JP2009229596A - Image display apparatus - Google Patents

Abstract

An image display apparatus having high light utilization efficiency and capable of reliably suppressing speckle noise.
Light sources 10R, 10G, 10B for emitting laser light, scanning means 30 for scanning laser light emitted from the light sources 10R, 10G, 10B toward a projection surface 50, and light sources 10R, 10G, And a wavelength changing unit 40 that temporally changes the output wavelength of the laser light emitted from 10B.
[Selection] Figure 1

Description

  The present invention relates to an image display device.

In recent years, with increasing demand for miniaturization of projectors, projectors using laser light sources have been developed with the increase in output of semiconductor lasers and the appearance of blue semiconductor lasers. This type of projector can be used as a next-generation display device because the wavelength range of the light source is narrow, so the color reproduction range can be sufficiently widened, and downsizing and reduction of components are possible. It has sex.
However, when performing display with image light in a projector using a laser light source, so-called scintillation in which bright spots and dark spots are distributed in a striped pattern or a spotted pattern due to light interference caused by a scatterer such as a screen, Alternatively, a phenomenon called speckle noise may occur.

  Speckle noise causes an adverse effect such as giving an observer a glare and giving an uncomfortable feeling when viewing an image. In particular, since laser light is highly coherent, speckle noise is likely to occur. However, even in the case of a lamp light source, in recent years, the coherence has been increased by shortening the arc, and a technique for removing speckle noise is important. Therefore, a technique for reducing speckle noise has been proposed (see, for example, Patent Document 1).

The laser beam generator described in Patent Document 1 includes a laser light source, a phase modulation unit, and a wavelength conversion unit. Laser light emitted from the laser light source undergoes phase modulation by the phase modulation means. Then, the light subjected to the phase modulation is converted into another wavelength by the wavelength converting means. As a result, the spectral width of the light emitted from the wavelength conversion means is sufficiently widened, so that speckle noise can be reduced.
JP 9-121069 A

  However, since the laser light generating device described in Patent Document 1 uses the wavelength converting unit, the light is absorbed by the wavelength converting unit, and the light use efficiency decreases. Further, it is difficult to sufficiently reduce speckle noise because the speckle pattern does not change only by widening the spectrum width of the light by the wavelength converting means.

  SUMMARY An advantage of some aspects of the invention is that it provides an image display device that has high light utilization efficiency and can reliably suppress speckle noise.

In order to achieve the above object, the present invention provides the following means.
The image display device of the present invention includes a light source that emits laser light, a scanning unit that scans the laser light emitted from the light source toward a projection surface, and an output wavelength of the laser light emitted from the light source. And a wavelength changing means for changing the frequency.

In the image display device according to the present invention, the light emitted from the light source is scanned by the scanning unit to form an image on the projection surface. At this time, the state of the light source is changed by the wavelength changing means, and the output wavelength of the laser light emitted from the light source is temporally changed. Thereby, the speckle pattern projected on the projection surface changes with time. As a result, the speckle pattern is integrated and averaged within the afterimage time of the human eye, and speckle noise in the image projected on the projection surface is suppressed. Therefore, the viewer can view the image well and fatigue is reduced. That is, since the state of the light source is changed by the wavelength changing unit, it is possible to form a clear image on the projection surface without reducing the light use efficiency.
Furthermore, since the speckle pattern does not change with time because the spectrum width has been widened in the past, speckle noise cannot be reduced sufficiently. However, in the present invention, the speckle pattern changes with time. It is possible to reliably suppress speckle noise.

  In the image display device of the present invention, it is preferable that the wavelength changing unit is a refractive index changing unit that changes the refractive index of the light source with time.

  In the image display device according to the present invention, since the resonator length in the light source changes by changing the refractive index of the light source with time by the refractive index changing means, the output wavelength of the laser light emitted from the light source changes over time. Changes. That is, since the speckle pattern changes with time, it is possible to reliably suppress speckle noise.

  In the image display device of the present invention, it is preferable that the wavelength changing unit is a temperature changing unit that changes the temperature of the light source with time.

