DISPLAY DEVICE

According to one embodiment, a display device includes a first transparent substrate, a display panel, a first fixing member, and a first light source unit. The first transparent substrate has a first light incident surface which is a side surface, and is formed to be curved. The display panel has flexibility. The first fixing member fixes the display panel to the first transparent substrate. The first light source unit is opposed to the first light incident surface to emit light to the first light incident surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-088019, filed May 29, 2023, the entire contents of which are incorporated herein by reference.

FIELD

BACKGROUND

Recently, display devices comprising a polymer dispersed liquid crystal (hereinafter referred to as “PDLC”) panel capable of switching a diffusing state of diffusing incident light and a transmitting state of allowing the incident light to be transmitted, displaying an image, and allowing a background to be transmitted and the image to be visually recognized, have been proposed. In such a display device, one frame period includes sub-frame periods, and multi-color display is implemented by displaying the image while changing a display color in each of the sub-frame period.

DETAILED DESCRIPTION

In general, according to one embodiment, there is provided a display device comprising: a first transparent substrate having a first main surface, a second main surface on a side opposite to the first main surface, and a first light incident surface, which is a side surface located between the first main surface and the second main surface, and being formed to be curved; a display panel having a display area where an image is displayed and external light is transmitted, being opposed to the first main surface of the first transparent substrate, and having flexibility; a first fixing member located between the first transparent substrate and the display panel to fix the display panel to the first transparent substrate; and a first light source unit opposed to the first light incident surface of the first transparent substrate to emit light to the first light incident surface.

According to another embodiment, there is provided a display device comprising: a non-flexible first transparent substrate having a curved main surface; a flexible display panel opposed to the main surface of the first transparent substrate and fixed to the first transparent substrate; and a light source opposed to a first side surface of the first transparent substrate to emit light to the first side surface. A side of the display panel, which is opposite to the first transparent substrate, is visually recognizable from a side of the first transparent substrate.

In each of the embodiments, a display device employing polymer dispersed liquid crystal will be described as an example of the display device.

First Embodiment

FIG.1is a plan view showing a configuration example of a display device DSP according to the present embodiment.

As shown inFIG.1, a first direction X and a second direction Y are directions intersecting each other, and a third direction Z is a direction intersecting the first direction X and the second direction Y. The first direction X corresponds to the row direction while the second direction Y corresponds to the columnar direction. For example, the first direction X, the second direction Y, and the third direction Z are orthogonal to one another but may intersect at an angle other than 90 degrees. In the present specification, a direction forwarding a tip of an arrow indicating the third direction Z is called an upward direction (or, more simply, upwardly) and a direction forwarding oppositely from the tip of the arrow is called a downward direction (or, more simply, downwardly).

The display device DSP comprises the display panel PNL, wiring boards F1, F2, F4, and F5, and the like. The display panel PNL includes a display area DA on which images are displayed and a frame-shaped non-display area NDA surrounding the display area DA. The display area DA includes n gate lines G (G1to Gn), m source lines S (S1to Sm), and the like. Incidentally, each of n and m is a positive integer, and n may be equal to or different from m. The plurality of gate lines G extend in the first direction X and are arranged to be spaced apart in the second direction Y. In other words, the plurality of gate lines G extend in the row direction. The plurality of source lines S extend in the second direction Y and are arranged to be spaced apart in the first direction X. The display panel PNL includes end portions E1and E2along the first direction X, and end portions E3and E4along the second direction Y.

The wiring board F1includes a gate driver GD. The plurality of gate lines G are connected to the gate driver GD. The wiring board F2includes a source driver SD. The plurality of source lines S are connected to the source driver SD. Each of the wiring boards F1and F2is connected to the display panel PNL and the wiring board F4. The wiring board F5includes a timing controller TC, a power supply circuit PC, and the like. The wiring board F4is connected to a connector CT of the wiring board F5. Incidentally, the wiring boards F1and F2may be replaced with single wiring boards. Alternatively, the wiring boards F1, F2, and F4may be replaced with single wiring boards. The gate driver GD, the source driver SD, and the timing controller TC described above constitute the control unit CON of the present embodiment, and the control unit CON is configured to control the drive of each of the plurality of gate lines G, the plurality of source lines S, a plurality of pixel electrodes to be described later, a common electrode to be described later, and the light source unit to be described later.

FIG.2is a developed cross-sectional view showing the display device DSP shown inFIG.1. Incidentally, an actual first transparent substrate ME1and an actual display panel PNL are curved. Main portions alone in the cross-section of the display device DSP in a Y-Z plane defined by the second direction Y and the third direction Z will be described here.

As shown inFIG.2, the display device DSP comprises a cover panel CO1. The cover panel CO1comprises the first transparent substrate ME1. The first transparent substrate ME1is a cover glass and is formed of glass. The first transparent substrate ME1is a non-flexible substrate. The first transparent substrate ME1overlaps with at least the entire display area DA.

The first transparent substrate ME1has a first main surface Sa1, a second main surface Sa2, a side surface Sb1, and a side surface Sb2. The second main surface Sa2is located on a side opposite to the first main surface Sa1. The side surface Sb1is located between the first main surface Sa1and the second main surface Sa2. The side surface Sb1is a first light incident surface. The side surface Sb2is located between the first main surface Sa1and the second main surface Sa2and is also located on a side opposite to the side surface Sb1. In the present embodiment, the side surface Sb1and the side surface Sb2are located in the non-display area NDA. An angle between the first main surface Sa1and the side surface Sb1is referred to as θ1. In the present embodiment, the angle θ1is 90 degrees.

The display panel PNL has a display area DA where images are displayed and external light is transmitted. The display panel PNL is opposed to the first main surface Sa1of the first transparent substrate ME1. The display panel PNL has flexibility. The display panel PNL comprises a first substrate SUB1, a second substrate SUB2, a liquid crystal layer30serving as a display function layer, and the like. The first substrate SUB1comprises a transparent first basement10, a pixel electrode11, an alignment film12, and the like. The second substrate SUB2comprises a transparent second basement20, a common electrode21, an alignment film22, and the like. The second basement20is located between the first basement10and the first transparent substrate ME1. The pixel electrodes11and the common electrode21are formed of, for example, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The liquid crystal layer30is located in at least the display area DA.

The liquid crystal layer30is located between the first basement10(first substrate SUB1) and the second basement20(second substrate SUB2). More specifically, the liquid crystal layer30is located between the alignment films12and22. The liquid crystal layer30contains polymer dispersed liquid crystal. The liquid crystal layer30of the present embodiment uses reverse mode polymer dispersed liquid crystal (R-PDLC). The liquid crystal layer30maintains parallelism of incident light when the applied voltage is low or scatters the incident light when the applied voltage is high. The first substrate SUB1and the second substrate SUB2are bonded to each other by a sealing material40. The first substrate SUB1comprises an extending portion EX that extends farther in the second direction Y than a side surface Sc1of the second basement20.

A first adhesive sheet AD1is located between the first transparent substrate ME1and the display panel PNL and adheres the display panel PNL to the first transparent substrate ME1. The first adhesive sheet AD1contacts and sticks to the first transparent substrate ME1on one side and contacts and sticks to the display panel PNL on the other side. The first adhesive sheet AD1overlaps with at least the entire display area DA. The first adhesive sheet AD1is formed of an optical clear adhesive (OCA) as a solid adhesive. However, the first adhesive sheet AD1may be formed of a material other than OCA, for example, optically clear resin (OCR). Furthermore, the display panel PNL and the first transparent substrate ME1may be bonded. In other words, the present embodiment includes a structure in which the display panel PNL and the first transparent substrate ME1are fixed. Therefore, the first adhesive sheet AD1is also referred to as a first fixing member. In addition, no air layer is desirably located between the display panel PNL and the first transparent substrate ME1.

The wiring boards F1and F2are connected to the extending portion EX of the first substrate SUB1.

A first light source unit LU1is located in the non-display area NDA outside the display area DA. The first light source unit LU1comprises a light emitting element LS, a wiring board F6, and the like. The light emitting element LS is connected to the wiring board F6and located on the extending portion EX. The light emitting element LS includes a light emitting portion (light emitting surface) EM that is opposed to the side surface Sb1to emit light to the side surface Sb1.

