KR20030082737A - Hologram Optical and Liquid Crystal Device Panel including Hologram Optical Element - Google Patents

Abstract

PURPOSE: A hologram optical system and a reflective LCD panel with a hologram optical element using the same are provided to easily manufacture a hologram optical element outputting a beam in a certain direction regardless of directions of an incident beam, thereby improving a viewing angle characteristics and brightness of a reflective LCD panel. CONSTITUTION: A photosensitive film is arranged at an interference area of a beam parallel entering a conical optical system and a beam reflected to the conical optical system for having different refraction rate patterns by the interfered beams and outputting the beam in a certain direction to an incident beam. A hologram optical element(20) is formed of the photosensitive film and outputting a beam to the photosensitive film in a certain direction. A reflective LCD(Liquid Crystal Panel) panel is arranged in front of the hologram optical element and modulates the beam entered by the hologram optical element in the certain direction by entering a background beam to output the modulated beam in a certain direction.

Description

Holographic Optical and Liquid Crystal Device Panel including Hologram Optical Element with Hologram Optical System and Hologram Optical Device Using the Same

The present invention relates to a reflective LCD panel having a hologram optical system and a hologram optical element using the same.

Holographic Optical Element (HOE) is produced by recording interference patterns formed by several (usually two) beams with coherence, so the pattern spacing is not uniform but generally well-defined fringe spacing It has a diffraction grating structure having

Therefore, the holographic optical element is a diffractive optical element that operates according to the diffraction law, not the reflection or refraction law, and the most representative diffraction type element is the hologram diffraction grating.

The hologram lens is a diffractive element, but functionally, it functions as a refractive element or a reflective element like a conventional lens.

In addition, the holographic optical element can be obtained by recording on a photosensitive material such as a photopolymer in the same way as a photographing method, compared to conventional optical elements obtained through surface processing, so that the mass production is easy.

The direction of light diffracted by the holographic optics is determined by the fringe structure of the surface of the holographic optics, while the diffraction efficiency of the diffracted light is determined by internal fringe structures such as fringe direction and refractive index modulation.

In order to reduce the dependence of the azimuth angle in manufacturing such a holographic optical device using a photopolymer, it was possible by injecting lasers in various directions and superimposing them.

However, this is difficult to align the optical system, there is a difficulty in adjusting the amount of light of each laser.

For example, conventional reflective or transmissive HOEs have been used as HOEs for diffracting light at specific angles.

In the HOE, as shown in FIG. 1A, an interference pattern of overlapping light is recorded on a recording medium 1, that is, a recording plate 1 such as a photo plate, due to the coherence of light of a laser. When one of the two lights, that is, the reference light 2 is incident on the recording plate HOE 1, the light is diffracted in the direction of the other light that originally caused the interference, that is, the object light 3, and proceeds. Done.

The HOE 1 of FIG. 1B manufactured by the method of FIG. 1A diffracts the reference light 2 incident by the laser at a predetermined angle, and the object light of FIG. 1A according to the diffraction efficiency as shown in FIG. 1B. (3) adjusts the intensity of the diffracted light (3-1) and transmitted light (3-2).

Normally, this HOE 1 is diffracted at a predetermined angle only with respect to the wavelength used, and is diffracted at different angles as light of different wavelengths are incident.

Therefore, if white light is used, HOE should be produced for each wavelength, which should be made by injecting light of different wavelengths at the same time, or by making incidents with different angles to give the same effect. And the HOE plate used here is mainly used a photopolymer.

In the HOE according to the related art, the angle of incidence incident on the HOE is determined, but in order to produce a reflective HOE irrelevant to the direction using a recording plate (eg, a photopolymer), the angle of incidence is adjusted. It is also necessary.

That is, when the angle of incidence is determined, the angle of reflected light should be kept constant with respect to the azimuth angle, even if the angle of incidence is incident in any direction in the form of a cone.

Therefore, in order to have such a symmetry, it is possible by injecting a laser at multiple azimuth angles and superimposing them, which causes difficulty in aligning the optical system in each case.

