JP5191730B2 - Two-dimensional image forming apparatus - Google Patents

Description

  The present invention relates to a two-dimensional image forming apparatus using a coherent light source as a light source. More specifically, the present invention relates to a two-dimensional image forming apparatus having means for reducing speckle noise appearing in a display.

  FIG. 16 shows a schematic configuration of a conventional laser display. The light beams from the RGB three-color laser light sources 101 a to 101 c are expanded by the beam expander 102, and the two-dimensional spatial light modulator 107 is irradiated by the light integrator 103. The optical integrator 103 is a moth-eye lens in which rectangular unit lenses are two-dimensionally arranged, and the light intensity distribution having a substantially Gaussian distribution is substantially uniform on the two-dimensional spatial light modulator 107. The two-dimensional spatial light modulator 107 is irradiated with uniform intensity. A diffusion plate 105 is disposed in front of the two-dimensional spatial light modulator 107 and is rotated in the plane by the diffusion plate swinging portion 112. The lights that have passed through the two-dimensional spatial light modulator 107 are combined by the dichroic prism 110 and projected as a full-color image on the screen 108 by the projection lens 109.

  A feature of such a laser display is that a laser light source with strong monochromaticity is used as the light source. In a projector using a lamp, light having a continuous spectrum of a lamp light source is decomposed into RGB three colors, so that each RGB light also has a continuous spectral distribution and cannot display a pure single color. On the other hand, since the laser display uses a monochromatic light source, the color purity is high and a vivid image can be displayed.

  By the way, in such a display, what is called speckle noise, which is caused by using a laser light source having high coherence as a light source, becomes a problem. Speckle noise is fine uneven noise generated when the scattered light from each part on the screen 108 interferes when the laser light is scattered by the screen 108. In order to suppress the speckle noise, the conventionally proposed laser display has a configuration in which the diffusion plate 105 is swung as described with reference to FIG.

That is, the diffusing plate 105 has a surface polished into a glass shape, and applies random phase modulation to incident light. The parallel beam incident on the diffusion plate 105 becomes divergent light that is randomly diffused within a certain angle. The light that has passed through the diffusion plate 105 generates random speckle noise on the two-dimensional spatial light modulator 107. The speckle noise on the two-dimensional spatial light modulator 107 changes at high speed by swinging the diffuser plate 105 within the plane, and the speckle noise of the image projected on the screen 108 is also high speed. Change. When this is observed with eyes, speckle noise that changes at high speed is time-averaged and recognized as a smooth image without noise.
JP 7-297111 A

  However, the problem in the above configuration is that a part of the light scattered by the diffusion plate 105 becomes a loss. The situation is explained in detail below.

  In order to suppress speckle noise more effectively, the diffusion angle of light at the diffusion plate 105 may be increased. At this time, the incident angle of the light that irradiates the two-dimensional spatial light modulation element 107 increases, and as a result, the incident angle of the light that irradiates the screen 108 to the screen 108 also increases. Since the speckle pattern generated instantaneously depends on the incident angle to the screen 108, more speckle patterns are generated and more effectively averaged by entering at a larger angle.

  When the diffusion angle is increased as described above, the light irradiating the outside of the image frame of the two-dimensional spatial light modulator 107 and the light emitted from the pupil of the projection lens 109 increase, resulting in light loss. By reducing the distance between the two-dimensional spatial light modulation element 107 and the diffusion plate 105, the light irradiating outside the image frame of the two-dimensional spatial light modulation element 107 can be reduced, but on the other hand, the particle pattern of the diffusion plate 105 Is imaged on the screen 108 and becomes noise other than speckle noise. For this reason, the distance between the two-dimensional spatial light modulator 107 and the diffusion plate 105 needs to be set at a constant interval, and light that falls outside the image frame of the two-dimensional spatial light modulator 107 cannot be eliminated.

  On the other hand, if the diffusion angle at the diffusing plate 105 is set to be equal to or smaller than the brightness (F value) of the projection lens 109, light loss due to squeezing at the projection lens 109 can be prevented. The outgoing light intensity distribution shows a Gaussian distribution with respect to the diffusion angle, and as the diffusion angle is increased, the displacement at the projection lens 109 increases.

  Further, in the laser display described above, since the light intensity of the beam is made uniform using the optical integrator 103, a certain optical path length is required for the optical integrator 103, and the length of the optical integrator 103 is increased. Further, since the beam incident on the optical integrator 103 is expanded by the beam expander 102, the beam diameter is also increased, and it is necessary to use a large diameter beam expander 102 and the optical integrator 103. As a result, the beam expander 102 and the optical integrator 103 are increased in size, the optical system is increased, and it is difficult to reduce the size of the laser display.

  An object of the present invention is to provide a two-dimensional image forming apparatus capable of reducing speckle noise, reducing light loss, and further reducing the size of an optical system.

  A two-dimensional image forming apparatus according to one aspect of the present invention includes at least one laser light source, beam deflecting means for changing a traveling direction of a light beam emitted from the laser light source, and light emitted from the beam deflecting means. A driving means for driving the beam deflecting means to change the traveling direction of the beam with time, a rod integrator for guiding the light beam deflected by the beam deflecting means to the exit end while internally reflecting, and from the rod integrator A first projection optical system that projects the emitted light beam, a two-dimensional spatial light modulator that modulates the light beam emitted from the first projection optical system, and the two-dimensional spatial light modulator And a second projection optical system that projects light onto a predetermined surface.

  In this two-dimensional image forming apparatus, speckle noise can be reduced, light loss can be reduced, and the optical system can be downsized.

  Hereinafter, a two-dimensional image forming apparatus according to each embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a two-dimensional image forming apparatus according to a first embodiment of the present invention. The two-dimensional image forming apparatus shown in FIG. 1 includes a laser light source 1, a prism array 2, a drive unit 3, a rod integrator 4, a projection optical system 5, a field lens 6, a two-dimensional spatial light modulation element 7, and a projection lens 8.

