JP3154191B2 - LCD projector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector having a plurality of light sources.

[0002]

2. Description of the Related Art A liquid crystal projector using a liquid crystal panel is constructed as shown in FIG. FIG. 1 shows a conceptual diagram of the liquid crystal panel, in which a light source (eg, a halogen lamp) 20 is condensed by a condensing lens 11 and converted into parallel light. 12 to form a color image, for example.
After that, the screen 1 is enlarged by the projection lens 13.
4 to obtain an enlarged color image.

[0003]

As a light source 20 used in such a liquid crystal projector 10, a halogen lamp or the like is usually used, but this light source 20 has a relatively short life. Therefore, if the frequency of use is high, the light source 2
It is necessary to frequently perform the replacement work of 0, and the replacement work is troublesome.

Therefore, the present invention has been made to solve such a conventional problem, and proposes a liquid crystal projector capable of extending the substantial life of the light source and reducing the number of replacement operations.

[0005]

In order to solve the above-mentioned problems, according to the present invention, in a liquid crystal projector,
Light in which multiple light sources are provided at approximately the same distance from the center of rotation
A light source holder plate and a light source holder plate provided at a rotation center of the light source holder plate.
A shaft portion, and a substrate rotatably supporting the shaft portion,
The light source holder plate provided on the substrate is rotationally driven.
Driving means, and a plurality of driving means provided on the light source holder plate.
Of the light sources, the optical axis on the light source side of the liquid crystal projector is
Energization switching means for switching only the facing light source to energize
And a control means for controlling rotation of the driving means and lighting of the light source.
And a drive unit for driving the liquid crystal projector.
Each time the light source is turned on and off, the light source holder plate is rotated.
Is controlled by the control means so that the light sources are sequentially turned on.
It is characterized by being performed . In addition, the present invention
In a liquid crystal projector, multiple light sources
Light source holder plate provided at approximately the same distance from the center of rotation
And a shaft provided at the center of rotation of the light source holder plate
And a substrate rotatably supporting the shaft, and
Driving means provided for rotating and driving the light source holder plate
And a plurality of light sources provided on the light source holder plate.
Of which, the light facing the optical axis on the light source side of the liquid crystal projector
Power supply switching means for switching to supply power only to the power source;
A light intensity sensor for detecting the light intensity of the light source facing the optical axis;
Control means for controlling the rotation of the driving means and the lighting of the light source.
The light intensity of the light source during operation of the light intensity sensor is equal to or less than a predetermined value.
When it is detected that the light source is below,
Rotate the holder plate and turn on the next light source.
Characterized by being controlled by control means.
You.

[0006]

As shown in FIG. 1, a plurality of light sources 20a, 20b,... Are prepared as the light source 20, and these are switched and used when necessary. Therefore, the substantial life of the light source 20 is increased by the number of mounted light sources, and the light source replacement work is reduced accordingly.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where an example of a liquid crystal projector according to the present invention is applied to a color liquid crystal projector will be described in detail with reference to the drawings.

FIG. 1 shows an example of a color liquid crystal projector 10 using three liquid crystal panels. Light emitted from a light source 20 (shown by a dashed line) is dichroic after its optical path is changed by a mirror (reflecting mirror) 21. Mirror 24
Thus, in this example, the red primary color light R is reflected. The red primary color light R is supplied to the liquid crystal panel 30 via the mirror 22 as its light source (red light source). The liquid crystal panel 30 is supplied with a red primary color signal, whereby a red color separation image is obtained.

Similarly, the blue primary color light B is separated by the dichroic mirror 25, and the liquid crystal panel 31 is irradiated with a blue light source. Since a blue primary color signal is supplied to the liquid crystal panel 31, a blue color separation image is obtained from the liquid crystal panel 31. And the dichroic mirror 25
The green primary color light G transmitted through the liquid crystal panel 32 is radiated to the liquid crystal panel 32 as a light source. Since the green primary color signal is supplied to the liquid crystal panel 32, a green color separation image is obtained from this signal. The green color separation image is supplied to the dichroic mirror 27 via the mirror 23 together with the other color separation images (R and B). After the color separation images are combined, the light is condensed on the condenser lens 11.

