JP2000147659A - Projection type projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type projector with which the deterioration of the light emission luminance of a light source is accurately measured and an exchange timing is definitely recognized. SOLUTION: This projection type projector is constituted of a video signal processing part 30, a pattern generating part 32 driven by synchronizing with a synchronizing signal supplied to the video signal processing part and generating a luminance measuring pattern signal, a signal synthesizing part 34 by which a video signal and the luminance measuring pattern signal are synthesized, a video projecting part 40 including a projection light source to which a synthesized signal is supplied, a luminance measuring part 60 for measuring the luminance of a luminance measuring pattern projected on a screen 18 and a luminance discriminating part 70, to which a luminance signal measured by the luminance measuring part is supplied. The screen luminance of a pattern projected on the screen is measured, and when a measured luminance level is lower than a reference value, the exchange of the projection light source is instructed. Since the screen luminance is made equivalent to a light emission luminance level at the center part of the light source, the luminance of the light source is more accurately measured by measuring the screen luminance, so that the deterioration of luminance is accurately determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a projection type projector. Specifically, by measuring the brightness level of the brightness measurement pattern projected on the screen,
It is possible to accurately determine when to replace a projection light source used to project an image on a screen.

[0002]

2. Description of the Related Art A projection type projector using a two-dimensional liquid crystal element is known. FIG. 5 shows the outline of the two-dimensional liquid crystal element 14 functioning as a shutter element.
The liquid crystal element 14 is switched by a video signal supplied to the terminal 12, and the video (color video or the like) is projected on a screen 18 via the optical system 16. On the back of the liquid crystal element 14, the liquid crystal element 1
A projection light source 20 for projecting the image obtained in 4 on the screen 18 is provided. The light source 20 is housed inside a bowl-shaped reflector 22.

[0003]

As a well-known projection light source 20, a metal halide lamp, which is a kind of mercury lamp, is often used in order to obtain a predetermined screen luminance. The light emission luminance of the light source 20 such as a metal halide lamp gradually decreases after a certain operating time. If the light emission luminance is reduced to some extent, sufficient screen luminance cannot be obtained, so that the light source 20 needs to be replaced.

Normally, the screen luminance is １ ／ of the initial luminance.
When it drops to a lower level, the light source is replaced. It is said that the operating time in which the brightness is reduced to half of that when the battery is used continuously is about 3000 hours. However, the brightness reduction time greatly varies depending on the light source. One light source is 3000 hours, while another is 500 hours.
It may be 0 hours.

For this reason, when the replacement time of the light source 20 is determined based on the continuous operation time, it is necessary to replace the light source 20 in accordance with the light source having the shortest life. In this case, since it is necessary to replace even the light source whose life has not expired, it is extremely wasteful.

In consideration of the above, conventionally, the light source 2
Means for directly measuring the emission luminance of 0 is taken. In FIG. 5, the optical sensor 24 is arranged on the optical path of the light source 20.
As another example, in FIG. 6, a half mirror 26 is placed on the optical path, and the reflected light is detected by an optical sensor 24, or as shown in FIG.
In some cases, the intensity of light leaking from the light source 2 is measured by the optical sensor 24.

However, in the case of FIG. 5, since the optical sensor 24 is disposed directly on the optical path, the optical sensor is projected as a shadow on the screen 18 and a part of the image is erased. It is not a simple means.

In the example of FIG. 6, although there is no problem as in FIG. 5, since the light is guided to the optical sensor 24 using the half mirror 26, a light loss occurs, and the light emission luminance of the light source 20 is accurately measured. Can not. For this reason, there is a possibility that the replacement time of the light source 20 may be overlooked.

In the example of FIG. 7, the light emission luminance of the light source 20 is not directly measured. Since the decrease in the light amount at the center of the light source 20 is not proportional to the decrease in the light amount of the leaked light, the decrease in the emission luminance of the light source 20 cannot be accurately measured.

In view of the above, the present invention has been made to solve such a conventional problem, and proposes a projection type projector capable of accurately measuring a decrease in light emission luminance of a light source and accurately ascertaining a replacement time. is there.