  The light beam emitted from the laser light source 1 that is a coherent light source passes through the prism array 2 and enters the rod integrator 4. The light beam that has repeatedly undergone internal reflection in the rod integrator 4 and reaches the emission end is projected by the projection optical system 5 onto the transmission type two-dimensional spatial light modulator 7 via the field lens 6. The two-dimensional spatial light modulator 7 is composed of a liquid crystal shutter or the like, and is emitted from the projection optical system 5 by controlling the opening / closing operation of each shutter according to image data output from a signal processing circuit (not shown). The beam is modulated in accordance with the image to be displayed and guided to the projection lens 8. The projection lens 8 projects the light emitted from the two-dimensional spatial light modulator 7 onto a screen (not shown).

  Since the light beam projected onto the two-dimensional spatial light modulator 7 by the projection optical system 5 is a substantially divergent beam as shown in FIG. 1, the field lens 6 converts the substantially divergent beam into a convergent beam, The light that has passed through the two-dimensional spatial light modulator 7 is efficiently incident on the projection lens 8.

  FIG. 2 is a schematic perspective view for mainly explaining the configuration of the prism array shown in FIG. As shown in FIG. 2, the prism array 2 is formed of a disk in which minute prisms are two-dimensionally arranged, for example, a minute unit prism 2 a arranged on the circumference, and is constituted by a motor or the like. The light beam rotated by the driving unit 3 is continuously deflected by different unit prisms 2a. Each unit prism 2a has a surface directed in a different direction, and the light beam is deflected in a different direction by the different unit prism 2a.

  As described above, the light beam passes through a large number of unit prisms 2a per unit time by the rotation of the prism array 2 and is deflected in various directions. Therefore, the beam position changes at high speed on the output end face of the rod integrator 4. The average light irradiation power per time is uniform within the output end face. In order to further improve the uniformity, the surface of each unit prism 2a is formed into a concave lens shape, the deflected light beam becomes a slightly divergent beam, and the light beam at the output end face of the rod integrator 4 has a certain size or more. You can do it.

  At this time, the incident angle of the light beam that irradiates the two-dimensional spatial light modulation element 7 changes from moment to moment, and as a result, the incident angle of the light beam that irradiates the screen changes to the screen. Be suppressed.

  The point of the optical system of the present embodiment is that the prism array 2 is used for deflecting the light beam, so that the deflection angle of the light beam can be designed accurately. For example, when the magnification of the projection optical system 5 is 2 and the brightness of the projection lens 8 is 2.5, if the F value of light emitted from the rod integrator 4 is set to 1.25 or less, the light beam All pass through the inside of the pupil of the projection lens 8 and an optical system free from light loss due to squeezing is realized.

  Here, the rod integrator 4 is a rectangular parallelepiped optical prism, and since the tilt angle of the light is preserved when the light propagates from the incident end to the exit end due to internal reflection, the tilt of the light beam incident on the rod integrator 4 is preserved. The deflection angle in the prism array 2 may be designed so that the angle is equal to or smaller than the angle corresponding to the F value of 1.25.

  Also, if the distance between the rod integrator 4 and the prism array 2 is sufficiently close, the beam position shift at the incident end face of the rod integrator 4 due to the deflection at the unit prism 2 a should be smaller than the size of the incident end face of the rod integrator 4. All the light beams deflected by the prism array 2 enter the rod integrator 4 and irradiate the two-dimensional spatial light modulator 7. For this reason, there is no loss of light caused by irradiating the outside of the image frame of the two-dimensional spatial light modulator 7 as in the conventional example, and an optical system with very little light loss is realized.

  As described above, in the present embodiment, light that is lost at the pupil of the projection lens 8 or light that irradiates the outside of the image frame of the two-dimensional spatial light modulator 7 is not generated. A small optical system can be realized.

  In the present embodiment, the light beam emitted from the laser light source 1 is not expanded, and the light rod intensity distribution is made constant by using the small rod integrator 4. It is not necessary to use an integrator, the optical system can be miniaturized, and the two-dimensional image forming apparatus can be miniaturized.

(Second Embodiment)
FIG. 3 is a schematic configuration diagram of a two-dimensional image forming apparatus according to the second embodiment of the present invention. A difference between the two-dimensional image forming apparatus shown in FIG. 3 and the two-dimensional image forming apparatus shown in FIG. 1 is that a polarizing beam splitter 9 is added, and a transmissive two-dimensional spatial light modulator 7 is a reflective two-dimensional image forming apparatus. It is changed to the three-dimensional spatial light modulation element 7a, and the projection lens 8 is arranged on the upper part of the polarization beam splitter 9, and the other points are the same as the two-dimensional image forming apparatus shown in FIG. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  The reflection type two-dimensional spatial light modulator 7a is composed of, for example, a two-dimensional spatial light modulator called a so-called LCOS (Liquid Crystal On Silicon) device in which a ferroelectric liquid crystal is arranged on a silicon substrate. In the LCOS two-dimensional spatial light modulator, optical switches are arranged two-dimensionally, and the polarization direction of the reflected light is rotated by an input signal. Therefore, of the incident light reflected by the polarizing beam splitter 9, the light incident on the optical switch in the ON state is reflected with its polarization direction rotated and incident on the projection lens 8 through the polarizing beam splitter 9. To do.

  In this optical system, when a method of preventing speckle noise by applying a diffuser plate in the immediate vicinity of the reflective two-dimensional spatial light modulation element 7a as in the conventional example is applied, a rectangular rectangle in FIG. A diffusion plate will be arranged at the represented position. If the diffuser plate is disposed between the reflection type two-dimensional spatial light modulation element 7a and the projection lens 8, the image projected on the screen will be blurred. Therefore, the reflection type two-dimensional spatial light modulation element This is because the diffusion plate cannot be arranged in the optical path through which the reflected light from 7a passes.

