JPH05183515A - Optical space transmitter - Google Patents

Abstract

PURPOSE:To surely specify a reception direction based on each output level difference of a light receiving element by sending a light for direction adjust ment to a comparatively wide angle area and using plural light receiving elements arranged spatially different locations so as to detect the light, thereby facilitating the reception of the projection light for direction adjustment. CONSTITUTION:A light sent from a light emitting element 3 over a comparatively narrow angular area is received by a light receiving element 9 to regenerate a transmission signal and a light 30 set over a comparatively wider angular area than the projection angular area of the light emitting element 3 from the direction adjustment light emitting element 12 is received by a direction detection light receiving element array 26 in which plural light receiving elements 21-24 are arranged at different locations and the light receiving direction of the light receiving element 9 is controlled through a servo control circuit 40 based on the level difference of the signal.

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 more particularly to an optical space transmission device, which is applied to a wireless speaker for spatially transmitting an audio signal by using infrared rays so as to efficiently adjust an angle between a light emitting portion and a light receiving portion. The present invention relates to a suitable optical space transmission device.

[0002]

2. Description of the Related Art FIG. 5 is a schematic block diagram of such a conventional optical space transmission device. In the figure, 31 is a voice input circuit that receives a voice signal from the outside, and 32 is a voice input circuit 31.
An A / D conversion circuit for converting an analog audio signal input from the digital audio signal, 33 is an A / D conversion circuit 32
It is an input / output unit that amplifies the digital audio signal from and supplies it to the modulation circuit 34. Reference numeral 1 denotes a light emitting unit that projects infrared light including a signal component that is modulated by the modulation circuit 34 into a form suitable for optical transmission, and 11 is a light receiving unit that receives the projected infrared light 6 from the light emitting unit 1. In the light emitting section 1, 3 is a light emitting element for generating a light emitting infrared ray 4, and 5 is a light projecting condenser lens for collecting the light emitting infrared ray 4 from the light emitting element 3 and projecting it into a space as a light projecting infrared ray 6. .. Further, in the light receiving section 11, 7 is a light receiving condenser lens for collecting the projected infrared ray 6 from the space and receiving it as a received infrared ray 8, and 9 is a signal for receiving the received infrared ray 8 through the light receiving condenser lens 7. It is a light receiving element that obtains a component. Reference numeral 2 is a preamplifier that amplifies the signal component obtained by the light receiving element 9 in the light receiving section 11, and 13 is a digital audio signal obtained by demodulating the signal modulated by the modulation circuit 34 on the light emitting section 1 side. A demodulation circuit for obtaining the digital audio signal, an input / output unit 14 for extracting the digital audio signal,
Is a D / A conversion circuit for converting a digital audio signal taken out from the input / output unit 14 into an analog audio signal, 16 is an audio output circuit for amplifying the analog audio signal and outputting it as an audio signal to the outside, 17 is demodulation A level comparator for detecting the level of the digital audio signal obtained by the circuit 13 and outputting a signal according to the level, and 19 is a direction changing drive for swinging the light-receiving angle of the light-receiving unit 11 vertically or horizontally. Mechanism, 18 is a direction changing drive circuit for giving a drive signal to the direction changing drive mechanism 19, 41 is the level detector 1
The hill-climbing servo control circuit 41 applies a control signal to the direction changing drive circuit 18 so that the signal level detected in 7 becomes the highest.

FIG. 6 is an external view of the light receiving portion 11, but as shown in the figure, the light receiving portion 11 is mounted on the base through a direction changing drive mechanism 19 so that the direction of the light receiving window 20 can be freely changed. It is mounted so that the vertical and horizontal directions can be changed by a drive signal from the direction changing drive circuit 18.

The operation of the above-described structure will be described below.

A voice signal input on the side of the light emitting unit 1 is amplified to a proper level by a voice input circuit 31 and given to an A / D conversion circuit 32. The analog audio signal is converted into a digital audio signal in the A / D conversion circuit 32 and output to the modulation circuit 34 through the input / output unit 33. Modulation circuit 34
At, the digital audio signal is modulated into a form suitable for transmission and given to the light emitting element 3. As a result, the light emitting element 3 generates the emitted infrared ray 4 in a modulated form and sends the projected infrared ray 6 to the space of a limited angle region through the light projecting condenser lens 5.

