KR20090021607A - Rotator position measuring system - Google Patents

Abstract

A rotator position measuring system is provided to reduce the power consumption by using the light emitting diode and the photo diode in stead of the laser diode. A sensing part(210) is connected to one part of the rotor in which the scanning mirror and the axis of rotation are connected. The sensing part comprises a shadowing plate(216) which rotates corresponding to the rotation of the scanning mirror; an LED(212) irradiating the light in the specified direction; and a photo diode(214) which receives the light irradiated from the LED. The light irradiated from the LED is received to the photo diode. A sensing signal transform unit(220) converts the quantity of light light-received to the photo diode into the sensing signal. A controller(230) receives the sensing signal transformed from the sensing signal transform unit. The controller delivers the scanner control signal to a scanner control part(240).

Description

Rotorator position measuring system

The present invention relates to a scanner, and more particularly, to a system for measuring the position of a rotor of a scanner using a change in light quantity.

Scanners such as galvanometers are widely used as a means for controlling the path of light rays not only in display devices but also in the equipment industry using lasers.

1 is a schematic configuration diagram of a scanning display apparatus using a scanner.

An image signal in the form of a line beam is emitted from the light source 110. The light source 110 includes a one-dimensional optical modulator in a projection manner, and generates and outputs modulated light carrying desired image information by adjusting the micro mirror displacement of the one-dimensional optical modulator according to a control signal from the image controller. Modulated light has a linear light form.

In order to express the modulated light having the linear light form on the screen 130 as a 2D image, a scanner 120 is required. The scanner 120 changes the path to reflect the modulated light emitted from the light source 110 according to the control signal from the image controller to reach a predetermined position on the screen 130. By rotating within a predetermined range for a predetermined time, the scanner 120 allows the modulated light in the form of linear light on the screen 130 to be scanned over time to implement a two-dimensional image. Here, the scanner 120 may be a galvanometer equipped with a mirror on the rotating shaft. The scanner 120 includes a motor (not shown) capable of rotating in both directions, and reflects the modulated light toward the screen 130 while rotating by the motor.

Performance specifications required for applying such a scanner to a display device include linearity, repeatability, validity period, etc., and accurate positioning of the rotor of the scanner is essential to satisfy such performance specifications.

Galvanometers are a type of motor that can only move within a certain angle range. Therefore, in the galvanometer, there is a problem in that it is difficult to use a tacho meter or an encoder widely used in a conventional motor due to the influence of load inertia, etc., in order to obtain position information.

Accordingly, the present invention is to provide a rotor position measuring system capable of accurately determining the rotor of the scanner by using the change in the amount of light.

In addition, the present invention uses a light emitting diode (LED) and a photo diode (PD) to reduce the power consumption compared to using a laser diode (LD) laser and occupies only a small space To provide a position measuring system.

Other objects of the present invention will be readily understood through the following description.

According to an aspect of the invention, the sensing unit for detecting the amount of light that changes according to the position of the rotor of the scanner; A sensing signal converting unit converting the amount of light into a sensing signal; And a controller for determining a position of the rotor from the sensing signal.

Here, a scanner control unit for controlling the scanner according to the scanner control signal, the control unit may generate a scanner control signal for controlling the rotation of the scanner in accordance with the position of the rotor determined from the sensing signal.

And the sensing unit, LED for irradiating light in a predetermined direction; A photodiode for receiving light irradiated from the LED; And a blocking plate positioned between the LED and the photodiode and connected to the rotor to rotate in response to the rotation of the rotor to adjust the amount of light transmitted from the LED to the photodiode.

In addition, two photodiodes may be continuously arranged.

Here, the two photodiodes may have opposite directions of change in the amount of light received by rotation of the shielding plate. The shielding plate is divided into a V-shaped shielding region and an opening region between the shielding regions, and the opening region is positioned at a position to open all or part of each of the two photodiodes according to the rotation of the rotor. Can be arranged. In addition, the shielding plate may have a shielding area covering at most one photodiode, and the shielding area may be disposed at a position covering all or part of each of the two photodiodes according to the rotation of the rotor. The sensing signal converter may generate the sensing signal by differentiating the amount of light received by the two photodiodes.

Here, the scanner may be a galvanometer.

The rotor position measuring system according to the present invention can accurately determine the position of the rotor of the scanner by using the change in the amount of light.

In addition, the use of light emitting diodes and photodiodes reduces the power consumption and occupies only a small space compared to using laser diodes.

In addition, when using a conventional laser diode and a position sensitive detector (PSD), a relatively large area position sensitive detector is required in order to increase the resolution of a sensing signal. By adjusting the area of the part, the resolution of the sensing signal can be increased even in a relatively small area.

