JP2016075859A - Optical scanner, optical module, illumination device, and projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner that is inexpensive and excellent in durability and reliability, and an illumination device and a projection device including the optical scanner.SOLUTION: The optical scanner includes a drive unit that drives to rotate a rotation shaft, a first member penetrating the rotation shaft and fixed to the rotation shaft, and a second member disposed on the first member and together with the first member, penetrating the rotation shaft and fixed to the rotation shaft. A surface of the second member on an opposite side to the first member side is a mirror surface to reflect incident light; and a normal direction of the mirror surface is inclined from an axial direction of the rotation shaft.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an optical scanning device that scans coherent light, an optical module, an illumination device, and a projection device.

  For example, as disclosed in Patent Document 1, an illumination device using an optical element including a lens array or a hologram is known. The illumination device disclosed in Patent Literature 1 includes an irradiation device that includes a light source that emits light and a scanning device that periodically changes the optical path of the light from the light source.

  As shown in FIG. 13, the scanning device 95 of Patent Document 1 includes a reflection device 96 that can rotate around one axis Rx, and a deflecting element 97 that collimates light from the reflection device 96 by a lens effect. Contains. The light from the irradiation device 90 follows the optical path of the parallel light flux and enters the optical element 99. When such an irradiation apparatus 90 is used, since the incident light to the optical element comes from one direction, the optical element can be easily designed and manufactured. In addition, unlike the divergent light beam, when the light travels along the optical path of the parallel light beam, the optical path width does not vary. Therefore, it becomes easy to handle light, and the apparatus can be miniaturized.

JP 2012-123381 A

  However, light from a light source, for example, laser light from a laser light source, usually has a certain spot diameter when incident on the deflection element 97. For this reason, as shown in FIG. 13, even if the optical axis Lax1 of incident light can be deflected in a predetermined direction at each moment, the traveling directions of all the light beams cannot be collimated. The traveling direction of the light that has not been collimated cannot be adjusted with high accuracy toward the illuminated area by the optical path adjustment function of the optical element. As a result, it becomes impossible to illuminate the illuminated area with high accuracy from a desired direction while using the light source light with high utilization efficiency.

  Further, in the irradiation device 90 of FIG. 13, in order to make the speckle due to the laser light inconspicuous, the reflection angle of the laser light is continuously switched by the reflection device 96, and the laser light at each point on the optical element 99 is changed. The incident direction is changed according to time.

  In order to make speckles inconspicuous, it is effective to change parameters such as polarization, phase, angle and time in a multiple manner. A commercially available product such as a MEMS scanner or a galvano scanner can be used as a mounting form of the reflection device 96, but the galvano scanner is suitable for scanning light in a large angle range, but is not suitable for scanning in a small angle range. Not suitable for scanning. Further, the galvano scanner has a problem that the product life is short because the load on the mechanism member is large. Conversely, since the MEMS scanner is small in size, it is difficult to scan with high-power laser light.

  In the reflection device 96 of FIG. 13, the laser beam may be scanned while changing the reflection direction with respect to the incident light, and a complicated scanning function and a speed and angle control function are not necessarily required. For this reason, there is a demand for a reflection device having a simple configuration at low cost and excellent in durability and reliability.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical scanning device that is low in cost and excellent in durability and reliability, and an illumination device including the optical scanning device, and Providing a projection device.

In order to solve the above-described problem, in one aspect of the present invention, a driving unit that rotationally drives the rotating shaft;
A first member that passes through the rotating shaft and is fixed to the rotating shaft;
A second member disposed on the first member and penetrating the rotating shaft together with the first member and fixed to the rotating shaft;
The surface of the second member opposite to the surface of the first member is a mirror surface that reflects incident light, and a normal direction of the mirror surface is inclined from the axial direction of the rotating shaft. Provided.

  You may provide the 1st support tool joined to a part of said mirror surface of the said 2nd member, and fixing the said 2nd member to the said rotating shaft.

The area of the upper surface of the first support is smaller than the area of the mirror surface,
The first support may be arranged at a rotation center position on the mirror surface.

  The first support may be joined on the mirror surface.

  The first support may be joined to an inner surface of a recess formed along the mirror surface of the second member.

  The upper surface of the first support may be a mirror surface.

  You may provide the 2nd support which fixes the said 1st member to the said rotating shaft on the opposite side to the said 2nd member of the said 1st member.

  The mirror surface of the second member and the surface on the opposite side may be non-parallel.

  The mirror surface may be a polished surface or a metal-deposited surface.

  You may provide the controller which controls the rotation speed or rotation frequency of the said rotating shaft with respect to the said drive part.

The optical scanning device described above;
There may be provided an optical module comprising: an optical element capable of diffusing the coherent light reflected by the optical scanning device with respect to the entire region within a predetermined region.

