JP2014164204A - Illumination device and display device employing the same - Google Patents

Abstract

The present invention provides a technique capable of displaying a high resolution and smooth image quality by maintaining a beam shape and reducing speckles in a laser scanning display device.
An illumination device for a light beam of a display device that scans and displays a coherent beam light is incident on the light beam having a coherent property, and the surface shape of a reflecting surface changes with time to generate a diffracted light beam. A reflective dynamic diffraction grating that reflects, a condensing unit that focuses n-th order diffracted light (n is an integer other than 0) out of the diffracted light reflected by the dynamic diffraction grating, and the condensing unit And a combining unit that combines the nth-order diffracted light collected at the portion and the 0th-order diffracted light of the diffracted light reflected by the dynamic diffraction grating as an output beam. The outgoing beam was scanned to display an image.
[Selection] Figure 1

Description

  The present invention relates to an illumination device for a display device that performs image display by scanning a beam of a coherent light source such as a semiconductor laser.

  With recent improvements in semiconductor laser technology, it has become possible to obtain a high-power optical output having a desired wavelength component. Furthermore, it has been applied to various applications by improving the efficiency of electro-optical conversion efficiency and reducing the size and cost by improving semiconductor devices and packaging technology. For example, an application to an image display device that draws an image using laser light having a wavelength component of visible light as a light source is also popular.

  On the other hand, since laser light has the characteristic of being coherent light having a uniform wavelength, speckles (fine particle-like bright spots) due to interference are observed when the object irradiated with the laser light is viewed. It is known to be visually recognized as noise. For this reason, various speckle noise reduction techniques have been proposed.

  For example, Patent Document 1 discloses a technique for eliminating spec noise by a method of vibrating a screen which is a diffusion plate or a method using a bundle fiber, and incoherent by modulating and controlling a current pulse for driving a laser diode. A method for reducing speckle noise in such a state is disclosed.

  Further, Patent Document 2 discloses that speckle noise is obtained by deflecting laser light with a rotating deflection element arranged in the traveling direction of the laser light, constantly changing a speckle noise pattern, and recognizing a time integral image. A method for reducing the above is disclosed.

  Patent Document 3 also includes an image lens that transmits a diffraction image modulated by a diffractive optical modulator to a scanner and a phase modulation unit, and a 0th-order diffracted light image is alternately projected and displayed on the first-order diffracted light image. A system and method is disclosed for removing the.

Japanese Patent Laid-Open No. 2001-18952 (page 12, FIG. 1) Japanese Patent No. 3595297 (page 5, FIG. 1) JP 2008-58963 A (page 13, FIG. 5)

  As disclosed in Patent Documents 1 and 2 above, an image display device that projects a laser beam by applying a laser beam to a MEMS mirror that oscillates in one or two axes and raster-scans the reflected light on an object. When the laser beam is configured, it is desirable that the laser beam be a parallel beam having a minute diameter. In this case, if a diffusing material is used, a reduction in beam quality, that is, a deterioration in video quality is inevitable. Further, the method of alternately projecting and displaying a first-order diffracted light image and a 0th-order diffracted light image disclosed in Patent Document 3 is modulation in units of planes, and speckle noise removal performance is limited.

  The present invention has been made in view of the problems of the incoherent technology described above, and an object thereof is to provide an illumination device that realizes speckle noise reduction with a small and low-profile mechanism and a display device using the same. And

  In order to solve the above-described problems, the beam light illumination device of the display device that performs display by scanning the coherent beam light according to the present invention is configured such that the coherent beam light is incident and the surface shape of the reflecting surface is Reflective dynamic diffraction grating that reflects diffracted light with time varying, and nth-order diffracted light (n is an integer other than 0) of the diffracted light reflected by the dynamic diffraction grating is focused to form an image. And a combining unit that combines the nth-order diffracted light collected by the condensing unit and the 0th-order diffracted light of the diffracted light reflected by the dynamic diffraction grating as an outgoing beam. In addition, an image is displayed by scanning the outgoing beam formed by the multiplexing unit.

  The dynamic diffraction grating includes a plurality of strip mirrors having a predetermined width arranged in one direction, and the strip mirror is movable in the incident direction of the beam light at a predetermined interval so as to move in the incident direction of the beam light. An uneven diffractive surface is formed on a vertical surface.

