JP2007156647A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device which is less in heat generation, noise and, and is capable of capturing an image with high resolution. <P>SOLUTION: This display device is provided with: a display panel 2 having light permeability; an image pickup part 4 having an image formation optical system; and a detection light source part 7 having a light source 15 for emitting detection rays of light to the observer side of the display panel 2. The detection light source part 7 is arranged in the peripheral region of a display region 3 of the display panel 2. Also, the detection light source part 7 is provided with light shielding members 16 and 17 for limiting divergence in the thickness direction of the display panel 2 of the detection rays of light. The detection rays of light made incident from the observer side to the display panel 2, and passing through the display panel 2 and the image formation optical system are received by the image pickup part 4, and a status at the observer side of the display panel 2 is imaged. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device, and more particularly to a 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 with the 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 liquid crystal 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 liquid crystal display device disclosed in Patent Document 2 has a configuration that enables capturing of an image, but does not include an imaging optical system. It is impossible to obtain a captured image. The liquid crystal display device of Patent Document 2 has a problem that it is impossible to capture a high resolution.

  An object of the present invention is to provide a display device that solves the above-described 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 display device according to the present invention includes a display panel having optical transparency, an imaging unit having an imaging optical system, and a detection having a light source that emits detection light to an observer side of the display panel. A light source unit, and the detection light source unit is disposed around a display area on the viewer side of the display panel, and includes a limiting member that limits a divergence degree of the detection light in the thickness direction of the display panel. The imaging unit receives the detection light incident on the display panel from the observer side and passes through the display panel and the imaging optical system, and images the state of the display panel on the observer side. It is characterized by doing.

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

A display device according to the present invention includes a display panel having optical transparency, an imaging unit having an imaging optical system, and a detection light source unit having a light source that emits detection light to an observer side of the display panel, The detection light source unit is disposed around a display area on the viewer side of the display panel, and includes a limiting member that limits a divergence degree of the detection light in the thickness direction of the display panel. The detection light incident on the display panel from the viewer side and passing through the display panel and the imaging optical system is received, and the state of the display panel on the viewer side is imaged.

  With the above features, the 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. In the display device according to the present invention, the divergence of the detection light emitted from the detection light source unit is limited. For this reason, it is possible to suppress even an object located at a position away from the display area of the display panel, and it is possible to image only a subject near the display area. In addition, it is possible to improve the sensing accuracy, and it is possible to suppress a reduction in imaging quality due to detection light directly entering the imaging unit.

  The display device according to the present invention includes, on the viewer side of the display panel, a transparent plate that covers the display area of the display panel, and the transparent plate is disposed so that a space is formed between the display area and the display area. Preferably, the detection light source unit has a mode (first mode) arranged in the space so that the detection light is emitted from the space to the viewer side of the transparent plate. . According to the first aspect, since the detection light can be efficiently applied to the portion of the object to be imaged on the display area side, the use efficiency of the detection light can be improved. As a result, the sensitivity of the imaging unit is improved. be able to.

  In the first aspect, a distance from a point on the periphery of the display area closest to the light source to a point on the other edge opposite to the point is a, and the detection light is the periphery of the display area. An upper limit of the height from the main surface on the observer side of the transparent plate that can be reached on the observer side, b, including the center of the light emitting surface of the light source and parallel to the display area; The distance between the transparent plate and the main surface on the observer side is c, passes through the center of the light emitting surface of the light source and is perpendicular to the display region, and on the periphery of the display region closest to the light source. From the main surface on the observer side of the transparent plate, where d is a distance from a line that passes through a point and is perpendicular to the display area, and the detection light reaches the observer side at the periphery of the display area When the maximum height is z, the degree of divergence is limited by the limiting member. Said exit angle in the thickness direction of the display panel of the detection light γ is represented by the following formula (1) and the following formula (2) is good is set so as to satisfy. In this case, the certainty of the various effects described above can be increased.

