WO2017213069A1 - Light propagation device, display device and lighting device - Google Patents

Abstract

Provided is a light propagation device capable of flexibly varying the light volume of a branch destination, when incident light branches into a plurality of branches and is emitted. This light propagation device is characterized by comprising: an input port into which light enters; an output-side port that includes a plurality of output ports which emit light to the outside; a MEMS light switch that has a tilt mirror controlled to a tilt angle corresponding to the drive voltage, and that optically joins the input port and one of the output-side ports in accordance with the tilt angle of the tilt mirror; a setting reception unit that receives a setting relating to the light volume of the output light; a light volume control unit that sets, on the basis of the setting relating to the light volume, a switching schedule indicating the allocation period of each of the output-side ports for each single cycle; and a drive control unit that outputs a drive voltage on the basis of the switching schedule.

Description

Light propagation device, display device, and illumination device

The present invention relates to a light propagation device, a display device, and an illumination device based on a light propagation technique that divides incident light into a plurality of light beams and emits the light.

As shown in FIG. 10, light emitted from a light source 310 such as a laser light source is incident on a single optical fiber 320 and is split into a plurality of (340a to 340n) optical fibers and output ports. Conventionally, an optical splitter has been widely used. The optical splitter branches incident light according to a predetermined branching ratio. For example, in the case of an optical splitter that evenly splits incident light, equal amounts of light are simultaneously emitted from branch destination optical fibers or the like (340a to 340n).

In recent years, as described in Patent Document 1, an optical switch capable of switching a branch destination is also used. The optical switch is an optical element that switches incident light to one of a plurality of branch destinations. For example, for an optical fiber or the like (340a to 340n) of a branch destination, an outgoing light can be arbitrarily controlled by control of a separately provided control unit. It can be switched sequentially at the timing.

Japanese Patent No. 5087087

When an optical splitter is used as the optical branching element 330, light having a light quantity according to a predetermined branching ratio can be obtained simultaneously. Further, when an optical switch is used as the optical branching element 330, almost all of the incident light quantity is emitted from the optical fiber or the like selected and switched uniformly.

Thus, when the light is branched using the light branching element 330, it has not been considered to change the light quantity at the branch destination. If the amount of light at the branch destination can be changed flexibly, the application targets of the optical branch element 330 can be diversified, and the utility value of the optical branch element 330 can be increased.

Therefore, an object of the present invention is to provide a light propagation device, a display device, and an illumination device that can flexibly change the amount of light at the branch destination when the incident light is branched into a plurality of light beams.

In order to solve the above-described problems, an optical propagation device according to a first aspect of the present invention includes an input port for entering light, an output side port including a plurality of output ports for emitting light to the outside, and a drive voltage. A MEMS optical switch having a tilt mirror controlled to a corresponding tilt angle, and optically coupling one of the input port and the output side port according to the tilt angle of the tilt mirror; A setting acceptance unit that accepts settings relating to the light amount, a light amount control unit that sets a switching schedule indicating an allocation period of each port of the output side port for each cycle based on the setting relating to the light amount, and a basis based on the switching schedule And a drive control unit that outputs the drive voltage.
Here, the output port may include an off port that does not output light to the outside.
At this time, it is preferable that the setting receiving unit receives a setting relating to the attenuation amount of light, and the light amount control unit sets a longer period to be allocated to the off-port as the set attenuation amount is larger.
Alternatively, the setting reception unit may receive a setting relating to the light amount for each output port, and the light amount control unit may set the ratio of the allocation period to be larger for an output port having a larger set light amount.
In addition, when the tilt control mirror is changed from the first tilt angle to the second tilt angle, the drive control unit changes the first signal corresponding to the first tilt angle to the second signal corresponding to the second tilt angle. When switching, an intermediate voltage larger than the first signal and smaller than the second signal can be output for an intermediate voltage application time.
At this time, the intermediate voltage is a driving voltage having the second tilt angle at the maximum amplitude of the tilt mirror during a transient response, and the intermediate voltage application time is a time until the tilt mirror reaches the maximum amplitude. can do.
In order to solve the above problems, a display device according to a second aspect of the present invention includes the above-described light propagation device and a light emission window corresponding to the output port.
In order to solve the above problems, an illumination device according to a third aspect of the present invention includes the above-described light propagation device and a light diffusion fiber connected to the output port.

According to the present invention, it is possible to flexibly change the light amount at the branch destination when the incident light is branched and emitted.

