JPH0879187A - Method and device for optical space transmission - Google Patents

Abstract

PURPOSE: To provide a method and device for optical space transmission which secure the coverage distance and reduces the power consumption. CONSTITUTION: A video camera recorder 1 is provided with a video camera 2 and a stereo microphone 6. An LED driver 10 emits a signal including a video signal and an audio signal toward a remote controller from infrared LEDs 25, 26, and 27. A control signal is received from the remote controller through a PIN photo diode 28, and a level detector 38 lights all of three infrared LEDs 25, 26, and 27 to extend the coverage distance of the remote controller if the level of the received control signal is low, but the level detector 38 lights only one infrared LED 26 to reduce the power consumption if this level is high. It is discriminated by a power source discriminator 24 whether the connected power source is an AC adapter power source or a battery; and if it is a battery, only one infrared LED 26 is lit to reduce the power consumption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical space transmission device and an optical space transmission method.

[0002]

2. Description of the Related Art Conventionally, there is a video camera recorder in which electric signals of video and audio are converted into optical signals for spatial transmission, and conversely, the video camera recorder receives a control signal.

For example, as a system for wirelessly transmitting an audio video signal of a video camera recorder system to a television (TV), a system using infrared light has been announced ("spatial transmission system of audio video signal"). Technique US92-83, EA92-9
5).

FIG. 10 is a block diagram showing the configuration of a conventional wireless video camera system. In the figure, 1
a is a video camera recorder, 2a is a video camera, 3a
Is a recorder circuit, 4a is a viewfinder (hereinafter, E
VF), 5a is a video FM modulator, 6a is a stereo microphone, 7a is a left sound FM modulator, 8a is a right sound FM modulator, 9
a is an adder, 10a is an LED driver, 11a is an infrared LED, 12a is a stereo TV monitor, and 13a is a PIN.
The photodiode, 14a is a high-pass filter (hereinafter,
HPF), 15a is a video FM demodulator, 16a is a monitor, 17a is a left sound bandpass filter (hereinafter, BP).
F), 18a is a left sound FM demodulator, 19a is a left sound speaker, 20a is a right sound BPF, 21a is a right sound FM demodulator, 2
2a is a right sound speaker, 39a is a camera signal processing circuit, 4
Reference numeral 0a is an audio signal processing circuit.

An electric signal of an image taken by the video camera 2 is converted into a video signal by the camera signal processing circuit 39a and sent to the recorder circuit 3a for recording. Further, this electric signal is simultaneously projected on the EVF 4a, modulated by the video FM modulator 5a into the FM wave of the carrier 11 MHz, and sent to the adder 9a.

On the other hand, when the voice is converted into an electric signal by the stereo microphone 6a, the audio signal processing circuit 40a performs processing such as directivity and automatic gain control (AGC) and the right and left FM modulators 7a and 8a, respectively. Carrier 1.3M
It is modulated into an audio signal at Hz and 1.7 MHz. In the adder 9a, the frequencies of the left and right audio signals and the video signal are multiplexed, and the multiplexed signal is current-amplified by the LED driver 10a. The infrared LED 11a converts the light into infrared light and outputs the infrared light.

At this time, the infrared LED 11a is provided with a lens in order to extend the reaching distance, the directional angle is narrowed, and the PIN photodiode 13a for light reception is irradiated most strongly with the video camera recorder 1a and the stereo TV. A monitor 12a is arranged.

The stereo TV monitor 12a converts the signal received by the PIN photodiode 13a into an electric signal and three filters HPF14a, BPF17a, BPF.
20a. The HPF 14a removes the low frequency component of the audio signal band and sends it to the video FM demodulator 15a. The video signal sent by the video FM demodulator 15a is demodulated and displayed on the monitor 16a. Left sound BPF
In 17a, the audio signal is extracted from the band of the left sound modulated at 1.3 MHz. The left audio signal is demodulated by the left sound FM demodulator 18a and output by the left sound speaker 19a. Similarly, right sound BPF 20a and right sound FM demodulator 21a
The right audio signal is output by the right sound speaker 22.