  In the image display device according to the present invention, the resonator length in the light source is changed by temporally changing the temperature of the light source by the temperature changing means, so that the output wavelength of the laser light emitted from the light source is temporally changed. Change. That is, since the speckle pattern changes with time, it is possible to reliably suppress speckle noise.

  It is preferable that the wavelength changing unit is a pressure changing unit that temporally changes the pressure applied to the light source.

  In the image display device according to the present invention, since the resonator length in the light source is changed by temporally changing the pressure applied to the light source by the pressure changing means, the output wavelength of the laser light emitted from the light source is temporal. To change. That is, since the speckle pattern changes with time, it is possible to reliably suppress speckle noise.

  In the image display device of the present invention, the light source is different from the first reflecting portion provided on the emission end face side from which the laser light is emitted, and a part of the incident light is different from the first reflecting portion. A second reflecting portion that transmits light in the direction and reflects the remaining light toward the first reflecting portion, and the wavelength changing unit directs the light transmitted through the second reflecting portion toward the exit end face. A reflecting member to be reflected, has light transparency, and is disposed on an optical path between the second reflecting portion and the reflecting member, and changes an optical distance between the first reflecting portion and the reflecting member. It is preferable to have the optical member to be made and the second reflecting portion.

  In the image display device according to the present invention, the light transmitted through the second reflecting portion enters the optical member, is reflected by the reflecting member, and passes through the optical element again. And the laser beam which passed the 2nd reflection part and the 1st reflection part is inject | emitted from the emission end surface. At this time, for example, since the optical distance between the first reflecting portion and the reflecting member is changed by swinging the optical member, the resonator length in the light source is changed, so that the light emitted from the light source is changed. Output wavelength changes with time. That is, since the speckle pattern changes with time, it is possible to reliably suppress speckle noise.

  In the image display device of the present invention, it is preferable that the change amount of the output wavelength of the laser light emitted from the light source has a color difference of 5/1000 or less.

  In the image display device according to the present invention, the amount of change in the output wavelength of the laser light emitted from the light source is within a color difference range of 5/1000 or less. Since it is difficult to identify the color with the eyes, it is possible to reliably suppress speckle noise while displaying a clear image.

  Further, in the image display device of the present invention, the wavelength changing means is configured so that the frequency at which the output wavelength of the laser light emitted from the light source changes and the frequency at which the scanning means scans the laser light are not synchronized. It is preferable to periodically change the output wavelength of the laser light.

Here, if the frequency at which the output wavelength of the laser light emitted from the light source changes and the frequency at which the scanning means scans the laser light are synchronized, the same speckle pattern is integrated and averaged. Pattern cannot be reduced.
Therefore, in the image display device according to the present invention, the wavelength changing means changes the frequency at which the output wavelength of the laser light changes and the frequency at which the laser light is scanned by the scanning means so as not to synchronize with each other. Since the different speckle patterns are temporally integrated in the predetermined irradiation area in FIG. 1, it is possible to reliably suppress speckle noise. Further, since the wavelength changing means periodically changes the output wavelength of the laser light, it becomes easy to control the state of the light source in terms of time.

  In the image display device of the present invention, it is preferable that the wavelength changing unit aperiodically changes the output wavelength of the laser light emitted from the light source.

  In the image display apparatus according to the present invention, since the wavelength changing unit changes the output wavelength of the laser light aperiodically, the pattern for changing the output wavelength of the laser light is surely set to the frequency at which the scanning unit scans the laser light. It is possible to change so as not to synchronize. Therefore, speckle noise can be suppressed more reliably.

  In the image display device of the present invention, the light source includes a red light source that emits red laser light, a green light source that emits green laser light, and a blue light source that emits blue laser light, and the wavelength changing unit. Is preferably provided at least in the green light source and temporally changes the output wavelength of the green laser light emitted from the green light source.

  In the image display device according to the present invention, a bright image is displayed on the projection surface by temporally changing the output wavelength of the green laser light that contributes most to the brightness of the image displayed on the projection surface. It becomes possible.

