JP6354974B2 - Liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal display element.

  As a liquid crystal display element, for example, one disclosed in Patent Document 1 is known. This liquid crystal display element is configured as a segment display type with a limited number of display patterns, a passive drive system, and a so-called normally black (NB) mode liquid crystal display element with a black background color.

JP 2013-178474 A

  By the way, a liquid crystal display element widely used in outdoor applications or the like is usually configured as a transflective type (or a reflective type) that allows a display design to be visually recognized even by reflection of external light. In the liquid crystal display element disclosed in Patent Document 1, in the (NB) mode liquid crystal display element configured with a black background color, the light emitted from the display design formation area out of the external light incident from the background area is the user. Design to display the thickness of the second substrate located on the back side of the liquid crystal layer in order to solve the problem that the display quality is deteriorated due to being visually recognized as a shadow Is substantially the same as the width of the segment shape having the narrowest width among the segment shapes constituting. However, as the width of the segment shape becomes narrower (for example, 0.7 mm or less), there is a problem that external light incidence decreases and a part of the design becomes difficult to see.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display element that reduces shadow appearance and has a good display quality even in a normally black mode.

In order to achieve the above object, a liquid crystal display element according to a first aspect of the present invention is a segment display type, passive drive type, and normally black mode liquid crystal display element that displays a predetermined design on a display surface. And
A liquid crystal layer;
A first substrate located closer to the display surface than the liquid crystal layer;
A second substrate facing the first substrate across the liquid crystal layer;
An electrode that is located on the liquid crystal layer side of each of the first substrate and the second substrate and is provided for displaying the predetermined design;
A reflective layer that is located on a side opposite to the liquid crystal layer side of the second substrate and reflects light incident from the liquid crystal layer side;
A polarizing plate positioned between the second substrate and the reflective layer,
The thickness of the second substrate is 0.7 mm or less ,
The reflectance of the reflective layer including the polarizing plate is the reflectance [%] of the reflective layer including the polarizing plate to the width [mm] of the segment shape having the narrowest width among the segment shapes constituting the design . multiplied values are set to be 20 or more,
The width of the segment shape having the narrowest width among the segment shapes constituting the design is 0.2 to 0.7 mm.
It is characterized by that.

  According to the present invention, it is possible to provide a liquid crystal display element that reduces shadow appearance and has good display quality even in the normally black mode.

It is a schematic sectional drawing of the liquid crystal display element which concerns on 1st Embodiment of this invention. (A) is the figure which showed an example of the design which a liquid crystal display element displays, and the shape which comprises this. (B) is the figure which represented typically the sectional view on the AA line shown to Fig.2 (a) of a liquid crystal display element. It is the figure which showed the microscope picture of the liquid crystal display element in which the damage | wound produced in the board | substrate by the movement of a spacer for demonstrating the function of the spacer which concerns on this embodiment. (A) is the figure which showed the table | surface which put together the relationship between the board thickness of a 2nd board | substrate, and shadow appearance. (B) is the figure which showed the photograph of the display surface of one Example of the liquid crystal display element which concerns on 1st Embodiment. (C) is the figure which showed the photograph of the display surface of the liquid crystal display element which concerns on a comparative example. (A) is the figure which showed the graph of the relationship between a segment width, an external light incident angle, and the board thickness of a 2nd board | substrate. (B) is the figure which showed the table | surface which put together the relationship between the external light incident angle and plate | board thickness of a 2nd board | substrate in case segment width is 0.2 mm. (C) is the figure which showed the table | surface which put together the relationship between the external light incident angle and plate | board thickness of a 2nd board | substrate in case a segment width is 0.4 mm. (A) is the figure which showed the table | surface which put together the relationship between the single-piece | unit reflectance and appearance of a reflection layer containing a 2nd polarizing filter in case a segment width is 0.4 mm. (B) is the figure which showed the table | surface which put together the relationship between the single-piece | unit reflectance and appearance of a reflection layer containing a 2nd polarizing filter in case a segment width is 0.55 mm. (C) is the figure which showed the table | surface which put together the relationship between the single-piece | unit reflectance and appearance of a reflection layer containing a 2nd polarizing filter in case a segment width is 0.7 mm. (D) is the figure which showed the table | surface which put together the relationship between the segment width | variety, the single-piece | unit reflectance of the reflection layer containing the 2nd polarizing filter which can visually recognize a segment, and the value which multiplied these. (A) is a figure for demonstrating the reinforcement member with which the liquid crystal display element which concerns on 2nd Embodiment is provided. (B) is a top view of the reinforcement member which concerns on a modification, and is a figure for demonstrating the relationship between the opening part of a reinforcement member, and the display area of a liquid crystal display element.

An embodiment according to the present invention will be described with reference to the drawings.
In the following description, the display surface direction (direction of the viewer of the liquid crystal display element) of the liquid crystal display element in a predetermined component is “front”, and the opposite direction is “back”.

