KR20080017577A - Lighting optical system - Google Patents

Abstract

An illumination optical system is provided to deflect light while a form of an off-axis illumination optical system is maintained by using a wedge prism. An illumination optical system includes a light source(30) irradiating a white light. An irradiated light is projected into an integrator. A color wheel(34) selectively transmits a predetermined wave of light applied through the integrator. First, second, and third illumination lenses(35a,35b,35c) condenses the transmitted light. A panel(37) allows the light transmitting the illumination lens to be inputted. A prism is positioned between the third illumination lens and the panel to adjust a light path. A wedge prism(36) transmits light condensed on the first, second illumination lens to the third illumination lens by refracting the light. The wedge prism is positioned between the second illumination lens and the third illumination lens.

Description

Lighting optical system {LIGHTING OPTICAL SYSTEM}

1 is a schematic configuration diagram showing a general illumination optical system.

2 is a view schematically showing the deflection of light in the reflection mirror.

3 is a structural diagram of a wedge prism according to an embodiment of the present invention.

4 is a schematic configuration diagram of an illumination light system according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

30: light source 31: reflector

32: lamp 34: color wheel

35a, 35b, 35c: illumination lens 36: wedge prism

37: Panel 38: Prism

The present invention relates to an illumination optical system of an imaging device, and more particularly to an illumination optical system using an off-Axis optical system.

Recently, as the size of TV increases, a projection system has been studied.

Micro Display Devices applied to existing Front Projection and Rear Projection are largely transmissive Liquid Crystal Display (LCD) panels, reflective LCD panels such as LCoS, and Digital Micro- There is a mirror device panel, and the optical system of the projection system is divided into single plate type, two plate type and three plate type according to how many display elements are used.

In general, a transmissive LCD can design an on-Axis illumination system, and a reflective LCD can design an off-Axis illumination system, but most of the illumination systems use an on-Axis illumination system.

However, a display device such as a DMD is an optical switch display device that structurally changes the angle of inclination of the mirror to +10 to -10 degrees to change the reflection angle of the light into two modes. Since the signal is distinguished, an off-axis illumination system that uses an appropriate angle of incidence should be used.

In the case of an illumination system using such a DMD device, the illumination system using a mirror lens and the illumination method using a TIR prism are largely classified.

Referring to Figure 1, a general illumination optical system will be described.

FIG. 1 is a single-plate illumination optical system, in which one lamp 2 uses an ellipsoidal mirror 1 to condense the light of the lamp 2 and the collected light is an integrator 3 and a color wheel 14. The light is collected by the first illumination lens 15a and the second illumination lens 15b and is illuminated by the reflection mirror 16 which deflects the path of light. The reflection mirror 16 reflects the light to the third illumination lens 15c by deflecting the light at a predetermined angle for the design of the off-Axis illumination system. The light illuminated by the third illumination lens 15c is incident on the prism 18 to be applied to the panel 17, and is primarily reflected on the surface of the prism 21 and is incident on the panel 19. Light emitted from the panel 19 passes through the prism 21 and is transmitted to the projection lens (not shown).

When the light emitted from the light source 10 arrives, the panel 17 outputs image information to be projected by a suitable switching or reflection process, and the image information is formed on the screen through the projection lens. Incident. The projection lens is reflected or refracted in any one of the up / down directions in which the projection lens is positioned to be incident.

FIG. 2 is a diagram schematically illustrating deflection of light using the reflection mirror 16 of FIG. 1, in which light is deflected at a predetermined angle to make an off-Axis illumination system.

As shown in FIG. 2A, the reflection area (area) of the reflection mirror 16 is proportional to the amount of incident light, that is, the width d of the incident light. Therefore, as shown in FIG. 2B, in order to deflect the light by a predetermined angle θ to make an off-Axis illumination system, the area of the reflecting mirror 16 becomes L '<L ″, which becomes larger. As it grew, there was a problem that the size of the entire system of illumination optics had to increase.

Accordingly, an object of the present invention is to provide a compact illumination optical system in the illumination optical system using the off-Axis optical system, which was devised to solve the above problems.

The illumination optical system according to the present invention for achieving the above object is a light source for irradiating white light, an integrator to which the irradiated light is incident, a color wheel to selectively transmit only a predetermined wavelength of light passing through the integrator, the transmitted light First, second and third illumination lenses for condensing light, a panel through which light passing through the illumination lenses is input, a prism positioned between the third illumination lens and the panel to adjust an optical path, and the first and second illumination lenses It characterized in that it comprises a wedge prism (Wedge Prism) for refracting the light collected in the light transfer to the third illumination lens.

Here, the wedge prism is located between the second illumination lens and the third illumination lens, the incident surface is a vertical plane, the exit surface is an inclined surface to refracted light or the incident surface is an inclined surface, the exit surface The light emitted is refracted.

At this time, the angle of the inclined surface is 42 ° or less, the refractive index of the wedge prism is 1.51 to 1.52, the refractive critical angle is 21 ° to 27 °.

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

Referring to the accompanying drawings, preferred embodiments of the illumination system according to the present invention will be described.

First, the illumination optical system using the wedge prism according to the present invention denotes the same reference numeral for the same configuration as the above-described prior art.

The present invention is characterized by the use of a wedge prism to refract light generated from the light source 10.

3 is a structural diagram of a wedge prism according to an embodiment of the present invention.

As shown in FIG. 3, the light emitted from the rectangular parallelepiped structure in which one surface is vertical, the light incident surface is the vertical plane 11, and the light is refracted and the exit surface is the inclined surface 12. Refraction In addition, contrary to the above-described structure, the incident surface may be inclined and the exiting surface may be vertical.

