JP3412520B2 - Electronic clock - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic timepiece such as a wristwatch or a stopwatch that counts and displays time. In particular, it relates to a semi-transmissive reflective electronic timepiece capable of multicolor display.

[0002]

2. Description of the Related Art Conventionally, as the display element, a transflective liquid crystal display element made of liquid crystal has been known. This liquid crystal display element is configured by using a transmission polarization axis variable optical element capable of changing the transmission polarization axis, such as TN (Twisted Nematic) liquid crystal and STN (Super-Twisted Nematic) liquid crystal. Specifically, this transmission polarization axis variable optical element is sandwiched between two polarizing plates, and a semi-transmission type reflection plate and a light source are sequentially arranged on the surface of the liquid crystal display element opposite to the viewer side. This liquid crystal display element is used as a reflective display element where there is external light such as outdoors, and is used as a transmissive display element by turning on a light source when there is little external light.

However, the transflective liquid crystal display device having the above-mentioned structure has a problem that the display becomes darker during the reflective display as compared with the reflective liquid crystal display device having no transmissive function. It was The reason is that the reflector used in the conventional transflective liquid crystal display element is
In order to secure the light transmission, it is formed by using Al (aluminum) or the like having a very thin thickness, or is formed including an opening portion, so that the brightness at the time of reflective display is sacrificed. It is due to Further, in the conventional transflective liquid crystal display element, it is difficult to perform multi-color display in both reflective display and transmissive display.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in a transflective display element, a very bright display is provided when a reflective display is performed. It is an object of the present invention to enable multi-color display at the same time in both the reflective type and the transmissive type.

[0005]

(1) In order to achieve the above-mentioned object, an electronic timepiece according to the present invention comprises: (a) transmission polarization axis varying means capable of changing the transmission polarization axis; b2) a first polarized light separating means and a second polarized light separating means arranged on both sides of the transparent polarized light axis varying means, and (c) a transparent polarized light axis varying means sandwiching the second polarized light separating means. An electronic timepiece having a light source arranged on the opposite side, wherein (d) the first polarized light separating means transmits all wavelength components in the visible light region with respect to the linearly polarized light component in the first direction, and With respect to the linearly polarized light component in the second direction orthogonal to the one direction, it has a function of transmitting all the specific wavelength components in the visible light region but not the other wavelength components, (e) the second polarized light separating means, Transmit the linearly polarized light component in the third direction It has a function of reflecting linearly polarized light component in the direction perpendicular to the third direction together, and (f) the light source to emit colored light, wherein said polarization changing means
An optical element is provided between the light source and the optical element,
The light from the second polarized light separating means side is absorbed and
Light emitted from the light source is transmitted toward the second polarized light separating means side.
The visible light to attenuate the externally reflected light from the light source.
The light absorber that absorbs light in almost the entire wavelength range
It is characterized in that an opening is formed to transmit the light .

According to the electronic timepiece having the above structure, the light incident from the outside of the first polarization separation means is reflected from the second polarization separation means according to the state of the transmission polarization axis of the transmission polarization axis varying means. Two display states are obtained, a first display state by light and a second display state by light reflected from the second polarized light separating means only for a specific wavelength component, and as a result, a reflective multicolor display is obtained. Will be realized.

The first display state and the second display state are not realized based on the absorption of light,
Since it is realized by the light reflected from the second polarized light separating means, their display state becomes an extremely bright display. For example, the first polarized light separating means transmits all wavelength components in the visible light range for the linearly polarized light component in the first direction and is visible for the linearly polarized light component orthogonal to the first direction (in the second direction). Since only the specific wavelength component of the light region is transmitted, bright white display can be performed in the first display state, while bright colored display can be performed in the second display state.

With respect to the color light from the light source, the third display state by the color light of the light source transmitted through the first polarization separation means and the first polarization separation means according to the state of the transmission polarization axis of the transmission polarization axis varying means. Two display states, that is, a fourth display state in which light is not transmitted (or a state in which only a predetermined wavelength range is transmitted) are obtained, and as a result, transmissive multi-color display is realized.

In addition to the above four display states, halftone display is possible according to the state of the transmission polarization axis of the transmission polarization axis varying means. Further, it is desirable that the coloring of the first polarized light separating means and the tint of the colored light of the light source be different from each other.
This is because the number of display colors can be increased.

In the above configuration, the configuration requirement (d)
From a different point of view, the first polarized light separating means opposes a linearly polarized light component in a predetermined first direction of the light incident from the first side of the first polarized light separating means to the first side. The first of the lights that are transmitted as linearly polarized light in the first direction to the second side and are incident from the first side of the first polarization splitting means.
Of the linearly polarized light component in the second direction orthogonal to the direction, only the specific wavelength component is transmitted to the second side, and the linearly polarized light component in the first direction out of the light incident from the second side of the first polarization splitting means is transmitted. Only the specific wavelength component of the linearly polarized light component in the second direction of the light incident from the second side of the first polarization separation means is transmitted to the first side as linearly polarized light in the first direction. It is considered to be a polarized light separating means for transmitting the light to.

From a different point of view of the constitutional requirement (e), the second polarized light separating means is a linearly polarized light component in a predetermined third direction of the light incident from the transmission polarization axis varying means side. A fourth light source that transmits the light source side and is orthogonal to the third direction.
Direction linearly polarized light component is reflected to the transmission polarization axis varying means side, and the polarization splitting means capable of emitting linearly polarized light in the third direction to the transmission polarization axis varying means side with respect to the light incident from the light source side. It is believed that there is.

(2) Next, another electronic timepiece according to the present invention is the electronic timepiece according to (1), further including: (g) at least one optical element between the transmission polarization axis varying means and the light source. It is characterized by having two.

According to such an electronic timepiece, various improvements can be added to the display state of the electronic timepiece by the action of the optical element. It should be noted that the optical element includes the transmission polarization axis changing means and the second polarization separating means, the second polarization separating means and the light source, the transmission polarization axis changing means and the second polarization separating means, and the second polarization separating means. It can be provided on both sides between the light sources.

Further, in such an electronic timepiece, the optical element may be a light scatterer. This makes it possible to cause depolarization of the light transmitted through the second polarized light separating means by using the light scatterer with respect to the second display state by the light of the specific wavelength component. It is possible to suppress reflection of light of all wavelength components to the transmission polarization axis varying means side. As a result, it is possible to suppress color mixture between all wavelength component light transmitted through the second polarized light separating means and the specific wavelength component light reflected by the second polarized light separating means, and thus display with high color purity can be obtained. it can.

In such an electronic timepiece, the optical element may be a gray semi-transmissive light absorbing / scattering body. In this way, with respect to the second display state by the light of the specific wavelength component, it is possible to cause depolarization of the light transmitted through the second polarization splitting means by using the light absorbing scatterer in the gray semi-transmission state. It is possible to suppress the reflection from the second polarization splitting means to the transmission polarization axis varying means side. Furthermore, since the optical element of this embodiment is also a light absorber, it is possible to suppress reflection by absorbing light. As a result, it is possible to suppress color mixing between the light transmitted through the second polarized light separating means and the light in the specific wavelength range reflected by the second polarized light separating means, thus obtaining a display with higher color purity. You can

When a light-absorbing scatterer is used as the optical element as described above, the light-absorbing scatterer has a light transmittance of 10% or more and 80% or less with respect to light in almost the entire wavelength range of the visible light region, especially. It is desirable that the light transmittance is 50% or more and 70% or less.

When the optical element is provided only between the second polarization separation means and the light source, the optical element absorbs the light from the second polarization separation means side, and at the same time, absorbs the light from the light source from the second polarization separation means side. The optical element can have a function of transmitting light to. With this configuration, in the second display state by the light of the specific wavelength component, the light transmitted through the second polarized light separating means can be absorbed by the light absorber and the reflection to the transmission polarization axis varying means side can be suppressed. As a result, it is possible to suppress color mixing between the light that has passed through the second polarized light separation means and the light that has been reflected by the second polarized light separation means and that has a specific wavelength range, and thus display with high color purity can be obtained.

The above-mentioned "optical element having a function of absorbing the light from the second polarized light separating means side and transmitting the light from the light source to the second polarized light separating means side" is, for example, a visible light region. Can be formed by forming an opening for transmitting light in a light absorber that absorbs light in almost all wavelength ranges. With this configuration, regarding the second display state by the light of the specific wavelength component, the light transmitted through the second polarization separation means is absorbed by the light absorber that absorbs the light in almost the entire wavelength range of the visible light region, and the transmitted polarized light is obtained. It is possible to suppress the reflection toward the axis changing means side. As a result, it is possible to suppress color mixing between the light that has passed through the second polarized light separation means and the light that has been reflected by the second polarized light separation means and that has a specific wavelength range, and thus display with high color purity can be obtained.