[0009]

However, in the above-mentioned conventional example, there is no problem in the case where the light receiving device is fixed and the distance is constant, but when applied to the light receiving device in which the liquid crystal monitor is attached to the wireless remote controller. Therefore, in order to extend the reach and widen the range according to the moving light receiving device, a large amount of transmission power is always required, but sufficient power is supplied from the battery. In some cases, we could not supply it.

Therefore, it is an object of the present invention to provide an optical space transmission device and an optical space transmission method in which power consumption is suppressed while securing a reachable distance.

[0011]

In order to achieve the above object, an optical space transmission apparatus according to claim 1 of the present invention is an optical space transmission apparatus for performing spatial transmission using a plurality of light emitting elements and light receiving elements. A driving means for driving the light emitting element, a level discriminating means for discriminating the level of the received control signal, and a driving number changing means for changing the driving number of the light emitting element based on the discriminated information. .

According to a second aspect of the present invention, there is provided an optical space transmission device, wherein in a space optical transmission device for performing spatial transmission using a plurality of light emitting elements and light receiving elements, the driving means for driving the light emitting elements and the type of power supply are determined. The power source determining means and the drive number changing means for changing the drive number of the light emitting element based on the determined information.

According to a third aspect of the present invention, there is provided an optical space transmission device, which is a space optical transmission device for performing spatial transmission using a plurality of light emitting elements and light receiving elements, and a driving means for driving the light emitting elements and a power source for discriminating a kind of power source. Discriminating means, level discriminating means for discriminating the level of the received control signal, and drive number changing means for changing the drive number of the light emitting element based on the information of the discriminated control signal level and the type of power source. Equipped with.

According to a fourth aspect of the present invention, there is provided an optical space transmission device, wherein in a space optical transmission device for performing spatial transmission using a plurality of light emitting elements and light receiving elements, a driving means for driving the light emitting elements and a level of a received control signal. And a drive current changing means for changing the drive current of the light emitting element based on the determined information.

An optical space transmission apparatus according to a fifth aspect of the invention is an optical space transmission apparatus that performs spatial transmission using a plurality of light emitting elements and light receiving elements, and determines the driving means for driving the light emitting elements and the type of power supply. The power source determining means and the drive current changing means for changing the drive current of the light emitting element based on the determined information.

According to a sixth aspect of the present invention, there is provided an optical space transmission apparatus, wherein in a space optical transmission apparatus for performing spatial transmission using a plurality of light emitting elements and light receiving elements, a driving means for driving the light emitting elements and a kind of a power source are discriminated. Power source discriminating means, level discriminating means for discriminating the level of the received control signal, and drive current changing means for altering the drive current of the light emitting element based on the discriminated control signal level and information on the type of power source. With.

An optical space transmission apparatus according to a seventh aspect of the present invention performs the spatial transmission of audio signals and video signals in the optical space transmission apparatus according to any of the first to sixth aspects.

An optical space transmission method according to an eighth aspect of the present invention is an optical space transmission method in which space transmission is performed using a plurality of light emitting elements and light receiving elements, the level of a received control signal is discriminated, and the discriminated information is obtained. Based on this, the number of driven light emitting elements to be driven is changed.

[0019]

In the optical space transmission device according to the first aspect of the present invention,
When performing spatial transmission using a plurality of light emitting elements and light receiving elements, the driving means drives the light emitting elements, the level determining means determines the level of the received control signal, and based on the determined information, The drive number changing means changes the drive number of the light emitting element.

In the space optical transmission apparatus according to the second aspect, when performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting element is driven by the driving means and the type of the power source is discriminated by the power source discriminating means. Then, based on the determined information, the drive number changing means changes the drive number of the light emitting element.

In the space optical transmission apparatus according to the third aspect of the present invention, when performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting element is driven by the driving means and the type of the power source is discriminated by the power source discriminating means. The level discriminating unit discriminates the level of the received control signal, and the drive number changing unit changes the drive number of the light emitting element based on the discriminated control signal level and information on the type of the power source.

In the space optical transmission apparatus according to a fourth aspect of the present invention, when performing space transmission using a plurality of light emitting elements and light receiving elements, the driving means drives the light emitting elements and the level determination means receives the control signal received. The level is determined, and the drive current of the light emitting element is changed by the drive current changing means based on the determined information.

In the space optical transmission apparatus according to the fifth aspect, when performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting element is driven by the driving means and the type of the power source is discriminated by the power source discriminating means. Then, the drive current changing means changes the drive current of the light emitting element based on the determined information.