The illumination light emitted from the light emitting portion EM is made incident on the side surface Sb1and propagates through the first transparent substrate ME1(cover panel CO1), the first adhesive sheet AD1, and the display panel PNL, as described below. In the present embodiment, the light emitting portion EM is also opposed to the side surface Sc1of the second basement20. The illumination light emitted from the light emitting portion EM is also made incident on the side surface Sc1.

Each of the first basement10and the second basement20is formed of glass. The first basement10has a thickness Tb1and the second basement20has a thickness Tb2. Each of the thickness Tb1and the thickness Tb2is 0.2 mm or less. More specifically, each of the thickness Tb1and the thickness Tb2is 0.1 to 0.2 mm. In the present embodiment, each of the thickness Tb1and the thickness Tb2is 0.15 mm. The display panel PNL can be made flexible by forming the first basement10and the second basement20to be thin.

The first transparent substrate ME1has a thickness Ta and the display panel PNL has a thickness Tb, in the direction in which the first transparent substrate ME1and the display panel PNL are aligned. The thickness Tb includes the thickness Tb1, the thickness Tb2, the thickness of the liquid crystal layer30, and the like. The thickness Ta of the first transparent substrate ME1is desirably larger than the thickness Tb of the display panel PNL. In the present embodiment, the thickness Ta of the first transparent substrate ME1is greater than the thickness Tb of the display panel PNL. The thickness Ta is 0.7 to 3.0 mm.

As described above, even if the thickness Tb2of the second basement20is reduced, the first transparent substrate ME1has a thickness Ta greater than the thickness Tb2. The first light source unit LU1can emit light to the side surface Sb1of the first transparent substrate ME1. Therefore, the user can visually recognize the display images of the display device DSP desirably as compared to the case where the first light source unit LU1emits light to the side surface Sc1of the second basement20. For example, the contrast ratio of the display device DSP can be increased.

In the present embodiment, the first light source unit LU1emits light not only to the side surface Sb1but also to the side surface Sc1. Therefore, the user can visually recognize the display image of the display device DSP further desirably.

FIG.3is a diagram showing main constituent elements of the display device DSP shown inFIG.1.

As shown inFIG.3, the display device DSP comprises a controller CNT represented by a dashed line in the drawing. The controller CNT includes a timing controller TC, a gate driver GD, a source driver SD, a Vcom circuit VC, a light source driver LSD, and the like.

The timing controller TC generates various signals, based on image data, a synchronization signal, and the like input from the outside. In one example, the timing controller TC outputs a video signal generated by executing predetermined signal processing, based on the image data, to the source driver SD. In addition, the timing controller TC outputs the control signals generated based on the synchronization signals to each of the gate driver GD, the source driver SD, the Vcom circuit VC, and the light source driver LSD. The timing controller TC will be described below in detail.

The display area DA represented by a two-dotted-chain line in the drawing includes a plurality of pixels PX. Each of the pixels PX comprises a switching element SW and the pixel electrode11. The switching element SW is formed of, for example, a thin-film transistor. The switching element SW is electrically connected to the gate line G and the source line S. The plurality of pixel electrodes11are located in the display area DA and arrayed in a matrix. For this reason, for example, the plurality of pixel electrodes11are provided in a plurality of rows. The pixel electrode11is connected to the source line S via the switching element SW. The common electrode21is located in the display area DA. The common electrode21is opposed to the plurality of pixel electrodes11. Incidentally, unlike the present embodiment, the common electrode21may be divided for each of at least one pixel PX and connected to each common line, and a common voltage may be applied to the divided common electrodes.

A gate signal is supplied from the gate driver GD to each of the gate lines G. A video signal (image signal) is supplied from the source driver SD to each of the source lines S. A common voltage Vcom is supplied from the Vcom circuit VC to the common electrode21. The video signal supplied to the source line S is applied to the pixel electrode11connected to the switching element SW in a period in which the switching element SW becomes a conductive state based on the gate signal supplied to the gate line G. In the following description, supplying a video signal to the pixel electrode11to form a potential difference between the pixel electrode11and the common electrode21may be described as writing a video signal (or applying a voltage) to the pixel PX comprising the pixel electrode11.

The first light source unit LU1is configured to emit light to the liquid crystal layer30. In the present embodiment, the first light source unit LU1is configured to emit light of a color other than achromatic color to the liquid crystal layer30. The first light source unit LU1comprises light emitting elements LS of a plurality of colors. For example, the first light source unit LU1comprises a light emitting element (first light emitting element) LSR which emits light of a first color to the liquid crystal layer30, a light emitting element (second light emitting element) LSG which emits light of a second color to the liquid crystal layer30, and a light emitting element (third light emitting element) LSB which emits light of a third color to the liquid crystal layer30. It is needless to say that the first, second, and third colors are different from one another. In the present embodiment, the first color is red, the second color is green, and the third color is blue.

The light source driver LSD controls lighting periods of the light emitting elements LSR, LSG, and LSB. As will be described in detail later, in a drive system where one frame period includes a plurality of sub-frame periods, at least one of the three light emitting elements LSR, LSG, and LSB is turned on in each sub-frame, and the color of the illumination light is switched in each sub-frame.

A configuration example of the display device comprising the liquid crystal layer30which is a polymer dispersed liquid crystal layer will be described below.

FIG.4Ais a diagram showing a part of the display panel PNL, schematically illustrating the liquid crystal layer30in a transparent state.

As shown inFIG.4A, the liquid crystal layer30contains a liquid crystalline polymer31that is a streaky polymer, and liquid crystalline molecules32. The liquid crystalline polymer31can be obtained by, for example, polymerizing liquid crystalline monomer in a state of being aligned in a predetermined direction by the alignment restriction force of the alignment films12and22. The liquid crystalline molecules32are dispersed in the liquid crystalline monomer, and are aligned in a predetermined direction depending on the alignment direction of the liquid crystalline monomer when the liquid crystalline monomer is polymerized. In the present embodiment, the alignment films12and22are horizontal alignment films that perform initial alignment of the liquid crystalline monomer and the liquid crystalline molecules32along an X-Y plane defined by the first direction X and the second direction Y. The liquid crystalline molecules32are positive liquid crystalline molecules having positive dielectric anisotropy.

Unlike the present embodiment, however, the alignment films12and22may be vertical alignment films that perform initial alignment of the liquid crystalline monomer and the liquid crystalline molecules32along the third direction Z. Alternatively, the liquid crystalline molecules32may be negative liquid crystalline molecules having negative dielectric anisotropy.

The liquid crystalline polymer31and the liquid crystalline molecules32have equivalent optical anisotropy. Alternatively, the liquid crystalline polymer31and the liquid crystalline molecules32have approximately equivalent refractive anisotropy. In other words, an ordinary refractive index and an extraordinary refractive index of each of the liquid crystalline polymer31and the liquid crystalline molecules32are approximately equal to each other. Incidentally, for both the ordinary refractive index and the extraordinary refractive index, values of the liquid crystalline polymer31and the liquid crystalline molecules32may not completely match each other, and a deviation caused by an error in manufacturing or the like is allowed. In addition, the liquid crystalline polymer31and the liquid crystalline molecules32are different in responsiveness to the electric field. In other words, the responsiveness of the liquid crystalline polymer31to the electric field is lower than the responsiveness of the liquid crystalline molecules32to the electric field.

The example shown inFIG.4Acorresponds to a state in which no voltage is applied to the liquid crystal layer30(for example, a state in which a potential difference between the pixel electrode11and the common electrode21is zero) or a state in which a second transparent voltage to be described below is applied to the liquid crystal layer30.

As shown inFIG.4A, an optical axis Ax1of the liquid crystalline polymer31and an optical axis Ax2of the liquid crystalline molecules32are parallel to each other. In the example illustrated, each of the optical axis Ax1and the optical axis Ax2is parallel to the first direction X. The optical axis corresponds to a line parallel to a direction of travel of the light beam in which the refractive indexes indicate one value irrespective of the direction of polarization.

