KR20070009177A - Optical engine for adjusting location of prism - Google Patents

Abstract

An optical engine of adjusting the position of a prism is provided to easily adjust the size of a screen by adjusting the position of the prism in the optical engine. An optical engine includes a light source, a reflection type display panel, a prism(30), at least one lens(40), a projection lens, a total reflection mirror, and a guide mechanism. The prism transmits light irradiated from the light source and reflects the light reflected from the reflection type display panel and irradiated again by a predetermined angle. The forward and rearward position of the prism can be adjusted in a direction parallel to the optical axis passing through at least one lens by the prism guide mechanism so that the size of the screen can be adjusted.

Description

OPTICAL ENGINE FOR ADJUSTING LOCATION OF PRISM}

Figure 1 shows the appearance of the optical engine in the assembled state.

2 is a view showing a part of a projection system using a reflective display panel according to the prior art.

3 is a view showing a BFL adjustable area inside an optical engine viewed from the side according to a preferred embodiment of the present invention.

4 is a schematic illustration of a prism guide mechanism of an optical engine, in accordance with a preferred embodiment of the present invention.

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

30: prism 40: lens

50: projection lens 60: total reflection mirror

71: screw type rod

The present invention relates to a projector optical engine, and more particularly to a projector optical engine configured to be able to adjust the position of the prism inside the optical engine to easily adjust the screen size on the screen.

In general, a spatial light modulator, which is an apparatus for projecting optical energy onto a screen, may be used in various fields such as optical communication, image processing, and information display apparatus. Typically, such devices are classified into a direct image display device and a projection image display device according to a method of displaying optical energy on a screen.

The dual projection image display device may be classified into a front projection method and a rear projection method according to a direction in which an image is projected on a screen. Among them, the rear projection apparatus is in the spotlight due to the feature of displaying a relatively bright image even in a bright environment.

The typical projection imaging apparatus of the rear projection apparatus mainly uses a cathode ray tube (CRT) as a light source for realizing a digestive image. However, the CRT projection imaging apparatus has limitations in miniaturization and thinning due to the size occupied by the CRT CRT itself, which makes it difficult to realize a large screen display and also makes it difficult to obtain luminance required for high resolution.

In addition to the disadvantages of the CRT display, a projection image device using a flat panel display having a thin thickness and a large screen has been attracting attention. The flat panel display device includes a liquid crystal display (LCD), a plasma display (PDP), a field emission display (FED), an electro-luminescence (EL), and the like.

Projection imaging devices are classified into transmissive and reflective types. Transmissive is a method of transmitting light to various display panels such as LCD, OLED, and FED to enlarge the screen on the screen, and the reflective type is a digital mirroring device (DMD). Or a reflective display panel such as LCOS (liquid crystal on silicon) to reflect and adjust the light projected from the display device to use the screen. In general, the digital light processing (DLP) method digitizes an image signal using such a DMD panel (or DMD device).

Such a reflective projection imaging apparatus projects light from a light source onto a reflective display panel and projects an image of the reflective display panel onto a screen using a projection lens.

A conventional projection system using a reflective reflective display panel is generally composed of a light source system, a reflective display panel, a projection lens system, an optical engine unit composed of a total reflection mirror, and a screen.

The light source system of the optical engine unit generates light to irradiate the reflective display panel. The reflective display panel displays an image by adjusting the transmittance of light incident from the light source system according to the image signal.

In addition, the projection lens system magnifies an image incident from the reflective display panel and projects the image onto a screen so that the viewer can see the screen on the screen.

1 shows the general appearance of such an optical engine. 2 is a cross-sectional view of a side of a projection system using a reflective display panel according to the prior art. Referring to FIG. 2, the projection lens system 50 includes at least one lens group 40 having refractive power between the reflective display panel 20 and the screen 80 and a total reflection mirror 60.

