Liquid crystal display having dummy bump connected to dummy lead for heat reduction

A liquid crystal display for use in a LCD projector includes a liquid crystal display panel including a TFT substrate, a counter substrate, and liquid crystal interposed between the TFT substrate and the counter substrate; a flexible film substrate being electrically coupled to the liquid crystal display panel and having a plurality of leads including at least one dummy lead; and a driving IC for driving the liquid crystal display panel, the driving IC being disposed on the film substrate and having at least one dummy bump. The dummy bump is connected to the dummy lead, and the dummy lead has a heat releasing function.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention contains subject matter related to Japanese Patent Application JP 2004-196217 filed in the Japanese Patent Office on Jul. 2, 2004, Japanese Patent Application JP 2004-196218 filed in the Japanese Patent Office on Jul. 2, 2004, and Japanese Patent Application JP 2004-197691 filed in the Japanese Patent Office on Jul. 5, 2004, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to liquid crystal displays for use in liquid crystal display (LCD) projectors.

2. Description of the Related Art

LCD projectors that operate by selectively transmitting light from a light source using liquid crystal displays and then throwing the transmitted light onto a screen to deliver images on large-screens have gained popularity in recent years. The liquid crystal displays incorporated in these LCD projectors typically include internal driving circuits. These liquid crystal displays use polycrystalline silicon thin-film transistors (hereinafter, polysilicon TFTs), produced by high-temperature processes, instead of amorphous silicon films, since such polysilicon films have high electron mobility.

Demands for higher precision, higher aperture ratios, and lower cost have been increasingly placed on the liquid crystal displays for use in LCD projectors. In response to these needs, a proposal of external driving circuits has been made (for example, Japanese Unexamined Patent Application Publication No. 2003-332585). This proposal corresponds with trends of other liquid crystal devices in which external driving circuits are used instead of internal driving circuits. In detail, a driver IC, for driving a liquid crystal display panel, is provided separate from the liquid crystal display panel including effective pixels to thereby increase the effective pixel area of the liquid crystal display panel and to increase the number of the liquid crystal display panels that can be produced from one mother substrate. Furthermore, higher precision, higher aperture ratios, and lower cost can be achieved according to this structure.

SUMMARY OF THE INVENTION

In the LCD projectors, however, light having a high intensity of about 40,000,000 lux in terms of white light is incident on the liquid crystal display panels of the projectors. The incidence of such intense light increases the temperature around the liquid crystal display panels, in particular, the temperature of the driver ICs. Moreover, the driver ICs generate heat by operation (energization). The increase in temperature of the driver ICs may result in driver malfunction, degraded image quality resulting from the malfunction and the temperature increase, and low reliability of the liquid crystal displays.

In order to comply with the needs of higher precision, higher aperture ratios, and lower cost, it is desirable to provide a liquid crystal display, which has an external driving IC separate from the liquid crystal display panel and which can reduce malfunction and prevent a decrease in image quality and reliability by effectively controlling the temperature increase in the driving IC.

An embodiment of the present invention provides a liquid crystal display for use in a LCD projector for projecting an enlarged image and for optically modulating light emitted from a light source of the LCD projector. The liquid crystal display includes a liquid crystal display panel including a TFT substrate, a counter substrate, and liquid crystal interposed between the TFT substrate and the counter substrate; a flexible film substrate being electrically coupled to the liquid crystal display panel and having a plurality of leads including at least one dummy lead; and a driving IC for driving the liquid crystal display panel, the driving IC being disposed on the film substrate and having at least one dummy bump. The dummy bump is connected to the dummy lead, and the dummy lead has a heat releasing function.

Here, the term “dummy bump” refers to a bump not contributing to the driving of the liquid crystal display panel. The number of dummy bumps may be any. The term “dummy lead” refers to a lead not necessary for driving of the liquid crystal display panel. The phrase “having a heat releasing function” means that the component has heat conductivity and is capable of transferring the heat in the dummy lead to the ambient air or another component connected thereto. According to the liquid crystal display described above, the heat generated in the driving IC is transferred to the dummy lead through the dummy bump and is released from the dummy lead. Thus, the temperature increase in the driving IC can be suppressed.

