KR0136842B1 - Color wheel for projector and apparatus for controlling the same - Google Patents

Abstract

The present invention relates to a color wheel of a projection image display system and a control device thereof, wherein one rotation period corresponds to five vertical synchronization signal periods in a color image signal, and the R, G, and B colors of the color image signal are defined. R, G, B color filter areas 2a, 3a, 4a are equally divided for the period of each vertical synchronization signal to obtain light, and R divided for the period (1V) of the one vertical synchronization signal. The rotation angle of the G-B color filter areas 2a, 3a, 4a is set to 72 °; Rotational speed detection means (17, 18) for detecting the rotational speed of the electric motor (M) for driving the color wheel (1) to separate the light irradiated from the light source to obtain R, G, B color light, and the reference phase signal Phase comparison means (12, 14, 15) for detecting the phase difference by comparing the phase reference signal provided from the generating means (10, 11) with the phase of the electric motor (M) for rotating the color wheel (1), the rotation An adder 19 which obtains an error value from the rotational speed detected by the speed detecting means 17 and 18 and the phase value detected by the phase comparing means 12, 14 and 15, and the error value detected by the adder 19 And a motor driving means 23 for driving the electric motor M by amplifying the PWM-modulated compensation value by the error compensating unit 20. The color wheel 1 is rotated synchronously during the rising period of the vertical synchronous signal separated from the color image signal. It is adapted to display R · G · B color signal of the image.

Description

Color Wheel of Projection Image Display System and Its Control Device

1 is a diagram for explaining the configuration of a color wheel of a projection image display system according to the present invention;

FIG. 2 is a block diagram showing a color wheel control apparatus of a projection image display system according to the present invention for controlling the color wheel shown in FIG.

3A and 3B show the configuration of the color wheel of a conventional general projection image display system.

* Description of the symbols for the main parts of the drawings *

1 Color Wheel 10 Vertical Sync Signal Separator

11: vertical synchronization signal counter 12: phase comparison unit

13,16 buffer 14,18 low pass filter (LPF)

15 loop filter 17 rotation speed detection unit

19: Adder 20: Error compensator

21: amplification section 22: error gate section

23: motor drive unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color wheel applicable to a projection type image display system and a control device thereof, and more particularly to R, G, and B, having one rotation period corresponding to a plurality of vertical synchronization signals such as five of color image signals. R, G, B color by single color wheel by rotating color wheel to obtain color light and rotating it at constant linear speed in synchronism with rising time of vertical synchronous signal separated from color image signal The present invention relates to a color wheel control device of a projection image display system for controlling to obtain light.

In general, a CRT apparatus employed in a direct view type image display system has an R, G, B fluorescent point formed on a fluorescent panel, a black stripe is formed, and electrons emitted corresponding to a color image signal from an R, G, B electron gun. When the beam passes through the shadow mask and reaches a specific R, G, B fluorescent point, the corresponding fluorescent point emits light to display color.

However, since the CRT device must be provided with R, G, and B fluorescent points for one pixel of the color image, the overall size of the CRT device becomes large, while the size of the displayable screen is inevitably limited.

On the other hand, according to the projection type image display system employing a so-called AMA (Actuated Mirror Array) device which acts to modulate or adjust the light path of the incident light when a voltage corresponding to the image signal of the color image is applied, the light emitted from the light source is fixed. A source stop member shaped into a pattern, a field lens for collecting light shaped through a source stop member in a predetermined pattern, and the light collected from the field lens at a reflection angle corresponding to the R, G, and B colors of the image signal. A light modulation member by a reflecting AMA device, a projection stop member for positioning light reflected by the light modulation member to form an image on a screen, and a projection lens for displaying the light transmitted through the projection stop member on a screen. do.

As is well known, in the light modulating member of such a projection type image display system, a color display device is required for displaying R, G, and B color light of a color image. An example of such a color display device is R, G, A-plate color display system employing AMA channels (typically corresponding to R, G, B-colored light) and R, G, B color filters in front of each AMA panel, and a single-color color wheel A single-plate color display method for forming R, G, and B color filter areas in the region to control the rotation angle of the color wheel to obtain R, G, and B color light is applied.

Among them, in the method of applying the light modulation member by the AMA panel corresponding to the R, G, B color filter, when a voltage corresponding to the R, G, B signal of the color image is applied to the corresponding AMA panel, In the corresponding AMA panel, the angle of reflection for the light transmitted through each of the R, G, and B color filters is determined to obtain each of the R, G, and B color lights. An optical modulation module including an AMA panel for modulating the amount of light corresponding to the R, G, and B signals of the image must be provided in at least three plates, which not only increases the price of the overall image display system but also increases the color image. There is a disadvantage that the defect mirror (Defect Mirror) is increased by about three times as compared to the color wheel method using a single AMA panel at the time of display, and the image quality deteriorates.

