JP2006343413A - Image producing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce speckle by arranging a diffuser having wavelength selectivity at an intermediate image forming position and also to sufficiently extend luminous flux of every wavelength relative to the diameter of the entrance pupil of a projection optical system without remarkably lowering the efficiency of using light. <P>SOLUTION: The image producing device 1 is constituted by arranging: a light source part having coherent light sources (2R, 2G and 2B) having different wavelength; an optical system 6 receiving light from the light source part and forming an intermediate image; a light scattering part 7 arranged at the intermediate image forming position; and a projection optical system 8 arranged at the post-stage of the light scattering part. The light scattering part 7 is constituted to scatter the light for every wavelength by using a plurality of diffraction gratings having the wavelength selectivity for each wavelength of the light source. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique effective in reducing speckles and improving safety in an image generation apparatus using a coherent light source.

  In a projection-type image display device using a laser light source, for example, it is obtained by irradiating a linear beam onto a one-dimensional spatial modulation type light modulation element and modulating light using the light modulation element. A two-dimensional image can be formed by projecting a one-dimensional image onto a screen via a projection lens system while scanning along a direction orthogonal to the one-dimensional direction with an optical scanning unit such as a galvanometer.

  In an image generating apparatus using a laser as a light source, speckles due to high coherence are regarded as a problem. That is, particulate noise (speckle noise) is generated on the screen, which causes the image quality to deteriorate.

  In display devices using laser light, the following methods are known as speckle reduction methods.

(A) A diffuser (an optical element for light scattering) is installed at the intermediate image position, and the diffuser is vibrated to generate temporally different speckle patterns, and noise is not noticeable due to the effect of visual averaging. (B) In a configuration using a one-dimensional type light modulation element, a diffuser is installed at a one-dimensional intermediate image position by the element, and then light scanning (scanning) is performed on the screen. A method for reducing speckles in a two-dimensional image (for example, see Patent Document 1).

  In the above (B), the speckle reduction effect can be enhanced by increasing the diffraction scattering angle by the diffuser and widening the light flux entering the entrance pupil of the projection lens.

US Pat. No. 6,323,984

  However, in the conventional apparatus, there is a problem when a common diffuser is used for a plurality of different wavelengths, for example, three primary colors (RGB). Since the diffraction scattering angle increases in proportion to the wavelength of the light source, for example, when trying to spread a green beam (the wavelength with the highest speckle visibility) within the pupil diameter of the projection lens, a red beam with a long wavelength is generated. There is a problem that vignetting occurs due to excessive expansion, resulting in a significant reduction in efficiency.

  Therefore, the present invention reduces the speckle by arranging a diffuser having wavelength selectivity at the formation position of the intermediate image, and emits the light flux of each wavelength without significantly reducing the light utilization efficiency. The problem is to expand sufficiently.

  In order to solve the above-described problems, the present invention provides a light source unit having a coherent light source that outputs light having different wavelengths, an optical system that receives light from the light source unit, and forms an intermediate image. A light scattering portion disposed at the formation position and a projection optical system disposed at a subsequent stage of the light scattering portion, and the light scattering portion includes a plurality of diffraction gratings having wavelength selectivity with respect to each wavelength of the coherent light source. It is used and is configured to scatter light according to the wavelength.

  Therefore, in the present invention, the diffraction scattering angle and the diffraction grating surface are independently designed for each wavelength of the light source by using a plurality of diffraction gratings having wavelength selectivity in the light scattering portion arranged at the intermediate image forming position. be able to. That is, the beam divergence angle and the position of the diffractive surface are defined according to the wavelength and then incident on the projection optical system.

  According to the present invention, in application to an image generation apparatus using a coherent light source, image quality is improved by increasing the speckle reduction effect, and light beams of each wavelength are projected without significant decrease in light utilization efficiency. It can be expanded sufficiently with respect to the pupil diameter of the system, and is effective in improving safety.

  Further, according to the configuration in which the diffraction gratings corresponding to the respective wavelengths are shifted in position along the optical axis of the optical system in the light scattering portion, the position of the intermediate image plane can be arranged for each wavelength. This is effective in reducing longitudinal chromatic aberration.

  In addition, by setting the scattering angle by the diffraction grating corresponding to each wavelength for each wavelength, the degree of freedom in optical design can be increased, and the desired luminous flux can be expanded without significantly reducing the light utilization efficiency. It is possible to take sufficient safety measures.