Another embodiment of the present invention provides another liquid crystal display for use in a LCD projector for projecting an enlarged image and for optically modulating light emitted from a light source of the LCD projector. The liquid crystal display includes a liquid crystal display panel including a TFT substrate, a counter substrate, and liquid crystal interposed between the TFT substrate and the counter substrate; a support including a frame for supporting the liquid crystal display panel; a flexible film substrate being electrically coupled to the liquid crystal display panel; and a driving IC for driving the liquid crystal display panel. The driving IC is disposed on the flexible film substrate, and the position of the driving IC is distant from an outer edge of the support in an outward direction.

With this structure, the driving IC is exposed outside the support and not covered with the support. As a consequence, the heat generated in the driving IC can be easily released to the outer side of the support, i.e., to the exterior of the liquid crystal display. Moreover, it becomes possible to position the driving IC on the passage of the cooling air. Thus, the driving IC can be efficiently cooled, and the temperature increase in the driving IC can be effectively suppressed.

Yet another embodiment of the present invention provides another liquid crystal display for use in a LCD projector for projecting an enlarged image and for optically modulating light emitted from a light source of the LCD projector. The liquid crystal display includes a liquid crystal display panel including a TFT substrate, a counter substrate, and liquid crystal interposed between the TFT substrate and the counter substrate; a driving IC for driving the liquid crystal display panel, the driving IC being disposed on one of the substrates; and light-shielding means for shielding light entering the driving IC.

With this structure, the light-shielding means blocks the light from the light source of the LCD projector and prevents light from the light source from directly entering the driving IC. Thus, the temperature increase and the generation of carriers are prevented in the driving IC.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention will be described below with reference to the drawings. In the description below, the identical components are represented by the same reference numerals.

First Embodiment

A LCD projector incorporating liquid crystal displays is first described. A three-panel liquid crystal display (LCD) projector that includes three liquid crystal displays respectively having panels of red, green, and blue is widely known.FIG. 1is a diagram showing the configuration of a three-panel LCD projector.

Referring toFIG. 1, light emitted from a light source1passes through a filter2athat cuts infrared and UV rays, a fly-eye lens2b, and a PS splitter/synthesizer for converting unpolarized light to polarized light, and is split into R, G, and B light beams with dichroic mirrors3that each reflect only a light beam in a particular wavelength region. The RGB light beams respectively enter liquid crystal displays6R,6G, and6B via total reflection mirrors4and a condenser lens5where necessary, and modulated according to image signals in the liquid crystal displays6R,6G, and6B. The modulated light beams are combined with a dichroic prism7and enlarged with a projection lens8to project an enlarged color image onto a screen.

The liquid crystal displays6R,6G, and6B will now be described with reference toFIGS. 2 to 7showing various examples of liquid crystal displays of this embodiment.

As shown inFIGS. 2 and 3, the liquid crystal display includes a liquid crystal display panel10, a frame20, and a light-shielding panel30. The frame20is disposed at the outgoing-light-side of the liquid crystal display panel10and provides support for the liquid crystal display panel10. The frame20may be composed of a metal material, such as aluminum magnesium or stainless steel, having high thermal conductivity, or a resin material having high thermal conductivity. The light-shielding panel30is disposed at the incident-light-side of the liquid crystal display panel10to prevent light from entering the region other than the effective pixel region. The light-shielding panel30may be a metal or resin plate with high thermal conductivity, having an opening that corresponds to the effective pixel region. Alternatively, the light may be incident in the opposite direction.

The liquid crystal display panel10includes a TFT substrate11, a counter substrate12, and liquid crystal (not shown) interposed between the TFT substrate11and the counter substrate12. The TFT substrate11has TFTs, which serve as pixel electrodes constituting pixels, arranged in a matrix. The counter substrate12has a counter or common electrode. According to this structure, liquid crystal directors orient in the same direction by the application of voltage between the opposing electrodes of the liquid crystal display panel10, thereby generating uniaxial birefringence anisotropy. As a result, the amount of transmitted light can be controlled, and light from the light source1can be optically modulated based on the image signals. At the incident light-side and the outgoing light-side of the liquid crystal display panel10, two cover glasses13are respectively provided to protect the TFT substrate11and the counter substrate12.

