JP2001201731A - Liquid crystal display illuminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately illuminate a selected segment even when temperature is changed. SOLUTION: This liquid crystal display illuminator is provided with a display panel 10 having plural display segments sealed with a liquid crystal layer for switching a diffusion state to/from a transmission state, a selector 50 for selecting one display segment among plural display segments of the display panel 10, a drive circuit 7 for making the display segment selected by the selector 50 into the diffusion state and driving non-selected areas into the transmission state, a light source 30 for illuminating the display panel 10 and an optical guide device 40, a photometric element 9 for detecting the temperature of the liquid crystal layer or its vicinity, and a CPU 8 (S11) for controlling a delay time until the light source 30 starts the illumination after the selector 50 is operated and a light emitting time until the light source 30 ends the light emitting after the light source 30 starts the light emitting based on the detection temperature detected by the photometric element 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display illuminating device for illuminating a transmission type liquid crystal panel capable of displaying necessary information superimposed on an optical image, and more particularly to a finder device for a camera. The present invention relates to a liquid crystal display lighting device which can be suitably used for superimposed display and the like.

[0002]

2. Description of the Related Art A liquid crystal panel is a transmission type display device capable of superimposing and displaying necessary information on an optical image. For example, a liquid crystal panel using a polymer dispersed liquid crystal is used for a camera. Used for finder devices. This liquid crystal panel is a panel including a plurality of display segments each having a liquid crystal layer in which a polymer dispersed liquid crystal is sealed between two transparent substrates with transparent electrodes. By controlling the electric field applied to the liquid crystal layer, the polymer-dispersed liquid crystal displays two modes, that is, a transmission state in which light is transmitted and a diffusion state in which light is diffused.

When this liquid crystal panel is driven, display segments to which an electric field is applied transmit light, and display segments to which no electric field is applied diffuse (scatter) light. Thus, when an optical image such as an outside scene is bright, the display segment looks dark, while when the image is dark, the display segment can be made bright by illuminating the liquid crystal layer.

[0004]

However, the response of this polymer-dispersed liquid crystal becomes slower as the temperature becomes lower.
Simply performing the illumination causes a problem that the lighting of the display segment and the timing of the illumination do not match.

For example, at room temperature of 25 ° C., the time required for a polymer-dispersed liquid crystal to change from a diffusion state to a transmission state is about 10 msec, and the time required to change from a transmission state to a diffusion state is about 10 msec. 60 msec, almost instantaneous. However, at a low temperature of −10 ° C., the time required to change from the diffusion state to the transmission state is about 300 m.
Second, the time required to change from the transmission state to the diffusion state is about 1400 msec, and the response is extremely slow.

Therefore, when one of a plurality of segments is selected by a selector, the response of the liquid crystal is slow at a low temperature. Therefore, when the timing of illumination is linked to the operation of the selector, the selected segment changes to a diffused state. Before that, the lighting will end. Furthermore, there is a problem that the previously selected segment is illuminated, and the selected segment is not correctly illuminated. This problem has not been solved at present.

An object of the present invention is to solve the above-mentioned problems and to provide a liquid crystal display illuminating device capable of appropriately illuminating a selected segment even when there is a temperature change. .

[0008]

In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a plurality of display segments in which a liquid crystal layer for switching between a diffusion state for diffusing light and a transmission state for transmitting light is sealed. A display panel having at least one of a plurality of display segments of the display panel.
A selection unit (50) for selecting one display segment; a driving circuit (7) for setting the display segment selected by the selection unit to the diffusion state and driving an unselected area to the transmission state; An illumination unit (30, 40) for illuminating the display panel; a temperature detection unit (9) for detecting a temperature of or near the liquid crystal layer; and the selection based on the detected temperature detected by the temperature detection unit. An illumination control unit (8, S1) that controls a delay time from when the illumination unit starts operating after the operation of the illumination unit and / or a light emission time from when the illumination unit starts emitting light to when the illumination unit ends.
1) A liquid crystal display lighting device including:

According to a second aspect of the present invention, in the liquid crystal display illuminating apparatus according to the first aspect, the illumination control unit determines the delay time by causing the display segment of the display panel at the detected temperature to transmit the display segment from the diffusion state. The liquid crystal display lighting device is characterized in that the setting is made longer than the time until the state is switched.

