JP2003149567A - Laser light source unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a speckle noise by moving a reflector which collimates laser light into parallel light without adding any special optical element for reducing the speckle noise of laser light. SOLUTION: The laser light 14 emitted from an optical fiber 13 is made to impinge on the reflecting surface 22 of the reflector 21 while being diverged, and its initial divergence angle is varied to obtain laser light 17 which is close to, for example, parallel light. The reflector 21 is moved by a moving means 16 and then, when the laser light 17 reflected by the reflecting surface 22 is observed while the reflection state of the laser light 14 is changed, the state changes with time so that it becomes hard to view the speckle noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser light source suitable for a light source for a consumer display, which reduces speckle noise when changing a divergence angle of laser light using a reflector and converting it into parallel light. Regarding the device.

[0002]

2. Description of the Related Art A conventional method for reducing speckle noise from a laser light source will be described. It is known that speckle noise is generated due to good coherence of laser light, and by disturbing it, the speckle noise is reduced. First, JP-A-11-1019
In No. 25, the speckle noise can be reduced by further reducing the spatial coherence. This will be described with reference to the schematic diagram of FIG.

As shown in FIG. 14, after a laser beam 142 generated by a laser light source 141 is randomly incident on a means 143 for disturbing the phase, the laser beam 14 with the disordered phase is introduced.
4 is incident on the bundle fiber 145. this is,
As shown in FIG. 15, since the lengths of the respective fibers 152 constituting the bundle fiber 151 are different, the output lights from the respective fibers 152 become incoherent with each other, so that speckle noise can be reduced.

Further, in Japanese Unexamined Patent Publication No. 6-208089, “Speckle-free display device using coherent light”, speckle noise is reduced by reducing temporal coherence. As shown in FIG. 16, the coherent light 162 from the coherent light source 161 enters the diffusing element 163. The movable means 164 rotates or vibrates the diffusion element 163.

Light 165 diffused by the diffusing element 163
Enters the image forming device 166, and its output light 167 is focused on the spatial light modulator 168. The image 169 modulated by the spatial light modulator 168 is displayed on the viewing surface 170.

By rotating the diffusing element 163,
The interference pattern can be split and moved on the viewing surface 170. That is, due to the integration effect of human eyes, it becomes difficult to visually recognize, and speckle noise can be reduced.

However, in the above description, optical elements such as a bundle fiber and a diffusing element are added in order to reduce speckle noise, which causes problems such as a decrease in light utilization efficiency and an increase in cost. That is, in order to reduce the speckle noise, a new optical element is incorporated, so that a problem arises that an optical element other than the original optical system is required.

[0008]

In order to reduce the speckle noise of the laser light of the above-mentioned conventional laser light source device, it is necessary to add a dedicated optical element, which causes a problem in terms of cost and utilization efficiency. there were.

An object of the present invention is to provide a laser light source device for reducing speckle noise using a reflector for collimating laser light without adding a special optical element for reducing speckle noise of laser light. To get.

[0010]

In order to solve the above-mentioned problems, a laser light source device of the present invention is a laser generator for emitting a laser beam, an optical fiber for propagating the laser beam, and an emission from the optical fiber. It is characterized by comprising a conversion means for converting the divergence angle of the laser light to be generated and a reduction means for moving the conversion means to reduce speckle noise.

Further, a laser generator for emitting a laser beam, an optical fiber for propagating the laser beam, and a laser beam emitted from the optical fiber are directly or via a diffusing element applied to a reflector to spread the laser beam. And a reducing unit that moves at least one of the reflector and the diffusing element to reduce speckle noise.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration diagram for explaining a first embodiment of the present invention. In FIG. 1, a laser beam 12 emitted from a laser generator 11 enters an optical fiber 13. The laser light 14 propagated through the optical fiber 13 enters the reflector device 15. The reflector device 15 receives the power from the movable means 16 to perform rotation or amplitude movement.

In the reflector device 15, the optical fiber 13
By reflecting the laser beam 14 emitted from, the laser beam diameter and the divergence angle are converted, and the laser beam 17 is emitted. Since the diffused state of the emitted laser light 17 changes temporally due to the movement of the reflector device 15, it is difficult to visually recognize speckle noise, and noise can be reduced.

