WO2004099867A1

WO2004099867A1 - Liquid crystal display panel and liquid crystal projector

Info

Publication number: WO2004099867A1
Application number: PCT/KR2004/001091
Authority: WO
Inventors: Soon-Mok Kwon
Original assignee: Iljin Diamond Co., Ltd
Priority date: 2003-05-12
Filing date: 2004-05-12
Publication date: 2004-11-18
Also published as: KR20040097496A

Abstract

The present invention generally relates to a liquid crystal display panel and a liquid crystal projector, and the liquid crystal display panel in accordance with the present invention comprises: a liquid crystal layer formed between an upper substrate and a lower substrate; liquid crystal cells where an anti-dust grass is attached to an upper part of the upper substrate; cases receiving the liquid crystal cells; and metal clips whose one section is connected to the cases and the other section is contacted with edges of the liquid crystal cells, fixing the liquid crystal cells to the cases. And ends of the metal clips slope down at predetermined angles.

Description

Description LIQUID CRYSTAL DISPLAY PANEL AND LIQUID

CRYSTAL PROJECTOR

[i]

Technical Field

[2]

[3] The present invention generally relates to a liquid crystal display panel and a liquid crystal projector, and more specifically, to a liquid crystal display panel and a liquid crystal projector for reducing lightness irradiated per unit surface area of metal clips by sloping the metal clips fixing liquid crystal cells to cases toward a direction in which light is incident on.

Background Art

[4] A liquid crystal projector is a display device using characteristics of a liquid crystal, changing an array of the liquid crystal by applying an electric field to liquid crystal cells formed when injecting the liquid crystal between 2 thin substrates. Light irradiated on a liquid crystal display panel is transmitted or cut off according to array changes of the liquid crystal reacting to the electric field applied outside, thereby forming an image. The formed image is expanded by using an optical system including a projection lens and is projected on a screen.

[5] Generally, the liquid crystal display panel used in the liquid crystal projector is a switching element, cutting off or transmitting light in pixel unit by using a thin film transistor. Such thin film transistor has a fast responsive speed and easily implements high integration.

[6] The liquid crystal display panel consists of the liquid crystal cells for cutting off or transmitting light and cases for fixing positions of the liquid crystal cells. The liquid crystal cells are inserted into the cases, and are fixed to the cases by metal clips.

[7] Fig. 1 is a diagram illustrating a sectional view of a liquid crystal display panel of prior art Referring to Fig. 1, the liquid crystal panel consists of liquid crystal cells and cases(4). The liquid crystal cells are inserted into the cases(4), and are fixed to the cases(4) by metal clips(6).

[8] The liquid crystal cells consist of an upper substrate(l), a lower substrate(2), and a liquid crystal layer(not shown) injected between them. Commonly, the liquid crystal c ells further comprise an anti-dust grass(3-l) attached to an upper part of the upper substrate(l), and comprises an anti-dust grass(3-2) in a lower part of the lower substrate(2) when necessary.

[9] A switching element(commonly, thin film transistor) is formed on the lower substrate(2), a pixel electrode is formed thereon, and a scanning signal and a data signal applied outside are transmitted to the thin film transistor. An opposite electrode opposite to the pixel electrode is comprised on the upper substrate(l). The liquid crystal display panel controls on/off operations of the liquid crystal layer by using an electric field formed by a voltage difference applied between the pixel electrode and the opposite electrode.

[10] The anti-dust grass(3-l) attached to the upper part of the upper substrate(l) prevents foreign substance from being attached to the upper substrate(l), and attaches the foreign substance to the anti-dust grass(3-l) instead of the upper substrate(l), thereby enabling the attached foreign substance to be out of focus on a projection lens. Therefore, the foreign substance is not projected on the projection lens to a degree that the foreign substance is easily seen on a screen. The anti-dust grass(3-2) attached to the lower part of the lower substrate(2) prevents foreign substance from being attached to the lower substrate(2).

[11] Such liquid crystal cells are inserted into the cases(4), and the metal clips(6) are disposed in an upper part thereof. The metal clips(6) are coupled together on sides of the cases(4), and are extended to stretch over edges of the anti-dust grass(301), preventing the liquid crystal cells from being separated from the cases(4).