  According to another aspect of the present invention, there is provided a display device that scans and displays a coherent beam of light, a laser light source that emits a coherent beam of light modulated by video information, and a mirror that oscillates in one or two axes. A scanning mirror that reflects the beam light of the light source and raster-scans the beam light onto the object, and the 0th-order diffracted light and the nth-order diffracted light (n is an integer other than 0) that is split by the incidence of the coherent beam light. A coherence conversion unit is provided for condensing and emitting incoherent beam light, and the beam light converted by the coherence conversion unit is scanned by the scanning mirror for display.

  According to the present invention, speckle noise can be reduced while maintaining the beam shape, so that high-quality video display without a reduction in resolution is possible.

It is a block diagram of the illuminating device which concerns on 1st Example of this invention. It is a block diagram of the dynamic diffraction grating in 1st Example. It is a relationship figure explaining the relationship between the dynamic diffraction grating of 1st Example, and a beam. It is a state diagram of operation | movement of the strip mirror which comprises the dynamic diffraction grating of 1st Example. It is a state figure showing an example of operation of a dynamic diffraction grating of the 1st example. It is a state figure showing an example of operation of a dynamic diffraction grating of the 1st example. It is a state figure showing an example of operation of a dynamic diffraction grating of the 1st example. It is a state figure showing an example of operation of a dynamic diffraction grating of the 1st example. It is a state figure showing an example of operation of a dynamic diffraction grating of the 1st example. It is a timing diagram of the operation example of the dynamic diffraction grating of 1st Example. It is a block diagram of the display apparatus concerning 2nd Example of this invention. It is a timing diagram of the operation example of the dynamic diffraction grating of 2nd Example. It is a timing diagram of the operation example of the dynamic diffraction grating of 2nd Example. It is a mode table | surface of the example of an operation mode of the dynamic diffraction grating of 2nd Example. It is a mode table | surface of the example of an operation mode of the dynamic diffraction grating of 2nd Example. It is a mode table | surface of the example of an operation mode of the dynamic diffraction grating of 2nd Example.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing or each embodiment, elements having the same configuration, function, or action are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows an illumination apparatus according to a first embodiment of the present invention. As will be described in detail later, an incident beam is irradiated onto the dynamic diffraction grating 1 through PBS (5), and is split into zeroth order diffracted light reflected from the dynamic diffraction grating 1 and other nth order diffracted light. The 0th order diffracted light travels an optical path having an optical path length different from that of the nth order diffracted light, and the 0th order diffracted light and the nth order diffracted light are combined on the exit side to become an exit beam of the illumination device. Thereby, the outgoing beam includes light beams having different phases, and speckle noise of the outgoing beam can be reduced.

  In this embodiment, the incident beams R_i / G_i / B_i are beam lights obtained by converging light beams emitted from R (red) / G (green) / B (blue) laser light sources (not shown), and the wavelengths are λr / λg, respectively. A case where visible light of / λb = 630 nm / 530 nm / 450 nm and the spot size of the beam light is φ1 mm will be described.

  A dynamic diffraction grating is an optical diffraction element in which fine strip mirrors are formed in rows by MEMS technology, etc., and a voltage is applied to the strip mirrors to deform them, and the light is diffracted by the uneven shape in the arrangement direction of the strip mirrors. is there. A schematic diagram and an operation diagram of the dynamic diffraction grating 1 of this embodiment are shown in FIG. 2, FIG. 3, and FIG.

  As shown in FIG. 3, the dynamic diffraction grating 1 of the present embodiment has a reflecting surface having a mirror length (longitudinal direction) MH = 1 mm and a mirror width MW = 1 mm in accordance with the spot size φ1 of vertically incident beam light. It has. The reflecting surface is composed of 769 strip mirrors arranged at a pitch of 1.3 μm (strip mirrors m_0 to m_768).