The total reflection mirror 60 is an optical path between the optical axis of the incident light incident from the lens group 40 and a predetermined range of angles formed by the optical axis of the light reflected by the total reflection mirror 60 and emitted to the projection lens 50. To change.

Light generated by the light source 10 is configured to transmit through the prism 30. The prism 30 has a transmission / reflection surface so as to transmit light incident from the light source and reflect light reflected from the reflective display panel and reincident at a predetermined angle.

Light passing through the prism through this path is reflected by the reflective display panel and adjusted by the prism so that the path is directed toward the lens group 40. Light propagated through this path is magnified by the projection lens and projected onto the screen.

On the other hand, in order to project one screen onto the screen without loss, it is necessary to grasp and adjust the distortion characteristics of the light by the length of the optical path, the lens group 40 and the projection lens. In particular, according to the trend that the screen size of the imaging device is becoming very diverse, it is necessary to review and adjust such characteristics in advance.

However, it is very difficult to finely adjust the size of the screen projected on the screen by using the characteristics of the projection lens 50 and the lens 40. Therefore, it may be desirable to adjust the light path to adjust the size of the screen projected on the screen.

With respect to the optical path, referring to FIG. 2, the optical paths from the reflective display panel 20 to the end of the lens group 40 are divided and displayed. Here, the back focal length (BFL) represents the focal length from the reflective display panel to the lens included in the lens group, and the focal length (FL) represents the focal length of the lens itself. According to the prior art, the size of the screen on the screen can be adjusted by adjusting the FL using the optical properties of the lens itself (eg, the magnification of the lens, etc.). However, in addition to the method of adjusting the screen size only by the lens, it is desirable to have various methods for finely adjusting the screen size. If the optical engine is equipped with multiple lenses, it is not easy to adjust the magnification of the lens (i.e., it is not easy to adjust the FL). This can be

The present invention has been proposed to solve the above-mentioned problems of the prior art, and an object thereof is to provide an optical engine capable of easily adjusting the size of the screen projected on the screen by moving the position of the prism.

Other objects and advantages other than the above objects and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

According to a feature of the invention, the optical engine of the present invention comprises a light source (10) for irradiating light, a reflective display panel (20). A prism 30 having a transmissive / reflective surface for transmitting light incident from the light source and reflecting the light reflected from the reflective display panel and reincident at a predetermined angle, on the optical axis of the light exiting through the prism; At least one lens 40 provided, a projection lens 50 for projecting the light passing through the lens on a screen, and a total reflection mirror 60 for reflecting the light from the lens to the projection lens; A prism guide mechanism 70 including a screw, wherein the prism is moved forward and backward in a direction parallel to the optical axis passing through the lens 40 by the prism guide mechanism to adjust the screen size projected on the screen. Adjustment is possible.

In a preferred embodiment according to the above features, the prism guide mechanism of the optical engine of the present invention includes a screw adjustment portion projecting outside the optical engine, through which the adjustment of the position of the prism outside the optical engine is achieved. It is characterized by possible.

In addition, in the preferred embodiment according to the above feature, the optical engine of the present invention is characterized in that the size of the screen projected on the screen can be adjusted not only by adjusting the position of the prism but also by using the characteristics of the lens 40.

According to the present invention, it is possible to more easily adjust the screen size projected on the screen by adjusting the back focal length (BFL).

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

3 is a view showing a BFL adjustable area inside an optical engine viewed from the side according to a preferred embodiment of the present invention. 4 is a schematic illustration of a prism guide mechanism of an optical engine, in accordance with a preferred embodiment of the present invention.

 3 and 4, the optical engine of the present invention includes a prism guide mechanism 70 using a screw. The prism guide mechanism 70 is mounted to the optical engine in contact with the prism and is configured to adjust the BFL while loosening or tightening the screw. That is, when rotating the screw of the screw-type prism guide mechanism, the prism is advanced to change the light reflection position. The prism guide mechanism 70 includes a guide for allowing the prism 30 to move in a constant path inside the optical engine in contact with the prism 30.