Accordingly, an object of the present invention is to provide a holographic optical system that outputs light in a constant direction by using a conical optical system regardless of the direction of incident light.

Another object of the present invention is to make an optical element using the holographic optical system as described above, by placing the optical element on the rear side of the reflective LCD panel to modulate the light in a predetermined direction of the LCD panel in the edge region of the reflective LCD panel The present invention provides a reflective LCD panel which removes the direction dependence of light by allowing the modulated output light to be displayed well.

1A and 1B illustrate a manufacturing principle of a holographic optical device according to the prior art.

Figure 2a shows a manufacturing apparatus and principle of the holographic optical element (HOE) using a holographic optical system according to the present invention.

2B is a perspective view of the conical optical system constituting the hologram optical system.

FIG. 2C is an enlarged view of the original portion of FIG. 2A.

3 illustrates a holographic optical element according to the present invention.

4 shows a reflective LCD panel with holographic optics according to the present invention.

* Explanation of symbols for main parts of the drawings

1: record board or HOE 2: reference light

3: objective light 3-1: diffracted light

3-2: transmitted light 10: conical optical system

20: hologram optical element (HOE) 30: reflective LCD panel

Features of the holographic optical system according to the present invention for achieving the above object is a light source; Conical optical system; Hologram optics disposed in an interference region of light incident in parallel from the light source to the conical optical system and reflected from the optical system and having different refractive index patterns by the interfering light and outputting light in a constant direction with respect to the incident light. It is provided with the element HOE.

A feature of the reflective LCD panel with a holographic optical element according to the present invention for achieving the above object is formed of a photosensitive film having a different refractive index pattern by an interference fringe, and for the light incident at a predetermined angle A hologram optical element for outputting light in a predetermined direction with respect to the photosensitive film; The reflective LCD panel is disposed on the front surface of the holographic optical element and modulates the light incident in a predetermined direction by the holographic optical element to output the light in a predetermined direction of the panel.

The hologram optical element is composed of one film having different refractive index patterns for each of the R, G, and B wavelengths of light incident on the reflective LCD panel, or for each of the R, G, and B wavelengths of light incident on the reflective LCD panel. It consists of three films, each having a different refractive index pattern.

A photopolymer film is used as the photosensitive film.

According to an aspect of the present invention, the interference pattern of the incident light and the reflected light is made into a hologram optical element using a conical optical system, and the background light is incident on the reflective LCD panel which displays using the background light. When transmitting and reflecting the holographic optical element, the reflection is reflected in the normal direction of the reflective LCD panel irrespective of the incident direction of the background light, so that the upper and lower parts of the LCD panel are not significantly affected by the height or direction of the human eye. Or, the pixels displayed on the left and right sides can be seen well.

In the production of HOE having such a function by using a photopolymer, the main point is to make it simpler and more efficient, and to avoid orientation dependency.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Referring to the accompanying drawings, a preferred embodiment of a reflective LCD panel having a holographic optical system and a holographic optical element using the same according to the present invention will be described.

Figure 2a shows a manufacturing apparatus and principle of the holographic optical element (HOE) using a holographic optical system according to the present invention.

2B is a perspective view of the conical optical system constituting the hologram optical system.

As shown in FIG. 2A, the hologram optical system includes a light source (not shown), a conical optical system 10, a beam incident in parallel from the light source to the conical optical system 10, and a beam reflected on the optical system 10. It is composed of a holographic optical element (HOE) 20 disposed in the interference region and having a different refractive index pattern and outputting light in a normal direction to incident light by the interference light.

As shown in Figure 2a, when the conical optical system 10 is incident to a parallel laser beam, the light is reflected at the lower portion at the lower part of the same angle at the azimuth angle to return.

When the reflection optical system is made into a cone conical optical system 10 and a parallel laser beam is incident on the incident surface conical optical system, the light is uniform at the lower mirror surface 10-1 of the conical optical system 10. The angle is reflected back at the same azimuth angle.

At this time, the photopolymer film is placed where light incident on the side and reflected from the mirror (A, B) and light incident on the optical system overlap each other, and the interference of light incident perpendicularly to the reflected light Make HOE.

