CN111474704B

CN111474704B - Light modulator

Info

Publication number: CN111474704B
Application number: CN202010180223.6A
Authority: CN
Inventors: 李长城
Original assignee: Harbin Xinguang Photoelectric Technology Co ltd
Current assignee: Harbin Xinguang Photoelectric Technology Co ltd
Priority date: 2020-03-16
Filing date: 2020-03-16
Publication date: 2021-10-19
Anticipated expiration: 2040-03-16
Also published as: CN111474704A

Abstract

In order to solve the defects that a mechanical shutter cannot ensure the long-term stable operation of equipment, a liquid crystal light valve has low transmittance and low contrast and does not meet the technical requirements of a moving target simulator, the invention provides a light modulator, which comprises: the control mechanism is used for controlling the rotation of the dimming disc; the first region is used for enabling the first light path to work through the reflection effect of the surface of the first region when the light source light path is cut; and when the light source light path is switched, the light source light path misses the dimming disc and the second light path works. The invention can meet the frame frequency requirement of 200Hz at most; compared with a mechanical shutter, the liquid crystal shutter can guarantee long-time stable work, has long service life, and has high reflectivity, high transmissivity and higher light efficiency utilization rate compared with a liquid crystal light valve with lower transmissivity. The invention is suitable for the improvement of the moving target simulator.

Description

Light modulator

Technical Field

The invention relates to the field of dynamic target simulator components, in particular to a dimmer.

Background

The visible light moving target simulator is a visible light imaging guidance seeker performance test device and is also an important component of a visible light imaging guidance semi-physical simulation test system. The early moving target simulator is generally only 50Hz or 60Hz frame frequency or higher and reaches 100Hz frame frequency, the frame frequency of the simulator needs to be correspondingly improved along with the continuous increase of the frame frequency of the optical sensor of the seeker, the simulator needs to realize 200Hz frame frequency, the simulator cannot use large-size imaging devices due to the limitation of the volume, the highest frame frequency of the available imaging devices is only 100Hz, therefore, 2 imaging devices are adopted in the design scheme of the simulator to alternately work to realize the 200Hz imaging frame frequency requirement, a dimming device needs to be designed, the quick switching of 2 optical paths is realized, the switching frequency is not lower than 200Hz, and the simulator needs to stably operate for a long time.

The existing mode for realizing the rapid switching of the optical path mainly comprises shutter switching or a liquid crystal light valve, wherein an electronic shutter and a mechanical shutter are switched in the shutter switching mode, the electronic shutter and the mechanical shutter are generally used for camera imaging, the electronic shutter utilizes the principle that a camera photosensitive device is not electrified and does not work, the photosensitive device is electrified for a period of time when a camera shutter button is pressed, the shutter effect is formed, the on-off of a light beam is not really controlled, and therefore the electronic shutter is not suitable for the system, the mechanical shutter controls the opening and closing of blades by utilizing a mechanical spring or an electromagnetic means to control the opening and closing of the light beam, the requirement of the system is the same as that of the mechanical shutter, but the mechanical shutter has the service life limitation, the simulator can be opened and closed 72 thousands of times when working for one hour at the switching frequency of 200Hz, and the long-term stable operation of the device cannot be ensured. The liquid crystal light valve controls the on-off of light by controlling the torsion of liquid crystal molecules, has high speed, but has low transmittance and low contrast ratio, and does not meet the technical requirements of a moving target simulator.

Disclosure of Invention

The invention aims to overcome the defects that the mechanical shutter cannot ensure the long-term stable operation of equipment when working at the switching frequency of 200Hz, and the liquid crystal light valve has low transmittance and low contrast and does not meet the technical requirements of a moving target simulator.

According to a first aspect of the present invention, there is provided a dimmer comprising: the control mechanism is used for controlling the rotation of the dimming disc; the first region is used for enabling the first light path to work through the reflection effect of the surface of the first region when the light source light path is cut; and when the light source light path is switched, the light source light path misses the dimming disc and the second light path works.

Preferably, the first region comprises two wing-like sub-regions which are position-symmetrical along the rotation axis.

Preferably, the control mechanism includes a main control unit, a driving motor and a photoelectric switch, the photoelectric switch is capable of outputting a level pulse signal when the dimming disc completes one cycle of rotation, and the main control unit is configured to determine a motor shaft rotation frequency of the driving motor and a phase of the driving motor relative to the photoelectric switch through the level pulse signal.

Preferably, the main control unit is further configured to receive an external synchronization signal, so that the rotation frequency and the phase of the dimming disc are synchronized with the frequency and the phase of the external synchronization signal.