On the side of the light receiving portion 11, the light receiving infrared ray 8 obtained by condensing the projected infrared ray 6 emitted from the light emitting portion 1 into the space by using the light receiving condenser lens 7 is received by the light receiving element 9. As a result, a modulated light receiving signal is obtained from the light receiving element 9, but this signal is amplified by the preamplifier 2 and the demodulation circuit 1
Demodulated in 3 to obtain a digital voice signal. This digital voice signal is output to the D / A conversion circuit 15 through the input / output unit 14 and converted into an analog voice signal here.
The analog audio signal is amplified by the audio output circuit 16 and output as an audio signal to, for example, a speaker.

On the other hand, the digital voice signal obtained by the demodulation circuit 13 is given to the level detector 17. The level detector 17 detects the level of the digital audio signal demodulated by the demodulation circuit 13 and outputs a signal corresponding to this level. This signal is given to the hill-climbing servo control circuit 41.

While the hill-climbing servo control circuit 41 monitors the signal level from the level detector 17, it gives a drive signal to the direction change drive mechanism 19 through the direction change drive circuit 18 to change the direction of the light receiving portion 11. At this time, When the signal level is high, it is judged as the control direction, and when the signal level is low, it is judged as the non-control direction, so that the signal level of the level detector 17 is the highest. Perform servo control.

The receiving state of the light receiving section 11 largely depends on whether or not the light receiving window 20 of the light receiving section 11 accurately faces the light emitting section 1, and if the receiving state is poor, a good voice signal is produced. It cannot be reproduced. Therefore, in the light receiving section 11, the light receiving direction is changed through the direction changing drive mechanism 19 to the direction in which the signal level detected by the level detector 17 becomes the highest, so that the best receiving state can be always maintained. it can.

[0010]

As described above, the conventional optical space transmission apparatus has a projection infrared ray 6 containing a transmission signal projected from the light emitting element 3 through the light projecting condenser lens 5 into a limited space. Is configured to be converted into an electric signal by the light receiving element 9 through the light receiving condensing lens 7 and used for level detection. Therefore, the hill climbing servo control circuit 41 causes the direction change drive circuit 18 and the direction change drive mechanism 19 to operate. When controlling the receiving direction while moving the light receiving unit 11, it is difficult to specify the direction because the projection angle region of the projected infrared rays 6 is limited and a relatively low level transmission signal is used. There was a problem that adjustment took time. Further, the light emitting element 3 has a wide band for signal transmission, and therefore the light emission output is small, and the light receiving element 9 also has a wide band, so that there is a problem that the receiving sensitivity is small. Not suitable for use.

The present invention has been made in order to solve the above-mentioned problems. Instead of a narrow band, a high-power light emitting element transmits light for direction adjustment to a relatively wide angle region, and at the same time, it is used as a space. By detecting multiple light-receiving elements that are placed at different positions, it is easy to receive the projection light for direction adjustment, and the output direction difference of each light-receiving element ensures the identification of the receiving direction. Another object of the present invention is to obtain an optical space transmission device having excellent controllability.

[0012]

In order to achieve the above object, an optical space transmission device according to a first aspect of the present invention projects light modulated based on a transmission signal by a light projecting means, and projects the light. In an optical space transmission device that receives light by a light receiving means and demodulates it, a second light projecting means that projects light having a narrower modulation band than the modulated band of the modulated light and a wide projection angle. Second light receiving means for detecting a level difference between a plurality of signals obtained by receiving light from the second light emitting means by a plurality of light receiving elements arranged at spatially different positions, and the second light receiving means. And a control means for controlling the light receiving direction of the light receiving means based on the level difference thus obtained.

In order to achieve the above object, an optical space transmission device according to a second aspect of the present invention projects light modulated based on a transmission signal by a light projecting means, and receives the projected light. In an optical space transmission device that receives and demodulates by
Second light projecting means for projecting light having a wider modulation band and a wider light projecting angle than the modulated band of the modulated light, and the light from the second light projecting means are arranged at spatially different positions. Second light receiving means for detecting a level difference between a plurality of signals received by the plurality of light receiving elements, and a light receiving direction of the light receiving means based on the level difference obtained by the second light receiving means And a direction detecting unit that operates.