It is a block diagram which shows the structure of the light propagation apparatus which concerns on this embodiment. It is a figure which shows the example of a switching schedule. It is a figure which shows the example from which a switching schedule differs. It is a figure which shows the example from which a switching schedule differs. It is a figure which shows the example which changes a switching schedule with multiple periods. It is a schematic diagram which shows the change angle of a tilt mirror. It is a figure which shows the example of application of a general drive voltage. It is a figure which shows the example of application of the drive voltage in this embodiment. It is a figure which shows the example of application of this invention. It is a figure which shows the optical element which branches the incident light from a light source into multiple pieces.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of the light propagation device 100 according to the present embodiment. The light propagation device 100 is a device that divides incident light into a plurality of light beams and emits the light, and uses a MEMS optical switch 120 as a light branch element. The MEMS optical switch 120 is an optical switch to which MEMS (Micro Electro Mechanical Systems) technology is applied, and is smaller, faster and more durable than a mechanical optical switch.

As shown in FIG. 1, the optical propagation device 100 includes an input port 110, a plurality of output ports 130, an off port 132, and a control unit 140 in addition to the MEMS optical switch 120.

The input port 110 is a light incident port, and inputs light from the light source 210 via the optical fiber 220 or the like. For example, a visible light laser light source can be used as the light source 210. However, an LED light source, a lamp, or the like may be used. Further, it may emit invisible light such as infrared light.

The MEMS optical switch 120 includes a tilt mirror 121 and a drive electrode 122. The tilt mirror 121 is disposed at a position where light input from the input port 110 is guided to the reflection surface. The drive electrode 122 adjusts the tilt angle of the tilt mirror 121 according to the input drive voltage. Thereby, the direction of reflected light can be changed. In the present embodiment, description will be made by taking one axis as an example, but two axes may be used.

The plurality of output ports 130 and off ports 132 are arranged at positions where light input to the input port 110 is irradiated by reflection of the tilt mirror 121. The output port 130 and the off port 132 are collectively referred to as an output side port 134.

The tilt angle of the tilt mirror 121 and the position of each port (output boat 130, off-port 132) of the output side port 134 are associated in advance in the light propagation device 100, and the tilt angle of the tilt mirror 121 is changed. Any of the output ports 134 can be irradiated with the light input to the input port 110. The output side port 134 that is the irradiation destination is optically coupled to the input port 110.

The output port 130 is a light emission port, and when the light input to the input port 110 is irradiated, the light is output to the outside through the optical fiber 230 or the like. On the other hand, the off port 132 does not output the light to the outside even when the light input to the input port 110 is irradiated. The off port 132 may be disposed between the adjacent output ports 130, or a plurality of off ports 132 may be provided. The off-port 132 may be configured with a wall that simply shields light.

The control unit 140 includes a setting reception unit 141, a light amount control unit 142, and a drive control unit 143. The setting accepting unit 141 can be configured by a switch, an operation key, and the like, and accepts settings related to the amount of light output from the output port 130, such as the amount of light attenuation and the amount of light for each output port, from the user.

The light quantity control unit 142 can be configured by an arithmetic device, a memory, etc., and sets the irradiation destination switching schedule of the tilt mirror 121 of the MEMS optical switch 120 according to the setting relating to the light quantity received by the setting reception unit 141. The light amount control unit 142 sets a longer period to be assigned to the off-port 130 as the set attenuation amount is larger, and sets a larger ratio of the assigned period as the output port has a larger set light amount. The switching schedule indicates the allocation period of each output side port for each cycle.

The drive control unit 143 can be configured by a voltage output device or the like, and outputs a drive voltage to the drive electrode 122 according to a switching schedule.

Next, the operation of the light propagation device 100 in this embodiment will be described. Here, it is assumed that the output port 130 includes four output ports 1 to 4.

The switching schedule set by the light amount control unit 142 defines the irradiation timing in one cycle for each of the output side ports 134. For example, a switching schedule as shown in FIG. 2 will be described as an example.

In the example of this figure, W1 is a period for irradiating the output light of the reflected light of the tilt mirror 121, W2 is a period for irradiating the output port 2, W3 is a period for irradiating the output port 3, and the output port 4 is irradiated. The period is set to be W4, and W1, W2, W3, and W4, which are continuous with the same period length, are set to be repeated for a plurality of periods. Irradiation to the off-port 132 is not performed.

Note that each cycle is a time that does not cause the human eye to flicker when the time is a blinking cycle. Specifically, it is preferably shorter than about 33 msec (30 Hz), for example, about 16 msec (62.5 Hz).

