JPH0879656A - Head-mounted display device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a head-mounted display device in which the user does not feel annoyance when viewing an image and the deterioration of the liquid crystal layer of the liquid crystal shutter does not easily occur. The clock signal generated by the crystal oscillator circuit 21 is set to a frequency at which flicker is not felt by the counter circuit 22, and the control signal set by the volume 24 and the DC bias setting circuit 26 is stored in the buffer 27 and the signal line 29. Via the non-inverting amplification computing unit 30 and the inverting amplification computing unit 31
Sent to The DC portion of the non-inverting output processed by the non-inverting amplification calculator 30 is removed by the DC bias cut circuit 34a, and the inverting output processed by the inverting amplification calculator 31 is similarly DC bias cut circuit. The direct current portion is removed at 34b, and the application terminal 36 of the liquid crystal shutter 5 is removed.
Or applied to 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external environment confirmation type head-mounted display device used for virtual reality or the like.

[0002]

2. Description of the Related Art FIG. 5 shows a block circuit diagram of a liquid crystal shutter drive circuit of a conventional head-mounted display device.

In FIG. 5, the liquid crystal shutter drive circuit is an NTS.
C decoder 72, video inversion circuit 74, sync separation circuit 7
3, a liquid crystal display control circuit unit 7 including a timing signal generation circuit 75 and a backlight control circuit 76.
9, a flip-flop circuit 81, an amplification operation circuit 84a
And 84b, a liquid crystal shutter control circuit section 85.

Here, in FIG. 5, an NTSC (National Television S) input from a video signal input terminal 71 is input.
A television signal of a ystem committee system, that is, a so-called NTSC signal is sent to the NTSC decoder 72 and the sync separation circuit 73. The NTSC decoder 72 is the NT
The SC signal is decoded and the RGB video signal is sent to the video inverting circuit 74. The video inversion circuit 74 uses RGB
The red signal, the green signal, and the blue signal of the video signal are inverted at the timing of the horizontal synchronizing signal and sent to the liquid crystal panel 77, and the liquid crystal panel 77 displays an image based on this signal. The sync separation circuit 73 extracts the composite sync signal and the vertical sync signal from the NTSC signal, sends the composite sync signal to the timing signal generation circuit 75 and the backlight control circuit 76, and sends the vertical sync signal to the frequency multiplier oscillator 200. . The timing signal generation circuit 75 generates various clocks based on the composite sync signal and sends it to the liquid crystal panel 77. The backlight control circuit 76 also generates a backlight control signal based on the composite sync signal and sends it to the backlight 78. The flip-flop circuit 81 is
Based on a clock that is an integral multiple of the vertical synchronization signal sent from the frequency doubling oscillator 200, the non-inverted output terminal 82 sends the non-inverted output to the amplification operation circuit 84a, and the inverting output terminal 83 sends the inverted output to the amplification operation circuit. Send to 84b.
The shutter drive control signal arithmetically processed by the amplification arithmetic circuit 84a is output to the non-inverted output side terminal 92 of the liquid crystal shutter 91, and the shutter drive control signal arithmetically processed by the amplification arithmetic circuit 84b is inverted output side terminal of the liquid crystal shutter 91. 93 is applied.

Further, according to FIG. 5, the shutter drive control signal is obtained based on the vertical synchronizing signal of the video signal input to the liquid crystal display control circuit section 79 via the video signal input terminal 71. There is. Therefore, the liquid crystal shutter 91 operates according to the input video signal.

[0006]

By the way, since the shutter drive circuit shown in FIG. 5 is provided inside the main body, the weight of the main body becomes large and it is difficult to mount it for a long time.

Further, even when the shutter drive circuit is installed outside the main body, the shutter drive control signal for driving the liquid crystal shutter is not sent from the oscillation circuit, but as shown in FIG. 5, for example. Since it is obtained based on the vertical synchronizing signal of the video signal displayed on the liquid crystal panel 77, the bright bands 101a, 1a, 1
01b and 101c seemed to flow, which was annoying.

