JPH1198539A - Space transmission signal transmitter for liquid crystal shutter eyeglass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the space transmission signal transmitter for a liquid crystal shutter eyeglasses by which jitter can be reduced. SOLUTION: An infrared ray LED light emitting section (not shown in Fig. is driven by an LED drive pulse. An AND circuit 28 generates the LED drive pulse by modulating a clock with a 1st frequency (56 kHz) by a signal (gate signal) denoting a right eye video or a left video. An edge detection means 23 receives a clock with a 2nd frequency (1.8 MHz) higher than the 1st frequency (56 kHz) and detects an edge of an LR polarity switching signal by the clock. A 9-bit counter 26 counts the clock with the 2nd frequency (1.8 MHz), based on the detected edge, and generates the gate signal, based on the clock count.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In a liquid crystal shutter glasses worn by an observer, a right-eye image and a left-eye image are alternately displayed on a screen at a constant period. There is known a three-dimensional image display system in which transmission and non-transmission are alternately performed between a liquid crystal for use and a left-eye liquid crystal, and an observer performs stereoscopic viewing. The present invention relates to a spatial transmission signal transmission device for liquid crystal shutter glasses that transmits a spatial transmission signal to be supplied to liquid crystal shutter glasses based on a signal indicating switching between a left-eye video and a right-eye video alternately displayed on a screen. About.

[0002]

2. Description of the Related Art Right-eye image (R) on a stereoscopic image display device side
There is a technique using an infrared signal to notify the liquid crystal shutter glasses of the switching between the left and right eye images (L). As a specific configuration, a configuration shown in FIG. 12 can be considered. In this configuration, a clock of 455 to 500 KHz is frequency-divided by a frequency divider 501 to about 30 to 57 KHz, and this is used as a carrier wave. The gate signal generation circuit 502 receives the clock as the carrier wave, and uses the clock to indicate a switch between a left-eye image and a right-eye image alternately displayed on a screen (hereinafter, referred to as an LR polarity switching signal). ) Is detected, and a signal (hereinafter, referred to as a gate signal) indicating the distinction between the right-eye image and the left-eye image is generated based on the edge. Then, the AND circuit 503 generates an LED drive pulse by taking the logical product of the clock as the carrier and the gate signal. This LED driving pulse is given to an LED light emitting unit (not shown).
The light emitting section emits light (blinks) according to the drive pulse.

[0003]

However, in the above configuration, as shown in FIG. 13, the deviation (jitter t) between the edge of the LR polarity switching signal and the rise of the gate signal is the maximum at the carrier wave. A certain clock (30 ~
This is equivalent to one clock (57 KHz) (about 20 μs), and the jitter is relatively large. When the signal having this jitter is reproduced (decoded) on the liquid crystal shutter glasses side, the jitter based on the clock on the liquid crystal shutter glasses side is further added, so that the total jitter width becomes larger and the screen flickers. It comes as a feeling. Also, if the width of the jitter is large, various other problems occur.

[0004] In view of the above circumstances, an object of the present invention is to provide a spatial transmission signal transmitting apparatus for liquid crystal shutter glasses that can reduce jitter.

[0005]

In order to solve the above-mentioned problems, a spatial transmission signal transmitting apparatus for liquid crystal shutter glasses according to the present invention has a left-eye image and a right-eye image alternately displayed on a screen. A spatial transmission signal generating means driven by a driving pulse; and a clock having a first frequency, the spatial transmission signal transmitting device for transmitting the spatial transmission signal to be supplied to the liquid crystal shutter glasses based on the signal indicating the switching of A drive pulse generating means for generating the drive pulse by modulating with a signal indicating the distinction between a right-eye image and a left-eye image, and a clock having a second frequency higher than the first frequency are input. An edge detecting means for detecting an edge of the signal indicating the switching; a means for counting the clock of the second frequency based on the detected edge; Based on the lock count value, characterized in that a means for generating a signal indicative of another of said right-eye image and the left eye image.

