On-vehicle display device, and method of manufacturing the same

Abstract

To provide an on-vehicle display device capable of enhancing visibility, and a method of manufacturing the same.SOLUTION: An on-vehicle display device 10 comprises: a display panel 1 having a display area 11 that radiates light to display information; and a cover panel 2 disposed in front of the display panel 1, and through which light from the display panel 1 passes. A luminous reflectance R of the cover panel 2 in a range corresponding to the display area 11 and a white luminance B being a maximum luminance of the display panel 1 through the cover panel 2 are set to satisfy a formula: B (cd / m2)≥4500×R+100.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an in-vehicle display device and a manufacturing method thereof. [Background technology]

[0002] The display device mounted on a vehicle described in Patent Document 1 comprises a display having a screen, a wall to which the display is attached, and a display control unit that displays an information image on a portion of the screen and also displays a wall image having the same texture, color or pattern as the wall in the area of ​​the screen where the information image is not displayed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-131729 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, when the screen and the wall are illuminated by external light, the reflected light of the external light becomes larger than the light showing the information image, and the visibility of the information image deteriorates, which is called washout. Thus, there is room for improvement in terms of visibility.

[0005] The present disclosure has been made in consideration of the above-described circumstances, and has an object to provide an in-vehicle display device capable of improving visibility and a manufacturing method thereof. [Means for solving the problem]

[0006] In order to achieve the above object, an in-vehicle display device according to a first aspect of the present disclosure includes: a display panel having a display area that displays information by emitting light; a cover panel disposed in front of the display panel, the cover panel transmitting light from the display panel and reflecting external light; The luminous reflectance R of the cover panel in the range corresponding to the display area and the maximum luminance B of the display panel through the cover panel are set so as to satisfy the following (Equation 1). B(cd / m 2 )≧4500×R+100 (Formula 1)

[0007] In order to achieve the above object, a manufacturing method of an in-vehicle display device according to a second aspect of the present disclosure includes: A reflectance acquisition unit acquires information about the luminous reflectance R; and a step of a setting unit setting the luminance B that satisfies the above (Formula 1) based on the acquired luminous reflectance R to the in-vehicle display device. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide an in-vehicle display device capable of improving visibility and a manufacturing method thereof. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a vehicle interior in which an in-vehicle display device according to an embodiment of the present disclosure is mounted; [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line II-II of FIG. 1 according to the embodiment. [Diagram 3] 6 is a graph showing the relationship between luminous reflectance R and white luminance B that can realize a sufficient contrast ratio under each external light condition, obtained by an experiment according to the embodiment of the present invention. [Figure 4] FIG. 2 is a block diagram of the brightness setting device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An in-vehicle display device and a manufacturing method thereof according to an embodiment of the present disclosure will be described with reference to the drawings. As shown in FIG. 1, the in-vehicle display device 10 is mounted on a dashboard 13 of a vehicle. The in-vehicle display device 10 includes a display area 11 and an icon lighting section 12. The display area 11 is an area where various information is displayed. The icon lighting section 12 is an area where warning icons are illuminated. The display area 11 is rectangular in shape. The icon lighting section 12 is circular with an area smaller than that of the display area 11, and is located next to the display area 11 in the vehicle width direction (more precisely, in the left direction Ld as seen by the viewer). The display area 11 and the icon lighting section 12 are disposed between the driver's seat and the passenger seat on the dashboard 13. The display area 11 and the icon lighting section 12 display by emitting light through a cover panel 2 (more precisely, a light-transmitting design layer 23, described later) having a pattern such as wood grain.

[0011] As shown in FIG. 2, the in-vehicle display device 10 includes a cover panel 2, a display panel 1, an outer case 3, an inner case 31, a circuit board 4, a control unit 60, a light source 41, a light-transmitting adhesive 5, and a backlight unit 7. In the following description, the upward direction Ud, downward direction Dd, left direction Ld, and right direction Rd are defined based on the viewpoint of the viewer of the in-vehicle display device 10, the direction toward the viewer is defined as the forward direction Fd, and the direction toward the viewer is defined as the rearward direction Bd.