On the other hand, according to the color display method employing the color wheel, the color wheel is rotated in response to the R, G, B signal of the color image by appropriate driving means including an electric motor, and R, G, B from the light emitted from the light source. The color wheel applied to such a projection type image display system receives a beam shot of white light emitted from a light source as shown in FIG. A color wheel is provided as a rotation filter which performs rotation corresponding to the B signal.

On the other hand, such a color wheel divides a single R filter region 24a, G filter region 24b, and B filter region 24c into constant regions, respectively, for the optical filter operation corresponding to the R, G, and B signals of the color image. The beam shot region 26 irradiated from the light is present in any one of the R, G, and B filter regions 24a, 24b, and 24c.

Here, the beam shot region 26 existing on the R, G, and B filter regions 24a, 24b, and 24c of the color wheel is generally formed in a much smaller size than the respective filter regions. As described above, the color wheel including the R, G, B filter regions 24a, 24b, 24c is rotated in the AA direction by the driving means, so that the beam shot region 26 has the R, G, B filter for reproduction of the color image. In the case where the synchronization portion for the color image corresponds to, for example, the boundary portion between the G filter region 24b and the B filter region 24c in the state of moving over the regions 24a, 24b, 24c, The predetermined area 26a located in the G filter area 24b acts as color noise of the projected image, resulting in deterioration in image quality.

Therefore, in the state where R, G, B color light is obtained by such a color wheel, a new type of color wheel is required in order to prevent deterioration of color image quality, and driving of the color wheel accurately synchronized with the R, G, B signal of the color image. The way is required.

Accordingly, the present invention has been made in view of the above circumstances, and its main object is region division so as to correspond to five vertical synchronization signals of a color image in one rotation, and R, G, and B colors of color images in each division section. A color wheel of a projection image display system is provided in which a color filter area is set to obtain light.

Another object of the present invention is to vertically synchronize a color wheel in which one rotation is divided so as to correspond to five vertical synchronization signals of a color image and a color filter area is formed so as to obtain R, G, and B color light in each division section. It is an object of the present invention to provide a color wheel control device of a projection type image display system which is capable of obtaining accurate R, G, and B color light by a single-plate color wheel by synchronously rotating the signal during a signal rising period.

In order to achieve the above object, according to a preferred example of the present invention, it is generally defined as one rotation in five vertical synchronization signal periods in a color image, and each vertical synchronization to obtain R, G, B color light of the color image. The R, G, B color filter area is equally divided with respect to the period of the signal, and a color wheel of the projection image display apparatus is defined, which is defined to rotate by an angle of approximately 72 ° in the period of at least one vertical synchronization signal.

According to another preferred embodiment of the present invention, the rotational speed detection means for detecting the rotational speed of the electric motor for driving the color wheel to separate the light irradiated from the light source to obtain the R, G, B color light, and reference phase signal generating means A phase comparison means for comparing a phase reference signal provided from the phase of the electric motor for rotating the color wheel to detect a phase value, an error value from a rotation speed detected by the rotation speed detection means and a phase difference detected by the phase comparison means. An error detecting means obtained, a modulation means for modulating a pulse width (PWM) to compensate for the error value detected by the error detecting means, and a motor driving means for driving the electric motor for the color wheel by amplifying the compensation value modulated by the modulation means. It is configured to include.

Preferably, the color wheel is configured to color display five vertical synchronization signals of the color image in one rotation period.

The reference phase signal generating means generates a reference phase signal by counting a rising period of the vertical synchronous signal separation unit for separating the vertical synchronous signal from the color image signal and the vertical synchronous signal separated by the vertical synchronous signal separation unit. It consists of a vertical synchronization signal counter.

The phase comparing unit compares the reference phase signal with the phase signal of the electric motor to detect a difference and a low pass filter for low pass filtering the phase difference detected by the phase comparing unit and the low pass filtered phase difference. It consists of a loop filter that filters for loop stabilization.

The rotational speed detection means includes a speed detection unit that detects a frequency signal corresponding to the rotation of the electric motor driving the color wheel as a voltage signal and obtains a speed signal, and a low pass filter that low-pass filters the speed signal obtained by the speed detection unit. It is composed.

The error detecting means comprises an adder which adds the phase difference with respect to the phase of the electric motor driving the color wheel and the speed detected by the rotational speed detecting means and detects error values with respect to the phase and speed.

According to the color wheel of the projection type image display system and the control apparatus thereof according to the present invention, the color wheel is defined to have one rotation cycle synchronously with the five vertical synchronization signals of the color image signal, and the driving is performed. By detecting the frequency signal and the phase of the motor and controlling the color wheel synchronously during the rise period of the vertical synchronous signal, the R, G, B color light can be obtained by a single AMA panel, and the color image can be displayed.