  In the image display device of the present invention, the wavelength changing means is provided in each of the red light source, the green light source, and the blue light source, and the red laser emitted from the red light source, the green light source, and the blue light source. It is preferable to change the output wavelengths of light, green laser light, and blue laser light with time.

  In the image display device according to the present invention, the output wavelengths of the red laser light, the green laser light, and the blue laser light emitted from the red light source, the green light source, and the blue light source are changed with time, thereby more effectively. Speckle noise can be reduced.

  Embodiments of an image display apparatus according to the present invention will be described below with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

[First Embodiment]
FIG. 1 is a perspective view showing the entire image display device, FIG. 2 is a plan view showing a MEMS mirror, and FIG. 3 is a cross-sectional view showing a light source.
As shown in FIG. 1, the image display device 1 according to the present embodiment includes a light source device 10, a cross dichroic prism 20, a MEMS mirror (scanning unit) 30, and a temperature adjustment unit (wavelength changing unit, temperature changing unit). 40 is a device that displays an image by scanning the laser beam emitted from the light source device 10 by the MEMS mirror 30 toward the screen 50.

The light source device 10 includes a red light source (light source) 10R having an emitter (light emitting unit) 11 that emits red laser light, a green light source (light source) 10G having an emitter 11 that emits green laser light, and blue laser light. And a blue light source (light source) 10B having an emitter 11 for emission.
The red light source 10R is a semiconductor laser (LD) that emits red laser light having a center wavelength of 630 nm, and the blue light source 10B is a semiconductor laser (LD) that emits blue laser light having a center wavelength of 430 nm. The green light source 10G is configured by a DPSS (Diode Pomping Solid State) laser, and an infrared laser beam is converted into a green laser beam having a center wavelength of 540 nm by a wavelength conversion element (not shown).
The cross dichroic prism 20 combines red laser light, green laser light, and blue laser light emitted from the light sources 10R, 10G, and 10B.

As shown in FIG. 1, the MEMS mirror 30 scans the laser beam synthesized by the cross dichroic prism 20 toward the screen 50, and as shown in FIG. 2, the mirror unit 31 and beams 32a and 32b. And a resonance type mirror including a first substrate 33, beams 34 a and 34 b, and a second substrate 35.
The mirror unit 31 is provided in the center of the MEMS mirror 30 and reflects incident laser light to the screen 50. The beams 32 a and 32 b are provided on both sides of the mirror portion 31 so as to extend in the horizontal direction (X-axis direction) of the screen 50.
The first substrate 33 has a frame shape surrounding the mirror portion 31 and is connected to the beams 32a and 32b. The beams 34 a and 34 b are provided on both sides of the first substrate 33 so as to extend in the vertical direction (Y-axis direction) of the screen 50.
The second substrate 35 has a frame shape surrounding the first substrate 33 and is connected to the beams 34a and 34b.
As a result, the mirror unit 31 can vibrate with respect to the first substrate 33 with the beams 32 a and 32 b as vibration axes, and the first substrate 33 vibrates the beams 34 a and 34 b with respect to the second substrate 35. Oscillating motion is possible as an axis. Therefore, the MEMS mirror 30 can vibrate in the x-axis and y-axis directions, that is, can scan the laser beam in the horizontal direction and the vertical direction of the screen 50.
Therefore, by vibrating the mirror unit 31 around the X axis by the beams 32a and 32b, the vertical resonance frequency of the mirror unit 31 changes, and the first substrate 33 is vibrated around the Y axis by the beams 34a and 34b. By doing so, the horizontal resonance frequency of the first substrate 33 changes.
Further, the laser light emitted from the light source device 10 is scanned from the upper end 50a to the lower end 50b of the screen 50 by the mirror unit 31, as shown in FIG. 1, and from the left end 50c side of the screen 50 by the first substrate 33. Scan to the right end 50d side.

