JP2007187753A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device that can be made small with less heat generation and less noise, and can capture images with high resolution. <P>SOLUTION: The liquid crystal display is used which is equipped with a liquid crystal display panel 2; an image pickup unit 4, having an imaging optical system; a detection light source unit 9 which emits detection light, having wavelength in the IR region toward the observer's side of the liquid crystal display panel 2; and a backlight device 5. The backlight device 5 includes a light source 6 and an optical layer 7 and is disposed to leave a space 25 from the liquid crystal display panel 2. The imaging unit 4 is disposed inside the backlight device 5 and receives the detection light, passing from the observer's side through the liquid crystal display panel 2 and images the state of the liquid crystal display panel on the observer side. A fluorescent member 12, which transmits the detection light, is disposed in a region of the optical layer 7 overlapping the optical path of the detection light to be received by the imaging unit 4. The fluorescent member 12 absorbs excitation light and emits visible light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device provided with an image input function.

  In recent years, in the field of display devices, display devices having an input function in addition to a display function have become widespread. An example of such a display device is a display device with a touch panel (see, for example, Patent Document 1). The display device disclosed in Patent Document 1 guides light emitted from a projector to a display area, and receives light reflected by a user's finger placed on the display area among the guided light by a CCD camera. The touch position is detected by.

In addition to a display device with a touch panel, a liquid crystal display device configured to be able to capture an image itself is also disclosed (see, for example, Patent Document 2). The display device disclosed in Patent Document 2 includes a plurality of photodiodes arranged in a matrix on an active matrix substrate, thereby capturing an image of an object on a display screen.
JP 2001-350586 A (FIG. 1) JP 2004-159273 A (FIGS. 2 to 3)

  However, in the display device disclosed in Patent Document 1, since it is necessary to use a projector, there are a problem that the noise caused by the power supply fan is large, a problem that the heat generation amount is large, and a problem that the entire apparatus cannot be reduced in size.

  Further, the display device disclosed in Patent Document 2 has a configuration that enables capturing of an image, but does not include an imaging optical system. Therefore, in the display device disclosed in Patent Document 2, a clear captured image is obtained. It is impossible to get. The display device disclosed in Patent Document 2 has a problem that it is impossible to capture high resolution.

  An object of the present invention is to provide a liquid crystal display device that solves the above-mentioned problems, generates a small amount of heat, can be reduced in size and size, and can capture a high-resolution image.

  In order to achieve the above object, a liquid crystal display device according to the present invention provides a liquid crystal display panel, an imaging unit having an imaging optical system, and detection light having a wavelength in the infrared region to the viewer side of the liquid crystal display panel. A detection light source unit that emits light, and a backlight device that illuminates the liquid crystal display panel from the back side. The backlight device includes a light source and an optical layer disposed on the liquid crystal display panel side of the light source. And the liquid crystal display panel is disposed so that a space exists between the liquid crystal display panel, the imaging unit is disposed inside the backlight device, and is incident on the liquid crystal display panel from an observer side, and By receiving the detection light passing through the liquid crystal display panel and the imaging optical system, the state of the liquid crystal display panel on the observer side is imaged, and the optical layer of the backlight device is captured on the optical layer. A fluorescent member is provided in a region overlapping with the optical path of the detection light received by the imaging unit, and the fluorescent member transmits the detection light and emits visible light by excitation. And

  As described above, according to the liquid crystal display device of the present invention, since an image can be displayed using a liquid crystal display panel, it is possible to achieve a reduction in heat generation, noise reduction, and size reduction. Furthermore, in the liquid crystal display device according to the present invention, since the imaging unit includes an imaging optical system, it is possible to capture a high-resolution image as compared with a display device having a conventional input function.

  A liquid crystal display device according to the present invention includes a liquid crystal display panel, an imaging unit having an imaging optical system, a detection light source unit that emits detection light having a wavelength in the infrared region to the viewer side of the liquid crystal display panel, A backlight device that illuminates the liquid crystal display panel from the back side, and the backlight device includes a light source and an optical layer disposed on the liquid crystal display panel side of the light source, and the liquid crystal display panel The imaging unit is disposed inside the backlight device and is incident on the liquid crystal display panel from the viewer side, and the liquid crystal display panel and the connection are arranged. By receiving the detection light passing through the image optical system, the state of the liquid crystal display panel on the observer side is imaged and received by the imaging unit in the optical layer of the backlight device. That the the region which overlaps with the optical path of the detection light, fluorescent member is provided, the fluorescent member may not transmit the detection light, and characterized in that it emits visible light excitation.