In order to meet the needs of higher precision, higher aperture ratios, and lower cost, the liquid crystal display panel10does not include a driving circuit for applying voltage to the electrodes on the TFT substrate11and the counter substrate12to drive the liquid crystal display panel10. Instead, a flexible film substrate14electrically coupled to the respective electrodes on the TFT substrate11and the counter substrate12is attached to the liquid crystal display panel10, and a driving IC15, for driving the liquid crystal display panel10, is disposed on the flexible film substrate14. The structures of the flexible film substrate14and the driving IC15may be any, and the detailed description therefor is omitted since they are already well known in the related art.

The structure of the liquid crystal display shown inFIG. 3, including the liquid crystal display panel10and the external driving IC15provided on the flexible film substrate14, is called a “chip-on-film” (COF) structure. With the COF structure, the effective pixel area in the liquid crystal display panel10can be increased and the number of the liquid crystal display panels10produced from a mother substrate can be easily increased since the driving IC15is provided separate from the liquid crystal display panel10. Thus, higher precision, higher aperture ratios, and low cost can be realized. The driving IC15disposed on the flexible film substrate14contributes to reducing the size of the substrates11to13of the liquid crystal display panel10and offers greater flexibility to layout designing.

The features of the flexible film substrate14and the driving IC15will now be described in detail.

Referring toFIGS. 4A and 4B, the driving IC15is mounted onto the flexible film substrate14with a plurality of bumps16by a flip-chip technique, and the connecting part is embedded in an underfill17, e.g., a non-conductive paste, an anisotropic conductive film, or an anisotropic conductive paste. For example, as shown inFIG. 5, at least one of the bumps16is a dummy bump16a. The term “dummy bump” refers to a bump not contributing to the driving of the liquid crystal display panel10by the driving IC15, i.e., a bump that does not need to be electrically connected to the driving IC15. The number of dummy bumps16amay be any.

The flexible film substrate14, onto which the driving IC15is formed, includes a base film14a, a cover film14b, and a plurality of leads18interposed between the base film14aand the cover film14b. The leads18are arranged parallel to each other at a pitch corresponding to the pitch between the bumps16of the driving IC15. At least one of the leads18is a dummy lead18a, and the dummy lead18aconnects to the dummy bump16aof the driving IC15. The term “dummy lead” refers to a lead not necessary for driving of the liquid crystal display panel as with the dummy bump. The dummy lead has a heat releasing function. Here, “heat releasing function” means that the dummy lead18ahas thermal conductivity and a capability to transfer heat in the dummy lead18ato ambient air of the dummy lead18aor to a component (e.g., to a circuit substrate connected to the flexible film substrate14) connected to the dummy lead18a. As with the dummy bump16a, the number of the dummy leads18amay be any. The number of the dummy leads18amay not be the same as the number of the dummy bump16a. A plurality of the dummy bumps16amay be connected to one dummy lead18a.

In this liquid crystal display having the above-described configuration, heat generated in the driving IC15is transferred to the dummy lead18avia the dummy bump16aand is released from the dummy lead18a. It is a widespread practice to provide a dummy bump16ato mount the driving IC15on a substrate in a balanced fashion. In this embodiment, the dummy bump16ais connected to the dummy lead18aso that the dummy lead18acan be used to release heat generated from the driving IC15.

Thus, a LCD projector equipped with this liquid crystal display having a COF structure can meet the demands for higher precision, higher aperture ratios, low costs, and the like, and rarely suffers from malfunction resulting from a temperature increase since the heat dissipation from the dummy lead18asuppresses a temperature increase in the driving IC15. Moreover, this structure prevents inappropriate optical modulation in the liquid crystal display panel10by the malfunction, i.e., the degradation in the quality of the image displayed. Furthermore, the degradation in image quality resulting from heat transferred from the driving IC15to the liquid crystal display panel10can be reduced. According to the liquid crystal display described herein, the reliability of the driving IC15, i.e., the driving circuit of the liquid crystal display panel10, can be improved as well as the reliability of the liquid crystal display. Since no special elements are necessary, higher reliability can be achieved without increasing the cost.

In the flexible film substrate14, the dummy lead18ais preferably at an end of the row of the leads18on the flexible film substrate14. Since the dummy bump16aof the driving IC15is frequently located at an end of the driving IC15, such an arrangement of the dummy lead18aincreases the flexibility of designing the shape of the dummy lead18a.