As shown in FIG. 3, the temperature adjusting unit 40 is provided on each of the back surfaces 10b opposite to the emission end surface 10a on which the emitters 11 of the light sources 10R, 10G, and 10B are formed. The temperature adjustment unit 40 includes a temperature sensor 41 and a Peltier element 42.
The temperature sensor 41 measures the temperature of the light sources 10R, 10G, and 10B. The Peltier element 42 heats or cools the light sources 10R, 10G, and 10B. The light sources 10R, 10G, and 10B expand by heating and contract by cooling to change the refractive index. Corresponding to this refractive index, the resonator length inside the light sources 10R, 10G, and 10B changes. Further, the Peltier element 42 is configured so that the output wavelength of the laser light emitted from the light sources 10R, 10G, and 10B changes with time according to the temperature of the light sources 10R, 10G, and 10B detected by the temperature sensor 41. The light sources 10R, 10G, and 10B are heated or cooled.

  Further, the temperatures of the light sources 10R, 10G, and 10B are controlled by the temperature adjusting unit 40 so that the temperatures of the light sources 10R, 10G, and 10B change with periodicity. Then, the temperature adjustment unit 40 adjusts the temperatures of the light sources 10R, 10G, and 10B so that the frequency at which the temperature changes does not synchronize with the frequency at which the laser beam is scanned by the MEMS mirror 30.

  The change amount of the output wavelength of the laser light emitted from the light sources 10R, 10G, and 10B is within a range where the color difference is 5/1000 or less, that is, the wavelength change amount of the red laser light and the blue laser light is within ± 2 nm. The wavelength change amount of the green laser light is in the range of ± 1.5 nm or less. Therefore, the temperature adjustment unit 40 periodically changes the output wavelength of the laser light within the range of ± 2 nm or less for the red light source 10R and the blue light source 10B, and the laser light for the green light source 10G within the range of ± 1.5 nm or less. The output wavelength of is periodically changed. However, the range of the wavelength change amount of the laser light is only an example.

Next, a method for displaying an image on the screen 50 by the image display device 1 of the present embodiment having the above configuration will be described.
First, red laser light, green laser light, and blue laser light are emitted from the light sources 10R, 10G, and 10B based on the video signal. The red laser light, green laser light, and blue laser light emitted from the light sources 10R, 10G, and 10B are combined in the cross dichroic prism 20 and then enter the MEMS mirror 30.
The laser light incident on the MEMS mirror 30 is scanned (vertically) from the upper end 50a to the lower end 50b or from the lower end 50b to the upper end 50a of the screen 50 by vibration around the X axis of the mirror portion 31 of the MEMS mirror 30. The Further, the screen is scanned from the left end 50c of the screen 50 toward the right end 50d (horizontal direction) by the vibration of the first substrate 33 around the Y axis. In this way, an image is displayed on the screen 50.
Here, since the temperature of each of the light sources 10R, 10G, and 10B is changed by the temperature adjustment unit 40, laser beams having different output wavelengths are periodically emitted from the light sources 10R, 10G, and 10B.

Next, a change in the output wavelength of the laser beam scanned on the screen 50 will be specifically described.
For example, the output wavelength of the red laser light that irradiates a specific pixel L1 (shown in FIG. 1) on the screen 50 in the first frame is 630 nm, and the output of the red laser light that irradiates the pixel L1 on the screen 50 in the second frame. The temperatures of the light sources 10R, 10G, and 10B are controlled so that the wavelength is 631 nm and the output wavelength of the red laser light that illuminates the pixel L1 on the screen 50 in the third frame is 630 nm. In this way, the output wavelength of the laser light that irradiates the pixel L1 changes every frame, and the red laser light is scanned on the screen 50.
Similarly, the output wavelengths of the laser beams emitted from the green light source 10G and the blue light source 10B are emitted with green and blue laser beams having an output wavelength changed by 1 nm for each frame and scanned on the screen 50.
The “pixel” referred to here is an irradiation area on the screen 50 corresponding to one pixel which is the minimum unit constituting the projection image.