[0014]

As described above, it is difficult to move the direction of the light receiving element to adjust the optimum light receiving direction because the light emitting element emits light in a high band with a limited projection angle. In the present invention, the light for adjusting the direction is separately provided, and the light is received to adjust the direction of the light receiving means.

That is, since the second light projecting means projects light in a narrow band and at a wide light projecting angle, it is possible to receive the light and easily detect the direction dependency of the level. A plurality of light receiving elements are arranged at spatially different positions in the second light receiving means, and the level difference between the signals obtained by these light receiving elements depends on the light projecting direction of the light from the second light projecting means. Since it changes, the light receiving direction can be detected according to the level difference, and the light receiving means can be automatically controlled in the optimum light receiving direction.

[0016]

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

FIG. 1 is a schematic configuration diagram of an optical space transmission apparatus according to an embodiment of the present invention. In the figure, reference numeral 12 is a light emitting element for adjusting direction, which is attached inside the light emitting section 1 in the vicinity of the light emitting element 3 to project and transmit the infrared light 30 for direction adjustment to a relatively wide angle region, and 26 is a light receiving element in the light receiving section 11. The infrared light 30 for adjusting direction, which is attached in the vicinity of 9, is received by four light receiving elements, that is, the first light receiving element 21, the second light receiving element 22, the third light receiving element 23, and the fourth light receiving element 24, and each is received as an electric signal. It is a light receiving element array for direction detection that is converted into. Reference numeral 25 is a direction detecting lens for guiding the direction adjusting infrared light 30 emitted from the direction adjusting light emitting element 12 to the direction detecting light receiving element array 26. Reference numeral 10 is a modulation circuit for causing the direction adjusting light emitting element 12 to emit light by applying a modulation of a proper band having a narrow band, 27 is a switch for turning on / off the operation of the modulation circuit, and 28 is a direction detecting light receiving element array. A preamplifier group that amplifies the optical signal received by 26, 29 is a demodulation circuit group that demodulates the received light signal obtained through the preamplifier group, and 40 is the levels of a plurality of demodulated signals obtained by the demodulation circuit group 29. Direction changing drive circuit 1 so that the respective level differences are eliminated based on the difference
8 is a servo control circuit 40 that outputs a control signal.

The operation of the above-described structure will be described below with reference to the direction detection light-receiving element array 26 shown in FIG. By the way, as shown in FIG. 2, the first light receiving element 21, the second light receiving element 22, the third light receiving element 23, and the fourth light receiving element 24, which constitute the direction detecting light receiving element array 26, are the same as the first light receiving element 21 and the first light receiving element 21. 2 light receiving element 22
Are arranged at different positions in the horizontal direction, and the third light receiving element 23
And the fourth light receiving element 24 are arranged at different positions in the vertical direction, and the first light receiving element 21 and the third light receiving element 23, the third light receiving element 23 and the second light receiving element 22, the second light receiving element 22 and the fourth light receiving element 24, the 4th light receiving element 24, and the 1st light receiving element 21 are arrange | positioned so that it may each come in a diagonal direction. And
(A), (B), depending on the relationship between the direction-adjusting infrared image 30 and the direction-detecting optical image 35 by the direction-detecting lens 25,
The states of (C), (D), and (E) are shown.

The audio signal input on the side of the light emitting unit 1 is amplified to a proper level by the audio input circuit 31 and then A / D.
It is given to the conversion circuit 32. The analog audio signal is converted into a digital audio signal in the A / D conversion circuit 32 and output to the modulation circuit 34 through the input / output unit 33. In the modulation circuit 34, the digital audio signal is modulated into a form suitable for transmission and given to the light emitting element 3. As a result, the light emitting element 3 generates the emitted infrared ray 4 in a modulated form and sends the projected infrared ray 6 to the space of a limited angle region through the light projecting condenser lens 5.

On the other hand, the direction adjusting light emitting element 12 mounted in the vicinity of the light emitting element 3 is lit while being modulated by the modulation circuit 10 only while the switch 36 is on, and the infrared ray 6 projected by the light emitting element 3 is emitted. The direction adjusting infrared light 30 is projected and transmitted to an angle region relatively wider than the light projecting angle region. The light output level in this case is relatively strong because it is only modulated in a narrow band.