According to a third aspect of the present invention, in the liquid crystal display certification device according to the first aspect, the illumination control unit is configured to change the delay time from the transmission state of the display segment of the display panel at the detected temperature. The liquid crystal display lighting device is characterized in that it is set to be shorter than the time required to switch to the diffusion state.

According to a fourth aspect of the present invention, in the liquid crystal display lighting device according to the first aspect, the illumination control section sets the light emission time to a time when the display segment of the display panel switches from the transmission state to the diffusion state. The liquid crystal display lighting device is characterized in that the setting is performed during or for a longer time.

According to a fifth aspect of the present invention, in the liquid crystal display lighting device according to the first aspect, a photometric unit (9) for measuring the brightness of the display panel or the vicinity thereof, and a photometric value obtained by the photometric unit is a predetermined luminance. In the above case, there is provided a liquid crystal display lighting device comprising: a light emission prohibition unit (S8) for prohibiting light emission of the lighting unit.

According to a sixth aspect of the present invention, in the liquid crystal display lighting device according to the first aspect, the illuminating section includes a light source (30) for generating light and a light guide for guiding the light from the light source to the display panel. And a liquid crystal display lighting device comprising:

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described in more detail.
FIG. 1 is a diagram conceptually illustrating the structure of a single-lens reflex camera incorporating a liquid crystal display lighting device according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a control system of the liquid crystal display lighting device according to the present embodiment. This camera 1 is shown in FIG.
As shown in FIG. 1, a photographing lens 2 for forming an image of a subject on a film, a light-flooding reflecting mirror 3 for switching an optical path from the photographing lens 2, and a screen 4 arranged on a surface conjugate to the film. A display panel 10 of a polymer dispersed liquid crystal disposed in close proximity to the screen 4, a pentaprism 5 for bending the screen 4 and light transmitted through the display panel 10 for observation, and projected on the screen 4. An eyepiece 6 for observing an image is provided. Here, the display panel 10 is held by the holder 20 and fixed to the camera.

The camera 1 has a display device,
In addition to the display panel 10, a light source 30 composed of an LED or the like
A light guide device 40 for guiding light from the light source 30 to the end face 10a of the display panel 10, a driving circuit 7 for driving the display panel 10, a CPU 8, a photometric element 9, and a display panel 1.
And a selector 50 for selecting a zero segment.

The light source 30 is, as shown in FIG.
1 and a drive circuit 32 for driving the LED 31. The light of the LED 31 of the light source 30 is guided by the light guide device 40 to the end face 10 a of the display panel 10.

The CPU 8 includes an AE device (not shown) and an A
This is a central processing unit that controls the operation of the camera as a whole based on signals from the F device and the like. In this embodiment, the driving circuit 7 is further provided based on a signal from the selector 50.
, The display state of the display panel 10 is controlled.

The photometric element 9 is constituted by an IC, is a photoelectric conversion element for detecting the luminance of the subject, and is an element for outputting a voltage proportional to the absolute temperature. That is, the photometric element 9 measures the light transmitted through the photographing lens 2, jumped up by the reflection mirror 3, and diffused by the screen 4 disposed on a plane conjugate with the film, and transmits the luminance signal to the CPU 8. Output. In this embodiment, the photometric element 9 also measures the brightness of the display panel 10 or the vicinity thereof.

The photometric element 9 has an absolute temperature proportional temperature V
ref is detected and output to the CPU 8. When the absolute temperature proportional voltage is Vref, this voltage at 25 ° C. is stored in the camera as a reference voltage V0, and the predetermined temperature θ (° C.) is obtained by detecting the absolute temperature proportional voltage Vref. It can be calculated by the following equation (1). θ = (Vref / V0) × 298-273 (1) That is, the temperature θ (° C.) can be calculated by detecting the voltage Vref.

FIGS. 3 and 4 are views showing the display panel 10 of the liquid crystal display lighting device according to the present embodiment. As described above, the display panel 10 is made of a polymer-dispersed liquid crystal. For example, as shown in FIG.
With five segments from 1 to 105, the selector 50
, One of the segments 101 to 105 is selected. FIG.
Indicates a selected state.

The display panel 10 is driven by a drive circuit 7. When receiving a signal for updating the drive from the CPU 8, the drive circuit 7 performs an update process for switching the designated segment from the transparent state to the diffused state while setting the diffused segment to the transparent state. The drive circuit 7 is configured to turn on the central segment 101 when a battery is first inserted into the camera.

