JP2016114768A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device that can suppress a high-speed of a drive of a diffusion unit and the like, and can reduce speckle noise by reducing restrictions of a diffusion angle as curbing a luminance falling of an imaging image.SOLUTION: A light emitting device comprises: a light source that emits laser light; an image light creation unit that creates image light on the basis of the laser light emitted from the light source; a first diffusion unit that causes the image light to be diffused, and emits the diffused image light as first diffusion light; a second diffusion unit that is arranged opposing the first diffusion unit, causes the first diffusion light to be diffused, and emits the diffused first diffusion light as second diffusion light; and a drive unit that causes at least one of the first diffusion unit and the second diffusion unit to be relatively driven with respect to other thereof. The first diffusion unit has a first focus, and the second diffusion unit has a second focus, in which the second focus is orthogonal to an optical axis of the first diffusion unit, is positioned on a focal plane passing the first focus, and the first diffusion unit and the second diffusion unit are arranged with first diffusion unit and the second diffusion unit mutually opposite via the focal plane.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device that diffuses and emits image light.

  Patent Document 1 discloses a diffusing optical element that diffuses a light beam from a laser light source in order to suppress speckle noise generated in a projected image due to the coherency of the laser light in an illumination device using a laser light source, A configuration including a vibration unit that reciprocally vibrates the diffusion optical element is disclosed.

Japanese Patent No. 5168936 JP 2012-159823 A

  However, in the illumination device of Patent Document 1, the irradiation position of the laser beam is shifted by vibrating the diffusing optical element, but in order to shift the irradiation position with certainty, complicated control such as increasing the speed of vibration is performed. At the same time, the mechanical load on the drive system increases. Further, if the diffusion optical element is vibrated at high speed, there are many problems such as generation of noise due to vibration, reduction in the life of the motor as the excitation unit, and generation of vibration of the entire apparatus due to vibration of the diffusion optical element. It was.

  Patent Document 2 arranges a first diffusing portion and a second diffusing portion facing each other on an optical path of light emitted from a laser light source, and vibrates the first diffusing portion located on the upstream side of the optical path. A projector is disclosed in which a second diffusion unit is fixed on the downstream side. By adopting such a configuration, in an apparatus having only one diffusing optical element such as the illumination apparatus of Patent Document 1, it is not necessary to increase the speed of vibration necessary for suppressing speckle noise. Generation of noise, reduction in motor life due to high speed driving, generation of vibration of the entire apparatus, and the like can be improved.

However, the projector of Patent Document 2 has the following problems.
(1) The brightness of the projected image decreases due to light scattering and absorption in the first and second diffusing sections.
(2) The projection light diffusion angle can only be a circular with a Gaussian distribution.
(3) It is difficult to keep the diffusion angle within the intended value.

  Therefore, the present invention can suppress the speed of the diffusion unit drive, the control complexity and noise accompanying the increase in speed, the life reduction of the drive system of the diffusion unit, and the occurrence of vibration of the entire apparatus. It is another object of the present invention to provide a light emitting device capable of reducing speckle noise by reducing the restriction on the diffusion angle while suppressing the decrease in luminance of the projected image.

  In order to solve the above-described problems, a light emitting device of the present invention includes a light source that emits laser light, an image light generation unit that generates image light based on the laser light emitted from the light source, and diffuses the image light. A first diffuser that emits as the first diffused light, a second diffuser that is disposed opposite to the first diffuser, diffuses the first diffused light, and emits the second diffused light, and the first diffuser And a driving unit that drives at least one of the second diffusing units relative to the other, the first diffusing unit has a first focal point, the second diffusing unit has a second focal point, The two focal points are orthogonal to the optical axis of the first diffusing unit and are located on a focal plane passing through the first focal point, and the first diffusing unit and the second diffusing unit are arranged to face each other through the focal plane. It is characterized by being.

  With such a configuration, since the light diffused by the first diffusion unit can be further diffused by the second diffusion unit, the effect of randomizing the dispersion of the diffusion conditions can be shared between the two diffusion units, The driving speed of the diffusing unit can be suppressed. Therefore, complicated control, generation of noise, reduction in the life of the drive system of the diffusion unit, generation of vibration of the entire apparatus, and the like can be suppressed. In addition, since the first diffusing unit and the second diffusing unit are arranged to face each other via the focal plane, the degree of freedom in the diffusion angle of the projection light can be increased.