1. First Embodiment A liquid crystal display element 100 according to the first embodiment shown in FIG. 1 is a normally black (NB) mode segment display type liquid crystal display element with a passive drive method, a black background color, and is outdoors. For example (for example, mounted on a motorcycle such as a motorcycle).
The liquid crystal display element 100 includes a liquid crystal panel 10, a pair of first polarizing filter 20 and second polarizing filter 30, and a reflective layer 40.

  The liquid crystal panel 10 includes a pair of first substrate 1F and second substrate 1R facing each other, first electrode 2F and second electrode 2R formed on inner surfaces (opposing surfaces) facing each other, and these electrodes. The first alignment film 3F and the second alignment film 3R formed so as to cover the first substrate 1F, the sealing material 4 for bonding the first substrate 1F and the second substrate 1R, the first substrate 1F, the second substrate 1R and the seal A liquid crystal layer 5 sealed in a space formed by the material 4 and a spacer 6 for maintaining a constant thickness (cell gap) of the liquid crystal layer 5 are provided.

  Each of the first substrate 1F and the second substrate 1R is a transparent substrate made of, for example, glass or plastic. The first substrate 1F and the second substrate 1R are arranged so as to face each other with the liquid crystal layer 5 interposed therebetween, and their main surfaces are parallel to each other. The first substrate 1F is located on the front side of the liquid crystal panel 10, and the second substrate 1R is located on the back side of the liquid crystal panel 10.

  The plate thickness of the first substrate 1F is set to about 1.1 mm, for example. The plate thickness of the second substrate 1R is set smaller than the plate thickness of the first substrate 1F. Specifically, the plate thickness of the second substrate 1R substantially matches the width of the segment shape having the narrowest width among the segment shapes constituting a predetermined design displayed on the display surface of the liquid crystal display element 100 (just, (Specifically, as an example, it is set so as to substantially match within a range of 0.7 mm or less). Furthermore, the thickness of the second substrate 1R is preferably set so as to satisfy the condition of 0.15 mm or more and 0.4 mm or less. The reason for this setting will be described in detail later.

  The first electrode 2F and the second electrode 2R are each composed of an ITO (Indium Tin Oxide) film or the like mainly composed of indium oxide, and are composed of transparent electrodes that transmit light. The first electrode 2F is formed on the back surface of the first substrate 1F, and the second electrode 2R is formed on the front surface of the second substrate 1R by a known method (sputtering, vapor deposition, etching, etc.). Note that the first electrode 2F and the second electrode 2R may be formed of a material containing a π-conjugated conductive polymer such as polythiophene. Moreover, you may provide the insulating film which covers each of the 1st electrode 2F and the 2nd electrode 2R as needed.

The first electrode 2F is configured as a common electrode, and the second electrode 2R is configured as a segment electrode. A voltage is applied to both electrodes by a passive drive system. That is, the liquid crystal panel 10 is a segment display type and is configured as a passive drive type liquid crystal panel. The first electrode 2F may be configured as a segment electrode, and the second electrode 2R may be configured as a common electrode.
The liquid crystal display element 100 displays a predetermined design representing a symbol (including letters and numbers), a figure, or a combination thereof in a region where both electrodes overlap in the substrate normal direction. Specifically, on a display surface with a black background color, the liquid crystal display element 100 displays a predetermined design in white by guiding light such as external light to a region where an ON voltage is applied to both electrodes ( How to display will be described later).

  An example of the predetermined design displayed on the display surface is shown in FIG. The figure shows an example in which the liquid crystal display element 100 displays the design 50 “km / l” on the display surface. The design 50 includes a segment shape 51 representing the character “k”, a segment shape 52 representing the character “m”, a segment shape 53 representing the symbol “/”, and a segment shape 54 representing the character “l”. It is configured. By the combination of these segment shapes, the viewer can recognize the unit “km / l” by the displayed design 50. Here, the segment shape refers to a shape (independent one shape) surrounded by the background region B.

Returning to FIG. 1, the first alignment film 3 </ b> F and the second alignment film 3 </ b> R are in contact with the liquid crystal layer 5 to define the alignment state of the liquid crystal molecules included in the liquid crystal layer 5. It is formed by a known method (for example, flexographic printing). The first alignment film 3F is formed so as to cover the first electrode 2F from the back side, and the second alignment film 3R is formed so as to cover the second electrode 2R from the front side.
The first alignment film 3F and the second alignment film 3R are rubbed. The rubbing direction of the first alignment film 3F and the rubbing direction of the second alignment film 3R are substantially orthogonal (including just orthogonal). Thus, the alignment directions of the liquid crystal molecules included in the liquid crystal layer 5 are defined by the two alignment films subjected to the rubbing treatment. The alignment treatment applied to the first alignment film 3F and the second alignment film 3R may be other known processes such as a photo-alignment process and a protrusion alignment process.