[12] However, on the prior liquid crystal display panel illustrated in Fig. 1, the metal clips(6) are disposed vertical to incident light, causing a lot of heat since the incident light reaching the metal clips(6) is increased. In consideration of a direction of the incident light, it is known that an area ratio of the metal clips(6) compared to an entire surface area of the anti-dust grass(3-l) is about between 5% and 10% according to manufacturers. Also, the metal clips(6) emit much heat than the liquid crystal cells by the incident light owing to material differences between the metal clips(6) and the liquid crystal cells. Thus, there is a problem of applying much heat to edges of the liquid crystal cells contacted with the metal clips(6).

[13] Furthermore, in case that the light incident at the end of the metal clips(6) is diffusively reflected and the diffusively reflected light is irradiated on an active layer of a thin film transistor, a switching element, there is a possibility of generating an optical leakage current

Disclosure

[14] 1 is therefore an object of the present invention to provide a liquid crystal display panel and a liquid crystal projector for preventing local temperature of metal clips from getting higher through reduction of energy concentrated on the metal clips, by sloping the metal clips for fixing liquid crystal cells to cases toward a direction in which light is irradiated and forming the metal clips with light reflecting materials.

[15] 1 is another object of the present invention to provide a liquid crystal display panel and a liquid crystal projector for preventing light from being diffusively reflected on metal clips.

[16] To accomplish the above object, a liquid crystal display panel in accordance with the present invention comprises: a liquid crystal layer formed between an upper substrate and a lower substrate; liquid crystal cells where an anti-dust grass is attached to an upper part of the upper substrate; cases receiving the liquid crystal cells; and metal clips whose one section is connected to the cases and the other section is contacted with edges of the liquid crystal cells, fixing the liquid crystal cells to the cases. And, ends of the metal clips slope down at predetermined angles

[17] To achieve another object of the present invention, in a liquid crystal projector consisting of at least one light source, a condenser condensing light emitted from the light source, a liquid crystal display panel forming an image by using the light outputted from the condenser, and a projection lens projecting the image formed on the liquid crystal display panel, the liquid crystal display panel comprises: a liquid crystal layer formed between an upper substrate and a lower substrate; liquid crystal cells where an anti-dust grass is attached to an upper part of the upper substrate; cases receiving the liquid crystal cells; and metal clips whose one section is connected to the cases and the other section is contacted with edges of the liquid crystal cells, fixing the liquid crystal cells to the cases. And ends of the metal clips slope down at predetermined angles.

Description Of Drawings

[18] The invention, together with further aspects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:

[19] Fig. 1 is a diagram illustrating a sectional view of a liquid crystal display panel of prior art;

[20] Fig. 2 is a diagram illustrating a sectional view of a liquid crystal display panel in accordance with the present invention;

[21] Fig. 3 is a diagram illustrating that contacted parts of metal clips and liquid crystal cells are expanded; [22] Fig. 4 is a diagram illustrating an optical system of a liquid crystal projector using a liquid crystal display panel in accordance with the present invention; and

[23] Fig. 5 is an explanatory diagram explaining relations between light receiving angles of an A' part of Fig. 3 and inclination angles of metal clips.

Mode for Invention

[24] The present invention will now be described in detail with reference to exemplary preferred embodiments as illustrated in the accompanying drawings.

[25] Fig. 2 is a diagram illustrating a sectional view of a liquid crystal display panel in accordance with the present invention, and Fig. 3 is a diagram illustrating that contacted parts of metal clips and liquid crystal cells are expanded. The present invention will now be described as follows in reference to Fig. 2 and Fig. 3.

[26] The liquid crystal display panel consists of liquid crystal cells and cases(14), and the liquid crystal cells are inserted into the cases(14), and are fixed to the cases(14) by metal clips( 16).

[27] The liquid crystal cells consist of an upper substrate(l 1), a lower substrate(12), and a liquid crystal layer(not shown) injected between them. Commonly, the liquid crystal cells further comprise an anti-dust grass(13-l) attached to an upper part of the upper substrate(l 1), and comprise an anti-dust grass(13-2) in a lower part of the lower substrate(12) when necessary.

