JPH01193832A - Projecting device - Google Patents

Abstract

PURPOSE:To save power consumption and to prevent the shortening of the life of a xenon lamp by superposing a high current to the xenon lamp in tuning to the opening of a shutter and supplying a base current to the xenon lamp in tuning to the opening of the shutter. CONSTITUTION:A lighting circuit 4 which usually supplies the low base DC current to the xenon lamp 3 and supplies the high current to said lamp 3 so as to improve the output of light when a pulse current is superposed is provided on a projecting device which chops light from the xenon lamp 3 with a rotary shutter 60. By providing a means for generating the pulse current in synchronizing with the rotation of the shutter 60, the lighting device of the xenon lamp 3 is driven with the pulse current, so that the high current is superposed on the xenon lamp 3 in tuning to the opening of the shutter 60 and the base current is supplied to the xenon lamp 3 at the time of closing the shutter 60. Thus, the power consumption can be saved and the output of light can be improved. And also the life of the lamp can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a projection device using a xenon lamp as a light source.

(Prior Art) Generally, a projection apparatus includes a light source and a rotating shutter for flickering the light from the light source before it hits the film. The film is fed intermittently at 24 frames per second, and while the film is being scraped off, the shutter is closed and chopped, thereby preventing flickering.

By the way, the light source for projection equipment is close to a point light source.
It is known that xenon lamps are used because they have excellent color rendering properties, have a color temperature and spectrum similar to sunlight, and can instantaneously provide sufficient brightness.

Conventionally, in a projection apparatus using such a xenon lamp, the lamp is turned on continuously, and the light projected from the lamp is chopped by the rotating shutter. Additionally, the rotating shutter has two blades placed 180 degrees apart, and by rotating the shutter 24 times per second, the light from the xenon lamp is chopped 48 times per second, reducing flicker. Ta.

(Problem to be Solved by the Invention) However, in the conventional case, a xenon lamp is always lit (a constant current is supplied and the lamp is left on), and even when the rotating shutter is closed, the lamp is lit. There is a time when the lamp is lit in vain, which increases power consumption, shortens lamp life, and lowers light output efficiency.

The present invention aims to provide a projection apparatus that saves power consumption, prevents a reduction in lamp life, and improves efficiency.

Further, the present invention aims to provide a projection apparatus that can further suppress flicker and provide a high-quality screen.

[Structure of the Invention] (Means for Solving the Problems) The first aspect of the present invention is to provide a projection device that uses a xenon lamp as a light source and chops the light emitted from the xenon lamp with a rotating shutter, in which the xenon lamp is always used. A lighting circuit is provided that supplies a low base DC current to the lamp and also supplies a high current to the xenon lamp when a pulse current is superimposed to increase the light output, and the pulse current is supplied in synchronization with the rotation of the shutter. The pulse current drives the xenon lamp lighting device to superimpose a high current on the xenon lamp in synchronization with the opening of the shutter, and supplies a base current to the xenon lamp when the shutter is closed. It is characterized by being made to do.

The second aspect of the present invention is the first aspect of the invention, but
The rotary shutter is opened and closed three times or more for each frame of the film, and in synchronization with this opening and closing, a high current is superimposed on the xenon lamp when the shutter is open.

(Function) According to the first aspect of the present invention, the light output is increased by superimposing a high current on the xenon lamp in synchronization with the opening of the shutter, and the base current is supplied to the xenon lamp when the shutter is closed to reduce the output. Compared to conventional lamps where a constant high current is continuously passed through the lamp and the lamp is turned on with a constant light output, at least when the shutter is closed, a low current is passed through the lamp. As a result, power consumption can be saved, light output can be improved, and lamp life can be improved.

Further, according to the second aspect of the present invention, the rotary shutter opens and closes three or more times per frame, and in response to the opening of the shutter, a high current is supplied to the xenon lamp to cause it to emit strong light, thereby preventing flickering and Get a bright screen,
It becomes possible to realize high-quality screens.

(Example) The present invention will be described below based on a first example shown in FIGS. 1 to 4.