  In a configuration in which the light source unit includes a laser light source and a light modulation element, and an image obtained by light modulation using the light modulation element is formed at an intermediate image position by a relay optical system, Contributes to improved usage efficiency and image quality. For example, in an apparatus that uses a one-dimensional light modulation element as a light modulation element and makes a two-dimensional image by scanning a one-dimensional image by a relay optical system in a direction orthogonal to the direction in which the one-dimensional image is formed by an optical scanning unit. A configuration suitable for high image quality and high performance is realized, and it is useful for downsizing and cost reduction.

  An object of the present invention is, for example, to enhance speckle reduction effect and take sufficient safety measures in an image generation apparatus that performs image display, image output, and the like using a plurality of coherent light sources and light modulation elements having different wavelengths. And

  In the application of the present invention, the type and configuration of the coherent light source and the light modulation element are not limited. For example, a one-dimensional image formed by a one-dimensional spatial modulation type light modulation element or the like using a laser light source is converted into a galvanometer. The present invention can be applied to an image display device that forms a two-dimensional intermediate image by scanning with an optical scanning means such as a printer, or an image output device such as a printer.

  FIG. 1 illustrates an outline of a basic configuration when an image generation apparatus 1 according to the present invention is applied to a front projection type image display apparatus.

  In this example, the light output from the coherent light source 2 reaches the light modulation unit 4 through the illumination optical system 3, and the light modulated here is the color synthesis unit 5 and the optical system 6 (including a spatial filter). The light reaches the projection and light scanning system 8 via the light scattering unit 7.

  A plurality of light sources are used as the coherent light source 2. For example, laser light sources 2R, 2G, and 2B using a semiconductor laser, a solid-state laser, and the like are provided for each wavelength of R (red), G (green), and B (blue), and power is supplied from a power supply unit (not shown). In response, a laser beam having a wavelength corresponding to each color is output.

  The illumination optical system 3 is provided to irradiate the laser beam to the light modulation unit 4 with a predetermined light intensity profile. In this example, the beam output from each laser light source has a role of converting it into a one-dimensional linear beam, and is configured using a beam expanding optical system, a line generator, or the like. Note that optical systems 3R, 3G, and 3B corresponding to the respective colors of R, G, and B are used.

  For the light modulation unit 4, for example, a one-dimensional light modulation element is used. Intensity distribution composed of one-dimensional light modulation elements 4R, 4G, and 4B corresponding to each color of R, G, and B, and uniformized through the optical systems 3R, 3G, and 3B (so-called “top hat” distribution) Each element is irradiated with a linear beam. As the one-dimensional light modulation element, for example, a GLV (Grating Light Valve) element can be used. In the case of a reflective diffraction grating, a plurality of movable ribbons and fixed ribbons are alternately arranged along a predetermined direction. For example, when six ribbon elements constituting one pixel are provided and every three movable ribbons and every other fixed ribbon are arranged, 6480 in 1080 pixels for one line. Ribbon elements are arranged along a one-dimensional direction (pixel arrangement direction). For the first surface, which is the surface of the movable ribbon, and the second surface, which is the surface of the fixed ribbon, with respect to the laser light irradiation surface, aluminum copper (AlCu) alloy or the like is used, and the surfaces are alternately arranged. In addition, the movable ribbon is moved in response to a drive signal from a drive controller (9) described later, and the position of the first surface is controlled in the direction along the irradiation direction of the laser beam. That is, when a driving voltage corresponding to an image signal is applied, the movable ribbon moves with a displacement amount corresponding to the driving voltage, and in this state (so-called pixel on), a reflection type diffraction grating for incident light is formed ( Generation of first-order diffracted light). Further, in a state where the displacement amount is made uniform with the fixed ribbon without moving the movable ribbon (so-called pixel off), the first-order diffracted light is not generated (only regular reflection with respect to the incident light).

  In addition, in the form using the GLV element, features such as being capable of high-speed operation control and being able to be driven with a low operating voltage when displaying a high resolution image with a wide bandwidth are obtained. The application of the present invention is not limited to a one-dimensional spatial modulation element, and may be a configuration using a two-dimensional spatial modulation element. Further, the present invention is not limited to the light source unit including the light source 2, the illumination optical system 3, and the light modulation unit 4, and can be applied to a configuration using a self-luminous device for the light source unit.