In addition, by using two photodiodes, the signal from each photodiode can be differentiated to further increase the accuracy and accuracy of the sensing signal.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, the scanner is applied to a display apparatus for displaying a two-dimensional image implemented by scanning the linearly modulated light generated by the one-dimensional optical modulator in a constant direction at a constant speed. The one-dimensional optical modulator generates linearly modulated light carrying an image signal corresponding to any one of the scanning lines forming a two-dimensional image on a linear beam of a line beam type incident from a laser light source. The driving method is an electrostatic method or a piezoelectric method. And so on.

2 is a schematic configuration diagram of a rotor position measuring system according to an embodiment of the present invention.

The rotor position measuring system includes a sensing unit 210, a sensing signal converter 220, and a controller 230. In addition, the scanner control unit 240 may further include. This rotor position measurement system is connected to the scanner 120 of the display device. Hereinafter, for the convenience of understanding and explanation of the invention, it is assumed that the scanner 120 is a galvanometer, but the same content is applicable to other polygon mirrors, rotation bars, and the like.

The scanner 120 has a scanning mirror connected to the rotating shaft, and the rotating shaft is connected to the structure at the bottom to transmit the rotation of the structure to the scanning mirror to rotate the scanning mirror clockwise or counterclockwise. The structure is connected to the motor, and the rotation direction, rotation speed, etc. of the structure are determined according to the control signal applied from the scanner controller 240. Hereinafter, this structure is called a rotor.

The sensing unit 210 is connected to a part of the rotor (eg, the top or the bottom of the rotor) to which the scanning mirror and the rotating shaft are connected, and the blocking plate 216 rotates in correspondence with the rotation of the rotor, that is, the scanning mirror. And a LED 212 for irradiating light in a predetermined direction and a photodiode 214 for receiving light irradiated from the LED 212. Here, rotating correspondingly is not only the obstruction plate 216 rotating in proportion to or inversely proportional to the rotation of the scanning mirror. It is meant to include the same rotation, and the proportional and inverse relationship is not limited to the linear one.

Photodiode 214 receives light emitted from LED 212. Here, the shield plate 216 is positioned between the photodiode 214 and the LED 212 and rotates in accordance with the rotation of the scanning mirror, and blocks a part of the light irradiated from the LED 212 to the photodiode 214. do. The photodiode 214 receives light emitted from the LED 212 as the obstruction plate 216 rotates. The structure and the sensing operation of the sensing unit 210 will be described in more detail later with reference to FIG. 3A.

The sensing signal converter 220 converts the amount of light received by the photodiode 214 into a sensing signal. The sensing signal is a signal corresponding to the amount of light, and its value changes as the screen plate 216 rotates.

The controller 230 receives the sensing signal converted by the sensing signal converter 220 and determines the position of the current blocking plate 216 according to the size of the sensing signal. The scanner control signal 240 determines the position of the rotor of the current scanner 120 based on the determined position of the current screen 216 and controls the rotation direction, the rotation speed, and the like of the scanner 120. To pass.

The scanner controller 240 generates a control signal for controlling the rotation direction, the rotation speed, etc. of the rotor of the scanner 120 according to the scanner control signal from the controller 230 and applies it to the scanner 120. The control signal may be in the form of voltage or current for rotating the motor provided in the rotor of the scanner 120 in a clockwise or counterclockwise direction.

Hereinafter, the structure and the sensing operation of the sensing unit 210 will be described in more detail with reference to FIG. 3A and the following drawings.

3A and 3B are views illustrating structures of a shielding plate and a photodiode of a sensing unit according to an embodiment of the present invention, and FIG. 4 is a graph showing a change in light quantity of a photodiode. 3A and 3B show that the shielding plate is changed in position depending on the position of the rotor. 3A and 3B are views viewed downward along the line AA ′ of FIG. 2.

The LED 212 is positioned above the shield plate 216, and the photodiode 214 is disposed on the lower side so that the LED 212 can receive the light irradiated. This is only an example, and on the contrary, an LED may be positioned below the blocking plate 216 and a photo diode may be disposed above.

The shielding plate 216 is divided into a V-shaped shielding area 302 and an opening area 304 therebetween. And it rotates clockwise or counterclockwise about the rotating shaft 300. The shield plate 216 is connected to the scanner 120 to rotate by a predetermined angle corresponding to the rotation of the rotor.

Since the blind area 302 blocks the progress of light emitted from the LED 212, the photodiode 214 does not receive light that is blocked by the blind area 302. Since the open area 304 propagates the light emitted from the LED 212 as it is, the photodiode 214 receives the light passing through the open area 304.

Accordingly, the photodiode 214 does not receive light obscured by the obstruction region 302 among the light emitted from the LED 212, and receives the light passed by the open region 304.