(Equation 3)
(A / 2) tan (γ / 2) <z <b (1)

(Equation 4)
z = (a + d) tan (γ / 2) −c (2)

  In the display device according to the present invention, it is also preferable that the limiting member is an aspect (second aspect) in which the limiting member is a light shielding member disposed on at least one of the display area side and the opposite side of the light source. According to the second aspect, the divergence of the detection light can be limited with a simple configuration.

  In the second aspect, the light shielding member serving as the limiting member is disposed on the display area side and the opposite side of the light source, and the light source has a direction in which the luminance of the emitted detection light is highest, You may arrange | position so that it may become a direction parallel to the said display area. In the second aspect, the light blocking member serving as the limiting member is disposed on the display region side of the light source, and the light source has a direction in which the luminance of the emitted detection light is highest in the display. You may arrange | position so that it may become the direction which gets away from the said display area | region gradually on the back side of an area | region. Furthermore, in the second aspect, the light shielding member serving as the limiting member is disposed on the opposite side of the light source from the display region side, and the light source has a direction in which the luminance of the emitted detection light is highest. The observer may be arranged so as to gradually move away from the display area.

  Further, in the display device according to the present invention, the limiting member is a lens element, and the lens element is arranged so that an optical axis thereof coincides with a direction with the highest luminance of the emitted detection light. It is also preferable to adopt a mode (third mode). According to the said 3rd aspect, the utilization efficiency of a detection light can be improved further.

  In the display device according to the present invention, it is preferable that the light source is a light emitting diode that emits light having a wavelength of 700 nm or more, and the imaging unit receives only light having a wavelength of 700 nm or more. Preferably, the light source emits light having a wavelength of 800 nm or more and 1000 nm or less, and the imaging unit receives only light having a wavelength of 800 nm or more. In this case, noise due to visible light can be removed, and the resolution of the captured image can be further increased.

  In the display device according to the present invention, the display panel may be a liquid crystal display panel or an EL display panel.

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

  As shown in FIGS. 1 and 2, the display device according to the present embodiment includes a display panel 2 having optical transparency, an imaging unit 4 having an imaging optical system, and a detection light source unit 7. The detection light source unit 7 includes a light source 15 that emits detection light to the viewer side of the display panel 2. The detection light source unit 7 is arranged around the display region 3 on the viewer side of the display panel 2.

  In the present embodiment, the light source 15 is a light emitting diode. The wavelength of the detection light emitted from the light source 15 is preferably set in a region other than the visible region. The wavelength of the detection light will be described later. Moreover, each detection light source part 7 radiate | emits detection light toward the detection light source part 7 in the position facing it.

  In the present embodiment, four detection light source units 7 are arranged. Each detection light source part 7 is arrange | positioned so that the display area 3 may be enclosed along any edge | side of the display area 3 (refer FIG. 2). However, the number of the detection light source parts 7 is not specifically limited. For example, the number of the detection light source units 7 may be two, and the detection light source units 7 may be arranged only on two opposite sides.

  As shown in FIGS. 1 and 2, the imaging unit 4 detects light that enters the display panel 2 from the observer side and passes through the display panel 2 and the imaging optical system (see FIG. 4 described later). Is received, and the state of the display panel 2 on the viewer side is imaged. Specifically, the imaging unit 4 receives detection light emitted from the detection light source unit 7 and then reflected by the subject 1 and incident on the display panel 2 via the imaging optical system (see FIG. 3). Thus, the subject 1 is imaged.

  With such a configuration, according to the display device in the present embodiment, the amount of heat generation can be reduced, the noise can be reduced, and the size can be reduced. Moreover, since the imaging unit 4 includes the imaging optical system, the conventional input function can be achieved. Compared with a display device provided with the above, it is possible to capture a high-resolution image.

  In the present embodiment, the transparent plate 14 is disposed on the viewer side of the display panel 2, and the display area 3 of the display panel is covered with the transparent plate 14. The imaging unit 4 mainly captures an object that is in contact with the main surface on the observer side of the transparent plate 14 or an object that is located near the main surface on the observer side of the transparent plate 14 as the subject 1. To do.