In the space optical transmission apparatus according to the sixth aspect, when performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting element is driven by the driving means and the type of the power source is discriminated by the power source discriminating means. Then, the level of the received control signal is determined by the level determining means, and the drive current of the light emitting element is changed by the drive current changing means based on the determined level of the control signal and the information of the type of the power source.

[0025]

EXAMPLES Next, examples of the optical free space transmission apparatus of the present invention will be described. The optical space transmission device of this embodiment is applied to a wireless video camera system.

[First Embodiment] FIG. 1 is a block diagram showing the arrangement of a wireless video camera system according to the first embodiment. In the figure, 1 is a video camera recorder, 2 is a video camera, 3 is a recorder circuit, 4 is an EVF, 5 is a video FM modulator, 6 is a stereo microphone, 7 is a left sound FM modulator, and 8 is a right sound FM modulator. , 9 is an adder, 10 is an LED driver, 13 is a PIN photodiode, and 14 is HP
F and 15 are video FM demodulators, 17 is left sound BPF, 18
Left sound FM demodulator, 20 is right sound BPF, 21 is right sound FM demodulator, 23 is sensor, 24 is power supply discriminator, 25, 26,
27 is an infrared LED, 28 is a PIN photodiode,
29 is a camera control circuit, 30 is a liquid crystal (LCD) driver, 31 is an LCD monitor, 32 is a headphone terminal,
33 is a remote control button, 34 is a control code generator, and 35
Is an infrared LED, 36 is a remote controller with an LCD monitor, 3
Reference numeral 7 is a power source composed of an AC adapter or a battery, 38 is a level detector, 39 is a camera signal processing circuit, and 40 is an audio signal processing circuit.

FIG. 2 is a front view showing the appearance of the remote controller 36. An LCD monitor 31 and various remote control buttons 33 are arranged on the front surface of the main body of the remote control 36. An infrared LED 35 and a PIN photodiode 13 are arranged on the upper surface of the main body, and a headphone terminal 32 is provided on the side surface.

An electric signal of an image taken by the video camera 2 is converted into a video signal by the camera signal processing circuit 39 and then sent to the recorder circuit 3 for recording. Further, when this electric signal is sent to the EVF 4 at the same time, it is displayed as an image. In addition, this electrical signal is a video FM
The modulator 5 modulates the carrier into an FM wave of 11 MHz and sends it as a video signal to the adder 9.

On the other hand, the audio electric signal converted by the stereo microphone 6 is processed by the audio signal processing circuit 40 such as directivity and automatic gain control (AGC). This electric signal is modulated by the FM modulators 7 and 8 on the left and right sides into FM waves having a carrier of 1.3 MHz and 1.7 MHz, and sent to the adder 9 as an audio signal.

The adder 9 multiplexes the frequencies of the left and right audio signals and the video signal, and sends the multiplexed signal to the LED driver 10. The LED driver 10 causes three infrared LEDs 25, 26, 27 to emit light, and outputs a signal multiplexed in space. That is,
In this embodiment, a video signal and an audio signal are output from the front of the video camera recorder 1. The processing of the LED driver 10 will be described later.

On the other hand, on the remote controller 36 side, the user holds the remote controller 36 and moves to the front of the video camera recorder 1 to receive infrared rays from the infrared LEDs 25, 26, 27. The signal received by the PIN photodiode 13 is converted into an electrical signal and the three filters HPF1
4, sent to BPF17, BPF20. The HPF 14 sends the signal from which the low frequency component of the audio signal band is removed to the video FM demodulator 15. When the video signal sent to the video FM demodulator 15 is demodulated, an image is displayed on the LCD monitor 31 by the LCD driver 30.

In the left sound BPF17, 1.3 MHz
The audio signal in the left sound band modulated by is extracted.
The left audio FM demodulator 18 demodulates the left audio signal and outputs it to the headphone terminal 32. Similarly, the right sound BPF2
0 and the right sound FM demodulator 21 outputs the right audio signal to the headphone terminal 32.

The user checks the image displayed on the video camera recorder 1 on the LCD monitor 31 and connects the headphones to the headphone terminal 32 to check the sound picked up by the video camera recorder 1.