On the other hand, on the side of the light receiving section 11, the light receiving infrared ray obtained by condensing the projected infrared ray 6 emitted from the light emitting section 1 into the space from the relatively narrow angle region by using the light receiving condenser lens 7. 8 is received by the light receiving element 9. As a result, a modulated light receiving signal is obtained from the light receiving element 9, and this signal is demodulated by the demodulation circuit 13 to obtain a digital voice signal. This digital voice signal is passed through the input / output unit 14 to D
It is output to the A / A conversion circuit 15 and converted into an analog audio signal here. This analog audio signal is further amplified by the audio output circuit 16 and output as an audio signal to, for example, a speaker.

On the other hand, the direction-detecting light-receiving element array 26 mounted in the vicinity of the light-receiving element 9 emits light at a relatively stronger level than the infrared ray 6 in an angle area relatively wider than the angle area of the infrared ray 6. Infrared light 30 for direction adjustment
Is received through the first light receiving element 21, the second light receiving element 22, the third light receiving element 23, and the fourth light receiving element 24. This light receiving signal is amplified by the preamplifier group 28 into four systems,
Demodulation detection is performed in the demodulation circuit group 29, and the demodulated detection is applied to the servo control circuit 40. The servo control circuit 40 compares the levels of the digital audio signals demodulated by the demodulation circuit group 29 and sends a control signal to the direction changing drive circuit 18 in a direction such that the respective level differences are the smallest.

Now, the direction detecting light image 35 on the direction detecting light receiving element array 26 by the direction adjusting infrared light 30 is shown in FIG.
It is assumed that the state is (B) or (C). In this case, the levels of light detected by the third light receiving element 23 and the fourth light receiving element 24 do not change, and there is a difference in the levels detected by the first light receiving element 21 and the second light receiving element 22. That is, it indicates that the direction of the light receiving unit 11 is incorrect in the left-right direction. Therefore, the servo control circuit 40 gives the direction change drive circuit 18 a control signal to the right or to the left depending on the level difference between the outputs of the first light receiving element 21 and the second light receiving element 22. As a result, the direction changing drive circuit 18 gives the direction changing drive mechanism 19 a rotation drive signal in the left-right direction, and the light receiving unit 1
1 shakes the head in the left-right direction, and the direction detection optical image 35 is shown in FIG.
When the state of (A) is reached and the detection level difference between the first light receiving element 21 and the second light receiving element 22 disappears, the operation is stopped based on a command from the servo control circuit 40. On the other hand, it is assumed that the direction detection light image 35 on the direction detection light receiving element array 26 by the direction adjustment infrared light 30 is in a state as shown in FIG. 2D or 2E. In this case, the levels of the light detected by the first light receiving element 21 and the second light receiving element 22 do not change, and there is a difference in the levels detected by the third light receiving element 23 and the fourth light receiving element 24. That is, it indicates that the direction of the light receiving unit 11 is incorrect in the vertical direction. Therefore, the servo control circuit 4
0 gives the direction change drive circuit 18 an upward or downward control signal according to the level difference between the outputs of the third light receiving element 23 and the fourth light receiving element 24. As a result, the direction change drive circuit 18 gives a vertical direction rotation drive signal to the direction change drive mechanism 19, the light receiving unit 11 swings its head in the up and down direction, and the direction detection optical image 35 becomes the state of FIG. 2 (A). The third light receiving element 23
When there is no difference in the detection levels of the fourth light receiving element 24 and the fourth light receiving element 24, the operation is stopped based on a command from the servo control circuit 40. The above control is similarly performed when the orientations are not correct in both the left and right sides and the top and bottom sides. Finally, the level difference between the first light receiving element 21 and the second light receiving element 22 is eliminated and the third control is performed. The control is performed in such a direction as to eliminate the level difference between the light receiving element 23 and the fourth light receiving element 24.

When the control as described above is completed, the operation of the modulation circuit 10 is stopped by the switch 27 so that the transmission of the signal to be originally transmitted is not disturbed.

