KR100392632B1 - Projection display apparatus - Google Patents

Abstract

A projection display device for enlarging and projecting an image is disclosed. The projection display apparatus includes an indicator for selecting incident light corresponding to image information and outputting image light, and a plurality of hologram elements capable of transmitting or diffracting the light emitted from the light generating part depending on whether power is applied or not along the light traveling direction. It is arranged, and provided with a color beam generator provided so as to emit color beams of mutually different colors by the drive of a plurality of hologram elements. According to such a projection display apparatus, color beams of different colors can be generated by diffraction method by electrical control, so that the structure is simplified and the restriction on the number of colors of the color that can be generated is alleviated.

Description

Projection display apparatus

The present invention relates to a projection display apparatus, and more particularly, to a projection display apparatus having an improved structure for generating color light.

The projection display device is configured to enlarge and project the image generated by the indicator.

1 is a view showing a conventional projection display device.

Referring to the drawings, the projection display apparatus includes a light source 11, an ellipsoidal reflector 13, a color filter 15, a first focusing lens 17, a relay lens 19, a second focusing lens 21, and an indicator. 23, the projection lens 25 is provided.

The color filter 15 includes a disk having red (R), green (G), and blue (B) filters arranged in different regions, and a motor for rotating the disk.

In the projection display device having such a structure, when the disk of the color filter 15 is rotated at a constant speed, red, green, and blue color beams having a time difference pass through the relay lens 19 and the second focusing lens 21. The indicator 23 is sequentially focused. The display unit 23 selects incident light corresponding to the image information to generate and output image light. That is, when the red light is incident, the indicator 23 selects the incident light corresponding to the red image display information and emits the red image. The green image and the blue image are also generated by the same method as the red image generation method.

However, since the projection display apparatus generates color light by the color filter 15 which is mechanically rotated, image distortion may occur when the rotational speed is changed, and the disk having a light incident effective area must be employed. The size is increased, the noise is generated by the rotational drive, there is a limit to the increase in the rotational speed of the disk has a disadvantage that the restriction on the number of color light that can be generated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a projection display apparatus that can simplify the structure capable of generating color light and can alleviate the constraint on increasing the number of generation of different color light. Its purpose is to.

1 is a view showing a conventional projection display device,

2 is a view showing a projection display device according to an embodiment of the present invention,

3 is a diagram illustrating an example of the color beam generator of FIG. 2;

4A and 4B are views for explaining a process of converting a path of incident light according to a voltage non-applied and applied to the hologram element of the color beam generator of FIG.

FIG. 5 is a cross-sectional view schematically illustrating a unit mirror for explaining an image light generating process of a micro mirror array device applied as an example of the display device of FIG. 2.

<Description of the reference numerals for the main parts of the drawings>

31: light source 33: elliptical reflector

37: focusing lens unit 43: indicator

45: projection lens unit 50: color beam generating unit

According to an aspect of the present invention, there is provided a projection display apparatus including: a display configured to output an image light by selecting incident light corresponding to the image information; A plurality of hologram elements for transmitting or diffracting the light emitted from the light generating unit according to the application of power is arranged along the light traveling direction, and color beams of different colors are driven by driving the plurality of hologram elements. And a color beam generator installed to exit the indicator. The light generating unit is an elliptical reflector for condensing the light emitted from the light source; A focusing lens unit for converting the light beams incident from the ellipsoidal reflector so as to have a cross section of a rectangular shape and emitting the light beams; And a relay lens unit configured to focus the light beam emitted through the focusing lens unit to the color beam generator.

Preferably, the focusing lens unit includes a plurality of fly-eye lenses arranged along a direction perpendicular to the incident direction of the light beam.

In addition, the color beam generator is provided with three hologram elements sequentially diffracted red, green, and blue with respect to the incident light along the light incident direction.

In addition, it is preferable that the indicator is a micro mirror array device in which a plurality of mirrors in which the angle is tilted in accordance with an electrical signal is applied to the light beam generator is applied.

Hereinafter, a projection display device according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing a projection display apparatus according to a preferred embodiment of the present invention.

Referring to the drawings, the projection display apparatus includes a light generating unit, a color beam generating unit 50, an indicator 43, and a projection lens unit 45.