According to the above arrangement, the signal indicating the distinction between the right-eye image and the left-eye image is generated with reference to a clock having a second frequency higher than the first frequency. The jitter is smaller than a configuration (corresponding to the configuration in FIG. 12) in which a signal indicating the difference between the left and right images is generated based on the clock of the first frequency.

In the above arrangement, means for converting the clock of the second frequency to a clock of the first frequency may be provided, and the entire circuit including this means may be integrated.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an infrared LED driving pulse generator 101 in an infrared signal transmitting apparatus according to an embodiment of the present invention.
FIG. FIG. 2 is a timing chart showing various signals in the infrared LED drive pulse generator 101. FIG. 3 shows an infrared LED drive pulse generator 10.
1 is a circuit diagram showing a configuration in which an infrared LED 33 is driven by an infrared LED drive pulse from the system LSI 200 using a system LSI 200 including the LED 1.

In FIG. 1, a 4-bit counter 21
A 1.8 MHz clock from a clock generator (not shown) is input to the clock (CLK) terminal, and every time 16 pulses of this clock are input, one pulse is output from the carry-out (C0) terminal. Output. That is, the 1.8 MHz clock is divided by 16. Further, when a High signal is input to a reset (RST) input unit, the reset is performed.

The divide-by-2 circuit 21 has its enable (E
N) The carry-out (C0) signal from the 4-bit counter 21 is input to the terminal unit. Clock (CLK)
The 1.8 MHz clock is supplied to the terminal section. The data (D) terminal portion is supplied with a signal from the Q bar output terminal. Each time a pulse of the carry-out (C0) signal is input, the divide-by-2 circuit 21 outputs a Hi signal at the Q output terminal.
The gh signal and the Low signal are output alternately. This output signal becomes 56 KHz and is used as a carrier (sub-carrier). Further, when a High signal is input to a reset (RST) input unit, the reset is performed.

The edge detector 23 outputs the clock (CL
K) The 1.8 MHz clock is input to the terminal section. Then, an LR polarity switching signal (a signal indicating switching between left and right eye images) corresponding to the L and R video signals is input. As shown in FIG. 2A, the LR polarity switching signal is a signal that alternately forms High and Low at regular intervals, and for example, indicates that High is in the right-eye image display state. Low indicates that the left eye image is displayed. As shown in FIG. 2 (i), the edge detecting unit 23 is 1.8 when the LR polarity switching signal is High.
The reset signal (High) is output when the first pulse of the MHz clock is input. This reset signal is supplied to the 4-bit counter 21, the frequency-dividing circuit 21, and a 9-bit counter 26 described later.

The 9-bit counter 26 has, at its enable (EN) terminal section, a logical product of a value obtained by inverting the carry-out (C0) signal by the inverter 25 and the 16-divided value by the AND circuit 24. input. The clock (C
LK) The 1.8 MHz clock is input to the terminal section. Then, a count value (9-bit signal) corresponding to the divide-by-16 value is output from the Q terminal. More specifically, as shown in (e), (f), (g), and (i) of FIG. 2, after the reset by the edge detection, a period from when the first High in the divide-by-16 output is output is output. The period is counted as the count value “0”, the period until the next High is output is the count value “1”, and the period until the next High is output is the count value “2”. When the count value reaches 511, the counting is stopped. Further, when a High signal is input to a reset (RST) input unit, the reset is performed. In addition,
The reason why the 9-bit count is used is that the generation of a gate signal to be described later is completed before 512 counts, and the count more than that is because the circuit scale is increased, and there is no advantage. is there.

The gate signal generation circuit 27 generates a signal based on the count value output from the 9-bit counter 26.
A gate signal as shown in FIG. 2B is generated. The gate signal is a signal composed of, for example, a relatively long High period, a short High period, and a Low period therebetween, as shown in FIG. 2B, and the length of the Low period is L (left eye). Image display state) and R (right-eye image display state). The High period and the Low period are defined by the count value. Note that the clock signal input to the gate signal generation circuit 27 is the Hig in the gate signal.
It is not used for setting the h period or the like, but for timing control in an internal flip-flop or the like.

The drive pulse generation AND circuit 28 receives the carrier (56 KHz) and the gate signal from the gate signal generation circuit 27, and calculates the logical product of the signals to obtain the infrared signal L.
Generate an ED drive pulse. That is, the carrier is modulated by the gate signal.

