Indication device

Abstract

To improve the performance of the device. [Solution] The light guide plate 30 of the display device includes a side surface (first side surface) 30s1 facing the light source and extending along the X direction, a second side surface connected to one end of the first side surface and forming a curved surface, and a third side surface connected to the other end of the second side surface and forming a curved surface. The side surface 30s1 includes a first region, a region (second region) R2 located between the first region and the second side surface and connected to the second side surface, and a third region located between the first region and the third side surface and connected to the third side surface. Each of region R2 and the third region is provided with a plurality of protrusions 33 that can change the direction of light propagation.

Description

Technical Field

[0001] The present invention relates to a display device.

Background Art

[0002] As a display device, there is a display device including a light-emitting module in which red, green, and blue light-emitting elements are each packaged, and a light guide body provided at a position facing the light-emitting point of the light-emitting module (see Japanese Unexamined Patent Application Publication No. 2021-33043 (Patent Document 1)).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor of the present application is developing a transparent display device that allows an observer to recognize by overlapping a display image and a background. In the case of a display device, generally, the planar shape is a rectangle, but for example, from the viewpoint of designability and the like, there is a demand for a display panel having a planar shape other than a rectangle.

[0005] However, it has been found that in the case of a display panel having a planar shape other than a rectangle, the density of light incident on the light guide plate does not become constant, and the display quality may deteriorate.

Means for Solving the Problems

[0006] A display device according to one aspect of the present invention includes a first substrate having a first front surface and a first back surface opposite to the first front surface; a liquid crystal layer disposed on the first front surface of the first substrate; a light guide plate having a second back surface facing the first front surface via the liquid crystal layer and a second front surface opposite to the second back surface; a display area located in a position overlapping with a portion of the light guide plate; and a light source unit including a plurality of light-emitting elements. The light guide plate includes a first side surface facing the light source unit and extending along a first direction; a second side surface connected to one end of the first side surface and forming a curved surface; and a third side surface connected to the other end of the second side surface and forming a curved surface. The first side surface includes a first region; a second region located between the first region and the second side surface and connected to the second side surface; and a third region located between the first region and the third side surface and connected to the third side surface. Each of the second and third regions is provided with a plurality of protrusions that can change the direction of light propagation. [Brief explanation of the drawing]

[0007] [Figure 1] This is an explanatory diagram showing the positional relationship when a viewer on one side of a transparent display panel device views the background on the opposite side through the transparent display panel device. [Figure 2] This is an explanatory diagram showing an example of a background visible through a transparent display panel device. [Figure 3] Figure 1 is a plan view showing an example of a transparent display panel. [Figure 4] This is a cross-sectional view along line AA in Figure 3. [Figure 5] Figure 3 is a circuit block diagram showing an example of the circuitry included in the display panel. [Figure 6] This is a plan view schematically showing the path of light introduced into the light guide plate in a display panel, which is an example of a study for Figure 3. [Figure 7] This is an enlarged plan view showing a magnified view of the area around one end of the side of the light guide plate shown in Figure 3, which faces the light source. [Figure 8]This is an enlarged plan view showing the area around the other end of the side of the light guide plate shown in Figure 3 that faces the light source. [Figure 9] This is a perspective view showing an example of multiple protrusions formed on a light guide plate. [Figure 10] This is a perspective view showing an example of multiple protrusions formed on a light guide plate. [Figure 11] This is an enlarged cross-sectional view along line BB in Figure 9 or line CC in Figure 10. [Figure 12] This is a perspective view showing a modified example of multiple protrusions formed on a light guide plate. [Figure 13] This is a perspective view showing a modified example of multiple protrusions formed on a light guide plate. [Figure 14] This is an enlarged cross-sectional view along line DD in Figure 12, or line EE in Figure 13. [Figure 15] This is an enlarged cross-sectional view showing modified examples of the multiple protrusions shown in Figure 11. [Figure 16] Figure 12 is a perspective view showing other variations of the multiple protrusions shown. [Figure 17] This is an enlarged cross-sectional view along the FF line in Figure 16. [Figure 18] This is an enlarged cross-sectional view showing an example of the shape of the convex portion in the region opposite to the region shown in Figure 17. [Figure 19] This is an enlarged cross-sectional view showing other variations of Figure 11. [Figure 20] This is an enlarged cross-sectional view showing other variations of Figure 11. [Figure 21] This is an enlarged cross-sectional view showing other variations of Figure 11. [Modes for carrying out the invention]

[0008] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Note that the disclosure is merely an example, and for those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the invention, they are naturally included in the scope of the present invention. In addition, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but this is merely an example and does not limit the interpretation of the present invention. Also, in this specification and each figure, elements that are the same or related to those previously described with respect to the existing figures may be assigned the same or related reference numerals, and detailed descriptions may be omitted as appropriate.

[0009] In the following embodiments, as an example of a display panel used in combination with a glass plate, a liquid crystal display device that displays an image by utilizing the scattering of visible light by liquid crystal molecules will be taken up and described.

[0010] Also, a liquid crystal display device is a device that forms a display image by changing the orientation of molecules contained in a liquid crystal layer, and requires a light source. In the embodiments described below, the light source is provided separately from the display panel. Therefore, in the following, the display panel and the light source module that supplies visible light to the display panel will be described separately.

[0011] <Transparent display panel> First, the characteristics of a so-called transparent display panel will be described. FIG. 1 is an explanatory diagram showing the positional relationship when a viewer on one side of a transparent display panel views a background on the opposite side through the transparent display panel. FIG. 2 is an explanatory diagram showing an example of the background viewed through the transparent display panel. Note that, as shown in FIG. 3 to be described later, the display panel P2 of the present embodiment does not have a rectangular planar shape, but in FIGS. 1 and 2, as an example of the transparent display panel, a display panel P1 with a rectangular planar shape will be used for explanation.