An optical element capable of diffusing the coherent light incident on each position to the entire area within a predetermined area;
An illumination device that irradiates the optical element with the coherent light so that coherent light scans the surface of the optical element,
The irradiation device includes:
A light source that emits coherent light;
An optical scanning device that changes a traveling direction of the coherent light emitted from the light source and scans the surface of the optical element with the coherent light.

A spatial light modulator that is disposed at a position overlapping the predetermined region and is illuminated by a lighting device to generate a light-modulated image;
A projection optical system that projects the light-modulated image onto a projection member.

  According to the present invention, it is possible to provide an optical scanning device that is low in cost and excellent in durability and reliability, and an illumination device and a projection device that include the optical scanning device.

The figure which shows schematic structure of the projection type video display apparatus by one Embodiment of this invention. The perspective view which shows the irradiation apparatus of the illuminating device contained in the projection apparatus of FIG. 1 is a diagram showing a schematic configuration of a projection display apparatus 10 in which a single reflection device 71 is provided in a scanning device 70. FIG. Sectional drawing which shows an example of the specific structure of a 1st reflective device and a 2nd reflective device. Sectional drawing which shows the 1st modification of a 1st reflective device and a 2nd reflective device. Sectional drawing which shows the 2nd modification of a 1st reflective device and a 2nd reflective device. Sectional drawing which shows the 3rd modification of a 1st reflective device and a 2nd reflective device. (A) And (b) is a figure which shows the motion of a 1st member and a 2nd member when rotating a shaft member. (A) And (b) is sectional drawing which shows the 4th modification of a 1st reflective device and a 2nd reflective device. The figure which shows an example of an optical element. The figure which shows the example in which a light source device contains a some light source. The figure which shows the example in which an optical element contains a hologram recording medium. The side view which shows the conventional scanning device.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

  In addition, as used in this specification, the shape and geometric conditions and the degree thereof are specified, for example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

  FIG. 1 is a diagram showing a schematic configuration of a projection display apparatus 10 according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an irradiation device of an illumination device included in the projection device of FIG.

  A projection video display device 10 shown in FIG. 1 includes a screen 15 and a projection device 20 that projects video light. The projection device 20 includes an illumination device 40 that illuminates an illuminated area LZ located on a virtual plane, a spatial light modulator 30 that is disposed at a position overlapping the illuminated area LZ, and is illuminated by the illumination device 40, and spatial light modulation. And a projection optical system 25 that projects the coherent light from the device 30 onto the screen 15. That is, the illumination device 40 according to the present embodiment is incorporated in the projection device 20 as an illumination device for illuminating the spatial light modulator 30. The illuminating device 40 illuminates the illuminated area LZ with coherent light, and the illuminating device 40 is devised to make speckles inconspicuous.

  First, the illumination device 40 will be described. As illustrated in FIG. 1, the illumination device 40 includes an optical element 50 that directs the traveling direction of light toward the illuminated region LZ, and an irradiation device 60 that irradiates the optical element 50 with coherent light. . The irradiation device 60 scans the optical element 50 with coherent light. Accordingly, at a certain moment, the region on the optical element 50 that is irradiated with the coherent light by the irradiation device 60 becomes a part of the surface of the optical element 50.

  The irradiation device 60 includes a light source device 61 that emits coherent light in a specific wavelength band, and a scanning device 70 that directs the traveling direction of light from the light source device 61 toward the optical element 50. The light source device 61 includes a light source 62 that generates coherent light, for example, a laser light source 62. The scanning device 70 causes the coherent light generated by the light source 62 of the light source device 61 to enter the optical element 50 so as to follow the optical path of the light beam that forms a parallel light beam.

  The scanning device 70 includes a first reflection device 71 having a first reflection surface 72 that reflects light from the light source 62 and a second reflection device 73 having a second reflection surface 74 that reflects light from the first reflection surface 72. And a controller 75 connected to the first reflection device 71 and the second reflection device 73. The direction of the first reflecting surface 72 of the first reflecting device 71 can be repeatedly varied within a predetermined movable range. Similarly, the direction of the second reflecting surface 74 of the second reflecting device 73 can be repeatedly varied within a predetermined movable range. The light emitted from the light source 62 scans the optical element 50 by repeatedly changing the direction of the first reflecting surface 72 and the direction of the second reflecting surface 74. The controller 75 controls the direction of the first reflecting surface 72 and the direction of the second reflecting surface 74.

  In the scanning device 70 described here, the change in the direction of the first reflection surface 72 of the first reflection device 71 and the change in the direction of the second reflection surface 74 of the second reflection device 73 are synchronized. Accordingly, one of the direction of the first reflecting surface 72 and the direction of the second reflecting surface 74 is directed in a predetermined direction according to the other direction. More specifically, the scanning device 70 operates the first reflecting surface 72 and the second reflecting surface 74 so that the direction of the first reflecting surface 72 and the direction of the second reflecting surface 74 are parallel to each other.