[0012] The backlight unit 7 illuminates the rear surface of the display panel 1. The backlight unit 7 includes a plurality of light sources 7a that emit illumination light, as well as a well-known light guide, a reflective sheet, an optical sheet, and a housing made of a metal such as aluminum that houses these components, all of which are not shown. The plurality of light sources 7a are arranged in a matrix at positions facing the rear surface of the display panel 1. Each light source 7a is made of an LED (Light Emitting Diode) and emits light at a set brightness under the control of a control unit 60, which will be described later.

[0013] The display panel 1 is a rectangular plate that is long in the left-right directions Ld, Rd. The display panel 1 has a display area 11 on its surface in the front direction Fd. The display panel 1 is made up of a TFT (Thin Film Transistor) type liquid crystal display panel (LCD: Liquid Crystal Display) in which pixels made up of multiple RGB colors are arranged in a matrix.

[0014] The display panel 1 includes a liquid crystal layer 1a, a pair of glass substrates 1b, 1c on both sides of the liquid crystal layer 1a, on which transparent electrodes are formed using ITO (Indium Tin Oxide) or the like, and a pair of polarizing plates 1d, 1e arranged to sandwich the pair of glass substrates 1b. Red (R), green (G), and blue (B) color filters (not shown) are arranged for each pixel on the surface of the glass substrate 1b facing the liquid crystal layer 1a. The pair of polarizing plates 1d, 1e are arranged so that their transmission axes are substantially perpendicular to each other. The polarizing plate 1d is located on the cover panel 2 side. The polarizing plate 1e is located on the circuit board 4 side.

[0015] The display panel 1 is electrically connected to the circuit board 4 so as to be able to receive a control signal via a connection cable (not shown). Based on a control signal from a control unit 60 provided on the circuit board 4, the orientation of liquid crystal molecules in the liquid crystal layer 1a of the display panel 1 is controlled, and the RGB transmittance of each pixel of the display panel 1 is changed, thereby displaying an image in the display area 11 with desired color and brightness. When displaying white on the display panel 1, each color of the RGB values ​​is set to the maximum value by the control unit 60. Specifically, when each color of the RGB values ​​is expressed by an integer value from 0 to 255, white is displayed by setting all of the colors of the RGB values ​​to 255.

[0016] The display panel 1 is a normally black type liquid crystal display panel that displays black when no voltage is applied to the display panel 1. Specifically, when a voltage is applied via a transparent electrode to the liquid crystal layer 1a corresponding to a specific pixel, the liquid crystal layer 1a twists the light from the backlight unit 7 by 90 degrees when the light passes through the liquid crystal layer 1a, aligning the polarization direction of the light with the transmission axis of the polarizer 1d. This allows the light from the backlight unit 7 to pass through the polarizer 1d, causing the specific pixel to emit light. On the other hand, when no voltage is applied to the liquid crystal layer 1a corresponding to a given pixel, the liquid crystal layer 1a maintains the polarization direction of the light along the absorption axis of the polarizer 1d without twisting the light from the backlight unit 7 when the light passes through the liquid crystal layer 1a. As a result, the light from the backlight unit 7 is blocked by the polarizer 1d, and the given pixel turns black.

[0017] The light-transmitting adhesive 5 is made of an optical bonding agent, and adheres the front surface of the display panel 1 to the rear surface of a light-transmitting base material 21 (described later) of the cover panel 2. The light-transmitting adhesive 5 has a rectangular plate shape including the display area 11. In addition to the function of fixing the display panel 1 to the light-transmitting base material 21, the light-transmitting adhesive 5 has a function as a spacer that ensures a gap between the display panel 1 and the light-transmitting base material 21, and a function of guiding light from the display panel 1 to the light-transmitting base material 21.

[0018] The circuit board 4 is a PCB (Printed Circuit Board) and is located behind the display panel 1. On the circuit board 4, a control unit 60 (for example, a microcontroller) that controls the operation of the in-vehicle display device 10, a light source 41, and other electronic components are mounted. The light source 41 is made up of an LED (Light Emitting Diode), and emits light at a brightness set under the control of a control unit 60, which will be described later.

[0019] The outer case 3 is made of light-shielding resin or metal, and is formed in a box shape that is open in the forward direction Fd. The display panel 1, the middle case 31, and the circuit board 4 are housed inside the outer case 3. An end face of the outer case 3 in the forward direction Fd contacts the rear face of the cover panel 2 (more precisely, the light-shielding layer 22 described later).