Now, the optical fiber 13 and the reflector device 15 will be described more specifically with reference to FIG. The reflector device 15 includes a reflector 21 and a reflecting surface 22. The emitting end of the optical fiber 13 and the reflecting surface 22 of the reflector 21 are arranged to face each other.

Laser light 1 emitted from the optical fiber 13
4 spreads and hits the reflecting surface 22 of the reflector 21, and the initial spreading angle is changed to obtain the laser light 17 in a state close to parallel light, for example.

Since the reflector 21 is moved by the movable means 16, the reflection state of the laser light 14 changes. This light is reflected by the reflection surface 22 and laser light 17
When observed, the speckle noise becomes difficult to visually recognize because the state changes with time.

FIG. 3 is a block diagram for explaining a concrete example of the movable means 16. In this example, the rotation device 161
The reflector 21 is attached to the rotary shaft 31 and is rotated as shown by an arrow in the figure. It is not necessary to polish the reflecting surface 22 with high precision, and a slightly non-uniform state remains in the rotating direction, so that the reflecting state changes, and speckle noise when the laser beam 17 is observed can be reduced. A motor can be considered as the rotating device 161, for example.

FIG. 4 is for explaining another specific example of the movable means 16 of FIG. In this example, the reflector 21 is oscillated using the vibration device 162,
(A)-(c) shows the state of amplitude. That is, the operating rod 41 of the vibration device 162 of FIG. 4A is operated in the arrow direction to move the reflector 21 in the arrow direction.
When reaching the position shown in (b), the reflector 21 is moved in the direction of the arrow in (c). The following (a) to (c) are repeated to perform the amplitude operation on the reflector 21.

By oscillating the reflector 21, the reflector 2 of the laser light 14 emitted from the optical fiber 13
The irradiation position on 1 changes. Therefore, the reflector 21
Since the direction of the laser beam 17 reflected by (4) changes temporally between (a) and (c) of FIG. 4, it is possible to reduce speckle noise. As the vibration device 162,
For example, a piezoelectric element can be considered.

FIG. 5 is a block diagram for explaining the second embodiment of the present invention, in which the same components as those in FIG. 1 are designated by the same reference numerals. In this embodiment, a diffusing element is added to the reflector device 15.

In FIG. 5, the laser beam 12 emitted from the laser generator 11 is incident on the optical fiber 13. The laser light 14 propagated through the optical fiber 13 enters the diffusion / reflector device 51. The diffusing / reflecting device 51 receives power from the movable means 16 to perform rotation or amplitude movement.

In the diffusing / reflecting device 51, by reflecting the laser light 14 emitted from the optical fiber 13,
The laser beam diameter and the divergence angle are converted, and the laser light 17 is emitted. Since the diffused / reflector device 51 moves, the diffused state of the emitted laser light 17 changes with time, so that speckle noise is less visible and noise can be reduced.

Here, referring to FIG. 6, the optical fiber 13 of FIG.
A specific example will be described below in which the reflector of the diffusion / reflector device 51 is moved.

Laser light 1 emitted from the optical fiber 13
Reference numeral 4 denotes a diffusing element 61, where the laser light 14 is reflected and diffused to irradiate the reflecting surface 22 of the reflector 21 and is reflected here. The reflected laser light is emitted as laser light 17 in a state close to parallel light.

Since the reflector 21 is moved by the movable means 16, the reflection state of the laser beam 14 changes, and when the laser beam 17 reflected by the reflection surface 22 is observed, the state changes with time. Therefore, it becomes difficult to visually recognize speckle noise.

In this example, the optical fiber 13 is installed on the back side of the reflecting surface 22, but it does not matter if it is at the position corresponding to the diffusing element 61, so it does not have to be at the center and is installed on the reflecting surface 22 side. Alternatively, a transmissive diffusion element may be irradiated.

FIG. 7 is a configuration diagram for explaining a specific example of the movable means 16 of FIG. This example shows movable means 1
6 using the rotating device 161 as the reflector 21 of FIG.
Is rotating.