  For this reason, the polarizing beam splitter 9 exists between the diffuser plate and the reflective two-dimensional spatial light modulator 7a, and the optical path becomes long. Therefore, most of the light diffused by the diffuser plate is a reflective two-dimensional light beam. It deviates from the image frame of the spatial light modulator 7a. As described above, when the reflective two-dimensional spatial light modulator 7a and the diffusion plate are used in combination, the loss of light is particularly large. On the other hand, in this embodiment, in addition to the effects of the first embodiment, it is not necessary to place a diffusion plate in front of the reflective two-dimensional spatial light modulator 7a, so that a reduction in the amount of light can be prevented. The present invention is particularly effective when a reflective two-dimensional spatial light modulator is used.

(Third embodiment)
FIG. 4 is a schematic configuration diagram of a two-dimensional image forming apparatus according to a third embodiment of the present invention, and FIG. 5 is a schematic perspective view for mainly explaining the configuration of the lenticular lens shown in FIG. is there. In the present embodiment, between the laser light source 1 and the rod integrator 4, two lenticular lenses 10a and 10b rotated by two drive units 3a and 3b are arranged to deflect the light beam. Since the other points are the same as those of the two-dimensional image forming apparatus shown in FIG. 1, the same parts are denoted by the same reference numerals and detailed description thereof is omitted.

  The lenticular lenses 10a and 10b used in the present embodiment are formed by forming a corrugated smooth concavo-convex shape on a disc-shaped substrate on an annular region, and the direction of the concavo-convex shape is Concave and convex shapes are arranged so as to face the radial direction of the disk substrate. Therefore, the lenticular lenses 10a and 10b have a smooth uneven shape with a corrugated cross section, and deflect the incident light beam in a direction perpendicular to the uneven shape.

  The lenticular lenses 10a and 10b are respectively rotated by driving units 3a and 3b including motors and the like in the plane with the center of the disk substrate as the center of rotation. Each time the incident light beam crosses the concavo-convex shape of the lenticular lenses 10a, 10b, the light beam is repeatedly deflected in a direction perpendicular to the concavo-convex shape. At this time, using two lenticular lenses 10a and 10b, one lenticular lens 10a deflects incident light in the horizontal direction, and the other lenticular lens 10b deflects incident light in the vertical direction. 10b is arranged as shown. The depth and period of the concavo-convex shape of each of the lenticular lenses 10 a and 10 b are designed so that the tilt angle does not cause the projection lens 8 to be distorted.

  The feature of the two-dimensional image forming apparatus of the present embodiment is that there is no loss due to light scattering because the surfaces of the lenticular lenses 10a and 10b are composed of continuous surfaces and there are no discontinuous points. For example, in the prism array 2 used in the first embodiment, the surface shape becomes discontinuous at the boundary line where the prism and the prism are adjacent to each other, and the light beam is slightly emitted when irradiating the discontinuous line. Light is scattered and lost. In contrast, the lenticular lenses 10a and 10b have a smooth surface shape and no light is scattered by the boundary line, so that an optical system with little loss is realized.

  Another feature of the two-dimensional image forming apparatus of the present embodiment is that the polarization direction of light passing through the lenticular lenses 10a and 10b does not change. For example, when a liquid crystal two-dimensional spatial light modulator is used as the two-dimensional spatial light modulator 7, the light beam passes through the polarization separation element before and after entering the two-dimensional spatial light modulator 7.

  For example, in the configuration of FIG. 3, a polarizing beam splitter 9 is installed adjacent to the reflective two-dimensional spatial light modulator 7a. Only the polarization component in one direction is reflected by the polarization beam splitter 9 and enters the reflection type two-dimensional spatial light modulation element 7a, and the polarization direction changes according to the input signal. The light whose polarization direction has changed is transmitted through the polarization beam splitter 9 and projected from the projection lens 8 onto the screen. Here, when the light incident on the polarization beam splitter 9 from the rod integrator 4 is not linearly polarized light and includes an unnecessary polarization component, the unnecessary polarization component passes through the polarization beam splitter 9 as shown by a dotted line in FIG. Thus, the light does not enter the reflective two-dimensional spatial light modulator 7a, resulting in light loss.

  Further, even when the transmission type two-dimensional spatial light modulator 7 is used as shown in FIG. 4, when the liquid crystal two-dimensional spatial light modulator is used, the incident side of the liquid crystal two-dimensional spatial light modulator and Since a polarizer (not shown) is arranged on the output side, the unnecessary polarization component is absorbed by the incident-side polarizer, and the unnecessary polarization component is generated in the same manner as in the case of using the reflective liquid crystal two-dimensional spatial light modulator 7a. Loss of light. On the other hand, the light from the laser light source 1 is, for example, horizontal linearly polarized light, and the tilt directions of the surfaces of the two lenticular lenses 10a and 10b are the vertical direction and the horizontal direction. When the beam is deflected by 10b, the polarization direction does not change, and linearly polarized light is incident on the two-dimensional spatial light modulator 7, so that an optical system without loss is realized. In the optical system of the conventional example shown in FIG. 16, the polarization direction of the light that has passed through the diffusion plate 105 is slightly disturbed and an unnecessary polarization component is generated, resulting in light loss.

(Fourth embodiment)
FIG. 6 is a schematic configuration diagram of a two-dimensional image forming apparatus according to a fourth embodiment of the present invention, and FIG. 7 is a diagram showing the arrangement of the concavo-convex shape of the lenticular lens in the two-dimensional image forming apparatus shown in FIG. It is. The back surface shown in FIG. 7 shows a state viewed from the front surface of the lenticular lens 10c, that is, the rod integrator 4 side.