  The transparent plate 14 is installed so that a space 22 is formed between it and the display area 3. Further, the detection light source unit 7 is arranged in the space 15 so that the detection light is emitted from the space 15 to the observer side of the transparent plate 14. Therefore, an object that is in contact with the main surface on the observer side of the transparent plate 14 or an object that is located in the vicinity of the main surface on the observer side of the transparent plate 14, that is, a display region of the object to be imaged The detection light is efficiently applied to the side portion. In the present embodiment, the main surface on the observer side of the transparent plate 14 is a sensing surface.

  In addition, the transparent plate 14 should just be a board | plate material formed with transparent materials, such as an acrylic board and a glass plate, for example. The transmittance of the transparent plate 14 does not need to be 100% and may not be less than 100%.

  In the present embodiment, the display panel 2 is a liquid crystal display panel, and the display device is a liquid crystal display device. Further, since the display panel 2 is a liquid crystal display panel, the backlight device 5 is disposed on the back surface of the display panel.

  The 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.

  A plurality of active elements (not shown) arranged in a matrix are formed on the active matrix substrate 2c. The active element constitutes a pixel, and a display region 3 is a region overlapping with a region where the pixel is provided in the thickness direction. 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.

  In addition, the display panel 2 should just be provided with the light transmittance. Other examples of the display panel 2 include an EL display panel. When the display panel 2 is an EL display panel, it is not necessary to arrange a backlight device because the EL display panel emits light. Furthermore, in this case, the display panel 2 is, for example, an ITO (Indium Tin Oxide) film that becomes a transparent electrode (anode), a hole transport layer, an electron transport layer, a back electrode (cathode), etc. in this order on a transparent substrate. It is constructed by stacking.

  The backlight device 5 is a direct-type backlight device and includes a plurality of fluorescent lamps 6 and an optical layer 13. The plurality of fluorescent lamps 6 are disposed 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 13 is formed by sequentially laminating a diffusion plate 9, a diffusion sheet 10, a prism sheet 11, and a reflection / polarization sheet 12.

  In the present embodiment, the display panel 2 and the backlight device 5 have a longer distance than the conventional liquid crystal display device in order to increase the optical imaging distance of the imaging unit 4 (focal length of the imaging optical system). Placed and placed. Specifically, the display panel 2 and the backlight device 5 are held at a certain distance L by the frame 21, and a cavity exists between them. The imaging unit 4 is also held in the frame 21.

  For example, if the size of the display panel 2 is about 30 inches, the distance L between the display panel 2 and the backlight device 5 is set to about 15 cm. A transparent resin material may be filled between the display panel 2 and the backlight device 5 in order to increase the strength of the display device.

  Further, since the distance between the display panel 2 and the backlight device 5 is large, as shown in FIGS. 1 and 2, the backlight device 5 has a light emitting area larger than the display area 3. It is preferable to configure. This is because the irradiation area of the display panel 2 tends to decrease when the distance between the display panel 2 and the backlight device 5 is large.

  Also, as shown in FIGS. 1 and 2, it is preferable to provide a plurality of imaging units 4. In this case, the plurality of imaging units 4 are arranged so as to image different areas. With such a configuration, 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 compared to a case where only a single imaging unit is provided. . Therefore, compared with the case where only a single imaging unit is provided, the distance between the display panel 2 and the backlight device 5 can be shortened, and the display device can be thinned.

  Here, the configuration of the imaging unit 4 will be specifically described with reference to FIG. FIG. 3 is a cross-sectional view illustrating a schematic configuration of an imaging unit provided in the display device illustrated in FIGS. 1 and 2. As shown in FIG. 3, in the present embodiment, the imaging unit 4 includes a lens element 30 that forms an imaging optical system, a solid-state imaging element 32 that receives an image formed by the lens element 30, and a setting. And an optical filter 31 that transmits only light having a wavelength equal to or greater than the wavelength. 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 function of the optical filter 31 will be described later.