As described above, since the liquid crystalline polymer31and the liquid crystalline molecules32have approximately equal refractive anisotropy and the optical axes Ax1and Ax2are parallel to each other, there is almost no refractive index difference between the liquid crystalline polymer31and the liquid crystalline molecules32in all directions including the first direction X, the second direction Y, and the third direction Z. For this reason, light beams L1made incident on the liquid crystal layer30in the third direction Z are transmitted without being substantially scattered in the liquid crystal layer30. The liquid crystal layer30can maintain the parallelism of the light beams L1. Similarly, light beams L2and L3made incident in a direction oblique with respect to the third direction z are not substantially scattered in the liquid crystal layer30, either. High transparency can be therefore obtained. The state illustrated inFIG.4Ais referred to as a “transparent state”.

FIG.4Bis a diagram showing a part of the display panel PNL, schematically showing the liquid crystal layer30in a scattered state.

As shown inFIG.4B, as described above, the responsiveness of the liquid crystalline polymer31to the electric field is lower than the responsiveness of the liquid crystalline molecule32to the electric field. For this reason, in a state in which a voltage (scattering voltage to be described below) higher than each of the second transparent voltage and a first transparent voltage to be described below is applied to the liquid crystal layer30, the alignment direction of the liquid crystalline molecules32is changed in accordance with the electric field while the alignment direction of the liquid crystalline polymer31is hardly changed. In other words, as shown in the drawing, the optical axis Ax1is substantially parallel to the first direction X while the optical axis Ax2is oblique to the first direction X. For this reason, the optical axes Ax1and optical axes Ax2intersect each other. Therefore, a large refractive index difference is made between the liquid crystalline polymer31and the liquid crystalline molecules32in all the directions including the first direction X, the second direction Y, and the third direction Z. The light beams L1to L3made incident on the liquid crystal layer30are thereby scattered in the liquid crystal layer30. The state shown inFIG.4Bis referred to as a “scattered state”.

The control unit CON switches the state of the liquid crystal layer30to at least one of the transparent state and the scattered state.

FIG.5Ais a developed cross-sectional view showing the display panel PNL in a case where when the liquid crystal layer30is in a transparent state and the first transparent substrate ME1, together with the light emitting element LS. As shown inFIG.5A, the first basement10has a lower surface10B and the second basement20has an upper surface20T. Illumination light emitted from the light emitting element LS is made incident on the cover panel CO1and the display panel PNL from the side surface Sb1of the first transparent substrate ME1and the side surface Sc1of the second basement20.

For example, the illumination light L11emitted from the light emitting element LS and made incident on the side surface Sb1of the first transparent substrate ME1propagates through the first transparent substrate ME1, the first adhesive sheet AD1, the second basement20, the liquid crystal layer30, the first basement10, and the like. When the liquid crystal layer30is in a transparent state, the illumination light L11is hardly scattered by the liquid crystal layer30and therefore rarely leaks out from the lower surface10B of the first basement10and the second main surface Sa2of the first transparent substrate ME1.

An external light beam L12made incident on the display panel PNL is transmitted and hardly scattered in the liquid crystal layer30. In other words, external light made incident on the display panel PNL from the lower surface10B is transmitted to the second main surface Sa2of the first transparent substrate ME1, and external light made incident from the second main surface Sa2is transmitted to the lower surface10B. For this reason, when the display device DSP is observed from the second main surface Sa2side, the user can visually recognize a background on the lower surface10B side through the display panel PNL. Similarly, when the display device DSP is observed from the lower surface10B side, the user can visually recognize a background on the second main surface Sa2side through the display panel PNL.

FIG.5Bis a developed cross-sectional view showing the display panel PNL in a case where the liquid crystal layer30is in a scattered state and the first transparent substrate ME1, together with the light emitting element LS. As shown inFIG.5B, illumination light emitted from the light emitting element LS is made incident on the cover panel CO1and the display panel PNL from the side surface Sb1of the first transparent substrate ME1and the side surface Sc1of the second basement20.

For example, the illumination light L21emitted from the light emitting element LS and made incident on the side surface Sb1of the first transparent substrate ME1propagates through the first transparent substrate ME1, the first adhesive sheet AD1, the second basement20, the liquid crystal layer30, the first basement10, and the like. In the example illustrated, since the liquid crystal layer30between a pixel electrode11α and the common electrode21(i.e., a liquid crystal layer to which a voltage applied between the pixel electrode11α and the common electrode21is applied) is in a transparent state, the illumination light beam L21is hardly scattered in an area opposed to the pixel electrode11α, in the liquid crystal layer30.

In contrast, since the liquid crystal layer30between a pixel electrode11β and the common electrode21(i.e., a liquid crystal layer to which a voltage applied between the pixel electrode11β and the common electrode21is applied) is in the scattered state, the illumination light beam L21is scattered in an area opposed to the pixel electrode11β, in the liquid crystal layer30. A scattered light beam L211of the illumination light beam L21is emitted to the outside from the second main surface Sa2, and a scattered light beam L212is emitted to the outside from the lower surface10B.

At a position which overlaps with the pixel electrode11α, an external light beam L22made incident on the display panel PNL is transmitted and hardly scattered in the liquid crystal layer30, similarly to the external light beam L12shown inFIG.5A. At a position which overlaps with the pixel electrode11β, a light beam L231of an external light beam L23made incident from the lower surface10B is scattered in the liquid crystal layer30and then transmitted through the second main surface Sa2. In addition, a light beam L241of an external light beam L24made incident from the second main surface Sa2is scattered in the liquid crystal layer30and then transmitted through the lower surface10B.

For this reason, when the display device DSP is observed from the second main surface Sa2side, a color of the illumination light beam L21can be visually recognized at a position which overlaps with the pixel electrode11B. In addition, since the external light beam L231is transmitted through the display panel PNL, the background on the lower surface10B side can also be visually recognized through the display panel PNL. Similarly, when the display device DSP is observed from the lower surface10B side, a color of the illumination light beam L21can be visually recognized at a position which overlaps with the pixel electrode11β. In addition, since the external light beam L241is transmitted through the display panel PNL, the background on the second main surface Sa2side can also be visually recognized through the display panel PNL. At a position which overlaps with the pixel electrode11α, the color of the illumination light beam L21can hardly be recognized visually and the background can be visually recognized through the display panel PNL since the liquid crystal layer30is in the transparent state.

FIG.6is a graph showing the scattering characteristic of the liquid crystal layer30, indicating a relationship between the luminance and a voltage VLC applied to the liquid crystal layer30. In this example, the luminance corresponds to luminance of the scattered light beam L211obtained when the illumination light beam L21emitted from the light emitting element LS is scattered in the liquid crystal layer30as shown in, for example,FIG.5B. This luminance indicates a scattering degree of the liquid crystal layer30from the other viewpoint.

As shown inFIG.6, when the voltage VLC is increased from 0V, the luminance is rapidly increased from approximately 8V and saturated at approximately 20V. The luminance is also slightly increased when the voltage VLC is in a range from 0V to 8V. In the present embodiment, an area surrounded by a two-dot-chain line, i.e., a voltage in a range from 8V to 16V is used for reproduction of gradation (for example, 256 gradation) of each pixel PX. The voltage in a range 8V<VLC≤16V is hereinafter referred to as a scattering voltage. In addition, in the present embodiment, an area surrounded by a one-dot-chain line, i.e., the voltage in a range 0V≤VLC≤8V is referred to as a transparent voltage. A transparent voltage VA includes the first transparent voltage VA1and the second transparent voltage VA2described above. Incidentally, the lower and upper limits of the scattering voltage VB and the transparent voltage VA are not limited to this example and can be determined as appropriate according to the scattering characteristics of the liquid crystal layer30.

The degree of scattering in a case where the degree of scattering of the light made incident on the liquid crystal layer30is the highest when the scattering voltage VB is applied to the liquid crystal layer30is assumed to be 100%. In this example, the degree of scattering in a case of applying the scattering voltage VB of 16V to the liquid crystal layer30is assumed to be 100%. For example, the transparent voltage VA can be defied as a voltage in a range of the voltage VLC where the degree of scattering (luminance) is less than 10%. Alternatively, the transparent voltage VA can also be defined as the voltage VLC lower than or equal to a voltage (8V in the example ofFIG.6) corresponding to the lowest gradation.