In the present embodiment, the lenticular lens 10c has a corrugated smooth uneven shape on the annular region on the front surface (the surface on the rod integrator 4 side) and the rear surface (the surface on the laser light source 1 side) of the disk-shaped substrate. In this way, two lenticular lenses are formed, and their optical axis directions are orthogonal to each other as shown in FIG. In addition, the direction of the concavo-convex shape on the front surface and the back surface of the lenticular lens 10c is inclined by 45 degrees with respect to the radial direction of the lenticular lens 10c (the broken line direction shown in FIG. 7). direction 45 degrees inclined in the clockwise direction of the back surface of the uneven shape is disposed 45 degrees inclination) to counterclockwise. The lenticular lens 10c is rotated by a drive unit 3c configured by a motor or the like in a plane with the center of the disk-shaped substrate as the rotation center (rotation axis RA). Since the other points are the same as those of the two-dimensional image forming apparatus shown in FIGS. 4 and 5, the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  In such a configuration, the light beam is deflected in the horizontal direction by the lenticular lens on the front surface of the lenticular lens 10c and deflected in the vertical direction by the lenticular lens on the back surface. As a result, the light emitted from the lenticular lens 10c is two-dimensional. Therefore, the emission direction is deflected.

  With the above configuration, in the two-dimensional image forming apparatus of the present embodiment, since the lenticular lens 10c is configured by a single substrate, the number of components can be reduced and the rotation axis RA that rotates the lenticular lens 10c. Therefore, the drive unit 3c, which is a rotation mechanism, can be simplified.

Further, in the present embodiment, the direction connecting the rotation axis RA of the lenticular lens 10c and the point BI where the light beam on the lenticular lens 10c is incident (broken line direction shown in FIG. 6) is relative to the rod integrator 4. Arranged in the 45 degree direction. Further, the incident light beam is arranged so that the deflection direction thereof is linearly polarized light in the horizontal direction or the vertical direction. With this configuration, without polarization direction changes of the deflected light beam by the lenticular lens 10c, no unnecessary polarized light component incident on the two-dimensional spatial light modulating device 7, a small optical system with loss is realized The

(Fifth embodiment)
FIG. 8 is a schematic configuration diagram of a two-dimensional image forming apparatus according to the fifth embodiment of the present invention. In this embodiment, a normal rotationally symmetric lens 11 is used in place of the lenticular lens, and the other points are the same as those of the two-dimensional image forming apparatus shown in FIG. Therefore, detailed description is omitted.

  When the rotationally symmetric lens 11 is used, unlike the case where a lenticular lens is used, it is necessary to swing the lens 11 in a two-dimensional direction (the arrow direction in the figure), and a stepping motor or the like is used as a drive source. The lens 11 is swung in a two-dimensional direction by a driving unit 3d including an XY stage. Also in this case, the light transmitted through the lens 11 is deflected in the direction in which the lens 11 is moved, and the angle of the light incident on the two-dimensional spatial light modulator 7 is changed in the same manner as when the lenticular lens is rotated. To suppress the speckle noise. Further, the two-dimensional image forming apparatus according to the present embodiment can use the lens 11 that is smaller than the lenticular lens, and has an effect that a small optical system can be realized.

(Sixth embodiment)
FIG. 9 is a schematic configuration diagram of a two-dimensional image forming apparatus according to the sixth embodiment of the present invention. In this embodiment, a diffusing plate 12 is used instead of a lenticular lens, and the other points are the same as those of the two-dimensional image forming apparatus shown in FIG. Description is omitted.

  The light beam from the laser light source 1 irradiates a diffusion plate 12 provided near the incident end of the rod integrator 4. The diffusion plate 12 has a random surface shape and has an action of diffusing transmitted light. The light diffused in various angular directions repeats total reflection in the rod integrator 4 to reach the exit end of the rod integrator 4 and irradiates the two-dimensional spatial light modulator 7 through the projection optical system 5. Also in this optical system, as in the optical system using a beam deflecting means such as a lenticular lens, the light that irradiates the two-dimensional spatial light modulation element 7 is incident at various angles and has the effect of suppressing speckle noise. have. That is, by oscillating the diffusion plate 12 by the drive unit 3e, the speckle noise pattern generated is changed at high speed, and the speckle noise patterns that change at high speed when observed are averaged over time. Recognized as a noise-free image.

  Further, by making the diffusing surface of the diffusing plate 12 approach the incident end of the rod integrator 4, the light emitted from the diffusing plate 12 can be incident on the rod integrator 4 without loss, and an optical system with little optical loss can be realized. . Further, the light diffusion angle can be controlled by controlling the surface shape such as the depth of the unevenness of the diffusion plate 12 and the size of the graininess. In this way, an incident angle of light incident on the two-dimensional spatial light modulation element 7 is controlled, and an optical system with little light loss due to squeezing at the projection lens 8 is realized.

  In this embodiment, since the diffusion plate 12 is used as the beam deflecting means, the swing speed of the diffusion plate 12 can be reduced. Usually, the size of the lenticular lens is about 0.5 to 5 millimeters, whereas the diffusion plate 12 has a granular surface shape of 5 to 50 micrometers. For this reason, the oscillating speed of the diffusion plate 12 required to change the speckle noise sufficiently fast so that the speckle noise generated on the screen is time-averaged is the oscillation speed of the lenticular lens. It may be about 1/10 of the speed. According to experiments, when the diffusion plate 12 was swung at 5 mm per second, a noise-free image in which speckle noise was sufficiently suppressed was observed.

  The diffusion plate used in the present embodiment is not particularly limited to the above example, and a pseudo-random diffusion plate 12a as shown in FIG. 10 may be used. In this case, the effect of further reducing light loss. There is. While the diffuser plate is usually produced by randomly roughing the surface of a transparent substrate such as glass or resin, the pseudo-random diffuser plate 12a shown in FIG. 10 is formed by forming lattice-like irregularities on the surface of the transparent substrate. Produced. The surface of the pseudo-random diffuser 12a is divided into two-dimensional lattice cells CE, and the depth of the unevenness is set so that the phase of light passing through each cell CE changes randomly. The maximum depth may be λ / (n−1).

