JP7042493B2 - Light propagation device, display device and lighting device - Google Patents

Description

The present invention relates to a light propagation device, a display device, and a lighting device based on a light propagation technique that splits and emits incident light into a plurality of pieces.

As shown in FIG. 10, as an optical branching element 330 in which light emitted from a light source 310 such as a laser light source is incident on one optical fiber 320 and branched into a plurality of (340a to 340n) optical fibers and output ports. Conventionally, optical splitters have been widely used. The optical splitter splits the incident light according to a predetermined branching ratio. For example, in the case of an optical splitter that uniformly splits incident light, the same amount of light is simultaneously emitted from the optical fiber or the like (340a to 340n) at the branch destination.

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

Japanese Patent No. 5087087

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

As described above, when the light is branched by using the optical branching element 330, it is not considered to change the amount of light at the branching destination. If the amount of light at the branch destination can be flexibly changed, the application target of the optical branch element 330 will 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 an optical propagation device, a display device, and a lighting device that can flexibly change the amount of light at the branch destination when the incident light is branched into a plurality of emitted light.

In order to solve the above problems, the present invention
(1) An input port that receives light and
An output port that includes multiple output ports that emit light to the outside,
A MEMS optical transistor having a tilt mirror controlled to a tilt angle corresponding to a drive voltage and optically coupling any of the input port and the output side port according to the tilt angle of the tilt mirror.
A setting reception unit that accepts settings related to the amount of light to be output,
A light amount control unit that sets a switching schedule indicating the allocation period of each port of the output side port for each cycle based on the setting regarding the light amount.
A drive control unit that outputs the drive voltage based on the switching schedule is provided.
The output side port includes an off port that does not output light to the outside.
The setting receiving unit receives the setting regarding the amount of light attenuation, and receives the setting.
The light amount control unit is characterized in that the larger the set attenuation amount is, the longer the period allocated to the off-port is set .
(2) The setting receiving unit receives the setting regarding the amount of light for each output port, and receives the setting.
The light propagation device according to (1) above, wherein the light amount control unit sets a larger ratio of the allocation period as the set output port has a larger light amount.
(3) The drive control unit is
When the tilt mirror is changed from the first tilt angle to the second tilt angle, the first signal is used when switching from the first signal corresponding to the first tilt angle to the second signal corresponding to the second tilt angle. The light propagation apparatus according to (1) or (2) above, wherein an intermediate voltage larger than or smaller than the second signal is output for an intermediate voltage application time.
(4) The intermediate voltage is a drive voltage that becomes the second tilt angle at the time of the maximum amplitude of the tilt mirror at the time of transient response.
The light propagation apparatus according to (3), wherein the intermediate voltage application time is a time until the tilt mirror reaches the maximum amplitude.
(5) The light propagating device according to any one of (1) to (4) above,
A light emitting window corresponding to the output port and
A display device, characterized by being equipped with
(6) The light propagating device according to any one of (1) to (4) above,
With the optical diffusion fiber connected to the output port,
Lighting equipment characterized by being equipped with
I will provide a.

According to the present invention, when the incident light is branched into a plurality of pieces and emitted, the amount of light at the branch destination can be flexibly changed.

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 the switching schedule. It is a figure which shows the example of a different switching schedule. It is a figure which shows the example of a different switching schedule. It is a figure which shows the example which changes the switching schedule in a plurality of cycles. It is a schematic diagram which shows the change angle of a tilt mirror. It is a figure which shows the application example of a general drive voltage. It is a figure which shows the application example of the drive voltage in this embodiment. It is a figure which shows the application example of this invention. It is a figure which shows the optical element which branches the incident light from a light source into a plurality of lines.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a light propagation device 100 according to the present embodiment. The light propagation device 100 is a device that branches and emits incident light into a plurality of pieces, and uses a MEMS optical switch 120 as an optical branching 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 an incident port for light, and inputs light from the light source 210 via an optical fiber 220 or the like. As the light source 210, for example, a visible light laser light source can be used. However, it may be an LED light source, a lamp, or the like. 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 arranged at a position where the light input from the input port 110 is guided to the reflecting surface thereof. The drive electrode 122 adjusts the tilt angle of the tilt mirror 121 according to the input drive voltage. This makes it possible to change the direction of the reflected light. In this embodiment, one axis will be described as an example, but two axes may be used.

The plurality of output ports 130 and the off port 132 are arranged at positions where the light input to the input port 110 is irradiated by the 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 optical propagation device 100, and by changing the tilt angle of the tilt mirror 121. , Any port of the output side port 134 can be irradiated with the light input to the input port 110. The output side port 134, which is the irradiation destination, is optically coupled to the input port 110.

The output port 130 is an exit port for light, and when the light input to the input port 110 is irradiated, the light is output to the outside via an optical fiber 230 or the like. On the other hand, the off port 132 does not output the light to the outside even if the light input to the input port 110 is irradiated. The off port 132 may be arranged between adjacent output ports 130, or may be provided in plurality. The offport 132 may simply consist of a wall that 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 receiving unit 141 can be configured by a switch, an operation key, or the like, and receives from the user 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.

The light amount control unit 142 can be configured by an arithmetic unit, a memory, or the like, and sets a switching schedule of the irradiation destination of the tilt mirror 121 of the MEMS optical switch 120 according to the setting regarding the light amount received by the setting reception unit 141. The light amount control unit 142 sets a longer period to be allocated to the off port 130 as the set attenuation amount is larger, and sets a larger ratio of the allocation period as the set output port has a larger 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 apparatus 100 in this embodiment will be described. Here, it is assumed that the output port 130 is provided with 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, the period for irradiating the output port 1 with the reflected light of the tilt mirror 121 is W1, the period for irradiating the output port 2 is W2, the period for irradiating the output port 3 is W3, and the output port 4 is irradiated. The period is set to W4, and W1, W2, W3, and W4 are set to be continuous for the same period length as one cycle, and are set to repeat a plurality of cycles. Irradiation to the offport 132 is not performed.

