KR101613552B1 - laser projection display and method for compensating image distortion of the same - Google Patents

Abstract

The present invention relates to a laser projection display capable of correcting image distortion and a method of correcting distortion of an image, the method comprising the steps of: displaying the image by a light scanner driven by a driving signal; receiving an external request signal for image distortion correction; Determining a distortion type and a correction condition of an image to be corrected by analyzing a received external request signal and adjusting a driving frequency of the driving signal according to a distortion type and a correction condition of the determined image Generating a control signal, adjusting the driving frequency of the driving signal in accordance with the generated control signal, and generating and outputting the adjusted driving signal to the optical scanner.

Drive frequency, keystone, pin-cushion, image distortion

Description

[0001] The present invention relates to a laser projection display and a method for correcting the image distortion,

The present invention relates to a laser projection display, and more particularly, to a laser projection display capable of correcting image distortion and a method for correcting image distortion thereof.

In general, in addition to a rapid transition to a multimedia society, a large display screen and a high image quality are required, and in recent years, the implementation of a natural color in addition to a high resolution has become important.

In order to realize a perfect natural color, it is necessary to use a high-purity light source such as a laser. One of the devices for implementing an image using a laser is a laser projection display using a light scanner.

Such a laser projection display implements an image by scanning the light generated from a laser light source onto a screen using a light scanner.

Here, in the case of the optical scanner, the driving speed must be high to realize a high resolution image.

That is, the driving speed of the light scanner is high, which means that the driving angle of the light scanner must be large.

The optical scanner tends to increase the driving angle when the driving signal is at a specific frequency. The specific frequency of the driving signal that increases the driving angle of the optical scanner is called the resonance frequency.

Therefore, when the driving signal of the optical scanner corresponds to the resonance frequency, the driving angle becomes the largest, and high-speed driving becomes possible.

However, since the laser projection display uses a light scanner to scan the light generated from the laser light source to the screen, various image distortions may occur due to the distance from the screen or the angle.

Therefore, the problem of correcting image distortion is one of the first problems to be solved in a display device using a light scanner.

An object of the present invention is to provide a laser projection display capable of correcting distortion of a displayed image by finely adjusting a driving frequency of a light scanner to control an angle of a light scanner and an image distortion correction method thereof.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise forms disclosed. .

A laser projection display according to the present invention includes a light scanner driven by a driving signal, an external request signal for image distortion correction, and a control unit for receiving and analyzing an external request signal for controlling distortion of the image, And a drive signal generator for adjusting the drive frequency of the drive signal according to the generated control signal and generating the adjusted drive signal and outputting the adjusted drive signal to the optical scanner.

Here, the driving frequency control unit includes a receiving unit for receiving an external request signal for image distortion correction, a signal analyzing unit for analyzing an external request signal to determine a distortion type and a correction condition of an image to be corrected, And a control unit for generating a control signal for adjusting the driving frequency of the driving signal according to the distortion type and the correction condition of the image.

At this time, the distortion type of the image is at least one of image distortion due to keystone and image distortion due to pin cushion, and the correction condition may be a frequency adjustment position and size of the driving signal.

The driving signal generating unit includes a memory unit for storing horizontal and vertical synchronizing signals for driving the optical scanner, a digital-to-analog converting unit for converting the horizontal and vertical synchronizing signals stored in the memory unit into analog signals, And a frequency adjuster for adjusting at least one of a frequency amplitude and an interval of the horizontal synchronizing signal stored in the memory unit according to the control signal, .

According to another aspect of the present invention, there is provided a method of correcting image distortion in a laser projection display, comprising: displaying the image by a light scanner driven by a driving signal; receiving an external request signal for image distortion correction; Analyzing a received external request signal to determine a distortion type and a correction condition of an image to be corrected; generating a control signal for adjusting a driving frequency for the driving signal according to a distortion type and a correction condition of the determined image; And adjusting the driving frequency of the driving signal in accordance with the generated control signal and generating and outputting the adjusted driving signal to the optical scanner.

Other objects, features and advantages of the present invention will become apparent from the detailed description of embodiments with reference to the accompanying drawings.

The laser projection display and the image distortion correction method according to the present invention have the following effects.

The present invention can easily and effectively correct image distortion such as keystone phenomenon and pin-cushion by controlling the angle of the optical scanner by finely adjusting the driving frequency of the optical scanner, thus complicated circuit implementation is not required.

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

1, the present invention includes a laser scanner 10, a driving frequency controller 30, a driving signal generator 50, a sensing unit (not shown) 70, a sensing signal processing unit 90, and a synchronization signal adjustment unit 110. [

Here, the optical scanner 10 is a micro-electro-mechenical system (MEMS) scanner, and is resonantly driven by a 90-degree phase shift driving signal.