  In the illustrated example, the first reflecting device 71 includes a reflecting member 71a having a first reflecting surface 72, a shaft member 71b that supports the reflecting member 71a, and a drive device 71c connected to the shaft member 71b. Have. As shown in FIG. 2, the shaft member 71 b is driven by a driving device 71 c made of a motor, for example, so that the shaft member 71 b can rotate around the first rotation axis Ra <b> 1 that is the axial direction. As the shaft member 71b rotates, the reflecting member 71a supported by the shaft member 71b also rotates about the first rotation axis Ra1. However, the first reflecting surface 72 is not orthogonal to the first rotation axis Ra1. In other words, the normal direction of the first reflecting surface 72 is not parallel to the first rotation axis Ra1 and is inclined with respect to the first rotation axis Ra1. Therefore, when the reflecting member 71a rotates about the first rotation axis Ra1, the first reflecting surface 72 changes its direction. At this time, if the rotation of the reflecting member 71a is constant, the direction of the first reflecting surface 72 periodically varies around the first virtual surface Vp1 orthogonal to the first rotation axis Ra1.

  In the illustrated example, the second reflection device 73 is configured in the same manner as the first reflection device 71. That is, the second reflection device 73 includes a reflection member 73a having a second reflection surface 74, a shaft member 73b that supports the reflection member 73a, and a driving device 73c connected to the shaft member 73b. .

  As shown in FIG. 2, the shaft member 73b is driven by a drive device 73c made of a motor, for example, so that the shaft member 73b can rotate about the second rotation axis Ra2 that is the axial direction thereof. As the shaft member 73b rotates, the reflecting member 73a supported by the shaft member 73b also rotates about the second rotation axis Ra2. However, the second reflection surface 74 is not orthogonal to the second rotation axis Ra2. In other words, the normal direction of the second reflecting surface 74 is not parallel to the second rotation axis Ra2 and is inclined with respect to the second rotation axis Ra2. Therefore, when the reflecting member 73a rotates about the second rotation axis Ra2, the second reflecting surface 74 changes its direction. At this time, if the rotation of the reflecting member 73a is constant, the direction of the second reflecting surface 74 is periodically changed around the second virtual surface Vp2 orthogonal to the second rotation axis Ra2.

  In the illustrated example, the first rotation axis Ra1 of the first reflection surface 72 and the second rotation axis Ra2 of the second reflection surface 74 are parallel to each other. Further, the rotation direction of the first reflection surface 72 around the first rotation axis Ra1 and the rotation direction of the second reflection surface 74 around the second rotation axis Ra2 are the same. And the rotation period of the 1st reflective surface 72 and the rotation period of the 2nd reflective surface 74 are the same. As a result, the first reflecting surface 72 and the second reflecting surface 74 are maintained in a state parallel to each other.

  The direction of rotation of the first reflecting surface 72 around the first rotation axis Ra1 is the first when the first reflecting surface 72 is observed from one side to the other side along the first rotation axis Ra1. The direction of rotation of the reflecting surface 72 (arrow AR1 in FIG. 2), and the direction of rotation of the second reflecting surface 74 around the second rotation axis Ra2 is the second rotation axis Ra2 parallel to the first rotation axis Ra1. The direction of rotation of the second reflecting surface 74 when the second reflecting surface 74 is observed from the one side to the other side along the arrow (arrow AR2 in FIG. 2).

  The method for controlling the orientations of the first reflecting surface 72 and the second reflecting surface 74 described above is merely an example, and other control methods can be employed. For example, the directions of the first reflecting surface 72 and the second reflecting surface 74 may be controlled by directly detecting the directions of the first reflecting surface 72 and the second reflecting surface 74.

  When the scanning device 70 as described above is used, the first reflecting surface 72 and the second reflecting surface 74 are maintained in parallel, so that the traveling direction of the light traveling from the second reflecting surface 74 is the first reflecting surface 72. It becomes parallel to the traveling direction of the light incident on. On the other hand, the light source 62 of the light source device 61 is fixed, and the light emitted from the light source 62 always travels from a certain direction toward the first reflection device 71. That is, the traveling direction of light from the light source 62 incident on the first reflecting surface 72 is always constant. Therefore, the light reflected by the second reflecting surface 74 of the second reflecting device 73 always travels in a certain direction. In the illustrated example, light always enters from the irradiation device 60 toward the optical element 50 from a certain direction. That is, the light from the irradiation device 60 enters the optical element 50 so as to follow the optical path of the light beam forming the parallel light flux.