In addition, the transparent voltage VA (first transparent voltage VA1and second transparent voltage VA2) may be different from that in the example shown inFIG.6. For example, the first transparent voltage VA1may be a voltage with the degree of scattering in a range higher than or equal to 10% and lower than or equal to 50%. In addition, the second transparent voltage VA2may be a voltage with the degree of scattering in a range lower than 10%.

Incidentally, the graph shown inFIG.6is applicable to a case where the polarity of the voltage applied to the liquid crystal layer30is positive polarity (+) and negative polarity (−). In the latter case, the voltage VLC is an absolute value of the negative-polarity voltage.

The polarity inversion drive scheme of inverting the polarity of the voltage applied to the liquid crystal layer30can be applied to the display device DSP.FIG.7A,FIG.7B, andFIG.7Care diagrams showing an outline of the polarity inversion drive scheme.

FIG.7Ashows a one-line inversion drive scheme of inverting the positive polarity (+) and the negative polarity (−) of the voltage applied to the liquid crystal layer30(i.e., the voltage written to the pixel PX) in each group of pixels PX (one line) connected to one gate line G. In such a drive method, for example, the polarity of the common voltage supplied to the common electrode21and the polarity of the video signal supplied from the source driver SD to the source line S (polarity of the source line voltage) are inverted in each horizontal period in which the gate driver GD supplies the gate signal to the gate line G. In the same horizontal period, the polarity of the common voltage and the polarity of the video signal are, for example, opposite to each other.

FIG.7Bshows a two-line inversion drive scheme of inverting the positive polarity (+) and the negative polarity (−) of the voltage to be applied to the liquid crystal layer30in every two lines. The present invention is not limited to the example shown inFIG.7AandFIG.7B, but the polarity may be inverted in every three or more lines.

FIG.7Cshows a frame-inversion drive scheme of inverting the positive polarity (+) and the negative polarity (−) of the voltage applied to the liquid crystal layer30in each frame period for displaying an image corresponding to one piece of image data. In such a drive method, for example, the polarity of the common voltage and the polarity of the video signal are inverted in each frame period. In the same frame period, for example, the polarity of the common voltage and the polarity of the video signal are opposite to each other.

FIG.8is a chart showing an example of the common voltage Vcom supplied to the common electrode21and the source line voltage Vsig supplied to the source line S (or the pixel electrode11) in the display drive to which the one-line inversion drive scheme shown inFIG.7Ais applied.

As shown inFIG.8, a waveform corresponding to a maximum value (max) of gradation and a waveform corresponding to a minimum value (min) of gradation are illustrated with respect to the source line voltage Vsig. The waveform of the source line voltage Vsig (min) is represented by a solid line, the waveform of the common voltage Vcom is represented by a two-dot-chain line, and the waveform of the source line voltage Vsig (max) is represented by a broken line. In the example of this chart, the polarities of the common voltage Vcom and the source line voltage Vsig (cf., the waveform of the maximum value) are inverted in each frame period Pf. A reference voltage Vsig-c is, for example, 8V. The lower limit is 0V and the upper limit is 16V in each of the common voltage Vcom and the source line voltage Vsig.

However, when the frame period Pf includes a plurality of sub-frame periods, the polarity of the common voltage Vcom and the polarity of the source line voltage Vsig may be inverted in each frame period Pf, or may be inverted in each field period.

The polarity inversion drive scheme including not only the example shown inFIG.8, but the example ofFIG.9to be described later will be focused. When the drive voltage to be applied to the liquid crystal layer30(voltage to be written to the pixel PX) has a positive polarity, a difference (Vsig-Vcom) between the source line voltage Vsig and the common voltage Vcom becomes 0V or a positive voltage value. In contrast, when the drive voltage to be applied to the liquid crystal layer30(voltage to be written to the pixel PX) has negative polarity, the difference (Vsig-Vcom) between the source line voltage Vsig and the common voltage Vcom is 0V or a negative voltage value.

The polarity inversion drive scheme shown inFIG.8will be focused. In a period in which the positive-polarity voltage is written to the pixel PX, the common voltage Vcom becomes 0V, and the source line voltage Vsig becomes a voltage value corresponding to gradation indicated by image data in a range of 8V or more and 16V or less. In contrast, in a period in which the negative-polarity voltage is written to the pixel PX, the common voltage Vcom becomes 16V, and the source line voltage Vsig becomes a voltage value corresponding to gradation indicated by image data in a range of 0V or more and 8V or less. In other words, in any case, the voltage higher than or equal to 8V and lower than or equal to 16V is applied between the common electrode21and the pixel electrode11.

As shown inFIG.6, even when the voltage VLC applied to the liquid crystal layer30is 8V, i.e., the first transparent voltage VA1is applied to the liquid crystal layer30, the liquid crystal layer30has the degree of scattering of approximately 0 to 10%. Therefore, even when the source line voltage Vsig is set to the minimum value of the gradation, the external light made incident on the display panel PNL is slightly scattered, and the visibility of the background of the display panel PNL may be reduced.

For this reason, the visibility of the background of the display panel PNL can be improved by applying the transparent drive of making the voltage between the pixel electrode11and the common electrode21smaller than the lower limit of gradation to the sequence of image display.

Then, a relationship between the common voltage Vcom and the output of the source driver SD will be described.

When a withstand voltage of the source driver SD is low, the common voltage Vcom is inversely driven to increase the liquid crystal applied voltage. At this time, the source driver SD can simultaneously output only one of the positive-polarity source line voltage Vsig (for example, reference voltage Vsig-c to 16V) and the negative-polarity source line voltage Vsig (for example, 0V to reference voltage Vsig-c). In addition, the polarity of the common voltage Vcom is opposite to the polarity of the output of the source driver SD.

However, when the source driver SD of a high withstand voltage is used, the relationship between the source line voltage Vsig and the common voltage Vcom may be the same as the above-described relationship, but may also be a relationship to be described below. In other words, the common voltage Vcom is fixed to 0V, and the source line voltage Vsig output from the source driver SD is in a range between 0 and +16V at the positive polarity or a range between-16 and 0V at the negative polarity.

FIG.9is a chart showing an example of the common voltage Vcom and the source line voltage Vsig in the transparent drive. The waveform of the source line voltage Vsig is represented by a solid line, and the waveform of the common voltage Vcom is represented by a two-dot-chain line.

As shown inFIG.9, the common voltage Vcom is switched alternately to 0V and 16V in each frame period Pf, similarly to the example shown inFIG.8. In the transparent drive, the voltage value of the source line voltage Vsig matches the common voltage Vcom (Vsig=Vcom=0V or Vsig=Vcom=16V) in each frame period Pf. InFIG.9, in view of a relationship in illustration between the source line voltage Vsig and the common voltage Vcom, both of them are slightly shifted. For this reason, the voltage of 0V is applied to the liquid crystal layer30. In other words, the second transparent voltage VA2is applied to the liquid crystal layer30.

However, the source line voltage Vsig in the transparent drive is not limited to the example shown inFIG.9. For example, the source line voltage Vsig may be higher than 0V and less than 8V (0V<Vsig<8V) in a period in which the common voltage Vcom becomes 0V. The source line voltage Vsig may be higher than 8V and less than 16V (8V<Vsig<16V) in a period in which the common voltage Vcom becomes 16V. In either of the cases, according to the transparent drive, an absolute value of the difference between the source line voltage Vsig and the common voltage Vcom is less than 8V and the parallelism of the light transmitted through the liquid crystal layer30is increased. In other words, the second transparent voltage VA2is not limited to 0V, but an absolute value of the second transparent voltage VA2may be less than 8V.

Incidentally, in the transparent drive, the voltage to be applied to the liquid crystal layer30may be less than the lower limit (for example, 8V) of the gradation, and the source line voltage Vsig may not completely match the common voltage Vcom. As described above, the degree of scattering in a case where the degree of scattering of the light made incident on the liquid crystal layer30is the highest when the scattering voltage VB is applied to the liquid crystal layer30is assumed to be 100%. It is desirable that, for example, the second transparent voltage VA2is a voltage with the degree of scattering in a range lower than 10%.