Next, the user needs to record an image by
Press the REC button (see FIG. 2) in the remote control button 33. This information is sent to the control code generator 34, undergoes pulse position modulation (hereinafter referred to as PPM), and the infrared LED 3
5 is transmitted to the video camera recorder 1. In addition, PPM
Since this is a general modulation method of a remote controller, its description is omitted here. In the video camera recorder 1, the PIN photodiode 28 receives the PPM code, and the recorder circuit 3 decodes the PPM code to start recording an image.

When the user wants to change the angle of view while looking at the LCD monitor 31, the zoom button in the remote control button 33 is pressed, and this information is similarly transmitted to the video camera recorder 1. The received PPM code is sent to the camera control circuit 29 and controls the video camera 2 to change the angle of view. The other remote control buttons 33 are controlled in the same manner.

As described above, in the wireless video camera system which performs bidirectional communication, power consumption is consumed when the user moves around and moves away from or approaches the video camera recorder 1, or changes the light receiving angle. The system operation in consideration will be described.

The power source of this video camera recorder 1 is A
Both a C adapter power supply and a portable battery can be attached. When the power supply 37 is attached, the sensor 2
3 sends power supply information to the power supply determination circuit 24. In the power supply discriminating circuit 24, the LED driver 1 is discriminated based on the transmitted power source information as to whether it is an AC adapter power source or a battery.
The discrimination information is sent to 0. Here, the method of discriminating the power supply is different in power supply voltage (depending on the type of battery, there is a large voltage change compared to the AC adapter power supply in general) or the shapes of the battery and the AC adapter power supply are changed in advance, There are various methods such as detecting a difference, and any method may be used.

FIG. 3 shows the LE executed by the LED driver 10.
It is a flow chart which shows a D lighting processing routine. First, it is determined whether the power source is a battery or an AC adapter from the power source determination information (step S1). When the discrimination information is the battery, the LED driver 10 drives only one infrared LED 26 in order to suppress power consumption (step S4).

On the other hand, when the discrimination information is the AC adapter, the LED driver 10 refers to the output of the level detector 38 and discriminates whether or not the PIN photodiode 28 receives the control code (step S2). When the PIN photodiode 28 does not receive the control code, the level detector 38 sends a no-signal code, so
The ED driver 10 is an infrared LED to extend the reach.
Three lights 25, 26 and 27 are emitted (step S5).

On the other hand, when the PIN photodiode 28 receives the control code, the PIN photodiode is PP
The M signal is sent to the level detector 38. Light is received when the remote controller 36 of the user and the video camera recorder 1 are separated from each other or the transmission and reception angles are different from each other.
The amplitude level of the PM signal decreases. Level detector 3
At 8, the amplitude level of the PPM signal is detected (step S3), and the information is sent to the LED driver 10. This detection method is generally envelope detection used in AGC or the like. The LED driver 10 changes the number of the infrared LEDs 25, 26, 27 to emit light according to the attenuation amount (steps S4, S5, S6).

In this embodiment, since there are three infrared LEDs, two amplitude level thresholds are set and
When the level is higher than the second threshold, one infrared LED is emitted so as to reduce power consumption, two LEDs are emitted in the middle level between the thresholds, and three LEDs are emitted when the range is smaller than the second threshold. Light emission. FIG. 4 is a graph showing a PPM signal having a threshold level set.

In this way, a large amount of infrared rays can be output when the remote control is far away, and a small amount of infrared rays can be output when the remote control is near, so that video and audio can be efficiently consumed over a wide range. It will be possible to send to.

In the embodiment described above, the control code from the remote controller 36 cannot be detected unless the user scans the remote controller button 33. However, the remote controller 3
A system in which 6 automatically sends a control code dedicated to detection at a constant cycle can also be realized with the same system configuration. Further, in the present embodiment, the number of infrared LEDs is three, but the number may be other than that. Furthermore, a system that changes the number of LEDs that emit light when a battery is attached, or a system that also provides a level detector on the remote control side to perform the same operation and increase power efficiency on the remote control side is also effective.

[Second Embodiment] The wireless video camera system of the second embodiment will be described below. FIG. 5 is a block diagram showing the electrical configuration of the wireless video camera system of the second embodiment. In the figure, the same components as those in the first embodiment are designated by the same reference numerals. In this embodiment, the level detector 38 is omitted as compared with the first embodiment. Since the other components are the same, the description thereof will be omitted.