Further, when the shutter drive control signal is applied to the liquid crystal shutter 91, two kinds of signals of non-inverted output and inverted output are applied as shown in FIG. In addition, it is possible to apply a voltage twice as high as the power supply voltage (V _cc ), and make the ratio of the low period 111 and the high period 112 of each of the above two types of signals equal. Therefore, the DC component was set to 0. However, in reality, there is a rounded waveform 113, etc., which becomes a DC component and is applied to the liquid crystal.
It led to deterioration of the liquid crystal.

Therefore, the present invention has been made in view of the above-mentioned circumstances, can be worn for a long time, does not cause any trouble when mounting the apparatus body, and deteriorates the liquid crystal of the liquid crystal shutter of the apparatus body. An object of the present invention is to provide a head-mounted display device that is less likely to cause heat.

[0010]

In order to solve the above-mentioned problems, a head-mounted display device according to the present invention is
An image display means for displaying an arbitrary image, for example, a liquid crystal display, a lens for enlarging the image displayed on the image display means, a liquid crystal shutter for adjusting the amount of incident light from the outside, and the liquid crystal shutter. A shutter drive circuit for driving is provided, and the shutter drive circuit sets the drive frequency to a frequency that is out of synchronization with the vertical synchronization frequency of the external display means.

The shutter drive circuit may be separated from the main body.

Further, it is preferable that the shutter drive circuit has a DC cut filter for removing a DC component.

[0013]

According to the head-mounted display device of the present invention, the frequency of the shutter drive control signal for driving the liquid crystal shutter is set to a frequency that is out of synchronization with the vertical synchronizing frequency of another external display means. The flicker becomes inconspicuous even when the above-mentioned device main body is mounted and other display means such as a television or a monitor is viewed.

Further, by providing a shutter drive circuit for generating the shutter drive control signal outside the apparatus body, the weight of the apparatus body can be reduced.

Further, the shutter drive control signal is provided with a DC cut filter for cutting a DC component of the shutter drive control signal before applying the shutter drive control signal to the liquid crystal shutter. Is not directly applied to the liquid crystal shutter.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment to which the head-mounted display device according to the present invention is applied will be described in detail below with reference to the drawings.

FIG. 1 is a view showing the schematic arrangement of an embodiment of a head-mounted display device according to the present invention.

In FIG. 1, the head-mounted display device of this embodiment is roughly divided into a display device main body portion, a circuit box portion 12 and a small VTR portion 13. The display device main body includes liquid crystal displays 1a and 1b, mirrors 2a and 2b, lenses 3a and 3b, a half mirror 4, a liquid crystal shutter 5, a housing 6, a head mounting portion 7, and a liquid crystal shutter of a liquid crystal shutter driving portion described later. It is composed of a drive control unit and a backlight of a liquid crystal display control unit described later. Also, the circuit box part 1
Reference numeral 2 is composed of a volume knob 11, a control unit of the liquid crystal shutter drive unit, which will be described later, and a liquid crystal display control circuit unit of the liquid crystal display control unit. The display device body and the circuit box unit 12 are connected by a transmission line 8, and the circuit box unit 12 and the small VTR unit 13 are connected.
And are connected by a control line 9.

Here, according to FIG. 1, the small VTR unit 13 is provided.
The image sent from the circuit box unit 12 from the LCD is displayed on the liquid crystal displays 1a and 1b. Here, the image displayed on the liquid crystal display 1a is bent by the mirror 2a at an angle of 45 degrees, enlarged by the lens 3a, bent by the half mirror 4 and displayed in the visual range of the user. In addition, the image displayed on the liquid crystal display 1b is the lens 3 after the optical path is bent 45 degrees by the mirror 2b.
The image is enlarged by b, the optical path is bent by the half mirror 4, and the image is displayed within the visual field of the user. That is, the user can view the video as a virtual image. Furthermore, since the half mirror has a function of reflecting the image and transmitting incident light from the outside, that is, outside light, it is possible to view the virtual image while confirming the outside.