  In the light emitting device of the present invention, each of the first diffusing unit and the second diffusing unit partially includes a microlens array, a transparent member having a surface shape of a concavo-convex pattern having a random pitch, and a material having a different refractive index. It is preferable to consist of any of transparent members.

  Thereby, the freedom degree of the diffusion angle of projection light can be raised, suppressing the brightness fall of a projection image.

  In the light emitting device of the present invention, each of the first diffusing unit and the second diffusing unit includes a microlens array in which a plurality of microlenses are arranged in a row, and the first focal point is a plurality of microlenses that the first diffusing unit has. It is preferable that the second focal point is the focal point of any one of the plurality of micro lenses included in the second diffusing unit.

  Thereby, the freedom degree of the diffusion angle of projection light can be raised, suppressing the brightness fall of a projection image.

  In the light emitting device of the present invention, it is preferable that the first diffusing portion and the second diffusing portion are formed so that the pitches or arrangements of the microlenses of the microlens array do not coincide with each other.

  As a result, the effect of increasing the number of different speckle patterns generated within a unit time can be expected, the effect of randomizing the speckle pattern can be enhanced, and speckle noise can be reduced.

  In the light emitting device of the present invention, each of the first diffusing unit and the second diffusing unit includes a first pattern that deflects the traveling directions of a plurality of lights that pass through spatially different regions, and spatially. It is preferable to form any one of a second pattern that gives a phase difference so that phases of a plurality of lights passing through different regions are different from each other.

  Thereby, the effect of randomizing the dispersion of the diffusion conditions can be further enhanced.

  In the light emitting device of the present invention, it is preferable that one of the first diffusion portion and the second diffusion portion forms a first pattern and the other forms a second pattern.

  In the light emitting device of the present invention, it is preferable that the first diffusing unit and the second diffusing unit form the same pattern of either the first pattern or the second pattern.

  In the light emitting device of the present invention, it is preferable that the first diffusing unit and the second diffusing unit are driven so as to move in a plane orthogonal to the respective optical axes.

  In the light emitting device of the present invention, each of the first diffusing unit and the second diffusing unit is a microlens array having a plurality of microlenses arranged in a row, and the first diffusing unit is fixed and the second diffusing unit is fixed. The diffusion unit is driven to move in a plane orthogonal to the optical axis, and the second diffusion unit is driven relative to the first diffusion unit, so that the plurality of microlenses of the second diffusion unit are It is preferable that the number of patterns to be expressed is the total sum of each matrix component expressed by the following formula (1).

here,
The surfaces orthogonal to the optical axis of the first diffusion part and the second diffusion part are defined by the X axis and the Y axis orthogonal to each other,
Δt is the elapsed time,
tq is one frame time,
tp is the time required for the micro lens of the second diffusion unit to move until it overlaps the position of the micro lens next to it,
Vx is the moving speed of the second diffusion part in the X-axis direction,
Px is the aperture of the micro lens in the X-axis direction,
Vy is the moving speed of the second diffusion part in the Y-axis direction,
Py is the aperture of the micro lens in the Y-axis direction.

  According to the present invention, it is possible to provide a light emitting device capable of reducing speckle noise by reducing the restriction on the diffusion angle while suppressing the decrease in luminance of the projected image.

It is a top view which shows the structure of the light-emitting device concerning embodiment of this invention. It is a block diagram which shows the structure of the light-emitting device concerning embodiment of this invention. It is a perspective view which shows the structural example of a micro lens array. (A) and (B) are planes showing the arrangement of the microlenses of the first microlens array and the microlenses of the second microlens array when two microlens arrays facing each other in the Z1-Z2 direction are used. FIG. (A), (B) is a top view which shows arrangement | positioning of the microlens of a microlens array, when there is one microlens array. It is a top view which shows the structure of the 1st spreading | diffusion part concerning a modification, and a 2nd spreading | diffusion part. It is a top view which shows the structure of the 1st spreading | diffusion part concerning another modification, and a 2nd spreading | diffusion part.