  In this way, by synchronizing the change in the direction of the first reflection surface 72 of the first reflection device 71 with the change in the direction of the second reflection surface 74 of the second reflection device 73, the light from the light source 62 can be synchronized. It becomes possible to collimate with high accuracy. However, depending on the application of the illumination device 40 and the projection display apparatus 10, there may be a case where high-precision collimation is unnecessary. Therefore, a single reflection device may be provided in the scanning device 70.

  FIG. 3 is a diagram showing a schematic configuration of the projection display apparatus 10 in which a single reflection device 71 is provided in the scanning device 70. In the example of FIG. 3, the laser light from the light source 62 is reflected by the reflecting surface 72 of the reflecting device 71 and directly enters the optical element 50. Since the reflection device 71 varies the angle of the reflection surface 72, the incident direction and the incident position on the optical element 50 change with time. In the case of FIG. 3, the light incident on the optical element 50 is not collimated light, but can be sufficiently applied to a general illumination device or projection device.

  FIG. 4 is a cross-sectional view showing an example of a specific structure of the first reflection device 71 and the second reflection device 72. Since the first reflection device 71 and the second reflection device 72 have the same structure, the structure of the first reflection device 71 will be described below.

  The first reflection device 71 shown in FIG. 4 includes a driving device (driving unit) 71c that rotationally drives a shaft member 71b that constitutes a rotating shaft, and a first member 76 that passes through the shaft member 71b and is fixed to the shaft member 71b. And a second member 77 that is disposed on the first member 76 and penetrates the shaft member 71b together with the first member 76 and is fixed to the shaft member 71b. The surface of the second member 77 opposite to the surface of the first member 76 is a mirror surface 77a that reflects incident light, and the normal direction of the mirror surface 77a is inclined with respect to the axial direction of the shaft member 71b. . The first member 76 and the second member 77 are joined by, for example, an adhesive.

  Since the first member 76 and the second member 77 rotate together with the shaft member 71b, the first member 76 and the second member 77 need to be firmly joined to the shaft member 71b. This is because if the bonding force is weak, the first member 76 and the second member 77 may be detached from the shaft member 71b due to centrifugal force.

  Since the shaft member 71b is disposed so as to penetrate the first member 76 and the second member 77, an adhesive is applied to the peripheral surfaces of the through holes of the first member 76 and the second member 77, and the shaft member 71b and It is desirable to bond the contact surfaces of the first member 76 and the second member 77 with an adhesive.

  In addition to this, as shown in the first modified example of FIG. 5, the first support 78 is arranged on a part of the mirror surface 77 a of the second member 77, and the back surface of the first support 78 is set to the second member. You may join to the mirror surface 77a of 77, and the mirror surface 77a of the shaft member 71b. Thereby, the shaft member 71b is joined to the circumferential surfaces of the through holes of the first member 76 and the second member 77 on the outer circumferential surface thereof, and is joined to the first support 78 on the end surface thereof. Can be firmly fixed to the first member 76 and the second member 77.

  The first support 78 is disposed at a substantially central portion of the mirror surface 77 a of the second member 77. More specifically, the first support 78 is disposed at the rotation center position of the second member 77. The area of the upper surface of the first support 78 is smaller than the area of the mirror surface 77 a of the second member 77. When the upper surface of the first support 78 is not the mirror surface 77a, the incident light is reflected by the mirror surface 77a portion of the second member 77 where the first support 78 is not disposed.

  FIG. 6 is a cross-sectional view showing a second modification in which a second support 79 is provided in addition to FIG. The second support 79 is joined to the back surface of the first member 76 and is fixed to the shaft member 71b. The second support member 79 has a through hole through which the shaft member 71b passes, and is joined to the shaft member 71b with an adhesive, for example, on the peripheral surface of the through hole.

  Alternatively, as shown in the third modification of FIG. 7, the upper surface of the second support member 79 is joined to the back surface of the first member 76 with an adhesive or the like, and the screw hole formed on the side surface of the second support member 79. The second support 79 may be fixed to the shaft member 71b with the screw 80.

  In FIG. 6, the first member 78 fixes the second member 77 and the shaft member 71 b from the upper surface side of the second member 77, and the second support member 79 from the back surface side of the first member 76. Since the first member 76 and the shaft member 71b are fixed, the shaft member 71b can be fixed to the first member 76 and the second member 77 more firmly than in FIG.

  The mirror surface 77a of the second member 77 and the contact surface between the first member 76 on the opposite side are not parallel to each other. More specifically, the mirror surface 77a that is the upper surface of the second member 77 is an inclined surface in which the normal direction of the surface is inclined from the axial direction of the shaft member 71b.

  The material of the first member 76 is not particularly limited. In FIG. 4, it is assumed that the first member 76 is a base material having a uniform thickness. The second member 77 only needs to have a mirror surface 77 a whose upper surface is inclined, and the material of the base material constituting the second member 77 is not particularly limited. In order to form the inclined mirror surface 77a, the surface of the base material having a uniform thickness is polished or formed, or the base surface having a uniform thickness is cut obliquely to form an inclined surface and then polished. And a method of joining a mirror having a uniform thickness on an inclined surface formed by polishing or cutting. Here, any method may be adopted.