The receiving state of the transmission signal in the light receiving section 11 depends largely on whether or not the light receiving section 11 is accurately facing the light emitting section 1, and if the receiving state is poor, a good voice signal should be reproduced. I can't. On the other hand, according to the configuration of the present embodiment, the level of the narrow modulation band is high because the light emitting element 3 projects a relatively wide area different from the transmission signal projected in a relatively narrow spatial angle area. Infrared light 30 for direction adjustment
Is converted into an electric signal by the light receiving element array 26 for direction detection,
By using this for direction control and controlling the angle of the light receiving unit 11 in the vertical and horizontal directions through the servo control circuit 40,
The best reception condition can be obtained. That is, the light receiving unit 1
When the direction 1 is moved and controlled to the optimum receiving direction, the direction adjusting infrared light 30 can be easily detected, the direction can be specified with certainty, and the direction control can be easily performed. After the direction adjustment is completed, switch 2
By stopping the operation of the modulation circuit 10 and stopping the light emission of the direction adjusting light emitting element 12 by 7, it is possible to reduce the power consumption and the influence on the regular transmission signal due to the intermodulation or the like.

In the above embodiment, the direction adjusting light emitting element 12 is lit while being modulated by the modulation circuit 10 in a narrow band. However, if it is not necessary to consider noise due to external light, The same effect can be obtained even if the lights are turned on in a direct current manner. Further, in the above embodiment, the lens is not used to obtain the direction adjusting infrared light 30 from the direction adjusting light emitting element 12, but it is possible to project a wider range than the light projecting condenser lens 5. Such a lens may be applied. On the other hand, although the direction detecting lens 25 is disposed in front of the direction detecting light receiving element array 26 on the side of the light receiving section 11, when the light receiving section 11 faces the direction adjusting light emitting element 12, the direction detecting light receiving light is received. The same effect can be obtained by arranging a mask that makes the light incident on the first light receiving element 21, the second light receiving element 22, the third light receiving element 23, and the fourth light receiving element 24 of the element array 26 uniform. it can.

In the above embodiment, the first light receiving element 21, the second light receiving element 22, the third light receiving element 23, and the fourth light receiving element 24 of the direction detecting light receiving element array 26 are included in one direction detecting lens 25. Although the configuration in which they are collectively arranged behind is illustrated, as shown in FIG. 3, the first light receiving element 21, the second light receiving element 22, the third light receiving element 23, and the fourth light receiving element 24 are cross-shaped.
And the first condenser lens 36, the second condenser lens 37, and the third condenser lens 3 in front of the respective elements.
8. When the fourth condensing lens 39 is provided and the projected infrared rays 6 are best received by the light receiving element 9 through the light receiving condensing lens 7, the first light receiving element 21 and the second light receiving element 2
2, the third light receiving element 23 and the fourth light receiving element 24 may be adjusted and arranged so that the levels of the direction adjusting infrared light 30 received are the same, and the same effect can be obtained. Further, as shown in FIG. 4, the light receiving element array 26 for direction detection is used.
The first light receiving element 21, the second light receiving element 22, and the third light receiving element
The light receiving element 23 and the fourth light receiving element 24 may be arranged in a cross shape so as to surround the light receiving element 9, and the same effect can be obtained. In this case, if the light emitting element 3 and the direction adjusting light emitting element 12 are arranged sufficiently close to each other on the side of the light emitting unit 1, the light receiving condenser lens 7, the first condenser lens 36, and the second condenser lens It is also possible to configure 37, the third condenser lens 38, and the fourth condenser lens 39 with one lens. In this case, the first light receiving element 21, the second light receiving element 22, the third light receiving element 23, and the fourth light receiving are received when the projected infrared rays 6 are best received by the light receiving element 9 through the light receiving condensing lens 7. It is necessary to arrange each element so that the light receiving level of the element 24 becomes equal.

In each of the above embodiments, the first light receiving element 21 and the second light receiving element 2 of the direction detecting light receiving element array 26 are used.
Although the configuration in which the position of the optical image of the direction adjusting infrared light 30 is detected in order to make the level difference between the second and third light receiving elements 23 and 24, the first light receiving element 21 and the second light receiving element are illustrated. By making the light receiving angles of 22, 22, the third light receiving element 23, and the fourth light receiving element 24 different in the vertical and horizontal directions, it is possible to detect the direction without using a lens or a mask.
That is, as shown in the explanatory view of FIG. 7, the direction adjusting infrared light 30 from the direction adjusting light emitting element 12 is emitted from the first light receiving element 2.
The highest detection level can be obtained when vertically incident on each of the first, second light receiving element 22, the third light receiving element 23, and the fourth light receiving element 24, but since each light receiving element is angled. If all the elements do not have an optimum angle, it is impossible to eliminate the difference in output level between them and there is only one direction. Therefore, the emission direction of the direction adjusting infrared light 30 can be identified from the level difference between the light receiving elements.