Hereinafter, a light emitting device according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view showing the configuration of the light emitting device 10 according to the present embodiment, FIG. 2 is a block diagram showing the configuration of the light emitting device 10, and FIG. 3 is a perspective view showing a configuration example of a microlens array. . In each figure, XYZ coordinates are shown as reference coordinates. As shown in FIG. 1, the Z1-Z2 direction is along the direction of the optical axis 40c of the first diffusion unit 40 and the optical axis 50c of the second diffusion unit 50, and the XY plane is a plane orthogonal to the Z direction. It is.

  As shown in FIG. 1, the light emitting device 10 includes a laser light source 20, a phase modulation unit 30, a condenser lens 31, a first diffusion unit 40, and a second diffusion unit 50. The phase modulation unit 30, the condensing lens 31, the first diffusion unit 40, and the second diffusion unit 50 are sequentially arranged from the laser light source 20 side. As shown in FIG. 2, the light emitting device 10 further includes a control unit 70, a memory 71, a motor driver 72, a laser driver 74, and an LCOS driver 75.

  The laser light source 20 is a light source that emits laser light in the visible region, and emits light having an intensity corresponding to the amount of current supplied from the laser driver 74. The amount of current supplied from the laser driver 74 is controlled by the control unit 70.

  The phase modulation unit 30 is a reflective LCOS in the example shown in FIG. LCOS (Liquid Crystal On Silicon) is a panel having a liquid crystal layer and an electrode layer such as aluminum. In LCOS, electrodes that apply an electric field to a liquid crystal layer are regularly arranged to form a plurality of pixels. The tilt angle in the thickness direction of the crystal layer in the liquid crystal layer changes due to the change in the electric field strength applied to each electrode, and the phase of the transmitted laser beam is changed for each pixel. Such a phase change for each pixel is controlled by the LCOS driver 75. An instruction signal corresponding to the image data is sent to the LCOS driver 75 from the control unit 70 that has read the image data stored in the memory 71 in advance, and according to this instruction signal, the LCOS driver 75 performs the LCOS driver 75 for each pixel of the LCOS. By controlling the phase change, predetermined phase-modulated light is generated.

  This phase-modulated light is incident on a condenser lens 31 as a Fourier transform lens (FT lens). In the condensing lens 31, the phase-modulated light is condensed and Fourier-transformed to generate image light. This image light forms an image on the first diffusion unit 40.

  Here, the phase modulation unit 30 and the condensing lens 31 constitute an image light generation unit that generates image light based on the laser light emitted from the laser light source 20. Note that the phase modulation unit 30 may use a transmission LCOS or other phase modulation elements in addition to the reflection LCOS. Further, it is also possible to generate image light by using a galvano mirror or a polygon mirror as the image light generation unit and scanning the emitted light from the laser light source 20 line by line with the galvano mirror or the polygon mirror.

  Each of the first diffusing unit 40 and the second diffusing unit 50 is a translucent microlens array, and like the microlens array 60 illustrated in FIG. 3, a plurality of microlenses 61 having the same shape are X1-X2. And the Y1-Y2 direction are arranged in rows at regular intervals. The microlens array 60 includes a flat surface portion 60a in which the planar first surfaces of the microlenses 61 are connected, and a curved surface portion 60b in which the curved second surfaces of the microlenses 61 are arranged. The plurality of microlenses 61 have an optical axis 61c and a focal point 61f, respectively, and a surface connecting the focal points 61f forms a focal plane 62. The focal plane 62 is orthogonal to the optical axis 60 c of the microlens array 60. Here, the optical axis 60c is a straight line connecting the centers of the entire microlens array 60, and the optical axis 40c of the first diffusion unit 40 and the optical axis 50c of the second diffusion unit 50 are the same.