  The outer shape of the mirror surface 77a on the upper surface side of the second member 77 may be a circle, a rectangle, or other shapes.

  FIG. 8 is a diagram illustrating the movement of the first member 76 and the second member 77 when the shaft member 71b is rotated. The incident light from the light source 62 is always incident with the same beam diameter from the same direction, but the inclination angle of the mirror surface 77a of the second member 77 changes according to the rotation of the shaft member 71b. ), The reflection angle of the incident light continuously changes. As a result, the locus of the incident light is circular as shown in FIG.

  As shown in FIG. 5, in the case where the first support 78 is joined to the central part of the inclined mirror surface 77a of the second member 77, if the upper surface of the first support 78 is not the mirror surface 77a, no light is applied to this region. Therefore, the area where the light from the light source 62 can be incident is limited.

  Therefore, the upper surface of the first support 78 may be a mirror surface. The method of making the upper surface of the first support 78 a mirror surface may be any one of polishing, metal vapor deposition, and joining of mirror bodies. By making the upper surface of the first support 78 a mirror surface, light from the light source 62 can be incident on the entire inclined mirror surface 77 a of the second member 77, and the positional relationship between the light source 62 and the first reflection device 71. Is reduced, and optical design is facilitated.

  Even if the upper surface of the first support 78 is a mirror surface, as shown in FIG. 5, when the first support 78 protrudes from the mirror surface 77a of the second member 77, the mirror surface 77a is uneven. Thus, the direction of the reflected light of the light incident on the edge portion of the first support 78 becomes a factor.

  Therefore, as shown in a fourth modification of FIG. 9, a recess 77b is formed on the upper surface of the second member 77 to match the outer shape of the first support 78, and the first support 78 is placed inside the recess 77b. The first support 78 may be joined on the surface inside the recess 77b. Thereby, the unevenness | corrugation of the mirror surface 77a of the upper surface side of the 1st support tool 78 becomes small, and a possibility that a reflection direction may be disturbed decreases. In addition, the upper surface of the 1st support tool 78 in the structure of FIG. 9 may be made into a mirror surface, and does not need to be made into a mirror surface. Further, the recess 77b may have an inclined shape that matches the mirror surface 77a as shown in FIG. 9A, or it matches the surface that is orthogonal to the axial direction of the shaft member 71b as shown in FIG. 9B. Shape may be sufficient. In the case of FIG. 9A, since the upper surface of the first support 78 can be flush with the mirror surface 77a, it is more desirable, but it may take time to form the recess 77b. On the other hand, in the case of FIG. 9B, the mirror surface 77a and the upper surface of the first support 78 are not flush with each other, but it takes less time to form the recess 77b and the workability is good. The depth of the recess 77b in FIG. 9B is set to a depth that matches the thickness of the first support 78, and when the first support 78 is housed in the recess 77b, the unevenness of the mirror surface 77a is as small as possible. It is desirable to do so.

  The drive device 71c rotates the shaft member 71b by a control signal from the controller 75 shown in FIG. The controller 75 may supply a control signal capable of switching the rotation frequency of the shaft member 71b in a plurality of ways to the drive device 71c. Thereby, the controller 75 can drive the 1st reflective device 71 and the 2nd reflective device 73 synchronizing, and rotates the 1st reflective surface 72 and the 2nd reflective surface 74, maintaining a mutually parallel state. Can do.

  Further, a sensor that directly detects the rotation speed and rotation frequency of the shaft member 71b may be provided, and the driving device 71c may control the rotation frequency of the shaft member 71b based on a detection signal from the sensor. Although the specific form of a sensor is not ask | required, For example, the optical sensor which detects a rotation speed etc. optically, the Hall sensor which detects magnetically, the encoder which detects mechanically, etc. are applicable.

  Thus, since the shaft member 71 b is disposed so as to penetrate the first member 76 and the second member 77, the shaft member 71 b can be fixed to the first member 76 and the second member 77 with a simple structure. In addition, by making the upper surface of the second member 77 an inclined mirror surface 77a, the reflection direction of light incident on the mirror surface 77a can be continuously switched in accordance with the rotation of the shaft member 71b.

  The second member 77 has a wedge shape in cross-sectional shape, and when the second member 77 is rotated according to the shaft member 71b, the second member 77 has an asymmetric shape with respect to the center of rotation. There is a possibility that 71b may be eccentric, or cause abnormal noise or failure. For this reason, it is possible to perform a blanking process or the like that cuts a part of the second member 77 so that the position of the center of gravity of the second member 77 is as close to the center of rotation as possible.