FIG. 1 shows a light source device 1 and a rotary shutter drive device 2 in a projection apparatus.

The light source device 1 includes a xenon lamp 3 and a lighting circuit 4 for lighting the xenon lamp 3. The lighting circuit 4 is shown in FIG. 2 and will be described.

The xenon lamp 3 is connected to a commercial AC power source via a ballast 11 and a rectifying diode 12 in series, and a first switch 14 is connected in parallel to the rectifying diode 12.

Further, the primary winding of a power transformer 15 is connected to the AC power source, and the input side of a full-wave rectifier diode bridge circuit 16 is connected to the secondary winding of this transformer 15. A smoothing capacitor 17 is connected to the output side of this full-wave rectifier diode bridge circuit 16, and this smoothing capacitor 17 includes a constant voltage diode 18 and a resistor 19.
The series circuits are connected in parallel.

A capacitor 21 is connected in parallel to the constant voltage diode 18, and a PNP type first transistor 22 is connected in series with the constant voltage diode 18 and a resistor 19, and a resistor 23.24 is connected in series to the emitter side of the first transistor 22. and is connected in parallel to the collector side of the resistor 25 via a resistor 25. In addition, capacitors 20 and 27 are connected to resistors 24 and 25, respectively.
are connected in parallel.

The base of the first transistor 22 is connected via a resistor 28 to a connection point between the constant voltage diode 18 and the resistor 19.

Further, in the series circuit of the constant voltage diode 18 and the resistor 19, NPN type second and third transistors 29 and 30 are connected.
An amplifier circuit 31 consisting of the following is connected in parallel. This amplifier circuit 31 has a second transistor 29 as a first stage, a third transistor 30 as a second stage, and
A parallel circuit of a resistor 32 and a capacitor 33 is connected to the emitter of the transistor 9, and this emitter is connected to the base of the third transistor 30. Further, the base of the second transistor 29 is connected to the base of the first transistor 22.
A resistor 34 is connected to the emitter of the third transistor 30.

A capacitor 35 is connected in parallel to the series circuit of the constant voltage diode 18 and the resistor 19, and the capacitor 35 is connected to fourth, fifth, sixth, seventh transistors 38, 37, . . . of NPN type. A discharge circuit 40 formed by connecting 38 and 39 in parallel is connected in parallel. The bases of each of the transistors 36 to 39 are connected to the emitter of the third transistor 30 of the amplifier circuit 31, respectively. Note that resistors 41, 42, 43, and 44 are connected to the emitters of each of the transistors 36 to 39, respectively.

The parallel circuit of the resistor 25 and capacitor 27 includes an NP
An N-type eighth transistor 45 is connected in parallel, and the base of this transistor 45 is connected to a movable terminal of a variable resistor 46 connected in parallel with the resistor 41.

The resistor 20 has one end, which is a connection terminal with the resistor 19, connected to one end of the xenon lamp 3 via a diode 47 and a second switch 48 in series, and the other end is connected to a third
It is connected to the other end of the xenon lamp 3 via a switch 49 .

The capacitor I7, voltage regulator diode 18, resistor 19
, 20, first transistor 22. The amplifier circuit 31, the capacitor 35, and the discharge circuit 40 constitute a pulse current superimposition circuit.

Each of the switches 14, 48, and 49 is a switch control circuit 5.
6, the first switch 4 is closed before the lamp 3 is lit, and the second and third switches 48 and 49 are opened, and after the lamp is lit, the switch control circuit 4 is closed. Based on the command from 56, the first switch 4 is opened and at the same time the second and third switches 48.4 are opened.
9 is designed to close.

Further, the primary winding of a power transformer 50 is connected to the AC IS source, the input side of a full-wave rectifying diode bridge circuit 51 is connected to the secondary winding of this transformer 50, and the output side of this diode bridge circuit 51 is connected to the secondary winding of this transformer 50. A series circuit consisting of a constant voltage diode 52 and a resistor 53 is connected to the circuit. A series circuit of a resistor 54 and a variable resistor 55 is connected in parallel to this resistor 53. Further, the variable resistor 55 has a connecting terminal between its movable terminal and the resistor 53 connected in parallel to the series circuit of the base and emitter of the first transistor 22, the resistor 23, and the resistor 24.