Preferably, when the input frame frequency value is lower than the preset value, the control mechanism controls the rotation of the dimming disc to a position where the first optical path or the second optical path can work, and then stops the rotation of the dimming disc.

Preferably, the control mechanism further comprises an encoder card, an analog quantity card and a digital quantity card; the digital volume card is used for receiving the pulse level of the external synchronizing signal and the photoelectric switch feedback signal; the analog quantity card is used for outputting an analog quantity voltage signal, and the motor driver can regulate the speed within a preset range after receiving the analog quantity voltage signal; the encoder card is used for judging the position of the current dimming disc according to the feedback signal of the encoder.

Preferably, the dimmer is for a seeker moving target simulator.

The invention has the beneficial effects that:

1. when the highest frame frequency of a single imaging device cannot meet the requirement, the invention can enable 2 imaging devices to alternately work to meet the requirement;

2. the device can receive an external synchronous signal, so that the rotation frequency and the phase of the dimming disc are consistent with those of the external signal; the phase drift phenomenon can not be generated;

3. the method provides a solution for the high frame frequency display of the visible light moving target simulator; in one embodiment, the frame frequency requirement of up to 200Hz can be met.

4. Compared with a mechanical shutter, the mechanical shutter can guarantee long-time stable work and has long service life.

5. Can work under a single optical path and can meet the requirements of a low frame frequency simulator.

6. Compared with the liquid crystal light valve with lower transmittance in the prior art, the liquid crystal light valve has high reflectivity, high transmittance and higher light efficiency utilization rate.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

FIG. 1(a) is a schematic diagram of a dimmer according to an embodiment of the present invention; FIG. 1(b) is a block diagram of one embodiment of a dimmer; FIG. 1(c) is a schematic diagram of a master control unit;

fig. 2(a) is a schematic structural diagram of a dimming disc and a first area according to an embodiment of the invention;

FIG. 2(b) is a schematic diagram of a first area-cut light source circuit according to an embodiment of the present invention; FIG. 2(c) is a schematic diagram of a first area-cut light source circuit according to an embodiment of the present invention;

FIG. 3(a) is a block diagram of another embodiment of a dimmer; FIG. 3(b) is a view of the structure of FIG. 3(a) viewed from another angle;

fig. 4 is a control schematic diagram of an embodiment when the master control unit is a control computer.

Description of reference numerals:

1-dimming disk 12-baffle

2-motor coupling 3-motor support

4-drive motor 5-photoelectric switch

6-control System 7-light Source System

71-light Source optical path 81-Transmission optical path

82-reflection optical path 9-beam combining mirror

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

The invention aims to provide equipment capable of adapting the frame frequency of a moving target simulator to a high-frame-frequency optical sensor, and the invention selectively uses a light modulator to achieve the aim of the invention by considering the size and the maximum frame frequency limit of an imaging device, namely, the light modulator capable of enabling two light paths to work alternately meets the requirement of high frame frequency.

The invention provides a dimmer, a dimming disc and a control mechanism, wherein the control mechanism is used for controlling the rotation of the dimming disc; the dimming disc is provided with a first area, and the first area is used for enabling the first light path to work through the reflection action of the surface of the first area when the light source light path is cut; and when the light source light path is switched, the light source light path is staggered by the optical disk adjusting sheet, and the second light path works.

Schematic diagrams of an embodiment are shown in fig. 1(a) to 1(c), and schematic diagrams of structures of the dimming discs are shown in fig. 2(a) to 2 (c). It can be seen that the dimming disc 1 periodically has two states of a cut-in light path and a cut-out light path when rotating, and because the dimming disc 1 has a certain reflectivity, a light source is reflected by the dimming disc 1 when cutting in the light path, so that the reflection light path 82 works, and the transmission light path 81 does not work; when the light path is cut out, the light source light path 71 and the dimming disc 1 miss each other, the transmission light path 81 is operated, and the reflection light path 82 is not operated. The reflection light path 82 and the transmission light path 81 are combined by the beam combining mirror 9, so that high frame rate imaging can be realized under the condition that the two light paths work alternately. The reflection light path 82 and the transmission light path 81 are names provided for convenience of distinction, and the reflection light path 82 is used for reflection by the dimming disc 1, and the transmission light path 81 is used for non-reflection, and the two light paths contain optical elements without difference. In fig. 1(c), the control system is electrically connected to other components of the dimmer, so that the mechanical connection is not shown; the control system may be a control computer having an embodiment of a specific control connection with the dimmer as shown in fig. 4.