FIG. 2 is a view showing the schematic arrangement of the liquid crystal shutter drive section of the head-mounted display device of this embodiment.

In FIG. 2, the liquid crystal shutter drive unit is roughly divided into a control unit 28 installed in the circuit box unit 12 shown in FIG. 1 and a liquid crystal shutter drive control unit 35 installed in the apparatus body. It is divided into The control unit 28 includes a crystal oscillator circuit 21, a counter circuit 22, resistors 23 and 25, a volume 24, a DC bias setting circuit 26, and a buffer 2.
7, the liquid crystal shutter drive control unit 35 includes a DC bias cut circuit 34a and 34 including a non-inverting amplification computing unit 30 and an inverting amplification computing unit 31, a resistor 32a and a capacitor 33a, or a resistor 32b and a capacitor 33b.
b. The control unit 28 and the liquid crystal shutter drive control unit 35 are connected by a signal line 29.

Here, in FIG. 2, the crystal oscillation circuit 21
The clock signal generated in 1 is sent to the counter circuit 22. The counter circuit 22 sets the frequency of the signal of which the counter value indicates the most significant bit in the clock signal is a frequency at which flicker is not felt, for example, a frequency of 82 hertz. The frequency set here is a frequency apart from both the vertical synchronizing frequency of the television and the frequency of the illumination light. The signal set by the counter circuit 22 is
It is sent to the resistors 23 and 25 and the volume 24. The values of the resistors 23 and 25 and the volume 24 are determined by the liquid crystal shutter 5.
Is set to a predetermined value that can effectively control the transmittance of
The control signal in which the DC bias is set by the DC bias setting circuit 26 with respect to the output of the volume 24 is stored in the buffer 27.
Via a signal line 29 to the non-inverting amplification computing unit 30 and the inverting amplification computing unit 31 in the liquid crystal shutter drive control unit 35 in the apparatus body of this embodiment. The non-inverted output signal obtained by the arithmetic processing in the non-inverting amplification arithmetic unit 30 is sent to the DC bias cut circuit 34a, the DC bias portion is removed by the resistor 32a and the capacitor 33a, and the applied terminal 36 of the liquid crystal shutter 5 is supplied. Is applied. Similarly, the inverted output signal obtained by the operation processing in the inverting amplification calculator 31 is sent to the DC bias cut circuit 34b, the DC bias portion is removed by the resistor 32b and the capacitor 33b, and the application terminal 37 of the liquid crystal shutter 5 is applied. Applied to.

Further, according to FIG. 2, by setting the frequency of the signal whose counter value shows the most significant bit among the clock signals generated by the crystal oscillation circuit 21 to, for example, 82 Hertz, this frequency becomes The bright band 101 shown in FIG. 6 is greatly separated from the frequency synchronization of the TV or monitor.
The velocities of a, 101b, and 101c increase and the flicker disappears. The frequency of 82 hertz is
Since it is completely out of synchronization with the frequency of the illumination, flicker caused by the illumination light is also invisible. Further, by removing the DC bias portion of the signal obtained by non-inverting or inverting-amplifying the control signal generated by the control unit 28 before applying it to the liquid crystal shutter 5, deterioration of the liquid crystal can be prevented.

FIG. 3 is a block circuit diagram showing a schematic configuration of a liquid crystal display control unit for controlling the operation of the liquid crystal display in this embodiment.

In FIG. 3, the liquid crystal display control section is roughly divided into a video signal input terminal 41, an NTSC signal decoder 42, a sync separation circuit 43, a video inversion circuit 44, and
It is composed of a liquid crystal display control circuit unit 48 composed of a timing signal generation circuit 45 and a backlight control circuit 46. The video signal input terminal 41 is installed on the side of the small VTR 13 shown in FIG. 1, and the liquid crystal display control circuit section 48 is installed in the circuit box section 12 shown in FIG.