The advantage of using the pseudo-random diffusion plate 12a of FIG. 10 is that the diffusion angle of light passing through the pseudo-random diffusion plate 12a can be strictly controlled by the size of the cell CE. That is, assuming that the cell pitch of the lattice cell CE is d and the angle is θ,
I (θ) = {sin (α) / α} ² (α = θ × d / (π · λ))
The light is diffused with an intensity distribution as follows. For example, in order to fabricate a diffuser plate with a full angle at half maximum of the diffusion angle of 10 degrees, the cell pitch d with respect to the wavelength λ can be obtained by setting I (θ) = 1/2 in the above equation. When light sources having wavelengths of blue, green, and red are set to λ = 0.473, 0.532, and 0.640 micrometers, respectively, the cell pitch d is 2.4, 2.7, 3,. What is necessary is just to produce by 2 micrometers.

  Since the surface shape of a normal diffuser plate is random, (1) the local diffusion angle differs depending on the location and the light utilization efficiency decreases, (2) the transmittance varies depending on the location, and the intensity distribution unevenness in the image And (3) it is difficult to stably produce the diffusion angle to be constant. In addition, with a normal diffuser plate, there is a problem that the deflection direction is disturbed when the scattering angle is increased. These problems can be solved with the pseudo-random diffuser 12a shown in FIG.

  Further, the pseudo-random diffuser plate 12a shown in FIG. 10 can be produced by forming a concavo-convex pattern on a glass plate by a photolithography method and an etching method used in a normal semiconductor process. At this time, if the phase shift is selected as 0, π / 2, π, 3π / 2 as shown in FIG. 10, it is easily fabricated by two etchings corresponding to the phase shift of π / 2, π. be able to.

(Seventh embodiment)
FIG. 11 is a schematic configuration diagram of a two-dimensional image forming apparatus according to the seventh embodiment of the present invention. In each of the above-described embodiments, the configuration using the device using light refraction such as the prism array 2, the lenticular lenses 10a to 10c, the lens 11, and the diffusion plate 12 has been described as the beam deflecting unit. It is also possible to perform the same operation using a movable mirror comprising a mirror that becomes and a drive unit that is a drive means for driving the mirror. In this embodiment, a MEMS (Micro Electro Mechanical Systems) mirror 13 is used as an example of a movable mirror instead of a lenticular lens, and the other points are the same as those of the two-dimensional image forming apparatus shown in FIG. The same parts are denoted by the same reference numerals, and detailed description thereof is omitted.

  The two-dimensional MEMS mirror 13 is a movable mirror made of a silicon crystal having a thickness of about 10 microns, and a central mirror portion 13a is held at a position floating from the bottom substrate by an etching technique. The central mirror part 13a is connected to the mirror holding part 13b by a beam from the up and down direction. Further, the mirror holding portion 13b is supported by a beam from the left-right direction.

Below the bottom board of the central mirror portion 13a is split electrodes (not shown) to the left and right is formed by a voltage to mark pressure to between the central mirror portion 13a and a bottom electrode on the substrate, the The central mirror portion 13a is inclined in the left-right direction around the direction in which the beam is twisted by the electrostatic force, that is, the vertical rotation axis. The bottom substrate corresponding to the mirror holder 13b, by vertically split electrodes (not shown) is formed on, to mark pressurizing a voltage between the mirror holding portion 13b and the bottom electrode on the substrate, the static electricity Due to the force, the mirror holding portion 13b is inclined in the vertical direction about the direction in which the beam is twisted, that is, the horizontal rotation axis. By controlling the inclination in both axial directions at the same time, the inclination of the central mirror portion 13a can be freely set in the two-dimensional direction.

  Since the size of the central mirror portion 13a is as small as about 1 mm square and its rotational moment is also small, the primary resonance frequency in the torsional direction can be increased by designing the thickness and width of the beam portion, and the horizontal rotation axis A high primary resonance frequency can be easily obtained at the center. When the central mirror portion 13a is 1 mm square, the beam width is 50 microns, and the beam length is 200 microns, the primary resonance frequency is about 15 kHz and the resonance frequency in the Y direction is about 4 kHz. The beam could be deflected.

  With the above configuration, in the present embodiment, the deflection angle of the light beam can be accurately controlled by the MEMS mirror 13, so that the light emitted from the pupil of the projection lens 8 and the outside of the image frame of the two-dimensional spatial light modulation element 7 can be obtained. Therefore, an optical system with a very small loss of light can be realized.

(Eighth embodiment)
FIG. 12 is a schematic configuration diagram of a two-dimensional image forming apparatus according to an eighth embodiment of the present invention. In the above embodiment, the MEMS mirror 13 is used as the movable mirror, but the same operation can be performed using a polygon mirror or a galvanometer mirror. In this embodiment, a polygon mirror 14 and a galvanometer mirror 15 are used as an example of a movable mirror instead of a lenticular lens, and the other points are the same as those of the two-dimensional image forming apparatus shown in FIG. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  The polygon mirror 14 reflects the light beam emitted from the laser light source 1 and deflects it in the X direction, and the galvano mirror 15 further reflects the light beam reflected by the polygon mirror 14 and reflects it in the Y direction (perpendicular to the X direction). 2 direction beam deflection.

  With the above-described configuration, the deflection angle of the light beam can be accurately controlled by the polygon mirror 14 and the galvanometer mirror 15 in the present embodiment as well, so that the light emitted from the pupil of the projection lens 8 and the two-dimensional spatial light modulator Since no light that is lost when irradiated outside the image frame 7 is generated, an optical system with very little light loss can be realized.