[28] A switching element(commonly, thin film transistor) is formed on the lower substrate(12), a pixel electrode is formed thereon, and a scanning signal and a data signal are transmitted to the thin film transistor outside. An opposite electrode opposite to the pixel electrode is comprised on the upper substrate(l 1). The liquid crystal display panel controls on/off operations of the liquid crystal layer by using an electric field formed by voltage differences applied between the pixel electrode and the opposite electrode.

[29] The anti-dust grass( 13-1) attached to the upper part of the upper substrate( 11 ) prevents foreign substance from being attached to the upper substrate(l 1), and attaches the foreign substance to the anti-dust grass(13-l) instead of the upper substrate(l 1), thereby enabling the attached foreign substance to be out of focus on a projection lens. Therefore, the foreign substance is not projected on the projection lens to a degree that the foreign substance is easily seen on a screen. The anti-dust grass(13-2) attached to the lower part of the lower substrate(12) prevents foreign substance from being attached to the lower substrate(12). Like shown in Fig. 2, the anti-dust grasses(13- 1,13-2) are thicker than the upper substrate(l 1) or the lower substrate(12). [30] The liquid crystal display panel(lθ) consisting of the liquid crystal cells and the cases(14) uses the metal clips(16) in order to fix the liquid crystal cells to the cases(14). The metal clips(16) are contacted with edges of the anti-dust grass(13-l) of the liquid crystal cells, fixing the liquid crystal cells to the cases(14). Ends of the metal clips(16) are bent down to slope. Since the ends of the metal clips(16) slope down, lightness irradiated per unit surface area is reduced at the sloping ends of the metal clips(16), compared to ends of prior metal clips(6) illustrated in Fig. 1 that are flatly formed. In addition, it can reduce areas of the metal clips(16) directly contacted with the liquid crystal cells, thereby transmitting a portion of heat only generated from the metal clips(16) to the liquid crystal cells.

[31] Moreover, in case the metal clips(16) are made of light reflecting materials, light irradiated on the metal clips(16) is reflected. Thus, an amount of light energy being converted into heat by reaching the metal clips(16) gets reduced accordingly. The light reflecting materials can include various metal materials such as aluminum, nickel, etc. Like shown in an A' part expressed as a circle in Fig. 3, ends of the metal clips(16) bend down at predetermined angles, thereby reflecting vertically incident light on the metal clips(16). As a result, like shown in Fig. 3, the light proceeds in a direction parallel to surfaces of the liquid crystal cells.

[32] And, a black matrix(17) is located in a line vertically extended toward the liquid crystal cells at the ends of the sloping metal clips(16). Generally, there is a possibility of light irradiated at the ends of the metal clips(16) being diffusively reflected and being irradiated on display regions of the liquid crystal cells.

[33] When the diffusively reflected light is irradiated on wiring units of the display regions, optical leakage currents may be generated in the wiring units, causing a displayed image to be damaged by applying an unexpected electric field to a liquid crystal owing to the generated optical leakage currents. Accordingly, by locating the black matrix(17) in the line vertically extended toward the liquid crystal cells at the ends of the sloping metal clips(16), it is possible for the black matrix(17) to absorb the light diffusively reflected at the ends of the metal clips(16). The black matrix(17) is formed on the upper substrate(l 1) or the lower substrate(12) of the liquid crystal cells, and more desirably, it is formed on the lower substrate(12).

[34] Fig. 4 is a system format diagram of a liquid crystal projector using a liquid crystal display panel in accordance with the present invention, and Fig. 5 is a diagram illustrat ing angles of metal clips in an A' part of Fig. 3 and light receiving angles. The present invention will now be described as follows in reference to Fig. 4 and Fig. 5. [35] An optical system of the liquid crystal projector has a first fly eye lens(21) and a second fly eye lens (hereinafter, 'FEL)(22) and a liquid crystal display panel(lθ).

[36] In the liquid crystal projector, light of a visible ray region emitted from a lamp(30) is reflected by an oval mirror(35), and proceeds toward the first FEL(21). The first FEL(21) divides the incident light in cell unit, and focuses the divided lights in each lens cell of the second FEL(22). The second FEL(22) converts the incident light into parallel light, and enables almost all light emitted from the light source(30) to be incident on the liquid crystal display panel(lθ).