It can be seen from the embodiment shown in fig. 2 that the first region 11 of the dimming disc comprises two wing-like subregions which are symmetrical to one another along the center of rotation. Fig. 2(b) is a schematic diagram of the first region when the light source light path 71 is cut, in which a dashed circle represents a light passing area formed by the light source light path, and when any one of wing-shaped sub-regions 11 is cut into the light source light path 71, the reflected light path 82 works; fig. 2(c) is a schematic diagram of the first area cut light source optical path 71, and the transmission optical path 81 operates when the light source optical path 71 is cut. Since the light modulation disk 1 switches the light source light path twice and switches the light source light path twice when the light modulation disk 1 rotates once, the 200Hz imaging frame frequency can be realized when the rotation frequency of the light modulation disk 1 is set to 50 Hz. It should be noted that "symmetrical to each other" means generally symmetrical in position, and it is not necessary that the shape is completely symmetrical, because the portion of the region corresponding to the light-passing area is mainly used in practical use regardless of the shape of the wing-shaped sub-region.

As can be seen from the embodiment provided in fig. 2, the function of the optical path switching function of the dimming disc mainly results from the fact that a part of the area exists on the disc, the disc can cut into the light path of the light source when rotating to a certain angle range, and the light path is reflected into the reflected light path by using the high surface reflectivity of the area, and when the light path is cut out in the area, the light path and the dimming disc miss each other and enter the transmission light path (without changing the light source system). Therefore, those skilled in the art will appreciate that the dimming disc can be configured in other shapes, for example, the first region can include more wing-shaped subregions, and the shape of the wing-shaped subregions can be selected from various shapes as long as the size of the wing-shaped subregions can be matched with the light-transmitting area.

Fig. 3 shows an embodiment of a control mechanism, which includes a main control unit 6, a driving motor 4, and an electro-optical switch 5, wherein the electro-optical switch 5 can output a level pulse signal when the dimming disc 1 completes one cycle of rotation, and the main control unit 6 is configured to determine a motor shaft rotation frequency of the driving motor 4 and a phase of the driving motor relative to the electro-optical switch according to the level pulse signal. In the embodiment shown in fig. 1(b), a shutter 12 may be provided on the dimmer disc to enable the opto-electronic switch to identify whether the dimmer disc has completed one cycle of rotation, i.e., when the dimmer disc is rotated to a particular position, the shutter just blocks the opto-electronic switch, i.e., identifies that one cycle of rotation has been completed.

The photoelectric switch can output a level pulse signal when the dimming disc is shielded, and the main control unit is used for determining the rotation frequency of a motor shaft of the driving motor and the phase of the driving motor relative to the photoelectric switch through the level pulse signal.

The main control unit is also used for receiving the external synchronizing signal and synchronizing the rotation frequency and the phase of the dimming disc with the frequency and the phase of the external synchronizing signal. This is to adjust the frame rate under the action of the external synchronization signal, thereby avoiding the phase drift phenomenon.

In one embodiment, the main control unit may detect a frame frequency value required to be achieved, and when the input frame frequency value is lower than a preset value, the control mechanism controls the rotation of the dimming disc to a position where the first optical path or the second optical path can be operated, and then the rotation of the dimming disc is stopped. For example, when the frame frequency of the imaging device is 50Hz and the frame frequency value to be achieved is less than 50Hz, the dimmer may be rotated to a position where one of the first optical path or the second optical path is operated, and the dimmer does not need to be rotated. This allows the dimmer to have an extended operating life at low frame rate operating requirements.

The control mechanism may further include an encoder card, an analog quantity card, and a digital quantity card for collecting signals, as shown in fig. 4, the control computer is used to complete the functions of the main control unit, and the digital quantity card is used to receive the pulse levels of the external synchronization signal and the feedback signal of the photoelectric switch; the analog quantity card is used for outputting an analog quantity voltage signal, and the motor driver can regulate the speed within a preset range after receiving the analog quantity voltage signal; the encoder card is used for judging the position of the current dimming disc according to the feedback signal of the encoder.

The dimmer of the invention is especially suitable for improving the seeker moving target simulator, because the size is smaller, does not need to occupy a large space in the working process, thus being beneficial to the miniaturization of the seeker, and when the seeker or the simulator has volume limitation, the dimmer can meet the requirements of miniaturization and high frame frequency.