[0020] The inner case 31 is made of light-shielding resin or metal, and contains the display panel 1 and the light source 41. The inner case 31 is disposed between the front surface of the circuit board 4 and the rear surface of the cover panel 2 (more precisely, the light-shielding layer 22 described later). The inner case 31 includes a light guide section 31a that guides light from the light source 41 to the icon lighting section 12.

[0021] The cover panel 2 is formed so as to cover the opening of the outer case 3 in the forward direction Fd, and is formed as a long plate member in the left-right directions Ld, Rd exposed on the front side of the dashboard 13 (see FIG. 1). The cover panel 2 may be formed in a flat plate shape, or may be formed in a curved plate shape corresponding to the shape of the vehicle dashboard 13. When the cover panel 2 is formed in a curved plate shape, it may be curved so as to bulge in the forward direction Fd toward the viewer in the up-down directions Ud and Dd.

[0022] The cover panel 2 includes a light-transmitting substrate 21, a light-shielding layer 22, and a light-transmitting design layer 23. A light-transmitting design layer 23 is laminated on the front surface of the light-transmitting substrate 21, and a light-shielding layer 22 is laminated on the rear surface of the light-transmitting substrate 21.

[0023] The light-transmitting substrate 21 is a plate-shaped member made of a light-transmitting material such as acrylic resin (PMMA: Poly Methyl Methacrylate) or soda lime glass. The light-transmitting substrate 21 may or may not be completely transparent, and may be colored to reduce light transmittance, for example.

[0024] The light-shielding layer 22 is formed so as to hide the internal structure of the in-vehicle display device 10 from the viewer. The light-shielding layer 22 is an ink layer formed by printing black-based ink. The light-shielding layer 22 is not formed in the area corresponding to the display area 11 and the area corresponding to the icon shape of the icon lighting unit 12 on the rear surface of the light-transmitting base material 21, and light is transmitted through these areas.

[0025] The light-transmitting design layer 23 is a light-transmitting layer having a light-transmitting pattern of wood grain, metal, fabric, or leather. This pattern is formed by applying light-transmitting printing, which is printing that allows light to pass, to the front surface of the light-transmitting base material 21. Light-transmitting design layers 23 with lighter color tones tend to have higher reflectance, while light-transmitting design layers 23 with darker color tones tend to have lower reflectance. The reflectance of the light-transmitting design layer 23 will be described later. When light representing an image is not emitted from the display area 11, only the pattern of the light-transmitting design layer 23 appears to the outside when exposed to external light (e.g., sunlight or outdoor light). When light representing an image is emitted from the display area 11, the image appears visible through the pattern of the light-transmitting design layer 23. Furthermore, when light is emitted from the light source 41 into the icon-shaped cutout portion of the light-shielding layer 22, the icon appears visible through the pattern of the light-transmitting design layer 23. The light-transmitting design layer 23 may be formed on the rear surface of the light-transmitting base material 21. In this case, the light-shielding layer 22 may be formed on the rear surface of the light-transmitting design layer 23. The light-transmitting design layer 23 may be formed on both the front and rear surfaces of the light-transmitting base material 21.

[0026] The control unit 60 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a power supply circuit that controls the power supply of the in-vehicle display device 10, and the like. The control unit 60 displays an image on the display panel 1 and controls the lighting of the light sources 7a and 41. The control unit 60 acquires various information from the vehicle's ECU (Electronic Control Unit), and displays an image including information on the display panel 1 based on the acquired information. The control unit 60 adjusts the RGB values ​​of each pixel of the display panel 1 to light up each pixel with a desired color and brightness.

[0027] Next, the relationship between the luminous reflectance R, which is an index indicating the reflectance of the light-transmitting design layer 23, and the white luminance B of the display panel 1 through the cover panel 2 will be described. The luminous reflectance R is the luminous reflectance including specular reflection light taking into account the standard spectral luminous efficiency V(λ). The light-transmitting design layer 23 has a mottled or geometric pattern to express the texture of the material. The luminous reflectance R is not the reflectance of a specific color of a part of the light-transmitting design layer 23, but is the average reflectance of the area of ​​the light-transmitting design layer 23 that overlaps the display area 11.