In the lighting device configured as above, as shown in FIG.
A pulse m& is superimposed on the xenon lamp as shown in b).

That is, when current is first applied to the lighting circuit, the ballast 11
The xenon lamp is started and lit via the first switch 14, and in this state, the xenon lamp 3 is supplied with a predetermined base current 1 win via the ballast 11 and the first switch 14.

Then, at a timing to be described later, the first switch 14 is opened by a command signal from the switch control circuit 56, and the second switch 14 is opened.
When the third switch 48, 49 is closed, a pulse current is supplied from the pulse current superimposition circuit to the xenon lamp 3, and this pulse current is superimposed on the supplied base current to generate the maximum current at that time. It becomes I l1ax.

In addition, the maximum current lll1 for the base current 1 min
The ratio of aX is 1.4≦I max / I n+In≦
6. Specifically, I wax is 22ASIa+In is 7.
It is set to 5A. Also, the ratio of the energization time t of the superimposed pulse to the period T is 0.2≦t/T≦0
．． 7. In this embodiment, it is set to t/T-0.5.

On the other hand, the rotary shutter drive device 2 shown in FIG. 1 will be explained.

60 is a rotating shutter, and the rotation of the motor 61 is the gear 6.
2.133.64, and thus this rotary shutter 60 is rotated at a constant period.

Note that the motor 61 normally operates to take up the film 65.
6 through an intermittent wheel drive mechanism (not shown), a separate motor may be used.

In this embodiment, the rotary shutter 60 has two blades as shown in FIG. 3, and this rotary shutter 60 chops the light emitted from the xenon lamp 3 toward the film 65. do.

Here, since the shutter 60 has two blades, it opens and closes twice in one rotation, so the opening and closing cycle in one rotation is 2 times.
If T, the period of one opening/closing operation of the shutter 60 is T, the opening time in this period T is TI, and the opening time is T2. That is, the opening/closing timing of this shutter GO is as shown in FIG. 4(a).

In the rotary shutter drive device 2, an encoder 67 is connected to a gear 63, and the encoder 67 is provided to rotate at the same rotation angle as the rotary shutter 60, or at a rotation angle that is a fraction of an integer. , a pulse signal corresponding to the opening/closing operation of the rotary shutter 60 is emitted. That is, it converts a rotation angle into an electric pulse.

The pulse signal emitted from the encoder 67 is connected to the switch control circuit 56 of the lighting circuit 4 via a phase matching circuit 70, a waveform shaping circuit 71, a counting circuit 72, and a pulse width regulation circuit 73.

The phase matching circuit 70 corrects a timing difference between the encoder 67, which converts the rotation angle into an electric pulse, and the rotation angle of the rotary shutter 60. That is, in conventional projectors, the rotary shutter is attached to the rotary drive shaft so that the rotation angle can be adjusted using screws, without using means such as keys or pins for fixing the shutter. This is because it is important that the rotary shutter 60 accurately interlocks with the intermittent wheel drive mechanism that feeds the film 65 intermittently.
This is to enable adjustment of the intermittent wheel drive mechanism. Therefore, for the rotary shutter 6o having such a structure,
When the encoder 67 is connected to the gear 63, when the rotary shutter 60 is adjusted with respect to the intermittent wheel drive mechanism, the opening/closing timing by the rotary shutter 60 and the encoder 67 are adjusted.
Therefore, the pulse generation timing may be shifted, and such angular phase is corrected by the phase matching circuit 70.

The waveform shaping circuit 71 corrects the distortion of the pulse waveform and generates a correct rectangular waveform.

The counting circuit 72 is used when the number of openings and closings of the rotary shutter 60 and the number of pulses generated by the encoder 67 are not the same but have an integer ratio relationship, or when multiple high currents are superimposed for one opening and closing of the rotary shutter 6o. It is converted to generate the required number of pulses.