[0012] The display panel P1 shown in Figures 1 and 2 is a transparent display panel. As shown in Figure 1, when an observer 100 looks from one side of the display panel P1 to the other, the background 101 is visible through the display panel P1. As shown in Figure 2, the display panel P1 has a display area DA and a peripheral area PFA located outside the display area DA. The display panel P1 can display an image 102 in the display area DA. In Figure 2, text is shown as an example of image 102. However, image 102 is not limited to text, and may be a graphic or a photograph. Also, image 102 is not limited to a still image, and may be a moving image. The observer 100 (see Figure 1) can simultaneously view both the image 102 and the background 101 displayed in the display area DA of the display panel P1.

[0013] When both the display area DA and the surrounding area PFA shown in Figure 2 transmit light, the entire background 101 can be viewed without discomfort. On the other hand, if the surrounding area PFA has light-blocking properties that do not transmit light, a portion of the background 101 viewed through the display panel P1 is blocked by the surrounding area PFA, which may cause discomfort to the observer 100. Thus, in the case of a transparent display panel P1, it is preferable that both the display area DA and the surrounding area PFA have visible light transmittance. Furthermore, from the viewpoint of viewing the background 101 without discomfort, it is particularly preferable that the visible light transmission characteristics of the display area DA and the surrounding area PFA are similar.

[0014] Figure 3 is a plan view showing an example of a transparent display panel according to this embodiment. In Figure 3, the boundary between the display area DA and the peripheral area PFA is shown by a dashed line. In Figure 3, a portion of the signal wiring (specifically, the gate line GL and source line SL) that transmits signals for driving the liquid crystal, which is part of the circuitry of the display panel P2, is schematically shown by a dashed line. Figure 4 is an enlarged cross-sectional view along line AA shown in Figure 3. In the following drawings, including Figures 3 and 4, the direction along the thickness direction of the display panel P2 is referred to as the Z direction, the direction in which one side of the display panel P2 extends in the XY plane perpendicular to the Z direction is referred to as the X direction, and the direction intersecting the X direction is referred to as the Y direction.

[0015] Display panel P2, shown in Figure 3, differs from display panel P1, shown in Figures 1 and 2, in that its planar shape is not rectangular. However, display panel P2 is similar to display panel P1, shown in Figures 1 and 2, in that it is a transparent display panel.

[0016] As shown in Figure 4, the display panel P2 of this embodiment includes a substrate (array substrate) 10, a substrate (opposing substrate) 20, a light guide plate 30, a light source unit 50, and a drive circuit 70 (see Figure 4). The display panel P2 is a display device in which the emitted light L2 can be viewed from the outside without the need for a polarizing plate, as shown in Figure 4.

[0017] When configured as a display device DSP1 (see Figure 4), in addition to the various parts of the display panel P2 shown in Figure 3, it may also include, for example, a control circuit, a wiring board connected to the display panel P2, or a housing. In Figure 3, parts other than the display panel P2 are omitted from the illustration. In Figure 4, an example of wiring boards 11, 53 and a circuit (light source control unit 52 and control unit 90) connected to the display panel P2 is schematically shown. On the other hand, the housing is also omitted from the illustration in Figure 4.

[0018] The display panel P2 has a display area DA in which an image is formed according to an input signal supplied from an external source, and a peripheral area (frame area) PFA surrounding the display area DA. The display area DA is the effective area in which the display panel P2 displays an image when viewed from above. The substrate 10, the substrate 20, and the light guide plate 30 are each located in a position that overlaps with the display area DA when viewed from above.

[0019] Generally, the shape of the display area DA is often rectangular, as exemplified by the display panel P1 in Figure 2. In this embodiment, the display panel P2 has a non-rectangular display area DA in plan view. In the example shown in Figure 3, the display area DA has a shape in which a portion of an ellipse is missing. More specifically, the display area DA has a shape in which a portion of an ellipse containing a chord parallel to the major axis of the ellipse is missing.

[0020] As shown in Figure 4, the display panel P2 has substrates 10 and 20 bonded together facing each other via a liquid crystal layer LQL. Substrates 10 and 20 are arranged in the Z direction, which is the thickness direction of the display panel P2. In other words, substrates 10 and 20 face each other in the thickness direction (Z direction) of the display panel P2. Substrate 10 has a front surface (main surface, face) 10f that faces the liquid crystal layer LQL (and substrate 20). Substrate 20 also has a back surface (main surface, face) 20b that faces the front surface 10f (and liquid crystal layer LQL) of substrate 10. Substrate 10 is an array substrate in which multiple transistors (transistor elements) as switching elements (active elements) Tr (see Figure 5) are arranged in an array. Substrate 20 is a substrate provided on the display surface side. Substrate 20 can be referred to as a facing substrate in the sense that it is a substrate arranged facing the array substrate.

[0021] The display panel P2 further includes a light guide plate 30. The light guide plate 30 is a glass substrate made of, for example, glass. The light guide plate 30 has a back surface 30b facing the front surface 10f via a liquid crystal layer LQL (more specifically, via the liquid crystal layer LQL and the substrate 20), and a front surface 30f on the opposite side of the back surface 30b.