Here, according to FIG. 3, the small VTR unit 13 is provided.
From the NTS input via the video signal input terminal 41
A television signal of the C (National Television System Committee) system, a so-called NTSC signal, is sent to the NTSC signal decoder 4 in the liquid crystal display control circuit unit 48.
2 and the sync separation circuit 43. The NTSC signal sent to the NTSC signal decoder 42 is decoded into RGB signals.
It becomes a video signal and is sent to the video inversion circuit 44, and the video inversion circuit 44 inverts the red (R) signal, the green (G) signal, and the blue (B) signal at the timing of the horizontal synchronizing signal, and the liquid crystal display 1 Sent to. The NTSC signal sent to the sync separation circuit 43 has a color sync portion extracted, and this composite sync signal is sent to the timing signal generation circuit 45 and the backlight control circuit 46. The timing signal generating circuit 45 generates signals having various clock frequencies from the composite sync signal and sends the clock signals to the liquid crystal display 1.
Further, the backlight control circuit 46 generates a backlight control signal from the composite sync signal and sends it to the backlight 47.

In FIG. 3, the liquid crystal display 1 performs screen display based on the R signal, the G signal, the B signal and the signals having various clock frequencies.

FIG. 4 is a view showing the schematic arrangement of the optical system of the head-mounted display device according to this embodiment.

In FIG. 4, the liquid crystal display 1 is installed so that the display screen is parallel to the direction of gravity, and the mirror 2
The optical path of the image projected from the liquid crystal display 1 to 45
The lens 3 is installed at a predetermined position where it is bent, and the optical path in which the lens 3 is bent by the mirror 2 is installed so as to pass through the optical axis. Further, the half mirror 4 is installed so that the angle 55 formed by the reflection layer and the plane parallel to the plane including the tangent line of the lens 3 changes to some extent within the acute angle range. Also,
The rotary shaft 51 is fixed on the half mirror 4, and the rotary shaft 51 is held by a bearing 52 with an appropriate frictional force. Further, a liquid crystal shutter 5 for adjusting the amount of incident light from the outside, so-called outside light, is installed at a predetermined position substantially parallel to the half mirror 4 and capable of rotating the half mirror 4.

Here, according to FIG. 4, an image from a small VTR or the like is displayed on the liquid crystal display 1 and the mirror 2 is displayed.
Is reflected by the lens 3, enlarged by the lens 3, further reflected by the half mirror 4, and reaches the eyeball 53 as a virtual image 54a or 54b. That is, the virtual image 54a is displayed in the field of view of the user.
Alternatively, 54b is displayed. Further, the user changes the angle 55 by moving and rotating the end of the half mirror 4 by hand, and the angle of looking into the virtual image 54a or 54b,
That is, the angle at which the virtual image 54a or 54b is located with respect to the line-of-sight direction can be changed. That is, the arrow 56a
When the half mirror 4 is rotated in the direction indicated by, the virtual image appears to move upward, and when the half mirror 4 is rotated in the direction indicated by the arrow 56b, the virtual image appears to move downward.

In this embodiment, the mirror is arranged so as to bend the optical path of the image displayed on the liquid crystal display by 45 degrees, but the present invention is not limited to this, and other optical systems,
For example, if the image is displayed in the user's visual range through a lens, a half mirror, etc., the optical path of the image may be arranged to be bent at another angle, or the image may be directly transmitted through the lens. That is, it can be omitted if the mirror as described above is not necessary.

In the present embodiment, an example in which the image displayed on the liquid crystal display is obtained from the small VTR device is shown, but the present invention is not limited to this, and a computer having a video output can be connected to this computer. May be displayed on the liquid crystal display.

Further, in the present embodiment, the frequency of the signal for driving the liquid crystal shutter is set to 82 Hz, but the frequency is not limited to this, and the frequency of the illumination light or an external display device, for example, a television. Needless to say, the effect of the present invention can be obtained by setting the frequency away from the frequency of the monitor or the like.