  In FIG. 1, the reflected light and diffracted light of the illumination light irradiated on the one-dimensional light modulation elements 4R, 4G, 4B are generated, and the color combining unit 5 combines the modulated color lights, and then the optical system. Reach 6

  The optical system 6 includes an optical element and a spatial filter and receives light from the light source unit to form an intermediate image at a predetermined position. The spatial filter has a function of selecting a diffracted light component of a specific order. For example, a schlieren filter is used to extract ± first-order diffracted light out of light modulated using the one-dimensional light modulation elements 4R, 4G, and 4B. (0th-order light not used for image display is shielded).

  A light scattering portion 7 is disposed at a position where an intermediate image is formed by the optical system 6, and a light scattering element (so-called “diffuser”) having selectivity with respect to the wavelength of each laser light source as will be described in detail later. Is used.

  A projection and optical scanning system 8 is arranged at the subsequent stage of the light scattering unit 7 and has the above-mentioned intermediate image projection function and two-dimensional imaging function by optical scanning. For example, the following configuration forms are mentioned.

A configuration in which the optical scanning system is arranged in the subsequent stage of the projection system. A configuration in which the projection system is arranged in the subsequent stage of the optical scanning system. An integrated configuration in which the optical scanning system is included in the projection system.

  For example, a galvanometer is used in the optical scanning system, and a two-dimensional image is formed by receiving incident light of a one-dimensional image. That is, when the formation direction of the one-dimensional image is the “first direction”, the direction corresponds to the major axis direction of the one-dimensional light modulation element, and the “second direction” is orthogonal to the first direction. A two-dimensional image is formed by performing optical scanning along the “direction of”.

  The two-dimensional image obtained by optical scanning is enlarged and projected on the screen “SCN” by the action of the projection optical system, and image display is performed.

  The drive control of the light modulation unit 4 is performed by the drive control unit 9 in accordance with a video signal indicated by “VIDEO” in the drawing. For example, the video signal is converted from a color difference signal to an RGB color signal. If a nonlinear characteristic such as a γ (gamma) characteristic is given, the color for conversion to the color reproduction range of the illumination light source is obtained after conversion to the linear characteristic by performing reverse correction. Spatial conversion processing and the like are performed. The output signal of the drive control unit 9 is supplied to the one-dimensional light modulation elements via the drive circuits of the one-dimensional light modulation elements 4R, 4G, and 4B, whereby the laser light modulation control is performed for each color. .

  The optical scanning control unit 10 performs drive control (for example, rotation control of a galvano mirror) of optical elements constituting the projection and optical scanning system 8. That is, control is performed to scan a two-dimensional image of a one-dimensional image obtained by light modulation using the one-dimensional light modulation elements 4R, 4G, 4B, and a synchronization signal indicated by “SYNC” in the figure. In accordance with the control signal, a control signal is sent to the projection and optical scanning system 8 to control the operation of the mechanism.

  2 and 3 show an example of the optical configuration of the main part of the image generation apparatus, and FIG. 2 is viewed from the direction along the major axis direction (pixel arrangement direction) of the one-dimensional light modulation element. FIG. 3 shows a configuration diagram, and FIG. 3 shows a light modulation element 4c (“c” is an index representing color and shows one of R, G, and B when viewed from a direction orthogonal to the major axis direction. ), An optical system 6, a light scattering unit 7, a projection and light scanning system 8. In these figures, for the laser light source, the illumination optical system, and the light modulation element, only a certain wavelength among the three primary colors is illustrated for convenience. However, in an actual optical system, for each wavelength, as described above. A light source unit is provided, and each color light is combined in the color combining unit 5.

  In FIG. 2, a beam emitted from a laser light source 2 c (“c” is an index representing color and represents any of R, G, and B) is emitted from a diverging lens 11 and a collimating lens in an illumination optical system 3. 12. The light passes through the cylindrical lens 13 and is irradiated to the one-dimensional light modulation element 4c. The cylindrical lens 13 has power in a plane parallel to the paper surface of FIG. 2, and has no power in a plane orthogonal to the paper surface.