The area ratio of the opening to the optical element is preferably 5 to 30%. Further, by setting the distance between the optical element and the light source to be equal to or larger than the diameter of the opening, it is possible to reduce the amount of light transmitted through the optical element during reflective display and reflected back by the light source. As a result, color mixing of light can be suppressed.

The optical element may be a polarizing plate whose transmission axis is offset with respect to the second polarized light separating means. In this way, regarding the second display state by the light of the specific wavelength component,
The light transmitted through the second polarization separation means can be absorbed by the polarizing plate whose transmission polarization axis is deviated with respect to the second polarization separation means, and reflection to the transmission polarization axis varying means side can be suppressed. As a result, it is possible to suppress color mixing between the light that has passed through the second polarized light separation means and the light that has been reflected by the second polarized light separation means and that has a specific wavelength range, and thus display with high color purity can be obtained.

With respect to all of the electronic timepieces of various configurations described above, the light sources may be configured to emit light of two or more colors from different portions. By doing so, it is possible to display two or more colors corresponding to the colored portion of the light source during transmissive display.

The above-mentioned "light source for emitting light of two or more colors from different portions" is, for example, a light guide plate divided into at least two or more, and LEDs provided corresponding to each of the light guide plates. It may be configured to include a (light emitting diode) element. According to this configuration, at the time of transmissive display, two or more colors can be displayed on the display unit corresponding to the light guide plate in which the light source is divided. In addition, the LED element consumes less power and is easy to be colored, so that it is particularly effective when it is used in a mobile device.

The above-mentioned "light source that emits light of two or more colors from different portions" may include, for example, a plurality of LED elements that emit different colors. With this configuration, it is possible to display two or more colors in the display unit corresponding to the LED element that emits different colors during the transmissive display. L
As described above, the ED element has low power consumption and is easy to be colored.

The above-mentioned "light source which emits light of two or more colors from different portions" may include, for example, an EL (electroluminescence) element having a coloring region of at least two or more colors. With this configuration, it is possible to display two or more colors in the display unit corresponding to the EL element that emits different colors during the transmissive display. Similar to the LED element, the EL element has low power consumption and is easy to be colored, and thus is particularly effective when it is used in a portable device.

As the above-mentioned "light source which emits light of two or more colors from different portions", for example, a plurality of EL (electroluminescence) elements which emit different colors may be used. With this configuration, it is possible to display two or more colors in the display unit corresponding to the EL element that emits different colors during the transmissive display. As described above, the EL element has low power consumption and is easy to be colored.

The above-mentioned "light source that emits light of two or more colors from different portions" is, for example, at least one LED.
An element and at least one EL (electroluminescence) element may be used. According to this configuration, it is possible to display two or more colors in the display section corresponding to the LED element and the EL element during the transmissive display. As described above, both the LED element and the EL element have low power consumption and are easy to be colored.

[0027]

[0028]

With respect to the light from the light source, the colored light transmitted through the optical element which is the colored layer and colored, and then transmitted through the first polarization separation means in accordance with the state of the transmission polarization axis of the transmission polarization axis varying means. And a fourth display state in which light does not pass through the first polarized light separating means (or a state in which only a predetermined wavelength range is transmitted) through the first polarized light separating means. A multi-color display of the mold is realized.

A halftone display is possible according to the state of the transmission polarization axis of the transmission polarization axis varying means, and the display color is made different by making the coloring of the first polarization separating means different from the tint of the colored light of the light source. The fact that the number can be increased is as described above.

Further, according to the present invention, regarding the second display state using the light of the specific wavelength component, the light transmitted through the second polarization separation means is reflected to the transmission polarization axis varying means side, that is, the coloring layer, It is possible to suppress by using an optical element, and thus it is possible to suppress color mixture between the light transmitted through the second polarized light separating means and the light in the specific wavelength range reflected by the second polarized light separating means, and thus the color purity is improved. You can get a high display of.

[0032]

[0033]

Further, according to the present invention, regarding the second display state using the light of the specific wavelength component, the light transmitted through the second polarized light separating means is depolarized by using the gray light scattering absorber and the coloring layer. Also, light absorption is performed, and thus the light is suppressed from being reflected to the transmission polarization axis varying means side. As a result, it is possible to suppress color mixture between the light transmitted through the second polarized light separating means and the light in the specific wavelength range reflected by the second polarized light separating means, and thus it is possible to obtain a display with high color purity.

[0035]

[0036]

Further, according to the present invention, with respect to the second display state using the light of the specific wavelength component, for the light transmitted through the second polarized light separating means, the light absorber having the opening and the coloring layer are used. By absorbing the light, it is possible to prevent the light from being reflected to the transmission polarization axis varying means side, and as a result, the light transmitted through the second polarization separating means and the specific wavelength reflected by the second polarization separating means. Color mixing with the light in the region can be suppressed, and thus display with high color purity can be obtained.

[0038]

[0039]

Further, according to the present invention, regarding the second display state using the light of the specific wavelength component, the light transmitted through the second polarized light separating means is absorbed by the above polarizing plate and the coloring layer. By doing so, it is possible to prevent the light from being reflected to the transmission polarization axis varying means side, and as a result, the second
Color mixing can be suppressed between the light transmitted through the polarized light separating means and the light in the specific wavelength range reflected by the second polarized light separating means, and thus display with high color purity can be obtained.

[0041]

[0042]

Further, according to the present invention, since the optical element is the colored layer and further includes the specular reflection plate, it is colored by the colored layer in the second display state using the light of the specific wavelength component. The reflected light can be reflected toward the transmission polarization axis varying means.

In the electronic timepiece described above, regarding the electronic timepiece in which the colored layer is used, the colored layer can be colored with two or more partially different colors. By doing so, it is possible to display two or more colors corresponding to the colored portion of the colored layer during the transmissive display.

In the electronic timepiece described above, the light source can be colored in addition to the colored layer in the electronic timepiece in which the colored layer is used. This makes it possible to display two or more colors corresponding to the colored portion of the colored layer and the colored light source during transmissive display. Further, for example, a red light source having high color purity can be created by combining a light source emitting pink light and a red filter layer.

In the above electronic timepiece, in the electronic timepiece of the present invention using the first polarized light separating means, the first polarized light separating means can be constituted by a color polarizing plate. By doing so, multi-color display can be realized at low cost. As shown in FIG. 4.60 on page 271 of the Liquid Crystal Device Handbook (Japan Society for the Promotion of Science, 142 Committee, Nikkan Kogyo Shimbun), this color polarizing plate contains all visible light for the polarization component in the first direction. Transmits light in the wavelength range,
As for the polarized light component in the second direction orthogonal to the direction, it has a characteristic of transmitting a specific wavelength region component of the visible light region but not transmitting other wavelength components.

For example, Liquid Crystal Device Handbook, 27
On page 1, Fig. 4.60, the characteristic diagram on the left shows no absorption for light of the red wavelength, the characteristic diagram in the center does not have absorption for the green wavelength, and the characteristic diagram on the right shows blue. It is a color polarizing plate having no absorption for light of the wavelength. These color polarizers are generally red color polarizers,
It is called a green color polarizing plate and a blue color polarizing plate.

In the present invention, a blue color polarizing plate and a purple color polarizing plate are used.

In the electronic timepiece described above, in the electronic timepiece having the structure in which the color polarization plate is used as the first polarized light separating means, the color polarization plates may be at least two different colors. By doing so, it is possible to perform multi-color display corresponding to each color polarizing plate. Further, the color polarizing plate and the neutral polarizing plate may be combined.

Regarding the electronic timepiece of the present invention using the variable transmission polarization axis means in the above electronic timepiece, the variable transmission polarization axis means may be constituted by a liquid crystal element. This makes it possible to obtain a low-cost, high-contrast switching element. A liquid crystal element is preferably used as the transmission polarization axis varying means, and particularly preferably T
An N (Twisted Nematic) liquid crystal element, an STN liquid crystal element or an ECB (Electrically Controlled Birefringence) liquid crystal element is used. In addition, this STN liquid crystal element,
F-STN (Film Compensated Super-Twisted Nemati
c) STN liquid crystal elements using an optically anisotropic body for color compensation such as liquid crystal elements are also included.

In the electronic timepiece described above, the electronic timepiece according to the present invention having a structure using a light source may further include a condensing means for condensing the light from the light source toward the front of the optical element. . This makes it possible to make the display by the transmitted light from the light source bright and easy to see.

Further, as the light source, a surface emitting type EL element can be used. In this case, the EL element has a light green color and the color polarizing plate has a purple color.
In the case of color, the difference in color is noticeable, which is preferable.

As the light source, a surface emitting LED is used.
Alternatively, a light guide plate and a sidelight type LED placed beside it can be used. In this case, when the LED is red,
It is preferable to use blue for the color polarizing plate because the difference in color is noticeable. In this case, when the LED is green,
When the color polarizing plate is purple, the difference in color is noticeable,
preferable.