In the image display device 1 according to the present embodiment, the output wavelength of the laser light emitted from each of the light sources 10R, 10G, and 10B changes with time, so the speckle pattern projected on the screen 50 changes with time. . As a result, the speckle pattern is integrated and averaged within the afterimage time of the human eye, and speckle noise in the image projected on the screen 50 is suppressed. Therefore, the viewer can view the image well and fatigue is reduced.
That is, since the speckle pattern is changed by changing the resonator length of each of the light sources 10R, 10G, and 10B by the temperature adjustment unit 40, a clear image can be displayed on the screen 50 without reducing the light use efficiency. It becomes possible to form.
Furthermore, since the speckle pattern does not change with time because the spectrum width has been widened in the past, speckle noise cannot be reduced sufficiently. However, in the present invention, the speckle pattern changes with time. It is possible to reliably suppress speckle noise.
That is, the image display apparatus 1 according to the present embodiment has high light utilization efficiency and can surely suppress speckle noise.

In addition, since the amount of change in the output wavelength of the laser light emitted from the light sources 10R, 10G, and 10B is in the range of 5/1000 or less, even if the output wavelength of the laser light changes with time, Since identification is difficult with the eyes, it is possible to reliably suppress speckle noise while displaying a clear image.
In addition, the temperature adjusting unit 40 changes the temperature of the light sources 10R, 10G, and 10B so that the frequency at which the output wavelength of the laser light changes and the frequency at which the laser beam is scanned by the MEMS mirror 30 are not synchronized. Since different speckle patterns are integrated over time, it is possible to reliably suppress speckle noise. Further, since the temperature adjustment unit 40 periodically changes the output wavelength of the laser light, the temperature control of each of the light sources 10R, 10G, and 10B is simplified.
Furthermore, since the temperature adjustment unit 40 is provided in each of the red light source 10R, the green light source 10G, and the blue light source 10B, the output wavelengths of the emitted red laser light, green laser light, and blue laser light are temporally changed. By changing, speckle noise can be reduced more effectively.

In the present embodiment, the temperature adjusting unit 40 is used as the wavelength changing unit. However, the temperature adjusting unit 40 is not limited to this. For example, a refractive index changing unit that changes the refractive index of each of the light sources 10R, 10G, and 10B with time is used. It may be used. In this configuration, the output wavelength of the laser light emitted from the light sources 10R, 10G, and 10B is changed temporally by changing the current applied to the light sources 10R, 10G, and 10B with the refractive index changing means. Is possible.
Further, although the temperature adjustment unit 40 controls the temperatures of the light sources 10R, 10G, and 10B to change with periodicity, the output wavelength of the laser light may be changed aperiodically. That is, when the temperature adjustment unit 40 changes the output wavelength of the laser light aperiodically, the pattern in which the output wavelength of the laser light changes and the frequency at which the MEMS mirror 30 scans the laser light are not reliably synchronized. . Therefore, speckle noise can be suppressed more reliably.

Furthermore, although the temperature adjustment unit 40 is configured to be provided in each of the light sources 10R, 10G, and 10B, for example, the temperature adjustment unit 40 may be configured to include only the green light source 10G. With this configuration, a bright image can be displayed on the screen 50 by temporally changing the output wavelength of the green laser light that contributes most to the brightness of the image projected on the screen 50.
Further, although the output wavelength of the laser beam that irradiates the pixel L1 is changed for each frame, the timing for changing the output wavelength of the laser beam may be two or more frames. Further, although the MEMS mirror 30 is used as the scanning means, the present invention is not limited to this.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described with reference to FIG. In the drawings of the respective embodiments described below, portions having the same configuration as those of the image display device 1 according to the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
The image display apparatus according to the present embodiment differs from the first embodiment in the configuration of the wavelength changing means. Other configurations are the same as those of the first embodiment. FIG. 4 is a view of the light sources 10R, 10G, and 10B as viewed from the emission end face 10a side.