Here, the photodiode 214 includes a first photodiode 214a and a second photodiode 214b. The first photodiode 214a and the second photodiode 214b are disposed continuously.

As shown in FIG. 3A, the center line 320 of the blind plate 216 coincides with the center line 310 of the first photodiode 214a, and B is shown in FIG. 3B. C is a case where the center line 320 of the c) forms an angle with the center line 310 of the first photodiode 214a by α.

In the case of B, the first photodiode 214a receives the most light from the LED 212 by the open area 304 of the obstruction plate 216, and the second photodiode 214b receives the obstruction plate 216. Occlusion area 302 receives the least light from the LED 212 (see curve 410 in FIG. 4).

In case of C, the first photodiode 214a receives the least light from the LED 212 by the shielding region 302 of the shielding plate 216, and the second photodiode 214b blocks the shielding plate 216. Open area 304 causes the most light to be received from LED 212 (see curve 420 in FIG. 4).

In the case of the galvanometer used in the display device of the scanner 120, the clockwise or counterclockwise rotation is repeated within a predetermined angle. Thus, assuming that both sides of the boundary within the predetermined angle are the case B and the case C, respectively, the obstruction plate 216 is also shown in FIG. 3A and FIG. 3B by rotation within the predetermined angle of the scanner 120. It will rotate between the positions in the case shown.

The amount of light of the first photodiode 214a decreases linearly by the rotation from the case B to the case C (clockwise rotation). The light amount of the second photodiode 214b increases linearly.

The light amount of the first photodiode 214a increases linearly by the rotation from the C case to the B case (counterclockwise rotation). The light amount of the second photodiode 214b decreases linearly.

That is, the amount of light received by the first photodiode 214a and the second photodiode 214b is linearly changed by the rotation of the obstruction plate 216 corresponding to the rotation of the scanner 120.

When the blocking plate 216 is rotated as far as possible in the counterclockwise direction, the first photodiode 214a receives the maximum light amount, and the second photodiode 214b receives the minimum light amount. In addition, when the blocking plate 216 is rotated as far as possible in the clockwise direction, the first photodiode 214a receives the minimum light amount, and the second photodiode 214b receives the maximum light amount.

As such, the amount of light received by the first photodiode 214a and the second photodiode 214b exhibits a linear change characteristic opposite to the rotation of the obstruction plate 216.

Therefore, the sensing signal converter 220 may increase the sensing resolution by differentiating the amount of light received by the first photodiode 214a and the second photodiode 214b.

By discriminating the amount of light received by the first photodiode 214a and the second photodiode 214b, it is possible to determine the position of the obstruction plate 216 more accurately, and the scanner 120 from the position of the obstruction plate 216. The rotor position can be determined.

The control unit 230 changes the amount of light of the first photodiode 214a and the amount of light change of the second photodiode 214b according to the position of the obstruction plate 216 according to the rotor position, the position of the obstruction plate 216. Is stored in advance. The light quantity change value measures the change in the amount of light received through the first photodiode 214a while the first scanner 120 is rotated, and the change in the amount of light received through the second photodiode 214b, and measures the storage means ( For example, by storing in a memory, etc.).

5A and 5B are views illustrating structures of the shielding plate and the photodiode of the sensing unit according to another exemplary embodiment of the present invention. 5a and 5b show that the shielding plate is changed in position depending on the position of the rotor. 5A and 5B are views viewed downward along the line AA ′ of FIG. 2.

The LED 212 is positioned above the shield plate 216, and the photodiode 214 is disposed on the lower side so that the LED 212 may receive light to be irradiated. This is only an example, and on the contrary, an LED may be positioned below the blocking plate 216 and a photo diode may be disposed above.

Since the blind area 502 blocks the progress of light emitted from the LED 212, the photodiode 214 does not receive light that is blocked by the blind area 502.

Here, the photodiode 214 includes a first photodiode 214a and a second photodiode 214b. The first photodiode 214a and the second photodiode 214b are disposed continuously.

As shown in FIG. 5A, a case where the center line 520 of the blind plate 216 coincides with the center line 510 of the first photodiode 214a is referred to as D, and the blind plate 216 as shown in FIG. 5B. E is a case where the center line 520 of FIG. 1 forms an angle equal to β with the center line 310 of the first photodiode 514a.

In the case of D, since the first photodiode 214a has the largest portion of the obstruction region 502 of the obstruction plate 216, the first photodiode 214a receives the light from the LED 212 least, and the second photodiode 214b has the smallest portion of the obstruction plate 216 covered by the obstruction region 502, so that the light from the LED 212 is received the least (see curve 410 in FIG. 4).