Here, the timing deviation (jitter range) of the generation of the gate signal generated based on the edge of the LR polarity switching signal depends on the deviation width of the edge detection in the edge detection circuit 23 with respect to the LR polarity switching signal. This shift width is, as shown in FIG.
This corresponds to one clock of 1.8 MHz, and the jitter range is extremely small. In addition, when observing the image of the large screen or the image of the image display device placed by a plurality of persons by a plurality of people, it may be possible to install a plurality of infrared signal transmitting devices. In addition, mutual interference easily occurs in infrared signals from a plurality of infrared signal transmitting devices. Since the jitter in the above configuration is extremely small, such interference can be reduced.

As shown in the circuit diagram of FIG. 3, the infrared LED driving pulse generated by the driving pulse generating and
The light is supplied to a light emitting unit 30 composed of 3 or the like. The infrared LED
33 emits light in response to the infrared LED drive pulse and outputs an infrared signal.

Next, the driving device of the liquid crystal shutter glasses will be described. FIG. 4 is a block diagram showing a driving device of the liquid crystal shutter glasses. The portion surrounded by the dotted frame in this figure is integrated. Hereinafter, the dotted frame portion is referred to as an integrated circuit portion 102. FIG. 5 shows a system LSI 200 including the integrated circuit unit 102.
FIG. 6 is a block diagram in the case of using.

The infrared receiving module 1 includes the light emitting section 30
Receive the infrared signal output from. A jack 2 for directly receiving an LR discrimination signal (corresponding to an LR polarity switching signal) is provided to enable selection between wireless (when an infrared signal is used) and wired.

The input signal type automatic discriminating section 3 judges the type of the input signal. For example, the input signal based on the infrared signal is a simple signal of repetition of H and L, a signal coded corresponding to L and R, or a signal obtained by further adding a carrier wave to the coded signal. Judge whether or not.

The field frequency detection / LR discrimination unit 6
Based on the received infrared signal or LR determination signal, a process of detecting a field frequency and determining whether the signal is an L signal or an R signal is performed. In this discrimination, in the case of the infrared signal, a signal corresponding to the above-described gate signal is obtained by the demodulation process, so that the relatively long High signal is obtained.
The length of the Low period between the short period and the short High period is L
(Left-eye image display state) and R (right-eye image display state) can be distinguished. In a wired connection, LR discrimination can be performed immediately from the LR discrimination signal. The field frequency is represented by the number of clocks (count) counted during the LR signal period (High / Low switching period).

The operation field frequency determination unit 7 performs a process of checking the frequency (timing) in the alternate shutter operation of the liquid crystal 13 for the left eye and the liquid crystal 14 for the right eye, and a process of determining and holding the frequency. That is, the Hig of the previous LR signal
By comparing the number of clocks (the old field frequency) counted during the h period or the Low period with the number of clocks (the new field frequency) counted during the Low period or the High period of the current LR signal, frequency fluctuation and stabilization can be achieved. Check. The determination is made when the stable state continues, and when the unstable state is reached, the shutter operation is continued (self-propelled) at the held timing. The purpose is that, even when the reception of the infrared signal is interrupted for some reason, the left-eye liquid crystal 13 and the right-eye liquid crystal 1 are kept at the field frequency held for a while.
4 is to maintain the alternate shutter operation. An outline of such processing is shown by state 3, state 4, and state 5 in the state transition diagram of FIG. The specific processing in each state will be described later in detail with reference to the flowcharts in FIGS.

The liquid crystal drive pulse generator 8 determines the generation of three types of voltages (V _LCD : liquid crystal non-transmission, 0 volt: liquid crystal transmission, -V _LCD : liquid crystal non-transmission) by the analog switches 11 and 12. The analog switch 1 is controlled by the control performed at the field frequency and the timing adjustment signal.
Control for adjusting the timing of 0 volt application (liquid crystal transmission) by 1 and 12 and control of LR polarity switching are performed.

