JP2003101836A - Compact strobe device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized and inexpensive strobe device for a camera for portable terminal equipment and capable of preventing the occurrence of noise due to the emission of strobe light. SOLUTION: Three LEDs 4 are arranged around a photographing lens 2 of a digital camera 1 at an 120 deg. interval. In the case of photographing a subject in a dark place, pulses are emitted from the LEDs 4 to irradiate the subject with the pulses and fetch an image. Since the strobe device is miniaturized and does not require a complicated circuit a compared with a xenon tube, the device is inexpensive. Moreover emission nose which may exert an adverse effect to a portable telephone is not generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact strobe device for a digital camera used in a mobile terminal device such as a mobile phone.

[0002]

2. Description of the Related Art Digital cameras of a type mounted in a mobile phone or a type incorporated therein are put into practical use. Since the mobile phone communicates with the base station using the extremely high frequency band of GHz, it is easily affected by noise caused by strobe emission such as a xenon tube during a call. Therefore, even though shooting with a mobile phone is possible with a built-in or built-in digital camera, the flash shooting was not taken into consideration at the beginning.

[0003]

However, in actual use, although there is a request to enable shooting in a dark place such as a karaoke room or at night, shooting in a dark place cannot be performed. In the case of stroboscopic photography, xenon tubes are the mainstream of conventional strobes, and a large amount of charge flows through the circuit in a short time due to strobe emission, causing a sudden voltage change, which causes noise, which is transmitted and received by mobile phones. It affects the circuit.

Further, since there are many mounting parts such as a charging circuit, a discharging circuit, and a trigger circuit, the strobe device occupies a large area. Furthermore, the large number of mounted components also increases the cost. Miniaturization is required for both the camera that is installed in the mobile phone and the camera that is built in.

By the way, when photographing an object with a mobile phone, the distance to the object is practically a short distance (0.5 to 2).
m), and it is sufficient to follow this range.
The present invention is based on the above-mentioned demands, and its purpose is to provide a compact,
An object of the present invention is to provide a small-sized strobe device for a camera for a mobile terminal device, which is low in cost and does not generate noise due to strobe light emission.

[0006]

In order to achieve the above object, a compact strobe device according to the present invention comprises one or more LEs around a photographing lens of a digital camera for a portable terminal device.
By arranging D, pulsed light emission is performed and a current several times as large as a steady-state current is flowed to secure the subject brightness, and continuous photography of light emission photography of still images is possible. In addition, the present invention is directed to a peripheral of a taking lens of a digital camera for a mobile terminal device.
By arranging more than one LED and performing pulsed light emission in synchronization with the number of frames of a moving image, the light emission shooting of the moving image is possible. Furthermore, the present invention is a type with a built-in portable terminal device,
Alternatively, in a wearable type digital camera, one or more LEDs are arranged around the photographing lens to perform illumination display such as rotation display in order in addition to light emission photography. Furthermore, the present invention relates to a digital camera with a built-in portable terminal device or a wearable type, wherein one or more LEs are provided around the photographing lens.
D is arranged to emit light for displaying the elapsed time at the time of timer shooting in addition to light emission shooting. The LED in the present invention is a white LED or a single color LED of red, blue, and green, and the color balance is optimized by controlling the white balance of the digital camera.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external perspective view showing an embodiment of a compact strobe device according to the present invention. This embodiment is of a type in which a camera alone is used for taking a picture, mounting it on a mobile phone, and transferring the taken image. The outer surface of the digital camera 1 is in the shape of a gourd, the taking lens 2 is arranged in the approximate center, and three LEDs (white) 4 are embedded at 120 degree intervals around the taking lens 2. This LED
A finder 3 is arranged next to the display 4. A switch 5 for turning on the power is provided in the lower portion, and a shutter button 6 is arranged next to the switch 5.