In the electronic timepiece described above, the surface color of the light source can be darkened in the electronic timepiece according to the present invention having a structure using a light source. By doing so, reflection on the surface of the light source can be suppressed, and as a result, the amount of light transmitted through the optical element that is reflected by the light source and returns again can be reduced, and therefore, reduction in contrast can be prevented. .

In the above electronic timepiece, the electronic timepiece according to the present invention having the structure using the transmission polarization axis varying means and the second polarization separating means is provided between the transmission polarization axis varying means and the second polarization separating means. Light diffusing means may be provided. In this case, the first display state displayed when the external light is reflected by the second polarized light separating means can be a white display due to scattering, and as a result, a high viewing angle can be obtained.

[0056]

[0057]

[0058]

In this electronic timepiece, for example, a light scatterer, a gray semi-transmissive light absorbing scatterer, or the like is provided as an optical element. Therefore, the function of these optical elements improves various display states of the display element. Can be added.

[0060]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) FIG. 1 shows an embodiment of a display device according to the present invention. This display element can perform reflective multi-color display utilizing reflection of external light when there is external light, and on the other hand, transmissive multi-color display using light from a light source even when there is no external light. Color display is possible. That is,
This display element is a reflective display element having a so-called semi-transmissive function. In addition, this display element is configured using liquid crystal, that is, a liquid crystal display element.

This liquid crystal display element uses a TN (Twisted Nematic) liquid crystal panel 8 as a transmission polarization axis varying means. In this TN liquid crystal panel 8, a TN liquid crystal 15 is sandwiched between two glass substrates 13a and 13b. A blue color polarizing plate 11 is provided on the upper side of the TN liquid crystal panel 8. Below the TN liquid crystal panel 8, the light scatterer 10, the polarization separator 32 and the red EL (El
ectro Luminescence) The backlight 18 is provided in this order.

The color polarization plate 11 is a polarization plate known per se, and as shown by the reference numeral (a) in FIG. 2, when natural light is incident, linear polarization in a predetermined direction (for example, a direction perpendicular to the paper surface) The visible light has a characteristic that it transmits the whole wavelength region, and on the other hand, with respect to linearly polarized light in a direction orthogonal to the visible light region (that is, a direction parallel to the paper surface), only a specific wavelength region (for example, blue) is transmitted without being absorbed.

In the example shown in the upper diagram of FIG. 2, the polarization component in the direction (⊚) perpendicular to the paper surface is transmitted over the entire wavelength range of visible light. In addition, regarding the polarization component in the direction parallel to the paper surface (← →), a specific wavelength range within visible light (for example,
Blue) is transmitted, and other wavelengths are not transmitted.
Therefore, when the linearly polarized light in the direction parallel to the paper surface is incident on the color polarizing plate 11 as indicated by the symbols (b) and (c), only the specific wavelength (for example, blue) can be transmitted through the color polarizing plate 11 and the specific wavelength. Other light is absorbed by the color polarizing plate 11 and cannot pass through it. In addition, as shown by the symbol (d),
When linearly polarized light in the direction perpendicular to the paper surface is incident, light in the entire wavelength region is transmitted through the color polarizing plate 11.

When this color polarizing plate 11 is rotated 90 ° about the central axis L ₀ , the polarization axis directions for transmitting and absorbing linearly polarized light are switched (see the lower diagram of FIG. 2).
That is, for the linearly polarized light in the direction parallel to the paper surface (← →), the entire wavelength region can be transmitted through the color polarizing plate 11, and for the linearly polarized light in the direction vertical to the paper surface (⊚), only the specific wavelength component (blue) can be transmitted.

Regarding which region the above-mentioned specific wavelength of the color polarizing plate 11 is set, the color polarizing plate 11
Can be freely set when manufacturing. In this embodiment, a color polarizing plate that does not absorb light of a blue wavelength, that is, a blue color polarizing plate, or a color polarizing plate that hardly absorbs light of a purple wavelength, that is, a purple color polarizing plate. Will be used.

Returning to FIG. 1, the backlight 1 of this embodiment.
Reference numeral 8 is an EL (electroluminescence) element, and particularly, when the color polarizing plate 11 is a blue color polarizing plate, an EL element that emits red light of a different color or a red light. LED that emits light (light emitting diode, li
ght emitting diode). When a purple color polarizing plate is used, an EL element that emits green light or an LED that emits green light can be used as the backlight (light emitting means 18).

The polarization separator 32 includes a (1/4) λ plate 35 and a cholesteric liquid crystal layer 36. Cholesteric liquid crystal reflects light having the same wavelength as the pitch of the liquid crystal and circularly polarized light in the same rotation direction as the liquid crystal,
It has the property of transmitting other light. So, for example,
If the cholesteric liquid crystal layer 36 is a left-handed cholesteric liquid crystal with a pitch of 5000 angstroms,
It is possible to obtain an element that reflects left circularly polarized light having a wavelength of 5000 Å and transmits right circularly polarized light or differential circularly polarized light having another wavelength.

Furthermore, by using a left-handed cholesteric liquid crystal and changing its pitch within the cholesteric liquid crystal over all wavelengths of visible light, left circularly polarized light is reflected not only in a single color but also in all white light, and right circularly polarized light is reflected. A device that transmits light is obtained. In this embodiment, as the cholesteric liquid crystal layer 36, a left-handed cholesteric liquid crystal is used, and its pitch is changed within the cholesteric liquid crystal over the entire wavelength range of visible light.

In the polarization separator 32 in which the cholesteric liquid crystal layer 36 and the (1/4) λ plate 35 are combined, linearly polarized light in the predetermined first direction is emitted from the (1/4) λ plate 35 side. Is incident, it becomes left-handed circularly polarized light by the (1/4) λ plate 35, is reflected by the cholesteric liquid crystal layer 36, and is again emitted as linearly polarized light in the predetermined first direction by the (1/4) λ plate 35. . When linearly polarized light in the second direction orthogonal to the first direction is incident, the (1/4) λ plate 3
5 becomes right-handed circularly polarized light, and the cholesteric liquid crystal layer 36
Through. Further, with respect to the light incident from the lower side of the cholesteric liquid crystal layer 36, the linearly polarized light in the second direction is emitted above the (1/4) λ plate 35.

As described above, the polarization separator 32 is a combination of the cholesteric liquid crystal layer 36 and the (1/4) λ plate 35.
Of the light incident from the (1/4) λ plate 35 side transmits the linearly polarized light component in the predetermined second direction, reflects the linearly polarized light component in the first direction orthogonal to the predetermined second direction, and (1/4) λ for light incident from the liquid crystal layer 36 side
It is a polarization separation means capable of emitting linearly polarized light in the second direction to the plate 35 side.

As the polarized light separating means having this function, a film in which multilayer films are laminated is used in addition to the polarized light separator 32 in which the cholesteric liquid crystal layer 36 and the (1/4) λ plate 35 are combined. (USP 4,974,
219), which separates into reflected polarized light and transmitted polarized light using the Brewster's angle (SID 92 DIGES
T pages 427 to 429), those using holograms, and internationally published international applications (international application number: W
O95 / 27819 and WO95 / 17692).

Next, the display by the liquid crystal display element will be described with the right half of the liquid crystal display element as a voltage application (ON) portion to the liquid crystal element and the left half as a voltage non-application (OFF) portion.

(Reflective Display Using External Light) First, a reflective multi-color display will be described in which natural light is used and the external light is incident on the liquid crystal display element without using the light emitting means. In the non-voltage applied (OFF) portion on the left side, when external light enters the liquid crystal display element, the external light is linearly polarized P (visible light) in the direction (← →) parallel to the paper surface by the blue color polarizing plate 11. (Only in the short wavelength range of light)
And a linearly polarized light Q (almost all wavelength range of visible light) in the vertical direction (⊚).

The leftmost arrow in FIG. 1 (downward)
Is a linearly polarized light P (only in the short wavelength region of visible light) parallel to the paper surface, is incident on the liquid crystal layer 8, and the polarization direction is twisted by 90 ° by the TN liquid crystal 15 and the light in the direction perpendicular to the paper surface. It becomes linearly polarized light, becomes left circularly polarized light by the (1/4) λ plate 35, is reflected by the cholesteric liquid crystal layer 36, and again becomes (1
/ 4) enters the λ plate 35, becomes linearly polarized light in the direction perpendicular to the paper surface by the (1/4) λ plate 35, enters the liquid crystal layer 8 again, and is twisted by 90 ° in the polarization direction by the TN liquid crystal 15 Becomes a linearly polarized light in a direction parallel to, and is emitted from the blue color polarizing plate 11 as a linearly polarized light in a direction parallel to the paper surface. This is a blue display (light of the second arrow (upward) from the left in FIG. 1).