  As shown in FIG. 1, the first diffusing unit 40 and the second diffusing unit 50 are arranged so that the respective optical axes 40 c and 50 c are placed on the optical axis 20 c of the laser light source 20, and the curved surface parts 40 b and 50 b. Are facing each other. As shown in FIG. 1, the microlens 41 of the first diffusing unit 40 and the microlens 51 of the second diffusing unit 50 have different curvature radii on the curved second surface. In the first diffusion unit 40, the emitted light from the phase modulation unit 30 is incident on the flat surface part 40a, and the diffused light is emitted from each microlens 41 of the curved surface part 40b. These diffused lights are incident on each microlens 51 of the curved surface part 50b of the second diffusing part 50 and are emitted as diffused light from the flat part 50a. As shown in FIG. 1, the diffusion angle θ2 of the diffused light emitted from the second diffuser 50 is larger than the diffusion angle θ1 of the diffused light emitted from the first diffuser 40.

  The minute lenses 41 of the first diffusing unit 40 and the minute lenses 51 of the second diffusing unit 50 are formed to have different pitches and arrangements on the XY plane orthogonal to the optical axis 20c of the laser light source 20. Here, the pitch is the distance between the optical axes of the microlenses, and the array is the direction in which the microlenses are arranged on the XY plane.

  The first diffusing unit 40 has a focal plane 42 that connects the focal point 41 f (first focal point) on the rear side (image side) of each microlens 41, and the second diffusing unit 50 is the front side of each microlens 51. The focal point (second focal point) of the (laser light source 20 side) is disposed on the focal plane 42. Therefore, the first diffusing unit 40 and the second diffusing unit 50 are arranged to face each other with the focal plane 42 interposed therebetween.

  The first diffusing unit 40 is connected to a rotating shaft of a motor 73 driven by a motor driver 72, and rotates in a constant direction at a predetermined speed around the optical axis 40c. The motor driver 72 supplies a current corresponding to the rotation speed of the first diffusion unit 40 to the motor 73 in accordance with an instruction signal from the control unit 70. On the other hand, since the second diffusion unit 50 is fixed, the first diffusion unit 40 is driven relative to the second diffusion unit 50.

  Here, the first diffusing unit 40 may be rotated around the optical axis 40c within a certain angle range with respect to the optical axis 40c, instead of rotating. Alternatively, the first diffusion unit 40 may be fixed and the second diffusion unit 50 may be rotated or rotated about the optical axis 50c.

  Next, referring to FIG. 4 and FIG. 5, the speckle in the case where two microlens arrays are used as the two opposing diffusion parts and the case where there is one microlens array as the diffusion part. The difference in the number of diffusion patterns (speckle patterns) that contribute to noise reduction will be described. FIGS. 4A and 4B show microlenses L11 of the first microlens array D1, when two microlens arrays D1 and D2 facing each other in the Z1-Z2 direction along the optical axis direction are used. FIGS. 5A and 5B are plan views showing the arrangement of the microlenses L21 and L22 of L12 and the second microlens array D2, and FIGS. 5A and 5B are microlenses of the microlens array D10 when there is one microlens array. It is a top view which shows arrangement | positioning of L110 and L120. 4A and 5A show the arrangement of the microlenses in the initial state at time t = 0, and FIGS. 4B and 5B show the microlenses after the time Δt has elapsed. It is a figure which shows arrangement | positioning. In the following description, “*” is a multiplication symbol.

  4A and 4B, the first microlens array D1 is fixed, and the second microlens array D2 is displaced in the XY plane. Therefore, the second microlens array D2 is driven relative to the first microlens array D1. The following description holds true similarly when the first diffusion unit 40 is driven and the second diffusion unit 50 is fixed as shown in FIG.

  FIG. 4B shows the movement speed (displacement speed) of the second microlens array D2 in the X1-X2 direction as Vx in the lapse of time Δt from FIG. 4A to FIG. 4B. As described above, the movement amount of the second microlens array D2 is Vx * Δt. Therefore, two patterns corresponding to the microlenses L21 and L22 are formed in the area A11 corresponding to one lens L11 of the first microlens array D1. The same applies to the area A12 corresponding to the lens L12. The lengths of these two patterns in the X1-X2 direction are (Px−Vx * Δt) and (Vx * Δt) as shown in FIG. When these lengths are expressed as a ratio, they are (1− (Vx * Δt) / Px) and ((Vx * Δt) / Px).