[Control] The analog switch 11,
Reference numeral 12 denotes a voltage (V ₁ ) from the power control unit 4 and a DC / D
Receiving the supply of the voltage (−V ₂ ) from the C converter 10,
V _LCD (= V ₁ + V ₂ ) (closed: non-transmissive state), 0 volt (open: transmissive state), −V _LCD (= − (V ₁ + V ₂ )) (closed: 0 volt (open: transparent state), V
_The potential difference is supplied in the order of _LCD (closed: non-transmissive state). Which one of the three types of potential differences is to be generated can be determined by a 2-bit control signal, and this control signal may be given to the analog switches 11 and 12. The liquid crystal drive pulse generator 8 has a 3-bit output terminal, one of which is common, and the other two are mutually inverted signals.
Are controlled to give a 2-bit control signal to each of them. Which liquid crystal is to be opened and the other liquid crystal is to be closed can be determined by the LR discrimination signal from the field frequency detection / LR discrimination unit 6. The timing at which the 2-bit control signal is applied is determined by the clock count, which is the field frequency determined by the operation field frequency determination unit 7. That is, clock counting is started from the time when the field frequency is determined (see the pulse counter 8b in FIG. 6), and when the clock count in this count matches the clock count, which is the field frequency in principle, The pulse generator 8b (see FIG. 6) generates the 2-bit control signal.

[Control] The period t ₁ in FIG.
This is a control for adjusting. That is, the analog switch 1
The control of timing of the 2-bit control signal to be given to 1 and 12 is performed not by the timing of the determined field frequency but by t ₁ based on the timing adjustment signal. Specifically, the period t ₂ in FIG.
, The open timing of each of the liquid crystals 13 and 14 is advanced by t ₁ while supporting the vertical synchronization by defining the above-described field frequency.
At the end of the vertical blanking, the contrast ratio is set to substantially zero. As a result, it is possible to solve the problem that the upper part of the screen of the image display device becomes dark and visible. Since the timing adjustment signal is 4 bits in this embodiment,
Such control can be performed by adjusting in 16 steps. Also, how much to speed up depends on the open response characteristics of the liquid crystal used.

[Control] Depending on the stereoscopic image display device, the signal representing L and the signal representing R may be reversed. This is a control for reversing the recognition of R and the recognition of R.

The power supply control unit 4 receives power from a power supply unit outside the integrated circuit unit 102 and turns on a power switch.
Then, while supplying power to each circuit in the integrated circuit unit 102, the external DC / DC converter 10
And so on. The clock control circuit 5 receives 300 KH from a clock generator (not shown).
A predetermined clock is supplied to each circuit in the integrated circuit unit 102 by controlling the clock of z. The clock control circuit 5
May include an RC oscillator (RC-oscillator) and generate a clock by itself (see FIG. 6). The timer 9 starts counting the timer when the operation field frequency determination unit 7 enters the field frequency indefinite state. When this state continues for approximately two minutes, the timer 9 issues a power stop command to the power control unit 4. It is supposed to emit.

FIG. 6 is an explanatory diagram showing an outline of the internal configuration of the system LSI 200, the arrangement of pins, and the like.
This system LSI 200 is formed by forming the infrared LED drive pulse generator 101 and the integrated circuit unit 102 on one semiconductor substrate. Therefore, the system LSI 200 can be used to configure an infrared signal transmitting device and also to configure a driving device for liquid crystal shutter glasses. Therefore, mass production is possible as an LSI that can be shared by the stereoscopic video display device and the liquid crystal shutter, and cost can be reduced.

FIG. 8 is a state transition diagram for explaining the transition of the operation state of the driving device for the liquid crystal shutter glasses. Specific processing contents of states 3, 4, and 5 in this state transition diagram,
That is, the processing contents in the operation field frequency determination unit 7 will be described with reference to FIGS. 9 shows processing in the field frequency undefined state (state 3), FIG. 10 shows processing in the field frequency determined state (state 4), and FIG. 11 shows processing in the field frequency maintaining state (state 5). , Respectively.