The light from the third arrow (downward) from the left in FIG. 1 is linearly polarized light Q (almost the entire wavelength range of visible light) in the direction perpendicular to the paper surface and is incident on the liquid crystal layer 8. TN liquid crystal 1
The polarization direction is twisted by 90 ° by 5 to become linearly polarized light in a direction parallel to the paper surface, and the (1/4) λ plate 35 makes right circularly polarized light, which passes through the cholesteric liquid crystal layer 36. After that, the light is added to the backlight 18 and scattered or absorbed depending on the surface state of the backlight 18, but in any case, the light hardly returns to the blue color polarizing plate 11. for that reason,
In the reflective display using external light, no voltage is applied (OF
The F) portion is a blue display due to the polarized light P.

In the voltage application section on the right side, when external light is incident on the liquid crystal display element, the external light is linearly polarized R in a direction parallel to the paper surface (short wavelength region of visible light) by the blue color polarizing plate 11. Only) and linearly polarized light S in the vertical direction (almost the entire wavelength range of visible light).

Of the third light from the right (downward) on the blue color polarizing plate 11 in FIG. 1, linearly polarized light S (almost all wavelength range of visible light) in the direction perpendicular to the paper surface is the liquid crystal layer. Incident on the TN liquid crystal 15 and transmitted through the TN liquid crystal 15 without changing the polarization direction.
/ 4) Left circularly polarized light by the λ plate 35, reflected by the cholesteric liquid crystal layer 36, incident on the (1/4) λ plate 35 again, and linearly polarized light in a direction perpendicular to the paper surface by the (1/4) λ plate 35. Then, the light enters the liquid crystal layer 8 again, and the TN liquid crystal 15
Is transmitted without changing the polarization direction and is emitted from the color polarizing plate 11 as linearly polarized light in a direction perpendicular to the paper surface. This is displayed in white.

On the other hand, linearly polarized light R (only in the short wavelength region of visible light) which is the rightmost light on the blue color polarizing plate 11 in FIG. Incident on 8,
Transmits the TN liquid crystal 15 without changing the polarization direction, (1/4)
The λ plate 35 converts the light into right-handed circularly polarized light and transmits the cholesteric liquid crystal layer 36. After that, scattered by the backlight 18,
The reason why it is reflected and hardly returns to the blue color polarizing plate 11 is the Q when the voltage is off. Therefore, the voltage application (ON) portion at the time of reflection becomes white display by the polarized light S.

As described above, in the reflection type display when the external light is incident on the liquid crystal display element, the non-voltage application section displays blue and the voltage application section displays white. And
When a voltage is applied, the external light that has entered the liquid crystal display element is reflected by the polarization separator 32 without being absorbed, so that a bright display can be obtained.

(Transmissive Display Using Backlight) Next, a transmissive multi-color display by light from the red EL backlight 18 will be described.

First, in the voltage non-applied section on the left side, E
The light T from the L backlight 18 is incident on the cholesteric liquid crystal layer 36 of the polarization separator 32, and only right-handed circularly polarized light is transmitted through the cholesteric liquid crystal layer 36. Direction linearly polarized light, then
The polarization direction is twisted by 90 ° by the TN liquid crystal 15 to become linearly polarized light in a direction perpendicular to the paper surface, and the bluish color polarizing plate 11
Through. This is because the blue color polarizing plate 11 is arranged so as to transmit the linearly polarized light in the direction perpendicular to the paper surface over almost the entire visible light. In other words, the red wavelength range, which is the emission color, is also transmitted and red display is obtained (first
(The fourth light from the left in the figure).

In the voltage applying section on the right side, the red EL
Light U from the backlight 18 is incident on the cholesteric liquid crystal layer 36, only right-handed circularly polarized light is transmitted through the cholesteric liquid crystal layer 36, and becomes linearly polarized light in a direction parallel to the paper surface by the (1/4) λ plate 35. After passing through the light scatterer 10, the TN liquid crystal 15 passes through without changing the polarization direction, and is blocked by the blue color polarizing plate 11. This is because the blue color polarizing plate 11 is arranged so as to transmit linearly polarized light in the direction parallel to the paper surface only in the blue wavelength range. That is, the light in the red wavelength range is absorbed, and black display is obtained (the rightmost light in FIG. 1).

As described above, the red EL backlight 18
In the case of a transmissive display by the light from, the red colored light from the backlight 18 is absorbed by the blue color polarizing plate 11 in the voltage application (ON) portion to be a black display,
In the non-voltage application (OFF) part, the light is transmitted through the blue color polarizing plate 11 and the color display of the EL backlight, that is, red display is performed.

Therefore, this liquid crystal display device can perform bright reflection type multi-color display utilizing reflection of external light in a place where external light is present, and colored EL even in a place where there is no external light. Backlight 18
A reflective liquid crystal display device having a so-called semi-transmissive function, which is capable of performing transmissive multi-color display by light from the. In this embodiment, the two states of the voltage application section and the voltage non-application section have been described, but halftone display is also possible. Further, in the present embodiment, the bluish color polarizing plate 11 is used, but any other color polarizing plate may be used as long as it absorbs a specific wavelength in the visible light region.

(Second Embodiment) FIG. 3 shows another embodiment of the display element according to the present invention. In the embodiment shown in FIG. 1, the polarization separator 32 including the (1/4) λ plate 35 and the cholesteric liquid crystal layer 36 is used, but in the present embodiment, the polarization separator 32 is replaced. , Published international applications (International application number: WO95 / 278
19 and WO95 / 17692), a polarization splitter similar to that disclosed in WO 95/17692, that is, a polarization splitting film 12, is used, which is different from the embodiment of FIG. The other points are the same as those in the embodiment of FIG. 1, and the same members are designated by the same reference numerals.

The polarized light separating film 12 transmits linearly polarized light in a certain direction and reflects other linearly polarized light instead of absorbing it. In particular, linearly polarized light in a direction perpendicular to the transmission polarization axis is totally reflected. Act on. From another point of view, the polarization separation film 12 transmits a linearly polarized light component of a predetermined second direction out of the light incident from the upper side as linearly polarized light of the second direction, and a first direction orthogonal to the second direction. Is a polarization splitting means capable of reflecting the linearly polarized light component of and emitting the linearly polarized light in the second direction to the upper side with respect to the light incident from the lower side.

In FIG. 3, the polarized light separating film 12 is shown.
Reflects the polarization component in the direction perpendicular to the paper (⊚) and transmits the polarization component in the direction parallel to the paper (← →). Here, since the polarization transmission axis (← →) of the polarization separation film 12 and the blue polarization transmission axis (← →) of the blue color polarizing plate are parallel to each other, when external light is used, blue is polarized when the voltage is off. The light is reflected by the separation film 12 and looks blue, and when the voltage is turned on, white is reflected by the polarization separation film 12 and looks white. On the other hand, if the polarization transmission axis of the polarization separation film 12 and the blue polarization transmission axis of the blue color polarizing plate are made orthogonal to each other, the visible colors when voltage is on and when voltage is off are opposite.

This polarization separation film 12 is, for example, the fourth
As shown in the figure, it has a multi-layer structure formed by alternately laminating two types of layers A and B, and between the two layers adjacent to each other in the laminating direction among the plurality of layers A and B, The refractive index in one unidirectional direction is the same between the two layers, and the refractive index in the perpendicular direction is set to be different between the two layers, and the layer thickness of each layer is changed.

In FIG. 4, when considering the directions of three orthogonal axes of XYZ, the two layers A and B are formed in a multilayer state by, for example, extrusion molding, and further, one direction (for example, the X direction).
Along one of the other directions (ie Y direction)
Is not stretched to. That is, the X-axis direction is the stretching direction, and the Y-axis direction is the lateral direction. The B material has a refractive index n _B (eg, n _B = 1.64), which is substantially unchanged by the stretching process. On the other hand, the material A has a characteristic that the refractive index changes due to the stretching treatment. For example, when a sheet made of the material A is stretched in a uniaxial direction, one refractive index n in the stretching direction (that is, the X direction).
_AX (for example, n _AX = 1.88), lateral direction (Y direction)
_Have different refractive indices n _AY (eg, n _AY = 1.64).

The laminated structure of FIG.
If it is stretched in the stretching direction, a large refractive index difference Δn = 1.88-1.64 = 0.24 occurs in the stretching direction. On the other hand, in the Y direction perpendicular to that, the refractive index difference Δn = 1.64 to 1.64 = 0 between the A and B layers, and there is no difference in refractive index. Due to such optical characteristics, when light enters the polarization separation film 12, the polarization component (a) in the transmission axis E direction of the incident light is the polarization separation film 12.
Through. On the other hand, the polarization component (b) of the incident light in the direction of the absorption axis F faces the refractive index difference Δn and is therefore reflected at that portion.

Furthermore, the layer thicknesses t1, t2, t between the A and B layers
The dimensions of 3 …………… are changed little by little, and as a result, as shown in Fig. 5, light (b-1), (b-2)…, having different wavelengths are reflected at the boundary surface of each layer. You can do it. That is, it is possible to efficiently reflect light including all kinds of wavelengths by the two-layer structure of A and B having different layer thicknesses. In the polarization separation film 12 of this embodiment, the layer thicknesses t1, t2, t3, ... Of the respective layers are set so that light of all wavelengths in the visible light range can be reflected.