Here, it is not necessary to polish the reflecting surface 22 of the reflector 21 with high precision, and a slight non-uniform state remains in the rotating direction, so that the reflecting state changes due to rotation, and the specs when observing the laser beam 17 are specified. It is possible to reduce the noise.

FIG. 8 is a configuration diagram for explaining another specific example of the movable means 16 of FIG. In this example, a vibrating device 162 is used as the movable means 16, and the reflector 21 of FIG. 6 is amplitude-moved.

That is, the reflector 21 is moved in the direction of arrow A in FIG. 8 (a) to move from the position (b) to this time (c).
Amplitude movement is made to move in the direction of arrow B. As a result, the irradiation position of the laser light 14 emitted from the optical fiber 13 on the reflector 21 changes. Therefore, the direction of the laser beam 17 reflected by the reflector 21 is (a) in FIG.
Since it changes from the value of (c) to the value of (c), it is possible to reduce speckle noise.

Next, with reference to FIG. 9, a specific example will be described in which the diffusing element is moved by using the moving means 16 of FIG.

In this example, the diffusing element 61 arranged in the reflector 21 constituting the diffusing / reflecting device 51 is rotated by the rotating shaft 91 of the rotating device 161. The rotating shaft 91 is formed of a cylindrical glass that transmits laser light, and the output end of the optical fiber 13 is arranged therein. The optical fiber 13 is fixed.

Also in this case, it is not necessary to polish the reflecting surface of the diffusing element 61 with high precision, and a slightly non-uniform state remains in the rotating direction, so that the reflecting state changes due to rotation, and the laser beam 1
It is possible to reduce speckle noise when observing No. 7.

FIG. 10 illustrates another specific example in which the diffusing element is moved by using the moving means 16 shown in FIG.

In this example, the diffusing element 61 arranged in the reflector 21 constituting the diffusing / reflecting device 51 is
The operating rod 101 of the vibrating device 162 causes amplitude movement. The operating rod 101 is formed of glass on a cylinder that transmits laser light, and the output end of the optical fiber 13 is arranged therein. The optical fiber 13 is fixed.

That is, the diffusing element 61 is moved in the direction of arrow A in FIG. 10 (a) to move from the position (b) to this time (c).
Amplitude movement is made to move in the direction of arrow B. As a result, the irradiation position of the laser light 14 emitted from the optical fiber 13 on the diffusion element 61 changes. Therefore, the diffusion element 6
Since the direction of the laser beam 17 reflected at 1 changes from (a) to (c) of FIG. 10, the speckle noise can be reduced also in this case.

FIG. 11 is a block diagram for explaining the third embodiment of the present invention, and specifically shows only the optical fiber 13 and the vicinity of the reflector device 15. In this embodiment, the optical fiber 13 is connected to the reflector 2.
6 is different from that shown in FIG. 6 in that the reflecting surface 22 is partially removed and installed at a position away from the center.

When the reflector 21 is moved, since a part of the reflecting surface 22 in the movable range is cut, a non-moving reflecting surface is installed in a portion corresponding to the range.

FIG. 12 shows a state in which the reflecting surface 22 of FIG. 11 is viewed from the front. The shaded portion of FIG. 12 (a) enables the reflector 21 to perform the amplitude movement indicated by an arrow A in FIG. The cut 121 is the cut 12 shown in FIG.
2 shows a state in which two are formed respectively.

As a result, even when the arrangement of the optical fiber 13 is displaced from the center position, the non-reflecting range can be reduced when the optical fiber 13 is moved, so that the utilization efficiency is not deteriorated and the reflector 21 is prevented.
Can be moved.

As the power of the movable means in each of the above-mentioned embodiments, in addition to those of the motor and the piezoelectric element, FIG.
As shown in, a fan 132 may be attached to the rotating shaft 131 to use cooling air. Usually, a light source is provided with a fan for blowing air in order to suppress the temperature rise of the optical element, and in this case, by providing a rotating mechanism utilizing the blowing air, there is an advantage that new power is unnecessary.