[0022] The light guide plate 30 has a side surface 30s1 facing the light source unit 50. The light guide plate 30 is bonded and fixed to the substrate 20 via an adhesive layer 32. At least in the display area DA, the gap between the light guide plate 30 and the substrate 20 is filled with the adhesive layer 32. In the example shown in Figure 4, the adhesive layer 32 is bonded to the entire back surface 30b of the light guide plate 30.

[0023] The adhesive layer 32 is made of a transparent resin material that can transmit visible light. Examples of visible light-transmitting adhesive layers 32 include transparent adhesive sheets called OCA (Optical Clear Adhesive) formed in sheet form, and OCR (Optical Clear Resin) which is made by curing a liquid transparent adhesive.

[0024] The liquid crystal layer LQL, which includes the liquid crystal LQ, is located between the front surface 10f of the substrate 10 and the back surface 20b of the substrate 20. The liquid crystal layer LQL is an optical modulation element. The display panel P2 has the function of modulating light passing through it by controlling the state of the electric field formed around the liquid crystal layer LQL via the switching element described above. The display area DA of the display panel P2 is superimposed on the liquid crystal layer LQL as shown in Figure 4.

[0025] Furthermore, substrates 10 and 20 are bonded together via a sealing portion (sealing material) SLM. The sealing portion SLM is positioned in the peripheral area PFA so as to surround the display area DA. Inside the sealing portion SLM is the liquid crystal layer LQL. The sealing portion SLM acts as a seal that encloses the liquid crystal between substrates 10 and 20. The sealing portion SLM also acts as an adhesive that bonds substrates 10 and 20 together.

[0026] In the example shown in Figure 4, a wiring board 53 for the light source is connected to the light source unit 50. The wiring board 53 is a flexible wiring board, also known as a flexible wiring board. The drive circuit 70 is mounted on the substrate 10. The optical path of the light L50 emitted from the light source unit 50 will be described later.

[0027] The light source unit 50 is fixed on the substrate 10. The light source unit 50 has a substrate 50S and a plurality of light-emitting elements 51 mounted on the substrate 50S. Each of the plurality of light-emitting elements 51 shown in Figure 3 is positioned opposite the side surface 30s1 of the light guide plate 30. This allows the light L50 emitted from the light-emitting elements 51 to be incident on the light guide plate 30 from the side surface 30s1. In the example shown in Figure 4, the substrate 50S of the light source unit 50 is connected to the wiring board 53. Each of the plurality of light-emitting elements 51 shown in Figure 3 is electrically connected to the wiring board 53 via the substrate 50S.

[0028] Each of the multiple light-emitting elements 51 shown in Figure 3 is, for example, a light-emitting diode. In the example shown in Figure 3, the multiple light-emitting elements 51 are arranged linearly along the X direction.

[0029] Next, the optical path of the light emitted from the light source unit 50 of the display panel P2 will be explained using Figure 4. As schematically shown by the dashed line in Figure 4, the light (light source light) L50 emitted from the light source unit 50 enters the liquid crystal layer LQL via the light guide plate 30. It propagates away from the side surface 30s1 while being reflected by the back surface 10b of the substrate 10 and the front surface 30f of the light guide plate 30. In the propagation path of the light L50, the back surface 10b of the substrate 10 and the front surface 30f of the light guide plate 30 are interfaces between a medium with a high refractive index and a medium with a low refractive index. Therefore, if the angle of incidence at which the light L50 enters the front surface 20f and the back surface 10b is greater than the critical angle, the light L50 undergoes total internal reflection at the front surface 20f and the back surface 10b.

[0030] Liquid crystal (LQ) is a polymer-dispersed liquid crystal (LC) (see Figure 5), containing a liquid crystalline polymer and liquid crystal molecules. The liquid crystalline polymer is formed in streaks, and the liquid crystal molecules are dispersed in the gaps between the polymer. Both the liquid crystalline polymer and the liquid crystal molecules exhibit optical anisotropy or refractive index anisotropy. The responsiveness of the liquid crystalline polymer to an electric field is lower than that of the liquid crystal molecules. The orientation direction of the liquid crystalline polymer hardly changes regardless of the presence or absence of an electric field.

[0031] On the other hand, the orientation direction of the liquid crystal molecules changes in response to the electric field when a voltage above a threshold is applied to the liquid crystal LQ. When no voltage is applied to the liquid crystal LQ, the optical axes of the liquid crystalline polymer and liquid crystal molecules are parallel to each other, and light L50 incident on the liquid crystal layer LQL is transmitted through with almost no scattering (transparent state). When a voltage is applied to the liquid crystal LQ, the optical axes of the liquid crystalline polymer and liquid crystal molecules intersect each other, and light L50 incident on the liquid crystal LQ is scattered within the liquid crystal layer LQL (scattered state). The display panel P2 controls the transparent state and the scattered state by controlling the orientation of the liquid crystal LQ in the propagation path of light L50. In the scattered state, light L50 is emitted as emitted light L2 by the liquid crystal LQ and exits the display panel P2 from the front 30f side.

[0032] Furthermore, background light incident from the back surface 10b passes through the substrate 10, the liquid crystal layer LQL, the substrate 20, and the light guide plate 30, and is emitted to the outside from the front surface 30f. The emitted light L2 and background light are visible to an observer on the front surface 30f side. The observer can perceive the emitted light L2 and the background light in combination. A display panel that allows an observer to perceive the displayed image and background in this way is called a transparent display panel.

[0033] Next, an example of the circuit configuration of the display panel P2 shown in Figure 3 will be described. Figure 5 is a circuit block diagram showing an example of the circuit of the display panel shown in Figure 3. The wiring path connected to the common electrode CE shown in Figure 5 is formed, for example, on the substrate 10 or substrate 20 shown in Figure 4. In Figure 5, the common potential wiring CML connected to the common electrode CE is shown as a dotted line. In the example shown in Figure 5, the light source control unit 52 is provided separately from the drive circuit 70.