[0028] The white luminance B of the display panel 1 through the cover panel 2 is the maximum luminance of the display area 11 visible to the viewer. When the display panel 1 is turned on at maximum luminance, all of the RGB values ​​of the pixels are set to their maximum values ​​by the control unit 60. Since the white luminance B is the luminance of the light from the display panel 1 transmitted through the cover panel 2 and the light-transmitting adhesive 5, it is lower than the emission luminance of the display panel 1 itself by at least the amount of light absorption and reflection by the cover panel 2 and the light-transmitting adhesive 5.

[0029] Here, the texture and design of the light-transmitting design layer 23 of the cover panel 2 become visible when the external light is reflected by the cover panel 2 and reaches the viewer. For this reason, a certain degree of luminous reflectance is required for the cover panel. On the other hand, in a cover panel with an excessively large luminous reflectance, the amount of reflected external light becomes significantly larger than the display luminance of the display area 11 depending on the external light. This reduces the contrast ratio considering the external light, and the visibility of the display area 11 becomes poor. Thus, in the past, it was unclear what conditions the illuminance of the external light, the reflectance of the cover panel 2 (luminous reflectance R), and the display luminance of the display area 11 (white luminance B) must satisfy to obtain sufficient visibility, but the inventors of the present application have found a condition that obtains good visibility. The condition will be described below.

[0030] The white luminance B and the luminous reflectance R are set so as to satisfy the following condition (Equation 1). B(cd / m 2 )≧4500×R+100 (Formula 1) As a result, the higher the luminous reflectance R of a cover panel 2 that is used, the higher the white luminance B is set, and sufficient image visibility can be obtained even when affected by external light. The luminous reflectance R is expressed as a value between 0 and 1. For example, when the luminous reflectance is 10% in percentage notation, 0.1 is substituted as the luminous reflectance R in the above (Equation 1).

[0031] Next, a method for deriving the above formula (1) will be described. The contrast ratio of "white (maximum brightness)" to "black (minimum brightness)" in the display area 11 taking into account external light decreases as the illuminance of the external light increases, deteriorating visibility, but from the viewpoint of visibility, it is desirable for the contrast ratio taking into account external light to be 3:1 or more. The relationship between the luminous reflectance R and white luminance B for each illuminance of external light to obtain this contrast ratio was obtained through an experiment. The results of this experiment are shown in the graph of Figure 3. In this experiment, the luminous reflectance R was measured with a spectrophotometer in accordance with JIS Z 8701, and specifically, it was obtained as the average value of the measured values ​​at multiple points in the region of the cover panel 2 corresponding to the display area 11. The white luminance B is measured by a luminance sensor disposed in the forward direction Fd of the cover panel 2. In this experiment, the white luminance B was obtained as a measured value, but as a theoretical value, it can be obtained by multiplying the luminance of the backlight unit 7 by the transmittance of the display panel 1 when displaying white and the transmittance of the cover panel 2 (light-transmitting substrate 21 and light-transmitting design layer 23).

[0032] In the graph of FIG. 3, the horizontal axis is luminous reflectance R, and the vertical axis is white luminance B. In this experiment, the white luminance B was set to 300 to 1000 cd / m for each of different external light conditions. 2 The luminous reflectance R that can obtain the above contrast ratio (3:1) within the range is obtained. As a result, lines L1 to L4 for each external light condition are obtained. Each line L1 to L4 is a directly proportional straight line obtained by drawing an approximation line using the least squares method or the like from the plot obtained by the experiment.