The driving frequency control unit 30 receives and analyzes an external request signal for image distortion correction, and generates a control signal for driving frequency adjustment of the driving signal according to the analysis result.

2, the driving frequency control unit 30 includes a receiving unit 32, a signal analysis unit 34, and a control unit 36, as shown in FIG. 2, .

Here, the receiving unit 32 receives an external request signal for image distortion correction. The user may transmit a request signal wirelessly using a remote controller or the like, or may directly transmit a request signal through a distortion correction button The request signal may also be transmitted by wire.

Then, the signal analyzer 32 analyzes the external request signal received through the receiver 32, and determines the distortion type of the image to be corrected and the correction condition.

That is, the signal analyzer 32 analyzes the request signal to determine whether the request signal of the user is a request signal for image distortion correction by keystone or image distortion correction by pin-cushion And determines and determines a correction condition corresponding to the request signal.

Here, the correction condition means a frequency adjustment position and size of the drive signal. If the request signal is a request signal for correcting the image distortion due to the keystone, it is determined and determined whether or not the frequency amplitude adjustment position and size of the drive signal is information And if the request signal is a request signal for correcting the image distortion due to the pin-cushion, it is determined and determined whether or not the position and size of the frequency spacing adjustment position of the drive signal is information.

Next, the control unit 36 generates a control signal for adjusting the driving frequency for the driving signal according to the determined distortion type of the image and the correction condition.

Here, the controller 36 may generate at least one of a first control signal for adjusting the frequency amplitude of the driving signal and a second control signal for adjusting the frequency interval of the driving signal.

At this time, the first and second control signals may include frequency adjustment position and size information of the driving signal.

The driving signal generator 50 adjusts the driving frequency of the driving signal according to the generated control signal, and generates and outputs the adjusted driving signal to the optical scanner 10.

FIG. 3 is a view showing the drive signal generator of FIG. 1, and includes a memory unit 52, a digital-analog converter 54, a filter unit 56, and a frequency adjuster 58 as shown in FIG. .

The memory unit 52 includes a first memory unit 52a for storing a horizontal synchronizing signal for driving the optical scanner 10 and a second memory unit 52b for driving the optical scanner 10, And a second memory unit 52b for storing a synchronization signal.

The digital-to-analog conversion unit 54 includes a first digital-analog conversion unit 54a for converting a horizontal synchronizing signal stored in the first memory unit 52a into an analog signal, And a second digital-analog converter 54b for converting the synchronous signal into an analog signal.

Next, the filter unit 56 is a low pass filter composed of first and second filter units 56a and 56b, and removes high frequency components of the analog signal to generate a driving signal.

The frequency adjusting unit 58 adjusts at least one of the frequency amplitude and the interval of the horizontal synchronizing signal stored in the first memory unit 52a according to the control signal.

Depending on the case, at least one of the frequency amplitude and the interval of the vertical synchronization signal stored in the second memory unit 52b may be adjusted according to the control signal.

4, the frequency adjusting unit 58 adjusts the amplitude of the frequency of the horizontal synchronizing signal stored in the memory unit 52, according to the control signal, as shown in FIG. 4, An adjustment unit 58a and a frequency interval adjustment unit 58b for adjusting the frequency interval of the horizontal synchronization signal stored in the memory unit 52 according to the control signal.

The sensing unit 70 senses the driving of the optical scanner 10 and the sensing signal processing unit 90 processes the sensed sensing signal from the sensing unit 70.

Here, the sensing signal processing unit 90 includes a noise removing unit 92 and a clock signal converting unit 94. The noise removing unit 92 removes the noise of the sensing signal sensed by the sensing unit 70 And the clock signal converting unit 94 performs zero crossing on the sensing signal from which noise has been removed to convert the sensing signal into a clock signal.

The noise removing unit 92 may include a differential amplifying unit and an offset adjusting unit. The differential amplifying unit differential-amplifies the input sensing signal to remove noise, and the offset adjusting unit adjusts the differential amplified signal And adjusts the offset of the signal.

The synchronizing signal adjusting unit 110 may adjust the vertical and horizontal synchronizing signals of the input image according to the sensed sensing signals and synchronize them.

The image distortion correction method of the laser projection display according to the present invention is as follows.

9 is a flowchart illustrating a method for correcting image distortion of a laser projection display according to the present invention.