FIG.10is a chart showing another example of the common voltage Vcom and the source line voltage Vsig in the transparent drive. The waveform of the source line voltage Vsig is represented by a solid line, and the waveform of the common voltage Vcom is represented by a two-dot-chain line.

As shown inFIG.10, in this example, the polarity inversion of the common voltage Vcom and the source line voltage Vsig is stopped in the transparent drive. Furthermore, the common voltage Vcom and the source line voltage Vsig match at 8V (above-described reference voltage Vsig-c). Incidentally, the common voltage Vcom and the source line voltage Vsig may match at a voltage other than the reference voltage Vsig-c, such as 0V. In addition, it is desirable that the second transparent voltage VA2is a voltage with the degree of scattering in a range lower than 10%, similarly to the case shown inFIG.9.

The one-line inversion drive scheme has been described above as the example of the transparent drive, but the same transparent drive can also be applied to a line-inversion drive scheme of two or more lines and a frame inversion drive scheme.

Next, a configuration example of the timing controller TC will be described. A drive scheme in which one frame period includes a plurality of sub-frame (field) periods will be applied to the display device DSP. Such a drive scheme is referred to as, for example, a field sequential system. Red, green, and blue images are displayed in the respective sub-frame periods. The images of the colors displayed in time division are mixed and visually recognized as multi-color display image by the user.

FIG.11is a diagram showing a configuration example of the timing controller TC shown inFIG.3.

As shown inFIG.11, the timing controller TC comprises a timing generation unit50, a frame memory51, line memories52R,52G, and52B, a data conversion unit53, a light source control unit54, a detection unit55serving as an address detection unit, and the like.

The frame memory51stores image data for one frame input from the outside. The line memories52R,52G, and52B store sub-frame data of red, green, and blue colors, respectively. The sub-frame data represent red, green, and blue images (for example, gradation values of the pixels PX) which the pixels PX are urged to display in time division. The sub-frame data of each of the colors stored in the line memories52R,52G, and52B corresponds to a previous frame of the image data stored in the frame memory51.

The data conversion unit53processes the sub-frame data of the colors stored in the line memories52R,52G, and52B by various types of data conversion processing such as gamma correction, generates a video signal, and outputs the video signal to the above-described source driver SD. Incidentally, the timing controller TC may be configured to transmit RGB data to the data conversion unit53by allocating the RGB data in the frame memory51. In this case, the timing controller TC can also be constituted without the line memories52R,52G, and52B.

The light source control unit54outputs the light source control signal to the above-described light source driver LSD. The light source driver LSD drives the light emitting elements LSR, LSG, and LSB in accordance with the light source control signal. The light emitting elements LSR, LSG, and LSB can be driven under, for example, pulse width modulation (PWM) control. In other words, the light source driver LSD can adjust the luminance of each of the light emitting elements LSR, LSG, and LSB with the duty ratios of the signals output to the light emitting elements LSR, LSG, and LSB.

The timing generation unit50controls the operation timing of the frame memory51, the line memories52R,52G, and52B, the data conversion unit53, and the light source control unit54, in synchronization with a vertical synchronization signal Vsync and a horizontal synchronization signal Hsync that are input from the outside. In addition, the timing generation unit50controls the source driver SD by outputting a source driver control signal, controls the gate driver GD by outputting a gate driver control signal, and outputs a Vcom control signal.

The detection unit55is configured, when image data for one frame input from the outside includes data of an image, to detect an address of the data of the image. Examples of the image include a character displayed in a part of the display area DA. Examples of the character include a symbol including a letter, a figure, an icon, and the like. In addition, the case where data of the character is included in the image data means a case where data other than 0 is included in at least one piece of all bits of digital data. Address information of the data of the image is supplied to the data conversion unit53. For this reason, when the image data is included in data of images input from the outside, the timing controller TC adjusts the degree of scattering (transparency) of an area other than the area where the images are displayed, and can generate the processed video signal and output the processed video signal to the source driver SD. When generating the processed video signal, the timing controller TC can perform calculation using the data conversion unit53and perform the generation using the data stored in a table56of the timing controller TC.

Next, a process of adhering the display panel PNL to the cover panel CO1in the method of manufacturing the display device DSP of the present embodiment will be described.FIG.12is an exploded perspective view showing the display panel PNL and the cover panel CO1of the display device DSP, illustrating a state in which the display panel PNL is to be adhered to the cover panel CO1.

As shown inFIG.12, the cover panel CO1is prepared. The first transparent substrate ME1of the cover panel CO1is curved. The first transparent substrate ME1is curved such that the second main surface Sa2side is convex. However, the first transparent substrate ME1may be curved such that the first main surface Sa1side is convex.

The first transparent substrate ME1further has a side surface Sb3and a side surface Sb4. Each of the side surfaces Sb1and Sb2extends straight. More specifically, the long side SI1of the side surface Sb1and the long side SI2of the side surface Sb2are straight. In contrast, each of the side surfaces Sb3and Sb4extends to be curved. More specifically, the long side SI3of the side surface Sb3and the long side SI4of the side surface Sb4are curved. Based on the above, the side surface Sb1opposed to the light emitting element LS is a non-curved surface. The cross-section of the first transparent substrate ME1on the Y-Z plane is not curved, but the cross-section of the first transparent substrate ME1on the X-Z plane is curved.

Then, the display panel PNL is adhered to the cover panel CO1. At this time, the first adhesive sheet AD1is adhered to one of the display panel PNL and the cover panel CO1. In this example, the first adhesive sheet AD1is adhered to the display panel PNL. After that, the display panel PNL and the cover panel CO1are opposed to each other. The display panel PNL is not curved before the display panel PNL is adhered to the cover panel CO1. After that, the display panel PNL is pressed against the cover panel CO1, and the display panel PNL is adhered to the cover panel CO1. The display panel PNL is thereby curved according to the cover panel CO1.

FIG.13is a cross-sectional view showing the display device DSP of the embodiment.FIG.13shows only the first basement10and the second basement20of the display panel PNL.

As shown inFIG.13, the cover panel CO1(first transparent substrate ME1), the first adhesive sheet AD1, and the display panel PNL are curved such that the second main surface Sa2side is convex, in the cross-section of the display device DSP on a virtual plane parallel to the Y-Z plane.

The light emitting element LS is composed of, for example, a light emitting diode. However, the light emitting element LS may be a laser or a laser diode. In such a case, it is desirable to provide a lens between the light emitting element LS and the side surfaces Sb1and Sc1, spread the light emitted by the light emitting element LS in the X-Y plane direction, and make the light incident on the side surfaces Sb1and Sc1.

The light emitting element LS can emit light onto the side surface Sb1of the first transparent substrate ME1having the thickness Ta. Since the size of the light emitting element LS opposed to the side surface Sb1can be increased, the luminance level of the light emitted by the light emitting element LS can be increased in proportion to the above-mentioned size. Therefore, the user can visually recognize the display image of the display device DSP desirably.

In the present embodiment, the side surfaces Sb1and Sc1are located on the same plane. In addition, the light emitting element LS is opposed to not only the side surface Sb1of the first transparent substrate ME1but also the side surface Sc1of the second basement20. The size of the light emitting element LS can be further increased, and the luminance level of the light emitted by the light emitting element LS can be further increased. Therefore, the user can visually recognize the display image of the display device DSP further desirably.

According to the display device DSP of the first embodiment configured as described above, the display device DSP comprises the first transparent substrate ME1, the display panel PNL, the first adhesive sheet AD1, and the first light source unit LU1. When the display panel PNL is flexible, the thicknesses Tb1and Tb2become smaller. For example, if light is emitted only on the side surface Sc1of the second basement20, the amount of light may be insufficient and the user can hardly visually recognize the image (character) displayed on the display device DSP.

