KR20110016631A - Laser projection display and method for compensating image distortion of the same - Google Patents

Abstract

PURPOSE: A laser projection display and an image distortion compensating method thereof are provided to compensate the distortion of a displayed image by controlling the angle of an optical scanner by fine adjusting the driving frequency. CONSTITUTION: A laser projection display scanning comprises a optical scanner driven by a driving signal, a driving frequency controller which receives the request signal for compensation from the outside(S13), analyze(S15), and generating the control signal for adjusting the driving frequency(S17). A driving signal generator adjusts the driving frequency(S19) and generates the driving signal to be outputted to the optical scanner.

Description

Laser projection display and method for compensating image distortion of the same}

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, along with the rapid advancement into the multimedia society, large-sized and high-definition display screens are required, and in recent years, in addition to high resolution, the implementation of natural natural colors is important.

In order to achieve perfect natural colors, it is necessary to use a light source with high color purity, such as a laser. One of the devices for realizing an image using a laser is a laser projection display using an optical scanner.

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

In the case of the optical scanner, the driving speed should be high in order to implement a high resolution image.

That is, the high driving speed of the optical scanner means that the driving angle of the optical scanner should be large.

In the optical scanner, when the driving signal is a specific frequency, the driving angle tends to be large. The specific frequency of the driving signal that increases the driving angle of the optical scanner is called a resonance frequency.

Therefore, when the driving signal corresponds to the resonant frequency, the optical scanner has the largest driving angle and enables high speed driving.

However, since the laser projection display scans the light generated from the laser light source on the screen using an optical scanner, various image distortions may occur due to the distance or angle to the screen.

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

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser projection display and a method for correcting image distortion thereof, which can correct distortion of a displayed image by controlling the angle of the optical scanner by finely adjusting the driving frequency of the optical scanner.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above are clearly understood by those skilled in the art from the following descriptions. Could be.

The laser projection display according to the present invention receives and analyzes an optical scanner driven by a drive signal and an external request signal for distortion correction of an image, and controls for adjusting a drive frequency for the drive signal according to the analysis result. And a drive signal generator for adjusting a drive frequency of the drive signal according to the generated control signal, and generating and outputting the adjusted drive signal to the optical scanner.

Here, the driving frequency controller may include a receiver configured to receive an external request signal for distortion correction of an image, a signal analyzer configured to analyze the external request signal and determine a distortion type and a correction condition of the image to be corrected, and The controller may be configured to generate a control signal for adjusting the driving frequency of the driving signal according to the distortion type and the correction condition of the image.

In this case, the distortion type of the image may be at least one of an image distortion by a keystone and an image distortion by a pin cushion, and the correction condition may be a frequency adjusting position and a magnitude of the driving signal.

The driving signal generator may include a memory unit for storing horizontal and vertical synchronization signals for driving the optical scanner, a digital-to-analog converter for converting horizontal and vertical synchronization signals stored in the memory unit into an analog signal, and an analog signal. A filter unit for generating a driving signal by removing a high frequency component and outputting the driving signal to the optical scanner, and a frequency adjusting unit for adjusting at least one of a frequency amplitude and an interval of the horizontal synchronization signal stored in the memory unit according to a control signal. Can be.

On the other hand, the image distortion correction method of the laser projection display according to the present invention comprises the steps of displaying the image by an optical scanner driven by a drive signal, receiving an external request signal for distortion correction of the image, Analyzing the received external request signal, determining the distortion type and correction condition of the image to be corrected, and generating a control signal for adjusting the driving frequency for the driving signal according to the distortion type and correction condition of the determined image. And adjusting the driving frequency of the driving signal according to the generated control signal, and generating the adjusted driving signal and outputting the adjusted driving signal to the optical scanner.

Other objects, features and advantages of the invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

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

The present invention can control the angle of the optical scanner by finely adjusting the driving frequency of the optical scanner, so that distortion of an image such as a keystone phenomenon and a pin-cushion can be corrected simply and effectively, thereby eliminating the need for complicated circuit implementation.

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

1 is a view illustrating a laser projection display according to the present invention. As shown in FIG. 1, the present invention provides an optical scanner 10, a driving frequency controller 30, a driving signal generator 50, and a sensing unit ( 70), the sensing signal processor 90, and the synchronization signal controller 110 may be configured.