With respect to the BFL, the BFL decreases when the screwed prism guide mechanism advances the prism 30 toward the lens 40, and conversely, when the prism 30 moves in the opposite direction to the lens 40, Will increase.

The change of the position of the light reflection through the change of the prism position causes a change in the length of the optical path, and the size of the screen projected on the screen may be adjusted through the change of the length of the optical path.

According to a preferred embodiment, the screw handle 75 of the prism guide mechanism 70 can protrude outside of the optical engine. Therefore, even after the assembly of the optical engine is completed in the manufacturing process, the screen size on the screen can be adjusted using the screw handle 75 protruding outside the engine. After adjusting the position of the prism 30 to optimize the size of the screen projected on the screen to the size of the screen, the optical path is no longer changed by fixing the screwed rod 71 of the prism guide mechanism.

Reference is again made to FIG. 4 to describe one preferred embodiment of the present invention. As shown in FIG. 4, the prism guide mechanism 70 includes a screw-shaped rod 71, a prism support member 72 in contact with the prism 72 and the housing portion 74 of the optical engine, and the rod And a coupling portion 73 which connects the 71 and the housing portion 74 by screwing.

The screwed rod 71 is coupled with the prism support member 72 to enable screw movement. In addition, this screw-shaped rod 71 is supported by a coupling portion 73 (for example, provided in the form of a female screw) connected to the housing portion 74 to screw, so that when screwing, the screw rod It is possible to move back and forth. The prism support member 72 is fixedly coupled to the prism 30 to transmit the moving force of the rod 71 to the prism 30. In addition, the prism support member 72 slides in contact with the housing portion 74 as the rod 71 moves. In one embodiment, between the housing portion 74 and the prism support member 72 may be provided with a sliding groove for setting the movement path of the prism support member. In one embodiment, the prism guide mechanism 70 provides a housing path 74 of the optical engine to provide its path of movement while the prism support member 72 is moving and to provide a screw connection with the rod 71. ) May be provided with a side wall structure separate from.

According to another preferred embodiment, the optical engine of the present invention may use the optical characteristics of the lens as in the prior art for the above-described optical path change. The optical engine of the present invention can adjust the screen size on the screen by adjusting the optical properties of the lens, such as the magnification of at least one lens 40 and / or 50. Therefore, in addition to changing the position of the prism, the FL may be adjusted using the optical characteristics of the lens as in the prior art, and thus, the screen size can be easily adjusted.

As described above, while the present invention has been described with reference to the preferred embodiments, those skilled in the art will understand that changes may be made without departing from the spirit and scope of the invention. In other words, the present invention may be modified within the scope of the appended claims and should not be considered as being limited to the above-described exemplary embodiments.

According to the present invention, it is possible to adjust the screen size projected on the screen more easily by adjusting the back focal length (BFL) without adjusting the FL. Therefore, fine adjustment for fitting the size of the screen projected on the screen to the area of the screen can be easily performed. In addition, these improvements have no effect on optical performance such as brightness and contrast of the screen.

Claims (3)

A light source for irradiating light; A reflective display panel; A prism having a transmissive / reflective surface for transmitting the light incident from the light source and reflecting the light reflected from the reflective display panel and reincident at a predetermined angle; At least one lens provided on an optical axis of light emitted through the prism; A projection lens for expanding and projecting the light passing through the lens onto a screen; A total reflection mirror that reflects the light from the lens to the projection lens; Prism guide mechanism including screws Including, And the prism is capable of front and rear position adjustment in a direction parallel to an optical axis passing through the at least one lens by the prism guide mechanism to adjust the screen size projected on the screen. The optical engine of claim 1, wherein the prism guide mechanism includes a screw adjuster projecting outside the optical engine, and the screw adjuster enables position adjustment of the prism outside the optical engine. The optical engine of claim 1, wherein the screen size is adjustable by the at least one lens.

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