JPH07281146A - Liquid crystal projector - Google Patents

Abstract

PURPOSE:To provide a liquid crystal projector constituted so that the propriety of the exchanging time of a light source or the distribution of light quantity is displayed on a screen. CONSTITUTION:The liquid crystal projector is provided with a photosensor 31 detecting the light quantity of the light source lamp 2 and an information means driving liquid crystal panels 11R, 11G and 11B and displaying the arrival of the exchanging time of the lamp 2 on the screen when the light quantity detected by the photosensor 31 is lowered to be equal to or under a prescribed value.

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, and more particularly to a liquid crystal projector which displays on a screen the replacement timing of a light source and the suitability of a light quantity distribution.

[0002]

2. Description of the Related Art In a liquid crystal projector, light emitted from a light source is transmitted through a liquid crystal panel on which an image is formed, and the image formed on the liquid crystal panel is projected on a screen to form an image.

In a liquid crystal projector for projecting a color image on a screen, as shown in FIG. 11, a filter 3 is provided from the light emitted from a light source lamp 2 arranged inside the outer case 1.
After removing the ultraviolet rays and infrared rays with, the two separation dichroic mirrors 4 and 5 split the light into red light (R), green light (G), and blue light (B), and two total reflection mirrors 6
7 and two combining dichroic mirrors 8 and 9 combine these spectra into one outgoing optical path and make them incident on the projection lens 10. Three liquid crystal panels 11G, 11R, which form an image of each color on the light path of each color separated
11B is arranged, and these images are superimposed and projected from the projection lens 10 onto the screen.

The liquid crystal panel 11G.1 for each color optical path
Light of each color is incident on the liquid crystal panel 11G on the incident side of 1R and 11B.
A condenser lens 12 for converging to 11R and 11B is provided, and polarizing plates 13 having a light transmitting / shielding function are provided on both sides of the liquid crystal panels 11G, 11R, and 11B on the incident side and the emitting side.

Further, in a single-plate type liquid crystal projector, light from a light source is applied to a single color liquid crystal panel without being split, and an image of this color liquid crystal panel is projected on a screen through a projection lens. .

As the light source lamp 2, a metal halide lamp having a high luminous efficiency, a spectral distribution of natural daylight, and an appropriate color temperature as an image is used. This lamp is replaced when the amount of light decreases with the time of use, and the amount of light decreases to half of the initial value in about 2000 hours. However, this decrease in light intensity varies depending on variations in lamp quality and usage conditions, so in practice, when a certain period of use has passed, when the illuminance of the screen becomes dark, or when the lamp is damaged. Have been replaced.

[0007]

As described above, since the lamps vary depending on quality variations and usage conditions, it cannot always be said that the usage period and the decrease in light amount correspond to each other. There is a case where the light amount is reduced to such an extent that the required performance cannot be obtained before the time elapses, or the required performance is still maintained after a certain period of use.

Further, when the illuminance of the screen is used as a reference, it is judged visually, so that the objectivity is poor, and even if the light quantity is reduced to such an extent that the required performance cannot be obtained, it cannot be replaced, or it is still required. It may be replaced while retaining its performance. That is, up to now, no technique has been found to objectively recognize the necessity of lamp replacement.

On the other hand, when the lamp is replaced, the mounting position of the lamp may change, the optical axis may shift, the position of the image may move, and the brightness distribution of the screen may be biased. Axis adjustment is performed. When performing this optical axis adjustment, it is necessary to visually judge on the screen that the adjustment result is optimum, but this determination is poor in objectivity, and accurate optical axis adjustment is difficult.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal projector in which the replacement timing of the light source and the suitability of the light amount distribution are displayed on the screen.

[0011]

In order to provide a liquid crystal projector in which the replacement time of a light source is displayed on a screen, a first liquid crystal projector of the present invention is provided with an optical sensor for detecting the light amount of the light source, and this optical sensor. Is provided with an informing means for driving the liquid crystal panel to display the arrival of the replacement time of the light source lamp on the screen when the amount of light detected by is decreased to a predetermined value or less.

The second liquid crystal projector of the present invention is
In order to provide a liquid crystal projector in which the light quantity distribution is displayed on a screen, a plurality of optical sensors arranged at a plurality of positions deviated in different directions from the design optical axis, and a liquid crystal based on the output of each optical sensor It is characterized in that a notifying means for driving the panel to display the suitability of the light amount distribution on the screen is provided.

[0013]

In the first liquid crystal projector of the present invention,
When the amount of light detected by the optical sensor falls below a predetermined value, the notification means drives the liquid crystal panel to notify the arrival of the replacement time of the light source lamp over part or the entire screen of the screen. After being formed, the patterns, colors, characters, sentences, etc. are projected on the screen and displayed.