In the present embodiment, as shown in FIG. 4, a pressure changing section (pressure changing means) 60 that changes the pressure applied to the light sources 10R, 10G, and 10B with time is used as the wavelength changing means.
The pressure changing unit 60 includes an insulator 12a and an electrode 13a in order on the end face 10c of each of the light sources 10R, 10G, and 10B, and similarly includes an insulator 12b and an electrode 13b on the end face 10d. A power source E is electrically connected to the electrode 13a and the electrode 13b. When the power source E applies a voltage between the electrode 13a and the electrode 13b, the electrode 13a and the electrode 13b are attracted by the electrostatic force. Due to this electrostatic force, pressure is applied to the light sources 10R, 10G, and 10B, so that the internal resonator length changes.
Further, the output wavelength of the laser light emitted from each of the light sources 10R, 10G, and 10B is determined by the voltage value applied between the electrode 13a and the electrode 13b by the power source E, and according to the cycle in which the voltage value changes, The frequency of the output wavelength of the laser light is determined.

In the image display apparatus according to the present embodiment, since the pressure is applied to the light sources 10R, 10G, and 10B by the pressure changing unit 60, the internal resonator length changes, so the voltage applied to the electrodes 13a and 13b is temporally changed. By changing it, it becomes possible to temporally change the output wavelength of the emitted laser light. Therefore, since the speckle pattern projected on the screen 50 changes with time, the speckle pattern is integrated and averaged within the afterimage time of the human eye, and speckle noise can be suppressed.
Further, the voltage applied between the electrodes 13a and 13b is not periodic, but by applying a non-periodic voltage, the output wavelength of the laser light emitted from the light sources 10R, 10G, and 10B is aperiodic. It becomes possible to change to. That is, by controlling the voltage applied between the electrode 13a and the electrode 13b, the output wavelength of the laser beam can be changed aperiodically by a simple method.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described with reference to FIG.
The image display apparatus according to the present embodiment differs from the first embodiment in the configuration of the wavelength changing means. Other configurations are the same as those of the first embodiment. FIG. 5 is a side view showing the light sources 10R, 10G, and 10B.

  Specifically, the light sources 10R, 10G, and 10B include a semiconductor layer (InGaAs layer) 14, a first mirror layer (first reflective portion, DBR layer) 15, an active layer 16, as shown in FIG. A second mirror layer (second reflecting portion, DBR layer) 17 is laminated in order. Then, the amplified laser light that resonates between the first mirror layer 15 and the second mirror layer 17 is emitted from the emission end face 10 a on which the semiconductor layer 14 is provided. The second mirror layer 17 reflects part of the laser light toward the first mirror layer 15 and transmits the remaining laser light in a direction different from that of the first mirror layer 15.

In the present embodiment, the wavelength changing means includes a second mirror layer 17, a reflecting portion (reflecting member) 18, and a glass plate (optical member) 19.
The reflection unit 18 is disposed on the optical path of the laser light that has passed through the second mirror layer 17 and reflects the incident laser light toward the emission end face 10a.
The glass plate 19 has optical transparency and is disposed on the optical path between the second mirror layer 17 and the reflecting portion 18. Further, the glass plate 19 is swingable about the axis P, and the laser light of the glass plate 19 (solid line shown in FIG. 5) in a state of being arranged perpendicular to the central axis O of the light. When the distance in the direction along the central axis O is S1, the optical path length is the refractive index of the glass plate 19 × the distance S1. Further, when the distance in the direction along the central axis O of the laser beam of the glass plate 19 (broken line shown in FIG. 5) at a certain time in the oscillated state is S2, the optical path length is the refractive index of the glass plate 19 × distance. S2. At this time, the distance S2 is longer than the distance S1. That is, the refractive index × distance S2 of the glass plate 19 is longer than the refractive index × distance S1 of the glass plate 19. Therefore, the optical distance between the first mirror layer 15 and the reflecting portion 18 changes.
Further, the output wavelength of the laser light emitted from each of the light sources 10R, 10G, and 10B is determined by the angle θ formed between the incident end face 19a of the glass plate 19 and the incident laser light, so that the glass plate 19 can be swung. Accordingly, the changing speed of the output wavelength of the emitted laser light is determined.