  Next, the optical element 50 will be described. The optical element 50 shown in FIG. 1 has an optical path control function that directs incident light to each region in a specific direction according to the position of the region. The optical element 50 described here corrects the traveling direction of the incident light to each region and directs it to a predetermined region LZ. This area is the illuminated area LZ. That is, the light from the irradiation device 60 irradiated to each region obtained by dividing the incident surface of the optical element 50 into a plane illuminates at least a part of the overlapping region after passing through the optical element 50.

  FIG. 10 is a diagram illustrating an example of the optical element 50. The optical element 50 of FIG. 10 has a lens array 51 formed corresponding to the incident direction of light from the irradiation device 60. Here, the “lens array” is a collection of small lenses, also called unit lenses, and functions as an element that deflects the traveling direction of light by refraction or reflection. In the illustrated example, the optical element 50 diffuses the light incident on each region corresponding to each unit lens 51a so as to be incident on at least the entire illuminated region LZ. In other words, the optical element 50 illuminates the same illuminated area LZ by diffusing light incident from the irradiation device 60 into each area.

In the illustrated example, the light incident on the optical element 50 is light traveling along a certain direction.
Therefore, the lens array 51 shown in FIG. 4 is configured as a fly-eye lens in which unit lenses 51a made of convex lenses are spread. Each unit lens 51a is formed identical to each other. The unit lenses 51a are spread so that their optical axes are parallel to each other.

  Further, the optical element 50 shown in FIG. 10 has such a lens array 51 and a condenser lens 52 or a field lens arranged to face the lens array 51. In the optical element 50 of FIG. 10, the lens array 51 is disposed on the most incident light side of the optical element 50 and receives light from the irradiation device 60. Each unit lens 51a forming the lens array 51 converges the incident light to the focal point so as to follow the optical path of the light beam forming the parallel light flux. The condenser lens 52 is disposed on the surface defined by the focal point of each unit lens 51a, and directs the light from each convex lens to the illuminated region LZ. According to the condenser lens 52 of FIG. 10, the light from each convex lens can be directed only to the same illuminated area LZ, and the illumination light from each direction is superimposed on the illuminated area LZ.

  Next, the spatial light modulator 30 will be described. As shown in FIG. 1, the spatial light modulator 30 is disposed so as to overlap the illuminated area LZ. The spatial light modulator 30 is illuminated by the illumination device 40 to form a modulated image. The light from the illumination device 40 illuminates only the entire illuminated area LZ as described above. Therefore, it is preferable that the incident surface of the spatial light modulator 30 has the same shape and size as the illuminated region LZ irradiated with light by the illumination device 40. In this case, it is because the light from the illuminating device 40 can be utilized with high utilization efficiency for the formation of a modulated image.

  The spatial light modulator 30 is not particularly limited, and various known spatial light modulators can be used. For example, a spatial light modulator that forms a modulated image without using polarized light, such as a digital mirror device (DMD), a transmissive liquid crystal microdisplay that forms a modulated image using polarized light, or a reflective LCoS (Liquid) Crystal On Silicon (registered trademark) can be used as the spatial light modulator 30.

  As in the example shown in FIG. 1, when the spatial light modulator 30 is a transmissive liquid crystal microdisplay, the spatial light modulator 30 illuminated in a planar shape by the illumination device 40 is coherent light for each pixel. By selecting and transmitting, a modulated image is formed on the screen of the display forming the spatial light modulator 30. The modulated image thus obtained is finally projected onto the screen 15 by the projection optical system 25 at the same magnification or scaled. Thereby, the observer can observe the image projected on the screen 15. The screen 15 may be configured as a transmissive screen or may be configured as a reflective screen.

  Next, the operation of the illumination device 40, the projection device 20, and the projection display device 10 having the above-described configuration will be described.

  First, the irradiation device 60 irradiates the optical element 50 with coherent light so as to scan the optical element 50. Specifically, coherent light of a specific wavelength band traveling along a certain direction is generated by the light source 62 of the light source device 61, and the traveling direction of the coherent light is changed by the scanning device 70. The scanning device 70 performs a periodic operation, and as a result, the incident position of the coherent light on the optical element 50 also changes periodically.

  The coherent light incident on each area of the optical element 50 is superimposed on the illuminated area LZ by the optical path adjustment function of the optical element 50. That is, the coherent light incident on each region of the optical element 50 from the irradiation device 60 is diffused or expanded by the optical element 50 and enters the entire illuminated region LZ. In this way, the irradiation device 60 can illuminate the illuminated region LZ with coherent light.

  As shown in FIG. 1, in the projection device 20, the spatial light modulator 30 is arranged at a position overlapping the illuminated area LZ of the illumination device 40. For this reason, the spatial light modulator 30 is illuminated in a planar shape by the illumination device 40, and forms an image by selecting and transmitting the coherent light for each pixel. This image is projected onto the screen 15 by the projection optical system 25. The coherent light projected on the screen 15 is diffused and recognized as an image by the observer.