Further, in the second liquid crystal projector of the present invention, the notifying means determines whether the light amount distribution is appropriate based on the objective output of each optical sensor, and drives the liquid crystal panel to display a part of the screen of the screen or A pattern, a color, a character, a sentence, or the like for notifying the determination result is displayed throughout.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, a liquid crystal projector according to an embodiment of the present invention has three components for red light, green light and blue light.
The liquid crystal panels 11R, 11G, and 11B are provided, and the light from the light source lamp 2 is reflected by the reflector 21 and emitted forward, and the filter 3 removes ultraviolet rays and infrared rays, and then two dichroic mirrors 4 for separation. At 5, the light is separated into red light, green light, and blue light.

The separated light of each color is collected on one outgoing optical axis by two total reflection mirrors 6 and 7 and two combining dichroic mirrors 8 and 9 and then enters a projection lens 10 to be illustrated. Not projected on the screen.

Each of the above liquid crystal panels 11R, 11G, 11B
Are arranged on the optical paths of the separated red light, green light, and blue light, and the incident side thereof is a liquid crystal panel 11R corresponding to each color light.
A condenser lens 12 for converging to 11G and 11B is arranged, and a polarizing plate 13 having a light transmitting / shielding function is provided on the incident side and the emitting side thereof.

As the light source lamp 2, a metal halide lamp having a high luminous efficiency, showing a spectral distribution of natural daylight color, and having an appropriate color temperature as an image is used, and is replaced when the amount of light thereof falls below a half of the initial value. Then, the reflector 21 is also replaced together with the light source lamp 2 as needed.

As shown in FIGS. 1 and 2, the outer case 1
Inside, five optical sensors 31 are arranged on the extension line of the green spectroscopic optical path in which the green light separated from the blue light by the separating dichroic mirror 5 enters the combining dichroic mirror 8 via the green liquid crystal panel 11G. It

The synthesizing dichroic mirror 8 has a function of reflecting an effective wavelength range of the green light passing through the liquid crystal panel 11G and transmitting the red light incident from the total reflection mirror 6 through the liquid crystal panel 11R. Since it has a wavelength spectral characteristic as shown in FIG. 3, a part of the incident green light is transmitted and made incident on the optical sensor 31.

The light transmitted through the synthesizing dichroic mirror 8 is applied to a rectangular area shown by a broken line in FIG.
In this area, a hatched rectangular portion shows an effective image area corresponding to the projected image area.

The above five optical sensors 31 are respectively shown in FIG.
The single-crystal silicon photosensor having the wavelength characteristic shown in FIG. 6 and the output characteristic shown in FIG. 6 is formed. As shown in FIG. 4, the center of the effective image area through which the extension line of the design optical axis of the green spectrum passes, and It is arranged at a symmetrical position in the vertical direction about the center and in a symmetrical position in the horizontal direction about the center.

As shown in FIG. 7, each optical sensor 31 is connected to a measuring circuit 40. In this measuring circuit 40, the output of the central optical sensor 31 (31A) is 2 minutes of the initial value measured immediately after the lamp replacement. 1 or less, the display circuit outputs a replacement notification request to the display circuit, and the display circuit drives at least one of the liquid crystal panels 11R, 11G, and 11B based on the replacement notification request to drive the light source lamp 2 to operate. A display indicating that the replacement time has come is formed, and the fact that the replacement time has come is displayed by discoloring, lighting, blinking, pattern display, character display, or the like on a part or the whole of the screen of the screen.

In this embodiment, in order to display the arrival of the replacement time most reliably, when the output of the central optical sensor 31 (31A) becomes one half or less of the initial value measured immediately after the replacement of the lamp, the image is displayed. Is a white raster to clearly indicate the time for replacement.

As described above, the arrival of the replacement time of the light source lamp 2 is objectively detected by the optical sensor 31 (31A) and displayed to the user. It is possible to prevent the use of the light source lamp 2 that does not satisfy the performance or the light source lamp 2 that does not need to be replaced, and it is possible to replace the light source lamp 2 at the optimum time, which reduces the maintenance cost of the liquid crystal projector. it can.

The measuring circuit 40 inputs the outputs of the pair of photosensors 31 (31B) located at symmetrical positions in the vertical direction after the lamp replacement, calculates the deviation, and when the deviation becomes the minimum, the vertical position is calculated. Is output to the display circuit, and the display circuit drives at least one of the liquid crystal panels 11R, 11G, and 11B on the basis of the appropriate display request at the vertical position so that the optical axis of the light source lamp 2 is in the vertical direction. Display on the screen that has been adjusted to the optimum position.

The measuring circuit 40 includes a pair of optical sensors 31 (31) located at symmetrical positions in the horizontal direction after lamp replacement.
The output of C) is input, the deviation is calculated, and when the deviation becomes the minimum, a request for proper display of the horizontal position is output to the display circuit, and the display circuit is the liquid crystal panel 11R, 11G, 11B.
At least one of them is displayed on the screen that the optical axis of the light source lamp 2 has been adjusted to the optimum position in the horizontal direction.

Therefore, the optical sensor 31 (31B / 31C)
By this, the adjustment operator can confirm objectively that the optical axis of the light source lamp 2 is located at the optimum position, which facilitates the optical axis adjustment work and causes the deviation of the optical axis. It is possible to prevent the deviation of the luminance distribution.