As described above, according to each embodiment of the present invention, speckle noise can be reduced without adding a special optical element.

[0043]

As described above, according to the laser light source device of the present invention, by moving the reflector for converting the laser light into parallel light without adding a special optical element, the spec. It is possible to reduce noise.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining a first embodiment of the present invention.

FIG. 2 is a configuration diagram for specifically explaining a main part of FIG.

FIG. 3 is a configuration diagram for explaining a second embodiment of the present invention.

FIG. 4 is a configuration diagram for specifically explaining a main part of FIG.

FIG. 5 is a configuration diagram for explaining a second embodiment of the present invention.

6 is a configuration diagram for specifically explaining a main part of FIG.

FIG. 7 is a configuration diagram for explaining a specific example in which a reflector is moved using the moving unit in FIG.

FIG. 8 is a configuration diagram for explaining another specific example in which the reflector is moved by using the moving unit in FIG.

FIG. 9 is a configuration diagram for explaining a specific example in which a diffusing element is moved using the moving unit in FIG.

10 is a configuration diagram for explaining another specific example in which the diffusing element is moved by using the moving unit in FIG.

FIG. 11 is a configuration diagram for explaining a third embodiment of the present invention.

FIG. 12 is a front view for explaining a state in which the reflection surface of FIG. 11 is viewed from the front.

FIG. 13 is a configuration diagram for explaining another specific example of the movable means used in each embodiment of the present invention.

FIG. 14 is a configuration diagram for explaining a conventional laser light source device.

FIG. 15 is an explanatory diagram for explaining the Pandle fiber of FIG. 14;

FIG. 16 is a configuration diagram for explaining another conventional laser light source device.

[Explanation of symbols]

11 ... Laser generator 13 ... Optical fiber 15 ... Reflector device 16 ... Movable means 21 ... Reflector 22 ... Reflective surface 161 ... Rotating device 162 ... Vibration device 31, 91 ... Rotating shaft 41, 101 ... Operation rod 51 ... Diffusion / reflector device 61 ... Diffusion element

Continued front page    (72) Inventor Masaki Tsuchida             8th Shinsugita Town, Isogo Ward, Yokohama City, Kanagawa Prefecture             Ceremony company Toshiba Yokohama office (72) Inventor Kaji Nobuaki             8th Shinsugita Town, Isogo Ward, Yokohama City, Kanagawa Prefecture             Ceremony company Toshiba Yokohama office F-term (reference) 2H041 AA08 AA12 AA23 AB12 AC04                       AC08                 2H087 KA29 TA03 TA04 TA08

Claims (8)

[Claims] 1. A laser generator that emits laser light, an optical fiber that propagates the laser light, a conversion unit that converts the spread angle of the laser light emitted from the optical fiber, and a speckle that moves the conversion unit. A laser light source device, comprising: a reduction unit that reduces noise. 2. The laser light source device according to claim 1, wherein the conversion means is a reflector that converts a spread angle of incident laser light. 3. The laser light source device according to claim 1, wherein the conversion means is a reflector that converts a divergence angle of laser light incident through a diffusion element. 4. A laser generator for emitting a laser beam, an optical fiber for propagating the laser beam, a laser beam emitted from the optical fiber, and a divergence angle of the laser beam applied to a reflector directly or via a diffusion element. A laser light source device, comprising: a conversion unit that converts the light and a reduction unit that moves at least one of the reflector and the diffusion element to reduce speckle noise. 5. The means for moving the reflector or the diffusing element is a rotating mechanism.
The laser light source device described. 6. The laser light source device according to claim 4, wherein the means for moving the reflector or the diffusing element is a mechanism for moving the reflector or the diffusing element back and forth in the reflection direction of the reflector. 7. The laser light source device according to claim 5, wherein the mechanism for rotating the reflector or the diffusing element uses the wind of a cooling fan. 8. A mirror in which an emitting end of the optical fiber is arranged in a reflecting surface of the reflector, a contacting portion of the reflector is transparent or cut, and is fixed to a portion other than the installed end of the optical fiber emitting end. The laser light source device according to claim 4, wherein the laser light source device is installed.