  For example, a reflection type diffraction grating is used for the one-dimensional light modulation element 4c, and the arrangement direction thereof is a direction perpendicular to the paper surface of FIG. 2 (or the longitudinal direction of the element 4c in FIG. 3). The reflected light and diffracted light from the one-dimensional light modulation element 4c are transmitted through the optical system 6 (relay optical system) in the order of the first relay lens 14, the Schlieren diaphragm 15, and the second relay lens 16. For example, the 0th-order light is shielded at the Schlieren stop 15, and the ± 1st-order diffracted light selectively passes through and reaches the subsequent light scattering section 7. The application of the present invention is not limited to a relay optical system using a lens as shown in the figure, but is an Offner relay optical system (for example, an optical in which a schlieren stop is installed in a secondary mirror using a primary mirror and a secondary mirror). Or the like, and can be applied to various optical systems that receive light from the light source unit to form an intermediate image.

  A light scattering element is provided on the image plane of the one-dimensional intermediate image formed after passing through the optical system 6, and light scattered by diffraction for each wavelength using the element is projected and scanned by the optical scanning system 18. On the screen “SCN”. In the projection and light scanning system 8, for example, a projection optical system 17 (only a projection lens is shown in the figure) is disposed in the preceding stage, and a light beam diffused by a light scattering element is incident thereon. An optical scanning system 18 (shown in FIG. 2 shows a rotating reflecting mirror 19 having a rotation axis “R” perpendicular to the paper surface) is disposed downstream of the projection optical system 17 and is synchronized with the image signal. A one-dimensional image is converted into a two-dimensional image by scanning and projected onto a screen.

  For the light scattering element installed at the intermediate image forming position, a plurality of diffraction gratings are formed using a material having wavelength selectivity with respect to the wavelength of each light source. That is, it has a feature that it has a diffraction effect only for a specific wavelength, and the diffraction effect for other light source wavelengths is sufficiently small that the influence on image quality can be ignored. .

(I) Configuration in which diffraction gratings corresponding to one wavelength are respectively formed (II) A combination of diffraction gratings corresponding to a plurality of wavelengths, or a combination of the diffraction grating and the diffraction grating of (I) above

  First, in (I), for example, with respect to the wavelengths corresponding to the three primary colors (R, G, B), there is a difference in refractive index at one wavelength, but the same or almost the same refractive index at the remaining two wavelengths. A composite structure in which materials having a refractive index (for example, organic materials such as a photocurable resin and a thermosetting resin containing an organic pigment) are combined is used. That is, these materials are arranged on a substrate (synthetic quartz, glass, etc.) with a constant repetition period (diffraction pitch) by a photolithography technique to form a lattice pattern.

For example, in the light scattering element 20 having the wavelength selective diffraction grating as shown in FIG. 4A, it corresponds to red light (for example, λ _R = 640 nm when the wavelength is described as “λ _R ”). The diffraction grating 20R, the diffraction grating 20G corresponding to green light (when its wavelength is denoted as “λ _G ”, for example, λ _G = 530 nm), and blue light (its wavelength is denoted as “λ _B ”), for example, diffraction grating 20B corresponding to (λ _B = 450 nm) is formed in a state of being shifted with a predetermined interval (see diffraction grating surface intervals “d1” and “d2”, for example, about 100 μm). .

The diffraction grating 20R is formed by combining materials having a refractive index difference at the wavelength λ _R and having almost no refractive index difference at the wavelengths λ _{G and} λ _B , so that a diffractive action with respect to red light can be obtained and green light can be obtained. And blue light have no diffraction effect (only transmission effect). Likewise, the diffraction grating 20G has a refractive index difference at the wavelength lambda _G, and the wavelength lambda _R, the refractive index difference in lambda _B is formed by combining a little material, the diffraction grating 20B is refracted at the wavelength lambda _B It is formed by combining materials having a difference in refractive index and having almost no refractive index difference at wavelengths λ _R and λ _G.

  FIG. 5B is a conceptual explanatory diagram showing the state of diffraction with respect to incident light having a specific wavelength, where “20c” represents a diffraction grating (“c” is one of R, G, and B). Is a color index indicating.).

  Regarding the incident angle to the light scattering element (see “θin”), for example, about ± 10 ° is an allowable range. That is, the angle is required to be small with respect to the diffraction angle of the high-order diffracted light.

  The diffraction angle of the third-order diffracted light (see “θ3”) is, for example, about ± 9 ° with respect to the zeroth-order light. If the allowable range is excessively widened, it is necessary to increase the numerical aperture (NA) of the projection lens, which causes an increase in the cost of the projection lens.