(Ninth embodiment)
FIG. 13 is a schematic configuration diagram of a two-dimensional image forming apparatus according to a ninth embodiment of the present invention. In the above embodiment, the polygon mirror 14 and the galvanometer mirror 15 are used as the movable mirrors, but the same operation can be performed using two galvanometer mirrors. In this embodiment, two galvanometer mirrors 15 and 16 are used as an example of a movable mirror instead of a lenticular lens, and the other points are the same as those of the two-dimensional image forming apparatus shown in FIG. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  The galvanometer mirror 16 reflects the light beam emitted from the laser light source 1 and deflects it in the X direction. The galvanometer mirror 15 further reflects the light beam reflected by the galvanometer mirror 16 and deflects it in the Y direction. Dimensional beam deflection.

  With the above configuration, in this embodiment, the deflection angle of the light beam can be accurately controlled by the galvanometer mirrors 15 and 16, so that the light emitted from the pupil of the projection lens 8 and the two-dimensional spatial light modulator 7 Since there is no loss of light that irradiates outside the image frame, an optical system with very little light loss can be realized. In this embodiment, two galvanometer mirrors are used, but the same effect can be obtained even when two polygon mirrors are used.

(Tenth embodiment)
FIG. 14 is a schematic configuration diagram of a two-dimensional image forming apparatus according to the tenth embodiment of the present invention. In each of the above embodiments, one laser light source is used. However, the present invention can also be applied to a case where a full color image is formed using each of the red, green, and blue laser light sources. In the present embodiment, a color image is displayed using the red laser light source 1a, the green laser light source 1b, and the blue laser light source 1c.

  The light beams emitted from the red laser light source 1a, the green laser light source 1b, and the blue laser light source 1c pass through the prism arrays 2a to 2c and the rod integrators 4a to 4c, respectively, and the emission end faces of the rod integrators 4a to 4c. The beam has a uniform intensity distribution. Each prism array 2a to 2c is provided with a drive unit that rotates each prism array 2a to 2c, as in the first embodiment. However, for ease of illustration, FIG. Omitted.

  The light beam emitted from the rod integrator 4a is reflected by the mirror 17a through the projection optical system 5a, illuminates the two-dimensional spatial light modulator 7a via the field lens 6a, and the light beam emitted from the rod integrator 4b is projected optically. The light beam that is guided to the field lens 6b through the system 5b, illuminates the two-dimensional spatial light modulator 7b, and exits the rod integrator 4c is reflected by the mirror 17c through the projection optical system 5c, and is two-dimensionally transmitted through the field lens 6c. The spatial light modulation element 7c is illuminated.

  The dichroic prism 18 has a function of reflecting red light incident from the upper side of the drawing in the left direction, reflecting blue light incident from the lower side of the drawing in the left direction of the drawing, and transmitting green light incident from the right side of the drawing. Have. All the images on the three two-dimensional spatial light modulators 7 a to 7 c are projected on the screen 19 by the projection lens 8. At this time, video signals corresponding to red, green, and blue are respectively input to the three two-dimensional spatial light modulators 7 a to 7 c, and a full-color video is displayed on the screen 19.

  With the above configuration, the present embodiment has the same effects as the first embodiment, can display a full-color image, and further uses the projection lens 8 for each color light. In addition, the number of parts can be reduced. In this embodiment, a prism array is used as the beam deflecting unit. However, a lenticular lens, a diffuser plate, a rotationally symmetric lens, a galvanometer mirror, a polygon mirror, and other beam deflecting units may be used.

(Eleventh embodiment)
FIG. 15 is a schematic configuration diagram of a two-dimensional image forming apparatus according to an eleventh embodiment of the present invention. In the present embodiment, a dichroic prism 20 is installed in front of the incident side of the prism array 2, and a color image is displayed using the red laser light source 1a, the green laser light source 1b, and the blue laser light source 1c.

  The light beams emitted from the red laser light source 1a, the green laser light source 1b, and the blue laser light source 1c are combined by the dichroic prism 20 before entering the prism array 2 and the rod integrator 4, and light beams of all colors are obtained. Both follow the same optical path and enter the prism array 2 to be deflected. The prism array 2 is provided with a drive unit for rotating the prism array 2 as in the first embodiment, but is omitted in FIG. 15 for ease of illustration.

  Thereafter, the light beam deflected by the prism array 2 is converted into a light beam having a uniform intensity distribution by the rod integrator 4, and the behavior of each light beam until reaching the screen 8 is the same as in the first embodiment. It is the same as the form. This embodiment is different from the first embodiment in that it adopts a control method called so-called sequential lighting as described below.

  Red, green, and blue video signals are sequentially switched and input on the two-dimensional spatial light modulator 7, and a red laser light source 1a, a green laser light source 1b, and a blue laser light source 1c are synchronized with each video signal. Are lit in sequence. As a result, images of the respective colors are sequentially projected on the screen 19. In this way, by switching at high speed so that red, green, and blue are lit several times for each frame of the video signal, the images of the respective colors are observed in an overlapping manner, and a full-color image is sensed.

  The present embodiment can achieve the same effects as the tenth embodiment, and the prism array 2, the drive unit, the rod integrator 4, the projection lens 5, the field lens 6, and the two-dimensional spatial light modulator 7 are provided. Since all are used in common for red, green, and blue, the number of optical components is reduced, and a full color video display is possible with a small configuration.

  In each of the above embodiments, the projection optical system 5 and the screen have been described as examples of the projection display. However, the present invention combines the projection optical system 5 and the transmission screen. The present invention can also be applied to a rear projection type two-dimensional image forming apparatus. Although a color image projection apparatus has been described as an example, the present invention can also be used for a monochromatic laser image projection apparatus, such as a semiconductor exposure apparatus.

  As described above, the two-dimensional image forming apparatus according to the present invention includes at least one laser light source, a beam deflecting unit that changes a traveling direction of a light beam emitted from the laser light source, and the beam deflecting unit. Driving means for driving the beam deflecting means to change the traveling direction of the light beam to be temporally, a rod integrator for guiding the light beam deflected by the beam deflecting means to the exit end while internally reflecting, and the rod From the first projection optical system that projects the light beam emitted from the integrator, the two-dimensional spatial light modulation element that modulates the light beam emitted from the first projection optical system, and the two-dimensional spatial light modulation element And a second projection optical system that projects the emitted light onto a predetermined surface.