When the light is incident in all directions of the cone during the production of the HOE, the light incident on the side interferes with each other and the light incident on the side is not diffracted as opposed to the vertical direction of the originally intended optical system. There is a possibility that A interferes with each other and A is diffracted in the direction of B.

Accordingly, in order to prevent this, the HOE 20 may be made while diffractive the conical optical system 10 and the photopolymer film in front of the conical optical system 10.

That is, FIG. 2C is an enlarged view of the original portion of FIG. 2A. The photopolymer film is placed at the position where the reflected light and the incident light overlap, and the interference between the two lights is transmitted to the holographic optical element (HOE) 20 When created, the HOE 20 having the same function as that of FIG. 3 is created.

When the incident light D is incident on the HOE 20, the diffracted light E comes out in a direction perpendicular to the HOE 20. The HOE 20 thus made is reflected in the same direction even when light is incident from any angle without dependency of azimuth angle, so that a person can see the image well without changing the position according to the background light.

Looking at the production principle of the HOE in detail as follows.

First, the intensity of light due to interference such as reinforcement and cancellation of incident and reflected beams of the conical optical system 10 is recorded in the photopolymer film.

Since the light intensity where the constructive interference occurs is strong and the light intensity where the destructive interference occurs is weak, if you record the intensity of the light intensity on the photopolymer film, the film reacts to the light. The refractive index changes.

The change of the refractive index of the photopolymer film (medium) induces a path difference of light passing through the medium, and the high refractive index causes the beam to be broken a lot, and the low refractive index makes the beam be less.

Therefore, when light enters the photopolymer film due to the refractive index pattern recorded on the photopolymer film, the light is output in a predetermined direction without following the principle of refraction.

The photopolymer film is a photosensitive resin, and is a polymer or a polymer composition in which a change in molecular structure occurs due to the action of light, resulting in a change in physical properties.

By changing the optical properties of the photopolymer to produce a holographic optical element (HOE) 20 to output the light output in the desired direction.

In this case, the conical optical system 10 to which the photopolymer film is attached is very efficient in driving the incident background light having a predetermined angle of incidence into the center of the LCD panel.

The reinforcement or destructive interference is caused by the superposition of the angles incident on the photopolymer film attached to the conical optical system 10 and the reflected angles, and accordingly, a change in the magnitude of light is recorded on the photopolymer film, thereby refractive index of the photopolymer film. After changing, the reflection angle of the incident angle incident on the film does not have the same angle as the incident angle and is diffracted to proceed even if the conical optical system 10 is separated from the film.

That is, the light is reflected at a predetermined angle according to the refractive index of the film, so that light is reflected in a desired angle, preferably in a vertical direction of the field of view, so that the LCD panel screen can be easily seen.

Since the conical optical system 10 has the advantage of driving the background light to the center of the panel not only in one plane but also at an incident angle incident at a predetermined angle in space, light incident and reflected by the conical optical system 10 is reflected. When the interfering portion of the light incident on the conical optical system 10 is recorded on the photopolymer film, the viewing angle may be normalized with respect to the background light incident at any angle. In other words, the dependency on the azimuth can be reduced.

4 shows a reflective LCD panel with holographic optics according to the present invention.

As shown in Fig. 4, the HOE (20) is formed of a photosensitive film having a different refractive index pattern by an interference fringe, and outputs light in a predetermined direction, for example, a perpendicular direction to the photosensitive film with respect to light incident at a predetermined angle. And a reflective LCD panel 30 disposed on the front surface of the HOE 20 and modulating the light incident in the vertical direction by the hologram optical element 20 by inputting the background light. It is configured to include).

As shown in FIG. 4, the background light can be efficiently collected in the visible direction.

In the reflective LCD panel 30 displaying the background light, the background light is incident on the LCD panel 30, passes through the upper surface of the LCD panel 30, and passes through the liquid crystal cell to the lower surface. Then, the light F incident on the bottom surface is reflected through the HOE 20 and reflected upward, and is displayed while passing through the bottom surface, the liquid crystal cell, and the top surface of the LCD.