The light generating unit includes a light source 31, an elliptical reflector 33, a focusing lens unit 37, and a relay lens unit 39, 41.

As the light source 31, various known ones capable of emitting white light are applied, and the light source 31 is preferably installed at the focal position of the ellipsoidal reflector 33.

The ellipsoidal reflector 33 reflects the light emitted from the light source 31 to focus on the focusing lens unit 37.

Alternatively, a parabolic mirror (not shown) provided with a light source at a focus position and a collimating lens installed to focus parallel light emitted from the parabolic mirror to the focusing lens unit 37 may be applied instead of the elliptical reflector 33. have.

The focusing lens unit 37 converts the incident light so that its cross section corresponds to a normal screen composition, that is, a rectangular shape having a predetermined aspect ratio. The focusing lens unit 37 may be applied with various known methods such as a fly-eye lens array, a semi-cylindrical lens, a cylindrical lens, or a combination thereof to adjust the optical path so that the light density on the cross section of the rectangular light beam is uniform. .

When the converging lens unit 37 generates the light beam in accordance with the desired screen composition, the utilization efficiency of the light emitted from the light source 31 as the image light is improved.

The relay lens unit 39 and 41 are configured to focus the light beam emitted through the focusing lens unit 37 to the color beam generating unit 50. Preferably, the relay lens portion 39, 41 is composed of at least one lens to provide positive power for incident light. As shown in the illustrated example, when the relay lens unit 39 is formed of a plurality of convex lenses, the lens is arranged such that the light exit surface of the focusing lens unit 37 becomes an object plane and the light incident surface of the indicator 43 becomes an image plane. It is preferable to arrange.

The color beam generation unit 50 is formed by stacking each other to correspond to the number of different color beams to be produced by the hologram element capable of transmitting or diffracting incident light depending on whether power is applied. An example of a color beam generation unit capable of generating red, green, and blue color beams for incident light is illustrated in FIG. 3.

Referring to the drawings, the color beam generator 50 includes three hologram elements 50a, 50b and 50c and a voltage driver 52 for driving the hologram elements 50a, 50b and 50c.

Each hologram element 50a, 50b, 50c includes a liquid crystal layer 51c provided between the substrates and electrode layers 51a, 51b formed on the substrates 51d, 51e so as to face the liquid crystal layer 51c. Equipped. The substrate and the electrode layers 51a and 51b are formed of a transparent material.

In addition, the liquid crystal layer 51c includes a liquid crystal and a polymer film processed to diffract light of a specific wavelength band. Polymeric materials are applied with known materials which can diffract the incident beam at a desired angle. For example, a photopolymeric film known as a polymer material can be applied. The photopolymeric film comprises a polymerizable monomer comprising dipentaerythritol hydroxypentacrylate. The liquid crystal can penetrate into the pores of the polymeric film. The polymeric film is recorded by irradiating light onto the hologram element at each of the object surface and the target position in the desired diffraction direction before or after the association with the liquid crystal. In addition to the liquid crystal layer 51c including the photopolymeric film, a layer interposed between the electrodes 51a and 51b may be applied with various materials capable of transmitting or diffracting incident light at a desired angle depending on whether power is applied. .

The hologram elements 50a, 50b and 50c are processed so as to differ only in the wavelength of selection of the diffraction target, and the driving principle is the same. In addition, the hologram elements 50a, 50b, 50c may be arranged to be spaced apart or in close contact with each other.

In the illustrated example, the color beam generating unit 50 is a reflective type, and a liquid crystal layer 51b formed of a reflective pattern is applied so that the diffracted beam can be reflected. The liquid crystal layer 51b which consists of these is used.

4A and 4B illustrate a path conversion process of light according to a voltage unapplied / applied state for one hologram element 50a for a liquid crystal layer formed of a transmissive pattern. Referring to this, the hologram element 50a diffracts and transmits the incident light at a predetermined angle in the state where no voltage is applied to the electrodes 51a and 51b, and transmits the light regardless of the wavelength when the voltage is applied.

The position of the color beam generator 50 may be determined in consideration of the arrangement position with the display 43 so that the light diffracted by the hologram element may be incident on the image display surface of the display 43.