It should be noted that each cycle is a time during which the human eye does not feel flicker when the time is set as the blinking cycle. Specifically, it is preferably shorter than about 33 msec (30 Hz), and can be, for example, about 16 msec (62.5 Hz).

In this case, since each output port repeats blinking at a cycle in which no flicker is felt, the human eye feels that the lighting state is continuous. Specifically, since the lighting period length of each output port is the same, assuming that the amount of light input to the input port 110 is 100%, each output port simultaneously outputs 25% of the light amount. Is recognized as. The loss shall not be taken into consideration.

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

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

That is, by adjusting the period WO for irradiating the off port 132 in one cycle and evenly allocating the remaining period to each output port, the light intensity of each output port can be uniformly changed.

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

For example, if a switch for "attenuation amount 0", "medium attenuation amount", and "large attenuation amount" is prepared in the setting reception unit 141, and "attenuation amount 0" is selected by the light amount control unit 142, 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 "Large attenuation" is selected. , It is possible to perform an operation such as setting a switching schedule as shown in FIG. 3 (b). In this case, since the light amount control unit 142 does not need to perform complicated control, it can be realized by a logic circuit, for example, and can be easily configured. Of course, the WO period can be arbitrarily set, and the attenuation amount can be flexibly set.

The time period assigned to each output port does not have to 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% of the light amount is output from the output port 1 and 25% of the 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 amount ratio of each output port can be arbitrarily changed, it can be referred to as a light amount 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 specifying the attenuation amount are prepared in the setting reception unit 141, and the light amount control unit 142 assigns them to the off port based on the designation of the attenuation amount. It is possible to set the WO period, and for the remaining period, set a switching schedule in which the period is assigned to each output port based on the specification of the light intensity ratio. If only one output port is set to allocate the period, only that output port can be illuminated and the amount of light can be changed arbitrarily.

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

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

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

Since the angle of the tilt mirror 121 corresponds to 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 set to V0, and the angle when the change is made by θ. Let V1 be the drive voltage Va (t) corresponding to.

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

Therefore, in the present 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 the tilt mirror 121 is changed 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, which is the first signal corresponding to the first tilt angle. When switching to the drive voltage V1 which is the second signal, the intermediate voltage V2 which is larger than the first signal and smaller than the second signal is output for the intermediate voltage application time (time t2). The fact that the intermediate voltage V2 is 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 above the first signal and less than the second signal, and is not necessarily the first signal. It is not limited to the voltage value between the second signal and the second signal.

Here, it is assumed that V2 and t2 have a relationship in which the maximum amplitude of the angle θ is obtained after the 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 of the maximum amplitude is reached. As a result, vibration of the tilt mirror 121 can be prevented, and the tilt mirror 121 can be quickly stabilized at an angle θ. It should be noted that V2 and t2 on the mounting shall be determined theoretically, experimentally, and the like.

Although the light propagation device 100 of the present embodiment has been described above, the present invention can be applied to various devices. For example, as shown in FIG. 9A, by forming a light emitting window 162 corresponding to the output port 130 on the light emitting side of the output port 130, it can be used as a display device 160. As shown in FIG. 9B, the light emitting window 162 may be arranged in both the horizontal direction and the vertical direction. By doing so, it functions as a display device 160 capable of displaying characters and symbols.

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

100 Optical propagation device 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 unit 141 Setting reception unit 142 Light amount control unit 143 Drive control unit 160 Display device 162 Light source 162 Light Diffuse fiber 170 Lighting device 210 Light source 220 Optical fiber 230 Optical fiber 310 Light source

Claims (6)

An input port that receives light and
An output port that includes multiple output ports that emit light to the outside,
A MEMS optical transistor having a tilt mirror controlled to a tilt angle corresponding to a drive voltage and optically coupling any of the input port and the output side port according to the tilt angle of the tilt mirror.
A setting reception unit that accepts settings related to the amount of light to be output,
A light amount control unit that sets a switching schedule indicating the allocation period of each port of the output side port for each cycle based on the setting regarding the light amount.
A drive control unit that outputs the drive voltage based on the switching schedule is provided.
The output side port includes an off port that does not output light to the outside.
The setting receiving unit receives the setting regarding the amount of light attenuation, and receives the setting.
The light amount control unit is a light propagation device characterized in that the larger the set attenuation amount is, the longer the period allocated to the off-port is set . The setting receiving unit receives the setting regarding the amount of light for each output port, and receives the setting.
The light propagation device according to claim 1, wherein the light amount control unit sets a larger ratio of the allocation period as the set output port has a larger light amount. The drive control unit
When the tilt mirror is changed from the first tilt angle to the second tilt angle, the first signal is used when switching from the first signal corresponding to the first tilt angle to the second signal corresponding to the second tilt angle. The light propagation apparatus according to claim 1 or 2, wherein an intermediate voltage larger than or smaller than the second signal is output for an intermediate voltage application time. The intermediate voltage is a drive voltage that becomes the second tilt angle at the time of the maximum amplitude of the tilt mirror at the time of transient response.
The light propagation apparatus according to claim 3, wherein the intermediate voltage application time is a time until the tilt mirror reaches the maximum amplitude. The light propagation apparatus according to any one of claims 1 to 4,
A light emitting window corresponding to the output port and
A display device characterized by being equipped with. The light propagation apparatus according to any one of claims 1 to 4,
With the optical diffusion fiber connected to the output port,
A lighting device characterized by being equipped with.

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