  The liquid crystal layer 5 is formed by sealing a liquid crystal material in a sealed space formed by the sealing material 4 for joining the pair of first substrate 1F and second substrate 1R and both substrates. The liquid crystal material to be sealed is, for example, a nematic liquid crystal for TN (Twisted Nematic) having a refractive index anisotropy Δn of about 0.09. The liquid crystal molecules of the liquid crystal layer 5 are oriented in the direction of the major axis between the end of the liquid crystal layer 5 on the first substrate 1F side and the second substrate 1R side due to the alignment regulating force of the first alignment film 3F and the second alignment film 3R. While being twisted 90 ° at the end, it is oriented so that it gradually rotates (turns) from one substrate side to the other substrate side (chiral structure). Thus, the liquid crystal layer 5 when no voltage is applied has chirality. As will be described later in the modification, the liquid crystal layer 5 is not limited to the TN liquid crystal, but in the present embodiment, in order to facilitate understanding of the configuration of the liquid crystal display element 100, the liquid crystal display element 100 is The description will be made assuming that the TN type.

The spacer 6 is a fixed spacer that keeps the thickness (cell gap) of the liquid crystal layer 5 constant and is difficult to move even when vibration is applied. The spacer 6 is fixed between the first substrate 1F and the second substrate 1R by heating. In the present embodiment, the cell gap is maintained at about 6.0 μm by the spacer 6. As the fixed spacer, for example, SP-2063AC4 manufactured by Sekisui Fine Chemical Co., Ltd. can be used.
By the way, in a liquid crystal panel, the plate thickness of a pair of substrates is usually set to be the same (for example, both the front side substrate and the back side substrate are about 1.1 mm). However, in the liquid crystal panel 10 according to the present embodiment, as described above, the plate thickness of the second substrate 1R that is the back substrate is set to be smaller than the plate thickness of the first substrate 1F. When the substrate becomes thin in this way, a thread-like flaw (spacer flaw S1) as shown in FIG. 3 is generated in the second substrate 1R due to vibration. In this embodiment, a fixed spacer is used as the spacer 6 in order to reduce or suppress the spacer scratch S1 generated in this way. Thereby, even if the liquid crystal display element 100 is used outdoors (for example, even if it is mounted on a motorcycle such as a motorcycle and is vibrated), the spacer scratch S1 hardly occurs and the display quality can be kept good.
The method for preventing the movement of the spacer is not limited to the method using the fixed spacer. The spacer 6 may be a photo spacer made of a photosensitive resin material or the like.

  The first and second polarizing filters 20 and 30 are polarizing plates that emit light incident from the front side or the back side as linearly polarized light along a transmission axis perpendicular to the absorption axis. The first polarizing filter 20 is disposed on the front side of the first substrate 1F, and the second polarizing filter 30 is disposed on the back side of the second substrate 1R so as to be positioned between the second substrate 1R and the reflective layer 40. The first polarizing filter 20 and the second polarizing filter 30 are arranged so that their optical axes (transmission axis or absorption axis) are substantially parallel to each other (just including parallel) (parallel Nicol arrangement). .

The reflective layer 40 is a semi-reflective layer that reflects light incident from the front side and transmits light from the back side, and is composed of a half mirror made of aluminum or the like, or a material in which a reflective filler is dispersed. The reflective layer 40 may be formed integrally with the second polarizing filter 30 by being directly formed on the back surface of the second polarizing filter 30. The single reflectance of the reflective layer 40 including the second polarizing filter 30 (determined by the transmittance of the second polarizing filter 30 and the reflectance of the reflective layer 40) is a predetermined design displayed on the display surface of the liquid crystal display element 100. Is set in consideration of the width of the segment shape having the narrowest width among the segment shapes constituting the. Specifically, the single-layer reflectance of the reflective layer 40 including the second polarizing filter 30 is such that the reflective layer 40 including the second polarizing filter 30 has the narrowest segment shape width among the segment shapes constituting the design. Is set so that the value obtained by multiplying the single reflectances becomes 20 or more. The single reflectivity of the reflective layer 40 includes the second polarizing filter 30 when the reflective layer 40 is formed integrally with the second polarizing filter 30 as described above. This is because it is difficult to obtain a rate.
The reason for this setting will be described in detail later.

  On the back side of the liquid crystal display element 100 (that is, the back side of the reflective layer 40), a backlight (not shown) is provided. The backlight emits predetermined light in a planar shape to illuminate the liquid crystal display element 100 from the back side, and is configured by, for example, a combination of a light emitting diode and a light guide member. The backlight is used when the liquid crystal display element 100 performs transmissive display. That is, the liquid crystal display element 100 according to the present embodiment is configured as a transflective type (also referred to as a semi-reflective type).

  The liquid crystal display element 100 having the above configuration performs display as follows.