[0034] In the example shown in Figure 4, the light source control unit 52 is connected to the wiring board 53. The light source control unit 52 may be formed directly on the wiring board 53, for example. Alternatively, the light source control unit 52 may be formed on an electronic component (not shown), and this electronic component may be mounted on the wiring board 53. Also in the example shown in Figure 4, the wiring board 11 is connected to the substrate 10. The control unit 90 is connected to the wiring board 11. The control unit 90 includes a control circuit 91 and a signal processing circuit 92 that supply control signals to the drive circuit 70. The wiring board 11 is a flexible wiring board, for example, called a flexible wiring board.

[0035] In the example shown in Figure 5, the drive circuit 70 comprises a pixel control circuit 71, a gate drive circuit 72, a source drive circuit 73, and a common potential drive circuit 74. The drive circuit 70 (particularly the gate drive circuit 72, the source drive circuit 73, and the common potential drive circuit 74) is a drive circuit that supplies signals for driving the liquid crystal layer LQL shown in Figure 4. In the example shown in Figure 5, the pixel control circuit 71 is included in the drive circuit 70, but there are various variations in the assignment of circuits included in the drive circuit 70 and the control unit 90. For example, the pixel control circuit 71 may be included in the control unit 90.

[0036] The control circuit 91 of the control unit 90 is a circuit that controls the display of the image. The signal processing circuit 92 includes an input signal analysis unit (input signal analysis circuit) 921, a storage unit (storage circuit) 922, and a signal adjustment unit 923. The input signal analysis unit 921 of the signal processing circuit 92 receives the input signal VS from the control circuit 91. The input signal analysis unit 921 performs analysis processing based on the input signal VS input from the outside and generates the input signal VCS. The input signal VCS is, for example, a signal that determines what gradation value to assign to each pixel of the display panel P2 (see Figure 3) based on the input signal VS.

[0037] The signal adjustment unit 923 generates an input signal VCSA from the input signal VCS input from the input signal analysis unit 921. The signal adjustment unit 923 sends the input signal VCSA to the pixel control circuit 71 via a wiring path such as the wiring board 11 (see Figure 4). In other words, the control circuit 91 of the control unit 90 supplies a control signal to the drive circuit 70 via the signal processing circuit 92. The signal adjustment unit 923 also sends a light source control signal LCSA to the light source control unit 52. The light source control signal LCSA is a signal that includes information about the amount of light from the light source unit 50, which is set according to the input grayscale value to the pixel.

[0038] The light source control unit 52 outputs signals to the light source unit 50 to drive each of the multiple light-emitting elements 51 provided by the light source unit 50 via a wiring path such as a wiring board 53 (see Figure 4). In the example shown in Figure 5, the light source unit 50 includes, for example, a light-emitting element 51r capable of emitting red light, a light-emitting element 51g capable of emitting green light, and a light-emitting element 51b capable of emitting blue light. Each of the multiple light-emitting elements 51 is, for example, a light-emitting diode element.

[0039] The pixel control circuit 71 generates a horizontal drive signal HDS and a vertical drive signal VDS based on the input signal VCSA. For example, in this embodiment, since it is driven in a field sequential manner, the horizontal drive signal HDS and the vertical drive signal VDS are generated for each color that the light source unit 50 can emit light. The gate drive circuit 72 sequentially selects gate lines GL of the display panel P2 (see Figure 3) within one vertical scanning period based on the horizontal drive signal HDS. The order of selection of gate lines GL is arbitrary. As shown in Figure 3, the multiple gate lines (signal wiring) GL extend in the X direction and are arranged along the Y direction.

[0040] The source drive circuit 73 supplies a gradation signal corresponding to the output gradation value of each pixel to each source line SL of the display panel P2 (see Figure 3) within one horizontal scanning period, based on the vertical drive signal VDS. As shown in Figure 3, the multiple source lines (signal lines) SL extend in the Y direction and are arranged along the X direction. One pixel is formed at each intersection of the gate line GL and the source line SL. A switching element Tr (see Figure 5) is formed at each intersection of the gate line GL and the source line SL. The multiple gate lines GL and multiple source lines SL shown in Figures 3 and 5 correspond to the multiple signal lines that transmit the drive signals that drive the liquid crystal LQ shown in Figure 4.

[0041] As the switching element Tr shown in Figure 5, for example, a thin-film transistor is used. The type of thin-film transistor is not particularly limited, and examples include the following. Classified by gate position, bottom-gate transistors or top-gate transistors can be cited. Also, classified by the number of gates, single-gate thin-film transistors and double-gate thin-film transistors can be cited. One of the source electrode and drain electrode of the switching element Tr is connected to the source line SL, the gate electrode is connected to the gate line GL, and the other of the source electrode and drain electrode is connected to one end of the capacitance of polymer-dispersed liquid crystal LC (liquid crystal LQ shown in Figure 4). One end of the capacitance of the polymer-dispersed liquid crystal LC is connected to the switching element Tr via the pixel electrode PE, and the other end is connected to the common potential wiring CML via the common electrode CE. Furthermore, a retaining capacitance HC is generated between the pixel electrode PE and the retaining capacitance electrode electrically connected to the common potential wiring CML. The potential supplied to the common potential wiring CML is supplied from the common potential driving circuit 74.