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

1 is a view for explaining a color wheel of a projection type image display system according to the present invention, in which a disc-shaped color wheel denoted by reference numeral 1 is generally defined to rotate one rotation in five vertical synchronization signal periods in a color image, and a color image. In order to obtain R, G, and B color light, the R, G, B color filter regions 2a, 3a, and 4a are equally divided in the period (1V) of one vertical synchronization signal, and one vertical synchronization signal is obtained. The rotation angle of the R, G, and B color filter areas 2a, 3a, and 4a that rotate in the period (1V) is defined as an angle of about 72 ° when one rotation of the disc-shaped color wheel 1 is 360 °. do.

According to the same figure, the beam shot region 1a by the beam shot of the white light emitted from the light source has a size corresponding to the area size of each of the R, G, and B color filter regions 2a, 3a, and 4a. .

Therefore, according to the color wheel 1 shown in FIG. 1, the color of the R, G, and B colors is obtained so as to obtain R, G, B color light by rotating in the angle range of 72 ° in the period (1V) of one vertical synchronization signal. The filter areas 2a, 3a, 4a are evenly arranged, so that the R, G, B filter areas 2a, 3a, 4a corresponding to the period of each vertical synchronization signal have one rotation period of the corresponding color wheel 1 The area is repeatedly divided so that 5 vertical synchronization signals are covered at, and in this case, the cycle of one rotation of the color wheel 1 is

1V = 59.94Hz → T = 16.683msec

5 × T = 83.416msec

∴ rpm = 1 / 5T × 60sec = 719.28... → 11.988 Hz

∴ PG pulse; 11.988 Hz

FG pulse; 143.856 Hz

It becomes

2 is a block diagram of a color wheel control apparatus according to the present invention which performs control of the color wheel 1 shown in FIG. 1. Reference numerals 10 and 11 denote color image signals while forming reference phase signal generating means. A vertical synchronous signal separation unit for receiving and detecting the vertical synchronous signal and counting a rising edge of the vertical synchronous signal detected by the vertical synchronous signal separation unit 10 to generate a counting result. Indicates a counter.

Further, reference numeral 12 denotes a phase generated from an electric motor M which drives the color wheel 1 while constituting the phase detecting means (preferably composed of a drum motor employed as an electric motor in an 8mm camcorder, for example). Receives the signal PG via the buffer 13 and compares the count result of the rising period of the vertical synchronous signal of the color image signal provided by the vertical synchronous signal counter 11 of the reference phase signal generating means to compare the phase difference. Denotes a phase comparator for detecting a signal, and 14 and 15 together with the phase comparator 12 constitute a phase comparator, and a low range of the phase difference based on the rising period of the vertical synchronization signal detected by the phase comparator 12; A low pass filter (LPF) for filtering through a pass filter and a loop filter for performing loop filtering for stabilization of a loop with respect to a phase difference low pass filtered by the low pass filter 14 are shown.

Reference numeral 16 denotes a buffer for buffering and outputting the frequency signal FG generated from the electric motor M driving the color wheel 1, and 17 and 18 designate the buffer ( 16 shows a rotational speed detector for detecting a speed by converting the frequency signal buffered and outputted into a voltage signal and a low pass filter (LPF) for low-pass filtering the speed voltage signal detected by the rotational speed detector.

Reference numeral 19 denotes an adder which serves as an error detecting means for detecting an error value by adding a phase difference provided from the loop filter 15 and a rotation speed signal provided through the low pass filter 18. An error compensator for providing a compensation signal for an error detected by the adder 19 as a PWM modulation signal is shown. 21 denotes an error compensating signal output from the error compensator 20 to amplify the error gate part 22. The amplification part 21 applied to the motor drive part 23 is shown.

According to the color wheel and the control apparatus of the projection type image display system according to the present invention configured as described above, the color image signal is applied to the vertical synchronous signal separator 10 so that the vertical synchronous signal is detected and synchronized with the rising edge of the vertical synchronous signal. The PG signal, which is information on the head phase, from the electric motor M driving the color wheel 1 in the state where the reference phase signal is applied to the phase comparator 12 in the vertical synchronization signal counter 11 When the phase comparator 12 is applied to the phase comparator 12, the phase comparator 12 compares the phase of the PG signal with respect to the reference phase signal to obtain a phase difference signal, and the phase difference signal is a low pass filter ( 14 is applied to the low pass filtering (DC leveling) and then to the loop filter 15.

