Screen for liquid crystal projector

• US 5,715,083 A
• Filed: 06/05/1995
• Issued: 02/03/1998
• Est. Priority Date: 06/27/1994
• Status: Expired due to Term

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Takayama, Shigehiko
• Primary Examiner(s): MALLEY, DANIEL PATRICK
• Application Number:
  US08/461,522
• Time in Patent Office: 974 Days
• Field of Search: 359/443, 359/452, 359/453, 359/454, 359/456, 359/459, 359/460
• US Class Current: 359/443
• CPC Class Codes: G03B 21/567 for colour projection G03B21/58, G03B21/60 take precedence
• CPC Class Codes: G03B 21/60 characterised by the nature of the surface
• CPC Class Codes: G03H 1/26 Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

A screen for a liquid crystal projector is provided on which an image formed by the output light from a liquid crystal projector can be recognized even in the presence of extraneous light. The screen is used for a color liquid crystal projector for projecting an image formed on a liquid crystal onto the screen by causing the light from a light source to be transmitted through or reflected from the liquid crystal. Lippman-type holograms (BS, GS, RS) having great reflectances with respect to only the wavelength band of output light of the liquid crystal projector are formed on the screen. As the screen reflects substantially only the output light of the liquid crystal projector and absorbs light having other wavelengths, the reflection of extraneous light is suppressed as much as possible. Therefore, the image projected by the liquid crystal projector is recognizable even in the presence of extraneous light.

Claims

1. A screen for a color liquid crystal projector for projecting an image formed on a liquid crystal onto the screen by causing light from a light source to be transmitted through or reflected from the liquid crystal, the screen comprising:

a layer for reflecting or scattering light having a specific wavelength band and for transmitting other light having wavelengths other than the specific wavelength band; and

a light absorption layer for absorbing light not reflected or scattered by said layer.

3. A screen for a liquid crystal projector as claimed in claim 1, wherein the specific wavelength band of light reflected or scattered by the screen is made narrower than the wavelength band of the output light from color liquid crystal projector by matching the output light with the reflected or scattered light.

4. A screen for a liquid crystal projector as claimed in claim 1, wherein a multilayer-film interference filter having reflection, scattering and diffraction characteristics is provided on the screen and in which the characteristics of the multilayer-fill interference filter are matched with wavelength characteristics of output light from the color liquid crystal projector.

5. A screen for a liquid crystal projector as claimed in claim 1, wherein a hologram recording layer interference filter having reflection, scattering and diffraction properties is provided on the screen, in which the properties of the hologram recording layer are matched with wavelength characteristics of output light from the color liquid crystal projector.

6. A screen for a liquid crystal projector as claimed in claim 5, wherein the hologram recording layer is formed by exposing a photosensitive material to a laser beam.

8. A screen for a liquid crystal projector as claimed in claim 1, wherein output light from the liquid crystal projector is separated into red, green and blue light, and wherein the layer of the screen comprises respective layers for reflecting or scattering light having a specific wavelength band for the respective red, green or blue color and for transmitting other light having a wavelength other than the respective specific wavelength band for the red, green or blue color therethrough, and the light absorption layer of the screen absorbing the light of wavelengths transmitted through the respective layers and not subsequently reflected therefrom.

9. A screen for a color liquid crystal projector as claimed in claim 1, wherein the layer extends over substantially the entire surface of the screen.

10. A screen for a color liquid crystal projector as claimed in claim 1, wherein the layer uniformly reflects or scatters light having the specific wavelength band and transmits other light having wavelengths other than the specific wavelength band, the light absorption layer absorbing light having the wavelengths other than the specific wavelength band not reflected or scattered by said layer.

2. A screen for a color liquid crystal projected for projecting an image formed on a liquid crystal onto the screen by causing light from a light source to be transmitted through or reflected from the liquid crystal, the screen comprising:

a layer for reflecting or scattering light having specific wavelength bands matched with wavelength bands of output light from the color liquid crystal projector and for transmitting other light having wavelengths other than the specific wavelength bands; and

a light absorption layer.

11. A screen for a color liquid crystal projector as claimed in claim 2, wherein the layer extends over substantially the entire surface of the screen.

12. A screen for a color liquid crystal projector as claimed in claim 2, wherein the layer uniformly reflects or scatters light having the specific wavelength band and transmits other light having wavelengths other than the specific wavelength band, the light absorption layer absorbing light having the wavelengths other than the specific wavelength band not reflected or scattered by said layer.

7. An apparatus comprising:

a screen for a liquid crystal projector for projecting an image formed on a liquid crystal onto the screen by causing light from a light source to be transmitted through or reflected from the liquid crystal, the screen including a layer for reflecting or scattering light having a specific wavelength band and for transmitting other light having wavelengths other than the specific wavelength band, and a light absorption layer for absorbing light not reflected or scattered by said layer; and

a liquid crystal projector;

wherein the liquid crystal projector projects output light onto the screen in the presence of extraneous light, the layer of the screen being a layer for transmitting the extraneous light having a wavelength other than the specific wavelength band therethrough, and the light absorption layer absorbing the transmitted light so as to repress reflection of the extraneous light, whereby the image projected by the liquid crystal projector is recognizable even in the presence of the extraneous light.

13. An apparatus as claimed in claim 7, wherein the layer extends over substantially the entire surface of the screen.

14. An apparatus as claimed in claim 7, wherein the layer uniformly reflects or scatters light having the specific wavelength band and transmits other light having wavelengths other than the specific wavelength band, the light absorption layer absorbing light having the wavelengths other than the specific wavelength band not reflected or scattered by said layer.