9, the optical scanner 10 is driven by a driving signal to display an image on a screen (S11)

At this time, the image displayed on the screen may show image distortion caused by the keystone phenomenon or may show image distortion due to the pin-cushion phenomenon.

Fig. 5 is a diagram showing image distortion caused by a keystone phenomenon. As shown in Fig. 5, a keystone phenomenon occurs due to the angle between the light scanner and the screen.

Generally, when the optical scanner is driven, the vertical drive is forcibly driven at about 60 Hz, and the horizontal drive is for resonance drive at about 18 KHz. The resonance drive is largely driven only at a specific frequency. do.

That is, due to the irregularity of the resonance drive of the optical scanner and the angle between the laser projection display and the screen, the upper part of the image displayed on the screen is wide, the lower part of the image is narrow, Occurs.

Fig. 7 is a view showing image distortion due to the pin-cushion phenomenon. As shown in Fig. 7, a pin-cushion phenomenon occurs due to the distance between the light scanner and the screen.

Generally, when the optical scanner is driven, the vertical drive is forcibly driven at about 60 Hz, and the horizontal drive is for resonance drive at about 18 KHz. The resonance drive is largely driven only at a specific frequency. do.

That is, due to the irregularity of the resonance drive of the optical scanner and the distance between the laser projection display and the screen, the image displayed on the screen is not horizontally aligned with the upper and lower sides and the left and right sides, A cushion phenomenon occurs.

Accordingly, the user operates the remote controller or the direct adjustment button of the display to transmit a distortion correction request signal such as a keystone and a pin-cushion.

Next, the receiving unit 32 of the driving frequency control unit 30 receives an external request signal for image distortion correction (S13)

The signal analysis unit 34 of the driving frequency control unit 30 analyzes the received external request signal to determine a distortion type and a correction condition of the image to be corrected (S15)

FIG. 10 is a flowchart for explaining step S15 of FIG. 9 in more detail. It is determined whether the request signal received from the receiver 32 is at least one of an image distortion correction signal by keystone and an image distortion correction signal by a pin cushion (S51)

As a result of the determination, if it is the keystone-based image distortion correction signal, it is determined whether the frequency amplitude adjustment position and size of the drive signal are information (S53)

Then, if there is information, the information is transmitted to the controller 36 (S55). If there is no information, the operation is terminated after a predetermined time.

However, if it is determined that the signal is not an image distortion correction signal due to a keystone, it is determined whether it is an image distortion correction signal due to a pin-cushion (S57)

As a result of the determination, if it is the image distortion correction signal by the pin cushion, it is determined whether or not the position and the size of the frequency interval adjustment position of the drive signal are information (S59)

Then, if there is information, the information is transmitted to the controller 36 (S55). If there is no information, the operation is terminated after a predetermined time.

However, if it is determined that the signal is not the image distortion correction signal due to the pin-cushion, the operation ends after a predetermined time.

On the other hand, the control unit 36 generates a control signal for adjusting the driving frequency for the driving signal in accordance with the determined distortion type of the image and the correction condition (S17)

Next, the driving signal generator 50 adjusts the driving frequency of the driving signal according to the generated control signal, and generates the adjusted driving signal to output to the optical scanner 10.

That is, the driving signal generating unit 50 stores the horizontal and vertical synchronizing signals for driving the optical scanner in the memory unit 52, and the frequency adjusting unit 58 adjusts the frequency of the stored horizontal synchronizing signal Adjust at least one of the amplitude and the interval.

The driving signal generating unit 50 converts the horizontal and vertical synchronizing signals adjusted by the digital-analog converting unit 54 into analog signals, removes the high-frequency components of the analog signals by the filter unit 56, And outputs the generated drive signal to the optical scanner.

FIG. 6A is a view showing a horizontal drive cycle of the light scanner by a general drive signal, and FIG. 6B is a diagram illustrating a horizontal drive cycle of the light scanner by the keystone distortion correction drive signal.

As shown in FIG. 6A, the optical scanner 10 is driven by a drive signal having the same frequency as the entire region when implementing one frame image constituting one screen. However, as shown in FIG. 6B, Is driven by the adjusted drive signal, the keystone distortion image can be corrected.

That is, as shown in FIG. 5, when the upper portion of the image displayed on the screen is wide and the lower portion of the image is narrow, the amplitude of the frequency is reduced when the optical scanner implements the upper portion of the image, and the amplitude of the frequency is increased when the portion of the image is implemented.

In addition, when the upper part of the image displayed on the screen is narrower and the lower part of the image is wider, the amplitude of the frequency is increased when the optical scanner implements the upper part of the image, and the amplitude of the frequency is lowered when the lower part of the image is implemented.