FIG. 5 is a diagram showing the selector 50 of the liquid crystal display lighting device according to the present embodiment. The selector 50 includes, for example, four switches 51 to 54, and can use an AF area selector 501 that detects that the switch is pressed in four directions, up, down, left, and right.

Next, the operation of the camera 1 of FIG. 1 will be described.
The image light formed on the screen 4 by the taking lens 2 is
Since the display panel 10 is arranged close to the screen 4, the background (background area) of the display panel 10
Pass as it is. When any of the portions of the display panel 10 other than the background (that is, the portions of the display segments 101 to 105) is in a diffused state,
Light incident on this portion is diffused and diffused in all directions, so that light traveling toward the eyes is only a small part.
Therefore, the portion displayed with the reduced light amount in this portion is darker than the background. That is, the display panel 10 optically superimposes the background and the display pattern.

When sufficient light does not reach the screen 4, the light source 30 is turned on and an appropriate amount of illumination light is incident from the end face 10a of the display panel 10 to provide a bright display in a dark background. The pattern can be superimposed and displayed. In this case, since light is diffused in a segment to be displayed (any of segments 101 to 105), a part of the illumination light is also diffused in the direction of the observer's eyes. Segment appears bright. However, when the luminance of the subject is sufficiently bright, even if the light source 30 is turned on and the illumination light is incident from the end face 10a of the display panel 10, the illumination light is too dark compared with the luminance of the subject, so that the light is bright. Instead of a display pattern, a dark display pattern is superimposed on a light background.

Next, the operation of the camera corresponding to the response delay of the polymer dispersed liquid crystal using such a superimposable liquid crystal display lighting device will be described. Figure 5
FIG. 7 shows the CPU 8 of the liquid crystal display lighting device according to the present embodiment.
6 is a flowchart showing the operation of the embodiment. When the battery of the camera is loaded, the operation starts, and S1 is executed.

In S1, 0 is entered in the parameter A. The parameter A indicates the selected segment, where 0 is center, 1 is right, 2 is left, 3 is up, and 4 is down. As described above, when the camera is first loaded with a battery, the drive circuit 7 sets the parameter A to 0 in order to bring the central segment 101 into a diffused state.

In S2, it is determined whether the AF area selector 501 has been pressed in any of up, down, left and right directions. Details will be described with reference to FIG. In FIG. 7, in S201, 1 is set to the flag F. The flag F is set to 0 when the AF area selector 501 is not pressed in any of the up, down, left, and right directions, and indicates whether the AF area selector 501 has been operated.

In steps S202 to S208, when the switch 51 is pressed, it is determined which segment is to be in the diffusion state next depending on which segment was in the diffusion state before that. At present, if any of the center, upper and lower segments is in the diffused state (A is 0 or 3 or 4), 1 is put into A so that the right segment is in the diffused state. Currently, the left segment is in a diffuse state (A = 2)
, A is set to 0 so that the central segment is in a diffuse state. If the right segment is currently in the diffused state (A = 1), the value of the parameter A is not changed because the diffused state of the right segment may be held.

In steps S209 to S215, as described above,
Change to the left side. In S216 to S222,
In the same manner as described above, an upward change process is performed. S223-
In S229, a downward change process is performed in the same manner as described above.

In S230, when none of the switches 51 to 54 is pressed and the AF area selector 501 is not operated, 0 is set to the flag F. Upon completion of the above, the procedure returns to S3 in FIG.

In FIG. 6, a flag F is determined in S3. If F = 0, the AF area selector 501
Is not operated, the process returns to S2. If F = 1,
Since the AF area selector 501 has been operated, the process proceeds to S4.

At S4, an update signal is output to the drive circuit 7 so that the segment selected at S2 is displayed on the display panel 10 in a diffused state. In response to this, the drive circuit 7 outputs a signal for setting the segment in the current diffusion state on the display panel 10 to the transmission state and setting the selected segment to the diffusion state.

In S5, the luminance of the screen 4 is calculated by receiving the output of the photometric element 9. In S6, screen 4
It is determined whether or not the upper luminance is equal to or less than a predetermined value. If the value is larger than the predetermined value, even if the LED 31 of the light source 30 is turned on, it is too dark compared to the brightness of the subject, and the display pattern does not become bright. Therefore, the process of turning on the LED 31 is not performed. Return. If the value is equal to or less than the predetermined value, the LED 31 of the light source 30 is turned on by the drive circuit 32, illumination light is made to enter from the end face 10a of the display panel 10, and a superimposed bright display pattern is performed on a dark background. Is performed. When an apex value is used as an example of the predetermined value of the luminance (BV-AVo) on the screen 4, a value of about 2.5 is preferable, and a value between about 1 and 4 is good.