A liquid crystal projector according to another embodiment of the present invention shown in FIG. 8 is an application of the present invention to a single plate type liquid crystal projector. In this case, the light is emitted from a light source lamp 2 and directed forward by a reflector 21. The filter 3 removes ultraviolet rays and infrared rays from the received light, and then the condenser lens 12 converges the light on the color liquid crystal panel 11, and the light transmitted through the color liquid crystal panel 11 is incident on the projection lens 10.

A polarizing plate 13 having a light transmitting / shielding function is provided on the incident side and the emitting side of the color liquid crystal panel 11, and the color liquid crystal panel 11 is fixed to the outer case 1 on the incident side of the color liquid crystal panel 11. A mounting frame 22 is provided.

As shown in FIGS. 9 and 10, the mounting frame 22 is formed with an opening 21 which is slightly larger than the effective screen area A1 of the liquid crystal panel 11 (area shown by a broken line rectangle in FIG. 9). Five optical sensors 31A, 31B, and 31 are provided in the area A2 around the area 21 where the light emitted from the projection lens 10 strikes (area hatched in FIG. 9).
C is placed. These optical sensors 31A, 31B, 3
Two optical sensors 31B of 1C are arranged at symmetrical positions in the vertical direction from the center of the effective screen area, and two optical sensors 31C of the remaining three are arranged at symmetrical positions in the horizontal direction from the center of the effective screen area. To be done.

In this case, the optical sensors 31A, 31B, 31
Since C receives the light emitted from the light source lamp 2 before passing through the color liquid crystal panel 11, it is possible to continuously measure the light amount and the light amount distribution of the light source lamp 2 without emitting a white raster image.

Since the other construction, operation and effect of this embodiment are the same as those of the above-mentioned one embodiment, their description will be omitted to avoid duplication.

This embodiment can also be applied to a liquid crystal projector using three liquid crystal panels.

In each of the above embodiments, the light sensor 31 (31A) for measuring the light amount of the light source lamp 2 is provided separately from the light sensor 31 (31B, 31C) for measuring the light amount distribution, but the light amount distribution is measured. Optical sensor 31 (31B ・ 31
It is possible to use one or all of C) as the optical sensor 31 (31A) for measuring the amount of light.

[0037]

As described above, the first liquid crystal projector of the present invention includes the optical sensor for detecting the light amount of the light source and the liquid crystal panel when the light amount detected by the optical sensor falls below a predetermined value. Since the notification means for driving and displaying on the screen is provided, it is possible to accurately detect and display the replacement time of the light source lamp regardless of the quality variation of the light source lamp and the usage state, and the performance is degraded. It is possible to prevent the use of the light source lamp or the replacement of the light source lamp that does not need to be replaced, and it is possible to replace the light source lamp at the optimum replacement time, and it is possible to reduce the maintenance cost of the liquid crystal projector.

The second liquid crystal projector of the present invention comprises:
A plurality of optical sensors arranged at a plurality of positions deviated in different directions from the design optical axis, and means for driving the liquid crystal panel based on the output of each optical sensor to display the appropriateness of the light amount distribution on the screen were provided. Therefore, it is possible to objectively detect whether the position of the optical axis of the light source lamp is appropriate from the deviation of the detected light amount of each optical sensor and display it on the screen, which simplifies the optical axis alignment and shows the result of the optical axis adjustment. It is possible to objectively recognize whether or not it is appropriate, and it is possible to obtain a good image without deviation of the optical axis and bias of the luminance distribution due to this.

[Brief description of drawings]

FIG. 1 is a configuration diagram of the present invention.

FIG. 2 is a configuration diagram of a main part of the present invention.

FIG. 3 is a spectral characteristic diagram of an RG composition dichroic mirror of the present invention.

FIG. 4 is a layout view of an optical sensor of the present invention.

FIG. 5 is a relative sensitivity characteristic diagram of the optical sensor of the present invention.

FIG. 6 is an output characteristic diagram of the optical sensor of the present invention.

FIG. 7 is a circuit diagram of an optical sensor of the present invention.

FIG. 8 is another configuration diagram of the present invention.

FIG. 9 is an explanatory diagram of a main part of the present invention.

FIG. 10 is a perspective view of an essential part of the present invention.

FIG. 11 is a configuration diagram of a conventional example.

[Explanation of symbols]

 2 Light source lamps 31 ・ 31A ・ 31B ・ 31C Optical sensor 40 Measuring means

Claims (2)

[Claims] 1. A light sensor for detecting the light quantity of a light source, and an informing means for driving a liquid crystal panel to display the arrival of the replacement time of a light source lamp on a screen when the light quantity detected by the light sensor falls below a predetermined value. A liquid crystal projector characterized by being provided with. 2. A plurality of optical sensors arranged at a plurality of positions deviated in different directions from a design optical axis, and a liquid crystal panel is driven based on the output of each optical sensor to display the appropriateness of the light amount distribution on a screen. A liquid crystal projector having means.