Since the liquid crystal display element 100 according to the present embodiment mainly reduces the shadow appearance when performing reflective display without using the illumination of the backlight, the reflective display will be described here.
(Black display)
In the liquid crystal display element 100, the OFF voltage is set to a value lower than the threshold voltage at which liquid crystal molecules start to behave. Then, even when an OFF voltage is applied, the liquid crystal molecules remain substantially parallel to the substrate surface. That is, the liquid crystal layer 5 remains chiral in the region where the OFF voltage is applied. Accordingly, in this region, external light that is incident from the front side of the liquid crystal display element 100 and is linearly polarized by passing through the first polarizing filter 20 passes through the liquid crystal layer 5 and is about 90% due to the chirality of the liquid crystal layer 5. ° Polarization direction is tilted. Then, the light that has passed through the liquid crystal layer 5 cannot pass through the second polarizing filter 30 whose optical axis is substantially parallel to the first polarizing filter 20. In this way, the liquid crystal display element 100 displays the background in black (NB mode).
(White display)
On the other hand, in the region where the ON voltage is applied, the liquid crystal molecules of the liquid crystal layer 5 are aligned along the voltage application direction (substrate normal direction), and the chirality thereof is lost. The polarization direction of the linearly polarized light that has passed through the liquid crystal layer does not substantially change even when it passes through the liquid crystal layer 5. Therefore, the light that has passed through the liquid crystal layer 5 passes through the second polarizing filter 30 whose optical axis is substantially parallel to the first polarizing filter 20 and is reflected by the reflective layer 40. For the same reason, the light reflected by the reflective layer 40 can pass through the second polarizing filter 30, the liquid crystal layer 5, and the first polarizing filter 20 in this order from the back side of the liquid crystal display element 100. When the reflected light enters the eyes of the viewer, the predetermined design is displayed in white.

(About the thickness of the second substrate 1R)
FIG. 4C shows a liquid crystal display element having the same configuration as the liquid crystal display element 100, and the display surface of the comparative example in which the thicknesses of the first substrate 1F and the second substrate 1R are both set to 1.1 mm. The photograph of is shown.
As can be seen from this photograph, in the setting of the comparative example, the shadow appears as described above (see the segment shadow S2 generated in the segment shape formation region). This shadow appearance is caused by the parallax (the parallax of the thickness of the second substrate 1R) by the second substrate 1R which is the back substrate. In order to reduce the appearance of shadows, the second substrate 1R may be set as thin as possible so that the distance between the liquid crystal layer 5 and the reflective layer 40 is reduced. However, in this case, there is a problem as to what value should be set for the thickness of the second substrate 1R.

  The inventor of the present application sets the thickness of the second substrate 1R to a value in the vicinity of the width of the segment shape having the narrowest width among the segment shapes constituting the predetermined design displayed on the display surface (preferably, It has been conceived that shadow appearance can be effectively reduced by substantially matching the width of the segment shape having the narrowest width (just when matching is included). Usually, in the case of the segment display type, the width of the segment shape having the narrowest width among the segment shapes constituting the predetermined design is set to about 0.4 mm (for example, 0.2 to 0.7 mm). This is because a segment shape thinner than 0.4 mm is difficult to recognize for visual recognition. The inventor of the present application has thought that if the thickness of the second substrate 1R is set to a value of about 0.4 mm, the segment shadow S2 should not occur in the segment shape in the visually recognizable design. .

  Specifically, for example, among the segment shapes 51 to 54 constituting the design 50 as an example of the display design shown in FIG. 2A, the segment shape 53 representing the symbol “/” is the thinnest. Suppose that it has a width D and this width D is 0.4 mm. In this case, the thickness of the second substrate 1R is set to a value in the vicinity of the width D of the segment shape 53 = 0.4 mm. Hereinafter, the width D of the segment shape having the narrowest width among the segment shapes constituting the predetermined design is referred to as a segment width D.

  The inventor of the present application prepares a plurality of second substrates 1R having plate thicknesses of 0.2 mm, 0.4 mm, 0.6 mm, and 0.7 mm, which are values in the vicinity of 0.4 mm, and the second substrates having respective plate thicknesses. The display surface of the liquid crystal display element 100 provided with 1R was visually observed. The observation result is shown in FIG. In addition, the observation result of the comparative example which set 2nd board | substrate 1R to 1.1 mm was also written together in the same figure. In the drawing, the thickness of the second substrate 1R is expressed as “R thickness”.

In Fig.4 (a), the observation result by visual observation was shown using the symbol of (circle), (triangle | delta), and x. The evaluation indicated by each symbol is as follows.