To be more specific, the line width and the area of the dummy lead18acan be increased compared to those of the other leads18if the dummy lead18ais positioned at the end of the row of the leads18, as shown inFIG. 5. The dummy lead18ahaving this shape can satisfactorily release heat and is thus suitable for releasing heat from the driving IC15.

Another example of the arrangement is shown inFIG. 6. In this example, the dummy lead18ahas a portion having a line width equal to that of the other leads18and a portion having a line width larger than that of the other leads18, thereby having an increased average line width. Since the average line width of the dummy lead18ais increased, heat can be released more effectively and the arrangement of the flexible film substrate14, layouts of the leads, positions of the bumps of the driving IC15, and the like can be designed with greater flexibility.

Another way of increasing the heat dissipation from the dummy lead18ais to not cover the dummy lead18awith the cover film14b. For example, as shown inFIG. 7, only the leads18, but not the dummy lead18a, are covered with the cover film14b. Since the dummy lead18ais exposed, heat can be released more efficiently. It is also possible to provide cooling air to the exposed dummy lead18afrom a blower fan to achieve a higher heat dissipation effect. Thus, the dummy lead18anot covered with the cover film14bis more suitable for releasing heat from the driving IC15. This arrangement is easily realized by positioning the dummy lead18aat the end of the row of the leads18.

Other examples of the liquid crystal display will now be described.FIGS. 8A to 9Bare cross-sectional partial views of liquid crystal displays.

The liquid crystal display shown inFIGS. 8A and 8Bhas the frame20, which supports the liquid crystal display panel10, in contact with the dummy lead18athrough a heat conductive resin50. In detail, the portion of the flexible film substrate14corresponding to the frame20is not covered with the cover film14b, and the dummy lead18ain this uncovered portion comes into contact with the frame20via the heat conductive resin50.

The liquid crystal display shown inFIGS. 9A and 9Bhas the light-shielding panel30, which shields light entering to regions other than the effective pixel region of the liquid crystal display panel10, in contact with the dummy lead18athrough the heat conductive resin50. In detail, the portion of the flexible film substrate14corresponding to the peripheral region of the light-shielding panel30is not covered with the cover film14b, and the dummy lead18ain this uncovered portion comes into contact with the dummy lead18avia the heat conductive resin50.

According to the structures shown inFIGS. 8A to 9B, the heat generated in the driving IC15can be transmitted to either the frame20or the light-shielding panel30via the dummy bump16aand the dummy lead18a. Thus, in addition to the dummy lead18a, the frame20and the light-shielding panel30can also be used to release heat generated in the driving IC15. Thus, the temperature increase of the driving IC15can be suppressed, and the malfunction of the driving IC15can be more reliably prevented.

Preferably, the heat conductive resin50is provided between the dummy lead18aand the frame20and between the dummy lead18aand the light-shielding panel30to transmit heat from the driving IC15via the frame20and the light-shielding panel30. The heat conductive resin50is elastic and can thus absorb the difference in linear expansion coefficient between the flexible film substrate14and the frame20and between the flexible film substrate14and the light-shielding panel30, in case the flexible film substrate14, the frame20, and the light-shielding panel30have different linear expansion coefficients. Thus, separation of the components can be prevented, and the heat generated in the driving IC15can be reliably transmitted to the frame20and the light-shielding panel30. Examples of the heat conductive resin50include a heat-conducting sheet based on an acrylic rubber or ethylene-propylene rubber (e.g., TM Sheet EP produced by F-CO Co., Ltd.) and an insulating resin material having a high heat conductivity (e.g., CN-733 produced by MERECO).

Second Embodiment

A liquid crystal display according to a second embodiment will now be described. The liquid crystal display of the second embodiment is shown inFIG. 10. The driving IC15is located distant from the outer edge of the support of the liquid crystal display panel10, by a distance A in the outward direction.

The term “support” here refers to a component that supports the liquid crystal display panel10. In particular, the frame20and the light-shielding panel30may each function as a support. Referring toFIG. 11, when the frame20is attached to a mounting board40so that the liquid crystal display can be attached to a dichroic prism (not shown), the mounting board40also function as a support. In this example, the driving IC15is located distant from the outer edge of the conductive pattern40by a distance B in the outward direction.