In this case, each output port repeats blinking at a cycle where flicker is not felt, so that the human eye feels that the lighting state is continuous. Specifically, since the lighting period lengths of the output ports are equal, assuming that the light amount of light input to the input port 110 is 100%, each output port outputs light of 25% light amount simultaneously. As perceived. Loss is not considered.

Further, as shown in FIG. 3A, when a period WO for irradiating the off-port 132 within one cycle period is set, and W1, W2, W3, W4, and WO are continuous with the same period length, each output port From the above, it is recognized that 20% of light is output at the same time.

Further, as shown in FIG. 3 (b), if the WO is set long, for example, a period of 40% of one cycle and W1, W2, W3, and W4 are the same period length, each output port It is recognized that 15% light is output at the same time.

That is, the amount of light at each output port can be uniformly changed by adjusting the period WO irradiated to the off-port 132 in one cycle and evenly assigning the remaining period to each output port.

In this case, since the light quantity of each output port becomes equal, it can be referred to as a uniform light quantity mode. In the uniform light amount mode, the period WO is set by the amount of light attenuation.

For example, when the “attenuation amount 0”, “medium attenuation amount”, and “attenuation amount large” switches are prepared in the setting reception unit 141 and the light amount control unit 142 selects “attenuation amount 0”, FIG. When the switching schedule as shown in FIG. 3 is set and “medium attenuation” is selected, the switching schedule as shown in FIG. 3A is set and when “high attenuation” is selected. Thus, an operation for setting a switching schedule as shown in FIG. In this case, since the light quantity control unit 142 does not need to perform complicated control, it can be realized by a logic circuit, for example, and can be configured simply. Of course, the period of WO can be set arbitrarily, and the attenuation can be set flexibly.

The period allocated to each output port may not be equal. For example, as shown in FIG. 4, the period of W1 allocated to the output port 1 is 50% of one cycle, the period of W2 allocated to the output port 2 is 25%, and the period of WO allocated to the off-port is 25%. Then, it is recognized that 50% light amount is output from the output port 1 and 25% light amount is output from the output port 2. At this time, no light is output from the output port 3 and the output port 4.

That is, the amount of light can be changed for each output port by adjusting the period allocated to each port of the output side port 134 in one cycle. In this case, since the light quantity ratio of each output port can be changed arbitrarily, it can be referred to as a light quantity ratio change mode. At this time, the WO period may be set to 0%.

For example, a key for designating the light amount ratio of each output port and a key for designating the attenuation amount are prepared in the setting reception unit 141, and the light amount control unit 142 assigns the off port based on the designation of the attenuation amount. The WO period is set, and the remaining period can be operated by setting a switching schedule in which the period is assigned to each output port based on the designation of the light quantity ratio. When only one output port to which a period is assigned is set, only that output port can be illuminated and the amount of light can be changed arbitrarily.

As shown in FIG. 5, the light quantity of each output port may be changed for each of a plurality of cycles. In the example shown in FIG. 5, in the first N1 period, the light quantity of the output port 1 is 50%, the light quantity of the output port 2 is 10%, the light quantity of the output port 3 is 10%, and the light quantity of the output port 4 is 0. %. In the next N2 cycle, the light amount of the output port 1 is 0%, the light amount of the output port 2 is 50%, the light amount of the output port 3 is 10%, the light amount of the output port 4 is 10%, and the N1 cycle. , N2 period, N3 period, and N4 period, the light quantity of each output port is set to be different. N1, N2, N3, N4... May be the same number of cycles or different.

In this way, by changing the light amount of each output port for each cycle of a plurality of cycles, for example, the brightest output port can be moved sequentially, or the output port that is turned off can be moved sequentially, It is possible to realize a light quantity change that is more varied. As shown in FIG. 5, the light quantity of each output port may be set different for each period of N1, N2, N3, N4, and so on, but each output port in each period May be set so that the amount of light is the same.

Next, the drive voltage Va (t) output from the drive control unit 143 will be described. Here, as shown in FIG. 6, a case where the drive voltage Va (t) is changed to change the tilt mirror 121 from a certain angle by θ is taken as an example. As described above, the output ports 134 and the tilt angle of the tilt mirror 121 are associated with each other in the light propagation device 100.

Since the angle of the tilt mirror 121 depends on the drive voltage Va (t) applied to the drive electrode 122, the drive voltage Va (t) corresponding to the angle before the change of the tilt mirror 121 is V0, and the angle when changed by θ. A driving voltage Va (t) corresponding to is V1.