  With the above characteristics, the liquid crystal display device according to the present invention can reduce the amount of heat generation, reduce the noise, and reduce the size, and can capture a high-resolution image. Further, in the liquid crystal display device according to the present invention, the imaging unit arranged inside the backlight device is covered with a fluorescent member provided in the optical layer of the backlight device. Furthermore, the fluorescent member emits visible light when excited by ambient light. For this reason, according to the liquid crystal display device of the present invention, visual recognition from the outside of the imaging unit is suppressed, and a high-quality display image can be obtained.

  In the present invention, the “space between the backlight device and the liquid crystal display panel” refers to a space provided for securing an optical imaging distance of the imaging unit (focal length of the imaging optical system), The size and shape are not particularly limited.

  In the liquid crystal display device according to the present invention, it is preferable that the fluorescent member includes a phosphor that emits the visible light when excited by light having a wavelength in the ultraviolet region. In this case, visual recognition from the outside of the imaging unit is further suppressed. In addition, as the fluorescent member, it is possible to use a fluorescent member further provided with a light-transmitting substrate, and a phosphor layer formed of the phosphor is provided on the main surface of the substrate.

  In the liquid crystal display device according to the present invention, the detection light source unit emits light having a wavelength of 700 nm or more as the detection light, the imaging unit receives only light having a wavelength of 700 nm or more, and the fluorescence light is emitted. The member is preferably configured to transmit light having a wavelength of 700 nm or more. In particular, the detection light source unit emits light with a wavelength of 800 nm or more and 1000 nm or less as the detection light, the imaging unit receives only light with a wavelength of 800 nm or more, and the fluorescent member has a wavelength of 800 nm or more. It is preferable that the light is transmitted. According to these aspects, it is possible to reliably suppress the imaging unit from being visually recognized from the outside, and it is possible to obtain a high-quality captured image.

  Furthermore, in the liquid crystal display device according to the present invention, it is preferable that an excitation light source unit that irradiates excitation light to the fluorescent member provided in the optical layer is provided in the space. According to this aspect, it is possible to further suppress the imaging unit from being visually recognized from the outside.

  The liquid crystal display device according to the present invention further includes a reflecting member formed to reflect a part of incident light and transmit the other part, and the reflecting member includes the liquid crystal display panel and the back. Between the light device, with the reflection surface facing the space, the light device is disposed so as to surround the space, the excitation light source unit is disposed on the back side of the reflection member, and the reflection member is interposed through the reflection member. It is also preferable that the fluorescent member is irradiated with excitation light. According to this aspect, it is possible to suppress the display area from becoming dark due to the presence of a space between the backlight device and the liquid crystal display panel. At the same time, it is possible to reliably prevent the imaging unit from being visually recognized from the outside.

  Furthermore, in the liquid crystal display device according to the present invention, an area of a light emitting region of the backlight device is set larger than an area of a display region of the liquid crystal display panel, and the liquid crystal display panel is observed on the liquid crystal display panel. A light-shielding part that shields light that enters from the person side or the back surface side and passes through the liquid crystal display panel through a region other than the display region, and the imaging unit shields the light in the thickness direction of the liquid crystal display panel. It is also preferable to adopt an aspect in which they are arranged so as to overlap with the parts. According to this aspect, the effect of suppressing the visual recognition of the imaging unit can be further enhanced.

  In the liquid crystal display device according to the present invention, the liquid crystal display panel includes a filter substrate, a liquid crystal layer, and an active matrix substrate having a plurality of TFT elements, and each of the plurality of TFTs is provided in a lowermost layer. It is preferable to provide a metal film. Further, the liquid crystal display panel includes a filter substrate, a liquid crystal layer, and an active matrix substrate, and a surface of the active matrix substrate that is not in contact with the liquid layer is subjected to a reflection enhancement process. preferable. As described above, since the light emitted from the backlight device can be efficiently reflected toward the fluorescent member, it is effective when the light included in the light emitted from the backlight device is used as excitation light. The effect of suppressing the visual recognition can be enhanced.

(Embodiment 1)
Hereinafter, the liquid crystal display device according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing an overall schematic configuration of the liquid crystal display device according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view showing the positional relationship of the main parts of the liquid crystal display device shown in FIG.

  3 is a diagram showing a schematic configuration of the detection light source unit shown in FIGS. 1 and 2, FIG. 3A is a cross-sectional view cut along the emission direction of detection light, and FIG. 3B is a front view. FIG. FIG. 4 is a cross-sectional view illustrating a schematic configuration of the imaging unit illustrated in FIGS. 1 and 2. FIG. 5 is a cross-sectional view illustrating a schematic configuration of the fluorescent member illustrated in FIGS. 1 and 2.