An electric signal of an image taken by the video camera 2 is converted into a video signal by the camera signal processing circuit 39 and sent to the recorder circuit 3 to be in a recording standby state. This electric signal is simultaneously projected on the EVF 4, further modulated by the video FM modulator 5 into the FM wave of the carrier 11 MHz, and sent to the adder 9.

On the other hand, when voice is converted into an electric signal by the stereo microphone 6, the audio signal processing circuit 40 performs processing such as directivity and automatic gain control (AGC), and the left and right FM modulators 7 and 8 respectively. Carrier 1.3MHz,
It is modulated into an audio signal of 1.7 MHz. Adder 9
Then, the frequencies of the left and right audio signals and the video signal are subjected to a multiplexing process and sent to the LED driver 10.

As the power source of the video camera recorder 1, both an AC adapter power source and a portable battery can be attached. When the power supply 37 is attached, the sensor 23 sends power supply information to the power supply determination circuit 24. The power supply discriminating circuit 24 discriminates whether the power source is the AC adapter power source or the battery from the information of the power source, and sends the discriminating information to the LED driver 10.

FIG. 6 is a flow chart showing an LED lighting processing routine executed by the LED driver. First, it is determined from the determination information whether the power source is a battery or an AC adapter power source (step S11). When the power source is a battery, the LED driver 10 drives only one infrared LED 26 to reduce power consumption (step S12). Further, when the discrimination information of the power discriminator 24 is an AC adapter, a large amount of electric power can be taken, so that three infrared LEDs 25, 26, 27 are provided to extend the reach.
Is emitted (step S13).

On the remote controller side, the user holds the remote controller 36 and moves to the front of the video camera, and holds the remote controller 34 to receive infrared rays. The PIN photodiode 13 converts the received signal into an electric signal and converts it into three filters HPF.
14, BPF17, and BPF20. The HPF 14 sends the signal from which the low frequency component of the audio signal band is removed to the video FM demodulator 15. The video signal sent from the video FM demodulator 15 is demodulated, and the LCD driver 3
0 is displayed on the LCD monitor 31.

The left sound BPF 17 extracts an audio signal in the left sound band modulated at 1.3 MHz. Left sound FM
The demodulator 18 demodulates the left audio signal and outputs it to the headphone terminal 32. Similarly, the right audio signal is output to the headphone terminal 32 by the right sound BPF 20 and the right sound FM demodulator 21.

The user confirms the image displayed on the video camera recorder 1 on the LCD monitor 31, and connects the headphones to the headphone terminal 32 to confirm the voice picked up by the video camera recorder 1.

Next, the user needs to record an image.
Press the REC button (see FIG. 2) in the remote control button 33. This information is sent to the control code generator 34, undergoes pulse position modulation (PPM), and is sent to the video camera recorder 1 by the infrared LED 35. In the video camera recorder 1, the PIN photodiode 28 receives the PPM code, and the recorder circuit 3 decodes the PPM code and starts recording.

When the user wants to change the angle of view while looking at the LCD monitor 31, he presses the zoom button in the remote control button 33, and the information is sent to the video camera recorder 1 in the same manner. The received PPM signal is sent to the camera control circuit 29 and controls the video camera 2 to change the angle of view. The other remote control buttons 36 are controlled in the same manner.

In this way, when the power supply is the AC adapter, a large amount of infrared rays can be output, and it becomes possible to transmit video and audio over a long distance or a wide range.

Further, in the present embodiment, the number of infrared LEDs is three, but other numbers may be used.

[Third Embodiment] The wireless video camera system of the third embodiment will be described below. FIG. 7 is a block diagram showing the electrical configuration of the wireless video camera system of the third embodiment. The same components as those in the first and second embodiments are designated by the same reference numerals. In this embodiment, the power supply discriminator 24 and the sensor 23 are omitted as compared with the first embodiment. Since the other components are the same, the description thereof will be omitted.

An electric signal of an image taken by the video camera 2 is converted into a video signal by the camera signal processing circuit 39 and sent to the recorder circuit 3 to be in a recording standby state. Further, this electric signal is simultaneously projected on the EVF 4, modulated by the video FM modulator 5 into the FM wave of the carrier 11 MHz, and sent to the adder 9.