  The pattern corresponding to the two microlenses of the second microlens array D2 is formed in the area corresponding to one lens of the first microlens array D1 as well in the Y1-Y2 direction. The ratio of the lengths of the two patterns formed in the lens area is (1- (Vy * Δt) / Py) and ((Vy * Δt) / Py).

  From the above, the number of patterns contributing to speckle noise removal can be expressed by the following equation.

here,
A plane orthogonal to the optical axis of the light source is defined by an X axis and a Y axis orthogonal to each other,
Δt is the elapsed time,
tq is one frame time,
tp is the time required for the micro lens of the second micro lens array D2 to move until it overlaps the position of the adjacent micro lens,
Vx is the moving speed of the second microlens array D2 in the X-axis direction,
Px is the aperture of the micro lens of the second micro lens array D2 in the X-axis direction,
Vy is the moving speed of the second microlens array D2 in the Y-axis direction,
Py is the aperture of the micro lens of the second micro lens array D2 in the Y-axis direction.

  Note that the observer is an observer of the hologram image emitted from the light emitting device 10, and one frame time is the time required for displaying an image for one frame by the image light.

  On the other hand, in FIGS. 5A and 5B, the microlens array D10 is displaced in the XY plane, but the second microlens array is not provided. In the passage of time Δt from FIG. 5A to FIG. 5B, when the moving speed (displacement speed) in the X1-X2 direction of the microlens array D10 is Vx, as shown in FIG. 5B. Furthermore, the movement amount of the microlens array D10 is Vx * Δt. However, in the case shown in FIGS. 5A and 5B, since there is one microlens array as the diffusing unit, the area of one lens as in the case shown in FIGS. 4A and 4B. Two patterns are not formed, but the same pattern is considered to have moved. The same applies to the Y1-Y2 direction.

  From the above, in the case shown in FIGS. 5A and 5B, the number of patterns contributing to speckle noise removal can be expressed by the following equation.

here,
tp is the time required for the micro lens of the micro lens array D10 to move until it overlaps the position of the adjacent micro lens,
Vx is the moving speed of the microlens array D10 in the X-axis direction,
Px is the aperture of the micro lens of the micro lens array D10 in the X-axis direction,
Vy is the moving speed of the microlens array D10 in the Y-axis direction,
Py is the aperture of the micro lens of the micro lens array D10 in the Y-axis direction.

  When the number of patterns shown in FIGS. 4A and 4B is compared with the number of patterns shown in FIGS. 5A and 5B, two microlens arrays are arranged. It can be seen that the examples shown in (A) and (B) have an overwhelmingly large number of patterns.

  Therefore, in the configuration in which two microlens arrays are arranged and one is relatively driven with respect to the other, variation in diffusion conditions is randomized as compared to the case where only one microlens array is provided. It is preferable for removing speckle noise. In addition, compared to the case where only one microlens array is used, the use of two microlens arrays can obtain the same number of patterns at a low rotational speed, so that vibration of the microlens array can be suppressed. It is possible to suppress noise caused by high-speed rotation, a reduction in the life of the drive system, and the occurrence of vibrations in the entire apparatus.

A modification will be described below.
In the above-described embodiment, the microlens array is used as the first diffusing unit and the second diffusing unit. However, as an optical member that can diffuse and emit incident light, for example, the surface shape of a concavo-convex pattern with random pitch The transparent member which has and the transparent member which partially has the material from which refractive index differs can be used. Here, both the first diffusing portion and the second diffusing portion are made of the above-described microlens array, the transparent member having the surface shape of the concavo-convex pattern of the random pitch, and the transparent member partially having the material having different refractive index You may comprise only in any 1 type of these, and may combine.

  Moreover, it is preferable that a 1st spreading | diffusion part and a 2nd spreading | diffusion part are used as the member which produces | generates the pattern (1st pattern) from which light intensity differs, or the member which produces | generates a pattern (2nd pattern) with a phase difference. Patterns with different light intensities are generated by deflecting a plurality of light passing through spatially different regions so that the traveling directions thereof are different from each other. For example, in a microlens array, for each crystal layer in a liquid crystal layer The light intensity distribution of the diffused light can be changed by changing the tilt angle. A pattern having a phase difference is generated by giving a phase difference so that phases of a plurality of lights passing through spatially different regions are different from each other, and has a surface shape of an uneven pattern with a random pitch. By using a transparent member or a transparent member that partially includes a material having a different refractive index, it becomes possible to emit diffused light having a different phase difference for each region in accordance with the uneven pattern and the refractive index distribution.

