JPH05122129A - Radio selective call receiver - Google Patents

Abstract

PURPOSE:To compact a receiver by using a light emitting means for both of call information and the illumination of a display device and changing driving power in accordance with the cases of call information and display device illumination. CONSTITUTION:A received signal is sent to a decoder 4 through a wireless part 2, and when the signal coincides with the contents of a ROM 5, call informing operation and message display are executed. In the case of displaying a message on a dark position, display device illuminating operation is executed. An operation signal is sent to a driving circuit 6 by the decoder 4 in the case of informing a call or by a photosensor circuit in the case of illuminating the display device to drive the shared light emitting means 7. When the frequency of the operation signal is high, driving power is increased and brightness is also increased, but the frequency is low, the driving power is reduced and the brightness is also reduced. The decoder 4 changes the frequency of the operation signal in accordance with the cases of call information and display device illumination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio selective calling receiver, and more particularly to a radio selective calling receiver having an improved driving means for light emitting means.

[0002]

2. Description of the Related Art As conventional light emitting means of a radio selective calling receiver, there are a means for making a call notification and a means for illuminating a display. FIG. 4 is a block diagram showing an example of a conventional radio selective calling receiver. The signal received by the antenna 1 is demodulated by the wireless device 2, converted into a binary signal of "1" and "0" by the waveform shaping circuit 3, and sent to the decoder 4. When this signal matches the information in the ROM 5 in the decoder 4, a signal is sent to the call notification drive circuit 23 to drive the call notification light emitting means 24. If there is a message, the CPU 10 sends a signal to the LCD drive circuit 12,
Display the message on the CD 13. When the surroundings are dark, the photo sensor 9 operates, so that the CPU 10 sends a signal to the display illumination driving circuit 25, and the display illumination light emitting means 2
6 is driven to illuminate the LCD 13. The decoder 4 uses the decoder operation clock circuit 8
Each of them is operated by the U operation clock circuit 11.

FIG. 5 is a circuit diagram showing an example of a light emitting means drive circuit. When a pulse signal having a certain period is sent to the base of the transistor 27 to cause a light emitting operation, an electromotive force is generated in the coil 20 connected to the collector when the pulse signal falls, and the electromotive force is generated. This causes the light emitting means 21 to operate.

FIG. 6 is a circuit diagram showing an example of a photo sensor circuit. When the base of the phototransistor 28 is exposed to light, a photocurrent proportional to the irradiance flows through the collector. This current is amplified by the transistor 29, causing a voltage drop Vph across the resistor 30. The level of this voltage drop controls the lighting operation. The photocurrent at a certain irradiance is IB, the current amplification factor of the transistor 29 is hFE, and the resistance 30 is
Let IL be the current flowing through, then IL = hFE × IB. When dark, the irradiance is small, so IB → small, so IL → small. Therefore, the voltage drop Vph is Vph (31) = resistance (30) × IB → 0. On the contrary, when it is bright, the irradiance is large, so IB → becomes large, and thus IL → becomes large. Therefore, the voltage drop Vph
Becomes Vph (31) = resistance (30) × IB → VDD (32). Therefore, the illumination operation is performed when Vph (31) is at the "L" level.

[0005]

As is apparent from the above description, the conventional radio selective call receiver has the call notification light emitting means and the display illumination light emitting means which are independent of each other. Therefore, an increase in the mounting area due to an increase in the number of parts has been a problem in reducing the size of the receiver. SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a radio selective call receiver which is smaller than the conventional one by reducing the number of parts constituting a circuit.

[0006]

In order to achieve the above object, a radio selective call receiver according to the present invention is a radio selective call receiver having light emitting means for call notification and display illumination, wherein the call notification light is emitted. The element and the light emitting element for illuminating the display are configured such that one calling element is used in common. In the above structure, the dual-use light emitting element is
In the case of the call notification, it is driven by a first drive power, and in the case of the display illumination, it is driven by a second drive power smaller than the first drive power.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a radio selective calling receiver according to the present invention. The signal processing operation and the message display operation from the antenna 1 to the decoder 4 are the same as the conventional one. When the call notification is performed, a signal for the call notification from the decoder 4 is sent to the drive circuit 6 from the photosensor circuit 9 when the display illumination is performed, and the signal for the display illumination is sent to the drive circuit 6. Is driven.