  As shown in FIGS. 1 and 2, the liquid crystal display device according to the first embodiment has a liquid crystal display panel 2, an imaging unit 4 having an imaging optical system, a detection light source unit 9, and the liquid crystal display panel 2 on the back surface. And a backlight device 5 that illuminates from the side. The detection light source unit 9 emits detection light to the viewer side of the liquid crystal display panel. The imaging unit 4 captures an image of the observer side of the liquid crystal display panel 2.

  As shown in FIG. 3, in the first embodiment, the detection light source unit 9 includes a plurality of light sources 14 that emit detection light. Each light source 14 is arrange | positioned in parallel so that each output direction may correspond. Each light source 14 is a light emitting diode that emits light having a wavelength in the infrared region. Reference numeral 22 denotes a frame of the detection light source unit 9, and reference numeral 23 denotes a resin fixing member that fixes each light source 14 to the frame 22. Reference numeral 24 denotes a light guide formed of a transparent resin material.

  As shown in FIG. 2, in the first embodiment, a plurality of detection light source units 9 are arranged around the display area 3 on the viewer side of the liquid crystal display panel 2. Specifically, four detection light source units 9 are arranged, and each detection light source unit 9 is arranged so as to surround the display region 3 along any side of the display region 3. However, the number of the detection light source units 9 is not particularly limited. For example, the number of the detection light source units 9 may be two, and the detection light source units 9 may be arranged only on two opposite sides. In addition, the detection light source unit 9 can be arranged on the back side of the liquid crystal display panel 2 with the detection light emission direction directed toward the observer side. As shown, it is preferably arranged on the viewer side of the liquid crystal display panel 2.

  As shown in FIGS. 1 and 2, the backlight device 5 includes a plurality of fluorescent lamps 6 serving as a light source, and an optical layer 7 disposed on the liquid crystal display panel 2 side of the fluorescent lamp 6. The imaging unit 4 is disposed inside the backlight device 5.

  In the first embodiment, the backlight device 5 is a direct type backlight device. In the backlight device 5, a plurality of fluorescent lamps 6 are arranged in a bathtub type housing 8 in a state parallel to each other (see FIG. 2). A reflective sheet is attached to the inner surface of the housing 8. The optical layer 7 is formed by, for example, sequentially laminating a diffusion plate, a diffusion sheet, a prism sheet, a reflection / polarization sheet, and the like. Furthermore, the imaging unit 4 is disposed on the bottom surface of the housing 8 so as to be sandwiched between the adjacent fluorescent lamps 8.

  As shown in FIG. 4, in the first embodiment, the imaging unit 4 includes a lens element 30 that forms an imaging optical system, and a solid-state imaging element 32 that receives an image formed by the lens element 30. And. The solid-state imaging device 32 is a solid-state imaging device such as a CCD solid-state imaging device or a MOS solid-state imaging device. The lens element 30 and the solid-state image sensor 32 are held by the frame 33 so that the optical axis 30a of the lens element 30 and the normal line 32a passing through the center of the light-receiving surface of the solid-state image sensor 32 coincide.

  In addition, since the wavelength of the detection light is set in the infrared region, when visible light reflected by the subject 1 enters the imaging unit 4, the visible light becomes a noise component. Examples of visible light here include illumination light emitted from a backlight and passing through the liquid crystal display panel 2, and light from the outside of the liquid crystal display device. Therefore, as shown in FIG. 4, an optical filter 31 that transmits only light having a wavelength in the infrared region is attached to the incident surface side of the lens element 30. Therefore, the imaging unit 4 can receive only the detection light emitted from the detection light source unit 9.

  Further, as shown in FIGS. 1 and 2, the backlight device 5 is arranged so that a space 25 exists between the backlight device 5 and the liquid crystal display panel 2. The focal length of the imaging optical system is ensured. In the first embodiment, the liquid crystal display panel 2 and the backlight device 5 are held by a frame 21 at a certain distance. For example, if the size of the liquid crystal display panel 2 is about 30 inches, the distance between the liquid crystal display panel 2 and the backlight device 5 is set to about 15 cm. A transparent resin material may be filled between the liquid crystal display panel 2 and the backlight device 5 in order to increase the strength of the liquid crystal display device.