[0033] In this experiment, the illuminance of the external light irradiated on the in-vehicle display device 10 was set under four conditions: 60,000 Lx (lux), 50,000 Lx, 40,000 Lx, and 30,000 Lx. Line L1 indicates the relationship between luminous reflectance R and white luminance B that provides the above contrast ratio (3:1) under conditions where the illuminance of external light is 60,000 Lx. Line L2 indicates the relationship between luminous reflectance R and white luminance B that provides the above contrast ratio (3:1) under conditions where the illuminance of external light is 50,000 Lx. Line L3 indicates the relationship between luminous reflectance R and white luminance B that provides the above contrast ratio (3:1) under conditions where the illuminance of external light is 40,000 Lx. Line L4 indicates the relationship between luminous reflectance R and white luminance B that provides the above contrast ratio (3:1) under conditions where the illuminance of external light is 30,000 Lx. The slope relationship between the lines L1 to L4 is "L1>L2>L3>L4". This graph also shows that even with the same luminous reflectance R, the white luminance B required to obtain a sufficient contrast ratio increases as the illuminance of external light increases. In other words, even with the same white luminance B, the luminous reflectance R needs to be set lower in order to obtain a sufficient contrast ratio as the illuminance of external light increases.

[0034] In this embodiment, the above formula (1) is obtained from the line L3, and the white luminance B and luminous reflectance R are determined from this formula (1). The reason why line L3 among lines L1 to L4 is used as the criterion for determining the luminous reflectance R and the white luminance B will be described. In this embodiment, when the illuminance of external light is 30,000 Lx, for example, when the in-vehicle display device 10 is a vehicle instrument with a visor (not shown), the amount of reflected external light is not so large that it deteriorates visibility, so line L4 is excluded from the criterion for determining the luminous reflectance R and the white luminance B. In addition, since the power consumption increases as the white luminance B increases, in this embodiment, from the viewpoint of power saving, lines L1 and L2 are also excluded from the criterion for determining the luminous reflectance R and the white luminance B, and line L3 is used as the criterion for determining the luminous reflectance R and the white luminance B.

[0035] Next, a description will be given of a method for setting the white luminance B. This setting method is performed by a luminance setting device 70 shown in FIG. The luminance setting device 70 is made up of a computer. The luminance setting device 70 includes a processing unit 71 made up of a CPU, a storage unit 72 made up of a ROM and a RAM, and an input unit 73 operated by a designer. The storage unit 72 stores an operation program PG of the luminance setting device 70 and the above (Equation 1). The processing unit 71 includes, as functional blocks, a reflectance acquisition unit 71a that acquires a luminous reflectance R, a luminance acquisition unit 71b that acquires a white luminance B from the luminous reflectance R, and a luminance setting unit 71c that sets the acquired white luminance B as a maximum luminance value in the in-vehicle display device 10. Note that the storage unit 72 may store not only the above (Formula 1), but also a data table.

[0036] First, the designer measures the luminous reflectance R using a spectrophotometer, and inputs the measured luminous reflectance R to the luminance setting device 70 via the input unit 73. As a result, the reflectance acquisition unit 71a acquires the measured luminous reflectance R (its average value, to be precise). The designer may input the luminous reflectance R as a theoretical value into the luminance setting device 70 without measuring the luminous reflectance R.

[0037] Next, the luminance acquisition unit 71b acquires white luminance B by substituting the acquired luminous reflectance R into the above (Equation 1). For example, when the acquired luminous reflectance R is 0.1, the luminance acquisition unit 71b acquires white luminance B of 550 cd / m 2 Get the. The luminance acquisition unit 71b may acquire the white luminance B from the acquired luminous reflectance R by referring to a data table according to the above (Equation 1).

[0038] Finally, the luminance setting unit 71c sets the luminance that realizes the acquired white luminance B in the in-vehicle display device 10 (more precisely, the control unit 60) as the maximum luminance. This allows the control unit 60 to display an image in the display area 11 so that the luminance through the cover panel 2 becomes the acquired white luminance B. Here, as described above, the white luminance B is the luminance of the display panel 1 through the cover panel 2. Therefore, the actual emission luminance of the display panel 1 for realizing the white luminance B is a luminance that is greater than the white luminance B by at least the amount of light absorption and reflection of the cover panel 2 and the light-transmitting adhesive 5. The emission luminance of the display panel 1 is adjusted by adjusting the transmittance of the display area 11 and the emission luminance of the light source 7a. This completes the setting of white luminance B.