[37] The FEL is a device for condensing light and converting the light into parallel light, and can be replaced with a glass rod condenser, a mirror tunnel condenser, etc.

[38] Since vertically incident light is not irradiated on liquid crystal cells located in lower parts of the sloping metal clips, a shadow is cast Thus, it can protect wiring units installed under a region where the shadow is cast However, if the metal clips do not sufficiently slope down, among light irradiated on the liquid crystal display panel(lθ) from the second FEL(22), light that is not vertically irradiated is irradiated on liquid crystal cell regions located under the sloping metal clips, causing a possibility of producing optical leakage currents in the wiring units of the liquid crystal cells. Therefore, light incident on the wiring units is cut off with the metal clips by properly controlling angles of the sloping metal clips(16).

[39] Fig. 5 is an explanatory diagram for explaining relations between light receiving angles of an A' part of Fig. 3 and inclination angles of metal clips. In Fig 5, a light receiving angle ' 0 1' shows a maximum angle between light incident on liquid crystal cells and a vertical line, and a light receiving angle ' 0 2' illustrates angles at which metal clips(16) bend down from the vertical line. Like shown in Fig. 5, by forming the light receiving angle ' 0 2' bigger than the light receiving angle ' 0 1^* it can cut off light incident on edges of liquid crystal cells by the metal clips(16).

Industrial Applicability

[40] According to a liquid crystal display panel and a liquid crystal projector in accordance with the present invention, metal clips for fixing liquid crystal cells to cases slope at more than predetermined angles, thereby reducing lightness irradiated per unit surface area of the metal clips. Therefore, it can minimize thermal energy produced from the metal clips.

[41] Moreover, since ends of the metal clips are formed in an upper part of a black matrix, the black matrix can absorb diffusively reflected light emitted from the ends of the metal clips. Thus, it can prevent display quality from deteriorating. [42] While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions, and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

[1] A liquid crystal display panel, comprising: liquid crystal cells having a liquid crystal layer between an upper substrate and a lower substrate; cases receiving the liquid crystal cells; and metal clips whose one section is connected to the cases and the other section is contacted with edges of the liquid crystal cells, fixing the liquid crystal cells to the cases, wherein ends of the metal clips slope down at predetermined angles. [2] The liquid crystal display panel of claim 1, wherein thicker glass than the upper substrate is further attached to either one external side of the upper substrate or the lower substrate. [3] The liquid crystal display panel of claim 1, wherein the metal clips are made of light reflecting materials. [4] The liquid crystal display panel of claim 1, wherein angles at which the ends of the metal clips slope toward a vertical line are bigger than light receiving angles at which light incident on the liquid crystal cells slopes toward the vertical line. [5] The liquid crystal display panel of claim 1, wherein the ends of the metal clips are located in an upper region of a black matrix formed on the upper substrate or the lower substrate. [6] In a liquid crystal projector consisting of at least one light source, a condenser for condensing light emitted from the light source, a liquid crystal display panel forming an image by using the light outputted from the condenser, and a projection lens projecting the image formed on the liquid crystal display panel, the liquid crystal display panel, comprising: liquid crystal cells having a liquid crystal layer between an upper substrate and a lower substrate; cases receiving the liquid crystal cells; and metal clips whose one section is connected to the cases and the other section is contacted with edges of the liquid crystal cells, fixing the liquid crystal cells to the cases, wherein ends of the metal clips slope down at predetermined angles. [7] The liquid crystal projector of claim 6, wherein glass thicker than the upper substrate is further attached to at least either one external side of the upper substrate or the lower substrate [8] The liquid crystal projector of claim 6, wherein the metal clips are made of light reflecting materials. [9] The liquid crystal projector of claim 6, wherein angles at which the ends of the metal clips slope toward a vertical line are bigger than light receiving angles at which light incident on the liquid crystal cells slopes toward the vertical line. [10] The liquid crystal projector of claim 6, wherein the ends of the metal clips are located in an upper region of a black matrix formed on the upper substrate or the lower substrate.