The surface of the polarization separation film 12 facing the liquid crystal panel 8 may be a smooth surface that specularly reflects light, or a light scattering layer, that is, a light diffusion layer. When the surface is smooth, the reflection image from the polarization separation film 12 is a specular reflection image. Further, when the light diffusion layer is used, the reflection image from the polarization separation film 12 has no pattern and has a single color (usually white) background color. If a color layer is provided on the surface of the polarization separation film 12, an appropriate color can be added.

Next, the display by the liquid crystal display element will be described with the right half of the liquid crystal panel 8 of this liquid crystal display element as the voltage application (ON) portion and the left half as the voltage non-application (OFF) portion. Generally, when it is desired to display a background on the display surface, the liquid crystal panel 8 in that area is turned off, and when information such as numbers is displayed on the display surface, the liquid crystal panel 8 in that area is displayed.
Is turned on.

(Reflective Display Using External Light) Returning to FIG. 3, a reflective multi-color display when external light is incident on the present liquid crystal display element will be described. No voltage applied (O
In the (FF) part, when external light enters the liquid crystal display element, the external light is linearly polarized P in the direction parallel to the paper (← →) and linearly polarized light Q in the direction perpendicular to the paper (⊚) by the blue color polarizing plate 11. Can be divided into In this case, the linearly polarized light P in the direction parallel to the paper surface includes only the short wavelength region of visible light, particularly the wavelength portion corresponding to blue. On the other hand, linearly polarized light Q perpendicular to the paper surface
Is so-called white light that includes almost the entire wavelength range of visible light.

The linearly polarized light P in the direction parallel to the paper surface enters the liquid crystal layer 8 and is twisted by 90 ° in the polarization direction by the TN liquid crystal 15 to become linearly polarized light in the direction perpendicular to the paper surface. This linearly polarized light passes through the light scattering plate 10 and reaches the polarization separation film 12. This linearly polarized light has a polarization separation film 12 depending on the wavelength.
The light is reflected between the inner layers, and the reflected light is incident on the light scatterer 10 and the liquid crystal panel 8 again, is twisted again in the direction parallel to the paper surface by the TN liquid crystal 15, and is transmitted through the blue color polarizing plate 11 to the outside. Is displayed. As a result, the OFF region portion is displayed in the transmission color of the color polarizing plate 11, that is, blue.

On the other hand, the linearly polarized light Q in the direction perpendicular to the paper surface is incident on the liquid crystal layer 8, and the polarization direction is twisted by 90 ° by the TN liquid crystal 15 to become linearly polarized light in the direction parallel to the paper surface. Then, the backlight 18 is reached. This light is scattered or absorbed depending on the surface state of the backlight 18, but in any case, the color polarizing plate 11
Hardly returns to the outside. Therefore, in the reflective display using external light, the voltage non-applied (OFF) portion is polarized P
Is displayed in blue.

Next, in the voltage application (ON) part, when external light is incident on the display element, the external light is linearly polarized R parallel to the paper surface and linearly polarized light perpendicular to the paper surface by the blue color polarizing plate 11. It is divided into S and. In this case, the linearly polarized light R in the direction parallel to the paper surface includes only the short wavelength region of visible light, especially the wavelength portion corresponding to blue. On the other hand, the linearly polarized light S in the direction perpendicular to the paper surface becomes white light including almost the entire wavelength range of visible light.

The linearly polarized light S in the direction perpendicular to the paper surface is the TN liquid crystal 1
5 is transmitted without changing the polarization direction, and the light scatterer 10
After passing through, the light is reflected by the polarization separation film 12 for each wavelength component. Then, the reflected light (all wavelengths) enters the light scatterer 10 and the liquid crystal panel 8 again, is not twisted by the TN liquid crystal 15, passes through the blue color polarizing plate 11 and is emitted to the outside in the direction perpendicular to the paper surface. Since this linearly polarized light contains all wavelength components, the displayed color is white.

On the other hand, the linearly polarized light R parallel to the paper is TN
The liquid crystal 15 is transmitted without changing the polarization direction, further transmitted through the polarization separation film 12, and reaches the backlight 18.
This light is scattered and absorbed on the surface of the backlight 18 and hardly contributes to the display to the outside. Therefore, at the time of the reflective display using the external light, the voltage application (ON) portion displays white due to the polarized light S.

As described above, in the reflection type display when the external light is incident on the liquid crystal display element, no voltage is applied (O
The FF) section displays blue and the voltage application (ON) section displays white. In any display, bright light is obtained because the external light incident on the liquid crystal display element is reflected by the polarization separation film 12 instead of being absorbed.

(Transmissive Display Using Backlight) Next, a transmissive multi-color display using light from the red backlight 18 will be described. In FIG.
In the no voltage application (0FF) part, the light T from the EL backlight 18 passes through the polarization separation film 12 to become linearly polarized light in the direction parallel to the paper surface, and then the TN liquid crystal 15 twists the polarization direction by 90 ° and the paper surface is rotated. It becomes a linearly polarized light in the vertical direction and passes through the blue color polarizing plate 11. This is because the blue color polarizing plate 11 is arranged so as to transmit linearly polarized light in the direction perpendicular to the paper surface over almost the entire visible light. That is, the red wavelength region is also transmitted, and red display is obtained.

On the other hand, in the voltage application (ON) part, the light U from the red EL backlight 18 passes through the polarization separation film 12 to become linearly polarized light in the direction parallel to the paper surface, and then passes through the light scatterer 10. After that, the TN liquid crystal 15 is transmitted without changing the polarization direction, and the blue color polarizing plate 11
It is absorbed by and is blocked from proceeding. This is because the blue color polarizing plate 11 is arranged so that linearly polarized light in the direction parallel to the paper surface transmits only the blue wavelength range. That is, light in the red wavelength range is absorbed, and as a result, it is recognized as black display from the outside.

As described above, regarding the transmissive display using the light from the red backlight 18, the backlight 1
The red colored light from 8 is absorbed by the blue color polarizing plate 11 in the voltage application (ON) part and becomes black display, while in the voltage non-application (OFF) part, the blue color polarization plate 1 is applied.
After passing through 1, the EL backlight 18 is displayed in color, that is, in red. Therefore, the present liquid crystal display device can perform bright reflective multi-color display using reflection of external light in a place where external light is present, and
In a place where there is no external light, transmissive multi-color display can be performed using light from the colored backlight 18. That is, according to the present liquid crystal display element, a reflective liquid crystal display element having a semi-transmissive function can be realized.

In this embodiment, the two states of the voltage applying section and the voltage non-applying section have been described, but halftone display is also possible. Further, in this embodiment, the color polarizing plate 11
Although a bluish one was used for the above, a color polarizing plate of any other color system can be used as long as it has absorption at a specific wavelength in the visible light region.

For example, a violet type color polarizing plate 11 may be used, and a light green EL element or a green LED may be used as the backlight. In this case, when the backlight is turned on and the backlight is turned off, the voltage-off portion changes to green (backlight on) and purple (backlight off). Further, the voltage-on portion changes between black (backlight on) and white (backlight off). Therefore, when the backlight is turned on and off, the visible color changes dramatically,
It is possible to obtain a display element that is easy for the user to see.

Further, in the above description, the liquid crystal panel using the TN liquid crystal as the transmission polarization axis varying means is taken as an example.
A liquid crystal panel or the like using STN liquid crystal or ECB liquid crystal can also be used. In particular, as the STN liquid crystal, it is desirable to use the STN liquid crystal using an optically anisotropic body for color compensation such as F-STN liquid crystal.

Further, as the backlight 18, a cold cathode tube type, LED or the like can be used.

In the above description, it is assumed that the polarization separation film 12 and the backlight 18 are arranged in direct contact with each other. Alternatively, however, the optical element 16 can be arranged between them. As this optical element, for example, a light scatterer, a gray semi-transmissive light absorber, a black light absorber having a plurality of openings,
Various optical elements such as a polarizing plate in which the polarization transmission axis is shifted with respect to the polarization separation film 12 can be considered.

By providing an optical element composed of these various optical elements between the polarization separation film 12 and the backlight 18, the light from the liquid crystal panel 8 side can be absorbed or scattered, and the light from the backlight 18 can be absorbed. Can be transmitted to the liquid crystal panel 8 side, so that a display with high contrast can be obtained.

Polarization separation film 12 and backlight 18
When a black light absorber having a plurality of openings between and is used, it is preferable to limit the ratio of the openings to the light absorber. As a result, it is possible to reduce the amount of light that passes through the light absorber through the opening and is reflected by the backlight 18 or the like and returns again through the opening of the light absorber. As a result, reduction in contrast can be prevented. Further, desirably, by increasing the distance between the light absorber and the backlight, it is possible to reduce the amount of light transmitted through the light absorber reflected by the backlight 18 and returning again. As a result, reduction in contrast can be prevented.