Here, the optical scanner 10 is a MEMS (micro-electro-mechenical system) scanner, and resonantly drives by a drive signal shifted by 90 degrees.

In addition, the driving frequency controller 30 receives and analyzes an external request signal for distortion correction of an image, and generates a control signal for adjusting the driving frequency of the driving signal according to the analysis result.

FIG. 2 is a diagram illustrating the driving frequency controller of FIG. 1, and as shown in FIG. 2, the driving frequency controller 30 may include a receiver 32, a signal analyzer 34, and a controller 36. Can be.

Here, the receiver 32 serves to receive an external request signal for distortion correction of an image, and a user may transmit a request signal wirelessly using a remote controller or the like, or directly through a distortion correction button on a display. The request signal may be transmitted by wire.

Subsequently, the signal analyzer 32 analyzes an external request signal received through the receiver 32 to determine a distortion type and the correction condition of the image to be corrected.

That is, the signal analyzer 32 analyzes the request signal to determine whether the user's request signal is a request signal for correcting image distortion by a keystone or correcting image distortion by pin-cushion. Determine whether the signal is a request signal, and determine and determine a correction condition corresponding thereto.

Here, the correction condition refers to the frequency adjustment position and magnitude of the drive signal. If the request signal is a request signal for image distortion correction by the keystone, it is determined and determined whether the information on the frequency amplitude adjustment position and magnitude of the drive signal is determined. If the request signal is a request signal for correcting image distortion by pin-cushion, it is determined and determined whether or not information on the frequency spacing adjustment position and size of the driving signal is provided.

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

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.

In this case, the first and second control signals may include frequency adjusting position and magnitude information of the driving signal.

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

FIG. 3 is a view illustrating the driving signal generator of FIG. 1, and as shown in FIG. 3, includes a memory 52, a digital-to-analog converter 54, a filter 56, and a frequency adjuster 58. Can be configured.

Here, the memory unit 52 is a look up table, and the first memory unit 52a storing the horizontal synchronization signal for driving the optical scanner 10 and the vertical for driving the optical scanner 10. The second memory unit 52b may store a synchronization signal.

In addition, the digital-to-analog converter 54 converts the horizontal synchronization signal stored in the first memory 52a into an analog signal, and the vertical stored in the second memory 52b and the first digital-analog converter 54a. The second digital-analog converter 54b converts the synchronization signal into an analog signal.

Next, the filter unit 56 is a low pass filter, which is composed of first and second filter units 56a and 56b, and generates a driving signal by removing high frequency components of the analog signal.

Next, 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.

In some cases, 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 is a diagram illustrating the frequency adjuster of FIG. 3. As shown in FIG. 4, the frequency adjuster 58 adjusts a frequency amplitude of a horizontal synchronization signal stored in the memory 52 according to a control signal. And 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.

Meanwhile, the sensing unit 70 senses the driving of the optical scanner 10, and the sensing signal processing unit 90 processes the sensing signal sensed by the sensing unit 70.

Here, the sensing signal processor 90 includes a noise remover 92 and a clock signal converter 94. The noise remover 92 removes noise of the sensing signal sensed by the sensor 70. The clock signal converter 94 performs a zero crossing on the sensing signal from which noise is removed and converts the detected signal into a clock signal.

In addition, although not shown, the noise removing unit 92 may be configured to include a differential amplifier and an offset adjusting unit. The differential amplifier unit may differentially amplify an input sensing signal to remove noise, and the offset adjustment unit may differentially amplify the signal. It serves to adjust the offset of.

In addition, the synchronization signal adjusting unit 110 may serve to synchronize the vertical and horizontal synchronization signals of the input image according to the signal processed sensing signals.

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

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

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

In this case, the image displayed on the screen may show image distortion due to keystone phenomenon or image distortion due to pin-cushion phenomenon.

FIG. 5 is a diagram illustrating image distortion caused by a keystone phenomenon. As shown in FIG. 5, a keystone phenomenon occurs by an angle between an optical scanner and a screen.

In general, when the optical scanner is driven, the vertical drive is forcibly driven at about 60 Hz, and the horizontal drive is driven at about 18 KHz. The resonance drive is driven only at a specific frequency, and the driving operation is reduced at other frequencies. do.