For example, as shown in FIG. 7, when the drive voltage Va (t) is changed directly from V0 to V1, it takes time until the tilt mirror 121 vibrates and converges to the angle θ and stabilizes in a transient response. This is because the tilt mirror 121 has a mechanical resonance frequency and resonates at that frequency.

For this reason, in this embodiment, as shown in FIG. 8, before changing the drive voltage Va (t) from V0 to V1, the intermediate voltage V2 is passed through only the time t2. That is, when changing the tilt mirror 121 from the first tilt angle to the second tilt angle, the drive control unit 143 corresponds to the second tilt angle from the drive voltage V0 that is the first signal corresponding to the first tilt angle. When switching to the driving voltage V1, which is the second signal, an intermediate voltage V2 that is larger than the first signal and smaller than the second signal is output for the intermediate voltage application time (time t2). The intermediate voltage V2 being larger than the first signal and smaller than the second signal means that the intermediate voltage V2 is an arbitrary voltage value within the range exceeding the first signal and less than the second signal, and is not necessarily the first signal. And the intermediate voltage value between the second signal and the second signal.

Here, it is assumed that V2 and t2 have a relationship that becomes the maximum amplitude of the angle θ after time t2 as a transient response when the drive voltage Va (t) is changed from V0 to V2. . That is, the drive voltage Va (t) is changed to V1 at the moment when V2 is applied as the drive voltage Va (t) and the angle θ has the maximum amplitude. Thereby, the vibration of the tilt mirror 121 can be prevented and can be quickly stabilized at the angle θ. Note that V2 and t2 on mounting are determined theoretically and experimentally.

The light propagation device 100 of the present embodiment has been described above, but the present invention can be applied to various devices. For example, as shown in FIG. 9A, a light emitting window 162 corresponding to the output port 130 is formed on the light output side of the output port 130 so that the display device 160 can be used. As shown in FIG. 9B, the light emission windows 162 may be arranged in both the horizontal direction and the vertical direction. In this way, the display device 160 can display characters and symbols.

Further, instead of the normal optical fiber 230, as shown in FIG. 9C, a light diffusing fiber 232 capable of emitting light from the side surface is connected to the output port 130 so that it can be used as the lighting device 170. it can.

DESCRIPTION OF SYMBOLS 100 Light propagation apparatus 110 Input port 120 MEMS optical switch 121 Tilt mirror 122 Drive electrode 130 Output port 132 Off port 134 Output side port 140 Control part 141 Setting reception part 142 Light quantity control part 143 Drive control part 160 Display apparatus 162 Light emission window 232 Light Diffusing fiber 170 Illuminating device 210 Light source 220 Optical fiber 230 Optical fiber 310 Light source

Claims (8)

1. An input port for incident light;
   An output side port including a plurality of output ports for emitting light to the outside;
   A MEMS optical switch having a tilt mirror controlled to an inclination angle corresponding to a driving voltage, and optically coupling either the input port or the output side port according to the inclination angle of the tilt mirror;
   A setting reception unit for receiving settings relating to the amount of light to be output;
   A light amount control unit that sets a switching schedule indicating an allocation period of each port of the output side port for each cycle based on the setting relating to the light amount;
   A drive control unit that outputs the drive voltage based on the switching schedule;
   An optical propagation device comprising:
2. The light propagation apparatus according to claim 1, wherein the output side port includes an off port that does not output light to the outside.
3. The setting reception unit receives a setting related to the amount of attenuation of light,
   The light propagation device according to claim 2, wherein the light amount control unit sets a longer period to be assigned to the off-port as the set attenuation amount is larger.
4. The setting accepting unit accepts a setting relating to a light amount for each output port,
   4. The light propagation device according to claim 2, wherein the light amount control unit sets a larger ratio of the allocation period for an output port having a larger set light amount. 5.
5. The drive control unit
   When the tilt mirror is changed from the first tilt angle to the second tilt angle, the first signal is changed when the first signal corresponding to the first tilt angle is switched to the second signal corresponding to the second tilt angle. 5. The optical propagation device according to claim 1, wherein an intermediate voltage that is larger than the second signal is output for an intermediate voltage application time.
6. The intermediate voltage is a drive voltage that becomes the second tilt angle at the maximum amplitude of the tilt mirror during a transient response,
   6. The light propagation device according to claim 5, wherein the intermediate voltage application time is a time until the tilt mirror reaches a maximum amplitude.
7. The light propagation device according to any one of claims 1 to 6,
   A light emitting window corresponding to the output port;
   A display device comprising:
8. The light propagation device according to any one of claims 1 to 6,
   A light diffusing fiber connected to the output port;
   An illumination device comprising:

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