[0011]

According to a first aspect of the present invention, there is provided a projection type projector, comprising: a video signal processing unit; and a synchronization signal supplied to the video signal processing unit. Includes a pattern generation unit that generates a luminance measurement pattern signal that is driven in synchronization, a signal synthesis unit that synthesizes the video signal and the luminance measurement pattern signal, and a projection light source to which the synthesized signal is supplied. It is composed of an image projection unit, a luminance measurement unit that measures the luminance of the luminance measurement pattern projected on the screen, and a luminance determination unit to which a luminance signal measured by the luminance measurement unit is supplied, and the luminance is less than a reference value. At the time of the measured luminance level, the exchange of the projection light source is instructed.

According to the present invention, a luminance measurement pattern for measuring the luminance of the light source is projected on a screen via the projection light from the light source, and the luminance of the pattern is detected by the optical sensor. The detected luminance level is compared with a reference value on the control unit side, and a reference value (a value at which the generated luminance is 例 え ば, for example)
When the value falls below the predetermined value, an instruction to replace the light source is issued, and based on the instruction, the display is lit, a buzzer is driven, and the replacement is prompted.

Since the specific pattern is projected on the screen using the light from the light source, it is equivalent to a measurement of the emission luminance itself at the center of the light source. As a result, the emission luminance can be accurately measured.

[0014]

Next, an embodiment of a projection type projector according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a system diagram of a projection type projector 10 according to the present invention, in which a video signal processing unit 30 and a luminance measuring pattern driven in synchronization with synchronization signals HD and VD supplied to the video signal processing unit 30 are shown. A signal generating unit 32 for generating a signal; a signal synthesizing unit 34 for synthesizing the video signal and the luminance measuring pattern signal; an image projecting unit 40 including a projection light source to which the synthesized signal is supplied;
A luminance measuring unit 60 that measures the luminance of the luminance measuring pattern PT projected on the display unit, and a luminance determining unit 70 to which the luminance signal measured by the luminance measuring unit 60 is supplied. At the level, the replacement of the projection light source 20 is instructed.

A color video signal to be projected on a screen 18 is supplied to a terminal 12, and this is a video signal processing unit (video processor) 30 which is a signal form suitable for shutter driving a video display element (such as a two-dimensional liquid crystal element). Is converted to In this example, since the video projection unit 40 employs a three-primary-color driving method, the image is converted into a three-primary-color signal. The three primary color signals processed by the video signal processing unit 30 are output to the signal synthesis unit 34.
Supplied to The horizontal and vertical drive signals H which are synchronization signals included in the video signal supplied to the video signal processing unit 30
D and VD are supplied to the pattern generator 32. The pattern generator 32 is for generating a pattern PT for measuring the light emission luminance of the projection light source 20 in synchronization with the horizontal and vertical drive signals HD and VD, as described later.

The luminance measurement pattern PT can take any shape, but is preferably a rectangular pattern PT as shown in FIG. 3 from the viewpoint of pattern extraction and the like. In the following description, the pattern is an all-white pattern, but the three primary colors (R,
G, B), a pattern having a specific color can be used as a luminance measurement pattern.

This pattern signal is supplied to a signal synthesizing section 34 and is synthesized with the three primary color signals as necessary, or a switching process is performed (hereinafter simply referred to as a synthesizing process). The synthesized signal is supplied to the video projection unit 40.

The image projection section 40 has a projection light source 20, and the projection light is guided to a drive element 42R used as a red image shutter element via a dichroic mirror 46a and a prism 48. As the projection light source 20, a metal halide lamp or the like, which is a kind of a mercury lamp as described above, can be used. As the driving element 42R, a transmission type two-dimensional display element, for example, a liquid crystal element (LCD) is used, and a red signal (including a pattern signal) is supplied thereto via a driver 44.

Similarly, the green projection light obtained through the dichroic mirror 46b is guided to a driving element 42G using an LCD driven by a green signal. Further, the blue projection light split by the dichroic mirror 46c is guided via a mirror 46d to a driving element 42B using an LCD driven by a blue signal.

These three driving elements 42R, 42G, 4
The color separation image obtained by driving 2B is synthesized by the synthesis prism 50, and the synthesized color image is projected on the screen 18 via the optical system 52.

The image luminance (screen luminance) of the screen 18 is changed by the projection light transmitted through the three drive elements 42R, 42G, 42B. The screen luminance depends on the light emission luminance of the projection light source 20.