  Here, one of the first diffusion unit and the second diffusion unit may form a pattern having different light intensity, and the other may form a pattern having a phase difference, or the first diffusion unit and the second diffusion unit. Both parts may form any one of the same patterns. As an example of the former, as shown in FIG. 6, on the optical axis 20c of the laser light source 20, in order from the laser light source 20 side, a transparent screen 140 capable of generating a pattern having an optical phase difference as a first diffusion unit; There is a configuration in which a microlens array 150 capable of generating patterns with different light intensities is disposed as the second diffusion unit. According to this configuration, the image light emitted from the laser light source 20 and generated by being phase-modulated by the phase modulation unit 30 is emitted light having a phase difference for each region by the transparent screen 140. The lens array 150 emits diffused light having different light intensity for each region to the outside. Thereby, since the dispersion | variation in a spreading | diffusion condition is further randomized, a speckle noise can be reduced effectively.

  Further, as shown in FIG. 7, the first screen 260 and the first microlens array 240 are combined as the first diffusion unit 280, and the second microlens array 250 and the second screen 270 are combined as the second diffusion unit 290. Other configurations are possible. The first screen 260 is a transparent screen capable of generating a pattern having a phase difference, and the second screen 270 is a transparent screen capable of generating a pattern having different light intensity. The first microlens array 240 and the second microlens array 250 diffuse and emit incident light. According to this configuration, the image light emitted from the laser light source 20 and generated by being phase-modulated by the phase modulation unit 30 becomes light having a phase difference for each region by the first screen 260, and the first microlens array. 240 is emitted as diffused light. The diffused light is further diffused by the second microlens array 250 and is emitted to the outside as diffused light having different light intensities on the second screen 270. Thereby, since the dispersion | variation in a spreading | diffusion condition is further randomized, a speckle noise can be reduced effectively.

  In addition, the relative driving of the first diffusing unit and the second diffusing unit is not limited to rotation or rotation in the XY plane as in the above-described embodiment. It is preferable because the variation can be randomized, and the effect of reducing speckle noise can be enhanced by making the curved surface shape more complex.

  With the configuration as described above, the following effects can be obtained according to the embodiment and the modification.

(1) As described above, the first diffusion unit 40 and the second diffusion unit 50, which are driven relatively to each other, are arranged, so that the light diffused by the first diffusion unit 40 is further added to the second diffusion unit 50. Therefore, the effect of randomizing the dispersion of the diffusion conditions can be shared by the two diffusion units, and thereby the driving speed of each diffusion unit can be kept low. Therefore, complicated control, generation of noise, reduction in the life of the drive system of the diffusion unit, generation of vibration of the entire apparatus, and the like can be suppressed.

(2) Since the first diffusing unit 40 and the second diffusing unit 50 are arranged to face each other via the focal plane 42, the degree of freedom of the projection light diffusion angle can be increased. This effect can be further enhanced by arranging the focal point of the microlens array of the second diffusion unit 50 on the focal plane 42.

(3) Since the first diffusing unit 40 and the second diffusing unit 50 are configured by a microlens array in which a plurality of microlenses are arranged in a row, the diffusion angle of the projection light is suppressed while suppressing a decrease in luminance of the projection image. Can increase the degree of freedom.

(4) The effect of randomizing variation in diffusion conditions is enhanced by forming the first diffusion unit 40 and the second diffusion unit 50 so that the pitches and arrangements of the microlenses of the microlens array do not coincide with each other. Can do.

(5) In the first diffusing unit and the second diffusing unit, the first pattern deflected so that the traveling directions of the plurality of lights passing through the spatially different regions are different from each other, and the spatially different regions. By forming any one of the second patterns that give the phase difference so that the phases of the plurality of lights are different from each other, it is possible to further enhance the effect of randomizing the dispersion of the diffusion conditions.

  Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment, and can be improved or changed within the scope of the purpose of the improvement or the idea of the present invention.