The pulse width regulation circuit 73 is for adjusting the superimposition duration time.

The operation of the embodiment with such a configuration will be explained.

The film 65 is intermittently fed by the rotation of the motor 61 via an intermittent wheel drive mechanism (not shown), and at the same time the motor 6
1 rotates the rotary shutter co via gears 02.63.84.

The film 65 is intermittently fed at 24 frames per second, and at this time the rotary shutter 60 rotates 24 times per second.Since this rotary shutter has two blades, it blocks the light emitted from the lamp 48 times per second. In other words, chopping is performed twice for each frame of film.

In synchronization with the rotation of the rotary shutter 60, the encoder 67
is rotated, and this encoder 67 generates a pulse signal 48 times per second.

This pulse signal is transmitted to a phase matching circuit 70, a waveform shaping circuit 7
L vF, number circuit 72) is sent to the lighting circuit 4 via the pulse width regulation circuit 73. During this time, the phase matching circuit 70
corrects the gap between the opening/closing timing of the rotary shutter 60 and the pulse generation timing of the encoder 67, the waveform shaping circuit 71 corrects the collapse of the pulse waveform, and the counting circuit 72 adjusts the number of openings/closings of the rotary shutter 60 and the pulse generation of the encoder 67. In this embodiment, the number of openings and closings of the rotary shutter 60 and the number of pulses generated by the encoder 67 are the same, so no special adjustment is required. ), the pulse width regulating circuit 73 adjusts the superimposition duration time.

Such a pulse signal is sent to the lighting circuit 4, and in this lighting circuit 4, when the above-mentioned pulse signal is given, the switch control A1 circuit 56 outputs a command signal to open the switch 14 and close the switches 48 and 49. Therefore, as shown in FIG. 4(b), a high current of 1 wa is applied to the xenon lamp 3.
Flow x.

When a high current of 1118X is passed through the xenon lamp 3, it emits strong light, and this state is essentially the same as lighting up. Then, the high current 111a is applied to the xenon lamp 3.
When X is no longer supplied, only the base current 11n is supplied to the xenon lamp 3, and in this case, the light is dimmed.

When the rotary shutter 60 is closed, at T2, a base current of 1 min is applied to the lamp 3 to dim the lamp, and when the shutter 6o is open, a high current of 1 ff1aX is applied to the TI. It will emit strong light.

For this reason, compared to conventional lamps in which a constant high current is continuously passed through the lamp and the lamp is left on, the current is low, at least when the shutter is closed. Just play Kffl,
Power consumption can be saved, light output can be improved, and lamp life can be extended.

The following table shows 3 xenon lamps with an average lamp power of 350W.
The results of comparing the conventional example and the present invention when used in combination with the rotary shutter 60 are shown.

The lamp power of the present invention can be as high as 539 W when the shutter is open, and the total effective light output can be increased by 86% to 186 when the conventional example is 100.

In the above embodiment, a case has been described in which the pulse current is superimposed once m in one shirt opening/closing operation, but a plurality of pulse currents may be superimposed during one shirt opening/closing operation. An example of this is shown in FIG.

That is, in this example, the shutter 60 is
When the shutter is open in synchronization with the opening/closing operation of the shutter, a superimposed pulse with a time width of t- is supplied twice.

In this case, the cumulative time t during which the high current flows is 2t-,
If this time satisfies the condition of 0.2≦t/T≦0.7, the effective light output can be made sufficient and the screen can be irradiated with sufficient light. Also, the high current I l1ax supplied to the xenon lamp 3
It is effective in improving flickering because it is repeated in a quick cycle.

Furthermore, it is found that it is more effective to prevent flicker if the time when the high current Ill1ax is applied and the light output is large is approximately similar to the time when the base current 1 min is applied and the light is dimmed. Confirmed.

Further, the present invention may be as shown in FIGS. 6 and 7.

That is, in the case of the embodiments shown in FIGS. 1 to 4, 6 rotary shutters are used for each frame of the film.
0 was designed to open and close twice, but as shown in FIG. good.

