JP2000180823A - Illuminator for projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain low power consumption, long life and high efficiency, to miniaturize a device and to reduce a cost. SOLUTION: Light emitting elements G, B, R with different colors are arranged on a substrates 11, 12 as a projector illumination light source, and at least two colors light emitting elements G, B are controlled so as to light emit in different time bands on the time base, and liquid crystal drive type space modulation elements 13, 17 forming images answering to respective color beams are arranged on its optical path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for a projector which is effective for, for example, a video display device.

[0002]

2. Description of the Related Art Single-panel DMD (Digital Mic)
2. Description of the Related Art There is a display device that displays an image using a Mirror Device. FIG. 5 shows a conventional display device.

[0005] Reference numeral 51 denotes a light source, and the light reflected by the reflector 52 is incident on a first focus lens 53 and is irradiated on a part of a rotating color filter 54. The rotating color filter 54 is rotated by the motor 35, and R, R with respect to the optical path.
G and B filter units can be arranged. The colorized light is applied to the DMD 57 via the second focus lens 56. The DMD 57 outputs images corresponding to R, G, and B in synchronization with the R, G, and B lights. This DMD57
Is projected on a screen 59 via a projection lens 58.

The light source 51 always has a constant light emission luminance. The rotating color filter 54 is rotated at a rotation speed of one to several times in synchronization with the vertical synchronization of the video signal. DMD5
7 synchronizes with the rotation of the rotating color filter 54,
When each of the G and B lights is projected, an image corresponding to each color is displayed, and the gradation is controlled by controlling the reflection time of each pixel.

[0005]

According to the conventional display device, there are problems such as high cost, complicated structure, large power consumption, and short life.

Therefore, the present invention provides low power consumption, long life,
It is an object of the present invention to provide a lighting device for a projector, which can obtain high efficiency, and can reduce the size and cost of the device.

[0007]

According to the present invention, in order to achieve the above object, light emitting elements of different colors are arranged on a substrate as light sources, and at least two light emitting elements of different colors are different on a time axis. It is characterized in that it is controlled to emit light in a time zone, and a liquid crystal driving type spatial modulation element for forming an image corresponding to each color of light is arranged in the optical path.

According to the above means, the light emitting device is small, consumes low power, is durable, and can be realized at a small size and at low cost.

[0009]

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

FIG. 1A shows an embodiment of the present invention. On a first substrate 11, a green (G) light emitting element (LED) and a blue (B) light emitting element are arranged in a two-dimensional array. The light-emitting elements (R) are arranged on the second substrate. For example, the same number is used for each light emitting element, for example, 500. The light emitted from the light emitting element of the substrate 11 is incident on the polarization beam splitter 14, the light having a certain polarization is incident on the reflective liquid crystal panel 13, and the reflected light having changed the polarization passes through the polarization beam splitter 14. , Into the combining prism 15. The light emitted from the light emitting element of the second substrate 12 is incident on the polarization beam splitter 16 and then the light having a certain polarization is reflected on the reflection type liquid crystal panel 17.
And the light whose polarization has been changed passes through the polarizing beam splitter 16 and enters the combining prism 15. The combining prism 15 emits each incident light in the same direction. The emitted light is projected on a screen (not shown) via the projection lens 18.

FIG. 1B shows a state in which light emitting elements G and B are arranged on the first substrate 11, and FIG.
3 shows a state in which the light emitting elements R are arranged on the second substrate 12.

FIG. 2 is a timing chart for explaining the operation of the above-described lighting device. In this lighting device, the light emission time of the light emitting element for each color is divided. That is, at least the light emission time zones of the light emitting elements for each color provided on the same substrate are different.

FIGS. 2A and 2B show a first example of light emission time control. In one vertical period, in this example, the light emitting element R is in the entire time zone (100% of one vertical period).
The light emitting elements G and B are set to emit light for 40% and 60% of one vertical period.

On the other hand, the reflection type liquid crystal panels 13 and 17 corresponding to the light emitting elements of each substrate are driven so that an image corresponding to the color is formed by the liquid crystal in accordance with the time zone of the color to emit light. Therefore, a video signal corresponding to red is always supplied to the reflective liquid crystal panel 17 (FIG. 2).
(A)). On the other hand, video signals corresponding to green and blue are supplied to the reflective liquid crystal panel 13 in a time-division manner (FIG. 2).
(B)).

In the above example, the ratio of the light emitting time in one vertical period of the light emitting elements R, G and B is set to 100%, 40%, 6%.
The ratio of 0% is a ratio selected for obtaining a white balance according to the number of the above-described elements, and is not necessarily limited to this ratio.

In the above example, the light emission time periods of the light emitting elements G and B are allocated on the substrate 11 side as shown in FIG. 2B, but as shown in FIG. Light emission may be performed separately to suppress coloration, flicker, and the like.

The present invention is not limited to the above embodiment.

FIG. 3 shows still another embodiment of the present invention. In this embodiment, three color light emitting elements R,
This is an embodiment in which G and B are arranged on one substrate 21. The light emitted from the light emitting element is incident on the polarization beam splitter 22, and light having a certain polarization is incident on the reflection type liquid crystal panel 23, and the reflected light having changed polarization passes through the polarization beam splitter 22 and is projected on the projection lens. 24, and is projected on a screen (not shown).