  The fourth-order or higher diffracted light ratio is preferably less than 10% in consideration of efficiency and the like. With respect to the variation of the + 3rd to -3rd order diffracted light amounts, it is preferable to set the light amount average value of each order to be ± 50% or less (if the light amount distribution is concentrated on the exit pupil of the projection lens, it is necessary for laser safety measures). This may cause problems and is not preferable.) The diffraction efficiency can be changed depending on the grating height and the grating shape.

  Further, regarding the wavelength selectivity of each color of R, G, and B, diffracted light of the remaining two wavelengths (for example, each wavelength of G color and B color) on the basis of the wavelength to be designed (for example, wavelength of R color) It is desirable to minimize the strength (for example, the relative strength ratio is less than 5%). That is, scattering due to diffraction on a surface different from the imaging position leads to a decrease in resolution on the screen when applied to an image projection apparatus, for example, and thus it is required that such a problem does not occur.

  The diffraction scattering angle and the diffraction grating surface position can be designed independently for each of the three primary colors.

  Since the repetition period related to the diffraction grating corresponds to the diffraction scattering angle, and the diffraction scattering angle is proportional to the wavelength, if the repetition period is defined according to the wavelength, the diffraction scattering angle does not depend on the wavelength, or (In other words, the diffraction scattering angle Δθ is proportional to the wavelength “λ” and is inversely proportional to the repetition period “p”. The p value is proportional to the wavelength λ.) .

  In addition, although each element including each diffraction grating can be independently created and arranged, it is better to create them as elements integrated as described above in terms of downsizing, accuracy, manufacturing man-hours, etc. Desirable from.

  In the above (II), for example, for a wavelength corresponding to two specific colors, a combination of materials having wavelength selectivity is used, and this is arranged on a substrate with a constant repetition period by a photolithography technique. Form a pattern.

  In the light scattering element 21 having the wavelength selective diffraction grating shown in FIG. 5, a diffraction grating 21R corresponding to red light and a diffraction grating 21GB corresponding to a wavelength range including green light and blue light are separated by a predetermined distance (diffraction). (Lattice plane spacing) and are shifted in position.

The diffraction grating 21R is formed by combining materials having a refractive index difference at the wavelength λ _R and having almost no refractive index difference at the wavelengths λ _{G and} λ _B , thereby obtaining a diffractive action with respect to red light. And blue light have no diffraction effect (only transmission effect). The diffraction grating 21GB has a refractive index difference in the wavelength range including the wavelength lambda _G and lambda _B, and the refractive index difference at a wavelength lambda _R is formed by combining a little material.

  Such a configuration can be applied to, for example, an optical system that takes into account the demand for high specific visibility for green and a sufficient scattering angle of the green luminous flux, or to a multi-primary color reproduction system. It is effective in the application of.

  A diffraction grating type light scattering element having wavelength selectivity with respect to a light source wavelength can be manufactured with high accuracy, for example, as an organic planar optical element, and by controlling the grating plane spacing by adopting a laminated structure according to the wavelength. In addition to controlling the grating pitch and grating height, wavelength selectivity can be realized by selecting materials and combinations of materials. On the manufacturing side, mass production by mask process and high degree of freedom of design are achieved by using technologies that have been proven in the field of hologram elements used for reproducing heads and recording heads such as optical disks and magneto-optical disks. Etc. can be utilized.

  FIG. 6 shows the diffraction gratings 20R, 20G, and 20B (shown by broken lines in the figure) having selectivity for the wavelengths of the three primary colors in the form (I) above, with the optical axis of the optical system (in the figure). (Refer to the “LL” line.) This optical axis coincides with the optical axis of the relay optical system and the projection optical system, and a light scattering element is disposed at the intermediate image position.

  In designing the diffraction grating, the following items are performed independently.

(A) Shift the diffraction surface for each wavelength in the optical axis direction. (B) Change the diffraction grating interval (pitch) for each wavelength.

  First, in (a) above, the distance between the diffraction grating surfaces on the optical axis is used as a design parameter. For example, when the surface distance between the diffraction gratings 20R and 20G is denoted as “d1” and the surface distance between the 20G and 20B is denoted as “d2”, the d1 value and the d2 value do not need to be the same, A design freedom to arbitrarily change the d2 value within an allowable range is obtained. By setting the surface spacing of the diffraction grating, the problem of longitudinal chromatic aberration can be solved in application to an image projector or the like, which contributes to improvement in optical performance.