As shown in FIG. 2A, on the screen 18, a pattern PT for measuring luminance is displayed in addition to the original image SM based on the image signal. The timing for displaying the pattern PT may be a fixed period immediately after the power is turned on and a video display period. In the former case, since the power is turned on immediately, it is better to display the pattern PT in a state where the video is cut off. This is because there is no need to display an image in such a time zone. In this case, the pattern PT is placed at an arbitrary position on the screen 18, for example, at a substantially central portion of the screen 18 as shown in FIG. 2B.
You can project in sync with.

In the latter case, the pattern PT is displayed at a position that does not obstruct the image SM, for example, at a part of the four corners (the lower left corner in the figure) at a small size. The size is preferably about 1 to 3 cm square.

The pattern P projected on the screen 18
T is measured by the luminance measuring unit 60. Luminance measuring unit 6
Reference numeral 0 denotes an optical system 62 for taking out the pattern PT at the center as shown in the figure, and an optical sensor 64 for converting the luminance (white level or specific color level) of the pattern guided to the optical system 62 into an electric signal. Is done.

The measurement signal from the optical sensor 64 is supplied to the amplifier 6
After that, it is supplied to the luminance determination unit 70. Brightness determination unit 70
Is composed of a window unit 72 for extracting the pattern PT, an AD converter 74 for digitally converting the emission luminance value of the extracted pattern PT, and a control unit 76 for determining the emission luminance value. The timing control of the unit 32 and the signal synthesizing unit 34 is also performed at the same time. As the optical sensor 64, a photodiode or the like can be used.

The window section 72 provided in the luminance judging section 70 is provided for extracting a pattern PT as shown in FIGS. 2A and 2B, and is more accurate by measuring only the luminance of the pattern PT. This is for measuring the light emission luminance of the light source 20. Window pulses PH and PV as shown in FIG. 2 are used for extracting the pattern luminance. The window pulses PH and PV are generated by the control unit 76 described later. Specifically, the pattern PT having a predetermined width is determined based on the synchronization signals HD and VD supplied to the control unit 76.
Window pulses PH and PV for extracting are generated. Thereby, only the luminance information of only the pattern PT is extracted.

The window pulses PH and PV newly generated by the control unit 76 can be used as described above, but they can also be generated by the pattern generation unit 32. This is because the window pulses PH and PV can be formed based on the horizontal and vertical drive signals HD and VD supplied to generate the pattern PT.

The luminance information of the extracted pattern PT is AD
The converted luminance information is converted by the converter 74 into digital luminance information, and the converted luminance information is compared with a reference value REF in a control unit 76 composed of a microcomputer. Here, as described above, the emission luminance of the light source 20 is a predetermined value, for example, の of the initial value.
The light emission luminance value at the time when the light emission luminance has decreased to is set as the reference value REF. That is, the light emission luminance value that is a guide to replace the light source 20 is set as the reference value REF.

On the other hand, since the pattern PT is a luminance pattern based on light emitted from the center of the light source 20, measuring the screen luminance of this pattern PT is equivalent to measuring the light emission luminance of the light source 20 itself. . Therefore, the light emission luminance value based on this pattern PT becomes the reference value REF.
When the value falls below the time, it may be determined that the light source 20 is about to be replaced.

When the light emission luminance value falls below the reference value REF, a display signal is generated by the control section 76, and a display element (e.g., light emitting diode LED) 78 for displaying a warning is driven to be turned on. Further, in this example, a warning means 80 such as a buzzer is also driven at the same time to thoroughly notify the operator. Either one may be driven.

Here, an example of the emission luminance determination will be described. The timing of the emission luminance determination may be immediately after the power is turned on as described above, or may be during the period during which an image is displayed.

First, in the former case, as shown in FIG. 3, the power is turned on, and a predetermined period of time (approximately 60 seconds) elapses after the drive current flows through the light source 20 until the emission luminance stabilizes. At the timing, in this example, immediately after the emission luminance is stabilized, the pattern PT is superimposed for a predetermined period of time Wa. However, there is no need to display the video SM. Then, the emission luminance may be measured continuously during the predetermined period Wa, but in this example, the measurement of the period luminance of one frame is performed intermittently a plurality of times (= n).

It is sufficient that n is about 5 to 10. The light emission luminance values measured intermittently are averaged in the luminance judgment section 70, and the averaged light emission luminance values are compared with the reference value REF. The reason why the light emission luminance values are measured and averaged over a plurality of times is to absorb measurement variations.