  As described above, the light emitting device according to the present invention is useful in that speckle noise can be reduced while suppressing the speeding up of the diffusion unit and the like.

DESCRIPTION OF SYMBOLS 10 Light emitting apparatus 20 Laser light source 20c Optical axis 30 Phase modulation part (LCOS)
31 Condensing Lens 40 First Diffusion Unit 40c Optical Axis 41 Micro Lens 42 Focal Surface 50 Second Diffuser 50c Optical Axis 51 Micro Lens 60 Micro Lens Array 61 Micro Lens 61f Focus 62 Focal Surface 70 Control Unit 140 Transparent Screen 150 Micro Lens Array 240 First microlens array 250 Second microlens array 260 First screen 270 Second screen 280 First diffuser 290 Second diffuser D1 First microlens array D2 Second microlens array L11, L12, L21, L22 Micro lens

Claims (9)

A light source that emits laser light;
An image light generation unit that generates image light based on the laser light emitted from the light source;
A first diffusion unit that diffuses the image light and emits the first diffused light;
A second diffusing section that is disposed opposite to the first diffusing section, diffuses the first diffusing light, and emits the second diffusing light;
A drive unit that drives at least one of the first diffusion unit and the second diffusion unit relative to the other, and
The first diffuser has a first focal point; the second diffuser has a second focal point;
The second focal point is located on a focal plane orthogonal to the optical axis of the first diffusing unit and passing through the first focal point,
The light emitting device, wherein the first diffusing portion and the second diffusing portion are arranged to face each other with the focal plane interposed therebetween.   Each of the first diffusion portion and the second diffusion portion is a microlens array, a transparent member having a surface shape of a concavo-convex pattern with a random pitch, or a transparent member partially having a material having a different refractive index. The light emitting device according to claim 1, wherein The first diffusing unit and the second diffusing unit include a microlens array in which a plurality of microlenses are arranged in a row,
The first focal point is a focal point of any one of the plurality of micro lenses included in the first diffusion unit,
3. The light emitting device according to claim 1, wherein the second focal point is a focal point of any one of the plurality of micro lenses included in the second diffusion unit.   4. The light emitting device according to claim 3, wherein the first diffusing unit and the second diffusing unit are formed so that pitches or arrangements of the microlenses of the microlens array do not coincide with each other.   The first diffusing unit and the second diffusing unit each include a first pattern that deflects the light traveling directions that pass through spatially different regions to be different from each other, and a plurality that passes through spatially different regions. 5. The light emitting device according to claim 1, wherein any one of the second pattern and the second pattern that gives a phase difference is formed so that the phases of the light beams are different from each other.   6. The light emitting device according to claim 5, wherein one of the first diffusion part and the second diffusion part forms the first pattern, and the other forms the second pattern.   The light emitting device according to claim 5, wherein the first diffusion unit and the second diffusion unit form the same pattern of either the first pattern or the second pattern.   The said 1st spreading | diffusion part and the said 2nd spreading | diffusion part are driven so that it may move in the surface orthogonal to each optical axis, The any one of Claims 1-7 characterized by the above-mentioned. Light emitting device. Each of the first diffusion unit and the second diffusion unit is a microlens array having a plurality of microlenses arranged in a row,
The first diffusion unit is fixed, and the second diffusion unit is driven to move in a plane perpendicular to the optical axis;
When the second diffusing unit is driven relative to the first diffusing unit, the number of patterns expressed by the plurality of microlenses of the second diffusing unit is represented by the following formula (1). The light emitting device according to claim 1, wherein the light emitting device is a total sum of matrix components.

here,
A plane orthogonal to the optical axis of the first diffusion part and the second diffusion part is defined by an X axis and a Y axis orthogonal to each other,
Δt is the elapsed time,
tq is one frame time,
tp is the time required for the micro lens included in the second diffusing section to move until it overlaps the position of the adjacent micro lens,
Vx is the moving speed of the second diffusion part in the X-axis direction,
Px is the aperture of the micro lens in the X-axis direction,
Vy is the moving speed of the second diffusion part in the Y-axis direction,
Py is the aperture of the micro lens in the Y-axis direction.

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