In the case of E, since the portion of the first photodiode 214a that is covered by the obstruction region 502 of the obstruction plate 216 is least, it receives the most light from the LED 212 and the second photodiode ( 214b has the largest portion of the obstruction region 502 of the obstruction plate 216, so that it receives the least light from the LED 212 (see curve 420 in FIG. 4).

In the case of the galvanometer used in the display device of the scanner 120, the clockwise or counterclockwise rotation is repeated within a predetermined angle. Thus, assuming that both sides of the boundary within the predetermined angle are the case D and E, respectively, the obstruction plate 216 is also shown in FIG. 5A and FIG. 5B by rotation within the predetermined angle of the scanner 120. It will rotate between the positions in the case shown.

The amount of light of the first photodiode 214a decreases linearly by the rotation from the case D to the case E (clockwise rotation). The light amount of the second photodiode 214b increases linearly.

The light amount of the first photodiode 214a increases linearly by the rotation from the E case to the D case (counterclockwise rotation). The light amount of the second photodiode 214b decreases linearly.

That is, the amount of light received by the first photodiode 214a and the second photodiode 214b is linearly changed by the rotation of the obstruction plate 216 corresponding to the rotation of the scanner 120.

When the blocking plate 216 is rotated as far as possible in the counterclockwise direction, the first photodiode 214a receives the maximum light amount, and the second photodiode 214b receives the minimum light amount. In addition, when the blocking plate 216 rotates in the clockwise direction, the first photodiode 214a receives the minimum light amount, and the second photodiode 214b receives the maximum light amount.

As such, the amount of light received by the first photodiode 214a and the second photodiode 214b exhibits a linear change characteristic opposite to the rotation of the obstruction plate 216.

Therefore, the sensing signal converter 220 may increase the sensing resolution by differentiating the amount of light received by the first photodiode 214a and the second photodiode 214b.

By discriminating the amount of light received by the first photodiode 214a and the second photodiode 214b, it is possible to determine the position of the obstruction plate 216 more accurately, and the scanner 120 from the position of the obstruction plate 216. The rotor position can be determined.

The control unit 230 changes the amount of light of the first photodiode 214a and the amount of light change of the second photodiode 214b according to the position of the obstruction plate 216 according to the rotor position, the position of the obstruction plate 216. Is stored in advance. The light quantity change value measures the change in the amount of light received through the first photodiode 214a while the first scanner 120 is rotated, and the change in the amount of light received through the second photodiode 214b, and measures the storage means ( For example, by storing in a memory, etc.).

In the present invention, the sensing unit 210 may be a rotor position measuring apparatus including a blind plate 216, an LED 212, and a photodiode 214.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

1 is a schematic configuration diagram of a scanning display apparatus using a scanner.

2 is a schematic configuration diagram of a rotor position measuring system according to an embodiment of the present invention.

3A and 3B illustrate structures of a shielding plate and a photodiode of a sensing unit according to an embodiment of the present invention.

4 is a graph showing a change in light amount of a photodiode.

5A and 5B illustrate structures of a shielding plate and a photodiode of a sensing unit according to another exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

110: light source

120: scanner

130: screen

210: sensing unit

220: sensing signal conversion unit

230: control unit

240: scanner control unit

Claims (9)

Sensing unit for detecting the amount of light that changes according to the position of the rotor of the scanner; A sensing signal converting unit converting the amount of light into a sensing signal; And Rotor position measurement system including a control unit for determining the position of the rotor from the sensing signal. The method of claim 1, Including a scanner control unit for controlling the scanner in accordance with a scanner control signal, And the control unit generates a scanner control signal for controlling the rotation of the scanner according to the position of the rotor determined from the sensing signal. The method of claim 1, The sensing unit, LED for irradiating light in a certain direction; A photodiode for receiving light irradiated from the LED; And Rotor position measurement is located between the LED and the photodiode, and includes a shielding plate connected to the rotor to rotate in response to the rotation of the rotor to adjust the amount of light transmitted from the LED to the photodiode. system. The method of claim 3, 2. The rotor position measuring system of claim 2, wherein two photodiodes are disposed in succession. The method of claim 4, wherein The two photodiodes are the rotor position measuring system, characterized in that the direction of change in the amount of light received according to the rotation of the shielding plate. The method of claim 4, wherein The shielding plate is divided into a V-shaped shielding area and an open area between the shielding areas, And the open area is disposed at a position to open all or part of each of the two photodiodes in accordance with the rotation of the rotor. The method of claim 4, wherein The shielding plate has a shielding area covering at most one photodiode, And the blind area is disposed at a position covering all or part of each of the two photodiodes according to the rotation of the rotor. The method of claim 4, wherein The sensing signal converting unit generates the sensing signal by differentiating the amount of light received by the two photodiodes. The method of claim 1, And the scanner is a galvanometer.

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