FIG. 4 shows the latter example. In this example, when displaying a video, the pattern PT is intermittently superimposed. At this time, the section of the pattern PT can be combined with the video SM and projected, or the pattern PT can be displayed instead of the video SM.

The intermittent superimposition timing can be set to an arbitrary time. In this example, the pattern PT is superimposed at 10 minute intervals for one minute, and the luminance measurement and averaging processing are performed n times. The superimposition interval of the pattern PT is not limited to 10 minutes, and may be set to a relatively long interval such as 1 hour, 2 hours, and 1 day.

[0036]

As described above, in the present invention, the deterioration state of the projection light source is determined by measuring the emission luminance of the luminance measurement pattern projected on the screen.

According to this, since the light emission luminance based on the light from the central part of the light source can be measured, the deterioration judgment becomes very accurate. And it has the characteristic that it can be determined without obstructing the optical path or considering the luminance loss as in the related art.

Accordingly, the present invention is extremely suitable for application to a projection type projector used in an on-board machine or various exhibition halls.

[Brief description of the drawings]

FIG. 1 is a system diagram of a main part showing an embodiment of a projection type projector according to the present invention.

FIG. 2 is a diagram showing a screen image.

FIG. 3 is a time chart showing an example of measurement timing of light emission luminance (part 1).

FIG. 4 is a time chart showing an example of measurement timing of light emission luminance (part 2).

FIG. 5 is a conceptual diagram of a conventional projection type projector having a luminance measurement function (part 1).

FIG. 6 is a conceptual diagram of a conventional projection type projector having a luminance measurement function (part 2).

FIG. 7 is a conceptual diagram of a conventional projection type projector having a luminance measurement function (part 3).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Projection projector, 18 ... Screen, 20 ... Projection light source, 32 ... Pattern generation part, 34 ... Signal synthesis part, 40 ... Video projection part, 4
2R, 42G, 42B ... video drive element, 60 ...
・ Brightness measurement unit, 70 ・ ・ ・ Brightness judgment unit

Claims (11)

[Claims] 1. A video signal processing unit, a pattern generation unit that generates a luminance measurement pattern signal driven in synchronization with a synchronization signal supplied to the video signal processing unit, a video signal and a luminance measurement pattern signal A video synthesizing unit, which includes a light source for projection to which the synthesized signal is supplied, a luminance measuring unit that measures the luminance of a luminance measuring pattern projected on a screen, and a luminance measuring unit. And a luminance determining unit to which a luminance signal measured by the unit is supplied, wherein when the measured luminance level is lower than the reference value, the projection type projector is instructed to exchange the projection light source. 2. The projection type projector according to claim 1, wherein said synchronization signal is a horizontal and vertical drive signal. 3. The projection type projector according to claim 1, wherein the luminance measurement pattern is a white rectangular pattern. 4. The projection type projector according to claim 1, wherein said luminance measuring section comprises an optical system and an optical sensor. 5. The projection type projector according to claim 1, wherein said luminance judging section comprises window means for extracting said luminance measuring pattern, and a microcomputer control section. 6. The projection type projector according to claim 1, wherein the luminance measurement pattern is a white rectangular pattern. 7. When the luminance measurement pattern is supplied while a video signal is being supplied, the luminance measurement pattern is intermittently projected onto the screen. The projection type projector according to claim 1. 8. When the luminance measurement pattern is supplied while a video signal is being supplied, the luminance measurement pattern is projected on a part of four corners of the screen. The projection type projector according to claim 7, wherein 9. The projection according to claim 7, wherein when the luminance measurement pattern is intermittently supplied, an average level of luminance levels of the intermittently measured pattern is set as a luminance level for comparison. Type projector. 10. The system according to claim 1, wherein the supply of the video signal is interrupted when the luminance measurement pattern is projected on the screen for a predetermined time after a predetermined time has elapsed since the power was turned on. Item 2. The projection type projector according to Item 1. 11. When the luminance measurement pattern is projected on the screen for a predetermined time after a predetermined time has elapsed since power-on, the luminance measurement pattern is supplied intermittently.
10. The luminance level for comparison, wherein the average level of the luminance levels of the patterns measured intermittently is used as a comparison luminance level.
The projection type projector according to the above.