The light source 20 comprises a plurality of light sources. In this example, as shown in FIG. 2, four light sources 20a to 20d are provided, and each of them is sequentially switched by a light source switching device 40.

FIG. 2 shows a specific example of the light source switching device 40. The four light sources 20a to 20d are arranged and fixed at 90 ° intervals on a disk-shaped lamp holder 41 as shown in FIG. Spherical reflecting plates 42a to 42d are arranged on each of them so that light is reflected in one direction. The lamp holder 41 is rotatably fixed to a circuit board (or a panel of a projector) 45, and a knob 49 is attached to a rotating shaft 41 a projecting in one direction via a spring 50.

Since the lamp holder 41 is pressed against the circuit board 45 by the spring 50, free rotation of the lamp holder 41 is prevented.

Circuit board 45 facing lamp holder 41
A concave portion 43a for click motion is formed on the plate surface. In the example of FIG. 2, a total of eight recesses 4 are formed on the same circumference.
3a to 43h are formed at the same angle, and only one positioning pin 46 as shown in FIG.

The positioning pin 46 and the positioning pin 4
6, eight recesses 4 formed on the same circumference as this example.
A click motion is applied to the lamp holder 41 by the springs 3a to 43h and the spring 50 described above. That is, if the knob 49 is pressed, the rotation of the lamp holder 41 becomes free, and the lamp holder 41 can be rotated in any of the clockwise direction and the counterclockwise direction. By contacting 43g (43h to 43f), the rotation stop position of the light source 20 can always be fixed to the state shown in FIG. The number of positioning recesses may be four.

A circuit contact 47 is formed on a part of the circuit board 45, and the lamp contacts 41 are provided at positions corresponding to the number of the individual light sources 20a to 20d so as to face the circuit contact 47. Is attached, light source 2
0 is supplied.

In the case where the light source switching device 40 is configured as described above, when the user wants to use another light source, he can turn the knob 49 to freely select from four light sources 20 he wants to use. When deterioration is running out,
Alternatively, when the light source 20 is cut off, the next new light source can be selected and used. Thus, the color image can be enlarged and projected by the new light source without replacing the light source.

FIG. 4 shows another example of the light source switching device 40. In this embodiment, a push button type is used, and a push button 5 having an operation lever 53b on the projector panel 52 side is used.
3 are arranged, and the gear 55 rotates by a predetermined angular range in connection with its operation. The gear 55 is formed in a fan shape so as to rotate about the fulcrum 54, and has a tooth 55a at its tip.
Is formed, and the other end portion 55b is a contact portion with the push button 53. A return spring 53a is attached between the push button 53 and the panel 52. A return spring 56 is also attached to the gear 55.

A drive gear 51, which rotates integrally with the lamp holder 41, is attached to the lamp holder 41 as shown in FIG.
As shown in FIG. 4, the gear 55 is partially engaged with the gear 55. A plurality of recesses 41a are formed on the outer peripheral surface of the lamp holder 51,
A ratchet 58 having a return spring 59 is arranged to face the concave portion 41a.

Therefore, as shown in FIG.
When the button 55 is pressed, the gear 55 rotates counterclockwise, and the driving gear 51 rotates clockwise, in this example, 1/8 of a turn. Therefore, when the push button 53 is operated twice, the light source is moved to the zenith position. A light source 20d is located instead of 20a.

One operation of the push button 53 allows the lamp holder 4
The stroke amount of the push button 53, the rotation angle of the gear 55, and the like may be selected so that 1 rotates by 1/4.

After one-quarter rotation, the rotational position is fixed by the ratchet 58, and the push button 53 and the gear 55 return to their original positions shown in FIG. 4 by the action of the return springs 53a and 56 provided respectively. I do.

In each of the embodiments shown in FIGS. 2 and 4, the operator manually switches the light source. However, the light source can be automatically switched.

FIG. 7 shows an example of this case. In this example, automatic switching is performed in connection with turning on and off the switch 61 of the apparatus power supply. That is, the power switch 6
1 is detected by a detection circuit 62, and the detection signal is supplied to a control circuit 63 to control a drive source 64 for the light source switching device 40.