  Displacement generators 14 for displacing individual strip mirrors are provided at both ends in the longitudinal direction of each strip mirror, and the concave and convex surfaces of the dynamic diffraction grating are formed by controlling the displacement of the strip mirrors. The displacement generation unit 14 is configured by, for example, a piezoelectric element that generates displacement by applying drive voltages ch_0 to ch_768. The piezoelectric element determines the material of the piezoelectric material, the amount of application, and the applied voltage so as to obtain the strain and change speed at which the strip mirror becomes a desired recess (depth). Of course, a displacement generating means using electrostatic force or magnetic force may be used. Further, the number of strip mirrors arranged is not limited to the above number, but may be any number that causes diffraction in reflected light described later.

  FIG. 4 shows a longitudinal section of the strip mirror. The cross section shown in FIG. 4 shows an OFF state (0% ON) in which the strip mirror has no distortion, and an ON state (50% ON) in which the recess due to the distortion of the strip mirror has a wavelength λr / 8 length (= 78.5 nm). FIG. 6 shows an ON state (100% ON) in which a recess due to distortion of a strip mirror has a wavelength λr / 4 length (= 157 nm). By applying a driving voltage (ch_0 to ch_768) so as to form a desired depression in the range of 0 to λr / 4 length for each strip mirror, irregularities on the reflecting surface of the dynamic diffraction grating 1 are formed. Of course, the driving voltage may be a voltage that becomes a dent of λr / 4 length or more.

  5 to 9 show an embodiment in which a reflecting surface is formed by a combination of drive voltages applied to each of a plurality of strip mirrors constituting a dynamic diffraction grating. The strip mirror of the dynamic diffraction grating 1 shown in FIGS. 5 to 9 is applied with two kinds of driving voltages in the above-described OFF state (0% ON) or ON state (100% ON).

  FIG. 5 shows a state in which all the strip mirrors are in the OFF state and a drive voltage is applied (hereinafter referred to as mode00). In mode00, since the concave and convex surface by the strip mirror is not formed, diffraction does not occur and all incident light is reflected (total reflection).

FIG. 8 shows a state (hereinafter referred to as mode 11) in which the drive voltage is applied to all the strip mirrors in the ON state (100% ON). In mode 11, as in the case of mode 00 in FIG. 5, the concave and convex surface by the strip mirror is not formed, so that diffraction does not occur and all incident light is reflected (total reflection). However, since the recesses due to the distortion of all the strip mirrors have the wavelength λr / 4 length (= 157 nm), the optical path length to the screen is longer by the wavelength λr / 2 than mode00. Shows a state (hereinafter referred to as mode01 and mode10) in which the strip mirror is alternately applied with an OFF state and an ON state (100% ON). In mode01 and mode10, a concave / convex surface with a wavelength λr / 4 length (= 157 nm) is formed at a pitch of 2.6 μm by a strip mirror.

Due to the uneven surface, diffracted light is generated. Here, the relationship between the diffraction angle θ and the wavelength λ of the + 1st order light and the −1st order light and the pitch D of the diffraction grating is defined as follows.
sinθ = λ / D (Equation 1)
In the present embodiment in which the pitch D = 1.3 μm, the diffraction angles θr / θg / θb of the R / G / B light beams are 14.023 degrees / 11.762 degrees / 9.967 degrees, respectively.

  In mode01 and mode10, the dent amount can be changed by increasing or decreasing the drive voltages ch_0 to ch_768 (for example, a drive voltage of 50% ON). Thereby, the light quantity of diffracted light is controllable. The reflection amount of the diffracted light is maximized by the λr / 4 long recess.

  In this embodiment, the concave / convex period is formed by two strip mirrors, but the concave / convex period may be formed by a smaller pitch and by two more strip mirrors. Thereby, the pitch D of Formula 1 can be adjusted, and the increase / decrease of the diffraction angles θr / θg / θb can be adjusted.

  In the above embodiment, the reflection surface of the dynamic diffraction grating is uniformly uneven, but the reflection surface of the dynamic diffraction grating 1 is divided into four regions as shown in FIG. You may make it make an area | region the state of mode00, mode01, mode10, and mode11. Even in this case, the coherency of the beam light becomes weak, and there is an effect of reducing speckle noise.

  Needless to say, the effect of the speckle noise reduction of the present invention is not limited to the combination of the states of mode00 to mode11 of the present embodiment.