Therefore, the first light source unit LU1can emit light at a high luminance level to the first transparent substrate ME1and the like. The user can easily visually recognize the image (character) displayed on the display device DSP. Therefore, the display device DSP capable of increasing the display quality can be obtained. In addition to the above, various suitable advantages can be obtained from the present embodiment.

Modified Example 1 of First Embodiment

Next, modified example 1 of the first embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the first embodiment except for the configuration described in modified example 1.FIG.14is a cross-sectional view showing the display device DSP of modified example 1.

As shown inFIG.14, the display device DSP further comprises a second light source unit LU2. The second light source unit LU2comprises a light emitting element LS and the like. The side surface Sb2of the first transparent substrate ME1is a second light incident surface on a side opposite to the side surface (first light incident surface) Sb1. The second basement20has the side surface Sc2on a side opposite to the side surface Sc1.

The light emitting element LS of the second light source unit LU2is composed of a light emitting diode. The light emitting element LS has a light emitting portion (light emitting surface) that is opposed to the side surface Sb2to emit light to the side surface Sb2. In modified example 1, the light emitting element LS is also opposed to the side surface Sc2of the second basement20. The illumination light emitted from the light emitting element LS is also made incident on the side surface Sc2.

The light emitting element LS of the second light source unit LU2can emit the light to the side surface Sb2of the first transparent substrate ME1. Since the size of the light emitting element LS opposed to the side surface Sb2can be increased, the luminance level of the light emitted by the light emitting element LS can be increased in proportion to the above-mentioned size. Therefore, the user can visually recognize the display image of the display device DSP desirably.

In modified example 1, the side surfaces Sb2and Sc2are located on the same plane. In addition, the light emitting element LS of the second light source unit LU2is opposed to not only the side surface Sb2of the first transparent substrate ME1but also the side surface Sc2of the second basement20. The size of the light emitting element LS of the second light source unit LU2can be further increased, and the luminance level of the light emitted by the light emitting element LS of the second light source unit LU2can be further increased. Therefore, the user can visually recognize the display image of the display device DSP further desirably.

In modified example 1, the same advantages as the above-described first embodiment can also be obtained. Furthermore, in modified example 1, light can be emitted to both side surfaces of the first transparent substrate ME1. Therefore, the user can visually recognize the display image of the display device DSP further desirably.

Modified Example 2 of First Embodiment

Next, modified example 2 of the first embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the first embodiment except for the configuration described in modified example 2.FIG.15is a cross-sectional view showing the display device DSP of modified example 2.

As shown inFIG.15, the side surface Sb1of the first transparent substrate ME1and the side surface Sc1of the second basement20are not located on the same plane. In modified example 2, side surface Sb1is located more closely to the display area DA side than the side surface Sc1. The light emitting element LS of the first light source unit LU1is opposed to the side surface Sb1of the first transparent substrate ME1, but is not opposed to the side surface Sc1of the second basement20.

The light emitting element LS of the first light source unit LU1can emit light to the side surface Sb1of the first transparent substrate ME1. The luminance level of the light emitted by the light emitting element LS can be made higher as compared to the case where light is emitted to the only side surface Sc1of the second basement20. Therefore, the user can visually recognize the display image of the display device DSP desirably. In modified example 2, the same advantages as the above-described first embodiment can also be obtained.

Modified Example 3 of First Embodiment

Next, modified example 3 of the first embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the first embodiment except for the configuration described in modified example 3.FIG.16is a cross-sectional view showing the display device DSP of modified example 3.

As shown inFIG.16, the display device DSP comprises a cover panel CO2. The cover panel CO2comprises a second transparent substrate ME2. The second transparent substrate ME2is a cover glass and is formed of glass. The second transparent substrate ME2is a non-flexible substrate. The second transparent substrate ME2overlaps with at least the entire display area DA.

The second transparent substrate ME2has a third main surface Sa3, a fourth main surface Sa4, a side surface Sd1, and a side surface Sd2. The third main surface Sa3is opposed to the display panel PNL. The fourth main surface Sa4is located on a side opposite to the third main surface Sa3. The side surface Sd1is located between the third main surface Sa3and the fourth main surface Sa4. The side surface Sd2is located between the third main surface Sa3and the fourth main surface Sa4and is located on a side opposite to the side surface Sd1. The side surface Sd2is a third light incident surface. In modified example 3, the side surfaces Sd1and Sd2are located in the non-display area NDA. The display panel PNL is sandwiched between the second transparent substrate ME2and the first transparent substrate ME1, and the second transparent substrate ME2is curved in accordance with the first transparent substrate ME1.

The second adhesive sheet AD2(also referred to as a second fixing member) is located between the second transparent substrate ME2and the display panel PNL, and adheres the display panel PNL to the second transparent substrate ME2. The second adhesive sheet AD2contacts and sticks to the second transparent substrate ME2on one side and contacts and sticks to the display panel PNL on the other side. The second adhesive sheet AD2overlaps with at least the entire display area DA. The second adhesive sheet AD2is formed of OCA, but may be formed of a material other than OCA.

The first basement10has a side surface Se1located more closely to the side surface Sd1side than the display area DA and a side surface Se2located more closely to the side surface Sd2side than the display area DA. In the first basement10, the side surface Se2is located on the side opposite to the side surface Se1.

The display device DSP comprises a second light source unit LU2. The second light source unit LU2is located in the non-display area NDA. The second light source unit LU2comprises a light emitting element LS and the like. The light emitting element LS of the second light source unit LU2is composed of a light emitting diode. The light emitting element LS has a light emitting portion (light emitting surface) that is opposed to the side surface Sd2to emit light to the side surface Sd2.

Illumination light emitted from the light emitting element LS is made incident on the side surface Sd2and propagates through the second transparent substrate ME2(cover panel CO2), the second adhesive sheet AD2, the display panel PNL, the first adhesive sheet AD1, and the first transparent substrate ME1(cover panel CO1). In modified example 3, the light emitting element LS of the second light source unit LU2is also opposed to the side surface Se2of the first basement10. Illumination light emitted from the light emitting element LS of the second light source unit LU2is also made incident on the side surface Se2.

Similarly to modified example 3, the display panel PNL is sandwiched between the first transparent substrate ME1and the second transparent substrate ME2. Not only the first transparent substrate ME1but also the second transparent substrate ME2can function as a light guide.

The light emitting element LS of the second light source unit LU2can emit light to the side surface Sd2of the second transparent substrate ME2. Since the size of the light emitting element LS opposed to the side surface Sd2can be increased, the luminance level of the light irradiated by the light emitting element LS can be increased in proportion to the above size.

In modified example 3, the side surfaces Sd2and Se2are located on the same plane. In addition, the light emitting element LS of the second light source unit LU2is opposed to not only the side surface Sd2of the second transparent substrate ME2but also the side surface Se2of the first basement10. The size of the light emitting element LS of the second light source unit LU2can be further increased, and the luminance level of the light emitted by the light emitting element LS of the second light source unit LU2can be further increased. Therefore, the user can visually recognize the display image of the display device DSP further desirably. In modified example 3, the same advantages as the above-described first embodiment can also be obtained.

Incidentally, in modified example 3, the side surfaces Sd2, Se2, Sc2, and Sb2are located on the same plane. Therefore, the light emitting element LS of the second light source unit LU2may be opposed to the side surface Sd2, the side surface Se2, the side surface Sc2, and the side surface Sb2. The size of the light emitting element LS of the second light source unit LU2can be further increased. In this case, the display device DSP may comprise a first light source unit LU1as needed.

Second Embodiment

Next, a second embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the first embodiment except for the configuration described in the second embodiment.FIG.17is a developed cross-sectional view showing the display device DSP of the second embodiment.FIG.18is a plan view showing a cover panel CO1and a first light source unit LU1of the second embodiment, developing the cover panel CO1. InFIG.18, a part with a dot pattern is an optical layer60. Incidentally, an actual first transparent substrate ME1, a display panel PNL, and the like are curved.

As shown inFIG.17, the display device DSP further comprises an optical layer60, which is a transparent layer. The optical layer60is located between the first transparent substrate ME1and the display panel PNL. The optical layer60is in contact with a first main surface Sa1of the first transparent substrate ME1. In the present embodiment, a cover panel CO1comprises the first transparent substrate ME1and the optical layer60.