  In the first embodiment, it is preferable to provide a plurality of imaging units 4 as shown in FIGS. 1 and 2. In this case, each of the plurality of imaging units 4 is arranged so as to be able to image the state on the viewer side in different areas in the display area 3. As a result, compared with the case where only a single imaging unit is provided, the imaging area of each imaging unit 4 can be narrowed, and the optical imaging distance required by the imaging unit 4 can be shortened. Therefore, compared with the case where only a single imaging unit is provided, the distance between the liquid crystal display panel 2 and the backlight device 5 can be shortened, and the liquid crystal display device can be thinned.

  With such a configuration, in Embodiment 1, the detection light emitted from the detection light source unit 9 is reflected by the subject 1 existing on or near the display area. Further, the reflected detection light is incident on the liquid crystal display panel 2 from the observer side of the liquid crystal display panel 2 and passes through the liquid crystal display panel 2 and the imaging optical system (see FIG. 4). The imaging unit 4 receives the detection light that has passed through the liquid crystal display panel 2 and the imaging optical system, and thereby images the state of the liquid crystal display panel 2 on the observer side.

  Therefore, according to the liquid crystal display device in the first embodiment, the heat generation amount can be reduced, the noise can be reduced, and the size can be reduced. Further, since the imaging unit 4 includes the imaging optical system, the conventional input function is provided. Compared to a display device, it is possible to capture a high-resolution image.

  In the first embodiment, as shown in FIGS. 1 and 2, the backlight device 5 is preferably configured such that the area of the light emitting region is larger than the area of the display region 3. This is because the irradiation area of the liquid crystal display panel 2 tends to decrease when the liquid crystal display panel 2 and the backlight device 5 are separated from each other.

  Furthermore, if the space 25 is provided between the liquid crystal display panel 2 and the backlight device 5 as described above, the illumination light may not easily reach the area near the outer edge of the display area 3 of the liquid crystal display panel 2. There is. In this case, the brightness of the area near the outer edge of the display area 3 is lowered, and the display quality of the liquid crystal display device may be lowered.

  Therefore, in the first embodiment, as shown in FIGS. 1 and 2, the side mirror 13 is arranged in the space 25. The side mirror 13 is a total reflection mirror, and is disposed so as to surround the space 25 with the reflection surface facing the space 25. Illumination light traveling toward the side wall of the frame 21 is reflected to the display region 3 by the side mirror 13, and thus the above-described deterioration in display quality can be avoided.

  In the first embodiment, the liquid crystal display panel 2 includes an active matrix substrate 2c, a liquid crystal layer 2b, and a filter substrate (counter substrate) 2a. The liquid crystal layer 2b is sandwiched between the active matrix substrate 2c and the filter substrate 2a. Illustration of a seal for sealing the liquid crystal layer 2b is omitted. In addition, a polarizing plate (not shown) is provided on the surface opposite to the liquid crystal layer 2b side in each of the filter substrate 2a and the active matrix substrate 2c.

  Furthermore, although not shown, a plurality of active elements (TFT elements) arranged in a matrix are formed on the active matrix substrate 2c. The active element constitutes a pixel, and a region overlapping with the region where the pixel is provided in the thickness direction (indicated by a thick line arrow in FIG. 1) is a display region 3. Further, although not shown, the active matrix substrate 2c is provided with a drive circuit such as a gate drive circuit and a source drive circuit. A plurality of color filters (not shown) corresponding to each pixel and counter electrodes are formed on the filter substrate 2a.

  Incidentally, as described above, the imaging unit 4 is disposed inside the backlight device 5. Therefore, in the first embodiment, the optical path of the detection light received by the imaging unit 4 in the optical layer 7 is determined so as to prevent the optical layer 7 from preventing the detection light from entering the imaging unit 4. An opening 7a is provided in the overlapping region.

  However, when the imaging unit 4 is exposed to the outside through the opening 7a, the liquid crystal display panel 2 has transparency, so that the imaging unit 4 is visually recognized from the observer side, and the quality of the display image is impaired. End up. Therefore, as shown in FIGS. 1 and 2, a fluorescent member 12 that transmits detection light and emits visible light by excitation with ambient light is installed in the opening 7 a of the optical layer 7.

  Specifically, in the first embodiment, as shown in FIG. 5, the fluorescent member 12 includes a light-transmitting substrate 12b formed of resin or glass, and a fluorescent light provided on the main surface of the substrate 12b. And a body layer 12a. The phosphor layer 12a is formed of a phosphor that emits visible light when excited by light (ultraviolet rays) having a wavelength in the ultraviolet region (for example, 320 nm to 400 nm). As a result, according to the first embodiment, visual recognition from the outside of the imaging unit 4 is suppressed by the visible light emitted from the fluorescent member 12.