The driving source 64 is a lamp holder 41 shown in FIG.
When the power switch 61 is turned on, power is supplied to the selected light source 20, and when the power switch 61 is turned off, a drive signal is output from the control circuit 63 by a detection signal that detects this. Is done. This drive signal causes the lamp holder 41 to make a quarter turn. The same applies to the embodiment of FIG.

As described above, the next light source 20 is automatically selected in sequence when the power switch 61 is turned off.

In this case, the next light source is selected irrespective of the degree of deterioration of the light source 20 or whether it is cut off.
If 0 is significantly deteriorated or the light source 20 is turned off, the power supply switch 61 is switched on and off twice to switch to the next new light source 20, so that there is no particular inconvenience even in the sequential switching method.

The light source 20 is significantly deteriorated or the light source 2
When 0 has expired, the next light source may be selected without selecting that light source. In that case, as shown in FIG. 8, a sensor 69 for detecting the light amount, heat generation of the light source, current to the light source, and the like is provided, and these are supplied to a detection circuit 70 to generate a corresponding detection signal.

The detection signal is supplied to the control circuit 71 to detect whether or not the light amount is equal to or less than the reference value. If the detection signal is equal to or less than the reference value, a drive signal is generated.
The next light source is selected by being driven by / 4 rotation.

Similarly, when the heat generation of the light source is abnormally high, the driving source 64 is controlled based on the output of the heat detection sensor to stop using the light source. When the current to the light source is zero, the light source is turned off, and the next light source is selected in this case as well.

FIG. 9 shows a specific example of the main part of the light source switching device 40 employing the current detection method. In this example, three light sources 20a, 20b,
20c is illustrated. Each light source 20a, 20b, 2
Relays 75a, 75b, 75c are connected in series to 0c, and switches (relay switches) SWa, SWb, SW operated by these relays 75a, 75b, 75c are connected.
c is connected in series to the power supply path. In this case, the switches SWa, SWb, and SWc are connected such that the power path of the light sources 20b and 20c is controlled by the switch SWa, and the power path of the light source 20c is controlled by the switch SWb.

In the initial state, it is assumed that all the power supply paths are closed as shown in the figure. In this state, the power supply supplies the relay 75a first, and then the relay 75a.
It is assumed that the priorities are set so that b and 75c operate sequentially.

In such a case, the relay 75a operates by the first energization, and the switch SWa is opened. Then, the power supply to the light sources 20b and 20c is cut off. Next, when the light source 20a is cut off due to life or breakage, the relay 75b operates first, and in this case, only the light source 20b is energized. When both the light sources 20a and 20b are cut off, the relay 7
5c operates, and the light source 20c is energized.

As described above, the control is such that only one light source is energized. Position control is also performed so that the used light source always comes to a fixed position.

When a plurality of light sources are used, it is very convenient to know the number of light sources that can be used and the light source (light source number) currently in use. FIG. 10 is a flow chart showing an example for realizing the display device 80 for responding to such a request. As a premise, a unique number is assigned to each light source, and the number can be checked. It is assumed that

In the display flowchart, the light source being prepared is checked (step 81), and the number of the light source currently used is checked (step 8).
2). The outputs of both are used to detect the used light source and the usable light source (step 83), and the output displays the number of the used light source and the number of the usable light source (step 84). .

A selection is made as to which light source is to be used next from the number of the light source being prepared and the number of the light source being used (step 85), and a switching process for the selected light source is performed (step 86). . This switching signal is supplied to step 82 and used as a signal for the process of detecting the currently used light source.

By performing the above-described processing, the operator can visually confirm the number of the light source currently used and the number of light sources that can be used from now on. Therefore, the present invention is particularly suitable for a case where the light source is manually switched. is there.

The number of light sources used is not limited.