The phrase “distant from the outer edge of the support in the outward direction” means that the component is outside the region defined by the outline (outer shape in a plan view) of the support viewed in the direction of light incident on the liquid crystal display. In other words, as shown inFIG. 12A, the component is at the side remote from an effective pixel region16with reference to the outline of the support. The outline of the support is not limited to a rectangular shape shown inFIG. 12A. The outline may have a cutout portion21, as shown inFIG. 12B. In such a case, a position inside the cutout portion21is also “distant from the outer edge of the support in the outward direction”.

When the driving IC15is located distant from the outer edge of the support in the outward direction, the driving IC15is exposed and is not covered with the support such as frame20or the light-shielding panel30. Thus, the heat generated in the driving IC15can easily be released.

Moreover, it also becomes possible to cool the driving IC15itself. A typical LCD projector is equipped with a blower fan and thus air flows around the liquid crystal display, as shown inFIG. 13. The driving IC15distant from the outer edge of the support is located on the air passage; hence, it is possible to cool the driving IC15with the air from the fan.

According to the liquid crystal display described above, heat can be easily released from the driving IC15, and the driving IC15itself can be cooled. Thus, the temperature increase in the driving IC15can be suppressed. A LCD projector equipped with this liquid crystal display having a COF structure can meet the demands for higher precision, higher aperture ratios, low costs, and the like, and rarely suffers from malfunction of the driving IC15resulting from increased temperature. Moreover, this structure prevents inappropriate optical modulation in the liquid crystal display panel10by malfunction, i.e., the degradation in the quality of the image displayed. Furthermore, the degradation in image quality resulting from heat transferred from the driving IC15to the liquid crystal display panel10can be reduced. According to the liquid crystal display described herein, the reliability of the driving IC15, i.e., the driving circuit of the liquid crystal display panel10, can be improved as well as the reliability of the liquid crystal display. Since no special elements are necessary, higher reliability can be achieved without increasing the cost.

The driving IC15is preferably disposed at the outgoing light-side of the flexible film substrate14so that light is not directly incident on the driving IC15. This is because, compared to a case where the driving IC15is disposed at the incident light-side of the flexible film substrate14, the possibility of light (diffracted light and the like) entering the driving IC15can be decreased. When the light incident on the driving IC15is decreased, the temperature of the driving IC15can be prevented from increasing and malfunction of the TFTs caused by carriers generated by the incident light can be prevented.

Next, other examples of the liquid crystal displays of this embodiment will be described with reference toFIGS. 14A to 14C.FIGS. 14A to 14Care partial diagrams for explaining the other examples of the liquid crystal display of this embodiment.

As shown in the drawings, the driving IC15is not covered with the support, and the flexible film substrate14has bending points. With these structures, the driving IC15on the flexible film substrate14is offset in directions parallel to the direction of the light incident on the liquid crystal display panel10. The offset amount is preferably at a level at which the driving IC15is distant from the outer edge of the support in the outward direction.

Here, the phrase “distant from the outer edge of the support in the outward direction” means that the component is at the incident light-side with respect to the end face of the support disposed at the incident light-side of the liquid crystal display or that the component is at the outgoing light-side with respect to the end face of the support disposed at the outgoing light-side of the liquid crystal display. To be more specific, the driving IC15may be at the outgoing light-side with respect to the frame20, i.e., the support, as shown inFIG. 14A; the driving IC15may be at the incident light-side with respect to the light-shielding panel30, i.e., the support, as shown inFIG. 14B; or the driving IC15may be at the outgoing light-side with respect to the mounting board40, as shown inFIG. 14C.

The driving IC15at an offset position is located on the passage of air delivered by the blower fan of the LCD projector. Thus, the cooling air can be supplied to the driving IC15to thereby reliably cool the driving IC15.

When the driving IC15is disposed at an offset position, it is preferable to fix the vicinity of the driving IC15onto the support. In particular, the portion near the driving IC15may be fixed onto the frame20, as shown inFIG. 14A, onto the light-shielding panel30, as shown inFIG. 14B, or onto the mounting board40, as shown inFIG. 14C. The flexible film substrate14is typically a flexible film having a thickness of about 100 to about 200 μm. Thus, when cooling air is blown toward the driving IC15at an air velocity of about 5 to 7 m/s, the flexible film substrate14will vibrate, thereby increasing the risk of disconnection and increased noise. By fixing the portion of the flexible film substrate14near the driving IC15, which is the largest component on the flexible film substrate14, vibration of the flexible film substrate14resulting from blown air can be suppressed, and the risk of disconnection and increased noise can be avoided.