  Moreover, in this Embodiment 1, in order to perform visible light emission efficiently, the excitation light source part 10 is provided as shown in FIG.1 and FIG.2. The excitation light source unit 10 is disposed in a space 25 between the liquid crystal display panel 2 and the backlight device 5, and irradiates the fluorescent member 12 provided on the optical layer 7 of the backlight device 5 with excitation light.

  The excitation light source unit 10 is configured in the same manner as the detection light source unit 9. However, since the phosphor is excited by ultraviolet rays, the excitation light source unit 10 includes a light emitting diode that emits ultraviolet rays as the light source 15, unlike the detection light source unit 9. Further, the excitation light source unit 10 is arranged so that the direction in which the intensity of the ultraviolet light emitted therefrom is highest faces the fluorescent member 12. Thus, in this Embodiment 1, since the fluorescence member 12 emits visible light reliably by the irradiation of the ultraviolet light by the excitation light source part 10, the visual recognition from the outside of the imaging part 4 is suppressed reliably.

  In the first embodiment, the light source 15 of the excitation light source unit 10 is not limited to a light emitting diode that emits only ultraviolet rays. The light source 15 may be a light emitting diode that emits light including ultraviolet light, and may emit visible light or infrared light together with ultraviolet light.

  Moreover, in this Embodiment 1, what is excited by visible light can also be used as the fluorescent substance which forms the fluorescent substance layer 12a. However, when a phosphor excited by visible light such as blue light or red light is used, the visible light may be visually recognized by an observer. Therefore, in this case, it is preferable to use a phosphor that is excited by white light. When a phosphor that is excited by visible light is used, a light emitting diode that emits visible light, particularly white light, is used as the light source 15 of the excitation light source unit 10.

  As shown in FIGS. 1 and 2, in the first embodiment, the liquid crystal display panel 2 includes a light shielding portion 11. The light shielding unit 11 is incident from the observer side or the back surface side of the liquid crystal display panel 2 and shields light passing through the liquid crystal display panel 2 through a region other than the display region 3. Specifically, the light shielding portion 11 is a non-transparent frame-shaped plate material, and the opening thereof is formed in accordance with the shape of the display region 3. The light shielding unit 11 is disposed on the display surface of the liquid crystal display panel 2.

  Further, the excitation light source unit 10 is arranged so as not to overlap the display region 3 in the thickness direction of the liquid crystal display panel 2, that is, to overlap the light shielding unit 11 in the thickness direction of the liquid crystal display panel 2. Therefore, the excitation light source unit 10 is not visually recognized by the light shielding unit 11 from the outside.

  In the first embodiment, the wavelength of the detection light may be in the infrared region, but is set to 700 nm or more, preferably 800 nm or more, and particularly preferably 850 nm or more. This is because, if it is set in such a range, the transmittance of the detection light with respect to the color filters and polarizing plates constituting the liquid crystal display panel 2 can be increased. In general, since a solid-state imaging device capable of receiving light having a wavelength exceeding 1000 nm is expensive, the upper limit of the wavelength of detection light is preferably set to 1000 nm or less.

  Further, when the wavelength of the detection light is set in the above range, the optical filter 31 shown in FIG. 4 is a high pass that transmits only light having a wavelength of 700 nm or more, preferably 800 nm or more, and particularly preferably 850 nm or more. It is better to use a filter. In this case, the fluorescent member 12 preferably transmits light having a wavelength of 700 nm or more, preferably 800 nm or more, particularly preferably 850 nm or more.

(Embodiment 2)
Next, a liquid crystal display device according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing an overall schematic configuration of the liquid crystal display device according to Embodiment 2 of the present invention.

  As shown in FIG. 6, the liquid crystal display device according to the second embodiment has a liquid crystal display according to the first embodiment shown in FIGS. 1 and 2 in the configuration of the excitation light source unit 16 that irradiates the fluorescent member 12 with excitation light. Different from the device. In other respects, the liquid crystal display device according to the second embodiment is the same as the liquid crystal display device according to the first embodiment. Also in the second embodiment, the fluorescent member 12 is excited by ultraviolet rays and emits visible light. To emit. Hereinafter, differences will be described.

  As shown in FIG. 6, in the second embodiment, the excitation light source unit 16 is a backlight device, and like the backlight device 5, a plurality of fluorescent lamps 17 serving as a light source, an optical layer 18, And a bathtub-shaped casing 19. With this configuration, the excitation light source unit 16 can emit light having the same spectral distribution as the light emitted from the backlight device 5.