[0042] <Details of the light guide plate> Next, we will explain the details of the light guide plate. Figure 6 is a schematic plan view showing the path of light introduced into the light guide plate in a display panel, which is an example of a study for Figure 3.

[0043] The light guide plate 30 of the display panel P3 shown in Figure 6 includes a side surface 30s1 facing the light source unit 50 and extending along the first direction, a curved side surface 30s2 connected to one end of side surface 30s1, and a curved side surface 30s3 connected to the other end of side surface 30s2. In the examples shown in Figures 3 and 6, the light guide plate 30 also includes a side surface 30s4 opposite to side surface 30s1. Side surface 30s4 is also curved. This is the same as the display panel P2 shown in Figure 3. However, the display panel P3 differs from the display panel P2 shown in Figure 3 in that the entire side surface 30s1 facing the light source unit 50 is a flat surface. In other respects, the display panel P3 and the display panel P2 are the same, so redundant explanations are omitted.

[0044] As shown in Figure 6, in the case of the display panel P3, the light L50 emitted from each of the multiple light-emitting elements 51 of the light source unit 50 enters from the side surface 30s1 and travels linearly along the Y direction. Here, the display area DA is considered to be divided into three parts: display area DA1 which faces the light source unit 50 and has side surface 30s1, display area DA2 which has side surface 30s2, and display area DA3 which has side surface 30s3.

[0045] As described above, in the case of display panel P3, light L50 travels linearly along the Y direction, so the brightness of display area DA1 is extremely high compared to the brightness of display areas DA2 and DA3. In other words, the brightness of display areas DA2 and DA3 is dim because light L50 does not reach them sufficiently.

[0046] Furthermore, the inventors of this application experimentally confirmed that even when the range of the light source unit 50 is extended, as shown by the dotted line in Figure 6, and the side surface 30s2 or side surface 30s3 is positioned in front of the light-emitting element 51 in the Y direction, the brightness of the display area DA2 and the display area DA3 remains dim. This is thought to be because the incident angle when the light L50 enters the side surface 30s2 or side surface 30s3 is small, causing some or all of the light L50 to be reflected.

[0047] More specifically, each of the multiple light-emitting elements 51 is arranged linearly, for example, along the X direction. Therefore, light L50 incident on the side surface 30s1 perpendicular to the Y direction is hardly reflected, and almost all of the light L50 is introduced into the light guide plate 30. On the other hand, sides 30s2 and 30s3 are not perpendicular to the Y direction. Therefore, depending on the angle of incidence of the light L50, some or all of the light L50 is reflected by side surface 30s2 or side surface 30s3, and the amount of light introduced into the light guide plate 30 is small. As a result, sufficient brightness cannot be obtained in display areas DA2 and DA3.

[0048] In the display panel P2 shown in Figure 3 and the display panel P3 shown in Figure 6, it is preferable to make the brightness uniform from the viewpoint of improving display quality. In order to make the brightness uniform, it is necessary to reduce the unevenness in the density of light incident on the light guide plate. Specifically, when aiming to make the brightness of the display area DA uniform, structural features that supply light L50 to display areas DA2 and DA3 are necessary. The detailed structure of the display panel P2 shown in Figure 3 will be described below.

[0049] Figure 7 is an enlarged plan view showing the area around one end of the side of the light guide plate shown in Figure 3 that faces the light source. Figure 8 is an enlarged plan view showing the area around the other end of the side of the light guide plate shown in Figure 3 that faces the light source.

[0050] The light guide plate 30 of the display panel P2 shown in Figure 3 includes a side surface 30s1 facing the light source unit 50 and extending along the first direction, a curved side surface 30s2 connected to one end of side surface 30s1, and a curved side surface 30s3 connected to the other end of side surface 30s2. This is the same as the display panel P3 shown in Figure 6.

[0051] The side surface 30s1 of the light guide plate 30 of the display panel P2 includes region R1, region R2 located between region R1 and side surface 30s2 and connected to side surface 30s2, and region R3 located between region R1 and side surface 30s3 and connected to side surface 30s3. As shown in Figures 7 and 8, each of region R2 (see Figure 7) and region R3 (see Figure 8) is provided with a plurality of protrusions 33 that can change the direction of light propagation.

[0052] In the examples shown in Figures 7 and 8, each of the multiple protrusions 33 is a prism that is either conical or pyramidal in shape. Light L50 incident on one of the multiple protrusions 33 is refracted on the surface of the protrusion 33 in a direction inclined at an angle of less than 90 degrees with respect to the Y direction, and then travels straight through the light guide plate 30. In other words, a portion of the light L50 is refracted by the protrusion 33 and reaches the display area DA2 (see Figure 7) and the display area DA3 (see Figure 8). As a result, the brightness of the display areas DA2 and DA3 is increased, thereby improving the display quality of the display panel P2.

[0053] Incidentally, in this embodiment, as shown in Figures 7 and 8, no multiple protrusions 33 are formed in region R1. In other words, region R1 is a flatter surface than regions R2 and R3. From the viewpoint of improving the brightness of display regions DA2 and DA3, the direction of propagation of light L50 incident on the side surface 30s1 into region R2 shown in Figure 7 and region R3 shown in Figure 8 is important, and the shape of region R1 is not limited. For example, as a modification of this embodiment, region R1 may also have multiple protrusions 33 formed in it, similar to regions R2 and R3.

[0054] However, from the viewpoint of improving the overall brightness of the display panel P2, it is preferable that region R1 is flatter than regions R2 and R3, as in this embodiment. The multiple protrusions 33 are prisms capable of changing the direction of propagation of light L50, as described above. However, not all of the light L50 irradiated onto the multiple protrusions 33 is necessarily introduced into the light guide plate 30, and some of the light L50 may be reflected by the surface of the protrusions 33.