[0039] (effect) According to the embodiment described above, the following effects are achieved. (1) An in-vehicle display device 10 includes a display panel 1 having a display area 11 that displays information by emitting light, and a cover panel 2 that is disposed in front of the display panel 1 and transmits light from the display panel 1. The luminous reflectance R of the cover panel 2 in the range corresponding to the display area 11 and the white luminance B, which is the maximum luminance of the display panel 1 through the cover panel 2, are set to satisfy the above (Formula 1). According to this configuration, the white luminance B that satisfies the above formula (1) is set so that the visibility of the display in the display area 11 is not reduced by reflected light associated with external light. Therefore, the visibility of the display in the display area 11 can be improved.

[0040] (2) The cover panel 2 includes a light-transmitting base material 21 through which light from the display panel 1 transmits, and a light-transmitting design layer 23 that is formed on the front surface of the light-transmitting base material 21 close to the viewer and in an area that includes the display area 11 as seen from the viewer, and transmits light from the display panel 1 and reflects external light with a luminous reflectance R. The light-transmitting design layer 23 has a wood grain pattern, a metal pattern, a fabric pattern, or a leather pattern. According to this configuration, even if information is displayed so as to overlap the light-transmitting design layer 23, by setting a white luminance B that satisfies the above (Equation 1), the visibility of the display in the display area 11 when illuminated by external light can be improved.

[0041] (3) The manufacturing method of the in-vehicle display device 10 includes a step in which a reflectance acquisition unit 71a acquires information regarding the luminous reflectance R, a luminance acquisition unit 71b acquires a white luminance B that satisfies the above (Equation 1) based on the acquired luminous reflectance R, and a step in which a luminance setting unit 71c, which is an example of a setting unit, sets the luminance that realizes the acquired white luminance B in the in-vehicle display device 10. According to this configuration, the white luminance B is set so as to satisfy the above formula (1), and the visibility of the display in the display area 11 when illuminated by external light can be improved.

[0042] The present invention is not limited to the above-described embodiment and drawings. Modifications (including the deletion of components) can be made as appropriate within the scope of the present invention. An example of a modification will be described below.

[0043] (Modification) In the above embodiment, the above formula 1 is obtained from the line L3, and the white luminance B and the luminous reflectance R are determined from this formula 1. However, without being limited to this, the following formula 2 may be obtained from the line L2, and the white luminance B and the luminous reflectance R may be determined from this formula 2. This can improve visibility when the illuminance of external light is 50,000 Lx or less. B(cd / m 2 )≧5800×R+100 (Formula 2) Furthermore, the following (Formula 3) may be obtained from the line L1, and the white luminance B and the luminous reflectance R may be determined from this (Formula 3). This makes it possible to improve visibility when the illuminance of external light is 60,000 Lx or less. B(cd / m 2 )≧7000×R+100...(Formula 3)

[0044] In the above embodiment, when the pattern of the cover panel 2, i.e., the luminous reflectance R, differs depending on the vehicle model or specifications on which the in-vehicle display device 10 is mounted, the white luminance B may be set according to the vehicle model or specifications. In this case, the luminance setting device 70 may be configured as a part of the control unit 60 of the in-vehicle display device 10. For example, information indicating the type (vehicle model or specifications) of the cover panel 2 is input to the control unit 60. A data table in which the type of the cover panel 2 and the white luminance B are associated with each other is stored in a storage unit made of a ROM or the like of the control unit 60. Since the luminous reflectance R differs depending on the type of the cover panel 2, the luminous reflectance R and the white luminance B are indirectly associated with each other in this data table. Therefore, the information indicating the type of the cover panel 2 corresponds to information regarding the luminous reflectance R. When the control unit 60 acquires the information indicating the type of the cover panel 2, the control unit 60 may acquire the white luminance B by referring to the data table from the information indicating the type of the cover panel 2, and set the acquired white luminance B as the maximum luminance. This makes it possible to set the white luminance B (maximum luminance) according to the type of the cover panel 2.

[0045] In the above embodiment, the light-transmitting design layer 23 has a pattern printed on it, but it may be made of real wood, metal, fabric, leather, etc., instead of a printed pattern. In this case, the light-transmitting design layer 23 is formed thin enough to allow light to pass through the wood, etc. In the above embodiment, the icon lighting unit 12 may be omitted. In the above embodiment, the light-transmitting adhesive 5 may be omitted. In the above embodiment, the light-shielding layer 22 of the cover panel 2 may be omitted. Also, the light-transmitting design layer 23 of the cover panel 2 may be omitted. In the above embodiment, a touch sensor (not shown) may be interposed between the display panel 1 and the cover panel 2 to enable touch operation.