On the other hand, when the frequency signal FG relating to the rotational speed of the color wheel 1 from the electric motor M driving the color wheel 1 is applied to the rotational speed detection unit 17 via the buffer 16, the rotation thereof is rotated. The speed detector 17 converts the frequency signal FG into a voltage signal and applies it to the low pass filter 18. The voltage signal applied to the low pass filter 18 is subjected to low pass filtering (DC leveling). And then added in the phase difference signal and adder 19 and detected as an error value signal.

The error value signal detected by the adder 19 is applied to the error compensator 20, PWM modulated and then amplified by the amplifier 21, and applied to the motor driver 23 via the error gate 22. . The motor driving unit 23 applies the error compensation signal inputted as a comparison signal of speed control and phase control to rotate the color wheel 1 shown in FIG. 1 synchronously to the rising edge of the vertical synchronous signal. Will drive (M). In other words, the motor driving unit 23 rotates the color wheel 1 shown in FIG. 1 at an angle of approximately 72 ° in synchronism with the rising period of one vertical synchronizing signal. The color wheel 1 is rotated so that B-color light is detected, and at one rotation of the color wheel 1, R, G, and B color light corresponding to five vertical synchronization signals are obtained.

On the other hand, the phase detection signal PG obtained by the electric motor M driving the color wheel 1 is a signal for generating a switching signal pulse by delaying for a predetermined time to compensate for the assembly tolerance for the color wheel 1. Of course, it can be applied.

Therefore, as described above, according to the color wheel of the projection type image display system and the control apparatus thereof, one rotation period of the color wheel is defined so as to correspond to five vertical synchronization signals of the color image signal and the color wheel is designated as the color image. By driving synchronously with the rising edge of the vertical synchronous signal of the signal, it is possible to obtain R, G, and B color light synchronously during the rising period of each vertical synchronous signal of the color image signal by the color wheel of the single plate. The AMA panel corresponding to the unit can be unified, thereby simplifying the color display system of the projection image display system.

Claims (5)

In a color wheel of a projection type image display system which rotates in a vertical synchronization signal period for a color image for projection display of an R, G, B color image signal, one rotation period is five vertical synchronization signal periods in a color image signal. The rotation angle is defined to be 72 ° for each period (1V) of one vertical synchronization signal so as to correspond to the R.G for each vertical synchronization signal period in order to obtain R, G, and B color light of the color image signal. The B color filter areas 2a, 3a, 4a are equally divided, and each of the R, G, B color filter areas 2a, 3a, 4a is irradiated from a light source to form the color image signal. Color wheel of the projection type image display system, characterized in that formed in a size corresponding to the size of the beam shot area (1a). R, G, and B color filter areas 2a, 3a, and 4a are equally divided so that one rotation period corresponds to five vertical synchronization signal periods in the color image signal, and color separation of light irradiated from the light source is performed. Rotational speed detection means for detecting a rotational speed with respect to the electric motor M that is driven to rotate the color wheel 1 that obtains R, G, and B color light; Vertical synchronous signal counting means (11) for counting the rising period of the vertical synchronous signal separated from the color image signal by the vertical synchronous signal separator (10) to generate the reference phase signal; Phase comparison means for detecting a phase difference by comparing a phase of a phase reference signal provided from the vertical synchronous signal counting means (11) with a phase of an electric motor (M) for rotating the color wheel (1); Error detection means (19) for obtaining an error value from the rotational speed detected by said rotational speed detection means and a phase value detected by said phase comparing means; Error compensating means (20) for modulating a pulse width (PWM) to compensate for the error value detected by said error detecting means (19); The electric motor (1) is amplified by a PWM-modulated compensation value by the error compensating means 20 so that the color wheel 1 is rotated by 5 vertical synchronization signals of the color image signal to display R, G, and B colors. A color wheel control apparatus for a projection type image display system, comprising a motor driving means (23) for driving M). 3. The phase comparing unit 12 according to claim 2, wherein the phase comparing unit detects a phase difference by comparing the reference phase signal with the phase signal of the electric motor M and the phase difference detected by the phase comparing unit 12. And a low pass filter (14) for low pass filtering, and a loop filter (15) for filtering the low pass filtered phase difference for loop stabilization. 3. The rotational speed detecting unit according to claim 2, wherein the rotational speed detecting unit detects a frequency signal corresponding to the rotation of the electric motor M driving the color wheel 1 as a voltage signal to obtain a speed signal; And a low pass filter (18) for low pass filtering the speed signal obtained by the rotational speed detection section (17). The error detecting means (19) according to claim 2, wherein the error detecting means (19) adds the phase difference with respect to the phase of the electric motor (M) driving the color wheel (1) and the rotational speed to detect an error value with respect to the phase and the speed. Color wheel control device of a projection type image display system, characterized in that the adder.