  In the image display device according to the present embodiment, the light transmitted through the second mirror layer 17 is used, and the first mirror layer 15 and the reflection unit 18 inside the light sources 10R, 10G, and 10B are reflected by the reflection unit 18 and the glass plate 19. Since the resonator length during the period changes, the output wavelength of the laser light emitted from the light sources 10R, 10G, and 10B changes with time. Therefore, since the speckle pattern projected on the screen 50 changes with time, the speckle pattern is integrated and averaged within the afterimage time of the human eye, and speckle noise can be suppressed.

It is possible to change the resonator length by changing the thickness of the glass plate 19 in the direction in which the laser light is incident and the refractive index of the constituent material.
Further, the optical distances S1 and S2 are changed by swinging the glass plate 19. However, the present invention is not limited to this. For example, by applying pressure to the glass plate 19, the optical distances S1 and S2 are changed. It may be changed.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

1 is a perspective view showing an image display device according to a first embodiment of the present invention. It is sectional drawing which shows the scanning means of FIG. It is a top view which shows the temperature adjustment part of FIG. It is a top view which shows the light source of the image display apparatus which concerns on 2nd Embodiment of this invention. It is a top view which shows the light source of the image display apparatus which concerns on 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image display apparatus, 10R ... Red light source (light source), 10G ... Green light source (light source), 10B ... Blue light source (light source), 15 ... 1st mirror layer (1st reflection part, DBR layer), 17 ... 2nd Mirror layer (second reflecting portion, DBR layer), 18 ... reflecting portion (wavelength changing means, reflecting member), 19 ... glass plate (wavelength changing means, optical member), 30 ... MEMS mirror (scanning means), 40 ... temperature Adjustment unit (wavelength changing means, temperature changing means), 50 ... screen (projected surface), 60 ... pressure changing part (wavelength changing means, pressure changing means)

Claims (10)

A light source that emits laser light;
Scanning means for scanning the laser light emitted from the light source toward the projection surface;
An image display device comprising: a wavelength changing unit that temporally changes an output wavelength of laser light emitted from the light source.   The image display apparatus according to claim 1, wherein the wavelength changing unit is a refractive index changing unit that temporally changes a refractive index of the light source.   The image display apparatus according to claim 1, wherein the wavelength changing unit is a temperature changing unit that temporally changes the temperature of the light source.   The image display apparatus according to claim 1, wherein the wavelength changing unit is a pressure changing unit that temporally changes a pressure applied to the light source. The light source transmits a part of the incident light in a direction different from that of the first reflection part, the first reflection part provided on the emission end surface side from which the laser light is emitted, and transmits the remaining light to the first reflection part A second reflecting portion that reflects toward the first reflecting portion;
The wavelength changing means has a reflecting member that reflects the light transmitted through the second reflecting portion toward the exit end surface, and has a light transmission property, and is on an optical path between the second reflecting portion and the reflecting member. 2. The image display device according to claim 1, further comprising: an optical member that is disposed on the second surface and changes an optical distance between the first reflecting portion and the reflecting member, and the second reflecting portion.   6. The image display device according to claim 1, wherein the change amount of the output wavelength of the laser light emitted from the light source has a color difference in a range of 5/1000 or less.   The wavelength changing unit periodically changes the output wavelength of the laser beam so that the frequency at which the output wavelength of the laser beam emitted from the light source changes does not synchronize with the frequency at which the scanning unit scans the laser beam. The image display device according to any one of claims 1 to 6, wherein the image display device is configured as described above.   The image display apparatus according to claim 1, wherein the wavelength changing unit changes the output wavelength of the laser light emitted from the light source aperiodically. The light source includes a red light source that emits red laser light, a green light source that emits green laser light, and a blue light source that emits blue laser light,
9. The system according to claim 1, wherein the wavelength changing unit is provided at least in the green light source and temporally changes an output wavelength of the green laser light emitted from the green light source. The image display device described in 1.   The wavelength changing means is provided in each of the red light source, the green light source, and the blue light source, and the red light source, the green light source, the red laser light emitted from the blue light source, the green laser light, and the blue laser light. The image display apparatus according to claim 9, wherein the output wavelength is changed with time.

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