FIG. 2 is a waveform diagram showing an example of the light emitting operation of FIG. This example will be described using the circuit of FIG. 5 used as a drive circuit. When a pulse signal 14 having a certain period is sent to the base side of the transistor 27, an electromotive force 15 is generated in the coil 20 when the pulse signal falls, and the electromotive force causes the light emitting means 21 to operate. The generated electromotive force 15 decreases as it is consumed. However, since the electromotive force is generated each time the pulse signal 14 falls, the shorter the time between adjacent pulses, that is, the shorter the cycle of the pulse signal, the lower the average power. As a result, the brightness of the light emitting means 21 increases.

A pulse signal 16 having a longer cycle than the signal 14.
Is transmitted, the time from when an electromotive force is generated at a certain time until the next electromotive force is generated becomes longer. That is, the average power for the electromotive force of the waveform 17 becomes small, and the brightness of the light emitting means 21 becomes small. Therefore, in the case of a call notification that requires a large luminance in order to reliably notify the reception, the cycle of the operation signal sent to the drive circuit is shortened. That is, the frequency of the signal is increased. When illuminating the display, the frequency of the operation signal is set lower than that of the ringing because the brightness sufficient to confirm the message is sufficient. The frequency of the operation signal is the decoder 4
The clock of the operation clock circuit 8 is used. The clock is frequency-divided by the frequency dividing circuit in the decoder 4 and sent as an operation signal to the peripheral circuits. The frequency after frequency division can be changed by changing the frequency division number. If the frequency division number is increased, the frequency after the frequency division is lowered. Therefore, in the case of the display illumination, the frequency division number is increased and the frequency of the operation signal is lowered as compared with the case of the call notification. The frequency division number is a value that provides the required brightness.

FIG. 3 is a circuit diagram showing an embodiment of the drive power changing means of the radio selective calling receiver according to the present invention. In the case of call notification, an operation signal (pulse signal) is sent from the decoder 4 to the base of the transistor 18, and the light emitting means 21 is driven by the electromotive force generated in the coil 20 at the fall of the pulse signal. In the case of display lighting, an operation signal is sent from the decoder 4 to the base of the transistor 19, and the light emitting means 21 is driven by the electromotive force generated in the coil 20 at the time of pulse fall as in the call notification. A resistor 22 is connected to the resistor 22. The resistor 22 reduces the drive current from that at the time of short circuit, and the electromotive force is reduced. Therefore, the brightness of the light emitting means 21 becomes small. Therefore, the magnitude of the electromotive force can be changed by changing the drive current in this way, and the brightness of the light emitting means can be changed.

[0011]

As described above, according to the present invention, since the light emitting element for calling notification and the light emitting element for illuminating the display are combined into one light emitting element, the receiver can be miniaturized. Further, by configuring the power for driving the dual-purpose element to change between the call notification and the display lighting, the brightness can be changed between the call notification and the display lighting.
Efficiency is also improved.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a radio selective calling receiver according to the present invention.

FIG. 2 is an operation waveform chart showing an example of the light emitting operation of FIG.

FIG. 3 is a circuit diagram showing an embodiment of driving power changing means of the radio selective calling receiver according to the present invention.

FIG. 4 is a block diagram showing an example of a conventional radio selective calling receiver.

FIG. 5 is a block diagram showing an example of a light emitting means drive circuit.

FIG. 6 is a circuit diagram showing an example of a photo sensor circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Antenna 2 ... Radio | wireless part 3 ... Waveform shaping circuit 4 ... Decoder 5 ... ROM 6 ... Drive circuit 7 ... Combined light-emitting means 8 ... Decoder operation clock circuit 9 ... Photo sensor circuit 10 ... CPU 11 ... CPU operation clock circuit 12 ... LCD drive circuit 13 ... LCD 14, 16 ... Pulse signal waveform 15, 17 ... Electromotive force waveform generated in coil 18, 19, 27, 29 ... Transistor 20 ... Coil 21 ... Light emitting means 22, 30 ... Resistor 23 ... Ring notification drive circuit 24 ... Light emitting means for call notification 25 ... Display lighting drive circuit 26 ... Light emitting means for display lighting 28 ... Phototransistor

Claims (2)

[Claims] 1. A radio selective call receiver having light emitting means for call notification and display illumination, wherein one light emitting element for call notification and the light emitting element for display illumination are combined. A radio selective call receiver characterized by being configured. 2. The dual-purpose light emitting element is driven by a first drive power in the case of the call notification, and is driven by a second drive power smaller than the first drive power in the case of the display illumination. 4. A method according to claim 1, further comprising means.
The radio selective call receiver described.