○… Shadow is not visible and looks good △… Shadow is slightly visible but acceptable X… Shadow is conspicuous

As a result of the observation, when the thickness of the second substrate 1R was 0.7 mm and 0.6 mm, although the shadow appearance was slightly visually recognized, the display quality was acceptable and was generally good. In the case of thinner plate thicknesses of 0.4 mm and 0.2 mm, the shadow appearance was almost invisible, and the display quality was better. For reference, FIG. 4B shows a photograph of the display surface when the plate thickness is 0.4 mm. As you can see from this photo, the shadow is almost unrecognizable. On the other hand, as described above, with reference to FIG. 4C, it can be seen that in the comparative example in which the thickness of the second substrate 1R is 1.1 mm, shadows appear and the display design is difficult to read. In FIGS. 4B and 4C, the first substrate 1F is expressed as “F plate”, and the second substrate 1R is expressed as “R plate”.

  As described above, the plate thickness of the second substrate 1R is set to a value in the vicinity of the width of the segment shape having the narrowest width among the segment shapes constituting the predetermined design displayed on the display surface based on the visual observation result. Specifically, it has been found that the shadow appearance can be reduced by setting the thickness of the second substrate 1R to a value of 0.7 mm or less, more preferably 0.4 mm or less.

)
Next, in order to confirm the advantage by setting the thickness of the second substrate 1R as described above, the inventor of the present application confirms the second substrate 1R when the segment width D is 0.2 mm and 0.4 mm, respectively. The relationship between the thickness of the liquid crystal and the incident angle of external light to the liquid crystal display element 100 (equal to the outgoing angle of external light) was considered. FIG. 5A shows a graph regarding this relationship. How this graph was created will be described in detail later.

  In order for the predetermined segment shape to display white, external light incident on the liquid crystal display element 100 from the front side must enter the formation region of the predetermined segment shape, be reflected by the reflective layer 40, and be emitted from the formation region. I must. Hereinafter, a specific example will be described with reference to FIG.

  2B is a cross-sectional view (AA cross-sectional view) when the liquid crystal display element 100 is cut along the segment width D direction of the segment shape 53 shown in FIG. 2A when an ON voltage is applied. It is shown schematically. In the drawing, in order to facilitate understanding of the incident angle (or emission angle) of external light, configurations other than the first substrate 1F, the second substrate 1R, the liquid crystal layer 5, and the reflective layer 40 are omitted. In addition, hatching indicating a cross section is omitted. A portion denoted by reference numeral 5W is a portion of the liquid crystal layer 5 that makes the display surface display white, and this is referred to as a segment formation region 5W. The other part of the liquid crystal layer 5 (that is, the part of the liquid crystal layer 5 that makes the display surface display black) is denoted by reference numeral 5B. In the figure, external light L is incident on the segment formation region 5W, is reflected by the reflective layer 40, and is emitted from the formation region. When the external light L advances in such an optical path, the segment shape 53 representing “/” is visually recognized by the viewer as white display.

Here, in order to consider the relationship between the external light incident angle θ1 on the display surface of the liquid crystal display element 100 and the thickness T of the second substrate 1R, the liquid crystal panel 10 and the first polarizing filter 20 on the front side have the same refractive index. It is assumed (the refractive index of the glass substrate is 1.6. This refractive index is n2 (n2 = 1.6)), and the thickness other than the second substrate 1R is ignored. In this case, the external light incident angle θ1 is at the interface between the outside (air having a refractive index n1 = 1.0) and the display surface (in the above-described assumption, the interface between the substance having the refractive index n1 and the substance having the refractive index n2). the closer to the Brewster angle theta _B, the reflection loss is reduced (i.e., reflection efficiency superior) for external light incident angle θ1 is supposed to be possible whether a guideline be displayed brightly segment-shaped 53 It is.

Based on the above assumption, if the incident angle to the liquid crystal layer 5 is θ2, the external light reflection angle θ1 can be expressed by the following equation (1).

Also, assuming that the thickness of the second substrate 1R is T under the above assumption, θ2 can be expressed by the following equation (2).

Further, based on the above assumption, the Brewster angle θ _B can be expressed by the following equation (3).
When the Brewster angle θ _B is calculated by the equation (3), it is about 58 ° in degrees.

When the segment width D is set to 0.2 mm and 0.4 mm and the plate thickness T of the second substrate 1R is appropriately changed within the range of 0.15 to 1.1 mm according to the above formulas (1) and (2) FIG. 5A is a graph created by determining the relationship between the plate thickness T and the external light incident angle θ1. FIG. 5B shows the relationship between T and θ1 when D = 0.2 mm, and FIG. 5C shows the relationship between T and θ1 when D = 0.4 mm. When θ1 exceeds θ _B = 58 °, the light is totally reflected on the surface of the display surface and the reflectance is saturated, so that the reflectance becomes the same value. Further, if the plate thickness T is smaller than 0.15 mm, there is a problem in strength, so the minimum value of the plate thickness T is set to 0.15 mm.