[0055] On the other hand, if region R1 is a flat surface as in this embodiment, region R1 can be positioned perpendicular to the Y direction toward the side surface 30s1 of the light guide plate 30 from the light source unit 50 (more specifically from each of the multiple light-emitting elements 51). In this case, the light L50 irradiated onto region R1 is hardly reflected, and almost the entire amount is introduced into the light guide plate 30. Therefore, from the viewpoint of the total amount of light L50 introduced into the light guide plate 30, it is preferable for region R1 to be a flat surface in that it is possible to increase the total amount of light L50.

[0056] Furthermore, in the example shown in Figure 3, in the Y direction from the light source unit 50 toward the side surface 30s1 of the light guide plate 30, side surfaces 30s2 and 30s3 are positioned so as not to face the light source unit 50. As a modification of this embodiment, as shown by the dotted line in Figure 6, the light source unit can be extended so that side surfaces 30s2 and 30s3 are positioned so as to face the light source unit 50 in the Y direction. However, as already explained, the inventors have found that even if the length of the light source unit 50 is extended in the X direction, a sufficient amount of light L50 will not be supplied to the display areas DA2 and DA3. Therefore, as in this embodiment, when side surfaces 30s2 and 30s3 are positioned so as not to face the light source unit 50, the number of light-emitting elements 51 used can be reduced, which is preferable from the viewpoint of cost or power consumption reduction.

[0057] <Examples of the shape of the protrusions> Next, we will describe examples of the shape of the protrusions 33. Figures 9 and 10 are perspective views showing examples of multiple protrusions formed on the light guide plate. Figure 11 is an enlarged cross-sectional view along line BB in Figure 9 or line CC in Figure 10. Note that both the enlarged cross-section along line BB in Figure 9 and the enlarged cross-section along line CC in Figure 10 have the shape shown in Figure 11.

[0058] In the example shown in Figure 9, each of the multiple protrusions 33 is conical. In the example shown in Figure 10, each of the multiple protrusions 33 is pyramidal. Although Figure 10 shows a square pyramid as an example of a pyramidal shape, variations may include triangular pyramids or polygonal pyramids of pentagons or more. Also, as shown in Figure 11, in a cross-sectional view along the XY plane, each of the multiple protrusions 33 forms a triangle. One of the three sides of the triangle is aligned along the X direction. The other two sides of the triangle are aligned to extend along directions intersecting the X and Y directions, respectively.

[0059] As schematically shown in Figure 11, the light L50 emitted from the light source unit 50 (more specifically, the light-emitting element 51) travels along the Y direction and illuminates the protrusion 33. A portion of the light L50 is refracted by the inclined surface of the protrusion 33 and travels as light L51 in directions different from the Y and X directions, respectively. Another portion of the light L50 is reflected multiple times by the inclined surface of the protrusion 33 and travels back towards the light source unit 50 as light L52, which is shown by a dotted line in Figure 11.

[0060] Figures 12 and 13 are perspective views showing modified examples of multiple protrusions formed on a light guide plate. Figure 14 is an enlarged cross-sectional view along the DD line in Figure 12 or the EE line in Figure 13. Note that both the enlarged cross-section along the DD line in Figure 12 and the enlarged cross-section along the EE line in Figure 13 have the shape shown in Figure 14.

[0061] In the example shown in Figure 12, each of the multiple protrusions 33 is a frustocone. In the example shown in Figure 13, each of the multiple protrusions 33 is a frustopyrocone. As shown in Figure 14, the apex of the multiple protrusions 33 (the upper base of the trapezoid) faces the light source 50. Also, in a cross-sectional view along the XY plane, each of the multiple protrusions 33 forms a trapezoid. The upper and lower bases of the trapezoid are aligned along the X direction. Furthermore, the other two of the four sides of the trapezoid are aligned to extend along directions intersecting the X and Y directions, respectively.

[0062] As schematically shown in Figure 14, the light L50 emitted from the light source unit 50 (more specifically, the light-emitting element 51) travels along the Y direction and illuminates the protrusion 33. A portion of the light L50 is refracted by the inclined surface of the protrusion 33 and travels as light L51 in directions different from the Y and X directions, respectively. Another portion of the light L50 is reflected multiple times by the inclined surface of the protrusion 33 and travels back towards the light source unit 50 as light L52, which is shown by a dotted line in Figure 14.

[0063] Furthermore, as shown in Figure 14, when each of the multiple protrusions 33 forms a trapezoid in cross-sectional view, a portion of the light L50 is directed onto the upper base of the trapezoid. The upper base of the trapezoid is positioned perpendicular to the direction of propagation of the light L50. In this case, since almost no reflection occurs at the upper base of the trapezoid, the amount of light introduced into the light guide plate 30 can be increased compared to the example shown in Figure 11.

[0064] Figure 15 is an enlarged cross-sectional view showing a modified example of the multiple protrusions shown in Figure 11. The layout of the modified example shown in Figure 15 differs from the layout shown in Figure 11 in that it has flat portions (flat portions 33F) between the multiple adjacent protrusions 33. Specifically, each of the regions R2 and R3 of the side surface 30s1 has flat portions between the multiple adjacent protrusions 33.

[0065] As schematically shown in Figure 15, the light L50 emitted from the light source unit 50 (more specifically, the light-emitting element 51) travels along the Y direction and illuminates the protrusion 33. A portion of the light L50 is refracted by the inclined surface of the protrusion 33 and travels as light L51 in directions different from the Y and X directions, respectively. Another portion of the light L50 is reflected multiple times by the inclined surface of the protrusion 33 and travels back towards the light source unit 50 as light L52, which is shown by a dotted line in Figure 14.