  Next, an example of the driving timing of the dynamic diffraction grating will be described with reference to the timing chart of FIG. The modulation mode generation unit 2 in FIG. 1 includes a setting condition μCOM that predetermines a combination method of a desired state of the dynamic diffraction grating 1, for example, the states (mode 00 to mode 11) shown in FIGS. The scan address scan_add that changes at regular intervals or discontinuously in time series is obtained, the state (mode00 to mode11) corresponding to the scan address scan_add and the dent amount of the strip mirror are determined, and the operation mode mode_ch and dent of each strip mirror Generate quantity amp_ch. The drive unit 3 determines the drive amount of each strip mirror from the operation mode mode_ch and the dent amount amp_ch, generates drive voltages ch0 to ch768, and drives the dynamic diffraction grating 1.

  As shown in FIG. 10, in this embodiment, for each horizontal scanning line (1H) of the beam light, the state of the dynamic diffraction grating (mode00 to mode11) and the recess amount of the strip mirror (100% ON, 50% ON). Are changed sequentially. Since the coherency of the beam light varies every horizontal scanning line time, speckle noise can be reduced. The change in the state of the dynamic diffraction grating, the change in the recess amount of the strip mirror, and the adjustment interval are not limited to this example.

Next, the optical path configuration of the beam light of the spectroscopic / synthesis unit 13 of the present embodiment will be described in detail.
An incident beam R_i / G_i / B_i in a state aligned with S-polarized light is incident on the spectroscopic / synthesizing unit 13, reflected 90 degrees by PBS (5), and phase delayed by the λ / 4 phase difference plate 4, It is perpendicularly incident on the reflecting surface of the dynamic diffraction grating 1. The dynamic diffraction grating 1 is driven as described above and reflects diffracted light.

  Of the reflected diffracted light, the 0th-order light beams R_0 / G_0 / B_0 and R_0d / G_0d / B_0d are regularly reflected in the same direction as the incident light and become P-polarized light components by the λ / 4 phase difference plate 4 PBS (5) , The optical path direction is adjusted by mirrors 6, 7, and 8, an S-polarized light component is formed by λ / 2 phase difference plate 9, is incident on PBS (12), is reflected by 90 degrees, and is one of outgoing beams R_o / G_o / B_o Part.

  Here, the 0th-order light beams R_0 / G_0 / B_0 and R_0d / G_0d / B_0d are reflected light from the strip mirror when the dynamic diffraction grating 1 described above is in the state of mode00 or mode11, and the optical paths thereof. It is a 0th-order beam of different length.

  On the other hand, the + 1st order light beam R_1p / G_1p / B_1p and the −1st order light beam R_1m / G_1m / B_1m diffracted and reflected by the dynamic diffraction grating 1 at a predetermined diffraction angle are incident on the condensing unit 10 and then combined. The image is re-imaged on the interference unit 11, and beams R_1p / G_1p / B_1p and R_1m / G_1m / B_1m are multiplexed by a multiplexing interferometer.

  The PBS (5) and the mirror 6 have outer dimensions within the diffraction angle θ of the + 1st order light and the −1st order light defined by (Equation 1) so as not to interfere with the ± 1st order diffracted light. Similarly, the outer shape of the light collecting unit 10 is also defined by the diffraction angle θ.

  Here, as a specific configuration of the light collecting unit 10 and the multiplexing interference unit 11, for example, means disclosed in Japanese Patent Application Laid-Open No. 2007-263711 may be used.

  The ± first-order diffracted light combined with the P-polarized light component passes through the PBS (12) and becomes a part of the outgoing beam R_o / G_o / B_o (binding). At this time, the position of the structure is adjusted so that the beam spot matches the optical path. In the embodiment, the light concentrator 10 excludes light components of ± 2nd order diffracted light or higher.

  With the control and operation described above, the outgoing beams R_o / G_o / B_o are mixed with P-polarized light, S-polarized light, and S-polarized light components with different optical path lengths, and their distribution is in the area direction (division of beam light) and time series. It is something to change.

  In this embodiment, attention is paid to the 0th order and ± 1st order diffracted light. However, by adjusting the condensing unit 10, even the 2nd order or higher order diffracted light can be processed in the same manner as described above, and the utilization efficiency of the light flux is also improved. improves.