  In general, the light emitted from the fluorescent lamp contains ultraviolet rays. Therefore, also in the second embodiment, the excitation light source unit 16 can emit ultraviolet rays toward the fluorescent member 12 in the same manner as the excitation light source unit 10 shown in FIG. 1 in the first embodiment. In the second embodiment, the phosphor constituting the fluorescent member 12 is excited by ultraviolet rays contained in the light emitted from the fluorescent lamp 17. In the second embodiment, it is preferable to use a fluorescent lamp 17 that is not provided with a member that cuts ultraviolet rays such as an ultraviolet absorbing film. Further, as the fluorescent lamp 17, a fluorescent lamp that is made of ultraviolet transmissive glass and can emit a large amount of ultraviolet rays can be used.

  Further, the excitation light source unit 16 is disposed on the back side of the side mirror 13 in a state where the upper surface of the optical layer 18 serving as an emission surface is superimposed on the side mirror 13. In the second embodiment, the side mirror 13 is a translucent mirror that transmits a part of incident light and reflects the other part. Therefore, the light emitted from the excitation light source unit 16 is the side mirror 13. To reach the fluorescent member 12.

  As described above, according to the second embodiment, the space 25 is illuminated by the light emitted from the excitation light source unit 16 in addition to the reflected light of the side mirror 13. For this reason, it is possible to further suppress the deterioration in display quality due to the decrease in luminance in the area near the outer edge of the display area 3.

  Further, in the second embodiment, the excitation light source unit 16 is located behind the side mirror 13 as viewed from the observer. For this reason, the excitation light source part 16 is not visually recognized by an observer. Therefore, the size and number of the excitation light source units 16 can be set as appropriate, and the degree of freedom in designing the excitation light source unit 16 is higher than that in the first embodiment.

  Also in the second embodiment, as in the first embodiment, a phosphor that is excited by visible light can be used as the phosphor forming the phosphor layer. In particular, in the second embodiment, the excitation light source unit 16 is configured in the same manner as the backlight device 5, and the emitted light includes white light, so that it is excited by white light. It is preferable to use a phosphor.

(Embodiment 3)
Next, a liquid crystal display device according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view showing an overall schematic configuration of the liquid crystal display device according to Embodiment 3 of the present invention. FIG. 8 is a cross-sectional view illustrating a schematic configuration of an imaging unit provided in the liquid crystal display device illustrated in FIG. 7.

  As shown in FIG. 7, the liquid crystal display device in the third embodiment is different from the liquid crystal display devices in the first and second embodiments in the arrangement of the imaging unit 20 and the configuration of the excitation light source unit. In other respects, the liquid crystal display device according to the third embodiment is configured in the same manner as the liquid crystal display devices according to the first and second embodiments. Hereinafter, differences will be described.

  In the third embodiment, the imaging unit 20 is arranged so as not to overlap the display region 3 in the thickness direction of the liquid crystal display panel 2, that is, to overlap the light shielding unit 11. For this reason, according to this Embodiment 3, compared with Embodiment 1 and 2, it can suppress that the imaging part 20 is visually recognized from the exterior further.

  Further, the third embodiment includes the excitation light source unit 10 shown in FIG. 1 and the excitation light source unit 16 shown in FIG. 6, and both irradiate the fluorescent member 12 with ultraviolet rays. Therefore, this also makes it difficult for the imaging unit 20 to be visually recognized from the outside as compared with the first and second embodiments.

  In the third embodiment, as shown in FIG. 7, the imaging unit 20 is arranged near the outer edge of the light emitting area of the backlight device. Therefore, the imaging unit 20 has the configuration shown in FIG. 8. Things are used. As shown in FIG. 8, the imaging unit 20 also includes a solid-state imaging device 32, a lens element 34, and an optical filter 31, similar to the example shown in the example of FIG. 4. Among these, the solid-state imaging device 32 and the optical filter 31 are the same as those shown in the example of FIG.

  However, in the imaging unit 20, unlike the example illustrated in FIG. 4, the lens element 34 and the solid-state imaging element 32 constitute a so-called shift optical system. Specifically, in the solid-state imaging element 32 and the lens element 34, the normal line 32a passing through the center of the light receiving surface of the solid-state imaging element 32 and the optical axis 34a of the lens element 34 are parallel, and the optical axis 34a is the normal line. The frame 35 is held in a state shifted from 32a.

  By the way, if the imaging unit 20 does not include the shift optical system and is configured in the same manner as the imaging unit 4 illustrated in FIG. 4, the display region is imaged from near the outer edge of the light emitting region of the backlight device 5. In other words, the imaging unit 20 needs to tilt the optical axis 34 a of the lens element 34 toward the display region 3. In this case, since an image with trapezoidal distortion is formed on the light receiving surface of the image sensor 32, it is necessary to perform image processing thereafter. On the other hand, in the third embodiment, since the imaging unit 20 includes the shift optical system as described above, even when the display region is imaged near the outer edge of the light emitting region, the imaging unit 20 The display area 3 can be imaged without tilting. Therefore, an image with little trapezoidal distortion is formed on the light receiving surface of the image sensor 32.