The color beam generator 50 allows the voltage driver 52 to apply a voltage according to a voltage application pattern corresponding to each hologram element 50a, 50b, 50c according to a red, green, or blue light beam generation cycle. Then, red, green, and blue color beams are sequentially generated and incident on the indicator 43.

The hologram elements 50a, 50b and 50c are preferably configured with an optical system so as to provide maximum diffracted light to the indicator 43 with respect to incident light.

Meanwhile, in order to further generate intermediate color beams other than red, green, and blue, for example, orange and purple, a hologram element capable of selectively diffracting wavelength light of the corresponding color may be further stacked. In this case, since the time constraints for generating additional color beams are not greatly limited by the high speed of light, the limitations for generating different color beams are not large.

The display unit 43 is a device capable of generating image light corresponding to a color image to be displayed with respect to color light which is sequentially incident. For example, the display 43 may be a liquid crystal display device or a micro mirror array device in which a plurality of mirrors are arrayed.

The display 43 is driven in correspondence with the color beams sequentially output from the color beam generator 50 to correspond to the image signals for each color.

The micromirror array device, which is less known to the general public than the liquid crystal display device, includes a plurality of mirrors which are installed to be driven by electrostatic force and convert a reflection angle of incident light. In such a micromirror array apparatus, mirrors arranged two-dimensionally by the number of pixels are driven according to an image signal corresponding to each pixel by micro-micromachining technology so as to display an image by changing an angle of reflection of incident light.

The structure and driving scheme of the micromirror array apparatus are variously known, and the operation principle thereof will be described with reference to FIG. 5, which schematically illustrates one mirror.

Referring to the drawings, the micro-mirror array apparatus includes a mirror 43a provided to be spaced apart from the substrate 43f by a post 43e, a first electrode 43b connected to the mirror 43a, and a mirror ( A second electrode 43c provided on the substrate 43f opposite to 43a is provided. The mirror driver 43d applies a predetermined voltage to the first electrode and the second electrode to correspond to the input pixel signal to adjust the reflection angle of the incident light in a desired direction. For example, when the display light is optically arranged such that the display light is incident on the projection lens unit 45 when the electrostatic attraction is generated in the direction in which the mirror 43a is close to the second electrode 43c, when the power is not applied and the electrostatic repulsion force is applied. At the time of application, the light reflected from the mirror is emitted in a direction out of the projection lens unit 45 and driven to become ineffective light. In this case, the image information can be displayed in the non-power supply type and the electrostatic force application method.

The projection lens unit 45 may include at least one lens to enlarge and project the incident image light. For example, the projection lens unit 45 may be formed of an appropriate lens according to a display method applied to a focus lens, an enlarged lens, or the like.

As described so far, according to the projection display device according to the present invention, it is possible to generate color beams of different colors by diffraction method by electrical control, simplifying the structure, and The advantage is that the constraints are relaxed.

Claims (7)

In a projection display device for enlarging and projecting an image, An indicator for selecting incident light corresponding to the image information and outputting image light; Three hologram elements capable of transmitting or diffracting red, green, and blue light emitted from the light generator according to whether power is applied are sequentially stacked along the light incidence direction, and are driven by driving the hologram elements. And a color beam generator installed to emit color beams of different colors to the display. The projection display apparatus of claim 1, further comprising a projection lens unit configured to enlarge and project the image light emitted from the indicator onto a screen. The method of claim 2, wherein the light generating unit An elliptical reflector for focusing light emitted from the light source; A focusing lens unit for converting the light beams incident from the ellipsoidal reflector so as to have a cross-sectional shape so as to have a rectangular shape; And a relay lens unit for focusing the light beam emitted through the focusing lens unit to the color beam generator. The projection display apparatus of claim 3, wherein the focusing lens unit comprises a plurality of fly-eye lenses arranged along a direction perpendicular to the incident direction of the light beam. The projection display apparatus of claim 3, wherein the relay lens unit comprises a plurality of convex lenses disposed on an optical path. delete The projection display apparatus according to claim 1, wherein the indicator is a micro mirror array device in which a plurality of mirrors are tilted at an angle in response to an electrical signal of light incident from the color beam generator.