  The lens element 30 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 30, the normal line 32a passing through the center of the light receiving surface of the solid-state imaging element 32 and the optical axis 30a of the lens element 30 are parallel, and the optical axis 30a is the normal line. The frame 33 is held in a state shifted from 32a. Further, as shown in FIGS. 1 and 2, in the imaging unit 4, the light receiving surface of the solid-state imaging device 32 is parallel to the display area 3, and the normal line 32 a of the solid-state imaging device 32 is the lens element 30. It arrange | positions so that it may be located in the outer side of the display area 3 rather than the optical axis 30a.

  Thus, in this embodiment, since the shift optical system is employed, an image with little trapezoidal distortion is formed on the light receiving surface of the solid-state imaging device 32. Therefore, according to the present embodiment, an image with excellent image quality can be obtained without performing correction for improving trapezoidal distortion on the imaging data output by the imaging unit 4.

  Note that the configuration of the imaging unit 4 is not limited to the example illustrated in FIG. 3, and the normal line 32 a passing through the center of the light receiving surface of the solid-state imaging element 32 and the optical axis 30 a of the lens element 30 coincide with each other. There may be. However, when the normal line 32a and the optical axis 30a coincide with each other, it is necessary to dispose the imaging unit 4 in a state where they are inclined toward the display area.

  In addition, the “imaging optical system” in the present invention is focused on the vicinity of the surface of the display panel (in this embodiment, the vicinity of the main surface on the observer side of the transparent plate 14) and the light receiving surface of the imaging unit. A lens system that forms an image near the surface of the display panel on the light receiving surface. In the example of FIG. 3, the imaging optical system is configured by only the lens element 30, but may be configured by a lens group including a plurality of lens elements. However, when configuring the shift optical system, the imaging optical system needs to be designed so that the oblique light is not kicked and transmitted through the lens system. In this case, the imaging optical system needs to be configured by a lens system having a large aperture as compared with the case where the shift optical system is not configured.

  Next, the configuration of the detection light source unit 7 will be specifically described with reference to FIGS. 4 and 5. 4 is an enlarged partial cross-sectional view of a part of the cross-sectional view shown in FIG. FIG. 5 is a diagram illustrating a schematic configuration of the detection light source unit illustrated in FIGS. 1 and 2, in which FIG. 5A is a cross-sectional view cut along the emission direction of the detection light, and FIG. FIG.

  In the present embodiment, as shown in FIGS. 5A and 5B, the detection light source unit 7 includes a plurality of light sources 15 arranged in parallel. The emission directions of the light sources 15 are the same. As the light source 15, a light emitting diode is used. Further, the detection light source unit 7 is arranged so that the direction of the highest luminance of the detection light emitted from each light source 15 is parallel to the display region 3. Reference numeral 18 denotes a frame of the detection light source unit 7, and reference numeral 19 denotes a resin fixing member that fixes each light source 15 to the frame 15. Reference numeral 20 denotes a light guide formed of a transparent resin material.

  As shown in FIGS. 4 and 5B, the detection light source unit 7 includes a limiting member that limits the divergence of the detection light in the thickness direction of the display panel 2. In the present embodiment, plate-shaped light shielding members 16 and 17 are used as limiting members. The light shielding member 17 is disposed on the display area 3 side of each light source 15, and the light shielding member 16 is disposed on the opposite side of the display area side of each light source 15, that is, on the transparent plate 14 side. Examples of the light shielding members 16 and 17 include a member that does not transmit detection light, such as a reflection member that reflects detection light, and an absorption member that absorbs detection light. Among these, from the viewpoint of limiting the divergence degree of the light source 15, an absorbing member is preferable.

  Therefore, the emission angle of the detection light emitted from the light source 15 by the light shielding members 16 and 17 in the thickness direction of the display panel 2 is changed from the angle α to the angle γ (α> γ) as shown in FIGS. It will be narrowed. As a result, the height at which the detection light reaches on the periphery of the display area 3 (the height from the main surface on the observer side of the transparent plate 14) is limited. Here, the effect by a limiting member is demonstrated below.