  When such a shift optical system is adopted, it is necessary to transmit the lens element 34 without oblique light being kicked. Therefore, in the third embodiment, the diameter of the lens element 34 is larger than that of the lens element 30 shown in FIG.

  The “imaging optical system” as used in the present invention is a lens that has a focal point near the surface of the liquid crystal display panel and the light receiving surface of the imaging unit, and forms an image near the surface of the liquid crystal display panel on the light receiving surface. Refers to the system. In the example of FIGS. 4 and 7, the imaging optical system is configured by only lens elements, but may be configured by a lens group including a plurality of lens elements.

  In the third embodiment, as in the first and second embodiments, as the phosphor forming the phosphor layer, a phosphor other than one excited by ultraviolet rays, for example, one excited by visible light is used. You can also. Further, since white light is included in the light emitted from the excitation light source unit 16, it is preferable to use a phosphor that is excited by white light.

  The liquid crystal display device in the present invention is not limited to the liquid crystal display device described in the first to third embodiments. For example, in Embodiments 1 to 3, the excitation light source unit is provided, but the present invention is not limited to these modes. The liquid crystal display device according to the present invention may be in a mode that does not include an excitation light source unit that irradiates the fluorescent member with excitation light.

  Even in this case, the phosphor forming the phosphor layer 12a can be excited by the light incident on the inside of the liquid crystal display device from the outside or the light emitted from the backlight 5. Therefore, the visual recognition from the outside of the imaging unit is suppressed by the visible light emitted from the fluorescent member 12. However, in this aspect, as shown in FIG. 7 in Embodiment 3, it is preferable that the imaging unit is arranged so as to overlap the light shielding unit in the thickness direction of the liquid crystal display panel.

  Further, when the light included in the light emitted from the backlight device 5 is used as the excitation light in a mode in which the excitation light source unit is not provided, for example, the active matrix substrate 2c (see FIGS. 1, 6, and 7). It is preferable to form a metal film on the lowermost layer of a plurality of TFTs provided on the substrate. Specifically, it is preferable to form a metal gate electrode and gate wiring in the lowermost layer. In this way, since the emitted light from the backlight device 5 can be efficiently reflected by the lowermost metal film, the fluorescent member 12 can be reliably excited by the excitation light contained in the reflected light.

  Further, in the embodiment in which the excitation light source unit is not provided, and the light included in the light emitted from the backlight device 5 is used as the excitation light, the back surface of the active matrix substrate (the surface on the side not in contact with the liquid layer 2b) ) Is preferably subjected to an increased reflection treatment. The increased reflection treatment can be performed by using, for example, a thin film multilayer deposition technique. When the thin film multilayer deposition technique is used, the reflectance can be freely increased. However, if the reflectance is excessively increased, the brightness of the display region 3 is lowered. Therefore, the reflectance is preferably set according to the application or specification of the liquid crystal display device.

  Further, in a general liquid crystal display device, an AR (Anti Reflection) process (interface reflection prevention process) is performed on the back surface of the active matrix substrate in order to prevent reflection of illumination light from the backlight device. However, when the excitation light source unit is not provided and the light included in the light emitted from the backlight device 5 is used as the excitation light, it is preferable not to perform the AR process. This is because the emitted light from the backlight device is efficiently guided to the fluorescent member 12, and the fluorescent member 12 is reliably excited by the excitation light included in the light reflected by the back surface of the active matrix substrate.

  As described above, the liquid crystal display device of the present invention has an input function, is useful as a display device for personal computers, televisions, game machines, and the like, and has industrial applicability.