Referring to FIGS. 5A to 5C, when the segment width D is 0.2 mm, the plate thickness T is set to 0.15 mm and 0.2 mm which are values in the vicinity of the segment width D. In addition, it can be seen that the external light incident angle θ1 becomes a value in the vicinity of the Brewster angle θ _B = 58 ° (θ1 = 63, 45). When the segment width D is 0.4 mm, when the plate thickness T is set to 0.3 mm and 0.4 mm, which are values in the vicinity of the segment width D, the external light incident angle θ1 becomes the Brewster angle θ _B It can be seen that the value is around 58 ° (θ1 = 63, 45).
Further, in any case where the segment width D is 0.2 mm or 0.4 mm, the outside light increases as the plate thickness T becomes 0.7 mm, 0.4 mm, 0.3 mm or less than 1.1 mm. It can be seen that the incident angle θ1 approaches the Brewster angle θ _B = 58 °, and the reflection loss decreases.

From the above consideration, it can be seen that if the thickness T of the second substrate 1R is set to a value in the vicinity of the segment width D, the reflection loss is small and the segment shape (or display design) can be displayed with good brightness.
That is, the plate thickness of the second substrate 1R is set so as to substantially match (1) the segment width D (for example, the plate thickness of the second substrate 1R is approximately equal to or less than 0.7 mm), or (2 More preferably, if the thickness is set to 0.15 mm or more and 0.4 mm or less, not only the shadow appearance can be reduced, but also the segment shape can be displayed with good brightness.

(Single reflectance of the reflective layer 40 including the second polarizing filter 30)
As described above, in order for the predetermined segment shape to display white, external light incident on the liquid crystal display element 100 from the front side enters the formation region of the predetermined segment shape, is reflected by the reflective layer 40, and is formed in the same manner. It must be emitted from the area (see FIG. 2 (b)). However, when the width of the segment shape is narrowed, the external light incident on the segment shape is also reduced, and the segment shape constituting the design becomes difficult to see and display quality is deteriorated. This is most remarkable in the segment shape having the narrowest width among the segment shapes constituting the design.

The inventor of the present application sets the second polarizing filter 30 to the width (segment width D) of the segment shape having the narrowest width among the segment shapes constituting the design with respect to the single reflectance of the reflective layer 40 including the second polarizing filter 30. It came to mind that the value obtained by multiplying the single reflection factor of the reflective layer 40 including it was set to 20 or more. That is, the single reflectance of the reflective layer 40 including the second polarizing filter 30 is set to the segment width D as dmm (d ≦ 0.7), and the single reflectance of the reflective layer 40 including the second polarizing filter 30 is set. Is f%,
d × f ≧ 20
As a result, it has been thought that the segment 53 having the segment width D can be made visible.

  The inventor of the present application has three liquid crystals having a segment width D value dmm of 0.4 mm (d = 0.4), 0.55 mm (d = 0.55), and 0.7 mm (d = 0.7), respectively. For the display element 100, the single reflectance value f% including the second polarizing filter 30 is 20% (f = 20), 30% (f = 30), 40% (f = 40), 50% (f = 50). ), 60% (f = 60), 80% (f = 80), a plurality of reflective layers 40 in which the second polarizing filter 30 is integrally formed, and a single reflectance value including the second polarizing filter 30 The display surface of the liquid crystal display element 100 including the reflective layer 40 having f% of 40% is visually observed, and further, the reflective layer together with the second polarizing filter 30 until the segment 53 having the segment width D is dark and cannot be visually recognized. 40 is replaced, and the second polarizing filter 30 is sequentially formed. The reflective layer 40 including the second polarizing filter 30 is sequentially replaced with the second polarizing filter 30 until the segment 53 is lowered and the segment layer 53 is substantially visible. The display surface of the liquid crystal display element 100 was visually observed by increasing the single reflectance value f% of the reflective layer 40. The plate thickness of the second substrate 1R was matched with the segment width D. The observation results are shown in FIGS. 6 (a), (b), and (c). In the figure, the segment width D is “the finest design width”, the plate thickness of the second substrate 1R is “R plate thickness”, and the single reflectance of the reflective layer 40 including the second polarizing filter 30 is “single reflectivity”. ".

In FIG. 6 (a), (b), (c), the observation result by visual observation was shown using the symbol of (circle), (triangle | delta), and x. The evaluation indicated by each symbol is as follows.