  In order to read the subject 1 existing on the viewer side of the display panel 2, the imaging unit 4 is preferably disposed on the back side of the display panel 2 as shown in FIG. 1. On the other hand, the detection light source unit 7 is preferably arranged on the viewer side of the display panel 2 as shown in FIG. Further, in order to irradiate the entire display area 3 with detection light, it is preferable that the detection light emitted from the light source 15 diverges in the surface direction of the display panel 2.

  In general, however, light diverges in all directions perpendicular to the direction of travel. For this reason, the detection light emitted from the light source 15 diverges not only in the surface direction of the display panel 2 but also in the thickness direction. For this reason, as shown in FIG. 1, the detection light reaches a place away from the display region 3. In addition, since all the subjects existing within the range where the detection light reaches are reflected by the detection light, they are imaged by the imaging unit 4 regardless of the height from the display area 3.

  In this case, the imaging unit 4 cannot obtain information on the height of the subject from the display area 3 (distance in the thickness direction of the display panel), and therefore the subject is in close contact with the sensing surface based on the captured image. It is difficult to determine whether or not Therefore, it may be difficult to use the imaging function of the display device as a touch panel. In addition, as in the embodiment, this means that the transparent plate 14 is disposed on the viewer side of the display region 3 and the main surface of the transparent plate 14 on the viewer side is used in order to increase the use efficiency of the detection light. This is particularly noticeable when the sensing surface is used.

  Further, as shown in FIG. 1, the range in which the detection light reaches is different between the central portion and the peripheral portion of the display region 3. Therefore, depending on the location, there may be a problem that the sensing accuracy is low such that an unnecessary subject is imaged, or conversely, a necessary subject is not imaged. Furthermore, since the detection light emitted from each light source 15 diverges also to the back surface side of the display panel 2, the detection light may be directly incident on the imaging unit 4. In this case, the imaging quality is deteriorated.

  On the other hand, in the present embodiment, as shown in FIGS. 1, 4 and 5B, the thickness of the display panel 2 of the detection light emitted from each light source 15 by the shielding members 16 and 17 is shown. Divergence in direction is limited. For this reason, the range in which the detection light reaches in the thickness direction of the display panel 2 can be reduced, and it can be suppressed that an object located at a position away from the display area 3 of the display panel 2 is imaged. Therefore, according to the present embodiment, the imaging function of the display device can be used as a touch panel. Further, according to the present embodiment, the variation in the range in which the detection light reaches can be reduced, so that the sensing accuracy can be improved. Furthermore, since it is possible to suppress the detection light from directly entering the imaging unit 4, it is possible to suppress deterioration in imaging quality.

  In order to secure the above-described effect, in the present embodiment, the emission angle γ in the thickness direction of the display panel 2 of the detection light whose divergence is limited is expressed by the following formula (1) and the following formula (2). ) Is preferably satisfied. The shielding members 16 and 17 are preferably formed so that the emission angle γ satisfies the following formula (1) and the following formula (2).

(Equation 5)
(A / 2) tan (γ / 2) <z <b (1)

(Equation 6)
z = (a + d) tan (γ / 2) −c (2)

  In the above formulas (1) and (2), as shown in FIG. 1, a is a distance from a point on the peripheral edge of the display area 3 closest to one light source 15 to a point on another peripheral edge facing it. is there. In the present embodiment, since the shape of the display area 3 is a rectangle, a corresponds to the length of one side of the display area 3.

  Further, as shown in FIG. 1, b is an upper limit value of the height that the detection light can reach on the viewer side at the periphery of the display area 3 (the main surface on the viewer side of the transparent plate 14 is a reference). The value of b is set in advance according to the size of the display panel. For example, when the size of the display panel 2 is about 30 inches, b is set to about 5 mm to 20 mm.