The flexible film substrate14may be fixed onto the support via the heat conductive resin50. The heat conductive resin50may be, for example, an acrylic rubber- or ethylene-propylene-based heat conducting sheet (e.g., TM Sheet EP produced by F-CO Co., Ltd.) or an insulating resin material having a high heat conductivity (e.g., CN-733 produced by MERECO). Such a resin has both elasticity and heat conductivity.

By fixing the flexible film substrate14onto the support using the heat conductive resin50, heat generated in the driving IC15is transmitted to the support via the flexible film substrate14and the heat conductive resin50. Thus, the support, such as the frame20, the light-shielding panel30, and the mounting board40, can be used to release heat, and the temperature increase in the driving IC15can be reliably suppressed. Moreover, the interposed heat conductive resin50is elastic and thus absorbs the difference in thermal strain between the two components having different linear expansion coefficients. Thus, the flexible film substrate14does not detach from the support.

Another example of the liquid crystal display of this embodiment is described below with reference toFIG. 15.FIG. 15is a partial diagram for explaining another example of the liquid crystal display.

As shown inFIG. 15, the driving IC15of this liquid crystal display is not covered with the support but is attached to a heat sink71. The heat sink71is a device (radiator) for releasing the heat generated in the driving IC15to the exterior. The heat sink71is a metal component with many fins for increasing the surface area. The heat sink71may be attached onto the chip surface of the driving IC15via a heat conducting resin similar to the heat conductive resin50. The heat conducting resin can absorb the difference in linear expansion coefficient between the driving IC15and the heat sink71.

The heat sink71helps release the heat of the driving IC15with high efficiency, thereby securing further suppression of the temperature increase of the driving IC15. The driving IC15may be provided with the heat sink71and at the same time disposed at an offset position, as described above. With this structure, the temperature increase of the driving IC15will be further suppressed.

Third Embodiment

A liquid crystal display of a third embodiment will now be described with reference toFIGS. 16A and 16B. The liquid crystal display includes the liquid crystal display panel10, the frame20, and the light-shielding panel30. The frame20is disposed at the outgoing light-side of the liquid crystal display panel10and functions as a support of the liquid crystal display panel10. The frame20may be composed of a metal material, such as aluminum, magnesium, or stainless steel, having high heat conductivity, or a resin having high heat conductivity. The light-shielding panel30is disposed at the incident light-side of the liquid crystal display panel10and shields light entering the region outside the effective pixel region. The light-shielding panel30may be a metal or resin plate with high heat conductivity having an opening corresponding to the effective pixel region.

The detailed structure and the operation of the liquid crystal display panel10are the same as those of the first embodiment described above. Thus, the description therefor is omitted here to avoid redundancy.

The liquid crystal display of this embodiment also has a driving circuit outside the liquid crystal display panel10. However, in this embodiment, the flexible film substrate14for receiving signals from a parent device (e.g., a controller of the LCD projector) and the driving IC15for driving the liquid crystal display panel10are disposed on the TFT substrate11of the liquid crystal display panel10. The driving IC15is electrically connected to the respective electrodes of the TFT substrate11and the counter substrate12to thereby drive the liquid crystal display panel10. Alternatively, the driving IC15may be mounted on the counter substrate12instead of the TFT substrate11. In other words, the driving IC15may be mounted on any one of the substrates that constitute the liquid crystal display panel10. The detailed description of the flexible film substrate14and the driving IC15are omitted here since it is already provided in the related art.

In this liquid crystal display, the driving IC15is separate from the liquid crystal display panel10but disposed on one of the substrates of the liquid crystal display panel10. This structure is known as chip-on-glass (COG) structure. According to the COG structure, the effective pixel area in the liquid crystal display panel10can be increased and the number of the liquid crystal display panels10produced from a mother substrate can be easily increased since the driving IC15is provided separate from the liquid crystal display panel10. Thus, higher precision, higher aperture ratios, and low cost can be realized. Since the driving IC15is disposed near on the TFT substrate11, for example, i.e., near the respective electrodes, the responsiveness in driving the liquid crystal display panel10is increased, vibration of the driving IC15can be reduced, and a more stable operation becomes possible.