As shown inFIG.17andFIG.18, the optical layer60is in contact with the entire first main surface Sa1. In plan view, the optical layer60overlaps with the entire display area DA and the entire non-display area NDA. The optical layer60is formed of an organic material such as siloxane-based resin or fluorine-based resin. The refractive index of the optical layer60is substantially 1.0 to 1.4.

Each of a second basement20and the first transparent substrate ME1of the display panel PNL is formed of glass. The refractive index of each of the second basement20and the first transparent substrate ME1is 1.51. For this reason, the refractive index of the optical layer60is lower than that of the second basement20. Furthermore, the refractive index of the optical layer60is lower than the refractive index of the first transparent substrate ME1.

In the display device DSP of the second embodiment configured as described above, the same advantages as those of the first embodiment can be obtained, and the display device DSP capable of improving the display quality can be obtained. The first transparent substrate ME1and the optical layer60can desirably propagate light made incident from the side surface Sb1to the side surface Sb2side inside the first transparent substrate ME1. By providing the optical layer60in the display device DSP, light components that pass from the first transparent substrate ME1to an upper surface20T of the second basement20can be suppressed. Therefore, the situation in which the brightness of the image displayed by the display device DSP is different on the side surface Sb1side and the side surface Sb2side can be suppressed. The optical layer60may be formed as a solid film or as a dotted film. Furthermore, the light emitted by the light emitting elements LS is desirably made more incident on the side surface Sb1and less incident on the side surface Sb2. The light emitted by the light emitting elements LS may be made incident on an entire side surface Sb1or a substantially entire side surface Sb1. The light emitting elements LS or the light emitting portions of the light emitting elements LS may be configured such that the area opposed to the side surface Sb1is larger than the area opposed to the side surface Sb2. The light emitting elements LS or the light emitting portions of the light emitting elements LS may be configured to be opposed to the side surface Sb1and not to be opposed to the side surface Sb2.

Unlike the above-described second embodiment, the first adhesive sheet AD1may have the function of the optical layer60. In this case, the display device DSP is formed without the optical layer60. When the first adhesive sheet AD1has the function of the optical layer60, the refractive index of the first adhesive sheet AD1is 1.41 to 1.48. For this reason, the refractive index of the first adhesive sheet AD1is lower than that of the second basement20. Furthermore, the refractive index of the first adhesive sheet AD1is lower than that of the first transparent substrate ME1.

Modified Example 1 of Second Embodiment

Next, modified example 1 of the second embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the second embodiment except for the configuration described in modified example 1.FIG.19is a plan view showing the cover panel CO1and the first light source unit LU1of modified example 1, developing the cover panel CO1. InFIG.19, a part with a dot pattern is the optical layer60.

As shown inFIG.19, the first main surface Sa1of the first transparent substrate ME1has one or more contact areas CA, and a non-contact area NCA other than the one or more contact areas CA. The optical layer60is in contact with the entire one or more contact areas CA. The optical layer60is in contact with a part of the first main surface Sa1. The proportion of the area of the one or more contact areas CA on the first main surface Sa1is larger toward the side surface Sb1. In other words, the optical layer60is patterned as represented in the dot pattern.

The optical layer60comprises a plurality of band portions61and a frame portion62surrounding the plurality of band portions61. The frame portion62is located in the non-display area NDA. The band portions61and the frame portion62are formed integrally. Each of the band portions61includes a first end portion611on the side opposite to the light emitting element LS, a second end portion612on the side opposite to the first end portion611, a first edge613, and a second edge614. A width of the first end portion611is greater than a width of the second end portion612in the first direction X.

The first edge613and the second edge614extend in a direction different from the first direction X and the second direction Y, at positions between the first end portion611and the second end portion612. A direction that intersects the second direction Y clockwise at an acute angle is defined as a direction D1, and a direction that intersects the second direction Y counterclockwise at an acute angle is defined as a direction D2. The first edge613extends in the direction D1, and the second edge614extends in the direction D2. In this example, each of the band portions61is formed in a triangular shape, and both the first edge613and the second edge614extend straight. However, the shape of the band portion61is not limited to a triangular shape. For example, each of the first edge613and the second edge614may be formed in a curved shape.

In modified example 1, the same advantages as the above-described second embodiment can also be obtained. Furthermore, in the display area DA, the proportion of the area in which the optical layer60is formed is larger toward the side surface Sb1. As the distance to the side surface Sb1is shorter, it is more difficult for light to escape from the first transparent substrate ME1to the upper surface20T of the second basement20. In contrast, as the distance to the side surface Sb2is shorter, it is easier for light to escape from the first transparent substrate ME1to the upper surface20T of the second basement20. For this reason, the situation in which the brightness of the image displayed by the display device DSP is different on the side surface Sb1side and the side surface Sb2side can be further suppressed.

The first edge613and the second edge614are not parallel to the first direction X. Therefore, scattering of light at the first edge613and the second edge614can be suppressed.

Modified Example 2 of Second Embodiment

Next, modified example 2 of the second embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of modified example 1 of the second embodiment except for the configuration described in modified example 2.FIG.20is a plan view showing the cover panel CO1, the first light source unit LU1, and the second light source unit LU2of modified example 2, developing the cover panel CO1. InFIG.20, a part with a dot pattern is the optical layer60.

As shown inFIG.20, the display device DSP comprises a second light source unit LU2. The first light source unit LU1and the second light source unit LU2can emit light to the first transparent substrate ME1from both sides. Each of the band portions61includes a middle portion615in the second direction Y. The width of each of the band portions61is reduced at the middle portion615. The width of the first end portion611is greater than the width of the middle portion615, and the width of the second end portion612is greater than the width of the middle portion615, in the first direction X. The width of the band portion61is reduced gradually from the first end portion611toward the middle portion615. In addition, the width of the band portion61is reduced gradually from the second end portion612toward the middle portion615.

In modified example 2, the same advantages as the above-described modified example 1 of the second embodiment can also be obtained. Furthermore, by reducing the width of the band portion61at the middle portion615, more light can reach the center of the display area DA of the display panel PNL when the light is emitted on both sides of the first transparent substrate ME1. Therefore, the reduction in the luminance level in the center of the display device DSP can be suppressed.

Third Embodiment

Next, a third embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the first embodiment except for the configuration described in the third embodiment.FIG.21is a developed cross-sectional view showing the display device DSP of the third embodiment.FIG.22is a plan view showing a cover panel CO1, a first light source unit LU1, and an optical member70of the display device DSP of the third embodiment, developing the cover panel CO1. Incidentally, an actual first transparent substrate ME1, a display panel PNL, and the like are curved.FIG.23is a perspective view showing a part of the optical member70of the third embodiment.

As shown inFIG.21andFIG.22, the display device DSP further comprises the optical member70. The optical member70extends in the first direction X and is located between the side surface Sb1of the first transparent substrate ME1and the first light source unit LU1(light emitting elements LS). The light emitting elements LS emit light toward the optical member70. The optical member70has a function of focusing the light made incident from the first light source unit LU1and transmitting the light to the side surface Sb1side. The optical member70can increase the components of the light traveling in a direction parallel to the second direction Y and transmit the light to the side surface Sb1, in the Y-Z plane. The optical member70can also limit the light in the thickness direction (third direction Z). For example, the light made incident on the first transparent substrate ME1can hardly leak outward from the second main surface Sa2. Therefore, the light can desirably propagate to the side surface Sb2side inside the first transparent substrate ME1.

In the present embodiment, the optical member70is also located between the side surface Sc1of the second basement20and the first light source unit LU1(light emitting elements LS). The optical member70can also focus the light made incident from the first light source unit LU1and transmit the light to the side surface Sc1side.

As shown inFIG.23, the optical member70is a microlens array including a plurality of arrayed microlenses71and a plate-shaped transparent layer72. The plurality of microlenses71and the transparent layer72are formed integrally. Each of the microlenses71is raised so as to be convex on the side surface Sb1side or the side surface Sc1side. In plan view in which the optical member70is viewed from the side surface Sb1side, the shape of the microlens71is a quadrangular shape. In plan view, however, the shape of the microlens71may be a polygon other than a quadrangle, such as a hexagon, or may be a circle.