  As shown in FIGS. 1 and 4, c is a distance between a plane including the center of the light emitting surface of the light source 15 and parallel to the display area 3 and the main surface on the viewer side of the transparent plate 14. In the present embodiment, the light source 15 has a spherical portion at the tip, and the vertex of the tip is the center of the light emitting surface.

  As shown in FIGS. 1 and 4, d is a line that passes through the center of the light emitting surface of one light source 15 and is perpendicular to the display region 3 and on the periphery of the display region closest to the one light source 15. The distance from the line passing through the point and perpendicular to the display area 3. That is, d corresponds to the distance between the center of the light emitting surface of the light source 15 and the display area 3 when the display panel 2 is viewed from the viewer side.

  As shown in FIG. 1, z is the height at which the detection light whose divergence is restricted by the shielding members 16 and 17 reaches the observer side at the periphery of the display region 3 (on the observer side of the transparent plate 14). The main surface is the maximum value of the standard).

  For example, when the size of the display panel 2 is 30 inches, the aspect ratio of the display area 3 is 16: 9, the length of the long side of the display area 3 is 664 mm, and the length of the short side of the display area 3 is 374 mm, The value of the emission angle γ is as follows. It is assumed that b is set to 10 mm, c is set to 5 mm, and d is set to 20 mm.

  First, the detection light source unit 7 arranged along the short side of the display area 3 will be considered. At this time, since a is 664 mm, the above formulas (1) and (2) can be rewritten as the following formulas (3) and (4).

(Equation 7)
332 tan (γ / 2) <z <10 (3)

(Equation 8)
z = 684 tan (γ / 2) −5 (4)

  Then, a range where z can be taken is determined within a range smaller than b, and a range in which γ varies when z varies within the determined range is calculated from the above (3) and (4). In this case, for example, γ = 0.8 ° to 1.3 ° is calculated. Therefore, in the detection light source unit 7 arranged along the short side of the display region 3, the shielding members 16 and 17 may be formed so that γ = 0.8 ° to 1.3 °.

  Next, the detection light source unit 7 arranged along the long side of the display area 3 will be considered. At this time, since a is 374 mm, the above equations (1) and (2) can be rewritten as the following equations (5) and (6).

(Equation 9)
187 tan (γ / 2) <z <10 (5)

(Equation 10)
z = 394 tan (γ / 2) −5 (6)

  Then, as in the case of the short side described above, a range in which z can be taken is determined within a range smaller than b, and from (5) and (6), γ varies when z varies within the determined range. The range to be calculated is calculated. In this case, for example, γ = 1.4 ° to 2.2 ° is calculated. Therefore, in the detection light source unit 7 arranged along the long side of the display area 3, the shielding members 16 and 17 may be formed so that γ = 1.4 ° to 2.2.

  Moreover, in this Embodiment, the structure of the detection light source part 7 is not limited to the example shown in FIG.1, FIG4 and FIG.5. Another example of the detection light source unit 7 will be described with reference to FIGS. 6 to 8 are cross-sectional views illustrating other examples of the detection light source unit that can be used in the display device according to the present embodiment. 6 to 8 show an enlarged part of the display device as in FIG.

  In the example of FIG. 6, a light shielding member 17 serving as a limiting member is disposed only on the display region 3 side of the light source 15. Further, the light source 15 is arranged so that the direction of the highest luminance of the detection light emitted from the light source 15 (the direction indicated by the arrow in the figure) is gradually away from the display area 3 on the back side of the display area 3.

  As described above, in the example of FIG. 6, the height at which the detection light can reach the observer side on the periphery of the display region 3 is limited by inclining the emission direction of the light source 15 toward the back surface side of the display panel 2. . On the other hand, the incidence of the detection light on the imaging unit 4 is limited by the light shielding member 17. Therefore, even when the example of FIG. 6 is used, the emission angle of the detection light emitted from the light source 15 in the thickness direction of the display panel 2 is changed from the angle α to the angle as in the examples shown in FIGS. It is narrowed to γ (α> γ).