On the other hand, when the voice is converted into an electric signal by the stereo microphone 6, the audio signal processing circuit 40 performs processing such as directivity and automatic gain control (AGC), and the left and right FM modulators 7 and 8 are processed. Carrier 1.3MHz,
It is modulated into an audio signal of 1.7 MHz. Adder 9
Then, the frequencies of the left and right audio signals and the video signal are multiplexed, and the multiplexed signal is the LED driver 10
Sent to LED driver 10 is three infrared LEDs
25, 26 and 27 are caused to emit light and the multiplexed signal is output to the space.

On the remote control side, the user holds the remote control 36 and moves in front of the video camera, and holds the remote control 34 to receive infrared rays. The PIN photodiode 13 converts the received signal into an electric signal and converts it into three filters HPF.
14, BPF17, and BPF20. The HPF 14 sends the signal from which the low frequency component of the audio signal band is removed to the video FM demodulator 15. The video FM demodulator 15 demodulates the transmitted video signal, and the LCD driver 3
0 is displayed on the LCD monitor 31. Left sound BP
F17 takes out the audio signal in the left sound band modulated at 1.3 MHz. The left audio FM demodulator 18 demodulates the left audio signal and outputs it to the headphone terminal 32.
Similarly, the right audio signal is output to the headphone terminal 32 by the right sound BPF 20 and the right sound FM demodulator 21.

The user confirms the image displayed on the video camera recorder 1 on the LCD monitor 31, and connects the headphones to the headphone terminal 32 to confirm the voice picked up by the video camera recorder 1.

Next, the user needs to record an image.
Press the REC button (see FIG. 2) in the remote control button 33. This information is sent to the control code generator 34, undergoes pulse position modulation (PPM), and is sent to the video camera recorder 1 by the infrared LED 35. In the video camera recorder 1, the PIN photodiode 28 receives the PPM code, and the recorder circuit 3 decodes the PPM code and starts recording.

When the user wants to change the angle of view while looking at the LCD monitor 31, the user presses the zoom button in the remote control button 33, and this information is sent to the video camera recorder 1 as well. The received PPM signal is sent to the camera control circuit 29 and controls the video camera 2 to change the angle of view. The other remote control buttons 36 are controlled in the same manner.

As described above, in the wireless video camera system for bidirectional communication, the user moves around and moves away from or approaches the video camera 1.
The system operation in consideration of power consumption when changing the light receiving angle will be described.

FIG. 8 shows the LE executed by the LED driver 10.
It is a flow chart which shows a D lighting processing routine. First, the LED driver 10 refers to the output of the level detector 38 to determine whether the PIN photodiode 28 receives the control code (step S21). PIN
When the photodiode 28 does not receive the control code, the level detector 38 sends a code of no signal, so that L
The ED driver 10 emits three infrared LEDs 25, 26, 27 to extend the reach (step S2).
2).

On the other hand, when the PIN photodiode 28 receives the control code, the PIN photodiode 28 sends the PPM signal to the level detector 38. The amplitude level of the PPM signal received decreases as the distance between the remote controller 36 of the user and the video camera recorder 1 increases or the transmission and reception angles deviate. The level detector 38 detects the amplitude level of the PPM signal (step S23) and sends the information to the LED driver 10. LE
The D driver 10 has infrared LEDs 25, 2 according to the amount of attenuation.
The number of lights to be emitted is changed for three of 6, 27.

In this embodiment, since there are three infrared LEDs, two thresholds of the amplitude level are set similarly to the first embodiment, and the power consumption is set when the level is larger than the first threshold. One infrared LED is emitted (step S24) so as to suppress the light emission, two lights are emitted at the middle level between the thresholds (step S25), and three lights are emitted when the range is smaller than the second threshold. (Step S22).

In this way, a large amount of infrared rays can be output when the remote control is far away, and a small amount of infrared rays can be output when the remote control is near, so that video and audio can be efficiently consumed over a wide range. It will be possible to send to.

Further, in the present embodiment, the number of infrared LEDs is three, but other numbers may be used. Further, it is also effective to provide a level detector on the remote controller side to perform the same operation and improve the power consumption efficiency of the remote controller.