  When the beam spot size is φ1, PBS (5) is set to the minimum size, the distance from the dynamic diffraction grating 1 to the light converging part 10 is minimized, and ± 1st order diffracted light is not interfered. By selecting the strip mirror pitch D = 1.3 μm, the spectroscopic / multiplexing unit 13 can be realized with a low profile and a small size. Of course, it is not limited to this as long as it is optimized (for example, a condition for minimizing the structure) according to the selection of the pitch D according to the spot size of the light beam, the wavelength to be used, the optical member and the arrangement.

  Although the strip mirror is shown in the case of changing in the dent direction, the same applies to the convex direction.

  The dynamic diffraction grating 1 may be configured by a plurality of diffraction modes (grating patterns) within an area, and the dynamic diffraction grating 1 may be vibrated by the scan address scan_add.

  According to the present invention, a small and low-profile mechanism is possible, and beam shape maintenance and speckle reduction are possible.

  Next, an embodiment of the illumination device shown in the first embodiment is shown in a display device in which a laser beam is applied to a MEMS mirror that swings about two axes, and the reflected light is raster-scanned and projected on an object. 11, 12, 13, 14 and 15.

  In this embodiment, a description will be given of a case where a laser beam source and a laser light source that is easy to modulate light quantity at high speed is used as the light source. Of course, a coherent light source may be used together with an optical component for condensing in a beam shape or a light amount modulating component. In this embodiment, the control / drive method of the oscillating mirrors 21 and 22 is not mentioned, but the control / drive of the oscillating mirrors 21 and 22 is performed by electromagnetic induction, piezoelectric drive, electrostatic drive, etc. Any of them may be used so long as the image is oscillated, and the image is reproduced by a process similar to that of known control and drive, and detailed description is avoided.

  For the sake of explanation, it is a video signal with a resolution of XGA (1024 × 768 pixels), and the oscillating mirrors 21 and 22 have a size of φL = 1.2 mm and oscillate in one axis direction with a resonance period of 30 kHz (H oscillation). To be operated). Oscillation is caused by the 60 Hz low-speed oscillation signal v_drive of the mirror drive unit 20 and the 30 kHz high-speed oscillation signal h_drive. The swing angle is adjusted by this swing signal.

  The address generation unit 18 receives the frame start signal VM_sync of the video signal, the line start signal HM_sync, the pixel clock (60 MHz) of the video signal, and the scanning address scan_add from the swing position signal H / V_sensor detected by the mirror drive unit 20. Generate.

  On the other hand, when the 60 kHz horizontal synchronization signal H_sync, the 60 Hz vertical synchronization signal V_sync and the video signal 17 are received at the input terminals 15, 16 and 17, but the frame start signal VM_sync and the line start signal HM_sync are asynchronous, the RAM 23 is Timing conversion may be performed.

  The signal modulating unit 24 and the light source driving unit 25 modulate and drive the light emission amount of the RGB laser light source 26r / 26g / 26b with the video signal for each pixel read from the input video signal video based on VM_sync and HM_sync. The light beam is condensed by the collimator lens 27 at the wavelengths λr = 630 nm, λg = 530 nm, and λb = 450 nm of the RGB laser light source 26r / 26g / 26b, and is made to be in a state where it is aligned with parallel beam light of φ1 mm diameter and S-polarized light.

  The RGB laser light is further multiplexed on the same axis by the dichroic mirrors 28 and 29 to obtain parallel beam light, which is used as the incident beam R_i / G_i / B_i in the first embodiment. The spectroscopic / multiplexing unit 13 performs the operation described in the first embodiment and emits an outgoing beam R_o / G_o / B_o. The outgoing beams R_o / G_o / B_o are reflected and scanned by the biaxial oscillating mirrors 21 and 22, and the raster scan locus 30 is projected and displayed on the display area 31.

  When operating in the configuration described above, the combination method of the states (mode00 to mode11) shown in FIGS. 5 to 9 and the setting condition μCOM for predetermining the dent amount are, for example, μCOM = Type_0_100 and FIG. 12 is the operation shown in the first half of the timing diagram. Similarly, if μCOM = Type_1_50 and FIG. 15 is used, the operation shown in the second half of FIG. 12 is performed.