FIG. 1 is a cross-sectional view showing an overall schematic configuration of the liquid crystal display device according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view showing the positional relationship of the main parts of the liquid crystal display device shown in FIG. 3 is a diagram showing a schematic configuration of the detection light source unit shown in FIGS. 1 and 2, FIG. 3A is a cross-sectional view cut along the emission direction of detection light, and FIG. 3B is a front view. FIG. FIG. 4 is a cross-sectional view illustrating a schematic configuration of the imaging unit illustrated in FIGS. 1 and 2. FIG. 5 is a cross-sectional view illustrating a schematic configuration of the fluorescent member illustrated in FIGS. 1 and 2. FIG. 6 is a cross-sectional view showing an overall schematic configuration of the liquid crystal display device according to Embodiment 2 of the present invention. FIG. 7 is a cross-sectional view showing an overall schematic configuration of the liquid crystal display device according to Embodiment 3 of the present invention. FIG. 8 is a cross-sectional view illustrating a schematic configuration of an imaging unit provided in the liquid crystal display device illustrated in FIG. 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Subject 2 Display panel 2a Filter substrate 2b Liquid crystal layer 2c Active matrix substrate 3 Display area 4, 20 Imaging unit 5 Backlight device 6 Fluorescent lamp 7 Optical layer 7a Opening provided in optical layer 8 Housing 9 Detection light source unit 10, DESCRIPTION OF SYMBOLS 16 Excitation light source part 11 Light-shielding part 12 Fluorescent member 13 Side mirror 14 Light source of detection light source part 15 Light source (light emitting diode) of excitation light source part
17 Light source of excitation light source (fluorescent lamp)
DESCRIPTION OF SYMBOLS 18 Optical layer of excitation light source part 19 Case of excitation light source part 21 Frame of display device 22 Frame of detection light source part 23 Fixing member 24 Light guide 25 Space between liquid crystal display panel and backlight device 30, 34 Lens element ( Imaging optics)
30a, 34a Optical axis of lens element 31 Optical filter 32 Solid-state imaging device 32a Normal line passing through center of light-receiving surface of solid-state imaging device 33, 35 Frame of imaging unit

Claims (10)

A liquid crystal display panel, an imaging unit having an imaging optical system, a detection light source unit that emits detection light having a wavelength in the infrared region to the viewer side of the liquid crystal display panel, and the liquid crystal display panel from the back side A backlight device for illuminating,
The backlight device includes a light source and an optical layer disposed on the liquid crystal display panel side of the light source, and is disposed so that there is a space between the liquid crystal display panel,
The imaging unit is disposed inside the backlight device, and receives the detection light incident on the liquid crystal display panel from an observer side and passing through the liquid crystal display panel and the imaging optical system. By imaging the state of the liquid crystal display panel on the viewer side,
In a region overlapping the optical path of the detection light received by the imaging unit in the optical layer of the backlight device, a fluorescent member is provided,
The liquid crystal display device, wherein the fluorescent member transmits the detection light and emits visible light by excitation.   The liquid crystal display device according to claim 1, wherein the fluorescent member includes a phosphor that emits the visible light when excited by light having a wavelength in an ultraviolet region.   The liquid crystal display device according to claim 2, wherein the fluorescent member further includes a light-transmitting substrate, and a phosphor layer formed of the phosphor is provided on a main surface of the substrate. The detection light source unit emits light having a wavelength of 700 nm or more as the detection light,
The imaging unit receives only light having a wavelength of 700 nm or more,
The display device according to claim 1, wherein the fluorescent member transmits light having a wavelength of 700 nm or more. The detection light source unit emits light having a wavelength of 800 nm to 1000 nm as the detection light,
The imaging unit receives only light having a wavelength of 800 nm or more,
The display device according to claim 4, wherein the fluorescent member transmits light having a wavelength of 800 nm or more.   The liquid crystal display device according to claim 1, wherein an excitation light source unit that irradiates excitation light to the fluorescent member provided in the optical layer is provided in the space. A reflection member formed to reflect part of the incident light and transmit the other part;
The reflecting member is disposed between the liquid crystal display panel and the backlight device so as to surround the space in a state where the reflecting surface faces the space.
The liquid crystal display device according to claim 6, wherein the excitation light source unit is disposed on a back side of the reflecting member and irradiates the fluorescent member with excitation light through the reflecting member. The area of the light emitting region of the backlight device is set larger than the area of the display region of the liquid crystal display panel,
The liquid crystal display panel includes a light-shielding portion that is incident from an observer side or a back surface side of the liquid crystal display panel and shields light passing through the liquid crystal display panel through a region other than the display region,
The liquid crystal display device according to claim 1, wherein the imaging unit is disposed so as to overlap the light shielding unit in a thickness direction of the liquid crystal display panel. The liquid crystal display panel includes a filter substrate, a liquid crystal layer, and an active matrix substrate having a plurality of TFT elements,
The liquid crystal display device according to claim 1, wherein each of the plurality of TFTs includes a metal film in a lowermost layer.   The liquid crystal display panel includes a filter substrate, a liquid crystal layer, and an active matrix substrate, and a surface of the active matrix substrate that is not in contact with the liquid layer is subjected to a reflection enhancement process. The liquid crystal display device according to any one of 5.

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