The feature of this liquid crystal display is the positional relationship between the driving IC15and the frame20. In particular, as shown inFIGS. 16A and 16B, the driving IC15is covered with one component at the incident light-side selected from the frame20and the light-shielding panel30or more preferably covered with both the frame20and the light-shielding panel30. In other words, one or, preferably, both of the frame20and the light-shielding panel30are extended beyond the driving IC15.

With this structure, the light emitted from the light source1of the LCD projector is shielded by the frame20or the light-shielding panel30and does not directly enter the driving IC15. Thus, the frame20and/or the light-shielding panel30functions as a shielding member for shielding light entering the driving IC15.

Accordingly, a temperature increase of generation of carriers caused by light incident on the driving IC15can be prevented. Thus, a LCD projector equipped with this liquid crystal display having a COF structure can meet the demands for higher precision, higher aperture ratios, low costs, and the like, and rarely suffers from malfunction of the driving IC15resulting from the light incident on the driving IC15. This structure prevents inappropriate optical modulation in the liquid crystal display panel10by the malfunction, i.e., the degradation in the quality of the image displayed. According to the liquid crystal display described herein, the reliability of the driving IC15, i.e., the driving circuit of the liquid crystal display panel10, can be improved along with the reliability of the liquid crystal display.

In particular, when both the frame20and the light-shielding panel30function as light-shielding components, not only light directly incident from the light source1, but also the diffracted or reflected light, can be prevented from entering the driving IC15. In this manner, the malfunction of the driving IC15resulting from incident light can be more securely prevented.

Moreover, no additional component is necessary since the frame20and the light-shielding panel30are used to shield light. Thus, the reliability can be improved without increasing the cost.

Alternatively, as shown inFIGS. 17A to 17C, it is possible to provide an additional resin component16at a position corresponding to the driving IC15. The resin component16may be any component having a light-shielding property, an insulating property, and elasticity. Examples thereof include room temperature-vulcanizable (RTV) silicone rubbers. The resin component16may cover the driving IC15, as shown inFIG. 17A, may be disposed at the back of the TFT substrate11remote from the driving IC15, as shown inFIG. 17B, or may cover the driving IC15provided with an insulating film70(SiO2/SiN, or the like) on its surface, as shown inFIG. 17C.

In order to shield light at both the incident light-side and the outgoing light-side, as shown inFIGS. 18A to 18F, the resin component16may be used in combination with one of the frame20and the light-shielding panel30or two resin components16may be respectively disposed on the two surfaces of the TFT substrate11. With the resin component16, light entering the driving IC15can be easily shielded without complicating the shape of the frame20or the light-shielding panel30.

Other examples of the liquid crystal display of this embodiment will now be described.FIGS. 19A to 21Bare cross-sectional views showing the other examples of the liquid crystal display of this embodiment.

The light-shielding component of the liquid crystal display described here not only shields light entering the driving IC15, but also releases heat generated in the driving IC15via the portion connected to the surface of the driving IC15. As shown inFIGS. 19A and 19B, the driving IC15is connected to either the frame20(FIG. 19A) or the light-shielding panel30(FIG. 19B) that functions as the light-shielding component.

This structure allows the heat generated in the driving IC15to be transmitted to the frame20or the light-shielding panel30, thereby releasing the heat from the driving IC15. Accordingly, the temperature increase of the driving IC15can be suppressed, the light from the light source1can be adequately shielded, and the malfunction of the driving IC15can be securely prevented.

As shown inFIGS. 19A and 19B, the heat conductive resin50is preferably interposed between the driving IC15and the frame20or between the driving IC15and the light-shielding panel30to absorb the difference in linear expansion coefficient between the driving IC15, the frame20, and the light-shielding panel30and to thereby prevent detachment of the components. Examples of the heat conductive resin50are the same as those described in the second embodiment.

The frame20or the light-shielding panel30to which the driving IC15is to be connected preferably has a processed portion to increase the area attached to the surface of the driving IC15, as shown inFIGS. 20A to 21B. Examples of the processed portion include a groove such as a groove21shown inFIG. 20A, a projection such as a projection22show inFIG. 20B, and bent portions such as bent portions31shown inFIGS. 21A and 21B. The processed portion is not limited to these and may be of any shape that increases the area of the connection (e.g., corrugated portion). The processed portion that increases the area of the connection can improve the efficiency of heat transmission and effectively suppresses the temperature increase of the driving IC15.