At this time, the inclined surface becomes an incident surface or an exit surface to refract incident or emitted light. The angle of the inclined surface is adjusted to 42 ° or less, the refractive index is 1.51 to 1.52, and the refractive critical angle is 21 ° to 27 °. Therefore, the light passing through this inclined surface is refracted in the above-described refractive index and critical angle range.

Typical materials of the wedge prism are glass, polymethyl methacrylate, polystyrene, polycarbonate, polyvinyl chloride, methyl methacrylate / styrene copolymer most transparent materials such as / styrene copolymer (NAS), and styrene / acrylo nitrile.

4 is a schematic structural diagram of an illumination optical system according to an embodiment of the present invention.

As shown in FIG. 4, a light source 30 for irradiating white light, an integrator 33 to which the irradiated light is incident, and a color wheel 34 for selectively transmitting only a predetermined wavelength of light passing through the integrator ), First, second and third illumination lenses 35a, 35b and 35c for condensing the transmitted light, and a panel 37 to which light passing through the illumination lenses 35a, 35b and 35c is input. And a prism 38 positioned between the third illumination lens 35c and the panel to adjust an optical path, and a wedge prism refracting the light collected by the first and second illumination lenses and transmitting the light to the third illumination lens. It is configured to include (Wedge Prism).

The light source 30 includes a lamp 32 that emits white light and a reflector 31 that reflects the light emitted from the lamp and condenses the integrator 33.

The light emitted from the light source 30 passes through the integrator 33 and the light emitted from the light source 30 has uniform illuminance. In addition, it may be shaped into a desired shape while passing through the integrator 33.

The integrator 40 may be a rod-shaped rod lens or an optical tunnel made of a box-shaped mirror.

As such, the output light having uniform illuminance in the integrator 40 or shaped into a desired shape is separated into red (R) / green (G) / blue (B) light and then separated R / G / B. The color wheel 34 irradiating the light in a set and the light separated from the color wheel 34 are collected through the first and second illumination lenses 35a and 35b and pass through the illumination lenses 35a and 35b. One light is refracted by the wedge prism 36 at a predetermined angle and is incident on the third illumination lens 35c.

The color wheel 34 has a circular shape having an R / G / B color separation region, and rotates to separate white light having high luminance emitted from the light source 30 into R / G / B light. It is composed.

The wedge prism 36 maintains the shape of the off-Axis illumination optics and establishes the path of light. Further, by adding a function of diffusing light to the surface of the wedge prism 36 or adding a diffuser plate, a more uniform illumination light can be obtained.

Light passing through the third illumination lens 35c is incident on the prism 38 to be applied to the panel 37.

At this time, the prism 38 has a boundary surface, and the light transmitted from the third illumination lens 35c is first reflected by the surface of the prism 44 and is incident on the panel 37, but the panel 37 The light emitted from is refracted or reflected by the prism 38 and transmitted to the projection lens (not shown).

When the light emitted from the light source 30 arrives, the panel 37 outputs light having image information by appropriate switching or reflection, and the light having the image information is the prism 38. The image is imaged on the screen (not shown) through the projection lens (not shown) positioned in the direction of reflection or refraction at.

The prism 38 separates / combines the incident light according to the number of panels 37 and transmits the light carrying the image information to the projection lens according to the control of the panel 37. This prism 38 mainly uses a TIR prism or an X prism.

The panel 42 may be any one of a digital micromirror device (DMD), a liquid crystal on silicon (LCoS), and a liquid crystal device (LCD). Such a panel 37 may be referred to as a micro switching element.

The panel 37 may be divided into a single panel panel, a two panel panel, and a three panel panel according to the number of liquid crystal panels, and may be divided into a transmissive panel and a reflective panel according to a method of converting a light beam into image information.

As shown in FIG. 4, the illumination optical system has a structure in which the gaps of the above-described optical components are narrowly arranged. Therefore, in order to change the optical path at a predetermined angle in the illumination optical system to configure the off-Axis optical system, if the reflection mirror is used in a conventional manner, as shown in Figs. The size of the system is bound to grow.

However, according to the configuration of the present invention described above, by configuring the illumination optical system using the wedge prism 36, a compact illumination optical system can be configured.

The above embodiment is an example for explaining the technical idea of the present invention in detail, and the present invention is not limited to the above embodiment, various modifications are possible, and various embodiments of the technical idea are all protected by the present invention. It belongs to the scope.

The illumination optical system according to the present invention as described above can deflect the light while maintaining the shape of the off-Axis illumination optical system using a wedge prism.

Therefore, compared with the illumination optical crab using the reflection mirror, the margin of component space is increased, and there is an effect that a compact illumination optical system can be comprised.

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 (7)

A light source for emitting white light; An integrator in which the irradiated light is incident; A color wheel for selectively transmitting only a predetermined wavelength of light passing through the integrator; First, second and third illumination lenses for condensing the transmitted light; A panel through which light passing through the illumination lenses is input; A prism positioned between the third illumination lens and the panel to adjust an optical path; And And a wedge prism for refracting and condensing the light collected by the first and second illumination lenses to the third illumination lens. The method of claim 1, wherein the wedge prism, Illumination optical system, characterized in that located between the second illumination lens and the third illumination lens. The method of claim 1, wherein the wedge prism, An illumination optical system for refracting outgoing light with the incident surface as a vertical plane and the exit surface as an inclined plane. The method of claim 1, wherein the wedge prism, An illumination optical system characterized by refracting outgoing light with an entrance plane as an inclined plane and an exit plane as a vertical plane. The angle of the inclined surface of claim 3 or 4, An illumination optical system characterized by being 42 ° or less. The refractive index of the wedge prism of claim 3 or 4, Illuminating optical system, characterized in that 1.51 to 1.52. The refractive threshold angle of the wedge prism of claim 3 or 4, An illumination optical system, characterized in that it is 21 ° to 27 °.

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