  In the illuminating device 40 described above, coherent light is irradiated onto the optical element 50 so as to scan the optical element 50. Further, the coherent light incident on each region of the optical element 50 from the irradiation device 60 illuminates the entire illuminated area LZ with the coherent light, but the illumination direction of the coherent light that illuminates the illuminated area LZ Are different from each other. And since the area | region on the optical element 50 in which coherent light injects changes with time, the incident direction of the coherent light to the to-be-illuminated area | region LZ also changes with time.

  Considering the illuminated area LZ as a reference, coherent light constantly enters each area in the illuminated area LZ, but the direction of incidence always changes as shown by an arrow A1 in FIG. It will be. As a result, the light forming each pixel of the image formed by the light transmitted through the spatial light modulator 30 is projected to a specific position on the screen 15 while changing the optical path over time as indicated by an arrow A2 in FIG. Will come to be.

  From the above, according to the illumination device 40 described above, the incident direction of the coherent light changes temporally at each position on the screen 15 displaying the image, and this change is This is a speed that cannot be resolved by the human eye. As a result, a non-correlated coherent light scattering pattern is multiplexed and observed in the human eye. Therefore, speckles generated corresponding to each scattering pattern are overlapped and averaged and observed by an observer. Thereby, speckles can be made very inconspicuous for an observer who observes the image displayed on the screen 15.

  Note that conventional speckles observed by humans include not only speckles on the screen caused by scattering of coherent light on the screen 15, but also scattering of coherent light before being projected on the screen. Speckle on the projection device side can also occur. The speckle pattern generated on the projection device side is projected onto the screen 15 via the spatial light modulator 30 so that it can be recognized by the observer. However, according to the present embodiment, the coherent light continuously scans on the optical element 50, and the coherent light incident on each region of the optical element 50 is covered with the spatial light modulator 30. The entire illumination area LZ is illuminated. That is, the optical element 50 forms a new wavefront that is separate from the wavefront used to form the speckle pattern, and is complex and uniform through the illuminated region LZ and further through the spatial light modulator 30. The screen 15 is illuminated. By forming a new wavefront in such an optical element 50, the speckle pattern generated on the projection device side is invisible.

  By the way, as shown in FIGS. 1 and 2, the light emitted from the light source 62 has a certain spot diameter. Even if the light having such a spot diameter is to be collimated by using a deflecting element 97 having a lens effect as shown in FIG. 13, only the direction of the optical axis can be controlled. In the deflection element 97 shown in FIG. 13, it is impossible to direct the optical paths of all the light beams passing through the respective positions within the spot diameter in a desired direction. On the other hand, according to the scanning device 70 having the two reflecting surfaces 72 and 74 maintained in parallel, the optical path of the light incident on the first reflecting surface 72 and the second reflecting surface regardless of the spot diameter. The optical path of the light reflected by 74 can be made parallel. In other words, regardless of the spot diameter of the light emitted from the light source 62, the irradiation device 60 can irradiate the optical element 50 with light so as to follow the optical path of the light beam forming the parallel light flux. The optical path of the light incident on the optical element 50 is adjusted with high accuracy in a predetermined direction by the optical element 50. That is, according to the scanning device 70 and the illumination device 40 described here, the illuminated region LZ can be illuminated with extremely high accuracy from a desired direction.

  Various modifications can be made to the above-described embodiment. Hereinafter, an example of modification will be described with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as in the above embodiment. A duplicate description is omitted.

  In the embodiment described above, the light source device 61 has the single light source 62. However, the present invention is not limited to this example, and the light source device 61 may include a plurality of light sources as shown in FIG. As an example, the light source device 61 may be configured as a laser array including a plurality of laser light sources. The plurality of light sources 66, 67, and 68 included in the light source device 61 may generate light having different wavelength bands, or may generate light having the same wavelength band. When the light sources 66, 67, and 68 in different wavelength bands are used, the illuminated region LZ can be illuminated with light of a color that cannot be generated by a single light source due to additive color mixing. When the light sources 66, 67, and 68 generate light in the red wavelength band, light in the green wavelength band, and light in the blue wavelength band, respectively, the illuminated region LZ can be illuminated with white light. On the other hand, when the light sources 66, 67, and 68 in the same wavelength band are used, the illuminated region LZ can be illuminated with high output.