  In the example of FIG. 7, the limiting member 16 is disposed only on the transparent plate 14 side of the light source 15. Further, the light source 15 is arranged so that the direction of the highest luminance of the detection light emitted from the light source 15 is gradually away from the display area 3 on the viewer side of the display area 3.

  As described above, in the example of FIG. 7, unlike the example of FIG. 6, the height at which the detection light can reach the observer side on the periphery of the display region 3 is limited by the light shielding member 16. Further, unlike the example of FIG. 6, the incidence of the detection light on the imaging unit 4 is limited by inclining the emission direction of the light source 15 toward the observer side of the display panel 2. Also in the case of using the example of FIG. 7, as in the example shown in FIG. 6, the emission angle of the detection light emitted from the light source 15 in the thickness direction of the display panel 2 is from the angle α to the angle γ (α> γ). It is narrowed to.

  In the example of FIG. 8, unlike the examples shown in FIGS. 1, 4, 5, 6, and 7, a lens element 23 is used as a limiting member. The lens element 23 is arranged so that its optical axis coincides with the direction in which the detection light has the highest luminance. According to the example of FIG. 8, since the detection light emitted from the light source 15 is converged by the lens element 23, the emission angle of the detection light emitted from the light source 15 in the thickness direction of the display panel 2 is from the angle α. It is narrowed to γ (α> γ).

  However, in the example of FIG. 8, the spread of the detection light in the surface direction is also limited. Therefore, in the case where the example of FIG. 8 is adopted, it is preferable that the pitch between the light sources 15 is made smaller and more light sources 15 are mounted than in the case where the examples of FIGS.

  As described above, when the detection light source unit 7 shown in FIGS. 6 to 8 is used, the detection light is emitted as in the case of using the detection light source unit 7 shown in FIGS. The corner can be reduced. Therefore, even in these cases, it is possible to suppress even an object located at a position away from the display area 3 of the display panel 2 and to use the display device as a touch panel. In addition, sensing accuracy can be improved by suppressing variations in the range in which the detection light reaches. Furthermore, since it is possible to suppress the detection light from directly entering the imaging unit 4, it is possible to suppress deterioration in imaging quality.

  Further, the wavelength of the detection light emitted from the light source 15 is not particularly limited, but in the present embodiment, it is preferable that the wavelength is set in a region other than the visible region as described above. Specifically, the wavelength of the detection light is set to 700 nm or more, preferably 800 nm or more, particularly preferably 850 nm or more. This is because when the display panel 2 is set to such a range, when the display panel 2 is a liquid crystal display panel, it is possible to increase the transmittance of detection light with respect to the color filters and polarizing plates constituting the liquid crystal display panel. 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.

  In addition, when 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. Further, as the visible light here, in the case where the display panel 2 is a liquid crystal display panel, illumination light emitted from a backlight and passing through the display panel 2 or light from the outside of the display device can be mentioned. Therefore, in the present embodiment, as the optical filter 31 shown in FIG. 3, it is preferable to use a high-pass filter that transmits only light having a wavelength of 700 nm or more, preferably 800 nm or more, particularly preferably 850 nm or more.

  As described above, the 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 a display device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing the positional relationship of the main parts of the display device shown in FIG. FIG. 3 is a cross-sectional view illustrating a schematic configuration of an imaging unit provided in the display device illustrated in FIGS. 1 and 2. 4 is an enlarged partial cross-sectional view of a part of the cross-sectional view shown in FIG. FIG. 5 is a diagram illustrating a schematic configuration of the detection light source unit illustrated in FIGS. 1 and 2, in which FIG. 5A is a cross-sectional view cut along the emission direction of the detection light, and FIG. FIG. FIG. 6 is a cross-sectional view illustrating another example of the detection light source unit that can be used in the display device according to the present embodiment. FIG. 7 is a cross-sectional view illustrating another example of the detection light source unit that can be used in the display device according to the present embodiment. FIG. 8 is a cross-sectional view illustrating another example of the detection light source unit that can be used in the display device according to the present embodiment.