At S7, a time parameter t used for timing is set to 0. In S8, time measurement is started, and this time is set to t. In S9, the absolute temperature proportional voltage Vref is detected from the photometric element 9. In S10, using the absolute temperature proportional voltage Vref detected in S9, the temperature θ (° C.) is calculated from the above equation (1).

In S11, the delay time Td and the light emission time Ti of the LED 31 are determined until the light emission of the LED 31 is started, based on the temperature θ (° C.) calculated in S10. Details will be described with reference to FIG.

In FIG. 8, in S301, when the temperature θ is 5
It is determined whether the temperature is higher than ° C. When θ> 5 ° C., S
The process proceeds to 303, and when θ ≦ 5 ° C., proceeds to S302. S30
In 2, it is determined whether the temperature θ is higher than −5 ° C. θ
If> -5 ° C, proceed to S304; if θ ≦ -5 ° C, proceed to S305.

In S303, the delay time Td is set to 50 ms, and the light emission time Ti is set to 300 ms. In S304, the delay time Td is set to 150 ms, and the light emission time Ti is set to 350 ms. In S305, the delay time Td is set to 6
00 ms and 500 ms for the emission time Ti.

That is, here, the delay time Td and the light emission time Ti are determined according to the temperature θ as shown in the following table. θ ≦ −5 ° C. −5 ° C. <θ ≦ 5 ° C. 5 ° C. <θ Td = 600 ms Td = 150 ms Td = 50 ms Ti = 500 ms Ti = 350 ms Ti = 300 ms

As described above, the delay time Td and the light emission time Ti
Is determined until the segment that has been in the diffused state before the operation of the AF area selector 501 of the display panel 10 becomes a transparent state, and then the LED 31 of the light source 30 starts to emit light. Lighting continues to emit light while the segment selected by 501 changes from the transmissive state to the diffused state, and displays a bright display pattern in a dark background that does not feel uncomfortable with the segment switching delay of the display panel 10. This is in order to achieve superimposition. After the above processing is completed, the process returns to S12 of FIG.

In FIG. 6, in S12, it is determined whether or not the counted time t is longer than the delay time Td determined in S11. If it is less, the process stays at S12, and if it is more, the process goes to S13. In S13, the driving circuit 3 of the light source 30
2, the lighting of the LED 31 is started. Thereby, the lighting segment of the display panel 10 (segment 10 in FIG. 3)
1 to 105) appear bright.

In S14, it is determined whether or not the time t is equal to or greater than the sum of the delay time Td and the light emission time Ti determined in S11. If it is less, the process stays at S14, and if it is more, the process goes to S15.

In S15, the driving circuit 32 of the light source 30 terminates the lighting of the LED 31. From S12 to S1
5, after operating the AF area selector 501,
The LED 31 of the light source 30 emits light only during the light emission time Ti after the delay time Td to illuminate the diffused segment of the display panel 10 brightly. In S16, the time counting started in S8 ends, and the process returns to S2.

As described in detail above, in the present embodiment, the temperature is detected by the absolute temperature proportional voltage Vref of the photometric element 9, and the delay time Td and the light emission time Ti, which are the light emission start timing of the light source 30, are determined. I did it. At this time, before the operation of the AF area selector 501 of the display panel 10 of the polymer dispersed liquid crystal, the segment that was in the diffusion state was changed to the transmission state, and then the light emission of the LED 31 of the light source 30 was started. Even if the response of the polymer-dispersed liquid crystal becomes low and the response becomes slow, the two segments are not illuminated at the same time. For this reason, superimposed display using lighting that does not cause discomfort is achieved.

That is, the polymer-dispersed liquid crystal is used in consideration of the temperature response of the polymer-dispersed liquid crystal, which changes from the diffusion state to the transmission state faster than the change from the transmission state to the diffusion state. In the illumination of the display device, the start of the illumination is delayed in response to the response delay of the liquid crystal due to the temperature, in particular, the change from the diffusion state to the transmission state, so that two segments are simultaneously illuminated. There is no.

Also, since the segment selected by the AF selector 501 emits light during the transition from the transmission state to the diffusion state, even if the response of the liquid crystal becomes considerably slow at a low temperature, the light source is slightly delayed. Emits light so that the user does not easily notice the delay of the light emission timing. For this reason, the superimposition of the lighting which does not have a more unnatural feeling is achieved.