That is, due to the irregularity of the resonance driving of the optical scanner and the angle between the laser projection display and the screen, a keystone phenomenon in which the upper portion of the image displayed on the screen is wide and the lower portion of the image is narrow, or the upper portion of the image is narrow and the lower portion of the image is wide Occurs.

FIG. 7 is a diagram illustrating image distortion caused by a pin-cushion phenomenon. As shown in FIG. 7, the pin-cushion phenomenon occurs due to the distance between the optical scanner and the screen.

In general, when the optical scanner is driven, the vertical drive is forcibly driven at about 60 Hz, and the horizontal drive is driven at about 18 KHz. The resonance drive is driven only at a specific frequency, and the driving operation is reduced at other frequencies. do.

In other words, due to the irregularity of the resonance driving of the optical scanner and the distance between the laser projection display and the screen, the upper / lower side and the left / right side of the image displayed on the screen are not horizontal, but are bent from the edge to the center region. Cushioning occurs.

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

Next, the receiver 32 of the driving frequency controller 30 receives an external request signal for distortion correction of an image (S13).

Subsequently, the signal analyzer 34 of the driving frequency controller 30 analyzes the received external request signal to determine the distortion type and the correction condition of the image to be corrected.

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

As a result of the determination, if the image distortion correction signal is generated by the keystone, it is determined whether or not the information on the frequency amplitude adjustment position and magnitude of the driving signal is informed (S53).

Subsequently, if there is information, the information is transmitted to the control unit 36 (S55). If there is no information, the operation ends after a predetermined time.

However, if it is determined that the image distortion correction signal is not caused by the keystone, it is determined whether the image distortion correction signal is caused by the pin-cushion (S57).

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

Subsequently, if there is information, the information is transmitted to the control unit 36 (S55). If there is no information, the operation ends after a predetermined time.

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

On the other hand, the controller 36 generates a control signal for adjusting the driving frequency for the driving signal according to the determined distortion type and correction condition of the image.

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

That is, the driving signal generation unit 50 stores the horizontal and vertical synchronization signals for driving the optical scanner in the memory unit 52, and the frequency adjusting unit 58 stores the frequency of the stored horizontal synchronization signals according to the generated control signal. Adjust at least one of amplitude and spacing.

The driving signal generator 50 converts the horizontal and vertical synchronizing signals adjusted by the digital-analog converter 54 into analog signals, and removes and operates the high frequency components of the analog signals by the filter 56. A signal is generated and the generated driving signal is output to the optical scanner.

FIG. 6A is a diagram illustrating a horizontal drive cycle of an optical scanner by a general drive signal, and FIG. 6B is a diagram illustrating a horizontal drive cycle of an optical scanner by a keystone distortion correction drive signal.

When the optical scanner 10 implements a single frame image constituting one screen as shown in FIG. 6A, the entire scanner is driven with a driving signal having the same frequency. However, as shown in FIG. 6B, the optical scanner 10 takes into account the area where keystone distortion occurs. By driving with 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 lower portion of the image is implemented.

In addition, when the upper portion of the image displayed on the screen is narrow and the lower portion of the image is wide, the amplitude of the frequency is increased when the optical scanner implements the upper portion of the image, and the amplitude of the frequency is reduced when the lower portion of the image is implemented.

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

When the optical scanner 10 implements a 1-frame image constituting one screen, as shown in FIG. 8A, the entire area is driven by a driving signal having the same frequency. However, as shown in FIG. 8B, the optical scanner 10 considers an area where pin-cushion distortion occurs. Therefore, 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 region, when the optical scanner implements the image edge region, the frequency interval is narrowed, and when the image center region is implemented, the frequency interval is adjusted. Widen.

As described above, the present invention of correcting image distortion finely adjusts the driving frequency of the optical scanner to control the angle of the optical scanner, so that the distortion of the image such as keystone phenomenon and pin-cushion can be easily and effectively corrected, and thus, a complicated circuit. 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 defined by the claims.

1 shows a laser projection display according to the invention

2 is a view illustrating a driving frequency controller of FIG. 1;

3 is a view illustrating a driving signal generator of FIG. 1;

4 is a view illustrating a frequency adjuster of FIG.

5 is a diagram illustrating image distortion caused by a keystone phenomenon.