[0046] In the above embodiment, the control unit 60 may set the white luminance B as the maximum luminance according to the detection result of the illuminance sensor that detects the illuminance of the external light. In this case, the control unit 60 may set the white luminance B as the maximum luminance according to the above (Formula 1) when the illuminance of the detected external light is less than 45,000 Lx, set the white luminance B as the maximum luminance according to the above (Formula 2) when the illuminance of the detected external light is within the range of 45,000 to 55,000 Lx, and set the white luminance B as the maximum luminance according to the above (Formula 3) when the illuminance of the detected external light exceeds 55,000 Lx. Furthermore, the white luminance B may be set from an equation or a data table obtained by interpolating between the lines L1 to L4 according to the illuminance of the external light.

[0047] In the above embodiment and modified example, only the lower limit value of the white luminance B is set by the above (Equation 1) to (Equation 3), but the upper limit value may also be set. This upper limit value is set by multiplying the lower limit value by a predetermined luminance value (for example, several tens to several hundreds of cd / m 2 It may be obtained by adding a certain coefficient (for example, about 1.1 to 1.5) to the lower limit value or by multiplying the lower limit value by a certain coefficient. In the above formulas (1) to (3), "≧" may be replaced with "=" or ">".

[0048] In the above embodiment, the display panel 1 is a liquid crystal display panel, but is not limited thereto and may be an organic EL (Electro-Luminescence) display panel. In the organic EL display panel, the white luminance B (maximum luminance) is set in the same manner as in the above embodiment.

[0049] In the above description, descriptions of well-known technical matters have been omitted as appropriate in order to facilitate understanding of the present disclosure.

[0050] Various embodiments and modifications of the present invention are possible without departing from the broad spirit and scope of the present invention. The above-described embodiments are for the purpose of explaining the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and the scope of the meaning of the invention equivalent thereto are considered to be within the scope of the present invention. [Explanation of symbols]

[0051] 10…In-vehicle display device 1...display panel, 1a...liquid crystal layer, 1b, 1c...glass substrate, 1d, 1e...polarizing plate, 11...display area 2... cover panel, 21... light-transmitting base material, 22... light-shielding layer, 23... light-transmitting design layer 3…Outer case 4…Circuit board 5...Light-transparent adhesive 7...backlight unit, 7a...light source, 12…Icon lighting section 13. Dashboard 31... middle case, 31a... light guide section 41...Light source 60...Control unit 70: luminance setting device, 71: processing unit, 71a: reflectance acquisition unit, 71b: luminance acquisition unit, 71c: luminance setting unit, 72: storage unit, 73: input unit B: White luminance, R: Luminous reflectance, L1-L4: Lines, PG: Operation program, Fd…forward direction, Bd…backward direction, Ld…leftward direction, Rd…rightward direction, Ud…upward direction, Dd…downward direction

Claims

1. a display panel having a display area that displays information by emitting light; a cover panel disposed in front of the display panel, the cover panel transmitting light from the display panel and reflecting external light; The luminous reflectance R of the cover panel in a range corresponding to the display area and the maximum luminance B of the display panel through the cover panel are set to satisfy the following (Equation 1). In-vehicle display device. B (cd / m ２ )≧4500×R+100...(Formula 1)

2. The cover panel includes: a light-transmitting substrate through which light from the display panel passes; a light-transmitting design layer that is formed on a front surface of the light-transmitting substrate close to the viewer or a rear surface of the light-transmitting substrate close to the display panel within a range including the display area as seen from the viewer, and transmits light from the display panel and reflects external light at the luminous reflectance R; The light-transmitting design layer has a wood grain pattern, a metal pattern, a fabric pattern, or a leather pattern that is visible when exposed to external light. The vehicle-mounted display device according to claim 1 .

3. A method for manufacturing the in-vehicle display device according to claim 1 or 2, A reflectance acquisition unit acquires information regarding the luminous reflectance R; A setting unit sets the luminance B that satisfies the above (Formula 1) based on the acquired luminous reflectance R to the in-vehicle display device. A method for manufacturing an in-vehicle display device.

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