< example 1>

The dimmer structure of the present embodiment is shown in fig. 1, and comprises a dimming disc 1, a motor coupler 2, a servo motor 3, a photoelectric switch 4, a motor bracket 5 and a control system 6. The optical disc 1 has the structure shown in fig. 2(a), the size of the optical disc is designed according to the light transmission area, the optical disc is precisely machined by a diamond lathe, the surface shape precision and the reflectivity are high, the reflection optical path 82 works when the optical disc 1 is cut into the optical path, and the transmission optical path 81 works when the optical disc 1 is cut out of the optical path. The dimming disc 1 is connected with the servo motor 3 through the motor coupler 2, the reflection light path 82 and the transmission light path 81 can work for 2 times respectively by one rotation of the motor, so that the rotation frequency of the dimming disc 1 is set to be 50Hz, namely, 200Hz frame frequency can be realized, the servo motor 3 is adopted to drive the rotation frequency of 50Hz to correspond to the rotation speed of 3000 rpm, and the rotation speed is within the range of the rated rotation speed of the servo motor 3 and can work for a long time. The photoelectric switch 4 adopts a U-shaped groove structure, a blocking piece 12 is arranged on the light adjusting disk, the photoelectric switch can be blocked and triggered once every 1-cycle rotation, a level pulse signal is output, and the rotation frequency of a motor shaft and the phase relative to the photoelectric switch can be detected through the photoelectric switch 4. The control system 6 receives the external synchronizing signal and drives the motor to rotate under the control of the external synchronizing signal. In the embodiment, the rotation frequency and the phase of the dimming disc are synchronous with the frequency and the phase of the external synchronous signal by designing a reasonable dimming mode and driving and controlling the dimming disc.

The embodiment can enable the moving target simulator to meet the frame frequency requirement of 200Hz at most; the frame frequency is adjusted under the action of the external synchronization signal, the synchronization precision is high, and the phase drift phenomenon cannot be generated; the device can automatically adapt to external synchronous signals and is compatible with the requirements of a low frame frequency simulator; the motor is adopted to rotate and drive the dimming, so that the LED lamp can stably run for a long time.

< example 2>

This embodiment further includes, on the basis of the hardware of embodiment 1, installing a digital I/O card, an analog DA card, and an encoder card on the PCI bus of the control computer, for implementing sampling and outputting of the control signal: the digital I/O card receives the pulse level of an external synchronizing signal and a photoelectric switch feedback signal, the analog DA card can output an analog voltage signal of-10V to +10V, the motor driver receives the analog voltage signal to drive the motor to regulate the speed in the range of-3500 r/min to +3500 r/min, and a certain speed regulation margin is reserved to avoid the problem of poor synchronization caused by the frequency jitter of an input signal; servo motor itself is furnished with the encoder, and encoder card detects encoder feedback and can obtains current dimming piece positional information, and an image device can satisfy the requirement when the low frame frequency, consequently can control the fixed work of dimming dish at certain side light path, prolongs the life of dimmer.

The control computer of the embodiment is used as a core of control, corresponding synchronous drive control software is designed, the frequency and the phase are calculated through the rising edge time of the collected external synchronizing signal and the photoelectric switch output signal, the PID control algorithm is adopted to realize the adjustment of the frequency and the phase, the frequency and the phase of the photoelectric switch output signal and the external synchronizing signal are synchronous, and the phase deviation caused by the installation deviation of the photoelectric switch can be eliminated by setting a phase deviation parameter in the software, so that the working time of a reflection light path and a transmission light path is accurately controlled. The embodiment is applied to a moving target simulator to meet the requirement of technical index frame frequency of 200 Hz.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A dimmer, comprising:

the control mechanism is used for controlling the rotation of the dimming disc;

the first region is used for enabling the first light path to work through the reflection effect of the surface of the first region when the light source light path is cut; and when the light source light path is switched, the light source light path misses the dimming disc and the second light path works

The control mechanism comprises a main control unit, a driving motor and a photoelectric switch, the photoelectric switch can output a level pulse signal when the dimming disc completes one period of rotation, and the main control unit is used for determining the rotation frequency of a motor shaft of the driving motor and the phase of the driving motor relative to the photoelectric switch through the level pulse signal;

the main control unit is also used for receiving an external synchronizing signal to synchronize the rotation frequency and the phase of the dimming disc with the frequency and the phase of the external synchronizing signal;

the dimmer is used for a seeker moving target simulator;

the dimmer is used to alternate the 2 imaging devices to achieve the imaging frame rate requirement.

2. A dimmer according to claim 1, wherein the first region comprises two wing-like subregions symmetrical to each other along the center of rotation.

3. The dimmer of claim 1, wherein the control mechanism stops the rotation of the dimmer disc after controlling the rotation of the dimmer disc to a position enabling the first optical path or the second optical path when the input frame rate is lower than the predetermined value.

4. The dimmer of claim 1, wherein said control mechanism further comprises an encoder card, an analog quantity card, a digital quantity card; the digital volume card is used for receiving the pulse level of the external synchronizing signal and the photoelectric switch feedback signal; the analog quantity card is used for outputting an analog quantity voltage signal, and the motor driver can regulate the speed within a preset range after receiving the analog quantity voltage signal; the encoder card is used for judging the position of the current dimming disc according to the feedback signal of the encoder.