  In (b) above, the diffraction scattering angle can be set for each wavelength by changing the diffraction grating interval (grating period) for each wavelength. For example, as described above, it is possible to design the grating period in proportion to the wavelength so that the diffraction scattering angle does not depend on the wavelength, and even green light can obtain the same or almost the same diffraction angle as red light. And contributes to the expansion of the effective pupil diameter. In other words, the green light beam can be expanded within the pupil diameter of the projection lens to the same extent as the red light beam, there is no problem of vignetting of the red light beam, and there is no reduction in efficiency. In addition, expanding the luminous flux is effective as a measure for preventing failure due to laser light in terms of safety. In other words, the amount of light incident on the eyes of an observer mistakenly looking into the projection lens is sufficiently reduced, and the minimum size of light that forms an image on the retina is increased, which is effective in preventing damage and reducing exposure. is there.

  Arranging the light scattering element having the wavelength selectivity described above at the position of the intermediate image plane is effective for reducing speckles and is also required for maintaining the resolution. In other words, even when the intermediate image plane exists at a different position for each wavelength, the above-described configuration allows the diffraction grating planes corresponding to the wavelengths to be arranged separately without degrading the resolution. .

  As described above, according to the configuration in which light is diffracted and scattered for each wavelength using a light-scattering element having wavelength selectivity, long wavelength light (for example, red) can be applied to an image generation apparatus. The aperture can be used effectively by maximizing the luminous flux of each color to the entrance pupil diameter of the projection optical system without reducing the utilization efficiency. For example, the following advantages can be obtained.

The speckle reduction effect can be enhanced (contributes to the improvement of the S / N ratio), and for that purpose, the light utilization efficiency is not reduced, the configuration is complicated, and the cost is not significantly increased.
-The safety of the apparatus using the laser beam can be sufficiently guaranteed, and it is not necessary to reduce the laser beam output or the like for that purpose.
-Since the position of the intermediate image plane can be freely set for each wavelength, strict requirements are not imposed on the axial chromatic aberration of the projection optical system and the relay optical system (the allowable range for the axial chromatic aberration is widened).
・ Optical design flexibility is increased, the design margin is increased for improving the resolution performance of the projection optical system and the image distortion is reduced, and there is no need to use a special glass material for the optical element. Cost reduction is possible.

It is a figure which shows the basic structural example which concerns on this invention. It is a figure which shows the example of an optical structure of an image display apparatus with FIG. 3, This figure is the figure seen from the direction in alignment with the pixel array direction of a one-dimensional light modulation element. It is a figure which shows the structure of the principal part seen from the direction orthogonal to FIG. It is a figure for demonstrating the light-scattering element which concerns on this invention. It is a figure which shows another example about the light-scattering element which concerns on this invention. It is explanatory drawing about the structure which shifted the diffraction surface for the optical axis direction for every wavelength.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image generation device, 2 ... Coherent light source, 2R, 2G, 2B ... Laser light source, 4R, 4G, 4B ... Light modulation element, 6 ... Optical system, 7 ... Light scattering part, 17 ... Projection optical system, 20R, 20G 20B ... Diffraction grating, 21R, 21GB ... Diffraction grating

Claims (4)

A light source unit having a coherent light source that outputs light having different wavelengths, an optical system that receives light from the light source unit to form an intermediate image, a light scattering unit disposed at a position where the intermediate image is formed, and the light In the image generation apparatus provided with the projection optical system arranged in the subsequent stage of the scattering unit,
A plurality of diffraction gratings having wavelength selectivity with respect to each wavelength of the coherent light source are used in the light scattering unit, and the light generating unit is configured to scatter light according to the wavelength. The image generation apparatus according to claim 1,
The image generating apparatus, wherein the diffraction grating corresponding to each wavelength is arranged so as to be shifted in position along the optical axis of the optical system. The image generation apparatus according to claim 1,
An image generating apparatus, wherein a scattering angle by the diffraction grating corresponding to each wavelength is set for each wavelength. The image generation apparatus according to claim 1,
An image generating apparatus, wherein the light source section includes a laser light source and a light modulation element, and an image obtained by light modulation using the light modulation element is formed at an intermediate image position by a relay optical system.

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