FIG. 2 is a cross-sectional view near the photographing lens of the compact strobe device according to the present invention. The taking lens holder 8 is mounted on the substrate 7, and the taking lens is the window 1 of the camera exterior 1a.
It faces from b. Further, the LED 4 faces the window 1c. The LED 4 automatically emits light at the time of shooting when the surroundings are dark. It is also possible to forcibly make the light emit or not to make it emit light. Even when the shutter is not released, blinking can be repeated to perform illumination display. Further, in the case of performing timer photographing, for example, in the case of a 10-second timer, it is possible to slowly control the LEDs to be sequentially turned on at the start of the timer for rotation display, and to control the rotation speed to increase immediately before the shutter.

FIG. 3 is a block diagram showing an embodiment of a circuit of the digital camera shown in FIG. An MPU (microprocessor unit) 10 controls a digital camera's photographing operation, strobe (LED) emission, image storage, image transfer, and the like. When the shutter button 6 is pressed and released, the MPU 10 obtains the synchronization signal 12 at the driving timing of the image sensor 11 and activates the pulse generation circuit 13 to turn on the LED. The pulse generation circuit 13 generates pulse waves at predetermined intervals and supplies them to the lighting circuit 15.

The lighting circuit 15 obtains a constant current from the constant current circuit 14 to light the LED 4. The lighting of the LED illuminates the subject, and a captured image of the subject is captured by the image sensor. It is possible to shoot still images with flash light. Further, it is possible to shoot a moving image of a moving image by causing pulsed light emission at recording frame intervals. The brightness of the subject is secured by passing a current several times higher than the steady current by pulsed light emission. By the way, if the distance to the subject is 0.5m, LV
When the brightness was 1, a good image could be taken with the white LED as the main light source (ISO sensitivity 100 equivalent).

The white LED is a type in which a blue LED is coated with yellow paint to make it look white, and R (red), G in one chip.
There are two types, a type that includes (green) and B (blue) LEDs, but either one may be used. Further, the LEDs may be embedded with red, blue, and green single color LEDs instead of the white LEDs. In such a case, the color balance can be optimized by controlling the white balance of the digital camera.

FIG. 4 is a circuit diagram showing details of the pulse generating circuit, the lighting circuit and the constant current circuit of FIG. The ON signal of the release SW that is output when the shutter button is pressed is the first and second multivibrator M1,
It is input to the pulse generation circuit 13 composed of M2. When an ON signal is input to the B terminal of the first multivibrator M1, an inverted signal is output from the Q output terminal. A predetermined pulse width T1 is created by the RC circuit. Further, the Q output of the first multivibrator M1 is input to the B terminal of the second multivibrator M2, and its Q output terminal is inverted.
A pulse interval T2 is created by the second multivibrator M2.

The pulse signal generated in this way is input transistor Tr1 and transistors Tr2, Tr3, Tr4 ... Trn which also serve as a differential circuit and an output circuit.
Input to the constant current circuit 14 and the lighting circuit 15. Since the emitter current of the transistor Tr1 becomes a predetermined value and the emitter voltage becomes constant, the transistor Tr1
A constant current flows through 3, Tr4 ... Trn.
The constant current has a magnitude that is a multiple of the number of transistors, and they flow in the LEDs (D1, D2 ... Dn), respectively.
Therefore, the brightness of the subject is the brightness of the number of LEDs that emit a constant current.

FIG. 5 is a diagram showing an example in which the strobe device according to the present invention is applied to a camera incorporated in a mobile phone.
The image pickup device module 22 is arranged above the liquid crystal screen 29 on the front side of the mobile phone 21. Three LEDs 25 are embedded around it at 120 degree intervals. The image sensor module 22 is attached to the FPC 23,
3 is connected to the main board 30 by the FPC connector 24. LCD screen 21 when shooting yourself in a dark place
It is possible to determine the composition while looking at the image and make the LED 25 emit light to take a picture. When photographing other things, the photographing lens can be directed toward the subject to emit light and photographed.