When the rotary shutter 80 opens and closes three times per frame, a pulse is given to the xenon lamp 3 three times in accordance with the opening of the shutter, and a high current is supplied to cause strong light emission.

The rotary shutter is used to prevent flickering when the film moves intermittently, and conventionally it opens and closes twice per frame, or 48 times per second. However, with something like this, if the screen gets brighter, flickering can be felt.

For this reason, it is effective to open and close the door three or more times, but if the light source is a constant light amount as in the past, the number of times the light is interrupted is large, so the brightness is extremely reduced, making it impractical.

As in the present invention, the base current 1 akin has a high current I
In the case of the type that lights up by superimposing n + ax, the light output improves, eliminating the lack of light. Therefore, by setting the light intensity to increase when the shutter is opened, flickering can be prevented and a bright screen can be obtained. , it becomes possible to realize a so-called high-quality screen.

It should be noted that if the encoder 67 is used as a means for generating pulse signals in accordance with the opening and closing timings of the rotary shutters 80, 80, there is an advantage that the present invention can be implemented in existing projectors without requiring major changes. However, the means for generating a pulse signal in accordance with the opening/closing timing of the rotary shutter Go, 80 is not limited to the encoder 67, and the rotation angle of the rotary shutter Go, 80 can be directly detected optically, magnetically, or electrically. You can do it like this.

In addition, this does not apply to the phase matching circuit 70, waveform shaping circuit 71, counting circuit 72) pulse width regulation circuit 73, etc.
These circuits may be selected and used as necessary.

[Effects of the Invention] As explained above, according to the first aspect of the present invention, the light output is increased by superimposing a high current on the xenon lamp in synchronization with the opening of the shutter, and the base current is applied to the xenon lamp when the shutter is closed. Since the light is dimmed by supplying light to the lamp, compared to the conventional method where a constant high current is continuously passed through the lamp and the lamp is turned on with a constant light output, at least the shutter is closed. Since only a low current needs to flow at times, it is possible to save power consumption, improve light output, and extend lamp life.

Further, according to the second aspect of the present invention, the rotary shutter opens and closes three or more times per frame, and in response to the opening of the shutter, a high current is supplied to the xenon lamp to cause it to emit strong light, thereby preventing flickering and Get a bright screen,
It becomes possible to realize high-quality screens.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a configuration diagram explaining a light source device of a projection device, FIG. 2 is a lighting circuit diagram, and FIG. 3 is a front view of a rotary shutter. Figure 4 is a timing chart explaining the film feeding operation, shutter opening/closing operation, and xenon lamp dimming operation, and Fig. 5 is a film feeding operation and shutter opening/closing operation showing another embodiment of the present invention. 6 and 7 show still other embodiments of the present invention, FIG. 6 is a front view of the rotary shutter, and FIG. 7 is a film feeding operation. FIG. 3 is a timing diagram illustrating the opening/closing operation of the shutter and the dimming operation of the xenon lamp. 1... Light source device, 2... Rotating shutter drive device, 3
...Xenon lamp, 4...Lighting circuit, 60.80
...Rotating shutter, 61...Motor, 65...Film, 67...Encoder. Applicant's agent Patent attorney Takehiko Suzue 1 frame □ Figure 4 1 i″ dimension: 1 Figure 5

Claims (2)

[Claims] (1) Using a xenon lamp as a light source,
In a projection device that chops the light emitted from the xenon lamp using a rotating shutter, a low base DC current is normally supplied to the xenon lamp, and when a pulse current is superimposed, a high current is supplied to the xenon lamp to output light. a lighting circuit for increasing the temperature, and a means for generating a pulse current in synchronization with the rotation of the shutter;
This pulse current is applied to the xenon lamp lighting device to superimpose a high current on the xenon lamp in synchronization with the opening of the shutter, and a base current is caused to flow through the xenon lamp when the shutter is closed. projection device. (2) In the projection apparatus according to claim 1, the rotary shutter opens and closes three or more times for each frame of the film, and in synchronization with this opening and closing, when the shutter is open, a high current is applied to the xenon lamp. A projection device characterized by superimposing images.