That is, in the low temperature region, the illumination is started after the change of the display device of the polymer dispersed liquid crystal from the diffusion state to the transmission state is completed and during the change from the transmission state to the diffusion state. In particular, the present invention provides a display device with less discomfort in which the response of the liquid crystal becomes less noticeable because the light source illuminates faster than the response of the polymer dispersed liquid crystal at a low temperature. Was completed.

[0047]

As described in detail above, the delay time until the start of light emission of the illumination unit and the light emission time are changed depending on the temperature of the liquid crystal layer, so that the selected display segment can be correctly displayed. Can be illuminated. At this time,
Since the start of the illumination is delayed in response to the change from the diffusion state to the transmission state, the two segments are not illuminated at the same time. In addition, since the illumination is started during the transition from the transmission state to the diffusion state, the response of the liquid crystal layer is less noticeable, and display illumination with less discomfort can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram conceptually illustrating the structure of a single-lens reflex camera incorporating a liquid crystal display lighting device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a control system of the liquid crystal display lighting device according to the present embodiment.

FIG. 3 is a diagram showing the display panel 10 of the liquid crystal display lighting device according to the present embodiment.

FIG. 4 is a diagram showing the display panel 10 of the liquid crystal display lighting device according to the present embodiment.

FIG. 5 is a diagram showing a selector 50 of the liquid crystal display lighting device according to the present embodiment.

FIG. 6 illustrates a CPU 8 of the liquid crystal display lighting device according to the present embodiment.
6 is a flowchart showing the operation (main routine) of FIG.

FIG. 7 is a CPU 8 of the liquid crystal display lighting device according to the present embodiment.
Is a flowchart showing the operation (subroutine of selection area determination).

FIG. 8 shows a CPU 8 of the liquid crystal display lighting device according to the present embodiment.
3 is a flowchart showing the operation (subroutine for determining the delay time and the light emission time).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera 2 Shooting lens 3 Reflecting mirror 4 Screen 5 Pentaprism 6 Eyepiece 7 Drive circuit 8 CPU 9 Photometric element 10 Display panel 20 Holder 30 Light source 40 Light guide device 50 Selector

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 17/20 G09G 3/04 D 5C080 G09G 3/04 3/18 3/18 G02F 1/1335 530 F term (Ref.) DD20 EE28 FF03 JJ01 JJ02 JJ07 KK52

Claims (6)

[Claims] 1. A display panel having a plurality of display segments enclosing a liquid crystal layer for switching between a diffusion state for diffusing light and a transmission state for transmitting light, and at least one of the plurality of display segments of the display panel. A selection unit that selects a display segment; a driving circuit that sets the display segment selected by the selection unit to the diffusion state and drives an unselected region to the transmission state; and illumination that illuminates the display panel. Unit, a temperature detection unit that detects the temperature of the liquid crystal layer or its vicinity, based on the detected temperature detected by the temperature detection unit,
A delay time until the lighting unit starts lighting after the selection unit is operated, and / or a lighting control unit that controls a light emitting time from when the lighting unit starts emitting light to when the lighting unit ends. Liquid crystal display lighting device including. 2. The liquid crystal display lighting device according to claim 1, wherein the lighting control unit sets the delay time until the display segment of the display panel at the detected temperature switches from the diffusion state to the transmission state. A liquid crystal display lighting device characterized by being set to be longer than the time. 3. The liquid crystal display certification device according to claim 1, wherein the illumination control unit sets the delay time until the display segment of the display panel at the detected temperature switches from the transmission state to the diffusion state. Liquid crystal display illuminating device, wherein the setting is shorter than the time. 4. The liquid crystal display lighting device according to claim 1, wherein the lighting control unit sets the light emission time to a time during or during which a display segment of the display panel switches from the transmission state to the diffusion state. A liquid crystal display lighting device characterized by being set for a long time. 5. The liquid crystal display lighting device according to claim 1, wherein a light meter for measuring the brightness of the display panel or the vicinity thereof is provided, and wherein a light meter value of the light meter is not less than a predetermined luminance. A liquid crystal display lighting device comprising: a light emission prohibition unit for prohibiting light emission of a lighting unit. 6. The liquid crystal display lighting device according to claim 1, wherein the lighting unit includes: a light source that generates light; and a light guide unit that guides light from the light source to the display panel. Liquid crystal display lighting device.