  In this two-dimensional image forming apparatus, the light beam emitted from the laser light source is deflected at different angles by the beam deflecting means and the driving means, and the deflected light beam is internally reflected by the rod integrator while being reflected at the exit end. The light beam guided and emitted from the rod integrator is projected onto the two-dimensional spatial light modulation element by the first projection optical system, and the light emitted from the two-dimensional spatial light modulation element is predetermined by the second projection optical system. Projected onto the surface of At this time, the light beam can be deflected at different angles in time by the beam deflecting means disposed between the laser light source and the rod integrator without disposing a diffusion plate immediately before the two-dimensional spatial light modulator. Therefore, it is possible to reduce the loss of light by irradiating the outside of the image frame of the two-dimensional spatial light modulation element, and it is possible to reduce speckle noise with an optical system having a very small light loss. Also, since the light beam intensity distribution is made constant by using a small rod integrator without expanding the light beam emitted from the laser light source, there is no need to use a large beam expander and light integrator. The system can be miniaturized. As a result, speckle noise can be reduced, light loss can be reduced, and the optical system can be downsized.

  The beam deflecting unit preferably includes a prism array in which minute prisms are two-dimensionally arranged. In this case, since the deflection angle of the light beam can be accurately controlled by the prism array, the loss caused by irradiating the light from the lens pupil of the second projection optical system or the image frame of the two-dimensional spatial light modulator is lost. Can be reduced, and an optical system with very little light loss can be realized.

  The beam deflecting unit preferably includes a lenticular lens having optical axes arranged substantially at right angles to each other. In this case, since the deflection angle of the light beam can be accurately controlled by the lenticular lens, light lost from the pupil of the lens of the second projection optical system or the outside of the image frame of the two-dimensional spatial light modulator is lost. Can be reduced, and an optical system with very little light loss can be realized. Further, since the surface shape of the lenticular lens is smooth, there is no light scattering due to the boundary line as in the prism, so that an optical system with less loss can be realized.

  The lenticular lens includes a first substrate on which a first lenticular lens that horizontally deflects a light beam emitted from the beam deflecting unit is formed, and a light beam emitted from the beam deflecting unit in a vertical direction. And a second substrate on which a second lenticular lens to be deflected is formed. In this case, since the polarization direction of the light passing through the first and second lenticular lenses does not change, generation of unnecessary polarization components is suppressed, and linearly polarized light is incident on the two-dimensional spatial light modulator with a small loss. And an optical system with less loss can be realized.

  In the lenticular lens, a first lenticular lens that horizontally deflects the light beam emitted from the beam deflection unit is formed on one surface, and the light beam emitted from the beam deflection unit on the other surface. It is also possible to include a substrate on which a second lenticular lens that vertically deflects is formed. In this case, since the polarization direction of the light passing through the lenticular lens does not change, generation of unnecessary polarization components can be suppressed, and linearly polarized light can be incident on the two-dimensional spatial light modulator with a small loss. A small number of optical systems can be realized, and since the lenticular lens can be formed from a single substrate, the number of components can be reduced and the configuration of the driving means can be simplified.

  The beam deflecting unit preferably includes a diffusion plate. In this case, the light beam can be deflected at different angles in time by disposing a diffuser plate between the laser light source and the rod integrator without disposing a diffuser plate immediately before the two-dimensional spatial light modulator. Further, it is possible to reduce light that is lost by irradiating the outside of the image frame of the two-dimensional spatial light modulation element, and it is possible to realize an optical system with small light loss.

  The diffusion plate is preferably a pseudo random diffusion plate. In this case, it is possible to reduce the light that is lost by irradiating the outside of the image frame of the two-dimensional spatial light modulator, and to reduce the light emitted from the lens pupil of the second projection optical system. An optical system with smaller light loss can be realized.

The beam deflecting unit preferably includes a lens. In this case, since the deflection angle of the light beam can be accurately controlled by driving the lens two-dimensionally, the light emitted from the lens pupil of the second projection optical system and the two-dimensional spatial light modulation element Light that is lost by irradiating outside the image frame can be reduced, and an optical system with very little light loss can be realized. Further, Runode not use a smaller lens from the lenticular lens, it is possible to realize a more compact optical system.

  The beam deflecting unit and the driving unit preferably include a movable mirror that drives the mirror two-dimensionally. In this case, since the deflection angle of the light beam can be accurately controlled by the movable mirror that drives the mirror two-dimensionally, the light emitted from the pupil of the lens of the second projection optical system and the two-dimensional spatial light modulator It is possible to reduce the loss of light by irradiating the outside of the image frame, and it is possible to realize an optical system with very little light loss. Further, when a MEMS mirror is used as the movable mirror, the MEMS mirror is much smaller than the lenticular lens, so that a further compact optical system can be realized.

  The two-dimensional spatial light modulator is preferably a reflective two-dimensional spatial light modulator. In this case, since it is not necessary to place a diffusion plate in front of the reflective two-dimensional spatial light modulator, it is possible to prevent a decrease in the amount of light.

  The laser light source includes three laser light sources that respectively generate blue light, green light, and red light. The beam deflecting unit, the rod integrator, the first projection optical system, and the two-dimensional spatial light modulation. The elements are preferably arranged individually for each of the three laser light sources. In this case, a full-color image can be displayed and the second projection optical system can be shared by the light of each color, so that the number of parts can be reduced.

  The laser light source includes three laser light sources that respectively generate blue light, green light, and red light, and further includes a light combining unit that combines light from the three laser light sources, and the light combined by the light combining unit is The light beam may be incident on the beam deflecting means. In this case, a full-color image can be displayed, and the beam deflecting unit, the driving unit, the rod integrator, the first projection optical system, the two-dimensional spatial light modulation element, and the second projection optical system are changed to light of each color. Since they can be shared, the number of parts can be further reduced.