Here, when the background light incident from the side is reflected from the flat top and the top surface, the reflected light exits in a different direction when viewed from the front of the upper surface as glare (G) that is reflected at the same angle as the incident angle. Although it is not a problem in the display, the light that is incident on the lower surface of the LCD panel and reflected from the HOE 20, that is, the lower reflected light, affects the contrast of the display. Rather than exiting, it is better to reflect in the vertical direction at right angles to the surface where the observer's eye in front of the upper surface is located.

Accordingly, the HOE 20 is disposed on the rear surface of the LCD panel 30 so that the background light incident from the side surface is reflected from the lower portion of the reflective LCD panel 30 and has a large amount of light in the front direction.

The HOE20 having such a function is manufactured by using a photopolymer so that light is reflected in the same direction at any angle without depending on the azimuth angle, so that a person does not have to change the position according to the background light of the reflective LCD panel 30. You will be able to see the statue well.

In addition, using the holographic optical device 20 improves the viewing angle characteristics of the reflective LCD panel 30 with high efficiency and simplicity.

In addition, when the light incident to the center is diverted by the concave lens, the viewing angle can be increased.

The HOE 20 is composed of one photopolymer film having different refractive index patterns for each of R, G, and B wavelengths of light incident on the reflective LCD panel 30, or the reflective LCD panel 30 It consists of three photopolymer films which have a refractive index pattern different for each of R, G, and B wavelengths of the light incident on.

That is, since the refractive indices of the same medium are different according to the wavelengths of the R, G, and B light, the interference is reflected in the same direction with respect to the background light incident on the reflective LCD panel 30 for each of the R, G, and B wavelengths. The patterned photopolymer film should be provided.

Alternatively, the same pattern of interference fringes may be formed on one film.

And this has the advantage that does not need to change the experimental device according to the laser wavelength used, respectively for the laser having a color of red (R), green (G), blue (B) when manufacturing the HOE for LCD for full natural color You can also solve the problem of color shifting depending on the angle by making a film.

In addition, the width of the angle with respect to the incident angle may be adjusted by adjusting the properties of the photopolymer during manufacturing.

As described above, the reflective LCD panel including the holographic optical system and the holographic optical element using the same has the following effects.

Using a conical optical system, it is possible to easily manufacture a hologram optical element that outputs light in a constant direction, for example, a vertical direction, regardless of the direction of incident light.

By producing hologram optical element having this function, it collects background light efficiently in the visible direction, so that light is reflected in the same direction regardless of azimuth angle regardless of azimuth angle, so that a person does not have to change the position according to background light. When applied to a reflective LCD, it is possible to see well and to see a bright image regardless of the direction of the background light, improving the viewing angle characteristics and brightness of the reflective LCD panel, and providing a simple and efficient LCD panel. do.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (6)

Light source; Conical optical system; A photosensitive film disposed in an interference region of light incident in parallel from the light source to the conical optical system and reflected from the optical system, and having a different refractive index pattern by the interfering light and outputting light in a constant direction with respect to the incident light; Hologram optical system characterized in that it comprises. The hologram optical system of claim 1, wherein the photosensitive film is a photopolymer film. A hologram optical element formed of a photosensitive film having different refractive index patterns by an interference fringe, and outputting light in a predetermined direction with respect to the photosensitive film with respect to light incident at a predetermined angle; Holographic optics, characterized in that it comprises a reflective LCD panel disposed on the front surface of the holographic optical element, the background light is incident to the holographic optical element to modulate the light incident in the predetermined direction and output in a predetermined direction. Reflective LCD panel with elements. The reflective LCD panel with a holographic optical element according to claim 3, wherein the photosensitive film is a photopolymer film. The hologram optical device of claim 3, wherein the holographic optical device simultaneously has different refractive index patterns for each of R (Red), G (Green), and B (Blue) wavelengths of light incident on the reflective LCD panel. Reflective LCD panel having a. 4. The holographic optical device of claim 3, wherein the holographic optical device comprises three films having different refractive index patterns for each of R, G, and B wavelengths of light incident on the reflective LCD panel. Type LCD panel