FIG. 6 is a diagram showing an example applied to a camera of a type mounted on a mobile phone. Almost round camera 36
The image pickup device module 32 is arranged at the center of, and three LEDs 35 are arranged at 120 ° intervals around the image pickup device module 32.
The connection terminal 37 is a plug side terminal of the earphone microphone, and can be inserted and connected to the receiving side of the earphone microphone terminal of the mobile phone 31. This camera can be rotated 360 degrees around the earphone / microphone terminal as an axis, and can be photographed while checking the front side or the opposite side on the liquid crystal screen 39.

[0016]

As described above, the present invention has the following effects. (1) In a digital camera (including built-in type), it is possible to realize a system in which an LED (white or single color) is used as main light to emit light. (2) Since the number of parts can be reduced and the size can be reduced, it can be built in a mobile phone. This enables cost reduction. (3) Since the cellular phone is easily affected by noise due to strobe emission, the LED system can reduce malfunctions due to noise. Since a larger amount of current is supplied than the steady-state current, a pulse light emission method is used to flow a current several times as large as the steady-state current (the number of LEDs) to ensure a predetermined subject brightness.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an embodiment of a compact strobe device according to the present invention.

FIG. 2 is a cross-sectional view in the vicinity of a taking lens of a compact strobe device according to the present invention.

FIG. 3 is a block diagram showing an embodiment of the circuit of FIG.

FIG. 4 is a circuit diagram showing details of a pulse generation circuit, a lighting circuit, and a constant current circuit of FIG.

FIG. 5 is a diagram showing an example in which the strobe device according to the present invention is applied to a camera built in a mobile phone.

FIG. 6 is a diagram showing an example in which the strobe device according to the present invention is applied to a camera that is mounted on a mobile phone.

[Explanation of symbols]

1 camera 2 Shooting lens 3 finder 4,25 LED 5 switches 6 Shutter button 7 substrate 8 Shooting lens holder 10 MPU 11 Image sensor 12 Sync signal 13 pulse generation circuit 14 constant current circuit 15 Lighting circuit 21,31 mobile phone 22,32 Image sensor module 23,33 FPC 24, 34 FPC connector 29, 39 LCD screen 30,40 Main board

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 17/18 G03B 17/18 Z H04M 1/00 H04M 1/00 U 1/02 1/02 C 1 / 21 1/21 Z 1/725 1/725 // H04N 101: 00 H04N 101: 00 F Term (reference) 2H053 CA15 CA45 2H102 AB15 BB05 CA02 5C022 AA12 AA13 AB15 AC11 AC78 CA00 5K023 AA07 BB09 HH08 MM07 5K027 AA11 BB03 BB07 HH30 MM16

Claims (5)

[Claims] 1. A still image is obtained by arranging one or more LEDs around a photographing lens of a digital camera for a mobile terminal device, performing pulsed light emission, and passing a current several times as large as a steady current to secure a subject brightness. A compact strobe device characterized by being capable of continuous shooting of the flash photography of. 2. A digital camera for a portable terminal device is provided with one or more LEDs around a photographing lens, and pulsed light emission is performed in synchronization with the number of frames of a moving image, thereby making it possible to shoot a moving image of a moving image. Small strobe device characterized by 3. A digital camera with a built-in portable terminal device or a wearable type, wherein one or more LEDs are arranged around a photographing lens to perform illumination display such as rotation display in addition to light emission photography. A compact strobe device having the above-mentioned configuration. 4. In a digital camera with a built-in portable terminal device or a wearable type, one or more LEDs are arranged in the periphery of a photographing lens to emit light for displaying elapsed time at the time of timer photographing in addition to light emission photographing. A compact strobe device characterized in that 5. The white LED or red LED,
5. The compact strobe device according to claim 1, wherein the color balance is optimized by controlling the white balance of a digital camera by using blue and green monochromatic LEDs.