[Fourth Embodiment] The wireless video camera system of the fourth embodiment will be described below. In the first, second and third embodiments, the number of LEDs to be emitted is changed according to the LED lighting processing routines shown in FIGS. 3, 6 and 8, respectively, but the power consumption is
Since it is proportional to the square of the current flowing through the LED, the same effect can be obtained by changing the drive current instead of the number of LEDs to emit light.

FIG. 9 is a flow chart showing a processing routine for changing the LED drive current. The processing routines for changing the drive currents in FIGS. 6A, 6B, and 6C correspond to the LED lighting processing routines shown in FIGS. 6, 8, and 3, respectively. That is, the process of turning on one LED (steps S12, S24, S4) is the process of reducing the drive current (steps S74, S6).
4, S54) and the process of lighting three LEDs (steps S13, S22, S5) correspond to the process of increasing the drive current (steps S75, S65, S55).

FIG. 7A shows that the drive current is changed according to the type of power source, and FIG. 9B shows that the drive current is changed according to the amplitude level of the PPM signal.
In FIG. 6C, the drive current is changed depending on the type of power supply and the amplitude level of the PPM signal.

Although the magnitude of the drive current is shown in two ways, since the current value can be changed innumerably, a current control method which is determined by calculation inversely proportional to the detection level is adopted. Good.

[0073]

According to the optical space transmission device of the first aspect of the present invention, when performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting elements are driven by the driving means to determine the level. The level of the control signal received by the means is discriminated, and the driving number changing means changes the driving number of the light emitting element based on the determined information. Therefore, when the level of the control signal is sufficient, the light quantity should be reduced. The power consumption can be suppressed by, and when the level of the control signal is not sufficient, the light amount can be increased to receive light over a wide range.

According to the optical space transmission device of the second aspect,
When performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting element is driven by the driving means, the type of the power source is discriminated by the power source discriminating means, and the number of drives is changed based on the discriminated information. Since the driving number of the light emitting element is changed by the means, power consumption can be suppressed when a battery or the like is used as a power source.

According to the optical space transmission device of the third aspect,
When performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting element is driven by the driving means, the type of power source is discriminated by the power source discriminating means, and the level of the received control signal is discriminated by the level discriminating means. , The number of drives of the light emitting element is changed by the number-of-drives changing means based on the information of the level of the control signal and the kind of the power source thus determined, so that, for example, when applied to a light receiving device having a liquid crystal monitor as a wireless remote controller. For example, when the light receiving device moves and the output becomes insufficient, a large amount of light is output depending on the type of the power source, or the amount of light is reduced to reduce power consumption.
Further, when the level of the control signal is not sufficient, it is possible to receive light over a wide range by increasing the amount of light.

According to the optical space transmission device of the fourth aspect,
When performing spatial transmission using a plurality of light emitting elements and light receiving elements, the driving means drives the light emitting elements, the level determining means determines the level of the received control signal, and based on the determined information, Since the drive current changing means changes the drive current of the light emitting element, the power consumption can be suppressed by reducing the drive current when the level of the control signal is sufficient, and the drive current can be reduced when the level of the control signal is insufficient. By increasing the number, it becomes possible to receive light over a wide range.

According to the optical space transmission device of the fifth aspect,
When performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting element is driven by the driving means, the type of the power source is discriminated by the power source discriminating means, and the drive current is changed based on the discriminated information. Since the drive current of the light emitting element is changed by the means, power consumption can be suppressed when a battery or the like is used as a power source.

According to the optical space transmission device of the sixth aspect,
When performing space transmission using a plurality of light emitting elements and light receiving elements, the light emitting element is driven by the driving means, the type of power source is discriminated by the power source discriminating means, and the level of the received control signal is discriminated by the level discriminating means. However, since the drive current of the light emitting element is changed by the drive current changing means based on the information of the level of the control signal and the type of the power supply which are discriminated, the invention is applied to, for example, a light receiving device having a liquid crystal monitor attached to a wireless remote controller. When the light receiving device moves and the output is insufficient, for example, the drive current is increased to output more light depending on the type of the power supply, or the drive current is reduced to suppress power consumption. Further, when the level of the control signal is not sufficient, it is possible to receive light over a wide range by increasing the drive current.