  For example, FIG. 14 is a table in which the effective display area is time-divided. In the column direction, one horizontal line is time-divided into 8 blocks, the row direction indicates the line number and frame number 0, and the beam light raster scan is performed. The mode (the last two digits of mode00 to mode11) at the position (time position) is clearly indicated.

  For example, if frame number = 0, line number = 0 (ad_0_000), and 1 horizontal line is 0 block (0), it is referred to as mode_00 and the timing diagram of FIG. On the other hand, if μCOM = Type_1_50 in the second half of the timing diagram of FIG. 12, for example, frame number = 0, line number = 0 (ad_0_000), and if 1 horizontal line is 0 block (0), refer to mode_11 and amplitude 50% As shown in the timing chart of FIG. Similarly, if μCOM = Type_1_100 and the table of FIG. 16 is used, the timing diagram of FIG. 12 is obtained.

  In this way, by setting various operating conditions with the setting condition μCOM and the mode table shown in FIGS. 13, 14, and 15 as an example, the intensity of the light beam is modulated according to the raster position, and at the same time, the mirror driving cycle and The dynamic diffraction grating is controlled so that the polarization and the optical path length are different or smoothed in terms of time and area on the projection display surface in the modulation period of the intensity of the beam light.

  Here, an example in which the effective display area is time-divided is shown. However, any division or mode corresponding to the response speed of the strip mirror may be used, and at each scanning position of the raster scan, the beam light area is divided. What is necessary is just to operate so that the mixture of modes and the state of light beams adjacent in the time direction or area direction (polarization direction and optical path length difference and their distribution) are mixed. Further, the mode may be switched at a speed of 16.67 nsec (pixel clock 60 MHz) for displaying one pixel by raster scanning.

  According to the present invention, in a laser scanning type display device, a small and low-profile mechanism is possible, and by maintaining the beam shape and reducing speckles, a high resolution and smooth image quality are possible.

  In addition, the beam light is shown in the case of a single wavelength for each color (single mode). However, even in a laser light source (multimode) having a wavelength width, the diffraction angle and the combined portion are not limited at any wavelength. Corresponding.

  Also, the strip mirror is shown as being arranged independently. However, if the strip mirror is arranged on a uniaxial or biaxial oscillating mirror, modulation of the optical path length, 0th order light and ± 1st order diffracted light are used. Even if the raster scan position is different due to the shift of the optical axis, the same effect as this embodiment can be obtained by displaying the same image in the same display position by displaying the image rearranged in accordance with the display position. It is done.

  R_i / G_i / B_i ... incident beam, R_o / G_o / B_o ... outgoing beam, 1 ... dynamic diffraction grating, 2 ... modulation mode generator, 3 ... driver, 4 ... λ / 4 phase difference plate, 5, 12 ... PBS, 6, 7, 8 ... mirror, 9 ... λ / 2 phase difference plate, 10 ... condensing unit, 11 ... multiplexing interference unit, 13 ... spectroscopic / multiplexing unit, 14 ... displacement generating unit, 15, 16 ... Sync signal input terminals H_sync / V_sync, 17 ... Video signal input terminal, 18 ... Address generation unit, 19 ... Drive condition setting unit, 20 ... Mirror drive unit, 21 ... Horizontal oscillating mirror, 22 ... Vertical oscillating unit, 23 ... RAM, 24 ... signal modulation unit, 25 ... light source driving unit, 26r / g / b ... light source, 27 ... condensing lens, 28, 29 ... dichroic mirror, 30 ... raster scan locus, 31 ... display area.