In the above embodiment, the case where the audio signal is transmitted in the optical space is explained as an example, but other kinds of signals,
For example, it may be applied to a device that transmits a video signal, a control signal for a computer, a data signal, etc., and the same effect can be obtained.

In the above embodiment, the servo control circuit 40 determines the level difference among the first light receiving element 21, the second light receiving element 22, the third light receiving element 23, and the fourth light receiving element 24 which form the direction detecting light receiving element array 26. However, the direction of the light receiving unit 11 may be manually adjusted by displaying the output of the demodulation circuit group 29.

[0031]

As described above, according to the present invention,
In addition to the optical transmission signal, direction adjusting light is configured to be projected to an angle area wider than the angular area where the optical transmission signal is projected, and the light is configured to be received by a plurality of light receiving elements. Therefore, it is easy to identify the direction of the light emitting source of the optical transmission signal from the level difference, and the direction adjustment of the receiving unit can be simplified or automated.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an optical space transmission device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a direction detecting light receiving element array.

FIG. 3 is an explanatory diagram of another example of the direction detection light-receiving element array.

FIG. 4 is an explanatory diagram of still another example of the direction detection light-receiving element array.

FIG. 5 is a schematic configuration diagram of a conventional space optical transmission apparatus.

FIG. 6 is an external view of a light receiving unit.

FIG. 7 is an explanatory diagram of another example of the direction detection light-receiving element array.

[Explanation of symbols]

 1 Light Emitting Unit 2 Preamplifier 3 Light Emitting Element 4 Light Emitting Infrared 5 Light Emitting Condensing Lens 6 Light Emitting Infrared 7 Light Receiving Condensing Lens 8 Light Receiving Infrared 9 Light Receiving Element 10 Modulation Circuit 11 Light Receiving Section 12 Direction Adjustment Light Emitting Element 13 Demodulation Circuit 14 Input / output unit 15 D / A conversion circuit 16 Audio output circuit 17 Level detector 18 Direction changing drive circuit 19 Direction changing drive mechanism 20 Light receiving window 21 First light receiving element 22 Second light receiving element 23 Third light receiving element 24 Fourth Light receiving element 25 Direction detecting lens 26 Direction detecting light receiving element array 27 Switch 28 Preamplifier group 29 Demodulation circuit group 30 Direction adjustment infrared light 31 Voice input circuit 32 A / D conversion circuit 33 Input / output section 34 Modulation circuit 35 direction Optical image for detection 36 First condensing lens 37 Second condensing lens 38 Third condensing lens 39 Fourth condensing lens 4 The servo control circuit 41 hill climbing servo control circuit

Claims (2)

[Claims] 1. An optical space transmission device in which light modulated on the basis of a transmission signal is projected by a light projecting means, and the projected light is received by a light receiving means and demodulated, wherein the modulated light is modulated. A second light projecting means for projecting light having a narrower modulation band and a wider light projecting angle than the band, and a plurality of light receiving elements for arranging light from the second light projecting means at spatially different positions. A second light receiving means for detecting a level difference between a plurality of signals received and received; and a control means for controlling a light receiving direction of the light receiving means based on the level difference obtained by the second light receiving means. An optical space transmission device characterized by the above. 2. An optical space transmission device in which light modulated on the basis of a transmission signal is projected by a light projecting means, and the projected light is received by a light receiving means and demodulated, wherein the modulated light is modulated. A second light projecting means for projecting light having a narrower modulation band and a wider light projecting angle than the band, and a plurality of light receiving elements for arranging light from the second light projecting means at spatially different positions. A second light receiving means for detecting a level difference between a plurality of signals received and received; and a direction detecting means for detecting a light receiving direction of the light receiving means based on the level difference obtained by the second light receiving means. An optical space transmission device having.