Desirably, by making the surface color of the backlight 18 darker, reflection on the surface of the backlight 18 can be suppressed, and as a result, the light transmitted through the polarization separation film 12 is reflected by the backlight 18. Then, the amount of returning again can be reduced, and therefore, reduction in contrast can be prevented.

Preferably, it further comprises means for condensing the light from the backlight 18 toward the front of the liquid crystal display element. Usually, when viewing a reflection type display using external light, it is common to view it at a position inclined by a certain angle from the normal line to the front of the liquid crystal display element. If the liquid crystal display element is viewed from the direction normal to the front of the liquid crystal display element, the observer himself obstructs the progress of the external light incident on the liquid crystal display element, and the reflection type display due to the external light becomes dark. Is.

On the other hand, when the display by the transmitted light from the backlight 18 is viewed, the light from the backlight 18 is normally viewed from the front of the liquid crystal display element because the light is normally viewed from the direction normal to the front of the liquid crystal display element. By providing a means for condensing light toward the back, the display by the transmitted light from the backlight 18 can be made brighter, and as a result, the transmissive display by the light from the backlight 18 can be displayed on the front surface of the liquid crystal display element. It becomes easier to see in the line direction. A prism sheet, for example, is suitable as a means for condensing the light from the backlight 18 toward the front of the liquid crystal display element.

(Third Embodiment) FIG. 6 shows another embodiment of the liquid crystal display element according to the present invention. This embodiment is a modification of the embodiment shown in FIG. 3, and is different from the embodiment shown in FIG. 3 in that the direction of the polarization transmission axis of the blue color polarizing plate 11 is different from that in FIG. It was rotated 90 degrees.
Therefore, the blue polarization transmission axis of the blue color polarizing plate 11 is perpendicular to the paper surface, and the transmission axis of the polarization separation film 12 is perpendicular to the paper surface. In this case, the operation of the voltage-on unit and the voltage-off unit in FIG. 3 becomes the operation of the voltage-off unit and the voltage-on unit in FIG.

Hereinafter, similar to the case of FIG. 3, the case of the reflective multi-color display utilizing the reflection of external light and the case of the transmissive multi-color display by the light from the backlight will be individually described. To do.

(Reflective Display Using External Light) First, a reflective multi-color display when external light enters a liquid crystal display element will be described. In the voltage non-applied (OFF) portion, when external light is incident on the liquid crystal display element, the external light is divided by the blue color polarizing plate 11 into linearly polarized light P parallel to the paper surface and linearly polarized light Q perpendicular to the paper surface. To be In this embodiment, unlike the case of FIG. 3, the linearly polarized light P in the direction parallel to the paper surface is so-called white light including almost the entire wavelength range of visible light, while the linearly polarized light Q in the direction perpendicular to the paper surface is the short wavelength of visible light. The light includes only the wavelength range corresponding to the region, especially blue.

The linearly polarized light P in the direction parallel to the paper surface is the TN liquid crystal 1
5, the polarization direction is twisted by 90 ° to become linearly polarized light in the direction perpendicular to the paper surface, and is reflected by the polarization separation film 12 as it is as linearly polarized light in the perpendicular direction to the paper surface. Linearly polarized light of
The light is emitted from the blue color polarizing plate 11 as linearly polarized light parallel to the paper surface. This is displayed in white.

On the other hand, the linearly polarized light Q in the direction perpendicular to the paper surface is TN
The polarization direction is twisted by 90 ° by the liquid crystal 15 to become linearly polarized light in the direction parallel to the paper surface, passes through the polarization separation film 12 and reaches the surface of the backlight 18, where it is scattered, absorbed, etc. I won't come back. As a result, the non-voltage application (OFF) portion during the reflective display is displayed in white.

Next, in the voltage application (ON) part, when external light is incident on the liquid crystal display element, the external light is linearly polarized R parallel to the paper surface and linearly perpendicular to the paper surface by the blue color polarizing plate 11. It is divided into polarized light S. In the present embodiment, unlike the case of FIG. 3, the linearly polarized light R in the direction parallel to the paper surface is white light including almost the entire wavelength range of visible light, while the linearly polarized light S in the direction perpendicular to the paper surface is the short wavelength region of visible light, In particular, the light includes only the wavelength part corresponding to blue.

The linearly polarized light S in the direction perpendicular to the paper surface is the TN liquid crystal 1
5 is transmitted without changing the polarization direction, and the polarization separation film 12
And reaches the boundary surface of each layer of the polarization separation film 12 for each wavelength component. This reflected light is transmitted through the TN liquid crystal 15 without changing the polarization direction and is emitted from the color polarizing plate 11 as linearly polarized light in the direction perpendicular to the paper surface. This will be displayed in blue.

On the other hand, the linearly polarized light R parallel to the paper surface is TN
The liquid crystal 15 is transmitted without changing the polarization direction, further transmitted through the polarization separation film 12, and reaches the backlight 18,
There, they are scattered, absorbed, etc. and hardly return to the color polarizing plate 11. As a result of the above, the voltage application (ON) portion at the time of reflective display becomes blue display.

As described above, in the reflective display when external light is incident on the liquid crystal display element, no voltage is applied (O
The FF) section displays white and the voltage application (ON) section displays blue. In any case, the external light that has entered the liquid crystal display element is reflected by the polarization separation film 12 without being absorbed, so that an extremely bright display can be obtained.

(Transmissive Display Using Backlight) Next, a transmissive multi-color display using light from the red EL backlight 18 will be described. No voltage applied (O
In the FF) section, the light T from the EL backlight 18
Enters the polarization separation film 12 and becomes linearly polarized light in the direction parallel to the paper surface, and then the TN liquid crystal 15 twists the polarization direction by 90 ° to become linearly polarized light in the direction perpendicular to the paper surface. Is cut off by. This is because the blue color polarizing plate 11 is arranged so as to transmit linearly polarized light in the direction perpendicular to the paper surface only in the blue wavelength range. In other words, light in the red wavelength range is absorbed, and therefore
A black display is obtained in this part.

On the other hand, in the voltage application (0N) portion, the light U from the red EL backlight 18 enters the polarization separation film 12, becomes linearly polarized light in the direction parallel to the paper surface, and passes through the light scatterer 10. After that, the TN liquid crystal 15 is transmitted without changing the polarization direction, and further is transmitted through the blue color polarizing plate 11. This is because the blue color polarizing plate 11 is arranged so as to transmit linearly polarized light in the direction parallel to the paper surface over almost the entire visible light. By the red light from the backlight 18 that has passed through the color polarizing plate 11, a red display is obtained in that portion.

As described above, the red EL backlight 18
Regarding the transmissive display by the light from the, the red colored light from the backlight 18 is absorbed by the blue color polarizing plate 11 in the non-voltage applied (OFF) portion and becomes black display, while the voltage is applied (ON). Part is blue color polarizing plate 1
After passing through 1, the color display of the EL backlight 18, that is, red display is performed.

Therefore, the present liquid crystal display device can realize a bright reflective multi-color display utilizing the reflection of the external light in the place where the external light is present, while the colored EL backlight can be realized in the place where the external light is not present. A transmissive multi-color display by the light from the light 18 can be realized. That is,
The present liquid crystal display element is a reflection type liquid crystal display element having a so-called transflective function. In the above description, the two states of the voltage application (ON) part and the voltage non-application (OFF) part are illustrated, but halftone display is also possible.

(Modification of Third Embodiment) FIG.
In the figure, a purple color polarizing plate is used as the color polarizing plate 11, and a surface emitting type light green EL is used as the backlight 18.
It is a figure which shows typically the example using an element and a side light type green LED element (LED element is not shown). The optical element 16 may or may not be provided, and
The light scatterer 10 may or may not be provided. Optical element 1
When a light scattering layer, a light diffusing layer, or a light absorbing layer is provided as 6, the external light when the backlight 18 is off and the reflected light on the surface of the backlight 18 and the light emitted from the backlight when the backlight 18 is on are attenuated. be able to. Further, when the light scatterer 10 is provided, specular reflection on the polarization separation film 12 can be softened to give a satin finish.

In this case, when external light is used, segment off (voltage OFF, ground color) is displayed in white, and segment on (voltage ON) is displayed in purple.

When backlight light is used, the segment off (ground color) becomes black and the segment on (that is, 7 segment color) becomes light green (EL) or green (LED).

In this modification, partial reflection of external light on the surface of the backlight 18 facing the polarization separation film 12 (the light emitting surface of the EL element and the light emitting surface of the light guide plate of the LED element) is utilized. Good.

When there is reflection on the surface of the backlight 18, consider the case where external light is used without using the backlight.