6A is a view illustrating a horizontal driving cycle of an optical scanner by a general driving signal;

6B is a view showing a horizontal driving cycle of the optical scanner by the keystone distortion correction drive signal;

7 is a view illustrating image distortion caused by a pin-cushion phenomenon

8A is a view illustrating a horizontal driving cycle of an optical scanner by a general driving signal;

8B is a view showing a horizontal driving cycle of the optical scanner by the pin-cushion distortion correction drive signal;

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

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

Claims (12)

In a laser projection display for scanning an image on a screen, An optical scanner driven by a drive signal; A driving frequency controller configured to receive and analyze an external request signal for correcting distortion of the image, and generate a control signal for adjusting a driving frequency of the driving signal according to the analysis result; And, And a driving signal generator for adjusting the driving frequency of the driving signal according to the generated control signal and generating the adjusted driving signal and outputting the adjusted driving signal to the optical scanner. The method of claim 1, wherein the driving frequency control unit, A receiver which receives an external request signal for distortion correction of the image; A signal analyzer configured to analyze the external request signal and determine a distortion type of the image to be corrected and the correction condition; And a controller configured to generate a control signal for adjusting a driving frequency of the driving signal according to the determined distortion type and the correction condition of the image. The method of claim 2, wherein the distortion type of the image is at least one of an image distortion by a keystone and an image distortion by a pin-cushion, and the correction condition is a frequency adjusting position and magnitude of the driving signal. Laser projection display. The method of claim 2, wherein the control unit, characterized in that for generating at least one of the first control signal for adjusting the frequency amplitude of the drive signal and the second control signal for adjusting the frequency interval of the drive signal. Laser projection display. The laser projection display of claim 4, wherein the first and second control signals include frequency adjusting position and magnitude information of the driving signal. The method of claim 1, wherein the driving signal generator, A memory unit for storing horizontal and vertical synchronization signals for driving the optical scanner; A digital-analog converter for converting horizontal and vertical synchronization signals stored in the memory unit into analog signals; A filter unit which generates a driving signal by removing a high frequency component of the analog signal and outputs the driving signal to the optical scanner; And a frequency adjusting unit for adjusting at least one of a frequency amplitude and an interval of the horizontal synchronizing signal stored in the memory unit in accordance with the control signal. The method of claim 6, wherein the frequency adjustment unit, A frequency amplitude adjustment unit for adjusting the frequency amplitude of the horizontal synchronization signal stored in the memory unit according to the control signal; And a frequency interval adjusting unit for adjusting a frequency interval of a horizontal synchronization signal stored in the memory unit in accordance with the control signal. The apparatus of claim 1, further comprising: a sensing unit configured to sense driving of the optical scanner; A sensing signal processor configured to process a sensing signal sensed by the sensing unit; And a synchronizing signal adjusting unit configured to adjust and synchronize the vertical and horizontal synchronizing signals of the input image according to the signal processed sensing signal. The method of claim 8, wherein the sensing signal processing unit, A noise removing unit removing noise of the sensing signal sensed by the sensing unit; And a clock signal converting unit converting the noise-sensed sensing signal into a clock signal. An image distortion correction method of a laser projection display for scanning an image on a screen, Displaying the image by an optical scanner driven by a drive signal; Receiving an external request signal for distortion correction of the image; Analyzing the received external request signal to determine a distortion type of the image to be corrected and the correction condition; Generating a control signal for adjusting a driving frequency of the driving signal according to the determined distortion type and correction condition of the image; And, And adjusting the 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. The method of claim 10, wherein the determining of the distortion type and the correction condition of the image to be corrected by analyzing the received external request signal comprises: Determining whether the request signal is at least one of an image distortion correction signal by a keystone and an image distortion correction signal by a pin cushion; As a result of the determination, if the image distortion correction signal by the keystone is determined whether the information on the frequency amplitude adjustment position and magnitude of the drive signal, and if the image distortion correction signal by the pin-cushion, frequency interval of the drive signal Determining whether information on the adjustment position and the size; And if the information is present, transmitting the information, and if the information is absent, terminating the operation after a predetermined time. The method of claim 10, wherein adjusting the 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 includes: Storing horizontal and vertical synchronization signals for driving the optical scanner; Adjusting at least one of a frequency amplitude and an interval of the stored horizontal synchronization signal according to the generated control signal; Converting the adjusted horizontal and vertical synchronization signals into analog signals; Generating a driving signal by removing a high frequency component of the analog signal; And outputting the generated driving signal to the optical scanner.

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