[0039]

As described above, in the liquid crystal projector according to the present invention , the plurality of light sources are at substantially equal distances from the center of rotation.
Light source holder plate provided in the, light source holder plate
A shaft provided at the center of rotation; and a rotatably supported shaft.
A light source holder plate provided on the substrate
A driving means for driving and rotating the light source holder plate
Of the plurality of light sources provided, the light of the liquid crystal projector
Switch to energize only the light source facing the optical axis on the source side
Power supply switching means, and rotation of the driving means and lighting of the light source.
Control means for controlling the liquid crystal display.
Each time the power of the projector is turned on and off, the light source holder plate
Is controlled so that a plurality of light sources are sequentially turned on.
It is controlled by means. Also,
In the liquid crystal projector according to the invention, the plurality of light sources are rotated.
A light source holder plate provided at an approximately equal distance from the center;
A shaft provided at the center of rotation of the light source holder plate;
A substrate rotatably supporting the shaft portion; and a substrate provided on the substrate.
Driving means for driving the light source holder plate to rotate,
Of the plurality of light sources provided on the light source holder plate,
Only the light source facing the optical axis on the light source side of the liquid crystal projector
Energization switching means for switching to energize;
A light amount sensor for detecting a light amount of a light source facing the light source;
Control means for controlling the rotation of the step and the lighting of the light source;
The light intensity of the light source during operation of the light intensity sensor is equal to or less than a predetermined value
When detecting that the light source holder
Said control means so that the plate is rotated and the next light source is turned on
Is controlled by the

According to this, it is possible to extend the life of the light source substantially by the number of light sources, and to reduce the troublesome work such as the replacement work of the light source. Further, it is very convenient for the user if automatic switching of the light source and display of the used light source or the number of the usable light source can be performed. Also, the light intensity of the light source when the light intensity sensor is operating
When the driving means detects that the
Rotate the source holder plate so that the next light source is turned on.
Control means, so that the light intensity of the light source
Automatically switches to the next light source when the value falls below the set value
The light intensity of the light source has dropped below a certain value during use.
Therefore, it is possible to reliably prevent the light source from being cut off.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part showing an example of a liquid crystal projector according to the present invention.

FIG. 2 is a plan view of an example of a light source switching device.

FIG. 3 is a side sectional view thereof.

FIG. 4 is a side sectional view showing another example of the light source switching device.

FIG. 5 is a plan view thereof.

FIG. 6 is a diagram showing another operation state of FIG. 4;

FIG. 7 is a system diagram showing another example of the liquid crystal projector.

FIG. 8 is a system diagram showing another example of the liquid crystal projector.

FIG. 9 is a system diagram of a main part showing another example of the light source switching device.

FIG. 10 is a diagram showing an example of a display processing flowchart.

FIG. 11 is an explanatory diagram of a liquid crystal projector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Liquid crystal projector 20 (20a-20d) Light source 21,22,23 Mirror 24,25,26,27 Dichroic mirror 30,31,32 Liquid crystal panel 11 Condensing lens 14 Screen 40 Light source switching device 42a-42d Reflection plate 49 Knob

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/13

Claims (2)

(57) [Claims] In a liquid crystal projector, a plurality of light sources are provided at substantially equal distances from a center of rotation.
A source holder plate, a shaft portion provided at the center of rotation of the light source holder plate, a substrate rotatably supporting the shaft portion, and a rotation drive of the light source holder plate provided on the substrate.
Driving means, among a plurality of light sources provided on the light source holder plate,
The light source facing the optical axis on the light source side of the liquid crystal projector
Energization switching means for switching to energize only, control means for controlling the rotation of the driving means and lighting of the light source;
Wherein the drive means is power-off of the liquid crystal projector
Each time the light source holder plate is rotated, a plurality of light sources
A liquid crystal projector controlled by the control means so as to be turned on . 2. A liquid crystal projector in which a plurality of light sources are provided at substantially equal distances from a center of rotation.
A source holder plate, a shaft portion provided at the center of rotation of the light source holder plate, a substrate rotatably supporting the shaft portion, and a rotation drive of the light source holder plate provided on the substrate.
Driving means, among a plurality of light sources provided on the light source holder plate,
The light source facing the optical axis on the light source side of the liquid crystal projector
Energization switching means for switching only the energization and a light quantity sensor for detecting the quantity of light of a light source facing the optical axis
And control means for controlling rotation of the driving means and lighting of the light source;
The provided, der intensity of the light source in the light amount sensor operation is equal to or smaller than a predetermined value
When the driving means detects that the light source holder
The control panel is rotated so that the next light source is turned on.
Liquid crystal project characterized by being controlled by a step
Ta.