part, 121B B Light source section for light, 124, 125 Dichroic mirror, 202 Reflective mirror, 204 Outer frame section, 206 Torsion spring, 207 Torsion spring, 301, 302 First electrode, 305 Mirror side electrode, 306 Second electrode, 307 First Torsion spring, 308 second torsion spring, 501 laser element, 502 convex lens, 503 concave lens, P pixel, SP spot, 711 image signal input unit, 712 synchronization / image separation unit, 713 control unit, 714 frame memory, 715 scanning Drive unit, 716 horizontal angle sensor, 717 vertical angle sensor, 718 signal processing unit, 721 image processing unit, 722 light source control unit, 723 scanning control unit, 732R R light source driving unit, 732G G light source driving unit, 732B B light source driving unit, 501-1 to 501-5 Laser element, 602-1 to 602-5 detection unit, 603-1 to 603-5 correction unit, 1121R R light source unit, AR0 irradiated region, AR1 first region, AR2 second region, 1700 image display Equipment, 1705 screen

Claims (5)

An image display device that displays an image by scanning a plurality of light beams,
A light source unit for supplying the light beam;
A scanning unit that scans the beam light from the light source unit in a first direction in a region to be irradiated and a second direction substantially orthogonal to the first direction;
The scanning unit is driven such that a frequency at which the light beam is scanned in the first direction is higher than a frequency at which the light beam is scanned in the second direction.
The light source unit is
The spot of the light beam of the same color is configured to be juxtaposed in the second direction in the irradiated region,
It is driven so as to express gradation by sequentially scanning a plurality of the light beams, and the light amount of one light beam excluding the light beam that scans the irradiated region last among the plurality of light beams. In response to the change, it is driven to correct the light amount of the beam light to be scanned next to the one light beam ,
Wherein among the plurality of light beams to detect a change of the light amount of the light beam to be scanned last an irradiated region, that you correct the light beam quantity to finally scan the irradiated region based on the detection result A characteristic image display device. The light source unit according to claim 1, characterized in that it is configured to parallel the spot in the intervals set a first width of the scan lines for scanning the light beam in a direction as a unit Image display device. A first light source unit for scanning a plurality of the light beams in a first region of the irradiated region;
A second light source unit for scanning a plurality of the light beams in a second region of the irradiated region,
A portion of the first region and a portion of the second region overlap each other;
The first light source unit and the second light source unit are configured such that the light amount of the beam light from the first light source unit decreases in a portion where the first region and the second region overlap. the image display apparatus according to claim 1 or 2, characterized in that providing the light beam so that the beam light quantity distribution quantity as is much of the light source unit. The light source unit, a plurality of the light beam, according to any one of claims 1 to 3, characterized in that it is driven to represent the maximum gray level by less amount than the maximum amount which can be supplied Image display device. A method for controlling an image display device that displays an image by scanning a beam of light,
A light beam supplying step for supplying a plurality of the light beams;
The frequency at which the beam light is scanned in a first direction and a second direction substantially orthogonal to the first direction in the irradiated region , and the beam light is scanned in the first direction is A scanning step of scanning so as to be higher than a frequency of scanning the light beam in the second direction ;
A light amount detection step of detecting a light quantity of a plurality of the beam light sac Chi one beam,
A beam that scans next to the one light beam in accordance with the light amount of the one beam light, excluding the beam light that scans the irradiated region last among the plurality of light beams detected in the light amount detection step. Next beam light quantity correction process for correcting the light quantity,
In accordance with the light amount of the light beam scanning the irradiation target region is detected in the light amount detection step at the end, seen including a final beam light amount correction step of correcting the light amount of the light beam for scanning the irradiated region at the end ,
The method of controlling an image display device, wherein the light supplying step supplies a plurality of the light beams so that the spots of the light beams of the same color are arranged in the second direction in the irradiated region .

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