In FIG. 9, first, a field frequency is detected, and the detected field frequency (clock count number) is set to fnow (step 1). Next, a field frequency check process is performed (step 2).
That is, it is determined whether or not the field frequency fnow detected this time is within a predetermined range (−a to a) based on the field frequency fold detected last time. If not, the check counter (chkcnt) is set to 0
(Clear) and the field frequency fno detected this time
The process returns to step 1 with w as fold. On the other hand, if it is within the range, the check counter (chkcnt) is incremented (step 3). Then, the counter value of the check counter (chkcnt) is determined (step 4). If the counter value becomes 16, it is determined that the frequency has become stable and the field frequency fnow detected this time is determined.
As ffix and fold (step 5),
The processing shifts to the processing in the state where the field frequency is determined.
This field frequency uncertain state (step 3)
In, the pulse counter 8b (see FIG. 6) of the liquid crystal drive pulse generator 8 stops counting. That is, the shutter operation is stopped in the liquid crystal shutter glasses (the shutter operation has not yet started if it is a transition from the state 2).

In FIG. 10, first, a field frequency is detected, and the detected field frequency (clock count number) is set to fnow (step 11). Next, the field frequency fnow detected this time is set to a predetermined range (−a) based on the determined field frequency ffix.
(A) is determined (step 12).
If the result of this check is YES, a new ffix is generated by slightly reflecting the current field frequency fnow (step 14), and the process returns to step 11. on the other hand,
If the determination is NO, the field frequency fnow detected this time is set to fold (step 13), and the state shifts to the field frequency maintaining state.

When the process proceeds to step 14, a reset signal is output to the pulse counter 8b of the liquid crystal drive pulse generator 8, so that the determination in step 15 is YES and the counter value is cleared. Go (step 18) and proceed to step 15. Step 1
When NO is determined in step 5, the counter value is ffix + a
It is determined whether or not the value is larger (step 16). If it is larger, the counter value is cleared (step 1).
9), the process proceeds to the field frequency maintaining state. If it is determined in step 16 that the value is smaller, the counter value is incremented, and step 1 is performed.
Go to 5.

The meaning of the above processing in the pulse counter 8b of the liquid crystal drive pulse generator 8 will be briefly described. When the liquid crystal drive pulse generator 8 counts the clocks corresponding to ffix, the liquid crystal shutter switching operation is performed. However, since the next ffix is not determined in step 14 (infrared signal) Also occurs when the count value exceeds ffix + a without resetting the count operation of the pulse counter 8b, and the shutter operation of the liquid crystal using the ffix is continued (self-propelled). ), The processing shifts to the processing in the state of maintaining the field frequency.

In FIG. 11, first, a field frequency is detected, and the detected field frequency (count value) is set to fnow (step 21). If the state where the infrared signal is interrupted continues, the field frequency cannot be detected during that time, and when it is detected, the field frequency (clock count number) is significantly different from the previous value. Next, a first check of the field frequency is performed in the same manner as in step 12 of FIG. 10 (step 22). If the result of this check is YES, a new ffix is generated by slightly reflecting the current field frequency fnow (step 2).
7) The processing shifts to the processing in the state where the field frequency is determined. On the other hand, if the determination is NO, step 2 in FIG.
The second check processing of the field frequency is performed by the same method as that described above (step 23). If the result of this check is NO, the counter value of the check counter (chkcnt) is cleared (step 28), and the field frequency fnow detected this time is set to fold, and step 21 is executed.
Proceed to.

If YES in step 23,
The counter value of the check counter (chkcnt) is incremented (step 24). Then, the counter value of the check counter (chkcnt) is determined (step 25). If the counter value becomes 16, it is determined that the frequency has become stable and the field frequency fnow detected this time is determined.
Are set as ffix and fold, and the reset counter (rscnt) is cleared (step 26).
The processing shifts to the processing in the state where the field frequency is determined.
If it is determined in step 25 that the counter value is not 16, the process proceeds to step 29. The reset counter (rscnt) determines how long the liquid crystal shutter operation continues (self-runs).