[0066] Furthermore, as shown in Figure 15, if a flat portion (flat portion 33F) is provided between a plurality of adjacent protrusions 33, a portion of the light L50 is irradiated onto the flat portion 33F. The flat portion 33F is positioned perpendicular to the direction of propagation of the light L50. In this case, since almost no reflection occurs in the flat portion 33F, the amount of light introduced into the light guide plate 30 can be increased compared to the example shown in Figure 11.

[0067] Although Figure 15 is shown as a modification of Figure 11, a further modification of the modification shown in Figure 15 can be combined with the modification shown in Figure 14. That is, the multiple protrusions 33 may be frustoconical or truncated pyramidal, and flat sections 33F, as shown in Figure 15, may be arranged between adjacent protrusions. In this case, the amount of light introduced into the light guide plate 30 can be further increased. On the other hand, the amount of light L51 traveling in directions different from the Y and X directions is less compared to the examples shown in Figure 14 and Figure 15.

[0068] Figure 16 is a perspective view showing another modification of the multiple protrusions shown in Figure 12. Figure 17 is an enlarged cross-sectional view along the FF line in Figure 16. Figure 18 is an enlarged cross-sectional view showing an example of the shape of the protrusions in the region opposite to the region shown in Figure 17. Each of the multiple protrusions 33 shown in Figures 16 to 18 differs from the multiple protrusions 33 shown in Figures 12 to 14 in that its cross-sectional shape is that of a saw blade. In Figures 16 and 17, an example of the shape of the protrusion 33 located in region R2 shown in Figure 7 is illustrated. In this modification, the shape of the protrusion 33 located in region R3 shown in Figure 8 is illustrated in Figure 18.

[0069] In the examples shown in Figures 17 and 18, each of the multiple protrusions 33 forms a triangle in a cross-sectional view (more specifically, a cross-sectional view along the XY plane, including the X and Y directions). One of the three sides of the triangle is aligned along the X direction. Another of the three sides of the triangle is aligned along the Y direction. Furthermore, the remaining side of the triangle extends in a direction intersecting both the X and Y directions.

[0070] As schematically shown in Figures 17 and 18, the light L50 emitted from the light source 50 (more specifically, the light-emitting element 51) travels along the Y direction and illuminates the protrusion 33. A portion of the light L50 is refracted by the inclined surface of the protrusion 33 and travels as light L51 in directions different from the Y and X directions, respectively. Another portion of the light L50 is reflected by the inclined surface of the protrusion 33.

[0071] However, in this modified example, most of the light reflected from the inclined surface of the protrusion 33 is introduced into the light guide plate 30 from a surface along the Y direction. Therefore, in this modified example, the light L52 shown by the dotted line in Figures 11, 14, and 15 is hardly generated. In other words, according to this modified example, since most of the light L50 irradiated from the light source 50 (more specifically the light-emitting element 51) is introduced into the light guide plate 30, if the light L50 is kept constant, the brightness can be increased to the highest level among the multiple embodiments described above.

[0072] Figures 19 and 20 are enlarged cross-sectional views showing other modifications of Figure 11. Figure 19 is an enlarged cross-sectional view of region 2 shown in Figure 7, and Figure 20 is an enlarged cross-sectional view of region R3 shown in Figure 8.

[0073] The examples shown in Figures 19 and 20 differ from the embodiment shown in Figure 11 in that a lens 34 is positioned between the light guide plate 30 and the light source unit 50. In the examples shown in Figures 18 and 19, the display device further includes a lens 34 positioned between the side surface 30s1 of the light guide plate 30 and the light source unit 50. As shown in Figures 19 and 20, the light L50 emitted from the light source unit 50 travels along the Y direction from the light source unit 50 to the lens 34, and then travels along a direction inclined with respect to the Y direction (the θ1 direction in Figure 19 and the θ2 direction in Figure 20) from the lens 34 to the light guide plate 30.

[0074] In this modified example, as shown in Figures 19 and 20, light L50 can be incident on the inclined surfaces of the multiple protrusions 33 from a direction perpendicular to them. Therefore, in this modified example, almost no light L52 is generated, as shown by the dotted line in Figures 11, 14, and 15. In other words, according to this modified example, almost all of the light L50 irradiated from the light source unit 50 (more specifically, the light-emitting element 51) is introduced into the light guide plate 30 via the lens 34, so if the light L50 is kept constant, the brightness can be increased to the highest level among the multiple embodiments described above.

[0075] Note that the direction in which light L50 is refracted differs between region R2 shown in Figure 19 and region R3 shown in Figure 20. Therefore, the optical properties of lens 34A shown in Figure 19 and lens 34B shown in Figure 20 are different. Specifically, lens 34A shown in Figure 19 has optical properties that refract light L50 so that it travels toward the left side of the paper. On the other hand, lens 34B shown in Figure 20 has optical properties that refract light L50 so that it travels toward the left side of the paper. In this case, in the display panel P2 shown in Figure 3, light L51 is supplied to display region DA2 via lens 34A shown in Figure 19, and light L51 is supplied to display region DA3 via lens 34B shown in Figure 20.

[0076] Figure 21 is an enlarged cross-sectional view showing another modification of Figure 11. The modification shown in Figure 21 differs in that each of the multiple protrusions 33 is formed separately from the substrate (glass substrate 33G) that constitutes the light guide plate 30. Each of the multiple protrusions 33 described using Figures 11 to 20 is formed integrally with the substrate (e.g., glass substrate) of the light guide plate 30. For this reason, each of the multiple protrusions 33 is made of, for example, glass.