In this embodiment, as an example of the optical system,
An example of a head-mounted display device that rotates a half mirror has been given, but the present invention is not limited to this.
It goes without saying that the effects of the present invention can be obtained even when used in a head-mounted display device having a fixed half mirror.

[0035]

As described above, according to the head-mounted display device of the present invention, an image display means for displaying an arbitrary image, for example, a liquid crystal display, and the image display means are displayed. It has a lens for enlarging the image, a liquid crystal shutter for adjusting the amount of incident light from the outside, and a shutter drive circuit for driving the liquid crystal shutter. Since the frequency is out of synchronization with the vertical synchronizing frequency of the means, the flicker becomes inconspicuous and troublesome even when the apparatus body is mounted and other display means is seen.

Further, since the shutter drive circuit is separated from the apparatus body, the apparatus body can be reduced in weight and can be worn for a long time.

Since the shutter drive circuit has the DC cut filter for removing the DC component, the DC component of the shutter drive control signal is not directly applied to the liquid crystal shutter. Deterioration is less likely to occur. .

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of a head-mounted display device according to the present invention.

FIG. 2 is a block circuit diagram showing a schematic configuration of a liquid crystal shutter drive unit of the head-mounted display device of this embodiment.

FIG. 3 is a block circuit diagram showing a schematic configuration of a liquid crystal display control unit of the head-mounted display device of this embodiment.

FIG. 4 is a diagram showing a schematic configuration of an optical system of the head-mounted display device according to the present embodiment.

FIG. 5 is a block circuit diagram showing a schematic configuration of a liquid crystal shutter drive circuit of a conventional head-mounted display device.

FIG. 6 is a diagram illustrating an operation of a conventional head-mounted display device.

FIG. 7 is a diagram illustrating a voltage applied to a liquid crystal shutter of a conventional head-mounted display device.

[Explanation of symbols]

 1, 1a and 1b Liquid crystal display 3, 3a and 3b Lens 4 Half mirror 5 Liquid crystal shutter 6 Housing 7 Head mounting part 8 Transmission line 9 Control line 11 Volume knob 12 Circuit box part 13 Small VTR part 21 Crystal oscillation circuit 22 Counter Circuit 23 Resistor 24 Volume 25 Resistor 26 DC bias setting circuit 27 Buffer 28 Control part 29 Signal line 30 Non-inverting amplification calculator 31 Inversion amplification calculator 32a, 32b Resistors 33a, 33b Capacitors 34a, 34b DC bias cut circuit 35 Liquid crystal shutter drive Control unit 41 Video signal input terminal 42 NTSC signal decoder 43 Sync separation circuit 44 Video inversion circuit 45 Timing signal generation circuit 46 Backlight control circuit 47 Backlight 48 Liquid crystal display control circuit unit 51 Rotation axis 52 Axis 53 eyeball 54a, 54b virtual image

Claims (4)

[Claims] 1. A head mounted display device for confirming the outside world, comprising image display means for displaying an arbitrary image, a lens for enlarging the image displayed on the image display means, and A liquid crystal shutter that adjusts the amount of incident light, and a shutter drive circuit that drives the liquid crystal shutter. The shutter drive circuit has a drive frequency that is out of synchronization with the vertical synchronization frequency of the external display means. A head-mounted display device comprising: 2. The head-mounted display device according to claim 1, wherein the shutter drive circuit is separated from the main body. 3. The head-mounted display device according to claim 1, wherein the shutter drive circuit has a DC cut filter for removing a DC component. 4. A head mounted display device for confirming the outside world, comprising: an image display means for displaying an arbitrary image; a lens for magnifying the image displayed on the image display means; 2. A head-mounted display device, comprising: a liquid crystal shutter for adjusting the amount of incident light of 1., and a shutter drive circuit that drives the liquid crystal shutter and has a DC cut filter that removes DC components.