In the field frequency maintaining state, the pulse counter 8b of the liquid crystal drive pulse generator 8
The counting operation is proceeding (step 30), and the counter value is ffix (this ffix is determined in step 13,
14 (that is, the one set in step S14), that is, whether the liquid crystal shutter switching timing has come (step 31). In this step 31, YE
If S, the counter value of the pulse counter 8b is reset to determine the arrival of the next shutter timing (step 32). Then, the reset counter (r
scnt) is incremented (step 33). As described above, the reset counter (rscnt) determines the continuation time (self-running) of the liquid crystal shutter operation, and determines whether or not this time exceeds a maximum allowable value (MAX: corresponding to about 10 seconds). (Step 34), and when it exceeds, the state transits to a state where the field frequency is indeterminate,
The shutter operation of the liquid crystal shutter glasses is stopped. Unless it exceeds, the shutter operation of the liquid crystal is continued (self-propelled). If the field frequency is stabilized during self-running, the state transits to a state where the field frequency is determined.

[0037]

As described above, according to the present invention, it is possible to reduce the jitter in the signal indicating the distinction between the right-eye image and the left-eye image, and to eliminate various problems caused when the jitter is large. It has the effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an infrared LED drive pulse generator of an infrared signal transmitting apparatus according to an embodiment of the present invention.

FIG. 2 is a timing chart showing various signals in an infrared LED drive pulse generation section in a dotted frame portion of FIG. 1;

FIG. 3 is a circuit diagram of an infrared signal transmission system using a system LSI configured to include an infrared LED drive pulse generator in a dotted frame portion of FIG. 1;

FIG. 4 is a block diagram showing a driving device for liquid crystal shutter glasses.

FIG. 5 is a block diagram in a case where a system LSI including a dotted frame portion in FIG. 4 is used;

6 is an explanatory diagram showing a system LSI including the circuit part of FIG. 1 and the dotted frame part of FIG. 4;

FIG. 7 is a timing chart showing the timing of applying 0 volt (open) to the liquid crystal shutter glasses.

FIG. 8 is a state transition diagram in the driving device for liquid crystal shutter glasses according to the embodiment of the present invention.

FIG. 9 is a flowchart showing control contents in a state where the field frequency is indeterminate according to the embodiment of the present invention.

FIG. 10 is a flowchart showing control contents in a state where the field frequency is determined according to the embodiment of the present invention.

FIG. 11 is a flowchart showing control contents in a state of maintaining a field frequency according to the embodiment of the present invention.

FIG. 12 is a block diagram showing a spatial transmission signal transmitting apparatus for liquid crystal shutter glasses having a configuration in which a jitter range becomes relatively large.

FIG. 13 is an explanatory diagram showing a jitter range in the configuration of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Infrared light receiving module 3 Input signal type automatic discrimination part 4 Power supply control part 5 Clock control part 6 Field frequency detection / LR discrimination part 7 Operating field frequency decision part 8 Liquid crystal drive pulse generation part 9 Timer 10 DC / DC converter 11,12 Analog switch 13 14 Liquid crystal 101 Signal control unit of infrared signal transmitting device 102 Integrated circuit unit 200 System LSI 300 Liquid crystal shutter glasses driving device

Claims (2)

[Claims] 1. A spatial transmission signal for liquid crystal shutter glasses for transmitting a spatial transmission signal to be supplied to liquid crystal shutter glasses based on a signal indicating switching between a left-eye video and a right-eye video alternately displayed on a screen. In the apparatus, a spatial transmission signal generating means driven by a driving pulse, and a driving pulse generating means for generating the driving pulse by modulating a clock of a first frequency with a signal indicating a distinction between a right-eye image and a left-eye image And an edge detecting means for inputting a clock having a second frequency higher than the first frequency, and detecting an edge of the signal indicating the switching with the clock; and detecting the edge of the second frequency with reference to the detected edge. Means for counting a clock, and means for generating a signal indicating the distinction between the right-eye image and the left-eye image based on the clock count value. Space transmission signal transmitting device for a liquid crystal shutter glasses according to symptoms. 2. The configuration according to claim 1, further comprising means for converting the clock of the second frequency into a clock of the first frequency, wherein the entire circuit including this means is integrated. Spatial transmission signal transmission device for liquid crystal shutter glasses.