8A is a view showing a horizontal driving cycle of a light scanner by a general driving signal, and FIG. 8B is a diagram illustrating a horizontal driving cycle of a light scanner by a pin-cushion distortion correcting driving signal.

As shown in FIG. 8A, the optical scanner 10 is driven by a drive signal having the same frequency as the entire area when implementing one frame image constituting one screen, but considering an area where pin-cushion distortion occurs as shown in FIG. 8B The pin-cushion distortion image can be corrected by driving with the drive signal whose frequency is adjusted.

That is, as shown in FIG. 7, when the image displayed on the screen is bent from the edge to the center area, when the optical scanner implements the edge area of the image, the interval of the frequency is narrowed, Spread.

As described above, the present invention for correcting image distortion can easily and effectively correct distortion of an image such as a keystone phenomenon and a pin-cushion by controlling the angle of a light scanner by finely adjusting a driving frequency of a light scanner, No implementation is required.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments but should be determined according to the claims.

1 is a view showing a laser projection display according to the present invention;

Fig. 2 is a view showing the driving frequency control unit of Fig. 1

3 is a view showing the drive signal generator of FIG.

4 is a view showing the frequency adjusting section of Fig. 3

5 is a view showing an image distortion due to a keystone phenomenon

6A is a view showing a horizontal driving cycle of the optical scanner by a general driving signal

6B is a diagram showing a horizontal drive cycle of the light scanner by the keystone distortion correction drive signal

7 is a view showing an image distortion due to a pin-cushion phenomenon

8A is a view showing a horizontal driving cycle of the optical scanner by a general driving signal

8B is a view showing a horizontal driving cycle of the light scanner by the pin-cushion distortion correcting drive signal

9 is a flowchart for explaining a method of correcting image distortion of a laser projection display according to the present invention.

10 is a flow chart for explaining step S15 of FIG. 9 in more detail.

Claims (12)

1. A laser projection display for scanning an image on a screen, An optical scanner driven by a driving signal; A drive frequency control unit for receiving and analyzing an external request signal for distortion correction of the image and generating a control signal for adjusting a drive frequency for the drive signal according to the analysis result; And, A driving signal generator for adjusting a driving frequency of the driving signal according to the generated control signal, generating the adjusted driving signal, and outputting the adjusted driving signal to the optical scanner; A sensing unit for sensing driving of the optical scanner; A noise removing unit for removing a noise of a sensing signal sensed from the sensing unit, and a clock signal converting unit for converting the noise-removed sensing signal into a clock signal, wherein the sensing unit senses the sensing signal from the sensing unit, A signal processor; And And a synchronization signal adjustment unit adjusting and synchronizing vertical and horizontal synchronization signals of the input image according to the signal processing signal. The apparatus of claim 1, wherein the driving frequency control unit comprises: A receiver for receiving an external request signal for distortion correction of the image; A signal analyzer for analyzing the external request signal to determine a distortion type and a correction condition of the image to be corrected; And a controller for generating a control signal for adjusting a driving frequency for the driving signal according to the determined distortion type and correction condition of the image. The image pickup apparatus according to claim 2, wherein the distortion type of the image is at least one of image distortion due to keystone and image distortion due to pin-cushion, and the correction condition is a frequency adjustment position and size of the drive signal Laser projection display. 3. The apparatus of claim 2, wherein the controller generates at least one of a first control signal for adjusting the frequency amplitude of the driving signal and a second control signal for adjusting the frequency interval of the driving signal Laser projection display. The laser projection display according to claim 4, wherein the first and second control signals include frequency adjustment position and size information of the drive signal. The driving method according to claim 1, A memory unit for storing horizontal and vertical synchronizing signals for driving the optical scanner; A digital-analog converter for converting the horizontal and vertical synchronizing signals stored in the memory into analog signals; A filter unit for removing a high frequency component of the analog signal to generate a driving signal and outputting the driving signal to the optical scanner; And a frequency adjustment unit adjusting at least one of a frequency magnitude and an interval of the horizontal synchronous signal stored in the memory unit according to the control signal. 7. The apparatus of claim 6, A frequency amplitude adjusting unit for adjusting a frequency amplitude of the horizontal synchronizing signal stored in the memory unit according to the control signal, And a frequency interval adjusting unit for adjusting a frequency interval of the horizontal synchronizing signal stored in the memory unit according to the control signal. The apparatus according to claim 1, A differential amplifier for differentially amplifying a sensing signal to remove noise; And And an offset adjustment unit for adjusting an offset of the differential amplified signal. delete delete delete delete

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