In the display device DSP of the third embodiment configured as described above, the same advantages as those of the first embodiment can be obtained, and the display device DSP capable of improving the display quality can be obtained. The components of the light made incident perpendicularly on the side surfaces Sb1and Sc1can be increased by providing the optical layer70. The light emitted by the light emitting elements LS can be efficiently input (transmitted) to the inside of the first transparent substrate ME1and the inside of the second basement20. Therefore, the user can visually recognize the display image of the display device DSP further desirably. Alternatively, the power consumption of the light source unit LU1can be reduced. Incidentally, the optical member70may be a lenticular lens.

Fourth Embodiment

Next, a fourth embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the first embodiment except for the configuration described in the fourth embodiment.FIG.24is a developed cross-sectional view showing the display device DSP of the fourth embodiment.FIG.25is a plan view showing a cover panel CO1and a first light source unit LU1of the fourth embodiment, developing the cover panel CO1. Incidentally, an actual first transparent substrate ME1, a display panel PNL, and the like are curved.

As shown inFIG.24andFIG.25, the display device DSP further comprises a first light reflective layer LR1and a second light reflective layer LR2. In the present embodiment, the cover panel CO1comprises the first transparent substrate ME1, the first light reflective layer LR1, and the second light reflective layer LR2. A first main surface Sa1of the first transparent substrate ME1has a first reflective area RA1and a second reflective area RA2located more closely to the side surface Sb1side than the first reflective area RA1. A second main surface Sa2of the transparent substrate ME1has a third reflective area RA3and a fourth reflective area RA4located more closely to the side surface Sb1side than the third reflective area RA3. Each of the second reflective area RA2and the fourth reflective area RA4does not overlap with the display area DA.

The first light reflective layer LR1is opposed to the second reflective area RA2of the first main surface Sa1and is not opposed to the first reflective area RA1. The first light reflective layer LR1can reflect light that could leak from the second reflective area RA2to the outside of the first transparent substrate ME1and return the light to the inside of the first transparent substrate ME1. The second light reflective layer LR2is opposed to the fourth reflective area RA4of the second main surface Sa2and is not opposed to the third reflective area RA3. The second light reflective layer LR2can reflect light that could leak from the fourth reflective area RA4to the outside of the first transparent substrate ME1and return the light to the inside of the first transparent substrate ME1.

In the display device DSP of the fourth embodiment configured as described above, the same advantages as those of the first embodiment can be obtained, and the display device DSP capable of improving the display quality can be obtained. The first light reflective layer LR1and the second light reflective layer LR2can suppress the generation of light that does not propagate inside the first transparent substrate ME1. Therefore, the user can visually recognize the display image of the display device DSP further desirably. Alternatively, the power consumption of the light source unit LU1can be reduced.

Fifth Embodiment

Next, a fifth embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the first embodiment except for the configuration described in the fifth embodiment.FIG.26is a cross-sectional view showing the display device DSP of the fifth embodiment.

As shown inFIG.26, an angle θ1between the first main surface Sa1and the side surface Sb1is an angle other than 90 degrees. The side surface Sb1and the angle θ1are adjusted by performing polishing (mechanical polishing) on the first transparent substrate ME1. The light emitting element LS (light emitting portion EM) is opposite to the side surface Sb1.

In the present embodiment, the angle θ1is an acute angle, but may be an obtuse angle. In the present embodiment, however, the angle θ1is desirably an acute angle. This is because the first transparent substrate ME1is curved such that the second main surface Sa2side is convex and because the light made incident on the first transparent substrate ME1is difficult to leak outward from the second main surface Sa2.

In the display device DSP of the fifth embodiment configured as described above, the same advantages as those of the first embodiment can be obtained, and the display device DSP capable of improving the display quality can be obtained. Since the angle θ1is an angle other than 90 degrees, the light input efficiency to the display area DA of the display panel PNL can be increased. Therefore, the user can visually recognize the display image of the display device DSP further desirably. Alternatively, the power consumption of the light source unit LU1can be reduced.

Sixth Embodiment

Next, a sixth embodiment will be described. The display device DSP is configured in the same manner as the display device DSP of the first embodiment except for the configuration described in the sixth embodiment.FIG.27is a plan view showing a cover panel CO1and a first light source unit LU1of the display device DSP of the sixth embodiment, developing the cover panel CO1.FIG.28is a cross-sectional view showing the cover panel CO1and the light emitting element LS along line XXVIII-XXVIII inFIG.27. Incidentally, an actual first transparent substrate ME1, and the like are curved.

As shown inFIG.27andFIG.28, the side surface Sb1that is a first light incident surface, is a surface obtained by drawing a scribe line on the glass substrate and breaking the glass substrate. The side surface Sb1is a flat surface. The corners of the first transparent substrate ME1on the side surface Sb1side are not chamfered. In addition, the side surface Sb1is not polished. Since the light emitting element LS emits light to the side surface Sb1, the first transparent substrate ME1can desirably propagate the light inside. For example, since the light made incident on the second main surface Sa2satisfies the condition for total reflection, the light made incident on the first transparent substrate ME1can hardly leak outward from the second main surface Sa2.

Incidentally, if the corners of the side surface Sb1of the first transparent substrate ME1are chamfered or the side surface Sb1is polished, the first transparent substrate ME1can hardly propagate the light inside desirably. For example, since the light made incident on the second main surface Sa2includes components of the light made incident on the second main surface Sa2at an angle close to 90 degrees, the light made incident on the first transparent substrate ME1can easily leak outward from the second main surface Sa2.

In contrast, the side surfaces Sb2, Sb3, and Sb4are different from the side surface Sb1. The configurations of the respective side surfaces Sb2, Sb3, and Sb4are the same as each other. In this example, the side surface Sb2represents the side surfaces Sb2, Sb3, and Sb4.

To obtain the side surface Sb2, first, scribe lines are drawn on the glass substrate and the glass substrate is broken. After that, the corners of the first transparent substrate ME1on the side surface Sb2side are chamfered. In addition, the side surface Sb2is polished. Since unevenness is formed on the side surface Sb2, the side surface Sb2is not flatter than the side surface Sb1.

In the display device DSP of the sixth embodiment configured as described above, the same advantages as those of the first embodiment can be obtained, and the display device DSP capable of improving the display quality can be obtained. Since the side surface Sb1that is the first light incident surface is a flat surface, the light input efficiency to the display area DA of the display panel PNL can be increased. Therefore, the user can visually recognize the display image of the display device DSP further desirably. Alternatively, the power consumption of the light source unit LU1can be reduced.

The side surfaces Sb2, Sb3, and Sb4of the first transparent substrate ME1are chamfered and polished. Therefore, the occurrence of chipping due to handling during manufacturing the cover panel CO1or assembling a module using the cover panel CO1can be suppressed or prevented.

The first, second, and third colors are not limited to red, blue, and green colors, respectively. In addition, the light source unit LU may comprise the light emitting elements LS of two or less colors or the light emitting elements LS of four or more colors. Alternatively, the light source unit LU may comprise a light emitting element LS of white color. The number of line memories, the number of items of the sub-frame data, and the number of the sub-frame periods may be increased or reduced in accordance with the number of types (number of colors) of the light emitting elements LS.

The liquid crystal layer30may use normal polymer dispersed liquid crystal. The liquid crystal layer30maintains the parallelism of the light made incident when the applied voltage is high or scatters the incident light when the applied voltage is low.

Each of the first basement10and the second basement20of the display panel PNL may be formed of resin. In this case, each of the first basement10and the second basement20is desirably formed of an amorphous resin. One of examples of the amorphous resin is a cyclo-olefin polymer (COP). By forming the first basement10and the second basement20of amorphous resin, scattering of light inside each of the first basement10and the second basement20can be suppressed and the light can be guided desirably.

Incidentally, each of the first basement10and the second basement20may be formed of a crystalline resin. One of examples of a crystalline resin is polyethylene terephthalate (PET).