First, in the voltage-off section (ground), white light having a polarization axis parallel to the paper surface is transmitted (incident) through the purple color polarizing plate 11 and then reflected by the polarization separation film 12 to be converted into white light parallel to the paper surface. , Is emitted from the purple color polarizing plate 11. Further, violet light having a polarization axis perpendicular to the plane of the paper passes through the violet color polarizing plate 11 and then through the polarization separation film 12 from above,
A part of the light is reflected by the surface of the backlight 18, passes through the polarization separation film 12 from the lower side again, and is emitted from the purple color polarizing plate 11 as violet light vertically polarized on the paper surface. The violet of the vertically polarized light on the paper surface is not completely absorbed or totally reflected by the surface of the backlight 18, but a part thereof is reflected, and further, since it passes through the polarization separation film 12 twice,
The emitted light is weaker than the incident light. Therefore, the color of the voltage-off portion becomes light purple, which is a mixture of white and weak purple. In order to weaken the purple color, it is desirable to provide an optical element 16 that scatters or absorbs light and attenuates the light reflected from the surface of the backlight 18.

In the voltage-on portion (segment), the violet light having the polarization axis perpendicular to the paper surface is reflected by the polarization separation film 12,
It is emitted from the purple color polarizing plate 11 as a violet color which is vertically polarized on the paper surface. Further, the white color of the horizontal polarization axis on the paper surface is transmitted through the polarization separation film 12 and then partially reflected on the surface of the backlight 18, retransmitted through the polarization separation film 12, and is emitted from the purple color polarizing plate 11 as horizontal polarization light on the paper surface. Emit. The white light polarized horizontally in the plane of the paper is not completely absorbed or reflected by the surface of the backlight 18, but is partially reflected and further passes through the polarization separation film 12 twice. become weak. Therefore, the color of the voltage-on portion is a mixture of purple and weak white, but purple is strong. In order to make this white color weaker, it is desirable to provide an optical element 16 that scatters or absorbs light and attenuates the reflected light from the surface of the backlight 18.

In summary, as described above, the user is
You can see purple letters on a light purple background, but purple letters on a light purple background look more beautiful and easier to see than purple letters on a pure white background.

(Fourth Embodiment) FIG. 7 shows still another embodiment of the liquid crystal display element according to the present invention. As the light emitting device up to the third embodiment, an LED placed beside the light guide plate
May be single or plural and are LEDs of the same color, and one light guide plate was used. Further, in the case of an EL element, it is a surface emitting type and a light guide plate is not necessary. On the other hand, in the fourth embodiment, a plurality of different LEDs are used for different effects.

The liquid crystal panel 28 is arranged between the color polarizing plate 21 and the polarization separation film 22 and is denoted by reference numeral 2.
Characters can be displayed in the portions indicated by 8a and 28b. These character display parts 28a and 28b
Corresponding to, the light guide plates 23a and 23b are respectively arranged, and different LEDs are provided for the respective light guide plates.
Light sources 24a and 24b are provided. At the boundary between the light guide plates 23a and 23b, a reflection plate 27 is arranged to prevent the lights from the respective light sources from intermingling with each other. Between the polarization separation film 22 and the light guide plates 23a and 23b, or between the liquid crystal panel 28 and the polarization separation film 22,
A light scattering plate 26 for scattering the backlight light emitted from those light guide plates is provided.

When the light from the LED light sources 24a and 24b is guided to the light guide plates 23a and 23b, respectively, the positions of the LEDs 24a and 24b remain unchanged, and the bottom of the light guide plate is slanted to guide the light to the color polarizing plate 21 side. May be a structure in which the light is reflected in parallel.

(Reflective Display Using External Light) First, a reflective multi-color display when external light enters a liquid crystal display element will be described. In the voltage non-application (OFF) part, when external light is incident, the external light becomes two linearly polarized lights by the color polarizing plate 21 as in the case of FIG. 3 or FIG. The polarized light is turned into linearly polarized light by 90 °, one of the two is reflected by the polarization separation film 22, and the liquid crystal panel 28 again twists the polarized direction by 90 ° and transmits through the color polarizing plate 21. To go out. For example, this is displayed in white.

As described above, when no voltage is applied (OFF), the incident external light is reflected by the polarization separation film 22 instead of being absorbed, so that a very bright reflection type display can be obtained. The light scattering plate 26 can be provided with a light scattering body between the polarization separation film 22 and the liquid crystal panel 28.
The reflected light from the surface is specular to white (satin finis; satin finis
h). In this case, the effect of softening the specular reflection and making it easier to see is produced.

On the other hand, in the voltage application (ON) part, when external light is incident on the liquid crystal display element, the external light is converted into two linearly polarized lights by the color polarizing plate 21, and thereafter, the liquid crystal panel 28 is polarized respectively. Transparent without changing,
One linearly polarized light is transmitted through the polarization separation film 22 without changing the polarization direction, and then scattered and depolarized by the light scattering plate 26, and almost no light returns to the liquid crystal panel 28 side. Then, the other linearly polarized light is reflected by the polarization separation film 22, then passes through the color polarizing plate 21, and is emitted to the outside. For example, this is color display by the color polarizing plate 21.

(Transmissive Display Using Backlight) Next, a backlight, that is, a transmissive display using light from the light guide plates 23a and 23b will be described. In the no voltage application (0FF) part, the light guide plates 23a and 23b
Light enters the polarization separation film 22 and becomes linearly polarized light, and then the liquid crystal panel 28 changes the polarization direction to 90 degrees.
It is twisted and absorbed by the color polarizing plate 21 to display black.

On the other hand, in the voltage application (ON) part, the light from the light guide plates 23a and 23b is polarized by the polarization separation film 22.
To become linearly polarized light, which becomes scattered light by the light scatterer 26, and then transmits through the liquid crystal panel 28 without changing the polarization direction, and also through the color polarizing plate 21 to provide a color display corresponding to the colored layer. Since the light guide plates 23a and 23b are provided with different LED light sources 24a and 24b corresponding to the character display portions 28a and 28b, the respective character display portions can be displayed in different colors.

Therefore, in this liquid crystal display element, bright reflection type display utilizing reflection of external light can be performed in a place where external light is present, and light sources 24a and 24b can be used even in a place where no external light is present. The liquid crystal display device can perform a transmissive display by the above light and has a so-called semi-transmissive function. In addition, multicolor display is possible by using light sources that emit different colors.

(Fifth Embodiment) FIG. 8 shows still another embodiment of the liquid crystal display element according to the present invention. This embodiment is different from the previous embodiment shown in FIG. 7 in that instead of the LED light source having different light guide plates 23a and 23b shown in FIG. 7, a plurality of LED light sources 34a and 34b are of direct type. It was used as a light source. Also in this embodiment, both light sources 3
A reflection plate 27 is provided between 4a and 34b to prevent the lights from the respective light sources from intermingling with each other.
It should be noted that each member shown in FIG. 8 and denoted by the same reference numeral as in FIG. 7 indicates the same member, and therefore detailed description thereof will be omitted.

One of the LED light sources 34a is L which emits red light.
The LED light source 34b is a set of ED elements, and the other LED light source 34b is a set of LED elements that emit blue. The character display portions 28a and 28b corresponding to the respective light source portions can be displayed in different colors during transmissive display. Specifically, the character display unit 28a can be displayed in red and the character display unit 28b can be displayed in blue. It should be noted that during reflective display, the seventh
Display is performed according to the same principle as in the case of the figure. Also, blue L
A blue EL element may be used instead of the ED element 34b.

(Sixth Embodiment) FIG. 9 shows still another embodiment of the liquid crystal display element according to the present invention. This embodiment is different from the previous embodiment shown in FIG. 7 in that instead of the LED light source having different light guide plates 23a and 23b shown in FIG. 7, an EL element 44a that emits red and a color that emits green are produced. To E
That is, the L element 44b was used as a direct type light source. The EL elements 44a and 44b correspond in position to the character display portions 28a and 28b, respectively.
It should be noted that each member shown in FIG. 9 and denoted by the same reference numeral as in FIG. 7 indicates the same member, and therefore detailed description thereof will be omitted.

The character display portions 28a and 28b corresponding to the light source portions 44a and 44b can be displayed in different colors during transparent display. Specifically, the character display unit 28a can be displayed in red and the character display unit 28b can be displayed in green. During the reflective display, the display is performed according to the same principle as that shown in FIG.

(Seventh Embodiment) FIG. 10 shows still another embodiment of the liquid crystal display device according to the present invention. In the embodiment of FIG. 7, the polarization separation film 22 and the light guide plates 23a, 2
Although the light scattering plate 26 is disposed between the polarization separation film 22 and the light guide plate 23, the light scattering plate 26 is disposed between the polarization separation film 22 and the light guide plate 23. A film 47 is provided. The members shown in FIG. 10 that are denoted by the same reference numerals as those in FIG. 7 indicate the same members, and therefore detailed description thereof will be omitted.