According to the space optical transmission apparatus of claim 7,
Since the audio signal and the video signal are spatially transmitted, the information can be utilized by sending an image or a sound. For example, when the remote control is far away, it can output a large amount of infrared light, and when it is close, it can output a small amount of infrared light, enabling video and audio to be transmitted over a wide range with efficient power consumption. become.

According to the optical space transmission method of claim 8,
In a spatial light transmission method for performing spatial transmission using a plurality of light emitting elements and light receiving elements, the level of a received control signal is determined, and the number of driven light emitting elements to be driven is changed based on the determined information. Therefore, when the level of the control signal is sufficient, the power consumption can be suppressed by reducing the light amount, and when the level of the control signal is insufficient, the light amount can be increased to receive light over a wide range.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wireless video camera system according to a first embodiment.

FIG. 2 is a front view showing an appearance of a remote controller 36.

FIG. 3 is a flowchart showing an LED lighting processing routine executed by the LED driver 10.

FIG. 4 is a PPM with a threshold level set.
It is a graph which shows a signal.

FIG. 5 is a block diagram showing an electrical configuration of a wireless video camera system of a second embodiment.

FIG. 6 is a flowchart showing an LED lighting processing routine executed by an LED driver.

FIG. 7 is a block diagram showing an electrical configuration of a wireless video camera system according to a third embodiment.

FIG. 8 is a flowchart showing an LED lighting processing routine executed by the LED driver 10.

FIG. 9 is a flowchart showing a processing routine for changing the LED drive current.

FIG. 10 is a block diagram showing a configuration of a conventional wireless video camera system.

[Explanation of symbols]

 1 ... Video camera recorder 2 ... Video camera 10 ... LED driver 13, 28 ... PIN photodiode 24 ... Power supply discriminator 25, 26, 27, 35 ... Infrared LED 33 ... Remote control button 34 ... Control code generator 36 ... Remote control 38 ... Level detector

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Claims (8)

[Claims] 1. An optical space transmission device that performs spatial transmission using a plurality of light emitting elements and light receiving elements, a driving means for driving the light emitting elements, and a level determining means for determining the level of a received control signal. An optical space transmission device comprising: a drive number changing means for changing the drive number of the light emitting element based on the determined information. 2. An optical space transmission device for performing spatial transmission using a plurality of light emitting elements and light receiving elements, a driving means for driving the light emitting elements, a power source discriminating means for discriminating a kind of power source, and the discriminating means. An optical space transmission device comprising: a drive number changing means for changing the drive number of the light emitting element based on information. 3. An optical space transmission device for performing spatial transmission using a plurality of light emitting elements and a light receiving element, a driving means for driving the light emitting elements, a power source discriminating means for discriminating the kind of power source, and a control signal for the received light. An optical system comprising: a level discriminating unit for discriminating a level; and a drive number changing unit for changing the drive number of the light emitting element based on the discriminated control signal level and information on the type of power source. Space transmission device. 4. An optical space transmission apparatus for performing spatial transmission using a plurality of light emitting elements and light receiving elements, a driving means for driving the light emitting elements, a level determining means for determining the level of a received control signal, An optical space transmission device comprising: a drive current changing unit that changes a drive current of the light emitting element based on the determined information. 5. An optical space transmission device for performing spatial transmission using a plurality of light emitting elements and light receiving elements, a driving means for driving the light emitting elements, a power source discriminating means for discriminating a kind of power source, and the discriminating means. An optical space transmission device comprising: a drive current changing unit that changes a drive current of the light emitting element based on information. 6. An optical space transmission device for performing spatial transmission using a plurality of light emitting elements and light receiving elements, a driving means for driving the light emitting elements, a power source determining means for determining the type of power source, and a control signal received. And a drive current changing means for changing the drive current of the light emitting element based on the determined level of the control signal and information on the type of the power supply. Optical space transmission device. 7. The optical space transmission device according to claim 1, which performs spatial transmission of an audio signal and a video signal. 8. An optical space transmission method for performing spatial transmission using a plurality of light emitting elements and light receiving elements, the level of a received control signal is determined, and based on the determined information, the light emitting element to be driven is driven. An optical space transmission method characterized in that the number of drives is changed.