KR200241244Y1 - Front type LCD projector - Google Patents

Abstract

90 ° ± 1 ° between the first optical lens group and the image optical axis passing through the first optical lens group sequentially arranged so as to focus the image light incident from the liquid crystal panel generating the image using the light emitted from the light source A projection lens unit having an optical axis conversion prism formed to be converted between the ranges, and a second optical lens group for focusing and projecting the image light converted by the axis conversion prism on the screen. The front projection type liquid crystal projection device can be used as a wall mount by greatly reducing the set depth.

Description

Front projection type liquid crystal projection device {Front type LCD projector}

The present invention relates to a front projection type liquid crystal projection apparatus for projecting and displaying an image generated by a liquid crystal panel as an image generating source on a front screen, and more particularly, to an optical system of a projection lens unit for projecting an image on a screen. will be.

For example, an image projection apparatus such as a projection television or a video projector enlarges and projects an image generated using an image generating means such as a liquid crystal display (LCD) or a specially made small cathode ray tube (CRT) onto a screen through a projection lens unit. By doing so, a desired image is displayed. Such image projection apparatuses are classified into front type and rear type according to a method of expanding and projecting an image generated by the image generating means onto a screen, as is well known.

1 and 2 respectively show a type of a conventional front projection type liquid crystal projection apparatus, and the liquid crystal projection apparatus shown in FIG. 1 uses a dichroic mirror (11) (12) (13) (14) for color separation. Three liquid crystal panels 15 for separating the white light emitted from the light source 10 into three color wavelengths of red (R), green (G), and blue (B), and generating an image signal corresponding to each color. A so-called three-plate type liquid crystal projection apparatus employing (16) and (17) is shown, and the liquid crystal projection apparatus shown in FIG. 2 employs a single liquid crystal panel 23 having a built-in color filter for color implementation. A so-called single-plate liquid crystal projection device is shown. In FIG. 1, reference numeral 1 denotes a set case, 10 denotes a light source, and 18 and 19 denote reflective mirrors, respectively. In FIG. 2, reference numeral 2 denotes a set case, 20 denotes a light source, 21 denotes a heat ray removing filter, and 22 denotes a reflection mirror.

On the other hand, in each of the conventional front projection type liquid crystal projection apparatus shown in Figs. 1 and 2, an image generated by the liquid crystal panels 15, 16, 17, and 23, which are image generation sources, respectively, is displayed on the front screen. In the optical lens group L incorporated in the projection lens unit 30 for enlarged projection on (S), its optical arrangement structure is arranged in a straight line as shown in FIG. Therefore, the main optical axis of the image light projected by the projection lens unit 30 is emitted in a straight line toward the screen S. According to such a linear optical arrangement structure, since the focus of the image light projected by the projection lens unit 30 should be adjusted to the screen S, the entire set of projection apparatuses is light and thin in accordance with the focal length of the lens group L. There is a limit to digestion. In this case, in particular, the set depths D1 and D2 of the front-projection type liquid crystal projection apparatus are deep, which is not suitable for use in wall-mounting at home.

Therefore, the present invention was devised to improve the problems of the conventional front-projection type liquid crystal projection apparatus as described above, and the object of the present invention is to reduce the overall size of the set of the liquid crystal projection apparatus to light and short, in particular, even for wall hanging It is to provide a slim front projection type liquid crystal projection device for use. This goal can be achieved by reducing the space occupied by the projection lens unit in the projection apparatus set by providing a projection lens unit configured to bend and convert the angle of the image optical axis to shorten the projection distance from the projection lens unit to the screen. Done.

1 is a schematic configuration diagram showing a conventional three-plate type front projection type liquid crystal projection device,

Figure 2 is a schematic configuration diagram showing a conventional single-plate front projection type liquid crystal projection device,

FIG. 3 is a schematic configuration diagram showing an optical arrangement structure of an projection lens unit of the liquid crystal projection apparatus shown in FIGS. 1 and 2;

Figure 4 is a schematic configuration diagram showing a front projection type liquid crystal projection device according to the present invention,

FIG. 5 is a schematic diagram illustrating an optical lens arrangement structure of the projection lens unit of FIG. 4; FIG.

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

200 ... set case 201 ... light source

210 ... LCD panel 220 ... Projection lens unit

L-I ... first optical lens group L-II ... second optical lens group

P ... Prism for optical axis conversion Pi ... Light incident surface

Po ... light slope Pr ... light slope

Po ... light slope Pr ... light slope

P1 ... light reflection prevention thin film layer P2 ... light reflection prevention thin film layer

S ... screen

In order to achieve the above object, the front projection type liquid crystal projection apparatus according to the present invention is a liquid crystal panel as an image source for generating an image by using light emitted from a light source, and the image light generated from the liquid crystal panel on a front screen. A front projection type liquid crystal projection device comprising a projection lens unit for magnifying and projecting, the projection lens unit comprising: a first optical lens group sequentially arranged to focus image light emitted from the liquid crystal panel; Optical path changing means for converting the optical axis of the image light passing through the first optical lens group by converting the optical axis at a predetermined angle; And a second optical lens group for concentrating and projecting the image light whose optical axis is converted by the optical path converting means onto the screen.

In the front projection type liquid crystal projector device according to the present invention, in particular, the optical path converting means is formed for converting the main optical axis of the image light passing through the first optical lens group by bending between 90 ° ± 1 ° range It is preferable that it is a prism.

The liquid crystal panel and the projection lens unit may be moved relative to each other so that the image may be projected on the screen at an arbitrary ratio by adjusting the position of the image light projected on the screen with respect to the main optical axis. Do.