The light emitting elements R, G, and B are driven in a time-division manner, and the reflection type liquid crystal panel 23 is set in accordance with a light emission time zone for each color.
Forms an image corresponding to each color. FIG. 3B shows an example in which the light emitting elements R, G, and B are driven in a time-division manner. Here, the required amount of the light emitting element is R = 500,
G = 500, B = 500, and as lighting time, R:
Assuming that G: B = 5: 2: 3, R, R in FIG.
The respective periods of G and B are set to 5: 2: 3.

In the driving method shown in FIG. 3B, the lighting periods of the respective light emitting colors are continuous, but the light emitting times of the same color may be further dispersed. FIG. 3 (c)
Is an example in which the red lighting time is dispersed, but even in this case, the relationship of R: G: B = 5: 2: 3 is maintained as the lighting time. Further, as shown in FIG. 3D, the lighting time of each emission color may be dispersed more finely. FIG. 3E shows an arrangement of light emitting elements when the substrate 21 is viewed from the front.

FIG. 4 shows an example of an electrical signal processing system in each of the above embodiments.

The R, G, and B analog video signals and vertical synchronizing signal are supplied to an analog processing circuit 31. The video signal is input to an analog-to-digital (A / D) converter 32, digitized, and input to a digital processing circuit 34.
In the digital processing circuit 34, a frame memory 35
And the R, G, and B video signals are read out independently using the frequency converter 36, and given to the digital / analog (D / A) converter 37. Then, the output of the D / A converter 37 is supplied to the reflection type liquid crystal panel 38. Frequency converter 36
Converts the frequency of each of the R, G, and B signals based on the timing chart shown in FIG. 2 or FIG. The frame memory 35 is used to temporarily store the R, G, and B signals, respectively, to obtain input / output timing.

The control circuit 39 supplies a drive timing signal to the digital processing circuit 34 and other circuits in order to obtain the drive shown in FIG. 2 or FIG. Further, the timing chart shown in FIG. 2 or 3 may be arbitrarily selected.

The digital processing circuit 34 supplies a power supply 4
1 and a switch S between each light emitting element 42, 43, 44
A timing signal for controlling S1, S2, and S3 is output, and switches S1, S2, and S3 are controlled.

In the above description, the reflection type liquid crystal panel has been described. However, the present invention is not limited to this, and may be a transmission type liquid crystal panel or a DMD (digital tile mirror device). The transmissive liquid crystal panel has a configuration in which a liquid crystal panel and a substrate having R, G, and B light emitting elements are arranged behind the liquid crystal panel so as to overlap each other. Even with this configuration, a small-sized and low-cost lighting device can be provided. When the DMD is used, for example, in the configuration shown in FIG. 5, if the light source is replaced with a substrate provided with R, G, and B light emitting elements, the number of lamps and rotating systems can be reduced, and the size, weight, and cost can be reduced. Can be realized.

In the embodiment shown in FIG. 1, the light emitting element R
Is provided on one substrate, and the light-emitting elements G and B are provided on one substrate. However, since the luminous efficiency of R is inferior to that of G and B, this configuration is adopted to obtain a balance. As long as the light emitting element has high luminous efficiency, the embodiment shown in FIG. 3 may be used.

[0027]

As described above, according to the present invention,
Low power consumption, long life, and high efficiency can be obtained, and the size and cost of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of the present invention.

FIG. 2 is a timing chart shown for explaining an operation example of the embodiment of FIG. 1;

FIG. 3 is a diagram for explaining another embodiment of the present invention and an operation example thereof.

FIG. 4 is a diagram showing an electric system of the device of the present invention.

FIG. 5 is a diagram showing a conventional projector lighting device.

[Explanation of symbols]

11, 12: substrate, 13, 17: reflective liquid crystal panel, 1
4, 16: polarizing beam splitter, 15: prism, 1
8 Projection lens.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 9/31 H04N 9/31 C 5C060 (72) Inventor Hisayuki Mihara 3-3-9 Shimbashi, Minato-ku, Tokyo No. Toshiba Abu E Co., Ltd. (72) Inventor Tsukasa Sakamoto 1-9-2 Hara-cho, Fukaya-shi, Saitama F-term in Toshiba Fukaya Plant (reference) 2H088 EA14 EA16 HA06 HA20 HA23 HA24 HA28 MA05 MA06 MA16 MA20 2H091 FA10X FA21X FA26X FA45Z FD24 GA11 LA11 LA12 LA16 LA30 MA07 2H093 NC16 NC24 NC29 ND08 ND17 ND34 ND39 ND42 ND47 ND54 NE06 NG02 2H099 AA12 BA09 CA01 DA05 5C058 AA09 BA03 BA03 BA03 BA03 BA03 BA03 BA03 BA03 BA03 BA03 BA03 BA03 BA03 BA03 GB02 HB24 HB26 HC00 HC01 HC09 HD07 JB00

Claims (2)

[Claims] 1. A light-emitting element of a different color is arranged on a substrate as a projector illumination light source, and at least two light-emitting elements of a color are controlled to emit light in different time zones on a time axis. A lighting device for a projector, comprising a liquid crystal driving type spatial modulation element for forming an image corresponding to each color light. 2. A white balance is set by adjusting a lighting time of a light emitting element of a different color among the light emitting elements on a time axis to set a mixing ratio of color light. The lighting device of the projector according to claim 1.