  In the above-described embodiment, the example in which the optical element 50 includes the lens array 51 has been described. However, the present invention is not limited to this. As shown in FIG. 12, the optical element 50 may include a hologram recording medium 57. In the example shown in FIG. 12, the light irradiated from the irradiation device 60 and scanned on the hologram recording medium 57 is incident on each region on the hologram recording medium 57 so as to satisfy the diffraction condition of the hologram recording medium 57. It is incident at an angle. The light incident on each area of the hologram recording medium 57 from the irradiation device 60 is diffracted by the hologram recording medium 57 and illuminates areas overlapping each other at least partially. In the example shown in FIG. 7, light incident on each area of the hologram recording medium 57 from the irradiation device 60 is diffracted by the hologram recording medium 57 to illuminate the same illuminated area LZ. . For example, the light incident on each region of the hologram recording medium 57 from the irradiation device 60 may be superimposed on the illuminated region LZ to reproduce the image of the scattering plate.

  Furthermore, in the embodiment described above, the spatial light modulator 30 is arranged in the illuminated area LZ illuminated by the illumination device 40, but the present invention is not limited to this example. For example, the incident surface of the uniformizing optical system may be disposed in the illuminated area LZ. In this case, the light incident on the homogenizing optical system propagates through the homogenizing optical system while repeating total reflection, and is emitted from the homogenizing optical system. The illuminance at each position on the exit surface of such a homogenizing optical system is made uniform. For example, an integrator rod can be used as the homogenizing optical system. The spatial light modulator 30 can be disposed, for example, facing the exit surface of the homogenizing optical system.

  Further, in the above-described embodiment, the example in which the illumination device 40 is incorporated in the projection device 20 and the projection type image display device 10 is shown. However, the present invention is not limited to this, and the illumination device 40 is used for various applications such as an illumination device for a scanner. Can be applied.

  The aspect of the present invention is not limited to the individual embodiments described above, and includes various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Projection type display apparatus, 15 screen, 20 projection apparatus, 25 projection optical system, 30 spatial light modulator, 35 relay optical system, 37 homogenization optical system, 40 illumination apparatus, 50 optical element, 51 lens array, 51a unit lens , 52 field lens, condenser lens, 57 hologram recording medium, 60 irradiation device, 61 light source device, 62 light source, 66 first light source, 67 second light source, 68 third light source, 70 scanning device, 71 first reflection device, 71a Reflective member, 71b shaft member, 71c first driving device, 71d inclined surface, 71e first shaft portion, 71f second shaft portion, 71g connecting portion, 72 first reflecting surface, 73 second reflecting device, 73a reflecting member, 73b Shaft member, 73c Second driving device, 74 Second reflecting surface, 75 Controller, 76 First member, 77 Second member, 77 a mirror surface, 78 first support tool, 79 second support tool, 90 irradiation device, 91 light source, 92 light source, 95 scanning device, 96 reflection device, 97 deflection element, 99 optical element

Claims (13)

A drive unit that rotationally drives the rotary shaft;
A first member that passes through the rotating shaft and is fixed to the rotating shaft;
A second member disposed on the first member and penetrating the rotating shaft together with the first member and fixed to the rotating shaft;
The surface of the second member opposite to the first member side is a mirror surface that reflects incident light, and the normal direction of the mirror surface is inclined from the axial direction of the rotation axis.   The optical scanning device according to claim 1, further comprising: a first support member that is joined to a part of the mirror surface of the second member and fixes the second member to the rotation shaft. The area of the upper surface of the first support is smaller than the area of the mirror surface,
The optical scanning device according to claim 2, wherein the first support is disposed at a rotation center position on the mirror surface.   The optical scanning device according to claim 2, wherein the first support is joined on the mirror surface.   The optical scanning device according to claim 2, wherein the first support is joined to an inner surface of a recess formed along the mirror surface of the second member.   The optical scanning device according to claim 2, wherein an upper surface of the first support is a mirror surface.   The optical scanning device according to claim 1, further comprising: a second support that fixes the first member to the rotation shaft on the opposite side of the first member to the second member.   The optical scanning device according to claim 1, wherein the mirror surface of the second member and a surface on the opposite side thereof are non-parallel.   9. The optical scanning device according to claim 1, wherein the mirror surface is a polished surface or a metal-deposited surface.   The optical scanning device according to claim 1, further comprising a controller that controls a rotational speed or a rotational frequency of the rotating shaft with respect to the driving unit. An optical scanning device according to any one of claims 1 to 10,
An optical module comprising: an optical element capable of diffusing the coherent light reflected by the optical scanning device to the entire area within a predetermined area. An optical element capable of diffusing the coherent light incident on each position to the entire area within a predetermined area;
An illumination device that irradiates the optical element with the coherent light so that coherent light scans the surface of the optical element,
The irradiation device includes:
A light source that emits coherent light;
An illumination device comprising: the optical scanning device according to any one of claims 1 to 10, wherein a scanning direction of the coherent light emitted from the light source is changed to scan the surface of the optical element. apparatus. A spatial light modulator disposed at a position overlapping the predetermined region and illuminated by the illumination device according to claim 12 to generate a light modulation image;
A projection optical system that projects the light-modulated image onto a projection member.

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