[0077] On the other hand, in the modified example shown in Figure 21, the light guide plate 30 includes a glass substrate 30G and a light-transmitting resin layer 30R formed on the glass substrate 30G. Each of the multiple protrusions 33 is made of the light-transmitting resin layer 30R.

[0078] As shown in this modified example, when each of the multiple protrusions 33 is formed separately from the glass substrate 30G, the degree of freedom in selecting the material for the protrusions 33 is improved. Furthermore, when a resin layer 30R is used as the protrusion 33, the molding of the protrusions 33 is easy, thus improving the degree of freedom in the shape of the protrusions 33. Note that Figure 21 shows a modified example from Figure 11 as a representative example, but in some cases, one of the multiple protrusions 33 shown in Figures 14, 15, and 17 to 20 may be formed from a resin layer 30R (see Figure 21).

[0079] In this modified example, as described above, it is preferable from the viewpoint of improving the degree of freedom in selecting the material for the protrusion 33 or the degree of freedom in the shape of the protrusion 33. On the other hand, when the protrusion 33 is formed from a material different from the glass substrate 30G, the light L51 may be refracted at the interface between the protrusion 33 and the glass substrate 30G. From the viewpoint of preventing the refraction of light L51, it is preferable that each of the multiple protrusions 33 is formed integrally with the glass substrate 30G.

[0080] Although embodiments and representative modifications have been described above, the technology described can be applied to various modifications other than those exemplified. For example, the modifications described above may be combined.

[0081] Within the scope of the spirit of the present invention, a person skilled in the art can conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the scope of the present invention. For example, any addition, deletion, or design change of components, or addition, omission, or modification of processes, made by a person skilled in the art to the above-described embodiments, is also included within the scope of the present invention, as long as it retains the gist of the present invention. [Explanation of Symbols]

[0082] 10,20 boards 10b,20b,30b Back side (principal surface, surface) 10f,20f,30f Front (main surface, surface) 11,53 Wiring board 30 Light guide plate 30G glass substrate 30R resin layer 30s,30s1,30s2,30s3,30s4 side 32 Adhesive layer 33 Convex part 34, 34A, 34B lenses 50 Light source section 50S circuit board 51, 51b, 51g, 51r light-emitting element 52 Light source control unit 70 Drive Circuit 71 Pixel control circuit 72 Gate drive circuit 73 Source drive circuit 74 Common Potential Drive Circuit 90 Control Unit 91 Control circuits 92 Signal Processing Circuits 921 Input signal analysis unit (input signal analysis circuit) 922 Memory section (memory circuit) 923 Signal Adjustment Section 100 Observers 101 Background CE Common Electrode CMF1, CMF2 Power Supply Section CML Common Potential Wiring DA display area DSP1,DSP2 Display device P1, P2, P3 Display Panel (Display Device) GL gate wire (signal wiring) HC retention capacity HDS horizontal drive signal L50 light L2 emission light LCSA light source control signal LQ LCD LQL liquid crystal layer PE pixel electrode PFA surrounding area (frame area) R1,R2,R3 area RF light reflective film SL source line (signal wiring) SLM seal section Tr switching element VCS,VCSA,VS input signal VDS Vertical Drive Signal

Claims

1. A first substrate having a first front surface and a first rear surface on the opposite side of the first front surface, A liquid crystal layer disposed on the first front surface of the first substrate, A light guide plate having a second back surface facing the first front surface via the liquid crystal layer, and a second front surface on the opposite side of the second back surface, A display area located in a position that overlaps with a portion of the light guide plate, A light source unit including multiple light-emitting elements, It has, The light guide plate is A first side surface facing the light source and extending along the first direction, A second side surface that is connected to one end of the first side surface and has a curved surface, A third side surface that is connected to the other end of the second side surface and has a curved surface, Includes, The first aspect is, The first area and, A second region located between the first region and the second side surface, and connected to the second side surface, A third region located between the first region and the third side surface, and connected to the third side surface, Includes, A display device wherein each of the second and third regions is provided with a plurality of protrusions capable of changing the direction of light propagation.

2. In claim 1, A display device in which the first region is a flatter surface than the second and third regions, respectively.

3. In claim 2, In the second direction toward the first side surface of the light guide plate from the light source unit, A display device in which the second side and the third side are each positioned so as not to face the light source.

4. In claim 3, A display device in which each of the plurality of protrusions is conical or pyramidal in shape, with its apex facing the light source.

5. In claim 3, A display device in which each of the plurality of protrusions is a frustoconical or truncated pyramidal shape with its top surface facing the light source.

6. In claim 3, A display device wherein each of the second and third regions of the first side surface has a flat portion between the plurality of adjacent protrusions.

7. In claim 3, In a cross-sectional view, Each of the aforementioned multiple protrusions forms a triangle, One of the three sides of the aforementioned triangle is positioned along the first direction, A display device in which one of the three sides of the aforementioned triangle is positioned along the second direction.

8. In claim 3, The light guide plate further comprises a lens disposed between the first side surface and the light source unit. The light emitted from the aforementioned light source unit is The light source unit proceeds along the second direction to the lens, A display device wherein the lens and the light guide plate are located along a third direction that is inclined with respect to the second direction.

9. In claim 1, The light guide plate is Glass substrate and A light-transmitting resin layer formed on the glass substrate, Includes, A display device in which each of the plurality of protrusions is made of the light-transmitting resin layer.

Images