Hereinafter, a front projection type liquid crystal projection apparatus according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

Referring to FIG. 4, the front projection type liquid crystal projection apparatus according to the present invention includes a light source 201 for irradiating light generated by using halogen, xenon, or the like to one side of a substantially rectangular set case 100, and the image source as the image source. The liquid crystal panel 201 that generates an image by using the light emitted from the light source 201 and the main optical axis of the image generated by the liquid crystal panel 210 are converted by bending between 90 ° ± 1 °. It comprises a projection lens unit 220 for projecting on the screen (S) enlarged.

The projection lens unit 220 is a component that characterizes the present invention, and as shown in FIG. 5, a first optical lens in which a plurality of optical lenses are sequentially arranged to focus image light incident from the liquid crystal display device 210. An optical axis converting prism P as an optical path converting means for converting an optical lens group LI, an image optical axis passing through the first optical lens group LI at a predetermined angle, and the optical axis converting prism And a second optical lens group L-II in which a plurality of optical lenses are sequentially arranged to focus the image light whose optical axis is converted by (P) and to project the enlarged image onto the screen S. FIG.

The first optical lens group L-I has a positive power to focus incident light, and includes at least one convex lens L1, a concave lens L2, and an aspherical lens L3.

The second optical lens group L-II has a negative power to diverge and enlarge the focused image, and for this purpose, at least one convex lens L4, meniscus lens L5, and concave lens L6 And an aspherical lens L7, the optical axis of which is coaxial with the optical axis of the first optical lens group LI.

According to the present invention, the optical axis conversion prism (P) and the light incident surface (Pi) and to convert the main optical axis of the image light passing through the first optical lens group (LI) between 90 ° ± 1 ° range Each light exit surface Po is formed to be substantially perpendicular to the main optical axis. Accordingly, the optical axis conversion prism P is formed in a triangle as shown in one side thereof.

In addition, the optical axis conversion prism (P) may be an optical plastic-based material, in order to prevent light reflection on the light incident surface (Pi) and the light exit surface (Po) at least one or more light reflection prevention thin film layer ( P1) can be formed. In addition, any one of the light reflection thin film layers P2 selected from optical aluminum (Al) and silver (Ag) may be formed on the light reflection surface Pr.

According to the front-projection type liquid crystal projection apparatus having the above constitution, the image light formed by the liquid crystal display element 210 is sequentially disposed in the projection lens unit 220, the first optical lens group L-1. After passing through the optical axis converting prism P, the main optical axis is bent in the range of 90 ° ± 1 ° so that its path is changed to pass through the second optical lens group L-2. The image light passing through the second optical lens group L-2 is projected enlarged on the screen S positioned in front, so that a desired image is displayed as an image. As a result, since the focal length of the projection lens unit 220 is substantially shortened and the projection distance of the image light is shortened, the space occupied by the inside of the set case 200 is reduced, so that the depth D3 of the set case 200 is increased. As it is greatly lowered, the overall appearance size becomes slimmer, so that it can be used for wall mounting. For reference, the set depths D1 and D2 of the conventional liquid crystal projection apparatus illustrated in FIGS. 1 and 2 differ greatly from the set depth D3 of the liquid crystal projection apparatus according to the present invention illustrated in FIG. 4. Although not shown in the drawing, the specification is made small in the order of D1 &gt; D2 &gt; D3.

According to another aspect of the present invention, the liquid crystal panel 210 and the projection lens unit 220 may be moved relative to each other so that an image may be projected at an arbitrary ratio in areas A and B of the screen S. The position of the image light projected on the screen S can be adjusted with respect to the main optical axis. In this case, since the projection area of the screen S can be adjusted according to the indoor space in the actual use of the front projection type liquid crystal projection device according to the present invention, a large, medium, or small screen can be configured as necessary. The relative positional movement of the liquid crystal panel 210 and the projection lens unit 220 may adopt various known mechanisms, and for example, the liquid crystal panel with respect to a support frame (not shown) for supporting the liquid crystal panel 210. It is also possible to change the support position of 210.

As described above, the front projection type liquid crystal projection apparatus according to the present invention provides a projection lens unit configured to convert an optical path by bending an angle of an image optical axis to shorten a light projection distance from a projection lens unit to a screen. By reducing the occupied space in the set, the overall dimensions of the set, in particular, the slimmer with a lower depth, can be used for wall mounting.

Claims (5)

A front projection type liquid crystal projection apparatus comprising a liquid crystal panel as an image source for generating an image by using light emitted from a light source, and a projection lens unit for expanding and projecting the image light generated from the liquid crystal panel onto a front screen. The projection lens unit, A first optical lens group sequentially arranged to focus the image light emitted from the liquid crystal panel; Optical path changing means for converting the optical axis of the image light passing through the first optical lens group by converting the optical axis at a predetermined angle; And a second optical lens group for concentrating and projecting the image light whose optical axis is converted by the optical path converting means onto the screen. The method of claim 1, And the optical path converting means is an optical axis converting prism formed to convert a main optical axis of the image light passing through the first optical lens group into a range of 90 ° ± 1 °. The method of claim 2, And a light incident surface and a light emitting surface of the prism for optical axis conversion, respectively, to be perpendicular to the main optical axis. The method of claim 2, The optical axis conversion prism is a front projection type liquid crystal projection device, characterized in that one or more light reflection prevention thin film layer is formed on the light incident surface and the light exit surface. The method of claim 1, The liquid crystal panel and the projection lens unit may be moved relative to each other so that the image may be projected on the screen at an arbitrary ratio by adjusting the position of the image light projected on the screen with respect to the main optical axis. Front projection type liquid crystal projection device.