  The two-dimensional image forming apparatus according to the present invention does not generate loss light by irradiating the outside of the image frame of the two-dimensional spatial light modulator, and the speckle noise can be reduced by an optical system with very little light loss. This is effective as a two-dimensional image forming apparatus that uses a coherent light source as a light source.

1 is a schematic configuration diagram of a two-dimensional image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic perspective view for mainly explaining a configuration of a prism array shown in FIG. 1. It is a schematic block diagram of the two-dimensional image forming apparatus by the 2nd Embodiment of this invention. It is a schematic block diagram of the two-dimensional image forming apparatus by the 3rd Embodiment of this invention. FIG. 5 is a schematic perspective view for mainly explaining the configuration of the lenticular lens shown in FIG. 4. It is a schematic block diagram of the two-dimensional image forming apparatus by the 4th Embodiment of this invention. It is a figure showing arrangement | positioning of the uneven | corrugated shape of a lenticular lens in the two-dimensional image forming apparatus shown in FIG. It is a schematic block diagram of the two-dimensional image forming apparatus by the 5th Embodiment of this invention. It is a schematic block diagram of the two-dimensional image forming apparatus by the 6th Embodiment of this invention. FIG. 10 is a diagram illustrating a planar configuration of a pseudo random diffuser plate used in the two-dimensional image forming apparatus illustrated in FIG. 9. It is a schematic block diagram of the two-dimensional image forming apparatus by the 7th Embodiment of this invention. It is a schematic block diagram of the two-dimensional image forming apparatus by the 8th Embodiment of this invention. It is a schematic block diagram of the two-dimensional image forming apparatus by the 9th Embodiment of this invention. It is a schematic block diagram of the two-dimensional image forming apparatus by the 10th Embodiment of this invention. It is a schematic block diagram of the two-dimensional image forming apparatus by the 11th Embodiment of this invention. It is a schematic block diagram of the conventional laser display.

Claims (11)

At least one laser light source;
Beam deflecting means for changing a traveling direction of a light beam emitted from the laser light source;
Driving means for driving the beam deflecting means to temporally change the traveling direction of the light beam emitted from the beam deflecting means;
A rod integrator for guiding the light beam deflected by the beam deflecting means to the exit end while internally reflecting;
A first projection optical system that projects a light beam emitted from the rod integrator;
A two-dimensional spatial light modulator for modulating a light beam emitted from the first projection optical system;
And a second projection optical system for projecting light emitted from the two-dimensional spatial light modulation element onto a predetermined surface,
2. The two-dimensional image forming apparatus according to claim 1, wherein the beam deflecting unit includes a prism array in which minute prisms are two-dimensionally arranged . At least one laser light source;
Beam deflecting means for changing a traveling direction of a light beam emitted from the laser light source;
Driving means for driving the beam deflecting means to temporally change the traveling direction of the light beam emitted from the beam deflecting means;
A rod integrator for guiding the light beam deflected by the beam deflecting means to the exit end while internally reflecting;
A first projection optical system that projects a light beam emitted from the rod integrator;
A two-dimensional spatial light modulator for modulating a light beam emitted from the first projection optical system;
A second projection optical system that projects light emitted from the two-dimensional spatial light modulation element onto a predetermined surface;
2. The two- dimensional image forming apparatus according to claim 1, wherein the beam deflection means includes a lenticular lens having optical axes arranged substantially perpendicular to each other. The lenticular lens is
A first substrate on which a first lenticular lens for deflecting a light beam emitted from the beam deflecting means in a horizontal direction is formed;
3. The two-dimensional image forming apparatus according to claim 2 , further comprising: a second substrate on which a second lenticular lens that deflects the light beam emitted from the beam deflecting unit in the vertical direction is formed. In the lenticular lens, a first lenticular lens that horizontally deflects the light beam emitted from the beam deflection unit is formed on one surface, and the light beam emitted from the beam deflection unit on the other surface. 3. The two-dimensional image forming apparatus according to claim 2 , further comprising a substrate on which a second lenticular lens for deflecting the lens in the vertical direction is formed. It said beam deflection means, the two-dimensional image forming apparatus according to any one of claims 1 or 2 characterized in that it comprises a diffuser. The two-dimensional image forming apparatus according to claim 5 , wherein the diffusion plate is a pseudo random diffusion plate. It said beam deflection means, the two-dimensional image forming apparatus according to any one of claims 1 or 2 characterized in that it comprises a lens. At least one laser light source;
Beam deflecting means for changing a traveling direction of a light beam emitted from the laser light source;
Driving means for driving the beam deflecting means to temporally change the traveling direction of the light beam emitted from the beam deflecting means;
A rod integrator for guiding the light beam deflected by the beam deflecting means to the exit end while internally reflecting;
A first projection optical system that projects a light beam emitted from the rod integrator;
A two-dimensional spatial light modulator for modulating a light beam emitted from the first projection optical system;
A second projection optical system that projects light emitted from the two-dimensional spatial light modulation element onto a predetermined surface;
The two- dimensional image forming apparatus, wherein the beam deflecting unit and the driving unit include a movable mirror for driving the mirror two- dimensionally. The two-dimensional spatial light modulator, the reflection type two-dimensional image forming apparatus according to any one of claims 1 to 8 which is characterized in that a two-dimensional spatial light modulator. The laser light source includes three laser light sources that generate blue light, green light, and red light, respectively.
The beam deflecting means, the rod integrator, the first projection optical system, and the two-dimensional spatial light modulation element are individually arranged for each of the three laser light sources. The two-dimensional image forming apparatus according to any one of claims 1 to 9 . The laser light source includes three laser light sources that generate blue light, green light, and red light, respectively.
A light combining means for combining the light from the three laser light sources;
The light combined by the combining means, the two-dimensional image forming apparatus according to any one of the beam deflecting means according to claim was characterized in that it is incident on the 1-9.

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