○… Visible △… Dark but visible ×… Dark and not visible

As a result of observation, in the liquid crystal display element 100 in which the value d of the segment width D is 0.4 mm, as shown in FIG. 6A, the single-reflectance value f of the reflective layer 40 including the second polarizing filter 30 is obtained. Is 53%, the segment 53 having the segment width D is dark and cannot be visually recognized. In the cases of 50% and 60%, the segment 53 is slightly dark but can be visually recognized. Was generally well visible. Moreover, in the liquid crystal display element 100 in which the value d of the segment width D is 0.55 mm, as shown in FIG. 6B, the single reflectance value f of the reflective layer 40 including the second polarizing filter 30 is 30. %, The segment 53 having the segment width D is dark and cannot be visually recognized. In the case of 40%, the segment 53 is slightly dark but visible, and in the case of 50% and 60%, the segment 53 is almost Visible well. Further, in the liquid crystal display element 100 in which the segment width D value d is 0.7 mm, as shown in FIG. 6B, the single reflectance value f of the reflective layer 40 including the second polarizing filter 30 is 20. %, The segment 53 is dark and cannot be visually recognized. In the cases of 30% and 40%, the segment 53 is slightly dark, but can be visually recognized. In the case of 50%, the segment 53 is generally visually recognized. . FIG. 6D shows the relationship between the value dmm of the segment width D and the single reflectance value f% of the reflective layer 40 including the second polarizing filter 30 in which the segment 53 is visible. According to this, in the liquid crystal display element 100 in which the value d of the segment width D is 0.4 mm, the segment 53 can be visually recognized when d × f ≧ 20, and the value d of the segment width D is 0.55 mm. In the liquid crystal display element 100, the segment 53 is visible when d × f ≧ 22, and in the liquid crystal display element 100 where the value d of the segment width D is 0.7 mm, the segment 53 is satisfied when d × f ≧ 21. Was found to be visible. That is, the relationship between the value dmm of the segment width D and the value f% of the single reflectance of the reflective layer 40 including the second polarizing filter 30 at which the segment 53 cannot be visually recognized is as follows. Considering that d × f = 16, 16.5, and 14 in the liquid crystal display element 100 of 55 mm and 0.7 mm, respectively, and the influence of the difference in the single unit reflectance of several percent on the appearance is slight. Then, the single reflectance of the reflective layer 40 including the second polarizing filter 30 is set to the value of the segment width D as dmm (d ≦ 0.7), and the single reflectance value of the reflective layer 40 including the second polarizing filter 30 is set. Is f%,
d × f ≧ 20 (more desirably d × f ≧ 22)
It can be said that the segment 53 having the segment width D can be made visible.
In addition, the reflectance in the above description is measured by a method (20 ° incidence / 0 ° measurement) using a ring light source and using a reflection colorimeter (manufactured by Yokogawa Meter & Instruments) (standard white plate) (Reflectance when the reflectance is 100%).

2. Second Embodiment A liquid crystal display element according to a second embodiment is a liquid crystal display element 200 shown in FIG. 7A, further including a reinforcing member 60 in addition to the liquid crystal display element 100 according to the first embodiment. . That is, the liquid crystal display element 200 according to the second embodiment includes the liquid crystal panel 10, the pair of first polarizing filter 20 and second polarizing filter 30, the reflective layer 40, and the reinforcing member 60.

  The reinforcing member 60 is mainly for suppressing the second substrate 1R from being bent, and is disposed on the back side of the reflective layer 40 (for example, fixed to the back surface of the reflective layer 40). The reinforcing member 60 is a light-transmitting plate-like transparent reinforcing plate, and is made of a predetermined resin such as acrylic. As described above, when the reinforcing member 60 is provided, the liquid crystal layer 5 and the reflective layer 40 are provided while compensating for a decrease in strength of the second substrate 1R caused by making the second substrate 1R thinner than the first substrate 1F. Therefore, the effect of reducing shadow appearance can be maintained. Such a liquid crystal display element 200 is accommodated in, for example, a metal casing made of aluminum or the like (not shown), and an elastic member made of rubber, elastomer or the like is provided in a casing 90 of a predetermined external device (for example, a motorcycle display instrument). If it is attached so as to be sandwiched via 91, the vibration-resistant spacer 6, the reinforcing member 60, and the elastic member 91 affect the liquid crystal display element 200 by vibration (occurrence of spacer scratches S1, occurrence of the second substrate 1R). Damage, etc.) can be suppressed as much as possible, and a highly reliable product can be provided.

(Modification of reinforcement member)
The reinforcing member may not be transparent as described above. An example of such a reinforcing member 60 'is shown in FIG. The reinforcing member 60 ′ is similarly disposed on the back side of the reflective layer 40. The reinforcing member 60 ′ is a plate-like member having an opening H so as not to overlap the display area 101a, which is a region on the display surface where a predetermined design is displayed, in the normal direction of the display surface. The reinforcing member 60 ′ is made of, for example, elastic resin, metal, or the like. Such a reinforcing member may be used. Further, the reinforcing members 60 and 60 ′ may be provided in combination. For example, both may be provided on the back side of the reflective layer 40. Alternatively, the transparent reinforcing member 60 may be disposed on the front side of the first polarizing filter 20, and the reinforcing member 60 ′ having the opening H may be disposed on the back side of the reflective layer 40. In this case, if the surface of the transparent reinforcing member 60 is subjected to, for example, a non-glare process, the reinforcing member 60 has both a reinforcing function and a function of suppressing external light from being reflected and making the display surface difficult to see. .