Claims (12)

A beam light illumination device for a display device that scans and displays a coherent beam light,
A reflection type dynamic diffraction grating that receives the light beam having the coherent property and reflects the diffracted light by changing the surface shape of the reflection surface over time;
A condensing unit that condenses and images n-order diffracted light (n is an integer other than 0) of the diffracted light reflected by the dynamic diffraction grating;
A combining unit that combines the nth order diffracted light collected by the light collecting unit and the 0th order diffracted light of the diffracted light reflected by the dynamic diffraction grating as an output beam;
An illumination apparatus, wherein an image is displayed by scanning the outgoing beam formed by the multiplexing unit. The lighting device according to claim 1.
The dynamic diffraction grating comprises a plurality of strip mirrors having a predetermined width arranged in one direction,
The strip mirror is movable in the incident direction of the beam light at a predetermined interval to form an uneven diffraction surface on a plane perpendicular to the incident direction of the beam light. The lighting device according to claim 2,
There are multiple drive modes to determine the movable strip mirror among the multiple strip mirrors,
Each of the strip mirrors is movable based on different driving modes at different times. The lighting device according to claim 3.
The strip mirror is divided into a group of a plurality of strip mirrors,
The strip mirror is movable for each group based on different driving modes. In the illuminating device in any one of Claim 3 or 4,
The driving mode includes the case where the same movable amount is deformed between adjacent strip mirrors,
An illumination device characterized in that the optical path length of the beam light changes with time. In the illuminating device as described in any one of Claims 2-5,
The strip mirror can be moved in the incident direction of the beam light by a plurality of movable amounts,
The strip mirror is movable with different movable amounts at different times. In the illuminating device as described in any one of Claims 1-6,
The dynamic diffraction grating moves the strip mirror at a predetermined period. In the illuminating device as described in any one of Claims 1-7,
An illumination device, wherein an optical path of the 0th-order diffracted light and an optical path of the nth-order diffracted light (n is an integer other than 0) are different. The lighting device according to claim 8, further comprising:
A first PBS that receives the coherent beam light aligned with the S-polarized light and reflects it by 90 degrees, and transmits the 0th-order diffracted light from the dynamic diffraction grating;
A λ / 4 plate that delays the phase of transmitted light;
A plurality of reflecting mirrors for guiding the 0th-order diffracted light that has passed through the first PBS to the multiplexing unit, and
The multiplexing unit is
A multiplexing interference unit for multiplexing coherent light;
A λ / 2 plate that converts transmitted light into S-polarized light,
A second PBS that transmits nth order diffracted light from the dynamic diffraction grating and reflects zeroth order diffracted light from the dynamic diffraction grating,
The coherent beam light aligned with S-polarized light is applied to the dynamic diffraction grating via the first PBS and the λ / 4 plate,
The 0th-order diffracted light diffracted and reflected by the dynamic diffraction grating passes through the λ / 4 plate and the first PBS, is guided by the plurality of reflecting mirrors, and is S-polarized by the λ / 2 plate. ,
The nth-order diffracted light diffracted and reflected by the dynamic diffraction grating with a diffraction angle passes through the λ / 4 plate, and is imaged on the multiplexing interference unit by the condensing unit.
In the second PBS, the 0th-order diffracted light S-polarized by the λ / 2 plate is reflected by 90 degrees, and the nth-order diffracted light from the combined interference unit is transmitted. In a display device that displays by scanning a coherent beam,
A laser light source that emits a coherent beam modulated with video information;
A scanning mirror that raster-scans the beam light on the object by reflecting the beam light of the laser light source with a mirror that swings in one or two axes;
A coherence conversion unit that collects the 0th-order diffracted light and the nth-order diffracted light (n is an integer other than 0) that is incident on the coherent beam and emits the incoherent beam;
A display device that performs display by scanning the light beam converted by the coherence conversion unit with the scanning mirror. The display device according to claim 10, wherein the coherence conversion unit includes:
A reflection type dynamic diffraction grating that receives the light beam having the coherent property and reflects the diffracted light by changing the surface shape of the reflection surface over time;
A condensing unit that condenses n-order diffracted light (n is an integer other than 0) of the diffracted light reflected by the dynamic diffraction grating;
And a combining unit that combines the nth-order diffracted light collected by the condensing unit and the 0th-order diffracted light of the diffracted light reflected by the dynamic diffraction grating as an output beam. apparatus. The display device according to claim 11,
The dynamic diffraction grating comprises a plurality of strip mirrors having a predetermined width arranged in one direction,
The strip mirror is movable at predetermined intervals in the incident direction of the beam light for every horizontal scanning time of the scanning mirror, and forms a concave and convex diffractive surface on a plane perpendicular to the incident direction of the beam light. Display device.

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