Character display portions 28a and 28b corresponding to the respective colored portions 47a and 47b of the colored film 47.
Can be displayed in different colors during transparent display. In particular,
The character display portion 28a can be displayed in red and the character display portion 28b can be displayed in blue. During the reflective display, the display is performed according to the same principle as that shown in FIG.

(Eighth Embodiment) FIG. 11 shows still another embodiment of the liquid crystal display device according to the present invention. Tenth
In the illustrated embodiment, the coloring film 47 is arranged between the polarization separation film 22 and the light guide plate 23. In this embodiment, in addition to the structure, the polarization separation film 22 and the coloring film 4 are provided.
A light absorbing plate 46 in a semi-transmissive gray state is disposed between the light absorbing plate 46 and the light receiving plate 7. The members shown in FIG. 11 and denoted by the same reference numerals as those in FIG. 7 indicate the same members, and therefore detailed description thereof will be omitted.

In this embodiment, the light absorption plate 46 in the semi-transmissive gray state allows the light passing through the polarization separation film 22 during the reflective display to be guided by the light guide plate 23 and the colored film 47.
It is possible to suppress the reflection at. Instead of the light absorbing plate 46, it is possible to use a light absorbing body having an opening, a polarizing plate whose transmission axis is shifted with respect to the polarization separation film 22, or the like.

(Ninth Embodiment) FIG. 12 shows still another embodiment of the liquid crystal display device according to the present invention. In this embodiment, the color polarizing plate 31 has two parts 31 of different colors.
It is divided into a and 31b. Other configurations are 11th
Since it is the same as the case of the figure, detailed description thereof will be omitted. According to the present embodiment, by dividing the color polarizing plate 31 into two, the character display portions 28a and 28a are separated.
8b can be colored with different colors corresponding to their respective parts.

(Tenth Embodiment) FIG. 13 shows still another embodiment of the liquid crystal display device according to the present invention. In this embodiment, the prism sheet 43 is arranged between the backlight 54 and the colored film 47. 7th with other members
The same reference numerals as those used in the drawings indicate the same members, and detailed description thereof will be omitted. In the present embodiment, by using the prism sheet 43, the light from the backlight 54 can be condensed toward the front surface of the liquid crystal display element, and therefore the brightness at the time of transmissive display can be further increased. You can As the prism sheet 43, for example, DEF-90 (trade name) manufactured by 3M can be used.

(Eleventh Embodiment) FIG. 14 shows a sectional structure of an electronic timepiece according to an embodiment of the present invention. This wristwatch includes, for example, a plastic casing 1, a movement 2 stored inside the casing 1, a glass plate 3 fixed to the casing 1 and located on the movement 2, and a movement 2 fixed thereto. And a back cover 4 to be used. Reference numeral 6 indicates an arm band.

As shown in FIG. 16, the movement 2 has a panel frame 7, a display element 5 supported by the panel frame 7, and a battery 9 arranged on the back side of the display element 5. The display element 5 has, for example, the structure shown in FIG. 3, and therefore, the display element 5 includes a liquid crystal panel 8 as a transmission polarization axis varying means supported by the panel frame 7, and the liquid crystal panel 8 of the liquid crystal panel 8. Outer surface (upper surface in the figure)
Polarizing plate 1 as first polarized light separating means adhered to
1 and a polarization separation film 12 as a second polarization separation means arranged on the opposite side of the polarizing plate 11 with the liquid crystal panel 8 interposed therebetween.
And a backlight 18 disposed on the bottom surface side of the polarization separation film 12. The light scatterer 10 is disposed between the polarization separation film 12 and the liquid crystal panel 8.

The liquid crystal panel 8 has a pair of transparent glass substrates 13a and 13b facing each other, and a liquid crystal, for example, a TN liquid crystal 15 is sealed in a gap formed between these glass substrates, a so-called cell gap. . Glass substrate 1
Each of 3a and 13b has a plurality of transparent electrodes 1 for displaying information such as numbers and letters as shown in FIG.
4 are formed so as to face each other between both substrates. In this embodiment, a transparent electrode divided into 7 segments is used as a transparent electrode for displaying a one-digit number.

A predetermined voltage can be applied between the pair of segment transparent electrodes 14 facing each other. Depending on whether the voltage is applied (ON) or not applied (OFF), the liquid crystal 15 is discharged. The orientation can be set to one of two states. The liquid crystal of the present embodiment does not change the polarization axis of the linearly polarized light passing through the liquid crystal when it is in the ON state, while the polarization axis of the linearly polarized light that passes through the liquid crystal when it is in the OFF state is 90 °. It is set to twist only by °.

The way in which information such as numbers displayed on the display element 5 is displayed is the same as that already described with reference to FIG. 3 and therefore will not be described here. In conclusion, clock display such as numbers and letters is shown. Can be displayed in a semi-transmissive and reflective multi-color display, and can be displayed in a very bright display state.

The relationship between the transmission axis of the color polarization plate and the transmission axis of the polarization separation film and the relationship between the colors visible on the outside of the color polarization plate is summarized in the table on the next page.

[0160]

[Table 1]

(Note) When the light emitted from the backlight includes a specific wavelength that is transmitted by the color polarizing plate, the color has the specific wavelength. However, in the present invention, the light from the backlight is transmitted through the color polarizing plate. Since it is configured so that it does not pass through, it becomes black.

[0162]

As described above, according to the present invention, a display element capable of multicolor display and an electronic timepiece using the same can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an embodiment of a display element according to the present invention.

FIG. 2 is a diagram schematically showing the function of a color polarizing plate used in the display element of FIG.

FIG. 3 is a diagram schematically showing another embodiment of the display element according to the present invention.

FIG. 4 is a diagram schematically showing the function of a polarization separation film used in the display device of FIG.

5 is a cross-sectional view of the polarization separation film of FIG.

FIG. 6 is a diagram schematically showing still another embodiment of the display element according to the present invention.

FIG. 7 is a perspective view schematically showing still another embodiment of the display element according to the present invention.

FIG. 8 is a perspective view schematically showing still another embodiment of the display element according to the present invention.

FIG. 9 is a perspective view schematically showing still another embodiment of the display element according to the present invention.

FIG. 10 is a perspective view schematically showing still another embodiment of the display element according to the present invention.

FIG. 11 is a perspective view schematically showing still another embodiment of the display element according to the present invention.

FIG. 12 is a perspective view schematically showing still another embodiment of the display element according to the present invention.

FIG. 13 is a perspective view schematically showing still another embodiment of the display element according to the present invention.

FIG. 14 is a sectional view showing an embodiment of an electronic timepiece according to the invention.

FIG. 15 is a plan view showing a main part of the electronic timepiece shown in FIG.

16 is a cross-sectional view of the structure of FIG.

FIG. 17 shows an example in which a purple color polarizing plate is used as the color polarizing plate in FIG.

[Explanation of symbols]

8 LCD panel 11 color polarizer 15 TN liquid crystal 10 Light scatterers 12 Polarization separation film 16 Optical element 18 backlight 21 Color Polarizer 22 Polarization separation film 28 LCD panel 26 Light Scatterer 34 LED 44 EL 23 Light guide plate 46 Light absorbing plate 47 Coloring film

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI G04G 9/06 G04G 9/06 (56) References JP-A 1-210931 (JP, A) JP-A 7-333598 (JP , A) JP-A-9-138406 (JP, A) JP-A-10-115828 (JP, A) International Publication 97/001788 (WO, A1) International Publication 99/006883 (WO, A1) (58) Field (Int.Cl. ⁷ , DB name) G02F 1/1335 G02F 1/13 505 G02F 1/13357

Claims (3)

(57) [Claims] 1. A transmission polarization axis varying means capable of changing the transmission polarization axis, and a first polarization separating means and a second polarization separating means arranged on both sides of the transmission polarization axis varying means, with the transmission polarization axis varying means interposed therebetween. A light source arranged on the opposite side of the transmission polarization axis varying means with the second polarization separating means interposed therebetween, and the first polarization separating means is configured to convert all wavelength components in the visible light range with respect to linear polarization components in the first direction. The second polarized light separating means has a function of transmitting the linearly polarized light component in the second direction orthogonal to the first direction and transmitting a specific wavelength component in the visible light region but not other wavelength components. Has a function of transmitting the linearly polarized light component in the third direction and reflecting the linearly polarized light component in the direction orthogonal to the third direction, and the light source emits colored light, and the transmission polarization axis varying means is provided. The light source An optical element between the
And the optical element absorbs light from the second polarization separation means side.
The light emitted from the light source is separated into the second polarized light while being collected.
Transmits toward the separating means side and reduces external reflection light from the light source.
To absorb light, it absorbs light in almost the entire wavelength range of the visible light range.
The light absorber that collects light has an opening that allows light to pass through.
Electronic watch, characterized in that. 2. The light source according to claim 1, wherein the light source is at least one LED element or at least one EL element.
An electronic timepiece including a (electroluminescence) element. 3. The electronic timepiece according to claim 1, wherein the transmission polarization axis varying means is liquid crystal.