  As described above, according to the liquid crystal display elements 100 and 200, it is possible to provide a liquid crystal display element with reduced shadow appearance and good display quality even in the normally black mode. This is realized by the following configuration.

  The liquid crystal display elements 100 and 200 are segment display type, passive drive type, and normally black mode liquid crystal display elements that display a predetermined design on the display surface. Positioned on the liquid crystal layer 5 side of each of the first substrate 1F located on the surface side, the second substrate 1R facing the first substrate 1F across the liquid crystal layer 5, and the first substrate 1F and the second substrate 1R. The electrodes (first electrode 2F, second electrode 2R) provided for displaying the predetermined design and the liquid crystal layer 5 side opposite to the second substrate 1R are incident from the liquid crystal layer 5 side. And a second polarizing filter 30 positioned between the second substrate 1 </ b> R and the reflective layer 40. The thickness T of the second substrate 1R substantially matches the width of the segment shape having the narrowest width among the segment shapes constituting the design. Note that if the thickness T of the second substrate 1R is 0.7 mm or less, more preferably 0.15 mm or more and 0.4 mm or less, it is possible to further reduce the shadow appearance, and the segment with good brightness. The shape can be displayed. The thickness of the second substrate 1R is smaller than the thickness of the first substrate 1F.

  In addition, the liquid crystal display elements 100 and 200 have a segment shape width (dmm) in which the single reflectance (f%) of the reflective layer 40 including the second polarizing filter 30 is the narrowest among the segment shapes constituting the design. ) Multiplied by the single reflectance (f%) of the reflective layer 40 including the second polarizing filter 30 is 20 or more (d × f ≧ 20), more preferably 22 or more (d × f ≧). 22). Accordingly, as described above, the segment shape having the narrowest width among the segment shapes constituting the design can be visually recognized, and thus a liquid crystal display element having a good display quality can be provided.

  In the above description, the liquid crystal display element 100 has been described as a TN type, but is not limited thereto. The liquid crystal display element 100 may be an NB mode VA (Vertical Alignment) type or STN (Super-Twisted Nematic) type liquid crystal display element.

  In the above description, the liquid crystal display element 100 is configured as a transflective type (semi-reflective type), but may be configured as a reflective type without providing a backlight. In this case, since the reflection layer 40 does not need to transmit light from the back side, the reflection layer 40 does not need to be a semi-reflection layer such as a half mirror, and may be a reflection plate such as a mirror.

  In addition, this invention is not limited by said embodiment, a modification, and drawing. Of course, changes (including deletion of components) can be added to these. Moreover, in the above description, in order to make an understanding of this invention easy, description of the unimportant well-known technical matter was abbreviate | omitted suitably.

  The present invention is suitable for a so-called normally black (NB) mode liquid crystal display element having a segment display type, a passive drive system, and a black background color.

DESCRIPTION OF SYMBOLS 100 ... Liquid crystal display element 10 ... Liquid crystal panel 1F ... 1st board | substrate 1R ... 2nd board | substrate 2F ... 1st electrode 2R ... 2nd electrode 3F ... 1st orientation film 3R ... 2nd orientation film 4 ... Sealing material 5 ... Liquid crystal layer 6 ... Spacer 20 ... First polarizing filter 30 ... Second polarizing filter 40 ... Reflective layer 50 ... Example of design 51-54 ... Example of segment shape 200 ... Liquid crystal display elements 60, 60 '... Reinforcing member

Claims (2)

A segment display type that displays a predetermined design on the display surface, a passive drive method, and a normally black mode liquid crystal display element,
A liquid crystal layer;
A first substrate located closer to the display surface than the liquid crystal layer;
A second substrate facing the first substrate across the liquid crystal layer;
An electrode that is located on the liquid crystal layer side of each of the first substrate and the second substrate and is provided for displaying the predetermined design;
A reflective layer that is located on a side opposite to the liquid crystal layer side of the second substrate and reflects light incident from the liquid crystal layer side;
A polarizing plate positioned between the second substrate and the reflective layer,
The thickness of the second substrate is 0.7 mm or less ,
The reflectance of the reflective layer including the polarizing plate is the reflectance [%] of the reflective layer including the polarizing plate to the width [mm] of the segment shape having the narrowest width among the segment shapes constituting the design . multiplied values are set to be 20 or more,
The width of the segment shape having the narrowest width among the segment shapes constituting the design is 0.2 to 0.7 mm.
The liquid crystal display element characterized by the above-mentioned. The reflectance of the reflective layer including the polarizing plate is the reflectance [%] of the reflective layer including the polarizing plate to the width [mm] of the segment shape having the narrowest width among the segment shapes constituting the design . The multiplication value is set to be 22 or more.
The liquid crystal display element according to claim 1.