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 Imaging part 5 Backlight device 6 Fluorescent lamp 7 Detection light source part 8 Case 9 Diffusion plate 10 Diffusion sheet 11 Prism sheet 12 Reflection / polarization sheet 13 Optical layer 14 Transparent plate 15 Light source of detection light source section 16, 17 Restriction member (shielding member)
DESCRIPTION OF SYMBOLS 18 Frame of detection light source part 19 Fixing member 20 Light guide path 21 Frame of display apparatus 22 Space 30 between transparent plate and display area 30, 35 Lens element (imaging optical system)
30a, 35a Optical axis 31 Optical filter 32 Solid-state imaging device 32a Normal line passing through center of light-receiving surface of solid-state imaging device 33, 36 Frame of imaging unit

Claims (11)

A display panel having optical transparency, an imaging unit having an imaging optical system, and a detection light source unit having a light source for emitting detection light to the viewer side of the display panel,
The detection light source unit is disposed around a display area on the viewer side of the display panel, and includes a limiting member that limits the divergence of the detection light in the thickness direction of the display panel,
The imaging unit receives the detection light that is incident on the display panel from the observer side and passes through the display panel and the imaging optical system, and images the state of the display panel on the observer side. A display device characterized by that. On the viewer side of the display panel, comprising a transparent plate covering the display area of the display panel,
The transparent plate is disposed so that a space is formed between the display area and the display area.
The display device according to claim 1, wherein the detection light source unit is arranged in the space so that the detection light is emitted from the space to an observer side of the transparent plate.   The display device according to claim 1, wherein the restricting member is a light shielding member disposed on at least one of the light source on the display region side and the opposite side thereof. The light shielding member serving as the limiting member is disposed on the display region side and the opposite side of the light source,
The display device according to claim 3, wherein the light source is disposed such that a direction in which the emitted detection light has the highest luminance is parallel to the display area. The light shielding member serving as the limiting member is disposed on the display area side of the light source,
4. The display device according to claim 3, wherein the light source is arranged such that a direction in which the emitted detection light has the highest luminance is a direction gradually moving away from the display area on the back side of the display area. The light shielding member serving as the limiting member is disposed on the opposite side of the display area side of the light source,
The display device according to claim 3, wherein the light source is arranged so that a direction in which the emitted detection light has the highest luminance is a direction gradually moving away from the display region on the viewer side. The limiting member is a lens element;
The display device according to claim 1, wherein the lens element is arranged so that an optical axis thereof coincides with a direction in which the luminance of the emitted detection light is highest. A is a distance from a point on the periphery of the display area closest to the light source to a point on the other edge opposite to the point
The upper limit value of the height from the main surface on the observer side of the transparent plate that can be reached on the observer side at the periphery of the display region is b,
The distance between the surface including the center of the light emitting surface of the light source and parallel to the display area and the main surface on the viewer side of the transparent plate is c,
A distance between a line passing through the center of the light emitting surface of the light source and perpendicular to the display area and a line passing through a point on the periphery of the display area closest to the light source and perpendicular to the display area d
When the maximum value of the height from the main surface on the observer side of the transparent plate, which is reached on the observer side at the periphery of the display region, is z,
The emission angle γ in the thickness direction of the display panel of the detection light, the divergence of which is limited by the limiting member, is set so as to satisfy the following formula (1) and the following formula (2). The display device described.
(Equation 1)
(A / 2) tan (γ / 2) <z <b (1)
(Equation 2)
z = (a + d) tan (γ / 2) −c (2) The light source is a light emitting diode that emits light having a wavelength of 700 nm or more;
The display device according to claim 1, wherein the imaging unit receives only light having a wavelength of 700 nm or more. The light source emits light having a wavelength of 800 nm to 1000 nm;
The display device according to claim 9, wherein the imaging unit receives only light having a wavelength of 800 nm or more. The display device according to claim 1, wherein the display panel is a liquid crystal display panel or an EL display panel.

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