JPH04432A - Projection type display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a projection type display device.

[Prior Art] A conventional optical system has a single dichroic mirror that has uniform spectral characteristics based on a certain optical wavelength.

[Problems to be Solved by the Invention] However, in the conventional dichroic mirror, the light flux emitted from the light source in the optical system is not parallel light, so the wavelength of the light reflected and transmitted by this dichroic mirror is
The angle dependence of the dichroic mirror due to the incident angle of light is caused by a shift of several nanometers to more than ten nanometers at both ends of the dichroic mirror. Therefore, the distribution of the red, green, and blue lights separated by the dichroic mirror is not uniform, causing color unevenness on the left and right sides of the projected display screen. The present invention is intended to solve these problems, and its purpose is to provide a dichroic mirror in which reflected and transmitted light does not have angular dependence with respect to an incident light flux that is not parallel light. .

[Means for Solving the Problems] A projection type display device of the present invention has six transmissive panels, each of which is illuminated with light of three source colors of red, green, and blue,
A display device that combines and projects images from three transmissive panels is characterized by having a gicchroic mirror composed of two or more dichroic mirrors having different spectral characteristics.

[Embodiment] FIG. 1 is an optical system layout diagram in an embodiment of the present invention, in which the light beam emitted from the light source 1 is transmitted through blue-reflecting dichroic mirrors 60, 5b1 and green-reflecting dichroic mirrors 4α, 4b.
The light is separated into the three primary colors of red, green, and blue, focused by a condenser lens 6.7.8, transmitted through transmission panels 9, io, and ii for red, green, and blue, and then reflected into a cube prism 12. The images are combined and projected onto a screen or the like by the projection lens 15.

FIG. 2 is a schematic diagram of the incident angle of a non-parallel light beam onto a dichroic mirror.

FIG. 6 is a spectral characteristic diagram showing the angle dependence of a conventional blue reflective dichroic mirror when the incident angle changes by ±5°.

FIG. 4 shows a blue reflective dichroic mirror 3α of the present invention,
3b is a configuration diagram of a green reflective dichroic mirror 4a4b. In this embodiment, a blue reflective dichroic mirror 5a,
The reference wavelengths of the green reflecting dichroic mirrors 4a and 4b are 58 nm and 58 nm, respectively.
0 nm, 595rLrrL.

In this way, in the blue reflective dichroic mirror, 6α and 6
A difference of 10 rL and 77 L is provided between 5a and 6, and the wavelength reflected by 575 is shifted to the shorter wavelength side by 10 nrrL to make the reflection area of blue light uniform.

Similarly, in the green reflecting dichroic mirror, there is a difference of 15rLmO between 4α and 46, and the wavelength reflected by 4b is shifted to the short wavelength side of 15rLrrL to make the reflection area of green light uniform.

FIG. 5 is a layout diagram of another embodiment, in which the keep prism 12 is not used.

[Effects of the Invention] As described above, according to the present invention, by arranging one dichroic mirror composed of two or more dichroic mirrors having different spectral characteristics, the angular dependence of the dichroic mirror can be reduced. This has the effect of easily eliminating color irregularities and obtaining uniform images without color unevenness.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of the optical system of the present invention. 1・・・・・・・・・−・Light source 2・・・・・・・Heat ray reflection filter 5α・・・・
...Blue reflective dichroic 3b...
・Blue reflective dichroic 4α・・・・・・Green reflective dichroic 4b・・・・・・Green reflective dichroic 5・・・・・・Aluminum vapor deposited reflective mirror 6・
・・・・・・・・・Red condensing lens Mirror − α Mira − b Mirror − α Mira − b 7・・・・・・・・・Green condensing lens 8・・・・・・・・・・Blue condensing lens 9... Red transmission type panel 10...
...Transmissive panel 11 for green color...
Blue transmission panel 12...Cube prism 15...Projection lens Figure 2 is a schematic diagram of the angle of incidence on the dichroic mirror. FIG. 6 is a spectral characteristic diagram showing the angle dependence of a conventional blue reflective dichroic mirror. FIG. 4 is a configuration diagram of the dichroic mirror of the present invention. FIG. 5 is an optical system layout diagram of another embodiment. Applicant Seiko Epson Co., Ltd. Agent Patent Attorney Kizobe Suzuki (and 1 other person) Figure 2

Claims (1)

[Claims] In a display device that has three transmissive panels, each of which is illuminated with light from the three source colors of red, green, and blue, and which combines and projects images from the three transmissive panels, two panels with different spectral characteristics are used. 1. A projection type display device comprising a dichroic mirror made up of one or more dichroic mirrors.